1 /*
2 * Copyright 1999-2009 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 // do not include precompiled header file
26 # include "incls/_os_linux.cpp.incl"
27
28 // put OS-includes here
29 # include <sys/types.h>
30 # include <sys/mman.h>
31 # include <pthread.h>
32 # include <signal.h>
33 # include <errno.h>
34 # include <dlfcn.h>
35 # include <stdio.h>
36 # include <unistd.h>
37 # include <sys/resource.h>
38 # include <pthread.h>
39 # include <sys/stat.h>
40 # include <sys/time.h>
41 # include <sys/times.h>
42 # include <sys/utsname.h>
43 # include <sys/socket.h>
44 # include <sys/wait.h>
45 # include <pwd.h>
46 # include <poll.h>
47 # include <semaphore.h>
48 # include <fcntl.h>
49 # include <string.h>
50 # include <syscall.h>
51 # include <sys/sysinfo.h>
52 # include <gnu/libc-version.h>
53 # include <sys/ipc.h>
54 # include <sys/shm.h>
55 # include <link.h>
56
57 #define MAX_PATH (2 * K)
58
59 // for timer info max values which include all bits
60 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
61 #define SEC_IN_NANOSECS 1000000000LL
62
63 ////////////////////////////////////////////////////////////////////////////////
64 // global variables
65 julong os::Linux::_physical_memory = 0;
66
67 address os::Linux::_initial_thread_stack_bottom = NULL;
68 uintptr_t os::Linux::_initial_thread_stack_size = 0;
69
70 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
71 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
72 Mutex* os::Linux::_createThread_lock = NULL;
73 pthread_t os::Linux::_main_thread;
74 int os::Linux::_page_size = -1;
75 bool os::Linux::_is_floating_stack = false;
76 bool os::Linux::_is_NPTL = false;
77 bool os::Linux::_supports_fast_thread_cpu_time = false;
78 const char * os::Linux::_glibc_version = NULL;
79 const char * os::Linux::_libpthread_version = NULL;
80
81 static jlong initial_time_count=0;
82
83 static int clock_tics_per_sec = 100;
84
85 // For diagnostics to print a message once. see run_periodic_checks
86 static sigset_t check_signal_done;
87 static bool check_signals = true;;
88
89 static pid_t _initial_pid = 0;
90
91 /* Signal number used to suspend/resume a thread */
92
93 /* do not use any signal number less than SIGSEGV, see 4355769 */
94 static int SR_signum = SIGUSR2;
95 sigset_t SR_sigset;
96
97 /* Used to protect dlsym() calls */
98 static pthread_mutex_t dl_mutex;
99
100 ////////////////////////////////////////////////////////////////////////////////
101 // utility functions
102
103 static int SR_initialize();
104 static int SR_finalize();
105
106 julong os::available_memory() {
107 return Linux::available_memory();
108 }
109
110 julong os::Linux::available_memory() {
111 // values in struct sysinfo are "unsigned long"
112 struct sysinfo si;
113 sysinfo(&si);
114
115 return (julong)si.freeram * si.mem_unit;
116 }
117
118 julong os::physical_memory() {
119 return Linux::physical_memory();
120 }
121
122 julong os::allocatable_physical_memory(julong size) {
123 #ifdef _LP64
124 return size;
125 #else
126 julong result = MIN2(size, (julong)3800*M);
127 if (!is_allocatable(result)) {
128 // See comments under solaris for alignment considerations
129 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
130 result = MIN2(size, reasonable_size);
131 }
132 return result;
133 #endif // _LP64
134 }
135
136 ////////////////////////////////////////////////////////////////////////////////
137 // environment support
138
139 bool os::getenv(const char* name, char* buf, int len) {
140 const char* val = ::getenv(name);
141 if (val != NULL && strlen(val) < (size_t)len) {
142 strcpy(buf, val);
143 return true;
144 }
145 if (len > 0) buf[0] = 0; // return a null string
146 return false;
147 }
148
149
150 // Return true if user is running as root.
151
152 bool os::have_special_privileges() {
153 static bool init = false;
154 static bool privileges = false;
155 if (!init) {
156 privileges = (getuid() != geteuid()) || (getgid() != getegid());
157 init = true;
158 }
159 return privileges;
160 }
161
162
163 #ifndef SYS_gettid
164 // i386: 224, ia64: 1105, amd64: 186, sparc 143
165 #ifdef __ia64__
166 #define SYS_gettid 1105
167 #elif __i386__
168 #define SYS_gettid 224
169 #elif __amd64__
170 #define SYS_gettid 186
171 #elif __sparc__
172 #define SYS_gettid 143
173 #else
174 #error define gettid for the arch
175 #endif
176 #endif
177
178 // Cpu architecture string
179 #if defined(IA64)
180 static char cpu_arch[] = "ia64";
181 #elif defined(IA32)
182 static char cpu_arch[] = "i386";
183 #elif defined(AMD64)
184 static char cpu_arch[] = "amd64";
185 #elif defined(SPARC)
186 # ifdef _LP64
187 static char cpu_arch[] = "sparcv9";
188 # else
189 static char cpu_arch[] = "sparc";
190 # endif
191 #else
192 #error Add appropriate cpu_arch setting
193 #endif
194
195
196 // pid_t gettid()
197 //
198 // Returns the kernel thread id of the currently running thread. Kernel
199 // thread id is used to access /proc.
200 //
201 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
202 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
203 //
204 pid_t os::Linux::gettid() {
205 int rslt = syscall(SYS_gettid);
206 if (rslt == -1) {
207 // old kernel, no NPTL support
208 return getpid();
209 } else {
210 return (pid_t)rslt;
211 }
212 }
213
214 // Most versions of linux have a bug where the number of processors are
215 // determined by looking at the /proc file system. In a chroot environment,
216 // the system call returns 1. This causes the VM to act as if it is
217 // a single processor and elide locking (see is_MP() call).
218 static bool unsafe_chroot_detected = false;
219 static const char *unstable_chroot_error = "/proc file system not found.\n"
220 "Java may be unstable running multithreaded in a chroot "
221 "environment on Linux when /proc filesystem is not mounted.";
222
223 void os::Linux::initialize_system_info() {
224 _processor_count = sysconf(_SC_NPROCESSORS_CONF);
225 if (_processor_count == 1) {
226 pid_t pid = os::Linux::gettid();
227 char fname[32];
228 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
229 FILE *fp = fopen(fname, "r");
230 if (fp == NULL) {
231 unsafe_chroot_detected = true;
232 } else {
233 fclose(fp);
234 }
235 }
236 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
237 assert(_processor_count > 0, "linux error");
238 }
239
240 void os::init_system_properties_values() {
241 // char arch[12];
242 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
243
244 // The next steps are taken in the product version:
245 //
246 // Obtain the JAVA_HOME value from the location of libjvm[_g].so.
247 // This library should be located at:
248 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so.
249 //
250 // If "/jre/lib/" appears at the right place in the path, then we
251 // assume libjvm[_g].so is installed in a JDK and we use this path.
252 //
253 // Otherwise exit with message: "Could not create the Java virtual machine."
254 //
255 // The following extra steps are taken in the debugging version:
256 //
257 // If "/jre/lib/" does NOT appear at the right place in the path
258 // instead of exit check for $JAVA_HOME environment variable.
259 //
260 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
261 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so
262 // it looks like libjvm[_g].so is installed there
263 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so.
264 //
265 // Otherwise exit.
266 //
267 // Important note: if the location of libjvm.so changes this
268 // code needs to be changed accordingly.
269
270 // The next few definitions allow the code to be verbatim:
271 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n))
272 #define getenv(n) ::getenv(n)
273
274 /*
275 * See ld(1):
276 * The linker uses the following search paths to locate required
277 * shared libraries:
278 * 1: ...
279 * ...
280 * 7: The default directories, normally /lib and /usr/lib.
281 */
282 #define DEFAULT_LIBPATH "/lib:/usr/lib"
283
284 #define EXTENSIONS_DIR "/lib/ext"
285 #define ENDORSED_DIR "/lib/endorsed"
286 #define REG_DIR "/usr/java/packages"
287
288 {
289 /* sysclasspath, java_home, dll_dir */
290 {
291 char *home_path;
292 char *dll_path;
293 char *pslash;
294 char buf[MAXPATHLEN];
295 os::jvm_path(buf, sizeof(buf));
296
297 // Found the full path to libjvm.so.
298 // Now cut the path to <java_home>/jre if we can.
299 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
300 pslash = strrchr(buf, '/');
301 if (pslash != NULL)
302 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
303 dll_path = malloc(strlen(buf) + 1);
304 if (dll_path == NULL)
305 return;
306 strcpy(dll_path, buf);
307 Arguments::set_dll_dir(dll_path);
308
309 if (pslash != NULL) {
310 pslash = strrchr(buf, '/');
311 if (pslash != NULL) {
312 *pslash = '\0'; /* get rid of /<arch> */
313 pslash = strrchr(buf, '/');
314 if (pslash != NULL)
315 *pslash = '\0'; /* get rid of /lib */
316 }
317 }
318
319 home_path = malloc(strlen(buf) + 1);
320 if (home_path == NULL)
321 return;
322 strcpy(home_path, buf);
323 Arguments::set_java_home(home_path);
324
325 if (!set_boot_path('/', ':'))
326 return;
327 }
328
329 /*
330 * Where to look for native libraries
331 *
332 * Note: Due to a legacy implementation, most of the library path
333 * is set in the launcher. This was to accomodate linking restrictions
334 * on legacy Linux implementations (which are no longer supported).
335 * Eventually, all the library path setting will be done here.
336 *
337 * However, to prevent the proliferation of improperly built native
338 * libraries, the new path component /usr/java/packages is added here.
339 * Eventually, all the library path setting will be done here.
340 */
341 {
342 char *ld_library_path;
343
344 /*
345 * Construct the invariant part of ld_library_path. Note that the
346 * space for the colon and the trailing null are provided by the
347 * nulls included by the sizeof operator (so actually we allocate
348 * a byte more than necessary).
349 */
350 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
351 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
352 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
353
354 /*
355 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
356 * should always exist (until the legacy problem cited above is
357 * addressed).
358 */
359 char *v = getenv("LD_LIBRARY_PATH");
360 if (v != NULL) {
361 char *t = ld_library_path;
362 /* That's +1 for the colon and +1 for the trailing '\0' */
363 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
364 sprintf(ld_library_path, "%s:%s", v, t);
365 }
366 Arguments::set_library_path(ld_library_path);
367 }
368
369 /*
370 * Extensions directories.
371 *
372 * Note that the space for the colon and the trailing null are provided
373 * by the nulls included by the sizeof operator (so actually one byte more
374 * than necessary is allocated).
375 */
376 {
377 char *buf = malloc(strlen(Arguments::get_java_home()) +
378 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
379 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
380 Arguments::get_java_home());
381 Arguments::set_ext_dirs(buf);
382 }
383
384 /* Endorsed standards default directory. */
385 {
386 char * buf;
387 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
388 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
389 Arguments::set_endorsed_dirs(buf);
390 }
391 }
392
393 #undef malloc
394 #undef getenv
395 #undef EXTENSIONS_DIR
396 #undef ENDORSED_DIR
397
398 // Done
399 return;
400 }
401
402 ////////////////////////////////////////////////////////////////////////////////
403 // breakpoint support
404
405 void os::breakpoint() {
406 BREAKPOINT;
407 }
408
409 extern "C" void breakpoint() {
410 // use debugger to set breakpoint here
411 }
412
413 ////////////////////////////////////////////////////////////////////////////////
414 // signal support
415
416 debug_only(static bool signal_sets_initialized = false);
417 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
418
419 bool os::Linux::is_sig_ignored(int sig) {
420 struct sigaction oact;
421 sigaction(sig, (struct sigaction*)NULL, &oact);
422 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
423 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
424 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
425 return true;
426 else
427 return false;
428 }
429
430 void os::Linux::signal_sets_init() {
431 // Should also have an assertion stating we are still single-threaded.
432 assert(!signal_sets_initialized, "Already initialized");
433 // Fill in signals that are necessarily unblocked for all threads in
434 // the VM. Currently, we unblock the following signals:
435 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
436 // by -Xrs (=ReduceSignalUsage));
437 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
438 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
439 // the dispositions or masks wrt these signals.
440 // Programs embedding the VM that want to use the above signals for their
441 // own purposes must, at this time, use the "-Xrs" option to prevent
442 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
443 // (See bug 4345157, and other related bugs).
444 // In reality, though, unblocking these signals is really a nop, since
445 // these signals are not blocked by default.
446 sigemptyset(&unblocked_sigs);
447 sigemptyset(&allowdebug_blocked_sigs);
448 sigaddset(&unblocked_sigs, SIGILL);
449 sigaddset(&unblocked_sigs, SIGSEGV);
450 sigaddset(&unblocked_sigs, SIGBUS);
451 sigaddset(&unblocked_sigs, SIGFPE);
452 sigaddset(&unblocked_sigs, SR_signum);
453
454 if (!ReduceSignalUsage) {
455 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
456 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
457 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
458 }
459 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
460 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
461 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
462 }
463 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
464 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
465 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
466 }
467 }
468 // Fill in signals that are blocked by all but the VM thread.
469 sigemptyset(&vm_sigs);
470 if (!ReduceSignalUsage)
471 sigaddset(&vm_sigs, BREAK_SIGNAL);
472 debug_only(signal_sets_initialized = true);
473
474 }
475
476 // These are signals that are unblocked while a thread is running Java.
477 // (For some reason, they get blocked by default.)
478 sigset_t* os::Linux::unblocked_signals() {
479 assert(signal_sets_initialized, "Not initialized");
480 return &unblocked_sigs;
481 }
482
483 // These are the signals that are blocked while a (non-VM) thread is
484 // running Java. Only the VM thread handles these signals.
485 sigset_t* os::Linux::vm_signals() {
486 assert(signal_sets_initialized, "Not initialized");
487 return &vm_sigs;
488 }
489
490 // These are signals that are blocked during cond_wait to allow debugger in
491 sigset_t* os::Linux::allowdebug_blocked_signals() {
492 assert(signal_sets_initialized, "Not initialized");
493 return &allowdebug_blocked_sigs;
494 }
495
496 void os::Linux::hotspot_sigmask(Thread* thread) {
497
498 //Save caller's signal mask before setting VM signal mask
499 sigset_t caller_sigmask;
500 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
501
502 OSThread* osthread = thread->osthread();
503 osthread->set_caller_sigmask(caller_sigmask);
504
505 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
506
507 if (!ReduceSignalUsage) {
508 if (thread->is_VM_thread()) {
509 // Only the VM thread handles BREAK_SIGNAL ...
510 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
511 } else {
512 // ... all other threads block BREAK_SIGNAL
513 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
514 }
515 }
516 }
517
518 //////////////////////////////////////////////////////////////////////////////
519 // detecting pthread library
520
521 void os::Linux::libpthread_init() {
522 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
523 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
524 // generic name for earlier versions.
525 // Define macros here so we can build HotSpot on old systems.
526 # ifndef _CS_GNU_LIBC_VERSION
527 # define _CS_GNU_LIBC_VERSION 2
528 # endif
529 # ifndef _CS_GNU_LIBPTHREAD_VERSION
530 # define _CS_GNU_LIBPTHREAD_VERSION 3
531 # endif
532
533 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
534 if (n > 0) {
535 char *str = (char *)malloc(n);
536 confstr(_CS_GNU_LIBC_VERSION, str, n);
537 os::Linux::set_glibc_version(str);
538 } else {
539 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
540 static char _gnu_libc_version[32];
541 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
542 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
543 os::Linux::set_glibc_version(_gnu_libc_version);
544 }
545
546 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
547 if (n > 0) {
548 char *str = (char *)malloc(n);
549 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
550 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
551 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
552 // is the case. LinuxThreads has a hard limit on max number of threads.
553 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
554 // On the other hand, NPTL does not have such a limit, sysconf()
555 // will return -1 and errno is not changed. Check if it is really NPTL.
556 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
557 strstr(str, "NPTL") &&
558 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
559 free(str);
560 os::Linux::set_libpthread_version("linuxthreads");
561 } else {
562 os::Linux::set_libpthread_version(str);
563 }
564 } else {
565 // glibc before 2.3.2 only has LinuxThreads.
566 os::Linux::set_libpthread_version("linuxthreads");
567 }
568
569 if (strstr(libpthread_version(), "NPTL")) {
570 os::Linux::set_is_NPTL();
571 } else {
572 os::Linux::set_is_LinuxThreads();
573 }
574
575 // LinuxThreads have two flavors: floating-stack mode, which allows variable
576 // stack size; and fixed-stack mode. NPTL is always floating-stack.
577 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
578 os::Linux::set_is_floating_stack();
579 }
580 }
581
582 /////////////////////////////////////////////////////////////////////////////
583 // thread stack
584
585 // Force Linux kernel to expand current thread stack. If "bottom" is close
586 // to the stack guard, caller should block all signals.
587 //
588 // MAP_GROWSDOWN:
589 // A special mmap() flag that is used to implement thread stacks. It tells
590 // kernel that the memory region should extend downwards when needed. This
591 // allows early versions of LinuxThreads to only mmap the first few pages
592 // when creating a new thread. Linux kernel will automatically expand thread
593 // stack as needed (on page faults).
594 //
595 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
596 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
597 // region, it's hard to tell if the fault is due to a legitimate stack
598 // access or because of reading/writing non-exist memory (e.g. buffer
599 // overrun). As a rule, if the fault happens below current stack pointer,
600 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
601 // application (see Linux kernel fault.c).
602 //
603 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
604 // stack overflow detection.
605 //
606 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
607 // not use this flag. However, the stack of initial thread is not created
608 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
609 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
610 // and then attach the thread to JVM.
611 //
612 // To get around the problem and allow stack banging on Linux, we need to
613 // manually expand thread stack after receiving the SIGSEGV.
614 //
615 // There are two ways to expand thread stack to address "bottom", we used
616 // both of them in JVM before 1.5:
617 // 1. adjust stack pointer first so that it is below "bottom", and then
618 // touch "bottom"
619 // 2. mmap() the page in question
620 //
621 // Now alternate signal stack is gone, it's harder to use 2. For instance,
622 // if current sp is already near the lower end of page 101, and we need to
623 // call mmap() to map page 100, it is possible that part of the mmap() frame
624 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
625 // That will destroy the mmap() frame and cause VM to crash.
626 //
627 // The following code works by adjusting sp first, then accessing the "bottom"
628 // page to force a page fault. Linux kernel will then automatically expand the
629 // stack mapping.
630 //
631 // _expand_stack_to() assumes its frame size is less than page size, which
632 // should always be true if the function is not inlined.
633
634 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
635 #define NOINLINE
636 #else
637 #define NOINLINE __attribute__ ((noinline))
638 #endif
639
640 static void _expand_stack_to(address bottom) NOINLINE;
641
642 static void _expand_stack_to(address bottom) {
643 address sp;
644 size_t size;
645 volatile char *p;
646
647 // Adjust bottom to point to the largest address within the same page, it
648 // gives us a one-page buffer if alloca() allocates slightly more memory.
649 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
650 bottom += os::Linux::page_size() - 1;
651
652 // sp might be slightly above current stack pointer; if that's the case, we
653 // will alloca() a little more space than necessary, which is OK. Don't use
654 // os::current_stack_pointer(), as its result can be slightly below current
655 // stack pointer, causing us to not alloca enough to reach "bottom".
656 sp = (address)&sp;
657
658 if (sp > bottom) {
659 size = sp - bottom;
660 p = (volatile char *)alloca(size);
661 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
662 p[0] = '\0';
663 }
664 }
665
666 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
667 assert(t!=NULL, "just checking");
668 assert(t->osthread()->expanding_stack(), "expand should be set");
669 assert(t->stack_base() != NULL, "stack_base was not initialized");
670
671 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
672 sigset_t mask_all, old_sigset;
673 sigfillset(&mask_all);
674 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
675 _expand_stack_to(addr);
676 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
677 return true;
678 }
679 return false;
680 }
681
682 //////////////////////////////////////////////////////////////////////////////
683 // create new thread
684
685 static address highest_vm_reserved_address();
686
687 // check if it's safe to start a new thread
688 static bool _thread_safety_check(Thread* thread) {
689 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
690 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
691 // Heap is mmap'ed at lower end of memory space. Thread stacks are
692 // allocated (MAP_FIXED) from high address space. Every thread stack
693 // occupies a fixed size slot (usually 2Mbytes, but user can change
694 // it to other values if they rebuild LinuxThreads).
695 //
696 // Problem with MAP_FIXED is that mmap() can still succeed even part of
697 // the memory region has already been mmap'ed. That means if we have too
698 // many threads and/or very large heap, eventually thread stack will
699 // collide with heap.
700 //
701 // Here we try to prevent heap/stack collision by comparing current
702 // stack bottom with the highest address that has been mmap'ed by JVM
703 // plus a safety margin for memory maps created by native code.
704 //
705 // This feature can be disabled by setting ThreadSafetyMargin to 0
706 //
707 if (ThreadSafetyMargin > 0) {
708 address stack_bottom = os::current_stack_base() - os::current_stack_size();
709
710 // not safe if our stack extends below the safety margin
711 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
712 } else {
713 return true;
714 }
715 } else {
716 // Floating stack LinuxThreads or NPTL:
717 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
718 // there's not enough space left, pthread_create() will fail. If we come
719 // here, that means enough space has been reserved for stack.
720 return true;
721 }
722 }
723
724 // Thread start routine for all newly created threads
725 static void *java_start(Thread *thread) {
726 // Try to randomize the cache line index of hot stack frames.
727 // This helps when threads of the same stack traces evict each other's
728 // cache lines. The threads can be either from the same JVM instance, or
729 // from different JVM instances. The benefit is especially true for
730 // processors with hyperthreading technology.
731 static int counter = 0;
732 int pid = os::current_process_id();
733 alloca(((pid ^ counter++) & 7) * 128);
734
735 ThreadLocalStorage::set_thread(thread);
736
737 OSThread* osthread = thread->osthread();
738 Monitor* sync = osthread->startThread_lock();
739
740 // non floating stack LinuxThreads needs extra check, see above
741 if (!_thread_safety_check(thread)) {
742 // notify parent thread
743 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
744 osthread->set_state(ZOMBIE);
745 sync->notify_all();
746 return NULL;
747 }
748
749 // thread_id is kernel thread id (similar to Solaris LWP id)
750 osthread->set_thread_id(os::Linux::gettid());
751
752 if (UseNUMA) {
753 int lgrp_id = os::numa_get_group_id();
754 if (lgrp_id != -1) {
755 thread->set_lgrp_id(lgrp_id);
756 }
757 }
758 // initialize signal mask for this thread
759 os::Linux::hotspot_sigmask(thread);
760
761 // initialize floating point control register
762 os::Linux::init_thread_fpu_state();
763
764 // handshaking with parent thread
765 {
766 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
767
768 // notify parent thread
769 osthread->set_state(INITIALIZED);
770 sync->notify_all();
771
772 // wait until os::start_thread()
773 while (osthread->get_state() == INITIALIZED) {
774 sync->wait(Mutex::_no_safepoint_check_flag);
775 }
776 }
777
778 // call one more level start routine
779 thread->run();
780
781 return 0;
782 }
783
784 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
785 assert(thread->osthread() == NULL, "caller responsible");
786
787 // Allocate the OSThread object
788 OSThread* osthread = new OSThread(NULL, NULL);
789 if (osthread == NULL) {
790 return false;
791 }
792
793 // set the correct thread state
794 osthread->set_thread_type(thr_type);
795
796 // Initial state is ALLOCATED but not INITIALIZED
797 osthread->set_state(ALLOCATED);
798
799 thread->set_osthread(osthread);
800
801 // init thread attributes
802 pthread_attr_t attr;
803 pthread_attr_init(&attr);
804 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
805
806 // stack size
807 if (os::Linux::supports_variable_stack_size()) {
808 // calculate stack size if it's not specified by caller
809 if (stack_size == 0) {
810 stack_size = os::Linux::default_stack_size(thr_type);
811
812 switch (thr_type) {
813 case os::java_thread:
814 // Java threads use ThreadStackSize which default value can be changed with the flag -Xss
815 if (JavaThread::stack_size_at_create() > 0) stack_size = JavaThread::stack_size_at_create();
816 break;
817 case os::compiler_thread:
818 if (CompilerThreadStackSize > 0) {
819 stack_size = (size_t)(CompilerThreadStackSize * K);
820 break;
821 } // else fall through:
822 // use VMThreadStackSize if CompilerThreadStackSize is not defined
823 case os::vm_thread:
824 case os::pgc_thread:
825 case os::cgc_thread:
826 case os::watcher_thread:
827 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
828 break;
829 }
830 }
831
832 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
833 pthread_attr_setstacksize(&attr, stack_size);
834 } else {
835 // let pthread_create() pick the default value.
836 }
837
838 // glibc guard page
839 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
840
841 ThreadState state;
842
843 {
844 // Serialize thread creation if we are running with fixed stack LinuxThreads
845 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
846 if (lock) {
847 os::Linux::createThread_lock()->lock_without_safepoint_check();
848 }
849
850 pthread_t tid;
851 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
852
853 pthread_attr_destroy(&attr);
854
855 if (ret != 0) {
856 if (PrintMiscellaneous && (Verbose || WizardMode)) {
857 perror("pthread_create()");
858 }
859 // Need to clean up stuff we've allocated so far
860 thread->set_osthread(NULL);
861 delete osthread;
862 if (lock) os::Linux::createThread_lock()->unlock();
863 return false;
864 }
865
866 // Store pthread info into the OSThread
867 osthread->set_pthread_id(tid);
868
869 // Wait until child thread is either initialized or aborted
870 {
871 Monitor* sync_with_child = osthread->startThread_lock();
872 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
873 while ((state = osthread->get_state()) == ALLOCATED) {
874 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
875 }
876 }
877
878 if (lock) {
879 os::Linux::createThread_lock()->unlock();
880 }
881 }
882
883 // Aborted due to thread limit being reached
884 if (state == ZOMBIE) {
885 thread->set_osthread(NULL);
886 delete osthread;
887 return false;
888 }
889
890 // The thread is returned suspended (in state INITIALIZED),
891 // and is started higher up in the call chain
892 assert(state == INITIALIZED, "race condition");
893 return true;
894 }
895
896 /////////////////////////////////////////////////////////////////////////////
897 // attach existing thread
898
899 // bootstrap the main thread
900 bool os::create_main_thread(JavaThread* thread) {
901 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
902 return create_attached_thread(thread);
903 }
904
905 bool os::create_attached_thread(JavaThread* thread) {
906 #ifdef ASSERT
907 thread->verify_not_published();
908 #endif
909
910 // Allocate the OSThread object
911 OSThread* osthread = new OSThread(NULL, NULL);
912
913 if (osthread == NULL) {
914 return false;
915 }
916
917 // Store pthread info into the OSThread
918 osthread->set_thread_id(os::Linux::gettid());
919 osthread->set_pthread_id(::pthread_self());
920
921 // initialize floating point control register
922 os::Linux::init_thread_fpu_state();
923
924 // Initial thread state is RUNNABLE
925 osthread->set_state(RUNNABLE);
926
927 thread->set_osthread(osthread);
928
929 if (UseNUMA) {
930 int lgrp_id = os::numa_get_group_id();
931 if (lgrp_id != -1) {
932 thread->set_lgrp_id(lgrp_id);
933 }
934 }
935
936 if (os::Linux::is_initial_thread()) {
937 // If current thread is initial thread, its stack is mapped on demand,
938 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
939 // the entire stack region to avoid SEGV in stack banging.
940 // It is also useful to get around the heap-stack-gap problem on SuSE
941 // kernel (see 4821821 for details). We first expand stack to the top
942 // of yellow zone, then enable stack yellow zone (order is significant,
943 // enabling yellow zone first will crash JVM on SuSE Linux), so there
944 // is no gap between the last two virtual memory regions.
945
946 JavaThread *jt = (JavaThread *)thread;
947 address addr = jt->stack_yellow_zone_base();
948 assert(addr != NULL, "initialization problem?");
949 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
950
951 osthread->set_expanding_stack();
952 os::Linux::manually_expand_stack(jt, addr);
953 osthread->clear_expanding_stack();
954 }
955
956 // initialize signal mask for this thread
957 // and save the caller's signal mask
958 os::Linux::hotspot_sigmask(thread);
959
960 return true;
961 }
962
963 void os::pd_start_thread(Thread* thread) {
964 OSThread * osthread = thread->osthread();
965 assert(osthread->get_state() != INITIALIZED, "just checking");
966 Monitor* sync_with_child = osthread->startThread_lock();
967 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
968 sync_with_child->notify();
969 }
970
971 // Free Linux resources related to the OSThread
972 void os::free_thread(OSThread* osthread) {
973 assert(osthread != NULL, "osthread not set");
974
975 if (Thread::current()->osthread() == osthread) {
976 // Restore caller's signal mask
977 sigset_t sigmask = osthread->caller_sigmask();
978 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
979 }
980
981 delete osthread;
982 }
983
984 //////////////////////////////////////////////////////////////////////////////
985 // thread local storage
986
987 int os::allocate_thread_local_storage() {
988 pthread_key_t key;
989 int rslt = pthread_key_create(&key, NULL);
990 assert(rslt == 0, "cannot allocate thread local storage");
991 return (int)key;
992 }
993
994 // Note: This is currently not used by VM, as we don't destroy TLS key
995 // on VM exit.
996 void os::free_thread_local_storage(int index) {
997 int rslt = pthread_key_delete((pthread_key_t)index);
998 assert(rslt == 0, "invalid index");
999 }
1000
1001 void os::thread_local_storage_at_put(int index, void* value) {
1002 int rslt = pthread_setspecific((pthread_key_t)index, value);
1003 assert(rslt == 0, "pthread_setspecific failed");
1004 }
1005
1006 extern "C" Thread* get_thread() {
1007 return ThreadLocalStorage::thread();
1008 }
1009
1010 //////////////////////////////////////////////////////////////////////////////
1011 // initial thread
1012
1013 // Check if current thread is the initial thread, similar to Solaris thr_main.
1014 bool os::Linux::is_initial_thread(void) {
1015 char dummy;
1016 // If called before init complete, thread stack bottom will be null.
1017 // Can be called if fatal error occurs before initialization.
1018 if (initial_thread_stack_bottom() == NULL) return false;
1019 assert(initial_thread_stack_bottom() != NULL &&
1020 initial_thread_stack_size() != 0,
1021 "os::init did not locate initial thread's stack region");
1022 if ((address)&dummy >= initial_thread_stack_bottom() &&
1023 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1024 return true;
1025 else return false;
1026 }
1027
1028 // Find the virtual memory area that contains addr
1029 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1030 FILE *fp = fopen("/proc/self/maps", "r");
1031 if (fp) {
1032 address low, high;
1033 while (!feof(fp)) {
1034 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1035 if (low <= addr && addr < high) {
1036 if (vma_low) *vma_low = low;
1037 if (vma_high) *vma_high = high;
1038 fclose (fp);
1039 return true;
1040 }
1041 }
1042 for (;;) {
1043 int ch = fgetc(fp);
1044 if (ch == EOF || ch == (int)'\n') break;
1045 }
1046 }
1047 fclose(fp);
1048 }
1049 return false;
1050 }
1051
1052 // Locate initial thread stack. This special handling of initial thread stack
1053 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1054 // bogus value for initial thread.
1055 void os::Linux::capture_initial_stack(size_t max_size) {
1056 // stack size is the easy part, get it from RLIMIT_STACK
1057 size_t stack_size;
1058 struct rlimit rlim;
1059 getrlimit(RLIMIT_STACK, &rlim);
1060 stack_size = rlim.rlim_cur;
1061
1062 // 6308388: a bug in ld.so will relocate its own .data section to the
1063 // lower end of primordial stack; reduce ulimit -s value a little bit
1064 // so we won't install guard page on ld.so's data section.
1065 stack_size -= 2 * page_size();
1066
1067 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1068 // 7.1, in both cases we will get 2G in return value.
1069 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1070 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1071 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1072 // in case other parts in glibc still assumes 2M max stack size.
1073 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1074 #ifndef IA64
1075 if (stack_size > 2 * K * K) stack_size = 2 * K * K;
1076 #else
1077 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1078 if (stack_size > 4 * K * K) stack_size = 4 * K * K;
1079 #endif
1080
1081 // Try to figure out where the stack base (top) is. This is harder.
1082 //
1083 // When an application is started, glibc saves the initial stack pointer in
1084 // a global variable "__libc_stack_end", which is then used by system
1085 // libraries. __libc_stack_end should be pretty close to stack top. The
1086 // variable is available since the very early days. However, because it is
1087 // a private interface, it could disappear in the future.
1088 //
1089 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1090 // to __libc_stack_end, it is very close to stack top, but isn't the real
1091 // stack top. Note that /proc may not exist if VM is running as a chroot
1092 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1093 // /proc/<pid>/stat could change in the future (though unlikely).
1094 //
1095 // We try __libc_stack_end first. If that doesn't work, look for
1096 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1097 // as a hint, which should work well in most cases.
1098
1099 uintptr_t stack_start;
1100
1101 // try __libc_stack_end first
1102 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1103 if (p && *p) {
1104 stack_start = *p;
1105 } else {
1106 // see if we can get the start_stack field from /proc/self/stat
1107 FILE *fp;
1108 int pid;
1109 char state;
1110 int ppid;
1111 int pgrp;
1112 int session;
1113 int nr;
1114 int tpgrp;
1115 unsigned long flags;
1116 unsigned long minflt;
1117 unsigned long cminflt;
1118 unsigned long majflt;
1119 unsigned long cmajflt;
1120 unsigned long utime;
1121 unsigned long stime;
1122 long cutime;
1123 long cstime;
1124 long prio;
1125 long nice;
1126 long junk;
1127 long it_real;
1128 uintptr_t start;
1129 uintptr_t vsize;
1130 uintptr_t rss;
1131 unsigned long rsslim;
1132 uintptr_t scodes;
1133 uintptr_t ecode;
1134 int i;
1135
1136 // Figure what the primordial thread stack base is. Code is inspired
1137 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1138 // followed by command name surrounded by parentheses, state, etc.
1139 char stat[2048];
1140 int statlen;
1141
1142 fp = fopen("/proc/self/stat", "r");
1143 if (fp) {
1144 statlen = fread(stat, 1, 2047, fp);
1145 stat[statlen] = '\0';
1146 fclose(fp);
1147
1148 // Skip pid and the command string. Note that we could be dealing with
1149 // weird command names, e.g. user could decide to rename java launcher
1150 // to "java 1.4.2 :)", then the stat file would look like
1151 // 1234 (java 1.4.2 :)) R ... ...
1152 // We don't really need to know the command string, just find the last
1153 // occurrence of ")" and then start parsing from there. See bug 4726580.
1154 char * s = strrchr(stat, ')');
1155
1156 i = 0;
1157 if (s) {
1158 // Skip blank chars
1159 do s++; while (isspace(*s));
1160
1161 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1162 /* 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 */
1163 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld "
1164 UINTX_FORMAT UINTX_FORMAT UINTX_FORMAT
1165 " %lu "
1166 UINTX_FORMAT UINTX_FORMAT UINTX_FORMAT,
1167 &state, /* 3 %c */
1168 &ppid, /* 4 %d */
1169 &pgrp, /* 5 %d */
1170 &session, /* 6 %d */
1171 &nr, /* 7 %d */
1172 &tpgrp, /* 8 %d */
1173 &flags, /* 9 %lu */
1174 &minflt, /* 10 %lu */
1175 &cminflt, /* 11 %lu */
1176 &majflt, /* 12 %lu */
1177 &cmajflt, /* 13 %lu */
1178 &utime, /* 14 %lu */
1179 &stime, /* 15 %lu */
1180 &cutime, /* 16 %ld */
1181 &cstime, /* 17 %ld */
1182 &prio, /* 18 %ld */
1183 &nice, /* 19 %ld */
1184 &junk, /* 20 %ld */
1185 &it_real, /* 21 %ld */
1186 &start, /* 22 UINTX_FORMAT */
1187 &vsize, /* 23 UINTX_FORMAT */
1188 &rss, /* 24 UINTX_FORMAT */
1189 &rsslim, /* 25 %lu */
1190 &scodes, /* 26 UINTX_FORMAT */
1191 &ecode, /* 27 UINTX_FORMAT */
1192 &stack_start); /* 28 UINTX_FORMAT */
1193 }
1194
1195 if (i != 28 - 2) {
1196 assert(false, "Bad conversion from /proc/self/stat");
1197 // product mode - assume we are the initial thread, good luck in the
1198 // embedded case.
1199 warning("Can't detect initial thread stack location - bad conversion");
1200 stack_start = (uintptr_t) &rlim;
1201 }
1202 } else {
1203 // For some reason we can't open /proc/self/stat (for example, running on
1204 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1205 // most cases, so don't abort:
1206 warning("Can't detect initial thread stack location - no /proc/self/stat");
1207 stack_start = (uintptr_t) &rlim;
1208 }
1209 }
1210
1211 // Now we have a pointer (stack_start) very close to the stack top, the
1212 // next thing to do is to figure out the exact location of stack top. We
1213 // can find out the virtual memory area that contains stack_start by
1214 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1215 // and its upper limit is the real stack top. (again, this would fail if
1216 // running inside chroot, because /proc may not exist.)
1217
1218 uintptr_t stack_top;
1219 address low, high;
1220 if (find_vma((address)stack_start, &low, &high)) {
1221 // success, "high" is the true stack top. (ignore "low", because initial
1222 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1223 stack_top = (uintptr_t)high;
1224 } else {
1225 // failed, likely because /proc/self/maps does not exist
1226 warning("Can't detect initial thread stack location - find_vma failed");
1227 // best effort: stack_start is normally within a few pages below the real
1228 // stack top, use it as stack top, and reduce stack size so we won't put
1229 // guard page outside stack.
1230 stack_top = stack_start;
1231 stack_size -= 16 * page_size();
1232 }
1233
1234 // stack_top could be partially down the page so align it
1235 stack_top = align_size_up(stack_top, page_size());
1236
1237 if (max_size && stack_size > max_size) {
1238 _initial_thread_stack_size = max_size;
1239 } else {
1240 _initial_thread_stack_size = stack_size;
1241 }
1242
1243 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1244 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1245 }
1246
1247 ////////////////////////////////////////////////////////////////////////////////
1248 // time support
1249
1250 // Time since start-up in seconds to a fine granularity.
1251 // Used by VMSelfDestructTimer and the MemProfiler.
1252 double os::elapsedTime() {
1253
1254 return (double)(os::elapsed_counter()) * 0.000001;
1255 }
1256
1257 jlong os::elapsed_counter() {
1258 timeval time;
1259 int status = gettimeofday(&time, NULL);
1260 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1261 }
1262
1263 jlong os::elapsed_frequency() {
1264 return (1000 * 1000);
1265 }
1266
1267 // For now, we say that linux does not support vtime. I have no idea
1268 // whether it can actually be made to (DLD, 9/13/05).
1269
1270 bool os::supports_vtime() { return false; }
1271 bool os::enable_vtime() { return false; }
1272 bool os::vtime_enabled() { return false; }
1273 double os::elapsedVTime() {
1274 // better than nothing, but not much
1275 return elapsedTime();
1276 }
1277
1278 jlong os::javaTimeMillis() {
1279 timeval time;
1280 int status = gettimeofday(&time, NULL);
1281 assert(status != -1, "linux error");
1282 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1283 }
1284
1285 #ifndef CLOCK_MONOTONIC
1286 #define CLOCK_MONOTONIC (1)
1287 #endif
1288
1289 void os::Linux::clock_init() {
1290 // we do dlopen's in this particular order due to bug in linux
1291 // dynamical loader (see 6348968) leading to crash on exit
1292 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1293 if (handle == NULL) {
1294 handle = dlopen("librt.so", RTLD_LAZY);
1295 }
1296
1297 if (handle) {
1298 int (*clock_getres_func)(clockid_t, struct timespec*) =
1299 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1300 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1301 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1302 if (clock_getres_func && clock_gettime_func) {
1303 // See if monotonic clock is supported by the kernel. Note that some
1304 // early implementations simply return kernel jiffies (updated every
1305 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1306 // for nano time (though the monotonic property is still nice to have).
1307 // It's fixed in newer kernels, however clock_getres() still returns
1308 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1309 // resolution for now. Hopefully as people move to new kernels, this
1310 // won't be a problem.
1311 struct timespec res;
1312 struct timespec tp;
1313 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1314 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1315 // yes, monotonic clock is supported
1316 _clock_gettime = clock_gettime_func;
1317 } else {
1318 // close librt if there is no monotonic clock
1319 dlclose(handle);
1320 }
1321 }
1322 }
1323 }
1324
1325 #ifndef SYS_clock_getres
1326
1327 #if defined(IA32) || defined(AMD64)
1328 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1329 #else
1330 #error Value of SYS_clock_getres not known on this platform
1331 #endif
1332
1333 #endif
1334
1335 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1336
1337 void os::Linux::fast_thread_clock_init() {
1338 if (!UseLinuxPosixThreadCPUClocks) {
1339 return;
1340 }
1341 clockid_t clockid;
1342 struct timespec tp;
1343 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1344 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1345
1346 // Switch to using fast clocks for thread cpu time if
1347 // the sys_clock_getres() returns 0 error code.
1348 // Note, that some kernels may support the current thread
1349 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1350 // returned by the pthread_getcpuclockid().
1351 // If the fast Posix clocks are supported then the sys_clock_getres()
1352 // must return at least tp.tv_sec == 0 which means a resolution
1353 // better than 1 sec. This is extra check for reliability.
1354
1355 if(pthread_getcpuclockid_func &&
1356 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1357 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1358
1359 _supports_fast_thread_cpu_time = true;
1360 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1361 }
1362 }
1363
1364 jlong os::javaTimeNanos() {
1365 if (Linux::supports_monotonic_clock()) {
1366 struct timespec tp;
1367 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1368 assert(status == 0, "gettime error");
1369 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1370 return result;
1371 } else {
1372 timeval time;
1373 int status = gettimeofday(&time, NULL);
1374 assert(status != -1, "linux error");
1375 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1376 return 1000 * usecs;
1377 }
1378 }
1379
1380 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1381 if (Linux::supports_monotonic_clock()) {
1382 info_ptr->max_value = ALL_64_BITS;
1383
1384 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1385 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1386 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1387 } else {
1388 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1389 info_ptr->max_value = ALL_64_BITS;
1390
1391 // gettimeofday is a real time clock so it skips
1392 info_ptr->may_skip_backward = true;
1393 info_ptr->may_skip_forward = true;
1394 }
1395
1396 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1397 }
1398
1399 // Return the real, user, and system times in seconds from an
1400 // arbitrary fixed point in the past.
1401 bool os::getTimesSecs(double* process_real_time,
1402 double* process_user_time,
1403 double* process_system_time) {
1404 struct tms ticks;
1405 clock_t real_ticks = times(&ticks);
1406
1407 if (real_ticks == (clock_t) (-1)) {
1408 return false;
1409 } else {
1410 double ticks_per_second = (double) clock_tics_per_sec;
1411 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1412 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1413 *process_real_time = ((double) real_ticks) / ticks_per_second;
1414
1415 return true;
1416 }
1417 }
1418
1419
1420 char * os::local_time_string(char *buf, size_t buflen) {
1421 struct tm t;
1422 time_t long_time;
1423 time(&long_time);
1424 localtime_r(&long_time, &t);
1425 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1426 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1427 t.tm_hour, t.tm_min, t.tm_sec);
1428 return buf;
1429 }
1430
1431 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1432 return localtime_r(clock, res);
1433 }
1434
1435 ////////////////////////////////////////////////////////////////////////////////
1436 // runtime exit support
1437
1438 // Note: os::shutdown() might be called very early during initialization, or
1439 // called from signal handler. Before adding something to os::shutdown(), make
1440 // sure it is async-safe and can handle partially initialized VM.
1441 void os::shutdown() {
1442
1443 // allow PerfMemory to attempt cleanup of any persistent resources
1444 perfMemory_exit();
1445
1446 // needs to remove object in file system
1447 AttachListener::abort();
1448
1449 // flush buffered output, finish log files
1450 ostream_abort();
1451
1452 // Check for abort hook
1453 abort_hook_t abort_hook = Arguments::abort_hook();
1454 if (abort_hook != NULL) {
1455 abort_hook();
1456 }
1457
1458 }
1459
1460 // Note: os::abort() might be called very early during initialization, or
1461 // called from signal handler. Before adding something to os::abort(), make
1462 // sure it is async-safe and can handle partially initialized VM.
1463 void os::abort(bool dump_core) {
1464 os::shutdown();
1465 if (dump_core) {
1466 #ifndef PRODUCT
1467 fdStream out(defaultStream::output_fd());
1468 out.print_raw("Current thread is ");
1469 char buf[16];
1470 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1471 out.print_raw_cr(buf);
1472 out.print_raw_cr("Dumping core ...");
1473 #endif
1474 ::abort(); // dump core
1475 }
1476
1477 ::exit(1);
1478 }
1479
1480 // Die immediately, no exit hook, no abort hook, no cleanup.
1481 void os::die() {
1482 // _exit() on LinuxThreads only kills current thread
1483 ::abort();
1484 }
1485
1486 // unused on linux for now.
1487 void os::set_error_file(const char *logfile) {}
1488
1489 intx os::current_thread_id() { return (intx)pthread_self(); }
1490 int os::current_process_id() {
1491
1492 // Under the old linux thread library, linux gives each thread
1493 // its own process id. Because of this each thread will return
1494 // a different pid if this method were to return the result
1495 // of getpid(2). Linux provides no api that returns the pid
1496 // of the launcher thread for the vm. This implementation
1497 // returns a unique pid, the pid of the launcher thread
1498 // that starts the vm 'process'.
1499
1500 // Under the NPTL, getpid() returns the same pid as the
1501 // launcher thread rather than a unique pid per thread.
1502 // Use gettid() if you want the old pre NPTL behaviour.
1503
1504 // if you are looking for the result of a call to getpid() that
1505 // returns a unique pid for the calling thread, then look at the
1506 // OSThread::thread_id() method in osThread_linux.hpp file
1507
1508 return (int)(_initial_pid ? _initial_pid : getpid());
1509 }
1510
1511 // DLL functions
1512
1513 const char* os::dll_file_extension() { return ".so"; }
1514
1515 const char* os::get_temp_directory() { return "/tmp/"; }
1516
1517 static bool file_exists(const char* filename) {
1518 struct stat statbuf;
1519 if (filename == NULL || strlen(filename) == 0) {
1520 return false;
1521 }
1522 return os::stat(filename, &statbuf) == 0;
1523 }
1524
1525 void os::dll_build_name(char* buffer, size_t buflen,
1526 const char* pname, const char* fname) {
1527 // Copied from libhpi
1528 const size_t pnamelen = pname ? strlen(pname) : 0;
1529
1530 // Quietly truncate on buffer overflow. Should be an error.
1531 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1532 *buffer = '\0';
1533 return;
1534 }
1535
1536 if (pnamelen == 0) {
1537 snprintf(buffer, buflen, "lib%s.so", fname);
1538 } else if (strchr(pname, *os::path_separator()) != NULL) {
1539 int n;
1540 char** pelements = split_path(pname, &n);
1541 for (int i = 0 ; i < n ; i++) {
1542 // Really shouldn't be NULL, but check can't hurt
1543 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1544 continue; // skip the empty path values
1545 }
1546 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1547 if (file_exists(buffer)) {
1548 break;
1549 }
1550 }
1551 // release the storage
1552 for (int i = 0 ; i < n ; i++) {
1553 if (pelements[i] != NULL) {
1554 FREE_C_HEAP_ARRAY(char, pelements[i]);
1555 }
1556 }
1557 if (pelements != NULL) {
1558 FREE_C_HEAP_ARRAY(char*, pelements);
1559 }
1560 } else {
1561 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1562 }
1563 }
1564
1565 const char* os::get_current_directory(char *buf, int buflen) {
1566 return getcwd(buf, buflen);
1567 }
1568
1569 // check if addr is inside libjvm[_g].so
1570 bool os::address_is_in_vm(address addr) {
1571 static address libjvm_base_addr;
1572 Dl_info dlinfo;
1573
1574 if (libjvm_base_addr == NULL) {
1575 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo);
1576 libjvm_base_addr = (address)dlinfo.dli_fbase;
1577 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1578 }
1579
1580 if (dladdr((void *)addr, &dlinfo)) {
1581 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1582 }
1583
1584 return false;
1585 }
1586
1587 bool os::dll_address_to_function_name(address addr, char *buf,
1588 int buflen, int *offset) {
1589 Dl_info dlinfo;
1590
1591 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) {
1592 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1593 if (offset) *offset = addr - (address)dlinfo.dli_saddr;
1594 return true;
1595 } else {
1596 if (buf) buf[0] = '\0';
1597 if (offset) *offset = -1;
1598 return false;
1599 }
1600 }
1601
1602 struct _address_to_library_name {
1603 address addr; // input : memory address
1604 size_t buflen; // size of fname
1605 char* fname; // output: library name
1606 address base; // library base addr
1607 };
1608
1609 static int address_to_library_name_callback(struct dl_phdr_info *info,
1610 size_t size, void *data) {
1611 int i;
1612 bool found = false;
1613 address libbase = NULL;
1614 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1615
1616 // iterate through all loadable segments
1617 for (i = 0; i < info->dlpi_phnum; i++) {
1618 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1619 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1620 // base address of a library is the lowest address of its loaded
1621 // segments.
1622 if (libbase == NULL || libbase > segbase) {
1623 libbase = segbase;
1624 }
1625 // see if 'addr' is within current segment
1626 if (segbase <= d->addr &&
1627 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1628 found = true;
1629 }
1630 }
1631 }
1632
1633 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1634 // so dll_address_to_library_name() can fall through to use dladdr() which
1635 // can figure out executable name from argv[0].
1636 if (found && info->dlpi_name && info->dlpi_name[0]) {
1637 d->base = libbase;
1638 if (d->fname) {
1639 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1640 }
1641 return 1;
1642 }
1643 return 0;
1644 }
1645
1646 bool os::dll_address_to_library_name(address addr, char* buf,
1647 int buflen, int* offset) {
1648 Dl_info dlinfo;
1649 struct _address_to_library_name data;
1650
1651 // There is a bug in old glibc dladdr() implementation that it could resolve
1652 // to wrong library name if the .so file has a base address != NULL. Here
1653 // we iterate through the program headers of all loaded libraries to find
1654 // out which library 'addr' really belongs to. This workaround can be
1655 // removed once the minimum requirement for glibc is moved to 2.3.x.
1656 data.addr = addr;
1657 data.fname = buf;
1658 data.buflen = buflen;
1659 data.base = NULL;
1660 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1661
1662 if (rslt) {
1663 // buf already contains library name
1664 if (offset) *offset = addr - data.base;
1665 return true;
1666 } else if (dladdr((void*)addr, &dlinfo)){
1667 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1668 if (offset) *offset = addr - (address)dlinfo.dli_fbase;
1669 return true;
1670 } else {
1671 if (buf) buf[0] = '\0';
1672 if (offset) *offset = -1;
1673 return false;
1674 }
1675 }
1676
1677 // Loads .dll/.so and
1678 // in case of error it checks if .dll/.so was built for the
1679 // same architecture as Hotspot is running on
1680
1681 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1682 {
1683 void * result= ::dlopen(filename, RTLD_LAZY);
1684 if (result != NULL) {
1685 // Successful loading
1686 return result;
1687 }
1688
1689 Elf32_Ehdr elf_head;
1690
1691 // Read system error message into ebuf
1692 // It may or may not be overwritten below
1693 ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1694 ebuf[ebuflen-1]='\0';
1695 int diag_msg_max_length=ebuflen-strlen(ebuf);
1696 char* diag_msg_buf=ebuf+strlen(ebuf);
1697
1698 if (diag_msg_max_length==0) {
1699 // No more space in ebuf for additional diagnostics message
1700 return NULL;
1701 }
1702
1703
1704 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1705
1706 if (file_descriptor < 0) {
1707 // Can't open library, report dlerror() message
1708 return NULL;
1709 }
1710
1711 bool failed_to_read_elf_head=
1712 (sizeof(elf_head)!=
1713 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1714
1715 ::close(file_descriptor);
1716 if (failed_to_read_elf_head) {
1717 // file i/o error - report dlerror() msg
1718 return NULL;
1719 }
1720
1721 typedef struct {
1722 Elf32_Half code; // Actual value as defined in elf.h
1723 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1724 char elf_class; // 32 or 64 bit
1725 char endianess; // MSB or LSB
1726 char* name; // String representation
1727 } arch_t;
1728
1729 #ifndef EM_486
1730 #define EM_486 6 /* Intel 80486 */
1731 #endif
1732
1733 static const arch_t arch_array[]={
1734 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1735 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1736 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1737 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1738 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1739 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1740 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1741 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1742 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}
1743 };
1744
1745 #if (defined IA32)
1746 static Elf32_Half running_arch_code=EM_386;
1747 #elif (defined AMD64)
1748 static Elf32_Half running_arch_code=EM_X86_64;
1749 #elif (defined IA64)
1750 static Elf32_Half running_arch_code=EM_IA_64;
1751 #elif (defined __sparc) && (defined _LP64)
1752 static Elf32_Half running_arch_code=EM_SPARCV9;
1753 #elif (defined __sparc) && (!defined _LP64)
1754 static Elf32_Half running_arch_code=EM_SPARC;
1755 #elif (defined __powerpc64__)
1756 static Elf32_Half running_arch_code=EM_PPC64;
1757 #elif (defined __powerpc__)
1758 static Elf32_Half running_arch_code=EM_PPC;
1759 #else
1760 #error Method os::dll_load requires that one of following is defined:\
1761 IA32, AMD64, IA64, __sparc, __powerpc__
1762 #endif
1763
1764 // Identify compatability class for VM's architecture and library's architecture
1765 // Obtain string descriptions for architectures
1766
1767 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1768 int running_arch_index=-1;
1769
1770 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
1771 if (running_arch_code == arch_array[i].code) {
1772 running_arch_index = i;
1773 }
1774 if (lib_arch.code == arch_array[i].code) {
1775 lib_arch.compat_class = arch_array[i].compat_class;
1776 lib_arch.name = arch_array[i].name;
1777 }
1778 }
1779
1780 assert(running_arch_index != -1,
1781 "Didn't find running architecture code (running_arch_code) in arch_array");
1782 if (running_arch_index == -1) {
1783 // Even though running architecture detection failed
1784 // we may still continue with reporting dlerror() message
1785 return NULL;
1786 }
1787
1788 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1789 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1790 return NULL;
1791 }
1792
1793 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1794 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1795 return NULL;
1796 }
1797
1798 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1799 if ( lib_arch.name!=NULL ) {
1800 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1801 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1802 lib_arch.name, arch_array[running_arch_index].name);
1803 } else {
1804 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1805 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1806 lib_arch.code,
1807 arch_array[running_arch_index].name);
1808 }
1809 }
1810
1811 return NULL;
1812 }
1813
1814 /*
1815 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
1816 * chances are you might want to run the generated bits against glibc-2.0
1817 * libdl.so, so always use locking for any version of glibc.
1818 */
1819 void* os::dll_lookup(void* handle, const char* name) {
1820 pthread_mutex_lock(&dl_mutex);
1821 void* res = dlsym(handle, name);
1822 pthread_mutex_unlock(&dl_mutex);
1823 return res;
1824 }
1825
1826
1827 bool _print_ascii_file(const char* filename, outputStream* st) {
1828 int fd = open(filename, O_RDONLY);
1829 if (fd == -1) {
1830 return false;
1831 }
1832
1833 char buf[32];
1834 int bytes;
1835 while ((bytes = read(fd, buf, sizeof(buf))) > 0) {
1836 st->print_raw(buf, bytes);
1837 }
1838
1839 close(fd);
1840
1841 return true;
1842 }
1843
1844 void os::print_dll_info(outputStream *st) {
1845 st->print_cr("Dynamic libraries:");
1846
1847 char fname[32];
1848 pid_t pid = os::Linux::gettid();
1849
1850 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
1851
1852 if (!_print_ascii_file(fname, st)) {
1853 st->print("Can not get library information for pid = %d\n", pid);
1854 }
1855 }
1856
1857
1858 void os::print_os_info(outputStream* st) {
1859 st->print("OS:");
1860
1861 // Try to identify popular distros.
1862 // Most Linux distributions have /etc/XXX-release file, which contains
1863 // the OS version string. Some have more than one /etc/XXX-release file
1864 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.),
1865 // so the order is important.
1866 if (!_print_ascii_file("/etc/mandrake-release", st) &&
1867 !_print_ascii_file("/etc/sun-release", st) &&
1868 !_print_ascii_file("/etc/redhat-release", st) &&
1869 !_print_ascii_file("/etc/SuSE-release", st) &&
1870 !_print_ascii_file("/etc/turbolinux-release", st) &&
1871 !_print_ascii_file("/etc/gentoo-release", st) &&
1872 !_print_ascii_file("/etc/debian_version", st)) {
1873 st->print("Linux");
1874 }
1875 st->cr();
1876
1877 // kernel
1878 st->print("uname:");
1879 struct utsname name;
1880 uname(&name);
1881 st->print(name.sysname); st->print(" ");
1882 st->print(name.release); st->print(" ");
1883 st->print(name.version); st->print(" ");
1884 st->print(name.machine);
1885 st->cr();
1886
1887 // Print warning if unsafe chroot environment detected
1888 if (unsafe_chroot_detected) {
1889 st->print("WARNING!! ");
1890 st->print_cr(unstable_chroot_error);
1891 }
1892
1893 // libc, pthread
1894 st->print("libc:");
1895 st->print(os::Linux::glibc_version()); st->print(" ");
1896 st->print(os::Linux::libpthread_version()); st->print(" ");
1897 if (os::Linux::is_LinuxThreads()) {
1898 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
1899 }
1900 st->cr();
1901
1902 // rlimit
1903 st->print("rlimit:");
1904 struct rlimit rlim;
1905
1906 st->print(" STACK ");
1907 getrlimit(RLIMIT_STACK, &rlim);
1908 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
1909 else st->print("%uk", rlim.rlim_cur >> 10);
1910
1911 st->print(", CORE ");
1912 getrlimit(RLIMIT_CORE, &rlim);
1913 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
1914 else st->print("%uk", rlim.rlim_cur >> 10);
1915
1916 st->print(", NPROC ");
1917 getrlimit(RLIMIT_NPROC, &rlim);
1918 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
1919 else st->print("%d", rlim.rlim_cur);
1920
1921 st->print(", NOFILE ");
1922 getrlimit(RLIMIT_NOFILE, &rlim);
1923 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
1924 else st->print("%d", rlim.rlim_cur);
1925
1926 st->print(", AS ");
1927 getrlimit(RLIMIT_AS, &rlim);
1928 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
1929 else st->print("%uk", rlim.rlim_cur >> 10);
1930 st->cr();
1931
1932 // load average
1933 st->print("load average:");
1934 double loadavg[3];
1935 os::loadavg(loadavg, 3);
1936 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
1937 st->cr();
1938 }
1939
1940 void os::print_memory_info(outputStream* st) {
1941
1942 st->print("Memory:");
1943 st->print(" %dk page", os::vm_page_size()>>10);
1944
1945 // values in struct sysinfo are "unsigned long"
1946 struct sysinfo si;
1947 sysinfo(&si);
1948
1949 st->print(", physical " UINT64_FORMAT "k",
1950 os::physical_memory() >> 10);
1951 st->print("(" UINT64_FORMAT "k free)",
1952 os::available_memory() >> 10);
1953 st->print(", swap " UINT64_FORMAT "k",
1954 ((jlong)si.totalswap * si.mem_unit) >> 10);
1955 st->print("(" UINT64_FORMAT "k free)",
1956 ((jlong)si.freeswap * si.mem_unit) >> 10);
1957 st->cr();
1958 }
1959
1960 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific
1961 // but they're the same for all the linux arch that we support
1962 // and they're the same for solaris but there's no common place to put this.
1963 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR",
1964 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG",
1965 "ILL_COPROC", "ILL_BADSTK" };
1966
1967 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV",
1968 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES",
1969 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" };
1970
1971 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" };
1972
1973 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" };
1974
1975 void os::print_siginfo(outputStream* st, void* siginfo) {
1976 st->print("siginfo:");
1977
1978 const int buflen = 100;
1979 char buf[buflen];
1980 siginfo_t *si = (siginfo_t*)siginfo;
1981 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen));
1982 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) {
1983 st->print("si_errno=%s", buf);
1984 } else {
1985 st->print("si_errno=%d", si->si_errno);
1986 }
1987 const int c = si->si_code;
1988 assert(c > 0, "unexpected si_code");
1989 switch (si->si_signo) {
1990 case SIGILL:
1991 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]);
1992 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
1993 break;
1994 case SIGFPE:
1995 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]);
1996 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
1997 break;
1998 case SIGSEGV:
1999 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]);
2000 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2001 break;
2002 case SIGBUS:
2003 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]);
2004 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2005 break;
2006 default:
2007 st->print(", si_code=%d", si->si_code);
2008 // no si_addr
2009 }
2010
2011 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2012 UseSharedSpaces) {
2013 FileMapInfo* mapinfo = FileMapInfo::current_info();
2014 if (mapinfo->is_in_shared_space(si->si_addr)) {
2015 st->print("\n\nError accessing class data sharing archive." \
2016 " Mapped file inaccessible during execution, " \
2017 " possible disk/network problem.");
2018 }
2019 }
2020 st->cr();
2021 }
2022
2023
2024 static void print_signal_handler(outputStream* st, int sig,
2025 char* buf, size_t buflen);
2026
2027 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2028 st->print_cr("Signal Handlers:");
2029 print_signal_handler(st, SIGSEGV, buf, buflen);
2030 print_signal_handler(st, SIGBUS , buf, buflen);
2031 print_signal_handler(st, SIGFPE , buf, buflen);
2032 print_signal_handler(st, SIGPIPE, buf, buflen);
2033 print_signal_handler(st, SIGXFSZ, buf, buflen);
2034 print_signal_handler(st, SIGILL , buf, buflen);
2035 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2036 print_signal_handler(st, SR_signum, buf, buflen);
2037 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2038 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2039 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2040 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2041 }
2042
2043 static char saved_jvm_path[MAXPATHLEN] = {0};
2044
2045 // Find the full path to the current module, libjvm.so or libjvm_g.so
2046 void os::jvm_path(char *buf, jint len) {
2047 // Error checking.
2048 if (len < MAXPATHLEN) {
2049 assert(false, "must use a large-enough buffer");
2050 buf[0] = '\0';
2051 return;
2052 }
2053 // Lazy resolve the path to current module.
2054 if (saved_jvm_path[0] != 0) {
2055 strcpy(buf, saved_jvm_path);
2056 return;
2057 }
2058
2059 char dli_fname[MAXPATHLEN];
2060 bool ret = dll_address_to_library_name(
2061 CAST_FROM_FN_PTR(address, os::jvm_path),
2062 dli_fname, sizeof(dli_fname), NULL);
2063 assert(ret != 0, "cannot locate libjvm");
2064 if (realpath(dli_fname, buf) == NULL)
2065 return;
2066
2067 if (strcmp(Arguments::sun_java_launcher(), "gamma") == 0) {
2068 // Support for the gamma launcher. Typical value for buf is
2069 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2070 // the right place in the string, then assume we are installed in a JDK and
2071 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2072 // up the path so it looks like libjvm.so is installed there (append a
2073 // fake suffix hotspot/libjvm.so).
2074 const char *p = buf + strlen(buf) - 1;
2075 for (int count = 0; p > buf && count < 5; ++count) {
2076 for (--p; p > buf && *p != '/'; --p)
2077 /* empty */ ;
2078 }
2079
2080 if (strncmp(p, "/jre/lib/", 9) != 0) {
2081 // Look for JAVA_HOME in the environment.
2082 char* java_home_var = ::getenv("JAVA_HOME");
2083 if (java_home_var != NULL && java_home_var[0] != 0) {
2084 // Check the current module name "libjvm.so" or "libjvm_g.so".
2085 p = strrchr(buf, '/');
2086 assert(strstr(p, "/libjvm") == p, "invalid library name");
2087 p = strstr(p, "_g") ? "_g" : "";
2088
2089 if (realpath(java_home_var, buf) == NULL)
2090 return;
2091 sprintf(buf + strlen(buf), "/jre/lib/%s", cpu_arch);
2092 if (0 == access(buf, F_OK)) {
2093 // Use current module name "libjvm[_g].so" instead of
2094 // "libjvm"debug_only("_g")".so" since for fastdebug version
2095 // we should have "libjvm.so" but debug_only("_g") adds "_g"!
2096 // It is used when we are choosing the HPI library's name
2097 // "libhpi[_g].so" in hpi::initialize_get_interface().
2098 sprintf(buf + strlen(buf), "/hotspot/libjvm%s.so", p);
2099 } else {
2100 // Go back to path of .so
2101 if (realpath(dli_fname, buf) == NULL)
2102 return;
2103 }
2104 }
2105 }
2106 }
2107
2108 strcpy(saved_jvm_path, buf);
2109 }
2110
2111 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2112 // no prefix required, not even "_"
2113 }
2114
2115 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2116 // no suffix required
2117 }
2118
2119 ////////////////////////////////////////////////////////////////////////////////
2120 // sun.misc.Signal support
2121
2122 static volatile jint sigint_count = 0;
2123
2124 static void
2125 UserHandler(int sig, void *siginfo, void *context) {
2126 // 4511530 - sem_post is serialized and handled by the manager thread. When
2127 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2128 // don't want to flood the manager thread with sem_post requests.
2129 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2130 return;
2131
2132 // Ctrl-C is pressed during error reporting, likely because the error
2133 // handler fails to abort. Let VM die immediately.
2134 if (sig == SIGINT && is_error_reported()) {
2135 os::die();
2136 }
2137
2138 os::signal_notify(sig);
2139 }
2140
2141 void* os::user_handler() {
2142 return CAST_FROM_FN_PTR(void*, UserHandler);
2143 }
2144
2145 extern "C" {
2146 typedef void (*sa_handler_t)(int);
2147 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2148 }
2149
2150 void* os::signal(int signal_number, void* handler) {
2151 struct sigaction sigAct, oldSigAct;
2152
2153 sigfillset(&(sigAct.sa_mask));
2154 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2155 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2156
2157 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2158 // -1 means registration failed
2159 return (void *)-1;
2160 }
2161
2162 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2163 }
2164
2165 void os::signal_raise(int signal_number) {
2166 ::raise(signal_number);
2167 }
2168
2169 /*
2170 * The following code is moved from os.cpp for making this
2171 * code platform specific, which it is by its very nature.
2172 */
2173
2174 // Will be modified when max signal is changed to be dynamic
2175 int os::sigexitnum_pd() {
2176 return NSIG;
2177 }
2178
2179 // a counter for each possible signal value
2180 static volatile jint pending_signals[NSIG+1] = { 0 };
2181
2182 // Linux(POSIX) specific hand shaking semaphore.
2183 static sem_t sig_sem;
2184
2185 void os::signal_init_pd() {
2186 // Initialize signal structures
2187 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2188
2189 // Initialize signal semaphore
2190 ::sem_init(&sig_sem, 0, 0);
2191 }
2192
2193 void os::signal_notify(int sig) {
2194 Atomic::inc(&pending_signals[sig]);
2195 ::sem_post(&sig_sem);
2196 }
2197
2198 static int check_pending_signals(bool wait) {
2199 Atomic::store(0, &sigint_count);
2200 for (;;) {
2201 for (int i = 0; i < NSIG + 1; i++) {
2202 jint n = pending_signals[i];
2203 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2204 return i;
2205 }
2206 }
2207 if (!wait) {
2208 return -1;
2209 }
2210 JavaThread *thread = JavaThread::current();
2211 ThreadBlockInVM tbivm(thread);
2212
2213 bool threadIsSuspended;
2214 do {
2215 thread->set_suspend_equivalent();
2216 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2217 ::sem_wait(&sig_sem);
2218
2219 // were we externally suspended while we were waiting?
2220 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2221 if (threadIsSuspended) {
2222 //
2223 // The semaphore has been incremented, but while we were waiting
2224 // another thread suspended us. We don't want to continue running
2225 // while suspended because that would surprise the thread that
2226 // suspended us.
2227 //
2228 ::sem_post(&sig_sem);
2229
2230 thread->java_suspend_self();
2231 }
2232 } while (threadIsSuspended);
2233 }
2234 }
2235
2236 int os::signal_lookup() {
2237 return check_pending_signals(false);
2238 }
2239
2240 int os::signal_wait() {
2241 return check_pending_signals(true);
2242 }
2243
2244 ////////////////////////////////////////////////////////////////////////////////
2245 // Virtual Memory
2246
2247 int os::vm_page_size() {
2248 // Seems redundant as all get out
2249 assert(os::Linux::page_size() != -1, "must call os::init");
2250 return os::Linux::page_size();
2251 }
2252
2253 // Solaris allocates memory by pages.
2254 int os::vm_allocation_granularity() {
2255 assert(os::Linux::page_size() != -1, "must call os::init");
2256 return os::Linux::page_size();
2257 }
2258
2259 // Rationale behind this function:
2260 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2261 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2262 // samples for JITted code. Here we create private executable mapping over the code cache
2263 // and then we can use standard (well, almost, as mapping can change) way to provide
2264 // info for the reporting script by storing timestamp and location of symbol
2265 void linux_wrap_code(char* base, size_t size) {
2266 static volatile jint cnt = 0;
2267
2268 if (!UseOprofile) {
2269 return;
2270 }
2271
2272 char buf[40];
2273 int num = Atomic::add(1, &cnt);
2274
2275 sprintf(buf, "/tmp/hs-vm-%d-%d", os::current_process_id(), num);
2276 unlink(buf);
2277
2278 int fd = open(buf, O_CREAT | O_RDWR, S_IRWXU);
2279
2280 if (fd != -1) {
2281 off_t rv = lseek(fd, size-2, SEEK_SET);
2282 if (rv != (off_t)-1) {
2283 if (write(fd, "", 1) == 1) {
2284 mmap(base, size,
2285 PROT_READ|PROT_WRITE|PROT_EXEC,
2286 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2287 }
2288 }
2289 close(fd);
2290 unlink(buf);
2291 }
2292 }
2293
2294 // NOTE: Linux kernel does not really reserve the pages for us.
2295 // All it does is to check if there are enough free pages
2296 // left at the time of mmap(). This could be a potential
2297 // problem.
2298 bool os::commit_memory(char* addr, size_t size) {
2299 uintptr_t res = (uintptr_t) ::mmap(addr, size,
2300 PROT_READ|PROT_WRITE|PROT_EXEC,
2301 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2302 return res != (uintptr_t) MAP_FAILED;
2303 }
2304
2305 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint) {
2306 return commit_memory(addr, size);
2307 }
2308
2309 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { }
2310
2311 void os::free_memory(char *addr, size_t bytes) {
2312 uncommit_memory(addr, bytes);
2313 }
2314
2315 void os::numa_make_global(char *addr, size_t bytes) {
2316 Linux::numa_interleave_memory(addr, bytes);
2317 }
2318
2319 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2320 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2321 }
2322
2323 bool os::numa_topology_changed() { return false; }
2324
2325 size_t os::numa_get_groups_num() {
2326 int max_node = Linux::numa_max_node();
2327 return max_node > 0 ? max_node + 1 : 1;
2328 }
2329
2330 int os::numa_get_group_id() {
2331 int cpu_id = Linux::sched_getcpu();
2332 if (cpu_id != -1) {
2333 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2334 if (lgrp_id != -1) {
2335 return lgrp_id;
2336 }
2337 }
2338 return 0;
2339 }
2340
2341 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2342 for (size_t i = 0; i < size; i++) {
2343 ids[i] = i;
2344 }
2345 return size;
2346 }
2347
2348 bool os::get_page_info(char *start, page_info* info) {
2349 return false;
2350 }
2351
2352 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2353 return end;
2354 }
2355
2356 extern "C" void numa_warn(int number, char *where, ...) { }
2357 extern "C" void numa_error(char *where) { }
2358
2359 bool os::Linux::libnuma_init() {
2360 // sched_getcpu() should be in libc.
2361 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2362 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2363
2364 if (sched_getcpu() != -1) { // Does it work?
2365 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2366 if (handle != NULL) {
2367 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2368 dlsym(handle, "numa_node_to_cpus")));
2369 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2370 dlsym(handle, "numa_max_node")));
2371 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2372 dlsym(handle, "numa_available")));
2373 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2374 dlsym(handle, "numa_tonode_memory")));
2375 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2376 dlsym(handle, "numa_interleave_memory")));
2377
2378
2379 if (numa_available() != -1) {
2380 set_numa_all_nodes((unsigned long*)dlsym(handle, "numa_all_nodes"));
2381 // Create a cpu -> node mapping
2382 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true);
2383 rebuild_cpu_to_node_map();
2384 return true;
2385 }
2386 }
2387 }
2388 return false;
2389 }
2390
2391 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2392 // The table is later used in get_node_by_cpu().
2393 void os::Linux::rebuild_cpu_to_node_map() {
2394 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2395 // in libnuma (possible values are starting from 16,
2396 // and continuing up with every other power of 2, but less
2397 // than the maximum number of CPUs supported by kernel), and
2398 // is a subject to change (in libnuma version 2 the requirements
2399 // are more reasonable) we'll just hardcode the number they use
2400 // in the library.
2401 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2402
2403 size_t cpu_num = os::active_processor_count();
2404 size_t cpu_map_size = NCPUS / BitsPerCLong;
2405 size_t cpu_map_valid_size =
2406 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2407
2408 cpu_to_node()->clear();
2409 cpu_to_node()->at_grow(cpu_num - 1);
2410 size_t node_num = numa_get_groups_num();
2411
2412 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size);
2413 for (size_t i = 0; i < node_num; i++) {
2414 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2415 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2416 if (cpu_map[j] != 0) {
2417 for (size_t k = 0; k < BitsPerCLong; k++) {
2418 if (cpu_map[j] & (1UL << k)) {
2419 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2420 }
2421 }
2422 }
2423 }
2424 }
2425 }
2426 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2427 }
2428
2429 int os::Linux::get_node_by_cpu(int cpu_id) {
2430 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2431 return cpu_to_node()->at(cpu_id);
2432 }
2433 return -1;
2434 }
2435
2436 GrowableArray<int>* os::Linux::_cpu_to_node;
2437 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2438 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2439 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2440 os::Linux::numa_available_func_t os::Linux::_numa_available;
2441 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2442 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2443 unsigned long* os::Linux::_numa_all_nodes;
2444
2445 bool os::uncommit_memory(char* addr, size_t size) {
2446 return ::mmap(addr, size,
2447 PROT_READ|PROT_WRITE|PROT_EXEC,
2448 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0)
2449 != MAP_FAILED;
2450 }
2451
2452 static address _highest_vm_reserved_address = NULL;
2453
2454 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
2455 // at 'requested_addr'. If there are existing memory mappings at the same
2456 // location, however, they will be overwritten. If 'fixed' is false,
2457 // 'requested_addr' is only treated as a hint, the return value may or
2458 // may not start from the requested address. Unlike Linux mmap(), this
2459 // function returns NULL to indicate failure.
2460 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
2461 char * addr;
2462 int flags;
2463
2464 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
2465 if (fixed) {
2466 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
2467 flags |= MAP_FIXED;
2468 }
2469
2470 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE|PROT_EXEC,
2471 flags, -1, 0);
2472
2473 if (addr != MAP_FAILED) {
2474 // anon_mmap() should only get called during VM initialization,
2475 // don't need lock (actually we can skip locking even it can be called
2476 // from multiple threads, because _highest_vm_reserved_address is just a
2477 // hint about the upper limit of non-stack memory regions.)
2478 if ((address)addr + bytes > _highest_vm_reserved_address) {
2479 _highest_vm_reserved_address = (address)addr + bytes;
2480 }
2481 }
2482
2483 return addr == MAP_FAILED ? NULL : addr;
2484 }
2485
2486 // Don't update _highest_vm_reserved_address, because there might be memory
2487 // regions above addr + size. If so, releasing a memory region only creates
2488 // a hole in the address space, it doesn't help prevent heap-stack collision.
2489 //
2490 static int anon_munmap(char * addr, size_t size) {
2491 return ::munmap(addr, size) == 0;
2492 }
2493
2494 char* os::reserve_memory(size_t bytes, char* requested_addr,
2495 size_t alignment_hint) {
2496 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
2497 }
2498
2499 bool os::release_memory(char* addr, size_t size) {
2500 return anon_munmap(addr, size);
2501 }
2502
2503 static address highest_vm_reserved_address() {
2504 return _highest_vm_reserved_address;
2505 }
2506
2507 static bool linux_mprotect(char* addr, size_t size, int prot) {
2508 // Linux wants the mprotect address argument to be page aligned.
2509 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
2510
2511 // According to SUSv3, mprotect() should only be used with mappings
2512 // established by mmap(), and mmap() always maps whole pages. Unaligned
2513 // 'addr' likely indicates problem in the VM (e.g. trying to change
2514 // protection of malloc'ed or statically allocated memory). Check the
2515 // caller if you hit this assert.
2516 assert(addr == bottom, "sanity check");
2517
2518 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
2519 return ::mprotect(bottom, size, prot) == 0;
2520 }
2521
2522 // Set protections specified
2523 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
2524 bool is_committed) {
2525 unsigned int p = 0;
2526 switch (prot) {
2527 case MEM_PROT_NONE: p = PROT_NONE; break;
2528 case MEM_PROT_READ: p = PROT_READ; break;
2529 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
2530 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2531 default:
2532 ShouldNotReachHere();
2533 }
2534 // is_committed is unused.
2535 return linux_mprotect(addr, bytes, p);
2536 }
2537
2538 bool os::guard_memory(char* addr, size_t size) {
2539 return linux_mprotect(addr, size, PROT_NONE);
2540 }
2541
2542 bool os::unguard_memory(char* addr, size_t size) {
2543 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
2544 }
2545
2546 // Large page support
2547
2548 static size_t _large_page_size = 0;
2549
2550 bool os::large_page_init() {
2551 if (!UseLargePages) return false;
2552
2553 if (LargePageSizeInBytes) {
2554 _large_page_size = LargePageSizeInBytes;
2555 } else {
2556 // large_page_size on Linux is used to round up heap size. x86 uses either
2557 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
2558 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
2559 // page as large as 256M.
2560 //
2561 // Here we try to figure out page size by parsing /proc/meminfo and looking
2562 // for a line with the following format:
2563 // Hugepagesize: 2048 kB
2564 //
2565 // If we can't determine the value (e.g. /proc is not mounted, or the text
2566 // format has been changed), we'll use the largest page size supported by
2567 // the processor.
2568
2569 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M);
2570
2571 FILE *fp = fopen("/proc/meminfo", "r");
2572 if (fp) {
2573 while (!feof(fp)) {
2574 int x = 0;
2575 char buf[16];
2576 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
2577 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
2578 _large_page_size = x * K;
2579 break;
2580 }
2581 } else {
2582 // skip to next line
2583 for (;;) {
2584 int ch = fgetc(fp);
2585 if (ch == EOF || ch == (int)'\n') break;
2586 }
2587 }
2588 }
2589 fclose(fp);
2590 }
2591 }
2592
2593 const size_t default_page_size = (size_t)Linux::page_size();
2594 if (_large_page_size > default_page_size) {
2595 _page_sizes[0] = _large_page_size;
2596 _page_sizes[1] = default_page_size;
2597 _page_sizes[2] = 0;
2598 }
2599
2600 // Large page support is available on 2.6 or newer kernel, some vendors
2601 // (e.g. Redhat) have backported it to their 2.4 based distributions.
2602 // We optimistically assume the support is available. If later it turns out
2603 // not true, VM will automatically switch to use regular page size.
2604 return true;
2605 }
2606
2607 #ifndef SHM_HUGETLB
2608 #define SHM_HUGETLB 04000
2609 #endif
2610
2611 char* os::reserve_memory_special(size_t bytes) {
2612 assert(UseLargePages, "only for large pages");
2613
2614 key_t key = IPC_PRIVATE;
2615 char *addr;
2616
2617 bool warn_on_failure = UseLargePages &&
2618 (!FLAG_IS_DEFAULT(UseLargePages) ||
2619 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
2620 );
2621 char msg[128];
2622
2623 // Create a large shared memory region to attach to based on size.
2624 // Currently, size is the total size of the heap
2625 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
2626 if (shmid == -1) {
2627 // Possible reasons for shmget failure:
2628 // 1. shmmax is too small for Java heap.
2629 // > check shmmax value: cat /proc/sys/kernel/shmmax
2630 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
2631 // 2. not enough large page memory.
2632 // > check available large pages: cat /proc/meminfo
2633 // > increase amount of large pages:
2634 // echo new_value > /proc/sys/vm/nr_hugepages
2635 // Note 1: different Linux may use different name for this property,
2636 // e.g. on Redhat AS-3 it is "hugetlb_pool".
2637 // Note 2: it's possible there's enough physical memory available but
2638 // they are so fragmented after a long run that they can't
2639 // coalesce into large pages. Try to reserve large pages when
2640 // the system is still "fresh".
2641 if (warn_on_failure) {
2642 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
2643 warning(msg);
2644 }
2645 return NULL;
2646 }
2647
2648 // attach to the region
2649 addr = (char*)shmat(shmid, NULL, 0);
2650 int err = errno;
2651
2652 // Remove shmid. If shmat() is successful, the actual shared memory segment
2653 // will be deleted when it's detached by shmdt() or when the process
2654 // terminates. If shmat() is not successful this will remove the shared
2655 // segment immediately.
2656 shmctl(shmid, IPC_RMID, NULL);
2657
2658 if ((intptr_t)addr == -1) {
2659 if (warn_on_failure) {
2660 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
2661 warning(msg);
2662 }
2663 return NULL;
2664 }
2665
2666 return addr;
2667 }
2668
2669 bool os::release_memory_special(char* base, size_t bytes) {
2670 // detaching the SHM segment will also delete it, see reserve_memory_special()
2671 int rslt = shmdt(base);
2672 return rslt == 0;
2673 }
2674
2675 size_t os::large_page_size() {
2676 return _large_page_size;
2677 }
2678
2679 // Linux does not support anonymous mmap with large page memory. The only way
2680 // to reserve large page memory without file backing is through SysV shared
2681 // memory API. The entire memory region is committed and pinned upfront.
2682 // Hopefully this will change in the future...
2683 bool os::can_commit_large_page_memory() {
2684 return false;
2685 }
2686
2687 bool os::can_execute_large_page_memory() {
2688 return false;
2689 }
2690
2691 // Reserve memory at an arbitrary address, only if that area is
2692 // available (and not reserved for something else).
2693
2694 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
2695 const int max_tries = 10;
2696 char* base[max_tries];
2697 size_t size[max_tries];
2698 const size_t gap = 0x000000;
2699
2700 // Assert only that the size is a multiple of the page size, since
2701 // that's all that mmap requires, and since that's all we really know
2702 // about at this low abstraction level. If we need higher alignment,
2703 // we can either pass an alignment to this method or verify alignment
2704 // in one of the methods further up the call chain. See bug 5044738.
2705 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
2706
2707 // Repeatedly allocate blocks until the block is allocated at the
2708 // right spot. Give up after max_tries. Note that reserve_memory() will
2709 // automatically update _highest_vm_reserved_address if the call is
2710 // successful. The variable tracks the highest memory address every reserved
2711 // by JVM. It is used to detect heap-stack collision if running with
2712 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
2713 // space than needed, it could confuse the collision detecting code. To
2714 // solve the problem, save current _highest_vm_reserved_address and
2715 // calculate the correct value before return.
2716 address old_highest = _highest_vm_reserved_address;
2717
2718 // Linux mmap allows caller to pass an address as hint; give it a try first,
2719 // if kernel honors the hint then we can return immediately.
2720 char * addr = anon_mmap(requested_addr, bytes, false);
2721 if (addr == requested_addr) {
2722 return requested_addr;
2723 }
2724
2725 if (addr != NULL) {
2726 // mmap() is successful but it fails to reserve at the requested address
2727 anon_munmap(addr, bytes);
2728 }
2729
2730 int i;
2731 for (i = 0; i < max_tries; ++i) {
2732 base[i] = reserve_memory(bytes);
2733
2734 if (base[i] != NULL) {
2735 // Is this the block we wanted?
2736 if (base[i] == requested_addr) {
2737 size[i] = bytes;
2738 break;
2739 }
2740
2741 // Does this overlap the block we wanted? Give back the overlapped
2742 // parts and try again.
2743
2744 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
2745 if (top_overlap >= 0 && top_overlap < bytes) {
2746 unmap_memory(base[i], top_overlap);
2747 base[i] += top_overlap;
2748 size[i] = bytes - top_overlap;
2749 } else {
2750 size_t bottom_overlap = base[i] + bytes - requested_addr;
2751 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
2752 unmap_memory(requested_addr, bottom_overlap);
2753 size[i] = bytes - bottom_overlap;
2754 } else {
2755 size[i] = bytes;
2756 }
2757 }
2758 }
2759 }
2760
2761 // Give back the unused reserved pieces.
2762
2763 for (int j = 0; j < i; ++j) {
2764 if (base[j] != NULL) {
2765 unmap_memory(base[j], size[j]);
2766 }
2767 }
2768
2769 if (i < max_tries) {
2770 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
2771 return requested_addr;
2772 } else {
2773 _highest_vm_reserved_address = old_highest;
2774 return NULL;
2775 }
2776 }
2777
2778 size_t os::read(int fd, void *buf, unsigned int nBytes) {
2779 return ::read(fd, buf, nBytes);
2780 }
2781
2782 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
2783 // Solaris uses poll(), linux uses park().
2784 // Poll() is likely a better choice, assuming that Thread.interrupt()
2785 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
2786 // SIGSEGV, see 4355769.
2787
2788 const int NANOSECS_PER_MILLISECS = 1000000;
2789
2790 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
2791 assert(thread == Thread::current(), "thread consistency check");
2792
2793 ParkEvent * const slp = thread->_SleepEvent ;
2794 slp->reset() ;
2795 OrderAccess::fence() ;
2796
2797 if (interruptible) {
2798 jlong prevtime = javaTimeNanos();
2799
2800 for (;;) {
2801 if (os::is_interrupted(thread, true)) {
2802 return OS_INTRPT;
2803 }
2804
2805 jlong newtime = javaTimeNanos();
2806
2807 if (newtime - prevtime < 0) {
2808 // time moving backwards, should only happen if no monotonic clock
2809 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2810 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
2811 } else {
2812 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
2813 }
2814
2815 if(millis <= 0) {
2816 return OS_OK;
2817 }
2818
2819 prevtime = newtime;
2820
2821 {
2822 assert(thread->is_Java_thread(), "sanity check");
2823 JavaThread *jt = (JavaThread *) thread;
2824 ThreadBlockInVM tbivm(jt);
2825 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
2826
2827 jt->set_suspend_equivalent();
2828 // cleared by handle_special_suspend_equivalent_condition() or
2829 // java_suspend_self() via check_and_wait_while_suspended()
2830
2831 slp->park(millis);
2832
2833 // were we externally suspended while we were waiting?
2834 jt->check_and_wait_while_suspended();
2835 }
2836 }
2837 } else {
2838 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
2839 jlong prevtime = javaTimeNanos();
2840
2841 for (;;) {
2842 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
2843 // the 1st iteration ...
2844 jlong newtime = javaTimeNanos();
2845
2846 if (newtime - prevtime < 0) {
2847 // time moving backwards, should only happen if no monotonic clock
2848 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2849 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
2850 } else {
2851 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
2852 }
2853
2854 if(millis <= 0) break ;
2855
2856 prevtime = newtime;
2857 slp->park(millis);
2858 }
2859 return OS_OK ;
2860 }
2861 }
2862
2863 int os::naked_sleep() {
2864 // %% make the sleep time an integer flag. for now use 1 millisec.
2865 return os::sleep(Thread::current(), 1, false);
2866 }
2867
2868 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
2869 void os::infinite_sleep() {
2870 while (true) { // sleep forever ...
2871 ::sleep(100); // ... 100 seconds at a time
2872 }
2873 }
2874
2875 // Used to convert frequent JVM_Yield() to nops
2876 bool os::dont_yield() {
2877 return DontYieldALot;
2878 }
2879
2880 void os::yield() {
2881 sched_yield();
2882 }
2883
2884 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
2885
2886 void os::yield_all(int attempts) {
2887 // Yields to all threads, including threads with lower priorities
2888 // Threads on Linux are all with same priority. The Solaris style
2889 // os::yield_all() with nanosleep(1ms) is not necessary.
2890 sched_yield();
2891 }
2892
2893 // Called from the tight loops to possibly influence time-sharing heuristics
2894 void os::loop_breaker(int attempts) {
2895 os::yield_all(attempts);
2896 }
2897
2898 ////////////////////////////////////////////////////////////////////////////////
2899 // thread priority support
2900
2901 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
2902 // only supports dynamic priority, static priority must be zero. For real-time
2903 // applications, Linux supports SCHED_RR which allows static priority (1-99).
2904 // However, for large multi-threaded applications, SCHED_RR is not only slower
2905 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
2906 // of 5 runs - Sep 2005).
2907 //
2908 // The following code actually changes the niceness of kernel-thread/LWP. It
2909 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
2910 // not the entire user process, and user level threads are 1:1 mapped to kernel
2911 // threads. It has always been the case, but could change in the future. For
2912 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
2913 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
2914
2915 int os::java_to_os_priority[MaxPriority + 1] = {
2916 19, // 0 Entry should never be used
2917
2918 4, // 1 MinPriority
2919 3, // 2
2920 2, // 3
2921
2922 1, // 4
2923 0, // 5 NormPriority
2924 -1, // 6
2925
2926 -2, // 7
2927 -3, // 8
2928 -4, // 9 NearMaxPriority
2929
2930 -5 // 10 MaxPriority
2931 };
2932
2933 static int prio_init() {
2934 if (ThreadPriorityPolicy == 1) {
2935 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
2936 // if effective uid is not root. Perhaps, a more elegant way of doing
2937 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
2938 if (geteuid() != 0) {
2939 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
2940 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
2941 }
2942 ThreadPriorityPolicy = 0;
2943 }
2944 }
2945 return 0;
2946 }
2947
2948 OSReturn os::set_native_priority(Thread* thread, int newpri) {
2949 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
2950
2951 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
2952 return (ret == 0) ? OS_OK : OS_ERR;
2953 }
2954
2955 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
2956 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
2957 *priority_ptr = java_to_os_priority[NormPriority];
2958 return OS_OK;
2959 }
2960
2961 errno = 0;
2962 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
2963 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
2964 }
2965
2966 // Hint to the underlying OS that a task switch would not be good.
2967 // Void return because it's a hint and can fail.
2968 void os::hint_no_preempt() {}
2969
2970 ////////////////////////////////////////////////////////////////////////////////
2971 // suspend/resume support
2972
2973 // the low-level signal-based suspend/resume support is a remnant from the
2974 // old VM-suspension that used to be for java-suspension, safepoints etc,
2975 // within hotspot. Now there is a single use-case for this:
2976 // - calling get_thread_pc() on the VMThread by the flat-profiler task
2977 // that runs in the watcher thread.
2978 // The remaining code is greatly simplified from the more general suspension
2979 // code that used to be used.
2980 //
2981 // The protocol is quite simple:
2982 // - suspend:
2983 // - sends a signal to the target thread
2984 // - polls the suspend state of the osthread using a yield loop
2985 // - target thread signal handler (SR_handler) sets suspend state
2986 // and blocks in sigsuspend until continued
2987 // - resume:
2988 // - sets target osthread state to continue
2989 // - sends signal to end the sigsuspend loop in the SR_handler
2990 //
2991 // Note that the SR_lock plays no role in this suspend/resume protocol.
2992 //
2993
2994 static void resume_clear_context(OSThread *osthread) {
2995 osthread->set_ucontext(NULL);
2996 osthread->set_siginfo(NULL);
2997
2998 // notify the suspend action is completed, we have now resumed
2999 osthread->sr.clear_suspended();
3000 }
3001
3002 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3003 osthread->set_ucontext(context);
3004 osthread->set_siginfo(siginfo);
3005 }
3006
3007 //
3008 // Handler function invoked when a thread's execution is suspended or
3009 // resumed. We have to be careful that only async-safe functions are
3010 // called here (Note: most pthread functions are not async safe and
3011 // should be avoided.)
3012 //
3013 // Note: sigwait() is a more natural fit than sigsuspend() from an
3014 // interface point of view, but sigwait() prevents the signal hander
3015 // from being run. libpthread would get very confused by not having
3016 // its signal handlers run and prevents sigwait()'s use with the
3017 // mutex granting granting signal.
3018 //
3019 // Currently only ever called on the VMThread
3020 //
3021 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3022 // Save and restore errno to avoid confusing native code with EINTR
3023 // after sigsuspend.
3024 int old_errno = errno;
3025
3026 Thread* thread = Thread::current();
3027 OSThread* osthread = thread->osthread();
3028 assert(thread->is_VM_thread(), "Must be VMThread");
3029 // read current suspend action
3030 int action = osthread->sr.suspend_action();
3031 if (action == SR_SUSPEND) {
3032 suspend_save_context(osthread, siginfo, context);
3033
3034 // Notify the suspend action is about to be completed. do_suspend()
3035 // waits until SR_SUSPENDED is set and then returns. We will wait
3036 // here for a resume signal and that completes the suspend-other
3037 // action. do_suspend/do_resume is always called as a pair from
3038 // the same thread - so there are no races
3039
3040 // notify the caller
3041 osthread->sr.set_suspended();
3042
3043 sigset_t suspend_set; // signals for sigsuspend()
3044
3045 // get current set of blocked signals and unblock resume signal
3046 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3047 sigdelset(&suspend_set, SR_signum);
3048
3049 // wait here until we are resumed
3050 do {
3051 sigsuspend(&suspend_set);
3052 // ignore all returns until we get a resume signal
3053 } while (osthread->sr.suspend_action() != SR_CONTINUE);
3054
3055 resume_clear_context(osthread);
3056
3057 } else {
3058 assert(action == SR_CONTINUE, "unexpected sr action");
3059 // nothing special to do - just leave the handler
3060 }
3061
3062 errno = old_errno;
3063 }
3064
3065
3066 static int SR_initialize() {
3067 struct sigaction act;
3068 char *s;
3069 /* Get signal number to use for suspend/resume */
3070 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
3071 int sig = ::strtol(s, 0, 10);
3072 if (sig > 0 || sig < _NSIG) {
3073 SR_signum = sig;
3074 }
3075 }
3076
3077 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
3078 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
3079
3080 sigemptyset(&SR_sigset);
3081 sigaddset(&SR_sigset, SR_signum);
3082
3083 /* Set up signal handler for suspend/resume */
3084 act.sa_flags = SA_RESTART|SA_SIGINFO;
3085 act.sa_handler = (void (*)(int)) SR_handler;
3086
3087 // SR_signum is blocked by default.
3088 // 4528190 - We also need to block pthread restart signal (32 on all
3089 // supported Linux platforms). Note that LinuxThreads need to block
3090 // this signal for all threads to work properly. So we don't have
3091 // to use hard-coded signal number when setting up the mask.
3092 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
3093
3094 if (sigaction(SR_signum, &act, 0) == -1) {
3095 return -1;
3096 }
3097
3098 // Save signal flag
3099 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
3100 return 0;
3101 }
3102
3103 static int SR_finalize() {
3104 return 0;
3105 }
3106
3107
3108 // returns true on success and false on error - really an error is fatal
3109 // but this seems the normal response to library errors
3110 static bool do_suspend(OSThread* osthread) {
3111 // mark as suspended and send signal
3112 osthread->sr.set_suspend_action(SR_SUSPEND);
3113 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3114 assert_status(status == 0, status, "pthread_kill");
3115
3116 // check status and wait until notified of suspension
3117 if (status == 0) {
3118 for (int i = 0; !osthread->sr.is_suspended(); i++) {
3119 os::yield_all(i);
3120 }
3121 osthread->sr.set_suspend_action(SR_NONE);
3122 return true;
3123 }
3124 else {
3125 osthread->sr.set_suspend_action(SR_NONE);
3126 return false;
3127 }
3128 }
3129
3130 static void do_resume(OSThread* osthread) {
3131 assert(osthread->sr.is_suspended(), "thread should be suspended");
3132 osthread->sr.set_suspend_action(SR_CONTINUE);
3133
3134 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3135 assert_status(status == 0, status, "pthread_kill");
3136 // check status and wait unit notified of resumption
3137 if (status == 0) {
3138 for (int i = 0; osthread->sr.is_suspended(); i++) {
3139 os::yield_all(i);
3140 }
3141 }
3142 osthread->sr.set_suspend_action(SR_NONE);
3143 }
3144
3145 ////////////////////////////////////////////////////////////////////////////////
3146 // interrupt support
3147
3148 void os::interrupt(Thread* thread) {
3149 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3150 "possibility of dangling Thread pointer");
3151
3152 OSThread* osthread = thread->osthread();
3153
3154 if (!osthread->interrupted()) {
3155 osthread->set_interrupted(true);
3156 // More than one thread can get here with the same value of osthread,
3157 // resulting in multiple notifications. We do, however, want the store
3158 // to interrupted() to be visible to other threads before we execute unpark().
3159 OrderAccess::fence();
3160 ParkEvent * const slp = thread->_SleepEvent ;
3161 if (slp != NULL) slp->unpark() ;
3162 }
3163
3164 // For JSR166. Unpark even if interrupt status already was set
3165 if (thread->is_Java_thread())
3166 ((JavaThread*)thread)->parker()->unpark();
3167
3168 ParkEvent * ev = thread->_ParkEvent ;
3169 if (ev != NULL) ev->unpark() ;
3170
3171 }
3172
3173 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
3174 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3175 "possibility of dangling Thread pointer");
3176
3177 OSThread* osthread = thread->osthread();
3178
3179 bool interrupted = osthread->interrupted();
3180
3181 if (interrupted && clear_interrupted) {
3182 osthread->set_interrupted(false);
3183 // consider thread->_SleepEvent->reset() ... optional optimization
3184 }
3185
3186 return interrupted;
3187 }
3188
3189 ///////////////////////////////////////////////////////////////////////////////////
3190 // signal handling (except suspend/resume)
3191
3192 // This routine may be used by user applications as a "hook" to catch signals.
3193 // The user-defined signal handler must pass unrecognized signals to this
3194 // routine, and if it returns true (non-zero), then the signal handler must
3195 // return immediately. If the flag "abort_if_unrecognized" is true, then this
3196 // routine will never retun false (zero), but instead will execute a VM panic
3197 // routine kill the process.
3198 //
3199 // If this routine returns false, it is OK to call it again. This allows
3200 // the user-defined signal handler to perform checks either before or after
3201 // the VM performs its own checks. Naturally, the user code would be making
3202 // a serious error if it tried to handle an exception (such as a null check
3203 // or breakpoint) that the VM was generating for its own correct operation.
3204 //
3205 // This routine may recognize any of the following kinds of signals:
3206 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
3207 // It should be consulted by handlers for any of those signals.
3208 //
3209 // The caller of this routine must pass in the three arguments supplied
3210 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
3211 // field of the structure passed to sigaction(). This routine assumes that
3212 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
3213 //
3214 // Note that the VM will print warnings if it detects conflicting signal
3215 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
3216 //
3217 extern "C" int
3218 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
3219 void* ucontext, int abort_if_unrecognized);
3220
3221 void signalHandler(int sig, siginfo_t* info, void* uc) {
3222 assert(info != NULL && uc != NULL, "it must be old kernel");
3223 JVM_handle_linux_signal(sig, info, uc, true);
3224 }
3225
3226
3227 // This boolean allows users to forward their own non-matching signals
3228 // to JVM_handle_linux_signal, harmlessly.
3229 bool os::Linux::signal_handlers_are_installed = false;
3230
3231 // For signal-chaining
3232 struct sigaction os::Linux::sigact[MAXSIGNUM];
3233 unsigned int os::Linux::sigs = 0;
3234 bool os::Linux::libjsig_is_loaded = false;
3235 typedef struct sigaction *(*get_signal_t)(int);
3236 get_signal_t os::Linux::get_signal_action = NULL;
3237
3238 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
3239 struct sigaction *actp = NULL;
3240
3241 if (libjsig_is_loaded) {
3242 // Retrieve the old signal handler from libjsig
3243 actp = (*get_signal_action)(sig);
3244 }
3245 if (actp == NULL) {
3246 // Retrieve the preinstalled signal handler from jvm
3247 actp = get_preinstalled_handler(sig);
3248 }
3249
3250 return actp;
3251 }
3252
3253 static bool call_chained_handler(struct sigaction *actp, int sig,
3254 siginfo_t *siginfo, void *context) {
3255 // Call the old signal handler
3256 if (actp->sa_handler == SIG_DFL) {
3257 // It's more reasonable to let jvm treat it as an unexpected exception
3258 // instead of taking the default action.
3259 return false;
3260 } else if (actp->sa_handler != SIG_IGN) {
3261 if ((actp->sa_flags & SA_NODEFER) == 0) {
3262 // automaticlly block the signal
3263 sigaddset(&(actp->sa_mask), sig);
3264 }
3265
3266 sa_handler_t hand;
3267 sa_sigaction_t sa;
3268 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3269 // retrieve the chained handler
3270 if (siginfo_flag_set) {
3271 sa = actp->sa_sigaction;
3272 } else {
3273 hand = actp->sa_handler;
3274 }
3275
3276 if ((actp->sa_flags & SA_RESETHAND) != 0) {
3277 actp->sa_handler = SIG_DFL;
3278 }
3279
3280 // try to honor the signal mask
3281 sigset_t oset;
3282 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3283
3284 // call into the chained handler
3285 if (siginfo_flag_set) {
3286 (*sa)(sig, siginfo, context);
3287 } else {
3288 (*hand)(sig);
3289 }
3290
3291 // restore the signal mask
3292 pthread_sigmask(SIG_SETMASK, &oset, 0);
3293 }
3294 // Tell jvm's signal handler the signal is taken care of.
3295 return true;
3296 }
3297
3298 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3299 bool chained = false;
3300 // signal-chaining
3301 if (UseSignalChaining) {
3302 struct sigaction *actp = get_chained_signal_action(sig);
3303 if (actp != NULL) {
3304 chained = call_chained_handler(actp, sig, siginfo, context);
3305 }
3306 }
3307 return chained;
3308 }
3309
3310 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
3311 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
3312 return &sigact[sig];
3313 }
3314 return NULL;
3315 }
3316
3317 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3318 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3319 sigact[sig] = oldAct;
3320 sigs |= (unsigned int)1 << sig;
3321 }
3322
3323 // for diagnostic
3324 int os::Linux::sigflags[MAXSIGNUM];
3325
3326 int os::Linux::get_our_sigflags(int sig) {
3327 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3328 return sigflags[sig];
3329 }
3330
3331 void os::Linux::set_our_sigflags(int sig, int flags) {
3332 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3333 sigflags[sig] = flags;
3334 }
3335
3336 void os::Linux::set_signal_handler(int sig, bool set_installed) {
3337 // Check for overwrite.
3338 struct sigaction oldAct;
3339 sigaction(sig, (struct sigaction*)NULL, &oldAct);
3340
3341 void* oldhand = oldAct.sa_sigaction
3342 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3343 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3344 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3345 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3346 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
3347 if (AllowUserSignalHandlers || !set_installed) {
3348 // Do not overwrite; user takes responsibility to forward to us.
3349 return;
3350 } else if (UseSignalChaining) {
3351 // save the old handler in jvm
3352 save_preinstalled_handler(sig, oldAct);
3353 // libjsig also interposes the sigaction() call below and saves the
3354 // old sigaction on it own.
3355 } else {
3356 fatal2("Encountered unexpected pre-existing sigaction handler %#lx for signal %d.", (long)oldhand, sig);
3357 }
3358 }
3359
3360 struct sigaction sigAct;
3361 sigfillset(&(sigAct.sa_mask));
3362 sigAct.sa_handler = SIG_DFL;
3363 if (!set_installed) {
3364 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3365 } else {
3366 sigAct.sa_sigaction = signalHandler;
3367 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3368 }
3369 // Save flags, which are set by ours
3370 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3371 sigflags[sig] = sigAct.sa_flags;
3372
3373 int ret = sigaction(sig, &sigAct, &oldAct);
3374 assert(ret == 0, "check");
3375
3376 void* oldhand2 = oldAct.sa_sigaction
3377 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3378 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3379 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3380 }
3381
3382 // install signal handlers for signals that HotSpot needs to
3383 // handle in order to support Java-level exception handling.
3384
3385 void os::Linux::install_signal_handlers() {
3386 if (!signal_handlers_are_installed) {
3387 signal_handlers_are_installed = true;
3388
3389 // signal-chaining
3390 typedef void (*signal_setting_t)();
3391 signal_setting_t begin_signal_setting = NULL;
3392 signal_setting_t end_signal_setting = NULL;
3393 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3394 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3395 if (begin_signal_setting != NULL) {
3396 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3397 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3398 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3399 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3400 libjsig_is_loaded = true;
3401 assert(UseSignalChaining, "should enable signal-chaining");
3402 }
3403 if (libjsig_is_loaded) {
3404 // Tell libjsig jvm is setting signal handlers
3405 (*begin_signal_setting)();
3406 }
3407
3408 set_signal_handler(SIGSEGV, true);
3409 set_signal_handler(SIGPIPE, true);
3410 set_signal_handler(SIGBUS, true);
3411 set_signal_handler(SIGILL, true);
3412 set_signal_handler(SIGFPE, true);
3413 set_signal_handler(SIGXFSZ, true);
3414
3415 if (libjsig_is_loaded) {
3416 // Tell libjsig jvm finishes setting signal handlers
3417 (*end_signal_setting)();
3418 }
3419
3420 // We don't activate signal checker if libjsig is in place, we trust ourselves
3421 // and if UserSignalHandler is installed all bets are off
3422 if (CheckJNICalls) {
3423 if (libjsig_is_loaded) {
3424 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3425 check_signals = false;
3426 }
3427 if (AllowUserSignalHandlers) {
3428 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3429 check_signals = false;
3430 }
3431 }
3432 }
3433 }
3434
3435 // This is the fastest way to get thread cpu time on Linux.
3436 // Returns cpu time (user+sys) for any thread, not only for current.
3437 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
3438 // It might work on 2.6.10+ with a special kernel/glibc patch.
3439 // For reference, please, see IEEE Std 1003.1-2004:
3440 // http://www.unix.org/single_unix_specification
3441
3442 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
3443 struct timespec tp;
3444 int rc = os::Linux::clock_gettime(clockid, &tp);
3445 assert(rc == 0, "clock_gettime is expected to return 0 code");
3446
3447 return (tp.tv_sec * SEC_IN_NANOSECS) + tp.tv_nsec;
3448 }
3449
3450 /////
3451 // glibc on Linux platform uses non-documented flag
3452 // to indicate, that some special sort of signal
3453 // trampoline is used.
3454 // We will never set this flag, and we should
3455 // ignore this flag in our diagnostic
3456 #ifdef SIGNIFICANT_SIGNAL_MASK
3457 #undef SIGNIFICANT_SIGNAL_MASK
3458 #endif
3459 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
3460
3461 static const char* get_signal_handler_name(address handler,
3462 char* buf, int buflen) {
3463 int offset;
3464 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3465 if (found) {
3466 // skip directory names
3467 const char *p1, *p2;
3468 p1 = buf;
3469 size_t len = strlen(os::file_separator());
3470 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3471 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
3472 } else {
3473 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3474 }
3475 return buf;
3476 }
3477
3478 static void print_signal_handler(outputStream* st, int sig,
3479 char* buf, size_t buflen) {
3480 struct sigaction sa;
3481
3482 sigaction(sig, NULL, &sa);
3483
3484 // See comment for SIGNIFICANT_SIGNAL_MASK define
3485 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3486
3487 st->print("%s: ", os::exception_name(sig, buf, buflen));
3488
3489 address handler = (sa.sa_flags & SA_SIGINFO)
3490 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3491 : CAST_FROM_FN_PTR(address, sa.sa_handler);
3492
3493 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3494 st->print("SIG_DFL");
3495 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3496 st->print("SIG_IGN");
3497 } else {
3498 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3499 }
3500
3501 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask);
3502
3503 address rh = VMError::get_resetted_sighandler(sig);
3504 // May be, handler was resetted by VMError?
3505 if(rh != NULL) {
3506 handler = rh;
3507 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
3508 }
3509
3510 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags);
3511
3512 // Check: is it our handler?
3513 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
3514 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3515 // It is our signal handler
3516 // check for flags, reset system-used one!
3517 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
3518 st->print(
3519 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3520 os::Linux::get_our_sigflags(sig));
3521 }
3522 }
3523 st->cr();
3524 }
3525
3526
3527 #define DO_SIGNAL_CHECK(sig) \
3528 if (!sigismember(&check_signal_done, sig)) \
3529 os::Linux::check_signal_handler(sig)
3530
3531 // This method is a periodic task to check for misbehaving JNI applications
3532 // under CheckJNI, we can add any periodic checks here
3533
3534 void os::run_periodic_checks() {
3535
3536 if (check_signals == false) return;
3537
3538 // SEGV and BUS if overridden could potentially prevent
3539 // generation of hs*.log in the event of a crash, debugging
3540 // such a case can be very challenging, so we absolutely
3541 // check the following for a good measure:
3542 DO_SIGNAL_CHECK(SIGSEGV);
3543 DO_SIGNAL_CHECK(SIGILL);
3544 DO_SIGNAL_CHECK(SIGFPE);
3545 DO_SIGNAL_CHECK(SIGBUS);
3546 DO_SIGNAL_CHECK(SIGPIPE);
3547 DO_SIGNAL_CHECK(SIGXFSZ);
3548
3549
3550 // ReduceSignalUsage allows the user to override these handlers
3551 // see comments at the very top and jvm_solaris.h
3552 if (!ReduceSignalUsage) {
3553 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
3554 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
3555 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
3556 DO_SIGNAL_CHECK(BREAK_SIGNAL);
3557 }
3558
3559 DO_SIGNAL_CHECK(SR_signum);
3560 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
3561 }
3562
3563 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
3564
3565 static os_sigaction_t os_sigaction = NULL;
3566
3567 void os::Linux::check_signal_handler(int sig) {
3568 char buf[O_BUFLEN];
3569 address jvmHandler = NULL;
3570
3571
3572 struct sigaction act;
3573 if (os_sigaction == NULL) {
3574 // only trust the default sigaction, in case it has been interposed
3575 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
3576 if (os_sigaction == NULL) return;
3577 }
3578
3579 os_sigaction(sig, (struct sigaction*)NULL, &act);
3580
3581
3582 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3583
3584 address thisHandler = (act.sa_flags & SA_SIGINFO)
3585 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
3586 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
3587
3588
3589 switch(sig) {
3590 case SIGSEGV:
3591 case SIGBUS:
3592 case SIGFPE:
3593 case SIGPIPE:
3594 case SIGILL:
3595 case SIGXFSZ:
3596 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
3597 break;
3598
3599 case SHUTDOWN1_SIGNAL:
3600 case SHUTDOWN2_SIGNAL:
3601 case SHUTDOWN3_SIGNAL:
3602 case BREAK_SIGNAL:
3603 jvmHandler = (address)user_handler();
3604 break;
3605
3606 case INTERRUPT_SIGNAL:
3607 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
3608 break;
3609
3610 default:
3611 if (sig == SR_signum) {
3612 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
3613 } else {
3614 return;
3615 }
3616 break;
3617 }
3618
3619 if (thisHandler != jvmHandler) {
3620 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
3621 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
3622 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
3623 // No need to check this sig any longer
3624 sigaddset(&check_signal_done, sig);
3625 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
3626 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
3627 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
3628 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
3629 // No need to check this sig any longer
3630 sigaddset(&check_signal_done, sig);
3631 }
3632
3633 // Dump all the signal
3634 if (sigismember(&check_signal_done, sig)) {
3635 print_signal_handlers(tty, buf, O_BUFLEN);
3636 }
3637 }
3638
3639 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
3640
3641 extern bool signal_name(int signo, char* buf, size_t len);
3642
3643 const char* os::exception_name(int exception_code, char* buf, size_t size) {
3644 if (0 < exception_code && exception_code <= SIGRTMAX) {
3645 // signal
3646 if (!signal_name(exception_code, buf, size)) {
3647 jio_snprintf(buf, size, "SIG%d", exception_code);
3648 }
3649 return buf;
3650 } else {
3651 return NULL;
3652 }
3653 }
3654
3655 // this is called _before_ the most of global arguments have been parsed
3656 void os::init(void) {
3657 char dummy; /* used to get a guess on initial stack address */
3658 // first_hrtime = gethrtime();
3659
3660 // With LinuxThreads the JavaMain thread pid (primordial thread)
3661 // is different than the pid of the java launcher thread.
3662 // So, on Linux, the launcher thread pid is passed to the VM
3663 // via the sun.java.launcher.pid property.
3664 // Use this property instead of getpid() if it was correctly passed.
3665 // See bug 6351349.
3666 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
3667
3668 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
3669
3670 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
3671
3672 init_random(1234567);
3673
3674 ThreadCritical::initialize();
3675
3676 Linux::set_page_size(sysconf(_SC_PAGESIZE));
3677 if (Linux::page_size() == -1) {
3678 fatal1("os_linux.cpp: os::init: sysconf failed (%s)", strerror(errno));
3679 }
3680 init_page_sizes((size_t) Linux::page_size());
3681
3682 Linux::initialize_system_info();
3683
3684 // main_thread points to the aboriginal thread
3685 Linux::_main_thread = pthread_self();
3686
3687 Linux::clock_init();
3688 initial_time_count = os::elapsed_counter();
3689 pthread_mutex_init(&dl_mutex, NULL);
3690 }
3691
3692 // To install functions for atexit system call
3693 extern "C" {
3694 static void perfMemory_exit_helper() {
3695 perfMemory_exit();
3696 }
3697 }
3698
3699 // this is called _after_ the global arguments have been parsed
3700 jint os::init_2(void)
3701 {
3702 Linux::fast_thread_clock_init();
3703
3704 // Allocate a single page and mark it as readable for safepoint polling
3705 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
3706 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
3707
3708 os::set_polling_page( polling_page );
3709
3710 #ifndef PRODUCT
3711 if(Verbose && PrintMiscellaneous)
3712 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
3713 #endif
3714
3715 if (!UseMembar) {
3716 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
3717 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page");
3718 os::set_memory_serialize_page( mem_serialize_page );
3719
3720 #ifndef PRODUCT
3721 if(Verbose && PrintMiscellaneous)
3722 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
3723 #endif
3724 }
3725
3726 FLAG_SET_DEFAULT(UseLargePages, os::large_page_init());
3727
3728 // initialize suspend/resume support - must do this before signal_sets_init()
3729 if (SR_initialize() != 0) {
3730 perror("SR_initialize failed");
3731 return JNI_ERR;
3732 }
3733
3734 Linux::signal_sets_init();
3735 Linux::install_signal_handlers();
3736
3737 size_t threadStackSizeInBytes = ThreadStackSize * K;
3738 if (threadStackSizeInBytes != 0 &&
3739 threadStackSizeInBytes < Linux::min_stack_allowed) {
3740 tty->print_cr("\nThe stack size specified is too small, "
3741 "Specify at least %dk",
3742 Linux::min_stack_allowed / K);
3743 return JNI_ERR;
3744 }
3745
3746 // Make the stack size a multiple of the page size so that
3747 // the yellow/red zones can be guarded.
3748 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
3749 vm_page_size()));
3750
3751 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
3752
3753 Linux::libpthread_init();
3754 if (PrintMiscellaneous && (Verbose || WizardMode)) {
3755 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
3756 Linux::glibc_version(), Linux::libpthread_version(),
3757 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
3758 }
3759
3760 if (UseNUMA) {
3761 if (!Linux::libnuma_init()) {
3762 UseNUMA = false;
3763 } else {
3764 if ((Linux::numa_max_node() < 1)) {
3765 // There's only one node(they start from 0), disable NUMA.
3766 UseNUMA = false;
3767 }
3768 }
3769 if (!UseNUMA && ForceNUMA) {
3770 UseNUMA = true;
3771 }
3772 }
3773
3774 if (MaxFDLimit) {
3775 // set the number of file descriptors to max. print out error
3776 // if getrlimit/setrlimit fails but continue regardless.
3777 struct rlimit nbr_files;
3778 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
3779 if (status != 0) {
3780 if (PrintMiscellaneous && (Verbose || WizardMode))
3781 perror("os::init_2 getrlimit failed");
3782 } else {
3783 nbr_files.rlim_cur = nbr_files.rlim_max;
3784 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
3785 if (status != 0) {
3786 if (PrintMiscellaneous && (Verbose || WizardMode))
3787 perror("os::init_2 setrlimit failed");
3788 }
3789 }
3790 }
3791
3792 // Initialize lock used to serialize thread creation (see os::create_thread)
3793 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
3794
3795 // Initialize HPI.
3796 jint hpi_result = hpi::initialize();
3797 if (hpi_result != JNI_OK) {
3798 tty->print_cr("There was an error trying to initialize the HPI library.");
3799 return hpi_result;
3800 }
3801
3802 // at-exit methods are called in the reverse order of their registration.
3803 // atexit functions are called on return from main or as a result of a
3804 // call to exit(3C). There can be only 32 of these functions registered
3805 // and atexit() does not set errno.
3806
3807 if (PerfAllowAtExitRegistration) {
3808 // only register atexit functions if PerfAllowAtExitRegistration is set.
3809 // atexit functions can be delayed until process exit time, which
3810 // can be problematic for embedded VM situations. Embedded VMs should
3811 // call DestroyJavaVM() to assure that VM resources are released.
3812
3813 // note: perfMemory_exit_helper atexit function may be removed in
3814 // the future if the appropriate cleanup code can be added to the
3815 // VM_Exit VMOperation's doit method.
3816 if (atexit(perfMemory_exit_helper) != 0) {
3817 warning("os::init2 atexit(perfMemory_exit_helper) failed");
3818 }
3819 }
3820
3821 // initialize thread priority policy
3822 prio_init();
3823
3824 return JNI_OK;
3825 }
3826
3827 // Mark the polling page as unreadable
3828 void os::make_polling_page_unreadable(void) {
3829 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
3830 fatal("Could not disable polling page");
3831 };
3832
3833 // Mark the polling page as readable
3834 void os::make_polling_page_readable(void) {
3835 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
3836 fatal("Could not enable polling page");
3837 }
3838 };
3839
3840 int os::active_processor_count() {
3841 // Linux doesn't yet have a (official) notion of processor sets,
3842 // so just return the number of online processors.
3843 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
3844 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
3845 return online_cpus;
3846 }
3847
3848 bool os::distribute_processes(uint length, uint* distribution) {
3849 // Not yet implemented.
3850 return false;
3851 }
3852
3853 bool os::bind_to_processor(uint processor_id) {
3854 // Not yet implemented.
3855 return false;
3856 }
3857
3858 ///
3859
3860 // Suspends the target using the signal mechanism and then grabs the PC before
3861 // resuming the target. Used by the flat-profiler only
3862 ExtendedPC os::get_thread_pc(Thread* thread) {
3863 // Make sure that it is called by the watcher for the VMThread
3864 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
3865 assert(thread->is_VM_thread(), "Can only be called for VMThread");
3866
3867 ExtendedPC epc;
3868
3869 OSThread* osthread = thread->osthread();
3870 if (do_suspend(osthread)) {
3871 if (osthread->ucontext() != NULL) {
3872 epc = os::Linux::ucontext_get_pc(osthread->ucontext());
3873 } else {
3874 // NULL context is unexpected, double-check this is the VMThread
3875 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
3876 }
3877 do_resume(osthread);
3878 }
3879 // failure means pthread_kill failed for some reason - arguably this is
3880 // a fatal problem, but such problems are ignored elsewhere
3881
3882 return epc;
3883 }
3884
3885 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
3886 {
3887 if (is_NPTL()) {
3888 return pthread_cond_timedwait(_cond, _mutex, _abstime);
3889 } else {
3890 #ifndef IA64
3891 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
3892 // word back to default 64bit precision if condvar is signaled. Java
3893 // wants 53bit precision. Save and restore current value.
3894 int fpu = get_fpu_control_word();
3895 #endif // IA64
3896 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
3897 #ifndef IA64
3898 set_fpu_control_word(fpu);
3899 #endif // IA64
3900 return status;
3901 }
3902 }
3903
3904 ////////////////////////////////////////////////////////////////////////////////
3905 // debug support
3906
3907 #ifndef PRODUCT
3908 static address same_page(address x, address y) {
3909 int page_bits = -os::vm_page_size();
3910 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits))
3911 return x;
3912 else if (x > y)
3913 return (address)(intptr_t(y) | ~page_bits) + 1;
3914 else
3915 return (address)(intptr_t(y) & page_bits);
3916 }
3917
3918 bool os::find(address addr) {
3919 Dl_info dlinfo;
3920 memset(&dlinfo, 0, sizeof(dlinfo));
3921 if (dladdr(addr, &dlinfo)) {
3922 tty->print(PTR_FORMAT ": ", addr);
3923 if (dlinfo.dli_sname != NULL) {
3924 tty->print("%s+%#x", dlinfo.dli_sname,
3925 addr - (intptr_t)dlinfo.dli_saddr);
3926 } else if (dlinfo.dli_fname) {
3927 tty->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
3928 } else {
3929 tty->print("<absolute address>");
3930 }
3931 if (dlinfo.dli_fname) {
3932 tty->print(" in %s", dlinfo.dli_fname);
3933 }
3934 if (dlinfo.dli_fbase) {
3935 tty->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
3936 }
3937 tty->cr();
3938
3939 if (Verbose) {
3940 // decode some bytes around the PC
3941 address begin = same_page(addr-40, addr);
3942 address end = same_page(addr+40, addr);
3943 address lowest = (address) dlinfo.dli_sname;
3944 if (!lowest) lowest = (address) dlinfo.dli_fbase;
3945 if (begin < lowest) begin = lowest;
3946 Dl_info dlinfo2;
3947 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr
3948 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
3949 end = (address) dlinfo2.dli_saddr;
3950 Disassembler::decode(begin, end);
3951 }
3952 return true;
3953 }
3954 return false;
3955 }
3956
3957 #endif
3958
3959 ////////////////////////////////////////////////////////////////////////////////
3960 // misc
3961
3962 // This does not do anything on Linux. This is basically a hook for being
3963 // able to use structured exception handling (thread-local exception filters)
3964 // on, e.g., Win32.
3965 void
3966 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
3967 JavaCallArguments* args, Thread* thread) {
3968 f(value, method, args, thread);
3969 }
3970
3971 void os::print_statistics() {
3972 }
3973
3974 int os::message_box(const char* title, const char* message) {
3975 int i;
3976 fdStream err(defaultStream::error_fd());
3977 for (i = 0; i < 78; i++) err.print_raw("=");
3978 err.cr();
3979 err.print_raw_cr(title);
3980 for (i = 0; i < 78; i++) err.print_raw("-");
3981 err.cr();
3982 err.print_raw_cr(message);
3983 for (i = 0; i < 78; i++) err.print_raw("=");
3984 err.cr();
3985
3986 char buf[16];
3987 // Prevent process from exiting upon "read error" without consuming all CPU
3988 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
3989
3990 return buf[0] == 'y' || buf[0] == 'Y';
3991 }
3992
3993 int os::stat(const char *path, struct stat *sbuf) {
3994 char pathbuf[MAX_PATH];
3995 if (strlen(path) > MAX_PATH - 1) {
3996 errno = ENAMETOOLONG;
3997 return -1;
3998 }
3999 hpi::native_path(strcpy(pathbuf, path));
4000 return ::stat(pathbuf, sbuf);
4001 }
4002
4003 bool os::check_heap(bool force) {
4004 return true;
4005 }
4006
4007 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
4008 return ::vsnprintf(buf, count, format, args);
4009 }
4010
4011 // Is a (classpath) directory empty?
4012 bool os::dir_is_empty(const char* path) {
4013 DIR *dir = NULL;
4014 struct dirent *ptr;
4015
4016 dir = opendir(path);
4017 if (dir == NULL) return true;
4018
4019 /* Scan the directory */
4020 bool result = true;
4021 char buf[sizeof(struct dirent) + MAX_PATH];
4022 while (result && (ptr = ::readdir(dir)) != NULL) {
4023 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
4024 result = false;
4025 }
4026 }
4027 closedir(dir);
4028 return result;
4029 }
4030
4031 // create binary file, rewriting existing file if required
4032 int os::create_binary_file(const char* path, bool rewrite_existing) {
4033 int oflags = O_WRONLY | O_CREAT;
4034 if (!rewrite_existing) {
4035 oflags |= O_EXCL;
4036 }
4037 return ::open64(path, oflags, S_IREAD | S_IWRITE);
4038 }
4039
4040 // return current position of file pointer
4041 jlong os::current_file_offset(int fd) {
4042 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
4043 }
4044
4045 // move file pointer to the specified offset
4046 jlong os::seek_to_file_offset(int fd, jlong offset) {
4047 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
4048 }
4049
4050 // Map a block of memory.
4051 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
4052 char *addr, size_t bytes, bool read_only,
4053 bool allow_exec) {
4054 int prot;
4055 int flags;
4056
4057 if (read_only) {
4058 prot = PROT_READ;
4059 flags = MAP_SHARED;
4060 } else {
4061 prot = PROT_READ | PROT_WRITE;
4062 flags = MAP_PRIVATE;
4063 }
4064
4065 if (allow_exec) {
4066 prot |= PROT_EXEC;
4067 }
4068
4069 if (addr != NULL) {
4070 flags |= MAP_FIXED;
4071 }
4072
4073 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
4074 fd, file_offset);
4075 if (mapped_address == MAP_FAILED) {
4076 return NULL;
4077 }
4078 return mapped_address;
4079 }
4080
4081
4082 // Remap a block of memory.
4083 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
4084 char *addr, size_t bytes, bool read_only,
4085 bool allow_exec) {
4086 // same as map_memory() on this OS
4087 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
4088 allow_exec);
4089 }
4090
4091
4092 // Unmap a block of memory.
4093 bool os::unmap_memory(char* addr, size_t bytes) {
4094 return munmap(addr, bytes) == 0;
4095 }
4096
4097 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
4098
4099 static clockid_t thread_cpu_clockid(Thread* thread) {
4100 pthread_t tid = thread->osthread()->pthread_id();
4101 clockid_t clockid;
4102
4103 // Get thread clockid
4104 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
4105 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
4106 return clockid;
4107 }
4108
4109 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
4110 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
4111 // of a thread.
4112 //
4113 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
4114 // the fast estimate available on the platform.
4115
4116 jlong os::current_thread_cpu_time() {
4117 if (os::Linux::supports_fast_thread_cpu_time()) {
4118 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4119 } else {
4120 // return user + sys since the cost is the same
4121 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
4122 }
4123 }
4124
4125 jlong os::thread_cpu_time(Thread* thread) {
4126 // consistent with what current_thread_cpu_time() returns
4127 if (os::Linux::supports_fast_thread_cpu_time()) {
4128 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4129 } else {
4130 return slow_thread_cpu_time(thread, true /* user + sys */);
4131 }
4132 }
4133
4134 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
4135 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4136 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4137 } else {
4138 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
4139 }
4140 }
4141
4142 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4143 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4144 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4145 } else {
4146 return slow_thread_cpu_time(thread, user_sys_cpu_time);
4147 }
4148 }
4149
4150 //
4151 // -1 on error.
4152 //
4153
4154 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4155 static bool proc_pid_cpu_avail = true;
4156 static bool proc_task_unchecked = true;
4157 static const char *proc_stat_path = "/proc/%d/stat";
4158 pid_t tid = thread->osthread()->thread_id();
4159 int i;
4160 char *s;
4161 char stat[2048];
4162 int statlen;
4163 char proc_name[64];
4164 int count;
4165 long sys_time, user_time;
4166 char string[64];
4167 int idummy;
4168 long ldummy;
4169 FILE *fp;
4170
4171 // We first try accessing /proc/<pid>/cpu since this is faster to
4172 // process. If this file is not present (linux kernels 2.5 and above)
4173 // then we open /proc/<pid>/stat.
4174 if ( proc_pid_cpu_avail ) {
4175 sprintf(proc_name, "/proc/%d/cpu", tid);
4176 fp = fopen(proc_name, "r");
4177 if ( fp != NULL ) {
4178 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time);
4179 fclose(fp);
4180 if ( count != 3 ) return -1;
4181
4182 if (user_sys_cpu_time) {
4183 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4184 } else {
4185 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4186 }
4187 }
4188 else proc_pid_cpu_avail = false;
4189 }
4190
4191 // The /proc/<tid>/stat aggregates per-process usage on
4192 // new Linux kernels 2.6+ where NPTL is supported.
4193 // The /proc/self/task/<tid>/stat still has the per-thread usage.
4194 // See bug 6328462.
4195 // There can be no directory /proc/self/task on kernels 2.4 with NPTL
4196 // and possibly in some other cases, so we check its availability.
4197 if (proc_task_unchecked && os::Linux::is_NPTL()) {
4198 // This is executed only once
4199 proc_task_unchecked = false;
4200 fp = fopen("/proc/self/task", "r");
4201 if (fp != NULL) {
4202 proc_stat_path = "/proc/self/task/%d/stat";
4203 fclose(fp);
4204 }
4205 }
4206
4207 sprintf(proc_name, proc_stat_path, tid);
4208 fp = fopen(proc_name, "r");
4209 if ( fp == NULL ) return -1;
4210 statlen = fread(stat, 1, 2047, fp);
4211 stat[statlen] = '\0';
4212 fclose(fp);
4213
4214 // Skip pid and the command string. Note that we could be dealing with
4215 // weird command names, e.g. user could decide to rename java launcher
4216 // to "java 1.4.2 :)", then the stat file would look like
4217 // 1234 (java 1.4.2 :)) R ... ...
4218 // We don't really need to know the command string, just find the last
4219 // occurrence of ")" and then start parsing from there. See bug 4726580.
4220 s = strrchr(stat, ')');
4221 i = 0;
4222 if (s == NULL ) return -1;
4223
4224 // Skip blank chars
4225 do s++; while (isspace(*s));
4226
4227 count = sscanf(s,"%*c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
4228 &idummy, &idummy, &idummy, &idummy, &idummy,
4229 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
4230 &user_time, &sys_time);
4231 if ( count != 12 ) return -1;
4232 if (user_sys_cpu_time) {
4233 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4234 } else {
4235 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4236 }
4237 }
4238
4239 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4240 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4241 info_ptr->may_skip_backward = false; // elapsed time not wall time
4242 info_ptr->may_skip_forward = false; // elapsed time not wall time
4243 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4244 }
4245
4246 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4247 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4248 info_ptr->may_skip_backward = false; // elapsed time not wall time
4249 info_ptr->may_skip_forward = false; // elapsed time not wall time
4250 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4251 }
4252
4253 bool os::is_thread_cpu_time_supported() {
4254 return true;
4255 }
4256
4257 // System loadavg support. Returns -1 if load average cannot be obtained.
4258 // Linux doesn't yet have a (official) notion of processor sets,
4259 // so just return the system wide load average.
4260 int os::loadavg(double loadavg[], int nelem) {
4261 return ::getloadavg(loadavg, nelem);
4262 }
4263
4264 void os::pause() {
4265 char filename[MAX_PATH];
4266 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4267 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4268 } else {
4269 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4270 }
4271
4272 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4273 if (fd != -1) {
4274 struct stat buf;
4275 close(fd);
4276 while (::stat(filename, &buf) == 0) {
4277 (void)::poll(NULL, 0, 100);
4278 }
4279 } else {
4280 jio_fprintf(stderr,
4281 "Could not open pause file '%s', continuing immediately.\n", filename);
4282 }
4283 }
4284
4285 extern "C" {
4286
4287 /**
4288 * NOTE: the following code is to keep the green threads code
4289 * in the libjava.so happy. Once the green threads is removed,
4290 * these code will no longer be needed.
4291 */
4292 int
4293 jdk_waitpid(pid_t pid, int* status, int options) {
4294 return waitpid(pid, status, options);
4295 }
4296
4297 int
4298 fork1() {
4299 return fork();
4300 }
4301
4302 int
4303 jdk_sem_init(sem_t *sem, int pshared, unsigned int value) {
4304 return sem_init(sem, pshared, value);
4305 }
4306
4307 int
4308 jdk_sem_post(sem_t *sem) {
4309 return sem_post(sem);
4310 }
4311
4312 int
4313 jdk_sem_wait(sem_t *sem) {
4314 return sem_wait(sem);
4315 }
4316
4317 int
4318 jdk_pthread_sigmask(int how , const sigset_t* newmask, sigset_t* oldmask) {
4319 return pthread_sigmask(how , newmask, oldmask);
4320 }
4321
4322 }
4323
4324 // Refer to the comments in os_solaris.cpp park-unpark.
4325 //
4326 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
4327 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
4328 // For specifics regarding the bug see GLIBC BUGID 261237 :
4329 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
4330 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
4331 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
4332 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
4333 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
4334 // and monitorenter when we're using 1-0 locking. All those operations may result in
4335 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
4336 // of libpthread avoids the problem, but isn't practical.
4337 //
4338 // Possible remedies:
4339 //
4340 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
4341 // This is palliative and probabilistic, however. If the thread is preempted
4342 // between the call to compute_abstime() and pthread_cond_timedwait(), more
4343 // than the minimum period may have passed, and the abstime may be stale (in the
4344 // past) resultin in a hang. Using this technique reduces the odds of a hang
4345 // but the JVM is still vulnerable, particularly on heavily loaded systems.
4346 //
4347 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
4348 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
4349 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
4350 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
4351 // thread.
4352 //
4353 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
4354 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
4355 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
4356 // This also works well. In fact it avoids kernel-level scalability impediments
4357 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
4358 // timers in a graceful fashion.
4359 //
4360 // 4. When the abstime value is in the past it appears that control returns
4361 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
4362 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
4363 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
4364 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
4365 // It may be possible to avoid reinitialization by checking the return
4366 // value from pthread_cond_timedwait(). In addition to reinitializing the
4367 // condvar we must establish the invariant that cond_signal() is only called
4368 // within critical sections protected by the adjunct mutex. This prevents
4369 // cond_signal() from "seeing" a condvar that's in the midst of being
4370 // reinitialized or that is corrupt. Sadly, this invariant obviates the
4371 // desirable signal-after-unlock optimization that avoids futile context switching.
4372 //
4373 // I'm also concerned that some versions of NTPL might allocate an auxilliary
4374 // structure when a condvar is used or initialized. cond_destroy() would
4375 // release the helper structure. Our reinitialize-after-timedwait fix
4376 // put excessive stress on malloc/free and locks protecting the c-heap.
4377 //
4378 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
4379 // It may be possible to refine (4) by checking the kernel and NTPL verisons
4380 // and only enabling the work-around for vulnerable environments.
4381
4382 // utility to compute the abstime argument to timedwait:
4383 // millis is the relative timeout time
4384 // abstime will be the absolute timeout time
4385 // TODO: replace compute_abstime() with unpackTime()
4386
4387 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
4388 if (millis < 0) millis = 0;
4389 struct timeval now;
4390 int status = gettimeofday(&now, NULL);
4391 assert(status == 0, "gettimeofday");
4392 jlong seconds = millis / 1000;
4393 millis %= 1000;
4394 if (seconds > 50000000) { // see man cond_timedwait(3T)
4395 seconds = 50000000;
4396 }
4397 abstime->tv_sec = now.tv_sec + seconds;
4398 long usec = now.tv_usec + millis * 1000;
4399 if (usec >= 1000000) {
4400 abstime->tv_sec += 1;
4401 usec -= 1000000;
4402 }
4403 abstime->tv_nsec = usec * 1000;
4404 return abstime;
4405 }
4406
4407
4408 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
4409 // Conceptually TryPark() should be equivalent to park(0).
4410
4411 int os::PlatformEvent::TryPark() {
4412 for (;;) {
4413 const int v = _Event ;
4414 guarantee ((v == 0) || (v == 1), "invariant") ;
4415 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
4416 }
4417 }
4418
4419 void os::PlatformEvent::park() { // AKA "down()"
4420 // Invariant: Only the thread associated with the Event/PlatformEvent
4421 // may call park().
4422 // TODO: assert that _Assoc != NULL or _Assoc == Self
4423 int v ;
4424 for (;;) {
4425 v = _Event ;
4426 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
4427 }
4428 guarantee (v >= 0, "invariant") ;
4429 if (v == 0) {
4430 // Do this the hard way by blocking ...
4431 int status = pthread_mutex_lock(_mutex);
4432 assert_status(status == 0, status, "mutex_lock");
4433 guarantee (_nParked == 0, "invariant") ;
4434 ++ _nParked ;
4435 while (_Event < 0) {
4436 status = pthread_cond_wait(_cond, _mutex);
4437 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
4438 // Treat this the same as if the wait was interrupted
4439 if (status == ETIME) { status = EINTR; }
4440 assert_status(status == 0 || status == EINTR, status, "cond_wait");
4441 }
4442 -- _nParked ;
4443
4444 // In theory we could move the ST of 0 into _Event past the unlock(),
4445 // but then we'd need a MEMBAR after the ST.
4446 _Event = 0 ;
4447 status = pthread_mutex_unlock(_mutex);
4448 assert_status(status == 0, status, "mutex_unlock");
4449 }
4450 guarantee (_Event >= 0, "invariant") ;
4451 }
4452
4453 int os::PlatformEvent::park(jlong millis) {
4454 guarantee (_nParked == 0, "invariant") ;
4455
4456 int v ;
4457 for (;;) {
4458 v = _Event ;
4459 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
4460 }
4461 guarantee (v >= 0, "invariant") ;
4462 if (v != 0) return OS_OK ;
4463
4464 // We do this the hard way, by blocking the thread.
4465 // Consider enforcing a minimum timeout value.
4466 struct timespec abst;
4467 compute_abstime(&abst, millis);
4468
4469 int ret = OS_TIMEOUT;
4470 int status = pthread_mutex_lock(_mutex);
4471 assert_status(status == 0, status, "mutex_lock");
4472 guarantee (_nParked == 0, "invariant") ;
4473 ++_nParked ;
4474
4475 // Object.wait(timo) will return because of
4476 // (a) notification
4477 // (b) timeout
4478 // (c) thread.interrupt
4479 //
4480 // Thread.interrupt and object.notify{All} both call Event::set.
4481 // That is, we treat thread.interrupt as a special case of notification.
4482 // The underlying Solaris implementation, cond_timedwait, admits
4483 // spurious/premature wakeups, but the JLS/JVM spec prevents the
4484 // JVM from making those visible to Java code. As such, we must
4485 // filter out spurious wakeups. We assume all ETIME returns are valid.
4486 //
4487 // TODO: properly differentiate simultaneous notify+interrupt.
4488 // In that case, we should propagate the notify to another waiter.
4489
4490 while (_Event < 0) {
4491 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
4492 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
4493 pthread_cond_destroy (_cond);
4494 pthread_cond_init (_cond, NULL) ;
4495 }
4496 assert_status(status == 0 || status == EINTR ||
4497 status == ETIME || status == ETIMEDOUT,
4498 status, "cond_timedwait");
4499 if (!FilterSpuriousWakeups) break ; // previous semantics
4500 if (status == ETIME || status == ETIMEDOUT) break ;
4501 // We consume and ignore EINTR and spurious wakeups.
4502 }
4503 --_nParked ;
4504 if (_Event >= 0) {
4505 ret = OS_OK;
4506 }
4507 _Event = 0 ;
4508 status = pthread_mutex_unlock(_mutex);
4509 assert_status(status == 0, status, "mutex_unlock");
4510 assert (_nParked == 0, "invariant") ;
4511 return ret;
4512 }
4513
4514 void os::PlatformEvent::unpark() {
4515 int v, AnyWaiters ;
4516 for (;;) {
4517 v = _Event ;
4518 if (v > 0) {
4519 // The LD of _Event could have reordered or be satisfied
4520 // by a read-aside from this processor's write buffer.
4521 // To avoid problems execute a barrier and then
4522 // ratify the value.
4523 OrderAccess::fence() ;
4524 if (_Event == v) return ;
4525 continue ;
4526 }
4527 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ;
4528 }
4529 if (v < 0) {
4530 // Wait for the thread associated with the event to vacate
4531 int status = pthread_mutex_lock(_mutex);
4532 assert_status(status == 0, status, "mutex_lock");
4533 AnyWaiters = _nParked ;
4534 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ;
4535 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
4536 AnyWaiters = 0 ;
4537 pthread_cond_signal (_cond);
4538 }
4539 status = pthread_mutex_unlock(_mutex);
4540 assert_status(status == 0, status, "mutex_unlock");
4541 if (AnyWaiters != 0) {
4542 status = pthread_cond_signal(_cond);
4543 assert_status(status == 0, status, "cond_signal");
4544 }
4545 }
4546
4547 // Note that we signal() _after dropping the lock for "immortal" Events.
4548 // This is safe and avoids a common class of futile wakeups. In rare
4549 // circumstances this can cause a thread to return prematurely from
4550 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
4551 // simply re-test the condition and re-park itself.
4552 }
4553
4554
4555 // JSR166
4556 // -------------------------------------------------------
4557
4558 /*
4559 * The solaris and linux implementations of park/unpark are fairly
4560 * conservative for now, but can be improved. They currently use a
4561 * mutex/condvar pair, plus a a count.
4562 * Park decrements count if > 0, else does a condvar wait. Unpark
4563 * sets count to 1 and signals condvar. Only one thread ever waits
4564 * on the condvar. Contention seen when trying to park implies that someone
4565 * is unparking you, so don't wait. And spurious returns are fine, so there
4566 * is no need to track notifications.
4567 */
4568
4569
4570 #define NANOSECS_PER_SEC 1000000000
4571 #define NANOSECS_PER_MILLISEC 1000000
4572 #define MAX_SECS 100000000
4573 /*
4574 * This code is common to linux and solaris and will be moved to a
4575 * common place in dolphin.
4576 *
4577 * The passed in time value is either a relative time in nanoseconds
4578 * or an absolute time in milliseconds. Either way it has to be unpacked
4579 * into suitable seconds and nanoseconds components and stored in the
4580 * given timespec structure.
4581 * Given time is a 64-bit value and the time_t used in the timespec is only
4582 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
4583 * overflow if times way in the future are given. Further on Solaris versions
4584 * prior to 10 there is a restriction (see cond_timedwait) that the specified
4585 * number of seconds, in abstime, is less than current_time + 100,000,000.
4586 * As it will be 28 years before "now + 100000000" will overflow we can
4587 * ignore overflow and just impose a hard-limit on seconds using the value
4588 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
4589 * years from "now".
4590 */
4591
4592 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
4593 assert (time > 0, "convertTime");
4594
4595 struct timeval now;
4596 int status = gettimeofday(&now, NULL);
4597 assert(status == 0, "gettimeofday");
4598
4599 time_t max_secs = now.tv_sec + MAX_SECS;
4600
4601 if (isAbsolute) {
4602 jlong secs = time / 1000;
4603 if (secs > max_secs) {
4604 absTime->tv_sec = max_secs;
4605 }
4606 else {
4607 absTime->tv_sec = secs;
4608 }
4609 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
4610 }
4611 else {
4612 jlong secs = time / NANOSECS_PER_SEC;
4613 if (secs >= MAX_SECS) {
4614 absTime->tv_sec = max_secs;
4615 absTime->tv_nsec = 0;
4616 }
4617 else {
4618 absTime->tv_sec = now.tv_sec + secs;
4619 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
4620 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
4621 absTime->tv_nsec -= NANOSECS_PER_SEC;
4622 ++absTime->tv_sec; // note: this must be <= max_secs
4623 }
4624 }
4625 }
4626 assert(absTime->tv_sec >= 0, "tv_sec < 0");
4627 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
4628 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
4629 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
4630 }
4631
4632 void Parker::park(bool isAbsolute, jlong time) {
4633 // Optional fast-path check:
4634 // Return immediately if a permit is available.
4635 if (_counter > 0) {
4636 _counter = 0 ;
4637 return ;
4638 }
4639
4640 Thread* thread = Thread::current();
4641 assert(thread->is_Java_thread(), "Must be JavaThread");
4642 JavaThread *jt = (JavaThread *)thread;
4643
4644 // Optional optimization -- avoid state transitions if there's an interrupt pending.
4645 // Check interrupt before trying to wait
4646 if (Thread::is_interrupted(thread, false)) {
4647 return;
4648 }
4649
4650 // Next, demultiplex/decode time arguments
4651 timespec absTime;
4652 if (time < 0) { // don't wait at all
4653 return;
4654 }
4655 if (time > 0) {
4656 unpackTime(&absTime, isAbsolute, time);
4657 }
4658
4659
4660 // Enter safepoint region
4661 // Beware of deadlocks such as 6317397.
4662 // The per-thread Parker:: mutex is a classic leaf-lock.
4663 // In particular a thread must never block on the Threads_lock while
4664 // holding the Parker:: mutex. If safepoints are pending both the
4665 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
4666 ThreadBlockInVM tbivm(jt);
4667
4668 // Don't wait if cannot get lock since interference arises from
4669 // unblocking. Also. check interrupt before trying wait
4670 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
4671 return;
4672 }
4673
4674 int status ;
4675 if (_counter > 0) { // no wait needed
4676 _counter = 0;
4677 status = pthread_mutex_unlock(_mutex);
4678 assert (status == 0, "invariant") ;
4679 return;
4680 }
4681
4682 #ifdef ASSERT
4683 // Don't catch signals while blocked; let the running threads have the signals.
4684 // (This allows a debugger to break into the running thread.)
4685 sigset_t oldsigs;
4686 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
4687 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
4688 #endif
4689
4690 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
4691 jt->set_suspend_equivalent();
4692 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
4693
4694 if (time == 0) {
4695 status = pthread_cond_wait (_cond, _mutex) ;
4696 } else {
4697 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ;
4698 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
4699 pthread_cond_destroy (_cond) ;
4700 pthread_cond_init (_cond, NULL);
4701 }
4702 }
4703 assert_status(status == 0 || status == EINTR ||
4704 status == ETIME || status == ETIMEDOUT,
4705 status, "cond_timedwait");
4706
4707 #ifdef ASSERT
4708 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
4709 #endif
4710
4711 _counter = 0 ;
4712 status = pthread_mutex_unlock(_mutex) ;
4713 assert_status(status == 0, status, "invariant") ;
4714 // If externally suspended while waiting, re-suspend
4715 if (jt->handle_special_suspend_equivalent_condition()) {
4716 jt->java_suspend_self();
4717 }
4718
4719 }
4720
4721 void Parker::unpark() {
4722 int s, status ;
4723 status = pthread_mutex_lock(_mutex);
4724 assert (status == 0, "invariant") ;
4725 s = _counter;
4726 _counter = 1;
4727 if (s < 1) {
4728 if (WorkAroundNPTLTimedWaitHang) {
4729 status = pthread_cond_signal (_cond) ;
4730 assert (status == 0, "invariant") ;
4731 status = pthread_mutex_unlock(_mutex);
4732 assert (status == 0, "invariant") ;
4733 } else {
4734 status = pthread_mutex_unlock(_mutex);
4735 assert (status == 0, "invariant") ;
4736 status = pthread_cond_signal (_cond) ;
4737 assert (status == 0, "invariant") ;
4738 }
4739 } else {
4740 pthread_mutex_unlock(_mutex);
4741 assert (status == 0, "invariant") ;
4742 }
4743 }
4744
4745
4746 extern char** environ;
4747
4748 #ifndef __NR_fork
4749 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
4750 #endif
4751
4752 #ifndef __NR_execve
4753 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
4754 #endif
4755
4756 // Run the specified command in a separate process. Return its exit value,
4757 // or -1 on failure (e.g. can't fork a new process).
4758 // Unlike system(), this function can be called from signal handler. It
4759 // doesn't block SIGINT et al.
4760 int os::fork_and_exec(char* cmd) {
4761 const char * argv[4] = {"sh", "-c", cmd, NULL};
4762
4763 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
4764 // pthread_atfork handlers and reset pthread library. All we need is a
4765 // separate process to execve. Make a direct syscall to fork process.
4766 // On IA64 there's no fork syscall, we have to use fork() and hope for
4767 // the best...
4768 pid_t pid = NOT_IA64(syscall(__NR_fork);)
4769 IA64_ONLY(fork();)
4770
4771 if (pid < 0) {
4772 // fork failed
4773 return -1;
4774
4775 } else if (pid == 0) {
4776 // child process
4777
4778 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
4779 // first to kill every thread on the thread list. Because this list is
4780 // not reset by fork() (see notes above), execve() will instead kill
4781 // every thread in the parent process. We know this is the only thread
4782 // in the new process, so make a system call directly.
4783 // IA64 should use normal execve() from glibc to match the glibc fork()
4784 // above.
4785 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
4786 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
4787
4788 // execve failed
4789 _exit(-1);
4790
4791 } else {
4792 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
4793 // care about the actual exit code, for now.
4794
4795 int status;
4796
4797 // Wait for the child process to exit. This returns immediately if
4798 // the child has already exited. */
4799 while (waitpid(pid, &status, 0) < 0) {
4800 switch (errno) {
4801 case ECHILD: return 0;
4802 case EINTR: break;
4803 default: return -1;
4804 }
4805 }
4806
4807 if (WIFEXITED(status)) {
4808 // The child exited normally; get its exit code.
4809 return WEXITSTATUS(status);
4810 } else if (WIFSIGNALED(status)) {
4811 // The child exited because of a signal
4812 // The best value to return is 0x80 + signal number,
4813 // because that is what all Unix shells do, and because
4814 // it allows callers to distinguish between process exit and
4815 // process death by signal.
4816 return 0x80 + WTERMSIG(status);
4817 } else {
4818 // Unknown exit code; pass it through
4819 return status;
4820 }
4821 }
4822 }