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 # define __STDC_FORMAT_MACROS
26
27 // do not include precompiled header file
28 # include "incls/_os_linux.cpp.incl"
29
30 // put OS-includes here
31 # include <sys/types.h>
32 # include <sys/mman.h>
33 # include <pthread.h>
34 # include <signal.h>
35 # include <errno.h>
36 # include <dlfcn.h>
37 # include <stdio.h>
38 # include <unistd.h>
39 # include <sys/resource.h>
40 # include <pthread.h>
41 # include <sys/stat.h>
42 # include <sys/time.h>
43 # include <sys/times.h>
44 # include <sys/utsname.h>
45 # include <sys/socket.h>
46 # include <sys/wait.h>
47 # include <pwd.h>
48 # include <poll.h>
49 # include <semaphore.h>
50 # include <fcntl.h>
51 # include <string.h>
52 # include <syscall.h>
53 # include <sys/sysinfo.h>
54 # include <gnu/libc-version.h>
55 # include <sys/ipc.h>
56 # include <sys/shm.h>
57 # include <link.h>
58 # include <stdint.h>
59 # include <inttypes.h>
60
61 #define MAX_PATH (2 * K)
62
63 // for timer info max values which include all bits
64 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
65 #define SEC_IN_NANOSECS 1000000000LL
66
67 ////////////////////////////////////////////////////////////////////////////////
68 // global variables
69 julong os::Linux::_physical_memory = 0;
70
71 address os::Linux::_initial_thread_stack_bottom = NULL;
72 uintptr_t os::Linux::_initial_thread_stack_size = 0;
73
74 int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
75 int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
76 Mutex* os::Linux::_createThread_lock = NULL;
77 pthread_t os::Linux::_main_thread;
78 int os::Linux::_page_size = -1;
79 bool os::Linux::_is_floating_stack = false;
80 bool os::Linux::_is_NPTL = false;
81 bool os::Linux::_supports_fast_thread_cpu_time = false;
82 const char * os::Linux::_glibc_version = NULL;
83 const char * os::Linux::_libpthread_version = NULL;
84
85 static jlong initial_time_count=0;
86
87 static int clock_tics_per_sec = 100;
88
89 // For diagnostics to print a message once. see run_periodic_checks
90 static sigset_t check_signal_done;
91 static bool check_signals = true;;
92
93 static pid_t _initial_pid = 0;
94
95 /* Signal number used to suspend/resume a thread */
96
97 /* do not use any signal number less than SIGSEGV, see 4355769 */
98 static int SR_signum = SIGUSR2;
99 sigset_t SR_sigset;
100
101 /* Used to protect dlsym() calls */
102 static pthread_mutex_t dl_mutex;
103
104 ////////////////////////////////////////////////////////////////////////////////
105 // utility functions
106
107 static int SR_initialize();
108 static int SR_finalize();
109
110 julong os::available_memory() {
111 return Linux::available_memory();
112 }
113
114 julong os::Linux::available_memory() {
115 // values in struct sysinfo are "unsigned long"
116 struct sysinfo si;
117 sysinfo(&si);
118
119 return (julong)si.freeram * si.mem_unit;
120 }
121
122 julong os::physical_memory() {
123 return Linux::physical_memory();
124 }
125
126 julong os::allocatable_physical_memory(julong size) {
127 #ifdef _LP64
128 return size;
129 #else
130 julong result = MIN2(size, (julong)3800*M);
131 if (!is_allocatable(result)) {
132 // See comments under solaris for alignment considerations
133 julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
134 result = MIN2(size, reasonable_size);
135 }
136 return result;
137 #endif // _LP64
138 }
139
140 ////////////////////////////////////////////////////////////////////////////////
141 // environment support
142
143 bool os::getenv(const char* name, char* buf, int len) {
144 const char* val = ::getenv(name);
145 if (val != NULL && strlen(val) < (size_t)len) {
146 strcpy(buf, val);
147 return true;
148 }
149 if (len > 0) buf[0] = 0; // return a null string
150 return false;
151 }
152
153
154 // Return true if user is running as root.
155
156 bool os::have_special_privileges() {
157 static bool init = false;
158 static bool privileges = false;
159 if (!init) {
160 privileges = (getuid() != geteuid()) || (getgid() != getegid());
161 init = true;
162 }
163 return privileges;
164 }
165
166
167 #ifndef SYS_gettid
168 // i386: 224, ia64: 1105, amd64: 186, sparc 143
169 #ifdef __ia64__
170 #define SYS_gettid 1105
171 #elif __i386__
172 #define SYS_gettid 224
173 #elif __amd64__
174 #define SYS_gettid 186
175 #elif __sparc__
176 #define SYS_gettid 143
177 #else
178 #error define gettid for the arch
179 #endif
180 #endif
181
182 // Cpu architecture string
183 #if defined(ZERO)
184 static char cpu_arch[] = ZERO_LIBARCH;
185 #elif defined(IA64)
186 static char cpu_arch[] = "ia64";
187 #elif defined(IA32)
188 static char cpu_arch[] = "i386";
189 #elif defined(AMD64)
190 static char cpu_arch[] = "amd64";
191 #elif defined(SPARC)
192 # ifdef _LP64
193 static char cpu_arch[] = "sparcv9";
194 # else
195 static char cpu_arch[] = "sparc";
196 # endif
197 #else
198 #error Add appropriate cpu_arch setting
199 #endif
200
201
202 // pid_t gettid()
203 //
204 // Returns the kernel thread id of the currently running thread. Kernel
205 // thread id is used to access /proc.
206 //
207 // (Note that getpid() on LinuxThreads returns kernel thread id too; but
208 // on NPTL, it returns the same pid for all threads, as required by POSIX.)
209 //
210 pid_t os::Linux::gettid() {
211 int rslt = syscall(SYS_gettid);
212 if (rslt == -1) {
213 // old kernel, no NPTL support
214 return getpid();
215 } else {
216 return (pid_t)rslt;
217 }
218 }
219
220 // Most versions of linux have a bug where the number of processors are
221 // determined by looking at the /proc file system. In a chroot environment,
222 // the system call returns 1. This causes the VM to act as if it is
223 // a single processor and elide locking (see is_MP() call).
224 static bool unsafe_chroot_detected = false;
225 static const char *unstable_chroot_error = "/proc file system not found.\n"
226 "Java may be unstable running multithreaded in a chroot "
227 "environment on Linux when /proc filesystem is not mounted.";
228
229 void os::Linux::initialize_system_info() {
230 set_processor_count(sysconf(_SC_NPROCESSORS_CONF));
231 if (processor_count() == 1) {
232 pid_t pid = os::Linux::gettid();
233 char fname[32];
234 jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
235 FILE *fp = fopen(fname, "r");
236 if (fp == NULL) {
237 unsafe_chroot_detected = true;
238 } else {
239 fclose(fp);
240 }
241 }
242 _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
243 assert(processor_count() > 0, "linux error");
244 }
245
246 void os::init_system_properties_values() {
247 // char arch[12];
248 // sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
249
250 // The next steps are taken in the product version:
251 //
252 // Obtain the JAVA_HOME value from the location of libjvm[_g].so.
253 // This library should be located at:
254 // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so.
255 //
256 // If "/jre/lib/" appears at the right place in the path, then we
257 // assume libjvm[_g].so is installed in a JDK and we use this path.
258 //
259 // Otherwise exit with message: "Could not create the Java virtual machine."
260 //
261 // The following extra steps are taken in the debugging version:
262 //
263 // If "/jre/lib/" does NOT appear at the right place in the path
264 // instead of exit check for $JAVA_HOME environment variable.
265 //
266 // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
267 // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so
268 // it looks like libjvm[_g].so is installed there
269 // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so.
270 //
271 // Otherwise exit.
272 //
273 // Important note: if the location of libjvm.so changes this
274 // code needs to be changed accordingly.
275
276 // The next few definitions allow the code to be verbatim:
277 #define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n))
278 #define getenv(n) ::getenv(n)
279
280 /*
281 * See ld(1):
282 * The linker uses the following search paths to locate required
283 * shared libraries:
284 * 1: ...
285 * ...
286 * 7: The default directories, normally /lib and /usr/lib.
287 */
288 #if defined(AMD64) || defined(_LP64) && (defined(SPARC) || defined(PPC) || defined(S390))
289 #define DEFAULT_LIBPATH "/usr/lib64:/lib64:/lib:/usr/lib"
290 #else
291 #define DEFAULT_LIBPATH "/lib:/usr/lib"
292 #endif
293
294 #define EXTENSIONS_DIR "/lib/ext"
295 #define ENDORSED_DIR "/lib/endorsed"
296 #define REG_DIR "/usr/java/packages"
297
298 {
299 /* sysclasspath, java_home, dll_dir */
300 {
301 char *home_path;
302 char *dll_path;
303 char *pslash;
304 char buf[MAXPATHLEN];
305 os::jvm_path(buf, sizeof(buf));
306
307 // Found the full path to libjvm.so.
308 // Now cut the path to <java_home>/jre if we can.
309 *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
310 pslash = strrchr(buf, '/');
311 if (pslash != NULL)
312 *pslash = '\0'; /* get rid of /{client|server|hotspot} */
313 dll_path = malloc(strlen(buf) + 1);
314 if (dll_path == NULL)
315 return;
316 strcpy(dll_path, buf);
317 Arguments::set_dll_dir(dll_path);
318
319 if (pslash != NULL) {
320 pslash = strrchr(buf, '/');
321 if (pslash != NULL) {
322 *pslash = '\0'; /* get rid of /<arch> */
323 pslash = strrchr(buf, '/');
324 if (pslash != NULL)
325 *pslash = '\0'; /* get rid of /lib */
326 }
327 }
328
329 home_path = malloc(strlen(buf) + 1);
330 if (home_path == NULL)
331 return;
332 strcpy(home_path, buf);
333 Arguments::set_java_home(home_path);
334
335 if (!set_boot_path('/', ':'))
336 return;
337 }
338
339 /*
340 * Where to look for native libraries
341 *
342 * Note: Due to a legacy implementation, most of the library path
343 * is set in the launcher. This was to accomodate linking restrictions
344 * on legacy Linux implementations (which are no longer supported).
345 * Eventually, all the library path setting will be done here.
346 *
347 * However, to prevent the proliferation of improperly built native
348 * libraries, the new path component /usr/java/packages is added here.
349 * Eventually, all the library path setting will be done here.
350 */
351 {
352 char *ld_library_path;
353
354 /*
355 * Construct the invariant part of ld_library_path. Note that the
356 * space for the colon and the trailing null are provided by the
357 * nulls included by the sizeof operator (so actually we allocate
358 * a byte more than necessary).
359 */
360 ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
361 strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
362 sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
363
364 /*
365 * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
366 * should always exist (until the legacy problem cited above is
367 * addressed).
368 */
369 char *v = getenv("LD_LIBRARY_PATH");
370 if (v != NULL) {
371 char *t = ld_library_path;
372 /* That's +1 for the colon and +1 for the trailing '\0' */
373 ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
374 sprintf(ld_library_path, "%s:%s", v, t);
375 }
376 Arguments::set_library_path(ld_library_path);
377 }
378
379 /*
380 * Extensions directories.
381 *
382 * Note that the space for the colon and the trailing null are provided
383 * by the nulls included by the sizeof operator (so actually one byte more
384 * than necessary is allocated).
385 */
386 {
387 char *buf = malloc(strlen(Arguments::get_java_home()) +
388 sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
389 sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
390 Arguments::get_java_home());
391 Arguments::set_ext_dirs(buf);
392 }
393
394 /* Endorsed standards default directory. */
395 {
396 char * buf;
397 buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
398 sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
399 Arguments::set_endorsed_dirs(buf);
400 }
401 }
402
403 #undef malloc
404 #undef getenv
405 #undef EXTENSIONS_DIR
406 #undef ENDORSED_DIR
407
408 // Done
409 return;
410 }
411
412 ////////////////////////////////////////////////////////////////////////////////
413 // breakpoint support
414
415 void os::breakpoint() {
416 BREAKPOINT;
417 }
418
419 extern "C" void breakpoint() {
420 // use debugger to set breakpoint here
421 }
422
423 ////////////////////////////////////////////////////////////////////////////////
424 // signal support
425
426 debug_only(static bool signal_sets_initialized = false);
427 static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
428
429 bool os::Linux::is_sig_ignored(int sig) {
430 struct sigaction oact;
431 sigaction(sig, (struct sigaction*)NULL, &oact);
432 void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
433 : CAST_FROM_FN_PTR(void*, oact.sa_handler);
434 if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
435 return true;
436 else
437 return false;
438 }
439
440 void os::Linux::signal_sets_init() {
441 // Should also have an assertion stating we are still single-threaded.
442 assert(!signal_sets_initialized, "Already initialized");
443 // Fill in signals that are necessarily unblocked for all threads in
444 // the VM. Currently, we unblock the following signals:
445 // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
446 // by -Xrs (=ReduceSignalUsage));
447 // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
448 // other threads. The "ReduceSignalUsage" boolean tells us not to alter
449 // the dispositions or masks wrt these signals.
450 // Programs embedding the VM that want to use the above signals for their
451 // own purposes must, at this time, use the "-Xrs" option to prevent
452 // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
453 // (See bug 4345157, and other related bugs).
454 // In reality, though, unblocking these signals is really a nop, since
455 // these signals are not blocked by default.
456 sigemptyset(&unblocked_sigs);
457 sigemptyset(&allowdebug_blocked_sigs);
458 sigaddset(&unblocked_sigs, SIGILL);
459 sigaddset(&unblocked_sigs, SIGSEGV);
460 sigaddset(&unblocked_sigs, SIGBUS);
461 sigaddset(&unblocked_sigs, SIGFPE);
462 sigaddset(&unblocked_sigs, SR_signum);
463
464 if (!ReduceSignalUsage) {
465 if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
466 sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
467 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
468 }
469 if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
470 sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
471 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
472 }
473 if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
474 sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
475 sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
476 }
477 }
478 // Fill in signals that are blocked by all but the VM thread.
479 sigemptyset(&vm_sigs);
480 if (!ReduceSignalUsage)
481 sigaddset(&vm_sigs, BREAK_SIGNAL);
482 debug_only(signal_sets_initialized = true);
483
484 }
485
486 // These are signals that are unblocked while a thread is running Java.
487 // (For some reason, they get blocked by default.)
488 sigset_t* os::Linux::unblocked_signals() {
489 assert(signal_sets_initialized, "Not initialized");
490 return &unblocked_sigs;
491 }
492
493 // These are the signals that are blocked while a (non-VM) thread is
494 // running Java. Only the VM thread handles these signals.
495 sigset_t* os::Linux::vm_signals() {
496 assert(signal_sets_initialized, "Not initialized");
497 return &vm_sigs;
498 }
499
500 // These are signals that are blocked during cond_wait to allow debugger in
501 sigset_t* os::Linux::allowdebug_blocked_signals() {
502 assert(signal_sets_initialized, "Not initialized");
503 return &allowdebug_blocked_sigs;
504 }
505
506 void os::Linux::hotspot_sigmask(Thread* thread) {
507
508 //Save caller's signal mask before setting VM signal mask
509 sigset_t caller_sigmask;
510 pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
511
512 OSThread* osthread = thread->osthread();
513 osthread->set_caller_sigmask(caller_sigmask);
514
515 pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
516
517 if (!ReduceSignalUsage) {
518 if (thread->is_VM_thread()) {
519 // Only the VM thread handles BREAK_SIGNAL ...
520 pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
521 } else {
522 // ... all other threads block BREAK_SIGNAL
523 pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
524 }
525 }
526 }
527
528 //////////////////////////////////////////////////////////////////////////////
529 // detecting pthread library
530
531 void os::Linux::libpthread_init() {
532 // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
533 // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
534 // generic name for earlier versions.
535 // Define macros here so we can build HotSpot on old systems.
536 # ifndef _CS_GNU_LIBC_VERSION
537 # define _CS_GNU_LIBC_VERSION 2
538 # endif
539 # ifndef _CS_GNU_LIBPTHREAD_VERSION
540 # define _CS_GNU_LIBPTHREAD_VERSION 3
541 # endif
542
543 size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
544 if (n > 0) {
545 char *str = (char *)malloc(n);
546 confstr(_CS_GNU_LIBC_VERSION, str, n);
547 os::Linux::set_glibc_version(str);
548 } else {
549 // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
550 static char _gnu_libc_version[32];
551 jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
552 "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
553 os::Linux::set_glibc_version(_gnu_libc_version);
554 }
555
556 n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
557 if (n > 0) {
558 char *str = (char *)malloc(n);
559 confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
560 // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
561 // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
562 // is the case. LinuxThreads has a hard limit on max number of threads.
563 // So sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
564 // On the other hand, NPTL does not have such a limit, sysconf()
565 // will return -1 and errno is not changed. Check if it is really NPTL.
566 if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
567 strstr(str, "NPTL") &&
568 sysconf(_SC_THREAD_THREADS_MAX) > 0) {
569 free(str);
570 os::Linux::set_libpthread_version("linuxthreads");
571 } else {
572 os::Linux::set_libpthread_version(str);
573 }
574 } else {
575 // glibc before 2.3.2 only has LinuxThreads.
576 os::Linux::set_libpthread_version("linuxthreads");
577 }
578
579 if (strstr(libpthread_version(), "NPTL")) {
580 os::Linux::set_is_NPTL();
581 } else {
582 os::Linux::set_is_LinuxThreads();
583 }
584
585 // LinuxThreads have two flavors: floating-stack mode, which allows variable
586 // stack size; and fixed-stack mode. NPTL is always floating-stack.
587 if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
588 os::Linux::set_is_floating_stack();
589 }
590 }
591
592 /////////////////////////////////////////////////////////////////////////////
593 // thread stack
594
595 // Force Linux kernel to expand current thread stack. If "bottom" is close
596 // to the stack guard, caller should block all signals.
597 //
598 // MAP_GROWSDOWN:
599 // A special mmap() flag that is used to implement thread stacks. It tells
600 // kernel that the memory region should extend downwards when needed. This
601 // allows early versions of LinuxThreads to only mmap the first few pages
602 // when creating a new thread. Linux kernel will automatically expand thread
603 // stack as needed (on page faults).
604 //
605 // However, because the memory region of a MAP_GROWSDOWN stack can grow on
606 // demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
607 // region, it's hard to tell if the fault is due to a legitimate stack
608 // access or because of reading/writing non-exist memory (e.g. buffer
609 // overrun). As a rule, if the fault happens below current stack pointer,
610 // Linux kernel does not expand stack, instead a SIGSEGV is sent to the
611 // application (see Linux kernel fault.c).
612 //
613 // This Linux feature can cause SIGSEGV when VM bangs thread stack for
614 // stack overflow detection.
615 //
616 // Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
617 // not use this flag. However, the stack of initial thread is not created
618 // by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
619 // unlikely) that user code can create a thread with MAP_GROWSDOWN stack
620 // and then attach the thread to JVM.
621 //
622 // To get around the problem and allow stack banging on Linux, we need to
623 // manually expand thread stack after receiving the SIGSEGV.
624 //
625 // There are two ways to expand thread stack to address "bottom", we used
626 // both of them in JVM before 1.5:
627 // 1. adjust stack pointer first so that it is below "bottom", and then
628 // touch "bottom"
629 // 2. mmap() the page in question
630 //
631 // Now alternate signal stack is gone, it's harder to use 2. For instance,
632 // if current sp is already near the lower end of page 101, and we need to
633 // call mmap() to map page 100, it is possible that part of the mmap() frame
634 // will be placed in page 100. When page 100 is mapped, it is zero-filled.
635 // That will destroy the mmap() frame and cause VM to crash.
636 //
637 // The following code works by adjusting sp first, then accessing the "bottom"
638 // page to force a page fault. Linux kernel will then automatically expand the
639 // stack mapping.
640 //
641 // _expand_stack_to() assumes its frame size is less than page size, which
642 // should always be true if the function is not inlined.
643
644 #if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
645 #define NOINLINE
646 #else
647 #define NOINLINE __attribute__ ((noinline))
648 #endif
649
650 static void _expand_stack_to(address bottom) NOINLINE;
651
652 static void _expand_stack_to(address bottom) {
653 address sp;
654 size_t size;
655 volatile char *p;
656
657 // Adjust bottom to point to the largest address within the same page, it
658 // gives us a one-page buffer if alloca() allocates slightly more memory.
659 bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
660 bottom += os::Linux::page_size() - 1;
661
662 // sp might be slightly above current stack pointer; if that's the case, we
663 // will alloca() a little more space than necessary, which is OK. Don't use
664 // os::current_stack_pointer(), as its result can be slightly below current
665 // stack pointer, causing us to not alloca enough to reach "bottom".
666 sp = (address)&sp;
667
668 if (sp > bottom) {
669 size = sp - bottom;
670 p = (volatile char *)alloca(size);
671 assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
672 p[0] = '\0';
673 }
674 }
675
676 bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
677 assert(t!=NULL, "just checking");
678 assert(t->osthread()->expanding_stack(), "expand should be set");
679 assert(t->stack_base() != NULL, "stack_base was not initialized");
680
681 if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
682 sigset_t mask_all, old_sigset;
683 sigfillset(&mask_all);
684 pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
685 _expand_stack_to(addr);
686 pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
687 return true;
688 }
689 return false;
690 }
691
692 //////////////////////////////////////////////////////////////////////////////
693 // create new thread
694
695 static address highest_vm_reserved_address();
696
697 // check if it's safe to start a new thread
698 static bool _thread_safety_check(Thread* thread) {
699 if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
700 // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
701 // Heap is mmap'ed at lower end of memory space. Thread stacks are
702 // allocated (MAP_FIXED) from high address space. Every thread stack
703 // occupies a fixed size slot (usually 2Mbytes, but user can change
704 // it to other values if they rebuild LinuxThreads).
705 //
706 // Problem with MAP_FIXED is that mmap() can still succeed even part of
707 // the memory region has already been mmap'ed. That means if we have too
708 // many threads and/or very large heap, eventually thread stack will
709 // collide with heap.
710 //
711 // Here we try to prevent heap/stack collision by comparing current
712 // stack bottom with the highest address that has been mmap'ed by JVM
713 // plus a safety margin for memory maps created by native code.
714 //
715 // This feature can be disabled by setting ThreadSafetyMargin to 0
716 //
717 if (ThreadSafetyMargin > 0) {
718 address stack_bottom = os::current_stack_base() - os::current_stack_size();
719
720 // not safe if our stack extends below the safety margin
721 return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
722 } else {
723 return true;
724 }
725 } else {
726 // Floating stack LinuxThreads or NPTL:
727 // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
728 // there's not enough space left, pthread_create() will fail. If we come
729 // here, that means enough space has been reserved for stack.
730 return true;
731 }
732 }
733
734 // Thread start routine for all newly created threads
735 static void *java_start(Thread *thread) {
736 // Try to randomize the cache line index of hot stack frames.
737 // This helps when threads of the same stack traces evict each other's
738 // cache lines. The threads can be either from the same JVM instance, or
739 // from different JVM instances. The benefit is especially true for
740 // processors with hyperthreading technology.
741 static int counter = 0;
742 int pid = os::current_process_id();
743 alloca(((pid ^ counter++) & 7) * 128);
744
745 ThreadLocalStorage::set_thread(thread);
746
747 OSThread* osthread = thread->osthread();
748 Monitor* sync = osthread->startThread_lock();
749
750 // non floating stack LinuxThreads needs extra check, see above
751 if (!_thread_safety_check(thread)) {
752 // notify parent thread
753 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
754 osthread->set_state(ZOMBIE);
755 sync->notify_all();
756 return NULL;
757 }
758
759 // thread_id is kernel thread id (similar to Solaris LWP id)
760 osthread->set_thread_id(os::Linux::gettid());
761
762 if (UseNUMA) {
763 int lgrp_id = os::numa_get_group_id();
764 if (lgrp_id != -1) {
765 thread->set_lgrp_id(lgrp_id);
766 }
767 }
768 // initialize signal mask for this thread
769 os::Linux::hotspot_sigmask(thread);
770
771 // initialize floating point control register
772 os::Linux::init_thread_fpu_state();
773
774 // handshaking with parent thread
775 {
776 MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
777
778 // notify parent thread
779 osthread->set_state(INITIALIZED);
780 sync->notify_all();
781
782 // wait until os::start_thread()
783 while (osthread->get_state() == INITIALIZED) {
784 sync->wait(Mutex::_no_safepoint_check_flag);
785 }
786 }
787
788 // call one more level start routine
789 thread->run();
790
791 return 0;
792 }
793
794 bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
795 assert(thread->osthread() == NULL, "caller responsible");
796
797 // Allocate the OSThread object
798 OSThread* osthread = new OSThread(NULL, NULL);
799 if (osthread == NULL) {
800 return false;
801 }
802
803 // set the correct thread state
804 osthread->set_thread_type(thr_type);
805
806 // Initial state is ALLOCATED but not INITIALIZED
807 osthread->set_state(ALLOCATED);
808
809 thread->set_osthread(osthread);
810
811 // init thread attributes
812 pthread_attr_t attr;
813 pthread_attr_init(&attr);
814 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
815
816 // stack size
817 if (os::Linux::supports_variable_stack_size()) {
818 // calculate stack size if it's not specified by caller
819 if (stack_size == 0) {
820 stack_size = os::Linux::default_stack_size(thr_type);
821
822 switch (thr_type) {
823 case os::java_thread:
824 // Java threads use ThreadStackSize which default value can be changed with the flag -Xss
825 if (JavaThread::stack_size_at_create() > 0) stack_size = JavaThread::stack_size_at_create();
826 break;
827 case os::compiler_thread:
828 if (CompilerThreadStackSize > 0) {
829 stack_size = (size_t)(CompilerThreadStackSize * K);
830 break;
831 } // else fall through:
832 // use VMThreadStackSize if CompilerThreadStackSize is not defined
833 case os::vm_thread:
834 case os::pgc_thread:
835 case os::cgc_thread:
836 case os::watcher_thread:
837 if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
838 break;
839 }
840 }
841
842 stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
843 pthread_attr_setstacksize(&attr, stack_size);
844 } else {
845 // let pthread_create() pick the default value.
846 }
847
848 // glibc guard page
849 pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
850
851 ThreadState state;
852
853 {
854 // Serialize thread creation if we are running with fixed stack LinuxThreads
855 bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
856 if (lock) {
857 os::Linux::createThread_lock()->lock_without_safepoint_check();
858 }
859
860 pthread_t tid;
861 int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
862
863 pthread_attr_destroy(&attr);
864
865 if (ret != 0) {
866 if (PrintMiscellaneous && (Verbose || WizardMode)) {
867 perror("pthread_create()");
868 }
869 // Need to clean up stuff we've allocated so far
870 thread->set_osthread(NULL);
871 delete osthread;
872 if (lock) os::Linux::createThread_lock()->unlock();
873 return false;
874 }
875
876 // Store pthread info into the OSThread
877 osthread->set_pthread_id(tid);
878
879 // Wait until child thread is either initialized or aborted
880 {
881 Monitor* sync_with_child = osthread->startThread_lock();
882 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
883 while ((state = osthread->get_state()) == ALLOCATED) {
884 sync_with_child->wait(Mutex::_no_safepoint_check_flag);
885 }
886 }
887
888 if (lock) {
889 os::Linux::createThread_lock()->unlock();
890 }
891 }
892
893 // Aborted due to thread limit being reached
894 if (state == ZOMBIE) {
895 thread->set_osthread(NULL);
896 delete osthread;
897 return false;
898 }
899
900 // The thread is returned suspended (in state INITIALIZED),
901 // and is started higher up in the call chain
902 assert(state == INITIALIZED, "race condition");
903 return true;
904 }
905
906 /////////////////////////////////////////////////////////////////////////////
907 // attach existing thread
908
909 // bootstrap the main thread
910 bool os::create_main_thread(JavaThread* thread) {
911 assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
912 return create_attached_thread(thread);
913 }
914
915 bool os::create_attached_thread(JavaThread* thread) {
916 #ifdef ASSERT
917 thread->verify_not_published();
918 #endif
919
920 // Allocate the OSThread object
921 OSThread* osthread = new OSThread(NULL, NULL);
922
923 if (osthread == NULL) {
924 return false;
925 }
926
927 // Store pthread info into the OSThread
928 osthread->set_thread_id(os::Linux::gettid());
929 osthread->set_pthread_id(::pthread_self());
930
931 // initialize floating point control register
932 os::Linux::init_thread_fpu_state();
933
934 // Initial thread state is RUNNABLE
935 osthread->set_state(RUNNABLE);
936
937 thread->set_osthread(osthread);
938
939 if (UseNUMA) {
940 int lgrp_id = os::numa_get_group_id();
941 if (lgrp_id != -1) {
942 thread->set_lgrp_id(lgrp_id);
943 }
944 }
945
946 if (os::Linux::is_initial_thread()) {
947 // If current thread is initial thread, its stack is mapped on demand,
948 // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
949 // the entire stack region to avoid SEGV in stack banging.
950 // It is also useful to get around the heap-stack-gap problem on SuSE
951 // kernel (see 4821821 for details). We first expand stack to the top
952 // of yellow zone, then enable stack yellow zone (order is significant,
953 // enabling yellow zone first will crash JVM on SuSE Linux), so there
954 // is no gap between the last two virtual memory regions.
955
956 JavaThread *jt = (JavaThread *)thread;
957 address addr = jt->stack_yellow_zone_base();
958 assert(addr != NULL, "initialization problem?");
959 assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
960
961 osthread->set_expanding_stack();
962 os::Linux::manually_expand_stack(jt, addr);
963 osthread->clear_expanding_stack();
964 }
965
966 // initialize signal mask for this thread
967 // and save the caller's signal mask
968 os::Linux::hotspot_sigmask(thread);
969
970 return true;
971 }
972
973 void os::pd_start_thread(Thread* thread) {
974 OSThread * osthread = thread->osthread();
975 assert(osthread->get_state() != INITIALIZED, "just checking");
976 Monitor* sync_with_child = osthread->startThread_lock();
977 MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
978 sync_with_child->notify();
979 }
980
981 // Free Linux resources related to the OSThread
982 void os::free_thread(OSThread* osthread) {
983 assert(osthread != NULL, "osthread not set");
984
985 if (Thread::current()->osthread() == osthread) {
986 // Restore caller's signal mask
987 sigset_t sigmask = osthread->caller_sigmask();
988 pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
989 }
990
991 delete osthread;
992 }
993
994 //////////////////////////////////////////////////////////////////////////////
995 // thread local storage
996
997 int os::allocate_thread_local_storage() {
998 pthread_key_t key;
999 int rslt = pthread_key_create(&key, NULL);
1000 assert(rslt == 0, "cannot allocate thread local storage");
1001 return (int)key;
1002 }
1003
1004 // Note: This is currently not used by VM, as we don't destroy TLS key
1005 // on VM exit.
1006 void os::free_thread_local_storage(int index) {
1007 int rslt = pthread_key_delete((pthread_key_t)index);
1008 assert(rslt == 0, "invalid index");
1009 }
1010
1011 void os::thread_local_storage_at_put(int index, void* value) {
1012 int rslt = pthread_setspecific((pthread_key_t)index, value);
1013 assert(rslt == 0, "pthread_setspecific failed");
1014 }
1015
1016 extern "C" Thread* get_thread() {
1017 return ThreadLocalStorage::thread();
1018 }
1019
1020 //////////////////////////////////////////////////////////////////////////////
1021 // initial thread
1022
1023 // Check if current thread is the initial thread, similar to Solaris thr_main.
1024 bool os::Linux::is_initial_thread(void) {
1025 char dummy;
1026 // If called before init complete, thread stack bottom will be null.
1027 // Can be called if fatal error occurs before initialization.
1028 if (initial_thread_stack_bottom() == NULL) return false;
1029 assert(initial_thread_stack_bottom() != NULL &&
1030 initial_thread_stack_size() != 0,
1031 "os::init did not locate initial thread's stack region");
1032 if ((address)&dummy >= initial_thread_stack_bottom() &&
1033 (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
1034 return true;
1035 else return false;
1036 }
1037
1038 // Find the virtual memory area that contains addr
1039 static bool find_vma(address addr, address* vma_low, address* vma_high) {
1040 FILE *fp = fopen("/proc/self/maps", "r");
1041 if (fp) {
1042 address low, high;
1043 while (!feof(fp)) {
1044 if (fscanf(fp, "%p-%p", &low, &high) == 2) {
1045 if (low <= addr && addr < high) {
1046 if (vma_low) *vma_low = low;
1047 if (vma_high) *vma_high = high;
1048 fclose (fp);
1049 return true;
1050 }
1051 }
1052 for (;;) {
1053 int ch = fgetc(fp);
1054 if (ch == EOF || ch == (int)'\n') break;
1055 }
1056 }
1057 fclose(fp);
1058 }
1059 return false;
1060 }
1061
1062 // Locate initial thread stack. This special handling of initial thread stack
1063 // is needed because pthread_getattr_np() on most (all?) Linux distros returns
1064 // bogus value for initial thread.
1065 void os::Linux::capture_initial_stack(size_t max_size) {
1066 // stack size is the easy part, get it from RLIMIT_STACK
1067 size_t stack_size;
1068 struct rlimit rlim;
1069 getrlimit(RLIMIT_STACK, &rlim);
1070 stack_size = rlim.rlim_cur;
1071
1072 // 6308388: a bug in ld.so will relocate its own .data section to the
1073 // lower end of primordial stack; reduce ulimit -s value a little bit
1074 // so we won't install guard page on ld.so's data section.
1075 stack_size -= 2 * page_size();
1076
1077 // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
1078 // 7.1, in both cases we will get 2G in return value.
1079 // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
1080 // SuSE 7.2, Debian) can not handle alternate signal stack correctly
1081 // for initial thread if its stack size exceeds 6M. Cap it at 2M,
1082 // in case other parts in glibc still assumes 2M max stack size.
1083 // FIXME: alt signal stack is gone, maybe we can relax this constraint?
1084 #ifndef IA64
1085 if (stack_size > 2 * K * K) stack_size = 2 * K * K;
1086 #else
1087 // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
1088 if (stack_size > 4 * K * K) stack_size = 4 * K * K;
1089 #endif
1090
1091 // Try to figure out where the stack base (top) is. This is harder.
1092 //
1093 // When an application is started, glibc saves the initial stack pointer in
1094 // a global variable "__libc_stack_end", which is then used by system
1095 // libraries. __libc_stack_end should be pretty close to stack top. The
1096 // variable is available since the very early days. However, because it is
1097 // a private interface, it could disappear in the future.
1098 //
1099 // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
1100 // to __libc_stack_end, it is very close to stack top, but isn't the real
1101 // stack top. Note that /proc may not exist if VM is running as a chroot
1102 // program, so reading /proc/<pid>/stat could fail. Also the contents of
1103 // /proc/<pid>/stat could change in the future (though unlikely).
1104 //
1105 // We try __libc_stack_end first. If that doesn't work, look for
1106 // /proc/<pid>/stat. If neither of them works, we use current stack pointer
1107 // as a hint, which should work well in most cases.
1108
1109 uintptr_t stack_start;
1110
1111 // try __libc_stack_end first
1112 uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
1113 if (p && *p) {
1114 stack_start = *p;
1115 } else {
1116 // see if we can get the start_stack field from /proc/self/stat
1117 FILE *fp;
1118 int pid;
1119 char state;
1120 int ppid;
1121 int pgrp;
1122 int session;
1123 int nr;
1124 int tpgrp;
1125 unsigned long flags;
1126 unsigned long minflt;
1127 unsigned long cminflt;
1128 unsigned long majflt;
1129 unsigned long cmajflt;
1130 unsigned long utime;
1131 unsigned long stime;
1132 long cutime;
1133 long cstime;
1134 long prio;
1135 long nice;
1136 long junk;
1137 long it_real;
1138 uintptr_t start;
1139 uintptr_t vsize;
1140 uintptr_t rss;
1141 unsigned long rsslim;
1142 uintptr_t scodes;
1143 uintptr_t ecode;
1144 int i;
1145
1146 // Figure what the primordial thread stack base is. Code is inspired
1147 // by email from Hans Boehm. /proc/self/stat begins with current pid,
1148 // followed by command name surrounded by parentheses, state, etc.
1149 char stat[2048];
1150 int statlen;
1151
1152 fp = fopen("/proc/self/stat", "r");
1153 if (fp) {
1154 statlen = fread(stat, 1, 2047, fp);
1155 stat[statlen] = '\0';
1156 fclose(fp);
1157
1158 // Skip pid and the command string. Note that we could be dealing with
1159 // weird command names, e.g. user could decide to rename java launcher
1160 // to "java 1.4.2 :)", then the stat file would look like
1161 // 1234 (java 1.4.2 :)) R ... ...
1162 // We don't really need to know the command string, just find the last
1163 // occurrence of ")" and then start parsing from there. See bug 4726580.
1164 char * s = strrchr(stat, ')');
1165
1166 i = 0;
1167 if (s) {
1168 // Skip blank chars
1169 do s++; while (isspace(*s));
1170
1171 /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
1172 /* 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 */
1173 i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld "
1174 UINTX_FORMAT UINTX_FORMAT UINTX_FORMAT
1175 " %lu "
1176 UINTX_FORMAT UINTX_FORMAT UINTX_FORMAT,
1177 &state, /* 3 %c */
1178 &ppid, /* 4 %d */
1179 &pgrp, /* 5 %d */
1180 &session, /* 6 %d */
1181 &nr, /* 7 %d */
1182 &tpgrp, /* 8 %d */
1183 &flags, /* 9 %lu */
1184 &minflt, /* 10 %lu */
1185 &cminflt, /* 11 %lu */
1186 &majflt, /* 12 %lu */
1187 &cmajflt, /* 13 %lu */
1188 &utime, /* 14 %lu */
1189 &stime, /* 15 %lu */
1190 &cutime, /* 16 %ld */
1191 &cstime, /* 17 %ld */
1192 &prio, /* 18 %ld */
1193 &nice, /* 19 %ld */
1194 &junk, /* 20 %ld */
1195 &it_real, /* 21 %ld */
1196 &start, /* 22 UINTX_FORMAT */
1197 &vsize, /* 23 UINTX_FORMAT */
1198 &rss, /* 24 UINTX_FORMAT */
1199 &rsslim, /* 25 %lu */
1200 &scodes, /* 26 UINTX_FORMAT */
1201 &ecode, /* 27 UINTX_FORMAT */
1202 &stack_start); /* 28 UINTX_FORMAT */
1203 }
1204
1205 if (i != 28 - 2) {
1206 assert(false, "Bad conversion from /proc/self/stat");
1207 // product mode - assume we are the initial thread, good luck in the
1208 // embedded case.
1209 warning("Can't detect initial thread stack location - bad conversion");
1210 stack_start = (uintptr_t) &rlim;
1211 }
1212 } else {
1213 // For some reason we can't open /proc/self/stat (for example, running on
1214 // FreeBSD with a Linux emulator, or inside chroot), this should work for
1215 // most cases, so don't abort:
1216 warning("Can't detect initial thread stack location - no /proc/self/stat");
1217 stack_start = (uintptr_t) &rlim;
1218 }
1219 }
1220
1221 // Now we have a pointer (stack_start) very close to the stack top, the
1222 // next thing to do is to figure out the exact location of stack top. We
1223 // can find out the virtual memory area that contains stack_start by
1224 // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
1225 // and its upper limit is the real stack top. (again, this would fail if
1226 // running inside chroot, because /proc may not exist.)
1227
1228 uintptr_t stack_top;
1229 address low, high;
1230 if (find_vma((address)stack_start, &low, &high)) {
1231 // success, "high" is the true stack top. (ignore "low", because initial
1232 // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
1233 stack_top = (uintptr_t)high;
1234 } else {
1235 // failed, likely because /proc/self/maps does not exist
1236 warning("Can't detect initial thread stack location - find_vma failed");
1237 // best effort: stack_start is normally within a few pages below the real
1238 // stack top, use it as stack top, and reduce stack size so we won't put
1239 // guard page outside stack.
1240 stack_top = stack_start;
1241 stack_size -= 16 * page_size();
1242 }
1243
1244 // stack_top could be partially down the page so align it
1245 stack_top = align_size_up(stack_top, page_size());
1246
1247 if (max_size && stack_size > max_size) {
1248 _initial_thread_stack_size = max_size;
1249 } else {
1250 _initial_thread_stack_size = stack_size;
1251 }
1252
1253 _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
1254 _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
1255 }
1256
1257 ////////////////////////////////////////////////////////////////////////////////
1258 // time support
1259
1260 // Time since start-up in seconds to a fine granularity.
1261 // Used by VMSelfDestructTimer and the MemProfiler.
1262 double os::elapsedTime() {
1263
1264 return (double)(os::elapsed_counter()) * 0.000001;
1265 }
1266
1267 jlong os::elapsed_counter() {
1268 timeval time;
1269 int status = gettimeofday(&time, NULL);
1270 return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
1271 }
1272
1273 jlong os::elapsed_frequency() {
1274 return (1000 * 1000);
1275 }
1276
1277 // For now, we say that linux does not support vtime. I have no idea
1278 // whether it can actually be made to (DLD, 9/13/05).
1279
1280 bool os::supports_vtime() { return false; }
1281 bool os::enable_vtime() { return false; }
1282 bool os::vtime_enabled() { return false; }
1283 double os::elapsedVTime() {
1284 // better than nothing, but not much
1285 return elapsedTime();
1286 }
1287
1288 jlong os::javaTimeMillis() {
1289 timeval time;
1290 int status = gettimeofday(&time, NULL);
1291 assert(status != -1, "linux error");
1292 return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
1293 }
1294
1295 #ifndef CLOCK_MONOTONIC
1296 #define CLOCK_MONOTONIC (1)
1297 #endif
1298
1299 void os::Linux::clock_init() {
1300 // we do dlopen's in this particular order due to bug in linux
1301 // dynamical loader (see 6348968) leading to crash on exit
1302 void* handle = dlopen("librt.so.1", RTLD_LAZY);
1303 if (handle == NULL) {
1304 handle = dlopen("librt.so", RTLD_LAZY);
1305 }
1306
1307 if (handle) {
1308 int (*clock_getres_func)(clockid_t, struct timespec*) =
1309 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
1310 int (*clock_gettime_func)(clockid_t, struct timespec*) =
1311 (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
1312 if (clock_getres_func && clock_gettime_func) {
1313 // See if monotonic clock is supported by the kernel. Note that some
1314 // early implementations simply return kernel jiffies (updated every
1315 // 1/100 or 1/1000 second). It would be bad to use such a low res clock
1316 // for nano time (though the monotonic property is still nice to have).
1317 // It's fixed in newer kernels, however clock_getres() still returns
1318 // 1/HZ. We check if clock_getres() works, but will ignore its reported
1319 // resolution for now. Hopefully as people move to new kernels, this
1320 // won't be a problem.
1321 struct timespec res;
1322 struct timespec tp;
1323 if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
1324 clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
1325 // yes, monotonic clock is supported
1326 _clock_gettime = clock_gettime_func;
1327 } else {
1328 // close librt if there is no monotonic clock
1329 dlclose(handle);
1330 }
1331 }
1332 }
1333 }
1334
1335 #ifndef SYS_clock_getres
1336
1337 #if defined(IA32) || defined(AMD64)
1338 #define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
1339 #else
1340 #error Value of SYS_clock_getres not known on this platform
1341 #endif
1342
1343 #endif
1344
1345 #define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
1346
1347 void os::Linux::fast_thread_clock_init() {
1348 if (!UseLinuxPosixThreadCPUClocks) {
1349 return;
1350 }
1351 clockid_t clockid;
1352 struct timespec tp;
1353 int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
1354 (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
1355
1356 // Switch to using fast clocks for thread cpu time if
1357 // the sys_clock_getres() returns 0 error code.
1358 // Note, that some kernels may support the current thread
1359 // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
1360 // returned by the pthread_getcpuclockid().
1361 // If the fast Posix clocks are supported then the sys_clock_getres()
1362 // must return at least tp.tv_sec == 0 which means a resolution
1363 // better than 1 sec. This is extra check for reliability.
1364
1365 if(pthread_getcpuclockid_func &&
1366 pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
1367 sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
1368
1369 _supports_fast_thread_cpu_time = true;
1370 _pthread_getcpuclockid = pthread_getcpuclockid_func;
1371 }
1372 }
1373
1374 jlong os::javaTimeNanos() {
1375 if (Linux::supports_monotonic_clock()) {
1376 struct timespec tp;
1377 int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
1378 assert(status == 0, "gettime error");
1379 jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
1380 return result;
1381 } else {
1382 timeval time;
1383 int status = gettimeofday(&time, NULL);
1384 assert(status != -1, "linux error");
1385 jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
1386 return 1000 * usecs;
1387 }
1388 }
1389
1390 void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
1391 if (Linux::supports_monotonic_clock()) {
1392 info_ptr->max_value = ALL_64_BITS;
1393
1394 // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
1395 info_ptr->may_skip_backward = false; // not subject to resetting or drifting
1396 info_ptr->may_skip_forward = false; // not subject to resetting or drifting
1397 } else {
1398 // gettimeofday - based on time in seconds since the Epoch thus does not wrap
1399 info_ptr->max_value = ALL_64_BITS;
1400
1401 // gettimeofday is a real time clock so it skips
1402 info_ptr->may_skip_backward = true;
1403 info_ptr->may_skip_forward = true;
1404 }
1405
1406 info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
1407 }
1408
1409 // Return the real, user, and system times in seconds from an
1410 // arbitrary fixed point in the past.
1411 bool os::getTimesSecs(double* process_real_time,
1412 double* process_user_time,
1413 double* process_system_time) {
1414 struct tms ticks;
1415 clock_t real_ticks = times(&ticks);
1416
1417 if (real_ticks == (clock_t) (-1)) {
1418 return false;
1419 } else {
1420 double ticks_per_second = (double) clock_tics_per_sec;
1421 *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
1422 *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
1423 *process_real_time = ((double) real_ticks) / ticks_per_second;
1424
1425 return true;
1426 }
1427 }
1428
1429
1430 char * os::local_time_string(char *buf, size_t buflen) {
1431 struct tm t;
1432 time_t long_time;
1433 time(&long_time);
1434 localtime_r(&long_time, &t);
1435 jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
1436 t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
1437 t.tm_hour, t.tm_min, t.tm_sec);
1438 return buf;
1439 }
1440
1441 struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
1442 return localtime_r(clock, res);
1443 }
1444
1445 ////////////////////////////////////////////////////////////////////////////////
1446 // runtime exit support
1447
1448 // Note: os::shutdown() might be called very early during initialization, or
1449 // called from signal handler. Before adding something to os::shutdown(), make
1450 // sure it is async-safe and can handle partially initialized VM.
1451 void os::shutdown() {
1452
1453 // allow PerfMemory to attempt cleanup of any persistent resources
1454 perfMemory_exit();
1455
1456 // needs to remove object in file system
1457 AttachListener::abort();
1458
1459 // flush buffered output, finish log files
1460 ostream_abort();
1461
1462 // Check for abort hook
1463 abort_hook_t abort_hook = Arguments::abort_hook();
1464 if (abort_hook != NULL) {
1465 abort_hook();
1466 }
1467
1468 }
1469
1470 // Note: os::abort() might be called very early during initialization, or
1471 // called from signal handler. Before adding something to os::abort(), make
1472 // sure it is async-safe and can handle partially initialized VM.
1473 void os::abort(bool dump_core) {
1474 os::shutdown();
1475 if (dump_core) {
1476 #ifndef PRODUCT
1477 fdStream out(defaultStream::output_fd());
1478 out.print_raw("Current thread is ");
1479 char buf[16];
1480 jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
1481 out.print_raw_cr(buf);
1482 out.print_raw_cr("Dumping core ...");
1483 #endif
1484 ::abort(); // dump core
1485 }
1486
1487 ::exit(1);
1488 }
1489
1490 // Die immediately, no exit hook, no abort hook, no cleanup.
1491 void os::die() {
1492 // _exit() on LinuxThreads only kills current thread
1493 ::abort();
1494 }
1495
1496 // unused on linux for now.
1497 void os::set_error_file(const char *logfile) {}
1498
1499 intx os::current_thread_id() { return (intx)pthread_self(); }
1500 int os::current_process_id() {
1501
1502 // Under the old linux thread library, linux gives each thread
1503 // its own process id. Because of this each thread will return
1504 // a different pid if this method were to return the result
1505 // of getpid(2). Linux provides no api that returns the pid
1506 // of the launcher thread for the vm. This implementation
1507 // returns a unique pid, the pid of the launcher thread
1508 // that starts the vm 'process'.
1509
1510 // Under the NPTL, getpid() returns the same pid as the
1511 // launcher thread rather than a unique pid per thread.
1512 // Use gettid() if you want the old pre NPTL behaviour.
1513
1514 // if you are looking for the result of a call to getpid() that
1515 // returns a unique pid for the calling thread, then look at the
1516 // OSThread::thread_id() method in osThread_linux.hpp file
1517
1518 return (int)(_initial_pid ? _initial_pid : getpid());
1519 }
1520
1521 // DLL functions
1522
1523 const char* os::dll_file_extension() { return ".so"; }
1524
1525 const char* os::get_temp_directory() { return "/tmp/"; }
1526
1527 static bool file_exists(const char* filename) {
1528 struct stat statbuf;
1529 if (filename == NULL || strlen(filename) == 0) {
1530 return false;
1531 }
1532 return os::stat(filename, &statbuf) == 0;
1533 }
1534
1535 void os::dll_build_name(char* buffer, size_t buflen,
1536 const char* pname, const char* fname) {
1537 // Copied from libhpi
1538 const size_t pnamelen = pname ? strlen(pname) : 0;
1539
1540 // Quietly truncate on buffer overflow. Should be an error.
1541 if (pnamelen + strlen(fname) + 10 > (size_t) buflen) {
1542 *buffer = '\0';
1543 return;
1544 }
1545
1546 if (pnamelen == 0) {
1547 snprintf(buffer, buflen, "lib%s.so", fname);
1548 } else if (strchr(pname, *os::path_separator()) != NULL) {
1549 int n;
1550 char** pelements = split_path(pname, &n);
1551 for (int i = 0 ; i < n ; i++) {
1552 // Really shouldn't be NULL, but check can't hurt
1553 if (pelements[i] == NULL || strlen(pelements[i]) == 0) {
1554 continue; // skip the empty path values
1555 }
1556 snprintf(buffer, buflen, "%s/lib%s.so", pelements[i], fname);
1557 if (file_exists(buffer)) {
1558 break;
1559 }
1560 }
1561 // release the storage
1562 for (int i = 0 ; i < n ; i++) {
1563 if (pelements[i] != NULL) {
1564 FREE_C_HEAP_ARRAY(char, pelements[i]);
1565 }
1566 }
1567 if (pelements != NULL) {
1568 FREE_C_HEAP_ARRAY(char*, pelements);
1569 }
1570 } else {
1571 snprintf(buffer, buflen, "%s/lib%s.so", pname, fname);
1572 }
1573 }
1574
1575 const char* os::get_current_directory(char *buf, int buflen) {
1576 return getcwd(buf, buflen);
1577 }
1578
1579 // check if addr is inside libjvm[_g].so
1580 bool os::address_is_in_vm(address addr) {
1581 static address libjvm_base_addr;
1582 Dl_info dlinfo;
1583
1584 if (libjvm_base_addr == NULL) {
1585 dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo);
1586 libjvm_base_addr = (address)dlinfo.dli_fbase;
1587 assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
1588 }
1589
1590 if (dladdr((void *)addr, &dlinfo)) {
1591 if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
1592 }
1593
1594 return false;
1595 }
1596
1597 bool os::dll_address_to_function_name(address addr, char *buf,
1598 int buflen, int *offset) {
1599 Dl_info dlinfo;
1600
1601 if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) {
1602 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
1603 if (offset) *offset = addr - (address)dlinfo.dli_saddr;
1604 return true;
1605 } else {
1606 if (buf) buf[0] = '\0';
1607 if (offset) *offset = -1;
1608 return false;
1609 }
1610 }
1611
1612 struct _address_to_library_name {
1613 address addr; // input : memory address
1614 size_t buflen; // size of fname
1615 char* fname; // output: library name
1616 address base; // library base addr
1617 };
1618
1619 static int address_to_library_name_callback(struct dl_phdr_info *info,
1620 size_t size, void *data) {
1621 int i;
1622 bool found = false;
1623 address libbase = NULL;
1624 struct _address_to_library_name * d = (struct _address_to_library_name *)data;
1625
1626 // iterate through all loadable segments
1627 for (i = 0; i < info->dlpi_phnum; i++) {
1628 address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
1629 if (info->dlpi_phdr[i].p_type == PT_LOAD) {
1630 // base address of a library is the lowest address of its loaded
1631 // segments.
1632 if (libbase == NULL || libbase > segbase) {
1633 libbase = segbase;
1634 }
1635 // see if 'addr' is within current segment
1636 if (segbase <= d->addr &&
1637 d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
1638 found = true;
1639 }
1640 }
1641 }
1642
1643 // dlpi_name is NULL or empty if the ELF file is executable, return 0
1644 // so dll_address_to_library_name() can fall through to use dladdr() which
1645 // can figure out executable name from argv[0].
1646 if (found && info->dlpi_name && info->dlpi_name[0]) {
1647 d->base = libbase;
1648 if (d->fname) {
1649 jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
1650 }
1651 return 1;
1652 }
1653 return 0;
1654 }
1655
1656 bool os::dll_address_to_library_name(address addr, char* buf,
1657 int buflen, int* offset) {
1658 Dl_info dlinfo;
1659 struct _address_to_library_name data;
1660
1661 // There is a bug in old glibc dladdr() implementation that it could resolve
1662 // to wrong library name if the .so file has a base address != NULL. Here
1663 // we iterate through the program headers of all loaded libraries to find
1664 // out which library 'addr' really belongs to. This workaround can be
1665 // removed once the minimum requirement for glibc is moved to 2.3.x.
1666 data.addr = addr;
1667 data.fname = buf;
1668 data.buflen = buflen;
1669 data.base = NULL;
1670 int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
1671
1672 if (rslt) {
1673 // buf already contains library name
1674 if (offset) *offset = addr - data.base;
1675 return true;
1676 } else if (dladdr((void*)addr, &dlinfo)){
1677 if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
1678 if (offset) *offset = addr - (address)dlinfo.dli_fbase;
1679 return true;
1680 } else {
1681 if (buf) buf[0] = '\0';
1682 if (offset) *offset = -1;
1683 return false;
1684 }
1685 }
1686
1687 // Loads .dll/.so and
1688 // in case of error it checks if .dll/.so was built for the
1689 // same architecture as Hotspot is running on
1690
1691 void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
1692 {
1693 void * result= ::dlopen(filename, RTLD_LAZY);
1694 if (result != NULL) {
1695 // Successful loading
1696 return result;
1697 }
1698
1699 Elf32_Ehdr elf_head;
1700
1701 // Read system error message into ebuf
1702 // It may or may not be overwritten below
1703 ::strncpy(ebuf, ::dlerror(), ebuflen-1);
1704 ebuf[ebuflen-1]='\0';
1705 int diag_msg_max_length=ebuflen-strlen(ebuf);
1706 char* diag_msg_buf=ebuf+strlen(ebuf);
1707
1708 if (diag_msg_max_length==0) {
1709 // No more space in ebuf for additional diagnostics message
1710 return NULL;
1711 }
1712
1713
1714 int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
1715
1716 if (file_descriptor < 0) {
1717 // Can't open library, report dlerror() message
1718 return NULL;
1719 }
1720
1721 bool failed_to_read_elf_head=
1722 (sizeof(elf_head)!=
1723 (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
1724
1725 ::close(file_descriptor);
1726 if (failed_to_read_elf_head) {
1727 // file i/o error - report dlerror() msg
1728 return NULL;
1729 }
1730
1731 typedef struct {
1732 Elf32_Half code; // Actual value as defined in elf.h
1733 Elf32_Half compat_class; // Compatibility of archs at VM's sense
1734 char elf_class; // 32 or 64 bit
1735 char endianess; // MSB or LSB
1736 char* name; // String representation
1737 } arch_t;
1738
1739 #ifndef EM_486
1740 #define EM_486 6 /* Intel 80486 */
1741 #endif
1742
1743 static const arch_t arch_array[]={
1744 {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1745 {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
1746 {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
1747 {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
1748 {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1749 {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
1750 {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
1751 {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
1752 {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"},
1753 {EM_ARM, EM_ARM, ELFCLASS32, ELFDATA2LSB, (char*)"ARM"},
1754 {EM_S390, EM_S390, ELFCLASSNONE, ELFDATA2MSB, (char*)"IBM System/390"},
1755 {EM_ALPHA, EM_ALPHA, ELFCLASS64, ELFDATA2LSB, (char*)"Alpha"},
1756 {EM_MIPS_RS3_LE, EM_MIPS_RS3_LE, ELFCLASS32, ELFDATA2LSB, (char*)"MIPSel"},
1757 {EM_MIPS, EM_MIPS, ELFCLASS32, ELFDATA2MSB, (char*)"MIPS"},
1758 {EM_PARISC, EM_PARISC, ELFCLASS32, ELFDATA2MSB, (char*)"PARISC"},
1759 {EM_68K, EM_68K, ELFCLASS32, ELFDATA2MSB, (char*)"M68k"}
1760 };
1761
1762 #if (defined IA32)
1763 static Elf32_Half running_arch_code=EM_386;
1764 #elif (defined AMD64)
1765 static Elf32_Half running_arch_code=EM_X86_64;
1766 #elif (defined IA64)
1767 static Elf32_Half running_arch_code=EM_IA_64;
1768 #elif (defined __sparc) && (defined _LP64)
1769 static Elf32_Half running_arch_code=EM_SPARCV9;
1770 #elif (defined __sparc) && (!defined _LP64)
1771 static Elf32_Half running_arch_code=EM_SPARC;
1772 #elif (defined __powerpc64__)
1773 static Elf32_Half running_arch_code=EM_PPC64;
1774 #elif (defined __powerpc__)
1775 static Elf32_Half running_arch_code=EM_PPC;
1776 #elif (defined ARM)
1777 static Elf32_Half running_arch_code=EM_ARM;
1778 #elif (defined S390)
1779 static Elf32_Half running_arch_code=EM_S390;
1780 #elif (defined ALPHA)
1781 static Elf32_Half running_arch_code=EM_ALPHA;
1782 #elif (defined MIPSEL)
1783 static Elf32_Half running_arch_code=EM_MIPS_RS3_LE;
1784 #elif (defined PARISC)
1785 static Elf32_Half running_arch_code=EM_PARISC;
1786 #elif (defined MIPS)
1787 static Elf32_Half running_arch_code=EM_MIPS;
1788 #elif (defined M68K)
1789 static Elf32_Half running_arch_code=EM_68K;
1790 #else
1791 #error Method os::dll_load requires that one of following is defined:\
1792 IA32, AMD64, IA64, __sparc, __powerpc__, ARM, S390, ALPHA, MIPS, MIPSEL, PARISC, M68K
1793 #endif
1794
1795 // Identify compatability class for VM's architecture and library's architecture
1796 // Obtain string descriptions for architectures
1797
1798 arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
1799 int running_arch_index=-1;
1800
1801 for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
1802 if (running_arch_code == arch_array[i].code) {
1803 running_arch_index = i;
1804 }
1805 if (lib_arch.code == arch_array[i].code) {
1806 lib_arch.compat_class = arch_array[i].compat_class;
1807 lib_arch.name = arch_array[i].name;
1808 }
1809 }
1810
1811 assert(running_arch_index != -1,
1812 "Didn't find running architecture code (running_arch_code) in arch_array");
1813 if (running_arch_index == -1) {
1814 // Even though running architecture detection failed
1815 // we may still continue with reporting dlerror() message
1816 return NULL;
1817 }
1818
1819 if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
1820 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
1821 return NULL;
1822 }
1823
1824 #ifndef S390
1825 if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
1826 ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
1827 return NULL;
1828 }
1829 #endif // !S390
1830
1831 if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
1832 if ( lib_arch.name!=NULL ) {
1833 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1834 " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
1835 lib_arch.name, arch_array[running_arch_index].name);
1836 } else {
1837 ::snprintf(diag_msg_buf, diag_msg_max_length-1,
1838 " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
1839 lib_arch.code,
1840 arch_array[running_arch_index].name);
1841 }
1842 }
1843
1844 return NULL;
1845 }
1846
1847 /*
1848 * glibc-2.0 libdl is not MT safe. If you are building with any glibc,
1849 * chances are you might want to run the generated bits against glibc-2.0
1850 * libdl.so, so always use locking for any version of glibc.
1851 */
1852 void* os::dll_lookup(void* handle, const char* name) {
1853 pthread_mutex_lock(&dl_mutex);
1854 void* res = dlsym(handle, name);
1855 pthread_mutex_unlock(&dl_mutex);
1856 return res;
1857 }
1858
1859
1860 bool _print_ascii_file(const char* filename, outputStream* st) {
1861 int fd = open(filename, O_RDONLY);
1862 if (fd == -1) {
1863 return false;
1864 }
1865
1866 char buf[32];
1867 int bytes;
1868 while ((bytes = read(fd, buf, sizeof(buf))) > 0) {
1869 st->print_raw(buf, bytes);
1870 }
1871
1872 close(fd);
1873
1874 return true;
1875 }
1876
1877 void os::print_dll_info(outputStream *st) {
1878 st->print_cr("Dynamic libraries:");
1879
1880 char fname[32];
1881 pid_t pid = os::Linux::gettid();
1882
1883 jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
1884
1885 if (!_print_ascii_file(fname, st)) {
1886 st->print("Can not get library information for pid = %d\n", pid);
1887 }
1888 }
1889
1890
1891 void os::print_os_info(outputStream* st) {
1892 st->print("OS:");
1893
1894 // Try to identify popular distros.
1895 // Most Linux distributions have /etc/XXX-release file, which contains
1896 // the OS version string. Some have more than one /etc/XXX-release file
1897 // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.),
1898 // so the order is important.
1899 if (!_print_ascii_file("/etc/mandrake-release", st) &&
1900 !_print_ascii_file("/etc/sun-release", st) &&
1901 !_print_ascii_file("/etc/redhat-release", st) &&
1902 !_print_ascii_file("/etc/SuSE-release", st) &&
1903 !_print_ascii_file("/etc/turbolinux-release", st) &&
1904 !_print_ascii_file("/etc/gentoo-release", st) &&
1905 !_print_ascii_file("/etc/debian_version", st)) {
1906 st->print("Linux");
1907 }
1908 st->cr();
1909
1910 // kernel
1911 st->print("uname:");
1912 struct utsname name;
1913 uname(&name);
1914 st->print(name.sysname); st->print(" ");
1915 st->print(name.release); st->print(" ");
1916 st->print(name.version); st->print(" ");
1917 st->print(name.machine);
1918 st->cr();
1919
1920 // Print warning if unsafe chroot environment detected
1921 if (unsafe_chroot_detected) {
1922 st->print("WARNING!! ");
1923 st->print_cr(unstable_chroot_error);
1924 }
1925
1926 // libc, pthread
1927 st->print("libc:");
1928 st->print(os::Linux::glibc_version()); st->print(" ");
1929 st->print(os::Linux::libpthread_version()); st->print(" ");
1930 if (os::Linux::is_LinuxThreads()) {
1931 st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
1932 }
1933 st->cr();
1934
1935 // rlimit
1936 st->print("rlimit:");
1937 struct rlimit rlim;
1938
1939 st->print(" STACK ");
1940 getrlimit(RLIMIT_STACK, &rlim);
1941 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
1942 else st->print("%uk", rlim.rlim_cur >> 10);
1943
1944 st->print(", CORE ");
1945 getrlimit(RLIMIT_CORE, &rlim);
1946 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
1947 else st->print("%uk", rlim.rlim_cur >> 10);
1948
1949 st->print(", NPROC ");
1950 getrlimit(RLIMIT_NPROC, &rlim);
1951 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
1952 else st->print("%d", rlim.rlim_cur);
1953
1954 st->print(", NOFILE ");
1955 getrlimit(RLIMIT_NOFILE, &rlim);
1956 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
1957 else st->print("%d", rlim.rlim_cur);
1958
1959 st->print(", AS ");
1960 getrlimit(RLIMIT_AS, &rlim);
1961 if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
1962 else st->print("%uk", rlim.rlim_cur >> 10);
1963 st->cr();
1964
1965 // load average
1966 st->print("load average:");
1967 double loadavg[3];
1968 os::loadavg(loadavg, 3);
1969 st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
1970 st->cr();
1971 }
1972
1973 void os::print_memory_info(outputStream* st) {
1974
1975 st->print("Memory:");
1976 st->print(" %dk page", os::vm_page_size()>>10);
1977
1978 // values in struct sysinfo are "unsigned long"
1979 struct sysinfo si;
1980 sysinfo(&si);
1981
1982 st->print(", physical " UINT64_FORMAT "k",
1983 os::physical_memory() >> 10);
1984 st->print("(" UINT64_FORMAT "k free)",
1985 os::available_memory() >> 10);
1986 st->print(", swap " UINT64_FORMAT "k",
1987 ((jlong)si.totalswap * si.mem_unit) >> 10);
1988 st->print("(" UINT64_FORMAT "k free)",
1989 ((jlong)si.freeswap * si.mem_unit) >> 10);
1990 st->cr();
1991 }
1992
1993 // Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific
1994 // but they're the same for all the linux arch that we support
1995 // and they're the same for solaris but there's no common place to put this.
1996 const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR",
1997 "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG",
1998 "ILL_COPROC", "ILL_BADSTK" };
1999
2000 const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV",
2001 "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES",
2002 "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" };
2003
2004 const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" };
2005
2006 const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" };
2007
2008 void os::print_siginfo(outputStream* st, void* siginfo) {
2009 st->print("siginfo:");
2010
2011 const int buflen = 100;
2012 char buf[buflen];
2013 siginfo_t *si = (siginfo_t*)siginfo;
2014 st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen));
2015 if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) {
2016 st->print("si_errno=%s", buf);
2017 } else {
2018 st->print("si_errno=%d", si->si_errno);
2019 }
2020 const int c = si->si_code;
2021 assert(c > 0, "unexpected si_code");
2022 switch (si->si_signo) {
2023 case SIGILL:
2024 st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]);
2025 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2026 break;
2027 case SIGFPE:
2028 st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]);
2029 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2030 break;
2031 case SIGSEGV:
2032 st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]);
2033 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2034 break;
2035 case SIGBUS:
2036 st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]);
2037 st->print(", si_addr=" PTR_FORMAT, si->si_addr);
2038 break;
2039 default:
2040 st->print(", si_code=%d", si->si_code);
2041 // no si_addr
2042 }
2043
2044 if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
2045 UseSharedSpaces) {
2046 FileMapInfo* mapinfo = FileMapInfo::current_info();
2047 if (mapinfo->is_in_shared_space(si->si_addr)) {
2048 st->print("\n\nError accessing class data sharing archive." \
2049 " Mapped file inaccessible during execution, " \
2050 " possible disk/network problem.");
2051 }
2052 }
2053 st->cr();
2054 }
2055
2056
2057 static void print_signal_handler(outputStream* st, int sig,
2058 char* buf, size_t buflen);
2059
2060 void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
2061 st->print_cr("Signal Handlers:");
2062 print_signal_handler(st, SIGSEGV, buf, buflen);
2063 print_signal_handler(st, SIGBUS , buf, buflen);
2064 print_signal_handler(st, SIGFPE , buf, buflen);
2065 print_signal_handler(st, SIGPIPE, buf, buflen);
2066 print_signal_handler(st, SIGXFSZ, buf, buflen);
2067 print_signal_handler(st, SIGILL , buf, buflen);
2068 print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
2069 print_signal_handler(st, SR_signum, buf, buflen);
2070 print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
2071 print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
2072 print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
2073 print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
2074 }
2075
2076 static char saved_jvm_path[MAXPATHLEN] = {0};
2077
2078 // Find the full path to the current module, libjvm.so or libjvm_g.so
2079 void os::jvm_path(char *buf, jint len) {
2080 // Error checking.
2081 if (len < MAXPATHLEN) {
2082 assert(false, "must use a large-enough buffer");
2083 buf[0] = '\0';
2084 return;
2085 }
2086 // Lazy resolve the path to current module.
2087 if (saved_jvm_path[0] != 0) {
2088 strcpy(buf, saved_jvm_path);
2089 return;
2090 }
2091
2092 char dli_fname[MAXPATHLEN];
2093 bool ret = dll_address_to_library_name(
2094 CAST_FROM_FN_PTR(address, os::jvm_path),
2095 dli_fname, sizeof(dli_fname), NULL);
2096 assert(ret != 0, "cannot locate libjvm");
2097 if (realpath(dli_fname, buf) == NULL)
2098 return;
2099
2100 if (strcmp(Arguments::sun_java_launcher(), "gamma") == 0) {
2101 // Support for the gamma launcher. Typical value for buf is
2102 // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
2103 // the right place in the string, then assume we are installed in a JDK and
2104 // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
2105 // up the path so it looks like libjvm.so is installed there (append a
2106 // fake suffix hotspot/libjvm.so).
2107 const char *p = buf + strlen(buf) - 1;
2108 for (int count = 0; p > buf && count < 5; ++count) {
2109 for (--p; p > buf && *p != '/'; --p)
2110 /* empty */ ;
2111 }
2112
2113 if (strncmp(p, "/jre/lib/", 9) != 0) {
2114 // Look for JAVA_HOME in the environment.
2115 char* java_home_var = ::getenv("JAVA_HOME");
2116 if (java_home_var != NULL && java_home_var[0] != 0) {
2117 // Check the current module name "libjvm.so" or "libjvm_g.so".
2118 p = strrchr(buf, '/');
2119 assert(strstr(p, "/libjvm") == p, "invalid library name");
2120 p = strstr(p, "_g") ? "_g" : "";
2121
2122 if (realpath(java_home_var, buf) == NULL)
2123 return;
2124 sprintf(buf + strlen(buf), "/jre/lib/%s", cpu_arch);
2125 if (0 == access(buf, F_OK)) {
2126 // Use current module name "libjvm[_g].so" instead of
2127 // "libjvm"debug_only("_g")".so" since for fastdebug version
2128 // we should have "libjvm.so" but debug_only("_g") adds "_g"!
2129 // It is used when we are choosing the HPI library's name
2130 // "libhpi[_g].so" in hpi::initialize_get_interface().
2131 sprintf(buf + strlen(buf), "/hotspot/libjvm%s.so", p);
2132 } else {
2133 // Go back to path of .so
2134 if (realpath(dli_fname, buf) == NULL)
2135 return;
2136 }
2137 }
2138 }
2139 }
2140
2141 strcpy(saved_jvm_path, buf);
2142 }
2143
2144 void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
2145 // no prefix required, not even "_"
2146 }
2147
2148 void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
2149 // no suffix required
2150 }
2151
2152 ////////////////////////////////////////////////////////////////////////////////
2153 // sun.misc.Signal support
2154
2155 static volatile jint sigint_count = 0;
2156
2157 static void
2158 UserHandler(int sig, void *siginfo, void *context) {
2159 // 4511530 - sem_post is serialized and handled by the manager thread. When
2160 // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
2161 // don't want to flood the manager thread with sem_post requests.
2162 if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
2163 return;
2164
2165 // Ctrl-C is pressed during error reporting, likely because the error
2166 // handler fails to abort. Let VM die immediately.
2167 if (sig == SIGINT && is_error_reported()) {
2168 os::die();
2169 }
2170
2171 os::signal_notify(sig);
2172 }
2173
2174 void* os::user_handler() {
2175 return CAST_FROM_FN_PTR(void*, UserHandler);
2176 }
2177
2178 extern "C" {
2179 typedef void (*sa_handler_t)(int);
2180 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
2181 }
2182
2183 void* os::signal(int signal_number, void* handler) {
2184 struct sigaction sigAct, oldSigAct;
2185
2186 sigfillset(&(sigAct.sa_mask));
2187 sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
2188 sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
2189
2190 if (sigaction(signal_number, &sigAct, &oldSigAct)) {
2191 // -1 means registration failed
2192 return (void *)-1;
2193 }
2194
2195 return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
2196 }
2197
2198 void os::signal_raise(int signal_number) {
2199 ::raise(signal_number);
2200 }
2201
2202 /*
2203 * The following code is moved from os.cpp for making this
2204 * code platform specific, which it is by its very nature.
2205 */
2206
2207 // Will be modified when max signal is changed to be dynamic
2208 int os::sigexitnum_pd() {
2209 return NSIG;
2210 }
2211
2212 // a counter for each possible signal value
2213 static volatile jint pending_signals[NSIG+1] = { 0 };
2214
2215 // Linux(POSIX) specific hand shaking semaphore.
2216 static sem_t sig_sem;
2217
2218 void os::signal_init_pd() {
2219 // Initialize signal structures
2220 ::memset((void*)pending_signals, 0, sizeof(pending_signals));
2221
2222 // Initialize signal semaphore
2223 ::sem_init(&sig_sem, 0, 0);
2224 }
2225
2226 void os::signal_notify(int sig) {
2227 Atomic::inc(&pending_signals[sig]);
2228 ::sem_post(&sig_sem);
2229 }
2230
2231 static int check_pending_signals(bool wait) {
2232 Atomic::store(0, &sigint_count);
2233 for (;;) {
2234 for (int i = 0; i < NSIG + 1; i++) {
2235 jint n = pending_signals[i];
2236 if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
2237 return i;
2238 }
2239 }
2240 if (!wait) {
2241 return -1;
2242 }
2243 JavaThread *thread = JavaThread::current();
2244 ThreadBlockInVM tbivm(thread);
2245
2246 bool threadIsSuspended;
2247 do {
2248 thread->set_suspend_equivalent();
2249 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
2250 ::sem_wait(&sig_sem);
2251
2252 // were we externally suspended while we were waiting?
2253 threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
2254 if (threadIsSuspended) {
2255 //
2256 // The semaphore has been incremented, but while we were waiting
2257 // another thread suspended us. We don't want to continue running
2258 // while suspended because that would surprise the thread that
2259 // suspended us.
2260 //
2261 ::sem_post(&sig_sem);
2262
2263 thread->java_suspend_self();
2264 }
2265 } while (threadIsSuspended);
2266 }
2267 }
2268
2269 int os::signal_lookup() {
2270 return check_pending_signals(false);
2271 }
2272
2273 int os::signal_wait() {
2274 return check_pending_signals(true);
2275 }
2276
2277 ////////////////////////////////////////////////////////////////////////////////
2278 // Virtual Memory
2279
2280 int os::vm_page_size() {
2281 // Seems redundant as all get out
2282 assert(os::Linux::page_size() != -1, "must call os::init");
2283 return os::Linux::page_size();
2284 }
2285
2286 // Solaris allocates memory by pages.
2287 int os::vm_allocation_granularity() {
2288 assert(os::Linux::page_size() != -1, "must call os::init");
2289 return os::Linux::page_size();
2290 }
2291
2292 // Rationale behind this function:
2293 // current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
2294 // mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
2295 // samples for JITted code. Here we create private executable mapping over the code cache
2296 // and then we can use standard (well, almost, as mapping can change) way to provide
2297 // info for the reporting script by storing timestamp and location of symbol
2298 void linux_wrap_code(char* base, size_t size) {
2299 static volatile jint cnt = 0;
2300
2301 if (!UseOprofile) {
2302 return;
2303 }
2304
2305 char buf[40];
2306 int num = Atomic::add(1, &cnt);
2307
2308 sprintf(buf, "/tmp/hs-vm-%d-%d", os::current_process_id(), num);
2309 unlink(buf);
2310
2311 int fd = open(buf, O_CREAT | O_RDWR, S_IRWXU);
2312
2313 if (fd != -1) {
2314 off_t rv = lseek(fd, size-2, SEEK_SET);
2315 if (rv != (off_t)-1) {
2316 if (write(fd, "", 1) == 1) {
2317 mmap(base, size,
2318 PROT_READ|PROT_WRITE|PROT_EXEC,
2319 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
2320 }
2321 }
2322 close(fd);
2323 unlink(buf);
2324 }
2325 }
2326
2327 // NOTE: Linux kernel does not really reserve the pages for us.
2328 // All it does is to check if there are enough free pages
2329 // left at the time of mmap(). This could be a potential
2330 // problem.
2331 bool os::commit_memory(char* addr, size_t size, bool exec) {
2332 int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
2333 uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
2334 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2335 return res != (uintptr_t) MAP_FAILED;
2336 }
2337
2338 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
2339 bool exec) {
2340 return commit_memory(addr, size, exec);
2341 }
2342
2343 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { }
2344
2345 void os::free_memory(char *addr, size_t bytes) {
2346 ::mmap(addr, bytes, PROT_READ | PROT_WRITE,
2347 MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
2348 }
2349
2350 void os::numa_make_global(char *addr, size_t bytes) {
2351 Linux::numa_interleave_memory(addr, bytes);
2352 }
2353
2354 void os::numa_make_local(char *addr, size_t bytes, int lgrp_hint) {
2355 Linux::numa_tonode_memory(addr, bytes, lgrp_hint);
2356 }
2357
2358 bool os::numa_topology_changed() { return false; }
2359
2360 size_t os::numa_get_groups_num() {
2361 int max_node = Linux::numa_max_node();
2362 return max_node > 0 ? max_node + 1 : 1;
2363 }
2364
2365 int os::numa_get_group_id() {
2366 int cpu_id = Linux::sched_getcpu();
2367 if (cpu_id != -1) {
2368 int lgrp_id = Linux::get_node_by_cpu(cpu_id);
2369 if (lgrp_id != -1) {
2370 return lgrp_id;
2371 }
2372 }
2373 return 0;
2374 }
2375
2376 size_t os::numa_get_leaf_groups(int *ids, size_t size) {
2377 for (size_t i = 0; i < size; i++) {
2378 ids[i] = i;
2379 }
2380 return size;
2381 }
2382
2383 bool os::get_page_info(char *start, page_info* info) {
2384 return false;
2385 }
2386
2387 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
2388 return end;
2389 }
2390
2391 extern "C" void numa_warn(int number, char *where, ...) { }
2392 extern "C" void numa_error(char *where) { }
2393
2394
2395 // If we are running with libnuma version > 2, then we should
2396 // be trying to use symbols with versions 1.1
2397 // If we are running with earlier version, which did not have symbol versions,
2398 // we should use the base version.
2399 void* os::Linux::libnuma_dlsym(void* handle, const char *name) {
2400 void *f = dlvsym(handle, name, "libnuma_1.1");
2401 if (f == NULL) {
2402 f = dlsym(handle, name);
2403 }
2404 return f;
2405 }
2406
2407 bool os::Linux::libnuma_init() {
2408 // sched_getcpu() should be in libc.
2409 set_sched_getcpu(CAST_TO_FN_PTR(sched_getcpu_func_t,
2410 dlsym(RTLD_DEFAULT, "sched_getcpu")));
2411
2412 if (sched_getcpu() != -1) { // Does it work?
2413 void *handle = dlopen("libnuma.so.1", RTLD_LAZY);
2414 if (handle != NULL) {
2415 set_numa_node_to_cpus(CAST_TO_FN_PTR(numa_node_to_cpus_func_t,
2416 libnuma_dlsym(handle, "numa_node_to_cpus")));
2417 set_numa_max_node(CAST_TO_FN_PTR(numa_max_node_func_t,
2418 libnuma_dlsym(handle, "numa_max_node")));
2419 set_numa_available(CAST_TO_FN_PTR(numa_available_func_t,
2420 libnuma_dlsym(handle, "numa_available")));
2421 set_numa_tonode_memory(CAST_TO_FN_PTR(numa_tonode_memory_func_t,
2422 libnuma_dlsym(handle, "numa_tonode_memory")));
2423 set_numa_interleave_memory(CAST_TO_FN_PTR(numa_interleave_memory_func_t,
2424 libnuma_dlsym(handle, "numa_interleave_memory")));
2425
2426
2427 if (numa_available() != -1) {
2428 set_numa_all_nodes((unsigned long*)libnuma_dlsym(handle, "numa_all_nodes"));
2429 // Create a cpu -> node mapping
2430 _cpu_to_node = new (ResourceObj::C_HEAP) GrowableArray<int>(0, true);
2431 rebuild_cpu_to_node_map();
2432 return true;
2433 }
2434 }
2435 }
2436 return false;
2437 }
2438
2439 // rebuild_cpu_to_node_map() constructs a table mapping cpud id to node id.
2440 // The table is later used in get_node_by_cpu().
2441 void os::Linux::rebuild_cpu_to_node_map() {
2442 const size_t NCPUS = 32768; // Since the buffer size computation is very obscure
2443 // in libnuma (possible values are starting from 16,
2444 // and continuing up with every other power of 2, but less
2445 // than the maximum number of CPUs supported by kernel), and
2446 // is a subject to change (in libnuma version 2 the requirements
2447 // are more reasonable) we'll just hardcode the number they use
2448 // in the library.
2449 const size_t BitsPerCLong = sizeof(long) * CHAR_BIT;
2450
2451 size_t cpu_num = os::active_processor_count();
2452 size_t cpu_map_size = NCPUS / BitsPerCLong;
2453 size_t cpu_map_valid_size =
2454 MIN2((cpu_num + BitsPerCLong - 1) / BitsPerCLong, cpu_map_size);
2455
2456 cpu_to_node()->clear();
2457 cpu_to_node()->at_grow(cpu_num - 1);
2458 size_t node_num = numa_get_groups_num();
2459
2460 unsigned long *cpu_map = NEW_C_HEAP_ARRAY(unsigned long, cpu_map_size);
2461 for (size_t i = 0; i < node_num; i++) {
2462 if (numa_node_to_cpus(i, cpu_map, cpu_map_size * sizeof(unsigned long)) != -1) {
2463 for (size_t j = 0; j < cpu_map_valid_size; j++) {
2464 if (cpu_map[j] != 0) {
2465 for (size_t k = 0; k < BitsPerCLong; k++) {
2466 if (cpu_map[j] & (1UL << k)) {
2467 cpu_to_node()->at_put(j * BitsPerCLong + k, i);
2468 }
2469 }
2470 }
2471 }
2472 }
2473 }
2474 FREE_C_HEAP_ARRAY(unsigned long, cpu_map);
2475 }
2476
2477 int os::Linux::get_node_by_cpu(int cpu_id) {
2478 if (cpu_to_node() != NULL && cpu_id >= 0 && cpu_id < cpu_to_node()->length()) {
2479 return cpu_to_node()->at(cpu_id);
2480 }
2481 return -1;
2482 }
2483
2484 GrowableArray<int>* os::Linux::_cpu_to_node;
2485 os::Linux::sched_getcpu_func_t os::Linux::_sched_getcpu;
2486 os::Linux::numa_node_to_cpus_func_t os::Linux::_numa_node_to_cpus;
2487 os::Linux::numa_max_node_func_t os::Linux::_numa_max_node;
2488 os::Linux::numa_available_func_t os::Linux::_numa_available;
2489 os::Linux::numa_tonode_memory_func_t os::Linux::_numa_tonode_memory;
2490 os::Linux::numa_interleave_memory_func_t os::Linux::_numa_interleave_memory;
2491 unsigned long* os::Linux::_numa_all_nodes;
2492
2493 bool os::uncommit_memory(char* addr, size_t size) {
2494 return ::mmap(addr, size, PROT_NONE,
2495 MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0)
2496 != MAP_FAILED;
2497 }
2498
2499 // Linux uses a growable mapping for the stack, and if the mapping for
2500 // the stack guard pages is not removed when we detach a thread the
2501 // stack cannot grow beyond the pages where the stack guard was
2502 // mapped. If at some point later in the process the stack expands to
2503 // that point, the Linux kernel cannot expand the stack any further
2504 // because the guard pages are in the way, and a segfault occurs.
2505 //
2506 // However, it's essential not to split the stack region by unmapping
2507 // a region (leaving a hole) that's already part of the stack mapping,
2508 // so if the stack mapping has already grown beyond the guard pages at
2509 // the time we create them, we have to truncate the stack mapping.
2510 // So, we need to know the extent of the stack mapping when
2511 // create_stack_guard_pages() is called.
2512
2513 // Find the bounds of the stack mapping. Return true for success.
2514 //
2515 // We only need this for stacks that are growable: at the time of
2516 // writing thread stacks don't use growable mappings (i.e. those
2517 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
2518 // only applies to the main thread.
2519 static bool
2520 get_stack_bounds(uintptr_t *bottom, uintptr_t *top)
2521 {
2522 FILE *f = fopen("/proc/self/maps", "r");
2523 if (f == NULL)
2524 return false;
2525
2526 while (!feof(f)) {
2527 size_t dummy;
2528 char *str = NULL;
2529 ssize_t len = getline(&str, &dummy, f);
2530 if (len == -1) {
2531 return false;
2532 }
2533
2534 if (len > 0 && str[len-1] == '\n') {
2535 str[len-1] = 0;
2536 len--;
2537 }
2538
2539 static const char *stack_str = "[stack]";
2540 if (len > (ssize_t)strlen(stack_str)
2541 && (strcmp(str + len - strlen(stack_str), stack_str)
2542 == 0)) {
2543 if (sscanf(str, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
2544 uintptr_t sp = (uintptr_t)__builtin_frame_address(0);
2545 if (sp >= *bottom && sp <= *top) {
2546 free(str);
2547 return true;
2548 }
2549 }
2550 }
2551
2552 free(str);
2553 }
2554
2555 return false;
2556 }
2557
2558 // If the (growable) stack mapping already extends beyond the point
2559 // where we're going to put our guard pages, truncate the mapping at
2560 // that point by munmap()ping it. This ensures that when we later
2561 // munmap() the guard pages we don't leave a hole in the stack
2562 // mapping.
2563 bool os::create_stack_guard_pages(char* addr, size_t size) {
2564 uintptr_t stack_extent, stack_base;
2565 if (get_stack_bounds(&stack_extent, &stack_base)) {
2566 if (stack_extent < (uintptr_t)addr)
2567 ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent);
2568 }
2569
2570 return os::commit_memory(addr, size);
2571 }
2572
2573 // If this is a growable mapping, remove the guard pages entirely by
2574 // munmap()ping them. If not, just call uncommit_memory().
2575 bool os::remove_stack_guard_pages(char* addr, size_t size) {
2576 uintptr_t stack_extent, stack_base;
2577 if (get_stack_bounds(&stack_extent, &stack_base)) {
2578 return ::munmap(addr, size) == 0;
2579 }
2580
2581 return os::uncommit_memory(addr, size);
2582 }
2583
2584 static address _highest_vm_reserved_address = NULL;
2585
2586 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
2587 // at 'requested_addr'. If there are existing memory mappings at the same
2588 // location, however, they will be overwritten. If 'fixed' is false,
2589 // 'requested_addr' is only treated as a hint, the return value may or
2590 // may not start from the requested address. Unlike Linux mmap(), this
2591 // function returns NULL to indicate failure.
2592 static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
2593 char * addr;
2594 int flags;
2595
2596 flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
2597 if (fixed) {
2598 assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
2599 flags |= MAP_FIXED;
2600 }
2601
2602 // Map uncommitted pages PROT_READ and PROT_WRITE, change access
2603 // to PROT_EXEC if executable when we commit the page.
2604 addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE,
2605 flags, -1, 0);
2606
2607 if (addr != MAP_FAILED) {
2608 // anon_mmap() should only get called during VM initialization,
2609 // don't need lock (actually we can skip locking even it can be called
2610 // from multiple threads, because _highest_vm_reserved_address is just a
2611 // hint about the upper limit of non-stack memory regions.)
2612 if ((address)addr + bytes > _highest_vm_reserved_address) {
2613 _highest_vm_reserved_address = (address)addr + bytes;
2614 }
2615 }
2616
2617 return addr == MAP_FAILED ? NULL : addr;
2618 }
2619
2620 // Don't update _highest_vm_reserved_address, because there might be memory
2621 // regions above addr + size. If so, releasing a memory region only creates
2622 // a hole in the address space, it doesn't help prevent heap-stack collision.
2623 //
2624 static int anon_munmap(char * addr, size_t size) {
2625 return ::munmap(addr, size) == 0;
2626 }
2627
2628 char* os::reserve_memory(size_t bytes, char* requested_addr,
2629 size_t alignment_hint) {
2630 return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
2631 }
2632
2633 bool os::release_memory(char* addr, size_t size) {
2634 return anon_munmap(addr, size);
2635 }
2636
2637 static address highest_vm_reserved_address() {
2638 return _highest_vm_reserved_address;
2639 }
2640
2641 static bool linux_mprotect(char* addr, size_t size, int prot) {
2642 // Linux wants the mprotect address argument to be page aligned.
2643 char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
2644
2645 // According to SUSv3, mprotect() should only be used with mappings
2646 // established by mmap(), and mmap() always maps whole pages. Unaligned
2647 // 'addr' likely indicates problem in the VM (e.g. trying to change
2648 // protection of malloc'ed or statically allocated memory). Check the
2649 // caller if you hit this assert.
2650 assert(addr == bottom, "sanity check");
2651
2652 size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
2653 return ::mprotect(bottom, size, prot) == 0;
2654 }
2655
2656 // Set protections specified
2657 bool os::protect_memory(char* addr, size_t bytes, ProtType prot,
2658 bool is_committed) {
2659 unsigned int p = 0;
2660 switch (prot) {
2661 case MEM_PROT_NONE: p = PROT_NONE; break;
2662 case MEM_PROT_READ: p = PROT_READ; break;
2663 case MEM_PROT_RW: p = PROT_READ|PROT_WRITE; break;
2664 case MEM_PROT_RWX: p = PROT_READ|PROT_WRITE|PROT_EXEC; break;
2665 default:
2666 ShouldNotReachHere();
2667 }
2668 // is_committed is unused.
2669 return linux_mprotect(addr, bytes, p);
2670 }
2671
2672 bool os::guard_memory(char* addr, size_t size) {
2673 return linux_mprotect(addr, size, PROT_NONE);
2674 }
2675
2676 bool os::unguard_memory(char* addr, size_t size) {
2677 return linux_mprotect(addr, size, PROT_READ|PROT_WRITE);
2678 }
2679
2680 // Large page support
2681
2682 static size_t _large_page_size = 0;
2683
2684 bool os::large_page_init() {
2685 if (!UseLargePages) return false;
2686
2687 if (LargePageSizeInBytes) {
2688 _large_page_size = LargePageSizeInBytes;
2689 } else {
2690 // large_page_size on Linux is used to round up heap size. x86 uses either
2691 // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
2692 // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
2693 // page as large as 256M.
2694 //
2695 // Here we try to figure out page size by parsing /proc/meminfo and looking
2696 // for a line with the following format:
2697 // Hugepagesize: 2048 kB
2698 //
2699 // If we can't determine the value (e.g. /proc is not mounted, or the text
2700 // format has been changed), we'll use the largest page size supported by
2701 // the processor.
2702
2703 #ifndef ZERO
2704 _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M);
2705 #endif // ZERO
2706
2707 FILE *fp = fopen("/proc/meminfo", "r");
2708 if (fp) {
2709 while (!feof(fp)) {
2710 int x = 0;
2711 char buf[16];
2712 if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
2713 if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
2714 _large_page_size = x * K;
2715 break;
2716 }
2717 } else {
2718 // skip to next line
2719 for (;;) {
2720 int ch = fgetc(fp);
2721 if (ch == EOF || ch == (int)'\n') break;
2722 }
2723 }
2724 }
2725 fclose(fp);
2726 }
2727 }
2728
2729 const size_t default_page_size = (size_t)Linux::page_size();
2730 if (_large_page_size > default_page_size) {
2731 _page_sizes[0] = _large_page_size;
2732 _page_sizes[1] = default_page_size;
2733 _page_sizes[2] = 0;
2734 }
2735
2736 // Large page support is available on 2.6 or newer kernel, some vendors
2737 // (e.g. Redhat) have backported it to their 2.4 based distributions.
2738 // We optimistically assume the support is available. If later it turns out
2739 // not true, VM will automatically switch to use regular page size.
2740 return true;
2741 }
2742
2743 #ifndef SHM_HUGETLB
2744 #define SHM_HUGETLB 04000
2745 #endif
2746
2747 char* os::reserve_memory_special(size_t bytes, char* req_addr, bool exec) {
2748 // "exec" is passed in but not used. Creating the shared image for
2749 // the code cache doesn't have an SHM_X executable permission to check.
2750 assert(UseLargePages, "only for large pages");
2751
2752 key_t key = IPC_PRIVATE;
2753 char *addr;
2754
2755 bool warn_on_failure = UseLargePages &&
2756 (!FLAG_IS_DEFAULT(UseLargePages) ||
2757 !FLAG_IS_DEFAULT(LargePageSizeInBytes)
2758 );
2759 char msg[128];
2760
2761 // Create a large shared memory region to attach to based on size.
2762 // Currently, size is the total size of the heap
2763 int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
2764 if (shmid == -1) {
2765 // Possible reasons for shmget failure:
2766 // 1. shmmax is too small for Java heap.
2767 // > check shmmax value: cat /proc/sys/kernel/shmmax
2768 // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
2769 // 2. not enough large page memory.
2770 // > check available large pages: cat /proc/meminfo
2771 // > increase amount of large pages:
2772 // echo new_value > /proc/sys/vm/nr_hugepages
2773 // Note 1: different Linux may use different name for this property,
2774 // e.g. on Redhat AS-3 it is "hugetlb_pool".
2775 // Note 2: it's possible there's enough physical memory available but
2776 // they are so fragmented after a long run that they can't
2777 // coalesce into large pages. Try to reserve large pages when
2778 // the system is still "fresh".
2779 if (warn_on_failure) {
2780 jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
2781 warning(msg);
2782 }
2783 return NULL;
2784 }
2785
2786 // attach to the region
2787 addr = (char*)shmat(shmid, NULL, 0);
2788 int err = errno;
2789
2790 // Remove shmid. If shmat() is successful, the actual shared memory segment
2791 // will be deleted when it's detached by shmdt() or when the process
2792 // terminates. If shmat() is not successful this will remove the shared
2793 // segment immediately.
2794 shmctl(shmid, IPC_RMID, NULL);
2795
2796 if ((intptr_t)addr == -1) {
2797 if (warn_on_failure) {
2798 jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
2799 warning(msg);
2800 }
2801 return NULL;
2802 }
2803
2804 return addr;
2805 }
2806
2807 bool os::release_memory_special(char* base, size_t bytes) {
2808 // detaching the SHM segment will also delete it, see reserve_memory_special()
2809 int rslt = shmdt(base);
2810 return rslt == 0;
2811 }
2812
2813 size_t os::large_page_size() {
2814 return _large_page_size;
2815 }
2816
2817 // Linux does not support anonymous mmap with large page memory. The only way
2818 // to reserve large page memory without file backing is through SysV shared
2819 // memory API. The entire memory region is committed and pinned upfront.
2820 // Hopefully this will change in the future...
2821 bool os::can_commit_large_page_memory() {
2822 return false;
2823 }
2824
2825 bool os::can_execute_large_page_memory() {
2826 return false;
2827 }
2828
2829 // Reserve memory at an arbitrary address, only if that area is
2830 // available (and not reserved for something else).
2831
2832 char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
2833 const int max_tries = 10;
2834 char* base[max_tries];
2835 size_t size[max_tries];
2836 const size_t gap = 0x000000;
2837
2838 // Assert only that the size is a multiple of the page size, since
2839 // that's all that mmap requires, and since that's all we really know
2840 // about at this low abstraction level. If we need higher alignment,
2841 // we can either pass an alignment to this method or verify alignment
2842 // in one of the methods further up the call chain. See bug 5044738.
2843 assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
2844
2845 // Repeatedly allocate blocks until the block is allocated at the
2846 // right spot. Give up after max_tries. Note that reserve_memory() will
2847 // automatically update _highest_vm_reserved_address if the call is
2848 // successful. The variable tracks the highest memory address every reserved
2849 // by JVM. It is used to detect heap-stack collision if running with
2850 // fixed-stack LinuxThreads. Because here we may attempt to reserve more
2851 // space than needed, it could confuse the collision detecting code. To
2852 // solve the problem, save current _highest_vm_reserved_address and
2853 // calculate the correct value before return.
2854 address old_highest = _highest_vm_reserved_address;
2855
2856 // Linux mmap allows caller to pass an address as hint; give it a try first,
2857 // if kernel honors the hint then we can return immediately.
2858 char * addr = anon_mmap(requested_addr, bytes, false);
2859 if (addr == requested_addr) {
2860 return requested_addr;
2861 }
2862
2863 if (addr != NULL) {
2864 // mmap() is successful but it fails to reserve at the requested address
2865 anon_munmap(addr, bytes);
2866 }
2867
2868 int i;
2869 for (i = 0; i < max_tries; ++i) {
2870 base[i] = reserve_memory(bytes);
2871
2872 if (base[i] != NULL) {
2873 // Is this the block we wanted?
2874 if (base[i] == requested_addr) {
2875 size[i] = bytes;
2876 break;
2877 }
2878
2879 // Does this overlap the block we wanted? Give back the overlapped
2880 // parts and try again.
2881
2882 size_t top_overlap = requested_addr + (bytes + gap) - base[i];
2883 if (top_overlap >= 0 && top_overlap < bytes) {
2884 unmap_memory(base[i], top_overlap);
2885 base[i] += top_overlap;
2886 size[i] = bytes - top_overlap;
2887 } else {
2888 size_t bottom_overlap = base[i] + bytes - requested_addr;
2889 if (bottom_overlap >= 0 && bottom_overlap < bytes) {
2890 unmap_memory(requested_addr, bottom_overlap);
2891 size[i] = bytes - bottom_overlap;
2892 } else {
2893 size[i] = bytes;
2894 }
2895 }
2896 }
2897 }
2898
2899 // Give back the unused reserved pieces.
2900
2901 for (int j = 0; j < i; ++j) {
2902 if (base[j] != NULL) {
2903 unmap_memory(base[j], size[j]);
2904 }
2905 }
2906
2907 if (i < max_tries) {
2908 _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
2909 return requested_addr;
2910 } else {
2911 _highest_vm_reserved_address = old_highest;
2912 return NULL;
2913 }
2914 }
2915
2916 size_t os::read(int fd, void *buf, unsigned int nBytes) {
2917 return ::read(fd, buf, nBytes);
2918 }
2919
2920 // TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
2921 // Solaris uses poll(), linux uses park().
2922 // Poll() is likely a better choice, assuming that Thread.interrupt()
2923 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
2924 // SIGSEGV, see 4355769.
2925
2926 const int NANOSECS_PER_MILLISECS = 1000000;
2927
2928 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
2929 assert(thread == Thread::current(), "thread consistency check");
2930
2931 ParkEvent * const slp = thread->_SleepEvent ;
2932 slp->reset() ;
2933 OrderAccess::fence() ;
2934
2935 if (interruptible) {
2936 jlong prevtime = javaTimeNanos();
2937
2938 for (;;) {
2939 if (os::is_interrupted(thread, true)) {
2940 return OS_INTRPT;
2941 }
2942
2943 jlong newtime = javaTimeNanos();
2944
2945 if (newtime - prevtime < 0) {
2946 // time moving backwards, should only happen if no monotonic clock
2947 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2948 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
2949 } else {
2950 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
2951 }
2952
2953 if(millis <= 0) {
2954 return OS_OK;
2955 }
2956
2957 prevtime = newtime;
2958
2959 {
2960 assert(thread->is_Java_thread(), "sanity check");
2961 JavaThread *jt = (JavaThread *) thread;
2962 ThreadBlockInVM tbivm(jt);
2963 OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
2964
2965 jt->set_suspend_equivalent();
2966 // cleared by handle_special_suspend_equivalent_condition() or
2967 // java_suspend_self() via check_and_wait_while_suspended()
2968
2969 slp->park(millis);
2970
2971 // were we externally suspended while we were waiting?
2972 jt->check_and_wait_while_suspended();
2973 }
2974 }
2975 } else {
2976 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
2977 jlong prevtime = javaTimeNanos();
2978
2979 for (;;) {
2980 // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
2981 // the 1st iteration ...
2982 jlong newtime = javaTimeNanos();
2983
2984 if (newtime - prevtime < 0) {
2985 // time moving backwards, should only happen if no monotonic clock
2986 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2987 assert(!Linux::supports_monotonic_clock(), "time moving backwards");
2988 } else {
2989 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
2990 }
2991
2992 if(millis <= 0) break ;
2993
2994 prevtime = newtime;
2995 slp->park(millis);
2996 }
2997 return OS_OK ;
2998 }
2999 }
3000
3001 int os::naked_sleep() {
3002 // %% make the sleep time an integer flag. for now use 1 millisec.
3003 return os::sleep(Thread::current(), 1, false);
3004 }
3005
3006 // Sleep forever; naked call to OS-specific sleep; use with CAUTION
3007 void os::infinite_sleep() {
3008 while (true) { // sleep forever ...
3009 ::sleep(100); // ... 100 seconds at a time
3010 }
3011 }
3012
3013 // Used to convert frequent JVM_Yield() to nops
3014 bool os::dont_yield() {
3015 return DontYieldALot;
3016 }
3017
3018 void os::yield() {
3019 sched_yield();
3020 }
3021
3022 os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
3023
3024 void os::yield_all(int attempts) {
3025 // Yields to all threads, including threads with lower priorities
3026 // Threads on Linux are all with same priority. The Solaris style
3027 // os::yield_all() with nanosleep(1ms) is not necessary.
3028 sched_yield();
3029 }
3030
3031 // Called from the tight loops to possibly influence time-sharing heuristics
3032 void os::loop_breaker(int attempts) {
3033 os::yield_all(attempts);
3034 }
3035
3036 ////////////////////////////////////////////////////////////////////////////////
3037 // thread priority support
3038
3039 // Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
3040 // only supports dynamic priority, static priority must be zero. For real-time
3041 // applications, Linux supports SCHED_RR which allows static priority (1-99).
3042 // However, for large multi-threaded applications, SCHED_RR is not only slower
3043 // than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
3044 // of 5 runs - Sep 2005).
3045 //
3046 // The following code actually changes the niceness of kernel-thread/LWP. It
3047 // has an assumption that setpriority() only modifies one kernel-thread/LWP,
3048 // not the entire user process, and user level threads are 1:1 mapped to kernel
3049 // threads. It has always been the case, but could change in the future. For
3050 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
3051 // It is only used when ThreadPriorityPolicy=1 and requires root privilege.
3052
3053 int os::java_to_os_priority[MaxPriority + 1] = {
3054 19, // 0 Entry should never be used
3055
3056 4, // 1 MinPriority
3057 3, // 2
3058 2, // 3
3059
3060 1, // 4
3061 0, // 5 NormPriority
3062 -1, // 6
3063
3064 -2, // 7
3065 -3, // 8
3066 -4, // 9 NearMaxPriority
3067
3068 -5 // 10 MaxPriority
3069 };
3070
3071 static int prio_init() {
3072 if (ThreadPriorityPolicy == 1) {
3073 // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
3074 // if effective uid is not root. Perhaps, a more elegant way of doing
3075 // this is to test CAP_SYS_NICE capability, but that will require libcap.so
3076 if (geteuid() != 0) {
3077 if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
3078 warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
3079 }
3080 ThreadPriorityPolicy = 0;
3081 }
3082 }
3083 return 0;
3084 }
3085
3086 OSReturn os::set_native_priority(Thread* thread, int newpri) {
3087 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
3088
3089 int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
3090 return (ret == 0) ? OS_OK : OS_ERR;
3091 }
3092
3093 OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
3094 if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
3095 *priority_ptr = java_to_os_priority[NormPriority];
3096 return OS_OK;
3097 }
3098
3099 errno = 0;
3100 *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
3101 return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
3102 }
3103
3104 // Hint to the underlying OS that a task switch would not be good.
3105 // Void return because it's a hint and can fail.
3106 void os::hint_no_preempt() {}
3107
3108 ////////////////////////////////////////////////////////////////////////////////
3109 // suspend/resume support
3110
3111 // the low-level signal-based suspend/resume support is a remnant from the
3112 // old VM-suspension that used to be for java-suspension, safepoints etc,
3113 // within hotspot. Now there is a single use-case for this:
3114 // - calling get_thread_pc() on the VMThread by the flat-profiler task
3115 // that runs in the watcher thread.
3116 // The remaining code is greatly simplified from the more general suspension
3117 // code that used to be used.
3118 //
3119 // The protocol is quite simple:
3120 // - suspend:
3121 // - sends a signal to the target thread
3122 // - polls the suspend state of the osthread using a yield loop
3123 // - target thread signal handler (SR_handler) sets suspend state
3124 // and blocks in sigsuspend until continued
3125 // - resume:
3126 // - sets target osthread state to continue
3127 // - sends signal to end the sigsuspend loop in the SR_handler
3128 //
3129 // Note that the SR_lock plays no role in this suspend/resume protocol.
3130 //
3131
3132 static void resume_clear_context(OSThread *osthread) {
3133 osthread->set_ucontext(NULL);
3134 osthread->set_siginfo(NULL);
3135
3136 // notify the suspend action is completed, we have now resumed
3137 osthread->sr.clear_suspended();
3138 }
3139
3140 static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
3141 osthread->set_ucontext(context);
3142 osthread->set_siginfo(siginfo);
3143 }
3144
3145 //
3146 // Handler function invoked when a thread's execution is suspended or
3147 // resumed. We have to be careful that only async-safe functions are
3148 // called here (Note: most pthread functions are not async safe and
3149 // should be avoided.)
3150 //
3151 // Note: sigwait() is a more natural fit than sigsuspend() from an
3152 // interface point of view, but sigwait() prevents the signal hander
3153 // from being run. libpthread would get very confused by not having
3154 // its signal handlers run and prevents sigwait()'s use with the
3155 // mutex granting granting signal.
3156 //
3157 // Currently only ever called on the VMThread
3158 //
3159 static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
3160 // Save and restore errno to avoid confusing native code with EINTR
3161 // after sigsuspend.
3162 int old_errno = errno;
3163
3164 Thread* thread = Thread::current();
3165 OSThread* osthread = thread->osthread();
3166 assert(thread->is_VM_thread(), "Must be VMThread");
3167 // read current suspend action
3168 int action = osthread->sr.suspend_action();
3169 if (action == SR_SUSPEND) {
3170 suspend_save_context(osthread, siginfo, context);
3171
3172 // Notify the suspend action is about to be completed. do_suspend()
3173 // waits until SR_SUSPENDED is set and then returns. We will wait
3174 // here for a resume signal and that completes the suspend-other
3175 // action. do_suspend/do_resume is always called as a pair from
3176 // the same thread - so there are no races
3177
3178 // notify the caller
3179 osthread->sr.set_suspended();
3180
3181 sigset_t suspend_set; // signals for sigsuspend()
3182
3183 // get current set of blocked signals and unblock resume signal
3184 pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
3185 sigdelset(&suspend_set, SR_signum);
3186
3187 // wait here until we are resumed
3188 do {
3189 sigsuspend(&suspend_set);
3190 // ignore all returns until we get a resume signal
3191 } while (osthread->sr.suspend_action() != SR_CONTINUE);
3192
3193 resume_clear_context(osthread);
3194
3195 } else {
3196 assert(action == SR_CONTINUE, "unexpected sr action");
3197 // nothing special to do - just leave the handler
3198 }
3199
3200 errno = old_errno;
3201 }
3202
3203
3204 static int SR_initialize() {
3205 struct sigaction act;
3206 char *s;
3207 /* Get signal number to use for suspend/resume */
3208 if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
3209 int sig = ::strtol(s, 0, 10);
3210 if (sig > 0 || sig < _NSIG) {
3211 SR_signum = sig;
3212 }
3213 }
3214
3215 assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
3216 "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
3217
3218 sigemptyset(&SR_sigset);
3219 sigaddset(&SR_sigset, SR_signum);
3220
3221 /* Set up signal handler for suspend/resume */
3222 act.sa_flags = SA_RESTART|SA_SIGINFO;
3223 act.sa_handler = (void (*)(int)) SR_handler;
3224
3225 // SR_signum is blocked by default.
3226 // 4528190 - We also need to block pthread restart signal (32 on all
3227 // supported Linux platforms). Note that LinuxThreads need to block
3228 // this signal for all threads to work properly. So we don't have
3229 // to use hard-coded signal number when setting up the mask.
3230 pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
3231
3232 if (sigaction(SR_signum, &act, 0) == -1) {
3233 return -1;
3234 }
3235
3236 // Save signal flag
3237 os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
3238 return 0;
3239 }
3240
3241 static int SR_finalize() {
3242 return 0;
3243 }
3244
3245
3246 // returns true on success and false on error - really an error is fatal
3247 // but this seems the normal response to library errors
3248 static bool do_suspend(OSThread* osthread) {
3249 // mark as suspended and send signal
3250 osthread->sr.set_suspend_action(SR_SUSPEND);
3251 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3252 assert_status(status == 0, status, "pthread_kill");
3253
3254 // check status and wait until notified of suspension
3255 if (status == 0) {
3256 for (int i = 0; !osthread->sr.is_suspended(); i++) {
3257 os::yield_all(i);
3258 }
3259 osthread->sr.set_suspend_action(SR_NONE);
3260 return true;
3261 }
3262 else {
3263 osthread->sr.set_suspend_action(SR_NONE);
3264 return false;
3265 }
3266 }
3267
3268 static void do_resume(OSThread* osthread) {
3269 assert(osthread->sr.is_suspended(), "thread should be suspended");
3270 osthread->sr.set_suspend_action(SR_CONTINUE);
3271
3272 int status = pthread_kill(osthread->pthread_id(), SR_signum);
3273 assert_status(status == 0, status, "pthread_kill");
3274 // check status and wait unit notified of resumption
3275 if (status == 0) {
3276 for (int i = 0; osthread->sr.is_suspended(); i++) {
3277 os::yield_all(i);
3278 }
3279 }
3280 osthread->sr.set_suspend_action(SR_NONE);
3281 }
3282
3283 ////////////////////////////////////////////////////////////////////////////////
3284 // interrupt support
3285
3286 void os::interrupt(Thread* thread) {
3287 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3288 "possibility of dangling Thread pointer");
3289
3290 OSThread* osthread = thread->osthread();
3291
3292 if (!osthread->interrupted()) {
3293 osthread->set_interrupted(true);
3294 // More than one thread can get here with the same value of osthread,
3295 // resulting in multiple notifications. We do, however, want the store
3296 // to interrupted() to be visible to other threads before we execute unpark().
3297 OrderAccess::fence();
3298 ParkEvent * const slp = thread->_SleepEvent ;
3299 if (slp != NULL) slp->unpark() ;
3300 }
3301
3302 // For JSR166. Unpark even if interrupt status already was set
3303 if (thread->is_Java_thread())
3304 ((JavaThread*)thread)->parker()->unpark();
3305
3306 ParkEvent * ev = thread->_ParkEvent ;
3307 if (ev != NULL) ev->unpark() ;
3308
3309 }
3310
3311 bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
3312 assert(Thread::current() == thread || Threads_lock->owned_by_self(),
3313 "possibility of dangling Thread pointer");
3314
3315 OSThread* osthread = thread->osthread();
3316
3317 bool interrupted = osthread->interrupted();
3318
3319 if (interrupted && clear_interrupted) {
3320 osthread->set_interrupted(false);
3321 // consider thread->_SleepEvent->reset() ... optional optimization
3322 }
3323
3324 return interrupted;
3325 }
3326
3327 ///////////////////////////////////////////////////////////////////////////////////
3328 // signal handling (except suspend/resume)
3329
3330 // This routine may be used by user applications as a "hook" to catch signals.
3331 // The user-defined signal handler must pass unrecognized signals to this
3332 // routine, and if it returns true (non-zero), then the signal handler must
3333 // return immediately. If the flag "abort_if_unrecognized" is true, then this
3334 // routine will never retun false (zero), but instead will execute a VM panic
3335 // routine kill the process.
3336 //
3337 // If this routine returns false, it is OK to call it again. This allows
3338 // the user-defined signal handler to perform checks either before or after
3339 // the VM performs its own checks. Naturally, the user code would be making
3340 // a serious error if it tried to handle an exception (such as a null check
3341 // or breakpoint) that the VM was generating for its own correct operation.
3342 //
3343 // This routine may recognize any of the following kinds of signals:
3344 // SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
3345 // It should be consulted by handlers for any of those signals.
3346 //
3347 // The caller of this routine must pass in the three arguments supplied
3348 // to the function referred to in the "sa_sigaction" (not the "sa_handler")
3349 // field of the structure passed to sigaction(). This routine assumes that
3350 // the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
3351 //
3352 // Note that the VM will print warnings if it detects conflicting signal
3353 // handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
3354 //
3355 extern "C" int
3356 JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
3357 void* ucontext, int abort_if_unrecognized);
3358
3359 void signalHandler(int sig, siginfo_t* info, void* uc) {
3360 assert(info != NULL && uc != NULL, "it must be old kernel");
3361 JVM_handle_linux_signal(sig, info, uc, true);
3362 }
3363
3364
3365 // This boolean allows users to forward their own non-matching signals
3366 // to JVM_handle_linux_signal, harmlessly.
3367 bool os::Linux::signal_handlers_are_installed = false;
3368
3369 // For signal-chaining
3370 struct sigaction os::Linux::sigact[MAXSIGNUM];
3371 unsigned int os::Linux::sigs = 0;
3372 bool os::Linux::libjsig_is_loaded = false;
3373 typedef struct sigaction *(*get_signal_t)(int);
3374 get_signal_t os::Linux::get_signal_action = NULL;
3375
3376 struct sigaction* os::Linux::get_chained_signal_action(int sig) {
3377 struct sigaction *actp = NULL;
3378
3379 if (libjsig_is_loaded) {
3380 // Retrieve the old signal handler from libjsig
3381 actp = (*get_signal_action)(sig);
3382 }
3383 if (actp == NULL) {
3384 // Retrieve the preinstalled signal handler from jvm
3385 actp = get_preinstalled_handler(sig);
3386 }
3387
3388 return actp;
3389 }
3390
3391 static bool call_chained_handler(struct sigaction *actp, int sig,
3392 siginfo_t *siginfo, void *context) {
3393 // Call the old signal handler
3394 if (actp->sa_handler == SIG_DFL) {
3395 // It's more reasonable to let jvm treat it as an unexpected exception
3396 // instead of taking the default action.
3397 return false;
3398 } else if (actp->sa_handler != SIG_IGN) {
3399 if ((actp->sa_flags & SA_NODEFER) == 0) {
3400 // automaticlly block the signal
3401 sigaddset(&(actp->sa_mask), sig);
3402 }
3403
3404 sa_handler_t hand;
3405 sa_sigaction_t sa;
3406 bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
3407 // retrieve the chained handler
3408 if (siginfo_flag_set) {
3409 sa = actp->sa_sigaction;
3410 } else {
3411 hand = actp->sa_handler;
3412 }
3413
3414 if ((actp->sa_flags & SA_RESETHAND) != 0) {
3415 actp->sa_handler = SIG_DFL;
3416 }
3417
3418 // try to honor the signal mask
3419 sigset_t oset;
3420 pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
3421
3422 // call into the chained handler
3423 if (siginfo_flag_set) {
3424 (*sa)(sig, siginfo, context);
3425 } else {
3426 (*hand)(sig);
3427 }
3428
3429 // restore the signal mask
3430 pthread_sigmask(SIG_SETMASK, &oset, 0);
3431 }
3432 // Tell jvm's signal handler the signal is taken care of.
3433 return true;
3434 }
3435
3436 bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
3437 bool chained = false;
3438 // signal-chaining
3439 if (UseSignalChaining) {
3440 struct sigaction *actp = get_chained_signal_action(sig);
3441 if (actp != NULL) {
3442 chained = call_chained_handler(actp, sig, siginfo, context);
3443 }
3444 }
3445 return chained;
3446 }
3447
3448 struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
3449 if ((( (unsigned int)1 << sig ) & sigs) != 0) {
3450 return &sigact[sig];
3451 }
3452 return NULL;
3453 }
3454
3455 void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
3456 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3457 sigact[sig] = oldAct;
3458 sigs |= (unsigned int)1 << sig;
3459 }
3460
3461 // for diagnostic
3462 int os::Linux::sigflags[MAXSIGNUM];
3463
3464 int os::Linux::get_our_sigflags(int sig) {
3465 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3466 return sigflags[sig];
3467 }
3468
3469 void os::Linux::set_our_sigflags(int sig, int flags) {
3470 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3471 sigflags[sig] = flags;
3472 }
3473
3474 void os::Linux::set_signal_handler(int sig, bool set_installed) {
3475 // Check for overwrite.
3476 struct sigaction oldAct;
3477 sigaction(sig, (struct sigaction*)NULL, &oldAct);
3478
3479 void* oldhand = oldAct.sa_sigaction
3480 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3481 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3482 if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
3483 oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
3484 oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
3485 if (AllowUserSignalHandlers || !set_installed) {
3486 // Do not overwrite; user takes responsibility to forward to us.
3487 return;
3488 } else if (UseSignalChaining) {
3489 // save the old handler in jvm
3490 save_preinstalled_handler(sig, oldAct);
3491 // libjsig also interposes the sigaction() call below and saves the
3492 // old sigaction on it own.
3493 } else {
3494 fatal2("Encountered unexpected pre-existing sigaction handler %#lx for signal %d.", (long)oldhand, sig);
3495 }
3496 }
3497
3498 struct sigaction sigAct;
3499 sigfillset(&(sigAct.sa_mask));
3500 sigAct.sa_handler = SIG_DFL;
3501 if (!set_installed) {
3502 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3503 } else {
3504 sigAct.sa_sigaction = signalHandler;
3505 sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
3506 }
3507 // Save flags, which are set by ours
3508 assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
3509 sigflags[sig] = sigAct.sa_flags;
3510
3511 int ret = sigaction(sig, &sigAct, &oldAct);
3512 assert(ret == 0, "check");
3513
3514 void* oldhand2 = oldAct.sa_sigaction
3515 ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
3516 : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
3517 assert(oldhand2 == oldhand, "no concurrent signal handler installation");
3518 }
3519
3520 // install signal handlers for signals that HotSpot needs to
3521 // handle in order to support Java-level exception handling.
3522
3523 void os::Linux::install_signal_handlers() {
3524 if (!signal_handlers_are_installed) {
3525 signal_handlers_are_installed = true;
3526
3527 // signal-chaining
3528 typedef void (*signal_setting_t)();
3529 signal_setting_t begin_signal_setting = NULL;
3530 signal_setting_t end_signal_setting = NULL;
3531 begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3532 dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
3533 if (begin_signal_setting != NULL) {
3534 end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
3535 dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
3536 get_signal_action = CAST_TO_FN_PTR(get_signal_t,
3537 dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
3538 libjsig_is_loaded = true;
3539 assert(UseSignalChaining, "should enable signal-chaining");
3540 }
3541 if (libjsig_is_loaded) {
3542 // Tell libjsig jvm is setting signal handlers
3543 (*begin_signal_setting)();
3544 }
3545
3546 set_signal_handler(SIGSEGV, true);
3547 set_signal_handler(SIGPIPE, true);
3548 set_signal_handler(SIGBUS, true);
3549 set_signal_handler(SIGILL, true);
3550 set_signal_handler(SIGFPE, true);
3551 set_signal_handler(SIGXFSZ, true);
3552
3553 if (libjsig_is_loaded) {
3554 // Tell libjsig jvm finishes setting signal handlers
3555 (*end_signal_setting)();
3556 }
3557
3558 // We don't activate signal checker if libjsig is in place, we trust ourselves
3559 // and if UserSignalHandler is installed all bets are off
3560 if (CheckJNICalls) {
3561 if (libjsig_is_loaded) {
3562 tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
3563 check_signals = false;
3564 }
3565 if (AllowUserSignalHandlers) {
3566 tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
3567 check_signals = false;
3568 }
3569 }
3570 }
3571 }
3572
3573 // This is the fastest way to get thread cpu time on Linux.
3574 // Returns cpu time (user+sys) for any thread, not only for current.
3575 // POSIX compliant clocks are implemented in the kernels 2.6.16+.
3576 // It might work on 2.6.10+ with a special kernel/glibc patch.
3577 // For reference, please, see IEEE Std 1003.1-2004:
3578 // http://www.unix.org/single_unix_specification
3579
3580 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
3581 struct timespec tp;
3582 int rc = os::Linux::clock_gettime(clockid, &tp);
3583 assert(rc == 0, "clock_gettime is expected to return 0 code");
3584
3585 return (tp.tv_sec * SEC_IN_NANOSECS) + tp.tv_nsec;
3586 }
3587
3588 /////
3589 // glibc on Linux platform uses non-documented flag
3590 // to indicate, that some special sort of signal
3591 // trampoline is used.
3592 // We will never set this flag, and we should
3593 // ignore this flag in our diagnostic
3594 #ifdef SIGNIFICANT_SIGNAL_MASK
3595 #undef SIGNIFICANT_SIGNAL_MASK
3596 #endif
3597 #define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
3598
3599 static const char* get_signal_handler_name(address handler,
3600 char* buf, int buflen) {
3601 int offset;
3602 bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
3603 if (found) {
3604 // skip directory names
3605 const char *p1, *p2;
3606 p1 = buf;
3607 size_t len = strlen(os::file_separator());
3608 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
3609 jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
3610 } else {
3611 jio_snprintf(buf, buflen, PTR_FORMAT, handler);
3612 }
3613 return buf;
3614 }
3615
3616 static void print_signal_handler(outputStream* st, int sig,
3617 char* buf, size_t buflen) {
3618 struct sigaction sa;
3619
3620 sigaction(sig, NULL, &sa);
3621
3622 // See comment for SIGNIFICANT_SIGNAL_MASK define
3623 sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3624
3625 st->print("%s: ", os::exception_name(sig, buf, buflen));
3626
3627 address handler = (sa.sa_flags & SA_SIGINFO)
3628 ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
3629 : CAST_FROM_FN_PTR(address, sa.sa_handler);
3630
3631 if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
3632 st->print("SIG_DFL");
3633 } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
3634 st->print("SIG_IGN");
3635 } else {
3636 st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
3637 }
3638
3639 st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask);
3640
3641 address rh = VMError::get_resetted_sighandler(sig);
3642 // May be, handler was resetted by VMError?
3643 if(rh != NULL) {
3644 handler = rh;
3645 sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
3646 }
3647
3648 st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags);
3649
3650 // Check: is it our handler?
3651 if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
3652 handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
3653 // It is our signal handler
3654 // check for flags, reset system-used one!
3655 if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
3656 st->print(
3657 ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
3658 os::Linux::get_our_sigflags(sig));
3659 }
3660 }
3661 st->cr();
3662 }
3663
3664
3665 #define DO_SIGNAL_CHECK(sig) \
3666 if (!sigismember(&check_signal_done, sig)) \
3667 os::Linux::check_signal_handler(sig)
3668
3669 // This method is a periodic task to check for misbehaving JNI applications
3670 // under CheckJNI, we can add any periodic checks here
3671
3672 void os::run_periodic_checks() {
3673
3674 if (check_signals == false) return;
3675
3676 // SEGV and BUS if overridden could potentially prevent
3677 // generation of hs*.log in the event of a crash, debugging
3678 // such a case can be very challenging, so we absolutely
3679 // check the following for a good measure:
3680 DO_SIGNAL_CHECK(SIGSEGV);
3681 DO_SIGNAL_CHECK(SIGILL);
3682 DO_SIGNAL_CHECK(SIGFPE);
3683 DO_SIGNAL_CHECK(SIGBUS);
3684 DO_SIGNAL_CHECK(SIGPIPE);
3685 DO_SIGNAL_CHECK(SIGXFSZ);
3686
3687
3688 // ReduceSignalUsage allows the user to override these handlers
3689 // see comments at the very top and jvm_solaris.h
3690 if (!ReduceSignalUsage) {
3691 DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
3692 DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
3693 DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
3694 DO_SIGNAL_CHECK(BREAK_SIGNAL);
3695 }
3696
3697 DO_SIGNAL_CHECK(SR_signum);
3698 DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
3699 }
3700
3701 typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
3702
3703 static os_sigaction_t os_sigaction = NULL;
3704
3705 void os::Linux::check_signal_handler(int sig) {
3706 char buf[O_BUFLEN];
3707 address jvmHandler = NULL;
3708
3709
3710 struct sigaction act;
3711 if (os_sigaction == NULL) {
3712 // only trust the default sigaction, in case it has been interposed
3713 os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
3714 if (os_sigaction == NULL) return;
3715 }
3716
3717 os_sigaction(sig, (struct sigaction*)NULL, &act);
3718
3719
3720 act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
3721
3722 address thisHandler = (act.sa_flags & SA_SIGINFO)
3723 ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
3724 : CAST_FROM_FN_PTR(address, act.sa_handler) ;
3725
3726
3727 switch(sig) {
3728 case SIGSEGV:
3729 case SIGBUS:
3730 case SIGFPE:
3731 case SIGPIPE:
3732 case SIGILL:
3733 case SIGXFSZ:
3734 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
3735 break;
3736
3737 case SHUTDOWN1_SIGNAL:
3738 case SHUTDOWN2_SIGNAL:
3739 case SHUTDOWN3_SIGNAL:
3740 case BREAK_SIGNAL:
3741 jvmHandler = (address)user_handler();
3742 break;
3743
3744 case INTERRUPT_SIGNAL:
3745 jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
3746 break;
3747
3748 default:
3749 if (sig == SR_signum) {
3750 jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
3751 } else {
3752 return;
3753 }
3754 break;
3755 }
3756
3757 if (thisHandler != jvmHandler) {
3758 tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
3759 tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
3760 tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
3761 // No need to check this sig any longer
3762 sigaddset(&check_signal_done, sig);
3763 } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
3764 tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
3765 tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
3766 tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
3767 // No need to check this sig any longer
3768 sigaddset(&check_signal_done, sig);
3769 }
3770
3771 // Dump all the signal
3772 if (sigismember(&check_signal_done, sig)) {
3773 print_signal_handlers(tty, buf, O_BUFLEN);
3774 }
3775 }
3776
3777 extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
3778
3779 extern bool signal_name(int signo, char* buf, size_t len);
3780
3781 const char* os::exception_name(int exception_code, char* buf, size_t size) {
3782 if (0 < exception_code && exception_code <= SIGRTMAX) {
3783 // signal
3784 if (!signal_name(exception_code, buf, size)) {
3785 jio_snprintf(buf, size, "SIG%d", exception_code);
3786 }
3787 return buf;
3788 } else {
3789 return NULL;
3790 }
3791 }
3792
3793 // this is called _before_ the most of global arguments have been parsed
3794 void os::init(void) {
3795 char dummy; /* used to get a guess on initial stack address */
3796 // first_hrtime = gethrtime();
3797
3798 // With LinuxThreads the JavaMain thread pid (primordial thread)
3799 // is different than the pid of the java launcher thread.
3800 // So, on Linux, the launcher thread pid is passed to the VM
3801 // via the sun.java.launcher.pid property.
3802 // Use this property instead of getpid() if it was correctly passed.
3803 // See bug 6351349.
3804 pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
3805
3806 _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
3807
3808 clock_tics_per_sec = sysconf(_SC_CLK_TCK);
3809
3810 init_random(1234567);
3811
3812 ThreadCritical::initialize();
3813
3814 Linux::set_page_size(sysconf(_SC_PAGESIZE));
3815 if (Linux::page_size() == -1) {
3816 fatal1("os_linux.cpp: os::init: sysconf failed (%s)", strerror(errno));
3817 }
3818 init_page_sizes((size_t) Linux::page_size());
3819
3820 Linux::initialize_system_info();
3821
3822 // main_thread points to the aboriginal thread
3823 Linux::_main_thread = pthread_self();
3824
3825 Linux::clock_init();
3826 initial_time_count = os::elapsed_counter();
3827 pthread_mutex_init(&dl_mutex, NULL);
3828 }
3829
3830 // To install functions for atexit system call
3831 extern "C" {
3832 static void perfMemory_exit_helper() {
3833 perfMemory_exit();
3834 }
3835 }
3836
3837 // this is called _after_ the global arguments have been parsed
3838 jint os::init_2(void)
3839 {
3840 Linux::fast_thread_clock_init();
3841
3842 // Allocate a single page and mark it as readable for safepoint polling
3843 address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
3844 guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
3845
3846 os::set_polling_page( polling_page );
3847
3848 #ifndef PRODUCT
3849 if(Verbose && PrintMiscellaneous)
3850 tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
3851 #endif
3852
3853 if (!UseMembar) {
3854 address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
3855 guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page");
3856 os::set_memory_serialize_page( mem_serialize_page );
3857
3858 #ifndef PRODUCT
3859 if(Verbose && PrintMiscellaneous)
3860 tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
3861 #endif
3862 }
3863
3864 FLAG_SET_DEFAULT(UseLargePages, os::large_page_init());
3865
3866 // initialize suspend/resume support - must do this before signal_sets_init()
3867 if (SR_initialize() != 0) {
3868 perror("SR_initialize failed");
3869 return JNI_ERR;
3870 }
3871
3872 Linux::signal_sets_init();
3873 Linux::install_signal_handlers();
3874
3875 size_t threadStackSizeInBytes = ThreadStackSize * K;
3876 if (threadStackSizeInBytes != 0 &&
3877 threadStackSizeInBytes < Linux::min_stack_allowed) {
3878 tty->print_cr("\nThe stack size specified is too small, "
3879 "Specify at least %dk",
3880 Linux::min_stack_allowed / K);
3881 return JNI_ERR;
3882 }
3883
3884 // Make the stack size a multiple of the page size so that
3885 // the yellow/red zones can be guarded.
3886 JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
3887 vm_page_size()));
3888
3889 Linux::capture_initial_stack(JavaThread::stack_size_at_create());
3890
3891 Linux::libpthread_init();
3892 if (PrintMiscellaneous && (Verbose || WizardMode)) {
3893 tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
3894 Linux::glibc_version(), Linux::libpthread_version(),
3895 Linux::is_floating_stack() ? "floating stack" : "fixed stack");
3896 }
3897
3898 if (UseNUMA) {
3899 if (!Linux::libnuma_init()) {
3900 UseNUMA = false;
3901 } else {
3902 if ((Linux::numa_max_node() < 1)) {
3903 // There's only one node(they start from 0), disable NUMA.
3904 UseNUMA = false;
3905 }
3906 }
3907 if (!UseNUMA && ForceNUMA) {
3908 UseNUMA = true;
3909 }
3910 }
3911
3912 if (MaxFDLimit) {
3913 // set the number of file descriptors to max. print out error
3914 // if getrlimit/setrlimit fails but continue regardless.
3915 struct rlimit nbr_files;
3916 int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
3917 if (status != 0) {
3918 if (PrintMiscellaneous && (Verbose || WizardMode))
3919 perror("os::init_2 getrlimit failed");
3920 } else {
3921 nbr_files.rlim_cur = nbr_files.rlim_max;
3922 status = setrlimit(RLIMIT_NOFILE, &nbr_files);
3923 if (status != 0) {
3924 if (PrintMiscellaneous && (Verbose || WizardMode))
3925 perror("os::init_2 setrlimit failed");
3926 }
3927 }
3928 }
3929
3930 // Initialize lock used to serialize thread creation (see os::create_thread)
3931 Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
3932
3933 // Initialize HPI.
3934 jint hpi_result = hpi::initialize();
3935 if (hpi_result != JNI_OK) {
3936 tty->print_cr("There was an error trying to initialize the HPI library.");
3937 return hpi_result;
3938 }
3939
3940 // at-exit methods are called in the reverse order of their registration.
3941 // atexit functions are called on return from main or as a result of a
3942 // call to exit(3C). There can be only 32 of these functions registered
3943 // and atexit() does not set errno.
3944
3945 if (PerfAllowAtExitRegistration) {
3946 // only register atexit functions if PerfAllowAtExitRegistration is set.
3947 // atexit functions can be delayed until process exit time, which
3948 // can be problematic for embedded VM situations. Embedded VMs should
3949 // call DestroyJavaVM() to assure that VM resources are released.
3950
3951 // note: perfMemory_exit_helper atexit function may be removed in
3952 // the future if the appropriate cleanup code can be added to the
3953 // VM_Exit VMOperation's doit method.
3954 if (atexit(perfMemory_exit_helper) != 0) {
3955 warning("os::init2 atexit(perfMemory_exit_helper) failed");
3956 }
3957 }
3958
3959 // initialize thread priority policy
3960 prio_init();
3961
3962 return JNI_OK;
3963 }
3964
3965 // Mark the polling page as unreadable
3966 void os::make_polling_page_unreadable(void) {
3967 if( !guard_memory((char*)_polling_page, Linux::page_size()) )
3968 fatal("Could not disable polling page");
3969 };
3970
3971 // Mark the polling page as readable
3972 void os::make_polling_page_readable(void) {
3973 if( !linux_mprotect((char *)_polling_page, Linux::page_size(), PROT_READ)) {
3974 fatal("Could not enable polling page");
3975 }
3976 };
3977
3978 int os::active_processor_count() {
3979 // Linux doesn't yet have a (official) notion of processor sets,
3980 // so just return the number of online processors.
3981 int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
3982 assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
3983 return online_cpus;
3984 }
3985
3986 bool os::distribute_processes(uint length, uint* distribution) {
3987 // Not yet implemented.
3988 return false;
3989 }
3990
3991 bool os::bind_to_processor(uint processor_id) {
3992 // Not yet implemented.
3993 return false;
3994 }
3995
3996 ///
3997
3998 // Suspends the target using the signal mechanism and then grabs the PC before
3999 // resuming the target. Used by the flat-profiler only
4000 ExtendedPC os::get_thread_pc(Thread* thread) {
4001 // Make sure that it is called by the watcher for the VMThread
4002 assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
4003 assert(thread->is_VM_thread(), "Can only be called for VMThread");
4004
4005 ExtendedPC epc;
4006
4007 OSThread* osthread = thread->osthread();
4008 if (do_suspend(osthread)) {
4009 if (osthread->ucontext() != NULL) {
4010 epc = os::Linux::ucontext_get_pc(osthread->ucontext());
4011 } else {
4012 // NULL context is unexpected, double-check this is the VMThread
4013 guarantee(thread->is_VM_thread(), "can only be called for VMThread");
4014 }
4015 do_resume(osthread);
4016 }
4017 // failure means pthread_kill failed for some reason - arguably this is
4018 // a fatal problem, but such problems are ignored elsewhere
4019
4020 return epc;
4021 }
4022
4023 int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
4024 {
4025 if (is_NPTL()) {
4026 return pthread_cond_timedwait(_cond, _mutex, _abstime);
4027 } else {
4028 #ifndef IA64
4029 // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
4030 // word back to default 64bit precision if condvar is signaled. Java
4031 // wants 53bit precision. Save and restore current value.
4032 int fpu = get_fpu_control_word();
4033 #endif // IA64
4034 int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
4035 #ifndef IA64
4036 set_fpu_control_word(fpu);
4037 #endif // IA64
4038 return status;
4039 }
4040 }
4041
4042 ////////////////////////////////////////////////////////////////////////////////
4043 // debug support
4044
4045 #ifndef PRODUCT
4046 static address same_page(address x, address y) {
4047 int page_bits = -os::vm_page_size();
4048 if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits))
4049 return x;
4050 else if (x > y)
4051 return (address)(intptr_t(y) | ~page_bits) + 1;
4052 else
4053 return (address)(intptr_t(y) & page_bits);
4054 }
4055
4056 bool os::find(address addr) {
4057 Dl_info dlinfo;
4058 memset(&dlinfo, 0, sizeof(dlinfo));
4059 if (dladdr(addr, &dlinfo)) {
4060 tty->print(PTR_FORMAT ": ", addr);
4061 if (dlinfo.dli_sname != NULL) {
4062 tty->print("%s+%#x", dlinfo.dli_sname,
4063 addr - (intptr_t)dlinfo.dli_saddr);
4064 } else if (dlinfo.dli_fname) {
4065 tty->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
4066 } else {
4067 tty->print("<absolute address>");
4068 }
4069 if (dlinfo.dli_fname) {
4070 tty->print(" in %s", dlinfo.dli_fname);
4071 }
4072 if (dlinfo.dli_fbase) {
4073 tty->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
4074 }
4075 tty->cr();
4076
4077 if (Verbose) {
4078 // decode some bytes around the PC
4079 address begin = same_page(addr-40, addr);
4080 address end = same_page(addr+40, addr);
4081 address lowest = (address) dlinfo.dli_sname;
4082 if (!lowest) lowest = (address) dlinfo.dli_fbase;
4083 if (begin < lowest) begin = lowest;
4084 Dl_info dlinfo2;
4085 if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr
4086 && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
4087 end = (address) dlinfo2.dli_saddr;
4088 Disassembler::decode(begin, end);
4089 }
4090 return true;
4091 }
4092 return false;
4093 }
4094
4095 #endif
4096
4097 ////////////////////////////////////////////////////////////////////////////////
4098 // misc
4099
4100 // This does not do anything on Linux. This is basically a hook for being
4101 // able to use structured exception handling (thread-local exception filters)
4102 // on, e.g., Win32.
4103 void
4104 os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
4105 JavaCallArguments* args, Thread* thread) {
4106 f(value, method, args, thread);
4107 }
4108
4109 void os::print_statistics() {
4110 }
4111
4112 int os::message_box(const char* title, const char* message) {
4113 int i;
4114 fdStream err(defaultStream::error_fd());
4115 for (i = 0; i < 78; i++) err.print_raw("=");
4116 err.cr();
4117 err.print_raw_cr(title);
4118 for (i = 0; i < 78; i++) err.print_raw("-");
4119 err.cr();
4120 err.print_raw_cr(message);
4121 for (i = 0; i < 78; i++) err.print_raw("=");
4122 err.cr();
4123
4124 char buf[16];
4125 // Prevent process from exiting upon "read error" without consuming all CPU
4126 while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
4127
4128 return buf[0] == 'y' || buf[0] == 'Y';
4129 }
4130
4131 int os::stat(const char *path, struct stat *sbuf) {
4132 char pathbuf[MAX_PATH];
4133 if (strlen(path) > MAX_PATH - 1) {
4134 errno = ENAMETOOLONG;
4135 return -1;
4136 }
4137 hpi::native_path(strcpy(pathbuf, path));
4138 return ::stat(pathbuf, sbuf);
4139 }
4140
4141 bool os::check_heap(bool force) {
4142 return true;
4143 }
4144
4145 int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
4146 return ::vsnprintf(buf, count, format, args);
4147 }
4148
4149 // Is a (classpath) directory empty?
4150 bool os::dir_is_empty(const char* path) {
4151 DIR *dir = NULL;
4152 struct dirent *ptr;
4153
4154 dir = opendir(path);
4155 if (dir == NULL) return true;
4156
4157 /* Scan the directory */
4158 bool result = true;
4159 char buf[sizeof(struct dirent) + MAX_PATH];
4160 while (result && (ptr = ::readdir(dir)) != NULL) {
4161 if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
4162 result = false;
4163 }
4164 }
4165 closedir(dir);
4166 return result;
4167 }
4168
4169 // create binary file, rewriting existing file if required
4170 int os::create_binary_file(const char* path, bool rewrite_existing) {
4171 int oflags = O_WRONLY | O_CREAT;
4172 if (!rewrite_existing) {
4173 oflags |= O_EXCL;
4174 }
4175 return ::open64(path, oflags, S_IREAD | S_IWRITE);
4176 }
4177
4178 // return current position of file pointer
4179 jlong os::current_file_offset(int fd) {
4180 return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
4181 }
4182
4183 // move file pointer to the specified offset
4184 jlong os::seek_to_file_offset(int fd, jlong offset) {
4185 return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
4186 }
4187
4188 // Map a block of memory.
4189 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
4190 char *addr, size_t bytes, bool read_only,
4191 bool allow_exec) {
4192 int prot;
4193 int flags;
4194
4195 if (read_only) {
4196 prot = PROT_READ;
4197 flags = MAP_SHARED;
4198 } else {
4199 prot = PROT_READ | PROT_WRITE;
4200 flags = MAP_PRIVATE;
4201 }
4202
4203 if (allow_exec) {
4204 prot |= PROT_EXEC;
4205 }
4206
4207 if (addr != NULL) {
4208 flags |= MAP_FIXED;
4209 }
4210
4211 char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
4212 fd, file_offset);
4213 if (mapped_address == MAP_FAILED) {
4214 return NULL;
4215 }
4216 return mapped_address;
4217 }
4218
4219
4220 // Remap a block of memory.
4221 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
4222 char *addr, size_t bytes, bool read_only,
4223 bool allow_exec) {
4224 // same as map_memory() on this OS
4225 return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
4226 allow_exec);
4227 }
4228
4229
4230 // Unmap a block of memory.
4231 bool os::unmap_memory(char* addr, size_t bytes) {
4232 return munmap(addr, bytes) == 0;
4233 }
4234
4235 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
4236
4237 static clockid_t thread_cpu_clockid(Thread* thread) {
4238 pthread_t tid = thread->osthread()->pthread_id();
4239 clockid_t clockid;
4240
4241 // Get thread clockid
4242 int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
4243 assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
4244 return clockid;
4245 }
4246
4247 // current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
4248 // are used by JVM M&M and JVMTI to get user+sys or user CPU time
4249 // of a thread.
4250 //
4251 // current_thread_cpu_time() and thread_cpu_time(Thread*) returns
4252 // the fast estimate available on the platform.
4253
4254 jlong os::current_thread_cpu_time() {
4255 if (os::Linux::supports_fast_thread_cpu_time()) {
4256 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4257 } else {
4258 // return user + sys since the cost is the same
4259 return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
4260 }
4261 }
4262
4263 jlong os::thread_cpu_time(Thread* thread) {
4264 // consistent with what current_thread_cpu_time() returns
4265 if (os::Linux::supports_fast_thread_cpu_time()) {
4266 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4267 } else {
4268 return slow_thread_cpu_time(thread, true /* user + sys */);
4269 }
4270 }
4271
4272 jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
4273 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4274 return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
4275 } else {
4276 return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
4277 }
4278 }
4279
4280 jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4281 if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
4282 return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
4283 } else {
4284 return slow_thread_cpu_time(thread, user_sys_cpu_time);
4285 }
4286 }
4287
4288 //
4289 // -1 on error.
4290 //
4291
4292 static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
4293 static bool proc_pid_cpu_avail = true;
4294 static bool proc_task_unchecked = true;
4295 static const char *proc_stat_path = "/proc/%d/stat";
4296 pid_t tid = thread->osthread()->thread_id();
4297 int i;
4298 char *s;
4299 char stat[2048];
4300 int statlen;
4301 char proc_name[64];
4302 int count;
4303 long sys_time, user_time;
4304 char string[64];
4305 int idummy;
4306 long ldummy;
4307 FILE *fp;
4308
4309 // We first try accessing /proc/<pid>/cpu since this is faster to
4310 // process. If this file is not present (linux kernels 2.5 and above)
4311 // then we open /proc/<pid>/stat.
4312 if ( proc_pid_cpu_avail ) {
4313 sprintf(proc_name, "/proc/%d/cpu", tid);
4314 fp = fopen(proc_name, "r");
4315 if ( fp != NULL ) {
4316 count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time);
4317 fclose(fp);
4318 if ( count != 3 ) return -1;
4319
4320 if (user_sys_cpu_time) {
4321 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4322 } else {
4323 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4324 }
4325 }
4326 else proc_pid_cpu_avail = false;
4327 }
4328
4329 // The /proc/<tid>/stat aggregates per-process usage on
4330 // new Linux kernels 2.6+ where NPTL is supported.
4331 // The /proc/self/task/<tid>/stat still has the per-thread usage.
4332 // See bug 6328462.
4333 // There can be no directory /proc/self/task on kernels 2.4 with NPTL
4334 // and possibly in some other cases, so we check its availability.
4335 if (proc_task_unchecked && os::Linux::is_NPTL()) {
4336 // This is executed only once
4337 proc_task_unchecked = false;
4338 fp = fopen("/proc/self/task", "r");
4339 if (fp != NULL) {
4340 proc_stat_path = "/proc/self/task/%d/stat";
4341 fclose(fp);
4342 }
4343 }
4344
4345 sprintf(proc_name, proc_stat_path, tid);
4346 fp = fopen(proc_name, "r");
4347 if ( fp == NULL ) return -1;
4348 statlen = fread(stat, 1, 2047, fp);
4349 stat[statlen] = '\0';
4350 fclose(fp);
4351
4352 // Skip pid and the command string. Note that we could be dealing with
4353 // weird command names, e.g. user could decide to rename java launcher
4354 // to "java 1.4.2 :)", then the stat file would look like
4355 // 1234 (java 1.4.2 :)) R ... ...
4356 // We don't really need to know the command string, just find the last
4357 // occurrence of ")" and then start parsing from there. See bug 4726580.
4358 s = strrchr(stat, ')');
4359 i = 0;
4360 if (s == NULL ) return -1;
4361
4362 // Skip blank chars
4363 do s++; while (isspace(*s));
4364
4365 count = sscanf(s,"%*c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
4366 &idummy, &idummy, &idummy, &idummy, &idummy,
4367 &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
4368 &user_time, &sys_time);
4369 if ( count != 12 ) return -1;
4370 if (user_sys_cpu_time) {
4371 return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
4372 } else {
4373 return (jlong)user_time * (1000000000 / clock_tics_per_sec);
4374 }
4375 }
4376
4377 void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4378 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4379 info_ptr->may_skip_backward = false; // elapsed time not wall time
4380 info_ptr->may_skip_forward = false; // elapsed time not wall time
4381 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4382 }
4383
4384 void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
4385 info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
4386 info_ptr->may_skip_backward = false; // elapsed time not wall time
4387 info_ptr->may_skip_forward = false; // elapsed time not wall time
4388 info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
4389 }
4390
4391 bool os::is_thread_cpu_time_supported() {
4392 return true;
4393 }
4394
4395 // System loadavg support. Returns -1 if load average cannot be obtained.
4396 // Linux doesn't yet have a (official) notion of processor sets,
4397 // so just return the system wide load average.
4398 int os::loadavg(double loadavg[], int nelem) {
4399 return ::getloadavg(loadavg, nelem);
4400 }
4401
4402 void os::pause() {
4403 char filename[MAX_PATH];
4404 if (PauseAtStartupFile && PauseAtStartupFile[0]) {
4405 jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
4406 } else {
4407 jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
4408 }
4409
4410 int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
4411 if (fd != -1) {
4412 struct stat buf;
4413 close(fd);
4414 while (::stat(filename, &buf) == 0) {
4415 (void)::poll(NULL, 0, 100);
4416 }
4417 } else {
4418 jio_fprintf(stderr,
4419 "Could not open pause file '%s', continuing immediately.\n", filename);
4420 }
4421 }
4422
4423 extern "C" {
4424
4425 /**
4426 * NOTE: the following code is to keep the green threads code
4427 * in the libjava.so happy. Once the green threads is removed,
4428 * these code will no longer be needed.
4429 */
4430 int
4431 jdk_waitpid(pid_t pid, int* status, int options) {
4432 return waitpid(pid, status, options);
4433 }
4434
4435 int
4436 fork1() {
4437 return fork();
4438 }
4439
4440 int
4441 jdk_sem_init(sem_t *sem, int pshared, unsigned int value) {
4442 return sem_init(sem, pshared, value);
4443 }
4444
4445 int
4446 jdk_sem_post(sem_t *sem) {
4447 return sem_post(sem);
4448 }
4449
4450 int
4451 jdk_sem_wait(sem_t *sem) {
4452 return sem_wait(sem);
4453 }
4454
4455 int
4456 jdk_pthread_sigmask(int how , const sigset_t* newmask, sigset_t* oldmask) {
4457 return pthread_sigmask(how , newmask, oldmask);
4458 }
4459
4460 }
4461
4462 // Refer to the comments in os_solaris.cpp park-unpark.
4463 //
4464 // Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
4465 // hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
4466 // For specifics regarding the bug see GLIBC BUGID 261237 :
4467 // http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
4468 // Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
4469 // will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
4470 // is used. (The simple C test-case provided in the GLIBC bug report manifests the
4471 // hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
4472 // and monitorenter when we're using 1-0 locking. All those operations may result in
4473 // calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
4474 // of libpthread avoids the problem, but isn't practical.
4475 //
4476 // Possible remedies:
4477 //
4478 // 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
4479 // This is palliative and probabilistic, however. If the thread is preempted
4480 // between the call to compute_abstime() and pthread_cond_timedwait(), more
4481 // than the minimum period may have passed, and the abstime may be stale (in the
4482 // past) resultin in a hang. Using this technique reduces the odds of a hang
4483 // but the JVM is still vulnerable, particularly on heavily loaded systems.
4484 //
4485 // 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
4486 // of the usual flag-condvar-mutex idiom. The write side of the pipe is set
4487 // NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
4488 // reduces to poll()+read(). This works well, but consumes 2 FDs per extant
4489 // thread.
4490 //
4491 // 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
4492 // that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
4493 // a timeout request to the chron thread and then blocking via pthread_cond_wait().
4494 // This also works well. In fact it avoids kernel-level scalability impediments
4495 // on certain platforms that don't handle lots of active pthread_cond_timedwait()
4496 // timers in a graceful fashion.
4497 //
4498 // 4. When the abstime value is in the past it appears that control returns
4499 // correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
4500 // Subsequent timedwait/wait calls may hang indefinitely. Given that, we
4501 // can avoid the problem by reinitializing the condvar -- by cond_destroy()
4502 // followed by cond_init() -- after all calls to pthread_cond_timedwait().
4503 // It may be possible to avoid reinitialization by checking the return
4504 // value from pthread_cond_timedwait(). In addition to reinitializing the
4505 // condvar we must establish the invariant that cond_signal() is only called
4506 // within critical sections protected by the adjunct mutex. This prevents
4507 // cond_signal() from "seeing" a condvar that's in the midst of being
4508 // reinitialized or that is corrupt. Sadly, this invariant obviates the
4509 // desirable signal-after-unlock optimization that avoids futile context switching.
4510 //
4511 // I'm also concerned that some versions of NTPL might allocate an auxilliary
4512 // structure when a condvar is used or initialized. cond_destroy() would
4513 // release the helper structure. Our reinitialize-after-timedwait fix
4514 // put excessive stress on malloc/free and locks protecting the c-heap.
4515 //
4516 // We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
4517 // It may be possible to refine (4) by checking the kernel and NTPL verisons
4518 // and only enabling the work-around for vulnerable environments.
4519
4520 // utility to compute the abstime argument to timedwait:
4521 // millis is the relative timeout time
4522 // abstime will be the absolute timeout time
4523 // TODO: replace compute_abstime() with unpackTime()
4524
4525 static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
4526 if (millis < 0) millis = 0;
4527 struct timeval now;
4528 int status = gettimeofday(&now, NULL);
4529 assert(status == 0, "gettimeofday");
4530 jlong seconds = millis / 1000;
4531 millis %= 1000;
4532 if (seconds > 50000000) { // see man cond_timedwait(3T)
4533 seconds = 50000000;
4534 }
4535 abstime->tv_sec = now.tv_sec + seconds;
4536 long usec = now.tv_usec + millis * 1000;
4537 if (usec >= 1000000) {
4538 abstime->tv_sec += 1;
4539 usec -= 1000000;
4540 }
4541 abstime->tv_nsec = usec * 1000;
4542 return abstime;
4543 }
4544
4545
4546 // Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
4547 // Conceptually TryPark() should be equivalent to park(0).
4548
4549 int os::PlatformEvent::TryPark() {
4550 for (;;) {
4551 const int v = _Event ;
4552 guarantee ((v == 0) || (v == 1), "invariant") ;
4553 if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
4554 }
4555 }
4556
4557 void os::PlatformEvent::park() { // AKA "down()"
4558 // Invariant: Only the thread associated with the Event/PlatformEvent
4559 // may call park().
4560 // TODO: assert that _Assoc != NULL or _Assoc == Self
4561 int v ;
4562 for (;;) {
4563 v = _Event ;
4564 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
4565 }
4566 guarantee (v >= 0, "invariant") ;
4567 if (v == 0) {
4568 // Do this the hard way by blocking ...
4569 int status = pthread_mutex_lock(_mutex);
4570 assert_status(status == 0, status, "mutex_lock");
4571 guarantee (_nParked == 0, "invariant") ;
4572 ++ _nParked ;
4573 while (_Event < 0) {
4574 status = pthread_cond_wait(_cond, _mutex);
4575 // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
4576 // Treat this the same as if the wait was interrupted
4577 if (status == ETIME) { status = EINTR; }
4578 assert_status(status == 0 || status == EINTR, status, "cond_wait");
4579 }
4580 -- _nParked ;
4581
4582 // In theory we could move the ST of 0 into _Event past the unlock(),
4583 // but then we'd need a MEMBAR after the ST.
4584 _Event = 0 ;
4585 status = pthread_mutex_unlock(_mutex);
4586 assert_status(status == 0, status, "mutex_unlock");
4587 }
4588 guarantee (_Event >= 0, "invariant") ;
4589 }
4590
4591 int os::PlatformEvent::park(jlong millis) {
4592 guarantee (_nParked == 0, "invariant") ;
4593
4594 int v ;
4595 for (;;) {
4596 v = _Event ;
4597 if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
4598 }
4599 guarantee (v >= 0, "invariant") ;
4600 if (v != 0) return OS_OK ;
4601
4602 // We do this the hard way, by blocking the thread.
4603 // Consider enforcing a minimum timeout value.
4604 struct timespec abst;
4605 compute_abstime(&abst, millis);
4606
4607 int ret = OS_TIMEOUT;
4608 int status = pthread_mutex_lock(_mutex);
4609 assert_status(status == 0, status, "mutex_lock");
4610 guarantee (_nParked == 0, "invariant") ;
4611 ++_nParked ;
4612
4613 // Object.wait(timo) will return because of
4614 // (a) notification
4615 // (b) timeout
4616 // (c) thread.interrupt
4617 //
4618 // Thread.interrupt and object.notify{All} both call Event::set.
4619 // That is, we treat thread.interrupt as a special case of notification.
4620 // The underlying Solaris implementation, cond_timedwait, admits
4621 // spurious/premature wakeups, but the JLS/JVM spec prevents the
4622 // JVM from making those visible to Java code. As such, we must
4623 // filter out spurious wakeups. We assume all ETIME returns are valid.
4624 //
4625 // TODO: properly differentiate simultaneous notify+interrupt.
4626 // In that case, we should propagate the notify to another waiter.
4627
4628 while (_Event < 0) {
4629 status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
4630 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
4631 pthread_cond_destroy (_cond);
4632 pthread_cond_init (_cond, NULL) ;
4633 }
4634 assert_status(status == 0 || status == EINTR ||
4635 status == ETIME || status == ETIMEDOUT,
4636 status, "cond_timedwait");
4637 if (!FilterSpuriousWakeups) break ; // previous semantics
4638 if (status == ETIME || status == ETIMEDOUT) break ;
4639 // We consume and ignore EINTR and spurious wakeups.
4640 }
4641 --_nParked ;
4642 if (_Event >= 0) {
4643 ret = OS_OK;
4644 }
4645 _Event = 0 ;
4646 status = pthread_mutex_unlock(_mutex);
4647 assert_status(status == 0, status, "mutex_unlock");
4648 assert (_nParked == 0, "invariant") ;
4649 return ret;
4650 }
4651
4652 void os::PlatformEvent::unpark() {
4653 int v, AnyWaiters ;
4654 for (;;) {
4655 v = _Event ;
4656 if (v > 0) {
4657 // The LD of _Event could have reordered or be satisfied
4658 // by a read-aside from this processor's write buffer.
4659 // To avoid problems execute a barrier and then
4660 // ratify the value.
4661 OrderAccess::fence() ;
4662 if (_Event == v) return ;
4663 continue ;
4664 }
4665 if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ;
4666 }
4667 if (v < 0) {
4668 // Wait for the thread associated with the event to vacate
4669 int status = pthread_mutex_lock(_mutex);
4670 assert_status(status == 0, status, "mutex_lock");
4671 AnyWaiters = _nParked ;
4672 assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ;
4673 if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
4674 AnyWaiters = 0 ;
4675 pthread_cond_signal (_cond);
4676 }
4677 status = pthread_mutex_unlock(_mutex);
4678 assert_status(status == 0, status, "mutex_unlock");
4679 if (AnyWaiters != 0) {
4680 status = pthread_cond_signal(_cond);
4681 assert_status(status == 0, status, "cond_signal");
4682 }
4683 }
4684
4685 // Note that we signal() _after dropping the lock for "immortal" Events.
4686 // This is safe and avoids a common class of futile wakeups. In rare
4687 // circumstances this can cause a thread to return prematurely from
4688 // cond_{timed}wait() but the spurious wakeup is benign and the victim will
4689 // simply re-test the condition and re-park itself.
4690 }
4691
4692
4693 // JSR166
4694 // -------------------------------------------------------
4695
4696 /*
4697 * The solaris and linux implementations of park/unpark are fairly
4698 * conservative for now, but can be improved. They currently use a
4699 * mutex/condvar pair, plus a a count.
4700 * Park decrements count if > 0, else does a condvar wait. Unpark
4701 * sets count to 1 and signals condvar. Only one thread ever waits
4702 * on the condvar. Contention seen when trying to park implies that someone
4703 * is unparking you, so don't wait. And spurious returns are fine, so there
4704 * is no need to track notifications.
4705 */
4706
4707
4708 #define NANOSECS_PER_SEC 1000000000
4709 #define NANOSECS_PER_MILLISEC 1000000
4710 #define MAX_SECS 100000000
4711 /*
4712 * This code is common to linux and solaris and will be moved to a
4713 * common place in dolphin.
4714 *
4715 * The passed in time value is either a relative time in nanoseconds
4716 * or an absolute time in milliseconds. Either way it has to be unpacked
4717 * into suitable seconds and nanoseconds components and stored in the
4718 * given timespec structure.
4719 * Given time is a 64-bit value and the time_t used in the timespec is only
4720 * a signed-32-bit value (except on 64-bit Linux) we have to watch for
4721 * overflow if times way in the future are given. Further on Solaris versions
4722 * prior to 10 there is a restriction (see cond_timedwait) that the specified
4723 * number of seconds, in abstime, is less than current_time + 100,000,000.
4724 * As it will be 28 years before "now + 100000000" will overflow we can
4725 * ignore overflow and just impose a hard-limit on seconds using the value
4726 * of "now + 100,000,000". This places a limit on the timeout of about 3.17
4727 * years from "now".
4728 */
4729
4730 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
4731 assert (time > 0, "convertTime");
4732
4733 struct timeval now;
4734 int status = gettimeofday(&now, NULL);
4735 assert(status == 0, "gettimeofday");
4736
4737 time_t max_secs = now.tv_sec + MAX_SECS;
4738
4739 if (isAbsolute) {
4740 jlong secs = time / 1000;
4741 if (secs > max_secs) {
4742 absTime->tv_sec = max_secs;
4743 }
4744 else {
4745 absTime->tv_sec = secs;
4746 }
4747 absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
4748 }
4749 else {
4750 jlong secs = time / NANOSECS_PER_SEC;
4751 if (secs >= MAX_SECS) {
4752 absTime->tv_sec = max_secs;
4753 absTime->tv_nsec = 0;
4754 }
4755 else {
4756 absTime->tv_sec = now.tv_sec + secs;
4757 absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
4758 if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
4759 absTime->tv_nsec -= NANOSECS_PER_SEC;
4760 ++absTime->tv_sec; // note: this must be <= max_secs
4761 }
4762 }
4763 }
4764 assert(absTime->tv_sec >= 0, "tv_sec < 0");
4765 assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
4766 assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
4767 assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
4768 }
4769
4770 void Parker::park(bool isAbsolute, jlong time) {
4771 // Optional fast-path check:
4772 // Return immediately if a permit is available.
4773 if (_counter > 0) {
4774 _counter = 0 ;
4775 OrderAccess::fence();
4776 return ;
4777 }
4778
4779 Thread* thread = Thread::current();
4780 assert(thread->is_Java_thread(), "Must be JavaThread");
4781 JavaThread *jt = (JavaThread *)thread;
4782
4783 // Optional optimization -- avoid state transitions if there's an interrupt pending.
4784 // Check interrupt before trying to wait
4785 if (Thread::is_interrupted(thread, false)) {
4786 return;
4787 }
4788
4789 // Next, demultiplex/decode time arguments
4790 timespec absTime;
4791 if (time < 0) { // don't wait at all
4792 return;
4793 }
4794 if (time > 0) {
4795 unpackTime(&absTime, isAbsolute, time);
4796 }
4797
4798
4799 // Enter safepoint region
4800 // Beware of deadlocks such as 6317397.
4801 // The per-thread Parker:: mutex is a classic leaf-lock.
4802 // In particular a thread must never block on the Threads_lock while
4803 // holding the Parker:: mutex. If safepoints are pending both the
4804 // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
4805 ThreadBlockInVM tbivm(jt);
4806
4807 // Don't wait if cannot get lock since interference arises from
4808 // unblocking. Also. check interrupt before trying wait
4809 if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
4810 return;
4811 }
4812
4813 int status ;
4814 if (_counter > 0) { // no wait needed
4815 _counter = 0;
4816 status = pthread_mutex_unlock(_mutex);
4817 assert (status == 0, "invariant") ;
4818 OrderAccess::fence();
4819 return;
4820 }
4821
4822 #ifdef ASSERT
4823 // Don't catch signals while blocked; let the running threads have the signals.
4824 // (This allows a debugger to break into the running thread.)
4825 sigset_t oldsigs;
4826 sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
4827 pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
4828 #endif
4829
4830 OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
4831 jt->set_suspend_equivalent();
4832 // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
4833
4834 if (time == 0) {
4835 status = pthread_cond_wait (_cond, _mutex) ;
4836 } else {
4837 status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ;
4838 if (status != 0 && WorkAroundNPTLTimedWaitHang) {
4839 pthread_cond_destroy (_cond) ;
4840 pthread_cond_init (_cond, NULL);
4841 }
4842 }
4843 assert_status(status == 0 || status == EINTR ||
4844 status == ETIME || status == ETIMEDOUT,
4845 status, "cond_timedwait");
4846
4847 #ifdef ASSERT
4848 pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
4849 #endif
4850
4851 _counter = 0 ;
4852 status = pthread_mutex_unlock(_mutex) ;
4853 assert_status(status == 0, status, "invariant") ;
4854 // If externally suspended while waiting, re-suspend
4855 if (jt->handle_special_suspend_equivalent_condition()) {
4856 jt->java_suspend_self();
4857 }
4858
4859 OrderAccess::fence();
4860 }
4861
4862 void Parker::unpark() {
4863 int s, status ;
4864 status = pthread_mutex_lock(_mutex);
4865 assert (status == 0, "invariant") ;
4866 s = _counter;
4867 _counter = 1;
4868 if (s < 1) {
4869 if (WorkAroundNPTLTimedWaitHang) {
4870 status = pthread_cond_signal (_cond) ;
4871 assert (status == 0, "invariant") ;
4872 status = pthread_mutex_unlock(_mutex);
4873 assert (status == 0, "invariant") ;
4874 } else {
4875 status = pthread_mutex_unlock(_mutex);
4876 assert (status == 0, "invariant") ;
4877 status = pthread_cond_signal (_cond) ;
4878 assert (status == 0, "invariant") ;
4879 }
4880 } else {
4881 pthread_mutex_unlock(_mutex);
4882 assert (status == 0, "invariant") ;
4883 }
4884 }
4885
4886
4887 extern char** environ;
4888
4889 #ifndef __NR_fork
4890 #define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
4891 #endif
4892
4893 #ifndef __NR_execve
4894 #define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
4895 #endif
4896
4897 // Run the specified command in a separate process. Return its exit value,
4898 // or -1 on failure (e.g. can't fork a new process).
4899 // Unlike system(), this function can be called from signal handler. It
4900 // doesn't block SIGINT et al.
4901 int os::fork_and_exec(char* cmd) {
4902 const char * argv[4] = {"sh", "-c", cmd, NULL};
4903
4904 // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
4905 // pthread_atfork handlers and reset pthread library. All we need is a
4906 // separate process to execve. Make a direct syscall to fork process.
4907 // On IA64 there's no fork syscall, we have to use fork() and hope for
4908 // the best...
4909 pid_t pid = NOT_IA64(syscall(__NR_fork);)
4910 IA64_ONLY(fork();)
4911
4912 if (pid < 0) {
4913 // fork failed
4914 return -1;
4915
4916 } else if (pid == 0) {
4917 // child process
4918
4919 // execve() in LinuxThreads will call pthread_kill_other_threads_np()
4920 // first to kill every thread on the thread list. Because this list is
4921 // not reset by fork() (see notes above), execve() will instead kill
4922 // every thread in the parent process. We know this is the only thread
4923 // in the new process, so make a system call directly.
4924 // IA64 should use normal execve() from glibc to match the glibc fork()
4925 // above.
4926 NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
4927 IA64_ONLY(execve("/bin/sh", (char* const*)argv, environ);)
4928
4929 // execve failed
4930 _exit(-1);
4931
4932 } else {
4933 // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
4934 // care about the actual exit code, for now.
4935
4936 int status;
4937
4938 // Wait for the child process to exit. This returns immediately if
4939 // the child has already exited. */
4940 while (waitpid(pid, &status, 0) < 0) {
4941 switch (errno) {
4942 case ECHILD: return 0;
4943 case EINTR: break;
4944 default: return -1;
4945 }
4946 }
4947
4948 if (WIFEXITED(status)) {
4949 // The child exited normally; get its exit code.
4950 return WEXITSTATUS(status);
4951 } else if (WIFSIGNALED(status)) {
4952 // The child exited because of a signal
4953 // The best value to return is 0x80 + signal number,
4954 // because that is what all Unix shells do, and because
4955 // it allows callers to distinguish between process exit and
4956 // process death by signal.
4957 return 0x80 + WTERMSIG(status);
4958 } else {
4959 // Unknown exit code; pass it through
4960 return status;
4961 }
4962 }
4963 }