--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/os/linux/vm/os_linux.cpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,4594 @@
+/*
+ * Copyright 1999-2007 Sun Microsystems, Inc. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+// do not include precompiled header file
+# include "incls/_os_linux.cpp.incl"
+
+// put OS-includes here
+# include <sys/types.h>
+# include <sys/mman.h>
+# include <pthread.h>
+# include <signal.h>
+# include <errno.h>
+# include <dlfcn.h>
+# include <stdio.h>
+# include <unistd.h>
+# include <sys/resource.h>
+# include <pthread.h>
+# include <sys/stat.h>
+# include <sys/time.h>
+# include <sys/times.h>
+# include <sys/utsname.h>
+# include <sys/socket.h>
+# include <sys/wait.h>
+# include <pwd.h>
+# include <poll.h>
+# include <semaphore.h>
+# include <fcntl.h>
+# include <string.h>
+# include <syscall.h>
+# include <sys/sysinfo.h>
+# include <gnu/libc-version.h>
+# include <sys/ipc.h>
+# include <sys/shm.h>
+# include <link.h>
+
+#define MAX_PATH (2 * K)
+
+// for timer info max values which include all bits
+#define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
+#define SEC_IN_NANOSECS 1000000000LL
+
+////////////////////////////////////////////////////////////////////////////////
+// global variables
+julong os::Linux::_physical_memory = 0;
+
+address os::Linux::_initial_thread_stack_bottom = NULL;
+uintptr_t os::Linux::_initial_thread_stack_size = 0;
+
+int (*os::Linux::_clock_gettime)(clockid_t, struct timespec *) = NULL;
+int (*os::Linux::_pthread_getcpuclockid)(pthread_t, clockid_t *) = NULL;
+Mutex* os::Linux::_createThread_lock = NULL;
+pthread_t os::Linux::_main_thread;
+int os::Linux::_page_size = -1;
+bool os::Linux::_is_floating_stack = false;
+bool os::Linux::_is_NPTL = false;
+bool os::Linux::_supports_fast_thread_cpu_time = false;
+char * os::Linux::_glibc_version = NULL;
+char * os::Linux::_libpthread_version = NULL;
+
+static jlong initial_time_count=0;
+
+static int clock_tics_per_sec = 100;
+
+// For diagnostics to print a message once. see run_periodic_checks
+static sigset_t check_signal_done;
+static bool check_signals = true;;
+
+static pid_t _initial_pid = 0;
+
+/* Signal number used to suspend/resume a thread */
+
+/* do not use any signal number less than SIGSEGV, see 4355769 */
+static int SR_signum = SIGUSR2;
+sigset_t SR_sigset;
+
+////////////////////////////////////////////////////////////////////////////////
+// utility functions
+
+static int SR_initialize();
+static int SR_finalize();
+
+julong os::available_memory() {
+ return Linux::available_memory();
+}
+
+julong os::Linux::available_memory() {
+ // values in struct sysinfo are "unsigned long"
+ struct sysinfo si;
+ sysinfo(&si);
+
+ return (julong)si.freeram * si.mem_unit;
+}
+
+julong os::physical_memory() {
+ return Linux::physical_memory();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// environment support
+
+bool os::getenv(const char* name, char* buf, int len) {
+ const char* val = ::getenv(name);
+ if (val != NULL && strlen(val) < (size_t)len) {
+ strcpy(buf, val);
+ return true;
+ }
+ if (len > 0) buf[0] = 0; // return a null string
+ return false;
+}
+
+
+// Return true if user is running as root.
+
+bool os::have_special_privileges() {
+ static bool init = false;
+ static bool privileges = false;
+ if (!init) {
+ privileges = (getuid() != geteuid()) || (getgid() != getegid());
+ init = true;
+ }
+ return privileges;
+}
+
+
+#ifndef SYS_gettid
+// i386: 224, ia64: 1105, amd64: 186, sparc 143
+#ifdef __ia64__
+#define SYS_gettid 1105
+#elif __i386__
+#define SYS_gettid 224
+#elif __amd64__
+#define SYS_gettid 186
+#elif __sparc__
+#define SYS_gettid 143
+#else
+#error define gettid for the arch
+#endif
+#endif
+
+// Cpu architecture string
+#if defined(IA64)
+static char cpu_arch[] = "ia64";
+#elif defined(IA32)
+static char cpu_arch[] = "i386";
+#elif defined(AMD64)
+static char cpu_arch[] = "amd64";
+#elif defined(SPARC)
+# ifdef _LP64
+static char cpu_arch[] = "sparcv9";
+# else
+static char cpu_arch[] = "sparc";
+# endif
+#else
+#error Add appropriate cpu_arch setting
+#endif
+
+
+// pid_t gettid()
+//
+// Returns the kernel thread id of the currently running thread. Kernel
+// thread id is used to access /proc.
+//
+// (Note that getpid() on LinuxThreads returns kernel thread id too; but
+// on NPTL, it returns the same pid for all threads, as required by POSIX.)
+//
+pid_t os::Linux::gettid() {
+ int rslt = syscall(SYS_gettid);
+ if (rslt == -1) {
+ // old kernel, no NPTL support
+ return getpid();
+ } else {
+ return (pid_t)rslt;
+ }
+}
+
+// Most versions of linux have a bug where the number of processors are
+// determined by looking at the /proc file system. In a chroot environment,
+// the system call returns 1. This causes the VM to act as if it is
+// a single processor and elide locking (see is_MP() call).
+static bool unsafe_chroot_detected = false;
+static char *unstable_chroot_error = "/proc file system not found.\n"
+ "Java may be unstable running multithreaded in a chroot "
+ "environment on Linux when /proc filesystem is not mounted.";
+
+void os::Linux::initialize_system_info() {
+ _processor_count = sysconf(_SC_NPROCESSORS_CONF);
+ if (_processor_count == 1) {
+ pid_t pid = os::Linux::gettid();
+ char fname[32];
+ jio_snprintf(fname, sizeof(fname), "/proc/%d", pid);
+ FILE *fp = fopen(fname, "r");
+ if (fp == NULL) {
+ unsafe_chroot_detected = true;
+ } else {
+ fclose(fp);
+ }
+ }
+ _physical_memory = (julong)sysconf(_SC_PHYS_PAGES) * (julong)sysconf(_SC_PAGESIZE);
+ assert(_processor_count > 0, "linux error");
+}
+
+void os::init_system_properties_values() {
+// char arch[12];
+// sysinfo(SI_ARCHITECTURE, arch, sizeof(arch));
+
+ // The next steps are taken in the product version:
+ //
+ // Obtain the JAVA_HOME value from the location of libjvm[_g].so.
+ // This library should be located at:
+ // <JAVA_HOME>/jre/lib/<arch>/{client|server}/libjvm[_g].so.
+ //
+ // If "/jre/lib/" appears at the right place in the path, then we
+ // assume libjvm[_g].so is installed in a JDK and we use this path.
+ //
+ // Otherwise exit with message: "Could not create the Java virtual machine."
+ //
+ // The following extra steps are taken in the debugging version:
+ //
+ // If "/jre/lib/" does NOT appear at the right place in the path
+ // instead of exit check for $JAVA_HOME environment variable.
+ //
+ // If it is defined and we are able to locate $JAVA_HOME/jre/lib/<arch>,
+ // then we append a fake suffix "hotspot/libjvm[_g].so" to this path so
+ // it looks like libjvm[_g].so is installed there
+ // <JAVA_HOME>/jre/lib/<arch>/hotspot/libjvm[_g].so.
+ //
+ // Otherwise exit.
+ //
+ // Important note: if the location of libjvm.so changes this
+ // code needs to be changed accordingly.
+
+ // The next few definitions allow the code to be verbatim:
+#define malloc(n) (char*)NEW_C_HEAP_ARRAY(char, (n))
+#define getenv(n) ::getenv(n)
+
+/*
+ * See ld(1):
+ * The linker uses the following search paths to locate required
+ * shared libraries:
+ * 1: ...
+ * ...
+ * 7: The default directories, normally /lib and /usr/lib.
+ */
+#define DEFAULT_LIBPATH "/lib:/usr/lib"
+
+#define EXTENSIONS_DIR "/lib/ext"
+#define ENDORSED_DIR "/lib/endorsed"
+#define REG_DIR "/usr/java/packages"
+
+ {
+ /* sysclasspath, java_home, dll_dir */
+ {
+ char *home_path;
+ char *dll_path;
+ char *pslash;
+ char buf[MAXPATHLEN];
+ os::jvm_path(buf, sizeof(buf));
+
+ // Found the full path to libjvm.so.
+ // Now cut the path to <java_home>/jre if we can.
+ *(strrchr(buf, '/')) = '\0'; /* get rid of /libjvm.so */
+ pslash = strrchr(buf, '/');
+ if (pslash != NULL)
+ *pslash = '\0'; /* get rid of /{client|server|hotspot} */
+ dll_path = malloc(strlen(buf) + 1);
+ if (dll_path == NULL)
+ return;
+ strcpy(dll_path, buf);
+ Arguments::set_dll_dir(dll_path);
+
+ if (pslash != NULL) {
+ pslash = strrchr(buf, '/');
+ if (pslash != NULL) {
+ *pslash = '\0'; /* get rid of /<arch> */
+ pslash = strrchr(buf, '/');
+ if (pslash != NULL)
+ *pslash = '\0'; /* get rid of /lib */
+ }
+ }
+
+ home_path = malloc(strlen(buf) + 1);
+ if (home_path == NULL)
+ return;
+ strcpy(home_path, buf);
+ Arguments::set_java_home(home_path);
+
+ if (!set_boot_path('/', ':'))
+ return;
+ }
+
+ /*
+ * Where to look for native libraries
+ *
+ * Note: Due to a legacy implementation, most of the library path
+ * is set in the launcher. This was to accomodate linking restrictions
+ * on legacy Linux implementations (which are no longer supported).
+ * Eventually, all the library path setting will be done here.
+ *
+ * However, to prevent the proliferation of improperly built native
+ * libraries, the new path component /usr/java/packages is added here.
+ * Eventually, all the library path setting will be done here.
+ */
+ {
+ char *ld_library_path;
+
+ /*
+ * Construct the invariant part of ld_library_path. Note that the
+ * space for the colon and the trailing null are provided by the
+ * nulls included by the sizeof operator (so actually we allocate
+ * a byte more than necessary).
+ */
+ ld_library_path = (char *) malloc(sizeof(REG_DIR) + sizeof("/lib/") +
+ strlen(cpu_arch) + sizeof(DEFAULT_LIBPATH));
+ sprintf(ld_library_path, REG_DIR "/lib/%s:" DEFAULT_LIBPATH, cpu_arch);
+
+ /*
+ * Get the user setting of LD_LIBRARY_PATH, and prepended it. It
+ * should always exist (until the legacy problem cited above is
+ * addressed).
+ */
+ char *v = getenv("LD_LIBRARY_PATH");
+ if (v != NULL) {
+ char *t = ld_library_path;
+ /* That's +1 for the colon and +1 for the trailing '\0' */
+ ld_library_path = (char *) malloc(strlen(v) + 1 + strlen(t) + 1);
+ sprintf(ld_library_path, "%s:%s", v, t);
+ }
+ Arguments::set_library_path(ld_library_path);
+ }
+
+ /*
+ * Extensions directories.
+ *
+ * Note that the space for the colon and the trailing null are provided
+ * by the nulls included by the sizeof operator (so actually one byte more
+ * than necessary is allocated).
+ */
+ {
+ char *buf = malloc(strlen(Arguments::get_java_home()) +
+ sizeof(EXTENSIONS_DIR) + sizeof(REG_DIR) + sizeof(EXTENSIONS_DIR));
+ sprintf(buf, "%s" EXTENSIONS_DIR ":" REG_DIR EXTENSIONS_DIR,
+ Arguments::get_java_home());
+ Arguments::set_ext_dirs(buf);
+ }
+
+ /* Endorsed standards default directory. */
+ {
+ char * buf;
+ buf = malloc(strlen(Arguments::get_java_home()) + sizeof(ENDORSED_DIR));
+ sprintf(buf, "%s" ENDORSED_DIR, Arguments::get_java_home());
+ Arguments::set_endorsed_dirs(buf);
+ }
+ }
+
+#undef malloc
+#undef getenv
+#undef EXTENSIONS_DIR
+#undef ENDORSED_DIR
+
+ // Done
+ return;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// breakpoint support
+
+void os::breakpoint() {
+ BREAKPOINT;
+}
+
+extern "C" void breakpoint() {
+ // use debugger to set breakpoint here
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// signal support
+
+debug_only(static bool signal_sets_initialized = false);
+static sigset_t unblocked_sigs, vm_sigs, allowdebug_blocked_sigs;
+
+bool os::Linux::is_sig_ignored(int sig) {
+ struct sigaction oact;
+ sigaction(sig, (struct sigaction*)NULL, &oact);
+ void* ohlr = oact.sa_sigaction ? CAST_FROM_FN_PTR(void*, oact.sa_sigaction)
+ : CAST_FROM_FN_PTR(void*, oact.sa_handler);
+ if (ohlr == CAST_FROM_FN_PTR(void*, SIG_IGN))
+ return true;
+ else
+ return false;
+}
+
+void os::Linux::signal_sets_init() {
+ // Should also have an assertion stating we are still single-threaded.
+ assert(!signal_sets_initialized, "Already initialized");
+ // Fill in signals that are necessarily unblocked for all threads in
+ // the VM. Currently, we unblock the following signals:
+ // SHUTDOWN{1,2,3}_SIGNAL: for shutdown hooks support (unless over-ridden
+ // by -Xrs (=ReduceSignalUsage));
+ // BREAK_SIGNAL which is unblocked only by the VM thread and blocked by all
+ // other threads. The "ReduceSignalUsage" boolean tells us not to alter
+ // the dispositions or masks wrt these signals.
+ // Programs embedding the VM that want to use the above signals for their
+ // own purposes must, at this time, use the "-Xrs" option to prevent
+ // interference with shutdown hooks and BREAK_SIGNAL thread dumping.
+ // (See bug 4345157, and other related bugs).
+ // In reality, though, unblocking these signals is really a nop, since
+ // these signals are not blocked by default.
+ sigemptyset(&unblocked_sigs);
+ sigemptyset(&allowdebug_blocked_sigs);
+ sigaddset(&unblocked_sigs, SIGILL);
+ sigaddset(&unblocked_sigs, SIGSEGV);
+ sigaddset(&unblocked_sigs, SIGBUS);
+ sigaddset(&unblocked_sigs, SIGFPE);
+ sigaddset(&unblocked_sigs, SR_signum);
+
+ if (!ReduceSignalUsage) {
+ if (!os::Linux::is_sig_ignored(SHUTDOWN1_SIGNAL)) {
+ sigaddset(&unblocked_sigs, SHUTDOWN1_SIGNAL);
+ sigaddset(&allowdebug_blocked_sigs, SHUTDOWN1_SIGNAL);
+ }
+ if (!os::Linux::is_sig_ignored(SHUTDOWN2_SIGNAL)) {
+ sigaddset(&unblocked_sigs, SHUTDOWN2_SIGNAL);
+ sigaddset(&allowdebug_blocked_sigs, SHUTDOWN2_SIGNAL);
+ }
+ if (!os::Linux::is_sig_ignored(SHUTDOWN3_SIGNAL)) {
+ sigaddset(&unblocked_sigs, SHUTDOWN3_SIGNAL);
+ sigaddset(&allowdebug_blocked_sigs, SHUTDOWN3_SIGNAL);
+ }
+ }
+ // Fill in signals that are blocked by all but the VM thread.
+ sigemptyset(&vm_sigs);
+ if (!ReduceSignalUsage)
+ sigaddset(&vm_sigs, BREAK_SIGNAL);
+ debug_only(signal_sets_initialized = true);
+
+}
+
+// These are signals that are unblocked while a thread is running Java.
+// (For some reason, they get blocked by default.)
+sigset_t* os::Linux::unblocked_signals() {
+ assert(signal_sets_initialized, "Not initialized");
+ return &unblocked_sigs;
+}
+
+// These are the signals that are blocked while a (non-VM) thread is
+// running Java. Only the VM thread handles these signals.
+sigset_t* os::Linux::vm_signals() {
+ assert(signal_sets_initialized, "Not initialized");
+ return &vm_sigs;
+}
+
+// These are signals that are blocked during cond_wait to allow debugger in
+sigset_t* os::Linux::allowdebug_blocked_signals() {
+ assert(signal_sets_initialized, "Not initialized");
+ return &allowdebug_blocked_sigs;
+}
+
+void os::Linux::hotspot_sigmask(Thread* thread) {
+
+ //Save caller's signal mask before setting VM signal mask
+ sigset_t caller_sigmask;
+ pthread_sigmask(SIG_BLOCK, NULL, &caller_sigmask);
+
+ OSThread* osthread = thread->osthread();
+ osthread->set_caller_sigmask(caller_sigmask);
+
+ pthread_sigmask(SIG_UNBLOCK, os::Linux::unblocked_signals(), NULL);
+
+ if (!ReduceSignalUsage) {
+ if (thread->is_VM_thread()) {
+ // Only the VM thread handles BREAK_SIGNAL ...
+ pthread_sigmask(SIG_UNBLOCK, vm_signals(), NULL);
+ } else {
+ // ... all other threads block BREAK_SIGNAL
+ pthread_sigmask(SIG_BLOCK, vm_signals(), NULL);
+ }
+ }
+}
+
+//////////////////////////////////////////////////////////////////////////////
+// detecting pthread library
+
+void os::Linux::libpthread_init() {
+ // Save glibc and pthread version strings. Note that _CS_GNU_LIBC_VERSION
+ // and _CS_GNU_LIBPTHREAD_VERSION are supported in glibc >= 2.3.2. Use a
+ // generic name for earlier versions.
+ // Define macros here so we can build HotSpot on old systems.
+# ifndef _CS_GNU_LIBC_VERSION
+# define _CS_GNU_LIBC_VERSION 2
+# endif
+# ifndef _CS_GNU_LIBPTHREAD_VERSION
+# define _CS_GNU_LIBPTHREAD_VERSION 3
+# endif
+
+ size_t n = confstr(_CS_GNU_LIBC_VERSION, NULL, 0);
+ if (n > 0) {
+ char *str = (char *)malloc(n);
+ confstr(_CS_GNU_LIBC_VERSION, str, n);
+ os::Linux::set_glibc_version(str);
+ } else {
+ // _CS_GNU_LIBC_VERSION is not supported, try gnu_get_libc_version()
+ static char _gnu_libc_version[32];
+ jio_snprintf(_gnu_libc_version, sizeof(_gnu_libc_version),
+ "glibc %s %s", gnu_get_libc_version(), gnu_get_libc_release());
+ os::Linux::set_glibc_version(_gnu_libc_version);
+ }
+
+ n = confstr(_CS_GNU_LIBPTHREAD_VERSION, NULL, 0);
+ if (n > 0) {
+ char *str = (char *)malloc(n);
+ confstr(_CS_GNU_LIBPTHREAD_VERSION, str, n);
+
+ // Vanilla RH-9 (glibc 2.3.2) has a bug that confstr() always tells
+ // us "NPTL-0.29" even we are running with LinuxThreads. Check if this
+ // is the case:
+ if (strcmp(os::Linux::glibc_version(), "glibc 2.3.2") == 0 &&
+ strstr(str, "NPTL")) {
+ // LinuxThreads has a hard limit on max number of threads. So
+ // sysconf(_SC_THREAD_THREADS_MAX) will return a positive value.
+ // On the other hand, NPTL does not have such a limit, sysconf()
+ // will return -1 and errno is not changed. Check if it is really
+ // NPTL:
+ if (sysconf(_SC_THREAD_THREADS_MAX) > 0) {
+ free(str);
+ str = "linuxthreads";
+ }
+ }
+ os::Linux::set_libpthread_version(str);
+ } else {
+ // glibc before 2.3.2 only has LinuxThreads.
+ os::Linux::set_libpthread_version("linuxthreads");
+ }
+
+ if (strstr(libpthread_version(), "NPTL")) {
+ os::Linux::set_is_NPTL();
+ } else {
+ os::Linux::set_is_LinuxThreads();
+ }
+
+ // LinuxThreads have two flavors: floating-stack mode, which allows variable
+ // stack size; and fixed-stack mode. NPTL is always floating-stack.
+ if (os::Linux::is_NPTL() || os::Linux::supports_variable_stack_size()) {
+ os::Linux::set_is_floating_stack();
+ }
+}
+
+/////////////////////////////////////////////////////////////////////////////
+// thread stack
+
+// Force Linux kernel to expand current thread stack. If "bottom" is close
+// to the stack guard, caller should block all signals.
+//
+// MAP_GROWSDOWN:
+// A special mmap() flag that is used to implement thread stacks. It tells
+// kernel that the memory region should extend downwards when needed. This
+// allows early versions of LinuxThreads to only mmap the first few pages
+// when creating a new thread. Linux kernel will automatically expand thread
+// stack as needed (on page faults).
+//
+// However, because the memory region of a MAP_GROWSDOWN stack can grow on
+// demand, if a page fault happens outside an already mapped MAP_GROWSDOWN
+// region, it's hard to tell if the fault is due to a legitimate stack
+// access or because of reading/writing non-exist memory (e.g. buffer
+// overrun). As a rule, if the fault happens below current stack pointer,
+// Linux kernel does not expand stack, instead a SIGSEGV is sent to the
+// application (see Linux kernel fault.c).
+//
+// This Linux feature can cause SIGSEGV when VM bangs thread stack for
+// stack overflow detection.
+//
+// Newer version of LinuxThreads (since glibc-2.2, or, RH-7.x) and NPTL do
+// not use this flag. However, the stack of initial thread is not created
+// by pthread, it is still MAP_GROWSDOWN. Also it's possible (though
+// unlikely) that user code can create a thread with MAP_GROWSDOWN stack
+// and then attach the thread to JVM.
+//
+// To get around the problem and allow stack banging on Linux, we need to
+// manually expand thread stack after receiving the SIGSEGV.
+//
+// There are two ways to expand thread stack to address "bottom", we used
+// both of them in JVM before 1.5:
+// 1. adjust stack pointer first so that it is below "bottom", and then
+// touch "bottom"
+// 2. mmap() the page in question
+//
+// Now alternate signal stack is gone, it's harder to use 2. For instance,
+// if current sp is already near the lower end of page 101, and we need to
+// call mmap() to map page 100, it is possible that part of the mmap() frame
+// will be placed in page 100. When page 100 is mapped, it is zero-filled.
+// That will destroy the mmap() frame and cause VM to crash.
+//
+// The following code works by adjusting sp first, then accessing the "bottom"
+// page to force a page fault. Linux kernel will then automatically expand the
+// stack mapping.
+//
+// _expand_stack_to() assumes its frame size is less than page size, which
+// should always be true if the function is not inlined.
+
+#if __GNUC__ < 3 // gcc 2.x does not support noinline attribute
+#define NOINLINE
+#else
+#define NOINLINE __attribute__ ((noinline))
+#endif
+
+static void _expand_stack_to(address bottom) NOINLINE;
+
+static void _expand_stack_to(address bottom) {
+ address sp;
+ size_t size;
+ volatile char *p;
+
+ // Adjust bottom to point to the largest address within the same page, it
+ // gives us a one-page buffer if alloca() allocates slightly more memory.
+ bottom = (address)align_size_down((uintptr_t)bottom, os::Linux::page_size());
+ bottom += os::Linux::page_size() - 1;
+
+ // sp might be slightly above current stack pointer; if that's the case, we
+ // will alloca() a little more space than necessary, which is OK. Don't use
+ // os::current_stack_pointer(), as its result can be slightly below current
+ // stack pointer, causing us to not alloca enough to reach "bottom".
+ sp = (address)&sp;
+
+ if (sp > bottom) {
+ size = sp - bottom;
+ p = (volatile char *)alloca(size);
+ assert(p != NULL && p <= (volatile char *)bottom, "alloca problem?");
+ p[0] = '\0';
+ }
+}
+
+bool os::Linux::manually_expand_stack(JavaThread * t, address addr) {
+ assert(t!=NULL, "just checking");
+ assert(t->osthread()->expanding_stack(), "expand should be set");
+ assert(t->stack_base() != NULL, "stack_base was not initialized");
+
+ if (addr < t->stack_base() && addr >= t->stack_yellow_zone_base()) {
+ sigset_t mask_all, old_sigset;
+ sigfillset(&mask_all);
+ pthread_sigmask(SIG_SETMASK, &mask_all, &old_sigset);
+ _expand_stack_to(addr);
+ pthread_sigmask(SIG_SETMASK, &old_sigset, NULL);
+ return true;
+ }
+ return false;
+}
+
+//////////////////////////////////////////////////////////////////////////////
+// create new thread
+
+static address highest_vm_reserved_address();
+
+// check if it's safe to start a new thread
+static bool _thread_safety_check(Thread* thread) {
+ if (os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack()) {
+ // Fixed stack LinuxThreads (SuSE Linux/x86, and some versions of Redhat)
+ // Heap is mmap'ed at lower end of memory space. Thread stacks are
+ // allocated (MAP_FIXED) from high address space. Every thread stack
+ // occupies a fixed size slot (usually 2Mbytes, but user can change
+ // it to other values if they rebuild LinuxThreads).
+ //
+ // Problem with MAP_FIXED is that mmap() can still succeed even part of
+ // the memory region has already been mmap'ed. That means if we have too
+ // many threads and/or very large heap, eventually thread stack will
+ // collide with heap.
+ //
+ // Here we try to prevent heap/stack collision by comparing current
+ // stack bottom with the highest address that has been mmap'ed by JVM
+ // plus a safety margin for memory maps created by native code.
+ //
+ // This feature can be disabled by setting ThreadSafetyMargin to 0
+ //
+ if (ThreadSafetyMargin > 0) {
+ address stack_bottom = os::current_stack_base() - os::current_stack_size();
+
+ // not safe if our stack extends below the safety margin
+ return stack_bottom - ThreadSafetyMargin >= highest_vm_reserved_address();
+ } else {
+ return true;
+ }
+ } else {
+ // Floating stack LinuxThreads or NPTL:
+ // Unlike fixed stack LinuxThreads, thread stacks are not MAP_FIXED. When
+ // there's not enough space left, pthread_create() will fail. If we come
+ // here, that means enough space has been reserved for stack.
+ return true;
+ }
+}
+
+// Thread start routine for all newly created threads
+static void *java_start(Thread *thread) {
+ // Try to randomize the cache line index of hot stack frames.
+ // This helps when threads of the same stack traces evict each other's
+ // cache lines. The threads can be either from the same JVM instance, or
+ // from different JVM instances. The benefit is especially true for
+ // processors with hyperthreading technology.
+ static int counter = 0;
+ int pid = os::current_process_id();
+ alloca(((pid ^ counter++) & 7) * 128);
+
+ ThreadLocalStorage::set_thread(thread);
+
+ OSThread* osthread = thread->osthread();
+ Monitor* sync = osthread->startThread_lock();
+
+ // non floating stack LinuxThreads needs extra check, see above
+ if (!_thread_safety_check(thread)) {
+ // notify parent thread
+ MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
+ osthread->set_state(ZOMBIE);
+ sync->notify_all();
+ return NULL;
+ }
+
+ // thread_id is kernel thread id (similar to Solaris LWP id)
+ osthread->set_thread_id(os::Linux::gettid());
+
+ if (UseNUMA) {
+ int lgrp_id = os::numa_get_group_id();
+ if (lgrp_id != -1) {
+ thread->set_lgrp_id(lgrp_id);
+ }
+ }
+ // initialize signal mask for this thread
+ os::Linux::hotspot_sigmask(thread);
+
+ // initialize floating point control register
+ os::Linux::init_thread_fpu_state();
+
+ // handshaking with parent thread
+ {
+ MutexLockerEx ml(sync, Mutex::_no_safepoint_check_flag);
+
+ // notify parent thread
+ osthread->set_state(INITIALIZED);
+ sync->notify_all();
+
+ // wait until os::start_thread()
+ while (osthread->get_state() == INITIALIZED) {
+ sync->wait(Mutex::_no_safepoint_check_flag);
+ }
+ }
+
+ // call one more level start routine
+ thread->run();
+
+ return 0;
+}
+
+bool os::create_thread(Thread* thread, ThreadType thr_type, size_t stack_size) {
+ assert(thread->osthread() == NULL, "caller responsible");
+
+ // Allocate the OSThread object
+ OSThread* osthread = new OSThread(NULL, NULL);
+ if (osthread == NULL) {
+ return false;
+ }
+
+ // set the correct thread state
+ osthread->set_thread_type(thr_type);
+
+ // Initial state is ALLOCATED but not INITIALIZED
+ osthread->set_state(ALLOCATED);
+
+ thread->set_osthread(osthread);
+
+ // init thread attributes
+ pthread_attr_t attr;
+ pthread_attr_init(&attr);
+ pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+
+ // stack size
+ if (os::Linux::supports_variable_stack_size()) {
+ // calculate stack size if it's not specified by caller
+ if (stack_size == 0) {
+ stack_size = os::Linux::default_stack_size(thr_type);
+
+ switch (thr_type) {
+ case os::java_thread:
+ // Java threads use ThreadStackSize which default value can be changed with the flag -Xss
+ if (JavaThread::stack_size_at_create() > 0) stack_size = JavaThread::stack_size_at_create();
+ break;
+ case os::compiler_thread:
+ if (CompilerThreadStackSize > 0) {
+ stack_size = (size_t)(CompilerThreadStackSize * K);
+ break;
+ } // else fall through:
+ // use VMThreadStackSize if CompilerThreadStackSize is not defined
+ case os::vm_thread:
+ case os::pgc_thread:
+ case os::cgc_thread:
+ case os::watcher_thread:
+ if (VMThreadStackSize > 0) stack_size = (size_t)(VMThreadStackSize * K);
+ break;
+ }
+ }
+
+ stack_size = MAX2(stack_size, os::Linux::min_stack_allowed);
+ pthread_attr_setstacksize(&attr, stack_size);
+ } else {
+ // let pthread_create() pick the default value.
+ }
+
+ // glibc guard page
+ pthread_attr_setguardsize(&attr, os::Linux::default_guard_size(thr_type));
+
+ ThreadState state;
+
+ {
+ // Serialize thread creation if we are running with fixed stack LinuxThreads
+ bool lock = os::Linux::is_LinuxThreads() && !os::Linux::is_floating_stack();
+ if (lock) {
+ os::Linux::createThread_lock()->lock_without_safepoint_check();
+ }
+
+ pthread_t tid;
+ int ret = pthread_create(&tid, &attr, (void* (*)(void*)) java_start, thread);
+
+ pthread_attr_destroy(&attr);
+
+ if (ret != 0) {
+ if (PrintMiscellaneous && (Verbose || WizardMode)) {
+ perror("pthread_create()");
+ }
+ // Need to clean up stuff we've allocated so far
+ thread->set_osthread(NULL);
+ delete osthread;
+ if (lock) os::Linux::createThread_lock()->unlock();
+ return false;
+ }
+
+ // Store pthread info into the OSThread
+ osthread->set_pthread_id(tid);
+
+ // Wait until child thread is either initialized or aborted
+ {
+ Monitor* sync_with_child = osthread->startThread_lock();
+ MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
+ while ((state = osthread->get_state()) == ALLOCATED) {
+ sync_with_child->wait(Mutex::_no_safepoint_check_flag);
+ }
+ }
+
+ if (lock) {
+ os::Linux::createThread_lock()->unlock();
+ }
+ }
+
+ // Aborted due to thread limit being reached
+ if (state == ZOMBIE) {
+ thread->set_osthread(NULL);
+ delete osthread;
+ return false;
+ }
+
+ // The thread is returned suspended (in state INITIALIZED),
+ // and is started higher up in the call chain
+ assert(state == INITIALIZED, "race condition");
+ return true;
+}
+
+/////////////////////////////////////////////////////////////////////////////
+// attach existing thread
+
+// bootstrap the main thread
+bool os::create_main_thread(JavaThread* thread) {
+ assert(os::Linux::_main_thread == pthread_self(), "should be called inside main thread");
+ return create_attached_thread(thread);
+}
+
+bool os::create_attached_thread(JavaThread* thread) {
+#ifdef ASSERT
+ thread->verify_not_published();
+#endif
+
+ // Allocate the OSThread object
+ OSThread* osthread = new OSThread(NULL, NULL);
+
+ if (osthread == NULL) {
+ return false;
+ }
+
+ // Store pthread info into the OSThread
+ osthread->set_thread_id(os::Linux::gettid());
+ osthread->set_pthread_id(::pthread_self());
+
+ // initialize floating point control register
+ os::Linux::init_thread_fpu_state();
+
+ // Initial thread state is RUNNABLE
+ osthread->set_state(RUNNABLE);
+
+ thread->set_osthread(osthread);
+
+ if (UseNUMA) {
+ int lgrp_id = os::numa_get_group_id();
+ if (lgrp_id != -1) {
+ thread->set_lgrp_id(lgrp_id);
+ }
+ }
+
+ if (os::Linux::is_initial_thread()) {
+ // If current thread is initial thread, its stack is mapped on demand,
+ // see notes about MAP_GROWSDOWN. Here we try to force kernel to map
+ // the entire stack region to avoid SEGV in stack banging.
+ // It is also useful to get around the heap-stack-gap problem on SuSE
+ // kernel (see 4821821 for details). We first expand stack to the top
+ // of yellow zone, then enable stack yellow zone (order is significant,
+ // enabling yellow zone first will crash JVM on SuSE Linux), so there
+ // is no gap between the last two virtual memory regions.
+
+ JavaThread *jt = (JavaThread *)thread;
+ address addr = jt->stack_yellow_zone_base();
+ assert(addr != NULL, "initialization problem?");
+ assert(jt->stack_available(addr) > 0, "stack guard should not be enabled");
+
+ osthread->set_expanding_stack();
+ os::Linux::manually_expand_stack(jt, addr);
+ osthread->clear_expanding_stack();
+ }
+
+ // initialize signal mask for this thread
+ // and save the caller's signal mask
+ os::Linux::hotspot_sigmask(thread);
+
+ return true;
+}
+
+void os::pd_start_thread(Thread* thread) {
+ OSThread * osthread = thread->osthread();
+ assert(osthread->get_state() != INITIALIZED, "just checking");
+ Monitor* sync_with_child = osthread->startThread_lock();
+ MutexLockerEx ml(sync_with_child, Mutex::_no_safepoint_check_flag);
+ sync_with_child->notify();
+}
+
+// Free Linux resources related to the OSThread
+void os::free_thread(OSThread* osthread) {
+ assert(osthread != NULL, "osthread not set");
+
+ if (Thread::current()->osthread() == osthread) {
+ // Restore caller's signal mask
+ sigset_t sigmask = osthread->caller_sigmask();
+ pthread_sigmask(SIG_SETMASK, &sigmask, NULL);
+ }
+
+ delete osthread;
+}
+
+//////////////////////////////////////////////////////////////////////////////
+// thread local storage
+
+int os::allocate_thread_local_storage() {
+ pthread_key_t key;
+ int rslt = pthread_key_create(&key, NULL);
+ assert(rslt == 0, "cannot allocate thread local storage");
+ return (int)key;
+}
+
+// Note: This is currently not used by VM, as we don't destroy TLS key
+// on VM exit.
+void os::free_thread_local_storage(int index) {
+ int rslt = pthread_key_delete((pthread_key_t)index);
+ assert(rslt == 0, "invalid index");
+}
+
+void os::thread_local_storage_at_put(int index, void* value) {
+ int rslt = pthread_setspecific((pthread_key_t)index, value);
+ assert(rslt == 0, "pthread_setspecific failed");
+}
+
+extern "C" Thread* get_thread() {
+ return ThreadLocalStorage::thread();
+}
+
+//////////////////////////////////////////////////////////////////////////////
+// initial thread
+
+// Check if current thread is the initial thread, similar to Solaris thr_main.
+bool os::Linux::is_initial_thread(void) {
+ char dummy;
+ // If called before init complete, thread stack bottom will be null.
+ // Can be called if fatal error occurs before initialization.
+ if (initial_thread_stack_bottom() == NULL) return false;
+ assert(initial_thread_stack_bottom() != NULL &&
+ initial_thread_stack_size() != 0,
+ "os::init did not locate initial thread's stack region");
+ if ((address)&dummy >= initial_thread_stack_bottom() &&
+ (address)&dummy < initial_thread_stack_bottom() + initial_thread_stack_size())
+ return true;
+ else return false;
+}
+
+// Find the virtual memory area that contains addr
+static bool find_vma(address addr, address* vma_low, address* vma_high) {
+ FILE *fp = fopen("/proc/self/maps", "r");
+ if (fp) {
+ address low, high;
+ while (!feof(fp)) {
+ if (fscanf(fp, "%p-%p", &low, &high) == 2) {
+ if (low <= addr && addr < high) {
+ if (vma_low) *vma_low = low;
+ if (vma_high) *vma_high = high;
+ fclose (fp);
+ return true;
+ }
+ }
+ for (;;) {
+ int ch = fgetc(fp);
+ if (ch == EOF || ch == (int)'\n') break;
+ }
+ }
+ fclose(fp);
+ }
+ return false;
+}
+
+// Locate initial thread stack. This special handling of initial thread stack
+// is needed because pthread_getattr_np() on most (all?) Linux distros returns
+// bogus value for initial thread.
+void os::Linux::capture_initial_stack(size_t max_size) {
+ // stack size is the easy part, get it from RLIMIT_STACK
+ size_t stack_size;
+ struct rlimit rlim;
+ getrlimit(RLIMIT_STACK, &rlim);
+ stack_size = rlim.rlim_cur;
+
+ // 6308388: a bug in ld.so will relocate its own .data section to the
+ // lower end of primordial stack; reduce ulimit -s value a little bit
+ // so we won't install guard page on ld.so's data section.
+ stack_size -= 2 * page_size();
+
+ // 4441425: avoid crash with "unlimited" stack size on SuSE 7.1 or Redhat
+ // 7.1, in both cases we will get 2G in return value.
+ // 4466587: glibc 2.2.x compiled w/o "--enable-kernel=2.4.0" (RH 7.0,
+ // SuSE 7.2, Debian) can not handle alternate signal stack correctly
+ // for initial thread if its stack size exceeds 6M. Cap it at 2M,
+ // in case other parts in glibc still assumes 2M max stack size.
+ // FIXME: alt signal stack is gone, maybe we can relax this constraint?
+#ifndef IA64
+ if (stack_size > 2 * K * K) stack_size = 2 * K * K;
+#else
+ // Problem still exists RH7.2 (IA64 anyway) but 2MB is a little small
+ if (stack_size > 4 * K * K) stack_size = 4 * K * K;
+#endif
+
+ // Try to figure out where the stack base (top) is. This is harder.
+ //
+ // When an application is started, glibc saves the initial stack pointer in
+ // a global variable "__libc_stack_end", which is then used by system
+ // libraries. __libc_stack_end should be pretty close to stack top. The
+ // variable is available since the very early days. However, because it is
+ // a private interface, it could disappear in the future.
+ //
+ // Linux kernel saves start_stack information in /proc/<pid>/stat. Similar
+ // to __libc_stack_end, it is very close to stack top, but isn't the real
+ // stack top. Note that /proc may not exist if VM is running as a chroot
+ // program, so reading /proc/<pid>/stat could fail. Also the contents of
+ // /proc/<pid>/stat could change in the future (though unlikely).
+ //
+ // We try __libc_stack_end first. If that doesn't work, look for
+ // /proc/<pid>/stat. If neither of them works, we use current stack pointer
+ // as a hint, which should work well in most cases.
+
+ uintptr_t stack_start;
+
+ // try __libc_stack_end first
+ uintptr_t *p = (uintptr_t *)dlsym(RTLD_DEFAULT, "__libc_stack_end");
+ if (p && *p) {
+ stack_start = *p;
+ } else {
+ // see if we can get the start_stack field from /proc/self/stat
+ FILE *fp;
+ int pid;
+ char state;
+ int ppid;
+ int pgrp;
+ int session;
+ int nr;
+ int tpgrp;
+ unsigned long flags;
+ unsigned long minflt;
+ unsigned long cminflt;
+ unsigned long majflt;
+ unsigned long cmajflt;
+ unsigned long utime;
+ unsigned long stime;
+ long cutime;
+ long cstime;
+ long prio;
+ long nice;
+ long junk;
+ long it_real;
+ uintptr_t start;
+ uintptr_t vsize;
+ uintptr_t rss;
+ unsigned long rsslim;
+ uintptr_t scodes;
+ uintptr_t ecode;
+ int i;
+
+ // Figure what the primordial thread stack base is. Code is inspired
+ // by email from Hans Boehm. /proc/self/stat begins with current pid,
+ // followed by command name surrounded by parentheses, state, etc.
+ char stat[2048];
+ int statlen;
+
+ fp = fopen("/proc/self/stat", "r");
+ if (fp) {
+ statlen = fread(stat, 1, 2047, fp);
+ stat[statlen] = '\0';
+ fclose(fp);
+
+ // Skip pid and the command string. Note that we could be dealing with
+ // weird command names, e.g. user could decide to rename java launcher
+ // to "java 1.4.2 :)", then the stat file would look like
+ // 1234 (java 1.4.2 :)) R ... ...
+ // We don't really need to know the command string, just find the last
+ // occurrence of ")" and then start parsing from there. See bug 4726580.
+ char * s = strrchr(stat, ')');
+
+ i = 0;
+ if (s) {
+ // Skip blank chars
+ do s++; while (isspace(*s));
+
+ /* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 */
+ /* 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 */
+ i = sscanf(s, "%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld %lu %lu %ld %lu %lu %lu %lu",
+ &state, /* 3 %c */
+ &ppid, /* 4 %d */
+ &pgrp, /* 5 %d */
+ &session, /* 6 %d */
+ &nr, /* 7 %d */
+ &tpgrp, /* 8 %d */
+ &flags, /* 9 %lu */
+ &minflt, /* 10 %lu */
+ &cminflt, /* 11 %lu */
+ &majflt, /* 12 %lu */
+ &cmajflt, /* 13 %lu */
+ &utime, /* 14 %lu */
+ &stime, /* 15 %lu */
+ &cutime, /* 16 %ld */
+ &cstime, /* 17 %ld */
+ &prio, /* 18 %ld */
+ &nice, /* 19 %ld */
+ &junk, /* 20 %ld */
+ &it_real, /* 21 %ld */
+ &start, /* 22 %lu */
+ &vsize, /* 23 %lu */
+ &rss, /* 24 %ld */
+ &rsslim, /* 25 %lu */
+ &scodes, /* 26 %lu */
+ &ecode, /* 27 %lu */
+ &stack_start); /* 28 %lu */
+ }
+
+ if (i != 28 - 2) {
+ assert(false, "Bad conversion from /proc/self/stat");
+ // product mode - assume we are the initial thread, good luck in the
+ // embedded case.
+ warning("Can't detect initial thread stack location - bad conversion");
+ stack_start = (uintptr_t) &rlim;
+ }
+ } else {
+ // For some reason we can't open /proc/self/stat (for example, running on
+ // FreeBSD with a Linux emulator, or inside chroot), this should work for
+ // most cases, so don't abort:
+ warning("Can't detect initial thread stack location - no /proc/self/stat");
+ stack_start = (uintptr_t) &rlim;
+ }
+ }
+
+ // Now we have a pointer (stack_start) very close to the stack top, the
+ // next thing to do is to figure out the exact location of stack top. We
+ // can find out the virtual memory area that contains stack_start by
+ // reading /proc/self/maps, it should be the last vma in /proc/self/maps,
+ // and its upper limit is the real stack top. (again, this would fail if
+ // running inside chroot, because /proc may not exist.)
+
+ uintptr_t stack_top;
+ address low, high;
+ if (find_vma((address)stack_start, &low, &high)) {
+ // success, "high" is the true stack top. (ignore "low", because initial
+ // thread stack grows on demand, its real bottom is high - RLIMIT_STACK.)
+ stack_top = (uintptr_t)high;
+ } else {
+ // failed, likely because /proc/self/maps does not exist
+ warning("Can't detect initial thread stack location - find_vma failed");
+ // best effort: stack_start is normally within a few pages below the real
+ // stack top, use it as stack top, and reduce stack size so we won't put
+ // guard page outside stack.
+ stack_top = stack_start;
+ stack_size -= 16 * page_size();
+ }
+
+ // stack_top could be partially down the page so align it
+ stack_top = align_size_up(stack_top, page_size());
+
+ if (max_size && stack_size > max_size) {
+ _initial_thread_stack_size = max_size;
+ } else {
+ _initial_thread_stack_size = stack_size;
+ }
+
+ _initial_thread_stack_size = align_size_down(_initial_thread_stack_size, page_size());
+ _initial_thread_stack_bottom = (address)stack_top - _initial_thread_stack_size;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// time support
+
+// Time since start-up in seconds to a fine granularity.
+// Used by VMSelfDestructTimer and the MemProfiler.
+double os::elapsedTime() {
+
+ return (double)(os::elapsed_counter()) * 0.000001;
+}
+
+jlong os::elapsed_counter() {
+ timeval time;
+ int status = gettimeofday(&time, NULL);
+ return jlong(time.tv_sec) * 1000 * 1000 + jlong(time.tv_usec) - initial_time_count;
+}
+
+jlong os::elapsed_frequency() {
+ return (1000 * 1000);
+}
+
+jlong os::timeofday() {
+ timeval time;
+ int status = gettimeofday(&time, NULL);
+ assert(status != -1, "linux error");
+ return jlong(time.tv_sec) * 1000 + jlong(time.tv_usec / 1000);
+}
+
+// Must return millis since Jan 1 1970 for JVM_CurrentTimeMillis
+// _use_global_time is only set if CacheTimeMillis is true
+jlong os::javaTimeMillis() {
+ return (_use_global_time ? read_global_time() : timeofday());
+}
+
+#ifndef CLOCK_MONOTONIC
+#define CLOCK_MONOTONIC (1)
+#endif
+
+void os::Linux::clock_init() {
+ // we do dlopen's in this particular order due to bug in linux
+ // dynamical loader (see 6348968) leading to crash on exit
+ void* handle = dlopen("librt.so.1", RTLD_LAZY);
+ if (handle == NULL) {
+ handle = dlopen("librt.so", RTLD_LAZY);
+ }
+
+ if (handle) {
+ int (*clock_getres_func)(clockid_t, struct timespec*) =
+ (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_getres");
+ int (*clock_gettime_func)(clockid_t, struct timespec*) =
+ (int(*)(clockid_t, struct timespec*))dlsym(handle, "clock_gettime");
+ if (clock_getres_func && clock_gettime_func) {
+ // See if monotonic clock is supported by the kernel. Note that some
+ // early implementations simply return kernel jiffies (updated every
+ // 1/100 or 1/1000 second). It would be bad to use such a low res clock
+ // for nano time (though the monotonic property is still nice to have).
+ // It's fixed in newer kernels, however clock_getres() still returns
+ // 1/HZ. We check if clock_getres() works, but will ignore its reported
+ // resolution for now. Hopefully as people move to new kernels, this
+ // won't be a problem.
+ struct timespec res;
+ struct timespec tp;
+ if (clock_getres_func (CLOCK_MONOTONIC, &res) == 0 &&
+ clock_gettime_func(CLOCK_MONOTONIC, &tp) == 0) {
+ // yes, monotonic clock is supported
+ _clock_gettime = clock_gettime_func;
+ } else {
+ // close librt if there is no monotonic clock
+ dlclose(handle);
+ }
+ }
+ }
+}
+
+#ifndef SYS_clock_getres
+
+#if defined(IA32) || defined(AMD64)
+#define SYS_clock_getres IA32_ONLY(266) AMD64_ONLY(229)
+#else
+#error Value of SYS_clock_getres not known on this platform
+#endif
+
+#endif
+
+#define sys_clock_getres(x,y) ::syscall(SYS_clock_getres, x, y)
+
+void os::Linux::fast_thread_clock_init() {
+ if (!UseLinuxPosixThreadCPUClocks) {
+ return;
+ }
+ clockid_t clockid;
+ struct timespec tp;
+ int (*pthread_getcpuclockid_func)(pthread_t, clockid_t *) =
+ (int(*)(pthread_t, clockid_t *)) dlsym(RTLD_DEFAULT, "pthread_getcpuclockid");
+
+ // Switch to using fast clocks for thread cpu time if
+ // the sys_clock_getres() returns 0 error code.
+ // Note, that some kernels may support the current thread
+ // clock (CLOCK_THREAD_CPUTIME_ID) but not the clocks
+ // returned by the pthread_getcpuclockid().
+ // If the fast Posix clocks are supported then the sys_clock_getres()
+ // must return at least tp.tv_sec == 0 which means a resolution
+ // better than 1 sec. This is extra check for reliability.
+
+ if(pthread_getcpuclockid_func &&
+ pthread_getcpuclockid_func(_main_thread, &clockid) == 0 &&
+ sys_clock_getres(clockid, &tp) == 0 && tp.tv_sec == 0) {
+
+ _supports_fast_thread_cpu_time = true;
+ _pthread_getcpuclockid = pthread_getcpuclockid_func;
+ }
+}
+
+jlong os::javaTimeNanos() {
+ if (Linux::supports_monotonic_clock()) {
+ struct timespec tp;
+ int status = Linux::clock_gettime(CLOCK_MONOTONIC, &tp);
+ assert(status == 0, "gettime error");
+ jlong result = jlong(tp.tv_sec) * (1000 * 1000 * 1000) + jlong(tp.tv_nsec);
+ return result;
+ } else {
+ timeval time;
+ int status = gettimeofday(&time, NULL);
+ assert(status != -1, "linux error");
+ jlong usecs = jlong(time.tv_sec) * (1000 * 1000) + jlong(time.tv_usec);
+ return 1000 * usecs;
+ }
+}
+
+void os::javaTimeNanos_info(jvmtiTimerInfo *info_ptr) {
+ if (Linux::supports_monotonic_clock()) {
+ info_ptr->max_value = ALL_64_BITS;
+
+ // CLOCK_MONOTONIC - amount of time since some arbitrary point in the past
+ info_ptr->may_skip_backward = false; // not subject to resetting or drifting
+ info_ptr->may_skip_forward = false; // not subject to resetting or drifting
+ } else {
+ // gettimeofday - based on time in seconds since the Epoch thus does not wrap
+ info_ptr->max_value = ALL_64_BITS;
+
+ // gettimeofday is a real time clock so it skips
+ info_ptr->may_skip_backward = true;
+ info_ptr->may_skip_forward = true;
+ }
+
+ info_ptr->kind = JVMTI_TIMER_ELAPSED; // elapsed not CPU time
+}
+
+// Return the real, user, and system times in seconds from an
+// arbitrary fixed point in the past.
+bool os::getTimesSecs(double* process_real_time,
+ double* process_user_time,
+ double* process_system_time) {
+ struct tms ticks;
+ clock_t real_ticks = times(&ticks);
+
+ if (real_ticks == (clock_t) (-1)) {
+ return false;
+ } else {
+ double ticks_per_second = (double) clock_tics_per_sec;
+ *process_user_time = ((double) ticks.tms_utime) / ticks_per_second;
+ *process_system_time = ((double) ticks.tms_stime) / ticks_per_second;
+ *process_real_time = ((double) real_ticks) / ticks_per_second;
+
+ return true;
+ }
+}
+
+
+char * os::local_time_string(char *buf, size_t buflen) {
+ struct tm t;
+ time_t long_time;
+ time(&long_time);
+ localtime_r(&long_time, &t);
+ jio_snprintf(buf, buflen, "%d-%02d-%02d %02d:%02d:%02d",
+ t.tm_year + 1900, t.tm_mon + 1, t.tm_mday,
+ t.tm_hour, t.tm_min, t.tm_sec);
+ return buf;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// runtime exit support
+
+// Note: os::shutdown() might be called very early during initialization, or
+// called from signal handler. Before adding something to os::shutdown(), make
+// sure it is async-safe and can handle partially initialized VM.
+void os::shutdown() {
+
+ // allow PerfMemory to attempt cleanup of any persistent resources
+ perfMemory_exit();
+
+ // needs to remove object in file system
+ AttachListener::abort();
+
+ // flush buffered output, finish log files
+ ostream_abort();
+
+ // Check for abort hook
+ abort_hook_t abort_hook = Arguments::abort_hook();
+ if (abort_hook != NULL) {
+ abort_hook();
+ }
+
+}
+
+// Note: os::abort() might be called very early during initialization, or
+// called from signal handler. Before adding something to os::abort(), make
+// sure it is async-safe and can handle partially initialized VM.
+void os::abort(bool dump_core) {
+ os::shutdown();
+ if (dump_core) {
+#ifndef PRODUCT
+ fdStream out(defaultStream::output_fd());
+ out.print_raw("Current thread is ");
+ char buf[16];
+ jio_snprintf(buf, sizeof(buf), UINTX_FORMAT, os::current_thread_id());
+ out.print_raw_cr(buf);
+ out.print_raw_cr("Dumping core ...");
+#endif
+ ::abort(); // dump core
+ }
+
+ ::exit(1);
+}
+
+// Die immediately, no exit hook, no abort hook, no cleanup.
+void os::die() {
+ // _exit() on LinuxThreads only kills current thread
+ ::abort();
+}
+
+// unused on linux for now.
+void os::set_error_file(const char *logfile) {}
+
+intx os::current_thread_id() { return (intx)pthread_self(); }
+int os::current_process_id() {
+
+ // Under the old linux thread library, linux gives each thread
+ // its own process id. Because of this each thread will return
+ // a different pid if this method were to return the result
+ // of getpid(2). Linux provides no api that returns the pid
+ // of the launcher thread for the vm. This implementation
+ // returns a unique pid, the pid of the launcher thread
+ // that starts the vm 'process'.
+
+ // Under the NPTL, getpid() returns the same pid as the
+ // launcher thread rather than a unique pid per thread.
+ // Use gettid() if you want the old pre NPTL behaviour.
+
+ // if you are looking for the result of a call to getpid() that
+ // returns a unique pid for the calling thread, then look at the
+ // OSThread::thread_id() method in osThread_linux.hpp file
+
+ return (int)(_initial_pid ? _initial_pid : getpid());
+}
+
+// DLL functions
+
+const char* os::dll_file_extension() { return ".so"; }
+
+const char* os::get_temp_directory() { return "/tmp/"; }
+
+const char* os::get_current_directory(char *buf, int buflen) {
+ return getcwd(buf, buflen);
+}
+
+// check if addr is inside libjvm[_g].so
+bool os::address_is_in_vm(address addr) {
+ static address libjvm_base_addr;
+ Dl_info dlinfo;
+
+ if (libjvm_base_addr == NULL) {
+ dladdr(CAST_FROM_FN_PTR(void *, os::address_is_in_vm), &dlinfo);
+ libjvm_base_addr = (address)dlinfo.dli_fbase;
+ assert(libjvm_base_addr !=NULL, "Cannot obtain base address for libjvm");
+ }
+
+ if (dladdr((void *)addr, &dlinfo)) {
+ if (libjvm_base_addr == (address)dlinfo.dli_fbase) return true;
+ }
+
+ return false;
+}
+
+bool os::dll_address_to_function_name(address addr, char *buf,
+ int buflen, int *offset) {
+ Dl_info dlinfo;
+
+ if (dladdr((void*)addr, &dlinfo) && dlinfo.dli_sname != NULL) {
+ if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_sname);
+ if (offset) *offset = addr - (address)dlinfo.dli_saddr;
+ return true;
+ } else {
+ if (buf) buf[0] = '\0';
+ if (offset) *offset = -1;
+ return false;
+ }
+}
+
+struct _address_to_library_name {
+ address addr; // input : memory address
+ size_t buflen; // size of fname
+ char* fname; // output: library name
+ address base; // library base addr
+};
+
+static int address_to_library_name_callback(struct dl_phdr_info *info,
+ size_t size, void *data) {
+ int i;
+ bool found = false;
+ address libbase = NULL;
+ struct _address_to_library_name * d = (struct _address_to_library_name *)data;
+
+ // iterate through all loadable segments
+ for (i = 0; i < info->dlpi_phnum; i++) {
+ address segbase = (address)(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
+ if (info->dlpi_phdr[i].p_type == PT_LOAD) {
+ // base address of a library is the lowest address of its loaded
+ // segments.
+ if (libbase == NULL || libbase > segbase) {
+ libbase = segbase;
+ }
+ // see if 'addr' is within current segment
+ if (segbase <= d->addr &&
+ d->addr < segbase + info->dlpi_phdr[i].p_memsz) {
+ found = true;
+ }
+ }
+ }
+
+ // dlpi_name is NULL or empty if the ELF file is executable, return 0
+ // so dll_address_to_library_name() can fall through to use dladdr() which
+ // can figure out executable name from argv[0].
+ if (found && info->dlpi_name && info->dlpi_name[0]) {
+ d->base = libbase;
+ if (d->fname) {
+ jio_snprintf(d->fname, d->buflen, "%s", info->dlpi_name);
+ }
+ return 1;
+ }
+ return 0;
+}
+
+bool os::dll_address_to_library_name(address addr, char* buf,
+ int buflen, int* offset) {
+ Dl_info dlinfo;
+ struct _address_to_library_name data;
+
+ // There is a bug in old glibc dladdr() implementation that it could resolve
+ // to wrong library name if the .so file has a base address != NULL. Here
+ // we iterate through the program headers of all loaded libraries to find
+ // out which library 'addr' really belongs to. This workaround can be
+ // removed once the minimum requirement for glibc is moved to 2.3.x.
+ data.addr = addr;
+ data.fname = buf;
+ data.buflen = buflen;
+ data.base = NULL;
+ int rslt = dl_iterate_phdr(address_to_library_name_callback, (void *)&data);
+
+ if (rslt) {
+ // buf already contains library name
+ if (offset) *offset = addr - data.base;
+ return true;
+ } else if (dladdr((void*)addr, &dlinfo)){
+ if (buf) jio_snprintf(buf, buflen, "%s", dlinfo.dli_fname);
+ if (offset) *offset = addr - (address)dlinfo.dli_fbase;
+ return true;
+ } else {
+ if (buf) buf[0] = '\0';
+ if (offset) *offset = -1;
+ return false;
+ }
+}
+
+ // Loads .dll/.so and
+ // in case of error it checks if .dll/.so was built for the
+ // same architecture as Hotspot is running on
+
+void * os::dll_load(const char *filename, char *ebuf, int ebuflen)
+{
+ void * result= ::dlopen(filename, RTLD_LAZY);
+ if (result != NULL) {
+ // Successful loading
+ return result;
+ }
+
+ Elf32_Ehdr elf_head;
+
+ // Read system error message into ebuf
+ // It may or may not be overwritten below
+ ::strncpy(ebuf, ::dlerror(), ebuflen-1);
+ ebuf[ebuflen-1]='\0';
+ int diag_msg_max_length=ebuflen-strlen(ebuf);
+ char* diag_msg_buf=ebuf+strlen(ebuf);
+
+ if (diag_msg_max_length==0) {
+ // No more space in ebuf for additional diagnostics message
+ return NULL;
+ }
+
+
+ int file_descriptor= ::open(filename, O_RDONLY | O_NONBLOCK);
+
+ if (file_descriptor < 0) {
+ // Can't open library, report dlerror() message
+ return NULL;
+ }
+
+ bool failed_to_read_elf_head=
+ (sizeof(elf_head)!=
+ (::read(file_descriptor, &elf_head,sizeof(elf_head)))) ;
+
+ ::close(file_descriptor);
+ if (failed_to_read_elf_head) {
+ // file i/o error - report dlerror() msg
+ return NULL;
+ }
+
+ typedef struct {
+ Elf32_Half code; // Actual value as defined in elf.h
+ Elf32_Half compat_class; // Compatibility of archs at VM's sense
+ char elf_class; // 32 or 64 bit
+ char endianess; // MSB or LSB
+ char* name; // String representation
+ } arch_t;
+
+ #ifndef EM_486
+ #define EM_486 6 /* Intel 80486 */
+ #endif
+
+ static const arch_t arch_array[]={
+ {EM_386, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
+ {EM_486, EM_386, ELFCLASS32, ELFDATA2LSB, (char*)"IA 32"},
+ {EM_IA_64, EM_IA_64, ELFCLASS64, ELFDATA2LSB, (char*)"IA 64"},
+ {EM_X86_64, EM_X86_64, ELFCLASS64, ELFDATA2LSB, (char*)"AMD 64"},
+ {EM_SPARC, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
+ {EM_SPARC32PLUS, EM_SPARC, ELFCLASS32, ELFDATA2MSB, (char*)"Sparc 32"},
+ {EM_SPARCV9, EM_SPARCV9, ELFCLASS64, ELFDATA2MSB, (char*)"Sparc v9 64"},
+ {EM_PPC, EM_PPC, ELFCLASS32, ELFDATA2MSB, (char*)"Power PC 32"},
+ {EM_PPC64, EM_PPC64, ELFCLASS64, ELFDATA2MSB, (char*)"Power PC 64"}
+ };
+
+ #if (defined IA32)
+ static Elf32_Half running_arch_code=EM_386;
+ #elif (defined AMD64)
+ static Elf32_Half running_arch_code=EM_X86_64;
+ #elif (defined IA64)
+ static Elf32_Half running_arch_code=EM_IA_64;
+ #elif (defined __sparc) && (defined _LP64)
+ static Elf32_Half running_arch_code=EM_SPARCV9;
+ #elif (defined __sparc) && (!defined _LP64)
+ static Elf32_Half running_arch_code=EM_SPARC;
+ #elif (defined __powerpc64__)
+ static Elf32_Half running_arch_code=EM_PPC64;
+ #elif (defined __powerpc__)
+ static Elf32_Half running_arch_code=EM_PPC;
+ #else
+ #error Method os::dll_load requires that one of following is defined:\
+ IA32, AMD64, IA64, __sparc, __powerpc__
+ #endif
+
+ // Identify compatability class for VM's architecture and library's architecture
+ // Obtain string descriptions for architectures
+
+ arch_t lib_arch={elf_head.e_machine,0,elf_head.e_ident[EI_CLASS], elf_head.e_ident[EI_DATA], NULL};
+ int running_arch_index=-1;
+
+ for (unsigned int i=0 ; i < ARRAY_SIZE(arch_array) ; i++ ) {
+ if (running_arch_code == arch_array[i].code) {
+ running_arch_index = i;
+ }
+ if (lib_arch.code == arch_array[i].code) {
+ lib_arch.compat_class = arch_array[i].compat_class;
+ lib_arch.name = arch_array[i].name;
+ }
+ }
+
+ assert(running_arch_index != -1,
+ "Didn't find running architecture code (running_arch_code) in arch_array");
+ if (running_arch_index == -1) {
+ // Even though running architecture detection failed
+ // we may still continue with reporting dlerror() message
+ return NULL;
+ }
+
+ if (lib_arch.endianess != arch_array[running_arch_index].endianess) {
+ ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: endianness mismatch)");
+ return NULL;
+ }
+
+ if (lib_arch.elf_class != arch_array[running_arch_index].elf_class) {
+ ::snprintf(diag_msg_buf, diag_msg_max_length-1," (Possible cause: architecture word width mismatch)");
+ return NULL;
+ }
+
+ if (lib_arch.compat_class != arch_array[running_arch_index].compat_class) {
+ if ( lib_arch.name!=NULL ) {
+ ::snprintf(diag_msg_buf, diag_msg_max_length-1,
+ " (Possible cause: can't load %s-bit .so on a %s-bit platform)",
+ lib_arch.name, arch_array[running_arch_index].name);
+ } else {
+ ::snprintf(diag_msg_buf, diag_msg_max_length-1,
+ " (Possible cause: can't load this .so (machine code=0x%x) on a %s-bit platform)",
+ lib_arch.code,
+ arch_array[running_arch_index].name);
+ }
+ }
+
+ return NULL;
+}
+
+
+
+
+bool _print_ascii_file(const char* filename, outputStream* st) {
+ int fd = open(filename, O_RDONLY);
+ if (fd == -1) {
+ return false;
+ }
+
+ char buf[32];
+ int bytes;
+ while ((bytes = read(fd, buf, sizeof(buf))) > 0) {
+ st->print_raw(buf, bytes);
+ }
+
+ close(fd);
+
+ return true;
+}
+
+void os::print_dll_info(outputStream *st) {
+ st->print_cr("Dynamic libraries:");
+
+ char fname[32];
+ pid_t pid = os::Linux::gettid();
+
+ jio_snprintf(fname, sizeof(fname), "/proc/%d/maps", pid);
+
+ if (!_print_ascii_file(fname, st)) {
+ st->print("Can not get library information for pid = %d\n", pid);
+ }
+}
+
+
+void os::print_os_info(outputStream* st) {
+ st->print("OS:");
+
+ // Try to identify popular distros.
+ // Most Linux distributions have /etc/XXX-release file, which contains
+ // the OS version string. Some have more than one /etc/XXX-release file
+ // (e.g. Mandrake has both /etc/mandrake-release and /etc/redhat-release.),
+ // so the order is important.
+ if (!_print_ascii_file("/etc/mandrake-release", st) &&
+ !_print_ascii_file("/etc/sun-release", st) &&
+ !_print_ascii_file("/etc/redhat-release", st) &&
+ !_print_ascii_file("/etc/SuSE-release", st) &&
+ !_print_ascii_file("/etc/turbolinux-release", st) &&
+ !_print_ascii_file("/etc/gentoo-release", st) &&
+ !_print_ascii_file("/etc/debian_version", st)) {
+ st->print("Linux");
+ }
+ st->cr();
+
+ // kernel
+ st->print("uname:");
+ struct utsname name;
+ uname(&name);
+ st->print(name.sysname); st->print(" ");
+ st->print(name.release); st->print(" ");
+ st->print(name.version); st->print(" ");
+ st->print(name.machine);
+ st->cr();
+
+ // Print warning if unsafe chroot environment detected
+ if (unsafe_chroot_detected) {
+ st->print("WARNING!! ");
+ st->print_cr(unstable_chroot_error);
+ }
+
+ // libc, pthread
+ st->print("libc:");
+ st->print(os::Linux::glibc_version()); st->print(" ");
+ st->print(os::Linux::libpthread_version()); st->print(" ");
+ if (os::Linux::is_LinuxThreads()) {
+ st->print("(%s stack)", os::Linux::is_floating_stack() ? "floating" : "fixed");
+ }
+ st->cr();
+
+ // rlimit
+ st->print("rlimit:");
+ struct rlimit rlim;
+
+ st->print(" STACK ");
+ getrlimit(RLIMIT_STACK, &rlim);
+ if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
+ else st->print("%uk", rlim.rlim_cur >> 10);
+
+ st->print(", CORE ");
+ getrlimit(RLIMIT_CORE, &rlim);
+ if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
+ else st->print("%uk", rlim.rlim_cur >> 10);
+
+ st->print(", NPROC ");
+ getrlimit(RLIMIT_NPROC, &rlim);
+ if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
+ else st->print("%d", rlim.rlim_cur);
+
+ st->print(", NOFILE ");
+ getrlimit(RLIMIT_NOFILE, &rlim);
+ if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
+ else st->print("%d", rlim.rlim_cur);
+
+ st->print(", AS ");
+ getrlimit(RLIMIT_AS, &rlim);
+ if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
+ else st->print("%uk", rlim.rlim_cur >> 10);
+ st->cr();
+
+ // load average
+ st->print("load average:");
+ double loadavg[3];
+ os::loadavg(loadavg, 3);
+ st->print("%0.02f %0.02f %0.02f", loadavg[0], loadavg[1], loadavg[2]);
+ st->cr();
+}
+
+void os::print_memory_info(outputStream* st) {
+
+ st->print("Memory:");
+ st->print(" %dk page", os::vm_page_size()>>10);
+
+ // values in struct sysinfo are "unsigned long"
+ struct sysinfo si;
+ sysinfo(&si);
+
+ st->print(", physical " UINT64_FORMAT "k",
+ os::physical_memory() >> 10);
+ st->print("(" UINT64_FORMAT "k free)",
+ os::available_memory() >> 10);
+ st->print(", swap " UINT64_FORMAT "k",
+ ((jlong)si.totalswap * si.mem_unit) >> 10);
+ st->print("(" UINT64_FORMAT "k free)",
+ ((jlong)si.freeswap * si.mem_unit) >> 10);
+ st->cr();
+}
+
+// Taken from /usr/include/bits/siginfo.h Supposed to be architecture specific
+// but they're the same for all the linux arch that we support
+// and they're the same for solaris but there's no common place to put this.
+const char *ill_names[] = { "ILL0", "ILL_ILLOPC", "ILL_ILLOPN", "ILL_ILLADR",
+ "ILL_ILLTRP", "ILL_PRVOPC", "ILL_PRVREG",
+ "ILL_COPROC", "ILL_BADSTK" };
+
+const char *fpe_names[] = { "FPE0", "FPE_INTDIV", "FPE_INTOVF", "FPE_FLTDIV",
+ "FPE_FLTOVF", "FPE_FLTUND", "FPE_FLTRES",
+ "FPE_FLTINV", "FPE_FLTSUB", "FPE_FLTDEN" };
+
+const char *segv_names[] = { "SEGV0", "SEGV_MAPERR", "SEGV_ACCERR" };
+
+const char *bus_names[] = { "BUS0", "BUS_ADRALN", "BUS_ADRERR", "BUS_OBJERR" };
+
+void os::print_siginfo(outputStream* st, void* siginfo) {
+ st->print("siginfo:");
+
+ const int buflen = 100;
+ char buf[buflen];
+ siginfo_t *si = (siginfo_t*)siginfo;
+ st->print("si_signo=%s: ", os::exception_name(si->si_signo, buf, buflen));
+ if (si->si_errno != 0 && strerror_r(si->si_errno, buf, buflen) == 0) {
+ st->print("si_errno=%s", buf);
+ } else {
+ st->print("si_errno=%d", si->si_errno);
+ }
+ const int c = si->si_code;
+ assert(c > 0, "unexpected si_code");
+ switch (si->si_signo) {
+ case SIGILL:
+ st->print(", si_code=%d (%s)", c, c > 8 ? "" : ill_names[c]);
+ st->print(", si_addr=" PTR_FORMAT, si->si_addr);
+ break;
+ case SIGFPE:
+ st->print(", si_code=%d (%s)", c, c > 9 ? "" : fpe_names[c]);
+ st->print(", si_addr=" PTR_FORMAT, si->si_addr);
+ break;
+ case SIGSEGV:
+ st->print(", si_code=%d (%s)", c, c > 2 ? "" : segv_names[c]);
+ st->print(", si_addr=" PTR_FORMAT, si->si_addr);
+ break;
+ case SIGBUS:
+ st->print(", si_code=%d (%s)", c, c > 3 ? "" : bus_names[c]);
+ st->print(", si_addr=" PTR_FORMAT, si->si_addr);
+ break;
+ default:
+ st->print(", si_code=%d", si->si_code);
+ // no si_addr
+ }
+
+ if ((si->si_signo == SIGBUS || si->si_signo == SIGSEGV) &&
+ UseSharedSpaces) {
+ FileMapInfo* mapinfo = FileMapInfo::current_info();
+ if (mapinfo->is_in_shared_space(si->si_addr)) {
+ st->print("\n\nError accessing class data sharing archive." \
+ " Mapped file inaccessible during execution, " \
+ " possible disk/network problem.");
+ }
+ }
+ st->cr();
+}
+
+
+static void print_signal_handler(outputStream* st, int sig,
+ char* buf, size_t buflen);
+
+void os::print_signal_handlers(outputStream* st, char* buf, size_t buflen) {
+ st->print_cr("Signal Handlers:");
+ print_signal_handler(st, SIGSEGV, buf, buflen);
+ print_signal_handler(st, SIGBUS , buf, buflen);
+ print_signal_handler(st, SIGFPE , buf, buflen);
+ print_signal_handler(st, SIGPIPE, buf, buflen);
+ print_signal_handler(st, SIGXFSZ, buf, buflen);
+ print_signal_handler(st, SIGILL , buf, buflen);
+ print_signal_handler(st, INTERRUPT_SIGNAL, buf, buflen);
+ print_signal_handler(st, SR_signum, buf, buflen);
+ print_signal_handler(st, SHUTDOWN1_SIGNAL, buf, buflen);
+ print_signal_handler(st, SHUTDOWN2_SIGNAL , buf, buflen);
+ print_signal_handler(st, SHUTDOWN3_SIGNAL , buf, buflen);
+ print_signal_handler(st, BREAK_SIGNAL, buf, buflen);
+}
+
+static char saved_jvm_path[MAXPATHLEN] = {0};
+
+// Find the full path to the current module, libjvm.so or libjvm_g.so
+void os::jvm_path(char *buf, jint len) {
+ // Error checking.
+ if (len < MAXPATHLEN) {
+ assert(false, "must use a large-enough buffer");
+ buf[0] = '\0';
+ return;
+ }
+ // Lazy resolve the path to current module.
+ if (saved_jvm_path[0] != 0) {
+ strcpy(buf, saved_jvm_path);
+ return;
+ }
+
+ char dli_fname[MAXPATHLEN];
+ bool ret = dll_address_to_library_name(
+ CAST_FROM_FN_PTR(address, os::jvm_path),
+ dli_fname, sizeof(dli_fname), NULL);
+ assert(ret != 0, "cannot locate libjvm");
+ realpath(dli_fname, buf);
+
+ if (strcmp(Arguments::sun_java_launcher(), "gamma") == 0) {
+ // Support for the gamma launcher. Typical value for buf is
+ // "<JAVA_HOME>/jre/lib/<arch>/<vmtype>/libjvm.so". If "/jre/lib/" appears at
+ // the right place in the string, then assume we are installed in a JDK and
+ // we're done. Otherwise, check for a JAVA_HOME environment variable and fix
+ // up the path so it looks like libjvm.so is installed there (append a
+ // fake suffix hotspot/libjvm.so).
+ const char *p = buf + strlen(buf) - 1;
+ for (int count = 0; p > buf && count < 5; ++count) {
+ for (--p; p > buf && *p != '/'; --p)
+ /* empty */ ;
+ }
+
+ if (strncmp(p, "/jre/lib/", 9) != 0) {
+ // Look for JAVA_HOME in the environment.
+ char* java_home_var = ::getenv("JAVA_HOME");
+ if (java_home_var != NULL && java_home_var[0] != 0) {
+ // Check the current module name "libjvm.so" or "libjvm_g.so".
+ p = strrchr(buf, '/');
+ assert(strstr(p, "/libjvm") == p, "invalid library name");
+ p = strstr(p, "_g") ? "_g" : "";
+
+ realpath(java_home_var, buf);
+ sprintf(buf + strlen(buf), "/jre/lib/%s", cpu_arch);
+ if (0 == access(buf, F_OK)) {
+ // Use current module name "libjvm[_g].so" instead of
+ // "libjvm"debug_only("_g")".so" since for fastdebug version
+ // we should have "libjvm.so" but debug_only("_g") adds "_g"!
+ // It is used when we are choosing the HPI library's name
+ // "libhpi[_g].so" in hpi::initialize_get_interface().
+ sprintf(buf + strlen(buf), "/hotspot/libjvm%s.so", p);
+ } else {
+ // Go back to path of .so
+ realpath(dli_fname, buf);
+ }
+ }
+ }
+ }
+
+ strcpy(saved_jvm_path, buf);
+}
+
+void os::print_jni_name_prefix_on(outputStream* st, int args_size) {
+ // no prefix required, not even "_"
+}
+
+void os::print_jni_name_suffix_on(outputStream* st, int args_size) {
+ // no suffix required
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// sun.misc.Signal support
+
+static volatile jint sigint_count = 0;
+
+static void
+UserHandler(int sig, void *siginfo, void *context) {
+ // 4511530 - sem_post is serialized and handled by the manager thread. When
+ // the program is interrupted by Ctrl-C, SIGINT is sent to every thread. We
+ // don't want to flood the manager thread with sem_post requests.
+ if (sig == SIGINT && Atomic::add(1, &sigint_count) > 1)
+ return;
+
+ // Ctrl-C is pressed during error reporting, likely because the error
+ // handler fails to abort. Let VM die immediately.
+ if (sig == SIGINT && is_error_reported()) {
+ os::die();
+ }
+
+ os::signal_notify(sig);
+}
+
+void* os::user_handler() {
+ return CAST_FROM_FN_PTR(void*, UserHandler);
+}
+
+extern "C" {
+ typedef void (*sa_handler_t)(int);
+ typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
+}
+
+void* os::signal(int signal_number, void* handler) {
+ struct sigaction sigAct, oldSigAct;
+
+ sigfillset(&(sigAct.sa_mask));
+ sigAct.sa_flags = SA_RESTART|SA_SIGINFO;
+ sigAct.sa_handler = CAST_TO_FN_PTR(sa_handler_t, handler);
+
+ if (sigaction(signal_number, &sigAct, &oldSigAct)) {
+ // -1 means registration failed
+ return (void *)-1;
+ }
+
+ return CAST_FROM_FN_PTR(void*, oldSigAct.sa_handler);
+}
+
+void os::signal_raise(int signal_number) {
+ ::raise(signal_number);
+}
+
+/*
+ * The following code is moved from os.cpp for making this
+ * code platform specific, which it is by its very nature.
+ */
+
+// Will be modified when max signal is changed to be dynamic
+int os::sigexitnum_pd() {
+ return NSIG;
+}
+
+// a counter for each possible signal value
+static volatile jint pending_signals[NSIG+1] = { 0 };
+
+// Linux(POSIX) specific hand shaking semaphore.
+static sem_t sig_sem;
+
+void os::signal_init_pd() {
+ // Initialize signal structures
+ ::memset((void*)pending_signals, 0, sizeof(pending_signals));
+
+ // Initialize signal semaphore
+ ::sem_init(&sig_sem, 0, 0);
+}
+
+void os::signal_notify(int sig) {
+ Atomic::inc(&pending_signals[sig]);
+ ::sem_post(&sig_sem);
+}
+
+static int check_pending_signals(bool wait) {
+ Atomic::store(0, &sigint_count);
+ for (;;) {
+ for (int i = 0; i < NSIG + 1; i++) {
+ jint n = pending_signals[i];
+ if (n > 0 && n == Atomic::cmpxchg(n - 1, &pending_signals[i], n)) {
+ return i;
+ }
+ }
+ if (!wait) {
+ return -1;
+ }
+ JavaThread *thread = JavaThread::current();
+ ThreadBlockInVM tbivm(thread);
+
+ bool threadIsSuspended;
+ do {
+ thread->set_suspend_equivalent();
+ // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
+ ::sem_wait(&sig_sem);
+
+ // were we externally suspended while we were waiting?
+ threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
+ if (threadIsSuspended) {
+ //
+ // The semaphore has been incremented, but while we were waiting
+ // another thread suspended us. We don't want to continue running
+ // while suspended because that would surprise the thread that
+ // suspended us.
+ //
+ ::sem_post(&sig_sem);
+
+ thread->java_suspend_self();
+ }
+ } while (threadIsSuspended);
+ }
+}
+
+int os::signal_lookup() {
+ return check_pending_signals(false);
+}
+
+int os::signal_wait() {
+ return check_pending_signals(true);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Virtual Memory
+
+int os::vm_page_size() {
+ // Seems redundant as all get out
+ assert(os::Linux::page_size() != -1, "must call os::init");
+ return os::Linux::page_size();
+}
+
+// Solaris allocates memory by pages.
+int os::vm_allocation_granularity() {
+ assert(os::Linux::page_size() != -1, "must call os::init");
+ return os::Linux::page_size();
+}
+
+// Rationale behind this function:
+// current (Mon Apr 25 20:12:18 MSD 2005) oprofile drops samples without executable
+// mapping for address (see lookup_dcookie() in the kernel module), thus we cannot get
+// samples for JITted code. Here we create private executable mapping over the code cache
+// and then we can use standard (well, almost, as mapping can change) way to provide
+// info for the reporting script by storing timestamp and location of symbol
+void linux_wrap_code(char* base, size_t size) {
+ static volatile jint cnt = 0;
+
+ if (!UseOprofile) {
+ return;
+ }
+
+ char buf[40];
+ int num = Atomic::add(1, &cnt);
+
+ sprintf(buf, "/tmp/hs-vm-%d-%d", os::current_process_id(), num);
+ unlink(buf);
+
+ int fd = open(buf, O_CREAT | O_RDWR, S_IRWXU);
+
+ if (fd != -1) {
+ off_t rv = lseek(fd, size-2, SEEK_SET);
+ if (rv != (off_t)-1) {
+ if (write(fd, "", 1) == 1) {
+ mmap(base, size,
+ PROT_READ|PROT_WRITE|PROT_EXEC,
+ MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE, fd, 0);
+ }
+ }
+ close(fd);
+ unlink(buf);
+ }
+}
+
+// NOTE: Linux kernel does not really reserve the pages for us.
+// All it does is to check if there are enough free pages
+// left at the time of mmap(). This could be a potential
+// problem.
+bool os::commit_memory(char* addr, size_t size) {
+ uintptr_t res = (uintptr_t) ::mmap(addr, size,
+ PROT_READ|PROT_WRITE|PROT_EXEC,
+ MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
+ return res != (uintptr_t) MAP_FAILED;
+}
+
+bool os::commit_memory(char* addr, size_t size, size_t alignment_hint) {
+ return commit_memory(addr, size);
+}
+
+void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) { }
+void os::free_memory(char *addr, size_t bytes) { }
+void os::numa_make_global(char *addr, size_t bytes) { }
+void os::numa_make_local(char *addr, size_t bytes) { }
+bool os::numa_topology_changed() { return false; }
+size_t os::numa_get_groups_num() { return 1; }
+int os::numa_get_group_id() { return 0; }
+size_t os::numa_get_leaf_groups(int *ids, size_t size) {
+ if (size > 0) {
+ ids[0] = 0;
+ return 1;
+ }
+ return 0;
+}
+
+bool os::get_page_info(char *start, page_info* info) {
+ return false;
+}
+
+char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
+ return end;
+}
+
+bool os::uncommit_memory(char* addr, size_t size) {
+ return ::mmap(addr, size,
+ PROT_READ|PROT_WRITE|PROT_EXEC,
+ MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0)
+ != MAP_FAILED;
+}
+
+static address _highest_vm_reserved_address = NULL;
+
+// If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
+// at 'requested_addr'. If there are existing memory mappings at the same
+// location, however, they will be overwritten. If 'fixed' is false,
+// 'requested_addr' is only treated as a hint, the return value may or
+// may not start from the requested address. Unlike Linux mmap(), this
+// function returns NULL to indicate failure.
+static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
+ char * addr;
+ int flags;
+
+ flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
+ if (fixed) {
+ assert((uintptr_t)requested_addr % os::Linux::page_size() == 0, "unaligned address");
+ flags |= MAP_FIXED;
+ }
+
+ addr = (char*)::mmap(requested_addr, bytes, PROT_READ|PROT_WRITE|PROT_EXEC,
+ flags, -1, 0);
+
+ if (addr != MAP_FAILED) {
+ // anon_mmap() should only get called during VM initialization,
+ // don't need lock (actually we can skip locking even it can be called
+ // from multiple threads, because _highest_vm_reserved_address is just a
+ // hint about the upper limit of non-stack memory regions.)
+ if ((address)addr + bytes > _highest_vm_reserved_address) {
+ _highest_vm_reserved_address = (address)addr + bytes;
+ }
+ }
+
+ return addr == MAP_FAILED ? NULL : addr;
+}
+
+// Don't update _highest_vm_reserved_address, because there might be memory
+// regions above addr + size. If so, releasing a memory region only creates
+// a hole in the address space, it doesn't help prevent heap-stack collision.
+//
+static int anon_munmap(char * addr, size_t size) {
+ return ::munmap(addr, size) == 0;
+}
+
+char* os::reserve_memory(size_t bytes, char* requested_addr,
+ size_t alignment_hint) {
+ return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
+}
+
+bool os::release_memory(char* addr, size_t size) {
+ return anon_munmap(addr, size);
+}
+
+static address highest_vm_reserved_address() {
+ return _highest_vm_reserved_address;
+}
+
+static bool linux_mprotect(char* addr, size_t size, int prot) {
+ // Linux wants the mprotect address argument to be page aligned.
+ char* bottom = (char*)align_size_down((intptr_t)addr, os::Linux::page_size());
+
+ // According to SUSv3, mprotect() should only be used with mappings
+ // established by mmap(), and mmap() always maps whole pages. Unaligned
+ // 'addr' likely indicates problem in the VM (e.g. trying to change
+ // protection of malloc'ed or statically allocated memory). Check the
+ // caller if you hit this assert.
+ assert(addr == bottom, "sanity check");
+
+ size = align_size_up(pointer_delta(addr, bottom, 1) + size, os::Linux::page_size());
+ return ::mprotect(bottom, size, prot) == 0;
+}
+
+bool os::protect_memory(char* addr, size_t size) {
+ return linux_mprotect(addr, size, PROT_READ);
+}
+
+bool os::guard_memory(char* addr, size_t size) {
+ return linux_mprotect(addr, size, PROT_NONE);
+}
+
+bool os::unguard_memory(char* addr, size_t size) {
+ return linux_mprotect(addr, size, PROT_READ|PROT_WRITE|PROT_EXEC);
+}
+
+// Large page support
+
+static size_t _large_page_size = 0;
+
+bool os::large_page_init() {
+ if (!UseLargePages) return false;
+
+ if (LargePageSizeInBytes) {
+ _large_page_size = LargePageSizeInBytes;
+ } else {
+ // large_page_size on Linux is used to round up heap size. x86 uses either
+ // 2M or 4M page, depending on whether PAE (Physical Address Extensions)
+ // mode is enabled. AMD64/EM64T uses 2M page in 64bit mode. IA64 can use
+ // page as large as 256M.
+ //
+ // Here we try to figure out page size by parsing /proc/meminfo and looking
+ // for a line with the following format:
+ // Hugepagesize: 2048 kB
+ //
+ // If we can't determine the value (e.g. /proc is not mounted, or the text
+ // format has been changed), we'll use the largest page size supported by
+ // the processor.
+
+ _large_page_size = IA32_ONLY(4 * M) AMD64_ONLY(2 * M) IA64_ONLY(256 * M) SPARC_ONLY(4 * M);
+
+ FILE *fp = fopen("/proc/meminfo", "r");
+ if (fp) {
+ while (!feof(fp)) {
+ int x = 0;
+ char buf[16];
+ if (fscanf(fp, "Hugepagesize: %d", &x) == 1) {
+ if (x && fgets(buf, sizeof(buf), fp) && strcmp(buf, " kB\n") == 0) {
+ _large_page_size = x * K;
+ break;
+ }
+ } else {
+ // skip to next line
+ for (;;) {
+ int ch = fgetc(fp);
+ if (ch == EOF || ch == (int)'\n') break;
+ }
+ }
+ }
+ fclose(fp);
+ }
+ }
+
+ const size_t default_page_size = (size_t)Linux::page_size();
+ if (_large_page_size > default_page_size) {
+ _page_sizes[0] = _large_page_size;
+ _page_sizes[1] = default_page_size;
+ _page_sizes[2] = 0;
+ }
+
+ // Large page support is available on 2.6 or newer kernel, some vendors
+ // (e.g. Redhat) have backported it to their 2.4 based distributions.
+ // We optimistically assume the support is available. If later it turns out
+ // not true, VM will automatically switch to use regular page size.
+ return true;
+}
+
+#ifndef SHM_HUGETLB
+#define SHM_HUGETLB 04000
+#endif
+
+char* os::reserve_memory_special(size_t bytes) {
+ assert(UseLargePages, "only for large pages");
+
+ key_t key = IPC_PRIVATE;
+ char *addr;
+
+ bool warn_on_failure = UseLargePages &&
+ (!FLAG_IS_DEFAULT(UseLargePages) ||
+ !FLAG_IS_DEFAULT(LargePageSizeInBytes)
+ );
+ char msg[128];
+
+ // Create a large shared memory region to attach to based on size.
+ // Currently, size is the total size of the heap
+ int shmid = shmget(key, bytes, SHM_HUGETLB|IPC_CREAT|SHM_R|SHM_W);
+ if (shmid == -1) {
+ // Possible reasons for shmget failure:
+ // 1. shmmax is too small for Java heap.
+ // > check shmmax value: cat /proc/sys/kernel/shmmax
+ // > increase shmmax value: echo "0xffffffff" > /proc/sys/kernel/shmmax
+ // 2. not enough large page memory.
+ // > check available large pages: cat /proc/meminfo
+ // > increase amount of large pages:
+ // echo new_value > /proc/sys/vm/nr_hugepages
+ // Note 1: different Linux may use different name for this property,
+ // e.g. on Redhat AS-3 it is "hugetlb_pool".
+ // Note 2: it's possible there's enough physical memory available but
+ // they are so fragmented after a long run that they can't
+ // coalesce into large pages. Try to reserve large pages when
+ // the system is still "fresh".
+ if (warn_on_failure) {
+ jio_snprintf(msg, sizeof(msg), "Failed to reserve shared memory (errno = %d).", errno);
+ warning(msg);
+ }
+ return NULL;
+ }
+
+ // attach to the region
+ addr = (char*)shmat(shmid, NULL, 0);
+ int err = errno;
+
+ // Remove shmid. If shmat() is successful, the actual shared memory segment
+ // will be deleted when it's detached by shmdt() or when the process
+ // terminates. If shmat() is not successful this will remove the shared
+ // segment immediately.
+ shmctl(shmid, IPC_RMID, NULL);
+
+ if ((intptr_t)addr == -1) {
+ if (warn_on_failure) {
+ jio_snprintf(msg, sizeof(msg), "Failed to attach shared memory (errno = %d).", err);
+ warning(msg);
+ }
+ return NULL;
+ }
+
+ return addr;
+}
+
+bool os::release_memory_special(char* base, size_t bytes) {
+ // detaching the SHM segment will also delete it, see reserve_memory_special()
+ int rslt = shmdt(base);
+ return rslt == 0;
+}
+
+size_t os::large_page_size() {
+ return _large_page_size;
+}
+
+// Linux does not support anonymous mmap with large page memory. The only way
+// to reserve large page memory without file backing is through SysV shared
+// memory API. The entire memory region is committed and pinned upfront.
+// Hopefully this will change in the future...
+bool os::can_commit_large_page_memory() {
+ return false;
+}
+
+// Reserve memory at an arbitrary address, only if that area is
+// available (and not reserved for something else).
+
+char* os::attempt_reserve_memory_at(size_t bytes, char* requested_addr) {
+ const int max_tries = 10;
+ char* base[max_tries];
+ size_t size[max_tries];
+ const size_t gap = 0x000000;
+
+ // Assert only that the size is a multiple of the page size, since
+ // that's all that mmap requires, and since that's all we really know
+ // about at this low abstraction level. If we need higher alignment,
+ // we can either pass an alignment to this method or verify alignment
+ // in one of the methods further up the call chain. See bug 5044738.
+ assert(bytes % os::vm_page_size() == 0, "reserving unexpected size block");
+
+ // Repeatedly allocate blocks until the block is allocated at the
+ // right spot. Give up after max_tries. Note that reserve_memory() will
+ // automatically update _highest_vm_reserved_address if the call is
+ // successful. The variable tracks the highest memory address every reserved
+ // by JVM. It is used to detect heap-stack collision if running with
+ // fixed-stack LinuxThreads. Because here we may attempt to reserve more
+ // space than needed, it could confuse the collision detecting code. To
+ // solve the problem, save current _highest_vm_reserved_address and
+ // calculate the correct value before return.
+ address old_highest = _highest_vm_reserved_address;
+
+ // Linux mmap allows caller to pass an address as hint; give it a try first,
+ // if kernel honors the hint then we can return immediately.
+ char * addr = anon_mmap(requested_addr, bytes, false);
+ if (addr == requested_addr) {
+ return requested_addr;
+ }
+
+ if (addr != NULL) {
+ // mmap() is successful but it fails to reserve at the requested address
+ anon_munmap(addr, bytes);
+ }
+
+ int i;
+ for (i = 0; i < max_tries; ++i) {
+ base[i] = reserve_memory(bytes);
+
+ if (base[i] != NULL) {
+ // Is this the block we wanted?
+ if (base[i] == requested_addr) {
+ size[i] = bytes;
+ break;
+ }
+
+ // Does this overlap the block we wanted? Give back the overlapped
+ // parts and try again.
+
+ size_t top_overlap = requested_addr + (bytes + gap) - base[i];
+ if (top_overlap >= 0 && top_overlap < bytes) {
+ unmap_memory(base[i], top_overlap);
+ base[i] += top_overlap;
+ size[i] = bytes - top_overlap;
+ } else {
+ size_t bottom_overlap = base[i] + bytes - requested_addr;
+ if (bottom_overlap >= 0 && bottom_overlap < bytes) {
+ unmap_memory(requested_addr, bottom_overlap);
+ size[i] = bytes - bottom_overlap;
+ } else {
+ size[i] = bytes;
+ }
+ }
+ }
+ }
+
+ // Give back the unused reserved pieces.
+
+ for (int j = 0; j < i; ++j) {
+ if (base[j] != NULL) {
+ unmap_memory(base[j], size[j]);
+ }
+ }
+
+ if (i < max_tries) {
+ _highest_vm_reserved_address = MAX2(old_highest, (address)requested_addr + bytes);
+ return requested_addr;
+ } else {
+ _highest_vm_reserved_address = old_highest;
+ return NULL;
+ }
+}
+
+size_t os::read(int fd, void *buf, unsigned int nBytes) {
+ return ::read(fd, buf, nBytes);
+}
+
+// TODO-FIXME: reconcile Solaris' os::sleep with the linux variation.
+// Solaris uses poll(), linux uses park().
+// Poll() is likely a better choice, assuming that Thread.interrupt()
+// generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
+// SIGSEGV, see 4355769.
+
+const int NANOSECS_PER_MILLISECS = 1000000;
+
+int os::sleep(Thread* thread, jlong millis, bool interruptible) {
+ assert(thread == Thread::current(), "thread consistency check");
+
+ ParkEvent * const slp = thread->_SleepEvent ;
+ slp->reset() ;
+ OrderAccess::fence() ;
+
+ if (interruptible) {
+ jlong prevtime = javaTimeNanos();
+
+ for (;;) {
+ if (os::is_interrupted(thread, true)) {
+ return OS_INTRPT;
+ }
+
+ jlong newtime = javaTimeNanos();
+
+ if (newtime - prevtime < 0) {
+ // time moving backwards, should only happen if no monotonic clock
+ // not a guarantee() because JVM should not abort on kernel/glibc bugs
+ assert(!Linux::supports_monotonic_clock(), "time moving backwards");
+ } else {
+ millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
+ }
+
+ if(millis <= 0) {
+ return OS_OK;
+ }
+
+ prevtime = newtime;
+
+ {
+ assert(thread->is_Java_thread(), "sanity check");
+ JavaThread *jt = (JavaThread *) thread;
+ ThreadBlockInVM tbivm(jt);
+ OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
+
+ jt->set_suspend_equivalent();
+ // cleared by handle_special_suspend_equivalent_condition() or
+ // java_suspend_self() via check_and_wait_while_suspended()
+
+ slp->park(millis);
+
+ // were we externally suspended while we were waiting?
+ jt->check_and_wait_while_suspended();
+ }
+ }
+ } else {
+ OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
+ jlong prevtime = javaTimeNanos();
+
+ for (;;) {
+ // It'd be nice to avoid the back-to-back javaTimeNanos() calls on
+ // the 1st iteration ...
+ jlong newtime = javaTimeNanos();
+
+ if (newtime - prevtime < 0) {
+ // time moving backwards, should only happen if no monotonic clock
+ // not a guarantee() because JVM should not abort on kernel/glibc bugs
+ assert(!Linux::supports_monotonic_clock(), "time moving backwards");
+ } else {
+ millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
+ }
+
+ if(millis <= 0) break ;
+
+ prevtime = newtime;
+ slp->park(millis);
+ }
+ return OS_OK ;
+ }
+}
+
+int os::naked_sleep() {
+ // %% make the sleep time an integer flag. for now use 1 millisec.
+ return os::sleep(Thread::current(), 1, false);
+}
+
+// Sleep forever; naked call to OS-specific sleep; use with CAUTION
+void os::infinite_sleep() {
+ while (true) { // sleep forever ...
+ ::sleep(100); // ... 100 seconds at a time
+ }
+}
+
+// Used to convert frequent JVM_Yield() to nops
+bool os::dont_yield() {
+ return DontYieldALot;
+}
+
+void os::yield() {
+ sched_yield();
+}
+
+os::YieldResult os::NakedYield() { sched_yield(); return os::YIELD_UNKNOWN ;}
+
+void os::yield_all(int attempts) {
+ // Yields to all threads, including threads with lower priorities
+ // Threads on Linux are all with same priority. The Solaris style
+ // os::yield_all() with nanosleep(1ms) is not necessary.
+ sched_yield();
+}
+
+// Called from the tight loops to possibly influence time-sharing heuristics
+void os::loop_breaker(int attempts) {
+ os::yield_all(attempts);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// thread priority support
+
+// Note: Normal Linux applications are run with SCHED_OTHER policy. SCHED_OTHER
+// only supports dynamic priority, static priority must be zero. For real-time
+// applications, Linux supports SCHED_RR which allows static priority (1-99).
+// However, for large multi-threaded applications, SCHED_RR is not only slower
+// than SCHED_OTHER, but also very unstable (my volano tests hang hard 4 out
+// of 5 runs - Sep 2005).
+//
+// The following code actually changes the niceness of kernel-thread/LWP. It
+// has an assumption that setpriority() only modifies one kernel-thread/LWP,
+// not the entire user process, and user level threads are 1:1 mapped to kernel
+// threads. It has always been the case, but could change in the future. For
+// this reason, the code should not be used as default (ThreadPriorityPolicy=0).
+// It is only used when ThreadPriorityPolicy=1 and requires root privilege.
+
+int os::java_to_os_priority[MaxPriority + 1] = {
+ 19, // 0 Entry should never be used
+
+ 4, // 1 MinPriority
+ 3, // 2
+ 2, // 3
+
+ 1, // 4
+ 0, // 5 NormPriority
+ -1, // 6
+
+ -2, // 7
+ -3, // 8
+ -4, // 9 NearMaxPriority
+
+ -5 // 10 MaxPriority
+};
+
+static int prio_init() {
+ if (ThreadPriorityPolicy == 1) {
+ // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
+ // if effective uid is not root. Perhaps, a more elegant way of doing
+ // this is to test CAP_SYS_NICE capability, but that will require libcap.so
+ if (geteuid() != 0) {
+ if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
+ warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
+ }
+ ThreadPriorityPolicy = 0;
+ }
+ }
+ return 0;
+}
+
+OSReturn os::set_native_priority(Thread* thread, int newpri) {
+ if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) return OS_OK;
+
+ int ret = setpriority(PRIO_PROCESS, thread->osthread()->thread_id(), newpri);
+ return (ret == 0) ? OS_OK : OS_ERR;
+}
+
+OSReturn os::get_native_priority(const Thread* const thread, int *priority_ptr) {
+ if ( !UseThreadPriorities || ThreadPriorityPolicy == 0 ) {
+ *priority_ptr = java_to_os_priority[NormPriority];
+ return OS_OK;
+ }
+
+ errno = 0;
+ *priority_ptr = getpriority(PRIO_PROCESS, thread->osthread()->thread_id());
+ return (*priority_ptr != -1 || errno == 0 ? OS_OK : OS_ERR);
+}
+
+// Hint to the underlying OS that a task switch would not be good.
+// Void return because it's a hint and can fail.
+void os::hint_no_preempt() {}
+
+////////////////////////////////////////////////////////////////////////////////
+// suspend/resume support
+
+// the low-level signal-based suspend/resume support is a remnant from the
+// old VM-suspension that used to be for java-suspension, safepoints etc,
+// within hotspot. Now there is a single use-case for this:
+// - calling get_thread_pc() on the VMThread by the flat-profiler task
+// that runs in the watcher thread.
+// The remaining code is greatly simplified from the more general suspension
+// code that used to be used.
+//
+// The protocol is quite simple:
+// - suspend:
+// - sends a signal to the target thread
+// - polls the suspend state of the osthread using a yield loop
+// - target thread signal handler (SR_handler) sets suspend state
+// and blocks in sigsuspend until continued
+// - resume:
+// - sets target osthread state to continue
+// - sends signal to end the sigsuspend loop in the SR_handler
+//
+// Note that the SR_lock plays no role in this suspend/resume protocol.
+//
+
+static void resume_clear_context(OSThread *osthread) {
+ osthread->set_ucontext(NULL);
+ osthread->set_siginfo(NULL);
+
+ // notify the suspend action is completed, we have now resumed
+ osthread->sr.clear_suspended();
+}
+
+static void suspend_save_context(OSThread *osthread, siginfo_t* siginfo, ucontext_t* context) {
+ osthread->set_ucontext(context);
+ osthread->set_siginfo(siginfo);
+}
+
+//
+// Handler function invoked when a thread's execution is suspended or
+// resumed. We have to be careful that only async-safe functions are
+// called here (Note: most pthread functions are not async safe and
+// should be avoided.)
+//
+// Note: sigwait() is a more natural fit than sigsuspend() from an
+// interface point of view, but sigwait() prevents the signal hander
+// from being run. libpthread would get very confused by not having
+// its signal handlers run and prevents sigwait()'s use with the
+// mutex granting granting signal.
+//
+// Currently only ever called on the VMThread
+//
+static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
+ // Save and restore errno to avoid confusing native code with EINTR
+ // after sigsuspend.
+ int old_errno = errno;
+
+ Thread* thread = Thread::current();
+ OSThread* osthread = thread->osthread();
+ assert(thread->is_VM_thread(), "Must be VMThread");
+ // read current suspend action
+ int action = osthread->sr.suspend_action();
+ if (action == SR_SUSPEND) {
+ suspend_save_context(osthread, siginfo, context);
+
+ // Notify the suspend action is about to be completed. do_suspend()
+ // waits until SR_SUSPENDED is set and then returns. We will wait
+ // here for a resume signal and that completes the suspend-other
+ // action. do_suspend/do_resume is always called as a pair from
+ // the same thread - so there are no races
+
+ // notify the caller
+ osthread->sr.set_suspended();
+
+ sigset_t suspend_set; // signals for sigsuspend()
+
+ // get current set of blocked signals and unblock resume signal
+ pthread_sigmask(SIG_BLOCK, NULL, &suspend_set);
+ sigdelset(&suspend_set, SR_signum);
+
+ // wait here until we are resumed
+ do {
+ sigsuspend(&suspend_set);
+ // ignore all returns until we get a resume signal
+ } while (osthread->sr.suspend_action() != SR_CONTINUE);
+
+ resume_clear_context(osthread);
+
+ } else {
+ assert(action == SR_CONTINUE, "unexpected sr action");
+ // nothing special to do - just leave the handler
+ }
+
+ errno = old_errno;
+}
+
+
+static int SR_initialize() {
+ struct sigaction act;
+ char *s;
+ /* Get signal number to use for suspend/resume */
+ if ((s = ::getenv("_JAVA_SR_SIGNUM")) != 0) {
+ int sig = ::strtol(s, 0, 10);
+ if (sig > 0 || sig < _NSIG) {
+ SR_signum = sig;
+ }
+ }
+
+ assert(SR_signum > SIGSEGV && SR_signum > SIGBUS,
+ "SR_signum must be greater than max(SIGSEGV, SIGBUS), see 4355769");
+
+ sigemptyset(&SR_sigset);
+ sigaddset(&SR_sigset, SR_signum);
+
+ /* Set up signal handler for suspend/resume */
+ act.sa_flags = SA_RESTART|SA_SIGINFO;
+ act.sa_handler = (void (*)(int)) SR_handler;
+
+ // SR_signum is blocked by default.
+ // 4528190 - We also need to block pthread restart signal (32 on all
+ // supported Linux platforms). Note that LinuxThreads need to block
+ // this signal for all threads to work properly. So we don't have
+ // to use hard-coded signal number when setting up the mask.
+ pthread_sigmask(SIG_BLOCK, NULL, &act.sa_mask);
+
+ if (sigaction(SR_signum, &act, 0) == -1) {
+ return -1;
+ }
+
+ // Save signal flag
+ os::Linux::set_our_sigflags(SR_signum, act.sa_flags);
+ return 0;
+}
+
+static int SR_finalize() {
+ return 0;
+}
+
+
+// returns true on success and false on error - really an error is fatal
+// but this seems the normal response to library errors
+static bool do_suspend(OSThread* osthread) {
+ // mark as suspended and send signal
+ osthread->sr.set_suspend_action(SR_SUSPEND);
+ int status = pthread_kill(osthread->pthread_id(), SR_signum);
+ assert_status(status == 0, status, "pthread_kill");
+
+ // check status and wait until notified of suspension
+ if (status == 0) {
+ for (int i = 0; !osthread->sr.is_suspended(); i++) {
+ os::yield_all(i);
+ }
+ osthread->sr.set_suspend_action(SR_NONE);
+ return true;
+ }
+ else {
+ osthread->sr.set_suspend_action(SR_NONE);
+ return false;
+ }
+}
+
+static void do_resume(OSThread* osthread) {
+ assert(osthread->sr.is_suspended(), "thread should be suspended");
+ osthread->sr.set_suspend_action(SR_CONTINUE);
+
+ int status = pthread_kill(osthread->pthread_id(), SR_signum);
+ assert_status(status == 0, status, "pthread_kill");
+ // check status and wait unit notified of resumption
+ if (status == 0) {
+ for (int i = 0; osthread->sr.is_suspended(); i++) {
+ os::yield_all(i);
+ }
+ }
+ osthread->sr.set_suspend_action(SR_NONE);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// interrupt support
+
+void os::interrupt(Thread* thread) {
+ assert(Thread::current() == thread || Threads_lock->owned_by_self(),
+ "possibility of dangling Thread pointer");
+
+ OSThread* osthread = thread->osthread();
+
+ if (!osthread->interrupted()) {
+ osthread->set_interrupted(true);
+ // More than one thread can get here with the same value of osthread,
+ // resulting in multiple notifications. We do, however, want the store
+ // to interrupted() to be visible to other threads before we execute unpark().
+ OrderAccess::fence();
+ ParkEvent * const slp = thread->_SleepEvent ;
+ if (slp != NULL) slp->unpark() ;
+ }
+
+ // For JSR166. Unpark even if interrupt status already was set
+ if (thread->is_Java_thread())
+ ((JavaThread*)thread)->parker()->unpark();
+
+ ParkEvent * ev = thread->_ParkEvent ;
+ if (ev != NULL) ev->unpark() ;
+
+}
+
+bool os::is_interrupted(Thread* thread, bool clear_interrupted) {
+ assert(Thread::current() == thread || Threads_lock->owned_by_self(),
+ "possibility of dangling Thread pointer");
+
+ OSThread* osthread = thread->osthread();
+
+ bool interrupted = osthread->interrupted();
+
+ if (interrupted && clear_interrupted) {
+ osthread->set_interrupted(false);
+ // consider thread->_SleepEvent->reset() ... optional optimization
+ }
+
+ return interrupted;
+}
+
+///////////////////////////////////////////////////////////////////////////////////
+// signal handling (except suspend/resume)
+
+// This routine may be used by user applications as a "hook" to catch signals.
+// The user-defined signal handler must pass unrecognized signals to this
+// routine, and if it returns true (non-zero), then the signal handler must
+// return immediately. If the flag "abort_if_unrecognized" is true, then this
+// routine will never retun false (zero), but instead will execute a VM panic
+// routine kill the process.
+//
+// If this routine returns false, it is OK to call it again. This allows
+// the user-defined signal handler to perform checks either before or after
+// the VM performs its own checks. Naturally, the user code would be making
+// a serious error if it tried to handle an exception (such as a null check
+// or breakpoint) that the VM was generating for its own correct operation.
+//
+// This routine may recognize any of the following kinds of signals:
+// SIGBUS, SIGSEGV, SIGILL, SIGFPE, SIGQUIT, SIGPIPE, SIGXFSZ, SIGUSR1.
+// It should be consulted by handlers for any of those signals.
+//
+// The caller of this routine must pass in the three arguments supplied
+// to the function referred to in the "sa_sigaction" (not the "sa_handler")
+// field of the structure passed to sigaction(). This routine assumes that
+// the sa_flags field passed to sigaction() includes SA_SIGINFO and SA_RESTART.
+//
+// Note that the VM will print warnings if it detects conflicting signal
+// handlers, unless invoked with the option "-XX:+AllowUserSignalHandlers".
+//
+extern "C" int
+JVM_handle_linux_signal(int signo, siginfo_t* siginfo,
+ void* ucontext, int abort_if_unrecognized);
+
+void signalHandler(int sig, siginfo_t* info, void* uc) {
+ assert(info != NULL && uc != NULL, "it must be old kernel");
+ JVM_handle_linux_signal(sig, info, uc, true);
+}
+
+
+// This boolean allows users to forward their own non-matching signals
+// to JVM_handle_linux_signal, harmlessly.
+bool os::Linux::signal_handlers_are_installed = false;
+
+// For signal-chaining
+struct sigaction os::Linux::sigact[MAXSIGNUM];
+unsigned int os::Linux::sigs = 0;
+bool os::Linux::libjsig_is_loaded = false;
+typedef struct sigaction *(*get_signal_t)(int);
+get_signal_t os::Linux::get_signal_action = NULL;
+
+struct sigaction* os::Linux::get_chained_signal_action(int sig) {
+ struct sigaction *actp = NULL;
+
+ if (libjsig_is_loaded) {
+ // Retrieve the old signal handler from libjsig
+ actp = (*get_signal_action)(sig);
+ }
+ if (actp == NULL) {
+ // Retrieve the preinstalled signal handler from jvm
+ actp = get_preinstalled_handler(sig);
+ }
+
+ return actp;
+}
+
+static bool call_chained_handler(struct sigaction *actp, int sig,
+ siginfo_t *siginfo, void *context) {
+ // Call the old signal handler
+ if (actp->sa_handler == SIG_DFL) {
+ // It's more reasonable to let jvm treat it as an unexpected exception
+ // instead of taking the default action.
+ return false;
+ } else if (actp->sa_handler != SIG_IGN) {
+ if ((actp->sa_flags & SA_NODEFER) == 0) {
+ // automaticlly block the signal
+ sigaddset(&(actp->sa_mask), sig);
+ }
+
+ sa_handler_t hand;
+ sa_sigaction_t sa;
+ bool siginfo_flag_set = (actp->sa_flags & SA_SIGINFO) != 0;
+ // retrieve the chained handler
+ if (siginfo_flag_set) {
+ sa = actp->sa_sigaction;
+ } else {
+ hand = actp->sa_handler;
+ }
+
+ if ((actp->sa_flags & SA_RESETHAND) != 0) {
+ actp->sa_handler = SIG_DFL;
+ }
+
+ // try to honor the signal mask
+ sigset_t oset;
+ pthread_sigmask(SIG_SETMASK, &(actp->sa_mask), &oset);
+
+ // call into the chained handler
+ if (siginfo_flag_set) {
+ (*sa)(sig, siginfo, context);
+ } else {
+ (*hand)(sig);
+ }
+
+ // restore the signal mask
+ pthread_sigmask(SIG_SETMASK, &oset, 0);
+ }
+ // Tell jvm's signal handler the signal is taken care of.
+ return true;
+}
+
+bool os::Linux::chained_handler(int sig, siginfo_t* siginfo, void* context) {
+ bool chained = false;
+ // signal-chaining
+ if (UseSignalChaining) {
+ struct sigaction *actp = get_chained_signal_action(sig);
+ if (actp != NULL) {
+ chained = call_chained_handler(actp, sig, siginfo, context);
+ }
+ }
+ return chained;
+}
+
+struct sigaction* os::Linux::get_preinstalled_handler(int sig) {
+ if ((( (unsigned int)1 << sig ) & sigs) != 0) {
+ return &sigact[sig];
+ }
+ return NULL;
+}
+
+void os::Linux::save_preinstalled_handler(int sig, struct sigaction& oldAct) {
+ assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
+ sigact[sig] = oldAct;
+ sigs |= (unsigned int)1 << sig;
+}
+
+// for diagnostic
+int os::Linux::sigflags[MAXSIGNUM];
+
+int os::Linux::get_our_sigflags(int sig) {
+ assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
+ return sigflags[sig];
+}
+
+void os::Linux::set_our_sigflags(int sig, int flags) {
+ assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
+ sigflags[sig] = flags;
+}
+
+void os::Linux::set_signal_handler(int sig, bool set_installed) {
+ // Check for overwrite.
+ struct sigaction oldAct;
+ sigaction(sig, (struct sigaction*)NULL, &oldAct);
+
+ void* oldhand = oldAct.sa_sigaction
+ ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
+ : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
+ if (oldhand != CAST_FROM_FN_PTR(void*, SIG_DFL) &&
+ oldhand != CAST_FROM_FN_PTR(void*, SIG_IGN) &&
+ oldhand != CAST_FROM_FN_PTR(void*, (sa_sigaction_t)signalHandler)) {
+ if (AllowUserSignalHandlers || !set_installed) {
+ // Do not overwrite; user takes responsibility to forward to us.
+ return;
+ } else if (UseSignalChaining) {
+ // save the old handler in jvm
+ save_preinstalled_handler(sig, oldAct);
+ // libjsig also interposes the sigaction() call below and saves the
+ // old sigaction on it own.
+ } else {
+ fatal2("Encountered unexpected pre-existing sigaction handler %#lx for signal %d.", (long)oldhand, sig);
+ }
+ }
+
+ struct sigaction sigAct;
+ sigfillset(&(sigAct.sa_mask));
+ sigAct.sa_handler = SIG_DFL;
+ if (!set_installed) {
+ sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
+ } else {
+ sigAct.sa_sigaction = signalHandler;
+ sigAct.sa_flags = SA_SIGINFO|SA_RESTART;
+ }
+ // Save flags, which are set by ours
+ assert(sig > 0 && sig < MAXSIGNUM, "vm signal out of expected range");
+ sigflags[sig] = sigAct.sa_flags;
+
+ int ret = sigaction(sig, &sigAct, &oldAct);
+ assert(ret == 0, "check");
+
+ void* oldhand2 = oldAct.sa_sigaction
+ ? CAST_FROM_FN_PTR(void*, oldAct.sa_sigaction)
+ : CAST_FROM_FN_PTR(void*, oldAct.sa_handler);
+ assert(oldhand2 == oldhand, "no concurrent signal handler installation");
+}
+
+// install signal handlers for signals that HotSpot needs to
+// handle in order to support Java-level exception handling.
+
+void os::Linux::install_signal_handlers() {
+ if (!signal_handlers_are_installed) {
+ signal_handlers_are_installed = true;
+
+ // signal-chaining
+ typedef void (*signal_setting_t)();
+ signal_setting_t begin_signal_setting = NULL;
+ signal_setting_t end_signal_setting = NULL;
+ begin_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
+ dlsym(RTLD_DEFAULT, "JVM_begin_signal_setting"));
+ if (begin_signal_setting != NULL) {
+ end_signal_setting = CAST_TO_FN_PTR(signal_setting_t,
+ dlsym(RTLD_DEFAULT, "JVM_end_signal_setting"));
+ get_signal_action = CAST_TO_FN_PTR(get_signal_t,
+ dlsym(RTLD_DEFAULT, "JVM_get_signal_action"));
+ libjsig_is_loaded = true;
+ assert(UseSignalChaining, "should enable signal-chaining");
+ }
+ if (libjsig_is_loaded) {
+ // Tell libjsig jvm is setting signal handlers
+ (*begin_signal_setting)();
+ }
+
+ set_signal_handler(SIGSEGV, true);
+ set_signal_handler(SIGPIPE, true);
+ set_signal_handler(SIGBUS, true);
+ set_signal_handler(SIGILL, true);
+ set_signal_handler(SIGFPE, true);
+ set_signal_handler(SIGXFSZ, true);
+
+ if (libjsig_is_loaded) {
+ // Tell libjsig jvm finishes setting signal handlers
+ (*end_signal_setting)();
+ }
+
+ // We don't activate signal checker if libjsig is in place, we trust ourselves
+ // and if UserSignalHandler is installed all bets are off
+ if (CheckJNICalls) {
+ if (libjsig_is_loaded) {
+ tty->print_cr("Info: libjsig is activated, all active signal checking is disabled");
+ check_signals = false;
+ }
+ if (AllowUserSignalHandlers) {
+ tty->print_cr("Info: AllowUserSignalHandlers is activated, all active signal checking is disabled");
+ check_signals = false;
+ }
+ }
+ }
+}
+
+// This is the fastest way to get thread cpu time on Linux.
+// Returns cpu time (user+sys) for any thread, not only for current.
+// POSIX compliant clocks are implemented in the kernels 2.6.16+.
+// It might work on 2.6.10+ with a special kernel/glibc patch.
+// For reference, please, see IEEE Std 1003.1-2004:
+// http://www.unix.org/single_unix_specification
+
+jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
+ struct timespec tp;
+ int rc = os::Linux::clock_gettime(clockid, &tp);
+ assert(rc == 0, "clock_gettime is expected to return 0 code");
+
+ return (tp.tv_sec * SEC_IN_NANOSECS) + tp.tv_nsec;
+}
+
+/////
+// glibc on Linux platform uses non-documented flag
+// to indicate, that some special sort of signal
+// trampoline is used.
+// We will never set this flag, and we should
+// ignore this flag in our diagnostic
+#ifdef SIGNIFICANT_SIGNAL_MASK
+#undef SIGNIFICANT_SIGNAL_MASK
+#endif
+#define SIGNIFICANT_SIGNAL_MASK (~0x04000000)
+
+static const char* get_signal_handler_name(address handler,
+ char* buf, int buflen) {
+ int offset;
+ bool found = os::dll_address_to_library_name(handler, buf, buflen, &offset);
+ if (found) {
+ // skip directory names
+ const char *p1, *p2;
+ p1 = buf;
+ size_t len = strlen(os::file_separator());
+ while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
+ jio_snprintf(buf, buflen, "%s+0x%x", p1, offset);
+ } else {
+ jio_snprintf(buf, buflen, PTR_FORMAT, handler);
+ }
+ return buf;
+}
+
+static void print_signal_handler(outputStream* st, int sig,
+ char* buf, size_t buflen) {
+ struct sigaction sa;
+
+ sigaction(sig, NULL, &sa);
+
+ // See comment for SIGNIFICANT_SIGNAL_MASK define
+ sa.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
+
+ st->print("%s: ", os::exception_name(sig, buf, buflen));
+
+ address handler = (sa.sa_flags & SA_SIGINFO)
+ ? CAST_FROM_FN_PTR(address, sa.sa_sigaction)
+ : CAST_FROM_FN_PTR(address, sa.sa_handler);
+
+ if (handler == CAST_FROM_FN_PTR(address, SIG_DFL)) {
+ st->print("SIG_DFL");
+ } else if (handler == CAST_FROM_FN_PTR(address, SIG_IGN)) {
+ st->print("SIG_IGN");
+ } else {
+ st->print("[%s]", get_signal_handler_name(handler, buf, buflen));
+ }
+
+ st->print(", sa_mask[0]=" PTR32_FORMAT, *(uint32_t*)&sa.sa_mask);
+
+ address rh = VMError::get_resetted_sighandler(sig);
+ // May be, handler was resetted by VMError?
+ if(rh != NULL) {
+ handler = rh;
+ sa.sa_flags = VMError::get_resetted_sigflags(sig) & SIGNIFICANT_SIGNAL_MASK;
+ }
+
+ st->print(", sa_flags=" PTR32_FORMAT, sa.sa_flags);
+
+ // Check: is it our handler?
+ if(handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler) ||
+ handler == CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler)) {
+ // It is our signal handler
+ // check for flags, reset system-used one!
+ if((int)sa.sa_flags != os::Linux::get_our_sigflags(sig)) {
+ st->print(
+ ", flags was changed from " PTR32_FORMAT ", consider using jsig library",
+ os::Linux::get_our_sigflags(sig));
+ }
+ }
+ st->cr();
+}
+
+
+#define DO_SIGNAL_CHECK(sig) \
+ if (!sigismember(&check_signal_done, sig)) \
+ os::Linux::check_signal_handler(sig)
+
+// This method is a periodic task to check for misbehaving JNI applications
+// under CheckJNI, we can add any periodic checks here
+
+void os::run_periodic_checks() {
+
+ if (check_signals == false) return;
+
+ // SEGV and BUS if overridden could potentially prevent
+ // generation of hs*.log in the event of a crash, debugging
+ // such a case can be very challenging, so we absolutely
+ // check the following for a good measure:
+ DO_SIGNAL_CHECK(SIGSEGV);
+ DO_SIGNAL_CHECK(SIGILL);
+ DO_SIGNAL_CHECK(SIGFPE);
+ DO_SIGNAL_CHECK(SIGBUS);
+ DO_SIGNAL_CHECK(SIGPIPE);
+ DO_SIGNAL_CHECK(SIGXFSZ);
+
+
+ // ReduceSignalUsage allows the user to override these handlers
+ // see comments at the very top and jvm_solaris.h
+ if (!ReduceSignalUsage) {
+ DO_SIGNAL_CHECK(SHUTDOWN1_SIGNAL);
+ DO_SIGNAL_CHECK(SHUTDOWN2_SIGNAL);
+ DO_SIGNAL_CHECK(SHUTDOWN3_SIGNAL);
+ DO_SIGNAL_CHECK(BREAK_SIGNAL);
+ }
+
+ DO_SIGNAL_CHECK(SR_signum);
+ DO_SIGNAL_CHECK(INTERRUPT_SIGNAL);
+}
+
+typedef int (*os_sigaction_t)(int, const struct sigaction *, struct sigaction *);
+
+static os_sigaction_t os_sigaction = NULL;
+
+void os::Linux::check_signal_handler(int sig) {
+ char buf[O_BUFLEN];
+ address jvmHandler = NULL;
+
+
+ struct sigaction act;
+ if (os_sigaction == NULL) {
+ // only trust the default sigaction, in case it has been interposed
+ os_sigaction = (os_sigaction_t)dlsym(RTLD_DEFAULT, "sigaction");
+ if (os_sigaction == NULL) return;
+ }
+
+ os_sigaction(sig, (struct sigaction*)NULL, &act);
+
+
+ act.sa_flags &= SIGNIFICANT_SIGNAL_MASK;
+
+ address thisHandler = (act.sa_flags & SA_SIGINFO)
+ ? CAST_FROM_FN_PTR(address, act.sa_sigaction)
+ : CAST_FROM_FN_PTR(address, act.sa_handler) ;
+
+
+ switch(sig) {
+ case SIGSEGV:
+ case SIGBUS:
+ case SIGFPE:
+ case SIGPIPE:
+ case SIGILL:
+ case SIGXFSZ:
+ jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)signalHandler);
+ break;
+
+ case SHUTDOWN1_SIGNAL:
+ case SHUTDOWN2_SIGNAL:
+ case SHUTDOWN3_SIGNAL:
+ case BREAK_SIGNAL:
+ jvmHandler = (address)user_handler();
+ break;
+
+ case INTERRUPT_SIGNAL:
+ jvmHandler = CAST_FROM_FN_PTR(address, SIG_DFL);
+ break;
+
+ default:
+ if (sig == SR_signum) {
+ jvmHandler = CAST_FROM_FN_PTR(address, (sa_sigaction_t)SR_handler);
+ } else {
+ return;
+ }
+ break;
+ }
+
+ if (thisHandler != jvmHandler) {
+ tty->print("Warning: %s handler ", exception_name(sig, buf, O_BUFLEN));
+ tty->print("expected:%s", get_signal_handler_name(jvmHandler, buf, O_BUFLEN));
+ tty->print_cr(" found:%s", get_signal_handler_name(thisHandler, buf, O_BUFLEN));
+ // No need to check this sig any longer
+ sigaddset(&check_signal_done, sig);
+ } else if(os::Linux::get_our_sigflags(sig) != 0 && (int)act.sa_flags != os::Linux::get_our_sigflags(sig)) {
+ tty->print("Warning: %s handler flags ", exception_name(sig, buf, O_BUFLEN));
+ tty->print("expected:" PTR32_FORMAT, os::Linux::get_our_sigflags(sig));
+ tty->print_cr(" found:" PTR32_FORMAT, act.sa_flags);
+ // No need to check this sig any longer
+ sigaddset(&check_signal_done, sig);
+ }
+
+ // Dump all the signal
+ if (sigismember(&check_signal_done, sig)) {
+ print_signal_handlers(tty, buf, O_BUFLEN);
+ }
+}
+
+extern void report_error(char* file_name, int line_no, char* title, char* format, ...);
+
+extern bool signal_name(int signo, char* buf, size_t len);
+
+const char* os::exception_name(int exception_code, char* buf, size_t size) {
+ if (0 < exception_code && exception_code <= SIGRTMAX) {
+ // signal
+ if (!signal_name(exception_code, buf, size)) {
+ jio_snprintf(buf, size, "SIG%d", exception_code);
+ }
+ return buf;
+ } else {
+ return NULL;
+ }
+}
+
+// this is called _before_ the most of global arguments have been parsed
+void os::init(void) {
+ char dummy; /* used to get a guess on initial stack address */
+// first_hrtime = gethrtime();
+
+ // With LinuxThreads the JavaMain thread pid (primordial thread)
+ // is different than the pid of the java launcher thread.
+ // So, on Linux, the launcher thread pid is passed to the VM
+ // via the sun.java.launcher.pid property.
+ // Use this property instead of getpid() if it was correctly passed.
+ // See bug 6351349.
+ pid_t java_launcher_pid = (pid_t) Arguments::sun_java_launcher_pid();
+
+ _initial_pid = (java_launcher_pid > 0) ? java_launcher_pid : getpid();
+
+ clock_tics_per_sec = sysconf(_SC_CLK_TCK);
+
+ init_random(1234567);
+
+ ThreadCritical::initialize();
+
+ Linux::set_page_size(sysconf(_SC_PAGESIZE));
+ if (Linux::page_size() == -1) {
+ fatal1("os_linux.cpp: os::init: sysconf failed (%s)", strerror(errno));
+ }
+ init_page_sizes((size_t) Linux::page_size());
+
+ Linux::initialize_system_info();
+
+ // main_thread points to the aboriginal thread
+ Linux::_main_thread = pthread_self();
+
+ Linux::clock_init();
+ initial_time_count = os::elapsed_counter();
+}
+
+// To install functions for atexit system call
+extern "C" {
+ static void perfMemory_exit_helper() {
+ perfMemory_exit();
+ }
+}
+
+// this is called _after_ the global arguments have been parsed
+jint os::init_2(void)
+{
+ Linux::fast_thread_clock_init();
+
+ // Allocate a single page and mark it as readable for safepoint polling
+ address polling_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+ guarantee( polling_page != MAP_FAILED, "os::init_2: failed to allocate polling page" );
+
+ os::set_polling_page( polling_page );
+
+#ifndef PRODUCT
+ if(Verbose && PrintMiscellaneous)
+ tty->print("[SafePoint Polling address: " INTPTR_FORMAT "]\n", (intptr_t)polling_page);
+#endif
+
+ if (!UseMembar) {
+ address mem_serialize_page = (address) ::mmap(NULL, Linux::page_size(), PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+ guarantee( mem_serialize_page != NULL, "mmap Failed for memory serialize page");
+ os::set_memory_serialize_page( mem_serialize_page );
+
+#ifndef PRODUCT
+ if(Verbose && PrintMiscellaneous)
+ tty->print("[Memory Serialize Page address: " INTPTR_FORMAT "]\n", (intptr_t)mem_serialize_page);
+#endif
+ }
+
+ FLAG_SET_DEFAULT(UseLargePages, os::large_page_init());
+
+ // initialize suspend/resume support - must do this before signal_sets_init()
+ if (SR_initialize() != 0) {
+ perror("SR_initialize failed");
+ return JNI_ERR;
+ }
+
+ Linux::signal_sets_init();
+ Linux::install_signal_handlers();
+
+ size_t threadStackSizeInBytes = ThreadStackSize * K;
+ if (threadStackSizeInBytes != 0 &&
+ threadStackSizeInBytes < Linux::min_stack_allowed) {
+ tty->print_cr("\nThe stack size specified is too small, "
+ "Specify at least %dk",
+ Linux::min_stack_allowed / K);
+ return JNI_ERR;
+ }
+
+ // Make the stack size a multiple of the page size so that
+ // the yellow/red zones can be guarded.
+ JavaThread::set_stack_size_at_create(round_to(threadStackSizeInBytes,
+ vm_page_size()));
+
+ Linux::capture_initial_stack(JavaThread::stack_size_at_create());
+
+ Linux::libpthread_init();
+ if (PrintMiscellaneous && (Verbose || WizardMode)) {
+ tty->print_cr("[HotSpot is running with %s, %s(%s)]\n",
+ Linux::glibc_version(), Linux::libpthread_version(),
+ Linux::is_floating_stack() ? "floating stack" : "fixed stack");
+ }
+
+ if (MaxFDLimit) {
+ // set the number of file descriptors to max. print out error
+ // if getrlimit/setrlimit fails but continue regardless.
+ struct rlimit nbr_files;
+ int status = getrlimit(RLIMIT_NOFILE, &nbr_files);
+ if (status != 0) {
+ if (PrintMiscellaneous && (Verbose || WizardMode))
+ perror("os::init_2 getrlimit failed");
+ } else {
+ nbr_files.rlim_cur = nbr_files.rlim_max;
+ status = setrlimit(RLIMIT_NOFILE, &nbr_files);
+ if (status != 0) {
+ if (PrintMiscellaneous && (Verbose || WizardMode))
+ perror("os::init_2 setrlimit failed");
+ }
+ }
+ }
+
+ // Initialize lock used to serialize thread creation (see os::create_thread)
+ Linux::set_createThread_lock(new Mutex(Mutex::leaf, "createThread_lock", false));
+
+ // Initialize HPI.
+ jint hpi_result = hpi::initialize();
+ if (hpi_result != JNI_OK) {
+ tty->print_cr("There was an error trying to initialize the HPI library.");
+ return hpi_result;
+ }
+
+ // at-exit methods are called in the reverse order of their registration.
+ // atexit functions are called on return from main or as a result of a
+ // call to exit(3C). There can be only 32 of these functions registered
+ // and atexit() does not set errno.
+
+ if (PerfAllowAtExitRegistration) {
+ // only register atexit functions if PerfAllowAtExitRegistration is set.
+ // atexit functions can be delayed until process exit time, which
+ // can be problematic for embedded VM situations. Embedded VMs should
+ // call DestroyJavaVM() to assure that VM resources are released.
+
+ // note: perfMemory_exit_helper atexit function may be removed in
+ // the future if the appropriate cleanup code can be added to the
+ // VM_Exit VMOperation's doit method.
+ if (atexit(perfMemory_exit_helper) != 0) {
+ warning("os::init2 atexit(perfMemory_exit_helper) failed");
+ }
+ }
+
+ // initialize thread priority policy
+ prio_init();
+
+ return JNI_OK;
+}
+
+// Mark the polling page as unreadable
+void os::make_polling_page_unreadable(void) {
+ if( !guard_memory((char*)_polling_page, Linux::page_size()) )
+ fatal("Could not disable polling page");
+};
+
+// Mark the polling page as readable
+void os::make_polling_page_readable(void) {
+ if( !protect_memory((char *)_polling_page, Linux::page_size()) )
+ fatal("Could not enable polling page");
+};
+
+int os::active_processor_count() {
+ // Linux doesn't yet have a (official) notion of processor sets,
+ // so just return the number of online processors.
+ int online_cpus = ::sysconf(_SC_NPROCESSORS_ONLN);
+ assert(online_cpus > 0 && online_cpus <= processor_count(), "sanity check");
+ return online_cpus;
+}
+
+bool os::distribute_processes(uint length, uint* distribution) {
+ // Not yet implemented.
+ return false;
+}
+
+bool os::bind_to_processor(uint processor_id) {
+ // Not yet implemented.
+ return false;
+}
+
+///
+
+// Suspends the target using the signal mechanism and then grabs the PC before
+// resuming the target. Used by the flat-profiler only
+ExtendedPC os::get_thread_pc(Thread* thread) {
+ // Make sure that it is called by the watcher for the VMThread
+ assert(Thread::current()->is_Watcher_thread(), "Must be watcher");
+ assert(thread->is_VM_thread(), "Can only be called for VMThread");
+
+ ExtendedPC epc;
+
+ OSThread* osthread = thread->osthread();
+ if (do_suspend(osthread)) {
+ if (osthread->ucontext() != NULL) {
+ epc = os::Linux::ucontext_get_pc(osthread->ucontext());
+ } else {
+ // NULL context is unexpected, double-check this is the VMThread
+ guarantee(thread->is_VM_thread(), "can only be called for VMThread");
+ }
+ do_resume(osthread);
+ }
+ // failure means pthread_kill failed for some reason - arguably this is
+ // a fatal problem, but such problems are ignored elsewhere
+
+ return epc;
+}
+
+int os::Linux::safe_cond_timedwait(pthread_cond_t *_cond, pthread_mutex_t *_mutex, const struct timespec *_abstime)
+{
+ if (is_NPTL()) {
+ return pthread_cond_timedwait(_cond, _mutex, _abstime);
+ } else {
+#ifndef IA64
+ // 6292965: LinuxThreads pthread_cond_timedwait() resets FPU control
+ // word back to default 64bit precision if condvar is signaled. Java
+ // wants 53bit precision. Save and restore current value.
+ int fpu = get_fpu_control_word();
+#endif // IA64
+ int status = pthread_cond_timedwait(_cond, _mutex, _abstime);
+#ifndef IA64
+ set_fpu_control_word(fpu);
+#endif // IA64
+ return status;
+ }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// debug support
+
+#ifndef PRODUCT
+static address same_page(address x, address y) {
+ int page_bits = -os::vm_page_size();
+ if ((intptr_t(x) & page_bits) == (intptr_t(y) & page_bits))
+ return x;
+ else if (x > y)
+ return (address)(intptr_t(y) | ~page_bits) + 1;
+ else
+ return (address)(intptr_t(y) & page_bits);
+}
+
+bool os::find(address addr) {
+ Dl_info dlinfo;
+ memset(&dlinfo, 0, sizeof(dlinfo));
+ if (dladdr(addr, &dlinfo)) {
+ tty->print(PTR_FORMAT ": ", addr);
+ if (dlinfo.dli_sname != NULL) {
+ tty->print("%s+%#x", dlinfo.dli_sname,
+ addr - (intptr_t)dlinfo.dli_saddr);
+ } else if (dlinfo.dli_fname) {
+ tty->print("<offset %#x>", addr - (intptr_t)dlinfo.dli_fbase);
+ } else {
+ tty->print("<absolute address>");
+ }
+ if (dlinfo.dli_fname) {
+ tty->print(" in %s", dlinfo.dli_fname);
+ }
+ if (dlinfo.dli_fbase) {
+ tty->print(" at " PTR_FORMAT, dlinfo.dli_fbase);
+ }
+ tty->cr();
+
+ if (Verbose) {
+ // decode some bytes around the PC
+ address begin = same_page(addr-40, addr);
+ address end = same_page(addr+40, addr);
+ address lowest = (address) dlinfo.dli_sname;
+ if (!lowest) lowest = (address) dlinfo.dli_fbase;
+ if (begin < lowest) begin = lowest;
+ Dl_info dlinfo2;
+ if (dladdr(end, &dlinfo2) && dlinfo2.dli_saddr != dlinfo.dli_saddr
+ && end > dlinfo2.dli_saddr && dlinfo2.dli_saddr > begin)
+ end = (address) dlinfo2.dli_saddr;
+ Disassembler::decode(begin, end);
+ }
+ return true;
+ }
+ return false;
+}
+
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+// misc
+
+// This does not do anything on Linux. This is basically a hook for being
+// able to use structured exception handling (thread-local exception filters)
+// on, e.g., Win32.
+void
+os::os_exception_wrapper(java_call_t f, JavaValue* value, methodHandle* method,
+ JavaCallArguments* args, Thread* thread) {
+ f(value, method, args, thread);
+}
+
+void os::print_statistics() {
+}
+
+int os::message_box(const char* title, const char* message) {
+ int i;
+ fdStream err(defaultStream::error_fd());
+ for (i = 0; i < 78; i++) err.print_raw("=");
+ err.cr();
+ err.print_raw_cr(title);
+ for (i = 0; i < 78; i++) err.print_raw("-");
+ err.cr();
+ err.print_raw_cr(message);
+ for (i = 0; i < 78; i++) err.print_raw("=");
+ err.cr();
+
+ char buf[16];
+ // Prevent process from exiting upon "read error" without consuming all CPU
+ while (::read(0, buf, sizeof(buf)) <= 0) { ::sleep(100); }
+
+ return buf[0] == 'y' || buf[0] == 'Y';
+}
+
+int os::stat(const char *path, struct stat *sbuf) {
+ char pathbuf[MAX_PATH];
+ if (strlen(path) > MAX_PATH - 1) {
+ errno = ENAMETOOLONG;
+ return -1;
+ }
+ hpi::native_path(strcpy(pathbuf, path));
+ return ::stat(pathbuf, sbuf);
+}
+
+bool os::check_heap(bool force) {
+ return true;
+}
+
+int local_vsnprintf(char* buf, size_t count, const char* format, va_list args) {
+ return ::vsnprintf(buf, count, format, args);
+}
+
+// Is a (classpath) directory empty?
+bool os::dir_is_empty(const char* path) {
+ DIR *dir = NULL;
+ struct dirent *ptr;
+
+ dir = opendir(path);
+ if (dir == NULL) return true;
+
+ /* Scan the directory */
+ bool result = true;
+ char buf[sizeof(struct dirent) + MAX_PATH];
+ while (result && (ptr = ::readdir(dir)) != NULL) {
+ if (strcmp(ptr->d_name, ".") != 0 && strcmp(ptr->d_name, "..") != 0) {
+ result = false;
+ }
+ }
+ closedir(dir);
+ return result;
+}
+
+// create binary file, rewriting existing file if required
+int os::create_binary_file(const char* path, bool rewrite_existing) {
+ int oflags = O_WRONLY | O_CREAT;
+ if (!rewrite_existing) {
+ oflags |= O_EXCL;
+ }
+ return ::open64(path, oflags, S_IREAD | S_IWRITE);
+}
+
+// return current position of file pointer
+jlong os::current_file_offset(int fd) {
+ return (jlong)::lseek64(fd, (off64_t)0, SEEK_CUR);
+}
+
+// move file pointer to the specified offset
+jlong os::seek_to_file_offset(int fd, jlong offset) {
+ return (jlong)::lseek64(fd, (off64_t)offset, SEEK_SET);
+}
+
+// Map a block of memory.
+char* os::map_memory(int fd, const char* file_name, size_t file_offset,
+ char *addr, size_t bytes, bool read_only,
+ bool allow_exec) {
+ int prot;
+ int flags;
+
+ if (read_only) {
+ prot = PROT_READ;
+ flags = MAP_SHARED;
+ } else {
+ prot = PROT_READ | PROT_WRITE;
+ flags = MAP_PRIVATE;
+ }
+
+ if (allow_exec) {
+ prot |= PROT_EXEC;
+ }
+
+ if (addr != NULL) {
+ flags |= MAP_FIXED;
+ }
+
+ char* mapped_address = (char*)mmap(addr, (size_t)bytes, prot, flags,
+ fd, file_offset);
+ if (mapped_address == MAP_FAILED) {
+ return NULL;
+ }
+ return mapped_address;
+}
+
+
+// Remap a block of memory.
+char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
+ char *addr, size_t bytes, bool read_only,
+ bool allow_exec) {
+ // same as map_memory() on this OS
+ return os::map_memory(fd, file_name, file_offset, addr, bytes, read_only,
+ allow_exec);
+}
+
+
+// Unmap a block of memory.
+bool os::unmap_memory(char* addr, size_t bytes) {
+ return munmap(addr, bytes) == 0;
+}
+
+static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time);
+
+static clockid_t thread_cpu_clockid(Thread* thread) {
+ pthread_t tid = thread->osthread()->pthread_id();
+ clockid_t clockid;
+
+ // Get thread clockid
+ int rc = os::Linux::pthread_getcpuclockid(tid, &clockid);
+ assert(rc == 0, "pthread_getcpuclockid is expected to return 0 code");
+ return clockid;
+}
+
+// current_thread_cpu_time(bool) and thread_cpu_time(Thread*, bool)
+// are used by JVM M&M and JVMTI to get user+sys or user CPU time
+// of a thread.
+//
+// current_thread_cpu_time() and thread_cpu_time(Thread*) returns
+// the fast estimate available on the platform.
+
+jlong os::current_thread_cpu_time() {
+ if (os::Linux::supports_fast_thread_cpu_time()) {
+ return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
+ } else {
+ // return user + sys since the cost is the same
+ return slow_thread_cpu_time(Thread::current(), true /* user + sys */);
+ }
+}
+
+jlong os::thread_cpu_time(Thread* thread) {
+ // consistent with what current_thread_cpu_time() returns
+ if (os::Linux::supports_fast_thread_cpu_time()) {
+ return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
+ } else {
+ return slow_thread_cpu_time(thread, true /* user + sys */);
+ }
+}
+
+jlong os::current_thread_cpu_time(bool user_sys_cpu_time) {
+ if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
+ return os::Linux::fast_thread_cpu_time(CLOCK_THREAD_CPUTIME_ID);
+ } else {
+ return slow_thread_cpu_time(Thread::current(), user_sys_cpu_time);
+ }
+}
+
+jlong os::thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
+ if (user_sys_cpu_time && os::Linux::supports_fast_thread_cpu_time()) {
+ return os::Linux::fast_thread_cpu_time(thread_cpu_clockid(thread));
+ } else {
+ return slow_thread_cpu_time(thread, user_sys_cpu_time);
+ }
+}
+
+//
+// -1 on error.
+//
+
+static jlong slow_thread_cpu_time(Thread *thread, bool user_sys_cpu_time) {
+ static bool proc_pid_cpu_avail = true;
+ static bool proc_task_unchecked = true;
+ static const char *proc_stat_path = "/proc/%d/stat";
+ pid_t tid = thread->osthread()->thread_id();
+ int i;
+ char *s;
+ char stat[2048];
+ int statlen;
+ char proc_name[64];
+ int count;
+ long sys_time, user_time;
+ char string[64];
+ int idummy;
+ long ldummy;
+ FILE *fp;
+
+ // We first try accessing /proc/<pid>/cpu since this is faster to
+ // process. If this file is not present (linux kernels 2.5 and above)
+ // then we open /proc/<pid>/stat.
+ if ( proc_pid_cpu_avail ) {
+ sprintf(proc_name, "/proc/%d/cpu", tid);
+ fp = fopen(proc_name, "r");
+ if ( fp != NULL ) {
+ count = fscanf( fp, "%s %lu %lu\n", string, &user_time, &sys_time);
+ fclose(fp);
+ if ( count != 3 ) return -1;
+
+ if (user_sys_cpu_time) {
+ return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
+ } else {
+ return (jlong)user_time * (1000000000 / clock_tics_per_sec);
+ }
+ }
+ else proc_pid_cpu_avail = false;
+ }
+
+ // The /proc/<tid>/stat aggregates per-process usage on
+ // new Linux kernels 2.6+ where NPTL is supported.
+ // The /proc/self/task/<tid>/stat still has the per-thread usage.
+ // See bug 6328462.
+ // There can be no directory /proc/self/task on kernels 2.4 with NPTL
+ // and possibly in some other cases, so we check its availability.
+ if (proc_task_unchecked && os::Linux::is_NPTL()) {
+ // This is executed only once
+ proc_task_unchecked = false;
+ fp = fopen("/proc/self/task", "r");
+ if (fp != NULL) {
+ proc_stat_path = "/proc/self/task/%d/stat";
+ fclose(fp);
+ }
+ }
+
+ sprintf(proc_name, proc_stat_path, tid);
+ fp = fopen(proc_name, "r");
+ if ( fp == NULL ) return -1;
+ statlen = fread(stat, 1, 2047, fp);
+ stat[statlen] = '\0';
+ fclose(fp);
+
+ // Skip pid and the command string. Note that we could be dealing with
+ // weird command names, e.g. user could decide to rename java launcher
+ // to "java 1.4.2 :)", then the stat file would look like
+ // 1234 (java 1.4.2 :)) R ... ...
+ // We don't really need to know the command string, just find the last
+ // occurrence of ")" and then start parsing from there. See bug 4726580.
+ s = strrchr(stat, ')');
+ i = 0;
+ if (s == NULL ) return -1;
+
+ // Skip blank chars
+ do s++; while (isspace(*s));
+
+ count = sscanf(s,"%c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu",
+ &idummy, &idummy, &idummy, &idummy, &idummy, &idummy,
+ &ldummy, &ldummy, &ldummy, &ldummy, &ldummy,
+ &user_time, &sys_time);
+ if ( count != 13 ) return -1;
+ if (user_sys_cpu_time) {
+ return ((jlong)sys_time + (jlong)user_time) * (1000000000 / clock_tics_per_sec);
+ } else {
+ return (jlong)user_time * (1000000000 / clock_tics_per_sec);
+ }
+}
+
+void os::current_thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
+ info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
+ info_ptr->may_skip_backward = false; // elapsed time not wall time
+ info_ptr->may_skip_forward = false; // elapsed time not wall time
+ info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
+}
+
+void os::thread_cpu_time_info(jvmtiTimerInfo *info_ptr) {
+ info_ptr->max_value = ALL_64_BITS; // will not wrap in less than 64 bits
+ info_ptr->may_skip_backward = false; // elapsed time not wall time
+ info_ptr->may_skip_forward = false; // elapsed time not wall time
+ info_ptr->kind = JVMTI_TIMER_TOTAL_CPU; // user+system time is returned
+}
+
+bool os::is_thread_cpu_time_supported() {
+ return true;
+}
+
+// System loadavg support. Returns -1 if load average cannot be obtained.
+// Linux doesn't yet have a (official) notion of processor sets,
+// so just return the system wide load average.
+int os::loadavg(double loadavg[], int nelem) {
+ return ::getloadavg(loadavg, nelem);
+}
+
+void os::pause() {
+ char filename[MAX_PATH];
+ if (PauseAtStartupFile && PauseAtStartupFile[0]) {
+ jio_snprintf(filename, MAX_PATH, PauseAtStartupFile);
+ } else {
+ jio_snprintf(filename, MAX_PATH, "./vm.paused.%d", current_process_id());
+ }
+
+ int fd = ::open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
+ if (fd != -1) {
+ struct stat buf;
+ close(fd);
+ while (::stat(filename, &buf) == 0) {
+ (void)::poll(NULL, 0, 100);
+ }
+ } else {
+ jio_fprintf(stderr,
+ "Could not open pause file '%s', continuing immediately.\n", filename);
+ }
+}
+
+extern "C" {
+
+/**
+ * NOTE: the following code is to keep the green threads code
+ * in the libjava.so happy. Once the green threads is removed,
+ * these code will no longer be needed.
+ */
+int
+jdk_waitpid(pid_t pid, int* status, int options) {
+ return waitpid(pid, status, options);
+}
+
+int
+fork1() {
+ return fork();
+}
+
+int
+jdk_sem_init(sem_t *sem, int pshared, unsigned int value) {
+ return sem_init(sem, pshared, value);
+}
+
+int
+jdk_sem_post(sem_t *sem) {
+ return sem_post(sem);
+}
+
+int
+jdk_sem_wait(sem_t *sem) {
+ return sem_wait(sem);
+}
+
+int
+jdk_pthread_sigmask(int how , const sigset_t* newmask, sigset_t* oldmask) {
+ return pthread_sigmask(how , newmask, oldmask);
+}
+
+}
+
+// Refer to the comments in os_solaris.cpp park-unpark.
+//
+// Beware -- Some versions of NPTL embody a flaw where pthread_cond_timedwait() can
+// hang indefinitely. For instance NPTL 0.60 on 2.4.21-4ELsmp is vulnerable.
+// For specifics regarding the bug see GLIBC BUGID 261237 :
+// http://www.mail-archive.com/debian-glibc@lists.debian.org/msg10837.html.
+// Briefly, pthread_cond_timedwait() calls with an expiry time that's not in the future
+// will either hang or corrupt the condvar, resulting in subsequent hangs if the condvar
+// is used. (The simple C test-case provided in the GLIBC bug report manifests the
+// hang). The JVM is vulernable via sleep(), Object.wait(timo), LockSupport.parkNanos()
+// and monitorenter when we're using 1-0 locking. All those operations may result in
+// calls to pthread_cond_timedwait(). Using LD_ASSUME_KERNEL to use an older version
+// of libpthread avoids the problem, but isn't practical.
+//
+// Possible remedies:
+//
+// 1. Establish a minimum relative wait time. 50 to 100 msecs seems to work.
+// This is palliative and probabilistic, however. If the thread is preempted
+// between the call to compute_abstime() and pthread_cond_timedwait(), more
+// than the minimum period may have passed, and the abstime may be stale (in the
+// past) resultin in a hang. Using this technique reduces the odds of a hang
+// but the JVM is still vulnerable, particularly on heavily loaded systems.
+//
+// 2. Modify park-unpark to use per-thread (per ParkEvent) pipe-pairs instead
+// of the usual flag-condvar-mutex idiom. The write side of the pipe is set
+// NDELAY. unpark() reduces to write(), park() reduces to read() and park(timo)
+// reduces to poll()+read(). This works well, but consumes 2 FDs per extant
+// thread.
+//
+// 3. Embargo pthread_cond_timedwait() and implement a native "chron" thread
+// that manages timeouts. We'd emulate pthread_cond_timedwait() by enqueuing
+// a timeout request to the chron thread and then blocking via pthread_cond_wait().
+// This also works well. In fact it avoids kernel-level scalability impediments
+// on certain platforms that don't handle lots of active pthread_cond_timedwait()
+// timers in a graceful fashion.
+//
+// 4. When the abstime value is in the past it appears that control returns
+// correctly from pthread_cond_timedwait(), but the condvar is left corrupt.
+// Subsequent timedwait/wait calls may hang indefinitely. Given that, we
+// can avoid the problem by reinitializing the condvar -- by cond_destroy()
+// followed by cond_init() -- after all calls to pthread_cond_timedwait().
+// It may be possible to avoid reinitialization by checking the return
+// value from pthread_cond_timedwait(). In addition to reinitializing the
+// condvar we must establish the invariant that cond_signal() is only called
+// within critical sections protected by the adjunct mutex. This prevents
+// cond_signal() from "seeing" a condvar that's in the midst of being
+// reinitialized or that is corrupt. Sadly, this invariant obviates the
+// desirable signal-after-unlock optimization that avoids futile context switching.
+//
+// I'm also concerned that some versions of NTPL might allocate an auxilliary
+// structure when a condvar is used or initialized. cond_destroy() would
+// release the helper structure. Our reinitialize-after-timedwait fix
+// put excessive stress on malloc/free and locks protecting the c-heap.
+//
+// We currently use (4). See the WorkAroundNTPLTimedWaitHang flag.
+// It may be possible to refine (4) by checking the kernel and NTPL verisons
+// and only enabling the work-around for vulnerable environments.
+
+// utility to compute the abstime argument to timedwait:
+// millis is the relative timeout time
+// abstime will be the absolute timeout time
+// TODO: replace compute_abstime() with unpackTime()
+
+static struct timespec* compute_abstime(timespec* abstime, jlong millis) {
+ if (millis < 0) millis = 0;
+ struct timeval now;
+ int status = gettimeofday(&now, NULL);
+ assert(status == 0, "gettimeofday");
+ jlong seconds = millis / 1000;
+ millis %= 1000;
+ if (seconds > 50000000) { // see man cond_timedwait(3T)
+ seconds = 50000000;
+ }
+ abstime->tv_sec = now.tv_sec + seconds;
+ long usec = now.tv_usec + millis * 1000;
+ if (usec >= 1000000) {
+ abstime->tv_sec += 1;
+ usec -= 1000000;
+ }
+ abstime->tv_nsec = usec * 1000;
+ return abstime;
+}
+
+
+// Test-and-clear _Event, always leaves _Event set to 0, returns immediately.
+// Conceptually TryPark() should be equivalent to park(0).
+
+int os::PlatformEvent::TryPark() {
+ for (;;) {
+ const int v = _Event ;
+ guarantee ((v == 0) || (v == 1), "invariant") ;
+ if (Atomic::cmpxchg (0, &_Event, v) == v) return v ;
+ }
+}
+
+void os::PlatformEvent::park() { // AKA "down()"
+ // Invariant: Only the thread associated with the Event/PlatformEvent
+ // may call park().
+ // TODO: assert that _Assoc != NULL or _Assoc == Self
+ int v ;
+ for (;;) {
+ v = _Event ;
+ if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
+ }
+ guarantee (v >= 0, "invariant") ;
+ if (v == 0) {
+ // Do this the hard way by blocking ...
+ int status = pthread_mutex_lock(_mutex);
+ assert_status(status == 0, status, "mutex_lock");
+ guarantee (_nParked == 0, "invariant") ;
+ ++ _nParked ;
+ while (_Event < 0) {
+ status = pthread_cond_wait(_cond, _mutex);
+ // for some reason, under 2.7 lwp_cond_wait() may return ETIME ...
+ // Treat this the same as if the wait was interrupted
+ if (status == ETIME) { status = EINTR; }
+ assert_status(status == 0 || status == EINTR, status, "cond_wait");
+ }
+ -- _nParked ;
+
+ // In theory we could move the ST of 0 into _Event past the unlock(),
+ // but then we'd need a MEMBAR after the ST.
+ _Event = 0 ;
+ status = pthread_mutex_unlock(_mutex);
+ assert_status(status == 0, status, "mutex_unlock");
+ }
+ guarantee (_Event >= 0, "invariant") ;
+}
+
+int os::PlatformEvent::park(jlong millis) {
+ guarantee (_nParked == 0, "invariant") ;
+
+ int v ;
+ for (;;) {
+ v = _Event ;
+ if (Atomic::cmpxchg (v-1, &_Event, v) == v) break ;
+ }
+ guarantee (v >= 0, "invariant") ;
+ if (v != 0) return OS_OK ;
+
+ // We do this the hard way, by blocking the thread.
+ // Consider enforcing a minimum timeout value.
+ struct timespec abst;
+ compute_abstime(&abst, millis);
+
+ int ret = OS_TIMEOUT;
+ int status = pthread_mutex_lock(_mutex);
+ assert_status(status == 0, status, "mutex_lock");
+ guarantee (_nParked == 0, "invariant") ;
+ ++_nParked ;
+
+ // Object.wait(timo) will return because of
+ // (a) notification
+ // (b) timeout
+ // (c) thread.interrupt
+ //
+ // Thread.interrupt and object.notify{All} both call Event::set.
+ // That is, we treat thread.interrupt as a special case of notification.
+ // The underlying Solaris implementation, cond_timedwait, admits
+ // spurious/premature wakeups, but the JLS/JVM spec prevents the
+ // JVM from making those visible to Java code. As such, we must
+ // filter out spurious wakeups. We assume all ETIME returns are valid.
+ //
+ // TODO: properly differentiate simultaneous notify+interrupt.
+ // In that case, we should propagate the notify to another waiter.
+
+ while (_Event < 0) {
+ status = os::Linux::safe_cond_timedwait(_cond, _mutex, &abst);
+ if (status != 0 && WorkAroundNPTLTimedWaitHang) {
+ pthread_cond_destroy (_cond);
+ pthread_cond_init (_cond, NULL) ;
+ }
+ assert_status(status == 0 || status == EINTR ||
+ status == ETIME || status == ETIMEDOUT,
+ status, "cond_timedwait");
+ if (!FilterSpuriousWakeups) break ; // previous semantics
+ if (status == ETIME || status == ETIMEDOUT) break ;
+ // We consume and ignore EINTR and spurious wakeups.
+ }
+ --_nParked ;
+ if (_Event >= 0) {
+ ret = OS_OK;
+ }
+ _Event = 0 ;
+ status = pthread_mutex_unlock(_mutex);
+ assert_status(status == 0, status, "mutex_unlock");
+ assert (_nParked == 0, "invariant") ;
+ return ret;
+}
+
+void os::PlatformEvent::unpark() {
+ int v, AnyWaiters ;
+ for (;;) {
+ v = _Event ;
+ if (v > 0) {
+ // The LD of _Event could have reordered or be satisfied
+ // by a read-aside from this processor's write buffer.
+ // To avoid problems execute a barrier and then
+ // ratify the value.
+ OrderAccess::fence() ;
+ if (_Event == v) return ;
+ continue ;
+ }
+ if (Atomic::cmpxchg (v+1, &_Event, v) == v) break ;
+ }
+ if (v < 0) {
+ // Wait for the thread associated with the event to vacate
+ int status = pthread_mutex_lock(_mutex);
+ assert_status(status == 0, status, "mutex_lock");
+ AnyWaiters = _nParked ;
+ assert (AnyWaiters == 0 || AnyWaiters == 1, "invariant") ;
+ if (AnyWaiters != 0 && WorkAroundNPTLTimedWaitHang) {
+ AnyWaiters = 0 ;
+ pthread_cond_signal (_cond);
+ }
+ status = pthread_mutex_unlock(_mutex);
+ assert_status(status == 0, status, "mutex_unlock");
+ if (AnyWaiters != 0) {
+ status = pthread_cond_signal(_cond);
+ assert_status(status == 0, status, "cond_signal");
+ }
+ }
+
+ // Note that we signal() _after dropping the lock for "immortal" Events.
+ // This is safe and avoids a common class of futile wakeups. In rare
+ // circumstances this can cause a thread to return prematurely from
+ // cond_{timed}wait() but the spurious wakeup is benign and the victim will
+ // simply re-test the condition and re-park itself.
+}
+
+
+// JSR166
+// -------------------------------------------------------
+
+/*
+ * The solaris and linux implementations of park/unpark are fairly
+ * conservative for now, but can be improved. They currently use a
+ * mutex/condvar pair, plus a a count.
+ * Park decrements count if > 0, else does a condvar wait. Unpark
+ * sets count to 1 and signals condvar. Only one thread ever waits
+ * on the condvar. Contention seen when trying to park implies that someone
+ * is unparking you, so don't wait. And spurious returns are fine, so there
+ * is no need to track notifications.
+ */
+
+
+#define NANOSECS_PER_SEC 1000000000
+#define NANOSECS_PER_MILLISEC 1000000
+#define MAX_SECS 100000000
+/*
+ * This code is common to linux and solaris and will be moved to a
+ * common place in dolphin.
+ *
+ * The passed in time value is either a relative time in nanoseconds
+ * or an absolute time in milliseconds. Either way it has to be unpacked
+ * into suitable seconds and nanoseconds components and stored in the
+ * given timespec structure.
+ * Given time is a 64-bit value and the time_t used in the timespec is only
+ * a signed-32-bit value (except on 64-bit Linux) we have to watch for
+ * overflow if times way in the future are given. Further on Solaris versions
+ * prior to 10 there is a restriction (see cond_timedwait) that the specified
+ * number of seconds, in abstime, is less than current_time + 100,000,000.
+ * As it will be 28 years before "now + 100000000" will overflow we can
+ * ignore overflow and just impose a hard-limit on seconds using the value
+ * of "now + 100,000,000". This places a limit on the timeout of about 3.17
+ * years from "now".
+ */
+
+static void unpackTime(timespec* absTime, bool isAbsolute, jlong time) {
+ assert (time > 0, "convertTime");
+
+ struct timeval now;
+ int status = gettimeofday(&now, NULL);
+ assert(status == 0, "gettimeofday");
+
+ time_t max_secs = now.tv_sec + MAX_SECS;
+
+ if (isAbsolute) {
+ jlong secs = time / 1000;
+ if (secs > max_secs) {
+ absTime->tv_sec = max_secs;
+ }
+ else {
+ absTime->tv_sec = secs;
+ }
+ absTime->tv_nsec = (time % 1000) * NANOSECS_PER_MILLISEC;
+ }
+ else {
+ jlong secs = time / NANOSECS_PER_SEC;
+ if (secs >= MAX_SECS) {
+ absTime->tv_sec = max_secs;
+ absTime->tv_nsec = 0;
+ }
+ else {
+ absTime->tv_sec = now.tv_sec + secs;
+ absTime->tv_nsec = (time % NANOSECS_PER_SEC) + now.tv_usec*1000;
+ if (absTime->tv_nsec >= NANOSECS_PER_SEC) {
+ absTime->tv_nsec -= NANOSECS_PER_SEC;
+ ++absTime->tv_sec; // note: this must be <= max_secs
+ }
+ }
+ }
+ assert(absTime->tv_sec >= 0, "tv_sec < 0");
+ assert(absTime->tv_sec <= max_secs, "tv_sec > max_secs");
+ assert(absTime->tv_nsec >= 0, "tv_nsec < 0");
+ assert(absTime->tv_nsec < NANOSECS_PER_SEC, "tv_nsec >= nanos_per_sec");
+}
+
+void Parker::park(bool isAbsolute, jlong time) {
+ // Optional fast-path check:
+ // Return immediately if a permit is available.
+ if (_counter > 0) {
+ _counter = 0 ;
+ return ;
+ }
+
+ Thread* thread = Thread::current();
+ assert(thread->is_Java_thread(), "Must be JavaThread");
+ JavaThread *jt = (JavaThread *)thread;
+
+ // Optional optimization -- avoid state transitions if there's an interrupt pending.
+ // Check interrupt before trying to wait
+ if (Thread::is_interrupted(thread, false)) {
+ return;
+ }
+
+ // Next, demultiplex/decode time arguments
+ timespec absTime;
+ if (time < 0) { // don't wait at all
+ return;
+ }
+ if (time > 0) {
+ unpackTime(&absTime, isAbsolute, time);
+ }
+
+
+ // Enter safepoint region
+ // Beware of deadlocks such as 6317397.
+ // The per-thread Parker:: mutex is a classic leaf-lock.
+ // In particular a thread must never block on the Threads_lock while
+ // holding the Parker:: mutex. If safepoints are pending both the
+ // the ThreadBlockInVM() CTOR and DTOR may grab Threads_lock.
+ ThreadBlockInVM tbivm(jt);
+
+ // Don't wait if cannot get lock since interference arises from
+ // unblocking. Also. check interrupt before trying wait
+ if (Thread::is_interrupted(thread, false) || pthread_mutex_trylock(_mutex) != 0) {
+ return;
+ }
+
+ int status ;
+ if (_counter > 0) { // no wait needed
+ _counter = 0;
+ status = pthread_mutex_unlock(_mutex);
+ assert (status == 0, "invariant") ;
+ return;
+ }
+
+#ifdef ASSERT
+ // Don't catch signals while blocked; let the running threads have the signals.
+ // (This allows a debugger to break into the running thread.)
+ sigset_t oldsigs;
+ sigset_t* allowdebug_blocked = os::Linux::allowdebug_blocked_signals();
+ pthread_sigmask(SIG_BLOCK, allowdebug_blocked, &oldsigs);
+#endif
+
+ OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
+ jt->set_suspend_equivalent();
+ // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
+
+ if (time == 0) {
+ status = pthread_cond_wait (_cond, _mutex) ;
+ } else {
+ status = os::Linux::safe_cond_timedwait (_cond, _mutex, &absTime) ;
+ if (status != 0 && WorkAroundNPTLTimedWaitHang) {
+ pthread_cond_destroy (_cond) ;
+ pthread_cond_init (_cond, NULL);
+ }
+ }
+ assert_status(status == 0 || status == EINTR ||
+ status == ETIME || status == ETIMEDOUT,
+ status, "cond_timedwait");
+
+#ifdef ASSERT
+ pthread_sigmask(SIG_SETMASK, &oldsigs, NULL);
+#endif
+
+ _counter = 0 ;
+ status = pthread_mutex_unlock(_mutex) ;
+ assert_status(status == 0, status, "invariant") ;
+ // If externally suspended while waiting, re-suspend
+ if (jt->handle_special_suspend_equivalent_condition()) {
+ jt->java_suspend_self();
+ }
+
+}
+
+void Parker::unpark() {
+ int s, status ;
+ status = pthread_mutex_lock(_mutex);
+ assert (status == 0, "invariant") ;
+ s = _counter;
+ _counter = 1;
+ if (s < 1) {
+ if (WorkAroundNPTLTimedWaitHang) {
+ status = pthread_cond_signal (_cond) ;
+ assert (status == 0, "invariant") ;
+ status = pthread_mutex_unlock(_mutex);
+ assert (status == 0, "invariant") ;
+ } else {
+ status = pthread_mutex_unlock(_mutex);
+ assert (status == 0, "invariant") ;
+ status = pthread_cond_signal (_cond) ;
+ assert (status == 0, "invariant") ;
+ }
+ } else {
+ pthread_mutex_unlock(_mutex);
+ assert (status == 0, "invariant") ;
+ }
+}
+
+
+extern char** environ;
+
+#ifndef __NR_fork
+#define __NR_fork IA32_ONLY(2) IA64_ONLY(not defined) AMD64_ONLY(57)
+#endif
+
+#ifndef __NR_execve
+#define __NR_execve IA32_ONLY(11) IA64_ONLY(1033) AMD64_ONLY(59)
+#endif
+
+// Run the specified command in a separate process. Return its exit value,
+// or -1 on failure (e.g. can't fork a new process).
+// Unlike system(), this function can be called from signal handler. It
+// doesn't block SIGINT et al.
+int os::fork_and_exec(char* cmd) {
+ char * argv[4];
+ argv[0] = "sh";
+ argv[1] = "-c";
+ argv[2] = cmd;
+ argv[3] = NULL;
+
+ // fork() in LinuxThreads/NPTL is not async-safe. It needs to run
+ // pthread_atfork handlers and reset pthread library. All we need is a
+ // separate process to execve. Make a direct syscall to fork process.
+ // On IA64 there's no fork syscall, we have to use fork() and hope for
+ // the best...
+ pid_t pid = NOT_IA64(syscall(__NR_fork);)
+ IA64_ONLY(fork();)
+
+ if (pid < 0) {
+ // fork failed
+ return -1;
+
+ } else if (pid == 0) {
+ // child process
+
+ // execve() in LinuxThreads will call pthread_kill_other_threads_np()
+ // first to kill every thread on the thread list. Because this list is
+ // not reset by fork() (see notes above), execve() will instead kill
+ // every thread in the parent process. We know this is the only thread
+ // in the new process, so make a system call directly.
+ // IA64 should use normal execve() from glibc to match the glibc fork()
+ // above.
+ NOT_IA64(syscall(__NR_execve, "/bin/sh", argv, environ);)
+ IA64_ONLY(execve("/bin/sh", argv, environ);)
+
+ // execve failed
+ _exit(-1);
+
+ } else {
+ // copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
+ // care about the actual exit code, for now.
+
+ int status;
+
+ // Wait for the child process to exit. This returns immediately if
+ // the child has already exited. */
+ while (waitpid(pid, &status, 0) < 0) {
+ switch (errno) {
+ case ECHILD: return 0;
+ case EINTR: break;
+ default: return -1;
+ }
+ }
+
+ if (WIFEXITED(status)) {
+ // The child exited normally; get its exit code.
+ return WEXITSTATUS(status);
+ } else if (WIFSIGNALED(status)) {
+ // The child exited because of a signal
+ // The best value to return is 0x80 + signal number,
+ // because that is what all Unix shells do, and because
+ // it allows callers to distinguish between process exit and
+ // process death by signal.
+ return 0x80 + WTERMSIG(status);
+ } else {
+ // Unknown exit code; pass it through
+ return status;
+ }
+ }
+}