/* * Copyright (c) 1999, 2017, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "jvm.h" #include "utilities/globalDefinitions.hpp" #include "runtime/frame.inline.hpp" #include "runtime/interfaceSupport.hpp" #include "runtime/os.hpp" #include "utilities/align.hpp" #include "utilities/macros.hpp" #include "utilities/vmError.hpp" #ifndef __APPLE__ // POSIX unamed semaphores are not supported on OS X. #include "semaphore_posix.hpp" #endif #include #include #include #include #include #include #include #include #include // Todo: provide a os::get_max_process_id() or similar. Number of processes // may have been configured, can be read more accurately from proc fs etc. #ifndef MAX_PID #define MAX_PID INT_MAX #endif #define IS_VALID_PID(p) (p > 0 && p < MAX_PID) #ifndef MAP_ANONYMOUS #define MAP_ANONYMOUS MAP_ANON #endif #define check_with_errno(check_type, cond, msg) \ do { \ int err = errno; \ check_type(cond, "%s; error='%s' (errno=%s)", msg, os::strerror(err), \ os::errno_name(err)); \ } while (false) #define assert_with_errno(cond, msg) check_with_errno(assert, cond, msg) #define guarantee_with_errno(cond, msg) check_with_errno(guarantee, cond, msg) // Check core dump limit and report possible place where core can be found void os::check_dump_limit(char* buffer, size_t bufferSize) { if (!FLAG_IS_DEFAULT(CreateCoredumpOnCrash) && !CreateCoredumpOnCrash) { jio_snprintf(buffer, bufferSize, "CreateCoredumpOnCrash is disabled from command line"); VMError::record_coredump_status(buffer, false); return; } int n; struct rlimit rlim; bool success; char core_path[PATH_MAX]; n = get_core_path(core_path, PATH_MAX); if (n <= 0) { jio_snprintf(buffer, bufferSize, "core.%d (may not exist)", current_process_id()); success = true; #ifdef LINUX } else if (core_path[0] == '"') { // redirect to user process jio_snprintf(buffer, bufferSize, "Core dumps may be processed with %s", core_path); success = true; #endif } else if (getrlimit(RLIMIT_CORE, &rlim) != 0) { jio_snprintf(buffer, bufferSize, "%s (may not exist)", core_path); success = true; } else { switch(rlim.rlim_cur) { case RLIM_INFINITY: jio_snprintf(buffer, bufferSize, "%s", core_path); success = true; break; case 0: jio_snprintf(buffer, bufferSize, "Core dumps have been disabled. To enable core dumping, try \"ulimit -c unlimited\" before starting Java again"); success = false; break; default: jio_snprintf(buffer, bufferSize, "%s (max size " UINT64_FORMAT " kB). To ensure a full core dump, try \"ulimit -c unlimited\" before starting Java again", core_path, uint64_t(rlim.rlim_cur) / 1024); success = true; break; } } VMError::record_coredump_status(buffer, success); } int os::get_native_stack(address* stack, int frames, int toSkip) { int frame_idx = 0; int num_of_frames; // number of frames captured frame fr = os::current_frame(); while (fr.pc() && frame_idx < frames) { if (toSkip > 0) { toSkip --; } else { stack[frame_idx ++] = fr.pc(); } if (fr.fp() == NULL || fr.cb() != NULL || fr.sender_pc() == NULL || os::is_first_C_frame(&fr)) break; if (fr.sender_pc() && !os::is_first_C_frame(&fr)) { fr = os::get_sender_for_C_frame(&fr); } else { break; } } num_of_frames = frame_idx; for (; frame_idx < frames; frame_idx ++) { stack[frame_idx] = NULL; } return num_of_frames; } bool os::unsetenv(const char* name) { assert(name != NULL, "Null pointer"); return (::unsetenv(name) == 0); } int os::get_last_error() { return errno; } bool os::is_debugger_attached() { // not implemented return false; } void os::wait_for_keypress_at_exit(void) { // don't do anything on posix platforms return; } int os::create_file_for_heap(const char* dir) { const char name_template[] = "/jvmheap.XXXXXX"; char *fullname = (char*)os::malloc((strlen(dir) + strlen(name_template) + 1), mtInternal); if (fullname == NULL) { vm_exit_during_initialization(err_msg("Malloc failed during creation of backing file for heap (%s)", os::strerror(errno))); return -1; } (void)strncpy(fullname, dir, strlen(dir)+1); (void)strncat(fullname, name_template, strlen(name_template)); os::native_path(fullname); sigset_t set, oldset; int ret = sigfillset(&set); assert_with_errno(ret == 0, "sigfillset returned error"); // set the file creation mask. mode_t file_mode = S_IRUSR | S_IWUSR; // create a new file. int fd = mkstemp(fullname); if (fd < 0) { warning("Could not create file for heap with template %s", fullname); os::free(fullname); return -1; } // delete the name from the filesystem. When 'fd' is closed, the file (and space) will be deleted. ret = unlink(fullname); assert_with_errno(ret == 0, "unlink returned error"); os::free(fullname); return fd; } static char* reserve_mmapped_memory(size_t bytes, char* requested_addr) { char * addr; int flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS; if (requested_addr != NULL) { assert((uintptr_t)requested_addr % os::vm_page_size() == 0, "Requested address should be aligned to OS page size"); flags |= MAP_FIXED; } // Map reserved/uncommitted pages PROT_NONE so we fail early if we // touch an uncommitted page. Otherwise, the read/write might // succeed if we have enough swap space to back the physical page. addr = (char*)::mmap(requested_addr, bytes, PROT_NONE, flags, -1, 0); if (addr != MAP_FAILED) { MemTracker::record_virtual_memory_reserve((address)addr, bytes, CALLER_PC); return addr; } return NULL; } static int util_posix_fallocate(int fd, off_t offset, off_t len) { #ifdef __APPLE__ fstore_t store = { F_ALLOCATECONTIG, F_PEOFPOSMODE, 0, len }; // First we try to get a continuous chunk of disk space int ret = fcntl(fd, F_PREALLOCATE, &store); if (ret == -1) { // Maybe we are too fragmented, try to allocate non-continuous range store.fst_flags = F_ALLOCATEALL; ret = fcntl(fd, F_PREALLOCATE, &store); } if(ret != -1) { return ftruncate(fd, len); } return -1; #else return posix_fallocate(fd, offset, len); #endif } // Map the given address range to the provided file descriptor. char* os::map_memory_to_file(char* base, size_t size, int fd) { assert(fd != -1, "File descriptor is not valid"); // allocate space for the file if (util_posix_fallocate(fd, 0, (off_t)size) != 0) { vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory.")); return NULL; } int prot = PROT_READ | PROT_WRITE; int flags = MAP_SHARED; if (base != NULL) { flags |= MAP_FIXED; } char* addr = (char*)mmap(base, size, prot, flags, fd, 0); if (addr == MAP_FAILED) { return NULL; } if (base != NULL && addr != base) { if (!os::release_memory(addr, size)) { warning("Could not release memory on unsuccessful file mapping"); } return NULL; } return addr; } char* os::replace_existing_mapping_with_file_mapping(char* base, size_t size, int fd) { assert(fd != -1, "File descriptor is not valid"); assert(base != NULL, "Base cannot be NULL"); return map_memory_to_file(base, size, fd); } // Multiple threads can race in this code, and can remap over each other with MAP_FIXED, // so on posix, unmap the section at the start and at the end of the chunk that we mapped // rather than unmapping and remapping the whole chunk to get requested alignment. char* os::reserve_memory_aligned(size_t size, size_t alignment, int file_desc) { assert((alignment & (os::vm_allocation_granularity() - 1)) == 0, "Alignment must be a multiple of allocation granularity (page size)"); assert((size & (alignment -1)) == 0, "size must be 'alignment' aligned"); size_t extra_size = size + alignment; assert(extra_size >= size, "overflow, size is too large to allow alignment"); char* extra_base; if (file_desc != -1) { // For file mapping, we do not call os:reserve_memory(extra_size, NULL, alignment, file_desc) because // we need to deal with shrinking of the file space later when we release extra memory after alignment. // We also cannot called os:reserve_memory() with file_desc set to -1 because on aix we might get SHM memory. // So here to call a helper function while reserve memory for us. After we have a aligned base, // we will replace anonymous mapping with file mapping. extra_base = reserve_mmapped_memory(extra_size, NULL); if (extra_base != NULL) { MemTracker::record_virtual_memory_reserve((address)extra_base, extra_size, CALLER_PC); } } else { extra_base = os::reserve_memory(extra_size, NULL, alignment); } if (extra_base == NULL) { return NULL; } // Do manual alignment char* aligned_base = align_up(extra_base, alignment); // [ | | ] // ^ extra_base // ^ extra_base + begin_offset == aligned_base // extra_base + begin_offset + size ^ // extra_base + extra_size ^ // |<>| == begin_offset // end_offset == |<>| size_t begin_offset = aligned_base - extra_base; size_t end_offset = (extra_base + extra_size) - (aligned_base + size); if (begin_offset > 0) { os::release_memory(extra_base, begin_offset); } if (end_offset > 0) { os::release_memory(extra_base + begin_offset + size, end_offset); } if (file_desc != -1) { // After we have an aligned address, we can replace anonymous mapping with file mapping if (replace_existing_mapping_with_file_mapping(aligned_base, size, file_desc) == NULL) { vm_exit_during_initialization(err_msg("Error in mapping Java heap at the given filesystem directory")); } MemTracker::record_virtual_memory_commit((address)aligned_base, size, CALLER_PC); } return aligned_base; } int os::log_vsnprintf(char* buf, size_t len, const char* fmt, va_list args) { return vsnprintf(buf, len, fmt, args); } int os::get_fileno(FILE* fp) { return NOT_AIX(::)fileno(fp); } struct tm* os::gmtime_pd(const time_t* clock, struct tm* res) { return gmtime_r(clock, res); } void os::Posix::print_load_average(outputStream* st) { 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::Posix::print_rlimit_info(outputStream* st) { 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(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024); st->print(", CORE "); getrlimit(RLIMIT_CORE, &rlim); if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024); // Isn't there on solaris #if defined(AIX) st->print(", NPROC "); st->print("%d", sysconf(_SC_CHILD_MAX)); #elif !defined(SOLARIS) st->print(", NPROC "); getrlimit(RLIMIT_NPROC, &rlim); if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur)); #endif st->print(", NOFILE "); getrlimit(RLIMIT_NOFILE, &rlim); if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); else st->print(UINT64_FORMAT, uint64_t(rlim.rlim_cur)); st->print(", AS "); getrlimit(RLIMIT_AS, &rlim); if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024); st->print(", DATA "); getrlimit(RLIMIT_DATA, &rlim); if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024); st->print(", FSIZE "); getrlimit(RLIMIT_FSIZE, &rlim); if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity"); else st->print(UINT64_FORMAT "k", uint64_t(rlim.rlim_cur) / 1024); st->cr(); } void os::Posix::print_uname_info(outputStream* st) { // kernel st->print("uname:"); struct utsname name; uname(&name); st->print("%s ", name.sysname); #ifdef ASSERT st->print("%s ", name.nodename); #endif st->print("%s ", name.release); st->print("%s ", name.version); st->print("%s", name.machine); st->cr(); } bool os::get_host_name(char* buf, size_t buflen) { struct utsname name; uname(&name); jio_snprintf(buf, buflen, "%s", name.nodename); return true; } bool os::has_allocatable_memory_limit(julong* limit) { struct rlimit rlim; int getrlimit_res = getrlimit(RLIMIT_AS, &rlim); // if there was an error when calling getrlimit, assume that there is no limitation // on virtual memory. bool result; if ((getrlimit_res != 0) || (rlim.rlim_cur == RLIM_INFINITY)) { result = false; } else { *limit = (julong)rlim.rlim_cur; result = true; } #ifdef _LP64 return result; #else // arbitrary virtual space limit for 32 bit Unices found by testing. If // getrlimit above returned a limit, bound it with this limit. Otherwise // directly use it. const julong max_virtual_limit = (julong)3800*M; if (result) { *limit = MIN2(*limit, max_virtual_limit); } else { *limit = max_virtual_limit; } // bound by actually allocatable memory. The algorithm uses two bounds, an // upper and a lower limit. The upper limit is the current highest amount of // memory that could not be allocated, the lower limit is the current highest // amount of memory that could be allocated. // The algorithm iteratively refines the result by halving the difference // between these limits, updating either the upper limit (if that value could // not be allocated) or the lower limit (if the that value could be allocated) // until the difference between these limits is "small". // the minimum amount of memory we care about allocating. const julong min_allocation_size = M; julong upper_limit = *limit; // first check a few trivial cases if (is_allocatable(upper_limit) || (upper_limit <= min_allocation_size)) { *limit = upper_limit; } else if (!is_allocatable(min_allocation_size)) { // we found that not even min_allocation_size is allocatable. Return it // anyway. There is no point to search for a better value any more. *limit = min_allocation_size; } else { // perform the binary search. julong lower_limit = min_allocation_size; while ((upper_limit - lower_limit) > min_allocation_size) { julong temp_limit = ((upper_limit - lower_limit) / 2) + lower_limit; temp_limit = align_down(temp_limit, min_allocation_size); if (is_allocatable(temp_limit)) { lower_limit = temp_limit; } else { upper_limit = temp_limit; } } *limit = lower_limit; } return true; #endif } const char* os::get_current_directory(char *buf, size_t buflen) { return getcwd(buf, buflen); } FILE* os::open(int fd, const char* mode) { return ::fdopen(fd, mode); } void os::flockfile(FILE* fp) { ::flockfile(fp); } void os::funlockfile(FILE* fp) { ::funlockfile(fp); } // Builds a platform dependent Agent_OnLoad_ function name // which is used to find statically linked in agents. // Parameters: // sym_name: Symbol in library we are looking for // lib_name: Name of library to look in, NULL for shared libs. // is_absolute_path == true if lib_name is absolute path to agent // such as "/a/b/libL.so" // == false if only the base name of the library is passed in // such as "L" char* os::build_agent_function_name(const char *sym_name, const char *lib_name, bool is_absolute_path) { char *agent_entry_name; size_t len; size_t name_len; size_t prefix_len = strlen(JNI_LIB_PREFIX); size_t suffix_len = strlen(JNI_LIB_SUFFIX); const char *start; if (lib_name != NULL) { name_len = strlen(lib_name); if (is_absolute_path) { // Need to strip path, prefix and suffix if ((start = strrchr(lib_name, *os::file_separator())) != NULL) { lib_name = ++start; } if (strlen(lib_name) <= (prefix_len + suffix_len)) { return NULL; } lib_name += prefix_len; name_len = strlen(lib_name) - suffix_len; } } len = (lib_name != NULL ? name_len : 0) + strlen(sym_name) + 2; agent_entry_name = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len, mtThread); if (agent_entry_name == NULL) { return NULL; } strcpy(agent_entry_name, sym_name); if (lib_name != NULL) { strcat(agent_entry_name, "_"); strncat(agent_entry_name, lib_name, name_len); } return agent_entry_name; } 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(!os::supports_monotonic_clock(), "unexpected time moving backwards detected in os::sleep(interruptible)"); } else { millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; } 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(!os::supports_monotonic_clock(), "unexpected time moving backwards detected on os::sleep(!interruptible)"); } else { millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; } if (millis <= 0) break ; prevtime = newtime; slp->park(millis); } return OS_OK ; } } //////////////////////////////////////////////////////////////////////////////// // 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(); // NOTE that since there is no "lock" around the interrupt and // is_interrupted operations, there is the possibility that the // interrupted flag (in osThread) will be "false" but that the // low-level events will be in the signaled state. This is // intentional. The effect of this is that Object.wait() and // LockSupport.park() will appear to have a spurious wakeup, which // is allowed and not harmful, and the possibility is so rare that // it is not worth the added complexity to add yet another lock. // For the sleep event an explicit reset is performed on entry // to os::sleep, so there is no early return. It has also been // recommended not to put the interrupted flag into the "event" // structure because it hides the issue. if (interrupted && clear_interrupted) { osthread->set_interrupted(false); // consider thread->_SleepEvent->reset() ... optional optimization } return interrupted; } static const struct { int sig; const char* name; } g_signal_info[] = { { SIGABRT, "SIGABRT" }, #ifdef SIGAIO { SIGAIO, "SIGAIO" }, #endif { SIGALRM, "SIGALRM" }, #ifdef SIGALRM1 { SIGALRM1, "SIGALRM1" }, #endif { SIGBUS, "SIGBUS" }, #ifdef SIGCANCEL { SIGCANCEL, "SIGCANCEL" }, #endif { SIGCHLD, "SIGCHLD" }, #ifdef SIGCLD { SIGCLD, "SIGCLD" }, #endif { SIGCONT, "SIGCONT" }, #ifdef SIGCPUFAIL { SIGCPUFAIL, "SIGCPUFAIL" }, #endif #ifdef SIGDANGER { SIGDANGER, "SIGDANGER" }, #endif #ifdef SIGDIL { SIGDIL, "SIGDIL" }, #endif #ifdef SIGEMT { SIGEMT, "SIGEMT" }, #endif { SIGFPE, "SIGFPE" }, #ifdef SIGFREEZE { SIGFREEZE, "SIGFREEZE" }, #endif #ifdef SIGGFAULT { SIGGFAULT, "SIGGFAULT" }, #endif #ifdef SIGGRANT { SIGGRANT, "SIGGRANT" }, #endif { SIGHUP, "SIGHUP" }, { SIGILL, "SIGILL" }, { SIGINT, "SIGINT" }, #ifdef SIGIO { SIGIO, "SIGIO" }, #endif #ifdef SIGIOINT { SIGIOINT, "SIGIOINT" }, #endif #ifdef SIGIOT // SIGIOT is there for BSD compatibility, but on most Unices just a // synonym for SIGABRT. The result should be "SIGABRT", not // "SIGIOT". #if (SIGIOT != SIGABRT ) { SIGIOT, "SIGIOT" }, #endif #endif #ifdef SIGKAP { SIGKAP, "SIGKAP" }, #endif { SIGKILL, "SIGKILL" }, #ifdef SIGLOST { SIGLOST, "SIGLOST" }, #endif #ifdef SIGLWP { SIGLWP, "SIGLWP" }, #endif #ifdef SIGLWPTIMER { SIGLWPTIMER, "SIGLWPTIMER" }, #endif #ifdef SIGMIGRATE { SIGMIGRATE, "SIGMIGRATE" }, #endif #ifdef SIGMSG { SIGMSG, "SIGMSG" }, #endif { SIGPIPE, "SIGPIPE" }, #ifdef SIGPOLL { SIGPOLL, "SIGPOLL" }, #endif #ifdef SIGPRE { SIGPRE, "SIGPRE" }, #endif { SIGPROF, "SIGPROF" }, #ifdef SIGPTY { SIGPTY, "SIGPTY" }, #endif #ifdef SIGPWR { SIGPWR, "SIGPWR" }, #endif { SIGQUIT, "SIGQUIT" }, #ifdef SIGRECONFIG { SIGRECONFIG, "SIGRECONFIG" }, #endif #ifdef SIGRECOVERY { SIGRECOVERY, "SIGRECOVERY" }, #endif #ifdef SIGRESERVE { SIGRESERVE, "SIGRESERVE" }, #endif #ifdef SIGRETRACT { SIGRETRACT, "SIGRETRACT" }, #endif #ifdef SIGSAK { SIGSAK, "SIGSAK" }, #endif { SIGSEGV, "SIGSEGV" }, #ifdef SIGSOUND { SIGSOUND, "SIGSOUND" }, #endif #ifdef SIGSTKFLT { SIGSTKFLT, "SIGSTKFLT" }, #endif { SIGSTOP, "SIGSTOP" }, { SIGSYS, "SIGSYS" }, #ifdef SIGSYSERROR { SIGSYSERROR, "SIGSYSERROR" }, #endif #ifdef SIGTALRM { SIGTALRM, "SIGTALRM" }, #endif { SIGTERM, "SIGTERM" }, #ifdef SIGTHAW { SIGTHAW, "SIGTHAW" }, #endif { SIGTRAP, "SIGTRAP" }, #ifdef SIGTSTP { SIGTSTP, "SIGTSTP" }, #endif { SIGTTIN, "SIGTTIN" }, { SIGTTOU, "SIGTTOU" }, #ifdef SIGURG { SIGURG, "SIGURG" }, #endif { SIGUSR1, "SIGUSR1" }, { SIGUSR2, "SIGUSR2" }, #ifdef SIGVIRT { SIGVIRT, "SIGVIRT" }, #endif { SIGVTALRM, "SIGVTALRM" }, #ifdef SIGWAITING { SIGWAITING, "SIGWAITING" }, #endif #ifdef SIGWINCH { SIGWINCH, "SIGWINCH" }, #endif #ifdef SIGWINDOW { SIGWINDOW, "SIGWINDOW" }, #endif { SIGXCPU, "SIGXCPU" }, { SIGXFSZ, "SIGXFSZ" }, #ifdef SIGXRES { SIGXRES, "SIGXRES" }, #endif { -1, NULL } }; // Returned string is a constant. For unknown signals "UNKNOWN" is returned. const char* os::Posix::get_signal_name(int sig, char* out, size_t outlen) { const char* ret = NULL; #ifdef SIGRTMIN if (sig >= SIGRTMIN && sig <= SIGRTMAX) { if (sig == SIGRTMIN) { ret = "SIGRTMIN"; } else if (sig == SIGRTMAX) { ret = "SIGRTMAX"; } else { jio_snprintf(out, outlen, "SIGRTMIN+%d", sig - SIGRTMIN); return out; } } #endif if (sig > 0) { for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) { if (g_signal_info[idx].sig == sig) { ret = g_signal_info[idx].name; break; } } } if (!ret) { if (!is_valid_signal(sig)) { ret = "INVALID"; } else { ret = "UNKNOWN"; } } if (out && outlen > 0) { strncpy(out, ret, outlen); out[outlen - 1] = '\0'; } return out; } int os::Posix::get_signal_number(const char* signal_name) { char tmp[30]; const char* s = signal_name; if (s[0] != 'S' || s[1] != 'I' || s[2] != 'G') { jio_snprintf(tmp, sizeof(tmp), "SIG%s", signal_name); s = tmp; } for (int idx = 0; g_signal_info[idx].sig != -1; idx ++) { if (strcmp(g_signal_info[idx].name, s) == 0) { return g_signal_info[idx].sig; } } return -1; } int os::get_signal_number(const char* signal_name) { return os::Posix::get_signal_number(signal_name); } // Returns true if signal number is valid. bool os::Posix::is_valid_signal(int sig) { // MacOS not really POSIX compliant: sigaddset does not return // an error for invalid signal numbers. However, MacOS does not // support real time signals and simply seems to have just 33 // signals with no holes in the signal range. #ifdef __APPLE__ return sig >= 1 && sig < NSIG; #else // Use sigaddset to check for signal validity. sigset_t set; sigemptyset(&set); if (sigaddset(&set, sig) == -1 && errno == EINVAL) { return false; } return true; #endif } // Returns: // NULL for an invalid signal number // "SIG" for a valid but unknown signal number // signal name otherwise. const char* os::exception_name(int sig, char* buf, size_t size) { if (!os::Posix::is_valid_signal(sig)) { return NULL; } const char* const name = os::Posix::get_signal_name(sig, buf, size); if (strcmp(name, "UNKNOWN") == 0) { jio_snprintf(buf, size, "SIG%d", sig); } return buf; } #define NUM_IMPORTANT_SIGS 32 // Returns one-line short description of a signal set in a user provided buffer. const char* os::Posix::describe_signal_set_short(const sigset_t* set, char* buffer, size_t buf_size) { assert(buf_size == (NUM_IMPORTANT_SIGS + 1), "wrong buffer size"); // Note: for shortness, just print out the first 32. That should // cover most of the useful ones, apart from realtime signals. for (int sig = 1; sig <= NUM_IMPORTANT_SIGS; sig++) { const int rc = sigismember(set, sig); if (rc == -1 && errno == EINVAL) { buffer[sig-1] = '?'; } else { buffer[sig-1] = rc == 0 ? '0' : '1'; } } buffer[NUM_IMPORTANT_SIGS] = 0; return buffer; } // Prints one-line description of a signal set. void os::Posix::print_signal_set_short(outputStream* st, const sigset_t* set) { char buf[NUM_IMPORTANT_SIGS + 1]; os::Posix::describe_signal_set_short(set, buf, sizeof(buf)); st->print("%s", buf); } // Writes one-line description of a combination of sigaction.sa_flags into a user // provided buffer. Returns that buffer. const char* os::Posix::describe_sa_flags(int flags, char* buffer, size_t size) { char* p = buffer; size_t remaining = size; bool first = true; int idx = 0; assert(buffer, "invalid argument"); if (size == 0) { return buffer; } strncpy(buffer, "none", size); const struct { // NB: i is an unsigned int here because SA_RESETHAND is on some // systems 0x80000000, which is implicitly unsigned. Assignining // it to an int field would be an overflow in unsigned-to-signed // conversion. unsigned int i; const char* s; } flaginfo [] = { { SA_NOCLDSTOP, "SA_NOCLDSTOP" }, { SA_ONSTACK, "SA_ONSTACK" }, { SA_RESETHAND, "SA_RESETHAND" }, { SA_RESTART, "SA_RESTART" }, { SA_SIGINFO, "SA_SIGINFO" }, { SA_NOCLDWAIT, "SA_NOCLDWAIT" }, { SA_NODEFER, "SA_NODEFER" }, #ifdef AIX { SA_ONSTACK, "SA_ONSTACK" }, { SA_OLDSTYLE, "SA_OLDSTYLE" }, #endif { 0, NULL } }; for (idx = 0; flaginfo[idx].s && remaining > 1; idx++) { if (flags & flaginfo[idx].i) { if (first) { jio_snprintf(p, remaining, "%s", flaginfo[idx].s); first = false; } else { jio_snprintf(p, remaining, "|%s", flaginfo[idx].s); } const size_t len = strlen(p); p += len; remaining -= len; } } buffer[size - 1] = '\0'; return buffer; } // Prints one-line description of a combination of sigaction.sa_flags. void os::Posix::print_sa_flags(outputStream* st, int flags) { char buffer[0x100]; os::Posix::describe_sa_flags(flags, buffer, sizeof(buffer)); st->print("%s", buffer); } // Helper function for os::Posix::print_siginfo_...(): // return a textual description for signal code. struct enum_sigcode_desc_t { const char* s_name; const char* s_desc; }; static bool get_signal_code_description(const siginfo_t* si, enum_sigcode_desc_t* out) { const struct { int sig; int code; const char* s_code; const char* s_desc; } t1 [] = { { SIGILL, ILL_ILLOPC, "ILL_ILLOPC", "Illegal opcode." }, { SIGILL, ILL_ILLOPN, "ILL_ILLOPN", "Illegal operand." }, { SIGILL, ILL_ILLADR, "ILL_ILLADR", "Illegal addressing mode." }, { SIGILL, ILL_ILLTRP, "ILL_ILLTRP", "Illegal trap." }, { SIGILL, ILL_PRVOPC, "ILL_PRVOPC", "Privileged opcode." }, { SIGILL, ILL_PRVREG, "ILL_PRVREG", "Privileged register." }, { SIGILL, ILL_COPROC, "ILL_COPROC", "Coprocessor error." }, { SIGILL, ILL_BADSTK, "ILL_BADSTK", "Internal stack error." }, #if defined(IA64) && defined(LINUX) { SIGILL, ILL_BADIADDR, "ILL_BADIADDR", "Unimplemented instruction address" }, { SIGILL, ILL_BREAK, "ILL_BREAK", "Application Break instruction" }, #endif { SIGFPE, FPE_INTDIV, "FPE_INTDIV", "Integer divide by zero." }, { SIGFPE, FPE_INTOVF, "FPE_INTOVF", "Integer overflow." }, { SIGFPE, FPE_FLTDIV, "FPE_FLTDIV", "Floating-point divide by zero." }, { SIGFPE, FPE_FLTOVF, "FPE_FLTOVF", "Floating-point overflow." }, { SIGFPE, FPE_FLTUND, "FPE_FLTUND", "Floating-point underflow." }, { SIGFPE, FPE_FLTRES, "FPE_FLTRES", "Floating-point inexact result." }, { SIGFPE, FPE_FLTINV, "FPE_FLTINV", "Invalid floating-point operation." }, { SIGFPE, FPE_FLTSUB, "FPE_FLTSUB", "Subscript out of range." }, { SIGSEGV, SEGV_MAPERR, "SEGV_MAPERR", "Address not mapped to object." }, { SIGSEGV, SEGV_ACCERR, "SEGV_ACCERR", "Invalid permissions for mapped object." }, #ifdef AIX // no explanation found what keyerr would be { SIGSEGV, SEGV_KEYERR, "SEGV_KEYERR", "key error" }, #endif #if defined(IA64) && !defined(AIX) { SIGSEGV, SEGV_PSTKOVF, "SEGV_PSTKOVF", "Paragraph stack overflow" }, #endif #if defined(__sparc) && defined(SOLARIS) // define Solaris Sparc M7 ADI SEGV signals #if !defined(SEGV_ACCADI) #define SEGV_ACCADI 3 #endif { SIGSEGV, SEGV_ACCADI, "SEGV_ACCADI", "ADI not enabled for mapped object." }, #if !defined(SEGV_ACCDERR) #define SEGV_ACCDERR 4 #endif { SIGSEGV, SEGV_ACCDERR, "SEGV_ACCDERR", "ADI disrupting exception." }, #if !defined(SEGV_ACCPERR) #define SEGV_ACCPERR 5 #endif { SIGSEGV, SEGV_ACCPERR, "SEGV_ACCPERR", "ADI precise exception." }, #endif // defined(__sparc) && defined(SOLARIS) { SIGBUS, BUS_ADRALN, "BUS_ADRALN", "Invalid address alignment." }, { SIGBUS, BUS_ADRERR, "BUS_ADRERR", "Nonexistent physical address." }, { SIGBUS, BUS_OBJERR, "BUS_OBJERR", "Object-specific hardware error." }, { SIGTRAP, TRAP_BRKPT, "TRAP_BRKPT", "Process breakpoint." }, { SIGTRAP, TRAP_TRACE, "TRAP_TRACE", "Process trace trap." }, { SIGCHLD, CLD_EXITED, "CLD_EXITED", "Child has exited." }, { SIGCHLD, CLD_KILLED, "CLD_KILLED", "Child has terminated abnormally and did not create a core file." }, { SIGCHLD, CLD_DUMPED, "CLD_DUMPED", "Child has terminated abnormally and created a core file." }, { SIGCHLD, CLD_TRAPPED, "CLD_TRAPPED", "Traced child has trapped." }, { SIGCHLD, CLD_STOPPED, "CLD_STOPPED", "Child has stopped." }, { SIGCHLD, CLD_CONTINUED,"CLD_CONTINUED","Stopped child has continued." }, #ifdef SIGPOLL { SIGPOLL, POLL_OUT, "POLL_OUT", "Output buffers available." }, { SIGPOLL, POLL_MSG, "POLL_MSG", "Input message available." }, { SIGPOLL, POLL_ERR, "POLL_ERR", "I/O error." }, { SIGPOLL, POLL_PRI, "POLL_PRI", "High priority input available." }, { SIGPOLL, POLL_HUP, "POLL_HUP", "Device disconnected. [Option End]" }, #endif { -1, -1, NULL, NULL } }; // Codes valid in any signal context. const struct { int code; const char* s_code; const char* s_desc; } t2 [] = { { SI_USER, "SI_USER", "Signal sent by kill()." }, { SI_QUEUE, "SI_QUEUE", "Signal sent by the sigqueue()." }, { SI_TIMER, "SI_TIMER", "Signal generated by expiration of a timer set by timer_settime()." }, { SI_ASYNCIO, "SI_ASYNCIO", "Signal generated by completion of an asynchronous I/O request." }, { SI_MESGQ, "SI_MESGQ", "Signal generated by arrival of a message on an empty message queue." }, // Linux specific #ifdef SI_TKILL { SI_TKILL, "SI_TKILL", "Signal sent by tkill (pthread_kill)" }, #endif #ifdef SI_DETHREAD { SI_DETHREAD, "SI_DETHREAD", "Signal sent by execve() killing subsidiary threads" }, #endif #ifdef SI_KERNEL { SI_KERNEL, "SI_KERNEL", "Signal sent by kernel." }, #endif #ifdef SI_SIGIO { SI_SIGIO, "SI_SIGIO", "Signal sent by queued SIGIO" }, #endif #ifdef AIX { SI_UNDEFINED, "SI_UNDEFINED","siginfo contains partial information" }, { SI_EMPTY, "SI_EMPTY", "siginfo contains no useful information" }, #endif #ifdef __sun { SI_NOINFO, "SI_NOINFO", "No signal information" }, { SI_RCTL, "SI_RCTL", "kernel generated signal via rctl action" }, { SI_LWP, "SI_LWP", "Signal sent via lwp_kill" }, #endif { -1, NULL, NULL } }; const char* s_code = NULL; const char* s_desc = NULL; for (int i = 0; t1[i].sig != -1; i ++) { if (t1[i].sig == si->si_signo && t1[i].code == si->si_code) { s_code = t1[i].s_code; s_desc = t1[i].s_desc; break; } } if (s_code == NULL) { for (int i = 0; t2[i].s_code != NULL; i ++) { if (t2[i].code == si->si_code) { s_code = t2[i].s_code; s_desc = t2[i].s_desc; } } } if (s_code == NULL) { out->s_name = "unknown"; out->s_desc = "unknown"; return false; } out->s_name = s_code; out->s_desc = s_desc; return true; } void os::print_siginfo(outputStream* os, const void* si0) { const siginfo_t* const si = (const siginfo_t*) si0; char buf[20]; os->print("siginfo:"); if (!si) { os->print(" "); return; } const int sig = si->si_signo; os->print(" si_signo: %d (%s)", sig, os::Posix::get_signal_name(sig, buf, sizeof(buf))); enum_sigcode_desc_t ed; get_signal_code_description(si, &ed); os->print(", si_code: %d (%s)", si->si_code, ed.s_name); if (si->si_errno) { os->print(", si_errno: %d", si->si_errno); } // Output additional information depending on the signal code. // Note: Many implementations lump si_addr, si_pid, si_uid etc. together as unions, // so it depends on the context which member to use. For synchronous error signals, // we print si_addr, unless the signal was sent by another process or thread, in // which case we print out pid or tid of the sender. if (si->si_code == SI_USER || si->si_code == SI_QUEUE) { const pid_t pid = si->si_pid; os->print(", si_pid: %ld", (long) pid); if (IS_VALID_PID(pid)) { const pid_t me = getpid(); if (me == pid) { os->print(" (current process)"); } } else { os->print(" (invalid)"); } os->print(", si_uid: %ld", (long) si->si_uid); if (sig == SIGCHLD) { os->print(", si_status: %d", si->si_status); } } else if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL || sig == SIGTRAP || sig == SIGFPE) { os->print(", si_addr: " PTR_FORMAT, p2i(si->si_addr)); #ifdef SIGPOLL } else if (sig == SIGPOLL) { os->print(", si_band: %ld", si->si_band); #endif } } int os::Posix::unblock_thread_signal_mask(const sigset_t *set) { return pthread_sigmask(SIG_UNBLOCK, set, NULL); } address os::Posix::ucontext_get_pc(const ucontext_t* ctx) { #if defined(AIX) return Aix::ucontext_get_pc(ctx); #elif defined(BSD) return Bsd::ucontext_get_pc(ctx); #elif defined(LINUX) return Linux::ucontext_get_pc(ctx); #elif defined(SOLARIS) return Solaris::ucontext_get_pc(ctx); #else VMError::report_and_die("unimplemented ucontext_get_pc"); #endif } void os::Posix::ucontext_set_pc(ucontext_t* ctx, address pc) { #if defined(AIX) Aix::ucontext_set_pc(ctx, pc); #elif defined(BSD) Bsd::ucontext_set_pc(ctx, pc); #elif defined(LINUX) Linux::ucontext_set_pc(ctx, pc); #elif defined(SOLARIS) Solaris::ucontext_set_pc(ctx, pc); #else VMError::report_and_die("unimplemented ucontext_get_pc"); #endif } char* os::Posix::describe_pthread_attr(char* buf, size_t buflen, const pthread_attr_t* attr) { size_t stack_size = 0; size_t guard_size = 0; int detachstate = 0; pthread_attr_getstacksize(attr, &stack_size); pthread_attr_getguardsize(attr, &guard_size); // Work around linux NPTL implementation error, see also os::create_thread() in os_linux.cpp. LINUX_ONLY(stack_size -= guard_size); pthread_attr_getdetachstate(attr, &detachstate); jio_snprintf(buf, buflen, "stacksize: " SIZE_FORMAT "k, guardsize: " SIZE_FORMAT "k, %s", stack_size / 1024, guard_size / 1024, (detachstate == PTHREAD_CREATE_DETACHED ? "detached" : "joinable")); return buf; } char* os::Posix::realpath(const char* filename, char* outbuf, size_t outbuflen) { if (filename == NULL || outbuf == NULL || outbuflen < 1) { assert(false, "os::Posix::realpath: invalid arguments."); errno = EINVAL; return NULL; } char* result = NULL; // This assumes platform realpath() is implemented according to POSIX.1-2008. // POSIX.1-2008 allows to specify NULL for the output buffer, in which case // output buffer is dynamically allocated and must be ::free()'d by the caller. char* p = ::realpath(filename, NULL); if (p != NULL) { if (strlen(p) < outbuflen) { strcpy(outbuf, p); result = outbuf; } else { errno = ENAMETOOLONG; } ::free(p); // *not* os::free } else { // Fallback for platforms struggling with modern Posix standards (AIX 5.3, 6.1). If realpath // returns EINVAL, this may indicate that realpath is not POSIX.1-2008 compatible and // that it complains about the NULL we handed down as user buffer. // In this case, use the user provided buffer but at least check whether realpath caused // a memory overwrite. if (errno == EINVAL) { outbuf[outbuflen - 1] = '\0'; p = ::realpath(filename, outbuf); if (p != NULL) { guarantee(outbuf[outbuflen - 1] == '\0', "realpath buffer overwrite detected."); result = p; } } } return result; } // Check minimum allowable stack sizes for thread creation and to initialize // the java system classes, including StackOverflowError - depends on page // size. // The space needed for frames during startup is platform dependent. It // depends on word size, platform calling conventions, C frame layout and // interpreter/C1/C2 design decisions. Therefore this is given in a // platform (os/cpu) dependent constant. // To this, space for guard mechanisms is added, which depends on the // page size which again depends on the concrete system the VM is running // on. Space for libc guard pages is not included in this size. jint os::Posix::set_minimum_stack_sizes() { size_t os_min_stack_allowed = SOLARIS_ONLY(thr_min_stack()) NOT_SOLARIS(PTHREAD_STACK_MIN); _java_thread_min_stack_allowed = _java_thread_min_stack_allowed + JavaThread::stack_guard_zone_size() + JavaThread::stack_shadow_zone_size(); _java_thread_min_stack_allowed = align_up(_java_thread_min_stack_allowed, vm_page_size()); _java_thread_min_stack_allowed = MAX2(_java_thread_min_stack_allowed, os_min_stack_allowed); size_t stack_size_in_bytes = ThreadStackSize * K; if (stack_size_in_bytes != 0 && stack_size_in_bytes < _java_thread_min_stack_allowed) { // The '-Xss' and '-XX:ThreadStackSize=N' options both set // ThreadStackSize so we go with "Java thread stack size" instead // of "ThreadStackSize" to be more friendly. tty->print_cr("\nThe Java thread stack size specified is too small. " "Specify at least " SIZE_FORMAT "k", _java_thread_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(align_up(stack_size_in_bytes, vm_page_size())); // Reminder: a compiler thread is a Java thread. _compiler_thread_min_stack_allowed = _compiler_thread_min_stack_allowed + JavaThread::stack_guard_zone_size() + JavaThread::stack_shadow_zone_size(); _compiler_thread_min_stack_allowed = align_up(_compiler_thread_min_stack_allowed, vm_page_size()); _compiler_thread_min_stack_allowed = MAX2(_compiler_thread_min_stack_allowed, os_min_stack_allowed); stack_size_in_bytes = CompilerThreadStackSize * K; if (stack_size_in_bytes != 0 && stack_size_in_bytes < _compiler_thread_min_stack_allowed) { tty->print_cr("\nThe CompilerThreadStackSize specified is too small. " "Specify at least " SIZE_FORMAT "k", _compiler_thread_min_stack_allowed / K); return JNI_ERR; } _vm_internal_thread_min_stack_allowed = align_up(_vm_internal_thread_min_stack_allowed, vm_page_size()); _vm_internal_thread_min_stack_allowed = MAX2(_vm_internal_thread_min_stack_allowed, os_min_stack_allowed); stack_size_in_bytes = VMThreadStackSize * K; if (stack_size_in_bytes != 0 && stack_size_in_bytes < _vm_internal_thread_min_stack_allowed) { tty->print_cr("\nThe VMThreadStackSize specified is too small. " "Specify at least " SIZE_FORMAT "k", _vm_internal_thread_min_stack_allowed / K); return JNI_ERR; } return JNI_OK; } // Called when creating the thread. The minimum stack sizes have already been calculated size_t os::Posix::get_initial_stack_size(ThreadType thr_type, size_t req_stack_size) { size_t stack_size; if (req_stack_size == 0) { stack_size = default_stack_size(thr_type); } else { stack_size = req_stack_size; } switch (thr_type) { case os::java_thread: // Java threads use ThreadStackSize which default value can be // changed with the flag -Xss if (req_stack_size == 0 && JavaThread::stack_size_at_create() > 0) { // no requested size and we have a more specific default value stack_size = JavaThread::stack_size_at_create(); } stack_size = MAX2(stack_size, _java_thread_min_stack_allowed); break; case os::compiler_thread: if (req_stack_size == 0 && CompilerThreadStackSize > 0) { // no requested size and we have a more specific default value stack_size = (size_t)(CompilerThreadStackSize * K); } stack_size = MAX2(stack_size, _compiler_thread_min_stack_allowed); break; case os::vm_thread: case os::pgc_thread: case os::cgc_thread: case os::watcher_thread: default: // presume the unknown thr_type is a VM internal if (req_stack_size == 0 && VMThreadStackSize > 0) { // no requested size and we have a more specific default value stack_size = (size_t)(VMThreadStackSize * K); } stack_size = MAX2(stack_size, _vm_internal_thread_min_stack_allowed); break; } // pthread_attr_setstacksize() may require that the size be rounded up to the OS page size. // Be careful not to round up to 0. Align down in that case. if (stack_size <= SIZE_MAX - vm_page_size()) { stack_size = align_up(stack_size, vm_page_size()); } else { stack_size = align_down(stack_size, vm_page_size()); } return stack_size; } Thread* os::ThreadCrashProtection::_protected_thread = NULL; os::ThreadCrashProtection* os::ThreadCrashProtection::_crash_protection = NULL; volatile intptr_t os::ThreadCrashProtection::_crash_mux = 0; os::ThreadCrashProtection::ThreadCrashProtection() { } /* * See the caveats for this class in os_posix.hpp * Protects the callback call so that SIGSEGV / SIGBUS jumps back into this * method and returns false. If none of the signals are raised, returns true. * The callback is supposed to provide the method that should be protected. */ bool os::ThreadCrashProtection::call(os::CrashProtectionCallback& cb) { sigset_t saved_sig_mask; Thread::muxAcquire(&_crash_mux, "CrashProtection"); _protected_thread = Thread::current_or_null(); assert(_protected_thread != NULL, "Cannot crash protect a NULL thread"); // we cannot rely on sigsetjmp/siglongjmp to save/restore the signal mask // since on at least some systems (OS X) siglongjmp will restore the mask // for the process, not the thread pthread_sigmask(0, NULL, &saved_sig_mask); if (sigsetjmp(_jmpbuf, 0) == 0) { // make sure we can see in the signal handler that we have crash protection // installed _crash_protection = this; cb.call(); // and clear the crash protection _crash_protection = NULL; _protected_thread = NULL; Thread::muxRelease(&_crash_mux); return true; } // this happens when we siglongjmp() back pthread_sigmask(SIG_SETMASK, &saved_sig_mask, NULL); _crash_protection = NULL; _protected_thread = NULL; Thread::muxRelease(&_crash_mux); return false; } void os::ThreadCrashProtection::restore() { assert(_crash_protection != NULL, "must have crash protection"); siglongjmp(_jmpbuf, 1); } void os::ThreadCrashProtection::check_crash_protection(int sig, Thread* thread) { if (thread != NULL && thread == _protected_thread && _crash_protection != NULL) { if (sig == SIGSEGV || sig == SIGBUS) { _crash_protection->restore(); } } } // POSIX unamed semaphores are not supported on OS X. #ifndef __APPLE__ PosixSemaphore::PosixSemaphore(uint value) { int ret = sem_init(&_semaphore, 0, value); guarantee_with_errno(ret == 0, "Failed to initialize semaphore"); } PosixSemaphore::~PosixSemaphore() { sem_destroy(&_semaphore); } void PosixSemaphore::signal(uint count) { for (uint i = 0; i < count; i++) { int ret = sem_post(&_semaphore); assert_with_errno(ret == 0, "sem_post failed"); } } void PosixSemaphore::wait() { int ret; do { ret = sem_wait(&_semaphore); } while (ret != 0 && errno == EINTR); assert_with_errno(ret == 0, "sem_wait failed"); } bool PosixSemaphore::trywait() { int ret; do { ret = sem_trywait(&_semaphore); } while (ret != 0 && errno == EINTR); assert_with_errno(ret == 0 || errno == EAGAIN, "trywait failed"); return ret == 0; } bool PosixSemaphore::timedwait(struct timespec ts) { while (true) { int result = sem_timedwait(&_semaphore, &ts); if (result == 0) { return true; } else if (errno == EINTR) { continue; } else if (errno == ETIMEDOUT) { return false; } else { assert_with_errno(false, "timedwait failed"); return false; } } } #endif // __APPLE__ // Shared pthread_mutex/cond based PlatformEvent implementation. // Not currently usable by Solaris. #ifndef SOLARIS // Shared condattr object for use with relative timed-waits. Will be associated // with CLOCK_MONOTONIC if available to avoid issues with time-of-day changes, // but otherwise whatever default is used by the platform - generally the // time-of-day clock. static pthread_condattr_t _condAttr[1]; // Shared mutexattr to explicitly set the type to PTHREAD_MUTEX_NORMAL as not // all systems (e.g. FreeBSD) map the default to "normal". static pthread_mutexattr_t _mutexAttr[1]; // common basic initialization that is always supported static void pthread_init_common(void) { int status; if ((status = pthread_condattr_init(_condAttr)) != 0) { fatal("pthread_condattr_init: %s", os::strerror(status)); } if ((status = pthread_mutexattr_init(_mutexAttr)) != 0) { fatal("pthread_mutexattr_init: %s", os::strerror(status)); } if ((status = pthread_mutexattr_settype(_mutexAttr, PTHREAD_MUTEX_NORMAL)) != 0) { fatal("pthread_mutexattr_settype: %s", os::strerror(status)); } } // Not all POSIX types and API's are available on all notionally "posix" // platforms. If we have build-time support then we will check for actual // runtime support via dlopen/dlsym lookup. This allows for running on an // older OS version compared to the build platform. But if there is no // build time support then there cannot be any runtime support as we do not // know what the runtime types would be (for example clockid_t might be an // int or int64_t). // #ifdef SUPPORTS_CLOCK_MONOTONIC // This means we have clockid_t, clock_gettime et al and CLOCK_MONOTONIC static int (*_clock_gettime)(clockid_t, struct timespec *); static int (*_pthread_condattr_setclock)(pthread_condattr_t *, clockid_t); static bool _use_clock_monotonic_condattr; // Determine what POSIX API's are present and do appropriate // configuration. void os::Posix::init(void) { // NOTE: no logging available when this is called. Put logging // statements in init_2(). // Copied from os::Linux::clock_init(). The duplication is temporary. // 1. Check for CLOCK_MONOTONIC support. void* handle = NULL; // For linux we need librt, for other OS we can find // this function in regular libc. #ifdef NEEDS_LIBRT // We do dlopen's in this particular order due to bug in linux // dynamic loader (see 6348968) leading to crash on exit. handle = dlopen("librt.so.1", RTLD_LAZY); if (handle == NULL) { handle = dlopen("librt.so", RTLD_LAZY); } #endif if (handle == NULL) { handle = RTLD_DEFAULT; } _clock_gettime = NULL; 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 != NULL && clock_gettime_func != NULL) { // We assume that if both clock_gettime and clock_getres support // CLOCK_MONOTONIC then the OS provides true high-res monotonic clock. 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 { #ifdef NEEDS_LIBRT // Close librt if there is no monotonic clock. if (handle != RTLD_DEFAULT) { dlclose(handle); } #endif } } // 2. Check for pthread_condattr_setclock support. _pthread_condattr_setclock = NULL; // libpthread is already loaded. int (*condattr_setclock_func)(pthread_condattr_t*, clockid_t) = (int (*)(pthread_condattr_t*, clockid_t))dlsym(RTLD_DEFAULT, "pthread_condattr_setclock"); if (condattr_setclock_func != NULL) { _pthread_condattr_setclock = condattr_setclock_func; } // Now do general initialization. pthread_init_common(); int status; if (_pthread_condattr_setclock != NULL && _clock_gettime != NULL) { if ((status = _pthread_condattr_setclock(_condAttr, CLOCK_MONOTONIC)) != 0) { if (status == EINVAL) { _use_clock_monotonic_condattr = false; warning("Unable to use monotonic clock with relative timed-waits" \ " - changes to the time-of-day clock may have adverse affects"); } else { fatal("pthread_condattr_setclock: %s", os::strerror(status)); } } else { _use_clock_monotonic_condattr = true; } } else { _use_clock_monotonic_condattr = false; } } void os::Posix::init_2(void) { log_info(os)("Use of CLOCK_MONOTONIC is%s supported", (_clock_gettime != NULL ? "" : " not")); log_info(os)("Use of pthread_condattr_setclock is%s supported", (_pthread_condattr_setclock != NULL ? "" : " not")); log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with %s", _use_clock_monotonic_condattr ? "CLOCK_MONOTONIC" : "the default clock"); } #else // !SUPPORTS_CLOCK_MONOTONIC void os::Posix::init(void) { pthread_init_common(); } void os::Posix::init_2(void) { log_info(os)("Use of CLOCK_MONOTONIC is not supported"); log_info(os)("Use of pthread_condattr_setclock is not supported"); log_info(os)("Relative timed-wait using pthread_cond_timedwait is associated with the default clock"); } #endif // SUPPORTS_CLOCK_MONOTONIC os::PlatformEvent::PlatformEvent() { int status = pthread_cond_init(_cond, _condAttr); assert_status(status == 0, status, "cond_init"); status = pthread_mutex_init(_mutex, _mutexAttr); assert_status(status == 0, status, "mutex_init"); _event = 0; _nParked = 0; } // Utility to convert the given timeout to an absolute timespec // (based on the appropriate clock) to use with pthread_cond_timewait. // The clock queried here must be the clock used to manage the // timeout of the condition variable. // // The passed in timeout value is either a relative time in nanoseconds // or an absolute time in milliseconds. A relative timeout will be // associated with CLOCK_MONOTONIC if available; otherwise, or if absolute, // the default time-of-day clock will be used. // Given time is a 64-bit value and the time_t used in the timespec is // sometimes a signed-32-bit value 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 + 100000000. // As it will be over 20 years before "now + 100000000" will overflow we can // ignore overflow and just impose a hard-limit on seconds using the value // of "now + 100000000". This places a limit on the timeout of about 3.17 // years from "now". // #define MAX_SECS 100000000 // Calculate a new absolute time that is "timeout" nanoseconds from "now". // "unit" indicates the unit of "now_part_sec" (may be nanos or micros depending // on which clock is being used). static void calc_rel_time(timespec* abstime, jlong timeout, jlong now_sec, jlong now_part_sec, jlong unit) { time_t max_secs = now_sec + MAX_SECS; jlong seconds = timeout / NANOUNITS; timeout %= NANOUNITS; // remaining nanos if (seconds >= MAX_SECS) { // More seconds than we can add, so pin to max_secs. abstime->tv_sec = max_secs; abstime->tv_nsec = 0; } else { abstime->tv_sec = now_sec + seconds; long nanos = (now_part_sec * (NANOUNITS / unit)) + timeout; if (nanos >= NANOUNITS) { // overflow abstime->tv_sec += 1; nanos -= NANOUNITS; } abstime->tv_nsec = nanos; } } // Unpack the given deadline in milliseconds since the epoch, into the given timespec. // The current time in seconds is also passed in to enforce an upper bound as discussed above. static void unpack_abs_time(timespec* abstime, jlong deadline, jlong now_sec) { time_t max_secs = now_sec + MAX_SECS; jlong seconds = deadline / MILLIUNITS; jlong millis = deadline % MILLIUNITS; if (seconds >= max_secs) { // Absolute seconds exceeds allowed max, so pin to max_secs. abstime->tv_sec = max_secs; abstime->tv_nsec = 0; } else { abstime->tv_sec = seconds; abstime->tv_nsec = millis * (NANOUNITS / MILLIUNITS); } } static void to_abstime(timespec* abstime, jlong timeout, bool isAbsolute) { DEBUG_ONLY(int max_secs = MAX_SECS;) if (timeout < 0) { timeout = 0; } #ifdef SUPPORTS_CLOCK_MONOTONIC if (_use_clock_monotonic_condattr && !isAbsolute) { struct timespec now; int status = _clock_gettime(CLOCK_MONOTONIC, &now); assert_status(status == 0, status, "clock_gettime"); calc_rel_time(abstime, timeout, now.tv_sec, now.tv_nsec, NANOUNITS); DEBUG_ONLY(max_secs += now.tv_sec;) } else { #else { // Match the block scope. #endif // SUPPORTS_CLOCK_MONOTONIC // Time-of-day clock is all we can reliably use. struct timeval now; int status = gettimeofday(&now, NULL); assert_status(status == 0, errno, "gettimeofday"); if (isAbsolute) { unpack_abs_time(abstime, timeout, now.tv_sec); } else { calc_rel_time(abstime, timeout, now.tv_sec, now.tv_usec, MICROUNITS); } DEBUG_ONLY(max_secs += now.tv_sec;) } 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 < NANOUNITS, "tv_nsec >= NANOUNITS"); } // PlatformEvent // // Assumption: // Only one parker can exist on an event, which is why we allocate // them per-thread. Multiple unparkers can coexist. // // _event serves as a restricted-range semaphore. // -1 : thread is blocked, i.e. there is a waiter // 0 : neutral: thread is running or ready, // could have been signaled after a wait started // 1 : signaled - thread is running or ready // // Having three states allows for some detection of bad usage - see // comments on unpark(). void os::PlatformEvent::park() { // AKA "down()" // Transitions for _event: // -1 => -1 : illegal // 1 => 0 : pass - return immediately // 0 => -1 : block; then set _event to 0 before returning // Invariant: Only the thread associated with the PlatformEvent // may call park(). assert(_nParked == 0, "invariant"); int v; // atomically decrement _event 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) { // OS-level "spurious wakeups" are ignored status = pthread_cond_wait(_cond, _mutex); assert_status(status == 0, status, "cond_wait"); } --_nParked; _event = 0; status = pthread_mutex_unlock(_mutex); assert_status(status == 0, status, "mutex_unlock"); // Paranoia to ensure our locked and lock-free paths interact // correctly with each other. OrderAccess::fence(); } guarantee(_event >= 0, "invariant"); } int os::PlatformEvent::park(jlong millis) { // Transitions for _event: // -1 => -1 : illegal // 1 => 0 : pass - return immediately // 0 => -1 : block; then set _event to 0 before returning // Invariant: Only the thread associated with the Event/PlatformEvent // may call park(). assert(_nParked == 0, "invariant"); int v; // atomically decrement _event 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 ... struct timespec abst; // We have to watch for overflow when converting millis to nanos, // but if millis is that large then we will end up limiting to // MAX_SECS anyway, so just do that here. if (millis / MILLIUNITS > MAX_SECS) { millis = jlong(MAX_SECS) * MILLIUNITS; } to_abstime(&abst, millis * (NANOUNITS / MILLIUNITS), false); int ret = OS_TIMEOUT; int status = pthread_mutex_lock(_mutex); assert_status(status == 0, status, "mutex_lock"); guarantee(_nParked == 0, "invariant"); ++_nParked; while (_event < 0) { status = pthread_cond_timedwait(_cond, _mutex, &abst); assert_status(status == 0 || status == ETIMEDOUT, status, "cond_timedwait"); // OS-level "spurious wakeups" are ignored unless the archaic // FilterSpuriousWakeups is set false. That flag should be obsoleted. if (!FilterSpuriousWakeups) break; if (status == ETIMEDOUT) break; } --_nParked; if (_event >= 0) { ret = OS_OK; } _event = 0; status = pthread_mutex_unlock(_mutex); assert_status(status == 0, status, "mutex_unlock"); // Paranoia to ensure our locked and lock-free paths interact // correctly with each other. OrderAccess::fence(); return ret; } return OS_OK; } void os::PlatformEvent::unpark() { // Transitions for _event: // 0 => 1 : just return // 1 => 1 : just return // -1 => either 0 or 1; must signal target thread // That is, we can safely transition _event from -1 to either // 0 or 1. // See also: "Semaphores in Plan 9" by Mullender & Cox // // Note: Forcing a transition from "-1" to "1" on an unpark() means // that it will take two back-to-back park() calls for the owning // thread to block. This has the benefit of forcing a spurious return // from the first park() call after an unpark() call which will help // shake out uses of park() and unpark() without checking state conditions // properly. This spurious return doesn't manifest itself in any user code // but only in the correctly written condition checking loops of ObjectMonitor, // Mutex/Monitor, Thread::muxAcquire and os::sleep if (Atomic::xchg(1, &_event) >= 0) return; int status = pthread_mutex_lock(_mutex); assert_status(status == 0, status, "mutex_lock"); int anyWaiters = _nParked; assert(anyWaiters == 0 || anyWaiters == 1, "invariant"); status = pthread_mutex_unlock(_mutex); assert_status(status == 0, status, "mutex_unlock"); // 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. // This provides particular benefit if the underlying platform does not // provide wait morphing. if (anyWaiters != 0) { status = pthread_cond_signal(_cond); assert_status(status == 0, status, "cond_signal"); } } // JSR166 support os::PlatformParker::PlatformParker() { int status; status = pthread_cond_init(&_cond[REL_INDEX], _condAttr); assert_status(status == 0, status, "cond_init rel"); status = pthread_cond_init(&_cond[ABS_INDEX], NULL); assert_status(status == 0, status, "cond_init abs"); status = pthread_mutex_init(_mutex, _mutexAttr); assert_status(status == 0, status, "mutex_init"); _cur_index = -1; // mark as unused } // Parker::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. void Parker::park(bool isAbsolute, jlong time) { // Optional fast-path check: // Return immediately if a permit is available. // We depend on Atomic::xchg() having full barrier semantics // since we are doing a lock-free update to _counter. if (Atomic::xchg(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. if (Thread::is_interrupted(thread, false)) { return; } // Next, demultiplex/decode time arguments struct timespec absTime; if (time < 0 || (isAbsolute && time == 0)) { // don't wait at all return; } if (time > 0) { to_abstime(&absTime, time, isAbsolute); } // 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 // unparking. Also re-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(status == 0, status, "invariant"); // Paranoia to ensure our locked and lock-free paths interact // correctly with each other and Java-level accesses. OrderAccess::fence(); return; } OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */); jt->set_suspend_equivalent(); // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self() assert(_cur_index == -1, "invariant"); if (time == 0) { _cur_index = REL_INDEX; // arbitrary choice when not timed status = pthread_cond_wait(&_cond[_cur_index], _mutex); assert_status(status == 0, status, "cond_timedwait"); } else { _cur_index = isAbsolute ? ABS_INDEX : REL_INDEX; status = pthread_cond_timedwait(&_cond[_cur_index], _mutex, &absTime); assert_status(status == 0 || status == ETIMEDOUT, status, "cond_timedwait"); } _cur_index = -1; _counter = 0; status = pthread_mutex_unlock(_mutex); assert_status(status == 0, status, "invariant"); // Paranoia to ensure our locked and lock-free paths interact // correctly with each other and Java-level accesses. OrderAccess::fence(); // If externally suspended while waiting, re-suspend if (jt->handle_special_suspend_equivalent_condition()) { jt->java_suspend_self(); } } void Parker::unpark() { int status = pthread_mutex_lock(_mutex); assert_status(status == 0, status, "invariant"); const int s = _counter; _counter = 1; // must capture correct index before unlocking int index = _cur_index; status = pthread_mutex_unlock(_mutex); assert_status(status == 0, status, "invariant"); // 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. // This provides particular benefit if the underlying platform does not // provide wait morphing. if (s < 1 && index != -1) { // thread is definitely parked status = pthread_cond_signal(&_cond[index]); assert_status(status == 0, status, "invariant"); } } #endif // !SOLARIS