6546236: Thread interrupt() of Thread.sleep() can be lost on Solaris due to race with signal handler
Reviewed-by: dholmes, dcubed
/*
* Copyright (c) 1999, 2014, 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 "prims/jvm.h"
#include "runtime/frame.inline.hpp"
#include "runtime/interfaceSupport.hpp"
#include "runtime/os.hpp"
#include "utilities/vmError.hpp"
#include <unistd.h>
#include <sys/resource.h>
#include <sys/utsname.h>
#include <pthread.h>
#include <signal.h>
// Check core dump limit and report possible place where core can be found
void os::check_or_create_dump(void* exceptionRecord, void* contextRecord, char* buffer, size_t bufferSize) {
int n;
struct rlimit rlim;
bool success;
n = get_core_path(buffer, bufferSize);
if (getrlimit(RLIMIT_CORE, &rlim) != 0) {
jio_snprintf(buffer + n, bufferSize - n, "/core or core.%d (may not exist)", current_process_id());
success = true;
} else {
switch(rlim.rlim_cur) {
case RLIM_INFINITY:
jio_snprintf(buffer + n, bufferSize - n, "/core or core.%d", current_process_id());
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 + n, bufferSize - n, "/core or core.%d (max size %lu kB). To ensure a full core dump, try \"ulimit -c unlimited\" before starting Java again", current_process_id(), (unsigned long)(rlim.rlim_cur >> 10));
success = true;
break;
}
}
VMError::report_coredump_status(buffer, success);
}
address os::get_caller_pc(int n) {
#ifdef _NMT_NOINLINE_
n ++;
#endif
frame fr = os::current_frame();
while (n > 0 && fr.pc() &&
!os::is_first_C_frame(&fr) && fr.sender_pc()) {
fr = os::get_sender_for_C_frame(&fr);
n --;
}
if (n == 0) {
return fr.pc();
} else {
return NULL;
}
}
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;
}
// 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) {
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 = os::reserve_memory(extra_size, NULL, alignment);
if (extra_base == NULL) {
return NULL;
}
// Do manual alignment
char* aligned_base = (char*) align_size_up((uintptr_t) 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);
}
return aligned_base;
}
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("%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);
//Isn't there on solaris
#ifndef TARGET_OS_FAMILY_solaris
st->print(", NPROC ");
getrlimit(RLIMIT_NPROC, &rlim);
if (rlim.rlim_cur == RLIM_INFINITY) st->print("infinity");
else st->print("%d", rlim.rlim_cur);
#endif
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();
}
void os::Posix::print_uname_info(outputStream* st) {
// 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();
}
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_size_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);
}
// Builds a platform dependent Agent_OnLoad_<lib_name> 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) {
len = 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 (len <= (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;
}
os::WatcherThreadCrashProtection::WatcherThreadCrashProtection() {
assert(Thread::current()->is_Watcher_thread(), "Must be WatcherThread");
}
/*
* 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::WatcherThreadCrashProtection::call(os::CrashProtectionCallback& cb) {
sigset_t saved_sig_mask;
assert(Thread::current()->is_Watcher_thread(), "Only for WatcherThread");
assert(!WatcherThread::watcher_thread()->has_crash_protection(),
"crash_protection already set?");
// 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
WatcherThread::watcher_thread()->set_crash_protection(this);
cb.call();
// and clear the crash protection
WatcherThread::watcher_thread()->set_crash_protection(NULL);
return true;
}
// this happens when we siglongjmp() back
pthread_sigmask(SIG_SETMASK, &saved_sig_mask, NULL);
WatcherThread::watcher_thread()->set_crash_protection(NULL);
return false;
}
void os::WatcherThreadCrashProtection::restore() {
assert(WatcherThread::watcher_thread()->has_crash_protection(),
"must have crash protection");
siglongjmp(_jmpbuf, 1);
}
void os::WatcherThreadCrashProtection::check_crash_protection(int sig,
Thread* thread) {
if (thread != NULL &&
thread->is_Watcher_thread() &&
WatcherThread::watcher_thread()->has_crash_protection()) {
if (sig == SIGSEGV || sig == SIGBUS) {
WatcherThread::watcher_thread()->crash_protection()->restore();
}
}
}