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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "pthread_internal.h"
#include <errno.h>
#include <semaphore.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <async_safe/log.h>
#include <bionic/reserved_signals.h>
#include "private/ErrnoRestorer.h"
#include "private/ScopedRWLock.h"
#include "private/bionic_futex.h"
#include "private/bionic_tls.h"
static pthread_internal_t* g_thread_list = nullptr;
static pthread_rwlock_t g_thread_list_lock = PTHREAD_RWLOCK_INITIALIZER;
pthread_t __pthread_internal_add(pthread_internal_t* thread) {
ScopedWriteLock locker(&g_thread_list_lock);
// We insert at the head.
thread->next = g_thread_list;
thread->prev = nullptr;
if (thread->next != nullptr) {
thread->next->prev = thread;
}
g_thread_list = thread;
return reinterpret_cast<pthread_t>(thread);
}
void __pthread_internal_remove(pthread_internal_t* thread) {
ScopedWriteLock locker(&g_thread_list_lock);
if (thread->next != nullptr) {
thread->next->prev = thread->prev;
}
if (thread->prev != nullptr) {
thread->prev->next = thread->next;
} else {
g_thread_list = thread->next;
}
}
static void __pthread_internal_free(pthread_internal_t* thread) {
if (thread->mmap_size != 0) {
// Free mapped space, including thread stack and pthread_internal_t.
munmap(thread->mmap_base, thread->mmap_size);
}
}
void __pthread_internal_remove_and_free(pthread_internal_t* thread) {
__pthread_internal_remove(thread);
__pthread_internal_free(thread);
}
pid_t __pthread_internal_gettid(pthread_t thread_id, const char* caller) {
pthread_internal_t* thread = __pthread_internal_find(thread_id, caller);
return thread ? thread->tid : -1;
}
pthread_internal_t* __pthread_internal_find(pthread_t thread_id, const char* caller) {
pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(thread_id);
// Check if we're looking for ourselves before acquiring the lock.
if (thread == __get_thread()) return thread;
{
// Make sure to release the lock before the abort below. Otherwise,
// some apps might deadlock in their own crash handlers (see b/6565627).
ScopedReadLock locker(&g_thread_list_lock);
for (pthread_internal_t* t = g_thread_list; t != nullptr; t = t->next) {
if (t == thread) return thread;
}
}
// Historically we'd return null, but from API level 26 we catch this error.
if (android_get_application_target_sdk_version() >= 26) {
if (thread == nullptr) {
// This seems to be a common mistake, and it's relatively harmless because
// there will never be a valid thread at address 0, whereas other invalid
// addresses might sometimes contain threads or things that look enough like
// threads for us to do some real damage by continuing.
// TODO: try getting rid of this when Treble lets us keep vendor blobs on an old API level.
async_safe_format_log(ANDROID_LOG_WARN, "libc", "invalid pthread_t (0) passed to %s", caller);
} else {
async_safe_fatal("invalid pthread_t %p passed to %s", thread, caller);
}
}
return nullptr;
}
bool android_run_on_all_threads(bool (*func)(void*), void* arg) {
// Take the locks in this order to avoid inversion (pthread_create ->
// __pthread_internal_add).
ScopedWriteLock creation_locker(&g_thread_creation_lock);
ScopedReadLock list_locker(&g_thread_list_lock);
// Call the function directly for the current thread so that we don't need to worry about
// the consequences of synchronizing with ourselves.
if (!func(arg)) {
return false;
}
static sem_t g_sem;
if (sem_init(&g_sem, 0, 0) != 0) {
return false;
}
static bool (*g_func)(void*);
static void *g_arg;
g_func = func;
g_arg = arg;
static _Atomic(bool) g_retval;
atomic_init(&g_retval, true);
auto handler = [](int, siginfo_t*, void*) {
ErrnoRestorer restorer;
if (!g_func(g_arg)) {
atomic_store(&g_retval, false);
}
sem_post(&g_sem);
};
struct sigaction act = {}, oldact;
act.sa_flags = SA_SIGINFO;
act.sa_sigaction = handler;
sigfillset(&act.sa_mask);
if (sigaction(BIONIC_SIGNAL_RUN_ON_ALL_THREADS, &act, &oldact) != 0) {
sem_destroy(&g_sem);
return false;
}
pid_t my_pid = getpid();
size_t num_tids = 0;
for (pthread_internal_t* t = g_thread_list; t != nullptr; t = t->next) {
// The function is called directly for the current thread above, so no need to send a signal to
// ourselves to call it here.
if (t == __get_thread()) continue;
// If a thread is terminating (has blocked signals) or has already terminated, our signal will
// never be received, so we need to check for that condition and skip the thread if it is the
// case.
if (atomic_load(&t->terminating)) continue;
if (tgkill(my_pid, t->tid, BIONIC_SIGNAL_RUN_ON_ALL_THREADS) == 0) {
++num_tids;
} else {
atomic_store(&g_retval, false);
}
}
for (size_t i = 0; i != num_tids; ++i) {
if (TEMP_FAILURE_RETRY(sem_wait(&g_sem)) != 0) {
atomic_store(&g_retval, false);
break;
}
}
sigaction(BIONIC_SIGNAL_RUN_ON_ALL_THREADS, &oldact, 0);
sem_destroy(&g_sem);
return atomic_load(&g_retval);
}
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