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Merge "Clean up pthread_create."

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This commit is contained in:
Elliott Hughes 2013-02-13 01:56:46 +00:00 committed by Gerrit Code Review
commit 07f7e62a25
3 changed files with 235 additions and 232 deletions
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3
libc/Android.mk
View File

@ -409,6 +409,7 @@ libc_common_src_files += \
libc_static_common_src_files += \
bionic/pthread.c.arm \
bionic/pthread_create.cpp.arm \
bionic/pthread_key.cpp.arm \
# these are used by the static and dynamic versions of the libc
@ -450,6 +451,7 @@ libc_common_src_files += \
libc_static_common_src_files += \
bionic/pthread.c \
bionic/pthread_create.cpp \
bionic/pthread_key.cpp \
libc_arch_static_src_files := \
@ -497,6 +499,7 @@ libc_common_src_files += \
libc_static_common_src_files += \
bionic/pthread.c \
bionic/pthread_create.cpp \
bionic/pthread_key.cpp \
libc_arch_static_src_files := \

232
libc/bionic/pthread.c
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@ -31,7 +31,6 @@
#include <errno.h>
#include <limits.h>
#include <sys/atomics.h>
#include <sys/mman.h>
#include <unistd.h>
#include "bionic_atomic_inline.h"
@ -39,14 +38,12 @@
#include "bionic_pthread.h"
#include "bionic_ssp.h"
#include "bionic_tls.h"
#include "debug_format.h"
#include "pthread_internal.h"
#include "thread_private.h"
extern void pthread_debug_mutex_lock_check(pthread_mutex_t *mutex);
extern void pthread_debug_mutex_unlock_check(pthread_mutex_t *mutex);
extern int __pthread_clone(int (*fn)(void*), void *child_stack, int flags, void *arg);
extern void _exit_with_stack_teardown(void * stackBase, int stackSize, int retCode);
extern void _exit_thread(int retCode);
@ -63,21 +60,8 @@ int __futex_wait_ex(volatile void *ftx, int pshared, int val, const struct time
#define __likely(cond) __builtin_expect(!!(cond), 1)
#define __unlikely(cond) __builtin_expect(!!(cond), 0)
#ifdef __i386__
#define ATTRIBUTES __attribute__((noinline)) __attribute__((fastcall))
#else
#define ATTRIBUTES __attribute__((noinline))
#endif
void ATTRIBUTES _thread_created_hook(pid_t thread_id);
static const int kPthreadInitFailed = 1;
static pthread_mutex_t mmap_lock = PTHREAD_MUTEX_INITIALIZER;
__LIBC_HIDDEN__ pthread_internal_t* gThreadList = NULL;
__LIBC_HIDDEN__ pthread_mutex_t gThreadListLock = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t gDebuggerNotificationLock = PTHREAD_MUTEX_INITIALIZER;
static void _pthread_internal_remove_locked(pthread_internal_t* thread) {
if (thread->next != NULL) {
@ -135,222 +119,6 @@ __get_stack_base(int *p_stack_size)
}
void __init_tls(void** tls, void* thread) {
((pthread_internal_t*) thread)->tls = tls;
// Zero-initialize all the slots.
for (size_t i = 0; i < BIONIC_TLS_SLOTS; ++i) {
tls[i] = NULL;
}
// Slot 0 must point to itself. The x86 Linux kernel reads the TLS from %fs:0.
tls[TLS_SLOT_SELF] = tls;
tls[TLS_SLOT_THREAD_ID] = thread;
// GCC looks in the TLS for the stack guard on x86, so copy it there from our global.
tls[TLS_SLOT_STACK_GUARD] = (void*) __stack_chk_guard;
__set_tls((void*) tls);
}
/*
* This trampoline is called from the assembly _pthread_clone() function.
*/
void __thread_entry(int (*func)(void*), void *arg, void **tls)
{
// Wait for our creating thread to release us. This lets it have time to
// notify gdb about this thread before we start doing anything.
//
// This also provides the memory barrier needed to ensure that all memory
// accesses previously made by the creating thread are visible to us.
pthread_mutex_t* start_mutex = (pthread_mutex_t*) &tls[TLS_SLOT_SELF];
pthread_mutex_lock(start_mutex);
pthread_mutex_destroy(start_mutex);
pthread_internal_t* thread = (pthread_internal_t*) tls[TLS_SLOT_THREAD_ID];
__init_tls(tls, thread);
if ((thread->internal_flags & kPthreadInitFailed) != 0) {
pthread_exit(NULL);
}
int result = func(arg);
pthread_exit((void*) result);
}
#include <private/logd.h>
__LIBC_ABI_PRIVATE__
int _init_thread(pthread_internal_t* thread, pid_t kernel_id, bool add_to_thread_list) {
int error = 0;
thread->kernel_id = kernel_id;
// Set the scheduling policy/priority of the thread.
if (thread->attr.sched_policy != SCHED_NORMAL) {
struct sched_param param;
param.sched_priority = thread->attr.sched_priority;
if (sched_setscheduler(kernel_id, thread->attr.sched_policy, &param) == -1) {
// For backwards compatibility reasons, we just warn about failures here.
// error = errno;
const char* msg = "pthread_create sched_setscheduler call failed: %s\n";
__libc_format_log(ANDROID_LOG_WARN, "libc", msg, strerror(errno));
}
}
pthread_cond_init(&thread->join_cond, NULL);
thread->join_count = 0;
thread->cleanup_stack = NULL;
if (add_to_thread_list) {
_pthread_internal_add(thread);
}
return error;
}
static void *mkstack(size_t size, size_t guard_size)
{
pthread_mutex_lock(&mmap_lock);
int prot = PROT_READ | PROT_WRITE;
int flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE;
void* stack = mmap(NULL, size, prot, flags, -1, 0);
if (stack == MAP_FAILED) {
stack = NULL;
goto done;
}
if (mprotect(stack, guard_size, PROT_NONE) == -1) {
munmap(stack, size);
stack = NULL;
goto done;
}
done:
pthread_mutex_unlock(&mmap_lock);
return stack;
}
/*
* Create a new thread. The thread's stack is laid out like so:
*
* +---------------------------+
* | pthread_internal_t |
* +---------------------------+
* | |
* | TLS area |
* | |
* +---------------------------+
* | |
* . .
* . stack area .
* . .
* | |
* +---------------------------+
* | guard page |
* +---------------------------+
*
* note that TLS[0] must be a pointer to itself, this is required
* by the thread-local storage implementation of the x86 Linux
* kernel, where the TLS pointer is read by reading fs:[0]
*/
int pthread_create(pthread_t *thread_out, pthread_attr_t const * attr,
void *(*start_routine)(void *), void * arg)
{
int old_errno = errno;
/* this will inform the rest of the C library that at least one thread
* was created. this will enforce certain functions to acquire/release
* locks (e.g. atexit()) to protect shared global structures.
*
* this works because pthread_create() is not called by the C library
* initialization routine that sets up the main thread's data structures.
*/
__isthreaded = 1;
pthread_internal_t* thread = calloc(sizeof(*thread), 1);
if (thread == NULL) {
return EAGAIN;
}
thread->allocated_on_heap = true;
if (attr == NULL) {
pthread_attr_init(&thread->attr);
} else {
thread->attr = *attr;
attr = NULL; // Prevent misuse below.
}
// Make sure the stack size is PAGE_SIZE aligned.
size_t stack_size = (thread->attr.stack_size + (PAGE_SIZE-1)) & ~(PAGE_SIZE-1);
if (thread->attr.stack_base == NULL) {
// The caller didn't provide a stack, so allocate one.
thread->attr.stack_base = mkstack(stack_size, thread->attr.guard_size);
if (thread->attr.stack_base == NULL) {
free(thread);
return EAGAIN;
}
} else {
// The caller did provide a stack, so remember we're not supposed to free it.
thread->attr.flags |= PTHREAD_ATTR_FLAG_USER_STACK;
}
// Make room for TLS.
void** tls = (void**)((uint8_t*)(thread->attr.stack_base) + stack_size - BIONIC_TLS_SLOTS * sizeof(void*));
// Create a mutex for the thread in TLS_SLOT_SELF to wait on once it starts so we can keep
// it from doing anything until after we notify the debugger about it
//
// This also provides the memory barrier we need to ensure that all
// memory accesses previously performed by this thread are visible to
// the new thread.
pthread_mutex_t* start_mutex = (pthread_mutex_t*) &tls[TLS_SLOT_SELF];
pthread_mutex_init(start_mutex, NULL);
pthread_mutex_lock(start_mutex);
tls[TLS_SLOT_THREAD_ID] = thread;
int flags = CLONE_FILES | CLONE_FS | CLONE_VM | CLONE_SIGHAND |
CLONE_THREAD | CLONE_SYSVSEM | CLONE_DETACHED;
int tid = __pthread_clone((int(*)(void*))start_routine, tls, flags, arg);
if (tid < 0) {
int clone_errno = errno;
pthread_mutex_unlock(start_mutex);
if ((thread->attr.flags & PTHREAD_ATTR_FLAG_USER_STACK) == 0) {
munmap(thread->attr.stack_base, stack_size);
}
free(thread);
errno = old_errno;
return clone_errno;
}
int init_errno = _init_thread(thread, tid, true);
if (init_errno != 0) {
// Mark the thread detached and let its __thread_entry run to
// completion. (It'll just exit immediately, cleaning up its resources.)
thread->internal_flags |= kPthreadInitFailed;
thread->attr.flags |= PTHREAD_ATTR_FLAG_DETACHED;
pthread_mutex_unlock(start_mutex);
errno = old_errno;
return init_errno;
}
// Notify any debuggers about the new thread.
pthread_mutex_lock(&gDebuggerNotificationLock);
_thread_created_hook(tid);
pthread_mutex_unlock(&gDebuggerNotificationLock);
// Publish the pthread_t and let the thread run.
*thread_out = (pthread_t) thread;
pthread_mutex_unlock(start_mutex);
return 0;
}
/* CAVEAT: our implementation of pthread_cleanup_push/pop doesn't support C++ exceptions
* and thread cancelation
*/

232
libc/bionic/pthread_create.cpp Normal file
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@ -0,0 +1,232 @@
/*
* 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.h>
#include <errno.h>
#include <sys/mman.h>
#include "pthread_internal.h"
#include "private/bionic_ssp.h"
#include "private/bionic_tls.h"
#include "private/debug_format.h"
#include "private/logd.h"
#include "private/thread_private.h"
#include "private/ErrnoRestorer.h"
#include "private/ScopedPthreadMutexLocker.h"
extern "C" int __pthread_clone(int (*fn)(void*), void* child_stack, int flags, void* arg);
#ifdef __i386__
#define ATTRIBUTES __attribute__((noinline)) __attribute__((fastcall))
#else
#define ATTRIBUTES __attribute__((noinline))
#endif
extern "C" void ATTRIBUTES _thread_created_hook(pid_t thread_id);
static const int kPthreadInitFailed = 1;
static pthread_mutex_t gPthreadStackCreationLock = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t gDebuggerNotificationLock = PTHREAD_MUTEX_INITIALIZER;
void __init_tls(void** tls, void* thread) {
((pthread_internal_t*) thread)->tls = tls;
// Zero-initialize all the slots.
for (size_t i = 0; i < BIONIC_TLS_SLOTS; ++i) {
tls[i] = NULL;
}
// Slot 0 must point to itself. The x86 Linux kernel reads the TLS from %fs:0.
tls[TLS_SLOT_SELF] = tls;
tls[TLS_SLOT_THREAD_ID] = thread;
// GCC looks in the TLS for the stack guard on x86, so copy it there from our global.
tls[TLS_SLOT_STACK_GUARD] = (void*) __stack_chk_guard;
__set_tls((void*) tls);
}
// This trampoline is called from the assembly _pthread_clone() function.
extern "C" void __thread_entry(int (*func)(void*), void *arg, void **tls) {
// Wait for our creating thread to release us. This lets it have time to
// notify gdb about this thread before we start doing anything.
// This also provides the memory barrier needed to ensure that all memory
// accesses previously made by the creating thread are visible to us.
pthread_mutex_t* start_mutex = (pthread_mutex_t*) &tls[TLS_SLOT_SELF];
pthread_mutex_lock(start_mutex);
pthread_mutex_destroy(start_mutex);
pthread_internal_t* thread = (pthread_internal_t*) tls[TLS_SLOT_THREAD_ID];
__init_tls(tls, thread);
if ((thread->internal_flags & kPthreadInitFailed) != 0) {
pthread_exit(NULL);
}
int result = func(arg);
pthread_exit((void*) result);
}
__LIBC_ABI_PRIVATE__
int _init_thread(pthread_internal_t* thread, pid_t kernel_id, bool add_to_thread_list) {
int error = 0;
thread->kernel_id = kernel_id;
// Set the scheduling policy/priority of the thread.
if (thread->attr.sched_policy != SCHED_NORMAL) {
struct sched_param param;
param.sched_priority = thread->attr.sched_priority;
if (sched_setscheduler(kernel_id, thread->attr.sched_policy, &param) == -1) {
// For backwards compatibility reasons, we just warn about failures here.
// error = errno;
const char* msg = "pthread_create sched_setscheduler call failed: %s\n";
__libc_format_log(ANDROID_LOG_WARN, "libc", msg, strerror(errno));
}
}
pthread_cond_init(&thread->join_cond, NULL);
thread->join_count = 0;
thread->cleanup_stack = NULL;
if (add_to_thread_list) {
_pthread_internal_add(thread);
}
return error;
}
static void* __create_thread_stack(size_t stack_size, size_t guard_size) {
ScopedPthreadMutexLocker lock(&gPthreadStackCreationLock);
// Create a new private anonymous map.
int prot = PROT_READ | PROT_WRITE;
int flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE;
void* stack = mmap(NULL, stack_size, prot, flags, -1, 0);
if (stack == MAP_FAILED) {
return NULL;
}
// Set the guard region at the end of the stack to PROT_NONE.
if (mprotect(stack, guard_size, PROT_NONE) == -1) {
munmap(stack, stack_size);
return NULL;
}
return stack;
}
int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr,
void* (*start_routine)(void*), void* arg) {
ErrnoRestorer errno_restorer;
// Inform the rest of the C library that at least one thread
// was created. This will enforce certain functions to acquire/release
// locks (e.g. atexit()) to protect shared global structures.
// This works because pthread_create() is not called by the C library
// initialization routine that sets up the main thread's data structures.
__isthreaded = 1;
pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(calloc(sizeof(*thread), 1));
if (thread == NULL) {
return EAGAIN;
}
thread->allocated_on_heap = true;
if (attr == NULL) {
pthread_attr_init(&thread->attr);
} else {
thread->attr = *attr;
attr = NULL; // Prevent misuse below.
}
// Make sure the stack size is PAGE_SIZE aligned.
size_t stack_size = (thread->attr.stack_size + (PAGE_SIZE-1)) & ~(PAGE_SIZE-1);
if (thread->attr.stack_base == NULL) {
// The caller didn't provide a stack, so allocate one.
thread->attr.stack_base = __create_thread_stack(stack_size, thread->attr.guard_size);
if (thread->attr.stack_base == NULL) {
free(thread);
return EAGAIN;
}
} else {
// The caller did provide a stack, so remember we're not supposed to free it.
thread->attr.flags |= PTHREAD_ATTR_FLAG_USER_STACK;
}
// Make room for TLS.
void** tls = (void**)((uint8_t*)(thread->attr.stack_base) + stack_size - BIONIC_TLS_SLOTS * sizeof(void*));
// Create a mutex for the thread in TLS_SLOT_SELF to wait on once it starts so we can keep
// it from doing anything until after we notify the debugger about it
//
// This also provides the memory barrier we need to ensure that all
// memory accesses previously performed by this thread are visible to
// the new thread.
pthread_mutex_t* start_mutex = (pthread_mutex_t*) &tls[TLS_SLOT_SELF];
pthread_mutex_init(start_mutex, NULL);
ScopedPthreadMutexLocker start_locker(start_mutex);
tls[TLS_SLOT_THREAD_ID] = thread;
int flags = CLONE_FILES | CLONE_FS | CLONE_VM | CLONE_SIGHAND | CLONE_THREAD | CLONE_SYSVSEM | CLONE_DETACHED;
int tid = __pthread_clone((int(*)(void*))start_routine, tls, flags, arg);
if (tid < 0) {
int clone_errno = errno;
if ((thread->attr.flags & PTHREAD_ATTR_FLAG_USER_STACK) == 0) {
munmap(thread->attr.stack_base, stack_size);
}
free(thread);
return clone_errno;
}
int init_errno = _init_thread(thread, tid, true);
if (init_errno != 0) {
// Mark the thread detached and let its __thread_entry run to
// completion. (It'll just exit immediately, cleaning up its resources.)
thread->internal_flags |= kPthreadInitFailed;
thread->attr.flags |= PTHREAD_ATTR_FLAG_DETACHED;
return init_errno;
}
// Notify any debuggers about the new thread.
{
ScopedPthreadMutexLocker debugger_locker(&gDebuggerNotificationLock);
_thread_created_hook(tid);
}
// Publish the pthread_t and let the thread run.
*thread_out = (pthread_t) thread;
return 0;
}