int gtthread_create(gtthread_t *thread, gtthread_attr_t const * attr,
void *(*start_routine)(void *), void * arg)
{
//allocate memory for the thread and initialize to 0
gtthread_t* gt_thread = calloc(sizeof(*gt_thread),1);
if(gt_thread==NULL){
return -1;
}
//check the thread attribute object
if(attr==NULL){
*attr = default_gtthread_attr;
}
//create or retrieve a new stack for the thread if NULL
size_t stack_size = attr->stack_size;
uint8_t stack_base = attr->stack_base;
if(stack_base==NULL){
stack_base = malloc(stack_size);
if(stack_base==NULL){ //check for unsuccessful malloc
return -1;
}
}
stack_base = stack_base + stack_size;
int flags = CLONE_FILES | CLONE_FS | CLONE_VM | CLONE_SIGHAND |
CLONE_THREAD | CLONE_SYSVSEM | CLONE_DETACHED;
int tid = __pthread_clone((int(*)(void*))start_routine, stack_base, flags, arg);
if(tid<0){ //check for unsuccessful clone
return -1;
}
int init_errno = _init_thread(thread, tid, (pthread_attr_t*) attr, stack_base, 1);
return 0;
}
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) {
__libc_format_log(ANDROID_LOG_WARN, "libc", "pthread_create failed: couldn't allocate thread");
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);
__libc_format_log(ANDROID_LOG_WARN, "libc", "pthread_create failed: couldn't allocate %zd-byte stack", stack_size);
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;
int tid = __pthread_clone(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);
__libc_format_log(ANDROID_LOG_WARN, "libc", "pthread_create failed: clone failed: %s", strerror(errno));
return clone_errno;
}
thread->tid = tid;
int init_errno = _init_thread(thread, 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(thread->tid);
}
// Publish the pthread_t and let the thread run.
*thread_out = (pthread_t) thread;
return 0;
}
TEST(pthread, __pthread_clone) {
uintptr_t fake_child_stack[16];
errno = 0;
ASSERT_EQ(-1, __pthread_clone(NULL, &fake_child_stack[0], CLONE_THREAD, NULL));
ASSERT_EQ(EINVAL, errno);
}
