Clean up pthread_create.
Bug: 3461078
Change-Id: I082122a86d7692cd58f4145539241be026258ee0
diff --git a/libc/bionic/pthread_create.cpp b/libc/bionic/pthread_create.cpp
new file mode 100644
index 0000000..6e4fe45
--- /dev/null
+++ b/libc/bionic/pthread_create.cpp
@@ -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, ¶m) == -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;
+}