pthread_create.cpp revision 03eebcb6e8762e668a0d3af6bb303cccb88c5b81
14b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes/* 24b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * Copyright (C) 2008 The Android Open Source Project 34b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * All rights reserved. 44b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * 54b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * Redistribution and use in source and binary forms, with or without 64b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * modification, are permitted provided that the following conditions 74b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * are met: 84b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * * Redistributions of source code must retain the above copyright 94b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * notice, this list of conditions and the following disclaimer. 104b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * * Redistributions in binary form must reproduce the above copyright 114b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * notice, this list of conditions and the following disclaimer in 124b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * the documentation and/or other materials provided with the 134b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * distribution. 144b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * 154b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 164b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 174b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 184b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 194b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 204b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 214b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 224b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 234b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 244b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 254b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 264b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes * SUCH DAMAGE. 274b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes */ 284b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 294b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes#include <pthread.h> 304b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 314b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes#include <errno.h> 324b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes#include <sys/mman.h> 334b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 344b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes#include "pthread_internal.h" 354b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 3603eebcb6e8762e668a0d3af6bb303cccb88c5b81Christopher Ferris#include "private/bionic_macros.h" 374b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes#include "private/bionic_ssp.h" 384b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes#include "private/bionic_tls.h" 398f2a5a0b40fc82126c691d5c30131d908772aab7Elliott Hughes#include "private/libc_logging.h" 404b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes#include "private/ErrnoRestorer.h" 414b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes#include "private/ScopedPthreadMutexLocker.h" 424b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 43af8aebebb52d73ea38c604525a6a5857618861cfElliott Hughes// Used by gdb to track thread creation. See libthread_db. 444b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes#ifdef __i386__ 45af8aebebb52d73ea38c604525a6a5857618861cfElliott Hughesextern "C" __attribute__((noinline)) __attribute__((fastcall)) void _thread_created_hook(pid_t) {} 464b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes#else 47af8aebebb52d73ea38c604525a6a5857618861cfElliott Hughesextern "C" __attribute__((noinline)) void _thread_created_hook(pid_t) {} 484b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes#endif 494b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 500d236aa3f1e6d31b0c729448ae9d3ed1cad23fb4Elliott Hughes// x86 uses segment descriptors rather than a direct pointer to TLS. 510d236aa3f1e6d31b0c729448ae9d3ed1cad23fb4Elliott Hughes#if __i386__ 520d236aa3f1e6d31b0c729448ae9d3ed1cad23fb4Elliott Hughes#include <asm/ldt.h> 530d236aa3f1e6d31b0c729448ae9d3ed1cad23fb4Elliott Hughesextern "C" __LIBC_HIDDEN__ void __init_user_desc(struct user_desc*, int, void*); 540d236aa3f1e6d31b0c729448ae9d3ed1cad23fb4Elliott Hughes#endif 550d236aa3f1e6d31b0c729448ae9d3ed1cad23fb4Elliott Hughes 56cd46104cf81aef14f9554bb4d9bced534a121471Elliott Hughesstatic pthread_mutex_t g_pthread_stack_creation_lock = PTHREAD_MUTEX_INITIALIZER; 574b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 581728b2396591853345507a063ed6075dfd251706Elliott Hughesstatic pthread_mutex_t g_debugger_notification_lock = PTHREAD_MUTEX_INITIALIZER; 594b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 60f2cea021ab2c6d7d7feeb40cca098aa132605876Elliott Hughesextern "C" int __isthreaded; 61f2cea021ab2c6d7d7feeb40cca098aa132605876Elliott Hughes 6270b24b1cc2a1a4436b1fea3f8b76616fdcb27224Elliott Hughes// This code is used both by each new pthread and the code that initializes the main thread. 63af8aebebb52d73ea38c604525a6a5857618861cfElliott Hughesvoid __init_tls(pthread_internal_t* thread) { 6470b24b1cc2a1a4436b1fea3f8b76616fdcb27224Elliott Hughes // Zero-initialize all the slots after TLS_SLOT_SELF and TLS_SLOT_THREAD_ID. 6570b24b1cc2a1a4436b1fea3f8b76616fdcb27224Elliott Hughes for (size_t i = TLS_SLOT_ERRNO; i < BIONIC_TLS_SLOTS; ++i) { 6640eabe24e4e3ae8ebe437f1f4e43cf39cbba2e9eElliott Hughes thread->tls[i] = NULL; 674b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } 684b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 694b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes // Slot 0 must point to itself. The x86 Linux kernel reads the TLS from %fs:0. 7040eabe24e4e3ae8ebe437f1f4e43cf39cbba2e9eElliott Hughes thread->tls[TLS_SLOT_SELF] = thread->tls; 7140eabe24e4e3ae8ebe437f1f4e43cf39cbba2e9eElliott Hughes thread->tls[TLS_SLOT_THREAD_ID] = thread; 724b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes // GCC looks in the TLS for the stack guard on x86, so copy it there from our global. 7340eabe24e4e3ae8ebe437f1f4e43cf39cbba2e9eElliott Hughes thread->tls[TLS_SLOT_STACK_GUARD] = (void*) __stack_chk_guard; 7470b24b1cc2a1a4436b1fea3f8b76616fdcb27224Elliott Hughes} 754b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 7670b24b1cc2a1a4436b1fea3f8b76616fdcb27224Elliott Hughesvoid __init_alternate_signal_stack(pthread_internal_t* thread) { 7784114c8dd5b17efecf7988f263ce431208d7be5aElliott Hughes // Create and set an alternate signal stack. 7884114c8dd5b17efecf7988f263ce431208d7be5aElliott Hughes stack_t ss; 7984114c8dd5b17efecf7988f263ce431208d7be5aElliott Hughes ss.ss_sp = mmap(NULL, SIGSTKSZ, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0); 8084114c8dd5b17efecf7988f263ce431208d7be5aElliott Hughes if (ss.ss_sp != MAP_FAILED) { 8184114c8dd5b17efecf7988f263ce431208d7be5aElliott Hughes ss.ss_size = SIGSTKSZ; 8284114c8dd5b17efecf7988f263ce431208d7be5aElliott Hughes ss.ss_flags = 0; 8384114c8dd5b17efecf7988f263ce431208d7be5aElliott Hughes sigaltstack(&ss, NULL); 8484114c8dd5b17efecf7988f263ce431208d7be5aElliott Hughes thread->alternate_signal_stack = ss.ss_sp; 8584114c8dd5b17efecf7988f263ce431208d7be5aElliott Hughes } 864b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes} 874b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 88cef3faec0ea40fdfe58e425fd0be64f00de6a26dElliott Hughesint __init_thread(pthread_internal_t* thread, bool add_to_thread_list) { 894b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes int error = 0; 904b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 914b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes // Set the scheduling policy/priority of the thread. 924b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes if (thread->attr.sched_policy != SCHED_NORMAL) { 93c3f114037dbf028896310609fd28cf2b3da99c4dElliott Hughes sched_param param; 944b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes param.sched_priority = thread->attr.sched_priority; 9540eabe24e4e3ae8ebe437f1f4e43cf39cbba2e9eElliott Hughes if (sched_setscheduler(thread->tid, thread->attr.sched_policy, ¶m) == -1) { 9698624c374646a050556bdc402b55b792fefa7e55Elliott Hughes#if __LP64__ 9798624c374646a050556bdc402b55b792fefa7e55Elliott Hughes // For backwards compatibility reasons, we only report failures on 64-bit devices. 9898624c374646a050556bdc402b55b792fefa7e55Elliott Hughes error = errno; 9998624c374646a050556bdc402b55b792fefa7e55Elliott Hughes#endif 100b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughes __libc_format_log(ANDROID_LOG_WARN, "libc", 101b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughes "pthread_create sched_setscheduler call failed: %s", strerror(errno)); 1024b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } 1034b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } 1044b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 1054b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes thread->cleanup_stack = NULL; 1064b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 1074b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes if (add_to_thread_list) { 1084b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes _pthread_internal_add(thread); 1094b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } 1104b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 1114b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes return error; 1124b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes} 1134b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 114b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughesstatic void* __create_thread_stack(pthread_internal_t* thread) { 115cd46104cf81aef14f9554bb4d9bced534a121471Elliott Hughes ScopedPthreadMutexLocker lock(&g_pthread_stack_creation_lock); 1164b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 1174b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes // Create a new private anonymous map. 1184b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes int prot = PROT_READ | PROT_WRITE; 1194b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes int flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE; 120b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughes void* stack = mmap(NULL, thread->attr.stack_size, prot, flags, -1, 0); 1214b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes if (stack == MAP_FAILED) { 122b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughes __libc_format_log(ANDROID_LOG_WARN, 123b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughes "libc", 124b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughes "pthread_create failed: couldn't allocate %zd-byte stack: %s", 125b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughes thread->attr.stack_size, strerror(errno)); 1264b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes return NULL; 1274b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } 1284b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 1294b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes // Set the guard region at the end of the stack to PROT_NONE. 130b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughes if (mprotect(stack, thread->attr.guard_size, PROT_NONE) == -1) { 131b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughes __libc_format_log(ANDROID_LOG_WARN, "libc", 132b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughes "pthread_create failed: couldn't mprotect PROT_NONE %zd-byte stack guard region: %s", 133b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughes thread->attr.guard_size, strerror(errno)); 134b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughes munmap(stack, thread->attr.stack_size); 1354b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes return NULL; 1364b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } 1374b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 1384b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes return stack; 1394b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes} 1404b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 141e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughesstatic int __pthread_start(void* arg) { 142e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughes pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(arg); 143e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughes 144e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughes // Wait for our creating thread to release us. This lets it have time to 145e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughes // notify gdb about this thread before we start doing anything. 146e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughes // This also provides the memory barrier needed to ensure that all memory 147e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughes // accesses previously made by the creating thread are visible to us. 148b30aff405a220495941f1673b0a5e66c4fa8b84cElliott Hughes pthread_mutex_lock(&thread->startup_handshake_mutex); 149b30aff405a220495941f1673b0a5e66c4fa8b84cElliott Hughes pthread_mutex_destroy(&thread->startup_handshake_mutex); 150e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughes 151e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughes __init_alternate_signal_stack(thread); 152e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughes 153e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughes void* result = thread->start_routine(thread->start_routine_arg); 154e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughes pthread_exit(result); 155e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughes 156e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughes return 0; 157e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughes} 158e48b68570d872ef7ece1d873c0ea298ea76393f3Elliott Hughes 159cef3faec0ea40fdfe58e425fd0be64f00de6a26dElliott Hughes// A dummy start routine for pthread_create failures where we've created a thread but aren't 160cef3faec0ea40fdfe58e425fd0be64f00de6a26dElliott Hughes// going to run user code on it. We swap out the user's start routine for this and take advantage 161cef3faec0ea40fdfe58e425fd0be64f00de6a26dElliott Hughes// of the regular thread teardown to free up resources. 162cef3faec0ea40fdfe58e425fd0be64f00de6a26dElliott Hughesstatic void* __do_nothing(void*) { 163cef3faec0ea40fdfe58e425fd0be64f00de6a26dElliott Hughes return NULL; 164cef3faec0ea40fdfe58e425fd0be64f00de6a26dElliott Hughes} 165cef3faec0ea40fdfe58e425fd0be64f00de6a26dElliott Hughes 1664b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughesint pthread_create(pthread_t* thread_out, pthread_attr_t const* attr, 1674b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes void* (*start_routine)(void*), void* arg) { 1684b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes ErrnoRestorer errno_restorer; 1694b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 170f2cea021ab2c6d7d7feeb40cca098aa132605876Elliott Hughes // Inform the rest of the C library that at least one thread was created. 1714b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes __isthreaded = 1; 1724b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 1734b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(calloc(sizeof(*thread), 1)); 1744b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes if (thread == NULL) { 175cfa089df23ff50fcd5ed3854c54991d30be5fc7eElliott Hughes __libc_format_log(ANDROID_LOG_WARN, "libc", "pthread_create failed: couldn't allocate thread"); 1764b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes return EAGAIN; 1774b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } 1784b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 1794b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes if (attr == NULL) { 1804b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes pthread_attr_init(&thread->attr); 1814b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } else { 1824b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes thread->attr = *attr; 1834b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes attr = NULL; // Prevent misuse below. 1844b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } 1854b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 186b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughes // Make sure the stack size and guard size are multiples of PAGE_SIZE. 18703eebcb6e8762e668a0d3af6bb303cccb88c5b81Christopher Ferris thread->attr.stack_size = BIONIC_ALIGN(thread->attr.stack_size, PAGE_SIZE); 18803eebcb6e8762e668a0d3af6bb303cccb88c5b81Christopher Ferris thread->attr.guard_size = BIONIC_ALIGN(thread->attr.guard_size, PAGE_SIZE); 1894b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 1904b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes if (thread->attr.stack_base == NULL) { 1914b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes // The caller didn't provide a stack, so allocate one. 192b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughes thread->attr.stack_base = __create_thread_stack(thread); 1934b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes if (thread->attr.stack_base == NULL) { 1944b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes free(thread); 1954b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes return EAGAIN; 1964b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } 1974b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } else { 1984b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes // The caller did provide a stack, so remember we're not supposed to free it. 1992b6e43e00ece68b3aba26d8f95f07cd9d9294ab4Elliott Hughes thread->attr.flags |= PTHREAD_ATTR_FLAG_USER_ALLOCATED_STACK; 2004b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } 2014b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 20284114c8dd5b17efecf7988f263ce431208d7be5aElliott Hughes // Make room for the TLS area. 20384114c8dd5b17efecf7988f263ce431208d7be5aElliott Hughes // The child stack is the same address, just growing in the opposite direction. 20484114c8dd5b17efecf7988f263ce431208d7be5aElliott Hughes // At offsets >= 0, we have the TLS slots. 20584114c8dd5b17efecf7988f263ce431208d7be5aElliott Hughes // At offsets < 0, we have the child stack. 206b30aff405a220495941f1673b0a5e66c4fa8b84cElliott Hughes thread->tls = reinterpret_cast<void**>(reinterpret_cast<uint8_t*>(thread->attr.stack_base) + 207b30aff405a220495941f1673b0a5e66c4fa8b84cElliott Hughes thread->attr.stack_size - BIONIC_TLS_SLOTS * sizeof(void*)); 20870b24b1cc2a1a4436b1fea3f8b76616fdcb27224Elliott Hughes void* child_stack = thread->tls; 2090d236aa3f1e6d31b0c729448ae9d3ed1cad23fb4Elliott Hughes __init_tls(thread); 2104b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 21170b24b1cc2a1a4436b1fea3f8b76616fdcb27224Elliott Hughes // Create a mutex for the thread in TLS to wait on once it starts so we can keep 2124b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes // it from doing anything until after we notify the debugger about it 2134b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes // 2144b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes // This also provides the memory barrier we need to ensure that all 2154b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes // memory accesses previously performed by this thread are visible to 2164b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes // the new thread. 217b30aff405a220495941f1673b0a5e66c4fa8b84cElliott Hughes pthread_mutex_init(&thread->startup_handshake_mutex, NULL); 218b30aff405a220495941f1673b0a5e66c4fa8b84cElliott Hughes pthread_mutex_lock(&thread->startup_handshake_mutex); 2194b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 22070b24b1cc2a1a4436b1fea3f8b76616fdcb27224Elliott Hughes thread->start_routine = start_routine; 22170b24b1cc2a1a4436b1fea3f8b76616fdcb27224Elliott Hughes thread->start_routine_arg = arg; 2224b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 223877ec6d90418ff1d6597147d355a2229fdffae7eElliott Hughes int flags = CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD | CLONE_SYSVSEM | 224877ec6d90418ff1d6597147d355a2229fdffae7eElliott Hughes CLONE_SETTLS | CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID; 2250d236aa3f1e6d31b0c729448ae9d3ed1cad23fb4Elliott Hughes void* tls = thread->tls; 22680906141f79be8be63fc915bfab467029b442ca1Elliott Hughes#if defined(__i386__) 22780906141f79be8be63fc915bfab467029b442ca1Elliott Hughes // On x86 (but not x86-64), CLONE_SETTLS takes a pointer to a struct user_desc rather than 2280d236aa3f1e6d31b0c729448ae9d3ed1cad23fb4Elliott Hughes // a pointer to the TLS itself. 2290d236aa3f1e6d31b0c729448ae9d3ed1cad23fb4Elliott Hughes user_desc tls_descriptor; 2300d236aa3f1e6d31b0c729448ae9d3ed1cad23fb4Elliott Hughes __init_user_desc(&tls_descriptor, false, tls); 2310d236aa3f1e6d31b0c729448ae9d3ed1cad23fb4Elliott Hughes tls = &tls_descriptor; 23280906141f79be8be63fc915bfab467029b442ca1Elliott Hughes#endif 2330d236aa3f1e6d31b0c729448ae9d3ed1cad23fb4Elliott Hughes int rc = clone(__pthread_start, child_stack, flags, thread, &(thread->tid), tls, &(thread->tid)); 234877ec6d90418ff1d6597147d355a2229fdffae7eElliott Hughes if (rc == -1) { 2354b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes int clone_errno = errno; 236877ec6d90418ff1d6597147d355a2229fdffae7eElliott Hughes // We don't have to unlock the mutex at all because clone(2) failed so there's no child waiting to 237877ec6d90418ff1d6597147d355a2229fdffae7eElliott Hughes // be unblocked, but we're about to unmap the memory the mutex is stored in, so this serves as a 238877ec6d90418ff1d6597147d355a2229fdffae7eElliott Hughes // reminder that you can't rewrite this function to use a ScopedPthreadMutexLocker. 239b30aff405a220495941f1673b0a5e66c4fa8b84cElliott Hughes pthread_mutex_unlock(&thread->startup_handshake_mutex); 2402b6e43e00ece68b3aba26d8f95f07cd9d9294ab4Elliott Hughes if ((thread->attr.flags & PTHREAD_ATTR_FLAG_USER_ALLOCATED_STACK) == 0) { 241b95cf0d23a1db3b7c37bd98b0c86196796c9b029Elliott Hughes munmap(thread->attr.stack_base, thread->attr.stack_size); 2424b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } 2434b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes free(thread); 244cfa089df23ff50fcd5ed3854c54991d30be5fc7eElliott Hughes __libc_format_log(ANDROID_LOG_WARN, "libc", "pthread_create failed: clone failed: %s", strerror(errno)); 2454b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes return clone_errno; 2464b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } 2474b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 248cef3faec0ea40fdfe58e425fd0be64f00de6a26dElliott Hughes int init_errno = __init_thread(thread, true); 2494b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes if (init_errno != 0) { 250cef3faec0ea40fdfe58e425fd0be64f00de6a26dElliott Hughes // Mark the thread detached and replace its start_routine with a no-op. 251cef3faec0ea40fdfe58e425fd0be64f00de6a26dElliott Hughes // Letting the thread run is the easiest way to clean up its resources. 2524b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes thread->attr.flags |= PTHREAD_ATTR_FLAG_DETACHED; 253cef3faec0ea40fdfe58e425fd0be64f00de6a26dElliott Hughes thread->start_routine = __do_nothing; 254b30aff405a220495941f1673b0a5e66c4fa8b84cElliott Hughes pthread_mutex_unlock(&thread->startup_handshake_mutex); 2554b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes return init_errno; 2564b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } 2574b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 2584b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes // Notify any debuggers about the new thread. 2594b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes { 2601728b2396591853345507a063ed6075dfd251706Elliott Hughes ScopedPthreadMutexLocker debugger_locker(&g_debugger_notification_lock); 26140eabe24e4e3ae8ebe437f1f4e43cf39cbba2e9eElliott Hughes _thread_created_hook(thread->tid); 2624b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes } 2634b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 264877ec6d90418ff1d6597147d355a2229fdffae7eElliott Hughes // Publish the pthread_t and unlock the mutex to let the new thread start running. 265877ec6d90418ff1d6597147d355a2229fdffae7eElliott Hughes *thread_out = reinterpret_cast<pthread_t>(thread); 266b30aff405a220495941f1673b0a5e66c4fa8b84cElliott Hughes pthread_mutex_unlock(&thread->startup_handshake_mutex); 2674b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes 2684b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes return 0; 2694b4a8824289c48c823cd38bc63289d121aae3d67Elliott Hughes} 270