platform_bionic/libc/bionic/pthread_internal.h
Elliott Hughes 877ec6d904 Fix pthread_join.
Let the kernel keep pthread_internal_t::tid updated, including
across forks and for the main thread. This then lets us fix
pthread_join to only return after the thread has really exited.

Also fix the thread attributes of the main thread so we don't
unmap the main thread's stack (which is really owned by the
dynamic linker and contains things like environment variables),
which fixes crashes when joining with an exited main thread
and also fixes problems reported publicly with accessing environment
variables after the main thread exits (for which I've added a new
unit test).

In passing I also fixed a bug where if the clone(2) inside
pthread_create(3) fails, we'd unmap the child's stack and TLS (which
contains the mutex) and then try to unlock the mutex. Boom! It wasn't
until after I'd uploaded the fix for this that I came across a new
public bug reporting this exact failure.

Bug: 8206355
Bug: 11693195
Bug: https://code.google.com/p/android/issues/detail?id=57421
Bug: https://code.google.com/p/android/issues/detail?id=62392
Change-Id: I2af9cf6e8ae510a67256ad93cad891794ed0580b
2013-11-18 19:48:11 -08:00

102 lines
3.9 KiB
C

/*
* 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.
*/
#ifndef _PTHREAD_INTERNAL_H_
#define _PTHREAD_INTERNAL_H_
#include <pthread.h>
struct pthread_internal_t {
struct pthread_internal_t* next;
struct pthread_internal_t* prev;
pid_t tid;
void** tls;
pthread_attr_t attr;
bool allocated_on_heap; /* TODO: move this into attr.flags? */
int internal_flags; /* TODO: move this into attr.flags? */
__pthread_cleanup_t* cleanup_stack;
void* (*start_routine)(void*);
void* start_routine_arg;
void* return_value;
void* alternate_signal_stack;
/*
* The dynamic linker implements dlerror(3), which makes it hard for us to implement this
* per-thread buffer by simply using malloc(3) and free(3).
*/
#define __BIONIC_DLERROR_BUFFER_SIZE 512
char dlerror_buffer[__BIONIC_DLERROR_BUFFER_SIZE];
};
__LIBC_HIDDEN__ int _init_thread(pthread_internal_t* thread, bool add_to_thread_list);
__LIBC_HIDDEN__ void __init_tls(pthread_internal_t* thread);
__LIBC_HIDDEN__ void __init_alternate_signal_stack(pthread_internal_t*);
__LIBC_HIDDEN__ void _pthread_internal_add(pthread_internal_t* thread);
__LIBC_HIDDEN__ pthread_internal_t* __get_thread(void);
__LIBC_HIDDEN__ void pthread_key_clean_all(void);
__LIBC_HIDDEN__ void _pthread_internal_remove_locked(pthread_internal_t* thread);
/* Has the thread been detached by a pthread_join or pthread_detach call? */
#define PTHREAD_ATTR_FLAG_DETACHED 0x00000001
/* Was the thread's stack allocated by the user rather than by us? */
#define PTHREAD_ATTR_FLAG_USER_ALLOCATED_STACK 0x00000002
/* Has the thread been joined by another thread? */
#define PTHREAD_ATTR_FLAG_JOINED 0x00000004
#define PTHREAD_INTERNAL_FLAG_THREAD_INIT_FAILED 1
/*
* Traditionally we give threads a 1MiB stack. When we started
* allocating per-thread alternate signal stacks to ease debugging of
* stack overflows, we subtracted the same amount we were using there
* from the default thread stack size. This should keep memory usage
* roughly constant.
*/
#define PTHREAD_STACK_SIZE_DEFAULT ((1 * 1024 * 1024) - SIGSTKSZ)
__LIBC_HIDDEN__ extern pthread_internal_t* gThreadList;
__LIBC_HIDDEN__ extern pthread_mutex_t gThreadListLock;
__LIBC_HIDDEN__ int __timespec_to_absolute(timespec*, const timespec*, clockid_t);
/* needed by fork.c */
__LIBC_HIDDEN__ extern void __timer_table_start_stop(int);
__LIBC_HIDDEN__ extern void __bionic_atfork_run_prepare();
__LIBC_HIDDEN__ extern void __bionic_atfork_run_child();
__LIBC_HIDDEN__ extern void __bionic_atfork_run_parent();
__LIBC_HIDDEN__ extern int __pthread_settid(pthread_t, pid_t);
#endif /* _PTHREAD_INTERNAL_H_ */