platform_bionic/libc/bionic/pthread_internal.h
msg555 0f020d18b1 Handles spurious wake-ups in pthread_join()
Removed 'join_count' from pthread_internal_t and switched to using the flag
PTHREAD_ATTR_FLAG_JOINED to indicate if a thread is being joined. Combined with
a switch to a while loop in pthread_join, this fixes spurious wake-ups but
prevents a thread from being joined multiple times. This is fine for
two reasons:

1) The pthread_join specification allows for undefined behavior when multiple
   threads try to join a single thread.

2) There is no thread safe way to allow multiple threads to join a single
   thread with the pthread interface.  The second thread calling pthread_join
   could be pre-empted until the thread is destroyed and its handle reused for
   a different thread.  Therefore multi-join is always an error.

Bug: https://code.google.com/p/android/issues/detail?id=52255
Change-Id: I8b6784d47620ffdcdbfb14524e7402e21d46c5f7
2013-06-12 17:30:58 -07:00

148 lines
5.1 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>
#include <stdbool.h>
#include <sys/cdefs.h>
__BEGIN_DECLS
typedef struct pthread_internal_t
{
struct pthread_internal_t* next;
struct pthread_internal_t* prev;
pthread_attr_t attr;
pid_t tid;
bool allocated_on_heap;
pthread_cond_t join_cond;
void* return_value;
int internal_flags;
__pthread_cleanup_t* cleanup_stack;
void** tls; /* thread-local storage area */
/*
* 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];
} pthread_internal_t;
int _init_thread(pthread_internal_t* thread, bool add_to_thread_list);
void __init_tls(pthread_internal_t* thread);
void _pthread_internal_add(pthread_internal_t* thread);
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_STACK 0x00000002
/* Has the thread been joined by another thread? */
#define PTHREAD_ATTR_FLAG_JOINED 0x00000004
/* Has the thread already exited but not been joined? */
#define PTHREAD_ATTR_FLAG_ZOMBIE 0x00000008
__LIBC_HIDDEN__ extern pthread_internal_t* gThreadList;
__LIBC_HIDDEN__ extern pthread_mutex_t gThreadListLock;
/* needed by posix-timers.c */
static __inline__ void timespec_add( struct timespec* a, const struct timespec* b )
{
a->tv_sec += b->tv_sec;
a->tv_nsec += b->tv_nsec;
if (a->tv_nsec >= 1000000000) {
a->tv_nsec -= 1000000000;
a->tv_sec += 1;
}
}
static __inline__ void timespec_sub( struct timespec* a, const struct timespec* b )
{
a->tv_sec -= b->tv_sec;
a->tv_nsec -= b->tv_nsec;
if (a->tv_nsec < 0) {
a->tv_nsec += 1000000000;
a->tv_sec -= 1;
}
}
static __inline__ void timespec_zero( struct timespec* a )
{
a->tv_sec = a->tv_nsec = 0;
}
static __inline__ int timespec_is_zero( const struct timespec* a )
{
return (a->tv_sec == 0 && a->tv_nsec == 0);
}
static __inline__ int timespec_cmp( const struct timespec* a, const struct timespec* b )
{
if (a->tv_sec < b->tv_sec) return -1;
if (a->tv_sec > b->tv_sec) return +1;
if (a->tv_nsec < b->tv_nsec) return -1;
if (a->tv_nsec > b->tv_nsec) return +1;
return 0;
}
static __inline__ int timespec_cmp0( const struct timespec* a )
{
if (a->tv_sec < 0) return -1;
if (a->tv_sec > 0) return +1;
if (a->tv_nsec < 0) return -1;
if (a->tv_nsec > 0) return +1;
return 0;
}
extern int __pthread_cond_timedwait(pthread_cond_t*,
pthread_mutex_t*,
const struct timespec*,
clockid_t);
extern int __pthread_cond_timedwait_relative(pthread_cond_t*,
pthread_mutex_t*,
const struct timespec*);
/* needed by fork.c */
extern void __timer_table_start_stop(int stop);
extern void __bionic_atfork_run_prepare();
extern void __bionic_atfork_run_child();
extern void __bionic_atfork_run_parent();
__END_DECLS
#endif /* _PTHREAD_INTERNAL_H_ */