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/*
* debug_mutex.h: debugging wrappers for pthread_mutex_ functions
*
* See the main source file 'xineliboutput.c' for copyright information and
* how to reach the author.
*
* $Id: debug_mutex.h,v 1.3 2007/03/14 11:50:08 phintuka Exp $
*
*/
#ifndef DEBUG_MUTEX_H
#define DEBUG_MUTEX_H
#ifndef _PTHREAD_H
# error pthread.h must be included before debug_mutex.h
#endif
/*
* Override pthread_mutex_ calls:
*
* Change type of each mutex to PTHREAD_MUTEX_ERRORCHECK_NP
*
* Store line number of last succeed pthread_mutex_lock call
* for each initialized mutex
*
* Check every pthread_mutex_ call for errors and log all errors
*
* To help detecting deadlocks and minimize logging:
* - Try locking first in pthread_mutex_lock
* - If pthread_mutex_trylock fails, log a message and retry.
* - When trylock failed, log another message when lock is acquired.
*
*
* NOTE: debugging itself is not thread-safe and may indicate wrong line numbers !
*
*/
#define MAX_DBG_MUTEX 64
static struct {
pthread_mutex_t *lock;
int line;
int tid;
} dbgdata[MAX_DBG_MUTEX+1] = {{NULL,0}};
static void dbg_setdata(pthread_mutex_t *mutex, int line)
{
int i;
for(i=0; i<MAX_DBG_MUTEX; i++)
if(dbgdata[i].lock == mutex) {
dbgdata[i].line = line;
dbgdata[i].tid = syscall(__NR_gettid);
return;
}
LOGMSG("********** dbg_setdata: new entry (0x%lx at %d)", (unsigned long int)mutex, line);
for(i=0; i<MAX_DBG_MUTEX; i++)
if(!dbgdata[i].lock) {
dbgdata[i].lock = mutex;
dbgdata[i].line = line;
dbgdata[i].tid = syscall(__NR_gettid);
return;
}
LOGMSG("********** dbg_setdata: table full !");
}
static int dbg_getdata(pthread_mutex_t *mutex, int line)
{
int i;
for(i=0; i<MAX_DBG_MUTEX; i++)
if(dbgdata[i].lock == mutex)
return dbgdata[i].line;
LOGMSG("********** dbg_getdata: NO ENTRY ! (%d)", line);
return -1;
}
static void dbg_deldata(pthread_mutex_t *mutex, int line)
{
int i;
for(i=0; i<MAX_DBG_MUTEX; i++)
if(dbgdata[i].lock == mutex) {
dbgdata[i].lock = NULL;
return;
}
LOGMSG("********** dbg_deldata: NO ENTRY ! (%d)", line);
return;
}
static int dbg_init(pthread_mutex_t *mutex, pthread_mutexattr_t *pattr, int line)
{
int r;
errno = 0;
if(!pattr) {
pthread_mutexattr_t attr;
pthread_mutexattr_init(&attr);
pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK_NP);
r = pthread_mutex_init(mutex, &attr);
} else {
LOGMSG("********** dbg_init: mutex attribute already given !");
r = pthread_mutex_init(mutex, pattr);
}
if(r)
LOGERR("********** dbg_init: pthread_mutex_init FAILED at %d", line);
dbg_setdata(mutex, line);
return r;
}
static int dbg_free(pthread_mutex_t *mutex, int line)
{
int r;
errno = 0;
r = pthread_mutex_destroy(mutex);
if(r)
LOGERR("********** dbg_free: pthread_mutex_destroy FAILED at %d ; last lock at %d",
line, dbg_getdata(mutex, line));
dbg_deldata(mutex, line);
return r;
}
static int dbg_lock(pthread_mutex_t *mutex, int line)
{
int r;
/*struct timespec abs_timeout;*/
/* try lock first to reduce logging */
errno = 0;
r = pthread_mutex_trylock(mutex);
if(!r) {
dbg_setdata(mutex,line);
return r;
}
/* try failed - we're going to wait, so log at wait start and end to detect deadlocks */
LOGERR("********** dbg_lock: pthread_mutex_trylock failed at %d (locked at %d)",
line, dbg_getdata(mutex, line));
/* int pthread_mutex_timedlock(pthread_mutex_t *restrict mutex,
const struct timespec *restrict abs_timeout); */
errno = 0;
r = pthread_mutex_lock(mutex);
if(r)
LOGERR("********** dbg_lock: pthread_mutex_lock FAILED at %d", line);
dbg_setdata(mutex, line);
LOGMSG("********** dbg_lock: pthread_mutex_lock done at %d", line);
return r;
}
static int dbg_trylock(pthread_mutex_t *mutex, int line)
{
int r;
/*struct timespec abs_timeout;*/
/* try lock first to reduce logging */
errno = 0;
r = pthread_mutex_trylock(mutex);
if(!r) {
dbg_setdata(mutex,line);
return r;
}
LOGERR("********** dbg_trylock: pthread_mutex_trylock failed at %d (locked at %d)",
line, dbg_getdata(mutex, line));
return r;
}
static int dbg_unlock(pthread_mutex_t *mutex, int line)
{
int r;
errno = 0;
r = pthread_mutex_unlock(mutex);
if(r)
LOGERR("********** dbg_unlock: pthread_mutex_unlock FAILED at %d (last locket at %d)",
line, dbg_getdata(mutex, line));
//else
// dbg_setdata(mutex, 0);
return r;
}
/* override pthread_ functions with own ones */
#define pthread_mutex_init(l,a) dbg_init(l, a, __LINE__)
#define pthread_mutex_lock(l) dbg_lock(l, __LINE__)
#define pthread_mutex_trylock(l) dbg_trylock(l, __LINE__)
#define pthread_mutex_unlock(l) dbg_unlock(l, __LINE__)
#define pthread_mutex_destroy(l) dbg_free(l, __LINE__)
#else
# error debug_mutex.h included twice
#endif /* DEBUG_MUTEX_H */
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