/**
* Locking routine.
* @param type: as passed by user.
* @param lock: as passed by user.
* @param func: caller location.
* @param file: caller location.
* @param line: caller location.
* @param tryfunc: the pthread_mutex_trylock or similar function.
* @param timedfunc: the pthread_mutex_timedlock or similar function.
* Uses absolute timeout value.
* @param arg: what to pass to tryfunc and timedlock.
* @param exclusive: if lock must be exclusive (only one allowed).
* @param getwr: if attempts to get writelock (or readlock) for rwlocks.
*/
static void
checklock_lockit(enum check_lock_type type, struct checked_lock* lock,
const char* func, const char* file, int line,
int (*tryfunc)(void*), int (*timedfunc)(void*, struct timespec*),
void* arg, int exclusive, int getwr)
{
int err;
int contend = 0;
struct thr_check *thr = (struct thr_check*)pthread_getspecific(
thr_debug_key);
checktype(type, lock, func, file, line);
if(!thr) lock_error(lock, func, file, line, "no thread info");
acquire_locklock(lock, func, file, line);
lock->wait_count ++;
thr->waiting = lock;
if(exclusive && lock->hold_count > 0 && lock->holder == thr)
lock_error(lock, func, file, line, "thread already owns lock");
if(type==check_lock_rwlock && getwr && lock->writeholder == thr)
lock_error(lock, func, file, line, "thread already has wrlock");
LOCKRET(pthread_mutex_unlock(&lock->lock));
/* first try; if busy increase contention counter */
if((err=tryfunc(arg))) {
struct timespec to;
if(err != EBUSY) log_err("trylock: %s", strerror(err));
to.tv_sec = time(NULL) + CHECK_LOCK_TIMEOUT;
to.tv_nsec = 0;
if((err=timedfunc(arg, &to))) {
if(err == ETIMEDOUT)
lock_error(lock, func, file, line,
"timeout possible deadlock");
log_err("timedlock: %s", strerror(err));
}
contend ++;
}
/* got the lock */
acquire_locklock(lock, func, file, line);
lock->contention_count += contend;
lock->history_count++;
if(exclusive && lock->hold_count > 0)
lock_error(lock, func, file, line, "got nonexclusive lock");
if(type==check_lock_rwlock && getwr && lock->writeholder)
lock_error(lock, func, file, line, "got nonexclusive wrlock");
if(type==check_lock_rwlock && getwr)
lock->writeholder = thr;
/* check the memory areas for unauthorized changes,
* between last unlock time and current lock time.
* we check while holding the lock (threadsafe).
*/
if(getwr || exclusive)
prot_check(lock, func, file, line);
finish_acquire_lock(thr, lock, func, file, line);
LOCKRET(pthread_mutex_unlock(&lock->lock));
}
/** check if OK, free struct */
void
checklock_destroy(enum check_lock_type type, struct checked_lock** lock,
const char* func, const char* file, int line)
{
const size_t contention_interest = 1; /* promille contented locks */
struct checked_lock* e;
if(!lock)
return;
e = *lock;
if(!e)
return;
checktype(type, e, func, file, line);
/* check if delete is OK */
acquire_locklock(e, func, file, line);
if(e->hold_count != 0)
lock_error(e, func, file, line, "delete while locked.");
if(e->wait_count != 0)
lock_error(e, func, file, line, "delete while waited on.");
prot_check(e, func, file, line);
*lock = NULL; /* use after free will fail */
LOCKRET(pthread_mutex_unlock(&e->lock));
/* contention, look at fraction in trouble. */
if(e->history_count > 1 &&
1000*e->contention_count/e->history_count > contention_interest) {
log_info("lock created %s %s %d has contention %u of %u (%d%%)",
e->create_func, e->create_file, e->create_line,
(unsigned int)e->contention_count,
(unsigned int)e->history_count,
(int)(100*e->contention_count/e->history_count));
}
/* delete it */
LOCKRET(pthread_mutex_destroy(&e->lock));
prot_clear(e);
/* since nobody holds the lock - see check above, no need to unlink
* from the thread-held locks list. */
switch(e->type) {
case check_lock_mutex:
LOCKRET(pthread_mutex_destroy(&e->u.mutex));
break;
case check_lock_spinlock:
LOCKRET(pthread_spin_destroy(&e->u.spinlock));
break;
case check_lock_rwlock:
LOCKRET(pthread_rwlock_destroy(&e->u.rwlock));
break;
default:
log_assert(0);
}
memset(e, 0, sizeof(struct checked_lock));
free(e);
}
/** alloc struct, init lock empty */
void
checklock_init(enum check_lock_type type, struct checked_lock** lock,
const char* func, const char* file, int line)
{
struct checked_lock* e = (struct checked_lock*)calloc(1,
sizeof(struct checked_lock));
struct thr_check *thr = (struct thr_check*)pthread_getspecific(
thr_debug_key);
if(!e)
fatal_exit("%s %s %d: out of memory", func, file, line);
if(!thr) {
/* this is called when log_init() calls lock_init()
* functions, and the test check code has not yet
* been initialised. But luckily, the checklock_start()
* routine can be called multiple times without ill effect.
*/
checklock_start();
thr = (struct thr_check*)pthread_getspecific(thr_debug_key);
}
if(!thr)
fatal_exit("%s %s %d: lock_init no thread info", func, file,
line);
*lock = e;
e->type = type;
e->create_func = func;
e->create_file = file;
e->create_line = line;
e->create_thread = thr->num;
e->create_instance = thr->locks_created++;
ordercheck_lockcreate(thr, e);
LOCKRET(pthread_mutex_init(&e->lock, NULL));
switch(e->type) {
case check_lock_mutex:
LOCKRET(pthread_mutex_init(&e->u.mutex, NULL));
break;
case check_lock_spinlock:
LOCKRET(pthread_spin_init(&e->u.spinlock, PTHREAD_PROCESS_PRIVATE));
break;
case check_lock_rwlock:
LOCKRET(pthread_rwlock_init(&e->u.rwlock, NULL));
break;
default:
log_assert(0);
}
}
/** init the main thread */
void checklock_start(void)
{
if(key_deleted)
return;
if(!key_created) {
struct thr_check* thisthr = (struct thr_check*)calloc(1,
sizeof(struct thr_check));
if(!thisthr)
fatal_exit("thrcreate: out of memory");
key_created = 1;
check_lock_pid = getpid();
LOCKRET(pthread_key_create(&thr_debug_key, NULL));
LOCKRET(pthread_setspecific(thr_debug_key, thisthr));
thread_infos[0] = thisthr;
if(check_locking_order)
open_lockorder(thisthr);
}
}
/** wait for thread with a timeout */
void
checklock_thrjoin(pthread_t thread)
{
/* wait with a timeout */
if(signal(SIGALRM, joinalarm) == SIG_ERR)
fatal_exit("signal(): %s", strerror(errno));
(void)alarm(CHECK_JOIN_TIMEOUT);
LOCKRET(pthread_join(thread, NULL));
(void)alarm(0);
}
/** allocate debug info and create thread */
void
checklock_thrcreate(pthread_t* id, void* (*func)(void*), void* arg)
{
struct thr_check* thr = (struct thr_check*)calloc(1,
sizeof(struct thr_check));
if(!thr)
fatal_exit("thrcreate: out of memory");
if(!key_created) {
checklock_start();
}
thr->func = func;
thr->arg = arg;
LOCKRET(pthread_create(id, NULL, checklock_main, thr));
}
/** remove protected region */
void
lock_unprotect(void* mangled, void* area)
{
struct checked_lock* lock = *(struct checked_lock**)mangled;
struct protected_area* p, **prevp;
if(!lock)
return;
acquire_locklock(lock, __func__, __FILE__, __LINE__);
p = lock->prot;
prevp = &lock->prot;
while(p) {
if(p->region == area) {
*prevp = p->next;
free(p->hold);
free(p);
LOCKRET(pthread_mutex_unlock(&lock->lock));
return;
}
prevp = &p->next;
p = p->next;
}
LOCKRET(pthread_mutex_unlock(&lock->lock));
}
/** get memory held by lock */
size_t
lock_get_mem(void* pp)
{
size_t s;
struct checked_lock* lock = *(struct checked_lock**)pp;
struct protected_area* p;
s = sizeof(struct checked_lock);
acquire_locklock(lock, __func__, __FILE__, __LINE__);
for(p = lock->prot; p; p = p->next) {
s += sizeof(struct protected_area);
s += p->size;
}
LOCKRET(pthread_mutex_unlock(&lock->lock));
return s;
}
/** stop checklocks */
void checklock_stop(void)
{
if(key_created) {
int i;
key_deleted = 1;
if(check_locking_order)
fclose(thread_infos[0]->order_info);
free(thread_infos[0]);
thread_infos[0] = NULL;
for(i = 0; i < THRDEBUG_MAX_THREADS; i++)
log_assert(thread_infos[i] == NULL);
/* should have been cleaned up. */
LOCKRET(pthread_key_delete(thr_debug_key));
key_created = 0;
}
}
/** add protected region */
void
lock_protect(void *p, void* area, size_t size)
{
struct checked_lock* lock = *(struct checked_lock**)p;
struct protected_area* e = (struct protected_area*)malloc(
sizeof(struct protected_area));
if(!e)
fatal_exit("lock_protect: out of memory");
e->region = area;
e->size = size;
e->hold = malloc(size);
if(!e->hold)
fatal_exit("lock_protect: out of memory");
memcpy(e->hold, e->region, e->size);
acquire_locklock(lock, __func__, __FILE__, __LINE__);
e->next = lock->prot;
lock->prot = e;
LOCKRET(pthread_mutex_unlock(&lock->lock));
}
/** checklock thread main, Inits thread structure */
static void* checklock_main(void* arg)
{
struct thr_check* thr = (struct thr_check*)arg;
void* ret;
thr->id = pthread_self();
/* Hack to get same numbers as in log file */
thr->num = *(int*)(thr->arg);
log_assert(thr->num < THRDEBUG_MAX_THREADS);
/* as an aside, due to this, won't work for libunbound bg thread */
if(thread_infos[thr->num] != NULL)
log_warn("thread warning, thr->num %d not NULL", thr->num);
thread_infos[thr->num] = thr;
LOCKRET(pthread_setspecific(thr_debug_key, thr));
if(check_locking_order)
open_lockorder(thr);
ret = thr->func(thr->arg);
thread_infos[thr->num] = NULL;
if(check_locking_order)
fclose(thr->order_info);
free(thr);
return ret;
}
/** check if OK, unlock */
void
checklock_unlock(enum check_lock_type type, struct checked_lock* lock,
const char* func, const char* file, int line)
{
struct thr_check *thr;
if(key_deleted)
return;
thr = (struct thr_check*)pthread_getspecific(thr_debug_key);
checktype(type, lock, func, file, line);
if(!thr) lock_error(lock, func, file, line, "no thread info");
acquire_locklock(lock, func, file, line);
/* was this thread even holding this lock? */
if(thr->holding_first != lock &&
lock->prev_held_lock[thr->num] == NULL) {
lock_error(lock, func, file, line, "unlock nonlocked lock");
}
if(lock->hold_count <= 0)
lock_error(lock, func, file, line, "too many unlocks");
/* store this point as last touched by */
lock->holder = thr;
lock->hold_count --;
lock->holder_func = func;
lock->holder_file = file;
lock->holder_line = line;
/* delete from thread holder list */
/* no need to lock other lockstructs, because they are all on the
* held-locks list, and this thread holds their locks.
* we only touch the thr->num members, so it is safe. */
if(thr->holding_first == lock)
thr->holding_first = lock->next_held_lock[thr->num];
if(thr->holding_last == lock)
thr->holding_last = lock->prev_held_lock[thr->num];
if(lock->next_held_lock[thr->num])
lock->next_held_lock[thr->num]->prev_held_lock[thr->num] =
lock->prev_held_lock[thr->num];
if(lock->prev_held_lock[thr->num])
lock->prev_held_lock[thr->num]->next_held_lock[thr->num] =
lock->next_held_lock[thr->num];
lock->next_held_lock[thr->num] = NULL;
lock->prev_held_lock[thr->num] = NULL;
if(type==check_lock_rwlock && lock->writeholder == thr) {
lock->writeholder = NULL;
prot_store(lock);
} else if(type != check_lock_rwlock) {
/* store memory areas that are protected, for later checks */
prot_store(lock);
}
LOCKRET(pthread_mutex_unlock(&lock->lock));
/* unlock it */
switch(type) {
case check_lock_mutex:
LOCKRET(pthread_mutex_unlock(&lock->u.mutex));
break;
case check_lock_spinlock:
LOCKRET(pthread_spin_unlock(&lock->u.spinlock));
break;
case check_lock_rwlock:
LOCKRET(pthread_rwlock_unlock(&lock->u.rwlock));
break;
default:
log_assert(0);
}
}
void* ub_thread_key_get(ub_thread_key_t key)
{
void* ret=NULL;
LOCKRET(thr_getspecific(key, &ret));
return ret;
}
