More hacking around spawn_func issues

This time, we use a pthread_attr to make sure that if pthread_create
succeeds, the thread is successfully detached.

This probably isn't the big thing going on with 4345, since it'd be
a bit weird for pthread_detach to be failing.  But it's worth
getting it right.
This commit is contained in:
Nick Mathewson 2014-02-07 13:13:15 -05:00
parent 85b46d57bc
commit 1ebdaf5788
2 changed files with 16 additions and 6 deletions

View File

@ -1,6 +1,10 @@
o Minor bugfixes:
- Check return code on spawn_func() in cpuworker code, so that we don't
think we've spawned a nonworking cpuworker and write junk to it
forever. Fix for bug 4345; bugfix on all released Tor versions.
forever. Fix related to bug 4345; bugfix on all released Tor versions.
Found by "skruffy".
- Use a pthread_attr to make sure that spawn_func() cannot return
an error while at the same time launching a thread. Fix related
to bug 4345; bugfix on all released Tor versions. Reported by
"cypherpunks".

View File

@ -2248,6 +2248,12 @@ tor_pthread_helper_fn(void *_data)
func(arg);
return NULL;
}
/**
* A pthread attribute to make threads start detached.
*/
static pthread_attr_t attr_detached;
/** True iff we've called tor_threads_init() */
static int threads_initialized = 0;
#endif
/** Minimalist interface to run a void function in the background. On
@ -2271,12 +2277,12 @@ spawn_func(void (*func)(void *), void *data)
#elif defined(USE_PTHREADS)
pthread_t thread;
tor_pthread_data_t *d;
if (PREDICT_UNLIKELY(!threads_initialized))
tor_threads_init();
d = tor_malloc(sizeof(tor_pthread_data_t));
d->data = data;
d->func = func;
if (pthread_create(&thread,NULL,tor_pthread_helper_fn,d))
return -1;
if (pthread_detach(thread))
if (pthread_create(&thread,&attr_detached,tor_pthread_helper_fn,d))
return -1;
return 0;
#else
@ -2633,8 +2639,6 @@ tor_get_thread_id(void)
* "reentrant" mutexes (i.e., once we can re-lock if we're already holding
* them.) */
static pthread_mutexattr_t attr_reentrant;
/** True iff we've called tor_threads_init() */
static int threads_initialized = 0;
/** Initialize <b>mutex</b> so it can be locked. Every mutex must be set
* up with tor_mutex_init() or tor_mutex_new(); not both. */
void
@ -2778,6 +2782,8 @@ tor_threads_init(void)
if (!threads_initialized) {
pthread_mutexattr_init(&attr_reentrant);
pthread_mutexattr_settype(&attr_reentrant, PTHREAD_MUTEX_RECURSIVE);
tor_assert(0==pthread_attr_init(&attr_detached));
tor_assert(0==pthread_attr_setdetachstate(&attr_detached, 1));
threads_initialized = 1;
set_main_thread();
}