mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-06-27 14:58:30 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Make detached threads work better

Browse source 
This change adds a double linked list of threads, so that pthread_exit()
will know when it should call exit() from an orphaned child. This change
also improves ftrace and strace logging.
This commit is contained in:
Justine Tunney 2022-11-09 03:58:57 -08:00
parent b74d8c1acd
commit cee6871710
No known key found for this signature in database
GPG key ID: BE714B4575D6E328
37 changed files with 638 additions and 314 deletions
Download patch file Download diff file Expand all files Collapse all files

29
libc/thread/pthread_detach.c
View file

@ -16,45 +16,52 @@
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/errno.h"
#include "libc/intrin/atomic.h"
#include "libc/intrin/strace.internal.h"
#include "libc/macros.internal.h"
#include "libc/mem/mem.h"
#include "libc/thread/posixthread.internal.h"
#include "libc/thread/spawn.h"
#include "libc/thread/thread.h"
#include "third_party/nsync/dll.h"
/**
* Asks POSIX thread to free itself automatically on termination.
* Asks POSIX thread to free itself automatically upon termination.
*
* If this function is used, then it's important to use pthread_exit()
* rather than exit() since otherwise your program isn't guaranteed to
* gracefully terminate.
*
* Detaching a non-joinable thread is undefined behavior. For example,
* pthread_detach() can't be called twice on the same thread.
*
* @return 0 on success, or errno with error
* @raise EINVAL if thread is null or already detached
* @returnserrno
* @threadsafe
*/
errno_t pthread_detach(pthread_t thread) {
struct PosixThread *pt;
enum PosixThreadStatus status, transition;
if (!(pt = (struct PosixThread *)thread)) return EINVAL;
for (;;) {
for (pt = (struct PosixThread *)thread;;) {
status = atomic_load_explicit(&pt->status, memory_order_acquire);
if (status == kPosixThreadDetached || status == kPosixThreadZombie) {
// these two states indicate the thread was already detached, in
// which case it's already listed under _pthread_zombies.
return EINVAL;
} else if (status == kPosixThreadJoinable) {
if (status == kPosixThreadJoinable) {
transition = kPosixThreadDetached;
} else if (status == kPosixThreadTerminated) {
transition = kPosixThreadZombie;
} else {
notpossible;
unreachable;
}
if (atomic_compare_exchange_weak_explicit(&pt->status, &status, transition,
memory_order_release,
memory_order_relaxed)) {
_pthread_zombies_add(pt);
break;
}
}
if (transition == kPosixThreadZombie) {
_pthread_zombify(pt);
}
pthread_decimate_np();
return 0;
}