mq_notify: block all (application) signals in the worker thread

[musl] / src / aio / aio.c

diff --git a/src/aio/aio.c b/src/aio/aio.c
index e004f98..d7e063b 100644 (file)
--- a/src/aio/aio.c
+++ b/src/aio/aio.c
@@ -76,8 +76,14 @@ static struct aio_queue *****map;
 static volatile int aio_fd_cnt;
 volatile int __aio_fut;
 
+static size_t io_thread_stack_size;
+
+#define MAX(a,b) ((a)>(b) ? (a) : (b))
+
 static struct aio_queue *__aio_get_queue(int fd, int need)
 {
+       sigset_t allmask, origmask;
+       int masked = 0;
        if (fd < 0) {
                errno = EBADF;
                return 0;
@@ -89,7 +95,14 @@ static struct aio_queue *__aio_get_queue(int fd, int need)
        if ((!map || !map[a] || !map[a][b] || !map[a][b][c] || !(q=map[a][b][c][d])) && need) {
                pthread_rwlock_unlock(&maplock);
                if (fcntl(fd, F_GETFD) < 0) return 0;
+               sigfillset(&allmask);
+               masked = 1;
+               pthread_sigmask(SIG_BLOCK, &allmask, &origmask);
                pthread_rwlock_wrlock(&maplock);
+               if (!io_thread_stack_size) {
+                       unsigned long val = __getauxval(AT_MINSIGSTKSZ);
+                       io_thread_stack_size = MAX(MINSIGSTKSZ+2048, val+512);
+               }
                if (!map) map = calloc(sizeof *map, (-1U/2+1)>>24);
                if (!map) goto out;
                if (!map[a]) map[a] = calloc(sizeof **map, 256);
@@ -111,6 +124,7 @@ static struct aio_queue *__aio_get_queue(int fd, int need)
        if (q) pthread_mutex_lock(&q->lock);
 out:
        pthread_rwlock_unlock(&maplock);
+       if (masked) pthread_sigmask(SIG_SETMASK, &origmask, 0);
        return q;
 }
 
@@ -265,15 +279,6 @@ static void *io_thread_func(void *ctx)
        return 0;
 }
 
-static size_t io_thread_stack_size = MINSIGSTKSZ+2048;
-static pthread_once_t init_stack_size_once;
-
-static void init_stack_size()
-{
-       unsigned long val = __getauxval(AT_MINSIGSTKSZ);
-       if (val > MINSIGSTKSZ) io_thread_stack_size = val + 512;
-}
-
 static int submit(struct aiocb *cb, int op)
 {
        int ret = 0;
@@ -299,7 +304,6 @@ static int submit(struct aiocb *cb, int op)
                else
                        pthread_attr_init(&a);
        } else {
-               pthread_once(&init_stack_size_once, init_stack_size);
                pthread_attr_init(&a);
                pthread_attr_setstacksize(&a, io_thread_stack_size);
                pthread_attr_setguardsize(&a, 0);
@@ -403,18 +407,26 @@ void __aio_atfork(int who)
        if (who<0) {
                pthread_rwlock_rdlock(&maplock);
                return;
+       } else if (!who) {
+               pthread_rwlock_unlock(&maplock);
+               return;
        }
-       if (who>0 && map) for (int a=0; a<(-1U/2+1)>>24; a++)
+       aio_fd_cnt = 0;
+       if (pthread_rwlock_tryrdlock(&maplock)) {
+               /* Obtaining lock may fail if _Fork was called nor via
+                * fork. In this case, no further aio is possible from
+                * child and we can just null out map so __aio_close
+                * does not attempt to do anything. */
+               map = 0;
+               return;
+       }
+       if (map) for (int a=0; a<(-1U/2+1)>>24; a++)
                if (map[a]) for (int b=0; b<256; b++)
                        if (map[a][b]) for (int c=0; c<256; c++)
                                if (map[a][b][c]) for (int d=0; d<256; d++)
                                        map[a][b][c][d] = 0;
-       pthread_rwlock_unlock(&maplock);
+       /* Re-initialize the rwlock rather than unlocking since there
+        * may have been more than one reference on it in the parent.
+        * We are not a lock holder anyway; the thread in the parent was. */
+       pthread_rwlock_init(&maplock, 0);
 }
-
-weak_alias(aio_cancel, aio_cancel64);
-weak_alias(aio_error, aio_error64);
-weak_alias(aio_fsync, aio_fsync64);
-weak_alias(aio_read, aio_read64);
-weak_alias(aio_write, aio_write64);
-weak_alias(aio_return, aio_return64);