ao_write: Avoid segfault on exit.

[paraslash.git] / ao_write.c

diff --git a/ao_write.c b/ao_write.c
index fdae8eea542f97720f963f281bddd121cf5d0a38..12ab77fe8dc33c1b5be189eff6bd4621cb4305a6 100644 (file)
--- a/ao_write.c
+++ b/ao_write.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2011-2013 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2011-2014 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -39,6 +39,10 @@ static void aow_close(struct writer_node *wn)
 
        if (!pawd)
                return;
+       if (pawd->thread_btrn) {
+               pthread_cancel(pawd->thread);
+               pthread_join(pawd->thread, NULL);
+       }
        ao_close(pawd->dev);
        free(pawd);
        wn->private_data = NULL;
@@ -48,10 +52,37 @@ static void aow_close(struct writer_node *wn)
 static void aow_pre_select(struct sched *s, struct task *t)
 {
        struct writer_node *wn = container_of(t, struct writer_node, task);
-       int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
+       struct private_aow_data *pawd = wn->private_data;
+       int ret;
 
-       if (ret == 0)
-               return;
+       if (!pawd) { /* not yet started */
+               assert(wn->btrn);
+               ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
+               if (ret != 0)
+                       goto min_delay;
+               return; /* no data available */
+       }
+       if (!wn->btrn) { /* EOF */
+               if (!pawd->thread_btrn) /* ready to exit */
+                       goto min_delay;
+               /* wait for the play thread to terminate */
+               goto timeout;
+       }
+       pthread_mutex_lock(&pawd->mutex);
+       ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
+       pthread_mutex_unlock(&pawd->mutex);
+       if (ret != 0)
+               goto min_delay;
+       /*
+        * Even though the node status is zero, we might have data available,
+        * but the output buffer is full. If we don't set a timeout here, we
+        * are woken up only if new data arrives, which might be too late and
+        * result in a buffer underrun in the playing thread. To avoid this we
+        * never sleep longer than the (default) buffer time.
+        */
+timeout:
+       return sched_request_timeout_ms(20, s);
+min_delay:
        sched_min_delay(s);
 }
 
@@ -223,13 +254,16 @@ __noreturn static void *aow_play(void *priv)
                ret = -E_AO_PLAY;
                if (ao_play(pawd->dev, data, bytes) == 0) /* failure */
                        goto out;
+               pthread_mutex_lock(&pawd->mutex);
                btr_consume(btrn, bytes);
+               pthread_mutex_unlock(&pawd->mutex);
        }
 unlock:
        pthread_mutex_unlock(&pawd->mutex);
 out:
        assert(ret < 0);
        PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
+       btr_remove_node(&pawd->thread_btrn);
        pthread_exit(NULL);
 }
 
@@ -314,6 +348,12 @@ static int aow_post_select(__a_unused struct sched *s,
                        goto remove_thread_btrn;
                return 0;
        }
+       if (!wn->btrn) {
+               if (!pawd->thread_btrn)
+                       return -E_AO_EOF;
+               PARA_INFO_LOG("waiting for play thread to terminate\n");
+               return 0;
+       }
        pthread_mutex_lock(&pawd->mutex);
        ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
        if (ret > 0) {
@@ -325,10 +365,9 @@ static int aow_post_select(__a_unused struct sched *s,
                goto out;
        pthread_mutex_lock(&pawd->mutex);
        btr_remove_node(&wn->btrn);
-       PARA_INFO_LOG("waiting for thread to terminate\n");
        pthread_cond_signal(&pawd->data_available);
        pthread_mutex_unlock(&pawd->mutex);
-       pthread_join(pawd->thread, NULL);
+       return 0;
 remove_thread_btrn:
        btr_remove_node(&pawd->thread_btrn);
 remove_btrn: