Fix multi-session UST handling combined with shm fd teardown

[lttng-tools.git] / liblttng-consumer / lttng-consumer.c

diff --git a/liblttng-consumer/lttng-consumer.c b/liblttng-consumer/lttng-consumer.c
index c7c7b7a7e4db220f8cbb512cb976746213e24dbe..293d5f808ea0d2f68d441554563b239911fd02b8 100644 (file)
--- a/liblttng-consumer/lttng-consumer.c
+++ b/liblttng-consumer/lttng-consumer.c
@@ -63,6 +63,9 @@ static struct lttng_consumer_stream *consumer_find_stream(int key)
 {
        struct lttng_consumer_stream *iter;
 
+       /* Negative keys are lookup failures */
+       if (key < 0)
+               return NULL;
        cds_list_for_each_entry(iter, &consumer_data.stream_list.head, list) {
                if (iter->key == key) {
                        DBG("Found stream key %d", key);
@@ -72,10 +75,22 @@ static struct lttng_consumer_stream *consumer_find_stream(int key)
        return NULL;
 }
 
+static void consumer_steal_stream_key(int key)
+{
+       struct lttng_consumer_stream *stream;
+
+       stream = consumer_find_stream(key);
+       if (stream)
+               stream->key = -1;
+}
+
 static struct lttng_consumer_channel *consumer_find_channel(int key)
 {
        struct lttng_consumer_channel *iter;
 
+       /* Negative keys are lookup failures */
+       if (key < 0)
+               return NULL;
        cds_list_for_each_entry(iter, &consumer_data.channel_list.head, list) {
                if (iter->key == key) {
                        DBG("Found channel key %d", key);
@@ -85,6 +100,15 @@ static struct lttng_consumer_channel *consumer_find_channel(int key)
        return NULL;
 }
 
+static void consumer_steal_channel_key(int key)
+{
+       struct lttng_consumer_channel *channel;
+
+       channel = consumer_find_channel(key);
+       if (channel)
+               channel->key = -1;
+}
+
 /*
  * Remove a stream from the global list protected by a mutex. This
  * function is also responsible for freeing its data structures.
@@ -211,11 +235,8 @@ int consumer_add_stream(struct lttng_consumer_stream *stream)
        int ret = 0;
 
        pthread_mutex_lock(&consumer_data.lock);
-       /* Check if already exist */
-       if (consumer_find_stream(stream->key)) {
-               ret = -1;
-               goto end;
-       }
+       /* Steal stream identifier, for UST */
+       consumer_steal_stream_key(stream->key);
        cds_list_add(&stream->list, &consumer_data.stream_list.head);
        consumer_data.stream_count++;
        consumer_data.need_update = 1;
@@ -350,18 +371,12 @@ end:
  */
 int consumer_add_channel(struct lttng_consumer_channel *channel)
 {
-       int ret = 0;
-
        pthread_mutex_lock(&consumer_data.lock);
-       /* Check if already exist */
-       if (consumer_find_channel(channel->key)) {
-               ret = -1;
-               goto end;
-       }
+       /* Steal channel identifier, for UST */
+       consumer_steal_channel_key(channel->key);
        cds_list_add(&channel->list, &consumer_data.channel_list.head);
-end:
        pthread_mutex_unlock(&consumer_data.lock);
-       return ret;
+       return 0;
 }
 
 /*