Fix: lttng list of channels should return errors

[lttng-tools.git] / src / bin / lttng-sessiond / cmd.c

diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index 325ffd2cf14f6ec3e320e402e8db17a6dac71adc..fb5f19bdbab6cb19ddc2d07466750a36e1366a9c 100644 (file)
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -235,11 +235,11 @@ end:
 /*
  * Fill lttng_channel array of all channels.
  */
-static void list_lttng_channels(enum lttng_domain_type domain,
+static ssize_t list_lttng_channels(enum lttng_domain_type domain,
                struct ltt_session *session, struct lttng_channel *channels,
                struct lttcomm_channel_extended *chan_exts)
 {
-       int i = 0, ret;
+       int i = 0, ret = 0;
        struct ltt_kernel_channel *kchan;
 
        DBG("Listing channels for session %s", session->name);
@@ -325,7 +325,11 @@ static void list_lttng_channels(enum lttng_domain_type domain,
        }
 
 end:
-       return;
+       if (ret < 0) {
+               return -LTTNG_ERR_FATAL;
+       } else {
+               return LTTNG_OK;
+       }
 }
 
 static void increment_extended_len(const char *filter_expression,
@@ -2952,7 +2956,12 @@ ssize_t cmd_list_channels(enum lttng_domain_type domain,
 
                channel_exts = ((void *) *channels) +
                                (nb_chan * sizeof(struct lttng_channel));
-               list_lttng_channels(domain, session, *channels, channel_exts);
+               ret = list_lttng_channels(domain, session, *channels, channel_exts);
+               if (ret != LTTNG_OK) {
+                       free(*channels);
+                       *channels = NULL;
+                       goto end;
+               }
        } else {
                *channels = NULL;
        }
@@ -3377,6 +3386,27 @@ end:
        return ret;
 }
 
+static
+int clear_metadata_file(int fd)
+{
+       int ret;
+
+       ret = lseek(fd, 0, SEEK_SET);
+       if (ret < 0) {
+               PERROR("lseek");
+               goto end;
+       }
+
+       ret = ftruncate(fd, 0);
+       if (ret < 0) {
+               PERROR("ftruncate");
+               goto end;
+       }
+
+end:
+       return ret;
+}
+
 static
 int ust_regenerate_metadata(struct ltt_ust_session *usess)
 {
@@ -3398,6 +3428,15 @@ int ust_regenerate_metadata(struct ltt_ust_session *usess)
                memset(registry->metadata, 0, registry->metadata_alloc_len);
                registry->metadata_len = 0;
                registry->metadata_version++;
+               if (registry->metadata_fd > 0) {
+                       /* Clear the metadata file's content. */
+                       ret = clear_metadata_file(registry->metadata_fd);
+                       if (ret) {
+                               pthread_mutex_unlock(&registry->lock);
+                               goto end;
+                       }
+               }
+
                ret = ust_metadata_session_statedump(registry, NULL,
                                registry->major, registry->minor);
                if (ret) {