Fix: report error to client on consumerd error
[lttng-tools.git] / src / common / consumer.c
index 3d79b5122d82bb3f020f3efe920d86b93c493005..dd8c621f177d56968306fb500ce4546870b5bd2d 100644 (file)
@@ -2,24 +2,22 @@
  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; only version 2
- * of the License.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2 only,
+ * as published by the Free Software Foundation.
  *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
  *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #define _GNU_SOURCE
 #include <assert.h>
-#include <fcntl.h>
 #include <poll.h>
 #include <pthread.h>
 #include <stdlib.h>
@@ -300,11 +298,23 @@ end:
 int consumer_add_stream(struct lttng_consumer_stream *stream)
 {
        int ret = 0;
+       struct lttng_ht_node_ulong *node;
+       struct lttng_ht_iter iter;
 
        pthread_mutex_lock(&consumer_data.lock);
        /* Steal stream identifier, for UST */
        consumer_steal_stream_key(stream->key);
        rcu_read_lock();
+
+       lttng_ht_lookup(consumer_data.stream_ht,
+                       (void *)((unsigned long) stream->key), &iter);
+       node = lttng_ht_iter_get_node_ulong(&iter);
+       if (node != NULL) {
+               rcu_read_unlock();
+               /* Stream already exist. Ignore the insertion */
+               goto end;
+       }
+
        lttng_ht_add_unique_ulong(consumer_data.stream_ht, &stream->node);
        rcu_read_unlock();
        consumer_data.stream_count++;
@@ -468,11 +478,25 @@ end:
  */
 int consumer_add_channel(struct lttng_consumer_channel *channel)
 {
+       struct lttng_ht_node_ulong *node;
+       struct lttng_ht_iter iter;
+
        pthread_mutex_lock(&consumer_data.lock);
        /* Steal channel identifier, for UST */
        consumer_steal_channel_key(channel->key);
        rcu_read_lock();
+
+       lttng_ht_lookup(consumer_data.channel_ht,
+                       (void *)((unsigned long) channel->key), &iter);
+       node = lttng_ht_iter_get_node_ulong(&iter);
+       if (node != NULL) {
+               /* Channel already exist. Ignore the insertion */
+               goto end;
+       }
+
        lttng_ht_add_unique_ulong(consumer_data.channel_ht, &channel->node);
+
+end:
        rcu_read_unlock();
        pthread_mutex_unlock(&consumer_data.lock);
 
@@ -514,7 +538,7 @@ int consumer_update_poll_array(
         * increment i so nb_fd is the number of real FD.
         */
        (*pollfd)[i].fd = ctx->consumer_poll_pipe[0];
-       (*pollfd)[i].events = POLLIN;
+       (*pollfd)[i].events = POLLIN | POLLPRI;
        return i;
 }
 
@@ -538,7 +562,7 @@ restart:
                perror("Poll error");
                goto exit;
        }
-       if (consumer_sockpoll[0].revents == POLLIN) {
+       if (consumer_sockpoll[0].revents & (POLLIN | POLLPRI)) {
                DBG("consumer_should_quit wake up");
                goto exit;
        }
@@ -612,6 +636,9 @@ void lttng_consumer_cleanup(void)
        }
 
        rcu_read_unlock();
+
+       lttng_ht_destroy(consumer_data.stream_ht);
+       lttng_ht_destroy(consumer_data.channel_ht);
 }
 
 /*
@@ -641,7 +668,7 @@ void lttng_consumer_sync_trace_file(
        if (orig_offset < stream->chan->max_sb_size) {
                return;
        }
-       sync_file_range(outfd, orig_offset - stream->chan->max_sb_size,
+       lttng_sync_file_range(outfd, orig_offset - stream->chan->max_sb_size,
                        stream->chan->max_sb_size,
                        SYNC_FILE_RANGE_WAIT_BEFORE
                        | SYNC_FILE_RANGE_WRITE
@@ -712,6 +739,20 @@ struct lttng_consumer_local_data *lttng_consumer_create(
                goto error_poll_pipe;
        }
 
+       /* set read end of the pipe to non-blocking */
+       ret = fcntl(ctx->consumer_poll_pipe[0], F_SETFL, O_NONBLOCK);
+       if (ret < 0) {
+               perror("fcntl O_NONBLOCK");
+               goto error_poll_fcntl;
+       }
+
+       /* set write end of the pipe to non-blocking */
+       ret = fcntl(ctx->consumer_poll_pipe[1], F_SETFL, O_NONBLOCK);
+       if (ret < 0) {
+               perror("fcntl O_NONBLOCK");
+               goto error_poll_fcntl;
+       }
+
        ret = pipe(ctx->consumer_should_quit);
        if (ret < 0) {
                perror("Error creating recv pipe");
@@ -736,6 +777,7 @@ error_thread_pipe:
                        PERROR("close");
                }
        }
+error_poll_fcntl:
 error_quit_pipe:
        for (i = 0; i < 2; i++) {
                int err;
@@ -809,6 +851,8 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
                ERR("Unknown consumer_data type");
                assert(0);
        }
+
+       return 0;
 }
 
 /*
@@ -907,8 +951,6 @@ void *lttng_consumer_thread_poll_fds(void *data)
        struct lttng_consumer_stream **local_stream = NULL;
        /* local view of consumer_data.fds_count */
        int nb_fd = 0;
-       char tmp;
-       int tmp2;
        struct lttng_consumer_local_data *ctx = data;
 
        rcu_register_thread();
@@ -992,12 +1034,15 @@ void *lttng_consumer_thread_poll_fds(void *data)
                 * array. We want to prioritize array update over
                 * low-priority reads.
                 */
-               if (pollfd[nb_fd].revents & POLLIN) {
+               if (pollfd[nb_fd].revents & (POLLIN | POLLPRI)) {
+                       size_t pipe_readlen;
+                       char tmp;
+
                        DBG("consumer_poll_pipe wake up");
-                       tmp2 = read(ctx->consumer_poll_pipe[0], &tmp, 1);
-                       if (tmp2 < 0) {
-                               perror("read consumer poll");
-                       }
+                       /* Consume 1 byte of pipe data */
+                       do {
+                               pipe_readlen = read(ctx->consumer_poll_pipe[0], &tmp, 1);
+                       } while (pipe_readlen == -1 && errno == EINTR);
                        continue;
                }
 
@@ -1202,11 +1247,20 @@ end:
         */
        consumer_poll_timeout = LTTNG_CONSUMER_POLL_TIMEOUT;
 
-       /* wake up the polling thread */
-       ret = write(ctx->consumer_poll_pipe[1], "4", 1);
-       if (ret < 0) {
-               perror("poll pipe write");
-       }
+       /*
+        * Wake-up the other end by writing a null byte in the pipe
+        * (non-blocking). Important note: Because writing into the
+        * pipe is non-blocking (and therefore we allow dropping wakeup
+        * data, as long as there is wakeup data present in the pipe
+        * buffer to wake up the other end), the other end should
+        * perform the following sequence for waiting:
+        * 1) empty the pipe (reads).
+        * 2) perform update operation.
+        * 3) wait on the pipe (poll).
+        */
+       do {
+               ret = write(ctx->consumer_poll_pipe[1], "", 1);
+       } while (ret == -1UL && errno == EINTR);
        rcu_unregister_thread();
        return NULL;
 }
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