Fix: handle backward compatibility with lttng-modules 2.7

[lttng-tools.git] / src / common / kernel-consumer / kernel-consumer.c

diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index e5c0c2e83a3930e1079ef96d056767b64893a7c7..f89ab1a6e29adf8803c9e6158cd359fab72eb4f5 100644 (file)
--- a/src/common/kernel-consumer/kernel-consumer.c
+++ b/src/common/kernel-consumer/kernel-consumer.c
@@ -118,7 +118,6 @@ int lttng_kconsumer_snapshot_channel(uint64_t key, char *path,
                struct lttng_consumer_local_data *ctx)
 {
        int ret;
-       unsigned long consumed_pos, produced_pos;
        struct lttng_consumer_channel *channel;
        struct lttng_consumer_stream *stream;
 
@@ -143,6 +142,7 @@ int lttng_kconsumer_snapshot_channel(uint64_t key, char *path,
        cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
                /* Are we at a position _before_ the first available packet ? */
                bool before_first_packet = true;
+               unsigned long consumed_pos, produced_pos;
 
                health_code_update();
 
@@ -969,18 +969,18 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                uint64_t id = msg.u.discarded_events.session_id;
                uint64_t key = msg.u.discarded_events.channel_key;
 
+               DBG("Kernel consumer discarded events command for session id %"
+                               PRIu64 ", channel key %" PRIu64, id, key);
+
                channel = consumer_find_channel(key);
                if (!channel) {
                        ERR("Kernel consumer discarded events channel %"
                                        PRIu64 " not found", key);
-                       ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
+                       ret = 0;
+               } else {
+                       ret = channel->discarded_events;
                }
 
-               DBG("Kernel consumer discarded events command for session id %"
-                               PRIu64 ", channel key %" PRIu64, id, key);
-
-               ret = channel->discarded_events;
-
                health_code_update();
 
                /* Send back returned value to session daemon */
@@ -999,18 +999,18 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                uint64_t id = msg.u.lost_packets.session_id;
                uint64_t key = msg.u.lost_packets.channel_key;
 
+               DBG("Kernel consumer lost packets command for session id %"
+                               PRIu64 ", channel key %" PRIu64, id, key);
+
                channel = consumer_find_channel(key);
                if (!channel) {
                        ERR("Kernel consumer lost packets channel %"
                                        PRIu64 " not found", key);
-                       ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
+                       ret = 0;
+               } else {
+                       ret = channel->lost_packets;
                }
 
-               DBG("Kernel consumer lost packets command for session id %"
-                               PRIu64 ", channel key %" PRIu64, id, key);
-
-               ret = channel->lost_packets;
-
                health_code_update();
 
                /* Send back returned value to session daemon */
@@ -1095,15 +1095,27 @@ static int get_index_values(struct ctf_packet_index *index, int infd)
 
        ret = kernctl_get_instance_id(infd, &index->stream_instance_id);
        if (ret < 0) {
-               PERROR("kernctl_get_instance_id");
-               goto error;
+               if (ret == -ENOTTY) {
+                       /* Command not implemented by lttng-modules. */
+                       index->stream_instance_id = -1ULL;
+                       ret = 0;
+               } else {
+                       PERROR("kernctl_get_instance_id");
+                       goto error;
+               }
        }
        index->stream_instance_id = htobe64(index->stream_instance_id);
 
        ret = kernctl_get_sequence_number(infd, &index->packet_seq_num);
        if (ret < 0) {
-               PERROR("kernctl_get_sequence_number");
-               goto error;
+               if (ret == -ENOTTY) {
+                       /* Command not implemented by lttng-modules. */
+                       index->packet_seq_num = -1ULL;
+                       ret = 0;
+               } else {
+                       PERROR("kernctl_get_sequence_number");
+                       goto error;
+               }
        }
        index->packet_seq_num = htobe64(index->packet_seq_num);
 
@@ -1155,8 +1167,14 @@ int update_stream_stats(struct lttng_consumer_stream *stream)
 
        ret = kernctl_get_sequence_number(stream->wait_fd, &seq);
        if (ret < 0) {
-               PERROR("kernctl_get_sequence_number");
-               goto end;
+               if (ret == -ENOTTY) {
+                       /* Command not implemented by lttng-modules. */
+                       seq = -1ULL;
+                       ret = 0;
+               } else {
+                       PERROR("kernctl_get_sequence_number");
+                       goto end;
+               }
        }
 
        /*
@@ -1186,8 +1204,8 @@ int update_stream_stats(struct lttng_consumer_stream *stream)
        }
        if (discarded < stream->last_discarded_events) {
                /*
-                * Overflow has occured. We assume only one wrap-around
-                * has occured.
+                * Overflow has occurred. We assume only one wrap-around
+                * has occurred.
                 */
                stream->chan->discarded_events += (1ULL << (CAA_BITS_PER_LONG - 1)) -
                        stream->last_discarded_events + discarded;
@@ -1202,6 +1220,45 @@ end:
        return ret;
 }
 
+/*
+ * Check if the local version of the metadata stream matches with the version
+ * of the metadata stream in the kernel. If it was updated, set the reset flag
+ * on the stream.
+ */
+static
+int metadata_stream_check_version(int infd, struct lttng_consumer_stream *stream)
+{
+       int ret;
+       uint64_t cur_version;
+
+       ret = kernctl_get_metadata_version(infd, &cur_version);
+       if (ret < 0) {
+               if (ret == -ENOTTY) {
+                       /*
+                        * LTTng-modules does not implement this
+                        * command.
+                        */
+                       ret = 0;
+                       goto end;
+               }
+               ERR("Failed to get the metadata version");
+               goto end;
+       }
+
+       if (stream->metadata_version == cur_version) {
+               ret = 0;
+               goto end;
+       }
+
+       DBG("New metadata version detected");
+       stream->metadata_version = cur_version;
+       stream->reset_metadata_flag = 1;
+       ret = 0;
+
+end:
+       return ret;
+}
+
 /*
  * Consume data on a file descriptor and write it on a trace file.
  */
@@ -1272,6 +1329,10 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                }
        } else {
                write_index = 0;
+               ret = metadata_stream_check_version(infd, stream);
+               if (ret < 0) {
+                       goto end;
+               }
        }
 
        switch (stream->chan->output) {