Implement --shm-path option for UST sessions (per-uid channels)

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

diff --git a/src/bin/lttng-sessiond/ust-consumer.c b/src/bin/lttng-sessiond/ust-consumer.c
index 611b54dcdb17d392f14bd42dc98320a0cb098b61..8a3533ba10c360097a8fb2cb0099a4f3d986f324 100644 (file)
--- a/src/bin/lttng-sessiond/ust-consumer.c
+++ b/src/bin/lttng-sessiond/ust-consumer.c
@@ -109,6 +109,7 @@ static int ask_channel_creation(struct ust_app_session *ua_sess,
        char *pathname = NULL;
        struct lttcomm_consumer_msg msg;
        struct ust_registry_channel *chan_reg;
+       char shm_path[PATH_MAX] = "";
 
        assert(ua_sess);
        assert(ua_chan);
@@ -136,10 +137,25 @@ static int ask_channel_creation(struct ust_app_session *ua_sess,
 
        if (ua_chan->attr.type == LTTNG_UST_CHAN_METADATA) {
                chan_id = -1U;
+               /*
+                * Metadata channels shm_path (buffers) are handled within
+                * session daemon. Consumer daemon should not try to create
+                * those buffer files.
+                */
        } else {
                chan_reg = ust_registry_channel_find(registry, chan_reg_key);
                assert(chan_reg);
                chan_id = chan_reg->chan_id;
+               if (ua_sess->shm_path[0]) {
+                       strncpy(shm_path, ua_sess->shm_path, sizeof(shm_path));
+                       shm_path[sizeof(shm_path) - 1] = '\0';
+                       strncat(shm_path, "/",
+                               sizeof(shm_path) - strlen(shm_path) - 1);
+                       strncat(shm_path, ua_chan->name,
+                                       sizeof(shm_path) - strlen(shm_path) - 1);
+                               strncat(shm_path, "_",
+                                       sizeof(shm_path) - strlen(shm_path) - 1);
+               }
        }
 
        switch (ua_chan->attr.output) {
@@ -171,7 +187,8 @@ static int ask_channel_creation(struct ust_app_session *ua_sess,
                        ua_chan->tracefile_count,
                        ua_sess->id,
                        ua_sess->output_traces,
-                       ua_sess->uid);
+                       ua_sess->uid,
+                       shm_path);
 
        health_code_update();