Add the filter expression to the enable_event agent protocol message

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

diff --git a/src/bin/lttng-sessiond/agent.c b/src/bin/lttng-sessiond/agent.c
index 33559c89a9423ea13b322d90c5db9995269d9f21..def13707bdf52fd40149dc0d9705393b4652b618 100644 (file)
--- a/src/bin/lttng-sessiond/agent.c
+++ b/src/bin/lttng-sessiond/agent.c
@@ -15,7 +15,6 @@
  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#define _GNU_SOURCE
 #define _LGPL_SOURCE
 #include <assert.h>
 #include <urcu/uatomic.h>
@@ -361,7 +360,9 @@ error:
 static int enable_event(struct agent_app *app, struct agent_event *event)
 {
        int ret;
+       char *bytes_to_send;
        uint64_t data_size;
+       size_t filter_expression_length;
        uint32_t reply_ret_code;
        struct lttcomm_agent_enable msg;
        struct lttcomm_agent_generic_reply reply;
@@ -373,7 +374,16 @@ static int enable_event(struct agent_app *app, struct agent_event *event)
        DBG2("Agent enabling event %s for app pid: %d and socket %d", event->name,
                        app->pid, app->sock->fd);
 
-       data_size = sizeof(msg);
+       /*
+        * Calculate the payload's size, which is the fixed-size struct followed
+        * by the variable-length filter expression (+1 for the ending \0).
+        */
+       if (!event->filter_expression) {
+               filter_expression_length = 0;
+       } else {
+               filter_expression_length = strlen(event->filter_expression) + 1;
+       }
+       data_size = sizeof(msg) + filter_expression_length;
 
        ret = send_header(app->sock, data_size, AGENT_CMD_ENABLE, 0);
        if (ret < 0) {
@@ -384,7 +394,22 @@ static int enable_event(struct agent_app *app, struct agent_event *event)
        msg.loglevel_value = event->loglevel_value;
        msg.loglevel_type = event->loglevel_type;
        strncpy(msg.name, event->name, sizeof(msg.name));
-       ret = send_payload(app->sock, &msg, sizeof(msg));
+       msg.filter_expression_length = filter_expression_length;
+
+       bytes_to_send = zmalloc(data_size);
+       if (!bytes_to_send) {
+               ret = LTTNG_ERR_NOMEM;
+               goto error;
+       }
+
+       memcpy(bytes_to_send, &msg, sizeof(msg));
+       if (filter_expression_length > 0) {
+               memcpy(bytes_to_send + sizeof(msg), event->filter_expression,
+                               filter_expression_length);
+       }
+
+       ret = send_payload(app->sock, bytes_to_send, data_size);
+       free(bytes_to_send);
        if (ret < 0) {
                goto error_io;
        }
@@ -874,46 +899,54 @@ void agent_add_event(struct agent_event *event, struct agent *agt)
 }
 
 /*
- * Find a agent event in the given agent using name.
+ * Find multiple agent events sharing the given name.
  *
- * RCU read side lock MUST be acquired.
+ * RCU read side lock MUST be acquired. It must be held for the
+ * duration of the iteration.
  *
- * Return object if found else NULL.
+ * Sets the given iterator.
  */
-struct agent_event *agent_find_event_by_name(const char *name,
-               struct agent *agt)
+void agent_find_events_by_name(const char *name, struct agent *agt,
+               struct lttng_ht_iter* iter)
 {
-       struct lttng_ht_node_str *node;
-       struct lttng_ht_iter iter;
        struct lttng_ht *ht;
        struct agent_ht_key key;
 
        assert(name);
        assert(agt);
        assert(agt->events);
+       assert(iter);
 
        ht = agt->events;
        key.name = name;
 
        cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
-                       ht_match_event_by_name, &key, &iter.iter);
-       node = lttng_ht_iter_get_node_str(&iter);
-       if (node == NULL) {
-               goto error;
-       }
+                       ht_match_event_by_name, &key, &iter->iter);
+}
 
-       DBG3("Agent event found %s by name.", name);
-       return caa_container_of(node, struct agent_event, node);
+/*
+ * Get the next agent event duplicate by name. This should be called
+ * after a call to agent_find_events_by_name() to iterate on events.
+ *
+ * The RCU read lock must be held during the iteration and for as long
+ * as the object the iterator points to remains in use.
+ */
+void agent_event_next_duplicate(const char *name,
+               struct agent *agt, struct lttng_ht_iter* iter)
+{
+       struct agent_ht_key key;
 
-error:
-       DBG3("Agent NOT found by name %s.", name);
-       return NULL;
+       key.name = name;
+
+       cds_lfht_next_duplicate(agt->events->ht, ht_match_event_by_name,
+               &key, &iter->iter);
 }
 
 /*
  * Find a agent event in the given agent using name and loglevel.
  *
- * RCU read side lock MUST be acquired.
+ * RCU read side lock MUST be acquired. It must be kept for as long as
+ * the returned agent_event is used.
  *
  * Return object if found else NULL.
  */