Fix: poll: show the correct number of fds

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

diff --git a/src/bin/lttng-sessiond/agent-thread.c b/src/bin/lttng-sessiond/agent-thread.c
index da0171ba0afadf7ff883b7545e823b3dab346c48..5f4815165fed49c113a8e9ce875c5a374890b7c6 100644 (file)
--- a/src/bin/lttng-sessiond/agent-thread.c
+++ b/src/bin/lttng-sessiond/agent-thread.c
@@ -16,6 +16,7 @@
  */
 
 #define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <assert.h>
 
 #include <common/common.h>
@@ -46,7 +47,7 @@ static const char *default_reg_uri =
  * This is a quite heavy call in terms of locking since the session list lock
  * AND session lock are acquired.
  */
-static void update_agent_app(int sock)
+static void update_agent_app(struct agent_app *app)
 {
        struct ltt_session *session, *stmp;
        struct ltt_session_list *list;
@@ -58,7 +59,14 @@ static void update_agent_app(int sock)
        cds_list_for_each_entry_safe(session, stmp, &list->head, list) {
                session_lock(session);
                if (session->ust_session) {
-                       agent_update(&session->ust_session->agent, sock);
+                       struct agent *agt;
+
+                       rcu_read_lock();
+                       agt = trace_ust_find_agent(session->ust_session, app->domain);
+                       if (agt) {
+                               agent_update(agt, app->sock->fd);
+                       }
+                       rcu_read_unlock();
                }
                session_unlock(session);
        }
@@ -193,7 +201,9 @@ static int handle_registration(struct lttcomm_sock *reg_sock,
 {
        int ret;
        pid_t pid;
+       uint32_t major_version, minor_version;
        ssize_t size;
+       enum lttng_domain_type domain;
        struct agent_app *app;
        struct agent_register_msg msg;
        struct lttcomm_sock *new_sock;
@@ -208,15 +218,28 @@ static int handle_registration(struct lttcomm_sock *reg_sock,
 
        size = new_sock->ops->recvmsg(new_sock, &msg, sizeof(msg), 0);
        if (size < sizeof(msg)) {
-               ret = -errno;
+               ret = -EINVAL;
                goto error_socket;
        }
+       domain = be32toh(msg.domain);
        pid = be32toh(msg.pid);
+       major_version = be32toh(msg.major_version);
+       minor_version = be32toh(msg.minor_version);
 
-       DBG2("[agent-thread] New registration for pid %d on socket %d", pid,
-                       new_sock->fd);
+       /* Test communication protocol version of the registring agent. */
+       if (major_version != AGENT_MAJOR_VERSION) {
+               ret = -EINVAL;
+               goto error_socket;
+       }
+       if (minor_version != AGENT_MINOR_VERSION) {
+               ret = -EINVAL;
+               goto error_socket;
+       }
 
-       app = agent_create_app(pid, new_sock);
+       DBG2("[agent-thread] New registration for pid %d domain %d on socket %d",
+                       pid, domain, new_sock->fd);
+
+       app = agent_create_app(pid, domain, new_sock);
        if (!app) {
                ret = -ENOMEM;
                goto error_socket;
@@ -284,12 +307,14 @@ void *agent_thread_manage_registration(void *data)
        }
 
        while (1) {
-               DBG3("[agent-thread] Manage agent polling on %d fds",
+               DBG3("[agent-thread] Manage agent polling",
                                LTTNG_POLL_GETNB(&events));
 
                /* Inifinite blocking call, waiting for transmission */
 restart:
                ret = lttng_poll_wait(&events, -1);
+               DBG3("[agent-thread] Manage agent return from poll on %d fds",
+                               LTTNG_POLL_GETNB(&events));
                if (ret < 0) {
                        /*
                         * Restart interrupted system call.
@@ -307,6 +332,11 @@ restart:
                        revents = LTTNG_POLL_GETEV(&events, i);
                        pollfd = LTTNG_POLL_GETFD(&events, i);
 
+                       if (!revents) {
+                               /* No activity for this FD (poll implementation). */
+                               continue;
+                       }
+
                        /* Thread quit pipe has been closed. Killing thread. */
                        ret = sessiond_check_thread_quit_pipe(pollfd, revents);
                        if (ret) {
@@ -350,7 +380,7 @@ restart:
                                }
 
                                /* Update newly registered app. */
-                               update_agent_app(new_fd);
+                               update_agent_app(app);
 
                                /* On failure, the poll will detect it and clean it up. */
                                (void) agent_send_registration_done(app);