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 6790a63c642bd78bb37484a6c6af0b1af39081c7..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>
@@ -60,10 +61,12 @@ static void update_agent_app(struct agent_app *app)
                if (session->ust_session) {
                        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);
        }
@@ -198,6 +201,7 @@ 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;
@@ -214,11 +218,23 @@ 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);
+
+       /* 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;
+       }
 
        DBG2("[agent-thread] New registration for pid %d domain %d on socket %d",
                        pid, domain, new_sock->fd);
@@ -291,12 +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.
@@ -314,6 +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) {