Add a safety check to nbfd of apps cmd pollfd

[lttng-tools.git] / ltt-sessiond / main.c

diff --git a/ltt-sessiond/main.c b/ltt-sessiond/main.c
index 85ac06be9e32c2967417513b7902d2b226b303ba..436ee9f167e8a45853fe9b58557555de74b82629 100644 (file)
--- a/ltt-sessiond/main.c
+++ b/ltt-sessiond/main.c
@@ -880,6 +880,15 @@ static int update_apps_cmd_pollfd(unsigned int nb_fd, unsigned int old_nb_fd,
                }
        }
 
+       if (nb_fd < 2) {
+               /*
+                * There should *always* be at least two fds in the pollfd. This safety
+                * check make sure the poll() will actually try on those two pipes at
+                * best which are the thread_quit_pipe and apps_cmd_pipe.
+                */
+               nb_fd = 2;
+       }
+
        /* Destroy old pollfd */
        free(old_pollfd);
 
@@ -899,7 +908,7 @@ error:
  */
 static void *thread_manage_apps(void *data)
 {
-       int i, ret, count;
+       int i, ret, current_nb_fd;
        unsigned int nb_fd = 2;
        int update_poll_flag = 1;
        struct pollfd *pollfd = NULL;
@@ -908,6 +917,7 @@ static void *thread_manage_apps(void *data)
        DBG("[thread] Manage application started");
 
        ust_cmd.sock = -1;
+       current_nb_fd = nb_fd;
 
        while (1) {
                /* See if we have a valid socket to add to pollfd */
@@ -918,7 +928,7 @@ static void *thread_manage_apps(void *data)
 
                /* The pollfd struct must be updated */
                if (update_poll_flag) {
-                       ret = update_apps_cmd_pollfd(nb_fd, ARRAY_SIZE(pollfd), &pollfd);
+                       ret = update_apps_cmd_pollfd(nb_fd, current_nb_fd, &pollfd);
                        if (ret < 0) {
                                /* malloc failed so we quit */
                                goto error;
@@ -978,8 +988,8 @@ static void *thread_manage_apps(void *data)
                        }
                }
 
-               count = nb_fd;
-               for (i = 2; i < count; i++) {
+               current_nb_fd = nb_fd;
+               for (i = 2; i < current_nb_fd; i++) {
                        /* Apps socket is closed/hungup */
                        switch (pollfd[i].revents) {
                        case POLLERR:
@@ -994,7 +1004,7 @@ static void *thread_manage_apps(void *data)
                        }
                }
 
-               if (nb_fd != count) {
+               if (nb_fd != current_nb_fd) {
                        update_poll_flag = 1;
                }
        }