Fix: main.c client/apps sockets and kernel_trace_fd close(0)

thread_registration_apps and thread_manage_clients threads are closing
sock == 0 in error handling path, which is an error.

They also may use kernel_tracer_fd at 0 value if no kernel tracer has
been found. cleanup() can close this 0 socket too, which should never
happen.

Set all these sockets as "-1" when unset.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
index 3cb970c06e21c62c50b42a2e7466ead067a493f9..efe2143ddcb101065200b040a5e3f7309ba31491 100644 (file)
--- a/src/bin/lttng-sessiond/main.c
+++ b/src/bin/lttng-sessiond/main.c
@@ -122,9 +122,9 @@ static char client_unix_sock_path[PATH_MAX];
 static char wait_shm_path[PATH_MAX];
 
 /* Sockets and FDs */
-static int client_sock;
-static int apps_sock;
-static int kernel_tracer_fd;
+static int client_sock = -1;
+static int apps_sock = -1;
+static int kernel_tracer_fd = -1;
 static int kernel_poll_pipe[2];
 
 /*
@@ -419,7 +419,9 @@ static void cleanup(void)
 
        if (is_root && !opt_no_kernel) {
                DBG2("Closing kernel fd");
-               close(kernel_tracer_fd);
+               if (kernel_tracer_fd >= 0) {
+                       close(kernel_tracer_fd);
+               }
                DBG("Unloading kernel modules");
                modprobe_remove_lttng_all();
        }
@@ -1281,7 +1283,7 @@ error:
  */
 static void *thread_registration_apps(void *data)
 {
-       int sock = 0, i, ret, pollfd;
+       int sock = -1, i, ret, pollfd;
        uint32_t revents, nb_fd;
        struct lttng_poll_event events;
        /*
@@ -1415,8 +1417,12 @@ error:
        /* Notify that the registration thread is gone */
        notify_ust_apps(0);
 
-       close(apps_sock);
-       close(sock);
+       if (apps_sock >= 0) {
+               close(apps_sock);
+       }
+       if (clock >= 0) {
+               close(sock);
+       }
        unlink(apps_unix_sock_path);
 
        lttng_poll_clean(&events);
@@ -1772,7 +1778,7 @@ error_open:
 
 error:
        WARN("No kernel tracer available");
-       kernel_tracer_fd = 0;
+       kernel_tracer_fd = -1;
        return LTTCOMM_KERN_NA;
 }
 
@@ -3249,7 +3255,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx)
                }
 
                /* Kernel tracer check */
-               if (kernel_tracer_fd == 0) {
+               if (kernel_tracer_fd == -1) {
                        /* Basically, load kernel tracer modules */
                        ret = init_kernel_tracer();
                        if (ret != 0) {
@@ -3589,7 +3595,7 @@ init_setup_error:
  */
 static void *thread_manage_clients(void *data)
 {
-       int sock = 0, ret, i, pollfd;
+       int sock = -1, ret, i, pollfd;
        uint32_t revents, nb_fd;
        struct command_ctx *cmd_ctx = NULL;
        struct lttng_poll_event events;
@@ -3747,8 +3753,12 @@ static void *thread_manage_clients(void *data)
 error:
        DBG("Client thread dying");
        unlink(client_unix_sock_path);
-       close(client_sock);
-       close(sock);
+       if (sock >= 0) {
+               close(client_sock);
+       }
+       if (sock >= 0) {
+               close(sock);
+       }
 
        lttng_poll_clean(&events);
        clean_command_ctx(&cmd_ctx);