Fix: handle EINTR for every read()

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

diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
index 91fba2643fc2ae94acf79850fd0e9aa589cfbf90..477a9413b71692d8630572dc8ab6de49b5534bad 100644 (file)
--- a/src/bin/lttng-sessiond/main.c
+++ b/src/bin/lttng-sessiond/main.c
@@ -691,36 +691,40 @@ static void *thread_manage_kernel(void *data)
 
        DBG("[thread] Thread manage kernel started");
 
+       /*
+        * This first step of the while is to clean this structure which could free
+        * non NULL pointers so zero it before the loop.
+        */
+       memset(&events, 0, sizeof(events));
+
        if (testpoint(thread_manage_kernel)) {
                goto error_testpoint;
        }
 
        health_code_update(&health_thread_kernel);
 
-       ret = create_thread_poll_set(&events, 2);
-       if (ret < 0) {
-               goto error_poll_create;
-       }
-
-       ret = lttng_poll_add(&events, kernel_poll_pipe[0], LPOLLIN);
-       if (ret < 0) {
-               goto error;
-       }
-
        if (testpoint(thread_manage_kernel_before_loop)) {
-               goto error;
+               goto error_testpoint;
        }
 
        while (1) {
                health_code_update(&health_thread_kernel);
 
                if (update_poll_flag == 1) {
-                       /*
-                        * Reset number of fd in the poll set. Always 2 since there is the thread
-                        * quit pipe and the kernel pipe.
-                        */
-                       events.nb_fd = 2;
+                       /* Clean events object. We are about to populate it again. */
+                       lttng_poll_clean(&events);
+
+                       ret = create_thread_poll_set(&events, 2);
+                       if (ret < 0) {
+                               goto error_poll_create;
+                       }
 
+                       ret = lttng_poll_add(&events, kernel_poll_pipe[0], LPOLLIN);
+                       if (ret < 0) {
+                               goto error;
+                       }
+
+                       /* This will add the available kernel channel if any. */
                        ret = update_kernel_poll(&events);
                        if (ret < 0) {
                                goto error;
@@ -728,7 +732,7 @@ static void *thread_manage_kernel(void *data)
                        update_poll_flag = 0;
                }
 
-               DBG("Thread kernel polling on %d fds", events.nb_fd);
+               DBG("Thread kernel polling on %d fds", LTTNG_POLL_GETNB(&events));
 
                /* Poll infinite value of time */
        restart:
@@ -768,7 +772,13 @@ static void *thread_manage_kernel(void *data)
 
                        /* Check for data on kernel pipe */
                        if (pollfd == kernel_poll_pipe[0] && (revents & LPOLLIN)) {
-                               ret = read(kernel_poll_pipe[0], &tmp, 1);
+                               do {
+                                       ret = read(kernel_poll_pipe[0], &tmp, 1);
+                               } while (ret < 0 && errno == EINTR);
+                               /*
+                                * Ret value is useless here, if this pipe gets any actions an
+                                * update is required anyway.
+                                */
                                update_poll_flag = 1;
                                continue;
                        } else {
@@ -1122,7 +1132,7 @@ static void *thread_manage_apps(void *data)
        health_code_update(&health_thread_app_manage);
 
        while (1) {
-               DBG("Apps thread polling on %d fds", events.nb_fd);
+               DBG("Apps thread polling on %d fds", LTTNG_POLL_GETNB(&events));
 
                /* Inifinite blocking call, waiting for transmission */
        restart:
@@ -1162,7 +1172,9 @@ static void *thread_manage_apps(void *data)
                                        goto error;
                                } else if (revents & LPOLLIN) {
                                        /* Empty pipe */
-                                       ret = read(apps_cmd_pipe[0], &ust_cmd, sizeof(ust_cmd));
+                                       do {
+                                               ret = read(apps_cmd_pipe[0], &ust_cmd, sizeof(ust_cmd));
+                                       } while (ret < 0 && errno == EINTR);
                                        if (ret < 0 || ret < sizeof(ust_cmd)) {
                                                PERROR("read apps cmd pipe");
                                                goto error;