loadavg: restart thread on library reload

[mirror_lxcfs.git] / lxcfs.c

diff --git a/lxcfs.c b/lxcfs.c
index fe381480ca3059097becf15415006cb4894f51fa..76b3ea26f9ca2166f61e5c4de849b007b0240ca7 100644 (file)
--- a/lxcfs.c
+++ b/lxcfs.c
@@ -69,6 +69,46 @@ static void users_unlock(void)
        unlock_mutex(&user_count_mutex);
 }
 
+static pthread_t loadavg_pid = 0;
+
+/* Returns zero on success */
+static int start_loadavg(void) {
+       char *error;
+       pthread_t (*load_daemon)(int);
+
+       dlerror();    /* Clear any existing error */
+
+       load_daemon = (pthread_t (*)(int)) dlsym(dlopen_handle, "load_daemon");
+       error = dlerror();
+       if (error != NULL) {
+               lxcfs_error("load_daemon fails:%s\n", error);
+               return -1;
+       }
+       loadavg_pid = load_daemon(1);
+       if (loadavg_pid == 0)
+               return -1;
+
+       return 0;
+}
+
+/* Returns zero on success */
+static int stop_loadavg(void) {
+       char *error;
+       int (*stop_load_daemon)(pthread_t);
+
+       stop_load_daemon = (int (*)(pthread_t)) dlsym(dlopen_handle, "stop_load_daemon");
+       error = dlerror();
+       if (error != NULL) {
+               lxcfs_error("stop_load_daemon error: %s\n", error);
+               return -1;
+       }
+
+       if (stop_load_daemon(loadavg_pid) != 0)
+               return -1;
+
+       return 0;
+}
+
 static volatile sig_atomic_t need_reload;
 
 /* do_reload - reload the dynamic library.  Done under
@@ -76,6 +116,10 @@ static volatile sig_atomic_t need_reload;
 static void do_reload(void)
 {
        char lxcfs_lib_path[PATH_MAX];
+
+       if (loadavg_pid > 0)
+               stop_loadavg();
+
        if (dlopen_handle) {
                lxcfs_debug("%s\n", "Closing liblxcfs.so handle.");
                dlclose(dlopen_handle);
@@ -101,6 +145,9 @@ static void do_reload(void)
        }
 
 good:
+       if (loadavg_pid > 0)
+               start_loadavg();
+
        if (need_reload)
                lxcfs_error("%s\n", "lxcfs: reloaded");
        need_reload = 0;
@@ -849,12 +896,7 @@ int main(int argc, char *argv[])
        char *pidfile = NULL, *saveptr = NULL, *token = NULL, *v = NULL;
        size_t pidfile_len;
        bool debug = false, nonempty = false;
-       pthread_t pid;
-       int s = 0;
-       char *error;
        bool load_use = false;
-       pthread_t (*load_daemon)(int);
-       void (*load_free)(void);
        /*
         * what we pass to fuse_main is:
         * argv[0] -s [-f|-d] -o allow_other,directio argv[1] NULL
@@ -922,42 +964,13 @@ int main(int argc, char *argv[])
        if ((pidfd = set_pidfile(pidfile)) < 0)
                goto out;
 
-       if (load_use == true) {
-               dlerror();    /* Clear any existing error */
+       if (load_use && start_loadavg() != 0)
+               goto out;
 
-               load_daemon = (pthread_t (*)(int)) dlsym(dlopen_handle, "load_daemon");
-               error = dlerror();
-               if (error != NULL) {
-                       lxcfs_error("load_daemon fails:%s\n", error);
-                       goto out;
-               }
-               pid = load_daemon(1);
-               if (pid == 0)
-                       goto out;
-       }
        if (!fuse_main(nargs, newargv, &lxcfs_ops, NULL))
                ret = EXIT_SUCCESS;
-       if (load_use == true) {
-               s = pthread_cancel(pid);
-               if (s == 0) {
-                       s = pthread_join(pid, NULL); /* Make sure sub thread has been canceled. */
-                       if (s != 0) {
-                               lxcfs_error("%s\n", "load_free error!");
-                               goto out;
-                       }
-                       dlerror();    /* Clear any existing error */
-
-                       load_free = (void (*)(void)) dlsym(dlopen_handle, "load_free");
-                       error = dlerror();
-                       if (error != NULL) {
-                               lxcfs_error("load_free error: %s\n", error);
-                               goto out;
-                       }
-                       load_free();
-               } else {
-                       lxcfs_error("%s\n", "load_free error!");
-               }
-       }
+       if (load_use)
+               stop_loadavg();
 
 out:
        if (dlopen_handle)