mdadm: Unify forks behaviour

[thirdparty/mdadm.git] / util.c

diff --git a/util.c b/util.c
index 579dd4238a759a092fa58c2928e4bcaf25c6f115..5879694758ad836afd722f298ce1fc73076fa4aa 100644 (file)
--- a/util.c
+++ b/util.c
@@ -1915,7 +1915,7 @@ int mdmon_running(char *devnm)
 
 int start_mdmon(char *devnm)
 {
-       int i, skipped;
+       int i;
        int len;
        pid_t pid;
        int status;
@@ -1929,7 +1929,10 @@ int start_mdmon(char *devnm)
 
        if (check_env("MDADM_NO_MDMON"))
                return 0;
+       if (continue_via_systemd(devnm, MDMON_SERVICE))
+               return 0;
 
+       /* That failed, try running mdmon directly */
        len = readlink("/proc/self/exe", pathbuf, sizeof(pathbuf)-1);
        if (len > 0) {
                char *sl;
@@ -1943,51 +1946,9 @@ int start_mdmon(char *devnm)
        } else
                pathbuf[0] = '\0';
 
-       /* First try to run systemctl */
-       if (!check_env("MDADM_NO_SYSTEMCTL"))
-               switch(fork()) {
-               case 0:
-                       /* FIXME yuk. CLOSE_EXEC?? */
-                       skipped = 0;
-                       for (i = 3; skipped < 20; i++)
-                               if (close(i) < 0)
-                                       skipped++;
-                               else
-                                       skipped = 0;
-
-                       /* Don't want to see error messages from
-                        * systemctl.  If the service doesn't exist,
-                        * we start mdmon ourselves.
-                        */
-                       close(2);
-                       open("/dev/null", O_WRONLY);
-                       snprintf(pathbuf, sizeof(pathbuf), "mdmon@%s.service",
-                                devnm);
-                       status = execl("/usr/bin/systemctl", "systemctl",
-                                      "start",
-                                      pathbuf, NULL);
-                       status = execl("/bin/systemctl", "systemctl", "start",
-                                      pathbuf, NULL);
-                       exit(1);
-               case -1: pr_err("cannot run mdmon. Array remains readonly\n");
-                       return -1;
-               default: /* parent - good */
-                       pid = wait(&status);
-                       if (pid >= 0 && status == 0)
-                               return 0;
-               }
-
-       /* That failed, try running mdmon directly */
        switch(fork()) {
        case 0:
-               /* FIXME yuk. CLOSE_EXEC?? */
-               skipped = 0;
-               for (i = 3; skipped < 20; i++)
-                       if (close(i) < 0)
-                               skipped++;
-                       else
-                               skipped = 0;
-
+               manage_fork_fds(1);
                for (i = 0; paths[i]; i++)
                        if (paths[i][0]) {
                                execl(paths[i], paths[i],
@@ -2192,6 +2153,81 @@ void enable_fds(int devices)
        setrlimit(RLIMIT_NOFILE, &lim);
 }
 
+/* Close all opened descriptors if needed and redirect
+ * streams to /dev/null.
+ * For debug purposed, leave STDOUT and STDERR untouched
+ * Returns:
+ *     1- if any error occurred
+ *     0- otherwise
+ */
+void manage_fork_fds(int close_all)
+{
+       DIR *dir;
+       struct dirent *dirent;
+
+       close(0);
+       open("/dev/null", O_RDWR);
+
+#ifndef DEBUG
+       dup2(0, 1);
+       dup2(0, 2);
+#endif
+
+       if (close_all == 0)
+               return;
+
+       dir = opendir("/proc/self/fd");
+       if (!dir) {
+               pr_err("Cannot open /proc/self/fd directory.\n");
+               return;
+       }
+       for (dirent = readdir(dir); dirent; dirent = readdir(dir)) {
+               int fd = -1;
+
+               if ((strcmp(dirent->d_name, ".") == 0) ||
+                   (strcmp(dirent->d_name, "..")) == 0)
+                       continue;
+
+               fd = strtol(dirent->d_name, NULL, 10);
+               if (fd > 2)
+                       close(fd);
+       }
+}
+
+/* In a systemd/udev world, it is best to get systemd to
+ * run daemon rather than running in the background.
+ * Returns:
+ *     1- if systemd service has been started
+ *     0- otherwise
+ */
+int continue_via_systemd(char *devnm, char *service_name)
+{
+       int pid, status;
+       char pathbuf[1024];
+
+       /* Simply return that service cannot be started */
+       if (check_env("MDADM_NO_SYSTEMCTL"))
+               return 0;
+       switch (fork()) {
+       case  0:
+               manage_fork_fds(1);
+               snprintf(pathbuf, sizeof(pathbuf),
+                        "%s@%s.service", service_name, devnm);
+               status = execl("/usr/bin/systemctl", "systemctl", "restart",
+                              pathbuf, NULL);
+               status = execl("/bin/systemctl", "systemctl", "restart",
+                              pathbuf, NULL);
+               exit(1);
+       case -1: /* Just do it ourselves. */
+               break;
+       default: /* parent - good */
+               pid = wait(&status);
+               if (pid >= 0 && status == 0)
+                       return 1;
+       }
+       return 0;
+}
+
 int in_initrd(void)
 {
        /* This is based on similar function in systemd. */