upgraded: improve error handling

* exit with code 1 instead of unusual -1 in the parent process
* exit using _exit() when child exec fails
* fix fork/exec error messages
* only uloop_run() after successful child fork (uloop_end() before
  uloop_run() doesn't have any effect, so uloop_run() would hang forever)
* minor code cleanup

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>

diff --git a/upgraded/upgraded.c b/upgraded/upgraded.c
index 6bc5ad8f94f3060c7c56535418b5df6f64df2f26..09c623cf804b43c826190300a40e2c4bf9aabfa3 100644 (file)
--- a/upgraded/upgraded.c
+++ b/upgraded/upgraded.c
@@ -43,23 +43,24 @@ static void upgrade_proc_cb(struct uloop_process *proc, int ret)
 
 static void sysupgrade(char *path, char *command)
 {
-       char *args[] = { "/lib/upgrade/stage2", NULL, NULL, NULL };
+       char *args[] = { "/lib/upgrade/stage2", path, command, NULL };
 
-       args[1] = path;
-       args[2] = command;
        upgrade_proc.cb = upgrade_proc_cb;
        upgrade_proc.pid = fork();
-       if (!upgrade_proc.pid) {
-               execvp(args[0], args);
+       if (upgrade_proc.pid < 0) {
                fprintf(stderr, "Failed to fork sysupgrade\n");
-               exit(-1);
+               return;
        }
-       if (upgrade_proc.pid <= 0) {
-               fprintf(stderr, "Failed to start sysupgrade\n");
-               uloop_end();
+
+       if (!upgrade_proc.pid) {
+               /* Child */
+               execvp(args[0], args);
+               fprintf(stderr, "Failed to exec sysupgrade\n");
+               _exit(-1);
        }
 
        uloop_process_add(&upgrade_proc);
+       uloop_run();
 }
 
 int main(int argc, char **argv)
@@ -68,32 +69,31 @@ int main(int argc, char **argv)
 
        if (p != 1) {
                fprintf(stderr, "this tool needs to run as pid 1\n");
-               return -1;
+               return 1;
        }
 
        int fd = open("/", O_DIRECTORY|O_PATH);
        if (fd < 0) {
                fprintf(stderr, "unable to open prefix directory: %s\n", strerror(errno));
-               return -1;
+               return 1;
        }
 
        chroot(".");
 
        if (fchdir(fd) == -1) {
                fprintf(stderr, "failed to chdir to prefix directory: %s\n", strerror(errno));
-               return -1;
+               return 1;
        }
        close(fd);
 
        if (argc != 3) {
                fprintf(stderr, "sysupgrade stage 2 failed, invalid command line\n");
-               return -1;
+               return 1;
        }
 
        uloop_init();
        watchdog_init(0);
        sysupgrade(argv[1], argv[2]);
-       uloop_run();
 
        reboot(RB_AUTOBOOT);