switch_root: clean up argv[] usage, add -h and -V

Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/sys-utils/switch_root.c b/sys-utils/switch_root.c
index 5dcc7f1e4b669ec6741402500683c1fa242be270..14d2916bfa1cf25c3ce9970a9baa8c508169ec0e 100644 (file)
--- a/sys-utils/switch_root.c
+++ b/sys-utils/switch_root.c
@@ -38,12 +38,6 @@
 #define MS_MOVE 8192
 #endif
 
-enum {
-       ok,
-       err_no_directory,
-       err_usage,
-};
-
 /* remove all files/directories below dirName -- don't cross mountpoints */
 static int recursiveRemove(char *dirName)
 {
@@ -115,7 +109,6 @@ static int switchroot(const char *newroot)
 {
        /*  Don't try to unmount the old "/", there's no way to do it. */
        const char *umounts[] = { "/dev", "/proc", "/sys", NULL };
-       int errnum;
        int i;
 
        for (i = 0; umounts[i] != NULL; i++) {
@@ -153,34 +146,48 @@ static void usage(FILE *output)
 {
        fprintf(output, "usage: %s <newrootdir> <init> <args to init>\n",
                        program_invocation_short_name);
-       if (output == stderr)
-               exit(EXIT_FAILURE);
+       exit(output == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
+}
+
+static void version(void)
+{
+       fprintf(stdout,  "%s from %s\n", program_invocation_short_name,
+                       PACKAGE_STRING);
        exit(EXIT_SUCCESS);
 }
 
 int main(int argc, char *argv[])
 {
-       char *newroot = argv[1];
-       char *init = argv[2];
-       char **initargs = &argv[2];
+       char *newroot, *init, **initargs;
 
-       if (newroot == NULL || newroot[0] == '\0' ||
-           init == NULL || init[0] == '\0' ) {
+       if (argv[1] && (!strcmp(argv[1], "--help") || !strcmp(argv[1], "-h")))
+               usage(stdout);
+       if (argv[1] && (!strcmp(argv[1], "--version") || !strcmp(argv[1], "-V")))
+               version();
+       if (argc < 3)
+               usage(stderr);
+
+       newroot = argv[1];
+       init = argv[2];
+       initargs = &argv[2];
+
+       if (!*newroot || !*init)
                usage(stderr);
-       }
 
        if (switchroot(newroot))
                errx(EXIT_FAILURE, "failed. Sorry.");
 
-       if (access(initargs[0], X_OK))
-               warn("cannot access %s", initargs[0]);
+       if (access(init, X_OK))
+               warn("cannot access %s", init);
 
        /* get session leader */
        setsid();
+
        /* set controlling terminal */
-       ioctl (0, TIOCSCTTY, 1);
+       if (ioctl (0, TIOCSCTTY, 1))
+               warn("failed to TIOCSCTTY");
 
-       execv(initargs[0], initargs);
-       err(EXIT_FAILURE, "failed to execute %s", initargs[0]);
+       execv(init, initargs);
+       err(EXIT_FAILURE, "failed to execute %s", init);
 }