switch_root: align with howto-usage-function.txt

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

diff --git a/sys-utils/switch_root.c b/sys-utils/switch_root.c
index f86b8c697a887de3d88ef6d25daf2984a48a7b9c..7c56396820b81fb5e72cda4b04f6999f09ab1db5 100644 (file)
--- a/sys-utils/switch_root.c
+++ b/sys-utils/switch_root.c
@@ -32,7 +32,9 @@
 #include <errno.h>
 #include <ctype.h>
 #include <dirent.h>
+
 #include "c.h"
+#include "nls.h"
 
 #ifndef MS_MOVE
 #define MS_MOVE 8192
@@ -170,18 +172,17 @@ static int switchroot(const char *newroot)
        return 0;
 }
 
-static void usage(FILE *output)
+static void __attribute__((__noreturn__)) usage(FILE *output)
 {
-       fprintf(output, "usage: %s <newrootdir> <init> <args to init>\n",
-                       program_invocation_short_name);
-       exit(output == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
-}
+       fputs(USAGE_HEADER, output);
+       fprintf(output, " %s [options] <newrootdir> <init> <args to init>\n",
+               program_invocation_short_name);
+       fputs(USAGE_OPTIONS, output);
+       fputs(USAGE_HELP, output);
+       fputs(USAGE_VERSION, output);
+       fprintf(output, USAGE_MAN_TAIL("switch_root(8)"));
 
-static void version(void)
-{
-       fprintf(stdout,  "%s from %s\n", program_invocation_short_name,
-                       PACKAGE_STRING);
-       exit(EXIT_SUCCESS);
+       exit(output == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
 }
 
 int main(int argc, char *argv[])
@@ -190,8 +191,10 @@ int main(int argc, char *argv[])
 
        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 (argv[1] && (!strcmp(argv[1], "--version") || !strcmp(argv[1], "-V"))) {
+               printf(UTIL_LINUX_VERSION);
+               return EXIT_SUCCESS;
+       }
        if (argc < 3)
                usage(stderr);