blockdev: add --help option

The option is also accepted in format `-h'. As a side effect
usage function is now able to return success, and since it had to
be touched the printing is cleaned up.

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

1 files changed, 23 insertions, 24 deletions

diff --git a/disk-utils/blockdev.c b/disk-utils/blockdev.c
index d1fd24ac0..19a7aa720 100644
--- a/disk-utils/blockdev.c
+++ b/disk-utils/blockdev.c
@@ -175,30 +175,27 @@ static const struct bdc bdcms[] =
 	}
 };
 
-static void
-usage(void) {
+static void __attribute__ ((__noreturn__)) usage(FILE * out)
+{
 	int i;
-	fputc('\n', stderr);
-	fprintf(stderr, _("Usage:\n"));
-	fprintf(stderr, _("  %s -V\n"), program_invocation_short_name);
-	fprintf(stderr, _("  %s --report [devices]\n"), program_invocation_short_name);
-	fprintf(stderr, _("  %s [-v|-q] commands devices\n"), program_invocation_short_name);
-	fputc('\n', stderr);
-
-	fprintf(stderr, _("Available commands:\n"));
-	fprintf(stderr, "  %-25s %s\n", "--getsz",
-			_("get size in 512-byte sectors"));
+	fprintf(out, _("\nUsage:\n"
+		       "  %1$s -V\n"
+		       "  %1$s --report [devices]\n"
+		       "  %1$s [-v|-q] commands devices\n\n"
+		       "Available commands:\n"), program_invocation_short_name);
+
+	fprintf(out, _("  %-25s get size in 512-byte sectors\n"), "--getsz");
 	for (i = 0; i < ARRAY_SIZE(bdcms); i++) {
 		if (bdcms[i].argname)
-			fprintf(stderr, "  %s %-*s %s\n", bdcms[i].name,
-					(int) (24 - strlen(bdcms[i].name)),
-					bdcms[i].argname, _(bdcms[i].help));
+			fprintf(out, "  %s %-*s %s\n", bdcms[i].name,
+				(int)(24 - strlen(bdcms[i].name)),
+				bdcms[i].argname, _(bdcms[i].help));
 		else
-			fprintf(stderr, "  %-25s %s\n", bdcms[i].name,
-					_(bdcms[i].help));
+			fprintf(out, "  %-25s %s\n", bdcms[i].name,
+				_(bdcms[i].help));
 	}
-	fputc('\n', stderr);
-	exit(1);
+	fputc('\n', out);
+	exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
 }
 
 static int
@@ -229,13 +226,15 @@ main(int argc, char **argv) {
 	textdomain(PACKAGE);
 
 	if (argc < 2)
-		usage();
+		usage(stderr);
 
 	/* -V not together with commands */
 	if (!strcmp(argv[1], "-V") || !strcmp(argv[1], "--version")) {
 		printf(_("%s (%s)\n"), program_invocation_short_name, PACKAGE_STRING);
 		exit(0);
 	}
+	if (!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help"))
+		usage(stdout);
 
 	/* --report not together with other commands */
 	if (!strcmp(argv[1], "--report")) {
@@ -269,7 +268,7 @@ main(int argc, char **argv) {
 	}
 
 	if (d >= argc)
-		usage();
+		usage(stderr);
 
 	for (k = d; k < argc; k++) {
 		fd = open(argv[k], O_RDONLY, 0);
@@ -299,7 +298,7 @@ do_commands(int fd, char **argv, int d) {
 		if (!strcmp(argv[i], "-v")) {
 			verbose = 1;
 			continue;
-		}
+                }
 		if (!strcmp(argv[i], "-q")) {
 			verbose = 0;
 			continue;
@@ -317,7 +316,7 @@ do_commands(int fd, char **argv, int d) {
 		j = find_cmd(argv[i]);
 		if (j == -1) {
 			warnx(_("Unknown command: %s"), argv[i]);
-			usage();
+			usage(stderr);
 		}
 
 		switch(bdcms[j].argtype) {
@@ -334,7 +333,7 @@ do_commands(int fd, char **argv, int d) {
 				if (i == d-1) {
 					warnx(_("%s requires an argument"),
 						bdcms[j].name);
-					usage();
+					usage(stderr);
 				}
 				iarg = atoi(argv[++i]);
 			} else