[PATCH] nologin: Prevent error from su -c

* [PATCH] nologin: Prevent error from su -c
@ 2019-10-09 23:08 Stanislav Brabec
  2019-10-11  8:11 ` Karel Zak
  0 siblings, 1 reply; 2+ messages in thread
From: Stanislav Brabec @ 2019-10-09 23:08 UTC (permalink / raw)
  To: util-linux

"su -c" can pass "-c" to nologin. It causes ugly error:

su -c "echo OK" - man
-nologin: invalid option -- 'c'
Try '-nologin --help' for more information.

Accept -c to prevent this error.

Signed-off-by: Josef Cejka <jcejka@suse.com>
Signed-off-by: Stanislav Brabec <sbrabec@suse.cz>
---
 login-utils/nologin.8 | 11 +++++++++--
 login-utils/nologin.c |  9 +++++++--
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/login-utils/nologin.8 b/login-utils/nologin.8
index ee5948443..9389a86c6 100644
--- a/login-utils/nologin.8
+++ b/login-utils/nologin.8
@@ -18,9 +18,16 @@ The exit code returned by
 is always 1.
 .PP
 .SH OPTIONS
-.IP "\fB\-h, \-\-help\fP"
+
+
+.TP
+.IP "\fB\-c\fR, \fB\-\-command\fR \fIcommand\fR"
+Ignored. For compatibility with
+.I su -c "command" - user
+that would cause error otherwise.
+.IP "\fB\-h\fR, \fB\-\-help\fR"
 Display help text and exit.
-.IP "\fB-V, \-\-version"
+.IP "\fB-V\fR, \fB\-\-version\fR"
 Display version information and exit.
 .SH NOTES
 .B nologin
diff --git a/login-utils/nologin.c b/login-utils/nologin.c
index 14a091715..2fc1cd3cf 100644
--- a/login-utils/nologin.c
+++ b/login-utils/nologin.c
@@ -30,7 +30,8 @@ static void __attribute__((__noreturn__)) usage(void)
 	fputs(_("Politely refuse a login.\n"), out);
 
 	fputs(USAGE_OPTIONS, out);
-	printf(USAGE_HELP_OPTIONS(16));
+	fputs(_(" -c, --command <command>  does nothing (for compatibility with su -c)\n"), out);
+	printf(USAGE_HELP_OPTIONS(26));
 
 	printf(USAGE_MAN_TAIL("nologin(8)"));
 	exit(EXIT_FAILURE);
@@ -41,6 +42,7 @@ int main(int argc, char *argv[])
 	int c, fd = -1;
 	struct stat st;
 	static const struct option longopts[] = {
+		{ "command", required_argument, NULL, 'c' },
 		{ "help",    0, NULL, 'h' },
 		{ "version", 0, NULL, 'V' },
 		{ NULL, 0, NULL, 0 }
@@ -50,8 +52,11 @@ int main(int argc, char *argv[])
 	bindtextdomain(PACKAGE, LOCALEDIR);
 	textdomain(PACKAGE);
 
-	while ((c = getopt_long(argc, argv, "hV", longopts, NULL)) != -1) {
+	while ((c = getopt_long(argc, argv, "c:hV", longopts, NULL)) != -1) {
 		switch (c) {
+		case 'c':
+			/* Ignore the command, just don't print unknown option error. */
+			break;
 		case 'h':
 			usage();
 		case 'V':
-- 
2.23.0

-- 
Best Regards / S pozdravem,

Stanislav Brabec
software developer
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