[PATCH v3 6/6] sign-file: improve help message

[Shreenidhi Shedi]

Add a proper help message with examples on how to use this tool.

Signed-off-by: Shreenidhi Shedi <sshedi@xxxxxxxxxx>
---
 scripts/sign-file.c | 49 ++++++++++++++++++++++++++++++++++++---------
 1 file changed, 40 insertions(+), 9 deletions(-)

diff --git a/scripts/sign-file.c b/scripts/sign-file.c
index 0729d8df5660..d9499ea5c8cc 100644
--- a/scripts/sign-file.c
+++ b/scripts/sign-file.c
@@ -74,13 +74,44 @@ struct module_signature {
 static const char magic_number[] = "~Module signature appended~\n";
 
 static __attribute__((noreturn))
-void format(void)
+void print_usage(int retval)
 {
-	fprintf(stderr,
-		"Usage: scripts/sign-file [-dp] <hash algo> <key> <x509> <module> [<dest>]\n");
-	fprintf(stderr,
-		"       scripts/sign-file -s <raw sig> <hash algo> <x509> <module> [<dest>]\n");
-	exit(2);
+	fprintf(stderr, "Usage: scripts/sign-file [OPTIONS]... [MODULE]...\n");
+	fprintf(stderr, "Available options:\n");
+	fprintf(stderr, "-h, --help		Print this help message and exit\n");
+
+	fprintf(stderr, "\nOptional args:\n");
+	fprintf(stderr, "-s, --savesig		Save signature\n");
+	fprintf(stderr, "-o, --signonly		Sign only\n");
+	fprintf(stderr, "-b, --bulksign		Sign modules in bulk\n");
+	fprintf(stderr, "-l, --replaceorig	Replace original\n");
+#ifndef USE_PKCS7
+	fprintf(stderr, "-k, --usekeyid		Use key ID\n");
+#endif
+	fprintf(stderr, "-r, --rawsig <sig>	Raw signature\n");
+	fprintf(stderr, "-d, --dest <dest>	Destination path ");
+	fprintf(stderr, "(Exclusive with bulk option)\n");
+
+	fprintf(stderr, "\nMandatory args:\n");
+	fprintf(stderr, "-p, --privkey <key>	Private key\n");
+	fprintf(stderr, "-a, --hashalgo <alg>	Hash algorithm\n");
+	fprintf(stderr, "-x, --x509 <x509>	X509\n");
+
+	fprintf(stderr, "\nExamples:\n");
+
+	fprintf(stderr, "\nRegular signing:\n");
+	fprintf(stderr, "scripts/sign-file -a sha512 -p certs/signing_key.pem ");
+	fprintf(stderr, "-x certs/signing_key.x509 <module>\n");
+
+	fprintf(stderr, "\nSigning with destination path:\n");
+	fprintf(stderr, "scripts/sign-file -a sha512 -p certs/signing_key.pem ");
+	fprintf(stderr, "-x certs/signing_key.x509 <module> -d <path>\n");
+
+	fprintf(stderr, "\nSigning modules in bulk:\n");
+	fprintf(stderr, "scripts/sign-file -a sha512 -p certs/signing_key.pem ");
+	fprintf(stderr, "-x certs/signing_key.x509 -b <module1> <module2> ...\n");
+
+	exit(retval);
 }
 
 static void display_openssl_errors(int l)
@@ -264,7 +295,7 @@ static void parse_args(int argc, char **argv, struct cmd_opts *opts)
 #endif
 		switch (opt) {
 		case 'h':
-			format();
+			print_usage(0);
 			break;
 
 		case 'r':
@@ -315,7 +346,7 @@ static void parse_args(int argc, char **argv, struct cmd_opts *opts)
 			break;
 
 		default:
-			format();
+			print_usage(2);
 			break;
 		}
 	} while (opt != -1);
@@ -355,7 +386,7 @@ int sign_file(int argc, char **argv, struct cmd_opts *opts)
 #endif
 
 	if ((bulk_sign && dest_name) || (!bulk_sign && argc != 1))
-		format();
+		print_usage(2);
 
 	if (dest_name && strcmp(argv[0], dest_name)) {
 		replace_orig = false;
-- 
2.39.1