[PATCH v5 5/7] sign-file: improve help message

[Shreenidhi Shedi <yesshedi@gmail.com>]

From: Shreenidhi Shedi <yesshedi@gmail.com>

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

Signed-off-by: Shreenidhi Shedi <yesshedi@gmail.com>
---
 scripts/sign-file.c | 48 ++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 41 insertions(+), 7 deletions(-)

diff --git a/scripts/sign-file.c b/scripts/sign-file.c
index 0a275256ca16..d3abc5721a7e 100644
--- a/scripts/sign-file.c
+++ b/scripts/sign-file.c
@@ -74,12 +74,43 @@ struct module_signature {
 static char magic_number[] = "~Module signature appended~\n";
 
 static __attribute__((noreturn))
-void format(void)
+void print_usage(void)
 {
-	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");
+	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, --rawsig <sig>     Raw signature\n");
+	fprintf(stderr, "-p, --savesig          Save signature\n");
+	fprintf(stderr, "-d, --signonly         Sign only\n");
+#ifndef USE_PKCS7
+	fprintf(stderr, "-k, --usekeyid         Use key ID\n");
+#endif
+	fprintf(stderr, "-b, --bulksign         Sign modules in bulk\n");
+	fprintf(stderr, "-r, --replaceorig      Replace original\n");
+	fprintf(stderr, "-t, --dest <dest>      Destination path ");
+	fprintf(stderr, "(Exclusive with bulk option)\n");
+
+	fprintf(stderr, "\nMandatory args:\n");
+	fprintf(stderr, "-i, --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, "\n    Regular signing:\n");
+	fprintf(stderr, "     scripts/sign-file -a sha512 -i certs/signing_key.pem ");
+	fprintf(stderr, "-x certs/signing_key.x509 <module>\n");
+
+	fprintf(stderr, "\n    Signing with destination path:\n");
+	fprintf(stderr, "     scripts/sign-file -a sha512 -i certs/signing_key.pem ");
+	fprintf(stderr, "-x certs/signing_key.x509 <module> -t <path>\n");
+
+	fprintf(stderr, "\n    Signing modules in bulk:\n");
+	fprintf(stderr, "     scripts/sign-file -a sha512 -i certs/signing_key.pem ");
+	fprintf(stderr, "-x certs/signing_key.x509 -b <module1> <module2> ...\n");
+
 	exit(2);
 }
 
@@ -281,7 +312,7 @@ static void parse_args(int argc, char **argv, struct cmd_opts *opts)
 #endif
 
 		case 'h':
-			format();
+			print_usage();
 			break;
 
 		case 'i':
@@ -312,7 +343,7 @@ static void parse_args(int argc, char **argv, struct cmd_opts *opts)
 			break;
 
 		default:
-			format();
+			print_usage();
 			break;
 		}
 	} while (opt != -1);
@@ -472,6 +503,9 @@ int main(int argc, char **argv)
 	argc -= optind;
 	argv += optind;
 
+	if ((opts.bulk_sign && opts.dest_name) || (!opts.bulk_sign && argc != 1))
+		print_usage();
+
 	OpenSSL_add_all_algorithms();
 	ERR_load_crypto_strings();
 	ERR_clear_error();
-- 
2.39.2