main: Add help output and check for operand

1 files changed, 78 insertions, 4 deletions

diff --git a/src/main.c b/src/main.c
index 1cc20a4..99a3b9d 100644
--- a/src/main.c
+++ b/src/main.c
@@ -70,6 +70,52 @@ struct option _longopts[] = {
 #endif
 
 static void
+_help(const char *program_name)
+{
+	printf("Usage: %s OPTION... PACKAGE\n", program_name);
+	puts("Options:");
+#ifdef HAVE_GETOPT_LONG
+	puts("  -I, --info=CONTROL-FILE  Print the named control file.  If "
+	                                "this option is");
+	puts("                           given multiple times, the named "
+	                                "control files will be");
+	puts("                           printed in the order they appear in "
+	                                "the package.");
+	puts("  -f, --control            Print the control file.");
+	puts("  -c, --contents           List the contents of the filesystem "
+	                                "tree archive");
+	puts("                           portion of the package.  It is "
+	                                "currently produced in");
+	puts("                           a format similar to that generated by "
+	                                "GNU and BusyBox");
+	puts("                           tar's verbose listing.  User and "
+	                                "group IDs and names");
+	puts("                           are not checked against those on the "
+	                                "host system,");
+	puts("                           since they may differ.");
+	puts("  -h, --help               Show this help information and exit.");
+	puts("  -V, --version            Show version information and exit.");
+#else
+	puts("  -I  Print the named control file.  If this option is given "
+	           "multiple times, the");
+	puts("      named control files will be printed in the order they "
+	           "appear in the");
+	puts("      package.");
+	puts("  -f  Print the control file.");
+	puts("  -c  List the contents of the filesystem tree archive portion "
+	           "of the package.");
+	puts("      It is currently produced in a format similar to that "
+	           "generated by GNU and");
+	puts("      BusyBox tar's verbose listing.  User and group IDs and "
+	           "names are not");
+	puts("      checked against those on the host system, since they may "
+	           "differ.");
+	puts("  -h  Show this help information and exit.");
+	puts("  -V  Show version information and exit.");
+#endif
+}
+
+static void
 _version(void)
 {
 	printf("%s %s%s\n", PACKAGE_NAME, PACKAGE_VERSION, PACKAGE_VERSION_GIT);
@@ -83,14 +129,28 @@ _version(void)
 	printf("Please report bugs to <%s>.\n", PACKAGE_BUGREPORT);
 }
 
+static void
+_help_tip(const char *program_name)
+{
+	fprintf(stderr, "Try \"%s %s\" for more information\n", program_name,
+#ifdef HAVE_GETOPT_LONG
+			"--help"
+#else
+			"-h"
+#endif
+			);
+}
+
 int
 main(int argc, char *argv[])
 {
+	const char                      *program_name;
 	struct opkg_opk_ustar_seek_name *control_files;
 	int                              list_members;
 	int                              opt;
 	struct opkg_opk_opk             *opk;
 
+	program_name  = argv[0];
 	control_files = NULL;
 	list_members  = 0;
 #ifdef HAVE_GETOPT_LONG
@@ -118,19 +178,33 @@ main(int argc, char *argv[])
 				list_members = 1;
 				break;
 			case 'h':
-				/* TODO */
-				break;
+				_help(program_name);
+				return EXIT_SUCCESS;
 			case 'V':
 				_version();
 				return EXIT_SUCCESS;
 			default:
-				/* TODO */
-				break;
+				fprintf(stderr, "%s: Invalid option: \"%c\"\n",
+						program_name, optopt);
+				_help_tip(program_name);
+				return EXIT_FAILURE;
 		}
 	}
 	argc -= optind;
 	argv += optind;
 
+	if (argc < 1) {
+		fprintf(stderr, "%s: Missing package file operand\n",
+				program_name);
+		_help_tip(program_name);
+		return EXIT_FAILURE;
+	} else if (argc > 1) {
+		fprintf(stderr, "%s: Too many package file operands\n",
+				program_name);
+		_help_tip(program_name);
+		return EXIT_FAILURE;
+	}
+
 	/* Initialize outer archive. */
 	opk = opkg_opk_opk_init(argv[0]);
 	if (opk == NULL) {