Make use of getopt_long

Simplify main.c code by using getopt_long method.

Reviewed-by: Cyril Hrubis <chrubis@suse.cz>

Author: acerv

main.c

@@ -9,48 +9,60 @@
 #include <errno.h>
 #include <string.h>
 #include <unistd.h>
+#include <getopt.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include "ltx.h"
 
 int main(int argc, char *argv[])
 {
+	int opt;
+	int option_index = 0;
+	char *serial_port = NULL;
 	int stdin_fd = STDIN_FILENO;
-	int stdout_fd = STDOUT_FILENO;;
+	int stdout_fd = STDOUT_FILENO;
 
-	if (argc >= 2 && strcmp(argv[1], "-i") && strcmp(argv[1], "--interactive")) {
-		if (!strcmp(argv[1], "-s") || !strcmp(argv[1], "--serial")) {
-			if (argc != 3) {
-				printf("Serial port is not defined\n");
-				return 1;
-			}
+	static struct option long_options[] = {
+		{"serial", required_argument, NULL, 's'},
+		{"version", no_argument, NULL, 'v'},
+		{"help", no_argument, NULL, 'h'},
+		{0, 0, 0, 0}
+	};
 
-			const char *port = argv[2];
-
-			if (access(port, F_OK) != 0) {
-				printf("%s doesn't exist\n", port);
-				return 1;
-			}
-
-			stdin_fd = stdout_fd = open(port, O_RDWR | O_NOCTTY);
-			if (stdin_fd == -1) {
-				printf("Can't open %s (%s)\n", port, strerror(errno));
-				return 1;
-			}
-		} else if (!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help")) {
+	while ((opt = getopt_long(
+			argc,
+			argv,
+			"s:vh",
+			long_options,
+			&option_index)) != -1) {
+		switch(opt) {
+		case 's':
+			serial_port = optarg;
+			break;
+		case 'v':
+			printf("%s\n", VERSION);
+			return 0;
+		case 'h':
+		default:
 			printf(
-				"Usage: ./ltx [-h|-i|-s]\n\n"
-				"  -i | --interactive  communicate via stdin|stdout (default)\n"
+				"Usage: ./ltx [-s|-v|-h]\n\n"
 				"  -s | --serial       communicate via serial port\n"
-				"  -h | --help         print help message\n"
-				"  -v | --version      print version\n\n"
+				"  -v | --version      print version\n"
+				"  -h | --help         print help message\n\n"
 			);
 			return 0;
-		} else if (!strcmp(argv[1], "-v") || !strcmp(argv[1], "--version")) {
-			printf("%s\n", VERSION);
-			return 0;
-		} else {
-			printf("Unknown parameter: %s\n", argv[1]);
+		}
+	}
+
+	if (serial_port) {
+		if (access(serial_port, F_OK) != 0) {
+			printf("%s doesn't exist\n", serial_port);
+			return 1;
+		}
+
+		stdin_fd = stdout_fd = open(serial_port, O_RDWR | O_NOCTTY);
+		if (stdin_fd == -1) {
+			printf("Can't open %s (%s)\n", serial_port, strerror(errno));
 			return 1;
 		}
 	}