ipaddr

commit b724ef9c7360cbe63727ac4b90bd52500af1393d
parent 013cb6ba880648933e4bf42c8aebb088e532fb65
Author: Stephen Gregoratto <dev@sgregoratto.me>
Date:   Thu, 31 Oct 2019 21:10:21 +1100

improve option handling, memory usage and semantics.

- Refactor the option handling to add a help flag and keep it to 2
  levels of indentation.
- Don't duplicate the interface string.
- Rename ifa to iter, since we use it to iterate over the interfaces.

Diffstat:
M
ipaddr.c
 | 
52
+++++++++++++++++++++++++---------------------------

1 file changed, 25 insertions(+), 27 deletions(-)
diff --git a/ipaddr.c b/ipaddr.c
@@ -18,11 +18,10 @@
 int
 main(int argc, char **argv)
 {
-	struct ifaddrs *ifaddr, *ifa;
-	int status;
-	char host[NI_MAXHOST];
-	char *iface;
+	struct ifaddrs *ifaddr, *iter;
 	size_t sa_size;
+	int status;
+	char host[NI_MAXHOST + 1], *iface;
 
 #if HAVE_PLEDGE
 	if (pledge("stdio") == -1)
@@ -35,47 +34,46 @@ main(int argc, char **argv)
 		goto usage;
 	}
 
-	if (argv[1][0] == '-') {
-		switch (argv[1][1]) {
-		case '4':
-			sa_size = sizeof(struct sockaddr_in);
-			break;
-		case '6':
-			sa_size = sizeof(struct sockaddr_in6);
-			break;
-		default:
-			warnx("invalid IP version");
-			goto usage;
-		}
-	} else {
-		warnx("invalid IP version");
+	if (argv[1][0] != '-') {
+		warnx("invalid argument");
+		goto usage;
+	}
+
+	switch (argv[1][1]) {
+	case '4':
+		sa_size = sizeof(struct sockaddr_in);
+		break;
+	case '6':
+		sa_size = sizeof(struct sockaddr_in6);
+		break;
+	default:
+		warnx("invalid argument");
+	case 'h':
 		goto usage;
 	}
 
-	if ((iface = strdup(argv[2])) == NULL)
-		err(1, "strdup");
+	iface = argv[2];
 
 	if (getifaddrs(&ifaddr) == -1)
 		err(1, "getifaddrs");
 
-	for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
-		if (ifa->ifa_addr == NULL)
+	for (iter = ifaddr; iter != NULL; iter = iter->ifa_next) {
+		if (iter->ifa_addr == NULL)
 			continue;
 
-		status = getnameinfo(ifa->ifa_addr, sa_size, host, NI_MAXHOST,
+		status = getnameinfo(iter->ifa_addr, sa_size, host, NI_MAXHOST,
 				     NULL, 0, NI_NUMERICHOST);
 
-		if ((strncmp(ifa->ifa_name, iface, strlen(iface)) == 0)
-		    && (ifa->ifa_addr->sa_family == AF_INET)) {
+		if ((strncmp(iter->ifa_name, iface, strlen(iface)) == 0)
+		    && (iter->ifa_addr->sa_family == AF_INET)) {
 			if (status != 0)
 				errx(1, "getnameinfo: %s",
 				     gai_strerror(status));
-			printf("%s %s\n", ifa->ifa_name, host);
+			printf("%s %s\n", iter->ifa_name, host);
 			break;
 		}
 	}
 
-	free(iface);
 	freeifaddrs(ifaddr);
 
 	return 0;