Add getaddrinfo(1).

utils/.gitignore

@@ -20,6 +20,7 @@ env
 expr
 false
 find
+getaddrinfo
 halt
 head
 help

utils/Makefile

@@ -31,6 +31,7 @@ env \
 expr \
 false \
 find \
+getaddrinfo \
 halt \
 head \
 help \

utils/getaddrinfo.c

@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2016 Jonas 'Sortie' Termansen.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * getaddrinfo.c
+ * Wrapper program for getaddrinfo(3).
+ */
+
+#include <sys/socket.h>
+
+#include <arpa/inet.h>
+#include <err.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static void compact_arguments(int* argc, char*** argv)
+{
+	for ( int i = 0; i < *argc; i++ )
+	{
+		while ( i < *argc && !(*argv)[i] )
+		{
+			for ( int n = i; n < *argc; n++ )
+				(*argv)[n] = (*argv)[n+1];
+			(*argc)--;
+		}
+	}
+}
+
+int main(int argc, char* argv[])
+{
+	const char* argv0 = argv[0];
+	for ( int i = 1; i < argc; i++ )
+	{
+		const char* arg = argv[i];
+		if ( arg[0] != '-' || !arg[1] )
+			continue;
+		argv[i] = NULL;
+		if ( !strcmp(arg, "--") )
+			break;
+		if ( arg[1] != '-' )
+		{
+			char c;
+			while ( (c = *++arg) ) switch ( c )
+			{
+			default:
+				fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
+				exit(1);
+			}
+		}
+		else
+		{
+			fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
+			exit(1);
+		}
+	}
+
+	compact_arguments(&argc, &argv);
+
+	if ( argc < 2 )
+		errx(1, "No host given");
+	const char* host = argv[1];
+	if ( 3 < argc )
+		errx(1, "Unexpected extra operand `%s'", argv[3]);
+	const char* service = argv[2];
+
+	struct addrinfo* res = NULL;
+	int status = getaddrinfo(host, service, NULL, &res);
+	if ( status == EAI_SYSTEM )
+		err(1, "%s", host);
+	if ( status )
+		errx(1, "%s: %s", host, gai_strerror(status));
+	for ( struct addrinfo* iter = res; iter; iter = iter->ai_next )
+	{
+		// TODO: Implement and use getnameinfo(3).
+		if ( iter->ai_family == AF_INET )
+		{
+			struct sockaddr_in* sin = (struct sockaddr_in*) iter->ai_addr;
+			char str[INET_ADDRSTRLEN];
+			inet_ntop(iter->ai_family, &sin->sin_addr, str, sizeof(str));
+			printf("%s\n", str);
+		}
+		else if ( iter->ai_family == AF_INET6 )
+		{
+			struct sockaddr_in6* sin6 = (struct sockaddr_in6*) iter->ai_addr;
+			char str[INET6_ADDRSTRLEN];
+			inet_ntop(iter->ai_family, &sin6->sin6_addr, str, sizeof(str));
+			printf("%s\n", str);
+		}
+		else
+			printf("(unknown address family %i)\n", iter->ai_family);
+	}
+	freeaddrinfo(res);
+
+	return 0;
+}