xatonum.h: add comment

[oweals/busybox.git] / networking / nslookup.c

diff --git a/networking/nslookup.c b/networking/nslookup.c
index 5a08844f051b5c93933443b7ae11257ba30b940c..183ae152de0bcfe8493798adbb4edc6bfd99b24a 100644 (file)
--- a/networking/nslookup.c
+++ b/networking/nslookup.c
@@ -12,7 +12,7 @@
  */
 
 #include <resolv.h>
-#include "busybox.h"
+#include "libbb.h"
 
 /*
  *  I'm only implementing non-interactive mode;
@@ -47,24 +47,11 @@
  * ns3.kernel.org  internet address = 204.152.191.36
  */
 
-static int sockaddr_to_dotted(struct sockaddr *saddr, char *buf, int buflen)
-{
-       if (buflen <= 0) return -1;
-       buf[0] = '\0';
-       if (saddr->sa_family == AF_INET) {
-               inet_ntop(AF_INET, &((struct sockaddr_in*)saddr)->sin_addr, buf, buflen);
-               return 0;
-       }
-       if (saddr->sa_family == AF_INET6) {
-               inet_ntop(AF_INET6, &((struct sockaddr_in6*)saddr)->sin6_addr, buf, buflen);
-               return 0;
-       }
-       return -1;
-}
-
 static int print_host(const char *hostname, const char *header)
 {
-       char str[128];  /* IPv6 address will fit, hostnames hopefully too */
+       /* We can't use xhost2sockaddr() - we want to get ALL addresses,
+        * not just one */
+
        struct addrinfo *result = NULL;
        int rc;
        struct addrinfo hint;
@@ -76,25 +63,57 @@ static int print_host(const char *hostname, const char *header)
        hint.ai_socktype = SOCK_STREAM;
        // hint.ai_flags = AI_CANONNAME;
        rc = getaddrinfo(hostname, NULL /*service*/, &hint, &result);
+
        if (!rc) {
                struct addrinfo *cur = result;
-               // printf("%s\n", cur->ai_canonname); ?
+               unsigned cnt = 0;
+
+               printf("%-10s %s\n", header, hostname);
+               // puts(cur->ai_canonname); ?
                while (cur) {
-                       sockaddr_to_dotted(cur->ai_addr, str, sizeof(str));
-                       printf("%s  %s\nAddress: %s", header, hostname, str);
-                       str[0] = ' ';
-                       if (getnameinfo(cur->ai_addr, cur->ai_addrlen, str+1, sizeof(str)-1, NULL, 0, NI_NAMEREQD))
-                               str[0] = '\0';
-                       puts(str);
+                       char *dotted, *revhost;
+                       dotted = xmalloc_sockaddr2dotted_noport(cur->ai_addr);
+                       revhost = xmalloc_sockaddr2hostonly_noport(cur->ai_addr);
+
+                       printf("Address %u: %s%c", ++cnt, dotted, revhost ? ' ' : '\n');
+                       if (revhost) {
+                               puts(revhost);
+                               if (ENABLE_FEATURE_CLEAN_UP)
+                                       free(revhost);
+                       }
+                       if (ENABLE_FEATURE_CLEAN_UP)
+                               free(dotted);
                        cur = cur->ai_next;
                }
        } else {
-               bb_error_msg("getaddrinfo('%s') failed: %s", hostname, gai_strerror(rc));
+#if ENABLE_VERBOSE_RESOLUTION_ERRORS
+               bb_error_msg("can't resolve '%s': %s", hostname, gai_strerror(rc));
+#else
+               bb_error_msg("can't resolve '%s'", hostname);
+#endif
        }
-       freeaddrinfo(result);
+       if (ENABLE_FEATURE_CLEAN_UP)
+               freeaddrinfo(result);
        return (rc != 0);
 }
 
+/* lookup the default nameserver and display it */
+static void server_print(void)
+{
+       char *server;
+
+       server = xmalloc_sockaddr2dotted_noport((struct sockaddr*)&_res.nsaddr_list[0]);
+       /* I honestly don't know what to do if DNS server has _IPv6 address_.
+        * Probably it is listed in
+        * _res._u._ext_.nsaddrs[MAXNS] (of type "struct sockaddr_in6*" each)
+        * but how to find out whether resolver uses
+        * _res.nsaddr_list[] or _res._u._ext_.nsaddrs[], or both?
+        * Looks like classic design from hell, BIND-grade. Hard to surpass. */
+       print_host(server, "Server:");
+       if (ENABLE_FEATURE_CLEAN_UP)
+               free(server);
+       bb_putchar('\n');
+}
 
 /* alter the global _res nameserver structure to use
    an explicit dns server instead of what is in /etc/resolv.h */
@@ -108,41 +127,28 @@ static void set_default_dns(char *server)
        }
 }
 
-
-/* lookup the default nameserver and display it */
-static void server_print(void)
-{
-       char str[INET6_ADDRSTRLEN];
-
-       sockaddr_to_dotted((struct sockaddr*)&_res.nsaddr_list[0], str, sizeof(str));
-       print_host(str, "Server:");
-       puts("");
-}
-
-
+int nslookup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int nslookup_main(int argc, char **argv)
 {
-       /*
-       * initialize DNS structure _res used in printing the default
-       * name server and in the explicit name server option feature.
-       */
-
-       res_init();
-
-       /*
-       * We allow 1 or 2 arguments.
-       * The first is the name to be looked up and the second is an
-       * optional DNS server with which to do the lookup.
-       * More than 3 arguments is an error to follow the pattern of the
-       * standard nslookup
-       */
+       /* We allow 1 or 2 arguments.
+        * The first is the name to be looked up and the second is an
+        * optional DNS server with which to do the lookup.
+        * More than 3 arguments is an error to follow the pattern of the
+        * standard nslookup */
 
        if (argc < 2 || *argv[1] == '-' || argc > 3)
                bb_show_usage();
-       else if(argc == 3)
+
+       /* initialize DNS structure _res used in printing the default
+        * name server and in the explicit name server option feature. */
+       res_init();
+       /* rfc2133 says this enables IPv6 lookups */
+       /* (but it also says "may be enabled in /etc/resolv.conf|) */
+       /*_res.options |= RES_USE_INET6;*/
+
+       if (argc == 3)
                set_default_dns(argv[2]);
 
        server_print();
-       return print_host(argv[1], "Name:  ");
+       return print_host(argv[1], "Name:");
 }
-