Changeset 2725 in MondoRescue for branches/2.2.9/mindi-busybox/networking/nslookup.c

Timestamp:

Feb 25, 2011, 9:26:54 PM (13 years ago)

Author:

Bruno Cornec

Message:

• Update mindi-busybox to 1.18.3 to avoid problems with the tar command which is now failing on recent versions with busybox 1.7.3

File:

• branches/2.2.9/mindi-busybox/networking/nslookup.c (modified) (7 diffs)

branches/2.2.9/mindi-busybox/networking/nslookup.c

@@ -9 +9 @@
  * added by Ben Zeckel <bzeckel@hmc.edu> June 2001
  *
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
@@ -16 +16 @@
 
 /*
- *  I'm only implementing non-interactive mode;
- *  I totally forgot nslookup even had an interactive mode.
+ * I'm only implementing non-interactive mode;
+ * I totally forgot nslookup even had an interactive mode.
+ *
+ * This applet is the only user of res_init(). Without it,
+ * you may avoid pulling in _res global from libc.
  */
 
@@ -52 +55 @@
     /* We can't use xhost2sockaddr() - we want to get ALL addresses,
      * not just one */
-
     struct addrinfo *result = NULL;
     int rc;
@@ -70 +72 @@
 
         printf("%-10s %s\n", header, hostname);
-        // printf("%s\n", cur->ai_canonname); ?
+        // puts(cur->ai_canonname); ?
         while (cur) {
             char *dotted, *revhost;
@@ -102 +104 @@
 {
     char *server;
+    struct sockaddr *sa;
 
-    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. */
+#if ENABLE_FEATURE_IPV6
+    sa = (struct sockaddr*)_res._u._ext.nsaddrs[0];
+    if (!sa)
+#endif
+        sa = (struct sockaddr*)&_res.nsaddr_list[0];
+    server = xmalloc_sockaddr2dotted_noport(sa);
+
     print_host(server, "Server:");
     if (ENABLE_FEATURE_CLEAN_UP)
         free(server);
-    puts("");
+    bb_putchar('\n');
 }
 
 /* alter the global _res nameserver structure to use
-   an explicit dns server instead of what is in /etc/resolv.h */
-static void set_default_dns(char *server)
+   an explicit dns server instead of what is in /etc/resolv.conf */
+static void set_default_dns(const char *server)
 {
-    struct in_addr server_in_addr;
+    len_and_sockaddr *lsa;
 
-    if (inet_pton(AF_INET, server, &server_in_addr) > 0) {
+    /* NB: this works even with, say, "[::1]:5353"! :) */
+    lsa = xhost2sockaddr(server, 53);
+
+    if (lsa->u.sa.sa_family == AF_INET) {
         _res.nscount = 1;
-        _res.nsaddr_list[0].sin_addr = server_in_addr;
+        /* struct copy */
+        _res.nsaddr_list[0] = lsa->u.sin;
     }
+#if ENABLE_FEATURE_IPV6
+    /* Hoped libc can cope with IPv4 address there too.
+     * No such luck, glibc 2.4 segfaults even with IPv6,
+     * maybe I misunderstand how to make glibc use IPv6 addr?
+     * (uclibc 0.9.31+ should work) */
+    if (lsa->u.sa.sa_family == AF_INET6) {
+        // glibc neither SEGVs nor sends any dgrams with this
+        // (strace shows no socket ops):
+        //_res.nscount = 0;
+        _res._u._ext.nscount = 1;
+        /* store a pointer to part of malloc'ed lsa */
+        _res._u._ext.nsaddrs[0] = &lsa->u.sin6;
+        /* must not free(lsa)! */
+    }
+#endif
 }
 
-int nslookup_main(int argc, char **argv);
+int nslookup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int nslookup_main(int argc, char **argv)
 {
@@ -136 +158 @@
      * More than 3 arguments is an error to follow the pattern of the
      * standard nslookup */
-
-    if (argc < 2 || *argv[1] == '-' || argc > 3)
+    if (!argv[1] || argv[1][0] == '-' || argc > 3)
         bb_show_usage();
 
@@ -144 +165 @@
     res_init();
     /* rfc2133 says this enables IPv6 lookups */
-    /* (but it also says "may be enabled in /etc/resolv.conf|) */
+    /* (but it also says "may be enabled in /etc/resolv.conf") */
     /*_res.options |= RES_USE_INET6;*/
 
-    if (argc == 3)
+    if (argv[2])
         set_default_dns(argv[2]);