ahost should use ares_getaddrinfo() these days (#669)

ahost wasn't printing both ipv4 and ipv6 addresses. This day and age, it really should.

This PR also adds the ability to specify the servers to use.

Fix By: Brad House (@bradh352)

docs/ahost.1

@@ -39,11 +39,14 @@ Print some extra debugging output.
 Display this help and exit.
 .TP
 \fB\-t\fR type
-If type is "a", print the A record (default).
+If type is "a", print the A record.
 If type is "aaaa", print the AAAA record.
-If type is "u", look for either AAAA or A record (in that order).
+If type is "u", look for both AAAA and A records (default).
 .TP
-\fB\-s\fR \fIdomain\fP
+\fB\-s\fR server
+Set the server list to use for DNS lookups.
+.TP
+\fB\-D\fR \fIdomain\fP
 Specify the \fIdomain\fP to search instead of using the default values from
 .br
 /etc/resolv.conf. This option only has an effect on platforms that use

src/tools/ahost.c

@@ -58,6 +58,8 @@
 #endif
 
 static void callback(void *arg, int status, int timeouts, struct hostent *host);
+static void ai_callback(void *arg, int status, int timeouts,
+                        struct ares_addrinfo *result);
 static void usage(void);
 static void print_help_info_ahost(void);
 
@@ -69,7 +71,7 @@ int         main(int argc, char **argv)
   int                  status;
   int                  nfds;
   int                  c;
-  int                  addr_family = AF_INET;
+  int                  addr_family = AF_UNSPEC;
   fd_set               read_fds;
   fd_set               write_fds;
   struct timeval      *tvp;
@@ -77,6 +79,7 @@ int         main(int argc, char **argv)
   struct in_addr       addr4;
   struct ares_in6_addr addr6;
   ares_getopt_state_t  state;
+  char                *servers = NULL;
 
 #ifdef USE_WINSOCK
   WORD    wVersionRequested = MAKEWORD(USE_WINSOCK, USE_WINSOCK);
@@ -93,14 +96,14 @@ int         main(int argc, char **argv)
   }
 
   ares_getopt_init(&state, argc, (const char **)argv);
-  while ((c = ares_getopt(&state, "dt:h?s:")) != -1) {
+  while ((c = ares_getopt(&state, "dt:h?D:s:")) != -1) {
     switch (c) {
       case 'd':
 #ifdef WATT32
         dbug_init();
 #endif
         break;
-      case 's':
+      case 'D':
         optmask |= ARES_OPT_DOMAINS;
         options.ndomains++;
         options.domains = (char **)realloc(
@@ -118,9 +121,18 @@ int         main(int argc, char **argv)
           usage();
         }
         break;
-      case 'h':
+      case 's':
-        print_help_info_ahost();
+        if (state.optarg == NULL) {
+          fprintf(stderr, "%s", "missing servers");
+          usage();
+          break;
+        }
+        if (servers) {
+          free(servers);
+        }
+        servers = strdup(state.optarg);
         break;
+      case 'h':
       case '?':
         print_help_info_ahost();
         break;
@@ -138,10 +150,22 @@ int         main(int argc, char **argv)
 
   status = ares_init_options(&channel, &options, optmask);
   if (status != ARES_SUCCESS) {
+    free(servers);
     fprintf(stderr, "ares_init: %s\n", ares_strerror(status));
     return 1;
   }
 
+  if (servers) {
+    status = ares_set_servers_csv(channel, servers);
+    if (status != ARES_SUCCESS) {
+      fprintf(stderr, "ares_set_serveres_csv: %s\n", ares_strerror(status));
+      free(servers);
+      usage();
+      return 1;
+    }
+    free(servers);
+  }
+
   /* Initiate the queries, one per command-line argument. */
   for (; *argv; argv++) {
     if (ares_inet_pton(AF_INET, *argv, &addr4) == 1) {
@@ -151,7 +175,10 @@ int         main(int argc, char **argv)
       ares_gethostbyaddr(channel, &addr6, sizeof(addr6), AF_INET6, callback,
                          *argv);
     } else {
-      ares_gethostbyname(channel, *argv, addr_family, callback, *argv);
+      struct ares_addrinfo_hints hints;
+      memset(&hints, 0, sizeof(hints));
+      hints.ai_family = addr_family;
+      ares_getaddrinfo(channel, *argv, NULL, &hints, ai_callback, *argv);
     }
   }
 
@@ -202,25 +229,47 @@ static void callback(void *arg, int status, int timeouts, struct hostent *host)
 
     ares_inet_ntop(host->h_addrtype, *p, addr_buf, sizeof(addr_buf));
     printf("%-32s\t%s", host->h_name, addr_buf);
-#if 0
-      if (host->h_aliases[0])
-        {
-           int i;
-
-           printf (", Aliases: ");
-           for (i = 0; host->h_aliases[i]; i++)
-               printf("%s ", host->h_aliases[i]);
-        }
-#endif
     puts("");
   }
 }
 
+static void ai_callback(void *arg, int status, int timeouts,
+                        struct ares_addrinfo *result)
+{
+  struct ares_addrinfo_node *node = NULL;
+  (void)timeouts;
+
+
+  if (status != ARES_SUCCESS) {
+    fprintf(stderr, "%s: %s\n", (char *)arg, ares_strerror(status));
+    return;
+  }
+
+  for (node = result->nodes; node != NULL; node = node->ai_next) {
+    char        addr_buf[64] = "";
+    const void *ptr          = NULL;
+    if (node->ai_family == AF_INET) {
+      struct sockaddr_in *in_addr =
+        (struct sockaddr_in *)((void *)node->ai_addr);
+      ptr = &in_addr->sin_addr;
+    } else if (node->ai_family == AF_INET6) {
+      struct sockaddr_in6 *in_addr =
+        (struct sockaddr_in6 *)((void *)node->ai_addr);
+      ptr = &in_addr->sin6_addr;
+    } else {
+      continue;
+    }
+    ares_inet_ntop(node->ai_family, ptr, addr_buf, sizeof(addr_buf));
+    printf("%-32s\t%s\n", result->name, addr_buf);
+  }
+
+  ares_freeaddrinfo(result);
+}
+
 static void usage(void)
 {
-  fprintf(
+  fprintf(stderr, "usage: ahost [-h] [-d] [[-D {domain}] ...] [-s {server}] "
-    stderr,
+                  "[-t {a|aaaa|u}] {host|addr} ...\n");
-    "usage: ahost [-h] [-d] [-s {domain}] [-t {a|aaaa|u}] {host|addr} ...\n");
   exit(1);
 }
 
@@ -229,19 +278,18 @@ static void print_help_info_ahost(void)
 {
   printf("ahost, version %s\n\n", ARES_VERSION_STR);
   printf(
-    "usage: ahost [-h] [-d] [[-s domain] ...] [-t a|aaaa|u] host|addr ...\n\n"
+    "usage: ahost [-h] [-d] [-D domain] [-s server] [-t a|aaaa|u] host|addr "
-    "  h : Display this help and exit.\n"
+    "...\n\n"
-    "  d : Print some extra debugging output.\n\n"
+    "  -h : Display this help and exit.\n"
-    "  s domain : Specify the domain to search instead of using the default "
+    "  -d : Print some extra debugging output.\n\n"
+    "  -D domain : Specify the domain to search instead of using the default "
     "values\n"
-    "               from /etc/resolv.conf. This option only has an effect on\n"
+    "  -s server : Connect to the specified DNS server, instead of the\n"
-    "               platforms that use /etc/resolv.conf for DNS "
+    "              system's default one(s). Servers are tried in round-robin,\n"
-    "configuration;\n"
+    "              if the previous one failed.\n"
-    "               it has no effect on other platforms (such as Win32 or "
+    "  -t type   : If type is \"a\", print the A record.\n"
-    "Android).\n\n"
+    "              If type is \"aaaa\", print the AAAA record.\n"
-    "  t type   : If type is \"a\", print the A record (default).\n"
+    "              If type is \"u\" (default), print both A and AAAA records.\n"
-    "               If type is \"aaaa\", print the AAAA record.\n"
+    "\n");
-    "               If type is \"u\", look for either AAAA or A record (in "
-    "that order).\n\n");
   exit(0);
 }