* Correct default name server display and explicit name server option
* 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.
*/
+//usage:#define nslookup_trivial_usage
+//usage: "[HOST] [SERVER]"
+//usage:#define nslookup_full_usage "\n\n"
+//usage: "Query the nameserver for the IP address of the given HOST\n"
+//usage: "optionally using a specified DNS server"
+//usage:
+//usage:#define nslookup_example_usage
+//usage: "$ nslookup localhost\n"
+//usage: "Server: default\n"
+//usage: "Address: default\n"
+//usage: "\n"
+//usage: "Name: debian\n"
+//usage: "Address: 127.0.0.1\n"
+
#include <resolv.h>
#include "libbb.h"
// hint.ai_flags = AI_CANONNAME;
rc = getaddrinfo(hostname, NULL /*service*/, &hint, &result);
- if (!rc) {
+ if (rc == 0) {
struct addrinfo *cur = result;
unsigned cnt = 0;
bb_error_msg("can't resolve '%s'", hostname);
#endif
}
- if (ENABLE_FEATURE_CLEAN_UP)
+ if (ENABLE_FEATURE_CLEAN_UP && result)
freeaddrinfo(result);
return (rc != 0);
}
{
len_and_sockaddr *lsa;
+ if (!server)
+ return;
+
/* NB: this works even with, say, "[::1]:5353"! :) */
lsa = xhost2sockaddr(server, 53);
_res.nsaddr_list[0] = lsa->u.sin;
}
#if ENABLE_FEATURE_IPV6
-// Hoping libc will handle an IPv4 address there too,
-// if it so happens that family is indeed AF_INET
-// if (lsa->u.sa.sa_family == AF_INET6) {
+ /* 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
}
/* (but it also says "may be enabled in /etc/resolv.conf") */
/*_res.options |= RES_USE_INET6;*/
- if (argv[2])
- set_default_dns(argv[2]);
+ set_default_dns(argv[2]);
server_print();
+
+ /* getaddrinfo and friends are free to request a resolver
+ * reinitialization. Just in case, set_default_dns() again
+ * after getaddrinfo (in server_print). This reportedly helps
+ * with bug 675 "nslookup does not properly use second argument"
+ * at least on Debian Wheezy and Openwrt AA (eglibc based).
+ */
+ set_default_dns(argv[2]);
+
return print_host(argv[1], "Name:");
}