--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toys/pending/host.c	Sun Jun 08 15:03:32 2014 -0500
@@ -0,0 +1,251 @@
+/* host.c - DNS lookup utility
+ *
+ * Copyright 2014 Rich Felker <dalias@aerifal.cx>
+ *
+ * No standard, but there's a version in bind9
+
+USE_HOST(NEWTOY(host, "<1>2avt:", TOYFLAG_USR|TOYFLAG_BIN))
+
+config HOST
+  bool "host"
+  default n
+  help
+    usage: host [-av] [-t TYPE] NAME [SERVER]
+
+    Perform DNS lookup on NAME, which can be a domain name to lookup,
+    or an ipv4 dotted or ipv6 colon seprated address to reverse lookup.
+    SERVER (if present) is the DNS server to use.
+
+    -a	no idea
+    -t	not a clue
+    -v	verbose
+*/
+
+#define FOR_host
+#include "toys.h"
+
+GLOBALS(
+  char *type_str;
+)
+
+#include <resolv.h>
+
+#define PL_IP 1
+#define PL_NAME 2
+#define PL_DATA 3
+#define PL_TEXT 4
+#define PL_SOA 5
+#define PL_MX 6
+#define PL_SRV 7
+
+static const struct rrt {
+  const char *name;
+  const char *msg;
+  int pl;
+  int af;
+} rrt[] = {
+  [1] = { "A", "has address", PL_IP, AF_INET },
+  [28] = { "AAAA", "has address", PL_IP, AF_INET6 },
+  [2] = { "NS", "name server", PL_NAME },
+  [5] = { "CNAME", "is a nickname for", PL_NAME },
+  [16] = { "TXT", "descriptive text", PL_TEXT },
+  [6] = { "SOA", "start of authority", PL_SOA },
+  [12] = { "PTR", "domain name pointer", PL_NAME },
+  [15] = { "MX", "mail is handled", PL_MX },
+  [33] = { "SRV", "mail is handled", PL_SRV },
+  [255] = { "*", 0, 0 },
+};
+
+static const char rct[16][32] = {
+  "Success",
+  "Format error",
+  "Server failure",
+  "Non-existant domain",
+  "Not implemented",
+  "Refused",
+};
+
+void host_main(void)
+{
+  int verbose=(toys.optflags & (FLAG_a|FLAG_v)), type;
+  char *name, *nsname;
+  int i, j, ret, sec, count, rcode, qlen, alen, pllen = 0, v[5];
+  unsigned ttl, pri;
+  unsigned char qbuf[280], abuf[512], *p;
+  char rrname[256], plname[640], ptrbuf[64];
+  struct addrinfo *ai, iplit_hints = { .ai_flags = AI_NUMERICHOST };
+
+  name = *toys.optargs;
+  nsname = toys.optargs[1];
+
+  if (!TT.type_str && (toys.optflags & FLAG_a)) TT.type_str = "255";
+  if (!getaddrinfo(name, 0, &iplit_hints, &ai)) {
+    switch (ai->ai_family) {
+      unsigned char *a;
+      static const char xdigits[] = "0123456789abcdef";
+    case AF_INET:
+      a = (void *)&((struct sockaddr_in *)ai->ai_addr)->sin_addr;
+      snprintf(ptrbuf, sizeof ptrbuf,
+        "%d.%d.%d.%d.in-addr.arpa",
+        a[3], a[2], a[1], a[0]);
+      break;
+    case AF_INET6:
+      a = (void *)&((struct sockaddr_in6 *)ai->ai_addr)->sin6_addr;
+      for (j=0, i=15; i>=0; i--) {
+        ptrbuf[j++] = xdigits[a[i]&15];
+        ptrbuf[j++] = '.';
+        ptrbuf[j++] = xdigits[a[i]>>4];
+        ptrbuf[j++] = '.';
+      }
+      strcpy(ptrbuf+j, "ip6.arpa");
+      break;
+    }
+    name = ptrbuf;
+    if (!TT.type_str) TT.type_str="12";
+  } else {
+    if (!TT.type_str) TT.type_str="1";
+  }
+
+  if (TT.type_str[0]-'0' < 10u) {
+    type = atoi(TT.type_str);
+  } else {
+    type = -1;
+    for (i=0; i < sizeof rrt / sizeof *rrt; i++) {
+      if (rrt[i].name && !strcasecmp(TT.type_str, rrt[i].name)) {
+        type = i;
+        break;
+      }
+    }
+    if (!strcasecmp(TT.type_str, "any")) type = 255;
+    if (type < 0) {
+      fprintf(stderr, "Invalid query type: %s\n", TT.type_str);
+      goto out_error;
+    }
+  }
+
+  qlen = res_mkquery(0, name, 1, type, 0, 0, 0, qbuf, sizeof qbuf);
+  if (qlen < 0) {
+    fprintf(stderr, "Invalid query parameters: %s", name);
+    goto out_error;
+  }
+
+  if (nsname) {
+    struct addrinfo ns_hints = { .ai_socktype = SOCK_DGRAM };
+    if ((ret = getaddrinfo(nsname, "53", &ns_hints, &ai)) < 0) {
+      fprintf(stderr, "Error looking up server name: %s\n",
+        gai_strerror(ret));
+      goto out_error;
+    }
+    int s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+    if (s < 0 || connect(s, ai->ai_addr, ai->ai_addrlen) < 0) {
+      fprintf(stderr, "Socket error: %s\n", strerror(errno));
+      goto out_error;
+    }
+    setsockopt(s, SOL_SOCKET, SO_RCVTIMEO,
+      &(struct timeval){ .tv_sec = 5 },
+      sizeof (struct timeval));
+    printf("Using domain server %s:\n", nsname);
+    send(s, qbuf, qlen, 0);
+    alen = recv(s, abuf, sizeof abuf, 0);
+  } else {
+    alen = res_send(qbuf, qlen, abuf, sizeof abuf);
+  }
+
+  if (alen < 12) {
+    fprintf(stderr, "Host not found, try again.\n");
+    goto out_error;
+  }
+
+  rcode = abuf[3] & 15;
+
+  if (verbose) {
+    printf("rcode = %d (%s), ancount = %d\n",
+      rcode, rct[rcode], 256*abuf[6] + abuf[7]);
+    if (!(abuf[2] & 4))
+      printf("The following answer is not authoritative:\n");
+  }
+
+  if (rcode) {
+    fprintf(stderr, "Host not found.\n");
+    if (!verbose) goto out_error;
+  }
+
+  p = abuf + 12;
+  for (sec=0; sec<4; sec++) {
+    count = 256*abuf[4+2*sec] + abuf[5+2*sec];
+    if (verbose && count>0 && sec>1) {
+      puts(sec==2 ? "For authoritative answers, see:"
+        : "Additional information:");
+    }
+    for (; count--; p += pllen) {
+      p += dn_expand(abuf, abuf+alen, p, rrname, sizeof rrname);
+      type = 256*p[0] + p[1];
+      p += 4;
+      if (!sec) continue;
+      ttl = 16777216*p[0] + 65536*p[1] + 256*p[2] + p[3];
+      p += 4;
+      pllen = 256*p[0] + p[1];
+      p += 2;
+      switch (type<sizeof rrt/sizeof *rrt ? rrt[type].pl : 0) {
+      case PL_IP:
+        inet_ntop(rrt[type].af, p, plname, sizeof plname);
+        break;
+      case PL_NAME:
+        dn_expand(abuf, abuf+alen, p, plname, sizeof plname);
+        break;
+      case PL_TEXT:
+        snprintf(plname, sizeof plname, "\"%.*s\"", pllen, p);
+        break;
+      case PL_SOA:
+        i = dn_expand(abuf, abuf+alen, p, plname, sizeof plname - 1);
+        strcat(plname, " ");
+        i += dn_expand(abuf, abuf+alen, p+i, plname+strlen(plname),
+          sizeof plname-strlen(plname));
+        for (j=0; j<5; j++)
+          v[j] = 16777216*p[i+4*j] + 65536*p[1+i+4*j]
+            + 256*p[2+i+4*j] + p[3+i+4*j];
+        snprintf(plname+strlen(plname),
+          sizeof plname-strlen(plname),
+          "(\n\t\t%zu\t;serial (version)\n"
+          "\t\t%zu\t;refresh period\n"
+          "\t\t%zu\t;retry interval\n"
+          "\t\t%zu\t;expire time\n"
+          "\t\t%zu\t;default ttl\n"
+          "\t\t)", v[0], v[1], v[2], v[3], v[4]);
+        break;
+      case PL_MX:
+        pri = 256*p[0] + p[1];
+        snprintf(plname, sizeof plname,
+          verbose ? "%d " : "(pri=%d) by ", pri);
+        dn_expand(abuf, abuf+alen, p+2,
+          plname+strlen(plname),
+          sizeof plname - strlen(plname));
+        break;
+      case PL_SRV:
+        for (j=0; j<3; j++)
+          v[j] = 256*p[2*j] + p[1+2*j];
+        snprintf(plname, sizeof plname,
+          "%d %d %d ", v[0], v[1], v[2]);
+        dn_expand(abuf, abuf+alen, p+6,
+          plname+strlen(plname),
+          sizeof plname - strlen(plname));
+        break;
+      default:
+        printf("%s unsupported RR type %u\n", rrname, type);
+        continue;
+      }
+      if (verbose) {
+        printf("%s\t%u\t%s %s\t%s\n",
+          rrname, ttl, "IN", rrt[type].name, plname);
+      } else if (rrt[type].msg) {
+        printf("%s %s %s\n", rrname, rrt[type].msg, plname);
+      }
+    }
+    if (!verbose && sec==1) break;
+  }
+  toys.exitval = rcode;
+  return;
+
+out_error:
+  toys.exitval = 1;
+}