external/ibm-public/postfix/dist/src/dns/dns_strerror.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      dns_strerror 3
   6 /* SUMMARY
   7 /*      name service lookup error code to string
   8 /* SYNOPSIS
   9 /*      #include <dhs.h>
  10 /*
  11 /*      const char *dns_strerror(code)
  12 /*      int     code;
  13 /* DESCRIPTION
  14 /*      dns_strerror() maps a name service lookup error to printable string.
  15 /*      The result is for read-only purposes, and unknown codes share a
  16 /*      common string buffer.
  17 /* LICENSE
  18 /* .ad
  19 /* .fi
  20 /*      The Secure Mailer license must be distributed with this software.
  21 /* AUTHOR(S)
  22 /*      Wietse Venema
  23 /*      IBM T.J. Watson Research
  24 /*      P.O. Box 704
  25 /*      Yorktown Heights, NY 10598, USA
  26 /*--*/
  27
  28 /* System library. */
  29
  30 #include <sys_defs.h>
  31 #include <netdb.h>
  32
  33 /* Utility library. */
  34
  35 #include <vstring.h>
  36
  37 /* DNS library. */
  38
  39 #include "dns.h"
  40
  41  /*
  42   * Mapping from error code to printable string. The herror() routine does
  43   * something similar, but has output only to the stderr stream.
  44   */
  45 struct dns_error_map {
  46     unsigned error;
  47     const char *text;
  48 };
  49
  50 static struct dns_error_map dns_error_map[] = {
  51     HOST_NOT_FOUND, "Host not found",
  52     TRY_AGAIN, "Host not found, try again",
  53     NO_RECOVERY, "Non-recoverable error",
  54     NO_DATA, "Host found but no data record of requested type",
  55 };
  56
  57 /* dns_strerror - map resolver error code to printable string */
  58
  59 const char *dns_strerror(unsigned error)
  60 {
  61     static VSTRING *unknown = 0;
  62     unsigned i;
  63
  64     for (i = 0; i < sizeof(dns_error_map) / sizeof(dns_error_map[0]); i++)
  65         if (dns_error_map[i].error == error)
  66             return (dns_error_map[i].text);
  67     if (unknown == 0)
  68         unknown = vstring_alloc(sizeof("Unknown error XXXXXX"));
  69     vstring_sprintf(unknown, "Unknown error %u", error);
  70     return (vstring_str(unknown));
  71 }