resolv/herror.c

   1 /*
   2  * Copyright (c) 1987 Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #if defined(LIBC_SCCS) && !defined(lint)
  35 static char sccsid[] = "@(#)herror.c    6.6 (Berkeley) 2/24/91";
  36 #endif /* LIBC_SCCS and not lint */
  37
  38 #include <sys/types.h>
  39 #include <sys/uio.h>
  40 #include <netdb.h>
  41 #include <unistd.h>
  42 #include <string.h>
  43
  44 char    *h_errlist[] = {
  45         "Error 0",
  46         "Unknown host",                         /* 1 HOST_NOT_FOUND */
  47         "Host name lookup failure",             /* 2 TRY_AGAIN */
  48         "Unknown server error",                 /* 3 NO_RECOVERY */
  49         "No address associated with name",      /* 4 NO_ADDRESS */
  50 };
  51 int     h_nerr = { sizeof(h_errlist)/sizeof(h_errlist[0]) };
  52
  53 extern int      h_errno;
  54
  55 /*
  56  * herror --
  57  *      print the error indicated by the h_errno value.
  58  */
  59 void
  60 herror(s)
  61         const char *s;
  62 {
  63         struct iovec iov[4];
  64         register struct iovec *v = iov;
  65
  66         if (s && *s) {
  67                 v->iov_base = (char *)s;
  68                 v->iov_len = strlen(s);
  69                 v++;
  70                 v->iov_base = ": ";
  71                 v->iov_len = 2;
  72                 v++;
  73         }
  74         v->iov_base = (u_int)h_errno < h_nerr ?
  75             h_errlist[h_errno] : "Unknown error";
  76         v->iov_len = strlen(v->iov_base);
  77         v++;
  78         v->iov_base = "\n";
  79         v->iov_len = 1;
  80         writev(STDERR_FILENO, iov, (v - iov) + 1);
  81 }