resolv/inet_neta.c

   1 /*
   2  * Copyright (c) 1996 by Internet Software Consortium.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
   9  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  10  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  11  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  12  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  13  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  14  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  15  * SOFTWARE.
  16  */
  17
  18 #if defined(LIBC_SCCS) && !defined(lint)
  19 static const char rcsid[] = "$Id$";
  20 #endif
  21
  22 #include <sys/types.h>
  23 #include <sys/socket.h>
  24 #include <netinet/in.h>
  25 #include <arpa/inet.h>
  26
  27 #include <errno.h>
  28 #include <stdio.h>
  29 #include <string.h>
  30
  31 #ifdef SPRINTF_CHAR
  32 # define SPRINTF(x) strlen(sprintf/**/x)
  33 #else
  34 # define SPRINTF(x) ((size_t)sprintf x)
  35 #endif
  36
  37 /*
  38  * char *
  39  * inet_neta(src, dst, size)
  40  *      format a u_long network number into presentation format.
  41  * return:
  42  *      pointer to dst, or NULL if an error occurred (check errno).
  43  * note:
  44  *      format of ``src'' is as for inet_network().
  45  * author:
  46  *      Paul Vixie (ISC), July 1996
  47  */
  48 char *
  49 inet_neta(src, dst, size)
  50         u_int32_t src;
  51         char *dst;
  52         size_t size;
  53 {
  54         char *odst = dst;
  55         char *tp;
  56
  57         while (src & 0xffffffff) {
  58                 u_char b = (src & 0xff000000) >> 24;
  59
  60                 src <<= 8;
  61                 if (b) {
  62                         if (size < sizeof "255.")
  63                                 goto emsgsize;
  64                         tp = dst;
  65                         dst += SPRINTF((dst, "%u", b));
  66                         if (src != 0L) {
  67                                 *dst++ = '.';
  68                                 *dst = '\0';
  69                         }
  70                         size -= (size_t)(dst - tp);
  71                 }
  72         }
  73         if (dst == odst) {
  74                 if (size < sizeof "0.0.0.0")
  75                         goto emsgsize;
  76                 strcpy(dst, "0.0.0.0");
  77         }
  78         return (odst);
  79
  80  emsgsize:
  81         __set_errno (EMSGSIZE);
  82         return (NULL);
  83 }