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
  30 #ifdef SPRINTF_CHAR
  31 # define SPRINTF(x) strlen(sprintf/**/x)
  32 #else
  33 # define SPRINTF(x) ((size_t)sprintf x)
  34 #endif
  35
  36 /*
  37  * char *
  38  * inet_neta(src, dst, size)
  39  *      format a u_long network number into presentation format.
  40  * return:
  41  *      pointer to dst, or NULL if an error occurred (check errno).
  42  * note:
  43  *      format of ``src'' is as for inet_network().
  44  * author:
  45  *      Paul Vixie (ISC), July 1996
  46  */
  47 char *
  48 inet_neta(src, dst, size)
  49         u_long src;
  50         char *dst;
  51         size_t size;
  52 {
  53         char *odst = dst;
  54         char *tp;
  55
  56         while (src & 0xffffffff) {
  57                 u_char b = (src & 0xff000000) >> 24;
  58
  59                 src <<= 8;
  60                 if (b) {
  61                         if (size < sizeof "255.")
  62                                 goto emsgsize;
  63                         tp = dst;
  64                         dst += SPRINTF((dst, "%u", b));
  65                         if (src != 0L) {
  66                                 *dst++ = '.';
  67                                 *dst = '\0';
  68                         }
  69                         size -= (size_t)(dst - tp);
  70                 }
  71         }
  72         if (dst == odst) {
  73                 if (size < sizeof "0.0.0.0")
  74                         goto emsgsize;
  75                 strcpy(dst, "0.0.0.0");
  76         }
  77         return (odst);
  78
  79  emsgsize:
  80         errno = EMSGSIZE;
  81         return (NULL);
  82 }