lib/libutil/trimdomain.c

   1 /* $DragonFly: src/lib/libutil/trimdomain.c,v 1.2 2005/03/04 04:31:11 cpressey Exp $ */
   2 /*
   3  * Copyright (c) 2001 Brian Somers <brian@Awfulhak.org>
   4  *   Based on original work by Atsushi Murai <amurai@FreeBSD.org>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  *
  28  * $FreeBSD: /repoman/r/ncvs/src/lib/libutil/trimdomain.c,v 1.5 2003/10/18 10:04:16 markm Exp $
  29  */
  30
  31 #include <sys/cdefs.h>
  32 #include <sys/param.h>
  33
  34 #include <string.h>
  35 #include <unistd.h>
  36
  37 #include "libutil.h"
  38
  39 static int      isDISP(const char *);
  40
  41 /*-
  42  * Trim the current domain name from fullhost, but only if the result
  43  * is less than or equal to hostsize in length.
  44  *
  45  * This function understands $DISPLAY type fullhosts.
  46  *
  47  * For example:
  48  *
  49  *     trimdomain("abcde.my.domain", 5)       ->   "abcde"
  50  *     trimdomain("abcde.my.domain", 4)       ->   "abcde.my.domain"
  51  *     trimdomain("abcde.my.domain:0.0", 9)   ->   "abcde:0.0"
  52  *     trimdomain("abcde.my.domain:0.0", 8)   ->   "abcde.my.domain:0.0"
  53  */
  54 void
  55 trimdomain(char *fullhost, int hostsize)
  56 {
  57         static size_t dlen;
  58         static int first = 1;
  59         static char domain[MAXHOSTNAMELEN];
  60         char *end, *s;
  61         size_t len;
  62
  63         if (first) {
  64                 /* XXX: Should we assume that our domain is this persistent ? */
  65                 first = 0;
  66                 if (gethostname(domain, sizeof(domain) - 1) == 0 &&
  67                     (s = strchr(domain, '.')) != NULL)
  68                         memmove(domain, s + 1, strlen(s + 1) + 1);
  69                 else
  70                         domain[0] = '\0';
  71                 dlen = strlen(domain);
  72         }
  73
  74         if (domain[0] == '\0')
  75                 return;
  76
  77         s = fullhost;
  78         end = s + hostsize + 1;
  79         for (; (s = memchr(s, '.', (size_t)(end - s))) != NULL; s++) {
  80                 if (strncasecmp(s + 1, domain, dlen) == 0) {
  81                         if (s[dlen + 1] == '\0') {
  82                                 /* Found -- lose the domain. */
  83                                 *s = '\0';
  84                                 break;
  85                         } else if (s[dlen + 1] == ':' &&
  86                             isDISP(s + dlen + 2) &&
  87                             (len = strlen(s + dlen + 1)) < (size_t)(end - s)) {
  88                                 /* Found -- shuffle the DISPLAY back. */
  89                                 memmove(s, s + dlen + 1, len + 1);
  90                                 break;
  91                         }
  92                 }
  93         }
  94 }
  95
  96 /*
  97  * Is the given string NN or NN.NN where ``NN'' is an all-numeric string ?
  98  */
  99 static int
 100 isDISP(const char *disp)
 101 {
 102         size_t w;
 103         int res;
 104
 105         w = strspn(disp, "0123456789");
 106         res = 0;
 107         if (w > 0) {
 108                 if (disp[w] == '\0')
 109                         res = 1;        /* NN */
 110                 else if (disp[w] == '.') {
 111                         disp += w + 1;
 112                         w = strspn(disp, "0123456789");
 113                         if (w > 0 && disp[w] == '\0')
 114                                 res = 1;        /* NN.NN */
 115                 }
 116         }
 117         return (res);
 118 }