trimdomain.c revision 74386 
1/*-
2 * Copyright (c) 2001 Brian Somers <brian@Awfulhak.org>
3 *   Based on original work by Atsushi Murai <amurai@FreeBSD.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 */
28
29#if !defined(lint)
30static const char rcsid[] =
31 "$FreeBSD: head/lib/libutil/trimdomain.c 74386 2001-03-17 10:09:52Z brian $";
32#endif /* not lint */
33
34#include <sys/param.h>
35
36#include <libutil.h>
37#include <string.h>
38#include <unistd.h>
39
40static int	isDISP(const char *);
41
42/*-
43 * Trim the current domain name from fullhost, but only if the result
44 * is less than or equal to hostsize in length.
45 *
46 * This function understands $DISPLAY type fullhosts.
47 *
48 * For example:
49 *
50 *     trimdomain("abcde.my.domain", 5)       ->   "abcde"
51 *     trimdomain("abcde.my.domain", 4)       ->   "abcde.my.domain"
52 *     trimdomain("abcde.my.domain:0.0", 9)   ->   "abcde:0.0"
53 *     trimdomain("abcde.my.domain:0.0", 8)   ->   "abcde.my.domain:0.0"
54 */
55void
56trimdomain(char *fullhost, int hostsize)
57{
58	static size_t dlen;
59	static int first = 1;
60	static char domain[MAXHOSTNAMELEN];
61	char *end, *s;
62	size_t len;
63
64	if (first) {
65		/* XXX: Should we assume that our domain is this persistent ? */
66		first = 0;
67		if (gethostname(domain, sizeof(domain) - 1) == 0 &&
68		    (s = strchr(domain, '.')) != NULL)
69			memmove(domain, s + 1, strlen(s + 1) + 1);
70		else
71			domain[0] = '\0';
72		dlen = strlen(domain);
73	}
74
75	if (domain[0] == '\0')
76		return;
77
78	s = fullhost;
79	end = s + hostsize + 1;
80	for (; (s = memchr(s, '.', end - s)) != NULL; s++) {
81		if (strncasecmp(s + 1, domain, dlen) == 0) {
82			if (s[dlen + 1] == '\0') {
83				/* Found -- lose the domain. */
84				*s = '\0';
85				break;
86			} else if (s[dlen + 1] == ':' &&
87			    isDISP(s + dlen + 2) &&
88			    (len = strlen(s + dlen + 1)) < end - s) {
89				/* Found -- shuffle the DISPLAY back. */
90				memmove(s, s + dlen + 1, len + 1);
91				break;
92			}
93		}
94	}
95}
96
97/*
98 * Is the given string NN or NN.NN where ``NN'' is an all-numeric string ?
99 */
100static int
101isDISP(const char *disp)
102{
103	int res, w;
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}
119