xref: /dragonfly/lib/libutil/trimdomain.c (revision 25a2db75)
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  * $FreeBSD: /repoman/r/ncvs/src/lib/libutil/trimdomain.c,v 1.5 2003/10/18 10:04:16 markm Exp $
28  */
29 
30 #include <sys/param.h>
31 
32 #include <string.h>
33 #include <unistd.h>
34 
35 #include "libutil.h"
36 
37 static int	isDISP(const char *);
38 
39 /*-
40  * Trim the current domain name from fullhost, but only if the result
41  * is less than or equal to hostsize in length.
42  *
43  * This function understands $DISPLAY type fullhosts.
44  *
45  * For example:
46  *
47  *     trimdomain("abcde.my.domain", 5)       ->   "abcde"
48  *     trimdomain("abcde.my.domain", 4)       ->   "abcde.my.domain"
49  *     trimdomain("abcde.my.domain:0.0", 9)   ->   "abcde:0.0"
50  *     trimdomain("abcde.my.domain:0.0", 8)   ->   "abcde.my.domain:0.0"
51  */
52 void
53 trimdomain(char *fullhost, int hostsize)
54 {
55 	static size_t dlen;
56 	static int first = 1;
57 	static char domain[MAXHOSTNAMELEN];
58 	char *end, *s;
59 	size_t len;
60 
61 	if (first) {
62 		/* XXX: Should we assume that our domain is this persistent ? */
63 		first = 0;
64 		if (gethostname(domain, sizeof(domain) - 1) == 0 &&
65 		    (s = strchr(domain, '.')) != NULL)
66 			memmove(domain, s + 1, strlen(s + 1) + 1);
67 		else
68 			domain[0] = '\0';
69 		dlen = strlen(domain);
70 	}
71 
72 	if (domain[0] == '\0')
73 		return;
74 
75 	s = fullhost;
76 	end = s + hostsize + 1;
77 	for (; (s = memchr(s, '.', (size_t)(end - s))) != NULL; s++) {
78 		if (strncasecmp(s + 1, domain, dlen) == 0) {
79 			if (s[dlen + 1] == '\0') {
80 				/* Found -- lose the domain. */
81 				*s = '\0';
82 				break;
83 			} else if (s[dlen + 1] == ':' &&
84 			    isDISP(s + dlen + 2) &&
85 			    (len = strlen(s + dlen + 1)) < (size_t)(end - s)) {
86 				/* Found -- shuffle the DISPLAY back. */
87 				memmove(s, s + dlen + 1, len + 1);
88 				break;
89 			}
90 		}
91 	}
92 }
93 
94 /*
95  * Is the given string NN or NN.NN where ``NN'' is an all-numeric string ?
96  */
97 static int
98 isDISP(const char *disp)
99 {
100 	size_t w;
101 	int res;
102 
103 	w = strspn(disp, "0123456789");
104 	res = 0;
105 	if (w > 0) {
106 		if (disp[w] == '\0')
107 			res = 1;	/* NN */
108 		else if (disp[w] == '.') {
109 			disp += w + 1;
110 			w = strspn(disp, "0123456789");
111 			if (w > 0 && disp[w] == '\0')
112 				res = 1;	/* NN.NN */
113 		}
114 	}
115 	return (res);
116 }
117