1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2001 Brian Somers <[email protected]>
5 * Based on original work by Atsushi Murai <[email protected]>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 */
30
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33
34 #include <sys/param.h>
35
36 #include <libutil.h>
37 #include <string.h>
38 #include <unistd.h>
39
40 static 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 */
55 void
trimdomain(char * fullhost,int hostsize)56 trimdomain(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 if ((s = memchr(s, '.', (size_t)(end - s))) != NULL) {
81 if (strncasecmp(s + 1, domain, dlen) == 0) {
82 if (s[dlen + 1] == '\0') {
83 /* Found -- lose the domain. */
84 *s = '\0';
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 }
91 }
92 }
93 }
94
95 /*
96 * Is the given string NN or NN.NN where ``NN'' is an all-numeric string ?
97 */
98 static int
isDISP(const char * disp)99 isDISP(const char *disp)
100 {
101 size_t w;
102 int res;
103
104 w = strspn(disp, "0123456789");
105 res = 0;
106 if (w > 0) {
107 if (disp[w] == '\0')
108 res = 1; /* NN */
109 else if (disp[w] == '.') {
110 disp += w + 1;
111 w = strspn(disp, "0123456789");
112 if (w > 0 && disp[w] == '\0')
113 res = 1; /* NN.NN */
114 }
115 }
116 return (res);
117 }
118