1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2001 Brian Somers <brian@Awfulhak.org> 5 * Based on original work by Atsushi Murai <amurai@FreeBSD.org> 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 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 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