1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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/param.h> 32 33 #include <libutil.h> 34 #include <string.h> 35 #include <unistd.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 if ((s = memchr(s, '.', (size_t)(end - s))) != NULL) { 78 if (strncasecmp(s + 1, domain, dlen) == 0) { 79 if (s[dlen + 1] == '\0') { 80 /* Found -- lose the domain. */ 81 *s = '\0'; 82 } else if (s[dlen + 1] == ':' && 83 isDISP(s + dlen + 2) && 84 (len = strlen(s + dlen + 1)) < (size_t)(end - s)) { 85 /* Found -- shuffle the DISPLAY back. */ 86 memmove(s, s + dlen + 1, len + 1); 87 } 88 } 89 } 90 } 91 92 /* 93 * Is the given string NN or NN.NN where ``NN'' is an all-numeric string ? 94 */ 95 static int 96 isDISP(const char *disp) 97 { 98 size_t w; 99 int res; 100 101 w = strspn(disp, "0123456789"); 102 res = 0; 103 if (w > 0) { 104 if (disp[w] == '\0') 105 res = 1; /* NN */ 106 else if (disp[w] == '.') { 107 disp += w + 1; 108 w = strspn(disp, "0123456789"); 109 if (w > 0 && disp[w] == '\0') 110 res = 1; /* NN.NN */ 111 } 112 } 113 return (res); 114 } 115