1 /* $NetBSD: ttyname.c,v 1.19 2003/08/07 16:42:58 agc Exp $ */ 2 3 /* 4 * Copyright (c) 1988, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 #if 0 35 static char sccsid[] = "@(#)ttyname.c 8.2 (Berkeley) 1/27/94"; 36 #else 37 __RCSID("$NetBSD: ttyname.c,v 1.19 2003/08/07 16:42:58 agc Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include "namespace.h" 42 #include <sys/types.h> 43 #include <sys/stat.h> 44 45 #include <assert.h> 46 #include <db.h> 47 #include <dirent.h> 48 #include <errno.h> 49 #include <fcntl.h> 50 #include <paths.h> 51 #include <string.h> 52 #include <termios.h> 53 #include <unistd.h> 54 55 #ifdef __weak_alias 56 __weak_alias(ttyname,_ttyname) 57 #endif 58 59 static char buf[sizeof(_PATH_DEV) + MAXNAMLEN] = _PATH_DEV; 60 static char *oldttyname __P((struct stat *)); 61 62 char * 63 ttyname(fd) 64 int fd; 65 { 66 struct stat sb; 67 struct termios ttyb; 68 DB *db; 69 DBT data, key; 70 struct { 71 mode_t type; 72 dev_t dev; 73 } bkey; 74 75 _DIAGASSERT(fd != -1); 76 77 /* Must be a terminal. */ 78 if (tcgetattr(fd, &ttyb) < 0) 79 return (NULL); 80 /* Must be a character device. */ 81 if (fstat(fd, &sb) || !S_ISCHR(sb.st_mode)) 82 return (NULL); 83 84 if ((db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL)) != NULL) { 85 memset(&bkey, 0, sizeof(bkey)); 86 bkey.type = S_IFCHR; 87 bkey.dev = sb.st_rdev; 88 key.data = &bkey; 89 key.size = sizeof(bkey); 90 if (!(db->get)(db, &key, &data, 0)) { 91 memmove(buf + sizeof(_PATH_DEV) - 1, data.data, 92 data.size); 93 (void)(db->close)(db); 94 return (buf); 95 } 96 (void)(db->close)(db); 97 } 98 return (oldttyname(&sb)); 99 } 100 101 static char * 102 oldttyname(sb) 103 struct stat *sb; 104 { 105 struct dirent *dirp; 106 DIR *dp; 107 struct stat dsb; 108 109 _DIAGASSERT(sb != NULL); 110 111 if ((dp = opendir(_PATH_DEV)) == NULL) 112 return (NULL); 113 114 while ((dirp = readdir(dp)) != NULL) { 115 if (dirp->d_fileno != sb->st_ino) 116 continue; 117 memmove(buf + sizeof(_PATH_DEV) - 1, dirp->d_name, 118 (size_t)(dirp->d_namlen + 1)); 119 if (stat(buf, &dsb) || sb->st_dev != dsb.st_dev || 120 sb->st_ino != dsb.st_ino) 121 continue; 122 (void)closedir(dp); 123 return (buf); 124 } 125 (void)closedir(dp); 126 return (NULL); 127 } 128