1 /* $NetBSD: ttyname.c,v 1.20 2004/11/11 00:00:15 christos 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 1.20 2004/11/11 00:00:15 christos 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 #include <sys/ioctl.h> 55 56 #ifdef __weak_alias 57 __weak_alias(ttyname,_ttyname) 58 #endif 59 60 static char buf[sizeof(_PATH_DEV) + MAXNAMLEN] = _PATH_DEV; 61 static struct ptmget ptm; 62 static char *oldttyname __P((struct stat *)); 63 64 char * 65 ttyname(fd) 66 int fd; 67 { 68 struct stat sb; 69 struct termios ttyb; 70 DB *db; 71 DBT data, key; 72 struct { 73 mode_t type; 74 dev_t dev; 75 } bkey; 76 77 _DIAGASSERT(fd != -1); 78 79 /* If it is a pty, deal with it quickly */ 80 if (ioctl(fd, TIOCPTSNAME, &ptm) != -1) 81 return ptm.sn; 82 83 /* Must be a terminal. */ 84 if (tcgetattr(fd, &ttyb) < 0) 85 return (NULL); 86 /* Must be a character device. */ 87 if (fstat(fd, &sb) || !S_ISCHR(sb.st_mode)) 88 return (NULL); 89 90 if ((db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL)) != NULL) { 91 memset(&bkey, 0, sizeof(bkey)); 92 bkey.type = S_IFCHR; 93 bkey.dev = sb.st_rdev; 94 key.data = &bkey; 95 key.size = sizeof(bkey); 96 if (!(db->get)(db, &key, &data, 0)) { 97 memmove(buf + sizeof(_PATH_DEV) - 1, data.data, 98 data.size); 99 (void)(db->close)(db); 100 return (buf); 101 } 102 (void)(db->close)(db); 103 } 104 return (oldttyname(&sb)); 105 } 106 107 static char * 108 oldttyname(sb) 109 struct stat *sb; 110 { 111 struct dirent *dirp; 112 DIR *dp; 113 struct stat dsb; 114 115 _DIAGASSERT(sb != NULL); 116 117 if ((dp = opendir(_PATH_DEV)) == NULL) 118 return (NULL); 119 120 while ((dirp = readdir(dp)) != NULL) { 121 if (dirp->d_fileno != sb->st_ino) 122 continue; 123 memmove(buf + sizeof(_PATH_DEV) - 1, dirp->d_name, 124 (size_t)(dirp->d_namlen + 1)); 125 if (stat(buf, &dsb) || sb->st_dev != dsb.st_dev || 126 sb->st_ino != dsb.st_ino) 127 continue; 128 (void)closedir(dp); 129 return (buf); 130 } 131 (void)closedir(dp); 132 return (NULL); 133 } 134