ttyname.c revision 90045
1/* 2 * Copyright (c) 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#if defined(LIBC_SCCS) && !defined(lint) 35static char sccsid[] = "@(#)ttyname.c 8.2 (Berkeley) 1/27/94"; 36#endif /* LIBC_SCCS and not lint */ 37#include <sys/cdefs.h> 38__FBSDID("$FreeBSD: head/lib/libc/gen/ttyname.c 90045 2002-02-01 01:32:19Z obrien $"); 39 40#include "namespace.h" 41#include <sys/types.h> 42#include <sys/stat.h> 43#include <fcntl.h> 44#include <dirent.h> 45#include <stdlib.h> 46#include <termios.h> 47#include <unistd.h> 48#include <string.h> 49#include <paths.h> 50#include <pthread.h> 51#include "un-namespace.h" 52 53#include <db.h> 54#include "libc_private.h" 55 56static char buf[sizeof(_PATH_DEV) + MAXNAMLEN] = _PATH_DEV; 57static char *oldttyname(int, struct stat *); 58static char *ttyname_threaded(int fd); 59static char *ttyname_unthreaded(int fd); 60 61static pthread_mutex_t ttyname_lock = PTHREAD_MUTEX_INITIALIZER; 62static pthread_key_t ttyname_key; 63static int ttyname_init = 0; 64 65char * 66ttyname(int fd) 67{ 68 char *ret; 69 70 if (__isthreaded == 0) 71 ret = ttyname_unthreaded(fd); 72 else 73 ret = ttyname_threaded(fd); 74 return (ret); 75} 76 77char * 78ttyname_r(int fd, char *buf, size_t len) 79{ 80 struct dirent *dirp; 81 DIR *dp; 82 struct stat dsb; 83 struct stat sb; 84 char *rval; 85 int minlen; 86 87 rval = NULL; 88 89 /* Must be a terminal. */ 90 if (!isatty(fd)) 91 return (rval); 92 /* Must be a character device. */ 93 if (_fstat(fd, &sb) || !S_ISCHR(sb.st_mode)) 94 return (rval); 95 /* Must have enough room */ 96 if (len <= sizeof(_PATH_DEV)) 97 return (rval); 98 99 if ((dp = opendir(_PATH_DEV)) != NULL) { 100 memcpy(buf, _PATH_DEV, sizeof(_PATH_DEV)); 101 for (rval = NULL; (dirp = readdir(dp)) != NULL;) { 102 if (dirp->d_fileno != sb.st_ino) 103 continue; 104 minlen = (len - (sizeof(_PATH_DEV) - 1)) < (dirp->d_namlen + 1) ? 105 (len - (sizeof(_PATH_DEV) - 1)) : (dirp->d_namlen + 1); 106 memcpy(buf + sizeof(_PATH_DEV) - 1, dirp->d_name, minlen); 107 if (stat(buf, &dsb) || sb.st_dev != dsb.st_dev || 108 sb.st_ino != dsb.st_ino) 109 continue; 110 rval = buf; 111 break; 112 } 113 (void) closedir(dp); 114 } 115 return (rval); 116} 117 118static char * 119ttyname_threaded(int fd) 120{ 121 char *buf; 122 123 if (ttyname_init == 0) { 124 _pthread_mutex_lock(&ttyname_lock); 125 if (ttyname_init == 0) { 126 if (_pthread_key_create(&ttyname_key, free)) { 127 _pthread_mutex_unlock(&ttyname_lock); 128 return (NULL); 129 } 130 ttyname_init = 1; 131 } 132 _pthread_mutex_unlock(&ttyname_lock); 133 } 134 135 /* Must have thread specific data field to put data */ 136 if ((buf = _pthread_getspecific(ttyname_key)) == NULL) { 137 if ((buf = malloc(sizeof(_PATH_DEV) + MAXNAMLEN)) != NULL) { 138 if (_pthread_setspecific(ttyname_key, buf) != 0) { 139 free(buf); 140 return (NULL); 141 } 142 } else { 143 return (NULL); 144 } 145 } 146 return (ttyname_r(fd, buf, sizeof(_PATH_DEV) + MAXNAMLEN)); 147} 148 149static char * 150ttyname_unthreaded(int fd) 151{ 152 struct stat sb; 153 struct termios ttyb; 154 DB *db; 155 DBT data, key; 156 struct { 157 mode_t type; 158 dev_t dev; 159 } bkey; 160 161 /* Must be a terminal. */ 162 if (tcgetattr(fd, &ttyb) < 0) 163 return (NULL); 164 /* Must be a character device. */ 165 if (_fstat(fd, &sb) || !S_ISCHR(sb.st_mode)) 166 return (NULL); 167 168 if ( (db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL)) ) { 169 memset(&bkey, 0, sizeof(bkey)); 170 bkey.type = S_IFCHR; 171 bkey.dev = sb.st_rdev; 172 key.data = &bkey; 173 key.size = sizeof(bkey); 174 if (!(db->get)(db, &key, &data, 0)) { 175 bcopy(data.data, 176 buf + sizeof(_PATH_DEV) - 1, data.size); 177 (void)(db->close)(db); 178 return (buf); 179 } 180 (void)(db->close)(db); 181 } 182 return (oldttyname(fd, &sb)); 183} 184 185static char * 186oldttyname(int fd, struct stat *sb) 187{ 188 struct dirent *dirp; 189 struct stat dsb; 190 DIR *dp; 191 192 if ((dp = opendir(_PATH_DEV)) == NULL) 193 return (NULL); 194 195 while ( (dirp = readdir(dp)) ) { 196 if (dirp->d_fileno != sb->st_ino) 197 continue; 198 bcopy(dirp->d_name, buf + sizeof(_PATH_DEV) - 1, 199 dirp->d_namlen + 1); 200 if (stat(buf, &dsb) || sb->st_dev != dsb.st_dev || 201 sb->st_ino != dsb.st_ino) 202 continue; 203 (void)closedir(dp); 204 return (buf); 205 } 206 (void)closedir(dp); 207 return (NULL); 208} 209