gen/FreeBSD/ttyname.c

   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)
  35 static 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: src/lib/libc/gen/ttyname.c,v 1.12 2002/02/01 01:32:19 obrien Exp $");
  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
  56 static char buf[sizeof(_PATH_DEV) + MAXNAMLEN] = _PATH_DEV;
  57 static char *oldttyname(int, struct stat *);
  58 static char *ttyname_threaded(int fd);
  59 static char *ttyname_unthreaded(int fd);
  60
  61 static pthread_mutex_t  ttyname_lock = PTHREAD_MUTEX_INITIALIZER;
  62 static pthread_key_t    ttyname_key;
  63 static int              ttyname_init = 0;
  64
  65 char *
  66 ttyname(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
  77 char *
  78 ttyname_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
 118 static char *
 119 ttyname_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
 149 static char *
 150 ttyname_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
 185 static char *
 186 oldttyname(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 }