lib/libc/gen/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  * $FreeBSD: src/lib/libc/gen/ttyname.c,v 1.10.6.2 2002/10/15 19:46:46 fjoe Exp $
  34  * $DragonFly: src/lib/libc/gen/ttyname.c,v 1.14 2005/11/19 22:32:53 swildner Exp $
  35  *
  36  * @(#)ttyname.c        8.2 (Berkeley) 1/27/94
  37  */
  38
  39 #include "namespace.h"
  40 #include <sys/types.h>
  41 #include <sys/stat.h>
  42 #include <fcntl.h>
  43 #include <dirent.h>
  44 #include <limits.h>
  45 #include <stdlib.h>
  46 #include <termios.h>
  47 #include <unistd.h>
  48 #include <string.h>
  49 #include <paths.h>
  50
  51 #include <pthread.h>
  52 #include "un-namespace.h"
  53
  54 #include <db.h>
  55 #include "libc_private.h"
  56
  57 static char static_buf[TTY_PATH_MAX] = _PATH_DEV;
  58 static char *oldttyname(int, struct stat *);
  59 static char *ttyname_threaded(int fd);
  60 static char *ttyname_unthreaded(int fd);
  61 extern int  __sys_fstat(int, struct stat *);
  62
  63 static pthread_mutex_t  ttyname_lock = PTHREAD_MUTEX_INITIALIZER;
  64 static pthread_key_t    ttyname_key;
  65 static int              ttyname_init = 0;
  66
  67 char *
  68 ttyname(int fd)
  69 {
  70         char           *ret;
  71
  72         if (__isthreaded == 0)
  73                 ret = ttyname_unthreaded(fd);
  74         else
  75                 ret = ttyname_threaded(fd);
  76         return (ret);
  77 }
  78
  79 char *
  80 ttyname_r(int fd, char *buf, size_t len)
  81 {
  82         struct dirent *dirp;
  83         DIR   *dp;
  84         struct stat     dsb;
  85         struct stat     sb;
  86         char           *rval;
  87         int             minlen;
  88
  89         rval = NULL;
  90
  91         /* Must be a terminal. */
  92         if (!isatty(fd))
  93                 return (rval);
  94         /* Must be a character device. */
  95         if (__sys_fstat(fd, &sb) || !S_ISCHR(sb.st_mode))
  96                 return (rval);
  97         /* Must have enough room */
  98         if (len <= sizeof(_PATH_DEV))
  99                 return (rval);
 100
 101         if ((dp = opendir(_PATH_DEV)) != NULL) {
 102                 memcpy(buf, _PATH_DEV, sizeof(_PATH_DEV));
 103                 for (rval = NULL; (dirp = readdir(dp)) != NULL;) {
 104                         if (dirp->d_ino != sb.st_ino)
 105                                 continue;
 106                         minlen = (len - (sizeof(_PATH_DEV) - 1)) < (dirp->d_namlen + 1) ?
 107                                 (len - (sizeof(_PATH_DEV) - 1)) : (dirp->d_namlen + 1);
 108                         memcpy(buf + sizeof(_PATH_DEV) - 1, dirp->d_name, minlen);
 109                         if (stat(buf, &dsb) || sb.st_dev != dsb.st_dev ||
 110                             sb.st_ino != dsb.st_ino)
 111                                 continue;
 112                         rval = buf;
 113                         break;
 114                 }
 115                 closedir(dp);
 116         }
 117         return (rval);
 118 }
 119
 120 char *
 121 ttyname_threaded(int fd)
 122 {
 123         char    *buf;
 124
 125         if (ttyname_init == 0) {
 126                 _pthread_mutex_lock(&ttyname_lock);
 127                 if (ttyname_init == 0) {
 128                         if (_pthread_key_create(&ttyname_key, free)) {
 129                                 _pthread_mutex_unlock(&ttyname_lock);
 130                                 return (NULL);
 131                         }
 132                         ttyname_init = 1;
 133                 }
 134                 _pthread_mutex_unlock(&ttyname_lock);
 135         }
 136
 137         /* Must have thread specific data field to put data */
 138         if ((buf = _pthread_getspecific(ttyname_key)) == NULL) {
 139                 if ((buf = malloc(TTY_PATH_MAX)) != NULL) {
 140                         if (_pthread_setspecific(ttyname_key, buf) != 0) {
 141                                 free(buf);
 142                                 return (NULL);
 143                         }
 144                 } else {
 145                         return (NULL);
 146                 }
 147         }
 148         return (ttyname_r(fd, buf, TTY_PATH_MAX));
 149 }
 150
 151 static char *
 152 ttyname_unthreaded(int fd)
 153 {
 154         struct stat sb;
 155         struct termios ttyb;
 156         DB *db;
 157         DBT data, key;
 158         struct {
 159                 mode_t type;
 160                 dev_t dev;
 161         } bkey;
 162
 163         /* Must be a terminal. */
 164         if (tcgetattr(fd, &ttyb) < 0)
 165                 return (NULL);
 166         /* Must be a character device. */
 167         if (_fstat(fd, &sb) || !S_ISCHR(sb.st_mode))
 168                 return (NULL);
 169
 170         if ( (db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL)) ) {
 171                 memset(&bkey, 0, sizeof(bkey));
 172                 bkey.type = S_IFCHR;
 173                 bkey.dev = sb.st_rdev;
 174                 key.data = &bkey;
 175                 key.size = sizeof(bkey);
 176                 if (!(db->get)(db, &key, &data, 0) &&
 177                     (sizeof(_PATH_DEV) + data.size - 1 < sizeof(static_buf))) {
 178                         bcopy(data.data,
 179                             static_buf + sizeof(_PATH_DEV) - 1, data.size);
 180                         (db->close)(db);
 181                         return (static_buf);
 182                 }
 183                 (db->close)(db);
 184         }
 185         return (oldttyname(fd, &sb));
 186 }
 187
 188 static char *
 189 oldttyname(int fd __unused, struct stat *sb)
 190 {
 191         struct dirent *dirp;
 192         DIR *dp;
 193         struct stat dsb;
 194
 195         if ((dp = opendir(_PATH_DEV)) == NULL)
 196                 return (NULL);
 197
 198         while ( (dirp = readdir(dp)) ) {
 199                 if (dirp->d_ino != sb->st_ino)
 200                         continue;
 201                 if (sizeof(_PATH_DEV) + dirp->d_namlen >= sizeof(static_buf))
 202                         continue;
 203                 bcopy(dirp->d_name, static_buf + sizeof(_PATH_DEV) - 1,
 204                     dirp->d_namlen + 1);
 205                 if (stat(static_buf, &dsb) || sb->st_dev != dsb.st_dev ||
 206                     sb->st_ino != dsb.st_ino)
 207                         continue;
 208                 closedir(dp);
 209                 return (static_buf);
 210         }
 211         closedir(dp);
 212         return (NULL);
 213 }