lib/libc/gen/ttyname.c

   1 /*      $NetBSD: ttyname.c,v 1.23 2006/03/22 00:05:01 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 1.23 2006/03/22 00:05:01 christos Exp $");
  38 #endif
  39 #endif /* LIBC_SCCS and not lint */
  40
  41 #include "namespace.h"
  42 #include <sys/types.h>
  43 #include <sys/param.h>
  44 #include <sys/stat.h>
  45
  46 #include <assert.h>
  47 #include <db.h>
  48 #include <dirent.h>
  49 #include <errno.h>
  50 #include <fcntl.h>
  51 #include <paths.h>
  52 #include <string.h>
  53 #include <termios.h>
  54 #include <unistd.h>
  55 #include <sys/ioctl.h>
  56
  57 #ifdef __weak_alias
  58 __weak_alias(ttyname,_ttyname)
  59 __weak_alias(ttyname_r,_ttyname_r)
  60 #endif
  61
  62 static int oldttyname(const struct stat *, char *, size_t);
  63
  64 int
  65 ttyname_r(int fd, char *buf, size_t len)
  66 {
  67         struct stat sb;
  68         struct termios ttyb;
  69         DB *db;
  70         DBT data, key;
  71         struct {
  72                 mode_t type;
  73                 dev_t dev;
  74         } bkey;
  75         struct ptmget ptm;
  76 #define DEVSZ (sizeof(_PATH_DEV) - 1)
  77
  78         _DIAGASSERT(fd != -1);
  79
  80         if (len <= DEVSZ) {
  81                 return ERANGE;
  82         }
  83
  84         /* If it is a pty, deal with it quickly */
  85         if (ioctl(fd, TIOCPTSNAME, &ptm) != -1) {
  86                 if (strlcpy(buf, ptm.sn, len) >= len) {
  87                         return ERANGE;
  88                 }
  89                 return 0;
  90         }
  91         /* Must be a terminal. */
  92         if (tcgetattr(fd, &ttyb) == -1)
  93                 return errno;
  94
  95         /* Must be a character device. */
  96         if (fstat(fd, &sb))
  97                 return errno;
  98         if (!S_ISCHR(sb.st_mode))
  99                 return ENOTTY;
 100
 101         (void)memcpy(buf, _PATH_DEV, DEVSZ);
 102         if ((db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL)) != NULL) {
 103                 (void)memset(&bkey, 0, sizeof(bkey));
 104                 bkey.type = S_IFCHR;
 105                 bkey.dev = sb.st_rdev;
 106                 key.data = &bkey;
 107                 key.size = sizeof(bkey);
 108                 if (!(db->get)(db, &key, &data, 0)) {
 109                         if (len - DEVSZ <= data.size) {
 110                                 return ERANGE;
 111                         }
 112                         (void)memcpy(buf + DEVSZ, data.data, data.size);
 113                         (void)(db->close)(db);
 114                         return 0;
 115                 }
 116                 (void)(db->close)(db);
 117         }
 118         if (oldttyname(&sb, buf, len) == -1)
 119                 return errno;
 120         return 0;
 121 }
 122
 123 static int
 124 oldttyname(const struct stat *sb, char *buf, size_t len)
 125 {
 126         struct dirent *dirp;
 127         DIR *dp;
 128         struct stat dsb;
 129         size_t dlen;
 130
 131         _DIAGASSERT(sb != NULL);
 132
 133         if ((dp = opendir(_PATH_DEV)) == NULL)
 134                 return -1;
 135
 136         while ((dirp = readdir(dp)) != NULL) {
 137                 if (dirp->d_fileno != sb->st_ino)
 138                         continue;
 139                 dlen = dirp->d_namlen + 1;
 140                 if (len - DEVSZ <= dlen) {
 141                         /*
 142                          * XXX: we return an error if *any* entry does not
 143                          * fit
 144                          */
 145                         errno = ERANGE;
 146                         (void)closedir(dp);
 147                         return -1;
 148                 }
 149                 (void)memcpy(buf + DEVSZ, dirp->d_name, dlen);
 150                 if (stat(buf, &dsb) || sb->st_dev != dsb.st_dev ||
 151                     sb->st_ino != dsb.st_ino)
 152                         continue;
 153                 (void)closedir(dp);
 154                 return 0;
 155         }
 156         (void)closedir(dp);
 157         /*
 158          * XXX: Documented by TOG to return EBADF or ENOTTY only; neither are
 159          * applicable here.
 160          */
 161         errno = ENOENT;
 162         return -1;
 163 }
 164
 165 char *
 166 ttyname(int fd)
 167 {
 168         static char buf[MAXPATHLEN];
 169         int rv;
 170
 171         rv = ttyname_r(fd, buf, sizeof(buf));
 172         if (rv != 0) {
 173                 errno = rv;
 174                 return NULL;
 175         }
 176         return buf;
 177 }