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ttyname.c revision 1.24 
      1 /*	$NetBSD: ttyname.c,v 1.24 2008/06/25 11:47:29 ad 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 1.24 2008/06/25 11:47:29 ad 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 }
    178