1 /* $OpenBSD: ttyname.c,v 1.18 2016/06/27 16:52:30 espie Exp $ */ 2 /* 3 * Copyright (c) 1988, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Neither the name of the University nor the names of its contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <sys/types.h> 32 #include <sys/stat.h> 33 #include <fcntl.h> 34 #include <dirent.h> 35 #include <db.h> 36 #include <string.h> 37 #include <unistd.h> 38 #include <paths.h> 39 #include <limits.h> 40 #include <errno.h> 41 #include "thread_private.h" 42 43 static char buf[TTY_NAME_MAX]; 44 static int oldttyname(struct stat *, char *, size_t); 45 46 char * 47 ttyname(int fd) 48 { 49 _THREAD_PRIVATE_KEY(ttyname); 50 char *bufp = (char *) _THREAD_PRIVATE(ttyname, buf, NULL); 51 int err; 52 53 if (bufp == NULL) 54 return NULL; 55 56 err = ttyname_r(fd, bufp, sizeof buf); 57 if (err) { 58 errno = err; 59 return NULL; 60 } 61 62 return bufp; 63 } 64 DEF_WEAK(ttyname); 65 66 int 67 ttyname_r(int fd, char *buf, size_t len) 68 { 69 struct stat sb; 70 DB *db; 71 DBT data, key; 72 struct { 73 mode_t type; 74 dev_t dev; 75 } bkey; 76 77 /* Must be a terminal. */ 78 if (!isatty(fd)) 79 return (errno); 80 /* Must be a character device. */ 81 if (fstat(fd, &sb)) 82 return (errno); 83 if (!S_ISCHR(sb.st_mode)) 84 return (ENOTTY); 85 if (len < sizeof(_PATH_DEV)) 86 return (ERANGE); 87 88 memcpy(buf, _PATH_DEV, sizeof(_PATH_DEV)); 89 90 if ((db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) { 91 memset(&bkey, 0, sizeof(bkey)); 92 bkey.type = S_IFCHR; 93 bkey.dev = sb.st_rdev; 94 key.data = &bkey; 95 key.size = sizeof(bkey); 96 if (!(db->get)(db, &key, &data, 0)) { 97 if (data.size > len - (sizeof(_PATH_DEV) - 1)) { 98 (void)(db->close)(db); 99 return (ERANGE); 100 } 101 memcpy(buf + sizeof(_PATH_DEV) - 1, data.data, 102 data.size); 103 (void)(db->close)(db); 104 return (0); 105 } 106 (void)(db->close)(db); 107 } 108 return (oldttyname(&sb, buf, len)); 109 } 110 DEF_WEAK(ttyname_r); 111 112 static int 113 oldttyname(struct stat *sb, char *buf, size_t len) 114 { 115 struct dirent *dirp; 116 DIR *dp; 117 struct stat dsb; 118 119 if ((dp = opendir(_PATH_DEV)) == NULL) 120 return (errno); 121 122 while ((dirp = readdir(dp))) { 123 if (dirp->d_type != DT_CHR && dirp->d_type != DT_UNKNOWN) 124 continue; 125 if (fstatat(dirfd(dp), dirp->d_name, &dsb, AT_SYMLINK_NOFOLLOW) 126 || !S_ISCHR(dsb.st_mode) || sb->st_rdev != dsb.st_rdev) 127 continue; 128 (void)closedir(dp); 129 if (dirp->d_namlen > len - sizeof(_PATH_DEV)) 130 return (ERANGE); 131 memcpy(buf + sizeof(_PATH_DEV) - 1, dirp->d_name, 132 dirp->d_namlen + 1); 133 return (0); 134 } 135 (void)closedir(dp); 136 return (ENOTTY); 137 } 138