1 /* $NetBSD: devname.c,v 1.22 2012/06/03 21:42:46 joerg Exp $ */ 2 3 /*- 4 * Copyright (c) 2012 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Simon Burge. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __RCSID("$NetBSD: devname.c,v 1.22 2012/06/03 21:42:46 joerg Exp $"); 34 35 #include "namespace.h" 36 #include "reentrant.h" 37 #include <sys/stat.h> 38 39 #include <cdbr.h> 40 #include <errno.h> 41 #include <fts.h> 42 #include <limits.h> 43 #include <paths.h> 44 #include <stdio.h> 45 #include <string.h> 46 #include <stdlib.h> 47 48 #ifdef __weak_alias 49 __weak_alias(devname_r,_devname_r) 50 #endif 51 52 #if !defined(__minix) 53 static once_t db_opened = ONCE_INITIALIZER; 54 static struct cdbr *db; 55 static devmajor_t pts; 56 57 static void 58 devname_dbopen(void) 59 { 60 db = cdbr_open(_PATH_DEVCDB, CDBR_DEFAULT); 61 pts = getdevmajor("pts", S_IFCHR); 62 } 63 64 __CTASSERT(sizeof(dev_t) == 8); 65 66 static int 67 devname_dblookup(dev_t dev, mode_t type, char *path, size_t len) 68 { 69 const void *data; 70 size_t datalen; 71 uint8_t key[10]; 72 73 le64enc(key, dev); 74 le16enc(key + 8, type); 75 if (cdbr_find(db, key, sizeof(key), &data, &datalen) != 0) 76 return ENOENT; 77 if (datalen <= sizeof(key)) 78 return ENOENT; 79 if (memcmp(key, data, sizeof(key)) != 0) 80 return ENOENT; 81 data = (const char *)data + sizeof(key); 82 datalen -= sizeof(key); 83 if (memchr(data, '\0', datalen) != (const char *)data + datalen - 1) 84 return ENOENT; 85 if (datalen > len) 86 return ERANGE; 87 memcpy(path, data, datalen); 88 return 0; 89 } 90 91 static int 92 devname_ptslookup(dev_t dev, mode_t type, char *path, size_t len) 93 { 94 int rv; 95 96 if (type != S_IFCHR || pts == NODEVMAJOR || major(dev) != pts) 97 return ENOENT; 98 99 rv = snprintf(path, len, "%s%d", _PATH_DEV_PTS + sizeof(_PATH_DEV) - 1, 100 minor(dev)); 101 if (rv < 0 || (size_t)rv >= len) 102 return ERANGE; 103 return 0; 104 } 105 #endif /* !defined(__minix) */ 106 107 static int 108 devname_fts(dev_t dev, mode_t type, char *path, size_t len) 109 { 110 FTS *ftsp; 111 FTSENT *fe; 112 static const char path_dev[] = _PATH_DEV; 113 static char * const dirs[2] = { __UNCONST(path_dev), NULL }; 114 const size_t len_dev = strlen(path_dev); 115 int rv; 116 117 if ((ftsp = fts_open(dirs, FTS_NOCHDIR | FTS_PHYSICAL, NULL)) == NULL) 118 return ENOENT; 119 120 rv = ENOENT; 121 while ((fe = fts_read(ftsp)) != NULL) { 122 if (fe->fts_info != FTS_DEFAULT) 123 continue; 124 if (fe->fts_statp->st_rdev != dev) 125 continue; 126 if ((type & S_IFMT) != (fe->fts_statp->st_mode & S_IFMT)) 127 continue; 128 if (strncmp(fe->fts_path, path_dev, len_dev)) 129 continue; 130 if (strlcpy(path, fe->fts_path + len_dev, len) < len) { 131 rv = 0; 132 break; 133 } 134 } 135 136 fts_close(ftsp); 137 return rv; 138 } 139 140 int 141 devname_r(dev_t dev, mode_t type, char *path, size_t len) 142 { 143 int rv; 144 145 #if !defined(__minix) 146 thr_once(&db_opened, devname_dbopen); 147 148 if (db != NULL) { 149 rv = devname_dblookup(dev, type, path, len); 150 if (rv == 0 || rv == ERANGE) 151 return rv; 152 } 153 154 rv = devname_ptslookup(dev, type, path, len); 155 if (rv == 0 || rv == ERANGE) 156 return rv; 157 158 if (db != NULL) 159 return ENOENT; 160 #endif /* !defined(__minix) */ 161 rv = devname_fts(dev, type, path, len); 162 return rv; 163 } 164 165 char * 166 devname(dev_t dev, mode_t type) 167 { 168 static char path[PATH_MAX]; 169 170 return devname_r(dev, type, path, sizeof(path)) == 0 ? path : NULL; 171 } 172