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/* $OpenBSD: devname.c,v 1.13 2016/07/06 04:35:12 guenther Exp $ */ |
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/* |
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* Copyright (c) 1989, 1993 |
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* The Regents of the University of California. All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* 3. Neither the name of the University nor the names of its contributors |
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* may be used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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*/ |
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#include <sys/stat.h> |
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#include <sys/types.h> |
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#include <db.h> |
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#include <dirent.h> |
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#include <fcntl.h> |
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#include <limits.h> |
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#include <paths.h> |
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#include <stdbool.h> |
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#include <string.h> |
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#include <stdlib.h> |
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static char * |
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devname_nodb(dev_t dev, mode_t type) |
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{ |
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static char buf[NAME_MAX + 1]; |
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char *name = NULL; |
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struct dirent *dp; |
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struct stat sb; |
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DIR *dirp; |
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if ((dirp = opendir(_PATH_DEV)) == NULL) |
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return (NULL); |
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while ((dp = readdir(dirp)) != NULL) { |
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if (dp->d_type != DT_UNKNOWN && DTTOIF(dp->d_type) != type) |
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continue; |
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if (fstatat(dirfd(dirp), dp->d_name, &sb, AT_SYMLINK_NOFOLLOW) |
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|| sb.st_rdev != dev || (sb.st_mode & S_IFMT) != type) |
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continue; |
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strlcpy(buf, dp->d_name, sizeof(buf)); |
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name = buf; |
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break; |
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} |
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closedir(dirp); |
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return (name); |
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} |
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/* |
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* Keys in dev.db are a mode_t followed by a dev_t. The former is the |
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* type of the file (mode & S_IFMT), the latter is the st_rdev field. |
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* Note that the structure may contain padding. |
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*/ |
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char * |
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devname(dev_t dev, mode_t type) |
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{ |
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static DB *db; |
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static bool failure; |
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struct { |
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mode_t type; |
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dev_t dev; |
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} bkey; |
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DBT data, key; |
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char *name = NULL; |
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if (!db && !failure) { |
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if (!(db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) |
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failure = true; |
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} |
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if (!failure) { |
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/* Be sure to clear any padding that may be found in bkey. */ |
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memset(&bkey, 0, sizeof(bkey)); |
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bkey.dev = dev; |
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bkey.type = type; |
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key.data = &bkey; |
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key.size = sizeof(bkey); |
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if ((db->get)(db, &key, &data, 0) == 0) |
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name = data.data; |
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} else { |
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name = devname_nodb(dev, type); |
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} |
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return (name ? name : "??"); |
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} |
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DEF_WEAK(devname); |