104 lines
3.2 KiB
C
104 lines
3.2 KiB
C
/* $OpenBSD: devname.c,v 1.14 2024/01/22 17:22:58 deraadt 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 = __hash_open(_PATH_DEVDB, O_RDONLY, 0, NULL, 0)))
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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);
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