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