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/* $NetBSD: devname.c,v 1.22 2012/06/03 21:42:46 joerg Exp $ */
/*-
* Copyright (c) 2012 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Simon Burge.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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/cdefs.h>
__RCSID("$NetBSD: devname.c,v 1.22 2012/06/03 21:42:46 joerg Exp $");
#include "namespace.h"
#include "reentrant.h"
#include <sys/stat.h>
#include <cdbr.h>
#include <errno.h>
#include <fts.h>
#include <limits.h>
#include <paths.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#ifdef __minix
#include <minix/dmap.h> /* for UNIX98_MINOR */
#endif /* __minix */
#ifdef __weak_alias
__weak_alias(devname_r,_devname_r)
#endif
static once_t db_opened = ONCE_INITIALIZER;
static struct cdbr *db;
static devmajor_t pts;
static void
devname_dbopen(void)
{
db = cdbr_open(_PATH_DEVCDB, CDBR_DEFAULT);
pts = getdevmajor("pts", S_IFCHR);
}
__CTASSERT(sizeof(dev_t) == 8);
static int
devname_dblookup(dev_t dev, mode_t type, char *path, size_t len)
{
const void *data;
size_t datalen;
uint8_t key[10];
le64enc(key, dev);
le16enc(key + 8, type);
if (cdbr_find(db, key, sizeof(key), &data, &datalen) != 0)
return ENOENT;
if (datalen <= sizeof(key))
return ENOENT;
if (memcmp(key, data, sizeof(key)) != 0)
return ENOENT;
data = (const char *)data + sizeof(key);
datalen -= sizeof(key);
if (memchr(data, '\0', datalen) != (const char *)data + datalen - 1)
return ENOENT;
if (datalen > len)
return ERANGE;
memcpy(path, data, datalen);
return 0;
}
static int
devname_ptslookup(dev_t dev, mode_t type, char *path, size_t len)
{
int rv;
if (type != S_IFCHR || pts == NODEVMAJOR || major(dev) != pts)
return ENOENT;
#ifdef __minix
/*
* MINIX3 does not use an identity mapping for /dev/pts, because the
* same major number is also used for PTY masters and legacy PTYs.
*/
if (minor(dev) < UNIX98_MINOR || !(minor(dev) & 1))
return ENOENT;
#endif /* __minix */
rv = snprintf(path, len, "%s%d", _PATH_DEV_PTS + sizeof(_PATH_DEV) - 1,
#ifndef __minix
minor(dev));
#else /* __minix */
(minor(dev) - UNIX98_MINOR) >> 1);
#endif /* __minix */
if (rv < 0 || (size_t)rv >= len)
return ERANGE;
return 0;
}
static int
devname_fts(dev_t dev, mode_t type, char *path, size_t len)
{
FTS *ftsp;
FTSENT *fe;
static const char path_dev[] = _PATH_DEV;
static char * const dirs[2] = { __UNCONST(path_dev), NULL };
const size_t len_dev = strlen(path_dev);
int rv;
if ((ftsp = fts_open(dirs, FTS_NOCHDIR | FTS_PHYSICAL, NULL)) == NULL)
return ENOENT;
rv = ENOENT;
while ((fe = fts_read(ftsp)) != NULL) {
if (fe->fts_info != FTS_DEFAULT)
continue;
if (fe->fts_statp->st_rdev != dev)
continue;
if ((type & S_IFMT) != (fe->fts_statp->st_mode & S_IFMT))
continue;
if (strncmp(fe->fts_path, path_dev, len_dev))
continue;
if (strlcpy(path, fe->fts_path + len_dev, len) < len) {
rv = 0;
break;
}
}
fts_close(ftsp);
return rv;
}
int
devname_r(dev_t dev, mode_t type, char *path, size_t len)
{
int rv;
thr_once(&db_opened, devname_dbopen);
if (db != NULL) {
rv = devname_dblookup(dev, type, path, len);
if (rv == 0 || rv == ERANGE)
return rv;
}
rv = devname_ptslookup(dev, type, path, len);
if (rv == 0 || rv == ERANGE)
return rv;
if (db != NULL)
return ENOENT;
rv = devname_fts(dev, type, path, len);
return rv;
}
char *
devname(dev_t dev, mode_t type)
{
static char path[PATH_MAX];
return devname_r(dev, type, path, sizeof(path)) == 0 ? path : NULL;
}
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