Libc-166.tar.gz

[apple/libc.git] / gen.subproj / devname.c

/*
 * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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/types.h>
#include <sys/stat.h>

#include <db.h>
#include <dirent.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <stdio.h>
#include <string.h>

static char buf[sizeof(_PATH_DEV) + MAXNAMLEN] = _PATH_DEV;
static char *olddevname __P((dev_t, mode_t));

char *
devname(dev, type)
	dev_t dev;
	mode_t type;
{
	struct {
		mode_t type;
		dev_t dev;
	} bkey;
	static DB *db;
	static int failure;
	DBT data, key;

	if (!db && !failure &&
	    !(db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) {
		failure = 1;
	}
	if (failure)
		return (olddevname(dev, type));

	/*
	 * Keys 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.  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);
	return ((db->get)(db, &key, &data, 0) ? NULL : (char *)data.data);
}

static char *
olddevname(dev, type)
	dev_t dev;
	mode_t type;
{
	register DIR *dp;
	register struct dirent *dirp;
	struct stat sb;

	if ((dp = opendir(_PATH_DEV)) == NULL)
		return (NULL);

	while ( (dirp = readdir(dp)) ) {
		bcopy(dirp->d_name, buf + sizeof(_PATH_DEV) - 1,
		    dirp->d_namlen + 1);
		if (stat(buf, &sb))
			continue;
		if (dev != sb.st_rdev)
			continue;
		if (type != (sb.st_mode & S_IFMT))
			continue;
		(void)closedir(dp);
		return (buf + sizeof(_PATH_DEV) - 1);
	}
	(void)closedir(dp);
	return (NULL);
}