xref: /freebsd/lib/libc/gen/getmntinfo.c (revision dc36d6f9bb1753f3808552f3afd30eda9a7b206a)
1*8a16b7a1SPedro F. Giffuni /*-
2*8a16b7a1SPedro F. Giffuni  * SPDX-License-Identifier: BSD-3-Clause
3*8a16b7a1SPedro F. Giffuni  *
458f0484fSRodney W. Grimes  * Copyright (c) 1989, 1993
558f0484fSRodney W. Grimes  *	The Regents of the University of California.  All rights reserved.
658f0484fSRodney W. Grimes  *
758f0484fSRodney W. Grimes  * Redistribution and use in source and binary forms, with or without
858f0484fSRodney W. Grimes  * modification, are permitted provided that the following conditions
958f0484fSRodney W. Grimes  * are met:
1058f0484fSRodney W. Grimes  * 1. Redistributions of source code must retain the above copyright
1158f0484fSRodney W. Grimes  *    notice, this list of conditions and the following disclaimer.
1258f0484fSRodney W. Grimes  * 2. Redistributions in binary form must reproduce the above copyright
1358f0484fSRodney W. Grimes  *    notice, this list of conditions and the following disclaimer in the
1458f0484fSRodney W. Grimes  *    documentation and/or other materials provided with the distribution.
15fbbd9655SWarner Losh  * 3. Neither the name of the University nor the names of its contributors
1658f0484fSRodney W. Grimes  *    may be used to endorse or promote products derived from this software
1758f0484fSRodney W. Grimes  *    without specific prior written permission.
1858f0484fSRodney W. Grimes  *
1958f0484fSRodney W. Grimes  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
2058f0484fSRodney W. Grimes  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
2158f0484fSRodney W. Grimes  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
2258f0484fSRodney W. Grimes  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
2358f0484fSRodney W. Grimes  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
2458f0484fSRodney W. Grimes  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
2558f0484fSRodney W. Grimes  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
2658f0484fSRodney W. Grimes  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
2758f0484fSRodney W. Grimes  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
2858f0484fSRodney W. Grimes  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
2958f0484fSRodney W. Grimes  * SUCH DAMAGE.
3058f0484fSRodney W. Grimes  */
3158f0484fSRodney W. Grimes 
3258f0484fSRodney W. Grimes #include <sys/param.h>
3358f0484fSRodney W. Grimes #include <sys/ucred.h>
3458f0484fSRodney W. Grimes #include <sys/mount.h>
3558f0484fSRodney W. Grimes #include <stdlib.h>
3658f0484fSRodney W. Grimes 
375a28df2eSConrad Meyer #define	MAX_TRIES	3
385a28df2eSConrad Meyer #define	SCALING_FACTOR	2
395a28df2eSConrad Meyer 
4058f0484fSRodney W. Grimes /*
4158f0484fSRodney W. Grimes  * Return information about mounted filesystems.
4258f0484fSRodney W. Grimes  */
4358f0484fSRodney W. Grimes int
getmntinfo(struct statfs ** mntbufp,int mode)4434ed0c63SJohn Baldwin getmntinfo(struct statfs **mntbufp, int mode)
4558f0484fSRodney W. Grimes {
4658f0484fSRodney W. Grimes 	static struct statfs *mntbuf;
4758f0484fSRodney W. Grimes 	static int mntsize;
4858f0484fSRodney W. Grimes 	static long bufsize;
495a28df2eSConrad Meyer 	unsigned tries = 0;
5058f0484fSRodney W. Grimes 
5158f0484fSRodney W. Grimes 	if (mntsize <= 0 && (mntsize = getfsstat(0, 0, MNT_NOWAIT)) < 0)
5258f0484fSRodney W. Grimes 		return (0);
5334ed0c63SJohn Baldwin 	if (bufsize > 0 && (mntsize = getfsstat(mntbuf, bufsize, mode)) < 0)
5458f0484fSRodney W. Grimes 		return (0);
555a28df2eSConrad Meyer 	while (tries++ < MAX_TRIES && bufsize <= mntsize * sizeof(*mntbuf)) {
565a28df2eSConrad Meyer 		bufsize = (mntsize * SCALING_FACTOR) * sizeof(*mntbuf);
575a28df2eSConrad Meyer 		if ((mntbuf = reallocf(mntbuf, bufsize)) == NULL)
5858f0484fSRodney W. Grimes 			return (0);
5934ed0c63SJohn Baldwin 		if ((mntsize = getfsstat(mntbuf, bufsize, mode)) < 0)
6058f0484fSRodney W. Grimes 			return (0);
6158f0484fSRodney W. Grimes 	}
6258f0484fSRodney W. Grimes 	*mntbufp = mntbuf;
635a28df2eSConrad Meyer 	if (mntsize > (bufsize / sizeof(*mntbuf)))
645a28df2eSConrad Meyer 		return (bufsize / sizeof(*mntbuf));
6558f0484fSRodney W. Grimes 	return (mntsize);
6658f0484fSRodney W. Grimes }
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