1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1989, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__SCCSID("@(#)getmntinfo.c	8.1 (Berkeley) 6/4/93");
34__FBSDID("$FreeBSD$");
35
36#include <sys/param.h>
37#include <sys/ucred.h>
38#include <sys/mount.h>
39#include <stdlib.h>
40
41#define	MAX_TRIES	3
42#define	SCALING_FACTOR	2
43
44/*
45 * Return information about mounted filesystems.
46 */
47int
48getmntinfo(struct statfs **mntbufp, int mode)
49{
50	static struct statfs *mntbuf;
51	static int mntsize;
52	static long bufsize;
53	unsigned tries = 0;
54
55	if (mntsize <= 0 && (mntsize = getfsstat(0, 0, MNT_NOWAIT)) < 0)
56		return (0);
57	if (bufsize > 0 && (mntsize = getfsstat(mntbuf, bufsize, mode)) < 0)
58		return (0);
59	while (tries++ < MAX_TRIES && bufsize <= mntsize * sizeof(*mntbuf)) {
60		bufsize = (mntsize * SCALING_FACTOR) * sizeof(*mntbuf);
61		if ((mntbuf = reallocf(mntbuf, bufsize)) == NULL)
62			return (0);
63		if ((mntsize = getfsstat(mntbuf, bufsize, mode)) < 0)
64			return (0);
65	}
66	*mntbufp = mntbuf;
67	if (mntsize > (bufsize / sizeof(*mntbuf)))
68		return (bufsize / sizeof(*mntbuf));
69	return (mntsize);
70}
71