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/param.h>
33 #include <sys/ucred.h>
34 #include <sys/mount.h>
35 #include <stdlib.h>
36
37 #define MAX_TRIES 3
38 #define SCALING_FACTOR 2
39
40 /*
41 * Return information about mounted filesystems.
42 */
43 int
getmntinfo(struct statfs ** mntbufp,int mode)44 getmntinfo(struct statfs **mntbufp, int mode)
45 {
46 static struct statfs *mntbuf;
47 static int mntsize;
48 static long bufsize;
49 unsigned tries = 0;
50
51 if (mntsize <= 0 && (mntsize = getfsstat(0, 0, MNT_NOWAIT)) < 0)
52 return (0);
53 if (bufsize > 0 && (mntsize = getfsstat(mntbuf, bufsize, mode)) < 0)
54 return (0);
55 while (tries++ < MAX_TRIES && bufsize <= mntsize * sizeof(*mntbuf)) {
56 bufsize = (mntsize * SCALING_FACTOR) * sizeof(*mntbuf);
57 if ((mntbuf = reallocf(mntbuf, bufsize)) == NULL)
58 return (0);
59 if ((mntsize = getfsstat(mntbuf, bufsize, mode)) < 0)
60 return (0);
61 }
62 *mntbufp = mntbuf;
63 if (mntsize > (bufsize / sizeof(*mntbuf)))
64 return (bufsize / sizeof(*mntbuf));
65 return (mntsize);
66 }
67