1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1995
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("@(#)kvm_getvfsbyname.c	8.1 (Berkeley) 4/3/95");
34__FBSDID("$FreeBSD$");
35
36#include <sys/param.h>
37#include <sys/mount.h>
38#include <sys/sysctl.h>
39#include <errno.h>
40#include <stdbool.h>
41#include <stdlib.h>
42#include <string.h>
43
44/*
45 * fusefs(5) file systems may have a "subtype" which gets appended to
46 * statfs(2)'s f_fstypename field on a per-mount basis.  Allow getvfsbyname to
47 * match either the full "fusefs.foobar" or the more general "fusefs".
48 */
49static bool
50are_fusefs(const char *fsname, const char *vfc_name)
51{
52	const static char fusefs[] = "fusefs";
53	const static char fusefs_dot[] = "fusefs.";
54
55	return (strncmp(fsname, fusefs_dot, sizeof(fusefs_dot) - 1) == 0 &&
56	    strcmp(fusefs, vfc_name) == 0);
57}
58
59/*
60 * Given a filesystem name, determine if it is resident in the kernel,
61 * and if it is resident, return its xvfsconf structure.
62 */
63int
64getvfsbyname(const char *fsname, struct xvfsconf *vfcp)
65{
66	struct xvfsconf *xvfsp;
67	size_t buflen;
68	int cnt, i;
69
70	if (sysctlbyname("vfs.conflist", NULL, &buflen, NULL, 0) < 0)
71		return (-1);
72	xvfsp = malloc(buflen);
73	if (xvfsp == NULL)
74		return (-1);
75	if (sysctlbyname("vfs.conflist", xvfsp, &buflen, NULL, 0) < 0) {
76		free(xvfsp);
77		return (-1);
78	}
79	cnt = buflen / sizeof(struct xvfsconf);
80	for (i = 0; i < cnt; i++) {
81		if (strcmp(fsname, xvfsp[i].vfc_name) == 0 ||
82		    are_fusefs(fsname, xvfsp[i].vfc_name)) {
83			memcpy(vfcp, xvfsp + i, sizeof(struct xvfsconf));
84			free(xvfsp);
85			return (0);
86		}
87	}
88	free(xvfsp);
89	errno = ENOENT;
90	return (-1);
91}
92