xref: /freebsd/lib/libc/gen/getvfsbyname.c (revision 55141f2c8991b2a6adbf30bb0fe3e6cbc303f06d)
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 #include <sys/param.h>
35 #include <sys/mount.h>
36 #include <sys/sysctl.h>
37 #include <errno.h>
38 #include <stdbool.h>
39 #include <stdlib.h>
40 #include <string.h>
41 
42 /*
43  * fusefs(5) file systems may have a "subtype" which gets appended to
44  * statfs(2)'s f_fstypename field on a per-mount basis.  Allow getvfsbyname to
45  * match either the full "fusefs.foobar" or the more general "fusefs".
46  */
47 static bool
48 are_fusefs(const char *fsname, const char *vfc_name)
49 {
50 	const static char fusefs[] = "fusefs";
51 	const static char fusefs_dot[] = "fusefs.";
52 
53 	return (strncmp(fsname, fusefs_dot, sizeof(fusefs_dot) - 1) == 0 &&
54 	    strcmp(fusefs, vfc_name) == 0);
55 }
56 
57 /*
58  * Given a filesystem name, determine if it is resident in the kernel,
59  * and if it is resident, return its xvfsconf structure.
60  */
61 int
62 getvfsbyname(const char *fsname, struct xvfsconf *vfcp)
63 {
64 	struct xvfsconf *xvfsp;
65 	size_t buflen;
66 	int cnt, i;
67 
68 	if (sysctlbyname("vfs.conflist", NULL, &buflen, NULL, 0) < 0)
69 		return (-1);
70 	xvfsp = malloc(buflen);
71 	if (xvfsp == NULL)
72 		return (-1);
73 	if (sysctlbyname("vfs.conflist", xvfsp, &buflen, NULL, 0) < 0) {
74 		free(xvfsp);
75 		return (-1);
76 	}
77 	cnt = buflen / sizeof(struct xvfsconf);
78 	for (i = 0; i < cnt; i++) {
79 		if (strcmp(fsname, xvfsp[i].vfc_name) == 0 ||
80 		    are_fusefs(fsname, xvfsp[i].vfc_name)) {
81 			memcpy(vfcp, xvfsp + i, sizeof(struct xvfsconf));
82 			free(xvfsp);
83 			return (0);
84 		}
85 	}
86 	free(xvfsp);
87 	errno = ENOENT;
88 	return (-1);
89 }
90