xref: /freebsd/lib/libc/gen/getvfsbyname.c (revision 7ef62cebc2f965b0f640263e179276928885e33d)
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  */
49 static bool
50 are_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  */
63 int
64 getvfsbyname(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