xref: /freebsd/sys/contrib/openzfs/lib/libspl/os/linux/getmntany.c (revision 4543ef516683042d46f3bd3bb8a4f3f746e00499)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or https://opensource.org/licenses/CDDL-1.0.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24  * Copyright 2006 Ricardo Correia.  All rights reserved.
25  * Use is subject to license terms.
26  */
27 
28 /*	Copyright (c) 1988 AT&T	*/
29 /*	  All Rights Reserved	*/
30 
31 #include <stdio.h>
32 #include <string.h>
33 #include <mntent.h>
34 #include <sys/errno.h>
35 #include <sys/mnttab.h>
36 
37 #include <sys/types.h>
38 #include <sys/sysmacros.h>
39 #include <sys/stat.h>
40 #include <unistd.h>
41 #include <libzutil.h>
42 
43 #define	BUFSIZE	(MNT_LINE_MAX + 2)
44 
45 static __thread char buf[BUFSIZE];
46 
47 #define	DIFF(xx)	( \
48 	    (mrefp->xx != NULL) && \
49 	    (mgetp->xx == NULL || strcmp(mrefp->xx, mgetp->xx) != 0))
50 
51 int
52 getmntany(FILE *fp, struct mnttab *mgetp, struct mnttab *mrefp)
53 {
54 	int ret;
55 
56 	while (
57 	    ((ret = _sol_getmntent(fp, mgetp)) == 0) && (
58 	    DIFF(mnt_special) || DIFF(mnt_mountp) ||
59 	    DIFF(mnt_fstype) || DIFF(mnt_mntopts))) { }
60 
61 	return (ret);
62 }
63 
64 int
65 _sol_getmntent(FILE *fp, struct mnttab *mgetp)
66 {
67 	struct mntent mntbuf;
68 	struct mntent *ret;
69 
70 	ret = getmntent_r(fp, &mntbuf, buf, BUFSIZE);
71 
72 	if (ret != NULL) {
73 		mgetp->mnt_special = mntbuf.mnt_fsname;
74 		mgetp->mnt_mountp = mntbuf.mnt_dir;
75 		mgetp->mnt_fstype = mntbuf.mnt_type;
76 		mgetp->mnt_mntopts = mntbuf.mnt_opts;
77 		return (0);
78 	}
79 
80 	if (feof(fp))
81 		return (-1);
82 
83 	return (MNT_TOOLONG);
84 }
85 
86 static int
87 getextmntent_impl(FILE *fp, struct extmnttab *mp)
88 {
89 	int ret;
90 	struct stat64 st;
91 
92 	ret = _sol_getmntent(fp, (struct mnttab *)mp);
93 	if (ret == 0) {
94 		if (stat64(mp->mnt_mountp, &st) != 0) {
95 			mp->mnt_major = 0;
96 			mp->mnt_minor = 0;
97 			return (ret);
98 		}
99 		mp->mnt_major = major(st.st_dev);
100 		mp->mnt_minor = minor(st.st_dev);
101 	}
102 
103 	return (ret);
104 }
105 
106 int
107 getextmntent(const char *path, struct extmnttab *entry, struct stat64 *statbuf)
108 {
109 	struct stat64 st;
110 	FILE *fp;
111 	int match;
112 
113 	if (strlen(path) >= MAXPATHLEN) {
114 		(void) fprintf(stderr, "invalid object; pathname too long\n");
115 		return (-1);
116 	}
117 
118 	/*
119 	 * Search for the path in /proc/self/mounts. Rather than looking for the
120 	 * specific path, which can be fooled by non-standard paths (i.e. ".."
121 	 * or "//"), we stat() the path and search for the corresponding
122 	 * (major,minor) device pair.
123 	 */
124 	if (stat64(path, statbuf) != 0) {
125 		(void) fprintf(stderr, "cannot open '%s': %s\n",
126 		    path, zfs_strerror(errno));
127 		return (-1);
128 	}
129 
130 
131 	if ((fp = fopen(MNTTAB, "re")) == NULL) {
132 		(void) fprintf(stderr, "cannot open %s\n", MNTTAB);
133 		return (-1);
134 	}
135 
136 	/*
137 	 * Search for the given (major,minor) pair in the mount table.
138 	 */
139 
140 	match = 0;
141 	while (getextmntent_impl(fp, entry) == 0) {
142 		if (makedev(entry->mnt_major, entry->mnt_minor) ==
143 		    statbuf->st_dev) {
144 			match = 1;
145 			break;
146 		}
147 	}
148 	(void) fclose(fp);
149 
150 	if (!match) {
151 		(void) fprintf(stderr, "cannot find mountpoint for '%s'\n",
152 		    path);
153 		return (-1);
154 	}
155 
156 	if (stat64(entry->mnt_mountp, &st) != 0) {
157 		entry->mnt_major = 0;
158 		entry->mnt_minor = 0;
159 		return (-1);
160 	}
161 
162 	return (0);
163 }
164