xref: /freebsd/sys/contrib/openzfs/lib/libspl/os/linux/getmntany.c (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
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 
42 #define	BUFSIZE	(MNT_LINE_MAX + 2)
43 
44 static __thread char buf[BUFSIZE];
45 
46 #define	DIFF(xx)	( \
47 	    (mrefp->xx != NULL) && \
48 	    (mgetp->xx == NULL || strcmp(mrefp->xx, mgetp->xx) != 0))
49 
50 int
51 getmntany(FILE *fp, struct mnttab *mgetp, struct mnttab *mrefp)
52 {
53 	int ret;
54 
55 	while (
56 	    ((ret = _sol_getmntent(fp, mgetp)) == 0) && (
57 	    DIFF(mnt_special) || DIFF(mnt_mountp) ||
58 	    DIFF(mnt_fstype) || DIFF(mnt_mntopts))) { }
59 
60 	return (ret);
61 }
62 
63 int
64 _sol_getmntent(FILE *fp, struct mnttab *mgetp)
65 {
66 	struct mntent mntbuf;
67 	struct mntent *ret;
68 
69 	ret = getmntent_r(fp, &mntbuf, buf, BUFSIZE);
70 
71 	if (ret != NULL) {
72 		mgetp->mnt_special = mntbuf.mnt_fsname;
73 		mgetp->mnt_mountp = mntbuf.mnt_dir;
74 		mgetp->mnt_fstype = mntbuf.mnt_type;
75 		mgetp->mnt_mntopts = mntbuf.mnt_opts;
76 		return (0);
77 	}
78 
79 	if (feof(fp))
80 		return (-1);
81 
82 	return (MNT_TOOLONG);
83 }
84 
85 static int
86 getextmntent_impl(FILE *fp, struct extmnttab *mp)
87 {
88 	int ret;
89 	struct stat64 st;
90 
91 	ret = _sol_getmntent(fp, (struct mnttab *)mp);
92 	if (ret == 0) {
93 		if (stat64(mp->mnt_mountp, &st) != 0) {
94 			mp->mnt_major = 0;
95 			mp->mnt_minor = 0;
96 			return (ret);
97 		}
98 		mp->mnt_major = major(st.st_dev);
99 		mp->mnt_minor = minor(st.st_dev);
100 	}
101 
102 	return (ret);
103 }
104 
105 int
106 getextmntent(const char *path, struct extmnttab *entry, struct stat64 *statbuf)
107 {
108 	struct stat64 st;
109 	FILE *fp;
110 	int match;
111 
112 	if (strlen(path) >= MAXPATHLEN) {
113 		(void) fprintf(stderr, "invalid object; pathname too long\n");
114 		return (-1);
115 	}
116 
117 	/*
118 	 * Search for the path in /proc/self/mounts. Rather than looking for the
119 	 * specific path, which can be fooled by non-standard paths (i.e. ".."
120 	 * or "//"), we stat() the path and search for the corresponding
121 	 * (major,minor) device pair.
122 	 */
123 	if (stat64(path, statbuf) != 0) {
124 		(void) fprintf(stderr, "cannot open '%s': %s\n",
125 		    path, strerror(errno));
126 		return (-1);
127 	}
128 
129 
130 	if ((fp = fopen(MNTTAB, "re")) == NULL) {
131 		(void) fprintf(stderr, "cannot open %s\n", MNTTAB);
132 		return (-1);
133 	}
134 
135 	/*
136 	 * Search for the given (major,minor) pair in the mount table.
137 	 */
138 
139 	match = 0;
140 	while (getextmntent_impl(fp, entry) == 0) {
141 		if (makedev(entry->mnt_major, entry->mnt_minor) ==
142 		    statbuf->st_dev) {
143 			match = 1;
144 			break;
145 		}
146 	}
147 	(void) fclose(fp);
148 
149 	if (!match) {
150 		(void) fprintf(stderr, "cannot find mountpoint for '%s'\n",
151 		    path);
152 		return (-1);
153 	}
154 
155 	if (stat64(entry->mnt_mountp, &st) != 0) {
156 		entry->mnt_major = 0;
157 		entry->mnt_minor = 0;
158 		return (-1);
159 	}
160 
161 	return (0);
162 }
163