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 http://www.opensolaris.org/os/licensing.
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  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*
30  * Attempt to dynamically link in the ZFS libzfs.so.1 so that we can
31  * see if there are any ZFS zpools on any of the slices.
32  */
33 
34 #include <stdlib.h>
35 #include <stdio.h>
36 #include <strings.h>
37 #include <sys/param.h>
38 #include <sys/errno.h>
39 #include <sys/types.h>
40 #include <sys/stat.h>
41 #include <fcntl.h>
42 #include <thread.h>
43 #include <synch.h>
44 #include <dlfcn.h>
45 #include <link.h>
46 #include <ctype.h>
47 
48 #include "libdiskmgt.h"
49 #include "disks_private.h"
50 
51 /*
52  * Pointers to libzfs.so functions that we dynamically resolve.
53  */
54 static	int	(*zfsdl_zpool_in_use)(int fd, char **desc, char **name);
55 
56 static mutex_t			init_lock = DEFAULTMUTEX;
57 static rwlock_t			zpool_lock = DEFAULTRWLOCK;
58 static	int			initialized = 0;
59 
60 static void	*init_zpool();
61 
62 int
63 inuse_zpool(char *slice, nvlist_t *attrs, int *errp)
64 {
65 	int		found = 0;
66 	char		*desc, *name;
67 	int		fd;
68 
69 	*errp = 0;
70 	if (slice == NULL) {
71 	    return (found);
72 	}
73 
74 	(void) mutex_lock(&init_lock);
75 
76 	/*
77 	 * Dynamically load libzfs
78 	 */
79 	if (!initialized) {
80 		if (!init_zpool()) {
81 			(void) mutex_unlock(&init_lock);
82 			return (found);
83 		}
84 		initialized = 1;
85 	}
86 	(void) mutex_unlock(&init_lock);
87 	(void) rw_rdlock(&zpool_lock);
88 	if ((fd = open(slice, O_RDONLY)) > 0) {
89 		if (zfsdl_zpool_in_use(fd, &desc, &name)) {
90 			libdiskmgt_add_str(attrs, DM_USED_BY,
91 				DM_USE_ZPOOL, errp);
92 			libdiskmgt_add_str(attrs, DM_USED_NAME,
93 				name, errp);
94 			found = 1;
95 		}
96 	}
97 	(void) rw_unlock(&zpool_lock);
98 
99 	return (found);
100 }
101 
102 /*
103  * Try to dynamically link the zfs functions we need.
104  */
105 static void*
106 init_zpool()
107 {
108 	void	*lh = NULL;
109 
110 	if ((lh = dlopen("libzfs.so", RTLD_NOW)) == NULL) {
111 		return (lh);
112 	}
113 	/*
114 	 * Instantiate the functions needed to get zpool configuration
115 	 * data
116 	 */
117 	if ((zfsdl_zpool_in_use = (int (*)(int, char **, char **))dlsym(lh,
118 	    "zpool_in_use")) == NULL) {
119 		(void) dlclose(lh);
120 		return (NULL);
121 	}
122 
123 	return (lh);
124 }
125