1 /*	$NetBSD: checkmount_default.c,v 1.1.1.2 2009/03/20 20:26:50 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1997-2009 Erez Zadok
5  * Copyright (c) 1990 Jan-Simon Pendry
6  * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
7  * Copyright (c) 1990 The Regents of the University of California.
8  * All rights reserved.
9  *
10  * This code is derived from software contributed to Berkeley by
11  * Jan-Simon Pendry at Imperial College, London.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. All advertising materials mentioning features or use of this software
22  *    must display the following acknowledgment:
23  *      This product includes software developed by the University of
24  *      California, Berkeley and its contributors.
25  * 4. Neither the name of the University nor the names of its contributors
26  *    may be used to endorse or promote products derived from this software
27  *    without specific prior written permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39  * SUCH DAMAGE.
40  *
41  *
42  * File: am-utils/conf/checkmount/checkmount_default.c
43  *
44  */
45 
46 #ifdef HAVE_CONFIG_H
47 # include <config.h>
48 #endif /* HAVE_CONFIG_H */
49 #include <am_defs.h>
50 
51 #ifndef _PATH_MTAB
52 #define _PATH_MTAB "/etc/mtab"
53 #endif /* not _PATH_MTAB */
54 
55 extern int is_same_host(char *name1, char *name2, struct in_addr addr2);
56 
57 
58 int
59 fixmount_check_mount(char *host, struct in_addr hostaddr, char *path)
60 {
61   FILE *mtab;
62   mntent_t *ment;
63   int found = 0;
64 
65   /* scan mtab for path */
66   if (!(mtab = setmntent(_PATH_MTAB, "r"))) {
67     perror(_PATH_MTAB);
68     exit(1);
69   }
70 
71   /*
72    * setmntent() doesn't do locking in read-only mode. Too bad -- it seems to
73    * rely on mount() and friends to do atomic updates by renaming the file.
74    * Well, our patched amd rewrites mtab in place to avoid NFS lossage, so
75    * better do the locking ourselves.
76    */
77 #ifdef HAVE_FLOCK
78   if (flock(fileno(mtab), LOCK_SH) < 0) {
79 #else /* not HAVE_FLOCK */
80   if (lockf(fileno(mtab), F_LOCK, 0) < 0) {
81 #endif /* not HAVE_FLOCK */
82     perror(_PATH_MTAB);
83     exit(1);
84   }
85 
86   while (!found && (ment = getmntent(mtab))) {
87     char *colon;
88 
89     if ((colon = strchr(ment->mnt_fsname, ':'))) {
90       *colon = '\0';
91       if ((STREQ(colon + 1, path) ||
92 	   STREQ(ment->mnt_dir, path)) &&
93 	  is_same_host(ment->mnt_fsname, host, hostaddr))
94 	  found = 1;
95     }
96   }
97 
98   (void) endmntent(mtab);
99 
100   if (!found) {
101     char *swap;
102 
103     /* swap files never show up in mtab, only root fs */
104     if ((swap = strstr(path, "swap"))) {
105       strncpy(swap, "root", 4);	/* this should NOT use xstrlcpy  */
106       found = fixmount_check_mount(host, hostaddr, path);
107       strncpy(swap, "swap", 4);	/* this should NOT use xstrlcpy  */
108     }
109   }
110   return found;
111 }
112