external/bsd/am-utils/dist/conf/checkmount/checkmount_default.c

   1 /*      $NetBSD$        */
   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 }