Start 1.33.0 development cycle

[oweals/busybox.git] / libbb / find_mount_point.c

diff --git a/libbb/find_mount_point.c b/libbb/find_mount_point.c
index b6320385217fef48a9ff43ae39492b6737e12435..0e1be38204541c79c3bf49f9ebb8f331b31bbba5 100644 (file)
--- a/libbb/find_mount_point.c
+++ b/libbb/find_mount_point.c
@@ -2,29 +2,13 @@
 /*
  * Utility routines.
  *
- * Copyright (C) 1999-2003 by Erik Andersen <andersen@codepoet.org>
+ * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
-
-#include <stdio.h>
-#include <string.h>
 #include "libbb.h"
-
-
 #include <mntent.h>
+
 /*
  * Given a block device, find the mount table entry if that block device
  * is mounted.
@@ -32,44 +16,64 @@
  * Given any other file (or directory), find the mount table entry for its
  * filesystem.
  */
-extern struct mntent *find_mount_point(const char *name, const char *table)
+struct mntent* FAST_FUNC find_mount_point(const char *name, int subdir_too)
 {
        struct stat s;
-       dev_t mountDevice;
-       FILE *mountTable;
+       FILE *mtab_fp;
        struct mntent *mountEntry;
+       dev_t devno_of_name;
+       bool block_dev;
 
        if (stat(name, &s) != 0)
-               return 0;
+               return NULL;
 
-       if ((s.st_mode & S_IFMT) == S_IFBLK)
-               mountDevice = s.st_rdev;
-       else
-               mountDevice = s.st_dev;
+       devno_of_name = s.st_dev;
+       block_dev = 0;
+       /* Why S_ISCHR? - UBI volumes use char devices, not block */
+       if (S_ISBLK(s.st_mode) || S_ISCHR(s.st_mode)) {
+               devno_of_name = s.st_rdev;
+               block_dev = 1;
+       }
 
+       mtab_fp = setmntent(bb_path_mtab_file, "r");
+       if (!mtab_fp)
+               return NULL;
 
-       if ((mountTable = setmntent(table, "r")) == 0)
-               return 0;
+       while ((mountEntry = getmntent(mtab_fp)) != NULL) {
+               /* rootfs mount in Linux 2.6 exists always,
+                * and it makes sense to always ignore it.
+                * Otherwise people can't reference their "real" root! */
+               if (ENABLE_FEATURE_SKIP_ROOTFS && strcmp(mountEntry->mnt_fsname, "rootfs") == 0)
+                       continue;
 
-       while ((mountEntry = getmntent(mountTable)) != 0) {
                if (strcmp(name, mountEntry->mnt_dir) == 0
-                       || strcmp(name, mountEntry->mnt_fsname) == 0)   /* String match. */
+                || strcmp(name, mountEntry->mnt_fsname) == 0
+               ) { /* String match. */
                        break;
-               if (stat(mountEntry->mnt_fsname, &s) == 0 && s.st_rdev == mountDevice)  /* Match the device. */
+               }
+
+               if (!(subdir_too || block_dev))
+                       continue;
+
+               /* Is device's dev_t == name's dev_t? */
+               if (mountEntry->mnt_fsname[0] == '/'
+               /* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+                * avoid stat'ing "sysfs", "proc", "none" and such,
+                * useless at best, can stat unrelated files at worst.
+                */
+                && stat(mountEntry->mnt_fsname, &s) == 0
+                && s.st_rdev == devno_of_name
+               ) {
                        break;
-               if (stat(mountEntry->mnt_dir, &s) == 0 && s.st_dev == mountDevice)      /* Match the directory's mount point. */
+               }
+               /* Match the directory's mount point. */
+               if (stat(mountEntry->mnt_dir, &s) == 0
+                && s.st_dev == devno_of_name
+               ) {
                        break;
+               }
        }
-       endmntent(mountTable);
+       endmntent(mtab_fp);
+
        return mountEntry;
 }
-
-
-/* END CODE */
-/*
-Local Variables:
-c-file-style: "linux"
-c-basic-offset: 4
-tab-width: 4
-End:
-*/