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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
#include "libbb.h"
#include <mntent.h>
/*
* Given a block device, find the mount table entry if that block device
* is mounted.
*
* Given any other file (or directory), find the mount table entry for its
* filesystem.
*/
struct mntent* FAST_FUNC find_mount_point(const char *name, int subdir_too)
{
struct stat s;
FILE *mtab_fp;
struct mntent *mountEntry;
dev_t devno_of_name;
bool block_dev;
if (stat(name, &s) != 0)
return NULL;
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;
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;
if (strcmp(name, mountEntry->mnt_dir) == 0
|| strcmp(name, mountEntry->mnt_fsname) == 0
) { /* String match. */
break;
}
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;
}
/* Match the directory's mount point. */
if (stat(mountEntry->mnt_dir, &s) == 0
&& s.st_dev == devno_of_name
) {
break;
}
}
endmntent(mtab_fp);
return mountEntry;
}
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