hush/libbb/find_mount_point.c
Javier Viguera ce4f39ac7c find_mount_point: fix find_mount_point for char devices
This allows to find mount points of 'char' devices such as UBI volumes
which otherwise fail for example with 'df' command:

/ # df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/root             72091984  12360980  56068924  18% /
devtmpfs                115236         4    115232   0% /dev
tmpfs                    28672        32     28640   0% /tmp
/dev/ubi0_0             360268     18348    341920   5% /tmp/mnt/userfs

/ # df /dev/ubi0_0
Filesystem           1K-blocks      Used Available Use% Mounted on
devtmpfs                115236         4    115232   0% /dev

Signed-off-by: Javier Viguera <javier.viguera@digi.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2012-01-18 01:49:11 +01:00

70 lines
1.7 KiB
C

/* 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 (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;
}