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lib/ismounted: basic support for loop devices 

# losetup -a /dev/loop0
 /dev/loop0: [2053]:1048578 (/home/fs-images/filesystems/ext2.img)

 # findmnt /dev/loop0
 TARGET    SOURCE     FSTYPE OPTIONS
 /mnt/test /dev/loop0 ext3   rw,relatime,data=ordered

old version:

 ./test_ismounted /home/fs-images/filesystems/ext2.img
 not mounted

new version:

 ./test_ismounted /home/fs-images/filesystems/ext2.img
 mounted on /mnt/test

Reported-by: Sami Kerola <kerolasa@iki.fi>
Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak 2012-12-19 12:40:32 +01:00
parent 06f588f7d1
commit ca4f6229b0
3 changed files with 36 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
disk-utils/Makemodule.am
View File

@ -3,8 +3,7 @@ sbin_PROGRAMS += fsck.minix
dist_man_MANS += disk-utils/fsck.minix.8
fsck_minix_SOURCES = \
disk-utils/fsck.minix.c \
disk-utils/minix_programs.h \
lib/ismounted.c
disk-utils/minix_programs.h
fsck_minix_LDADD = $(LDADD) libcommon.la
sbin_PROGRAMS += mkfs.minix

1
lib/Makemodule.am
View File

@ -76,6 +76,7 @@ test_blkdev_LDADD = libcommon.la
test_ismounted_SOURCES = lib/ismounted.c
test_ismounted_CFLAGS = -DTEST_PROGRAM
test_ismounted_LDADD = libcommon.la
test_wholedisk_SOURCES = lib/wholedisk.c
test_wholedisk_CFLAGS = -DTEST_PROGRAM

44
lib/ismounted.c
View File

@ -26,6 +26,11 @@
#include "pathnames.h"
#include "ismounted.h"
#include "c.h"
#ifdef __linux__
# include "loopdev.h"
#endif
#ifdef HAVE_MNTENT_H
/*
@ -39,7 +44,7 @@ static int check_mntent_file(const char *mtab_file, const char *file,
struct mntent *mnt;
struct stat st_buf;
int retval = 0;
dev_t file_dev=0, file_rdev=0;
dev_t file_dev=0, file_rdev=0, lodev_dev=0;
ino_t file_ino=0;
FILE *f;
int fd;
@ -47,32 +52,51 @@ static int check_mntent_file(const char *mtab_file, const char *file,
*mount_flags = 0;
if ((f = setmntent (mtab_file, "r")) == NULL)
return errno;
if (stat(file, &st_buf) == 0) {
if (S_ISBLK(st_buf.st_mode)) {
#ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */
file_rdev = st_buf.st_rdev;
#endif /* __GNU__ */
} else {
#ifdef __linux__
/*
* Maybe the file is backing file for a loop device.
*
* For is_mounted() we complete ignore the fact that
* the same backing file maybe mapped into more loop
* devices by sizelimit and offset loop options. If you
* want really robust code than use libmount...
*/
char *name = loopdev_find_by_backing_file(file, 0, 0);
if (name && stat(name, &st_buf) == 0)
lodev_dev = st_buf.st_rdev;
free(name);
#endif
file_dev = st_buf.st_dev;
file_ino = st_buf.st_ino;
}
}
while ((mnt = getmntent (f)) != NULL) {
if (mnt->mnt_fsname[0] != '/')
continue;
if (strcmp(file, mnt->mnt_fsname) == 0)
break;
if (stat(mnt->mnt_fsname, &st_buf) == 0) {
if (S_ISBLK(st_buf.st_mode)) {
if (stat(mnt->mnt_fsname, &st_buf) != 0)
continue;
if (S_ISBLK(st_buf.st_mode)) {
#ifndef __GNU__
if (file_rdev && (file_rdev == st_buf.st_rdev))
break;
#endif /* __GNU__ */
} else {
if (file_dev && ((file_dev == st_buf.st_dev) &&
(file_ino == st_buf.st_ino)))
break;
if ((file_rdev && file_rdev == st_buf.st_rdev) ||
(lodev_dev && lodev_dev == st_buf.st_rdev)) {
break;
}
#endif /* __GNU__ */
} else {
if (file_dev && ((file_dev == st_buf.st_dev) &&
(file_ino == st_buf.st_ino)))
break;
}
}