Remy Blank wrote:
Yahya Mohammad wrote:
# losetup /dev/loop0 /path/to/diskimage
# fdisk -l /dev/loop0
(example)
Disk /dev/sdb: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdb1 * 1 1044 8385898+ c W95 FAT32 (LBA)
/dev/sdb2 1045 19457 147902422+ 83 Linux
Thanks for the tip! I didn't know you could mount a whole disk image as
loopback, and see the partition table with fdisk. I always printed the
partition table before making the disk image.
I second that, I'm curious to know if it works
It does, I have done it before, but there's a special case for the first
partition of the disk. According to your output of fdisk, it is supposed
to start at cylinder 1. However, if you run fdisk with the -u option
(giving the positions and sizes in sectors), you get the following:
(example)
# fdisk -lu /dev/loop0
Disk /dev/loop0: 10.0 GB, 10056130560 bytes
240 heads, 63 sectors/track, 1299 cylinders, total 19640880 sectors
Units = sectors of 1 * 512 = 512 bytes
Disk identifier: 0xc1afc1af
Device Boot Start End Blocks Id System
/dev/loop0p1 * 63 4097519 2048728+ b W95 FAT32
/dev/loop0p2 4097520 8195039 2048760 5 Extended
/dev/loop0p5 4097583 8195039 2048728+ b W95 FAT32
That is, the first partition starts at sector 63, i.e. at an offset
value of 63 * 512 = 32256.
oh, and make a backup just in case :)
And mount the filesystem read-only with the "ro" mount option.
-- Remy
Some time ago, I wrote a little script to automate that process, maybe
it will help you also. (And yes, I know that the code isn't that pretty)
Direct copy & paste:
#!/bin/bash
INFILE="$1"
PARTITION="$2"
MOUNTPOINT="$3"
OPT="$4"
if [ "$INFILE" = "" ] ; then echo "Usage: $0 infile partition mountpoint
<options>" ; exit ; fi
if [ "$PARTITION" = "" ] ; then echo "Usage: $0 infile partition
mountpoint <options>" ; exit ; fi
if [ "$MOUNTPOINT" = "" ] ; then echo "Usage: $0 infile partition
mountpoint <options>" ; exit ; fi
if [ "$OPT" != "" ] ; then OPT2=",${OPT}" ; fi
PSTARTB=`sfdisk -d "$INFILE" | grep "start=" | head -n"$PARTITION" |
tail -n1 | sed 's/.*start=[ ]*//' | sed 's/,.*//'`
PSTART=$[ $PSTARTB * 512 ]
#PSIZEB=`sfdisk -d "$INFILE" | grep "size=" | head -n4 | tail -n1 | sed
's/.*size=[ ]*//' | sed 's/,.*//'`
#PSIZE=`echo "$PSIZEB * 512" | bc`
mount "$INFILE" "$MOUNTPOINT" -o loop,offset="$PSTART""$OPT2"
#,sizelimit="$PSIZE""$OPT2"
- Tom
--
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