[SOLVED] Can we change Entries in the inode table of a file (Linux)

kingkashif · 05-19-2011, 07:15 AM

Hello,

Anyone, I would like to ask if it was possible to change the entries of a file's inode table ?

For example

Code:

File: `index.php'
  Size: 38        	Blocks: 8          IO Block: 4096   regular file
Device: 807h/2055d	Inode: 164744      Links: 1
Access: (0644/-rw-r--r--)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2011-05-19 16:32:01.939059278 +0500
Modify: 2011-05-19 17:03:54.518074785 +0500
Change: 2011-05-19 17:03:54.518074785 +0500

Now the above is the inode stat of the index.php's file.

I was wondering if I can change the entries in this inode table's entries.
For example I want to change the "Modify" entry ? I want it to reflect to day 2009-05-19 for example.

Can i do it ?

catkin · 05-19-2011, 07:17 AM

If you want to do it from the command prompt or in a script that can run commands, the touch command can do that.

kingkashif · 05-19-2011, 07:21 AM

Thank you for your reply..

Can you please elaborate how I could change the "modify" line of an inode table of a file to reflect the date my specified date ?

How can I do it using touch ?

Thanks

manyrootsofallevil · 05-19-2011, 07:46 AM

Quote:

Originally Posted by kingkashif

Thank you for your reply..

Can you please elaborate how I could change the "modify" line of an inode table of a file to reflect the date my specified date ?

How can I do it using touch ?

Thanks

You simply do

Code:

touch filename

catkin · 05-19-2011, 07:57 AM

Quote:

Originally Posted by kingkashif

How can I do it using touch ?

Most commands have a "man page" (man = manual). To see the touch man page run man touch.

Many commands have "info" too so it is worth trying info coreutils 'touch invocation'

The Internet often has pages explaining how to use commands; here is a Google Linux search for the words touch, command and example.

kingkashif · 05-19-2011, 10:09 AM

Well thanks for your replies but I guess you guys have misunderstood me, or just didn't read the question well.

I know how to use the touch commands etc, I am not a newbie.

Here is the question Again ..

When I run following command

Code:

stat index.php

as a result of above command, I get following result

Code:

File: `index.php'
  Size: 38        	Blocks: 8          IO Block: 4096   regular file
Device: 807h/2055d	Inode: 164744      Links: 1
Access: (0644/-rw-r--r--)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2011-05-19 16:32:01.939059278 +0500
Modify: 2011-05-19 17:03:54.518074785 +0500
Change: 2011-05-19 17:03:54.518074785 +0500

now you see there are various entries in this inode table of file index.php

I am wondering if there is a way I can hack these entries ?

for example I want to change the "Modify:" line in this table

and I want to set the date in the "Modify:" line of this table to reflect 2001-04-19
instead of it's current value 2011-05-19 ..

is it possible ?

Have you guys understood my problem now ?

OlRoy · 05-19-2011, 10:58 AM

I'm pretty sure they understand what you're asking, and have already answered it. Can I ask why you want to change the modified time?

manyrootsofallevil · 05-20-2011, 01:55 AM

Quote:

Originally Posted by kingkashif

Well thanks for your replies but I guess you guys have misunderstood me, or just didn't read the question well.

I know how to use the touch commands etc, I am not a newbie.

Here is the question Again ..

When I run following command

Code:

stat index.php

as a result of above command, I get following result

Code:

File: `index.php'
  Size: 38        	Blocks: 8          IO Block: 4096   regular file
Device: 807h/2055d	Inode: 164744      Links: 1
Access: (0644/-rw-r--r--)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2011-05-19 16:32:01.939059278 +0500
Modify: 2011-05-19 17:03:54.518074785 +0500
Change: 2011-05-19 17:03:54.518074785 +0500

now you see there are various entries in this inode table of file index.php

I am wondering if there is a way I can hack these entries ?

for example I want to change the "Modify:" line in this table

and I want to set the date in the "Modify:" line of this table to reflect 2001-04-19
instead of it's current value 2011-05-19 ..

is it possible ?

Have you guys understood my problem now ?

This should modify the Modify entry only

Code:

touch -m --date='2001-04-19' index.php

catkin · 05-20-2011, 02:08 AM

Quote:

Originally Posted by kingkashif

for example I want to change the "Modify:" line in this table

and I want to set the date in the "Modify:" line of this table to reflect 2001-04-19
instead of it's current value 2011-05-19 ..

is it possible ?

Yes -- it is possible. The easiest way is to use the touch command. Why do you not want to do it that way? Do you want to write a program to do what the touch command does? Do you want to find the location of the data on HDD and change it directly?

kingkashif · 05-21-2011, 02:34 PM

thanks for your help guys. It's great to finally know it.

I would like to know whether I could know this file's location directly on HDD?

Can I open that file from there and change it instead ?

Thanks

catkin · 05-22-2011, 12:26 AM

Quote:

Originally Posted by kingkashif

I would like to know whether I could know this file's location directly on HDD?

Can I open that file from there and change it instead ?

Thanks

It is technically possible but difficult to locate and modify an inode on HDD. The specifics depend on the file system type.

Why do you want to do so when the touch command can do exactly what you want and a lot more easily?

Please be aware of LQ's rule "Posts containing information about cracking, piracy, warez, fraud or any topic that could be damaging to either LinuxQuestions.org or any third party will be immediately removed". You are unlikely to get much help here unless you convince us you are not breaking that rule.

kingkashif · 05-24-2011, 03:09 AM

Well actually I am not breaking any rules..

I was just wondering, if all the entries in the inode table of a file
are editable by the owner of that file ? Or there are any entries that
can only be modified by the kernel only.

Thats all.

catkin · 05-24-2011, 08:59 AM

The straighforward way to alter file system data is by system calls to the kernel (which may be generated by commands such as rm, ln, touch etc., via a shell's redirection operators such as >, via a GUI or from a program using system call libraries such as compiled C) which then alters the file system data via file system drivers. In this case the file and directory permissions control which users can change the data.

Alternatively you can write directly to the HDD via its block device files such as /dev/sda, /dev/sda2 etc. using something like the dd command. This requires a knowledge of the file system structure to determine the position of the data (including inode) to be changed. A mistake can corrupt the file system. If it is done while the file system is mounted the usual issues of multi-write access causing data skew arise. The HDD's block device files are writeable only by root so only root can do this.

kingkashif · 05-25-2011, 03:58 AM

Okay thank you catkin for your generous time.

This post stands resolved now.

Thanks everyone else, who shared their views here.