Re: Regrading Tweaking chmod binary

[Bernhard Voelker]

On 01/28/2017 09:37 AM, Rohit Sehgal wrote:
> I am a post graduate student at IIT Kanpur. I am currently working to 
> build a android system that is capable of changing permissions of any 
> file. I am clear with all sort of stuff that i will be doing after 
> changing permissions, but currently I am stucked at place, where i want 
> to tweak chmod.c file so that it could any file permission. I tried 
> reading the code at coreutils git repo, but very much unclear about it.
> Can any one help me changing that chmod.c code such a way that if i 
> input any file to utility then the permissions are changed accordingly.
> Lastly i want to build this system for android's chmod. I request you to 
> please help in doing this as it will be a great help to my thesis work. 
> Or lead me to a proper path.

I'm afraid I do not understand the problem.  You only mentioned that
you want to be able to change the file permissions ... well, that's
what chmod is actually doing.  For what it's worth, the chmod(1) command
line utility from coreutils invokes chmod() system call.  So whatever
problem you might have with it, the kernel might impose some restrictions
for this.  I do not know Android much, so I can't help you here.

After all, you did not describe the problem enough.  What exactly are you
trying to achive (intial situation)?  How are you doing that (code, please)?
What is the outcome (error diagnostics, resulting permissions)?  And what
exactly would you wish/expect to be/become different?

Have a nice day,
Berny