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From:   Pintu Agarwal <pintu.ping@gmail.com>
Date:   Thu, 13 Jun 2019 13:13:21 +0530
Message-ID: <CAOuPNLifSHQmi+jCMzRGYz3kzct+NB_vyv-yiwL91adRZPkTrQ@mail.gmail.com>
Subject: Pause a process execution from external program
To:     kernelnewbies@kernelnewbies.org,
        open list <linux-kernel@vger.kernel.org>, pedro@palves.net
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Hi All,
I was just wondering if this is possible in the Linux world.
My requirement is:
For some reason, I want to halt/pause the execution (for some
specified time) of a running process/thread (at some location),
without modified the source, may be by firing some events/signals from
an another external program, by specifying the address location or a
line number.

Is this possible ?
May be by using some system call, or other mechanism using the process PID.
Assume that its a debugging system with all root privileges.

Basically, its just like how "gdb" is able to set the break-point in a
program, and able to stop its execution exactly at that location.
I am wondering what mechanism "gdb" uses to do this?
I tried to check here, but could find the exact place, where this is handled:
https://github.com/bminor/binutils-gdb/blob/master/gdb/breakpoint.c

Unfortunately, I cannot use "gdb", but I wanted to borrow this
mechanism only to serve my purpose.

If anyone is aware, please let me know.
I will share my findings here, after I get some useful results of my
experimentation.

Thank you for your help!


Regards,
Pintu