Add a cyclic -d --detect flag to find cyclic pattern offset in registers and stack memory

[nthdeg]

EDIT by @disconnect3d: The purpose of this issue is to track a new feature: adding a -d --detect flag to cyclic command so that it looks up the pattern offsets in registers and memory and prints this info to the user.

An offset finding function to auto detect the cyclic input in order to return the offset value.

gdb-peda has this feature (pattern_offset 0xdeadbeef) and would like to request this be implemented if possible.

ref:

          @nthdeg Added the `[filename]` argument to `cyclic` command in #2009.

So you can now do:

cyclic 100 input
run < input
cyclic -l 0xdeadbeef

(replace 0xdeadbeef with some cyclic pattern value)

We still need some kind of cyclic -d|--detect to auto detect the cyclic pattern values in registers and/or stack though.

Originally posted by @disconnect3d in #2007 (comment)

[disconnect3d]

Hi, I changed the title and added a first line to this issue to make it clear what we want to track here with this issue :).

[peace-maker]

Seems like a duplicate of #1965

[disconnect3d]

Oh, thanks for pointing out. Closing since its a duplicate.