look data in stack area

[Breno]

Hi

I´d like to do a module that can look the data of stack area , and if it
search a specific  code , it will do something.

i.e.

1º Process A is running
2º A module is looking data in stack area
3º A /bin/sh code was found
4º Module do something with this process.

My question is :  how can i look the data of stack area with a module ?
Can you give me some opinions , please ?

Thanks
Breno