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Re: how GDB use ptrace to return from a function
- From: Joel Brobecker <brobecker at adacore dot com>
- To: Yubin Ruan <ablacktshirt at gmail dot com>
- Cc: gdb at sourceware dot org
- Date: Fri, 17 Nov 2017 08:10:59 -0800
- Subject: Re: how GDB use ptrace to return from a function
- Authentication-results: sourceware.org; auth=none
- References: <CAJYFCiMqA1NO-32g7_vrwpU-h7dmyPaqUe=UZzey1gfFz7ax3g@mail.gmail.com>
> I don't know whether GDB is using this kind of technique. If anyone
> know that, can you enlighten me, and probably point me to the source?
GDB sets the call up so that the return address is at specific
location (usually the program's entry point, but that's arch-
dependent), and then places a breakpoint at that address. It
then knows, when receiving the corresponding breakpoint event,
that a breakpoint at that address corresponds to the end of
the function that we called.
--
Joel