Date: Fri, 24 Nov 1995 11:04:51 +0100 (MET) From: grog@lemis.de (Greg Lehey) To: gavin@linux1.dlsu.edu.ph (Gavin Chan Lim) Subject: Re: ptrace() Message-ID: <199511241005.LAA24697@allegro.lemis.de> In-Reply-To: <Pine.LNX.3.91.951123133345.1208B-100000@ccslinux.dlsu.edu.ph> from "Gavin Chan Lim" at Nov 23, 95 01:36:09 pm
next in thread | previous in thread | raw e-mail | index | archive | help
Gavin Chan Lim writes: > I've found the source codes for GDB. I have certain questions regarding > ptrace(). I hope you can answer them. > > 1. What does "Attach/Detach to the process" mean? (PT_ATTACH, PT_DETACH)> > 2. Does request PT_READ_I mean read the text segment? Yes, On the PDP-11. On the i386, it means read the process address space. > 3. Does request PT_READ_D mean read the data segment? Yes, On the PDP-11. On the i386, it means read the process address space. You'll notice that Linux has done away with the difference between these two, which are redundant, but this is UNIX :-) > 4. What's the last argument (int data) of ptrace() for? It's used to pass data where necessary: PT_CONTINUE - specify a signal number to be sent to the child process before it continues. 0 means don't send a signal. PT_WRITE_U - data to be written to the user area PT_WRITE_I - data to be written to the process data space PT_WRITE_D - data to be written to the process data space Greg
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199511241005.LAA24697>