Crash log

Crash log

[Robin Rowe]

Hi. This isn't really a gdb question, but I don't know where else to ask.

When a program catches a bad signal such as SIGSEGV I want to write a crash
log entry before the program exits. Is there anything useful I can put in
the log besides the name of the program and when it crashed? Is it ok to
write this log from my signal catcher, or should it first fork?

Is there some kind of useful state info (assuming the program contains no
debugging info) that I can write to a log file at the time of death? Can I
get an instruction pointer that I can relate back to the original souce
somehow to determine what line of code crashed?

Thanks!

Robin
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Robin.Rowe@MovieEditor.com   Hollywood, California
www.CinePaint.org   Free motion picture and still image editing software

Re: Crash log

[Eli Zaretskii]

> From: "Robin Rowe" <rower@MovieEditor.com>
> Date: Mon, 22 Sep 2003 13:46:08 -0700
> 
> When a program catches a bad signal such as SIGSEGV I want to write a crash
> log entry before the program exits. Is there anything useful I can put in
> the log besides the name of the program and when it crashed?

Yes, you can put there the address of the faulting instruction.  Use
the Posix `sigaction' rather than `signal' to install the signal
handler, and you will have access to the siginfo_t structure which
gives the address of the memory location that caused the fault and
other useful info.

Some systems have extensions to `signal' that allow the signal
handlers to access the same information.

> Is it ok to
> write this log from my signal catcher, or should it first fork?

It's probably okay in most cases to do this without forking, although
some calamities such as smashed stack might cause another fault in the
code that writes the data.  But then fork will probably fail in that
case as well.