Hi,

i'm having trouble generating core dumps for a certain program.
In general i can get a core dump. When running "kill -SIGILL $$" i
end up with a nice shining core file of my current shell. So in
principal it works but when doing the same thing to the program
i would like to debug no core dump is generated (it just quits).

The ulimit for core files is unlimited and the current working
directory is writeable. What else could be the problem that no
core dump is generated?

Can a program do something that prevents coredump generation?

Thanks.

Regards,
Frank

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Frank Meerkötter wrote:

> Can a program do something that prevents coredump generation?

On AIX a program can prevent coredumping by setting the SA_NODUMP flag
with sigaction() for every appropriate signal.

--
mail1dotstofanetdotdk

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Bjorn Reese wrote:
> Frank Meerk=F6tter wrote:

Hi,
 
>
> On AIX a program can prevent coredumping by setting the SA_NODUMP flag
> with sigaction() for every appropriate signal.

The system i'm running on is linux (2.6) which doesn't have this flag.

Thanks for reply.

Regards,
Frank

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"Frank Meerkötter" <frank@betaversion.net> writes:

> Can a program do something that prevents coredump generation?

On any UNIX system, a program can establish signal handler for all
core-dumping signals, and call _exit() when that handler is invoked.

Since you are on linux, run the program under strace and see if in
fact it does that for SIGILL. If so, see if it also does that for
other core-dumping signals (usually SIGQUIT is the signal you'll
want to send -- its *only* reason is to stop program with a core).

Cheers,
--
In order to understand recursion you must first understand recursion.
Remove /-nsp/ for email.

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2006-06-03 <1149345627.647575.136850@y43g2000cwc.googlegroups.com>,
Frank Meerkötter wrote:
> Hi,
>
> i'm having trouble generating core dumps for a certain program.
> In general i can get a core dump. When running "kill -SIGILL $$" i
> end up with a nice shining core file of my current shell. So in
> principal it works but when doing the same thing to the program
> i would like to debug no core dump is generated (it just quits).
>
> The ulimit for core files is unlimited and the current working
> directory is writeable. What else could be the problem that no
> core dump is generated?
>
> Can a program do something that prevents coredump generation?

it might be setting its own ulimit.

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Paul Pluzhnikov wrote:
> "Frank Meerk=F6tter" <frank@betaversion.net> writes:
> 
>
> On any UNIX system, a program can establish signal handler for all
> core-dumping signals, and call _exit() when that handler is invoked.

One can also block all ignorable signals using sigprocmask().

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"Maxim Yegorushkin" <maxim.yegorushkin@gmail.com> writes:

> One can also block all ignorable signals using sigprocmask().

True. However that is *not* what's happening to the OP program, since
it "just quits". If it blocked SIGILL, it would "just keep running".

Cheers,
--
In order to understand recursion you must first understand recursion.
Remove /-nsp/ for email.

[ Post a follow-up to this message ]

>
> Can a program do something that prevents coredump generation?
>

Yes. The program can prevent coredump generation by calling setrlimit.

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In article <e5t2uj$tqe$1@news3.zwoll1.ov.home.nl>,
"Bas" <no-email@forme.nl> wrote:
 
>
> Yes. The program can prevent coredump generation by calling setrlimit.

Another thing that will prevent core dumps is if the program is setuid.

--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
*** PLEASE don't copy me on replies, I'll read them in the group ***

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2006-06-04 <barmar-E9421C.21424703062006@comcast.dca.giganews.com>,
Barry Margolin wrote:
> In article <e5t2uj$tqe$1@news3.zwoll1.ov.home.nl>,
>  "Bas" <no-email@forme.nl> wrote:
> 
>
> Another thing that will prevent core dumps is if the program is setuid.

That would also prevent him sending signals

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