[Rpm-maint] RFC: Unblocking of signals within rpm

Tomas Mraz tmraz at redhat.com
Thu Jul 19 10:47:52 UTC 2007

On Thu, 2007-07-19 at 13:30 +0300, Panu Matilainen wrote:
> On Thu, 19 Jul 2007, Michael Schroeder wrote:
> > On Thu, Jul 19, 2007 at 12:58:29PM +0300, Panu Matilainen wrote:
> >>
> >> Attached patch turns the signal handling within rpmdb upside down: we no
> >> longer run the whole damn thing with termination signals blocked with
> >> occasional checking possibly resulting in exit() from deep within rpmlib,
> >> but instead have an active signal handler that will mop up any open
> >> transactions and iterators and pass on the signal to caller.
> >
> > Whoa, doing complex things in a signal handler is very dangerous.
> > You can interrupt rpm deep inside some glibc function like "malloc".
> Yes, but then this is a terminating signal handler, and AFAICT does just 
> what's described in glibc manual as the cleanest way to handle this:
> http://www.gnu.org/software/libc/manual/html_node/Termination-in-Handler.html
But you should not in the signal handler for example call any function
which manipulates the heap (calling free() for example).

Tomas Mraz
No matter how far down the wrong road you've gone, turn back.
                                              Turkish proverb

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