Re: [APC-DEV] [PATCH] APC signals + coredump shared memory unmapping

Lucas Nealan wrote:
> Although this will technically work in production environments the
> functionality was engineered to solve a problem in shared development
> environments that require a really large apc shm size. In these environments
> when a coredump occurs in the SAPI, PHP or an extension the coredump file
> mayb be many gigabytes. If enough of these are generated concurrently,
> writing these large files may bring down a server.

Finally, someone taking a closer look at signals !

> Signal handlers are registered per child in module RINIT since SAPIs like
> Apache may register their signal handlers after MINIT. Information about the
> previous handlers is stored in a module static. I believe this will be safe
> in ZTS builds since handlers will only be registered once in a non forking
> mode. If requested I will move these into APC globals.

I'm not a great fan of sigsegv handlers. I used to maintain some code
which ignored implicit null checks & hooked onto sigsegv to generate
NullRef exceptions (ucontext to get $pc ... etc), which sort of is a
*big* pain to debug in this case.

> I've also made the patch available at the following url in case the
> attachment is problematic:
> 
> http://sizzo.org/~screen/patches/apc_signal_unmap.patch

My grand APC yak shaving is stalled due to some personal stuff, but
this bit of code makes it *really* easy for me to integrate something
else which's been pending for a long time.

http://t3.dotgnu.info/blog/php/long-lost-todo.html

As I keep telling myself these days - "It's on the roadmap" :(

Feel free to get this committed to HEAD if you wish, but I sort of
have an un-buildable mess of +/- 600-odd lines in my local build.

Cheers,
Gopal
-- 
If I learn from my mistakes, pretty soon I'll know everything