I am trying to run a shell command from a mod_perl2 response handler.
It works properly for some number of HTTP requests, but sometimes it
fails (somewhat randomly) and I see in my Apache2 error log that one of
the Apache2 child processes has died with a segmentation fault.
For example, /var/log/apache2/error.log shows:
[Tue Jan 03 12:16:10 2012] [notice] child pid 3538 exit signal Segmentation
fault (11)
Is this normal? How does one normally run a shell command from a
response handler? I do not want to return the command's output to the
client.
Here is a trivial example response handler that exhibits this behavior:
sub handler
{
my $r = shift || die;
my $f = $ENV{DOCUMENT_ROOT} . "/date.txt";
system("date >> $f");
$r->internal_redirect("/date.txt");
return Apache2::Const::OK;
}
Can anyone provide any guidance? Does this work for you?
Note that you may not notice the problem if you don't carefully watch
the Apache2 error log (e.g., with "tail -f /var/log/apache2/error.log"),
because Apache2 automatically spawns new children processes as needed,
and client (such as Firefox or wget, though not curl) seem to
automatically re-try the request when it fails, thus giving the illusion
of succeeding.
P.S. I have posted about this on perlmonks, but thus far have not found
a solution:
http://www.perlmonks.org/?node_id=945947
--
David Booth, Ph.D.
http://dbooth.org/
Opinions expressed herein are those of the author and do not necessarily
reflect those of his employer.
