Hi all,
Some time ago we had a thread about starting long-running background processes from mp2. I've found a race condition in our last solution. The helper background script could be killed by apache cleanup handler before it had a chance to fork into background and do "setsid". Here's the script itself:
===start=== #!/usr/bin/perl -w use strict; use warnings; use POSIX ();
chdir '/';
POSIX::setsid;
You mean you have moved the setsid call to an earlier phase? so setsid is called before spawn_proc_prog() has returned?
exit if fork() > 0; # fork once again
close STDIN;
open STDOUT, '+>>', '/path/to/apache/error_log'; # any way to get path to the current error_log and pass it in from the caller as an argument or as an opened filehandle ?
open STDERR, '>&STDOUT';
exec ( @ARGV ) or die "Failed to exec subprocess: [EMAIL PROTECTED]";
===end===
Here's an updated helper subroutine:
sub safe_exec {
my $in = $apr->spawn_proc_prog ( '/path/to/exec_helper.pl', [EMAIL PROTECTED] );
# makes us sleep until the helper is forked into background and it's handlers are untied from us
eval { read $in, my($buffer), 1024 };
if ( $@ ) {
print STDERR "exec [EMAIL PROTECTED]";
}
close $in;
}
I had to use this form of spawn_proc_prog to get something to wait on.
but in the normal case where you don't need to get anything from the sub-process the above is not needed, no?
-- __________________________________________________________________ Stas Bekman JAm_pH ------> Just Another mod_perl Hacker http://stason.org/ mod_perl Guide ---> http://perl.apache.org mailto:[EMAIL PROTECTED] http://use.perl.org http://apacheweek.com http://modperlbook.org http://apache.org http://ticketmaster.com
