[users@httpd] CGI child processes

[Jan Eden <li...@janeden.org>]

Hi,

I am trying to get a CGI script executed via Apache. The script should call another script and exit immediately, while the second script is still running in the background.

I already tried the Perl exec and fork functions, but Apache always seems to wait for the second script to finish before displaying the "Process has been started and will run in the background" message.

When I execute the CGI script from the command line, exec works as expected (i.e. the shell returns to the prompt immediately).

How can I get Apache to disregard the process started by the CGI?

Thanks,

Jan
-- 
There are two major products that come out of Berkeley: LSD and UNIX. We don't believe this to be a coincidence. - Jeremy S. Anderson

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Re: [users@httpd] CGI child processes

[Joshua Slive <js...@gmail.com>]

On Tue, 22 Mar 2005 10:04:03 +0100, Jan Eden <li...@janeden.org> wrote:
> Scott Gifford wrote on 16.03.2005:
> 
> >Jan Eden <li...@janeden.org> writes:
> >
> >> I am trying to get a CGI script executed via Apache. The script
> >>should call another script and exit immediately, while the second
> >>script is still running in the background.
> >
> >[...]
> >
> >> How can I get Apache to disregard the process started by the CGI?
> >
> >I believe you need to fork twice, so that the long-running process is
> >a child of init (not a child of Apache).  Something like (untested):
> >
> Hi Scott,
> 
> thanks for your hint. Unfortunately, double forking also does not help. Apache still waits for the long-running process to complete.

See:
http://www.webthing.com/tutorials/cgifaq.3.html#8

Joshua.

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Re: [users@httpd] CGI child processes

[Jan Eden <li...@janeden.org>]

Scott Gifford wrote on 16.03.2005:

>Jan Eden <li...@janeden.org> writes:
>
>> I am trying to get a CGI script executed via Apache. The script
>>should call another script and exit immediately, while the second
>>script is still running in the background.
>
>[...]
>
>> How can I get Apache to disregard the process started by the CGI?
>
>I believe you need to fork twice, so that the long-running process is
>a child of init (not a child of Apache).  Something like (untested):
>
Hi Scott,

thanks for your hint. Unfortunately, double forking also does not help. Apache still waits for the long-running process to complete.

Best,

Jan
-- 
There are 10 kinds of people:  those who understand binary, and those who don't

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Re: [users@httpd] CGI child processes

[Scott Gifford <sg...@suspectclass.com>]

Jan Eden <li...@janeden.org> writes:

> I am trying to get a CGI script executed via Apache. The script
>should call another script and exit immediately, while the second
>script is still running in the background.

[...]

> How can I get Apache to disregard the process started by the CGI?

I believe you need to fork twice, so that the long-running process is
a child of init (not a child of Apache).  Something like (untested):

  if (!defined(my $f1 = fork()))
  {
    die "fork failed: $!\n";
  }
  elsif ($f1)
  {
    # Parent
    exit(0);
  }
  elsif (!defined(my $f2 = fork()))
  {
    die "second fork failed: $!\n";
  }
  elsif ($f2)
  {
    # Child
    exit(0);
  }
  else
  {
    # Grandchild
    exec(...);
  }

----ScottG.

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