Apache and os.fork() in CGI-Binaries

[Simon Budig]

Hi all.

I am currently developing a CGI-Binary which starts a second
(long running) process. The problem is: Apache keeps the
connection open until the fork()'ed child exits.

Discussing this thing with friends we came to the conclusion
that some open filedescriptors keep the connection between the forked
child and the apache alive:

1) Apache gets a request
2) Apache starts CGI-Script (Python). This is the parent process
3) Parent process forks and creates the child
4) Parent process exits
5) Child process exits
6) Apache closes the connection to the browser.

But I need the closed connection after step 4. Since the Child
inherits all filedescriptors, this is probably the thing that 
tells apache to keep the connection open.

I tried various things:

sys.stdout.close()
sys.stdin.close()
sys.stderr.close()

then I added

sys.__stdout__.close()
sys.__stdin__.close()
sys.__stderr__.close()

and this did not help. Finally i tried:

os.close (sys.stdout.fileno ())
os.close (sys.stdin.fileno())
os.close (sys.stderr.fileno ())

But at that time the Child does not run properly to the end.
Of course I do something a la

logfile = open (mebong.basedir + "/logfile", "a")
sys.stdout = sys.stderr = logfile

immediately afterwards, but this does not help.

So - how can I release all filedescriptors inherited from the parent?

The relevant parts from my code are:

-------------------------------
# this is from the CGI-Binary
childpid = os.fork ()
if not childpid:
   os.execv ("/path/to/jobcontrol", ["jobcontrol", arg1, arg2])
-------------------------------

-------------------------------
# this is from jobcontrol
os.close (sys.stdin.fileno ())
os.close (sys.stdout.fileno ())
os.close (sys.stderr.fileno ())

logfile = open ("/path/to/logfile", "a")
sys.stdout = sys.stderr = logfile
mypid = os.getpid ()
print "%d started: %s" % (mypid, repr(sys.argv))
-------------------------------

Thanks for hints!

Bye,
        Simon

-- 
      Simon.Budig at unix-ag.org       http://www.home.unix-ag.org/simon/