How to launch an independant and detached process?

[Olivier CARRERE]

Hello,

I've been recently 'converted' to python and I've got a problem.

I wish to write a remote process manager wich can
start/stop/kill/query/info a bunch of processes.

I use Debian 2.2 GNU/Linux with python 1.5.2 with most library (Debian)
packages installed.

I've allready written and tested a multithreaded socket server wich can
handle all queries from clients, but I have  difficulties to start
processes : I wish to start them completely detached from my manager but
they don't quite seem to :)

Let me explain how I proceed : The client connects to my manager, he gets
handled by a thread, he specifies  the parameters of the controlled
process (exe name, exe params...), then he starts it. The start procedure
is handled by the run Detach functions : 

def runDetach(exeName, exeParams):
    "Runs a correctly detached process"
    rd,wr=os.pipe() # to communicate son of son's pid...
    if os.fork()==0:
        detachPid=os.fork() if detachPid==0:
            #setDaemon()
            os.execv(exeName, exeParams)
        else:
            os.write(wr,str(detachPid)) os._exit(0) # this should\
            potentially detach correctly the son process
    pid=int(os.read(rd,5)) os.wait() os.close(rd) os.close(wr) return pid

The set Daemon function should be able to separate my process from its
process group...

def setDaemon(path="/"):
    """Set current executable as a deamon in the given path.
    Horrible C-like function."""
    # Close all file descriptors
    i=0 while 1:
        try:
            print os.fstat(i)
        except OSError:
            break # Mmmmh, no more opened descriptor (maybe more after,\
            but how can we know with this python release?)
        os.close(i) i=i+1
    # Set as no affiliated TTY...
    myTTY=os.open("/dev/tty",os.O_RDWR) fcntl.ioctl(myTTY,IOCTL.TIOCNOTTY,\
    0) os.close(myTTY)
    # Change current path
    os.chdir(path)
    # Set the default group to none (independant)
    os.setpgrp()
    # Link the stdin, stdout, stderr to null
    fd=os.open("/dev/null", os.O_RDWR) os.dup(fd) os.dup(fd)

Here are my problems :

 - the setDeamon doesn't seem to work (my exe cannot be execved once it
 has been launched).
 - I can't close my client network socket after I launched runDetach() (my
 client thread stays frozen into socket.close() ) !
 - Is it the right way to detach a process ? (Maybe it's a more general
 programmation issue)

Thanks all for your help,

- Olivier