#!/usr/bin/python --

## Process.py
##
## Dru Nelson <dru@egroups.com>
## 7-15-99

'''
Process.py -- an objects for manipulating unix processes


'''  # '

import os, sys, select


class Process:
    def __init__(self):
        self.stdinFd  = []
        self.stdoutFd = []
        self.stderrFd = []
        self.envDict  = None
        self.cmd = ''
        self.pid = -1
        # Default: merge stdout and stderr
        self.merge = 1
        self.fdClosed = 0


    def mergeStderr(self, i):
        if i:
            self.merge = 1
        else:
            self.merge = 0

    def markFdClosed(self):
        self.fdClosed = 1


    def pipeWrite(self):
        return self.stdinFd[1]

    def pipeRead(self):
        #print "Read fd = %s" %self.stdoutFd[0]
        return self.stdoutFd[0]

    def pipeError(self):
        return self.stderrFd[0]

    def getPid(self):
        return self.pid

    def clean(self):
        #os.close(self.stdinFd[1])
        if not self.fdClosed:
            os.close(self.stdoutFd[0])
        os.close(self.stderrFd[0])
        # Return the exit code
        return os.waitpid(self.pid, 0)[1]

    def closeAll(self, num):
        while (num < 64):
            try:
                os.close(num)
            except:
                pass
            num = num + 1

    def setEnv(self, dict):
        self.envDict = dict

    def pipe(self, command):
        self.cmd = command
        #print " Command: %s " % command

        self.stdinFd  = os.pipe()
        #print "stdin %s" %repr(self.stdinFd)

        self.stdoutFd = os.pipe()
        #print "stdout %s" %repr(self.stdoutFd)

        self.stderrFd = os.pipe()
        #print "stderr %s" %repr(self.stderrFd)

        self.pid = os.fork()
        if self.pid < 0:
            print "Error couldn't fork"
            sys.exit(1)
        if self.pid == 0:
            os.chdir('/tmp')
            # This is the child
            os.dup2(self.stdinFd[0], 0)
            os.dup2(self.stdoutFd[1], 1)
            if self.merge == 1:
                os.dup2(self.stdoutFd[1], 2)
            else:
                os.dup2(self.stderrFd[1], 2)
            self.closeAll(3)
            if self.envDict == None:
                os.execv("/bin/sh", ('sh', '-c', command))
            else:
                os.execve("/bin/sh", ('sh', '-c', command), self.envDict)
            print "Wierd"
            sys.exit(127)  # This is only reached on error
        else:
            #print "Parent child = %s " % self.pid
            os.close(self.stdinFd[0])
            os.close(self.stdinFd[1]) # close the stdin pipe
            os.close(self.stdoutFd[1])
            os.close(self.stderrFd[1])
            return self.pid;

def readDescriptor(desc):
    result = ''
    while 1:
        data = os.read(desc, 16384)
        if data == '':
            break
        result = result + data

    return result


# Return a status code and output
def doCommandWithTimeout(cmd, timeout, envDict=None):
    proc = Process()
    proc.setEnv(envDict)
    proc.pipe(cmd)
    fd = proc.pipeRead()

    x = select.select([fd], [], [], timeout)
    # timeout reached
    if ([], [], []) == x:
        os.kill(proc.getPid(), 9)
        proc.clean()
        return -1, ''

    # This has a problem - it can get hung
    # on a stuck process... need to fix
    outData = readDescriptor(fd)

    # Don't actually read the data
    i = proc.clean()
    return i, outData



# From D'Arcy J.M. Cain
def daemon(nochdir = None, noclose = None):
    """ run server as a daemon. """
    if os.fork():
        os._exit(0)

    os.setsid()
    if nochdir == None:
        os.chdir("/")
    if noclose == None:
        fp = open("/dev/null", "rw")
        sys.stdin  = sys.__stdin__  = fp
        sys.stdout = sys.__stdout__ = fp
        sys.stderr = sys.__stderr__ = fp
        del fp
    if os.fork():
        os._exit(0)