Anonymous Pipes (Was do anonymous pipes normally work on NT?)

[Florent Heyworth]

Hi

looking at the test scripts Georg Mischler provided it seems the code is
failing
to pass on the standard handles to the created process. The following
method works:

file runproc.py
---------------

'''runproc.py

start a process with three inherited pipes.
Try to write to and read from those.
'''

import win32api
import win32pipe
import win32file
import win32process
import win32security
import win32event
import os

#Constants for stdandard handles
STD_ERR_HANDLE=-12
STD_OUTPUT_HANDLE=-11
STD_INPUT_HANDLE=-10

class Process:
    def run(self, cmdline):

        # security attributes for pipes
        sAttrs = win32security.SECURITY_ATTRIBUTES()
        sAttrs.bInheritHandle = 1

        # create pipes
        hStdin_r,self.hStdin_w=win32pipe.CreatePipe(sAttrs, 0)
        self.hStdout_r,hStdout_w=win32pipe.CreatePipe(sAttrs,0)
        self.hStderr_r,hStderr_w=win32pipe.CreatePipe(sAttrs, 0)

        #associate Standard output to previously open handle
        win32api.SetStdHandle(STD_OUTPUT_HANDLE,hStdout_w)

        # set the info structure for the new process.
        StartupInfo = win32process.STARTUPINFO()

        # start the process.
        hProcess, hThread, dwPid, dwTid=win32process.CreateProcess(
                None, #program
                cmdline,# command line
                sAttrs,  # process security attributes
                sAttrs,  # thread attributes
                1,      # inherit handles,
                win32process.NORMAL_PRIORITY_CLASS,
                None,  # no new environment
                None,  # current directory (stay where we are)
                StartupInfo)
        # normally, we would save the pid etc. here...


        res, str = win32file.ReadFile(self.hStdout_r,100)
        if res == 0: print 'read:', str
        else: 'read nothing.'


if __name__ == '__main__':
    p = Process()
    p.run('..\\python.exe testpipe.py')
-----------------
end of runproc.py

file testpipe.py - explicit assignement of standard handles
----------------
import win32api
import win32file

STD_ERR_HANDLE=-12
STD_OUTPUT_HANDLE=-11
STD_INPUT_HANDLE=-10

std_in=win32api.GetStdHandle(STD_INPUT_HANDLE)
std_err=win32api.GetStdHandle(STD_ERR_HANDLE)
std_out=win32api.GetStdHandle(STD_OUTPUT_HANDLE)

win32file.WriteFile(std_out, 'this method works....')

end of testpipe.py
------------------

file testpipe1.py implicit standard handles
------------------
print "this method works as well..."

end of testpipe1.py
-----------------

Cheers

Florent Heyworth