Lib/popen2.py

   1 import os
   2 import sys
   3 import string
   4
   5 MAXFD = 100     # Max number of file descriptors (os.getdtablesize()???)
   6
   7 def popen2(cmd):
   8         cmd = string.split(cmd)
   9         p2cread, p2cwrite = os.pipe()
  10         c2pread, c2pwrite = os.pipe()
  11         pid = os.fork()
  12         if pid == 0:
  13                 # Child
  14                 os.close(0)
  15                 os.close(1)
  16                 if os.dup(p2cread) <> 0:
  17                         sys.stderr.write('popen2: bad read dup\n')
  18                 if os.dup(c2pwrite) <> 1:
  19                         sys.stderr.write('popen2: bad write dup\n')
  20                 for i in range(3, MAXFD):
  21                         try:
  22                                 os.close(i)
  23                         except:
  24                                 pass
  25                 try:
  26                         os.execv(cmd[0], cmd)
  27                 finally:
  28                         os._exit(1)
  29                 # Shouldn't come here, I guess
  30                 os._exit(1)
  31         os.close(p2cread)
  32         tochild = os.fdopen(p2cwrite, 'w')
  33         os.close(c2pwrite)
  34         fromchild = os.fdopen(c2pread, 'r')
  35         return fromchild, tochild