viewvc-4intranet/lib/popen.py

361 lines
9.8 KiB
Python

#
# Copyright (C) 2000-2002 The ViewCVS Group. All Rights Reserved.
#
# By using this file, you agree to the terms and conditions set forth in
# the LICENSE.html file which can be found at the top level of the ViewCVS
# distribution or at http://viewcvs.sourceforge.net/license-1.html.
#
# Contact information:
# Greg Stein, PO Box 760, Palo Alto, CA, 94302
# gstein@lyra.org, http://viewcvs.sourceforge.net/
#
# -----------------------------------------------------------------------
#
# popen.py: a replacement for os.popen()
#
# This implementation of popen() provides a cmd + args calling sequence,
# rather than a system() type of convention. The shell facilities are not
# available, but that implies we can avoid worrying about shell hacks in
# the arguments.
#
# -----------------------------------------------------------------------
#
import os
import sys
import sapi
import threading
import string
if sys.platform == "win32":
import win32popen
import win32event
import win32process
import debug
import StringIO
def popen(cmd, args, mode, capture_err=1):
if sys.platform == "win32":
command = win32popen.CommandLine(cmd, args)
if mode.find('r') >= 0:
hStdIn = None
if debug.SHOW_CHILD_PROCESSES:
dbgIn, dbgOut = None, StringIO.StringIO()
handle, hStdOut = win32popen.MakeSpyPipe(0, 1, (dbgOut,))
if capture_err:
hStdErr = hStdOut
dbgErr = dbgOut
else:
dbgErr = StringIO.StringIO()
x, hStdErr = win32popen.MakeSpyPipe(None, 1, (dbgErr,))
else:
handle, hStdOut = win32popen.CreatePipe(0, 1)
if capture_err:
hStdErr = hStdOut
else:
hStdErr = win32popen.NullFile(1)
else:
if debug.SHOW_CHILD_PROCESSES:
dbgIn, dbgOut, dbgErr = StringIO.StringIO(), StringIO.StringIO(), StringIO.StringIO()
hStdIn, handle = win32popen.MakeSpyPipe(1, 0, (dbgIn,))
x, hStdOut = win32popen.MakeSpyPipe(None, 1, (dbgOut,))
x, hStdErr = win32popen.MakeSpyPipe(None, 1, (dbgErr,))
else:
hStdIn, handle = win32popen.CreatePipe(0, 1)
hStdOut = None
hStdErr = None
phandle, pid, thandle, tid = win32popen.CreateProcess(command, hStdIn, hStdOut, hStdErr)
if debug.SHOW_CHILD_PROCESSES:
debug.Process(command, dbgIn, dbgOut, dbgErr)
return _pipe(win32popen.File2FileObject(handle, mode), phandle)
# flush the stdio buffers since we are about to change the FD under them
sys.stdout.flush()
sys.stderr.flush()
r, w = os.pipe()
pid = os.fork()
if pid:
# in the parent
# close the descriptor that we don't need and return the other one.
if string.find(mode, 'r') >= 0:
os.close(w)
return _pipe(os.fdopen(r, mode), pid)
os.close(r)
return _pipe(os.fdopen(w, mode), pid)
# in the child
# we'll need /dev/null for the discarded I/O
null = os.open('/dev/null', os.O_RDWR)
if string.find(mode, 'r') >= 0:
# hook stdout/stderr to the "write" channel
os.dup2(w, 1)
# "close" stdin; the child shouldn't use it
### this isn't quite right... we may want the child to read from stdin
os.dup2(null, 0)
# what to do with errors?
if capture_err:
os.dup2(w, 2)
else:
os.dup2(null, 2)
else:
# hook stdin to the "read" channel
os.dup2(r, 0)
# "close" stdout/stderr; the child shouldn't use them
### this isn't quite right... we may want the child to write to these
os.dup2(null, 1)
os.dup2(null, 2)
# don't need these FDs any more
os.close(null)
os.close(r)
os.close(w)
# the stdin/stdout/stderr are all set up. exec the target
try:
os.execvp(cmd, (cmd,) + tuple(args))
except:
# aid debugging, if the os.execvp above fails for some reason:
print "<h2>exec failed:</h2><pre>", cmd, string.join(args), "</pre>"
raise
# crap. shouldn't be here.
sys.exit(127)
def pipe_cmds(cmds):
"""Executes a sequence of commands. The output of each command is directed to
the input of the next command. A _pipe object is returned for writing to the
first command's input. The output of the last command is directed to the
standard out. On windows, if sys.stdout is not an inheritable file handle
(i.e. it is not possible to direct the standard out of a child process to
it), then a separate thread will be spawned to spool output to
sys.stdout.write(). In all cases, the pipe_cmds() caller should refrain
from writing to the standard out until the last process has terminated.
"""
if sys.platform == "win32":
if debug.SHOW_CHILD_PROCESSES:
dbgIn = StringIO.StringIO()
hStdIn, handle = win32popen.MakeSpyPipe(1, 0, (dbgIn,))
i = 0
for cmd in cmds:
i = i + 1
dbgOut, dbgErr = StringIO.StringIO(), StringIO.StringIO()
if i < len(cmds):
nextStdIn, hStdOut = win32popen.MakeSpyPipe(1, 1, (dbgOut,))
x, hStdErr = win32popen.MakeSpyPipe(None, 1, (dbgErr,))
else:
ehandle = win32event.CreateEvent(None, 1, 0, None)
nextStdIn, hStdOut = win32popen.MakeSpyPipe(None, 1, (dbgOut, sapi.server.file()), ehandle)
x, hStdErr = win32popen.MakeSpyPipe(None, 1, (dbgErr,))
command = win32popen.CommandLine(cmd[0], cmd[1:])
phandle, pid, thandle, tid = win32popen.CreateProcess(command, hStdIn, hStdOut, hStdErr)
if debug.SHOW_CHILD_PROCESSES:
debug.Process(command, dbgIn, dbgOut, dbgErr)
dbgIn = dbgOut
hStdIn = nextStdIn
else:
hStdIn, handle = win32popen.CreatePipe(1, 0)
spool = None
i = 0
for cmd in cmds:
i = i + 1
if i < len(cmds):
nextStdIn, hStdOut = win32popen.CreatePipe(1, 1)
else:
# very last process
nextStdIn = None
if sapi.server.inheritableOut:
# send child output to standard out
hStdOut = win32popen.MakeInheritedHandle(win32popen.FileObject2File(sys.stdout),0)
ehandle = None
else:
ehandle = win32event.CreateEvent(None, 1, 0, None)
x, hStdOut = win32popen.MakeSpyPipe(None, 1, (sapi.server.file(),), ehandle)
command = win32popen.CommandLine(cmd[0], cmd[1:])
phandle, pid, thandle, tid = win32popen.CreateProcess(command, hStdIn, hStdOut, None)
hStdIn = nextStdIn
return _pipe(win32popen.File2FileObject(handle, 'wb'), phandle, ehandle)
# flush the stdio buffers since we are about to change the FD under them
sys.stdout.flush()
sys.stderr.flush()
prev_r, parent_w = os.pipe()
null = os.open('/dev/null', os.O_RDWR)
for cmd in cmds[:-1]:
r, w = os.pipe()
pid = os.fork()
if not pid:
# in the child
# hook up stdin to the "read" channel
os.dup2(prev_r, 0)
# hook up stdout to the output channel
os.dup2(w, 1)
# toss errors
os.dup2(null, 2)
# close these extra descriptors
os.close(prev_r)
os.close(parent_w)
os.close(null)
os.close(r)
os.close(w)
# time to run the command
try:
os.execvp(cmd[0], cmd)
except:
pass
sys.exit(127)
# in the parent
# we don't need these any more
os.close(prev_r)
os.close(w)
# the read channel of this pipe will feed into to the next command
prev_r = r
# no longer needed
os.close(null)
# done with most of the commands. set up the last command to write to stdout
if not sapi.server.inheritableOut:
r, w = os.pipe()
pid = os.fork()
if not pid:
# in the child (the last command)
# hook up stdin to the "read" channel
os.dup2(prev_r, 0)
if not sapi.server.inheritableOut:
os.dup2(w, 1)
os.close(r)
os.close(w)
# close these extra descriptors
os.close(prev_r)
os.close(parent_w)
# run the last command
try:
os.execvp(cmds[-1][0], cmds[-1])
except:
pass
sys.exit(127)
# not needed any more
os.close(prev_r)
if not sapi.server.inheritableOut:
os.close(w)
thread = _copy(r, sapi.server.file())
thread.start()
else:
thread = None
# write into the first pipe, wait on the final process
return _pipe(os.fdopen(parent_w, 'w'), pid, thread=thread)
class _copy(threading.Thread):
def __init__(self, srcfd, destfile):
self.srcfd = srcfd
self.destfile = destfile
threading.Thread.__init__(self)
def run(self):
try:
while 1:
s = os.read(self.srcfd, 1024)
if not s:
break
self.destfile.write(s)
finally:
os.close(self.srcfd)
class _pipe:
"Wrapper for a file which can wait() on a child process at close time."
def __init__(self, file, child_pid, done_event = None, thread = None):
self.file = file
self.child_pid = child_pid
if sys.platform == "win32":
if done_event:
self.wait_for = (child_pid, done_event)
else:
self.wait_for = (child_pid,)
else:
self.thread = thread
def eof(self):
if sys.platform == "win32":
r = win32event.WaitForMultipleObjects(self.wait_for, 1, 0)
if r == win32event.WAIT_OBJECT_0:
self.file.close()
self.file = None
return win32process.GetExitCodeProcess(self.child_pid)
return None
if self.thread and self.thread.isAlive():
return None
pid, status = os.waitpid(self.child_pid, os.WNOHANG)
if pid:
self.file.close()
self.file = None
return status
return None
def close(self):
if self.file:
self.file.close()
self.file = None
if sys.platform == "win32":
win32event.WaitForMultipleObjects(self.wait_for, 1, win32event.INFINITE)
return win32process.GetExitCodeProcess(self.child_pid)
else:
if self.thread:
self.thread.join()
return os.waitpid(self.child_pid, 0)[1]
return None
def __getattr__(self, name):
return getattr(self.file, name)
def __del__(self):
self.close()