#
# executil.py - subprocess execution utility functions
#
# Copyright (C) 1999-2011
# Red Hat, Inc. All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
# Author(s): Erik Troan <ewt@redhat.com>
#
import os, sys
import subprocess
import time
import threading
import logging
log = logging.getLogger("pylorax")
program_log = logging.getLogger("program")
[docs]class ExecProduct(object):
def __init__(self, rc, stdout, stderr):
self.rc = rc
self.stdout = stdout
self.stderr = stderr
[docs]class tee(threading.Thread):
""" Python reimplementation of the shell tee process, so we can
feed the pipe output into two places at the same time
"""
def __init__(self, inputdesc, outputdesc, logmethod, command):
threading.Thread.__init__(self)
self.inputdesc = os.fdopen(inputdesc, "r")
self.outputdesc = outputdesc
self.logmethod = logmethod
self.running = True
self.command = command
[docs] def run(self):
while self.running:
try:
data = self.inputdesc.readline()
except IOError:
self.logmethod("Can't read from pipe during a call to %s. "
"(program terminated suddenly?)" % self.command)
break
if data == "":
self.running = False
else:
self.logmethod(data.rstrip('\n'))
os.write(self.outputdesc, data)
[docs] def stop(self):
self.running = False
return self
[docs]def execWithRedirect(command, argv, stdin = None, stdout = None,
stderr = None, root = None, preexec_fn=None, cwd=None,
raise_err=False, callback_func=None, callback_args=None):
""" Run an external program and redirect the output to a file.
@param command The command to run.
@param argv A list of arguments.
@param stdin The file descriptor to read stdin from.
@param stdout The file descriptor to redirect stdout to.
@param stderr The file descriptor to redirect stderr to.
@param root The directory to chroot to before running command.
@param preexec_fn function to pass to Popen
@param cwd working directory to pass to Popen
@param raise_err raise CalledProcessError when the returncode is not 0
@return The return code of command.
"""
def chroot ():
os.chroot(root)
stdinclose = stdoutclose = stderrclose = lambda : None
argv = list(argv)
if isinstance(stdin, str):
if os.access(stdin, os.R_OK):
stdin = os.open(stdin, os.O_RDONLY)
stdinclose = lambda : os.close(stdin)
else:
stdin = sys.stdin.fileno()
elif isinstance(stdin, int):
pass
elif stdin is None or not isinstance(stdin, file):
stdin = sys.stdin.fileno()
if isinstance(stdout, str):
stdout = os.open(stdout, os.O_RDWR|os.O_CREAT)
stdoutclose = lambda : os.close(stdout)
elif isinstance(stdout, int):
pass
elif stdout is None or not isinstance(stdout, file):
stdout = sys.stdout.fileno()
if isinstance(stderr, str):
stderr = os.open(stderr, os.O_RDWR|os.O_CREAT)
stderrclose = lambda : os.close(stderr)
elif isinstance(stderr, int):
pass
elif stderr is None or not isinstance(stderr, file):
stderr = sys.stderr.fileno()
program_log.info("Running... %s", " ".join([command] + argv))
#prepare os pipes for feeding tee proceses
pstdout, pstdin = os.pipe()
perrout, perrin = os.pipe()
env = os.environ.copy()
env.update({"LC_ALL": "C"})
if root:
preexec_fn = chroot
cwd = root
program_log.info("chrooting into %s", cwd)
elif cwd:
program_log.info("chdiring into %s", cwd)
try:
#prepare tee proceses
proc_std = tee(pstdout, stdout, program_log.info, command)
proc_err = tee(perrout, stderr, program_log.error, command)
#start monitoring the outputs
proc_std.start()
proc_err.start()
proc = subprocess.Popen([command] + argv, stdin=stdin,
stdout=pstdin,
stderr=perrin,
preexec_fn=preexec_fn, cwd=cwd,
env=env)
# Wait for the process to finish, calling callback_func to test for early termination
while proc.returncode is None:
time.sleep(5)
if callback_func and callback_func():
proc.terminate()
callback_func = None
proc.poll()
ret = proc.returncode
#close the input ends of pipes so we get EOF in the tee processes
os.close(pstdin)
os.close(perrin)
#wait for the output to be written and destroy them
proc_std.join()
del proc_std
proc_err.join()
del proc_err
stdinclose()
stdoutclose()
stderrclose()
except OSError as e:
errstr = "Error running %s: %s" % (command, e.strerror)
log.error(errstr)
program_log.error(errstr)
#close the input ends of pipes so we get EOF in the tee processes
os.close(pstdin)
os.close(perrin)
proc_std.join()
proc_err.join()
stdinclose()
stdoutclose()
stderrclose()
raise RuntimeError, errstr
if ret and raise_err:
raise subprocess.CalledProcessError(ret, [command]+argv)
return ret
[docs]def execWithCapture(command, argv, stdin = None, stderr = None, root=None,
preexec_fn=None, cwd=None, raise_err=False):
""" Run an external program and capture standard out.
@param command The command to run.
@param argv A list of arguments.
@param stdin The file descriptor to read stdin from.
@param stderr The file descriptor to redirect stderr to.
@param root The directory to chroot to before running command.
@param preexec_fn function to pass to Popen
@param cwd working directory to pass to Popen
@param raise_err raise CalledProcessError when the returncode is not 0
@return The output of command from stdout.
"""
def chroot():
os.chroot(root)
def closefds ():
stdinclose()
stderrclose()
stdinclose = stderrclose = lambda : None
rc = ""
argv = list(argv)
if isinstance(stdin, str):
if os.access(stdin, os.R_OK):
stdin = os.open(stdin, os.O_RDONLY)
stdinclose = lambda : os.close(stdin)
else:
stdin = sys.stdin.fileno()
elif isinstance(stdin, int):
pass
elif stdin is None or not isinstance(stdin, file):
stdin = sys.stdin.fileno()
if isinstance(stderr, str):
stderr = os.open(stderr, os.O_RDWR|os.O_CREAT)
stderrclose = lambda : os.close(stderr)
elif isinstance(stderr, int):
pass
elif stderr is None or not isinstance(stderr, file):
stderr = sys.stderr.fileno()
program_log.info("Running... %s", " ".join([command] + argv))
env = os.environ.copy()
env.update({"LC_ALL": "C"})
if root:
preexec_fn = chroot
cwd = root
program_log.info("chrooting into %s", cwd)
elif cwd:
program_log.info("chdiring into %s", cwd)
try:
proc = subprocess.Popen([command] + argv, stdin=stdin,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
preexec_fn=preexec_fn, cwd=cwd,
env=env)
while True:
(outStr, errStr) = proc.communicate()
if outStr:
map(program_log.info, outStr.splitlines())
rc += outStr
if errStr:
map(program_log.error, errStr.splitlines())
os.write(stderr, errStr)
if proc.returncode is not None:
break
except OSError as e:
log.error ("Error running " + command + ": " + e.strerror)
closefds()
raise RuntimeError, "Error running " + command + ": " + e.strerror
closefds()
if proc.returncode and raise_err:
raise subprocess.CalledProcessError(proc.returncode, [command]+argv)
return rc
[docs]def execWithCallback(command, argv, stdin = None, stdout = None,
stderr = None, echo = True, callback = None,
callback_data = None, root = '/'):
def closefds ():
stdinclose()
stdoutclose()
stderrclose()
stdinclose = stdoutclose = stderrclose = lambda : None
argv = list(argv)
if isinstance(stdin, str):
if os.access(stdin, os.R_OK):
stdin = os.open(stdin, os.O_RDONLY)
stdinclose = lambda : os.close(stdin)
else:
stdin = sys.stdin.fileno()
elif isinstance(stdin, int):
pass
elif stdin is None or not isinstance(stdin, file):
stdin = sys.stdin.fileno()
if isinstance(stdout, str):
stdout = os.open(stdout, os.O_RDWR|os.O_CREAT)
stdoutclose = lambda : os.close(stdout)
elif isinstance(stdout, int):
pass
elif stdout is None or not isinstance(stdout, file):
stdout = sys.stdout.fileno()
if isinstance(stderr, str):
stderr = os.open(stderr, os.O_RDWR|os.O_CREAT)
stderrclose = lambda : os.close(stderr)
elif isinstance(stderr, int):
pass
elif stderr is None or not isinstance(stderr, file):
stderr = sys.stderr.fileno()
program_log.info("Running... %s", " ".join([command] + argv))
p = os.pipe()
p_stderr = os.pipe()
childpid = os.fork()
if not childpid:
os.close(p[0])
os.close(p_stderr[0])
os.dup2(p[1], 1)
os.dup2(p_stderr[1], 2)
os.dup2(stdin, 0)
os.close(stdin)
os.close(p[1])
os.close(p_stderr[1])
os.execvp(command, [command] + argv)
os._exit(1)
os.close(p[1])
os.close(p_stderr[1])
log_output = ''
while 1:
try:
s = os.read(p[0], 1)
except OSError as e:
if e.errno != 4:
map(program_log.info, log_output.splitlines())
raise IOError, e.args
if echo:
os.write(stdout, s)
log_output += s
if callback:
callback(s, callback_data=callback_data)
# break out early if the sub-process changes status.
# no need to flush the stream if the process has exited
try:
(pid, status) = os.waitpid(childpid,os.WNOHANG)
if pid != 0:
break
except OSError as e:
log.critical("exception from waitpid: %s %s", e.errno, e.strerror)
if len(s) < 1:
break
map(program_log.info, log_output.splitlines())
log_errors = ''
while 1:
try:
err = os.read(p_stderr[0], 128)
except OSError as e:
if e.errno != 4:
map(program_log.error, log_errors.splitlines())
raise IOError, e.args
break
log_errors += err
if len(err) < 1:
break
os.write(stderr, log_errors)
map(program_log.error, log_errors.splitlines())
os.close(p[0])
os.close(p_stderr[0])
try:
#if we didn't already get our child's exit status above, do so now.
if not pid:
(pid, status) = os.waitpid(childpid, 0)
except OSError as e:
log.critical("exception from waitpid: %s %s", e.errno, e.strerror)
closefds()
rc = 1
if os.WIFEXITED(status):
rc = os.WEXITSTATUS(status)
return ExecProduct(rc, log_output , log_errors)
def _pulseProgressCallback(data, callback_data=None):
if callback_data:
callback_data.pulse()
[docs]def execWithPulseProgress(command, argv, stdin = None, stdout = None,
stderr = None, echo = True, progress = None,
root = '/'):
return execWithCallback(command, argv, stdin=stdin, stdout=stdout,
stderr=stderr, echo=echo, callback=_pulseProgressCallback,
callback_data=progress, root=root)
## Run a shell.
[docs]def execConsole():
try:
proc = subprocess.Popen(["/bin/sh"])
proc.wait()
except OSError as e:
raise RuntimeError, "Error running /bin/sh: " + e.strerror
[docs]def runcmd(cmd, **kwargs):
""" run execWithRedirect with raise_err=True
"""
kwargs["raise_err"] = True
return execWithRedirect(cmd[0], cmd[1:], **kwargs)
[docs]def runcmd_output(cmd, **kwargs):
""" run execWithCapture with raise_err=True
"""
kwargs["raise_err"] = True
return execWithCapture(cmd[0], cmd[1:], **kwargs)