- Initial import

git-svn-id: https://fail2ban.svn.sourceforge.net/svnroot/fail2ban/branches/FAIL2BAN-0_5@120 a942ae1a-1317-0410-a47c-b1dcaea8d605

utils/process.py

@@ -0,0 +1,158 @@
+# This file is part of Fail2Ban.
+#
+# Fail2Ban 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.
+#
+# Fail2Ban 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 Fail2Ban; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+# Author: Cyril Jaquier
+# 
+# $Revision$
+
+__author__ = "Cyril Jaquier"
+__version__ = "$Revision$"
+__date__ = "$Date$"
+__copyright__ = "Copyright (c) 2004 Cyril Jaquier"
+__license__ = "GPL"
+
+import os, log4py, signal
+
+# Gets the instance of log4py.
+logSys = log4py.Logger().get_instance()
+
+def createDaemon():
+	"""Detach a process from the controlling terminal and run it in the
+	background as a daemon.
+	
+	http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/278731
+	"""
+
+	try:
+		# Fork a child process so the parent can exit.  This will return control
+		# to the command line or shell.  This is required so that the new process
+		# is guaranteed not to be a process group leader.  We have this guarantee
+		# because the process GID of the parent is inherited by the child, but
+		# the child gets a new PID, making it impossible for its PID to equal its
+		# PGID.
+		pid = os.fork()
+	except OSError, e:
+		return((e.errno, e.strerror))	 # ERROR (return a tuple)
+
+	if (pid == 0):	   # The first child.
+
+		# Next we call os.setsid() to become the session leader of this new
+		# session.  The process also becomes the process group leader of the
+		# new process group.  Since a controlling terminal is associated with a
+		# session, and this new session has not yet acquired a controlling
+		# terminal our process now has no controlling terminal.  This shouldn't
+		# fail, since we're guaranteed that the child is not a process group
+		# leader.
+		os.setsid()
+	
+		# When the first child terminates, all processes in the second child
+		# are sent a SIGHUP, so it's ignored.
+		signal.signal(signal.SIGHUP, signal.SIG_IGN)
+	
+		try:
+			# Fork a second child to prevent zombies.  Since the first child is
+			# a session leader without a controlling terminal, it's possible for
+			# it to acquire one by opening a terminal in the future.  This second
+			# fork guarantees that the child is no longer a session leader, thus
+			# preventing the daemon from ever acquiring a controlling terminal.
+			pid = os.fork()		# Fork a second child.
+		except OSError, e:
+			return((e.errno, e.strerror))  # ERROR (return a tuple)
+	
+		if (pid == 0):	  # The second child.
+			# Ensure that the daemon doesn't keep any directory in use.  Failure
+			# to do this could make a filesystem unmountable.
+			os.chdir("/")
+			# Give the child complete control over permissions.
+			os.umask(0)
+		else:
+			os._exit(0)	  # Exit parent (the first child) of the second child.
+	else:
+		os._exit(0)		 # Exit parent of the first child.
+
+	# Close all open files.  Try the system configuration variable, SC_OPEN_MAX,
+	# for the maximum number of open files to close.  If it doesn't exist, use
+	# the default value (configurable).
+	try:
+		maxfd = os.sysconf("SC_OPEN_MAX")
+	except (AttributeError, ValueError):
+		maxfd = 256	   # default maximum
+
+	for fd in range(0, maxfd):
+		try:
+			os.close(fd)
+		except OSError:   # ERROR (ignore)
+			pass
+
+	# Redirect the standard file descriptors to /dev/null.
+   	os.open("/dev/null", os.O_RDONLY)	# standard input (0)
+	os.open("/dev/null", os.O_RDWR)		# standard output (1)
+	os.open("/dev/null", os.O_RDWR)		# standard error (2)
+
+	return True
+	
+def checkForPID(lockfile):
+	""" Checks for running Fail2Ban.
+	
+		Returns the current PID if Fail2Ban is running or False
+		if no instance found.
+	"""
+	try:
+		fileHandler = open(lockfile)
+		pid = fileHandler.readline()
+		return pid
+	except IOError:
+		return False
+		
+def createPID(lockfile):
+	""" Creates a PID lock file with the current PID.
+	"""
+	fileHandler = open(lockfile, mode='w')
+	pid = os.getpid()
+	fileHandler.write(`pid`+'\n')
+	fileHandler.close()
+	logSys.debug("Created PID lock ("+`pid`+") in "+lockfile)
+		
+def removePID(lockfile):
+	""" Remove PID lock.
+	"""
+	os.remove(lockfile)
+	logSys.debug("Removed PID lock "+lockfile)
+
+def killPID(pid):
+	""" Kills the process with the given PID using the
+		INT signal (same effect as <ctrl>+<c>).
+	"""
+	try:
+		return os.kill(pid, 2)
+	except OSError:
+		logSys.error("Can not kill process " + `pid` + ". Please check that " +
+					"Fail2Ban is not running and remove the file " +
+					"'/tmp/fail2ban.pid'")
+		return False
+
+def executeCmd(cmd, debug):
+	""" Executes an OS command.
+	"""
+	if cmd == "":
+		logSys.debug("Nothing to do")
+		return None
+	
+	logSys.debug(cmd)
+	if not debug:
+		return os.system(cmd)
+	else:
+		return None