freeipa/ipa-client/ipaclient/ipachangeconf.py

#
# ipachangeconf - configuration filke manipulation classes and functions
# partially based on authconfig code
# Copyright (c) 1999-2007 Red Hat, Inc.
# Author: Simo Sorce <ssorce@redhat.com>
#
# This 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, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#

import fcntl
import os
import string
import time

def openLocked(filename, perms):
	fd = -1
	try:
		fd = os.open(filename, os.O_RDWR | os.O_CREAT, perms)
		
		fcntl.lockf(fd, fcntl.LOCK_EX)
	except OSError, (errno, strerr):
		if fd != -1:
			try:
				os.close(fd)
			except OSError:
				pass
		raise IOError(errno, strerr)
	return os.fdopen(fd, "r+")

class IPAChangeConf:

    def __init__(self, name):
        self.progname = name
        self.optpre = (" ",)
        self.doptpre = self.optpre[0]
        self.assign = ("=",)
        self.dassign = self.assign[0]
        self.comment = ("#",)
        self.dcomment = self.comment[0]
        self.eol = ("\n",)
        self.deol = self.eol[0]
	#self.sectdel = ("[","]")
	self.sectdel = ()

    def setProgName(self, name):
        self.progname = name

    def setOptionPrefix(self, prefix):
        self.optpre = prefix
        self.doptpre = self.optpre[0]

    def setOptionAssignment(self, assign):
        self.assign = assign
        self.dassign = self.assign[0]

    def setCommentPrefix(self, comment):
        self.comment = comment
        self.dcomment = self.comment[0]

    def setEndLine(self, eol):
        self.eol = eol
        self.deol = self.eol[0]

    def setSectionDelimiters(self, delims):
        self.sectdel = delims

    def confDump(self, options):
        output = ""

        #pre conf options delimiter
        output += self.deol
        output += self.dcomment+"["+self.progname+"]--start-line--"+self.deol
        output += self.deol
        output += self.dcomment+" Generated by authconfig on " + time.strftime("%Y/%m/%d %H:%M:%S") + self.deol
        output += self.dcomment+" DO NOT EDIT THIS SECTION (delimited by --start-line--/--end-line--)"+self.deol
        output += self.dcomment+" Any modification may be deleted or altered by authconfig in future"+self.deol
        output += self.deol

        #set options
        for opt in options:
            if opt['action'] == "set":
                output += self.doptpre+opt['name']+" "+self.dassign+" "+opt['value']+self.deol

        #post conf options delimiter
        output += self.deol
        output += self.dcomment+"["+self.progname+"]--end-line--"+self.deol
        output += self.deol

        return output

    def matchAutoEnd(self, line):
        if line.endswith("]--end-line--"):
            return True
        return False

    def matchAutoStart(self, line):
        if line.endswith("]--start-line--"):
            return True
        return False

    def matchComment(self, line):
        for v in self.comment:
            if line.strip().startswith(v):
                return True
        return False

    def matchLineOption(self, line, opt):
        parts = line.split(self.dassign, 1)
        if len(parts) < 2:
            return False
        elif parts[0].split() == opt['name'].split():
            return True
        else:
            return False

    def matchSection(self, line):
        cl = "".join(line.strip().split()).lower()
        if len(self.sectdel) != 2:
            return False
        if not cl.startswith(self.sectdel[0]):
            return False
        if not cl.endswith(self.sectdel[1]):
            return False
        return cl[len(self.sectdel[0]):-len(self.sectdel[1])]            

    def getSectionLine(self, section):
        if len(self.sectdel) != 2:
            return section
        return self.sectdel[0]+section+self.sectdel[1]+self.deol

    def checkLineOption(self, line, options):
        output = ""

        # Check if this is a setting we care about.
        for opt in options:
            if self.matchLineOption(line.strip(), opt):
                output = self.dcomment
                break

        output += line
        return output;

    # Write settings to configuration file
    # file is a path
    # options is a set of dictionaries in the form:
    #     [{'name': 'foo', 'value': 'bar', 'action': 'set/comment'}]
    # section is a section name like 'global'
    def changeConf(self, file, options, section=None):
        autosection = False
	savedsection = None
        done = False
        output = ""
        f = None
        try:
            f = openLocked(file, 0644)

            # Read in the old file.
            for line in f:

                if autosection:
                    if self.matchAutoEnd(line):
                        autosection = False
                    #skip all previous auto-generated lines
                    continue

                if self.matchAutoStart(line):
                    autosection = True
                    continue

                # If it's a comment, just pass it through.
                if self.matchComment(line):
                    output += line
                    continue

                # If it's a section start, note the section name.
                value = self.matchSection(line)
                if value:

                    # Here we are at start if a new section, if the previous one matches
                    # the specified section, dump here before starting the new one
                    # the comparison with section == None is intentional and matches the
                    # request to dump the options at the end of an implicit initial
                    # unmarked section before any section is started
                    if savedsection == section:
                        output += self.confDump(options)
                        done = True

                    savedsection = value
                    output += line
                    continue

                # Comment out options we care about.
                if savedsection == section:
                    output += self.checkLineOption(line, options)
                    continue

                # Copy anything else as is.
                output += line

            if not done:
                if section:
                    output += getSectionLine(section)
                output += self.confDump(options)

            # Write it out and close it.
            f.seek(0)
            f.truncate(0)
            f.write(output)
        finally:
            try:
                if f:
                    f.close()
            except IOError:
                pass
        return True