#!/usr/bin/env perl

# --------------------------------------------------
#  update-internaldomains - atomically update global
#                           whitelist of internal
#                           domains
#                               
#  Author                 - Jesse D. Guardiani
#  Created                - 03/12/03
#  Modified               - 03/18/03
# --------------------------------------------------
# See 'update-internaldomains -h' for Usage
# instructions.
#         
#  ChangeLog
#  ---------
#
#  03/18/03 - JDG
#  --------------
#  - Added Usage text above.
#  - Made a few clarifications to the Usage() text
#  - Added the -a option
#  - Added Copyright and GNU statement
#
#  03/12/03 - JDG
#  --------------
#  - Created
# --------------------------------------------------
# Copyright (C) 2003 Jesse D. Guardiani <jesse@wingnet.net>
#
# This file is part of TMDA.
#
# TMDA 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.  A copy of this license should
# be included in the file COPYING.
#
# TMDA 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 TMDA; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
# --------------------------------------------------


use strict;

# -----------------------------------
# GLOBALS
# -----------------------------------

my $VERSION="0.001";         # Version number of this script
my $debug=0;                 # We default to non-debug mode
my $path_to_whitelist="";    # Path (relative or full) to whitelist
my $do_combine=0;            # boolean flag that specifies whether or not the output of $command should
                             # be combined with the contents of the file specified by -a
my $add_to_whitelist="addto-whitelist";
                             # Name of the file whos contents will be combined with $command's output
			     # if the file "$base_whitelist_dir/$add_to_whitelist" exists.
my $command="";              # Command to execute that will return a list of internal domains, one per line.
my $base_whitelist_dir="";   # Path to the whitelist's base directory, without a trailing slash.
my $tmp_file="";             # relative or full path to temporary file
my $owner="vpopmail";        # file owner. This is a candidate for a command line option someday.        
my $last_error="";           # Last Error code returned by back-tick called shell command




# -----------------------------------
# usage() function
# -----------------------------------

sub usage()
{
	print STDERR << "EOF";

------------------------------------------------------------------------
usage:  update-internaldomains [-dh] [-a combine-file]
                               -f whitelist -s command
------------------------------------------------------------------------
  Version: $VERSION

  Summary:
           update-internaldomains is intended to be run from cron every
           fifteen minutes or so. -f and -s are required options. This
	   script was originally written to retrieve a list of domains
	   from vpopmail's 'vdominfo -n' command. However, it can be
           used with ANY command that returns a list of domains in the
	   correct format (See -s syntax below).

           Possible -s commands might include: Billing apps, database
           retrieval scripts, radius query scripts, etc...

  How it works:	   
           update-internaldomains executes the command specified by -s
           and saves it's output to a temporary file in the same
           directory as the file specified by -f.

           update-internaldomains then compares the whitelist specified
           by -f with the temp file it just created using 'diff -q'. If
           changes are found, update-internaldomains atomically replaces
           the whitelist specified by -f with the temporary file using 
           'mv'.

           NOTE: The 'mv' operation is only atomic if your system has
                 a POSIX rename() function, and the 'mv' command makes
                 use of it to overwrite single files.

  Command Line Options:

  -a combine-file
           If specified, combine-file is the full path to a flat file
           containing domain names, one per line, which you wish to
           COMBINE with the output of '-s command' BEFORE comparing
           and/or updating the whitelist specified by -f.

  -d       debug mode.

  -f whitelist
           This is the path to the whitelist you wish to write your 
           internal domain list to.

  -s command
           command you wish to run that will return a raw list of
           domains, one per line, in the following format:

	   domain1.com
	   domain2.com
	   domain3.org
	   etc...

  -h       print this usage report.

  Example: 

  update-internaldomains -f "/usr/local/vpopmail/.tmda/internaldomains" -s "/usr/local/vpopmail/bin/vdominfo -n"

  Return Codes:
           If update-internaldomains can not write to the directory in 
           which the file specified by -f resides, it exits nonzero.

           If update-internaldomains can not execute the command
           specified by -s, it immediately exits nonzero.

           If the 'mv' fails, update-internaldomains immediately exits
           nonzero.

           If anything else that update-internaldomains tries to execute
           fails, update-internaldomains will immediately exit nonzero.
------------------------------------------------------------------------\n

EOF
}






# -----------------------------------
# General Functions
# -----------------------------------

# save the last exit status
sub saveexitstatus()
{
	# Get exit status from last command.
	$last_error = $? >> 8;
}

# Get the last exit status
sub getexitstatus()
{
	# return exit status from last command.
	return $last_error;
}

# Print error message if bad exit status
sub dieifbadexit( $$ )
{
	my $badstatus=$_[0];  # the "bad" exit status
	my $message=$_[1];    # the message to print before exiting if the last exit status was "bad"

	# Check exit status.
	if ( getexitstatus() == $badstatus and getexitstatus() ne "") {
		print STDERR ($message);
		exit 1;
	}
}

# Print error message if bad exit status
sub dieifnotgoodexit( $$ )
{
	my $goodstatus=$_[0]; # the "good" exit status
	my $message=$_[1];    # the message to print before exiting if the last exit status was not the "good" exit status

	# Check exit status.
	if ( getexitstatus() != $goodstatus and getexitstatus() ne "") {
		print STDERR ($message);
		exit 1;
	}
}

# If debugging is turned on, print the message
sub ifdebugprint( $ )
{
	my $message=$_[0]; # the message to print
	# print debug info
	if ($debug) {
		print STDERR ($message);
	}
}




# -----------------------------------
# Handle command line arguments
# -----------------------------------

# Import Getopt::Std module
use Getopt::Std;

# we only take one option: -f
# -f has a single argument.
my $opt_string = 'hda:f:s:';

# get command line flags. If we recieve none, then we attempt to use defaults.
getopts( "$opt_string", \my %opt );

# print usage message if -h specified
usage() and exit if $opt{h};

# setup debug mode
$debug = 1 if $opt{d};
print STDERR "Debugging mode ON.\n" if $debug;

# set appropriate variables associated with -a
if ($opt{a}) {
	# if flat file does not exist, create it
	if ( ! -e $opt{a} ) {
		`touch "$opt{a}"`;

		# Get any bad exit status from 'rm'.
		saveexitstatus();

		# Check exit status.
		dieifnotgoodexit(0, "\nError: 'touch \"$opt{a}\"' failed!\n");

		# This code is only executed if the flat file was successfully created.
		ifdebugprint("whitelist created: $opt{a}\n");
	}
	
	die "$opt{a} is not readable." unless (-r $opt{a});

	$add_to_whitelist="$opt{a}";
	$do_combine=1;
}

# print debug info
ifdebugprint("\$add_to_whitelist=$add_to_whitelist\n");
ifdebugprint("\$do_combine=$do_combine\n");


# do checks on whitelist file and set $path_to_whitelist variable
if ($opt{f}) {
	if ($opt{f} == 1) {
		die "\n -f requires an argument.";
	}

	# if whitelist does not exist, create it
	if ( ! -e $opt{f} ) {
		`touch "$opt{f}"`;

		# Get any bad exit status from 'rm'.
		saveexitstatus();

		# Check exit status.
		dieifnotgoodexit(0, "\nError: 'touch \"$opt{f}\"' failed!\n");

		# This code is only executed if the whitelist file was successfully created.
		ifdebugprint("whitelist created: $opt{f}\n");
	}
	
	die "$opt{f} is not readable and writable." unless (-r $opt{f} and -w $opt{f});

	$path_to_whitelist="$opt{f}";

	# print debug info
	ifdebugprint("\$path_to_whitelist=$path_to_whitelist\n");
} else {
	usage();
	exit 1;
}

# do checks on command file and set $command variable
if ($opt{s}) {
	if ($opt{s} == 1) {
		die "\n -s requires an argument.";
	}
	
#	die "$opt{s} is not executable." unless (-x $opt{s});

	$command="$opt{s}";

	# print debug info
	ifdebugprint("\$command=$command\n");
} else {
	usage();
	exit 1;
}


# -----------------------------------
# Parse $path_to_whitelist for
# directory path.
# -----------------------------------

# get directory that whitelist lives in, then set $tmp_file variable
my $last_slash_loc = rindex ("$path_to_whitelist","/");

# if $path_to_whitelist contains JUST a filename and no path
if ($last_slash_loc == -1) {
	$base_whitelist_dir = ".";
} else {
	$base_whitelist_dir = substr ("$path_to_whitelist", 0, $last_slash_loc);
}

# build temp file path.
$tmp_file = $base_whitelist_dir . "/tmp";


# print debug info
ifdebugprint("\$tmp_file=$tmp_file\n");




# -----------------------------------
# Get command output
# -----------------------------------

# remove temp file if it exists
if ( -e "$tmp_file" ) {
	# print debug info
	ifdebugprint("'$tmp_file' exists.\n");

	`rm "$tmp_file"`;

	saveexitstatus();
	dieifnotgoodexit(0, "\"rm '$tmp_file'\" failed!");

	# print debug info
	ifdebugprint("\"rm '$tmp_file'\" successful!\n");
}

# Get any bad exit status from 'rm'.
saveexitstatus();

# Check exit status.
dieifnotgoodexit(0, "\nError: 'rm' failed to remove temp file!\n");

if ( -r "$add_to_whitelist" and $do_combine) {
	# define the string we wish to execute
	my $execstring="$command | cat - \"$add_to_whitelist\" | sort | uniq > \"$tmp_file\"";
	
	# execute our command pipe.
	`$execstring`;

	# Get any bad exit status from execution.
	saveexitstatus();

	# Check exit status and print error and exit if bad exit status found.
	dieifnotgoodexit(0, "\nError: `$execstring` failed!\n");
} else {
	# define the string we wish to execute
	my $execstring="$command | sort | uniq > \"$tmp_file\"";

	# execute our command pipe.
	`$execstring`;

	# Get any bad exit status from execution.
	saveexitstatus();

	# Check exit status.
	dieifnotgoodexit(0, "\nError: `$execstring` failed!\n");
}




# -----------------------------------
# Use 'diff -q' to compare the
# contents of our temp file with the
# contents of $path_to_whitelist
# -----------------------------------

`diff -q "$tmp_file" "$path_to_whitelist"`;

# Get any bad exit status from execution.
saveexitstatus();

#If 'diff -q' returns with an 'exit 2', then there has been an error.
dieifbadexit(2, "\nError: \"diff -q '$tmp_file' '$path_to_whitelist'\" failed!\n");



# -----------------------------------
# If the contents differ, then
# atomically update $path_to_whitelist
# Otherwise, simply 'exit 0;'
# -----------------------------------

#If 'diff -q' returns with an 'exit 1', the files do NOT match.
if ( getexitstatus() == 1 and getexitstatus() ne "") {
	# atomically overwrite $path_to_whitelist with $tmp_file
	`mv '$tmp_file' '$path_to_whitelist'`;

	# Get any bad exit status from execution.
	saveexitstatus();

	#If 'mv' returns nonzero, there was an error
	dieifnotgoodexit(0, "\nError: \"mv '$tmp_file' '$path_to_whitelist'\" failed!\n");
	
	# This point is only reached if 'mv' succeeded
	ifdebugprint("\"mv '$tmp_file' '$path_to_whitelist'\" successful!\n");
} else {
	# print debug info
	ifdebugprint("\"diff -q '$tmp_file' '$path_to_whitelist'\" indicates no update is necessary!\n");
}



# -----------------------------------
# Make sure the files we just touched
# are owned by $owner
# -----------------------------------

ifdebugprint("executing 'chown $owner \"$base_whitelist_dir\"/*'");

`chown $owner "$base_whitelist_dir"/*`;

saveexitstatus();
dieifnotgoodexit(0,"'chown $owner \"$base_whitelist_dir\"/*' failed!");

ifdebugprint("exiting happy.\n");

# If execution reaches this point, then chances are that all is well.
exit 0;