#!/usr/bin/perl
use warnings;
use strict;

# swapfile.pl  --  Perl script for moving swapfile in Mac OS X 10.4
#
# Copyright (c) 2004-2006 Dave Bayer
# Subject to the terms and conditions of the MIT License.

(my $rc_swapfile = <<'EOF') =~ s/^: ?//mg;
: #!/bin/sh
: #
: # rc.swapfile  --  set up a separate swapfile partition in Mac OS X 10.4
: #
: # Copyright (c) 2004-2006 Dave Bayer
: # Subject to the terms and conditions of the MIT License.
: #
: # http://www.math.columbia.edu/~bayer/OSX/swapfile/
: #
: # Permission is hereby granted, free of charge, to any person obtaining a
: # copy of this software and associated documentation files (the "Software"),
: # to deal in the Software without restriction, including without limitation
: # the rights to use, copy, modify, merge, publish, distribute, sublicense,
: # and/or sell copies of the Software, and to permit persons to whom the
: # Software is furnished to do so, subject to the following conditions:
: # 
: # The above copyright notice and this permission notice shall be included in
: # all copies or substantial portions of the Software.
: # 
: # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
: # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
: # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
: # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
: # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
: # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
: # DEALINGS IN THE SOFTWARE.
:
: swapsearch='0 1 2 3 4 5 6 7 8 9'
: swapmap='10'
: swapvolume='Swap'
: swaptype='ufs'
: swapprint='f7904e44f9d7b5043d90126fb74a0bca'
: swaplog='/var/log/rc.swapfile.log'
:
: echo >>${swaplog}
: echo `date` >>${swaplog}
:
: swskip='d41d8cd98f00b204e9800998ecf8427e'
: swcount=1
: swfound=0
: while [ $swcount -le 5 ] && [ $swfound -eq 0 ]
: do
: 	if [ $swcount -ge 2 ]; then echo '--' >>${swaplog}; fi
: 	for swapdisk in ${swapsearch}
:	do
: 		swaphash=`pdisk /dev/disk${swapdisk} -dump 2>/dev/null | grep -v '/dev/disk' | md5 -q`
: 		if echo ${swaphash} | grep -qF ${swskip}; then continue; fi
: 		echo  /dev/disk${swapdisk} ${swaphash} >>${swaplog}
:
: 		if echo ${swaphash} | grep -qF ${swapprint}
:		then
: 			swfound=1
:			break
:		fi
:	done
: 	sleep 2
: 	swcount=`expr $swcount + 1`
: done
:
: swmounted=0
: if [ $swfound -eq 1 ]
: then
: 	swapdevice=/dev/disk${swapdisk}s${swapmap}
:	swcount=0
:	swmounted=1
: 	until /sbin/mount | grep -qF ${swapdevice}
:	do
:		if [ $swcount -ge 5 ]
:		then
:			echo "Unable to mount swap volume ${swapvolume}; using default configuration" >>${swaplog}
:			swmounted=0
:			break
:		fi
:		sleep $swcount
:		if [ $swcount -eq 2 ]
:		then
: 			echo "/sbin/fsck -y ${swapdevice}" >>${swaplog}
: 			/sbin/fsck -y ${swapdevice} >/dev/null 2>&1
:			sleep 1
:		fi
: 		echo "/sbin/mount -vt ${swaptype} ${swapdevice} /Volumes/${swapvolume}" >>${swaplog}
:		/sbin/mount -vt ${swaptype} ${swapdevice} "/Volumes/${swapvolume}" >>${swaplog} 2>&1
:		sleep $swcount
: 		swcount=`expr $swcount + 1`
:	done
: else
:	echo "Swap volume ${swapvolume} not found; using default configuration" >>${swaplog}
: fi
:
: if [ $swmounted -eq 1 ]
: then
: 	if [ -f "/Volumes/${swapvolume}/.enablevm" ]
:	then
: 		echo "Using ${swapdevice} for swapfile" >>${swaplog}
: 		if [ -f ${swapdir}/swapfile0 ]; then rm -rf ${swapdir}/swap*; fi
: 		swapdir="/Volumes/${swapvolume}/.vm"
: 	else
: 		echo "/Volumes/${swapvolume}/.enablevm not found; using default configuration" >>${swaplog}
: 		echo "/sbin/umount -v /Volumes/${swapvolume}" >>${swaplog}
: 		/sbin/umount -v "/Volumes/${swapvolume}" >>${swaplog} 2>&1
: 	fi
: fi
:
: unset swapsearch swapmap swapvolume swaptype swapprint swskip swaplog swcount swfound swapdisk swaphash swapdevice swmounted
EOF

(my $help = <<'EOF') =~ s/^: ?//mg;
:
: Usage:
:
: 	swapfile.pl install volume
: 	swapfile.pl uninstall
: 	swapfile.pl inspect
: 	swapfile.pl automount bool
: 	swapfile.pl cleanup volume
:	swapfile.pl volumes
:
: Examples:
:
: 	sudo swapfile.pl install Swap
: 	Moves swapfile to partition mounted at /Volumes/Swap, on next restart
:
: 	sudo swapfile.pl uninstall
: 	Restores location of swapfile to system partition, on next restart
:
: 	swapfile.pl inspect
: 	View diagnostic information about current status of swap partition
:
: 	sudo swapfile.pl automount true
: 	Sets system preference to mount external drives during startup
:
: 	[sudo] swapfile.pl cleanup volume
: 	Remove swap files from volume no longer used for swapping
:
: 	[sudo] swapfile.pl volumes
: 	View disk fingerprints and associated volumes
:
EOF

my ($rc_key, $rc_before, $rc_insert, $rc_remove, %rc_md5, $rc_swapfile_md5, $hr, %run, $do, $arg);

$rc_key = ".enablevm";
$rc_before = "swapdir=/private/var/vm";
$rc_insert = "if [ -f /etc/rc.swapfile ]; then . /etc/rc.swapfile; fi # inserted locally";

%rc_md5 = (
	# OS X 10.3 /etc/rc
	'79c0a57e77161ed614dfc72e3bf833f5' => 0,
	'cdb80266e5ee95f478ced5e32142dc46' => 1,
	
	# OS X 10.4 /etc/rc
	'0406f688163230496ee55f85fdd413da' => 0,
	'64e03196440f0cd5c4bbbe563d269d55' => 1,
);

sub cmd {
	my ($do) = @_;
	print "\n    % $do\n";
	my $res = `$do`;
	(my $show = $res) =~ s/^/    /mg;
	print $show;
	$res;
}

sub rc_modded {
	my $fingerprint = `md5 -q /etc/rc`;
	chop($fingerprint);
	my $mod = $rc_md5{$fingerprint};
	if (! defined($mod)) {
		printf "Warning: unrecognized version of /etc/rc\n%s\n", $fingerprint;
		$mod = `grep -F "$rc_insert" "/etc/rc"` ? 1 : 0;
	}
	if ($mod) {
		print "/etc/rc calls /etc/rc.swapfile\n";
	} else {
		print "/etc/rc does not call /etc/rc.swapfile\n";
	}
	$mod;
}

sub edit_rc {
	local $/;

	open(FILE,"</etc/rc") or die "unable to read from file /etc/rc\n\n";
	$_ = <FILE>;
	close(FILE);
	
	if ($do eq "install") {
		s:($rc_before\n):$1\n$rc_insert\n\n:;
	}
	elsif ($do eq "uninstall") {
		(my $rc_delete = $rc_insert) =~ s:\[:\\[:;
		s:\n\s*$rc_delete\s*:\n:;
	}
	
	open(FILE,">/etc/rc") or die "unable to write to file /etc/rc\n\n";
	print FILE;
	close(FILE);
}

sub automount_status {
	my $status = "false";
	if ( -f "/Library/Preferences/SystemConfiguration/autodiskmount.plist") {
		$status = `defaults read /Library/Preferences/SystemConfiguration/autodiskmount AutomountDisksWithoutUserLogin`;
		$status = $status == 1 ? "true" : "false";
		printf "AutomountDisksWithoutUserLogin is %s\n\n", $status;
	}
	else {
		printf "autodiskmount.plist has not yet been created\n\n";
	}
	$status;
}

sub install_cmd {
	my ($vol) = @_;
	local $/;
	
	die "/etc/rc does not support whitespace in swap volume names\n\n" if $vol =~ /\s/;
	(my $df = cmd("df | grep '/Volumes/$vol\$'")) or die "/Volumes/$vol not found\n\n";
	(my $disk = $df) =~ s:/dev/disk(\d*)s\d*.*\n:$1:;
	(my $map = $df) =~ s:/dev/disk\d*s(\d*).*\n:$1:;
	
	my $entry = cmd("pdisk /dev/disk$disk -partitionEntry $map");
	my $type = "hfs";
	if (1 == `echo '$entry' | grep -c ' Apple_HFS '`) { $type = "hfs"; }
	elsif (1 == `echo '$entry' | grep -c ' Apple_UFS '`) { $type = "ufs"; }
	else { print "\nWarning: unable to determine type of partition format; defaulting to hfs\n"; }
	
	my $fingerprint = cmd("pdisk /dev/disk${disk} -dump 2>/dev/null | grep -v '/dev/disk' | md5 -q");
	chop($fingerprint);
	my $skip = `echo -n | md5 -q`;
	chop($skip);

	my $search = '0 1 2 3 4 5 6 7 8 9';
	$search =~ s:$disk ?::;
	$search = "$disk " . $search;
	
	if (-f "/etc/rc.swapfile") {
		print "\n/etc/rc.swapfile already exists, and will be updated\n"
	}
	else {
		print "\ncreating /etc/rc.swapfile\n"
	}

	$_ = $rc_swapfile;
	
	s:(swapsearch=)'[ \d]*':$1'$search':;
	s:(swapmap=)'\d*':$1'$map':;
	s:(swapvolume=)'\w*':$1'$vol':;
	s:(swaptype=)'\w*':$1'$type':;
	s:(swapprint=)'\w*':$1'$fingerprint':;
	s:(swskip=)'\w*':$1'$skip':;

	open(FILE,">/etc/rc.swapfile") or die "unable to write to file /etc/rc.swapfile\n\n";
	print FILE;
	close(FILE);
	
	cmd("grep '^swap.*=\'.*\'\$' /etc/rc.swapfile");
	print "\n";
		
	automount_status();
	if (! rc_modded()) {
		print "editing /etc/rc to insert call to rc.swapfile\n";
		edit_rc();
	}
	print "\n";
	
	if (-f "/Volumes/$vol/$rc_key") {
		print "/Volumes/$vol/$rc_key already exists\n";
	}
	else {
		print "writing /Volumes/$vol/$rc_key\n";
		`echo > '/Volumes/$vol/$rc_key'`;
	}
	print "\n";
}

sub uninstall_cmd {
	print "\n";

	automount_status();
	if (rc_modded()) {
		print "editing /etc/rc to delete call to rc.swapfile\n\n";
		edit_rc();
	}
	if (-f "/etc/rc.swapfile") {
		print "deleting /etc/rc.swapfile\n";
		`rm /etc/rc.swapfile`;
	}
	else {
		print "/etc/rc.swapfile not found\n";
	}
	print "\n";
}

sub inspect_cmd {
	print "\n";
	automount_status();
	rc_modded();
	cmd("grep '^swap.*=\'.*\'\$' /etc/rc.swapfile") if ( -f "/etc/rc.swapfile");
	cmd("tail -n 16 /var/log/rc.swapfile.log");
	my $path = cmd("ps -wwax | grep dynamic_pager | grep -v grep");
	$path =~ s/.* (\S+)\n/$1/;
	cmd("ls -l $path*");
	print "\n";
}

sub automount_cmd {
	my ($bool) = @_;
	$bool eq "true" or $bool eq "false" or die "true or false required as parameter to automount\n\n";
	print "\n";
	if ($bool ne automount_status()) {
		print "setting AutomountDisksWithoutUserLogin to $arg\n";
		`defaults write /Library/Preferences/SystemConfiguration/autodiskmount AutomountDisksWithoutUserLogin -bool $arg`;
	}
}

sub cleanup_cmd {
	my ($vol) = @_;

	print "\n";
	die "/Volumes/$vol not found\n\n" unless `df | grep '/Volumes/$vol\$'`;
	die "$vol is in use as the swap partition\n\n" if `ps -wwax | grep dynamic_pager -m1 | grep  '/Volumes/$vol'`;
	
	automount_status();
	if (-f "/Volumes/$vol/$rc_key") {
		print "deleting /Volumes/$vol/$rc_key\n";
		`rm '/Volumes/$vol/$rc_key'`;
	}
	else {
		print "/Volumes/$vol/$rc_key not found\n";
	}
	if (-d "/Volumes/$vol/.vm") {
		print "deleting /Volumes/$vol/.vm\n";
		`rm -r '/Volumes/$vol/.vm'`;
	}
	else {
		print "/Volumes/$vol/.vm not found\n";
	}
	print "\n";
}

sub volumes_cmd {
	my @mount;
	for my $line (split /\n/, `mount | grep /dev/disk | sort`)
	{
		$line =~ s:^/dev/disk(\d+)s\d+ on (.*) \([^()]*\)$:$1\n$2:;
		my ($disk, $vol) = split /\n/, $line;
		$vol =~ s:/Volumes/::;
		if ($vol =~ /[,\s]/) { $vol =~ s/.*/"$vol"/; }
		push @{$mount[$disk]}, $vol;
	}
	
	my $skip = `echo -n | md5 -q`;
	chop $skip;
	print "\n";
	for (my $disk=0; ; $disk++)
	{
		my $hash = `pdisk /dev/disk${disk} -dump 2>/dev/null | grep -v '/dev/disk' | md5 -q`;
		chop $hash;
		if ( $hash eq $skip )
		{
			if ($disk == 0) { next; }
			else { last; }
		}
		printf "%s /dev/disk%d ", $hash, $disk;
		for my $vol (@{$mount[$disk]}) { printf "%s ", $vol; }
		print "\n";
	}
	print "\n";
}

%run = (
	'install' => [\&install_cmd, 1],
	'uninstall' => [\&uninstall_cmd, 0],
	'inspect' => [\&inspect_cmd, 0],
	'automount' => [\&automount_cmd, 1],
	'cleanup' => [\&cleanup_cmd, 1],
	'volumes' => [\&volumes_cmd, 0],
);

($do, $arg) = @ARGV;
if (not $do or not $run{$do} or $run{$do}[1] != $#ARGV) { 
		print $help;
		exit(1);
}

$run{$do}[0]($arg);
print "done\n\n";