readonly.monitor

#! /usr/bin/perl
use strict;

#
# By Avi, aged 25 1/2 
#

# Parses fstab, and for each device that looks like it should be writeable, 
# attempts to write a file in the root of its mountpoint. Ignores CDs, 
# floppy disks and swap. Anything else can be ignored with a comment in fstab so:
#
#readonly.ignore:/dev/sda1 /dev/sda2
#
# which specifies devices to not check. 
#
# The 'current' version of this can be found at:
#   http://github.com/BigRedS/play/blob/master/readonly.monitor
# click 'raw' for something wgettable. 
#

my $fstab = "/etc/fstab";
my $testFile = ".write-test";

# %fstab is a hash of arrays [mountpoint, filesystem, options] using the /dev
# path as a key
my %fstab;
my @ignore;
open(my $f, "<", $fstab);
while(<$f>){
	if ( /^#readonly\.ignore:/i ){
		@ignore = split(/,\s?/, (split(/:/, $_))[1]);
	}
        # (( begins with a slash or 'UUID'))
        if (( /^\s?\//) || (/^\s?UUID/ )) {
                my ($dev,$mountpoint,$fs,$opt)=(split(/\s+/, $_))[0,1,2,3];
                $fstab{$dev} = [$mountpoint, $fs, $opt];
        }
}

my (@failure);
foreach my $dev (keys(%fstab)){
	if ( !grep(/$dev/, @ignore)) {
	        my $mountpoint = $fstab{$dev}[0];
	        my $fs = $fstab{$dev}[1];
	        my @opt = split(/,/ , $fstab{$dev}[2]);
	        my $file = $mountpoint."/".$testFile;
	        $file =~ s/\/\//\//;
	        #       neither swap nor cd     #mounted auto           # not a floppy disk or a cd
	        if (($fs !~ /(swap|udf)/) && (grep(!/^noauto$/, @opt)) && ($dev !~ /\/dev\/(fd|cdrom)\d/)){
	                `sudo /usr/bin/touch $file 2>&1 > /dev/null`;
	                if ($? != 0){
	                        push(@failure, $dev);
	                }
	        }
	}
}


if ($failure[0]){
        foreach(@failure){
                chomp $_;
                print $_." ";
        }
        if ($failure[1]){
                print "are read-only\n";
        }else{
                print "is read-only\n";
        }
        exit 1;
}else{
        print "All writeable\n";
        exit 0
}