Mounting Debian ISO files as Offline Software Repository

If you are not connected to internet, then still you can install packages from Debian Installer ISOs. For example, if Debian 7.0 (Wheezy) ISOs are in directory /media/FreeAgent GoFlex Drive/Softwares/Debian_7.0_Wheezy directory and we want to mount these iso in /mnt/Debian/ directory. The following command can be used:

$ sudo $(which mount_debian.pl) -d /mnt/Debian -g -r "/media/FreeAgent GoFlex Drive/Softwares/Debian_7.0_Wheezy"
Using iso(s) dir '/media/FreeAgent GoFlex Drive/Softwares/Debian_7.0_Wheezy'
Using mount point dir '/mnt/Debian'
...
Total 11 iso(s) mounted successfully.

Unmounting of the iso(s) can be achieved by the following command:

$ sudo $(which mount_debian.pl) -d /mnt/Debian -u -g -r
Running: umount "/mnt/Debian"/*.iso
Running: rmdir "/mnt/Debian"/*.iso
Running: cp "/etc/apt/sources.list.net" "/etc/apt/sources.list"
Running: apt-get update
...

Usage of the command:

$ sudo $(which mount_debian.pl)
/home/mitesh/Perl/mount_debian.pl: Please provide Dir where Debian installer iso(s) are present.
USAGE: /home/mitesh/Perl/mount_debian.pl [options] iso_dir
          -a apt_sources_dir        default  /etc/apt
          -d mount_base_dir         default  /mnt/Debian
          -g                        debug on 
          -r                        apt-get update 
          -u                        unmount 
          iso_dir                   Dir where Debian installer iso(s) are present.

PS: iso_dir is not required with -u command

The mount_debian.sh perl script is given as follows:

#!/usr/bin/perl -w
#===============================================================================
#
#         FILE:  mount_debian.pl
#
#        USAGE:  ./mount_debian.pl 
#
#  DESCRIPTION:  
#
#      OPTIONS:  ---
# REQUIREMENTS:  ---
#         BUGS:  ---
#        NOTES:  ---
#       AUTHOR:  Mitesh Singh Jat (mitesh)
#      COMPANY:  
#      VERSION:  1.0
#      CREATED:  11/07/2013 10:30:04 PM IST
#     REVISION:  ---
#===============================================================================

use strict;
use warnings;

use Getopt::Std;
my $apt_sources_dir = "/etc/apt";
my $mount_point_base = "/mnt/Debian";
my $umount = 0;
my $reload = 0;
my $debug = 0;

sub usage()
{
    print STDERR "USAGE: $0 [options] <iso_dir>\n";
    print STDERR "          -a <apt_sources_dir>    apt sources dir: default  $apt_sources_dir\n";
    print STDERR "          -d <mount_base_dir>     mount point dir: default  $mount_point_base\n";
    print STDERR "          -g                      debug on \n";
    print STDERR "          -r                      apt-get update \n";
    print STDERR "          -u                      unmount \n";
    print STDERR "          <iso_dir>               Dir where Debian installer iso(s) are present.\n";
}

sub run_cmd()
{
    my $cmd = $_[0];
    print "Running: $cmd\n" if $debug;
    system("$cmd");
    my $retval = $?; 
    if ($retval != 0)
    {   
        print STDERR "Error in running: $cmd\nExit code = $retval\n";
    }   
    return ($retval);
}

sub run_cmd_get()
{
    my $cmd = $_[0];
    print "Running: $cmd\n" if $debug;
    my @outs = `$cmd`;
    my $retval = $?;
    if ($retval < 0)
    {
        print STDERR "Error in running: $cmd\nExit code = $retval\n";
        exit($retval);
    }
    chomp(@outs);
    return (@outs);
}
sub take_backup() 
{
    my $file1 = $_[0];
    my $file2 = $_[1];
    my $cmd = "cp \"$file1\" \"$file2\"";
    my $retval = &run_cmd("$cmd");
    if ($retval != 0)
    {
        print STDERR "$0: Cannot copy \"$file1\" to \"$file2\"\n";
        exit(-1);
    }
    return 1;
}
sub reload_repo()
{
    my $file1 = $_[0];
    my $file2 = $_[1];

    my $cmd = "cp \"$file1\" \"$file2\"";
    my $retval = &run_cmd($cmd);
    exit(-1) if ($retval != 0);

    $cmd = "apt-get update";
    $retval = &run_cmd($cmd);
    exit(-1) if ($retval != 0);
}

my %opts;
getopt('a:d:', \%opts);

foreach my $opt (sort keys %opts)
{
    if (!defined($opts{$opt}))
    {
        print STDERR "$0: Requires value for option '$opt'\n";
        &usage();
        exit(-1);
    }
    else 
    {
        if ($opts{$opt} =~ m/^-/) 
        {
            print STDERR "$0: Requires value for option '$opt'\n";
            &usage();
            exit(-1);
        }
    }
}
$apt_sources_dir = $opts{"a"} if (defined($opts{"a"}));
$mount_point_base = $opts{"d"} if (defined($opts{"d"}));
$debug = 1 if (defined($opts{"g"}));
$reload = 1 if (defined($opts{"r"}));
$umount = 1 if (defined($opts{"u"}));

my $apt_dvd = "$apt_sources_dir/sources.list.dvd";
my $apt_net = "$apt_sources_dir/sources.list.net";
my $apt_orig = "$apt_sources_dir/sources.list";

my $retval = 0;
my $cmd;
$retval = `whoami`;
chomp($retval);
unless ($retval eq "root")
{
    print STDERR "$0: Please run this script as 'root' user.\n";
    &usage();
    exit(-1);
}

unless ($umount)
{

if (@ARGV != 1) 
{
    print STDERR "$0: Please provide Dir where Debian installer iso(s) are present.\n";
    &usage();
    exit(-1);
}
my $iso_dir = "$ARGV[0]";
## Check for iso dir presence
unless (-d "$iso_dir") 
{
    print STDERR "$0: Please make sure the iso(s) dir '$iso_dir' is present\n";
    exit(-1);
}
print "Using iso(s) dir '$iso_dir'\n" if ($debug);

## Check for destination dir
unless (-d "$mount_point_base") 
{
    $cmd = "mkdir -p \"$mount_point_base\"";
    $retval = &run_cmd("$cmd");
    if ($retval != 0) 
    {
        print STDERR "$0: Cannot create dir '$mount_point_base'\n";
        exit(-1);
    }
}
print "Using mount point dir '$mount_point_base'\n" if ($debug);

## Taking backup of ftp/http line sources.list
my $is_backed_up = 0;
if (-f "$apt_net") 
{
    ## Take backup only when ftp / http (internet)
    $cmd = "grep -v -e \"^#\" -e \"^\$\" \"$apt_orig\" | egrep -c \"(ftp|http)://\"";
    my @nets = &run_cmd_get($cmd);
    if ($nets[0] > 0) 
    {
        $is_backed_up = &take_backup("$apt_orig", "$apt_net");
    }
}
else
{
    $is_backed_up = &take_backup("$apt_orig", "$apt_net");
}

## Get loop devices
$cmd = "ls /dev/loop[0-9]*";
my @temps = &run_cmd_get($cmd);
my %loop_devices;
my $nloop_devices = @temps;
foreach my $temp (@temps) 
{
    $loop_devices{$temp} = 1;
}
$cmd = "ls \"$iso_dir\" | grep -i \"\.iso\$\"";
@temps = &run_cmd_get($cmd);
my %iso_images;
my $niso_images = @temps;
foreach my $temp (@temps) 
{
    $iso_images{$temp} = 1;
}
$cmd = "df | awk '{print \$1}' | grep \"/dev/loop\"";
@temps = &run_cmd_get($cmd);
my %mounted_loop_devices;
my $nmounted_loop_devices = @temps;
foreach my $temp (@temps) 
{
    $mounted_loop_devices{$temp} = 1;
}

## Check for free loop devices
my $nfree_loops = $nloop_devices - $nmounted_loop_devices;
if ($niso_images > $nfree_loops)
{
    print "Less available loop devices $nfree_loops than isos $niso_images\n" if ($debug);
    my $req_loops = $niso_images - $nfree_loops; 
    if ($nmounted_loop_devices == 0) 
    {
        print "Reloading loop kernel module with extra $req_loops loop devices\n" if $debug;
        $cmd = "rmmod loop";
        $retval = &run_cmd($cmd);
        print "$retval\n";
        exit(-1) if ($retval != 0);
        $cmd = "modprobe loop max_loop=$niso_images";
        $retval = &run_cmd($cmd);
        exit(-1) if ($retval != 0);
    }
    else 
    {
        print STDERR "Please reload 'loop' kernel module. After unloading following loop devices...\n";
        foreach my $temp (sort keys %mounted_loop_devices)
        {
            print STDERR "$temp\n";
        }
        print STDERR "\nrmmod loop\n";
        my $temp = $nmounted_loop_devices + $req_loops;
        print STDERR "\nmodprobe loop max_loop=$temp\n\n";
        exit(-2);
    }
}

## Create entries in sources.list file
open(SFH, ">$apt_orig") or die("$0: Cannot write in file '$apt_orig'\n");
foreach my $iso (sort keys %iso_images)
{
    print "Mounting iso $iso ...\n" if $debug;
    my $dest_dir = "$mount_point_base/$iso";
    unless (-d "$dest_dir") 
    {
        $cmd = "mkdir -p \"$dest_dir\"";
        $retval = &run_cmd($cmd);
        exit(-1) if ($retval != 0);
    }
    $cmd = "df \"$dest_dir\" | grep -c \"^/dev/loop.*\.iso\$\"";
    my @mounts = &run_cmd_get($cmd); 
    if ($mounts[0] == 0) ## Mount only if not mounted
    {
        $cmd = "mount -o loop,ro \"$iso_dir/$iso\" \"$dest_dir\"";
        $retval = &run_cmd($cmd);
        exit(-1) if ($retval != 0);

        ## read distro version dir in dists/
        $cmd = "ls -l \"$dest_dir/dists\" | grep \"^d\" | awk '{print \$(NF)}' | head -1";
        my $version = `$cmd`;
        if (defined($version) and ($version ne ""))
        {
            $cmd = "ls -l \"$dest_dir/dists\"/*/ | grep \"^d\" | sort -u | awk '{print \$(NF)}' | awk '{sec=sec\" \"\$1} END{print sec}'";
            my $sections = `$cmd`;
            if (defined($sections))
            {
                chomp($sections);
                chomp($version);
                print SFH "deb file://$dest_dir $version $sections\n";
            }
        }
    }
}
print SFH "\n## Automatically generated by $0 ##\n";
close(SFH);
print "Total $niso_images iso(s) mounted successfully.\n" if $debug;

## Reload repository if sources.list is updated
if ($is_backed_up and $reload)
{
    &reload_repo("$apt_orig", "$apt_dvd");
}
exit(0);
}
#######################################
## umount code                       ##
#######################################

$cmd = "umount \"$mount_point_base\"/*.iso";
$retval = &run_cmd($cmd);
exit(-1) if ($retval != 0);
$cmd = "rmdir \"$mount_point_base\"/*.iso";
$retval = &run_cmd($cmd);
exit(-1) if ($retval != 0);
if ($reload)
{
    &reload_repo("$apt_net", "$apt_orig");
}
exit(0);

PS: The above script can be used with any Debian Package Management related distros like Ubuntu, Linux Mint, etc.