path: root/scripts/vyatta-boot-image.pl

#!/usr/bin/perl

# **** License ****
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
#
# 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.
#
# This code was originally developed by Vyatta, Inc.
# Portions created by Vyatta are Copyright (C) 2007 Vyatta, Inc.
# All Rights Reserved.
#
# Author: An-Cheng Huang, Bob Gilligan
# Date: January, 2010
# Description: Script to manage system images.  Provides the ability to
#	display status of images, select the default image to boot, and
#	to delete images.
#
# **** End License ****

use strict;
use warnings;
use Getopt::Long;
use File::Temp qw/ :mktemp /;

# 
# Constants
# 
my $UNION_BOOT = '/live/image/boot';
my $UNION_GRUB_CFG = "$UNION_BOOT/grub/grub.cfg";
my $VER_FILE = '/opt/vyatta/etc/version';
my $OLD_IMG_VER_STR = 'Old-non-image-installation';
my $OLD_GRUB_CFG = '/boot/grub/grub.cfg';
my $DISK_BOOT = '/boot';

# 
# Globals
# 
my $grub_cfg;	# Pathname of grub config file we will use.

# This function parses the grub config file and returns a hash array
# of the parsed data.  There is one element of the array for each grub
# config file entry.  Each element is a hash that contains:  The "index" of
# entry in the grub config file, the "version" string of the entry, the
# "terminal type" of the entry -- "kvm" or "serisl", and a flag indicating
# whether the entry is a "lost password reset" boot menu item.
#
sub parseGrubCfg {
  my $fd = undef;
  return undef if (!open($fd, '<', $grub_cfg));

  my %ghash = ();
  my @entries = ();
  my $in_entry = 0;
  my $idx = 0;
  while (<$fd>) {
    if ($in_entry) {
      if (/^}/) {
        $in_entry = 0;
        ++$idx;
      } elsif (/^\s+linux /) {
        my %ehash = (
          'idx' => $idx,
          'ver' => undef,
          'term' => undef,
          'reset' => undef
        );
        # kernel line
        if (/^\s+linux \/boot\/([^\/ ]+)\/.* boot=live /) {
          # union install
          $ehash{'ver'} = $1;
        } else {
          # old install
          $ehash{'ver'} = $OLD_IMG_VER_STR;
        }
        if (/console=tty0.*console=ttyS0/) {
          $ehash{'term'} = 'serial';
        } else {
          $ehash{'term'} = 'kvm';
        }
        if (/standalone_root_pw_reset/) {
          $ehash{'reset'} = 1;
        } else {
          $ehash{'reset'} = 0;
        }
        push @entries, \%ehash;
      }
    } elsif (/^set default=(\d+)$/) {
      $ghash{'default'} = $1;
    } elsif (/^menuentry /) {
      $in_entry = 1;
    } 
  }
  close($fd);
  $ghash{'entries'} = \@entries;
  return \%ghash;
}

# This function deletes the entries for the specified version from the grub
# config file. returns undef if successful. Otherwise it returns an 
# error message.
#
sub deleteGrubEntries {
  my ($del_ver) = @_;

  my $rfd = undef;
  return 'Cannot delete GRUB entries' if (!open($rfd, '<', $grub_cfg));
  my ($wfd, $tfile) = mkstemp('/tmp/boot-image.XXXXXX');

  my @entry = ();
  my ($in_entry, $ver) = (0, 0);
  while (<$rfd>) {
    next if (/^$/); # ignore empty lines
    if ($in_entry) {
      if (/^}/) {
        if ($ver ne $del_ver) {
          # output entry
          print $wfd "\n";
          foreach my $l (@entry) {
            print $wfd $l;
          }
          print $wfd "}\n";
        }
        $in_entry = 0;
        $ver = 0;
        @entry = ();
      } else {
	  if (/^\s+linux/) {
	      if (/^\s+linux \/boot\/([^\/ ]+)\/.* boot=live /) {
		  # kernel line
		  $ver = $1;
	      } else {
		  $ver = $OLD_IMG_VER_STR;
	      }
	  }
	  push @entry, $_;
      }
    } elsif (/^menuentry /) {
      $in_entry = 1;
      push @entry, $_;
    } else {
      print $wfd $_;
    } 
  }
  close($wfd);
  close($rfd);

  my $p = (stat($grub_cfg))[2];
  return 'Failed to modify GRUB configuration'
    if (!defined($p) || !chmod(($p & 07777), $tfile));
  system("mv $tfile $grub_cfg");
  return 'Failed to delete GRUB entries' if ($? >> 8);
  return undef;
}

# This function takes the default terminal type and a list of all grub
# config file entries as generated by parseGrubConfig() and returns
# the "boot list".  This list contains one entry for each image
# version.
#
sub getBootList {
  my ($dterm, $entries) = @_;
  my %vhash = ();
  my @list = ();
  foreach (@{$entries}) {
    my ($ver, $term) = ($_->{'ver'}, $_->{'term'});
    next if ($_->{'reset'}); # skip password reset entry
    next if ($term ne $dterm); # not the default terminal
    next if (defined($vhash{$ver})); # version already in list

    $vhash{$ver} = 1;
    push @list, $_;
  }
  return \@list;
}


# Prints the boot list generated by getBootList(). If the argument
# $brief is set, display the entries for machine instead of human
# consumption:  One entry per line showing the the version string only.
#
sub displayBootList {
  my ($didx, $entries, $brief) = @_;
  my $running_ver = curVer();
  for my $i (0 .. $#{$entries}) {
    my $di = $i + 1; 
    my $ver = $ {$entries}[$i]->{'ver'};
    my $m = '';
    if ($didx == $ {$entries}[$i]->{'idx'}) {
      $m = ' (default boot)';
    }
    
    if ($ver eq $running_ver) {
	$m .= ' (running version)';
    }

    if (defined($brief)) {
	print "$ver\n";
    } else {
	printf "  %2d: %s%s\n", $di, $ver, $m;
    }
  }
}

# Sets the grub config file default pointer to the boot list entry
# number passed in.
#
sub doSelect {
  my ($resp, $def_ver, $bentries, $new_ver) = @_;
  my $new_idx;
  if (defined($new_ver)) {
      for my $i (0 .. $#{$bentries}) {
	  if ($ {$bentries}[$i]->{'ver'} eq $new_ver) {
	      $new_idx = $ {$bentries}[$i]->{'idx'};
	      last;
	  }
      }
  } else {
      $new_idx = $ {$bentries}[$resp]->{'idx'};
      $new_ver = $ {$bentries}[$resp]->{'ver'};
  }
  if ($new_ver eq $def_ver) {
      print "The default boot image has not been changed.\n";
      exit 0;
  }

  system("sed -i 's/^set default=.*\$/set default=$new_idx/' $grub_cfg");
  if ($? >> 8) {
    print "Failed to set the default boot image. Exiting...\n";
    exit 1;
  }
  print <<EOF;
Default boot image has been set to "$new_ver".
You need to reboot the system to start the new default image.

EOF
  exit 0;
}

# Set the grub default pointer to the entry whose name is passed in
#
sub select_by_name {
    my ($new_def_ver, $def_term) =  @_;
    my $def_index;

    # Re-scan the the grub config file to get the current indexes
    # of each entry.
    my $gref = parseGrubCfg();
    if (!defined($gref)) {
	print "Cannot parse GRUB configuration file. Exiting...\n";
	exit 1;
    }

    # Find the entry that matches the new default version
    my $entries = $gref->{'entries'};
    my $entry;
    foreach $entry (@{$entries}) {
	# Skip entries that are not using the same term type as before
	next if ($entry->{'term'} ne $def_term);
	# Skip the password reset entries
	next if ($entry->{'reset'});
	if ($entry->{'ver'} eq $new_def_ver) {
	    $def_index = $entry->{'idx'};
	    last;
	}
    }

    if (!defined($def_index)) {
	print "Can't find entry for $new_def_ver in grub config file.\n";
	exit 1;
    }

    # Set default pointer in grub config file to point to the new
    # default version.
    system("sed -i 's/^set default=.*\$/set default=$def_index/' $grub_cfg");
    if ($? >> 8) {
	print "Failed to set the default boot image. Exiting...\n";
	exit 1;
    }
}

# Returns the version string of the currently running system.
#
sub curVer {
    my ($fd, $ver) = (undef, undef);

    my $image_boot = `grep -e '^unionfs / unionfs.*squashfs=ro' /proc/mounts`;
    if ($image_boot ne "") {
	open($fd, '<', $VER_FILE) or return undef;
	while (<$fd>) {
	    next if (!(/^Version\s+:\s+(\S+)$/));
	    $ver = $1;
	    last;
	}
	close($fd);
    } else {
	$ver = $OLD_IMG_VER_STR;
    }
    return $ver;
}

# Deletes all of the files belonging to the disk-based non-image
# installation.
#
sub del_non_image_files {
    my $logfile="/var/log/vyatta/disk-image-del-";
    $logfile .= `date +%F-%T`;
    system("touch $logfile");
    system("echo Deleting disk-based system files at: `date` >> $logfile");
    system("echo Run by: `whoami` >> $logfile");

    my @entries=</live/image/*>;
    my $entry;
    foreach $entry (@entries) {
	if ($entry eq "/live/image/boot") {
	    print "Skipping $entry.\n";
	} else {
	    print "Deleting $entry...";
	    system ("echo deleting $entry >> $logfile");
	    system ("rm -rf $entry >> $logfile 2>&1");
	    print "\n";
	}
    }
    system ("echo done at: `date` >> $logfile");
}

# Deletes all of the grub config file entries associated with that
# image and deletes the files associated with that entry.  If caller
# provides the version string of the image to be deleted ($del_ver),
# that version is targetted.  Otherwise, the caller must provide the
# index into the boot entries list ($resp) to identify the image to be
# deleted.
#
sub doDelete {
  my ($resp, $orig_def_ver, $def_ter, $bentries, $del_ver) = @_;
  if (!defined($del_ver)) {
      $del_ver = $ {$bentries}[$resp]->{'ver'};
  }
  my $boot_dir;

  my $cver = curVer();
  if (!defined($cver)) {
      print "Cannot verify current version. Exiting...\n";
      exit 1;
  }
  if ($cver eq $del_ver) {
      print "Cannot delete current running image. Reboot into a different\n";
      print "image to delete this image.  Exiting...\n";
      exit 1;
  }

  print "Are you sure you want to delete the\n\"$del_ver\" image? ";
  print '(Yes/No) [No]: ';
  $resp = <STDIN>;
  if (!defined($resp)) {
    $resp = 'no';
  }
  chomp($resp);
  $resp = lc($resp);
  if ($resp ne 'yes') {
    print "Image is NOT deleted. Exiting...\n";
    exit 1;
  }

  if (-d $UNION_BOOT) {
    $boot_dir = $UNION_BOOT;
  } elsif (-d $DISK_BOOT) {
    $boot_dir = $DISK_BOOT;
  }

  if (($del_ver ne $OLD_IMG_VER_STR) && (! -d "$boot_dir/$del_ver")) {
    print "Cannot find the target image. Exiting...\n";
    exit 1;
  }

  print "Deleting the \"$del_ver\" image...\n";
  my $err = deleteGrubEntries($del_ver);
  if (defined($err)) {
    print "$err. Exiting...\n";
    exit 1;
  }

  if ($del_ver eq $OLD_IMG_VER_STR) {
      del_non_image_files();
  } else {
    system("rm -rf '$boot_dir/$del_ver'");
    if ($? >> 8) {
      print "Error deleting the image. Exiting...\n";
      exit 1;
    }
  }

  print "Done\n";

  # Need to reset the grub default pointer becuase entry before default
  # may have been deleted, or the default entry itself may have
  # been deleted.
  if ($del_ver eq $orig_def_ver) {
      select_by_name($cver, $def_ter);
      print "The default image has been changed to the currently running image:\n";
      print "$cver\n";
  } else {
      select_by_name($orig_def_ver, $def_ter);
  }

  exit 0;
}

#
# Main section
# 

my ($show, $del, $sel, $list) = (undef, undef, undef, undef);

GetOptions(
  'show' => \$show,
  'delete:s' => \$del,
  'select:s' => \$sel,
  'list' => \$list
);

if (-e $UNION_GRUB_CFG) {
    $grub_cfg = $UNION_GRUB_CFG;
} elsif (-e $OLD_GRUB_CFG) {
    $grub_cfg = $OLD_GRUB_CFG;
} else {
    print "Can not open Grub config file\n";
    exit 1;
}

my $gref = parseGrubCfg();
if (!defined($gref)) {
    print "Cannot find GRUB configuration file. Exiting...\n";
    exit 1;
}

my $def_idx = $gref->{'default'};
my $entries = $gref->{'entries'};
if (!defined($def_idx) || !defined($entries)
    || !defined(${$entries}[$def_idx])) {
  print "Error parsing GRUB configuration file. Exiting...\n";
  exit 1;
}
my $def_ver = ${$entries}[$def_idx]->{'ver'};
my $def_term = ${$entries}[$def_idx]->{'term'};

my $bentries = getBootList($def_term, $entries);
if ($#{$bentries} < 0) {
  print "No images found. Exiting...\n";
  exit 1;
}

if (defined($list)) {
    displayBootList($def_idx, $bentries, 1);
    exit 0;
}

if (defined($sel) && ($sel ne "")) {
    # User has specified entry to select
    doSelect(0, $def_ver, $bentries, $sel);
    print "Done.\n";
    exit 0;
}

if (defined($del) && ($del ne "")) {
    # User has specified entry to delete
    doDelete(0, $def_ver, $def_term, $bentries, $del);
    print "Done.\n";
    exit 0;
}

my $msg = 'The system currently has the following image(s) installed:';
if (defined($del)) {
  # doing delete
  $msg = 'The following image(s) can be deleted:';
}
print "$msg\n\n";
displayBootList($def_idx, $bentries);
print "\n";

exit 0 if (defined($show) || (!defined($sel) && !defined($del))); # show-only

# for doing select
my $prompt_msg = 'Select the default boot image: ';
my $error_msg = 'Invalid selection. Default is not changed.';
if ($del) {
  # doing delete
  $prompt_msg = 'Select the image to delete: ';
  $error_msg = 'Invalid selection. Nothing is deleted.';
}

print "$prompt_msg";
my $resp = <STDIN>;
if (defined($resp)) {
  chomp($resp);
  if (!($resp =~ /^\d+$/) || ($resp < 1) || ($resp > ($#{$bentries} + 1))) {
    $resp = undef;
  }
}
if (!defined($resp)) {
  print "$error_msg Exiting...\n";
  exit 1;
}
print "\n";

$resp -= 1;

if (defined($sel)) {
  doSelect($resp, $def_ver, $bentries);
} elsif (defined($del)) {
  doDelete($resp, $def_ver, $def_term, $bentries);
} else {
    print "Unknown command.\n";
    exit 1;
}

exit 0;