#!/usr/bin/perl
# Copyright 1996-2006 Manoj Srivastava
# Copyright 2016 Ben Hutchings
#
# This program 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.
#
# 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.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
use strict;
use warnings;
use FileHandle;
use POSIX ();
sub usage {
my $fh = shift;
print $fh (<< "EOT");
Usage: $0 VERSION
This command is intended to be called from the prerm maintainer scripts
of Linux kernel packages.
The VERSION argument must be the kernel version string as shown by
'uname -r' and used in filenames.
If the currently running kernel matches VERSION, linux-check-removal
will normally prompt the user to confirm this potentially dangerous
action and will fail if the user chooses to abort. However, if the
current environment is in a chroot or container, or if debconf
prompts are disabled, it will always succeed without prompting.
EOT
}
sub usage_error {
usage(*STDERR{IO});
exit 2;
}
# Check usage early, before Debconf::Client::ConfModule initialises and
# adds its complaints about permissions
BEGIN {
if (@ARGV != 1) {
usage_error();
}
if ($ARGV[0] eq 'help' or grep({$_ eq '--help'} @ARGV)) {
usage(*STDOUT{IO});
exit 0;
}
}
# Are we in a container? Check for $container in pid 1's environment.
sub in_container {
my $res = 0;
if (my $fh = new FileHandle('/proc/1/environ', 'r')) {
local $/ = "\0";
$res = grep(/^container=/, <$fh>);
close($fh);
}
return $res;
}
# Are we in in a chroot? Compare root device and inode numbers with pid 1.
sub in_chroot {
my @my_root_st = stat('/');
my @pid1_root_st = stat('/proc/1/root');
return @my_root_st && @pid1_root_st &&
($my_root_st[0] != $pid1_root_st[0] || $my_root_st[1] != $pid1_root_st[1]);
}
sub check {
my ($version) = @_;
my (undef, undef, $running, undef, undef) = POSIX::uname();
if ($running ne $version || in_chroot() || in_container()) {
exit 0;
}
if (!exists($ENV{'DEBIAN_FRONTEND'}) ||
$ENV{'DEBIAN_FRONTEND'} ne 'noninteractive') {
use Debconf::Client::ConfModule qw(:all);
my $title = 'linux-base/removing-title';
my $question = "linux-base/removing-running-kernel";
my ($ret, $seen, $answer);
# debconf only generates a title automatically when used directly
# from a maintainer script. Also, the automatic title says we are
# 'configuring' a package but we're not.
($ret) = subst($title, 'package', $ENV{DPKG_MAINTSCRIPT_PACKAGE});
if ($ret) {
die "Failed to substitute package name in title: $ret";
}
($ret) = settitle($title);
if ($ret) {
die "Failed to set title: $ret";
}
($ret) = fset($question, 'seen', 'false');
if ($ret) {
die "Failed to reset seen flag for $question: $ret";
}
($ret) = reset($question);
if ($ret) {
die "Failed to reset answer for $question: $ret";
}
($ret) = subst($question, 'running', $running);
if ($ret) {
die "Failed to substitute version in $question: $ret";
}
($ret, $seen) = input('critical', $question);
if ($ret && $ret != 30) {
die "Failed to prepare question $question: $ret $seen";
}
($ret, $seen) = go();
if ($ret && $ret != 30) {
die "Failed to ask question $question: $ret $seen";
}
($ret, $answer) = get($question);
if ($ret) {
die "Failed to retrieve answer for $question: $ret $answer";
}
if ($answer eq 'true') {
print STDERR "E: Aborting removal of the running kernel\n";
exit 1;
}
}
print STDERR "W: Removing the running kernel\n";
exit 0;
}
check(@ARGV);
Mini Shell