name : linux-check-removal #!/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);