commit cfb4018d34400e43837e77754519b3c2761b7ae6 Author: Nicolas Vigier boklm@torproject.org Date: Tue Jun 16 19:57:19 2020 +0200

Bug 40001: Add a container script

This script can be used to start/stop containers during rbm builds. --- container | 296 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 296 insertions(+)

diff --git a/container b/container new file mode 100755 index 0000000..3f07f24 --- /dev/null +++ b/container @@ -0,0 +1,296 @@ +#!/usr/bin/perl + +use strict; +use warnings; + +use File::Basename; +use lib dirname($0) . '/lib'; +use RBM qw(exit_error); +use English; +use Getopt::Long; +use Path::Tiny; +use File::Path qw(make_path); +use File::Copy::Recursive qw(pathrmdir rcopy fcopy); +require "syscall.ph"; + +*CLONE_NEWNS = \0x20000; +*CLONE_NEWUTS = \0x4000000; +*CLONE_NEWIPC = \0x8000000; +*CLONE_NEWUSER = \0x10000000; +*CLONE_NEWPID = \0x20000000; +*CLONE_NEWNET = \0x40000000; +our ( + $CLONE_NEWNS, $CLONE_NEWUTS, $CLONE_NEWIPC, + $CLONE_NEWUSER, $CLONE_NEWPID, $CLONE_NEWNET +); + +my @bind_mounts = qw(/dev/console /dev/full /dev/null /dev/ptmx /dev/random + /dev/tty /dev/urandom /dev/zero); + +sub create_devfiles { + my ($rootfsdir) = @_; + my @dirs = qw(pts shm); + my %links = ( + fd => '/proc/self/fd', + stderr => '/proc/self/fd/2', + stdin => '/proc/self/fd/0', + stdout => '/proc/self/fd/1', + ); + make_path("$rootfsdir/dev"); + foreach my $dir (@dirs) { + make_path("$rootfsdir/dev/$dir"); + chmod 0755, "$rootfsdir/dev/$dir"; + } + foreach my $l (keys %links) { + next if -e "$rootfsdir/dev/$l"; + symlink $links{$l}, "$rootfsdir/dev/$l" + or exit_error "Error creating symlink $l"; + } +} + +sub do_mounts { + my ($rootfsdir) = @_; + foreach my $mount (@bind_mounts) { + open my $fh, '>', "$rootfsdir$mount" + or exit_error "error opening $rootfsdir$mount: $!"; + close $fh; + system('mount', '-o', 'bind', $mount, "$rootfsdir$mount") == 0 + or exit_error "Error bind mounting $mount"; + } + system('mount', '-o', 'rbind', '/sys', "$rootfsdir/sys") == 0 + or exit_error 'Error rbind mounting /sys'; + system('mount', '-t', 'proc', 'proc', "$rootfsdir/proc") == 0 + or exit_error 'Error mounting /proc'; + chmod oct(1777), "$rootfsdir/dev/shm"; + system('mount', '-t', 'tmpfs', 'none', "$rootfsdir/dev/shm") == 0 + or exit_error "Error mounting /dev/shm"; +} + +sub do_unmounts { + my ($rootfsdir) = @_; + my @othermounts = qw(/proc /dev/shm); + foreach my $mount (@bind_mounts, @othermounts) { + system('umount', '--no-mtab', "$rootfsdir$mount") == 0 + or warn "Error unmounting $mount"; + } + system('umount', '--no-mtab', '--lazy', "$rootfsdir/sys") == 0 + or warn "Error unmounting /sys"; +} + +sub extract_tar { + my ($rootfsdir, $tarfile) = @_; + make_path($rootfsdir); + system('tar', '--exclude=./dev', '-C', $rootfsdir, '-xf', $tarfile); +}; + +sub create_tar { + my ($rootfsdir, $tarfile) = @_; + system('tar', '--exclude=./dev', '-C', $rootfsdir, '-caf', $tarfile, '.'); +} + +sub run_chroot { + my ($rootfsdir, $cmd) = @_; + create_devfiles($rootfsdir); + do_mounts($rootfsdir); + fcopy('/etc/resolv.conf', "$rootfsdir/etc/resolv.conf"); + local %ENV = (); + system('hostname', 'rbm'); + my $res = system('/usr/sbin/chroot', $rootfsdir, @$cmd); + do_unmounts($rootfsdir); + return $res; +} + +sub copy_file_to { + my ($rootfsdir, $src, $dst, $owner) = @_; + make_path("$rootfsdir/$dst"); + my $filename = fileparse($src); + rcopy($src, "$rootfsdir/$dst/$filename") + or exit_error "Failed to copy $src to $rootfsdir/$dst/$filename"; + return run_chroot($rootfsdir, ['chown', '-R', $owner, $dst]); +} + +sub copy_file_from { + my ($rootfsdir, $src, $dst) = @_; + make_path($dst); + rcopy("$rootfsdir/$src", $dst) + or exit_error "Failed to copy $rootfsdir/$src to $dst"; +} + +sub get_guidmapcmd { + my ($guid) = (@_); + my $config_file = "/etc/sub${guid}"; + my ($id) = ${guid} eq 'uid' ? ($UID) : split(' ', $GID); + my ($current_usergroup) = ${guid} eq 'uid' ? getpwuid($id) : getgrgid($id); + for my $line (path($config_file)->lines) { + chomp $line; + my ($usergroup, $lowerid, $count) = split(':', $line); + next unless ($usergroup eq $current_usergroup || $usergroup eq $id); + return "0 $id 1 1 $lowerid $count"; + } + exit_error "Could not find $guid in $config_file"; +} + +sub unshare_run { + my ($s, $options) = @_; + my $f1 = fork(); + if ($f1 == 0) { + my $ppid = $$; + pipe my $rfh, my $wfh; + my $pid = fork() // exit_error("fork() failed: $!"); + if ($pid == 0) { + close $wfh; + exit_error("read() did not receive EOF") + unless sysread($rfh, my $c, 1) == 0; + my $uidmapcmd = get_guidmapcmd('uid'); + exit_error("newuidmap $ppid $uidmapcmd failed: $!") + unless system("newuidmap $ppid $uidmapcmd") == 0; + my $gidmapcmd = get_guidmapcmd('gid'); + exit_error("newgidmap $ppid $gidmapcmd failed: $!") + unless system("newgidmap $ppid $gidmapcmd") == 0; + exit 0; + } + + my $unshare_flags = $CLONE_NEWUSER | $CLONE_NEWNS | $CLONE_NEWPID | $CLONE_NEWUTS + | $CLONE_NEWIPC; + $unshare_flags |= $CLONE_NEWNET if $options->{'disable-network'}; + syscall &SYS_unshare, $unshare_flags; + close $wfh; + waitpid($pid, 0) or exit_error("waitpid() failed: $!"); + exit_error("failed to set uidmap") if $? >> 8; + syscall(&SYS_setgid, 0) == 0 or exit_error("setgid failed: $!"); + syscall(&SYS_setuid, 0) == 0 or exit_error("setuid failed: $!"); + syscall(&SYS_setgroups, 0, 0) == 0 or exit_error("setgroups failed: $!"); + + my $f2 = fork() // exit_error("fork() failed: $!"); + if ($f2) { + waitpid($f2, 0) or exit_error("waitpid() failed: $!"); + exit $? >> 8; + } + my $res = $s->(); + exit($res ? $res >> 8 : 0); + } + waitpid($f1, 0) or exit_error("waitpid() failed: $!"); + exit $? >> 8; +} + +my %actions = ( + archive => { + descr => 'Archive a container directory', + usage => "$0 archive <container-dir> <dest-tarball>", + run => sub { + usageexit($ARGV[0]) unless @ARGV == 3; + unshare_run( + sub { + return create_tar($ARGV[1], $ARGV[2]); + } + ); + }, + }, + extract => { + descr => 'Extract a container', + usage => "$0 extract <container-dir> <tarball>", + run => sub { + usageexit($ARGV[0]) unless @ARGV == 3; + exit_error "$ARGV[0] already exists" if -e $ARGV[1]; + unshare_run( + sub { + return extract_tar($ARGV[1], $ARGV[2]); + } + ); + }, + }, + remove => { + descr => "Remove a container directory", + usage => "$0 remove <container-dir>", + run => sub { + usageexit($ARGV[0]) unless @ARGV == 2; + exit_error "$ARGV[1] is not a directory" unless -d $ARGV[1]; + unshare_run( + sub { + return pathrmdir($ARGV[1]); + } + ); + }, + }, + put => { + descr => "Copy a file or directory to the container directory", + usage => "$0 put <container-dir> <src> <dst> <owner>", + run => sub { + usageexit($ARGV[0]) unless @ARGV == 5; + exit_error "$ARGV[1] is not a directory" unless -d $ARGV[1]; + my (undef, @args) = @ARGV; + unshare_run( + sub { + return copy_file_to(@args); + } + ); + }, + }, + get => { + descr => "Copy a file or a directory from the container directory", + usage => "$0 get <container-dir> <src> <dst>", + run => sub { + usageexit($ARGV[0]) unless @ARGV == 4; + exit_error "$ARGV[1] is not a directory" unless -d $ARGV[1]; + my (undef, @args) = @ARGV; + unshare_run( + sub { + return copy_file_from(@args); + } + ); + }, + }, + run => { + descr => "Run a command in a container", + usage => "$0 run [--disable-network] [--chroot=<container-dir>] [--] <command> [<arg>...]", + run => sub { + usageexit($_[0]) unless @_>= 2; + shift; + my @options = qw(disable-network! chroot=s); + my %val; + Getopt::Long::GetOptionsFromArray(@_, %val, @options) || exit 1; + my (@cmd) = @_; + unshare_run( + sub { + return $val{chroot} ? run_chroot($val{chroot}, [@cmd]) : system(@cmd); + }, + %val + ); + }, + }, + usage => { + run => &usage, + descr => 'Show usage information for an action', + }, + '--help' => { + run => &usage, + }, +); + +sub usage { + if ($_[1] && $actions{$_[1]} && $actions{$_[1]}->{usage}) { + print $actions{$_[1]}{usage}, "\n"; + } else { + print STDERR "$0 <action> [options]\n"; + print STDERR "$0 usage [action]\n\n"; + print STDERR "Available actions:\n"; + my @actions = grep { $actions{$_}->{descr} } keys %actions; + print STDERR map { " - $_: $actions{$_}->{descr}\n" } @actions; + print STDERR "\nSee '$0 usage <action>' for usage information\n"; + } + exit 0; +} +sub usageexit { + my $cmd = shift; + print STDERR "Incorrect argument(s).\n"; + print STDERR "See '$0 usage $cmd' for usage information\n"; + exit 1; +} + + +if (@ARGV == 0 || !$actions{$ARGV[0]}) { + usage(); + exit 1; +} +usage('usage', $ARGV[0]) if grep { $_ eq '--help' } @ARGV[1..(@ARGV - 1)]; +$actions{$ARGV[0]}->{run}->(@ARGV);