add flock on temporary directory in /tmp

Since systemd 256~rc3-3, /tmp is regularly cleaned up, removing files
older than 10 days. Since a rootfs contains files with timestamps
potentially much older than that, we exclude our temporary directory by
adding an exclusive lock on it which will stop systemd-tmpfiles from
cleaning up anything in it.

Thanks: Peter Pentchev <roam@ringlet.net>
This commit is contained in:
Johannes Schauer Marin Rodrigues 2024-06-02 08:46:59 +02:00
parent 5f491f2955
commit f3ea5f2676
Signed by untrusted user: josch
GPG key ID: F2CBA5C78FBD83E1

View file

@ -36,7 +36,8 @@ use File::Find;
use Cwd qw(abs_path getcwd);
require "syscall.ph"; ## no critic (Modules::RequireBarewordIncludes)
require "sys/ioctl.ph"; ## no critic (Modules::RequireBarewordIncludes)
use Fcntl qw(S_IFCHR S_IFBLK FD_CLOEXEC F_GETFD F_SETFD);
use Fcntl
qw(S_IFCHR S_IFBLK FD_CLOEXEC F_GETFD F_SETFD LOCK_EX O_RDONLY O_DIRECTORY);
use List::Util qw(any none);
use POSIX
qw(SIGINT SIGHUP SIGPIPE SIGTERM SIG_BLOCK SIG_UNBLOCK strftime isatty);
@ -5759,6 +5760,7 @@ sub main() {
$blocksize = 1048576;
}
my $rootdir_handle;
if (any { $_ eq $options->{format} }
('tar', 'squashfs', 'ext2', 'ext4', 'null')) {
if ($options->{format} ne 'null') {
@ -5789,6 +5791,13 @@ sub main() {
# directory
$options->{root} = tempdir('mmdebstrap.XXXXXXXXXX', TMPDIR => 1);
info "using $options->{root} as tempdir";
# add an flock on the temporary directory to prevent cleanup by systemd
# see section Age in tmpfiles.d(5)
sysopen($rootdir_handle, $options->{root}, O_RDONLY | O_DIRECTORY)
or error "Failed to sysopen $options->{root}: $!\n";
flock($rootdir_handle, LOCK_EX)
or error "Unable to flock $options->{root}: $!\n";
# in unshare and root mode, other users than the current user need to
# access the rootfs, most prominently, the _apt user. Thus, make the
# temporary directory world readable.