tags -1 patch
On Mon, 2022-06-27 at 22:02 +0200, Marc Haber wrote:
>
> /run/adduser please, and probably a simple flock()? lock files in a
> shell script are a minefield for code running as root, I hope it is
> easier in perl.
Good call. I've attached a minimal POC, which works in manual testing,
but automated testing is tricky and there may be edge cases. (This
test is blocking; NB (erroring out) might be easier to test, but which
is the better UX?)
mb
diff --git a/AdduserCommon.pm b/AdduserCommon.pm
index ffb8bac..2330d3a 100644
--- a/AdduserCommon.pm
+++ b/AdduserCommon.pm
@@ -12,11 +12,14 @@
use File::Basename;
+use Fcntl qw(:flock SEEK_END);
use constant PROGNAME => basename($0);
use vars qw(@EXPORT $VAR1);
+my $lockfile;
+
@EXPORT = (
'dief',
'get_group_members',
@@ -280,6 +283,17 @@ sub preseed_config {
}
}
+BEGIN {
+ open($lockfile, '>>', '/run/adduser') or dief "could not open lock file %s!\n", '/run/adduser';
+ flock($lockfile, LOCK_EX) or dief "could not lock file %s!\n", '/run/adduser';
+ seek($lockfile, 0, SEEK_END) or dief "could not seek - %s!\n", '/run/adduser';
+}
+
+END {
+ flock($lockfile, LOCK_UN) or dief "could not unlock file %s - %s!\n", '/run/adduser', "$!";
+ close($lockfile) or dief "could not close lock file %s - %s!\n", '/run/adduser', "$!";
+}
+
# Local Variables:
# mode:cperl
# End:
