Run user programs as nobody:nogroup

[gruntmaster-daemon.git] / gruntmaster-exec

diff --git a/gruntmaster-exec b/gruntmaster-exec
index 36b71d43319a52b512fcb4bdd74205adf1014ff9..e7d7363d4c44308c0622a32e4ecbb7565682c88c 100755 (executable)
--- a/gruntmaster-exec
+++ b/gruntmaster-exec
@@ -1,14 +1,113 @@
-#!/usr/bin/perl -w
+#!/usr/bin/perl
 use v5.14;
 use strict;
+use warnings;
+
+use constant +{
+       # Accepted
+       AC => 0,
+
+       # Internal server error
+       ERR => -1,
+
+       # All other errors
+       WA => 1,
+       NZX => 2,
+       TLE => 3,
+       OLE => 4,
+       DIED => 5,
+       REJ => 10,
+};
+# These constants are changed by ex/makevm
+use constant USER => 65534;
+use constant GROUP => 65534;
 
 use BSD::Resource qw/setrlimit RLIMIT_AS RLIMIT_FSIZE/;
+use IPC::Signal qw/sig_name sig_num/;
 use sigtrap qw/XFSZ/;
 
-##################################################
+use Getopt::Long;
+use POSIX qw//;
+use Time::HiRes qw/alarm/;
+
+my (@fds, $timeout, $mlimit, $olimit, $nobody);
+my $close = 1;
+
+GetOptions(
+       "fd=s"      => \@fds,
+       "timeout=f" => \$timeout,
+       "mlimit=i"  => \$mlimit,
+       "olimit=i"  => \$olimit,
+       "close!"    => \$close,
+       "nobody!"   => \$nobody,
+);
+
+my $ret = fork // die 'Cannot fork';
+if ($ret) {
+       my $tle;
+       local $SIG{ALRM} = sub { kill KILL => $ret; $tle = 1};
+       alarm ($timeout || 5);
+       waitpid $ret, 0;
+       alarm 0;
+       my $sig = $? & 127;
+       my $signame = sig_name $sig;
+       exit !say TLE,  "\nTime Limit Exceeded"   if $tle;
+       exit !say OLE,  "\nOutput Limit Exceeded" if $sig && $signame eq 'XFSZ';
+       exit !say DIED, "\nCrash (SIG$signame)"   if $sig && $signame ne 'PIPE';
+       exit !say NZX,  "\nNon-zero exit status: " . ($? >> 8) if $? >> 8;
+       exit !say AC,   "\nAll OK";
+} else {
+       $^F = 50;
+       if ($close) {
+               POSIX::close $_ for 0 .. $^F;
+       }
+       for my $fdstring (@fds) {
+               my ($fd, $file) = split ' ', $fdstring, 2;
+               open my $fh, $file or die $!;
+               my $oldfd = fileno $fh;
+               if ($oldfd != $fd) {
+                       POSIX::dup2 $oldfd, $fd or die $!;
+                       POSIX::close $oldfd or die $!;
+               }
+       }
+       %ENV = (ONLINE_JUDGE => 1, PATH => $ENV{PATH}, HOME => $ENV{HOME});
+       setrlimit RLIMIT_AS, $mlimit, $mlimit or die $! if $mlimit;
+       setrlimit RLIMIT_FSIZE, $olimit, $olimit or die $! if $olimit;
+       POSIX::setgid $nobody ? 65534 : USER;
+       POSIX::setuid $nobody ? 65534 : GROUP;
+       exec @ARGV;
+}
+
+1;
+__END__
+
+=encoding utf-8
+
+=head1 NAME
+
+gruntmaster-exec - Gruntmaster 6000 executor
+
+=head1 SYNOPSIS
+
+  gruntmaster-exec 20000000 111 echo 'Hello, world!'
+
+=head1 DESCRIPTION
+
+gruntmaster-exec is the script used by gruntmasterd to run programs.
+
+The first argument is the address space limit (in bytes), the second argument is the output limit (also in bytes). The rest of the arguments are the command that should be run and its arguments.
+
+gruntmaster-exec sets the resource limits, cleans the environment (except for PATH and HOME), adds the ONLINE_JUDGE environment variable with value 1, and finally C<exec>s the given command.
+
+=head1 AUTHOR
+
+Marius Gavrilescu E<lt>marius@ieval.roE<gt>
+
+=head1 COPYRIGHT AND LICENSE
 
-my ($mlimit, $olimit, @args) = @ARGV;
+Copyright (C) 2014 by Marius Gavrilescu
 
-setrlimit RLIMIT_AS, $mlimit, $mlimit or die $! if $mlimit;
-setrlimit RLIMIT_FSIZE, $olimit, $olimit or die $! if $olimit;
-exec @args;
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.