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Oct 29, 2025
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judgedaemon: Replace system and other command executions. #3156

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152 changes: 88 additions & 64 deletions judge/judgedaemon.main.php
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Original file line number Diff line number Diff line change
Expand Up @@ -293,6 +293,41 @@
return trim(ob_get_clean());
}

define('DONT_CARE', new class {});
/**
* Execute a shell command given an array of strings forming the command.
* The command and all its arguments are automatically escaped.
*
* @param array $command_parts The command and its arguments (e.g., ['ls', '-l', '/tmp/']).
* @param mixed $retval The (integer) variable to store the command's exit code.
* @param bool $log_nonzero_exitcode Whether non-zero exit codes should be logged.
*
* @return bool Returns true on success (exit code 0), false otherwise.
*/
function run_command_safe(array $command_parts, &$retval = DONT_CARE, $log_nonzero_exitcode = true): bool
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Why not

Suggested change
function run_command_safe(array $command_parts, &$retval = DONT_CARE, $log_nonzero_exitcode = true): bool
function run_command_safe(array $command_parts, ?int &$retval = null, $log_nonzero_exitcode = true): bool

and just always assing to retval? What's the benefit of the don't care thingy?

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This is what I had before but then you cannot distinguish between not passing anything or passing a "freshly created" variable anymore. See also #3156 (comment)

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I don't think I understand: why do we want to distinguish? But if you thought about it, I'm fine with it of course.

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I thought it did break for compile errors, but when I just tried again to verify, it doesn't break. Probably I was holding it wrong before.

{
if (empty($command_parts)) {
logmsg(LOG_WARNING, "Need at least the command that should be called.");
$retval = -1;
return false;
}

$command = implode(' ', array_map('dj_escapeshellarg', $command_parts));

logmsg(LOG_DEBUG, "Executing command: $command");
system($command, $retval_local);
if ($retval !== DONT_CARE) $retval = $retval_local;

Check failure on line 319 in judge/judgedaemon.main.php

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Inline control structures are not allowed

if ($retval_local !== 0) {
if ($log_nonzero_exitcode) {
logmsg(LOG_WARNING, "Command failed with exit code $retval_local: $command");
}
return false;
}

return true;
}

// Fetches a new executable from database if not cached already, and runs build script to compile executable.
// Returns an array with
// - absolute path to run script
Expand Down Expand Up @@ -354,12 +389,10 @@
$execrunjurypath = $execbuilddir . '/runjury';
if (!is_dir($execdir) || !file_exists($execdeploypath) ||
($combined_run_compare && file_get_contents(LIBJUDGEDIR . '/run-interactive.sh')!==file_get_contents($execrunpath))) {
system('rm -rf ' . dj_escapeshellarg($execdir) . ' ' . dj_escapeshellarg($execbuilddir), $retval);
if ($retval !== 0) {
if (!run_command_safe(['rm', '-rf', $execdir, $execbuilddir])) {
disable('judgehost', 'hostname', $myhost, "Deleting '$execdir' or '$execbuilddir' was unsuccessful.");
}
system('mkdir -p ' . dj_escapeshellarg($execbuilddir), $retval);
if ($retval !== 0) {
if (!run_command_safe(['mkdir', '-p', $execbuilddir])) {
disable('judgehost', 'hostname', $myhost, "Could not create directory '$execbuilddir'");
}

Expand Down Expand Up @@ -469,8 +502,7 @@
putenv('SCRIPTMEMLIMIT=' . djconfig_get_value('script_memory_limit'));
putenv('SCRIPTFILELIMIT=' . djconfig_get_value('script_filesize_limit'));

system(LIBJUDGEDIR . '/build_executable.sh ' . dj_escapeshellarg($execdir), $retval);
if ($retval !== 0) {
if (!run_command_safe([LIBJUDGEDIR . '/build_executable.sh', $execdir])) {
return [null, "Failed to build executable in $execdir.", "$execdir/build.log"];
}
chmod($execrunpath, 0755);
Expand Down Expand Up @@ -531,7 +563,11 @@
exit(1);
}

$myhost = trim(`hostname | cut -d . -f 1`);
$hostname = gethostname();
if ($hostname === false) {
error("Could not determine hostname.");
}
$myhost = explode('.', $hostname)[0];
if (isset($options['daemonid'])) {
if (preg_match('/^\d+$/', $options['daemonid'])) {
$myhost = $myhost . "-" . $options['daemonid'];
Expand Down Expand Up @@ -662,9 +698,8 @@

// Check basic prerequisites for chroot at judgehost startup
logmsg(LOG_INFO, "🔏 Executing chroot script: '".CHROOT_SCRIPT." check'");
system(LIBJUDGEDIR.'/'.CHROOT_SCRIPT.' check', $retval);
if ($retval!==0) {
error("chroot validation check exited with exitcode $retval");
if (!run_command_safe([LIBJUDGEDIR.'/'.CHROOT_SCRIPT, 'check'])) {
error("chroot validation check failed");
}

foreach ($endpoints as $id => $endpoint) {
Expand Down Expand Up @@ -756,8 +791,7 @@
foreach ($candidateDirs as $d) {
$cnt++;
logmsg(LOG_INFO, " - deleting $d");
system('rm -rf ' . dj_escapeshellarg($d), $retval);
if ($retval !== 0) {
if (!run_command_safe(['rm', '-rf', $d])) {
logmsg(LOG_WARNING, "Deleting '$d' was unsuccessful.");
}
$after = disk_free_space(JUDGEDIR);
Expand Down Expand Up @@ -881,10 +915,7 @@
$judgeTask['judgetaskid']
);

$debug_cmd = implode(' ', array_map('dj_escapeshellarg',
[$runpath, $workdir, $tmpfile]));
system($debug_cmd, $retval);
if ($retval !== 0) {
if (!run_command_safe([$runpath, $workdir, $tmpfile])) {
disable('run_script', 'run_script_id', $judgeTask['run_script_id'], "Running '$runpath' failed.");
}

Expand Down Expand Up @@ -953,8 +984,7 @@
}


system('mkdir -p ' . dj_escapeshellarg("$workdir/compile"), $retval);
if ($retval !== 0) {
if (!run_command_safe(['mkdir', '-p', "$workdir/compile"])) {
error("Could not create '$workdir/compile'");
}

Expand All @@ -967,8 +997,7 @@
if ($lastWorkdir !== $workdir) {
// create chroot environment
logmsg(LOG_INFO, " 🔒 Executing chroot script: '".CHROOT_SCRIPT." start'");
system(LIBJUDGEDIR.'/'.CHROOT_SCRIPT.' start', $retval);
if ($retval!==0) {
if (!run_command_safe([LIBJUDGEDIR.'/'.CHROOT_SCRIPT, 'start'], $retval)) {
logmsg(LOG_ERR, "chroot script exited with exitcode $retval");
disable('judgehost', 'hostname', $myhost, "chroot script exited with exitcode $retval on $myhost");
continue;
Expand Down Expand Up @@ -1030,8 +1059,7 @@

// Create directory where to test submissions
$workdirpath = JUDGEDIR . "/$myhost/endpoint-$endpointID";
system('mkdir -p ' . dj_escapeshellarg("$workdirpath/testcase"), $retval);
if ($retval !== 0) {
if (!run_command_safe(['mkdir', '-p', "$workdirpath/testcase"])) {
error("Could not create $workdirpath");
}
chmod("$workdirpath/testcase", 0700);
Expand Down Expand Up @@ -1109,8 +1137,7 @@

// destroy chroot environment
logmsg(LOG_INFO, " 🔓 Executing chroot script: '".CHROOT_SCRIPT." stop'");
system(LIBJUDGEDIR.'/'.CHROOT_SCRIPT.' stop', $retval);
if ($retval!==0) {
if (!run_command_safe([LIBJUDGEDIR.'/'.CHROOT_SCRIPT, 'stop'], $retval)) {
logmsg(LOG_ERR, "chroot script exited with exitcode $retval");
disable('judgehost', 'hostname', $myhost, "chroot script exited with exitcode $retval on $myhost");
// Just continue here: even though we might continue a current
Expand All @@ -1120,9 +1147,8 @@
}

// Evict all contents of the workdir from the kernel fs cache
system(LIBJUDGEDIR . '/evict ' . dj_escapeshellarg($workdir), $retval);
if ($retval!==0) {
warning("evict script exited with exitcode $retval");
if (!run_command_safe([LIBJUDGEDIR . '/evict', $workdir])) {
warning("evict script failed, continuing gracefully");
}
}

Expand All @@ -1131,7 +1157,7 @@
string $workdir,
string $workdirpath,
array $compile_config,
string $cpuset_opt,
?string $daemonid,
int $output_storage_limit
): bool {
global $myhost, $EXITCODES;
Expand All @@ -1151,26 +1177,24 @@
$args = 'hostname=' . urlencode($myhost);
foreach (['compiler', 'runner'] as $type) {
if (isset($version_verification[$type . '_version_command'])) {
if (file_exists($version_output_file)) {
unlink($version_output_file);
}

$vcscript_content = $version_verification[$type . '_version_command'];
$vcscript = tempnam(TMPDIR, 'version_check-');
file_put_contents($vcscript, $vcscript_content);
chmod($vcscript, 0755);
$version_cmd = LIBJUDGEDIR . "/version_check.sh " .
implode(' ', array_map('dj_escapeshellarg', [
$vcscript,
$workdir,
]));

if (file_exists($version_output_file)) {
unlink($version_output_file);
}
system($version_cmd, $retval);
run_command_safe([LIBJUDGEDIR . "/version_check.sh", $vcscript, $workdir], $retval);

$versions[$type] = trim(file_get_contents($version_output_file));
if ($retval !== 0) {
$versions[$type] =
"Getting $type version failed with exit code $retval\n"
. $versions[$type];
}

unlink($vcscript);
}
if (isset($versions[$type])) {
Expand Down Expand Up @@ -1248,16 +1272,14 @@
}

// Compile the program.
$compile_cmd = LIBJUDGEDIR . "/compile.sh $cpuset_opt " .
implode(' ', array_map('dj_escapeshellarg', array_merge([
$execrunpath,
$workdir,
], $files)));
logmsg(LOG_DEBUG, "Compile command: ".$compile_cmd);
system($compile_cmd, $retval);
if ($retval!==0) {
warning("compile script exited with exitcode $retval");
$compile_command_parts = [LIBJUDGEDIR . '/compile.sh'];
if (isset($daemonid)) {
$compile_command_parts[] = '-n';
$compile_command_parts[] = $daemonid;
}
array_push($compile_command_parts, $execrunpath, $workdir, ...$files);
// Note that the $retval is handled further down after reading/writing metadata.
run_command_safe($compile_command_parts, $retval, log_nonzero_exitcode: false);

$compile_output = '';
if (is_readable($workdir . '/compile.out')) {
Expand Down Expand Up @@ -1358,7 +1380,7 @@
}

$workdir = judging_directory($workdirpath, $judgeTask);
$compile_success = compile($judgeTask, $workdir, $workdirpath, $compile_config, $cpuset_opt, $output_storage_limit);
$compile_success = compile($judgeTask, $workdir, $workdirpath, $compile_config, $options['daemonid'] ?? null, $output_storage_limit);
if (!$compile_success) {
return false;
}
Expand Down Expand Up @@ -1460,37 +1482,39 @@
// after the first (note that $passCnt starts at 1).
if ($passCnt > 1) {
$prevPassdir = $testcasedir . '/' . ($passCnt - 1) . '/feedback';
system('cp -R ' . dj_escapeshellarg($prevPassdir) . ' ' . dj_escapeshellarg($passdir . '/'));
system('rm ' . dj_escapeshellarg($passdir . '/feedback/nextpass.in'));
run_command_safe(['cp', '-R', $prevPassdir, $passdir . '/']);
run_command_safe(['rm', $passdir . '/feedback/nextpass.in']);
}

// Copy program with all possible additional files to testcase
// dir. Use hardlinks to preserve space with big executables.
$programdir = $passdir . '/execdir';
system('mkdir -p ' . dj_escapeshellarg($programdir), $retval);
if ($retval!==0) {
if (!run_command_safe(['mkdir', '-p', $programdir])) {
error("Could not create directory '$programdir'");
}

foreach (glob("$workdir/compile/*") as $compile_file) {
system('cp -PRl ' . dj_escapeshellarg($compile_file) . ' ' . dj_escapeshellarg($programdir), $retval);
if ($retval!==0) {
if (!run_command_safe(['cp', '-PRl', $compile_file, $programdir])) {
error("Could not copy program to '$programdir'");
}
}

$timelimit_str = implode(':', $timelimit['cpu']) . ',' . implode(':', $timelimit['wall']);
$test_run_cmd = LIBJUDGEDIR . "/testcase_run.sh $cpuset_opt " .
implode(' ', array_map('dj_escapeshellarg', [
$input,
$output,
$timelimit_str,
$passdir,
$run_runpath,
$compare_runpath,
$compare_config['compare_args']
]));
system($test_run_cmd, $retval);
$run_command_parts = [LIBJUDGEDIR . '/testcase_run.sh'];
if (isset($options['daemonid'])) {
$run_command_parts[] = '-n';
$run_command_parts[] = $options['daemonid'];
}
array_push($run_command_parts,
$input,
$output,
$timelimit_str,
$passdir,
$run_runpath,
$compare_runpath,
$compare_config['compare_args']
);
run_command_safe($run_command_parts, $retval, log_nonzero_exitcode: false);

// What does the exitcode mean?
if (!isset($EXITCODES[$retval])) {
Expand Down
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