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bug #17276 [Process] Fix potential race condition (nicolas-grekas)

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This PR was merged into the 2.3 branch.

Discussion
----------

[Process] Fix potential race condition

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

As seen at https://travis-ci.org/symfony/symfony/jobs/100448880#L2768, ProcessTest::testRunProcessWithTimeout can create an infinite blocking situation.
I found two potential code paths that could be subject to a race condition. This fixes them.

Commits
-------

b114a85 [Process] Fix potential race condition
This commit is contained in:
Nicolas Grekas 2016-01-06 10:56:27 +01:00
commit 707d359c0c
2 changed files with 13 additions and 15 deletions
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16
src/Symfony/Component/Process/Process.php
View File

@ -651,8 +651,12 @@ class Process
} }
} }
$this->updateStatus(false); if ($this->isRunning()) {
if ($this->processInformation['running']) { if (isset($this->fallbackStatus['pid'])) {
unset($this->fallbackStatus['pid']);
return $this->stop(0, $signal);
}
$this->close(); $this->close();
} }
@ -1145,7 +1149,7 @@ class Process
*/ */
private function doSignal($signal, $throwException) private function doSignal($signal, $throwException)
{ {
if (!$this->isRunning()) { if (null === $pid = $this->getPid()) {
if ($throwException) { if ($throwException) {
throw new LogicException('Can not send signal on a non running process.'); throw new LogicException('Can not send signal on a non running process.');
} }
@ -1154,7 +1158,7 @@ class Process
} }
if ('\\' === DIRECTORY_SEPARATOR) { if ('\\' === DIRECTORY_SEPARATOR) {
exec(sprintf('taskkill /F /T /PID %d 2>&1', $this->getPid()), $output, $exitCode); exec(sprintf('taskkill /F /T /PID %d 2>&1', $pid), $output, $exitCode);
if ($exitCode && $this->isRunning()) { if ($exitCode && $this->isRunning()) {
if ($throwException) { if ($throwException) {
throw new RuntimeException(sprintf('Unable to kill the process (%s).', implode(' ', $output))); throw new RuntimeException(sprintf('Unable to kill the process (%s).', implode(' ', $output)));
@ -1166,8 +1170,8 @@ class Process
if (!$this->enhanceSigchildCompatibility || !$this->isSigchildEnabled()) { if (!$this->enhanceSigchildCompatibility || !$this->isSigchildEnabled()) {
$ok = @proc_terminate($this->process, $signal); $ok = @proc_terminate($this->process, $signal);
} elseif (function_exists('posix_kill')) { } elseif (function_exists('posix_kill')) {
$ok = @posix_kill($this->getPid(), $signal); $ok = @posix_kill($pid, $signal);
} elseif ($ok = proc_open(sprintf('kill -%d %d', $signal, $this->getPid()), array(2 => array('pipe', 'w')), $pipes)) { } elseif ($ok = proc_open(sprintf('kill -%d %d', $signal, $pid), array(2 => array('pipe', 'w')), $pipes)) {
$ok = false === fgets($pipes[2]); $ok = false === fgets($pipes[2]);
} }
if (!$ok) { if (!$ok) {

12
src/Symfony/Component/Process/Tests/ProcessTest.php
View File

@ -685,22 +685,16 @@ class ProcessTest extends \PHPUnit_Framework_TestCase
*/ */
public function testRunProcessWithTimeout() public function testRunProcessWithTimeout()
{ {
$timeout = 0.1; $process = $this->getProcess(self::$phpBin.' -r "sleep(30);"');
$process = $this->getProcess(self::$phpBin.' -r "sleep(1);"'); $process->setTimeout(0.1);
$process->setTimeout($timeout);
$start = microtime(true); $start = microtime(true);
try { try {
$process->run(); $process->run();
$this->fail('A RuntimeException should have been raised'); $this->fail('A RuntimeException should have been raised');
} catch (RuntimeException $e) { } catch (RuntimeException $e) {
} }
$duration = microtime(true) - $start;
if ('\\' !== DIRECTORY_SEPARATOR) { $this->assertLessThan(15, microtime(true) - $start);
// On Windows, timers are too transient
$maxDuration = $timeout + 2 * Process::TIMEOUT_PRECISION;
$this->assertLessThan($maxDuration, $duration);
}
throw $e; throw $e;
} }