bug symfony#28689 [Process] fix locking of pipe files on Windows (nicolas-grekas)

This PR was merged into the 2.8 branch.

Discussion
----------

[Process] fix locking of pipe files on Windows

| Q             | A
| ------------- | ---
| Branch?       | 2.8
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | symfony#28655
| License       | MIT
| Doc PR        | -

Commits
-------

d64bd3b [Process] fix locking of pipe files on Windows

Author: fabpot

src/Symfony/Component/Process/Pipes/WindowsPipes.php

@@ -28,6 +28,7 @@ class WindowsPipes extends AbstractPipes
 {
     private $files = array();
     private $fileHandles = array();
+    private $lockHandles = array();
     private $readBytes = array(
         Process::STDOUT => 0,
         Process::STDERR => 0,
@@ -47,31 +48,33 @@ public function __construct($disableOutput, $input)
                 Process::STDOUT => Process::OUT,
                 Process::STDERR => Process::ERR,
             );
-            $tmpCheck = false;
             $tmpDir = sys_get_temp_dir();
             $lastError = 'unknown reason';
             set_error_handler(function ($type, $msg) use (&$lastError) { $lastError = $msg; });
             for ($i = 0;; ++$i) {
                 foreach ($pipes as $pipe => $name) {
                     $file = sprintf('%s\\sf_proc_%02X.%s', $tmpDir, $i, $name);
-                    if (file_exists($file) && !unlink($file)) {
-                        continue 2;
-                    }
-                    $h = fopen($file, 'xb');
-                    if (!$h) {
-                        $error = $lastError;
-                        if ($tmpCheck || $tmpCheck = unlink(tempnam(false, 'sf_check_'))) {
-                            continue;
-                        }
+
+                    if (!$h = fopen($file.'.lock', 'w')) {
                         restore_error_handler();
-                        throw new RuntimeException(sprintf('A temporary file could not be opened to write the process output: %s', $error));
+                        throw new RuntimeException(sprintf('A temporary file could not be opened to write the process output: %s', $lastError));
                     }
-                    if (!$h || !$this->fileHandles[$pipe] = fopen($file, 'rb')) {
+                    if (!flock($h, LOCK_EX | LOCK_NB)) {
                         continue 2;
                     }
-                    if (isset($this->files[$pipe])) {
-                        unlink($this->files[$pipe]);
+                    if (isset($this->lockHandles[$pipe])) {
+                        flock($this->lockHandles[$pipe], LOCK_UN);
+                        fclose($this->lockHandles[$pipe]);
                     }
+                    $this->lockHandles[$pipe] = $h;
+
+                    if (!fclose(fopen($file, 'w')) || !$h = fopen($file, 'r')) {
+                        flock($this->lockHandles[$pipe], LOCK_UN);
+                        fclose($this->lockHandles[$pipe]);
+                        unset($this->lockHandles[$pipe]);
+                        continue 2;
+                    }
+                    $this->fileHandles[$pipe] = $h;
                     $this->files[$pipe] = $file;
                 }
                 break;
@@ -85,7 +88,6 @@ public function __construct($disableOutput, $input)
     public function __destruct()
     {
         $this->close();
-        $this->removeFiles();
     }
 
     /**
@@ -145,8 +147,11 @@ public function readAndWrite($blocking, $close = false)
                 $read[$type] = $data;
             }
             if ($close) {
+                ftruncate($fileHandle, 0);
                 fclose($fileHandle);
-                unset($this->fileHandles[$type]);
+                flock($this->lockHandles[$type], LOCK_UN);
+                fclose($this->lockHandles[$type]);
+                unset($this->fileHandles[$type], $this->lockHandles[$type]);
             }
         }
 
@@ -167,10 +172,13 @@ public function areOpen()
     public function close()
     {
         parent::close();
-        foreach ($this->fileHandles as $handle) {
+        foreach ($this->fileHandles as $type => $handle) {
+            ftruncate($handle, 0);
             fclose($handle);
+            flock($this->lockHandles[$type], LOCK_UN);
+            fclose($this->lockHandles[$type]);
         }
-        $this->fileHandles = array();
+        $this->fileHandles = $this->lockHandles = array();
     }
 
     /**
@@ -185,17 +193,4 @@ public static function create(Process $process, $input)
     {
         return new static($process->isOutputDisabled(), $input);
     }
-
-    /**
-     * Removes temporary files.
-     */
-    private function removeFiles()
-    {
-        foreach ($this->files as $filename) {
-            if (file_exists($filename)) {
-                @unlink($filename);
-            }
-        }
-        $this->files = array();
-    }
 }