Improve error messages for failed TCP/IP connections without ext-sockets

src/TcpConnector.php

@@ -99,14 +99,27 @@ public function connect($uri)
                 // The following hack looks like the only way to
                 // detect connection refused errors with PHP's stream sockets.
                 if (false === \stream_socket_get_name($stream, true)) {
-                    // actual socket errno and errstr can only be retrieved when ext-sockets is available (see tests)
+                    // If we reach this point, we know the connection is dead, but we don't know the underlying error condition.
                     // @codeCoverageIgnoreStart
                     if (\function_exists('socket_import_stream')) {
+                        // actual socket errno and errstr can be retrieved with ext-sockets on PHP 5.4+
                         $socket = \socket_import_stream($stream);
                         $errno = \socket_get_option($socket, \SOL_SOCKET, \SO_ERROR);
                         $errstr = \socket_strerror($errno);
+                    } elseif (\PHP_OS === 'Linux') {
+                        // Linux reports socket errno and errstr again when trying to write to the dead socket.
+                        // Suppress error reporting to get error message below and close dead socket before rejecting.
+                        // This is only known to work on Linux, Mac and Windows are known to not support this.
+                        @\fwrite($stream, \PHP_EOL);
+                        $error = \error_get_last();
+
+                        // fwrite(): send of 2 bytes failed with errno=111 Connection refused
+                        \preg_match('/errno=(\d+) (.+)/', $error['message'], $m);
+                        $errno = isset($m[1]) ? (int) $m[1] : 0;
+                        $errstr = isset($m[2]) ? $m[2] : $error['message'];
                     } else {
-                        $errno = \defined('SOCKET_ECONNREFUSED') ? \SOCKET_ECONNRESET : 111;
+                        // Not on Linux and ext-sockets not available? Too bad.
+                        $errno = \defined('SOCKET_ECONNREFUSED') ? \SOCKET_ECONNREFUSED : 111;
                         $errstr = 'Connection refused?';
                     }
                     // @codeCoverageIgnoreEnd

tests/TcpConnectorTest.php

@@ -103,21 +103,21 @@ public function connectionToTcpServerShouldFailIfFileDescriptorsAreExceeded()
     /** @test */
     public function connectionToInvalidNetworkShouldFailWithUnreachableError()
     {
-        if (!defined('SOCKET_ENETUNREACH') || !function_exists('socket_import_stream')) {
-            $this->markTestSkipped('Test requires ext-socket on PHP 5.4+');
+        if (PHP_OS !== 'Linux' && !function_exists('socket_import_stream')) {
+            $this->markTestSkipped('Test requires either Linux or ext-sockets on PHP 5.4+');
         }
 
+        $enetunreach = defined('SOCKET_ENETUNREACH') ? SOCKET_ENETUNREACH : 101;
+
         // try to find an unreachable network by trying a couple of private network addresses
-        $errno = 0; $errstr = '';
-        for ($i = 0; $i < 20; ++$i) {
+        $errno = 0;
+        $errstr = '';
+        for ($i = 0; $i < 20 && $errno !== $enetunreach; ++$i) {
             $address = 'tcp://192.168.' . mt_rand(0, 255) . '.' . mt_rand(1, 254) . ':8123';
             $client = @stream_socket_client($address, $errno, $errstr, 0.1 * $i);
-            if ($errno === SOCKET_ENETUNREACH) {
-                break;
-            }
         }
-        if ($client || $errno !== SOCKET_ENETUNREACH) {
-            $this->markTestSkipped('Expected error ' . SOCKET_ENETUNREACH . ' but got ' . $errno . ' (' . $errstr . ') for ' . $address);
+        if ($client || $errno !== $enetunreach) {
+            $this->markTestSkipped('Expected error ' . $enetunreach . ' but got ' . $errno . ' (' . $errstr . ') for ' . $address);
         }
 
         $loop = Factory::create();
@@ -127,8 +127,8 @@ public function connectionToInvalidNetworkShouldFailWithUnreachableError()
 
         $this->setExpectedException(
             'RuntimeException',
-            'Connection to ' . $address . ' failed: ' . socket_strerror(SOCKET_ENETUNREACH),
-            SOCKET_ENETUNREACH
+            'Connection to ' . $address . ' failed: ' . (function_exists('socket_strerror') ? socket_strerror($enetunreach) : 'Network is unreachable'),
+            $enetunreach
         );
         Block\await($promise, $loop, self::TIMEOUT);
     }