[wing/wip/createpipe] namedpipeclient: fix race when waiting for the named pipe

[Ignacio Casal Quinteiro <icq src gnome org>]

commit e79aad42834b4eec20c054a6224b72256679fe0d
Author: Ignacio Casal Quinteiro <ignacio casal nice-software com>
Date:   Mon Sep 19 13:24:50 2016 +0200

    namedpipeclient: fix race when waiting for the named pipe
    
    In the time that we get that the pipe is ready when calling
    WaitnamedPipe and the time that we call CreateFile another
    named pipe pipe could have been connected and it will fail
    with ERROR_PIPE_BUSY, in this case we should retry to wait again.
    
    See: https://msdn.microsoft.com/es-es/library/windows/desktop/aa365592(v=vs.85).aspx

 wing/wingnamedpipeclient.c |   59 ++++++++++++++++++++++++-------------------
 1 files changed, 33 insertions(+), 26 deletions(-)
---
diff --git a/wing/wingnamedpipeclient.c b/wing/wingnamedpipeclient.c
index 1f17574..d19e2f0 100644
--- a/wing/wingnamedpipeclient.c
+++ b/wing/wingnamedpipeclient.c
@@ -182,8 +182,11 @@ wing_named_pipe_client_connect (WingNamedPipeClient  *client,
 
   pipe_namew = g_utf8_to_utf16 (pipe_name, -1, NULL, NULL, NULL);
 
-  if (WaitNamedPipeW (pipe_namew, priv->timeout))
+  while (TRUE)
     {
+      if (g_cancellable_set_error_if_cancelled (cancellable, error))
+        break;
+
       handle = CreateFileW (pipe_namew,
                             GENERIC_READ | GENERIC_WRITE,
                             FILE_SHARE_READ | FILE_SHARE_WRITE,
@@ -192,45 +195,49 @@ wing_named_pipe_client_connect (WingNamedPipeClient  *client,
                             FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED,
                             NULL);
 
-      if (handle == INVALID_HANDLE_VALUE)
+      if (handle != INVALID_HANDLE_VALUE)
+        break;
+
+      if (GetLastError () != ERROR_PIPE_BUSY)
         {
           int errsv;
           gchar *err;
 
           errsv = GetLastError ();
           err = g_win32_error_message (errsv);
-          g_set_error_literal (error, G_IO_ERROR,
-                               g_io_error_from_win32_error (errsv),
-                               err);
+          g_set_error (error, G_IO_ERROR,
+                       g_io_error_from_win32_error (errsv),
+                       "Could not create file for named pipe '%s': %s",
+                       pipe_name, err);
           g_free (err);
-          goto end;
+          break;
         }
 
-      if (g_cancellable_set_error_if_cancelled (cancellable, error))
-          goto end;
+      if (!WaitNamedPipeW (pipe_namew, priv->timeout))
+        {
+          int errsv;
+          gchar *err;
 
-      connection = g_object_new (WING_TYPE_NAMED_PIPE_CONNECTION,
-                                 "pipe-name", pipe_name,
-                                 "handle", handle,
-                                 "close-handle", TRUE,
-                                 NULL);
-    }
-  else
-    {
-      int errsv;
-      gchar *err;
-
-      errsv = GetLastError ();
-      err = g_win32_error_message (errsv);
-      g_set_error_literal (error, G_IO_ERROR,
-                           g_io_error_from_win32_error (errsv),
-                           err);
-      g_free (err);
+          errsv = GetLastError ();
+          err = g_win32_error_message (errsv);
+          g_set_error (error, G_IO_ERROR,
+                       g_io_error_from_win32_error (errsv),
+                       "Failed to wait for named pipe '%s': %s",
+                       pipe_name, err);
+          g_free (err);
+          break;
+        }
     }
 
-end:
   g_free (pipe_namew);
 
+  if (handle != INVALID_HANDLE_VALUE)
+    connection = g_object_new (WING_TYPE_NAMED_PIPE_CONNECTION,
+                               "pipe-name", pipe_name,
+                               "handle", handle,
+                               "close-handle", TRUE,
+                               NULL);
+
   return connection;
 }