win, pipe: avoid synchronous pipe deadlocks

Add a thread that will interrupt uv_pipe_zero_readdile_thread_proc every half
second. This allows other processes to access the pipe without deadlocking

Ref: nodejs/node#10836

src/win/pipe.c

@@ -46,6 +46,9 @@ struct uv__ipc_queue_item_s {
 /* A zero-size buffer for use by uv_pipe_read */
 static char uv_zero_[] = "";
 
+/* To prevent deadlocks we will interrupt synchronous pipe read every 500 ms */
+#define PIPE_ZERO_READ_INTERRUPT_INTERVAL 500
+
 /* Null uv_buf_t */
 static const uv_buf_t uv_null_buf_ = { 0, NULL };
 
@@ -942,13 +945,33 @@ int uv_pipe_listen(uv_pipe_t* handle, int backlog, uv_connection_cb cb) {
 }
 
 
+static DWORD WINAPI uv__pipe_zero_read_interrupter(void* param) {
+  HANDLE thread;
+  int r;
+  thread = (HANDLE) param;
+  for (;;) {
+    r = WaitForSingleObject(thread, PIPE_ZERO_READ_INTERRUPT_INTERVAL);
+    if (r == WAIT_TIMEOUT) {
+      /* ReadFile thread is active - interrupt ReadFile to give other */
+      /* processes a chance to act upon pipe */
+      pCancelSynchronousIo(thread);
+    } else {
+      /* ReadFile thread has terminated - cleanup the handle and exit */
+      CloseHandle(thread);
+      return 0;
+    }
+  }
+}
+
+
 static DWORD WINAPI uv_pipe_zero_readfile_thread_proc(void* parameter) {
   int result;
   DWORD bytes;
   uv_read_t* req = (uv_read_t*) parameter;
   uv_pipe_t* handle = (uv_pipe_t*) req->data;
   uv_loop_t* loop = handle->loop;
   HANDLE hThread = NULL;
+  HANDLE hThreadForInterrupt = NULL;
   DWORD err;
   uv_mutex_t *m = &handle->pipe.conn.readfile_mutex;
 
@@ -965,6 +988,12 @@ static DWORD WINAPI uv_pipe_zero_readfile_thread_proc(void* parameter) {
     } else {
       hThread = NULL;
     }
+    DuplicateHandle(GetCurrentProcess(), GetCurrentThread(),
+                    GetCurrentProcess(), &hThreadForInterrupt,
+                    0, TRUE, DUPLICATE_SAME_ACCESS);
+    QueueUserWorkItem(uv__pipe_zero_read_interrupter,
+                      hThreadForInterrupt,
+                      WT_EXECUTEINLONGTHREAD);
     uv_mutex_unlock(m);
   }
 restart_readfile:

test/test-list.h

@@ -199,6 +199,9 @@ TEST_DECLARE   (pipe_ref4)
 TEST_DECLARE   (pipe_close_stdout_read_stdin)
 #endif
 TEST_DECLARE   (pipe_set_non_blocking)
+#ifdef _WIN32
+TEST_DECLARE   (pipe_open_read_pipe)
+#endif
 TEST_DECLARE   (process_ref)
 TEST_DECLARE   (has_ref)
 TEST_DECLARE   (active)
@@ -422,6 +425,9 @@ TASK_LIST_START
   TEST_ENTRY  (pipe_close_stdout_read_stdin)
 #endif
   TEST_ENTRY  (pipe_set_non_blocking)
+#ifdef _WIN32
+  TEST_ENTRY  (pipe_open_read_pipe)
+#endif
   TEST_ENTRY  (tty)
 #ifdef _WIN32
   TEST_ENTRY  (tty_raw)

test/test-pipe-open-read-pipe.c

@@ -0,0 +1,61 @@
+#include "uv.h"
+#include "task.h"
+
+#ifndef _WIN32
+TEST_IMPL(pipe_open_read_pipe) {
+  RETURN_SKIP("Test only for Windows.");
+}
+#else
+
+#define NAME_BUF_SIZE 32768
+#define CHILD_WAIT_TIMEOUT 1000
+
+void alloc_cb(uv_handle_t* handle, size_t suggested_size, uv_buf_t* buf) {
+  buf->base = malloc(suggested_size);
+  buf->len = suggested_size;
+}
+
+void read_cb(uv_stream_t* stream, ssize_t nread, const uv_buf_t* buf) {
+}
+
+void pipe_read_thread_proc(void* arg) {
+  uv_pipe_t* pipe = arg;
+  uv_read_start(pipe, alloc_cb, read_cb);
+  uv_run(uv_default_loop(), UV_RUN_DEFAULT);
+  FATAL("loop should not exit");
+}
+
+TEST_IMPL(pipe_open_read_pipe) {
+  int r, pipe_fd;
+  uv_thread_t pipe_read_thread;
+  uv_pipe_t uv_pipe, uv_reopen_pipe;
+  HANDLE stdin_read_pipe, stdin_write_pipe;
+  SECURITY_ATTRIBUTES sa_attr;
+
+  sa_attr.nLength = sizeof(SECURITY_ATTRIBUTES);
+  sa_attr.bInheritHandle = TRUE;
+  sa_attr.lpSecurityDescriptor = NULL;
+  r = CreatePipe(&stdin_read_pipe, &stdin_write_pipe, &sa_attr, 0);
+  ASSERT(r != 0);
+
+  r = uv_pipe_init(uv_default_loop(), &uv_pipe, 0);
+  ASSERT(r == 0);
+  pipe_fd = _open_osfhandle(stdin_read_pipe, 0);
+  r = uv_pipe_open(&uv_pipe, pipe_fd);
+  ASSERT(r == 0);
+
+  r = uv_thread_create(&pipe_read_thread, pipe_read_thread_proc, &uv_pipe);
+  ASSERT(r == 0);
+
+  /* Give uv_run some time to start */
+  uv_sleep(250);
+  /* Try to access the pipe again, in different loop */
+  uv_loop_t test_loop;
+  r = uv_loop_init(&test_loop);
+  ASSERT(r == 0);
+  r = uv_pipe_init(&test_loop, &uv_reopen_pipe, 0);
+  ASSERT(r == 0);
+  r = uv_pipe_open(&uv_reopen_pipe, pipe_fd);
+  return TEST_OK;
+}
+#endif

uv.gyp

@@ -388,6 +388,7 @@
         'test/test-pipe-server-close.c',
         'test/test-pipe-close-stdout-read-stdin.c',
         'test/test-pipe-set-non-blocking.c',
+        'test/test-pipe-open-read-pipe.c',
         'test/test-platform-output.c',
         'test/test-poll.c',
         'test/test-poll-close.c',