unix,win: add UV_PIPE_NO_TRUNCATE flag (#4040)

Libuv's default behavior is to truncate long Unix socket paths. The flag
tells it to return an error instead.

Fixes: https://github.com/libuv/libuv/issues/4036

docs/src/pipe.rst

@@ -68,15 +68,18 @@ API
 
     Bind the pipe to a file path (Unix) or a name (Windows).
 
-    ``flags`` must be zero. Returns ``UV_EINVAL`` for unsupported flags
+    ``flags`` must be zero or ``UV_PIPE_NO_TRUNCATE``. Returns ``UV_EINVAL``
-    without performing the bind operation.
+    for unsupported flags without performing the bind operation.
 
     Supports Linux abstract namespace sockets. ``namelen`` must include
     the leading nul byte but not the trailing nul byte.
 
+    .. versionadded:: 1.46.0
+
     .. note::
         Paths on Unix get truncated to ``sizeof(sockaddr_un.sun_path)`` bytes,
-        typically between 92 and 108 bytes.
+        typically between 92 and 108 bytes, unless the ``UV_PIPE_NO_TRUNCATE``
+        flag is specified, in which case an ``UV_EINVAL`` error is returned.
 
 .. c:function:: void uv_pipe_connect(uv_connect_t* req, uv_pipe_t* handle, const char* name, uv_connect_cb cb)
 
@@ -95,15 +98,18 @@ API
 
     Connect to the Unix domain socket or the Windows named pipe.
 
-    ``flags`` must be zero. Returns ``UV_EINVAL`` for unsupported flags
+    ``flags`` must be zero or ``UV_PIPE_NO_TRUNCATE``. Returns ``UV_EINVAL``
-    without performing the connect operation.
+    for unsupported flags without performing the connect operation.
 
     Supports Linux abstract namespace sockets. ``namelen`` must include
     the leading nul byte but not the trailing nul byte.
 
+    .. versionadded:: 1.46.0
+
     .. note::
         Paths on Unix get truncated to ``sizeof(sockaddr_un.sun_path)`` bytes,
-        typically between 92 and 108 bytes.
+        typically between 92 and 108 bytes, unless the ``UV_PIPE_NO_TRUNCATE``
+        flag is specified, in which case an ``UV_EINVAL`` error is returned.
 
 .. c:function:: int uv_pipe_getsockname(const uv_pipe_t* handle, char* buffer, size_t* size)
 

include/uv.h

@@ -807,6 +807,10 @@ inline int uv_tty_set_mode(uv_tty_t* handle, int mode) {
 
 UV_EXTERN uv_handle_type uv_guess_handle(uv_file file);
 
+enum {
+  UV_PIPE_NO_TRUNCATE = 1u << 0
+};
+
 /*
  * uv_pipe_t is a subclass of uv_stream_t.
  *

src/unix/pipe.c

@@ -56,7 +56,7 @@ int uv_pipe_bind2(uv_pipe_t* handle,
 
   pipe_fname = NULL;
 
-  if (flags != 0)
+  if (flags & ~UV_PIPE_NO_TRUNCATE)
     return UV_EINVAL;
 
   if (name == NULL)
@@ -71,6 +71,10 @@ int uv_pipe_bind2(uv_pipe_t* handle,
     return UV_EINVAL;
 #endif
 
+  if (flags & UV_PIPE_NO_TRUNCATE)
+    if (namelen > sizeof(saddr.sun_path))
+      return UV_EINVAL;
+
   /* Truncate long paths. Documented behavior. */
   if (namelen > sizeof(saddr.sun_path))
     namelen = sizeof(saddr.sun_path);
@@ -221,7 +225,7 @@ int uv_pipe_connect2(uv_connect_t* req,
   int err;
   int r;
 
-  if (flags != 0)
+  if (flags & ~UV_PIPE_NO_TRUNCATE)
     return UV_EINVAL;
 
   if (name == NULL)
@@ -236,6 +240,10 @@ int uv_pipe_connect2(uv_connect_t* req,
     return UV_EINVAL;
 #endif
 
+  if (flags & UV_PIPE_NO_TRUNCATE)
+    if (namelen > sizeof(saddr.sun_path))
+      return UV_EINVAL;
+
   /* Truncate long paths. Documented behavior. */
   if (namelen > sizeof(saddr.sun_path))
     namelen = sizeof(saddr.sun_path);

src/win/pipe.c

@@ -706,7 +706,7 @@ int uv_pipe_bind2(uv_pipe_t* handle,
   int i, err, nameSize;
   uv_pipe_accept_t* req;
 
-  if (flags != 0) {
+  if (flags & ~UV_PIPE_NO_TRUNCATE) {
     return UV_EINVAL;
   }
 
@@ -722,6 +722,12 @@ int uv_pipe_bind2(uv_pipe_t* handle,
     return UV_EINVAL;
   }
 
+  if (flags & UV_PIPE_NO_TRUNCATE) {
+    if (namelen > 256) {
+      return UV_EINVAL;
+    }
+  }
+
   if (handle->flags & UV_HANDLE_BOUND) {
     return UV_EINVAL;
   }
@@ -859,7 +865,7 @@ int uv_pipe_connect2(uv_connect_t* req,
   HANDLE pipeHandle = INVALID_HANDLE_VALUE;
   DWORD duplex_flags;
 
-  if (flags != 0) {
+  if (flags & ~UV_PIPE_NO_TRUNCATE) {
     return UV_EINVAL;
   }
 
@@ -875,6 +881,12 @@ int uv_pipe_connect2(uv_connect_t* req,
     return UV_EINVAL;
   }
 
+  if (flags & UV_PIPE_NO_TRUNCATE) {
+    if (namelen > 256) {
+      return UV_EINVAL;
+    }
+  }
+
   UV_REQ_INIT(req, UV_CONNECT);
   req->handle = (uv_stream_t*) handle;
   req->cb = cb;

test/test-list.h

@@ -198,6 +198,7 @@ TEST_DECLARE   (pipe_connect_close_multiple)
 TEST_DECLARE   (pipe_connect_multiple)
 TEST_DECLARE   (pipe_listen_without_bind)
 TEST_DECLARE   (pipe_bind_or_listen_error_after_close)
+TEST_DECLARE   (pipe_overlong_path)
 TEST_DECLARE   (pipe_connect_bad_name)
 TEST_DECLARE   (pipe_connect_to_file)
 TEST_DECLARE   (pipe_connect_on_prepare)
@@ -799,6 +800,7 @@ TASK_LIST_START
   TEST_ENTRY  (pipe_connect_multiple)
   TEST_ENTRY  (pipe_listen_without_bind)
   TEST_ENTRY  (pipe_bind_or_listen_error_after_close)
+  TEST_ENTRY  (pipe_overlong_path)
   TEST_ENTRY  (pipe_getsockname)
   TEST_ENTRY  (pipe_getsockname_abstract)
   TEST_ENTRY  (pipe_getsockname_blocking)

test/test-pipe-bind-error.c

@@ -153,3 +153,27 @@ TEST_IMPL(pipe_bind_or_listen_error_after_close) {
   MAKE_VALGRIND_HAPPY(uv_default_loop());
   return 0;
 }
+
+TEST_IMPL(pipe_overlong_path) {
+  char path[512];
+  uv_pipe_t pipe;
+  uv_connect_t req;
+
+  memset(path, '@', sizeof(path));
+  ASSERT_OK(uv_pipe_init(uv_default_loop(), &pipe, 0));
+  ASSERT_EQ(UV_EINVAL,
+            uv_pipe_bind2(&pipe, path, sizeof(path), UV_PIPE_NO_TRUNCATE));
+  ASSERT_EQ(UV_EINVAL,
+            uv_pipe_connect2(&req,
+                             &pipe,
+                             path,
+                             sizeof(path),
+                             UV_PIPE_NO_TRUNCATE,
+                             (uv_connect_cb) abort));
+  uv_close((uv_handle_t*) &pipe, NULL);
+  ASSERT_OK(uv_run(uv_default_loop(), UV_RUN_DEFAULT));
+
+  MAKE_VALGRIND_HAPPY(uv_default_loop());
+  return 0;
+
+}