Modify the signatures of grpc_tcp_client_create_from_fd() and

grpc_tcp_client_create_from_prepared_fd(), and create grpc_fd after
connect(). Otherwise if we call connect() after epoll_wait() starts,
connect() will trigger a spurious EPOLLOUT|EPOLLHUP event.

src/core/lib/iomgr/tcp_client_posix.cc

@@ -247,21 +247,18 @@ static void on_writable(void* acp, grpc_error* error) {
 grpc_error* grpc_tcp_client_prepare_fd(const grpc_channel_args* channel_args,
                                        const grpc_resolved_address* addr,
                                        grpc_resolved_address* mapped_addr,
-                                       grpc_fd** fdobj) {
+                                       int* fd) {
   grpc_dualstack_mode dsmode;
-  int fd;
   grpc_error* error;
-  char* name;
-  char* addr_str;
-  *fdobj = nullptr;
+  *fd = -1;
   /* Use dualstack sockets where available. Set mapped to v6 or v4 mapped to
      v6. */
   if (!grpc_sockaddr_to_v4mapped(addr, mapped_addr)) {
     /* addr is v4 mapped to v6 or v6. */
     memcpy(mapped_addr, addr, sizeof(*mapped_addr));
   }
   error =
-      grpc_create_dualstack_socket(mapped_addr, SOCK_STREAM, 0, &dsmode, &fd);
+      grpc_create_dualstack_socket(mapped_addr, SOCK_STREAM, 0, &dsmode, fd);
   if (error != GRPC_ERROR_NONE) {
     return error;
   }
@@ -271,29 +268,32 @@ grpc_error* grpc_tcp_client_prepare_fd(const grpc_channel_args* channel_args,
       memcpy(mapped_addr, addr, sizeof(*mapped_addr));
     }
   }
-  if ((error = prepare_socket(mapped_addr, fd, channel_args)) !=
+  if ((error = prepare_socket(mapped_addr, *fd, channel_args)) !=
       GRPC_ERROR_NONE) {
     return error;
   }
-  addr_str = grpc_sockaddr_to_uri(mapped_addr);
-  gpr_asprintf(&name, "tcp-client:%s", addr_str);
-  *fdobj = grpc_fd_create(fd, name, true);
-  gpr_free(name);
-  gpr_free(addr_str);
   return GRPC_ERROR_NONE;
 }
 
 void grpc_tcp_client_create_from_prepared_fd(
-    grpc_pollset_set* interested_parties, grpc_closure* closure, grpc_fd* fdobj,
+    grpc_pollset_set* interested_parties, grpc_closure* closure, const int fd,
     const grpc_channel_args* channel_args, const grpc_resolved_address* addr,
     grpc_millis deadline, grpc_endpoint** ep) {
-  const int fd = grpc_fd_wrapped_fd(fdobj);
   int err;
   async_connect* ac;
   do {
     err = connect(fd, reinterpret_cast<const grpc_sockaddr*>(addr->addr),
                   addr->len);
   } while (err < 0 && errno == EINTR);
+
+  char* name;
+  char* addr_str;
+  addr_str = grpc_sockaddr_to_uri(addr);
+  gpr_asprintf(&name, "tcp-client:%s", addr_str);
+  grpc_fd* fdobj = grpc_fd_create(fd, name, true);
+  gpr_free(name);
+  gpr_free(addr_str);
+
   if (err >= 0) {
     char* addr_str = grpc_sockaddr_to_uri(addr);
     *ep = grpc_tcp_client_create_from_fd(fdobj, channel_args, addr_str);
@@ -340,15 +340,15 @@ static void tcp_connect(grpc_closure* closure, grpc_endpoint** ep,
                         const grpc_resolved_address* addr,
                         grpc_millis deadline) {
   grpc_resolved_address mapped_addr;
-  grpc_fd* fdobj = nullptr;
+  int fd = -1;
   grpc_error* error;
   *ep = nullptr;
   if ((error = grpc_tcp_client_prepare_fd(channel_args, addr, &mapped_addr,
-                                          &fdobj)) != GRPC_ERROR_NONE) {
+                                          &fd)) != GRPC_ERROR_NONE) {
     grpc_core::ExecCtx::Run(DEBUG_LOCATION, closure, error);
     return;
   }
-  grpc_tcp_client_create_from_prepared_fd(interested_parties, closure, fdobj,
+  grpc_tcp_client_create_from_prepared_fd(interested_parties, closure, fd,
                                           channel_args, &mapped_addr, deadline,
                                           ep);
 }

src/core/lib/iomgr/tcp_client_posix.h

@@ -35,33 +35,33 @@
 grpc_endpoint* grpc_tcp_client_create_from_fd(
     grpc_fd* fd, const grpc_channel_args* channel_args, const char* addr_str);
 
-/* Return a configured, unbound, unconnected TCP client grpc_fd.
+/* Return a configured, unbound, unconnected TCP client fd.
 
    channel_args: may contain custom settings for the fd
    addr: the destination address
    mapped_addr: out parameter. addr mapped to an address appropriate to the
      type of socket FD created. For example, if addr is IPv4 and dual stack
      sockets are available, mapped_addr will be an IPv4-mapped IPv6 address
-   fdobj: out parameter. The new FD
+   fd: out parameter. The new FD
    Returns: error, if any. Out parameters are not set on error
 */
 grpc_error* grpc_tcp_client_prepare_fd(const grpc_channel_args* channel_args,
                                        const grpc_resolved_address* addr,
                                        grpc_resolved_address* mapped_addr,
-                                       grpc_fd** fdobj);
+                                       int* fd);
 
-/* Connect a configured TCP client grpc_fd.
+/* Connect a configured TCP client fd.
 
    interested_parties: a set of pollsets that would be interested in this
      connection being established (in order to continue their work
    closure: called when complete. On success, *ep will be set.
-   fdobj: an FD returned from grpc_tcp_client_prepare_fd(). Ownership is taken
+   fd: an FD returned from grpc_tcp_client_prepare_fd().
    channel_args: may contain custom settings for the endpoint
    deadline: connection deadline
    ep: out parameter. Set before closure is called if successful
 */
 void grpc_tcp_client_create_from_prepared_fd(
-    grpc_pollset_set* interested_parties, grpc_closure* closure, grpc_fd* fdobj,
+    grpc_pollset_set* interested_parties, grpc_closure* closure, const int fd,
     const grpc_channel_args* channel_args, const grpc_resolved_address* addr,
     grpc_millis deadline, grpc_endpoint** ep);