unix: fix reopened fd bug

When fd is closed and new one (with the same number) is opened inside
kqueue/epoll/port loop's callback - stale events might invoke callbacks
on wrong watchers.

Check if watcher was changed after invocation and invalidate all events
with the same fd.

fix #826

build.mk

@@ -114,6 +114,7 @@ TESTS= \
 	test/test-tcp-bind6-error.o \
 	test/test-tcp-bind-error.o \
 	test/test-tcp-close.o \
+	test/test-tcp-close-accept.o \
 	test/test-tcp-close-while-connecting.o \
 	test/test-tcp-connect6-error.o \
 	test/test-tcp-connect-error-after-write.o \

checksparse.sh

@@ -133,6 +133,7 @@ test/test-stdio-over-pipes.c
 test/test-tcp-bind-error.c
 test/test-tcp-bind6-error.c
 test/test-tcp-close-while-connecting.c
+test/test-tcp-close-accept.c
 test/test-tcp-close.c
 test/test-tcp-connect-error-after-write.c
 test/test-tcp-connect-error.c

src/unix/core.c

@@ -595,20 +595,33 @@ static unsigned int next_power_of_two(unsigned int val) {
 
 static void maybe_resize(uv_loop_t* loop, unsigned int len) {
   uv__io_t** watchers;
+  void* fake_watcher_list;
+  void* fake_watcher_count;
   unsigned int nwatchers;
   unsigned int i;
 
   if (len <= loop->nwatchers)
     return;
 
-  nwatchers = next_power_of_two(len);
+  nwatchers = next_power_of_two(len + 2) - 2;
-  watchers = realloc(loop->watchers, nwatchers * sizeof(loop->watchers[0]));
+  watchers = realloc(loop->watchers,
+                     (nwatchers + 2) * sizeof(loop->watchers[0]));
 
   if (watchers == NULL)
     abort();
 
+  /* Copy watchers, preserving fake one in the end */
+  if (loop->watchers == NULL) {
+    fake_watcher_list = watchers[loop->nwatchers];
+    fake_watcher_count = watchers[loop->nwatchers + 1];
+  } else {
+    fake_watcher_list = NULL;
+    fake_watcher_count = NULL;
+  }
   for (i = loop->nwatchers; i < nwatchers; i++)
     watchers[i] = NULL;
+  watchers[nwatchers] = fake_watcher_list;
+  watchers[nwatchers + 1] = fake_watcher_count;
 
   loop->watchers = watchers;
   loop->nwatchers = nwatchers;
@@ -700,6 +713,9 @@ void uv__io_stop(uv_loop_t* loop, uv__io_t* w, unsigned int events) {
 void uv__io_close(uv_loop_t* loop, uv__io_t* w) {
   uv__io_stop(loop, w, UV__POLLIN | UV__POLLOUT);
   ngx_queue_remove(&w->pending_queue);
+
+  /* Remove stale events for this file descriptor */
+  uv__platform_invalidate_fd(loop, w->fd);
 }
 
 

src/unix/darwin.c

@@ -102,6 +102,25 @@ void uv__platform_loop_delete(uv_loop_t* loop) {
 }
 
 
+void uv__platform_invalidate_fd(uv_loop_t* loop, int fd) {
+  struct kevent* events;
+  uintptr_t i;
+  uintptr_t nfds;
+
+  assert(loop->watchers != NULL);
+
+  events = (struct kevent*) loop->watchers[loop->nwatchers];
+  nfds = (uintptr_t) loop->watchers[loop->nwatchers + 1];
+  if (events == NULL)
+    return;
+
+  /* Invalidate events with same file descriptor */
+  for (i = 0; i < nfds; i++)
+    if ((int) events[i].ident == fd)
+      events[i].ident = -1;
+}
+
+
 static void uv__cf_loop_runner(void* arg) {
   uv_loop_t* loop;
 

src/unix/internal.h

@@ -183,6 +183,7 @@ uint64_t uv__hrtime(void);
 int uv__kqueue_init(uv_loop_t* loop);
 int uv__platform_loop_init(uv_loop_t* loop, int default_loop);
 void uv__platform_loop_delete(uv_loop_t* loop);
+void uv__platform_invalidate_fd(uv_loop_t* loop, int fd);
 
 /* various */
 void uv__async_close(uv_async_t* handle);

src/unix/kqueue.c

@@ -162,11 +162,18 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
 
     nevents = 0;
 
+    assert(loop->watchers != NULL);
+    loop->watchers[loop->nwatchers] = (void*) events;
+    loop->watchers[loop->nwatchers + 1] = (void*) (uintptr_t) nfds;
     for (i = 0; i < nfds; i++) {
       ev = events + i;
       fd = ev->ident;
       w = loop->watchers[fd];
 
+      /* Skip invalidated events, see uv__platform_invalidate_fd */
+      if (fd == -1)
+        continue;
+
       if (w == NULL) {
         /* File descriptor that we've stopped watching, disarm it. */
         /* TODO batch up */
@@ -227,6 +234,8 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
       w->cb(loop, w, revents);
       nevents++;
     }
+    loop->watchers[loop->nwatchers] = NULL;
+    loop->watchers[loop->nwatchers + 1] = NULL;
 
     if (nevents != 0) {
       if (nfds == ARRAY_SIZE(events) && --count != 0) {

src/unix/linux-core.c

@@ -97,6 +97,25 @@ void uv__platform_loop_delete(uv_loop_t* loop) {
 }
 
 
+void uv__platform_invalidate_fd(uv_loop_t* loop, int fd) {
+  struct uv__epoll_event* events;
+  uintptr_t i;
+  uintptr_t nfds;
+
+  assert(loop->watchers != NULL);
+
+  events = (struct uv__epoll_event*) loop->watchers[loop->nwatchers];
+  nfds = (uintptr_t) loop->watchers[loop->nwatchers + 1];
+  if (events == NULL)
+    return;
+
+  /* Invalidate events with same file descriptor */
+  for (i = 0; i < nfds; i++)
+    if ((int) events[i].data == fd)
+      events[i].data = -1;
+}
+
+
 void uv__io_poll(uv_loop_t* loop, int timeout) {
   struct uv__epoll_event events[1024];
   struct uv__epoll_event* pe;
@@ -189,10 +208,17 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
 
     nevents = 0;
 
+    assert(loop->watchers != NULL);
+    loop->watchers[loop->nwatchers] = (void*) events;
+    loop->watchers[loop->nwatchers + 1] = (void*) (uintptr_t) nfds;
     for (i = 0; i < nfds; i++) {
       pe = events + i;
       fd = pe->data;
 
+      /* Skip invalidated events, see uv__platform_invalidate_fd */
+      if (fd == -1)
+        continue;
+
       assert(fd >= 0);
       assert((unsigned) fd < loop->nwatchers);
 
@@ -238,6 +264,8 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
         nevents++;
       }
     }
+    loop->watchers[loop->nwatchers] = NULL;
+    loop->watchers[loop->nwatchers + 1] = NULL;
 
     if (nevents != 0) {
       if (nfds == ARRAY_SIZE(events) && --count != 0) {

src/unix/sunos.c

@@ -87,6 +87,25 @@ void uv__platform_loop_delete(uv_loop_t* loop) {
 }
 
 
+void uv__platform_invalidate_fd(uv_loop_t* loop, int fd) {
+  struct port_event* events;
+  uintptr_t i;
+  uintptr_t nfds;
+
+  assert(loop->watchers != NULL);
+
+  events = (struct port_event*) loop->watchers[loop->nwatchers];
+  nfds = (uintptr_t) loop->watchers[loop->nwatchers + 1];
+  if (events == NULL)
+    return;
+
+  /* Invalidate events with same file descriptor */
+  for (i = 0; i < nfds; i++)
+    if ((int) events[i].portev_object == fd)
+      events[i].portev_object = -1;
+}
+
+
 void uv__io_poll(uv_loop_t* loop, int timeout) {
   struct port_event events[1024];
   struct port_event* pe;
@@ -173,10 +192,17 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
 
     nevents = 0;
 
+    assert(loop->watchers != NULL);
+    loop->watchers[loop->nwatchers] = (void*) events;
+    loop->watchers[loop->nwatchers + 1] = (void*) (uintptr_t) nfds;
     for (i = 0; i < nfds; i++) {
       pe = events + i;
       fd = pe->portev_object;
 
+      /* Skip invalidated events, see uv__platform_invalidate_fd */
+      if (fd == -1)
+        continue;
+
       assert(fd >= 0);
       assert((unsigned) fd < loop->nwatchers);
 
@@ -193,6 +219,8 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
       if (w->pevents != 0 && ngx_queue_empty(&w->watcher_queue))
         ngx_queue_insert_tail(&loop->watcher_queue, &w->watcher_queue);
     }
+    loop->watchers[loop->nwatchers] = NULL;
+    loop->watchers[loop->nwatchers + 1] = NULL;
 
     if (nevents != 0) {
       if (nfds == ARRAY_SIZE(events) && --count != 0) {

test/test-list.h

@@ -64,6 +64,7 @@ TEST_DECLARE   (tcp_connect_error_fault)
 TEST_DECLARE   (tcp_connect_timeout)
 TEST_DECLARE   (tcp_close_while_connecting)
 TEST_DECLARE   (tcp_close)
+TEST_DECLARE   (tcp_close_accept)
 TEST_DECLARE   (tcp_flags)
 TEST_DECLARE   (tcp_write_to_half_open_connection)
 TEST_DECLARE   (tcp_unexpected_read)
@@ -298,6 +299,7 @@ TASK_LIST_START
   TEST_ENTRY  (tcp_connect_timeout)
   TEST_ENTRY  (tcp_close_while_connecting)
   TEST_ENTRY  (tcp_close)
+  TEST_ENTRY  (tcp_close_accept)
   TEST_ENTRY  (tcp_flags)
   TEST_ENTRY  (tcp_write_to_half_open_connection)
   TEST_ENTRY  (tcp_unexpected_read)

test/test-tcp-close-accept.c

@@ -0,0 +1,177 @@
+/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "uv.h"
+#include "task.h"
+
+#include <stdio.h>
+#include <string.h>
+
+static struct sockaddr_in addr;
+static uv_tcp_t tcp_server;
+static uv_tcp_t tcp_outgoing[2];
+static uv_tcp_t tcp_incoming[ARRAY_SIZE(tcp_outgoing)];
+static uv_connect_t connect_reqs[ARRAY_SIZE(tcp_outgoing)];
+static uv_tcp_t tcp_check;
+static uv_connect_t tcp_check_req;
+static uv_write_t write_reqs[ARRAY_SIZE(tcp_outgoing)];
+static unsigned int got_connections;
+static unsigned int close_cb_called;
+static unsigned int write_cb_called;
+static unsigned int read_cb_called;
+
+static void close_cb(uv_handle_t* handle) {
+  close_cb_called++;
+}
+
+static void write_cb(uv_write_t* req, int status) {
+  ASSERT(status == 0);
+  write_cb_called++;
+}
+
+static void connect_cb(uv_connect_t* req, int status) {
+  unsigned int i;
+  uv_buf_t buf;
+  uv_stream_t* outgoing;
+
+  if (req == &tcp_check_req) {
+    ASSERT(status != 0);
+
+    /* Close check and incoming[0], time to finish test */
+    uv_close((uv_handle_t*) &tcp_incoming[0], close_cb);
+    uv_close((uv_handle_t*) &tcp_check, close_cb);
+    return;
+  }
+
+  ASSERT(status == 0);
+  ASSERT(connect_reqs <= req);
+  ASSERT(req <= connect_reqs + ARRAY_SIZE(connect_reqs));
+  i = req - connect_reqs;
+
+  buf = uv_buf_init("x", 1);
+  outgoing = (uv_stream_t*) &tcp_outgoing[i];
+  ASSERT(0 == uv_write(&write_reqs[i], outgoing, &buf, 1, write_cb));
+}
+
+static uv_buf_t alloc_cb(uv_handle_t* handle, size_t suggested_size) {
+  static char buf[1];
+
+  return uv_buf_init(buf, sizeof(buf));
+}
+
+static void read_cb(uv_stream_t* stream, ssize_t nread, uv_buf_t b) {
+  uv_loop_t* loop;
+  unsigned int i;
+
+  /* Only first stream should receive read events */
+  ASSERT(stream == (uv_stream_t*) &tcp_incoming[0]);
+  ASSERT(0 == uv_read_stop(stream));
+  ASSERT(1 == nread);
+
+  loop = stream->loop;
+  read_cb_called++;
+
+  /* Close all active incomings, except current one */
+  for (i = 1; i < got_connections; i++)
+    uv_close((uv_handle_t*) &tcp_incoming[i], close_cb);
+
+  /* Create new fd that should be one of the closed incomings */
+  ASSERT(0 == uv_tcp_init(loop, &tcp_check));
+  ASSERT(0 == uv_tcp_connect(&tcp_check_req, &tcp_check, addr, connect_cb));
+  ASSERT(0 == uv_read_start((uv_stream_t*) &tcp_check, alloc_cb, read_cb));
+
+  /* Close server, so no one will connect to it */
+  uv_close((uv_handle_t*) &tcp_server, close_cb);
+}
+
+static void connection_cb(uv_stream_t* server, int status) {
+  unsigned int i;
+  uv_tcp_t* incoming;
+
+  ASSERT(server == (uv_stream_t*) &tcp_server);
+
+  /* Ignore tcp_check connection */
+  if (got_connections == ARRAY_SIZE(tcp_incoming))
+    return;
+
+  /* Accept everyone */
+  incoming = &tcp_incoming[got_connections++];
+  ASSERT(0 == uv_tcp_init(server->loop, incoming));
+  ASSERT(0 == uv_accept(server, (uv_stream_t*) incoming));
+
+  if (got_connections != ARRAY_SIZE(tcp_incoming))
+    return;
+
+  /* Once all clients are accepted - start reading */
+  for (i = 0; i < ARRAY_SIZE(tcp_incoming); i++) {
+    incoming = &tcp_incoming[i];
+    ASSERT(0 == uv_read_start((uv_stream_t*) incoming, alloc_cb, read_cb));
+  }
+}
+
+TEST_IMPL(tcp_close_accept) {
+  unsigned int i;
+  uv_loop_t* loop;
+  uv_tcp_t* client;
+
+  /*
+   * A little explanation of what goes on below:
+   *
+   * We'll create server and connect to it using two clients, each writing one
+   * byte once connected.
+   *
+   * When all clients will be accepted by server - we'll start reading from them
+   * and, on first client's first byte, will close second client and server.
+   * After that, we'll immediately initiate new connection to server using
+   * tcp_check handle (thus, reusing fd from second client).
+   *
+   * In this situation uv__io_poll()'s event list should still contain read
+   * event for second client, and, if not cleaned up properly, `tcp_check` will
+   * receive stale event of second incoming and invoke `connect_cb` with zero
+   * status.
+   */
+
+  loop = uv_default_loop();
+  addr = uv_ip4_addr("0.0.0.0", TEST_PORT);
+
+  ASSERT(0 == uv_tcp_init(loop, &tcp_server));
+  ASSERT(0 == uv_tcp_bind(&tcp_server, addr));
+  ASSERT(0 == uv_listen((uv_stream_t*) &tcp_server,
+                        ARRAY_SIZE(tcp_outgoing),
+                        connection_cb));
+
+  for (i = 0; i < ARRAY_SIZE(tcp_outgoing); i++) {
+    client = tcp_outgoing + i;
+
+    ASSERT(0 == uv_tcp_init(loop, client));
+    ASSERT(0 == uv_tcp_connect(&connect_reqs[i], client, addr, connect_cb));
+  }
+
+  uv_run(loop, UV_RUN_DEFAULT);
+
+  ASSERT(ARRAY_SIZE(tcp_outgoing) == got_connections);
+  ASSERT((ARRAY_SIZE(tcp_outgoing) + 2) == close_cb_called);
+  ASSERT(ARRAY_SIZE(tcp_outgoing) == write_cb_called);
+  ASSERT(1 == read_cb_called);
+
+  MAKE_VALGRIND_HAPPY();
+  return 0;
+}

uv.gyp

@@ -335,6 +335,7 @@
         'test/test-tcp-bind-error.c',
         'test/test-tcp-bind6-error.c',
         'test/test-tcp-close.c',
+        'test/test-tcp-close-accept.c',
         'test/test-tcp-close-while-connecting.c',
         'test/test-tcp-connect-error-after-write.c',
         'test/test-tcp-shutdown-after-write.c',