aix, ibmi: handle server hang when remote sends TCP RST (#3482)

Workaround getsockname() not working for a TCP handle that has
received RST from the remote.

Co-authored-by: Jameson Nash <vtjnash@gmail.com>

CMakeLists.txt

@@ -574,6 +574,7 @@ if(LIBUV_BUILD_TESTS)
        test/test-tcp-open.c
        test/test-tcp-read-stop.c
        test/test-tcp-read-stop-start.c
+       test/test-tcp-rst.c
        test/test-tcp-shutdown-after-write.c
        test/test-tcp-try-write.c
        test/test-tcp-try-write-error.c

Makefile.am

@@ -266,6 +266,7 @@ test_run_tests_SOURCES = test/blackhole-server.c \
                          test/test-tcp-open.c \
                          test/test-tcp-read-stop.c \
                          test/test-tcp-read-stop-start.c \
+                         test/test-tcp-rst.c \
                          test/test-tcp-shutdown-after-write.c \
                          test/test-tcp-unexpected-read.c \
                          test/test-tcp-oob.c \

src/unix/internal.h

@@ -277,7 +277,6 @@ void uv__tcp_close(uv_tcp_t* handle);
 size_t uv__thread_stack_size(void);
 void uv__udp_close(uv_udp_t* handle);
 void uv__udp_finish_close(uv_udp_t* handle);
-uv_handle_type uv__handle_type(int fd);
 FILE* uv__open_file(const char* path);
 int uv__getpwuid_r(uv_passwd_t* pwd);
 int uv__search_path(const char* prog, char* buf, size_t* buflen);

src/unix/pipe.c

@@ -319,7 +319,7 @@ uv_handle_type uv_pipe_pending_type(uv_pipe_t* handle) {
   if (handle->accepted_fd == -1)
     return UV_UNKNOWN_HANDLE;
   else
-    return uv__handle_type(handle->accepted_fd);
+    return uv_guess_handle(handle->accepted_fd);
 }
 
 

src/unix/stream.c

@@ -964,49 +964,6 @@ static void uv__write_callbacks(uv_stream_t* stream) {
 }
 
 
-uv_handle_type uv__handle_type(int fd) {
-  struct sockaddr_storage ss;
-  socklen_t sslen;
-  socklen_t len;
-  int type;
-
-  memset(&ss, 0, sizeof(ss));
-  sslen = sizeof(ss);
-
-  if (getsockname(fd, (struct sockaddr*)&ss, &sslen))
-    return UV_UNKNOWN_HANDLE;
-
-  len = sizeof type;
-
-  if (getsockopt(fd, SOL_SOCKET, SO_TYPE, &type, &len))
-    return UV_UNKNOWN_HANDLE;
-
-  if (type == SOCK_STREAM) {
-#if defined(_AIX) || defined(__DragonFly__)
-    /* on AIX/DragonFly the getsockname call returns an empty sa structure
-     * for sockets of type AF_UNIX.  For all other types it will
-     * return a properly filled in structure.
-     */
-    if (sslen == 0)
-      return UV_NAMED_PIPE;
-#endif
-    switch (ss.ss_family) {
-      case AF_UNIX:
-        return UV_NAMED_PIPE;
-      case AF_INET:
-      case AF_INET6:
-        return UV_TCP;
-      }
-  }
-
-  if (type == SOCK_DGRAM &&
-      (ss.ss_family == AF_INET || ss.ss_family == AF_INET6))
-    return UV_UDP;
-
-  return UV_UNKNOWN_HANDLE;
-}
-
-
 static void uv__stream_eof(uv_stream_t* stream, const uv_buf_t* buf) {
   stream->flags |= UV_HANDLE_READ_EOF;
   stream->flags &= ~UV_HANDLE_READING;

src/unix/tty.c

@@ -331,7 +331,7 @@ int uv_tty_get_winsize(uv_tty_t* tty, int* width, int* height) {
 
 
 uv_handle_type uv_guess_handle(uv_file file) {
-  struct sockaddr sa;
+  struct sockaddr_storage ss;
   struct stat s;
   socklen_t len;
   int type;
@@ -342,8 +342,23 @@ uv_handle_type uv_guess_handle(uv_file file) {
   if (isatty(file))
     return UV_TTY;
 
-  if (fstat(file, &s))
+  if (fstat(file, &s)) {
+#if defined(__PASE__)
+    // On ibmi receiving RST from TCP instead of FIN immediately puts fd into
+    // an error state. fstat will return EINVAL, getsockname will also return
+    // EINVAL, even if sockaddr_storage is valid. (If file does not refer to a
+    // socket, ENOTSOCK is returned instead.)
+    // In such cases, we will permit the user to open the connection as uv_tcp
+    // still, so that the user can get immediately notified of the error in
+    // their read callback and close this fd.
+    len = sizeof(ss);
+    if (getsockname(file, (struct sockaddr*) &ss, &len)) {
+      if (errno == EINVAL)
+        return UV_TCP;
+    }
+#endif
     return UV_UNKNOWN_HANDLE;
+  }
 
   if (S_ISREG(s.st_mode))
     return UV_FILE;
@@ -357,16 +372,28 @@ uv_handle_type uv_guess_handle(uv_file file) {
   if (!S_ISSOCK(s.st_mode))
     return UV_UNKNOWN_HANDLE;
 
+  len = sizeof(ss);
+  if (getsockname(file, (struct sockaddr*) &ss, &len)) {
+#if defined(_AIX)
+    // On aix receiving RST from TCP instead of FIN immediately puts fd into
+    // an error state. In such case getsockname will return EINVAL, even if
+    // sockaddr_storage is valid.
+    // In such cases, we will permit the user to open the connection as uv_tcp
+    // still, so that the user can get immediately notified of the error in
+    // their read callback and close this fd.
+    if (errno == EINVAL) {
+      return UV_TCP;
+    }
+#endif
+    return UV_UNKNOWN_HANDLE;
+  }
+
   len = sizeof(type);
   if (getsockopt(file, SOL_SOCKET, SO_TYPE, &type, &len))
     return UV_UNKNOWN_HANDLE;
 
-  len = sizeof(sa);
-  if (getsockname(file, &sa, &len))
-    return UV_UNKNOWN_HANDLE;
-
   if (type == SOCK_DGRAM)
-    if (sa.sa_family == AF_INET || sa.sa_family == AF_INET6)
+    if (ss.ss_family == AF_INET || ss.ss_family == AF_INET6)
       return UV_UDP;
 
   if (type == SOCK_STREAM) {
@@ -379,9 +406,9 @@ uv_handle_type uv_guess_handle(uv_file file) {
       return UV_NAMED_PIPE;
 #endif /* defined(_AIX) || defined(__DragonFly__) */
 
-    if (sa.sa_family == AF_INET || sa.sa_family == AF_INET6)
+    if (ss.ss_family == AF_INET || ss.ss_family == AF_INET6)
       return UV_TCP;
-    if (sa.sa_family == AF_UNIX)
+    if (ss.ss_family == AF_UNIX)
       return UV_NAMED_PIPE;
   }
 

test/test-list.h

@@ -147,6 +147,7 @@ TEST_DECLARE   (tcp_write_to_half_open_connection)
 TEST_DECLARE   (tcp_unexpected_read)
 TEST_DECLARE   (tcp_read_stop)
 TEST_DECLARE   (tcp_read_stop_start)
+TEST_DECLARE   (tcp_rst)
 TEST_DECLARE   (tcp_bind6_error_addrinuse)
 TEST_DECLARE   (tcp_bind6_error_addrnotavail)
 TEST_DECLARE   (tcp_bind6_error_fault)
@@ -723,6 +724,9 @@ TASK_LIST_START
 
   TEST_ENTRY  (tcp_read_stop_start)
 
+  TEST_ENTRY  (tcp_rst)
+  TEST_HELPER (tcp_rst, tcp4_echo_server)
+
   TEST_ENTRY  (tcp_bind6_error_addrinuse)
   TEST_ENTRY  (tcp_bind6_error_addrnotavail)
   TEST_ENTRY  (tcp_bind6_error_fault)

test/test-tcp-rst.c

@@ -0,0 +1,111 @@
+/* Copyright libuv project and 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"
+
+static uv_tcp_t tcp;
+static uv_connect_t connect_req;
+static uv_shutdown_t shutdown_req;
+static uv_buf_t qbuf;
+static int called_alloc_cb;
+static int called_connect_cb;
+static int called_shutdown_cb;
+static int called_close_cb;
+
+
+static void close_cb(uv_handle_t* handle) {
+  ASSERT(handle == (uv_handle_t*) &tcp);
+  called_close_cb++;
+}
+
+
+static void alloc_cb(uv_handle_t* handle, size_t size, uv_buf_t* buf) {
+  buf->base = malloc(size);
+  buf->len = size;
+  called_alloc_cb++;
+}
+
+
+static void read_cb(uv_stream_t* t, ssize_t nread, const uv_buf_t* buf) {
+  ASSERT_PTR_EQ((uv_tcp_t*) t, &tcp);
+  ASSERT_EQ(nread, UV_ECONNRESET);
+
+  int fd;
+  ASSERT_EQ(0, uv_fileno((uv_handle_t*) t, &fd));
+  uv_handle_type type = uv_guess_handle(fd);
+  ASSERT_EQ(type, UV_TCP);
+
+  uv_close((uv_handle_t *) t, close_cb);
+  free(buf->base);
+}
+
+
+static void connect_cb(uv_connect_t *req, int status) {
+  ASSERT_EQ(status, 0);
+  ASSERT_PTR_EQ(req, &connect_req);
+
+  /* Start reading from the connection so we receive the RST in uv__read. */
+  ASSERT_EQ(0, uv_read_start((uv_stream_t*) &tcp, alloc_cb, read_cb));
+
+  /* Write 'QSH' to receive RST from the echo server. */
+  ASSERT_EQ(qbuf.len, uv_try_write((uv_stream_t*) &tcp, &qbuf, 1));
+
+  called_connect_cb++;
+  ASSERT_EQ(called_shutdown_cb, 0);
+}
+
+
+/*
+ * This test has a client which connects to the echo_server and receives TCP
+ * RST. Test checks that uv_guess_handle still works on a reset TCP handle.
+ */
+TEST_IMPL(tcp_rst) {
+#ifndef _WIN32
+  struct sockaddr_in server_addr;
+  int r;
+
+  qbuf.base = "QSH";
+  qbuf.len = 3;
+
+  ASSERT_EQ(0, uv_ip4_addr("127.0.0.1", TEST_PORT, &server_addr));
+  r = uv_tcp_init(uv_default_loop(), &tcp);
+  ASSERT_EQ(r, 0);
+
+  r = uv_tcp_connect(&connect_req,
+                     &tcp,
+                     (const struct sockaddr*) &server_addr,
+                     connect_cb);
+  ASSERT_EQ(r, 0);
+
+  uv_run(uv_default_loop(), UV_RUN_DEFAULT);
+
+  ASSERT_EQ(called_alloc_cb, 1);
+  ASSERT_EQ(called_connect_cb, 1);
+  ASSERT_EQ(called_shutdown_cb, 0);
+  ASSERT_EQ(called_close_cb, 1);
+
+  MAKE_VALGRIND_HAPPY();
+  return 0;
+#else
+  RETURN_SKIP("Unix only test");
+#endif
+}