unix: keep track of bound sockets sent via spawn

We use the UV_HANDLE_BOUND flag to mark a socket as bound to a
port. We need to do this for sockets that are sent from another
process as well as sockets that created by the process itself.
First check if the port number is non-zero. If yes then mark
it as bound.

PR-URL: https://github.com/libuv/libuv/pull/1348
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>

src/unix/tcp.c

@@ -28,15 +28,12 @@
 #include <errno.h>
 
 
-static int maybe_new_socket(uv_tcp_t* handle, int domain, int flags) {
+static int new_socket(uv_tcp_t* handle, int domain, unsigned long flags) {
+  struct sockaddr_storage saddr;
+  socklen_t slen;
   int sockfd;
   int err;
 
-  if (domain == AF_UNSPEC || uv__stream_fd(handle) != -1) {
-    handle->flags |= flags;
-    return 0;
-  }
-
   err = uv__socket(domain, SOCK_STREAM, 0);
   if (err < 0)
     return err;
@@ -48,10 +45,74 @@ static int maybe_new_socket(uv_tcp_t* handle, int domain, int flags) {
     return err;
   }
 
+  if (flags & UV_HANDLE_BOUND) {
+    /* Bind this new socket to an arbitrary port */
+    slen = sizeof(saddr);
+    memset(&saddr, 0, sizeof(saddr));
+    err = getsockname(uv__stream_fd(handle), (struct sockaddr*) &saddr, &slen);
+    if (err) {
+      uv__close(sockfd);
+      return err;
+    }
+
+    err = bind(uv__stream_fd(handle), (struct sockaddr*) &saddr, slen);
+    if (err) {
+      uv__close(sockfd);
+      return err;
+    }
+  }
+
   return 0;
 }
 
 
+static int maybe_new_socket(uv_tcp_t* handle, int domain, unsigned long flags) {
+  struct sockaddr_storage saddr;
+  socklen_t slen;
+
+  if (domain == AF_UNSPEC) {
+    handle->flags |= flags;
+    return 0;
+  }
+
+  if (uv__stream_fd(handle) != -1) {
+
+    if (flags & UV_HANDLE_BOUND) {
+
+      if (handle->flags & UV_HANDLE_BOUND) {
+        /* It is already bound to a port. */
+        handle->flags |= flags;
+        return 0;
+      }
+      
+      /* Query to see if tcp socket is bound. */
+      slen = sizeof(saddr);
+      memset(&saddr, 0, sizeof(saddr));
+      if (getsockname(uv__stream_fd(handle), (struct sockaddr*) &saddr, &slen))
+        return -errno;
+
+      if ((saddr.ss_family == AF_INET6 &&
+          ((struct sockaddr_in6*) &saddr)->sin6_port != 0) ||
+          (saddr.ss_family == AF_INET &&
+          ((struct sockaddr_in*) &saddr)->sin_port != 0)) {
+        /* Handle is already bound to a port. */
+        handle->flags |= flags;
+        return 0;
+      }
+
+      /* Bind to arbitrary port */
+      if (bind(uv__stream_fd(handle), (struct sockaddr*) &saddr, slen))
+        return -errno;
+    }
+
+    handle->flags |= flags;
+    return 0;
+  }
+
+  return new_socket(handle, domain, flags);
+}
+
+
 int uv_tcp_init_ex(uv_loop_t* loop, uv_tcp_t* tcp, unsigned int flags) {
   int domain;
 
@@ -260,6 +321,7 @@ int uv_tcp_getpeername(const uv_tcp_t* handle,
 
 int uv_tcp_listen(uv_tcp_t* tcp, int backlog, uv_connection_cb cb) {
   static int single_accept = -1;
+  unsigned long flags;
   int err;
 
   if (tcp->delayed_error)
@@ -273,30 +335,17 @@ int uv_tcp_listen(uv_tcp_t* tcp, int backlog, uv_connection_cb cb) {
   if (single_accept)
     tcp->flags |= UV_TCP_SINGLE_ACCEPT;
 
-  err = maybe_new_socket(tcp, AF_INET, UV_STREAM_READABLE);
-  if (err)
-    return err;
-
-#ifdef __MVS__
+  flags = UV_STREAM_READABLE;
+#if defined(__MVS__)
   /* on zOS the listen call does not bind automatically
      if the socket is unbound. Hence the manual binding to
      an arbitrary port is required to be done manually
   */
-
-  if (!(tcp->flags & UV_HANDLE_BOUND)) {
-    struct sockaddr_storage saddr;
-    socklen_t slen  = sizeof(saddr);
-    memset(&saddr, 0, sizeof(saddr));
-
-    if (getsockname(tcp->io_watcher.fd, (struct sockaddr*) &saddr, &slen))
-      return -errno;
-
-    if (bind(tcp->io_watcher.fd, (struct sockaddr*) &saddr, slen))
-      return -errno;
-
-    tcp->flags |= UV_HANDLE_BOUND;
-  }
-#endif
+  flags |= UV_HANDLE_BOUND;
+#endif  
+  err = maybe_new_socket(tcp, AF_INET, flags);
+  if (err)
+    return err;
 
   if (listen(tcp->io_watcher.fd, backlog))
     return -errno;

test/run-tests.c

@@ -43,6 +43,7 @@ int ipc_send_recv_helper(void);
 int ipc_helper_bind_twice(void);
 int stdio_over_pipes_helper(void);
 int spawn_stdin_stdout(void);
+int spawn_tcp_server_helper(void);
 
 static int maybe_run_test(int argc, char **argv);
 
@@ -111,6 +112,10 @@ static int maybe_run_test(int argc, char **argv) {
     return 1;
   }
 
+  if (strcmp(argv[1], "spawn_tcp_server_helper") == 0) {
+    return spawn_tcp_server_helper();
+  }
+
   if (strcmp(argv[1], "spawn_helper3") == 0) {
     char buffer[256];
     ASSERT(buffer == fgets(buffer, sizeof(buffer) - 1, stdin));

test/test-list.h

@@ -260,6 +260,7 @@ TEST_DECLARE   (spawn_closed_process_io)
 TEST_DECLARE   (spawn_reads_child_path)
 TEST_DECLARE   (spawn_inherit_streams)
 TEST_DECLARE   (spawn_quoted_path)
+TEST_DECLARE   (spawn_tcp_server)
 TEST_DECLARE   (fs_poll)
 TEST_DECLARE   (fs_poll_getpath)
 TEST_DECLARE   (kill)
@@ -743,6 +744,7 @@ TASK_LIST_START
   TEST_ENTRY  (spawn_reads_child_path)
   TEST_ENTRY  (spawn_inherit_streams)
   TEST_ENTRY  (spawn_quoted_path)
+  TEST_ENTRY  (spawn_tcp_server)
   TEST_ENTRY  (fs_poll)
   TEST_ENTRY  (fs_poll_getpath)
   TEST_ENTRY  (kill)

test/test-spawn.c

@@ -50,6 +50,7 @@ static size_t exepath_size = 1024;
 static char* args[5];
 static int no_term_signal;
 static int timer_counter;
+static uv_tcp_t tcp_server;
 
 #define OUTPUT_SIZE 1024
 static char output[OUTPUT_SIZE];
@@ -622,6 +623,81 @@ TEST_IMPL(spawn_stdio_greater_than_3) {
 }
 
 
+int spawn_tcp_server_helper(void) {
+  uv_tcp_t tcp;
+  uv_os_sock_t handle;
+  int r;
+
+  r = uv_tcp_init(uv_default_loop(), &tcp);
+  ASSERT(r == 0);
+
+#ifdef _WIN32
+  handle = _get_osfhandle(3);
+#else
+  handle = 3;
+#endif
+  r = uv_tcp_open(&tcp, handle);
+  ASSERT(r == 0);
+
+  /* Make sure that we can listen on a socket that was
+   * passed down from the parent process
+   */
+  r = uv_listen((uv_stream_t*)&tcp, SOMAXCONN, NULL);
+  ASSERT(r == 0);
+
+  return 1;
+}
+
+
+TEST_IMPL(spawn_tcp_server) {
+  uv_stdio_container_t stdio[4];
+  struct sockaddr_in addr;
+  int fd;
+  int r;
+
+  init_process_options("spawn_tcp_server_helper", exit_cb);
+
+  ASSERT(0 == uv_ip4_addr("127.0.0.1", TEST_PORT, &addr));
+
+  fd = -1;
+  r = uv_tcp_init_ex(uv_default_loop(), &tcp_server, AF_INET);
+  ASSERT(r == 0);
+  r = uv_tcp_bind(&tcp_server, (const struct sockaddr*) &addr, 0);
+  ASSERT(r == 0);
+#ifdef _WIN32
+  r = uv_fileno((uv_handle_t*)&tcp_server, &handle);
+  fd = _open_osfhandle((intptr_t) handle, 0);
+#else
+  r = uv_fileno((uv_handle_t*)&tcp_server, &fd);
+ #endif
+  ASSERT(r == 0);
+  ASSERT(fd > 0);
+
+  options.stdio = stdio;
+  options.stdio[0].flags = UV_INHERIT_FD;
+  options.stdio[0].data.fd = 0;
+  options.stdio[1].flags = UV_INHERIT_FD;
+  options.stdio[1].data.fd = 1;
+  options.stdio[2].flags = UV_INHERIT_FD;
+  options.stdio[2].data.fd = 2;
+  options.stdio[3].flags = UV_INHERIT_FD;
+  options.stdio[3].data.fd = fd;
+  options.stdio_count = 4;
+
+  r = uv_spawn(uv_default_loop(), &process, &options);
+  ASSERT(r == 0);
+
+  r = uv_run(uv_default_loop(), UV_RUN_DEFAULT);
+  ASSERT(r == 0);
+
+  ASSERT(exit_cb_called == 1);
+  ASSERT(close_cb_called == 1);
+
+  MAKE_VALGRIND_HAPPY();
+  return 0;
+}
+
+
 TEST_IMPL(spawn_ignored_stdio) {
   int r;