--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/libuv/test/test-poll-oob.c	Wed Jan 14 19:39:52 2026 -0800
@@ -0,0 +1,214 @@
+/* Copyright libuv project 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.
+ */
+
+#if !defined(_WIN32)
+
+#include "uv.h"
+#include "task.h"
+
+#include <errno.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+#include <string.h>
+
+static uv_tcp_t server_handle;
+static uv_tcp_t client_handle;
+static uv_tcp_t peer_handle;
+static uv_poll_t poll_req[2];
+static uv_idle_t idle;
+static uv_os_fd_t client_fd;
+static uv_os_fd_t server_fd;
+static int ticks;
+static const int kMaxTicks = 10;
+static int cli_pr_check = 0;
+static int cli_rd_check = 0;
+static int srv_rd_check = 0;
+
+static int got_eagain(void) {
+  return errno == EAGAIN
+      || errno == EINPROGRESS
+#ifdef EWOULDBLOCK
+      || errno == EWOULDBLOCK
+#endif
+      ;
+}
+
+static void idle_cb(uv_idle_t* idle) {
+  uv_sleep(100);
+  if (++ticks < kMaxTicks)
+    return;
+
+  uv_poll_stop(&poll_req[0]);
+  uv_poll_stop(&poll_req[1]);
+  uv_close((uv_handle_t*) &server_handle, NULL);
+  uv_close((uv_handle_t*) &client_handle, NULL);
+  uv_close((uv_handle_t*) &peer_handle, NULL);
+  uv_close((uv_handle_t*) idle, NULL);
+}
+
+static void poll_cb(uv_poll_t* handle, int status, int events) {
+  char buffer[5];
+  int n;
+  int fd;
+
+  ASSERT_OK(uv_fileno((uv_handle_t*)handle, &fd));
+  memset(buffer, 0, 5);
+
+  if (events & UV_PRIORITIZED) {
+    do
+      n = recv(client_fd, &buffer, 5, MSG_OOB);
+    while (n == -1 && errno == EINTR);
+    ASSERT(n >= 0 || errno != EINVAL);
+    cli_pr_check = 1;
+    ASSERT_OK(uv_poll_stop(&poll_req[0]));
+    ASSERT_OK(uv_poll_start(&poll_req[0],
+                            UV_READABLE | UV_WRITABLE,
+                            poll_cb));
+  }
+  if (events & UV_READABLE) {
+    if (fd == client_fd) {
+      do
+        n = recv(client_fd, &buffer, 5, 0);
+      while (n == -1 && errno == EINTR);
+      ASSERT(n >= 0 || errno != EINVAL);
+      if (cli_rd_check == 1) {
+        ASSERT_OK(strncmp(buffer, "world", n));
+        ASSERT_EQ(5, n);
+        cli_rd_check = 2;
+      }
+      if (cli_rd_check == 0) {
+        ASSERT_EQ(4, n);
+        ASSERT_OK(strncmp(buffer, "hello", n));
+        cli_rd_check = 1;
+        do {
+          do
+            n = recv(server_fd, &buffer, 5, 0);
+          while (n == -1 && errno == EINTR);
+          if (n > 0) {
+            ASSERT_EQ(5, n);
+            ASSERT_OK(strncmp(buffer, "world", n));
+            cli_rd_check = 2;
+          }
+        } while (n > 0);
+
+        ASSERT(got_eagain());
+      }
+    }
+    if (fd == server_fd) {
+      do
+        n = recv(server_fd, &buffer, 3, 0);
+      while (n == -1 && errno == EINTR);
+      ASSERT(n >= 0 || errno != EINVAL);
+      ASSERT_EQ(3, n);
+      ASSERT_OK(strncmp(buffer, "foo", n));
+      srv_rd_check = 1;
+      uv_poll_stop(&poll_req[1]);
+    }
+  }
+  if (events & UV_WRITABLE) {
+    do {
+      n = send(client_fd, "foo", 3, 0);
+    } while (n < 0 && errno == EINTR);
+    ASSERT_EQ(3, n);
+  }
+}
+
+static void connection_cb(uv_stream_t* handle, int status) {
+  int r;
+
+  ASSERT_OK(status);
+  ASSERT_OK(uv_accept(handle, (uv_stream_t*) &peer_handle));
+  ASSERT_OK(uv_fileno((uv_handle_t*) &peer_handle, &server_fd));
+  ASSERT_OK(uv_poll_init_socket(uv_default_loop(),
+                                &poll_req[0],
+                                client_fd));
+  ASSERT_OK(uv_poll_init_socket(uv_default_loop(),
+                                &poll_req[1],
+                                server_fd));
+  ASSERT_OK(uv_poll_start(&poll_req[0],
+                          UV_PRIORITIZED | UV_READABLE | UV_WRITABLE,
+                          poll_cb));
+  ASSERT_OK(uv_poll_start(&poll_req[1],
+                          UV_READABLE,
+                          poll_cb));
+  do {
+    r = send(server_fd, "hello", 5, MSG_OOB);
+  } while (r < 0 && errno == EINTR);
+  ASSERT_EQ(5, r);
+
+  do {
+    r = send(server_fd, "world", 5, 0);
+  } while (r < 0 && errno == EINTR);
+  ASSERT_EQ(5, r);
+
+  ASSERT_OK(uv_idle_start(&idle, idle_cb));
+}
+
+
+TEST_IMPL(poll_oob) {
+  struct sockaddr_in addr;
+  int r = 0;
+  uv_loop_t* loop;
+
+  ASSERT_OK(uv_ip4_addr("127.0.0.1", TEST_PORT, &addr));
+  loop = uv_default_loop();
+
+  ASSERT_OK(uv_tcp_init(loop, &server_handle));
+  ASSERT_OK(uv_tcp_init(loop, &client_handle));
+  ASSERT_OK(uv_tcp_init(loop, &peer_handle));
+  ASSERT_OK(uv_idle_init(loop, &idle));
+  ASSERT_OK(uv_tcp_bind(&server_handle, (const struct sockaddr*) &addr, 0));
+  ASSERT_OK(uv_listen((uv_stream_t*) &server_handle, 1, connection_cb));
+
+  /* Ensure two separate packets */
+  ASSERT_OK(uv_tcp_nodelay(&client_handle, 1));
+
+  client_fd = socket(PF_INET, SOCK_STREAM, 0);
+  ASSERT_GE(client_fd, 0);
+  do {
+    errno = 0;
+    r = connect(client_fd, (const struct sockaddr*)&addr, sizeof(addr));
+  } while (r == -1 && errno == EINTR);
+  ASSERT_OK(r);
+
+  ASSERT_OK(uv_run(loop, UV_RUN_DEFAULT));
+
+  ASSERT_EQ(ticks, kMaxTicks);
+
+  /* Did client receive the POLLPRI message */
+  ASSERT_EQ(1, cli_pr_check);
+  /* Did client receive the POLLIN message */
+  ASSERT_EQ(2, cli_rd_check);
+  /* Could we write with POLLOUT and did the server receive our POLLOUT message
+   * through POLLIN.
+   */
+  ASSERT_EQ(1, srv_rd_check);
+
+  MAKE_VALGRIND_HAPPY(loop);
+  return 0;
+}
+
+#else
+
+typedef int file_has_no_tests; /* ISO C forbids an empty translation unit. */
+
+#endif