--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/libuv/test/test-fs-copyfile.c	Wed Jan 14 19:39:52 2026 -0800
@@ -0,0 +1,232 @@
+/* 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.
+ */
+
+#include "uv.h"
+#include "task.h"
+
+#if defined(__unix__) || defined(__POSIX__) || \
+    defined(__APPLE__) || defined(__sun) || \
+    defined(_AIX) || defined(__MVS__) || \
+    defined(__HAIKU__) || defined(__QNX__)
+#include <unistd.h> /* unlink, etc. */
+#else
+# include <direct.h>
+# include <io.h>
+# define unlink _unlink
+#endif
+
+static const char fixture[] = "test/fixtures/load_error.node";
+static const char dst[] = "test_file_dst";
+static int result_check_count;
+
+
+static void fail_cb(uv_fs_t* req) {
+  FATAL("fail_cb should not have been called");
+}
+
+static void handle_result(uv_fs_t* req) {
+  uv_fs_t stat_req;
+  uint64_t size;
+  uint64_t mode;
+  uint64_t uid;
+  uint64_t gid;
+  int r;
+
+  ASSERT_EQ(req->fs_type, UV_FS_COPYFILE);
+  ASSERT_OK(req->result);
+
+  /* Verify that the file size and mode are the same. */
+  r = uv_fs_stat(NULL, &stat_req, req->path, NULL);
+  ASSERT_OK(r);
+  size = stat_req.statbuf.st_size;
+  mode = stat_req.statbuf.st_mode;
+  uid = stat_req.statbuf.st_uid;
+  gid = stat_req.statbuf.st_gid;
+  uv_fs_req_cleanup(&stat_req);
+  r = uv_fs_stat(NULL, &stat_req, dst, NULL);
+  ASSERT_OK(r);
+  ASSERT_EQ(stat_req.statbuf.st_size, size);
+  ASSERT_EQ(stat_req.statbuf.st_mode, mode);
+  ASSERT_EQ(stat_req.statbuf.st_uid, uid);
+  ASSERT_EQ(stat_req.statbuf.st_gid, gid);
+  uv_fs_req_cleanup(&stat_req);
+  uv_fs_req_cleanup(req);
+  result_check_count++;
+}
+
+
+static void touch_file(const char* name, unsigned int size) {
+  uv_file file;
+  uv_fs_t req;
+  uv_buf_t buf;
+  int r;
+  unsigned int i;
+
+  r = uv_fs_open(NULL, &req, name,
+                 UV_FS_O_WRONLY | UV_FS_O_CREAT | UV_FS_O_TRUNC,
+                 S_IWUSR | S_IRUSR, NULL);
+  uv_fs_req_cleanup(&req);
+  ASSERT_GE(r, 0);
+  file = r;
+
+  buf = uv_buf_init("a", 1);
+
+  /* Inefficient but simple. */
+  for (i = 0; i < size; i++) {
+    r = uv_fs_write(NULL, &req, file, &buf, 1, i, NULL);
+    uv_fs_req_cleanup(&req);
+    ASSERT_GE(r, 0);
+  }
+
+  r = uv_fs_close(NULL, &req, file, NULL);
+  uv_fs_req_cleanup(&req);
+  ASSERT_OK(r);
+}
+
+
+TEST_IMPL(fs_copyfile) {
+  const char src[] = "test_file_src";
+  uv_loop_t* loop;
+  uv_fs_t req;
+  int r;
+
+  loop = uv_default_loop();
+
+  /* Fails with EINVAL if bad flags are passed. */
+  r = uv_fs_copyfile(NULL, &req, src, dst, -1, NULL);
+  ASSERT_EQ(r, UV_EINVAL);
+  uv_fs_req_cleanup(&req);
+
+  /* Fails with ENOENT if source does not exist. */
+  unlink(src);
+  unlink(dst);
+  r = uv_fs_copyfile(NULL, &req, src, dst, 0, NULL);
+  ASSERT_EQ(req.result, UV_ENOENT);
+  ASSERT_EQ(r, UV_ENOENT);
+  uv_fs_req_cleanup(&req);
+  /* The destination should not exist. */
+  r = uv_fs_stat(NULL, &req, dst, NULL);
+  ASSERT(r);
+  uv_fs_req_cleanup(&req);
+
+  /* Succeeds if src and dst files are identical. */
+  touch_file(src, 12);
+  r = uv_fs_copyfile(NULL, &req, src, src, 0, NULL);
+  ASSERT_OK(r);
+  uv_fs_req_cleanup(&req);
+  /* Verify that the src file did not get truncated. */
+  r = uv_fs_stat(NULL, &req, src, NULL);
+  ASSERT_OK(r);
+  ASSERT_EQ(12, req.statbuf.st_size);
+  uv_fs_req_cleanup(&req);
+  unlink(src);
+
+  /* Copies file synchronously. Creates new file. */
+  unlink(dst);
+  r = uv_fs_copyfile(NULL, &req, fixture, dst, 0, NULL);
+  ASSERT_OK(r);
+  handle_result(&req);
+
+  /* Copies a file of size zero. */
+  unlink(dst);
+  touch_file(src, 0);
+  r = uv_fs_copyfile(NULL, &req, src, dst, 0, NULL);
+  ASSERT_OK(r);
+  handle_result(&req);
+
+  /* Copies file synchronously. Overwrites existing file. */
+  r = uv_fs_copyfile(NULL, &req, fixture, dst, 0, NULL);
+  ASSERT_OK(r);
+  handle_result(&req);
+
+  /* Fails to overwrites existing file. */
+  ASSERT_OK(uv_fs_chmod(NULL, &req, dst, 0644, NULL));
+  uv_fs_req_cleanup(&req);
+  r = uv_fs_copyfile(NULL, &req, fixture, dst, UV_FS_COPYFILE_EXCL, NULL);
+  ASSERT_EQ(r, UV_EEXIST);
+  uv_fs_req_cleanup(&req);
+
+  /* Truncates when an existing destination is larger than the source file. */
+  ASSERT_OK(uv_fs_chmod(NULL, &req, dst, 0644, NULL));
+  uv_fs_req_cleanup(&req);
+  touch_file(src, 1);
+  r = uv_fs_copyfile(NULL, &req, src, dst, 0, NULL);
+  ASSERT_OK(r);
+  handle_result(&req);
+
+  /* Copies a larger file. */
+  unlink(dst);
+  touch_file(src, 4096 * 2);
+  r = uv_fs_copyfile(NULL, &req, src, dst, 0, NULL);
+  ASSERT_OK(r);
+  handle_result(&req);
+  unlink(src);
+
+  /* Copies file asynchronously */
+  unlink(dst);
+  r = uv_fs_copyfile(loop, &req, fixture, dst, 0, handle_result);
+  ASSERT_OK(r);
+  ASSERT_EQ(5, result_check_count);
+  uv_run(loop, UV_RUN_DEFAULT);
+  ASSERT_EQ(6, result_check_count);
+  /* Ensure file is user-writable (not copied from src). */
+  ASSERT_OK(uv_fs_chmod(NULL, &req, dst, 0644, NULL));
+  uv_fs_req_cleanup(&req);
+
+  /* If the flags are invalid, the loop should not be kept open */
+  unlink(dst);
+  r = uv_fs_copyfile(loop, &req, fixture, dst, -1, fail_cb);
+  ASSERT_EQ(r, UV_EINVAL);
+  uv_run(loop, UV_RUN_DEFAULT);
+
+  /* Copies file using UV_FS_COPYFILE_FICLONE. */
+  unlink(dst);
+  r = uv_fs_copyfile(NULL, &req, fixture, dst, UV_FS_COPYFILE_FICLONE, NULL);
+  ASSERT_OK(r);
+  handle_result(&req);
+
+  /* Copies file using UV_FS_COPYFILE_FICLONE_FORCE. */
+  unlink(dst);
+  r = uv_fs_copyfile(NULL, &req, fixture, dst, UV_FS_COPYFILE_FICLONE_FORCE,
+                     NULL);
+  ASSERT_LE(r, 0);
+
+  if (r == 0)
+    handle_result(&req);
+
+#ifndef _WIN32
+  /* Copying respects permissions/mode. */
+  unlink(dst);
+  touch_file(dst, 0);
+  chmod(dst, S_IRUSR|S_IRGRP|S_IROTH); /* Sets file mode to 444 (read-only). */
+  r = uv_fs_copyfile(NULL, &req, fixture, dst, 0, NULL);
+  /* On IBMi PASE, qsecofr users can overwrite read-only files */
+# ifndef __PASE__
+  ASSERT_EQ(req.result, UV_EACCES);
+  ASSERT_EQ(r, UV_EACCES);
+# endif
+  uv_fs_req_cleanup(&req);
+#endif
+
+  unlink(dst); /* Cleanup */
+  MAKE_VALGRIND_HAPPY(loop);
+  return 0;
+}