--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/libuv/test/test-process-title-threadsafe.c	Wed Jan 14 19:39:52 2026 -0800
@@ -0,0 +1,108 @@
+/* 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"
+
+#include <string.h>
+
+#ifdef __APPLE__
+# define NUM_ITERATIONS 5
+#else
+# define NUM_ITERATIONS 50
+#endif
+
+static const char* titles[] = {
+  "8L2NY0Kdj0XyNFZnmUZigIOfcWjyNr0SkMmUhKw99VLUsZFrvCQQC3XIRfNR8pjyMjXObllled",
+  "jUAcscJN49oLSN8GdmXj2Wo34XX2T2vp2j5khfajNQarlOulp57cE130yiY53ipJFnPyTn5i82",
+  "9niCI5icXGFS72XudhXqo5alftmZ1tpE7B3cwUmrq0CCDjC84FzBNB8XAHqvpNQfI2QAQG6ztT",
+  "n8qXVXuG6IEHDpabJgTEiwtpY6LHMZ8MgznnMpdHARu5EywufA6hcBaQfetb0YhEsK0ykDd7JU"
+};
+
+static void getter_thread_body(void* arg) {
+  uv_sem_t* getter_sem;
+  char buffer[512];
+  size_t len;
+
+  getter_sem = arg;
+
+  while (UV_EAGAIN == uv_sem_trywait(getter_sem)) {
+    ASSERT_OK(uv_get_process_title(buffer, sizeof(buffer)));
+
+    /* The maximum size of the process title on some platforms depends on
+     * the total size of the argv vector. It's therefore possible to read
+     * back a title that's shorter than what we submitted.
+     */
+    len = strlen(buffer);
+    ASSERT_GT(len, 0);
+
+    ASSERT(
+      0 == strncmp(buffer, titles[0], len) ||
+      0 == strncmp(buffer, titles[1], len) ||
+      0 == strncmp(buffer, titles[2], len) ||
+      0 == strncmp(buffer, titles[3], len));
+
+    uv_sleep(0);
+  }
+}
+
+
+static void setter_thread_body(void* arg) {
+  int i;
+
+  for (i = 0; i < NUM_ITERATIONS; i++) {
+    ASSERT_OK(uv_set_process_title(titles[0]));
+    ASSERT_OK(uv_set_process_title(titles[1]));
+    ASSERT_OK(uv_set_process_title(titles[2]));
+    ASSERT_OK(uv_set_process_title(titles[3]));
+  }
+}
+
+
+TEST_IMPL(process_title_threadsafe) {
+  uv_thread_t setter_threads[4];
+  uv_thread_t getter_thread;
+  uv_sem_t getter_sem;
+  int i;
+
+#if defined(__sun) || defined(__CYGWIN__) || defined(__MSYS__) || \
+    defined(__MVS__) || defined(__PASE__)
+  RETURN_SKIP("uv_(get|set)_process_title is not implemented.");
+#endif
+
+  ASSERT_OK(uv_set_process_title(titles[0]));
+
+  ASSERT_OK(uv_sem_init(&getter_sem, 0));
+  ASSERT_OK(uv_thread_create(&getter_thread, getter_thread_body, &getter_sem));
+
+  for (i = 0; i < (int) ARRAY_SIZE(setter_threads); i++)
+    ASSERT_OK(uv_thread_create(&setter_threads[i], setter_thread_body, NULL));
+
+  for (i = 0; i < (int) ARRAY_SIZE(setter_threads); i++)
+    ASSERT_OK(uv_thread_join(&setter_threads[i]));
+
+  uv_sem_post(&getter_sem);
+  ASSERT_OK(uv_thread_join(&getter_thread));
+  uv_sem_destroy(&getter_sem);
+
+  return 0;
+}