Add Thread#native_thread_id [Feature #17853]

test/ruby/test_thread.rb

@@ -1334,6 +1334,27 @@ q.pop
     assert_equal("foo", c.new {Thread.current.name}.value, bug12290)
   end
 
+  def test_thread_native_thread_id
+    skip "don't support native_thread_id" unless (Thread.main.native_thread_id rescue nil)
+    assert_instance_of Integer, Thread.main.native_thread_id
+
+    th1 = Thread.start{sleep}
+
+    # newly created thread which doesn't run yet returns nil or integer
+    assert_include [NilClass, Integer], th1.native_thread_id.class
+
+    Thread.pass until th1.stop?
+
+    # After a thread starts (and execute `sleep`), it returns native_thread_id
+    assert_instance_of Integer, th1.native_thread_id
+
+    th1.wakeup
+    Thread.pass while th1.alive?
+
+    # dead thread returns nil
+    assert_nil th1.native_thread_id
+  end
+
   def test_thread_interrupt_for_killed_thread
     opts = { timeout: 5, timeout_error: nil }
 

thread.c

@@ -3402,6 +3402,36 @@ rb_thread_setname(VALUE thread, VALUE name)
     return name;
 }
 
+/*
+ * call-seq:
+ *   thr.native_thread_id   -> integer
+ *
+ * Return the native thread ID which is used by the Ruby thread.
+ *
+ * The ID depends on the OS. (not POSIX thread ID returned by pthread_self(3))
+ * * On Linux it is TID returned by gettid(2).
+ * * On macOS it is the system-wide unique integral ID of thread returned
+ *   by pthread_threadid_np(3).
+ * * On FreeBSD it is the unique integral ID of the thread returned by
+ *   pthread_getthreadid_np(3).
+ * * On Windows it is the thread identifier returned by GetThreadId().
+ * * On other platforms, it raises NotImplementedError.
+ *
+ * NOTE:
+ * If the thread is not associated yet or already deassociated with a native
+ * thread, it returns _nil_.
+ * If the Ruby implementation uses M:N thread model, the ID may change
+ * depending on the timing.
+ */
+
+static VALUE
+rb_thread_native_thread_id(VALUE thread)
+{
+    rb_thread_t *target_th = rb_thread_ptr(thread);
+    if (rb_threadptr_dead(target_th)) return Qnil;
+    return native_thread_native_thread_id(target_th);
+}
+
 /*
  * call-seq:
  *   thr.to_s -> string
@@ -5494,6 +5524,7 @@ Init_Thread(void)
 
     rb_define_method(rb_cThread, "name", rb_thread_getname, 0);
     rb_define_method(rb_cThread, "name=", rb_thread_setname, 1);
+    rb_define_method(rb_cThread, "native_thread_id", rb_thread_native_thread_id, 0);
     rb_define_method(rb_cThread, "to_s", rb_thread_to_s, 0);
     rb_define_alias(rb_cThread, "inspect", "to_s");
 

thread_pthread.c

@@ -34,6 +34,9 @@
 #if defined(__HAIKU__)
 #include <kernel/OS.h>
 #endif
+#ifdef __linux__
+#include <sys/syscall.h> /* for SYS_gettid */
+#endif
 #include <time.h>
 #include <signal.h>
 
@@ -659,11 +662,26 @@ Init_native_thread(rb_thread_t *th)
     posix_signal(SIGVTALRM, null_func);
 }
 
+#ifdef RB_THREAD_T_HAS_NATIVE_ID
+static int
+get_native_thread_id(void)
+{
+#ifdef __linux__
+    return (int)syscall(SYS_gettid);
+#elif defined(__FreeBSD__)
+    return pthread_getthreadid_np();
+#endif
+}
+#endif
+
 static void
 native_thread_init(rb_thread_t *th)
 {
     native_thread_data_t *nd = &th->native_thread_data;
 
+#ifdef RB_THREAD_T_HAS_NATIVE_ID
+    th->tid = get_native_thread_id();
+#endif
 #ifdef USE_UBF_LIST
     list_node_init(&nd->node.ubf);
 #endif
@@ -1708,6 +1726,25 @@ native_set_another_thread_name(rb_nativethread_id_t thread_id, VALUE name)
 #endif
 }
 
+static VALUE
+native_thread_native_thread_id(rb_thread_t *target_th)
+{
+#if !defined(RB_THREAD_T_HAS_NATIVE_ID) && !defined(__APPLE__)
+    rb_notimplement();
+#endif
+
+#ifdef RB_THREAD_T_HAS_NATIVE_ID
+    int tid = target_th->tid;
+    if (tid == 0) return Qnil;
+    return INT2FIX(tid);
+#elif defined(__APPLE__)
+    uint64_t tid;
+    int e = pthread_threadid_np(target_th->thread_id, &tid);
+    if (e != 0) rb_syserr_fail(e, "pthread_threadid_np");
+    return ULL2NUM((unsigned long long)tid);
+#endif
+}
+
 static void
 ubf_timer_invalidate(void)
 {

thread_win32.c

@@ -835,6 +835,14 @@ native_set_thread_name(rb_thread_t *th)
 {
 }
 
+static VALUE
+native_thread_native_thread_id(rb_thread_t *th)
+{
+    DWORD tid = GetThreadId(th->thread_id);
+    if (tid == 0) rb_sys_fail("GetThreadId");
+    return ULONG2NUM(tid);
+}
+
 #if USE_MJIT
 static unsigned long __stdcall
 mjit_worker(void *arg)

vm_core.h

@@ -942,6 +942,10 @@ struct rb_ext_config {
 
 typedef struct rb_ractor_struct rb_ractor_t;
 
+#if defined(__linux__) || defined(__FreeBSD__)
+# define RB_THREAD_T_HAS_NATIVE_ID
+#endif
+
 typedef struct rb_thread_struct {
     struct list_node lt_node; // managed by a ractor
     VALUE self;
@@ -963,6 +967,9 @@ typedef struct rb_thread_struct {
     rb_nativethread_id_t thread_id;
 #ifdef NON_SCALAR_THREAD_ID
     rb_thread_id_string_t thread_id_string;
+#endif
+#ifdef RB_THREAD_T_HAS_NATIVE_ID
+    int tid;
 #endif
     BITFIELD(enum rb_thread_status, status, 2);
     /* bit flags */