From 070557afc4ca83876b951fe090806b59e3867ae5 Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Thu, 6 Feb 2020 09:14:40 +0900
Subject: Distinguish signal and timeout [Bug #16608]

---
 thread_sync.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

(limited to 'thread_sync.c')

diff --git a/thread_sync.c b/thread_sync.c
index 894235e9e1..44290136b3 100644
--- a/thread_sync.c
+++ b/thread_sync.c
@@ -533,14 +533,15 @@ rb_mutex_wait_for(VALUE time)
 {
     rb_hrtime_t *rel = (rb_hrtime_t *)time;
     /* permit spurious check */
-    sleep_hrtime(GET_THREAD(), *rel, 0);
-    return Qnil;
+    if (sleep_hrtime(GET_THREAD(), *rel, 0)) return Qtrue;
+    return Qfalse;
 }
 
 VALUE
 rb_mutex_sleep(VALUE self, VALUE timeout)
 {
     struct timeval t;
+    VALUE woken = Qtrue;
 
     if (!NIL_P(timeout)) {
         t = rb_time_interval(timeout);
@@ -560,18 +561,19 @@ rb_mutex_sleep(VALUE self, VALUE timeout)
         }
         else {
             rb_hrtime_t rel = rb_timeval2hrtime(&t);
-            rb_ensure(rb_mutex_wait_for, (VALUE)&rel, mutex_lock_uninterruptible, self);
+            woken = rb_ensure(rb_mutex_wait_for, (VALUE)&rel, mutex_lock_uninterruptible, self);
         }
     }
 
     RUBY_VM_CHECK_INTS_BLOCKING(GET_EC());
+    if (!woken) return Qnil;
     time_t end = time(0) - beg;
     return TIMET2NUM(end);
 }
 
 /*
  * call-seq:
- *    mutex.sleep(timeout = nil)    -> number
+ *    mutex.sleep(timeout = nil)    -> number or nil
  *
  * Releases the lock and sleeps +timeout+ seconds if it is given and
  * non-nil or forever.  Raises +ThreadError+ if +mutex+ wasn't locked by
@@ -582,6 +584,8 @@ rb_mutex_sleep(VALUE self, VALUE timeout)
  *
  * Note that this method can wakeup without explicit Thread#wakeup call.
  * For example, receiving signal and so on.
+ *
+ * Returns the slept time in seconds if woken up, or +nil+ if timed out.
  */
 static VALUE
 mutex_sleep(int argc, VALUE *argv, VALUE self)
@@ -1483,6 +1487,8 @@ do_sleep(VALUE args)
  *
  * If +timeout+ is given, this method returns after +timeout+ seconds passed,
  * even if no other thread doesn't signal.
+ *
+ * Returns the slept result on +mutex+.
  */
 
 static VALUE
@@ -1502,9 +1508,7 @@ rb_condvar_wait(int argc, VALUE *argv, VALUE self)
     };
 
     list_add_tail(&cv->waitq, &sync_waiter.node);
-    rb_ensure(do_sleep, (VALUE)&args, delete_from_waitq, (VALUE)&sync_waiter);
-
-    return self;
+    return rb_ensure(do_sleep, (VALUE)&args, delete_from_waitq, (VALUE)&sync_waiter);
 }
 
 /*
-- 
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