[PATCH v12 2/2] ntdll: Fix the return value of NtDelayExecution.

[William Horvath]

From: William Horvath

The key change is to never return STATUS_TIMEOUT, and to instead return the result of
NtYieldExecution() if zero timeout was passed, or STATUS_SUCCESS otherwise.

An overview of the correct values for each combination, copied from the test commit:
 - Non-alertable, zero timeout: STATUS_SUCCESS or STATUS_NO_YIELD_PERFORMED
 - Non-alertable, non-zero timeout: STATUS_SUCCESS
 - Alertable, zero timeout: STATUS_SUCCESS, STATUS_NO_YIELD_PERFORMED, or STATUS_USER_APC
 - Alertable, non-zero timeout: STATUS_SUCCESS or STATUS_USER_APC
 - Sleep/SleepEx don't modify LastError, no matter what
---
 dlls/ntdll/tests/sync.c |  1 -
 dlls/ntdll/unix/sync.c  | 18 ++++++++++++++----
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/dlls/ntdll/tests/sync.c b/dlls/ntdll/tests/sync.c
index d04b45d565a..b7c278f00ab 100644
--- a/dlls/ntdll/tests/sync.c
+++ b/dlls/ntdll/tests/sync.c
@@ -1088,7 +1088,6 @@ static void test_delayexecution(void)
         }
         else
         {
-            todo_wine_if(status == STATUS_TIMEOUT)
             ok( status == STATUS_SUCCESS || (!tests[i].timeout && status == STATUS_NO_YIELD_PERFORMED),
                 "got status %#lx.\n", status );
         }
diff --git a/dlls/ntdll/unix/sync.c b/dlls/ntdll/unix/sync.c
index 0ee16b360b3..2b01aaf83b8 100644
--- a/dlls/ntdll/unix/sync.c
+++ b/dlls/ntdll/unix/sync.c
@@ -1641,8 +1641,17 @@ NTSTATUS WINAPI NtYieldExecution(void)
  */
 NTSTATUS WINAPI NtDelayExecution( BOOLEAN alertable, const LARGE_INTEGER *timeout )
 {
+    unsigned int status = STATUS_SUCCESS;
+
     /* if alertable, we need to query the server */
-    if (alertable) return server_wait( NULL, 0, SELECT_INTERRUPTIBLE | SELECT_ALERTABLE, timeout );
+    if (alertable)
+    {
+        /* Since server_wait will result in an unconditional implicit yield,
+           we never return STATUS_NO_YIELD_PERFORMED */
+        if ((status = server_wait( NULL, 0, SELECT_INTERRUPTIBLE | SELECT_ALERTABLE, timeout )) == STATUS_TIMEOUT)
+            status = STATUS_SUCCESS;
+        return status;
+    }

if (!timeout || timeout->QuadPart == TIMEOUT_INFINITE)  /* sleep forever */
     {
@@ -1659,9 +1668,10 @@ NTSTATUS WINAPI NtDelayExecution( BOOLEAN alertable, const LARGE_INTEGER *timeou
             when = now.QuadPart - when;
         }

-        /* Note that we yield after establishing the desired timeout */
-        NtYieldExecution();
-        if (!when) return STATUS_SUCCESS;
+        /* Note that we yield after establishing the desired timeout, but
+           we only care about the result of the yield for zero timeouts */
+        status = NtYieldExecution();
+        if (!when) return status;

for (;;)
         {