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[PATCH v3 2/3] util/main-loop: Avoid adding the same HANDLE twice
From: |
Bin Meng |
Subject: |
[PATCH v3 2/3] util/main-loop: Avoid adding the same HANDLE twice |
Date: |
Wed, 24 Aug 2022 16:52:30 +0800 |
From: Bin Meng <bin.meng@windriver.com>
Fix the logic in qemu_add_wait_object() to avoid adding the same
HANDLE twice, as the behavior is undefined when passing an array
that contains same HANDLEs to WaitForMultipleObjects() API.
Signed-off-by: Bin Meng <bin.meng@windriver.com>
---
Changes in v3:
- new patch: avoid adding the same HANDLE twice
include/qemu/main-loop.h | 2 ++
util/main-loop.c | 10 ++++++++++
2 files changed, 12 insertions(+)
diff --git a/include/qemu/main-loop.h b/include/qemu/main-loop.h
index c50d1b7e3a..db8d380550 100644
--- a/include/qemu/main-loop.h
+++ b/include/qemu/main-loop.h
@@ -157,6 +157,8 @@ typedef void WaitObjectFunc(void *opaque);
* in the main loop's calls to WaitForMultipleObjects. When the handle
* is in a signaled state, QEMU will call @func.
*
+ * If the same HANDLE is added twice, this function returns -1.
+ *
* @handle: The Windows handle to be observed.
* @func: A function to be called when @handle is in a signaled state.
* @opaque: A pointer-size value that is passed to @func.
diff --git a/util/main-loop.c b/util/main-loop.c
index cb018dc33c..dae33a8daf 100644
--- a/util/main-loop.c
+++ b/util/main-loop.c
@@ -373,10 +373,20 @@ static WaitObjects wait_objects = {0};
int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
{
+ int i;
WaitObjects *w = &wait_objects;
+
if (w->num >= MAXIMUM_WAIT_OBJECTS) {
return -1;
}
+
+ for (i = 0; i < w->num; i++) {
+ /* check if the same handle is added twice */
+ if (w->events[i] == handle) {
+ return -1;
+ }
+ }
+
w->events[w->num] = handle;
w->func[w->num] = func;
w->opaque[w->num] = opaque;
--
2.34.1