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util/main-loop: Avoid adding the same HANDLE twice

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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>
Message-Id: <20221019102015.2441622-2-bmeng.cn@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Bin Meng 2022-10-19 18:20:14 +08:00 committed by Paolo Bonzini
parent 4f76b3d9bb
commit d393b0a176
2 changed files with 12 additions and 0 deletions
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2
include/qemu/main-loop.h
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@ -157,6 +157,8 @@ typedef void WaitObjectFunc(void *opaque);
* in the main loop's calls to WaitForMultipleObjects. When the handle * in the main loop's calls to WaitForMultipleObjects. When the handle
* is in a signaled state, QEMU will call @func. * 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. * @handle: The Windows handle to be observed.
* @func: A function to be called when @handle is in a signaled state. * @func: A function to be called when @handle is in a signaled state.
* @opaque: A pointer-size value that is passed to @func. * @opaque: A pointer-size value that is passed to @func.

10
util/main-loop.c
View File

@ -373,10 +373,20 @@ static WaitObjects wait_objects = {0};
int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque) int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
{ {
int i;
WaitObjects *w = &wait_objects; WaitObjects *w = &wait_objects;
if (w->num >= MAXIMUM_WAIT_OBJECTS) { if (w->num >= MAXIMUM_WAIT_OBJECTS) {
return -1; 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->events[w->num] = handle;
w->func[w->num] = func; w->func[w->num] = func;
w->opaque[w->num] = opaque; w->opaque[w->num] = opaque;