Re: [Qemu-devel] [PATCH 1/3] qga: vss-win32: Use NULL as an invalid pointer for OpenEvent and CreateEvent

[Yan Vugenfirer]

On Jan 13, 2014, at 7:25 PM, Tomoki Sekiyama <address@hidden> wrote:

> OpenEvent and CreateEvent WinAPI return NULL when failed to open/create
> events handles, instead of INVALID_HANDLE_VALUE (although their return
> types are HANDLE).
> This replaces INVALID_HANDLE_VALUE related to event handles with NULL.
> 
> Signed-off-by: Tomoki Sekiyama <address@hidden>
> ---
> qga/vss-win32/provider.cpp  |    6 +++---
> qga/vss-win32/requester.cpp |   24 ++++++++++--------------
> 2 files changed, 13 insertions(+), 17 deletions(-)
> 
> diff --git a/qga/vss-win32/provider.cpp b/qga/vss-win32/provider.cpp
> index bf42b5e..c3030d8 100644
> --- a/qga/vss-win32/provider.cpp
> +++ b/qga/vss-win32/provider.cpp
> @@ -342,18 +342,18 @@ STDMETHODIMP CQGAVssProvider::CommitSnapshots(VSS_ID 
> SnapshotSetId)
>     HANDLE hEventFrozen, hEventThaw, hEventTimeout;
> 
>     hEventFrozen = OpenEvent(EVENT_ALL_ACCESS, FALSE, EVENT_NAME_FROZEN);
> -    if (hEventFrozen == INVALID_HANDLE_VALUE) {
> +    if (!hEventFrozen) {
>         return E_FAIL;
>     }
> 
>     hEventThaw = OpenEvent(EVENT_ALL_ACCESS, FALSE, EVENT_NAME_THAW);
> -    if (hEventThaw == INVALID_HANDLE_VALUE) {
> +    if (!hEventThaw) {
>         CloseHandle(hEventFrozen);
>         return E_FAIL;
>     }
> 
>     hEventTimeout = OpenEvent(EVENT_ALL_ACCESS, FALSE, EVENT_NAME_TIMEOUT);
> -    if (hEventTimeout == INVALID_HANDLE_VALUE) {
> +    if (!hEventTimeout) {
>         CloseHandle(hEventFrozen);
>         CloseHandle(hEventThaw);
>         return E_FAIL;
> diff --git a/qga/vss-win32/requester.cpp b/qga/vss-win32/requester.cpp
> index 1e8dd3d..0a55447 100644
> --- a/qga/vss-win32/requester.cpp
> +++ b/qga/vss-win32/requester.cpp
> @@ -50,10 +50,6 @@ static struct QGAVSSContext {
> 
> STDAPI requester_init(void)
> {
> -    vss_ctx.hEventFrozen =  INVALID_HANDLE_VALUE;
> -    vss_ctx.hEventThaw = INVALID_HANDLE_VALUE;
> -    vss_ctx.hEventTimeout = INVALID_HANDLE_VALUE;
> -
>     COMInitializer initializer; /* to call CoInitializeSecurity */
>     HRESULT hr = CoInitializeSecurity(
>         NULL, -1, NULL, NULL, RPC_C_AUTHN_LEVEL_PKT_PRIVACY,
> @@ -94,17 +90,17 @@ STDAPI requester_init(void)
> 
> static void requester_cleanup(void)
> {
> -    if (vss_ctx.hEventFrozen != INVALID_HANDLE_VALUE) {
> +    if (vss_ctx.hEventFrozen) {
>         CloseHandle(vss_ctx.hEventFrozen);
> -        vss_ctx.hEventFrozen = INVALID_HANDLE_VALUE;
> +        vss_ctx.hEventFrozen = NULL;
>     }
> -    if (vss_ctx.hEventThaw != INVALID_HANDLE_VALUE) {
> +    if (vss_ctx.hEventThaw) {
>         CloseHandle(vss_ctx.hEventThaw);
> -        vss_ctx.hEventThaw = INVALID_HANDLE_VALUE;
> +        vss_ctx.hEventThaw = NULL;
>     }
> -    if (vss_ctx.hEventTimeout != INVALID_HANDLE_VALUE) {
> +    if (vss_ctx.hEventTimeout) {
>         CloseHandle(vss_ctx.hEventTimeout);
> -        vss_ctx.hEventTimeout = INVALID_HANDLE_VALUE;
> +        vss_ctx.hEventTimeout = NULL;
>     }
>     if (vss_ctx.pAsyncSnapshot) {
>         vss_ctx.pAsyncSnapshot->Release();
> @@ -374,19 +370,19 @@ void requester_freeze(int *num_vols, ErrorSet *errset)
>     sa.bInheritHandle = FALSE;
> 
>     vss_ctx.hEventFrozen = CreateEvent(&sa, TRUE, FALSE, EVENT_NAME_FROZEN);
> -    if (vss_ctx.hEventFrozen == INVALID_HANDLE_VALUE) {
> +    if (!vss_ctx.hEventFrozen) {
>         err_set(errset, GetLastError(), "failed to create event %s",
>                 EVENT_NAME_FROZEN);
>         goto out;
>     }
>     vss_ctx.hEventThaw = CreateEvent(&sa, TRUE, FALSE, EVENT_NAME_THAW);
> -    if (vss_ctx.hEventThaw == INVALID_HANDLE_VALUE) {
> +    if (!vss_ctx.hEventThaw) {
>         err_set(errset, GetLastError(), "failed to create event %s",
>                 EVENT_NAME_THAW);
>         goto out;
>     }
>     vss_ctx.hEventTimeout = CreateEvent(&sa, TRUE, FALSE, EVENT_NAME_TIMEOUT);
> -    if (vss_ctx.hEventTimeout == INVALID_HANDLE_VALUE) {
> +    if (!vss_ctx.hEventTimeout) {
>         err_set(errset, GetLastError(), "failed to create event %s",
>                 EVENT_NAME_TIMEOUT);
>         goto out;
> @@ -443,7 +439,7 @@ void requester_thaw(int *num_vols, ErrorSet *errset)
> {
>     COMPointer<IVssAsync> pAsync;
> 
> -    if (vss_ctx.hEventThaw == INVALID_HANDLE_VALUE) {
> +    if (!vss_ctx.hEventThaw) {
>         /*
>          * In this case, DoSnapshotSet is aborted or not started,
>          * and no volumes must be frozen. We return without an error.
> 
> 

Reviewed-by: Yan Vugenfirer <address@hidden>