Re: [Qemu-devel] [PATCH 1.0] Replace WriteFileEx with WriteFile in qemu_create_pidfile

[Paolo Bonzini]

On 11/07/2011 03:36 PM, Fabien Chouteau wrote:
> The function that writes pidfile for win32 uses WriteFileEx which is an
> asynchronous IO function. The arguments given to WriteFileEx are allocated on
> the stack and one of them is "in out". When the IO operation is actually
> executed the calling function has already returned, so the arguments are no
> longer allocated or allocated to another frame.
>
> Signed-off-by: Fabien Chouteau<address@hidden>
> ---
>   os-win32.c |    7 ++++---
>   1 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/os-win32.c b/os-win32.c
> index 7909401..8ad5fa1 100644
> --- a/os-win32.c
> +++ b/os-win32.c
> @@ -130,14 +130,15 @@ int qemu_create_pidfile(const char *filename)
>       memset(&overlap, 0, sizeof(overlap));
>
>       file = CreateFile(filename, GENERIC_WRITE, FILE_SHARE_READ, NULL,
> -                     OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
> +                      OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);

This is s/tab/space/, unrelated but fine.

>       if (file == INVALID_HANDLE_VALUE) {
>           return -1;
>       }
>       len = snprintf(buffer, sizeof(buffer), "%d\n", getpid());
> -    ret = WriteFileEx(file, (LPCVOID)buffer, (DWORD)len,
> -               &overlap, NULL);
> +    ret = WriteFile(file, (LPCVOID)buffer, (DWORD)len,
> +                    NULL,&overlap);
> +    CloseHandle(file);
>       if (ret == 0) {
>           return -1;
>       }

Reviewed-by: Paolo Bonzini <address@hidden>

Paolo