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

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

[Fabien Chouteau]

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 <chouteau@adacore.com>
---
 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);
 
     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;
     }
-- 
1.7.5.1

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<chouteau@adacore.com>
> ---
>   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 <pbonzini@redhat.com>

Paolo

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

[Anthony Liguori]

On 11/07/2011 08:36 AM, 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<chouteau@adacore.com>

Applied.  Thanks.

Regards,

Anthony Liguori

> ---
>   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);
>
>       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;
>       }