Re: [Qemu-devel] [PATCH v2 for-2.7] wxx: Fix handling of files used for character devices

[Peter Maydell]

On 2 August 2016 at 07:47, Paolo Bonzini <address@hidden> wrote:
>
>
> On 02/08/2016 07:14, Stefan Weil wrote:
>> On Windows, such files were not truncated like on all other hosts.
>> Now we also test whether truncation is needed when running on Windows.
>>
>> The append case was also incorrect because it needs a different value
>> for the desired access mode.
>>
>> Reported-by: Benjamin David Lunt <address@hidden>
>> Signed-off-by: Stefan Weil <address@hidden>
>> ---
>>
>> This patch supersedes my previous patch for qemu-char which only
>> fixed the truncate case. Paolo gave the hint to the wrong access mode
>> (see also commit 52074d0f662fc51293d4cde8077631f754784405).
>>
>> Regards
>> Stefan
>>
>>  qemu-char.c | 16 ++++++++++++++--
>>  1 file changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/qemu-char.c b/qemu-char.c
>> index e4b8448..e7d3399 100644
>> --- a/qemu-char.c
>> +++ b/qemu-char.c
>> @@ -4197,14 +4197,26 @@ static CharDriverState *qmp_chardev_open_file(const 
>> char *id,
>>      ChardevFile *file = backend->u.file.data;
>>      ChardevCommon *common = qapi_ChardevFile_base(file);
>>      HANDLE out;
>> +    DWORD accessmode;
>> +    DWORD flags;
>>
>>      if (file->has_in) {
>>          error_setg(errp, "input file not supported");
>>          return NULL;
>>      }
>>
>> -    out = CreateFile(file->out, GENERIC_WRITE, FILE_SHARE_READ, NULL,
>> -                     OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
>> +    if (file->has_append && file->append) {
>> +        /* Append to file if it already exists. */
>> +        accessmode = FILE_GENERIC_WRITE & ~FILE_WRITE_DATA;
>> +        flags = OPEN_ALWAYS;
>> +    } else {
>> +        /* Truncate file if it already exists. */
>> +        accessmode = GENERIC_WRITE;
>> +        flags = CREATE_ALWAYS;
>> +    }
>> +
>> +    out = CreateFile(file->out, accessmode, FILE_SHARE_READ, NULL, flags,
>> +                     FILE_ATTRIBUTE_NORMAL, NULL);
>>      if (out == INVALID_HANDLE_VALUE) {
>>          error_setg(errp, "open %s failed", file->out);
>>          return NULL;
>>
>
> Matches the access mode and flags for qemu-ga.
>
> Reviewed-by: Paolo Bonzini <address@hidden>

Applied to master, thanks.

-- PMM