[parted-devel] [PATCH v2] dos: improve MBR signature generation

[Jonathan Liu]

On 2/10/2013 12:43 AM, Jim Meyering wrote:
> On Thu, Sep 26, 2013 at 6:17 PM, Jonathan Liu <net147 at gmail.com> wrote:
>> Using tv_usec in struct timeval from gettimeofday() doesn't provide
>> enough precision to fill an unsigned 32-bit integer and isn't really
>> random. It it always less than one million when using the GNU C library
>> while an unsigned 32-bit integer ranges between 0 and 4294967295.
>>
>> A better random generator is used for FAT filesystem creation so move
>> it into a common function and use it for MS-DOS MBR signature
>> generation.
>>
>> * libparted/fs/r/fat/fat.c (_gen_new_serial_number): Remove.
>> (fat_create): Use generate_random_uint32 instead of
>> _gen_new_serial_number.
>> * libparted/labels/dos.c (generate_random_id): Remove.
>> (msdos_write): Use generate_random_uint32 instead of
>> generate_random_id.
>> * libparted/labels/misc.h (generate_random_uint32): New function.
>> Created from _gen_new_serial_number in libparted/fs/r/fat/fat.c with
>> additional check to avoid returning zero which may be interpreted
>> as no FAT serial number or no MBR signature.
> Thank you for the patch.  Normally we require copyright assignment,
> but this change is small enough to get by without that.  Would you
> please amend your commit to do two things:
>    - insert a note in NEWS that describes this change
>    - move or copy the commit-log comment about the meaning of that zero
> into the function's comment.
>
> With those, it should be good to push, assuming "make syntax-check"
> and "make check" still pass.
Done. Submitted as V3 patch.

Regards,
Jonathan