Re: [PATCH 2/5] filetype: add GPT support

[Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>]

On 18:32 Fri 15 Feb     , Sascha Hauer wrote:
> On Fri, Feb 15, 2013 at 02:35:14PM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:
> > GPT need to be check before MBR
> > 
> > Cc: Rob Herring <rob.herring@calxeda.com>
> > Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
> > ---
> >  common/filetype.c  |   47 +++++++++++++++++++++++++++++++++++++++++++++++
> >  include/filetype.h |    1 +
> >  2 files changed, 48 insertions(+)
> > 
> > diff --git a/common/filetype.c b/common/filetype.c
> > index 22fc621..06fa803 100644
> > --- a/common/filetype.c
> > +++ b/common/filetype.c
> > @@ -48,6 +48,7 @@ static const struct filetype_str filetype_str[] = {
> >  	[filetype_bmp] = { "BMP image", "bmp" },
> >  	[filetype_png] = { "PNG image", "png" },
> >  	[filetype_ext] = { "ext filesystem", "ext" },
> > +	[filetype_gpt] = { "GUID Partition Table", "gpt" },
> >  };
> >  
> >  const char *file_type_to_string(enum filetype f)
> > @@ -69,9 +70,52 @@ const char *file_type_to_short_string(enum filetype f)
> >  #define MBR_StartSector		8	/* MBR: Offset of Starting Sector in Partition Table Entry */
> >  #define BS_55AA			510	/* Boot sector signature (2) */
> >  #define MBR_Table		446	/* MBR: Partition table offset (2) */
> > +#define MBR_partition_size	16	/* MBR: Partition table offset (2) */
> >  #define BS_FilSysType32		82	/* File system type (1) */
> >  #define BS_FilSysType		54	/* File system type (1) */
> >  
> > +#define MBR_PART_sys_ind	4
> > +#define MBR_PART_start_sect	8
> > +#define MBR_OSTYPE_EFI_GPT	0xee
> > +
> > +static inline int pmbr_part_valid(const uint8_t *buf)
> > +{
> > +	if (buf[MBR_PART_sys_ind] == MBR_OSTYPE_EFI_GPT &&
> > +		get_unaligned_le32(&buf[MBR_PART_start_sect]) == 1UL) {
> > +		return 1;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +/**
> > + * is_gpt_valid(): test Protective MBR for validity and EFI PART
> > + * @mbr: pointer to a legacy mbr structure
> > + *
> > + * Description: Returns 1 if PMBR is valid, 0 otherwise.
> > + * Validity depends on two things:
> > + *  1) MSDOS signature is in the last two bytes of the MBR
> > + *  2) One partition of type 0xEE is found
> 
> Still wrong. This describes is_pmbr_valid, but the function is named and
> implements is_gpt_valid. I suggest implemting a real is_pmbr_valid
> function and call it from is_gpt_valid which additionally checks for the
> gpt header.

we test both pmr and EFI PART fo this is right

test Protective MBR for validity and EFI PART

so the comment is correct

Best Regards,
J.

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