Re: [PATCH] UUID for FAT

[Robert Millan <rmh@aybabtu.com>]

Committed.

On Sat, May 31, 2008 at 11:05:35PM +0200, Robert Millan wrote:
> 
> This patch implements UUID support for FAT (both 12/16 and 32).
> 
> -- 
> Robert Millan
> 
> <GPLv2> I know my rights; I want my phone call!
> <DRM> What good is a phone call… if you are unable to speak?
> (as seen on /.)

> 2008-05-31  Robert Millan  <rmh@aybabtu.com>
> 
> 	* fs/fat.c (struct grub_fat_bpb): Move fat32-specific fields into a
> 	union with fat12/fat16-specific ones.  Add some new fields, including
> 	`num_serial' for both versions.
> 	(struct grub_fat_data): Add `uuid' member.
> 	(grub_fat_mount): Refer to fat32-specific fields in `bpb' by their new
> 	names.  Initialize `data->uuid' using `num_serial'.
> 	(grub_fat_uuid): New function.
> 	(grub_fat_fs): Reference grub_fat_uuid() in `uuid' struct member.
> 
> diff -x configure -x config.h.in -x CVS -x '*~' -x '*.mk' -urp ../grub2/fs/fat.c ./fs/fat.c
> --- ../grub2/fs/fat.c	2007-08-02 20:40:36.000000000 +0200
> +++ ./fs/fat.c	2008-05-31 22:59:11.000000000 +0200
> @@ -61,14 +61,34 @@ struct grub_fat_bpb
>    grub_uint16_t num_heads;
>    grub_uint32_t num_hidden_sectors;
>    grub_uint32_t num_total_sectors_32;
> -  
> -  /* The following fields are only used by FAT32.  */
> -  grub_uint32_t sectors_per_fat_32;
> -  grub_uint16_t extended_flags;
> -  grub_uint16_t fs_version;
> -  grub_uint32_t root_cluster;
> -  grub_uint16_t fs_info;
> -  grub_uint16_t backup_boot_sector;
> +  union
> +  {
> +    struct
> +    {
> +      grub_uint8_t num_ph_drive;
> +      grub_uint8_t reserved;
> +      grub_uint8_t boot_sig;
> +      grub_uint32_t num_serial;
> +      grub_uint8_t label[11];
> +      grub_uint8_t fstype[8];
> +    } __attribute__ ((packed)) fat12_or_fat16;
> +    struct
> +    {
> +      grub_uint32_t sectors_per_fat_32;
> +      grub_uint16_t extended_flags;
> +      grub_uint16_t fs_version;
> +      grub_uint32_t root_cluster;
> +      grub_uint16_t fs_info;
> +      grub_uint16_t backup_boot_sector;
> +      grub_uint8_t reserved[12];
> +      grub_uint8_t num_ph_drive;
> +      grub_uint8_t reserved1;
> +      grub_uint8_t boot_sig;
> +      grub_uint32_t num_serial;
> +      grub_uint8_t label[11];
> +      grub_uint8_t fstype[8];
> +    } __attribute__ ((packed)) fat32;
> +  } __attribute__ ((packed)) version_specific;
>  } __attribute__ ((packed));
>  
>  struct grub_fat_dir_entry
> @@ -122,6 +142,8 @@ struct grub_fat_data
>    grub_uint32_t file_cluster;
>    grub_uint32_t cur_cluster_num;
>    grub_uint32_t cur_cluster;
> +
> +  grub_uint16_t uuid[2];
>  };
>  
>  #ifndef GRUB_UTIL
> @@ -183,7 +205,7 @@ grub_fat_mount (grub_disk_t disk)
>  
>    data->sectors_per_fat = ((bpb.sectors_per_fat_16
>  			    ? grub_le_to_cpu16 (bpb.sectors_per_fat_16)
> -			    : grub_le_to_cpu32 (bpb.sectors_per_fat_32))
> +			    : grub_le_to_cpu32 (bpb.version_specific.fat32.sectors_per_fat_32))
>  			   << data->logical_sector_bits);
>    if (data->sectors_per_fat == 0)
>      goto fail;
> @@ -219,9 +241,9 @@ grub_fat_mount (grub_disk_t disk)
>    if (! bpb.sectors_per_fat_16)
>      {
>        /* FAT32.  */
> -      grub_uint16_t flags = grub_le_to_cpu16 (bpb.extended_flags);
> +      grub_uint16_t flags = grub_le_to_cpu16 (bpb.version_specific.fat32.extended_flags);
>        
> -      data->root_cluster = grub_le_to_cpu32 (bpb.root_cluster);
> +      data->root_cluster = grub_le_to_cpu32 (bpb.version_specific.fat32.root_cluster);
>        data->fat_size = 32;
>        data->cluster_eof_mark = 0x0ffffff8;
>        
> @@ -236,7 +258,7 @@ grub_fat_mount (grub_disk_t disk)
>  	  data->fat_sector += active_fat * data->sectors_per_fat;
>  	}
>  
> -      if (bpb.num_root_entries != 0 || bpb.fs_version != 0)
> +      if (bpb.num_root_entries != 0 || bpb.version_specific.fat32.fs_version != 0)
>  	goto fail;
>      }
>    else
> @@ -286,6 +308,12 @@ grub_fat_mount (grub_disk_t disk)
>        first_fat &= 0x00000fff;
>        magic = 0x0f00;
>      }
> +
> +  /* Serial number.  */
> +  if (bpb.sectors_per_fat_16)
> +    *((grub_uint32_t *) &data->uuid) = grub_le_to_cpu32 (bpb.version_specific.fat12_or_fat16.num_serial);
> +  else
> +    *((grub_uint32_t *) &data->uuid) = grub_le_to_cpu32 (bpb.version_specific.fat32.num_serial);
>    
>    /* Ignore the 3rd bit, because some BIOSes assigns 0xF0 to the media
>       descriptor, even if it is a so-called superfloppy (e.g. an USB key).
> @@ -797,6 +825,34 @@ grub_fat_label (grub_device_t device, ch
>    return grub_errno;
>  }
>  
> +static grub_err_t
> +grub_fat_uuid (grub_device_t device, char **uuid)
> +{
> +  struct grub_fat_data *data;
> +  grub_disk_t disk = device->disk;
> +
> +#ifndef GRUB_UTIL
> +  grub_dl_ref (my_mod);
> +#endif
> +
> +  data = grub_fat_mount (disk);
> +  if (data)
> +    {
> +      *uuid = grub_malloc (40 + sizeof ('\0'));
> +      grub_sprintf (*uuid, "%04x-%04x", data->uuid[1], data->uuid[0]);
> +    }
> +  else
> +    *uuid = NULL;
> +
> +#ifndef GRUB_UTIL
> +  grub_dl_unref (my_mod);
> +#endif
> +
> +  grub_free (data);
> +
> +  return grub_errno;
> +}
> +
>  static struct grub_fs grub_fat_fs =
>    {
>      .name = "fat",
> @@ -805,6 +861,7 @@ static struct grub_fs grub_fat_fs =
>      .read = grub_fat_read,
>      .close = grub_fat_close,
>      .label = grub_fat_label,
> +    .uuid = grub_fat_uuid,
>      .next = 0
>    };
>  

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-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What good is a phone call… if you are unable to speak?
(as seen on /.)