RE: Read Sectors

[Julio Alberto Cruz Barroso]

OK, OK. 

I use the following function to read files with success:

---------------------------------------
static int 
smtt_send_file(char * pathname)
{
 static unsigned char Buffer[FILE_BUFFER_SIZE];
 grub_file_t file = 0;
 grub_off_t ofs, len;
 unsigned long long bytes_sent = 0;
 file = grub_file_open (pathname);
 
 if (!file)
    {
      grub_dprintf ("mcu","cannot open file %s", pathname);
      return -1;
    }


grub_dprintf ("mcu","file size : %lld \n", (unsigned long long) file->size);




ofs = 0;
len = file->size;

file->offset = 0;


while (len)
    {
      grub_ssize_t sz;
      sz = grub_file_read (file, Buffer, (len > FILE_BUFFER_SIZE) ? 
FILE_BUFFER_SIZE : len);
      if (sz < 0)
        {
          grub_dprintf ("mcu","read error at offset %llu: %s\n", ofs, 
grub_errmsg);
          break;
        }
#ifdef MCUDEBUG
     grub_getkey();
      grub_printf ("sending pack %llu \n", ofs);
#endif
      if(!smtt_send_package ( Buffer, sz))
        {
          bytes_sent +=sz;
          if ((sz == 0))
          break;
          ofs += sz;
          len -= sz;
        }
        else
        {
          grub_dprintf("mcu", "Error Sending Package\n");
          break;
        }
    }
//grub_printf ("file size : %lld \n", (unsigned long long) file->size);
//grub_printf ("Bytes Sends: %lld \n", bytes_sent);
grub_file_close (file);

return 0;
}
---------------------------------------------------------

Now, I need to read the OS partition sectors (not files). For example, from 
sector 1 to sector 500. 

I'm not sure which function to use to get this. For example, the functions 
"read" and "write" in a C/C++ Linux program.

Julio



-----Original Message-----
From: address@hidden [mailto:address@hidden On Behalf Of Vladimir 
'f-coder/phcoder' Serbinenko
Sent: Wednesday, October 12, 2011 9:49 PM
To: The development of GNU GRUB
Subject: Re: Read Sectors

On 12.10.2011 05:03, Julio Alberto Cruz Barroso wrote:
>
> Dear all,
>
>  
>
> I have a module to read some byte sectors from a OS partition to get a 
> HASH and validate the OS.
>
>  
>
> I try to use grub_file_open and grub_disk_open function without success.
>
And I'm telepath to know what exactly the code you're trying. And if you code 
for anything have a look around for the use of the function in question e.g. in 
ntldr.c
>
>  
>
> My system have two (2) compact flash (hard disk). The system must boot 
> with one CF or two CF (with priority setup).
>
>  
>
> Thanks all,
>
>  
>
> Julio
>
>
> _______________________________________________
> Grub-devel mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/grub-devel


--
Regards
Vladimir 'φ-coder/phcoder' Serbinenko