Read Sectors

Read Sectors

[Julio Alberto Cruz Barroso]

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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.

 

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


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RE: Read Sectors

[Julio Alberto Cruz Barroso]

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I already read some files from the OS partition but now we need to read
all data partition.

 

 

From: grub-devel-bounces+julio.cruz=smartmatic.com@gnu.org
[mailto:grub-devel-bounces+julio.cruz=smartmatic.com@gnu.org] On Behalf
Of Julio Alberto Cruz Barroso
Sent: Tuesday, October 11, 2011 10:33 PM
To: grub-devel@gnu.org
Subject: Read Sectors

 

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.

 

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


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Re: Read Sectors

[Vladimir 'φ-coder/phcoder' Serbinenko]

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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
> Grub-devel@gnu.org
> https://lists.gnu.org/mailman/listinfo/grub-devel


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



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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: grub-devel-bounces+julio.cruz=smartmatic.com@gnu.org [mailto:grub-devel-bounces+julio.cruz=smartmatic.com@gnu.org] 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
> Grub-devel@gnu.org
> https://lists.gnu.org/mailman/listinfo/grub-devel


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

RE: Read Sectors

[Julio Alberto Cruz Barroso]

I used this with success:

--------------
11.3 How to specify block lists

A block list is used for specifying a file that doesn't appear in the filesystem, like a chainloader. The syntax is [offset]+length[,[offset]+length].... Here is an example:

     0+100,200+1,300+300
This represents that GRUB should read blocks 0 through 99, block 200, and blocks 300 through 599. If you omit an offset, then GRUB assumes the offset is zero.

Like the file name syntax (see File name syntax), if a blocklist does not contain a device name, then GRUB uses GRUB's root device. So (hd0,2)+1 is the same as +1 when the root device is ‘(hd0,2)’.
---------------

Regards,

JC

-----Original Message-----
From: grub-devel-bounces+julio.cruz=smartmatic.com@gnu.org [mailto:grub-devel-bounces+julio.cruz=smartmatic.com@gnu.org] On Behalf Of Julio Alberto Cruz Barroso
Sent: Tuesday, October 25, 2011 9:09 AM
To: The development of GNU GRUB
Subject: RE: Read Sectors

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: grub-devel-bounces+julio.cruz=smartmatic.com@gnu.org [mailto:grub-devel-bounces+julio.cruz=smartmatic.com@gnu.org] 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
> Grub-devel@gnu.org
> https://lists.gnu.org/mailman/listinfo/grub-devel


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


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