little endian value returned from kernel thru a system call

[Karthik M <k_mohanas@yahoo.com>]

Hi everyone,

I am trying to implement the md5 check summing of a
message digest as a system call. I have everything
working except a little issue where the checksum
returned is in the little endian format.

I passed the string "abc" to be check summed by the
algorithm. The correct checksum for the string 'abc'
is:

"900150983cd24fb0d6963f7d28e17f72"

but the value that the system call returns is:

"ffffff900150ffffff983cffffffd24fffffffb0ffffffd6ffffff963f7d28ffffffe17f72"

which essentially contains the checksum embedded
inside. I looked through the source of 2.4.22 and 2.6
[test kernels] and saw that their implementation had a
le32_to_cpu_array and a vice versa function. I am not
sure what they do and how i should use them in my
program if i need to.

A little info about my program:

---------
char *message = "abc";
char checksum[16];

i =
md5checksum(message,(char*)checksum,strlen(message));
---------

The system call is a syscall3 type and it stores the
computed checksum in the variable checksum passed to
it.

Inside the system call:

---------
unsigned char md5sum[16];
....
....
md5_finish( &ctx, md5sum );
copy_to_user(checksum, md5sum,sizeof(md5sum));
---------

Any help to solve the problem would be of gr8 help to
me. I am trying to achieve this on a 2.4.21 kernel.

TIA

Karthik

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