How to read physical memory?

[bkowlagi]

I want to get read access to physical memory to search for certain bytes. The memory address range is 0x000F0000 to 0x000FFFFF that is 64K bytes. I tried using the following code

NTSTATUS status;
HANDLE physmem;

status = NtOpenSection( &physmem, SECTION_MAP_READ, &attributes );

if( !NT_SUCCESS( status )) {

PrintError( "Could not open \\device\\physicalmemory", status );
return NULL;
}

return physmem;

I am able to get the handle (physmem) but when I try

_lseek(physmem, 0L, SEEK_SET);

perror() gives "Bad file descriptor"

Is there an alternate way to read this section of memory?