last_FL_duty query testing for Kobo Aura HD with kernel 2.6.35.3

koboflquery.lua

local ffi = require("ffi")
local C = ffi.C
ffi.cdef[[
static const int O_RDONLY = 0;
static const int SEEK_SET = 0;
int open(const char *, int, ...);
int close(int);
long int lseek(int, long int, int) __attribute__((__nothrow__, __leaf__));
int read(int, void *, unsigned int);
]]
function getLastFLDuty()
	local phys_start, value
	local var_addr = 0x803b8b58
	local page_offset = 0x80000000
	for line in io.lines("/proc/iomem") do
		phys_start = line:match("^(%x+)-%x+ : System RAM")
		if phys_start then
			phys_start = tonumber(phys_start, 16)
			break
		end
	end
	if var_addr and page_offset and phys_start then
		local data = ffi.new("int[1]")
		local fd = C.open("/dev/mem", C.O_RDONLY)
		C.lseek(fd, var_addr + phys_start - page_offset, C.SEEK_SET)
		if C.read(fd, data, ffi.sizeof(data)) ~= -1 then
			value = data[0]
		end
		C.close(fd)
	end
	return value
end
print(bit.tohex(getLastFLDuty()))