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local version <const> = 1
---@enum Osabi
local Osabi <const> = {
sysv = 0x00,
hpux = 0x01,
netbsd = 0x02,
linux = 0x03,
hurd = 0x04,
solaris = 0x06,
aix = 0x07,
irix = 0x08,
freebsd = 0x09,
tru64 = 0x0a,
modesto = 0x0b,
openbsd = 0x0c,
openvms = 0x0d,
nsk = 0x0e,
aros = 0x0f,
fenixos = 0x10,
cloudabi = 0x11,
opevos = 0x12,
}
---@enum Class
local Class <const> = {
bit32 = 0x1,
bit64 = 0x2,
}
---@enum Endian
local Endian <const> = {
little = 0x1,
big = 0x2,
}
---@enum Type
local Type <const> = {
none = 0x00,
rel = 0x01,
exec = 0x02,
dyn = 0x03,
core = 0x04,
loos = 0xfe00,
hios = 0xfeff,
loproc = 0xfe00,
hiproc = 0xfeff,
}
---@enum Machine
local Machine <const> = {
none = 0x00,
att = 0x01,
sparc = 0x02,
x86 = 0x03,
m68k = 0x04,
m88k = 0x05,
-- todo
}
---@alias ElfMagic [integer, integer, integer, integer]
---@class ElfHeader
---@field magic ElfMagic
---@field class Class
---@field data Endian
---@field ident_version integer
---@field osabi Osabi
---@field abiversion integer
---@field type Type
---@field machine Machine
---@field version integer
---@field entry integer
---@field phoff integer
---@field shoff integer
---@field flags integer
---@field ehsize integer
---@field phentsize integer
---@field phnum integer
---@field shentsize integer
---@field shnum integer
---@field shstrndx integer
---@param hdr ElfHeader
---@nodiscard
local function ElfHeader_pack(hdr)
local ident = string.pack("BBBBBBBBBxxxxxxx",
hdr.magic[1], hdr.magic[2], hdr.magic[3], hdr.magic[4],
hdr.class,
hdr.data,
hdr.ident_version,
hdr.osabi,
hdr.abiversion)
local e = (hdr.data == Endian.big) and ">" or "<"
local sz = (hdr.class == Class.bit64) and "I8" or "I4"
local h = string.pack(e .. "I2I2I4" ..
sz .. sz .. sz ..
"I4I2I2I2I2I2I2",
hdr.type,
hdr.machine,
hdr.version,
hdr.entry,
hdr.phoff,
hdr.shoff,
hdr.flags,
hdr.ehsize,
hdr.phentsize,
hdr.phnum,
hdr.shentsize,
hdr.shnum,
hdr.shstrndx)
return ident .. h
end
---@type ElfHeader
local header <const> = {
magic = { 0x7f, 0x45, 0x4c, 0x46 },
class = Class.bit32,
data = Endian.big,
ident_version = version,
osabi = Osabi.netbsd,
abiversion = 0,
type = Type.exec,
machine = Machine.x86,
version = version,
entry = 0,
phoff = 0x34,
shoff = 0xff,
flags = 0,
ehsize = 52,
phentsize = 0x20,
phnum = 0,
shentsize = 0x28,
shnum = 0,
shstrndx = 0,
pack = ElfHeader_pack
}
local function main()
local output = "a.out"
for i in ipairs(arg) do
if arg[i] ~= "-o" then goto continue end
if not arg[i + 1] then
error("mkelf: missing filename after -o")
end
output = arg[i + 1]
::continue::
end
local f = assert(io.open(output, "w"))
f:write(header:pack())
f:close()
end
main()
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