# parse the embedded ELF (physical address from elf_phys()) and run it in ring 3

const PT_LOAD = 1
const PAGE_FLAGS = 6      # WRITE | USER

fn cmd_run() do
  const base = elf_phys()
  if mem_read(base, 4) != 0x464c457f do
    puts("run: not an ELF\n")
    return :nil
  end
  const entry = mem_read(base + 24, 8)
  const phoff = mem_read(base + 32, 8)
  const phnum = mem_read(base + 56, 2)
  const phentsize = mem_read(base + 54, 2)
  const as = as_create()
  for i in 0..phnum do
    const ph = base + phoff + i * phentsize
    if mem_read(ph, 4) == PT_LOAD do
      const offset = mem_read(ph + 8, 8)
      const vaddr = mem_read(ph + 16, 8)
      const filesz = mem_read(ph + 32, 8)
      const memsz = mem_read(ph + 40, 8)
      let off = 0
      while off < memsz do
        const frame = frame_alloc()
        mem_zero(frame, 4096)
        if off < filesz do
          const left = filesz - off
          mem_copy(frame, base + offset + off, if left > 4096 4096 else left)
        end
        as_map(as, vaddr + off, frame, PAGE_FLAGS)
        off = off + 4096
      end
    end
  end
  const stack_top = 0x7fff0000
  as_map(as, stack_top - 4096, frame_alloc(), PAGE_FLAGS)
  proc_run(as, entry, stack_top)
end