# UEFI port

This directory contains everything needed to build radare2 as an EFI
application (`BOOTX64.EFI`) that runs on top of the UEFI firmware, with no
operating system and no libc underneath.

* The build uses the musl headers (`musl-dev`) plus the small compatibility
  wrappers in `dist/uefi/include`
* `dist/uefi/include/uefi.c` implements the required libc subset on top of the boot
  services: console io through the simple text protocols, the heap through
  `AllocatePool`, file io through the simple file system protocol of the
  boot volume, time through the runtime services, and plain C
  implementations for the str/mem/printf/qsort/math family
* Threads, QuickJS, fork, dynamic loading, sockets, CAN bus, ptrace, shared
  memory and the debugger are disabled
* `dist/uefi/main.c` is the `efi_main` entrypoint: it calls `r_uefi_init ()`
  to hand the boot services over to the shim and then spawns the usual r2
  core prompt loop
* `dist/uefi/relocate.c` replaces the gnu-efi `_relocate`, which relies on
  implicit addends that bfd ld writes but lld does not

## Dependencies

```bash
sudo apt install -y build-essential binutils clang lld gnu-efi musl-dev
```

## Building

```bash
make -C dist/uefi
```

That configures the ACR/make build, compiles the static libraries and links
`build-uefi/BOOTX64.EFI`. The steps can be run separately with
`make -C dist/uefi configure build link`.

## Running

```bash
sudo apt install -y qemu-system-x86 ovmf
make -C dist/uefi run
```

Which boots the application in qemu with the OVMF firmware:

```
radare2 6.2.1 on UEFI
[0x00000000]> ?V
6.2.1 ...
[0x00000000]> wx 9090
[0x00000000]> px 16
```

To run it on real hardware copy `BOOTX64.EFI` into `EFI/BOOT/` on a FAT32
formatted usb stick and select it from the firmware boot menu.