build_mips.sh

#! /bin/sh
## Warning: Please don't source this script from within' another script(note the use of "exit")

red_color="\033[1;31m"
green_color="\033[1;32m"
no_color="\033[0m"

throw_error() {
  if [ ! -z "$1" ]; then
    printf "${red_color}$1${no_color}\n"
  fi

  printf "\n${red_color}Compilation failed!${no_color}\n"
  exit 1
}

## Commodity function to ensure that an error is thrown if a command fails to execute
## Usage: run (command) [error message if it fails]
run() {
  eval "$1" || throw_error "$2"
}

ensure_tool_is_avaiable() {
  if [ -z "$(which $1)" ]; then
    printf "Installing $1:\n"
    run \
    "sudo apt-get install $1 -y" \
    "\
    Failed to install $1: check that you have an internet connection or\n\
    that you have the rights to run 'sudo apt-get install $1'"
  fi
}

ensure_tools_are_available() {
  for tool in "$@"; do
    ensure_tool_is_avaiable "$1"
  done
}

## [error handling needed - "run" function] - did we have rights to remove the folder?
ensure_empty_folder() {
  if [ -d "$1" ]; then
    rm -rf "$1"
  fi

  mkdir -p "$1"
}

set_rust_build_folder() {
  rust_build_location="${1:-"$HOME/build-rust"}"

  ensure_empty_folder "${rust_build_location}"
}

## [error handling needed - "run" function] - did wget succeed? tar xf? rm -f?
get_and_extract_openwrt() {
  local openwrt_link
  local openwrt_archive

  openwrt_link="${1:-"http://downloads.openwrt.org/chaos_calmer/15.05/ar71xx/generic/OpenWrt-SDK-15.05-ar71xx-generic_gcc-4.8-linaro_uClibc-0.9.33.2.Linux-x86_64.tar.bz2"}"
  wget -c "${openwrt_link}"

  openwrt_archive="$(basename ${openwrt_link})"
  if [ -e "${openwrt_archive}" ]; then
    tar xf "${openwrt_archive}"
    rm -f "${openwrt_archive}"
    mv */ openwrt-sdk
  else
    throw_error
  fi
}

## [error handling needed - "run" function] - find worked? ls and ln -s?
setup_openwrt_toolchain() {
  local openwrt_compiler_path
  local openwrt_tools_path

  openwrt_compiler_path="$(readlink -m $(find . -name 'mips-openwrt-linux-gcc' | head -1))"
  openwrt_tools_path="$(dirname ${openwrt_compiler_path})"

  ## I don't take into consideration folder names with spaces but this should be ok for this purpose
  for tool in $(ls ${openwrt_tools_path}/*uclibc-*); do
    ln -sf "${tool}" "$(echo "${tool}" | sed "s/mips-openwrt-linux-uclibc/mips-linux-gnu/")"
  done

  export PATH="${openwrt_tools_path}:$PATH"
}

## [error handling needed - "run" function] - assuming git 1.7.3+, ...
prepare_rust_repository() {
  local rust_remote_git

  rust_remote_git="${1:-"https://github.com/rust-lang/rust.git"}"
  rust_local_git="${2:-"$HOME/Git/rust"}"

  if [ -d "${rust_local_git}" ]; then
    cd "${rust_local_git}"
    git pull --recurse-submodules
    git submodule update --recursive
  else
    local git_folder

    git_folder="$(dirname ${rust_local_git})"
    mkdir -p "${git_folder}"
    cd "${git_folder}"

    git clone --recursive "${rust_remote_git}" rust
  fi

  cd "${rust_local_git}"
  git reset --hard $(rustc -V | cut -d '(' -f 2 | cut -d ' ' -f 1)
}

prepare_final_installation_path() {
  final_rust_destination="${1:-"$HOME/rust-mips-openwrt-linux"}"
  ensure_empty_folder "${final_rust_destination}"
}

build_rust() {
  cd "${rust_build_location}"
  ensure_empty_folder "${rust_build_location}/build"

  ln -s "${rust_local_git}" rust
  cd build

  ../rust/configure --build=x86_64-unknown-linux-gnu --host=x86_64-unknown-linux-gnu --target=mips-unknown-linux-gnu --prefix="${final_rust_destination}"

  local number_of_jobs
  number_of_jobs="$(( $(nproc) + 1 ))"
  make -j ${number_of_jobs}
  make -j ${number_of_jobs} install
}

main() {
  ## Because we will need sudo rights later
  sudo -v

  ensure_tools_are_available git wget gcc build-essential

  set_rust_build_folder
  cd "${rust_build_location}"

  get_and_extract_openwrt
  setup_openwrt_toolchain

  prepare_rust_repository

  prepare_final_installation_path

  build_rust
}

main