#!/bin/bash
# Copyright 2019 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

### start fuchsia in aemu

## usage: fx aemu [-k] [-l] [-N] [-u <path>] [-e <directory>]
##   -k use KVM
##   -l run headless
##   -N run with emulated nic via tun/tap
##   -u <path> execute aemu if-up script, default is no script
##   -e <directory> location of emulator, defaults to looking in zircon/prebuilt/downloads/aemu
##   --audio run with audio hardware added to the virtual machine

set -e

source "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/lib/image_build_vars.sh || exit $?
source "${FUCHSIA_DIR}/buildtools/vars.sh"

KVM=0
NET=0
AUDIO=0
HEADLESS=""
AEMU_DIR=""
UPSCRIPT=no

while [[ $# -ge 1 ]]; do
  case "$1" in
  -h|--help)
    fx-command-help
    exit 0
    ;;
  -k)
    KVM=1
    ;;
  -l)
    HEADLESS="-headless"
    ;;
  -N)
    NET=1
    ;;
  -u)
    shift
    UPSCRIPT="$1"
    ;;
  -e)
    shift
    AEMU_DIR="$1"
    ;;
  --audio)
    AUDIO=1
    ;;
  *)
    break
  esac
  shift
done

# aemu is limited to x64 for now
if [[ "$FUCHSIA_ARCH" != "x64" ]]; then
  fx-error Unsupported arch
  exit 1
fi

if [[ -z "$AEMU_DIR" && -d "${FUCHSIA_DIR}/zircon/prebuilt/downloads/aemu" ]]; then
  AEMU_DIR="${FUCHSIA_DIR}/zircon/prebuilt/downloads/aemu/"
fi

# construct the args for aemu
ARGS=()
ARGS+=("-m" "2048")
ARGS+=("-serial" "stdio")
ARGS+=("-smp" "4,threads=2")
ARGS+=("-vga" "none")
ARGS+=("-machine" "q35")
ARGS+=("-device" "isa-debug-exit,iobase=0xf4,iosize=0x04")
ARGS+=("-device" "virtio-keyboard-pci")
ARGS+=("-device" "virtio_input_multi_touch_pci_1")

if (( $AUDIO )); then
  ARGS+=("-soundhw" "hda")
fi

if (( $KVM )); then
  ARGS+=("-enable-kvm" "-cpu" "host,migratable=no,+invtsc")
else
  ARGS+=("-cpu" "Haswell,+smap,-check,-fsgsbase")
fi

if (( $NET )); then
  IFNAME=""
  if [[ "$(uname -s)" == "Darwin" ]]; then
    IFNAME="tap0"
    if [[ ! -c "/dev/$IFNAME" ]]; then
      echo "To use aemu with networking on macOS, install the tun/tap driver:"
      echo "http://tuntaposx.sourceforge.net/download.xhtml"
      exit 1
    fi
    if [[ ! -w "/dev/$IFNAME" ]]; then
      echo "For networking /dev/$IFNAME must be owned by $USER. Please run:"
      echo "  sudo chown $USER /dev/$IFNAME"
      exit 1
    fi
  else
    IFNAME="qemu"
    TAP_IFS=$(ip tuntap show 2>/dev/null)
    if [[ ! "$TAP_IFS" =~ "${IFNAME}:" ]]; then
      echo "To use aemu with networking on Linux, configure tun/tap:"
      echo
      echo "sudo ip tuntap add dev $IFNAME mode tap user $USER && \\"
      echo "sudo ip link set $IFNAME up"
      exit 1
    fi
  fi
  ARGS+=("-netdev" "type=tap,ifname=$IFNAME,script=$UPSCRIPT,downscript=no,id=net0")
  HASH=$(echo $IFNAME | shasum)
  SUFFIX=$(for i in {0..2}; do echo -n :${HASH:$(( 2 * $i )):2}; done)
  MAC=",mac=52:54:00$SUFFIX"
  ARGS+=("-device" "e1000,netdev=net0${MAC}")
else
  ARGS+=("-net" "none")
fi

# Construction of a qcow image prevents aemu from writing back to the
# build-produced image file, which could cause timestamp issues with that file.
# Construction of the new ZBI adds //.ssh/authorized_keys for SSH access.
img_dir="$(mktemp -d)"
if [[ ! -d "${img_dir}" ]]; then
  fx-error "Failed to create temporary directory"
  exit 1
fi
trap 'rm -rf "$img_dir"' EXIT

# TODO: move image creation logic into a lib file that both `run` and `aeemu` will use.
KERNEL="${FUCHSIA_BUILD_DIR}/${IMAGE_QEMU_KERNEL_RAW}"
kernelzbi="${img_dir}/fuchsia-ssh.zbi"
"${ZIRCON_TOOLS_DIR}/zbi" -o "${kernelzbi}" "${FUCHSIA_BUILD_DIR}/${IMAGE_ZIRCONA_ZBI}" \
  --entry "data/ssh/authorized_keys=${FUCHSIA_DIR}/.ssh/authorized_keys"

if [ -n "$IMAGE_FVM_RAW" ]; then
  fvmimg="${img_dir}/fvm.blk"
  ARGS+=("-drive" "file=${fvmimg},format=raw,if=none,id=mydisk")
  ARGS+=("-device" "ich9-ahci,id=ahci" "-device" "ide-drive,drive=mydisk,bus=ahci.0")
  stat_flags=()
  if [[ $(uname) == "Darwin" ]]; then
    stat_flags+=("-x")
  fi
  stat_output=$(stat "${stat_flags[@]}" "${FUCHSIA_BUILD_DIR}/${IMAGE_FVM_RAW}")
  if [[ "$stat_output" =~ Size:\ ([0-9]+) ]]; then
    size="${BASH_REMATCH[1]}"
    newsize=$(($size * 2))
    # We must take a copy of the build artifact, rather than re-use it, as we
    # need to modify it in order to extend it.
    echo -n "Creating disk image..."
    cp "${FUCHSIA_BUILD_DIR}/${IMAGE_FVM_RAW}" "${fvmimg}"
    "${ZIRCON_TOOLS_DIR}/fvm" "${fvmimg}" extend --length "${newsize}"
    echo "done"
  else
    fx-error "Could not extend fvm, unable to stat fvm image"
  fi
fi

# construct the kernel cmd line for aemu
CMDLINE="kernel.serial=legacy "
# Propagate our TERM environment variable as a kernel command line
# argument.  This is first so that an explicit -c TERM=foo argument
# goes into CMDLINE later and overrides this.
if [[ -n $TERM ]]; then
    CMDLINE+="TERM=$TERM "
fi

# Add entropy to the kernel
CMDLINE+="kernel.entropy-mixin=$(head -c 32 /dev/urandom | shasum -a 256 | awk '{ print $1 }') "

# Don't 'reboot' the emulator if the kernel crashes
CMDLINE+="kernel.halt-on-panic=true "

# run aemu
set -x
exec "${AEMU_DIR}"emulator"$HEADLESS" -fuchsia -kernel "$KERNEL" -initrd "$kernelzbi" "${ARGS[@]}" \
     -append "$CMDLINE" "$@"