#!/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.

#### CATEGORY=Run, inspect and debug
### start fuchsia in an emulator

## usage: fx emu [-a <mode>] [-c <text>] [-N [-I <ifname>]] [-u <path>] [-v <build_variant>] [-g <port> [-r <fps>] [-t <cmd>]] [-x <port> [-X <directory>]] [-e <directory>] [-w <size>] [-s <cpus>] [-m <mb>] [-k <authorized_keys_file>] [-K <kernel_image>] [-z <zbi_image>] [-f <fvm_image>] [-p mouse|touch] [-H|--headless] [--audio] [--hidpi-scaling] [--software-gpu] [--debugger]
##   -a <mode> acceleration mode (auto, off, kvm, hvf, hax), default is auto
##   -c <text> append item to kernel command line
##   -ds <size> extends the fvm image size to <size> bytes. Default is twice the original size
##   -N run with emulated nic via tun/tap
##   -I <ifname> uses the tun/tap interface named ifname
##   -u <path> execute emu if-up script, default: linux: no script, macos: tap ifup script.
##   -v <build_variant> uses the build system variant to modify the total memory.
##   -e <directory> location of emulator, defaults to looking in prebuilt/third_party/android/aemu/release/PLATFORM
##   -g <port> enable gRPC service on port to control the emulator, default is 5556 when WebRTC service is enabled
##   -r <fps> webrtc frame rate when using gRPC service, default is 30
##   -t <cmd> execute the given command to obtain turn configuration
##   -x <port> enable WebRTC HTTP service on port
##   -X <directory> location of grpcwebproxy, defaults to looking in prebuilt/third_party/grpcwebproxy
##   -w <size> window size, default is 1280x800
##   -s <cpus> number of cpus, 1 for uniprocessor
##   -m <mb> total memory, in MB
##   -k <authorized_keys_file> SSH authorized keys file, otherwise defaults to ~/.ssh/fuchsia_authorized_keys
##   -K <kernel_image> path to image to use as kernel, defaults to kernel generated by the current build.
##   -z <zbi_image> path to image to use as ZBI, defaults to zircon-a generated by the current build.
##   -Z <zbi tool> path to a version of the `zbi` tool to use; defaults to the one in the current build directory.
##   -f <fvm_image> path to full FVM image, defaults to image generated by the current build.
##   -F <fvm tool> path to a version of the `fvm` tool to use; defaults to the one in the current build directory.
##   -A <arch> architecture of images (x64, arm64), default is the current build.
##   -p mouse|touch set pointing device used on emulator: mouse or multitouch screen; defaults to mouse.
##   -H|--headless run in headless mode
##   --audio run with audio hardware added to the virtual machine
##   --hidpi-scaling enable pixel scaling on HiDPI devices
##   --host-gpu run with host GPU acceleration
##   --software-gpu run without host GPU acceleration
##   --debugger pause on launch and wait for a debugger process to attach before resuming
##   --no-build do not attempt to build the fvm and zbi tools and the zbi image

set -e

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

echo
fx-info "The Fuchsia emulator is improving and will soon be launched in ffx. Want to be an early adopter?"
fx-info "Please use 'ffx emu' and send us feedback!"
echo
sleep 0.3

# Note these match the defaults in `fx qemu` (//zircon/scripts/run-zircon) and the ram value in
# `fx vdl` (//src/developer/ffx/plugins/emulator/src/vdl_files.rs). This can be overriden by the
# emulator configs in the infra/recipe repo
# (https://fuchsia.googlesource.com/infra/recipes/+/refs/heads/main/recipe_modules/emu/api.py).
readonly MEMSIZE_DEFAULT=8192
readonly SMP_DEFAULT=4

ACCEL="auto"
BUILD_VARIANT=
NET=0
DEBUGGER=0
IFNAME=""
AUDIO=0
HEADLESS=0
HIDPI_SCALING=0
AEMU="emulator"
AEMU_DIR=""
UPSCRIPT=
DOWNSCRIPT=no
WINDOW_SIZE="1280x800"
GRPC=
RTCFPS="30"
TURNCFG=""
GPU="auto"
VULKAN=1
HTTP=0
GRPCWEBPROXY_DIR=""
CMDLINE=""
OPT_CMDLINE=""
SMP=$SMP_DEFAULT
MEMSIZE=$MEMSIZE_DEFAULT
IMAGE_SIZE=
EXPERIMENT_ARM64=false
ARCH="${FUCHSIA_ARCH}"
KERNEL_IMAGE=""
FVM_IMAGE=""
ZBI_IMAGE=""
ZBI_TOOL=""
FVM_TOOL=""
POINTING_DEVICE="mouse"
BUILD=1
EMU_ARGS=()
HAS_MEMSIZE=false

# 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

while [[ $# -ge 1 ]]; do
  case "$1" in
  -h|--help)
    fx-command-help
    exit 0
    ;;
  -a)
    shift
    ACCEL="$1"
    ;;
  -c)
    shift
    OPT_CMDLINE+="$1 "
    ;;
  -ds)
    shift
    IMAGE_SIZE="$1"
    ;;
  -N)
    NET=1
    ;;
  -I)
    shift
    IFNAME="$1"
    ;;
  -u)
    shift
    UPSCRIPT="$1"
    ;;
  -v)
    shift
    BUILD_VARIANT="$1"
    ;;
  -e)
    shift
    AEMU_DIR="$1"
    ;;
  -x)
    shift
    HTTP="$1"
    ;;
  -X)
    shift
    GRPCWEBPROXY_DIR="$1"
    ;;
  -g)
    shift
    GRPC="$1"
    ;;
  -r)
    shift
    RTCFPS="$1"
    ;;
  -t)
    shift
    TURNCFG="$1"
    ;;
  -w)
    shift
    WINDOW_SIZE="$1"
    ;;
  -s)
    shift
    SMP="$1"
    ;;
  -m)
    shift
    MEMSIZE="$1"
    HAS_MEMSIZE=true
    ;;
  -k)
    shift
    AUTHORIZED_KEYS="$1"
    ;;
  -K)
    shift
    KERNEL_IMAGE="$1"
    ;;
  -z)
    shift
    ZBI_IMAGE="$1"
    ;;
  -Z)
    shift
    ZBI_TOOL="$1"
    ;;
  -f)
    shift
    FVM_IMAGE="$1"
    ;;
  -F)
    shift
    FVM_TOOL="$1"
    ;;
  -A)
    shift
    ARCH="$1"
    ;;
  -p)
    shift
    POINTING_DEVICE="$1"
    ;;
  -H|--headless)
    HEADLESS=1
    ;;
  --audio)
    AUDIO=1
    ;;
  --debugger)
    DEBUGGER=1
    ;;
  --hidpi-scaling)
    HIDPI_SCALING=1
    ;;
  --host-gpu)
    GPU="host"
    ;;
  --software-gpu)
    GPU="swiftshader_indirect"
    ;;
  --no-build)
    BUILD=0
    ;;
  --experiment-arm64)
    EXPERIMENT_ARM64=true
    ;;
  *)
    EMU_ARGS+=("$1")
    ;;
  esac
  shift
done

build_targets=()
if [[ -z "${KERNEL_IMAGE}" ]] ; then
  KERNEL_IMAGE="$(fx-command-run list-build-artifacts --type kernel --name qemu-kernel images)"
  build_targets+=( "${KERNEL_IMAGE}" )
  KERNEL_IMAGE="${FUCHSIA_BUILD_DIR}/${KERNEL_IMAGE}"
fi

if [[ -z "${ZBI_IMAGE}" ]] ; then
  ZBI_IMAGE="$(fx-command-run list-build-artifacts --type zbi --name zircon-a images)"
  build_targets+=( "${ZBI_IMAGE}" )
  ZBI_IMAGE="${FUCHSIA_BUILD_DIR}/${ZBI_IMAGE}"
fi

if [[ -z "${FVM_IMAGE}" ]] ; then
  # Not all builds use an FVM so failing to find a source FVM is OK.
  FVM_IMAGE="$(fx-fvm-find-raw-source)"
  if [[ -n "${FVM_IMAGE}" ]]; then
    build_targets+=( "${FVM_IMAGE}" )
    FVM_IMAGE="${FUCHSIA_BUILD_DIR}/${FVM_IMAGE}"
  fi
fi

if (( BUILD )) && [[ ${#build_targets[@]} -gt 0 ]]; then
  _targets="$(printf ", %s" "${build_targets[@]}")"
  fx-info "Building ${_targets:2}"
  fx-command-run build "${build_targets[@]}"
fi

if [[ -z "${ZBI_TOOL}" ]] ; then
  (( BUILD )) && build_flag="" || build_flag="--no-build"
  ZBI_TOOL="$(fx-command-run host-tool ${build_flag} --print zbi)"
fi

if [[ -z "${FVM_TOOL}" ]] ; then
  (( BUILD )) && build_flag="" || build_flag="--no-build"
  FVM_TOOL="$(fx-command-run host-tool ${build_flag} --print fvm)"
fi

# TODO(fxbug.dev/62631): femu.sh relies on "-a auto", which makes use of
# HOST_CPU, which is an fx internal variable. In that case, fall back to
# defining it so that things work as expected.
if [[ -z "${HOST_CPU}" ]]; then
  case "$(uname -m)" in
    x86_64)
      readonly HOST_CPU="x64"
      ;;
    aarch64)
      readonly HOST_CPU="arm64"
      ;;
    *)
      echo >&2 "Unknown architecture: $(uname -m)."
      exit 1
      ;;
  esac
fi

if [[ "$ARCH" != "$HOST_CPU" ]]; then
  ACCEL=off
fi

if [[ -z "$AEMU_DIR" && -d "$PREBUILT_AEMU_DIR" ]]; then
  AEMU_DIR="$PREBUILT_AEMU_DIR"
fi

if [[ -z "$GRPCWEBPROXY_DIR" && -d "$PREBUILT_GRPCWEBPROXY_DIR" ]]; then
  GRPCWEBPROXY_DIR="$PREBUILT_GRPCWEBPROXY_DIR"
fi

if [[ -z "$AUTHORIZED_KEYS" ]]; then
  AUTHORIZED_KEYS="$(get-ssh-authkeys)"
fi

# if memory size is not specified, assign memory size based on build_variant.
if [[ ! ("$HAS_MEMSIZE" && -z "$BUILD_VARIANT") ]]; then
  variants=("asan" "asan-ubsan" "coverage" "coverage-rust" "profile")
  if [[ ! ${variants[*]} =~ "$BUILD_VARIANT " ]]; then
    MEMSIZE=4096
  fi
fi

# construct the args for aemu
ARGS=()
ARGS+=("-m" "$MEMSIZE")
ARGS+=("-serial" "stdio")
ARGS+=("-vga" "none")
ARGS+=("-device" "virtio-keyboard-pci")

if [[ $SMP != 1 ]]; then
  ARGS+=("-smp" "${SMP}")
fi

# TODO(raggi): do we want to use hda on arm64?
if (( AUDIO )); then
  ARGS+=("-soundhw" "hda")
fi

FEATURES="VirtioInput,GLDirectMem,HostComposition"

if [[ "$POINTING_DEVICE" == "mouse" ]]; then
  ARGS+=("-device" "virtio-mouse-pci")
  FEATURES+=",VirtioMouse"
elif [[ "$POINTING_DEVICE" == "touch" ]]; then
  ARGS+=("-device" "virtio_input_multi_touch_pci_1")
else
  fx-error "Unsupported pointing device: $POINTING_DEVICE"
  exit 1
fi

if [[ "$ACCEL" == "auto" ]]; then
  if [[ "$(uname -s)" == "Darwin" ]]; then
    ACCEL="hvf"
  else
    ACCEL="kvm"
  fi
fi

case "$ARCH" in
x64)
  ARGS+=("-machine" "q35")
  ARGS+=("-device" "isa-debug-exit,iobase=0xf4,iosize=0x04")

  # Override the SeaBIOS serial port to keep it from outputting
  # a terminal reset on start.
  ARGS+=("-fw_cfg" "name=etc/sercon-port,string=0")
;;
arm64)
  ARGS+=("-machine" "virt")
;;
*)
  fx-error "Unsupported architecture: $(uname -m)"
  exit 1
esac

if [[ "$ACCEL" == "kvm" ]]; then
  if [[ ! -w "/dev/kvm" ]]; then
    echo "Error: No write permission on /dev/kvm."
    echo "To use KVM acceleration, adjust permissions to /dev/kvm using:"
    echo
    echo "sudo usermod -a -G kvm $USER"
    echo
    echo "Exit the current ssh session.  From the remote host:"
    echo
    echo "exit"
    echo
    echo "On the local host:"
    echo
    echo "ssh <remote_host_name> -O exit"
    echo
    echo "Log back in to remote host and run the emulator again."
    exit 1
  fi
  # TODO(fxbug.dev/33174): Work around KVM bug on AMD Zen machines where SMAP
  # and CPL=3 MMIO accesses trigger a loop in the Linux kernel.
  # TODO(fxbug.dev/63110): Work around KVM bug on AMD Zen machines where XSAVES
  # is enumerated but the IA32_XSS MSR is not available. The bug fix is in
  # 864e2ab2b46db1ac266c46a7c in upstream Linux but has not percolated to
  # popular distributions yet.
  if [[ "$(lsmod | grep kvm_amd)" != "" ]]; then
    # Add topoext to properly report hyperthreading on AMD CPUs
    ARGS+=("-enable-kvm" "-cpu" "host,migratable=no,+invtsc,-smap,-xsaves,+topoext")
  else
    ARGS+=("-enable-kvm" "-cpu" "host,migratable=no,+invtsc")
  fi
  FEATURES+=",KVM"
elif [[ "$ACCEL" == "hvf" ]]; then
  ARGS+=("-enable-hvf" "-cpu" "Haswell")
  FEATURES+=",HVF"
elif [[ "$ACCEL" == "hax" ]]; then
  ARGS+=("-enable-hax" "-cpu" "Haswell")
  FEATURES+=",HAXM"
elif [[ "$ACCEL" == "off" ]]; then
  case "$ARCH" in
  x64)
    ARGS+=("-cpu" "Haswell,+smap,-check,-fsgsbase")
    ;;
  arm64)
    ARGS+=("-cpu" "cortex-a53")
    ;;
  esac
else
  fx-error Unsupported acceleration mode
  exit 1
fi

if (( VULKAN )); then
  FEATURES+=",Vulkan"
else
  FEATURES+=",-Vulkan"
fi

OPTIONS=()
OPTIONS+=("-feature" "$FEATURES")
OPTIONS+=("-window-size" "$WINDOW_SIZE")
OPTIONS+=("-gpu" "$GPU")
OPTIONS+=("-no-location-ui")
if (( DEBUGGER )); then
    OPTIONS+=("-wait-for-debugger")
fi

if (( HEADLESS )); then
    OPTIONS+=("-no-window")
fi

if (( ! HIDPI_SCALING )); then
    OPTIONS+=("-no-hidpi-scaling")
fi

if [[ "$ARCH" == "arm64" ]]; then
  if ! "$EXPERIMENT_ARM64"; then
    fx-error "arm64 support is still experimental, requires --experiment-arm64"
    exit 1
  fi
  OPTIONS+=("-avd-arch" "arm64")
fi

# use port 5556 by default
if (( HTTP )); then
  GRPC="${GRPC:-5556}"
fi

if (( GRPC )); then
  if [[ "$(uname -s)" == "Darwin" ]]; then
    echo "WebRTC feature is not supported on macOS"
    exit 1
  fi
  OPTIONS+=("-grpc" "$GRPC")
  OPTIONS+=("-rtcfps" "$RTCFPS")
  if [[ -n "$TURNCFG" ]]; then
    OPTIONS+=("-turncfg" "$TURNCFG")
  fi
fi

if (( NET )); then
  if [[ "$(uname -s)" == "Darwin" ]]; then
    if [[ -z "$IFNAME" ]]; then
      IFNAME="tap0"
    fi
    if [[ "$IFNAME" != "fakenetwork" && ! -c "/dev/$IFNAME" ]]; then
      echo "To use emu with networking on macOS, install the tun/tap driver:"
      echo "http://tuntaposx.sourceforge.net/download.xhtml"
      exit 1
    fi
    if [[ "$IFNAME" != "fakenetwork" && ! -w "/dev/$IFNAME" ]]; then
      echo "For networking /dev/$IFNAME must be owned by $USER. Please run:"
      echo "  sudo chown $USER /dev/$IFNAME"
      exit 1
    fi
    if [[ -z "${UPSCRIPT}" ]]; then
      echo "sudo follows to configure the tap interface:"
      UPSCRIPT="${DEVSHELL_DIR}"/lib/emu-ifup-macos.sh
    fi
  else
    if [[ -z "$IFNAME" ]]; then
      IFNAME="qemu"
    fi
    TAP_IFS=$(ip tuntap show 2>/dev/null)
    if [[ "$IFNAME" != "fakenetwork" && ! "$TAP_IFS" =~ ${IFNAME}: ]]; then
      echo "To use emu with networking on Linux, configure tun/tap:"
      echo
      echo "sudo ip tuntap add dev $IFNAME mode tap user $USER && \\"
      echo "sudo ip link set $IFNAME up"
      exit 1
    fi
    # Try to detect if a firewall is active. There are only few ways to do that
    # without being root. Unfortunately, using systemd or systemctl does not work
    # (at least on Debian), so use the following hack instead:
    if (command -v ufw && grep -q "^ENABLED=yes" /etc/ufw/ufw.conf) >/dev/null 2>&1; then
      fx-warn "Active firewall detected: If this emulator is unreachable, run: fx setup-ufw"
    fi
    if [[ -z "${UPSCRIPT}" ]]; then
      UPSCRIPT=no
    fi
  fi
  if [[ -n "${UPSCRIPT}" && "${UPSCRIPT}" != "no" && ! -x "${UPSCRIPT}" ]]; then
    echo "The upscript ${UPSCRIPT} is not a valid executable"
    exit 1
  fi
  if [[ -n "${DOWNSCRIPT}" && "${DOWNSCRIPT}" != "no" && ! -x "${DOWNSCRIPT}" ]]; then
    echo "The downscript ${DOWNSCRIPT} is not a valid executable"
    exit 1
  fi
  ARGS+=("-netdev" "type=tap,ifname=$IFNAME,id=net0${UPSCRIPT:+,script=${UPSCRIPT}}${DOWNSCRIPT:+,downscript=${DOWNSCRIPT}}")
  HASH=$(echo $IFNAME | shasum)
  SUFFIX=$(for i in {0..2}; do echo -n ":${HASH:$(( 2 * i )):2}"; done)
  MAC=",mac=52:54:00$SUFFIX"
  ARGS+=("-device" "virtio-net-pci,vectors=8,netdev=net0${MAC}")
else
  ARGS+=("-net" "none")
fi

# Check for X11 on Linux
if [[ "$(uname -s)" == "Linux" ]] && (( ! HEADLESS )); then
  if [[ -z "$DISPLAY" ]]; then
    echo "To use emulator on Linux, start X, or use a virtual framebuffer:"
    echo
    echo "xvfb-run fx emu"
    exit 1
  else
    if [[ "$DISPLAY" != "fakedisplay" ]] && ! xset q >/dev/null 2>&1; then
      echo "clients must be allowed to connect to DISPLAY. Please run:"
      echo
      echo "DISPLAY=$DISPLAY XAUTHORITY=/run/user/`getent passwd | grep /var/lib/gdm | cut -d: -f3`/gdm/Xauthority sudo xhost +"
      echo
      echo "or if using lightdm:"
      echo
      echo "DISPLAY=$DISPLAY XAUTHORITY=/var/run/lightdm/root/$DISPLAY sudo xhost +"
      exit 1
    fi
  fi
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/fuchsia_authorized_keys for SSH access.
img_dir="$(mktemp -d)"
if [[ ! -d "${img_dir}" ]]; then
  fx-error "Failed to create temporary directory"
  exit 1
fi

# Restore the terminal only if the standard input (fd 0) is associated with a
# terminal device. We check this using test operator "-t".
trap 'rm -Rf "${img_dir}"; [[ "${GRPCWEBPROXY_PID}" ]] && kill "${GRPCWEBPROXY_PID}"; [[ -t 0 ]] && stty sane' EXIT

KERNEL_ZBI="${img_dir}/fuchsia-ssh.zbi"
"${ZBI_TOOL}" -o "${KERNEL_ZBI}" "${ZBI_IMAGE}" \
  --entry "data/ssh/authorized_keys=${AUTHORIZED_KEYS}" \
  --type=entropy:64 /dev/urandom

if [[ -n "${FVM_IMAGE}" ]]; then
  fvm_raw="${img_dir}/fvm_raw.blk"
  fx-fvm-extend-image "${FVM_TOOL}" "${FVM_IMAGE}" "${fvm_raw}" "${IMAGE_SIZE}"
  ARGS+=("-drive" "file=${fvm_raw},format=raw,if=none,id=vdisk")
  ARGS+=("-device" "virtio-blk-pci,drive=vdisk")
fi

# Start gRPC web proxy if HTTP port is set
if (( HTTP )); then
  "${GRPCWEBPROXY_DIR}/grpcwebproxy" \
      --backend_addr localhost:"$GRPC" --server_http_debug_port "$HTTP" \
      --backend_tls=false --run_tls_server=false --allow_all_origins &
  GRPCWEBPROXY_PID=$!
fi

# construct the kernel cmd line for aemu
CMDLINE+="kernel.serial=legacy "

# 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 "

# TODO(fxbug.dev/74233): FEMU using HVF accelerator may encounter a race
# condition between VCPU threads which could cause emulator to crash if page
# table eviction is enabled; As a workaround, we disable page table eviction if
# we are using HVF.
if [[ "$ACCEL" == "hvf" ]]; then
  CMDLINE+="kernel.page-scanner.page-table-eviction-policy=never "
fi

# Finally, append any values received via option. We save them for last so that
# they can override others since "last value wins".
CMDLINE+=$OPT_CMDLINE

# run aemu
set -x
"${AEMU_DIR}/${AEMU}" "${OPTIONS[@]}" -fuchsia \
     -kernel "${KERNEL_IMAGE}" \
     -initrd "$KERNEL_ZBI" "${ARGS[@]}" -append "$CMDLINE" "${EMU_ARGS[@]}"