#!/bin/bash
#===- lib/asan/scripts/asan_device_setup -----------------------------------===#
#
# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
# See https://llvm.org/LICENSE.txt for license information.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#
# Prepare Android device to run ASan applications.
#
#===------------------------------------------------------------------------===#

set -e

HERE="$(cd "$(dirname "$0")" && pwd)"

revert=no
extra_options=
device=
lib=
use_su=0

function usage {
    echo "usage: $0 [--revert] [--device device-id] [--lib path] [--extra-options options]"
    echo "  --revert: Uninstall ASan from the device."
    echo "  --lib: Path to ASan runtime library."
    echo "  --extra-options: Extra ASAN_OPTIONS."
    echo "  --device: Install to the given device. Use 'adb devices' to find"
    echo "            device-id."
    echo "  --use-su: Use 'su -c' prefix for every adb command instead of using"
    echo "            'adb root' once."
    echo
    exit 1
}

function adb_push {
  if [ $use_su -eq 0 ]; then
    $ADB push "$1" "$2"
  else
    local FILENAME=$(basename $1)
    $ADB push "$1" "/data/local/tmp/$FILENAME"
    $ADB shell su -c "rm \\\"$2/$FILENAME\\\"" >&/dev/null
    $ADB shell su -c "cat \\\"/data/local/tmp/$FILENAME\\\" > \\\"$2/$FILENAME\\\""
    $ADB shell su -c "rm \\\"/data/local/tmp/$FILENAME\\\""
  fi
}

function adb_remount {
  if [ $use_su -eq 0 ]; then
    $ADB remount
  else
    local STORAGE=`$ADB shell mount | grep /system | cut -d ' ' -f1`
    if [ "$STORAGE" != "" ]; then
      echo Remounting $STORAGE at /system
      $ADB shell su -c "mount -o rw,remount $STORAGE /system"
    else
      echo Failed to get storage device name for "/system" mount point
    fi
  fi
}

function adb_shell {
  if [ $use_su -eq 0 ]; then
    $ADB shell $@
  else
    $ADB shell su -c "$*"
  fi
}

function adb_root {
  if [ $use_su -eq 0 ]; then
    $ADB root
  fi
}

function adb_wait_for_device {
  $ADB wait-for-device
}

function adb_pull {
  if [ $use_su -eq 0 ]; then
    $ADB pull "$1" "$2"
  else
    local FILENAME=$(basename $1)
    $ADB shell rm "/data/local/tmp/$FILENAME" >&/dev/null
    $ADB shell su -c "[ -f \\\"$1\\\" ] && cat \\\"$1\\\" > \\\"/data/local/tmp/$FILENAME\\\" && chown root.shell \\\"/data/local/tmp/$FILENAME\\\" && chmod 755 \\\"/data/local/tmp/$FILENAME\\\"" &&
    $ADB pull "/data/local/tmp/$FILENAME" "$2" >&/dev/null && $ADB shell "rm \"/data/local/tmp/$FILENAME\""
  fi
}

function get_device_arch { # OUT OUT64
    local _outvar=$1
    local _outvar64=$2
    local _ABI=$(adb_shell getprop ro.product.cpu.abi)
    local _ARCH=
    local _ARCH64=
    if [[ $_ABI == x86* ]]; then
        _ARCH=i386
    elif [[ $_ABI == armeabi* ]]; then
        _ARCH=arm
    elif [[ $_ABI == arm64-v8a* ]]; then
        _ARCH=arm
        _ARCH64=aarch64
    else
        echo "Unrecognized device ABI: $_ABI"
        exit 1
    fi
    eval $_outvar=\$_ARCH
    eval $_outvar64=\$_ARCH64
}

while [[ $# > 0 ]]; do
  case $1 in
    --revert)
      revert=yes
      ;;
    --extra-options)
      shift
      if [[ $# == 0 ]]; then
        echo "--extra-options requires an argument."
        exit 1
      fi
      extra_options="$1"
      ;;
    --lib)
      shift
      if [[ $# == 0 ]]; then
        echo "--lib requires an argument."
        exit 1
      fi
      lib="$1"
      ;;
    --device)
      shift
      if [[ $# == 0 ]]; then
        echo "--device requires an argument."
        exit 1
      fi
      device="$1"
      ;;
    --use-su)
      use_su=1
      ;;
    *)
      usage
      ;;
  esac
  shift
done

ADB=${ADB:-adb}
if [[ x$device != x ]]; then
    ADB="$ADB -s $device"
fi

if [ $use_su -eq 1 ]; then
  # Test if 'su' is present on the device
  SU_TEST_OUT=`$ADB shell su -c "echo foo" 2>&1 | sed 's/\r$//'`
  if [ $? != 0 -o "$SU_TEST_OUT" != "foo" ]; then
    echo "ERROR: Cannot use 'su -c':"
    echo "$ adb shell su -c \"echo foo\""
    echo $SU_TEST_OUT
    echo "Check that 'su' binary is correctly installed on the device or omit"
    echo "            --use-su flag"
    exit 1
  fi
fi

echo '>> Remounting /system rw'
adb_wait_for_device
adb_root
adb_wait_for_device
adb_remount
adb_wait_for_device

get_device_arch ARCH ARCH64
echo "Target architecture: $ARCH"
ASAN_RT="libclang_rt.asan-$ARCH-android.so"
if [[ -n $ARCH64 ]]; then
  echo "Target architecture: $ARCH64"
  ASAN_RT64="libclang_rt.asan-$ARCH64-android.so"
fi

RELEASE=$(adb_shell getprop ro.build.version.release)
PRE_L=0
if echo "$RELEASE" | grep '^4\.' >&/dev/null; then
    PRE_L=1
fi
ANDROID_O=0
if echo "$RELEASE" | grep '^8\.0\.' >&/dev/null; then
    # 8.0.x is for Android O
    ANDROID_O=1
fi

if [[ x$revert == xyes ]]; then
    echo '>> Uninstalling ASan'

    if ! adb_shell ls -l /system/bin/app_process | grep -o '\->.*app_process' >&/dev/null; then
      echo '>> Pre-L device detected.'
      adb_shell mv /system/bin/app_process.real /system/bin/app_process
      adb_shell rm /system/bin/asanwrapper
    elif ! adb_shell ls -l /system/bin/app_process64.real | grep -o 'No such file or directory' >&/dev/null; then
      # 64-bit installation.
      adb_shell mv /system/bin/app_process32.real /system/bin/app_process32
      adb_shell mv /system/bin/app_process64.real /system/bin/app_process64
      adb_shell rm /system/bin/asanwrapper
      adb_shell rm /system/bin/asanwrapper64
    else
      # 32-bit installation.
      adb_shell rm /system/bin/app_process.wrap
      adb_shell rm /system/bin/asanwrapper
      adb_shell rm /system/bin/app_process
      adb_shell ln -s /system/bin/app_process32 /system/bin/app_process
    fi

    if [[ ANDROID_O -eq 1 ]]; then
      adb_shell mv /system/etc/ld.config.txt.saved /system/etc/ld.config.txt
    fi

    echo '>> Restarting shell'
    adb_shell stop
    adb_shell start

    # Remove the library on the last step to give a chance to the 'su' binary to
    # be executed without problem.
    adb_shell rm /system/lib/$ASAN_RT

    echo '>> Done'
    exit 0
fi

if [[ -d "$lib" ]]; then
    ASAN_RT_PATH="$lib"
elif [[ -f "$lib" && "$lib" == *"$ASAN_RT" ]]; then
    ASAN_RT_PATH=$(dirname "$lib")
elif [[ -f "$HERE/$ASAN_RT" ]]; then
    ASAN_RT_PATH="$HERE"
elif [[ $(basename "$HERE") == "bin" ]]; then
    # We could be in the toolchain's base directory.
    # Consider ../lib, ../lib/asan, ../lib/linux,
    # ../lib/clang/$VERSION/lib/linux, and ../lib64/clang/$VERSION/lib/linux.
    P=$(ls "$HERE"/../lib/"$ASAN_RT" \
           "$HERE"/../lib/asan/"$ASAN_RT" \
           "$HERE"/../lib/linux/"$ASAN_RT" \
           "$HERE"/../lib/clang/*/lib/linux/"$ASAN_RT" \
           "$HERE"/../lib64/clang/*/lib/linux/"$ASAN_RT" 2>/dev/null | sort | tail -1)
    if [[ -n "$P" ]]; then
        ASAN_RT_PATH="$(dirname "$P")"
    fi
fi

if [[ -z "$ASAN_RT_PATH" || ! -f "$ASAN_RT_PATH/$ASAN_RT" ]]; then
    echo ">> ASan runtime library not found"
    exit 1
fi

if [[ -n "$ASAN_RT64" ]]; then
  if [[ -z "$ASAN_RT_PATH" || ! -f "$ASAN_RT_PATH/$ASAN_RT64" ]]; then
    echo ">> ASan runtime library not found"
    exit 1
  fi
fi

TMPDIRBASE=$(mktemp -d)
TMPDIROLD="$TMPDIRBASE/old"
TMPDIR="$TMPDIRBASE/new"
mkdir "$TMPDIROLD"

if ! adb_shell ls -l /system/bin/app_process | grep -o '\->.*app_process' >&/dev/null; then

    if adb_pull /system/bin/app_process.real /dev/null >&/dev/null; then
        echo '>> Old-style ASan installation detected. Reverting.'
        adb_shell mv /system/bin/app_process.real /system/bin/app_process
    fi

    echo '>> Pre-L device detected. Setting up app_process symlink.'
    adb_shell mv /system/bin/app_process /system/bin/app_process32
    adb_shell ln -s /system/bin/app_process32 /system/bin/app_process
fi

echo '>> Copying files from the device'
if [[ -n "$ASAN_RT64" ]]; then
  adb_pull /system/lib/"$ASAN_RT" "$TMPDIROLD" || true
  adb_pull /system/lib64/"$ASAN_RT64" "$TMPDIROLD" || true
  adb_pull /system/bin/app_process32 "$TMPDIROLD" || true
  adb_pull /system/bin/app_process32.real "$TMPDIROLD" || true
  adb_pull /system/bin/app_process64 "$TMPDIROLD" || true
  adb_pull /system/bin/app_process64.real "$TMPDIROLD" || true
  adb_pull /system/bin/asanwrapper "$TMPDIROLD" || true
  adb_pull /system/bin/asanwrapper64 "$TMPDIROLD" || true
else
  adb_pull /system/lib/"$ASAN_RT" "$TMPDIROLD" || true
  adb_pull /system/bin/app_process32 "$TMPDIROLD" || true
  adb_pull /system/bin/app_process.wrap "$TMPDIROLD" || true
  adb_pull /system/bin/asanwrapper "$TMPDIROLD" || true
fi
cp -r "$TMPDIROLD" "$TMPDIR"

if [[ -f "$TMPDIR/app_process.wrap" || -f "$TMPDIR/app_process64.real" ]]; then
    echo ">> Previous installation detected"
else
    echo ">> New installation"
fi

echo '>> Generating wrappers'

cp "$ASAN_RT_PATH/$ASAN_RT" "$TMPDIR/"
if [[ -n "$ASAN_RT64" ]]; then
  cp "$ASAN_RT_PATH/$ASAN_RT64" "$TMPDIR/"
fi

ASAN_OPTIONS=start_deactivated=1

# The name of a symlink to libclang_rt.asan-$ARCH-android.so used in LD_PRELOAD.
# The idea is to have the same name in lib and lib64 to keep it from falling
# apart when a 64-bit process spawns a 32-bit one, inheriting the environment.
ASAN_RT_SYMLINK=symlink-to-libclang_rt.asan

function generate_zygote_wrapper { # from, to
  local _from=$1
  local _to=$2
  if [[ PRE_L -eq 0 ]]; then
    # LD_PRELOAD parsing is broken in N if it starts with ":". Luckily, it is
    # unset in the system environment since L.
    local _ld_preload=$ASAN_RT_SYMLINK
  else
    local _ld_preload=\$LD_PRELOAD:$ASAN_RT_SYMLINK
  fi
  cat <<EOF >"$TMPDIR/$_from"
#!/system/bin/sh-from-zygote
ASAN_OPTIONS=$ASAN_OPTIONS \\
ASAN_ACTIVATION_OPTIONS=include_if_exists=/data/local/tmp/asan.options.%b \\
LD_PRELOAD=$_ld_preload \\
exec $_to "\$@"

EOF
}

# On Android-L not allowing user segv handler breaks some applications.
# Since ~May 2017 this is the default setting; included for compatibility with
# older library versions.
if [[ PRE_L -eq 0 ]]; then
    ASAN_OPTIONS="$ASAN_OPTIONS,allow_user_segv_handler=1"
fi

if [[ x$extra_options != x ]] ; then
    ASAN_OPTIONS="$ASAN_OPTIONS,$extra_options"
fi

# Zygote wrapper.
if [[ -f "$TMPDIR/app_process64" ]]; then
  # A 64-bit device.
  if [[ ! -f "$TMPDIR/app_process64.real" ]]; then
    # New installation.
    mv "$TMPDIR/app_process32" "$TMPDIR/app_process32.real"
    mv "$TMPDIR/app_process64" "$TMPDIR/app_process64.real"
  fi
  generate_zygote_wrapper "app_process32" "/system/bin/app_process32.real"
  generate_zygote_wrapper "app_process64" "/system/bin/app_process64.real"
else
  # A 32-bit device.
  generate_zygote_wrapper "app_process.wrap" "/system/bin/app_process32"
fi

# General command-line tool wrapper (use for anything that's not started as
# zygote).
cat <<EOF >"$TMPDIR/asanwrapper"
#!/system/bin/sh
LD_PRELOAD=$ASAN_RT_SYMLINK \\
exec \$@

EOF

if [[ -n "$ASAN_RT64" ]]; then
  cat <<EOF >"$TMPDIR/asanwrapper64"
#!/system/bin/sh
LD_PRELOAD=$ASAN_RT_SYMLINK \\
exec \$@

EOF
fi

function install { # from, to, chmod, chcon
  local _from=$1
  local _to=$2
  local _mode=$3
  local _context=$4
  local _basename="$(basename "$_from")"
  echo "Installing $_to/$_basename $_mode $_context"
  adb_push "$_from" "$_to/$_basename"
  adb_shell chown root.shell "$_to/$_basename"
  if [[ -n "$_mode" ]]; then
    adb_shell chmod "$_mode" "$_to/$_basename"
  fi
  if [[ -n "$_context" ]]; then
    adb_shell chcon "$_context" "$_to/$_basename"
  fi
}

if ! ( cd "$TMPDIRBASE" && diff -qr old/ new/ ) ; then
    # Make SELinux happy by keeping app_process wrapper and the shell
    # it runs on in zygote domain.
    ENFORCING=0
    if adb_shell getenforce | grep Enforcing >/dev/null; then
        # Sometimes shell is not allowed to change file contexts.
        # Temporarily switch to permissive.
        ENFORCING=1
        adb_shell setenforce 0
    fi

    if [[ PRE_L -eq 1 ]]; then
        CTX=u:object_r:system_file:s0
    else
        CTX=u:object_r:zygote_exec:s0
    fi

    echo '>> Pushing files to the device'

    if [[ -n "$ASAN_RT64" ]]; then
      install "$TMPDIR/$ASAN_RT" /system/lib 644
      install "$TMPDIR/$ASAN_RT64" /system/lib64 644
      install "$TMPDIR/app_process32" /system/bin 755 $CTX
      install "$TMPDIR/app_process32.real" /system/bin 755 $CTX
      install "$TMPDIR/app_process64" /system/bin 755 $CTX
      install "$TMPDIR/app_process64.real" /system/bin 755 $CTX
      install "$TMPDIR/asanwrapper" /system/bin 755
      install "$TMPDIR/asanwrapper64" /system/bin 755

      adb_shell rm -f /system/lib/$ASAN_RT_SYMLINK
      adb_shell ln -s $ASAN_RT /system/lib/$ASAN_RT_SYMLINK
      adb_shell rm -f /system/lib64/$ASAN_RT_SYMLINK
      adb_shell ln -s $ASAN_RT64 /system/lib64/$ASAN_RT_SYMLINK
    else
      install "$TMPDIR/$ASAN_RT" /system/lib 644
      install "$TMPDIR/app_process32" /system/bin 755 $CTX
      install "$TMPDIR/app_process.wrap" /system/bin 755 $CTX
      install "$TMPDIR/asanwrapper" /system/bin 755 $CTX

      adb_shell rm -f /system/lib/$ASAN_RT_SYMLINK
      adb_shell ln -s $ASAN_RT /system/lib/$ASAN_RT_SYMLINK

      adb_shell rm /system/bin/app_process
      adb_shell ln -s /system/bin/app_process.wrap /system/bin/app_process
    fi

    adb_shell cp /system/bin/sh /system/bin/sh-from-zygote
    adb_shell chcon $CTX /system/bin/sh-from-zygote

    if [[ ANDROID_O -eq 1 ]]; then
      # For Android O, the linker namespace is temporarily disabled.
      adb_shell mv /system/etc/ld.config.txt /system/etc/ld.config.txt.saved
    fi

    if [ $ENFORCING == 1 ]; then
        adb_shell setenforce 1
    fi

    echo '>> Restarting shell (asynchronous)'
    adb_shell stop
    adb_shell start

    echo '>> Please wait until the device restarts'
else
    echo '>> Device is up to date'
fi

rm -r "$TMPDIRBASE"