#!/bin/bash
# Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# Script to generate minidump symbols in the format required by
# minidump_stackwalk to dump stack information.
#
# NOTE: This script must be run from the chromeos build chroot environment.
#

SCRIPT_ROOT=$(dirname $(readlink -f "$0"))
. "${SCRIPT_ROOT}/common.sh" || { echo "Unable to load common.sh"; exit 1; }

# Script must be run inside the chroot
restart_in_chroot_if_needed "$@"

get_default_board

# Flags
DEFINE_string board "$DEFAULT_BOARD" "The board to build packages for."
DEFINE_string minidump_symbol_root "" \
  "Symbol root (defaults to /usr/lib/debug/breakpad for board)"
DEFINE_boolean verbose ${FLAGS_FALSE} "Be verbose."

DUMP_SYMS="dump_syms"
DUMP_SYMS32="dump_syms.32"

CUMULATIVE_SIZE=0
ANY_ERRORS=0

SYM_FILE=$(mktemp "/tmp/sym.XXXX")
ERR_FILE=$(mktemp "/tmp/err.XXXX")

function cleanup() {
  rm -f "${SYM_FILE}" "${ERR_FILE}"
}

# Given path to a debug file, return its text file
function get_text_for_debug() {
  local debug_file=$1
  local text_dir=$(dirname "${debug_file#$DEBUG_ROOT}")
  local text_path=${SYSROOT}${text_dir}/$(basename "${debug_file}" .debug)
  echo ${text_path}
}

# Given path to a text file, return its debug file
function get_debug_for_text() {
  local text_file=$1
  local text_path=${text_file#${SYSROOT}}
  local debug_path=${DEBUG_ROOT}${text_path}.debug
  echo ${debug_path}
}

# Returns true if the file given is a 32-bit ELF file.
function is_32b_elf() {
  local elf="$1"
  file "${elf}" | grep -q "ELF 32-bit"
}

# Dump given debug and text file.  Returns 1 if any errors, even
# if they can be ignored, but only sets ANY_ERRORS if the error should not
# be ignored (and we should not proceed to upload).
function dump_file() {
  local debug_file="$1"
  local text_file="$2"
  local debug_directory="$(dirname "${debug_file}")"
  local dump_syms_prog="${DUMP_SYMS}"
  # 32-bit dump_syms must be used to dump a 32-bit ELF file
  if is_32b_elf "${text_file}"; then
    dump_syms_prog="${DUMP_SYMS32}"
    info "Using ${dump_syms_prog} for 32-bit file ${text_file}"
  fi
  # Dump symbols as root in order to read all files.
  if ! sudo "${dump_syms_prog}" "${text_file}" "${debug_directory}" \
       > "${SYM_FILE}" 2> "${ERR_FILE}"; then
    # Try dumping just the main file to get public-only symbols.
    if ! sudo "${dump_syms_prog}" "${text_file}" > "${SYM_FILE}" \
         2> "${ERR_FILE}"; then
      # A lot of files (like kernel files) contain no debug information, do
      # not consider such occurrences as errors.
      if grep -q "file contains no debugging information" "${ERR_FILE}"; then
        warn "No symbols found for ${text_file}"
        return 1
      fi
      error "Unable to dump symbols for ${text_file}:"
      cat "${ERR_FILE}"
      ANY_ERRORS=1
      return 1
    else
      warn "File ${text_file} did not have debug info, using linkage symbols"
    fi
  fi
  local file_id=$(head -1 ${SYM_FILE} | cut -d' ' -f4)
  local module_name=$(head -1 ${SYM_FILE} | cut -d' ' -f5)
  if [ ${FLAGS_verbose} -eq ${FLAGS_TRUE} ]; then
    # Show file upload success and symbol info for easier lookup
    info "Dumped symbols from ${text_file} for ${module_name}|${file_id}."
  fi
  # Sanity check: if we've created the same named file in the /usr/lib/debug
  # directory during the src_compile stage of an ebuild, verify our sym file
  # is the same.
  local installed_sym="${DEBUG_ROOT}"/$(basename "${text_file}").sym
  if [ -e "${installed_sym}" ]; then
    if ! diff "${installed_sym}" "${SYM_FILE}"; then
      error "${installed_sym} differ from current sym file:"
      diff "${installed_sym}" "${SYM_FILE}"
      ANY_ERRORS=1
      return 1
    fi
  fi
  size=$(wc -c "${SYM_FILE}" | cut -d' ' -f1)
  CUMULATIVE_SIZE=$((CUMULATIVE_SIZE + $size))

  local container_dir="${FLAGS_minidump_symbol_root}/${module_name}/${file_id}"
  sudo mkdir -p "${container_dir}"
  sudo mv "${SYM_FILE}" "${container_dir}/${module_name}.sym"
  return 0
}

# Convert the given debug file.  No return value.
function process_file() {
  local debug_file="$1"
  local text_file="$(get_text_for_debug ${debug_file})"
  if [ -h "${debug_file}" ]; then
    # Don't follow symbolic links.  In particular, we don't want to bother
    # with the *.debug links in the "debug/.build-id/" directory.
    if [ ${FLAGS_verbose} -eq ${FLAGS_TRUE} ]; then
      info "Skipping symbolic link: ${debug_file}"
    fi
    return 0
  fi
  if [ "${text_file##*.}" == "ko" ]; then
    # Skip kernel objects.  We can't use their symbols and they sometimes
    # have objects with empty text sections which trigger errors in dump_sym.
    if [ ${FLAGS_verbose} -eq ${FLAGS_TRUE} ]; then
      info "Skipping kernel object: ${text_file}"
    fi
    return 0
  fi
  if [ ! -f "${text_file}" ]; then
    # Allow files to not exist, for instance if they are in the INSTALL_MASK.
    warn "Binary does not exist: ${text_file}"
    return 0
  elif [ ! -r "${text_file}" ]; then
    # Allow files to not be readable, for instance setuid programs like passwd
    warn "Binary is not readable: ${text_file}"
    return 0
  fi

  dump_file "${debug_file}" "${text_file}"
}

function main() {
  trap cleanup EXIT

  # Parse command line
  FLAGS_HELP="usage: $0 [flags] [<files...>]"
  FLAGS "$@" || exit 1
  eval set -- "${FLAGS_ARGV}"

  set -e

  [ -n "$FLAGS_board" ] ||  die "--board is required."

  SYSROOT="/build/${FLAGS_board}"

  if [[ -z "${FLAGS_minidump_symbol_root}" ]]; then
    FLAGS_minidump_symbol_root="${SYSROOT}/usr/lib/debug/breakpad"
  fi

  info "Writing minidump symbols to ${FLAGS_minidump_symbol_root}"

  DEBUG_ROOT="${SYSROOT}/usr/lib/debug"
  CUMULATIVE_SIZE=0
  sudo rm -rf "${FLAGS_minidump_symbol_root}"

  if [ -z "${FLAGS_ARGV}" ]; then
    for debug_file in $(find "${DEBUG_ROOT}" -name \*.debug); do
      ! process_file "${debug_file}"
    done
  else
    for either_file in ${FLAGS_ARGV}; do
      either_file=${either_file#\'}
      either_file=${either_file%\'}
      if [ ! -h "${either_file}" -a ! -f "${either_file}" ]; then
        error "Specified file ${either_file} does not exist"
        ANY_ERRORS=1
        continue
      fi
      if [ "${either_file##*.}" == "debug" ]; then
        debug_file="${either_file}"
      else
        debug_file="$(get_debug_for_text ${either_file})"
      fi
      ! process_file "${debug_file}"
    done
  fi

  info "Generated ${CUMULATIVE_SIZE}B of debug information"

  [ ${ANY_ERRORS} -ne 0 ] && die "Encountered problems"
  return 0
}

main "$@"