通过使用 Prelink 优化程序启动速度

#!/bin/bash

 

#=========================================================

# Author         : Junjie Huang

# Email          : acm@gmail.com

# Last modified  : 2018-05-07 17:43

# Filename       : elf_dependencies_analyzer.sh

# Description    : a tool to analyze dependencies for elf

#=========================================================

 

ROOT_ELF=""

MAX_DEPTH=0

SYS_ROOT=$(pwd)

LD_LIB_PATH=""

CHECK_PRELINK=0

PRINT_PATH=0

IGNORE_SCANNED=0

DRAW_WITH_DOT=0

SAVE_IN_CSV=0

 

function usage() {

  echo -e "\nUsage : `basename $0` [OPTION...] [FILES]"

  echo "Note :"

  echo "    -c                                 Check if the elf file has been prelinked or not"

  echo "    -p                                 Print the path of elf; otherwise print name as default"

  echo "    -i                                 Ignore the elf file which has been scanned, to be unique"

  echo "    -g | --graph                       Draw the dependencies graphs with graphviz and dot"

  echo "    -t | --table                       Generate the depencies table in cvs format"

  echo "    -h | --help                        Get help"

  echo "    --depth=MAX_DEPTH                  The max depth to scan"

  echo "    --root=ROOT_PATH                   Prefix all paths with ROOT_PATH "

  echo "    --ld-library-path=LD_LIBRARY_PATH  What LD_LIBRARY_PATH should be used"

  echo ""

}

 

if [[ $# -lt 1 ]]; then

  usage

  exit 1

fi

 

# parse the arguments

for i in "$@"; do

  case $i in

    -c)

      CHECK_PRELINK=1

      shift

      ;;

    -p)

      PRINT_PATH=1

      shift

      ;;

    -i)

      IGNORE_SCANNED=1

      shift

      ;;

    -g|--graph)

      DRAW_WITH_DOT=1

      shift

      ;;

    -t|--table)

      SAVE_IN_CSV=1

      shift

      ;;

    -d=*|--depth=*)

      MAX_DEPTH="${i#*=}"

      shift

      ;;

    -r=*|--root=*)

      SYS_ROOT="${i#*=}"

      shift

      ;;

    -l=*|--ld-library-path=*)

      LD_LIB_PATH="${i#*=}"

      shift

      ;;

    -h|--help)

      usage

      exit 1

      ;;

    *)

      ROOT_ELF=$i

      ;;

  esac

done

 

ROOT_ELF_PATH=${SYS_ROOT}${ROOT_ELF}

ROOT_ELF_NAME=$(basename ${ROOT_ELF_PATH})

LD_LIB_LIST=($(echo ${LD_LIB_PATH} | tr : ' '))

 

 

DOT_SOURCE_FILE=${ROOT_ELF_NAME}".dot"

DOT_OUTPUT_FILE=${ROOT_ELF_NAME}".png"

CSV_SOURCE_FILE=${ROOT_ELF_NAME}".csv"

 

BLACK=$(tput setaf 0)

RED=$(tput setaf 1)

GREEN=$(tput setaf 2)

YELLOW=$(tput setaf 3)

BLUE=$(tput setaf 4)

MAGENTA=$(tput setaf 5)

CYAN=$(tput setaf 6)

WHITE=$(tput setaf 7)

RESET=$(tput sgr0)

 

last_child_mask=()

scanned_elf_list=()

 

function print_hierarchy_symbols() {

  if [[ $depth -gt 0 ]]; then

    local i=1

    while [[ $i -lt $depth ]]; do

      if [[ ${last_child_mask[$i]} -eq 0 ]]; then

        echo -n '│  '

      else

        echo -n '   '

      fi

      i=$((i+1))

    done

 

    if [[ ${last_child_mask[$depth]} -eq 0 ]]; then

      echo -n '├──'

    else

      echo -n '└──'

    fi

  fi

}

 

# PARAMETER 1: ELF file path

function print_file_path() {

  local path=$1

  local name=$(basename $path)

 

  if [[ SAVE_IN_CSV -eq 1 ]]; then

    save_in_cvs ${name}

  fi

 

  print_hierarchy_symbols

 

  if [[ ${CHECK_PRELINK} -eq 1 ]]; then

    if [[ $(readelf -S ${path} | grep -i "prelink") ]]; then

      if [[ ${PRINT_PATH} -eq 1 ]]; then

        echo "${GREEN}${path} [y]${RESET}"

      else

        echo "${GREEN}${name} [y]${RESET}"

      fi

    else

      if [[ ${PRINT_PATH} -eq 1 ]]; then

        echo "${RED}${path} [n]${RESET}"

      else

        echo "${RED}${name} [n]${RESET}"

      fi

    fi

  else

    if [[ ${PRINT_PATH} -eq 1 ]]; then

      echo "${MAGENTA}${path}${RESET}"

    else

      echo "${MAGENTA}${name}${RESET}"

    fi

  fi

}

 

function generate_dot_header() {

  if [[ -f ${DOT_SOURCE_FILE} ]]; then

    rm -rf ${DOT_SOURCE_FILE}

  fi

 

  cat << EOT >> ${DOT_SOURCE_FILE}

digraph "${ROOT_ELF_NAME}" {

  graph [

    rankdir=LR

    bgcolor=white

    fontsize=10

  ]

  edge [

    color=blue

  ]

  node [

    shape=record

    fontcolor=red

    color=black

    style=filled

    fillcolor=white

  ]

EOT

}

 

# PARAMETER 1: parent elf path

# PARAMETER 2: current elf path

function draw_in_dot() {

  local pre=$(basename $1)

  local cur=$(basename $2)

  echo "  \"$pre\" -> \"$cur\";" >> ${DOT_SOURCE_FILE}

}

 

function generate_dot_footer() {

  echo "}" >> ${DOT_SOURCE_FILE}

}

 

# PARAMETER 1: ELF file name

function save_in_cvs() {

  local elf=$1

  if [[ $depth -gt 0 ]]; then

    local i=1

    while [[ $i -le $depth ]]; do

      echo -n ', ' >> ${CSV_SOURCE_FILE}

      i=$((i+1))

    done

  fi

  echo $elf >> ${CSV_SOURCE_FILE}

}

 

# PARAMETER 1: ELF file path

function list_dependencies() {

  local elf_list=$(readelf -d $1 | grep NEEDED | \

    awk -F'[' '{print $2}' | awk -F']' '{print $1}')

  echo ${elf_list}

}

 

depth=0

 

# PARAMETER 1: ELF file path

function dependencies_scan() {

  local target=$1

  local dep_list=($(list_dependencies ${target})) #array

 

  if [[ ${IGNORE_SCANNED} -eq 1 ]]; then

    if [[ ${scanned_elf_list[@]} =~ (^|[[:space:]])"${target}"($|[[:space:]]) ]]; then

      return

    else

      scanned_elf_list+=(${target})

    fi

  fi

 

  for elf_name in "${dep_list[@]}"; do

    local file_list=()

 

    if [[ ${#LD_LIB_LIST[@]} -ne 0 ]]; then

      for lib in "${LD_LIB_LIST[@]}"; do

        lib=${SYS_ROOT}${lib}

        if [[ -d ${lib} ]]; then

          file_list=($(find ${lib} -name ${elf_name}))

          if [[ ${#file_list[@]} -ne 0 ]]; then

            break

          fi

        fi

      done

    else

      file_list=($(find . -name ${elf_name}))

    fi

 

    if [[ ${#file_list[@]} -eq 0 ]]; then

      #file_list=($(find . -name ${elf_name}))

      #echo "could not found ${elf_name}"

      continue

    fi

 

    ((depth++))

 

    if [[ ${dep_list[-1]} = ${elf_name} ]]; then

      last_child_mask[$depth]=1

    else

      last_child_mask[$depth]=0

    fi

 

    file_path=${file_list[0]}

    print_file_path ${file_path}

    if [[ ${DRAW_WITH_DOT} -eq 1 ]]; then

      draw_in_dot ${target} ${file_path}

    fi

 

    if [[ $(echo ${file_path} | grep "") ]]; then

      dependencies_scan ${file_path}

    elif [[ $depth -lt ${MAX_DEPTH} ]]; then

      dependencies_scan ${file_path}

    fi

 

    ((depth--))

  done

}

 

function main() {

  if [[ ${DRAW_WITH_DOT} -eq 1 ]]; then

    generate_dot_header

  fi

 

  if [[ ${SAVE_IN_CSV} -eq 1 ]]; then

    rm -rf ${CSV_SOURCE_FILE}

  fi

 

  print_file_path ${ROOT_ELF_PATH}

  dependencies_scan ${ROOT_ELF_PATH}

 

  if [[ ${DRAW_WITH_DOT} -eq 1 ]]; then

    generate_dot_footer

    if [[ $(which dot) ]]; then

      dot -Tpng -o ${DOT_OUTPUT_FILE} ${DOT_SOURCE_FILE}

    else

      echo "Could not find \"dot\" command, please install graphviz!"

    fi

  fi

}

 

main