#!/bin/bash -e

# Copyright (c) 2012 The Chromium 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 install everything needed to build chromium (well, ideally, anyway)
# See http://code.google.com/p/chromium/wiki/LinuxBuildInstructions
# and http://code.google.com/p/chromium/wiki/LinuxBuild64Bit

usage() {
  echo "Usage: $0 [--options]"
  echo "Options:"
  echo "--[no-]syms: enable or disable installation of debugging symbols"
  echo "--[no-]lib32: enable or disable installation of 32 bit libraries"
  echo "--[no-]arm: enable or disable installation of arm cross toolchain"
  echo "--[no-]chromeos-fonts: enable or disable installation of Chrome OS"\
       "fonts"
  echo "--[no-]nacl: enable or disable installation of prerequisites for"\
       "building standalone NaCl and all its toolchains"
  echo "--no-prompt: silently select standard options/defaults"
  echo "--quick-check: quickly try to determine if dependencies are installed"
  echo "               (this avoids interactive prompts and sudo commands,"
  echo "               so might not be 100% accurate)"
  echo "--unsupported: attempt installation even on unsupported systems"
  echo "Script will prompt interactively if options not given."
  exit 1
}

# Checks whether a particular package is available in the repos.
# USAGE: $ package_exists <package name>
package_exists() {
  apt-cache pkgnames | grep -x "$1" > /dev/null 2>&1
}

# These default to on because (some) bots need them and it keeps things
# simple for the bot setup if all bots just run the script in its default
# mode.  Developers who don't want stuff they don't need installed on their
# own workstations can pass --no-arm --no-nacl when running the script.
do_inst_arm=1
do_inst_nacl=1

while test "$1" != ""
do
  case "$1" in
  --syms)                   do_inst_syms=1;;
  --no-syms)                do_inst_syms=0;;
  --lib32)                  do_inst_lib32=1;;
  --no-lib32)               do_inst_lib32=0;;
  --arm)                    do_inst_arm=1;;
  --no-arm)                 do_inst_arm=0;;
  --chromeos-fonts)         do_inst_chromeos_fonts=1;;
  --no-chromeos-fonts)      do_inst_chromeos_fonts=0;;
  --nacl)                   do_inst_nacl=1;;
  --no-nacl)                do_inst_nacl=0;;
  --no-prompt)              do_default=1
                            do_quietly="-qq --assume-yes"
    ;;
  --quick-check)            do_quick_check=1;;
  --unsupported)            do_unsupported=1;;
  *) usage;;
  esac
  shift
done

ubuntu_versions="12\.04|12\.10|13\.04|13\.10"
ubuntu_codenames="precise|quantal|raring|saucy"
ubuntu_issue="Ubuntu ($ubuntu_versions|$ubuntu_codenames)"
# GCEL is an Ubuntu-derived VM image used on Google Compute Engine; /etc/issue
# doesn't contain a version number so just trust that the user knows what
# they're doing.
gcel_issue="^GCEL"

if [ 0 -eq "${do_unsupported-0}" ] && [ 0 -eq "${do_quick_check-0}" ] ; then
  if ! egrep -q "($ubuntu_issue|$gcel_issue)" /etc/issue; then
    echo "ERROR: Only Ubuntu 12.04 (precise) through 13.10 (saucy) are"\
        "currently supported" >&2
    exit 1
  fi

  if ! uname -m | egrep -q "i686|x86_64"; then
    echo "Only x86 architectures are currently supported" >&2
    exit
  fi
fi

if [ "x$(id -u)" != x0 ] && [ 0 -eq "${do_quick_check-0}" ]; then
  echo "Running as non-root user."
  echo "You might have to enter your password one or more times for 'sudo'."
  echo
fi

# Packages needed for chromeos only
chromeos_dev_list="libbluetooth-dev"

# Packages needed for development
dev_list="apache2.2-bin bison curl dpkg-dev elfutils fakeroot flex g++ git-core
          gperf language-pack-da language-pack-fr language-pack-he
          language-pack-zh-hant libapache2-mod-php5 libasound2-dev libbrlapi-dev
          libbz2-dev libcairo2-dev libcap-dev libcups2-dev libcurl4-gnutls-dev
          libdrm-dev libelf-dev libgconf2-dev libgl1-mesa-dev libglib2.0-dev
          libglu1-mesa-dev libgnome-keyring-dev libgtk2.0-dev libkrb5-dev
          libnspr4-dev libnss3-dev libpam0g-dev libpci-dev libpulse-dev
          libsctp-dev libspeechd-dev libsqlite3-dev libssl-dev libudev-dev
          libwww-perl libxslt1-dev libxss-dev libxt-dev libxtst-dev
          mesa-common-dev openbox patch perl php5-cgi pkg-config python
          python-cherrypy3 python-dev python-psutil rpm ruby subversion
          ttf-dejavu-core ttf-indic-fonts ttf-kochi-gothic ttf-kochi-mincho
          wdiff xfonts-mathml $chromeos_dev_list"

# 64-bit systems need a minimum set of 32-bit compat packages for the pre-built
# NaCl binaries. These are always needed, regardless of whether or not we want
# the full 32-bit "cross-compile" support (--lib32).
if file /sbin/init | grep -q 'ELF 64-bit'; then
  dev_list="${dev_list} libc6-i386 lib32gcc1 lib32stdc++6"
fi

# Run-time libraries required by chromeos only
chromeos_lib_list="libpulse0 libbz2-1.0"

# Full list of required run-time libraries
lib_list="libatk1.0-0 libc6 libasound2 libcairo2 libcap2 libcups2 libexpat1
          libfontconfig1 libfreetype6 libglib2.0-0 libgnome-keyring0
          libgtk2.0-0 libpam0g libpango1.0-0 libpci3 libpcre3 libpixman-1-0
          libpng12-0 libspeechd2 libstdc++6 libsqlite3-0 libx11-6
          libxau6 libxcb1 libxcomposite1 libxcursor1 libxdamage1 libxdmcp6
          libxext6 libxfixes3 libxi6 libxinerama1 libxrandr2 libxrender1
          libxtst6 zlib1g $chromeos_lib_list"

# Debugging symbols for all of the run-time libraries
dbg_list="libatk1.0-dbg libc6-dbg libcairo2-dbg libfontconfig1-dbg
          libglib2.0-0-dbg libgtk2.0-0-dbg libpango1.0-0-dbg libpcre3-dbg
          libpixman-1-0-dbg libsqlite3-0-dbg libx11-6-dbg libxau6-dbg
          libxcb1-dbg libxcomposite1-dbg libxcursor1-dbg libxdamage1-dbg
          libxdmcp6-dbg libxext6-dbg libxfixes3-dbg libxi6-dbg libxinerama1-dbg
          libxrandr2-dbg libxrender1-dbg libxtst6-dbg zlib1g-dbg
          libstdc++6-4.6-dbg"

# arm cross toolchain packages needed to build chrome on armhf
arm_list="libc6-armhf-cross libc6-dev-armhf-cross libgcc1-armhf-cross
          libgomp1-armhf-cross linux-libc-dev-armhf-cross
          libgcc1-dbg-armhf-cross libgomp1-dbg-armhf-cross
          binutils-arm-linux-gnueabihf cpp-arm-linux-gnueabihf
          gcc-arm-linux-gnueabihf g++-arm-linux-gnueabihf
          libmudflap0-dbg-armhf-cross"

# Old armel cross toolchain packages
armel_list="libc6-armel-cross libc6-dev-armel-cross libgcc1-armel-cross
            libgomp1-armel-cross linux-libc-dev-armel-cross
            libgcc1-dbg-armel-cross libgomp1-dbg-armel-cross
            binutils-arm-linux-gnueabi cpp-arm-linux-gnueabi
            gcc-arm-linux-gnueabi g++-arm-linux-gnueabi
            libmudflap0-dbg-armel-cross"

# TODO(sbc): remove armel once the armhf transition is complete
arm_list="$arm_list $armel_list"

# Packages to build standalone NaCl and all its toolchains.
nacl_list="g++-mingw-w64-i686 libtinfo-dev:i386"

# Some package names have changed over time
if package_exists ttf-mscorefonts-installer; then
  dev_list="${dev_list} ttf-mscorefonts-installer"
else
  dev_list="${dev_list} msttcorefonts"
fi
if package_exists libnspr4-dbg; then
  dbg_list="${dbg_list} libnspr4-dbg libnss3-dbg"
  lib_list="${lib_list} libnspr4 libnss3"
else
  dbg_list="${dbg_list} libnspr4-0d-dbg libnss3-1d-dbg"
  lib_list="${lib_list} libnspr4-0d libnss3-1d"
fi
if package_exists libjpeg-dev; then
  dev_list="${dev_list} libjpeg-dev"
else
  dev_list="${dev_list} libjpeg62-dev"
fi
if package_exists libudev1; then
  dev_list="${dev_list} libudev1"
else
  dev_list="${dev_list} libudev0"
fi
if package_exists libbrlapi0.6; then
  dev_list="${dev_list} libbrlapi0.6"
else
  dev_list="${dev_list} libbrlapi0.5"
fi


# Some packages are only needed if the distribution actually supports
# installing them.
if package_exists appmenu-gtk; then
  lib_list="$lib_list appmenu-gtk"
fi

# Waits for the user to press 'Y' or 'N'. Either uppercase of lowercase is
# accepted. Returns 0 for 'Y' and 1 for 'N'. If an optional parameter has
# been provided to yes_no(), the function also accepts RETURN as a user input.
# The parameter specifies the exit code that should be returned in that case.
# The function will echo the user's selection followed by a newline character.
# Users can abort the function by pressing CTRL-C. This will call "exit 1".
yes_no() {
  if [ 0 -ne "${do_default-0}" ] ; then
    [ $1 -eq 0 ] && echo "Y" || echo "N"
    return $1
  fi
  local c
  while :; do
    c="$(trap 'stty echo -iuclc icanon 2>/dev/null' EXIT INT TERM QUIT
         stty -echo iuclc -icanon 2>/dev/null
         dd count=1 bs=1 2>/dev/null | od -An -tx1)"
    case "$c" in
      " 0a") if [ -n "$1" ]; then
               [ $1 -eq 0 ] && echo "Y" || echo "N"
               return $1
             fi
             ;;
      " 79") echo "Y"
             return 0
             ;;
      " 6e") echo "N"
             return 1
             ;;
      "")    echo "Aborted" >&2
             exit 1
             ;;
      *)     # The user pressed an unrecognized key. As we are not echoing
             # any incorrect user input, alert the user by ringing the bell.
             (tput bel) 2>/dev/null
             ;;
    esac
  done
}

if test "$do_inst_syms" = "" && test 0 -eq ${do_quick_check-0}
then
  echo "This script installs all tools and libraries needed to build Chromium."
  echo ""
  echo "For most of the libraries, it can also install debugging symbols, which"
  echo "will allow you to debug code in the system libraries. Most developers"
  echo "won't need these symbols."
  echo -n "Do you want me to install them for you (y/N) "
  if yes_no 1; then
    do_inst_syms=1
  fi
fi
if test "$do_inst_syms" = "1"; then
  echo "Including debugging symbols."
else
  echo "Skipping debugging symbols."
  dbg_list=
fi

# When cross building for arm on 64-bit systems the host binaries
# that are part of v8 need to be compiled with -m32 which means
# that basic multilib support is needed.
if file /sbin/init | grep -q 'ELF 64-bit'; then
  arm_list="$arm_list g++-multilib"
fi

if test "$do_inst_arm" = "1" ; then
  echo "Including ARM cross toolchain."
else
  echo "Skipping ARM cross toolchain."
  arm_list=
fi

if test "$do_inst_nacl" = "1"; then
  echo "Including standalone NaCl dependencies."
else
  echo "Skipping standalone NaCl dependencies."
  nacl_list=
fi

packages="$(
  echo "${dev_list} ${lib_list} ${dbg_list} ${arm_list} ${nacl_list}" |
  tr " " "\n" | sort -u | tr "\n" " "
)"

if [ 1 -eq "${do_quick_check-0}" ] ; then
  failed_check="$(dpkg-query -W -f '${PackageSpec}:${Status}\n' \
    ${packages} 2>&1 | grep -v "ok installed" || :)"
  if [ -n "${failed_check}" ]; then
    echo
    nomatch="$(echo "${failed_check}" | \
      sed -e "s/^No packages found matching \(.*\).$/\1/;t;d")"
    missing="$(echo "${failed_check}" | \
      sed -e "/^No packages found matching/d;s/^\(.*\):.*$/\1/")"
    if [ "$nomatch" ]; then
      # Distinguish between packages that actually aren't available to the
      # system (i.e. not in any repo) and packages that just aren't known to
      # dpkg (i.e. managed by apt).
      unknown=""
      for p in ${nomatch}; do
        if apt-cache show ${p} > /dev/null 2>&1; then
          missing="${p}\n${missing}"
        else
          unknown="${p}\n${unknown}"
        fi
      done
      if [ -n "${unknown}" ]; then
        echo "WARNING: The following packages are unknown to your system"
        echo "(maybe missing a repo or need to 'sudo apt-get update'):"
        echo -e "${unknown}" | sed -e "s/^/  /"
      fi
    fi
    if [ -n "${missing}" ]; then
      echo "WARNING: The following packages are not installed:"
      echo -e "${missing}" | sed -e "s/^/  /"
    fi
    exit 1
  fi
  exit 0
fi

sudo apt-get update

# We initially run "apt-get" with the --reinstall option and parse its output.
# This way, we can find all the packages that need to be newly installed
# without accidentally promoting any packages from "auto" to "manual".
# We then re-run "apt-get" with just the list of missing packages.
echo "Finding missing packages..."
# Intentionally leaving $packages unquoted so it's more readable.
echo "Packages required: " $packages
echo
new_list_cmd="sudo apt-get install --reinstall $(echo $packages)"
if new_list="$(yes n | LANGUAGE=en LANG=C $new_list_cmd)"; then
  # We probably never hit this following line.
  echo "No missing packages, and the packages are up-to-date."
elif [ $? -eq 1 ]; then
  # We expect apt-get to have exit status of 1.
  # This indicates that we cancelled the install with "yes n|".
  new_list=$(echo "$new_list" |
    sed -e '1,/The following NEW packages will be installed:/d;s/^  //;t;d')
  new_list=$(echo "$new_list" | sed 's/ *$//')
  if [ -z "$new_list" ] ; then
    echo "No missing packages, and the packages are up-to-date."
  else
    echo "Installing missing packages: $new_list."
    sudo apt-get install ${do_quietly-} ${new_list}
  fi
  echo
else
  # An apt-get exit status of 100 indicates that a real error has occurred.

  # I am intentionally leaving out the '"'s around new_list_cmd,
  # as this makes it easier to cut and paste the output
  echo "The following command failed: " ${new_list_cmd}
  echo
  echo "It produces the following output:"
  yes n | $new_list_cmd || true
  echo
  echo "You will have to install the above packages yourself."
  echo
  exit 100
fi

# Install the Chrome OS default fonts. This must go after running
# apt-get, since install-chromeos-fonts depends on curl.
if test "$do_inst_chromeos_fonts" != "0"; then
  echo
  echo "Installing Chrome OS fonts."
  dir=`echo $0 | sed -r -e 's/\/[^/]+$//'`
  if ! sudo $dir/linux/install-chromeos-fonts.py; then
    echo "ERROR: The installation of the Chrome OS default fonts failed."
    if [ `stat -f -c %T $dir` == "nfs" ]; then
      echo "The reason is that your repo is installed on a remote file system."
    else
      echo "This is expected if your repo is installed on a remote file system."
    fi
    echo "It is recommended to install your repo on a local file system."
    echo "You can skip the installation of the Chrome OS default founts with"
    echo "the command line option: --no-chromeos-fonts."
    exit 1
  fi
else
  echo "Skipping installation of Chrome OS fonts."
fi

# Install 32bit backwards compatibility support for 64bit systems
if file /sbin/init | grep -q 'ELF 64-bit'; then
  if test "$do_inst_lib32" != "1"
  then
    echo "NOTE: If you were expecting the option to install 32bit libs,"
    echo "please run with the --lib32 flag."
    echo
    echo "Installation complete."
    exit 0
  else
    # This conditional statement has been added to deprecate and eventually
    # remove support for 32bit libraries on 64bit systems. But for the time
    # being, we still have to support a few legacy systems (e.g. bots), where
    # this feature is needed.
    # We only even give the user the option to install these libraries, if
    # they explicitly requested doing so by setting the --lib32 command line
    # flag.
    # And even then, we interactively ask them one more time whether they are
    # absolutely sure.
    # In order for that to work, we must reset the ${do_inst_lib32} variable.
    # There are other ways to achieve the same goal. But resetting the
    # variable is the best way to document the intended behavior -- and to
    # allow us to gradually deprecate and then remove the obsolete code.
    if test "${do_default-0}" -ne 1; then
      do_inst_lib32=
    fi
  fi

  echo "WARNING"
  echo
  echo "We no longer recommend that you use this script to install"
  echo "32bit libraries on a 64bit system. Instead, consider using the"
  echo "install-chroot.sh script to help you set up a 32bit environment"
  echo "for building and testing 32bit versions of Chrome."
  echo
  echo "The code for installing 32bit libraries on a 64bit system is"
  echo "unmaintained and might not work with modern versions of Ubuntu"
  echo "or Debian."
  if test "$do_inst_lib32" != "" ; then
    echo
    echo -n "Are you sure you want to proceed (y/N) "
    if yes_no 1; then
      do_inst_lib32=1
    fi
  fi
  if test "$do_inst_lib32" != "1"
  then
    exit 0
  fi

  # Standard 32bit compatibility libraries
  echo "First, installing the limited existing 32-bit support..."
  cmp_list="ia32-libs lib32asound2-dev lib32stdc++6 lib32z1
            lib32z1-dev libc6-dev-i386 libc6-i386 g++-multilib"
  if [ -n "`apt-cache search lib32readline-gplv2-dev 2>/dev/null`" ]; then
    cmp_list="${cmp_list} lib32readline-gplv2-dev"
  else
    cmp_list="${cmp_list} lib32readline5-dev"
  fi
  sudo apt-get install ${do_quietly-} $cmp_list

  tmp=/tmp/install-32bit.$$
  trap 'rm -rf "${tmp}"' EXIT INT TERM QUIT
  mkdir -p "${tmp}/apt/lists/partial" "${tmp}/cache" "${tmp}/partial"
  touch "${tmp}/status"

  [ -r /etc/apt/apt.conf ] && cp /etc/apt/apt.conf "${tmp}/apt/"
  cat >>"${tmp}/apt/apt.conf" <<EOF
        Apt::Architecture "i386";
        Dir::Cache "${tmp}/cache";
        Dir::Cache::Archives "${tmp}/";
        Dir::State::Lists "${tmp}/apt/lists/";
        Dir::State::status "${tmp}/status";
EOF

  # Download 32bit packages
  echo "Computing list of available 32bit packages..."
  sudo apt-get -c="${tmp}/apt/apt.conf" update

  echo "Downloading available 32bit packages..."
  sudo apt-get -c="${tmp}/apt/apt.conf" \
          --yes --download-only --force-yes --reinstall install \
          ${lib_list} ${dbg_list}

  # Open packages, remove everything that is not a library, move the
  # library to a lib32 directory and package everything as a *.deb file.
  echo "Repackaging and installing 32bit packages for use on 64bit systems..."
  for i in ${lib_list} ${dbg_list}; do
    orig="$(echo "${tmp}/${i}"_*_i386.deb)"
    compat="$(echo "${orig}" |
              sed -e 's,\(_[^_/]*_\)i386\(.deb\),-ia32\1amd64\2,')"
    rm -rf "${tmp}/staging"
    msg="$(fakeroot -u sh -exc '
      # Unpack 32bit Debian archive
      umask 022
      mkdir -p "'"${tmp}"'/staging/dpkg/DEBIAN"
      cd "'"${tmp}"'/staging"
      ar x "'${orig}'"
      tar Cfx dpkg data.tar*
      tar zCfx dpkg/DEBIAN control.tar.gz

      # Create a posix extended regular expression fragment that will
      # recognize the includes which have changed. Should be rare,
      # will almost always be empty.
      includes=`sed -n -e "s/^[0-9a-z]*  //g" \
                       -e "\,usr/include/,p" dpkg/DEBIAN/md5sums |
                  xargs -n 1 -I FILE /bin/sh -c \
                    "cmp -s dpkg/FILE /FILE || echo FILE" |
                  tr "\n" "|" |
                  sed -e "s,|$,,"`

      # If empty, set it to not match anything.
      test -z "$includes" && includes="^//"

      # Turn the conflicts into an extended RE for removal from the
      # Provides line.
      conflicts=`sed -n -e "/Conflicts/s/Conflicts: *//;T;s/, */|/g;p" \
                   dpkg/DEBIAN/control`

      # Rename package, change architecture, remove conflicts and dependencies
      sed -r -i                              \
          -e "/Package/s/$/-ia32/"           \
          -e "/Architecture/s/:.*$/: amd64/" \
          -e "/Depends/s/:.*/: ia32-libs/"   \
          -e "/Provides/s/($conflicts)(, *)?//g;T1;s/, *$//;:1"   \
          -e "/Recommends/d"                 \
          -e "/Conflicts/d"                  \
        dpkg/DEBIAN/control

      # Only keep files that live in "lib" directories or the includes
      # that have changed.
      sed -r -i                                                               \
          -e "/\/lib64\//d" -e "/\/.?bin\//d"                                 \
          -e "\,$includes,s,[ /]include/,&32/,g;s,include/32/,include32/,g"   \
          -e "s, lib/, lib32/,g"                                              \
          -e "s,/lib/,/lib32/,g"                                              \
          -e "t;d"                                                            \
          -e "\,^/usr/lib32/debug\(.*/lib32\),s,^/usr/lib32/debug,/usr/lib/debug," \
        dpkg/DEBIAN/md5sums

      # Re-run ldconfig after installation/removal
      { echo "#!/bin/sh"; echo "[ \"x\$1\" = xconfigure ]&&ldconfig||:"; } \
        >dpkg/DEBIAN/postinst
      { echo "#!/bin/sh"; echo "[ \"x\$1\" = xremove ]&&ldconfig||:"; } \
        >dpkg/DEBIAN/postrm
      chmod 755 dpkg/DEBIAN/postinst dpkg/DEBIAN/postrm

      # Remove any other control files
      find dpkg/DEBIAN -mindepth 1 "(" -name control -o -name md5sums -o \
                       -name postinst -o -name postrm ")" -o -print |
        xargs -r rm -rf

      # Remove any files/dirs that live outside of "lib" directories,
      # or are not in our list of changed includes.
      find dpkg -mindepth 1 -regextype posix-extended \
          "(" -name DEBIAN -o -name lib -o -regex "dpkg/($includes)" ")" \
          -prune -o -print | tac |
        xargs -r -n 1 sh -c "rm \$0 2>/dev/null || rmdir \$0 2>/dev/null || : "
      find dpkg -name lib64 -o -name bin -o -name "?bin" |
        tac | xargs -r rm -rf

      # Remove any symbolic links that were broken by the above steps.
      find -L dpkg -type l -print | tac | xargs -r rm -rf

      # Rename lib to lib32, but keep debug symbols in /usr/lib/debug/usr/lib32
      # That is where gdb looks for them.
      find dpkg -type d -o -path "*/lib/*" -print |
        xargs -r -n 1 sh -c "
          i=\$(echo \"\${0}\" |
               sed -e s,/lib/,/lib32/,g \
               -e s,/usr/lib32/debug\\\\\(.*/lib32\\\\\),/usr/lib/debug\\\\1,);
          mkdir -p \"\${i%/*}\";
          mv \"\${0}\" \"\${i}\""

      # Rename include to include32.
      [ -d "dpkg/usr/include" ] && mv "dpkg/usr/include" "dpkg/usr/include32"

      # Prune any empty directories
      find dpkg -type d | tac | xargs -r -n 1 rmdir 2>/dev/null || :

      # Create our own Debian package
      cd ..
      dpkg --build staging/dpkg .' 2>&1)"
    compat="$(eval echo $(echo "${compat}" |
                          sed -e 's,_[^_/]*_amd64.deb,_*_amd64.deb,'))"
    [ -r "${compat}" ] || {
      echo "${msg}" >&2
      echo "Failed to build new Debian archive!" >&2
      exit 1
    }

    msg="$(sudo dpkg -i "${compat}" 2>&1)" && {
        echo "Installed ${compat##*/}"
      } || {
        # echo "${msg}" >&2
        echo "Skipped ${compat##*/}"
      }
  done

  # Add symbolic links for developing 32bit code
  echo "Adding missing symbolic links, enabling 32bit code development..."
  for i in $(find /lib32 /usr/lib32 -maxdepth 1 -name \*.so.\* |
             sed -e 's/[.]so[.][0-9].*/.so/' |
             sort -u); do
    [ "x${i##*/}" = "xld-linux.so" ] && continue
    [ -r "$i" ] && continue
    j="$(ls "$i."* | sed -e 's/.*[.]so[.]\([^.]*\)$/\1/;t;d' |
         sort -n | tail -n 1)"
    [ -r "$i.$j" ] || continue
    sudo ln -s "${i##*/}.$j" "$i"
  done
fi
