Lots of tweaks to the install-chroot.sh and install-build-deps.sh

build/install-chroot.sh

 #!/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.
 
 # This script installs Debian-derived distributions in a chroot environment.
 # It can for example be used to have an accurate 32bit build and test
 # environment when otherwise working on a 64bit machine.
 # N. B. it is unlikely that this script will ever work on anything other than a
 # Debian-derived system.
 
+# Older Debian based systems had both "admin" and "adm" groups, with "admin"
+# apparently being used in more places. Newer distributions have standardized
+# on just the "adm" group. Check /etc/group for the prefered name of the
+# administrator group.
+admin=$(grep '^admin:' /etc/group >&/dev/null && echo admin || echo adm)

[Michael Moss, 2012/03/15 17:35:37]

nit: 'grep -q' (and maybe -s) is preferred elsewhere in this script, even though
the redirect is more portable.

[Markus (顧孟勤), 2012/03/15 18:20:10]

Fair enough. Normally, I tend to avoid -q and -s, as they are both unportable
and IMHO less readable than redirections. But I really don't feel particularly
strongly.

This code is by definition very specific to Linux; in fact, very specific to
Ubuntu/Debian. So, I don't think we really need to worry about portability as
much as we would worry in other scripts.

I found all occurrences of "grep" and switched them over to using -q and -s.

+
 usage() {
   echo "usage: ${0##*/} [-m mirror] [-g group,...] [-s] [-c]"
+  echo "-b dir       additional directories that should be bind mounted,"
+  echo '             or "NONE".'
+  echo "             Default: if local filesystems present, ask user for help"
   echo "-g group,... groups that can use the chroot unauthenticated"
-  echo "             Default: 'admin' and current user's group ('$(id -gn)')"
+  echo "             Default: '${admin}' and current user's group ('$(id -gn)')"
+  echo "-l           List all installed chroot environments"
   echo "-m mirror    an alternate repository mirror for package downloads"
   echo "-s           configure default deb-srcs"
   echo "-c           always copy 64bit helper binaries to 32bit chroot"
   echo "-h           this help message"
 }
 
 process_opts() {
   local OPTNAME OPTIND OPTERR OPTARG
-  while getopts ":g:m:sch" OPTNAME; do
+  while getopts ":b:g:lm:sch" OPTNAME; do
     case "$OPTNAME" in
+      b)
+        if [ "${OPTARG}" = "NONE" -a -z "${bind_mounts}" ]; then
+          bind_mounts="${OPTARG}"
+        else
+          if [ "${bind_mounts}" = "NONE" -o "${OPTARG}" = "${OPTARG#/}" -o \
+               ! -d "${OPTARG}" ]; then
+            echo "Invalid -l option(s)"

[Michael Moss, 2012/03/15 17:35:37]

typo: Invalid -b option(s)

[Markus (顧孟勤), 2012/03/15 18:20:10]

Thanks!

+            usage
+            exit 1
+          fi
+          bind_mounts="${bind_mounts}
+${OPTARG} ${OPTARG} none rw,bind 0 0"
+        fi
+        ;;
       g)
         [ -n "${OPTARG}" ] &&
           chroot_groups="${chroot_groups}${chroot_groups:+,}${OPTARG}"
         ;;
+      l)
+        list_all_chroots
+        exit
+        ;;
       m)
         if [ -n "${mirror}" ]; then
           echo "You can only specify exactly one mirror location"
           usage
           exit 1
         fi
         mirror="$OPTARG"
         ;;
       s)
         add_srcs="y"
@@ skipping 18 matching lines @@
     esac
   done
 
   if [ $# -ge ${OPTIND} ]; then
     eval echo "Unexpected command line argument: \${${OPTIND}}"
     usage
     exit 1
   fi
 }
 
+list_all_chroots() {
+  for i in /var/lib/chroot/*; do
+    i="${i##*/}"
+    [ "${i}" = "*" ] && continue
+    [ -x "/usr/local/bin/${i%bit}" ] || continue
+    grep "^\[${i%bit}\]\$" /etc/schroot/schroot.conf >&/dev/null || continue

[Michael Moss, 2012/03/15 17:35:37]

nit: same thing with the -q

+    [ -r "/etc/schroot/script-${i}" -a \
+      -r "/etc/schroot/mount-${i}" ] || continue
+    echo "${i%bit}"
+  done
+}
+
+getkey() {
+  (
+    trap 'stty echo -iuclc icanon 2>/dev/null' EXIT INT TERM QUIT HUP
+    stty -echo iuclc -icanon 2>/dev/null
+    dd count=1 bs=1 2>/dev/null
+  )
+}
+
+chr() {
+  printf "\\$(printf '%03o' "$1")"
+}
+
+ord() {
+  printf '%d' $(printf '%c' "$1" | od -tu1 -An)
+}
+
+is_network_drive() {
+  stat -c %T -f "$1/" 2>/dev/null |
+    egrep '^nfs|cifs|smbfs' >&/dev/null
+}
 
 # Check that we are running as a regular user
 [ "$(id -nu)" = root ] && {
   echo "Run this script as a regular user and provide your \"sudo\""           \
        "password if requested" >&2
   exit 1
 }
-mkdir -p "$HOME/chroot/"
 
 process_opts "$@"
 
+echo "This script will help you through the process of installing a"
+echo "Debian or Ubuntu distribution in a chroot environment. You will"
+echo "have to provide your \"sudo\" password when requested."
+echo
+
 # Error handler
-trap 'exit 1' INT TERM QUIT
+trap 'exit 1' INT TERM QUIT HUP
 trap 'sudo apt-get clean; tput bel; echo; echo Failed' EXIT
 
 # Install any missing applications that this script relies on. If these packages
 # are already installed, don't force another "apt-get install". That would
 # prevent them from being auto-removed, if they ever become eligible for that.
 # And as this script only needs the packages once, there is no good reason to
 # introduce a hard dependency on things such as dchroot and debootstrap.
 dep=
-for i in dchroot debootstrap; do
+for i in dchroot debootstrap libwww-perl; do
   [ -d /usr/share/doc/"$i" ] || dep="$dep $i"
 done
 [ -n "$dep" ] && sudo apt-get -y install $dep
 sudo apt-get -y install schroot
 
 # Create directory for chroot
 sudo mkdir -p /var/lib/chroot
 
 # Find chroot environments that can be installed with debootstrap
 targets="$(cd /usr/share/debootstrap/scripts
            ls | grep '^[a-z]*$')"
 
 # Ask user to pick one of the available targets
 echo "The following targets are available to be installed in a chroot:"
 j=1; for i in $targets; do
   printf '%4d: %s\n' "$j" "$i"
   j=$(($j+1))
 done
 while :; do
   printf "Which target would you like to install: "
   read n
   [ "$n" -gt 0 -a "$n" -lt "$j" ] >&/dev/null && break
 done
 j=1; for i in $targets; do
   [ "$j" -eq "$n" ] && { distname="$i"; break; }
   j=$(($j+1))
 done
+echo
 
 # On x86-64, ask whether the user wants to install x86-32 or x86-64
 archflag=
 arch=
 if [ "$(uname -m)" = x86_64 ]; then
   while :; do
     echo "You are running a 64bit kernel. This allows you to install either a"
     printf "32bit or a 64bit chroot environment. %s"                           \
            "Which one do you want (32, 64) "
     read arch
     [ "${arch}" == 32 -o "${arch}" == 64 ] && break
   done
   [ "${arch}" == 32 ] && archflag="--arch i386" || archflag="--arch amd64"
   arch="${arch}bit"
+  echo
 fi
 target="${distname}${arch}"
 
-# Don't overwrite an existing installation
+# Don't accidentally overwrite an existing installation
 [ -d /var/lib/chroot/"${target}" ] && {
-  echo "This chroot already exists on your machine." >&2
-  echo "Delete /var/lib/chroot/${target} if you want to start over." >&2
-  exit 1
+  while :; do
+    echo "This chroot already exists on your machine."
+    if schroot -l --all-sessions 2>&1 |
+       sed 's/^session://' |
+       grep "^${target%bit}-" >&/dev/null; then
+      echo "And it appears to be in active use. Terminate all programs that"
+      echo "are currently using the chroot environment and then re-run this"
+      echo "script."
+      echo "If you still get an error message, you might have stale mounts"
+      echo "that you forgot to delete. You can always clean up mounts by"
+      echo "executing \"${target%bit} -c\"."
+      exit 1
+    fi
+    echo "I can abort installation, I can overwrite the existing chroot,"
+    echo "or I can delete the old one and then exit. What would you like to"
+    printf "do (a/o/d)? "
+    read choice
+    case "${choice}" in
+      a|A) exit 1;;
+      o|O) sudo rm -rf "/var/lib/chroot/${target}"; break;;
+      d|D) sudo rm -rf "/var/lib/chroot/${target}"; exit 0;;
+    esac
+  done
+  echo
 }
 sudo mkdir -p /var/lib/chroot/"${target}"
 
 # Offer to include additional standard repositories for Ubuntu-based chroots.
 alt_repos=
 grep ubuntu.com /usr/share/debootstrap/scripts/"${distname}" >&/dev/null && {
   while :; do
     echo "Would you like to add ${distname}-updates and ${distname}-security "
-    echo -n "to the chroot's sources.list (y/n)? "
+    printf "to the chroot's sources.list (y/n)? "
     read alt_repos
     case "${alt_repos}" in
       y|Y)
         alt_repos="y"
         break
       ;;
       n|N)
         break
       ;;
     esac
   done
+  echo
 }
 
+# Check for non-standard file system mount points and ask the user whether
+# they should be imported into the chroot environment
+if [ -z "${bind_mounts}" ]; then
+  mounts="$(awk '$2 != "/" && $2 !~ "^/boot" && $2 !~ "^/home" &&
+                 $2 !~ "^/media" && $2 !~ "^/run" &&
+                 ($3 ~ "ext[2-4]" || $3 == "reiserfs" || $3 == "btrfs" ||
+                 $3 == "xfs" || $3 == "jfs" || $3 == "u?msdos" ||
+                 $3 == "v?fat" || $3 == "hfs" || $3 == "ntfs" ||
+                 $3 ~ "nfs[4-9]?" || $3 == "smbfs" || $3 == "cifs") {
+                   print $2
+                 }' /proc/mounts |
+            head -n26)"

[Michael Moss, 2012/03/15 17:35:37]

Maybe add to the comment above that we limit it to 26 for convenience of
"lettering" the choices below. It took a minute to figure out why you were
trying to give me DOS limitation flashbacks.

[Markus (顧孟勤), 2012/03/15 18:20:10]

Done

+  if [ -n "${mounts}" ]; then
+    echo "You appear to have non-standard mount points that you"
+    echo "might want to import into the chroot environment:"
+    echo
+    sel=
+    while :; do
+      # Print a menu, listing all non-default mounts of local or network
+      # file systems.
+      j=1; for m in ${mounts}; do
+        c="$(printf $(printf '\\%03o' $((64+$j))))"
+        echo "$sel" | grep $c >/dev/null &&
+          state="mounted in chroot" || state="$(tput el)"
+        printf "   $c) %-40s${state}\n" "$m"
+        j=$(($j+1))
+      done
+      # Allow user to interactively (de-)select any of the entries
+      echo
+      printf "Select mount points that you want to be included or press %s" \
+             "SPACE to continue"
+      c="$(getkey | tr a-z A-Z)"
+      [ "$c" == " " ] && { echo; echo; break; }
+      if [ -z "$c" ] ||
+         [ "$c" '<' 'A' -o $(ord "$c") -gt $((64 + $(ord "$j"))) ]; then
+          # Invalid input, ring the console bell
+          tput bel
+      else
+        # Toggle the selection for the given entry
+        if echo "$sel" | grep $c >/dev/null; then
+          sel="$(printf "$sel" | sed "s/$c//")"
+        else
+          sel="$sel$c"
+        fi
+      fi
+      # Reposition cursor to the top of the list of entries
+      tput cuu $(($j + 1))
+      echo
+    done
+  fi
+  j=1; for m in ${mounts}; do
+    c="$(chr $(($j + 64)))"
+    if echo "$sel" | grep $c >/dev/null; then
+      bind_mounts="${bind_mounts}$m $m none rw,bind 0 0
+"
+    fi
+    j=$(($j+1))
+  done
+fi
+
 # Remove stale entry from /etc/schroot/schroot.conf. Entries start
 # with the target name in square brackets, followed by an arbitrary
 # number of lines. The entry stops when either the end of file has
 # been reached, or when the beginning of a new target is encountered.
 # This means, we cannot easily match for a range of lines in
 # "sed". Instead, we actually have to iterate over each line and check
 # whether it is the beginning of a new entry.
 sudo sed -ni '/^[[]'"${target%bit}"']$/,${:1;n;/^[[]/b2;b1;:2;p;n;b2};p'       \
          /etc/schroot/schroot.conf
 
 # Download base system. This takes some time
 if [ -z "${mirror}" ]; then
  grep ubuntu.com /usr/share/debootstrap/scripts/"${distname}" >&/dev/null &&
    mirror="http://archive.ubuntu.com/ubuntu" ||
    mirror="http://ftp.us.debian.org/debian"
 fi
  sudo debootstrap ${archflag} "${distname}" /var/lib/chroot/"${target}"        \
                   "$mirror"
 
 # Add new entry to /etc/schroot/schroot.conf
 grep ubuntu.com /usr/share/debootstrap/scripts/"${distname}" >&/dev/null &&
   brand="Ubuntu" || brand="Debian"
 if [ -z "${chroot_groups}" ]; then
-  chroot_groups="admin,$(id -gn)"
+  chroot_groups="${admin},$(id -gn)"
 fi
+# Older versions of schroot wanted a "priority=" line, whereas recent
+# versions deprecate "priority=" and warn if they see it. We don't have
+# a good feature test, but scanning for the string "priority=" in the
+# existing "schroot.conf" file is a good indication of what to do.
+priority=$(grep 'priority=' /etc/schroot/schroot.conf >&/dev/null &&
+           echo 'priority=3' || :)
 sudo sh -c 'cat >>/etc/schroot/schroot.conf' <<EOF
 [${target%bit}]
 description=${brand} ${distname} ${arch}
 type=directory
 directory=/var/lib/chroot/${target}
-priority=3
 users=root
 groups=${chroot_groups}
 root-groups=${chroot_groups}
 personality=linux$([ "${arch}" != 64bit ] && echo 32)
 script-config=script-${target}
+${priority}
 
 EOF
 
-# Set up a special directory that changes contents depending on the target
-# that is executing.
-sed '/^FSTAB=/s,/mount-defaults",/mount-'"${target}"'",'                       \
+# Set up a list of mount points that is specific to this
+# chroot environment.
+sed '/^FSTAB=/s,"[^"]*","/etc/schroot/mount-'"${target}"'",' \
          /etc/schroot/script-defaults |
   sudo sh -c 'cat >/etc/schroot/script-'"${target}"
 sed '\,^/home[/[:space:]],s/\([,[:space:]]\)bind[[:space:]]/\1rbind /' \
   /etc/schroot/mount-defaults |
   sudo sh -c 'cat > /etc/schroot/mount-'"${target}"
-echo "$HOME/chroot/.${target} $HOME/chroot none rw,bind 0 0" |
+
+# Add the extra mount points that the user told us about
+[ -n "${bind_mounts}" -a "${bind_mounts}" != "NONE" ] &&
+  printf "${bind_mounts}" |
+    sudo sh -c 'cat >>/etc/schroot/mount-'"${target}"
+
+# If this system has a "/media" mountpoint, import it into the chroot
+# environment. Most modern distributions use this mount point to
+# automatically mount devices such as CDROMs, USB sticks, etc...
+if [ -d /media ] &&
+   ! grep '^/media' /etc/schroot/mount-"${target}" >&/dev/null; then
+  echo '/media /media none rw,bind 0 0' |

[Michael Moss, 2012/03/15 17:35:37]

This should probably be rbind, since these things are mounted in dirs under
/media. Just binding /media won't make the submounts available.

[Markus (顧孟勤), 2012/03/15 18:20:10]

Very good call :-) Yes, that would never have worked as intended.

+    sudo sh -c 'cat >>/etc/schroot/mount-'"${target}"
+fi
+
+# Share /dev/shm and possibly /run/shm
+grep '^/dev/shm' /etc/schroot/mount-"${target}" >&/dev/null ||
+  echo '/dev/shm /dev/shm none rw,bind 0 0' |
+    sudo sh -c 'cat >>/etc/schroot/mount-'"${target}"
+if [ -d "/var/lib/chroot/${target}/run" ] &&
+   ! grep '^/run/shm' /etc/schroot/mount-"${target}" >&/dev/null; then
+  { [ -d /run ] && echo '/run/shm /run/shm none rw,bind 0 0' ||
+                   echo '/dev/shm /run/shm none rw,bind 0 0'; } |
+    sudo sh -c 'cat >>/etc/schroot/mount-'"${target}"
+fi
+
+# Set up a special directory that changes contents depending on the target
+# that is executing.
+d="$(readlink -f "${HOME}/chroot" 2>/dev/null || echo "${HOME}/chroot")"
+s="${d}/.${target}"
+echo "${s} ${d} none rw,bind 0 0" |
   sudo sh -c 'cat >>/etc/schroot/mount-'"${target}"
-mkdir -p "$HOME/chroot/.${target}"
+mkdir -p "${s}"
 
 # Install a helper script to launch commands in the chroot
-sudo sh -c 'cat >/usr/local/bin/'"${target%bit}" <<EOF
+sudo sh -c 'cat >/usr/local/bin/'"${target%bit}" <<'EOF'
 #!/bin/bash
-if [ \$# -eq 0 ]; then
-  exec schroot -c ${target%bit} -p
+
+chroot="${0##*/}"
+
+wrap() {
+  # Word-wrap the text passed-in on stdin. Optionally, on continuation lines
+  # insert the same number of spaces as the number of characters in the
+  # parameter(s) passed to this function.
+  # If the "fold" program cannot be found, or if the actual width of the
+  # terminal cannot be determined, this function doesn't attempt to do any
+  # wrapping.
+  local f="$(type -P fold)"
+  [ -z "${f}" ] && { cat; return; }
+  local c="$(stty -a </dev/tty 2>/dev/null |
+             sed 's/.*columns[[:space:]]*\([0-9]*\).*/\1/;t;d')"
+  [ -z "${c}" ] && { cat; return; }
+  local i="$(echo "$*"|sed 's/./ /g')"
+  local j="$(printf %s "${i}"|wc -c)"
+  if [ "${c}" -gt "${j}" ]; then
+    dd bs=1 count="${j}" 2>/dev/null
+    "${f}" -sw "$((${c}-${j}))" | sed '2,$s/^/'"${i}"'/'
+  else
+    "${f}" -sw "${c}"
+  fi
+}
+
+help() {
+  echo "Usage ${0##*/} [-h|--help] [-c|--clean] [-C|--clean-all] [-l|--list] [--] args" | wrap "Usage ${0##*/} "
+  echo "  help:      print this message"                                                | wrap "             "
+  echo "  list:      list all known chroot environments"                                | wrap "             "
+  echo "  clean:     remove all old chroot sessions for \"${chroot}\""                  | wrap "             "
+  echo "  clean-all: remove all old chroot sessions for all environments"               | wrap "             "
+  exit 0
+}
+
+clean() {
+  local s t rc
+  rc=0
+  for s in $(schroot -l --all-sessions); do
+    if [ -n "$1" ]; then
+      t="${s#session:}"
+      [ "${t#${chroot}-}" == "${t}" ] && continue
+    fi
+    if ls -l /proc/*/{cwd,fd} 2>/dev/null |
+       fgrep -q "/var/lib/schroot/mount/${t}"; then
+      echo "Session \"${t}\" still has active users, not cleaning up" | wrap
+      rc=1
+      continue
+    fi
+    schroot -c "${s}" -e || rc=1
+  done
+  exit ${rc}
+}
+
+list() {
+  for e in $(schroot -l); do
+    e="${e#chroot:}"
+    [ -x "/usr/local/bin/${e}" ] || continue
+    if schroot -l --all-sessions 2>/dev/null |
+       sed 's/^session://' |
+       grep "^${e}-" >&/dev/null; then
+      echo "${e} is currently active"
+    else
+      echo "${e}"
+    fi
+  done
+  exit 0
+}
+
+while [ "$#" -ne 0 ]; do
+  case "$1" in
+    --)             shift; break;;
+    -h|--help)      shift; help;;
+    -l|--list)      shift; list;;
+    -c|--clean)     shift; clean "${chroot}";;
+    -C|--clean-all) shift; clean;;
+    *)              break;;
+  esac
+done
+
+session="$(schroot -c "${chroot}" -b)"
+
+if [ $# -eq 0 ]; then
+  schroot -c "${session}" -r -p
 else
-  p="\$1"; shift
-  exec schroot -c ${target%bit} -p "\$p" -- "\$@"
+  p="$1"; shift
+  schroot -c "${session}" -r -p "$p" -- "$@"
 fi
-exit 1
+rc=$?
+
+i=$(schroot -c "${session}" -r -p ls -- -id /proc/self/root/. |
+     awk '{ print $1 }') 2>/dev/null
+while [ -n "$i" ]; do
+  pids=$(ls -id1 /proc/*/root/. 2>/dev/null |
+         sed -e 's,^[^0-9]*'$i'.*/\([1-9][0-9]*\)/.*$,\1,
+                 t
+                 d') >/dev/null 2>&1
+  [ -z "$pids" ] && break
+  kill -9 $pids
+done
+schroot -c "${session}" -e
+exit $rc
 EOF
 sudo chown root:root /usr/local/bin/"${target%bit}"
 sudo chmod 755 /usr/local/bin/"${target%bit}"
 
 # Add the standard Ubuntu update repositories if requested.
 [ "${alt_repos}" = "y" -a \
   -r "/var/lib/chroot/${target}/etc/apt/sources.list" ] &&
 sudo sed -i '/^deb .* [^ -]\+ main$/p
              s/^\(deb .* [^ -]\+\) main/\1-security main/
              p
              t1
              d
              :1;s/-security main/-updates main/
              t
              d' "/var/lib/chroot/${target}/etc/apt/sources.list"
 
 # Add a few more repositories to the chroot
+[ -r "/var/lib/chroot/${target}/etc/apt/sources.list" ] &&
+sudo sed -i 's/ main$/ main restricted universe multiverse/' \
+         "/var/lib/chroot/${target}/etc/apt/sources.list"
+
+# Add the Ubuntu "partner" repository, if available
+if [ -r "/var/lib/chroot/${target}/etc/apt/sources.list" ] &&
+   HEAD "http://archive.canonical.com/ubuntu/dists/${distname}/partner" \
+   >&/dev/null; then
+  sudo sh -c '
+    echo "deb http://archive.canonical.com/ubuntu" \
+         "'"${distname}"' partner" \
+      >>"/var/lib/chroot/'"${target}"'/etc/apt/sources.list"'
+fi
+
+# Add source repositories, if the user requested we do so
 [ "${add_srcs}" = "y" -a \
   -r "/var/lib/chroot/${target}/etc/apt/sources.list" ] &&
-sudo sed -i 's/ main$/ main restricted universe multiverse/
-             p
-             t1
-             d
-          :1;s/^deb/deb-src/
-             t
-             d' "/var/lib/chroot/${target}/etc/apt/sources.list"
+sudo sed -i '/^deb[^-]/p
+             s/^deb\([^-]\)/deb-src\1/' \
+         "/var/lib/chroot/${target}/etc/apt/sources.list"
 
 # Update packages
-sudo schroot -c "${target%bit}" -p -- /bin/sh -c '
+sudo "/usr/local/bin/${target%bit}" /bin/sh -c '
   apt-get update; apt-get -y dist-upgrade' || :
 
 # Install a couple of missing packages
 for i in debian-keyring ubuntu-keyring locales sudo; do
   [ -d "/var/lib/chroot/${target}/usr/share/doc/$i" ] ||
-    sudo schroot -c "${target%bit}" -p -- apt-get -y install "$i" || :
+    sudo "/usr/local/bin/${target%bit}" apt-get -y install "$i" || :
 done
 
 # Configure locales
-sudo schroot -c "${target%bit}" -p -- /bin/sh -c '
+sudo "/usr/local/bin/${target%bit}" /bin/sh -c '
   l='"${LANG:-en_US}"'; l="${l%%.*}"
   [ -r /etc/locale.gen ] &&
     sed -i "s/^# \($l\)/\1/" /etc/locale.gen
   locale-gen $LANG en_US en_US.UTF-8' || :
 
+# Enable multi-arch support, if available
+sudo "/usr/local/bin/${target%bit}" dpkg --assert-multi-arch >&/dev/null &&
+  [ -r "/var/lib/chroot/${target}/etc/apt/sources.list" ] && {
+  sudo sed -i 's/ / [arch=amd64,i386] /' \
+              "/var/lib/chroot/${target}/etc/apt/sources.list"
+  [ -d /var/lib/chroot/${target}/etc/dpkg/dpkg.cfg.d/ ] &&
+  echo foreign-architecture \
+       $([ "${arch}" = "32bit" ] && echo amd64 || echo i386) |
+    sudo sh -c "cat >'/var/lib/chroot/${target}/etc/dpkg/dpkg.cfg.d/multiarch'"
+}
+
 # Configure "sudo" package
-sudo schroot -c "${target%bit}" -p -- /bin/sh -c '
+sudo "/usr/local/bin/${target%bit}" /bin/sh -c '
   egrep '"'^$(id -nu) '"' /etc/sudoers >/dev/null 2>&1 ||
   echo '"'$(id -nu) ALL=(ALL) ALL'"' >>/etc/sudoers'
 
 # Install a few more commonly used packages
-sudo schroot -c "${target%bit}" -p -- apt-get -y install                       \
+sudo "/usr/local/bin/${target%bit}" apt-get -y install                         \
   autoconf automake1.9 dpkg-dev g++-multilib gcc-multilib gdb less libtool     \
   strace
 
 # If running a 32bit environment on a 64bit machine, install a few binaries
 # as 64bit. This is only done automatically if the chroot distro is the same as
 # the host, otherwise there might be incompatibilities in build settings or
 # runtime dependencies. The user can force it with the '-c' flag.
 host_distro=$(grep DISTRIB_CODENAME /etc/lsb-release 2>/dev/null | \
   cut -d "=" -f 2)
 if [ "${copy_64}" = "y" -o \
     "${host_distro}" = "${distname}" -a "${arch}" = 32bit ] && \
     file /bin/bash 2>/dev/null | grep -q x86-64; then
-  readlinepkg=$(sudo schroot -c "${target%bit}" -p -- sh -c \
+  readlinepkg=$(sudo "/usr/local/bin/${target%bit}" sh -c \
     'apt-cache search "lib64readline.\$" | sort | tail -n 1 | cut -d " " -f 1')
-  sudo schroot -c "${target%bit}" -p -- apt-get -y install                     \
+  sudo "/usr/local/bin/${target%bit}" apt-get -y install                       \
     lib64expat1 lib64ncurses5 ${readlinepkg} lib64z1
   dep=
-  for i in binutils gdb strace; do
+  for i in binutils gdb; do
     [ -d /usr/share/doc/"$i" ] || dep="$dep $i"
   done
   [ -n "$dep" ] && sudo apt-get -y install $dep
-  sudo cp /usr/bin/gdb "/var/lib/chroot/${target}/usr/local/bin/"
-  sudo cp /usr/bin/ld "/var/lib/chroot/${target}/usr/local/bin/"
+  sudo mkdir -p "/var/lib/chroot/${target}/usr/local/lib/amd64"
   for i in libbfd libpython; do
     lib="$({ ldd /usr/bin/ld; ldd /usr/bin/gdb; } |
            grep "$i" | awk '{ print $3 }')"
     if [ -n "$lib" -a -r "$lib" ]; then
-      sudo cp "$lib" "/var/lib/chroot/${target}/usr/lib64/"
+      sudo cp "$lib" "/var/lib/chroot/${target}/usr/local/lib/amd64"
     fi
   done
   for lib in libssl libcrypt; do
-    sudo cp /usr/lib/$lib* "/var/lib/chroot/${target}/usr/lib64/" || :
+    for path in /usr/lib /usr/lib/x86_64-linux-gnu; do
+      sudo cp $path/$lib* \
+              "/var/lib/chroot/${target}/usr/local/lib/amd64/" >&/dev/null || :
+    done
+  done
+  for i in gdb ld; do
+    sudo cp /usr/bin/$i "/var/lib/chroot/${target}/usr/local/lib/amd64/"
+    sudo sh -c "cat >'/var/lib/chroot/${target}/usr/local/bin/$i'" <<EOF
+#!/bin/sh
+exec /lib64/ld-linux-x86-64.so.2 --library-path /usr/local/lib/amd64 \
+  /usr/local/lib/amd64/$i "\$@"
+EOF
+    sudo chmod 755 "/var/lib/chroot/${target}/usr/local/bin/$i"
+  done
+fi
+
+
+# If the install-build-deps.sh script can be found, offer to run it now
+script="$(dirname $(readlink -f "$0"))/install-build-deps.sh"
+if [ -x "${script}" ]; then
+  while :; do
+    echo
+    echo "If you plan on building Chrome inside of the new chroot environment,"
+    echo "you now have to install the build dependencies. Do you want me to"
+    printf "start the script that does this for you (y/n)? "
+    read install_deps
+    case "${install_deps}" in
+      y|Y)
+        echo
+        # We prefer running the script in-place, but this might not be
+        # possible, if it lives on a network filesystem that denies
+        # access to root.
+        tmp_script=
+        if ! sudo "${target%bit}" sh -c "[ -x '${script}' ]" >&/dev/null; then
+          tmp_script="/tmp/${script##*/}"
+          cp "${script}" "${tmp_script}"
+        fi
+        # Some distributions automatically start an instance of the system-
+        # wide dbus daemon, when installing the Chrome build depencies. This
+        # prevents the chroot session from being closed. So, we always try
+        # to shut down any running instance of dbus.
+        sudo "${target%bit}" sh -c "${script} --no-lib32;
+              rc=$?;
+              /etc/init.d/dbus stop >/dev/null 2>&1 || :;
+              exit $rc"
+        rc=$?
+        [ -n "${tmp_script}" ] && rm -f "${tmp_script}"
+        [ $rc -ne 0 ] && exit $rc
+        break
+      ;;
+      n|N)
+        break
+      ;;
+    esac
+  done
+  echo
+fi
+
+# Check whether ~/chroot is on a (slow) network file system and offer to
+# relocate it. Also offer relocation, if the user appears to have multiple
+# spindles (as indicated by "${bind_mount}" being non-empty).
+# We only offer this option, if it doesn't look as if a chroot environment
+# is currently active. Otherwise, relocation is unlikely to work and it
+# can be difficult for the user to recover from the failed attempt to relocate
+# the ~/chroot directory.
+# We don't aim to solve this problem for every configuration,
+# but try to help with the common cases. For more advanced configuration
+# options, the user can always manually adjust things.
+mkdir -p "${HOME}/chroot/"
+if [ ! -h "${HOME}/chroot" ] &&
+   ! egrep '^[^[:space:]]*/chroot' /etc/fstab >&/dev/null &&
+   { [ -n "${bind_mounts}" -a "${bind_mounts}" != "NONE" ] ||
+     is_network_drive "${HOME}/chroot"; } &&
+   ! egrep '/var/lib/[^/]*chroot/.*/chroot' /proc/mounts >&/dev/null; then
+  echo "${HOME}/chroot is currently located on the same device as your"
+  echo "home directory."
+  echo "This might not be what you want. Do you want me to move it somewhere"
+  echo "else?"
+  # If the computer has multiple spindles, many users configure all or part of
+  # the secondary hard disk to be writable by the primary user of this machine.
+  # Make some reasonable effort to detect this type of configuration and
+  # then offer a good location for where to put the ~/chroot directory.
+  suggest=
+  for i in $(echo "${bind_mounts}"|cut -d ' ' -f 1); do
+    if [ -d "$i" -a -w "$i" -a \( ! -a "$i/chroot" -o -w "$i/chroot/." \) ] &&
+       ! is_network_drive "$i"; then
+      suggest="$i"
+    else
+      for j in "$i/"*; do
+        if [ -d "$j" -a -w "$j" -a \
+             \( ! -a "$j/chroot" -o -w "$j/chroot/." \) ] &&
+           ! is_network_drive "$j"; then
+          suggest="$j"
+        else
+          for k in "$j/"*; do
+            if [ -d "$k" -a -w "$k" -a \
+                 \( ! -a "$k/chroot" -o -w "$k/chroot/." \) ] &&
+               ! is_network_drive "$k"; then
+              suggest="$k"
+              break
+            fi
+          done
+        fi
+        [ -n "${suggest}" ] && break
+      done
+    fi
+    [ -n "${suggest}" ] && break
+  done
+  def_suggest="${HOME}"
+  if [ -n "${suggest}" ]; then
+    # For home directories that reside on network drives, make our suggestion
+    # the default option. For home directories that reside on a local drive,
+    # require that the user manually enters the new location.
+    if is_network_drive "${HOME}"; then
+      def_suggest="${suggest}"
+    else
+      echo "A good location would probably be in \"${suggest}\""
+    fi
+  fi
+  while :; do
+    printf "Physical location [${def_suggest}]: "
+    read dir
+    [ -z "${dir}" ] && dir="${def_suggest}"
+    [ "${dir%%/}" == "${HOME%%/}" ] && break
+    if ! [ -d "${dir}" -a -w "${dir}" ] ||
+       [ -a "${dir}/chroot" -a ! -w "${dir}/chroot/." ]; then
+      echo "Cannot write to ${dir}/chroot. Please try again"
+    else
+      mv "${HOME}/chroot" "${dir}/chroot"
+      ln -s "${dir}/chroot" "${HOME}/chroot"
+      for i in $(list_all_chroots); do
+        sudo "$i" mkdir -p "${dir}/chroot"
+      done
+      sudo sed -i "s,${HOME}/chroot,${dir}/chroot,g" /etc/schroot/mount-*
+      break
+    fi
   done
 fi
 
 # Clean up package files
 sudo schroot -c "${target%bit}" -p -- apt-get clean
 sudo apt-get clean
 
+trap '' INT TERM QUIT HUP
+trap '' EXIT
+
 # Let the user know what we did
-trap '' INT TERM QUIT
-trap '' EXIT
 cat <<EOF
 
 
 Successfully installed ${distname} ${arch}
 
 You can run programs inside of the chroot by invoking the "${target%bit}"
 command.
 
-Your home directory is shared between the host and the chroot. But I configured
-$HOME/chroot to be private to the chroot environment. You can use it
-for files that need to differ between environments.
+This command can be used with arguments, in order to just run a single
+program inside of the chroot environment (e.g. "${target%bit} make chrome")
+or without arguments, in order to run an interactive shell session inside
+of the chroot environment.
+
+If you need to run things as "root", you can use "sudo" (e.g. try
+"sudo ${target%bit} apt-get update").
+
+Your home directory is shared between the host and the chroot. But I
+configured "${HOME}/chroot" to be private to the chroot environment.
+You can use it for files that need to differ between environments. This
+would be a good place to store binaries that you have built from your
+source files.
+
+For Chrome, this probably means you want to make your "out" directory a
+symbolic link that points somewhere inside of "${HOME}/chroot".
+
+You still need to run "gclient runhooks" whenever you switch from building
+outside of the chroot to inside of the chroot. But you will find that you
+don't have to repeatedly erase and then completely rebuild all your object
+and binary files.
+
 EOF