Build: Extract debian control files to sysroots

build/linux/sysroot_scripts/sysroot-creator.sh

 # Copyright 2014 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 should not be run directly but sourced by the other
 # scripts (e.g. sysroot-creator-trusty.sh).  Its up to the parent scripts
 # to define certain environment variables: e.g.
 #  DISTRO=ubuntu
 #  DIST=trusty
 #  APT_REPO=http://archive.ubuntu.com/ubuntu
@@ skipping 357 matching lines @@
   mkdir -p ${INSTALL_ROOT}/usr/lib/pkgconfig
   mv ${INSTALL_ROOT}/usr/lib/mipsel-linux-gnu/pkgconfig/* \
       ${INSTALL_ROOT}/usr/lib/pkgconfig
 }
 
 
 InstallIntoSysroot() {
   Banner "Install Libs And Headers Into Jail"
 
   mkdir -p ${BUILD_DIR}/debian-packages
-  mkdir -p ${INSTALL_ROOT}
+  mkdir -p ${INSTALL_ROOT}/debian
+  touch ${INSTALL_ROOT}/debian/control

[Sam Clegg, 2016/10/11 03:06:46]

Why make an empty control file here?

[Tom (Use chromium acct), 2016/10/11 05:33:55]

you need it to run dpkg-shlibdeps

[Lei Zhang, 2016/10/12 01:15:47]

Maybe just add a brief comment to explain why it exists.

[Tom (Use chromium acct), 2016/10/12 01:23:48]

Done.

   while (( "$#" )); do
     local file="$1"
     local package="${BUILD_DIR}/debian-packages/${file##*/}"
     shift
     local sha256sum="$1"
     shift
     if [ "${#sha256sum}" -ne "64" ]; then
       echo "Bad sha256sum from package list"
       exit 1
     fi
 
     Banner "Installing ${file}"
     DownloadOrCopy ${APT_REPO}/pool/${file} ${package}
     if [ ! -s "${package}" ] ; then
       echo
       echo "ERROR: bad package ${package}"
       exit 1
     fi
     echo "${sha256sum}  ${package}" | sha256sum --quiet -c
 
     SubBanner "Extracting to ${INSTALL_ROOT}"
-    dpkg --fsys-tarfile ${package}\
-      | tar -xf - -C ${INSTALL_ROOT}
+    dpkg-deb -x ${package} ${INSTALL_ROOT}
 
+    base_package=$(dpkg-deb --field ${package} Package)
+    mkdir -p ${INSTALL_ROOT}/debian/${base_package}/DEBIAN

[Sam Clegg, 2016/10/11 03:06:46]

How are these "/debian" directories then passed to dpkg-shlibdeps?

It seems a little strange to put all this stuff under /debian in the sysroot.

If it works I don't argue, but hopefully we can switch to more real sysroots
built with debbootstrap soon.

[Tom (Use chromium acct), 2016/10/11 05:33:55]

you cd to the dir containing debian/ and then run dpkg-shlibdeps
yeah it's not standard :(  but I needed some place to stuff the control files. 
It doesn't have to be at the root, but the directory needs to be named debian. 
Maybe /impl/debian would be better??

+    dpkg-deb -e ${package} ${INSTALL_ROOT}/debian/${base_package}/DEBIAN
   done
 
   # Prune /usr/share, leaving only pkgconfig
   for name in ${INSTALL_ROOT}/usr/share/*; do
     if [ "${name}" != "${INSTALL_ROOT}/usr/share/pkgconfig" ]; then
       rm -r ${name}
     fi
   done
 }
 
@@ skipping 411 matching lines @@
   echo "    $0 help"
   exit 1
 else
   ChangeDirectory
   if echo $1 | grep -qs "All$"; then
     "$@"
   else
     RunCommand "$@"
   fi
 fi