1 files changed, 92 insertions, 0 deletions
diff --git a/debian/usrmerge.postinst b/debian/usrmerge.postinst
new file mode 100644
index 0000000..4f2482d
--- /dev/null
+++ b/debian/usrmerge.postinst
@@ -0,0 +1,92 @@
+#!/bin/sh
+set -e
+
+is_fs() {
+  local fs_type
+  fs_type="$(stat --file-system --format=%T "$2" 2> /dev/null)"
+
+  if [ "$fs_type" = "$1" ]; then return 0; fi
+  return 1
+}
+
+is_merged() {
+  local directories="/bin /sbin /lib"
+  for dir in $directories; do
+    [ -e "$dir" ] || continue
+    [ "$(readlink -f "$dir")" = "/usr$dir" ] || return 1
+  done
+
+  # Avoid an exact match, as the target might vary depending on the tool
+  # building the image. For example, systemd-nspawn links /lib64 to
+  # /usr/lib/aarch64-linux-gnu on arm64, while on amd64 debootstrap links it to
+  # /usr/lib64 and doesn't create it at all on arm64.
+  # See: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1019575
+  local arch_directories="/lib64 /lib32 /libo32 /libx32"
+  for dir in $arch_directories; do
+    [ -e "$dir" ] || continue
+    case "$(readlink -f "$dir")" in
+        "/usr/lib"*) ;;
+        *) return 1;;
+    esac
+  done
+
+  return 0
+}
+
+maybe_convert() {
+  # do not try to run the program if the system has already been converted
+  if is_merged; then return; fi
+
+  if is_fs nfs / || is_fs nfs /usr; then
+    cat << 'END' >&2
+
+Warning: NFS detected, /usr/lib/usrmerge/convert-usrmerge will not be run
+automatically. See #842145 for details.
+
+END
+    return 1
+  fi
+
+  /usr/lib/usrmerge/convert-usrmerge || return $?
+
+  if which update-shells > /dev/null; then
+    update-shells
+  fi
+  /usr/lib/usrmerge/convert-etc-shells || return $?
+}
+
+cleanup_biarch_dirs() {
+  dpkg --compare-versions "$2" lt "36~" || return 0
+
+  # bootstrapping or earlier conversions may have created empty biarch
+  # directories and links. glibc 2.35-4 or later will create them if needed,
+  # so clean up the unused (and unowned) ones
+  local arch_directories="/lib64 /lib32 /libo32 /libx32"
+  for dir in $arch_directories; do
+    [ -e "$dir" ] || continue
+    if ! dpkg-query -S $dir >/dev/null 2>&1; then
+      rm -v $dir
+      if [ -e /usr$dir ] && ! dpkg-query -S /usr$dir >/dev/null 2>&1 ; then
+        rmdir --ignore-fail-on-non-empty -v /usr$dir
+      fi
+    fi
+  done
+}
+
+case "$1" in
+    configure)
+	# skipping the conversion is not supported anymore
+	if [ -e /etc/unsupported-skip-usrmerge-conversion ] && \
+	    grep -q 'this system will not be supported in the future' \
+	      /etc/unsupported-skip-usrmerge-conversion; then
+	  echo "E: /etc/unsupported-skip-usrmerge-conversion exists." >&2
+	  exit 1
+	else
+	  maybe_convert "$@" || { echo "E: usrmerge failed." >&2; exit 1; }
+	  cleanup_biarch_dirs
+	fi
+    ;;
+esac
+
+#DEBHELPER#
+