1 files changed, 42 insertions, 0 deletions
diff --git a/debian/usrmerge.preinst b/debian/usrmerge.preinst
new file mode 100644
index 0000000..cc356eb
--- /dev/null
+++ b/debian/usrmerge.preinst
@@ -0,0 +1,42 @@
+#!/bin/sh -e
+
+is_mountpoint() {
+  if mountpoint -q "$1"; then
+    return 0
+  fi
+  return 1 # not a mount point
+}
+
+standalone_usr() {
+  if is_mountpoint /usr; then
+    return 0
+  fi
+  return 1
+}
+
+booted_with_initramfs() {
+  # created by update-initramfs
+  if [ -d /run/initramfs/ ]; then
+    return 1
+  fi
+  return 0
+}
+
+has_initramfs() {
+  standalone_usr || return 0
+  booted_with_initramfs || return 0
+  echo "/usr is a standalone filesystem, this requires using an initramfs."
+  exit 1
+}
+
+case "$1" in
+    install)
+    # check the prerequisites on the first install
+    if [ -z "$2" ]; then
+	has_initramfs
+    fi
+    ;;
+esac
+
+#DEBHELPER#
+