initramfs-tools: add sources and use them.

* Add source files directly to avoid recreating patches and
  patches lots of times with no gain.
* Add du and expr busybox symlinks at init time.

Bump revision.

--HG--
extra : convert_revision : 4928750b0110f43cde577f6068e79bd0675c64cf

templates/initramfs-tools/files/docs/example_hook

@@ -0,0 +1,114 @@
+#!/bin/sh
+
+#
+# This is an example hook script.  It will be run by 'mkinitramfs'
+# when it creates the image.  It's job is to decide which files to
+# install, then install them into the staging area, where the
+# initramfs is being created.  This happens when a new 'linux-image'
+# package is installed, or when the administrator runs 'mkinitramfs'
+# by hand to update an initramfs image.
+#
+# TODO: What about the case where you install something that should be
+#	added to the initramfs, but the linux-image it relates to has
+#	already been installed previously?  Does this happen often
+#	enough that it needs to be handled?  How can it be handled?
+#
+#	* Think about the 'usplash'.  The initramfs will need to be
+#	 updated if a theme change or update is desired.  Maybe it
+#	 should not be totally automatic, but offered on upgrade
+#	 predicated on a user response to a debconf question?  That
+#	 issue needs to be explored and a solution specified.
+#
+#  * Do not assume that any needed subdirectories have been created
+#	yet, but don't bail out if they are already there.
+#
+#  * All of the standard system tools are available, of course, since
+#	this hook is running in the real system, not the initramfs.
+#
+#  * TODO: ... ?  Anything else to tell them in this bullet-list?
+#
+
+#
+# The environment contains at least:
+#
+#  CONFDIR -- usually /etc/mkinitramfs, can be set on mkinitramfs
+#		 command line.
+#
+#  DESTDIR -- The staging directory where we are building the image.
+#
+# TODO: Decide what environment variables are meaningful and defined
+#	in this context, then document them as part of the interface.
+#
+# TODO: May need a version_compare function for comparison of VERSION?
+
+
+#
+# List the soft prerequisites here.  This is a space separated list of
+# names, of scripts that are in the same directory as this one, that
+# must be run before this one can be.
+#
+PREREQ=""
+
+prereqs()
+{
+	echo "$PREREQ"
+}
+
+case $1 in
+# get pre-requisites
+prereqs)
+	prereqs
+	exit 0
+	;;
+esac
+
+
+# You can do anything you need to from here on.
+#
+
+# Source the optional 'hook-functions' scriptlet, if you need the
+# functions defined within it.  Read it to see what is available to
+# you.  It contains functions for copying dynamically linked program
+# binaries, and kernel modules into the DESTDIR.
+#
+. /usr/share/initramfs-tools/hook-functions
+
+
+# If this hook script is a conffile (and thus stored in
+# /etc/mkinitramfs/hooks), it must take care to do the right thing
+# when the package containing it is removed but not purged.  There of
+# course may be other reasons to have custom logic deciding what to
+# install.  The version variable may be useful for this.
+#
+if [ -x /usr/bin/myprog ]; then
+	copy_exec /usr/bin/myprog usr/bin
+fi
+
+# To accompany this, there should usually be a script for inside the
+# initramfs named something like:
+#
+#   "/etc/mkinitramfs/local-premount/myprog"
+#
+# ... and it should do what is necessary to have 'myprog' get run
+# inside the early runtime environment.
+
+# Handle an error:
+#
+if [ -n "$an_error_occured" ];
+then
+	#
+	# TODO: Do we need 'warn()', 'error()', and/or 'fatal()' for this?
+	#
+	echo "An error occured in $0: $an_error_occured" >&2
+	exit 1
+	#
+	# TODO: Decide if different error codes are meaningful, what they
+	#	mean, and what the semantics of them are wrt 'mkinitramfs'
+	#	pass or fail.  Consider naming the error values with
+	#	mnemonic symbols rather than magic numbers.  They may or
+	#	may not be the same set of errors as the set for
+	#	in-initramfs scripts.
+	#
+fi
+
+exit 0