From 4f2ef4a836be37b25808c94f41c7c85895db6f93 Mon Sep 17 00:00:00 2001
From: Denys Vlasenko
Date: Thu, 1 Nov 2018 09:53:25 +0100
Subject: ash: allow shell scripts to be embedded in the binary

To assist in the deployment of shell scripts it may be convenient
to embed them in the BusyBox binary.

'Embed scripts in the binary' takes any files in the directory
'embed', concatenates them with null separators, compresses them
and embeds them in the binary.

When scripts are embedded in the binary, scripts can be run as
'busybox SCRIPT [ARGS]' or by usual (sym)link mechanism.

embed/nologin is provided as an example.

function                                             old     new   delta
packed_scripts                                         -     123    +123
unpack_scripts                                         -      87     +87
ash_main                                            1103    1171     +68
run_applet_and_exit                                   78     128     +50
get_script_content                                     -      32     +32
script_names                                           -      10     +10
expmeta                                              663     659      -4
------------------------------------------------------------------------------
(add/remove: 4/0 grow/shrink: 2/1 up/down: 370/-4)            Total: 366 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
---
 scripts/embedded_scripts | 66 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100755 scripts/embedded_scripts

(limited to 'scripts')

diff --git a/scripts/embedded_scripts b/scripts/embedded_scripts
new file mode 100755
index 0000000..986e851
--- /dev/null
+++ b/scripts/embedded_scripts
@@ -0,0 +1,66 @@
+#!/bin/sh
+
+target="$1"
+loc="$2"
+
+test "$target" || exit 1
+test "$SED" || SED=sed
+test "$DD" || DD=dd
+
+# Some people were bitten by their system lacking a (proper) od
+od -v -b </dev/null >/dev/null
+if test $? != 0; then
+	echo 'od tool is not installed or cannot accept "-v -b" options'
+	exit 1
+fi
+
+exec >"$target.$$"
+
+scripts=""
+if [ -d "$loc" ]
+then
+	scripts=$(cd $loc; ls * 2>/dev/null)
+fi
+
+n=$(echo $scripts | wc -w)
+
+if [ $n -ne 0 ]
+then
+	printf '#ifdef DEFINE_script_names\n'
+	printf 'const char script_names[] ALIGN1 = '
+	for i in $scripts
+	do
+		printf '"%s\\0"' $i
+	done
+	printf '"\\0";\n'
+	printf '#else\n'
+	printf 'extern const char script_names[] ALIGN1;\n'
+	printf '#endif\n'
+fi
+printf "#define NUM_SCRIPTS $n\n\n"
+
+if [ $n -ne 0 ]
+then
+	printf '#define UNPACKED_SCRIPTS_LENGTH '
+	for i in $scripts
+	do
+		cat $loc/$i
+		printf '\000'
+	done | wc -c
+
+	printf '#define PACKED_SCRIPTS \\\n'
+	for i in $scripts
+	do
+		cat $loc/$i
+		printf '\000'
+	done | bzip2 -1 | $DD bs=2 skip=1 2>/dev/null | od -v -b \
+	| grep -v '^ ' \
+	| $SED -e 's/^[^ ]*//' \
+		-e 's/ //g' \
+		-e '/^$/d' \
+		-e 's/\(...\)/0\1,/g' \
+		-e 's/$/ \\/'
+	printf '\n'
+fi
+
+mv -- "$target.$$" "$target"
-- 
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