busybox/scripts/embedded_scripts
Denys Vlasenko 4f2ef4a836 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>
2018-11-01 10:15:13 +01:00

67 lines
1.1 KiB
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Executable File

#!/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"