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>
This commit is contained in:
Denys Vlasenko 2018-11-01 09:53:25 +01:00
parent 552796791f
commit 4f2ef4a836
9 changed files with 201 additions and 3 deletions

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@ -850,11 +850,14 @@ quiet_cmd_gen_common_bufsiz = GEN include/common_bufsiz.h
cmd_gen_common_bufsiz = $(srctree)/scripts/generate_BUFSIZ.sh include/common_bufsiz.h cmd_gen_common_bufsiz = $(srctree)/scripts/generate_BUFSIZ.sh include/common_bufsiz.h
quiet_cmd_split_autoconf = SPLIT include/autoconf.h -> include/config/* quiet_cmd_split_autoconf = SPLIT include/autoconf.h -> include/config/*
cmd_split_autoconf = scripts/basic/split-include include/autoconf.h include/config cmd_split_autoconf = scripts/basic/split-include include/autoconf.h include/config
quiet_cmd_gen_embedded_scripts = GEN include/embedded_scripts.h
cmd_gen_embedded_scripts = scripts/embedded_scripts include/embedded_scripts.h embed
#bbox# piggybacked generation of few .h files #bbox# piggybacked generation of few .h files
include/config/MARKER: scripts/basic/split-include include/autoconf.h include/config/MARKER: scripts/basic/split-include include/autoconf.h $(wildcard embed/*) scripts/embedded_scripts
$(call cmd,split_autoconf) $(call cmd,split_autoconf)
$(call cmd,gen_bbconfigopts) $(call cmd,gen_bbconfigopts)
$(call cmd,gen_common_bufsiz) $(call cmd,gen_common_bufsiz)
$(call cmd,gen_embedded_scripts)
@touch $@ @touch $@
# Generate some files # Generate some files
@ -974,6 +977,7 @@ MRPROPER_FILES += .config .config.old include/asm .version .old_version \
include/autoconf.h \ include/autoconf.h \
include/bbconfigopts.h \ include/bbconfigopts.h \
include/bbconfigopts_bz2.h \ include/bbconfigopts_bz2.h \
include/embedded_scripts.h \
include/usage_compressed.h \ include/usage_compressed.h \
include/applet_tables.h \ include/applet_tables.h \
include/applets.h \ include/applets.h \

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@ -91,6 +91,7 @@ lib-$(CONFIG_FEATURE_SEAMLESS_LZMA) += open_transformer.o decompress_unlzma.
lib-$(CONFIG_FEATURE_SEAMLESS_XZ) += open_transformer.o decompress_unxz.o lib-$(CONFIG_FEATURE_SEAMLESS_XZ) += open_transformer.o decompress_unxz.o
lib-$(CONFIG_FEATURE_COMPRESS_USAGE) += open_transformer.o decompress_bunzip2.o lib-$(CONFIG_FEATURE_COMPRESS_USAGE) += open_transformer.o decompress_bunzip2.o
lib-$(CONFIG_FEATURE_COMPRESS_BBCONFIG) += open_transformer.o decompress_bunzip2.o lib-$(CONFIG_FEATURE_COMPRESS_BBCONFIG) += open_transformer.o decompress_bunzip2.o
lib-$(CONFIG_ASH_EMBEDDED_SCRIPTS) += open_transformer.o decompress_bunzip2.o
ifneq ($(lib-y),) ifneq ($(lib-y),)
lib-y += $(COMMON_FILES) lib-y += $(COMMON_FILES)

1
include/.gitignore vendored
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@ -5,6 +5,7 @@
/autoconf.h /autoconf.h
/bbconfigopts_bz2.h /bbconfigopts_bz2.h
/bbconfigopts.h /bbconfigopts.h
/embedded_scripts.h
/NUM_APPLETS.h /NUM_APPLETS.h
/usage_compressed.h /usage_compressed.h
/usage.h /usage.h

View File

@ -1321,9 +1321,17 @@ void bb_logenv_override(void) FAST_FUNC;
#define MAIN_EXTERNALLY_VISIBLE #define MAIN_EXTERNALLY_VISIBLE
#endif #endif
/* Embedded script support */
//int find_script_by_name(const char *arg IF_FEATURE_SH_STANDALONE(, int offset)) FAST_FUNC;
char *get_script_content(unsigned n) FAST_FUNC;
/* Applets which are useful from another applets */ /* Applets which are useful from another applets */
int bb_cat(char** argv) FAST_FUNC; int bb_cat(char** argv) FAST_FUNC;
int ash_main(int argc, char** argv)
#if ENABLE_ASH || ENABLE_SH_IS_ASH || ENABLE_BASH_IS_ASH
MAIN_EXTERNALLY_VISIBLE
#endif
;
/* If shell needs them, they exist even if not enabled as applets */ /* If shell needs them, they exist even if not enabled as applets */
int echo_main(int argc, char** argv) IF_ECHO(MAIN_EXTERNALLY_VISIBLE); int echo_main(int argc, char** argv) IF_ECHO(MAIN_EXTERNALLY_VISIBLE);
int printf_main(int argc, char **argv) IF_PRINTF(MAIN_EXTERNALLY_VISIBLE); int printf_main(int argc, char **argv) IF_PRINTF(MAIN_EXTERNALLY_VISIBLE);

View File

@ -50,6 +50,16 @@
#include "usage_compressed.h" #include "usage_compressed.h"
#if ENABLE_ASH_EMBEDDED_SCRIPTS
# define DEFINE_script_names 1
# include "embedded_scripts.h"
#else
# define NUM_SCRIPTS 0
#endif
#if NUM_SCRIPTS > 0
# include "bb_archive.h"
static const char packed_scripts[] ALIGN1 = { PACKED_SCRIPTS };
#endif
/* "Do not compress usage text if uncompressed text is small /* "Do not compress usage text if uncompressed text is small
* and we don't include bunzip2 code for other reasons" * and we don't include bunzip2 code for other reasons"
@ -953,7 +963,71 @@ void FAST_FUNC run_applet_no_and_exit(int applet_no, const char *name, char **ar
} }
# endif /* NUM_APPLETS > 0 */ # endif /* NUM_APPLETS > 0 */
# if ENABLE_BUSYBOX || NUM_APPLETS > 0 # if NUM_SCRIPTS > 0
static char *
unpack_scripts(void)
{
char *outbuf = NULL;
bunzip_data *bd;
int i;
jmp_buf jmpbuf;
/* Setup for I/O error handling via longjmp */
i = setjmp(jmpbuf);
if (i == 0) {
i = start_bunzip(&jmpbuf,
&bd,
/* src_fd: */ -1,
/* inbuf: */ packed_scripts,
/* len: */ sizeof(packed_scripts)
);
}
/* read_bunzip can longjmp and end up here with i != 0
* on read data errors! Not trivial */
if (i == 0) {
outbuf = xmalloc(UNPACKED_SCRIPTS_LENGTH);
read_bunzip(bd, outbuf, UNPACKED_SCRIPTS_LENGTH);
}
dealloc_bunzip(bd);
return outbuf;
}
/*
* In standalone shell mode we sometimes want the index of the script
* and sometimes the index offset by NUM_APPLETS.
*/
static int
find_script_by_name(const char *arg)
{
const char *s = script_names;
int i = 0;
while (*s) {
if (strcmp(arg, s) == 0)
return i;
i++;
while (*s++ != '\0')
continue;
}
return -1;
}
char* FAST_FUNC
get_script_content(unsigned n)
{
char *t = unpack_scripts();
if (t) {
while (n != 0) {
while (*t++ != '\0')
continue;
n--;
}
}
return t;
}
# endif /* NUM_SCRIPTS > 0 */
# if ENABLE_BUSYBOX || NUM_APPLETS > 0 || NUM_SCRIPTS > 0
static NORETURN void run_applet_and_exit(const char *name, char **argv) static NORETURN void run_applet_and_exit(const char *name, char **argv)
{ {
# if ENABLE_BUSYBOX # if ENABLE_BUSYBOX
@ -968,6 +1042,13 @@ static NORETURN void run_applet_and_exit(const char *name, char **argv)
run_applet_no_and_exit(applet, name, argv); run_applet_no_and_exit(applet, name, argv);
} }
# endif # endif
# if NUM_SCRIPTS > 0
{
int script = find_script_by_name(name);
if (script >= 0)
exit(ash_main(-script - 1, argv));
}
# endif
/*bb_error_msg_and_die("applet not found"); - links in printf */ /*bb_error_msg_and_die("applet not found"); - links in printf */
full_write2_str(applet_name); full_write2_str(applet_name);

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@ -41,6 +41,12 @@
#include "busybox.h" #include "busybox.h"
#include "NUM_APPLETS.h" #include "NUM_APPLETS.h"
#include "unicode.h" #include "unicode.h"
#if ENABLE_ASH_EMBEDDED_SCRIPTS
# include "embedded_scripts.h"
#else
# define NUM_SCRIPTS 0
#endif
#ifndef _POSIX_VDISABLE #ifndef _POSIX_VDISABLE
# define _POSIX_VDISABLE '\0' # define _POSIX_VDISABLE '\0'
#endif #endif

66
scripts/embedded_scripts Executable file
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@ -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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@ -148,6 +148,21 @@
//config: you to run the specified command or builtin, //config: you to run the specified command or builtin,
//config: even when there is a function with the same name. //config: even when there is a function with the same name.
//config: //config:
//config:config ASH_EMBEDDED_SCRIPTS
//config: bool "Embed scripts in the binary"
//config: default y
//config: depends on ASH || SH_IS_ASH || BASH_IS_ASH
//config: help
//config: Allow scripts to be compressed and embedded in the BusyBox
//config: binary. The scripts should be placed in the 'embed' directory
//config: at build time. In standalone shell mode such scripts can be
//config: run directly and are subject to tab completion; otherwise they
//config: can be run by giving their name as an argument to the shell.
//config: For convenience shell aliases are created. The '-L' shell
//config: argument lists the names of the scripts. Like applets scripts
//config: can be run as 'busybox name ...' or by linking their name to
//config: the binary.
//config:
//config:endif # ash options //config:endif # ash options
//applet:IF_ASH(APPLET(ash, BB_DIR_BIN, BB_SUID_DROP)) //applet:IF_ASH(APPLET(ash, BB_DIR_BIN, BB_SUID_DROP))
@ -181,6 +196,11 @@
#include <sys/times.h> #include <sys/times.h>
#include <sys/utsname.h> /* for setting $HOSTNAME */ #include <sys/utsname.h> /* for setting $HOSTNAME */
#include "busybox.h" /* for applet_names */ #include "busybox.h" /* for applet_names */
#if ENABLE_ASH_EMBEDDED_SCRIPTS
# include "embedded_scripts.h"
#else
# define NUM_SCRIPTS 0
#endif
/* So far, all bash compat is controlled by one config option */ /* So far, all bash compat is controlled by one config option */
/* Separate defines document which part of code implements what */ /* Separate defines document which part of code implements what */
@ -14021,13 +14041,17 @@ procargs(char **argv)
int login_sh; int login_sh;
xargv = argv; xargv = argv;
#if NUM_SCRIPTS > 0
if (minusc)
goto setarg0;
#endif
login_sh = xargv[0] && xargv[0][0] == '-'; login_sh = xargv[0] && xargv[0][0] == '-';
arg0 = xargv[0]; arg0 = xargv[0];
/* if (xargv[0]) - mmm, this is always true! */ /* if (xargv[0]) - mmm, this is always true! */
xargv++; xargv++;
argptr = xargv;
for (i = 0; i < NOPTS; i++) for (i = 0; i < NOPTS; i++)
optlist[i] = 2; optlist[i] = 2;
argptr = xargv;
if (options(/*cmdline:*/ 1, &login_sh)) { if (options(/*cmdline:*/ 1, &login_sh)) {
/* it already printed err message */ /* it already printed err message */
raise_exception(EXERROR); raise_exception(EXERROR);
@ -14130,6 +14154,7 @@ extern int etext();
*/ */
int ash_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int ash_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int ash_main(int argc UNUSED_PARAM, char **argv) int ash_main(int argc UNUSED_PARAM, char **argv)
/* note: 'argc' is used only if embedded scripts are enabled */
{ {
volatile smallint state; volatile smallint state;
struct jmploc jmploc; struct jmploc jmploc;
@ -14183,6 +14208,12 @@ int ash_main(int argc UNUSED_PARAM, char **argv)
init(); init();
setstackmark(&smark); setstackmark(&smark);
#if NUM_SCRIPTS > 0
if (argc < 0)
/* Non-NULL minusc tells procargs that an embedded script is being run */
minusc = get_script_content(-argc - 1);
#endif
login_sh = procargs(argv); login_sh = procargs(argv);
#if DEBUG #if DEBUG
TRACE(("Shell args: ")); TRACE(("Shell args: "));