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hush: allow hush to run embedded scripts

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Embedded scripts require a shell to be present in the BusyBox
binary.  Allow either ash or hush to be used for this purpose.
If both are enabled ash takes precedence.

The size of the binary is unchanged in the default configuration:
both ash and hush are present but support for embedded scripts
isn't compiled into hush.

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Ron Yorston 2018-11-27 14:34:25 +00:00 committed by Denys Vlasenko
parent f4709d78cb
commit 71df2d3589
10 changed files with 62 additions and 32 deletions
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2
archival/libarchive/Kbuild.src
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@ -91,7 +91,7 @@ lib-$(CONFIG_FEATURE_SEAMLESS_LZMA) += open_transformer.o decompress_unlzma.
lib-$(CONFIG_FEATURE_SEAMLESS_XZ) += open_transformer.o decompress_unxz.o
lib-$(CONFIG_FEATURE_COMPRESS_USAGE) += open_transformer.o decompress_bunzip2.o
lib-$(CONFIG_FEATURE_COMPRESS_BBCONFIG) += open_transformer.o decompress_bunzip2.o
lib-$(CONFIG_ASH_EMBEDDED_SCRIPTS) += open_transformer.o decompress_bunzip2.o
lib-$(CONFIG_FEATURE_SH_EMBEDDED_SCRIPTS) += open_transformer.o decompress_bunzip2.o
ifneq ($(lib-y),)
lib-y += $(COMMON_FILES)

21
docs/embedded-scripts.txt
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@ -3,13 +3,9 @@ Embedded Shell Scripts in BusyBox
BusyBox allows applets to be implemented as shell scripts. Since
this obviously requires a shell to interpret the scripts the feature
depends on having a shell (specifically, ash) built into the binary.
Support for embedded scripts also has to be enabled.
To embed scripts in BusyBox you must enable these configuration options:
ASH
ASH_EMBEDDED_SCRIPTS
depends on having a shell built into the binary. Either ash or hush
will do. If both are present ash will be used. Support for embedded
scripts also has to be enabled.
It's unlikely that your applet will be implemented as a pure shell
script: it will probably need some external commands. If these are
@ -75,10 +71,9 @@ code for the native applet:
The only difference is that the applet is specified as being of type
APPLET_SCRIPTED. It would also be useful to include details of any
dependencies the script has. We can assume that ash is available.
No external commands are used by our mu script, but it does depend on
optional shell features. We can ensure these are selected by adding
this to the configuration:
dependencies the script has. No external commands are used by our mu
script, but it does depend on optional shell features. We can ensure
these are selected by adding this to the configuration:
//config:config MU_DEPENDENCIES
//config: bool "Enable dependencies for mu"
@ -87,8 +82,8 @@ this to the configuration:
//config: select ASH_RANDOM_SUPPORT
//config: select FEATURE_SH_MATH
//config: help
//config: mu is implemented as a shell script. It requires ash
//config: support for $RANDOM and arithmetic.
//config: mu is implemented as a shell script. It requires support
//config: for $RANDOM and arithmetic.
The configuration data should be placed in a C file in an appropriate
subdirectory. There isn't any C code, though! In this case the file

5
include/libbb.h
View File

@ -1348,6 +1348,11 @@ int ash_main(int argc, char** argv)
MAIN_EXTERNALLY_VISIBLE
#endif
;
int hush_main(int argc, char** argv)
#if ENABLE_HUSH || ENABLE_SH_IS_HUSH || ENABLE_BASH_IS_HUSH
MAIN_EXTERNALLY_VISIBLE
#endif
;
/* 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 printf_main(int argc, char **argv) IF_PRINTF(MAIN_EXTERNALLY_VISIBLE);

8
libbb/appletlib.c
View File

@ -50,7 +50,7 @@
#include "usage_compressed.h"
#if ENABLE_ASH_EMBEDDED_SCRIPTS
#if ENABLE_FEATURE_SH_EMBEDDED_SCRIPTS
# define DEFINE_SCRIPT_DATA 1
# include "embedded_scripts.h"
#else
@ -774,7 +774,13 @@ int scripted_main(int argc UNUSED_PARAM, char **argv)
{
int script = find_script_by_name(applet_name);
if (script >= 0)
#if ENABLE_ASH || ENABLE_SH_IS_ASH || ENABLE_BASH_IS_ASH
exit(ash_main(-script - 1, argv));
#elif ENABLE_HUSH || ENABLE_SH_IS_HUSH || ENABLE_BASH_IS_HUSH
exit(hush_main(-script - 1, argv));
#else
return 1;
#endif
return 0;
}

8
scripts/embedded_scripts
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@ -1,5 +1,7 @@
#!/bin/sh
. ./.config || exit 1
target="$1"
custom_loc="$2"
applet_loc="$3"
@ -8,6 +10,12 @@ test "$target" || exit 1
test "$SED" || SED=sed
test "$DD" || DD=dd
if [ x"$CONFIG_FEATURE_SH_EMBEDDED_SCRIPTS" != x"y" ]
then
printf '#define NUM_SCRIPTS 0\n' >"$target"
exit 0
fi
# Some people were bitten by their system lacking a (proper) od
od -v -b </dev/null >/dev/null
if test $? != 0; then

2
scripts/gen_build_files.sh
View File

@ -25,7 +25,7 @@ custom_scripts()
then
for i in $(cd "$custom_loc"; ls * 2>/dev/null)
do
printf "APPLET_SCRIPTED(%s, scripted, BB_DIR_USR_BIN, BB_SUID_DROP, scripted)\n" $i;
printf "IF_FEATURE_SH_EMBEDDED_SCRIPTS(APPLET_SCRIPTED(%s, scripted, BB_DIR_USR_BIN, BB_SUID_DROP, scripted))\n" $i;
done
fi
}

14
shell/Config.src
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@ -161,6 +161,20 @@ config FEATURE_SH_HISTFILESIZE
to set shell history size. Note that its max value is capped
by "History size" setting in library tuning section.
config FEATURE_SH_EMBEDDED_SCRIPTS
bool "Embed scripts in the binary"
default y
depends on ASH || HUSH || SH_IS_ASH || BASH_IS_ASH || SH_IS_HUSH || BASH_IS_HUSH
help
Allow scripts to be compressed and embedded in the busybox
binary. The scripts should be placed in the 'embed' directory
at build time. Like applets, scripts can be run as
'busybox SCRIPT ...' or by linking their name to the binary.
This also allows applets to be implemented as scripts: place
the script in 'applets_sh' and a stub C file containing
configuration in the appropriate subsystem directory.
endif # Options common to all shells
endmenu

16
shell/ash.c
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@ -148,20 +148,6 @@
//config: you to run the specified command or builtin,
//config: even when there is a function with the same name.
//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. Like applets, scripts can be run as
//config: 'busybox SCRIPT ...' or by linking their name to the binary.
//config:
//config: This also allows applets to be implemented as scripts: place
//config: the script in 'applets_sh' and a stub C file containing
//config: configuration in the appropriate subsystem directory.
//config:
//config:endif # ash options
//applet:IF_ASH(APPLET(ash, BB_DIR_BIN, BB_SUID_DROP))
@ -195,7 +181,7 @@
#include <sys/times.h>
#include <sys/utsname.h> /* for setting $HOSTNAME */
#include "busybox.h" /* for applet_names */
#if ENABLE_ASH_EMBEDDED_SCRIPTS
#if ENABLE_FEATURE_SH_EMBEDDED_SCRIPTS
# include "embedded_scripts.h"
#else
# define NUM_SCRIPTS 0

16
shell/hush.c
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@ -367,6 +367,11 @@
# define PIPE_BUF 4096 /* amount of buffering in a pipe */
#endif
#if ENABLE_FEATURE_SH_EMBEDDED_SCRIPTS && !(ENABLE_ASH || ENABLE_SH_IS_ASH || ENABLE_BASH_IS_ASH)
# include "embedded_scripts.h"
#else
# define NUM_SCRIPTS 0
#endif
/* So far, all bash compat is controlled by one config option */
/* Separate defines document which part of code implements what */
@ -9951,6 +9956,14 @@ int hush_main(int argc, char **argv)
/* http://www.opengroup.org/onlinepubs/9699919799/utilities/sh.html */
flags = (argv[0] && argv[0][0] == '-') ? OPT_login : 0;
builtin_argc = 0;
#if NUM_SCRIPTS > 0
if (argc < 0) {
optarg = get_script_content(-argc - 1);
optind = 0;
argc = string_array_len(argv);
goto run_script;
}
#endif
while (1) {
int opt = getopt(argc, argv, "+c:exinsl"
#if !BB_MMU
@ -9974,6 +9987,9 @@ int hush_main(int argc, char **argv)
* Note: the form without ARG0 never happens:
* sh ... -c 'builtin' BARGV... ""
*/
#if NUM_SCRIPTS > 0
run_script:
#endif
if (!G.root_pid) {
G.root_pid = getpid();
G.root_ppid = getppid();

2
util-linux/nologin.c
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@ -1,7 +1,7 @@
//config:config NOLOGIN
//config: bool "nologin"
//config: default y
//config: depends on ASH_EMBEDDED_SCRIPTS
//config: depends on FEATURE_SH_EMBEDDED_SCRIPTS
//config: help
//config: Politely refuse a login
//config: