[PATCH] hush: allow hush to run embedded scripts
Denys Vlasenko
vda.linux at googlemail.com
Tue Nov 27 15:14:30 UTC 2018
Applied, thanks!
On Tue, Nov 27, 2018 at 3:34 PM Ron Yorston <rmy at pobox.com> wrote:
>
> 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 at pobox.com>
> ---
> archival/libarchive/Kbuild.src | 2 +-
> docs/embedded-scripts.txt | 21 ++++++++-------------
> include/libbb.h | 5 +++++
> libbb/appletlib.c | 8 +++++++-
> scripts/embedded_scripts | 8 ++++++++
> scripts/gen_build_files.sh | 2 +-
> shell/Config.src | 14 ++++++++++++++
> shell/ash.c | 16 +---------------
> shell/hush.c | 16 ++++++++++++++++
> util-linux/nologin.c | 2 +-
> 10 files changed, 62 insertions(+), 32 deletions(-)
>
> diff --git a/archival/libarchive/Kbuild.src b/archival/libarchive/Kbuild.src
> index 12e66a88b..d2f284b08 100644
> --- a/archival/libarchive/Kbuild.src
> +++ b/archival/libarchive/Kbuild.src
> @@ -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)
> diff --git a/docs/embedded-scripts.txt b/docs/embedded-scripts.txt
> index 1b0c5b591..7a273d698 100644
> --- a/docs/embedded-scripts.txt
> +++ b/docs/embedded-scripts.txt
> @@ -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
> diff --git a/include/libbb.h b/include/libbb.h
> index ebd090e18..b560cc2eb 100644
> --- a/include/libbb.h
> +++ b/include/libbb.h
> @@ -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);
> diff --git a/libbb/appletlib.c b/libbb/appletlib.c
> index a79a37efb..cd09b620c 100644
> --- a/libbb/appletlib.c
> +++ b/libbb/appletlib.c
> @@ -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;
> }
>
> diff --git a/scripts/embedded_scripts b/scripts/embedded_scripts
> index 86ad44d1d..aa7bf3e8a 100755
> --- a/scripts/embedded_scripts
> +++ b/scripts/embedded_scripts
> @@ -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
> diff --git a/scripts/gen_build_files.sh b/scripts/gen_build_files.sh
> index 362632df3..92de681ac 100755
> --- a/scripts/gen_build_files.sh
> +++ b/scripts/gen_build_files.sh
> @@ -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
> }
> diff --git a/shell/Config.src b/shell/Config.src
> index 959d3cb42..bc7218fe5 100644
> --- a/shell/Config.src
> +++ b/shell/Config.src
> @@ -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
> diff --git a/shell/ash.c b/shell/ash.c
> index 04e4006c8..9ce1d1a76 100644
> --- a/shell/ash.c
> +++ b/shell/ash.c
> @@ -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
> diff --git a/shell/hush.c b/shell/hush.c
> index 431010f09..90191408d 100644
> --- a/shell/hush.c
> +++ b/shell/hush.c
> @@ -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();
> diff --git a/util-linux/nologin.c b/util-linux/nologin.c
> index 0982fff3d..5e5e42305 100644
> --- a/util-linux/nologin.c
> +++ b/util-linux/nologin.c
> @@ -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:
> --
> 2.19.1
>
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