hush: allow hush to run embedded scripts

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>

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: