busybox: add '--show SCRIPT' option to display scripts

Add an option to allow the content of embedded scripts to be
displayed.  This includes applet scripts, custom scripts and the
.profile script.

function                                             old     new   delta
busybox_main                                         624     701     +77
find_script_by_name                                    -      24     +24
scripted_main                                         41      35      -6
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/1 up/down: 101/-6)             Total: 95 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 59 insertions, 38 deletions

diff --git a/Config.in b/Config.in
index ae21f52..01680af 100644
--- a/Config.in
+++ b/Config.in
@@ -178,6 +178,11 @@ config BUSYBOX
 
 	Running "busybox APPLET [ARGS...]" will still work, of course.
 
+config FEATURE_SHOW_SCRIPT
+	bool "Support --show SCRIPT"
+	default y
+	depends on BUSYBOX
+
 config FEATURE_INSTALLER
 	bool "Support --install [-s] to install applet links at runtime"
 	default y
diff --git a/libbb/appletlib.c b/libbb/appletlib.c
index a0ebaca..a79a37e 100644
--- a/libbb/appletlib.c
+++ b/libbb/appletlib.c
@@ -756,6 +756,44 @@ static void install_links(const char *busybox UNUSED_PARAM,
 
 static void run_applet_and_exit(const char *name, char **argv) NORETURN;
 
+# if NUM_SCRIPTS > 0
+static int find_script_by_name(const char *name)
+{
+	int i;
+	int applet = find_applet_by_name(name);
+
+	if (applet >= 0) {
+		for (i = 0; i < NUM_SCRIPTS; ++i)
+			if (applet_numbers[i] == applet)
+				return i;
+	}
+	return -1;
+}
+
+int scripted_main(int argc UNUSED_PARAM, char **argv)
+{
+	int script = find_script_by_name(applet_name);
+	if (script >= 0)
+		exit(ash_main(-script - 1, argv));
+	return 0;
+}
+
+char* FAST_FUNC
+get_script_content(unsigned n)
+{
+	char *t = unpack_bz2_data(packed_scripts, sizeof(packed_scripts),
+					UNPACKED_SCRIPTS_LENGTH);
+	if (t) {
+		while (n != 0) {
+			while (*t++ != '\0')
+				continue;
+			n--;
+		}
+	}
+	return t;
+}
+# endif /* NUM_SCRIPTS > 0 */
+
 # if ENABLE_BUSYBOX
 #  if ENABLE_FEATURE_SH_STANDALONE && ENABLE_FEATURE_TAB_COMPLETION
     /*
@@ -793,6 +831,9 @@ int busybox_main(int argc UNUSED_PARAM, char **argv)
 			"\n"
 			"Usage: busybox [function [arguments]...]\n"
 			"   or: busybox --list"IF_FEATURE_INSTALLER("[-full]")"\n"
+#  if ENABLE_FEATURE_SHOW_SCRIPT && NUM_SCRIPTS > 0
+			"   or: busybox --show SCRIPT\n"
+#  endif
 			IF_FEATURE_INSTALLER(
 			"   or: busybox --install [-s] [DIR]\n"
 			)
@@ -838,6 +879,19 @@ int busybox_main(int argc UNUSED_PARAM, char **argv)
 		return 0;
 	}
 
+#  if ENABLE_FEATURE_SHOW_SCRIPT && NUM_SCRIPTS > 0
+	if (strcmp(argv[1], "--show") == 0) {
+		int n;
+		if (!argv[2])
+			bb_error_msg_and_die(bb_msg_requires_arg, "--show");
+		n = find_script_by_name(argv[2]);
+		if (n < 0)
+			bb_error_msg_and_die("script '%s' not found", argv[2]);
+		full_write1_str(get_script_content(n));
+		return 0;
+	}
+#  endif
+
 	if (is_prefixed_with(argv[1], "--list")) {
 		unsigned i = 0;
 		const char *a = applet_names;
@@ -939,44 +993,6 @@ void FAST_FUNC run_applet_no_and_exit(int applet_no, const char *name, char **ar
 }
 # endif /* NUM_APPLETS > 0 */
 
-# if NUM_SCRIPTS > 0
-static int find_script_by_name(const char *name)
-{
-	int i;
-	int applet = find_applet_by_name(name);
-
-	if (applet >= 0) {
-		for (i = 0; i < NUM_SCRIPTS; ++i)
-			if (applet_numbers[i] == applet)
-				return i;
-	}
-	return -1;
-}
-
-int scripted_main(int argc UNUSED_PARAM, char **argv)
-{
-	int script = find_script_by_name(applet_name);
-	if (script >= 0)
-		exit(ash_main(-script - 1, argv));
-	return 0;
-}
-
-char* FAST_FUNC
-get_script_content(unsigned n)
-{
-	char *t = unpack_bz2_data(packed_scripts, sizeof(packed_scripts),
-					UNPACKED_SCRIPTS_LENGTH);
-	if (t) {
-		while (n != 0) {
-			while (*t++ != '\0')
-				continue;
-			n--;
-		}
-	}
-	return t;
-}
-# endif /* NUM_SCRIPTS > 0 */
-
 # if ENABLE_BUSYBOX || NUM_APPLETS > 0
 static NORETURN void run_applet_and_exit(const char *name, char **argv)
 {