shells: do not frocibly enable test, echo and kill _applets_,

just build relevant source and use xxx_main functions.
build system: add a special case when we have exactly one applet enabled
(makes "true", "false", "basename" REALLY tiny).
getopt32: do not use stdio.

function                                             old     new   delta
getopt32                                            1385    1412     +27
make_device                                         1187    1200     +13
basename_main                                        120     127      +7
tcpudpsvd_main                                      1922    1926      +4
testcmd                                                5       -      -5
echocmd                                                5       -      -5
fuser_main                                          1243    1231     -12
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 4/1 up/down: 51/-22)             Total: 29 bytes

applets/applet_tables.c

@@ -69,9 +69,14 @@ int main(int argc, char **argv)
 
 	/* Keep in sync with include/busybox.h! */
 
-	puts("/* This is a generated file, don't edit */");
+	puts("/* This is a generated file, don't edit */\n");
 
-	puts("const char applet_names[] ALIGN1 = \"\"\n");
+	if (NUM_APPLETS == 1) {
+		printf("#define SINGLE_APPLET_STR \"%s\"\n", applets[0].name);
+		printf("#define SINGLE_APPLET_MAIN %s_main\n\n", applets[0].name);
+	}
+
+	puts("const char applet_names[] ALIGN1 = \"\"");
 	for (i = 0; i < NUM_APPLETS; i++) {
 		printf("\"%s\" \"\\0\"\n", applets[i].name);
 	}

coreutils/Kbuild

@@ -30,6 +30,7 @@ lib-$(CONFIG_DOS2UNIX)  += dos2unix.o
 lib-$(CONFIG_DU)        += du.o
 lib-$(CONFIG_ECHO)      += echo.o
 lib-$(CONFIG_ASH)       += echo.o # used by ash
+lib-$(CONFIG_HUSH)      += echo.o # used by hush
 lib-$(CONFIG_ENV)       += env.o
 lib-$(CONFIG_EXPR)      += expr.o
 lib-$(CONFIG_EXPAND)    += expand.o
@@ -72,6 +73,8 @@ lib-$(CONFIG_TAIL)      += tail.o
 lib-$(CONFIG_TEE)       += tee.o
 lib-$(CONFIG_TEST)      += test.o
 lib-$(CONFIG_ASH)       += test.o # used by ash
+lib-$(CONFIG_HUSH)      += test.o # used by hush
+lib-$(CONFIG_MSH)       += test.o # used by msh
 lib-$(CONFIG_TOUCH)     += touch.o
 lib-$(CONFIG_TR)        += tr.o
 lib-$(CONFIG_TRUE)      += true.o

coreutils/basename.c

@@ -37,15 +37,16 @@ int basename_main(int argc, char **argv)
 	/* It should strip slash: /abc/def/ -> def */
 	s = bb_get_last_path_component_strip(*++argv);
 
+	m = strlen(s);
 	if (*++argv) {
 		n = strlen(*argv);
-		m = strlen(s);
 		if ((m > n) && ((strcmp)(s+m-n, *argv) == 0)) {
-			s[m-n] = '\0';
+			m -= n;
+			s[m] = '\0';
 		}
 	}
 
-	puts(s);
+	/* puts(s) will do, but we can do without stdio this way: */
-
+	s[m++] = '\n';
-	return fflush(stdout);
+	return full_write(STDOUT_FILENO, s, m) == m;
 }

coreutils/echo.c

@@ -27,10 +27,8 @@
 
 /* This is a NOFORK applet. Be very careful! */
 
-/* argc is unused, but removing it precludes compiler from
+/* NB: can be used by shell even if not enabled as applet */
- * using call -> jump optimization */
 
-int echo_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int echo_main(int argc ATTRIBUTE_UNUSED, char **argv)
 {
 	const char *arg;

include/busybox.h

@@ -59,9 +59,6 @@ extern const uint8_t applet_install_loc[];
 /* Length of these names has effect on size of libbusybox
  * and "individual" binaries. Keep them short.
  */
-void lbb_prepare(const char *applet
-	USE_FEATURE_INDIVIDUAL(, char **argv)
-	) MAIN_EXTERNALLY_VISIBLE;
 #if ENABLE_BUILD_LIBBUSYBOX
 #if ENABLE_FEATURE_SHARED_BUSYBOX
 int lbb_main(char **argv) EXTERNALLY_VISIBLE;

include/libbb.h

@@ -848,23 +848,20 @@ extern void bb_verror_msg(const char *s, va_list p, const char *strerr);
 
 /* applets which are useful from another applets */
 int bb_cat(char** argv);
-int echo_main(int argc, char** argv) MAIN_EXTERNALLY_VISIBLE;
+/* If shell needs them, these three "exist" even if not enabled as applets */
-int test_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int echo_main(int argc, char** argv) USE_ECHO(MAIN_EXTERNALLY_VISIBLE);
-int kill_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int test_main(int argc, char **argv) USE_TEST(MAIN_EXTERNALLY_VISIBLE);
-#if ENABLE_ROUTE
+int kill_main(int argc, char **argv) USE_KILL(MAIN_EXTERNALLY_VISIBLE);
-void bb_displayroutes(int noresolve, int netstatfmt);
-#endif
 int chown_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-#if ENABLE_GUNZIP
 int gunzip_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-#endif
-#if ENABLE_BUNZIP2
 int bunzip2_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-#endif
 int bbunpack(char **argv,
 	char* (*make_new_name)(char *filename),
 	USE_DESKTOP(long long) int (*unpacker)(void)
 );
+#if ENABLE_ROUTE
+void bb_displayroutes(int noresolve, int netstatfmt);
+#endif
 
 
 /* Networking */

init/Config.in

@@ -98,13 +98,13 @@ config FEATURE_INITRD
 
 config HALT
 	bool "poweroff, halt, and reboot"
-	default y
+	default n
 	help
 	  Stop all processes and either halt, reboot, or power off the system.
 
 config MESG
 	bool "mesg"
-	default y
+	default n
 	help
 	  Mesg controls access to your terminal by others.  It is typically
 	  used to allow or disallow other users to write to your terminal

libbb/Kbuild

@@ -101,6 +101,7 @@ lib-y += wfopen_input.o
 lib-y += xatonum.o
 lib-y += xconnect.o
 lib-y += xfuncs.o
+lib-y += xfunc_die.o
 lib-y += xgetcwd.o
 lib-y += xgethostbyname.o
 lib-y += xreadlink.o

libbb/appletlib.c

@@ -36,6 +36,13 @@ static const char usage_messages[] ALIGN1 = ""
 
 /* Include generated applet names, pointers to <applet>_main, etc */
 #include "applet_tables.h"
+/* ...and if applet_tables generator says we have only one applet... */
+#ifdef SINGLE_APPLET_MAIN
+#undef ENABLE_FEATURE_INDIVIDUAL
+#define ENABLE_FEATURE_INDIVIDUAL 1
+#undef USE_FEATURE_INDIVIDUAL
+#define USE_FEATURE_INDIVIDUAL(...) __VA_ARGS__
+#endif
 
 
 #if ENABLE_FEATURE_COMPRESS_USAGE
@@ -77,6 +84,23 @@ static const char *unpack_usage_messages(void)
 void bb_show_usage(void)
 {
 	if (ENABLE_SHOW_USAGE) {
+#ifdef SINGLE_APPLET_STR
+		/* Imagine that this applet is "true". Dont suck in printf! */
+		const char *p;
+		const char *usage_string = p = unpack_usage_messages();
+
+		if (*p == '\b') {
+			write(2, "\nNo help available.\n\n",
+				sizeof("\nNo help available.\n\n") - 1);
+		} else {
+			write(2, "\nUsage: "SINGLE_APPLET_STR" ",
+				sizeof("\nUsage: "SINGLE_APPLET_STR" ") - 1);
+			write(2, p, strlen(p));
+			write(2, "\n\n", 2);
+		}
+		dealloc_usage_messages((char*)usage_string);
+#else
+// TODO: in this case, stdio is sucked in by busybox_main() anyway...
 		const char *format_string;
 		const char *p;
 		const char *usage_string = p = unpack_usage_messages();
@@ -84,18 +108,17 @@ void bb_show_usage(void)
 
 		if (ap < 0) /* never happens, paranoia */
 			xfunc_die();
-
 		while (ap) {
 			while (*p++) continue;
 			ap--;
 		}
-
 		fprintf(stderr, "%s multi-call binary\n", bb_banner);
 		format_string = "\nUsage: %s %s\n\n";
 		if (*p == '\b')
 			format_string = "\nNo help available.\n\n";
 		fprintf(stderr, format_string, applet_name, p);
 		dealloc_usage_messages((char*)usage_string);
+#endif
 	}
 	xfunc_die();
 }
@@ -123,6 +146,9 @@ int find_applet_by_name(const char *name)
 int *const bb_errno __attribute__ ((section (".data")));
 #endif
 
+void lbb_prepare(const char *applet
+		USE_FEATURE_INDIVIDUAL(, char **argv))
+				MAIN_EXTERNALLY_VISIBLE;
 void lbb_prepare(const char *applet
 		USE_FEATURE_INDIVIDUAL(, char **argv))
 {
@@ -158,6 +184,9 @@ const char *applet_name;
 bool re_execed;
 #endif
 
+
+#if !ENABLE_FEATURE_INDIVIDUAL
+
 USE_FEATURE_SUID(static uid_t ruid;)  /* real uid */
 
 #if ENABLE_FEATURE_SUID_CONFIG
@@ -660,6 +689,9 @@ void run_applet_and_exit(const char *name, char **argv)
 		exit(busybox_main(argv));
 }
 
+#endif /* !ENABLE_FEATURE_INDIVIDUAL */
+
+
 
 #if ENABLE_BUILD_LIBBUSYBOX
 int lbb_main(char **argv)
@@ -667,6 +699,11 @@ int lbb_main(char **argv)
 int main(int argc ATTRIBUTE_UNUSED, char **argv)
 #endif
 {
+#if ENABLE_FEATURE_INDIVIDUAL
+	/* Only one applet is selected by the user! */
+	lbb_prepare(SINGLE_APPLET_STR USE_FEATURE_INDIVIDUAL(, argv));
+	return SINGLE_APPLET_MAIN(argc, argv);
+#else
 	lbb_prepare("busybox" USE_FEATURE_INDIVIDUAL(, argv));
 
 #if !BB_MMU
@@ -685,4 +722,5 @@ int main(int argc ATTRIBUTE_UNUSED, char **argv)
 
 	run_applet_and_exit(applet_name, argv);
 	bb_error_msg_and_die("applet not found");
+#endif
 }

libbb/error_msg_and_die.c

@@ -9,33 +9,6 @@
 
 #include "libbb.h"
 
-int die_sleep;
-#if ENABLE_FEATURE_PREFER_APPLETS || ENABLE_HUSH
-jmp_buf die_jmp;
-#endif
-
-void xfunc_die(void)
-{
-	if (die_sleep) {
-		if ((ENABLE_FEATURE_PREFER_APPLETS || ENABLE_HUSH)
-		 && die_sleep < 0
-		) {
-			/* Special case. We arrive here if NOFORK applet
-			 * calls xfunc, which then decides to die.
-			 * We don't die, but jump instead back to caller.
-			 * NOFORK applets still cannot carelessly call xfuncs:
-			 * p = xmalloc(10);
-			 * q = xmalloc(10); // BUG! if this dies, we leak p!
-			 */
-			/* -2222 means "zero" (longjmp can't pass 0)
-			 * run_nofork_applet() catches -2222. */
-			longjmp(die_jmp, xfunc_error_retval ? xfunc_error_retval : -2222);
-		}
-		sleep(die_sleep);
-	}
-	exit(xfunc_error_retval);
-}
-
 void bb_error_msg_and_die(const char *s, ...)
 {
 	va_list p;

libbb/getopt32.c

@@ -285,6 +285,10 @@ const char *const bb_argv_dash[] = { "-", NULL };
 
 const char *opt_complementary;
 
+/* Many small applets don't want to suck in stdio.h only because
+ * they need to parse options by calling us */
+#define DONT_USE_PRINTF 1
+
 enum {
 	PARAM_STRING,
 	PARAM_LIST,
@@ -335,7 +339,8 @@ getopt32(char **argv, const char *applet_opts, ...)
 #define SHOW_USAGE_IF_ERROR     1
 #define ALL_ARGV_IS_OPTS        2
 #define FIRST_ARGV_IS_OPT       4
-#define FREE_FIRST_ARGV_IS_OPT  8
+#define FREE_FIRST_ARGV_IS_OPT  (8 * !DONT_USE_PRINTF)
+
 	int spec_flgs = 0;
 
 	argc = 0;
@@ -489,10 +494,16 @@ getopt32(char **argv, const char *applet_opts, ...)
 	va_end(p);
 
 	if (spec_flgs & FIRST_ARGV_IS_OPT) {
-		if (argv[1] && argv[1][0] != '-' && argv[1][0] != '\0') {
+		if (argv[1] && argv[1][0] != '-' && argv[1][1] != '\0') {
+#if DONT_USE_PRINTF
+			char *pp = alloca(strlen(argv[1]) + 2);
+			*pp++ = '-';
+			argv[1] = strcpy(pp, argv[1]);
+#else
 			argv[1] = xasprintf("-%s", argv[1]);
 			if (ENABLE_FEATURE_CLEAN_UP)
 				spec_flgs |= FREE_FIRST_ARGV_IS_OPT;
+#endif
 		}
 	}
 
@@ -573,7 +584,7 @@ getopt32(char **argv, const char *applet_opts, ...)
 		}
 	}
 
-#if (ENABLE_AR || ENABLE_TAR) && ENABLE_FEATURE_CLEAN_UP
+#if ENABLE_FEATURE_CLEAN_UP
 	if (spec_flgs & FREE_FIRST_ARGV_IS_OPT)
 		free(argv[1]);
 #endif

procps/kill.c

@@ -24,7 +24,6 @@
  * This is needed to avoid collision with kill -9 ... syntax
  */
 
-int kill_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int kill_main(int argc, char **argv)
 {
 	char *arg;

shell/Config.in

@@ -36,7 +36,6 @@ endchoice
 config ASH
 	bool "ash"
 	default n
-	select TEST
 	help
 	  Tha 'ash' shell adds about 60k in the default configuration and is
 	  the most complete and most pedantically correct shell included with
@@ -111,7 +110,6 @@ config ASH_GETOPTS
 config ASH_BUILTIN_ECHO
 	bool "Builtin version of 'echo'"
 	default y
-	select ECHO
 	depends on ASH
 	help
 	  Enable support for echo, builtin to ash.
@@ -119,7 +117,6 @@ config ASH_BUILTIN_ECHO
 config ASH_BUILTIN_TEST
 	bool "Builtin version of 'test'"
 	default y
-	select TEST
 	depends on ASH
 	help
 	  Enable support for test, builtin to ash.
@@ -170,10 +167,6 @@ config ASH_EXPAND_PRMT
 config HUSH
 	bool "hush"
 	default n
-	select TRUE
-	select FALSE
-	select TEST
-	select ECHO
 	help
 	  hush is a very small shell (just 18k) and it has fairly complete
 	  Bourne shell grammar.  It even handles all the normal flow control
@@ -240,13 +233,9 @@ config LASH
 	help
 	  lash is deprecated and will be removed, please migrate to hush.
 
-
 config MSH
 	bool "msh"
 	default n
-	select TRUE
-	select FALSE
-	select TEST
 	help
 	  The minix shell (adds just 30k) is quite complete and handles things
 	  like for/do/done, case/esac and all the things you expect a Bourne

shell/ash.c

@@ -8417,12 +8417,6 @@ returncmd(int argc ATTRIBUTE_UNUSED, char **argv)
 static int breakcmd(int, char **);
 static int dotcmd(int, char **);
 static int evalcmd(int, char **);
-#if ENABLE_ASH_BUILTIN_ECHO
-static int echocmd(int, char **);
-#endif
-#if ENABLE_ASH_BUILTIN_TEST
-static int testcmd(int, char **);
-#endif
 static int exitcmd(int, char **);
 static int exportcmd(int, char **);
 #if ENABLE_ASH_GETOPTS
@@ -8464,6 +8458,9 @@ static int ulimitcmd(int, char **);
  * Apart from the above, [[ expr ]] should work as [ expr ]
  */
 
+#define testcmd test_main
+#define echocmd echo_main
+
 /* Keep these in proper order since it is searched via bsearch() */
 static const struct builtincmd builtintab[] = {
 	{ BUILTIN_SPEC_REG      ".", dotcmd },
@@ -11506,22 +11503,6 @@ exitcmd(int argc ATTRIBUTE_UNUSED, char **argv)
 	/* NOTREACHED */
 }
 
-#if ENABLE_ASH_BUILTIN_ECHO
-static int
-echocmd(int argc, char **argv)
-{
-	return echo_main(argc, argv);
-}
-#endif
-
-#if ENABLE_ASH_BUILTIN_TEST
-static int
-testcmd(int argc, char **argv)
-{
-	return test_main(argc, argv);
-}
-#endif
-
 /*
  * Read a file containing shell functions.
  */