Implement first instance of NOFORK applet - echo

find: use NOFORK/NOEXEC; small -exec buglet also eliminated
vfork_daemon_rexec: honor PREFER_APPLETS
echo: small size improvements

find -exec echo {} \; with PREFER_APPLETS=y runs 4 times faster

Config.in

@@ -244,7 +244,8 @@ config FEATURE_EXEC_PREFER_APPLETS
 	help
 	  This is an experimental option which directs applets about to
 	  call 'exec' to try and find an applicable busybox applet before
-	  searching the executable path for a binary or symlink to execute.
+	  searching the PATH. This may affect shell, find -exec, xargs and
+	  similar programs.
 
 config BUSYBOX_EXEC_PATH
 	string "Path to BusyBox executable"

coreutils/echo.c

@@ -20,86 +20,85 @@
  * 1) In handling '\c' escape, the previous version only suppressed the
  *     trailing newline.  SUSv3 specifies _no_ output after '\c'.
  * 2) SUSv3 specifies that octal escapes are of the form \0{#{#{#}}}.
- *    The previous version version did not allow 4-digit octals.
+ *    The previous version did not allow 4-digit octals.
  */
 
-
-#include <stdio.h>
-#include <string.h>
-#include <stdlib.h>
 #include "busybox.h"
 
 int bb_echo(char **argv)
 {
-#ifndef CONFIG_FEATURE_FANCY_ECHO
+	const char *arg;
+#if !ENABLE_FEATURE_FANCY_ECHO
 #define eflag '\\'
 	++argv;
 #else
 	const char *p;
-	int nflag = 1;
-	int eflag = 0;
+	char nflag = 1;
+	char eflag = 0;
+
+	while (1) {
+		arg = *++argv;
+		if (!arg)
+			goto ret;
+		if (*arg != '-')
+			break;
 
-	while (*++argv && (**argv == '-')) {
 		/* If it appears that we are handling options, then make sure
 		 * that all of the options specified are actually valid.
 		 * Otherwise, the string should just be echoed.
 		 */
-
-		if (!*(p = *argv + 1)) {	/* A single '-', so echo it. */
+		p = arg + 1;
+		if (!*p)	/* A single '-', so echo it. */
 			goto just_echo;
-		}
 
 		do {
-			if (strrchr("neE", *p) == 0) {
+			if (!strrchr("neE", *p))
 				goto just_echo;
-			}
 		} while (*++p);
 
 		/* All of the options in this arg are valid, so handle them. */
-		p = *argv + 1;
+		p = arg + 1;
 		do {
-			if (*p == 'n') {
+			if (*p == 'n')
 				nflag = 0;
-			} else if (*p == 'e') {
+			if (*p == 'e')
 				eflag = '\\';
-			} else {
-				eflag = 0;
-			}
 		} while (*++p);
 	}
-
-just_echo:
+ just_echo:
 #endif
-	while (*argv) {
+	while (1) {
+		/* arg is already = *argv and isn't NULL */
 		int c;
 
-		while ((c = *(*argv)++)) {
+		while ((c = *arg++)) {
 			if (c == eflag) {	/* Check for escape seq. */
-				if (**argv == 'c') {
+				if (*arg == 'c') {
 					/* '\c' means cancel newline and
 					 * ignore all subsequent chars. */
-					return 0;
+					goto ret;
 				}
-#ifndef CONFIG_FEATURE_FANCY_ECHO
+#if !ENABLE_FEATURE_FANCY_ECHO
 				/* SUSv3 specifies that octal escapes must begin with '0'. */
-				if (((unsigned int)(**argv - '1')) >= 7)
+				if ( (((unsigned char)*arg) - '1') >= 7)
 #endif
 				{
 					/* Since SUSv3 mandates a first digit of 0, 4-digit octals
 					* of the form \0### are accepted. */
-					if ((**argv == '0') && (((unsigned int)(argv[0][1] - '0')) < 8)) {
-						(*argv)++;
+					if (*arg == '0' && ((unsigned char)(arg[1]) - '0') < 8) {
+						arg++;
 					}
 					/* bb_process_escape_sequence can handle nul correctly */
-					c = bb_process_escape_sequence((const char **) argv);
+					c = bb_process_escape_sequence(&arg);
 				}
 			}
 			putchar(c);
 		}
 
-		if (*++argv) {
-			putchar(' ');
-		}
+		arg = *++argv;
+		if (!arg)
+			break;
+		putchar(' ');
 	}
 
 #ifdef CONFIG_FEATURE_FANCY_ECHO
@@ -109,14 +108,16 @@ just_echo:
 #else
 	putchar('\n');
 #endif
-	return 0;
+ ret:
+	return fflush(stdout);
 }
 
+/* This is a NOFORK applet. Be very careful! */
+
 int echo_main(int argc, char** argv);
 int echo_main(int argc, char** argv)
 {
-	(void)bb_echo(argv);
-	fflush_stdout_and_exit(EXIT_SUCCESS);
+	return bb_echo(argv);
 }
 
 /*-

findutils/find.c

@@ -242,9 +242,30 @@ ACTF(exec)
 	for (i = 0; i < ap->exec_argc; i++)
 		argv[i] = subst(ap->exec_argv[i], ap->subst_count[i], fileName);
 	argv[i] = NULL; /* terminate the list */
-	rc = wait4pid(spawn(argv));
-	if (rc)
+
+	if (ENABLE_FEATURE_EXEC_PREFER_APPLETS) {
+		const struct BB_applet *a = find_applet_by_name(argv[0]);
+		if (a) {
+			if (a->nofork) {
+				rc = a->main(ap->exec_argc, argv);
+				goto f;
+			}
+#ifndef BB_NOMMU
+			if (a->noexec) {
+				rc = fork();
+				if (rc) goto w;
+				current_applet = a;
+				run_current_applet_and_exit(ap->exec_argc, argv);
+			}
+#endif
+		}
+	}
+	rc = spawn(argv);
+ w:
+	rc = wait4pid(rc);
+	if (rc < 0)
 		bb_perror_msg("%s", argv[0]);
+ f:
 	for (i = 0; i < ap->exec_argc; i++)
 		free(argv[i]);
 	return rc == 0; /* return 1 if success */

include/applets.h

@@ -28,24 +28,28 @@ s     - suid type:
 # define APPLET_NOUSAGE(name,main,l,s)       int main##_main(int argc, char **argv);
 # define APPLET_ODDNAME(name,main,l,s,name2) int main##_main(int argc, char **argv);
 # define APPLET_NOEXEC(name,main,l,s,name2)  int main##_main(int argc, char **argv);
+# define APPLET_NOFORK(name,main,l,s,name2)  int main##_main(int argc, char **argv);
 
 #elif defined(MAKE_USAGE) && ENABLE_FEATURE_VERBOSE_USAGE
 # define APPLET(name,l,s)                    name##_trivial_usage "\n\n" name##_full_usage "\0"
 # define APPLET_NOUSAGE(name,main,l,s)       "\b\0"
 # define APPLET_ODDNAME(name,main,l,s,name2) name2##_trivial_usage "\n\n" name2##_full_usage "\0"
 # define APPLET_NOEXEC(name,main,l,s,name2)  name2##_trivial_usage "\n\n" name2##_full_usage "\0"
+# define APPLET_NOFORK(name,main,l,s,name2)  name2##_trivial_usage "\n\n" name2##_full_usage "\0"
 
 #elif defined(MAKE_USAGE) && !ENABLE_FEATURE_VERBOSE_USAGE
 # define APPLET(name,l,s)                    name##_trivial_usage "\0"
 # define APPLET_NOUSAGE(name,main,l,s)       "\b\0"
 # define APPLET_ODDNAME(name,main,l,s,name2) name2##_trivial_usage "\0"
 # define APPLET_NOEXEC(name,main,l,s,name2)  name2##_trivial_usage "\0"
+# define APPLET_NOFORK(name,main,l,s,name2)  name2##_trivial_usage "\0"
 
 #elif defined(MAKE_LINKS)
 # define APPLET(name,l,c)                    LINK l name
 # define APPLET_NOUSAGE(name,main,l,s)       LINK l name
 # define APPLET_ODDNAME(name,main,l,s,name2) LINK l name
 # define APPLET_NOEXEC(name,main,l,s,name2)  LINK l name
+# define APPLET_NOFORK(name,main,l,s,name2)  LINK l name
 
 #else
   const struct BB_applet applets[] = { /*    name,main,location,need_suid */
@@ -53,6 +57,7 @@ s     - suid type:
 # define APPLET_NOUSAGE(name,main,l,s)       {#name,main##_main,l,s},
 # define APPLET_ODDNAME(name,main,l,s,name2) {#name,main##_main,l,s},
 # define APPLET_NOEXEC(name,main,l,s,name2)  {#name,main##_main,l,s,1},
+# define APPLET_NOFORK(name,main,l,s,name2)  {#name,main##_main,l,s,1,1},
 #endif
 
 #if ENABLE_INSTALL_NO_USR
@@ -118,7 +123,7 @@ USE_DUMPKMAP(APPLET(dumpkmap, _BB_DIR_BIN, _BB_SUID_NEVER))
 USE_APP_DUMPLEASES(APPLET(dumpleases, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
 //USE_E2FSCK(APPLET(e2fsck, _BB_DIR_SBIN, _BB_SUID_NEVER))
 //USE_E2LABEL(APPLET_NOUSAGE(e2label, tune2fs, _BB_DIR_SBIN, _BB_SUID_NEVER))
-USE_ECHO(APPLET_NOEXEC(echo, echo, _BB_DIR_BIN, _BB_SUID_NEVER, echo))
+USE_ECHO(APPLET_NOFORK(echo, echo, _BB_DIR_BIN, _BB_SUID_NEVER, echo))
 USE_ED(APPLET(ed, _BB_DIR_BIN, _BB_SUID_NEVER))
 USE_FEATURE_GREP_EGREP_ALIAS(APPLET_NOUSAGE(egrep, grep, _BB_DIR_BIN, _BB_SUID_NEVER))
 USE_EJECT(APPLET(eject, _BB_DIR_USR_BIN, _BB_SUID_NEVER))

libbb/process_escape_sequence.c

@@ -8,9 +8,6 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include <stdio.h>
-#include <limits.h>
-#include <ctype.h>
 #include "libbb.h"
 
 #define WANT_HEX_ESCAPES 1
@@ -46,10 +43,10 @@ char bb_process_escape_sequence(const char **ptr)
 #endif
 
 	do {
-		d = (unsigned int)(*q - '0');
+		d = (unsigned char)(*q) - '0';
 #ifdef WANT_HEX_ESCAPES
 		if (d >= 10) {
-			d = ((unsigned int)(_tolower(*q) - 'a')) + 10;
+			d = (unsigned char)(_tolower(*q)) - 'a' + 10;
 		}
 #endif
 
@@ -80,7 +77,7 @@ char bb_process_escape_sequence(const char **ptr)
 				break;
 			}
 		} while (*++p);
-		n = *(p+(sizeof(charmap)/2));
+		n = *(p + (sizeof(charmap)/2));
 	}
 
 	*ptr = q;

libbb/vfork_daemon_rexec.c

@@ -26,14 +26,16 @@ pid_t spawn(char **argv)
 	volatile int failed;
 	pid_t pid;
 
-	// Be nice to nommu machines.
+// Ain't it a good place to fflush(NULL)?
+
+	/* Be nice to nommu machines. */
 	failed = 0;
 	pid = vfork();
 	if (pid < 0) /* error */
 		return pid;
 	if (!pid) { /* child */
-		/* Don't use BB_EXECVP tricks here! */
-		execvp(argv[0], argv);
+		/* This macro is ok - it doesn't do NOEXEC/NOFORK tricks */
+		BB_EXECVP(argv[0], argv);
 
 		/* We are (maybe) sharing a stack with blocked parent,
 		 * let parent know we failed and then exit to unblock parent