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

1 files changed, 38 insertions, 37 deletions

diff --git a/coreutils/echo.c b/coreutils/echo.c
index 8270fc006..486245508 100644
--- a/coreutils/echo.c
+++ b/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);
 }
 
 /*-