[BusyBox] Problems with ash exec

[Vladimir N. Oleynik]

Matt,
 
> When ash's exec command is used, it calls run_applet_by_name for
> each component in the path with the full pathname, until it finds
> the applet.  The first time it is called, it fails to find the
> applet (since it is specified with a full pathname), and resets
> recurse_level to 0.  On the next attempt, it falls back to
> busybox.  It bumps argv and tries to find the command, which
> fails, and it prints the usage message.
> 
> The least intrusive solution is to modify run_applet_by_name to
> decrement, rather than reset, recurse_level.

And as you concern to such addition of small convenience? 
It is required only 32 additional bytes. 
After this patch both variants will give identical result:

$ busybox --help applet
$ busybox applet --help
-------------- next part --------------
--- applets_orig.c	Sun Aug 26 21:00:47 2001
+++ applets.c	Sun Aug 26 21:07:13 2001
@@ -45,13 +45,6 @@
 	const char *format_string;
 	const char *usage_string = usage_messages;
 	int i;
-	/* From busybox.c */
-	extern int been_there_done_that;
-
-	if (strcmp(applet_using->name, "busybox")==0) {
-		been_there_done_that=1;
-		busybox_main(0, NULL);
-	}
 
 	for (i = applet_using - applets; i > 0; ) {
 		if (!*usage_string++) {
@@ -85,13 +78,23 @@
 void run_applet_by_name(const char *name, int argc, char **argv)
 {
 	static int recurse_level = 0;
+	extern int been_there_done_that; /* From busybox.c */
 
 	recurse_level++;
 	/* Do a binary search to find the applet entry given the name. */
 	if ((applet_using = find_applet_by_name(name)) != NULL) {
 		applet_name = applet_using->name;
 		if (argv[1] && strcmp(argv[1], "--help") == 0) {
-			show_usage();
+			if (strcmp(applet_using->name, "busybox")==0) {
+				if(argv[2])
+				  applet_using = find_applet_by_name(argv[2]);
+				 else
+				  applet_using = NULL;
+			}
+			if(applet_using)
+				show_usage();
+			been_there_done_that=1;
+			busybox_main(0, NULL);
 		}
 		exit((*(applet_using->main)) (argc, argv));
 	}
@@ -99,7 +102,7 @@
 	if (recurse_level == 1) {
 		run_applet_by_name("busybox", argc, argv);
 	}
-	recurse_level = 0;
+	recurse_level--;
 }