*: kill bb_get_last_path_component, replace with two functions

(one which strips trailing slash and one which does not)
wget: straighten out as a result of above change
   text    data     bss     dec     hex filename
   5056       1       0    5057    13c1 busybox.t4/networking/wget.o
   5022       0       0    5022    139e busybox.t5/networking/wget.o

applets/applets.c

@@ -601,7 +601,7 @@ static int busybox_main(char **argv)
 	}
 	/* We support "busybox /a/path/to/applet args..." too. Allows for
 	 * "#!/bin/busybox"-style wrappers */
-	applet_name = bb_get_last_path_component(argv[0]);
+	applet_name = bb_get_last_path_component_nostrip(argv[0]);
 	run_applet_and_exit(applet_name, argv);
 	bb_error_msg_and_die("applet not found");
 }

coreutils/basename.c

@@ -34,7 +34,8 @@ int basename_main(int argc, char **argv)
 		bb_show_usage();
 	}
 
-	s = bb_get_last_path_component(*++argv);
+	/* It should strip slash: /abc/def/ -> def */
+	s = bb_get_last_path_component_strip(*++argv);
 
 	if (*++argv) {
 		n = strlen(*argv);

coreutils/cp.c

@@ -87,7 +87,7 @@ int cp_main(int argc, char **argv)
 	}
 
 	while (1) {
-		dest = concat_path_file(last, bb_get_last_path_component(*argv));
+		dest = concat_path_file(last, bb_get_last_path_component_strip(*argv));
  DO_COPY:
 		if (copy_file(*argv, dest, flags) < 0) {
 			status = 1;

coreutils/ln.c

@@ -45,7 +45,7 @@ int ln_main(int argc, char **argv)
 
 	if (argc == optind + 1) {
 		*--argv = last;
-		last = bb_get_last_path_component(xstrdup(last));
+		last = bb_get_last_path_component_strip(xstrdup(last));
 	}
 
 	do {
@@ -57,7 +57,7 @@ int ln_main(int argc, char **argv)
 		                NULL)
 		) {
 			src_name = xstrdup(*argv);
-			src = concat_path_file(src, bb_get_last_path_component(src_name));
+			src = concat_path_file(src, bb_get_last_path_component_strip(src_name));
 			free(src_name);
 			src_name = src;
 		}

coreutils/mv.c

@@ -68,7 +68,7 @@ int mv_main(int argc, char **argv)
 	}
 
 	do {
-		dest = concat_path_file(last, bb_get_last_path_component(*argv));
+		dest = concat_path_file(last, bb_get_last_path_component_strip(*argv));
 		dest_exists = cp_mv_stat(dest, &dest_stat);
 		if (dest_exists < 0) {
 			goto RET_1;

coreutils/rm.c

@@ -38,7 +38,7 @@ int rm_main(int argc, char **argv)
 
 	if (*argv != NULL) {
 		do {
-			const char *base = bb_get_last_path_component(*argv);
+			const char *base = bb_get_last_path_component_strip(*argv);
 
 			if (DOT_OR_DOTDOT(base)) {
 				bb_error_msg("cannot remove '.' or '..'");

include/libbb.h

@@ -236,9 +236,15 @@ extern void bb_copyfd_exact_size(int fd1, int fd2, off_t size);
 /* this helper yells "short read!" if param is not -1 */
 extern void complain_copyfd_and_die(off_t sz) ATTRIBUTE_NORETURN;
 extern char bb_process_escape_sequence(const char **ptr);
-/* TODO: sometimes modifies its parameter, which
- * makes it rather inconvenient at times: */
-extern char *bb_get_last_path_component(char *path);
+/* xxxx_strip version can modify its parameter:
+ * "/"        -> "/"
+ * "abc"      -> "abc"
+ * "abc/def"  -> "def"
+ * "abc/def/" -> "def" !!
+ */
+extern char *bb_get_last_path_component_strip(char *path);
+/* "abc/def/" -> "" and it never modifies 'path' */
+extern char *bb_get_last_path_component_nostrip(const char *path);
 
 int ndelay_on(int fd);
 int ndelay_off(int fd);

init/init.c

@@ -436,10 +436,11 @@ static pid_t run(const struct init_action *a)
 		++cmdpath;
 
 		/* find the last component in the command pathname */
-		s = bb_get_last_path_component(cmdpath);
+		s = bb_get_last_path_component_nostrip(cmdpath);
 
 		/* make a new argv[0] */
-		if ((cmd[0] = malloc(strlen(s) + 2)) == NULL) {
+		cmd[0] = malloc(strlen(s) + 2);
+		if (cmd[0] == NULL) {
 			message(L_LOG | L_CONSOLE, bb_msg_memory_exhausted);
 			cmd[0] = cmdpath;
 		} else {

libbb/get_last_path_component.c

@@ -8,25 +8,35 @@
  */
 
 #include "libbb.h"
-
-char *bb_get_last_path_component(char *path)
+/*
+ * "/"        -> "/"
+ * "abc"      -> "abc"
+ * "abc/def"  -> "def"
+ * "abc/def/" -> ""
+ */
+char *bb_get_last_path_component_nostrip(const char *path)
 {
-	char *first = path;
-	char *last;
+	char *slash = strrchr(path, '/');
 
-	last = path - 1;
+	if (!slash || (slash == path && !slash[1]))
+		return (char*)path;
 
-	while (*path) {
-		if ((*path != '/') && (path > ++last)) {
-			last = first = path;
-		}
-		++path;
-	}
-
-	if (*first == '/') {
-		last = first;
-	}
-	last[1] = '\0';
-
-	return first;
+	return slash + 1;
+}
+
+/*
+ * "/"        -> "/"
+ * "abc"      -> "abc"
+ * "abc/def"  -> "def"
+ * "abc/def/" -> "def" !!
+ */
+char *bb_get_last_path_component_strip(char *path)
+{
+	char *slash = last_char_is(path, '/');
+
+	if (slash)
+		while (*slash == '/' && slash != path)
+			*slash-- = '\0';
+
+	return bb_get_last_path_component_nostrip(path);
 }

libbb/run_shell.c

@@ -67,7 +67,7 @@ void run_shell(const char *shell, int loginshell, const char *command, const cha
 
 	args = xmalloc(sizeof(char*) * (4 + additional_args_cnt));
 
-	args[0] = bb_get_last_path_component(xstrdup(shell));
+	args[0] = bb_get_last_path_component_nostrip(xstrdup(shell));
 
 	if (loginshell)
 		args[0] = xasprintf("-%s", args[0]);

modutils/insmod.c

@@ -806,7 +806,7 @@ static int check_module_name_match(const char *filename, struct stat *statbuf,
 		return FALSE;
 	else {
 		char *tmp, *tmp1 = xstrdup(filename);
-		tmp = bb_get_last_path_component(tmp1);
+		tmp = bb_get_last_path_component_nostrip(tmp1);
 		if (strcmp(tmp, fullname) == 0) {
 			free(tmp1);
 			/* Stop searching if we find a match */

networking/wget.c

@@ -12,8 +12,8 @@
 struct host_info {
 	// May be used if we ever will want to free() all xstrdup()s...
 	/* char *allocated; */
-	char    *path;
-	char    *user;
+	const char *path;
+	const char *user;
 	char       *host;
 	int         port;
 	smallint    is_ftp;
@@ -318,9 +318,7 @@ static void parse_url(char *src_url, struct host_info *h)
 	p = strchr(h->host, '?'); if (!sp || (p && sp > p)) sp = p;
 	p = strchr(h->host, '#'); if (!sp || (p && sp > p)) sp = p;
 	if (!sp) {
-		/* must be writable because of bb_get_last_path_component() */
-		static char nullstr[] ALIGN1 = "";
-		h->path = nullstr;
+		h->path = "";
 	} else if (*sp == '/') {
 		*sp = '\0';
 		h->path = sp + 1;
@@ -328,7 +326,7 @@ static void parse_url(char *src_url, struct host_info *h)
 		// http://busybox.net?login=john@doe is a valid URL
 		// memmove converts to:
 		// http:/busybox.nett?login=john@doe...
-		memmove(h->host-1, h->host, sp - h->host);
+		memmove(h->host - 1, h->host, sp - h->host);
 		h->host--;
 		sp[-1] = '\0';
 		h->path = sp;
@@ -497,31 +495,20 @@ int wget_main(int argc, char **argv)
 		}
 	}
 
-	/* Guess an output filename */
+	/* Guess an output filename, if there was no -O FILE */
 	if (!fname_out) {
-		// Dirty hack. Needed because bb_get_last_path_component
-		// will destroy trailing / by storing '\0' in last byte!
-		if (!last_char_is(target.path, '/')) {
-			fname_out = bb_get_last_path_component(target.path);
-#if ENABLE_FEATURE_WGET_STATUSBAR
-			curfile = fname_out;
-#endif
-		}
-		if (!fname_out || !fname_out[0]) {
-			/* bb_get_last_path_component writes
-			 * to last '/' only. We don't have one here... */
+		fname_out = bb_get_last_path_component_nostrip(target.path);
+		/* handle "wget http://kernel.org//" */
+		if (fname_out[0] == '/' || !fname_out[0])
 			fname_out = (char*)"index.html";
-#if ENABLE_FEATURE_WGET_STATUSBAR
-			curfile = fname_out;
-#endif
-		}
-		if (dir_prefix != NULL)
+		/* -P DIR is considered only if there was no -O FILE */
+		if (dir_prefix)
 			fname_out = concat_path_file(dir_prefix, fname_out);
-#if ENABLE_FEATURE_WGET_STATUSBAR
-	} else {
-		curfile = bb_get_last_path_component(fname_out);
-#endif
 	}
+#if ENABLE_FEATURE_WGET_STATUSBAR
+	curfile = bb_get_last_path_component_nostrip(fname_out);
+#endif
+
 	/* Impossible?
 	if ((opt & WGET_OPT_CONTINUE) && !fname_out)
 		bb_error_msg_and_die("cannot specify continue (-c) without a filename (-O)"); */

shell/lash.c

@@ -1141,12 +1141,11 @@ static int pseudo_exec(struct child_prog *child)
 		}
 	}
 
-
 	/* Check if the command matches any busybox internal
 	 * commands ("applets") here.  Following discussions from
 	 * November 2000 on busybox@busybox.net, don't use
-	 * bb_get_last_path_component().  This way explicit (with
-	 * slashes) filenames will never be interpreted as an
+	 * bb_get_last_path_component_nostrip().  This way explicit
+	 * (with slashes) filenames will never be interpreted as an
 	 * applet, just like with builtins.  This way the user can
 	 * override an applet with an explicit filename reference.
 	 * The only downside to this change is that an explicit