Commit Vladimir's simplify_path.

libbb/simplify_path.c

@@ -0,0 +1,78 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * simplify_path implementation for busybox
+ *
+ *
+ * Copyright (C) 2001  Vladimir N. Oleynik <dzo@simtreas.ru>
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <stdlib.h>
+
+#include "libbb.h"
+
+static inline char *strcpy_overlap(char *dst, const char *src)
+{
+	char *ptr = dst;
+
+	do *dst++ = *src; while (*src++);
+	return ptr;
+}
+
+char *simplify_path(const char *path)
+{
+	char *s, *start, *next;
+
+	if (path[0] == '/')
+	       start = xstrdup(path);
+	else {
+	       s = xgetcwd(NULL);
+	       start = concat_path_file(s, path);
+	       free(s);
+	}
+	s = start;
+	/* remove . and .. */
+	while(*s) {
+		if(*s++ == '/' && (*s == '/' || *s == 0)) {
+			/* remove duplicate and trailing slashes */
+			s = strcpy_overlap(s-1, s);
+		}
+		else if(*(s-1) == '.' && *(s-2)=='/') {
+			if(*s == '/' || *s == 0) {
+				/* remove . */
+				s = strcpy_overlap(s-1, s); /* maybe set // */
+				s--;
+			} else if(*s == '.') {
+				next = s+1;     /* set after ".." */
+				if(*next == '/' || *next == 0) {  /* "../" */
+					if((s-=2) > start)
+						/* skip previous dir */
+						do s--; while(*s != '/');
+					/* remove previous dir */
+					strcpy_overlap(s, next);
+				}
+
+			}
+		}
+	}
+	if(start[0]==0) {
+		start[0]='/';
+		start[1]=0;
+	}
+	return start;
+}