Backport Manuel Novoa III's rewrite to the stable branch

diff --git a/busybox/libbb/simplify_path.c b/busybox/libbb/simplify_path.c
index 4641bae88368988aa32f9a45babbd38a408309be..cf5b838a1201dbd272c71a6506de5e09e9782f61 100644 (file)
--- a/busybox/libbb/simplify_path.c
+++ b/busybox/libbb/simplify_path.c
@@ -3,7 +3,7 @@
  * simplify_path implementation for busybox
  *
  *
- * Copyright (C) 2001  Vladimir N. Oleynik <dzo@simtreas.ru>
+ * Copyright (C) 2001  Manuel Novoa III  <mjn3@opensource.lineo.com>
  *
  *
  * This program is free software; you can redistribute it and/or modify
@@ -26,53 +26,42 @@
 
 #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;
+       char *s, *start, *p;
 
        if (path[0] == '/')
-              start = xstrdup(path);
+               start = xstrdup(path);
        else {
-              s = xgetcwd(NULL);
-              start = concat_path_file(s, path);
-              free(s);
+               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);
-                               }
+       p = s = start;
 
+       do {
+               if (*p == '/') {
+                       if (*s == '/') {        /* skip duplicate (or initial) slash */
+                               continue;
+                       } else if (*s == '.') {
+                               if (s[1] == '/' || s[1] == 0) { /* remove extra '.' */
+                                       continue;
+                               } else if ((s[1] == '.') && (s[2] == '/' || s[2] == 0)) {
+                                       ++s;
+                                       if (p > start) {
+                                               while (*--p != '/');    /* omit previous dir */
+                                       }
+                                       continue;
+                               }
                        }
                }
+               *++p = *s;
+       } while (*++s);
+
+       if ((p == start) || (*p != '/')) {      /* not a trailing slash */
+               ++p;                                    /* so keep last character */
        }
-       if(start[0]==0) {
-               start[0]='/';
-               start[1]=0;
-       }
+       *p = 0;
+
        return start;
 }