diff --git a/include/r3_str.h b/include/r3_str.h
index f4d585e..9750cd1 100644
--- a/include/r3_str.h
+++ b/include/r3_str.h
@@ -28,6 +28,10 @@ void str_repeat(char *s, char *c, int len);
 
 void print_indent(int level);
 
+char *my_strdup(const char *s);
+
+char *my_strndup(const char *s, size_t n);
+
 
 #endif /* !STR_H */
 
diff --git a/src/edge.c b/src/edge.c
index a1b4e72..cccd531 100644
--- a/src/edge.c
+++ b/src/edge.c
@@ -41,7 +41,7 @@ void r3_edge_branch(edge *e, int dl) {
     // the suffix edge of the leaf
     c1 = r3_tree_create(3);
     s1_len = e->pattern_len - dl;
-    e1 = r3_edge_create(strndup(s1, s1_len), s1_len, c1);
+    e1 = r3_edge_create(my_strndup(s1, s1_len), s1_len, c1);
     // printf("edge left: %s\n", e1->pattern);
 
     // Migrate the child edges to the new edge we just created.
diff --git a/src/node.c b/src/node.c
index 02caa39..100bd0e 100644
--- a/src/node.c
+++ b/src/node.c
@@ -274,7 +274,7 @@ node * r3_tree_match(node * n, char * path, int path_len, match_entry * entry) {
 
                 if (entry && e->has_slug) {
                     // append captured token to entry
-                    str_array_append(entry->vars , strndup(substring_start, substring_length));
+                    str_array_append(entry->vars , my_strndup(substring_start, substring_length));
                 }
                 if (restlen == 0) {
                     return e->child;
@@ -378,7 +378,7 @@ node * r3_tree_insert_pathn(node *tree, char *route, int route_len, void * route
     if ( dl == 0 ) {
         // not found, we should just insert a whole new edge
         node * child = r3_tree_create(3);
-        r3_tree_add_child(n, strndup(route, route_len) , child);
+        r3_tree_add_child(n, my_strndup(route, route_len) , child);
         info("edge not found, insert one: %s\n", route);
         child->route_ptr = route_ptr;
         child->endpoint++;
@@ -415,13 +415,13 @@ node * r3_tree_insert_pathn(node *tree, char *route, int route_len, void * route
         // here is the new edge from.
         c2 = r3_tree_create(3);
         s2_len = route_len - dl;
-        e2 = r3_edge_create(strndup(s2, s2_len), s2_len, c2);
+        e2 = r3_edge_create(my_strndup(s2, s2_len), s2_len, c2);
         // printf("edge right: %s\n", e2->pattern);
         r3_tree_append_edge(e->child, e2);
 
         // truncate the original edge pattern 
         free(e->pattern);
-        e->pattern = strndup(e->pattern, dl);
+        e->pattern = my_strndup(e->pattern, dl);
         e->pattern_len = dl;
 
         // move n->edges to c1
diff --git a/src/str.c b/src/str.c
index ca86b17..5d0caf8 100644
--- a/src/str.c
+++ b/src/str.c
@@ -62,7 +62,7 @@ char * compile_slug(char * str, int len)
     s1 = strchr(str, '{');
 
     if ( s1 == NULL ) {
-        return strdup(str);
+        return my_strdup(str);
     }
 
     if ( (s1 - str) > 0 ) {
@@ -117,7 +117,7 @@ char * ltrim_slash(char* str)
 {
     char * p = str;
     while (*p == '/') p++;
-    return strdup(p);
+    return my_strdup(p);
 }
 
 char** str_split(char* a_str, const char a_delim)
@@ -158,7 +158,7 @@ char** str_split(char* a_str, const char a_delim)
         while (token)
         {
             assert(idx < count);
-            *(result + idx++) = strdup(token);
+            *(result + idx++) = my_strdup(token);
             token = strtok(0, delim);
         }
         assert(idx == count - 1);
@@ -180,3 +180,29 @@ void print_indent(int level) {
         printf(" ");
     }
 }
+
+char *my_strdup(const char *s) {
+    char *out;
+    size_t count = 0;
+    while( s[count] )
+        ++count;
+    ++count;
+    out = malloc(sizeof(char*) * count);
+    out[--count] = 0;
+    while( --count >= 0 )
+        out[count] = s[count];
+    return out;
+}
+
+char *my_strndup(const char *s, size_t n) {
+    char *out;
+    size_t count = 0;
+    while( count < n && s[count] )
+        ++count;
+    ++count;
+    out = malloc(sizeof(char*) * count);
+    out[--count] = 0;
+    while( --count >= 0 )
+        out[count] = s[count];
+    return out;
+}
diff --git a/src/token.c b/src/token.c
index 45ff273..fd47fe9 100644
--- a/src/token.c
+++ b/src/token.c
@@ -96,21 +96,21 @@ str_array * split_route_pattern(char *pattern, int pattern_len) {
                 assert(p - pattern < pattern_len ); // throw exception
             }
             p++; // contains the '}'
-            // printf("==> %s\n", strndup(s1, p-s1) );
-            str_array_append(str_array, strndup(s1, p-s1) );
+            // printf("==> %s\n", my_strndup(s1, p-s1) );
+            str_array_append(str_array, my_strndup(s1, p-s1) );
             s1 = p;
             continue;
         }
         else if ( *p == '/' ) {
-            // printf("==> %s\n", strndup(s1, p-s1) );
-            str_array_append(str_array, strndup(s1, p-s1) );
+            // printf("==> %s\n", my_strndup(s1, p-s1) );
+            str_array_append(str_array, my_strndup(s1, p-s1) );
             s1 = p;
         }
         p++;
     }
 
     if ( p-s1 > 0 ) {
-        str_array_append(str_array, strndup(s1, p-s1) );
+        str_array_append(str_array, my_strndup(s1, p-s1) );
     }
     return str_array;
 }