Use strncpy instead of memcpy for safer access

queue.c

@@ -53,14 +53,11 @@ element_t *q_new_element(char *s)
     element_t *new = malloc(sizeof(element_t));
     if (!new)
         return NULL;
-    unsigned int size = str_len(s);
-    new->value = malloc(size + 1);
+    new->value = strdup(s);
     if (!new->value) {
         free(new);
         return NULL;
     }
-    memcpy(new->value, s, size);
-    *(new->value + size) = '\0';
     return new;
 }
 
@@ -96,9 +93,11 @@ element_t *q_remove(struct list_head *head, char *sp, size_t bufsize)
     if (!head)
         return NULL;
     element_t *ret = list_entry(head, element_t, list);
+    if (!ret)
+        return NULL;
     list_del(head);
-    if (ret && sp && bufsize > 0) {
-        memcpy(sp, ret->value, bufsize - 1);
+    if (sp && bufsize - 1 > 0) {
+        strncpy(sp, ret->value, bufsize - 1);
         *(sp + bufsize - 1) = '\0';
     }
     return ret;
@@ -199,8 +198,7 @@ void q_reverseK(struct list_head *head, int k)
     LIST_HEAD(tmp);
     int count = 0;
     list_for_each_safe (cur, n, head) {
-        list_del(cur);
-        list_add(cur, &tmp);
+        list_move(cur, &tmp);
         ++count;
         if (count == k) {
             count = 0;