refactor to allow multiple hooks for one type

list.c

@@ -0,0 +1,66 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include "list.h"
+
+// simple linked list implementation
+
+struct list *list_new(void)
+{
+    return calloc(1, sizeof(struct list));
+}
+
+// removed linked list nodes but does not free their content
+void list_clear(struct list *list)
+{
+    struct list_item *next, *cur = list->head;
+    while (cur != NULL) {
+        next = cur->next;
+        free(cur);
+        cur = next;
+    }
+}
+
+// returns generated linked list node, or NULL on failure
+void *list_append(struct list *list, void *data)
+{
+    struct list_item *item = malloc(sizeof(struct list_item));
+    if (item == NULL) {
+        return NULL;
+    }
+    item->next = NULL;
+    item->data = data;
+    if (list->head == NULL) {
+        list->head = item;
+    } else {
+        list->tail->next = item;
+    }
+    list->tail = item;
+    return item;
+}
+
+// returns true if entry was removed, false otherwise
+bool list_remove(struct list *list, void *data)
+{
+    struct list_item *next, *cur, *prev = NULL;
+    // is list empty?
+    if (list->head == NULL) {
+        return false;
+    }
+    cur = list->head;
+    while (cur != NULL) {
+        next = cur->next;
+        if (cur->data == data) {
+            if (cur == list->head) {
+                list->head = next;
+            }
+            if (cur == list->tail) {
+                list->tail = prev;
+            }
+            free(cur);
+            return true;
+        }
+        prev = cur;
+        cur = next;
+    }
+    return false;
+}