#include <stdio.h>
#include <stddef.h>

#define container_of(ptr, type, member) ({ \
	const typeof(((type*)0)->member)* __mptr = (ptr); \
	(type*)((char*)__mptr - offsetof(type, member)); })

// Minimal doubly linked list
struct list_head {
	struct list_head *next, *prev;
};

static inline void INIT_LIST_HEAD(struct list_head *list)
{
	list->next = list;
	list->prev = list;
}

static inline void __list_add(struct list_head *new, struct list_head *prev, struct list_head *next)
{
	next->prev = new;
	new->next = next;
	new->prev = prev;
	prev->next = new;
}

static inline void list_add(struct list_head *new, struct list_head *head)
{
	__list_add(new, head, head->next);
}

static inline void list_add_tail(struct list_head *new, struct list_head *head)
{
	__list_add(new, head->prev, head);
}

#define list_entry(ptr, type, member) \
	container_of(ptr, type, member)

#define list_for_each(pos, head) \
	for (pos = (head)->next; pos != (head); pos = pos->next)

// A small struct like the Linux kernel's task_struct
struct task_struct {
	int pid;
	const char *comm;
	struct list_head tasks; // linkage for global task list
} __attribute__((spslr));