#include <spslr.h>

#include "task_struct.h"

int second_pid();
const char* second_comm();
int subsecond_pid();
const char* subsecond_comm();

struct task_struct global = { .pid = 42, .comm = "main_global" };

static void print_layout() {
    // TODO -> Make builtin __spslr_initial_offsetof(type, field) that is not patched
    printf("Current task_struct layout:\n");
    printf("    stuck0 (int)             : %2llu -> %2llu\n", 0, offsetof(struct task_struct, stuck0));
    printf("    pid (int)                : %2llu -> %2llu\n", 8, offsetof(struct task_struct, pid));
    printf("    comm (const char*)       : %2llu -> %2llu\n", 16, offsetof(struct task_struct, comm));
    printf("    tasks (struct list_head) : %2llu -> %2llu\n", 24, offsetof(struct task_struct, tasks));
    printf("    stuck1 (int)             : %2llu -> %2llu\n", 40, offsetof(struct task_struct, stuck1));
    printf("    stuck2 (int)             : %2llu -> %2llu\n", 44, offsetof(struct task_struct, stuck2));
}

int main(void)
{
    spslr_selfpatch();
    print_layout();

    struct list_head task_list;
    INIT_LIST_HEAD(&task_list);

    struct task_struct t1 = { .pid = 1, .comm = "init" };
    struct task_struct t2 = { .pid = 2, .comm = "kthreadd" };
    struct task_struct t3 = { .pid = 3, .comm = "worker" };

    INIT_LIST_HEAD(&t1.tasks);
    INIT_LIST_HEAD(&t2.tasks);
    INIT_LIST_HEAD(&t3.tasks);

    list_add_tail(&t1.tasks, &task_list);
    list_add_tail(&t2.tasks, &task_list);
    list_add_tail(&t3.tasks, &task_list);

    printf("Task list:\n");

    struct list_head *pos;
    list_for_each(pos, &task_list) {
        struct task_struct *task = list_entry(pos, struct task_struct, tasks);
        printf("  pid=%d, comm=%s\n", task->pid, task->comm);
    }

    size_t myOffset = ((size_t)&((struct task_struct*)0)->tasks);
    printf("DIY offsetof(task_struct, tasks) yiels %2llu\n", myOffset);

    printf("Global: pid=%d comm=\"%s\"\n", global.pid, global.comm);
    printf("Second global: pid=%d comm=\"%s\"\n", second_pid(), second_comm());
    printf("Subsecond global: pid=%d comm=\"%s\"\n", subsecond_pid(), subsecond_comm());

    return 0;
}