83 lines
2.1 KiB
C
83 lines
2.1 KiB
C
// test_task_struct.c
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#include <stdio.h>
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#include <stddef.h> // for offsetof
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#define container_of(ptr, type, member) ({ \
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const typeof(((type*)0)->member)* __mptr = (ptr); \
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(type*)((char*)__mptr - offsetof(type, member)); })
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// Minimal doubly linked list
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struct list_head {
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struct list_head *next, *prev;
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};
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static inline void INIT_LIST_HEAD(struct list_head *list)
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{
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list->next = list;
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list->prev = list;
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}
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static inline void __list_add(struct list_head *new,
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struct list_head *prev,
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struct list_head *next)
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{
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next->prev = new;
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new->next = next;
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new->prev = prev;
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prev->next = new;
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}
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static inline void list_add(struct list_head *new, struct list_head *head)
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{
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__list_add(new, head, head->next);
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}
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static inline void list_add_tail(struct list_head *new, struct list_head *head)
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{
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__list_add(new, head->prev, head);
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}
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#define list_entry(ptr, type, member) \
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container_of(ptr, type, member)
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#define list_for_each(pos, head) \
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for (pos = (head)->next; pos != (head); pos = pos->next)
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// A small struct like the Linux kernel's task_struct
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struct task_struct {
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int pid;
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const char *comm;
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struct list_head tasks; // linkage for global task list
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} __attribute__((spslr));
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int main(void)
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{
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struct list_head task_list;
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INIT_LIST_HEAD(&task_list);
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struct task_struct t1 = { .pid = 1, .comm = "init" };
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struct task_struct t2 = { .pid = 2, .comm = "kthreadd" };
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struct task_struct t3 = { .pid = 3, .comm = "worker" };
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INIT_LIST_HEAD(&t1.tasks);
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INIT_LIST_HEAD(&t2.tasks);
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INIT_LIST_HEAD(&t3.tasks);
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list_add_tail(&t1.tasks, &task_list);
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list_add_tail(&t2.tasks, &task_list);
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list_add_tail(&t3.tasks, &task_list);
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printf("Task list:\n");
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struct list_head *pos;
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list_for_each(pos, &task_list) {
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struct task_struct *task = list_entry(pos, struct task_struct, tasks);
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printf(" pid=%d, comm=%s\n", task->pid, task->comm);
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}
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size_t myOffset = ((size_t)&((struct task_struct*)0)->tasks); // BROKEN, relevancy for kernel unknown
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return 0;
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}
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