xref: /linux-6.15/include/linux/pid_namespace.h (revision eb2bce7f)
1 #ifndef _LINUX_PID_NS_H
2 #define _LINUX_PID_NS_H
3 
4 #include <linux/sched.h>
5 #include <linux/mm.h>
6 #include <linux/threads.h>
7 #include <linux/pid.h>
8 #include <linux/nsproxy.h>
9 #include <linux/kref.h>
10 
11 struct pidmap {
12        atomic_t nr_free;
13        void *page;
14 };
15 
16 #define PIDMAP_ENTRIES         ((PID_MAX_LIMIT + 8*PAGE_SIZE - 1)/PAGE_SIZE/8)
17 
18 struct pid_namespace {
19 	struct kref kref;
20 	struct pidmap pidmap[PIDMAP_ENTRIES];
21 	int last_pid;
22 	struct task_struct *child_reaper;
23 };
24 
25 extern struct pid_namespace init_pid_ns;
26 
27 static inline void get_pid_ns(struct pid_namespace *ns)
28 {
29 	kref_get(&ns->kref);
30 }
31 
32 extern int copy_pid_ns(int flags, struct task_struct *tsk);
33 extern void free_pid_ns(struct kref *kref);
34 
35 static inline void put_pid_ns(struct pid_namespace *ns)
36 {
37 	kref_put(&ns->kref, free_pid_ns);
38 }
39 
40 static inline struct task_struct *child_reaper(struct task_struct *tsk)
41 {
42 	return init_pid_ns.child_reaper;
43 }
44 
45 #endif /* _LINUX_PID_NS_H */
46