include/linux/pid_namespace.h

   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/nsproxy.h>
   8 #include <linux/kref.h>
   9
  10 struct pidmap {
  11        atomic_t nr_free;
  12        void *page;
  13 };
  14
  15 #define PIDMAP_ENTRIES         ((PID_MAX_LIMIT + 8*PAGE_SIZE - 1)/PAGE_SIZE/8)
  16
  17 struct pid_namespace {
  18         struct kref kref;
  19         struct pidmap pidmap[PIDMAP_ENTRIES];
  20         int last_pid;
  21         struct task_struct *child_reaper;
  22         struct kmem_cache *pid_cachep;
  23         int level;
  24         struct pid_namespace *parent;
  25 #ifdef CONFIG_PROC_FS
  26         struct vfsmount *proc_mnt;
  27 #endif
  28 };
  29
  30 extern struct pid_namespace init_pid_ns;
  31
  32 #ifdef CONFIG_PID_NS
  33 static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
  34 {
  35         if (ns != &init_pid_ns)
  36                 kref_get(&ns->kref);
  37         return ns;
  38 }
  39
  40 extern struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *ns);
  41 extern void free_pid_ns(struct kref *kref);
  42 extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);
  43
  44 static inline void put_pid_ns(struct pid_namespace *ns)
  45 {
  46         if (ns != &init_pid_ns)
  47                 kref_put(&ns->kref, free_pid_ns);
  48 }
  49
  50 #else /* !CONFIG_PID_NS */
  51 #include <linux/err.h>
  52
  53 static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
  54 {
  55         return ns;
  56 }
  57
  58 static inline struct pid_namespace *
  59 copy_pid_ns(unsigned long flags, struct pid_namespace *ns)
  60 {
  61         if (flags & CLONE_NEWPID)
  62                 ns = ERR_PTR(-EINVAL);
  63         return ns;
  64 }
  65
  66 static inline void put_pid_ns(struct pid_namespace *ns)
  67 {
  68 }
  69
  70
  71 static inline void zap_pid_ns_processes(struct pid_namespace *ns)
  72 {
  73         BUG();
  74 }
  75 #endif /* CONFIG_PID_NS */
  76
  77 static inline struct pid_namespace *task_active_pid_ns(struct task_struct *tsk)
  78 {
  79         return tsk->nsproxy->pid_ns;
  80 }
  81
  82 static inline struct task_struct *task_child_reaper(struct task_struct *tsk)
  83 {
  84         BUG_ON(tsk != current);
  85         return tsk->nsproxy->pid_ns->child_reaper;
  86 }
  87
  88 #endif /* _LINUX_PID_NS_H */