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
  43 static inline void put_pid_ns(struct pid_namespace *ns)
  44 {
  45         if (ns != &init_pid_ns)
  46                 kref_put(&ns->kref, free_pid_ns);
  47 }
  48
  49 #else /* !CONFIG_PID_NS */
  50 #include <linux/err.h>
  51
  52 static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
  53 {
  54         return ns;
  55 }
  56
  57 static inline struct pid_namespace *
  58 copy_pid_ns(unsigned long flags, struct pid_namespace *ns)
  59 {
  60         if (flags & CLONE_NEWPID)
  61                 ns = ERR_PTR(-EINVAL);
  62         return ns;
  63 }
  64
  65 static inline void put_pid_ns(struct pid_namespace *ns)
  66 {
  67 }
  68
  69 #endif /* CONFIG_PID_NS */
  70
  71 static inline struct pid_namespace *task_active_pid_ns(struct task_struct *tsk)
  72 {
  73         return tsk->nsproxy->pid_ns;
  74 }
  75
  76 static inline struct task_struct *task_child_reaper(struct task_struct *tsk)
  77 {
  78         BUG_ON(tsk != current);
  79         return tsk->nsproxy->pid_ns->child_reaper;
  80 }
  81
  82 #endif /* _LINUX_PID_NS_H */