include/linux/pid_namespace.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_PID_NS_H
   3 #define _LINUX_PID_NS_H
   4
   5 #include <linux/sched.h>
   6 #include <linux/bug.h>
   7 #include <linux/mm.h>
   8 #include <linux/workqueue.h>
   9 #include <linux/threads.h>
  10 #include <linux/nsproxy.h>
  11 #include <linux/kref.h>
  12 #include <linux/ns_common.h>
  13
  14 struct pidmap {
  15        atomic_t nr_free;
  16        void *page;
  17 };
  18
  19 #define BITS_PER_PAGE           (PAGE_SIZE * 8)
  20 #define BITS_PER_PAGE_MASK      (BITS_PER_PAGE-1)
  21 #define PIDMAP_ENTRIES          ((PID_MAX_LIMIT+BITS_PER_PAGE-1)/BITS_PER_PAGE)
  22
  23 struct fs_pin;
  24
  25 enum { /* definitions for pid_namespace's hide_pid field */
  26         HIDEPID_OFF       = 0,
  27         HIDEPID_NO_ACCESS = 1,
  28         HIDEPID_INVISIBLE = 2,
  29 };
  30
  31 struct pid_namespace {
  32         struct kref kref;
  33         struct pidmap pidmap[PIDMAP_ENTRIES];
  34         struct rcu_head rcu;
  35         int last_pid;
  36         unsigned int nr_hashed;
  37         struct task_struct *child_reaper;
  38         struct kmem_cache *pid_cachep;
  39         unsigned int level;
  40         struct pid_namespace *parent;
  41 #ifdef CONFIG_PROC_FS
  42         struct vfsmount *proc_mnt;
  43         struct dentry *proc_self;
  44         struct dentry *proc_thread_self;
  45 #endif
  46 #ifdef CONFIG_BSD_PROCESS_ACCT
  47         struct fs_pin *bacct;
  48 #endif
  49         struct user_namespace *user_ns;
  50         struct ucounts *ucounts;
  51         struct work_struct proc_work;
  52         kgid_t pid_gid;
  53         int hide_pid;
  54         int reboot;     /* group exit code if this pidns was rebooted */
  55         struct ns_common ns;
  56 } __randomize_layout;
  57
  58 extern struct pid_namespace init_pid_ns;
  59
  60 #define PIDNS_HASH_ADDING (1U << 31)
  61
  62 #ifdef CONFIG_PID_NS
  63 static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
  64 {
  65         if (ns != &init_pid_ns)
  66                 kref_get(&ns->kref);
  67         return ns;
  68 }
  69
  70 extern struct pid_namespace *copy_pid_ns(unsigned long flags,
  71         struct user_namespace *user_ns, struct pid_namespace *ns);
  72 extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);
  73 extern int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd);
  74 extern void put_pid_ns(struct pid_namespace *ns);
  75
  76 #else /* !CONFIG_PID_NS */
  77 #include <linux/err.h>
  78
  79 static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
  80 {
  81         return ns;
  82 }
  83
  84 static inline struct pid_namespace *copy_pid_ns(unsigned long flags,
  85         struct user_namespace *user_ns, struct pid_namespace *ns)
  86 {
  87         if (flags & CLONE_NEWPID)
  88                 ns = ERR_PTR(-EINVAL);
  89         return ns;
  90 }
  91
  92 static inline void put_pid_ns(struct pid_namespace *ns)
  93 {
  94 }
  95
  96 static inline void zap_pid_ns_processes(struct pid_namespace *ns)
  97 {
  98         BUG();
  99 }
 100
 101 static inline int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
 102 {
 103         return 0;
 104 }
 105 #endif /* CONFIG_PID_NS */
 106
 107 extern struct pid_namespace *task_active_pid_ns(struct task_struct *tsk);
 108 void pidhash_init(void);
 109 void pidmap_init(void);
 110
 111 #endif /* _LINUX_PID_NS_H */