LXR linux/include/linux/user

   1#ifndef _LINUX_USER_NAMESPACE_H
   2#define _LINUX_USER_NAMESPACE_H
   3
   4#include <linux/kref.h>
   5#include <linux/nsproxy.h>
   6#include <linux/sched.h>
   7#include <linux/err.h>
   8
   9#define UID_GID_MAP_MAX_EXTENTS 5
  10
  11struct uid_gid_map {    /* 64 bytes -- 1 cache line */
  12        u32 nr_extents;
  13        struct uid_gid_extent {
  14                u32 first;
  15                u32 lower_first;
  16                u32 count;
  17        } extent[UID_GID_MAP_MAX_EXTENTS];
  18};
  19
  20struct user_namespace {
  21        struct uid_gid_map      uid_map;
  22        struct uid_gid_map      gid_map;
  23        struct uid_gid_map      projid_map;
  24        atomic_t                count;
  25        struct user_namespace   *parent;
  26        int                     level;
  27        kuid_t                  owner;
  28        kgid_t                  group;
  29        unsigned int            proc_inum;
  30
  31        /* Register of per-UID persistent keyrings for this namespace */
  32#ifdef CONFIG_PERSISTENT_KEYRINGS
  33        struct key              *persistent_keyring_register;
  34        struct rw_semaphore     persistent_keyring_register_sem;
  35#endif
  36};
  37
  38extern struct user_namespace init_user_ns;
  39
  40#ifdef CONFIG_USER_NS
  41
  42static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  43{
  44        if (ns)
  45                atomic_inc(&ns->count);
  46        return ns;
  47}
  48
  49extern int create_user_ns(struct cred *new);
  50extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
  51extern void free_user_ns(struct user_namespace *ns);
  52
  53static inline void put_user_ns(struct user_namespace *ns)
  54{
  55        if (ns && atomic_dec_and_test(&ns->count))
  56                free_user_ns(ns);
  57}
  58
  59struct seq_operations;
  60extern struct seq_operations proc_uid_seq_operations;
  61extern struct seq_operations proc_gid_seq_operations;
  62extern struct seq_operations proc_projid_seq_operations;
  63extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
  64extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
  65extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
  66#else
  67
  68static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  69{
  70        return &init_user_ns;
  71}
  72
  73static inline int create_user_ns(struct cred *new)
  74{
  75        return -EINVAL;
  76}
  77
  78static inline int unshare_userns(unsigned long unshare_flags,
  79                                 struct cred **new_cred)
  80{
  81        if (unshare_flags & CLONE_NEWUSER)
  82                return -EINVAL;
  83        return 0;
  84}
  85
  86static inline void put_user_ns(struct user_namespace *ns)
  87{
  88}
  89
  90#endif
  91
  92#endif /* _LINUX_USER_H */
  93