linux/include/linux/user_namespace.h
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   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        kuid_t                  owner;
  27        kgid_t                  group;
  28        unsigned int            proc_inum;
  29        bool                    may_mount_sysfs;
  30        bool                    may_mount_proc;
  31};
  32
  33extern struct user_namespace init_user_ns;
  34
  35#ifdef CONFIG_USER_NS
  36
  37static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  38{
  39        if (ns)
  40                atomic_inc(&ns->count);
  41        return ns;
  42}
  43
  44extern int create_user_ns(struct cred *new);
  45extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
  46extern void free_user_ns(struct user_namespace *ns);
  47
  48static inline void put_user_ns(struct user_namespace *ns)
  49{
  50        if (ns && atomic_dec_and_test(&ns->count))
  51                free_user_ns(ns);
  52}
  53
  54struct seq_operations;
  55extern struct seq_operations proc_uid_seq_operations;
  56extern struct seq_operations proc_gid_seq_operations;
  57extern struct seq_operations proc_projid_seq_operations;
  58extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
  59extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
  60extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
  61#else
  62
  63static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  64{
  65        return &init_user_ns;
  66}
  67
  68static inline int create_user_ns(struct cred *new)
  69{
  70        return -EINVAL;
  71}
  72
  73static inline int unshare_userns(unsigned long unshare_flags,
  74                                 struct cred **new_cred)
  75{
  76        if (unshare_flags & CLONE_NEWUSER)
  77                return -EINVAL;
  78        return 0;
  79}
  80
  81static inline void put_user_ns(struct user_namespace *ns)
  82{
  83}
  84
  85#endif
  86
  87void update_mnt_policy(struct user_namespace *userns);
  88
  89#endif /* _LINUX_USER_H */
  90
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