include/linux/user_namespace.h

   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
  11 struct 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
  20 struct user_namespace {
  21         struct uid_gid_map      uid_map;
  22         struct uid_gid_map      gid_map;
  23         struct kref             kref;
  24         struct user_namespace   *parent;
  25         kuid_t                  owner;
  26         kgid_t                  group;
  27 };
  28
  29 extern struct user_namespace init_user_ns;
  30
  31 #ifdef CONFIG_USER_NS
  32
  33 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  34 {
  35         if (ns)
  36                 kref_get(&ns->kref);
  37         return ns;
  38 }
  39
  40 extern int create_user_ns(struct cred *new);
  41 extern void free_user_ns(struct kref *kref);
  42
  43 static inline void put_user_ns(struct user_namespace *ns)
  44 {
  45         if (ns)
  46                 kref_put(&ns->kref, free_user_ns);
  47 }
  48
  49 struct seq_operations;
  50 extern struct seq_operations proc_uid_seq_operations;
  51 extern struct seq_operations proc_gid_seq_operations;
  52 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
  53 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
  54 #else
  55
  56 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  57 {
  58         return &init_user_ns;
  59 }
  60
  61 static inline int create_user_ns(struct cred *new)
  62 {
  63         return -EINVAL;
  64 }
  65
  66 static inline void put_user_ns(struct user_namespace *ns)
  67 {
  68 }
  69
  70 #endif
  71
  72 #endif /* _LINUX_USER_H */