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 uid_gid_map      projid_map;
  24         struct kref             kref;
  25         struct user_namespace   *parent;
  26         kuid_t                  owner;
  27         kgid_t                  group;
  28 };
  29
  30 extern struct user_namespace init_user_ns;
  31
  32 #ifdef CONFIG_USER_NS
  33
  34 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  35 {
  36         if (ns)
  37                 kref_get(&ns->kref);
  38         return ns;
  39 }
  40
  41 extern int create_user_ns(struct cred *new);
  42 extern void free_user_ns(struct kref *kref);
  43
  44 static inline void put_user_ns(struct user_namespace *ns)
  45 {
  46         if (ns)
  47                 kref_put(&ns->kref, free_user_ns);
  48 }
  49
  50 struct seq_operations;
  51 extern struct seq_operations proc_uid_seq_operations;
  52 extern struct seq_operations proc_gid_seq_operations;
  53 extern struct seq_operations proc_projid_seq_operations;
  54 extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
  55 extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
  56 extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
  57 #else
  58
  59 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
  60 {
  61         return &init_user_ns;
  62 }
  63
  64 static inline int create_user_ns(struct cred *new)
  65 {
  66         return -EINVAL;
  67 }
  68
  69 static inline void put_user_ns(struct user_namespace *ns)
  70 {
  71 }
  72
  73 #endif
  74
  75 #endif /* _LINUX_USER_H */