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include/linux/projid.h 2.22 KB
d7d243b52   Eric Lee   SMARC-iMX8MQ Linu...
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  /* SPDX-License-Identifier: GPL-2.0 */
  #ifndef _LINUX_PROJID_H
  #define _LINUX_PROJID_H
  
  /*
   * A set of types for the internal kernel types representing project ids.
   *
   * The types defined in this header allow distinguishing which project ids in
   * the kernel are values used by userspace and which project id values are
   * the internal kernel values.  With the addition of user namespaces the values
   * can be different.  Using the type system makes it possible for the compiler
   * to detect when we overlook these differences.
   *
   */
  #include <linux/types.h>
  
  struct user_namespace;
  extern struct user_namespace init_user_ns;
  
  typedef __kernel_uid32_t projid_t;
  
  typedef struct {
  	projid_t val;
  } kprojid_t;
  
  static inline projid_t __kprojid_val(kprojid_t projid)
  {
  	return projid.val;
  }
  
  #define KPROJIDT_INIT(value) (kprojid_t){ value }
  
  #define INVALID_PROJID KPROJIDT_INIT(-1)
  #define OVERFLOW_PROJID 65534
  
  static inline bool projid_eq(kprojid_t left, kprojid_t right)
  {
  	return __kprojid_val(left) == __kprojid_val(right);
  }
  
  static inline bool projid_lt(kprojid_t left, kprojid_t right)
  {
  	return __kprojid_val(left) < __kprojid_val(right);
  }
  
  static inline bool projid_valid(kprojid_t projid)
  {
  	return !projid_eq(projid, INVALID_PROJID);
  }
  
  #ifdef CONFIG_USER_NS
  
  extern kprojid_t make_kprojid(struct user_namespace *from, projid_t projid);
  
  extern projid_t from_kprojid(struct user_namespace *to, kprojid_t projid);
  extern projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t projid);
  
  static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
  {
  	return from_kprojid(ns, projid) != (projid_t)-1;
  }
  
  #else
  
  static inline kprojid_t make_kprojid(struct user_namespace *from, projid_t projid)
  {
  	return KPROJIDT_INIT(projid);
  }
  
  static inline projid_t from_kprojid(struct user_namespace *to, kprojid_t kprojid)
  {
  	return __kprojid_val(kprojid);
  }
  
  static inline projid_t from_kprojid_munged(struct user_namespace *to, kprojid_t kprojid)
  {
  	projid_t projid = from_kprojid(to, kprojid);
  	if (projid == (projid_t)-1)
  		projid = OVERFLOW_PROJID;
  	return projid;
  }
  
  static inline bool kprojid_has_mapping(struct user_namespace *ns, kprojid_t projid)
  {
  	return true;
  }
  
  #endif /* CONFIG_USER_NS */
  
  #endif /* _LINUX_PROJID_H */