/* SPDX-License-Identifier: GPL-2.0 */

  /*
   * linux/ipc/util.h
   * Copyright (C) 1999 Christoph Rohland
   *

   * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>

   * namespaces support.      2006 OpenVZ, SWsoft Inc.
   *                               Pavel Emelianov <xemul@openvz.org>

   */
  
  #ifndef _IPC_UTIL_H
  #define _IPC_UTIL_H

  #include <linux/unistd.h>

  #include <linux/err.h>

  #include <linux/ipc_namespace.h>

  /*
   * The IPC ID contains 2 separate numbers - index and sequence number.
   * By default,
   *   bits  0-14: index (32k, 15 bits)
   *   bits 15-30: sequence number (64k, 16 bits)
   *
   * When IPCMNI extension mode is turned on, the composition changes:
   *   bits  0-23: index (16M, 24 bits)
   *   bits 24-30: sequence number (128, 7 bits)
   */
  #define IPCMNI_SHIFT		15
  #define IPCMNI_EXTEND_SHIFT	24

  #define IPCMNI_EXTEND_MIN_CYCLE	(RADIX_TREE_MAP_SIZE * RADIX_TREE_MAP_SIZE)

  #define IPCMNI			(1 << IPCMNI_SHIFT)
  #define IPCMNI_EXTEND		(1 << IPCMNI_EXTEND_SHIFT)
  
  #ifdef CONFIG_SYSVIPC_SYSCTL
  extern int ipc_mni;
  extern int ipc_mni_shift;

  extern int ipc_min_cycle;

  #define ipcmni_seq_shift()	ipc_mni_shift

  #define IPCMNI_IDX_MASK		((1 << ipc_mni_shift) - 1)
  
  #else /* CONFIG_SYSVIPC_SYSCTL */
  
  #define ipc_mni			IPCMNI

  #define ipc_min_cycle		((int)RADIX_TREE_MAP_SIZE)

  #define ipcmni_seq_shift()	IPCMNI_SHIFT

  #define IPCMNI_IDX_MASK		((1 << IPCMNI_SHIFT) - 1)
  #endif /* CONFIG_SYSVIPC_SYSCTL */

  void sem_init(void);
  void msg_init(void);

  void shm_init(void);

  struct ipc_namespace;

  struct pid_namespace;

  #ifdef CONFIG_POSIX_MQUEUE

  extern void mq_clear_sbinfo(struct ipc_namespace *ns);
  extern void mq_put_mnt(struct ipc_namespace *ns);

  #else

  static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
  static inline void mq_put_mnt(struct ipc_namespace *ns) { }

  #endif
  
  #ifdef CONFIG_SYSVIPC

  void sem_init_ns(struct ipc_namespace *ns);
  void msg_init_ns(struct ipc_namespace *ns);
  void shm_init_ns(struct ipc_namespace *ns);

  
  void sem_exit_ns(struct ipc_namespace *ns);
  void msg_exit_ns(struct ipc_namespace *ns);
  void shm_exit_ns(struct ipc_namespace *ns);

  #else

  static inline void sem_init_ns(struct ipc_namespace *ns) { }
  static inline void msg_init_ns(struct ipc_namespace *ns) { }
  static inline void shm_init_ns(struct ipc_namespace *ns) { }

  
  static inline void sem_exit_ns(struct ipc_namespace *ns) { }
  static inline void msg_exit_ns(struct ipc_namespace *ns) { }
  static inline void shm_exit_ns(struct ipc_namespace *ns) { }
  #endif

  /*
   * Structure that holds the parameters needed by the ipc operations
   * (see after)
   */
  struct ipc_params {
  	key_t key;
  	int flg;
  	union {
  		size_t size;	/* for shared memories */
  		int nsems;	/* for semaphores */
  	} u;			/* holds the getnew() specific param */
  };
  
  /*
   * Structure that holds some ipc operations. This structure is used to unify
   * the calls to sys_msgget(), sys_semget(), sys_shmget()
   *      . routine to call to create a new ipc object. Can be one of newque,
   *        newary, newseg

   *      . routine to call to check permissions for a new ipc object.

   *        Can be one of security_msg_associate, security_sem_associate,
   *        security_shm_associate
   *      . routine to call for an extra check if needed
   */
  struct ipc_ops {

  	int (*getnew)(struct ipc_namespace *, struct ipc_params *);
  	int (*associate)(struct kern_ipc_perm *, int);
  	int (*more_checks)(struct kern_ipc_perm *, struct ipc_params *);

  };

  struct seq_file;

  struct ipc_ids;

  void ipc_init_ids(struct ipc_ids *ids);

  #ifdef CONFIG_PROC_FS
  void __init ipc_init_proc_interface(const char *path, const char *header,

  		int ids, int (*show)(struct seq_file *, void *));

  struct pid_namespace *ipc_seq_pid_ns(struct seq_file *);

  #else
  #define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
  #endif

  #define IPC_SEM_IDS	0
  #define IPC_MSG_IDS	1
  #define IPC_SHM_IDS	2

  #define ipcid_to_idx(id)  ((id) & IPCMNI_IDX_MASK)

  #define ipcid_to_seqx(id) ((id) >> ipcmni_seq_shift())
  #define ipcid_seq_max()	  (INT_MAX >> ipcmni_seq_shift())

  /* must be called with ids->rwsem acquired for writing */

  int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);

  /* must be called with both locks acquired. */

  void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);

  /* must be called with both locks acquired. */
  void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *);

  /* must be called with ipcp locked */

  int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);

  /**

   * ipc_get_maxidx - get the highest assigned index

   * @ids: ipc identifier set
   *
   * Called with ipc_ids.rwsem held for reading.
   */

  static inline int ipc_get_maxidx(struct ipc_ids *ids)

  {
  	if (ids->in_use == 0)
  		return -1;

  	if (ids->in_use == ipc_mni)
  		return ipc_mni - 1;

  	return ids->max_idx;

  }

  /*
   * For allocation that need to be freed by RCU.
   * Objects are reference counted, they start with reference count 1.
   * getref increases the refcount, the putref call that reduces the recount
   * to 0 schedules the rcu destruction. Caller must guarantee locking.

   *
   * refcount is initialized by ipc_addid(), before that point call_rcu()
   * must be used.

   */

  bool ipc_rcu_getref(struct kern_ipc_perm *ptr);

  void ipc_rcu_putref(struct kern_ipc_perm *ptr,
  			void (*func)(struct rcu_head *head));

  struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);

  
  void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
  void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);

  int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);

  struct kern_ipc_perm *ipcctl_obtain_check(struct ipc_namespace *ns,

  					     struct ipc_ids *ids, int id, int cmd,
  					     struct ipc64_perm *perm, int extra_perm);

  static inline void ipc_update_pid(struct pid **pos, struct pid *pid)
  {
  	struct pid *old = *pos;
  	if (old != pid) {
  		*pos = get_pid(pid);
  		put_pid(old);
  	}
  }

  #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION

  int ipc_parse_version(int *cmd);

  #endif
  
  extern void free_msg(struct msg_msg *msg);

  extern struct msg_msg *load_msg(const void __user *src, size_t len);

  extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);

  extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);

  static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int id)

  {

  	return ipcid_to_seqx(id) != ipcp->seq;

  }

  static inline void ipc_lock_object(struct kern_ipc_perm *perm)

  {

  	spin_lock(&perm->lock);
  }

  static inline void ipc_unlock_object(struct kern_ipc_perm *perm)

  {
  	spin_unlock(&perm->lock);

  }

  static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm)

  {

  	assert_spin_locked(&perm->lock);
  }

  static inline void ipc_unlock(struct kern_ipc_perm *perm)
  {

  	ipc_unlock_object(perm);

  	rcu_read_unlock();
  }

  /*
   * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths
   * where the respective ipc_ids.rwsem is not being held down.
   * Checks whether the ipc object is still around or if it's gone already, as
   * ipc_rmid() may have already freed the ID while the ipc lock was spinning.
   * Needs to be called with kern_ipc_perm.lock held -- exception made for one
   * checkpoint case at sys_semtimedop() as noted in code commentary.
   */
  static inline bool ipc_valid_object(struct kern_ipc_perm *perm)
  {

  	return !perm->deleted;

  }

  struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);

  int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,

  			const struct ipc_ops *ops, struct ipc_params *params);

  void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
  		void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));

  static inline int sem_check_semmni(struct ipc_namespace *ns) {
  	/*

  	 * Check semmni range [0, ipc_mni]

  	 * semmni is the last element of sem_ctls[4] array
  	 */

  	return ((ns->sem_ctls[3] < 0) || (ns->sem_ctls[3] > ipc_mni))

  		? -ERANGE : 0;
  }

  #ifdef CONFIG_COMPAT
  #include <linux/compat.h>
  struct compat_ipc_perm {
  	key_t key;
  	__compat_uid_t uid;
  	__compat_gid_t gid;
  	__compat_uid_t cuid;
  	__compat_gid_t cgid;
  	compat_mode_t mode;
  	unsigned short seq;
  };

  void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *);
  void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *);
  int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *);
  int get_compat_ipc64_perm(struct ipc64_perm *,
  			  struct compat_ipc64_perm __user *);

  static inline int compat_ipc_parse_version(int *cmd)
  {

  	int version = *cmd & IPC_64;
  	*cmd &= ~IPC_64;
  	return version;

  }

  long compat_ksys_old_semctl(int semid, int semnum, int cmd, int arg);
  long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr);

  long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
  			compat_long_t msgtyp, int msgflg);

  long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
  		       compat_ssize_t msgsz, int msgflg);

  long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr);

  
  #endif

  #endif