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/* SPDX-License-Identifier: GPL-2.0 */
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/*
 * linux/ipc/util.h
 * Copyright (C) 1999 Christoph Rohland
 *
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 * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>
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 * namespaces support.      2006 OpenVZ, SWsoft Inc.
 *                               Pavel Emelianov <xemul@openvz.org>
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 */

#ifndef _IPC_UTIL_H
#define _IPC_UTIL_H

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#include <linux/unistd.h>
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#include <linux/err.h>
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#define SEQ_MULTIPLIER	(IPCMNI)

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int sem_init(void);
int msg_init(void);
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void shm_init(void);
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struct ipc_namespace;

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#ifdef CONFIG_POSIX_MQUEUE
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extern void mq_clear_sbinfo(struct ipc_namespace *ns);
extern void mq_put_mnt(struct ipc_namespace *ns);
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#else
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static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
static inline void mq_put_mnt(struct ipc_namespace *ns) { }
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#endif

#ifdef CONFIG_SYSVIPC
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int sem_init_ns(struct ipc_namespace *ns);
int msg_init_ns(struct ipc_namespace *ns);
int shm_init_ns(struct ipc_namespace *ns);
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void sem_exit_ns(struct ipc_namespace *ns);
void msg_exit_ns(struct ipc_namespace *ns);
void shm_exit_ns(struct ipc_namespace *ns);
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#else
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static inline int sem_init_ns(struct ipc_namespace *ns) { return 0; }
static inline int msg_init_ns(struct ipc_namespace *ns) { return 0; }
static inline int shm_init_ns(struct ipc_namespace *ns) { return 0; }
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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
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/*
 * 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
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 *      . routine to call to check permissions for a new ipc object.
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 *        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 {
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	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 *);
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};

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struct seq_file;
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struct ipc_ids;
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int ipc_init_ids(struct ipc_ids *);
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#ifdef CONFIG_PROC_FS
void __init ipc_init_proc_interface(const char *path, const char *header,
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		int ids, int (*show)(struct seq_file *, void *));
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#else
#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
#endif
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#define IPC_SEM_IDS	0
#define IPC_MSG_IDS	1
#define IPC_SHM_IDS	2

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#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
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#define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER)
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#define IPCID_SEQ_MAX min_t(int, INT_MAX/SEQ_MULTIPLIER, USHRT_MAX)
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/* must be called with ids->rwsem acquired for writing */
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int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
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/* must be called with ids->rwsem acquired for reading */
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int ipc_get_maxid(struct ipc_ids *);
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/* must be called with both locks acquired. */
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void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
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/* must be called with both locks acquired. */
void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *);

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/* must be called with ipcp locked */
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int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
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/*
 * 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.
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 *
 * refcount is initialized by ipc_addid(), before that point call_rcu()
 * must be used.
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 */
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int ipc_rcu_getref(struct kern_ipc_perm *ptr);
void ipc_rcu_putref(struct kern_ipc_perm *ptr,
			void (*func)(struct rcu_head *head));
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struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
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struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);
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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);
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int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
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struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns,
					     struct ipc_ids *ids, int id, int cmd,
					     struct ipc64_perm *perm, int extra_perm);
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#ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
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/* On IA-64, we always use the "64-bit version" of the IPC structures.  */
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# define ipc_parse_version(cmd)	IPC_64
#else
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int ipc_parse_version(int *cmd);
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#endif

extern void free_msg(struct msg_msg *msg);
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extern struct msg_msg *load_msg(const void __user *src, size_t len);
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extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
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extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);
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static inline int ipc_buildid(int id, int seq)
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{
	return SEQ_MULTIPLIER * seq + id;
}

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static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
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{
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	return uid / SEQ_MULTIPLIER != ipcp->seq;
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}

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static inline void ipc_lock_object(struct kern_ipc_perm *perm)
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{
	spin_lock(&perm->lock);
}

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static inline void ipc_unlock_object(struct kern_ipc_perm *perm)
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{
	spin_unlock(&perm->lock);
}

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static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm)
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{
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	assert_spin_locked(&perm->lock);
}

static inline void ipc_unlock(struct kern_ipc_perm *perm)
{
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	ipc_unlock_object(perm);
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	rcu_read_unlock();
}

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/*
 * 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)
{
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	return !perm->deleted;
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}

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struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
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int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
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			const struct ipc_ops *ops, struct ipc_params *params);
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void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
		void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
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#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;
};

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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 *);

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static inline int compat_ipc_parse_version(int *cmd)
{
#ifdef	CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
	int version = *cmd & IPC_64;
	*cmd &= ~IPC_64;
	return version;
#else
	return IPC_64;
#endif
}
#endif
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#endif