/* 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_SYSCTLextern 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_MQUEUEextern void mq_clear_sbinfo(struct ipc_namespace *ns);extern void mq_put_mnt(struct ipc_namespace *ns);#elsestatic inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }static inline void mq_put_mnt(struct ipc_namespace *ns) { }#endif #ifdef CONFIG_SYSVIPCvoid sem_init_ns(struct ipc_namespace *ns);int 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);#elsestatic inline void sem_init_ns(struct ipc_namespace *ns) { }static inline int msg_init_ns(struct ipc_namespace *ns) { return 0; }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_FSvoid __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 * * The function returns the highest assigned index for @ids. The function * doesn't scan the idr tree, it uses a cached value. * * 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_VERSIONint 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