/* * 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> #define SEQ_MULTIPLIER	(IPCMNI) void sem_init(void);void msg_init(void);void shm_init(void); struct ipc_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);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);#elsestatic 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 struct ipc_rcu {	struct rcu_head rcu;	atomic_t refcount;} ____cacheline_aligned_in_smp; #define ipc_rcu_to_struct(p)  ((void *)(p+1)) /* * 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 *);#ifdef CONFIG_PROC_FSvoid __init ipc_init_proc_interface(const char *path, const char *header,		int ids, int (*show)(struct seq_file *, void *));#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) % SEQ_MULTIPLIER)#define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER)#define IPCID_SEQ_MAX min_t(int, INT_MAX/SEQ_MULTIPLIER, USHRT_MAX) /* must be called with ids->rwsem acquired for writing */int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int); /* must be called with ids->rwsem acquired for reading */int ipc_get_maxid(struct ipc_ids *); /* must be called with both locks acquired. */void ipc_rmid(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); /* for rare, potentially huge allocations. * both function can sleep */void *ipc_alloc(int size);void ipc_free(void *ptr, int size); /* * 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. */void *ipc_rcu_alloc(int size);int ipc_rcu_getref(void *ptr);void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head));void ipc_rcu_free(struct rcu_head *head); struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);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_pre_down_nolock(struct ipc_namespace *ns,					     struct ipc_ids *ids, int id, int cmd,					     struct ipc64_perm *perm, int extra_perm); #ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION/* On IA-64, we always use the "64-bit version" of the IPC structures.  */# define ipc_parse_version(cmd)	IPC_64#elseint 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); extern void recompute_msgmni(struct ipc_namespace *); static inline int ipc_buildid(int id, int seq){	return SEQ_MULTIPLIER * seq + id;} static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid){	return uid / SEQ_MULTIPLIER != 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 *));#endif