3 * Copyright (C) 1999 Christoph Rohland
5 * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>
6 * namespaces support. 2006 OpenVZ, SWsoft Inc.
7 * Pavel Emelianov <xemul@openvz.org>
13 #include <linux/unistd.h>
14 #include <linux/err.h>
16 #define SEQ_MULTIPLIER (IPCMNI)
24 #ifdef CONFIG_POSIX_MQUEUE
25 extern void mq_clear_sbinfo(struct ipc_namespace
*ns
);
26 extern void mq_put_mnt(struct ipc_namespace
*ns
);
28 static inline void mq_clear_sbinfo(struct ipc_namespace
*ns
) { }
29 static inline void mq_put_mnt(struct ipc_namespace
*ns
) { }
33 void sem_init_ns(struct ipc_namespace
*ns
);
34 void msg_init_ns(struct ipc_namespace
*ns
);
35 void shm_init_ns(struct ipc_namespace
*ns
);
37 void sem_exit_ns(struct ipc_namespace
*ns
);
38 void msg_exit_ns(struct ipc_namespace
*ns
);
39 void shm_exit_ns(struct ipc_namespace
*ns
);
41 static inline void sem_init_ns(struct ipc_namespace
*ns
) { }
42 static inline void msg_init_ns(struct ipc_namespace
*ns
) { }
43 static inline void shm_init_ns(struct ipc_namespace
*ns
) { }
45 static inline void sem_exit_ns(struct ipc_namespace
*ns
) { }
46 static inline void msg_exit_ns(struct ipc_namespace
*ns
) { }
47 static inline void shm_exit_ns(struct ipc_namespace
*ns
) { }
53 } ____cacheline_aligned_in_smp
;
55 #define ipc_rcu_to_struct(p) ((void *)(p+1))
58 * Structure that holds the parameters needed by the ipc operations
65 size_t size
; /* for shared memories */
66 int nsems
; /* for semaphores */
67 } u
; /* holds the getnew() specific param */
71 * Structure that holds some ipc operations. This structure is used to unify
72 * the calls to sys_msgget(), sys_semget(), sys_shmget()
73 * . routine to call to create a new ipc object. Can be one of newque,
75 * . routine to call to check permissions for a new ipc object.
76 * Can be one of security_msg_associate, security_sem_associate,
77 * security_shm_associate
78 * . routine to call for an extra check if needed
81 int (*getnew
)(struct ipc_namespace
*, struct ipc_params
*);
82 int (*associate
)(struct kern_ipc_perm
*, int);
83 int (*more_checks
)(struct kern_ipc_perm
*, struct ipc_params
*);
89 void ipc_init_ids(struct ipc_ids
*);
91 void __init
ipc_init_proc_interface(const char *path
, const char *header
,
92 int ids
, int (*show
)(struct seq_file
*, void *));
94 #define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
101 #define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
102 #define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER)
103 #define IPCID_SEQ_MAX min_t(int, INT_MAX/SEQ_MULTIPLIER, USHRT_MAX)
105 /* must be called with ids->rwsem acquired for writing */
106 int ipc_addid(struct ipc_ids
*, struct kern_ipc_perm
*, int);
108 /* must be called with ids->rwsem acquired for reading */
109 int ipc_get_maxid(struct ipc_ids
*);
111 /* must be called with both locks acquired. */
112 void ipc_rmid(struct ipc_ids
*, struct kern_ipc_perm
*);
114 /* must be called with ipcp locked */
115 int ipcperms(struct ipc_namespace
*ns
, struct kern_ipc_perm
*ipcp
, short flg
);
117 /* for rare, potentially huge allocations.
118 * both function can sleep
120 void *ipc_alloc(int size
);
121 void ipc_free(void *ptr
);
124 * For allocation that need to be freed by RCU.
125 * Objects are reference counted, they start with reference count 1.
126 * getref increases the refcount, the putref call that reduces the recount
127 * to 0 schedules the rcu destruction. Caller must guarantee locking.
129 void *ipc_rcu_alloc(int size
);
130 int ipc_rcu_getref(void *ptr
);
131 void ipc_rcu_putref(void *ptr
, void (*func
)(struct rcu_head
*head
));
132 void ipc_rcu_free(struct rcu_head
*head
);
134 struct kern_ipc_perm
*ipc_lock(struct ipc_ids
*, int);
135 struct kern_ipc_perm
*ipc_obtain_object_idr(struct ipc_ids
*ids
, int id
);
137 void kernel_to_ipc64_perm(struct kern_ipc_perm
*in
, struct ipc64_perm
*out
);
138 void ipc64_perm_to_ipc_perm(struct ipc64_perm
*in
, struct ipc_perm
*out
);
139 int ipc_update_perm(struct ipc64_perm
*in
, struct kern_ipc_perm
*out
);
140 struct kern_ipc_perm
*ipcctl_pre_down_nolock(struct ipc_namespace
*ns
,
141 struct ipc_ids
*ids
, int id
, int cmd
,
142 struct ipc64_perm
*perm
, int extra_perm
);
144 #ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
145 /* On IA-64, we always use the "64-bit version" of the IPC structures. */
146 # define ipc_parse_version(cmd) IPC_64
148 int ipc_parse_version(int *cmd
);
151 extern void free_msg(struct msg_msg
*msg
);
152 extern struct msg_msg
*load_msg(const void __user
*src
, size_t len
);
153 extern struct msg_msg
*copy_msg(struct msg_msg
*src
, struct msg_msg
*dst
);
154 extern int store_msg(void __user
*dest
, struct msg_msg
*msg
, size_t len
);
156 extern void recompute_msgmni(struct ipc_namespace
*);
158 static inline int ipc_buildid(int id
, int seq
)
160 return SEQ_MULTIPLIER
* seq
+ id
;
163 static inline int ipc_checkid(struct kern_ipc_perm
*ipcp
, int uid
)
165 return uid
/ SEQ_MULTIPLIER
!= ipcp
->seq
;
168 static inline void ipc_lock_object(struct kern_ipc_perm
*perm
)
170 spin_lock(&perm
->lock
);
173 static inline void ipc_unlock_object(struct kern_ipc_perm
*perm
)
175 spin_unlock(&perm
->lock
);
178 static inline void ipc_assert_locked_object(struct kern_ipc_perm
*perm
)
180 assert_spin_locked(&perm
->lock
);
183 static inline void ipc_unlock(struct kern_ipc_perm
*perm
)
185 ipc_unlock_object(perm
);
190 * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths
191 * where the respective ipc_ids.rwsem is not being held down.
192 * Checks whether the ipc object is still around or if it's gone already, as
193 * ipc_rmid() may have already freed the ID while the ipc lock was spinning.
194 * Needs to be called with kern_ipc_perm.lock held -- exception made for one
195 * checkpoint case at sys_semtimedop() as noted in code commentary.
197 static inline bool ipc_valid_object(struct kern_ipc_perm
*perm
)
199 return !perm
->deleted
;
202 struct kern_ipc_perm
*ipc_obtain_object_check(struct ipc_ids
*ids
, int id
);
203 int ipcget(struct ipc_namespace
*ns
, struct ipc_ids
*ids
,
204 const struct ipc_ops
*ops
, struct ipc_params
*params
);
205 void free_ipcs(struct ipc_namespace
*ns
, struct ipc_ids
*ids
,
206 void (*free
)(struct ipc_namespace
*, struct kern_ipc_perm
*));