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git.ipfire.org Git - thirdparty/linux.git/blob - ipc/util.h
1 /* SPDX-License-Identifier: GPL-2.0 */
4 * Copyright (C) 1999 Christoph Rohland
6 * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>
7 * namespaces support. 2006 OpenVZ, SWsoft Inc.
8 * Pavel Emelianov <xemul@openvz.org>
14 #include <linux/unistd.h>
15 #include <linux/err.h>
16 #include <linux/ipc_namespace.h>
19 * The IPC ID contains 2 separate numbers - index and sequence number.
21 * bits 0-14: index (32k, 15 bits)
22 * bits 15-30: sequence number (64k, 16 bits)
24 * When IPCMNI extension mode is turned on, the composition changes:
25 * bits 0-23: index (16M, 24 bits)
26 * bits 24-30: sequence number (128, 7 bits)
28 #define IPCMNI_SHIFT 15
29 #define IPCMNI_EXTEND_SHIFT 24
30 #define IPCMNI_EXTEND_MIN_CYCLE (RADIX_TREE_MAP_SIZE * RADIX_TREE_MAP_SIZE)
31 #define IPCMNI (1 << IPCMNI_SHIFT)
32 #define IPCMNI_EXTEND (1 << IPCMNI_EXTEND_SHIFT)
34 #ifdef CONFIG_SYSVIPC_SYSCTL
36 extern int ipc_mni_shift
;
37 extern int ipc_min_cycle
;
39 #define ipcmni_seq_shift() ipc_mni_shift
40 #define IPCMNI_IDX_MASK ((1 << ipc_mni_shift) - 1)
42 #else /* CONFIG_SYSVIPC_SYSCTL */
44 #define ipc_mni IPCMNI
45 #define ipc_min_cycle ((int)RADIX_TREE_MAP_SIZE)
46 #define ipcmni_seq_shift() IPCMNI_SHIFT
47 #define IPCMNI_IDX_MASK ((1 << IPCMNI_SHIFT) - 1)
48 #endif /* CONFIG_SYSVIPC_SYSCTL */
57 #ifdef CONFIG_POSIX_MQUEUE
58 extern void mq_clear_sbinfo(struct ipc_namespace
*ns
);
60 static inline void mq_clear_sbinfo(struct ipc_namespace
*ns
) { }
64 void sem_init_ns(struct ipc_namespace
*ns
);
65 int msg_init_ns(struct ipc_namespace
*ns
);
66 void shm_init_ns(struct ipc_namespace
*ns
);
68 void sem_exit_ns(struct ipc_namespace
*ns
);
69 void msg_exit_ns(struct ipc_namespace
*ns
);
70 void shm_exit_ns(struct ipc_namespace
*ns
);
72 static inline void sem_init_ns(struct ipc_namespace
*ns
) { }
73 static inline int msg_init_ns(struct ipc_namespace
*ns
) { return 0; }
74 static inline void shm_init_ns(struct ipc_namespace
*ns
) { }
76 static inline void sem_exit_ns(struct ipc_namespace
*ns
) { }
77 static inline void msg_exit_ns(struct ipc_namespace
*ns
) { }
78 static inline void shm_exit_ns(struct ipc_namespace
*ns
) { }
82 * Structure that holds the parameters needed by the ipc operations
89 size_t size
; /* for shared memories */
90 int nsems
; /* for semaphores */
91 } u
; /* holds the getnew() specific param */
95 * Structure that holds some ipc operations. This structure is used to unify
96 * the calls to sys_msgget(), sys_semget(), sys_shmget()
97 * . routine to call to create a new ipc object. Can be one of newque,
99 * . routine to call to check permissions for a new ipc object.
100 * Can be one of security_msg_associate, security_sem_associate,
101 * security_shm_associate
102 * . routine to call for an extra check if needed
105 int (*getnew
)(struct ipc_namespace
*, struct ipc_params
*);
106 int (*associate
)(struct kern_ipc_perm
*, int);
107 int (*more_checks
)(struct kern_ipc_perm
*, struct ipc_params
*);
113 void ipc_init_ids(struct ipc_ids
*ids
);
114 #ifdef CONFIG_PROC_FS
115 void __init
ipc_init_proc_interface(const char *path
, const char *header
,
116 int ids
, int (*show
)(struct seq_file
*, void *));
117 struct pid_namespace
*ipc_seq_pid_ns(struct seq_file
*);
119 #define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
122 #define IPC_SEM_IDS 0
123 #define IPC_MSG_IDS 1
124 #define IPC_SHM_IDS 2
126 #define ipcid_to_idx(id) ((id) & IPCMNI_IDX_MASK)
127 #define ipcid_to_seqx(id) ((id) >> ipcmni_seq_shift())
128 #define ipcid_seq_max() (INT_MAX >> ipcmni_seq_shift())
130 /* must be called with ids->rwsem acquired for writing */
131 int ipc_addid(struct ipc_ids
*, struct kern_ipc_perm
*, int);
133 /* must be called with both locks acquired. */
134 void ipc_rmid(struct ipc_ids
*, struct kern_ipc_perm
*);
136 /* must be called with both locks acquired. */
137 void ipc_set_key_private(struct ipc_ids
*, struct kern_ipc_perm
*);
139 /* must be called with ipcp locked */
140 int ipcperms(struct ipc_namespace
*ns
, struct kern_ipc_perm
*ipcp
, short flg
);
143 * ipc_get_maxidx - get the highest assigned index
144 * @ids: ipc identifier set
146 * The function returns the highest assigned index for @ids. The function
147 * doesn't scan the idr tree, it uses a cached value.
149 * Called with ipc_ids.rwsem held for reading.
151 static inline int ipc_get_maxidx(struct ipc_ids
*ids
)
153 if (ids
->in_use
== 0)
156 if (ids
->in_use
== ipc_mni
)
163 * For allocation that need to be freed by RCU.
164 * Objects are reference counted, they start with reference count 1.
165 * getref increases the refcount, the putref call that reduces the recount
166 * to 0 schedules the rcu destruction. Caller must guarantee locking.
168 * refcount is initialized by ipc_addid(), before that point call_rcu()
171 bool ipc_rcu_getref(struct kern_ipc_perm
*ptr
);
172 void ipc_rcu_putref(struct kern_ipc_perm
*ptr
,
173 void (*func
)(struct rcu_head
*head
));
175 struct kern_ipc_perm
*ipc_obtain_object_idr(struct ipc_ids
*ids
, int id
);
177 void kernel_to_ipc64_perm(struct kern_ipc_perm
*in
, struct ipc64_perm
*out
);
178 void ipc64_perm_to_ipc_perm(struct ipc64_perm
*in
, struct ipc_perm
*out
);
179 int ipc_update_perm(struct ipc64_perm
*in
, struct kern_ipc_perm
*out
);
180 struct kern_ipc_perm
*ipcctl_obtain_check(struct ipc_namespace
*ns
,
181 struct ipc_ids
*ids
, int id
, int cmd
,
182 struct ipc64_perm
*perm
, int extra_perm
);
184 static inline void ipc_update_pid(struct pid
**pos
, struct pid
*pid
)
186 struct pid
*old
= *pos
;
193 #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
194 int ipc_parse_version(int *cmd
);
197 extern void free_msg(struct msg_msg
*msg
);
198 extern struct msg_msg
*load_msg(const void __user
*src
, size_t len
);
199 extern struct msg_msg
*copy_msg(struct msg_msg
*src
, struct msg_msg
*dst
);
200 extern int store_msg(void __user
*dest
, struct msg_msg
*msg
, size_t len
);
202 static inline int ipc_checkid(struct kern_ipc_perm
*ipcp
, int id
)
204 return ipcid_to_seqx(id
) != ipcp
->seq
;
207 static inline void ipc_lock_object(struct kern_ipc_perm
*perm
)
209 spin_lock(&perm
->lock
);
212 static inline void ipc_unlock_object(struct kern_ipc_perm
*perm
)
214 spin_unlock(&perm
->lock
);
217 static inline void ipc_assert_locked_object(struct kern_ipc_perm
*perm
)
219 assert_spin_locked(&perm
->lock
);
222 static inline void ipc_unlock(struct kern_ipc_perm
*perm
)
224 ipc_unlock_object(perm
);
229 * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths
230 * where the respective ipc_ids.rwsem is not being held down.
231 * Checks whether the ipc object is still around or if it's gone already, as
232 * ipc_rmid() may have already freed the ID while the ipc lock was spinning.
233 * Needs to be called with kern_ipc_perm.lock held -- exception made for one
234 * checkpoint case at sys_semtimedop() as noted in code commentary.
236 static inline bool ipc_valid_object(struct kern_ipc_perm
*perm
)
238 return !perm
->deleted
;
241 struct kern_ipc_perm
*ipc_obtain_object_check(struct ipc_ids
*ids
, int id
);
242 int ipcget(struct ipc_namespace
*ns
, struct ipc_ids
*ids
,
243 const struct ipc_ops
*ops
, struct ipc_params
*params
);
244 void free_ipcs(struct ipc_namespace
*ns
, struct ipc_ids
*ids
,
245 void (*free
)(struct ipc_namespace
*, struct kern_ipc_perm
*));
247 static inline int sem_check_semmni(struct ipc_namespace
*ns
) {
249 * Check semmni range [0, ipc_mni]
250 * semmni is the last element of sem_ctls[4] array
252 return ((ns
->sem_ctls
[3] < 0) || (ns
->sem_ctls
[3] > ipc_mni
))
257 #include <linux/compat.h>
258 struct compat_ipc_perm
{
268 void to_compat_ipc_perm(struct compat_ipc_perm
*, struct ipc64_perm
*);
269 void to_compat_ipc64_perm(struct compat_ipc64_perm
*, struct ipc64_perm
*);
270 int get_compat_ipc_perm(struct ipc64_perm
*, struct compat_ipc_perm __user
*);
271 int get_compat_ipc64_perm(struct ipc64_perm
*,
272 struct compat_ipc64_perm __user
*);
274 static inline int compat_ipc_parse_version(int *cmd
)
276 int version
= *cmd
& IPC_64
;
281 long compat_ksys_old_semctl(int semid
, int semnum
, int cmd
, int arg
);
282 long compat_ksys_old_msgctl(int msqid
, int cmd
, void __user
*uptr
);
283 long compat_ksys_msgrcv(int msqid
, compat_uptr_t msgp
, compat_ssize_t msgsz
,
284 compat_long_t msgtyp
, int msgflg
);
285 long compat_ksys_msgsnd(int msqid
, compat_uptr_t msgp
,
286 compat_ssize_t msgsz
, int msgflg
);
287 long compat_ksys_old_shmctl(int shmid
, int cmd
, void __user
*uptr
);