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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
);
59 extern void mq_put_mnt(struct ipc_namespace
*ns
);
61 static inline void mq_clear_sbinfo(struct ipc_namespace
*ns
) { }
62 static inline void mq_put_mnt(struct ipc_namespace
*ns
) { }
66 void sem_init_ns(struct ipc_namespace
*ns
);
67 void msg_init_ns(struct ipc_namespace
*ns
);
68 void shm_init_ns(struct ipc_namespace
*ns
);
70 void sem_exit_ns(struct ipc_namespace
*ns
);
71 void msg_exit_ns(struct ipc_namespace
*ns
);
72 void shm_exit_ns(struct ipc_namespace
*ns
);
74 static inline void sem_init_ns(struct ipc_namespace
*ns
) { }
75 static inline void msg_init_ns(struct ipc_namespace
*ns
) { }
76 static inline void shm_init_ns(struct ipc_namespace
*ns
) { }
78 static inline void sem_exit_ns(struct ipc_namespace
*ns
) { }
79 static inline void msg_exit_ns(struct ipc_namespace
*ns
) { }
80 static inline void shm_exit_ns(struct ipc_namespace
*ns
) { }
84 * Structure that holds the parameters needed by the ipc operations
91 size_t size
; /* for shared memories */
92 int nsems
; /* for semaphores */
93 } u
; /* holds the getnew() specific param */
97 * Structure that holds some ipc operations. This structure is used to unify
98 * the calls to sys_msgget(), sys_semget(), sys_shmget()
99 * . routine to call to create a new ipc object. Can be one of newque,
101 * . routine to call to check permissions for a new ipc object.
102 * Can be one of security_msg_associate, security_sem_associate,
103 * security_shm_associate
104 * . routine to call for an extra check if needed
107 int (*getnew
)(struct ipc_namespace
*, struct ipc_params
*);
108 int (*associate
)(struct kern_ipc_perm
*, int);
109 int (*more_checks
)(struct kern_ipc_perm
*, struct ipc_params
*);
115 void ipc_init_ids(struct ipc_ids
*ids
);
116 #ifdef CONFIG_PROC_FS
117 void __init
ipc_init_proc_interface(const char *path
, const char *header
,
118 int ids
, int (*show
)(struct seq_file
*, void *));
119 struct pid_namespace
*ipc_seq_pid_ns(struct seq_file
*);
121 #define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
124 #define IPC_SEM_IDS 0
125 #define IPC_MSG_IDS 1
126 #define IPC_SHM_IDS 2
128 #define ipcid_to_idx(id) ((id) & IPCMNI_IDX_MASK)
129 #define ipcid_to_seqx(id) ((id) >> ipcmni_seq_shift())
130 #define ipcid_seq_max() (INT_MAX >> ipcmni_seq_shift())
132 /* must be called with ids->rwsem acquired for writing */
133 int ipc_addid(struct ipc_ids
*, struct kern_ipc_perm
*, int);
135 /* must be called with both locks acquired. */
136 void ipc_rmid(struct ipc_ids
*, struct kern_ipc_perm
*);
138 /* must be called with both locks acquired. */
139 void ipc_set_key_private(struct ipc_ids
*, struct kern_ipc_perm
*);
141 /* must be called with ipcp locked */
142 int ipcperms(struct ipc_namespace
*ns
, struct kern_ipc_perm
*ipcp
, short flg
);
145 * ipc_get_maxidx - get the highest assigned index
146 * @ids: ipc identifier set
148 * Called with ipc_ids.rwsem held for reading.
150 static inline int ipc_get_maxidx(struct ipc_ids
*ids
)
152 if (ids
->in_use
== 0)
155 if (ids
->in_use
== ipc_mni
)
162 * For allocation that need to be freed by RCU.
163 * Objects are reference counted, they start with reference count 1.
164 * getref increases the refcount, the putref call that reduces the recount
165 * to 0 schedules the rcu destruction. Caller must guarantee locking.
167 * refcount is initialized by ipc_addid(), before that point call_rcu()
170 bool ipc_rcu_getref(struct kern_ipc_perm
*ptr
);
171 void ipc_rcu_putref(struct kern_ipc_perm
*ptr
,
172 void (*func
)(struct rcu_head
*head
));
174 struct kern_ipc_perm
*ipc_obtain_object_idr(struct ipc_ids
*ids
, int id
);
176 void kernel_to_ipc64_perm(struct kern_ipc_perm
*in
, struct ipc64_perm
*out
);
177 void ipc64_perm_to_ipc_perm(struct ipc64_perm
*in
, struct ipc_perm
*out
);
178 int ipc_update_perm(struct ipc64_perm
*in
, struct kern_ipc_perm
*out
);
179 struct kern_ipc_perm
*ipcctl_obtain_check(struct ipc_namespace
*ns
,
180 struct ipc_ids
*ids
, int id
, int cmd
,
181 struct ipc64_perm
*perm
, int extra_perm
);
183 static inline void ipc_update_pid(struct pid
**pos
, struct pid
*pid
)
185 struct pid
*old
= *pos
;
192 #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
193 int ipc_parse_version(int *cmd
);
196 extern void free_msg(struct msg_msg
*msg
);
197 extern struct msg_msg
*load_msg(const void __user
*src
, size_t len
);
198 extern struct msg_msg
*copy_msg(struct msg_msg
*src
, struct msg_msg
*dst
);
199 extern int store_msg(void __user
*dest
, struct msg_msg
*msg
, size_t len
);
201 static inline int ipc_checkid(struct kern_ipc_perm
*ipcp
, int id
)
203 return ipcid_to_seqx(id
) != ipcp
->seq
;
206 static inline void ipc_lock_object(struct kern_ipc_perm
*perm
)
208 spin_lock(&perm
->lock
);
211 static inline void ipc_unlock_object(struct kern_ipc_perm
*perm
)
213 spin_unlock(&perm
->lock
);
216 static inline void ipc_assert_locked_object(struct kern_ipc_perm
*perm
)
218 assert_spin_locked(&perm
->lock
);
221 static inline void ipc_unlock(struct kern_ipc_perm
*perm
)
223 ipc_unlock_object(perm
);
228 * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths
229 * where the respective ipc_ids.rwsem is not being held down.
230 * Checks whether the ipc object is still around or if it's gone already, as
231 * ipc_rmid() may have already freed the ID while the ipc lock was spinning.
232 * Needs to be called with kern_ipc_perm.lock held -- exception made for one
233 * checkpoint case at sys_semtimedop() as noted in code commentary.
235 static inline bool ipc_valid_object(struct kern_ipc_perm
*perm
)
237 return !perm
->deleted
;
240 struct kern_ipc_perm
*ipc_obtain_object_check(struct ipc_ids
*ids
, int id
);
241 int ipcget(struct ipc_namespace
*ns
, struct ipc_ids
*ids
,
242 const struct ipc_ops
*ops
, struct ipc_params
*params
);
243 void free_ipcs(struct ipc_namespace
*ns
, struct ipc_ids
*ids
,
244 void (*free
)(struct ipc_namespace
*, struct kern_ipc_perm
*));
246 static inline int sem_check_semmni(struct ipc_namespace
*ns
) {
248 * Check semmni range [0, ipc_mni]
249 * semmni is the last element of sem_ctls[4] array
251 return ((ns
->sem_ctls
[3] < 0) || (ns
->sem_ctls
[3] > ipc_mni
))
256 #include <linux/compat.h>
257 struct compat_ipc_perm
{
267 void to_compat_ipc_perm(struct compat_ipc_perm
*, struct ipc64_perm
*);
268 void to_compat_ipc64_perm(struct compat_ipc64_perm
*, struct ipc64_perm
*);
269 int get_compat_ipc_perm(struct ipc64_perm
*, struct compat_ipc_perm __user
*);
270 int get_compat_ipc64_perm(struct ipc64_perm
*,
271 struct compat_ipc64_perm __user
*);
273 static inline int compat_ipc_parse_version(int *cmd
)
275 int version
= *cmd
& IPC_64
;
281 /* for __ARCH_WANT_SYS_IPC */
282 long ksys_semtimedop(int semid
, struct sembuf __user
*tsops
,
284 const struct __kernel_timespec __user
*timeout
);
285 long ksys_semget(key_t key
, int nsems
, int semflg
);
286 long ksys_old_semctl(int semid
, int semnum
, int cmd
, unsigned long arg
);
287 long ksys_msgget(key_t key
, int msgflg
);
288 long ksys_old_msgctl(int msqid
, int cmd
, struct msqid_ds __user
*buf
);
289 long ksys_msgrcv(int msqid
, struct msgbuf __user
*msgp
, size_t msgsz
,
290 long msgtyp
, int msgflg
);
291 long ksys_msgsnd(int msqid
, struct msgbuf __user
*msgp
, size_t msgsz
,
293 long ksys_shmget(key_t key
, size_t size
, int shmflg
);
294 long ksys_shmdt(char __user
*shmaddr
);
295 long ksys_old_shmctl(int shmid
, int cmd
, struct shmid_ds __user
*buf
);
297 /* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */
298 long compat_ksys_semtimedop(int semid
, struct sembuf __user
*tsems
,
300 const struct old_timespec32 __user
*timeout
);
302 long compat_ksys_old_semctl(int semid
, int semnum
, int cmd
, int arg
);
303 long compat_ksys_old_msgctl(int msqid
, int cmd
, void __user
*uptr
);
304 long compat_ksys_msgrcv(int msqid
, compat_uptr_t msgp
, compat_ssize_t msgsz
,
305 compat_long_t msgtyp
, int msgflg
);
306 long compat_ksys_msgsnd(int msqid
, compat_uptr_t msgp
,
307 compat_ssize_t msgsz
, int msgflg
);
308 long compat_ksys_old_shmctl(int shmid
, int cmd
, void __user
*uptr
);
309 #endif /* CONFIG_COMPAT */