ipc: conserve sequence numbers in ipcmni_extend mode
[linux-2.6-block.git] / ipc / util.h
CommitLineData
b2441318 1/* SPDX-License-Identifier: GPL-2.0 */
1da177e4
LT
2/*
3 * linux/ipc/util.h
4 * Copyright (C) 1999 Christoph Rohland
5 *
624dffcb 6 * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>
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7 * namespaces support. 2006 OpenVZ, SWsoft Inc.
8 * Pavel Emelianov <xemul@openvz.org>
1da177e4
LT
9 */
10
11#ifndef _IPC_UTIL_H
12#define _IPC_UTIL_H
13
232086b1 14#include <linux/unistd.h>
023a5355 15#include <linux/err.h>
15df03c8 16#include <linux/ipc_namespace.h>
7ca7e564 17
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18/*
19 * The IPC ID contains 2 separate numbers - index and sequence number.
20 * By default,
21 * bits 0-14: index (32k, 15 bits)
22 * bits 15-30: sequence number (64k, 16 bits)
23 *
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)
27 */
28#define IPCMNI_SHIFT 15
29#define IPCMNI_EXTEND_SHIFT 24
30#define IPCMNI (1 << IPCMNI_SHIFT)
31#define IPCMNI_EXTEND (1 << IPCMNI_EXTEND_SHIFT)
32
33#ifdef CONFIG_SYSVIPC_SYSCTL
34extern int ipc_mni;
35extern int ipc_mni_shift;
36
3278a2c2 37#define ipcmni_seq_shift() ipc_mni_shift
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38#define IPCMNI_IDX_MASK ((1 << ipc_mni_shift) - 1)
39
40#else /* CONFIG_SYSVIPC_SYSCTL */
41
42#define ipc_mni IPCMNI
3278a2c2 43#define ipcmni_seq_shift() IPCMNI_SHIFT
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44#define IPCMNI_IDX_MASK ((1 << IPCMNI_SHIFT) - 1)
45#endif /* CONFIG_SYSVIPC_SYSCTL */
1da177e4 46
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47void sem_init(void);
48void msg_init(void);
239521f3 49void shm_init(void);
1da177e4 50
ae5e1b22 51struct ipc_namespace;
03f1fc09 52struct pid_namespace;
ae5e1b22 53
614b84cf 54#ifdef CONFIG_POSIX_MQUEUE
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55extern void mq_clear_sbinfo(struct ipc_namespace *ns);
56extern void mq_put_mnt(struct ipc_namespace *ns);
614b84cf 57#else
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58static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
59static inline void mq_put_mnt(struct ipc_namespace *ns) { }
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60#endif
61
62#ifdef CONFIG_SYSVIPC
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63void sem_init_ns(struct ipc_namespace *ns);
64void msg_init_ns(struct ipc_namespace *ns);
65void shm_init_ns(struct ipc_namespace *ns);
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66
67void sem_exit_ns(struct ipc_namespace *ns);
68void msg_exit_ns(struct ipc_namespace *ns);
69void shm_exit_ns(struct ipc_namespace *ns);
614b84cf 70#else
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DB
71static inline void sem_init_ns(struct ipc_namespace *ns) { }
72static inline void msg_init_ns(struct ipc_namespace *ns) { }
73static inline void shm_init_ns(struct ipc_namespace *ns) { }
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74
75static inline void sem_exit_ns(struct ipc_namespace *ns) { }
76static inline void msg_exit_ns(struct ipc_namespace *ns) { }
77static inline void shm_exit_ns(struct ipc_namespace *ns) { }
78#endif
73ea4130 79
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80/*
81 * Structure that holds the parameters needed by the ipc operations
82 * (see after)
83 */
84struct ipc_params {
85 key_t key;
86 int flg;
87 union {
88 size_t size; /* for shared memories */
89 int nsems; /* for semaphores */
90 } u; /* holds the getnew() specific param */
91};
92
93/*
94 * Structure that holds some ipc operations. This structure is used to unify
95 * the calls to sys_msgget(), sys_semget(), sys_shmget()
96 * . routine to call to create a new ipc object. Can be one of newque,
97 * newary, newseg
f4566f04 98 * . routine to call to check permissions for a new ipc object.
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99 * Can be one of security_msg_associate, security_sem_associate,
100 * security_shm_associate
101 * . routine to call for an extra check if needed
102 */
103struct ipc_ops {
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104 int (*getnew)(struct ipc_namespace *, struct ipc_params *);
105 int (*associate)(struct kern_ipc_perm *, int);
106 int (*more_checks)(struct kern_ipc_perm *, struct ipc_params *);
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107};
108
ae781774 109struct seq_file;
ed2ddbf8 110struct ipc_ids;
7d69a1f4 111
eae04d25 112void ipc_init_ids(struct ipc_ids *ids);
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113#ifdef CONFIG_PROC_FS
114void __init ipc_init_proc_interface(const char *path, const char *header,
73ea4130 115 int ids, int (*show)(struct seq_file *, void *));
03f1fc09 116struct pid_namespace *ipc_seq_pid_ns(struct seq_file *);
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117#else
118#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
119#endif
1da177e4 120
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121#define IPC_SEM_IDS 0
122#define IPC_MSG_IDS 1
123#define IPC_SHM_IDS 2
124
5ac893b8 125#define ipcid_to_idx(id) ((id) & IPCMNI_IDX_MASK)
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126#define ipcid_to_seqx(id) ((id) >> ipcmni_seq_shift())
127#define ipcid_seq_max() (INT_MAX >> ipcmni_seq_shift())
ce621f5b 128
d9a605e4 129/* must be called with ids->rwsem acquired for writing */
7ca7e564 130int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
3e148c79 131
1da177e4 132/* must be called with both locks acquired. */
7ca7e564 133void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
1da177e4 134
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135/* must be called with both locks acquired. */
136void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *);
137
f4566f04 138/* must be called with ipcp locked */
b0e77598 139int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
1da177e4 140
15df03c8 141/**
27c331a1 142 * ipc_get_maxidx - get the highest assigned index
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143 * @ids: ipc identifier set
144 *
145 * Called with ipc_ids.rwsem held for reading.
146 */
27c331a1 147static inline int ipc_get_maxidx(struct ipc_ids *ids)
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DB
148{
149 if (ids->in_use == 0)
150 return -1;
151
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152 if (ids->in_use == ipc_mni)
153 return ipc_mni - 1;
15df03c8 154
27c331a1 155 return ids->max_idx;
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156}
157
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158/*
159 * For allocation that need to be freed by RCU.
160 * Objects are reference counted, they start with reference count 1.
161 * getref increases the refcount, the putref call that reduces the recount
162 * to 0 schedules the rcu destruction. Caller must guarantee locking.
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MS
163 *
164 * refcount is initialized by ipc_addid(), before that point call_rcu()
165 * must be used.
1da177e4 166 */
2a9d6481 167bool ipc_rcu_getref(struct kern_ipc_perm *ptr);
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168void ipc_rcu_putref(struct kern_ipc_perm *ptr,
169 void (*func)(struct rcu_head *head));
1da177e4 170
55b7ae50 171struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);
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172
173void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
174void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
1efdb69b 175int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
4241c1a3 176struct kern_ipc_perm *ipcctl_obtain_check(struct ipc_namespace *ns,
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177 struct ipc_ids *ids, int id, int cmd,
178 struct ipc64_perm *perm, int extra_perm);
1da177e4 179
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180static inline void ipc_update_pid(struct pid **pos, struct pid *pid)
181{
182 struct pid *old = *pos;
183 if (old != pid) {
184 *pos = get_pid(pid);
185 put_pid(old);
186 }
187}
188
275f2214 189#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
239521f3 190int ipc_parse_version(int *cmd);
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191#endif
192
193extern void free_msg(struct msg_msg *msg);
4e9b45a1 194extern struct msg_msg *load_msg(const void __user *src, size_t len);
4a674f34 195extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
4e9b45a1 196extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);
7748dbfa 197
27c331a1 198static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int id)
023a5355 199{
27c331a1 200 return ipcid_to_seqx(id) != ipcp->seq;
023a5355
ND
201}
202
1ca7003a 203static inline void ipc_lock_object(struct kern_ipc_perm *perm)
023a5355 204{
023a5355
ND
205 spin_lock(&perm->lock);
206}
207
1ca7003a 208static inline void ipc_unlock_object(struct kern_ipc_perm *perm)
023a5355
ND
209{
210 spin_unlock(&perm->lock);
023a5355
ND
211}
212
1ca7003a 213static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm)
16df3674 214{
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215 assert_spin_locked(&perm->lock);
216}
217
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218static inline void ipc_unlock(struct kern_ipc_perm *perm)
219{
cf9d5d78 220 ipc_unlock_object(perm);
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221 rcu_read_unlock();
222}
223
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224/*
225 * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths
226 * where the respective ipc_ids.rwsem is not being held down.
227 * Checks whether the ipc object is still around or if it's gone already, as
228 * ipc_rmid() may have already freed the ID while the ipc lock was spinning.
229 * Needs to be called with kern_ipc_perm.lock held -- exception made for one
230 * checkpoint case at sys_semtimedop() as noted in code commentary.
231 */
232static inline bool ipc_valid_object(struct kern_ipc_perm *perm)
233{
72a8ff2f 234 return !perm->deleted;
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RA
235}
236
4d2bff5e 237struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
b2d75cdd 238int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
eb66ec44 239 const struct ipc_ops *ops, struct ipc_params *params);
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AD
240void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
241 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
553f770e 242
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243static inline int sem_check_semmni(struct ipc_namespace *ns) {
244 /*
5ac893b8 245 * Check semmni range [0, ipc_mni]
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246 * semmni is the last element of sem_ctls[4] array
247 */
5ac893b8 248 return ((ns->sem_ctls[3] < 0) || (ns->sem_ctls[3] > ipc_mni))
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WL
249 ? -ERANGE : 0;
250}
251
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AV
252#ifdef CONFIG_COMPAT
253#include <linux/compat.h>
254struct compat_ipc_perm {
255 key_t key;
256 __compat_uid_t uid;
257 __compat_gid_t gid;
258 __compat_uid_t cuid;
259 __compat_gid_t cgid;
260 compat_mode_t mode;
261 unsigned short seq;
262};
263
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AV
264void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *);
265void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *);
266int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *);
267int get_compat_ipc64_perm(struct ipc64_perm *,
268 struct compat_ipc64_perm __user *);
269
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AV
270static inline int compat_ipc_parse_version(int *cmd)
271{
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AV
272 int version = *cmd & IPC_64;
273 *cmd &= ~IPC_64;
274 return version;
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AV
275}
276#endif
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DB
277
278/* for __ARCH_WANT_SYS_IPC */
279long ksys_semtimedop(int semid, struct sembuf __user *tsops,
280 unsigned int nsops,
21fc538d 281 const struct __kernel_timespec __user *timeout);
69894718 282long ksys_semget(key_t key, int nsems, int semflg);
275f2214 283long ksys_old_semctl(int semid, int semnum, int cmd, unsigned long arg);
3d65661a 284long ksys_msgget(key_t key, int msgflg);
275f2214 285long ksys_old_msgctl(int msqid, int cmd, struct msqid_ds __user *buf);
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286long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
287 long msgtyp, int msgflg);
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288long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
289 int msgflg);
65749e0b 290long ksys_shmget(key_t key, size_t size, int shmflg);
da1e2744 291long ksys_shmdt(char __user *shmaddr);
275f2214 292long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf);
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293
294/* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */
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295long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems,
296 unsigned int nsops,
9afc5eee 297 const struct old_timespec32 __user *timeout);
b0d17578 298#ifdef CONFIG_COMPAT
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AB
299long compat_ksys_old_semctl(int semid, int semnum, int cmd, int arg);
300long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr);
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301long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
302 compat_long_t msgtyp, int msgflg);
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303long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
304 compat_ssize_t msgsz, int msgflg);
275f2214 305long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr);
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DB
306#endif /* CONFIG_COMPAT */
307
1da177e4 308#endif