Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6-block.git] / ipc / util.h
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b2441318 1/* SPDX-License-Identifier: GPL-2.0 */
1da177e4
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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>
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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
f83a396d 18#define IPCMNI 32768 /* <= MAX_INT limit for ipc arrays (including sysctl changes) */
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19#define SEQ_MULTIPLIER (IPCMNI)
20
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21int sem_init(void);
22int msg_init(void);
239521f3 23void shm_init(void);
1da177e4 24
ae5e1b22 25struct ipc_namespace;
03f1fc09 26struct pid_namespace;
ae5e1b22 27
614b84cf 28#ifdef CONFIG_POSIX_MQUEUE
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29extern void mq_clear_sbinfo(struct ipc_namespace *ns);
30extern void mq_put_mnt(struct ipc_namespace *ns);
614b84cf 31#else
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32static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
33static inline void mq_put_mnt(struct ipc_namespace *ns) { }
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34#endif
35
36#ifdef CONFIG_SYSVIPC
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37int sem_init_ns(struct ipc_namespace *ns);
38int msg_init_ns(struct ipc_namespace *ns);
39int shm_init_ns(struct ipc_namespace *ns);
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40
41void sem_exit_ns(struct ipc_namespace *ns);
42void msg_exit_ns(struct ipc_namespace *ns);
43void shm_exit_ns(struct ipc_namespace *ns);
614b84cf 44#else
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45static inline int sem_init_ns(struct ipc_namespace *ns) { return 0; }
46static inline int msg_init_ns(struct ipc_namespace *ns) { return 0; }
47static inline int shm_init_ns(struct ipc_namespace *ns) { return 0; }
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48
49static inline void sem_exit_ns(struct ipc_namespace *ns) { }
50static inline void msg_exit_ns(struct ipc_namespace *ns) { }
51static inline void shm_exit_ns(struct ipc_namespace *ns) { }
52#endif
73ea4130 53
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54/*
55 * Structure that holds the parameters needed by the ipc operations
56 * (see after)
57 */
58struct ipc_params {
59 key_t key;
60 int flg;
61 union {
62 size_t size; /* for shared memories */
63 int nsems; /* for semaphores */
64 } u; /* holds the getnew() specific param */
65};
66
67/*
68 * Structure that holds some ipc operations. This structure is used to unify
69 * the calls to sys_msgget(), sys_semget(), sys_shmget()
70 * . routine to call to create a new ipc object. Can be one of newque,
71 * newary, newseg
f4566f04 72 * . routine to call to check permissions for a new ipc object.
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73 * Can be one of security_msg_associate, security_sem_associate,
74 * security_shm_associate
75 * . routine to call for an extra check if needed
76 */
77struct ipc_ops {
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PM
78 int (*getnew)(struct ipc_namespace *, struct ipc_params *);
79 int (*associate)(struct kern_ipc_perm *, int);
80 int (*more_checks)(struct kern_ipc_perm *, struct ipc_params *);
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81};
82
ae781774 83struct seq_file;
ed2ddbf8 84struct ipc_ids;
7d69a1f4 85
0cfb6aee 86int ipc_init_ids(struct ipc_ids *);
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87#ifdef CONFIG_PROC_FS
88void __init ipc_init_proc_interface(const char *path, const char *header,
73ea4130 89 int ids, int (*show)(struct seq_file *, void *));
03f1fc09 90struct pid_namespace *ipc_seq_pid_ns(struct seq_file *);
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91#else
92#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
93#endif
1da177e4 94
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95#define IPC_SEM_IDS 0
96#define IPC_MSG_IDS 1
97#define IPC_SHM_IDS 2
98
ce621f5b 99#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
03f59566 100#define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER)
daf948c7 101#define IPCID_SEQ_MAX min_t(int, INT_MAX/SEQ_MULTIPLIER, USHRT_MAX)
ce621f5b 102
d9a605e4 103/* must be called with ids->rwsem acquired for writing */
7ca7e564 104int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
3e148c79 105
1da177e4 106/* must be called with both locks acquired. */
7ca7e564 107void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
1da177e4 108
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109/* must be called with both locks acquired. */
110void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *);
111
f4566f04 112/* must be called with ipcp locked */
b0e77598 113int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
1da177e4 114
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DB
115/**
116 * ipc_get_maxid - get the last assigned id
117 * @ids: ipc identifier set
118 *
119 * Called with ipc_ids.rwsem held for reading.
120 */
121static inline int ipc_get_maxid(struct ipc_ids *ids)
122{
123 if (ids->in_use == 0)
124 return -1;
125
126 if (ids->in_use == IPCMNI)
127 return IPCMNI - 1;
128
129 return ids->max_id;
130}
131
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132/*
133 * For allocation that need to be freed by RCU.
134 * Objects are reference counted, they start with reference count 1.
135 * getref increases the refcount, the putref call that reduces the recount
136 * to 0 schedules the rcu destruction. Caller must guarantee locking.
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137 *
138 * refcount is initialized by ipc_addid(), before that point call_rcu()
139 * must be used.
1da177e4 140 */
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141int ipc_rcu_getref(struct kern_ipc_perm *ptr);
142void ipc_rcu_putref(struct kern_ipc_perm *ptr,
143 void (*func)(struct rcu_head *head));
1da177e4 144
023a5355 145struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
55b7ae50 146struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);
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147
148void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
149void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
1efdb69b 150int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
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151struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns,
152 struct ipc_ids *ids, int id, int cmd,
153 struct ipc64_perm *perm, int extra_perm);
1da177e4 154
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155static inline void ipc_update_pid(struct pid **pos, struct pid *pid)
156{
157 struct pid *old = *pos;
158 if (old != pid) {
159 *pos = get_pid(pid);
160 put_pid(old);
161 }
162}
163
c1d7e01d 164#ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
46c0a8ca 165/* On IA-64, we always use the "64-bit version" of the IPC structures. */
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166# define ipc_parse_version(cmd) IPC_64
167#else
239521f3 168int ipc_parse_version(int *cmd);
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169#endif
170
171extern void free_msg(struct msg_msg *msg);
4e9b45a1 172extern struct msg_msg *load_msg(const void __user *src, size_t len);
4a674f34 173extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
4e9b45a1 174extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);
7748dbfa 175
1b531f21 176static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
023a5355 177{
7bb4deff 178 return uid / SEQ_MULTIPLIER != ipcp->seq;
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179}
180
1ca7003a 181static inline void ipc_lock_object(struct kern_ipc_perm *perm)
023a5355 182{
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183 spin_lock(&perm->lock);
184}
185
1ca7003a 186static inline void ipc_unlock_object(struct kern_ipc_perm *perm)
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187{
188 spin_unlock(&perm->lock);
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189}
190
1ca7003a 191static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm)
16df3674 192{
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193 assert_spin_locked(&perm->lock);
194}
195
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196static inline void ipc_unlock(struct kern_ipc_perm *perm)
197{
cf9d5d78 198 ipc_unlock_object(perm);
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199 rcu_read_unlock();
200}
201
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202/*
203 * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths
204 * where the respective ipc_ids.rwsem is not being held down.
205 * Checks whether the ipc object is still around or if it's gone already, as
206 * ipc_rmid() may have already freed the ID while the ipc lock was spinning.
207 * Needs to be called with kern_ipc_perm.lock held -- exception made for one
208 * checkpoint case at sys_semtimedop() as noted in code commentary.
209 */
210static inline bool ipc_valid_object(struct kern_ipc_perm *perm)
211{
72a8ff2f 212 return !perm->deleted;
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213}
214
4d2bff5e 215struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
b2d75cdd 216int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
eb66ec44 217 const struct ipc_ops *ops, struct ipc_params *params);
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218void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
219 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
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220
221#ifdef CONFIG_COMPAT
222#include <linux/compat.h>
223struct compat_ipc_perm {
224 key_t key;
225 __compat_uid_t uid;
226 __compat_gid_t gid;
227 __compat_uid_t cuid;
228 __compat_gid_t cgid;
229 compat_mode_t mode;
230 unsigned short seq;
231};
232
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AV
233void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *);
234void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *);
235int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *);
236int get_compat_ipc64_perm(struct ipc64_perm *,
237 struct compat_ipc64_perm __user *);
238
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AV
239static inline int compat_ipc_parse_version(int *cmd)
240{
241#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
242 int version = *cmd & IPC_64;
243 *cmd &= ~IPC_64;
244 return version;
245#else
246 return IPC_64;
247#endif
248}
249#endif
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250
251/* for __ARCH_WANT_SYS_IPC */
252long ksys_semtimedop(int semid, struct sembuf __user *tsops,
253 unsigned int nsops,
21fc538d 254 const struct __kernel_timespec __user *timeout);
69894718 255long ksys_semget(key_t key, int nsems, int semflg);
d969c6fa 256long ksys_semctl(int semid, int semnum, int cmd, unsigned long arg);
3d65661a 257long ksys_msgget(key_t key, int msgflg);
e340db56 258long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf);
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259long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
260 long msgtyp, int msgflg);
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261long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
262 int msgflg);
65749e0b 263long ksys_shmget(key_t key, size_t size, int shmflg);
da1e2744 264long ksys_shmdt(char __user *shmaddr);
c84d0791 265long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf);
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266
267/* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */
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268long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems,
269 unsigned int nsops,
270 const struct compat_timespec __user *timeout);
b0d17578 271#ifdef CONFIG_COMPAT
d969c6fa 272long compat_ksys_semctl(int semid, int semnum, int cmd, int arg);
e340db56 273long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr);
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274long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
275 compat_long_t msgtyp, int msgflg);
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276long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
277 compat_ssize_t msgsz, int msgflg);
c84d0791 278long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr);
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279#endif /* CONFIG_COMPAT */
280
1da177e4 281#endif