Merge tag 'mm-stable-2024-05-17-19-19' of git://git.kernel.org/pub/scm/linux/kernel...
[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
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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>
f551103c 17#include <linux/pid.h>
7ca7e564 18
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19/*
20 * The IPC ID contains 2 separate numbers - index and sequence number.
21 * By default,
22 * bits 0-14: index (32k, 15 bits)
23 * bits 15-30: sequence number (64k, 16 bits)
24 *
25 * When IPCMNI extension mode is turned on, the composition changes:
26 * bits 0-23: index (16M, 24 bits)
27 * bits 24-30: sequence number (128, 7 bits)
28 */
29#define IPCMNI_SHIFT 15
30#define IPCMNI_EXTEND_SHIFT 24
99db46ea 31#define IPCMNI_EXTEND_MIN_CYCLE (RADIX_TREE_MAP_SIZE * RADIX_TREE_MAP_SIZE)
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32#define IPCMNI (1 << IPCMNI_SHIFT)
33#define IPCMNI_EXTEND (1 << IPCMNI_EXTEND_SHIFT)
34
35#ifdef CONFIG_SYSVIPC_SYSCTL
36extern int ipc_mni;
37extern int ipc_mni_shift;
99db46ea 38extern int ipc_min_cycle;
5ac893b8 39
3278a2c2 40#define ipcmni_seq_shift() ipc_mni_shift
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41#define IPCMNI_IDX_MASK ((1 << ipc_mni_shift) - 1)
42
43#else /* CONFIG_SYSVIPC_SYSCTL */
44
45#define ipc_mni IPCMNI
99db46ea 46#define ipc_min_cycle ((int)RADIX_TREE_MAP_SIZE)
3278a2c2 47#define ipcmni_seq_shift() IPCMNI_SHIFT
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48#define IPCMNI_IDX_MASK ((1 << IPCMNI_SHIFT) - 1)
49#endif /* CONFIG_SYSVIPC_SYSCTL */
1da177e4 50
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51void sem_init(void);
52void msg_init(void);
239521f3 53void shm_init(void);
1da177e4 54
ae5e1b22 55struct ipc_namespace;
03f1fc09 56struct pid_namespace;
ae5e1b22 57
614b84cf 58#ifdef CONFIG_POSIX_MQUEUE
7eafd7c7 59extern void mq_clear_sbinfo(struct ipc_namespace *ns);
614b84cf 60#else
7eafd7c7 61static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
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SH
62#endif
63
64#ifdef CONFIG_SYSVIPC
eae04d25 65void sem_init_ns(struct ipc_namespace *ns);
72d1e611 66int msg_init_ns(struct ipc_namespace *ns);
eae04d25 67void shm_init_ns(struct ipc_namespace *ns);
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68
69void sem_exit_ns(struct ipc_namespace *ns);
70void msg_exit_ns(struct ipc_namespace *ns);
71void shm_exit_ns(struct ipc_namespace *ns);
614b84cf 72#else
eae04d25 73static inline void sem_init_ns(struct ipc_namespace *ns) { }
72d1e611 74static inline int msg_init_ns(struct ipc_namespace *ns) { return 0; }
eae04d25 75static inline void shm_init_ns(struct ipc_namespace *ns) { }
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76
77static inline void sem_exit_ns(struct ipc_namespace *ns) { }
78static inline void msg_exit_ns(struct ipc_namespace *ns) { }
79static inline void shm_exit_ns(struct ipc_namespace *ns) { }
80#endif
73ea4130 81
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82/*
83 * Structure that holds the parameters needed by the ipc operations
84 * (see after)
85 */
86struct ipc_params {
87 key_t key;
88 int flg;
89 union {
90 size_t size; /* for shared memories */
91 int nsems; /* for semaphores */
92 } u; /* holds the getnew() specific param */
93};
94
95/*
96 * Structure that holds some ipc operations. This structure is used to unify
97 * the calls to sys_msgget(), sys_semget(), sys_shmget()
98 * . routine to call to create a new ipc object. Can be one of newque,
99 * newary, newseg
f4566f04 100 * . routine to call to check permissions for a new ipc object.
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101 * Can be one of security_msg_associate, security_sem_associate,
102 * security_shm_associate
103 * . routine to call for an extra check if needed
104 */
105struct ipc_ops {
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106 int (*getnew)(struct ipc_namespace *, struct ipc_params *);
107 int (*associate)(struct kern_ipc_perm *, int);
108 int (*more_checks)(struct kern_ipc_perm *, struct ipc_params *);
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109};
110
ae781774 111struct seq_file;
ed2ddbf8 112struct ipc_ids;
7d69a1f4 113
eae04d25 114void ipc_init_ids(struct ipc_ids *ids);
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115#ifdef CONFIG_PROC_FS
116void __init ipc_init_proc_interface(const char *path, const char *header,
73ea4130 117 int ids, int (*show)(struct seq_file *, void *));
03f1fc09 118struct pid_namespace *ipc_seq_pid_ns(struct seq_file *);
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119#else
120#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
121#endif
1da177e4 122
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123#define IPC_SEM_IDS 0
124#define IPC_MSG_IDS 1
125#define IPC_SHM_IDS 2
126
5ac893b8 127#define ipcid_to_idx(id) ((id) & IPCMNI_IDX_MASK)
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128#define ipcid_to_seqx(id) ((id) >> ipcmni_seq_shift())
129#define ipcid_seq_max() (INT_MAX >> ipcmni_seq_shift())
ce621f5b 130
d9a605e4 131/* must be called with ids->rwsem acquired for writing */
7ca7e564 132int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
3e148c79 133
1da177e4 134/* must be called with both locks acquired. */
7ca7e564 135void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
1da177e4 136
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137/* must be called with both locks acquired. */
138void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *);
139
f4566f04 140/* must be called with ipcp locked */
b0e77598 141int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
1da177e4 142
15df03c8 143/**
27c331a1 144 * ipc_get_maxidx - get the highest assigned index
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145 * @ids: ipc identifier set
146 *
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147 * The function returns the highest assigned index for @ids. The function
148 * doesn't scan the idr tree, it uses a cached value.
149 *
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150 * Called with ipc_ids.rwsem held for reading.
151 */
27c331a1 152static inline int ipc_get_maxidx(struct ipc_ids *ids)
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153{
154 if (ids->in_use == 0)
155 return -1;
156
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157 if (ids->in_use == ipc_mni)
158 return ipc_mni - 1;
15df03c8 159
27c331a1 160 return ids->max_idx;
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161}
162
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163/*
164 * For allocation that need to be freed by RCU.
165 * Objects are reference counted, they start with reference count 1.
166 * getref increases the refcount, the putref call that reduces the recount
167 * to 0 schedules the rcu destruction. Caller must guarantee locking.
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168 *
169 * refcount is initialized by ipc_addid(), before that point call_rcu()
170 * must be used.
1da177e4 171 */
2a9d6481 172bool ipc_rcu_getref(struct kern_ipc_perm *ptr);
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173void ipc_rcu_putref(struct kern_ipc_perm *ptr,
174 void (*func)(struct rcu_head *head));
1da177e4 175
55b7ae50 176struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);
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177
178void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
179void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
1efdb69b 180int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
4241c1a3 181struct kern_ipc_perm *ipcctl_obtain_check(struct ipc_namespace *ns,
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182 struct ipc_ids *ids, int id, int cmd,
183 struct ipc64_perm *perm, int extra_perm);
1da177e4 184
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185static inline void ipc_update_pid(struct pid **pos, struct pid *pid)
186{
187 struct pid *old = *pos;
188 if (old != pid) {
189 *pos = get_pid(pid);
190 put_pid(old);
191 }
192}
193
275f2214 194#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
239521f3 195int ipc_parse_version(int *cmd);
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196#endif
197
198extern void free_msg(struct msg_msg *msg);
4e9b45a1 199extern struct msg_msg *load_msg(const void __user *src, size_t len);
4a674f34 200extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
4e9b45a1 201extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);
7748dbfa 202
27c331a1 203static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int id)
023a5355 204{
27c331a1 205 return ipcid_to_seqx(id) != ipcp->seq;
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206}
207
1ca7003a 208static inline void ipc_lock_object(struct kern_ipc_perm *perm)
023a5355 209{
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210 spin_lock(&perm->lock);
211}
212
1ca7003a 213static inline void ipc_unlock_object(struct kern_ipc_perm *perm)
023a5355
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214{
215 spin_unlock(&perm->lock);
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216}
217
1ca7003a 218static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm)
16df3674 219{
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220 assert_spin_locked(&perm->lock);
221}
222
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223static inline void ipc_unlock(struct kern_ipc_perm *perm)
224{
cf9d5d78 225 ipc_unlock_object(perm);
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226 rcu_read_unlock();
227}
228
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229/*
230 * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths
231 * where the respective ipc_ids.rwsem is not being held down.
232 * Checks whether the ipc object is still around or if it's gone already, as
233 * ipc_rmid() may have already freed the ID while the ipc lock was spinning.
234 * Needs to be called with kern_ipc_perm.lock held -- exception made for one
235 * checkpoint case at sys_semtimedop() as noted in code commentary.
236 */
237static inline bool ipc_valid_object(struct kern_ipc_perm *perm)
238{
72a8ff2f 239 return !perm->deleted;
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RA
240}
241
4d2bff5e 242struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
b2d75cdd 243int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
eb66ec44 244 const struct ipc_ops *ops, struct ipc_params *params);
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245void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
246 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
553f770e 247
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248static inline int sem_check_semmni(struct ipc_namespace *ns) {
249 /*
5ac893b8 250 * Check semmni range [0, ipc_mni]
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251 * semmni is the last element of sem_ctls[4] array
252 */
5ac893b8 253 return ((ns->sem_ctls[3] < 0) || (ns->sem_ctls[3] > ipc_mni))
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254 ? -ERANGE : 0;
255}
256
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257#ifdef CONFIG_COMPAT
258#include <linux/compat.h>
259struct compat_ipc_perm {
260 key_t key;
261 __compat_uid_t uid;
262 __compat_gid_t gid;
263 __compat_uid_t cuid;
264 __compat_gid_t cgid;
265 compat_mode_t mode;
266 unsigned short seq;
267};
268
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AV
269void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *);
270void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *);
271int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *);
272int get_compat_ipc64_perm(struct ipc64_perm *,
273 struct compat_ipc64_perm __user *);
274
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AV
275static inline int compat_ipc_parse_version(int *cmd)
276{
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277 int version = *cmd & IPC_64;
278 *cmd &= ~IPC_64;
279 return version;
553f770e 280}
41f4f0e2 281
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282long compat_ksys_old_semctl(int semid, int semnum, int cmd, int arg);
283long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr);
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284long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
285 compat_long_t msgtyp, int msgflg);
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286long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
287 compat_ssize_t msgsz, int msgflg);
275f2214 288long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr);
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289
290#endif
41f4f0e2 291
1da177e4 292#endif