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1/*
2 * linux/ipc/util.h
3 * Copyright (C) 1999 Christoph Rohland
4 *
5 * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>
6 * namespaces support. 2006 OpenVZ, SWsoft Inc.
7 * Pavel Emelianov <xemul@openvz.org>
8 */
9
10#ifndef _IPC_UTIL_H
11#define _IPC_UTIL_H
12
13#include <linux/unistd.h>
14#include <linux/err.h>
15
16#define SEQ_MULTIPLIER (IPCMNI)
17
18void sem_init(void);
19void msg_init(void);
20void shm_init(void);
21
22struct ipc_namespace;
23
24#ifdef CONFIG_POSIX_MQUEUE
25extern void mq_clear_sbinfo(struct ipc_namespace *ns);
26extern void mq_put_mnt(struct ipc_namespace *ns);
27#else
28static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
29static inline void mq_put_mnt(struct ipc_namespace *ns) { }
30#endif
31
32#ifdef CONFIG_SYSVIPC
33void sem_init_ns(struct ipc_namespace *ns);
34void msg_init_ns(struct ipc_namespace *ns);
35void shm_init_ns(struct ipc_namespace *ns);
36
37void sem_exit_ns(struct ipc_namespace *ns);
38void msg_exit_ns(struct ipc_namespace *ns);
39void shm_exit_ns(struct ipc_namespace *ns);
40#else
41static inline void sem_init_ns(struct ipc_namespace *ns) { }
42static inline void msg_init_ns(struct ipc_namespace *ns) { }
43static inline void shm_init_ns(struct ipc_namespace *ns) { }
44
45static inline void sem_exit_ns(struct ipc_namespace *ns) { }
46static inline void msg_exit_ns(struct ipc_namespace *ns) { }
47static inline void shm_exit_ns(struct ipc_namespace *ns) { }
48#endif
49
50struct ipc_rcu {
51 struct rcu_head rcu;
52 atomic_t refcount;
53} ____cacheline_aligned_in_smp;
54
55#define ipc_rcu_to_struct(p) ((void *)(p+1))
56
57/*
58 * Structure that holds the parameters needed by the ipc operations
59 * (see after)
60 */
61struct ipc_params {
62 key_t key;
63 int flg;
64 union {
65 size_t size; /* for shared memories */
66 int nsems; /* for semaphores */
67 } u; /* holds the getnew() specific param */
68};
69
70/*
71 * Structure that holds some ipc operations. This structure is used to unify
72 * the calls to sys_msgget(), sys_semget(), sys_shmget()
73 * . routine to call to create a new ipc object. Can be one of newque,
74 * newary, newseg
75 * . routine to call to check permissions for a new ipc object.
76 * Can be one of security_msg_associate, security_sem_associate,
77 * security_shm_associate
78 * . routine to call for an extra check if needed
79 */
80struct ipc_ops {
81 int (*getnew)(struct ipc_namespace *, struct ipc_params *);
82 int (*associate)(struct kern_ipc_perm *, int);
83 int (*more_checks)(struct kern_ipc_perm *, struct ipc_params *);
84};
85
86struct seq_file;
87struct ipc_ids;
88
89void ipc_init_ids(struct ipc_ids *);
90#ifdef CONFIG_PROC_FS
91void __init ipc_init_proc_interface(const char *path, const char *header,
92 int ids, int (*show)(struct seq_file *, void *));
93#else
94#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
95#endif
96
97#define IPC_SEM_IDS 0
98#define IPC_MSG_IDS 1
99#define IPC_SHM_IDS 2
100
101#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
102#define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER)
103#define IPCID_SEQ_MAX min_t(int, INT_MAX/SEQ_MULTIPLIER, USHRT_MAX)
104
105/* must be called with ids->rwsem acquired for writing */
106int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
107
108/* must be called with ids->rwsem acquired for reading */
109int ipc_get_maxid(struct ipc_ids *);
110
111/* must be called with both locks acquired. */
112void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
113
114/* must be called with ipcp locked */
115int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
116
117/* for rare, potentially huge allocations.
118 * both function can sleep
119 */
120void *ipc_alloc(int size);
121void ipc_free(void *ptr);
122
123/*
124 * For allocation that need to be freed by RCU.
125 * Objects are reference counted, they start with reference count 1.
126 * getref increases the refcount, the putref call that reduces the recount
127 * to 0 schedules the rcu destruction. Caller must guarantee locking.
128 */
129void *ipc_rcu_alloc(int size);
130int ipc_rcu_getref(void *ptr);
131void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head));
132void ipc_rcu_free(struct rcu_head *head);
133
134struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
135struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);
136
137void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
138void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
139int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
140struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns,
141 struct ipc_ids *ids, int id, int cmd,
142 struct ipc64_perm *perm, int extra_perm);
143
144#ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
145/* On IA-64, we always use the "64-bit version" of the IPC structures. */
146# define ipc_parse_version(cmd) IPC_64
147#else
148int ipc_parse_version(int *cmd);
149#endif
150
151extern void free_msg(struct msg_msg *msg);
152extern struct msg_msg *load_msg(const void __user *src, size_t len);
153extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
154extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);
155
156extern void recompute_msgmni(struct ipc_namespace *);
157
158static inline int ipc_buildid(int id, int seq)
159{
160 return SEQ_MULTIPLIER * seq + id;
161}
162
163static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
164{
165 return uid / SEQ_MULTIPLIER != ipcp->seq;
166}
167
168static inline void ipc_lock_object(struct kern_ipc_perm *perm)
169{
170 spin_lock(&perm->lock);
171}
172
173static inline void ipc_unlock_object(struct kern_ipc_perm *perm)
174{
175 spin_unlock(&perm->lock);
176}
177
178static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm)
179{
180 assert_spin_locked(&perm->lock);
181}
182
183static inline void ipc_unlock(struct kern_ipc_perm *perm)
184{
185 ipc_unlock_object(perm);
186 rcu_read_unlock();
187}
188
189/*
190 * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths
191 * where the respective ipc_ids.rwsem is not being held down.
192 * Checks whether the ipc object is still around or if it's gone already, as
193 * ipc_rmid() may have already freed the ID while the ipc lock was spinning.
194 * Needs to be called with kern_ipc_perm.lock held -- exception made for one
195 * checkpoint case at sys_semtimedop() as noted in code commentary.
196 */
197static inline bool ipc_valid_object(struct kern_ipc_perm *perm)
198{
199 return !perm->deleted;
200}
201
202struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
203int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
204 const struct ipc_ops *ops, struct ipc_params *params);
205void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
206 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
207#endif
1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * linux/ipc/util.h
4 * Copyright (C) 1999 Christoph Rohland
5 *
6 * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>
7 * namespaces support. 2006 OpenVZ, SWsoft Inc.
8 * Pavel Emelianov <xemul@openvz.org>
9 */
10
11#ifndef _IPC_UTIL_H
12#define _IPC_UTIL_H
13
14#include <linux/unistd.h>
15#include <linux/err.h>
16#include <linux/ipc_namespace.h>
17
18#define IPCMNI 32768 /* <= MAX_INT limit for ipc arrays (including sysctl changes) */
19#define SEQ_MULTIPLIER (IPCMNI)
20
21int sem_init(void);
22int msg_init(void);
23void shm_init(void);
24
25struct ipc_namespace;
26struct pid_namespace;
27
28#ifdef CONFIG_POSIX_MQUEUE
29extern void mq_clear_sbinfo(struct ipc_namespace *ns);
30extern void mq_put_mnt(struct ipc_namespace *ns);
31#else
32static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
33static inline void mq_put_mnt(struct ipc_namespace *ns) { }
34#endif
35
36#ifdef CONFIG_SYSVIPC
37int sem_init_ns(struct ipc_namespace *ns);
38int msg_init_ns(struct ipc_namespace *ns);
39int shm_init_ns(struct ipc_namespace *ns);
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);
44#else
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; }
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
53
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
72 * . routine to call to check permissions for a new ipc object.
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 {
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 *);
81};
82
83struct seq_file;
84struct ipc_ids;
85
86int ipc_init_ids(struct ipc_ids *);
87#ifdef CONFIG_PROC_FS
88void __init ipc_init_proc_interface(const char *path, const char *header,
89 int ids, int (*show)(struct seq_file *, void *));
90struct pid_namespace *ipc_seq_pid_ns(struct seq_file *);
91#else
92#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
93#endif
94
95#define IPC_SEM_IDS 0
96#define IPC_MSG_IDS 1
97#define IPC_SHM_IDS 2
98
99#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
100#define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER)
101#define IPCID_SEQ_MAX min_t(int, INT_MAX/SEQ_MULTIPLIER, USHRT_MAX)
102
103/* must be called with ids->rwsem acquired for writing */
104int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
105
106/* must be called with both locks acquired. */
107void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
108
109/* must be called with both locks acquired. */
110void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *);
111
112/* must be called with ipcp locked */
113int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
114
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
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.
137 *
138 * refcount is initialized by ipc_addid(), before that point call_rcu()
139 * must be used.
140 */
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));
144
145struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
146struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);
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);
150int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
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);
154
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
164#ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
165/* On IA-64, we always use the "64-bit version" of the IPC structures. */
166# define ipc_parse_version(cmd) IPC_64
167#else
168int ipc_parse_version(int *cmd);
169#endif
170
171extern void free_msg(struct msg_msg *msg);
172extern struct msg_msg *load_msg(const void __user *src, size_t len);
173extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
174extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);
175
176static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
177{
178 return uid / SEQ_MULTIPLIER != ipcp->seq;
179}
180
181static inline void ipc_lock_object(struct kern_ipc_perm *perm)
182{
183 spin_lock(&perm->lock);
184}
185
186static inline void ipc_unlock_object(struct kern_ipc_perm *perm)
187{
188 spin_unlock(&perm->lock);
189}
190
191static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm)
192{
193 assert_spin_locked(&perm->lock);
194}
195
196static inline void ipc_unlock(struct kern_ipc_perm *perm)
197{
198 ipc_unlock_object(perm);
199 rcu_read_unlock();
200}
201
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{
212 return !perm->deleted;
213}
214
215struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
216int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
217 const struct ipc_ops *ops, struct ipc_params *params);
218void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
219 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
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
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
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
250
251/* for __ARCH_WANT_SYS_IPC */
252long ksys_semtimedop(int semid, struct sembuf __user *tsops,
253 unsigned int nsops,
254 const struct timespec __user *timeout);
255long ksys_semget(key_t key, int nsems, int semflg);
256long ksys_semctl(int semid, int semnum, int cmd, unsigned long arg);
257long ksys_msgget(key_t key, int msgflg);
258long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf);
259long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
260 long msgtyp, int msgflg);
261long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
262 int msgflg);
263long ksys_shmget(key_t key, size_t size, int shmflg);
264long ksys_shmdt(char __user *shmaddr);
265long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf);
266
267/* for CONFIG_ARCH_WANT_OLD_COMPAT_IPC */
268#ifdef CONFIG_COMPAT
269long compat_ksys_semtimedop(int semid, struct sembuf __user *tsems,
270 unsigned int nsops,
271 const struct compat_timespec __user *timeout);
272long compat_ksys_semctl(int semid, int semnum, int cmd, int arg);
273long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr);
274long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
275 compat_long_t msgtyp, int msgflg);
276long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
277 compat_ssize_t msgsz, int msgflg);
278long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr);
279#endif /* CONFIG_COMPAT */
280
281#endif