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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/ipc/util.h
3 * Copyright (C) 1999 Christoph Rohland
4 *
Christian Kujau624dffc2006-01-15 02:43:54 +01005 * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>
Kirill Korotaev73ea4132006-10-02 02:18:20 -07006 * namespaces support. 2006 OpenVZ, SWsoft Inc.
7 * Pavel Emelianov <xemul@openvz.org>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 */
9
10#ifndef _IPC_UTIL_H
11#define _IPC_UTIL_H
12
Johannes Weiner232086b2009-06-20 02:23:29 +020013#include <linux/unistd.h>
Nadia Derbey023a5352007-10-18 23:40:51 -070014#include <linux/err.h>
Nadia Derbey7ca7e562007-10-18 23:40:48 -070015
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#define SEQ_MULTIPLIER (IPCMNI)
17
Manfred Spraul239521f2014-01-27 17:07:04 -080018void sem_init(void);
19void msg_init(void);
20void shm_init(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -070021
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080022struct ipc_namespace;
23
Serge E. Hallyn614b84c2009-04-06 19:01:08 -070024#ifdef CONFIG_POSIX_MQUEUE
Serge E. Hallyn7eafd7c2009-04-06 19:01:10 -070025extern void mq_clear_sbinfo(struct ipc_namespace *ns);
26extern void mq_put_mnt(struct ipc_namespace *ns);
Serge E. Hallyn614b84c2009-04-06 19:01:08 -070027#else
Serge E. Hallyn7eafd7c2009-04-06 19:01:10 -070028static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
29static inline void mq_put_mnt(struct ipc_namespace *ns) { }
Serge E. Hallyn614b84c2009-04-06 19:01:08 -070030#endif
31
32#ifdef CONFIG_SYSVIPC
Pierre Peiffered2ddbf2008-02-08 04:18:57 -080033void sem_init_ns(struct ipc_namespace *ns);
34void msg_init_ns(struct ipc_namespace *ns);
35void shm_init_ns(struct ipc_namespace *ns);
Kirill Korotaev73ea4132006-10-02 02:18:20 -070036
37void sem_exit_ns(struct ipc_namespace *ns);
38void msg_exit_ns(struct ipc_namespace *ns);
39void shm_exit_ns(struct ipc_namespace *ns);
Serge E. Hallyn614b84c2009-04-06 19:01:08 -070040#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
Kirill Korotaev73ea4132006-10-02 02:18:20 -070049
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -070050struct 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
Nadia Derbey7748dbf2007-10-18 23:40:49 -070057/*
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
Nadia Derbeyf4566f02007-10-18 23:40:53 -070075 * . routine to call to check permissions for a new ipc object.
Nadia Derbey7748dbf2007-10-18 23:40:49 -070076 * 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 {
Paul McQuade46c0a8c2014-06-06 14:37:37 -070081 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 *);
Nadia Derbey7748dbf2007-10-18 23:40:49 -070084};
85
Mike Waychisonae781772005-09-06 15:17:09 -070086struct seq_file;
Pierre Peiffered2ddbf2008-02-08 04:18:57 -080087struct ipc_ids;
Cedric Le Goater7d69a1f2007-07-15 23:40:58 -070088
Nadia Derbey7ca7e562007-10-18 23:40:48 -070089void ipc_init_ids(struct ipc_ids *);
Mike Waychisonae781772005-09-06 15:17:09 -070090#ifdef CONFIG_PROC_FS
91void __init ipc_init_proc_interface(const char *path, const char *header,
Kirill Korotaev73ea4132006-10-02 02:18:20 -070092 int ids, int (*show)(struct seq_file *, void *));
Mike Waychisonae781772005-09-06 15:17:09 -070093#else
94#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
95#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
Kirill Korotaev73ea4132006-10-02 02:18:20 -070097#define IPC_SEM_IDS 0
98#define IPC_MSG_IDS 1
99#define IPC_SHM_IDS 2
100
Nadia Derbeyce621f52007-10-18 23:40:52 -0700101#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
Stanislav Kinsbursky03f59562013-01-04 15:34:50 -0800102#define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER)
Davidlohr Buesodaf948c2014-01-27 17:07:09 -0800103#define IPCID_SEQ_MAX min_t(int, INT_MAX/SEQ_MULTIPLIER, USHRT_MAX)
Nadia Derbeyce621f52007-10-18 23:40:52 -0700104
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700105/* must be called with ids->rwsem acquired for writing */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700106int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
Nadia Derbey3e148c72007-10-18 23:40:54 -0700107
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700108/* must be called with ids->rwsem acquired for reading */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700109int ipc_get_maxid(struct ipc_ids *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110
111/* must be called with both locks acquired. */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700112void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700114/* must be called with ipcp locked */
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700115int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116
117/* for rare, potentially huge allocations.
118 * both function can sleep
119 */
Manfred Spraul239521f2014-01-27 17:07:04 -0800120void *ipc_alloc(int size);
Tetsuo Handa1d5cfdb2016-01-22 15:11:02 -0800121void ipc_free(void *ptr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122
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 */
Manfred Spraul239521f2014-01-27 17:07:04 -0800129void *ipc_rcu_alloc(int size);
Rik van Riel6062a8d2013-04-30 19:15:44 -0700130int ipc_rcu_getref(void *ptr);
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700131void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head));
132void ipc_rcu_free(struct rcu_head *head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133
Nadia Derbey023a5352007-10-18 23:40:51 -0700134struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
Davidlohr Bueso55b7ae52015-06-30 14:58:42 -0700135struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
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);
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800139int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
Davidlohr Bueso444d0f62013-04-30 19:15:24 -0700140struct 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);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143
Will Deaconc1d7e012012-07-30 14:42:46 -0700144#ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
Paul McQuade46c0a8c2014-06-06 14:37:37 -0700145/* On IA-64, we always use the "64-bit version" of the IPC structures. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146# define ipc_parse_version(cmd) IPC_64
147#else
Manfred Spraul239521f2014-01-27 17:07:04 -0800148int ipc_parse_version(int *cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149#endif
150
151extern void free_msg(struct msg_msg *msg);
Mathias Krause4e9b45a2013-11-12 15:11:47 -0800152extern struct msg_msg *load_msg(const void __user *src, size_t len);
Stanislav Kinsbursky4a674f32013-01-04 15:34:55 -0800153extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
Mathias Krause4e9b45a2013-11-12 15:11:47 -0800154extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700155
Nadia Derbeyb6b337a2008-04-29 01:00:42 -0700156extern void recompute_msgmni(struct ipc_namespace *);
157
Nadia Derbey1b531f22007-10-18 23:40:55 -0700158static inline int ipc_buildid(int id, int seq)
Nadia Derbey28028312007-10-18 23:40:52 -0700159{
160 return SEQ_MULTIPLIER * seq + id;
161}
162
Nadia Derbey1b531f22007-10-18 23:40:55 -0700163static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
Nadia Derbey023a5352007-10-18 23:40:51 -0700164{
Davidlohr Bueso7bb4def2013-04-30 19:15:14 -0700165 return uid / SEQ_MULTIPLIER != ipcp->seq;
Nadia Derbey023a5352007-10-18 23:40:51 -0700166}
167
Davidlohr Bueso1ca70032013-07-08 16:01:10 -0700168static 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
Nadia Derbey023a5352007-10-18 23:40:51 -0700183static inline void ipc_unlock(struct kern_ipc_perm *perm)
184{
Davidlohr Buesocf9d5d72013-07-08 16:01:11 -0700185 ipc_unlock_object(perm);
Nadia Derbey023a5352007-10-18 23:40:51 -0700186 rcu_read_unlock();
187}
188
Rafael Aquini0f3d2b02014-01-27 17:07:01 -0800189/*
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{
Rafael Aquini72a8ff22014-01-27 17:07:02 -0800199 return !perm->deleted;
Rafael Aquini0f3d2b02014-01-27 17:07:01 -0800200}
201
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700202struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
Pavel Emelyanovb2d75cd2008-02-08 04:18:54 -0800203int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
Mathias Krauseeb66ec42014-06-06 14:37:36 -0700204 const struct ipc_ops *ops, struct ipc_params *params);
Alexey Dobriyan665c7742009-06-17 16:27:57 -0700205void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
206 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207#endif