blob: cdb966aebe0716e8375617431d5734ed45aa639f [file] [log] [blame]
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
Nadia Derbey023a5352007-10-18 23:40:51 -070013#include <linux/err.h>
Nadia Derbey7ca7e562007-10-18 23:40:48 -070014
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#define SEQ_MULTIPLIER (IPCMNI)
16
17void sem_init (void);
18void msg_init (void);
19void shm_init (void);
20
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080021struct ipc_namespace;
22
Pierre Peiffered2ddbf2008-02-08 04:18:57 -080023void sem_init_ns(struct ipc_namespace *ns);
24void msg_init_ns(struct ipc_namespace *ns);
25void shm_init_ns(struct ipc_namespace *ns);
Kirill Korotaev73ea4132006-10-02 02:18:20 -070026
27void sem_exit_ns(struct ipc_namespace *ns);
28void msg_exit_ns(struct ipc_namespace *ns);
29void shm_exit_ns(struct ipc_namespace *ns);
30
Nadia Derbey7748dbf2007-10-18 23:40:49 -070031/*
32 * Structure that holds the parameters needed by the ipc operations
33 * (see after)
34 */
35struct ipc_params {
36 key_t key;
37 int flg;
38 union {
39 size_t size; /* for shared memories */
40 int nsems; /* for semaphores */
41 } u; /* holds the getnew() specific param */
42};
43
44/*
45 * Structure that holds some ipc operations. This structure is used to unify
46 * the calls to sys_msgget(), sys_semget(), sys_shmget()
47 * . routine to call to create a new ipc object. Can be one of newque,
48 * newary, newseg
Nadia Derbeyf4566f02007-10-18 23:40:53 -070049 * . routine to call to check permissions for a new ipc object.
Nadia Derbey7748dbf2007-10-18 23:40:49 -070050 * Can be one of security_msg_associate, security_sem_associate,
51 * security_shm_associate
52 * . routine to call for an extra check if needed
53 */
54struct ipc_ops {
55 int (*getnew) (struct ipc_namespace *, struct ipc_params *);
Nadia Derbey03f02c72007-10-18 23:40:51 -070056 int (*associate) (struct kern_ipc_perm *, int);
57 int (*more_checks) (struct kern_ipc_perm *, struct ipc_params *);
Nadia Derbey7748dbf2007-10-18 23:40:49 -070058};
59
Mike Waychisonae781772005-09-06 15:17:09 -070060struct seq_file;
Pierre Peiffered2ddbf2008-02-08 04:18:57 -080061struct ipc_ids;
Cedric Le Goater7d69a1f2007-07-15 23:40:58 -070062
Nadia Derbey7ca7e562007-10-18 23:40:48 -070063void ipc_init_ids(struct ipc_ids *);
Mike Waychisonae781772005-09-06 15:17:09 -070064#ifdef CONFIG_PROC_FS
65void __init ipc_init_proc_interface(const char *path, const char *header,
Kirill Korotaev73ea4132006-10-02 02:18:20 -070066 int ids, int (*show)(struct seq_file *, void *));
Mike Waychisonae781772005-09-06 15:17:09 -070067#else
68#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
69#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070070
Kirill Korotaev73ea4132006-10-02 02:18:20 -070071#define IPC_SEM_IDS 0
72#define IPC_MSG_IDS 1
73#define IPC_SHM_IDS 2
74
Nadia Derbeyce621f52007-10-18 23:40:52 -070075#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
76
Nadia Derbey3e148c72007-10-18 23:40:54 -070077/* must be called with ids->rw_mutex acquired for writing */
Nadia Derbey7ca7e562007-10-18 23:40:48 -070078int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
Nadia Derbey3e148c72007-10-18 23:40:54 -070079
80/* must be called with ids->rw_mutex acquired for reading */
Nadia Derbey7ca7e562007-10-18 23:40:48 -070081int ipc_get_maxid(struct ipc_ids *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
83/* must be called with both locks acquired. */
Nadia Derbey7ca7e562007-10-18 23:40:48 -070084void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070085
Nadia Derbeyf4566f02007-10-18 23:40:53 -070086/* must be called with ipcp locked */
87int ipcperms(struct kern_ipc_perm *ipcp, short flg);
Linus Torvalds1da177e2005-04-16 15:20:36 -070088
89/* for rare, potentially huge allocations.
90 * both function can sleep
91 */
92void* ipc_alloc(int size);
93void ipc_free(void* ptr, int size);
94
95/*
96 * For allocation that need to be freed by RCU.
97 * Objects are reference counted, they start with reference count 1.
98 * getref increases the refcount, the putref call that reduces the recount
99 * to 0 schedules the rcu destruction. Caller must guarantee locking.
100 */
101void* ipc_rcu_alloc(int size);
102void ipc_rcu_getref(void *ptr);
103void ipc_rcu_putref(void *ptr);
104
Nadia Derbey3e148c72007-10-18 23:40:54 -0700105/*
106 * ipc_lock_down: called with rw_mutex held
107 * ipc_lock: called without that lock held
108 */
109struct kern_ipc_perm *ipc_lock_down(struct ipc_ids *, int);
Nadia Derbey023a5352007-10-18 23:40:51 -0700110struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111
112void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
113void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
Pierre Peiffer8f4a3802008-04-29 01:00:51 -0700114void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700115struct kern_ipc_perm *ipcctl_pre_down(struct ipc_ids *ids, int id, int cmd,
116 struct ipc64_perm *perm, int extra_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117
Chris Zankel813e6782005-07-12 13:58:25 -0700118#if defined(__ia64__) || defined(__x86_64__) || defined(__hppa__) || defined(__XTENSA__)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 /* On IA-64, we always use the "64-bit version" of the IPC structures. */
120# define ipc_parse_version(cmd) IPC_64
121#else
122int ipc_parse_version (int *cmd);
123#endif
124
125extern void free_msg(struct msg_msg *msg);
126extern struct msg_msg *load_msg(const void __user *src, int len);
127extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700128
Nadia Derbeyb6b337a2008-04-29 01:00:42 -0700129extern void recompute_msgmni(struct ipc_namespace *);
130
Nadia Derbey1b531f22007-10-18 23:40:55 -0700131static inline int ipc_buildid(int id, int seq)
Nadia Derbey28028312007-10-18 23:40:52 -0700132{
133 return SEQ_MULTIPLIER * seq + id;
134}
135
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700136/*
137 * Must be called with ipcp locked
138 */
Nadia Derbey1b531f22007-10-18 23:40:55 -0700139static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
Nadia Derbey023a5352007-10-18 23:40:51 -0700140{
141 if (uid / SEQ_MULTIPLIER != ipcp->seq)
142 return 1;
143 return 0;
144}
145
146static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
147{
148 rcu_read_lock();
149 spin_lock(&perm->lock);
150}
151
152static inline void ipc_unlock(struct kern_ipc_perm *perm)
153{
154 spin_unlock(&perm->lock);
155 rcu_read_unlock();
156}
157
Pavel Emelyanovb2d75cd2008-02-08 04:18:54 -0800158struct kern_ipc_perm *ipc_lock_check_down(struct ipc_ids *ids, int id);
159struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id);
160int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
161 struct ipc_ops *ops, struct ipc_params *params);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162
163#endif