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Linux kernel mirror (for testing)
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kernel
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linux
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/err.h>
14
15#define SEQ_MULTIPLIER (IPCMNI)
16
17void sem_init (void);
18void msg_init (void);
19void shm_init (void);
20
21struct ipc_namespace;
22
23void sem_init_ns(struct ipc_namespace *ns);
24void msg_init_ns(struct ipc_namespace *ns);
25void shm_init_ns(struct ipc_namespace *ns);
26
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
31/*
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
49 * . routine to call to check permissions for a new ipc object.
50 * 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 *);
56 int (*associate) (struct kern_ipc_perm *, int);
57 int (*more_checks) (struct kern_ipc_perm *, struct ipc_params *);
58};
59
60struct seq_file;
61struct ipc_ids;
62
63void ipc_init_ids(struct ipc_ids *);
64#ifdef CONFIG_PROC_FS
65void __init ipc_init_proc_interface(const char *path, const char *header,
66 int ids, int (*show)(struct seq_file *, void *));
67#else
68#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
69#endif
70
71#define IPC_SEM_IDS 0
72#define IPC_MSG_IDS 1
73#define IPC_SHM_IDS 2
74
75#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
76
77/* must be called with ids->rw_mutex acquired for writing */
78int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
79
80/* must be called with ids->rw_mutex acquired for reading */
81int ipc_get_maxid(struct ipc_ids *);
82
83/* must be called with both locks acquired. */
84void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
85
86/* must be called with ipcp locked */
87int ipcperms(struct kern_ipc_perm *ipcp, short flg);
88
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
105struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
106
107void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
108void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
109void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
110struct kern_ipc_perm *ipcctl_pre_down(struct ipc_ids *ids, int id, int cmd,
111 struct ipc64_perm *perm, int extra_perm);
112
113#if defined(__ia64__) || defined(__x86_64__) || defined(__hppa__) || defined(__XTENSA__)
114 /* On IA-64, we always use the "64-bit version" of the IPC structures. */
115# define ipc_parse_version(cmd) IPC_64
116#else
117int ipc_parse_version (int *cmd);
118#endif
119
120extern void free_msg(struct msg_msg *msg);
121extern struct msg_msg *load_msg(const void __user *src, int len);
122extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
123
124extern void recompute_msgmni(struct ipc_namespace *);
125
126static inline int ipc_buildid(int id, int seq)
127{
128 return SEQ_MULTIPLIER * seq + id;
129}
130
131/*
132 * Must be called with ipcp locked
133 */
134static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
135{
136 if (uid / SEQ_MULTIPLIER != ipcp->seq)
137 return 1;
138 return 0;
139}
140
141static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
142{
143 rcu_read_lock();
144 spin_lock(&perm->lock);
145}
146
147static inline void ipc_unlock(struct kern_ipc_perm *perm)
148{
149 spin_unlock(&perm->lock);
150 rcu_read_unlock();
151}
152
153struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id);
154int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
155 struct ipc_ops *ops, struct ipc_params *params);
156
157#endif