util.h revision 6062a8dc
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
50/*
51 * Structure that holds the parameters needed by the ipc operations
52 * (see after)
53 */
54struct ipc_params {
55	key_t key;
56	int flg;
57	union {
58		size_t size;	/* for shared memories */
59		int nsems;	/* for semaphores */
60	} u;			/* holds the getnew() specific param */
61};
62
63/*
64 * Structure that holds some ipc operations. This structure is used to unify
65 * the calls to sys_msgget(), sys_semget(), sys_shmget()
66 *      . routine to call to create a new ipc object. Can be one of newque,
67 *        newary, newseg
68 *      . routine to call to check permissions for a new ipc object.
69 *        Can be one of security_msg_associate, security_sem_associate,
70 *        security_shm_associate
71 *      . routine to call for an extra check if needed
72 */
73struct ipc_ops {
74	int (*getnew) (struct ipc_namespace *, struct ipc_params *);
75	int (*associate) (struct kern_ipc_perm *, int);
76	int (*more_checks) (struct kern_ipc_perm *, struct ipc_params *);
77};
78
79struct seq_file;
80struct ipc_ids;
81
82void ipc_init_ids(struct ipc_ids *);
83#ifdef CONFIG_PROC_FS
84void __init ipc_init_proc_interface(const char *path, const char *header,
85		int ids, int (*show)(struct seq_file *, void *));
86#else
87#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
88#endif
89
90#define IPC_SEM_IDS	0
91#define IPC_MSG_IDS	1
92#define IPC_SHM_IDS	2
93
94#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
95#define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER)
96
97/* must be called with ids->rw_mutex acquired for writing */
98int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
99
100/* must be called with ids->rw_mutex acquired for reading */
101int ipc_get_maxid(struct ipc_ids *);
102
103/* must be called with both locks acquired. */
104void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
105
106/* must be called with ipcp locked */
107int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
108
109/* for rare, potentially huge allocations.
110 * both function can sleep
111 */
112void* ipc_alloc(int size);
113void ipc_free(void* ptr, int size);
114
115/*
116 * For allocation that need to be freed by RCU.
117 * Objects are reference counted, they start with reference count 1.
118 * getref increases the refcount, the putref call that reduces the recount
119 * to 0 schedules the rcu destruction. Caller must guarantee locking.
120 */
121void* ipc_rcu_alloc(int size);
122int ipc_rcu_getref(void *ptr);
123void ipc_rcu_putref(void *ptr);
124
125struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
126struct kern_ipc_perm *ipc_obtain_object(struct ipc_ids *ids, int id);
127
128void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
129void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
130int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
131struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns,
132					     struct ipc_ids *ids, int id, int cmd,
133					     struct ipc64_perm *perm, int extra_perm);
134struct kern_ipc_perm *ipcctl_pre_down(struct ipc_namespace *ns,
135				      struct ipc_ids *ids, int id, int cmd,
136				      struct ipc64_perm *perm, int extra_perm);
137
138#ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
139  /* On IA-64, we always use the "64-bit version" of the IPC structures.  */
140# define ipc_parse_version(cmd)	IPC_64
141#else
142int ipc_parse_version (int *cmd);
143#endif
144
145extern void free_msg(struct msg_msg *msg);
146extern struct msg_msg *load_msg(const void __user *src, int len);
147extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
148extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
149
150extern void recompute_msgmni(struct ipc_namespace *);
151
152static inline int ipc_buildid(int id, int seq)
153{
154	return SEQ_MULTIPLIER * seq + id;
155}
156
157static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
158{
159	return uid / SEQ_MULTIPLIER != ipcp->seq;
160}
161
162static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
163{
164	rcu_read_lock();
165	spin_lock(&perm->lock);
166}
167
168static inline void ipc_unlock(struct kern_ipc_perm *perm)
169{
170	spin_unlock(&perm->lock);
171	rcu_read_unlock();
172}
173
174static inline void ipc_lock_object(struct kern_ipc_perm *perm)
175{
176	spin_lock(&perm->lock);
177}
178
179struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id);
180struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
181int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
182			struct ipc_ops *ops, struct ipc_params *params);
183void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
184		void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
185#endif
186