Root/ipc/util.h

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
96/* must be called with ids->rw_mutex acquired for writing */
97int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
98
99/* must be called with ids->rw_mutex acquired for reading */
100int ipc_get_maxid(struct ipc_ids *);
101
102/* must be called with both locks acquired. */
103void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
104
105/* must be called with ipcp locked */
106int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
107
108/* for rare, potentially huge allocations.
109 * both function can sleep
110 */
111void* ipc_alloc(int size);
112void ipc_free(void* ptr, int size);
113
114/*
115 * For allocation that need to be freed by RCU.
116 * Objects are reference counted, they start with reference count 1.
117 * getref increases the refcount, the putref call that reduces the recount
118 * to 0 schedules the rcu destruction. Caller must guarantee locking.
119 */
120void* ipc_rcu_alloc(int size);
121void ipc_rcu_getref(void *ptr);
122void ipc_rcu_putref(void *ptr);
123
124struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
125
126void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
127void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
128void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
129struct kern_ipc_perm *ipcctl_pre_down(struct ipc_namespace *ns,
130                      struct ipc_ids *ids, int id, int cmd,
131                      struct ipc64_perm *perm, int extra_perm);
132
133#ifndef __ARCH_WANT_IPC_PARSE_VERSION
134  /* On IA-64, we always use the "64-bit version" of the IPC structures. */
135# define ipc_parse_version(cmd) IPC_64
136#else
137int ipc_parse_version (int *cmd);
138#endif
139
140extern void free_msg(struct msg_msg *msg);
141extern struct msg_msg *load_msg(const void __user *src, int len);
142extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
143
144extern void recompute_msgmni(struct ipc_namespace *);
145
146static inline int ipc_buildid(int id, int seq)
147{
148    return SEQ_MULTIPLIER * seq + id;
149}
150
151/*
152 * Must be called with ipcp locked
153 */
154static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
155{
156    if (uid / SEQ_MULTIPLIER != ipcp->seq)
157        return 1;
158    return 0;
159}
160
161static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
162{
163    rcu_read_lock();
164    spin_lock(&perm->lock);
165}
166
167static inline void ipc_unlock(struct kern_ipc_perm *perm)
168{
169    spin_unlock(&perm->lock);
170    rcu_read_unlock();
171}
172
173struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id);
174int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
175            struct ipc_ops *ops, struct ipc_params *params);
176void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
177        void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
178#endif
179

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