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 USHRT_MAX 0xffff
16 #define SEQ_MULTIPLIER (IPCMNI)
17
18 void sem_init (void);
19 void msg_init (void);
20 void shm_init (void);
21
22 struct ipc_namespace;
23
24 void sem_init_ns(struct ipc_namespace *ns);
25 void msg_init_ns(struct ipc_namespace *ns);
26 void shm_init_ns(struct ipc_namespace *ns);
27
28 void sem_exit_ns(struct ipc_namespace *ns);
29 void msg_exit_ns(struct ipc_namespace *ns);
30 void shm_exit_ns(struct ipc_namespace *ns);
31
32 /*
33 * Structure that holds the parameters needed by the ipc operations
34 * (see after)
35 */
36 struct ipc_params {
37 key_t key;
38 int flg;
39 union {
40 size_t size; /* for shared memories */
41 int nsems; /* for semaphores */
42 } u; /* holds the getnew() specific param */
43 };
44
45 /*
46 * Structure that holds some ipc operations. This structure is used to unify
47 * the calls to sys_msgget(), sys_semget(), sys_shmget()
48 * . routine to call to create a new ipc object. Can be one of newque,
49 * newary, newseg
50 * . routine to call to check permissions for a new ipc object.
51 * Can be one of security_msg_associate, security_sem_associate,
52 * security_shm_associate
53 * . routine to call for an extra check if needed
54 */
55 struct ipc_ops {
56 int (*getnew) (struct ipc_namespace *, struct ipc_params *);
57 int (*associate) (struct kern_ipc_perm *, int);
58 int (*more_checks) (struct kern_ipc_perm *, struct ipc_params *);
59 };
60
61 struct seq_file;
62 struct ipc_ids;
63
64 void ipc_init_ids(struct ipc_ids *);
65 #ifdef CONFIG_PROC_FS
66 void __init ipc_init_proc_interface(const char *path, const char *header,
67 int ids, int (*show)(struct seq_file *, void *));
68 #else
69 #define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
70 #endif
71
72 #define IPC_SEM_IDS 0
73 #define IPC_MSG_IDS 1
74 #define IPC_SHM_IDS 2
75
76 #define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
77
78 /* must be called with ids->rw_mutex acquired for writing */
79 int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
80
81 /* must be called with ids->rw_mutex acquired for reading */
82 int ipc_get_maxid(struct ipc_ids *);
83
84 /* must be called with both locks acquired. */
85 void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
86
87 /* must be called with ipcp locked */
88 int ipcperms(struct kern_ipc_perm *ipcp, short flg);
89
90 /* for rare, potentially huge allocations.
91 * both function can sleep
92 */
93 void* ipc_alloc(int size);
94 void ipc_free(void* ptr, int size);
95
96 /*
97 * For allocation that need to be freed by RCU.
98 * Objects are reference counted, they start with reference count 1.
99 * getref increases the refcount, the putref call that reduces the recount
100 * to 0 schedules the rcu destruction. Caller must guarantee locking.
101 */
102 void* ipc_rcu_alloc(int size);
103 void ipc_rcu_getref(void *ptr);
104 void ipc_rcu_putref(void *ptr);
105
106 /*
107 * ipc_lock_down: called with rw_mutex held
108 * ipc_lock: called without that lock held
109 */
110 struct kern_ipc_perm *ipc_lock_down(struct ipc_ids *, int);
111 struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
112
113 void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
114 void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
115
116 #if defined(__ia64__) || defined(__x86_64__) || defined(__hppa__) || defined(__XTENSA__)
117 /* On IA-64, we always use the "64-bit version" of the IPC structures. */
118 # define ipc_parse_version(cmd) IPC_64
119 #else
120 int ipc_parse_version (int *cmd);
121 #endif
122
123 extern void free_msg(struct msg_msg *msg);
124 extern struct msg_msg *load_msg(const void __user *src, int len);
125 extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
126
127 static inline int ipc_buildid(int id, int seq)
128 {
129 return SEQ_MULTIPLIER * seq + id;
130 }
131
132 /*
133 * Must be called with ipcp locked
134 */
135 static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
136 {
137 if (uid / SEQ_MULTIPLIER != ipcp->seq)
138 return 1;
139 return 0;
140 }
141
142 static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
143 {
144 rcu_read_lock();
145 spin_lock(&perm->lock);
146 }
147
148 static inline void ipc_unlock(struct kern_ipc_perm *perm)
149 {
150 spin_unlock(&perm->lock);
151 rcu_read_unlock();
152 }
153
154 struct kern_ipc_perm *ipc_lock_check_down(struct ipc_ids *ids, int id);
155 struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id);
156 int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
157 struct ipc_ops *ops, struct ipc_params *params);
158
159 #endif
160
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