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
17 void sem_init (void);
18 void msg_init (void);
19 void shm_init (void);
20
21 struct ipc_namespace;
22
23 void sem_init_ns(struct ipc_namespace *ns);
24 void msg_init_ns(struct ipc_namespace *ns);
25 void shm_init_ns(struct ipc_namespace *ns);
26
27 void sem_exit_ns(struct ipc_namespace *ns);
28 void msg_exit_ns(struct ipc_namespace *ns);
29 void shm_exit_ns(struct ipc_namespace *ns);
30
31 /*
32 * Structure that holds the parameters needed by the ipc operations
33 * (see after)
34 */
35 struct 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 */
54 struct 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
60 struct seq_file;
61 struct ipc_ids;
62
63 void ipc_init_ids(struct ipc_ids *);
64 #ifdef CONFIG_PROC_FS
65 void __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 */
78 int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
79
80 /* must be called with ids->rw_mutex acquired for reading */
81 int ipc_get_maxid(struct ipc_ids *);
82
83 /* must be called with both locks acquired. */
84 void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
85
86 /* must be called with ipcp locked */
87 int ipcperms(struct kern_ipc_perm *ipcp, short flg);
88
89 /* for rare, potentially huge allocations.
90 * both function can sleep
91 */
92 void* ipc_alloc(int size);
93 void 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 */
101 void* ipc_rcu_alloc(int size);
102 void ipc_rcu_getref(void *ptr);
103 void ipc_rcu_putref(void *ptr);
104
105 struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
106
107 void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
108 void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
109 void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
110 struct 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
117 int ipc_parse_version (int *cmd);
118 #endif
119
120 extern void free_msg(struct msg_msg *msg);
121 extern struct msg_msg *load_msg(const void __user *src, int len);
122 extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
123
124 extern void recompute_msgmni(struct ipc_namespace *);
125
ipc_buildid(int id,int seq)126 static 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 */
ipc_checkid(struct kern_ipc_perm * ipcp,int uid)134 static 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
ipc_lock_by_ptr(struct kern_ipc_perm * perm)141 static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
142 {
143 rcu_read_lock();
144 spin_lock(&perm->lock);
145 }
146
ipc_unlock(struct kern_ipc_perm * perm)147 static inline void ipc_unlock(struct kern_ipc_perm *perm)
148 {
149 spin_unlock(&perm->lock);
150 rcu_read_unlock();
151 }
152
153 struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id);
154 int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
155 struct ipc_ops *ops, struct ipc_params *params);
156
157 #endif
158