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
18 void sem_init (void);
19 void msg_init (void);
20 void shm_init (void);
21
22 struct ipc_namespace;
23
24 #ifdef CONFIG_POSIX_MQUEUE
25 extern void mq_clear_sbinfo(struct ipc_namespace *ns);
26 extern void mq_put_mnt(struct ipc_namespace *ns);
27 #else
mq_clear_sbinfo(struct ipc_namespace * ns)28 static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
mq_put_mnt(struct ipc_namespace * ns)29 static inline void mq_put_mnt(struct ipc_namespace *ns) { }
30 #endif
31
32 #ifdef CONFIG_SYSVIPC
33 void sem_init_ns(struct ipc_namespace *ns);
34 void msg_init_ns(struct ipc_namespace *ns);
35 void shm_init_ns(struct ipc_namespace *ns);
36
37 void sem_exit_ns(struct ipc_namespace *ns);
38 void msg_exit_ns(struct ipc_namespace *ns);
39 void shm_exit_ns(struct ipc_namespace *ns);
40 #else
sem_init_ns(struct ipc_namespace * ns)41 static inline void sem_init_ns(struct ipc_namespace *ns) { }
msg_init_ns(struct ipc_namespace * ns)42 static inline void msg_init_ns(struct ipc_namespace *ns) { }
shm_init_ns(struct ipc_namespace * ns)43 static inline void shm_init_ns(struct ipc_namespace *ns) { }
44
sem_exit_ns(struct ipc_namespace * ns)45 static inline void sem_exit_ns(struct ipc_namespace *ns) { }
msg_exit_ns(struct ipc_namespace * ns)46 static inline void msg_exit_ns(struct ipc_namespace *ns) { }
shm_exit_ns(struct ipc_namespace * ns)47 static 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 */
54 struct 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 */
73 struct 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
79 struct seq_file;
80 struct ipc_ids;
81
82 void ipc_init_ids(struct ipc_ids *);
83 #ifdef CONFIG_PROC_FS
84 void __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 */
97 int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
98
99 /* must be called with ids->rw_mutex acquired for reading */
100 int ipc_get_maxid(struct ipc_ids *);
101
102 /* must be called with both locks acquired. */
103 void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
104
105 /* must be called with ipcp locked */
106 int 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 */
111 void* ipc_alloc(int size);
112 void 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 */
120 void* ipc_rcu_alloc(int size);
121 void ipc_rcu_getref(void *ptr);
122 void ipc_rcu_putref(void *ptr);
123
124 struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
125
126 void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
127 void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
128 void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
129 struct 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
137 int ipc_parse_version (int *cmd);
138 #endif
139
140 extern void free_msg(struct msg_msg *msg);
141 extern struct msg_msg *load_msg(const void __user *src, int len);
142 extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
143
144 extern void recompute_msgmni(struct ipc_namespace *);
145
ipc_buildid(int id,int seq)146 static 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 */
ipc_checkid(struct kern_ipc_perm * ipcp,int uid)154 static 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
ipc_lock_by_ptr(struct kern_ipc_perm * perm)161 static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
162 {
163 rcu_read_lock();
164 spin_lock(&perm->lock);
165 }
166
ipc_unlock(struct kern_ipc_perm * perm)167 static inline void ipc_unlock(struct kern_ipc_perm *perm)
168 {
169 spin_unlock(&perm->lock);
170 rcu_read_unlock();
171 }
172
173 struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id);
174 int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
175 struct ipc_ops *ops, struct ipc_params *params);
176 void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
177 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
178 #endif
179