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1da177e4 LT |
1 | /* |
2 | * linux/ipc/util.h | |
3 | * Copyright (C) 1999 Christoph Rohland | |
4 | * | |
624dffcb | 5 | * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com> |
73ea4130 KK |
6 | * namespaces support. 2006 OpenVZ, SWsoft Inc. |
7 | * Pavel Emelianov <xemul@openvz.org> | |
1da177e4 LT |
8 | */ |
9 | ||
10 | #ifndef _IPC_UTIL_H | |
11 | #define _IPC_UTIL_H | |
12 | ||
7ca7e564 | 13 | #include <linux/idr.h> |
023a5355 | 14 | #include <linux/err.h> |
7ca7e564 | 15 | |
1da177e4 LT |
16 | #define USHRT_MAX 0xffff |
17 | #define SEQ_MULTIPLIER (IPCMNI) | |
18 | ||
19 | void sem_init (void); | |
20 | void msg_init (void); | |
21 | void shm_init (void); | |
22 | ||
73ea4130 KK |
23 | int sem_init_ns(struct ipc_namespace *ns); |
24 | int msg_init_ns(struct ipc_namespace *ns); | |
25 | int 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 | ||
1da177e4 LT |
31 | struct ipc_ids { |
32 | int in_use; | |
1da177e4 LT |
33 | unsigned short seq; |
34 | unsigned short seq_max; | |
5f921ae9 | 35 | struct mutex mutex; |
7ca7e564 | 36 | struct idr ipcs_idr; |
1da177e4 LT |
37 | }; |
38 | ||
7748dbfa ND |
39 | /* |
40 | * Structure that holds the parameters needed by the ipc operations | |
41 | * (see after) | |
42 | */ | |
43 | struct ipc_params { | |
44 | key_t key; | |
45 | int flg; | |
46 | union { | |
47 | size_t size; /* for shared memories */ | |
48 | int nsems; /* for semaphores */ | |
49 | } u; /* holds the getnew() specific param */ | |
50 | }; | |
51 | ||
52 | /* | |
53 | * Structure that holds some ipc operations. This structure is used to unify | |
54 | * the calls to sys_msgget(), sys_semget(), sys_shmget() | |
55 | * . routine to call to create a new ipc object. Can be one of newque, | |
56 | * newary, newseg | |
57 | * . routine to call to call to check permissions for a new ipc object. | |
58 | * Can be one of security_msg_associate, security_sem_associate, | |
59 | * security_shm_associate | |
60 | * . routine to call for an extra check if needed | |
61 | */ | |
62 | struct ipc_ops { | |
63 | int (*getnew) (struct ipc_namespace *, struct ipc_params *); | |
64 | int (*associate) (void *, int); | |
65 | int (*more_checks) (void *, struct ipc_params *); | |
66 | }; | |
67 | ||
ae781774 | 68 | struct seq_file; |
7d69a1f4 | 69 | |
7ca7e564 | 70 | void ipc_init_ids(struct ipc_ids *); |
ae781774 MW |
71 | #ifdef CONFIG_PROC_FS |
72 | void __init ipc_init_proc_interface(const char *path, const char *header, | |
73ea4130 | 73 | int ids, int (*show)(struct seq_file *, void *)); |
ae781774 MW |
74 | #else |
75 | #define ipc_init_proc_interface(path, header, ids, show) do {} while (0) | |
76 | #endif | |
1da177e4 | 77 | |
73ea4130 KK |
78 | #define IPC_SEM_IDS 0 |
79 | #define IPC_MSG_IDS 1 | |
80 | #define IPC_SHM_IDS 2 | |
81 | ||
5f921ae9 | 82 | /* must be called with ids->mutex acquired.*/ |
7ca7e564 ND |
83 | int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int); |
84 | int ipc_get_maxid(struct ipc_ids *); | |
1da177e4 LT |
85 | |
86 | /* must be called with both locks acquired. */ | |
7ca7e564 | 87 | void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *); |
1da177e4 LT |
88 | |
89 | int ipcperms (struct kern_ipc_perm *ipcp, short flg); | |
90 | ||
91 | /* for rare, potentially huge allocations. | |
92 | * both function can sleep | |
93 | */ | |
94 | void* ipc_alloc(int size); | |
95 | void ipc_free(void* ptr, int size); | |
96 | ||
97 | /* | |
98 | * For allocation that need to be freed by RCU. | |
99 | * Objects are reference counted, they start with reference count 1. | |
100 | * getref increases the refcount, the putref call that reduces the recount | |
101 | * to 0 schedules the rcu destruction. Caller must guarantee locking. | |
102 | */ | |
103 | void* ipc_rcu_alloc(int size); | |
104 | void ipc_rcu_getref(void *ptr); | |
105 | void ipc_rcu_putref(void *ptr); | |
106 | ||
023a5355 | 107 | struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int); |
1da177e4 | 108 | int ipc_buildid(struct ipc_ids* ids, int id, int seq); |
1da177e4 LT |
109 | |
110 | void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out); | |
111 | void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out); | |
112 | ||
813e6783 | 113 | #if defined(__ia64__) || defined(__x86_64__) || defined(__hppa__) || defined(__XTENSA__) |
1da177e4 LT |
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); | |
7748dbfa ND |
123 | extern int ipcget_new(struct ipc_namespace *, struct ipc_ids *, |
124 | struct ipc_ops *, struct ipc_params *); | |
125 | extern int ipcget_public(struct ipc_namespace *, struct ipc_ids *, | |
126 | struct ipc_ops *, struct ipc_params *); | |
127 | ||
023a5355 ND |
128 | static inline int ipc_checkid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp, |
129 | int uid) | |
130 | { | |
131 | if (uid / SEQ_MULTIPLIER != ipcp->seq) | |
132 | return 1; | |
133 | return 0; | |
134 | } | |
135 | ||
136 | static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm) | |
137 | { | |
138 | rcu_read_lock(); | |
139 | spin_lock(&perm->lock); | |
140 | } | |
141 | ||
142 | static inline void ipc_unlock(struct kern_ipc_perm *perm) | |
143 | { | |
144 | spin_unlock(&perm->lock); | |
145 | rcu_read_unlock(); | |
146 | } | |
147 | ||
148 | static inline struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, | |
149 | int id) | |
150 | { | |
151 | struct kern_ipc_perm *out; | |
152 | ||
153 | out = ipc_lock(ids, id); | |
154 | if (IS_ERR(out)) | |
155 | return out; | |
156 | ||
157 | if (ipc_checkid(ids, out, id)) { | |
158 | ipc_unlock(out); | |
159 | return ERR_PTR(-EIDRM); | |
160 | } | |
161 | ||
162 | return out; | |
163 | } | |
164 | ||
7748dbfa ND |
165 | static inline int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, |
166 | struct ipc_ops *ops, struct ipc_params *params) | |
167 | { | |
168 | if (params->key == IPC_PRIVATE) | |
169 | return ipcget_new(ns, ids, ops, params); | |
170 | else | |
171 | return ipcget_public(ns, ids, ops, params); | |
172 | } | |
1da177e4 LT |
173 | |
174 | #endif |