1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
|
/*
* linux/ipc/util.h
* Copyright (C) 1999 Christoph Rohland
*
* ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com>
* namespaces support. 2006 OpenVZ, SWsoft Inc.
* Pavel Emelianov <xemul@openvz.org>
*/
#ifndef _IPC_UTIL_H
#define _IPC_UTIL_H
#include <linux/idr.h>
#include <linux/err.h>
#define USHRT_MAX 0xffff
#define SEQ_MULTIPLIER (IPCMNI)
void sem_init (void);
void msg_init (void);
void shm_init (void);
struct ipc_namespace;
int sem_init_ns(struct ipc_namespace *ns);
int msg_init_ns(struct ipc_namespace *ns);
int shm_init_ns(struct ipc_namespace *ns);
void sem_exit_ns(struct ipc_namespace *ns);
void msg_exit_ns(struct ipc_namespace *ns);
void shm_exit_ns(struct ipc_namespace *ns);
struct ipc_ids {
int in_use;
unsigned short seq;
unsigned short seq_max;
struct rw_semaphore rw_mutex;
struct idr ipcs_idr;
};
/*
* Structure that holds the parameters needed by the ipc operations
* (see after)
*/
struct ipc_params {
key_t key;
int flg;
union {
size_t size; /* for shared memories */
int nsems; /* for semaphores */
} u; /* holds the getnew() specific param */
};
/*
* Structure that holds some ipc operations. This structure is used to unify
* the calls to sys_msgget(), sys_semget(), sys_shmget()
* . routine to call to create a new ipc object. Can be one of newque,
* newary, newseg
* . routine to call to check permissions for a new ipc object.
* Can be one of security_msg_associate, security_sem_associate,
* security_shm_associate
* . routine to call for an extra check if needed
*/
struct ipc_ops {
int (*getnew) (struct ipc_namespace *, struct ipc_params *);
int (*associate) (struct kern_ipc_perm *, int);
int (*more_checks) (struct kern_ipc_perm *, struct ipc_params *);
};
struct seq_file;
void ipc_init_ids(struct ipc_ids *);
#ifdef CONFIG_PROC_FS
void __init ipc_init_proc_interface(const char *path, const char *header,
int ids, int (*show)(struct seq_file *, void *));
#else
#define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
#endif
#define IPC_SEM_IDS 0
#define IPC_MSG_IDS 1
#define IPC_SHM_IDS 2
#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
/* must be called with ids->rw_mutex acquired for writing */
int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
/* must be called with ids->rw_mutex acquired for reading */
int ipc_get_maxid(struct ipc_ids *);
/* must be called with both locks acquired. */
void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
/* must be called with ipcp locked */
int ipcperms(struct kern_ipc_perm *ipcp, short flg);
/* for rare, potentially huge allocations.
* both function can sleep
*/
void* ipc_alloc(int size);
void ipc_free(void* ptr, int size);
/*
* For allocation that need to be freed by RCU.
* Objects are reference counted, they start with reference count 1.
* getref increases the refcount, the putref call that reduces the recount
* to 0 schedules the rcu destruction. Caller must guarantee locking.
*/
void* ipc_rcu_alloc(int size);
void ipc_rcu_getref(void *ptr);
void ipc_rcu_putref(void *ptr);
/*
* ipc_lock_down: called with rw_mutex held
* ipc_lock: called without that lock held
*/
struct kern_ipc_perm *ipc_lock_down(struct ipc_ids *, int);
struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
#if defined(__ia64__) || defined(__x86_64__) || defined(__hppa__) || defined(__XTENSA__)
/* On IA-64, we always use the "64-bit version" of the IPC structures. */
# define ipc_parse_version(cmd) IPC_64
#else
int ipc_parse_version (int *cmd);
#endif
extern void free_msg(struct msg_msg *msg);
extern struct msg_msg *load_msg(const void __user *src, int len);
extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
extern int ipcget_new(struct ipc_namespace *, struct ipc_ids *,
struct ipc_ops *, struct ipc_params *);
extern int ipcget_public(struct ipc_namespace *, struct ipc_ids *,
struct ipc_ops *, struct ipc_params *);
static inline int ipc_buildid(int id, int seq)
{
return SEQ_MULTIPLIER * seq + id;
}
/*
* Must be called with ipcp locked
*/
static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
{
if (uid / SEQ_MULTIPLIER != ipcp->seq)
return 1;
return 0;
}
static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
{
rcu_read_lock();
spin_lock(&perm->lock);
}
static inline void ipc_unlock(struct kern_ipc_perm *perm)
{
spin_unlock(&perm->lock);
rcu_read_unlock();
}
static inline struct kern_ipc_perm *ipc_lock_check_down(struct ipc_ids *ids,
int id)
{
struct kern_ipc_perm *out;
out = ipc_lock_down(ids, id);
if (IS_ERR(out))
return out;
if (ipc_checkid(out, id)) {
ipc_unlock(out);
return ERR_PTR(-EIDRM);
}
return out;
}
static inline struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids,
int id)
{
struct kern_ipc_perm *out;
out = ipc_lock(ids, id);
if (IS_ERR(out))
return out;
if (ipc_checkid(out, id)) {
ipc_unlock(out);
return ERR_PTR(-EIDRM);
}
return out;
}
/**
* ipcget - Common sys_*get() code
* @ns : namsepace
* @ids : IPC identifier set
* @ops : operations to be called on ipc object creation, permission checks
* and further checks
* @params : the parameters needed by the previous operations.
*
* Common routine called by sys_msgget(), sys_semget() and sys_shmget().
*/
static inline int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
struct ipc_ops *ops, struct ipc_params *params)
{
if (params->key == IPC_PRIVATE)
return ipcget_new(ns, ids, ops, params);
else
return ipcget_public(ns, ids, ops, params);
}
#endif
|
