summaryrefslogtreecommitdiff
path: root/ipc/util.h
blob: 0cd6201fe63a4a0cb73e841fdf910c38467ec52d (plain)
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
220
221
222
223
/* SPDX-License-Identifier: GPL-2.0 */
/*
 * 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/unistd.h>
#include <linux/err.h>

#define SEQ_MULTIPLIER	(IPCMNI)

int sem_init(void);
int msg_init(void);
void shm_init(void);

struct ipc_namespace;

#ifdef CONFIG_POSIX_MQUEUE
extern void mq_clear_sbinfo(struct ipc_namespace *ns);
extern void mq_put_mnt(struct ipc_namespace *ns);
#else
static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { }
static inline void mq_put_mnt(struct ipc_namespace *ns) { }
#endif

#ifdef CONFIG_SYSVIPC
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);
#else
static inline int sem_init_ns(struct ipc_namespace *ns) { return 0; }
static inline int msg_init_ns(struct ipc_namespace *ns) { return 0; }
static inline int shm_init_ns(struct ipc_namespace *ns) { return 0; }

static inline void sem_exit_ns(struct ipc_namespace *ns) { }
static inline void msg_exit_ns(struct ipc_namespace *ns) { }
static inline void shm_exit_ns(struct ipc_namespace *ns) { }
#endif

/*
 * 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;
struct ipc_ids;

int 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)
#define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER)
#define IPCID_SEQ_MAX min_t(int, INT_MAX/SEQ_MULTIPLIER, USHRT_MAX)

/* must be called with ids->rwsem acquired for writing */
int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);

/* must be called with ids->rwsem 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 both locks acquired. */
void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *);

/* must be called with ipcp locked */
int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);

/*
 * 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.
 *
 * refcount is initialized by ipc_addid(), before that point call_rcu()
 * must be used.
 */
int ipc_rcu_getref(struct kern_ipc_perm *ptr);
void ipc_rcu_putref(struct kern_ipc_perm *ptr,
			void (*func)(struct rcu_head *head));

struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);

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);
int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns,
					     struct ipc_ids *ids, int id, int cmd,
					     struct ipc64_perm *perm, int extra_perm);

#ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
/* 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, size_t len);
extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);

static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
{
	return uid / SEQ_MULTIPLIER != ipcp->seq;
}

static inline void ipc_lock_object(struct kern_ipc_perm *perm)
{
	spin_lock(&perm->lock);
}

static inline void ipc_unlock_object(struct kern_ipc_perm *perm)
{
	spin_unlock(&perm->lock);
}

static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm)
{
	assert_spin_locked(&perm->lock);
}

static inline void ipc_unlock(struct kern_ipc_perm *perm)
{
	ipc_unlock_object(perm);
	rcu_read_unlock();
}

/*
 * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths
 * where the respective ipc_ids.rwsem is not being held down.
 * Checks whether the ipc object is still around or if it's gone already, as
 * ipc_rmid() may have already freed the ID while the ipc lock was spinning.
 * Needs to be called with kern_ipc_perm.lock held -- exception made for one
 * checkpoint case at sys_semtimedop() as noted in code commentary.
 */
static inline bool ipc_valid_object(struct kern_ipc_perm *perm)
{
	return !perm->deleted;
}

struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
			const struct ipc_ops *ops, struct ipc_params *params);
void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
		void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));

#ifdef CONFIG_COMPAT
#include <linux/compat.h>
struct compat_ipc_perm {
	key_t key;
	__compat_uid_t uid;
	__compat_gid_t gid;
	__compat_uid_t cuid;
	__compat_gid_t cgid;
	compat_mode_t mode;
	unsigned short seq;
};

void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *);
void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *);
int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *);
int get_compat_ipc64_perm(struct ipc64_perm *,
			  struct compat_ipc64_perm __user *);

static inline int compat_ipc_parse_version(int *cmd)
{
#ifdef	CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
	int version = *cmd & IPC_64;
	*cmd &= ~IPC_64;
	return version;
#else
	return IPC_64;
#endif
}
#endif
#endif