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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | /* |
3 | * linux/ipc/util.h | |
4 | * Copyright (C) 1999 Christoph Rohland | |
5 | * | |
624dffcb | 6 | * ipc helper functions (c) 1999 Manfred Spraul <manfred@colorfullife.com> |
73ea4130 KK |
7 | * namespaces support. 2006 OpenVZ, SWsoft Inc. |
8 | * Pavel Emelianov <xemul@openvz.org> | |
1da177e4 LT |
9 | */ |
10 | ||
11 | #ifndef _IPC_UTIL_H | |
12 | #define _IPC_UTIL_H | |
13 | ||
232086b1 | 14 | #include <linux/unistd.h> |
023a5355 | 15 | #include <linux/err.h> |
15df03c8 | 16 | #include <linux/ipc_namespace.h> |
7ca7e564 | 17 | |
f83a396d | 18 | #define IPCMNI 32768 /* <= MAX_INT limit for ipc arrays (including sysctl changes) */ |
1da177e4 LT |
19 | #define SEQ_MULTIPLIER (IPCMNI) |
20 | ||
0cfb6aee GK |
21 | int sem_init(void); |
22 | int msg_init(void); | |
239521f3 | 23 | void shm_init(void); |
1da177e4 | 24 | |
ae5e1b22 PE |
25 | struct ipc_namespace; |
26 | ||
614b84cf | 27 | #ifdef CONFIG_POSIX_MQUEUE |
7eafd7c7 SH |
28 | extern void mq_clear_sbinfo(struct ipc_namespace *ns); |
29 | extern void mq_put_mnt(struct ipc_namespace *ns); | |
614b84cf | 30 | #else |
7eafd7c7 SH |
31 | static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { } |
32 | static inline void mq_put_mnt(struct ipc_namespace *ns) { } | |
614b84cf SH |
33 | #endif |
34 | ||
35 | #ifdef CONFIG_SYSVIPC | |
0cfb6aee GK |
36 | int sem_init_ns(struct ipc_namespace *ns); |
37 | int msg_init_ns(struct ipc_namespace *ns); | |
38 | int shm_init_ns(struct ipc_namespace *ns); | |
73ea4130 KK |
39 | |
40 | void sem_exit_ns(struct ipc_namespace *ns); | |
41 | void msg_exit_ns(struct ipc_namespace *ns); | |
42 | void shm_exit_ns(struct ipc_namespace *ns); | |
614b84cf | 43 | #else |
0cfb6aee GK |
44 | static inline int sem_init_ns(struct ipc_namespace *ns) { return 0; } |
45 | static inline int msg_init_ns(struct ipc_namespace *ns) { return 0; } | |
46 | static inline int shm_init_ns(struct ipc_namespace *ns) { return 0; } | |
614b84cf SH |
47 | |
48 | static inline void sem_exit_ns(struct ipc_namespace *ns) { } | |
49 | static inline void msg_exit_ns(struct ipc_namespace *ns) { } | |
50 | static inline void shm_exit_ns(struct ipc_namespace *ns) { } | |
51 | #endif | |
73ea4130 | 52 | |
7748dbfa ND |
53 | /* |
54 | * Structure that holds the parameters needed by the ipc operations | |
55 | * (see after) | |
56 | */ | |
57 | struct ipc_params { | |
58 | key_t key; | |
59 | int flg; | |
60 | union { | |
61 | size_t size; /* for shared memories */ | |
62 | int nsems; /* for semaphores */ | |
63 | } u; /* holds the getnew() specific param */ | |
64 | }; | |
65 | ||
66 | /* | |
67 | * Structure that holds some ipc operations. This structure is used to unify | |
68 | * the calls to sys_msgget(), sys_semget(), sys_shmget() | |
69 | * . routine to call to create a new ipc object. Can be one of newque, | |
70 | * newary, newseg | |
f4566f04 | 71 | * . routine to call to check permissions for a new ipc object. |
7748dbfa ND |
72 | * Can be one of security_msg_associate, security_sem_associate, |
73 | * security_shm_associate | |
74 | * . routine to call for an extra check if needed | |
75 | */ | |
76 | struct ipc_ops { | |
46c0a8ca PM |
77 | int (*getnew)(struct ipc_namespace *, struct ipc_params *); |
78 | int (*associate)(struct kern_ipc_perm *, int); | |
79 | int (*more_checks)(struct kern_ipc_perm *, struct ipc_params *); | |
7748dbfa ND |
80 | }; |
81 | ||
ae781774 | 82 | struct seq_file; |
ed2ddbf8 | 83 | struct ipc_ids; |
7d69a1f4 | 84 | |
0cfb6aee | 85 | int ipc_init_ids(struct ipc_ids *); |
ae781774 MW |
86 | #ifdef CONFIG_PROC_FS |
87 | void __init ipc_init_proc_interface(const char *path, const char *header, | |
73ea4130 | 88 | int ids, int (*show)(struct seq_file *, void *)); |
ae781774 MW |
89 | #else |
90 | #define ipc_init_proc_interface(path, header, ids, show) do {} while (0) | |
91 | #endif | |
1da177e4 | 92 | |
73ea4130 KK |
93 | #define IPC_SEM_IDS 0 |
94 | #define IPC_MSG_IDS 1 | |
95 | #define IPC_SHM_IDS 2 | |
96 | ||
ce621f5b | 97 | #define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER) |
03f59566 | 98 | #define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER) |
daf948c7 | 99 | #define IPCID_SEQ_MAX min_t(int, INT_MAX/SEQ_MULTIPLIER, USHRT_MAX) |
ce621f5b | 100 | |
d9a605e4 | 101 | /* must be called with ids->rwsem acquired for writing */ |
7ca7e564 | 102 | int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int); |
3e148c79 | 103 | |
1da177e4 | 104 | /* must be called with both locks acquired. */ |
7ca7e564 | 105 | void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *); |
1da177e4 | 106 | |
0cfb6aee GK |
107 | /* must be called with both locks acquired. */ |
108 | void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *); | |
109 | ||
f4566f04 | 110 | /* must be called with ipcp locked */ |
b0e77598 | 111 | int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg); |
1da177e4 | 112 | |
15df03c8 DB |
113 | /** |
114 | * ipc_get_maxid - get the last assigned id | |
115 | * @ids: ipc identifier set | |
116 | * | |
117 | * Called with ipc_ids.rwsem held for reading. | |
118 | */ | |
119 | static inline int ipc_get_maxid(struct ipc_ids *ids) | |
120 | { | |
121 | if (ids->in_use == 0) | |
122 | return -1; | |
123 | ||
124 | if (ids->in_use == IPCMNI) | |
125 | return IPCMNI - 1; | |
126 | ||
127 | return ids->max_id; | |
128 | } | |
129 | ||
1da177e4 LT |
130 | /* |
131 | * For allocation that need to be freed by RCU. | |
132 | * Objects are reference counted, they start with reference count 1. | |
133 | * getref increases the refcount, the putref call that reduces the recount | |
134 | * to 0 schedules the rcu destruction. Caller must guarantee locking. | |
62b49c99 MS |
135 | * |
136 | * refcount is initialized by ipc_addid(), before that point call_rcu() | |
137 | * must be used. | |
1da177e4 | 138 | */ |
dba4cdd3 MS |
139 | int ipc_rcu_getref(struct kern_ipc_perm *ptr); |
140 | void ipc_rcu_putref(struct kern_ipc_perm *ptr, | |
141 | void (*func)(struct rcu_head *head)); | |
1da177e4 | 142 | |
023a5355 | 143 | struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int); |
55b7ae50 | 144 | struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id); |
1da177e4 LT |
145 | |
146 | void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out); | |
147 | void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out); | |
1efdb69b | 148 | int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out); |
444d0f62 DB |
149 | struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns, |
150 | struct ipc_ids *ids, int id, int cmd, | |
151 | struct ipc64_perm *perm, int extra_perm); | |
1da177e4 | 152 | |
c1d7e01d | 153 | #ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION |
46c0a8ca | 154 | /* On IA-64, we always use the "64-bit version" of the IPC structures. */ |
1da177e4 LT |
155 | # define ipc_parse_version(cmd) IPC_64 |
156 | #else | |
239521f3 | 157 | int ipc_parse_version(int *cmd); |
1da177e4 LT |
158 | #endif |
159 | ||
160 | extern void free_msg(struct msg_msg *msg); | |
4e9b45a1 | 161 | extern struct msg_msg *load_msg(const void __user *src, size_t len); |
4a674f34 | 162 | extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst); |
4e9b45a1 | 163 | extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len); |
7748dbfa | 164 | |
1b531f21 | 165 | static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid) |
023a5355 | 166 | { |
7bb4deff | 167 | return uid / SEQ_MULTIPLIER != ipcp->seq; |
023a5355 ND |
168 | } |
169 | ||
1ca7003a | 170 | static inline void ipc_lock_object(struct kern_ipc_perm *perm) |
023a5355 | 171 | { |
023a5355 ND |
172 | spin_lock(&perm->lock); |
173 | } | |
174 | ||
1ca7003a | 175 | static inline void ipc_unlock_object(struct kern_ipc_perm *perm) |
023a5355 ND |
176 | { |
177 | spin_unlock(&perm->lock); | |
023a5355 ND |
178 | } |
179 | ||
1ca7003a | 180 | static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm) |
16df3674 | 181 | { |
1ca7003a DB |
182 | assert_spin_locked(&perm->lock); |
183 | } | |
184 | ||
1ca7003a DB |
185 | static inline void ipc_unlock(struct kern_ipc_perm *perm) |
186 | { | |
cf9d5d78 | 187 | ipc_unlock_object(perm); |
1ca7003a DB |
188 | rcu_read_unlock(); |
189 | } | |
190 | ||
0f3d2b01 RA |
191 | /* |
192 | * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths | |
193 | * where the respective ipc_ids.rwsem is not being held down. | |
194 | * Checks whether the ipc object is still around or if it's gone already, as | |
195 | * ipc_rmid() may have already freed the ID while the ipc lock was spinning. | |
196 | * Needs to be called with kern_ipc_perm.lock held -- exception made for one | |
197 | * checkpoint case at sys_semtimedop() as noted in code commentary. | |
198 | */ | |
199 | static inline bool ipc_valid_object(struct kern_ipc_perm *perm) | |
200 | { | |
72a8ff2f | 201 | return !perm->deleted; |
0f3d2b01 RA |
202 | } |
203 | ||
4d2bff5e | 204 | struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id); |
b2d75cdd | 205 | int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, |
eb66ec44 | 206 | const struct ipc_ops *ops, struct ipc_params *params); |
665c7741 AD |
207 | void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, |
208 | void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)); | |
553f770e AV |
209 | |
210 | #ifdef CONFIG_COMPAT | |
211 | #include <linux/compat.h> | |
212 | struct compat_ipc_perm { | |
213 | key_t key; | |
214 | __compat_uid_t uid; | |
215 | __compat_gid_t gid; | |
216 | __compat_uid_t cuid; | |
217 | __compat_gid_t cgid; | |
218 | compat_mode_t mode; | |
219 | unsigned short seq; | |
220 | }; | |
221 | ||
c0ebccb6 AV |
222 | void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *); |
223 | void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *); | |
224 | int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *); | |
225 | int get_compat_ipc64_perm(struct ipc64_perm *, | |
226 | struct compat_ipc64_perm __user *); | |
227 | ||
553f770e AV |
228 | static inline int compat_ipc_parse_version(int *cmd) |
229 | { | |
230 | #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION | |
231 | int version = *cmd & IPC_64; | |
232 | *cmd &= ~IPC_64; | |
233 | return version; | |
234 | #else | |
235 | return IPC_64; | |
236 | #endif | |
237 | } | |
238 | #endif | |
1da177e4 | 239 | #endif |