Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/ipc/util.h

  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
 28 static inline void mq_clear_sbinfo(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
 41 static inline void sem_init_ns(struct ipc_namespace *ns) { }
 42 static inline void msg_init_ns(struct ipc_namespace *ns) { }
 43 static inline void shm_init_ns(struct ipc_namespace *ns) { }
 44 
 45 static inline void sem_exit_ns(struct ipc_namespace *ns) { }
 46 static inline void msg_exit_ns(struct ipc_namespace *ns) { }
 47 static inline void shm_exit_ns(struct ipc_namespace *ns) { }
 48 #endif
 49 
 50 struct ipc_rcu {
 51         struct rcu_head rcu;
 52         atomic_t refcount;
 53 } ____cacheline_aligned_in_smp;
 54 
 55 #define ipc_rcu_to_struct(p)  ((void *)(p+1))
 56 
 57 /*
 58  * Structure that holds the parameters needed by the ipc operations
 59  * (see after)
 60  */
 61 struct ipc_params {
 62         key_t key;
 63         int flg;
 64         union {
 65                 size_t size;    /* for shared memories */
 66                 int nsems;      /* for semaphores */
 67         } u;                    /* holds the getnew() specific param */
 68 };
 69 
 70 /*
 71  * Structure that holds some ipc operations. This structure is used to unify
 72  * the calls to sys_msgget(), sys_semget(), sys_shmget()
 73  *      . routine to call to create a new ipc object. Can be one of newque,
 74  *        newary, newseg
 75  *      . routine to call to check permissions for a new ipc object.
 76  *        Can be one of security_msg_associate, security_sem_associate,
 77  *        security_shm_associate
 78  *      . routine to call for an extra check if needed
 79  */
 80 struct ipc_ops {
 81         int (*getnew)(struct ipc_namespace *, struct ipc_params *);
 82         int (*associate)(struct kern_ipc_perm *, int);
 83         int (*more_checks)(struct kern_ipc_perm *, struct ipc_params *);
 84 };
 85 
 86 struct seq_file;
 87 struct ipc_ids;
 88 
 89 void ipc_init_ids(struct ipc_ids *);
 90 #ifdef CONFIG_PROC_FS
 91 void __init ipc_init_proc_interface(const char *path, const char *header,
 92                 int ids, int (*show)(struct seq_file *, void *));
 93 #else
 94 #define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
 95 #endif
 96 
 97 #define IPC_SEM_IDS     0
 98 #define IPC_MSG_IDS     1
 99 #define IPC_SHM_IDS     2
100 
101 #define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
102 #define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER)
103 #define IPCID_SEQ_MAX min_t(int, INT_MAX/SEQ_MULTIPLIER, USHRT_MAX)
104 
105 /* must be called with ids->rwsem acquired for writing */
106 int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
107 
108 /* must be called with ids->rwsem acquired for reading */
109 int ipc_get_maxid(struct ipc_ids *);
110 
111 /* must be called with both locks acquired. */
112 void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
113 
114 /* must be called with ipcp locked */
115 int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg);
116 
117 /* for rare, potentially huge allocations.
118  * both function can sleep
119  */
120 void *ipc_alloc(int size);
121 void ipc_free(void *ptr);
122 
123 /*
124  * For allocation that need to be freed by RCU.
125  * Objects are reference counted, they start with reference count 1.
126  * getref increases the refcount, the putref call that reduces the recount
127  * to 0 schedules the rcu destruction. Caller must guarantee locking.
128  */
129 void *ipc_rcu_alloc(int size);
130 int ipc_rcu_getref(void *ptr);
131 void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head));
132 void ipc_rcu_free(struct rcu_head *head);
133 
134 struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
135 struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);
136 
137 void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
138 void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
139 int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
140 struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns,
141                                              struct ipc_ids *ids, int id, int cmd,
142                                              struct ipc64_perm *perm, int extra_perm);
143 
144 #ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
145 /* On IA-64, we always use the "64-bit version" of the IPC structures.  */
146 # define ipc_parse_version(cmd) IPC_64
147 #else
148 int ipc_parse_version(int *cmd);
149 #endif
150 
151 extern void free_msg(struct msg_msg *msg);
152 extern struct msg_msg *load_msg(const void __user *src, size_t len);
153 extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst);
154 extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len);
155 
156 extern void recompute_msgmni(struct ipc_namespace *);
157 
158 static inline int ipc_buildid(int id, int seq)
159 {
160         return SEQ_MULTIPLIER * seq + id;
161 }
162 
163 static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
164 {
165         return uid / SEQ_MULTIPLIER != ipcp->seq;
166 }
167 
168 static inline void ipc_lock_object(struct kern_ipc_perm *perm)
169 {
170         spin_lock(&perm->lock);
171 }
172 
173 static inline void ipc_unlock_object(struct kern_ipc_perm *perm)
174 {
175         spin_unlock(&perm->lock);
176 }
177 
178 static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm)
179 {
180         assert_spin_locked(&perm->lock);
181 }
182 
183 static inline void ipc_unlock(struct kern_ipc_perm *perm)
184 {
185         ipc_unlock_object(perm);
186         rcu_read_unlock();
187 }
188 
189 /*
190  * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths
191  * where the respective ipc_ids.rwsem is not being held down.
192  * Checks whether the ipc object is still around or if it's gone already, as
193  * ipc_rmid() may have already freed the ID while the ipc lock was spinning.
194  * Needs to be called with kern_ipc_perm.lock held -- exception made for one
195  * checkpoint case at sys_semtimedop() as noted in code commentary.
196  */
197 static inline bool ipc_valid_object(struct kern_ipc_perm *perm)
198 {
199         return !perm->deleted;
200 }
201 
202 struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id);
203 int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
204                         const struct ipc_ops *ops, struct ipc_params *params);
205 void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
206                 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
207 #endif
208 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us