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/err.h>
 14 
 15 #define SEQ_MULTIPLIER  (IPCMNI)
 16 
 17 void sem_init (void);
 18 void msg_init (void);
 19 void shm_init (void);
 20 
 21 struct ipc_namespace;
 22 
 23 void sem_init_ns(struct ipc_namespace *ns);
 24 void msg_init_ns(struct ipc_namespace *ns);
 25 void 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 
 31 /*
 32  * Structure that holds the parameters needed by the ipc operations
 33  * (see after)
 34  */
 35 struct ipc_params {
 36         key_t key;
 37         int flg;
 38         union {
 39                 size_t size;    /* for shared memories */
 40                 int nsems;      /* for semaphores */
 41         } u;                    /* holds the getnew() specific param */
 42 };
 43 
 44 /*
 45  * Structure that holds some ipc operations. This structure is used to unify
 46  * the calls to sys_msgget(), sys_semget(), sys_shmget()
 47  *      . routine to call to create a new ipc object. Can be one of newque,
 48  *        newary, newseg
 49  *      . routine to call to check permissions for a new ipc object.
 50  *        Can be one of security_msg_associate, security_sem_associate,
 51  *        security_shm_associate
 52  *      . routine to call for an extra check if needed
 53  */
 54 struct ipc_ops {
 55         int (*getnew) (struct ipc_namespace *, struct ipc_params *);
 56         int (*associate) (struct kern_ipc_perm *, int);
 57         int (*more_checks) (struct kern_ipc_perm *, struct ipc_params *);
 58 };
 59 
 60 struct seq_file;
 61 struct ipc_ids;
 62 
 63 void ipc_init_ids(struct ipc_ids *);
 64 #ifdef CONFIG_PROC_FS
 65 void __init ipc_init_proc_interface(const char *path, const char *header,
 66                 int ids, int (*show)(struct seq_file *, void *));
 67 #else
 68 #define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
 69 #endif
 70 
 71 #define IPC_SEM_IDS     0
 72 #define IPC_MSG_IDS     1
 73 #define IPC_SHM_IDS     2
 74 
 75 #define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
 76 
 77 /* must be called with ids->rw_mutex acquired for writing */
 78 int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);
 79 
 80 /* must be called with ids->rw_mutex acquired for reading */
 81 int ipc_get_maxid(struct ipc_ids *);
 82 
 83 /* must be called with both locks acquired. */
 84 void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
 85 
 86 /* must be called with ipcp locked */
 87 int ipcperms(struct kern_ipc_perm *ipcp, short flg);
 88 
 89 /* for rare, potentially huge allocations.
 90  * both function can sleep
 91  */
 92 void* ipc_alloc(int size);
 93 void ipc_free(void* ptr, int size);
 94 
 95 /*
 96  * For allocation that need to be freed by RCU.
 97  * Objects are reference counted, they start with reference count 1.
 98  * getref increases the refcount, the putref call that reduces the recount
 99  * to 0 schedules the rcu destruction. Caller must guarantee locking.
100  */
101 void* ipc_rcu_alloc(int size);
102 void ipc_rcu_getref(void *ptr);
103 void ipc_rcu_putref(void *ptr);
104 
105 struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
106 
107 void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
108 void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
109 void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out);
110 struct kern_ipc_perm *ipcctl_pre_down(struct ipc_ids *ids, int id, int cmd,
111                                       struct ipc64_perm *perm, int extra_perm);
112 
113 #if defined(__ia64__) || defined(__x86_64__) || defined(__hppa__) || defined(__XTENSA__)
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);
123 
124 extern void recompute_msgmni(struct ipc_namespace *);
125 
126 static inline int ipc_buildid(int id, int seq)
127 {
128         return SEQ_MULTIPLIER * seq + id;
129 }
130 
131 /*
132  * Must be called with ipcp locked
133  */
134 static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
135 {
136         if (uid / SEQ_MULTIPLIER != ipcp->seq)
137                 return 1;
138         return 0;
139 }
140 
141 static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
142 {
143         rcu_read_lock();
144         spin_lock(&perm->lock);
145 }
146 
147 static inline void ipc_unlock(struct kern_ipc_perm *perm)
148 {
149         spin_unlock(&perm->lock);
150         rcu_read_unlock();
151 }
152 
153 struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id);
154 int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
155                         struct ipc_ops *ops, struct ipc_params *params);
156 
157 #endif
158
This page was automatically generated by LXR 0.3.1. • Linux is a registered trademark of Linus Torvalds
Linux Cross Reference

Free Electrons

Linux/ipc/util.h
