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 #define USHRT_MAX 0xffff
  14 #define SEQ_MULTIPLIER  (IPCMNI)
  15
  16 void sem_init (void);
  17 void msg_init (void);
  18 void shm_init (void);
  19
  20 int sem_init_ns(struct ipc_namespace *ns);
  21 int msg_init_ns(struct ipc_namespace *ns);
  22 int shm_init_ns(struct ipc_namespace *ns);
  23
  24 void sem_exit_ns(struct ipc_namespace *ns);
  25 void msg_exit_ns(struct ipc_namespace *ns);
  26 void shm_exit_ns(struct ipc_namespace *ns);
  27
  28 struct ipc_id_ary {
  29         int size;
  30         struct kern_ipc_perm *p[0];
  31 };
  32
  33 struct ipc_ids {
  34         int in_use;
  35         int max_id;
  36         unsigned short seq;
  37         unsigned short seq_max;
  38         struct mutex mutex;
  39         struct ipc_id_ary nullentry;
  40         struct ipc_id_ary* entries;
  41 };
  42
  43 struct seq_file;
  44
  45 void ipc_init_ids(struct ipc_ids *ids, int size);
  46 #ifdef CONFIG_PROC_FS
  47 void __init ipc_init_proc_interface(const char *path, const char *header,
  48                 int ids, int (*show)(struct seq_file *, void *));
  49 #else
  50 #define ipc_init_proc_interface(path, header, ids, show) do {} while (0)
  51 #endif
  52
  53 #define IPC_SEM_IDS     0
  54 #define IPC_MSG_IDS     1
  55 #define IPC_SHM_IDS     2
  56
  57 /* must be called with ids->mutex acquired.*/
  58 int ipc_findkey(struct ipc_ids* ids, key_t key);
  59 int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size);
  60
  61 /* must be called with both locks acquired. */
  62 struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id);
  63
  64 int ipcperms (struct kern_ipc_perm *ipcp, short flg);
  65
  66 /* for rare, potentially huge allocations.
  67  * both function can sleep
  68  */
  69 void* ipc_alloc(int size);
  70 void ipc_free(void* ptr, int size);
  71
  72 /*
  73  * For allocation that need to be freed by RCU.
  74  * Objects are reference counted, they start with reference count 1.
  75  * getref increases the refcount, the putref call that reduces the recount
  76  * to 0 schedules the rcu destruction. Caller must guarantee locking.
  77  */
  78 void* ipc_rcu_alloc(int size);
  79 void ipc_rcu_getref(void *ptr);
  80 void ipc_rcu_putref(void *ptr);
  81
  82 static inline void __ipc_fini_ids(struct ipc_ids *ids,
  83                 struct ipc_id_ary *entries)
  84 {
  85         if (entries != &ids->nullentry)
  86                 ipc_rcu_putref(entries);
  87 }
  88
  89 static inline void ipc_fini_ids(struct ipc_ids *ids)
  90 {
  91         __ipc_fini_ids(ids, ids->entries);
  92 }
  93
  94 struct kern_ipc_perm* ipc_get(struct ipc_ids* ids, int id);
  95 struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id);
  96 void ipc_lock_by_ptr(struct kern_ipc_perm *ipcp);
  97 void ipc_unlock(struct kern_ipc_perm* perm);
  98 int ipc_buildid(struct ipc_ids* ids, int id, int seq);
  99 int ipc_checkid(struct ipc_ids* ids, struct kern_ipc_perm* ipcp, int uid);
 100
 101 void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
 102 void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
 103
 104 #if defined(__ia64__) || defined(__x86_64__) || defined(__hppa__) || defined(__XTENSA__)
 105   /* On IA-64, we always use the "64-bit version" of the IPC structures.  */
 106 # define ipc_parse_version(cmd) IPC_64
 107 #else
 108 int ipc_parse_version (int *cmd);
 109 #endif
 110
 111 extern void free_msg(struct msg_msg *msg);
 112 extern struct msg_msg *load_msg(const void __user *src, int len);
 113 extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
 114
 115 #endif