ipc/util.h

   1 /*
   2  * linux/ipc/util.h
   3  * Copyright (C) 1999 Christoph Rohland
   4  *
   5  * ipc helper functions (c) 1999 Manfred Spraul <manfreds@colorfullife.com>
   6  */
   7
   8 #ifndef _IPC_UTIL_H
   9 #define _IPC_UTIL_H
  10
  11 #define USHRT_MAX 0xffff
  12 #define SEQ_MULTIPLIER  (IPCMNI)
  13
  14 void sem_init (void);
  15 void msg_init (void);
  16 void shm_init (void);
  17
  18 struct ipc_ids {
  19         int size;
  20         int in_use;
  21         int max_id;
  22         unsigned short seq;
  23         unsigned short seq_max;
  24         struct semaphore sem;
  25         struct ipc_id* entries;
  26 };
  27
  28 struct ipc_id {
  29         struct kern_ipc_perm* p;
  30 };
  31
  32 void __init ipc_init_ids(struct ipc_ids* ids, int size);
  33
  34 /* must be called with ids->sem acquired.*/
  35 int ipc_findkey(struct ipc_ids* ids, key_t key);
  36 int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size);
  37
  38 /* must be called with both locks acquired. */
  39 struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id);
  40
  41 int ipcperms (struct kern_ipc_perm *ipcp, short flg);
  42
  43 /* for rare, potentially huge allocations.
  44  * both function can sleep
  45  */
  46 void* ipc_alloc(int size);
  47 void ipc_free(void* ptr, int size);
  48
  49 /*
  50  * For allocation that need to be freed by RCU.
  51  * Objects are reference counted, they start with reference count 1.
  52  * getref increases the refcount, the putref call that reduces the recount
  53  * to 0 schedules the rcu destruction. Caller must guarantee locking.
  54  */
  55 void* ipc_rcu_alloc(int size);
  56 void ipc_rcu_getref(void *ptr);
  57 void ipc_rcu_putref(void *ptr);
  58
  59 struct kern_ipc_perm* ipc_get(struct ipc_ids* ids, int id);
  60 struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id);
  61 void ipc_lock_by_ptr(struct kern_ipc_perm *ipcp);
  62 void ipc_unlock(struct kern_ipc_perm* perm);
  63 int ipc_buildid(struct ipc_ids* ids, int id, int seq);
  64 int ipc_checkid(struct ipc_ids* ids, struct kern_ipc_perm* ipcp, int uid);
  65
  66 void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
  67 void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
  68
  69 #if defined(__ia64__) || defined(__x86_64__) || defined(__hppa__)
  70   /* On IA-64, we always use the "64-bit version" of the IPC structures.  */
  71 # define ipc_parse_version(cmd) IPC_64
  72 #else
  73 int ipc_parse_version (int *cmd);
  74 #endif
  75
  76 extern void free_msg(struct msg_msg *msg);
  77 extern struct msg_msg *load_msg(const void __user *src, int len);
  78 extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
  79
  80 #endif