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_id_ary {
  19         int size;
  20         struct kern_ipc_perm *p[0];
  21 };
  22
  23 struct ipc_ids {
  24         int in_use;
  25         int max_id;
  26         unsigned short seq;
  27         unsigned short seq_max;
  28         struct semaphore sem;
  29         struct ipc_id_ary nullentry;
  30         struct ipc_id_ary* entries;
  31 };
  32
  33 void __init ipc_init_ids(struct ipc_ids* ids, int size);
  34
  35 /* must be called with ids->sem acquired.*/
  36 int ipc_findkey(struct ipc_ids* ids, key_t key);
  37 int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size);
  38
  39 /* must be called with both locks acquired. */
  40 struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id);
  41
  42 int ipcperms (struct kern_ipc_perm *ipcp, short flg);
  43
  44 /* for rare, potentially huge allocations.
  45  * both function can sleep
  46  */
  47 void* ipc_alloc(int size);
  48 void ipc_free(void* ptr, int size);
  49
  50 /*
  51  * For allocation that need to be freed by RCU.
  52  * Objects are reference counted, they start with reference count 1.
  53  * getref increases the refcount, the putref call that reduces the recount
  54  * to 0 schedules the rcu destruction. Caller must guarantee locking.
  55  */
  56 void* ipc_rcu_alloc(int size);
  57 void ipc_rcu_getref(void *ptr);
  58 void ipc_rcu_putref(void *ptr);
  59
  60 struct kern_ipc_perm* ipc_get(struct ipc_ids* ids, int id);
  61 struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id);
  62 void ipc_lock_by_ptr(struct kern_ipc_perm *ipcp);
  63 void ipc_unlock(struct kern_ipc_perm* perm);
  64 int ipc_buildid(struct ipc_ids* ids, int id, int seq);
  65 int ipc_checkid(struct ipc_ids* ids, struct kern_ipc_perm* ipcp, int uid);
  66
  67 void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
  68 void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
  69
  70 #if defined(__ia64__) || defined(__x86_64__) || defined(__hppa__)
  71   /* On IA-64, we always use the "64-bit version" of the IPC structures.  */
  72 # define ipc_parse_version(cmd) IPC_64
  73 #else
  74 int ipc_parse_version (int *cmd);
  75 #endif
  76
  77 extern void free_msg(struct msg_msg *msg);
  78 extern struct msg_msg *load_msg(const void __user *src, int len);
  79 extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
  80
  81 #endif