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 #define USHRT_MAX 0xffff
   9 #define SEQ_MULTIPLIER  (IPCMNI)
  10
  11 void sem_init (void);
  12 void msg_init (void);
  13 void shm_init (void);
  14
  15 struct ipc_ids {
  16         int size;
  17         int in_use;
  18         int max_id;
  19         unsigned short seq;
  20         unsigned short seq_max;
  21         struct semaphore sem;
  22         spinlock_t ary;
  23         struct ipc_id* entries;
  24 };
  25
  26 struct ipc_id {
  27         struct kern_ipc_perm* p;
  28 };
  29
  30
  31 void __init ipc_init_ids(struct ipc_ids* ids, int size);
  32
  33 /* must be called with ids->sem acquired.*/
  34 int ipc_findkey(struct ipc_ids* ids, key_t key);
  35 int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size);
  36
  37 /* must be called with both locks acquired. */
  38 struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id);
  39
  40 int ipcperms (struct kern_ipc_perm *ipcp, short flg);
  41
  42 /* for rare, potentially huge allocations.
  43  * both function can sleep
  44  */
  45 void* ipc_alloc(int size);
  46 void ipc_free(void* ptr, int size);
  47
  48 extern inline void ipc_lockall(struct ipc_ids* ids)
  49 {
  50         spin_lock(&ids->ary);
  51 }
  52
  53 extern inline struct kern_ipc_perm* ipc_get(struct ipc_ids* ids, int id)
  54 {
  55         struct kern_ipc_perm* out;
  56         int lid = id % SEQ_MULTIPLIER;
  57         if(lid > ids->size)
  58                 return NULL;
  59
  60         out = ids->entries[lid].p;
  61         return out;
  62 }
  63
  64 extern inline void ipc_unlockall(struct ipc_ids* ids)
  65 {
  66         spin_unlock(&ids->ary);
  67 }
  68 extern inline struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id)
  69 {
  70         struct kern_ipc_perm* out;
  71         int lid = id % SEQ_MULTIPLIER;
  72         if(lid > ids->size)
  73                 return NULL;
  74
  75         spin_lock(&ids->ary);
  76         out = ids->entries[lid].p;
  77         if(out==NULL)
  78                 spin_unlock(&ids->ary);
  79         return out;
  80 }
  81
  82 extern inline void ipc_unlock(struct ipc_ids* ids, int id)
  83 {
  84         spin_unlock(&ids->ary);
  85 }
  86
  87 extern inline int ipc_buildid(struct ipc_ids* ids, int id, int seq)
  88 {
  89         return SEQ_MULTIPLIER*seq + id;
  90 }
  91
  92 extern inline int ipc_checkid(struct ipc_ids* ids, struct kern_ipc_perm* ipcp, int uid)
  93 {
  94         if(uid/SEQ_MULTIPLIER != ipcp->seq)
  95                 return 1;
  96         return 0;
  97 }
  98
  99 void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out);
 100 void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out);
 101
 102 #ifdef __ia64__
 103   /* On IA-64, we always use the "64-bit version" of the IPC structures.  */
 104 # define ipc_parse_version(cmd) IPC_64
 105 #else
 106 int ipc_parse_version (int *cmd);
 107 #endif