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/*
* linux/ipc/util.h
* Copyright (C) 1999 Christoph Rohland
*
* ipc helper functions (c) 1999 Manfred Spraul <manfreds@colorfullife.com>
*/
#define USHRT_MAX 0xffff
#define SEQ_MULTIPLIER (IPCMNI)
void sem_init (void);
void msg_init (void);
void shm_init (void);
struct ipc_ids {
int size;
int in_use;
int max_id;
unsigned short seq;
unsigned short seq_max;
struct semaphore sem;
spinlock_t ary;
struct ipc_id* entries;
};
struct ipc_id {
struct ipc_perm* p;
};
void __init ipc_init_ids(struct ipc_ids* ids, int size);
/* must be called with ids->sem acquired.*/
int ipc_findkey(struct ipc_ids* ids, key_t key);
int ipc_addid(struct ipc_ids* ids, struct ipc_perm* new, int size);
/* must be called with both locks acquired. */
struct ipc_perm* ipc_rmid(struct ipc_ids* ids, int id);
int ipcperms (struct ipc_perm *ipcp, short flg);
/* for rare, potentially huge allocations.
* both function can sleep
*/
void* ipc_alloc(int size);
void ipc_free(void* ptr, int size);
extern inline void ipc_lockall(struct ipc_ids* ids)
{
spin_lock(&ids->ary);
}
extern inline struct ipc_perm* ipc_get(struct ipc_ids* ids, int id)
{
struct ipc_perm* out;
int lid = id % SEQ_MULTIPLIER;
if(lid > ids->size)
return NULL;
out = ids->entries[lid].p;
return out;
}
extern inline void ipc_unlockall(struct ipc_ids* ids)
{
spin_unlock(&ids->ary);
}
extern inline struct ipc_perm* ipc_lock(struct ipc_ids* ids, int id)
{
struct ipc_perm* out;
int lid = id % SEQ_MULTIPLIER;
if(lid > ids->size)
return NULL;
spin_lock(&ids->ary);
out = ids->entries[lid].p;
if(out==NULL)
spin_unlock(&ids->ary);
return out;
}
extern inline void ipc_unlock(struct ipc_ids* ids, int id)
{
spin_unlock(&ids->ary);
}
extern inline int ipc_buildid(struct ipc_ids* ids, int id, int seq)
{
return SEQ_MULTIPLIER*seq + id;
}
extern inline int ipc_checkid(struct ipc_ids* ids, struct ipc_perm* ipcp, int uid)
{
if(uid/SEQ_MULTIPLIER != ipcp->seq)
return 1;
return 0;
}
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