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/*-------------------------------------------------------------------------
*
* shm.c
* BeOS System V Shared Memory Emulation
*
* Copyright (c) 1999-2000, Cyril VELTER
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <stdio.h>
#include <OS.h>
/* Emulating SYS shared memory with beos areas. WARNING : fork clone
areas in copy on write mode */
/* Detach from a shared mem area based on its address */
int shmdt(char* shmaddr)
{
/* Find area id for this address */
area_id s;
s=area_for(shmaddr);
/* Delete area */
return delete_area(s);
}
/* Attach to an existing area */
int* shmat(int memId,int m1,int m2)
{
/* Get our team id */
thread_info thinfo;
team_info teinfo;
area_info ainfo;
get_thread_info(find_thread(NULL),&thinfo);
get_team_info(thinfo.team,&teinfo);
/* Get area teamid */
if (get_area_info(memId,&ainfo)!=B_OK)
printf("AREA %d Invalide\n",memId);
if (ainfo.team==teinfo.team)
{
/* the area is already in our address space, just return the address */
return (int*)ainfo.address;
}
else
{
/* the area is not in our address space, clone it before and return the address */
area_id narea;
narea = clone_area(ainfo.name,&(ainfo.address),B_CLONE_ADDRESS,B_READ_AREA | B_WRITE_AREA,memId);
get_area_info(narea,&ainfo);
return (int*)ainfo.address;
}
}
/* Control a shared mem area : Used only to delete it */
int shmctl(int shmid,int flag, struct shmid_ds* dummy)
{
/* Delete the area */
delete_area(shmid);
return 0;
}
/* Get an area based on the IPC key */
int shmget(int memKey,int size,int flag)
{
char nom[50];
void* Address;
area_id parea;
/* Area name */
sprintf(nom,"SYSV_IPC_SHM : %d",memKey);
/* Find area */
parea=find_area(nom);
/* area exist, just return its id */
if (parea!=B_NAME_NOT_FOUND)
{
return parea;
}
/* area does not exist and no creation is requested : error */
if (flag==0)
{
return -1;
}
/* area does not exist and its creation is requested, create it (be sure to have a 4ko multiple size */
return create_area(nom,&Address,B_ANY_ADDRESS,((size/4096)+1)*4096,B_NO_LOCK,B_READ_AREA | B_WRITE_AREA);
}
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