lc_shmem.c

open source for car navigation in linux

/*
 * Copyright (C) 2002 Ricardo Arroyo <[e-mail]>
 *
 * This code may be used under the terms of Version 2 of the GPL,
 * read the file COPYING for details.
 *
 */
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <ulimit.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>

#include "lc_syslog.h"
#include "lc_debug.h"

#include "lc_shmem.h"

/*__________________________________________________________________________*/
/* FUNCTION                pCreateShMem(key_t SHmKey, int iLong)            */
/* DESCRIPTION             Creates a shared memory area asociated with      */
/*                         given SHmKey and iLong bytes long                */
/*			                                                    */
/* INPUT PARAMETERS        SHmKey       Shared Memory Key                   */
/*                                      (use ftok to get it)                */
/*                                                                          */
/*                         iLong        Length in bytes of memory area      */
/*                                                                          */
/* OUTPUT PARAMETERS       pointer to shared memory area                    */
/* 			                                                    */
/*__________________________________________________________________________*/

void* pCreateShMem(key_t SHmKey, int iLong)
{

void* punt;
int shm_id;

   if (iDebug & DEP_SHMEM)
   {
      fprintf(stderr,"pCreateShMem: break = %lx, ulimit = %lx\n",(long) sbrk(0),(long)ulimit(3,0L));
   }

   if ((shm_id = shmget(SHmKey, iLong, 0666 | IPC_CREAT)) == -1)
   {
      vLC_syslog(LCLOG_ERR_SHMGET, "pCreateShMem", errno);
      return (NULL);
   }
   else if ((int)(punt = shmat(shm_id, 0, 0666)) == -1)
   {
      vLC_syslog(LCLOG_ERR_SHMAT, "pCreateShMem", errno);
      return (NULL);
   }
   if (iDebug & DEP_SHMEM)
   {
      fprintf(stderr,"pCreateShMem: Shared Memory attached, Key = %ld, shm_id = %d\n",(long)SHmKey, iLong);
      fprintf(stderr,"pCreateShMem: break = %lx, shm = %lx, ulimit = %lx\n",(long) sbrk(0),(long)punt,(long)ulimit(3,0L));
   }
   return(punt);
}


/*__________________________________________________________________________*/
/* FUNCTION                pAssignShMem(key_t SHmKey, int iLong)            */
/* DESCRIPTION             Attachs a previous created shared memory area    */
/*                         asociated with given SHmKey and iLong bytes long */
/*			                                                    */
/* INPUT PARAMETERS        SHmKey       Shared Memory Key                   */
/*                                      (use ftok to get it)                */
/*                                                                          */
/*                         iLong        Length in bytes of memory area      */
/*                                                                          */
/* OUTPUT PARAMETERS       pointer to shared memory area                    */
/* 			                                                    */
/*__________________________________________________________________________*/

void* pAssignShMem(key_t SHmKey, int iLong)
{

void* punt;
int shm_id;

   if (iDebug & DEP_SHMEM)
   {
      fprintf(stderr,"pAssignShMem: break = %lx, ulimit = %lx\n",(long)sbrk(0),(long)ulimit(3,0L));
   }

   if ((shm_id = shmget(SHmKey, iLong, 0666 | IPC_CREAT)) == -1)
   {
      vLC_syslog(LCLOG_ERR_SHMGET, "pAssignShMem", errno);
      return (NULL);
   }
   else if ((int)(punt = shmat(shm_id, 0, 0666)) == -1)
   {
      vLC_syslog(LCLOG_ERR_SHMAT, "pAssignShMem", errno);
      return (NULL);
   }
   if (iDebug & DEP_SHMEM)
   {
      fprintf(stderr,"pAssignShMem: Shared Memory attached, Key = %ld, shm_id = %d\n",(long)SHmKey, iLong);
      fprintf(stderr,"pAssignShMem: break = %lx, shm = %lx, ulimit = %lx\n",(long)sbrk(0),(long)punt,(long)ulimit(3,0L));
   }
   return(punt);
}


/*__________________________________________________________________________*/
/* FUNCTION                iDetachShMem (punt)                              */
/*                                                                          */
/* INPUT PARAMETERS        punt       pointer to shared memory area         */
/*                                                                          */
/* OUTPUT PARAMETERS       0 = memory dettached                             */
/*                        -1 = error (chech errno)                          */
/* 			                                                    */
/*__________________________________________________________________________*/
int iDetachShMem(void *punt)
{
int	res;

   if (iDebug & DEP_SHMEM)
   {
      fprintf(stderr,"iDetachShMem: break = %lx, shm = %lx, ulimit = %lx\n",(long)sbrk(0), (long)punt,(long)ulimit(3,0L));
   }

	res = shmdt(punt);

   if (iDebug & DEP_SHMEM)
   {
      fprintf(stderr,"iDetachShMem: break = %lx, ulimit = %lx\n",(long) sbrk(0),(long)ulimit(3,0L));
   }
   return(res);
}


/*__________________________________________________________________________*/
/* FUNCTION                iDelShMem (key_t ShmKey)                         */
/*                                                                          */
/* INPUT PARAMETERS        SHmKey       Shared Memory Key                   */
/*                                      (use ftok to get it)                */
/*                                                                          */
/* OUTPUT PARAMETERS       0 = memory dettached                             */
/*                        -1 = error (chech errno)                          */
/* 			                                                    */
/*__________________________________________________________________________*/
int iDelShMem( key_t SHmKey)
{

int shm_id;
struct shmid_ds shmstr;
int res;


   if ((shm_id = shmget(SHmKey,0,0666)) != -1)
   {
      if ((res = shmctl(shm_id, IPC_RMID, &shmstr)) == -1)
      {
         vLC_syslog(LCLOG_ERR_SHMRM, "iDelShMem", errno);
         return (res);
      }
      return(0);
   }
   vLC_syslog(LCLOG_ERR_SHMRM,"iDelShMem", 0);
   return(-1);
}