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/* CWirc - X-Chat plugin for sending and receiving raw morse code over IRC
(c) Pierre-Philippe Coupard - 18/06/2003
IPC routines
This program is distributed under the terms of the GNU General Public License
See the COPYING file for details
*/
#include <unistd.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include "ipc.h"
/* Create a semaphore set. */
int cwirc_sem_create(int key,int nb_sems)
{
struct sembuf sops;
int semid;
int i;
/* Create the semaphore set */
if((semid=semget(key,nb_sems,IPC_CREAT | 0600))==-1)
return(-1);
/* Wait for the semaphore to reach 1 */
for(i=0;i<nb_sems;i++)
{
sops.sem_num=i;
sops.sem_op=1; /* wait for semaphore flag to become 1 */
sops.sem_flg=SEM_UNDO;
if(semop(semid,&sops,1)==-1)
{
semctl(semid,0,IPC_RMID,0);
semid=-1;
return(-1);
}
}
return(semid);
}
/* Decrement a semaphore */
int cwirc_sem_dec(int semid,int semnum)
{
struct sembuf sops;
sops.sem_num=semnum;
sops.sem_op=-1; /* decrement semaphore == P() */
sops.sem_flg=SEM_UNDO;
if(semop(semid,&sops,1)==-1)
return(-1);
return(0);
}
/* Increment a semaphore */
int cwirc_sem_inc(int semid,int semnum)
{
struct sembuf sops;
sops.sem_num=semnum;
sops.sem_op=1; /* increment semaphore == V() */
sops.sem_flg=SEM_UNDO;
if(semop(semid,&sops,1)==-1)
return(-1);
return(0);
}
/* Destroy the semaphore */
int cwirc_sem_destroy(int semid)
{
if(semid<0 || semctl(semid,0,IPC_RMID,0)==-1)
return(-1);
return(0);
}
/* Allocate a shared memory block. Return code :
shared memory id
-1 : error allocating the shared memory */
int cwirc_shm_alloc(int key,int size)
{
return(shmget(key,size,IPC_CREAT | 0600));
}
/* Attach the shared memory block. Return code :
pointer to the shared memory block
-1 : error attaching to the shared memory block */
void *cwirc_shm_attach(int shmid)
{
return(shmat(shmid,NULL,0));
}
/* Detach the shared memory block. */
int cwirc_shm_detach(void *shm)
{
return(shmdt(shm));
}
/* Free the shared memory block */
int cwirc_shm_free(int shmid)
{
if(shmid<0 || shmctl(shmid,IPC_RMID,0)==-1)
return(-1);
return(0);
}
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