boinc/lib/synch.C

114 lines
2.5 KiB
C

// Berkeley Open Infrastructure for Network Computing
// http://boinc.berkeley.edu
// Copyright (C) 2005 University of California
//
// This is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation;
// either version 2.1 of the License, or (at your option) any later version.
//
// This software is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU Lesser General Public License for more details.
//
// To view the GNU Lesser General Public License visit
// http://www.gnu.org/copyleft/lesser.html
// or write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
// interfaces for accessing sempahores
#include "config.h"
#include <cstdio>
#include <cstring>
#include "error_numbers.h"
#include "synch.h"
#ifdef _USING_FCGI_
#include "fcgi_stdio.h"
#endif
union SEMUN {
int val;
struct semid_ds *buf;
unsigned short int *arra;
struct seminfo *__buf;
};
int create_semaphore(key_t key){
int id, retval;
SEMUN s;
id = semget(key, 1, IPC_CREAT|IPC_EXCL|0777);
if (id < 0) {
return ERR_SEMGET;
}
memset(&s, 0, sizeof(s));
s.val = 1;
retval = semctl(id, 0, SETVAL, s);
if (retval) {
return ERR_SEMCTL;
}
return 0;
}
int destroy_semaphore(key_t key){
int id, retval;
id = semget(key, 0, 0);
if (id < 0) {
return ERR_SEMGET;
}
retval = semctl(id, 1, IPC_RMID, 0);
if (retval) {
return ERR_SEMCTL;
}
return 0;
}
int lock_semaphore(key_t key) {
struct sembuf s;
int id, retval;
id = semget(key, 0, 0);
if (id < 0) {
return ERR_SEMGET;
}
s.sem_num = 0;
s.sem_op = -1;
s.sem_flg = SEM_UNDO;
retval = semop(id, &s, 1);
if (retval) {
return ERR_SEMOP;
}
return 0;
}
int unlock_semaphore(key_t key) {
struct sembuf s;
int id, retval;
id = semget(key, 0, 0);
if (id < 0) {
return ERR_SEMGET;
}
s.sem_num = 0;
s.sem_op = 1;
s.sem_flg = SEM_UNDO;
retval = semop(id, &s, 1);
if (retval) {
return ERR_SEMOP;
}
return 0;
}
int get_key(char* path, int id, key_t& key) {
key = ftok(path, id);
if (key == (key_t)-1) return ERR_FTOK;
return 0;
}
const char *BOINC_RCSID_9412b586d1 = "$Id$";