Zabbix

/*

** Copyright (C) 2001-2025 Zabbix SIA

**

** This program is free software: you can redistribute it and/or modify it under the terms of

** the GNU Affero General Public License as published by the Free Software Foundation, version 3.

**

** This program 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 Affero General Public License for more details.

**

** You should have received a copy of the GNU Affero General Public License along with this program.

** If not, see <https://www.gnu.org/licenses/>.

**/

​

#include "zbxmutexs.h"

​

#ifdef _WINDOWS

#   include "zbxsysinfo.h"

#   include "zbxlog.h"

#else

#ifdef HAVE_PTHREAD_PROCESS_SHARED

typedef struct

{

    pthread_mutex_t     mutexes[ZBX_MUTEX_COUNT];

    pthread_rwlock_t    rwlocks[ZBX_RWLOCK_COUNT];

}

zbx_shared_lock_t;

​

static zbx_shared_lock_t    *shared_lock;

static int          shm_id, locks_disabled;

#else

#   if !HAVE_SEMUN

        union semun

        {

            int         val;    /* value for SETVAL */

            struct semid_ds     *buf;   /* buffer for IPC_STAT & IPC_SET */

            unsigned short int  *array; /* array for GETALL & SETALL */

            struct seminfo      *__buf; /* buffer for IPC_INFO */

        };

​

#       undef HAVE_SEMUN

#       define HAVE_SEMUN 1

#   endif   /* HAVE_SEMUN */

​

#   include "zbxcfg.h"

#   include "zbxthreads.h"

​

    static int      ZBX_SEM_LIST_ID = -1;

    static unsigned char    mutexes;

#endif

​

/******************************************************************************

 *                                                                            *

 * Purpose: if pthread mutexes and read-write locks can be shared between     *

 *          processes then create them, otherwise fallback to System V        *

 *          semaphore operations                                              *

 *                                                                            *

 * Parameters: error - [OUT] dynamically allocated memory with error message. *

 *                                                                            *

 * Return value: SUCCEED if mutexes successfully created, otherwise FAIL      *

 *                                                                            *

 ******************************************************************************/

int zbx_locks_create(char **error)

{

#ifdef HAVE_PTHREAD_PROCESS_SHARED

    int         i;

    pthread_mutexattr_t mta;

    pthread_rwlockattr_t    rwa;

​

    if (-1 == (shm_id = shmget(IPC_PRIVATE, ZBX_SIZE_T_ALIGN8(sizeof(zbx_shared_lock_t)),

            IPC_CREAT | IPC_EXCL | 0600)))

    {

        *error = zbx_dsprintf(*error, "cannot allocate shared memory for locks");

        return FAIL;

    }

​

    if ((void *)(-1) == (shared_lock = (zbx_shared_lock_t *)shmat(shm_id, NULL, 0)))

    {

        *error = zbx_dsprintf(*error, "cannot attach shared memory for locks: %s", zbx_strerror(errno));

        return FAIL;

    }

​

    memset(shared_lock, 0, sizeof(zbx_shared_lock_t));

​

    /* immediately mark the new shared memory for destruction after attaching to it */

    if (-1 == shmctl(shm_id, IPC_RMID, 0))

    {

        *error = zbx_dsprintf(*error, "cannot mark the new shared memory for destruction: %s",

                zbx_strerror(errno));

        return FAIL;

    }