/* $Id: kLdrHlpSem.c 2944 2007-01-13 15:55:40Z bird $ */
/** @file
 *
 * kLdr - The Dynamic Loader, Semaphore Helper Functions.
 *
 * Copyright (c) 2006 knut st. osmundsen <bird-kbuild-src@anduin.net>
 *
 *
 * This file is part of kLdr.
 *
 * kLdr is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * kLdr 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with kLdr; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */


/*******************************************************************************
*   Header Files                                                               *
*******************************************************************************/
#ifdef __OS2__
# define INCL_BASE
# define INCL_ERRORS
# include <os2.h>
#elif defined(__WIN__)
# include <Windows.h>
#else
# error "port me"
#endif

#include <kLdr.h>
#include "kLdrHlp.h"


/*******************************************************************************
*   Global Variables                                                           *
*******************************************************************************/
#ifdef __OS2__
/** The loader sempahore. */
static HMTX             g_hmtx;

#elif defined(__WIN__)
/** The loader sempahore. */
static CRITICAL_SECTION g_CritSect;
#else
# error "port me"
#endif


/**
 * Initializes the loader semaphore.
 *
 * @returns 0 on success, non-zero OS status code on failure.
 */
int     kldrHlpSemInit(void)
{
#ifdef __OS2__
    APIRET rc;
    g_hmtx = NULLHANDLE;
    rc = DosCreateMutexSem(NULL, &g_hmtx, 0, FALSE);
    if (rc)
        return rc;

#elif defined(__WIN__)
    InitializeCriticalSection(&g_CritSect);

#else
# error "port me"
#endif
    return 0;
}


/**
 * Terminates the loader semaphore.
 */
void    kldrHlpSemTerm(void)
{
#ifdef __OS2__
    HMTX hmtx = g_hmtx;
    g_hmtx = NULLHANDLE;
    DosCloseMutexSem(hmtx);

#elif defined(__WIN__)
    DeleteCriticalSection(&g_CritSect);

#else
# error "port me"
#endif
}


/**
 * Requests the loader sempahore ownership.
 * This can be done recursivly.
 *
 * @returns 0 on success, non-zero OS status code on failure.
 */
int     kldrHlpSemRequest(void)
{
#ifdef __OS2__
    APIRET rc = DosRequestMutexSem(g_hmtx, 5000);
    if (rc == ERROR_TIMEOUT || rc == ERROR_SEM_TIMEOUT || rc == ERROR_INTERRUPT)
    {
        unsigned i = 0;
        do
        {
            /** @todo check for deadlocks etc. */
            rc = DosRequestMutexSem(g_hmtx, 1000);
        } while (   (   rc == ERROR_TIMEOUT
                     || rc == ERROR_SEM_TIMEOUT
                     || rc == ERROR_INTERRUPT)
                 && i++ < 120);
    }
    return rc;

#elif defined(__WIN__)
    EnterCriticalSection(&g_CritSect);
    return 0;

#else
# error "port me"
#endif
}


/**
 * Releases the loader semaphore ownership.
 * The caller is responsible for making sure it's the semaphore owner!
 */
void    kldrHlpSemRelease(void)
{
#ifdef __OS2__
    APIRET rc = DosReleaseMutexSem(g_hmtx);
    kldrHlpAssert(!rc); (void)rc;

#elif defined(__WIN__)
    LeaveCriticalSection(&g_CritSect);

#else
# error "port me"
#endif

}