/* $Id: $ */
/** @file
 *
 * kLdr - The Dynamic Loader.
 *
 * Copyright (c) 2006 knut st. osmundsen <bird@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
 *
 */

#include "kLdr.h"

/** memcpy */
#define kLdrMemCopy(a,b,c) __builtin_memcpy(a,b,c)
/** Get the minimum of two values. */
#define KLDR_MIN(a, b) ((a) <= (b) ? (a) : (b))


/*******************************************************************************
*   Global Variables                                                           *
*******************************************************************************/
/** Pointer to the head module (the executable).
 * (This is exported, so no prefix.) */
PKLDRMOD        kLdrModuleHead = NULL;
/** Pointer to the tail module.
 * (This is exported, so no prefix.) */
PKLDRMOD        kLdrModuleTail = NULL;
/** The Library search path. */
char            kLdrLibraryPath[4096];
/** The executable flags. */
uint32_t        kLdrFlags;
/** Bootstrap stack and temporary space. */
char            abStack[8192];
/** Set if we've initialized the loader. */
int             fInitialized = 0;


/*******************************************************************************
*   Internal Functions                                                         *
*******************************************************************************/
static int kldrInit(void);
static int kldrTerm(void);


/**
 * Initialize the loader.
 */
int kldrInit(void)
{
    if (fInitialized)
        return 0;
    /** @todo */
    return 0;
}



void kldrLoadExe(PKLDREXEARGS pArgs)
{
    /*
     * Copy the arguments into the globals and do load init.
     */
    kLdrFlags = pArgs->fFlags;
    kLdrMemCopy(kLdrLibraryPath, pArgs->szLibPath, KLDR_MIN(sizeof(pArgs->szLibPath), sizeof(kLdrLibraryPath)));
    int rc = kldrInit();
    if (rc)
        kldrFailure(rc, "kLdr: Init failure, rc=%d\n", rc);

    /*
     * Open the executable module.
     */
    PKLDRMOD pExe;
    kldrOpenExe(pArgs->szExecutable, &pExe);

    /* Map the segments. */
    kldrModMapSegments(pExe);

    /*
     * This is the point where we switch to the executable
     * stack, allocating it if necessary.
     */
    void *pvBottom;
    kldrModSetupStack(pExe, &pvBottom);
    kldrLoadExecSwitchStack(pvBottom);
}


void kldrLoadExeOnNewStack(void)
{
    /*
     * Load all dependant modules.
     */
    PKLDRMOD pCur;
    do  for (pCur = kLdrModuleHead; pCur; pCur = pCur->pNext)
        {
            if (pCur->enmState >= KLDRSTATE_DEPS)
                continue;
            kldrModLoadDeps(pCur);
        }
    while (pCur);

    /*
     * Do fixups (FIFO).
     */
    for (pCur = kLdrModuleHead; pCur; pCur = pCur->pNext)
    {
        if (pCur->enmState >= KLDRSTATE_FIXED)
            continue;
        kldrModFixup(pCur, 0);
    }

    /*
     * Do module initialization.
     */
    for (pCur = kLdrModuleTail; pCur != kLdrModuleTail; pCur = pCur->pPrev)
    {
        if (pCur->enmState >= KLDRSTATE_INITED)
            continue;
        kldrModCallInit(pCur);
    }

    /*
     * Get the executable start address and commit the work that's been done.
     */
    void *pvEntry;
    kldrModGetExeEntry(&pvEntry);

    for (pCur = kLdrModuleHead; pCur; pCur = pCur->pNext)
        if (pCur->enmState == KLDRSTATE_INITED)
            pCur->enmState = KLDRSTATE_LOADED;

    kldrSemRelease();

    /*
     * We're now ready for starting the executable code.
     */
    kldrOSStartExe(pLdrModuleHead, pvEntry);
}


int kLdrLoadDll(const char *pszFilename, unsigned fFlags, void *pvmod)
{

    return -1;
}




/**
 * Panic / failure
 *
 * @returns rc if we're in a position where we can return.
 * @param   rc              Return code.
 * @param   pszFormat       Message string. Limited fprintf like formatted.
 * @param   ...             Message string arguments.
 */
int kldrFailure(int rc, const char *pszFormat, ...)
{
    kldrExit(1);
    return rc;
}