/* $Id: kLdrRdr.c 2856 2006-11-04 22:19:33Z bird $ */
/** @file
 *
 * kLdr - The Dynamic Loader, file abstraction.
 *
 * 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                                                               *
*******************************************************************************/
#include <kLdr.h>
#include "kLdrInternal.h"


/*******************************************************************************
*   Defined Constants And Macros                                               *
*******************************************************************************/
/** @def KLDRRDR_STRICT
 * Define KLDRRDR_STRICT to enabled strict checks in KLDRMOD. */
#define KLDRRDR_STRICT 1

/** @def KLDRRDR_ASSERT
 * Assert that an expression is true when KLDR_STRICT is defined.
 */
#ifdef KLDRRDR_STRICT
# define KLDRRDR_ASSERT(expr)  kldrHlpAssert(expr)
#else
# define KLDRRDR_ASSERT(expr)  do {} while (0)
#endif

/** Return / crash validation of a reader argument. */
#define KLDRRDR_VALIDATE_EX(pRdr, rc) \
    do  { \
        if (    (pRdr)->u32Magic != KLDRRDR_MAGIC \
            ||  (pRdr)->pOps == NULL \
           )\
        { \
            return (rc); \
        } \
    } while (0)

/** Return / crash validation of a reader argument. */
#define KLDRRDR_VALIDATE(pRdr) \
    KLDRRDR_VALIDATE_EX(pRdr, KLDR_ERR_INVALID_PARAMETER)

/** Return / crash validation of a reader argument. */
#define KLDRRDR_VALIDATE_VOID(pRdr) \
    do  { \
        if (    (pRdr)->u32Magic != KLDRRDR_MAGIC \
            ||  (pRdr)->pOps == NULL \
           )\
        { \
            return; \
        } \
    } while (0)



/*******************************************************************************
*   Global Variables                                                           *
*******************************************************************************/
/** The list of file providers. */
static PCKLDRRDROPS g_pRdrHead = &g_kLdrRdrFileOps;


/**
 * Adds a new file provider.
 *
 * @param   pAdd        The new file provider.
 */
void kLdrRdrAddProvider(PKLDRRDROPS pAdd)
{
    pAdd->pNext = g_pRdrHead;
    g_pRdrHead = pAdd;
}


/**
 * Tries to opens a file.
 *
 * @returns 0 on success, OS status code on failure.
 * @param   ppRdr           Where to store the file provider instance.
 * @param   pszFilename     The filename.
 */
int kLdrRdrOpen(PPKLDRRDR ppRdr, const char *pszFilename)
{
    int             rc;
    PCKLDRRDROPS    pCur;
    for (pCur = g_pRdrHead; pCur; pCur = pCur->pNext)
    {
        rc = pCur->pfnCreate(ppRdr, pszFilename);
        if (!rc)
            return 0;
    }
    return rc;
}


/**
 * Closes the file.
 *
 * @returns 0 on success, OS specific error code on failure.
 *          On failure, the file provider instance will be in an indeterminate state - don't touch it!
 * @param   pRdr        The file provider instance.
 */
int kLdrRdrClose(PKLDRRDR pRdr)
{
    KLDRRDR_VALIDATE(pRdr);
    return pRdr->pOps->pfnDestroy(pRdr);
}


/** Read bits from the file.
 *
 * @returns 0 on success, OS specific error code on failure.
 * @param   pRdr        The file provider instance.
 * @param   pvBuf       Where to put the bits.
 * @param   cb          The number of bytes to read.
 * @param   off         Where to start reading.
 */
int kLdrRdrRead(PKLDRRDR pRdr, void *pvBuf, size_t cb, off_t off)
{
    KLDRRDR_VALIDATE(pRdr);
    return pRdr->pOps->pfnRead(pRdr, pvBuf, cb, off);
}


/** Map all the file bits into memory (read only).
 *
 * @returns 0 on success, OS specific error code on failure.
 * @param   pRdr        The file provider instance.
 * @param   ppvBits     Where to store the address of the mapping.
 *                      The size can be obtained using pfnSize.
 */
int kLdrRdrAllMap(PKLDRRDR pRdr, const void **ppvBits)
{
    KLDRRDR_VALIDATE(pRdr);
    return pRdr->pOps->pfnAllMap(pRdr, ppvBits);
}


/** Unmap a file bits mapping obtained by KLDRRDROPS::pfnAllMap.
 *
 * @returns 0 on success, OS specific error code on failure.
 * @param   pRdr        The file provider instance.
 * @param   pvBits      The mapping address.
 */
int kLdrRdrAllUnmap(PKLDRRDR pRdr, const void *pvBits)
{
    KLDRRDR_VALIDATE(pRdr);
    return pRdr->pOps->pfnAllUnmap(pRdr, pvBits);
}


/** Get the file size.
 *
 * @returns The file size. Returns -1 on failure.
 * @param   pRdr        The file provider instance.
 */
off_t kLdrRdrSize(PKLDRRDR pRdr)
{
    KLDRRDR_VALIDATE(pRdr);
    return pRdr->pOps->pfnSize(pRdr);
}


/** Get the file pointer offset.
 *
 * @returns The file pointer offset. Returns -1 on failure.
 * @param   pRdr        The file provider instance.
 */
off_t kLdrRdrTell(PKLDRRDR pRdr)
{
    KLDRRDR_VALIDATE(pRdr);
    return pRdr->pOps->pfnTell(pRdr);
}


/** Get the file name.
 *
 * @returns The file name. Returns NULL on failure.
 * @param   pRdr        The file provider instance.
 */
const char *kLdrRdrName(PKLDRRDR pRdr)
{
    KLDRRDR_VALIDATE_EX(pRdr, NULL);
    return pRdr->pOps->pfnName(pRdr);
}


/**
 * Gets the page size used when mapping sections of the file.
 *
 * @returns The page size.
 * @param   pRdr        The file provider instance.
 */
size_t  kLdrRdrPageSize(PKLDRRDR pRdr)
{
    KLDRRDR_VALIDATE_EX(pRdr, 0x10000);
    return pRdr->pOps->pfnPageSize(pRdr);
}


/**
 * Prepares a memory region to map file sections into.
 *
 * @returns 0 on success, OS specific error code on failure.
 * @param   pRdr        The file provider instance.
 * @param   ppv         If fFixed is set, *ppv contains the memory location which
 *                      the region should be based at. If fFixed is clear the OS
 *                      is free to choose the location.
 *                      On successful return *ppv contains address of the prepared
 *                      memory region.
 * @param   cb          The size of the memory region to prepare.
 * @param   fFixed      When set *ppv will contain the desired region address.
 *
 */
int kLdrRdrPrepare(PKLDRRDR pRdr, void **ppv, size_t cb, unsigned fFixed)
{
    KLDRRDR_VALIDATE(pRdr);
    return pRdr->pOps->pfnPrepare(pRdr, ppv, cb, fFixed);
}


/**
 * Maps a section of the file into the memory region reserved by pfnPrepare.
 *
 * @returns 0 on success, OS specific error code on failure.
 * @param   pRdr        The file provider instance.
 * @param   pv          The address in the prepared region.
 * @param   cb          The size of the memory mapping.
 * @param   enmProt     The desired memory protection.
 * @param   offFile     The start of the raw file bytes.
 * @param   cbFile      The number of raw file bytes. This must be less or equal to cb.
 */
int kLdrRdrMap(PKLDRRDR pRdr, void *pv, size_t cb, KLDRPROT enmProt, off_t offFile, size_t cbFile)
{
    KLDRRDR_VALIDATE(pRdr);
    return pRdr->pOps->pfnMap(pRdr, pv, cb, enmProt, offFile, cbFile);
}


/**
 * Reloads dirty pages in mapped section.
 *
 * @returns 0 on success, OS specific error code on failure.
 * @param   pRdr        The file provider instance.
 * @param   pv          The address in the prepared region.
 * @param   cb          The size of the memory mapping.
 * @param   enmProt     The desired memory protection.
 * @param   offFile     The start of the raw file bytes.
 * @param   cbFile      The number of raw file bytes. This must be less or equal to cb.
 */
int kLdrRdrRefreshMap(PKLDRRDR pRdr, void *pv, size_t cb, KLDRPROT enmProt, off_t offFile, size_t cbFile)
{
    KLDRRDR_VALIDATE(pRdr);
    return pRdr->pOps->pfnRefreshMap(pRdr, pv, cb, enmProt, offFile, cbFile);
}


/**
 * Changes the page protection of a section mapped using pfnMap.
 *
 * This is typically used for applying fixups and similar.
 *
 * @returns 0 on success, OS specific error code on failure.
 * @param   pRdr        The file provider instance.
 * @param   pv          The address passed to pfnMap.
 * @param   cb          The size passed to pfnMap.
 * @param   enmProt     The desired memory protection.
 */
int kLdrRdrProtect(PKLDRRDR pRdr, void *pv, size_t cb, KLDRPROT enmProt)
{
    KLDRRDR_VALIDATE(pRdr);
    return pRdr->pOps->pfnProtect(pRdr, pv, cb, enmProt);
}


/**
 * Unmaps a section of the file previously mapped using pfnMap.
 *
 * @returns 0 on success, OS specific error code on failure.
 * @param   pRdr        The file provider instance.
 * @param   pv          The address passed to pfnMap.
 * @param   cb          The size passed to pfnMap.
 */
int kLdrRdrUnmap(PKLDRRDR pRdr, void *pv, size_t cb)
{
    KLDRRDR_VALIDATE(pRdr);
    return pRdr->pOps->pfnUnmap(pRdr, pv, cb);
}


/**
 * Releases the memory region prepared by pfnPrepare().
 *
 * Before calling this function, all sections mapped by pfnMap must first be unmapped by calling pfnUnmap.
 *
 * @returns 0 on success, OS specific error code on failure.
 * @param   pRdr        The file provider instance.
 * @param   pv          The address of the prepared region.
 * @param   cb          The size of the prepared region.
 */
int kLdrRdrUnprepare(PKLDRRDR pRdr, void *pv, size_t cb)
{
    KLDRRDR_VALIDATE(pRdr);
    return pRdr->pOps->pfnUnprepare(pRdr, pv, cb);
}


/**
 * We're done reading from the file but would like to keep file mappings.
 *
 * If the OS support closing the file handle while the file is mapped,
 * the reader should do so.
 *
 * @param   pRdr        The file provider instance.
 */
void kLdrRdrDone(PKLDRRDR pRdr)
{
    KLDRRDR_VALIDATE_VOID(pRdr);
    pRdr->pOps->pfnDone(pRdr);
}