/* $Id: kLdrMod.c 2848 2006-11-02 00:08:16Z bird $ */
/** @file
 *
 * kLdr - The Dynamic Loader, The module interpreter.
 *
 * 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 "kLdrHlp.h"
#include "kLdrInternal.h"
#include "kLdrModMZ.h"
#if 1 /* testing headers */
# include "kLdrModPE.h"
# include "kLdrModLX.h"
# include "kLdrModELF32.h"
# include "kLdrModELF64.h"
#endif


/**
 * Open a executable image by file name.
 *
 * @returns 0 on success and *ppMod pointing to a module instance.
 *          On failure, a non-zero OS specific error code is returned.
 * @param   pszFilename     The filename to open.
 * @param   ppMod           Where to store the module handle.
 */
int kLdrModOpen(const char *pszFilename, PPKLDRMOD ppMod)
{
    /*
     * Open the file using a bit provider.
     */
    PKLDRRDR pRdr;
    int rc = kLdrRdrOpen(&pRdr, pszFilename);
    if (!rc)
    {
        rc = kLdrModOpenFromRdr(pRdr, ppMod);
        if (!rc)
            return 0;
       kLdrRdrClose(pRdr);
    }
    return rc;
}


/**
 * Open a executable image from a file provider instance.
 *
 * @returns 0 on success and *ppMod pointing to a module instance.
 *          On failure, a non-zero OS specific error code is returned.
 * @param   pRdr            The file provider instance to use.
 *                          On success, the ownership of the instance is taken by the
 *                          module and the caller must not ever touch it again.
 *                          (The instance is not closed on failure, the call has to do that.)
 * @param   ppMod           Where to store the module handle.
 */
int kLdrModOpenFromRdr(PKLDRRDR pRdr, PPKLDRMOD ppMod)
{
    union
    {
        uint32_t    u32;
        uint16_t    u16;
        uint16_t    au16[2];
        uint8_t     au8[4];
    }       u;
    off_t   offHdr = 0;
    int     rc;

    /*
     * Try figure out what kind of image this is.
     * Always read the 'new header' if we encounter MZ.
     */
    rc = kLdrRdrRead(pRdr, &u, sizeof(u), 0);
    if (rc)
        return rc;
    if (    u.u16 == IMAGE_DOS_SIGNATURE
        &&  kLdrRdrSize(pRdr) > sizeof(IMAGE_DOS_HEADER))
    {
        rc = kLdrRdrRead(pRdr, &u, sizeof(u.u32), KLDR_OFFSETOF(IMAGE_DOS_HEADER, e_lfanew));
        if (rc)
            return rc;
        if ((off_t)u.u32 < kLdrRdrSize(pRdr))
        {
            offHdr = u.u32;
            rc = kLdrRdrRead(pRdr, &u, sizeof(u.u32), offHdr);
            if (rc)
                return rc;
        }
        else
            u.u16 = IMAGE_DOS_SIGNATURE;
    }

    /*
     * Use the magic to select the appropriate image interpreter.
     */
    if (u.u16 == IMAGE_DOS_SIGNATURE)
        return KLDR_ERR_MZ_NOT_SUPPORTED;
    else if (u.u16 == IMAGE_NE_SIGNATURE)
        return KLDR_ERR_NE_NOT_SUPPORTED;
    else if (u.u16 == IMAGE_LX_SIGNATURE)
        return KLDR_ERR_LX_NOT_SUPPORTED;
    else if (u.u16 == IMAGE_LE_SIGNATURE)
        return KLDR_ERR_LE_NOT_SUPPORTED;
    else if (u.u32 == IMAGE_NT_SIGNATURE)
        return KLDR_ERR_PE_NOT_SUPPORTED;
    else if (u.u32 == IMAGE_ELF_SIGNATURE)
        return KLDR_ERR_ELF_NOT_SUPPORTED;
    return KLDR_ERR_UNKNOWN_FORMAT;
}


/**
 * Open a executable image using the native loader (if any).
 *
 * @returns 0 on success and *ppMod pointing to a module instance.
 *          On failure, a non-zero OS specific error code is returned.
 * @param   pszFilename     The filename to open.
 * @param   ppMod           Where to store the module handle.
 */
int kLdrModOpenNative(const char *pszFilename, PPKLDRMOD ppMod)
{
#ifdef __OS2__

    //DosLoadModule()
#elif defined(__WIN__)

#else
# error "Port me"
#endif
    return -1;
}



/**
 * Closes an open module.
 *
 * The caller is responsible for calling kLdrModUnmap() and kLdrFreeTLS()
 * before closing the module.
 *
 * @returns 0 on success,
 * @param   pMod    The module.
 */
int     kLdrModClose(PKLDRMOD pMod)
{
    //pMod->
    return -1;
}



/**
 * Queries a symbol by name or ordinal number.
 *
 * @returns 0 and *puValue and *pfKind on success.
 *          KLDR_ERR_SYMBOL_NOT_FOUND is returned if the symbol wasn't found.
 *          Other failures could stem from bad executable format failures,
 *          read failure in case pvBits isn't specified and no mapping should be used.
 * @param   pMod            The module.
 * @param   pvBits          Optional pointer to bits returned by kLdrModGetBits() currently located at BaseAddress.
 *                          This can be used by some module interpreters to reduce memory consumption.
 * @param   BaseAddress     The module base address to use when calculating the symbol value.
 *                          There are two special values that can be used:
 *                              KLDRMOD_BASEADDRESS_LINK and KLDRMOD_BASEADDRESS_MAP.
 * @param   uSymbol         The symbol ordinal. (optional)
 * @param   pszSymbol       The symbol name. (optional)
 * @param   puValue         Where to store the symbol value. (optional)
 * @param   pfKind          Where to store the symbol kind. (optional)
 */
int     kLdrModQuerySymbol(PKLDRMOD pMod, const void *pvBits, KLDRADDR BaseAddress, uint32_t uSymbol,
                           const char *pszSymbol, PKLDRADDR puValue, uint32_t *pfKind)
{
    return -1;
}


/**
 * Enumerate the symbols in the module.
 *
 * @returns 0 on success and non-zero a status code on failure.
 * @param   pMod            The module which symbols should be enumerated.
 * @param   fFlags          The enumeration flags. A combination of the KLDRMOD_ENUM_SYMS_FLAGS_* \#defines.
 * @param   pvBits          Optional pointer to bits returned by kLdrModGetBits() currently located at BaseAddress.
 *                          This can be used by some module interpreters to reduce memory consumption.
 * @param   BaseAddress     The module base address to use when calculating the symbol values.
 *                          There are two special values that could be can:
 *                              KLDRMOD_BASEADDRESS_LINK and KLDRMOD_BASEADDRESS_MAP.
 * @param   pfnCallback     The enumeration callback function.
 * @param   pvUser          The user argument to the callback function.
 */
int     kLdrModEnumSymbols(PKLDRMOD pMod, uint32_t fFlags, const void *pvBits, KLDRADDR BaseAddress,
                           PFNKLDRMODENUMSYMS pfnCallback, void *pvUser)
{
    return -1;
}


/**
 * Get the name of an import module by ordinal number.
 *
 * @returns 0 and name in pszName on success.
 *          On buffer overruns KLDR_ERR_BUFFER_OVERFLOW will be returned.
 *          On other failures and appropriate error code is returned.
 * @param   pMod            The module.
 * @param   pvBits          Optional pointer to bits returned by kLdrModGetBits().
 *                          This can be used by some module interpreters to reduce memory consumption.
 * @param   iImport         The import module ordinal number.
 * @param   pszName         Where to store the name.
 * @param   cchName         The size of the name buffer.
 */
int     kLdrModGetImport(PKLDRMOD pMod, void *pvBits, uint32_t iImport, const char *pszName, size_t cchName)
{
    return -1;
}


/**
 * Get the number of import modules.
 *
 * @returns The number of import modules. -1 if something really bad happens.
 * @param   pMod            The module.
 * @param   pvBits          Optional pointer to bits returned by kLdrModGetBits().
 *                          This can be used by some module interpreters to reduce memory consumption.
 */
int32_t kLdrModNumberOfImports(PKLDRMOD pMod, void *pvBits)
{
    return -1;
}


/**
 * Checks if this module can be executed by the specified arch+cpu.
 *
 * @returns 0 if it can, KLDR_ERR_ARCH_CPU_NOT_COMPATIBLE if it can't.
 *          Other failures may occur and cause other return values.
 * @param   pMod            The module.
 * @param   pvBits          Optional pointer to bits returned by kLdrModGetBits().
 *                          This can be used by some module interpreters to reduce memory consumption.
 */
int     kLdrModCanExecuteOn(PKLDRMOD pMod, void *pvBits, KLDRARCH enmArch, KLDRCPU enmCpu)
{
    //return KLDR_ERR_ARCH_CPU_NOT_COMPATIBLE;
    return 0;
}


/**
 * Gets the image stack info.
 *
 * @returns 0 on success, non-zero on failure.
 * @param   pMod
 * @param   pvBits          Optional pointer to bits returned by kLdrModGetBits() currently located at BaseAddress.
 *                          This can be used by some module interpreters to reduce memory consumption.
 * @param   BaseAddress     The module base address to use when calculating the stack address.
 *                          There are two special values that can be used:
 *                              KLDRMOD_BASEADDRESS_LINK and KLDRMOD_BASEADDRESS_MAP.
 * @param   pStackInfo      The stack information.
 */
int     kLdrModGetStackInfo(PKLDRMOD pMod, void *pvBits, KLDRADDR BaseAddress, PKLDRSTACKINFO pStackInfo)
{
    return -1;
}


/**
 * Queries the main entrypoint of the module.
 *
 * Only executable are supposed to have an main entrypoint, though some object and DLL
 * formats will also allow this.
 *
 * @returns 0 and *pMainEPAddress on success. Non-zero status code on failure.
 * @param   pMod            The module.
 * @param   pvBits          Optional pointer to bits returned by kLdrModGetBits() currently located at BaseAddress.
 *                          This can be used by some module interpreters to reduce memory consumption.
 * @param   BaseAddress     The module base address to use when calculating the entrypoint address.
 *                          There are two special values that can be used:
 *                              KLDRMOD_BASEADDRESS_LINK and KLDRMOD_BASEADDRESS_MAP.
 * @param   pMainEPAddress  Where to store the entry point address.
 */
int     kLdrModQueryMainEntrypoint(PKLDRMOD pMod, void *pvBits, KLDRADDR BaseAddress, PKLDRADDR pMainEPAddress)
{
    return 1;
}


/**
 * Get the size of the mapped module.
 *
 * @returns The size of the mapped module (in bytes).
 * @param   pMod            The module.
 */
size_t  kLdrModSize(PKLDRMOD pMod)
{
    return 0;
}


/**
 * Maps the module into the memory of the caller.
 *
 * On success the actual addresses for the segments can be found in MapAddress
 * member of each segment in the segment array.
 *
 * @returns 0 on success, non-zero OS or kLdr status code on failure.
 * @param   pMod            The module to be mapped.
 * @remark  kLdr only supports one mapping at a time of a module.
 */
int     kLdrModMap(PKLDRMOD pMod)
{
    return -1;
}


/**
 * Unmaps a module previously mapped by kLdrModMap().
 *
 * @returns 0 on success, non-zero OS or kLdr status code on failure.
 * @param   pMod            The module to unmap.
 */
int     kLdrModUnmap(PKLDRMOD pMod)
{
    return -1;
}


/**
 * Allocates Thread Local Storage for module mapped by kLdrModMap().
 *
 * Calling kLdrModAllocTLS() more than once without calling kLdrModFreeTLS()
 * between each invocation is not supported.
 *
 * @returns 0 on success, non-zero OS or kLdr status code on failure.
 * @param   pMod            The module.
 */
int     kLdrModAllocTLS(PKLDRMOD pMod)
{
    return 0;
}


/**
 * Frees Thread Local Storage previously allocated by kLdrModAllocTLS().
 *
 * The caller is responsible for only calling kLdrModFreeTLS() once
 * after calling kLdrModAllocTLS().
 *
 * @returns 0 on success, non-zero OS or kLdr status code on failure.
 * @param   pMod            The module.
 */
void    kLdrModFreeTLS(PKLDRMOD pMod)
{
}


/**
 * Reloads all dirty pages in a module previously mapped by kLdrModMap().
 *
 * The module interpreter may omit code pages if it can safely apply code
 * fixups again in a subsequent kLdrModFixupMapping() call.
 *
 * The caller is responsible for freeing TLS before calling this function.
 *
 * @returns 0 on success, non-zero OS or kLdr status code on failure.
 * @param   pMod            The module.
 */
int     kLdrModReload(PKLDRMOD pMod)
{
    return -1;
}


/**
 * Fixup the mapping made by kLdrModMap().
 *
 * The caller is only responsible for not calling this function more than
 * once without doing kLDrModReload() inbetween.
 *
 * @returns 0 on success, non-zero OS or kLdr status code on failure.
 * @param   pMod            The module.
 * @param   pfnGetImport    The callback for resolving external (imported) symbols.
 * @param   pvUser          The callback user argument.
 */
int     kLdrModFixupMapping(PKLDRMOD pMod, PFNKLDRMODGETIMPORT pfnGetImport, void *pvUser)
{
    return -1;
}


/**
 * Call the module initializiation function of a mapped module (if any).
 *
 * @returns 0 on success or no init function, non-zero on init function failure or invalid pMod.
 * @param   pMod            The module.
 */
int     kLdrModCallInit(PKLDRMOD pMod)
{
    return -1;
}


/**
 * Call the module termination function of a mapped module (if any).
 *
 * @returns 0 on success or no term function, non-zero on invalid pMod.
 * @param   pMod            The module.
 *
 * @remark  Termination function failure will be ignored by the module interpreter.
 */
int     kLdrModCallTerm(PKLDRMOD pMod)
{
    return 0;
}


/**
 * Call the thread attach or detach function of a mapped module (if any).
 *
 * @returns 0 on success or no attach/detach function, non-zero on attach failure or invalid pMod.
 * @param   pMod            The module.
 *
 * @remark  Detach function failure will be ignored by the module interpreter.
 */
int     kLdrModCallThread(PKLDRMOD pMod, unsigned fAttachingOrDetaching)
{
    return 0;
}


/**
 * Gets the module bits.
 *
 * The module interpreter will fill a mapping allocated by the caller with the
 * module bits reallocated to the specified address.
 *
 * @returns 0 on succes, non-zero OS or kLdr status code on failure.
 * @param   pMod            The module.
 * @param   pvBits          Where to put the bits.
 * @param   BaseAddress     The base address that should correspond to the first byte in pvBits
 *                          upon return.
 * @param   pfnGetImport    The callback ufor resolving external (imported) symbols.
 * @param   pvUser          The callback user argument.
 */
int     kLdrModGetBits(PKLDRMOD pMod, void *pvBits, KLDRADDR BaseAddress, PFNKLDRMODGETIMPORT pfnGetImport, void *pvUser)
{
    return -1;
}


/**
 * Relocates the module bits previously obtained by kLdrModGetBits().
 *
 * @returns 0 on succes, non-zero OS or kLdr status code on failure.
 * @param   pMod            The module.
 * @param   pvBits          Where to put the bits.
 * @param   NewBaseAddress  The new base address.
 * @param   OldBaseAddress  The old base address (i.e. the one specified to kLdrModGetBits() or as
 *                          NewBaseAddressto the previous kLdrModRelocateBits() call).
 * @param   pfnGetImport    The callback ufor resolving external (imported) symbols.
 * @param   pvUser          The callback user argument.
 */
int     kLdrModRelocateBits(PKLDRMOD pMod, void *pvBits, KLDRADDR NewBaseAddress, KLDRADDR OldBaseAddress,
                            PFNKLDRMODGETIMPORT pfnGetImport, void *pvUser)
{
    return -1;
}