/* $Id: kLdrRdrFile.c 2974 2007-02-14 10:12:44Z 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                                                               *
*******************************************************************************/
#ifdef __OS2__
# define INCL_ERRORS
# define INCL_BASE
# include <os2.h>

#elif defined(__WIN32__) || defined(__WIN64__) || defined(__WIN__)
# define WIN32_NO_STATUS
# include <Windows.h>
# ifndef __WIN__
#  define __WIN__
# endif
# include <ntsecapi.h>
# include <ntstatus.h>

  /** @todo find a non-conflicting header with NTSTATUS, NTAPI, ++ */
  typedef LONG NTSTATUS;
  #define NT_SUCCESS(x) ((x)>=0)

  typedef struct _OBJECT_ATTRIBUTES
  {
      ULONG   Length;
      HANDLE  RootDirectory;
      PUNICODE_STRING ObjectName;
      ULONG   Attributes;
      PVOID   SecurityDescriptor;
      PVOID   SecurityQualityOfService;
  } OBJECT_ATTRIBUTES, *POBJECT_ATTRIBUTES;

  typedef enum _SECTION_INHERIT
  {
      ViewShare = 1,
      ViewUnmap = 2
  } SECTION_INHERIT;

# define NTOSAPI __declspec(dllimport)
# define NtCurrentProcess() GetCurrentProcess()

# ifndef MEM_DOS_LIM
#  define MEM_DOS_LIM 0x40000000UL
# endif

  NTOSAPI
  NTSTATUS
  NTAPI
  NtCreateSection(
      OUT PHANDLE SectionHandle,
      IN ACCESS_MASK DesiredAccess,
      IN POBJECT_ATTRIBUTES ObjectAttributes OPTIONAL,
      IN PLARGE_INTEGER SectionSize OPTIONAL,
      IN ULONG Protect,
      IN ULONG Attributes,
      IN HANDLE FileHandle OPTIONAL
  );

  NTOSAPI
  NTSTATUS
  NTAPI
  NtMapViewOfSection(
      IN HANDLE SectionHandle,
      IN HANDLE ProcessHandle,
      IN OUT PVOID *BaseAddress,
      IN ULONG ZeroBits,
      IN ULONG CommitSize,
      IN OUT PLARGE_INTEGER SectionOffset OPTIONAL,
      IN OUT PSIZE_T ViewSize,
      IN SECTION_INHERIT InheritDisposition,
      IN ULONG AllocationType,
      IN ULONG Protect
  );

  NTOSAPI
  NTSTATUS
  NTAPI
  NtUnmapViewOfSection(
      IN HANDLE ProcessHandle,
      IN PVOID BaseAddress
  );

  NTOSAPI
  NTSTATUS
  NTAPI
  NtClose(
      IN HANDLE Handle
  );

  NTOSAPI
  NTSTATUS
  NTAPI
  ZwProtectVirtualMemory(
      IN HANDLE ProcessHandle,
      IN OUT PVOID *BaseAddress,
      IN OUT PULONG ProtectSize,
      IN ULONG NewProtect,
      OUT PULONG OldProtect
  );
# define NtProtectVirtualMemory ZwProtectVirtualMemory

  NTOSAPI
  NTSTATUS
  NTAPI
  NtAllocateVirtualMemory(
      IN HANDLE ProcessHandle,
      IN OUT PVOID *BaseAddress,
      IN ULONG ZeroBits,
      IN OUT PULONG AllocationSize,
      IN ULONG AllocationType,
      IN ULONG Protect
  );

  NTOSAPI
  NTSTATUS
  NTAPI
  NtFreeVirtualMemory(
      IN HANDLE ProcessHandle,
      IN OUT PVOID *BaseAddress,
      IN OUT PULONG FreeSize,
      IN ULONG FreeType
  );

#else
# error "port me"
#endif

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


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

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


/*******************************************************************************
*   Structures and Typedefs                                                    *
*******************************************************************************/
/**
 * Prepared stuff.
 */
typedef struct KLDRRDRFILEPREP
{
    /** The address of the prepared region. */
    void           *pv;
    /** The size of the prepared region. */
    size_t          cb;
#if defined(__WIN__) || defined(__NT__)
    /** Handle to the section created to map the file. */
    HANDLE          hSection;
#endif
} KLDRRDRFILEPREP, *PKLDRRDRFILEPREP;

/**
 * The file provier instance for native files.
 */
typedef struct KLDRRDRFILE
{
    /** The file reader vtable. */
    KLDRRDR             Core;
    /** The file handle. */
#ifdef __OS2__
    HFILE               File;
#elif defined(__WIN__) || defined(__NT__)
    HANDLE              File;
#else
# error "Port me!"
#endif
    /** The current file offset. */
    KLDRFOFF            off;
    /** The file size. */
    KLDRFOFF            cb;
    /** Array where we stuff the mapping area data. */
    KLDRRDRFILEPREP     aPreps[4];
    /** The number of current preps. */
    uint32_t            cPreps;
    /** Number of mapping references. */
    int32_t             cMappings;
    /** The memory mapping. */
    void               *pvMapping;
    /** The filename. */
    char                szFilename[1];
} KLDRRDRFILE, *PKLDRRDRFILE;


/*******************************************************************************
*   Internal Functions                                                         *
*******************************************************************************/
static void     kldrRdrFileDone(PKLDRRDR pRdr);
static int      kldrRdrFileUnmap(PKLDRRDR pRdr, void *pvBase, uint32_t cSegments, PCKLDRSEG paSegments);
static int      kldrRdrFileGenericUnmap(PKLDRRDR pRdr, PKLDRRDRFILEPREP pPrep, uint32_t cSegments, PCKLDRSEG paSegments);
static int      kldrRdrFileProtect(PKLDRRDR pRdr, void *pvBase, uint32_t cSegments, PCKLDRSEG paSegments, unsigned fUnprotectOrProtect);
static int      kldrRdrFileGenericProtect(PKLDRRDR pRdr, PKLDRRDRFILEPREP pPrep, uint32_t cSegments, PCKLDRSEG paSegments, unsigned fUnprotectOrProtect);
static int      kldrRdrFileRefresh(PKLDRRDR pRdr, void *pvBase, uint32_t cSegments, PCKLDRSEG paSegments);
static int      kldrRdrFileGenericRefresh(PKLDRRDR pRdr, PKLDRRDRFILEPREP pPrep, uint32_t cSegments, PCKLDRSEG paSegments);
static int      kldrRdrFileMap(PKLDRRDR pRdr, void **ppvBase, uint32_t cSegments, PCKLDRSEG paSegments, unsigned fFixed);
static int      kldrRdrFileGenericMap(PKLDRRDR pRdr, PKLDRRDRFILEPREP pPrep, uint32_t cSegments, PCKLDRSEG paSegments, unsigned fFixed);
static size_t   kldrRdrFilePageSize(PKLDRRDR pRdr);
static const char *kldrRdrFileName(PKLDRRDR pRdr);
static KLDRFOFF kldrRdrFileTell(PKLDRRDR pRdr);
static KLDRFOFF kldrRdrFileSize(PKLDRRDR pRdr);
static int      kldrRdrFileAllUnmap(PKLDRRDR pRdr, const void *pvBits);
static int      kldrRdrFileAllMap(PKLDRRDR pRdr, const void **ppvBits);
static int      kldrRdrFileRead(PKLDRRDR pRdr, void *pvBuf, size_t cb, KLDRFOFF off);
static int      kldrRdrFileDestroy(PKLDRRDR pRdr);
static int      kldrRdrFileCreate(PPKLDRRDR ppRdr, const char *pszFilename);


/*******************************************************************************
*   Global Variables                                                           *
*******************************************************************************/
/** Native file provider operations. */
const KLDRRDROPS g_kLdrRdrFileOps =
{
    "native file",
    NULL,
    kldrRdrFileCreate,
    kldrRdrFileDestroy,
    kldrRdrFileRead,
    kldrRdrFileAllMap,
    kldrRdrFileAllUnmap,
    kldrRdrFileSize,
    kldrRdrFileTell,
    kldrRdrFileName,
    kldrRdrFilePageSize,
    kldrRdrFileMap,
    kldrRdrFileRefresh,
    kldrRdrFileProtect,
    kldrRdrFileUnmap,
    kldrRdrFileDone,
    42
};


#if defined(__WIN__) || defined(__NT__)
/**
 * Converts a kLdr segment protection to NT protection for a mapping.
 *
 * @returns Nt page protection.
 * @param   enmProt     kLdr protection.
 */
static ULONG kldrRdrFileGetNtMapProt(KLDRPROT enmProt)
{
    switch (enmProt)
    {
        case KLDRPROT_NOACCESS:             return PAGE_NOACCESS;
        case KLDRPROT_READONLY:             return PAGE_READONLY;
        case KLDRPROT_READWRITE:            return PAGE_READWRITE;
        case KLDRPROT_WRITECOPY:            return PAGE_WRITECOPY;
        case KLDRPROT_EXECUTE:              return PAGE_EXECUTE;
        case KLDRPROT_EXECUTE_READ:         return PAGE_EXECUTE_READ;
        case KLDRPROT_EXECUTE_READWRITE:    return PAGE_EXECUTE_READWRITE;
        case KLDRPROT_EXECUTE_WRITECOPY:    return PAGE_EXECUTE_WRITECOPY;
        default:                            return ~(ULONG)0;
    }
}


/**
 * Converts a kLdr segment protection to NT protection for a allocation.
 *
 * @returns Nt page protection.
 * @param   enmProt     kLdr protection.
 */
static ULONG kldrRdrFileGetNtAllocProt(KLDRPROT enmProt)
{
    switch (enmProt)
    {
        case KLDRPROT_NOACCESS:             return PAGE_NOACCESS;
        case KLDRPROT_READONLY:             return PAGE_READONLY;
        case KLDRPROT_WRITECOPY:
        case KLDRPROT_READWRITE:            return PAGE_READWRITE;
        case KLDRPROT_EXECUTE:              return PAGE_EXECUTE;
        case KLDRPROT_EXECUTE_READ:         return PAGE_EXECUTE_READ;
        case KLDRPROT_EXECUTE_WRITECOPY:
        case KLDRPROT_EXECUTE_READWRITE:    return PAGE_EXECUTE_READWRITE;
        default:                            return ~(ULONG)0;
    }
}
#endif


/** @copydoc KLDRRDR::pfnDone */
static void     kldrRdrFileDone(PKLDRRDR pRdr)
{
}


/**
 * Finds a prepared mapping region.
 *
 * @returns Pointer to the aPrep entry.
 * @param   pFile   The instance data.
 * @param   pv      The base of the region.
 */
static PKLDRRDRFILEPREP kldrRdrFileFindPrepExact(PKLDRRDRFILE pFile, void *pv)
{
    int32_t i = pFile->cPreps;
    while (i-- > 0)
        if (pFile->aPreps[i].pv == pv)
            return &pFile->aPreps[i];
    return NULL;
}


/** @copydoc KLDRRDR::pfnUnmap */
static int      kldrRdrFileUnmap(PKLDRRDR pRdr, void *pvBase, uint32_t cSegments, PCKLDRSEG paSegments)
{
    PKLDRRDRFILE        pRdrFile = (PKLDRRDRFILE)pRdr;
    PKLDRRDRFILEPREP    pPrep = kldrRdrFileFindPrepExact(pRdrFile, pvBase);
    int                 rc;
    if (!pPrep)
        return KLDR_ERR_INVALID_PARAMETER;

#if defined(__WIN__) || defined(__NT__)
    if (pPrep->hSection != NULL)
    {
        /** @todo implement me. */
        return -1;
    }
#endif

    rc = kldrRdrFileGenericUnmap(pRdr, pPrep, cSegments, paSegments);

    /* remove the mapping data on success. */
    if (!rc)
    {
        pRdrFile->cPreps--;
        if (pPrep != &pRdrFile->aPreps[pRdrFile->cPreps])
            *pPrep = pRdrFile->aPreps[pRdrFile->cPreps];
    }
    return rc;
}


/** Generic implementation of kldrRdrFileUnmap. */
static int kldrRdrFileGenericUnmap(PKLDRRDR pRdr, PKLDRRDRFILEPREP pPrep, uint32_t cSegments, PCKLDRSEG paSegments)
{
    kldrRdrFileGenericProtect(pRdr, pPrep, cSegments, paSegments, 1 /* unprotect */);
    return kldrHlpPageFree(pPrep->pv, pPrep->cb);
}


/** @copydoc KLDRRDR::pfnProtect */
static int      kldrRdrFileProtect(PKLDRRDR pRdr, void *pvBase, uint32_t cSegments, PCKLDRSEG paSegments, unsigned fUnprotectOrProtect)
{
    PKLDRRDRFILE        pRdrFile = (PKLDRRDRFILE)pRdr;
    PKLDRRDRFILEPREP    pPrep = kldrRdrFileFindPrepExact(pRdrFile, pvBase);
    if (!pPrep)
        return KLDR_ERR_INVALID_PARAMETER;

#if defined(__WIN__) || defined(__NT__)
    if (pPrep->hSection != NULL)
    {
        /** @todo implement me. */
        return -1;
    }
#endif

    return kldrRdrFileGenericProtect(pRdr, pPrep, cSegments, paSegments, fUnprotectOrProtect);
}


/** Generic implementation of kldrRdrFileProtect. */
static int kldrRdrFileGenericProtect(PKLDRRDR pRdr, PKLDRRDRFILEPREP pPrep, uint32_t cSegments, PCKLDRSEG paSegments, unsigned fUnprotectOrProtect)
{
    uint32_t i;

    /*
     * Iterate the segments and apply memory protection changes.
     */
    for (i = 0; i < cSegments; i++)
    {
        int rc;
        void *pv;
        KLDRPROT enmProt;

        if (paSegments[i].RVA == NIL_KLDRADDR)
            continue;

        /* calc new protection. */
        enmProt = paSegments[i].enmProt;
        if (fUnprotectOrProtect)
        {
            switch (enmProt)
            {
                case KLDRPROT_NOACCESS:
                case KLDRPROT_READONLY:
                case KLDRPROT_READWRITE:
                case KLDRPROT_WRITECOPY:
                    enmProt = KLDRPROT_READWRITE;
                    break;
                case KLDRPROT_EXECUTE:
                case KLDRPROT_EXECUTE_READ:
                case KLDRPROT_EXECUTE_READWRITE:
                case KLDRPROT_EXECUTE_WRITECOPY:
                    enmProt = KLDRPROT_EXECUTE_READWRITE;
                    break;
                default:
                    KLDRRDRFILE_ASSERT(!"bad enmProt");
                    return -1;
            }
        }
        else
        {
            /* copy on write -> normal write. */
            if (enmProt == KLDRPROT_EXECUTE_WRITECOPY)
                enmProt = KLDRPROT_EXECUTE_READWRITE;
            else if (enmProt == KLDRPROT_WRITECOPY)
                enmProt = KLDRPROT_READWRITE;
        }

        pv = (uint8_t *)pPrep->pv + paSegments[i].RVA;

        rc = kldrHlpPageProtect(pv, paSegments[i].cbMapped, enmProt);
        if (rc)
            break;
    }

    return 0;
}


/** @copydoc KLDRRDR::pfnRefresh */
static int      kldrRdrFileRefresh(PKLDRRDR pRdr, void *pvBase, uint32_t cSegments, PCKLDRSEG paSegments)
{
    PKLDRRDRFILE        pRdrFile = (PKLDRRDRFILE)pRdr;
    PKLDRRDRFILEPREP    pPrep = kldrRdrFileFindPrepExact(pRdrFile, pvBase);
    if (!pPrep)
        return KLDR_ERR_INVALID_PARAMETER;

#if defined(__WIN__) || defined(__NT__)
    if (pPrep->hSection != NULL)
    {
        /** @todo implement me. */
        return -1;
    }
#endif

    return kldrRdrFileGenericRefresh(pRdr, pPrep, cSegments, paSegments);
}


/** Generic implementation of kldrRdrFileRefresh. */
static int      kldrRdrFileGenericRefresh(PKLDRRDR pRdr, PKLDRRDRFILEPREP pPrep, uint32_t cSegments, PCKLDRSEG paSegments)
{
    int rc;
    int rc2;
    uint32_t i;

    /*
     * Make everything writable again.
     */
    rc = kldrRdrFileGenericProtect(pRdr, pPrep, cSegments, paSegments, 1 /* unprotect */);
    if (rc)
    {
        kldrRdrFileGenericProtect(pRdr, pPrep, cSegments, paSegments, 0 /* protect */);
        return rc;
    }

    /*
     * Clear everything.
     */
    /** @todo only zero the areas not covered by raw file bits. */
    kLdrHlpMemSet(pPrep->pv, 0, pPrep->cb);

    /*
     * Reload all the segments.
     * We could possibly skip some segments, but we currently have
     * no generic way of figuring out which at the moment.
     */
    for (i = 0; i < cSegments; i++)
    {
        void *pv;

        if (    paSegments[i].RVA == NIL_KLDRADDR
            ||  paSegments[i].cbFile <= 0)
            continue;

        pv = (uint8_t *)pPrep->pv + paSegments[i].RVA;
        rc = pRdr->pOps->pfnRead(pRdr, pv, paSegments[i].cbFile, paSegments[i].offFile);
        if (rc)
            break;
    }

    /*
     * Protect the bits again.
     */
    rc2 = kldrRdrFileGenericProtect(pRdr, pPrep, cSegments, paSegments, 0 /* protect */);
    if (rc2 && rc)
        rc = rc2;

    return rc;
}


/** @copydoc KLDRRDR::pfnMap */
static int      kldrRdrFileMap(PKLDRRDR pRdr, void **ppvBase, uint32_t cSegments, PCKLDRSEG paSegments, unsigned fFixed)
{
    PKLDRRDRFILE        pRdrFile = (PKLDRRDRFILE)pRdr;
    PKLDRRDRFILEPREP    pPrep = &pRdrFile->aPreps[pRdrFile->cPreps];
    KLDRSIZE            cbTotal;
    const size_t        cbPage = pRdr->pOps->pfnPageSize(pRdr);
    int                 rc;
    uint32_t            i;

    if (pRdrFile->cPreps >= KLDR_ELEMENTS(pRdrFile->aPreps))
        return KLDR_ERR_TOO_MANY_MAPPINGS;

    /*
     * Calc the total mapping space needed.
     */
    cbTotal = 0;
    for (i = 0; i < cSegments; i++)
    {
        KLDRSIZE uRVASegmentEnd;
        if (paSegments[i].RVA == NIL_KLDRADDR)
            continue;
        uRVASegmentEnd = paSegments[i].RVA + paSegments[i].cbMapped;
        if (cbTotal < uRVASegmentEnd)
            cbTotal = uRVASegmentEnd;
    }
    pPrep->cb = (size_t)cbTotal;
    if (pPrep->cb != cbTotal)
        return KLDR_ERR_ADDRESS_OVERFLOW;
    pPrep->cb = (pPrep->cb + (cbPage - 1)) & ~(cbPage- 1);

#if defined(__WIN__) || defined(__NT__)
    /*
     * The NT memory mapped file API sucks in a lot of ways. Unless you're actually
     * trying to map a PE image and the kernel can parse the file for it self, the
     * API just isn't up to scratch.
     *
     * Problems:
     *      1. Reserving memory for the views is risky because you can't reserve and
     *         map into the reserved space. So, other threads might grab the memory
     *         before we get to it.
     *      2. The page aligning of file offsets makes it impossible to map most
     *         executable images since these are commonly sector aligned.
     *      3. When mapping a read+execute file, its not possible to create section
     *         larger than the file since the section size is bound to the data file
     *         size. This wouldn't have been such a problem if it was possible to
     *         map views beyond the section restriction, i.e. have a file size and
     *         view size.
     *      4. Only x86 can map views at page granularity it seems, and that only
     *         using an undocument flag. The default granularity is 64KB.
     *      5. There is more crappyness here...
     *
     * So, first we'll have to check if we can the file using the crappy NT APIs.
     * Chances are we can't.
     */
    for (i = 0; i < cSegments; i++)
    {
        if (paSegments[i].RVA == NIL_KLDRADDR)
            continue;

        /* The file backing of the segments must be page aligned. */
        if (    paSegments[i].cbFile > 0
            &&  paSegments[i].offFile & (cbPage - 1))
            break;

        /* Only page alignment gaps between the file size and the mapping size. */
        if (    paSegments[i].cbFile > 0
            &&  (paSegments[i].cbFile & ~(cbPage - 1)) != (paSegments[i].cbMapped & ~(cbPage - 1)) )
            break;

        /* The mapping addresses of the segments must be page aligned.
         * Non-x86 will probably require 64KB alignment here. */
        if (paSegments[i].RVA & (cbPage - 1))
            break;

        /* If we do have to allocate the segment it's RVA must be 64KB aligned. */
        if (    paSegments[i].cbFile > 0
            &&  (paSegments[i].RVA & 0xffff))
            break;
    }
    /** @todo if this is a PE image, we might just try a SEC_IMAGE mapping. It'll work if the host and image machines matches. */
    if (i == cSegments)
    {
        /* WOW! it may work out! Incredible! */
        SIZE_T          ViewSize;
        LARGE_INTEGER   SectionOffset;
        LARGE_INTEGER   MaxiumSize;
        NTSTATUS        Status;
        PVOID           pv;

        MaxiumSize.QuadPart = pRdr->pOps->pfnSize(pRdr);
        if (MaxiumSize.QuadPart > (LONGLONG)cbTotal)
            MaxiumSize.QuadPart = cbTotal;

        Status = NtCreateSection(&pPrep->hSection,
                                 SECTION_MAP_EXECUTE | SECTION_MAP_READ,    /* desired access */
                                 NULL,                                      /* object attributes */
                                 &MaxiumSize,
                                 PAGE_EXECUTE_WRITECOPY,                    /* page attributes */
                                 SEC_COMMIT,                                /* section attributes */
                                 pRdrFile->File);
        if (!NT_SUCCESS(Status))
            return (int)Status;

        /*
         * Determin the base address.
         */
        if (fFixed)
            pPrep->pv = *ppvBase;
        else
        {
            pv = NULL;
            ViewSize = (size_t)cbTotal;

            Status = NtAllocateVirtualMemory(NtCurrentProcess(),
                                             &pv,
                                             0,                             /* ZeroBits */
                                             &ViewSize,
                                             MEM_RESERVE,
                                             PAGE_READONLY);
            if (NT_SUCCESS(Status))
            {
                pPrep->pv = *ppvBase = pv;
                ViewSize = 0;
                Status = NtFreeVirtualMemory(NtCurrentProcess(), &pv, &ViewSize, MEM_RELEASE);
            }
            if (!NT_SUCCESS(Status))
            {
                NtClose(pPrep->hSection);
                return Status;
            }
        }

        /*
         * Map the segments.
         */
        for (i = 0; i < cSegments; i++)
        {
            ULONG fPageProt;

            if (paSegments[i].RVA == NIL_KLDRADDR)
                continue;

            pv = (uint8_t *)pPrep->pv + paSegments[i].RVA;
            if (paSegments[i].cbFile > 0)
            {
                SectionOffset.QuadPart = paSegments[i].offFile;
                ViewSize = paSegments[i].cbFile;
                fPageProt = kldrRdrFileGetNtMapProt(paSegments[i].enmProt);
                /* STATUS_MAPPED_ALIGNMENT
                   STATUS_CONFLICTING_ADDRESSES
                   STATUS_INVALID_VIEW_SIZE */
                Status = NtMapViewOfSection(pPrep->hSection, NtCurrentProcess(),
                                            &pv,
                                            0,                                  /* ZeroBits */
                                            0,                                  /* CommitSize */
                                            &SectionOffset,                     /* SectionOffset */
                                            &ViewSize,
                                            ViewUnmap,
                                            MEM_DOS_LIM,                        /* AllocationType */
                                            fPageProt);
                /* do we have to zero anything? */
                if (    NT_SUCCESS(Status)
                    &&  0/*later*/)
                {
                    /*ULONG OldPageProt = 0;
                      NtProtectVirtualMemory(NtCurrentProcess(), &pv, &ViewSize, , */
                }
            }
            else
            {
                ViewSize = paSegments[i].cbMapped;
                fPageProt = kldrRdrFileGetNtAllocProt(paSegments[i].enmProt);
                Status = NtAllocateVirtualMemory(NtCurrentProcess(),
                                                 &pv,
                                                 0,                             /* ZeroBits */
                                                 &ViewSize,
                                                 MEM_COMMIT,
                                                 fPageProt);
            }
            if (!NT_SUCCESS(Status))
                break;
        }

        /*
         * On success, commit the mapping and return.
         */
        if (NT_SUCCESS(Status))
        {
            pRdrFile->cPreps++;
            return 0;
        }

        /* bail out and fall back on the generic code. */
        while (i-- > 0)
        {
            PVOID pv;

            if (paSegments[i].RVA == NIL_KLDRADDR)
                continue;

            pv = (uint8_t *)pPrep->pv + paSegments[i].RVA;
            if (paSegments[i].cbFile > 0)
                NtUnmapViewOfSection(NtCurrentProcess(), pv);
            else
                NtFreeVirtualMemory(NtCurrentProcess(), &pv, NULL, MEM_RELEASE);
        }
        NtClose(pPrep->hSection);
    }
    /* else: fall back to the generic code */
    pPrep->hSection = NULL;
#endif

    /*
     * Use the generic map emulation.
     */
    pPrep->pv = fFixed ? *ppvBase : NULL;
    rc = kldrRdrFileGenericMap(pRdr, pPrep, cSegments, paSegments, fFixed);
    if (!rc)
    {
        *ppvBase = pPrep->pv;
        pRdrFile->cPreps++;
    }

    return rc;
}


/** Generic implementation of kldrRdrFileMap. */
static int  kldrRdrFileGenericMap(PKLDRRDR pRdr, PKLDRRDRFILEPREP pPrep, uint32_t cSegments, PCKLDRSEG paSegments, unsigned fFixed)
{
    int rc;
    uint32_t i;

    /*
     * Generic mapping code using kldrHlpPageAlloc(), kldrHlpPageFree() and kldrHlpPageProtect().
     */
    rc = kldrHlpPageAlloc(&pPrep->pv, pPrep->cb, KLDRPROT_EXECUTE_READWRITE, fFixed);
    if (rc)
        return rc;

    /*
     * Load the data.
     */
    for (i = 0; i < cSegments; i++)
    {
        void *pv;

        if (    paSegments[i].RVA == NIL_KLDRADDR
            ||  paSegments[i].cbFile <= 0)
            continue;

        pv = (uint8_t *)pPrep->pv + paSegments[i].RVA;
        rc = pRdr->pOps->pfnRead(pRdr, pv, paSegments[i].cbFile, paSegments[i].offFile);
        if (rc)
            break;
    }

    /*
     * Set segment protection.
     */
    if (!rc)
    {
        rc = kldrRdrFileGenericProtect(pRdr, pPrep, cSegments, paSegments, 0 /* protect */);
        if (!rc)
            return 0;
        kldrRdrFileGenericProtect(pRdr, pPrep, cSegments, paSegments, 1 /* unprotect */);
    }

    /* bailout */
    kldrHlpPageFree(pPrep->pv, pPrep->cb);
    return rc;
}


/** @copydoc KLDRRDR::pfnPageSize */
static size_t   kldrRdrFilePageSize(PKLDRRDR pRdr)
{
#ifdef __OS2__
    /* The page size on OS/2 wont change anytime soon. :-) */
    return 0x1000;

#elif defined(__WIN__)
    SYSTEM_INFO SysInfo;
    GetSystemInfo(&SysInfo);
    return SysInfo.dwPageSize;
    /*return SysInfo.dwAllocationGranularity;*/
#else
# error "port me"
#endif
}


/** @copydoc KLDRRDR::pfnName */
static const char *kldrRdrFileName(PKLDRRDR pRdr)
{
    PKLDRRDRFILE pRdrFile = (PKLDRRDRFILE)pRdr;
    return &pRdrFile->szFilename[0];
}


/** @copydoc KLDRRDR::pfnTell */
static KLDRFOFF kldrRdrFileTell(PKLDRRDR pRdr)
{
    PKLDRRDRFILE pRdrFile = (PKLDRRDRFILE)pRdr;

    /*
     * If the offset is undefined, try figure out what it is.
     */
    if (pRdrFile->off == -1)
    {
#ifdef __OS2__
        ULONG ulNew;
        APIRET rc = DosSetFilePtr(pRdrFile->File, 0, FILE_CURRENT, &ulNew);
        if (rc)
            return -1;
        pRdrFile->off = ulNew;

#elif defined(__WIN__)
        LONG offHigh = 0;
        LONG offLow;
        int rc;

        SetLastError(0);
        offLow = SetFilePointer(pRdrFile->File, 0, &offHigh, FILE_CURRENT);
        rc = GetLastError();
        if (rc)
            return -1;
        pRdrFile->off = ((KLDRFOFF)offHigh << 32) | offLow;

#else
# error "port me."
#endif
    }
    return pRdrFile->off;
}


/** @copydoc KLDRRDR::pfnSize */
static KLDRFOFF kldrRdrFileSize(PKLDRRDR pRdr)
{
    PKLDRRDRFILE pRdrFile = (PKLDRRDRFILE)pRdr;
    return pRdrFile->cb;
}


/** @copydoc KLDRRDR::pfnAllUnmap */
static int kldrRdrFileAllUnmap(PKLDRRDR pRdr, const void *pvBits)
{
    PKLDRRDRFILE pRdrFile = (PKLDRRDRFILE)pRdr;

    /* check for underflow */
    if (pRdrFile->cMappings <= 0)
#if defined(__OS2__) || defined(__WIN__)
        return ERROR_INVALID_PARAMETER;
#else
# error "port me"
#endif

    /* decrement usage counter, free mapping if no longer in use. */
    if (!--pRdrFile->cMappings)
    {
        kldrHlpFree(pRdrFile->pvMapping);
        pRdrFile->pvMapping = NULL;
    }

    return 0;
}


/** @copydoc KLDRRDR::pfnAllMap */
static int kldrRdrFileAllMap(PKLDRRDR pRdr, const void **ppvBits)
{
    PKLDRRDRFILE pRdrFile = (PKLDRRDRFILE)pRdr;

    /*
     * Do we need to map it?
     */
    if (!pRdrFile->pvMapping)
    {
        int rc;
        KLDRFOFF cb = pRdrFile->Core.pOps->pfnSize(pRdr);

        pRdrFile->pvMapping = kldrHlpAlloc(cb);
        if (!pRdrFile->pvMapping)
#if defined(__OS2__) || defined(__WIN__)
            return ERROR_NOT_ENOUGH_MEMORY;
#else
# error "port me"
#endif
        rc = pRdrFile->Core.pOps->pfnRead(pRdr, pRdrFile->pvMapping, cb, 0);
        if (rc)
        {
            kldrHlpFree(pRdrFile->pvMapping);
            pRdrFile->pvMapping = NULL;
            return rc;
        }
        pRdrFile->cMappings = 0;
    }

    *ppvBits = pRdrFile->pvMapping;
    pRdrFile->cMappings++;
    return 0;
}


/** @copydoc KLDRRDR::pfnRead */
static int kldrRdrFileRead(PKLDRRDR pRdr, void *pvBuf, size_t cb, KLDRFOFF off)
{
    PKLDRRDRFILE pRdrFile = (PKLDRRDRFILE)pRdr;

    /*
     * Do a seek if needed.
     */
    if (pRdrFile->off != off)
    {
#ifdef __OS2__
        ULONG ulNew;
        APIRET rc;

        rc = DosSetFilePtr(pRdrFile->File, off, FILE_BEGIN, &ulNew);
        if (rc)
        {
            pRdrFile->off = -1;
            return rc;
        }

#elif defined(__WIN__)
        LONG offHigh;
        LONG offLow;

        offHigh = sizeof(KLDRFOFF) == 4 ? 0 : (off >> 32);
        offLow = SetFilePointer(pRdrFile->File, (LONG)off, &offHigh, FILE_BEGIN);
        if (    offLow != (LONG)off
            ||  offHigh != (LONG)(sizeof(KLDRFOFF) == 4 ? 0 : (off >> 32)))
        {
            int rc = GetLastError();
            if (!rc)
                rc = ERROR_GEN_FAILURE;
            pRdrFile->off = -1;
            return rc;
        }

#else
# error "port me."
#endif
    }

    /*
     * Do the read.
     */
#ifdef __OS2__
    {
    ULONG cbRead = 0;
    APIRET rc = DosRead(pRdrFile->File, pvBuf, cb, &cbRead);
    if (rc)
    {
        pRdrFile->off = -1;
        return rc;
    }
    if (cbRead != cb)
    {
        pRdrFile->off = -1;
        return ERROR_GEN_FAILURE;
    }
    }

#elif defined(__WIN__)
    {
    DWORD cbRead = 0;
    if (!ReadFile(pRdrFile->File, pvBuf, cb, &cbRead, NULL))
    {
        int rc = GetLastError();
        if (!rc)
            rc = ERROR_GEN_FAILURE;
        pRdrFile->off = -1;
        return rc;
    }
    if (cbRead != cb)
    {
        pRdrFile->off = -1;
        return ERROR_GEN_FAILURE;
    }
    }

#else
# error "port me."
#endif

    pRdrFile->off = off + cb;
    return 0;
}


/** @copydoc KLDRRDR::pfnDestroy */
static int kldrRdrFileDestroy(PKLDRRDR pRdr)
{
    PKLDRRDRFILE    pRdrFile = (PKLDRRDRFILE)pRdr;
    int             rc;
#ifdef __OS2__
    rc = DosClose(pRdrFile->File);

#elif defined(__WIN__)
    rc = 0;
    if (!CloseHandle(pRdrFile->File))
        rc = GetLastError();

#else
# error "port me"
#endif

    if (pRdrFile->pvMapping)
    {
        kldrHlpFree(pRdrFile->pvMapping);
        pRdrFile->pvMapping = NULL;
    }

    kldrHlpFree(pRdr);
    return rc;
}


/** @copydoc KLDRRDROPS::pfnCreate */
static int kldrRdrFileCreate(PPKLDRRDR ppRdr, const char *pszFilename)
{
    size_t          cchFilename;
    PKLDRRDRFILE    pRdrFile;

    /*
     * Open the file and determin its size.
     */
#ifdef __OS2__
    ULONG           ulAction = 0;
    FILESTATUS3     Info;
    APIRET          rc;
    HFILE           File = 0;
    KLDRFOFF        cb;
    char            szFilename[CCHMAXPATH];

    if ((uintptr_t)pszFilename >= 0x20000000)
    {
        char *psz;
        cchFilename = kLdrHlpStrLen(szFilename);
        psz = (char *)kLdrHlpAllocA(cchFilename + 1);
        kLdrHlpMemCopy(psz, pszFilename, cchFilename + 1);
        pszFilename = psz;
    }
    rc = DosOpen((PCSZ)pszFilename, &File, &ulAction, 0, FILE_NORMAL,
                 OPEN_ACTION_OPEN_IF_EXISTS | OPEN_ACTION_FAIL_IF_NEW,
                 OPEN_FLAGS_NOINHERIT | OPEN_SHARE_DENYWRITE | OPEN_ACCESS_READONLY | OPEN_FLAGS_RANDOMSEQUENTIAL,
                 NULL);
    if (rc)
        return rc;

    rc = DosQueryPathInfo((PCSZ)pszFilename, FIL_QUERYFULLNAME, szFilename, sizeof(szFilename));
    if (rc)
    {
        DosClose(File);
        return rc;
    }

    rc = DosQueryFileInfo(File, FIL_STANDARD, &Info, sizeof(Info));
    if (rc)
    {
        DosClose(File);
        return rc;
    }
    cb = Info.cbFile;

#elif defined(__WIN__)
    SECURITY_ATTRIBUTES SecAttr;
    DWORD               High;
    DWORD               Low;
    int                 rc;
    HANDLE              File;
    KLDRFOFF            cb;
    char                szFilename[MAX_PATH];

    SecAttr.bInheritHandle = FALSE;
    SecAttr.lpSecurityDescriptor = NULL;
    SecAttr.nLength = 0;
    File = CreateFile(pszFilename, GENERIC_READ | GENERIC_EXECUTE, FILE_SHARE_READ, &SecAttr, OPEN_EXISTING, 0, NULL);
    if (File == INVALID_HANDLE_VALUE)
        return GetLastError();

    if (!GetFullPathName(pszFilename, sizeof(szFilename), szFilename, NULL))
    {
        rc = GetLastError();
        CloseHandle(File);
        return rc;
    }

    SetLastError(0);
    Low = GetFileSize(File, &High);
    rc = GetLastError();
    if (rc)
    {
        CloseHandle(File);
        return rc;
    }
    if (sizeof(KLDRFOFF) == 4)
        cb = High ? 0x7fffffff : Low;
    else
        cb = ((KLDRFOFF)High << 32) | Low;

#else
# error "port me"
#endif


    /*
     * Allocate the reader instance.
     */
    cchFilename = kLdrHlpStrLen(szFilename);
    pRdrFile = (PKLDRRDRFILE)kldrHlpAlloc(sizeof(*pRdrFile) + cchFilename);
    if (!pRdrFile)
#if defined(__OS2__)
    {
        DosClose(File);
        return ERROR_NOT_ENOUGH_MEMORY;
    }
#elif defined(__WIN__)
    {
        CloseHandle(File);
        return ERROR_NOT_ENOUGH_MEMORY;
    }
#else
# error "port me"
#endif

    /*
     * Initialize it and return successfully.
     */
    pRdrFile->Core.u32Magic = KLDRRDR_MAGIC;
    pRdrFile->Core.pOps = &g_kLdrRdrFileOps;
    pRdrFile->File = File;
    pRdrFile->cb = cb;
    pRdrFile->off = 0;
    pRdrFile->cMappings = 0;
    pRdrFile->cPreps = 0;
    kLdrHlpMemCopy(&pRdrFile->szFilename[0], szFilename, cchFilename + 1);

    *ppRdr = &pRdrFile->Core;
    return 0;
}