path: root/src/H5FDsec2.c

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the COPYING file, which can be found at the root of the source code       *
 * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
 * If you do not have access to either file, you may request a copy from     *
 * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
 * Programmer:  Robb Matzke <matzke@llnl.gov>
 *              Thursday, July 29, 1999
 *
 * Purpose: The POSIX unbuffered file driver using only the HDF5 public
 *          API and with a few optimizations: the lseek() call is made
 *          only when the current file position is unknown or needs to be
 *          changed based on previous I/O through this driver (don't mix
 *          I/O from this driver with I/O from other parts of the
 *          application to the same file).
 */

#include "H5FDdrvr_module.h" /* This source code file is part of the H5FD driver module */


#include "H5private.h"      /* Generic Functions        */
#include "H5Eprivate.h"     /* Error handling           */
#include "H5Fprivate.h"     /* File access              */
#include "H5FDprivate.h"    /* File drivers             */
#include "H5FDsec2.h"       /* Sec2 file driver         */
#include "H5FLprivate.h"    /* Free Lists               */
#include "H5Iprivate.h"     /* IDs                      */
#include "H5MMprivate.h"    /* Memory management        */
#include "H5Pprivate.h"     /* Property lists           */

/* The driver identification number, initialized at runtime */
static hid_t H5FD_SEC2_g = 0;

/* The description of a file belonging to this driver. The 'eoa' and 'eof'
 * determine the amount of hdf5 address space in use and the high-water mark
 * of the file (the current size of the underlying filesystem file). The
 * 'pos' value is used to eliminate file position updates when they would be a
 * no-op. Unfortunately we've found systems that use separate file position
 * indicators for reading and writing so the lseek can only be eliminated if
 * the current operation is the same as the previous operation.  When opening
 * a file the 'eof' will be set to the current file size, `eoa' will be set
 * to zero, 'pos' will be set to H5F_ADDR_UNDEF (as it is when an error
 * occurs), and 'op' will be set to H5F_OP_UNKNOWN.
 */
typedef struct H5FD_sec2_t {
    H5FD_t          pub;    /* public stuff, must be first      */
    int             fd;     /* the filesystem file descriptor   */
    haddr_t         eoa;    /* end of allocated region          */
    haddr_t         eof;    /* end of file; current file size   */
    haddr_t         pos;    /* current file I/O position        */
    H5FD_file_op_t  op;     /* last operation                   */
    char            filename[H5FD_MAX_FILENAME_LEN];    /* Copy of file name from open operation */
#ifndef H5_HAVE_WIN32_API
    /* On most systems the combination of device and i-node number uniquely
     * identify a file.  Note that Cygwin, MinGW and other Windows POSIX
     * environments have the stat function (which fakes inodes)
     * and will use the 'device + inodes' scheme as opposed to the
     * Windows code further below.
     */
    dev_t           device;     /* file device number   */
    ino_t           inode;      /* file i-node number   */
#else
    /* Files in windows are uniquely identified by the volume serial
     * number and the file index (both low and high parts).
     *
     * There are caveats where these numbers can change, especially
     * on FAT file systems.  On NTFS, however, a file should keep
     * those numbers the same until renamed or deleted (though you
     * can use ReplaceFile() on NTFS to keep the numbers the same
     * while renaming).
     *
     * See the MSDN "BY_HANDLE_FILE_INFORMATION Structure" entry for
     * more information.
     *
     * http://msdn.microsoft.com/en-us/library/aa363788(v=VS.85).aspx
     */
    DWORD           nFileIndexLow;
    DWORD           nFileIndexHigh;
    DWORD           dwVolumeSerialNumber;
    
    HANDLE          hFile;      /* Native windows file handle */
#endif  /* H5_HAVE_WIN32_API */

    /* Information from properties set by 'h5repart' tool
     *
     * Whether to eliminate the family driver info and convert this file to
     * a single file.
     */
    hbool_t         fam_to_sec2;

} H5FD_sec2_t;

/*
 * These macros check for overflow of various quantities.  These macros
 * assume that HDoff_t is signed and haddr_t and size_t are unsigned.
 *
 * ADDR_OVERFLOW:   Checks whether a file address of type `haddr_t'
 *                  is too large to be represented by the second argument
 *                  of the file seek function.
 *
 * SIZE_OVERFLOW:   Checks whether a buffer size of type `hsize_t' is too
 *                  large to be represented by the `size_t' type.
 *
 * REGION_OVERFLOW: Checks whether an address and size pair describe data
 *                  which can be addressed entirely by the second
 *                  argument of the file seek function.
 */
#define MAXADDR (((haddr_t)1<<(8*sizeof(HDoff_t)-1))-1)
#define ADDR_OVERFLOW(A)    (HADDR_UNDEF==(A) || ((A) & ~(haddr_t)MAXADDR))
#define SIZE_OVERFLOW(Z)    ((Z) & ~(hsize_t)MAXADDR)
#define REGION_OVERFLOW(A,Z)    (ADDR_OVERFLOW(A) || SIZE_OVERFLOW(Z) ||    \
                                 HADDR_UNDEF==(A)+(Z) ||                    \
                                (HDoff_t)((A)+(Z))<(HDoff_t)(A))

/* Prototypes */
static herr_t H5FD_sec2_term(void);
static H5FD_t *H5FD_sec2_open(const char *name, unsigned flags, hid_t fapl_id,
            haddr_t maxaddr);
static herr_t H5FD_sec2_close(H5FD_t *_file);
static int H5FD_sec2_cmp(const H5FD_t *_f1, const H5FD_t *_f2);
static herr_t H5FD_sec2_query(const H5FD_t *_f1, unsigned long *flags);
static haddr_t H5FD_sec2_get_eoa(const H5FD_t *_file, H5FD_mem_t type);
static herr_t H5FD_sec2_set_eoa(H5FD_t *_file, H5FD_mem_t type, haddr_t addr);
static haddr_t H5FD_sec2_get_eof(const H5FD_t *_file, H5FD_mem_t type);
static herr_t  H5FD_sec2_get_handle(H5FD_t *_file, hid_t fapl, void** file_handle);
static herr_t H5FD_sec2_read(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id, haddr_t addr,
            size_t size, void *buf);
static herr_t H5FD_sec2_write(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id, haddr_t addr,
            size_t size, const void *buf);
static herr_t H5FD_sec2_truncate(H5FD_t *_file, hid_t dxpl_id, hbool_t closing);
static herr_t H5FD_sec2_lock(H5FD_t *_file, hbool_t rw);
static herr_t H5FD_sec2_unlock(H5FD_t *_file);

static const H5FD_class_t H5FD_sec2_g = {
    "sec2",                     /* name                 */
    MAXADDR,                    /* maxaddr              */
    H5F_CLOSE_WEAK,             /* fc_degree            */
    H5FD_sec2_term,             /* terminate            */
    NULL,                       /* sb_size              */
    NULL,                       /* sb_encode            */
    NULL,                       /* sb_decode            */
    0,                          /* fapl_size            */
    NULL,                       /* fapl_get             */
    NULL,                       /* fapl_copy            */
    NULL,                       /* fapl_free            */
    0,                          /* dxpl_size            */
    NULL,                       /* dxpl_copy            */
    NULL,                       /* dxpl_free            */
    H5FD_sec2_open,             /* open                 */
    H5FD_sec2_close,            /* close                */
    H5FD_sec2_cmp,              /* cmp                  */
    H5FD_sec2_query,            /* query                */
    NULL,                       /* get_type_map         */
    NULL,                       /* alloc                */
    NULL,                       /* free                 */
    H5FD_sec2_get_eoa,          /* get_eoa              */
    H5FD_sec2_set_eoa,          /* set_eoa              */
    H5FD_sec2_get_eof,          /* get_eof              */
    H5FD_sec2_get_handle,       /* get_handle           */
    H5FD_sec2_read,             /* read                 */
    H5FD_sec2_write,            /* write                */
    NULL,                       /* flush                */
    H5FD_sec2_truncate,         /* truncate             */
    H5FD_sec2_lock,             /* lock                 */
    H5FD_sec2_unlock,           /* unlock               */
    H5FD_FLMAP_DICHOTOMY        /* fl_map               */
};

/* Declare a free list to manage the H5FD_sec2_t struct */
H5FL_DEFINE_STATIC(H5FD_sec2_t);


/*-------------------------------------------------------------------------
 * Function:    H5FD__init_package
 *
 * Purpose:     Initializes any interface-specific data or routines.
 *
 * Return:      Non-negative on success/Negative on failure
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD__init_package(void)
{
    herr_t ret_value = SUCCEED;

    FUNC_ENTER_STATIC

    if(H5FD_sec2_init() < 0)
        HGOTO_ERROR(H5E_VFL, H5E_CANTINIT, FAIL, "unable to initialize sec2 VFD")

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* H5FD__init_package() */


/*-------------------------------------------------------------------------
 * Function:    H5FD_sec2_init
 *
 * Purpose:     Initialize this driver by registering the driver with the
 *              library.
 *
 * Return:      Success:    The driver ID for the sec2 driver.
 *              Failure:    Negative
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
hid_t
H5FD_sec2_init(void)
{
    hid_t ret_value = H5I_INVALID_HID;          /* Return value */

    FUNC_ENTER_NOAPI(FAIL)

    if(H5I_VFL != H5I_get_type(H5FD_SEC2_g))
        H5FD_SEC2_g = H5FD_register(&H5FD_sec2_g, sizeof(H5FD_class_t), FALSE);

    /* Set return value */
    ret_value = H5FD_SEC2_g;

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_sec2_init() */


/*---------------------------------------------------------------------------
 * Function:    H5FD_sec2_term
 *
 * Purpose:     Shut down the VFD
 *
 * Returns:     SUCCEED (Can't fail)
 *
 * Programmer:  Quincey Koziol
 *              Friday, Jan 30, 2004
 *
 *---------------------------------------------------------------------------
 */
static herr_t
H5FD_sec2_term(void)
{
    FUNC_ENTER_NOAPI_NOINIT_NOERR

    /* Reset VFL ID */
    H5FD_SEC2_g = 0;

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5FD_sec2_term() */


/*-------------------------------------------------------------------------
 * Function:    H5Pset_fapl_sec2
 *
 * Purpose:     Modify the file access property list to use the H5FD_SEC2
 *              driver defined in this source file.  There are no driver
 *              specific properties.
 *
 * Return:      SUCCEED/FAIL
 *
 * Programmer:  Robb Matzke
 *              Thursday, February 19, 1998
 *
 *-------------------------------------------------------------------------
 */
herr_t
H5Pset_fapl_sec2(hid_t fapl_id)
{
    H5P_genplist_t *plist;      /* Property list pointer */
    herr_t ret_value;

    FUNC_ENTER_API(FAIL)
    H5TRACE1("e", "i", fapl_id);

    if(NULL == (plist = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file access property list")

    ret_value = H5P_set_driver(plist, H5FD_SEC2, NULL);

done:
    FUNC_LEAVE_API(ret_value)
} /* end H5Pset_fapl_sec2() */


/*-------------------------------------------------------------------------
 * Function:    H5FD_sec2_open
 *
 * Purpose:     Create and/or opens a file as an HDF5 file.
 *
 * Return:      Success:    A pointer to a new file data structure. The
 *                          public fields will be initialized by the
 *                          caller, which is always H5FD_open().
 *              Failure:    NULL
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
static H5FD_t *
H5FD_sec2_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t maxaddr)
{
    H5FD_sec2_t     *file       = NULL;     /* sec2 VFD info            */
    int             fd          = -1;       /* File descriptor          */
    int             o_flags;                /* Flags for open() call    */
#ifdef H5_HAVE_WIN32_API
    struct _BY_HANDLE_FILE_INFORMATION fileinfo;
#endif
    h5_stat_t       sb;
    H5FD_t          *ret_value = NULL;          /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Sanity check on file offsets */
    HDcompile_assert(sizeof(HDoff_t) >= sizeof(size_t));

    /* Check arguments */
    if(!name || !*name)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "invalid file name")
    if(0 == maxaddr || HADDR_UNDEF == maxaddr)
        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, NULL, "bogus maxaddr")
    if(ADDR_OVERFLOW(maxaddr))
        HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, NULL, "bogus maxaddr")

    /* Build the open flags */
    o_flags = (H5F_ACC_RDWR & flags) ? O_RDWR : O_RDONLY;
    if(H5F_ACC_TRUNC & flags)
        o_flags |= O_TRUNC;
    if(H5F_ACC_CREAT & flags)
        o_flags |= O_CREAT;
    if(H5F_ACC_EXCL & flags)
        o_flags |= O_EXCL;

    /* Open the file */
    if((fd = HDopen(name, o_flags, 0666)) < 0) {
        int myerrno = errno;
        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to open file: name = '%s', errno = %d, error message = '%s', flags = %x, o_flags = %x", name, myerrno, HDstrerror(myerrno), flags, (unsigned)o_flags);
    } /* end if */

    if(HDfstat(fd, &sb) < 0)
        HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, NULL, "unable to fstat file")

    /* Create the new file struct */
    if(NULL == (file = H5FL_CALLOC(H5FD_sec2_t)))
        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "unable to allocate file struct")

    file->fd = fd;
    H5_CHECKED_ASSIGN(file->eof, haddr_t, sb.st_size, h5_stat_size_t);
    file->pos = HADDR_UNDEF;
    file->op = OP_UNKNOWN;
#ifdef H5_HAVE_WIN32_API
    file->hFile = (HANDLE)_get_osfhandle(fd);
    if(INVALID_HANDLE_VALUE == file->hFile)
        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to get Windows file handle")

    if(!GetFileInformationByHandle((HANDLE)file->hFile, &fileinfo))
        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to get Windows file information")

    file->nFileIndexHigh = fileinfo.nFileIndexHigh;
    file->nFileIndexLow = fileinfo.nFileIndexLow;
    file->dwVolumeSerialNumber = fileinfo.dwVolumeSerialNumber;
#else /* H5_HAVE_WIN32_API */
    file->device = sb.st_dev;
    file->inode = sb.st_ino;
#endif /* H5_HAVE_WIN32_API */

    /* Retain a copy of the name used to open the file, for possible error reporting */
    HDstrncpy(file->filename, name, sizeof(file->filename));
    file->filename[sizeof(file->filename) - 1] = '\0';

    /* Check for non-default FAPL */
    if(H5P_FILE_ACCESS_DEFAULT != fapl_id) {
        H5P_genplist_t      *plist;      /* Property list pointer */

        /* Get the FAPL */
        if(NULL == (plist = (H5P_genplist_t *)H5I_object(fapl_id)))
            HGOTO_ERROR(H5E_VFL, H5E_BADTYPE, NULL, "not a file access property list")

        /* This step is for h5repart tool only. If user wants to change file driver from
         * family to sec2 while using h5repart, this private property should be set so that
         * in the later step, the library can ignore the family driver information saved
         * in the superblock.
         */
        if(H5P_exist_plist(plist, H5F_ACS_FAMILY_TO_SEC2_NAME) > 0)
            if(H5P_get(plist, H5F_ACS_FAMILY_TO_SEC2_NAME, &file->fam_to_sec2) < 0)
                HGOTO_ERROR(H5E_VFL, H5E_CANTGET, NULL, "can't get property of changing family to sec2")
    } /* end if */

    /* Set return value */
    ret_value = (H5FD_t*)file;

done:
    if(NULL == ret_value) {
        if(fd >= 0)
            HDclose(fd);
        if(file)
            file = H5FL_FREE(H5FD_sec2_t, file);
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_sec2_open() */


/*-------------------------------------------------------------------------
 * Function:    H5FD_sec2_close
 *
 * Purpose:     Closes an HDF5 file.
 *
 * Return:      Success:    SUCCEED
 *              Failure:    FAIL, file not closed.
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_sec2_close(H5FD_t *_file)
{
    H5FD_sec2_t *file = (H5FD_sec2_t *)_file;
    herr_t      ret_value = SUCCEED;                /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    /* Sanity check */
    HDassert(file);

    /* Close the underlying file */
    if(HDclose(file->fd) < 0)
        HSYS_GOTO_ERROR(H5E_IO, H5E_CANTCLOSEFILE, FAIL, "unable to close file")

    /* Release the file info */
    file = H5FL_FREE(H5FD_sec2_t, file);

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_sec2_close() */


/*-------------------------------------------------------------------------
 * Function:    H5FD_sec2_cmp
 *
 * Purpose:     Compares two files belonging to this driver using an
 *              arbitrary (but consistent) ordering.
 *
 * Return:      Success:    A value like strcmp()
 *              Failure:    never fails (arguments were checked by the
 *                          caller).
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
static int
H5FD_sec2_cmp(const H5FD_t *_f1, const H5FD_t *_f2)
{
    const H5FD_sec2_t   *f1 = (const H5FD_sec2_t *)_f1;
    const H5FD_sec2_t   *f2 = (const H5FD_sec2_t *)_f2;
    int ret_value = 0;

    FUNC_ENTER_NOAPI_NOINIT_NOERR

#ifdef H5_HAVE_WIN32_API
    if(f1->dwVolumeSerialNumber < f2->dwVolumeSerialNumber) HGOTO_DONE(-1)
    if(f1->dwVolumeSerialNumber > f2->dwVolumeSerialNumber) HGOTO_DONE(1)

    if(f1->nFileIndexHigh < f2->nFileIndexHigh) HGOTO_DONE(-1)
    if(f1->nFileIndexHigh > f2->nFileIndexHigh) HGOTO_DONE(1)

    if(f1->nFileIndexLow < f2->nFileIndexLow) HGOTO_DONE(-1)
    if(f1->nFileIndexLow > f2->nFileIndexLow) HGOTO_DONE(1)
#else /* H5_HAVE_WIN32_API */
#ifdef H5_DEV_T_IS_SCALAR
    if(f1->device < f2->device) HGOTO_DONE(-1)
    if(f1->device > f2->device) HGOTO_DONE(1)
#else /* H5_DEV_T_IS_SCALAR */
    /* If dev_t isn't a scalar value on this system, just use memcmp to
     * determine if the values are the same or not.  The actual return value
     * shouldn't really matter...
     */
    if(HDmemcmp(&(f1->device),&(f2->device),sizeof(dev_t)) < 0) HGOTO_DONE(-1)
    if(HDmemcmp(&(f1->device),&(f2->device),sizeof(dev_t)) > 0) HGOTO_DONE(1)
#endif /* H5_DEV_T_IS_SCALAR */
    if(f1->inode < f2->inode) HGOTO_DONE(-1)
    if(f1->inode > f2->inode) HGOTO_DONE(1)
#endif /* H5_HAVE_WIN32_API */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_sec2_cmp() */


/*-------------------------------------------------------------------------
 * Function:    H5FD_sec2_query
 *
 * Purpose:     Set the flags that this VFL driver is capable of supporting.
 *              (listed in H5FDpublic.h)
 *
 * Return:      SUCCEED (Can't fail)
 *
 * Programmer:  Quincey Koziol
 *              Friday, August 25, 2000
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_sec2_query(const H5FD_t *_file, unsigned long *flags /* out */)
{
    const H5FD_sec2_t	*file = (const H5FD_sec2_t *)_file;    /* sec2 VFD info */

    FUNC_ENTER_NOAPI_NOINIT_NOERR

    /* Set the VFL feature flags that this driver supports */
    if(flags) {
        *flags = 0;
        *flags |= H5FD_FEAT_AGGREGATE_METADATA;     /* OK to aggregate metadata allocations                             */
        *flags |= H5FD_FEAT_ACCUMULATE_METADATA;    /* OK to accumulate metadata for faster writes                      */
        *flags |= H5FD_FEAT_DATA_SIEVE;             /* OK to perform data sieving for faster raw data reads & writes    */
        *flags |= H5FD_FEAT_AGGREGATE_SMALLDATA;    /* OK to aggregate "small" raw data allocations                     */
        *flags |= H5FD_FEAT_POSIX_COMPAT_HANDLE;    /* VFD handle is POSIX I/O call compatible                          */
        *flags |= H5FD_FEAT_SUPPORTS_SWMR_IO;       /* VFD supports the single-writer/multiple-readers (SWMR) pattern   */

        /* Check for flags that are set by h5repart */
        if(file && file->fam_to_sec2)
            *flags |= H5FD_FEAT_IGNORE_DRVRINFO; /* Ignore the driver info when file is opened (which eliminates it) */
    } /* end if */

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5FD_sec2_query() */


/*-------------------------------------------------------------------------
 * Function:    H5FD_sec2_get_eoa
 *
 * Purpose:     Gets the end-of-address marker for the file. The EOA marker
 *              is the first address past the last byte allocated in the
 *              format address space.
 *
 * Return:      The end-of-address marker.
 *
 * Programmer:  Robb Matzke
 *              Monday, August  2, 1999
 *
 *-------------------------------------------------------------------------
 */
static haddr_t
H5FD_sec2_get_eoa(const H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type)
{
    const H5FD_sec2_t	*file = (const H5FD_sec2_t *)_file;

    FUNC_ENTER_NOAPI_NOINIT_NOERR

    FUNC_LEAVE_NOAPI(file->eoa)
} /* end H5FD_sec2_get_eoa() */


/*-------------------------------------------------------------------------
 * Function:    H5FD_sec2_set_eoa
 *
 * Purpose:     Set the end-of-address marker for the file. This function is
 *              called shortly after an existing HDF5 file is opened in order
 *              to tell the driver where the end of the HDF5 data is located.
 *
 * Return:      SUCCEED (Can't fail)
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_sec2_set_eoa(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, haddr_t addr)
{
    H5FD_sec2_t	*file = (H5FD_sec2_t *)_file;

    FUNC_ENTER_NOAPI_NOINIT_NOERR

    file->eoa = addr;

    FUNC_LEAVE_NOAPI(SUCCEED)
} /* end H5FD_sec2_set_eoa() */


/*-------------------------------------------------------------------------
 * Function:    H5FD_sec2_get_eof
 *
 * Purpose:     Returns the end-of-file marker, which is the greater of
 *              either the filesystem end-of-file or the HDF5 end-of-address
 *              markers.
 *
 * Return:      End of file address, the first address past the end of the 
 *              "file", either the filesystem file or the HDF5 file.
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
static haddr_t
H5FD_sec2_get_eof(const H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type)
{
    const H5FD_sec2_t   *file = (const H5FD_sec2_t *)_file;

    FUNC_ENTER_NOAPI_NOINIT_NOERR

    FUNC_LEAVE_NOAPI(file->eof)
} /* end H5FD_sec2_get_eof() */


/*-------------------------------------------------------------------------
 * Function:       H5FD_sec2_get_handle
 *
 * Purpose:        Returns the file handle of sec2 file driver.
 *
 * Returns:        SUCCEED/FAIL
 *
 * Programmer:     Raymond Lu
 *                 Sept. 16, 2002
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_sec2_get_handle(H5FD_t *_file, hid_t H5_ATTR_UNUSED fapl, void **file_handle)
{
    H5FD_sec2_t         *file = (H5FD_sec2_t *)_file;
    herr_t              ret_value = SUCCEED;

    FUNC_ENTER_NOAPI_NOINIT

    if(!file_handle)
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "file handle not valid")

    *file_handle = &(file->fd);

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_sec2_get_handle() */


/*-------------------------------------------------------------------------
 * Function:    H5FD_sec2_read
 *
 * Purpose:     Reads SIZE bytes of data from FILE beginning at address ADDR
 *              into buffer BUF according to data transfer properties in
 *              DXPL_ID.
 *
 * Return:      Success:    SUCCEED. Result is stored in caller-supplied
 *                          buffer BUF.
 *              Failure:    FAIL, Contents of buffer BUF are undefined.
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_sec2_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNUSED dxpl_id,
    haddr_t addr, size_t size, void *buf /*out*/)
{
    H5FD_sec2_t     *file       = (H5FD_sec2_t *)_file;
    herr_t          ret_value   = SUCCEED;                  /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    HDassert(file && file->pub.cls);
    HDassert(buf);

    /* Check for overflow conditions */
    if(!H5F_addr_defined(addr))
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "addr undefined, addr = %llu", (unsigned long long)addr)
    if(REGION_OVERFLOW(addr, size))
        HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, FAIL, "addr overflow, addr = %llu", (unsigned long long)addr)

    /* Seek to the correct location */
    if(addr != file->pos || OP_READ != file->op) {
        if(HDlseek(file->fd, (HDoff_t)addr, SEEK_SET) < 0)
            HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position")
    } /* end if */

    /* Read data, being careful of interrupted system calls, partial results,
     * and the end of the file.
     */
    while(size > 0) {

        h5_posix_io_t       bytes_in        = 0;    /* # of bytes to read       */
        h5_posix_io_ret_t   bytes_read      = -1;   /* # of bytes actually read */ 

        /* Trying to read more bytes than the return type can handle is
         * undefined behavior in POSIX.
         */
        if(size > H5_POSIX_MAX_IO_BYTES)
            bytes_in = H5_POSIX_MAX_IO_BYTES;
        else
            bytes_in = (h5_posix_io_t)size;

        do {
            bytes_read = HDread(file->fd, buf, bytes_in);
        } while(-1 == bytes_read && EINTR == errno);
        
        if(-1 == bytes_read) { /* error */
            int myerrno = errno;
            time_t mytime = HDtime(NULL);
            HDoff_t myoffset = HDlseek(file->fd, (HDoff_t)0, SEEK_CUR);

            HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "file read failed: time = %s, filename = '%s', file descriptor = %d, errno = %d, error message = '%s', buf = %p, total read size = %llu, bytes this sub-read = %llu, bytes actually read = %llu, offset = %llu", HDctime(&mytime), file->filename, file->fd, myerrno, HDstrerror(myerrno), buf, (unsigned long long)size, (unsigned long long)bytes_in, (unsigned long long)bytes_read, (unsigned long long)myoffset);
        } /* end if */
        
        if(0 == bytes_read) {
            /* end of file but not end of format address space */
            HDmemset(buf, 0, size);
            break;
        } /* end if */
        
        HDassert(bytes_read >= 0);
        HDassert((size_t)bytes_read <= size);
        
        size -= (size_t)bytes_read;
        addr += (haddr_t)bytes_read;
        buf = (char *)buf + bytes_read;
    } /* end while */

    /* Update current position */
    file->pos = addr;
    file->op = OP_READ;

done:
    if(ret_value < 0) {
        /* Reset last file I/O information */
        file->pos = HADDR_UNDEF;
        file->op = OP_UNKNOWN;
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_sec2_read() */


/*-------------------------------------------------------------------------
 * Function:    H5FD_sec2_write
 *
 * Purpose:     Writes SIZE bytes of data to FILE beginning at address ADDR
 *              from buffer BUF according to data transfer properties in
 *              DXPL_ID.
 *
 * Return:      SUCCEED/FAIL
 *
 * Programmer:  Robb Matzke
 *              Thursday, July 29, 1999
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_sec2_write(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNUSED dxpl_id,
                haddr_t addr, size_t size, const void *buf)
{
    H5FD_sec2_t     *file       = (H5FD_sec2_t *)_file;
    herr_t          ret_value   = SUCCEED;                  /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    HDassert(file && file->pub.cls);
    HDassert(buf);

    /* Check for overflow conditions */
    if(!H5F_addr_defined(addr))
        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "addr undefined, addr = %llu", (unsigned long long)addr)
    if(REGION_OVERFLOW(addr, size))
        HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, FAIL, "addr overflow, addr = %llu, size = %llu", (unsigned long long)addr, (unsigned long long)size)

    /* Seek to the correct location */
    if(addr != file->pos || OP_WRITE != file->op) {
        if(HDlseek(file->fd, (HDoff_t)addr, SEEK_SET) < 0)
            HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position")
    } /* end if */

    /* Write the data, being careful of interrupted system calls and partial
     * results
     */
    while(size > 0) {

        h5_posix_io_t       bytes_in        = 0;    /* # of bytes to write  */
        h5_posix_io_ret_t   bytes_wrote     = -1;   /* # of bytes written   */ 

        /* Trying to write more bytes than the return type can handle is
         * undefined behavior in POSIX.
         */
        if(size > H5_POSIX_MAX_IO_BYTES)
            bytes_in = H5_POSIX_MAX_IO_BYTES;
        else
            bytes_in = (h5_posix_io_t)size;

        do {
            bytes_wrote = HDwrite(file->fd, buf, bytes_in);
        } while(-1 == bytes_wrote && EINTR == errno);
        
        if(-1 == bytes_wrote) { /* error */
            int myerrno = errno;
            time_t mytime = HDtime(NULL);
            HDoff_t myoffset = HDlseek(file->fd, (HDoff_t)0, SEEK_CUR);

            HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "file write failed: time = %s, filename = '%s', file descriptor = %d, errno = %d, error message = '%s', buf = %p, total write size = %llu, bytes this sub-write = %llu, bytes actually written = %llu, offset = %llu", HDctime(&mytime), file->filename, file->fd, myerrno, HDstrerror(myerrno), buf, (unsigned long long)size, (unsigned long long)bytes_in, (unsigned long long)bytes_wrote, (unsigned long long)myoffset);
        } /* end if */
        
        HDassert(bytes_wrote > 0);
        HDassert((size_t)bytes_wrote <= size);

        size -= (size_t)bytes_wrote;
        addr += (haddr_t)bytes_wrote;
        buf = (const char *)buf + bytes_wrote;
    } /* end while */

    /* Update current position and eof */
    file->pos = addr;
    file->op = OP_WRITE;
    if(file->pos > file->eof)
        file->eof = file->pos;

done:
    if(ret_value < 0) {
        /* Reset last file I/O information */
        file->pos = HADDR_UNDEF;
        file->op = OP_UNKNOWN;
    } /* end if */

    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_sec2_write() */


/*-------------------------------------------------------------------------
 * Function:    H5FD_sec2_truncate
 *
 * Purpose:     Makes sure that the true file size is the same (or larger)
 *              than the end-of-address.
 *
 * Return:      SUCCEED/FAIL
 *
 * Programmer:  Robb Matzke
 *              Wednesday, August  4, 1999
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_sec2_truncate(H5FD_t *_file, hid_t H5_ATTR_UNUSED dxpl_id, hbool_t H5_ATTR_UNUSED closing)
{
    H5FD_sec2_t *file = (H5FD_sec2_t *)_file;
    herr_t ret_value = SUCCEED;                 /* Return value */

    FUNC_ENTER_NOAPI_NOINIT

    HDassert(file);

    /* Extend the file to make sure it's large enough */
    if(!H5F_addr_eq(file->eoa, file->eof)) {
#ifdef H5_HAVE_WIN32_API
        LARGE_INTEGER   li;         /* 64-bit (union) integer for SetFilePointer() call */
        DWORD           dwPtrLow;   /* Low-order pointer bits from SetFilePointer()
                                     * Only used as an error code here.
                                     */
        DWORD           dwError;    /* DWORD error code from GetLastError() */
        BOOL            bError;     /* Boolean error flag */

        /* Windows uses this odd QuadPart union for 32/64-bit portability */
        li.QuadPart = (__int64)file->eoa;

        /* Extend the file to make sure it's large enough.
         *
         * Since INVALID_SET_FILE_POINTER can technically be a valid return value
         * from SetFilePointer(), we also need to check GetLastError().
         */
        dwPtrLow = SetFilePointer(file->hFile, li.LowPart, &li.HighPart, FILE_BEGIN);
        if(INVALID_SET_FILE_POINTER == dwPtrLow) {
            dwError = GetLastError();
            if(dwError != NO_ERROR )
                HGOTO_ERROR(H5E_FILE, H5E_FILEOPEN, FAIL, "unable to set file pointer")
        }

        bError = SetEndOfFile(file->hFile);
        if(0 == bError)
            HGOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
#else /* H5_HAVE_WIN32_API */
        if(-1 == HDftruncate(file->fd, (HDoff_t)file->eoa))
            HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
#endif /* H5_HAVE_WIN32_API */

        /* Update the eof value */
        file->eof = file->eoa;

        /* Reset last file I/O information */
        file->pos = HADDR_UNDEF;
        file->op = OP_UNKNOWN;
    } /* end if */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_sec2_truncate() */


/*-------------------------------------------------------------------------
 * Function:    H5FD_sec2_lock
 *
 * Purpose:     To place an advisory lock on a file.
 *		The lock type to apply depends on the parameter "rw":
 *			TRUE--opens for write: an exclusive lock
 *			FALSE--opens for read: a shared lock
 *
 * Return:      SUCCEED/FAIL
 *
 * Programmer:  Vailin Choi; May 2013
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_sec2_lock(H5FD_t *_file, hbool_t rw)
{
    H5FD_sec2_t *file = (H5FD_sec2_t *)_file;   /* VFD file struct          */
    int lock_flags;                             /* file locking flags       */
    herr_t ret_value = SUCCEED;                 /* Return value             */

    FUNC_ENTER_NOAPI_NOINIT

    HDassert(file);

    /* Set exclusive or shared lock based on rw status */
    lock_flags = rw ? LOCK_EX : LOCK_SH;

    /* Place a non-blocking lock on the file */
    if(HDflock(file->fd, lock_flags | LOCK_NB) < 0) {
        if(ENOSYS == errno)
            HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, FAIL, "file locking disabled on this file system (use HDF5_USE_FILE_LOCKING environment variable to override)")
        else
            HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, FAIL, "unable to lock file")
    } /* end if */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_sec2_lock() */


/*-------------------------------------------------------------------------
 * Function:    H5FD_sec2_unlock
 *
 * Purpose:     To remove the existing lock on the file
 *
 * Return:      SUCCEED/FAIL
 *
 * Programmer:  Vailin Choi; May 2013
 *
 *-------------------------------------------------------------------------
 */
static herr_t
H5FD_sec2_unlock(H5FD_t *_file)
{
    H5FD_sec2_t *file = (H5FD_sec2_t *)_file;   /* VFD file struct          */
    herr_t ret_value = SUCCEED;                 /* Return value             */

    FUNC_ENTER_NOAPI_NOINIT

    HDassert(file);

    if(HDflock(file->fd, LOCK_UN) < 0) {
        if(ENOSYS == errno)
            HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, FAIL, "file locking disabled on this file system (use HDF5_USE_FILE_LOCKING environment variable to override)")
        else
            HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, FAIL, "unable to unlock file")
    } /* end if */

done:
    FUNC_LEAVE_NOAPI(ret_value)
} /* end H5FD_sec2_unlock() */