vm_mmap_linux32.c

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/*
//
//                  INTEL CORPORATION PROPRIETARY INFORMATION
//     This software is supplied under the terms of a license agreement or
//     nondisclosure agreement with Intel Corporation and may not be copied
//     or disclosed except in accordance with the terms of that agreement.
//       Copyright(c) 2003-2005 Intel Corporation. All Rights Reserved.
//
*/

#ifdef LINUX32

#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include "vm_mmap.h"


/* Set the mmap handle an invalid value */
void vm_mmap_set_invalid(vm_mmap *handle)
{
    /* check error(s) */
    if (NULL == handle)
        return;

    handle->fd= -1;
    handle->address = NULL;
    handle->fAccessAttr = 0;

} /* void vm_mmap_set_invalid(vm_mmap *handle) */

/* Verify if the mmap handle is valid */
int vm_mmap_is_valid(vm_mmap *handle)
{
    /* check error(s) */
    if (NULL == handle)
        return 0;

    return (-1 != handle->fd);

} /* int vm_mmap_is_valid(vm_mmap *handle) */

/* Map a file into system meory, return size of the mapped file */
vm_sizet vm_mmap_create(vm_mmap *handle, vm_char *file, int fileAccessAttr)
{
    size_t sizet;

    /* check error(s) */
    if (NULL == handle)
        return 0;

    handle->address = NULL;
    handle->sizet = 0;

    if(FLAG_ATTRIBUTE_READ & fileAccessAttr)
        handle->fd = open(file, O_RDONLY);
    else
        handle->fd = open(file, O_RDWR | O_CREAT);

    if (-1 == handle->fd)
        return 0;

    sizet = lseek(handle->fd, 0, SEEK_END);
    lseek(handle->fd, 0, SEEK_SET);

    return sizet;

} /* vm_sizet vm_mmap_create(vm_mmap *handle, vm_char *file, int fileAccessAttr) */

/* Obtain a view of the mapped file, return the adjusted offset & size */
void *vm_mmap_set_view(vm_mmap *handle, vm_sizet *offset, vm_sizet *sizet)
{
    vm_sizet pagesize = getpagesize();
    vm_sizet edge;

    /* check error(s) */
    if (NULL == handle)
        return NULL;

    if (handle->address)
        munmap(handle->address,handle->sizet);

    edge = (*sizet) + (*offset);
    (*offset) = ((vm_sizet)((*offset) / pagesize)) * pagesize;
    handle->sizet = (*sizet) = edge - (*offset);
    handle->address = mmap(0,
                           *sizet,
                           PROT_READ,
                           MAP_SHARED,
                           handle->fd,
                           *offset);

    return handle->address;

} /* void *vm_mmap_set_view(vm_mmap *handle, vm_sizet *offset, vm_sizet *sizet) */

/* Remove the mmap */
void vm_mmap_close(vm_mmap *handle)
{
    /* check error(s) */
    if (NULL == handle)
        return;

    if (handle->address)
    {
        munmap(handle->address, handle->sizet);
        handle->address = NULL;
    }

    if (-1 != handle->fd)
    {
        close(handle->fd);
        handle->fd= -1;
    }

} /* void vm_mmap_close(vm_mmap *handle) */

vm_var32 vm_mmap_get_page_size(void)
{
    return getpagesize();

} /* vm_var32 vm_mmap_get_page_size(void) */

vm_var32 vm_mmap_get_alloc_granularity(void)
{
    return 16 * getpagesize();

} /* vm_var32 vm_mmap_get_alloc_granularity(void) */

void vm_mmap_unmap(vm_mmap *handle)
{
    /* check error(s) */
    if (NULL == handle)
        return;

    if (handle->address)
    {
        munmap(handle->address, handle->sizet);
        handle->address = NULL;
    }

} /* void vm_mmap_unmap(vm_mmap *handle) */

#endif /* LINUX32 */