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/*
* Copyright (C) the libgit2 contributors. All rights reserved.
*
* This file is part of libgit2, distributed under the GNU GPL v2 with
* a Linking Exception. For full terms see the included COPYING file.
*/
#include "git2_util.h"
#include "map.h"
#include <errno.h>
#ifndef NO_MMAP
static DWORD get_page_size(void)
{
static DWORD page_size;
SYSTEM_INFO sys;
if (!page_size) {
GetSystemInfo(&sys);
page_size = sys.dwPageSize;
}
return page_size;
}
static DWORD get_allocation_granularity(void)
{
static DWORD granularity;
SYSTEM_INFO sys;
if (!granularity) {
GetSystemInfo(&sys);
granularity = sys.dwAllocationGranularity;
}
return granularity;
}
int git__page_size(size_t *page_size)
{
*page_size = get_page_size();
return 0;
}
int git__mmap_alignment(size_t *page_size)
{
*page_size = get_allocation_granularity();
return 0;
}
int p_mmap(git_map *out, size_t len, int prot, int flags, int fd, off64_t offset)
{
HANDLE fh = (HANDLE)_get_osfhandle(fd);
DWORD alignment = get_allocation_granularity();
DWORD fmap_prot = 0;
DWORD view_prot = 0;
DWORD off_low = 0;
DWORD off_hi = 0;
off64_t page_start;
off64_t page_offset;
GIT_MMAP_VALIDATE(out, len, prot, flags);
out->data = NULL;
out->len = 0;
out->fmh = NULL;
if (fh == INVALID_HANDLE_VALUE) {
errno = EBADF;
git_error_set(GIT_ERROR_OS, "failed to mmap. Invalid handle value");
return -1;
}
if (prot & GIT_PROT_WRITE)
fmap_prot |= PAGE_READWRITE;
else if (prot & GIT_PROT_READ)
fmap_prot |= PAGE_READONLY;
if (prot & GIT_PROT_WRITE)
view_prot |= FILE_MAP_WRITE;
if (prot & GIT_PROT_READ)
view_prot |= FILE_MAP_READ;
page_start = (offset / alignment) * alignment;
page_offset = offset - page_start;
if (page_offset != 0) { /* offset must be multiple of the allocation granularity */
errno = EINVAL;
git_error_set(GIT_ERROR_OS, "failed to mmap. Offset must be multiple of allocation granularity");
return -1;
}
out->fmh = CreateFileMapping(fh, NULL, fmap_prot, 0, 0, NULL);
if (!out->fmh || out->fmh == INVALID_HANDLE_VALUE) {
git_error_set(GIT_ERROR_OS, "failed to mmap. Invalid handle value");
out->fmh = NULL;
return -1;
}
off_low = (DWORD)(page_start);
off_hi = (DWORD)(page_start >> 32);
out->data = MapViewOfFile(out->fmh, view_prot, off_hi, off_low, len);
if (!out->data) {
git_error_set(GIT_ERROR_OS, "failed to mmap. No data written");
CloseHandle(out->fmh);
out->fmh = NULL;
return -1;
}
out->len = len;
return 0;
}
int p_munmap(git_map *map)
{
int error = 0;
GIT_ASSERT_ARG(map);
if (map->data) {
if (!UnmapViewOfFile(map->data)) {
git_error_set(GIT_ERROR_OS, "failed to munmap. Could not unmap view of file");
error = -1;
}
map->data = NULL;
}
if (map->fmh) {
if (!CloseHandle(map->fmh)) {
git_error_set(GIT_ERROR_OS, "failed to munmap. Could not close handle");
error = -1;
}
map->fmh = NULL;
}
return error;
}
#endif
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