mirror of
https://git.proxmox.com/git/libgit2
synced 2026-01-10 12:06:17 +00:00
79ca2edcd4
In particular, the git__mmap() and git__munmap() routines provide the interface to platform specific memory-mapped file facilities. We provide implementations for unix and win32, which can be found in their own sub-directories. Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk> Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
126 lines
2.2 KiB
C
126 lines
2.2 KiB
C
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#include "map.h"
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#include <errno.h>
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static DWORD get_page_size(void)
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{
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static DWORD page_size;
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SYSTEM_INFO sys;
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if (!page_size) {
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GetSystemInfo(&sys);
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page_size = sys.dwAllocationGranularity;
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}
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return page_size;
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}
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int git__mmap(git_map *out, size_t len, int prot, int flags, int fd, off_t offset)
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{
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HANDLE fh = (HANDLE)_get_osfhandle(fd);
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DWORD page_size = get_page_size();
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DWORD fmap_prot = 0;
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DWORD view_prot = 0;
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DWORD off_low = 0;
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DWORD off_hi = 0;
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off_t page_start;
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off_t page_offset;
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assert((out != NULL) && (len > 0));
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if ((out == NULL) || (len == 0)) {
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errno = EINVAL;
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return GIT_ERROR;
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}
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out->data = NULL;
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out->len = 0;
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out->fmh = NULL;
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if (fh == INVALID_HANDLE_VALUE) {
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errno = EBADF;
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return GIT_ERROR;
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}
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if (prot & GIT_PROT_WRITE)
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fmap_prot |= PAGE_READWRITE;
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else if (prot & GIT_PROT_READ)
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fmap_prot |= PAGE_READONLY;
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else {
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errno = EINVAL;
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return GIT_ERROR;
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}
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if (prot & GIT_PROT_WRITE)
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view_prot |= FILE_MAP_WRITE;
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if (prot & GIT_PROT_READ)
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view_prot |= FILE_MAP_READ;
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if (flags & GIT_MAP_FIXED) {
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errno = EINVAL;
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return GIT_ERROR;
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}
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page_start = (offset / page_size) * page_size;
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page_offset = offset - page_start;
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if (page_offset != 0) { /* offset must be multiple of page size */
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errno = EINVAL;
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return GIT_ERROR;
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}
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out->fmh = CreateFileMapping(fh, NULL, fmap_prot, 0, 0, NULL);
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if (!out->fmh || out->fmh == INVALID_HANDLE_VALUE) {
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/* errno = ? */
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out->fmh = NULL;
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return GIT_ERROR;
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}
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off_low = (DWORD)(page_start);
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if (sizeof(off_t) > 4)
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off_hi = (DWORD)(page_start >> 32);
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out->data = MapViewOfFile(out->fmh, view_prot, off_hi, off_low, len);
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if (!out->data) {
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/* errno = ? */
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CloseHandle(out->fmh);
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out->fmh = NULL;
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return GIT_ERROR;
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}
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out->len = len;
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return GIT_SUCCESS;
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}
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int git__munmap(git_map *map)
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{
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assert(map != NULL);
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if (!map)
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return GIT_ERROR;
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if (map->data) {
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if (!UnmapViewOfFile(map->data)) {
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/* errno = ? */
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CloseHandle(map->fmh);
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map->data = NULL;
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map->fmh = NULL;
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return GIT_ERROR;
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}
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map->data = NULL;
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}
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if (map->fmh) {
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if (!CloseHandle(map->fmh)) {
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/* errno = ? */
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map->fmh = NULL;
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return GIT_ERROR;
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}
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map->fmh = NULL;
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}
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return GIT_SUCCESS;
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}
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