static int write_at(git_indexer *idx, const void *data, git_off_t offset, size_t size)
{
git_file fd = idx->pack->mwf.fd;
size_t page_size;
size_t page_offset;
git_off_t page_start;
unsigned char *map_data;
git_map map;
int error;
assert(data && size);
if ((error = git__page_size(&page_size)) < 0)
return error;
/* the offset needs to be at the beginning of the a page boundary */
page_offset = offset % page_size;
page_start = offset - page_offset;
if ((error = p_mmap(&map, page_offset + size, GIT_PROT_WRITE, GIT_MAP_SHARED, fd, page_start)) < 0)
return error;
map_data = (unsigned char *)map.data;
memcpy(map_data + page_offset, data, size);
p_munmap(&map);
return 0;
}
static int parse_header(struct git_pack_header *hdr, struct git_pack_file *pack)
{
int error;
git_map map;
if ((error = p_mmap(&map, sizeof(*hdr), GIT_PROT_READ, GIT_MAP_SHARED, pack->mwf.fd, 0)) < 0)
return error;
memcpy(hdr, map.data, sizeof(*hdr));
p_munmap(&map);
/* Verify we recognize this pack file format. */
if (hdr->hdr_signature != ntohl(PACK_SIGNATURE)) {
giterr_set(GITERR_INDEXER, "Wrong pack signature");
return -1;
}
if (!pack_version_ok(hdr->hdr_version)) {
giterr_set(GITERR_INDEXER, "Wrong pack version");
return -1;
}
return 0;
}
void git_futils_mmap_free(git_map *out)
{
p_munmap(out);
}
