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/*
This file is part of ethash.
ethash is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
ethash is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with ethash. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file io.c
* @author Lefteris Karapetsas <lefteris@ethdev.com>
* @date 2015
*/
#include "io.h"
#include <string.h>
#include <stdio.h>
enum ethash_io_rc ethash_io_prepare(
char const* dirname,
ethash_h256_t const seedhash,
FILE** output_file,
size_t file_size,
bool force_create
)
{
char mutable_name[DAG_MUTABLE_NAME_MAX_SIZE];
enum ethash_io_rc ret = ETHASH_IO_FAIL;
// assert directory exists
if (!ethash_mkdir(dirname)) {
goto end;
}
ethash_io_mutable_name(ETHASH_REVISION, &seedhash, mutable_name);
char* tmpfile = ethash_io_create_filename(dirname, mutable_name, strlen(mutable_name));
if (!tmpfile) {
goto end;
}
FILE *f;
if (!force_create) {
// try to open the file
f = ethash_fopen(tmpfile, "rb+");
if (f) {
size_t found_size;
if (!ethash_file_size(f, &found_size)) {
fclose(f);
goto free_memo;
}
if (file_size != found_size) {
fclose(f);
ret = ETHASH_IO_MEMO_SIZE_MISMATCH;
goto free_memo;
}
ret = ETHASH_IO_MEMO_MATCH;
goto set_file;
}
}
// file does not exist, will need to be created
f = ethash_fopen(tmpfile, "wb+");
if (!f) {
goto free_memo;
}
// make sure it's of the proper size
if (fseek(f, file_size - 1, SEEK_SET) != 0) {
fclose(f);
goto free_memo;
}
fputc('\n', f);
fflush(f);
ret = ETHASH_IO_MEMO_MISMATCH;
goto set_file;
ret = ETHASH_IO_MEMO_MATCH;
set_file:
*output_file = f;
free_memo:
free(tmpfile);
end:
return ret;
}