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119 lines
3.3 KiB
119 lines
3.3 KiB
/*
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This file is part of ethash.
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ethash is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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ethash is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with ethash. If not, see <http://www.gnu.org/licenses/>.
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*/
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/** @file io.c
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* @author Lefteris Karapetsas <lefteris@ethdev.com>
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* @date 2015
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*/
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#include "io.h"
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#include <string.h>
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#include <stdio.h>
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#include <errno.h>
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enum ethash_io_rc ethash_io_prepare(
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char const* dirname,
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ethash_h256_t const seedhash,
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FILE** output_file,
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uint64_t file_size,
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bool force_create
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)
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{
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char mutable_name[DAG_MUTABLE_NAME_MAX_SIZE];
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enum ethash_io_rc ret = ETHASH_IO_FAIL;
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// reset errno before io calls
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errno = 0;
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// assert directory exists
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if (!ethash_mkdir(dirname)) {
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ETHASH_CRITICAL("Could not create the ethash directory");
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goto end;
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}
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ethash_io_mutable_name(ETHASH_REVISION, &seedhash, mutable_name);
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char* tmpfile = ethash_io_create_filename(dirname, mutable_name, strlen(mutable_name));
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if (!tmpfile) {
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ETHASH_CRITICAL("Could not create the full DAG pathname");
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goto end;
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}
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FILE *f;
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if (!force_create) {
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// try to open the file
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f = ethash_fopen(tmpfile, "rb+");
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if (f) {
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size_t found_size;
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if (!ethash_file_size(f, &found_size)) {
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fclose(f);
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ETHASH_CRITICAL("Could not query size of DAG file: \"%s\"", tmpfile);
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goto free_memo;
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}
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if (file_size != found_size - ETHASH_DAG_MAGIC_NUM_SIZE) {
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fclose(f);
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ret = ETHASH_IO_MEMO_SIZE_MISMATCH;
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goto free_memo;
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}
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// compare the magic number, no need to care about endianess since it's local
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uint64_t magic_num;
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if (fread(&magic_num, ETHASH_DAG_MAGIC_NUM_SIZE, 1, f) != 1) {
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// I/O error
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fclose(f);
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ETHASH_CRITICAL("Could not read from DAG file: \"%s\"", tmpfile);
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ret = ETHASH_IO_MEMO_SIZE_MISMATCH;
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goto free_memo;
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}
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if (magic_num != ETHASH_DAG_MAGIC_NUM) {
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fclose(f);
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ret = ETHASH_IO_MEMO_SIZE_MISMATCH;
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goto free_memo;
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}
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ret = ETHASH_IO_MEMO_MATCH;
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goto set_file;
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}
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}
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// file does not exist, will need to be created
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f = ethash_fopen(tmpfile, "wb+");
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if (!f) {
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ETHASH_CRITICAL("Could not create DAG file: \"%s\"", tmpfile);
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goto free_memo;
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}
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// make sure it's of the proper size
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if (fseek(f, (long int)(file_size + ETHASH_DAG_MAGIC_NUM_SIZE - 1), SEEK_SET) != 0) {
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fclose(f);
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ETHASH_CRITICAL("Could not seek to the end of DAG file: \"%s\". Insufficient space?", tmpfile);
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goto free_memo;
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}
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if (fputc('\n', f) == EOF) {
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fclose(f);
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ETHASH_CRITICAL("Could not write in the end of DAG file: \"%s\". Insufficient space?", tmpfile);
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goto free_memo;
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}
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if (fflush(f) != 0) {
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fclose(f);
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ETHASH_CRITICAL("Could not flush at end of DAG file: \"%s\". Insufficient space?", tmpfile);
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goto free_memo;
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}
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ret = ETHASH_IO_MEMO_MISMATCH;
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goto set_file;
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ret = ETHASH_IO_MEMO_MATCH;
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set_file:
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*output_file = f;
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free_memo:
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free(tmpfile);
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end:
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return ret;
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}
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