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/* Copyright 2021 Ján Sučan <jan@jansucan.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "restore.h"
#include "file.h"
#include "print.h"
#include <errno.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static bool
is_input_file_valid(const resources_restore_t *const res, uint32_t sector_size)
{
bool in_size_ok = false;
const size_t in_size = file_size(res->in_file, &in_size_ok);
if (!in_size_ok) {
print_error("cannot get size of input file: %s", strerror(errno));
return false;
} else if (in_size == 0) {
print_error("input file is empty");
return false;
} else if ((in_size % (sizeof(uint64_t) + sector_size)) != 0) {
/* The input file must hold equally sized sectors and the
* offset of each of them
*/
print_error("input file has size that cannot contain valid diff data");
return false;
}
bool out_size_ok = false;
const size_t out_size = file_size(res->out_file, &out_size_ok);
if (!out_size_ok) {
print_error("cannot get size of output file: %s", strerror(errno));
return 1;
}
uint64_t prev_out_offset = 0;
bool is_first_reading = true;
/* Scan the input file and check */
for (;;) {
uint64_t out_offset;
/* Read the next offset */
const size_t in_read =
fread(&out_offset, sizeof(out_offset), 1U, res->in_file);
out_offset = le64toh(out_offset);
if (feof(res->in_file)) {
break;
} else if ((in_read != 1U) || ferror(res->in_file)) {
print_error("cannot read from input file: %s", strerror(errno));
return false;
} else if (!is_first_reading && (out_offset <= prev_out_offset)) {
print_error("a sector offset points behind the previous offset");
return false;
} else if ((out_offset + sector_size) > out_size) {
print_error(
"a sector offset points past the end of the output file");
return false;
} else if (fseek(res->in_file, sector_size, SEEK_CUR) != 0) {
print_error("cannot seek in input file: %s", strerror(errno));
return false;
}
is_first_reading = false;
prev_out_offset = out_offset;
}
bool pos_ok = false;
const size_t pos = file_tell(res->in_file, &pos_ok);
if (!pos_ok) {
print_error("cannot get position in the input file");
return false;
} else if (pos != in_size) {
/* The input file must be read completely */
print_error("input file is not valid");
return false;
} else if (fseek(res->in_file, 0L, SEEK_SET) != 0) {
/* The file must be prepared for the restoring */
print_error("cannot seek in input file: %s", strerror(errno));
return false;
}
return true;
}
int
restore(const options_restore_t *const opts,
const resources_restore_t *const res)
{
/* Check validity of the input file */
if (!is_input_file_valid(res, opts->sector_size)) {
return 1;
}
bool in_size_ok = false;
const size_t in_size = file_size(res->in_file, &in_size_ok);
if (!in_size_ok) {
print_error("cannot get size of input file: %s", strerror(errno));
return 1;
}
/* Restore data from the differential image */
for (;;) {
/* Read data of the offset and the next sector */
const size_t in_sectors_read =
file_read_sectors(res->in_file, res->in_buffer, res->in_buffer_size,
res->in_sector_size);
if (in_sectors_read == 0) {
break;
}
char *in_buffer = res->in_buffer;
for (size_t s = 0; s < in_sectors_read; ++s) {
const uint64_t out_offset = le64toh(*((uint64_t *)in_buffer));
in_buffer += sizeof(uint64_t);
if (fseek(res->out_file, out_offset, SEEK_SET) != 0) {
print_error("cannot seek in output file: %s", strerror(errno));
return 1;
}
const size_t out_written =
fwrite(in_buffer, opts->sector_size, 1U, res->out_file);
in_buffer += opts->sector_size;
if (out_written != 1U) {
print_error("cannot write to output file: %s", strerror(errno));
return 1;
}
}
}
/* The input file must be read completely */
bool pos_ok = false;
const size_t pos = file_tell(res->in_file, &pos_ok);
if (!pos_ok) {
print_error("cannot get position in the input file");
return 1;
} else if (pos != in_size) {
print_error("input file is not valid");
return 1;
}
return 0;
}
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