diff options
Diffstat (limited to 'main.c')
| -rw-r--r-- | main.c | 376 |
1 files changed, 0 insertions, 376 deletions
@@ -1,376 +0,0 @@ -#include <endian.h> -#include <errno.h> -#include <inttypes.h> -#include <stdint.h> -#include <stdio.h> -#include <stdlib.h> -#include <string.h> - -#include "file.h" -#include "options.h" -#include "print.h" -#include "resources.h" - -/* This header file is automatically generated at build time from the Makefile - */ -#include "program_info.h" - -void -usage(int exit_code) -{ - printf("Usage: %s [-s SECTOR_SIZE] [-b BUFFER_SIZE] [INFILE] REFFILE " - "OUTFILE\n", - PROGRAM_NAME_STR); - exit(exit_code); -} - -void -clean_exit(resources_t *const res, int exit_code) -{ - resources_free(res); - exit(exit_code); -} - -int -open_files(const options_t *const opts, resources_t *const res, - bool is_action_backup) -{ - /* Open the input file */ - if ((opts->in_file_path != NULL) && - ((res->in_file = fopen(opts->in_file_path, "r")) == NULL)) { - print_error("cannot open input file: %s", strerror(errno)); - return 1; - } - - /* Open the reference file */ - if ((res->ref_file = fopen(opts->ref_file_path, "r")) == NULL) { - print_error("cannot open reference file: %s", strerror(errno)); - return 1; - } - - /* Open the output file - * - * When restoring, the file must be opened for writing and not - * truncated - */ - char out_mode[] = "r+"; - - if (is_action_backup) { - /* When backing up, the output file is truncated to hold the - * new data - */ - out_mode[0] = 'w'; - out_mode[1] = '\0'; - } - - if ((res->out_file = fopen(opts->out_file_path, out_mode)) == NULL) { - print_error("cannot open output file: %s", strerror(errno)); - return 1; - } - - return 0; -} - -bool -is_reference_file_valid(resources_t *const res, uint32_t sector_size) -{ - const long ref_size = file_size(res->ref_file); - - if (ref_size < 0) { - print_error("cannot get size of reference file: %s", strerror(errno)); - return false; - } else if (ref_size == 0) { - print_error("reference file is empty"); - return false; - } else if ((ref_size % (sizeof(uint64_t) + sector_size)) != 0) { - /* The reference file must hold equally sized sectors and the - * offset of each of them - */ - print_error( - "reference file has size that cannot contain valid diff data"); - return false; - } - - const long out_size = file_size(res->out_file); - - if (out_size < 0) { - print_error("cannot get size of output file: %s", strerror(errno)); - return 1; - } - - uint64_t ref_offset = 0; - uint64_t prev_out_offset; - - /* Scan the reference file and check */ - for (;;) { - uint64_t out_offset; - /* Read the next offset */ - const size_t ref_read = - fread(&out_offset, sizeof(out_offset), 1U, res->ref_file); - out_offset = le64toh(out_offset); - - if (feof(res->ref_file)) { - break; - } else if ((ref_read != 1U) || ferror(res->ref_file)) { - print_error("cannot read from reference file: %s", strerror(errno)); - return false; - } else if (((ref_offset != 0) && (out_offset <= prev_out_offset)) || - ((out_offset + sector_size) > out_size)) { - /* The offset must be higher than the previous one and it - * must point into the file - */ - print_error("reference file is not valid"); - return false; - } else if (fseek(res->ref_file, sector_size, SEEK_CUR) != 0) { - print_error("cannot seek in reference file: %s", strerror(errno)); - return false; - } - - prev_out_offset = out_offset; - } - - if (ftell(res->ref_file) != ref_size) { - /* The reference file must be read completely */ - print_error("reference file is not valid"); - return false; - } else if (fseek(res->ref_file, 0L, SEEK_SET) != 0) { - /* The file must be prepared for the restoring */ - print_error("cannot seek in reference file: %s", strerror(errno)); - return false; - } - - return true; -} - -int -diff_backup(const options_t *const opts, resources_t *const res) -{ - const long in_size = file_size(res->in_file); - - if (in_size < 0) { - print_error("cannot get size of input file: %s", strerror(errno)); - return 1; - } - - const long ref_size = file_size(res->ref_file); - - if (ref_size < 0) { - print_error("cannot get size of reference file: %s", strerror(errno)); - return 1; - } - - /* Check sizes of the input file and the reference file */ - if (in_size != ref_size) { - print_error("input file and reference file differ in size"); - return 1; - } else if ((in_size % opts->sector_size) != 0) { - print_error( - "size of input file and reference file is not multiple of" PRIu32, - opts->sector_size); - return 1; - } - - /* Allocate the buffers */ - /* The output buffer contains also the offsets */ - const size_t out_buffer_size = - ((opts->buffer_size / opts->sector_size) * sizeof(uint64_t)) + - opts->buffer_size; - - if ((res->in_buffer = (char *)malloc(opts->buffer_size)) == NULL) { - print_error("cannot allocate buffer for input file data"); - return 1; - } else if ((res->ref_buffer = (char *)malloc(opts->buffer_size)) == NULL) { - print_error("cannot allocate buffer for reference file data"); - return 1; - } else if ((res->out_buffer = (char *)malloc(out_buffer_size)) == NULL) { - print_error("cannot allocate buffer for output file data"); - return 1; - } - - size_t out_buffer_index = 0; - uint64_t offset = 0; - - for (;;) { - /* Read the sectors from the input file to the buffer */ - const size_t in_read = - fread(res->in_buffer, 1U, opts->buffer_size, res->in_file); - - if ((in_read % opts->sector_size) != 0) { - print_error( - "data read from input file is not multiple of sector size"); - return 1; - } else if (ferror(res->in_file)) { - print_error("cannot read from input file: %s", strerror(errno)); - return 1; - } - - /* Read sectors from the reference file to the buffer */ - const size_t ref_read = - fread(res->ref_buffer, 1U, opts->buffer_size, res->ref_file); - - if ((ref_read % opts->sector_size) != 0) { - print_error( - "data read from reference file is not multiple of sector size"); - return 1; - } else if (ferror(res->ref_file)) { - print_error("%s", strerror(errno)); - return 1; - } - - if (in_read != ref_read) { - print_error( - "data read from input file and reference file differ in size"); - return 1; - } - - /* Process sectors in the buffer */ - for (size_t i = 0; i < in_read; i += opts->sector_size) { - /* Compare the sectors */ - int changed = 0; - const size_t j_end = i + opts->sector_size; - for (size_t j = i; j < j_end; ++j) { - if (res->in_buffer[j] != res->ref_buffer[j]) { - changed = 1; - break; - } - } - - if (changed) { - /* Write changed sector */ - if (out_buffer_index >= out_buffer_size) { - /* The output buffer is full. Write it to the - * output file. - */ - const size_t x = fwrite(res->out_buffer, 1U, - out_buffer_index, res->out_file); - - if (x != out_buffer_index) { - print_error("cannot write to output file: %s", - strerror(errno)); - return 1; - } - - out_buffer_index = 0; - } - - const uint64_t o = htole64(offset); - - memcpy(res->out_buffer + out_buffer_index, (void *)&o, - sizeof(o)); - memcpy(res->out_buffer + out_buffer_index, &(res->in_buffer[i]), - opts->sector_size); - out_buffer_index += sizeof(o) + opts->sector_size; - } - - offset += opts->sector_size; - } - - if (feof(res->in_file)) { - break; - } - } - - /* Write out the output buffer */ - if (out_buffer_index >= 0) { - const size_t x = - fwrite(res->out_buffer, 1U, out_buffer_index, res->out_file); - - if (x != out_buffer_index) { - print_error("cannot write to output file: %s", strerror(errno)); - return 1; - } - } - - return 0; -} - -int -diff_restore(const options_t *const opts, resources_t *const res) -{ - /* Check validity of the reference file */ - if (!is_reference_file_valid(res, opts->sector_size)) { - return 1; - } - - const long ref_size = file_size(res->ref_file); - - if (ref_size < 0) { - print_error("cannot get size of reference file: %s", strerror(errno)); - return 1; - } - - /* Allocate the buffer for data from the reference file */ - /* The reference buffer contains also the offsets */ - const size_t ref_buffer_size = - ((opts->buffer_size / opts->sector_size) * sizeof(uint64_t)) + - opts->buffer_size; - - if ((res->ref_buffer = (char *)malloc(ref_buffer_size)) == NULL) { - print_error("cannot allocate buffer for reference file data"); - return 1; - } - - /* Restore data from the differential image */ - uint64_t out_offset; - - for (;;) { - /* Read data of the offset and the next sector */ - const size_t ref_read = - fread(res->ref_buffer, ref_buffer_size, 1U, res->ref_file); - - if (feof(res->ref_file)) { - break; - } else if ((ref_read != 1U) || ferror(res->ref_file)) { - print_error("cannot read from reference file: %s", strerror(errno)); - return 1; - } - - /* Get offset */ - out_offset = le64toh(*((uint64_t *)res->ref_buffer)); - - if (fseek(res->out_file, out_offset, SEEK_SET) != 0) { - print_error("cannot seek in output file: %s", strerror(errno)); - return 1; - } - - /* Write the sector data to the output file */ - const size_t out_written = fwrite(res->ref_buffer + sizeof(out_offset), - opts->sector_size, 1U, res->out_file); - - if (out_written != 1U) { - print_error("cannot write to output file: %s", strerror(errno)); - return 1; - } - } - - /* The reference file must be read completely */ - if (ftell(res->ref_file) != ref_size) { - print_error("reference file is not valid"); - return 1; - } - - return 0; -} - -int -main(int argc, char **argv) -{ - options_t opts; - - if (options_parse(argc, argv, &opts) || opts.help) { - usage(1); - } - - const bool is_action_backup = (opts.in_file_path != NULL); - resources_t res; - - resources_init(&res); - - if (open_files(&opts, &res, is_action_backup) != 0) { - clean_exit(&res, 1); - } else if (is_action_backup) { - clean_exit(&res, diff_backup(&opts, &res)); - } else { - clean_exit(&res, diff_restore(&opts, &res)); - } -} |