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-rw-r--r--src/backup.c54
-rw-r--r--src/file.c17
-rw-r--r--src/file.h3
-rw-r--r--src/restore.c60
4 files changed, 69 insertions, 65 deletions
diff --git a/src/backup.c b/src/backup.c
index 15628b8..186cff0 100644
--- a/src/backup.c
+++ b/src/backup.c
@@ -38,8 +38,6 @@ static int check_files(const options_t *const opts,
const resources_t *const res);
static int allocate_buffers(const options_t *const opts, size_t out_buffer_size,
resources_t *const res);
-static int read_sector(FILE *const file, char *const buffer,
- uint32_t buffer_size, uint32_t sector_size);
static int write_out_buffer(const char *const buffer, size_t size,
FILE *const file);
@@ -94,26 +92,6 @@ allocate_buffers(const options_t *const opts, size_t out_buffer_size,
}
static int
-read_sector(FILE *const file, char *const buffer, uint32_t buffer_size,
- uint32_t sector_size)
-{
- const size_t bytes_read = fread(buffer, 1U, buffer_size, file);
-
- if (ferror(file)) {
- print_error("cannot read from input file: %s", strerror(errno));
- return 1;
- } else if ((bytes_read % sector_size) != 0) {
- print_error("data read from input file is not multiple of sector size");
- return 1;
- } else if (bytes_read != buffer_size) {
- print_error("cannot read enough data from input file");
- return 1;
- }
-
- return 0;
-}
-
-static int
write_out_buffer(const char *const buffer, size_t size, FILE *const file)
{
const size_t bytes_written = fwrite(buffer, 1U, size, file);
@@ -145,29 +123,33 @@ backup(const options_t *const opts, resources_t *const res)
size_t out_buffer_index = 0;
uint64_t input_file_offset = 0;
- while (!feof(res->in_file)) {
- /* Read the sectors from the input file to the buffer */
- if (read_sector(res->in_file, res->in_buffer, opts->buffer_size,
- opts->sector_size) != 0) {
+ for (;;) {
+ /* Read the sectors from the input and reference files into the buffers
+ */
+ const size_t in_sectors_read = file_read_sectors(
+ res->in_file, res->in_buffer, opts->buffer_size, opts->sector_size);
+ const size_t ref_sectors_read =
+ file_read_sectors(res->ref_file, res->ref_buffer, opts->buffer_size,
+ opts->sector_size);
+
+ if ((in_sectors_read == 0) || (ref_sectors_read == 0)) {
+ break;
+ } else if (in_sectors_read != ref_sectors_read) {
+ print_error(
+ "cannot read equal amount of sectors from the input files");
return 1;
}
- /* Read sectors from the reference file to the buffer */
- if (read_sector(res->ref_file, res->ref_buffer, opts->buffer_size,
- opts->sector_size) != 0) {
- return 1;
- }
+ /* Process the sectors in the buffers */
+ for (size_t sector = 0; sector < in_sectors_read; ++sector) {
+ const size_t buffer_offset = sector * opts->sector_size;
- /* Process sectors in the buffer */
- for (size_t buffer_offset = 0; buffer_offset < opts->buffer_size;
- buffer_offset += opts->sector_size) {
if (memcmp(res->in_buffer + buffer_offset,
res->ref_buffer + buffer_offset,
opts->sector_size) != 0) {
/* Backup the changed sector */
if (out_buffer_index >= out_buffer_size) {
- /* The output buffer is full. Write it to the output file.
- */
+ /* The output buffer is full. Write it to the output file */
if (write_out_buffer(res->out_buffer, out_buffer_index,
res->out_file) != 1) {
return 1;
diff --git a/src/file.c b/src/file.c
index 634bb3b..57a847a 100644
--- a/src/file.c
+++ b/src/file.c
@@ -48,3 +48,20 @@ file_size(FILE *const file)
return size;
}
+
+size_t
+file_read_sectors(FILE *const file, char *const buffer, uint32_t buffer_size,
+ uint32_t sector_size)
+{
+ const size_t bytes_read = fread(buffer, 1U, buffer_size, file);
+
+ if (ferror(file)) {
+ print_error("cannot read from file: %s", strerror(errno));
+ return 0;
+ } else if ((bytes_read % sector_size) != 0) {
+ print_error("data read from input file is not multiple of sector size");
+ return 0;
+ } else {
+ return (bytes_read / sector_size);
+ }
+}
diff --git a/src/file.h b/src/file.h
index 7c77b45..886098b 100644
--- a/src/file.h
+++ b/src/file.h
@@ -27,8 +27,11 @@
#ifndef FILE_H
#define FILE_H
+#include <stdint.h>
#include <stdio.h>
long file_size(FILE *const file);
+size_t file_read_sectors(FILE *const file, char *const buffer,
+ uint32_t buffer_size, uint32_t sector_size);
#endif /* FILE_H */
diff --git a/src/restore.c b/src/restore.c
index 1c2beae..6318766 100644
--- a/src/restore.c
+++ b/src/restore.c
@@ -63,7 +63,8 @@ is_reference_file_valid(resources_t *const res, uint32_t sector_size)
return 1;
}
- uint64_t prev_out_offset;
+ uint64_t prev_out_offset = 0;
+ bool is_first_reading = true;
/* Scan the reference file and check */
for (;;) {
@@ -78,18 +79,19 @@ is_reference_file_valid(resources_t *const res, uint32_t sector_size)
} else if ((ref_read != 1U) || ferror(res->ref_file)) {
print_error("cannot read from reference file: %s", strerror(errno));
return false;
- } else if (((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");
+ } 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->ref_file, sector_size, SEEK_CUR) != 0) {
print_error("cannot seek in reference file: %s", strerror(errno));
return false;
}
+ is_first_reading = false;
prev_out_offset = out_offset;
}
@@ -123,9 +125,9 @@ restore(const options_t *const opts, resources_t *const res)
/* 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;
+ const size_t ref_sector_size = sizeof(uint64_t) + opts->sector_size;
+ const size_t ref_buffer_sector_count = opts->buffer_size / ref_sector_size;
+ const size_t ref_buffer_size = ref_buffer_sector_count * ref_sector_size;
if ((res->ref_buffer = (char *)malloc(ref_buffer_size)) == NULL) {
print_error("cannot allocate buffer for reference file data");
@@ -134,34 +136,34 @@ restore(const options_t *const opts, resources_t *const res)
/* Restore data from the differential image */
for (;;) {
- uint64_t out_offset;
/* 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);
+ const size_t ref_sectors_read = file_read_sectors(
+ res->ref_file, res->ref_buffer, ref_buffer_size, ref_sector_size);
- if (feof(res->ref_file)) {
+ if (ref_sectors_read == 0) {
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));
+ char *ref_buffer = 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;
- }
+ for (size_t s = 0; s < ref_sectors_read; ++s) {
+ const uint64_t out_offset = le64toh(*((uint64_t *)ref_buffer));
+ ref_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;
+ }
- /* 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);
+ const size_t out_written =
+ fwrite(ref_buffer, opts->sector_size, 1U, res->out_file);
+ ref_buffer += opts->sector_size;
- if (out_written != 1U) {
- print_error("cannot write to output file: %s", strerror(errno));
- return 1;
+ if (out_written != 1U) {
+ print_error("cannot write to output file: %s", strerror(errno));
+ return 1;
+ }
}
}
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