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/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
* compare_files.c
*
* Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
*/
#include "sqfsdiff.h"
static unsigned char old_buf[MAX_WINDOW_SIZE];
static unsigned char new_buf[MAX_WINDOW_SIZE];
static int open_file(int dirfd, const char *prefix, const char *path)
{
int fd = openat(dirfd, path, O_RDONLY);
if (fd < 0) {
fprintf(stderr, "open %s/%s: %s\n",
prefix, path, strerror(errno));
}
return fd;
}
static int read_blob(const char *prefix, const char *path, bool is_dir,
int fd, data_reader_t *rd, file_info_t *fi, void *buffer,
off_t offset, size_t size)
{
ssize_t ret;
if (is_dir) {
ret = read_data_at(path, offset, fd, buffer, size);
} else {
ret = data_reader_read(rd, fi, offset, buffer, size);
ret = (ret < 0 || (size_t)ret < size) ? -1 : 0;
}
if (ret) {
fprintf(stderr, "Failed to read %s from %s\n",
path, prefix);
return -1;
}
return 0;
}
int compare_files(sqfsdiff_t *sd, file_info_t *old, file_info_t *new,
const char *path)
{
int old_fd = -1, new_fd = -1, status = 0, ret;
uint64_t offset, diff;
if (old->size != new->size)
goto out_different;
if (sd->compare_flags & COMPARE_NO_CONTENTS)
return 0;
if (sd->old_is_dir) {
old_fd = open_file(sd->old_fd, sd->old_path, path);
if (old_fd < 0)
goto fail;
}
if (sd->new_is_dir) {
new_fd = open_file(sd->new_fd, sd->new_path, path);
if (new_fd < 0)
goto fail;
}
for (offset = 0; offset < old->size; offset += diff) {
diff = old->size - offset;
if (diff > MAX_WINDOW_SIZE)
diff = MAX_WINDOW_SIZE;
ret = read_blob(sd->old_path, path, sd->old_is_dir, old_fd,
sd->sqfs_old.data, old, old_buf, offset, diff);
if (ret)
goto fail;
ret = read_blob(sd->new_path, path, sd->new_is_dir, new_fd,
sd->sqfs_new.data, new, new_buf, offset, diff);
if (ret)
goto fail;
if (memcmp(old_buf, new_buf, diff) != 0)
goto out_different;
}
out:
if (old_fd >= 0)
close(old_fd);
if (new_fd >= 0)
close(new_fd);
return status;
fail:
status = -1;
goto out;
out_different:
if (sd->compare_flags & COMPARE_EXTRACT_FILES) {
if (extract_files(sd, old, new, path))
goto fail;
}
status = 1;
goto out;
}
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