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/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
* compare_file.c
*
* Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
*/
#include "difftool.h"
int compare_files(file_info_t *a, file_info_t *b, const char *path)
{
uint64_t offset, size, diff;
int ret = 0, afd, bfd;
void *aptr, *bptr;
if (a->size != b->size)
return 1;
if (pushd(first_path))
return -1;
afd = open(path, O_RDONLY);
if (afd < 0) {
fprintf(stderr, "%s/%s: %s\n", first_path, path,
strerror(errno));
return -1;
}
if (popd())
goto fail_afd;
if (pushd(second_path))
goto fail_afd;
bfd = open(path, O_RDONLY);
if (bfd < 0) {
fprintf(stderr, "%s/%s: %s\n", second_path, path,
strerror(errno));
goto fail_afd;
}
if (popd())
goto fail_bfd;
size = a->size;
for (offset = 0; offset < size; offset += diff) {
diff = size - offset;
if (diff > MAX_WINDOW_SIZE)
diff = MAX_WINDOW_SIZE;
aptr = mmap(NULL, diff, PROT_READ, MAP_SHARED, afd, offset);
if (aptr == MAP_FAILED) {
fprintf(stderr, "mmap %s/%s: %s\n", first_path, path,
strerror(errno));
goto fail_bfd;
}
bptr = mmap(NULL, diff, PROT_READ, MAP_SHARED, bfd, offset);
if (bptr == MAP_FAILED) {
fprintf(stderr, "mmap %s/%s: %s\n", second_path, path,
strerror(errno));
goto fail_bfd;
}
ret = memcmp(aptr, bptr, diff);
munmap(aptr, diff);
munmap(bptr, diff);
if (ret != 0)
break;
}
close(afd);
close(bfd);
return ret;
fail_bfd:
close(bfd);
fail_afd:
close(afd);
return -1;
}
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