EXPORTED int gzuc_skip(struct gzuncat *gz, size_t len)
{
if (gzuc_member_eof(gz)) return -1;
while (len) {
unsigned char discard[16 * 1024];
size_t want = len;
if (want > sizeof(discard)) want = sizeof(discard);
ssize_t got = gzuc_read(gz, discard, want);
if (got == 0) return -1;
if (got < 0) return got;
len -= got;
}
return 0;
}
static int verify_chunk_checksums(struct backup *backup, struct backup_chunk *chunk,
struct gzuncat *gzuc, int verbose, FILE *out)
{
int r;
if (out && verbose)
fprintf(out, "checking chunk %d checksums...\n", chunk->id);
/* validate file-prior-to-this-chunk checksum */
if (out && verbose > 1)
fprintf(out, " checking file checksum...\n");
char file_sha1[2 * SHA1_DIGEST_LENGTH + 1];
sha1_file(backup->fd, backup->data_fname, chunk->offset, file_sha1);
r = strncmp(chunk->file_sha1, file_sha1, sizeof(file_sha1));
if (r) {
syslog(LOG_DEBUG, "%s: %s (chunk %d) file checksum mismatch: %s on disk, %s in index\n",
__func__, backup->data_fname, chunk->id, file_sha1, chunk->file_sha1);
if (out)
fprintf(out, "file checksum mismatch for chunk %d: %s on disk, %s in index\n",
chunk->id, file_sha1, chunk->file_sha1);
goto done;
}
/* validate data-within-this-chunk checksum */
// FIXME length and data_sha1 are set at backup_append_end.
// detect and correctly report case where this hasn't occurred.
if (out && verbose > 1)
fprintf(out, " checking data length\n");
char buf[8192]; /* FIXME whatever */
size_t len = 0;
SHA_CTX sha_ctx;
SHA1_Init(&sha_ctx);
gzuc_member_start_from(gzuc, chunk->offset);
while (!gzuc_member_eof(gzuc)) {
ssize_t n = gzuc_read(gzuc, buf, sizeof(buf));
if (n >= 0) {
SHA1_Update(&sha_ctx, buf, n);
len += n;
}
}
gzuc_member_end(gzuc, NULL);
if (len != chunk->length) {
syslog(LOG_DEBUG, "%s: %s (chunk %d) data length mismatch: "
SIZE_T_FMT " on disk,"
SIZE_T_FMT " in index\n",
__func__, backup->data_fname, chunk->id, len, chunk->length);
if (out)
fprintf(out, "data length mismatch for chunk %d: "
SIZE_T_FMT " on disk,"
SIZE_T_FMT " in index\n",
chunk->id, len, chunk->length);
r = -1;
goto done;
}
if (out && verbose > 1)
fprintf(out, " checking data checksum...\n");
unsigned char sha1_raw[SHA1_DIGEST_LENGTH];
char data_sha1[2 * SHA1_DIGEST_LENGTH + 1];
SHA1_Final(sha1_raw, &sha_ctx);
r = bin_to_hex(sha1_raw, SHA1_DIGEST_LENGTH, data_sha1, BH_LOWER);
assert(r == 2 * SHA1_DIGEST_LENGTH);
r = strncmp(chunk->data_sha1, data_sha1, sizeof(data_sha1));
if (r) {
syslog(LOG_DEBUG, "%s: %s (chunk %d) data checksum mismatch: %s on disk, %s in index\n",
__func__, backup->data_fname, chunk->id, data_sha1, chunk->data_sha1);
if (out)
fprintf(out, "data checksum mismatch for chunk %d: %s on disk, %s in index\n",
chunk->id, data_sha1, chunk->data_sha1);
goto done;
}
done:
syslog(LOG_DEBUG, "%s: checksum %s!\n", __func__, r ? "failed" : "passed");
if (out && verbose)
fprintf(out, "%s\n", r ? "error" : "ok");
return r;
}
