+#else
+ log_error("Cannot decompress file. Compiled without XZ support.");
+ return -EPROTONOSUPPORT;
+#endif
+}
+
+int decompress_stream_lz4(int fdf, int fdt, off_t max_bytes) {
+
+#ifdef HAVE_LZ4
+ _cleanup_free_ char *buf = NULL, *out = NULL;
+ size_t buf_size = 0;
+ LZ4_streamDecode_t lz4_data = {};
+ le32_t header;
+ size_t total_in = sizeof(header), total_out = 0;
+
+ assert(fdf >= 0);
+ assert(fdt >= 0);
+
+ out = malloc(4*LZ4_BUFSIZE);
+ if (!out)
+ return log_oom();
+
+ for (;;) {
+ ssize_t n, m;
+ int r;
+
+ n = read(fdf, &header, sizeof(header));
+ if (n < 0)
+ return -errno;
+ if (n != sizeof(header))
+ return errno ? -errno : -EIO;
+
+ m = le32toh(header);
+ if (m == 0)
+ break;
+
+ /* We refuse to use a bigger decompression buffer than
+ * the one used for compression by 4 times. This means
+ * that compression buffer size can be enlarged 4
+ * times. This can be changed, but old binaries might
+ * not accept buffers compressed by newer binaries then.
+ */
+ if (m > LZ4_COMPRESSBOUND(LZ4_BUFSIZE * 4)) {
+ log_error("Compressed stream block too big: %zd bytes", m);
+ return -EBADMSG;
+ }
+
+ total_in += sizeof(header) + m;
+
+ if (!GREEDY_REALLOC(buf, buf_size, m))
+ return log_oom();
+
+ errno = 0;
+ n = loop_read(fdf, buf, m, false);
+ if (n < 0)
+ return n;
+ if (n != m)
+ return errno ? -errno : -EIO;
+
+ r = LZ4_decompress_safe_continue(&lz4_data, buf, out, m, 4*LZ4_BUFSIZE);
+ if (r <= 0)
+ log_error("LZ4 decompression failed.");
+
+ total_out += r;
+
+ if (max_bytes != -1 && total_out > (size_t) max_bytes) {
+ log_debug("Decompressed stream longer than %zd bytes", max_bytes);
+ return -EFBIG;
+ }
+
+ errno = 0;
+ n = loop_write(fdt, out, r, false);
+ if (n < 0)
+ return n;
+ if (n != r)
+ return errno ? -errno : -EIO;
+ }
+
+ log_debug("LZ4 decompression finished (%zu -> %zu bytes, %.1f%%)",
+ total_in, total_out,
+ (double) total_out / total_in * 100);
+
+ return 0;
+#else
+ log_error("Cannot decompress file. Compiled without LZ4 support.");
+ return -EPROTONOSUPPORT;
+#endif
+}
+
+int decompress_stream(const char *filename, int fdf, int fdt, off_t max_bytes) {
+
+ if (endswith(filename, ".lz4"))
+ return decompress_stream_lz4(fdf, fdt, max_bytes);
+ else if (endswith(filename, ".xz"))
+ return decompress_stream_xz(fdf, fdt, max_bytes);
+ else
+ return -EPROTONOSUPPORT;