1 files changed, 56 insertions, 0 deletions
diff --git a/lib/comp/compressor.c b/lib/comp/compressor.c
index 42ebd8b..3b473a3 100644
--- a/lib/comp/compressor.c
+++ b/lib/comp/compressor.c
@@ -1,7 +1,9 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
 #include <string.h>
+#include <stdio.h>
 
 #include "internal.h"
+#include "util.h"
 
 typedef compressor_t *(*compressor_fun_t)(bool compress, size_t block_size);
 
@@ -15,8 +17,62 @@ static compressor_fun_t compressors[SQFS_COMP_MAX + 1] = {
 #ifdef WITH_LZO
 	[SQFS_COMP_LZO] = create_lzo_compressor,
 #endif
+#ifdef WITH_LZ4
+	[SQFS_COMP_LZ4] = create_lz4_compressor,
+#endif
 };
 
+int generic_write_options(int fd, const void *data, size_t size)
+{
+	uint8_t buffer[size + 2];
+	ssize_t ret;
+
+	*((uint16_t *)buffer) = htole16(0x8000 | size);
+	memcpy(buffer + 2, data, size);
+
+	ret = write_retry(fd, buffer, sizeof(buffer));
+
+	if (ret < 0) {
+		perror("writing compressor options");
+		return -1;
+	}
+
+	if ((size_t)ret < sizeof(buffer)) {
+		fputs("writing compressor options: truncated write\n", stderr);
+		return -1;
+	}
+
+	return ret;
+}
+
+int generic_read_options(int fd, void *data, size_t size)
+{
+	uint8_t buffer[size + 2];
+	ssize_t ret;
+
+	ret = read_retry(fd, buffer, sizeof(buffer));
+
+	if (ret < 0) {
+		perror("reading compressor options");
+		return -1;
+	}
+
+	if ((size_t)ret < sizeof(buffer)) {
+		fputs("reading compressor options: unexpected end of file\n",
+		      stderr);
+		return -1;
+	}
+
+	if (le16toh(*((uint16_t *)buffer)) != (0x8000 | size)) {
+		fputs("reading compressor options: invalid meta data header\n",
+		      stderr);
+		return -1;
+	}
+
+	memcpy(data, buffer + 2, size);
+	return 0;
+}
+
 bool compressor_exists(E_SQFS_COMPRESSOR id)
 {
 	if (id < SQFS_COMP_MIN || id > SQFS_COMP_MAX)