1 files changed, 96 insertions, 0 deletions
diff --git a/sys/cddl/boot/zfs/gzip.c b/sys/cddl/boot/zfs/gzip.c
new file mode 100644
index 000000000000..35b5a3241dc0
--- /dev/null
+++ b/sys/cddl/boot/zfs/gzip.c
@@ -0,0 +1,96 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+/*
+ * Portions Copyright 2022 Mikhail Zakharov <zmey20000@yahoo.com>
+ */
+
+#include <contrib/zlib/zlib.h>
+#include <contrib/zlib/zutil.h>
+
+static void *
+zfs_zcalloc(void *opaque __unused, uint_t items, uint_t size)
+{
+
+	return (calloc(items, size));
+}
+
+static void
+zfs_zcfree(void *opaque __unused, void *ptr)
+{
+	free(ptr);
+}
+
+/*
+ * Uncompress the buffer 'src' into the buffer 'dst'.  The caller must store
+ * the expected decompressed data size externally so it can be passed in.
+ * The resulting decompressed size is then returned through dstlen.  This
+ * function return Z_OK on success, or another error code on failure.
+ */
+static inline int
+z_uncompress(void *dst, size_t *dstlen, const void *src, size_t srclen)
+{
+	z_stream zs;
+	int err;
+
+	bzero(&zs, sizeof (zs));
+	zs.next_in = (unsigned char *)src;
+	zs.avail_in = srclen;
+	zs.next_out = dst;
+	zs.avail_out = *dstlen;
+	zs.zalloc = zfs_zcalloc;
+	zs.zfree = zfs_zcfree;
+
+	/*
+	 * Call inflateInit2() specifying a window size of DEF_WBITS
+	 * with the 6th bit set to indicate that the compression format
+	 * type (zlib or gzip) should be automatically detected.
+	 */
+	if ((err = inflateInit2(&zs, DEF_WBITS | 0x20)) != Z_OK)
+		return (err);
+
+	if ((err = inflate(&zs, Z_FINISH)) != Z_STREAM_END) {
+		(void) inflateEnd(&zs);
+		return (err == Z_OK ? Z_BUF_ERROR : err);
+	}
+
+	*dstlen = zs.total_out;
+	return (inflateEnd(&zs));
+}
+
+static int
+gzip_decompress(void *s_start, void *d_start, size_t s_len, size_t d_len,
+    int n __unused)
+{
+	size_t dstlen = d_len;
+
+	ASSERT(d_len >= s_len);
+
+	if (z_uncompress(d_start, &dstlen, s_start, s_len) != Z_OK)
+		return (-1);
+
+	return (0);
+}