1 files changed, 127 insertions, 0 deletions
diff --git a/libblkid/src/superblocks/stratis.c b/libblkid/src/superblocks/stratis.c
new file mode 100644
index 0000000..fe4a452
--- /dev/null
+++ b/libblkid/src/superblocks/stratis.c
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2018 Tony Asleson <tasleson@redhat.com>
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ */
+
+/*
+ * Specification for on disk format
+ * https://stratis-storage.github.io/StratisSoftwareDesign.pdf
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdint.h>
+#include <inttypes.h>
+
+#include "superblocks.h"
+#include "crc32c.h"
+
+/* Macro to avoid error in struct declaration. */
+#define STRATIS_UUID_LEN 32
+/* Contains 4 hyphens and trailing null byte. */
+const int STRATIS_UUID_STR_LEN = 37;
+
+struct stratis_sb {
+	uint32_t crc32;
+	uint8_t magic[16];
+	uint64_t sectors;
+	uint8_t reserved[4];
+	uint8_t pool_uuid[STRATIS_UUID_LEN];
+	uint8_t dev_uuid[STRATIS_UUID_LEN];
+	uint64_t mda_size;
+	uint64_t reserved_size;
+	uint64_t flags;
+	uint64_t initialization_time;
+} __attribute__ ((__packed__));
+
+#define BS 512
+#define FIRST_COPY_OFFSET BS
+#define SECOND_COPY_OFFSET (BS * 9)
+#define SB_AREA_SIZE (BS * 16)
+
+const char STRATIS_MAGIC[] = "!Stra0tis\x86\xff\x02^\x41rh";
+#define MAGIC_LEN (sizeof(STRATIS_MAGIC) - 1)
+
+#define _MAGIC_OFFSET (offsetof(const struct stratis_sb, magic))
+#define MAGIC_OFFSET_COPY_1 (FIRST_COPY_OFFSET + _MAGIC_OFFSET)
+#define MAGIC_OFFSET_COPY_2 (SECOND_COPY_OFFSET + _MAGIC_OFFSET)
+
+static int stratis_valid_sb(uint8_t *p)
+{
+	const struct stratis_sb *stratis = (const struct stratis_sb *)p;
+	uint32_t crc = 0;
+
+	/* generate CRC from byte position 4 for length 508 == 512 byte sector */
+	crc = crc32c(~0L, p + sizeof(stratis->crc32),
+			BS - sizeof(stratis->crc32));
+	crc ^= ~0L;
+
+	return crc == le32_to_cpu(stratis->crc32);
+}
+
+/*
+ * Format UUID string representation to include hyphens given that Stratis stores
+ * UUIDs without hyphens in the superblock to keep the UUID length a power of 2.
+ */
+static void stratis_format_uuid(const unsigned char *src_uuid,
+				unsigned char *dst_uuid)
+{
+	int i;
+
+	for (i = 0; i < STRATIS_UUID_LEN; i++) {
+		*dst_uuid++ = *src_uuid++;
+		if (i == 7 || i == 11 || i == 15 || i == 19)
+			*dst_uuid ++ = '-';
+	}
+	*dst_uuid = '\0';
+}
+
+static int probe_stratis(blkid_probe pr,
+		const struct blkid_idmag *mag __attribute__((__unused__)))
+{
+	const struct stratis_sb *stratis = NULL;
+	uint8_t *buf = blkid_probe_get_buffer(pr, 0, SB_AREA_SIZE);
+	unsigned char uuid[STRATIS_UUID_STR_LEN];
+
+	if (!buf)
+		return errno ? -errno : 1;
+
+	if (stratis_valid_sb(buf + FIRST_COPY_OFFSET)) {
+		stratis = (const struct stratis_sb *)(buf + FIRST_COPY_OFFSET);
+	} else {
+		if (!stratis_valid_sb(buf + SECOND_COPY_OFFSET))
+			return 1;
+
+		stratis = (const struct stratis_sb *)
+				(buf + SECOND_COPY_OFFSET);
+	}
+
+	stratis_format_uuid(stratis->dev_uuid, uuid);
+	blkid_probe_strncpy_uuid(pr, uuid, sizeof(uuid));
+
+	stratis_format_uuid(stratis->pool_uuid, uuid);
+	blkid_probe_set_value(pr, "POOL_UUID", uuid, sizeof(uuid));
+
+	blkid_probe_sprintf_value(pr, "BLOCKDEV_SECTORS", "%" PRIu64,
+				le64_to_cpu(stratis->sectors));
+	blkid_probe_sprintf_value(pr, "BLOCKDEV_INITTIME", "%" PRIu64,
+				le64_to_cpu(stratis->initialization_time));
+	return 0;
+}
+
+const struct blkid_idinfo stratis_idinfo = {
+	.name		= "stratis",
+	.usage		= BLKID_USAGE_RAID,
+	.probefunc	= probe_stratis,
+	.minsz		= SB_AREA_SIZE,
+	.magics		= {
+		{ .magic = STRATIS_MAGIC, .len = MAGIC_LEN,
+			.sboff = MAGIC_OFFSET_COPY_1},
+		{ .magic = STRATIS_MAGIC, .len = MAGIC_LEN,
+			.sboff = MAGIC_OFFSET_COPY_2},
+		{ NULL }
+	}
+};