1 files changed, 124 insertions, 0 deletions
diff --git a/libblkid/src/topology/sysfs.c b/libblkid/src/topology/sysfs.c
new file mode 100644
index 0000000..745cd11
--- /dev/null
+++ b/libblkid/src/topology/sysfs.c
@@ -0,0 +1,124 @@
+/*
+ * sysfs based topology -- gathers topology information from Linux sysfs
+ *
+ * Copyright (C) 2009 Karel Zak <kzak@redhat.com>
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ *
+ * For more information see Linux kernel Documentation/ABI/testing/sysfs-block.
+ */
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <inttypes.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "sysfs.h"
+#include "topology.h"
+
+/*
+ * Sysfs topology values (since 2.6.31, May 2009).
+ */
+static struct topology_val {
+
+	/* /sys/dev/block/<maj>:<min>/<ATTR> */
+	const char *attr;
+
+	/* functions to set probing result */
+	int (*set_ulong)(blkid_probe, unsigned long);
+	int (*set_int)(blkid_probe, int);
+
+} topology_vals[] = {
+	{ "alignment_offset", NULL, blkid_topology_set_alignment_offset },
+	{ "queue/minimum_io_size", blkid_topology_set_minimum_io_size },
+	{ "queue/optimal_io_size", blkid_topology_set_optimal_io_size },
+	{ "queue/physical_block_size", blkid_topology_set_physical_sector_size },
+	{ "queue/dax", blkid_topology_set_dax },
+};
+
+static int probe_sysfs_tp(blkid_probe pr,
+		const struct blkid_idmag *mag __attribute__((__unused__)))
+{
+	dev_t dev;
+	int rc, set_parent = 1;
+	struct path_cxt *pc;
+	size_t i, count = 0;
+
+	dev = blkid_probe_get_devno(pr);
+	if (!dev)
+		return 1;
+	pc = ul_new_sysfs_path(dev, NULL, NULL);
+	if (!pc)
+		return 1;
+
+	rc = 1;		/* nothing (default) */
+
+	for (i = 0; i < ARRAY_SIZE(topology_vals); i++) {
+		struct topology_val *val = &topology_vals[i];
+		int ok = ul_path_access(pc, F_OK, val->attr) == 0;
+
+		rc = 1;	/* nothing */
+
+		if (!ok && set_parent) {
+			dev_t disk = blkid_probe_get_wholedisk_devno(pr);
+			set_parent = 0;
+
+			/*
+			 * Read attributes from "disk" if the current device is
+			 * a partition. Note that sysfs ul_path_* API is able
+			 * to redirect requests to attributes if parent is set.
+			 */
+			if (disk && disk != dev) {
+				struct path_cxt *parent = ul_new_sysfs_path(disk, NULL, NULL);
+				if (!parent)
+					goto done;
+
+				sysfs_blkdev_set_parent(pc, parent);
+				ul_unref_path(parent);
+
+				/* try it again */
+				ok = ul_path_access(pc, F_OK, val->attr) == 0;
+			}
+		}
+		if (!ok)
+			continue;	/* attribute does not exist */
+
+		if (val->set_ulong) {
+			uint64_t data;
+
+			if (ul_path_read_u64(pc, &data, val->attr) != 0)
+				continue;
+			rc = val->set_ulong(pr, (unsigned long) data);
+
+		} else if (val->set_int) {
+			int64_t data;
+
+			if (ul_path_read_s64(pc, &data, val->attr) != 0)
+				continue;
+			rc = val->set_int(pr, (int) data);
+		}
+
+		if (rc < 0)
+			goto done;	/* error */
+		if (rc == 0)
+			count++;
+	}
+
+done:
+	ul_unref_path(pc);		/* unref pc and parent */
+	if (count)
+		return 0;		/* success */
+	return rc;			/* error or nothing */
+}
+
+const struct blkid_idinfo sysfs_tp_idinfo =
+{
+	.name		= "sysfs",
+	.probefunc	= probe_sysfs_tp,
+	.magics		= BLKID_NONE_MAGIC
+};
+