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-rw-r--r--libblkid/src/topology/sysfs.c124
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
+};
+