/*
* 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 resut */
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 },
};
static int probe_sysfs_tp(blkid_probe pr,
const struct blkid_idmag *mag __attribute__((__unused__)))
{
dev_t dev, disk = 0;
int rc;
struct sysfs_cxt sysfs = UL_SYSFSCXT_EMPTY,
parent = UL_SYSFSCXT_EMPTY;
size_t i, count = 0;
dev = blkid_probe_get_devno(pr);
if (!dev || sysfs_init(&sysfs, dev, NULL) != 0)
return 1;
rc = 1; /* nothing (default) */
for (i = 0; i < ARRAY_SIZE(topology_vals); i++) {
struct topology_val *val = &topology_vals[i];
int ok = sysfs_has_attribute(&sysfs, val->attr);
rc = 1; /* nothing */
if (!ok) {
if (!disk) {
/*
* Read atrributes from "disk" if the current
* device is a partition.
*/
disk = blkid_probe_get_wholedisk_devno(pr);
if (disk && disk != dev) {
if (sysfs_init(&parent, disk, NULL) != 0)
goto done;
sysfs.parent = &parent;
ok = sysfs_has_attribute(&sysfs,
val->attr);
}
}
if (!ok)
continue; /* attribute does not exist */
}
if (val->set_ulong) {
uint64_t data;
if (sysfs_read_u64(&sysfs, val->attr, &data) != 0)
continue;
rc = val->set_ulong(pr, (unsigned long) data);
} else if (val->set_int) {
int64_t data;
if (sysfs_read_s64(&sysfs, val->attr, &data) != 0)
continue;
rc = val->set_int(pr, (int) data);
}
if (rc < 0)
goto done; /* error */
if (rc == 0)
count++;
}
done:
sysfs_deinit(&sysfs);
sysfs_deinit(&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
};
