--- /dev/null
+/*
+ * topology - gathers information about device topology
+ *
+ * Copyright 2009 Red Hat, Inc. All rights reserved.
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ *
+ * NOTE: this chain supports one probing method only, so it's implemented
+ * without array of probing functions (idinfos array).
+ *
+ * This chain does not support probing functions filtering. The chain
+ * could be enable or disabled only.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <errno.h>
+
+#include "blkdev.h"
+#include "blkidP.h"
+
+/**
+ * SECTION:topology
+ * @title: Topology information
+ * @short_description: block device tolology information.
+ *
+ * The tolology chain provides details about Linux block devices, for more
+ * information see:
+ *
+ * Linux kernel Documentation/ABI/testing/sysfs-block
+ *
+ * NAME=value (tags) interface is enabled by blkid_probe_enable_topology(),
+ * and provides:
+ *
+ * @MINIMUM_IO_SIZE: minimum size which is the device's preferred unit of I/O
+ *
+ * @OPTIMAL_IO_SIZE: usually the stripe width for RAID or zero
+ *
+ * @ALIGNMENT_OFFSET: indicates how many bytes the beginning o the device is
+ * offset from the disk's natural alignment.
+ *
+ * Binary interface:
+ *
+ * blkid_probe_get_tolology()
+ *
+ * blkid_topology_get_'VALUENAME'()
+ */
+static int topology_probe(blkid_probe pr, struct blkid_chain *chn);
+static void topology_free(blkid_probe pr, void *data);
+
+/*
+ * Driver definition
+ */
+const struct blkid_chaindrv topology_drv = {
+ .id = BLKID_CHAIN_TOPLGY,
+ .name = "topology",
+ .dflt_enabled = FALSE,
+ .probe = topology_probe,
+ .safeprobe = topology_probe,
+ .free_data = topology_free
+};
+
+/*
+ * Binary interface
+ */
+struct blkid_struct_topology {
+ unsigned long alignment_offset;
+ unsigned long minimum_io_size;
+ unsigned long optimal_io_size;
+};
+
+/**
+ * blkid_probe_enable_topology:
+ * @pr: probe
+ * @enable: TRUE/FALSE
+ *
+ * Enables/disables the topology probing for non-binary interface.
+ *
+ * Returns: 0 on success, or -1 in case of error.
+ */
+int blkid_probe_enable_topology(blkid_probe pr, int enable)
+{
+ if (!pr)
+ return -1;
+ pr->chains[BLKID_CHAIN_TOPLGY].enabled = enable;
+ return 0;
+}
+
+/**
+ * blkid_probe_get_topology:
+ * @pr: probe
+ *
+ * This is a binary interface for topology values. See also blkid_topology_*
+ * functions.
+ *
+ * This function is independent on blkid_do_[safe,full]probe() and
+ * blkid_probe_enable_topology() calls.
+ *
+ * Returns: blkid_tolopogy, or NULL in case of error.
+ */
+blkid_topology blkid_probe_get_topology(blkid_probe pr)
+{
+ return (blkid_topology) blkid_probe_get_binary_data(pr,
+ &pr->chains[BLKID_CHAIN_TOPLGY]);
+}
+
+static unsigned long
+dev_topology_attribute(const char *attribute, dev_t dev, dev_t *primary)
+{
+ const char *sysfs_fmt_str = "/sys/dev/block/%d:%d/%s";
+ char path[PATH_MAX];
+ int len;
+ FILE *fp = NULL;
+ struct stat info;
+ unsigned long result = 0UL;
+
+ len = snprintf(path, sizeof(path), sysfs_fmt_str,
+ major(dev), minor(dev), attribute);
+ if (len < 0 || len + 1 > sizeof(path))
+ goto err;
+
+ /*
+ * check if the desired sysfs attribute exists
+ * - if not: either the kernel doesn't have topology support or the
+ * device could be a partition
+ */
+ if (stat(path, &info) < 0) {
+ if (!*primary &&
+ blkid_devno_to_wholedisk(dev, NULL, 0, primary))
+ goto err;
+
+ /* get attribute from partition's primary device */
+ len = snprintf(path, sizeof(path), sysfs_fmt_str,
+ major(*primary), minor(*primary), attribute);
+ if (len < 0 || len + 1 > sizeof(path))
+ goto err;
+ }
+
+ fp = fopen(path, "r");
+ if (!fp) {
+ DBG(DEBUG_LOWPROBE, printf(
+ "topology: %s: fopen failed, errno=%d\n", path, errno));
+ goto err;
+ }
+
+ if (fscanf(fp, "%lu", &result) != 1) {
+ DBG(DEBUG_LOWPROBE, printf(
+ "topology: %s: unexpected file format\n", path));
+ goto err;
+ }
+
+ fclose(fp);
+
+ DBG(DEBUG_LOWPROBE,
+ printf("topology: attribute %s = %lu (sectors)\n", attribute, result));
+
+ return result * DEFAULT_SECTOR_SIZE;
+err:
+ if (fp)
+ fclose(fp);
+ DBG(DEBUG_LOWPROBE,
+ printf("topology: failed to read %s attribute\n", attribute));
+ return 0;
+}
+
+/*
+ * Topology values
+ */
+static struct topology_val {
+ const char *val_name; /* NAME=value */
+ const char *sysfs_name; /* /sys/dev/block/<maj>:<min>/NAME */
+ const size_t bin_offset; /* blkid_struct_topology member */
+} topology_vals[] = {
+ { "ALIGNMENT_OFFSET", "alignment_offset",
+ offsetof(struct blkid_struct_topology, alignment_offset) },
+ { "MINIMUM_IO_SIZE", "queue/minimum_io_size",
+ offsetof(struct blkid_struct_topology, minimum_io_size) },
+ {"OPTIMAL_IO_SIZE", "queue/optimal_io_size",
+ offsetof(struct blkid_struct_topology, optimal_io_size) }
+};
+
+static int topology_set_value(blkid_probe pr, struct blkid_chain *chn,
+ struct topology_val *val, unsigned long data)
+{
+ if (chn->binary) {
+ unsigned long *v =
+ (unsigned long *) (chn->data + val->bin_offset);
+ *v = data;
+ return 0;
+ }
+ return blkid_probe_sprintf_value(pr, val->val_name, "%llu", data);
+}
+
+/*
+ * The blkid_do_probe() backend.
+ */
+static int topology_probe(blkid_probe pr, struct blkid_chain *chn)
+{
+ dev_t dev, pri_dev = 0;
+ int i, rc = 0, count = 0;
+
+ if (!pr)
+ return -1;
+
+ blkid_probe_chain_reset_vals(pr, chn);
+
+ dev = blkid_probe_get_devno(pr);
+ if (!dev)
+ return 1; /* no result */
+
+ if (chn->binary) {
+ DBG(DEBUG_LOWPROBE, printf("initialize topology binary data\n"));
+
+ if (chn->data)
+ /* reset binary data */
+ memset(chn->data, 0,
+ sizeof(struct blkid_struct_topology));
+ else {
+ chn->data = calloc(1,
+ sizeof(struct blkid_struct_topology));
+ if (!chn->data)
+ return -1;
+ }
+ }
+
+ DBG(DEBUG_LOWPROBE, printf("--> starting probing loop [TOPOLOGY]\n"));
+
+ for (i = 0; i < ARRAY_SIZE(topology_vals); i++) {
+ struct topology_val *val = &topology_vals[i];
+ unsigned long data;
+
+ /*
+ * Don't bother reporting any of the topology information
+ * if it's zero.
+ */
+ data = dev_topology_attribute(val->sysfs_name, dev, &pri_dev);
+ if (!data)
+ continue;
+
+ rc = topology_set_value(pr, chn, val, data);
+ if (rc)
+ break; /* error */
+ count++;
+ }
+
+
+ if (rc == 0 && count == 0)
+ rc = 1; /* no result */
+
+ DBG(DEBUG_LOWPROBE,
+ printf("<-- leaving probing loop [TOPOLOGY, rc=%d]\n", rc));
+ return rc;
+}
+
+static void topology_free(blkid_probe pr, void *data)
+{
+ free(data);
+}
+
+/**
+ * blkid_topology_get_alignment_offset:
+ * @tp: topology
+ *
+ * Returns: alignment offset in bytes or 0.
+ */
+unsigned long blkid_topology_get_alignment_offset(blkid_topology tp)
+{
+ return tp ? tp->alignment_offset : 0;
+}
+
+/**
+ * blkid_topology_get_minimum_io_size:
+ * @tp: topology
+ *
+ * Returns: minimum io size in bytes or 0.
+ */
+unsigned long blkid_topology_get_minimum_io_size(blkid_topology tp)
+{
+ return tp ? tp->minimum_io_size : 0;
+}
+
+/**
+ * blkid_topology_get_optimal_io_size
+ * @tp: topology
+ *
+ * Returns: optimal io size in bytes or 0.
+ */
+unsigned long blkid_topology_get_optimal_io_size(blkid_topology tp)
+{
+ return tp ? tp->optimal_io_size : 0;
+}
+
projects / util-linux / commitdiff