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-rw-r--r--libblkid/topology.c366
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diff --git a/libblkid/topology.c b/libblkid/topology.c
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+/*
+ * 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.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stddef.h>
+
+#include "topology.h"
+
+/**
+ * SECTION:topology
+ * @title: Topology information
+ * @short_description: block device topology information.
+ *
+ * The topology 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:
+ *
+ * @LOGICAL_SECTOR_SIZE: this is the smallest unit the storage device can
+ * address. It is typically 512 bytes.
+ *
+ * @PHYSICAL_SECTOR_SIZE: this is the smallest unit a physical storage device
+ * can write atomically. It is usually the same as the
+ * logical sector size but may be bigger.
+ *
+ * @MINIMUM_IO_SIZE: minimum size which is the device's preferred unit of I/O.
+ * For RAID arrays it is often the stripe chunk size.
+ *
+ * @OPTIMAL_IO_SIZE: usually the stripe width for RAID or zero. For RAID arrays
+ * it is usually the stripe width or the internal track size.
+ *
+ * @ALIGNMENT_OFFSET: indicates how many bytes the beginning of the device is
+ * offset from the disk's natural alignment.
+ *
+ * The NAME=value tags are not defined when the corresponding topology value
+ * is zero. The MINIMUM_IO_SIZE should be always defined if kernel provides
+ * topology information.
+ *
+ * Binary interface:
+ *
+ * blkid_probe_get_topology()
+ *
+ * blkid_topology_get_'VALUENAME'()
+ */
+static int topology_probe(blkid_probe pr, struct blkid_chain *chn);
+static void topology_free(blkid_probe pr, void *data);
+static int topology_is_complete(blkid_probe pr);
+static int topology_set_logical_sector_size(blkid_probe pr);
+
+/*
+ * Binary interface
+ */
+struct blkid_struct_topology {
+ unsigned long alignment_offset;
+ unsigned long minimum_io_size;
+ unsigned long optimal_io_size;
+ unsigned long logical_sector_size;
+ unsigned long physical_sector_size;
+};
+
+/*
+ * Topology chain probing functions
+ */
+static const struct blkid_idinfo *idinfos[] =
+{
+#ifdef __linux__
+ &ioctl_tp_idinfo,
+ &sysfs_tp_idinfo,
+ &md_tp_idinfo,
+ &dm_tp_idinfo,
+ &lvm_tp_idinfo,
+ &evms_tp_idinfo
+#endif
+};
+
+
+/*
+ * Driver definition
+ */
+const struct blkid_chaindrv topology_drv = {
+ .id = BLKID_CHAIN_TOPLGY,
+ .name = "topology",
+ .dflt_enabled = FALSE,
+ .idinfos = idinfos,
+ .nidinfos = ARRAY_SIZE(idinfos),
+ .probe = topology_probe,
+ .safeprobe = topology_probe,
+ .free_data = topology_free
+};
+
+/**
+ * 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.
+ *
+ * WARNING: the returned object will be overwritten by the next
+ * blkid_probe_get_topology() call for the same @pr. If you want to
+ * use more blkid_topopogy objects in the same time you have to create
+ * more blkid_probe handlers (see blkid_new_probe()).
+ *
+ * Returns: blkid_topopogy, 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]);
+}
+
+/*
+ * The blkid_do_probe() backend.
+ */
+static int topology_probe(blkid_probe pr, struct blkid_chain *chn)
+{
+ size_t i;
+
+ if (!pr || chn->idx < -1)
+ return -1;
+
+ if (!S_ISBLK(pr->mode))
+ return -1; /* nothing, works with block devices only */
+
+ 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;
+ }
+ }
+
+ blkid_probe_chain_reset_vals(pr, chn);
+
+ DBG(DEBUG_LOWPROBE,
+ printf("--> starting probing loop [TOPOLOGY idx=%d]\n",
+ chn->idx));
+
+ i = chn->idx < 0 ? 0 : chn->idx + 1U;
+
+ for ( ; i < ARRAY_SIZE(idinfos); i++) {
+ const struct blkid_idinfo *id = idinfos[i];
+
+ chn->idx = i;
+
+ if (id->probefunc) {
+ DBG(DEBUG_LOWPROBE, printf(
+ "%s: call probefunc()\n", id->name));
+ if (id->probefunc(pr, NULL) != 0)
+ continue;
+ }
+
+ if (!topology_is_complete(pr))
+ continue;
+
+ /* generic for all probing drivers */
+ topology_set_logical_sector_size(pr);
+
+ DBG(DEBUG_LOWPROBE,
+ printf("<-- leaving probing loop (type=%s) [TOPOLOGY idx=%d]\n",
+ id->name, chn->idx));
+ return 0;
+ }
+
+ DBG(DEBUG_LOWPROBE,
+ printf("<-- leaving probing loop (failed) [TOPOLOGY idx=%d]\n",
+ chn->idx));
+ return 1;
+}
+
+static void topology_free(blkid_probe pr __attribute__((__unused__)),
+ void *data)
+{
+ free(data);
+}
+
+static int topology_set_value(blkid_probe pr, const char *name,
+ size_t structoff, unsigned long data)
+{
+ struct blkid_chain *chn = blkid_probe_get_chain(pr);
+
+ if (!chn)
+ return -1;
+ if (!data)
+ return 0; /* ignore zeros */
+
+ if (chn->binary) {
+ memcpy(chn->data + structoff, &data, sizeof(data));
+ return 0;
+ }
+ return blkid_probe_sprintf_value(pr, name, "%lu", data);
+}
+
+
+/* the topology info is complete when we have at least "minimum_io_size" which
+ * is provided by all blkid topology drivers */
+static int topology_is_complete(blkid_probe pr)
+{
+ struct blkid_chain *chn = blkid_probe_get_chain(pr);
+
+ if (!chn)
+ return FALSE;
+
+ if (chn->binary && chn->data) {
+ blkid_topology tp = (blkid_topology) chn->data;
+ if (tp->minimum_io_size)
+ return TRUE;
+ }
+
+ return __blkid_probe_lookup_value(pr, "MINIMUM_IO_SIZE") ? TRUE : FALSE;
+}
+
+int blkid_topology_set_alignment_offset(blkid_probe pr, int val)
+{
+ unsigned long xval;
+
+ /* Welcome to Hell. The kernel is able to return -1 as an
+ * alignment_offset if no compatible sizes and alignments
+ * exist for stacked devices.
+ *
+ * There is no way how libblkid caller can respond to the value -1, so
+ * we will hide this corner case...
+ *
+ * (TODO: maybe we can export an extra boolean value 'misaligned' rather
+ * then complete hide this problem.)
+ */
+ xval = val < 0 ? 0 : val;
+
+ return topology_set_value(pr,
+ "ALIGNMENT_OFFSET",
+ offsetof(struct blkid_struct_topology, alignment_offset),
+ xval);
+}
+
+int blkid_topology_set_minimum_io_size(blkid_probe pr, unsigned long val)
+{
+ return topology_set_value(pr,
+ "MINIMUM_IO_SIZE",
+ offsetof(struct blkid_struct_topology, minimum_io_size),
+ val);
+}
+
+int blkid_topology_set_optimal_io_size(blkid_probe pr, unsigned long val)
+{
+ return topology_set_value(pr,
+ "OPTIMAL_IO_SIZE",
+ offsetof(struct blkid_struct_topology, optimal_io_size),
+ val);
+}
+
+/* BLKSSZGET is provided on all systems since 2.3.3 -- so we don't have to
+ * waste time with sysfs.
+ */
+static int topology_set_logical_sector_size(blkid_probe pr)
+{
+ unsigned long val = blkid_probe_get_sectorsize(pr);
+
+ if (!val)
+ return -1;
+
+ return topology_set_value(pr,
+ "LOGICAL_SECTOR_SIZE",
+ offsetof(struct blkid_struct_topology, logical_sector_size),
+ val);
+}
+
+int blkid_topology_set_physical_sector_size(blkid_probe pr, unsigned long val)
+{
+ return topology_set_value(pr,
+ "PHYSICAL_SECTOR_SIZE",
+ offsetof(struct blkid_struct_topology, physical_sector_size),
+ val);
+}
+
+/**
+ * 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->alignment_offset;
+}
+
+/**
+ * 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->minimum_io_size;
+}
+
+/**
+ * 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->optimal_io_size;
+}
+
+/**
+ * blkid_topology_get_logical_sector_size
+ * @tp: topology
+ *
+ * Returns: logical sector size (BLKSSZGET ioctl) in bytes or 0.
+ */
+unsigned long blkid_topology_get_logical_sector_size(blkid_topology tp)
+{
+ return tp->logical_sector_size;
+}
+
+/**
+ * blkid_topology_get_physical_sector_size
+ * @tp: topology
+ *
+ * Returns: logical sector size (BLKSSZGET ioctl) in bytes or 0.
+ */
+unsigned long blkid_topology_get_physical_sector_size(blkid_topology tp)
+{
+ return tp->physical_sector_size;
+}
+
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