1 files changed, 506 insertions, 0 deletions
diff --git a/lib/libzutil/os/linux/zutil_device_path_os.c b/lib/libzutil/os/linux/zutil_device_path_os.c
new file mode 100644
index 000000000000..36331fd72bf7
--- /dev/null
+++ b/lib/libzutil/os/linux/zutil_device_path_os.c
@@ -0,0 +1,506 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ */
+
+#include <ctype.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/efi_partition.h>
+
+#ifdef HAVE_LIBUDEV
+#include <libudev.h>
+#endif
+
+#include <libzutil.h>
+
+/*
+ * Append partition suffix to an otherwise fully qualified device path.
+ * This is used to generate the name the full path as its stored in
+ * ZPOOL_CONFIG_PATH for whole disk devices.  On success the new length
+ * of 'path' will be returned on error a negative value is returned.
+ */
+int
+zfs_append_partition(char *path, size_t max_len)
+{
+	int len = strlen(path);
+
+	if ((strncmp(path, UDISK_ROOT, strlen(UDISK_ROOT)) == 0) ||
+	    (strncmp(path, ZVOL_ROOT, strlen(ZVOL_ROOT)) == 0)) {
+		if (len + 6 >= max_len)
+			return (-1);
+
+		(void) strcat(path, "-part1");
+		len += 6;
+	} else {
+		if (len + 2 >= max_len)
+			return (-1);
+
+		if (isdigit(path[len-1])) {
+			(void) strcat(path, "p1");
+			len += 2;
+		} else {
+			(void) strcat(path, "1");
+			len += 1;
+		}
+	}
+
+	return (len);
+}
+
+/*
+ * Remove partition suffix from a vdev path.  Partition suffixes may take three
+ * forms: "-partX", "pX", or "X", where X is a string of digits.  The second
+ * case only occurs when the suffix is preceded by a digit, i.e. "md0p0" The
+ * third case only occurs when preceded by a string matching the regular
+ * expression "^([hsv]|xv)d[a-z]+", i.e. a scsi, ide, virtio or xen disk.
+ *
+ * caller must free the returned string
+ */
+char *
+zfs_strip_partition(char *path)
+{
+	char *tmp = strdup(path);
+	char *part = NULL, *d = NULL;
+	if (!tmp)
+		return (NULL);
+
+	if ((part = strstr(tmp, "-part")) && part != tmp) {
+		d = part + 5;
+	} else if ((part = strrchr(tmp, 'p')) &&
+	    part > tmp + 1 && isdigit(*(part-1))) {
+		d = part + 1;
+	} else if ((tmp[0] == 'h' || tmp[0] == 's' || tmp[0] == 'v') &&
+	    tmp[1] == 'd') {
+		for (d = &tmp[2]; isalpha(*d); part = ++d) { }
+	} else if (strncmp("xvd", tmp, 3) == 0) {
+		for (d = &tmp[3]; isalpha(*d); part = ++d) { }
+	}
+	if (part && d && *d != '\0') {
+		for (; isdigit(*d); d++) { }
+		if (*d == '\0')
+			*part = '\0';
+	}
+
+	return (tmp);
+}
+
+/*
+ * Same as zfs_strip_partition, but allows "/dev/" to be in the pathname
+ *
+ * path:	/dev/sda1
+ * returns:	/dev/sda
+ *
+ * Returned string must be freed.
+ */
+static char *
+zfs_strip_partition_path(char *path)
+{
+	char *newpath = strdup(path);
+	char *sd_offset;
+	char *new_sd;
+
+	if (!newpath)
+		return (NULL);
+
+	/* Point to "sda1" part of "/dev/sda1" */
+	sd_offset = strrchr(newpath, '/') + 1;
+
+	/* Get our new name "sda" */
+	new_sd = zfs_strip_partition(sd_offset);
+	if (!new_sd) {
+		free(newpath);
+		return (NULL);
+	}
+
+	/* Paste the "sda" where "sda1" was */
+	strlcpy(sd_offset, new_sd, strlen(sd_offset) + 1);
+
+	/* Free temporary "sda" */
+	free(new_sd);
+
+	return (newpath);
+}
+
+/*
+ * Strip the unwanted portion of a device path.
+ */
+char *
+zfs_strip_path(char *path)
+{
+	return (strrchr(path, '/') + 1);
+}
+
+/*
+ * Allocate and return the underlying device name for a device mapper device.
+ * If a device mapper device maps to multiple devices, return the first device.
+ *
+ * For example, dm_name = "/dev/dm-0" could return "/dev/sda". Symlinks to a
+ * DM device (like /dev/disk/by-vdev/A0) are also allowed.
+ *
+ * Returns device name, or NULL on error or no match.  If dm_name is not a DM
+ * device then return NULL.
+ *
+ * NOTE: The returned name string must be *freed*.
+ */
+static char *
+dm_get_underlying_path(const char *dm_name)
+{
+	DIR *dp = NULL;
+	struct dirent *ep;
+	char *realp;
+	char *tmp = NULL;
+	char *path = NULL;
+	char *dev_str;
+	int size;
+
+	if (dm_name == NULL)
+		return (NULL);
+
+	/* dm name may be a symlink (like /dev/disk/by-vdev/A0) */
+	realp = realpath(dm_name, NULL);
+	if (realp == NULL)
+		return (NULL);
+
+	/*
+	 * If they preface 'dev' with a path (like "/dev") then strip it off.
+	 * We just want the 'dm-N' part.
+	 */
+	tmp = strrchr(realp, '/');
+	if (tmp != NULL)
+		dev_str = tmp + 1;    /* +1 since we want the chr after '/' */
+	else
+		dev_str = tmp;
+
+	size = asprintf(&tmp, "/sys/block/%s/slaves/", dev_str);
+	if (size == -1 || !tmp)
+		goto end;
+
+	dp = opendir(tmp);
+	if (dp == NULL)
+		goto end;
+
+	/*
+	 * Return first entry (that isn't itself a directory) in the
+	 * directory containing device-mapper dependent (underlying)
+	 * devices.
+	 */
+	while ((ep = readdir(dp))) {
+		if (ep->d_type != DT_DIR) {	/* skip "." and ".." dirs */
+			size = asprintf(&path, "/dev/%s", ep->d_name);
+			break;
+		}
+	}
+
+end:
+	if (dp != NULL)
+		closedir(dp);
+	free(tmp);
+	free(realp);
+	return (path);
+}
+
+/*
+ * Return B_TRUE if device is a device mapper or multipath device.
+ * Return B_FALSE if not.
+ */
+boolean_t
+zfs_dev_is_dm(const char *dev_name)
+{
+
+	char *tmp;
+	tmp = dm_get_underlying_path(dev_name);
+	if (tmp == NULL)
+		return (B_FALSE);
+
+	free(tmp);
+	return (B_TRUE);
+}
+
+/*
+ * By "whole disk" we mean an entire physical disk (something we can
+ * label, toggle the write cache on, etc.) as opposed to the full
+ * capacity of a pseudo-device such as lofi or did.  We act as if we
+ * are labeling the disk, which should be a pretty good test of whether
+ * it's a viable device or not.  Returns B_TRUE if it is and B_FALSE if
+ * it isn't.
+ */
+boolean_t
+zfs_dev_is_whole_disk(const char *dev_name)
+{
+	struct dk_gpt *label;
+	int fd;
+
+	if ((fd = open(dev_name, O_RDONLY | O_DIRECT)) < 0)
+		return (B_FALSE);
+
+	if (efi_alloc_and_init(fd, EFI_NUMPAR, &label) != 0) {
+		(void) close(fd);
+		return (B_FALSE);
+	}
+
+	efi_free(label);
+	(void) close(fd);
+
+	return (B_TRUE);
+}
+
+/*
+ * Lookup the underlying device for a device name
+ *
+ * Often you'll have a symlink to a device, a partition device,
+ * or a multipath device, and want to look up the underlying device.
+ * This function returns the underlying device name.  If the device
+ * name is already the underlying device, then just return the same
+ * name.  If the device is a DM device with multiple underlying devices
+ * then return the first one.
+ *
+ * For example:
+ *
+ * 1. /dev/disk/by-id/ata-QEMU_HARDDISK_QM00001 -> ../../sda
+ * dev_name:	/dev/disk/by-id/ata-QEMU_HARDDISK_QM00001
+ * returns:	/dev/sda
+ *
+ * 2. /dev/mapper/mpatha (made up of /dev/sda and /dev/sdb)
+ * dev_name:	/dev/mapper/mpatha
+ * returns:	/dev/sda (first device)
+ *
+ * 3. /dev/sda (already the underlying device)
+ * dev_name:	/dev/sda
+ * returns:	/dev/sda
+ *
+ * 4. /dev/dm-3 (mapped to /dev/sda)
+ * dev_name:	/dev/dm-3
+ * returns:	/dev/sda
+ *
+ * 5. /dev/disk/by-id/scsi-0QEMU_drive-scsi0-0-0-0-part9 -> ../../sdb9
+ * dev_name:	/dev/disk/by-id/scsi-0QEMU_drive-scsi0-0-0-0-part9
+ * returns:	/dev/sdb
+ *
+ * 6. /dev/disk/by-uuid/5df030cf-3cd9-46e4-8e99-3ccb462a4e9a -> ../dev/sda2
+ * dev_name:	/dev/disk/by-uuid/5df030cf-3cd9-46e4-8e99-3ccb462a4e9a
+ * returns:	/dev/sda
+ *
+ * Returns underlying device name, or NULL on error or no match.
+ *
+ * NOTE: The returned name string must be *freed*.
+ */
+char *
+zfs_get_underlying_path(const char *dev_name)
+{
+	char *name = NULL;
+	char *tmp;
+
+	if (dev_name == NULL)
+		return (NULL);
+
+	tmp = dm_get_underlying_path(dev_name);
+
+	/* dev_name not a DM device, so just un-symlinkize it */
+	if (tmp == NULL)
+		tmp = realpath(dev_name, NULL);
+
+	if (tmp != NULL) {
+		name = zfs_strip_partition_path(tmp);
+		free(tmp);
+	}
+
+	return (name);
+}
+
+/*
+ * Given a dev name like "sda", return the full enclosure sysfs path to
+ * the disk.  You can also pass in the name with "/dev" prepended
+ * to it (like /dev/sda).
+ *
+ * For example, disk "sda" in enclosure slot 1:
+ *     dev:            "sda"
+ *     returns:        "/sys/class/enclosure/1:0:3:0/Slot 1"
+ *
+ * 'dev' must be a non-devicemapper device.
+ *
+ * Returned string must be freed.
+ */
+char *
+zfs_get_enclosure_sysfs_path(const char *dev_name)
+{
+	DIR *dp = NULL;
+	struct dirent *ep;
+	char buf[MAXPATHLEN];
+	char *tmp1 = NULL;
+	char *tmp2 = NULL;
+	char *tmp3 = NULL;
+	char *path = NULL;
+	size_t size;
+	int tmpsize;
+
+	if (dev_name == NULL)
+		return (NULL);
+
+	/* If they preface 'dev' with a path (like "/dev") then strip it off */
+	tmp1 = strrchr(dev_name, '/');
+	if (tmp1 != NULL)
+		dev_name = tmp1 + 1;    /* +1 since we want the chr after '/' */
+
+	tmpsize = asprintf(&tmp1, "/sys/block/%s/device", dev_name);
+	if (tmpsize == -1 || tmp1 == NULL) {
+		tmp1 = NULL;
+		goto end;
+	}
+
+	dp = opendir(tmp1);
+	if (dp == NULL) {
+		tmp1 = NULL;	/* To make free() at the end a NOP */
+		goto end;
+	}
+
+	/*
+	 * Look though all sysfs entries in /sys/block/<dev>/device for
+	 * the enclosure symlink.
+	 */
+	while ((ep = readdir(dp))) {
+		/* Ignore everything that's not our enclosure_device link */
+		if (strstr(ep->d_name, "enclosure_device") == NULL)
+			continue;
+
+		if (asprintf(&tmp2, "%s/%s", tmp1, ep->d_name) == -1 ||
+		    tmp2 == NULL)
+			break;
+
+		size = readlink(tmp2, buf, sizeof (buf));
+
+		/* Did readlink fail or crop the link name? */
+		if (size == -1 || size >= sizeof (buf)) {
+			free(tmp2);
+			tmp2 = NULL;	/* To make free() at the end a NOP */
+			break;
+		}
+
+		/*
+		 * We got a valid link.  readlink() doesn't terminate strings
+		 * so we have to do it.
+		 */
+		buf[size] = '\0';
+
+		/*
+		 * Our link will look like:
+		 *
+		 * "../../../../port-11:1:2/..STUFF../enclosure/1:0:3:0/SLOT 1"
+		 *
+		 * We want to grab the "enclosure/1:0:3:0/SLOT 1" part
+		 */
+		tmp3 = strstr(buf, "enclosure");
+		if (tmp3 == NULL)
+			break;
+
+		if (asprintf(&path, "/sys/class/%s", tmp3) == -1) {
+			/* If asprintf() fails, 'path' is undefined */
+			path = NULL;
+			break;
+		}
+
+		if (path == NULL)
+			break;
+	}
+
+end:
+	free(tmp2);
+	free(tmp1);
+
+	if (dp != NULL)
+		closedir(dp);
+
+	return (path);
+}
+
+#ifdef HAVE_LIBUDEV
+
+/*
+ * A disk is considered a multipath whole disk when:
+ *	DEVNAME key value has "dm-"
+ *	DM_NAME key value has "mpath" prefix
+ *	DM_UUID key exists
+ *	ID_PART_TABLE_TYPE key does not exist or is not gpt
+ */
+static boolean_t
+udev_mpath_whole_disk(struct udev_device *dev)
+{
+	const char *devname, *type, *uuid;
+
+	devname = udev_device_get_property_value(dev, "DEVNAME");
+	type = udev_device_get_property_value(dev, "ID_PART_TABLE_TYPE");
+	uuid = udev_device_get_property_value(dev, "DM_UUID");
+
+	if ((devname != NULL && strncmp(devname, "/dev/dm-", 8) == 0) &&
+	    ((type == NULL) || (strcmp(type, "gpt") != 0)) &&
+	    (uuid != NULL)) {
+		return (B_TRUE);
+	}
+
+	return (B_FALSE);
+}
+
+/*
+ * Check if a disk is effectively a multipath whole disk
+ */
+boolean_t
+is_mpath_whole_disk(const char *path)
+{
+	struct udev *udev;
+	struct udev_device *dev = NULL;
+	char nodepath[MAXPATHLEN];
+	char *sysname;
+	boolean_t wholedisk = B_FALSE;
+
+	if (realpath(path, nodepath) == NULL)
+		return (B_FALSE);
+	sysname = strrchr(nodepath, '/') + 1;
+	if (strncmp(sysname, "dm-", 3) != 0)
+		return (B_FALSE);
+	if ((udev = udev_new()) == NULL)
+		return (B_FALSE);
+	if ((dev = udev_device_new_from_subsystem_sysname(udev, "block",
+	    sysname)) == NULL) {
+		udev_device_unref(dev);
+		return (B_FALSE);
+	}
+
+	wholedisk = udev_mpath_whole_disk(dev);
+
+	udev_device_unref(dev);
+	return (wholedisk);
+}
+
+#else /* HAVE_LIBUDEV */
+
+/* ARGSUSED */
+boolean_t
+is_mpath_whole_disk(const char *path)
+{
+	return (B_FALSE);
+}
+
+#endif /* HAVE_LIBUDEV */