Adding upstream version 2:2.3.7.upstream/2%2.3.7upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1022 insertions, 0 deletions

diff --git a/lib/utils_device.c b/lib/utils_device.c
new file mode 100644
index 0000000..f4bb058
--- /dev/null
+++ b/lib/utils_device.c
@@ -0,0 +1,1022 @@
+/*
+ * device backend utilities
+ *
+ * Copyright (C) 2004 Jana Saout <jana@saout.de>
+ * Copyright (C) 2004-2007 Clemens Fruhwirth <clemens@endorphin.org>
+ * Copyright (C) 2009-2021 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2009-2021 Milan Broz
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <assert.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <linux/fs.h>
+#include <unistd.h>
+#ifdef HAVE_SYS_SYSMACROS_H
+# include <sys/sysmacros.h>     /* for major, minor */
+#endif
+#ifdef HAVE_SYS_STATVFS_H
+# include <sys/statvfs.h>
+#endif
+#include "internal.h"
+#include "utils_device_locking.h"
+
+struct device {
+	char *path;
+
+	char *file_path;
+	int loop_fd;
+
+	int ro_dev_fd;
+	int dev_fd;
+	int dev_fd_excl;
+
+	struct crypt_lock_handle *lh;
+
+	unsigned int o_direct:1;
+	unsigned int init_done:1; /* path is bdev or loop already initialized */
+
+	/* cached values */
+	size_t alignment;
+	size_t block_size;
+};
+
+static size_t device_fs_block_size_fd(int fd)
+{
+	size_t page_size = crypt_getpagesize();
+
+#ifdef HAVE_SYS_STATVFS_H
+	struct statvfs buf;
+
+	/*
+	 * NOTE: some filesystems (NFS) returns bogus blocksize (1MB).
+	 * Page-size io should always work and avoids increasing IO beyond aligned LUKS header.
+	 */
+	if (!fstatvfs(fd, &buf) && buf.f_bsize && buf.f_bsize <= page_size)
+		return (size_t)buf.f_bsize;
+#endif
+	return page_size;
+}
+
+static size_t device_block_size_fd(int fd, size_t *min_size)
+{
+	struct stat st;
+	size_t bsize;
+	int arg;
+
+	if (fstat(fd, &st) < 0)
+		return 0;
+
+	if (S_ISREG(st.st_mode))
+		bsize = device_fs_block_size_fd(fd);
+	else {
+		if (ioctl(fd, BLKSSZGET, &arg) < 0)
+			bsize = crypt_getpagesize();
+		else
+			bsize = (size_t)arg;
+	}
+
+	if (!min_size)
+		return bsize;
+
+	if (S_ISREG(st.st_mode)) {
+		/* file can be empty as well */
+		if (st.st_size > (ssize_t)bsize)
+			*min_size = bsize;
+		else
+			*min_size = st.st_size;
+	} else {
+		/* block device must have at least one block */
+		*min_size = bsize;
+	}
+
+	return bsize;
+}
+
+static size_t device_alignment_fd(int devfd)
+{
+	long alignment = DEFAULT_MEM_ALIGNMENT;
+
+#ifdef _PC_REC_XFER_ALIGN
+	alignment = fpathconf(devfd, _PC_REC_XFER_ALIGN);
+	if (alignment < 0)
+		alignment = DEFAULT_MEM_ALIGNMENT;
+#endif
+	return (size_t)alignment;
+}
+
+static int device_read_test(int devfd)
+{
+	char buffer[512];
+	int r = -EIO;
+	size_t minsize = 0, blocksize, alignment;
+
+	blocksize = device_block_size_fd(devfd, &minsize);
+	alignment = device_alignment_fd(devfd);
+
+	if (!blocksize || !alignment)
+		return -EINVAL;
+
+	if (minsize == 0)
+		return 0;
+
+	if (minsize > sizeof(buffer))
+		minsize = sizeof(buffer);
+
+	if (read_blockwise(devfd, blocksize, alignment, buffer, minsize) == (ssize_t)minsize)
+		r = 0;
+
+	crypt_safe_memzero(buffer, sizeof(buffer));
+	return r;
+}
+
+/*
+ * The direct-io is always preferred. The header is usually mapped to the same
+ * device and can be accessed when the rest of device is mapped to data device.
+ * Using direct-io ensures that we do not mess with data in cache.
+ * (But proper alignment should prevent this in the first place.)
+ * The read test is needed to detect broken configurations (seen with remote
+ * block devices) that allow open with direct-io but then fails on read.
+ */
+static int device_ready(struct crypt_device *cd, struct device *device)
+{
+	int devfd = -1, r = 0;
+	struct stat st;
+	size_t tmp_size;
+
+	if (!device)
+		return -EINVAL;
+
+	if (device->o_direct) {
+		log_dbg(cd, "Trying to open and read device %s with direct-io.",
+			device_path(device));
+		device->o_direct = 0;
+		devfd = open(device_path(device), O_RDONLY | O_DIRECT);
+		if (devfd >= 0) {
+			if (device_read_test(devfd) == 0) {
+				device->o_direct = 1;
+			} else {
+				close(devfd);
+				devfd = -1;
+			}
+		}
+	}
+
+	if (devfd < 0) {
+		log_dbg(cd, "Trying to open device %s without direct-io.",
+			device_path(device));
+		devfd = open(device_path(device), O_RDONLY);
+	}
+
+	if (devfd < 0) {
+		log_err(cd, _("Device %s does not exist or access denied."),
+			device_path(device));
+		return -EINVAL;
+	}
+
+	if (fstat(devfd, &st) < 0)
+		r = -EINVAL;
+	else if (!S_ISBLK(st.st_mode))
+		r = S_ISREG(st.st_mode) ? -ENOTBLK : -EINVAL;
+	if (r == -EINVAL) {
+		log_err(cd, _("Device %s is not compatible."),
+			device_path(device));
+		close(devfd);
+		return r;
+	}
+
+	/* Allow only increase (loop device) */
+	tmp_size = device_alignment_fd(devfd);
+	if (tmp_size > device->alignment)
+		device->alignment = tmp_size;
+
+	tmp_size = device_block_size_fd(devfd, NULL);
+	if (tmp_size > device->block_size)
+		device->block_size = tmp_size;
+
+	close(devfd);
+	return r;
+}
+
+static int _open_locked(struct crypt_device *cd, struct device *device, int flags)
+{
+	int fd;
+
+	if (!device)
+		return -EINVAL;
+
+	log_dbg(cd, "Opening locked device %s", device_path(device));
+
+	if ((flags & O_ACCMODE) != O_RDONLY && device_locked_readonly(device->lh)) {
+		log_dbg(cd, "Cannot open locked device %s in write mode. Read lock held.", device_path(device));
+		return -EAGAIN;
+	}
+
+	fd = open(device_path(device), flags);
+	if (fd < 0)
+		return -errno;
+
+	if (device_locked_verify(cd, fd, device->lh)) {
+		/* fd doesn't correspond to a locked resource */
+		close(fd);
+		log_dbg(cd, "Failed to verify lock resource for device %s.", device_path(device));
+		return -EINVAL;
+	}
+
+	return fd;
+}
+
+/*
+ * Common wrapper for device sync.
+ */
+void device_sync(struct crypt_device *cd, struct device *device)
+{
+	if (!device || device->dev_fd < 0)
+		return;
+
+	if (fsync(device->dev_fd) == -1)
+		log_dbg(cd, "Cannot sync device %s.", device_path(device));
+}
+
+/*
+ * in non-locked mode returns always fd or -1
+ *
+ * in locked mode:
+ * 	opened fd or one of:
+ * 	-EAGAIN : requested write mode while device being locked in via shared lock
+ * 	-EINVAL : invalid lock fd state
+ * 	-1	: all other errors
+ */
+static int device_open_internal(struct crypt_device *cd, struct device *device, int flags)
+{
+	int access, devfd;
+
+	if (device->o_direct)
+		flags |= O_DIRECT;
+
+	access = flags & O_ACCMODE;
+	if (access == O_WRONLY)
+		access = O_RDWR;
+
+	if (access == O_RDONLY && device->ro_dev_fd >= 0) {
+		log_dbg(cd, "Reusing open r%c fd on device %s", 'o', device_path(device));
+		return device->ro_dev_fd;
+	} else if (access == O_RDWR && device->dev_fd >= 0) {
+		log_dbg(cd, "Reusing open r%c fd on device %s", 'w', device_path(device));
+		return device->dev_fd;
+	}
+
+	if (device_locked(device->lh))
+		devfd = _open_locked(cd, device, flags);
+	else
+		devfd = open(device_path(device), flags);
+
+	if (devfd < 0) {
+		log_dbg(cd, "Cannot open device %s%s.",
+			device_path(device),
+			access != O_RDONLY ? " for write" : "");
+		return devfd;
+	}
+
+	if (access == O_RDONLY)
+		device->ro_dev_fd = devfd;
+	else
+		device->dev_fd = devfd;
+
+	return devfd;
+}
+
+int device_open(struct crypt_device *cd, struct device *device, int flags)
+{
+	if (!device)
+		return -EINVAL;
+
+	assert(!device_locked(device->lh));
+	return device_open_internal(cd, device, flags);
+}
+
+int device_open_excl(struct crypt_device *cd, struct device *device, int flags)
+{
+	const char *path;
+	struct stat st;
+
+	if (!device)
+		return -EINVAL;
+
+	assert(!device_locked(device->lh));
+
+	if (device->dev_fd_excl < 0) {
+		path = device_path(device);
+		if (stat(path, &st))
+			return -EINVAL;
+		if (!S_ISBLK(st.st_mode))
+			log_dbg(cd, "%s is not a block device. Can't open in exclusive mode.",
+				path);
+		else {
+			/* open(2) with O_EXCL (w/o O_CREAT) on regular file is undefined behaviour according to man page */
+			/* coverity[toctou] */
+			device->dev_fd_excl = open(path, O_RDONLY | O_EXCL);
+			if (device->dev_fd_excl < 0)
+				return errno == EBUSY ? -EBUSY : device->dev_fd_excl;
+			if (fstat(device->dev_fd_excl, &st) || !S_ISBLK(st.st_mode)) {
+				log_dbg(cd, "%s is not a block device. Can't open in exclusive mode.",
+					path);
+				close(device->dev_fd_excl);
+				device->dev_fd_excl = -1;
+			} else
+				log_dbg(cd, "Device %s is blocked for exclusive open.", path);
+		}
+	}
+
+	return device_open_internal(cd, device, flags);
+}
+
+void device_release_excl(struct crypt_device *cd, struct device *device)
+{
+	if (device && device->dev_fd_excl >= 0) {
+		if (close(device->dev_fd_excl))
+			log_dbg(cd, "Failed to release exclusive handle on device %s.",
+				device_path(device));
+		else
+			log_dbg(cd, "Closed exclusive fd for %s.", device_path(device));
+		device->dev_fd_excl = -1;
+	}
+}
+
+int device_open_locked(struct crypt_device *cd, struct device *device, int flags)
+{
+	if (!device)
+		return -EINVAL;
+
+	assert(!crypt_metadata_locking_enabled() || device_locked(device->lh));
+	return device_open_internal(cd, device, flags);
+}
+
+/* Avoid any read from device, expects direct-io to work. */
+int device_alloc_no_check(struct device **device, const char *path)
+{
+	struct device *dev;
+
+	if (!path) {
+		*device = NULL;
+		return 0;
+	}
+
+	dev = malloc(sizeof(struct device));
+	if (!dev)
+		return -ENOMEM;
+
+	memset(dev, 0, sizeof(struct device));
+	dev->path = strdup(path);
+	if (!dev->path) {
+		free(dev);
+		return -ENOMEM;
+	}
+	dev->loop_fd = -1;
+	dev->ro_dev_fd = -1;
+	dev->dev_fd = -1;
+	dev->dev_fd_excl = -1;
+	dev->o_direct = 1;
+
+	*device = dev;
+	return 0;
+}
+
+int device_alloc(struct crypt_device *cd, struct device **device, const char *path)
+{
+	struct device *dev;
+	int r;
+
+	r = device_alloc_no_check(&dev, path);
+	if (r < 0)
+		return r;
+
+	if (dev) {
+		r = device_ready(cd, dev);
+		if (!r) {
+			dev->init_done = 1;
+		} else if (r == -ENOTBLK) {
+			/* alloc loop later */
+		} else if (r < 0) {
+			free(dev->path);
+			free(dev);
+			return -ENOTBLK;
+		}
+	}
+
+	*device = dev;
+	return 0;
+}
+
+void device_free(struct crypt_device *cd, struct device *device)
+{
+	if (!device)
+		return;
+
+	device_close(cd, device);
+
+	if (device->dev_fd_excl != -1) {
+		log_dbg(cd, "Closed exclusive fd for %s.", device_path(device));
+		close(device->dev_fd_excl);
+	}
+
+	if (device->loop_fd != -1) {
+		log_dbg(cd, "Closed loop %s (%s).", device->path, device->file_path);
+		close(device->loop_fd);
+	}
+
+	assert(!device_locked(device->lh));
+
+	free(device->file_path);
+	free(device->path);
+	free(device);
+}
+
+/* Get block device path */
+const char *device_block_path(const struct device *device)
+{
+	if (!device || !device->init_done)
+		return NULL;
+
+	return device->path;
+}
+
+/* Get device-mapper name of device (if possible) */
+const char *device_dm_name(const struct device *device)
+{
+	const char *dmdir = dm_get_dir();
+	size_t dmdir_len = strlen(dmdir);
+
+	if (!device || !device->init_done)
+		return NULL;
+
+	if (strncmp(device->path, dmdir, dmdir_len))
+		return NULL;
+
+	return &device->path[dmdir_len+1];
+}
+
+/* Get path to device / file */
+const char *device_path(const struct device *device)
+{
+	if (!device)
+		return NULL;
+
+	if (device->file_path)
+		return device->file_path;
+
+	return device->path;
+}
+
+/* block device topology ioctls, introduced in 2.6.32 */
+#ifndef BLKIOMIN
+#define BLKIOMIN    _IO(0x12,120)
+#define BLKIOOPT    _IO(0x12,121)
+#define BLKALIGNOFF _IO(0x12,122)
+#endif
+
+void device_topology_alignment(struct crypt_device *cd,
+			       struct device *device,
+			       unsigned long *required_alignment, /* bytes */
+			       unsigned long *alignment_offset,   /* bytes */
+			       unsigned long default_alignment)
+{
+	int dev_alignment_offset = 0;
+	unsigned int min_io_size = 0, opt_io_size = 0;
+	unsigned long temp_alignment = 0;
+	int fd;
+
+	*required_alignment = default_alignment;
+	*alignment_offset = 0;
+
+	if (!device || !device->path) //FIXME
+		return;
+
+	fd = open(device->path, O_RDONLY);
+	if (fd == -1)
+		return;
+
+	/* minimum io size */
+	if (ioctl(fd, BLKIOMIN, &min_io_size) == -1) {
+		log_dbg(cd, "Topology info for %s not supported, using default offset %lu bytes.",
+			device->path, default_alignment);
+		goto out;
+	}
+
+	/* optimal io size */
+	if (ioctl(fd, BLKIOOPT, &opt_io_size) == -1)
+		opt_io_size = min_io_size;
+
+	/* alignment offset, bogus -1 means misaligned/unknown */
+	if (ioctl(fd, BLKALIGNOFF, &dev_alignment_offset) == -1 || dev_alignment_offset < 0)
+		dev_alignment_offset = 0;
+	*alignment_offset = (unsigned long)dev_alignment_offset;
+
+	temp_alignment = (unsigned long)min_io_size;
+
+	/*
+	 * Ignore bogus opt-io that could break alignment.
+	 * Also real opt_io_size should be aligned to minimal page size (4k).
+	 * Some bogus USB enclosures reports wrong data here.
+	 */
+	if ((temp_alignment < (unsigned long)opt_io_size) &&
+	    !((unsigned long)opt_io_size % temp_alignment) && !MISALIGNED_4K(opt_io_size))
+		temp_alignment = (unsigned long)opt_io_size;
+	else if (opt_io_size && (opt_io_size != min_io_size))
+		log_err(cd, _("Ignoring bogus optimal-io size for data device (%u bytes)."), opt_io_size);
+
+	/* If calculated alignment is multiple of default, keep default */
+	if (temp_alignment && (default_alignment % temp_alignment))
+		*required_alignment = temp_alignment;
+
+	log_dbg(cd, "Topology: IO (%u/%u), offset = %lu; Required alignment is %lu bytes.",
+		min_io_size, opt_io_size, *alignment_offset, *required_alignment);
+out:
+	(void)close(fd);
+}
+
+size_t device_block_size(struct crypt_device *cd, struct device *device)
+{
+	int fd;
+
+	if (!device)
+		return 0;
+
+	if (device->block_size)
+		return device->block_size;
+
+	fd = open(device->file_path ?: device->path, O_RDONLY);
+	if (fd >= 0) {
+		device->block_size = device_block_size_fd(fd, NULL);
+		close(fd);
+	}
+
+	if (!device->block_size)
+		log_dbg(cd, "Cannot get block size for device %s.", device_path(device));
+
+	return device->block_size;
+}
+
+int device_read_ahead(struct device *device, uint32_t *read_ahead)
+{
+	int fd, r = 0;
+	long read_ahead_long;
+
+	if (!device)
+		return 0;
+
+	if ((fd = open(device->path, O_RDONLY)) < 0)
+		return 0;
+
+	r = ioctl(fd, BLKRAGET, &read_ahead_long) ? 0 : 1;
+	close(fd);
+
+	if (r)
+		*read_ahead = (uint32_t) read_ahead_long;
+
+	return r;
+}
+
+/* Get data size in bytes */
+int device_size(struct device *device, uint64_t *size)
+{
+	struct stat st;
+	int devfd, r = -EINVAL;
+
+	if (!device)
+		return -EINVAL;
+
+	devfd = open(device->path, O_RDONLY);
+	if (devfd == -1)
+		return -EINVAL;
+
+	if (fstat(devfd, &st) < 0)
+		goto out;
+
+	if (S_ISREG(st.st_mode)) {
+		*size = (uint64_t)st.st_size;
+		r = 0;
+	} else if (ioctl(devfd, BLKGETSIZE64, size) >= 0)
+		r = 0;
+out:
+	close(devfd);
+	return r;
+}
+
+/* For a file, allocate the required space */
+int device_fallocate(struct device *device, uint64_t size)
+{
+	struct stat st;
+	int devfd, r = -EINVAL;
+
+	if (!device)
+		return -EINVAL;
+
+	devfd = open(device_path(device), O_RDWR);
+	if (devfd == -1)
+		return -EINVAL;
+
+	if (!fstat(devfd, &st) && S_ISREG(st.st_mode) &&
+	    ((uint64_t)st.st_size >= size || !posix_fallocate(devfd, 0, size))) {
+		r = 0;
+		if (device->file_path && crypt_loop_resize(device->path))
+			r = -EINVAL;
+	}
+
+	close(devfd);
+	return r;
+}
+
+int device_check_size(struct crypt_device *cd,
+		      struct device *device,
+		      uint64_t req_offset, int falloc)
+{
+	uint64_t dev_size;
+
+	if (device_size(device, &dev_size)) {
+		log_dbg(cd, "Cannot get device size for device %s.", device_path(device));
+		return -EIO;
+	}
+
+	log_dbg(cd, "Device size %" PRIu64 ", offset %" PRIu64 ".", dev_size, req_offset);
+
+	if (req_offset > dev_size) {
+		/* If it is header file, increase its size */
+		if (falloc && !device_fallocate(device, req_offset))
+			return 0;
+
+		log_err(cd, _("Device %s is too small. Need at least %" PRIu64 " bytes."),
+			device_path(device), req_offset);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int device_info(struct crypt_device *cd,
+		       struct device *device,
+		       enum devcheck device_check,
+		       int *readonly, uint64_t *size)
+{
+	struct stat st;
+	int fd = -1, r, flags = 0, real_readonly;
+	uint64_t real_size;
+
+	if (!device)
+		return -ENOTBLK;
+
+	real_readonly = 0;
+	real_size = 0;
+
+	if (stat(device->path, &st) < 0) {
+		r = -EINVAL;
+		goto out;
+	}
+
+	/* never wipe header on mounted device */
+	if (device_check == DEV_EXCL && S_ISBLK(st.st_mode))
+		flags |= O_EXCL;
+
+	/* Try to open read-write to check whether it is a read-only device */
+	/* coverity[toctou] */
+	fd = open(device->path, O_RDWR | flags);
+	if (fd == -1 && errno == EROFS) {
+		real_readonly = 1;
+		fd = open(device->path, O_RDONLY | flags);
+	}
+
+	if (fd == -1 && device_check == DEV_EXCL && errno == EBUSY) {
+		r = -EBUSY;
+		goto out;
+	}
+
+	if (fd == -1) {
+		r = errno ? -errno : -EINVAL;
+		goto out;
+	}
+
+	r = 0;
+	if (S_ISREG(st.st_mode)) {
+		//FIXME: add readonly check
+		real_size = (uint64_t)st.st_size;
+		real_size >>= SECTOR_SHIFT;
+	} else {
+		/* If the device can be opened read-write, i.e. readonly is still 0, then
+		 * check whether BKROGET says that it is read-only. E.g. read-only loop
+		 * devices may be opened read-write but are read-only according to BLKROGET
+		 */
+		if (real_readonly == 0 && (r = ioctl(fd, BLKROGET, &real_readonly)) < 0)
+			goto out;
+
+		r = ioctl(fd, BLKGETSIZE64, &real_size);
+		if (r >= 0) {
+			real_size >>= SECTOR_SHIFT;
+			goto out;
+		}
+	}
+out:
+	if (fd != -1)
+		close(fd);
+
+	switch (r) {
+	case 0:
+		if (readonly)
+			*readonly = real_readonly;
+		if (size)
+			*size = real_size;
+		break;
+	case -EBUSY:
+		log_err(cd, _("Cannot use device %s which is in use "
+			      "(already mapped or mounted)."), device_path(device));
+		break;
+	case -EACCES:
+		log_err(cd, _("Cannot use device %s, permission denied."), device_path(device));
+		break;
+	default:
+		log_err(cd, _("Cannot get info about device %s."), device_path(device));
+		r = -EINVAL;
+	}
+
+	return r;
+}
+
+int device_check_access(struct crypt_device *cd,
+			struct device *device,
+			enum devcheck device_check)
+{
+	return device_info(cd, device, device_check, NULL, NULL);
+}
+
+static int device_internal_prepare(struct crypt_device *cd, struct device *device)
+{
+	char *loop_device = NULL, *file_path = NULL;
+	int r, loop_fd, readonly = 0;
+
+	if (device->init_done)
+		return 0;
+
+	if (getuid() || geteuid()) {
+		log_err(cd, _("Cannot use a loopback device, "
+			      "running as non-root user."));
+		return -ENOTSUP;
+	}
+
+	log_dbg(cd, "Allocating a free loop device.");
+
+	/* Keep the loop open, detached on last close. */
+	loop_fd = crypt_loop_attach(&loop_device, device->path, 0, 1, &readonly);
+	if (loop_fd == -1) {
+		log_err(cd, _("Attaching loopback device failed "
+			"(loop device with autoclear flag is required)."));
+		free(loop_device);
+		return -EINVAL;
+	}
+
+	file_path = device->path;
+	device->path = loop_device;
+
+	r = device_ready(cd, device);
+	if (r < 0) {
+		device->path = file_path;
+		crypt_loop_detach(loop_device);
+		free(loop_device);
+		return r;
+	}
+
+	device->loop_fd = loop_fd;
+	device->file_path = file_path;
+	device->init_done = 1;
+
+	return 0;
+}
+
+int device_block_adjust(struct crypt_device *cd,
+			struct device *device,
+			enum devcheck device_check,
+			uint64_t device_offset,
+			uint64_t *size,
+			uint32_t *flags)
+{
+	int r, real_readonly;
+	uint64_t real_size;
+
+	if (!device)
+		return -ENOTBLK;
+
+	r = device_internal_prepare(cd, device);
+	if (r)
+		return r;
+
+	r = device_info(cd, device, device_check, &real_readonly, &real_size);
+	if (r)
+		return r;
+
+	if (device_offset >= real_size) {
+		log_err(cd, _("Requested offset is beyond real size of device %s."),
+			device_path(device));
+		return -EINVAL;
+	}
+
+	if (size && !*size) {
+		*size = real_size;
+		if (!*size) {
+			log_err(cd, _("Device %s has zero size."), device_path(device));
+			return -ENOTBLK;
+		}
+		*size -= device_offset;
+	}
+
+	/* in case of size is set by parameter */
+	if (size && ((real_size - device_offset) < *size)) {
+		log_dbg(cd, "Device %s: offset = %" PRIu64 " requested size = %" PRIu64
+			", backing device size = %" PRIu64,
+			device->path, device_offset, *size, real_size);
+		log_err(cd, _("Device %s is too small."), device_path(device));
+		return -EINVAL;
+	}
+
+	if (flags && real_readonly)
+		*flags |= CRYPT_ACTIVATE_READONLY;
+
+	if (size)
+		log_dbg(cd, "Calculated device size is %" PRIu64" sectors (%s), offset %" PRIu64 ".",
+		*size, real_readonly ? "RO" : "RW", device_offset);
+	return 0;
+}
+
+size_t size_round_up(size_t size, size_t block)
+{
+	size_t s = (size + (block - 1)) / block;
+	return s * block;
+}
+
+void device_disable_direct_io(struct device *device)
+{
+	if (device)
+		device->o_direct = 0;
+}
+
+int device_direct_io(const struct device *device)
+{
+	return device ? device->o_direct : 0;
+}
+
+static int device_compare_path(const char *path1, const char *path2)
+{
+	struct stat st_path1, st_path2;
+
+	if (stat(path1, &st_path1 ) < 0 || stat(path2, &st_path2 ) < 0)
+		return -EINVAL;
+
+	if (S_ISBLK(st_path1.st_mode) && S_ISBLK(st_path2.st_mode))
+		return (st_path1.st_rdev == st_path2.st_rdev) ? 1 : 0;
+
+	if (S_ISREG(st_path1.st_mode) && S_ISREG(st_path2.st_mode))
+		return (st_path1.st_ino == st_path2.st_ino &&
+			st_path1.st_dev == st_path2.st_dev) ? 1 : 0;
+
+	return 0;
+}
+
+int device_is_identical(struct device *device1, struct device *device2)
+{
+	if (!device1 || !device2)
+		return 0;
+
+	if (device1 == device2)
+		return 1;
+
+	if (!strcmp(device_path(device1), device_path(device2)))
+		return 1;
+
+	return device_compare_path(device_path(device1), device_path(device2));
+}
+
+int device_is_rotational(struct device *device)
+{
+	struct stat st;
+
+	if (!device)
+		return -EINVAL;
+
+	if (stat(device_path(device), &st) < 0)
+		return -EINVAL;
+
+	if (!S_ISBLK(st.st_mode))
+		return 0;
+
+	return crypt_dev_is_rotational(major(st.st_rdev), minor(st.st_rdev));
+}
+
+size_t device_alignment(struct device *device)
+{
+	int devfd;
+
+	if (!device)
+		return -EINVAL;
+
+	if (!device->alignment) {
+		devfd = open(device_path(device), O_RDONLY);
+		if (devfd != -1) {
+			device->alignment = device_alignment_fd(devfd);
+			close(devfd);
+		}
+	}
+
+	return device->alignment;
+}
+
+void device_set_lock_handle(struct device *device, struct crypt_lock_handle *h)
+{
+	if (device)
+		device->lh = h;
+}
+
+struct crypt_lock_handle *device_get_lock_handle(struct device *device)
+{
+	return device ? device->lh : NULL;
+}
+
+int device_read_lock(struct crypt_device *cd, struct device *device)
+{
+	if (!device || !crypt_metadata_locking_enabled())
+		return 0;
+
+	if (device_read_lock_internal(cd, device))
+		return -EBUSY;
+
+	return 0;
+}
+
+int device_write_lock(struct crypt_device *cd, struct device *device)
+{
+	if (!device || !crypt_metadata_locking_enabled())
+		return 0;
+
+	assert(!device_locked(device->lh) || !device_locked_readonly(device->lh));
+
+	return device_write_lock_internal(cd, device);
+}
+
+void device_read_unlock(struct crypt_device *cd, struct device *device)
+{
+	if (!device || !crypt_metadata_locking_enabled())
+		return;
+
+	assert(device_locked(device->lh));
+
+	device_unlock_internal(cd, device);
+}
+
+void device_write_unlock(struct crypt_device *cd, struct device *device)
+{
+	if (!device || !crypt_metadata_locking_enabled())
+		return;
+
+	assert(device_locked(device->lh) && !device_locked_readonly(device->lh));
+
+	device_unlock_internal(cd, device);
+}
+
+bool device_is_locked(struct device *device)
+{
+	return device ? device_locked(device->lh) : 0;
+}
+
+void device_close(struct crypt_device *cd, struct device *device)
+{
+	if (!device)
+		return;
+
+	if (device->ro_dev_fd != -1) {
+		log_dbg(cd, "Closing read only fd for %s.", device_path(device));
+		if (close(device->ro_dev_fd))
+			log_dbg(cd, "Failed to close read only fd for %s.", device_path(device));
+		device->ro_dev_fd = -1;
+	}
+
+	if (device->dev_fd != -1) {
+		log_dbg(cd, "Closing read write fd for %s.", device_path(device));
+		if (close(device->dev_fd))
+			log_dbg(cd, "Failed to close read write fd for %s.", device_path(device));
+		device->dev_fd = -1;
+	}
+}