UBI - Unsorted Block Images

UBI (Latin: "where?") manages multiple logical volumes on a single
flash device, specifically supporting NAND flash devices. UBI provides
a flexible partitioning concept which still allows for wear-levelling
across the whole flash device.

In a sense, UBI may be compared to the Logical Volume Manager
(LVM). Whereas LVM maps logical sector numbers to physical HDD sector
numbers, UBI maps logical eraseblocks to physical eraseblocks.

More information may be found in the UBI design documentation:
ubidesign.pdf. Which can be found here:
http://www.linux-mtd.infradead.org/doc/ubi.html

Partitioning/Re-partitioning

  An UBI volume occupies a certain number of erase blocks. This is
  limited by a configured maximum volume size, which could also be
  viewed as the partition size. Each individual UBI volume's size can
  be changed independently of the other UBI volumes, provided that the
  sum of all volume sizes doesn't exceed a certain limit.

  UBI supports dynamic volumes and static volumes. Static volumes are
  read-only and their contents are protected by CRC check sums.

Bad eraseblocks handling

  UBI transparently handles bad eraseblocks. When a physical
  eraseblock becomes bad, it is substituted by a good physical
  eraseblock, and the user does not even notice this.

Scrubbing

  On a NAND flash bit flips can occur on any write operation,
  sometimes also on read. If bit flips persist on the device, at first
  they can still be corrected by ECC, but once they accumulate,
  correction will become impossible. Thus it is best to actively scrub
  the affected eraseblock, by first copying it to a free eraseblock
  and then erasing the original. The UBI layer performs this type of
  scrubbing under the covers, transparently to the UBI volume users.

Erase Counts

  UBI maintains an erase count header per eraseblock. This frees
  higher-level layers (like file systems) from doing this and allows
  for centralized erase count management instead. The erase counts are
  used by the wear-levelling algorithm in the UBI layer. The algorithm
  itself is exchangeable.

Booting from NAND

  For booting directly from NAND flash the hardware must at least be
  capable of fetching and executing a small portion of the NAND
  flash. Some NAND flash controllers have this kind of support. They
  usually limit the window to a few kilobytes in erase block 0. This
  "initial program loader" (IPL) must then contain sufficient logic to
  load and execute the next boot phase.

  Due to bad eraseblocks, which may be randomly scattered over the
  flash device, it is problematic to store the "secondary program
  loader" (SPL) statically. Also, due to bit-flips it may become
  corrupted over time. UBI allows to solve this problem gracefully by
  storing the SPL in a small static UBI volume.

UBI volumes vs. static partitions

  UBI volumes are still very similar to static MTD partitions:

    * both consist of eraseblocks (logical eraseblocks in case of UBI
      volumes, and physical eraseblocks in case of static partitions;
    * both support three basic operations - read, write, erase.

  But UBI volumes have the following advantages over traditional
  static MTD partitions:

    * there are no eraseblock wear-leveling constraints in case of UBI
      volumes, so the user should not care about this;
    * there are no bit-flips and bad eraseblocks in case of UBI volumes.

  So, UBI volumes may be considered as flash devices with relaxed
  restrictions.

Where can it be found?

  Documentation, kernel code and applications can be found in the MTD
  gits.

What are the applications for?

  The applications help to create binary flash images for two
  purposes: pfi files (partial flash images) for in-system update of
  UBI volumes, and plain binary images, with or without OOB data in
  case of NAND, for a manufacturing step. Furthermore some tools
  are/and will be created that allow flash content analysis after a
  system has crashed.

Who did UBI?

  The original ideas, where UBI is based on, were developed by Andreas
  Arnez, Frank Haverkamp and Thomas Gleixner. Josh W. Boyer and
  some others were involved too. The implementation of the kernel
  layer was done by Artem B. Bityutskiy. The user-space applications
  and tools were written by Oliver Lohmann with contributions from
  Frank Haverkamp, Andreas Arnez, and Artem. Joern Engel contributed a
  patch which modifies JFFS2 so that it can be run on a UBI
  volume. Thomas Gleixner did modifications to the NAND layer and also
  some to JFFS2 to make it work.

Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>

1 files changed, 773 insertions, 0 deletions

diff --git a/ubi-utils/src/libubi/libubi.c b/ubi-utils/src/libubi/libubi.c
new file mode 100644
index 0000000..9b9a793
--- /dev/null
+++ b/ubi-utils/src/libubi/libubi.c
@@ -0,0 +1,773 @@
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ *
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/*
+ * UBI (Unsorted Block Images) library.
+ *
+ * Author: Artem B. Bityutskiy
+ *         Oliver Lohmann
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <limits.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <stdint.h>
+#include <mtd/ubi-user.h>
+
+#include "libubi.h"
+#include "libubi_int.h"
+#include "libubi_sysfs.h"
+
+/**
+ * struct ubi_lib - UBI library descriptor.
+ *
+ * @ubi		    general UBI information
+ *
+ * @sysfs_root	    sysfs root directory
+ * @ubi_root	    UBI root directory in sysfs
+ *
+ * @nlen_max	    full path to the "maximum volume name length" sysfs file
+ * @version	    full path to the "UBI version" sysfs file
+ *
+ * @cdev_path	    path pattern to UBI character devices
+ * @cdev_path_len   maximum length of the @cdev_path string after substitution
+ * @udev_path	    path to sysfs directories corresponding to UBI devices
+ * @wear_path	    path to sysfs file containing UBI wear information
+ * @vol_count_path  path to sysfs file containing the number of volumes in an
+ *		    UBI device
+ * @tot_ebs_path    path to sysfs file containing the total number of
+ *		    eraseblock on an UBI device
+ * @avail_ebs_path  path to sysfs file containing the number of unused
+ *		    eraseblocks on an UBI device, available for new volumes
+ * @eb_size_path    path to sysfs file containing size of UBI eraseblocks
+ * @nums_path	    path to sysfs file containing major and minor number of an
+ *		    UBI device
+ * @vol_cdev_path   path to UBI volume character devices
+ * @vdev_path	    path to sysfs directories corresponding to UBI volume
+ *		    devices
+ * @vol_nums_path   path to sysfs file containing major and minor number of an
+ *		    UBI volume device
+ * @vol_bytes_path  path to sysfs file containing size of an UBI volume device
+ *		    in bytes
+ * @vol_ebs_path    path to sysfs file containing the number of eraseblocks in
+ *		    an UBI volume device
+ * @vol_type_path   path to sysfs file containing type of an UBI volume
+ * @vol_name_path   @FIXME: Describe me.
+ *
+ * This structure is created and initialized by 'ubi_init()' and is passed to
+ * all UBI library calls.
+ */
+struct ubi_lib
+{
+	struct ubi_info ubi;
+
+	char *sysfs_root;
+	char *ubi_root;
+
+	char *nlen_max;
+	char *version;
+	char *cdev_path;
+	int  cdev_path_len;
+	char *udev_path;
+	char *wear_path;
+	char *vol_count_path;
+	char *tot_ebs_path;
+	char *avail_ebs_path;
+	char *eb_size_path;
+	char *nums_path;
+	int  vol_cdev_path_len;
+	char *vol_cdev_path;
+	char *vdev_path;
+	char *vol_nums_path;
+	char *vol_bytes_path;
+	char *vol_ebs_path;
+	char *vol_type_path;
+	char *vol_name_path;
+};
+
+
+/**
+ * mkpath - compose full path from 2 given components.
+ *
+ * @path  first component @name	 second component
+ *
+ * Returns the resulting path in case of success and %NULL in case of failure.
+ * Callers have to take care the resulting path is freed.
+ */
+static char*
+mkpath(const char *path, const char *name)
+{
+	char *n;
+	int len1 = strlen(path);
+	int len2 = strlen(name);
+
+	n = malloc(len1 + len2 + 2);
+	if (!n)
+		return NULL;
+
+	memcpy(n, path, len1);
+	if (n[len1 - 1] != '/')
+		n[len1++] = '/';
+
+	memcpy(n + len1, name, len2 + 1);
+	return n;
+}
+
+
+static int
+get_ubi_info(ubi_lib_t desc, struct ubi_info *ubi)
+{
+	int err;
+	int n = 1;
+	char *path;
+	struct stat stat;
+
+	err = sysfs_read_int(desc->version, (int*) &ubi->version);
+	if (err)
+		return -1;
+
+	err = sysfs_read_int(desc->nlen_max, (int*) &ubi->nlen_max);
+	if (err)
+		return -1;
+
+	/* Calculate number of UBI devices */
+	do {
+		char dir[20];
+
+		sprintf(&dir[0], "ubi%d", n);
+		path = mkpath(desc->sysfs_root, dir);
+		if (!path)
+			return ENOMEM;
+
+		err = lstat(path, &stat);
+		if (err == 0)
+			n += 1;
+		free(path);
+	} while (err == 0);
+
+	if (errno != ENOENT)
+		return -1;
+
+	if (n == 0) {
+		ubi_err("no UBI devices found");
+		errno = EINVAL;
+		return -1;
+	}
+
+	errno = 0;
+	ubi->dev_count = n;
+	return 0;
+}
+
+void
+ubi_dump_handler(ubi_lib_t desc)
+{
+	ubi_lib_t d = desc;
+	printf(	"UBI Library Descriptor:\n"
+		"ubi_root:	 %s\n"
+		"nlen_max:	 %s\n"
+		"version:	 %s\n"
+		"cdev_path:	 %s\n"
+		"udev_path:	 %s\n"
+		"wear_path:	 %s\n"
+		"vol_count_path: %s\n"
+		"tot_ebs_path:	 %s\n"
+		"avail_ebs_path: %s\n"
+		"eb_size_path:	 %s\n"
+		"nums_path:	 %s\n"
+		"vol_cdev_path:	 %s\n"
+		"vdev_path:	 %s\n"
+		"vol_nums_path:	 %s\n"
+		"vol_bytes_path: %s\n"
+		"vol_ebs_path:	 %s\n"
+		"vol_type_path:	 %s\n"
+		"vol_name_path:	 %s\n"
+		"cdev_path_len:	 %d\n\n",
+	       d->ubi_root, d->nlen_max, d->version, d->cdev_path,
+	       d->udev_path, d->wear_path, d->vol_count_path,
+	       d->tot_ebs_path, d->avail_ebs_path, d->eb_size_path,
+	       d->nums_path, d->vol_cdev_path, d->vdev_path,
+	       d->vol_nums_path, d->vol_bytes_path, d->vol_ebs_path,
+	       d->vol_type_path, d->vol_name_path, d->cdev_path_len);
+}
+
+int
+ubi_set_cdev_pattern(ubi_lib_t desc, const char *pattern)
+{
+	char *patt;
+
+	patt = strdup(pattern);
+	if (!patt) {
+		ubi_err("cannot allocate memory");
+		return -1;
+	}
+
+	if (desc->cdev_path)
+		free(desc->cdev_path);
+
+	desc->cdev_path = patt;
+	desc->cdev_path_len = strlen(patt) + 1 + UBI_MAX_ID_SIZE;
+
+	ubi_dbg("ubi dev pattern is now \"%s\"", patt);
+
+	return 0;
+}
+
+int
+ubi_set_vol_cdev_pattern(ubi_lib_t desc, const char *pattern)
+{
+	char *patt;
+
+	patt = strdup(pattern);
+	if (!patt) {
+		ubi_err("cannot allocate memory");
+		return -1;
+	}
+
+	free(desc->vol_cdev_path);
+	desc->vol_cdev_path = patt;
+	desc->vol_cdev_path_len = strlen(patt) + 1 + 2 * UBI_MAX_ID_SIZE;
+
+	ubi_dbg("ubi volume dev pattern is now \"%s\"", patt);
+
+	return 0;
+}
+
+int
+ubi_open(ubi_lib_t *desc)
+{
+	int err = -1;
+	ubi_lib_t res;
+	struct stat stat;
+
+	res = calloc(1, sizeof(struct ubi_lib));
+	if (!res) {
+		ubi_err("cannot allocate memory");
+		return -1;
+	}
+
+	res->cdev_path = NULL;
+	err = ubi_set_cdev_pattern(res, UBI_CDEV_PATH);
+	if (err)
+		goto error;
+
+	/* TODO: this actually has to be discovered */
+	res->sysfs_root = strdup(UBI_SYSFS_ROOT);
+	if (!res->sysfs_root)
+		goto error;
+
+	res->ubi_root = mkpath(res->sysfs_root, UBI_ROOT);
+	if (!res->ubi_root)
+		goto error;
+
+	res->nlen_max = mkpath(res->ubi_root, UBI_NLEN_MAX);
+	if (!res->nlen_max)
+		goto error;
+
+	res->version =	mkpath(res->ubi_root, UBI_VERSION);
+	if (!res->version)
+		goto error;
+
+	res->udev_path = mkpath(res->ubi_root, "ubi%d/");
+	if (!res->udev_path)
+		goto error;
+
+	res->wear_path = mkpath(res->udev_path, UBI_WEAR);
+	if (!res->wear_path)
+		goto error;
+
+	res->vol_count_path = mkpath(res->udev_path, UBI_VOL_COUNT);
+	if (!res->vol_count_path)
+		goto error;
+
+	res->tot_ebs_path = mkpath(res->udev_path, UBI_AVAIL_EBS);
+	if (!res->tot_ebs_path)
+		goto error;
+
+	res->avail_ebs_path = mkpath(res->udev_path, UBI_TOT_EBS);
+	if (!res->avail_ebs_path)
+		goto error;
+
+	res->eb_size_path = mkpath(res->udev_path, UBI_EB_SIZE);
+	if (!res->eb_size_path)
+		goto error;
+
+	res->nums_path = mkpath(res->udev_path, UBI_NUMS);
+	if (!res->nums_path)
+		goto error;
+
+	err = ubi_set_vol_cdev_pattern(res, UBI_VOL_CDEV_PATH);
+	if (err)
+		goto error;
+
+	res->vdev_path = mkpath(res->udev_path, "%d/");
+	if (!res->vdev_path)
+		goto error;
+
+	res->vol_nums_path = mkpath(res->vdev_path, UBI_NUMS);
+	if (!res->vol_nums_path)
+		goto error;
+
+	res->vol_bytes_path = mkpath(res->vdev_path, UBI_VBYTES);
+	if (!res->vol_bytes_path)
+		goto error;
+
+	res->vol_ebs_path = mkpath(res->vdev_path, UBI_VEBS);
+	if (!res->vol_ebs_path)
+		goto error;
+
+	res->vol_type_path = mkpath(res->vdev_path, UBI_VTYPE);
+	if (!res->vol_type_path)
+		goto error;
+
+	res->vol_name_path = mkpath(res->vdev_path, UBI_VNAME);
+	if (!res->vol_name_path)
+		goto error;
+
+	/* Check if UBI exists in the system */
+	err = lstat(res->ubi_root, &stat);
+	if (err) {
+		perror("lstat");
+		fprintf(stderr, "%s\n", res->ubi_root);
+		err = UBI_ENOTFOUND;
+		goto error;
+	}
+
+	err = get_ubi_info(res, &res->ubi);
+	if (err)
+		goto error;
+
+	*desc = res;
+
+	ubi_dbg("opened library successfully.");
+
+	return 0;
+
+error:
+	ubi_close(&res);
+
+	if (err == -1 && errno == ENOMEM)
+		ubi_err("Cannot allocate memory");
+
+	return err;
+}
+
+int
+ubi_close(ubi_lib_t *desc)
+{
+	ubi_lib_t tmp = *desc;
+
+	free(tmp->vol_name_path);
+	free(tmp->vol_type_path);
+	free(tmp->vol_ebs_path);
+	free(tmp->vol_bytes_path);
+	free(tmp->vol_nums_path);
+	free(tmp->vdev_path);
+	free(tmp->vol_cdev_path);
+	free(tmp->nums_path);
+	free(tmp->eb_size_path);
+	free(tmp->avail_ebs_path);
+	free(tmp->tot_ebs_path);
+	free(tmp->vol_count_path);
+	free(tmp->wear_path);
+	free(tmp->udev_path);
+	free(tmp->cdev_path);
+	free(tmp->version);
+	free(tmp->nlen_max);
+	free(tmp->ubi_root);
+	free(tmp->sysfs_root);
+	free(tmp);
+
+	*desc = NULL;
+
+	return 0;
+}
+
+void
+ubi_perror(const char *prefix, int code)
+{
+	if (code == 0)
+		return;
+
+	fprintf(stderr, "%s: ", prefix);
+
+	switch (code) {
+	case UBI_ENOTFOUND:
+		fprintf(stderr, "UBI was not found in system\n");
+		break;
+	case UBI_EBUG:
+		fprintf(stderr, "an UBI or UBI library bug\n");
+		break;
+	case UBI_EINVAL:
+		fprintf(stderr, "invalid parameter\n");
+		break;
+	case -1:
+		perror(prefix);
+		break;
+	default:
+		ubi_err("unknown error code %d", code);
+		break;
+	}
+}
+
+int
+ubi_get_dev_info(ubi_lib_t desc, unsigned int devn, struct ubi_dev_info *di)
+{
+	int err;
+
+	if (devn >= desc->ubi.dev_count) {
+		ubi_err("bad device number, max is %d\n",
+			desc->ubi.dev_count - 1);
+		return UBI_EINVAL;
+	}
+
+	err = sysfs_read_dev_subst(desc->nums_path, &di->major,
+				   &di->minor, 1, devn);
+	if (err)
+		return -1;
+
+	err = sysfs_read_ull_subst(desc->wear_path, &di->wear, 1, devn);
+	if (err)
+		return -1;
+
+	err = sysfs_read_uint_subst(desc->vol_count_path,
+				    &di->vol_count, 1, devn);
+	if (err)
+		return -1;
+
+	err = sysfs_read_uint_subst(desc->eb_size_path, &di->eb_size, 1, devn);
+	if (err)
+		return -1;
+
+	err = sysfs_read_uint_subst(desc->tot_ebs_path, &di->total_ebs, 1, devn);
+	if (err)
+		return -1;
+
+	err = sysfs_read_uint_subst(desc->avail_ebs_path,
+				    &di->avail_ebs, 1, devn);
+	if (err)
+		return -1;
+
+#if 0
+	ubi_dbg("major:minor %d:%d, wear %llu, EB size %d, "
+		"vol. count %d, tot. EBs %d, avail. EBs %d",
+		di->major, di->minor, di->wear, di->eb_size,
+		di->vol_count, di->total_ebs, di->avail_ebs);
+#endif
+
+	return err;
+}
+
+int
+ubi_get_vol_info(ubi_lib_t desc, unsigned int devn, unsigned int vol_id,
+		struct ubi_vol_info *req)
+{
+	int err;
+	int len;
+	char buf1[10];
+	char buf2[desc->ubi.nlen_max];
+
+	err = sysfs_read_dev_subst(desc->vol_nums_path, &req->major,
+				   &req->minor, 2, devn, vol_id);
+	if (err)
+		return -1;
+
+	err = sysfs_read_ull_subst(desc->vol_bytes_path,
+				   &req->bytes, 2, devn, vol_id);
+	if (err)
+		return -1;
+
+	err = sysfs_read_uint_subst(desc->vol_ebs_path,
+				    &req->eraseblocks, 2, devn, vol_id);
+	if (err)
+		return -1;
+
+	len = sysfs_read_data_subst(desc->vol_type_path, &buf1[0],
+				    10, 2,  devn, vol_id);
+	if (len == -1)
+		return -1;
+
+	if (buf1[len - 1] != '\n') {
+		ubi_err("bad volume type");
+		return UBI_EBUG;
+	}
+
+	if (!strncmp(&buf1[0], "static", sizeof("static") - 1)) {
+		req->type = UBI_STATIC_VOLUME;
+	} else if (!strncmp(&buf1[0], "dynamic", sizeof("dynamic") - 1)) {
+		req->type = UBI_DYNAMIC_VOLUME;
+	} else {
+		ubi_err("bad type %s", &buf1[0]);
+		return -1;
+	}
+
+	len = sysfs_read_data_subst(desc->vol_name_path, &buf2[0],
+				    desc->ubi.nlen_max, 2,  devn, vol_id);
+	if (len == -1)
+		return -1;
+
+	if (buf2[len - 1] != '\n') {
+		ubi_err("bad volume name");
+		return UBI_EBUG;
+	}
+
+	req->name = malloc(len);
+	if (!req->name) {
+		ubi_err("cannot allocate memory");
+		return -1;
+	}
+
+	memcpy(req->name, &buf2[0], len - 1);
+	req->name[len - 1] = '\0';
+
+	return 0;
+}
+
+/**
+ * ubi_cdev_open - open a UBI device
+ *
+ * @desc	UBI library descriptor
+ * @devn	Number of UBI device to open
+ * @flags	Flags to pass to open()
+ *
+ * This function opens a UBI device by number and returns a file
+ * descriptor.  In case of an error %-1 is returned and errno is set
+ * appropriately.
+ */
+static int
+ubi_cdev_open(ubi_lib_t desc, int devn, int flags)
+{
+	char *buf;
+	int fd;
+
+	ubi_dbg("desc=%p, devn=%d, flags=%08x\n", desc, devn, flags);
+
+	if (desc == NULL) {
+		ubi_err("desc is NULL\n");
+		return -1;
+	}
+	if (desc->vol_cdev_path_len == 0) {
+		ubi_err("path_len == 0\n");
+		return -1;
+	}
+	buf = malloc(desc->cdev_path_len);
+
+	sprintf(buf, desc->cdev_path, devn);
+
+	fd = open(buf, flags);
+	if (fd == -1)
+		ubi_dbg("cannot open %s", buf);
+
+	free(buf);
+	return fd;
+}
+
+/**
+ * ubi_cdev_close - close a UBI device
+ *
+ * @dev_fd	file descriptor of UBI device to close
+ *
+ * This function closes the given UBI device.
+ */
+static int
+ubi_cdev_close(int dev_fd)
+{
+	return close(dev_fd);
+}
+
+/**
+ * @size is now in bytes.
+ */
+int
+ubi_mkvol(ubi_lib_t desc, int devn, int vol_id, int vol_type,
+	  long long bytes, int alignment, const char *name)
+{
+	int fd;
+	int err;
+	struct ubi_mkvol_req req;
+
+	if ((fd = ubi_cdev_open(desc, devn, O_RDWR)) == -1)
+		return -1;
+
+	req.vol_id = vol_id;
+	req.bytes = bytes;
+	req.vol_type = vol_type;
+	req.alignment = alignment;
+	req.name_len = strlen(name);
+	req.name = name;
+
+	/* printf("DBG: %s(vol_id=%d, bytes=%lld, type=%d, alig=%d, nlen=%d, "
+	       "name=%s)\n", __func__, vol_id, bytes, vol_type, alignment,
+	       strlen(name), name);*/
+
+	err = ioctl(fd, UBI_IOCMKVOL, &req);
+	if (err < 0) {
+		ubi_err("ioctl returned %d errno=%d\n", err, errno);
+		goto out_close;
+	}
+
+	ubi_dbg("created volume %d, size %lld, name \"%s\" "
+		"at UBI dev %d\n", vol_id, bytes, name, devn);
+
+	close(fd);
+	return err;
+ out_close:
+	ubi_cdev_close(fd);
+	return err;
+}
+
+int
+ubi_rmvol(ubi_lib_t desc, int devn, int vol_id)
+{
+	int fd;
+	int err;
+
+	if ((fd = ubi_cdev_open(desc, devn, O_RDWR)) == -1)
+		return -1;
+
+	err = ioctl(fd, UBI_IOCRMVOL, &vol_id);
+	if (err < 0)
+		goto out_close;
+
+	ubi_dbg("removed volume %d", vol_id);
+
+ out_close:
+	ubi_cdev_close(fd);
+	return err;
+}
+
+int
+ubi_get_info(ubi_lib_t desc, struct ubi_info *ubi)
+{
+	memcpy(ubi, &desc->ubi, sizeof(struct ubi_info));
+	return 0;
+}
+
+
+int
+ubi_vol_open(ubi_lib_t desc, int devn, int vol_id, int flags)
+{
+	char *buf;
+	int fd;
+
+	ubi_dbg("desc=%p, devn=%d, vol_id=%d, flags=%08x\n",
+		desc, devn, vol_id, flags);
+
+	if (desc == NULL) {
+		ubi_err("desc is NULL\n");
+		return -1;
+	}
+	if (desc->vol_cdev_path_len == 0) {
+		ubi_err("path_len == 0\n");
+		return -1;
+	}
+	buf = malloc(desc->cdev_path_len);
+
+	sprintf(buf, desc->vol_cdev_path, devn, vol_id);
+
+	fd = open(buf, flags);
+	if (fd == -1)
+		ubi_dbg("cannot open %s", buf);
+
+	free(buf);
+	return fd;
+}
+
+int
+ubi_vol_close(int vol_fd)
+{
+	return close(vol_fd);
+}
+
+
+int
+ubi_vol_update(int vol_fd, unsigned long long bytes)
+{
+	int err;
+
+	err = ioctl(vol_fd, UBI_IOCVOLUP, &bytes);
+	if (err) {
+		ubi_err("%s failure calling update ioctl\n"
+			"    IOCTL(%08x) err=%d errno=%d\n",
+			__func__, UBI_IOCVOLUP, err, errno);
+	}
+	return err;
+}
+
+FILE *
+ubi_vol_fopen_read(ubi_lib_t desc, int devn, uint32_t vol_id)
+{
+	FILE *fp;
+	int fd;
+
+	fd = ubi_vol_open(desc, devn, vol_id, O_RDONLY);
+	if (fd == -1)
+		return NULL;
+
+	fp = fdopen(fd, "r");
+	if (fp == NULL)
+		ubi_vol_close(fd);
+
+	return fp;
+}
+
+FILE *
+ubi_vol_fopen_update(ubi_lib_t desc, int devn, uint32_t vol_id,
+		     unsigned long long bytes)
+{
+	FILE *fp;
+	int fd;
+	int err;
+
+	fd = ubi_vol_open(desc, devn, vol_id, O_RDWR);
+	if (fd == -1)
+		return NULL;
+
+	fp = fdopen(fd, "r+");
+	if (fp == NULL) {
+		printf("DBG: %s(errno=%d)\n", __func__, errno);
+		ubi_vol_close(fd);
+		return NULL;
+	}
+	err = ubi_vol_update(fd, bytes);
+	if (err < 0) {
+		printf("DBG: %s() fd=%d err=%d\n", __func__, fd, err);
+		fclose(fp);
+		return NULL;
+	}
+	return fp;
+}
+
+int
+ubi_vol_get_used_bytes(int vol_fd, unsigned long long *bytes)
+{
+	off_t res;
+
+	res = lseek(vol_fd, 0, SEEK_END);
+	if (res == (off_t)-1)
+		return -1;
+	*bytes = (unsigned long long) res;
+	res = lseek(vol_fd, 0, SEEK_SET);
+	return res == (off_t)-1 ? -1 : 0;
+}