Merge branch 'ubi'

1 files changed, 837 insertions, 0 deletions

diff --git a/ubi-utils/src/unubi.c b/ubi-utils/src/unubi.c
new file mode 100644
index 0000000..811a6db
--- /dev/null
+++ b/ubi-utils/src/unubi.c
@@ -0,0 +1,837 @@
+/*
+ * 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.
+ */
+
+/*
+ * Authors: Frank Haverkamp, haver@vnet.ibm.com
+ *	    Drake Dowsett, dowsett@de.ibm.com
+ *
+ * 1.2 Removed argp because we want to use uClibc.
+ * 1.3 Minor cleanups
+ */
+
+/*
+ * unubi  reads  an  image  file containing blocks of UBI headers and data
+ * (such as produced from nand2bin) and rebuilds the volumes within.   The
+ * default  operation  (when  no  flags are given) is to rebuild all valid
+ * volumes found in the image. unubi  can  also  read  straight  from  the
+ * onboard MTD device (ex. /dev/mtdblock/NAND).
+ */
+
+/* TODO: consideration for dynamic vs. static volumes */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <getopt.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <mtd/ubi-header.h>
+
+#include "crc32.h"
+#include "eb_chain.h"
+#include "unubi_analyze.h"
+
+#define EXEC		"unubi"
+#define CONTACT		"haver@vnet.ibm.com"
+#define VERSION		"1.3"
+
+static char doc[] = "\nVersion: " VERSION "\n\t"
+	BUILD_OS" "BUILD_CPU" at "__DATE__" "__TIME__"\n"
+	"\nAnalyze raw flash containing UBI data.\n";
+
+static const char *optionsstr =
+" OPTIONS\n"
+"  -r, --rebuild=<volume-id>  Extract and rebuild volume\n"
+"\n"
+"  -d, --dir=<output-dir>     Specify output directory\n"
+"\n"
+"  -a, --analyze              Analyze image\n"
+"\n"
+"  -b, --blocksize=<block-size>   Specify size of eraseblocks in image in bytes\n"
+"                             (default 128KiB)\n"
+"\n"
+"  -e, --eb-split             Generate individual eraseblock images (all\n"
+"                             eraseblocks)\n"
+"  -v, --vol-split            Generate individual eraseblock images (valid\n"
+"                             eraseblocks only)\n"
+"  -V, --vol-split!           Raw split by eraseblock (valid eraseblocks only)\n"
+"\n"
+"  -?, --help                 Give this help list\n"
+"      --usage                Give a short usage message\n"
+"      --version              Print program version\n";
+
+static const char *usage =
+"Usage: unubi [-aevV?] [-r <volume-id>] [-d <output-dir>] [-b <block-size>]\n"
+"            [--rebuild=<volume-id>] [--dir=<output-dir>] [--analyze]\n"
+"            [--blocksize=<block-size>] [--eb-split] [--vol-split]\n"
+"            [--vol-split!] [--help] [--usage] [--version] image-file\n";
+
+#define ERR_MSG(fmt...)							\
+	fprintf(stderr, EXEC ": " fmt)
+
+#define SPLIT_DATA	1
+#define SPLIT_RAW	2
+
+#define DIR_FMT		"unubi_%s"
+#define KIB		1024
+#define MIB		(KIB * KIB)
+#define MAXPATH		KIB
+
+/* filenames */
+#define FN_INVAL	"%s/eb%04u%s"			/* invalid eraseblock */
+#define FN_NSURE	"%s/eb%04u_%03u_%03u_%03x%s"	/* unsure eraseblock */
+#define FN_VALID	"%s/eb%04u_%03u_%03u_%03x%s"	/* valid eraseblock */
+#define FN_VOLSP	"%s/vol%03u_%03u_%03u_%04zu"	/* split volume */
+#define FN_VOLWH	"%s/volume%03u"			/* whole volume */
+
+static uint32_t crc32_table[256];
+
+/* struct args:
+ *	bsize		int, blocksize of image blocks
+ *	analyze		flag, when non-zero produce analysis
+ *	eb_split	flag, when non-zero output eb####
+ *			note: SPLIT_DATA vs. SPLIT_RAW
+ *	vol_split	flag, when non-zero output vol###_####
+ *			note: SPLIT_DATA vs. SPLIT_RAW
+ *	odir_path	string, directory to place volumes in
+ *	img_path	string, file to read as ubi image
+ *	vols		int array of size UBI_MAX_VOLUMES, where a 1 can be
+ *			written for each --rebuild flag in the index specified
+ *			then the array can be counted and collapsed using
+ *			count_set() and collapse()
+ */
+struct args {
+	uint32_t bsize;
+	int analyze;
+	int eb_split;
+	int vol_split;
+	char *odir_path;
+	char *img_path;
+	uint32_t *vols;
+
+	char **options;
+};
+
+struct option long_options[] = {
+	{ .name = "rebuild", .has_arg = 1, .flag = NULL, .val = 'r' },
+	{ .name = "dir", .has_arg = 1, .flag = NULL, .val = 'd' },
+	{ .name = "analyze", .has_arg = 0, .flag = NULL, .val = 'a' },
+	{ .name = "blocksize", .has_arg = 1, .flag = NULL, .val = 'b' },
+	{ .name = "eb-split", .has_arg = 0, .flag = NULL, .val = 'e' },
+	{ .name = "vol-split", .has_arg = 0, .flag = NULL, .val = 'v' },
+	{ .name = "vol-split!", .has_arg = 0, .flag = NULL, .val = 'e' },
+	{ .name = "help", .has_arg = 0, .flag = NULL, .val = '?' },
+	{ .name = "usage", .has_arg = 0, .flag = NULL, .val = 0 },
+	{ .name = "version", .has_arg = 0, .flag = NULL, .val = 'J' },
+	{ NULL, 0, NULL, 0}
+};
+
+/**
+ * parses out a numerical value from a string of numbers followed by:
+ *	k, K, kib, KiB for kibibyte
+ *	m, M, mib, MiB for mebibyte
+ **/
+static uint32_t
+str_to_num(char *str)
+{
+	char *s;
+	ulong num;
+
+	s = str;
+	num = strtoul(s, &s, 0);
+
+	if (*s != '\0') {
+		if ((strcmp(s, "KiB") == 0) || (strcmp(s, "K") == 0) ||
+		    (strcmp(s, "kib") == 0) || (strcmp(s, "k") == 0))
+			num *= KIB;
+		if ((strcmp(s, "MiB") == 0) || (strcmp(s, "M") == 0) ||
+		    (strcmp(s, "mib") == 0) || (strcmp(s, "m") == 0))
+			num *= MIB;
+		else
+			ERR_MSG("couldn't parse '%s', assuming %lu\n",
+				s, num);
+	}
+	return num;
+}
+
+static int
+parse_opt(int argc, char **argv, struct args *args)
+{
+	uint32_t i;
+
+	while (1) {
+		int key;
+
+		key = getopt_long(argc, argv, "r:d:ab:evV?", long_options, NULL);
+		if (key == -1)
+			break;
+
+		switch (key) {
+			case 'a':
+				args->analyze = 1;
+				break;
+			case 'b':
+				args->bsize = str_to_num(optarg);
+				break;
+			case 'd':
+				args->odir_path = optarg;
+				break;
+			case 'e':
+				args->eb_split = SPLIT_RAW;
+				break;
+			case 'r':
+				i = str_to_num(optarg);
+				if (i < UBI_MAX_VOLUMES)
+					args->vols[str_to_num(optarg)] = 1;
+				else {
+					ERR_MSG("volume-id out of bounds\n");
+					return -1;
+				}
+				break;
+			case 'v':
+				if (args->vol_split != SPLIT_RAW)
+					args->vol_split = SPLIT_DATA;
+				break;
+			case 'V':
+				args->vol_split = SPLIT_RAW;
+				break;
+			case '?': /* help */
+				fprintf(stderr,
+					"Usage: unubi [OPTION...] "
+					"image-file\n");
+				fprintf(stderr, "%s", doc);
+				fprintf(stderr, "%s", optionsstr);
+				fprintf(stderr,
+					"\nReport bugs to %s\n", CONTACT);
+				exit(0);
+				break;
+			case 'J':
+				fprintf(stderr, "%s\n", VERSION);
+				exit(0);
+				break;
+			default:
+				fprintf(stderr, "%s", usage);
+				exit(-1);
+		}
+	}
+
+	if (optind < argc)
+		args->img_path = argv[optind++];
+	return 0;
+}
+
+
+/**
+ * counts the number of indicies which are flagged in full_array;
+ * full_array is an array of flags (1/0);
+ **/
+static size_t
+count_set(uint32_t *full_array, size_t full_len)
+{
+	size_t count, i;
+
+	if (full_array == NULL)
+		return 0;
+
+	for (i = 0, count = 0; i < full_len; i++)
+		if (full_array[i] != 0)
+			count++;
+
+	return count;
+}
+
+
+/**
+ * generates coll_array from full_array;
+ * full_array is an array of flags (1/0);
+ * coll_array is an array of the indicies in full_array which are flagged (1);
+ **/
+static size_t
+collapse(uint32_t *full_array, size_t full_len,
+	 uint32_t *coll_array, size_t coll_len)
+{
+	size_t i, j;
+
+	if ((full_array == NULL) || (coll_array == NULL))
+		return 0;
+
+	for (i = 0, j = 0; (i < full_len) && (j < coll_len); i++)
+		if (full_array[i] != 0) {
+			coll_array[j] = i;
+			j++;
+		}
+
+	return j;
+}
+
+
+/**
+ * header_crc: calculate the crc of EITHER a eb_hdr or vid_hdr
+ * one of the first to args MUST be NULL, the other is the header
+ *	to caculate the crc on
+ * always returns 0
+ **/
+static int
+header_crc(struct ubi_ec_hdr *ebh, struct ubi_vid_hdr *vidh, uint32_t *ret_crc)
+{
+	uint32_t crc = UBI_CRC32_INIT;
+
+	if (ret_crc == NULL)
+		return 0;
+
+	if ((ebh != NULL) && (vidh == NULL))
+		crc = clc_crc32(crc32_table, crc, ebh, UBI_EC_HDR_SIZE_CRC);
+	else if ((ebh == NULL) && (vidh != NULL))
+		crc = clc_crc32(crc32_table, crc, vidh, UBI_VID_HDR_SIZE_CRC);
+	else
+		return 0;
+
+	*ret_crc = crc;
+	return 0;
+}
+
+
+/**
+ * data_crc: save the FILE* position, calculate the crc over a span,
+ *	reset the position
+ * returns non-zero when EOF encountered
+ **/
+static int
+data_crc(FILE* fpin, size_t length, uint32_t *ret_crc)
+{
+	int rc;
+	size_t i;
+	char buf[length];
+	uint32_t crc;
+	fpos_t start;
+
+	rc = fgetpos(fpin, &start);
+	if (rc < 0)
+		return -1;
+
+	for (i = 0; i < length; i++) {
+		int c = fgetc(fpin);
+		if (c == EOF) {
+			ERR_MSG("unexpected EOF\n");
+			return -1;
+		}
+		buf[i] = (char)c;
+	}
+
+	rc = fsetpos(fpin, &start);
+	if (rc < 0)
+		return -1;
+
+	crc = clc_crc32(crc32_table, UBI_CRC32_INIT, buf, length);
+	*ret_crc = crc;
+	return 0;
+}
+
+
+/**
+ * reads data of size len from fpin and writes it to path
+ **/
+static int
+extract_data(FILE* fpin, size_t len, const char *path)
+{
+	int rc;
+	size_t i;
+	FILE* fpout;
+
+	rc = 0;
+	fpout = NULL;
+
+	fpout = fopen(path, "wb");
+	if (fpout == NULL) {
+		ERR_MSG("couldn't open file for writing: %s\n", path);
+		rc = -1;
+		goto err;
+	}
+
+	for (i = 0; i < len; i++) {
+		int c = fgetc(fpin);
+		if (c == EOF) {
+			ERR_MSG("unexpected EOF while writing: %s\n", path);
+			rc = -2;
+			goto err;
+		}
+		c = fputc(c, fpout);
+		if (c == EOF) {
+			ERR_MSG("couldn't write: %s\n", path);
+			rc = -3;
+			goto err;
+		}
+	}
+
+ err:
+	if (fpout != NULL)
+		fclose(fpout);
+	return rc;
+}
+
+
+/**
+ * using eb chain, tries to rebuild the data of volume at vol_id, or for all
+ * the known volumes, if vol_id is NULL;
+ **/
+static int
+rebuild_volume(FILE* fpin, uint32_t *vol_id, eb_info_t *head, const char* path)
+{
+	char filename[MAXPATH];
+	int rc;
+	uint32_t vol, num;
+	FILE* fpout;
+	eb_info_t cur;
+
+	rc = 0;
+
+	if ((fpin == NULL) || (head == NULL) || (*head == NULL))
+		return 0;
+
+	/* when vol_id is null, then do all  */
+	if (vol_id == NULL) {
+		cur = *head;
+		vol = ubi32_to_cpu(cur->inner.vol_id);
+	}
+	else {
+		vol = *vol_id;
+		eb_chain_position(head, vol, NULL, &cur);
+		if (cur == NULL) {
+			ERR_MSG("no valid volume %d was found\n", vol);
+			return -1;
+		}
+	}
+
+	num = 0;
+	snprintf(filename, MAXPATH, FN_VOLWH, path, vol);
+	fpout = fopen(filename, "wb");
+	if (fpout == NULL) {
+		ERR_MSG("couldn't open file for writing: %s\n", filename);
+		return -1;
+	}
+
+	while (cur != NULL) {
+		size_t i;
+
+		if (ubi32_to_cpu(cur->inner.vol_id) != vol) {
+			/* close out file */
+			fclose(fpout);
+
+			/* only stay around if that was the only volume */
+			if (vol_id != NULL)
+				goto out;
+
+			/* begin with next */
+			vol = ubi32_to_cpu(cur->inner.vol_id);
+			num = 0;
+			snprintf(filename, MAXPATH, FN_VOLWH, path, vol);
+			fpout = fopen(filename, "wb");
+			if (fpout == NULL) {
+				ERR_MSG("couldn't open file for writing: %s\n",
+					filename);
+				return -1;
+			}
+		}
+
+		if (ubi32_to_cpu(cur->inner.lnum) != num) {
+			ERR_MSG("missing valid block %d for volume %d\n",
+				num, vol);
+		}
+
+		rc = fsetpos(fpin, &(cur->eb_top));
+		if (rc < 0)
+			goto out;
+		fseek(fpin, ubi32_to_cpu(cur->outer.data_offset), SEEK_CUR);
+
+		for (i = 0; i < ubi32_to_cpu(cur->inner.data_size); i++) {
+			int c = fgetc(fpin);
+			if (c == EOF) {
+				ERR_MSG("unexpected EOF while writing: %s\n",
+					filename);
+				rc = -2;
+				goto out;
+			}
+			c = fputc(c, fpout);
+			if (c == EOF) {
+				ERR_MSG("couldn't write: %s\n", filename);
+				rc = -3;
+				goto out;
+			}
+		}
+
+		cur = cur->next;
+		num++;
+	}
+
+ out:
+	if (vol_id == NULL)
+		fclose(fpout);
+	return rc;
+}
+
+
+/**
+ * traverses FILE* trying to load complete, valid and accurate header data
+ * into the eb chain;
+ **/
+static int
+unubi_volumes(FILE* fpin, uint32_t *vols, size_t vc, struct args *a)
+{
+	char filename[MAXPATH + 1];
+	char reason[MAXPATH + 1];
+	int rc;
+	size_t i, count;
+	/* relations:
+	 * cur ~ head
+	 * next ~ first */
+	eb_info_t head, cur, first, next;
+	eb_info_t *next_ptr;
+
+	rc = 0;
+	count = 0;
+	head = NULL;
+	first = NULL;
+	next = NULL;
+	cur = malloc(sizeof(*cur));
+	if (cur == NULL) {
+		ERR_MSG("out of memory\n");
+		rc = -ENOMEM;
+		goto err;
+	}
+	memset(cur, 0, sizeof(*cur));
+
+	fgetpos(fpin, &(cur->eb_top));
+	while (1) {
+		const char *raw_path;
+		uint32_t crc;
+
+		memset(filename, 0, MAXPATH + 1);
+		memset(reason, 0, MAXPATH + 1);
+
+		/* in case of an incomplete ec header */
+		raw_path = FN_INVAL;
+
+		/* read erasecounter header */
+		rc = fread(&cur->outer, 1, sizeof(cur->outer), fpin);
+		if (rc == 0)
+			goto out; /* EOF */
+		if (rc != sizeof(cur->outer)) {
+			ERR_MSG("reading ec-hdr failed rc=%d\n", rc);
+			rc = -1;
+			goto err;
+		}
+
+		/* check erasecounter header magic */
+		if (ubi32_to_cpu(cur->outer.magic) != UBI_EC_HDR_MAGIC) {
+			snprintf(reason, MAXPATH, ".invalid.ec_magic");
+			goto invalid;
+		}
+
+		/* check erasecounter header crc */
+		header_crc(&(cur->outer), NULL, &crc);
+
+		if (ubi32_to_cpu(cur->outer.hdr_crc) != crc) {
+			snprintf(reason, MAXPATH, ".invalid.ec_hdr_crc");
+			goto invalid;
+		}
+
+		/* read volume id header */
+		rc = fsetpos(fpin, &(cur->eb_top));
+		if (rc != 0)
+			goto err;
+		fseek(fpin, ubi32_to_cpu(cur->outer.vid_hdr_offset), SEEK_CUR);
+
+		/* read erasecounter header */
+		rc = fread(&cur->inner, 1, sizeof(cur->inner), fpin);
+		if (rc == 0)
+			goto out; /* EOF */
+		if (rc != sizeof(cur->inner)) {
+			ERR_MSG("reading vid-hdr failed rc=%d\n", rc);
+			rc = -1;
+			goto err;
+		}
+
+		/* empty? */
+		if (ubi32_to_cpu(cur->inner.magic) == 0xffffffff) {
+			snprintf(reason, MAXPATH, ".empty");
+			goto invalid;
+		}
+
+		/* vol_id should be in bounds */
+		if ((ubi32_to_cpu(cur->inner.vol_id) >= UBI_MAX_VOLUMES) &&
+		    (ubi32_to_cpu(cur->inner.vol_id) <
+		     UBI_INTERNAL_VOL_START)) {
+			snprintf(reason, MAXPATH, ".invalid");
+			goto invalid;
+		} else
+			raw_path = FN_NSURE;
+
+		/* check volume id header magic */
+		if (ubi32_to_cpu(cur->inner.magic) != UBI_VID_HDR_MAGIC) {
+			snprintf(reason, MAXPATH, ".invalid.vid_magic");
+			goto invalid;
+		}
+
+		/* check volume id header crc */
+		header_crc(NULL, &(cur->inner), &crc);
+		if (ubi32_to_cpu(cur->inner.hdr_crc) != crc) {
+			snprintf(reason, MAXPATH, ".invalid.vid_hdr_crc");
+			goto invalid;
+		}
+
+		/* check data crc */
+		rc = data_crc(fpin, ubi32_to_cpu(cur->inner.data_size), &crc);
+		if (rc < 0)
+			goto err;
+		if (ubi32_to_cpu(cur->inner.data_crc) != crc) {
+			snprintf(reason, MAXPATH, ".invalid.data_crc");
+			goto invalid;
+		}
+
+		/* enlist this vol, it's valid */
+		raw_path = FN_VALID;
+		cur->linear = count;
+		rc = eb_chain_insert(&head, cur);
+		if (rc < 0) {
+			if (rc == -ENOMEM) {
+				ERR_MSG("out of memory\n");
+				goto err;
+			}
+			ERR_MSG("unknown and unexpected error, please contact "
+				CONTACT "\n");
+			goto err;
+		}
+
+		if (a->vol_split) {
+			size_t size = 0;
+
+			rc = fsetpos(fpin, &(cur->eb_top));
+			if (rc != 0)
+				goto err;
+
+			if (a->vol_split == SPLIT_DATA) {
+				/* write only data section */
+				size = ubi32_to_cpu(cur->inner.data_size);
+				fseek(fpin,
+				      ubi32_to_cpu(cur->outer.data_offset),
+				      SEEK_CUR);
+			}
+			else if (a->vol_split == SPLIT_RAW)
+				/* write entire eraseblock */
+				size = a->bsize;
+
+			snprintf(filename, MAXPATH, FN_VOLSP,
+				 a->odir_path,
+				 ubi32_to_cpu(cur->inner.vol_id),
+				 ubi32_to_cpu(cur->inner.lnum),
+				 ubi32_to_cpu(cur->inner.leb_ver), count);
+			rc = extract_data(fpin, size, filename);
+			if (rc < 0)
+				goto err;
+		}
+
+ invalid:
+		if (a->eb_split) {
+			/* jump to top of block */
+			rc = fsetpos(fpin, &(cur->eb_top));
+			if (rc != 0)
+				goto err;
+
+			if (strcmp(raw_path, FN_INVAL) == 0)
+				snprintf(filename, MAXPATH, raw_path,
+					 a->odir_path, count, reason);
+			else
+				snprintf(filename, MAXPATH, raw_path,
+					 a->odir_path,
+					 count,
+					 ubi32_to_cpu(cur->inner.vol_id),
+					 ubi32_to_cpu(cur->inner.lnum),
+					 ubi32_to_cpu(cur->inner.leb_ver),
+					 reason);
+
+			rc = extract_data(fpin, a->bsize, filename);
+			if (rc < 0)
+				goto err;
+		}
+
+		/* append to simple linked list */
+		if (first == NULL)
+			next_ptr = &first;
+		else
+			next_ptr = &next->next;
+
+		*next_ptr = malloc(sizeof(**next_ptr));
+		if (*next_ptr == NULL) {
+			ERR_MSG("out of memory\n");
+			rc = -ENOMEM;
+			goto err;
+		}
+		memset(*next_ptr, 0, sizeof(**next_ptr));
+
+		next = *next_ptr;
+		memcpy(next, cur, sizeof(*next));
+		next->next = NULL;
+
+		count++;
+		rc = fsetpos(fpin, &(cur->eb_top));
+		if (rc != 0)
+			goto err;
+		fseek(fpin, a->bsize, SEEK_CUR);
+		memset(cur, 0, sizeof(*cur));
+
+		fgetpos(fpin, &(cur->eb_top));
+	}
+
+ out:
+	for (i = 0; i < vc; i++) {
+		rc = rebuild_volume(fpin, &vols[i], &head, a->odir_path);
+		if (rc < 0)
+			goto err;
+	}
+
+	/* if there were no volumes specified, rebuild them all,
+	 * UNLESS eb_ or vol_ split or analyze was specified */
+	if ((vc == 0) && (!a->eb_split) && (!a->vol_split) && (!a->analyze)) {
+		rc = rebuild_volume(fpin, NULL, &head, a->odir_path);
+		if (rc < 0)
+			goto err;
+	}
+
+ err:
+	free(cur);
+
+	if (a->analyze)
+		unubi_analyze(&head, first, a->odir_path);
+	eb_chain_destroy(&head);
+	eb_chain_destroy(&first);
+
+	return rc;
+}
+
+
+/**
+ * handles command line arguments, then calls unubi_volumes
+ **/
+int
+main(int argc, char *argv[])
+{
+	int rc, free_a_odir;
+	size_t vols_len;
+	uint32_t *vols;
+	FILE* fpin;
+	struct args a;
+
+	rc = 0;
+	free_a_odir = 0;
+	vols_len = 0;
+	vols = NULL;
+	fpin = NULL;
+	init_crc32_table(crc32_table);
+
+	/* setup struct args a */
+	memset(&a, 0, sizeof(a));
+	a.bsize = 128 * KIB;
+	a.vols = malloc(sizeof(*a.vols) * UBI_MAX_VOLUMES);
+	if (a.vols == NULL) {
+		ERR_MSG("out of memory\n");
+		rc = ENOMEM;
+		goto err;
+	}
+	memset(a.vols, 0, sizeof(*a.vols) * UBI_MAX_VOLUMES);
+
+	/* parse args and check for validity */
+	parse_opt(argc, argv, &a);
+	if (a.img_path == NULL) {
+		ERR_MSG("no image file specified\n");
+		rc = EINVAL;
+		goto err;
+	}
+	else if (a.odir_path == NULL) {
+		char *ptr;
+		int len;
+
+		ptr = strrchr(a.img_path, '/');
+		if (ptr == NULL)
+			ptr = a.img_path;
+		else
+			ptr++;
+
+		len = strlen(DIR_FMT) + strlen(ptr);
+		free_a_odir = 1;
+		a.odir_path = malloc(sizeof(*a.odir_path) * len);
+		if (a.odir_path == NULL) {
+			ERR_MSG("out of memory\n");
+			rc = ENOMEM;
+			goto err;
+		}
+		snprintf(a.odir_path, len, DIR_FMT, ptr);
+	}
+
+	fpin = fopen(a.img_path, "rb");
+	if (fpin == NULL) {
+		ERR_MSG("couldn't open file for reading: "
+			"%s\n", a.img_path);
+		rc = EINVAL;
+		goto err;
+	}
+
+	rc = mkdir(a.odir_path, 0777);
+	if ((rc < 0) && (errno != EEXIST)) {
+		ERR_MSG("couldn't create ouput directory: "
+			"%s\n", a.odir_path);
+		rc = -rc;
+		goto err;
+	}
+
+	/* fill in vols array */
+	vols_len = count_set(a.vols, UBI_MAX_VOLUMES);
+	if (vols_len > 0) {
+		vols = malloc(sizeof(*vols) * vols_len);
+		if (vols == NULL) {
+			ERR_MSG("out of memory\n");
+			rc = ENOMEM;
+			goto err;
+		}
+		collapse(a.vols, UBI_MAX_VOLUMES, vols, vols_len);
+	}
+
+	/* unubi volumes */
+	rc = unubi_volumes(fpin, vols, vols_len, &a);
+	if (rc < 0) {
+		ERR_MSG("error encountered while working on image file: "
+			"%s\n", a.img_path);
+		rc = -rc;
+		goto err;
+	}
+
+ err:
+	free(a.vols);
+	if (free_a_odir != 0)
+		free(a.odir_path);
+	if (fpin != NULL)
+		fclose(fpin);
+	if (vols_len > 0)
+		free(vols);
+	return rc;
+}