Adding upstream version 2.38.1.upstream/2.38.1upstream

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

1 files changed, 797 insertions, 0 deletions

diff --git a/libfdisk/src/table.c b/libfdisk/src/table.c
new file mode 100644
index 0000000..84c60d4
--- /dev/null
+++ b/libfdisk/src/table.c
@@ -0,0 +1,797 @@
+
+#include "fdiskP.h"
+
+/**
+ * SECTION: table
+ * @title: Table
+ * @short_description: container for fdisk partitions
+ *
+ * The fdisk_table is simple container for fdisk_partitions. The table is no
+ * directly connected to label data (partition table), and table changes don't
+ * affect in-memory or on-disk data.
+ */
+
+/**
+ * fdisk_new_table:
+ *
+ * The table is a container for struct fdisk_partition entries. The container
+ * does not have any real connection with label (partition table) and with
+ * real on-disk data.
+ *
+ * Returns: newly allocated table struct.
+ */
+struct fdisk_table *fdisk_new_table(void)
+{
+	struct fdisk_table *tb = NULL;
+
+	tb = calloc(1, sizeof(*tb));
+	if (!tb)
+		return NULL;
+
+	DBG(TAB, ul_debugobj(tb, "alloc"));
+	tb->refcount = 1;
+	INIT_LIST_HEAD(&tb->parts);
+	return tb;
+}
+
+/**
+ * fdisk_reset_table:
+ * @tb: tab pointer
+ *
+ * Removes all entries (partitions) from the table. The partitions with zero
+ * reference count will be deallocated. This function does not modify partition
+ * table.
+ *
+ * Returns: 0 on success or negative number in case of error.
+ */
+int fdisk_reset_table(struct fdisk_table *tb)
+{
+	if (!tb)
+		return -EINVAL;
+
+	DBG(TAB, ul_debugobj(tb, "reset"));
+
+	while (!list_empty(&tb->parts)) {
+		struct fdisk_partition *pa = list_entry(tb->parts.next,
+				                  struct fdisk_partition, parts);
+		fdisk_table_remove_partition(tb, pa);
+	}
+
+	tb->nents = 0;
+	return 0;
+}
+
+/**
+ * fdisk_ref_table:
+ * @tb: table pointer
+ *
+ * Increments reference counter.
+ */
+void fdisk_ref_table(struct fdisk_table *tb)
+{
+	if (tb)
+		tb->refcount++;
+}
+
+/**
+ * fdisk_unref_table:
+ * @tb: table pointer
+ *
+ * Descrements reference counter, on zero the @tb is automatically
+ * deallocated.
+ */
+void fdisk_unref_table(struct fdisk_table *tb)
+{
+	if (!tb)
+		return;
+
+	tb->refcount--;
+	if (tb->refcount <= 0) {
+		fdisk_reset_table(tb);
+
+		DBG(TAB, ul_debugobj(tb, "free"));
+		free(tb);
+	}
+}
+
+/**
+ * fdisk_table_is_empty:
+ * @tb: pointer to tab
+ *
+ * Returns: 1 if the table is without filesystems, or 0.
+ */
+int fdisk_table_is_empty(struct fdisk_table *tb)
+{
+	return tb == NULL || list_empty(&tb->parts) ? 1 : 0;
+}
+
+/**
+ * fdisk_table_get_nents:
+ * @tb: pointer to tab
+ *
+ * Returns: number of entries in table.
+ */
+size_t fdisk_table_get_nents(struct fdisk_table *tb)
+{
+	return tb ? tb->nents : 0;
+}
+
+/**
+ * fdisk_table_next_partition:
+ * @tb: tab pointer
+ * @itr: iterator
+ * @pa: returns the next tab entry
+ *
+ * Returns: 0 on success, negative number in case of error or 1 at the end of list.
+ *
+ * Example:
+ * <informalexample>
+ *   <programlisting>
+ *	while(fdisk_table_next_partition(tb, itr, &pa) == 0) {
+ *		...
+ *	}
+ *   </programlisting>
+ * </informalexample>
+ */
+int fdisk_table_next_partition(
+			struct fdisk_table *tb,
+			struct fdisk_iter *itr,
+			struct fdisk_partition **pa)
+{
+	int rc = 1;
+
+	if (!tb || !itr || !pa)
+		return -EINVAL;
+	*pa = NULL;
+
+	if (!itr->head)
+		FDISK_ITER_INIT(itr, &tb->parts);
+	if (itr->p != itr->head) {
+		FDISK_ITER_ITERATE(itr, *pa, struct fdisk_partition, parts);
+		rc = 0;
+	}
+
+	return rc;
+}
+
+/**
+ * fdisk_table_get_partition:
+ * @tb: tab pointer
+ * @n: number of entry in table
+ *
+ * Returns: n-th entry from table or NULL
+ */
+struct fdisk_partition *fdisk_table_get_partition(
+			struct fdisk_table *tb,
+			size_t n)
+{
+	struct fdisk_partition *pa = NULL;
+	struct fdisk_iter itr;
+
+	if (!tb)
+		return NULL;
+
+	fdisk_reset_iter(&itr, FDISK_ITER_FORWARD);
+
+	while (fdisk_table_next_partition(tb, &itr, &pa) == 0) {
+		if (n == 0)
+			return pa;
+		n--;
+	}
+
+	return NULL;
+}
+
+/**
+ * fdisk_table_get_partition_by_partno:
+ * @tb: tab pointer
+ * @partno: partition number
+ *
+ * Returns: partition with @partno or NULL.
+ */
+struct fdisk_partition *fdisk_table_get_partition_by_partno(
+			struct fdisk_table *tb,
+			size_t partno)
+{
+	struct fdisk_partition *pa = NULL;
+	struct fdisk_iter itr;
+
+	if (!tb)
+		return NULL;
+
+	fdisk_reset_iter(&itr, FDISK_ITER_FORWARD);
+
+	while (fdisk_table_next_partition(tb, &itr, &pa) == 0) {
+		if (pa->partno == partno)
+			return pa;
+	}
+
+	return NULL;
+}
+
+/**
+ * fdisk_table_add_partition
+ * @tb: tab pointer
+ * @pa: new entry
+ *
+ * Adds a new entry to table and increment @pa reference counter. Don't forget to
+ * use fdisk_unref_partition() after fdisk_table_add_partition() if you want to keep
+ * the @pa referenced by the table only.
+ *
+ * Returns: 0 on success or negative number in case of error.
+ */
+int fdisk_table_add_partition(struct fdisk_table *tb, struct fdisk_partition *pa)
+{
+	if (!tb || !pa)
+		return -EINVAL;
+
+	if (!list_empty(&pa->parts))
+		return -EBUSY;
+
+	fdisk_ref_partition(pa);
+	list_add_tail(&pa->parts, &tb->parts);
+	tb->nents++;
+
+	DBG(TAB, ul_debugobj(tb, "add entry %p [start=%ju, end=%ju, size=%ju, %s %s %s]",
+			pa,
+			(uintmax_t) fdisk_partition_get_start(pa),
+			fdisk_partition_has_end(pa) ? (uintmax_t) fdisk_partition_get_end(pa) : 0,
+			fdisk_partition_has_size(pa) ? (uintmax_t) fdisk_partition_get_size(pa) : 0,
+			fdisk_partition_is_freespace(pa) ? "freespace" : "",
+			fdisk_partition_is_nested(pa)    ? "nested"    : "",
+			fdisk_partition_is_container(pa) ? "container" : "primary"));
+	return 0;
+}
+
+/* inserts @pa after @poz */
+static int table_insert_partition(
+			struct fdisk_table *tb,
+			struct fdisk_partition *poz,
+			struct fdisk_partition *pa)
+{
+	assert(tb);
+	assert(pa);
+
+	fdisk_ref_partition(pa);
+	if (poz)
+		list_add(&pa->parts, &poz->parts);
+	else
+		list_add(&pa->parts, &tb->parts);
+	tb->nents++;
+
+	DBG(TAB, ul_debugobj(tb, "insert entry %p pre=%p [start=%ju, end=%ju, size=%ju, %s %s %s]",
+			pa, poz ? poz : NULL,
+			(uintmax_t) fdisk_partition_get_start(pa),
+			(uintmax_t) fdisk_partition_get_end(pa),
+			(uintmax_t) fdisk_partition_get_size(pa),
+			fdisk_partition_is_freespace(pa) ? "freespace" : "",
+			fdisk_partition_is_nested(pa)    ? "nested"    : "",
+			fdisk_partition_is_container(pa) ? "container" : ""));
+	return 0;
+}
+
+/**
+ * fdisk_table_remove_partition
+ * @tb: tab pointer
+ * @pa: new entry
+ *
+ * Removes the @pa from the table and de-increment reference counter of the @pa. The
+ * partition with zero reference counter will be deallocated. Don't forget to use
+ * fdisk_ref_partition() before call fdisk_table_remove_partition() if you want
+ * to use @pa later.
+ *
+ * Returns: 0 on success or negative number in case of error.
+ */
+int fdisk_table_remove_partition(struct fdisk_table *tb, struct fdisk_partition *pa)
+{
+	if (!tb || !pa)
+		return -EINVAL;
+
+	DBG(TAB, ul_debugobj(tb, "remove entry %p", pa));
+	list_del(&pa->parts);
+	INIT_LIST_HEAD(&pa->parts);
+
+	fdisk_unref_partition(pa);
+	tb->nents--;
+
+	return 0;
+}
+
+/**
+ * fdisk_get_partitions
+ * @cxt: fdisk context
+ * @tb: returns table
+ *
+ * This function adds partitions from disklabel to @table, it allocates a new
+ * table if @table points to NULL.
+ *
+ * Returns: 0 on success, otherwise, a corresponding error.
+ */
+int fdisk_get_partitions(struct fdisk_context *cxt, struct fdisk_table **tb)
+{
+	size_t i;
+
+	if (!cxt || !cxt->label || !tb)
+		return -EINVAL;
+	if (!cxt->label->op->get_part)
+		return -ENOSYS;
+
+	DBG(CXT, ul_debugobj(cxt, " -- get table --"));
+
+	if (!*tb && !(*tb = fdisk_new_table()))
+		return -ENOMEM;
+
+	for (i = 0; i < cxt->label->nparts_max; i++) {
+		struct fdisk_partition *pa = NULL;
+
+		if (fdisk_get_partition(cxt, i, &pa) != 0)
+			continue;
+		if (fdisk_partition_is_used(pa))
+			fdisk_table_add_partition(*tb, pa);
+		fdisk_unref_partition(pa);
+	}
+
+	return 0;
+}
+
+void fdisk_debug_print_table(struct fdisk_table *tb)
+{
+	struct fdisk_iter itr;
+	struct fdisk_partition *pa;
+
+	fdisk_reset_iter(&itr, FDISK_ITER_FORWARD);
+	while (fdisk_table_next_partition(tb, &itr, &pa) == 0)
+		ul_debugobj(tb, "partition %p [partno=%zu, start=%ju, end=%ju, size=%ju%s%s%s] ",
+			    pa, pa->partno,
+			    (uintmax_t) fdisk_partition_get_start(pa),
+			    (uintmax_t) fdisk_partition_get_end(pa),
+			    (uintmax_t) fdisk_partition_get_size(pa),
+			    fdisk_partition_is_nested(pa) ? " nested" : "",
+			    fdisk_partition_is_freespace(pa) ? " freespace" : "",
+			    fdisk_partition_is_container(pa) ? " container" : "");
+
+}
+
+
+typedef	int (*fdisk_partcmp_t)(struct fdisk_partition *, struct fdisk_partition *);
+
+static int cmp_parts_wrapper(struct list_head *a, struct list_head *b, void *data)
+{
+	struct fdisk_partition *pa = list_entry(a, struct fdisk_partition, parts),
+			       *pb = list_entry(b, struct fdisk_partition, parts);
+
+	fdisk_partcmp_t cmp = (fdisk_partcmp_t) data;
+
+	return cmp(pa, pb);
+}
+
+
+/**
+ * fdisk_table_sort_partitions:
+ * @tb: table
+ * @cmp: compare function
+ *
+ * Sort partition in the table.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int fdisk_table_sort_partitions(struct fdisk_table *tb,
+			int (*cmp)(struct fdisk_partition *,
+				   struct fdisk_partition *))
+{
+	if (!tb)
+		return -EINVAL;
+
+	/*
+	DBG(TAB, ul_debugobj(tb, "Before sort:"));
+	ON_DBG(TAB, fdisk_debug_print_table(tb));
+	*/
+
+	list_sort(&tb->parts, cmp_parts_wrapper, (void *) cmp);
+
+	/*
+	DBG(TAB, ul_debugobj(tb, "After sort:"));
+	ON_DBG(TAB, fdisk_debug_print_table(tb));
+	*/
+
+	return 0;
+}
+
+/* allocates a new freespace description */
+static int new_freespace(struct fdisk_context *cxt,
+			 fdisk_sector_t start,
+			 fdisk_sector_t end,
+			 struct fdisk_partition *parent,
+			 struct fdisk_partition **pa)
+{
+	fdisk_sector_t aligned_start, size;
+
+	assert(cxt);
+	assert(pa);
+
+	*pa = NULL;
+
+	if (start == end)
+		return 0;
+
+	assert(start >= cxt->first_lba);
+	assert(end);
+	assert(end > start);
+
+	aligned_start = fdisk_align_lba_in_range(cxt, start, start, end);
+	size = end - aligned_start + 1ULL;
+
+	if (size == 0) {
+		DBG(TAB, ul_debug("ignore freespace (aligned size is zero)"));
+		return 0;
+	}
+
+	*pa = fdisk_new_partition();
+	if (!*pa)
+		return -ENOMEM;
+
+	(*pa)->freespace = 1;
+	(*pa)->start = aligned_start;
+	(*pa)->size = size;
+
+	if (parent)
+		(*pa)->parent_partno = parent->partno;
+	return 0;
+}
+
+/* add freespace description to the right place within @tb */
+static int table_add_freespace(
+			struct fdisk_context *cxt,
+			struct fdisk_table *tb,
+			fdisk_sector_t start,
+			fdisk_sector_t end,
+			struct fdisk_partition *parent)
+{
+	struct fdisk_partition *pa, *x, *real_parent = NULL, *best = NULL;
+	struct fdisk_iter itr;
+	int rc = 0;
+
+	assert(tb);
+
+	rc = new_freespace(cxt, start, end, parent, &pa);
+	if (rc)
+		return -ENOMEM;
+	if (!pa)
+		return 0;
+
+	assert(fdisk_partition_has_start(pa));
+	assert(fdisk_partition_has_end(pa));
+
+	DBG(TAB, ul_debugobj(tb, "adding freespace"));
+
+	fdisk_reset_iter(&itr, FDISK_ITER_FORWARD);
+	if (parent && fdisk_partition_has_partno(parent)) {
+		while (fdisk_table_next_partition(tb, &itr, &x) == 0) {
+			if (!fdisk_partition_has_partno(x))
+				continue;
+			if (x->partno == parent->partno) {
+				real_parent = x;
+				break;
+			}
+		}
+		if (!real_parent) {
+			DBG(TAB, ul_debugobj(tb, "not found freespace parent (partno=%zu)",
+					parent->partno));
+			fdisk_reset_iter(&itr, FDISK_ITER_FORWARD);
+		}
+	}
+
+	while (fdisk_table_next_partition(tb, &itr, &x) == 0) {
+		fdisk_sector_t the_end, best_end = 0;
+
+		if (!fdisk_partition_has_end(x))
+			continue;
+
+		the_end = fdisk_partition_get_end(x);
+		if (best)
+			best_end = fdisk_partition_get_end(best);
+
+		if (the_end < pa->start && (!best || best_end < the_end))
+			best = x;
+	}
+
+	if (!best && real_parent)
+		best = real_parent;
+	rc = table_insert_partition(tb, best, pa);
+
+	fdisk_unref_partition(pa);
+
+	DBG(TAB, ul_debugobj(tb, "adding freespace DONE [rc=%d]", rc));
+	return rc;
+}
+
+/* analyze @cont(ainer) in @parts and add all detected freespace into @tb, note
+ * that @parts has to be sorted by partition starts */
+static int check_container_freespace(struct fdisk_context *cxt,
+				     struct fdisk_table *parts,
+				     struct fdisk_table *tb,
+				     struct fdisk_partition *cont)
+{
+	struct fdisk_iter itr;
+	struct fdisk_partition *pa;
+	fdisk_sector_t x, last, grain, lastplusoff;
+	int rc = 0;
+
+	assert(cxt);
+	assert(parts);
+	assert(tb);
+	assert(cont);
+	assert(fdisk_partition_has_start(cont));
+
+	DBG(TAB, ul_debugobj(tb, "analyze container 0x%p", cont));
+
+	last = fdisk_partition_get_start(cont);
+	grain = cxt->grain > cxt->sector_size ?	cxt->grain / cxt->sector_size : 1;
+	fdisk_reset_iter(&itr, FDISK_ITER_FORWARD);
+
+	DBG(CXT, ul_debugobj(cxt, "initialized:  last=%ju, grain=%ju",
+	                     (uintmax_t)last,  (uintmax_t)grain));
+
+	while (fdisk_table_next_partition(parts, &itr, &pa) == 0) {
+
+		DBG(CXT, ul_debugobj(cxt, "partno=%zu, start=%ju",
+		                     pa->partno, (uintmax_t)pa->start));
+
+		if (!pa->used || !fdisk_partition_is_nested(pa)
+			      || !fdisk_partition_has_start(pa))
+			continue;
+
+		DBG(CXT, ul_debugobj(cxt, "freespace container analyze: partno=%zu, start=%ju, end=%ju",
+					pa->partno,
+					(uintmax_t) fdisk_partition_get_start(pa),
+					(uintmax_t) fdisk_partition_get_end(pa)));
+
+		lastplusoff = last + cxt->first_lba;
+		if (pa->start > lastplusoff && pa->start - lastplusoff > grain)
+			rc = table_add_freespace(cxt, tb, lastplusoff, pa->start, cont);
+		if (rc)
+			goto done;
+		last = fdisk_partition_get_end(pa);
+	}
+
+	/* free-space remaining in extended partition */
+	x = fdisk_partition_get_start(cont) + fdisk_partition_get_size(cont) - 1;
+	lastplusoff = last + cxt->first_lba;
+	if (lastplusoff < x && x - lastplusoff > grain) {
+		DBG(TAB, ul_debugobj(tb, "add remaining space in container 0x%p", cont));
+		rc = table_add_freespace(cxt, tb, lastplusoff, x, cont);
+	}
+
+done:
+	DBG(TAB, ul_debugobj(tb, "analyze container 0x%p DONE [rc=%d]", cont, rc));
+	return rc;
+}
+
+
+/**
+ * fdisk_get_freespaces
+ * @cxt: fdisk context
+ * @tb: returns table
+ *
+ * This function adds freespace (described by fdisk_partition) to @table, it
+ * allocates a new table if the @table points to NULL.
+ *
+ * Note that free space smaller than grain (see fdisk_get_grain_size()) is
+ * ignored.
+ *
+ * Returns: 0 on success, otherwise, a corresponding error.
+ */
+int fdisk_get_freespaces(struct fdisk_context *cxt, struct fdisk_table **tb)
+{
+	int rc = 0;
+	size_t nparts = 0;
+	fdisk_sector_t last, grain;
+	struct fdisk_table *parts = NULL;
+	struct fdisk_partition *pa;
+	struct fdisk_iter itr;
+
+	DBG(CXT, ul_debugobj(cxt, "-- get freespace --"));
+
+	if (!cxt || !cxt->label || !tb)
+		return -EINVAL;
+	if (!*tb && !(*tb = fdisk_new_table()))
+		return -ENOMEM;
+
+	rc = fdisk_get_partitions(cxt, &parts);
+	if (rc)
+		goto done;
+
+	fdisk_table_sort_partitions(parts, fdisk_partition_cmp_start);
+	fdisk_reset_iter(&itr, FDISK_ITER_FORWARD);
+	last = cxt->first_lba;
+	grain = cxt->grain > cxt->sector_size ?	cxt->grain / cxt->sector_size : 1;
+
+	DBG(CXT, ul_debugobj(cxt, "initialized:  last=%ju, grain=%ju",
+	                     (uintmax_t)last,  (uintmax_t)grain));
+
+	/* analyze gaps between partitions */
+	while (rc == 0 && fdisk_table_next_partition(parts, &itr, &pa) == 0) {
+
+		DBG(CXT, ul_debugobj(cxt, "partno=%zu, start=%ju",
+		                     pa->partno, (uintmax_t)pa->start));
+
+		if (!pa->used || pa->wholedisk || fdisk_partition_is_nested(pa)
+			      || !fdisk_partition_has_start(pa))
+			continue;
+		DBG(CXT, ul_debugobj(cxt, "freespace analyze: partno=%zu, start=%ju, end=%ju",
+					pa->partno,
+					(uintmax_t) fdisk_partition_get_start(pa),
+					(uintmax_t) fdisk_partition_get_end(pa)));
+
+		/* We ignore small free spaces (smaller than grain) to keep partitions
+		 * aligned, the exception is space before the first partition when
+		 * cxt->first_lba is aligned. */
+		if (last + grain < pa->start
+		    || (nparts == 0 &&
+		        (fdisk_align_lba(cxt, last, FDISK_ALIGN_UP) <
+			 pa->start))) {
+			rc = table_add_freespace(cxt, *tb,
+				last + (nparts == 0 ? 0 : 1),
+				pa->start - 1, NULL);
+		}
+		/* add gaps between logical partitions */
+		if (fdisk_partition_is_container(pa))
+			rc = check_container_freespace(cxt, parts, *tb, pa);
+
+		if (fdisk_partition_has_end(pa)) {
+			fdisk_sector_t pa_end = fdisk_partition_get_end(pa);
+			if (pa_end > last)
+				last = fdisk_partition_get_end(pa);
+		}
+		nparts++;
+	}
+
+	/* add free-space behind last partition to the end of the table (so
+	 * don't use table_add_freespace()) */
+	if (rc == 0 && last + grain < cxt->last_lba - 1) {
+		DBG(CXT, ul_debugobj(cxt, "freespace behind last partition detected"));
+		rc = new_freespace(cxt,
+			last + (last > cxt->first_lba || nparts ? 1 : 0),
+			cxt->last_lba, NULL, &pa);
+		if (pa) {
+			fdisk_table_add_partition(*tb, pa);
+			fdisk_unref_partition(pa);
+		}
+	}
+
+done:
+	fdisk_unref_table(parts);
+
+	DBG(CXT, ul_debugobj(cxt, "get freespace DONE [rc=%d]", rc));
+	return rc;
+}
+
+/**
+ * fdisk_table_wrong_order:
+ * @tb: table
+ *
+ * Returns: 1 of the table is not in disk order
+ */
+int fdisk_table_wrong_order(struct fdisk_table *tb)
+{
+	struct fdisk_partition *pa;
+	struct fdisk_iter itr;
+	fdisk_sector_t last = 0;
+
+	DBG(TAB, ul_debugobj(tb, "wrong older check"));
+
+	fdisk_reset_iter(&itr, FDISK_ITER_FORWARD);
+	while (tb && fdisk_table_next_partition(tb, &itr, &pa) == 0) {
+		if (!fdisk_partition_has_start(pa) || fdisk_partition_is_wholedisk(pa))
+			continue;
+		if (pa->start < last)
+			return 1;
+		last = pa->start;
+	}
+	return 0;
+}
+
+/**
+ * fdisk_apply_table:
+ * @cxt: context
+ * @tb: table
+ *
+ * Add partitions from table @tb to the in-memory disk label. See
+ * fdisk_add_partition(), fdisk_delete_all_partitions(). The partitions
+ * that does not define start (or does not follow the default start)
+ * are ignored.
+ *
+ * Returns: 0 on success, <0 on error.
+ */
+int fdisk_apply_table(struct fdisk_context *cxt, struct fdisk_table *tb)
+{
+	struct fdisk_partition *pa;
+	struct fdisk_iter itr;
+	int rc = 0;
+
+	assert(cxt);
+	assert(tb);
+
+	DBG(TAB, ul_debugobj(tb, "applying to context %p", cxt));
+
+	fdisk_reset_iter(&itr, FDISK_ITER_FORWARD);
+	while (tb && fdisk_table_next_partition(tb, &itr, &pa) == 0) {
+		if (!fdisk_partition_has_start(pa) && !pa->start_follow_default)
+			continue;
+		rc = fdisk_add_partition(cxt, pa, NULL);
+		if (rc)
+			break;
+	}
+
+	return rc;
+}
+
+int fdisk_diff_tables(struct fdisk_table *a, struct fdisk_table *b,
+		      struct fdisk_iter *itr,
+		      struct fdisk_partition **res, int *change)
+{
+	struct fdisk_partition *pa = NULL, *pb;
+	int rc = 1;
+
+	assert(itr);
+	assert(res);
+	assert(change);
+
+	DBG(TAB, ul_debugobj(a, "table diff [new table=%p]", b));
+
+	if (a && (itr->head == NULL || itr->head == &a->parts)) {
+		DBG(TAB, ul_debugobj(a, " scanning old table"));
+		do {
+			rc = fdisk_table_next_partition(a, itr, &pa);
+			if (rc != 0)
+				break;
+		} while (!fdisk_partition_has_partno(pa));
+	}
+
+	if (rc == 1 && b) {
+		DBG(TAB, ul_debugobj(a, " scanning new table"));
+		if (itr->head != &b->parts) {
+			DBG(TAB, ul_debugobj(a, "  initialize to TAB=%p", b));
+			fdisk_reset_iter(itr, FDISK_ITER_FORWARD);
+		}
+
+		while (fdisk_table_next_partition(b, itr, &pb) == 0) {
+			if (!fdisk_partition_has_partno(pb))
+				continue;
+			if (a == NULL ||
+			    fdisk_table_get_partition_by_partno(a, pb->partno) == NULL) {
+				DBG(TAB, ul_debugobj(a, " #%zu ADDED", pb->partno));
+				*change = FDISK_DIFF_ADDED;
+				*res = pb;
+				return 0;
+			}
+		}
+	}
+
+	if (rc) {
+		DBG(TAB, ul_debugobj(a, "table diff done [rc=%d]", rc));
+		return rc;	/* error or done */
+	}
+
+	pb = fdisk_table_get_partition_by_partno(b, pa->partno);
+
+	if (!pb) {
+		DBG(TAB, ul_debugobj(a, " #%zu REMOVED", pa->partno));
+		*change = FDISK_DIFF_REMOVED;
+		*res = pa;
+	} else if (pb->start != pa->start) {
+		DBG(TAB, ul_debugobj(a, " #%zu MOVED", pb->partno));
+		*change = FDISK_DIFF_MOVED;
+		*res = pb;
+	} else if (pb->size != pa->size) {
+		DBG(TAB, ul_debugobj(a, " #%zu RESIZED", pb->partno));
+		*change = FDISK_DIFF_RESIZED;
+		*res = pb;
+	} else {
+		DBG(TAB, ul_debugobj(a, " #%zu UNCHANGED", pb->partno));
+		*change = FDISK_DIFF_UNCHANGED;
+		*res = pa;
+	}
+	return 0;
+}
+