partx: fix --nr usage

Reported-by: Serge van den Boom <serge+util-linux@vdboom.org>
Signed-off-by: Karel Zak <kzak@redhat.com>

Documentation/releases/v2.28-ReleaseNotes

@@ -41,7 +41,7 @@ The library libsmartcols has been massively improved to print table ranges,
 multi-line cells, table titles and to support continuous printing.
 
 The package build system and code have been improved to be more portable to
-non-Linux systems (BSD, XOs).
+non-Linux systems (BSD, OSX).
 
 The package does not provide fallback solutions for openat-family functions
 anymore.

disk-utils/partx.8

@@ -68,7 +68,7 @@ Do not use it in newly written scripts.
 Specify the range of partitions.  For backward compatibility also the
 format \fIM\fB\-\fIN\fR is supported.
 The range may contain negative numbers, for example
-.B \-\-nr :\-1
+.B \-\-nr -\1:\-1
 means the last partition, and
 .B \-\-nr \-2:\-1
 means the last two partitions.  Supported range specifications are:

disk-utils/partx.c

@@ -267,6 +267,30 @@ dflt:
 	return SLICES_MAX;
 }
 
+static int recount_range_by_pt(blkid_partlist ls, int *lower, int *upper)
+{
+	int n = 0, i, nparts = blkid_partlist_numof_partitions(ls);
+
+	for (i = 0; i < nparts; i++) {
+		blkid_partition par = blkid_partlist_get_partition(ls, i);
+		int partno = blkid_partition_get_partno(par);
+		n = max(partno, n);
+	}
+
+	if (*lower < 0)
+		*lower = n + *lower + 1;
+	if (*upper < 0)
+		*upper = n + *upper + 1;
+
+	if (*lower > *upper && *upper != 0) {
+		warnx(_("specified range <%d:%d> does not make sense"), *lower, *upper);
+		return -EINVAL;
+	}
+	if (verbose)
+		printf(_("range recount: max partno=%d, lower=%d, upper=%d\n"), n, *lower, *upper);
+	return 0;
+}
+
 static void del_parts_warnx(const char *device, int first, int last)
 {
 	if (first == last)
@@ -284,6 +308,7 @@ static int del_parts(int fd, const char *device, dev_t devno,
 	assert(fd >= 0);
 	assert(device);
 
+	/* recount range by information in /sys */
 	if (!lower)
 		lower = 1;
 	if (!upper || lower < 0 || upper < 0) {
@@ -343,12 +368,16 @@ static void add_parts_warnx(const char *device, int first, int last)
 static int add_parts(int fd, const char *device,
 		     blkid_partlist ls, int lower, int upper)
 {
-	int i, nparts, rc = 0, errfirst = 0, errlast = 0;
+	int i, nparts, rc, errfirst = 0, errlast = 0;
 
 	assert(fd >= 0);
 	assert(device);
 	assert(ls);
 
+	rc = recount_range_by_pt(ls, &lower, &upper);
+	if (rc)
+		return rc;
+
 	nparts = blkid_partlist_numof_partitions(ls);
 
 	for (i = 0; i < nparts; i++) {
@@ -430,6 +459,8 @@ static int upd_parts(int fd, const char *device, dev_t devno,
 	assert(device);
 	assert(ls);
 
+	/* recount range by information in /sys, if on disk number of
+	 * partitions is greater than in /sys the use on-disk limit */
 	nparts = blkid_partlist_numof_partitions(ls);
 	if (!lower)
 		lower = 1;
@@ -505,10 +536,14 @@ static int upd_parts(int fd, const char *device, dev_t devno,
 
 static int list_parts(blkid_partlist ls, int lower, int upper)
 {
-	int i, nparts;
+	int i, nparts, rc;
 
 	assert(ls);
 
+	rc = recount_range_by_pt(ls, &lower, &upper);
+	if (rc)
+		return rc;
+
 	nparts = blkid_partlist_numof_partitions(ls);
 
 	for (i = 0; i < nparts; i++) {
@@ -645,6 +680,10 @@ static int show_parts(blkid_partlist ls, int scols_flags, int lower, int upper)
 		}
 	}
 
+	rc = recount_range_by_pt(ls, &lower, &upper);
+	if (rc)
+		goto done;
+
 	for (i = 0; i < nparts; i++) {
 		blkid_partition par = blkid_partlist_get_partition(ls, i);
 		int n = blkid_partition_get_partno(par);
@@ -880,6 +919,9 @@ int main(int argc, char **argv)
 		} else {
 			device = argv[optind];
 			wholedisk = xstrdup(argv[optind + 1]);
+
+			if (device && wholedisk && !startswith(device, wholedisk))
+				errx(EXIT_FAILURE, _("partition and disk name do not match"));
 		}
 	} else if (optind == argc - 1) {
 		/* passed only one arg (ie: /dev/sda3 or /dev/sda) */
@@ -964,18 +1006,6 @@ int main(int argc, char **argv)
 			ls = get_partlist(pr, wholedisk, type);
 
 		if (ls) {
-			int n = blkid_partlist_numof_partitions(ls);
-
-			if (lower < 0)
-				lower = n + lower + 1;
-			if (upper < 0)
-				upper = n + upper + 1;
-			if (lower > upper) {
-				warnx(_("specified range <%d:%d> "
-					"does not make sense"), lower, upper);
-				rc = -1, what = ACT_NONE;
-			}
-
 			switch (what) {
 			case ACT_SHOW:
 				rc = show_parts(ls, scols_flags, lower, upper);
@@ -988,6 +1018,7 @@ int main(int argc, char **argv)
 				break;
 			case ACT_UPD:
 				rc = upd_parts(fd, wholedisk, disk_devno, ls, lower, upper);
+				break;
 			case ACT_NONE:
 				break;
 			default:

lib/strutils.c

@@ -734,7 +734,7 @@ int parse_range(const char *str, int *lower, int *upper, int def)
 			return -1;
 
 		if (*end == ':' && !*(end + 1))		/* <M:> */
-			*upper = 0;
+			*upper = def;
 		else if (*end == '-' || *end == ':') {	/* <M:N> <M-N> */
 			str = end + 1;
 			end = NULL;