lsblk: allow to specify tree column

* document --tree (was missing in the man page)
* add optional argument to --tree to specify tree

For example:

$ lsblk -o KNAME,SIZE,MOUNTPOINT --tree=KNAME /dev/dm-0
KNAME      SIZE MOUNTPOINT
dm-0     232.9G
└─dm-1   232.9G
  └─dm-2 232.9G

Signed-off-by: Karel Zak <kzak@redhat.com>

3 files changed, 26 insertions, 10 deletions

diff --git a/misc-utils/lsblk.8 b/misc-utils/lsblk.8
index 2787569fe..07cd7a16f 100644
--- a/misc-utils/lsblk.8
+++ b/misc-utils/lsblk.8
@@ -30,6 +30,8 @@ is subject to change.  So whenever possible, you should avoid using default
 outputs in your scripts.  Always explicitly define expected columns by using
 .B \-\-output
 .I columns-list
+and
+.B \-\-list
 in environments where a stable output is required.
 .PP
 Note that
@@ -135,6 +137,10 @@ Output info about SCSI devices only.  All partitions, slaves and holder devices
 Print dependencies in inverse order. If the \fB\-\-list\fR output is requested then
 the lines are still ordered by dependencies.
 .TP
+.BR \-T , " \-\-tree" [ =\fIcolumn ]
+Force tree-like output format.  If \fIcolumn\fP is specified, then a tree is printed in the column.
+The default is NAME column.
+.TP
 .BR \-t , " \-\-topology"
 Output info about block-device topology.
 This option is equivalent to
diff --git a/misc-utils/lsblk.c b/misc-utils/lsblk.c
index ffa1f82bf..454f067c8 100644
--- a/misc-utils/lsblk.c
+++ b/misc-utils/lsblk.c
@@ -146,7 +146,7 @@ struct colinfo {
 
 /* columns descriptions */
 static struct colinfo infos[] = {
-	[COL_NAME]   = { "NAME",    0.25, SCOLS_FL_TREE | SCOLS_FL_NOEXTREMES, N_("device name") },
+	[COL_NAME]   = { "NAME",    0.25, SCOLS_FL_NOEXTREMES, N_("device name") },
 	[COL_KNAME]  = { "KNAME",   0.3, 0, N_("internal kernel device name") },
 	[COL_PKNAME] = { "PKNAME",  0.3, 0, N_("internal parent kernel device name") },
 	[COL_PATH]   = { "PATH",    0.3,  0, N_("path to the device node") },
@@ -1725,7 +1725,7 @@ static void __attribute__((__noreturn__)) usage(void)
 	fputs(_(" -O, --output-all     output all columns\n"), out);
 	fputs(_(" -P, --pairs          use key=\"value\" output format\n"), out);
 	fputs(_(" -S, --scsi           output info about SCSI devices\n"), out);
-	fputs(_(" -T, --tree           use tree format output\n"), out);
+	fputs(_(" -T, --tree[=<column>] use tree format output\n"), out);
 	fputs(_(" -a, --all            print all devices\n"), out);
 	fputs(_(" -b, --bytes          print SIZE in bytes rather than in human readable format\n"), out);
 	fputs(_(" -d, --nodeps         don't print slaves or holders\n"), out);
@@ -1769,13 +1769,14 @@ int main(int argc, char *argv[])
 	struct lsblk _ls = {
 		.sort_id = -1,
 		.dedup_id = -1,
-		.flags = LSBLK_TREE
+		.flags = LSBLK_TREE,
+		.tree_id = COL_NAME
 	};
 	struct lsblk_devtree *tr = NULL;
 	int c, status = EXIT_FAILURE;
 	char *outarg = NULL;
 	size_t i;
-	int force_tree = 0;
+	int force_tree = 0, has_tree_col = 0;
 
 	enum {
 		OPT_SYSROOT = CHAR_MAX + 1
@@ -1808,7 +1809,7 @@ int main(int argc, char *argv[])
 		{ "scsi",       no_argument,       NULL, 'S' },
 		{ "sort",	required_argument, NULL, 'x' },
 		{ "sysroot",    required_argument, NULL, OPT_SYSROOT },
-		{ "tree",       no_argument,       NULL, 'T' },
+		{ "tree",       optional_argument, NULL, 'T' },
 		{ "version",    no_argument,       NULL, 'V' },
 		{ NULL, 0, NULL, 0 },
 	};
@@ -1836,7 +1837,7 @@ int main(int argc, char *argv[])
 	lsblk_init_debug();
 
 	while((c = getopt_long(argc, argv,
-			       "abdDzE:e:fhJlnMmo:OpPiI:rstVSTx:", longopts, NULL)) != -1) {
+			       "abdDzE:e:fhJlnMmo:OpPiI:rstVST:x:", longopts, NULL)) != -1) {
 
 		err_exclusive_options(c, longopts, excl, excl_st);
 
@@ -1948,8 +1949,9 @@ int main(int argc, char *argv[])
 			break;
 		case 'T':
 			force_tree = 1;
+			if (optarg)
+				lsblk->tree_id = column_name_to_id(optarg, strlen(optarg));
 			break;
-
 		case OPT_SYSROOT:
 			lsblk->sysroot = optarg;
 			break;
@@ -2039,8 +2041,14 @@ int main(int argc, char *argv[])
 		struct libscols_column *cl;
 		int id = get_column_id(i), fl = ci->flags;
 
-		if (!(lsblk->flags & LSBLK_TREE) && id == COL_NAME)
-			fl &= ~SCOLS_FL_TREE;
+		if ((lsblk->flags & LSBLK_TREE)
+		    && has_tree_col == 0
+		    && id == lsblk->tree_id) {
+			fl |= SCOLS_FL_TREE;
+			fl &= ~SCOLS_FL_RIGHT;
+			has_tree_col = 1;
+		}
+
 		if (lsblk->sort_hidden && lsblk->sort_id == id)
 			fl |= SCOLS_FL_HIDDEN;
 		if (lsblk->dedup_hidden && lsblk->dedup_id == id)
diff --git a/misc-utils/lsblk.h b/misc-utils/lsblk.h
index e15c5b42a..da2edc09b 100644
--- a/misc-utils/lsblk.h
+++ b/misc-utils/lsblk.h
@@ -35,7 +35,9 @@ struct lsblk {
 	struct libscols_table *table;	/* output table */
 
 	struct libscols_column *sort_col;/* sort output by this column */
-	int sort_id;
+
+	int sort_id;			/* id of the sort column */
+	int tree_id;			/* od of column used for tree */
 
 	int dedup_id;