[dynui] Add concept of a secret user interface item

For interactive forms, the concept of a secret value becomes
meaningful (e.g. for password fields).

Add a flag to indicate that an item represents a secret value, and
allow this flag to be set via the "--secret" option of the "item"
command.

This flag has no meaning for menu items, but is silently accepted
anyway to keep the code size minimal.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/hci/commands/dynui_cmd.c

@@ -116,6 +116,8 @@ struct item_options {
 	unsigned int key;
 	/** Use as default */
 	int is_default;
+	/** Value is a secret */
+	int is_secret;
 	/** Use as a separator */
 	int is_gap;
 };
@@ -128,6 +130,8 @@ static struct option_descriptor item_opts[] = {
 		      struct item_options, key, parse_key ),
 	OPTION_DESC ( "default", 'd', no_argument,
 		      struct item_options, is_default, parse_flag ),
+	OPTION_DESC ( "secret", 's', no_argument,
+		      struct item_options, is_secret, parse_flag ),
 	OPTION_DESC ( "gap", 'g', no_argument,
 		      struct item_options, is_gap, parse_flag ),
 };
@@ -177,6 +181,8 @@ static int item_exec ( int argc, char **argv ) {
 	/* Add dynamic user interface item */
 	if ( opts.is_default )
 		flags |= DYNUI_DEFAULT;
+	if ( opts.is_secret )
+		flags |= DYNUI_SECRET;
 	item = add_dynui_item ( dynui, name, ( text ? text : "" ), flags,
 				opts.key );
 	if ( ! item ) {

src/include/ipxe/dynui.h

@@ -44,6 +44,9 @@ struct dynamic_item {
 /** Dynamic user interface item is default selection */
 #define DYNUI_DEFAULT 0x0001
 
+/** Dynamic user interface item represents a secret */
+#define DYNUI_SECRET 0x0002
+
 extern struct dynamic_ui * create_dynui ( const char *name, const char *title );
 extern struct dynamic_item * add_dynui_item ( struct dynamic_ui *dynui,
 					      const char *name,