sd-boot: Draw custom edit cursor

Firmware likes to draw the EFI provided cursor in a weird way that
makes it invisible sometimes. This is even more likely to happen
if unusual colors are picked. It also fails to draw attention to the
user by being very small and not blinking.

Additionally, to make it more clear that we are in edit mode, we
now default to inverting the general default color and use that for
our line edit.

Fixes: #19301

2 files changed, 17 insertions, 13 deletions

diff --git a/meson_options.txt b/meson_options.txt
index bcde759044..b122f275da 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -436,7 +436,7 @@ option('efi-color-entry', type : 'string', value : 'lightgray,black',
        description : 'boot loader color for entries')
 option('efi-color-highlight', type : 'string', value : 'black,lightgray',
        description : 'boot loader color for selected entries')
-option('efi-color-edit', type : 'string', value : 'lightgray,black',
+option('efi-color-edit', type : 'string', value : 'black,lightgray',
        description : 'boot loader color for option line edit')
 
 option('bashcompletiondir', type : 'string',
diff --git a/src/boot/efi/boot.c b/src/boot/efi/boot.c
index 549a4814eb..13ba792b18 100644
--- a/src/boot/efi/boot.c
+++ b/src/boot/efi/boot.c
@@ -21,6 +21,8 @@
 #define EFI_OS_INDICATIONS_BOOT_TO_FW_UI 0x0000000000000001ULL
 #endif
 
+#define TEXT_ATTR_SWAP(c) EFI_TEXT_ATTR(((c) & 0b11110000) >> 4, (c) & 0b1111)
+
 /* magic string to find in the binary image */
 static const char _used_ _section_(".sdmagic") magic[] = "#### LoaderInfo: systemd-boot " GIT_VERSION " ####";
 
@@ -116,8 +118,6 @@ static BOOLEAN line_edit(
         len = StrLen(line);
         print = AllocatePool((x_max+1) * sizeof(CHAR16));
 
-        uefi_call_wrapper(ST->ConOut->EnableCursor, 2, ST->ConOut, TRUE);
-
         first = 0;
         cursor = 0;
         clear = 0;
@@ -127,24 +127,29 @@ static BOOLEAN line_edit(
                 EFI_STATUS err;
                 UINT64 key;
                 UINTN j;
+                UINTN cursor_color = TEXT_ATTR_SWAP(COLOR_EDIT);
 
-                j = len - first;
-                if (j >= x_max-1)
-                        j = x_max-1;
+                j = MIN(len - first, x_max);
                 CopyMem(print, line + first, j * sizeof(CHAR16));
-                while (clear > 0 && j < x_max-1) {
+                while (clear > 0 && j < x_max) {
                         clear--;
                         print[j++] = ' ';
                 }
                 print[j] = '\0';
 
-                /* See comment at call site. */
+                /* See comment at edit_line() call site for why we start at 1. */
                 print_at(1, y_pos, COLOR_EDIT, print);
-                uefi_call_wrapper(ST->ConOut->SetCursorPosition, 3, ST->ConOut, cursor + 1, y_pos);
 
-                err = console_key_read(&key, 0);
-                if (EFI_ERROR(err))
-                        continue;
+                if (!print[cursor])
+                        print[cursor] = ' ';
+                print[cursor+1] = '\0';
+                do {
+                        print_at(cursor + 1, y_pos, cursor_color, print + cursor);
+                        cursor_color = TEXT_ATTR_SWAP(cursor_color);
+
+                        err = console_key_read(&key, 750 * 1000);
+                        print_at(cursor + 1, y_pos, COLOR_EDIT, print + cursor);
+                } while (EFI_ERROR(err));
 
                 switch (key) {
                 case KEYPRESS(0, SCAN_ESC, 0):
@@ -330,7 +335,6 @@ static BOOLEAN line_edit(
                 }
         }
 
-        uefi_call_wrapper(ST->ConOut->EnableCursor, 2, ST->ConOut, FALSE);
         return enter;
 }