vt: add color support to the "underline" and "italic" attributes

Add color support to the "underline" and "italic" attributes as in
OpenBSD/NetBSD-style (vt220) and xterm.

Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Acked-by: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 28 insertions, 6 deletions

diff --git a/drivers/char/vt.c b/drivers/char/vt.c
index 4ef9a286a230..4818327180ac 100644
--- a/drivers/char/vt.c
+++ b/drivers/char/vt.c
@@ -348,10 +348,12 @@ void update_region(struct vc_data *vc, unsigned long start, int count)
 
 /* Structure of attributes is hardware-dependent */
 
-static u8 build_attr(struct vc_data *vc, u8 _color, u8 _intensity, u8 _blink, u8 _underline, u8 _reverse)
+static u8 build_attr(struct vc_data *vc, u8 _color, u8 _intensity, u8 _blink,
+    u8 _underline, u8 _reverse, u8 _italic)
 {
         if (vc->vc_sw->con_build_attr)
-                return vc->vc_sw->con_build_attr(vc, _color, _intensity, _blink, _underline, _reverse);
+                return vc->vc_sw->con_build_attr(vc, _color, _intensity,
+                       _blink, _underline, _reverse, _italic);
 
 #ifndef VT_BUF_VRAM_ONLY
 /*
@@ -368,10 +370,13 @@ static u8 build_attr(struct vc_data *vc, u8 _color, u8 _intensity, u8 _blink, u8
         u8 a = vc->vc_color;
         if (!vc->vc_can_do_color)
                 return _intensity |
+                       (_italic ? 2 : 0) |
                        (_underline ? 4 : 0) |
                        (_reverse ? 8 : 0) |
                        (_blink ? 0x80 : 0);
-        if (_underline)
+        if (_italic)
+                a = (a & 0xF0) | vc->vc_itcolor;
+        else if (_underline)
                 a = (a & 0xf0) | vc->vc_ulcolor;
         else if (_intensity == 0)
                 a = (a & 0xf0) | vc->vc_ulcolor;
@@ -392,8 +397,10 @@ static u8 build_attr(struct vc_data *vc, u8 _color, u8 _intensity, u8 _blink, u8
 
 static void update_attr(struct vc_data *vc)
 {
-        vc->vc_attr = build_attr(vc, vc->vc_color, vc->vc_intensity, vc->vc_blink, vc->vc_underline, vc->vc_reverse ^ vc->vc_decscnm);
-        vc->vc_video_erase_char = (build_attr(vc, vc->vc_color, 1, vc->vc_blink, 0, vc->vc_decscnm) << 8) | ' ';
+        vc->vc_attr = build_attr(vc, vc->vc_color, vc->vc_intensity,
+                      vc->vc_blink, vc->vc_underline,
+                      vc->vc_reverse ^ vc->vc_decscnm, vc->vc_italic);
+        vc->vc_video_erase_char = (build_attr(vc, vc->vc_color, 1, vc->vc_blink, 0, vc->vc_decscnm, 0) << 8) | ' ';
 }
 
 /* Note: inverting the screen twice should revert to the original state */
@@ -1136,6 +1143,7 @@ static void csi_X(struct vc_data *vc, int vpar) /* erase the following vpar posi
 static void default_attr(struct vc_data *vc)
 {
         vc->vc_intensity = 1;
+        vc->vc_italic = 0;
         vc->vc_underline = 0;
         vc->vc_reverse = 0;
         vc->vc_blink = 0;
@@ -1158,6 +1166,9 @@ static void csi_m(struct vc_data *vc)
                         case 2:
                                 vc->vc_intensity = 0;
                                 break;
+                        case 3:
+                                vc->vc_italic = 1;
+                                break;
                         case 4:
                                 vc->vc_underline = 1;
                                 break;
@@ -1198,6 +1209,9 @@ static void csi_m(struct vc_data *vc)
                         case 22:
                                 vc->vc_intensity = 1;
                                 break;
+                        case 23:
+                                vc->vc_italic = 0;
+                                break;
                         case 24:
                                 vc->vc_underline = 0;
                                 break;
@@ -1458,6 +1472,7 @@ static void save_cur(struct vc_data *vc)
         vc->vc_saved_x          = vc->vc_x;
         vc->vc_saved_y          = vc->vc_y;
         vc->vc_s_intensity      = vc->vc_intensity;
+        vc->vc_s_italic         = vc->vc_italic;
         vc->vc_s_underline      = vc->vc_underline;
         vc->vc_s_blink          = vc->vc_blink;
         vc->vc_s_reverse        = vc->vc_reverse;
@@ -1472,6 +1487,7 @@ static void restore_cur(struct vc_data *vc)
 {
         gotoxy(vc, vc->vc_saved_x, vc->vc_saved_y);
         vc->vc_intensity        = vc->vc_s_intensity;
+        vc->vc_italic           = vc->vc_s_italic;
         vc->vc_underline        = vc->vc_s_underline;
         vc->vc_blink            = vc->vc_s_blink;
         vc->vc_reverse          = vc->vc_s_reverse;
@@ -2686,6 +2702,11 @@ static void con_close(struct tty_struct *tty, struct file *filp)
         mutex_unlock(&tty_mutex);
 }
 
+static int default_italic_color    = 2; // green (ASCII)
+static int default_underline_color = 3; // cyan (ASCII)
+module_param_named(italic, default_italic_color, int, S_IRUGO | S_IWUSR);
+module_param_named(underline, default_underline_color, int, S_IRUGO | S_IWUSR);
+
 static void vc_init(struct vc_data *vc, unsigned int rows,
                     unsigned int cols, int do_clear)
 {
@@ -2705,7 +2726,8 @@ static void vc_init(struct vc_data *vc, unsigned int rows,
                 vc->vc_palette[k++] = default_blu[j] ;
         }
         vc->vc_def_color       = 0x07;   /* white */
-        vc->vc_ulcolor          = 0x0f;   /* bold white */
+        vc->vc_ulcolor         = default_underline_color;
+        vc->vc_itcolor         = default_italic_color;
         vc->vc_halfcolor       = 0x08;   /* grey */
         init_waitqueue_head(&vc->paste_wait);
         reset_terminal(vc, do_clear);