Any terminal younger than ~40 years requires lowercase commands, thus they
need to be exempt from uppercasing. And Linux doesn't really support
ancient all-uppercase terminals anyway (no XCASE, etc) even if someone made
the effort to somehow connect them electrically.
This bug is reproducible as of Linux 0.11 and I see it in 0.01 sources
(whose images fail to boot for me, I didn't try very hard). It was less of
a failure then as the shell didn't produce tty codes for normal operation.
Signed-off-by: Adam Borowski <kilob...@angband.pl>
---
drivers/tty/n_tty.c | 58 ++++++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 46 insertions(+), 12 deletions(-)
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index bdf0e6e89991..bbc9f07c19fa 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -87,6 +87,8 @@
# define n_tty_trace(f, args...)
#endif
+enum { ESnormal, ESesc, EScsi, ESsetG };
+
struct n_tty_data {
/* producer-published */
size_t read_head;
@@ -121,6 +123,7 @@ struct n_tty_data {
unsigned int column;
unsigned int canon_column;
size_t echo_tail;
+ unsigned int vt_state;
struct mutex atomic_read_lock;
struct mutex output_lock;
@@ -392,6 +395,40 @@ static inline int is_continuation(unsigned char c, struct
tty_struct *tty)
return I_IUTF8(tty) && is_utf8_continuation(c);
}
+/* process one OLCUC char (possibly partial unicode)
+ *
+ * We need to partially parse ANSI sequences to avoid uppercasing them;
+ * only some commands require lowercase.
+ */
+
+static int do_olcuc_char(unsigned char c, struct tty_struct *tty)
+{
+ struct n_tty_data *ldata = tty->disc_data;
+
+ switch (ldata->vt_state) {
+ case ESesc:
+ ldata->vt_state = (c == '[') ? EScsi :
+ strchr("%()*+-./", c) ? ESsetG : ESnormal;
+ break;
+ case EScsi:
+ if (!strchr("?;0123456789>!c$\" \\", c))
+ ldata->vt_state = ESnormal;
+ break;
+ case ESsetG:
+ ldata->vt_state = ESnormal;
+ break;
+ default:
+ if (c == '\e')
+ ldata->vt_state = ESesc;
+ else if (c >= 'a' && c <= 'z')
+ c -= 32;
+ }
+ if (!iscntrl(c) && !is_continuation(c, tty))
+ ldata->column++;
+ tty_put_char(tty, c);
+ return 1;
+}
+
/**
* do_output_char - output one character
* @c: character (or partial unicode symbol)
@@ -462,12 +499,10 @@ static int do_output_char(unsigned char c, struct
tty_struct *tty, int space)
ldata->column--;
break;
default:
- if (!iscntrl(c)) {
- if (O_OLCUC(tty))
- c = toupper(c);
- if (!is_continuation(c, tty))
- ldata->column++;
- }
+ if (O_OLCUC(tty))
+ return do_olcuc_char(c, tty);
+ if (!iscntrl(c) && !is_continuation(c, tty))
+ ldata->column++;
break;
}
@@ -568,12 +603,10 @@ static ssize_t process_output_block(struct tty_struct
*tty,
ldata->column--;
break;
default:
- if (!iscntrl(c)) {
- if (O_OLCUC(tty))
- goto break_out;
- if (!is_continuation(c, tty))
- ldata->column++;
- }
+ if (O_OLCUC(tty))
+ goto break_out;
+ if (!iscntrl(c) && !is_continuation(c, tty))
+ ldata->column++;
break;
}
}
@@ -1895,6 +1928,7 @@ static int n_tty_open(struct tty_struct *tty)
ldata->num_overrun = 0;
ldata->no_room = 0;
ldata->lnext = 0;
+ ldata->vt_state = ESnormal;
tty->closing = 0;
/* indicate buffer work may resume */
clear_bit(TTY_LDISC_HALTED, &tty->flags);
--
2.11.0
