kernel/linux.git/drivers/tty/vt, branch v3.15.2

vt: detect and ignore OSC codes.

2014-03-01T00:25:47+00:00

These can be used to send commands consisting of an arbitrary string to the terminal, most often used to set a terminal's window title or to redefine the colour palette. Our console doesn't use OSC, unlike everything else, which can lead to junk being displayed if a process sends such a code unconditionally. The rules for termination follow established practice rather than Ecma-48. Ecma-48 requires the string to use only byte values 0x08..0x0D and 0x20..0x7E, terminated with either ESC \ or 0x9C. This would disallow using 8-bit characters, which are reasonable for example in window titles. A widespread idiom is to terminate with 0x07. The behaviour for other control characters differs between terminal emulators, I followed libvte and xterm: * 0x07 and ESC anything terminate * nothing else terminates, all 8-bit values including 0x9C are considered a part of the string Signed-off-by: Adam Borowski Signed-off-by: Greg Kroah-Hartman

vt: drop an useless enum and assignment.

2014-03-01T00:25:47+00:00

Signed-off-by: Adam Borowski Signed-off-by: Greg Kroah-Hartman

vt: Fix secure clear screen

2014-02-13T19:12:00+00:00

\E[3J console code (secure clear screen) needs to update_screen(vc) in order to write-through blanks into off-screen video memory. This has been removed accidentally in 3.6 by: commit 81732c3b2fede049a692e58a7ceabb6d18ffb18c Author: Jean-François Moine Date: Thu Sep 6 19:24:13 2012 +0200 tty vt: Fix line garbage in virtual console on command line edition Signed-off-by: Petr Písař Cc: stable # 3.6 Signed-off-by: Greg Kroah-Hartman

vt: properly ignore xterm-256 colour codes

2013-09-26T22:58:27+00:00

This is not a bug on our side, but a misdesign in ITU T.416, yet with all popular terminals supporting these codes, people consider this to be a bug in Linux. By breaking the design principles behind SGR codes (gracefully ignoring unsupported ones should not require knowing about them), 256 colour ones tend to turn blinking on before invoking an arbitrary unrelated command. This commit doesn't add such support, merely skips such codes without ill effects. Signed-off-by: Adam Borowski Signed-off-by: Greg Kroah-Hartman

vt: break a couple of obsolete SCOish codes.

2013-09-26T22:58:26+00:00

No modern terminal supports them, and SGR 38 conflicts with detecting xterm-256 colours. This also makes SGR 39 consistent with other popular terminals. Neither are used by ncurses' terminfo. Signed-off-by: Adam Borowski Signed-off-by: Greg Kroah-Hartman

vt: make the default color configurable

2013-08-05T07:06:46+00:00

The virtual console has (undocumented) module parameters to set the colors for italic and underlined text, but the default text color was hardcoded for some reason. This made it impossible to change the color for startup messages, or to set the default for new virtual consoles. Add a module parameter for that, and document the entire bunch. Any hacker who thinks that a command prompt on a "black screen with white font" is not supicious enough can now use the kernel parameter vt.color=10 to get a nice, evil green. Signed-off-by: Clemens Ladisch Signed-off-by: Greg Kroah-Hartman

tty: Remove dead code

2013-07-26T23:19:48+00:00

-> The ledptrs[] array is never initialized. -> There is no place where kbd->ledmode is set to LED_SHOW_MEM therefore the if statement does not make much sense. -> Since LED_SHOW_MEM is not used, it can be removed from the header file as well. Signed-off-by: Andreas Platschek Signed-off-by: Greg Kroah-Hartman

tty: Fix unsafe vt paste_selection()

2013-07-23T23:47:10+00:00

Convert the tty_buffer_flush() exclusion mechanism to a public interface - tty_buffer_lock/unlock_exclusive() - and use the interface to safely write the paste selection to the line discipline. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: Convert termios_mutex to termios_rwsem

2013-07-23T23:43:01+00:00

termios is commonly accessed unsafely (especially by N_TTY) because the existing mutex forces exclusive access. Convert existing usage. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

tty: Make ldisc input flow control concurrency-friendly

2013-07-23T23:42:59+00:00

Although line discipline receiving is single-producer/single-consumer, using tty->receive_room to manage flow control creates unnecessary critical regions requiring additional lock use. Instead, introduce the optional .receive_buf2() ldisc method which returns the # of bytes actually received. Serialization is guaranteed by the caller. In turn, the line discipline should schedule the buffer work item whenever space becomes available; ie., when there is room to receive data and receive_room() previously returned 0 (the buffer work item stops processing if receive_buf2() returns 0). Note the 'no room' state need not be atomic despite concurrent use by two threads because only the buffer work thread can set the state and only the read() thread can clear the state. Add n_tty_receive_buf2() as the receive_buf2() method for N_TTY. Provide a public helper function, tty_ldisc_receive_buf(), to use when directly accessing the receive_buf() methods. Line disciplines not using input flow control can continue to set tty->receive_room to a fixed value and only provide the receive_buf() method. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman