This adds a minimalistic braille screen reader support. This is meant to
be used by blind people e.g. on boot failures or when / cannot be mounted
etc and thus the userland screen readers can not work.
[akpm@linux-foundation.org: fix exports]
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Jiri Kosina <jikos@jikos.cz>
Cc: Dmitry Torokhov <dtor@mail.ru>
Acked-by: Alan Cox <alan@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Historically tty->pgrp and friends were pid_t and the code "knew" they were
safe. The change to pid structs opened up a few races and the removal of the
BKL in places made them quite hittable. We put tty->pgrp under the ctrl_lock
for the tty.
Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Push the BKL down into the line disciplines
- Switch the tty layer to unlocked_ioctl
- Introduce a new ctrl_lock spin lock for the control bits
- Eliminate much of the lock_kernel use in n_tty
- Prepare to (but don't yet) call the drivers with the lock dropped
on the paths that historically held the lock
BKL now primarily protects open/close/ldisc change in the tty layer
[jirislaby@gmail.com: a couple of fixes]
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A command that causes a line feed while a background color is active,
such as
perl -e 'print "x" x 60, "\e[44m", "x" x 40, "\e[0m\n"'
and
perl -e 'print "x" x 40, "\e[44m\n", "x" x 40, "\e[0m\n"'
causes the line that was started as a result of the line feed to be completely
filled with the currently active background color instead of the default
color.
When scrolling, part of the current screen is memcpy'd/memmove'd to the new
region, and the new line(s) that will appear as a result are cleared using
memset. However, the lines are cleared with vc->vc_video_erase_char, causing
them to be colored with the currently active background color. This is
different from X11 terminal emulators which always paint the new lines with
the default background color (e.g. `xterm -bg black`).
The clear operation (\e[1J and \e[2J) also use vc_video_erase_char, so a new
vc->vc_scrl_erase_char is introduced with contains the erase character used
for scrolling, which is built from vc->vc_def_color instead of vc->vc_color.
Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some accessibility modules need to be able to catch the output on the
console before the VT interpretation, and possibly swallow it.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
VT notifier callbacks need to be aware of console switches. This is already
partially done from console_callback(), but at that time fg_console, cursor
positions, etc. are not yet updated and hence screen readers fetch the old
values.
This adds an update notify after all of the values are updated in
redraw_screen(vc, 1).
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
vt is missing a memory barrier to close the critical section. Use a real
spinlock for this.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some external modules like Speakup need to monitor console output.
This adds a VT notifier that such modules can use to get console output events:
allocation, deallocation, writes, other updates (cursor position, switch, etc.)
[akpm@linux-foundation.org: fix headers_check]
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since default_utf8 is already a sysfs attribute, having an extra
CONFIG_VT_UNICODE compile-time option is redundant, since sysfs attributes can
be set at boot and run time.
Also let Linux VCs default to UTF-8 (as per the discussion at
http://lkml.org/lkml/2007/9/6/99).
Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Cc: Bill Nottingham <notting@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As of now, the kernel defaults to non-unicode and XLATE for the keyboard.
We've been changing this in Fedora, but that requires patching the defaults
in the kernel.
The attached introduces CONFIG_VT_UNICODE, which sets the console in
unicode mode by default on boot, including both the virtual terminal and
the keyboard driver.
Signed-off-by: Bill Nottingham <notting@redhat.com>
Cc: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Various console drivers are able to resize the screen via the con_resize()
hook. This hook is also visible in userspace via the TIOCWINSZ, VT_RESIZE and
VT_RESIZEX ioctl's. One particular utility, SVGATextMode, expects that
con_resize() of the VGA console will always return success even if the
resulting screen is not compatible with the hardware. However, this
particular behavior of the VGA console, as reported in Kernel Bugzilla Bug
7513, can cause undefined behavior if the user starts with a console size
larger than 80x25.
To work around this problem, add an extra parameter to con_resize(). This
parameter is ignored by drivers except for vgacon. If this parameter is
non-zero, then the resize request came from a VT_RESIZE or VT_RESIZEX ioctl
and vgacon will always return success. If this parameter is zero, vgacon will
return -EINVAL if the requested size is not compatible with the hardware. The
latter is the more correct behavior.
With this change, SVGATextMode should still work correctly while in-kernel and
stty resize calls can expect correct behavior from vgacon.
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
VGA console driver can misunderstand the current mode(Text/Graphic) under
"disable console blanking" setting. When "disable console blank" is set
(blankinterval=0), "do_unblank_screen()" function returns without changing
"blank_state", and when "blank_state" is "blank_off", "do_blank_screen()
function returns without invoking sw->con_blank() function. That's why VGA
console driver can misunderstand the current mode.
Signed-off-by: Nobuhiro Tachino <ntachino@redhat.com>
Signed-off-by: Taku Izumi <izumi2005@soft.fujitsu.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: "Luck, Tony" <tony.luck@intel.com>
Acked-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allow fbcon to select the primary display adapter using the
fb_is_primary_device() arch-specific helper. If a a primary adapter is
detected, fbcon will unbind the old adapter from the VT layer, then rebind
using the new adapter. This requires that bind_/unbind_con_driver() be made
public.
Because this feature may produce unexpected behavior (from the user's POV),
this must be explicitly enabled in Kconfig.
[akpm@linux-foundation.org: export unbind_con_driver]
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Recently my console UTF-8 patch went mainline. Here is an additional patch
that fixes two nasty issues and improves a third one, namely:
1. My patch changed the behavior if a glyph is not found in the Unicode
mapping table. Previously for Unicode values less than 256 or 512 the
kernel tried to display the glyph from that position of the glyph table,
which could lead to a different accented letter being displayed. I
removed this fallback possibility and changed it to display the
replacement symbol.
As Behdad pointed out, some fonts (e.g. sun12x22 from the kbd package)
lack Unicode mapping information, hence all you get is lots of question
marks. Though theoretically it's actually a user-space bug (the font
should be fixed), Behdad and I both believe that it'd be good to work
around in the kernel by re-introducing the fallback solution for ASCII
characters only. This sounds a quite reasonable decision, since all fonts
ship the ASCII characters in the first 128 positions. This way users
won't be surprised by lots of question marks just because s/he issued a
not-so-perfectly parameterized setfont command. As this fallback is only
re-introduced for code points below 128, you still won't see an accented
letter replaced by another, but at least you'll always get the English
letters right.
2. My patch introduced "question mark with inverted color attributes" as a
last resort fallback glyph. Though it perfectly works on VGA console, on
framebuffer you may end up with question marks that are highlighed but
shouldn't be, and normal characters that are accidentally highlighed.
This is caused by missing FLUSHes when changing the color attribute.
3. I've updated the table of double-width character based on Markus's
updated version. Only ten new code poings (one interval) is added.
Signed-off-by: Egmont Koblinger <egmont@uhulinux.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The virtual console driver uses a semaphore as mutex. Use the mutex API
instead of the (binary) semaphore.
Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Create a variable, default_utf8, that defines the system-wide default UTF-8
setting. This variable can be altered via sysfs. If the variable is properly
set, this should mimimize breakage of UTF-8 encoded consoles when doing a
reset or echo -e '\033c' and of newly opened/allocated consoles.
This is based from patches by Jan Engelhardt and Paul LeoNerd Evans.
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Cc: Jan Engelhardt <jengelh@linux01.gwdg.de>
Cc: Paul LeoNerd Evans <leonerd@leonerd.org.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
Allow for the palette to be exposed and changed via sysfs. A call to
/usr/bin/reset will slurp the new definitions in for the current console.
Already posted at http://lkml.org/lkml/2006/1/15/149
Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The UTF-8 part of the vt driver suffers from the following issues which are
addressed in my patch:
1) If there's no glyph found for a particular valid UTF-8 character, we try
to display U+FFFD. However if this one is not found either, here's what
the current kernel does:
- First, if the Unicode value is less than the number of glyphs, use the
glyph directly from that position of the glyph table. While it may be a
good idea in the 8-bit world, it has absolutely no sense with Unicode
in mind. For example, if a Latin-2 font is loaded and an application
prints U+00FB ("u with circumflex", not present in Latin-2) then as a
fallback solution the glyph from the 0xFB position of the Latin-2
fontset (which is an "u with double accent" - a different character) is
displayed.
- Second, if this fallback fails too, a simple ASCII question mark is
printed, which is visually undistinguishable from a real question mark.
I changed the code to skip the first step (except if in non-UTF-8 mode),
and changed the second step to print the question mark with inverse color
attributes, so it is visually clear that it's not a real question mark,
and resembles more to the common glyph of U+FFFD.
2) The UTF-8 decoder is buggy in many ways:
- Lone continuation bytes (section 3.1 of Markus Kuhn's UTF-8 stress
test) are not caught, they are displayed as some "random" (taken
directly form the font table, see above) glyphs instead the replacement
character.
- Incomplete sequences (sections 3.2 and 3.3 of the stress test) emit no
replacement character, but rather cause the subsequent valid character
to be displayed more times(!).
- The decoder is not safe: overlong sequences are not caught currently,
they are displayed as if these were valid representations. This may
even have security impacts.
- The decoder does not handle D800..DFFF and FFFE..FFFF specially, it
just emits these code points and lets it be looked up in the glyph
table. Since these are invalid code points, I replace them by U+FFFD
and hence give no chance for them to be looked up in the glyph table.
(Assuming no font ships glyphs for these code points, this change is
not visible to the users since the glyph shown will be the same.)
With my fixes to the decoder it now behaves exactly as Markus Kuhn's
stress test recommends.
3) It has no concept of double-width (CJK) characters. It's way beyond the
scope of my patch to try to display them, but at least I think it's
important for the cursor to jump two positions when printing such
characters, since this is what applications (such as text editors)
expect. Currently the cursor only jumps one position, and hence
applications suffer from displaying and refreshing problems, and editing
some English letters that are preceded by some CJK characters in the same
line is a nightmare. With my patch an additional space is inserted after
the CJK character has been printed (which usually means a replacement
symbol of course). (If U+FFFD isn't availble and hence an inverse
question mark is displayed in the first cell, I keep the inverted state
for the space in the 2nd column so it's quite easy to see that they are
tied together.)
4) There is a small built-in table of zero-width spaces that are not to be
printed but silently skipped. U+200A is included there, but it's not a
zero-width character, so I remove it from there.
Signed-off-by: Egmont Koblinger <egmont@uhulinux.hu>
Cc: Jan Engelhardt <jengelh@linux01.gwdg.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the console is in VT_AUTO+KD_GRAPHICS mode, switching to the
SUSPEND_CONSOLE fails, resulting in vt_waitactive() waiting indefinitely or
until the task is interrupted. This patch tests if a console switch can
occur in set_console() and returns early if a console switch is not
possible.
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Andrew Johnson <ajohnson@intrinsyc.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Somewhere in the rewrite of the work queues my cleanup of SAK handling
got broken. Maybe I didn't retest it properly or possibly the API
was changing so fast I missed something. Regardless currently
triggering a SAK now generates an ugly BUG_ON and kills the kernel.
Thanks to Alexey Dobriyan <adobriyan@openvz.org> for spotting this.
This modifies the use of SAK_work to initialize it when the data
structure it resides in is initialized, and to simply call
schedule_work when we need to generate a SAK. I update both
data structures that have a SAK_work member for consistency.
All of the old PREPARE_WORK calls that are now gone.
If we call schedule_work again before it has processed it
has generated the first SAK it will simply ignore the duplicate
schedule_work request.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Of kernel subsystems that work with pids the tty layer is probably the largest
consumer. But it has the nice virtue that the assiation with a session only
lasts until the session leader exits. Which means that no reference counting
is required. So using struct pid winds up being a simple optimization to
avoid hash table lookups.
In the long term the use of pid_nr also ensures that when we have multiple pid
spaces mixed everything will work correctly.
Signed-off-by: Eric W. Biederman <eric@maxwell.lnxi.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Use timer macros to set function and data members and to modify
expiration time.
- Use DEFINE_TIMER for global timers and do not init them at run-time in
these cases.
- del_timer_sync is common in most cases -- we want to wait for timer
function if it's still running.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Dave Airlie <airlied@linux.ie>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Paul Fulghum <paulkf@microgate.com>
Cc: Kylene Jo Hall <kjhall@us.ibm.com>
Cc: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Dmitry Torokhov <dtor@mail.ru> (Input bits)
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add proper prototypes for two functions in drivers/char/vc_screen.c
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Run this:
#!/bin/sh
for f in $(grep -Erl "\([^\)]*\) *k[cmz]alloc" *) ; do
echo "De-casting $f..."
perl -pi -e "s/ ?= ?\([^\)]*\) *(k[cmz]alloc) *\(/ = \1\(/" $f
done
And then go through and reinstate those cases where code is casting pointers
to non-pointers.
And then drop a few hunks which conflicted with outstanding work.
Cc: Russell King <rmk@arm.linux.org.uk>, Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Steven French <sfrench@us.ibm.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Jaroslav Kysela <perex@suse.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Conflicts:
drivers/infiniband/core/iwcm.c
drivers/net/chelsio/cxgb2.c
drivers/net/wireless/bcm43xx/bcm43xx_main.c
drivers/net/wireless/prism54/islpci_eth.c
drivers/usb/core/hub.h
drivers/usb/input/hid-core.c
net/core/netpoll.c
Fix up merge failures with Linus's head and fix new compilation failures.
Signed-Off-By: David Howells <dhowells@redhat.com>
Converts from using struct "class_device" to "struct device" making
everything show up properly in /sys/devices/ with symlinks from the
/sys/class directory.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Pass the work_struct pointer to the work function rather than context data.
The work function can use container_of() to work out the data.
For the cases where the container of the work_struct may go away the moment the
pending bit is cleared, it is made possible to defer the release of the
structure by deferring the clearing of the pending bit.
To make this work, an extra flag is introduced into the management side of the
work_struct. This governs auto-release of the structure upon execution.
Ordinarily, the work queue executor would release the work_struct for further
scheduling or deallocation by clearing the pending bit prior to jumping to the
work function. This means that, unless the driver makes some guarantee itself
that the work_struct won't go away, the work function may not access anything
else in the work_struct or its container lest they be deallocated.. This is a
problem if the auxiliary data is taken away (as done by the last patch).
However, if the pending bit is *not* cleared before jumping to the work
function, then the work function *may* access the work_struct and its container
with no problems. But then the work function must itself release the
work_struct by calling work_release().
In most cases, automatic release is fine, so this is the default. Special
initiators exist for the non-auto-release case (ending in _NAR).
Signed-Off-By: David Howells <dhowells@redhat.com>
This patch adds proper prototypes to header files for three console init
functions used on drivers/char/vt.c
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Check the return value of device_create_file(). If return is 'fail', remove
attributes by calling device_remove_file().
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
As part of an SMP cleanliness pass over UML, I consted a bunch of
structures in order to not have to document their locking. One of these
structures was a struct tty_operations. In order to const it in UML
without introducing compiler complaints, the declaration of
tty_set_operations needs to be changed, and then all of its callers need to
be fixed.
This patch declares all struct tty_operations in the tree as const. In all
cases, they are static and used only as input to tty_set_operations. As an
extra check, I ran an i386 allyesconfig build which produced no extra
warnings.
53 drivers are affected. I checked the history of a bunch of them, and in
most cases, there have been only a handful of maintenance changes in the
last six months. serial_core.c was the busiest one that I looked at.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I took a good hard look at the locking and it appears the locking on vt_pid
is the console semaphore. Every modified path is called under the console
semaphore except reset_vc when it is called from fn_SAK or do_SAK both of
which appear to be in interrupt context. In addition I need to be careful
because in the presence of an oops the console_sem may be arbitrarily
dropped.
Which leads me to conclude the current locking is inadequate for my needs.
Given the weird cases we could hit because of oops printing instead of
introducing an extra spin lock to protect the data and keep the pid to
signal and the signal to send in sync, I have opted to use xchg on just the
struct pid * pointer instead.
Due to console_sem we will stay in sync between vt_pid and vt_mode except
for a small window during a SAK, or oops handling. SAK handling should
kill any user space process that care, and oops handling we are broken
anyway. Besides the worst that can happen is that I try to send the wrong
signal.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Memory leaks can happen in the vc_resize() function in drivers/char/vt.c
because of the vc->vc_screenbuf variable overriding in vc_allocate(). The
kmemleak reported trace is as follows:
<__kmalloc>
<vc_resize>
<fbcon_init>
<visual_init>
<vc_allocate>
<con_open>
<tty_open>
<chrdev_open>
This patch no longer allocates a screen buffer in vc_allocate() if it was
already allocated by vc_resize().
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The current kernel serializes console resizes but does not serialize the
resize against the tty structure updates. This means that while two
parallel resizes cannot mess up the console you can get incorrect results
reported.
Secondly while doing this I added vc_lock_resize() to lock and resize the
console. This leaves all knowledge of the console_sem in the vt/console
driver and kicks it out of the tty layer, which is good
Thirdly while doing this I decided I couldn't stand "disallocate" any
longer so I switched it to "deallocate".
Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix utf-8 mode so alternate charset modes always work according to control
sequences interpreted in do_con_trol function preserving backward US-ASCII
and VT100 semigraphics compatibility.
Malformed utf-8 sequences are represented as sequences of replacement
glyphs,original codes or '?' as a last resort.
unicode-xterm, gnome-terminal, kconsole and other terminal emulators in
utf-8 mode respect acsc, enacs, rmacs sequences. Also I found that some
important system programs (from Debian distro) uses acsc in utf-8 mode -
dselect, aptitude, w3m for example.
Signed-off-by: Adam Tlalka <atlka@pg.gda.pl>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Jon Smirl noted a couple of tty driver functions now are quite misleadingly
named with the death of devfs. A quick grep found another case in the lp
driver.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When a VT is newly allocated, the module reference count of the backend
will be incremented. This should be balanced by a module_put() when this
VT is deallocated.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
To enable this feature, CONFIG_VT_HW_CONSOLE_BINDING must be set to 'y'. This
feature will default to 'n' to minimize users accidentally corrupting their
virtual terminals.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add sysfs control to the VT layer. A new sysfs class, 'vtconsole', and class
devices 'vtcon[n]' are added. Each class device file has the following
attributes:
/sys/class/vtconsole/vtcon[n]/name - read-only attribute showing the
name of the current backend
/sys/class/vtconsole/vtcon[n]/bind - read/write attribute
where: 0 - backend is unbound/unbind backend from the VT layer
1 - backend is bound/bind backend to the VT layer
In addition, if any of the consoles are in KD_GRAPHICS mode, binding and
unbinding will not succeed. KD_GRAPHICS mode usually indicates that the
underlying console hardware is used for other purposes other than displaying
text (ie X). This feature should prevent binding/unbinding from interfering
with a graphics application using the VT.
[akpm@osdl.org: warning fixes]
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The framebuffer console is now able to dynamically bind and unbind from the VT
console layer. Due to the way the VT console layer works, the drivers
themselves decide when to bind or unbind. However, it was decided that
binding must be controlled, not by the drivers themselves, but by the VT
console layer. With this, dynamic binding is possible for all VT console
drivers, not just fbcon.
Thus, the VT console layer will impose the following to all VT console
drivers:
- all registered VT console drivers will be entered in a private list
- drivers can register themselves to the VT console layer, but they cannot
decide when to bind or unbind. (Exception: To maintain backwards
compatibility, take_over_console() will automatically bind the driver after
registration.)
- drivers can remove themselves from the list by unregistering from the VT
console layer. A prerequisite for unregistration is that the driver must not
be bound.
The following functions are new in the vt.c:
register_con_driver() - public function, this function adds the VT console
driver to an internal list maintained by the VT console
bind_con_driver() - private function, it binds the driver to the console
take_over_console() is changed to call register_con_driver() followed by a
bind_con_driver(). This is the only time drivers can decide when to bind to
the VT layer. This is to maintain backwards compatibility.
unbind_con_driver() - private function, it unbinds the driver from its
console. The vacated consoles will be taken over by the default boot console
driver.
unregister_con_driver() - public function, removes the driver from the
internal list maintained by the VT console. It will only succeed if the
driver is currently unbound.
con_is_bound() checks if the driver is currently bound or not
give_up_console() is just a wrapper to unregister_con_driver().
There are also 3 additional functions meant to be called only by the tty layer
for sysfs control:
vt_bind() - calls bind_con_driver()
vt_unbind() - calls unbind_con_driver()
vt_show_drivers() - shows the list of registered drivers
Most VT console drivers will continue to work as is, but might have problems
when unbinding or binding which should be fixable with minimal changes.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
To allow for detaching fbcon, it must be able to give up the console.
However, the function give_up_console() is plain broken. It just sets the
entries in the console driver map to NULL, it leaves the vt layer without a
console driver, and does not decrement the module reference count. Calling
give_up_console() is guaranteed to hang the machine..
To fix this problem, ensure that the virtual consoles are not left dangling
without a driver. All systems have a default boot driver (either vgacon or
dummycon) which is never unloaded. For those vt's that lost their driver, the
default boot driver is reassigned back to them.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
