Some time ago I started working on a library called libteken, which is
terminal emulator. It does not buffer any screen contents, but only
keeps terminal state, such as cursor position, attributes, etc. It
should implement all escape sequences that are implemented by the
cons25 terminal emulator, but also a fair amount of sequences that are
present in VT100 and xterm.
A lot of random notes, which could be of interest to users/developers:
- Even though I'm leaving the terminal type set to `cons25', users can
do experiments with placing `xterm-color' in /etc/ttys. Because we
only implement a subset of features of xterm, this may cause
artifacts. We should consider extending libteken, because in my
opinion xterm is the way to go. Some missing features:
- Keypad application mode (DECKPAM)
- Character sets (SCS)
- libteken is filled with a fair amount of assertions, but unfortunately
we cannot go into the debugger anymore if we fail them. I've done
development of this library almost entirely in userspace. In
sys/dev/syscons/teken there are two applications that can be helpful
when debugging the code:
- teken_demo: a terminal emulator that can be started from a regular
xterm that emulates a terminal using libteken. This application can
be very useful to debug any rendering issues.
- teken_stress: a stress testing application that emulates random
terminal output. libteken has literally survived multiple terabytes
of random input.
- libteken also includes support for UTF-8, but unfortunately our input
layer and font renderer don't support this. If users want to
experiment with UTF-8 support, they can enable `TEKEN_UTF8' in
teken.h. If you recompile your kernel or the teken_demo application,
you can hold some nice experiments.
- I've left PC98 the way it is right now. The PC98 platform has a custom
syscons renderer, which supports some form of localised input. Maybe
we should port PC98 to libteken by the time syscons supports UTF-8?
- I've removed the `dumb' terminal emulator. It has been broken for
years. It hasn't survived the `struct proc' -> `struct thread'
conversion.
- To prevent confusion among people that want to hack on libteken:
unlike syscons, the state machines that parse the escape sequences are
machine generated. This means that if you want to add new escape
sequences, you have to add an entry to the `sequences' file. This will
cause new entries to be added to `teken_state.h'.
- Any rendering artifacts that didn't occur prior to this commit are by
accident. They should be reported to me, so I can fix them.
Discussed on: current@, hackers@
Discussed with: philip (at 25C3)
The last half year I've been working on a replacement TTY layer for the
FreeBSD kernel. The new TTY layer was designed to improve the following:
- Improved driver model:
The old TTY layer has a driver model that is not abstract enough to
make it friendly to use. A good example is the output path, where the
device drivers directly access the output buffers. This means that an
in-kernel PPP implementation must always convert network buffers into
TTY buffers.
If a PPP implementation would be built on top of the new TTY layer
(still needs a hooks layer, though), it would allow the PPP
implementation to directly hand the data to the TTY driver.
- Improved hotplugging:
With the old TTY layer, it isn't entirely safe to destroy TTY's from
the system. This implementation has a two-step destructing design,
where the driver first abandons the TTY. After all threads have left
the TTY, the TTY layer calls a routine in the driver, which can be
used to free resources (unit numbers, etc).
The pts(4) driver also implements this feature, which means
posix_openpt() will now return PTY's that are created on the fly.
- Improved performance:
One of the major improvements is the per-TTY mutex, which is expected
to improve scalability when compared to the old Giant locking.
Another change is the unbuffered copying to userspace, which is both
used on TTY device nodes and PTY masters.
Upgrading should be quite straightforward. Unlike previous versions,
existing kernel configuration files do not need to be changed, except
when they reference device drivers that are listed in UPDATING.
Obtained from: //depot/projects/mpsafetty/...
Approved by: philip (ex-mentor)
Discussed: on the lists, at BSDCan, at the DevSummit
Sponsored by: Snow B.V., the Netherlands
dcons(4) fixed by: kan
implemented with macros. This patch improves code readability. Reasoning
behind kbdd_* is a "keyboard discipline".
List of macros is supposed to be complete--all methods of keyboard_switch
should have their respective macros from now on.
Functionally, this code should be no-op. My intention is to leave current
behaviour of code as is.
Glanced at by: rwatson
Reviewed by: emax, marcel
Approved by: cognet
- The output routine of low level console is not protected by any lock
by default.
- Increment and decrement of sc->write_in_progress are not atomic and
this may cause console hang.
- We also have many other states used by emulator that should be protected
by the lock.
- This change does not fix interspersed messages which PRINTF_BUFR_SIZE
kernel option should fix.
Approved by: re (bmah)
MFC after: 1 week
in syscons. This replaces a simple access semaphore that was assumed to be
protected by Giant but often was not. If two threads that were otherwise
SMP-safe called printf at the same time, there was a high likelyhood that
the semaphore would get corrupted and result in a permanently frozen video
console. This is similar to what is already done in the serial console
drivers.
and do some preparations for handling 12x22 fonts (currently lots of code
implies and/or hardcodes a font width of 8 pixels). This will be required
on sparc64 which uses a default font size of 12x22 in order to add font
loading and saving support as well as to use a syscons(4)-supplied mouse
pointer image.
This API breakage is committed now so it can be MFC'ed in time for 6.0
and later on upcoming framebuffer drivers destined for use on sparc64
and which are expected to rely on using font loading internally and on
a syscons(4)-supplied mouse pointer image can be easily MFC'ed to
RELENG_6 rather than requiring a backport.
Tested on: i386, sparc64, make universe
MFC after: 1 week
by explicitly setting sc->font_width, in the same
places where sc->font_size is set, instead of
relying on the default initialized value of 0 for sc->font_width.
PR: kern/84836
Reported by: Andrey V. Elsukov <bu7cher at yandex dot ru>
MFC after: 2 days
24, and 32 bit modes. To use that, syscons(4) must be built with
the compile time option 'options SC_PIXEL_MODE', and VESA support (a.k.a.
vesa.ko) must be either loaded, or be compiled into the kernel.
Do not return EINVAL when the mouse state is changed to what it already is,
which seems to cause problems when you have two mice attached, and
applications are not likely obtain useful information through the EINVAL
caused by showing the mouse pointer twice.
Teach vidcontrol(8) about mode names like MODE_<NUMBER>, where <NUMBER> is
the video mode number from the vidcontrol -i mode output. Also, revert the
video mode if something fails.
Obtained from: DragonFlyBSD
Discussed at: current@ with patch attached [1]
PR: kern/71142 [2]
Submitted by: Xuefeng DENG <dsnofe at msn com> [1],
Cyrille Lefevre <cyrille dot lefevre at laposte dot net> [2]
syscons(4) and its pseudo-devices don't get confused (including by
other device drivers) with the system controller devices which are
also termed 'sc' in the OFW tree (and which we probably want to
interface with hwpmc(4) one day).
- Move MD files into <arch>/<arch>.
- Move bus dependent files into <arch>/<bus>.
Rename some files to more suitable names.
Repo-copied by: peter
Discussed with: imp
for unknown events.
A number of modules return EINVAL in this instance, and I have left
those alone for now and instead taught MOD_QUIESCE to accept this
as "didn't do anything".
like this can be emulated by VT_SETMODEing to VT_PROCESS and never
releasing the vty, but this has a number of problems, most notably
that a process must stay resident for the lock to be in effect.
Reviewed by: roam, sheldonh
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.
Sorry john! (your next MFC will be a doosie!)
Reviewed by: peter@freebsd.org, dillon@freebsd.org
X-MFC after: ha ha ha ha
- When both SC_PIXEL_MODE and SC_NO_FONT_LOADING are defined,
quietly drop SC_NO_FONT_LOADING, because the pixel(raster)
console requires font.
- When SC_NO_FONT_LOADING is defined, force SC_ALT_MOUSE_IMAGE.
Without font, the arrow-shaped mouse cursor cannot be drawn.
- Fiddle and simplify some internal macros.
MFC after: 2 weeks
Replace the a.out emulation of 'struct linker_set' with something
a little more flexible. <sys/linker_set.h> now provides macros for
accessing elements and completely hides the implementation.
The linker_set.h macros have been on the back burner in various
forms since 1998 and has ideas and code from Mike Smith (SET_FOREACH()),
John Polstra (ELF clue) and myself (cleaned up API and the conversion
of the rest of the kernel to use it).
The macros declare a strongly typed set. They return elements with the
type that you declare the set with, rather than a generic void *.
For ELF, we use the magic ld symbols (__start_<setname> and
__stop_<setname>). Thanks to Richard Henderson <rth@redhat.com> for the
trick about how to force ld to provide them for kld's.
For a.out, we use the old linker_set struct.
NOTE: the item lists are no longer null terminated. This is why
the code impact is high in certain areas.
The runtime linker has a new method to find the linker set
boundaries depending on which backend format is in use.
linker sets are still module/kld unfriendly and should never be used
for anything that may be modular one day.
Reviewed by: eivind
- Split terminal emulation code from the main part of the driver so
that we can have alternative terminal emulator modules if we like in
the future. (We are not quite there yet, though.)
- Put sysmouse related code in a separate file, thus, simplifying the
main part of the driver.
As some files are added to the source tree, you need to run config(8)
before you compile a new kernel next time.
You shouldn't see any functional change by this commit; this is only
internal code reorganization.
fields in struct cdevsw:
d_stop moved to struct tty.
d_reset already unused.
d_devtotty linkage now provided by dev_t->si_tty.
These fields will be removed from struct cdevsw together with
d_params and d_maxio Real Soon Now.
The changes in this patch consist of:
initialize dev->si_tty in *_open()
initialize tty->t_stop
remove devtotty functions
rename ttpoll to ttypoll
a few adjustments to these changes in the generic code
a bump of __FreeBSD_version
add a couple of FreeBSD tags
- Remove sc_get_scr_stat(). It's not necessary anymore.
- Call ttymalloc() to allocate the struct tty for each vty, rather than
statically declaring an array of struct tty. We still need a statically
allocated struct tty for the first vty which is used for the kernel
console I/O, though.
- Likewise, call ttymalloc() for /dev/sysmouse and /dev/consolectl.
- Delete unnecessary test on the pointer struct tty *tp in some functions.
- Delete unused code in scmouse.c.
WARNING: this change requires you to recompile screen savers!
Diskslice/label code not yet handled.
Vinum, i4b, alpha, pc98 not dealt with (left to respective Maintainers)
Add the correct hook for devfs to kern_conf.c
The net result of this excercise is that a lot less files depends on DEVFS,
and devtoname() gets more sensible output in many cases.
A few drivers had minor additional cleanups performed relating to cdevsw
registration.
A few drivers don't register a cdevsw{} anymore, but only use make_dev().
- Correctly observe the variable `extra_history_size' when changing
the size of history (scroll back) buffer.
- Added sc_free_history_buffer().
Pointed out by: des
and insertion should affect the line the cursor is on only.
This change should have been committed together with syscons.c rev 1.308.
(I forgot to do so, when I committed syscons.c :-(
Pointed out by: sos
- Split syscons source code into manageable chunks and reorganize
some of complicated functions.
- Many static variables are moved to the softc structure.
- Added a new key function, PREV. When this key is pressed, the vty
immediately before the current vty will become foreground. Analogue
to PREV, which is usually assigned to the PrntScrn key.
PR: kern/10113
Submitted by: Christian Weisgerber <naddy@mips.rhein-neckar.de>
- Modified the kernel console input function sccngetc() so that it
handles function keys properly.
- Reorganized the screen update routine.
- VT switching code is reorganized. It now should be slightly more
robust than before.
- Added the DEVICE_RESUME function so that syscons no longer hooks the
APM resume event directly.
- New kernel configuration options: SC_NO_CUTPASTE, SC_NO_FONT_LOADING,
SC_NO_HISTORY and SC_NO_SYSMOUSE.
Various parts of syscons can be omitted so that the kernel size is
reduced.
SC_PIXEL_MODE
Made the VESA 800x600 mode an option, rather than a standard part of
syscons.
SC_DISABLE_DDBKEY
Disables the `debug' key combination.
SC_ALT_MOUSE_IMAGE
Inverse the character cell at the mouse cursor position in the text
console, rather than drawing an arrow on the screen.
Submitted by: Nick Hibma (n_hibma@FreeBSD.ORG)
SC_DFLT_FONT
makeoptions "SC_DFLT_FONT=_font_name_"
Include the named font as the default font of syscons. 16-line,
14-line and 8-line font data will be compiled in. This option replaces
the existing STD8X16FONT option, which loads 16-line font data only.
- The VGA driver is split into /sys/dev/fb/vga.c and /sys/isa/vga_isa.c.
- The video driver provides a set of ioctl commands to manipulate the
frame buffer.
- New kernel configuration option: VGA_WIDTH90
Enables 90 column modes: 90x25, 90x30, 90x43, 90x50, 90x60. These
modes are mot always supported by the video card.
PR: i386/7510
Submitted by: kbyanc@freedomnet.com and alexv@sui.gda.itesm.mx.
- The header file machine/console.h is reorganized; its contents is now
split into sys/fbio.h, sys/kbio.h (a new file) and sys/consio.h
(another new file). machine/console.h is still maintained for
compatibility reasons.
- Kernel console selection/installation routines are fixed and
slightly rebumped so that it should now be possible to switch between
the interanl kernel console (sc or vt) and a remote kernel console
(sio) again, as it was in 2.x, 3.0 and 3.1.
- Screen savers and splash screen decoders
Because of the header file reorganization described above, screen
savers and splash screen decoders are slightly modified. After this
update, /sys/modules/syscons/saver.h is no longer necessary and is
removed.
- Bring down the splash screen when a vty is opened for the first
time.
- Make sure the splash screen/screen saver is stopped before
switching vtys.
- Read and save initial values in the BIOS data area early.
VESA BIOS may change BIOS data values when switching modes.
- Fix missing '&' operator.
- Move ISA specific part of driver initialization to syscons_isa.c.
atkbd
- kbdtables.h is now in /sys/dev/kbd.
all
- Adjust for forthcoming alpha port. Submitted by: dfr
keyboard and video card drivers.
Because of the changes, you are required to update your kernel
configuration file now!
The files in sys/dev/syscons are still i386-specific (but less so than
before), and won't compile for alpha and PC98 yet.
syscons still directly accesses the video card registers here and
there; this will be rectified in the later stages.
- Express various sizes in bytes, rather than Kbytes, in the video
mode and adapter information structures.
- Fill 0 in the linear buffer size field if the linear frame buffer
is not available.
- Remove SW_VESA_USER ioctl. It is still experimetal and was not meant
to be released.
- Fix missing cast operator.
- Correctly handle pointers returned by the VESA BIOS. The pointers
may point to the area either in the BIOS ROM or in the buffer supplied
by the caller.
- Set the destructive cursor at the right moment.
