Add missing time.h to tty.c (from Ismail Donmez), also remove some stray
spaces.

Change UTF-8 combining to inspect the previous character at the cursor
position rather than keeping the last character from the input stream,
this is how most terminals work and fixes problems with displaying these
characters in vim. GitHub issue 3600.

Rewrite combined character handling to be more consistent and to support
newer Unicode combined characters (which we have to "know" are combined
since they are not width zero). GitHub issue 3600.

Add support for OSC 8 hyperlinks (a VTE extension now supported by other
terminals such as iTerm2). Originally written by me then extended and
completed by first Will Noble and later Jeff Chiang. GitHub issues 911,
2621, 2890, 3240.

Store time lines are scrolled into history and display in copy mode.

Add an ACL list for users connecting to the tmux socket. Users may be
forbidden from attaching, forced to attach read-only, or allowed to
attach read-write. A new command, server-access, configures the list.
tmux gets the user using getpeereid(3) of the client socket. Users must
still configure file system permissions manually. From Dallas Lyons and
others.

Report error if creating socket fails with -D.

Fix exit message if creating socket fails.

Fix warnings, from Jan Tache in GitHub issue 2692.

Tidy old jobs every hour instead of every 30 seconds.

Add a couple of helper functions, and flush imsgs on exit.

Fix some warnings, GitHub issue 2382.

Add a flag to make a client wait for an empty line before exiting in
control mode to avoid stray commands ending up in the shell.

Instead of sending all data to control mode clients as fast as possible,
add a limit of how much data will be sent to the client and try to use
it for panes with some degree of fairness. GitHub issue 2217, with
George Nachman.

xterm-keys has been on by default for five years and all other modern
terminals use these key sequences by default. Merge the code into the
main tty and input tree processing (converting the latter to use a tree
rather than a table at the same time) and make the option a no-op.

Add a -D flag to ask tmux not to daemonize, useful both for running a
debugger (lldb does not have follow-fork-mode) and for running with a
managed supervisor init system. GitHub issue 2190.

Change message log to be per server rather than per client and include
every command that is run.

Add 'e' key in buffer mode to open the buffer in an editor.

When the server socket is given by the user with -S, create it with
umask 177 instead of 117 because it may not be in a safe directory like
the default directory in /tmp. The user can chmod it more open after it
is created if they want.

Expand command formats in %if and move the config file loading later (to
when the first client has identified) so all the client formats are
available, fixes problems reported by Thomas Sattler.

Do not load the config file if the server is exiting because it failed
to start, otherwise commands like lsk which start the server again can
end up looping infinitely. Also make the first client exit
correctly. Problem reported by Wael M Nasreddine.

Replace the various identical error callbacks with a single one in cmd-queue.c.

Break new window and pane creation common code from various commands and
window.c into a separate file spawn.c.

Move job struct into job.c.

SESSION_UNATTACHED flag is no longer necessary now we have an attached
count instead.

session_groups can be static also.

Add a missing client-detached hook when the server shuts down, and do
not exit until jobs started from run-shell/if-shell have finished (add a
job flags member and a flag to indicate other jobs). GitHub issue 1245.

Add exit-empty option to exit server if no sessions (defaults to on).

Report better error from server when socket create fails, GitHub issue
1201.

Show exit status and time in the remain-on-exit pane text, mostly from
Timo Boettcher in GitHub issue 1103.

Because ignore SIGCHLD early, letting signal_del restore it doesn't work
correctly, so set it explicitly back to default (and the others for good
measure).

Block signals between forking and clearing signal handlers (or calling
event_reinit) - if the child gets a signal and fires the libevent signal
handler during this period it could write a signal into the parent's
signal pipe. GitHub issue 1001 from Aaron van Geffen.

Move signal code into proc.c.

Some extra logging to show why tmux might exit.

Do not close panes until process has exited and any outstanding data
has been written to the pipe-pane event if there is one. GitHub issue 991.

Support SIGUSR2 to stop and start logging for an existing server. Also
we currently only have two log levels so just use -v and -vv rather than
-v and -vvvv, and clarify the man page entry for -v.

Memory leaks, from David CARLIER.

Make the cmd_find_* functions more obvious when looking for a client,
rather than having it inside other functions. Should be no change to the
way targets are resolved just yet.

History needs to be loaded after config parsing is done - now that
commands are queued, that's in cfg_done not after start_cfg finishes.

If a #() command doesn't exit, use its most recent line of output (it
must be a full line). Don't let it redraw the status line more than once
a second.

Requested by someone about 10 years ago...

Instead of numbering session groups, give them a name which may be given
to -t instead of a target session. Also allow them to contain only one
session.

Fixed keys for choose mode, and remove the last mode keys bits.

Do not execute commands for a client until it has identified, fixes
problem reported by Frank Terbeck.

Notifys can go via the command queue instead of using their own queue.

Rewrite command queue handling. Each client still has a command queue,
but there is also now a global command queue. Instead of command queues
being dispatched on demand from wherever the command happens to be
added, they are now all dispatched from the top level server
loop. Command queues may now also include callbacks as well as commands,
and items may be inserted after the current command as well as at the end.

This all makes command queues significantly more predictable and easier
to use, and avoids the complex multiple nested command queues used by
source-file, if-shell and friends.

A mass rename of struct cmdq to a better name (cmdq_item probably) is
coming.

Drain notifys once at the end of the server loop instead of doing it
from the end of every command queue (which could be nested).

Loads more static, except for cmd-*.c and window-*.c.

tmux: only consider ACCESSPERMS for setting mode on socket_path.

it explicitly removes any S_ISUID|S_ISGID|S_ISTXT bits, instead of letting
pledge(2) silenciously remove them.

ok nicm@ beck@ deraadt@

Bump the listen() backlog up, some people have scripts that run up a lot
of clients quickly.

I no longer use my SourceForge address so replace it.

Add infrastructure to work out the best target given a pane or window
alone and use it to add pane_died and pane_exited hooks.

Make the marked pane a cmd_find_state.

Do lock failures slightly better, return a special value so we don't
unlink the wrong thing.

Remove the -I part of show-messages which isn't really that useful; the
server start time can now be accessed with a new start_time format (use:
tmux display -p '#{t:start_time}')

Make the log stuff a bit tidier with some helper functions.

Add getpw to pledge, makes tmux work in YP environments, discovered by
matthieu, ok deraadt

Use __unused rather than rolling our own.

Accidentally turned off pledge, turn it back on.

Push stdout and stderr to clients more aggressively, and add an event to
continue if the send fails.

Tidy utf8.c a little: build table on first use, and make utf8_width take
a u_int rather than splitting and then combining again in utf8_split.

The output log is only useful once and it means creating a file, so open
it once at startup instead of in every call to tty_open.

Move struct options into options.c.

Break the common process set up, event loop and imsg dispatch code
between server and client out into a separate internal API. This will
make it easier to add another process.

tmux can call pledge() in main with large set and then reduce it
slightly in the server to "stdio rpath wpath cpath fattr unix recvfd
proc exec tty ps".

This should not be changed.

Rename shutdown to exit.

Userspace doesn't need to use SUN_LEN(): connect() and bind() must accept
sizeof(struct sockaddr_un), so do the simple, portable thing

ok beck@ deraadt@

Move initial conf load into cfg.c.

Event base does not need to be global.

We already loop over the windows in server_client_loop, so don't do it
again in server_loop just to check names.

Move alerts onto events rather than checking every loop.

Remove unused prototypes.

Per-session timers for locking, and remove the global one-second timer.

Remove the lock-server option which is a bit redundant, it isn't that
different without it.

Give clock mode its own timer.

Run status update on a per-client timer at status-interval.

Move format job cleanup onto its own timer.

Add an option (history-file) for a file to save/restore command prompt
history, from Olof-Joachim Frahm.

Similarly, for sessions use a callback to free rather than checking
every loop.

Instead of putting dead clients on a list and checking it every loop,
use event_once to queue a callback to deal with them. Also dead clients
with references would never actually be freed because the wrap-up
functions (the callback for stdin, or status_prompt_clear) would never
be called. So call them in server_client_lost.

Add support for a single "marked pane". There is one marked pane in the
server at a time; it may be toggled or cleared with select-pane -m and
-M (the border is highlighted). A new target '~' or '{marked}' specifies
the marked pane to commands and it is the default target for the
swap-pane and join-pane -s flag (this makes them much simpler to use -
mark the source pane and then change to the target pane to run swapp or
joinp).

Clear signal handlers before event_reinit as apparently it can otherwise
cause libevent to go strange.

does not need syslog.h

Move the jobs output cache into the formats code so that #() work more
generally (for example, again working in set-titles-string).

Convert clients list into a TAILQ.

Change the windows array into an RB tree and fix some places where we
were only looking at the first winlink for a window in a session.

window_index is only used in one place (window_destroy) so inline it there.

Do not die on USR1 if any of the socket parent directories are
missing. Reported by Robin Powell.

Add pane_dead_status for exit status of dead panes.

Move cfg_causes local into cfg.c and remove struct causelist.

Wake up any clients waiting with the wait-for command when the server
exits.

lockf is entirely useless and it was a mistake to change to it, go back
to using flock which actually works sensibly. Also always retry the lock
to fix a potential race, and add some extra logging.

Now that cmdlists are reference counted, there is no need for two-step
deletion via the dead_key_bindings tree. From Keith Amling.

There is no longer a need for a paste_stack struct or for global_buffers
to be global. Move to paste.c.

Some more long lines.

Do not run any command line command from the client which starts the
server until after the configuration file completes. This prevents it
racing against run-shell or if-shell in .tmux.conf that run in the
background.

Rename global configuration define.

Add a command queue to standardize and simplify commands that call other
commands and allow a command to block execution of subsequent
commands. This allows run-shell and if-shell to be synchronous which has
been much requested.

Each client has a default command queue and commands are consumed one at
a time from it. A command may suspend execution from the queue by
returning CMD_RETURN_WAIT and then resume it by calling cmd_continue() -
for example run-shell does this from the callback that is fired after
the job is freed.

When the command queue becomes empty, command clients are automatically
exited (unless attaching). A callback is also fired - this is used for
nested commands in, for example, if-shell which can block execution of
the client's cmdq until a new cmdq becomes empty.

Also merge all the old error/info/print functions together and lose the
old curclient/cmdclient distinction - a cmdq is bound to one client (or
none if in the configuration file), this is a command client if
c->session is NULL otherwise an attached client.

No more lint means no more ARGSUSED.

Fix argument order in a log statement.

Use a utility function for common code to show errors in config file,
from Thomas Adam.

xfree is not particularly helpful, remove it. From Thomas Adam.

Stop accepting new clients for 1 second on EMFILE/ENFILE. Based on
ongoing fixes to other daemons by Theo.

Use a lock file and flock() to serialize server start, avoids problems
when running a bunch of tmux from cron at the same time. Based on a diff
from Tim Ruehsen.

Give each pane created in a tmux server a unique id (starting from 0),
put it in the TMUX_PANE environment variable and accept it as a
target. Suggested by and with testing and tweaks from Ben Boeckel.

Use LIST_* not SLIST_*.

Move all calls to fcntl(...O_NONBLOCK) into a function and clear the
flag on the stdio file descriptors before closing them (fixes things
like "tmux ls && cat").

Don't reset the activity timer for unattached sessions every second,
this screws up the choice of most-recently-used. Instead, break the time
update into a little function and do it when the session is attached.

Pointed out by joshe@.

Change from a per-session stack of buffers to one global stack which is
much more convenient and also simplifies lot of code. This renders
copy-buffer useless and makes buffer-limit now a server option.

By Tiago Cunha.

Store sessions in an RB tree by name rather than a list, this is tidier
and allows them to easily be shown sorted in various lists
(list-sessions/choose-sessions).

Keep a session index which is used in a couple of places internally but
make it an ever-increasing number rather than filling in gaps with new
sessions.

Merge the before and after attach client code into one in client.c
(instead of two in tmux.c and client.c).

Trying to set FD_CLOEXEC on every fd is a lost cause, just use
closefrom() before exec.

Two new options:

- server option "exit-unattached" makes the server exit when no clients
are attached, even if sessions are present;

- session option "destroy-unattached" destroys a session once no clients
are attached to it.

These are useful for preventing tmux remaining in the background where
it is undesirable and when using tmux as a login shell to keep a limit
on new sessions.

Modify the permissions on the socket when adding or removing +x to show
attached sessions, rather than replacing them.

Do not call event_del() for signals after fork(), just use sigaction()
directly instead - calling libevent functions after fork() w/o
event_reinit() is a bad idea, even if in this case it was harmless.

switch back to kqueue for now, since (a) kqueue has been fixed to deal
with strange devices and (b) since there appears to be a bull in the
poll code in libevent as well...
requested by nicm who is away

kqueue(2) is currently broken when used with /dev/null and a few other
devices.

An upcoming fix for some problems with the client stdout/stderr handling
relies on it working, so make tmux force libevent to use poll(2) via
EVENT_NOKQUEUE, until we have fixed kqueue.

Give tmux sockets (but not the containing folder) group
permissions. This allows hardlinks to the sockets to be used more
easily.

Put this back in with the initialisation in the right order.

Revert last change, it appears to be broken somehow.

Make signal handler setup/teardown two common functions instead of six,
and reset SIGCHLD after fork to fix problems with some shells. From
Romain Francois.

Merge copy mode and output mode, dropping the latter. Idea and code from
Micah Cowan.

Nuke unused variable.

Use the array.h code for the causes list.

Instead of bailing out on the first configuration file error, carry on,
collecting all the errors, then start with the active window in more mode
displaying them.

Ignore SIGHUP as well.

Massive spaces->tabs and trailing whitespace cleanup, hopefully for the last
time now I've configured emacs to make them displayed in really annoying
colours...

Close the pane if the process died due to a signal, not just if it exited
normally.

Remove a couple of unused arguments where possible, and add /* ARGSUSED */ to
the rest to reduce lint output.

Destroy panes immediately rather than checking them all every loop.

Free the pane bufferevent when the fd is closed (the signal could come before
the error callback).

Only need to chmod +x or -x the socket when a client is created, lost or
attached, rather than every event loop.

EVLOOP_ONCE takes care of the wakeup, so no need to call event_loopexit(NULL).

Now all timers are events, there is no longer any need to wake up every 50 ms -
only wake up when an event happens.

Move status timer check into the global once-per-second timer, this could maybe
be done better but one every second is better than once every 50 ms.

Don't reenlist the client imsg event every loop, instead have a small function
to it and call it after the event triggers or after a imsg is added.

Tell the client to exit on configuration file error.

Convert the window pane (pty master side) fd over to use a bufferevent.

The evbuffer API is very similar to the existing tmux buffer API so this was
remarkably painless. Not many possible ways to do it, I suppose.

Call event_init() before loading the config file, since potentially it could
set up events.

Switch jobs over to use a bufferevent.

Initial changes to move tmux to libevent.

This moves the client-side loops are pretty much fully over to event-based only
(tmux.c and client.c) but server-side (server.c and friends) treats libevent as
a sort of clever poll, waking up after every event to run various things.

Moving the server stuff over to bufferevents and timers and so on will come
later.

Change session and client activity and creation time members to have more
meaningful names.

Also, remove the code to try and update the session activity time for the
command client when a command message is received as is pointless because it
des not have a session.

Reorder slightly to tidy code.

Move the poll registration functions into the server-*.c files.

tabs are better; ok nicm

Clear signal flags /before/ taking action and continue afterwards to reduce
chance of dropping signals. Pointed out by deraadt@.

Split the server code handling clients, jobs and windows off into separate
files from server.c (merging server-msg.c into the client file) and rather than
iterating over each set after poll(), allow a callback to be specified when the
fd is added and just walk once over the returned pollfds calling each callback
where needed.

More to come, getting this in so it is tested.

When a session is unattached, reset its activity timer to prevent it locking
instantly when reattached.

Similarly add a tty_cursor_pane function to tidy up most of the calls.

_absolute is redundant, just use tty_region.

Cleanup: use two functions for region setting, one for absolute and one inside
pane.

Add a pipe-pane command to allow a pane to be piped to a shell command, for
example:

pipe-pane 'cat >~/out'

No arguments stops outputing and closes the pipe; the -o flag toggles a pipe
and on and off (useful for key bindings).

Suggested by espie@.

Switch run-shell over to queue the command in the background like #().

Collect status from dead jobs and don't invoke the callback until both
all input (the socket is closed) and status is available.

Clean up by introducing a wrapper struct for mouse clicks rather than passing
three u_chars around.

As a side-effect this fixes incorrectly rejecting high cursor positions
(because it was comparing them as signed char), reported by Tom Doherty.

Braek some bits out of server_fill_client() that aren't really related to
polling into their own function.

Put all jobs on a global all_jobs list and use that in server.c instead of
running through all the clients.

Rather than running status-left, status-right and window title #() with popen
immediately every redraw, queue them up and run them in the background,
starting each once every status-interval. The actual status line uses the
output from the last run.

This brings several advantages:

- tmux itself may be called from inside #() without causing the server to hang;
- likewise, sleep or similar doesn't cause the server to block;
- commands aren't run excessively often when redrawing;
- commands shared by status-left and status-right, or used multiple times, will
only be run once.

run-shell and if-shell still use system()/popen() but will be changed over to
use this too later.

New option, mouse-select-pane. If on, the mouse may be used to select the
current pane.

Suggested by sthen@ and also by someone else ages ago who I have forgotten.

Add "grouped sessions" which have independent name, options, current window and
so on but where the linked windows are synchronized (ie creating, killing
windows and so on are mirrored between the sessions). A grouped session may be
created by passing -t to new-session.

Had this around for a while, tested by a couple of people.

Support for individual session idle time locking. May be enabled by turning off
the lock-server option (it is on by default). When this is off, each session
locks when it has been idle for the lock-after-time setting. When on, the
entire server locks when ALL sessions have been idle for their individual
lock-after-time settings.

This replaces one global-only option (lock-after-time) with another
(lock-server), but the default behaviour is usually preferable so there don't
seem to be many alternatives.

Diff/idea largely from Thomas Adam, tweaked by me.

Instead of passing a struct pollfd ** around through various functions, build
them into a tree and then convert into a flat poll array before and after poll.

This adds a little code but should reduce annoying problems with ordering when
adding new things that also need to be polled.

If no target client is specified to commands which accept one, try to guess the
current client, in a similar manner to how sessions already work: if the
current session can be established and has only one client, use that; otherwise
use the most recently created client.

Don't allow locked or suspended clients to limit the size of active clients.

On SIGTERM, just abandon any suspended/locked clients and leave them to it,
otherwise the server will hang around (refusing new connections) until they
exit properly.

Remove the internal tmux locking and instead detach each client and run the
command specified by a new option "lock-command" (by default "lock -np") in
each client.

This means each terminal has to be unlocked individually but simplifies the
code and allows the system password to be used to unlock.

Note that the set-password command is gone, so it will need to be removed from
configuration files, and the -U command line flag has been removed.

This is the third protocol version change so again it is best to stop the tmux
server before upgrading.

Permit multiple prefix keys to be defined, separated by commas, for example:

set -g prefix ^a,^b

Any key in the list acts as the prefix. The send-prefix command always sends
the first key in the list.

Regularise some fatal messages.

New option, set-titles-string, to allow the window title to be specified (as
for status-left/right) if set-titles is on. Also only update the title when the
status line is being redrawn.

The default terminal size should be 80x24, not 80x25.

Nuke unused server_client_index function, pointed out by martynas@.

Doh, trim variables unused now.

Tidy some common code for destroying sessions into a new function.

Permit options such as status-bg to be configured using the entire 256 colour
palette by setting "colour0" to "colour255".

While the display-panes indicator is on screen, make the number keys select the
pane with that index.

Reference count clients and sessions rather than relying on a saved index for
cmd-choose-*.

Tiny cleanup.

ok nicm@

Only redraw all clients once when the backoff timer expires rather than every
second all the time.

Reported by Simon Nicolussi.

Tell the user when sleeping due to password backoff.

When shutting down the server, expect clients to be polite and exit when asked
with the right message.

Add a new display-panes command, with two options (display-panes-colour and
display-panes-time), which displays a visual indication of the number of each
pane.

Don't call tty_free unless the client is a terminal, otherwise tty_init hasn't
been called and it may end up doing close(0). From Kalle Olavi Niemitalo.

When using source-file, run the commands in the context of the source-file
command rather than with no context. This makes things like attach work from a
file.

Whoops, getting the comparison the right way round is usually recommended.

options_get_number() is relatively expensive and a check for dead panes happens
a lot more often than actually finding one, so instead of getting the option
for every check, get it for every dead window found.

Reset attributes as well as scroll region before poll(2) and add a big comment
explaining why.

Initialise log_fd to -1, prevents spurious disconnection of the client when it
ends up as fd 0 (likely if the server is started with "tmux start").

Also add some extra debugging messages to server.c.

Drop the no_stop argument to tty_close and tty_free in favour of a flag in the
tty struct.

Switch tmux to use imsg. This is the last major change to make the
client-server protocol more resilient and make the protocol versioning work
properly. In future, the only things requiring a protocol version bump will be
changes in the message structs, and (when both client and server have this
change) mixing different versions should nicely report an error message.

As a side effect this also makes the code tidier, fixes a problem with the way
errors reported during server startup were handled, and supports fd passing
(which will be used in future).

Looked over by eric@, thanks.

Please note that mixing a client with this change with an older server or vice
versa may cause tmux to crash or hang - tmux should be completely exited before
upgrading.

Reset the attributes after drawing all or part of the screen, and reset the
region before poll(2). This reduces (but does not eliminate) the chance of the
attributes not being normal if tmux is disconnected without warning (ssh ~.,
reboot from inside, etc).

If there is an error in the configuration file, don't just exit(1) as this can
cause the client to hang. Instead, send the error message, then mark the client
as bad and start a normal shutdown so the server exits once the error is
written.

This also allows some code duplicating daemon(3) to be trimmed and logging to
begin earlier.

Prompted by Theo noticing the behaviour on error wasn't documented.

Next step towards customisable mode keys: build each default table of keys into
a named tree on start and use that for lookups. Also add command to string
translation tables and modify list-keys to show the the mode key bindings (new
-t argument).

Permit commands to be bound to key presses without the prefix key first. The
new -n flag to bind-key and unbind-key sets or removes these bindings, and
list-key shows them in []s.

Make some functions which return unused values void (mostly found by lint) and
tweak a redundant expression in window_pane_set_mode.

Display the number of failed password attempts (if any) when the server is
locked. From Tom Doherty.

Improved layout code.

Each window now has a tree of layout cells associated with it. In this tree,
each node is either a horizontal or vertical cell containing a list of other
cells running from left-to-right or top-to-bottom, or a leaf cell which is
associated with a pane.

The major functional changes are:

- panes may now be split arbitrarily both horizontally (splitw -h, C-b %) and
vertically (splitw -v, C-b ");
- panes may be resized both horizontally and vertically (resizep -L/-R/-U/-D,
bound to C-b left/right/up/down and C-b M-left/right/up/down);
- layouts are now applied and then may be modified by resizing or splitting
panes, rather than being fixed and reapplied when the window is resized or
panes are added;
- manual-vertical layout is no longer necessary, and active-only layout is gone
(but may return in future);
- the main-pane layouts now reduce the size of the main pane to fit all panes
if possible.

Thanks to all who tested.

Add three new session options: visual-activity, visual-bell, visual-content. If
these are enabled (and the monitor-activity, bell-actio and monitor-content
options are configurated appropriately), when activity, a bell, or content is
detected, a message is shown.

Also tidy up the bell/activity/content code in server.c slightly and fix a
couple of errors.

Instead of faking up a status line in status_redraw, use the same code to
redraw it as to draw the entire screen, just skip all lines but the last.

This makes horizontal split redraw properly when the status line is off.

Creating a key binding which replaces itself (such as "bind x bind x lsw")
frees the command list bound to the key while it is still being executed,
leading to a use after free. To prevent this, create a dead keys list and defer
freeing replaced or removed key bindings until the main loop when the key
binding will have finished executing.

Found by Johan Friis when creating a key binding to reload his configuration
file.

If it exist, load a system-wide configuration file /etc/tmux.conf before any
user-specified one.

Rename the global options variables to be shorter and to make session options
clear. No functional change, getting this out of the way to make later options
changes easier.

After logging (if enabled) is switched to file, there is no reason to keep
stdin/stdout/stderr active, so dup them to /dev/null.

Remove some dead assignments, found by sthen with clang.

Change find-window and monitor-content to use fnmatch(3). For convenience and
compatibility, *s are implicitly added at the start and end of the pattern.

Also display the line number and the entire line in the results, and lose the
nasty section_string function and the now empty util.c file.

Initially from Tiago Cunha.

Make remain-on-exit work again when there is only one pane left, which was
broken sometime during the pane/layout changes. Reported/tested by Iain Morgan,
thanks.

Import tmux, a terminal multiplexor allowing (among other things) a single
terminal to be switched between several different windows and programs
displayed on one terminal be detached from one terminal and moved to another.

ok deraadt pirofti

Change UTF-8 combining to inspect the previous character at the cursor
position rather than keeping the last character from the input stream,
this is how most terminals work and fixes problems with displaying these
characters in vim. GitHub issue 3600.

Rewrite combined character handling to be more consistent and to support
newer Unicode combined characters (which we have to "know" are combined
since they are not width zero). GitHub issue 3600.

Add support for OSC 8 hyperlinks (a VTE extension now supported by other
terminals such as iTerm2). Originally written by me then extended and
completed by first Will Noble and later Jeff Chiang. GitHub issues 911,
2621, 2890, 3240.

Store time lines are scrolled into history and display in copy mode.

Add an ACL list for users connecting to the tmux socket. Users may be
forbidden from attaching, forced to attach read-only, or allowed to
attach read-write. A new command, server-access, configures the list.
tmux gets the user using getpeereid(3) of the client socket. Users must
still configure file system permissions manually. From Dallas Lyons and
others.

Report error if creating socket fails with -D.

Fix exit message if creating socket fails.

Fix warnings, from Jan Tache in GitHub issue 2692.

Tidy old jobs every hour instead of every 30 seconds.

Add a couple of helper functions, and flush imsgs on exit.

Fix some warnings, GitHub issue 2382.

Add a flag to make a client wait for an empty line before exiting in
control mode to avoid stray commands ending up in the shell.

Instead of sending all data to control mode clients as fast as possible,
add a limit of how much data will be sent to the client and try to use
it for panes with some degree of fairness. GitHub issue 2217, with
George Nachman.

xterm-keys has been on by default for five years and all other modern
terminals use these key sequences by default. Merge the code into the
main tty and input tree processing (converting the latter to use a tree
rather than a table at the same time) and make the option a no-op.

Add a -D flag to ask tmux not to daemonize, useful both for running a
debugger (lldb does not have follow-fork-mode) and for running with a
managed supervisor init system. GitHub issue 2190.

Change message log to be per server rather than per client and include
every command that is run.

Add 'e' key in buffer mode to open the buffer in an editor.

When the server socket is given by the user with -S, create it with
umask 177 instead of 117 because it may not be in a safe directory like
the default directory in /tmp. The user can chmod it more open after it
is created if they want.

Expand command formats in %if and move the config file loading later (to
when the first client has identified) so all the client formats are
available, fixes problems reported by Thomas Sattler.

Do not load the config file if the server is exiting because it failed
to start, otherwise commands like lsk which start the server again can
end up looping infinitely. Also make the first client exit
correctly. Problem reported by Wael M Nasreddine.

Replace the various identical error callbacks with a single one in cmd-queue.c.

Break new window and pane creation common code from various commands and
window.c into a separate file spawn.c.

Move job struct into job.c.

SESSION_UNATTACHED flag is no longer necessary now we have an attached
count instead.

session_groups can be static also.

Add a missing client-detached hook when the server shuts down, and do
not exit until jobs started from run-shell/if-shell have finished (add a
job flags member and a flag to indicate other jobs). GitHub issue 1245.

Add exit-empty option to exit server if no sessions (defaults to on).

Report better error from server when socket create fails, GitHub issue
1201.

Show exit status and time in the remain-on-exit pane text, mostly from
Timo Boettcher in GitHub issue 1103.

Because ignore SIGCHLD early, letting signal_del restore it doesn't work
correctly, so set it explicitly back to default (and the others for good
measure).

Block signals between forking and clearing signal handlers (or calling
event_reinit) - if the child gets a signal and fires the libevent signal
handler during this period it could write a signal into the parent's
signal pipe. GitHub issue 1001 from Aaron van Geffen.

Move signal code into proc.c.

Some extra logging to show why tmux might exit.

Do not close panes until process has exited and any outstanding data
has been written to the pipe-pane event if there is one. GitHub issue 991.

Support SIGUSR2 to stop and start logging for an existing server. Also
we currently only have two log levels so just use -v and -vv rather than
-v and -vvvv, and clarify the man page entry for -v.

Memory leaks, from David CARLIER.

Make the cmd_find_* functions more obvious when looking for a client,
rather than having it inside other functions. Should be no change to the
way targets are resolved just yet.

History needs to be loaded after config parsing is done - now that
commands are queued, that's in cfg_done not after start_cfg finishes.

If a #() command doesn't exit, use its most recent line of output (it
must be a full line). Don't let it redraw the status line more than once
a second.

Requested by someone about 10 years ago...

Instead of numbering session groups, give them a name which may be given
to -t instead of a target session. Also allow them to contain only one
session.

Fixed keys for choose mode, and remove the last mode keys bits.

Do not execute commands for a client until it has identified, fixes
problem reported by Frank Terbeck.

Notifys can go via the command queue instead of using their own queue.

Rewrite command queue handling. Each client still has a command queue,
but there is also now a global command queue. Instead of command queues
being dispatched on demand from wherever the command happens to be
added, they are now all dispatched from the top level server
loop. Command queues may now also include callbacks as well as commands,
and items may be inserted after the current command as well as at the end.

This all makes command queues significantly more predictable and easier
to use, and avoids the complex multiple nested command queues used by
source-file, if-shell and friends.

A mass rename of struct cmdq to a better name (cmdq_item probably) is
coming.

Drain notifys once at the end of the server loop instead of doing it
from the end of every command queue (which could be nested).

Loads more static, except for cmd-*.c and window-*.c.

tmux: only consider ACCESSPERMS for setting mode on socket_path.

it explicitly removes any S_ISUID|S_ISGID|S_ISTXT bits, instead of letting
pledge(2) silenciously remove them.

ok nicm@ beck@ deraadt@

Bump the listen() backlog up, some people have scripts that run up a lot
of clients quickly.

I no longer use my SourceForge address so replace it.

Add infrastructure to work out the best target given a pane or window
alone and use it to add pane_died and pane_exited hooks.

Make the marked pane a cmd_find_state.

Do lock failures slightly better, return a special value so we don't
unlink the wrong thing.

Remove the -I part of show-messages which isn't really that useful; the
server start time can now be accessed with a new start_time format (use:
tmux display -p '#{t:start_time}')

Make the log stuff a bit tidier with some helper functions.

Add getpw to pledge, makes tmux work in YP environments, discovered by
matthieu, ok deraadt

Use __unused rather than rolling our own.

Accidentally turned off pledge, turn it back on.

Push stdout and stderr to clients more aggressively, and add an event to
continue if the send fails.

Tidy utf8.c a little: build table on first use, and make utf8_width take
a u_int rather than splitting and then combining again in utf8_split.

The output log is only useful once and it means creating a file, so open
it once at startup instead of in every call to tty_open.

Move struct options into options.c.

Break the common process set up, event loop and imsg dispatch code
between server and client out into a separate internal API. This will
make it easier to add another process.

tmux can call pledge() in main with large set and then reduce it
slightly in the server to "stdio rpath wpath cpath fattr unix recvfd
proc exec tty ps".

This should not be changed.

Rename shutdown to exit.

Userspace doesn't need to use SUN_LEN(): connect() and bind() must accept
sizeof(struct sockaddr_un), so do the simple, portable thing

ok beck@ deraadt@

Move initial conf load into cfg.c.

Event base does not need to be global.

We already loop over the windows in server_client_loop, so don't do it
again in server_loop just to check names.

Move alerts onto events rather than checking every loop.

Remove unused prototypes.

Per-session timers for locking, and remove the global one-second timer.

Remove the lock-server option which is a bit redundant, it isn't that
different without it.

Give clock mode its own timer.

Run status update on a per-client timer at status-interval.

Move format job cleanup onto its own timer.

Add an option (history-file) for a file to save/restore command prompt
history, from Olof-Joachim Frahm.

Similarly, for sessions use a callback to free rather than checking
every loop.

Instead of putting dead clients on a list and checking it every loop,
use event_once to queue a callback to deal with them. Also dead clients
with references would never actually be freed because the wrap-up
functions (the callback for stdin, or status_prompt_clear) would never
be called. So call them in server_client_lost.

Add support for a single "marked pane". There is one marked pane in the
server at a time; it may be toggled or cleared with select-pane -m and
-M (the border is highlighted). A new target '~' or '{marked}' specifies
the marked pane to commands and it is the default target for the
swap-pane and join-pane -s flag (this makes them much simpler to use -
mark the source pane and then change to the target pane to run swapp or
joinp).

Clear signal handlers before event_reinit as apparently it can otherwise
cause libevent to go strange.

does not need syslog.h

Move the jobs output cache into the formats code so that #() work more
generally (for example, again working in set-titles-string).

Convert clients list into a TAILQ.

Change the windows array into an RB tree and fix some places where we
were only looking at the first winlink for a window in a session.

window_index is only used in one place (window_destroy) so inline it there.

Do not die on USR1 if any of the socket parent directories are
missing. Reported by Robin Powell.

Add pane_dead_status for exit status of dead panes.

Move cfg_causes local into cfg.c and remove struct causelist.

Wake up any clients waiting with the wait-for command when the server
exits.

lockf is entirely useless and it was a mistake to change to it, go back
to using flock which actually works sensibly. Also always retry the lock
to fix a potential race, and add some extra logging.

Now that cmdlists are reference counted, there is no need for two-step
deletion via the dead_key_bindings tree. From Keith Amling.

There is no longer a need for a paste_stack struct or for global_buffers
to be global. Move to paste.c.

Some more long lines.

Do not run any command line command from the client which starts the
server until after the configuration file completes. This prevents it
racing against run-shell or if-shell in .tmux.conf that run in the
background.

Rename global configuration define.

Add a command queue to standardize and simplify commands that call other
commands and allow a command to block execution of subsequent
commands. This allows run-shell and if-shell to be synchronous which has
been much requested.

Each client has a default command queue and commands are consumed one at
a time from it. A command may suspend execution from the queue by
returning CMD_RETURN_WAIT and then resume it by calling cmd_continue() -
for example run-shell does this from the callback that is fired after
the job is freed.

When the command queue becomes empty, command clients are automatically
exited (unless attaching). A callback is also fired - this is used for
nested commands in, for example, if-shell which can block execution of
the client's cmdq until a new cmdq becomes empty.

Also merge all the old error/info/print functions together and lose the
old curclient/cmdclient distinction - a cmdq is bound to one client (or
none if in the configuration file), this is a command client if
c->session is NULL otherwise an attached client.

No more lint means no more ARGSUSED.

Fix argument order in a log statement.

Use a utility function for common code to show errors in config file,
from Thomas Adam.

xfree is not particularly helpful, remove it. From Thomas Adam.

Stop accepting new clients for 1 second on EMFILE/ENFILE. Based on
ongoing fixes to other daemons by Theo.

Use a lock file and flock() to serialize server start, avoids problems
when running a bunch of tmux from cron at the same time. Based on a diff
from Tim Ruehsen.

Give each pane created in a tmux server a unique id (starting from 0),
put it in the TMUX_PANE environment variable and accept it as a
target. Suggested by and with testing and tweaks from Ben Boeckel.

Use LIST_* not SLIST_*.

Move all calls to fcntl(...O_NONBLOCK) into a function and clear the
flag on the stdio file descriptors before closing them (fixes things
like "tmux ls && cat").

Don't reset the activity timer for unattached sessions every second,
this screws up the choice of most-recently-used. Instead, break the time
update into a little function and do it when the session is attached.

Pointed out by joshe@.

Change from a per-session stack of buffers to one global stack which is
much more convenient and also simplifies lot of code. This renders
copy-buffer useless and makes buffer-limit now a server option.

By Tiago Cunha.

Store sessions in an RB tree by name rather than a list, this is tidier
and allows them to easily be shown sorted in various lists
(list-sessions/choose-sessions).

Keep a session index which is used in a couple of places internally but
make it an ever-increasing number rather than filling in gaps with new
sessions.

Merge the before and after attach client code into one in client.c
(instead of two in tmux.c and client.c).

Trying to set FD_CLOEXEC on every fd is a lost cause, just use
closefrom() before exec.

Two new options:

- server option "exit-unattached" makes the server exit when no clients
are attached, even if sessions are present;

- session option "destroy-unattached" destroys a session once no clients
are attached to it.

These are useful for preventing tmux remaining in the background where
it is undesirable and when using tmux as a login shell to keep a limit
on new sessions.

Modify the permissions on the socket when adding or removing +x to show
attached sessions, rather than replacing them.

Do not call event_del() for signals after fork(), just use sigaction()
directly instead - calling libevent functions after fork() w/o
event_reinit() is a bad idea, even if in this case it was harmless.

switch back to kqueue for now, since (a) kqueue has been fixed to deal
with strange devices and (b) since there appears to be a bull in the
poll code in libevent as well...
requested by nicm who is away

kqueue(2) is currently broken when used with /dev/null and a few other
devices.

An upcoming fix for some problems with the client stdout/stderr handling
relies on it working, so make tmux force libevent to use poll(2) via
EVENT_NOKQUEUE, until we have fixed kqueue.

Give tmux sockets (but not the containing folder) group
permissions. This allows hardlinks to the sockets to be used more
easily.

Put this back in with the initialisation in the right order.

Revert last change, it appears to be broken somehow.

Make signal handler setup/teardown two common functions instead of six,
and reset SIGCHLD after fork to fix problems with some shells. From
Romain Francois.

Merge copy mode and output mode, dropping the latter. Idea and code from
Micah Cowan.

Nuke unused variable.

Use the array.h code for the causes list.

Instead of bailing out on the first configuration file error, carry on,
collecting all the errors, then start with the active window in more mode
displaying them.

Ignore SIGHUP as well.

Massive spaces->tabs and trailing whitespace cleanup, hopefully for the last
time now I've configured emacs to make them displayed in really annoying
colours...

Close the pane if the process died due to a signal, not just if it exited
normally.

Remove a couple of unused arguments where possible, and add /* ARGSUSED */ to
the rest to reduce lint output.

Destroy panes immediately rather than checking them all every loop.

Free the pane bufferevent when the fd is closed (the signal could come before
the error callback).

Only need to chmod +x or -x the socket when a client is created, lost or
attached, rather than every event loop.

EVLOOP_ONCE takes care of the wakeup, so no need to call event_loopexit(NULL).

Now all timers are events, there is no longer any need to wake up every 50 ms -
only wake up when an event happens.

Move status timer check into the global once-per-second timer, this could maybe
be done better but one every second is better than once every 50 ms.

Don't reenlist the client imsg event every loop, instead have a small function
to it and call it after the event triggers or after a imsg is added.

Tell the client to exit on configuration file error.

Convert the window pane (pty master side) fd over to use a bufferevent.

The evbuffer API is very similar to the existing tmux buffer API so this was
remarkably painless. Not many possible ways to do it, I suppose.

Call event_init() before loading the config file, since potentially it could
set up events.

Switch jobs over to use a bufferevent.

Initial changes to move tmux to libevent.

This moves the client-side loops are pretty much fully over to event-based only
(tmux.c and client.c) but server-side (server.c and friends) treats libevent as
a sort of clever poll, waking up after every event to run various things.

Moving the server stuff over to bufferevents and timers and so on will come
later.

Change session and client activity and creation time members to have more
meaningful names.

Also, remove the code to try and update the session activity time for the
command client when a command message is received as is pointless because it
des not have a session.

Reorder slightly to tidy code.

Move the poll registration functions into the server-*.c files.

tabs are better; ok nicm

Clear signal flags /before/ taking action and continue afterwards to reduce
chance of dropping signals. Pointed out by deraadt@.

Split the server code handling clients, jobs and windows off into separate
files from server.c (merging server-msg.c into the client file) and rather than
iterating over each set after poll(), allow a callback to be specified when the
fd is added and just walk once over the returned pollfds calling each callback
where needed.

More to come, getting this in so it is tested.

When a session is unattached, reset its activity timer to prevent it locking
instantly when reattached.

Similarly add a tty_cursor_pane function to tidy up most of the calls.

_absolute is redundant, just use tty_region.

Cleanup: use two functions for region setting, one for absolute and one inside
pane.

Add a pipe-pane command to allow a pane to be piped to a shell command, for
example:

pipe-pane 'cat >~/out'

No arguments stops outputing and closes the pipe; the -o flag toggles a pipe
and on and off (useful for key bindings).

Suggested by espie@.

Switch run-shell over to queue the command in the background like #().

Collect status from dead jobs and don't invoke the callback until both
all input (the socket is closed) and status is available.

Clean up by introducing a wrapper struct for mouse clicks rather than passing
three u_chars around.

As a side-effect this fixes incorrectly rejecting high cursor positions
(because it was comparing them as signed char), reported by Tom Doherty.

Braek some bits out of server_fill_client() that aren't really related to
polling into their own function.

Put all jobs on a global all_jobs list and use that in server.c instead of
running through all the clients.

Rather than running status-left, status-right and window title #() with popen
immediately every redraw, queue them up and run them in the background,
starting each once every status-interval. The actual status line uses the
output from the last run.

This brings several advantages:

- tmux itself may be called from inside #() without causing the server to hang;
- likewise, sleep or similar doesn't cause the server to block;
- commands aren't run excessively often when redrawing;
- commands shared by status-left and status-right, or used multiple times, will
only be run once.

run-shell and if-shell still use system()/popen() but will be changed over to
use this too later.

New option, mouse-select-pane. If on, the mouse may be used to select the
current pane.

Suggested by sthen@ and also by someone else ages ago who I have forgotten.

Add "grouped sessions" which have independent name, options, current window and
so on but where the linked windows are synchronized (ie creating, killing
windows and so on are mirrored between the sessions). A grouped session may be
created by passing -t to new-session.

Had this around for a while, tested by a couple of people.

Support for individual session idle time locking. May be enabled by turning off
the lock-server option (it is on by default). When this is off, each session
locks when it has been idle for the lock-after-time setting. When on, the
entire server locks when ALL sessions have been idle for their individual
lock-after-time settings.

This replaces one global-only option (lock-after-time) with another
(lock-server), but the default behaviour is usually preferable so there don't
seem to be many alternatives.

Diff/idea largely from Thomas Adam, tweaked by me.

Instead of passing a struct pollfd ** around through various functions, build
them into a tree and then convert into a flat poll array before and after poll.

This adds a little code but should reduce annoying problems with ordering when
adding new things that also need to be polled.

If no target client is specified to commands which accept one, try to guess the
current client, in a similar manner to how sessions already work: if the
current session can be established and has only one client, use that; otherwise
use the most recently created client.

Don't allow locked or suspended clients to limit the size of active clients.

On SIGTERM, just abandon any suspended/locked clients and leave them to it,
otherwise the server will hang around (refusing new connections) until they
exit properly.

Remove the internal tmux locking and instead detach each client and run the
command specified by a new option "lock-command" (by default "lock -np") in
each client.

This means each terminal has to be unlocked individually but simplifies the
code and allows the system password to be used to unlock.

Note that the set-password command is gone, so it will need to be removed from
configuration files, and the -U command line flag has been removed.

This is the third protocol version change so again it is best to stop the tmux
server before upgrading.

Permit multiple prefix keys to be defined, separated by commas, for example:

set -g prefix ^a,^b

Any key in the list acts as the prefix. The send-prefix command always sends
the first key in the list.

Regularise some fatal messages.

New option, set-titles-string, to allow the window title to be specified (as
for status-left/right) if set-titles is on. Also only update the title when the
status line is being redrawn.

The default terminal size should be 80x24, not 80x25.

Nuke unused server_client_index function, pointed out by martynas@.

Doh, trim variables unused now.

Tidy some common code for destroying sessions into a new function.

Permit options such as status-bg to be configured using the entire 256 colour
palette by setting "colour0" to "colour255".

While the display-panes indicator is on screen, make the number keys select the
pane with that index.

Reference count clients and sessions rather than relying on a saved index for
cmd-choose-*.

Tiny cleanup.

ok nicm@

Only redraw all clients once when the backoff timer expires rather than every
second all the time.

Reported by Simon Nicolussi.

Tell the user when sleeping due to password backoff.

When shutting down the server, expect clients to be polite and exit when asked
with the right message.

Add a new display-panes command, with two options (display-panes-colour and
display-panes-time), which displays a visual indication of the number of each
pane.

Don't call tty_free unless the client is a terminal, otherwise tty_init hasn't
been called and it may end up doing close(0). From Kalle Olavi Niemitalo.

When using source-file, run the commands in the context of the source-file
command rather than with no context. This makes things like attach work from a
file.

Whoops, getting the comparison the right way round is usually recommended.

options_get_number() is relatively expensive and a check for dead panes happens
a lot more often than actually finding one, so instead of getting the option
for every check, get it for every dead window found.

Reset attributes as well as scroll region before poll(2) and add a big comment
explaining why.

Initialise log_fd to -1, prevents spurious disconnection of the client when it
ends up as fd 0 (likely if the server is started with "tmux start").

Also add some extra debugging messages to server.c.

Drop the no_stop argument to tty_close and tty_free in favour of a flag in the
tty struct.

Switch tmux to use imsg. This is the last major change to make the
client-server protocol more resilient and make the protocol versioning work
properly. In future, the only things requiring a protocol version bump will be
changes in the message structs, and (when both client and server have this
change) mixing different versions should nicely report an error message.

As a side effect this also makes the code tidier, fixes a problem with the way
errors reported during server startup were handled, and supports fd passing
(which will be used in future).

Looked over by eric@, thanks.

Please note that mixing a client with this change with an older server or vice
versa may cause tmux to crash or hang - tmux should be completely exited before
upgrading.

Reset the attributes after drawing all or part of the screen, and reset the
region before poll(2). This reduces (but does not eliminate) the chance of the
attributes not being normal if tmux is disconnected without warning (ssh ~.,
reboot from inside, etc).

If there is an error in the configuration file, don't just exit(1) as this can
cause the client to hang. Instead, send the error message, then mark the client
as bad and start a normal shutdown so the server exits once the error is
written.

This also allows some code duplicating daemon(3) to be trimmed and logging to
begin earlier.

Prompted by Theo noticing the behaviour on error wasn't documented.

Next step towards customisable mode keys: build each default table of keys into
a named tree on start and use that for lookups. Also add command to string
translation tables and modify list-keys to show the the mode key bindings (new
-t argument).

Permit commands to be bound to key presses without the prefix key first. The
new -n flag to bind-key and unbind-key sets or removes these bindings, and
list-key shows them in []s.

Make some functions which return unused values void (mostly found by lint) and
tweak a redundant expression in window_pane_set_mode.

Display the number of failed password attempts (if any) when the server is
locked. From Tom Doherty.

Improved layout code.

Each window now has a tree of layout cells associated with it. In this tree,
each node is either a horizontal or vertical cell containing a list of other
cells running from left-to-right or top-to-bottom, or a leaf cell which is
associated with a pane.

The major functional changes are:

- panes may now be split arbitrarily both horizontally (splitw -h, C-b %) and
vertically (splitw -v, C-b ");
- panes may be resized both horizontally and vertically (resizep -L/-R/-U/-D,
bound to C-b left/right/up/down and C-b M-left/right/up/down);
- layouts are now applied and then may be modified by resizing or splitting
panes, rather than being fixed and reapplied when the window is resized or
panes are added;
- manual-vertical layout is no longer necessary, and active-only layout is gone
(but may return in future);
- the main-pane layouts now reduce the size of the main pane to fit all panes
if possible.

Thanks to all who tested.

Add three new session options: visual-activity, visual-bell, visual-content. If
these are enabled (and the monitor-activity, bell-actio and monitor-content
options are configurated appropriately), when activity, a bell, or content is
detected, a message is shown.

Also tidy up the bell/activity/content code in server.c slightly and fix a
couple of errors.

Instead of faking up a status line in status_redraw, use the same code to
redraw it as to draw the entire screen, just skip all lines but the last.

This makes horizontal split redraw properly when the status line is off.

Creating a key binding which replaces itself (such as "bind x bind x lsw")
frees the command list bound to the key while it is still being executed,
leading to a use after free. To prevent this, create a dead keys list and defer
freeing replaced or removed key bindings until the main loop when the key
binding will have finished executing.

Found by Johan Friis when creating a key binding to reload his configuration
file.

If it exist, load a system-wide configuration file /etc/tmux.conf before any
user-specified one.

Rename the global options variables to be shorter and to make session options
clear. No functional change, getting this out of the way to make later options
changes easier.

After logging (if enabled) is switched to file, there is no reason to keep
stdin/stdout/stderr active, so dup them to /dev/null.

Remove some dead assignments, found by sthen with clang.

Change find-window and monitor-content to use fnmatch(3). For convenience and
compatibility, *s are implicitly added at the start and end of the pattern.

Also display the line number and the entire line in the results, and lose the
nasty section_string function and the now empty util.c file.

Initially from Tiago Cunha.

Make remain-on-exit work again when there is only one pane left, which was
broken sometime during the pane/layout changes. Reported/tested by Iain Morgan,
thanks.

Import tmux, a terminal multiplexor allowing (among other things) a single
terminal to be switched between several different windows and programs
displayed on one terminal be detached from one terminal and moved to another.

ok deraadt pirofti

Rewrite combined character handling to be more consistent and to support
newer Unicode combined characters (which we have to "know" are combined
since they are not width zero). GitHub issue 3600.

Add support for OSC 8 hyperlinks (a VTE extension now supported by other
terminals such as iTerm2). Originally written by me then extended and
completed by first Will Noble and later Jeff Chiang. GitHub issues 911,
2621, 2890, 3240.

Store time lines are scrolled into history and display in copy mode.

Add an ACL list for users connecting to the tmux socket. Users may be
forbidden from attaching, forced to attach read-only, or allowed to
attach read-write. A new command, server-access, configures the list.
tmux gets the user using getpeereid(3) of the client socket. Users must
still configure file system permissions manually. From Dallas Lyons and
others.

Report error if creating socket fails with -D.

Fix exit message if creating socket fails.

Fix warnings, from Jan Tache in GitHub issue 2692.

Tidy old jobs every hour instead of every 30 seconds.

Add a couple of helper functions, and flush imsgs on exit.

Fix some warnings, GitHub issue 2382.

Add a flag to make a client wait for an empty line before exiting in
control mode to avoid stray commands ending up in the shell.

Instead of sending all data to control mode clients as fast as possible,
add a limit of how much data will be sent to the client and try to use
it for panes with some degree of fairness. GitHub issue 2217, with
George Nachman.

xterm-keys has been on by default for five years and all other modern
terminals use these key sequences by default. Merge the code into the
main tty and input tree processing (converting the latter to use a tree
rather than a table at the same time) and make the option a no-op.

Add a -D flag to ask tmux not to daemonize, useful both for running a
debugger (lldb does not have follow-fork-mode) and for running with a
managed supervisor init system. GitHub issue 2190.

Change message log to be per server rather than per client and include
every command that is run.

Add 'e' key in buffer mode to open the buffer in an editor.

When the server socket is given by the user with -S, create it with
umask 177 instead of 117 because it may not be in a safe directory like
the default directory in /tmp. The user can chmod it more open after it
is created if they want.

Expand command formats in %if and move the config file loading later (to
when the first client has identified) so all the client formats are
available, fixes problems reported by Thomas Sattler.

Do not load the config file if the server is exiting because it failed
to start, otherwise commands like lsk which start the server again can
end up looping infinitely. Also make the first client exit
correctly. Problem reported by Wael M Nasreddine.

Replace the various identical error callbacks with a single one in cmd-queue.c.

Break new window and pane creation common code from various commands and
window.c into a separate file spawn.c.

Move job struct into job.c.

SESSION_UNATTACHED flag is no longer necessary now we have an attached
count instead.

session_groups can be static also.

Add a missing client-detached hook when the server shuts down, and do
not exit until jobs started from run-shell/if-shell have finished (add a
job flags member and a flag to indicate other jobs). GitHub issue 1245.

Add exit-empty option to exit server if no sessions (defaults to on).

Report better error from server when socket create fails, GitHub issue
1201.

Show exit status and time in the remain-on-exit pane text, mostly from
Timo Boettcher in GitHub issue 1103.

Because ignore SIGCHLD early, letting signal_del restore it doesn't work
correctly, so set it explicitly back to default (and the others for good
measure).

Block signals between forking and clearing signal handlers (or calling
event_reinit) - if the child gets a signal and fires the libevent signal
handler during this period it could write a signal into the parent's
signal pipe. GitHub issue 1001 from Aaron van Geffen.

Move signal code into proc.c.

Some extra logging to show why tmux might exit.

Do not close panes until process has exited and any outstanding data
has been written to the pipe-pane event if there is one. GitHub issue 991.

Support SIGUSR2 to stop and start logging for an existing server. Also
we currently only have two log levels so just use -v and -vv rather than
-v and -vvvv, and clarify the man page entry for -v.

Memory leaks, from David CARLIER.

Make the cmd_find_* functions more obvious when looking for a client,
rather than having it inside other functions. Should be no change to the
way targets are resolved just yet.

History needs to be loaded after config parsing is done - now that
commands are queued, that's in cfg_done not after start_cfg finishes.

If a #() command doesn't exit, use its most recent line of output (it
must be a full line). Don't let it redraw the status line more than once
a second.

Requested by someone about 10 years ago...

Instead of numbering session groups, give them a name which may be given
to -t instead of a target session. Also allow them to contain only one
session.

Fixed keys for choose mode, and remove the last mode keys bits.

Do not execute commands for a client until it has identified, fixes
problem reported by Frank Terbeck.

Notifys can go via the command queue instead of using their own queue.

Rewrite command queue handling. Each client still has a command queue,
but there is also now a global command queue. Instead of command queues
being dispatched on demand from wherever the command happens to be
added, they are now all dispatched from the top level server
loop. Command queues may now also include callbacks as well as commands,
and items may be inserted after the current command as well as at the end.

This all makes command queues significantly more predictable and easier
to use, and avoids the complex multiple nested command queues used by
source-file, if-shell and friends.

A mass rename of struct cmdq to a better name (cmdq_item probably) is
coming.

Drain notifys once at the end of the server loop instead of doing it
from the end of every command queue (which could be nested).