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|
#!/bin/bash
BASH_ARGV0=twopane.bash
echo -n "$0" >/proc/$BASHPID/comm
set -e
set -f
set -o pipefail
shopt -s lastpipe
PS4='+ \t$LINENO\t '
. read_chars.bash
. finally.bash
kill_tty_forward()
{
read pid < "$TWOPANE"/tty_forward.pid
/bin/kill "${1:-'-INT'}" -- -$pid 2>/dev/null
}
BOT_SIZE=8
BOT_TITLE=input
DO_RESTART=
DO_START=
DO_START=y
DO_RESTART=y
if [ $# = 0 ]
then
TOP_CMD="$SHELL -i"
if [ "$DO_RESTART" ]
then
SIG=INT
BOT_CMD=PROMPT_COMMAND=prompt_command
TOP_EXIT=restart
elif [ "$DO_START" ]
then
BOT_CMD=start
TOP_EXIT=quit
else
BOT_CMD=PROMPT_COMMAND=prompt_command
TOP_EXIT=prompt
fi
elif [ "$TWOPANE" -a "$*" = detach ]
then
kill_tty_forward -TSTP
exit
elif [ "$TWOPANE" -a "$*" = focus ]
then
screen -X focus
exit
elif [ "$TWOPANE" -a "$*" = quit ]
then
screen -X quit
exit
else
TOP_CMD=$*
BOT_CMD=start
TOP_EXIT=quit
fi
TOP_TITLE="Command: $TOP_CMD"
TWOPANE=$(mktemp -d)
export TWOPANE TOP_CMD BOT_CMD TOP_TITLE BOT_TITLE BOT_SIZE
trap 'rm -r "$TWOPANE"' EXIT
# STY=$(systemd-escape -p "$TWOPANE")
systemd_escape_path()
{
declare -n path="$1" result="$2"
result=$(realpath "$path")
result=${result//-/--}
result=${result//\//-}
}
systemd_escape_path TWOPANE STY
STY=$0.$$.$STY
save_file()
{
cat > "$TWOPANE"/"${1:?$0: Error: filename cannot be empty string}"
}
save_screenrc()
{
save_file screenrc"${1:+.$1}"
}
save_screenrc <<'.'
# Disable keybindings.
unbindall
escape \0\0
# Disable messages. This is needed for screen -X/-Q to work reasonably.
msgwait 0
msgminwait 0
bellmsg ^G
vbell off
# Try to disable blocking the terminal on ^S.
# Doesn't seem to work here.
# More is needed. Xterm?
nonblock on
# Enable mouse focus
defmousetrack on
mousetrack on
caption string '%t'
layout new
split
focus bottom
resize $BOT_SIZE
screen -ln -t "$BOT_TITLE" 0 bash --noprofile --rcfile "$TWOPANE"/bashrc -i
layout save 0
.
with_screen_pane()
{
(( $# > 1 )) || return
declare -i PANE="$1" LOCK
(( PANE > 0 )) || return
(
flock $LOCK
"$2" "$1" "${@:3}"
) {LOCK}>"$TWOPANE"/pane$PANE
}
check_screen_pane()
{
(( PANE > 0 )) || return
screen -p "$PANE" -Q info >/dev/null
}
kill_screen_pane()
{
(( PANE > 0 )) || return
while check_screen_pane "$PANE"
do
screen -p "$PANE" -X kill
done
}
start_screen_pane()
{
(( PANE > 0 )) || return
if check_screen_pane "$PANE"
then
i "pane already running: $PANE"
return
else
i "starting pane: $PANE"
fi
shift
if [ $# = 0 ]
then
set -f
set -- ${TOP_CMD:-bash -i}
fi
TOP_TITLE="Command: ${*@Q}"
screen -X focus top
screen -X screen -ln -t "$TOP_TITLE" 1 "$@"
start_screen_pane_subprocess
}
start_screen_pane_subprocess()
{
(( PANE > 0 )) || return
subproc_command=(
exec -a top-pane-tty-forward
socat
UNIX-LISTEN:"$TWOPANE"/socket
STDIN,cfmakeraw,opost=1,onlcr=1!!STDOUT
)
screen -p "$PANE" -X exec .!. bash -c "${subproc_command[*]}"
}
restart_pane()
{
(( PANE > 0 )) || return
kill_screen_pane
start_screen_pane "$@"
}
restart_top_pane()
{
with_screen_pane 1 restart_pane "$@"
}
# connect_coproc() -- start a coprocess and connect it to copied file
# descriptors named {NAME}_IN and {NAME}_OUT where {NAME} is the
# supplied first argument or default "COPROC". {NAME} is the name of
# the created bash coprocess.
# The copied file descriptors (unlike the original coprocess
# file descriptors, in ${NAME[0]} and ${NAME[1]}) can be
# passed to external processes (e.g.: socat(1) instances) and
# used in subshells.
# The created coprocess is silently disowned from job control before
# bash can make noise about it.
connect_coproc()
{
[ $# -gt 0 ] || set -- COPROC
declare -n coproc="$1"
shift
[ $# -gt 0 ] || set -- "${!coproc}"
declare -n std0="${!coproc}_IN"
declare -n std1="${!coproc}_OUT"
declare -n std2="${!coproc}_ERR"
declare -n pid="${!coproc}_PID"
if ! [ "$pid" ]
then
i "coproc starting: ${!coproc}"
{
coproc "${!coproc}" \
{
"$@"
} 2>&$std2 {std2}>&-
unset std2
disown "%coproc ${!coproc} "
} {std2}>&2 2>/dev/null
else
i "coproc already running: ${!coproc}"
fi
{
exec {std0}<&0 {std1}>&1
} <&${coproc[0]} >&${coproc[1]}
}
disconnect_coproc()
{
[ $# -gt 0 ] || set -- COPROC
declare -n coproc="$1"
declare -n std0="${!coproc}_IN"
declare -n std1="${!coproc}_OUT"
declare -n pid="${!coproc}_PID"
if [ "$std0" -o "$std1" ]
then
exec {std0}<&- {std1}>&-
fi
if [ "$pid" ]
then
kill "$pid" 2>/dev/null
wait -f "$pid" 2>/dev/null
fi
unset coproc std0 std1 pid
}
connect()
{
if ! [ "$TOP_PANE_PID" ]
then
disconnect_sink ECHOSEND
connect_coproc TOP_PANE
fi
connect_sink ECHOSEND echo_sender
}
disconnect()
{
: "${TOP_PANE_IN@A} ${TOP_PANE_OUT@A} ${TOP_PANE_PID@A} ${TOP_PANE[@]@A}"
disconnect_coproc TOP_PANE
: "${ECHOSEND@A} ${ECHOSEND_PID@A}"
disconnect_sink ECHOSEND
}
sendc()
{
[ "${TOP_PANE[0]}" ] || connect
printf '%s' "$*" >&${TOP_PANE_OUT?Internal error}
}
send()
{
[ "${TOP_PANE[0]}" ] || connect
printf '%s\n' "$*" >&${TOP_PANE_OUT?Internal error}
}
tty_forward()
{
printf '%d\n' "$BASHPID" > "$TWOPANE"/tty_forward.pid
trap 'kill -INT $$' INT
read-tty
}
TOP_PANE()
{
(exec -a bottom-pane-tty-forward socat - UNIX-CONNECT:"$TWOPANE"/socket,forever)
case "$TOP_EXIT" in
restart )
x kill_tty_forward -STOP
x kill -INT $$
;;
quit )
quit
;;
prompt | * )
x kill_tty_forward -STOP
focus bottom
;;
esac
}
connect_sink()
{
(( $# > 0 )) || set -- SINK
declare -n fd="$1"
declare -n pid="${!fd}_PID"
if [ "$pid" ]
then
i "sink already running: ${!fd}"
return
fi
i "sink starting: ${!fd}"
exec {fd}> >("${@:2}")
pid=$!
}
disconnect_sink()
{
(( $# > 0 )) || set -- SINK
declare -n fd="$1"
[ "$fd" ] || return
declare -n pid="${!fd}_PID"
i "sink stopping: ${!fd}"
exec {fd}>&-
kill $pid 2>/dev/null
unset fd pid
}
quiet_bg()
{
local STDERR
{
eval "$(printf '%q ' "$@") & 2>&\$STDERR {STDERR}>&-"
} {STDERR}>&2 2>/dev/null
}
# echo_sender() reads from two inputs and writes to two outputs.
#
# Read from both:
# read from stdin
# read from $TOP_PANE_IN
# Write to both:
# write to stdout
# write to $TOP_PANE_OUT
# I.e.:
# read from /dev/tty
# read from the socat-coproc-forwarded /dev/tty in the top pane.
# write to /dev/tty
# write to the socat-coproc-forwarded /dev/tty in the top pane.
echo_sender()
{
(exec -a echo_sender socat - fd:${TOP_PANE_IN?$0: Internal error}!!-) |
tee >(write-tty) >&${TOP_PANE_OUT?$0: Internal error}
}
restart_tty_forward()
{
detach
with_screen_pane 1 start_screen_pane "$@"
focus bottom
connect
i 'starting tty_forward'
quiet_bg tty_forward >&$ECHOSEND
echo $! > "$TWOPANE"/tty_forward.pid
}
attach()
{
if ! jobs %tty_forward &>/dev/null
then
restart_tty_forward "$@"
fi
focus top
{ %tty_forward; } &>/dev/null
focus bottom
}
detach()
{
{
kill -INT %tty_forward
disown %tty_forward
} &>/dev/null
}
restart() { attach "$@"; }
start() { attach "$@"; }
foreground() { attach "$@"; }
twopane() { attach "$@"; }
forward() { attach "$@"; }
quit()
{
screen -X quit
}
focus()
{
screen -X focus "$@"
}
resize()
{
screen -X resize "$@"
}
SIGUSR1()
{
i "SIGUSR1: ${BASH_COMMAND@A}"
}
SIGCHLD()
{
i "SIGCHILD: ${BASH_COMMAND@A}"
}
killpgrp()
{
(( $# == 2 )) && /bin/kill "$1" -- -"$2"
}
prompt_command()
{
[ "$TOP_EXIT" = 'restart' ] || return 0
if [ "$SIG" = INT ]
then
finally 'unset SIG; start' detach
return
fi
local job
if ! { job=$(jobs %tty_forward 2>/dev/null) && [ "$job" ]; }
then
finally 'start' :
return
fi
read _ jobstatus _ <<< "${job?${LINENO@A}}"
case "${jobstatus?${LINENO@A}}" in
Running )
jobs -x finally 'attach' killpgrp -CONT %tty_forward
;;
Interrupt )
finally 'start' :
;;
Stopped )
;;
esac
}
SIGINT()
{
i INT "${BASH_COMMAND@A}"
kill $TOP_PANE_PID $ECHOSEND_PID 2>/dev/null
SIG=INT
PROMPT_COMMAND=prompt_command
}
our_bashrc_main()
{
BASH_ARGV0=twopane
echo -n "$0" >/proc/$BASHPID/comm
set -m
set -f
set -o pipefail
trap 'SIGUSR1' USR1
# trap 'SIGCHLD' CHLD
trap 'SIGINT' INT
trap '! [ "$DEBUG" ] || read -p "Exit> "; quit' EXIT
export PS1="$BOT_TITLE\\\$ "
}
save_file bashrc <<.
${TOP_CMD@A}
${BOT_CMD@A}
${TOP_TITLE@A}
${BOT_TITLE@A}
${TOP_EXIT@A}
$(declare -f)
our_bashrc_main
$BOT_CMD
.
main()
{
screen -c "$TWOPANE"/screenrc -m -S "$STY" -ln
}
main "$@"
|