initial commit

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Michael Krayer 2021-03-18 10:58:17 +01:00
commit 498481c491
1 changed files with 283 additions and 0 deletions

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session Executable file
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#!/bin/bash
shopt -s nullglob
## Setup configuration
CONFIG_FILE="$HOME/.sessionrc"
typeset -A config
# Set defaults
config=(
[socket_dir]="/tmp/"
[socket_base]="session-$UID"
[shell]="/bin/bash"
[redraw]="winch"
)
# Source from configuration file if available
if [ -f "$CONFIG_FILE" ]; then
while read line
do
if echo $line | grep -F = &>/dev/null
then
varname=$(echo "$line" | cut -d '=' -f 1)
config[$varname]=$(echo "$line" | cut -d '=' -f 2- | envsubst)
fi
done < $CONFIG_FILE
fi
## Set some variables
SOCKET_PREFIX="${config[socket_dir]}/${config[socket_base]}-"
SOCKET_SUFFIX=".socket"
# Exit codes
EXIT_SUCCESS=0
EXIT_INVALID_MODE=1
EXIT_SESSION_EXISTS=2
EXIT_SESSION_NOT_EXIST=3
EXIT_ALREADY_IN_SESSION=4
EXIT_INVALID_CONFIG=5
EXIT_CONFIG_EXISTS=6
EXIT_INVALID_CHOICE=7
## Functions
print_help() {
echo >&2 "Usage: $(basename $0) mode [args]"
echo >&2 "Manage detachable shell sessions using 'dtach'."
echo >&2 "Available modes: "
echo >&2 " attach | att | a attach to an existing session"
echo >&2 " new | | n create a new session"
echo >&2 " terminate | term | t terminate an existing session (SIGTERM)"
echo >&2 " kill | | k send SIGKILL to an existing session"
echo >&2 " list | ls | l list all available sessions"
echo >&2 " info | | i print information on a session"
echo >&2 " help | | h display this help message"
echo >&2 ""
echo >&2 "$(basename $0) attach [name]"
echo >&2 " Attach to specified session. If no session name is provided, an interactive"
echo >&2 " selection menu is provided. Use <Ctrl-\\> to detach."
echo >&2 ""
echo >&2 "$(basename $0) new [name]"
echo >&2 " Create a new session. If no session name is provided, a generic name will"
echo >&2 " be generated. Use <Ctrl-\\> to detach."
echo >&2 ""
echo >&2 "$(basename $0) terminate [name]"
echo >&2 " Terminate a specified session. If no session name is provided, all sessions"
echo >&2 " will be terminated upon confirmation."
echo >&2 ""
echo >&2 "$(basename $0) kill [name]"
echo >&2 " Same as 'terminate' but SIGKILL is sent to the shell instead of SIGTERM."
echo >&2 ""
echo >&2 "$(basename $0) list"
echo >&2 " List all available sessions."
echo >&2 ""
echo >&2 "$(basename $0) info [name]"
echo >&2 " Print information on a specified session. If no session name is provided,"
echo >&2 " information on all sessions will be printed. The output contains the session"
echo >&2 " name, the timestamp of creation and the path of its socket."
echo >&2 ""
echo >&2 "$(basename $0) help"
echo >&2 " Print this help message."
echo >&2 ""
echo >&2 "$(basename $0) is configured using the file '$CONFIG_FILE', which, if"
echo >&2 "non-existent, can be initialized with '$(basename $0) config generate'."
}
get_available_sessions() {
local socket_paths=(${SOCKET_PREFIX}*${SOCKET_SUFFIX})
local socket_names=()
for spath in ${socket_paths[@]}; do
sname=${spath##${SOCKET_PREFIX}}
sname=${sname%%${SOCKET_SUFFIX}}
socket_names+=("${sname}")
done
echo ${socket_names[@]}
}
get_session_path() {
echo "${SOCKET_PREFIX}${1}${SOCKET_SUFFIX}"
}
is_existing_session_path() {
if [ -S $1 ]; then
true
else
false
fi
}
is_existing_session_name() {
is_existing_session_path $(get_session_path $1)
}
get_new_session_name() {
local ii=1
while is_existing_session_name $ii; do
ii=$((ii+1))
done
echo $ii
}
exit_if_in_session() {
if [ ! -z $DTACH_SOCKET_PATH ]; then
echo >&2 "Cannot attach to a session from within a session."
exit $EXIT_ALREADY_IN_SESSION
fi
}
exit_if_existing_session() {
if ! is_existing_session_name $session_name; then
echo >&2 "Session '$session_name' does not exist."
exit $EXIT_SESSION_NOT_EXIST
fi
}
exit_if_nonexisting_session() {
if ! is_existing_session_name $session_name; then
echo >&2 "Session '$session_name' does not exist."
exit $EXIT_SESSION_NOT_EXIST
fi
}
print_session_info() {
local session_name=$1
local session_path=$(get_session_path $session_name)
local session_time=$(date -r $session_path "+%Y-%m-%d %H:%M:%S")
printf "%-24s %-20s %s\n" "$session_name" "$session_time" "$session_path"
}
## Parse first argument (= mode argument)
if [[ "$#" -lt 1 ]]; then
print_help
exit $EXIT_INVALID_MODE
fi
mode=$1
shift
## Now enter mode specific code
case $mode in
"attach"|"att"|"a")
exit_if_in_session
# If no session name specified: select interactively
if [ -z "$1" ]; then
sessions_avail=($(get_available_sessions))
if [ ${#sessions_avail[@]} -eq 0 ]; then
exit $EXIT_SUCCESS
fi
echo >&2 "Select a session (q to quit)"
select session_name in ${sessions_avail[@]}
do
if [ -z "$session_name" ]; then
exit $EXIT_SUCCESS
fi
exit_if_nonexisting_session $session_name
break
done
else
session_name=$1
exit_if_nonexisting_session $session_name
fi
session_path=$(get_session_path $session_name)
CMD="dtach -a $session_path -r ${config[redraw]}"
exec $CMD
;;
"new"|"n")
exit_if_in_session
#PROMPT_COMMAND="echo -ne \"\033]0;$1 (on $HOSTNAME)\007\""
# PS1="\[\e]0;My Titlito\a\]>>"
# If no session name specified: generate a generic one
if [ -z "$1" ]; then
session_name=$(get_new_session_name)
else
session_name=$1
exit_if_existing_session $session_name
fi
session_path=$(get_session_path $session_name)
CMD="env DTACH_SOCKET_PATH=$session_path DTACH_SESSION_NAME=$session_name "
CMD+="dtach -c $session_path -r ${config[redraw]} ${config[shell]}"
echo $CMD
exec $CMD
;;
"terminate"|"term"|"t"|"kill"|"k")
# Check if we are in terminate/kill mode
if [[ ${mode::1} == "k" ]]; then
SIGNAL="-9" # SIGKILL
CLEANUP=1 # requires manual cleanup
else
SIGNAL="-15" # SIGTERM
CLEANUP=0
fi
# If no session name specified: terminate all sessions
if [ -z "$1" ]; then
read -p "Terminate all sessions? [y/N] " -n 1 -r
printf "\n"
case $REPLY in
"y"|"Y")
session_name=($(get_available_sessions))
;;
*)
echo "no"
;;
esac
else
session_name=$1
exit_if_nonexisting_session $session_name
fi
for sname in ${session_name[@]}; do
spath=$(get_session_path $sname)
PID=$(fuser $spath 2> /dev/null)
CMD="kill $SIGNAL $PID"
exec $CMD
if [[ "$CLEANUP" -eq 1 ]]; then
CMD="rm $spath"
exec $CMD
fi
done
exit $EXIT_SUCCESS
;;
"list"|"ls"|"l")
sessions_avail=($(get_available_sessions))
for sname in ${sessions_avail[@]}; do
printf "$sname"
if [[ "$sname" == "$DTACH_SESSION_NAME" ]]; then
printf "*"
fi
printf "\n"
done
exit $EXIT_SUCCESS
;;
"info"|"i")
# If no session name specified: info for all sessions
if [ -z "$1" ]; then
session_name=($(get_available_sessions))
else
session_name=$1
exit_if_nonexisting_session $session_name
fi
for sname in ${session_name[@]}; do
print_session_info $sname
done
exit $EXIT_SUCCESS
;;
"help"|"h")
print_help
exit $EXIT_SUCCESS
;;
"config")
if [[ "$1" != "generate" ]]; then
echo >&2 "Use '$(basename $0) config generate' to generate default configuration file."
exit $EXIT_INVALID_CONFIG
fi
if [ -f "$CONFIG_FILE" ]; then
echo >&2 "Configuration file '$CONFIG_FILE' already exists. Please remove it first."
exit $EXIT_CONFIG_EXISTS
fi
printf "" > $CONFIG_FILE
for key in ${!config[@]}; do
echo "${key}=${config[$key]}" >> $CONFIG_FILE
done
exit $EXIT_SUCCESS
;;
*)
echo >&2 "Invalid mode: ${mode}"
print_help
exit $EXIT_INVALID_MODE
;;
esac