#!/bin/sh
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or (at
# your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see .
#
# ----------------------------------------------------------------------
##
## === gosher ===
##
## gosher is a simple Gopher server in a POSIX shell script:
##
## $ ./gosher [ []
##
## If PORT is not specified, the default is 70. If GOPHERDIR is not
## specified, "./" is assumed
##
##
## (c) 2018 Vincenzo 'KatolaZ' Nicosia
##
##
######################
##
## If the script is called with basename "gosher", launch the netcat
## server...
##
##
## NETCAT: the netcat command to use, and any additional option
##
### Original netcat
##NETCAT="nc.traditional"
##
### ncat (from nmap)
##NETCAT="ncat"
##
### Openbsd netcat
NETCAT="nc.openbsd"
##
## STYLE: The way in which netcat will talk to gosher_serve
##
### fork with "-c" (Does *not* work with OpenBSD netcat!!!!!)
#STYLE='fork'
##
### use named pipes (Does *not* work with original netcat!!!!!)
STYLE='pipe'
### prefix of the input FIFO
IPREFIX=/tmp/inf_
DEBUG=
#DEBUG=yes
[ -n "$DEBUG" ] && {
set -e
set -x
}
## function
cleanup(){
[ -n "$INF" ] && [ -p "$INF" ] && rm -f "${INF}"
exit 1
}
MYNAME=$(basename "$0")
MYDIR=$(dirname "$(realpath "$0")")
NETCAT=$(which "$NETCAT")
if [ -z "${MYNAME#gosher}" ]; then
## we are called as gosher -- launch the server
PORT=${1:-70}
GOPHERDIR=${2:-"./"}
[ ! -f "${NETCAT}" ] || [ ! -x "${NETCAT}" ] && {
echo "Wrong NETCAT -- Exiting" >&2
exit 2
}
if [ -f "${MYDIR}/gosher_serve" ] || [ -h "${MYDIR}/gosher_serve" ]; then
GOSHER_SERVE="${MYDIR}/gosher_serve"
trap cleanup 0 HUP INT TRAP TERM QUIT
INF="${IPREFIX}$$"
[ "$STYLE" = "pipe" ] && {
mkfifo -m 600 "$INF"
# shellcheck disable=SC2050
while [ 1 -eq 1 ]; do
# shellcheck disable=SC2094
${GOSHER_SERVE} "${GOPHERDIR}" <"$INF" | ${NETCAT} -vvvvv -l -p "${PORT}" >"$INF"
done
rm -f $INF
exit 0
}
[ "$STYLE" = 'fork' ] && {
# shellcheck disable=SC2050
while [ 1 -eq 1 ]; do
${NETCAT} -vv -l -p "$PORT" -c "${GOSHER_SERVE} ${GOPHERDIR}"
done
exit 0
}
echo "Wrong STYLE specified -- Exiting" >&2
exit 2
else
echo "Cannot find gosher_serve -- Exiting">&2
exit 3
fi
fi
######################
##
## ...otherwise, serve a request
##
## function
invalid_selector(){
sel="$1"
echo "3Error: Invalid selector: \"$sel\""
# shellcheck disable=SC1117
printf ".\r\n"
exec 1>&-
exec 2>&-
exit 1
}
## function
serve_selector(){
sel="$1"
cat "${sel}"
echo "$0: selector $sel served -- exiting " >&2
exec 1>&-
exec 2>&-
exit 0
}
### transform a .gph file into a gophermap
## function
serve_index(){
IDX=$1
IFS='
'
while read -r line; do
rline=$(echo "$line" | sed -r -e 's/\r//g')
case "$rline" in
'['*)
echo "$rline" | sed -r -e 's/\[//g;s/\]//g;s/\|/\t/g;s/\t//;s/$/\r/g'
;;
t*)
echo "$rline" | cut -c 2-
;;
*)
echo "$line"
esac
done < "$IDX"
# shellcheck disable=SC1117
printf ".\r\n"
exec 1>&-
exec 2>&-
exit 0
}
### Serve an HTML URL through a redirect page
## function
serve_redirect(){
url=$1
cat<< EOF
gopher redirect
Click to be redirected to: $url
EOF
exec 1>&-
exec 2>&-
exit 0
}
GOPHERDIR=${1:-"./"}
read -r selector
selector=$(echo "$selector" | sed -r 's:\$.*::g;s:\r::g' )
[ -n "$DEBUG" ] && {
echo "iGOPHERDIR: ${GOPHERDIR}"
echo "iselector: \"${selector}\""
}
case $selector in
URL:*)
url=$(echo "$selector" | cut -d ":" -f 2-)
serve_redirect "$url"
;;
/?*|"")
RP1=$(realpath "${GOPHERDIR}"/"${selector}" || "")
# shellcheck disable=SC2181
[ $? -eq 0 ] || invalid_selector "$selector"
RP2=$(realpath "${GOPHERDIR}")"${selector}"
# shellcheck disable=SC2181
[ $? -eq 0 ] || invalid_selector "$selector"
[ -n "$DEBUG" ] && {
echo "iRP1: ${RP1}"
echo "iRP2: ${RP2}"
}
if [ "${RP1}" = "${RP2}" ]; then
if [ -f "${RP1}" ]; then
if [ -n "$(echo "${RP1}" | sed -n '/\.gph$/p')" ]; then
serve_index "${RP1}"
else
serve_selector "${RP1}"
fi
elif [ -d "${RP1}" ]; then
[ -f "${RP1}/gophermap" ] && serve_selector "${RP1}/gophermap"
[ -f "${RP1}/index.gph" ] && serve_index "${RP1}/index.gph"
fi
fi
invalid_selector "$selector"
;;
*)
[ -f "${GOPHERDIR}/gophermap" ] && serve_selector "${GOPHERDIR}/gophermap"
[ -f "${GOPHERDIR}/index.gph" ] && serve_index "${GOPHERDIR}/index.gph"
echo "got invalid selector: \"$selector\"" >&2
invalid_selector "/"
;;
esac