#!/usr/bin/bash
# This default script is kept in /usr/sbin, and gets invoked
# by snget/sngetd for ALL servers.  If you want a special version for
# just one particular server (for example if a username/password is
# required), install an edited copy in that servers directory.
#
# We are invoked when snget/sngetd opens a connection to a
# server.  Our purpose is to read the server greeting and log in if
# required, and exit successfully if all is well.  We must leave the
# NNTP conversation is a consistent state.
#
# When that is done, we take the opportunity (since we now have the
# NNTP conversation all to ourselves) to upload any articles meant for
# this server and do some other housekeeping.
#
# Invocation environment:
# Descriptors 6 and 7 open to read and write NNTP, respectively.
# Current directory is the appropriate server directory (one of
# /var/spool/news/.outgoing/*/).
# If the server times out, we will be sent SIGALRM from
# snget/sngetd.
# These variables will be set:
# SERVER: name of the server we are talking to
# PORT: port number of same
# TIMEOUT: number of seconds of server inactivity before we are
# sent SIGALRM

ME=`basename $0`
log () { echo "$ME:$SERVER:$@" >&2; }
fail () { log "$@"; exit 1; }
CODE=
SAID=
nntp () { [ "x$@" = x ] || echo "$@
" >&7; read -r CODE SAID <&6 || exit 1; }

#
# Logging in and authentication.
#

authenticate () {
  nntp "AUTHINFO USER $1"
  if [ x$CODE != x281 ]; then
    [ x$CODE = x381 ] && nntp "AUTHINFO PASS `cat password`"
    [ x$CODE != x281 ] && fail "$SERVER refused us: $CODE $SAID"
  fi
}

username=
[ -f username ] && username=`cat username`
read -r CODE SAID <&6 || fail "Can't read server greeting"
case "$CODE" in
200|201)
  [ "x$username" != x ] && authenticate "$username"
  ;;
480)
  [ "x$username" = x ] && fail "Don't have a user name to log in with"
  authenticate "$username"
  ;;
*) fail "$SERVER bad greeting:$CODE $SAID"
  ;;
esac

#
# Some INN's want this.  Jim Hague was here.
#
nntp "MODE READER"

#
# Our job is done, we have successfully logged in, so regardless of
# what happens next we must exit 0.  Note: Caller does not care if
# we can successfully upload our articles, that is our responsibility.
#

end () { log "$@" >&2; exit 0; }
on_exit () { [ -e $tmp ] && rm -f $tmp; [ "x$lockf_proc" != x ] && kill $lockf_proc; }

trap on_exit 0

# Lock the server directory to serialise processing.
exec 3>.lock || end "Unable to open/create .lock"
read lockf_proc < <(exec snlockf 3>&3)
[ "x$lockf_proc" != x ] || exit 0

#
# Upload outgoing articles.
#

tmp=+HELLO.$$
rmcr () { sed -e 's/
//' -e '/^\.$/d' >$tmp || end "Can't run sed"; }

posts="`echo '$'*`"; [ "x$posts" = 'x$*' ] && posts=
for art in $posts; do
  nntp "POST"
  if [ "x$CODE" = x340 ]; then
    # Remove unnecessary headers.
    # Also remove the terminating dot if any (so we can replace it).
    sed '1,/^
$/{
/^[sS][eE][nN][dD][eE][rR] *:/d
/^[nN][nN][tT][pP]-[pP][oO][sS][tT][iI][nN][gG]-[hH][oO][sS][tT] *:/d
/^[bB][yY][tT][eE][sS] *:/d
/^[lL][iI][nN][eE][sS] *:/d
}
/^\.
$/d' $art >&7
    nntp "."
  fi
  if [ "x$CODE" != x240 ]; then
    rmcr <$art;
    # XXX Problem with LOGNAME if snget started by pppd
    mail -s "Posting failed ($CODE $SAID)" ${NEWSMASTER:-${LOGNAME:-newsmaster}} <$tmp ||
      end "Can't run mail"
  fi
  rm -f $art
done

#
# Service any requests.  Add your own stuff here, but remember:
# 1. Don't touch descriptor 3, because that is your lock.  Otherwise
#    you can do pretty much anything.
# 2. You should exit with success, regardless of what went wrong.
# 3. Use todot() or nntp() or similar to read from the network.
#    I know it's slow but if you use an external program to read
#    it could drop bytes, and the alarm trap won't kick in.
#

todot () { while read -r b; do [ "$b" = ".
" ] && break; echo "$b"; done <&6; }
inform () { todot | rmcr; [ -s $tmp ] && sh -c "$*" <$tmp; }
update () { date '+%y%m%d %H%M%S' >.t && mv .t .last-list && rm -f $1; }
cmd= ; getcmd () { [ -f $1 ] && cmd="`head -1 $1`" && [ "x$cmd" != x ]; }

if getcmd request-list; then
  nntp "LIST NEWSGROUPS"
  [ x$CODE != x215 ] && nntp "LIST"
  [ x$CODE != x215 ] && end "Can't request list:$CODE $SAID"
  inform "$cmd" || end "Unable to forward results"
  update request-list
elif getcmd request-newgroups; then
  date=`cat .last-list 2>/dev/null`
  nntp "NEWGROUPS ${date:-990101 000000}"
  [ x$CODE != x231 ] && end "Can't request newgroups:$CODE $SAID"
  inform "$cmd" || { [ -s $tmp ] && end "Unable to forward results"; }
  update request-newgroups
fi

: script done