# -*- mode:sh -*-
# Little common functions

# push a mirror attached to us.
# Arguments (using an array named SIGNAL_OPTS):
#
# $MIRROR      - Name for the mirror, also basename for the logfile
# $HOSTNAME    - Hostname to push to
# $USERNAME    - Username there
# $SSHPROTO    - Protocol version, either 1 or 2.
# $SSHKEY      - the ssh private key file to use for this push
# $SSHOPTS     - any other option ssh accepts, passed blindly, be careful
# $PUSHLOCKOWN - own lockfile name to touch after stage1 in pushtype=staged
# $PUSHTYPE    - what kind of push should be done?
#                all    - normal, just push once with ssh backgrounded and finish
#                staged - staged. first push stage1, then wait for $PUSHLOCKs to appear,
#                         then push stage2
# $PUSHARCHIVE - what archive to sync? (Multiple mirrors behind one ssh key!)
# $PUSHCB      - do we want a callback?
# $PUSHKIND    - whats going on? are we doing mhop push or already stage2?
# $FROMFTPSYNC - set to true if we run from within ftpsync.
#
# This function assumes that the variable LOG is set to a directory where
# logfiles can be written to.
# Additionally $PUSHLOCKS has to be defined as a set of space delimited strings
# (list of "lock"files) to wait for if you want pushtype=staged
#
# Pushes might be done in background (for type all).
signal () {
    ARGS="SIGNAL_OPTS[*]"
    local ${!ARGS}

    MIRROR=${MIRROR:-""}
    HOSTNAME=${HOSTNAME:-""}
    USERNAME=${USERNAME:-""}
    SSHPROTO=${SSHPROTO:-""}
    SSHKEY=${SSHKEY:-""}
    SSHOPTS=${SSHOPTS:-""}
    PUSHLOCKOWN=${PUSHLOCKOWN:-""}
    PUSHTYPE=${PUSHTYPE:-"all"}
    PUSHARCHIVE=${PUSHARCHIVE:-""}
    PUSHCB=${PUSHCB:-""}
    PUSHKIND=${PUSHKIND:-"all"}
    FROMFTPSYNC=${FROMFTPSYNC:-"false"}

    # And now get # back to space...
    SSHOPTS=${SSHOPTS/\#/ }

    # Defaults we always want, no matter what
    SSH_OPTIONS="-o user=${USERNAME} -o BatchMode=yes -o ServerAliveInterval=45 -o ConnectTimeout=45 -o PasswordAuthentication=no"

    # If there are userdefined ssh options, add them.
    if [ -n "${SSH_OPTS}" ]; then
        SSH_OPTIONS="${SSH_OPTIONS} ${SSH_OPTS}"
    fi

    # Does this machine need a special key?
    if [ -n "${SSHKEY}" ]; then
        SSH_OPTIONS="${SSH_OPTIONS} -i ${SSHKEY}"
    fi

    # Does this machine have an extra own set of ssh options?
    if [ -n "${SSHOPTS}" ]; then
        SSH_OPTIONS="${SSH_OPTIONS} ${SSHOPTS}"
    fi

    # Set the protocol version
    if [ ${SSHPROTO} -ne 1 ] && [ ${SSHPROTO} -ne 2 ] && [ ${SSHPROTO} -ne 99 ]; then
        # Idiots, we only want 1 or 2. Cant decide? Lets force 2.
        SSHPROTO=2
    fi
    if [ -n "${SSHPROTO}" ] && [ ${SSHPROTO} -ne 99 ]; then
        SSH_OPTIONS="${SSH_OPTIONS} -${SSHPROTO}"
    fi

    date -u >> "${LOGDIR}/${MIRROR}.log"

    PUSHARGS=""
    # PUSHARCHIVE empty or not, we always add the sync:archive: command to transfer.
    # Otherwise, if nothing else is added, ssh -f would not work ("no command to execute")
    # But ftpsync does treat "sync:archive:" as the main archive, so this works nicely.
    PUSHARGS="${PUSHARGS} sync:archive:${PUSHARCHIVE}"

    # We have a callback wish, tell downstreams
    if [ -n "${PUSHCB}" ]; then
        PUSHARGS="${PUSHARGS} sync:callback"
    fi
    # If we are running an mhop push AND our downstream is one to receive it, tell it.
    if [ "xmhopx" = "x${PUSHKIND}x" ] && [ "xmhopx" = "x${PUSHTYPE}x" ]; then
        PUSHARGS="${PUSHARGS} sync:mhop"
    fi

    if [ "xallx" = "x${PUSHTYPE}x" ]; then
        # Default normal "fire and forget" push. We background that, we do not care about the mirrors doings
        echo "Sending normal push" >> "${LOGDIR}/${MIRROR}.log"
        PUSHARGS1="sync:all"
        ssh -f $SSH_OPTIONS "${HOSTNAME}" "${PUSHARGS} ${PUSHARGS1}" >>"${LOGDIR}/${MIRROR}.log"
    elif [ "xstagedx" = "x${PUSHTYPE}x" ] || [ "xmhopx" = "x${PUSHTYPE}x" ]; then
        # Want a staged push. Fine, lets do that. Not backgrounded. We care about the mirrors doings.
        echo "Sending staged push" >> "${LOGDIR}/${MIRROR}.log"

        # Only send stage1 if we havent already send it. When called with stage2, we already did.
        if [ "xstage2x" != "x${PUSHKIND}x" ]; then
            # Step1: Do a push to only sync stage1, do not background
            PUSHARGS1="sync:stage1"
            ssh $SSH_OPTIONS "${HOSTNAME}" "${PUSHARGS} ${PUSHARGS1}" >>"${LOGDIR}/${MIRROR}.log" 2>&1
            touch "${PUSHLOCKOWN}"

            # Step2: Wait for all the other "lock"files to appear.
            tries=0
            # We do not wait forever
            while [ ${tries} -lt ${PUSHDELAY} ]; do
                total=0
                found=0
                for file in ${PUSHLOCKS}; do
                    total=$((total + 1))
                    if [ -f ${file} ]; then
                        found=$((found + 1))
                    fi
                done
                if [ ${total} -eq ${found} ] || [ -f "${LOCKDIR}/all_stage1" ]; then
                    touch "${LOCKDIR}/all_stage1"
                    break
                fi
                tries=$((tries + 5))
                sleep 5
            done
            # In case we did not have all PUSHLOCKS and still continued, note it
            # This is a little racy, especially if the other parts decide to do this
            # at the same time, but it wont hurt more than a mail too much, so I don't care much
            if [ ${tries} -ge ${PUSHDELAY} ]; then
                echo "Failed to wait for all other mirrors. Failed ones are:" >> "${LOGDIR}/${MIRROR}.log"
                for file in ${PUSHLOCKS}; do
                    if [ ! -f ${file} ]; then
                        echo "${file}" >> "${LOGDIR}/${MIRROR}.log"
                        error "Missing Pushlockfile ${file} after waiting ${tries} second, continuing"
                    fi
                done
            fi
            rm -f "${PUSHLOCKOWN}"
        fi

        # Step3: It either timed out or we have all the "lock"files, do the rest
        # If we are doing mhop AND are called from ftpsync - we now exit.
        # That way we notify our uplink that we and all our clients are done with their
        # stage1. It can then finish its own, and if all our upstreams downlinks are done,
        # it will send us stage2.
        # If we are not doing mhop or are not called from ftpsync, we start stage2
        if [ "xtruex" = "x${FROMFTPSYNC}x" ] && [ "xmhopx" = "x${PUSHKIND}x" ]; then
            return
        else
            PUSHARGS2="sync:stage2"
            echo "Now doing the second stage push" >> "${LOGDIR}/${MIRROR}.log"
            ssh $SSH_OPTIONS "${HOSTNAME}" "${PUSHARGS} ${PUSHARGS2}" >>"${LOGDIR}/${MIRROR}.log" 2>&1
        fi
    else
        # Can't decide? Then you get nothing.
        return
    fi
}

# callback, used by ftpsync
callback () {
    # Defaults we always want, no matter what
    SSH_OPTIONS="-o BatchMode=yes -o ServerAliveInterval=45 -o ConnectTimeout=45 -o PasswordAuthentication=no"
    ssh $SSH_OPTIONS -i "$3" -o"user $1" "$2" callback:${HOSTNAME}
}

# log something (basically echo it together with a timestamp)
#
# Set $PROGRAM to a string to have it added to the output.
log () {
    if [ -z "${PROGRAM}" ]; then
        echo "$(date +"%b %d %H:%M:%S") $(hostname -s) [$$] $@"
    else
        echo "$(date +"%b %d %H:%M:%S") $(hostname -s) ${PROGRAM}[$$]: $@"
    fi
}

# log the message using log() but then also send a mail
# to the address configured in MAILTO (if non-empty)
error () {
    log "$@"
    if [ -z "${MAILTO}" ]; then
        echo "$@" | mail -e -s "[$PROGRAM@$(hostname -s)] ERROR [$$]" ${MAILTO}
    fi
}

# run a hook
# needs array variable HOOK setup with HOOKNR being a number an HOOKSCR
# the script to run.
hook () {
    ARGS='HOOK[@]'
    local "${!ARGS}"
    if [ -n "${HOOKSCR}" ]; then
        log "Running hook $HOOKNR: ${HOOKSCR}"
        set +e
        ${HOOKSCR}
        result=$?
        set -e
        log "Back from hook $HOOKNR, got returncode ${result}"
        return $result
    else
        return 0
    fi
}

# Return the list of 2-stage mirrors.
get2stage() {
    egrep '^(staged|mhop)' "${MIRRORS}" | {
        while read MTYPE MLNAME MHOSTNAME MUSER MPROTO MKEYFILE; do
            PUSHLOCKS="${LOCKDIR}/${MLNAME}.stage1 ${PUSHLOCKS}"
        done
        echo "$PUSHLOCKS"
    }
}

# Rotate logfiles
savelog() {
    torotate="$1"
    count=${2:-${LOGROTATE}}
    while [ ${count} -gt 0 ]; do
        prev=$(( count - 1 ))
        if [ -e "${torotate}.${prev}" ]; then
            mv "${torotate}.${prev}" "${torotate}.${count}"
        fi
        count=$prev
    done
    mv "${torotate}" "${torotate}.0"
}
