source: trunk/cereal/fs/usr/bin/cereal @ 651

#!/bin/bash

# cereal: command line interface to cereal screen serial loggers
#
# The cereal scripts were written by
# Jameson Rollins <jrollins@fifthhorseman.net>
# and
# Daniel Kahn Gillmor <dkg-debian.org@fifthhorseman.net>.
#
# They are Copyright 2007, and are all released under the GPL, version 3
# or later.

##################################################
CMD=$(basename $0)

SHAREDIR=${SHAREDIR:-"/usr/share/cereal"}
export SHAREDIR
source "$SHAREDIR/common"
##################################################

function usage {
cat <<EOF
Usage: $CMD <subcommand> [options] [args]
Cereal client program.

subcommands:
  attach (a) SESSION                      attach to session
  follow (f) [options] SESSION            follow session log
    -c (--cat)                              cat log instead of follow
    -p (--path)                             output just log file path
  list (l) [SESSION]...                   list session(s)
  help (h,?)                              this help

EOF
}

attach() {
    SESSION="$1"

    if [ -z "$SESSION" ] ; then
        failure "Not enough input arguments.  Type '$CMD help' for more info."
    elif ! is_session "$SESSION" ; then
        failure "Session '$SESSION' not found.
Type 'cereal list' to list sessions."
    elif ! is_running "$SESSION" ; then
        failure "Session '$SESSION' not running."
    elif ! can_attach "$SESSION" "$USER" ; then
        failure "You are not allowed to attach to session '$SESSION'."
    fi

    log_write "$SESSION" "user '$USER' attaching to session..."
    screen -r -S "cereal:$SESSION" || failure "Could not reattach screen."
    log_write "$SESSION" "user '$USER' detached from session."
}

log_follow() {
    tail -n 100 -F "$LOG"
}
export -f log_follow

log_cat() {
    cat "$LOG"
}
export -f log_cat

log_pwd() {
    echo "$LOG"
}
export -f log_pwd

follow() {
    local SESSION TEMP
    local OUTPUT="log_follow"

    TEMP=$(getopt -o cp --long cat,path -n "$CMD follow" -- "$@")
    if (( $? != 0 )) ; then
        failure "Invalid options."
    fi

    # Note the quotes around `$TEMP': they are essential!
    eval set -- "$TEMP"

    while true ; do
        case "$1" in
            -c|--cat) OUTPUT="log_cat" ; shift 1 ;;
            -p|--path) OUTPUT="log_pwd" ; shift 1 ;;
            --) shift ;;
            *)
                if (( $# < 1 )) ; then
                    failure "Not enough input arguments.
Type '$CMD help' for more info."
                fi
                SESSION="$1"
                break
                ;;
        esac
    done
    
    if ! is_session "$SESSION" ; then
        failure "Session '$SESSION' not found.
Type 'cereal list' to list sessions."
    elif ! can_follow "$SESSION" "$USER" ; then
        failure "You are not allowed to follow session '$SESSION'."
    fi

    LOG="$SESSIONDIR/$SESSION/log/main/current"
    if [ "$OUTPUT" = 'log_follow' -o "$OUTPUT" = 'log_cat' ] ; then
        echo "############################################################"
        echo "### cereal log: $SESSION"
        echo -n "### "
        list "$SESSION"
        echo "### log file: $LOG"
        echo "############################################################"
    fi
    $OUTPUT
}

###############################################################
### MAIN

handle_command() {

    COMMAND="$1"

    [ "$COMMAND" ] || failure "Type '$CMD help' for usage."
    shift

    case $COMMAND in
        'attach'|'a')
            attach "$@"
            ;;
        'follow'|'f')
            follow "$@"
            ;;
        'list'|'l')
            list -d "$@" || failure "There are no sessions." 1
            ;;
        'help'|'h'|'?')
            usage
            ;;
        *)
            failure "Unknown command: '$COMMAND'
Type '$CMD help' for usage."
            ;;
    esac

    exit "$ERR"
}

handle_command "$@"