#!/bin/sh
#
# 2005-2013 Nico Schottelius (nico-ccollect at schottelius.org)
# 2016 Darko Poljak (darko.poljak at gmail.com)
#
# This file is part of ccollect.
#
# ccollect 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.
#
# ccollect 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 ccollect. If not, see <http://www.gnu.org/licenses/>.
#
# Initially written for SyGroup (www.sygroup.ch)
# Date: Mon Nov 14 11:45:11 CET 2005

# Error upon expanding unset variables:
set -u

#
# Standard variables (stolen from cconf)
#
__pwd="$(pwd -P)"
__mydir="${0%/*}"; __abs_mydir="$(cd "$__mydir" && pwd -P)"
__myname=${0##*/}; __abs_myname="$__abs_mydir/$__myname"

#
# where to find our configuration and temporary file
#
CCOLLECT_CONF="${CCOLLECT_CONF:-/etc/ccollect}"
CSOURCES="${CCOLLECT_CONF}/sources"
CDEFAULTS="${CCOLLECT_CONF}/defaults"
CPREEXEC="${CDEFAULTS}/pre_exec"
CPOSTEXEC="${CDEFAULTS}/post_exec"
CMARKER=".ccollect-marker"

export TMP="$(mktemp "/tmp/${__myname}.XXXXXX")"
CONTROL_PIPE="/tmp/${__myname}-control-pipe"

VERSION="2.3"
RELEASE="2018-02-02"
HALF_VERSION="ccollect ${VERSION}"
FULL_VERSION="ccollect ${VERSION} (${RELEASE})"

#
# CDATE: how we use it for naming of the archives
# DDATE: how the user should see it in our output (DISPLAY)
#
CDATE="date +%Y%m%d-%H%M"
DDATE="date +%Y-%m-%d-%H:%M:%S"
SDATE="date +%s"

#
# LOCKING: use flock if available, otherwise mkdir
# Locking is done for each source so that only one instance per source
# can run.
#
# Use CCOLLECT_CONF directory for lock files.
# This directory can be set arbitrary so it is writable for user
# executing ccollect.
LOCKDIR="${CCOLLECT_CONF}"
# printf pattern: ccollect_<source>.lock
LOCKFILE_PATTERN="ccollect_%s.lock"
LOCKFD=4

#
# locking functions using flock
#
lock_flock()
{
    # $1 = source to backup
    lockfile="${LOCKDIR}/$(printf "${LOCKFILE_PATTERN}" "$1")"
    eval "exec ${LOCKFD}> ${lockfile}"

    flock -n ${LOCKFD} && return 0 || return 1
}

unlock_flock()
{
    # $1 = source to backup
    lockfile="${LOCKDIR}/$(printf "${LOCKFILE_PATTERN}" "$1")"
    eval "exec ${LOCKFD}>&-"
    rm -f "${lockfile}"
}

#
# locking functions using mkdir (mkdir is atomic)
#
lock_mkdir()
{
    # $1 = source to backup
    lockfile="${LOCKDIR}/$(printf "${LOCKFILE_PATTERN}" "$1")"

    mkdir "${lockfile}" && return 0 || return 1
}

unlock_mkdir()
{
    # $1 = source to backup
    lockfile="${LOCKDIR}/$(printf "${LOCKFILE_PATTERN}" "$1")"

    rmdir "${lockfile}"
}

#
# determine locking tool: flock or mkdir
#
if $(which flock > /dev/null 2>&1)
then
    lockf="lock_flock"
    unlockf="unlock_flock"
else
    lockf="lock_mkdir"
    unlockf="unlock_mkdir"
fi

#
# unset values
#
PARALLEL=""
MAX_JOBS=""
USE_ALL=""
LOGFILE=""
SYSLOG=""
# e - only errors, a - all output
LOGLEVEL="a"
LOGONLYERRORS=""

#
# catch signals
#
TRAPFUNC="rm -f \"${TMP}\""
trap "${TRAPFUNC}" 1 2 15

#
# Functions
#

# check if we are running interactive or non-interactive
# see: http://www.tldp.org/LDP/abs/html/intandnonint.html
_is_interactive()
{
    [ -t 0 -o -p /dev/stdin ]
}

add_name()
{
    awk "{ print \"[${name}] \" \$0 }"
}

#
# ssh-"feature": we cannot do '... read ...; ssh  ...; < file',
# because ssh reads stdin! -n does not work -> does not ask for password
# Also allow deletion for files without the given suffix
#
delete_from_file()
{
    file="$1"; shift
    suffix="" # It will be set, if deleting incomplete backups.
    [ $# -eq 1 ] && suffix="$1" && shift
    while read to_remove; do
        set -- "$@" "${to_remove}"
        if [ "${suffix}" ]; then
            to_remove_no_suffix="$(echo ${to_remove} | sed "s/$suffix\$//")"
            set -- "$@" "${to_remove_no_suffix}"
        fi
    done < "${file}"
    _techo "Removing $@ ..."
    [ "${VVERBOSE}" ] && echo rm "$@"
    rm -rf "$@" || _exit_err "Removing $@ failed."
}

display_version()
{
    echo "${FULL_VERSION}"
    exit 0
}

usage()
{
    cat << eof
${__myname}: [args] <interval name> <sources to backup>

    ccollect creates (pseudo) incremental backups

    -h, --help:              Show this help screen
    -a, --all:               Backup all sources specified in ${CSOURCES}
    -e, --errors:            Log only errors
    -j [max], --jobs [max]   Specifies the number of jobs to run simultaneously.
                             If max is not specified then parallelise all jobs.
    -l FILE, --logfile FILE  Log to specified file
    -p, --parallel:          Parallelise backup processes (deprecated from 2.0)
    -s, --syslog:            Log to syslog with tag ccollect
    -v, --verbose:           Be very verbose (uses set -x)
    -V, --version:           Print version information

    This is version ${VERSION} released on ${RELEASE}.

    Retrieve latest ccollect at http://www.nico.schottelius.org/software/ccollect/
eof
    exit 0
}

# locking functions
lock()
{
    "${lockf}" "$@" || _exit_err \
        "Only one instance of ${__myname} for source \"$1\" can run at one time."
}

unlock()
{
    "${unlockf}" "$@"
}

# time displaying echo
# stdout version
_techo_stdout()
{
    echo "$(${DDATE}): $@"
}

# syslog version
_techo_syslog()
{
    logger -t ccollect "$@"
}

# specified file version
_techo_file()
{
    _techo_stdout "$@" >> "${LOGFILE}"
}

# determine _techo version before parsing options
if _is_interactive
then
    _techof="_techo_stdout"
else
    _techof="_techo_syslog"
fi

# _techo with determined _techo version
_techo()
{
    if [ "${LOGLEVEL}" = "a" ]
    then
        "${_techof}" "$@"
    fi
}

_techo_err()
{
    _techo "Error: $@"
}

_exit_err()
{
    _techo_err "$@"
    rm -f "${TMP}"
    exit 1
}

#
# Parse options
#
while [ "$#" -ge 1 ]; do
    case "$1" in
        -a|--all)
            USE_ALL=1
            ;;
        -p|--parallel)
            _techo "Warning: -p, --parallel option is deprecated," \
                   "use -j, --jobs instead."
            PARALLEL=1
            MAX_JOBS=""
            ;;
        -j|--jobs)
            PARALLEL=1
            if [ "$#" -ge 2 ]
            then 
                case "$2" in
                    -*)
                        ;;
                    *)
                        MAX_JOBS=$2
                        shift
                        ;;
                esac
            fi
            ;;
        -e|--errors)
            LOGONLYERRORS="1"
            ;;
        -l|--logfile)
            if [ "$#" -ge 2 ]
            then
                case "$2" in
                    -*)
                        _exit_err "Missing log file"
                        ;;
                    *)
                        LOGFILE="$2"
                        shift
                        ;;
                esac
            else
                _exit_err "Missing log file"
            fi
            ;;
        -s|--syslog)
            SYSLOG="1"
            ;;
        -v|--verbose)
            set -x
            ;;
        -V|--version)
            display_version
            ;;
        --)
            # ignore the -- itself
            shift
            break
            ;;
        -h|--help|-*)
            usage
            ;;
        *)
            break
            ;;
    esac
    shift
done

# determine _techo version and logging level after parsing options
if [ "${LOGFILE}" ]
then
    _techof="_techo_file"
    LOGLEVEL="a"
elif _is_interactive
then
    if [ "${SYSLOG}" ]
    then
        _techof="_techo_syslog"
        LOGLEVEL="a"
    else
        _techof="_techo_stdout"
        LOGLEVEL="e"
    fi
else
    _techof="_techo_syslog"
    LOGLEVEL="a"
fi

if [ "${LOGFILE}" -o "${SYSLOG}" ]
then
    if [ "${LOGONLYERRORS}" ]
    then
        LOGLEVEL="e"
    fi
fi

# check that MAX_JOBS is natural number > 0
# empty string means run all in parallel
echo "${MAX_JOBS}" | grep -q -E '^[1-9][0-9]*$|^$'
if [ "$?" -ne 0 ]
then
    _exit_err "Invalid max jobs value \"${MAX_JOBS}\""
fi

#
# Setup interval
#
if [ $# -ge 1 ]; then
    export INTERVAL="$1"
    shift
else
    usage
fi

#
# Check for configuraton directory
#
[ -d "${CCOLLECT_CONF}" ] || _exit_err "No configuration found in " \
    "\"${CCOLLECT_CONF}\" (is \$CCOLLECT_CONF properly set?)"

#
# Create (portable!) source "array"
#
export no_sources=0

if [ "${USE_ALL}" = 1 ]; then
    #
    # Get sources from source configuration
    #
    ( cd "${CSOURCES}" && ls -1 > "${TMP}" ) || \
        _exit_err "Listing of sources failed. Aborting."

    while read tmp; do
        eval export source_${no_sources}=\"${tmp}\"
        no_sources=$((${no_sources}+1))
    done < "${TMP}"
else
    #
    # Get sources from command line
    #
    while [ "$#" -ge 1 ]; do
        eval arg=\"\$1\"; shift

        eval export source_${no_sources}=\"${arg}\"
        no_sources="$((${no_sources}+1))"
    done
fi

#
# Need at least ONE source to backup
#
if [ "${no_sources}" -lt 1 ]; then
    usage
else
    _techo "${HALF_VERSION}: Beginning backup using interval ${INTERVAL}"
fi

#
# Look for pre-exec command (general)
#
if [ -x "${CPREEXEC}" ]; then
    _techo "Executing ${CPREEXEC} ..."
    "${CPREEXEC}"; ret=$?
    _techo "Finished ${CPREEXEC} (return code: ${ret})."

    [ "${ret}" -eq 0 ] || _exit_err "${CPREEXEC} failed. Aborting"
fi

################################################################################
#
# Let's do the backup - here begins the real stuff
#

# in PARALLEL mode:
# * create control pipe
# * determine number of jobs to start at once
if [ "${PARALLEL}" ]; then
    mkfifo "${CONTROL_PIPE}"
    # fd 5 is tied to control pipe
    eval "exec 5<>${CONTROL_PIPE}"
    TRAPFUNC="${TRAPFUNC}; rm -f \"${CONTROL_PIPE}\""
    trap "${TRAPFUNC}" 0 1 2 15

    # determine how much parallel jobs to prestart
    if [ "${MAX_JOBS}" ]
    then
        if [ "${MAX_JOBS}" -le "${no_sources}" ]
        then
            prestart="${MAX_JOBS}"
        else
            prestart="${no_sources}"
        fi
    else
        prestart=0
    fi
fi

source_no=0
while [ "${source_no}" -lt "${no_sources}" ]; do
    #
    # Get current source
    #
    eval export name=\"\$source_${source_no}\"
    source_no=$((${source_no}+1))

    #
    # Start ourself, if we want parallel execution
    #
    if [ "${PARALLEL}" ]; then
        if [ ! "${MAX_JOBS}" ]
        then
            # run all in parallel
            "$0" "${INTERVAL}" "${name}" &
            continue
        elif [ "${prestart}" -gt 0 ]
        then
            # run prestart child if pending
            { "$0" "${INTERVAL}" "${name}"; printf '\n' >&5; } &
            prestart=$((${prestart} - 1))
            continue
        else
            # each time a child finishes we get a line from the pipe
            # and then launch another child
            while read line
            do
                { "$0" "${INTERVAL}" "${name}"; printf '\n' >&5; } &
                # get out of loop so we can contnue with main loop
                # for next source
                break
            done <&5
            continue
        fi
    fi

#
# Start subshell for easy log editing
#
(
    backup="${CSOURCES}/${name}"
    c_source="${backup}/source"
    c_dest="${backup}/destination"
    c_pre_exec="${backup}/pre_exec"
    c_post_exec="${backup}/post_exec"

    #
    # Stderr to stdout, so we can produce nice logs
    #
    exec 2>&1

    #
    # Record start of backup: internal and for the user
    #
    begin_s="$(${SDATE})"
    _techo "Beginning to backup"

    #
    # Standard configuration checks
    #
    if [ ! -e "${backup}" ]; then
        _exit_err "Source does not exist."
    fi

    #
    # Configuration _must_ be a directory (cconfig style)
    #
    if [ ! -d "${backup}" ]; then
        _exit_err "\"${backup}\" is not a cconfig-directory. Skipping."
    fi

    #
    # Acquire lock for source. If lock cannot be acquired, lock will exit
    # with error message.
    #
    lock "${name}"

    # redefine trap to also unlock (rm lockfile)
    TRAPFUNC="${TRAPFUNC}; unlock \"${name}\""
    trap "${TRAPFUNC}" 1 2 15

    #
    # First execute pre_exec, which may generate destination or other parameters
    #
    if [ -x "${c_pre_exec}" ]; then
        _techo "Executing ${c_pre_exec} ..."
        "${c_pre_exec}"; ret="$?"
        _techo "Finished ${c_pre_exec} (return code ${ret})."

        [ "${ret}" -eq 0 ] || _exit_err "${c_pre_exec} failed. Skipping."
    fi

    #
    # Read source configuration
    #
    for opt in verbose very_verbose summary exclude rsync_options \
                  delete_incomplete rsync_failure_codes  \
                  mtime quiet_if_down ; do
        if [ -f "${backup}/${opt}" -o -f "${backup}/no_${opt}"  ]; then
            eval c_$opt=\"${backup}/$opt\"
        else
            eval c_$opt=\"${CDEFAULTS}/$opt\"
        fi
    done

    #
    # Interval definition: First try source specific, fallback to default
    #
    c_interval="$(cat "${backup}/intervals/${INTERVAL}" 2>/dev/null)"

    if [ -z "${c_interval}" ]; then
        c_interval="$(cat "${CDEFAULTS}/intervals/${INTERVAL}" 2>/dev/null)"

        if [ -z "${c_interval}" ]; then
            _exit_err "No definition for interval \"${INTERVAL}\" found. Skipping."
        fi
    fi

    #
    # Sort by ctime (default) or mtime (configuration option)
    #
    if [ -f "${c_mtime}" ] ; then
        TSORT="t"
    else
        TSORT="tc"
    fi

    #
    # Source configuration checks
    #
    if [ ! -f "${c_source}" ]; then
        _exit_err "Source description \"${c_source}\" is not a file. Skipping."
    else
        source=$(cat "${c_source}"); ret="$?"
        if [ "${ret}" -ne 0 ]; then
            _exit_err "Source ${c_source} is not readable. Skipping."
        fi
    fi

    #
    # Destination is a path
    #
    if [ ! -f "${c_dest}" ]; then
        _exit_err "Destination ${c_dest} is not a file. Skipping."
    else
        ddir="$(cat "${c_dest}")"; ret="$?"
        if [ "${ret}" -ne 0 ]; then
            _exit_err "Destination ${c_dest} is not readable. Skipping."
        fi
    fi

    #
    # Parameters: ccollect defaults, configuration options, user options
    #

    #
    # Rsync standard options (archive will be added after is-up-check)
    #
    set -- "$@" "--delete" "--numeric-ids" "--relative"    \
                    "--delete-excluded" "--sparse"

    #
    # Exclude list
    #
    if [ -f "${c_exclude}" ]; then
        set -- "$@" "--exclude-from=${c_exclude}"
    fi

    #
    # Output a summary
    #
    if [ -f "${c_summary}" ]; then
        set -- "$@" "--stats"
    fi

    #
    # Verbosity for rsync, rm, and mkdir
    #
    VVERBOSE=""
    if [ -f "${c_very_verbose}" ]; then
        set -- "$@" "-vv"
        VVERBOSE="-v"
    elif [ -f "${c_verbose}" ]; then
        set -- "$@" "-v"
    fi

    #
    # Extra options for rsync provided by the user
    #
    if [ -f "${c_rsync_options}" ]; then
        while read line; do
            # Trim line.
            ln=$(echo "${line}" | awk '{$1=$1;print;}')
            # Only if ln is non zero length string.
            #
            # If ln is empty then rsync '' DEST evaluates
            # to transfer current directory to DEST which would
            # with specific options destroy DEST content.
            if [ -n "${ln}" ]
            then
                set -- "$@" "${ln}"
            fi
        done < "${c_rsync_options}"
    fi

    #
    # Check: source is up and accepting connections (before deleting old backups!)
    #
    if ! rsync "$@" "${source}" >/dev/null 2>"${TMP}" ; then
        if [ ! -f "${c_quiet_if_down}" ]; then
            cat "${TMP}"
        fi
        _exit_err "Source ${source} is not readable. Skipping."
    fi

    #
    # Add --archive for real backup (looks nice in front)
    #
    set -- "--archive" "$@"

    #
    # Check: destination exists?
    #
    cd "${ddir}" || _exit_err "Cannot change to ${ddir}. Skipping."

    #
    # Check incomplete backups (needs echo to remove newlines)
    #
    ls -1 | grep "${CMARKER}\$" > "${TMP}"; ret=$?

    if [ "$ret" -eq 0 ]; then
        _techo "Incomplete backups: $(echo $(cat "${TMP}"))"
        if [ -f "${c_delete_incomplete}" ]; then
            delete_from_file "${TMP}" "${CMARKER}"
        fi
    fi

    #
    # Check: maximum number of backups is reached?
    #
    count="$(ls -1 | grep -c "^${INTERVAL}\\.")"

    _techo "Existing backups: ${count} Total keeping backups: ${c_interval}"

    if [ "${count}" -ge "${c_interval}" ]; then
        remove="$((${count} - ${c_interval} + 1))"
        _techo "Removing ${remove} backup(s)..."

        ls -${TSORT}1r | grep "^${INTERVAL}\\." | head -n "${remove}" > "${TMP}" || \
                _exit_err "Listing old backups failed"

        delete_from_file "${TMP}"
    fi

    #
    # Check for backup directory to clone from: Always clone from the latest one!
    #
    last_dir="$(ls -${TSORT}p1 | grep '/$' | head -n 1)" || \
        _exit_err "Failed to list contents of ${ddir}."

    #
    # Clone from old backup, if existing
    #
    if [ "${last_dir}" ]; then
        set -- "$@" "--link-dest=${ddir}/${last_dir}"
        _techo "Hard linking from ${last_dir}"
    fi

    #
    # Include current time in name, not the time when we began to remove above
    #
    export destination_name="${INTERVAL}.$(${CDATE}).$$-${source_no}"
    export destination_dir="${ddir}/${destination_name}"

    #
    # Mark backup running and go back to original directory
    #
    touch "${destination_dir}${CMARKER}"
    cd "${__abs_mydir}" || _exit_err "Cannot go back to ${__abs_mydir}."

    #
    # the rsync part
    #
    _techo "Transferring files..."
    rsync "$@" "${source}" "${destination_dir}"; ret=$?
    _techo "Finished backup (rsync return code: $ret)."

    #
    # Set modification time (mtime) to current time, if sorting by mtime is enabled
    #
    [ -f "$c_mtime" ] && touch "${destination_dir}"

    #
    # Check if rsync exit code indicates failure.
    #
    fail=""
    if [ -f "$c_rsync_failure_codes" ]; then
        while read code ; do
            if [ "$ret" = "$code" ]; then
                fail=1
            fi
        done <"${c_rsync_failure_codes}"
    fi

    #
    # Remove marking here unless rsync failed.
    #
    if [ -z "$fail" ]; then
        rm "${destination_dir}${CMARKER}" || \
            _exit_err "Removing ${destination_dir}${CMARKER} failed."
        if [ "${ret}" -ne 0 ]; then
            _techo "Warning: rsync exited non-zero, the backup may be broken (see rsync errors)."
        fi
    else
        _techo "Warning: rsync failed with return code $ret."
    fi

    #
    # post_exec
    #
    if [ -x "${c_post_exec}" ]; then
        _techo "Executing ${c_post_exec} ..."
        "${c_post_exec}"; ret=$?
        _techo "Finished ${c_post_exec}."

        if [ "${ret}" -ne 0 ]; then
            _exit_err "${c_post_exec} failed."
        fi
    fi

    #
    # Time calculation
    #
    end_s="$(${SDATE})"
    full_seconds="$((${end_s} - ${begin_s}))"
    hours="$((${full_seconds} / 3600))"
    minutes="$(((${full_seconds} % 3600) / 60))"
    seconds="$((${full_seconds} % 60))"

    _techo "Backup lasted: ${hours}:${minutes}:${seconds} (h:m:s)"

    unlock "${name}"
) | add_name
done

#
# Be a good parent and wait for our children, if they are running wild parallel
# After all children are finished then remove control pipe.
#
if [ "${PARALLEL}" ]; then
    _techo "Waiting for children to complete..."
    wait
    rm -f "${CONTROL_PIPE}"
fi

#
# Look for post-exec command (general)
#
if [ -x "${CPOSTEXEC}" ]; then
    _techo "Executing ${CPOSTEXEC} ..."
    "${CPOSTEXEC}"; ret=$?
    _techo "Finished ${CPOSTEXEC} (return code: ${ret})."

    if [ "${ret}" -ne 0 ]; then
        _techo "${CPOSTEXEC} failed."
    fi
fi

rm -f "${TMP}"
_techo "Finished"