#! /bin/sh
# #############################################################################

       NAME_="cpverify"
       HTML_="verify backup files"
    PURPOSE_="verify that copied or burned files have been written error free"
   SYNOPSIS_="$NAME_ [-hml] -d <source_dir> <copy_dir> | -s <source_file> -c <copy_file>"
   REQUIRES_="standard GNU commands, md5sum"
    VERSION_="1.3"
       DATE_="2002-12-28; last update: 2004-12-23"
     AUTHOR_="Dawid Michalczyk <dm@eonworks.com>"
        URL_="www.comp.eonworks.com"
   CATEGORY_="file"
   PLATFORM_="Linux"
      SHELL_="bash"
 DISTRIBUTE_="yes"

# #############################################################################
# This program is distributed under the terms of the GNU General Public License

# HISTORY:
# 2002-12-28 v1.0
# 2004-06-14 v1.1 - complete rewrite
# 2004-08-18 v1.2 - added more argument checking
#                 - added support for relative and full paths
# 2004-12-23 v1.3 - added support for files with spaces
#                 - improved matching of FAILED files

usage () {

echo >&2 "$NAME_ $VERSION_ - $PURPOSE_
Usage: $SYNOPSIS_
Requires: $REQUIRES_
Options:
     -s <source_file>, source file location
     -c <copy_file>, copied file location
     -d <source_dir> <copy_dir>, paths to the source and copy dirs
     -h, usage and options (this help)
     -m, manual
     -l, see this script"
    exit 1
}

manual () { echo >&2 "

NAME

    $NAME_ $VERSION_ - $PURPOSE_

SYNOPSIS

    $SYNOPSIS_

DESCRIPTION

    $NAME_ verifies that a file or directory structure has been copied or
    burned without errors. That is, the copied file(s) is exactly the same
    as the original. This is done by calculating a cryptographic checksum
    using the md5 message-digest algorithm on each file from the source and
    the copy destination. The checksums for each file are then compared. Any
    difference indicates that the copied file is not the same as the
    original source file. Name of the file that fail to match the original
    source file is printed to stdo.

    Initially this script was written to verify that a CD ROM backup has
    been burned error free. Currently the script can verify whole
    directory trees as well as single files.

EXAMPLES

    To verify that a file ~/dev/src.tar.bz2 is the same as ~/backup/src.tar.bz2

        $ $NAME_ -s ~/dev/src.tar.bz2 -c ~/backup/src.tar.bz2

    To verify that dir structure ~/backup have been burned correctly to
    the /mnt/cdrom

        $ $NAME_ -d ~/backup /mnt/cdrom

    To verify that two CD ROMS are identical, where the mounting points are
    /mnt/cdrom and  /mnt/cdrom2

        $ $NAME_ -d /mnt/cdrom /mnt/cdrom2

NOTE

    In August 2004 a collision has been found in MD5 and other hash functions.
    This means that it is possible to find two messages with the same hash, but
    the attacker can't determine what the hash will be. Immediate implications of
    this depend on how and where MD5 is used. I can only advise to learn about
    this issue and judge whether it is safe to keep on using MD5 until it will
    get replaced by a safer alternative.

AUTHOR

    $AUTHOR_ Suggestions and bug reports are welcome.
    For updates and more scripts visit $URL_

"; exit 1; }


# args check
[ $# -eq 0 ] && { echo >&2 missing argument, type $NAME_ -h for help; exit 1; }

# tmp file set up
tmp_dir=/tmp/${RANDOM}${RANDOM}
mkdir $tmp_dir
tmp_1=$tmp_dir/tmp.${RANDOM}${RANDOM}

# signal trapping and tmp file removal
trap 'rm -f $tmp_1; rmdir $tmp_dir >/dev/null 2>&1' 0
trap "exit 1" 1 2 3 15

# var init
source_file=
copy_file=
check_dir=

while getopts hmlds:c: options; do

    case "$options" in
        s) source_file="$OPTARG" ;;
        c) copy_file="$OPTARG" ;;
        d) check_dir=on ;;
        h) usage ;;
        m) manual | more; exit 1 ;;
        l) more $0; exit 1 ;;
       \?) echo invalid argument, type $NAME_ -h for help; exit 1 ;;

    esac

done
shift $(( $OPTIND - 1 ))

# main
if [[ -n $check_dir ]];then # checking dir structures

    [ -d "$1" ] || { echo >&2 source dir "$1" does not exist; exit 1; }
    [ -d "$2" ] || { echo >&2 copy dir "$2" does not exist; exit 1; }

    # relative and full path support
    sdir=($(cd "$1"; pwd;))
    cdir=($(cd "$2"; pwd;))

    cd "$sdir" # source dir
    find . -type f -print0 | xargs -0 md5sum > $tmp_1

    cd "$cdir" # copy dir
    md5sum --check $tmp_1 | grep -e ": FAILED"$ -e ^"md5sum: WARNING: "
    [[ $? == 0 ]] && exit 1


elif [[ -n $source_file && -n $copy_file ]];then # checking files

    [ -f "$source_file" ] || { echo >&2 source file "$source_file" does not exist; exit 1; }
    [ -f "$copy_file" ] || { echo >&2 copy file "$copy_file" does not exist; exit 1; }

    source=$(md5sum "$source_file" | { read sum path ; echo $sum; })
    copy=$(md5sum "$copy_file" | { read sum path ; echo $sum; }) 

    if [[ $source != $copy ]];then
        echo WARNING: "$source_file" is different from "$copy_file"
        exit 1
    fi
    
else
    echo missing argument, type $NAME_ -h for help
    exit 1
fi