Initial working version for multi ISO support
[grml2usb.git] / grml2usb.py
index 2efedc3..6b0a381 100755 (executable)
@@ -1,22 +1,63 @@
 #!/usr/bin/env python
-# Filename:      grml2usb
-# Purpose:       install grml-system to usb-device
-# Authors:       grml-team (grml.org), (c) Michael Prokop <mika@grml.org>
-# Bug-Reports:   see http://grml.org/bugs/
-# License:       This file is licensed under the GPL v2 or any later version.
-################################################################################
+# -*- coding: utf-8 -*-
+"""
+grml2usb
+~~~~~~~~
 
-prog_version = "0.0.1"
+This script installs a grml system (running system / ISO[s]) to a USB device
 
-import os, sys
+:copyright: (c) 2009 by Michael Prokop <mika@grml.org>
+:license: GPL v2 or any later version
+:bugreports: http://grml.org/bugs/
+
+TODO
+----
+
+* code improvements:
+  - improve error handling :)
+  - get rid of all TODOs in code :)
+  - use 'with open("...", "w") as f: ... f.write("...")'
+  - simplify functions/code as much as possible -> audit
+* implement missing options (--kernel, --initrd, --uninstall,...)
+* validate partition schema/layout: is the partition schema ok and the bootable flag set?
+* implement logic for storing information about copied files -> register every file in a set()
+* the last line in bootsplash (boot.msg) should mention all installed grml flavours
+* extend flavour's syslinux configuration
+* graphical version? :)
+"""
+
+from __future__ import with_statement
+import os, re, subprocess, sys, tempfile
 from optparse import OptionParser
+from os.path import exists, join, abspath
+from os import pathsep
+from inspect import isroutine, isclass
+import logging
+import datetime, time
 
-# cmdline parsing {{{
-usage = "usage: %prog [options] arg1 arg2"
-parser = OptionParser(usage=usage)
+# global variables
+PROG_VERSION = "0.0.1"
+skip_mbr = False # By default we don't want to skip it; TODO - can we get rid of that?
+mounted = set()  # register mountpoints
+tmpfiles = set() # register tmpfiles
+datestamp= time.mktime(datetime.datetime.now().timetuple()) # unique identifier for syslinux.cfg
+
+# cmdline parsing
+usage = "Usage: %prog [options] <[ISO[s] | /live/image]> </dev/ice>\n\
+\n\
+%prog installs a grml ISO to an USB device to be able to boot from it.\n\
+Make sure you have at least a grml ISO or a running grml system (/live/image),\n\
+syslinux (just run 'aptitude install syslinux' on Debian-based systems)\n\
+and root access."
 
-parser.add_option("--bootoptions", dest="bootoptions", action="store", type="string",
+parser = OptionParser(usage=usage)
+parser.add_option("--bootoptions", dest="bootoptions",
+                  action="store", type="string",
                   help="use specified bootoptions as defaut")
+parser.add_option("--bootloader-only", dest="bootloaderonly", action="store_true",
+                  help="do not copy files only but just install a bootloader")
+parser.add_option("--copy-only", dest="copyonly", action="store_true",
+                  help="copy files only and do not install bootloader")
 parser.add_option("--dry-run", dest="dryrun", action="store_true",
                   help="do not actually execute any commands")
 parser.add_option("--fat16", dest="fat16", action="store_true",
@@ -31,68 +72,701 @@ parser.add_option("--kernel", dest="kernel", action="store", type="string",
                   help="install specified kernel instead of the default")
 parser.add_option("--mbr", dest="mbr", action="store_true",
                   help="install master boot record (MBR) on the device")
+parser.add_option("--quiet", dest="quiet", action="store_true",
+                  help="do not output anything than errors on console")
 parser.add_option("--squashfs", dest="squashfs", action="store", type="string",
                   help="install specified squashfs file instead of the default")
+parser.add_option("--uninstall", dest="uninstall", action="store_true",
+                  help="remove grml ISO files")
 parser.add_option("--verbose", dest="verbose", action="store_true",
                   help="enable verbose mode")
 parser.add_option("-v", "--version", dest="version", action="store_true",
                   help="display version and exit")
-
 (options, args) = parser.parse_args()
-# }}}
 
-# FIXME: implement argument handling
-def execute(command):
+
+def cleanup():
+    """TODO
+    """
+
+    logging.info("Cleaning up")
+    proc = subprocess.Popen(["sync"])
+    proc.wait()
+
+    try:
+        for device in mounted:
+            unmount(device, "")
+    # ignore: RuntimeError: Set changed size during iteration
+    except:
+        pass
+
+def get_function_name(obj):
+    if not (isroutine(obj) or isclass(obj)):
+        obj = type(obj)
+    return obj.__module__ + '.' + obj.__name__
+
+
+def execute(f, *args):
     """Wrapper for executing a command. Either really executes
     the command (default) or when using --dry-run commandline option
     just displays what would be executed."""
+    # demo: execute(subprocess.Popen, (["ls", "-la"]))
     if options.dryrun:
-        print "would execute %s now" % command
+        logging.debug('dry-run only: %s(%s)' % (get_function_name(f), ', '.join(map(repr, args))))
     else:
-        print "executing %s" % command
+        return f(*args)
 
-def install_syslinux(device):
-    """Install syslinux on specified device."""
-    print("syslinux %s") % device
 
-def install_grub(device):
-    """Install grub on specified device."""
-    print("grub-install %s") % device
+def is_exe(fpath):
+    """Check whether a given file can be executed
 
-def install_bootloader(device):
-    """Install bootloader on specified device."""
-    if options.grub:
-        install_grub(device)
+    @fpath: full path to file
+    @return:"""
+    return os.path.exists(fpath) and os.access(fpath, os.X_OK)
+
+
+def which(program):
+    """Check whether a given program is available in PATH
+
+    @program: name of executable"""
+    fpath, fname = os.path.split(program)
+    if fpath:
+        if is_exe(program):
+            return program
     else:
-        install_syslinux(device)
+        for path in os.environ["PATH"].split(os.pathsep):
+            exe_file = os.path.join(path, program)
+            if is_exe(exe_file):
+                return exe_file
+
+    return None
+
+
+def search_file(filename, search_path='/bin' + pathsep + '/usr/bin'):
+    """Given a search path, find file"""
+    file_found = 0
+    paths = search_path.split(pathsep)
+    for path in paths:
+        for current_dir, directories, files in os.walk(path):
+            if exists(join(current_dir, filename)):
+                file_found = 1
+                break
+    if file_found:
+        return abspath(join(current_dir, filename))
+    else:
+        return None
+
 
 def check_uid_root():
     """Check for root permissions"""
     if not os.geteuid()==0:
         sys.exit("Error: please run this script with uid 0 (root).")
 
+
+def install_syslinux(device, dry_run=False):
+    # TODO
+    """Install syslinux on specified device."""
+
+    # syslinux -d boot/isolinux /dev/sdb1
+    logging.info("Installing syslinux as bootloader")
+    logging.debug("syslinux -d boot/syslinux %s" % device)
+    proc = subprocess.Popen(["syslinux", "-d", "boot/syslinux", device])
+    proc.wait()
+    if proc.returncode != 0:
+        raise Exception, "error executing syslinux"
+
+
+def generate_grub_config(grml_flavour):
+    """Generate grub configuration for use via menu,lst"""
+
+    # TODO
+    # * install main part of configuration just *once* and append
+    #   flavour specific configuration only
+    # * what about systems using grub2 without having grub1 available?
+    # * support grub2?
+
+    return("""\
+# misc options:
+timeout 30
+# color red/blue green/black
+splashimage=/boot/grub/splash.xpm.gz
+foreground  = 000000
+background  = FFCC33
+
+# define entries:
+title %(grml_flavour)s  - Default boot (using 1024x768 framebuffer)
+kernel /boot/release/%(grml_flavour)s/linux26 apm=power-off lang=us vga=791 quiet boot=live nomce module=%(grml_flavour)s
+initrd /boot/release/%(grml_flavour)s/initrd.gz
+
+# TODO: extend configuration :)
+""" % locals())
+
+
+def generate_isolinux_splash(grml_flavour):
+    """Generate bootsplash for isolinux/syslinux"""
+
+    # TODO
+    # * adjust last bootsplash line
+
+    grml_name = grml_flavour
+
+    return("""\
+\ f17\f\18/boot/syslinux/logo.16
+
+Some information and boot options available via keys F2 - F10. http://grml.org/
+%(grml_name)s
+""" % locals())
+
+def generate_main_syslinux_config(grml_flavour, grml_bootoptions):
+    """Generate main configuration for use in syslinux.cfg"""
+
+    # TODO
+    # * install main part of configuration just *once* and append
+    #   flavour specific configuration only
+    # * unify isolinux and syslinux setup ("INCLUDE /boot/...")
+    #   as far as possible
+
+    local_datestamp = datestamp
+
+    return("""\
+## main syslinux configuration - generated by grml2usb [main config generated at: %(local_datestamp)s]
+# use this to control the bootup via a serial port
+# SERIAL 0 9600
+DEFAULT grml
+TIMEOUT 300
+PROMPT 1
+DISPLAY /boot/syslinux/boot.msg
+F1 /boot/syslinux/boot.msg
+F2 /boot/syslinux/f2
+F3 /boot/syslinux/f3
+F4 /boot/syslinux/f4
+F5 /boot/syslinux/f5
+F6 /boot/syslinux/f6
+F7 /boot/syslinux/f7
+F8 /boot/syslinux/f8
+F9 /boot/syslinux/f9
+F10 /boot/syslinux/f10
+## end of main configuration
+
+# flavour specific configuration for grml
+LABEL  grml
+KERNEL /boot/release/%(grml_flavour)s/linux26
+APPEND initrd=/boot/release/%(grml_flavour)s/initrd.gz apm=power-off boot=live nomce quiet module=%(grml_flavour)s %(grml_bootoptions)s
+
+""" % locals())
+
+def generate_flavour_specific_syslinux_config(grml_flavour, bootoptions):
+    """Generate flavour specific configuration for use in syslinux.cfg"""
+
+    local_datestamp = datestamp
+
+    return("""\
+
+# flavour specific configuration for %(grml_flavour)s [grml2usb for %(grml_flavour)s: %(local_datestamp)s]
+LABEL  %(grml_flavour)s
+KERNEL /boot/release/%(grml_flavour)s/linux26
+APPEND initrd=/boot/release/%(grml_flavour)s/initrd.gz apm=power-off boot=live nomce quiet module=%(grml_flavour)s %(bootoptions)s
+""" % locals())
+
+
+def install_grub(device, dry_run=False):
+    """Install grub on specified device."""
+    logging.critical("TODO: grub-install %s"  % device)
+
+
+def install_bootloader(partition, dry_run=False):
+    """Install bootloader on device."""
+
+    # Install bootloader on the device (/dev/sda),
+    # not on the partition itself (/dev/sda1)?
+#    if partition[-1:].isdigit():
+#        device = re.match(r'(.*?)\d*$', partition).group(1)
+#    else:
+#        device = partition
+
+    if options.grub:
+        install_grub(partition, dry_run)
+    else:
+        install_syslinux(partition, dry_run)
+
+
+def is_writeable(device):
+    """Check if the device is writeable for the current user"""
+
+    if not device:
+        return False
+        #raise Exception, "no device for checking write permissions"
+
+    if not os.path.exists(device):
+        return False
+
+    return os.access(device, os.W_OK) and os.access(device, os.R_OK)
+
+def install_mbr(device, dry_run=False):
+    """Install a default master boot record on given device
+
+    @device: device where MBR should be installed to"""
+
+    if not is_writeable(device):
+        raise IOError, "device not writeable for user"
+
+    lilo = '/grml/git/grml2usb/lilo/lilo.static' # FIXME
+
+    if not is_exe(lilo):
+        raise Exception, "lilo executable not available."
+
+    # to support -A for extended partitions:
+    logging.info("Installing MBR")
+    logging.debug("%s -S /dev/null -M %s ext" % (lilo, device))
+    proc = subprocess.Popen([lilo, "-S", "/dev/null", "-M", device, "ext"])
+    proc.wait()
+    if proc.returncode != 0:
+        raise Exception, "error executing lilo"
+
+    # activate partition:
+    logging.debug("%s -S /dev/null -A %s 1" % (lilo, device))
+    if not dry_run:
+        proc = subprocess.Popen([lilo, "-S", "/dev/null", "-A", device, "1"])
+        proc.wait()
+        if proc.returncode != 0:
+            raise Exception, "error executing lilo"
+
+    # lilo's mbr is broken, use the one from syslinux instead:
+    logging.debug("cat /usr/lib/syslinux/mbr.bin > %s" % device)
+    if not dry_run:
+        try:
+            # TODO -> use Popen instead?
+            retcode = subprocess.call("cat /usr/lib/syslinux/mbr.bin > "+ device, shell=True)
+            if retcode < 0:
+                logging.critical("Error copying MBR to device (%s)" % retcode)
+        except OSError, error:
+            logging.critical("Execution failed:", error)
+
+
+def register_tmpfile(path):
+    """TODO
+    """
+
+    tmpfiles.add(path)
+
+
+def unregister_tmpfile(path):
+    """TODO
+    """
+
+    if path in tmpfiles:
+        tmpfiles.remove(path)
+
+
+def register_mountpoint(target):
+    """TODO
+    """
+
+    mounted.add(target)
+
+
+def unregister_mountpoint(target):
+    """TODO
+    """
+
+    if target in mounted:
+        mounted.remove(target)
+
+
+def mount(source, target, options):
+    """Mount specified source on given target
+
+    @source: name of device/ISO that should be mounted
+    @target: directory where the ISO should be mounted to
+    @options: mount specific options"""
+
+#   notice: dry_run does not work here, as we have to locate files, identify flavour,...
+    logging.debug("mount %s %s %s" % (options, source, target))
+    proc = subprocess.Popen(["mount"] + list(options) + [source, target])
+    proc.wait()
+    if proc.returncode != 0:
+        raise Exception, "Error executing mount"
+    else:
+        logging.debug("register_mountpoint(%s)" % target)
+        register_mountpoint(target)
+
+def unmount(target, options):
+    """Unmount specified target
+
+    @target: target where something is mounted on and which should be unmounted
+    @options: options for umount command"""
+
+    # make sure we unmount only already mounted targets
+    target_unmount = False
+    mounts = open('/proc/mounts').readlines()
+    mountstring = re.compile(".*%s.*" % re.escape(target))
+    for line in mounts:
+        if re.match(mountstring, line):
+            target_unmount = True
+
+    if not target_unmount:
+        logging.debug("%s not mounted anymore" % target)
+    else:
+        logging.debug("umount %s %s" % (list(options), target))
+        proc = subprocess.Popen(["umount"] + list(options) + [target])
+        proc.wait()
+        if proc.returncode != 0:
+            raise Exception, "Error executing umount"
+        else:
+            logging.debug("unregister_mountpoint(%s)" % target)
+            unregister_mountpoint(target)
+
+
+def check_for_usbdevice(device):
+    """Check whether the specified device is a removable USB device
+
+    @device: device name, like /dev/sda1 or /dev/sda
+    """
+
+    usbdevice = re.match(r'/dev/(.*?)\d*$', device).group(1)
+    usbdevice = os.path.realpath('/sys/class/block/' + usbdevice + '/removable')
+    if os.path.isfile(usbdevice):
+        is_usb = open(usbdevice).readline()
+        if is_usb == "1":
+            return 0
+        else:
+            return 1
+
+
+def check_for_fat(partition):
+    """Check whether specified partition is a valid VFAT/FAT16 filesystem
+
+    @partition: device name of partition"""
+
+    try:
+        udev_info = subprocess.Popen(["/lib/udev/vol_id", "-t", partition],stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        filesystem = udev_info.communicate()[0].rstrip()
+
+        if udev_info.returncode == 2:
+            raise Exception, "Failed to read device %s - wrong UID / permissions?" % partition
+
+        if filesystem != "vfat":
+            raise Exception, "Device %s does not contain a FAT16 partition" % partition
+
+    except OSError:
+        raise Exception, "Sorry, /lib/udev/vol_id not available."
+
+
+def mkdir(directory):
+    """Simple wrapper around os.makedirs to get shell mkdir -p behaviour"""
+
+    if not os.path.isdir(directory):
+        try:
+            os.makedirs(directory)
+        except OSError:
+            # just silently pass as it's just fine it the directory exists
+            pass
+
+
+def copy_grml_files(grml_flavour, iso_mount, target, dry_run=False):
+    """Copy files from ISO on given target"""
+
+    # TODO
+    # * provide alternative search_file() if file information is stored in a config.ini file?
+    # * catch "install: .. No space left on device" & CO
+    # * abstract copy logic to make the code shorter and get rid of spaghetti ;)
+
+    if not options.bootloaderonly:
+           logging.info("Copying files. This might take a while....")
+
+           squashfs = search_file(grml_flavour + '.squashfs', iso_mount)
+           squashfs_target = target + '/live/'
+           execute(mkdir, squashfs_target)
+
+           # use install(1) for now to make sure we can write the files afterwards as normal user as well
+           logging.debug("cp %s %s" % (squashfs, target + '/live/' + grml_flavour + '.squashfs'))
+           proc = execute(subprocess.Popen, ["install", "--mode=664", squashfs, squashfs_target + grml_flavour + ".squashfs"])
+           proc.wait()
+
+           filesystem_module = search_file('filesystem.module', iso_mount)
+           logging.debug("cp %s %s" % (filesystem_module, squashfs_target + grml_flavour + '.module'))
+           proc = execute(subprocess.Popen, ["install", "--mode=664", filesystem_module, squashfs_target + grml_flavour + '.module'])
+           proc.wait()
+
+           release_target = target + '/boot/release/' + grml_flavour
+           execute(mkdir, release_target)
+
+           kernel = search_file('linux26', iso_mount)
+           logging.debug("cp %s %s" % (kernel, release_target + '/linux26'))
+           proc = execute(subprocess.Popen, ["install", "--mode=664", kernel, release_target + '/linux26'])
+           proc.wait()
+
+           initrd = search_file('initrd.gz', iso_mount)
+           logging.debug("cp %s %s" % (initrd, release_target + '/initrd.gz'))
+           proc = execute(subprocess.Popen, ["install", "--mode=664", initrd, release_target + '/initrd.gz'])
+           proc.wait()
+
+    if not options.copyonly:
+        syslinux_target = target + '/boot/syslinux/'
+        execute(mkdir, syslinux_target)
+
+        logo = search_file('logo.16', iso_mount)
+        logging.debug("cp %s %s" % (logo, syslinux_target + 'logo.16'))
+        proc = execute(subprocess.Popen, ["install", "--mode=664", logo, syslinux_target + 'logo.16'])
+        proc.wait()
+
+        for ffile in 'f2', 'f3', 'f4', 'f5', 'f6', 'f7', 'f8', 'f9', 'f10':
+            bootsplash = search_file(ffile, iso_mount)
+            logging.debug("cp %s %s" % (bootsplash, syslinux_target + ffile))
+            proc = execute(subprocess.Popen, ["install", "--mode=664", bootsplash, syslinux_target + ffile])
+            proc.wait()
+
+        grub_target = target + '/boot/grub/'
+        execute(mkdir, grub_target)
+
+        logging.debug("cp /grml/git/grml2usb/grub/splash.xpm.gz %s" % grub_target + 'splash.xpm.gz') # FIXME - path of grub
+        proc = execute(subprocess.Popen, ["install", "--mode=664", '/grml/git/grml2usb/grub/splash.xpm.gz', grub_target + 'splash.xpm.gz']) # FIXME
+        proc.wait()
+
+        logging.debug("cp /grml/git/grml2usb/grub/stage2_eltorito to %s" % grub_target + 'stage2_eltorito') # FIXME - path of grub
+        proc = execute(subprocess.Popen, ["install", "--mode=664", '/grml/git/grml2usb/grub/stage2_eltorito', grub_target + 'stage2_eltorito']) # FIXME
+        proc.wait()
+
+        if not dry_run:
+            logging.debug("Generating grub configuration")
+            #with open("...", "w") as f:
+            #f.write("bla bla bal")
+            grub_config_file = open(grub_target + 'menu.lst', 'w')
+            grub_config_file.write(generate_grub_config(grml_flavour))
+            grub_config_file.close()
+
+            logging.info("Generating syslinux configuration")
+            syslinux_cfg = syslinux_target + 'syslinux.cfg'
+
+            # install main configuration only *once*, no matter how many ISOs we have:
+            if os.path.isfile(syslinux_cfg):
+                string = open(syslinux_cfg).readline()
+                main_identifier = re.compile(".*main config generated at: %s.*" % re.escape(str(datestamp)))
+                if not re.match(main_identifier, string):
+                    syslinux_config_file = open(syslinux_cfg, 'w')
+                    logging.info("Notice: grml flavour %s is being installed as the default booting system." % grml_flavour)
+                    syslinux_config_file.write(generate_main_syslinux_config(grml_flavour, options.bootoptions))
+                    syslinux_config_file.close()
+            else:
+                    syslinux_config_file = open(syslinux_cfg, 'w')
+                    syslinux_config_file.write(generate_main_syslinux_config(grml_flavour, options.bootoptions))
+                    syslinux_config_file.close()
+
+
+            # install flavour specific configuration only *once* as well
+            # ugly - I'm pretty sure this could be smoother...
+            flavour_config = True
+            if os.path.isfile(syslinux_cfg):
+                string = open(syslinux_cfg).readlines()
+                logging.info("Notice: you can boot flavour %s using '%s' on the commandline." % (grml_flavour, grml_flavour))
+                flavour = re.compile("grml2usb for %s: %s" % (re.escape(grml_flavour), re.escape(str(datestamp))))
+                for line in string:
+                    if flavour.match(line):
+                        flavour_config = False
+
+
+            if flavour_config:
+                syslinux_config_file = open(syslinux_cfg, 'a')
+                syslinux_config_file.write(generate_flavour_specific_syslinux_config(grml_flavour, options.bootoptions))
+                syslinux_config_file.close( )
+
+            logging.debug("Generating isolinux/syslinux splash %s" % syslinux_target + 'boot.msg')
+            isolinux_splash = open(syslinux_target + 'boot.msg', 'w')
+            isolinux_splash.write(generate_isolinux_splash(grml_flavour))
+            isolinux_splash.close( )
+
+
+    # make sure we sync filesystems before returning
+    proc = subprocess.Popen(["sync"])
+    proc.wait()
+
+def uninstall_files(device):
+    """Get rid of all grml files on specified device"""
+
+    # TODO
+    logging.critical("TODO: %s" % device)
+
+
+def identify_grml_flavour(mountpath):
+    """Get name of grml flavour
+
+    @mountpath: path where the grml ISO is mounted to
+    @return: name of grml-flavour"""
+
+    version_file = search_file('grml-version', mountpath)
+
+    if version_file == "":
+        logging.critical("Error: could not find grml-version file.")
+        raise
+
+    try:
+        tmpfile = open(version_file, 'r')
+        grml_info = tmpfile.readline()
+        grml_flavour = re.match(r'[\w-]*', grml_info).group()
+    except TypeError:
+        raise
+    except:
+        logging.critical("Unexpected error:", sys.exc_info()[0])
+        raise
+
+    return grml_flavour
+
+def handle_iso(iso, device):
+    """TODO
+    """
+
+    logging.info("Using ISO %s" % iso)
+
+    if os.path.isdir(iso):
+        logging.critical("TODO: /live/image handling not yet implemented") # TODO
+    else:
+        iso_mountpoint = tempfile.mkdtemp()
+        register_tmpfile(iso_mountpoint)
+        remove_iso_mountpoint = True
+
+        mount(iso, iso_mountpoint, ["-o", "loop", "-t", "iso9660"])
+
+        if os.path.isdir(device):
+            logging.info("Specified target is a directory, not mounting therefore.")
+            device_mountpoint = device
+            remove_device_mountpoint = False
+            skip_mbr = True
+
+        else:
+            device_mountpoint = tempfile.mkdtemp()
+            register_tmpfile(device_mountpoint)
+            remove_device_mountpoint = True
+            try:
+                mount(device, device_mountpoint, "")
+            except Exception, error:
+                logging.critical("Fatal: %s" % error)
+                cleanup()
+
+        try:
+            grml_flavour = identify_grml_flavour(iso_mountpoint)
+            logging.info("Identified grml flavour \"%s\"." % grml_flavour)
+            copy_grml_files(grml_flavour, iso_mountpoint, device_mountpoint, dry_run=options.dryrun)
+        except TypeError:
+            logging.critical("Fatal: a critical error happend during execution, giving up")
+            sys.exit(1)
+        finally:
+            if os.path.isdir(iso_mountpoint) and remove_iso_mountpoint:
+                unmount(iso_mountpoint, "")
+
+                os.rmdir(iso_mountpoint)
+                unregister_tmpfile(iso_mountpoint)
+
+            if remove_device_mountpoint:
+                unmount(device_mountpoint, "")
+
+                if os.path.isdir(device_mountpoint):
+                    os.rmdir(device_mountpoint)
+                    unregister_tmpfile(device_mountpoint)
+
+        # grml_flavour_short = grml_flavour.replace('-','')
+        # logging.debug("grml_flavour_short = %s" % grml_flavour_short)
+
+
 def main():
+    """Main function [make pylint happy :)]"""
+
     if options.version:
-        print("%s %s")% (os.path.basename(sys.argv[0]), prog_version)
+        print os.path.basename(sys.argv[0]) + " " + PROG_VERSION
         sys.exit(0)
 
     if len(args) < 2:
         parser.error("invalid usage")
 
-    # check_uid_root()
+    # log handling
+    if options.verbose:
+        FORMAT = "%(asctime)-15s %(message)s"
+        logging.basicConfig(level=logging.DEBUG, format=FORMAT)
+    elif options.quiet:
+        FORMAT = "Critial: %(message)s"
+        logging.basicConfig(level=logging.CRITICAL, format=FORMAT)
+    else:
+        FORMAT = "Info: %(message)s"
+        logging.basicConfig(level=logging.INFO, format=FORMAT)
 
+    if options.dryrun:
+        logging.info("Running in simulate mode as requested via option dry-run.")
+    else:
+        check_uid_root()
+
+    # specified arguments
     device = args[len(args) - 1]
     isos = args[0:len(args) - 1]
 
-    # FIXME: check for valid blockdevice
-    if device is not None:
-        install_bootloader(device)
+    # make sure we can replace old grml2usb script and warn user when using old way of life:
+    if device.startswith("/mnt/external") or device.startswith("/mnt/usb"):
+        print "Warning: the semantics of grml2usb has changed."
+        print "Instead of using grml2usb /path/to/iso %s you might" % device
+        print "want to use grml2usb /path/to/iso /dev/... instead."
+        print "Please check out the grml2usb manpage for details."
+        f = raw_input("Do you really want to continue? y/N ")
+        if f == "y" or f == "Y":
+           pass
+        else:
+            sys.exit(1)
+
+    # make sure we have syslinux available
+    if not which("syslinux") and not options.copyonly:
+        logging.critical('Sorry, syslinux not available. Exiting.')
+        logging.critical('Please install syslinux or consider using the --grub option.')
+        sys.exit(1)
+
+    # check for vfat filesystem
+    if device is not None and not os.path.isdir(device):
+        try:
+            check_for_fat(device)
+        except Exception, error:
+            logging.critical("Execution failed: %s", error)
+            sys.exit(1)
 
+    if not check_for_usbdevice(device):
+        print "Warning: the specified device %s does not look like a removable usb device." % device
+        f = raw_input("Do you really want to continue? y/N ")
+        if f == "y" or f == "Y":
+           pass
+        else:
+            sys.exit(1)
+
+    # main operation (like installing files)
     for iso in isos:
-        print("iso = %s") % iso
+        handle_iso(iso, device)
+
+    # install MBR
+    if not options.mbr or skip_mbr:
+        logging.info("You are not using the --mbr option. Consider using it to get a working USB setup.")
+    else:
+        # make sure we install MBR on /dev/sdX and not /dev/sdX#
+        if device[-1:].isdigit():
+            mbr_device = re.match(r'(.*?)\d*$', device).group(1)
+
+        try:
+            install_mbr(mbr_device, dry_run=options.dryrun)
+        except IOError, error:
+            logging.critical("Execution failed: %s", error)
+            sys.exit(1)
+        except Exception, error:
+            logging.critical("Execution failed: %s", error)
+            sys.exit(1)
+
+    # Install bootloader only if not using the --copy-only option
+    if options.copyonly:
+        logging.info("Not installing bootloader and its files as requested via option copyonly.")
+    else:
+        install_bootloader(device, dry_run=options.dryrun)
+
+    # finally be politely :)
+    logging.info("Finished execution of grml2usb (%s). Have fun with your grml system." % PROG_VERSION)
 
 if __name__ == "__main__":
-    main()
+    try:
+        main()
+    except KeyboardInterrupt:
+        logging.info("Received KeyboardInterrupt")
+        cleanup()
 
 ## END OF FILE #################################################################
-# vim:foldmethod=marker expandtab ai ft=python
+# vim:foldmethod=marker expandtab ai ft=python tw=120 fileencoding=utf-8