github.com_openSUSE_osc/osc/conf.py

# Copyright (C) 2006-2009 Novell Inc.  All rights reserved.
# This program is free software; it may be used, copied, modified
# and distributed under the terms of the GNU General Public Licence,
# either version 2, or version 3 (at your option).

"""Read osc configuration and store it in a dictionary

This module reads and parses ~/.oscrc. The resulting configuration is stored
for later usage in a dictionary named 'config'.
The .oscrc is kept mode 0600, so that it is not publically readable.
This gives no real security for storing passwords.
If in doubt, use your favourite keyring.
Password is stored on ~/.oscrc as bz2 compressed and base64 encoded, so that is fairly
large and not to be recognized or remembered easily by an occasional spectator.

If information is missing, it asks the user questions.

After reading the config, urllib2 is initialized.

The configuration dictionary could look like this:

{'apisrv': 'https://api.opensuse.org/',
 'user': 'joe',
 'api_host_options': {'api.opensuse.org': {'user': 'joe', 'pass': 'secret'},
                      'apitest.opensuse.org': {'user': 'joe', 'pass': 'secret',
                                               'http_headers':(('Host','api.suse.de'),
                                                               ('User','faye'))},
                      'foo.opensuse.org': {'user': 'foo', 'pass': 'foo'}},
 'build-cmd': '/usr/bin/build',
 'build-root': '/abuild/oscbuild-%(repo)s-%(arch)s',
 'packagecachedir': '/var/cache/osbuild',
 'su-wrapper': 'sudo',
 }

"""

import OscConfigParser
from osc import oscerr
from oscsslexcp import NoSecureSSLError
import os

GENERIC_KEYRING = False
GNOME_KEYRING = False

try:
    import keyring
    GENERIC_KEYRING = True

except:
    try:
        import gobject
        gobject.set_application_name('osc')
        import gnomekeyring
        if os.environ['GNOME_DESKTOP_SESSION_ID']:
            # otherwise gnome keyring bindings spit out errors, when you have
            # it installed, but you are not under gnome
            # (even though hundreds of gnome-keyring daemons got started in parallel)
            # another option would be to support kwallet here
            GNOME_KEYRING = gnomekeyring.is_available()
    except:
        pass

DEFAULTS = { 'apiurl': 'https://api.opensuse.org',
             'user': 'your_username',
             'pass': 'your_password',
             'passx': '',
             'packagecachedir': '/var/tmp/osbuild-packagecache',
             'su-wrapper': 'su -c',

             # build type settings
             'build-cmd': '/usr/bin/build',
             'build-type': '', # may be empty for chroot, kvm or xen
             'build-root': '/var/tmp/build-root',
             'build-uid': '', # use the default provided by build
             'build-device': '', # required for VM builds
             'build-memory': '',# required for VM builds
             'build-swap': '',  # optional for VM builds
             'build-vmdisk-rootsize': '', # optional for VM builds
             'build-vmdisk-swapsize': '', # optional for VM builds

             'build-jobs': os.sysconf('SC_NPROCESSORS_ONLN'), # compile with N jobs
             'builtin_signature_check': '1', # by default use builtin check for verify pkgs
             'icecream': '0',

             'debug': '0',
             'http_debug': '0',
             'http_full_debug': '0',
             'verbose': '1',
             'traceback': '0',
             'post_mortem': '0',
             'use_keyring': '1',
             'gnome_keyring': '1',
             'cookiejar': '~/.osc_cookiejar',
             # fallback for osc build option --no-verify
             'no_verify': '0',
             # enable project tracking by default
             'do_package_tracking': '1',
             # default for osc build
             'extra-pkgs': '',
             # default repository
             'build_repository': 'openSUSE_Factory',
             # default project for branch or bco
             'getpac_default_project': 'openSUSE:Factory',
             # alternate filesystem layout: have multiple subdirs, where colons were.
             'checkout_no_colon': '0',
             # local files to ignore with status, addremove, ....
             # local files to ignore with status, addremove, ....
             'exclude_glob': '.osc CVS .svn .* _linkerror *~ #*# *.orig *.bak *.changes.vctmp.*',
             # keep passwords in plaintext. If you see this comment, your osc
             # already uses the encrypted password, and only keeps them in plain text
             # for backwards compatibility. Default will change to 0 in future releases.
             'plaintext_passwd': '1',
             # limit the age of requests shown with 'osc req list'.
             # this is a default only, can be overridden by 'osc req list -D NNN'
             # Use 0 for unlimted.
             'request_list_days': 0,
             # check for unversioned/removed files before commit
             'check_filelist': '1',
             # External scripts to validate sources, esp before commit. This is a directory
             'source_validator_directory': '/usr/lib/osc/source_validators',
             # check for pending requests after executing an action (e.g. checkout, update, commit)
             'check_for_request_on_action': '0',
             # what to do with the source package if the submitrequest has been accepted
             'submitrequest_on_accept_action': '',
             'request_show_interactive': '0',
             'submitrequest_accepted_template': '',
             'submitrequest_declined_template': '',
             'linkcontrol': '0',

             # Maintenance defaults to OBS instance defaults
             'maintained_attribute': 'OBS:Maintained',
             'maintained_update_project_attribute': 'OBS:UpdateProject',
             'show_download_progress': '0',
}

# being global to this module, this dict can be accessed from outside
# it will hold the parsed configuration
config = DEFAULTS.copy()

boolean_opts = ['debug', 'do_package_tracking', 'http_debug', 'post_mortem', 'traceback', 'check_filelist', 'plaintext_passwd',
    'checkout_no_colon', 'check_for_request_on_action', 'linkcontrol', 'show_download_progress', 'request_show_interactive',
    'use_keyring', 'gnome_keyring', 'no_verify', 'builtin_signature_check', 'http_full_debug']

api_host_options = ['user', 'pass', 'passx', 'aliases', 'http_headers', 'email', 'sslcertck', 'cafile', 'capath', 'trusted_prj']

new_conf_template = """
[general]

# URL to access API server, e.g. %(apiurl)s
# you also need a section [%(apiurl)s] with the credentials
apiurl = %(apiurl)s

# Downloaded packages are cached here. Must be writable by you.
#packagecachedir = %(packagecachedir)s

# Wrapper to call build as root (sudo, su -, ...)
#su-wrapper = %(su-wrapper)s

# rootdir to setup the chroot environment
# can contain %%(repo)s, %%(arch)s, %%(project)s and %%(package)s for replacement, e.g.
# /srv/oscbuild/%%(repo)s-%%(arch)s or
# /srv/oscbuild/%%(repo)s-%%(arch)s-%%(project)s-%%(package)s
#build-root = %(build-root)s

# compile with N jobs (default: "getconf _NPROCESSORS_ONLN")
#build-jobs = N

# build-type to use - values can be (depending on the capabilities of the 'build' script)
# empty    -  chroot build
# kvm      -  kvm VM build  (needs build-device, build-swap, build-memory)
# xen      -  xen VM build  (needs build-device, build-swap, build-memory)
#   experimental:
#     qemu -  qemu VM build
#     lxc  -  lxc build
#build-type =

# build-device is the disk-image file to use as root for VM builds
# e.g. /var/tmp/FILE.root
#build-device = /var/tmp/FILE.root

# build-swap is the disk-image to use as swap for VM builds
# e.g. /var/tmp/FILE.swap
#build-swap = /var/tmp/FILE.swap

# build-memory is the amount of memory used in the VM
# value in MB - e.g. 512
#build-memory = 512

# build-vmdisk-rootsize is the size of the disk-image used as root in a VM build
# values in MB - e.g. 4096
#build-vmdisk-rootsize = 4096

# build-vmdisk-swapsize is the size of the disk-image used as swap in a VM build
# values in MB - e.g. 1024
#build-vmdisk-swapsize = 1024

# Numeric uid:gid to assign to the "abuild" user in the build-root
# or "caller" to use the current users uid:gid
# This is convenient when sharing the buildroot with ordinary userids
# on the host.
# This should not be 0
# build-uid =

# extra packages to install when building packages locally (osc build)
# this corresponds to osc build's -x option and can be overridden with that
# -x '' can also be given on the command line to override this setting, or
# you can have an empty setting here.
#extra-pkgs = vim gdb strace

# build platform is used if the platform argument is omitted to osc build
#build_repository = %(build_repository)s

# default project for getpac or bco
#getpac_default_project = %(getpac_default_project)s

# alternate filesystem layout: have multiple subdirs, where colons were.
#checkout_no_colon = %(checkout_no_colon)s

# local files to ignore with status, addremove, ....
#exclude_glob = %(exclude_glob)s

# keep passwords in plaintext. If you see this comment, your osc
# already uses the encrypted password, and only keeps them in plain text
# for backwards compatibility. Default will change to 0 in future releases.
# You can remove the plaintext password without harm, if you do not need
# backwards compatibility.
#plaintext_passwd = %(plaintext_passwd)s

# limit the age of requests shown with 'osc req list'.
# this is a default only, can be overridden by 'osc req list -D NNN'
# Use 0 for unlimted.
#request_list_days = %(request_list_days)s

# show info useful for debugging
#debug = 1

# show HTTP traffic useful for debugging
#http_debug = 1

# Skip signature verification of packages used for build.
#no_verify = 1

# jump into the debugger in case of errors
#post_mortem = 1

# print call traces in case of errors
#traceback = 1

# use KDE/Gnome/MacOS/Windows keyring for credentials if available
#use_keyring = 1

# check for unversioned/removed files before commit
#check_filelist = 1

# check for pending requests after executing an action (e.g. checkout, update, commit)
#check_for_request_on_action = 0

# what to do with the source package if the submitrequest has been accepted. If
# nothing is specified the API default is used
#submitrequest_on_accept_action = cleanup|update|noupdate

# template for an accepted submitrequest
#submitrequest_accepted_template = Hi %%(who)s,\\nthanks for working on %%(dst_project)s/%%(dst_package)s. SR %%(reqid)s has been accepted.\\n\\nYour maintainers

# template for a declined submitrequest
#submitrequest_declined_template = Hi %%(who)s,\\nsorry your SR %%(reqid)s for %%(dst_project)s/%%(dst_package)s has been declined because ...

#review requests interactively (default: off)
#request_show_review = 1

# Directory with executables to validate sources, esp before committing
#source_validator_directory = /usr/lib/osc/source_validators

[%(apiurl)s]
user = %(user)s
pass = %(pass)s
passx = %(passx)s
# set aliases for this apiurl
# aliases = foo, bar
# email used in .changes, unless the one from osc meta prj <user> will be used
# email =
# additional headers to pass to a request, e.g. for special authentication
#http_headers = Host: foofoobar,
#       User: mumblegack
# Force using of keyring for this API
#keyring = 1
"""


account_not_configured_text ="""
Your user account / password are not configured yet.
You will be asked for them below, and they will be stored in
%s for future use.
"""

config_incomplete_text = """

Your configuration file %s is not complete.
Make sure that it has a [general] section.
(You can copy&paste the below. Some commented defaults are shown.)

"""

config_missing_apiurl_text = """
the apiurl \'%s\' does not exist in the config file. Please enter
your credentials for this apiurl.
"""

cookiejar = None

def parse_apisrv_url(scheme, apisrv):
    import urlparse
    if apisrv.startswith('http://') or apisrv.startswith('https://'):
        return urlparse.urlsplit(apisrv)[0:2]
    elif scheme != None:
        # the split/join is needed to get a proper url (e.g. without a trailing slash)
        return urlparse.urlsplit(urljoin(scheme, apisrv))[0:2]
    else:
        from urllib2 import URLError
        msg = 'invalid apiurl \'%s\' (specify the protocol (http:// or https://))' % apisrv
        raise URLError(msg)

def urljoin(scheme, apisrv):
    return '://'.join([scheme, apisrv])

def is_known_apiurl(url):
    """returns true if url is a known apiurl"""
    apiurl = urljoin(*parse_apisrv_url(None, url))
    return config['api_host_options'].has_key(apiurl)

def get_apiurl_api_host_options(apiurl):
    """
    Returns all apihost specific options for the given apiurl, None if
    no such specific optiosn exist.
    """
    # FIXME: in A Better World (tm) there was a config object which
    # knows this instead of having to extract it from a url where it
    # had been mingled into before.  But this works fine for now.

    apiurl = urljoin(*parse_apisrv_url(None, apiurl))
    if is_known_apiurl(apiurl):
        return config['api_host_options'][apiurl]
    raise oscerr.ConfigMissingApiurl('missing credentials for apiurl: \'%s\'' % apiurl,
                                     '', apiurl)

def get_apiurl_usr(apiurl):
    """
    returns the user for this host - if this host does not exist in the
    internal api_host_options the default user is returned.
    """
    # FIXME: maybe there should be defaults not just for the user but
    # for all apihost specific options.  The ConfigParser class
    # actually even does this but for some reason we don't use it
    # (yet?).

    import sys
    try:
        return get_apiurl_api_host_options(apiurl)['user']
    except KeyError:
        print >>sys.stderr, 'no specific section found in config file for host of [\'%s\'] - using default user: \'%s\'' \
            % (apiurl, config['user'])
        return config['user']

# workaround m2crypto issue:
# if multiple SSL.Context objects are created
# m2crypto only uses the last object which was created.
# So we need to build a new opener everytime we switch the
# apiurl (because different apiurls may have different
# cafile/capath locations)
def _build_opener(url):
    from osc.core import __version__
    import urllib2
    import sys
    global config
    apiurl = urljoin(*parse_apisrv_url(None, url))
    if not _build_opener.__dict__.has_key('last_opener'):
        _build_opener.last_opener = (None, None)
    if apiurl == _build_opener.last_opener[0]:
        return _build_opener.last_opener[1]

    # workaround for http://bugs.python.org/issue9639
    authhandler_class = urllib2.HTTPBasicAuthHandler
    if sys.version_info >= (2, 6, 6) and sys.version_info < (2, 7, 1) \
        and not 'reset_retry_count' in dir(urllib2.HTTPBasicAuthHandler):
        print >>sys.stderr, 'warning: your urllib2 version seems to be broken. ' \
            'Using a workaround for http://bugs.python.org/issue9639'
        class OscHTTPBasicAuthHandler(urllib2.HTTPBasicAuthHandler):
            def http_error_401(self, *args):
                response = urllib2.HTTPBasicAuthHandler.http_error_401(self, *args)
                self.retried = 0
                return response

        authhandler_class = OscHTTPBasicAuthHandler
    elif sys.version_info >= (2, 6, 5) and sys.version_info < (2, 6, 6):
        # workaround for broken urllib2 in python 2.6.5: wrong credentials
        # lead to an infinite recursion
        class OscHTTPBasicAuthHandler(urllib2.HTTPBasicAuthHandler):
            def retry_http_basic_auth(self, host, req, realm):
                # don't retry if auth failed
                if req.get_header(self.auth_header, None) is not None:
                    return None
                return urllib2.HTTPBasicAuthHandler.retry_http_basic_auth(self, host, req, realm)

        authhandler_class = OscHTTPBasicAuthHandler

    options = config['api_host_options'][apiurl]
    # with None as first argument, it will always use this username/password
    # combination for urls for which arg2 (apisrv) is a super-url
    authhandler = authhandler_class( \
        urllib2.HTTPPasswordMgrWithDefaultRealm())
    authhandler.add_password(None, apiurl, options['user'], options['pass'])

    if options['sslcertck']:
        try:
            import oscssl
            from M2Crypto import m2urllib2
        except ImportError, e:
            print e
            raise NoSecureSSLError('M2Crypto is needed to access %s in a secure way.\nPlease install python-m2crypto.' % apiurl)

        cafile = options.get('cafile', None)
        capath = options.get('capath', None)
        if not cafile and not capath:
            for i in ['/etc/pki/tls/cert.pem', '/etc/ssl/certs' ]:
                if os.path.isfile(i):
                    cafile = i
                    break
                elif os.path.isdir(i):
                    capath = i
                    break
        ctx = oscssl.mySSLContext()
        if ctx.load_verify_locations(capath=capath, cafile=cafile) != 1: raise Exception('No CA certificates found')
        opener = m2urllib2.build_opener(ctx, oscssl.myHTTPSHandler(ssl_context = ctx, appname = 'osc'), urllib2.HTTPCookieProcessor(cookiejar), authhandler)
    else:
        import sys
        print >>sys.stderr, "WARNING: SSL certificate checks disabled. Connection is insecure!\n"
        opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cookiejar), authhandler)
    opener.addheaders = [('User-agent', 'osc/%s' % __version__)]
    _build_opener.last_opener = (apiurl, opener)
    return opener

def init_basicauth(config):
    """initialize urllib2 with the credentials for Basic Authentication"""

    import cookielib
    import urllib2
    import sys
    import httplib
    def filterhdrs(meth, ishdr, *hdrs):
        import re
        import sys
        import StringIO
        # this is so ugly but httplib doesn't use
        # a logger object or such
        def new_method(*args, **kwargs):
            stdout = sys.stdout
            sys.stdout = StringIO.StringIO()
            meth(*args, **kwargs)
            hdr = sys.stdout.getvalue()
            sys.stdout = stdout
            for i in hdrs:
                if ishdr:
                    hdr = re.sub(r'%s:[^\\r]*\\r\\n' % i, '', hdr)
                else:
                    hdr = re.sub(i, '', hdr)
            sys.stdout.write(hdr)
        new_method.__name__ = meth.__name__
        return new_method

    if config['http_debug'] and not config['http_full_debug']:
        httplib.HTTPConnection.send = filterhdrs(httplib.HTTPConnection.send, True, 'Cookie', 'Authorization')
        httplib.HTTPResponse.begin = filterhdrs(httplib.HTTPResponse.begin, False, 'header: Set-Cookie.*\n')

    if sys.version_info < (2, 6):
        # HTTPS proxy is not supported in old urllib2. It only leads to an error
        # or, at best, a warning.
        if 'https_proxy' in os.environ:
            del os.environ['https_proxy']
        if 'HTTPS_PROXY' in os.environ:
            del os.environ['HTTPS_PROXY']

    if config['http_debug']:
        # brute force
        def urllib2_debug_init(self, debuglevel=0):
            self._debuglevel = 1
        urllib2.AbstractHTTPHandler.__init__ = urllib2_debug_init

    cookie_file = os.path.expanduser(config['cookiejar'])
    global cookiejar
    cookiejar = cookielib.LWPCookieJar(cookie_file)
    try:
        cookiejar.load(ignore_discard=True)
    except IOError:
        try:
            open(cookie_file, 'w').close()
            os.chmod(cookie_file, 0600)
        except:
            #print 'Unable to create cookiejar file: \'%s\'. Using RAM-based cookies.' % cookie_file
            cookiejar = cookielib.CookieJar()


def get_configParser(conffile=None, force_read=False):
    """
    Returns an ConfigParser() object. After its first invocation the
    ConfigParser object is stored in a method attribute and this attribute
    is returned unless you pass force_read=True.
    """
    conffile = conffile or os.environ.get('OSC_CONFIG', '~/.oscrc')
    conffile = os.path.expanduser(conffile)
    if not get_configParser.__dict__.has_key('conffile'):
        get_configParser.conffile = conffile
    if force_read or not get_configParser.__dict__.has_key('cp') or conffile != get_configParser.conffile:
        get_configParser.cp = OscConfigParser.OscConfigParser(DEFAULTS)
        get_configParser.cp.read(conffile)
        get_configParser.conffile = conffile
    return get_configParser.cp

def config_set_option(section, opt, val=None, delete=False, update=True, **kwargs):
    """
    Sets a config option. If val is not specified the current/default value is
    returned. If val is specified, opt is set to val and the new value is returned.
    If an option was modified get_config is called with **kwargs unless update is set
    to False (override_conffile defaults to config['conffile']).
    If val is not specified and delete is True then the option is removed from the
    config/reset to the default value.
    """
    def write_config(fname, cp):
        """write new configfile in a safe way"""
        try:
            f = open(fname + '.new', 'w')
            cp.write(f, comments=True)
            f.close()
            os.rename(fname + '.new', fname)
        except:
            if os.path.exists(fname + '.new'):
                os.unlink(fname + '.new')
            raise

    cp = get_configParser(config['conffile'])
    # don't allow "internal" options
    general_opts = [i for i in DEFAULTS.keys() if not i in ['user', 'pass', 'passx']]
    if section != 'general':
        section = config['apiurl_aliases'].get(section, section)
        scheme, host = \
            parse_apisrv_url(config.get('scheme', 'https'), section)
        section = urljoin(scheme, host)

    sections = {}
    for url in cp.sections():
        if url == 'general':
            sections[url] = url
        else:
            scheme, host = \
                parse_apisrv_url(config.get('scheme', 'https'), url)
            apiurl = urljoin(scheme, host)
            sections[apiurl] = url

    section = sections.get(section.rstrip('/'), section)
    if not section in cp.sections():
        raise oscerr.ConfigError('unknown section \'%s\'' % section, config['conffile'])
    if section == 'general' and not opt in general_opts or \
       section != 'general' and not opt in api_host_options:
        raise oscerr.ConfigError('unknown config option \'%s\'' % opt, config['conffile'])
    run = False
    if val:
        cp.set(section, opt, val)
        write_config(config['conffile'], cp)
        run = True
    elif delete and cp.has_option(section, opt):
        cp.remove_option(section, opt)
        write_config(config['conffile'], cp)
        run = True
    if run and update:
        kw = {'override_conffile': config['conffile']}
        kw.update(kwargs)
        get_config(**kw)
    if cp.has_option(section, opt):
        return (opt, cp.get(section, opt, raw=True))
    return (opt, None)

def write_initial_config(conffile, entries, custom_template = ''):
    """
    write osc's intial configuration file. entries is a dict which contains values
    for the config file (e.g. { 'user' : 'username', 'pass' : 'password' } ).
    custom_template is an optional configuration template.
    """
    import StringIO, sys, base64
    conf_template = custom_template or new_conf_template
    config = DEFAULTS.copy()
    config.update(entries)
    config['passx'] = base64.b64encode(config['pass'].encode('bz2'))
    # at this point use_keyring and gnome_keyring are str objects
    if config['use_keyring'] == '1' and GENERIC_KEYRING:
        protocol, host = \
            parse_apisrv_url(None, config['apiurl'])
        keyring.set_password(host, config['user'], config['pass'])
        config['pass'] = ''
        config['passx'] = ''
    elif config['gnome_keyring'] == '1' and GNOME_KEYRING:
        protocol, host = \
            parse_apisrv_url(None, config['apiurl'])
        gnomekeyring.set_network_password_sync(
            user = config['user'],
            password = config['pass'],
            protocol = protocol,
            server = host)
        config['user'] = ''
        config['pass'] = ''
        config['passx'] = ''
    if not config['plaintext_passwd']:
        config['pass'] = ''
    sio = StringIO.StringIO(conf_template.strip() % config)
    cp = OscConfigParser.OscConfigParser(DEFAULTS)
    cp.readfp(sio)

    file = None
    try:
        file = open(conffile, 'w')
    except IOError, e:
        raise oscerr.OscIOError(e, 'cannot open configfile \'%s\'' % conffile)
    try:
        try:
            os.chmod(conffile, 0600)
            cp.write(file, True)
        except IOError, e:
            raise oscerr.OscIOError(e, 'cannot write configfile \'s\'' % conffile)
    finally:
        if file: file.close()

def add_section(filename, url, user, passwd):
    """
    Add a section to config file for new api url.
    """
    import base64
    global config
    cp = get_configParser(filename)
    try:
        cp.add_section(url)
    except OscConfigParser.ConfigParser.DuplicateSectionError:
        # Section might have existed, but was empty
        pass
    if config['use_keyring'] and GENERIC_KEYRING:
        protocol, host = \
            parse_apisrv_url(None, url)
        keyring.set_password(host, user, passwd)
        cp.set(url, 'keyring', '1')
        cp.set(url, 'user', user)
        cp.remove_option(url, 'pass')
        cp.remove_option(url, 'passx')
    elif config['gnome_keyring'] and GNOME_KEYRING:
        protocol, host = \
            parse_apisrv_url(None, url)
        gnomekeyring.set_network_password_sync(
            user = user,
            password = passwd,
            protocol = protocol,
            server = host)
        cp.set(url, 'keyring', '1')
        cp.remove_option(url, 'pass')
        cp.remove_option(url, 'passx')
    else:
        cp.set(url, 'user', user)
        if not config['plaintext_passwd']:
            cp.remove_option(url, 'pass')
        cp.set(url, 'passx', base64.b64encode(passwd.encode('bz2')))
    file = open(filename, 'w')
    cp.write(file, True)
    if file: file.close()


def get_config(override_conffile = None,
               override_apiurl = None,
               override_debug = None,
               override_http_debug = None,
               override_http_full_debug = None,
               override_traceback = None,
               override_post_mortem = None,
               override_no_keyring = None,
               override_no_gnome_keyring = None,
               override_verbose = None):
    """do the actual work (see module documentation)"""
    import sys
    import re
    global config

    conffile = override_conffile or os.environ.get('OSC_CONFIG', '~/.oscrc')
    conffile = os.path.expanduser(conffile)

    if not os.path.exists(conffile):
        raise oscerr.NoConfigfile(conffile, \
                                  account_not_configured_text % conffile)

    # okay, we made sure that .oscrc exists

    # make sure it is not world readable, it may contain a password.
    os.chmod(conffile, 0600)

    cp = get_configParser(conffile)

    if not cp.has_section('general'):
        # FIXME: it might be sufficient to just assume defaults?
        msg = config_incomplete_text % conffile
        msg += new_conf_template % DEFAULTS
        raise oscerr.ConfigError(msg, conffile)

    config = dict(cp.items('general', raw=1))
    config['conffile'] = conffile

    for i in boolean_opts:
        try:
            config[i] = cp.getboolean('general', i)
        except ValueError, e:
            raise oscerr.ConfigError('cannot parse \'%s\' setting: ' % i + str(e), conffile)

    config['packagecachedir'] = os.path.expanduser(config['packagecachedir'])
    config['exclude_glob'] = config['exclude_glob'].split()

    re_clist = re.compile('[, ]+')
    config['extra-pkgs'] = [ i.strip() for i in re_clist.split(config['extra-pkgs'].strip()) if i ]

    # collect the usernames, passwords and additional options for each api host
    api_host_options = {}

    # Regexp to split extra http headers into a dictionary
    # the text to be matched looks essentially looks this:
    # "Attribute1: value1, Attribute2: value2, ..."
    # there may be arbitray leading and intermitting whitespace.
    # the following regexp does _not_ support quoted commas within the value.
    http_header_regexp = re.compile(r"\s*(.*?)\s*:\s*(.*?)\s*(?:,\s*|\Z)")

    # override values which we were called with
    # This needs to be done before processing API sections as it might be already used there
    if override_no_keyring:
        config['use_keyring'] = False
    if override_no_gnome_keyring:
        config['gnome_keyring'] = False

    aliases = {}
    for url in [ x for x in cp.sections() if x != 'general' ]:
        # backward compatiblity
        scheme, host = \
            parse_apisrv_url(config.get('scheme', 'https'), url)
        apiurl = urljoin(scheme, host)
        user = None
        if config['use_keyring'] and GENERIC_KEYRING:
            try:
                # Read from keyring lib if available
                user = cp.get(url, 'user', raw=True)
                password = keyring.get_password(host, user)
            except:
                # Fallback to file based auth.
                pass
        elif config['gnome_keyring'] and GNOME_KEYRING:
            # Read from gnome keyring if available
            try:
                gk_data = gnomekeyring.find_network_password_sync(
                    protocol = scheme,
                    server = host)
                password = gk_data[0]['password']
                user = gk_data[0]['user']
            except gnomekeyring.NoMatchError:
                # Fallback to file based auth.
                pass
        # Read credentials from config
        if user is None:
            #FIXME: this could actually be the ideal spot to take defaults
            #from the general section.
            user         = cp.get(url, 'user', raw=True) # need to set raw to prevent '%' expansion
            password     = cp.get(url, 'pass', raw=True) # especially on password!
            passwordx    = cp.get(url, 'passx', raw=True) # especially on password!
            if password is None or password == 'your_password':
                try:
                    password = passwordx.decode('base64').decode('bz2')
                except:
                    print "%s: no credentials known" % url
                    password = 'your_password'
            elif password != passwordx.decode('base64').decode('bz2'):
                if not passwordx:
                    # passx not present
                    print '%s: rewriting from plain pass to encoded pass\n' % url
                else:
                    print '%s: pass and passx mismatch (rewriting from plain pass to encoded pass)\n' % url
                add_section(conffile, url, user, password)

        if cp.has_option(url, 'http_headers'):
            http_headers = cp.get(url, 'http_headers')
            http_headers = http_header_regexp.findall(http_headers)
        else:
            http_headers = []
        if cp.has_option(url, 'aliases'):
            for i in cp.get(url, 'aliases').split(','):
                key = i.strip()
                if key == '':
                    continue
                if aliases.has_key(key):
                    msg = 'duplicate alias entry: \'%s\' is already used for another apiurl' % key
                    raise oscerr.ConfigError(msg, conffile)
                aliases[key] = url

        api_host_options[apiurl] = { 'user': user,
                                     'pass': password,
                                     'http_headers': http_headers}

        optional = ('email', 'sslcertck', 'cafile', 'capath')
        for key in optional:
            if cp.has_option(url, key):
                if key == 'sslcertck':
                    api_host_options[apiurl][key] = cp.getboolean(url, key)
                else:
                    api_host_options[apiurl][key] = cp.get(url, key)

        if not 'sslcertck' in api_host_options[apiurl]:
            api_host_options[apiurl]['sslcertck'] = True

        if scheme == 'http':
            api_host_options[apiurl]['sslcertck'] = False

        if cp.has_option(url, 'trusted_prj'):
            api_host_options[apiurl]['trusted_prj'] = cp.get(url, 'trusted_prj').split(' ')
        else:
            api_host_options[apiurl]['trusted_prj'] = []

    # add the auth data we collected to the config dict
    config['api_host_options'] = api_host_options
    config['apiurl_aliases'] = aliases

    apiurl = aliases.get(config['apiurl'], config['apiurl'])
    config['apiurl'] = urljoin(*parse_apisrv_url(None, apiurl))
    # backward compatibility
    if config.has_key('apisrv'):
        apisrv = config['apisrv'].lstrip('http://')
        apisrv = apisrv.lstrip('https://')
        scheme = config.get('scheme', 'https')
        config['apiurl'] = urljoin(scheme, apisrv)
    if config.has_key('apisrv') or config.has_key('scheme'):
        print >>sys.stderr, 'Warning: Use of the \'scheme\' or \'apisrv\' in ~/.oscrc is deprecated!\n' \
                            'Warning: See README for migration details.'
    if config.has_key('build_platform'):
        print >>sys.stderr, 'Warning: Use of \'build_platform\' config option is deprecated! (use \'build_repository\' instead)'
        config['build_repository'] = config['build_platform']

    config['verbose'] = int(config['verbose'])
    # override values which we were called with
    if override_verbose:
        config['verbose'] = override_verbose + 1

    if override_debug:
        config['debug'] = override_debug
    if override_http_debug:
        config['http_debug'] = override_http_debug
    if override_http_full_debug:
        config['http_debug'] = override_http_full_debug or config['http_debug']
        config['http_full_debug'] = override_http_full_debug
    if override_traceback:
        config['traceback'] = override_traceback
    if override_post_mortem:
        config['post_mortem'] = override_post_mortem
    if override_apiurl:
        apiurl = aliases.get(override_apiurl, override_apiurl)
        # check if apiurl is a valid url
        config['apiurl'] = urljoin(*parse_apisrv_url(None, apiurl))

    # XXX unless config['user'] goes away (and is replaced with a handy function, or
    # config becomes an object, even better), set the global 'user' here as well,
    # provided that there _are_ credentials for the chosen apiurl:
    try:
        config['user'] = get_apiurl_usr(config['apiurl'])
    except oscerr.ConfigMissingApiurl, e:
        e.msg = config_missing_apiurl_text % config['apiurl']
        e.file = conffile
        raise e

    # finally, initialize urllib2 for to use the credentials for Basic Authentication
    init_basicauth(config)

# vim: sw=4 et