/usr/share/system-config-printer/troubleshoot/CheckUSBPermissions.py is in system-config-printer-gnome 1.3.8+20120201-0ubuntu8.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 | #!/usr/bin/python
## Printing troubleshooter
## Copyright (C) 2008, 2009, 2010 Red Hat, Inc.
## Authors:
##  Tim Waugh <twaugh@redhat.com>
## This program 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 2 of the License, or
## (at your option) any later version.
## This program 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 this program; if not, write to the Free Software
## Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
import glob
import os
import subprocess
from timedops import TimedSubprocess
import urllib
from base import *
class CheckUSBPermissions(Question):
    def __init__ (self, troubleshooter):
        Question.__init__ (self, troubleshooter, "Check USB permissions")
        troubleshooter.new_page (gtk.Label (), self)
    def display (self):
        self.answers = {}
        answers = self.troubleshooter.answers
        if answers['cups_queue_listed']:
            if answers['is_cups_class']:
                return False
            cups_printer_dict = answers['cups_printer_dict']
            device_uri = cups_printer_dict['device-uri']
        elif answers.get ('cups_device_listed', False):
            device_uri = answers['cups_device_uri']
        else:
            return False
        (scheme, rest) = urllib.splittype (device_uri)
        if scheme not in ['hp', 'hpfax', 'usb', 'hal']:
            return False
        LSUSB = "/sbin/lsusb"
        if not os.access (LSUSB, os.X_OK):
            return False
        GETFACL = "/usr/bin/getfacl"
        if not os.access (GETFACL, os.X_OK):
            return False
        new_environ = os.environ.copy()
        new_environ['LC_ALL'] = "C"
        # Run lsusb
        parent = self.troubleshooter.get_window ()
        try:
            self.op = TimedSubprocess (parent=parent,
                                       args=[LSUSB, "-v"],
                                       close_fds=True,
                                       env=new_environ,
                                       stdin=file("/dev/null"),
                                       stdout=subprocess.PIPE,
                                       stderr=subprocess.PIPE)
            (lsusb_stdout, lsusb_stderr, result) = self.op.run ()
        except:
            # Problem executing command.
            return False
        # Now parse it.
        dev_by_id = {}
        this_dev = None
        for line in lsusb_stdout:
            if (this_dev != None and
                ((line.find ("bInterfaceClass") != -1 and
                  line.find ("7 Printer") != -1) or
                 (line.find ("bInterfaceSubClass") != -1 and
                  line.find ("1 Printer") != -1))):
                mfr = dev_by_id.get (this_mfr_id, {})
                mdl = mfr.get (this_mdl_id, [])
                mdl.append (this_dev)
                mfr[this_mdl_id] = mdl
                dev_by_id[this_mfr_id] = mfr
                this_dev = None
                continue
            separators = [ ('Bus ', 3),
                           (' Device ', 3),
                           (': ID ', 4),
                           (':', 4),
                           (' ', -1)]
            fields = []
            i = 0
            p = line
            while i < len (separators):
                (sep, length) = separators[i]
                if not p.startswith (sep):
                    break
                start = len (sep)
                if length == -1:
                    end = len (p)
                    fields.append (p[start:])
                else:
                    end = start + length
                    fields.append (p[start:end])
                p = p[end:]
                i += 1
            if i < len (separators):
                continue
            if not scheme.startswith ('hp') and fields[2] != '03f0':
                # Skip non-HP printers if we know we're using HPLIP.
                continue
            this_dev = { 'bus': fields[0],
                         'dev': fields[1],
                         'name': fields[4],
                         'full': line }
            this_mfr_id = fields[2]
            this_mdl_id = fields[3]
        infos = {}
        paths = []
        if not scheme.startswith ('hp'):
            paths.extend (glob.glob ("/dev/usb/lp?"))
        for mfr_id, mdls in dev_by_id.iteritems ():
            for mdl_id, devs in mdls.iteritems ():
                for dev in devs:
                    path = "/dev/bus/usb/%s/%s" % (dev['bus'], dev['dev'])
                    paths.append (path)
                    infos[path] = dev['full']
        perms = []
        for path in paths:
            try:
                self.op = TimedSubprocess (parent=parent,
                                           args=[GETFACL, path],
                                           close_fds=True,
                                           env=new_environ,
                                           stdin=file("/dev/null"),
                                           stdout=subprocess.PIPE,
                                           stderr=subprocess.PIPE)
                (getfacl_stdout, getfacl_stderr, result) = self.op.run ()
                output = filter (lambda x: len (x) > 0, getfacl_stdout)
            except:
                # Problem executing command.
                output = []
            info = infos.get (path, path)
            perms.append ((info, output))
        self.answers['getfacl_output'] = perms
        # Don't actually display anything, just collect information.
        return False
    def collect_answer (self):
        return self.answers
    def cancel_operation (self):
        self.op.cancel ()
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