# Volatility
#
# 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 

"""
@author:       Joe Sylve
@license:      GNU General Public License 2.0 or later
@contact:      joe.sylve@gmail.com
@organization: 504ENSICS Labs
"""

import volatility.obj as obj
import volatility.debug as debug
import volatility.plugins.linux.common as linux_common


class linux_check_tty(linux_common.AbstractLinuxCommand):
    """Checks tty devices for hooks"""

    def calculate(self):
        linux_common.set_plugin_members(self)

        tty_addr = self.get_profile_symbol("tty_drivers")
        
        if not tty_addr:
            debug.error("Symbol tty_drivers not found in kernel")
                        
        drivers = obj.Object("list_head", offset = tty_addr, vm = self.addr_space)
        
        for tty in drivers.list_of_type("tty_driver", "tty_drivers"):
            name = tty.name.dereference_as("String", length = linux_common.MAX_STRING_LENGTH)
            
            ttys = obj.Object("Array", targetType="Pointer", vm = self.addr_space, offset = tty.ttys, count = tty.num)
            for tty_dev in ttys:
                if tty_dev == 0:
                    continue
                
                tty_dev = tty_dev.dereference_as("tty_struct")
                name = tty_dev.name
                recv_buf = tty_dev.ldisc.ops.receive_buf
                
                yield (name, recv_buf)

    def render_text(self, outfd, data):
        symbol_cache = {}
        self.table_header(outfd, [("Name", "<16"), ("Address", "[addrpad]"), ("Symbol", "<30")])
        for name, call_addr in data:
        
            if symbol_cache.has_key(call_addr):
                sym_name = symbol_cache[call_addr]
            else:
                sym_name = self.profile.get_symbol_by_address("kernel", call_addr)
                if not sym_name:
                    sym_name = "HOOKED"
                    
                symbol_cache[call_addr] = sym_name

            self.table_row(outfd, name, call_addr, sym_name)