/usr/sbin/tftpd is in cobbler 2.4.1-0ubuntu2.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
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"""
SYNOPSIS
tftpd.py [-h,--help] [-v,--verbose] [-d,--debug] [--version]
[--port=<port>(69)]
DESCRIPTION
A python, cobbler integrated TFTP server. It is suitable to call via
xinetd, or as a stand-alone daemon. If called via xinetd, it will run,
handling requests, until it has been idle for at least 30 seconds, and
will then exit.
This server queries cobbler for information about hosts that make requests,
and will instantiate template files from the materialized hosts'
'fetchable_files' attribute.
EXIT STATUS
AUTHOR
Douglas Kilpatrick <kilpatds@oppositelock.org>
LICENSE
This script is in the public domain, free from copyrights or restrictions
VERSION
0.5
TODO
Requirement: retransmit
Requirement: Ignore stale retrainsmits
Security: only return files that are o+r
Security: support hosts.allow/deny
Security: Make absolute path support optional, and default off
Feature: support blksize2 (blksize, limited to powers of 2)
Feature: support utimeout (timeout, in ms)
"""
VERSION=0.5
import sys, os, stat, errno, time, optparse, re, socket, pwd, traceback
import logging, logging.handlers
import xmlrpclib
from collections import deque
from fnmatch import fnmatch
from cobbler.utils import local_get_cobbler_api_url, tftpboot_location
import tornado.ioloop as ioloop
import cobbler.templar
import Cheetah # need exception types
from struct import *;
from subprocess import *;
#import functools
# Data/Defines
TFTP_OPCODE_RRQ = 1
TFTP_OPCODE_DATA = 3
TFTP_OPCODE_ACK = 4
TFTP_OPCODE_ERROR = 5
TFTP_OPCODE_OACK = 6
COBBLER_HANDLE = xmlrpclib.Server(local_get_cobbler_api_url())
OPTIONS = {
"port" : "69",
"timeout" : 10,
"min_timeout": 1,
"max_timeout": 255,
"blksize" : 512, # that's the default, required
"max_blksize": 1428, # MTU - overhead
"min_blksize": 512, # the default is small enough already
"retries" : 4,
"verbose" : False,
"debug" : False,
"idle" : 0, # how long to stick around: 0: unlimited
"idle_timer" : None,
"cache" : True, # 'cache-time' = 300
"cache-time" : 5 * 300,
"neg-cache-time" : 10,
"active" : 0,
"prefix" : tftpboot_location(),
"logger" : "stream",
"file_cmd" : "/usr/bin/file",
"user" : "nobody",
# the well known socket. needs to be global for timeout
# Using the options hash as a hackaround for python's
# "create a new object at local scope by default" design.
"sock" : None
}
ERRORS = [
'Not defined, see error message (if any)', # 0
'File not found', # 1
'Access violation', # 2
'Disk full or allocation exceeded', # 3
'Illegal TFTP operation', # 4
'Unknown transfer ID', # 5
'File already exists', # 6
'No such user', # 7
'Option negotiation' # 8
]
REQUESTS = None
class RenderedFile:
"""A class to manage rendered files, without changing the logic
of the rest of the TFTP server. It replaces the file object
via duck typing, and feeds out sections of the saved string
as required"""
def __init__(self, data=""):
"""Provide the string to be served out as an argument to the
constructor. The data object needs to support slices."""
self.data = data
self.offset = 0
def seek(self,bytes):
"""Only the two-argument version of seek (SEEK_SET) is currently
supported"""
self.offset = bytes
def read(self,size):
"""Returns <size> bytes relative to the current offset."""
end = self.offset + size
return self.data[self.offset:end]
class Packet:
"""Represents a packet received (or sent?) from a tftp client.
Is a base class that is intended to be overridden.
The main use cases are "I got a packet, parse it", but
I'm also keeping the "how to write a packet of type X"
in the same class to keep the relevant code snippets close
to each other.
Any strings that control behavior (mode, rfc2347 options) are
case-INsensitive. Filename is allowed to be case sensitive
"""
def __init__(self, data, local_sock, remote_addr):
self.data = data
self.local_sock = local_sock
self.remote_addr = remote_addr
self.opcode, = unpack("!H",data[0:2])
def marshall(self):
raise NotImplementedError("%s: Write marshall method" % repr(self))
def is_error(self):
return False
class RRQPacket(Packet):
"""The RRQ Packet. We only receive those, so this object only
supports the receive use case.
2 bytes string byte String byte
---------------------------------------
DATA | 01 | name | \0 | mode | \0 |
---------------------------------------
string string
----------------------------
rfc2347 | name | \0 | value | \0 | [*]
----------------------------
"""
def __init__(self, data, local_sock, remote_addr):
Packet.__init__(self,data,local_sock,remote_addr)
# opcode already extracted, and unpack is awkward for this
# so pulling out strings by hand
(file,mode,rfc2347str) = data[2:].split('\0',2)
logging.debug("RRQ for file %s(%s) from %s"%(file,mode,remote_addr))
# Ug. Can't come up with a simplier way of doing this
if rfc2347str:
# the "-1" is to trim off the trailing \0
self.req_options = deque(rfc2347str[:-1].split('\0'))
logging.debug("client %s requested options: %s" % (
str(remote_addr),str(rfc2347str.replace('\0',','))))
else:
self.req_options = deque()
self.filename = file
self.mode = mode
def get_request(self,templar):
return Request(file,self.remote_addr,templar)
class DATAPacket(Packet):
"""The DATA packet. We only send these, so this object only
supports the send use case.
2 bytes 2 bytes n bytes
-----------------------------------
DATA | 03 | Block # | Data |
-----------------------------------
"""
def __init__(self, data, blk_num):
self.data = data;
self.blk_num = blk_num;
def marshall(self):
return pack("!HH %ds" % (len(self.data)),
TFTP_OPCODE_DATA, self.blk_num & 0xFFFF ,str(self.data))
class ACKPacket(Packet):
"""The ACK packet. We only receive these.
2 bytes 2 bytes
----------------------
ACK | 04 | Block # |
----------------------
"""
def __init__(self, data, local_sock, remote_addr):
Packet.__init__(self,data,local_sock,remote_addr)
block_number, = unpack("!H",data[2:4])
logging.log(9,"ACK for packet %d from %s"%(block_number,remote_addr))
self.block_number = block_number
def marshall(self):
raise NotImplementedError("We don't send these, we read them")
return pack("!HH", TFTP_OPCODE_ACK, self.block_number)
class ERRORPacket(Packet):
"""The error packet. We could send or receive these.
But we really only handle sending them.
2 bytes 2 bytes string 1 byte
------------------------------------------
ERROR | 05 | ErrorCode | ErrMsg | 0 |
------------------------------------------
"""
def __init__(self, data, local_sock, remote_addr):
Packet.__init__(self,data,local_sock,remote_addr)
self.error_code, = unpack("!h",data[2:4])
self.error_str = data[4:-1]
logging.debug("ERROR %d: %s from %s"%
(self.error_code,self.error_str,remote_addr))
def __init__(self, error_code, error_str):
self.error_code = error_code
self.error_str = error_str
def is_error(self):
return True
def marshall(self):
return pack("!HH %dsB" % (len(self.error_str)),
TFTP_OPCODE_ERROR, self.error_code, self.error_str,0)
class OACKPacket(Packet):
"""The Option Acknowledge (rfc2347) packet. We only send these.
We make an effort to retain name case and order, to aid clients
that depend on either.
2 bytes string 1 byte string 1 byte
----------|--------------------------------
OACK | 06 || name | 0 | value | 0 | [*]
----------|--------------------------------
"""
def __init__(self, rfc2347):
self.opcode = TFTP_OPCODE_OACK
self.options = rfc2347
def marshall(self):
optstr = "\0".join(map(lambda x: str(x), self.options))
return pack("!H %ds c" % (len(optstr)),self.opcode, optstr, '\0')
class XMLRPCSystem:
"""Use XMLRPC to look up system attributes. This is the recommended
method.
The cache is controlled by the "cache" option and the "cache-time"
option
"""
cache = {}
def __init__(self, ip_address=None, mac_address=None):
name = None
resolve = True
# Try the cache.
if XMLRPCSystem.cache.has_key(ip_address):
cache_ent = XMLRPCSystem.cache[ip_address]
now = time.time()
cache_time = float(OPTIONS["cache-time"])
neg_cache_time = float(OPTIONS["neg-cache-time"])
if cache_ent["time"] + cache_time > now:
name = cache_ent["name"]
if name is not None:
logging.debug("Using cache name for system %s,%s"
% (cache_ent["name"],ip_address))
resolve = False
elif (name is None and mac_address is None and
cache_ent["time"] + neg_cache_time > now):
age = (cache_ent["time"] + neg_cache_time) - now
logging.debug("Using neg-cache for system %s:%f"
%(ip_address,age))
resolve = False
else:
age = (cache_ent["time"] + neg_cache_time) - now
logging.debug("ignoring cache for %s:%d"%(ip_address,age))
# Don't bother trying to find it.. until the neg-cache-time
# expires anyway
else:
del XMLRPCSystem.cache[ip_address]
# Not in the cache, try to find it.
if resolve:
query = {}
if mac_address is not None:
query["mac_address"] = mac_address.replace("-",":").upper()
elif ip_address is not None:
query["ip_address"] = ip_address
try:
logging.debug("Searching for system %s" % repr(query))
systems = COBBLER_HANDLE.find_system(query)
if len(systems) > 1:
raise RuntimeError("Args mapped to multiple systems")
elif len(systems) == 0:
raise RuntimeError("%s,%s not found in cobbler"
% (ip_address,mac_address))
name = systems[0]
except RuntimeError, e:
logging.info(str(e))
name = None
except:
(etype,eval,) = sys.exc_info()[:2]
logging.warn("Exception retrieving rendered system: %s (%s):%s"
% (name,eval,traceback.format_exc()))
name = None
if name is not None:
logging.debug("Materializing system %s" % name)
try:
self.system = COBBLER_HANDLE.get_system_for_koan(name)
self.attrs = self.system
self.name = self.attrs["name"]
except:
(etype,eval,) = sys.exc_info()[:2]
logging.warn ("Exception Materializing system %s (%s):%s"
% (name,eval,traceback.format_exc()))
if XMLRPCSystem.cache.has_key(ip_address):
del XMLRPCSystem.cache[ip_address]
self.system = None
self.attrs = dict()
self.name = str(ip_address)
else:
self.system = None
self.attrs = dict()
self.name = str(ip_address)
# fill the cache, negative entries too
if OPTIONS["cache"] and resolve:
logging.debug("Putting %s,%s into cache"%(name,ip_address))
XMLRPCSystem.cache[ip_address] = {
"name" : name,
"time" : time.time(),
}
class Request:
"""Handles the "business logic" of the TFTP server. One instance
is spawned per client request (RRQ packet received on well-known port)
and it is responsible for keeping track of where the file transfer
is..."""
def __init__(self,rrq_packet,local_sock,templar):
# Trim leading /s, since that's kinda implicit
self.filename = rrq_packet.filename.lstrip('/') # assumed
self.type = "chroot"
self.remote_addr = rrq_packet.remote_addr
self.req_options = rrq_packet.req_options
self.options = dict()
self.offset = 0
self.local_sock = local_sock
self.state = TFTP_OPCODE_RRQ
self.expand = False
self.templar = templar
# Sanitize input more
# Strip out \s
self.filename = self.filename.replace('\\','')
# Look for elements starting with ".", and blow up.
try:
if len(self.filename) == 0:
raise RuntimeError("Empty Path: ")
for elm in self.filename.split("/"):
if elm[0] == ".":
raise RuntimeError("Path includes '.': ")
except RuntimeError, e:
logging.warn(str(e) + rrq_packet.filename)
self.error_code = 2
self.error_str = "Invalid file name"
self.state = TFTP_OPCODE_ERROR
self.filename = None
OPTIONS["active"] += 1
self.system = XMLRPCSystem(self.remote_addr[0])
def _remap_strip_ip(self,filename):
# remove per-host IP or Mac prefixes, so that earlier pxelinux requests
# can be templated. We are already doing per-host stuff, so we don't
# need the IP addresses/mac addresses tacked on
# /<filename>/UUID (503a463c-537a-858b-af2a-519686f53c58)
# /<filename>/MAC (01-00-50-56-8b-33-88)
# /<filename>/IP (C000025B)
trimmed = filename
if self.system.system is None:
# If the file name has a mac address, strip that, use it to
# look up the system, and recurse.
m = re.compile("01((-[0-9a-f]{2}){6})$").search(filename)
if m:
# Found a mac address. try and look up a system
self.system = XMLRPCSystem(self.system.name,m.group(1)[1:])
if self.system.system is not None:
logging.info("Looked up host late: '%s'" % self.system.name)
return self._remap_strip_ip(filename)
# We can still trim off an ip address... system.name is the
# incoming ip
suffix = "/%08X" %unpack('!L',socket.inet_aton(self.system.name))[0]
if suffix and trimmed[len(trimmed)-len(suffix):] == suffix:
trimmed = trimmed.replace(suffix,"")
logging.debug('_remap_strip_ip: converted %s to %s'
% (filename, trimmed))
return trimmed
else:
# looking over all keys, because I have to search for keys I want
for (k,v) in self.system.system.iteritems():
suffix = False
# if I find a mac_address key or ip_address key, then see if
# that matches the file I'm looking at
if k.find("mac_address") >= 0 and v != '':
# the "01" is the ARP type of the interface. 01 is
# ethernet. This won't work for token ring, for example
suffix = "/01-" + v.replace(":","-").lower()
elif k.find("ip_address") >= 0 and v != '':
# IPv4 hardcoded here.
suffix = "/%08X" % unpack('!L',socket.inet_aton(v))[0]
if suffix and trimmed[len(trimmed)-len(suffix):] == suffix:
trimmed = trimmed.replace(suffix,"")
logging.debug('_remap_strip_ip: converted %s to %s'
% (filename, trimmed))
return trimmed
return filename
def _remap_via_profiles(self,filename):
pattern = re.compile("images/([^/]*)/(.*)")
m = pattern.match(filename)
if m:
logging.debug("client requesting distro?")
p = COBBLER_HANDLE.get_distro_for_koan(m.group(1))
if p:
logging.debug("%s matched distro %s" % (filename,p["name"]))
if m.group(2) == os.path.basename(p["kernel"]):
return p["kernel"],"template"
elif m.group(2) == os.path.basename(p["initrd"]):
return p["initrd"],"template"
logging.debug("but unknown file requested.")
else:
logging.debug("Couldn't load profile %s" % m.group(1))
return filename,"chroot"
def _remap_name_via_fetchable(self,filename):
fetchable_files = self.system.attrs["fetchable_files"].strip()
if not fetchable_files:
return filename,None
# We support two types of matches in fetchable_files
# * Direct match ("/foo=/bar")
# * Globs on directories ("/foo/*=/bar")
# A glob is realliy just a directory remap
glob_pattern = re.compile("(/)?[*]$")
# Look for the file in the fetchable_files hash
# XXX: Template name
for (k,v) in map(lambda x: x.split("="),fetchable_files.split(" ")):
k = k.lstrip('/') # Allow some slop w/ starting /s
# Full Path: "/foo=/bar"
result = None
if k == filename:
logging.debug('_remap_name: %s => %s' % (k,v))
result = v
# Glob Path: "/foo/*=/bar/"
else:
match = glob_pattern.search(k)
if match and fnmatch("/"+filename,"/"+k):
logging.debug('_remap_name (glob): %s => %s' % (k,v))
# Erase the trailing '/?[*]' in key
# Replace the matching leading portion in filename
# with the value
# Expand the result
if match.group(1):
lead_dir = glob_pattern.sub(match.group(1),k)
else:
lead_dir = glob_pattern.sub("",k)
result = filename.replace(lead_dir,v,1)
# Render the target, to expand things like "$kernel"
if result is not None:
try:
return self.templar.render(
result, self.system.attrs, None).strip(),"template"
except Cheetah.Parser.ParseError, e:
logging.warn('Unable to expand name: %s(%s): %s'
% (filename,result,e))
return filename,None
def _remap_name_via_boot_files(self,filename):
boot_files = self.system.attrs["boot_files"].strip()
if not boot_files:
logging.debug('_remap_name: no boot_files for %s/%s'
% (self.system,filename))
return filename,None
filename = filename.lstrip('/') # assumed
# Override "img_path", as that's the only variable used by
# the VMWare boot_files support, and they use a slightly different
# definition: one that's relative to tftpboot
attrs = self.system.attrs.copy()
attrs["img_path"] = os.path.join("images",attrs["distro_name"])
# Look for the file in the boot_files hash
for (k,v) in map(lambda x: x.split("="),boot_files.split(" ")):
k = k.lstrip('/') # Allow some slop w/ starting /s
# Render the key, to expand things like "$img_path"
try:
expanded_k = self.templar.render(k, attrs, None)
except Cheetah.Parser.ParseError, e:
logging.warn('Unable to expand name: %s(%s): %s'
% (filename,k,e))
continue
if expanded_k == filename:
# Render the target, to expand things like "$kernel"
logging.debug('_remap_name: %s => %s' % (expanded_k,v))
try:
return self.templar.render(v, attrs,None).strip(),"template"
except Cheetah.Parser.ParseError, e:
logging.warn('Unable to expand name: %s(%s): %s'
% (filename,v,e))
return filename,None
def _remap_name(self,filename):
filename = filename.lstrip('/') # assumed
# If possible, ignore pxelinux.0 added things we already know
trimmed = self._remap_strip_ip(filename)
if self.system.system is None:
# Look for image match. All we can do
return self._remap_via_profiles(trimmed)
# Specific hacks to handle the PXE/initrd case without any configuration
if self.system.attrs.has_key(trimmed):
if trimmed in ["pxelinux.cfg"]:
return trimmed,"hash_value"
elif trimmed in ["initrd"]:
return self.system.attrs[trimmed],"template"
# for the two tests below, I want to ignore "pytftp.*" in the string,
# which allows for some minimal control over extensions, which matters
# to pxelinux.0
noext = re.sub("pytftpd.*","",filename)
if self.system.attrs.has_key(noext) and noext in ["kernel"]:
return self.system.attrs[noext],"template"
(new_name,find_type) = self._remap_name_via_fetchable(trimmed)
if find_type is not None:
return new_name,find_type
(new_name,find_type) = self._remap_name_via_boot_files(trimmed)
if find_type is not None:
return new_name,find_type
# last try: try profiles
return self._remap_via_profiles(trimmed)
def _render_template(self):
try:
return RenderedFile(self.templar.render(open(self.filename,"r"),
self.system.attrs,None))
except Cheetah.Parser.ParseError, e:
logging.warn('Unable to expand template: %s: %s'
% (self.filename,e))
return None
except IOError, e:
logging.warn('Unable to expand template: %s: %s'
% (self.filename,e))
return None
def _setup_xfer(self):
"""Open the file to be loaded, or materalize the template.
This method can set the state to be an ERROR state, so
avoid setting state after calling this method.
"""
logging.info('host %s requesting %s' %
(self.system.name, self.filename))
self.filename,self.type = self._remap_name(self.filename)
logging.debug('host %s getting %s: %s' %
(self.system.name,self.filename,self.type))
if self.type == "template":
# TODO: Add file magic here
output = Popen([OPTIONS["file_cmd"],self.filename],
stdout=PIPE,stderr=STDOUT,
close_fds=True).communicate()[0]
if output.find(" text") >= 0:
self.file = self._render_template()
if self.file:
self.block_count = 0
self.file_size = len(self.file.data)
return
else:
logging.debug('Template failed to render.')
else:
logging.debug('Not rendering binary file %s (%s).'
% (self.filename,output))
elif self.type == "hash_value":
self.file = RenderedFile(self.system.attrs[self.filename])
self.block_count = 0
self.file_size = len(self.file.data)
return
else:
logging.debug('Relative path')
# Oh well. Look for the actual given file.
# XXX: add per-host IP or Mac prefixes?
# add: for pxeboot, or other non pxelinux
try:
logging.debug('starting xfer of %s to %s' %
(self.filename,self.remote_addr));
# Templates are specified by an absolute path
if self.type == "template":
self.file = open(self.filename,'rb',0)
else:
# TODO! restrict. Chroot?
# We are sanitizing in the input, but a second line of defense
# wouldn't be a bad idea
self.file = open(OPTIONS["prefix"] + "/" + self.filename,'rb',0)
self.block_count = 0
self.file_size = os.fstat(self.file.fileno()).st_size
except IOError:
logging.debug('%s requested %s: file not found.' %
(self.remote_addr, self.filename))
self.state = TFTP_OPCODE_ERROR
self.error_code = 1
self.error_str = "No such file"
return
def finish(self):
io_loop = ioloop.IOLoop.instance()
logging.debug("finishing req from %s for %s" %
(self.filename,self.remote_addr))
self.state = 0
try:
io_loop.remove_handler(self.local_sock.fileno())
logging.debug("closing fd %d" % self.local_sock.fileno())
self.local_sock.close()
except:
logging.debug("closed FD twice. Ignoring")
if self.timeout:
io_loop.remove_timeout(self.timeout)
self.timeout = None
OPTIONS["active"] -= 1
if (OPTIONS["idle"] > 0
and OPTIONS["active"] == 0 and OPTIONS["idle_timer"] is None):
io_loop.stop()
def handle_timeout(self):
# We timed out. We're done... (I hope)
logging.info('Timeout. Transfer of %s done' % self.filename)
self.timeout = None
self.finish()
def handle_input(self,packet):
"""The client sent us a new packet. Respond to it.
RRQ is handled in the constructor sequence, basically.
This should handle everything else"""
# We got input, so didn't time out. Refresh the timeout
io_loop = ioloop.IOLoop.instance()
io_loop.remove_timeout(self.timeout)
self.timeout = io_loop.add_timeout(time.time()+self.options["timeout"],
lambda : self.handle_timeout())
if packet.opcode == TFTP_OPCODE_ACK:
if self.state == TFTP_OPCODE_DATA:
# Incremement offset. They got the last bit
# the FFFF are to permit wrap. It's OK for the block
# number to wrap, since it's one client (and not unicast),
# so the client can figure that out.
if ( (packet.block_number & 0xFFFF) ==
((self.block_count + 1) & 0xFFFF)):
# Only update if they actually ack the packet we
# sent, but we'll still resend the last packet either way
self.block_count += 1
self.state = TFTP_OPCODE_ACK
elif self.state == TFTP_OPCODE_OACK:
# Ok, start feeding data
self.state = TFTP_OPCODE_ACK
elif packet.opcode == TFTP_OPCODE_ERROR:
logging.warn("Error from clients %s: %d:%s" %
(self.remote_addr, packet.error_code,
packet.error_str))
self.state = 0
else:
logging.warn("Unknown opcode from clients %s: %ds" %
(self.remote_addr, packet.opcode))
self.state = 0
def reply(self):
"""Given the current state, returns the next packet we should send
to the client"""
# Python doesn't have a switch statement (I presume on the theory
# that needing one means you didn't set your classes up right)
# so ... have a set of if/elif statements.
# Fast path: it's an ACK. Feed more data
if self.state == TFTP_OPCODE_ACK:
offset = self.block_count * self.options["blksize"]
if self.file_size < offset:
# We're done.
logging.info('Transfer of %s to %s done'
% (self.filename,self.remote_addr))
return None
self.file.seek(self.block_count * self.options["blksize"])
data = self.file.read(self.options["blksize"])
self.state = TFTP_OPCODE_DATA
# Block Count starts at 1, so offset
logging.log(9,"DATA to %s/%d, block_count %d/%d, size %d(%d/%d)" % (
self.remote_addr[0],self.remote_addr[1],
self.block_count + 1, (self.block_count+1)&0xFFFF,
len(data),offset+len(data),self.file_size))
return DATAPacket(data, self.block_count + 1)
if self.state == 0:
return None
if self.state == TFTP_OPCODE_ERROR:
# Don't bother waiting.. this was the first request
# a "resend" would go to the well known port
return ERRORPacket(self.error_code,self.error_str)
if self.state == TFTP_OPCODE_RRQ and self.req_options:
# They asked for various rfc2347 options. Figure out
# what we'll allow, and send an OACK.
self.state = TFTP_OPCODE_OACK
# Most clients will ask for tsize, which is the size of the
# file we'll be giving them. Let's look that up.
self._setup_xfer()
# Check for an error loading the file
if self.state == TFTP_OPCODE_ERROR:
# Don't bother waiting.. this was the first request
# a "resend" would go to the well known port
return ERRORPacket(self.error_code,self.error_str)
# make sure we have defaults
self.options = dict(
blksize = OPTIONS["blksize"],
timeout = OPTIONS["timeout"]);
accepted_opts = []
# Sorry for the excessive complexity here.
# I'm trying to maintain client's case and order, to protect
# against braindamaged clients. Given clients are frequently
# written in assembly, they can be excused some braindamage
logging.debug("Requested options: %s"%(repr(self.req_options)))
for i in range(0,len(self.req_options),2):
key = self.req_options[i]
value = self.req_options[i+1]
logging.debug("looking at key %s" % (key))
if key.lower() == "tsize":
accepted_opts.append(key)
accepted_opts.append(self.file_size)
elif ("min_"+key).lower() in OPTIONS:
value = int(value) # string
# if it's an option we know about/can bound
upper_bound = OPTIONS[("max_"+key).lower()]
lower_bound = OPTIONS[("min_"+key).lower()]
logging.debug("%s: req: %d (%d - %d)"
% (key,value,lower_bound,upper_bound))
if value < lower_bound:
value = lower_bound
if value > upper_bound:
value = upper_bound
self.options[key.lower()] = value
accepted_opts.append(key)
accepted_opts.append(str(value))
else:
# ignore it, do not include in the OACK
logging.info("Unknown option requested %s" % (key))
logging.debug("Using Options: %s"%(repr(self.options)))
return OACKPacket(accepted_opts)
if self.state == TFTP_OPCODE_RRQ:
# No options. Fill in the defaults
# and then recurse, pretending we just got the ACK to our OACK
self.options = dict(
blksize = OPTIONS["blksize"],
timeout = OPTIONS["timeout"]);
logging.debug("Using Options: %s"%(repr(self.options)))
self.state = TFTP_OPCODE_ACK
self._setup_xfer()
if self.state == TFTP_OPCODE_ERROR:
return ERRORPacket(self.error_code,self.error_str)
return self.reply()
raise NotImplementedError("Unknown state %d" % (self.state))
REQ_NAME = 0
REQ_CLASS = 1
REQUESTS = [
[ "INVALID", None ], # 0
[ "RRQ", RRQPacket ], # 1
[ "WRQ", None ], # 2
[ "DATA", None ], # 3
[ "ACK", ACKPacket ], # 4
[ "ERROR", None ], # 5
[ "OACK", OACKPacket ] # 6
]
def read_packet(data,local_sock,remote_addr):
"""Object factory. Reads the first tiny bit of the packet to get the
opcode, and returns a Packet object of the relevant type
Returns None on failure
"""
packet = None
opcode, = unpack("!H",data[0:2])
if opcode < 1 or opcode > 6:
logging.warn("Unknown request id %d from %s" % (opcode,remote_addr))
local_sock.sendto(ERRORPacket(0,"Unknown request").marshall(),
remote_addr)
return None
if REQUESTS[opcode][REQ_CLASS] == None:
if opcode != TFTP_OPCODE_ERROR:
logging.warn("Unsupported request %d(%s) from %s"
% (opcode,REQUESTS[opcode][REQ_NAME],remote_addr))
local_sock.sendto(
ERRORPacket(2,"Unsupported request").marshall(),remote_addr)
return None
try:
return (REQUESTS[opcode][REQ_CLASS])(data,local_sock,remote_addr)
except:
return None
def partial(func, *args, **keywords):
"""Method factory. Returns a semi-anonymous method that provides
certain arguments to another method.
Usually could be replaced by a lambda expression
Example:
def add(i,j):
return i+j
fn = partial(add,1) # always pass 1 as the first arg to add
fn(2) # returns 1+2
"""
def newfunc(*fargs, **fkeywords):
newkeywords = keywords.copy()
newkeywords.update(fkeywords)
return func(*(args + fargs), **newkeywords)
newfunc.func = func
newfunc.args = args
newfunc.keywords = keywords
return newfunc
def handle_request(request,fd,events):
"""Used as the IO handler for subsequent requests. Followup
packets for a given request are sent to a different port, because
UDP doesn't have it's own connection concept. Also packets
can be larger after option negotiation, so the amount to read
can vary.
This method handles packets sent to the transient ports,
and calls the Request.handle_input method of the request associated
with the port.
"""
try:
while request.state != 0: # 0 is the "done" state
try:
data,address = request.local_sock.recvfrom(
request.options["blksize"]);
except socket.error, e:
if e[0] in (errno.EWOULDBLOCK, errno.EAGAIN):
return
else:
raise
if address == request.remote_addr:
packet = read_packet(data,request.local_sock,address)
if (packet is None):
request.finish()
continue
request.handle_input(packet)
reply = request.reply()
if reply:
request.local_sock.sendto(reply.marshall(),address)
if not reply or reply is ERRORPacket:
request.finish()
else:
raise NotImplementedError("Input from unexpected source")
finally:
# Reset the timer
if OPTIONS["idle"] > 0:
io_loop = ioloop.IOLoop.instance()
try:
io_loop.remove_timeout(OPTIONS["idle_timer"])
except:
pass
OPTIONS["idle_timer"] = io_loop.add_timeout(
time.time()+OPTIONS["idle"],
lambda : idle_out())
def idle_out():
logging.info("Idling out")
io_loop = ioloop.IOLoop.instance()
io_loop.remove_handler(OPTIONS["sock"].fileno())
OPTIONS["sock"].close()
if OPTIONS["active"] == 0:
OPTIONS["idle_timer"] = None
io_loop.stop()
# called from ioloop.py:245
def new_req(sock, templar, fd, events):
"""The IO handler for the well-known port. Handles the RRQ
packet of a known size (512), and sets up the transient port
for future messages for the same request.
"""
io_loop = ioloop.IOLoop.instance()
if OPTIONS["idle"] > 0:
try:
io_loop.remove_timeout(OPTIONS["idle_timer"])
except:
pass
while True:
try:
data,address = sock.recvfrom(OPTIONS["blksize"]);
except socket.error, e:
if e[0] not in (errno.EWOULDBLOCK, errno.EAGAIN):
raise
break
packet = read_packet(data,sock,address)
# this is the new_request handler. (packet had better be an RRQ
# request)
if packet is None or packet.opcode != TFTP_OPCODE_RRQ:
local_sock.sendto(
ERRORPacket(2,"Unsupported initial request").marshall(),address)
break
# Create the new transient port for this request
new_address = socket.socket(socket.AF_INET,socket.SOCK_DGRAM, 0)
new_address.bind(("",0)) # random port: XXX control?
logging.debug("Bound to transient socket %d" %
new_address.getsockname()[1])
new_address.setblocking(0)
packet.local_sock = new_address
# Create the request object to handle this request, and bind it
# to IO from the transient port
request = Request(packet,new_address,templar)
io_loop.add_handler(
new_address.fileno(),
partial(handle_request,request),
io_loop.READ)
request.timeout = io_loop.add_timeout(time.time() + OPTIONS["timeout"],
lambda : request.handle_timeout())
# Ask the request what to do now..
reply = request.reply()
if reply:
new_address.sendto(reply.marshall(),address)
if not reply or reply.is_error():
request.finish()
# After the while loop. Re-add the idle timer
if OPTIONS["idle"] > 0:
OPTIONS["idle_timer"] = io_loop.add_timeout(time.time()+OPTIONS["idle"],
lambda : idle_out())
def main():
# If we're called from xinetd, set idle to non-zero
mode = os.fstat(sys.stdin.fileno()).st_mode
if stat.S_ISSOCK(mode):
OPTIONS["idle"] = 30
OPTIONS["logger"] = "syslog"
# setup option parsing
opt_help = dict(
port = dict(type="int",help="The port to bind to for new requests"),
idle = dict(type="int",help="How long to wait for input"),
timeout= dict(type="int",help="How long to wait for a given request"),
max_blksize=dict(type="int", help="The maximum block size to permit" ),
prefix = dict(type="string",
help="Where files are stored by default ["
+OPTIONS["prefix"]+"]"),
logger = dict(type="string",help="How to log"),
file_cmd= dict(type="string",help="The location of the 'file' command"),
user = dict(type="string",help="The user to run as [nobody]"),
)
parser = optparse.OptionParser(
formatter=optparse.IndentedHelpFormatter(),
usage=globals()['__doc__'],
version=VERSION)
parser.add_option('-v','--verbose',action='store_true',default=False,
help="Increase output verbosity")
parser.add_option('-d','--debug',action='store_true',default=False,
help="Debug (vastly increases output verbosity)")
parser.add_option('-c','--cache',action='store_true',default=True,
help="Use a cache to help find hosts w/o IP address")
parser.add_option('--cache-time',action='store',type="int",default=5*60,
help="How long an ip->name mapping is valid")
parser.add_option('--neg-cache-time',action='store',type="int",default=10,
help="How long an ip->name mapping is valid")
opts = opt_help.keys()
opts.sort()
for k in opts:
v = opt_help[k]
parser.add_option("--"+k,default=OPTIONS[k],
type=v["type"],help=v["help"])
parser.add_option('-B',dest="max_blksize",type="int",default=1428,
help="alias for --max-blksize, for in.tftpd compatibility")
# Actually read the args
(options,args) = parser.parse_args()
for attr in dir(options):
if attr in OPTIONS:
OPTIONS[attr] = getattr(options,attr)
if stat.S_ISSOCK(mode) or OPTIONS["logger"] == "syslog":
# log to syslog. Facility 11 isn't in the class, but it's FTP on linux
logger = logging.handlers.SysLogHandler("/dev/log", 11)
logger.setFormatter(
logging.Formatter('%(filename)s: %(levelname)s: %(message)s'))
elif OPTIONS["logger"] == "stream":
# log to stdout
logger = logging.StreamHandler()
logger.setFormatter(logging.Formatter(logging.BASIC_FORMAT))
else:
logger = logging.FileHandler("/var/log/tftpd")
logger.setFormatter(logging.Formatter(
"%(asctime)s %(name)s: %(levelname)s: %(message)s"))
logging.getLogger().addHandler(logger)
if OPTIONS["debug"]:
logging.getLogger().setLevel(logging.DEBUG)
elif OPTIONS["verbose"]:
logging.getLogger().setLevel(logging.INFO)
else:
logging.getLogger().setLevel(logging.WARN)
if stat.S_ISSOCK(mode):
OPTIONS["sock"] = socket.fromfd(sys.stdin.fileno(),
socket.AF_INET,
socket.SOCK_DGRAM,
0)
else:
OPTIONS["sock"] = socket.socket(socket.AF_INET,socket.SOCK_DGRAM, 0)
OPTIONS["sock"].setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
try:
OPTIONS["sock"].bind(("",OPTIONS["port"]))
except socket.error, e:
if e[0] in (errno.EPERM, errno.EACCES):
print "Unable to bind to port %d" % OPTIONS["port"]
return -1
else:
raise
OPTIONS["sock"].setblocking(0)
if os.getuid() == 0:
uid = pwd.getpwnam(OPTIONS["user"])[2]
os.setreuid(uid,uid)
# This takes a while, so do it after we open the port, so we
# don't drop the packet that spawned us
templar = cobbler.templar.Templar(None)
io_loop = ioloop.IOLoop.instance()
io_loop.add_handler(OPTIONS["sock"].fileno(),
partial(new_req,OPTIONS["sock"],templar),io_loop.READ)
# Shove the timeout into OPTIONS, because it's there
if OPTIONS["idle"] > 0:
OPTIONS["idle_timer"] = io_loop.add_timeout(time.time()+OPTIONS["idle"],
lambda : idle_out())
logging.info('Starting Eventloop')
try:
try:
io_loop.start()
except KeyboardInterrupt:
# Someone hit ^C
logging.info('Exiting')
finally:
OPTIONS["sock"].close()
return 0
if __name__ == "__main__":
sys.exit(main())
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