initial checkin

8 files changed, 780 insertions, 0 deletions

diff --git a/Demo/dns/README b/Demo/dns/README
new file mode 100644
index 0000000..09ebe8f
--- /dev/null
+++ b/Demo/dns/README
@@ -0,0 +1,12 @@
+This directory contains a module (dnslib) that implements a DNS
+(Domain Name Server) client, plus additional modules that define some
+symbolic constants used by DNS (dnstype, dnsclass, dnsopcode).
+
+Type "python dnslib.py -/" for a usage message.
+
+You can also import dnslib and write your own, more sophisticated
+client code; use the test program as an example (there is currently no
+documentation :-).
+
+--Guido van Rossum, CWI, Amsterdam <Guido.van.Rossum@cwi.nl>
+URL:  <http://www.cwi.nl/cwi/people/Guido.van.Rossum.html>
diff --git a/Demo/dns/dnsclass.py b/Demo/dns/dnsclass.py
new file mode 100755
index 0000000..f90b9e8
--- /dev/null
+++ b/Demo/dns/dnsclass.py
@@ -0,0 +1,23 @@
+# CLASS values (section 3.2.4)
+
+IN = 1		# the Internet
+CS = 2		# the CSNET class (Obsolete - used only for examples in
+		# some obsolete RFCs)
+CH = 3		# the CHAOS class
+HS = 4		# Hesiod [Dyer 87]
+
+# QCLASS values (section 3.2.5)
+
+ANY = 255	# any class
+
+
+# Construct reverse mapping dictionary
+
+_names = dir()
+classmap = {}
+for _name in _names:
+	if _name[0] != '_': classmap[eval(_name)] = _name
+
+def classstr(klass):
+	if classmap.has_key(klass): return classmap[klass]
+	else: return `klass`
diff --git a/Demo/dns/dnslib.py b/Demo/dns/dnslib.py
new file mode 100755
index 0000000..9f0a3f4
--- /dev/null
+++ b/Demo/dns/dnslib.py
@@ -0,0 +1,588 @@
+# Domain Name Server (DNS) interface
+#
+# See RFC 1035:
+# ------------------------------------------------------------------------
+# Network Working Group                                     P. Mockapetris
+# Request for Comments: 1035                                           ISI
+#                                                            November 1987
+# Obsoletes: RFCs 882, 883, 973
+# 
+#             DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION
+# ------------------------------------------------------------------------
+
+
+import string
+
+import dnstype
+import dnsclass
+import dnsopcode
+
+
+# Low-level 16 and 32 bit integer packing and unpacking
+
+def pack16bit(n):
+	return chr((n>>8)&0xFF) + chr(n&0xFF)
+
+def pack32bit(n):
+	return chr((n>>24)&0xFF) + chr((n>>16)&0xFF) \
+		  + chr((n>>8)&0xFF) + chr(n&0xFF)
+
+def unpack16bit(s):
+	return (ord(s[0])<<8) | ord(s[1])
+
+def unpack32bit(s):
+	return (ord(s[0])<<24) | (ord(s[1])<<16) \
+		  | (ord(s[2])<<8) | ord(s[3])
+
+def addr2bin(addr):
+	if type(addr) == type(0):
+		return addr
+	bytes = string.splitfields(addr, '.')
+	if len(bytes) != 4: raise ValueError, 'bad IP address'
+	n = 0
+	for byte in bytes: n = n<<8 | string.atoi(byte)
+	return n
+
+def bin2addr(n):
+	return '%d.%d.%d.%d' % ((n>>24)&0xFF, (n>>16)&0xFF,
+		  (n>>8)&0xFF, n&0xFF)
+
+
+# Packing class
+
+class Packer:
+	def __init__(self):
+		self.buf = ''
+		self.index = {}
+	def getbuf(self):
+		return self.buf
+	def addbyte(self, c):
+		if len(c) != 1: raise TypeError, 'one character expected'
+		self.buf = self.buf + c
+	def addbytes(self, bytes):
+		self.buf = self.buf + bytes
+	def add16bit(self, n):
+		self.buf = self.buf + pack16bit(n)
+	def add32bit(self, n):
+		self.buf = self.buf + pack32bit(n)
+	def addaddr(self, addr):
+		n = addr2bin(addr)
+		self.buf = self.buf + pack32bit(n)
+	def addstring(self, s):
+		self.addbyte(chr(len(s)))
+		self.addbytes(s)
+	def addname(self, name):
+		# Domain name packing (section 4.1.4)
+		# Add a domain name to the buffer, possibly using pointers.
+		# The case of the first occurrence of a name is preserved.
+		# Redundant dots are ignored.
+		list = []
+		for label in string.splitfields(name, '.'):
+			if label:
+				if len(label) > 63:
+					raise PackError, 'label too long'
+				list.append(label)
+		keys = []
+		for i in range(len(list)):
+			key = string.upper(string.joinfields(list[i:], '.'))
+			keys.append(key)
+			if self.index.has_key(key):
+				pointer = self.index[key]
+				break
+		else:
+			i = len(list)
+			pointer = None
+		# Do it into temporaries first so exceptions don't
+		# mess up self.index and self.buf
+		buf = ''
+		offset = len(self.buf)
+		index = []
+		for j in range(i):
+			label = list[j]
+			n = len(label)
+			if offset + len(buf) < 0x3FFF:
+				index.append(keys[j], offset + len(buf))
+			else:
+				print 'dnslib.Packer.addname:',
+				print 'warning: pointer too big'
+			buf = buf + (chr(n) + label)
+		if pointer:
+			buf = buf + pack16bit(pointer | 0xC000)
+		else:
+			buf = buf + '\0'
+		self.buf = self.buf + buf
+		for key, value in index:
+			self.index[key] = value
+	def dump(self):
+		keys = self.index.keys()
+		keys.sort()
+		print '-'*40
+		for key in keys:
+			print '%20s %3d' % (key, self.index[key])
+		print '-'*40
+		space = 1
+		for i in range(0, len(self.buf)+1, 2):
+			if self.buf[i:i+2] == '**':
+				if not space: print
+				space = 1
+				continue
+			space = 0
+			print '%4d' % i,
+			for c in self.buf[i:i+2]:
+				if ' ' < c < '\177':
+					print ' %c' % c,
+				else:
+					print '%2d' % ord(c),
+			print
+		print '-'*40
+
+
+# Unpacking class
+
+UnpackError = 'dnslib.UnpackError'	# Exception
+
+class Unpacker:
+	def __init__(self, buf):
+		self.buf = buf
+		self.offset = 0
+	def getbyte(self):
+		c = self.buf[self.offset]
+		self.offset = self.offset + 1
+		return c
+	def getbytes(self, n):
+		s = self.buf[self.offset : self.offset + n]
+		if len(s) != n: raise UnpackError, 'not enough data left'
+		self.offset = self.offset + n
+		return s
+	def get16bit(self):
+		return unpack16bit(self.getbytes(2))
+	def get32bit(self):
+		return unpack32bit(self.getbytes(4))
+	def getaddr(self):
+		return bin2addr(self.get32bit())
+	def getstring(self):
+		return self.getbytes(ord(self.getbyte()))
+	def getname(self):
+		# Domain name unpacking (section 4.1.4)
+		c = self.getbyte()
+		i = ord(c)
+		if i & 0xC0 == 0xC0:
+			d = self.getbyte()
+			j = ord(d)
+			pointer = ((i<<8) | j) & ~0xC000
+			save_offset = self.offset
+			try:
+				self.offset = pointer
+				domain = self.getname()
+			finally:
+				self.offset = save_offset
+			return domain
+		if i == 0:
+			return ''
+		domain = self.getbytes(i)
+		remains = self.getname()
+		if not remains:
+			return domain
+		else:
+			return domain + '.' + remains
+
+
+# Test program for packin/unpacking (section 4.1.4)
+
+def testpacker():
+	N = 25
+	R = range(N)
+	import timing
+	# See section 4.1.4 of RFC 1035
+	timing.start()
+	for i in R:
+		p = Packer()
+		p.addbytes('*' * 20)
+		p.addname('f.ISI.ARPA')
+		p.addbytes('*' * 8)
+		p.addname('Foo.F.isi.arpa')
+		p.addbytes('*' * 18)
+		p.addname('arpa')
+		p.addbytes('*' * 26)
+		p.addname('')
+	timing.finish()
+	print round(timing.milli() * 0.001 / N, 3), 'seconds per packing'
+	p.dump()
+	u = Unpacker(p.buf)
+	u.getbytes(20)
+	u.getname()
+	u.getbytes(8)
+	u.getname()
+	u.getbytes(18)
+	u.getname()
+	u.getbytes(26)
+	u.getname()
+	timing.start()
+	for i in R:
+		u = Unpacker(p.buf)
+		res = (u.getbytes(20),
+		       u.getname(),
+		       u.getbytes(8),
+		       u.getname(),
+		       u.getbytes(18),
+		       u.getname(),
+		       u.getbytes(26),
+		       u.getname())
+	timing.finish()
+	print round(timing.milli() * 0.001 / N, 3), 'seconds per unpacking'
+	for item in res: print item
+
+
+# Pack/unpack RR toplevel format (section 3.2.1)
+
+class RRpacker(Packer):
+	def __init__(self):
+		Packer.__init__(self)
+		self.rdstart = None
+	def addRRheader(self, name, type, klass, ttl, *rest):
+		self.addname(name)
+		self.add16bit(type)
+		self.add16bit(klass)
+		self.add32bit(ttl)
+		if rest:
+			if res[1:]: raise TypeError, 'too many args'
+			rdlength = rest[0]
+		else:
+			rdlength = 0
+		self.add16bit(rdlength)
+		self.rdstart = len(self.buf)
+	def patchrdlength(self):
+		rdlength = unpack16bit(self.buf[self.rdstart-2:self.rdstart])
+		if rdlength == len(self.buf) - self.rdstart:
+			return
+		rdata = self.buf[self.rdstart:]
+		save_buf = self.buf
+		ok = 0
+		try:
+			self.buf = self.buf[:self.rdstart-2]
+			self.add16bit(len(rdata))
+			self.buf = self.buf + rdata
+			ok = 1
+		finally:
+			if not ok: self.buf = save_buf
+	def endRR(self):
+		if self.rdstart is not None:
+			self.patchrdlength()
+		self.rdstart = None
+	def getbuf(self):
+		if self.rdstart is not None: self.patchrdlenth()
+		return Packer.getbuf(self)
+	# Standard RRs (section 3.3)
+	def addCNAME(self, name, klass, ttl, cname):
+		self.addRRheader(name, dnstype.CNAME, klass, ttl)
+		self.addname(cname)
+		self.endRR()
+	def addHINFO(self, name, klass, ttl, cpu, os):
+		self.addRRheader(name, dnstype.HINFO, klass, ttl)
+		self.addstring(cpu)
+		self.addstring(os)
+		self.endRR()
+	def addMX(self, name, klass, ttl, preference, exchange):
+		self.addRRheader(name, dnstype.MX, klass, ttl)
+		self.add16bit(preference)
+		self.addname(exchange)
+		self.endRR()
+	def addNS(self, name, klass, ttl, nsdname):
+		self.addRRheader(name, dnstype.NS, klass, ttl)
+		self.addname(nsdname)
+		self.endRR()
+	def addPTR(self, name, klass, ttl, ptrdname):
+		self.addRRheader(name, dnstype.PTR, klass, ttl)
+		self.addname(ptrdname)
+		self.endRR()
+	def addSOA(self, name, klass, ttl,
+		  mname, rname, serial, refresh, retry, expire, minimum):
+		self.addRRheader(name, dnstype.SOA, klass, ttl)
+		self.addname(mname)
+		self.addname(rname)
+		self.add32bit(serial)
+		self.add32bit(refresh)
+		self.add32bit(retry)
+		self.add32bit(expire)
+		self.add32bit(minimum)
+		self.endRR()
+	def addTXT(self, name, klass, ttl, list):
+		self.addRRheader(name, dnstype.TXT, klass, ttl)
+		for txtdata in list:
+			self.addstring(txtdata)
+		self.endRR()
+	# Internet specific RRs (section 3.4) -- class = IN
+	def addA(self, name, ttl, address):
+		self.addRRheader(name, dnstype.A, dnsclass.IN, ttl)
+		self.addaddr(address)
+		self.endRR()
+	def addWKS(self, name, ttl, address, protocol, bitmap):
+		self.addRRheader(name, dnstype.WKS, dnsclass.IN, ttl)
+		self.addaddr(address)
+		self.addbyte(chr(protocol))
+		self.addbytes(bitmap)
+		self.endRR()
+
+
+class RRunpacker(Unpacker):
+	def __init__(self, buf):
+		Unpacker.__init__(self, buf)
+		self.rdend = None
+	def getRRheader(self):
+		name = self.getname()
+		type = self.get16bit()
+		klass = self.get16bit()
+		ttl = self.get32bit()
+		rdlength = self.get16bit()
+		self.rdend = self.offset + rdlength
+		return (name, type, klass, ttl, rdlength)
+	def endRR(self):
+		if self.offset != self.rdend:
+			raise UnpackError, 'end of RR not reached'
+	def getCNAMEdata(self):
+		return self.getname()
+	def getHINFOdata(self):
+		return self.getstring(), self.getstring()
+	def getMXdata(self):
+		return self.get16bit(), self.getname()
+	def getNSdata(self):
+		return self.getname()
+	def getPTRdata(self):
+		return self.getname()
+	def getSOAdata(self):
+		return self.getname(), \
+		       self.getname(), \
+		       self.get32bit(), \
+		       self.get32bit(), \
+		       self.get32bit(), \
+		       self.get32bit(), \
+		       self.get32bit()
+	def getTXTdata(self):
+		list = []
+		while self.offset != self.rdend:
+			list.append(self.getstring())
+		return list
+	def getAdata(self):
+		return self.getaddr()
+	def getWKSdata(self):
+		address = self.getaddr()
+		protocol = ord(self.getbyte())
+		bitmap = self.getbytes(self.rdend - self.offset)
+		return address, protocol, bitmap
+
+
+# Pack/unpack Message Header (section 4.1)
+
+class Hpacker(Packer):
+	def addHeader(self, id, qr, opcode, aa, tc, rd, ra, z, rcode,
+		  qdcount, ancount, nscount, arcount):
+		self.add16bit(id)
+		self.add16bit((qr&1)<<15 | (opcode*0xF)<<11 | (aa&1)<<10
+			  | (tc&1)<<9 | (rd&1)<<8 | (ra&1)<<7
+			  | (z&7)<<4 | (rcode&0xF))
+		self.add16bit(qdcount)
+		self.add16bit(ancount)
+		self.add16bit(nscount)
+		self.add16bit(arcount)
+
+class Hunpacker(Unpacker):
+	def getHeader(self):
+		id = self.get16bit()
+		flags = self.get16bit()
+		qr, opcode, aa, tc, rd, ra, z, rcode = (
+			  (flags>>15)&1,
+			  (flags>>11)&0xF,
+			  (flags>>10)&1,
+			  (flags>>9)&1,
+			  (flags>>8)&1,
+			  (flags>>7)&1,
+			  (flags>>4)&7,
+			  (flags>>0)&0xF)
+		qdcount = self.get16bit()
+		ancount = self.get16bit()
+		nscount = self.get16bit()
+		arcount = self.get16bit()
+		return (id, qr, opcode, aa, tc, rd, ra, z, rcode,
+			  qdcount, ancount, nscount, arcount)
+
+
+# Pack/unpack Question (section 4.1.2)
+
+class Qpacker(Packer):
+	def addQuestion(self, qname, qtype, qclass):
+		self.addname(qname)
+		self.add16bit(qtype)
+		self.add16bit(qclass)
+
+class Qunpacker(Unpacker):
+	def getQuestion(self):
+		return self.getname(), self.get16bit(), self.get16bit()
+
+
+# Pack/unpack Message(section 4)
+# NB the order of the base classes is important for __init__()!
+
+class Mpacker(RRpacker, Qpacker, Hpacker):
+	pass
+
+class Munpacker(RRunpacker, Qunpacker, Hunpacker):
+	pass
+
+
+# Routines to print an unpacker to stdout, for debugging.
+# These affect the unpacker's current position!
+
+def dumpM(u):
+	print 'HEADER:',
+	(id, qr, opcode, aa, tc, rd, ra, z, rcode,
+		  qdcount, ancount, nscount, arcount) = u.getHeader()
+	print 'id=%d,' % id,
+	print 'qr=%d, opcode=%d, aa=%d, tc=%d, rd=%d, ra=%d, z=%d, rcode=%d,' \
+		  % (qr, opcode, aa, tc, rd, ra, z, rcode)
+	if tc: print '*** response truncated! ***'
+	if rcode: print '*** nonzero error code! (%d) ***' % rcode
+	print '  qdcount=%d, ancount=%d, nscount=%d, arcount=%d' \
+		  % (qdcount, ancount, nscount, arcount)
+	for i in range(qdcount):
+		print 'QUESTION %d:' % i,
+		dumpQ(u)
+	for i in range(ancount):
+		print 'ANSWER %d:' % i,
+		dumpRR(u)
+	for i in range(nscount):
+		print 'AUTHORITY RECORD %d:' % i,
+		dumpRR(u)
+	for i in range(arcount):
+		print 'ADDITIONAL RECORD %d:' % i,
+		dumpRR(u)
+
+def dumpQ(u):
+	qname, qtype, qclass = u.getQuestion()
+	print 'qname=%s, qtype=%d(%s), qclass=%d(%s)' \
+		  % (qname,
+		     qtype, dnstype.typestr(qtype),
+		     qclass, dnsclass.classstr(qclass))
+
+def dumpRR(u):
+	name, type, klass, ttl, rdlength = u.getRRheader()
+	typename = dnstype.typestr(type)
+	print 'name=%s, type=%d(%s), class=%d(%s), ttl=%d' \
+		  % (name,
+		     type, typename,
+		     klass, dnsclass.classstr(klass),
+		     ttl)
+	mname = 'get%sdata' % typename
+	if hasattr(u, mname):
+		print '  formatted rdata:', getattr(u, mname)()
+	else:
+		print '  binary rdata:', u.getbytes(rdlength)
+
+
+# Test program
+
+def test():
+	import sys
+	import getopt
+	import socket
+	protocol = 'udp'
+	server = 'meermin.cwi.nl' # XXX adapt this to your local 
+	port = 53
+	opcode = dnsopcode.QUERY
+	rd = 0
+	qtype = dnstype.MX
+	qname = 'cwi.nl'
+	try:
+		opts, args = getopt.getopt(sys.argv[1:], 'Trs:tu')
+		if len(args) > 2: raise getopt.error, 'too many arguments'
+	except getopt.error, msg:
+		print msg
+		print 'Usage: python dnslib.py',
+		print '[-T] [-r] [-s server] [-t] [-u]',
+		print '[qtype [qname]]'
+		print '-T:        run testpacker() and exit'
+		print '-r:        recursion desired (default not)'
+		print '-s server: use server (default %s)' % server
+		print '-t:        use TCP protocol'
+		print '-u:        use UDP protocol (default)'
+		print 'qtype:     query type (default %s)' % \
+			  dnstype.typestr(qtype)
+		print 'qname:     query name (default %s)' % qname
+		print 'Recognized qtype values:'
+		qtypes = dnstype.typemap.keys()
+		qtypes.sort()
+		n = 0
+		for qtype in qtypes:
+			n = n+1
+			if n >= 8: n = 1; print
+			print '%s = %d' % (dnstype.typemap[qtype], qtype),
+		print
+		sys.exit(2)
+	for o, a in opts:
+		if o == '-T': testpacker(); return
+		if o == '-t': protocol = 'tcp'
+		if o == '-u': protocol = 'udp'
+		if o == '-s': server = a
+		if o == '-r': rd = 1
+	if args[0:]:
+		try:
+			qtype = eval(string.upper(args[0]), dnstype.__dict__)
+		except (NameError, SyntaxError):
+			print 'bad query type:', `args[0]`
+			sys.exit(2)
+	if args[1:]:
+		qname = args[1]
+	if qtype == dnstype.AXFR:
+		print 'Query type AXFR, protocol forced to TCP'
+		protocol = 'tcp'
+	print 'QTYPE %d(%s)' % (qtype, dnstype.typestr(qtype))
+	m = Mpacker()
+	m.addHeader(0,
+		  0, opcode, 0, 0, rd, 0, 0, 0,
+		  1, 0, 0, 0)
+	m.addQuestion(qname, qtype, dnsclass.IN)
+	request = m.getbuf()
+	if protocol == 'udp':
+		s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+		s.connect((server, port))
+		s.send(request)
+		reply = s.recv(1024)
+	else:
+		s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+		s.connect((server, port))
+		s.send(pack16bit(len(request)) + request)
+		s.shutdown(1)
+		f = s.makefile('r')
+		header = f.read(2)
+		if len(header) < 2:
+			print '*** EOF ***'
+			return
+		count = unpack16bit(header)
+		reply = f.read(count)
+		if len(reply) != count:
+			print '*** Incomplete reply ***'
+			return
+	u = Munpacker(reply)
+	dumpM(u)
+	if protocol == 'tcp' and qtype == dnstype.AXFR:
+		while 1:
+			header = f.read(2)
+			if len(header) < 2:
+				print '========== EOF =========='
+				break
+			count = unpack16bit(header)
+			if not count:
+				print '========== ZERO COUNT =========='
+				break
+			print '========== NEXT =========='
+			reply = f.read(count)
+			if len(reply) != count:
+				print '*** Incomplete reply ***'
+				break
+			u = Munpacker(reply)
+			dumpM(u)
+
+
+# Run test program when called as a script
+
+if __name__ == '__main__':
+	test()
diff --git a/Demo/dns/dnsopcode.py b/Demo/dns/dnsopcode.py
new file mode 100755
index 0000000..f2e7cd5
--- /dev/null
+++ b/Demo/dns/dnsopcode.py
@@ -0,0 +1,16 @@
+# Opcode values in message header (section 4.1.1)
+
+QUERY = 0
+IQUERY = 1
+STATUS = 2
+
+# Construct reverse mapping dictionary
+
+_names = dir()
+opcodemap = {}
+for _name in _names:
+	if _name[0] != '_': opcodemap[eval(_name)] = _name
+
+def opcodestr(opcode):
+	if opcodemap.has_key(opcode): return opcodemap[opcode]
+	else: return `opcode`
diff --git a/Demo/dns/dnstype.py b/Demo/dns/dnstype.py
new file mode 100755
index 0000000..80c2b76
--- /dev/null
+++ b/Demo/dns/dnstype.py
@@ -0,0 +1,41 @@
+# TYPE values (section 3.2.2)
+
+A = 1		# a host address
+NS = 2		# an authoritative name server
+MD = 3		# a mail destination (Obsolete - use MX)
+MF = 4		# a mail forwarder (Obsolete - use MX)
+CNAME = 5	# the canonical name for an alias
+SOA = 6		# marks the start of a zone of authority
+MB = 7		# a mailbox domain name (EXPERIMENTAL)
+MG = 8		# a mail group member (EXPERIMENTAL)
+MR = 9		# a mail rename domain name (EXPERIMENTAL)
+NULL = 10	# a null RR (EXPERIMENTAL)
+WKS = 11	# a well known service description
+PTR = 12	# a domain name pointer
+HINFO = 13	# host information
+MINFO = 14	# mailbox or mail list information
+MX = 15		# mail exchange
+TXT = 16	# text strings
+
+# Additional TYPE values from host.c source
+
+UNAME = 110
+MP = 240
+
+# QTYPE values (section 3.2.3)
+
+AXFR = 252	# A request for a transfer of an entire zone
+MAILB = 253	# A request for mailbox-related records (MB, MG or MR)
+MAILA = 254	# A request for mail agent RRs (Obsolete - see MX)
+ANY = 255	# A request for all records
+
+# Construct reverse mapping dictionary
+
+_names = dir()
+typemap = {}
+for _name in _names:
+	if _name[0] != '_': typemap[eval(_name)] = _name
+
+def typestr(type):
+	if typemap.has_key(type): return typemap[type]
+	else: return `type`
diff --git a/Demo/embed/Makefile b/Demo/embed/Makefile
new file mode 100644
index 0000000..d63a9d4
--- /dev/null
+++ b/Demo/embed/Makefile
@@ -0,0 +1,42 @@
+# Makefile for embedded Python use demo
+
+# Top of the build tree and source tree
+blddir=		../..
+srcdir=		../..
+
+# Compiler flags
+OPT=		-g
+INCLUDES=	-I$(srcdir)/Include -I$(blddir)
+DEFINES=	-DHAVE_CONFIG_H
+CFLAGS=		$(OPT) $(DEFINES) $(INCLUDES)
+
+# Libraries
+# XXX edit MODLIBS, LIBS and SYSLIBS to match $(blddir)/Modules/Makefile
+MYLIBS=		$(blddir)/Modules/libModules.a \
+		$(blddir)/Python/libPython.a \
+		$(blddir)/Objects/libObjects.a \
+		$(blddir)/Parser/libParser.a
+MODLIBS=	
+LIBS=		
+SYSLIBS=	-lm
+ALLLIBS=	$(MYLIBS) $(MODLIBS) $(LIBS) $(SYSLIBS)
+
+# Build the demo application
+all:		demo
+demo:		demo.o config.o
+		$(CC) demo.o config.o $(ALLLIBS) -o demo
+
+# Build config.o, suppressing the main() function
+config.o:	$(blddir)/Modules/config.c
+		$(CC) $(CFLAGS) -DNO_MAIN -c $(blddir)/Modules/config.c
+
+# Administrative targets
+
+test:		demo
+		./demo
+
+clean:
+		-rm -f *.o core
+
+clobber:	clean
+		-rm -f *~ @* '#'* demo
diff --git a/Demo/embed/README b/Demo/embed/README
new file mode 100644
index 0000000..62b6513
--- /dev/null
+++ b/Demo/embed/README
@@ -0,0 +1,12 @@
+This directory show how easy it is to embed the Python interpreter in
+your own application.  The file demo.c shows you all that is needed in
+your C code.
+
+To build it, you may have to edit the Makefile:
+
+1) set blddir to the directory where you built Python, if it isn't in
+the source directory (../..)
+
+2) change the variables that together define the list of libraries
+(MODLIBS, LIBS, SYSLIBS) to link with, to match their definitions in
+$(blddir)/Modules/Makefile
diff --git a/Demo/embed/demo.c b/Demo/embed/demo.c
new file mode 100644
index 0000000..b1adde2
--- /dev/null
+++ b/Demo/embed/demo.c
@@ -0,0 +1,46 @@
+/* Example of embedding Python in another program */
+
+#include "allobjects.h"
+
+static char *argv0;
+
+main(argc, argv)
+	int argc;
+	char **argv;
+{
+	/* Save a copy of argv0 */
+	argv0 = argv[0];
+
+	/* Initialize the Python interpreter.  Required. */
+	initall();
+
+	/* Define sys.argv.  It is up to the application if you
+	   want this; you can also let it undefined (since the Python 
+	   code is generally not a main program it has no business
+	   touching sys.argv...) */
+	setpythonargv(argc, argv);
+
+	/* Do some application specific code */
+	printf("Hello, brave new world\n\n");
+
+	/* Execute some Python statements (in module __main__) */
+	run_command("import sys\n");
+	run_command("print sys.builtin_module_names\n");
+	run_command("print sys.argv\n");
+
+	/* Note that you can call any public function of the Python
+	   interpreter here, e.g. call_object(). */
+
+	/* Some more application specific code */
+	printf("\nGoodbye, cruel world\n");
+
+	/* Exit, cleaning up the interpreter */
+	goaway(0);
+	/*NOTREACHED*/
+}
+
+char *
+getprogramname()
+{
+	return argv0;
+}