socketmodule.c

/* Socket module */

/* SSL support based on patches by Brian E Gallew and Laszlo Kovacs */

/*
This module provides an interface to Berkeley socket IPC.

Limitations:

- only AF_INET and AF_UNIX address families are supported
- no read/write operations (use send/recv or makefile instead)
- additional restrictions apply on Windows

Module interface:

- socket.error: exception raised for socket specific errors
- socket.gethostbyname(hostname) --> host IP address (string: 'dd.dd.dd.dd')
- socket.gethostbyaddr(IP address) --> (hostname, [alias, ...], [IP addr, ...])
- socket.gethostname() --> host name (string: 'spam' or 'spam.domain.com')
- socket.getprotobyname(protocolname) --> protocol number
- socket.getservbyname(servicename, protocolname) --> port number
- socket.socket(family, type [, proto]) --> new socket object
- socket.ntohs(16 bit value) --> new int object
- socket.ntohl(32 bit value) --> new int object
- socket.htons(16 bit value) --> new int object
- socket.htonl(32 bit value) --> new int object
- socket.AF_INET, socket.SOCK_STREAM, etc.: constants from <socket.h>
- socket.inet_aton(IP address) -> 32-bit packed IP representation
- socket.inet_ntoa(packed IP) -> IP address string
- socket.ssl(socket, keyfile, certfile) -> new ssl object
- an Internet socket address is a pair (hostname, port)
  where hostname can be anything recognized by gethostbyname()
  (including the dd.dd.dd.dd notation) and port is in host byte order
- where a hostname is returned, the dd.dd.dd.dd notation is used
- a UNIX domain socket address is a string specifying the pathname

Socket methods:

- s.accept() --> new socket object, sockaddr
- s.bind(sockaddr) --> None
- s.close() --> None
- s.connect(sockaddr) --> None
- s.connect_ex(sockaddr) --> 0 or errno (handy for e.g. async connect)
- s.fileno() --> file descriptor
- s.dup() --> same as socket.fromfd(os.dup(s.fileno(), ...)
- s.getpeername() --> sockaddr
- s.getsockname() --> sockaddr
- s.getsockopt(level, optname[, buflen]) --> int or string
- s.listen(backlog) --> None
- s.makefile([mode[, bufsize]]) --> file object
- s.recv(buflen [,flags]) --> string
- s.recvfrom(buflen [,flags]) --> string, sockaddr
- s.send(string [,flags]) --> nbytes
- s.sendto(string, [flags,] sockaddr) --> nbytes
- s.setblocking(0 | 1) --> None
- s.setsockopt(level, optname, value) --> None
- s.shutdown(how) --> None
- repr(s) --> "<socket object, fd=%d, family=%d, type=%d, protocol=%d>"

*/

#include "Python.h"

/* Hacks for gethostbyname_r().  On some non-Linux platforms, the configure
   script doesn't get this right, so we hardcode some platform checks below.
   On the other hand, not all Linux versions agree, so there the settings
   computed by the configure script are needed! */

#ifndef linux
#undef HAVE_GETHOSTBYNAME_R_3_ARG
#undef HAVE_GETHOSTBYNAME_R_5_ARG
#undef HAVE_GETHOSTBYNAME_R_6_ARG
#endif

#ifndef WITH_THREAD
#undef HAVE_GETHOSTBYNAME_R
#endif

#ifdef HAVE_GETHOSTBYNAME_R
#if defined(_AIX) || defined(__osf__)
#define HAVE_GETHOSTBYNAME_R_3_ARG
#elif defined(__sun__) || defined(__sgi)
#define HAVE_GETHOSTBYNAME_R_5_ARG
#elif defined(linux)
/* Rely on the configure script */
#else
#undef HAVE_GETHOSTBYNAME_R
#endif
#endif

#if !defined(HAVE_GETHOSTBYNAME_R) && defined(WITH_THREAD) && !defined(MS_WINDOWS)
#define USE_GETHOSTBYNAME_LOCK
#endif

#ifdef USE_GETHOSTBYNAME_LOCK
#include "pythread.h"
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#if defined(PYCC_VACPP)
#include <types.h>
#include <io.h>
#include <sys/ioctl.h>
#include <utils.h>
#include <ctype.h>
#endif

#if defined(PYOS_OS2)
#define  INCL_DOS
#define  INCL_DOSERRORS
#define  INCL_NOPMAPI
#include <os2.h>
#endif

#include <sys/types.h>

#include <signal.h>
#ifndef MS_WINDOWS
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#if !(defined(__BEOS__) || defined(__CYGWIN__))
#include <netinet/tcp.h>
#endif

/* Headers needed for inet_ntoa() and inet_addr() */
#ifdef __BEOS__
#include <net/netdb.h>
#else
#ifndef USE_GUSI1
#include <arpa/inet.h>
#endif
#endif

#include <fcntl.h>
#else
#include <winsock.h>
#include <fcntl.h>
#endif
#ifdef HAVE_SYS_UN_H
#include <sys/un.h>
#else
#undef AF_UNIX
#endif

#ifndef O_NDELAY
#define O_NDELAY O_NONBLOCK	/* For QNX only? */
#endif

#ifdef USE_GUSI1
/* fdopen() isn't declared in stdio.h (sigh) */
#include <GUSI.h>
#endif

#ifdef USE_SSL
#include "openssl/rsa.h"
#include "openssl/crypto.h"
#include "openssl/x509.h"
#include "openssl/pem.h"
#include "openssl/ssl.h"
#include "openssl/err.h"
#endif /* USE_SSL */

#if defined(MS_WINDOWS) || defined(__BEOS__)
/* BeOS suffers from the same socket dichotomy as Win32... - [cjh] */
/* seem to be a few differences in the API */
#define SOCKETCLOSE closesocket
#define NO_DUP /* Actually it exists on NT 3.5, but what the heck... */
#endif

/* abstract the socket file descriptor type */
#ifdef MS_WINDOWS
typedef SOCKET SOCKET_T;
#	ifdef MS_WIN64
#		define SIZEOF_SOCKET_T 8
#	else
#		define SIZEOF_SOCKET_T 4
#	endif
#else
typedef int SOCKET_T;
#	define SIZEOF_SOCKET_T SIZEOF_INT
#endif


#if defined(PYOS_OS2)
#define SOCKETCLOSE soclose
#define NO_DUP /* Sockets are Not Actual File Handles under OS/2 */
#endif

#ifndef SOCKETCLOSE
#define SOCKETCLOSE close
#endif

/* Global variable holding the exception type for errors detected
   by this module (but not argument type or memory errors, etc.). */

static PyObject *PySocket_Error;

#ifdef USE_SSL
static PyObject *SSLErrorObject;
#endif /* USE_SSL */


/* Convenience function to raise an error according to errno
   and return a NULL pointer from a function. */

static PyObject *
PySocket_Err(void)
{
#ifdef MS_WINDOWS
	int err_no = WSAGetLastError();
	if (err_no) {
		static struct { int no; const char *msg; } *msgp, msgs[] = {
			{ WSAEINTR, "Interrupted system call" },
			{ WSAEBADF, "Bad file descriptor" },
			{ WSAEACCES, "Permission denied" },
			{ WSAEFAULT, "Bad address" },
			{ WSAEINVAL, "Invalid argument" },
			{ WSAEMFILE, "Too many open files" },
			{ WSAEWOULDBLOCK, 
				"The socket operation could not complete "
				"without blocking" },
			{ WSAEINPROGRESS, "Operation now in progress" },
			{ WSAEALREADY, "Operation already in progress" },
			{ WSAENOTSOCK, "Socket operation on non-socket" },
			{ WSAEDESTADDRREQ, "Destination address required" },
			{ WSAEMSGSIZE, "Message too long" },
			{ WSAEPROTOTYPE, "Protocol wrong type for socket" },
			{ WSAENOPROTOOPT, "Protocol not available" },
			{ WSAEPROTONOSUPPORT, "Protocol not supported" },
			{ WSAESOCKTNOSUPPORT, "Socket type not supported" },
			{ WSAEOPNOTSUPP, "Operation not supported" },
			{ WSAEPFNOSUPPORT, "Protocol family not supported" },
			{ WSAEAFNOSUPPORT, "Address family not supported" },
			{ WSAEADDRINUSE, "Address already in use" },
			{ WSAEADDRNOTAVAIL,
				"Can't assign requested address" },
			{ WSAENETDOWN, "Network is down" },
			{ WSAENETUNREACH, "Network is unreachable" },
			{ WSAENETRESET, 
				"Network dropped connection on reset" },
			{ WSAECONNABORTED, 
				"Software caused connection abort" },
			{ WSAECONNRESET, "Connection reset by peer" },
			{ WSAENOBUFS, "No buffer space available" },
			{ WSAEISCONN, "Socket is already connected" },
			{ WSAENOTCONN, "Socket is not connected" },
			{ WSAESHUTDOWN, "Can't send after socket shutdown" },
			{ WSAETOOMANYREFS,
				"Too many references: can't splice" },
			{ WSAETIMEDOUT, "Operation timed out" },
			{ WSAECONNREFUSED, "Connection refused" },
			{ WSAELOOP, "Too many levels of symbolic links" },
			{ WSAENAMETOOLONG, "File name too long" },
			{ WSAEHOSTDOWN, "Host is down" },
			{ WSAEHOSTUNREACH, "No route to host" },
			{ WSAENOTEMPTY, "Directory not empty" },
			{ WSAEPROCLIM, "Too many processes" },
			{ WSAEUSERS, "Too many users" },
			{ WSAEDQUOT, "Disc quota exceeded" },
			{ WSAESTALE, "Stale NFS file handle" },
			{ WSAEREMOTE, "Too many levels of remote in path" },
			{ WSASYSNOTREADY,
				"Network subsystem is unvailable" },
			{ WSAVERNOTSUPPORTED,
				"WinSock version is not supported" },
			{ WSANOTINITIALISED, 
				"Successful WSAStartup() not yet performed" },
			{ WSAEDISCON, "Graceful shutdown in progress" },
			/* Resolver errors */
			{ WSAHOST_NOT_FOUND, "No such host is known" },
			{ WSATRY_AGAIN, "Host not found, or server failed" },
			{ WSANO_RECOVERY,
				"Unexpected server error encountered" },
			{ WSANO_DATA, "Valid name without requested data" },
			{ WSANO_ADDRESS, "No address, look for MX record" },
			{ 0, NULL }
		};
		PyObject *v;
		const char *msg = "winsock error";
		
		for (msgp = msgs; msgp->msg; msgp++) {
			if (err_no == msgp->no) {
				msg = msgp->msg;
				break;
			}
		}

		v = Py_BuildValue("(is)", err_no, msg);
		if (v != NULL) {
			PyErr_SetObject(PySocket_Error, v);
			Py_DECREF(v);
		}
		return NULL;
	}
	else
#endif

#if defined(PYOS_OS2)
    if (sock_errno() != NO_ERROR) {
        APIRET rc;
        ULONG  msglen;
        char   outbuf[100];
        int    myerrorcode = sock_errno();

        /* Retrieve Socket-Related Error Message from MPTN.MSG File */
        rc = DosGetMessage(NULL, 0, outbuf, sizeof(outbuf),
                           myerrorcode - SOCBASEERR + 26, "mptn.msg", &msglen);
        if (rc == NO_ERROR) {
            PyObject *v;

            outbuf[msglen] = '\0'; /* OS/2 Doesn't Guarantee a Terminator */
            if (strlen(outbuf) > 0) { /* If Non-Empty Msg, Trim CRLF */
                char *lastc = &outbuf[ strlen(outbuf)-1 ];
                while (lastc > outbuf && isspace(*lastc))
                    *lastc-- = '\0'; /* Trim Trailing Whitespace (CRLF) */
            }
            v = Py_BuildValue("(is)", myerrorcode, outbuf);
            if (v != NULL) {
                PyErr_SetObject(PySocket_Error, v);
                Py_DECREF(v);
            }
            return NULL;
        }
    }
#endif

	return PyErr_SetFromErrno(PySocket_Error);
}


/* The object holding a socket.  It holds some extra information,
   like the address family, which is used to decode socket address
   arguments properly. */

typedef struct {
	PyObject_HEAD
	SOCKET_T sock_fd;		/* Socket file descriptor */
	int sock_family;	/* Address family, e.g., AF_INET */
	int sock_type;		/* Socket type, e.g., SOCK_STREAM */
	int sock_proto;		/* Protocol type, usually 0 */
	union sock_addr {
		struct sockaddr_in in;
#ifdef AF_UNIX
		struct sockaddr_un un;
#endif
	} sock_addr;
} PySocketSockObject;

#ifdef USE_SSL

typedef struct {
	PyObject_HEAD
	PySocketSockObject *Socket;	/* Socket on which we're layered */
	PyObject 	*x_attr;	/* Attributes dictionary */
	SSL_CTX* 	ctx;
	SSL*     	ssl;
	X509*    	server_cert;
	BIO*		sbio;
	char    	server[256];
	char		issuer[256];

} SSLObject;

staticforward PyTypeObject SSL_Type;
staticforward PyObject *SSL_SSLwrite(SSLObject *self, PyObject *args);
staticforward PyObject *SSL_SSLread(SSLObject *self, PyObject *args);

#define SSLObject_Check(v)	((v)->ob_type == &SSL_Type)

#endif /* USE_SSL */
 
/* A forward reference to the Socktype type object.
   The Socktype variable contains pointers to various functions,
   some of which call newsockobject(), which uses Socktype, so
   there has to be a circular reference. */

staticforward PyTypeObject PySocketSock_Type;


/* Create a new socket object.
   This just creates the object and initializes it.
   If the creation fails, return NULL and set an exception (implicit
   in NEWOBJ()). */

static PySocketSockObject *
PySocketSock_New(SOCKET_T fd, int family, int type, int proto)
{
	PySocketSockObject *s;
	PySocketSock_Type.ob_type = &PyType_Type;
	s = PyObject_New(PySocketSockObject, &PySocketSock_Type);
	if (s != NULL) {
		s->sock_fd = fd;
		s->sock_family = family;
		s->sock_type = type;
		s->sock_proto = proto;
	}
	return s;
}


/* Lock to allow python interpreter to continue, but only allow one 
   thread to be in gethostbyname */
#ifdef USE_GETHOSTBYNAME_LOCK
PyThread_type_lock gethostbyname_lock;
#endif


/* Convert a string specifying a host name or one of a few symbolic
   names to a numeric IP address.  This usually calls gethostbyname()
   to do the work; the names "" and "<broadcast>" are special.
   Return the length (should always be 4 bytes), or negative if
   an error occurred; then an exception is raised. */

static int
setipaddr(char* name, struct sockaddr_in * addr_ret)
{
	struct hostent *hp;
	int d1, d2, d3, d4;
	int h_length;
	char ch;
#ifdef HAVE_GETHOSTBYNAME_R
	struct hostent hp_allocated;
#ifdef HAVE_GETHOSTBYNAME_R_3_ARG
	struct hostent_data data;
#else
	char buf[1001];
	int buf_len = (sizeof buf) - 1;
	int errnop;
#endif
#if defined(HAVE_GETHOSTBYNAME_R_3_ARG) || defined(HAVE_GETHOSTBYNAME_R_6_ARG)
	int result;
#endif
#endif /* HAVE_GETHOSTBYNAME_R */

	memset((void *) addr_ret, '\0', sizeof(*addr_ret));
	if (name[0] == '\0') {
		addr_ret->sin_addr.s_addr = INADDR_ANY;
		return 4;
	}
	if (name[0] == '<' && strcmp(name, "<broadcast>") == 0) {
		addr_ret->sin_addr.s_addr = INADDR_BROADCAST;
		return 4;
	}
	if (sscanf(name, "%d.%d.%d.%d%c", &d1, &d2, &d3, &d4, &ch) == 4 &&
	    0 <= d1 && d1 <= 255 && 0 <= d2 && d2 <= 255 &&
	    0 <= d3 && d3 <= 255 && 0 <= d4 && d4 <= 255) {
		addr_ret->sin_addr.s_addr = htonl(
			((long) d1 << 24) | ((long) d2 << 16) |
			((long) d3 << 8) | ((long) d4 << 0));
		return 4;
	}
	Py_BEGIN_ALLOW_THREADS
#ifdef HAVE_GETHOSTBYNAME_R
#if    defined(HAVE_GETHOSTBYNAME_R_6_ARG)
	result = gethostbyname_r(name, &hp_allocated, buf, buf_len, &hp, &errnop);
#elif  defined(HAVE_GETHOSTBYNAME_R_5_ARG)
	hp = gethostbyname_r(name, &hp_allocated, buf, buf_len, &errnop);
#else  /* HAVE_GETHOSTBYNAME_R_3_ARG */
	memset((void *) &data, '\0', sizeof(data));
	result = gethostbyname_r(name, &hp_allocated, &data);
	hp = (result != 0) ? NULL : &hp_allocated;
#endif
#else /* not HAVE_GETHOSTBYNAME_R */
#ifdef USE_GETHOSTBYNAME_LOCK
	PyThread_acquire_lock(gethostbyname_lock, 1);
#endif
	hp = gethostbyname(name);
#endif /* HAVE_GETHOSTBYNAME_R */
	Py_END_ALLOW_THREADS

	if (hp == NULL) {
#ifdef HAVE_HSTRERROR
	        /* Let's get real error message to return */
	        extern int h_errno;
		PyErr_SetString(PySocket_Error, (char *)hstrerror(h_errno));
#else
		PyErr_SetString(PySocket_Error, "host not found");
#endif
#ifdef USE_GETHOSTBYNAME_LOCK
		PyThread_release_lock(gethostbyname_lock);
#endif
		return -1;
	}
	memcpy((char *) &addr_ret->sin_addr, hp->h_addr, hp->h_length);
	h_length = hp->h_length;
#ifdef USE_GETHOSTBYNAME_LOCK
	PyThread_release_lock(gethostbyname_lock);
#endif
	return h_length;
}


/* Create a string object representing an IP address.
   This is always a string of the form 'dd.dd.dd.dd' (with variable
   size numbers). */

static PyObject *
makeipaddr(struct sockaddr_in *addr)
{
	long x = ntohl(addr->sin_addr.s_addr);
	char buf[100];
	sprintf(buf, "%d.%d.%d.%d",
		(int) (x>>24) & 0xff, (int) (x>>16) & 0xff,
		(int) (x>> 8) & 0xff, (int) (x>> 0) & 0xff);
	return PyString_FromString(buf);
}


/* Create an object representing the given socket address,
   suitable for passing it back to bind(), connect() etc.
   The family field of the sockaddr structure is inspected
   to determine what kind of address it really is. */

/*ARGSUSED*/
static PyObject *
makesockaddr(struct sockaddr *addr, int addrlen)
{
	if (addrlen == 0) {
		/* No address -- may be recvfrom() from known socket */
		Py_INCREF(Py_None);
		return Py_None;
	}

#ifdef __BEOS__
	/* XXX: BeOS version of accept() doesn't set family correctly */
	addr->sa_family = AF_INET;
#endif

	switch (addr->sa_family) {

	case AF_INET:
	{
		struct sockaddr_in *a = (struct sockaddr_in *) addr;
		PyObject *addrobj = makeipaddr(a);
		PyObject *ret = NULL;
		if (addrobj) {
			ret = Py_BuildValue("Oi", addrobj, ntohs(a->sin_port));
			Py_DECREF(addrobj);
		}
		return ret;
	}

#ifdef AF_UNIX
	case AF_UNIX:
	{
		struct sockaddr_un *a = (struct sockaddr_un *) addr;
		return PyString_FromString(a->sun_path);
	}
#endif /* AF_UNIX */

	/* More cases here... */

	default:
		/* If we don't know the address family, don't raise an
		   exception -- return it as a tuple. */
		return Py_BuildValue("is#",
				     addr->sa_family,
				     addr->sa_data,
				     sizeof(addr->sa_data));

	}
}


/* Parse a socket address argument according to the socket object's
   address family.  Return 1 if the address was in the proper format,
   0 of not.  The address is returned through addr_ret, its length
   through len_ret. */

static int
getsockaddrarg(PySocketSockObject *s, PyObject *args, struct sockaddr **addr_ret, int *len_ret)
{
	switch (s->sock_family) {

#ifdef AF_UNIX
	case AF_UNIX:
	{
		struct sockaddr_un* addr;
		char *path;
		int len;
		addr = (struct sockaddr_un* )&(s->sock_addr).un;
		if (!PyArg_Parse(args, "t#", &path, &len))
			return 0;
		if (len > sizeof addr->sun_path) {
			PyErr_SetString(PySocket_Error,
					"AF_UNIX path too long");
			return 0;
		}
		addr->sun_family = AF_UNIX;
		memcpy(addr->sun_path, path, len);
		addr->sun_path[len] = 0;
		*addr_ret = (struct sockaddr *) addr;
		*len_ret = len + sizeof(*addr) - sizeof(addr->sun_path);
		return 1;
	}
#endif /* AF_UNIX */

	case AF_INET:
	{
		struct sockaddr_in* addr;
		char *host;
		int port;
 		addr=(struct sockaddr_in*)&(s->sock_addr).in;
		if (!PyArg_Parse(args, "(si)", &host, &port))
			return 0;
		if (setipaddr(host, addr) < 0)
			return 0;
		addr->sin_family = AF_INET;
		addr->sin_port = htons((short)port);
		*addr_ret = (struct sockaddr *) addr;
		*len_ret = sizeof *addr;
		return 1;
	}

	/* More cases here... */

	default:
		PyErr_SetString(PySocket_Error, "getsockaddrarg: bad family");
		return 0;

	}
}


/* Get the address length according to the socket object's address family. 
   Return 1 if the family is known, 0 otherwise.  The length is returned
   through len_ret. */

static int
getsockaddrlen(PySocketSockObject *s, socklen_t *len_ret)
{
	switch (s->sock_family) {

#ifdef AF_UNIX
	case AF_UNIX:
	{
		*len_ret = sizeof (struct sockaddr_un);
		return 1;
	}
#endif /* AF_UNIX */

	case AF_INET:
	{
		*len_ret = sizeof (struct sockaddr_in);
		return 1;
	}

	/* More cases here... */

	default:
		PyErr_SetString(PySocket_Error, "getsockaddrlen: bad family");
		return 0;

	}
}


/* s.accept() method */

static PyObject *
PySocketSock_accept(PySocketSockObject *s, PyObject *args)
{
	char addrbuf[256];
	SOCKET_T newfd;
	socklen_t addrlen;
	PyObject *sock = NULL;
	PyObject *addr = NULL;
	PyObject *res = NULL;

	if (!PyArg_ParseTuple(args, ":accept"))
		return NULL;
	if (!getsockaddrlen(s, &addrlen))
		return NULL;
	Py_BEGIN_ALLOW_THREADS
	newfd = accept(s->sock_fd, (struct sockaddr *) addrbuf, &addrlen);
	Py_END_ALLOW_THREADS
#ifdef MS_WINDOWS
	if (newfd == INVALID_SOCKET)
#else
	if (newfd < 0)
#endif
		return PySocket_Err();

	/* Create the new object with unspecified family,
	   to avoid calls to bind() etc. on it. */
	sock = (PyObject *) PySocketSock_New(newfd,
					s->sock_family,
					s->sock_type,
					s->sock_proto);
	if (sock == NULL) {
		SOCKETCLOSE(newfd);
		goto finally;
	}
	if (!(addr = makesockaddr((struct sockaddr *) addrbuf, addrlen)))
		goto finally;

	if (!(res = Py_BuildValue("OO", sock, addr)))
		goto finally;

  finally:
	Py_XDECREF(sock);
	Py_XDECREF(addr);
	return res;
}

static char accept_doc[] =
"accept() -> (socket object, address info)\n\
\n\
Wait for an incoming connection.  Return a new socket representing the\n\
connection, and the address of the client.  For IP sockets, the address\n\
info is a pair (hostaddr, port).";


/* s.setblocking(1 | 0) method */

static PyObject *
PySocketSock_setblocking(PySocketSockObject *s, PyObject *args)
{
	int block;
#ifndef MS_WINDOWS
	int delay_flag;
#endif
	if (!PyArg_ParseTuple(args, "i:setblocking", &block))
		return NULL;
	Py_BEGIN_ALLOW_THREADS
#ifdef __BEOS__
	block = !block;
	setsockopt( s->sock_fd, SOL_SOCKET, SO_NONBLOCK,
				(void *)(&block), sizeof( int ) );
#else
#ifndef MS_WINDOWS
#ifdef PYOS_OS2
	block = !block;
	ioctl(s->sock_fd, FIONBIO, (caddr_t)&block, sizeof(block));
#else /* !PYOS_OS2 */
	delay_flag = fcntl (s->sock_fd, F_GETFL, 0);
	if (block)
		delay_flag &= (~O_NDELAY);
	else
		delay_flag |= O_NDELAY;
	fcntl (s->sock_fd, F_SETFL, delay_flag);
#endif /* !PYOS_OS2 */
#else /* MS_WINDOWS */
	block = !block;
	ioctlsocket(s->sock_fd, FIONBIO, (u_long*)&block);
#endif /* MS_WINDOWS */
#endif /* __BEOS__ */
	Py_END_ALLOW_THREADS

	Py_INCREF(Py_None);
	return Py_None;
}

static char setblocking_doc[] =
"setblocking(flag)\n\
\n\
Set the socket to blocking (flag is true) or non-blocking (false).\n\
This uses the FIONBIO ioctl with the O_NDELAY flag.";


/* s.setsockopt() method.
   With an integer third argument, sets an integer option.
   With a string third argument, sets an option from a buffer;
   use optional built-in module 'struct' to encode the string. */

static PyObject *
PySocketSock_setsockopt(PySocketSockObject *s, PyObject *args)
{
	int level;
	int optname;
	int res;
	char *buf;
	int buflen;
	int flag;

	if (PyArg_ParseTuple(args, "iii:setsockopt",
			     &level, &optname, &flag)) {
		buf = (char *) &flag;
		buflen = sizeof flag;
	}
	else {
		PyErr_Clear();
		if (!PyArg_ParseTuple(args, "iis#:setsockopt",
				      &level, &optname, &buf, &buflen))
			return NULL;
	}
	res = setsockopt(s->sock_fd, level, optname, (void *)buf, buflen);
	if (res < 0)
		return PySocket_Err();
	Py_INCREF(Py_None);
	return Py_None;
}

static char setsockopt_doc[] =
"setsockopt(level, option, value)\n\
\n\
Set a socket option.  See the Unix manual for level and option.\n\
The value argument can either be an integer or a string.";


/* s.getsockopt() method.
   With two arguments, retrieves an integer option.
   With a third integer argument, retrieves a string buffer of that size;
   use optional built-in module 'struct' to decode the string. */

static PyObject *
PySocketSock_getsockopt(PySocketSockObject *s, PyObject *args)
{
	int level;
	int optname;
	int res;
	PyObject *buf;
	socklen_t buflen = 0;

#ifdef __BEOS__
/* We have incomplete socket support. */
	PyErr_SetString( PySocket_Error, "getsockopt not supported" );
	return NULL;
#else

	if (!PyArg_ParseTuple(args, "ii|i:getsockopt",
			      &level, &optname, &buflen))
		return NULL;
	
	if (buflen == 0) {
		int flag = 0;
		socklen_t flagsize = sizeof flag;
		res = getsockopt(s->sock_fd, level, optname,
				 (void *)&flag, &flagsize);
		if (res < 0)
			return PySocket_Err();
		return PyInt_FromLong(flag);
	}
	if (buflen <= 0 || buflen > 1024) {
		PyErr_SetString(PySocket_Error,
				"getsockopt buflen out of range");
		return NULL;
	}
	buf = PyString_FromStringAndSize((char *)NULL, buflen);
	if (buf == NULL)
		return NULL;
	res = getsockopt(s->sock_fd, level, optname,
			 (void *)PyString_AsString(buf), &buflen);
	if (res < 0) {
		Py_DECREF(buf);
		return PySocket_Err();
	}
	_PyString_Resize(&buf, buflen);
	return buf;
#endif /* __BEOS__ */
}

static char getsockopt_doc[] =
"getsockopt(level, option[, buffersize]) -> value\n\
\n\
Get a socket option.  See the Unix manual for level and option.\n\
If a nonzero buffersize argument is given, the return value is a\n\
string of that length; otherwise it is an integer.";


/* s.bind(sockaddr) method */

static PyObject *
PySocketSock_bind(PySocketSockObject *s, PyObject *args)
{
	struct sockaddr *addr;
	int addrlen;
	int res;
	PyObject *addro;
	if (!PyArg_ParseTuple(args, "O:bind", &addro))
		return NULL;
	if (!getsockaddrarg(s, addro, &addr, &addrlen))
		return NULL;
	Py_BEGIN_ALLOW_THREADS
	res = bind(s->sock_fd, addr, addrlen);
	Py_END_ALLOW_THREADS
	if (res < 0)
		return PySocket_Err();
	Py_INCREF(Py_None);
	return Py_None;
}

static char bind_doc[] =
"bind(address)\n\
\n\
Bind the socket to a local address.  For IP sockets, the address is a\n\
pair (host, port); the host must refer to the local host.";


/* s.close() method.
   Set the file descriptor to -1 so operations tried subsequently
   will surely fail. */

static PyObject *
PySocketSock_close(PySocketSockObject *s, PyObject *args)
{
	SOCKET_T fd;
	if (!PyArg_ParseTuple(args, ":close"))
		return NULL;
	if ((fd = s->sock_fd) != -1) {
		s->sock_fd = -1;
		Py_BEGIN_ALLOW_THREADS
		(void) SOCKETCLOSE(fd);
		Py_END_ALLOW_THREADS
	}
	Py_INCREF(Py_None);
	return Py_None;
}

static char close_doc[] =
"close()\n\
\n\
Close the socket.  It cannot be used after this call.";


/* s.connect(sockaddr) method */

static PyObject *
PySocketSock_connect(PySocketSockObject *s, PyObject *args)
{
	struct sockaddr *addr;
	int addrlen;
	int res;
	PyObject *addro;
	if (!PyArg_ParseTuple(args, "O:connect", &addro))
		return NULL;
	if (!getsockaddrarg(s, addro, &addr, &addrlen))
		return NULL;
	Py_BEGIN_ALLOW_THREADS
	res = connect(s->sock_fd, addr, addrlen);
	Py_END_ALLOW_THREADS
	if (res < 0)
		return PySocket_Err();
	Py_INCREF(Py_None);
	return Py_None;
}

static char connect_doc[] =
"connect(address)\n\
\n\
Connect the socket to a remote address.  For IP sockets, the address\n\
is a pair (host, port).";


/* s.connect_ex(sockaddr) method */

static PyObject *
PySocketSock_connect_ex(PySocketSockObject *s, PyObject *args)
{
	struct sockaddr *addr;
	int addrlen;
	int res;
	PyObject *addro;
	if (!PyArg_ParseTuple(args, "O:connect_ex", &addro))
		return NULL;
	if (!getsockaddrarg(s, addro, &addr, &addrlen))
		return NULL;
	Py_BEGIN_ALLOW_THREADS
	res = connect(s->sock_fd, addr, addrlen);
	Py_END_ALLOW_THREADS
	if (res != 0)
		res = errno;
	return PyInt_FromLong((long) res);
}

static char connect_ex_doc[] =
"connect_ex(address)\n\
\n\
This is like connect(address), but returns an error code (the errno value)\n\
instead of raising an exception when an error occurs.";


/* s.fileno() method */

static PyObject *
PySocketSock_fileno(PySocketSockObject *s, PyObject *args)
{
	if (!PyArg_ParseTuple(args, ":fileno"))
		return NULL;
#if SIZEOF_SOCKET_T <= SIZEOF_LONG
	return PyInt_FromLong((long) s->sock_fd);
#else
	return PyLong_FromLongLong((LONG_LONG)s->sock_fd);
#endif
}

static char fileno_doc[] =
"fileno() -> integer\n\
\n\
Return the integer file descriptor of the socket.";


#ifndef NO_DUP
/* s.dup() method */

static PyObject *