New example of threaded embedding
diff --git a/Demo/pysvr/Makefile b/Demo/pysvr/Makefile
new file mode 100644
index 0000000..4adc2ce
--- /dev/null
+++ b/Demo/pysvr/Makefile
@@ -0,0 +1,49 @@
+# Makefile for 'pysvr' application embedding Python.
+# Tailored for Python 1.5a3 or later.
+# Some details are specific to Solaris or CNRI.
+
+# Which C compiler (only set because I don't have cc here)
+CC=gcc
+
+# Optimization preferences
+OPT=-g
+
+# Where Python is installed, and which version
+INST=/usr/local
+VER=1.5
+
+# Expressions using the above definitions -- no need to change
+PYVER=python$(VER)
+#PYC=$(INST)/lib/$(PYVER)/config
+PYC=../src/sparc
+PYINCL=-I$(INST)/include/$(PYVER) -I$(PYC)
+PYLIBS=$(PYC)/libpython1.5.a
+
+# Where GNU readline is installed
+RLINST=/depot/gnu/plat
+
+# Libraries to link with -- very installation dependent
+RLLIBS=-L$(RLINST)/lib -lreadline -ltermcap
+OTHERLIBS=-lsocket -lnsl -lpthread -ldl -lm
+
+# Compilation and link flags -- no need to change normally
+CFLAGS=$(PYINCL) $(OPT)
+LIBS=$(PYLIBS) $(RLLIBS) $(OTHERLIBS)
+
+# Default port for the pysvr application
+PORT=4000
+
+# Default target
+all: pysvr
+
+# Target to build pysvr
+pysvr: pysvr.o $(PYOBJS)
+	$(CC) pysvr.o $(LIBS) -o pysvr
+
+# Target to build and run pysvr
+run: pysvr
+	pysvr $(PORT)
+
+# Target to clean up the directory
+clean:
+	-rm -f pysvr *.o *~ core
diff --git a/Demo/pysvr/README b/Demo/pysvr/README
new file mode 100644
index 0000000..5e64e38
--- /dev/null
+++ b/Demo/pysvr/README
@@ -0,0 +1,9 @@
+This is an example of a multi-threaded C application embedding a
+Python interpreter.
+
+The particular application is a multi-threaded telnet-like server that
+provides you with a Python prompt (instead of a shell prompt).
+
+The file pysvr.py is a prototype in Python.
+
+THIS APPLICATION IS NOT SECURE -- ONLY USE IT FOR TESTING!
diff --git a/Demo/pysvr/pysvr.c b/Demo/pysvr/pysvr.c
new file mode 100644
index 0000000..f6f9e08
--- /dev/null
+++ b/Demo/pysvr/pysvr.c
@@ -0,0 +1,312 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <errno.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+
+#include <pthread.h>
+
+/* XXX Umpfh.
+   Python.h defines a typedef destructor, which conflicts with pthread.h.
+   So Python.h must be included after pthread.h. */
+
+#include <Python.h>
+
+#ifndef PORT
+#define PORT 4000
+#endif
+
+extern int optind;
+extern char *optarg;
+extern int getopt();
+
+struct workorder {
+	int conn;
+	struct sockaddr_in addr;
+};
+
+/* Forward */
+static void init_python(void);
+static void usage(void);
+static void oprogname(void);
+static void main_thread(int);
+static void create_thread(int, struct sockaddr_in *);
+static void *service_thread(struct workorder *);
+static void run_interpreter(FILE *, FILE *);
+static int run_command(char *, PyObject *);
+
+static char *progname = "pysvr";
+
+main(int argc, char **argv)
+{
+	int port = PORT;
+	int c;
+
+	if (argc > 0 && argv[0] != NULL && argv[0][0] != '\0')
+		progname = argv[0];
+
+	while ((c = getopt(argc, argv, "")) != EOF) {
+		switch (c) {
+		default:
+			usage();
+		}
+	}
+
+	if (optind < argc) {
+		if (optind+1 < argc) {
+			oprogname();
+			fprintf(stderr, "too many arguments\n");
+			usage();
+		}
+		port = atoi(argv[optind]);
+		if (port <= 0) {
+			fprintf(stderr, "bad port (%s)\n", argv[optind]);
+			usage();
+		}
+	}
+
+	main_thread(port);
+
+	fprintf(stderr, "Bye.\n");
+
+	exit(0);
+}
+
+static char usage_line[] = "usage: %s [port]\n";
+
+static void
+usage()
+{
+	fprintf(stderr, usage_line, progname);
+	exit(2);
+}
+
+static void
+main_thread(int port)
+{
+	int sock;
+	struct sockaddr_in addr;
+
+	sock = socket(PF_INET, SOCK_STREAM, 0);
+	if (sock < 0) {
+		oprogname();
+		perror("can't create socket");
+		exit(1);
+	}
+
+	memset(&addr, '\0', sizeof addr);
+	addr.sin_family = AF_INET;
+	addr.sin_port = htons(port);
+	addr.sin_addr.s_addr = 0L;
+	if (bind(sock, (struct sockaddr *)&addr, sizeof addr) < 0) {
+		oprogname();
+		perror("can't bind socket to address");
+		exit(1);
+	}
+
+	if (listen(sock, 5) < 0) {
+		oprogname();
+		perror("can't listen on socket");
+		exit(1);
+	}
+
+	fprintf(stderr, "Listening on port %d...\n", port);
+
+	for (;;) {
+		struct sockaddr_in clientaddr;
+		int conn, size;
+
+		conn = accept(sock, (struct sockaddr *) &clientaddr, &size);
+		if (conn < 0) {
+			oprogname();
+			perror("can't accept connection from socket");
+			exit(1);
+		}
+
+		create_thread(conn, &clientaddr);
+	}
+}
+
+static void
+create_thread(int conn, struct sockaddr_in *addr)
+{
+	struct workorder *work;
+	pthread_t tdata;
+
+	work = malloc(sizeof(struct workorder));
+	if (work == NULL) {
+		oprogname();
+		fprintf(stderr, "out of memory for thread.\n");
+		close(conn);
+		return;
+	}
+	work->conn = conn;
+	work->addr = *addr;
+
+	init_python();
+
+	if (pthread_create(&tdata, NULL, (void *)service_thread, work) < 0) {
+		oprogname();
+		perror("can't create new thread");
+		close(conn);
+		return;
+	}
+
+	if (pthread_detach(tdata) < 0) {
+		oprogname();
+		perror("can't detach from thread");
+	}
+}
+
+static PyThreadState *the_tstate;
+static PyInterpreterState *the_interp;
+static PyObject *the_builtins;
+
+static void
+init_python()
+{
+	if (the_interp)
+		return;
+	Py_Initialize(); /* Initialize the interpreter */
+	the_builtins = PyEval_GetBuiltins(); /* Get __builtins__ */
+	PyEval_InitThreads(); /* Create and acquire the interpreter lock */
+	the_tstate = PyEval_SaveThread(); /* Release lock & get thread state */
+	the_interp = the_tstate->interpreter_state; /* Get interp state */
+}
+
+static void *
+service_thread(struct workorder *work)
+{
+	FILE *input, *output;
+
+	fprintf(stderr, "Start thread for connection %d.\n", work->conn);
+
+	input = fdopen(work->conn, "r");
+	if (input == NULL) {
+		oprogname();
+		perror("can't create input stream");
+		goto done;
+	}
+
+	output = fdopen(work->conn, "w");
+	if (output == NULL) {
+		oprogname();
+		perror("can't create output stream");
+		fclose(input);
+		goto done;
+	}
+
+	setvbuf(input, NULL, _IONBF, 0);
+	setvbuf(output, NULL, _IONBF, 0);
+
+	run_interpreter(input, output);
+
+	fclose(input);
+	fclose(output);
+
+  done:
+	fprintf(stderr, "End thread for connection %d.\n", work->conn);
+	close(work->conn);
+	free(work);
+}
+
+static void
+oprogname()
+{
+	int save = errno;
+	fprintf(stderr, "%s: ", progname);
+	errno = save;
+}
+
+static void
+run_interpreter(FILE *input, FILE *output)
+{
+	PyThreadState *tstate;
+	PyObject *new_stdin, *new_stdout;
+	PyObject *old_stdin, *old_stdout, *old_stderr;
+	PyObject *globals;
+	char buffer[1000];
+	char *p, *q;
+	int n, end;
+
+	tstate = PyThreadState_New(the_interp);
+	PyEval_AcquireThread(tstate);
+
+	globals = PyDict_New();
+	PyDict_SetItemString(globals, "__builtins__", the_builtins);
+
+	new_stdin = PyFile_FromFile(input, "<socket-in>", "r", NULL);
+	new_stdout = PyFile_FromFile(output, "<socket-out>", "w", NULL);
+
+	old_stdin = PySys_GetObject("stdin");
+	old_stdout = PySys_GetObject("stdout");
+	old_stderr = PySys_GetObject("stderr");
+
+	for (n = 1; !PyErr_Occurred(); n++) {
+		Py_BEGIN_ALLOW_THREADS
+		fprintf(output, "%d> ", n);
+		p = fgets(buffer, sizeof buffer, input);
+		Py_END_ALLOW_THREADS
+
+		if (p == NULL)
+			break;
+		if (p[0] == '\377' && p[1] == '\354')
+			break;
+
+		q = strrchr(p, '\r');
+		if (q && q[1] == '\n' && q[2] == '\0') {
+			*q++ = '\n';
+			*q++ = '\0';
+		}
+
+		while (*p && isspace(*p))
+			p++;
+		if (p[0] == '#' || p[0] == '\0')
+			continue;
+
+		PySys_SetObject("stdin", new_stdin);
+		PySys_SetObject("stdout", new_stdout);
+		PySys_SetObject("stderr", new_stdout);
+
+		end = run_command(buffer, globals);
+		if (end < 0)
+			PyErr_Print();
+
+		PySys_SetObject("stdin", old_stdin);
+		PySys_SetObject("stdout", old_stdout);
+		PySys_SetObject("stderr", old_stderr);
+
+		if (end)
+			break;
+	}
+
+	Py_XDECREF(globals);
+	Py_XDECREF(new_stdin);
+	Py_XDECREF(new_stdout);
+
+	PyEval_ReleaseThread(tstate);
+	PyThreadState_Delete(tstate);
+
+	fprintf(output, "Goodbye!\n");
+}
+
+static int
+run_command(char *buffer, PyObject *globals)
+{
+	PyObject *m, *d, *v;
+	v = PyRun_String(buffer, Py_single_input, globals, globals);
+	if (v == NULL) {
+		if (PyErr_Occurred() == PyExc_SystemExit) {
+			PyErr_Clear();
+			return 1;
+		}
+		PyErr_Print();
+		return 0;
+	}
+	Py_DECREF(v);
+	return 0;
+}
diff --git a/Demo/pysvr/pysvr.py b/Demo/pysvr/pysvr.py
new file mode 100755
index 0000000..4488386
--- /dev/null
+++ b/Demo/pysvr/pysvr.py
@@ -0,0 +1,135 @@
+#! /usr/bin/env python
+
+"""A multi-threaded telnet-like server that gives a Python prompt.
+
+This is really a prototype for the same thing in C.
+
+Usage: pysvr.py [port]
+
+"""
+
+import sys, os, string, getopt, thread, socket, traceback
+
+OK_DOMAINS = [".cnri.reston.va.us", ".python.org"]
+
+PORT = 7585892 % 0xFFFF			# == 49367
+
+def main():
+    try:
+	opts, args = getopt.getopt(sys.argv[1:], "")
+	if len(args) > 1:
+	    raise getopt.error, "Too many arguments."
+    except getopt.error, msg:
+	usage(msg)
+    for o, a in opts:
+	pass
+    if args:
+	try:
+	    port = string.atoi(args[0])
+	except ValueError, msg:
+	    usage(msg)
+    else:
+	port = PORT
+    main_thread(port)
+
+def usage(msg=None):
+    sys.stdout = sys.stderr
+    if msg:
+	print msg
+    print "\n", __doc__,
+    sys.exit(2)
+
+def main_thread(port):
+    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    sock.bind(("", port))
+    sock.listen(5)
+    while 1:
+	(conn, addr) = sock.accept()
+	thread.start_new_thread(service_thread, (conn, addr))
+	del conn, addr
+
+def service_thread(conn, addr):
+    (caddr, cport) = addr
+    try:
+	host, aliases, ipaddrs = socket.gethostbyaddr(caddr)
+    except socket.error:
+	print "Don't know hostname for", caddr
+	return
+    if '.' not in host:
+	for a in aliases:
+	    if '.' in a:
+		host = a
+		break
+	else:
+	    print "Only a local name (%s) for %s" % (host, caddr)
+	    return
+    i = string.find(host, '.')
+    domain = string.lower(host[i:])
+    if domain not in OK_DOMAINS:
+	print "Connection from", host, "not accepted"
+	return
+    print "Thread %s has connection from %s.\n" % (str(thread.get_ident()),
+						   host),
+    stdin = conn.makefile("r")
+    stdout = conn.makefile("w", 0)
+    run_interpreter(stdin, stdout)
+    print "Thread %s is done.\n" % str(thread.get_ident()),
+
+def run_interpreter(stdin, stdout):
+    globals = {}
+    try:
+	str(sys.ps1)
+    except:
+	sys.ps1 = ">>> "
+    source = ""
+    while 1:
+	stdout.write(sys.ps1)
+	line = stdin.readline()
+	if line[:2] == '\377\354':
+	    line = ""
+	if not line and not source:
+	    break
+	if line[-2:] == '\r\n':
+	    line = line[:-2] + '\n'
+	source = source + line
+	try:
+	    code = compile_command(source)
+	except SyntaxError, err:
+	    source = ""
+	    traceback.print_exception(SyntaxError, err, None, file=stdout)
+	    continue
+	if not code:
+	    continue
+	source = ""
+	try:
+	    run_command(code, stdin, stdout, globals)
+	except SystemExit, how:
+	    if how:
+		try:
+		    how = str(how)
+		except:
+		    how = ""
+		stdout.write("Exit %s\n" % how)
+	    break
+    stdout.write("\nGoodbye.\n")
+
+def run_command(code, stdin, stdout, globals):
+	save = sys.stdin, sys.stdout, sys.stderr
+	try:
+	    sys.stdout = sys.stderr = stdout
+	    sys.stdin = stdin
+	    try:
+		exec code in globals
+	    except SystemExit, how:
+		raise SystemExit, how, sys.exc_info()[2]
+	    except:
+		type, value, tb = sys.exc_info()
+		if tb: tb = tb.tb_next
+		traceback.print_exception(type, value, tb)
+		del tb
+	finally:
+	    sys.stdin, sys.stdout, sys.stderr = save
+
+from code import compile_command
+
+main()