diff -ru Python-2.5.2-orig/Modules/signalmodule.c Python-2.5.2/Modules/signalmodule.c

--- Python-2.5.2-orig/Modules/signalmodule.c	2007-12-10 18:03:55.000000000 -0500

+++ Python-2.5.2/Modules/signalmodule.c	2008-09-24 17:32:45.000000000 -0400

@@ -12,6 +12,8 @@

 #include <signal.h>

+#include <sys/stat.h>

+

 #ifndef SIG_ERR

 #define SIG_ERR ((PyOS_sighandler_t)(-1))

 #endif

@@ -75,6 +77,8 @@

         PyObject *func;

 } Handlers[NSIG];

+static int wakeup_fd = -1;

+

 /* Speed up sigcheck() when none tripped */

 static volatile sig_atomic_t is_tripped = 0;

@@ -113,6 +117,7 @@

 static void

 signal_handler(int sig_num)

 {

+	const char dummy_byte = '\0';

 #ifdef WITH_THREAD

 #ifdef WITH_PTH

 	if (PyThread_get_thread_ident() != main_thread) {

@@ -128,6 +133,8 @@

                    cleared in PyErr_CheckSignals() before .tripped. */

 		is_tripped = 1;

 		Py_AddPendingCall(checksignals_witharg, NULL);

+		if (wakeup_fd != -1)

+			write(wakeup_fd, &dummy_byte, 1);

 #ifdef WITH_THREAD

 	}

 #endif

@@ -267,6 +274,39 @@

 anything else -- the callable Python object used as a handler");

+static PyObject *

+signal_set_wakeup_fd(PyObject *self, PyObject *args)

+{

+	struct stat buf;

+	int fd, old_fd;

+	if (!PyArg_ParseTuple(args, "i:set_wakeup_fd", &fd))

+		return NULL;

+#ifdef WITH_THREAD

+	if (PyThread_get_thread_ident() != main_thread) {

+		PyErr_SetString(PyExc_ValueError,

+				"set_wakeup_fd only works in main thread");

+		return NULL;

+	}

+#endif

+	if (fd != -1 && fstat(fd, &buf) != 0) {

+		PyErr_SetString(PyExc_ValueError, "invalid fd");

+		return NULL;

+	}

+	old_fd = wakeup_fd;

+	wakeup_fd = fd;

+	return PyLong_FromLong(old_fd);

+}

+

+PyDoc_STRVAR(set_wakeup_fd_doc,

+"set_wakeup_fd(fd) -> fd\n\

+\n\

+Sets the fd to be written to (with '\\0') when a signal\n\

+comes in.  A library can use this to wakeup select or poll.\n\

+The previous fd is returned.\n\

+\n\

+The fd must be non-blocking.");

+

+

 /* List of functions defined in the module */

 static PyMethodDef signal_methods[] = {

 #ifdef HAVE_ALARM

@@ -274,6 +314,7 @@

 #endif

 	{"signal",	        signal_signal, METH_VARARGS, signal_doc},

 	{"getsignal",	        signal_getsignal, METH_VARARGS, getsignal_doc},

+	{"set_wakeup_fd",	signal_set_wakeup_fd, METH_VARARGS, set_wakeup_fd_doc},

 #ifdef HAVE_PAUSE

 	{"pause",	        (PyCFunction)signal_pause,

 	 METH_NOARGS,pause_doc},