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signalmodule.c

Last change on this file was 2, checked in by Yuri Dario, 15 years ago
Initial import for vendor code.
Property svn:eol-style set to `native`
File size: 22.3 KB

Line
1
2	/* Signal module -- many thanks to Lance Ellinghaus */
3
4	/* XXX Signals should be recorded per thread, now we have thread state. */
5
6	#include "Python.h"
7	#include "intrcheck.h"
8
9	#ifdef MS_WINDOWS
10	#include <process.h>
11	#endif
12
13	#include <signal.h>
14
15	#include <sys/stat.h>
16	#ifdef HAVE_SYS_TIME_H
17	#include <sys/time.h>
18	#endif
19
20	#ifndef SIG_ERR
21	#define SIG_ERR ((PyOS_sighandler_t)(-1))
22	#endif
23
24	#if defined(PYOS_OS2) && !defined(PYCC_GCC)
25	#define NSIG 12
26	#include <process.h>
27	#endif
28
29	#ifndef NSIG
30	# if defined(_NSIG)
31	# define NSIG _NSIG /* For BSD/SysV */
32	# elif defined(_SIGMAX)
33	# define NSIG (_SIGMAX + 1) /* For QNX */
34	# elif defined(SIGMAX)
35	# define NSIG (SIGMAX + 1) /* For djgpp */
36	# else
37	# define NSIG 64 /* Use a reasonable default value */
38	# endif
39	#endif
40
41
42	/*
43	NOTES ON THE INTERACTION BETWEEN SIGNALS AND THREADS
44
45	When threads are supported, we want the following semantics:
46
47	- only the main thread can set a signal handler
48	- any thread can get a signal handler
49	- signals are only delivered to the main thread
50
51	I.e. we don't support "synchronous signals" like SIGFPE (catching
52	this doesn't make much sense in Python anyway) nor do we support
53	signals as a means of inter-thread communication, since not all
54	thread implementations support that (at least our thread library
55	doesn't).
56
57	We still have the problem that in some implementations signals
58	generated by the keyboard (e.g. SIGINT) are delivered to all
59	threads (e.g. SGI), while in others (e.g. Solaris) such signals are
60	delivered to one random thread (an intermediate possibility would
61	be to deliver it to the main thread -- POSIX?). For now, we have
62	a working implementation that works in all three cases -- the
63	handler ignores signals if getpid() isn't the same as in the main
64	thread. XXX This is a hack.
65
66	GNU pth is a user-space threading library, and as such, all threads
67	run within the same process. In this case, if the currently running
68	thread is not the main_thread, send the signal to the main_thread.
69	*/
70
71	#ifdef WITH_THREAD
72	#include <sys/types.h> /* For pid_t */
73	#include "pythread.h"
74	static long main_thread;
75	static pid_t main_pid;
76	#endif
77
78	static struct {
79	int tripped;
80	PyObject *func;
81	} Handlers[NSIG];
82
83	static sig_atomic_t wakeup_fd = -1;
84
85	/* Speed up sigcheck() when none tripped */
86	static volatile sig_atomic_t is_tripped = 0;
87
88	static PyObject *DefaultHandler;
89	static PyObject *IgnoreHandler;
90	static PyObject *IntHandler;
91
92	/* On Solaris 8, gcc will produce a warning that the function
93	declaration is not a prototype. This is caused by the definition of
94	SIG_DFL as (void (*)())0; the correct declaration would have been
95	(void ()(int))0. /
96
97	static PyOS_sighandler_t old_siginthandler = SIG_DFL;
98
99	#ifdef HAVE_GETITIMER
100	static PyObject *ItimerError;
101
102	/* auxiliary functions for setitimer/getitimer */
103	static void
104	timeval_from_double(double d, struct timeval *tv)
105	{
106	tv->tv_sec = floor(d);
107	tv->tv_usec = fmod(d, 1.0) * 1000000.0;
108	}
109
110	Py_LOCAL_INLINE(double)
111	double_from_timeval(struct timeval *tv)
112	{
113	return tv->tv_sec + (double)(tv->tv_usec / 1000000.0);
114	}
115
116	static PyObject *
117	itimer_retval(struct itimerval *iv)
118	{
119	PyObject r, v;
120
121	r = PyTuple_New(2);
122	if (r == NULL)
123	return NULL;
124
125	if(!(v = PyFloat_FromDouble(double_from_timeval(&iv->it_value)))) {
126	Py_DECREF(r);
127	return NULL;
128	}
129
130	PyTuple_SET_ITEM(r, 0, v);
131
132	if(!(v = PyFloat_FromDouble(double_from_timeval(&iv->it_interval)))) {
133	Py_DECREF(r);
134	return NULL;
135	}
136
137	PyTuple_SET_ITEM(r, 1, v);
138
139	return r;
140	}
141	#endif
142
143	static PyObject *
144	signal_default_int_handler(PyObject self, PyObject args)
145	{
146	PyErr_SetNone(PyExc_KeyboardInterrupt);
147	return NULL;
148	}
149
150	PyDoc_STRVAR(default_int_handler_doc,
151	"default_int_handler(...)\n\
152	\n\
153	The default handler for SIGINT installed by Python.\n\
154	It raises KeyboardInterrupt.");
155
156
157	static int
158	checksignals_witharg(void * unused)
159	{
160	return PyErr_CheckSignals();
161	}
162
163	static void
164	signal_handler(int sig_num)
165	{
166	#ifdef WITH_THREAD
167	#ifdef WITH_PTH
168	if (PyThread_get_thread_ident() != main_thread) {
169	pth_raise((pth_t ) main_thread, sig_num);
170	return;
171	}
172	#endif
173	/* See NOTES section above */
174	if (getpid() == main_pid) {
175	#endif
176	Handlers[sig_num].tripped = 1;
177	/* Set is_tripped after setting .tripped, as it gets
178	cleared in PyErr_CheckSignals() before .tripped. */
179	is_tripped = 1;
180	Py_AddPendingCall(checksignals_witharg, NULL);
181	if (wakeup_fd != -1)
182	write(wakeup_fd, "\0", 1);
183	#ifdef WITH_THREAD
184	}
185	#endif
186	#ifdef SIGCHLD
187	if (sig_num == SIGCHLD) {
188	/* To avoid infinite recursion, this signal remains
189	reset until explicit re-instated.
190	Don't clear the 'func' field as it is our pointer
191	to the Python handler... */
192	return;
193	}
194	#endif
195	PyOS_setsig(sig_num, signal_handler);
196	}
197
198
199	#ifdef HAVE_ALARM
200	static PyObject *
201	signal_alarm(PyObject self, PyObject args)
202	{
203	int t;
204	if (!PyArg_ParseTuple(args, "i:alarm", &t))
205	return NULL;
206	/* alarm() returns the number of seconds remaining */
207	return PyInt_FromLong((long)alarm(t));
208	}
209
210	PyDoc_STRVAR(alarm_doc,
211	"alarm(seconds)\n\
212	\n\
213	Arrange for SIGALRM to arrive after the given number of seconds.");
214	#endif
215
216	#ifdef HAVE_PAUSE
217	static PyObject *
218	signal_pause(PyObject *self)
219	{
220	Py_BEGIN_ALLOW_THREADS
221	(void)pause();
222	Py_END_ALLOW_THREADS
223	/* make sure that any exceptions that got raised are propagated
224	* back into Python
225	*/
226	if (PyErr_CheckSignals())
227	return NULL;
228
229	Py_INCREF(Py_None);
230	return Py_None;
231	}
232	PyDoc_STRVAR(pause_doc,
233	"pause()\n\
234	\n\
235	Wait until a signal arrives.");
236
237	#endif
238
239
240	static PyObject *
241	signal_signal(PyObject self, PyObject args)
242	{
243	PyObject *obj;
244	int sig_num;
245	PyObject *old_handler;
246	void (*func)(int);
247	if (!PyArg_ParseTuple(args, "iO:signal", &sig_num, &obj))
248	return NULL;
249	#ifdef WITH_THREAD
250	if (PyThread_get_thread_ident() != main_thread) {
251	PyErr_SetString(PyExc_ValueError,
252	"signal only works in main thread");
253	return NULL;
254	}
255	#endif
256	if (sig_num < 1 \|\| sig_num >= NSIG) {
257	PyErr_SetString(PyExc_ValueError,
258	"signal number out of range");
259	return NULL;
260	}
261	if (obj == IgnoreHandler)
262	func = SIG_IGN;
263	else if (obj == DefaultHandler)
264	func = SIG_DFL;
265	else if (!PyCallable_Check(obj)) {
266	PyErr_SetString(PyExc_TypeError,
267	"signal handler must be signal.SIG_IGN, signal.SIG_DFL, or a callable object");
268	return NULL;
269	}
270	else
271	func = signal_handler;
272	if (PyOS_setsig(sig_num, func) == SIG_ERR) {
273	PyErr_SetFromErrno(PyExc_RuntimeError);
274	return NULL;
275	}
276	old_handler = Handlers[sig_num].func;
277	Handlers[sig_num].tripped = 0;
278	Py_INCREF(obj);
279	Handlers[sig_num].func = obj;
280	return old_handler;
281	}
282
283	PyDoc_STRVAR(signal_doc,
284	"signal(sig, action) -> action\n\
285	\n\
286	Set the action for the given signal. The action can be SIG_DFL,\n\
287	SIG_IGN, or a callable Python object. The previous action is\n\
288	returned. See getsignal() for possible return values.\n\
289	\n\
290	* IMPORTANT NOTICE *\n\
291	A signal handler function is called with two arguments:\n\
292	the first is the signal number, the second is the interrupted stack frame.");
293
294
295	static PyObject *
296	signal_getsignal(PyObject self, PyObject args)
297	{
298	int sig_num;
299	PyObject *old_handler;
300	if (!PyArg_ParseTuple(args, "i:getsignal", &sig_num))
301	return NULL;
302	if (sig_num < 1 \|\| sig_num >= NSIG) {
303	PyErr_SetString(PyExc_ValueError,
304	"signal number out of range");
305	return NULL;
306	}
307	old_handler = Handlers[sig_num].func;
308	Py_INCREF(old_handler);
309	return old_handler;
310	}
311
312	PyDoc_STRVAR(getsignal_doc,
313	"getsignal(sig) -> action\n\
314	\n\
315	Return the current action for the given signal. The return value can be:\n\
316	SIG_IGN -- if the signal is being ignored\n\
317	SIG_DFL -- if the default action for the signal is in effect\n\
318	None -- if an unknown handler is in effect\n\
319	anything else -- the callable Python object used as a handler");
320
321	#ifdef HAVE_SIGINTERRUPT
322	PyDoc_STRVAR(siginterrupt_doc,
323	"siginterrupt(sig, flag) -> None\n\
324	change system call restart behaviour: if flag is False, system calls\n\
325	will be restarted when interrupted by signal sig, else system calls\n\
326	will be interrupted.");
327
328	static PyObject *
329	signal_siginterrupt(PyObject self, PyObject args)
330	{
331	int sig_num;
332	int flag;
333
334	if (!PyArg_ParseTuple(args, "ii:siginterrupt", &sig_num, &flag))
335	return NULL;
336	if (sig_num < 1 \|\| sig_num >= NSIG) {
337	PyErr_SetString(PyExc_ValueError,
338	"signal number out of range");
339	return NULL;
340	}
341	if (siginterrupt(sig_num, flag)<0) {
342	PyErr_SetFromErrno(PyExc_RuntimeError);
343	return NULL;
344	}
345
346	Py_INCREF(Py_None);
347	return Py_None;
348	}
349
350	#endif
351
352	static PyObject *
353	signal_set_wakeup_fd(PyObject self, PyObject args)
354	{
355	struct stat buf;
356	int fd, old_fd;
357	if (!PyArg_ParseTuple(args, "i:set_wakeup_fd", &fd))
358	return NULL;
359	#ifdef WITH_THREAD
360	if (PyThread_get_thread_ident() != main_thread) {
361	PyErr_SetString(PyExc_ValueError,
362	"set_wakeup_fd only works in main thread");
363	return NULL;
364	}
365	#endif
366	if (fd != -1 && fstat(fd, &buf) != 0) {
367	PyErr_SetString(PyExc_ValueError, "invalid fd");
368	return NULL;
369	}
370	old_fd = wakeup_fd;
371	wakeup_fd = fd;
372	return PyLong_FromLong(old_fd);
373	}
374
375	PyDoc_STRVAR(set_wakeup_fd_doc,
376	"set_wakeup_fd(fd) -> fd\n\
377	\n\
378	Sets the fd to be written to (with '\\0') when a signal\n\
379	comes in. A library can use this to wakeup select or poll.\n\
380	The previous fd is returned.\n\
381	\n\
382	The fd must be non-blocking.");
383
384	/* C API for the same, without all the error checking */
385	int
386	PySignal_SetWakeupFd(int fd)
387	{
388	int old_fd = wakeup_fd;
389	if (fd < 0)
390	fd = -1;
391	wakeup_fd = fd;
392	return old_fd;
393	}
394
395
396	#ifdef HAVE_SETITIMER
397	static PyObject *
398	signal_setitimer(PyObject self, PyObject args)
399	{
400	double first;
401	double interval = 0;
402	int which;
403	struct itimerval new, old;
404
405	if(!PyArg_ParseTuple(args, "id\|d:setitimer", &which, &first, &interval))
406	return NULL;
407
408	timeval_from_double(first, &new.it_value);
409	timeval_from_double(interval, &new.it_interval);
410	/* Let OS check "which" value */
411	if (setitimer(which, &new, &old) != 0) {
412	PyErr_SetFromErrno(ItimerError);
413	return NULL;
414	}
415
416	return itimer_retval(&old);
417	}
418
419	PyDoc_STRVAR(setitimer_doc,
420	"setitimer(which, seconds[, interval])\n\
421	\n\
422	Sets given itimer (one of ITIMER_REAL, ITIMER_VIRTUAL\n\
423	or ITIMER_PROF) to fire after value seconds and after\n\
424	that every interval seconds.\n\
425	The itimer can be cleared by setting seconds to zero.\n\
426	\n\
427	Returns old values as a tuple: (delay, interval).");
428	#endif
429
430
431	#ifdef HAVE_GETITIMER
432	static PyObject *
433	signal_getitimer(PyObject self, PyObject args)
434	{
435	int which;
436	struct itimerval old;
437
438	if (!PyArg_ParseTuple(args, "i:getitimer", &which))
439	return NULL;
440
441	if (getitimer(which, &old) != 0) {
442	PyErr_SetFromErrno(ItimerError);
443	return NULL;
444	}
445
446	return itimer_retval(&old);
447	}
448
449	PyDoc_STRVAR(getitimer_doc,
450	"getitimer(which)\n\
451	\n\
452	Returns current value of given itimer.");
453	#endif
454
455
456	/* List of functions defined in the module */
457	static PyMethodDef signal_methods[] = {
458	#ifdef HAVE_ALARM
459	{"alarm", signal_alarm, METH_VARARGS, alarm_doc},
460	#endif
461	#ifdef HAVE_SETITIMER
462	{"setitimer", signal_setitimer, METH_VARARGS, setitimer_doc},
463	#endif
464	#ifdef HAVE_GETITIMER
465	{"getitimer", signal_getitimer, METH_VARARGS, getitimer_doc},
466	#endif
467	{"signal", signal_signal, METH_VARARGS, signal_doc},
468	{"getsignal", signal_getsignal, METH_VARARGS, getsignal_doc},
469	{"set_wakeup_fd", signal_set_wakeup_fd, METH_VARARGS, set_wakeup_fd_doc},
470	#ifdef HAVE_SIGINTERRUPT
471	{"siginterrupt", signal_siginterrupt, METH_VARARGS, siginterrupt_doc},
472	#endif
473	#ifdef HAVE_PAUSE
474	{"pause", (PyCFunction)signal_pause,
475	METH_NOARGS,pause_doc},
476	#endif
477	{"default_int_handler", signal_default_int_handler,
478	METH_VARARGS, default_int_handler_doc},
479	{NULL, NULL} /* sentinel */
480	};
481
482
483	PyDoc_STRVAR(module_doc,
484	"This module provides mechanisms to use signal handlers in Python.\n\
485	\n\
486	Functions:\n\
487	\n\
488	alarm() -- cause SIGALRM after a specified time [Unix only]\n\
489	setitimer() -- cause a signal (described below) after a specified\n\
490	float time and the timer may restart then [Unix only]\n\
491	getitimer() -- get current value of timer [Unix only]\n\
492	signal() -- set the action for a given signal\n\
493	getsignal() -- get the signal action for a given signal\n\
494	pause() -- wait until a signal arrives [Unix only]\n\
495	default_int_handler() -- default SIGINT handler\n\
496	\n\
497	signal constants:\n\
498	SIG_DFL -- used to refer to the system default handler\n\
499	SIG_IGN -- used to ignore the signal\n\
500	NSIG -- number of defined signals\n\
501	SIGINT, SIGTERM, etc. -- signal numbers\n\
502	\n\
503	itimer constants:\n\
504	ITIMER_REAL -- decrements in real time, and delivers SIGALRM upon\n\
505	expiration\n\
506	ITIMER_VIRTUAL -- decrements only when the process is executing,\n\
507	and delivers SIGVTALRM upon expiration\n\
508	ITIMER_PROF -- decrements both when the process is executing and\n\
509	when the system is executing on behalf of the process.\n\
510	Coupled with ITIMER_VIRTUAL, this timer is usually\n\
511	used to profile the time spent by the application\n\
512	in user and kernel space. SIGPROF is delivered upon\n\
513	expiration.\n\
514	\n\n\
515	* IMPORTANT NOTICE *\n\
516	A signal handler function is called with two arguments:\n\
517	the first is the signal number, the second is the interrupted stack frame.");
518
519	PyMODINIT_FUNC
520	initsignal(void)
521	{
522	PyObject m, d, *x;
523	int i;
524
525	#ifdef WITH_THREAD
526	main_thread = PyThread_get_thread_ident();
527	main_pid = getpid();
528	#endif
529
530	/* Create the module and add the functions */
531	m = Py_InitModule3("signal", signal_methods, module_doc);
532	if (m == NULL)
533	return;
534
535	/* Add some symbolic constants to the module */
536	d = PyModule_GetDict(m);
537
538	x = DefaultHandler = PyLong_FromVoidPtr((void *)SIG_DFL);
539	if (!x \|\| PyDict_SetItemString(d, "SIG_DFL", x) < 0)
540	goto finally;
541
542	x = IgnoreHandler = PyLong_FromVoidPtr((void *)SIG_IGN);
543	if (!x \|\| PyDict_SetItemString(d, "SIG_IGN", x) < 0)
544	goto finally;
545
546	x = PyInt_FromLong((long)NSIG);
547	if (!x \|\| PyDict_SetItemString(d, "NSIG", x) < 0)
548	goto finally;
549	Py_DECREF(x);
550
551	x = IntHandler = PyDict_GetItemString(d, "default_int_handler");
552	if (!x)
553	goto finally;
554	Py_INCREF(IntHandler);
555
556	Handlers[0].tripped = 0;
557	for (i = 1; i < NSIG; i++) {
558	void (*t)(int);
559	t = PyOS_getsig(i);
560	Handlers[i].tripped = 0;
561	if (t == SIG_DFL)
562	Handlers[i].func = DefaultHandler;
563	else if (t == SIG_IGN)
564	Handlers[i].func = IgnoreHandler;
565	else
566	Handlers[i].func = Py_None; /* None of our business */
567	Py_INCREF(Handlers[i].func);
568	}
569	if (Handlers[SIGINT].func == DefaultHandler) {
570	/* Install default int handler */
571	Py_INCREF(IntHandler);
572	Py_DECREF(Handlers[SIGINT].func);
573	Handlers[SIGINT].func = IntHandler;
574	old_siginthandler = PyOS_setsig(SIGINT, signal_handler);
575	}
576
577	#ifdef SIGHUP
578	x = PyInt_FromLong(SIGHUP);
579	PyDict_SetItemString(d, "SIGHUP", x);
580	Py_XDECREF(x);
581	#endif
582	#ifdef SIGINT
583	x = PyInt_FromLong(SIGINT);
584	PyDict_SetItemString(d, "SIGINT", x);
585	Py_XDECREF(x);
586	#endif
587	#ifdef SIGBREAK
588	x = PyInt_FromLong(SIGBREAK);
589	PyDict_SetItemString(d, "SIGBREAK", x);
590	Py_XDECREF(x);
591	#endif
592	#ifdef SIGQUIT
593	x = PyInt_FromLong(SIGQUIT);
594	PyDict_SetItemString(d, "SIGQUIT", x);
595	Py_XDECREF(x);
596	#endif
597	#ifdef SIGILL
598	x = PyInt_FromLong(SIGILL);
599	PyDict_SetItemString(d, "SIGILL", x);
600	Py_XDECREF(x);
601	#endif
602	#ifdef SIGTRAP
603	x = PyInt_FromLong(SIGTRAP);
604	PyDict_SetItemString(d, "SIGTRAP", x);
605	Py_XDECREF(x);
606	#endif
607	#ifdef SIGIOT
608	x = PyInt_FromLong(SIGIOT);
609	PyDict_SetItemString(d, "SIGIOT", x);
610	Py_XDECREF(x);
611	#endif
612	#ifdef SIGABRT
613	x = PyInt_FromLong(SIGABRT);
614	PyDict_SetItemString(d, "SIGABRT", x);
615	Py_XDECREF(x);
616	#endif
617	#ifdef SIGEMT
618	x = PyInt_FromLong(SIGEMT);
619	PyDict_SetItemString(d, "SIGEMT", x);
620	Py_XDECREF(x);
621	#endif
622	#ifdef SIGFPE
623	x = PyInt_FromLong(SIGFPE);
624	PyDict_SetItemString(d, "SIGFPE", x);
625	Py_XDECREF(x);
626	#endif
627	#ifdef SIGKILL
628	x = PyInt_FromLong(SIGKILL);
629	PyDict_SetItemString(d, "SIGKILL", x);
630	Py_XDECREF(x);
631	#endif
632	#ifdef SIGBUS
633	x = PyInt_FromLong(SIGBUS);
634	PyDict_SetItemString(d, "SIGBUS", x);
635	Py_XDECREF(x);
636	#endif
637	#ifdef SIGSEGV
638	x = PyInt_FromLong(SIGSEGV);
639	PyDict_SetItemString(d, "SIGSEGV", x);
640	Py_XDECREF(x);
641	#endif
642	#ifdef SIGSYS
643	x = PyInt_FromLong(SIGSYS);
644	PyDict_SetItemString(d, "SIGSYS", x);
645	Py_XDECREF(x);
646	#endif
647	#ifdef SIGPIPE
648	x = PyInt_FromLong(SIGPIPE);
649	PyDict_SetItemString(d, "SIGPIPE", x);
650	Py_XDECREF(x);
651	#endif
652	#ifdef SIGALRM
653	x = PyInt_FromLong(SIGALRM);
654	PyDict_SetItemString(d, "SIGALRM", x);
655	Py_XDECREF(x);
656	#endif
657	#ifdef SIGTERM
658	x = PyInt_FromLong(SIGTERM);
659	PyDict_SetItemString(d, "SIGTERM", x);
660	Py_XDECREF(x);
661	#endif
662	#ifdef SIGUSR1
663	x = PyInt_FromLong(SIGUSR1);
664	PyDict_SetItemString(d, "SIGUSR1", x);
665	Py_XDECREF(x);
666	#endif
667	#ifdef SIGUSR2
668	x = PyInt_FromLong(SIGUSR2);
669	PyDict_SetItemString(d, "SIGUSR2", x);
670	Py_XDECREF(x);
671	#endif
672	#ifdef SIGCLD
673	x = PyInt_FromLong(SIGCLD);
674	PyDict_SetItemString(d, "SIGCLD", x);
675	Py_XDECREF(x);
676	#endif
677	#ifdef SIGCHLD
678	x = PyInt_FromLong(SIGCHLD);
679	PyDict_SetItemString(d, "SIGCHLD", x);
680	Py_XDECREF(x);
681	#endif
682	#ifdef SIGPWR
683	x = PyInt_FromLong(SIGPWR);
684	PyDict_SetItemString(d, "SIGPWR", x);
685	Py_XDECREF(x);
686	#endif
687	#ifdef SIGIO
688	x = PyInt_FromLong(SIGIO);
689	PyDict_SetItemString(d, "SIGIO", x);
690	Py_XDECREF(x);
691	#endif
692	#ifdef SIGURG
693	x = PyInt_FromLong(SIGURG);
694	PyDict_SetItemString(d, "SIGURG", x);
695	Py_XDECREF(x);
696	#endif
697	#ifdef SIGWINCH
698	x = PyInt_FromLong(SIGWINCH);
699	PyDict_SetItemString(d, "SIGWINCH", x);
700	Py_XDECREF(x);
701	#endif
702	#ifdef SIGPOLL
703	x = PyInt_FromLong(SIGPOLL);
704	PyDict_SetItemString(d, "SIGPOLL", x);
705	Py_XDECREF(x);
706	#endif
707	#ifdef SIGSTOP
708	x = PyInt_FromLong(SIGSTOP);
709	PyDict_SetItemString(d, "SIGSTOP", x);
710	Py_XDECREF(x);
711	#endif
712	#ifdef SIGTSTP
713	x = PyInt_FromLong(SIGTSTP);
714	PyDict_SetItemString(d, "SIGTSTP", x);
715	Py_XDECREF(x);
716	#endif
717	#ifdef SIGCONT
718	x = PyInt_FromLong(SIGCONT);
719	PyDict_SetItemString(d, "SIGCONT", x);
720	Py_XDECREF(x);
721	#endif
722	#ifdef SIGTTIN
723	x = PyInt_FromLong(SIGTTIN);
724	PyDict_SetItemString(d, "SIGTTIN", x);
725	Py_XDECREF(x);
726	#endif
727	#ifdef SIGTTOU
728	x = PyInt_FromLong(SIGTTOU);
729	PyDict_SetItemString(d, "SIGTTOU", x);
730	Py_XDECREF(x);
731	#endif
732	#ifdef SIGVTALRM
733	x = PyInt_FromLong(SIGVTALRM);
734	PyDict_SetItemString(d, "SIGVTALRM", x);
735	Py_XDECREF(x);
736	#endif
737	#ifdef SIGPROF
738	x = PyInt_FromLong(SIGPROF);
739	PyDict_SetItemString(d, "SIGPROF", x);
740	Py_XDECREF(x);
741	#endif
742	#ifdef SIGXCPU
743	x = PyInt_FromLong(SIGXCPU);
744	PyDict_SetItemString(d, "SIGXCPU", x);
745	Py_XDECREF(x);
746	#endif
747	#ifdef SIGXFSZ
748	x = PyInt_FromLong(SIGXFSZ);
749	PyDict_SetItemString(d, "SIGXFSZ", x);
750	Py_XDECREF(x);
751	#endif
752	#ifdef SIGRTMIN
753	x = PyInt_FromLong(SIGRTMIN);
754	PyDict_SetItemString(d, "SIGRTMIN", x);
755	Py_XDECREF(x);
756	#endif
757	#ifdef SIGRTMAX
758	x = PyInt_FromLong(SIGRTMAX);
759	PyDict_SetItemString(d, "SIGRTMAX", x);
760	Py_XDECREF(x);
761	#endif
762	#ifdef SIGINFO
763	x = PyInt_FromLong(SIGINFO);
764	PyDict_SetItemString(d, "SIGINFO", x);
765	Py_XDECREF(x);
766	#endif
767
768	#ifdef ITIMER_REAL
769	x = PyLong_FromLong(ITIMER_REAL);
770	PyDict_SetItemString(d, "ITIMER_REAL", x);
771	Py_DECREF(x);
772	#endif
773	#ifdef ITIMER_VIRTUAL
774	x = PyLong_FromLong(ITIMER_VIRTUAL);
775	PyDict_SetItemString(d, "ITIMER_VIRTUAL", x);
776	Py_DECREF(x);
777	#endif
778	#ifdef ITIMER_PROF
779	x = PyLong_FromLong(ITIMER_PROF);
780	PyDict_SetItemString(d, "ITIMER_PROF", x);
781	Py_DECREF(x);
782	#endif
783
784	#if defined (HAVE_SETITIMER) \|\| defined (HAVE_GETITIMER)
785	ItimerError = PyErr_NewException("signal.ItimerError",
786	PyExc_IOError, NULL);
787	if (ItimerError != NULL)
788	PyDict_SetItemString(d, "ItimerError", ItimerError);
789	#endif
790
791	if (!PyErr_Occurred())
792	return;
793
794	/* Check for errors */
795	finally:
796	return;
797	}
798
799	static void
800	finisignal(void)
801	{
802	int i;
803	PyObject *func;
804
805	PyOS_setsig(SIGINT, old_siginthandler);
806	old_siginthandler = SIG_DFL;
807
808	for (i = 1; i < NSIG; i++) {
809	func = Handlers[i].func;
810	Handlers[i].tripped = 0;
811	Handlers[i].func = NULL;
812	if (i != SIGINT && func != NULL && func != Py_None &&
813	func != DefaultHandler && func != IgnoreHandler)
814	PyOS_setsig(i, SIG_DFL);
815	Py_XDECREF(func);
816	}
817
818	Py_XDECREF(IntHandler);
819	IntHandler = NULL;
820	Py_XDECREF(DefaultHandler);
821	DefaultHandler = NULL;
822	Py_XDECREF(IgnoreHandler);
823	IgnoreHandler = NULL;
824	}
825
826
827	/* Declared in pyerrors.h */
828	int
829	PyErr_CheckSignals(void)
830	{
831	int i;
832	PyObject *f;
833
834	if (!is_tripped)
835	return 0;
836
837	#ifdef WITH_THREAD
838	if (PyThread_get_thread_ident() != main_thread)
839	return 0;
840	#endif
841
842	/*
843	* The is_stripped variable is meant to speed up the calls to
844	* PyErr_CheckSignals (both directly or via pending calls) when no
845	* signal has arrived. This variable is set to 1 when a signal arrives
846	* and it is set to 0 here, when we know some signals arrived. This way
847	* we can run the registered handlers with no signals blocked.
848	*
849	* NOTE: with this approach we can have a situation where is_tripped is
850	* 1 but we have no more signals to handle (Handlers[i].tripped
851	* is 0 for every signal i). This won't do us any harm (except
852	* we're gonna spent some cycles for nothing). This happens when
853	* we receive a signal i after we zero is_tripped and before we
854	* check Handlers[i].tripped.
855	*/
856	is_tripped = 0;
857
858	if (!(f = (PyObject *)PyEval_GetFrame()))
859	f = Py_None;
860
861	for (i = 1; i < NSIG; i++) {
862	if (Handlers[i].tripped) {
863	PyObject *result = NULL;
864	PyObject *arglist = Py_BuildValue("(iO)", i, f);
865	Handlers[i].tripped = 0;
866
867	if (arglist) {
868	result = PyEval_CallObject(Handlers[i].func,
869	arglist);
870	Py_DECREF(arglist);
871	}
872	if (!result)
873	return -1;
874
875	Py_DECREF(result);
876	}
877	}
878
879	return 0;
880	}
881
882
883	/* Replacements for intrcheck.c functionality
884	* Declared in pyerrors.h
885	*/
886	void
887	PyErr_SetInterrupt(void)
888	{
889	is_tripped = 1;
890	Handlers[SIGINT].tripped = 1;
891	Py_AddPendingCall((int ()(void ))PyErr_CheckSignals, NULL);
892	}
893
894	void
895	PyOS_InitInterrupts(void)
896	{
897	initsignal();
898	_PyImport_FixupExtension("signal", "signal");
899	}
900
901	void
902	PyOS_FiniInterrupts(void)
903	{
904	finisignal();
905	}
906
907	int
908	PyOS_InterruptOccurred(void)
909	{
910	if (Handlers[SIGINT].tripped) {
911	#ifdef WITH_THREAD
912	if (PyThread_get_thread_ident() != main_thread)
913	return 0;
914	#endif
915	Handlers[SIGINT].tripped = 0;
916	return 1;
917	}
918	return 0;
919	}
920
921	void
922	PyOS_AfterFork(void)
923	{
924	#ifdef WITH_THREAD
925	PyEval_ReInitThreads();
926	main_thread = PyThread_get_thread_ident();
927	main_pid = getpid();
928	_PyImport_ReInitLock();
929	PyThread_ReInitTLS();
930	#endif
931	}

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source: python/vendor/Python-2.6.5/Modules/signalmodule.c

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