/* Signal module -- many thanks to Lance Ellinghaus */ /* XXX Signals should be recorded per thread, now we have thread state. */ #include "Python.h" #ifndef MS_WINDOWS #include "posixmodule.h" #endif #ifdef MS_WINDOWS #include "socketmodule.h" /* needed for SOCKET_T */ #endif #ifdef MS_WINDOWS #include #ifdef HAVE_PROCESS_H #include #endif #endif #ifdef HAVE_SIGNAL_H #include #endif #ifdef HAVE_SYS_STAT_H #include #endif #ifdef HAVE_SYS_TIME_H #include #endif #if defined(HAVE_PTHREAD_SIGMASK) && !defined(HAVE_BROKEN_PTHREAD_SIGMASK) # define PYPTHREAD_SIGMASK #endif #if defined(PYPTHREAD_SIGMASK) && defined(HAVE_PTHREAD_H) # include #endif #ifndef SIG_ERR #define SIG_ERR ((PyOS_sighandler_t)(-1)) #endif #ifndef NSIG # if defined(_NSIG) # define NSIG _NSIG /* For BSD/SysV */ # elif defined(_SIGMAX) # define NSIG (_SIGMAX + 1) /* For QNX */ # elif defined(SIGMAX) # define NSIG (SIGMAX + 1) /* For djgpp */ # else # define NSIG 64 /* Use a reasonable default value */ # endif #endif #include "clinic/signalmodule.c.h" /*[clinic input] module signal [clinic start generated code]*/ /*[clinic end generated code: output=da39a3ee5e6b4b0d input=b0301a3bde5fe9d3]*/ /* NOTES ON THE INTERACTION BETWEEN SIGNALS AND THREADS When threads are supported, we want the following semantics: - only the main thread can set a signal handler - any thread can get a signal handler - signals are only delivered to the main thread I.e. we don't support "synchronous signals" like SIGFPE (catching this doesn't make much sense in Python anyway) nor do we support signals as a means of inter-thread communication, since not all thread implementations support that (at least our thread library doesn't). We still have the problem that in some implementations signals generated by the keyboard (e.g. SIGINT) are delivered to all threads (e.g. SGI), while in others (e.g. Solaris) such signals are delivered to one random thread (an intermediate possibility would be to deliver it to the main thread -- POSIX?). For now, we have a working implementation that works in all three cases -- the handler ignores signals if getpid() isn't the same as in the main thread. XXX This is a hack. */ #ifdef WITH_THREAD #include /* For pid_t */ #include "pythread.h" static unsigned long main_thread; static pid_t main_pid; #endif static volatile struct { _Py_atomic_int tripped; PyObject *func; } Handlers[NSIG]; #ifdef MS_WINDOWS #define INVALID_FD ((SOCKET_T)-1) static volatile struct { SOCKET_T fd; int use_send; int send_err_set; int send_errno; int send_win_error; } wakeup = {INVALID_FD, 0, 0}; #else #define INVALID_FD (-1) static volatile sig_atomic_t wakeup_fd = -1; #endif /* Speed up sigcheck() when none tripped */ static _Py_atomic_int is_tripped; static PyObject *DefaultHandler; static PyObject *IgnoreHandler; static PyObject *IntHandler; /* On Solaris 8, gcc will produce a warning that the function declaration is not a prototype. This is caused by the definition of SIG_DFL as (void (*)())0; the correct declaration would have been (void (*)(int))0. */ static PyOS_sighandler_t old_siginthandler = SIG_DFL; #ifdef MS_WINDOWS static HANDLE sigint_event = NULL; #endif #ifdef HAVE_GETITIMER static PyObject *ItimerError; /* auxiliary functions for setitimer/getitimer */ static void timeval_from_double(double d, struct timeval *tv) { tv->tv_sec = floor(d); tv->tv_usec = fmod(d, 1.0) * 1000000.0; /* Don't disable the timer if the computation above rounds down to zero. */ if (d > 0.0 && tv->tv_sec == 0 && tv->tv_usec == 0) { tv->tv_usec = 1; } } Py_LOCAL_INLINE(double) double_from_timeval(struct timeval *tv) { return tv->tv_sec + (double)(tv->tv_usec / 1000000.0); } static PyObject * itimer_retval(struct itimerval *iv) { PyObject *r, *v; r = PyTuple_New(2); if (r == NULL) return NULL; if(!(v = PyFloat_FromDouble(double_from_timeval(&iv->it_value)))) { Py_DECREF(r); return NULL; } PyTuple_SET_ITEM(r, 0, v); if(!(v = PyFloat_FromDouble(double_from_timeval(&iv->it_interval)))) { Py_DECREF(r); return NULL; } PyTuple_SET_ITEM(r, 1, v); return r; } #endif static PyObject * signal_default_int_handler(PyObject *self, PyObject *args) { PyErr_SetNone(PyExc_KeyboardInterrupt); return NULL; } PyDoc_STRVAR(default_int_handler_doc, "default_int_handler(...)\n\ \n\ The default handler for SIGINT installed by Python.\n\ It raises KeyboardInterrupt."); static int report_wakeup_write_error(void *data) { int save_errno = errno; errno = (int) (intptr_t) data; PyErr_SetFromErrno(PyExc_OSError); PySys_WriteStderr("Exception ignored when trying to write to the " "signal wakeup fd:\n"); PyErr_WriteUnraisable(NULL); errno = save_errno; return 0; } #ifdef MS_WINDOWS static int report_wakeup_send_error(void* Py_UNUSED(data)) { PyObject *res; if (wakeup.send_win_error) { /* PyErr_SetExcFromWindowsErr() invokes FormatMessage() which recognizes the error codes used by both GetLastError() and WSAGetLastError */ res = PyErr_SetExcFromWindowsErr(PyExc_OSError, wakeup.send_win_error); } else { errno = wakeup.send_errno; res = PyErr_SetFromErrno(PyExc_OSError); } assert(res == NULL); wakeup.send_err_set = 0; PySys_WriteStderr("Exception ignored when trying to send to the " "signal wakeup fd:\n"); PyErr_WriteUnraisable(NULL); return 0; } #endif /* MS_WINDOWS */ static void trip_signal(int sig_num) { unsigned char byte; int fd; Py_ssize_t rc; _Py_atomic_store_relaxed(&Handlers[sig_num].tripped, 1); /* Set is_tripped after setting .tripped, as it gets cleared in PyErr_CheckSignals() before .tripped. */ _Py_atomic_store(&is_tripped, 1); /* Notify ceval.c */ _PyEval_SignalReceived(); /* And then write to the wakeup fd *after* setting all the globals and doing the _PyEval_SignalReceived. We used to write to the wakeup fd and then set the flag, but this allowed the following sequence of events (especially on windows, where trip_signal may run in a new thread): - main thread blocks on select([wakeup_fd], ...) - signal arrives - trip_signal writes to the wakeup fd - the main thread wakes up - the main thread checks the signal flags, sees that they're unset - the main thread empties the wakeup fd - the main thread goes back to sleep - trip_signal sets the flags to request the Python-level signal handler be run - the main thread doesn't notice, because it's asleep See bpo-30038 for more details. */ #ifdef MS_WINDOWS fd = Py_SAFE_DOWNCAST(wakeup.fd, SOCKET_T, int); #else fd = wakeup_fd; #endif if (fd != INVALID_FD) { byte = (unsigned char)sig_num; #ifdef MS_WINDOWS if (wakeup.use_send) { do { rc = send(fd, &byte, 1, 0); } while (rc < 0 && errno == EINTR); /* we only have a storage for one error in the wakeup structure */ if (rc < 0 && !wakeup.send_err_set) { wakeup.send_err_set = 1; wakeup.send_errno = errno; wakeup.send_win_error = GetLastError(); /* Py_AddPendingCall() isn't signal-safe, but we still use it for this exceptional case. */ Py_AddPendingCall(report_wakeup_send_error, NULL); } } else #endif { byte = (unsigned char)sig_num; /* _Py_write_noraise() retries write() if write() is interrupted by a signal (fails with EINTR). */ rc = _Py_write_noraise(fd, &byte, 1); if (rc < 0) { /* Py_AddPendingCall() isn't signal-safe, but we still use it for this exceptional case. */ Py_AddPendingCall(report_wakeup_write_error, (void *)(intptr_t)errno); } } } } static void signal_handler(int sig_num) { int save_errno = errno; #ifdef WITH_THREAD /* See NOTES section above */ if (getpid() == main_pid) #endif { trip_signal(sig_num); } #ifndef HAVE_SIGACTION #ifdef SIGCHLD /* To avoid infinite recursion, this signal remains reset until explicit re-instated. Don't clear the 'func' field as it is our pointer to the Python handler... */ if (sig_num != SIGCHLD) #endif /* If the handler was not set up with sigaction, reinstall it. See * Python/pylifecycle.c for the implementation of PyOS_setsig which * makes this true. See also issue8354. */ PyOS_setsig(sig_num, signal_handler); #endif /* Issue #10311: asynchronously executing signal handlers should not mutate errno under the feet of unsuspecting C code. */ errno = save_errno; #ifdef MS_WINDOWS if (sig_num == SIGINT) SetEvent(sigint_event); #endif } #ifdef HAVE_ALARM /*[clinic input] signal.alarm -> long seconds: int / Arrange for SIGALRM to arrive after the given number of seconds. [clinic start generated code]*/ static long signal_alarm_impl(PyObject *module, int seconds) /*[clinic end generated code: output=144232290814c298 input=0d5e97e0e6f39e86]*/ { /* alarm() returns the number of seconds remaining */ return (long)alarm(seconds); } #endif #ifdef HAVE_PAUSE /*[clinic input] signal.pause Wait until a signal arrives. [clinic start generated code]*/ static PyObject * signal_pause_impl(PyObject *module) /*[clinic end generated code: output=391656788b3c3929 input=f03de0f875752062]*/ { Py_BEGIN_ALLOW_THREADS (void)pause(); Py_END_ALLOW_THREADS /* make sure that any exceptions that got raised are propagated * back into Python */ if (PyErr_CheckSignals()) return NULL; Py_RETURN_NONE; } #endif /*[clinic input] signal.signal signalnum: int handler: object / Set the action for the given signal. The action can be SIG_DFL, SIG_IGN, or a callable Python object. The previous action is returned. See getsignal() for possible return values. *** IMPORTANT NOTICE *** A signal handler function is called with two arguments: the first is the signal number, the second is the interrupted stack frame. [clinic start generated code]*/ static PyObject * signal_signal_impl(PyObject *module, int signalnum, PyObject *handler) /*[clinic end generated code: output=b44cfda43780f3a1 input=deee84af5fa0432c]*/ { PyObject *old_handler; void (*func)(int); #ifdef MS_WINDOWS /* Validate that signalnum is one of the allowable signals */ switch (signalnum) { case SIGABRT: break; #ifdef SIGBREAK /* Issue #10003: SIGBREAK is not documented as permitted, but works and corresponds to CTRL_BREAK_EVENT. */ case SIGBREAK: break; #endif case SIGFPE: break; case SIGILL: break; case SIGINT: break; case SIGSEGV: break; case SIGTERM: break; default: PyErr_SetString(PyExc_ValueError, "invalid signal value"); return NULL; } #endif #ifdef WITH_THREAD if (PyThread_get_thread_ident() != main_thread) { PyErr_SetString(PyExc_ValueError, "signal only works in main thread"); return NULL; } #endif if (signalnum < 1 || signalnum >= NSIG) { PyErr_SetString(PyExc_ValueError, "signal number out of range"); return NULL; } if (handler == IgnoreHandler) func = SIG_IGN; else if (handler == DefaultHandler) func = SIG_DFL; else if (!PyCallable_Check(handler)) { PyErr_SetString(PyExc_TypeError, "signal handler must be signal.SIG_IGN, signal.SIG_DFL, or a callable object"); return NULL; } else func = signal_handler; if (PyOS_setsig(signalnum, func) == SIG_ERR) { PyErr_SetFromErrno(PyExc_OSError); return NULL; } old_handler = Handlers[signalnum].func; _Py_atomic_store_relaxed(&Handlers[signalnum].tripped, 0); Py_INCREF(handler); Handlers[signalnum].func = handler; if (old_handler != NULL) return old_handler; else Py_RETURN_NONE; } /*[clinic input] signal.getsignal signalnum: int / Return the current action for the given signal. The return value can be: SIG_IGN -- if the signal is being ignored SIG_DFL -- if the default action for the signal is in effect None -- if an unknown handler is in effect anything else -- the callable Python object used as a handler [clinic start generated code]*/ static PyObject * signal_getsignal_impl(PyObject *module, int signalnum) /*[clinic end generated code: output=35b3e0e796fd555e input=ac23a00f19dfa509]*/ { PyObject *old_handler; if (signalnum < 1 || signalnum >= NSIG) { PyErr_SetString(PyExc_ValueError, "signal number out of range"); return NULL; } old_handler = Handlers[signalnum].func; if (old_handler != NULL) { Py_INCREF(old_handler); return old_handler; } else { Py_RETURN_NONE; } } #ifdef HAVE_SIGINTERRUPT /*[clinic input] signal.siginterrupt signalnum: int flag: int / Change system call restart behaviour. If flag is False, system calls will be restarted when interrupted by signal sig, else system calls will be interrupted. [clinic start generated code]*/ static PyObject * signal_siginterrupt_impl(PyObject *module, int signalnum, int flag) /*[clinic end generated code: output=063816243d85dd19 input=4160acacca3e2099]*/ { if (signalnum < 1 || signalnum >= NSIG) { PyErr_SetString(PyExc_ValueError, "signal number out of range"); return NULL; } if (siginterrupt(signalnum, flag)<0) { PyErr_SetFromErrno(PyExc_OSError); return NULL; } Py_RETURN_NONE; } #endif static PyObject* signal_set_wakeup_fd(PyObject *self, PyObject *args) { struct _Py_stat_struct status; #ifdef MS_WINDOWS PyObject *fdobj; SOCKET_T sockfd, old_sockfd; int res; int res_size = sizeof res; PyObject *mod; int is_socket; if (!PyArg_ParseTuple(args, "O:set_wakeup_fd", &fdobj)) return NULL; sockfd = PyLong_AsSocket_t(fdobj); if (sockfd == (SOCKET_T)(-1) && PyErr_Occurred()) return NULL; #else int fd, old_fd; if (!PyArg_ParseTuple(args, "i:set_wakeup_fd", &fd)) return NULL; #endif #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 #ifdef MS_WINDOWS is_socket = 0; if (sockfd != INVALID_FD) { /* Import the _socket module to call WSAStartup() */ mod = PyImport_ImportModuleNoBlock("_socket"); if (mod == NULL) return NULL; Py_DECREF(mod); /* test the socket */ if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, (char *)&res, &res_size) != 0) { int fd, err; err = WSAGetLastError(); if (err != WSAENOTSOCK) { PyErr_SetExcFromWindowsErr(PyExc_OSError, err); return NULL; } fd = (int)sockfd; if ((SOCKET_T)fd != sockfd) { PyErr_SetString(PyExc_ValueError, "invalid fd"); return NULL; } if (_Py_fstat(fd, &status) != 0) return NULL; /* on Windows, a file cannot be set to non-blocking mode */ } else { is_socket = 1; /* Windows does not provide a function to test if a socket is in non-blocking mode */ } } old_sockfd = wakeup.fd; wakeup.fd = sockfd; wakeup.use_send = is_socket; if (old_sockfd != INVALID_FD) return PyLong_FromSocket_t(old_sockfd); else return PyLong_FromLong(-1); #else if (fd != -1) { int blocking; if (_Py_fstat(fd, &status) != 0) return NULL; blocking = _Py_get_blocking(fd); if (blocking < 0) return NULL; if (blocking) { PyErr_Format(PyExc_ValueError, "the fd %i must be in non-blocking mode", fd); return NULL; } } old_fd = wakeup_fd; wakeup_fd = fd; return PyLong_FromLong(old_fd); #endif } PyDoc_STRVAR(set_wakeup_fd_doc, "set_wakeup_fd(fd) -> fd\n\ \n\ Sets the fd to be written to (with the signal number) when a signal\n\ comes in. A library can use this to wakeup select or poll.\n\ The previous fd or -1 is returned.\n\ \n\ The fd must be non-blocking."); /* C API for the same, without all the error checking */ int PySignal_SetWakeupFd(int fd) { int old_fd; if (fd < 0) fd = -1; #ifdef MS_WINDOWS old_fd = Py_SAFE_DOWNCAST(wakeup.fd, SOCKET_T, int); wakeup.fd = fd; #else old_fd = wakeup_fd; wakeup_fd = fd; #endif return old_fd; } #ifdef HAVE_SETITIMER /*[clinic input] signal.setitimer which: int seconds: double interval: double = 0.0 / Sets given itimer (one of ITIMER_REAL, ITIMER_VIRTUAL or ITIMER_PROF). The timer will fire after value seconds and after that every interval seconds. The itimer can be cleared by setting seconds to zero. Returns old values as a tuple: (delay, interval). [clinic start generated code]*/ static PyObject * signal_setitimer_impl(PyObject *module, int which, double seconds, double interval) /*[clinic end generated code: output=6f51da0fe0787f2c input=0d27d417cfcbd51a]*/ { struct itimerval new, old; timeval_from_double(seconds, &new.it_value); timeval_from_double(interval, &new.it_interval); /* Let OS check "which" value */ if (setitimer(which, &new, &old) != 0) { PyErr_SetFromErrno(ItimerError); return NULL; } return itimer_retval(&old); } #endif #ifdef HAVE_GETITIMER /*[clinic input] signal.getitimer which: int / Returns current value of given itimer. [clinic start generated code]*/ static PyObject * signal_getitimer_impl(PyObject *module, int which) /*[clinic end generated code: output=9e053175d517db40 input=f7d21d38f3490627]*/ { struct itimerval old; if (getitimer(which, &old) != 0) { PyErr_SetFromErrno(ItimerError); return NULL; } return itimer_retval(&old); } #endif #if defined(PYPTHREAD_SIGMASK) || defined(HAVE_SIGWAIT) || \ defined(HAVE_SIGWAITINFO) || defined(HAVE_SIGTIMEDWAIT) /* Convert an iterable to a sigset. Return 0 on success, return -1 and raise an exception on error. */ static int iterable_to_sigset(PyObject *iterable, sigset_t *mask) { int result = -1; PyObject *iterator, *item; long signum; int err; sigemptyset(mask); iterator = PyObject_GetIter(iterable); if (iterator == NULL) goto error; while (1) { item = PyIter_Next(iterator); if (item == NULL) { if (PyErr_Occurred()) goto error; else break; } signum = PyLong_AsLong(item); Py_DECREF(item); if (signum == -1 && PyErr_Occurred()) goto error; if (0 < signum && signum < NSIG) err = sigaddset(mask, (int)signum); else err = 1; if (err) { PyErr_Format(PyExc_ValueError, "signal number %ld out of range", signum); goto error; } } result = 0; error: Py_XDECREF(iterator); return result; } #endif #if defined(PYPTHREAD_SIGMASK) || defined(HAVE_SIGPENDING) static PyObject* sigset_to_set(sigset_t mask) { PyObject *signum, *result; int sig; result = PySet_New(0); if (result == NULL) return NULL; for (sig = 1; sig < NSIG; sig++) { if (sigismember(&mask, sig) != 1) continue; /* Handle the case where it is a member by adding the signal to the result list. Ignore the other cases because they mean the signal isn't a member of the mask or the signal was invalid, and an invalid signal must have been our fault in constructing the loop boundaries. */ signum = PyLong_FromLong(sig); if (signum == NULL) { Py_DECREF(result); return NULL; } if (PySet_Add(result, signum) == -1) { Py_DECREF(signum); Py_DECREF(result); return NULL; } Py_DECREF(signum); } return result; } #endif #ifdef PYPTHREAD_SIGMASK /*[clinic input] signal.pthread_sigmask how: int mask: object / Fetch and/or change the signal mask of the calling thread. [clinic start generated code]*/ static PyObject * signal_pthread_sigmask_impl(PyObject *module, int how, PyObject *mask) /*[clinic end generated code: output=ff640fe092bc9181 input=f3b7d7a61b7b8283]*/ { sigset_t newmask, previous; int err; if (iterable_to_sigset(mask, &newmask)) return NULL; err = pthread_sigmask(how, &newmask, &previous); if (err != 0) { errno = err; PyErr_SetFromErrno(PyExc_OSError); return NULL; } /* if signals was unblocked, signal handlers have been called */ if (PyErr_CheckSignals()) return NULL; return sigset_to_set(previous); } #endif /* #ifdef PYPTHREAD_SIGMASK */ #ifdef HAVE_SIGPENDING /*[clinic input] signal.sigpending Examine pending signals. Returns a set of signal numbers that are pending for delivery to the calling thread. [clinic start generated code]*/ static PyObject * signal_sigpending_impl(PyObject *module) /*[clinic end generated code: output=53375ffe89325022 input=e0036c016f874e29]*/ { int err; sigset_t mask; err = sigpending(&mask); if (err) return PyErr_SetFromErrno(PyExc_OSError); return sigset_to_set(mask); } #endif /* #ifdef HAVE_SIGPENDING */ #ifdef HAVE_SIGWAIT /*[clinic input] signal.sigwait sigset: object / Wait for a signal. Suspend execution of the calling thread until the delivery of one of the signals specified in the signal set sigset. The function accepts the signal and returns the signal number. [clinic start generated code]*/ static PyObject * signal_sigwait(PyObject *module, PyObject *sigset) /*[clinic end generated code: output=557173647424f6e4 input=11af2d82d83c2e94]*/ { sigset_t set; int err, signum; if (iterable_to_sigset(sigset, &set)) return NULL; Py_BEGIN_ALLOW_THREADS err = sigwait(&set, &signum); Py_END_ALLOW_THREADS if (err) { errno = err; return PyErr_SetFromErrno(PyExc_OSError); } return PyLong_FromLong(signum); } #endif /* #ifdef HAVE_SIGWAIT */ #if defined(HAVE_SIGWAITINFO) || defined(HAVE_SIGTIMEDWAIT) static int initialized; static PyStructSequence_Field struct_siginfo_fields[] = { {"si_signo", "signal number"}, {"si_code", "signal code"}, {"si_errno", "errno associated with this signal"}, {"si_pid", "sending process ID"}, {"si_uid", "real user ID of sending process"}, {"si_status", "exit value or signal"}, {"si_band", "band event for SIGPOLL"}, {0} }; PyDoc_STRVAR(struct_siginfo__doc__, "struct_siginfo: Result from sigwaitinfo or sigtimedwait.\n\n\ This object may be accessed either as a tuple of\n\ (si_signo, si_code, si_errno, si_pid, si_uid, si_status, si_band),\n\ or via the attributes si_signo, si_code, and so on."); static PyStructSequence_Desc struct_siginfo_desc = { "signal.struct_siginfo", /* name */ struct_siginfo__doc__, /* doc */ struct_siginfo_fields, /* fields */ 7 /* n_in_sequence */ }; static PyTypeObject SiginfoType; static PyObject * fill_siginfo(siginfo_t *si) { PyObject *result = PyStructSequence_New(&SiginfoType); if (!result) return NULL; PyStructSequence_SET_ITEM(result, 0, PyLong_FromLong((long)(si->si_signo))); PyStructSequence_SET_ITEM(result, 1, PyLong_FromLong((long)(si->si_code))); PyStructSequence_SET_ITEM(result, 2, PyLong_FromLong((long)(si->si_errno))); PyStructSequence_SET_ITEM(result, 3, PyLong_FromPid(si->si_pid)); PyStructSequence_SET_ITEM(result, 4, _PyLong_FromUid(si->si_uid)); PyStructSequence_SET_ITEM(result, 5, PyLong_FromLong((long)(si->si_status))); #ifdef HAVE_SIGINFO_T_SI_BAND PyStructSequence_SET_ITEM(result, 6, PyLong_FromLong(si->si_band)); #else PyStructSequence_SET_ITEM(result, 6, PyLong_FromLong(0L)); #endif if (PyErr_Occurred()) { Py_DECREF(result); return NULL; } return result; } #endif #ifdef HAVE_SIGWAITINFO /*[clinic input] signal.sigwaitinfo sigset: object / Wait synchronously until one of the signals in *sigset* is delivered. Returns a struct_siginfo containing information about the signal. [clinic start generated code]*/ static PyObject * signal_sigwaitinfo(PyObject *module, PyObject *sigset) /*[clinic end generated code: output=c40f27b269cd2309 input=f3779a74a991e171]*/ { sigset_t set; siginfo_t si; int err; int async_err = 0; if (iterable_to_sigset(sigset, &set)) return NULL; do { Py_BEGIN_ALLOW_THREADS err = sigwaitinfo(&set, &si); Py_END_ALLOW_THREADS } while (err == -1 && errno == EINTR && !(async_err = PyErr_CheckSignals())); if (err == -1) return (!async_err) ? PyErr_SetFromErrno(PyExc_OSError) : NULL; return fill_siginfo(&si); } #endif /* #ifdef HAVE_SIGWAITINFO */ #ifdef HAVE_SIGTIMEDWAIT /*[clinic input] signal.sigtimedwait sigset: object timeout as timeout_obj: object / Like sigwaitinfo(), but with a timeout. The timeout is specified in seconds, with floating point numbers allowed. [clinic start generated code]*/ static PyObject * signal_sigtimedwait_impl(PyObject *module, PyObject *sigset, PyObject *timeout_obj) /*[clinic end generated code: output=f7eff31e679f4312 input=53fd4ea3e3724eb8]*/ { struct timespec ts; sigset_t set; siginfo_t si; int res; _PyTime_t timeout, deadline, monotonic; if (_PyTime_FromSecondsObject(&timeout, timeout_obj, _PyTime_ROUND_CEILING) < 0) return NULL; if (timeout < 0) { PyErr_SetString(PyExc_ValueError, "timeout must be non-negative"); return NULL; } if (iterable_to_sigset(sigset, &set)) return NULL; deadline = _PyTime_GetMonotonicClock() + timeout; do { if (_PyTime_AsTimespec(timeout, &ts) < 0) return NULL; Py_BEGIN_ALLOW_THREADS res = sigtimedwait(&set, &si, &ts); Py_END_ALLOW_THREADS if (res != -1) break; if (errno != EINTR) { if (errno == EAGAIN) Py_RETURN_NONE; else return PyErr_SetFromErrno(PyExc_OSError); } /* sigtimedwait() was interrupted by a signal (EINTR) */ if (PyErr_CheckSignals()) return NULL; monotonic = _PyTime_GetMonotonicClock(); timeout = deadline - monotonic; if (timeout < 0) break; } while (1); return fill_siginfo(&si); } #endif /* #ifdef HAVE_SIGTIMEDWAIT */ #if defined(HAVE_PTHREAD_KILL) && defined(WITH_THREAD) /*[clinic input] signal.pthread_kill thread_id: unsigned_long(bitwise=True) signalnum: int / Send a signal to a thread. [clinic start generated code]*/ static PyObject * signal_pthread_kill_impl(PyObject *module, unsigned long thread_id, int signalnum) /*[clinic end generated code: output=7629919b791bc27f input=1d901f2c7bb544ff]*/ { int err; err = pthread_kill((pthread_t)thread_id, signalnum); if (err != 0) { errno = err; PyErr_SetFromErrno(PyExc_OSError); return NULL; } /* the signal may have been send to the current thread */ if (PyErr_CheckSignals()) return NULL; Py_RETURN_NONE; } #endif /* #if defined(HAVE_PTHREAD_KILL) && defined(WITH_THREAD) */ /* List of functions defined in the module -- some of the methoddefs are defined to nothing if the corresponding C function is not available. */ static PyMethodDef signal_methods[] = { {"default_int_handler", signal_default_int_handler, METH_VARARGS, default_int_handler_doc}, SIGNAL_ALARM_METHODDEF SIGNAL_SETITIMER_METHODDEF SIGNAL_GETITIMER_METHODDEF SIGNAL_SIGNAL_METHODDEF SIGNAL_GETSIGNAL_METHODDEF {"set_wakeup_fd", signal_set_wakeup_fd, METH_VARARGS, set_wakeup_fd_doc}, SIGNAL_SIGINTERRUPT_METHODDEF SIGNAL_PAUSE_METHODDEF SIGNAL_PTHREAD_KILL_METHODDEF SIGNAL_PTHREAD_SIGMASK_METHODDEF SIGNAL_SIGPENDING_METHODDEF SIGNAL_SIGWAIT_METHODDEF SIGNAL_SIGWAITINFO_METHODDEF SIGNAL_SIGTIMEDWAIT_METHODDEF {NULL, NULL} /* sentinel */ }; PyDoc_STRVAR(module_doc, "This module provides mechanisms to use signal handlers in Python.\n\ \n\ Functions:\n\ \n\ alarm() -- cause SIGALRM after a specified time [Unix only]\n\ setitimer() -- cause a signal (described below) after a specified\n\ float time and the timer may restart then [Unix only]\n\ getitimer() -- get current value of timer [Unix only]\n\ signal() -- set the action for a given signal\n\ getsignal() -- get the signal action for a given signal\n\ pause() -- wait until a signal arrives [Unix only]\n\ default_int_handler() -- default SIGINT handler\n\ \n\ signal constants:\n\ SIG_DFL -- used to refer to the system default handler\n\ SIG_IGN -- used to ignore the signal\n\ NSIG -- number of defined signals\n\ SIGINT, SIGTERM, etc. -- signal numbers\n\ \n\ itimer constants:\n\ ITIMER_REAL -- decrements in real time, and delivers SIGALRM upon\n\ expiration\n\ ITIMER_VIRTUAL -- decrements only when the process is executing,\n\ and delivers SIGVTALRM upon expiration\n\ ITIMER_PROF -- decrements both when the process is executing and\n\ when the system is executing on behalf of the process.\n\ Coupled with ITIMER_VIRTUAL, this timer is usually\n\ used to profile the time spent by the application\n\ in user and kernel space. SIGPROF is delivered upon\n\ expiration.\n\ \n\n\ *** IMPORTANT NOTICE ***\n\ A signal handler function is called with two arguments:\n\ the first is the signal number, the second is the interrupted stack frame."); static struct PyModuleDef signalmodule = { PyModuleDef_HEAD_INIT, "_signal", module_doc, -1, signal_methods, NULL, NULL, NULL, NULL }; PyMODINIT_FUNC PyInit__signal(void) { PyObject *m, *d, *x; int i; #ifdef WITH_THREAD main_thread = PyThread_get_thread_ident(); main_pid = getpid(); #endif /* Create the module and add the functions */ m = PyModule_Create(&signalmodule); if (m == NULL) return NULL; #if defined(HAVE_SIGWAITINFO) || defined(HAVE_SIGTIMEDWAIT) if (!initialized) { if (PyStructSequence_InitType2(&SiginfoType, &struct_siginfo_desc) < 0) return NULL; } Py_INCREF((PyObject*) &SiginfoType); PyModule_AddObject(m, "struct_siginfo", (PyObject*) &SiginfoType); initialized = 1; #endif /* Add some symbolic constants to the module */ d = PyModule_GetDict(m); x = DefaultHandler = PyLong_FromVoidPtr((void *)SIG_DFL); if (!x || PyDict_SetItemString(d, "SIG_DFL", x) < 0) goto finally; x = IgnoreHandler = PyLong_FromVoidPtr((void *)SIG_IGN); if (!x || PyDict_SetItemString(d, "SIG_IGN", x) < 0) goto finally; x = PyLong_FromLong((long)NSIG); if (!x || PyDict_SetItemString(d, "NSIG", x) < 0) goto finally; Py_DECREF(x); #ifdef SIG_BLOCK if (PyModule_AddIntMacro(m, SIG_BLOCK)) goto finally; #endif #ifdef SIG_UNBLOCK if (PyModule_AddIntMacro(m, SIG_UNBLOCK)) goto finally; #endif #ifdef SIG_SETMASK if (PyModule_AddIntMacro(m, SIG_SETMASK)) goto finally; #endif x = IntHandler = PyDict_GetItemString(d, "default_int_handler"); if (!x) goto finally; Py_INCREF(IntHandler); _Py_atomic_store_relaxed(&Handlers[0].tripped, 0); for (i = 1; i < NSIG; i++) { void (*t)(int); t = PyOS_getsig(i); _Py_atomic_store_relaxed(&Handlers[i].tripped, 0); if (t == SIG_DFL) Handlers[i].func = DefaultHandler; else if (t == SIG_IGN) Handlers[i].func = IgnoreHandler; else Handlers[i].func = Py_None; /* None of our business */ Py_INCREF(Handlers[i].func); } if (Handlers[SIGINT].func == DefaultHandler) { /* Install default int handler */ Py_INCREF(IntHandler); Py_SETREF(Handlers[SIGINT].func, IntHandler); old_siginthandler = PyOS_setsig(SIGINT, signal_handler); } #ifdef SIGHUP if (PyModule_AddIntMacro(m, SIGHUP)) goto finally; #endif #ifdef SIGINT if (PyModule_AddIntMacro(m, SIGINT)) goto finally; #endif #ifdef SIGBREAK if (PyModule_AddIntMacro(m, SIGBREAK)) goto finally; #endif #ifdef SIGQUIT if (PyModule_AddIntMacro(m, SIGQUIT)) goto finally; #endif #ifdef SIGILL if (PyModule_AddIntMacro(m, SIGILL)) goto finally; #endif #ifdef SIGTRAP if (PyModule_AddIntMacro(m, SIGTRAP)) goto finally; #endif #ifdef SIGIOT if (PyModule_AddIntMacro(m, SIGIOT)) goto finally; #endif #ifdef SIGABRT if (PyModule_AddIntMacro(m, SIGABRT)) goto finally; #endif #ifdef SIGEMT if (PyModule_AddIntMacro(m, SIGEMT)) goto finally; #endif #ifdef SIGFPE if (PyModule_AddIntMacro(m, SIGFPE)) goto finally; #endif #ifdef SIGKILL if (PyModule_AddIntMacro(m, SIGKILL)) goto finally; #endif #ifdef SIGBUS if (PyModule_AddIntMacro(m, SIGBUS)) goto finally; #endif #ifdef SIGSEGV if (PyModule_AddIntMacro(m, SIGSEGV)) goto finally; #endif #ifdef SIGSYS if (PyModule_AddIntMacro(m, SIGSYS)) goto finally; #endif #ifdef SIGPIPE if (PyModule_AddIntMacro(m, SIGPIPE)) goto finally; #endif #ifdef SIGALRM if (PyModule_AddIntMacro(m, SIGALRM)) goto finally; #endif #ifdef SIGTERM if (PyModule_AddIntMacro(m, SIGTERM)) goto finally; #endif #ifdef SIGUSR1 if (PyModule_AddIntMacro(m, SIGUSR1)) goto finally; #endif #ifdef SIGUSR2 if (PyModule_AddIntMacro(m, SIGUSR2)) goto finally; #endif #ifdef SIGCLD if (PyModule_AddIntMacro(m, SIGCLD)) goto finally; #endif #ifdef SIGCHLD if (PyModule_AddIntMacro(m, SIGCHLD)) goto finally; #endif #ifdef SIGPWR if (PyModule_AddIntMacro(m, SIGPWR)) goto finally; #endif #ifdef SIGIO if (PyModule_AddIntMacro(m, SIGIO)) goto finally; #endif #ifdef SIGURG if (PyModule_AddIntMacro(m, SIGURG)) goto finally; #endif #ifdef SIGWINCH if (PyModule_AddIntMacro(m, SIGWINCH)) goto finally; #endif #ifdef SIGPOLL if (PyModule_AddIntMacro(m, SIGPOLL)) goto finally; #endif #ifdef SIGSTOP if (PyModule_AddIntMacro(m, SIGSTOP)) goto finally; #endif #ifdef SIGTSTP if (PyModule_AddIntMacro(m, SIGTSTP)) goto finally; #endif #ifdef SIGCONT if (PyModule_AddIntMacro(m, SIGCONT)) goto finally; #endif #ifdef SIGTTIN if (PyModule_AddIntMacro(m, SIGTTIN)) goto finally; #endif #ifdef SIGTTOU if (PyModule_AddIntMacro(m, SIGTTOU)) goto finally; #endif #ifdef SIGVTALRM if (PyModule_AddIntMacro(m, SIGVTALRM)) goto finally; #endif #ifdef SIGPROF if (PyModule_AddIntMacro(m, SIGPROF)) goto finally; #endif #ifdef SIGXCPU if (PyModule_AddIntMacro(m, SIGXCPU)) goto finally; #endif #ifdef SIGXFSZ if (PyModule_AddIntMacro(m, SIGXFSZ)) goto finally; #endif #ifdef SIGRTMIN if (PyModule_AddIntMacro(m, SIGRTMIN)) goto finally; #endif #ifdef SIGRTMAX if (PyModule_AddIntMacro(m, SIGRTMAX)) goto finally; #endif #ifdef SIGINFO if (PyModule_AddIntMacro(m, SIGINFO)) goto finally; #endif #ifdef ITIMER_REAL if (PyModule_AddIntMacro(m, ITIMER_REAL)) goto finally; #endif #ifdef ITIMER_VIRTUAL if (PyModule_AddIntMacro(m, ITIMER_VIRTUAL)) goto finally; #endif #ifdef ITIMER_PROF if (PyModule_AddIntMacro(m, ITIMER_PROF)) goto finally; #endif #if defined (HAVE_SETITIMER) || defined (HAVE_GETITIMER) ItimerError = PyErr_NewException("signal.ItimerError", PyExc_OSError, NULL); if (ItimerError != NULL) PyDict_SetItemString(d, "ItimerError", ItimerError); #endif #ifdef CTRL_C_EVENT if (PyModule_AddIntMacro(m, CTRL_C_EVENT)) goto finally; #endif #ifdef CTRL_BREAK_EVENT if (PyModule_AddIntMacro(m, CTRL_BREAK_EVENT)) goto finally; #endif #ifdef MS_WINDOWS /* Create manual-reset event, initially unset */ sigint_event = CreateEvent(NULL, TRUE, FALSE, FALSE); #endif if (PyErr_Occurred()) { Py_DECREF(m); m = NULL; } finally: return m; } static void finisignal(void) { int i; PyObject *func; PyOS_setsig(SIGINT, old_siginthandler); old_siginthandler = SIG_DFL; for (i = 1; i < NSIG; i++) { func = Handlers[i].func; _Py_atomic_store_relaxed(&Handlers[i].tripped, 0); Handlers[i].func = NULL; if (i != SIGINT && func != NULL && func != Py_None && func != DefaultHandler && func != IgnoreHandler) PyOS_setsig(i, SIG_DFL); Py_XDECREF(func); } Py_CLEAR(IntHandler); Py_CLEAR(DefaultHandler); Py_CLEAR(IgnoreHandler); } /* Declared in pyerrors.h */ int PyErr_CheckSignals(void) { int i; PyObject *f; if (!_Py_atomic_load(&is_tripped)) return 0; #ifdef WITH_THREAD if (PyThread_get_thread_ident() != main_thread) return 0; #endif /* * The is_tripped variable is meant to speed up the calls to * PyErr_CheckSignals (both directly or via pending calls) when no * signal has arrived. This variable is set to 1 when a signal arrives * and it is set to 0 here, when we know some signals arrived. This way * we can run the registered handlers with no signals blocked. * * NOTE: with this approach we can have a situation where is_tripped is * 1 but we have no more signals to handle (Handlers[i].tripped * is 0 for every signal i). This won't do us any harm (except * we're gonna spent some cycles for nothing). This happens when * we receive a signal i after we zero is_tripped and before we * check Handlers[i].tripped. */ _Py_atomic_store(&is_tripped, 0); if (!(f = (PyObject *)PyEval_GetFrame())) f = Py_None; for (i = 1; i < NSIG; i++) { if (_Py_atomic_load_relaxed(&Handlers[i].tripped)) { PyObject *result = NULL; PyObject *arglist = Py_BuildValue("(iO)", i, f); _Py_atomic_store_relaxed(&Handlers[i].tripped, 0); if (arglist) { result = PyEval_CallObject(Handlers[i].func, arglist); Py_DECREF(arglist); } if (!result) { _Py_atomic_store(&is_tripped, 1); return -1; } Py_DECREF(result); } } return 0; } /* Replacements for intrcheck.c functionality * Declared in pyerrors.h */ void PyErr_SetInterrupt(void) { trip_signal(SIGINT); } void PyOS_InitInterrupts(void) { PyObject *m = PyImport_ImportModule("_signal"); if (m) { Py_DECREF(m); } } void PyOS_FiniInterrupts(void) { finisignal(); } int PyOS_InterruptOccurred(void) { if (_Py_atomic_load_relaxed(&Handlers[SIGINT].tripped)) { #ifdef WITH_THREAD if (PyThread_get_thread_ident() != main_thread) return 0; #endif _Py_atomic_store_relaxed(&Handlers[SIGINT].tripped, 0); return 1; } return 0; } static void _clear_pending_signals(void) { int i; if (!_Py_atomic_load(&is_tripped)) return; _Py_atomic_store(&is_tripped, 0); for (i = 1; i < NSIG; ++i) { _Py_atomic_store_relaxed(&Handlers[i].tripped, 0); } } void _PySignal_AfterFork(void) { /* Clear the signal flags after forking so that they aren't handled * in both processes if they came in just before the fork() but before * the interpreter had an opportunity to call the handlers. issue9535. */ _clear_pending_signals(); #ifdef WITH_THREAD main_thread = PyThread_get_thread_ident(); main_pid = getpid(); #endif } int _PyOS_IsMainThread(void) { #ifdef WITH_THREAD return PyThread_get_thread_ident() == main_thread; #else return 1; #endif } #ifdef MS_WINDOWS void *_PyOS_SigintEvent(void) { /* Returns a manual-reset event which gets tripped whenever SIGINT is received. Python.h does not include windows.h so we do cannot use HANDLE as the return type of this function. We use void* instead. */ return sigint_event; } #endif