diff options
| -rw-r--r-- | Doc/lib/libsignal.tex | 54 | ||||
| -rw-r--r-- | Doc/whatsnew/whatsnew23.tex | 6 | ||||
| -rw-r--r-- | Lib/test/test_signal.py | 61 | ||||
| -rw-r--r-- | Misc/NEWS | 3 | ||||
| -rw-r--r-- | Modules/signalmodule.c | 171 |
5 files changed, 6 insertions, 289 deletions
diff --git a/Doc/lib/libsignal.tex b/Doc/lib/libsignal.tex index 3029385..e3aa171 100644 --- a/Doc/lib/libsignal.tex +++ b/Doc/lib/libsignal.tex @@ -18,6 +18,10 @@ the handler for \constant{SIGCHLD}, which follows the underlying implementation. \item +There is no way to ``block'' signals temporarily from critical +sections (since this is not supported by all \UNIX{} flavors). + +\item Although Python signal handlers are called asynchronously as far as the Python user is concerned, they can only occur between the ``atomic'' instructions of the Python interpreter. This means that @@ -88,16 +92,6 @@ The variables defined in the \module{signal} module are: One more than the number of the highest signal number. \end{datadesc} -\begin{datadesc}{SIG_BLOCK} -\end{datadesc} -\begin{datadesc}{SIG_UNBLOCK} -\end{datadesc} -\begin{datadesc}{SIG_SETMASK} - These constants are for use as the first parameter of the - \function{sigprocmask} function described below. -\end{datadesc} - - The \module{signal} module defines the following functions: \begin{funcdesc}{alarm}{time} @@ -150,46 +144,6 @@ The \module{signal} module defines the following functions: \obindex{frame} \end{funcdesc} -The following functions are supported if your platform does. Most -modern \UNIX-alikes now do. - -\begin{funcdesc}{sigpending}{} - Return the set of pending signals, i.e. a list containing the - numbers of those signals that have been raised while blocked. - \versionadded{2.3} -\end{funcdesc} - -\begin{funcdesc}{sigprocmask}{how, sigset} - Change the list of currently blocked signals. The parameter - \var{how} should be one of \constant{SIG_BLOCK}, - \constant{SIG_UNBLOCK} or \constant{SIG_SETMASK} and \var{sigset} - should be a sequence of signal numbers. The behaviour of the call - depends on the value of \var{how}: - - \begin{tableii}{l|l}{textrm}{Value of \var{how}}{Behaviour of call} - \lineii{\constant{SIG_BLOCK}} - {The set of blocked signals is the union of the current set - and \var{sigset}.} - \lineii{\constant{SIG_UNBLOCK}} - {The signals in \var{sigset} are removed from the current - set of blocked signals. It is legal to attempt to unblock - a signal which is not blocked.} - \lineii{\constant{SIG_SETMASK}} - {The set of blocked signals is set to the \var{sigset}.} - \end{tableii} - - A list contating the numbers of the previously blocked signals is - returned. - \versionadded{2.3} -\end{funcdesc} - -\begin{funcdesc}{sigsuspend}{sigset} - Temporarily replace the signal mask with \var{sigset} (which should - be a sequnce of signal numbers) and suspend the process until a - signal is received. - \versionadded{2.3} -\end{funcdesc} - \subsection{Example} \nodename{Signal Example} diff --git a/Doc/whatsnew/whatsnew23.tex b/Doc/whatsnew/whatsnew23.tex index 362db5f..de46869 100644 --- a/Doc/whatsnew/whatsnew23.tex +++ b/Doc/whatsnew/whatsnew23.tex @@ -1485,10 +1485,8 @@ it immediately.) location. \item Support for more advanced POSIX signal handling was added -to the \module{signal} module by adding the \function{sigpending}, -\function{sigprocmask} and \function{sigsuspend} functions where supported -by the platform. These functions make it possible to avoid some previously -unavoidable race conditions with signal handling. +to the \module{signal} but then removed again as it proved impossible +to make it work reliably across platforms. \item The \module{socket} module now supports timeouts. You can call the \method{settimeout(\var{t})} method on a socket object to diff --git a/Lib/test/test_signal.py b/Lib/test/test_signal.py index 737f160..c984361 100644 --- a/Lib/test/test_signal.py +++ b/Lib/test/test_signal.py @@ -64,64 +64,3 @@ except KeyboardInterrupt: if verbose: print "KeyboardInterrupt (assume the alarm() went off)" - -if hasattr(signal, "sigprocmask"): - class HupDelivered(Exception): - pass - def hup(signum, frame): - raise HupDelivered - def hup2(signum, frame): - signal.signal(signal.SIGHUP, hup) - return - signal.signal(signal.SIGHUP, hup) - - if verbose: - print "blocking SIGHUP" - - defaultmask = signal.sigprocmask(signal.SIG_BLOCK, [signal.SIGHUP]) - - if verbose: - print "sending SIGHUP" - - try: - os.kill(pid, signal.SIGHUP) - except HupDelivered: - raise TestFailed, "HUP not blocked" - - if signal.SIGHUP not in signal.sigpending(): - raise TestFailed, "HUP not pending" - - if verbose: - print "unblocking SIGHUP" - - try: - signal.sigprocmask(signal.SIG_UNBLOCK, [signal.SIGHUP]) - except HupDelivered: - pass - else: - raise TestFailed, "HUP not delivered" - - if verbose: - print "testing sigsuspend" - - signal.sigprocmask(signal.SIG_BLOCK, [signal.SIGHUP]) - signal.signal(signal.SIGHUP, hup2) - - if not os.fork(): - time.sleep(2) - os.kill(pid, signal.SIGHUP) - time.sleep(2) - os.kill(pid, signal.SIGHUP) - os._exit(0) - else: - try: - signal.sigsuspend(defaultmask) - except: - raise TestFailed, "sigsuspend erroneously raised" - - try: - signal.sigsuspend(defaultmask) - except HupDelivered: - pass - else: - raise TestFailed, "sigsupsend didn't raise" @@ -982,9 +982,6 @@ Extension modules of sizeof(int)!=sizeof(long)!=sizeof(void*) is delayed until dl.open is called. -- signal.sigpending, signal.sigprocmask and signal.sigsuspend have - been added where available. - - The sys module acquired a new attribute, api_version, which evaluates to the value of the PYTHON_API_VERSION macro with which the interpreter was compiled. diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c index 2224ec9..e278dd1 100644 --- a/Modules/signalmodule.c +++ b/Modules/signalmodule.c @@ -269,153 +269,6 @@ SIG_DFL -- if the default action for the signal is in effect\n\ None -- if an unknown handler is in effect\n\ anything else -- the callable Python object used as a handler"); -#ifdef HAVE_SIGPROCMASK /* we assume that having SIGPROCMASK is enough - to guarantee full POSIX signal handling */ -/* returns 0 for success, <0 for failure (with exception set) */ -static int -_signal_list_to_sigset(PyObject* seq, sigset_t* set, char* mesg) -{ - int i, len, val; - - seq = PySequence_Fast(seq, mesg); - if (!seq) - return -1; - - len = PySequence_Fast_GET_SIZE(seq); - - sigemptyset(set); - - for (i = 0; i < len; i++) { - val = PyInt_AsLong(PySequence_Fast_GET_ITEM(seq, i)); - if (val == -1 && PyErr_Occurred()) { - Py_DECREF(seq); - return -1; - } - if (sigaddset(set, val) < 0) { - Py_DECREF(seq); - PyErr_SetFromErrno(PyExc_ValueError); - return -1; - } - } - - Py_DECREF(seq); - return 0; -} - -static PyObject* -_signal_sigset_to_list(sigset_t* set) -{ - PyObject* ret; - PyObject* ob; - int i; - - ret = PyList_New(0); - if (!ret) - return NULL; - - for (i = 1; i < NSIG; i++) { - if (sigismember(set, i)) { - ob = PyInt_FromLong(i); - if (!ob) { - Py_DECREF(ret); - return NULL; - } - PyList_Append(ret, ob); - Py_DECREF(ob); - } - } - - return ret; -} - -static PyObject* -signal_sigprocmask(PyObject* self, PyObject* args) -{ - int how; - sigset_t newset, oldset; - PyObject* seq; - - if (!PyArg_ParseTuple(args, "iO", &how, &seq)) - return NULL; - - if (_signal_list_to_sigset(seq, &newset, - "sigprocmask requires a sequence") < 0) - return NULL; - - if (sigprocmask(how, &newset, &oldset) < 0) { - return PyErr_SetFromErrno(PyExc_ValueError); - } - - if (PyErr_CheckSignals()) - return NULL; - - return _signal_sigset_to_list(&oldset); -} - -PyDoc_STRVAR(sigprocmask_doc, -"sigprocmask(how, sigset) -> sigset\n\ -\n\ -Change the list of currently blocked signals. The parameter how should be\n\ -one of SIG_BLOCK, SIG_UNBLOCK or SIG_SETMASK and sigset should be a\n\ -sequence of signal numbers. The behaviour of the call depends on the value\n\ -of how:\n\ -\n\ - SIG_BLOCK\n\ - The set of blocked signals is the union of the current set and the\n\ - sigset argument.\n\ - SIG_UNBLOCK\n\ - The signals in sigset are removed from the current set of blocked\n\ - signals. It is legal to attempt to unblock a signal which is not\n\ - blocked.\n\ - SIG_SETMASK\n\ - The set of blocked signals is set to the argument set.\n\ -\n\ -A list contating the numbers of the previously blocked signals is returned."); - -static PyObject* -signal_sigpending(PyObject* self) -{ - sigset_t set; - - if (sigpending(&set) < 0) { - return PyErr_SetFromErrno(PyExc_ValueError); - } - - return _signal_sigset_to_list(&set); -} - -PyDoc_STRVAR(sigpending_doc, -"sigpending() -> sigset\n\ -\n\ -Return the set of pending signals, i.e. a list containing the numbers of\n\ -those signals that have been raised while blocked."); - -static PyObject* -signal_sigsuspend(PyObject* self, PyObject* arg) -{ - sigset_t set; - - if (_signal_list_to_sigset(arg, &set, - "sigsuspend requires a sequence") < 0) - return NULL; - - Py_BEGIN_ALLOW_THREADS - sigsuspend(&set); - Py_END_ALLOW_THREADS - - if (PyErr_CheckSignals()) - return NULL; - - Py_INCREF(Py_None); - return Py_None; -} - -PyDoc_STRVAR(sigsuspend_doc, -"sigsuspend(sigset) -> None\n\ -\n\ -Temporarily replace the signal mask with sigset (which should be a sequence\n\ -of signal numbers) and suspend the process until a signal is received."); -#endif /* List of functions defined in the module */ static PyMethodDef signal_methods[] = { @@ -430,14 +283,6 @@ static PyMethodDef signal_methods[] = { #endif {"default_int_handler", signal_default_int_handler, METH_VARARGS, default_int_handler_doc}, -#ifdef HAVE_SIGPROCMASK - {"sigprocmask", (PyCFunction)signal_sigprocmask, - METH_VARARGS, sigprocmask_doc}, - {"sigpending", (PyCFunction)signal_sigpending, - METH_NOARGS, sigpending_doc}, - {"sigsuspend", (PyCFunction)signal_sigsuspend, - METH_O, sigsuspend_doc}, -#endif {NULL, NULL} /* sentinel */ }; @@ -453,10 +298,6 @@ 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\ -sigpending() |\n\ -sigprocmask() |-- posix signal mask handling [Unix only]\n\ -sigsuspend() |\n\ -\n\ Constants:\n\ \n\ SIG_DFL -- used to refer to the system default handler\n\ @@ -705,18 +546,6 @@ initsignal(void) PyDict_SetItemString(d, "SIGINFO", x); Py_XDECREF(x); #endif -#ifdef HAVE_SIGPROCMASK - x = PyInt_FromLong(SIG_BLOCK); - PyDict_SetItemString(d, "SIG_BLOCK", x); - Py_XDECREF(x); - x = PyInt_FromLong(SIG_UNBLOCK); - PyDict_SetItemString(d, "SIG_UNBLOCK", x); - Py_XDECREF(x); - x = PyInt_FromLong(SIG_SETMASK); - PyDict_SetItemString(d, "SIG_SETMASK", x); - Py_XDECREF(x); -#endif - if (!PyErr_Occurred()) return; |