Take out my (long since disabled) POSIX signal mask handling code.
I'm not going to have the time or energy to get this working x-platform
-- anyone who does is welcome to the code!
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 @@
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 @@
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 @@
\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 @@
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 @@
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"
diff --git a/Misc/NEWS b/Misc/NEWS
index 5527a1b..877fb9e 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -982,9 +982,6 @@
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 @@
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 @@
#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 @@
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 @@
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;