mirror of https://github.com/python/cpython
625 lines
14 KiB
C
625 lines
14 KiB
C
/***********************************************************
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Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
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The Netherlands.
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and its
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documentation for any purpose and without fee is hereby granted,
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provided that the above copyright notice appear in all copies and that
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both that copyright notice and this permission notice appear in
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supporting documentation, and that the names of Stichting Mathematisch
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Centrum or CWI or Corporation for National Research Initiatives or
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CNRI not be used in advertising or publicity pertaining to
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distribution of the software without specific, written prior
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permission.
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While CWI is the initial source for this software, a modified version
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is made available by the Corporation for National Research Initiatives
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(CNRI) at the Internet address ftp://ftp.python.org.
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STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH
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REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH
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CENTRUM OR CNRI BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
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DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
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TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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PERFORMANCE OF THIS SOFTWARE.
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******************************************************************/
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/* Signal module -- many thanks to Lance Ellinghaus */
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/* XXX Signals should be recorded per thread, now we have thread state. */
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#include "Python.h"
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#include "intrcheck.h"
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#ifdef MS_WIN32
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#include <process.h>
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#endif
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <signal.h>
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#ifndef SIG_ERR
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#define SIG_ERR ((RETSIGTYPE (*)())-1)
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#endif
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#ifndef NSIG
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#ifdef _SIGMAX
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#define NSIG (_SIGMAX + 1) /* For QNX */
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#else
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#define NSIG (SIGMAX + 1) /* for djgpp */
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#endif
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#endif
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/*
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NOTES ON THE INTERACTION BETWEEN SIGNALS AND THREADS
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When threads are supported, we want the following semantics:
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- only the main thread can set a signal handler
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- any thread can get a signal handler
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- signals are only delivered to the main thread
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I.e. we don't support "synchronous signals" like SIGFPE (catching
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this doesn't make much sense in Python anyway) nor do we support
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signals as a means of inter-thread communication, since not all
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thread implementations support that (at least our thread library
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doesn't).
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We still have the problem that in some implementations signals
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generated by the keyboard (e.g. SIGINT) are delivered to all
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threads (e.g. SGI), while in others (e.g. Solaris) such signals are
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delivered to one random thread (an intermediate possibility would
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be to deliver it to the main thread -- POSIX?). For now, we have
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a working implementation that works in all three cases -- the
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handler ignores signals if getpid() isn't the same as in the main
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thread. XXX This is a hack.
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*/
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#ifdef WITH_THREAD
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#include <sys/types.h> /* For pid_t */
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#include "thread.h"
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static long main_thread;
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static pid_t main_pid;
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#endif
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static struct {
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int tripped;
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PyObject *func;
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} Handlers[NSIG];
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static int is_tripped = 0; /* Speed up sigcheck() when none tripped */
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static PyObject *DefaultHandler;
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static PyObject *IgnoreHandler;
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static PyObject *IntHandler;
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static RETSIGTYPE (*old_siginthandler)() = SIG_DFL;
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static PyObject *
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signal_default_int_handler(self, arg)
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PyObject *self;
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PyObject *arg;
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{
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PyErr_SetNone(PyExc_KeyboardInterrupt);
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return NULL;
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}
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static RETSIGTYPE
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signal_handler(sig_num)
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int sig_num;
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{
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#ifdef WITH_THREAD
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/* See NOTES section above */
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if (getpid() == main_pid) {
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#endif
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is_tripped++;
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Handlers[sig_num].tripped = 1;
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Py_AddPendingCall(
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(int (*) Py_PROTO((ANY *)))PyErr_CheckSignals, NULL);
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#ifdef WITH_THREAD
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}
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#endif
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#ifdef SIGCHLD
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if (sig_num == SIGCHLD) {
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/* To avoid infinite recursion, this signal remains
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reset until explicit re-instated.
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Don't clear the 'func' field as it is our pointer
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to the Python handler... */
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return;
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}
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#endif
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(void *)signal(sig_num, &signal_handler);
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}
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#ifdef HAVE_ALARM
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static PyObject *
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signal_alarm(self, args)
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PyObject *self; /* Not used */
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PyObject *args;
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{
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int t;
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if (!PyArg_Parse(args, "i", &t))
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return NULL;
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/* alarm() returns the number of seconds remaining */
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return PyInt_FromLong(alarm(t));
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}
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#endif
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#ifdef HAVE_PAUSE
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static PyObject *
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signal_pause(self, args)
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PyObject *self; /* Not used */
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PyObject *args;
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{
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if (!PyArg_NoArgs(args))
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return NULL;
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Py_BEGIN_ALLOW_THREADS
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(void)pause();
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Py_END_ALLOW_THREADS
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/* make sure that any exceptions that got raised are propagated
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* back into Python
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*/
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if (PyErr_CheckSignals())
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return NULL;
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Py_INCREF(Py_None);
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return Py_None;
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}
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#endif
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static PyObject *
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signal_signal(self, args)
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PyObject *self; /* Not used */
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PyObject *args;
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{
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PyObject *obj;
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int sig_num;
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PyObject *old_handler;
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RETSIGTYPE (*func)();
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if (!PyArg_Parse(args, "(iO)", &sig_num, &obj))
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return NULL;
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#ifdef WITH_THREAD
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if (get_thread_ident() != main_thread) {
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PyErr_SetString(PyExc_ValueError,
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"signal only works in main thread");
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return NULL;
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}
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#endif
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if (sig_num < 1 || sig_num >= NSIG) {
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PyErr_SetString(PyExc_ValueError,
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"signal number out of range");
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return NULL;
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}
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if (obj == IgnoreHandler)
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func = SIG_IGN;
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else if (obj == DefaultHandler)
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func = SIG_DFL;
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else if (!PyCallable_Check(obj)) {
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PyErr_SetString(PyExc_TypeError,
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"signal handler must be signal.SIG_IGN, signal.SIG_DFL, or a callable object");
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return NULL;
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}
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else
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func = signal_handler;
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if (signal(sig_num, func) == SIG_ERR) {
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PyErr_SetFromErrno(PyExc_RuntimeError);
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return NULL;
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}
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old_handler = Handlers[sig_num].func;
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Handlers[sig_num].tripped = 0;
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Py_INCREF(obj);
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Handlers[sig_num].func = obj;
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return old_handler;
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}
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static PyObject *
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signal_get_signal(self, args)
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PyObject *self; /* Not used */
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PyObject *args;
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{
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int sig_num;
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PyObject *old_handler;
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if (!PyArg_Parse(args, "i", &sig_num))
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return NULL;
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if (sig_num < 1 || sig_num >= NSIG) {
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PyErr_SetString(PyExc_ValueError,
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"signal number out of range");
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return NULL;
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}
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old_handler = Handlers[sig_num].func;
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Py_INCREF(old_handler);
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return old_handler;
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}
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/* List of functions defined in the module */
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static PyMethodDef signal_methods[] = {
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#ifdef HAVE_ALARM
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{"alarm", signal_alarm},
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#endif
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{"signal", signal_signal},
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{"getsignal", signal_get_signal},
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#ifdef HAVE_PAUSE
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{"pause", signal_pause},
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#endif
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{"default_int_handler", signal_default_int_handler},
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{NULL, NULL} /* sentinel */
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};
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void
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initsignal()
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{
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PyObject *m, *d, *x;
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int i;
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#ifdef WITH_THREAD
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main_thread = get_thread_ident();
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main_pid = getpid();
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#endif
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/* Create the module and add the functions */
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m = Py_InitModule("signal", signal_methods);
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/* Add some symbolic constants to the module */
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d = PyModule_GetDict(m);
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x = DefaultHandler = PyInt_FromLong((long)SIG_DFL);
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if (!x || PyDict_SetItemString(d, "SIG_DFL", x) < 0)
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goto finally;
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x = IgnoreHandler = PyInt_FromLong((long)SIG_IGN);
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if (!x || PyDict_SetItemString(d, "SIG_IGN", x) < 0)
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goto finally;
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x = PyInt_FromLong((long)NSIG);
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if (!x || PyDict_SetItemString(d, "NSIG", x) < 0)
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goto finally;
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Py_DECREF(x);
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x = IntHandler = PyDict_GetItemString(d, "default_int_handler");
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if (!x)
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goto finally;
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Py_INCREF(IntHandler);
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Handlers[0].tripped = 0;
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for (i = 1; i < NSIG; i++) {
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RETSIGTYPE (*t)();
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#ifdef HAVE_SIGACTION
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struct sigaction act;
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sigaction(i, 0, &act);
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t = act.sa_handler;
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#else
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t = signal(i, SIG_IGN);
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signal(i, t);
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#endif
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Handlers[i].tripped = 0;
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if (t == SIG_DFL)
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Handlers[i].func = DefaultHandler;
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else if (t == SIG_IGN)
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Handlers[i].func = IgnoreHandler;
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else
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Handlers[i].func = Py_None; /* None of our business */
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Py_INCREF(Handlers[i].func);
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}
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if (Handlers[SIGINT].func == DefaultHandler) {
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/* Install default int handler */
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Py_INCREF(IntHandler);
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Py_DECREF(Handlers[SIGINT].func);
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Handlers[SIGINT].func = IntHandler;
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old_siginthandler = signal(SIGINT, &signal_handler);
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}
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#ifdef SIGHUP
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x = PyInt_FromLong(SIGHUP);
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PyDict_SetItemString(d, "SIGHUP", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGINT
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x = PyInt_FromLong(SIGINT);
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PyDict_SetItemString(d, "SIGINT", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGQUIT
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x = PyInt_FromLong(SIGQUIT);
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PyDict_SetItemString(d, "SIGQUIT", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGILL
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x = PyInt_FromLong(SIGILL);
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PyDict_SetItemString(d, "SIGILL", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGTRAP
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x = PyInt_FromLong(SIGTRAP);
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PyDict_SetItemString(d, "SIGTRAP", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGIOT
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x = PyInt_FromLong(SIGIOT);
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PyDict_SetItemString(d, "SIGIOT", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGABRT
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x = PyInt_FromLong(SIGABRT);
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PyDict_SetItemString(d, "SIGABRT", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGEMT
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x = PyInt_FromLong(SIGEMT);
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PyDict_SetItemString(d, "SIGEMT", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGFPE
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x = PyInt_FromLong(SIGFPE);
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PyDict_SetItemString(d, "SIGFPE", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGKILL
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x = PyInt_FromLong(SIGKILL);
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PyDict_SetItemString(d, "SIGKILL", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGBUS
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x = PyInt_FromLong(SIGBUS);
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PyDict_SetItemString(d, "SIGBUS", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGSEGV
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x = PyInt_FromLong(SIGSEGV);
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PyDict_SetItemString(d, "SIGSEGV", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGSYS
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x = PyInt_FromLong(SIGSYS);
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PyDict_SetItemString(d, "SIGSYS", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGPIPE
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x = PyInt_FromLong(SIGPIPE);
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PyDict_SetItemString(d, "SIGPIPE", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGALRM
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x = PyInt_FromLong(SIGALRM);
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PyDict_SetItemString(d, "SIGALRM", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGTERM
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x = PyInt_FromLong(SIGTERM);
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PyDict_SetItemString(d, "SIGTERM", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGUSR1
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x = PyInt_FromLong(SIGUSR1);
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PyDict_SetItemString(d, "SIGUSR1", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGUSR2
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x = PyInt_FromLong(SIGUSR2);
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PyDict_SetItemString(d, "SIGUSR2", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGCLD
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x = PyInt_FromLong(SIGCLD);
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PyDict_SetItemString(d, "SIGCLD", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGCHLD
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x = PyInt_FromLong(SIGCHLD);
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PyDict_SetItemString(d, "SIGCHLD", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGPWR
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x = PyInt_FromLong(SIGPWR);
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PyDict_SetItemString(d, "SIGPWR", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGIO
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x = PyInt_FromLong(SIGIO);
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PyDict_SetItemString(d, "SIGIO", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGURG
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x = PyInt_FromLong(SIGURG);
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PyDict_SetItemString(d, "SIGURG", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGWINCH
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x = PyInt_FromLong(SIGWINCH);
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PyDict_SetItemString(d, "SIGWINCH", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGPOLL
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x = PyInt_FromLong(SIGPOLL);
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PyDict_SetItemString(d, "SIGPOLL", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGSTOP
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x = PyInt_FromLong(SIGSTOP);
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PyDict_SetItemString(d, "SIGSTOP", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGTSTP
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x = PyInt_FromLong(SIGTSTP);
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PyDict_SetItemString(d, "SIGTSTP", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGCONT
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x = PyInt_FromLong(SIGCONT);
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PyDict_SetItemString(d, "SIGCONT", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGTTIN
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x = PyInt_FromLong(SIGTTIN);
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PyDict_SetItemString(d, "SIGTTIN", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGTTOU
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x = PyInt_FromLong(SIGTTOU);
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PyDict_SetItemString(d, "SIGTTOU", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGVTALRM
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x = PyInt_FromLong(SIGVTALRM);
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PyDict_SetItemString(d, "SIGVTALRM", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGPROF
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x = PyInt_FromLong(SIGPROF);
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PyDict_SetItemString(d, "SIGPROF", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGXCPU
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x = PyInt_FromLong(SIGXCPU);
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PyDict_SetItemString(d, "SIGXCPU", x);
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Py_XDECREF(x);
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#endif
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#ifdef SIGXFSZ
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x = PyInt_FromLong(SIGXFSZ);
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PyDict_SetItemString(d, "SIGXFSZ", x);
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Py_XDECREF(x);
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#endif
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if (!PyErr_Occurred())
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return;
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/* Check for errors */
|
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finally:
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return;
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}
|
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|
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static void
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finisignal()
|
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{
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int i;
|
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PyObject *func;
|
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|
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signal(SIGINT, old_siginthandler);
|
||
old_siginthandler = SIG_DFL;
|
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|
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for (i = 1; i < NSIG; i++) {
|
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func = Handlers[i].func;
|
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Handlers[i].tripped = 0;
|
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Handlers[i].func = NULL;
|
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if (i != SIGINT && func != NULL && func != Py_None &&
|
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func != DefaultHandler && func != IgnoreHandler)
|
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signal(i, SIG_DFL);
|
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Py_XDECREF(func);
|
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}
|
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|
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Py_XDECREF(IntHandler);
|
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IntHandler = NULL;
|
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Py_XDECREF(DefaultHandler);
|
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DefaultHandler = NULL;
|
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Py_XDECREF(IgnoreHandler);
|
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IgnoreHandler = NULL;
|
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}
|
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|
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|
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|
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/* Declared in pyerrors.h */
|
||
int
|
||
PyErr_CheckSignals()
|
||
{
|
||
int i;
|
||
PyObject *f;
|
||
|
||
if (!is_tripped)
|
||
return 0;
|
||
#ifdef WITH_THREAD
|
||
if (get_thread_ident() != main_thread)
|
||
return 0;
|
||
#endif
|
||
if (!(f = PyEval_GetFrame()))
|
||
f = Py_None;
|
||
|
||
for (i = 1; i < NSIG; i++) {
|
||
if (Handlers[i].tripped) {
|
||
PyObject *result = NULL;
|
||
PyObject *arglist = Py_BuildValue("(iO)", i, f);
|
||
Handlers[i].tripped = 0;
|
||
|
||
if (arglist) {
|
||
result = PyEval_CallObject(Handlers[i].func,
|
||
arglist);
|
||
Py_DECREF(arglist);
|
||
}
|
||
if (!result)
|
||
return -1;
|
||
|
||
Py_DECREF(result);
|
||
}
|
||
}
|
||
is_tripped = 0;
|
||
return 0;
|
||
}
|
||
|
||
|
||
/* Replacements for intrcheck.c functionality
|
||
* Declared in pyerrors.h
|
||
*/
|
||
void
|
||
PyErr_SetInterrupt()
|
||
{
|
||
is_tripped++;
|
||
Handlers[SIGINT].tripped = 1;
|
||
Py_AddPendingCall((int (*) Py_PROTO((ANY *)))PyErr_CheckSignals, NULL);
|
||
}
|
||
|
||
void
|
||
PyOS_InitInterrupts()
|
||
{
|
||
initsignal();
|
||
_PyImport_FixupExtension("signal", "signal");
|
||
}
|
||
|
||
void
|
||
PyOS_FiniInterrupts()
|
||
{
|
||
finisignal();
|
||
}
|
||
|
||
int
|
||
PyOS_InterruptOccurred()
|
||
{
|
||
if (Handlers[SIGINT].tripped) {
|
||
#ifdef WITH_THREAD
|
||
if (get_thread_ident() != main_thread)
|
||
return 0;
|
||
#endif
|
||
Handlers[SIGINT].tripped = 0;
|
||
return 1;
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
void
|
||
PyOS_AfterFork()
|
||
{
|
||
#ifdef WITH_THREAD
|
||
main_thread = get_thread_ident();
|
||
main_pid = getpid();
|
||
#endif
|
||
}
|