mirror of https://github.com/python/cpython.git
444 lines
10 KiB
C
444 lines
10 KiB
C
/***********************************************************
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Copyright 1991, 1992, 1993, 1994 by Stichting Mathematisch Centrum,
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Amsterdam, 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 not be used in advertising or publicity pertaining to
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distribution of the software without specific, written prior permission.
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STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
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THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE
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FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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******************************************************************/
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/* Signal module -- many thanks to Lance Ellinghouse */
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#include "allobjects.h"
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#include "modsupport.h"
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#include "ceval.h"
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#include "intrcheck.h"
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#include <signal.h>
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#include <errno.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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/*
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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 "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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struct signalhandler_list {
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int tripped;
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object *func;
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};
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static struct signalhandler_list sig_list[NSIG];
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static int tripped = 0; /* Speed up sigcheck() when none tripped */
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static object *sig_dfl_object;
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static object *sig_ign_object;
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static object *default_int_handler_object;
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static object *
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default_int_handler(self, arg)
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object *self;
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object *arg;
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{
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err_set(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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tripped++;
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sig_list[sig_num].tripped = 1;
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#ifdef WITH_THREAD
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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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static object *
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signal_alarm(self, args)
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object *self; /* Not used */
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object *args;
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{
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int t;
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if (!getargs(args, "i", &t))
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return NULL;
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alarm(t);
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INCREF(None);
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return None;
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}
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static object *
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signal_signal(self, args)
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object *self; /* Not used */
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object *args;
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{
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object *obj;
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int sig_num;
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object *old_handler;
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RETSIGTYPE (*func)();
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if (!getargs(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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err_setstr(ValueError, "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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err_setstr(ValueError, "signal number out of range");
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return NULL;
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}
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if (obj == sig_ign_object)
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func = SIG_IGN;
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else if (obj == sig_dfl_object)
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func = SIG_DFL;
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else if (!is_methodobject(obj) &&
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!is_funcobject(obj) &&
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!is_instancemethodobject(obj)) {
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err_setstr(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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err_errno(RuntimeError);
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return NULL;
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}
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old_handler = sig_list[sig_num].func;
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sig_list[sig_num].tripped = 0;
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INCREF(obj);
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sig_list[sig_num].func = obj;
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return old_handler;
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}
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static object *
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signal_getsignal(self, args)
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object *self; /* Not used */
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object *args;
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{
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int sig_num;
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object *old_handler;
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if (!getargs(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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err_setstr(ValueError, "signal number out of range");
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return NULL;
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}
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old_handler = sig_list[sig_num].func;
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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 struct methodlist signal_methods[] = {
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{"alarm", signal_alarm},
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{"signal", signal_signal},
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{"getsignal", signal_getsignal},
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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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object *m, *d, *x;
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object *b_dict;
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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 = initmodule("signal", signal_methods);
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/* Add some symbolic constants to the module */
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d = getmoduledict(m);
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sig_dfl_object = newintobject((long)SIG_DFL);
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dictinsert(d, "SIG_DFL", sig_dfl_object);
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sig_ign_object = newintobject((long)SIG_IGN);
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dictinsert(d, "SIG_IGN", sig_ign_object);
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dictinsert(d, "NSIG", newintobject((long)NSIG));
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default_int_handler_object = newmethodobject("default_int_handler",
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default_int_handler,
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(object *)NULL,
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0);
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dictinsert(d, "default_int_handler", default_int_handler_object);
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sig_list[0].tripped = 0;
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for (i = 1; i < NSIG; i++) {
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RETSIGTYPE (*t)();
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t = signal(i, SIG_IGN);
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signal(i, t);
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sig_list[i].tripped = 0;
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if (t == SIG_DFL)
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sig_list[i].func = sig_dfl_object;
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else if (t == SIG_IGN)
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sig_list[i].func = sig_ign_object;
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else
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sig_list[i].func = None; /* None of our business */
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INCREF(sig_list[i].func);
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}
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if (sig_list[SIGINT].func == sig_dfl_object) {
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/* Install default int handler */
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DECREF(sig_list[SIGINT].func);
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sig_list[SIGINT].func = default_int_handler_object;
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INCREF(default_int_handler_object);
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signal(SIGINT, &signal_handler);
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}
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#ifdef SIGHUP
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x = newintobject(SIGHUP);
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dictinsert(d, "SIGHUP", x);
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#endif
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#ifdef SIGINT
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x = newintobject(SIGINT);
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dictinsert(d, "SIGINT", x);
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#endif
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#ifdef SIGQUIT
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x = newintobject(SIGQUIT);
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dictinsert(d, "SIGQUIT", x);
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#endif
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#ifdef SIGILL
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x = newintobject(SIGILL);
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dictinsert(d, "SIGILL", x);
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#endif
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#ifdef SIGTRAP
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x = newintobject(SIGTRAP);
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dictinsert(d, "SIGTRAP", x);
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#endif
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#ifdef SIGIOT
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x = newintobject(SIGIOT);
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dictinsert(d, "SIGIOT", x);
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#endif
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#ifdef SIGABRT
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x = newintobject(SIGABRT);
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dictinsert(d, "SIGABRT", x);
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#endif
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#ifdef SIGEMT
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x = newintobject(SIGEMT);
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dictinsert(d, "SIGEMT", x);
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#endif
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#ifdef SIGFPE
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x = newintobject(SIGFPE);
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dictinsert(d, "SIGFPE", x);
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#endif
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#ifdef SIGKILL
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x = newintobject(SIGKILL);
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dictinsert(d, "SIGKILL", x);
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#endif
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#ifdef SIGBUS
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x = newintobject(SIGBUS);
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dictinsert(d, "SIGBUS", x);
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#endif
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#ifdef SIGSEGV
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x = newintobject(SIGSEGV);
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dictinsert(d, "SIGSEGV", x);
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#endif
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#ifdef SIGSYS
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x = newintobject(SIGSYS);
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dictinsert(d, "SIGSYS", x);
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#endif
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#ifdef SIGPIPE
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x = newintobject(SIGPIPE);
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dictinsert(d, "SIGPIPE", x);
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#endif
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#ifdef SIGALRM
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x = newintobject(SIGALRM);
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dictinsert(d, "SIGALRM", x);
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#endif
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#ifdef SIGTERM
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x = newintobject(SIGTERM);
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dictinsert(d, "SIGTERM", x);
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#endif
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#ifdef SIGUSR1
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x = newintobject(SIGUSR1);
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dictinsert(d, "SIGUSR1", x);
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#endif
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#ifdef SIGUSR2
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x = newintobject(SIGUSR2);
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dictinsert(d, "SIGUSR2", x);
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#endif
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#ifdef SIGCLD
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x = newintobject(SIGCLD);
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dictinsert(d, "SIGCLD", x);
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#endif
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#ifdef SIGCHLD
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x = newintobject(SIGCHLD);
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dictinsert(d, "SIGCHLD", x);
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#endif
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#ifdef SIGPWR
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x = newintobject(SIGPWR);
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dictinsert(d, "SIGPWR", x);
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#endif
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#ifdef SIGIO
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x = newintobject(SIGIO);
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dictinsert(d, "SIGIO", x);
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#endif
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#ifdef SIGURG
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x = newintobject(SIGURG);
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dictinsert(d, "SIGURG", x);
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#endif
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#ifdef SIGWINCH
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x = newintobject(SIGWINCH);
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dictinsert(d, "SIGWINCH", x);
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#endif
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#ifdef SIGPOLL
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x = newintobject(SIGPOLL);
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dictinsert(d, "SIGPOLL", x);
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#endif
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#ifdef SIGSTOP
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x = newintobject(SIGSTOP);
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dictinsert(d, "SIGSTOP", x);
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#endif
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#ifdef SIGTSTP
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x = newintobject(SIGTSTP);
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dictinsert(d, "SIGTSTP", x);
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#endif
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#ifdef SIGCONT
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x = newintobject(SIGCONT);
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dictinsert(d, "SIGCONT", x);
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#endif
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#ifdef SIGTTIN
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x = newintobject(SIGTTIN);
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dictinsert(d, "SIGTTIN", x);
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#endif
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#ifdef SIGTTOU
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x = newintobject(SIGTTOU);
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dictinsert(d, "SIGTTOU", x);
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#endif
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#ifdef SIGVTALRM
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x = newintobject(SIGVTALRM);
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dictinsert(d, "SIGVTALRM", x);
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#endif
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#ifdef SIGPROF
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x = newintobject(SIGPROF);
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dictinsert(d, "SIGPROF", x);
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#endif
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#ifdef SIGCPU
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x = newintobject(SIGCPU);
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dictinsert(d, "SIGCPU", x);
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#endif
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#ifdef SIGFSZ
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x = newintobject(SIGFSZ);
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dictinsert(d, "SIGFSZ", x);
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#endif
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/* Check for errors */
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if (err_occurred())
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fatal("can't initialize module signal");
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}
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int
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sigcheck()
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{
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int i;
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object *f;
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if (!tripped)
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return 0;
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#ifdef WITH_THREAD
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if (get_thread_ident() != main_thread)
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return 0;
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#endif
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f = getframe();
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if (f == NULL)
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f = None;
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for (i = 1; i < NSIG; i++) {
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if (sig_list[i].tripped) {
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object *arglist, *result;
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sig_list[i].tripped = 0;
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arglist = mkvalue("(iO)", i, f);
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if (arglist == NULL)
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result = NULL;
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else {
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result = call_object(sig_list[i].func,arglist);
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DECREF(arglist);
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}
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if (result == NULL) {
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return 1;
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} else {
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DECREF(result);
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}
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}
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}
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tripped = 0;
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return 0;
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}
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/* Replacement for intrcheck.c functionality */
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void
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initintr()
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{
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initsignal();
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}
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int
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intrcheck()
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{
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if (sig_list[SIGINT].tripped) {
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#ifdef WITH_THREAD
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if (get_thread_ident() != main_thread)
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return 0;
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#endif
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sig_list[SIGINT].tripped = 0;
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return 1;
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}
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return 0;
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}
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