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359bcaa539
signal handlers in a fork()ed child process when Python is compiled with thread support. The bug was reported by Scott <scott@chronis.icgroup.com>. What happens is that after a fork(), the variables used by the signal module to determine whether this is the main thread or not are bogus, and it decides that no thread is the main thread, so no signals will be delivered. The solution is the addition of PyOS_AfterFork(), which fixes the signal module's variables. A dummy version of the function is present in the intrcheck.c source file which is linked when the signal module is not used.
226 lines
4.5 KiB
C
226 lines
4.5 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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/* Check for interrupts */
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#include "config.h"
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#include "myproto.h"
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#include "mymalloc.h" /* For ANY */
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#include "intrcheck.h"
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/* Copied here from ceval.h -- can't include that file. */
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int Py_AddPendingCall Py_PROTO((int (*func) Py_PROTO((ANY *)), ANY *arg));
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#ifdef QUICKWIN
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#include <io.h>
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void
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PyOS_InitInterrupts()
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{
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}
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void
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PyOS_FiniInterrupts()
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{
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}
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int
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PyOS_InterruptOccurred()
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{
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_wyield();
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}
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#define OK
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#endif /* QUICKWIN */
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#ifdef _M_IX86
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#include <io.h>
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#endif
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#if defined(MSDOS) && !defined(QUICKWIN)
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#ifdef __GNUC__
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/* This is for DJGPP's GO32 extender. I don't know how to trap
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* control-C (There's no API for ctrl-C, and I don't want to mess with
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* the interrupt vectors.) However, this DOES catch control-break.
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* --Amrit
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*/
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#include <go32.h>
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void
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PyOS_InitInterrupts()
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{
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_go32_want_ctrl_break(1 /* TRUE */);
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}
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void
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PyOS_FiniInterrupts()
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{
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}
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int
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PyOS_InterruptOccurred()
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{
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return _go32_was_ctrl_break_hit();
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}
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#else /* !__GNUC__ */
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/* This might work for MS-DOS (untested though): */
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void
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PyOS_InitInterrupts()
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{
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}
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void
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PyOS_FiniInterrupts()
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{
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}
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int
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PyOS_InterruptOccurred()
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{
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int interrupted = 0;
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while (kbhit()) {
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if (getch() == '\003')
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interrupted = 1;
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}
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return interrupted;
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}
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#endif /* __GNUC__ */
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#define OK
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#endif /* MSDOS && !QUICKWIN */
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#ifdef macintosh
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/* The Mac interrupt code has moved to macglue.c */
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#define OK
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#endif /* macintosh */
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#ifndef OK
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/* Default version -- for real operating systems and for Standard C */
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#include <stdio.h>
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#include <string.h>
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#include <signal.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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static int interrupted;
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void
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PyErr_SetInterrupt()
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{
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interrupted = 1;
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}
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extern int PyErr_CheckSignals();
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/* ARGSUSED */
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static RETSIGTYPE
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#ifdef _M_IX86
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intcatcher(int sig) /* So the C compiler shuts up */
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#else /* _M_IX86 */
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intcatcher(sig)
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int sig; /* Not used by required by interface */
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#endif /* _M_IX86 */
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{
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extern void Py_Exit Py_PROTO((int));
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static char message[] =
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"python: to interrupt a truly hanging Python program, interrupt once more.\n";
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switch (interrupted++) {
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case 0:
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break;
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case 1:
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write(2, message, strlen(message));
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break;
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case 2:
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interrupted = 0;
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Py_Exit(1);
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break;
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}
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signal(SIGINT, intcatcher);
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Py_AddPendingCall(PyErr_CheckSignals, NULL);
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}
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static RETSIGTYPE (*old_siginthandler)() = SIG_DFL;
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void
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PyOS_InitInterrupts()
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{
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if ((old_siginthandler = signal(SIGINT, SIG_IGN)) != SIG_IGN)
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signal(SIGINT, intcatcher);
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#ifdef HAVE_SIGINTERRUPT
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/* This is for SunOS and other modern BSD derivatives.
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It means that system calls (like read()) are not restarted
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after an interrupt. This is necessary so interrupting a
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read() or readline() call works as expected.
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XXX On old BSD (pure 4.2 or older) you may have to do this
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differently! */
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siginterrupt(SIGINT, 1);
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#endif /* HAVE_SIGINTERRUPT */
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}
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void
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PyOS_FiniInterrupts()
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{
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signal(SIGINT, old_siginthandler);
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}
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int
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PyOS_InterruptOccurred()
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{
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if (!interrupted)
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return 0;
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interrupted = 0;
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return 1;
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}
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#endif /* !OK */
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void
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PyOS_AfterFork()
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{
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}
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