77 lines
2.2 KiB
C
77 lines
2.2 KiB
C
|
/*-------------------------------------------------------------------------
|
||
|
|
*
|
||
|
|
* pqsignal.c
|
||
|
|
* reliable BSD-style signal(2) routine stolen from RWW who stole it
|
||
|
|
* from Stevens...
|
||
|
|
*
|
||
|
|
* Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
|
||
|
|
* Portions Copyright (c) 1994, Regents of the University of California
|
||
|
|
*
|
||
|
|
*
|
||
|
|
* IDENTIFICATION
|
||
|
|
* src/port/pqsignal.c
|
||
|
|
*
|
||
|
|
* A NOTE ABOUT SIGNAL HANDLING ACROSS THE VARIOUS PLATFORMS.
|
||
|
|
*
|
||
|
|
* pg_config.h defines the macro HAVE_POSIX_SIGNALS for some platforms and
|
||
|
|
* not for others. We use that here to decide how to handle signalling.
|
||
|
|
*
|
||
|
|
* Ultrix and SunOS provide BSD signal(2) semantics by default.
|
||
|
|
*
|
||
|
|
* SVID2 and POSIX signal(2) semantics differ from BSD signal(2)
|
||
|
|
* semantics. We can use the POSIX sigaction(2) on systems that
|
||
|
|
* allow us to request restartable signals (SA_RESTART).
|
||
|
|
*
|
||
|
|
* Some systems don't allow restartable signals at all unless we
|
||
|
|
* link to a special BSD library.
|
||
|
|
*
|
||
|
|
* We devoutly hope that there aren't any Unix-oid systems that provide
|
||
|
|
* neither POSIX signals nor BSD signals. The alternative is to do
|
||
|
|
* signal-handler reinstallation, which doesn't work well at all.
|
||
|
|
*
|
||
|
|
* Windows, of course, is resolutely in a class by itself. This file
|
||
|
|
* should not get compiled at all on Windows. We have an emulation of
|
||
|
|
* pqsignal() in src/backend/port/win32/signal.c for the backend
|
||
|
|
* environment; frontend programs are out of luck.
|
||
|
|
* ------------------------------------------------------------------------
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "c.h"
|
||
|
|
|
||
|
|
#include <signal.h>
|
||
|
|
|
||
|
|
#ifndef WIN32
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Set up a signal handler for signal "signo"
|
||
|
|
*
|
||
|
|
* Returns the previous handler. It's expected that the installed handler
|
||
|
|
* will persist across multiple deliveries of the signal (unlike the original
|
||
|
|
* POSIX definition of signal(2)).
|
||
|
|
*/
|
||
|
|
pqsigfunc
|
||
|
|
pqsignal(int signo, pqsigfunc func)
|
||
|
|
{
|
||
|
|
#if !defined(HAVE_POSIX_SIGNALS)
|
||
|
|
return signal(signo, func);
|
||
|
|
#else
|
||
|
|
struct sigaction act,
|
||
|
|
oact;
|
||
|
|
|
||
|
|
act.sa_handler = func;
|
||
|
|
sigemptyset(&act.sa_mask);
|
||
|
|
act.sa_flags = 0;
|
||
|
|
if (signo != SIGALRM)
|
||
|
|
act.sa_flags |= SA_RESTART;
|
||
|
|
#ifdef SA_NOCLDSTOP
|
||
|
|
if (signo == SIGCHLD)
|
||
|
|
act.sa_flags |= SA_NOCLDSTOP;
|
||
|
|
#endif
|
||
|
|
if (sigaction(signo, &act, &oact) < 0)
|
||
|
|
return SIG_ERR;
|
||
|
|
return oact.sa_handler;
|
||
|
|
#endif /* !HAVE_POSIX_SIGNALS */
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* WIN32 */
|