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Move pqsignal() to libpgport.

We had two copies of this function in the backend and libpq, which was
already pretty bogus, but it turns out that we need it in some other
programs that don't use libpq (such as pg_test_fsync).  So put it where
it probably should have been all along.  The signal-mask-initialization
support in src/backend/libpq/pqsignal.c stays where it is, though, since
we only need that in the backend.
This commit is contained in:
Tom Lane
2013-03-17 12:06:42 -04:00
parent d43837d030
commit da5aeccf64
30 changed files with 99 additions and 184 deletions

76
src/port/pqsignal.c Normal file
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/*-------------------------------------------------------------------------
*
* 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 */