67 lines
1.9 KiB
C
67 lines
1.9 KiB
C
/*-------------------------------------------------------------------------
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*
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* pqsignal.c--
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* reliable BSD-style signal(2) routine stolen from RWW who stole it
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* from Stevens...
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/libpq/pqsignal.c,v 1.7 1997/09/08 02:23:19 momjian Exp $
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*
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* NOTES
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* This shouldn't be in libpq, but the monitor and some other
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* things need it...
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*
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* A NOTE ABOUT SIGNAL HANDLING ACROSS THE VARIOUS PLATFORMS.
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*
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* config.h defines the macro USE_POSIX_SIGNALS for some platforms and
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* not for others. This file and pqsignal.h use that macro to decide
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* how to handle signalling.
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*
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* signal(2) handling - this is here because it affects some of
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* the frontend commands as well as the backend server.
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*
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* Ultrix and SunOS provide BSD signal(2) semantics by default.
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*
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* SVID2 and POSIX signal(2) semantics differ from BSD signal(2)
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* semantics. We can use the POSIX sigaction(2) on systems that
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* allow us to request restartable signals (SA_RESTART).
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*
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* Some systems don't allow restartable signals at all unless we
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* link to a special BSD library.
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*
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* We devoutly hope that there aren't any systems that provide
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* neither POSIX signals nor BSD signals. The alternative
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* is to do signal-handler reinstallation, which doesn't work well
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* at all.
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* ------------------------------------------------------------------------*/
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#include <postgres.h>
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#include <signal.h>
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#include <libpq/pqsignal.h>
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pqsigfunc
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pqsignal(int signo, pqsigfunc func)
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{
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#if !defined(USE_POSIX_SIGNALS)
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return signal(signo, func);
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#else
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struct sigaction act,
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oact;
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act.sa_handler = func;
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sigemptyset(&act.sa_mask);
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act.sa_flags = 0;
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if (signo != SIGALRM)
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{
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act.sa_flags |= SA_RESTART;
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}
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if (sigaction(signo, &act, &oact) < 0)
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return (SIG_ERR);
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return (oact.sa_handler);
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#endif /* !USE_POSIX_SIGNALS */
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}
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