1996-07-09 08:22:35 +02:00
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/*-------------------------------------------------------------------------
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*
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1999-02-14 00:22:53 +01:00
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* pqsignal.c
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1997-09-07 07:04:48 +02:00
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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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1996-07-09 08:22:35 +02:00
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*
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2003-08-04 04:40:20 +02:00
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* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
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2000-01-26 06:58:53 +01:00
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* Portions Copyright (c) 1994, Regents of the University of California
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1996-07-09 08:22:35 +02:00
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*
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*
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* IDENTIFICATION
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2004-08-15 07:25:10 +02:00
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* $PostgreSQL: pgsql/src/backend/libpq/pqsignal.c,v 1.35 2004/08/15 05:25:10 tgl Exp $
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1996-07-09 08:22:35 +02:00
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*
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* NOTES
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1997-09-07 07:04:48 +02:00
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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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1996-07-09 08:22:35 +02:00
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*
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1997-09-07 07:04:48 +02:00
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* A NOTE ABOUT SIGNAL HANDLING ACROSS THE VARIOUS PLATFORMS.
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1996-11-18 03:25:09 +01:00
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*
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2001-08-24 16:07:50 +02:00
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* pg_config.h defines the macro HAVE_POSIX_SIGNALS for some platforms and
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1997-09-07 07:04:48 +02:00
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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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1996-11-18 03:25:09 +01:00
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*
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1997-09-07 07:04:48 +02:00
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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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1996-11-18 03:25:09 +01:00
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* ------------------------------------------------------------------------*/
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2004-01-27 01:45:26 +01:00
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1999-07-16 07:00:38 +02:00
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#include "postgres.h"
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2001-02-10 03:31:31 +01:00
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#include <signal.h>
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1999-07-16 01:04:24 +02:00
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#include "libpq/pqsignal.h"
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1996-07-09 08:22:35 +02:00
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2000-06-28 05:33:33 +02:00
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2004-05-30 00:48:23 +02:00
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#ifdef HAVE_SIGPROCMASK
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sigset_t UnBlockSig,
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BlockSig,
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AuthBlockSig;
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#else
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int UnBlockSig,
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BlockSig,
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AuthBlockSig;
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#endif
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2000-06-28 05:33:33 +02:00
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/*
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2001-09-08 03:10:21 +02:00
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* Initialize BlockSig, UnBlockSig, and AuthBlockSig.
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2000-06-28 05:33:33 +02:00
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*
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* BlockSig is the set of signals to block when we are trying to block
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* signals. This includes all signals we normally expect to get, but NOT
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* signals that should never be turned off.
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*
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2001-09-08 03:10:21 +02:00
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* AuthBlockSig is the set of signals to block during authentication;
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2001-09-21 19:06:12 +02:00
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* it's essentially BlockSig minus SIGTERM, SIGQUIT, SIGALRM.
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2001-09-08 03:10:21 +02:00
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*
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2000-06-28 05:33:33 +02:00
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* UnBlockSig is the set of signals to block when we don't want to block
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* signals (is this ever nonzero??)
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*/
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void
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pqinitmask(void)
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{
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#ifdef HAVE_SIGPROCMASK
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sigemptyset(&UnBlockSig);
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sigfillset(&BlockSig);
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2001-09-07 18:12:49 +02:00
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sigfillset(&AuthBlockSig);
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2001-03-22 05:01:46 +01:00
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2000-06-29 04:17:42 +02:00
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/*
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2001-03-22 05:01:46 +01:00
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* Unmark those signals that should never be blocked. Some of these
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* signal names don't exist on all platforms. Most do, but might as
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* well ifdef them all for consistency...
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2000-06-29 04:17:42 +02:00
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*/
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#ifdef SIGTRAP
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sigdelset(&BlockSig, SIGTRAP);
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2001-09-07 18:12:49 +02:00
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sigdelset(&AuthBlockSig, SIGTRAP);
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2000-06-29 04:17:42 +02:00
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#endif
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#ifdef SIGABRT
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2000-06-28 05:33:33 +02:00
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sigdelset(&BlockSig, SIGABRT);
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2001-09-07 18:12:49 +02:00
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sigdelset(&AuthBlockSig, SIGABRT);
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2000-06-29 04:17:42 +02:00
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#endif
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#ifdef SIGILL
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2000-06-28 05:33:33 +02:00
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sigdelset(&BlockSig, SIGILL);
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2001-09-07 18:12:49 +02:00
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sigdelset(&AuthBlockSig, SIGILL);
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2000-06-29 04:17:42 +02:00
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#endif
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#ifdef SIGFPE
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sigdelset(&BlockSig, SIGFPE);
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2001-09-07 18:12:49 +02:00
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sigdelset(&AuthBlockSig, SIGFPE);
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2000-06-29 04:17:42 +02:00
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#endif
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#ifdef SIGSEGV
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2000-06-28 05:33:33 +02:00
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sigdelset(&BlockSig, SIGSEGV);
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2001-09-07 18:12:49 +02:00
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sigdelset(&AuthBlockSig, SIGSEGV);
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2000-06-29 04:17:42 +02:00
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#endif
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#ifdef SIGBUS
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2000-06-28 05:33:33 +02:00
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sigdelset(&BlockSig, SIGBUS);
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2001-09-07 18:12:49 +02:00
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sigdelset(&AuthBlockSig, SIGBUS);
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2000-06-29 04:17:42 +02:00
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#endif
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#ifdef SIGSYS
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2000-06-28 05:33:33 +02:00
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sigdelset(&BlockSig, SIGSYS);
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2001-09-07 18:12:49 +02:00
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sigdelset(&AuthBlockSig, SIGSYS);
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2000-06-29 04:17:42 +02:00
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#endif
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#ifdef SIGCONT
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sigdelset(&BlockSig, SIGCONT);
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2001-09-07 18:12:49 +02:00
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sigdelset(&AuthBlockSig, SIGCONT);
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#endif
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#ifdef SIGTERM
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sigdelset(&AuthBlockSig, SIGTERM);
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#endif
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#ifdef SIGQUIT
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sigdelset(&AuthBlockSig, SIGQUIT);
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2000-06-29 04:17:42 +02:00
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#endif
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2001-09-21 19:06:12 +02:00
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#ifdef SIGALRM
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sigdelset(&AuthBlockSig, SIGALRM);
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#endif
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2000-06-28 05:33:33 +02:00
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#else
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UnBlockSig = 0;
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BlockSig = sigmask(SIGHUP) | sigmask(SIGQUIT) |
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sigmask(SIGTERM) | sigmask(SIGALRM) |
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sigmask(SIGINT) | sigmask(SIGUSR1) |
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sigmask(SIGUSR2) | sigmask(SIGCHLD) |
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sigmask(SIGWINCH) | sigmask(SIGFPE);
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2001-09-21 19:06:12 +02:00
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AuthBlockSig = sigmask(SIGHUP) |
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2001-09-07 18:12:49 +02:00
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sigmask(SIGINT) | sigmask(SIGUSR1) |
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sigmask(SIGUSR2) | sigmask(SIGCHLD) |
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sigmask(SIGWINCH) | sigmask(SIGFPE);
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2000-06-28 05:33:33 +02:00
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#endif
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}
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Here's an attempt at new socket and signal code for win32.
It works on the principle of turning sockets into non-blocking, and then
emulate blocking behaviour on top of that, while allowing signals to
run. Signals are now implemented using an event instead of APCs, thus
getting rid of the issue of APCs not being compatible with "old style"
sockets functions.
It also moves the win32 specific code away from pqsignal.h/c into
port/win32, and also removes the "thread style workaround" of the APC
issue previously in place.
In order to make things work, a few things are also changed in pgstat.c:
1) There is now a separate pipe to the collector and the bufferer. This
is required because the pipe will otherwise only be signalled in one of
the processes when the postmaster goes down. The MS winsock code for
select() must have some kind of workaround for this behaviour, but I
have found no stable way of doing that. You really are not supposed to
use the same socket from more than one process (unless you use
WSADuplicateSocket(), in which case the docs specifically say that only
one will be flagged).
2) The check for "postmaster death" is moved into a separate select()
call after the main loop. The previous behaviour select():ed on the
postmaster pipe, while later explicitly saying "we do NOT check for
postmaster exit inside the loop".
The issue was that the code relies on the same select() call seeing both
the postmaster pipe *and* the pgstat pipe go away. This does not always
happen, and it appears that useing WSAEventSelect() makes it even more
common that it does not.
Since it's only called when the process exits, I don't think using a
separate select() call will have any significant impact on how the stats
collector works.
Magnus Hagander
2004-04-12 18:19:18 +02:00
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/* Win32 signal handling is in backend/port/win32/signal.c */
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2004-01-27 01:45:26 +01:00
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#ifndef WIN32
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Here's an attempt at new socket and signal code for win32.
It works on the principle of turning sockets into non-blocking, and then
emulate blocking behaviour on top of that, while allowing signals to
run. Signals are now implemented using an event instead of APCs, thus
getting rid of the issue of APCs not being compatible with "old style"
sockets functions.
It also moves the win32 specific code away from pqsignal.h/c into
port/win32, and also removes the "thread style workaround" of the APC
issue previously in place.
In order to make things work, a few things are also changed in pgstat.c:
1) There is now a separate pipe to the collector and the bufferer. This
is required because the pipe will otherwise only be signalled in one of
the processes when the postmaster goes down. The MS winsock code for
select() must have some kind of workaround for this behaviour, but I
have found no stable way of doing that. You really are not supposed to
use the same socket from more than one process (unless you use
WSADuplicateSocket(), in which case the docs specifically say that only
one will be flagged).
2) The check for "postmaster death" is moved into a separate select()
call after the main loop. The previous behaviour select():ed on the
postmaster pipe, while later explicitly saying "we do NOT check for
postmaster exit inside the loop".
The issue was that the code relies on the same select() call seeing both
the postmaster pipe *and* the pgstat pipe go away. This does not always
happen, and it appears that useing WSAEventSelect() makes it even more
common that it does not.
Since it's only called when the process exits, I don't think using a
separate select() call will have any significant impact on how the stats
collector works.
Magnus Hagander
2004-04-12 18:19:18 +02:00
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2000-06-28 05:33:33 +02:00
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/*
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* Set up a signal handler
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*/
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1996-07-09 08:22:35 +02:00
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pqsigfunc
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pqsignal(int signo, pqsigfunc func)
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{
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2000-06-11 13:40:09 +02:00
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#if !defined(HAVE_POSIX_SIGNALS)
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1997-09-07 07:04:48 +02:00
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return signal(signo, func);
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1996-12-26 23:08:34 +01:00
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#else
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1997-09-07 07:04:48 +02:00
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struct sigaction act,
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1997-09-08 04:41:22 +02:00
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oact;
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1997-09-07 07:04:48 +02:00
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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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act.sa_flags |= SA_RESTART;
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2004-08-15 07:25:10 +02:00
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#ifdef SA_NOCLDSTOP
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if (signo == SIGCHLD)
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act.sa_flags |= SA_NOCLDSTOP;
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#endif
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1997-09-07 07:04:48 +02:00
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if (sigaction(signo, &act, &oact) < 0)
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1998-09-01 05:29:17 +02:00
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return SIG_ERR;
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return oact.sa_handler;
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2001-11-05 18:46:40 +01:00
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#endif /* !HAVE_POSIX_SIGNALS */
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1996-07-09 08:22:35 +02:00
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}
|
2004-05-30 00:48:23 +02:00
|
|
|
|
Here's an attempt at new socket and signal code for win32.
It works on the principle of turning sockets into non-blocking, and then
emulate blocking behaviour on top of that, while allowing signals to
run. Signals are now implemented using an event instead of APCs, thus
getting rid of the issue of APCs not being compatible with "old style"
sockets functions.
It also moves the win32 specific code away from pqsignal.h/c into
port/win32, and also removes the "thread style workaround" of the APC
issue previously in place.
In order to make things work, a few things are also changed in pgstat.c:
1) There is now a separate pipe to the collector and the bufferer. This
is required because the pipe will otherwise only be signalled in one of
the processes when the postmaster goes down. The MS winsock code for
select() must have some kind of workaround for this behaviour, but I
have found no stable way of doing that. You really are not supposed to
use the same socket from more than one process (unless you use
WSADuplicateSocket(), in which case the docs specifically say that only
one will be flagged).
2) The check for "postmaster death" is moved into a separate select()
call after the main loop. The previous behaviour select():ed on the
postmaster pipe, while later explicitly saying "we do NOT check for
postmaster exit inside the loop".
The issue was that the code relies on the same select() call seeing both
the postmaster pipe *and* the pgstat pipe go away. This does not always
happen, and it appears that useing WSAEventSelect() makes it even more
common that it does not.
Since it's only called when the process exits, I don't think using a
separate select() call will have any significant impact on how the stats
collector works.
Magnus Hagander
2004-04-12 18:19:18 +02:00
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|
#endif /* WIN32 */
|