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/*-------------------------------------------------------------------------
*
* legacy-pqsignal.c
* reliable BSD-style signal(2) routine stolen from RWW who stole it
* from Stevens...
*
* Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/interfaces/libpq/legacy-pqsignal.c
*
*-------------------------------------------------------------------------
*/
#include "postgres_fe.h"
#include <signal.h>
/*
* This version of pqsignal() exists only because pre-9.3 releases
* of libpq exported pqsignal(), and some old client programs still
* depend on that. (Since 9.3, clients are supposed to get it from
* libpgport instead.)
*
* Because it is only intended for backwards compatibility, we freeze it
* with the semantics it had in 9.2; in particular, this has different
* behavior for SIGALRM than the version in src/port/pqsignal.c.
*
* libpq itself does not use this, nor does anything else in our code.
*
* src/include/port.h will #define pqsignal as pqsignal_fe,
* but here we want to export just plain "pqsignal". We can't rely on
* port.h's extern declaration either. (The point of that #define
* is to ensure that no in-tree code accidentally calls this version.)
*/
#undef pqsignal
extern pqsigfunc pqsignal(int signo, pqsigfunc func);
pqsigfunc
pqsignal(int signo, pqsigfunc func)
{
#ifndef WIN32
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;
#else /* WIN32 */
return signal(signo, func);
#endif
}
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