pqsignal.c

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/*-------------------------------------------------------------------------
 *
 * pqsignal.c
 *    Backend signal(2) support (see also src/port/pqsignal.c)
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/backend/libpq/pqsignal.c
 *
 * ------------------------------------------------------------------------
 */
 
#include "postgres.h"
 
#include "libpq/pqsignal.h"
 
 
/* Global variables */
sigset_t    UnBlockSig,
            BlockSig,
            StartupBlockSig;
 
 
/*
 * Initialize BlockSig, UnBlockSig, and StartupBlockSig.
 *
 * BlockSig is the set of signals to block when we are trying to block
 * signals.  This includes all signals we normally expect to get, but NOT
 * signals that should never be turned off.
 *
 * StartupBlockSig is the set of signals to block during startup packet
 * collection; it's essentially BlockSig minus SIGTERM, SIGQUIT, SIGALRM.
 *
 * UnBlockSig is the set of signals to block when we don't want to block
 * signals.
 */
void
pqinitmask(void)
{
    sigemptyset(&UnBlockSig);
 
    /* Note: InitializeLatchSupport() modifies UnBlockSig. */
 
    /* First set all signals, then clear some. */
    sigfillset(&BlockSig);
    sigfillset(&StartupBlockSig);
 
    /*
     * Unmark those signals that should never be blocked. Some of these signal
     * names don't exist on all platforms.  Most do, but might as well ifdef
     * them all for consistency...
     */
#ifdef SIGTRAP
    sigdelset(&BlockSig, SIGTRAP);
    sigdelset(&StartupBlockSig, SIGTRAP);
#endif
#ifdef SIGABRT
    sigdelset(&BlockSig, SIGABRT);
    sigdelset(&StartupBlockSig, SIGABRT);
#endif
#ifdef SIGILL
    sigdelset(&BlockSig, SIGILL);
    sigdelset(&StartupBlockSig, SIGILL);
#endif
#ifdef SIGFPE
    sigdelset(&BlockSig, SIGFPE);
    sigdelset(&StartupBlockSig, SIGFPE);
#endif
#ifdef SIGSEGV
    sigdelset(&BlockSig, SIGSEGV);
    sigdelset(&StartupBlockSig, SIGSEGV);
#endif
#ifdef SIGBUS
    sigdelset(&BlockSig, SIGBUS);
    sigdelset(&StartupBlockSig, SIGBUS);
#endif
#ifdef SIGSYS
    sigdelset(&BlockSig, SIGSYS);
    sigdelset(&StartupBlockSig, SIGSYS);
#endif
#ifdef SIGCONT
    sigdelset(&BlockSig, SIGCONT);
    sigdelset(&StartupBlockSig, SIGCONT);
#endif
 
/* Signals unique to startup */
#ifdef SIGQUIT
    sigdelset(&StartupBlockSig, SIGQUIT);
#endif
#ifdef SIGTERM
    sigdelset(&StartupBlockSig, SIGTERM);
#endif
#ifdef SIGALRM
    sigdelset(&StartupBlockSig, SIGALRM);
#endif
}