pqsignal.c File Reference

#include "c.h"
#include <signal.h>
#include <unistd.h>
#include "libpq/pqsignal.h"
#include "miscadmin.h"

Include dependency graph for pqsignal.c:

Go to the source code of this file.

Macros
#define	PG_NSIG   (64) /* XXX: wild guess */

Functions
	StaticAssertDecl (SIGUSR2< PG_NSIG, "SIGUSR2 >= PG_NSIG")
static void	wrapper_handler (SIGNAL_ARGS)
pqsigfunc	pqsignal (int signo, pqsigfunc func)

Variables
static volatile pqsigfunc	pqsignal_handlers [PG_NSIG]

Macro Definition Documentation

PG_NSIG

#define PG_NSIG   (64) /* XXX: wild guess */

Definition at line 63 of file pqsignal.c.

Function Documentation

pqsignal()

pqsigfunc pqsignal	(	int	signo,
		pqsigfunc	func
	)

Definition at line 129 of file pqsignal.c.

{
    pqsigfunc   orig_func = pqsignal_handlers[signo];   /* assumed atomic */
#if !(defined(WIN32) && defined(FRONTEND))
    struct sigaction act,
                oact;
#else
    pqsigfunc   ret;
#endif
 
    Assert(signo < PG_NSIG);
 
    if (func != SIG_IGN && func != SIG_DFL)
    {
        pqsignal_handlers[signo] = func;    /* assumed atomic */
        func = wrapper_handler;
    }
 
#if !(defined(WIN32) && defined(FRONTEND))
    act.sa_handler = func;
    sigemptyset(&act.sa_mask);
    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;
    else if (oact.sa_handler == wrapper_handler)
        return orig_func;
    else
        return oact.sa_handler;
#else
    /* Forward to Windows native signal system. */
    if ((ret = signal(signo, func)) == wrapper_handler)
        return orig_func;
    else
        return ret;
#endif
}

References SIG_ERR, SIGALRM, and SIGCHLD.

Referenced by ApplyLauncherMain(), autoprewarm_database_main(), autoprewarm_main(), AutoVacWorkerMain(), BackendInitialize(), BackgroundWorkerMain(), BackgroundWriterMain(), bootstrap_signals(), CheckpointerMain(), disable_sigpipe_trap(), do_start(), InitializeLatchSupport(), InitializeTimeouts(), InitPostmasterChild(), main(), make_temp_sockdir(), OpenPipeStream(), ParallelApplyWorkerMain(), ParallelBackupStart(), ParallelWorkerMain(), pg_crc32c_armv8_available(), PgArchiverMain(), plperl_init_interp(), PostgresMain(), PostmasterDeathSignalInit(), PostmasterMain(), ReplSlotSyncWorkerMain(), restore_sigpipe_trap(), set_cancel_handler(), setalarm(), setup_cancel_handler(), setup_signals(), SetupApplyOrSyncWorker(), ShutdownLatchSupport(), signal_remove_temp(), sigTermHandler(), StartupProcessMain(), SysLoggerMain(), test_shm_mq_main(), trap_sigint_during_startup(), trapsig(), WalReceiverMain(), WalSndSignals(), WalSummarizerMain(), WalWriterMain(), and worker_spi_main().

StaticAssertDecl()

StaticAssertDecl

(

)

wrapper_handler()

static void wrapper_handler ( SIGNAL_ARGS  )

static

Definition at line 87 of file pqsignal.c.

{
    int         save_errno = errno;
 
#ifndef FRONTEND
 
    /*
     * We expect processes to set MyProcPid before calling pqsignal() or
     * before accepting signals.
     */
    Assert(MyProcPid);
    Assert(MyProcPid != PostmasterPid || !IsUnderPostmaster);
 
    if (unlikely(MyProcPid != (int) getpid()))
    {
        pqsignal(postgres_signal_arg, SIG_DFL);
        raise(postgres_signal_arg);
        return;
    }
#endif
 
    (*pqsignal_handlers[postgres_signal_arg]) (postgres_signal_arg);
 
    errno = save_errno;
}

Variable Documentation

pqsignal_handlers

volatile pqsigfunc pqsignal_handlers[PG_NSIG]

static

Definition at line 72 of file pqsignal.c.