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/*
Unix SMB/CIFS implementation.
signal handling functions
Copyright (C) Andrew Tridgell 1998
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "util/util.h"
#include <sys/types.h>
#include <sys/wait.h>
/**
* @file
* @brief Signal handling
*/
/****************************************************************************
Catch child exits and reap the child zombie status.
****************************************************************************/
static void sig_cld(int signum)
{
while (waitpid((pid_t)-1,(int *)NULL, WNOHANG) > 0)
;
/*
* Turns out it's *really* important not to
* restore the signal handler here if we have real POSIX
* signal handling. If we do, then we get the signal re-delivered
* immediately - hey presto - instant loop ! JRA.
*/
#if !defined(HAVE_SIGACTION)
CatchSignal(SIGCLD, sig_cld);
#endif
}
/****************************************************************************
catch child exits - leave status;
****************************************************************************/
static void sig_cld_leave_status(int signum)
{
/*
* Turns out it's *really* important not to
* restore the signal handler here if we have real POSIX
* signal handling. If we do, then we get the signal re-delivered
* immediately - hey presto - instant loop ! JRA.
*/
#if !defined(HAVE_SIGACTION)
CatchSignal(SIGCLD, sig_cld_leave_status);
#endif
}
/**
Block sigs.
**/
void BlockSignals(bool block, int signum)
{
#ifdef HAVE_SIGPROCMASK
sigset_t set;
sigemptyset(&set);
sigaddset(&set,signum);
sigprocmask(block?SIG_BLOCK:SIG_UNBLOCK,&set,NULL);
#elif defined(HAVE_SIGBLOCK)
if (block) {
sigblock(sigmask(signum));
} else {
sigsetmask(siggetmask() & ~sigmask(signum));
}
#else
/* yikes! This platform can't block signals? */
static int done;
if (!done) {
DEBUG(0,("WARNING: No signal blocking available\n"));
done=1;
}
#endif
}
/**
Catch a signal. This should implement the following semantics:
1) The handler remains installed after being called.
2) The signal should be blocked during handler execution.
**/
void (*CatchSignal(int signum,void (*handler)(int )))(int)
{
#ifdef HAVE_SIGACTION
struct sigaction act;
struct sigaction oldact;
ZERO_STRUCT(act);
act.sa_handler = handler;
#ifdef SA_RESTART
/*
* We *want* SIGALRM to interrupt a system call.
*/
if(signum != SIGALRM)
act.sa_flags = SA_RESTART;
#endif
sigemptyset(&act.sa_mask);
sigaddset(&act.sa_mask,signum);
sigaction(signum,&act,&oldact);
return oldact.sa_handler;
#else /* !HAVE_SIGACTION */
/* FIXME: need to handle sigvec and systems with broken signal() */
return signal(signum, handler);
#endif
}
/**
Ignore SIGCLD via whatever means is necessary for this OS.
**/
void CatchChild(void)
{
CatchSignal(SIGCLD, sig_cld);
}
/**
Catch SIGCLD but leave the child around so it's status can be reaped.
**/
void CatchChildLeaveStatus(void)
{
CatchSignal(SIGCLD, sig_cld_leave_status);
}
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