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// nullmailer -- a simple relay-only MTA
// Copyright (C) 2017 Bruce Guenter <bruce@untroubled.org>
//
// 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 2 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, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
// You can contact me at <bruce@untroubled.org>. There is also a mailing list
// available to discuss this package. To subscribe, send an email to
// <nullmailer-subscribe@lists.untroubled.org>.
#include <sys/types.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include "selfpipe.h"
static int fds[2] = { -1, -1 };
static int fcntl_fl_on(int fd, int flag)
{
int flags;
int newflags;
if ((flags = fcntl(fd, F_GETFL, 0)) == -1)
return 0;
if ((newflags = flags | flag) != flags)
if (fcntl(fd, F_SETFL, newflags))
return 0;
return 1;
}
selfpipe::selfpipe()
{
if (fds[0] < 0) {
if (pipe(fds) != -1) {
if (fcntl_fl_on(fds[0], O_NONBLOCK)
&& fcntl_fl_on(fds[1], O_NONBLOCK)
&& fcntl_fl_on(fds[1], FD_CLOEXEC)
&& fcntl_fl_on(fds[1], FD_CLOEXEC))
return;
close(fds[0]);
close(fds[1]);
}
fds[0] = fds[1] = -1;
}
}
selfpipe::operator bool() const
{
return fds[0] >= 0;
}
static void catcher(int sig)
{
signal(sig, catcher);
write(fds[1], &sig, sizeof sig);
}
void selfpipe::catchsig(int sig)
{
signal(sig, catcher);
}
int selfpipe::caught()
{
int buf;
if (read(fds[0], &buf, sizeof buf) == sizeof buf)
return buf;
return 0;
}
int selfpipe::waitsig(int timeout)
{
if (timeout > 0) {
fd_set fdset;
FD_ZERO(&fdset);
FD_SET(fds[0], &fdset);
struct timeval tv;
tv.tv_sec = timeout;
tv.tv_usec = 0;
int s;
while ((s = select(fds[0] + 1, &fdset, 0, 0,
(timeout <= 0) ? 0 : &tv)) == -1) {
if (errno != EINTR)
return -1;
}
if (s != 1)
return 0;
}
return caught();
}
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