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/* pipeutils.c -- Utilities for using pipes as signals
This file is part of Redshift.
Redshift 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.
Redshift 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 Redshift. If not, see <http://www.gnu.org/licenses/>.
Copyright (c) 2017 Jon Lund Steffensen <jonlst@gmail.com>
*/
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#ifndef _WIN32
/* Create non-blocking set of pipe fds. */
int
pipeutils_create_nonblocking(int pipefds[2])
{
int r = pipe(pipefds);
if (r == -1) {
perror("pipe");
return -1;
}
int flags = fcntl(pipefds[0], F_GETFL);
if (flags == -1) {
perror("fcntl");
close(pipefds[0]);
close(pipefds[1]);
return -1;
}
r = fcntl(pipefds[0], F_SETFL, flags | O_NONBLOCK);
if (r == -1) {
perror("fcntl");
close(pipefds[0]);
close(pipefds[1]);
return -1;
}
flags = fcntl(pipefds[1], F_GETFL);
if (flags == -1) {
perror("fcntl");
close(pipefds[0]);
close(pipefds[1]);
return -1;
}
r = fcntl(pipefds[1], F_SETFL, flags | O_NONBLOCK);
if (r == -1) {
perror("fcntl");
close(pipefds[0]);
close(pipefds[1]);
return -1;
}
return 0;
}
#else /* _WIN32 */
/* Create non-blocking set of pipe fds.
Not supported on Windows! Always fails. */
int
pipeutils_create_nonblocking(int pipefds[2])
{
return -1;
}
#endif
/* Signal on write-end of pipe. */
void
pipeutils_signal(int write_fd)
{
write(write_fd, "", 1);
}
/* Mark signal as handled on read-end of pipe. */
void
pipeutils_handle_signal(int read_fd)
{
char data;
read(read_fd, &data, 1);
}
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