1 files changed, 98 insertions, 0 deletions
diff --git a/src/pipeutils.c b/src/pipeutils.c
new file mode 100644
index 0000000..75302cb
--- /dev/null
+++ b/src/pipeutils.c
@@ -0,0 +1,98 @@
+/* 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);
+}