From 57c74154571d14dcebb92ad0f9ff6369728163da Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Wed, 14 Jul 2021 11:08:56 +0200
Subject: Add rtty.c

---
 rtty.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 rtty.c

diff --git a/rtty.c b/rtty.c
new file mode 100644
index 0000000..766912f
--- /dev/null
+++ b/rtty.c
@@ -0,0 +1,59 @@
+#include <err.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/select.h>
+#include <unistd.h>
+
+#define MAXBUF 2048
+
+int
+main()
+{
+	char bufin[MAXBUF], bufout[MAXBUF];
+	fd_set rfds0, rfds1;
+	int c, fdin, fdout, flags, i, nin, nout, state;
+	struct timeval tv;
+
+	if(!(fdin = open("/var/tmp/r.in", O_WRONLY)))
+		err(1, "open");
+	if(!(fdout = open("/var/tmp/r.out", O_RDONLY)))
+		err(1, "open");
+
+	flags = fcntl(0, F_GETFL, 0);
+	flags |= O_NONBLOCK;
+	fcntl(0, F_SETFL, flags);
+
+	FD_ZERO(&rfds0);
+	FD_ZERO(&rfds1);
+
+	tv.tv_sec = 0;
+	tv.tv_usec = 1;
+
+	for(;;){
+		/* Read from named pipe (out) and print on standard in. */
+		FD_SET(fdout, &rfds1);
+		if(select(fdout+1, &rfds1, NULL, NULL, &tv) > 0){
+			nout = read(fdout, bufout, MAXBUF);
+			bufout[nout] = 0;
+
+			/* Ignore repetition of typed command. */
+			if(strcmp(bufout, bufin) == 0)
+				bufin[0] = 0;
+			else{
+				printf("%s", bufout);
+				fflush(stdout);
+			}
+		}
+
+		/* Read from standard in and print on named pipe (in). */
+		FD_SET(0, &rfds0);
+		if(select(0+1, &rfds0, NULL, NULL, &tv) > 0){
+			nout = read(0, bufin, MAXBUF);
+			bufin[nout] = 0;
+			dprintf(fdin, "%s", bufin);
+			fflush(stdout);
+		}
+	}
+
+}
-- 
cgit v1.2.3