From 9f34ef6a0b1fd5545112498e2363d784cee8e42e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20Ankarstr=C3=B6m?= <john@ankarstrom.se>
Date: Wed, 14 Jul 2021 18:43:20 +0200
Subject: Rename rtty to rio, rd to rtty

---
 rio.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 rio.c

(limited to 'rio.c')

diff --git a/rio.c b/rio.c
new file mode 100644
index 0000000..88ef214
--- /dev/null
+++ b/rio.c
@@ -0,0 +1,88 @@
+#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], *bi, *bo;
+	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");
+
+	FD_ZERO(&rfds0);
+	FD_ZERO(&rfds1);
+
+	tv.tv_sec = 0;
+	tv.tv_usec = 1;
+
+	for(;;){
+		/*
+		 * User input is read from standard in and copied the
+		 * input pipe. It is saved in bufin for later use.
+		 */
+		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);
+		}
+
+		/*
+		 * System output is read from the output pipe and copied
+		 * to standard out for the user to see.
+		 */
+		FD_SET(fdout, &rfds1);
+		if(select(fdout+1, &rfds1, NULL, NULL, &tv) > 0){
+			nout = read(fdout, bufout, MAXBUF);
+			if(!nout) continue;
+			bufout[nout] = 0;
+
+			/*
+			 * Bufin and bufout are copied to the temporary
+			 * pointers bi and bo. Bo is incremented in order
+			 * to skip any potential repetition of the command
+			 * given by the user on standard in. (It is assumed
+			 * that the typed command fits in bufin, i.e. is
+			 * not larger than MAXBUF.)
+			 */
+			bi = bufin;
+			bo = bufout;
+			for(;;){
+				if(*bo == '\n'){
+					bo++;
+					break;
+				}
+				if(*bo == 13){
+					bo++;
+					continue;
+				}
+				if(*bi != *bo){
+					bo = bufout;
+					break;
+				}
+				bi++; bo++;
+			}
+
+			/*
+			 * Bo is printed and bufin is cleared, so as not
+			 * to perform the skip again, incorrectly.
+			 */
+			printf("%s", bo);
+			fflush(stdout);
+			bufin[0] = 0;
+		}
+	}
+
+}
-- 
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