From 2fe44bbd7885dcaa72e85df9bc2881cef78feb78 Mon Sep 17 00:00:00 2001
From: Gerhard Rieger <gerhard@dest-unreach.org>
Date: Sat, 30 Oct 2021 18:10:27 +0200
Subject: [PATCH] Fixed -r, -R to named pipe "No such device or address" error

---
 CHANGES |  5 +++++
 socat.c | 22 ++++++++++++++++++++--
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/CHANGES b/CHANGES
index 8866ccf..7c10ed4 100644
--- a/CHANGES
+++ b/CHANGES
@@ -40,6 +40,11 @@ Corrections:
 	Test: SNIFF_RIGHT_TO_LEFT
 	Thanks to 1314 gsf for reporting this bug and sending a patch.
 
+	Options -r and -R, when opening a named pipe that has no actual reader,
+	failed with "No such device or address". To solve this problem, Socat
+	now opens the pipe in rw-Mode.
+	Thanks to Cody J.Soultz for sending a patch.
+
 Testing:
 	Prevent the TIMESTAMP tests from sporadically failing due do seconds
 	overflow
diff --git a/socat.c b/socat.c
index 8c9b841..b7a9b61 100644
--- a/socat.c
+++ b/socat.c
@@ -191,8 +191,17 @@ int main(int argc, const char *argv[]) {
 #ifdef O_LARGEFILE
 					  O_LARGEFILE|
 #endif
-					  O_NONBLOCK, 0664)) < 0)
+					  O_NONBLOCK, 0664)) < 0) {
+	    if (errno == ENXIO) {
+	       if ((socat_opts.sniffleft = Open(a, O_CREAT|O_RDWR|O_APPEND|
+#ifdef O_LARGEFILE
+						O_LARGEFILE|
+#endif
+						O_NONBLOCK, 0664)) > 0)
+		  break; 	/* try to open pipe rdwr */
+	    }
 	    Error2("option -r \"%s\": %s", a, strerror(errno));
+         }
 	 break;
       case 'R': if (arg1[0][2]) {
 	    a = *arg1+2;
@@ -207,8 +216,17 @@ int main(int argc, const char *argv[]) {
 #ifdef O_LARGEFILE
 					   O_LARGEFILE|
 #endif
-					   O_NONBLOCK, 0664)) < 0)
+					   O_NONBLOCK, 0664)) < 0) {
+	    if (errno == ENXIO) {
+	       if ((socat_opts.sniffright = Open(a, O_CREAT|O_RDWR|O_APPEND|
+#ifdef O_LARGEFILE
+						O_LARGEFILE|
+#endif
+						O_NONBLOCK, 0664)) > 0)
+		  break; 	/* try to open pipe rdwr */
+	    }
 	    Error2("option -R \"%s\": %s", a, strerror(errno));
+         }
 	 break;
       case 'b': if (arg1[0][2]) {
 	    a = *arg1+2;