From a83039b2c93a3fedcecde17489221264f5abdfea Mon Sep 17 00:00:00 2001
From: bluhm <bluhm@openbsd.org>
Date: Fri, 28 Jun 2024 21:07:27 +0000
Subject: [PATCH] Test writing to socket pair closed by the other side.  This
 must trigger EPIPE error.

with and OK mvs@
---
 regress/sys/kern/unp-write-closed/Makefile    |  5 ++
 .../kern/unp-write-closed/unp-write-closed.c  | 83 +++++++++++++++++++
 2 files changed, 88 insertions(+)
 create mode 100644 regress/sys/kern/unp-write-closed/Makefile
 create mode 100644 regress/sys/kern/unp-write-closed/unp-write-closed.c

diff --git a/regress/sys/kern/unp-write-closed/Makefile b/regress/sys/kern/unp-write-closed/Makefile
new file mode 100644
index 00000000000..83299417480
--- /dev/null
+++ b/regress/sys/kern/unp-write-closed/Makefile
@@ -0,0 +1,5 @@
+#	$OpenBSD: Makefile,v 1.1.1.1 2024/06/28 21:07:27 bluhm Exp $
+
+PROG=	unp-write-closed
+
+.include <bsd.regress.mk>
diff --git a/regress/sys/kern/unp-write-closed/unp-write-closed.c b/regress/sys/kern/unp-write-closed/unp-write-closed.c
new file mode 100644
index 00000000000..51e84ec7c65
--- /dev/null
+++ b/regress/sys/kern/unp-write-closed/unp-write-closed.c
@@ -0,0 +1,83 @@
+/*	$OpenBSD: unp-write-closed.c,v 1.1.1.1 2024/06/28 21:07:27 bluhm Exp $	*/
+/*
+ * Copyright (c) 2024 Vitaliy Makkoveev <mvs@openbsd.org>
+ * Copyright (c) 2024 Alenander Bluhm <bluhm@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+
+#include <err.h>
+#include <errno.h>
+#include <signal.h>
+#include <unistd.h>
+
+sig_atomic_t done = 0;
+
+void
+handler(int sigraised)
+{
+	done = 1;
+}
+
+int
+main(int argc, char *argv[])
+{
+	int i, s[2], status;
+	pid_t pid;
+
+	if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
+		err(1, "signal pipe");
+	if (signal(SIGALRM, handler) == SIG_ERR)
+		err(1, "signal alrm");
+	alarm(30);
+
+	while (!done) {
+		if (socketpair(AF_UNIX, SOCK_STREAM, 0, s) < 0)
+			err(1, "socketpair");
+
+		switch ((pid = fork())) {
+		case -1:
+			err(1, "fork");
+		case 0:
+			if (close(s[0]) < 0)
+				err(1, "child close 0");
+			if (close(s[1]) < 0)
+				err(1, "child close 1");
+			return 0;
+		default:
+			if (close(s[1]) < 0)
+				err(1, "parent close 1");
+			for (i = 1000000; i > 0; i--) {
+				if (write(s[0], "1", 1) < 0)
+					break;
+			}
+			if (i <= 0)
+				errx(1, "write did not fail");
+			if (errno != EPIPE)
+				err(1, "write");
+			if (close(s[0]) < 0)
+				err(1, "parent close 1");
+			if (waitpid(pid, &status, 0) < 0)
+				err(1, "waitpid");
+			if (status != 0)
+				errx(1, "child status %d", status);
+			break;
+		}
+	}
+
+	return 0;
+}
-- 
2.20.1