commit 585e2e89a9d00df6ffe9a704f3de0f003b2b8b66
from: Martijn van Duren <martijn@openbsd.org>
date: Mon Apr  1 16:06:49 2019 UTC

This should be && and not ||

commit - a211223d04eb8add0ba4b89c31473196903d7296
commit + 585e2e89a9d00df6ffe9a704f3de0f003b2b8b66
blob - 511fe85a8f5024c97cd39a4467cb95e31180c0b4
blob + 6b067f72aa3eba6453a448f0270bbad62994122e
--- smtp_proc.c
+++ smtp_proc.c
@@ -386,7 +386,7 @@ smtp_write(int fd, short event, void *arg)
 	}
 	wlen = write(fd, buf->buf, buf->buflen);
 	if (wlen == -1) {
-		if (errno != EAGAIN || errno != EINTR)
+		if (errno != EAGAIN && errno != EINTR)
 			fatal("Failed to write to smtpd");
 		event_add(&ev, NULL);
 		return;