[Nbd] [PATCH] Docs: proto.md: Clarify NUL in export name

[Alex Bligh <alex@...872...>]

Clarify that

* The name is not NUL terminated (not just that the length
  'does not include NUL termination' which might be taken to mean
  there is NUL termination but the length doesn't include it.

* The name cannot itself include embedded NUL characters (despite
  it not being NUL terminated).

Signed-off-by: Alex Bligh <alex@...872...>
---
 doc/proto.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/doc/proto.md b/doc/proto.md
index c1e05c5..7729051 100644
--- a/doc/proto.md
+++ b/doc/proto.md
@@ -292,7 +292,8 @@ of the newstyle negotiation.
     haggling, and proceed to the transmission phase. Data: name of the
     export, free-form UTF-8 text (subject to limitations by server
     implementation). The length of the name is determined from the
-    option header, and does NOT include a NUL terminator.  If the
+    option header. The name is not NUL terminated, and may not
+    contain embedded NUL characters. If the
     chosen export does not exist or requirements for the chosen export
     are not met (e.g., the client did not negotiate TLS for an export
     where the server requires it), the server should close the
-- 
1.9.1