Merge branch 'rickard/null-chars/ERL-370/OTP-14543'

* rickard/null-chars/ERL-370/OTP-14543:
  Don't allow null chars in various strings

Conflicts:
	erts/emulator/beam/erl_alloc.types
	erts/preloaded/ebin/erlang.beam

1 files changed, 24 insertions, 0 deletions

diff --git a/lib/stdlib/doc/src/filelib.xml b/lib/stdlib/doc/src/filelib.xml
index 158cf4b266..5e631aac21 100644
--- a/lib/stdlib/doc/src/filelib.xml
+++ b/lib/stdlib/doc/src/filelib.xml
@@ -45,6 +45,30 @@
 
     <p>For more information about raw filenames, see the
       <seealso marker="kernel:file"><c>file</c></seealso> module.</p>
+
+    <note>
+      <p>
+	Functionality in this module generally assumes valid input and
+	does not necessarily fail on input that does not use a valid
+	encoding, but may instead very likely produce invalid output.
+      </p>
+      <p>
+	File operations used to accept filenames containing
+	null characters (integer value zero). This caused
+	the name to be truncated and in some cases arguments
+	to primitive operations to be mixed up. Filenames
+	containing null characters inside the filename
+	are now <em>rejected</em> and will cause primitive
+	file operations to fail.
+      </p>
+    </note>
+    <warning><p>
+      Currently null characters at the end of the filename
+      will be accepted by primitive file operations. Such
+      filenames are however still documented as invalid. The
+      implementation will also change in the future and
+      reject such filenames.
+    </p></warning>
   </description>
 
   <datatypes>