erts: Remove truncation of http packet parsing and return error instead

This is a slight modification of previous commit by Steve Vinoski

For backward compatibility of old users of decode_packet, I think it's enough
to return error instead of keeping the old line truncation behaviour.

4 files changed, 21 insertions, 20 deletions

diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index 42a4e6a999..1ea88a185f 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -724,9 +724,12 @@ false</pre>
                 size limit.</p>
               </item>
               <tag><c>{line_length, integer()}</c></tag>
-              <item><p>Applies only to line oriented protocols
-                (<c>line</c>, <c>http</c>). Lines longer than this
-                will be truncated.</p>
+              <item><p>For packet type <c>line</c>, truncate lines longer
+	      than the indicated length.</p>
+	      <p>Option <c>line_length</c> also applies to <c>http*</c> 
+	      packet types as an alias for option <c>packet_size</c> in the
+	      case when <c>packet_size</c> itself is not set. This usage is
+	      only intended for backward compatibility.</p>
               </item>
             </taglist>
         <pre>
diff --git a/erts/emulator/beam/packet_parser.c b/erts/emulator/beam/packet_parser.c
index 8c1662dc6f..4d4b6ea196 100644
--- a/erts/emulator/beam/packet_parser.c
+++ b/erts/emulator/beam/packet_parser.c
@@ -405,18 +405,22 @@ int packet_get_length(enum PacketParseType htype,
             const char* ptr1 = ptr;
             int   len = plen;
             
+	    if (!max_plen) {
+		/* This is for backward compatibility with old user of decode_packet
+		 * that might use option 'line_length' to limit accepted length of
+		 * http lines.
+		 */
+		max_plen = trunc_len;
+	    }
+
             while (1) {
                 const char* ptr2 = memchr(ptr1, '\n', len);
                 
                 if (ptr2 == NULL) {
                     if (max_plen != 0) {
-                        if (n > max_plen) /* packet full */
+                        if (n >= max_plen) /* packet full */
                             goto error;
                     }
-                    else if (n >= trunc_len && trunc_len!=0) { /* buffer full */
-                        plen = trunc_len;
-                        goto done;
-                    }
                     goto more;
                 }
                 else {
@@ -425,8 +429,6 @@ int packet_get_length(enum PacketParseType htype,
                     if (*statep == 0) {
                         if (max_plen != 0 && plen > max_plen)
                             goto error;
-                        if (plen >= trunc_len && trunc_len != 0)
-                            plen = trunc_len;
                         goto done;
                     }
 
@@ -439,18 +441,12 @@ int packet_get_length(enum PacketParseType htype,
                         else {
                             if (max_plen != 0 && plen > max_plen)
                                 goto error;
-                            if (plen >= trunc_len && trunc_len != 0)
-                                plen = trunc_len;
                             goto done;
                         }
                     }
                     else {
                         if (max_plen != 0 && plen > max_plen)
                             goto error;
-                        if (plen >= trunc_len && trunc_len != 0) {
-                            plen = trunc_len;
-                            goto done;
-                        }
                         goto more;
                     }
                 }
diff --git a/erts/emulator/test/decode_packet_SUITE.erl b/erts/emulator/test/decode_packet_SUITE.erl
index 55ef05079f..4acbe8c6e0 100644
--- a/erts/emulator/test/decode_packet_SUITE.erl
+++ b/erts/emulator/test/decode_packet_SUITE.erl
@@ -596,11 +596,9 @@ otp_9389(Config) when is_list(Config) ->
     {more, undefined} = erlang:decode_packet(httph, Rest2, Opts),
     {ok, {http_header,_,"Link",_,Link}, Rest3} =
         erlang:decode_packet(httph, list_to_binary([Rest2, Pkt2]), Opts),
-    true = (length(Link) =< 3000),
-    {ok, {http_error, _}, Rest4} = erlang:decode_packet(httph, Rest3, Opts),
-    {ok, {http_error, _}, Rest5} = erlang:decode_packet(httph, Rest4, Opts),
+    true = (length(Link) > 8000),
     {ok, {http_header,_,'Content-Length',_,"0"}, <<"\r\n">>} =
-        erlang:decode_packet(httph, Rest5, Opts),
+        erlang:decode_packet(httph, Rest3, Opts),
     ok.
 
 otp_9389_line(doc) -> ["Verify packet_size works correctly for line mode"];
diff --git a/lib/kernel/doc/src/inet.xml b/lib/kernel/doc/src/inet.xml
index fad5af85bb..1a05b4ba99 100644
--- a/lib/kernel/doc/src/inet.xml
+++ b/lib/kernel/doc/src/inet.xml
@@ -573,6 +573,10 @@ fe80::204:acff:fe17:bf38
               is longer than the max allowed length, the packet is
               considered invalid. The same happens if the packet header
               is too big for the socket receive buffer.</p>
+	    <p>For line oriented protocols (<c>line</c>,<c>http*</c>),
+	    option <c>packet_size</c> also guarantees that lines up to the
+	    indicated length are accepted and not considered invalid due
+	    to internal buffer limitations.</p>
           </item>
           <tag><c>{read_packets, Integer}</c>(UDP sockets)</tag>
           <item>