From 32dd52d5b35793470930a2c7a7394316bca5abd4 Mon Sep 17 00:00:00 2001
From: Hans Bolinder <hasse@erlang.org>
Date: Wed, 20 Oct 2010 15:39:20 +0200
Subject: Fix a bug concerning bchunk(), match() and select()

If a Dets table was closed after calling bchunk/2, match/1,3,
match_object/1,3, or select/1,3 and then opened again, a subsequent
call using the returned continuation would normally return a reply.
This bug has fixed; now the call fails with reason 'badarg'.
---
 lib/stdlib/src/dets.erl | 71 ++++++++++++++++++++++++++-----------------------
 1 file changed, 37 insertions(+), 34 deletions(-)

(limited to 'lib/stdlib/src')

diff --git a/lib/stdlib/src/dets.erl b/lib/stdlib/src/dets.erl
index 4584b8184f..cf68958a9f 100644
--- a/lib/stdlib/src/dets.erl
+++ b/lib/stdlib/src/dets.erl
@@ -147,6 +147,7 @@
 	 bin,         % small chunk not consumed, or 'eof' at end-of-file
 	 alloc,       % the part of the file not yet scanned, mostly a binary
 	 tab,
+         proc,        % the pid of the Dets process
          match_program % true | compiled_match_spec() | undefined
 	 }).
 
@@ -208,8 +209,6 @@ all() ->
 
 bchunk(Tab, start) ->
     badarg(treq(Tab, {bchunk_init, Tab}), [Tab, start]);
-bchunk(Tab, #dets_cont{bin = eof, tab = Tab}) ->
-    '$end_of_table';
 bchunk(Tab, #dets_cont{what = bchunk, tab = Tab} = State) ->
     badarg(treq(Tab, {bchunk, State}), [Tab, State]);
 bchunk(Tab, Term) ->
@@ -722,11 +721,14 @@ init_chunk_match(Tab, Pat, What, N) when is_integer(N), N >= 0;
                                          N =:= default ->
     case compile_match_spec(What, Pat) of
 	{Spec, MP} ->
-	    case req(dets_server:get_pid(Tab), {match, MP, Spec, N}) of
+            Proc = dets_server:get_pid(Tab),
+	    case req(Proc, {match, MP, Spec, N}) of
 		{done, L} ->
-		    {L, #dets_cont{tab = Tab, what = What, bin = eof}};
+		    {L, #dets_cont{tab = Tab, proc = Proc, what = What,
+                                   bin = eof}};
 		{cont, State} ->
-		    chunk_match(State#dets_cont{what = What, tab = Tab});
+		    chunk_match(State#dets_cont{what = What, tab = Tab,
+                                                proc = Proc});
 		Error ->
 		    Error
 	    end;
@@ -736,34 +738,28 @@ init_chunk_match(Tab, Pat, What, N) when is_integer(N), N >= 0;
 init_chunk_match(_Tab, _Pat, _What, _) ->
     badarg.
 
-chunk_match(State) ->
-    case catch dets_server:get_pid(State#dets_cont.tab) of
-	{'EXIT', _Reason} ->
-	    badarg;
-	_Proc when State#dets_cont.bin =:= eof ->
-	    '$end_of_table';
-	Proc ->
-	    case req(Proc, {match_init, State}) of
-		{cont, {Bins, NewState}} ->
-		    MP = NewState#dets_cont.match_program,
-		    case catch do_foldl_bins(Bins, MP) of
-			{'EXIT', _} ->
-                            case ets:is_compiled_ms(MP) of
-                                true ->
-                                    Bad = dets_utils:bad_object(chunk_match, 
-                                                                Bins),
-                                    req(Proc, {corrupt, Bad});
-                                false ->
-                                    badarg
-                            end;
-                        [] ->
-                            chunk_match(NewState);
-			Terms ->
-			    {Terms, NewState}
-		    end;
-		Error ->
-		    Error
-	    end
+chunk_match(#dets_cont{proc = Proc}=State) ->
+    case req(Proc, {match_init, State}) of
+        '$end_of_table'=Reply ->
+            Reply;
+        {cont, {Bins, NewState}} ->
+            MP = NewState#dets_cont.match_program,
+            case catch do_foldl_bins(Bins, MP) of
+                {'EXIT', _} ->
+                    case ets:is_compiled_ms(MP) of
+                        true ->
+                            Bad = dets_utils:bad_object(chunk_match, Bins),
+                            req(Proc, {corrupt, Bad});
+                        false ->
+                            badarg
+                    end;
+                [] ->
+                    chunk_match(NewState);
+                Terms ->
+                    {Terms, NewState}
+            end;
+        Error ->
+            Error
     end.
 
 do_foldl_bins(Bins, true) ->
@@ -1578,13 +1574,18 @@ do_bchunk_init(Head, Tab) ->
                     L = dets_utils:all_allocated(H2),
                     C0 = #dets_cont{no_objs = default, bin = <<>>, alloc = L},
 		    BinParms = term_to_binary(Parms),
-		    {H2, {C0#dets_cont{tab = Tab, what = bchunk}, [BinParms]}}
+		    {H2, {C0#dets_cont{tab = Tab, proc = self(),what = bchunk},
+                          [BinParms]}}
 	    end;
 	{NewHead, _} = HeadError when is_record(NewHead, head) ->
 	    HeadError
     end.
 
 %% -> {NewHead, {cont(), [binary()]}} | {NewHead, Error}
+do_bchunk(Head, #dets_cont{proc = Proc}) when Proc =/= self() ->
+    {Head, badarg};
+do_bchunk(Head, #dets_cont{bin = eof}) ->
+    {Head, '$end_of_table'};
 do_bchunk(Head, State) ->
     case dets_v9:read_bchunks(Head, State#dets_cont.alloc) of
 	{error, Reason} ->
@@ -1954,6 +1955,8 @@ flookup_keys(Head, Keys) ->
     end.
 
 %% -> {NewHead, Result}
+fmatch_init(Head, #dets_cont{bin = eof}) ->
+    {Head, '$end_of_table'};
 fmatch_init(Head, C) ->
     case scan(Head, C) of
 	{scan_error, Reason} ->
-- 
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