[snmp/agent] Simultaneous snmpa:backup/1,2 calls interfere

Simultaneous snmpa#backup">snmpa:backup/1,2 calls interfere.
The master agent did not check if a backup was already in
progress when a backup request was accepted

OTP-9884

1 files changed, 11 insertions, 3 deletions

diff --git a/lib/snmp/src/agent/snmpa_mib.erl b/lib/snmp/src/agent/snmpa_mib.erl
index ce90db18b3..574467d38f 100644
--- a/lib/snmp/src/agent/snmpa_mib.erl
+++ b/lib/snmp/src/agent/snmpa_mib.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2010. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2012. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -552,8 +552,12 @@ handle_call({dump, File}, _From, #state{data = Data} = State) ->
     Reply = snmpa_mib_data:dump(Data, File),
     {reply, Reply, State};
     
-handle_call({backup, BackupDir}, From, #state{data = Data} = State) ->
-    ?vlog("backup to ~s",[BackupDir]),
+%% This check (that there is no backup already in progress) is also 
+%% done in the master agent process, but just in case a user issues 
+%% a backup call to this process directly, we add a similar check here. 
+handle_call({backup, BackupDir}, From, 
+	    #state{backup = undefined, data = Data} = State) ->
+    ?vlog("backup to ~s", [BackupDir]),
     Pid = self(),
     V   = get(verbosity),
     case file:read_file_info(BackupDir) of
@@ -576,6 +580,10 @@ handle_call({backup, BackupDir}, From, #state{data = Data} = State) ->
 	    {reply, Error, State}
     end;
     
+handle_call({backup, _BackupDir}, From, #state{backup = Backup} = S) ->
+    ?vinfo("backup already in progress: ~p", [Backup]),
+    {reply, {error, backup_in_progress}, S};
+
 handle_call(stop, _From, State) ->
     ?vlog("stop",[]),    
     {stop, normal, ok, State};