[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, 8 insertions, 3 deletions

diff --git a/lib/snmp/src/agent/snmpa_agent.erl b/lib/snmp/src/agent/snmpa_agent.erl
index 00fe9be098..e3178aacc6 100644
--- a/lib/snmp/src/agent/snmpa_agent.erl
+++ b/lib/snmp/src/agent/snmpa_agent.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
@@ -1190,7 +1190,8 @@ handle_call(info, _From, S) ->
 handle_call(get_net_if, _From, S) ->
     {reply, get(net_if), S};
 
-handle_call({backup, BackupDir}, From, S) ->
+%% Only accept a backup request if there is none already in progress
+handle_call({backup, BackupDir}, From, #state{backup = undefined} = S) ->
     ?vlog("backup: ~p", [BackupDir]),
     Pid = self(),
     V   = get(verbosity),
@@ -1207,7 +1208,11 @@ handle_call({backup, BackupDir}, From, S) ->
 	  end),
     ?vtrace("backup server: ~p", [BackupServer]),
     {noreply, S#state{backup = {BackupServer, From}}};
-    
+
+handle_call({backup, _BackupDir}, From, #state{backup = Backup} = S) ->
+    ?vinfo("backup already in progress: ~p", [Backup]),
+    {reply, {error, backup_in_progress}, S};
+
 handle_call(dump_mibs, _From, S) ->
     Reply = snmpa_mib:dump(get(mibserver)),
     {reply, Reply, S};