From 8bd83e6a805ee15c52e239e8d404e1d3e1021048 Mon Sep 17 00:00:00 2001
From: Micael Karlberg <bmk@erlang.org>
Date: Wed, 3 Apr 2019 17:53:30 +0200
Subject: [snmp|agent|test] Agent test manager start fix

The agent test manager had a bug during start that could
potentially cause deadlock, but atleast could cause test
cases to fail because of timeouts. The test manager
(actually the "packet server") used proc_lib to start the
process but it called the init_ack function before the init
was actually complete. This was only a problem for v3 cases
(where it did a bunch of further inits, including starting
the local-db process).

Also did debug/verbosity tweaking. Added a bunch of debug
(verbosity) printouts for the agent test manager "packet server"
during v3 init. Also made sure we could distinguish the
"normal" local-db from the one used by the test manager
(this is done by using a new short-name).
---
 lib/snmp/src/agent/snmpa_local_db.erl |  4 ++--
 lib/snmp/src/misc/snmp_verbosity.erl  |  3 ++-
 lib/snmp/test/snmp_test_mgr_misc.erl  | 23 +++++++++++++++++------
 3 files changed, 21 insertions(+), 9 deletions(-)

(limited to 'lib')

diff --git a/lib/snmp/src/agent/snmpa_local_db.erl b/lib/snmp/src/agent/snmpa_local_db.erl
index eb67b9cd6f..f481fe9970 100644
--- a/lib/snmp/src/agent/snmpa_local_db.erl
+++ b/lib/snmp/src/agent/snmpa_local_db.erl
@@ -147,8 +147,8 @@ init([Prio, DbDir, DbInitError, Opts]) ->
 do_init(Prio, DbDir, DbInitError, Opts) ->
     process_flag(priority, Prio),
     process_flag(trap_exit, true),
-    put(sname,ldb),
-    put(verbosity,get_opt(verbosity, Opts, ?default_verbosity)),
+    put(sname,     get_opt(sname, Opts, ldb)),
+    put(verbosity, get_opt(verbosity, Opts, ?default_verbosity)),
     ?vlog("starting",[]),
     Dets = dets_open(DbDir, DbInitError, Opts),
     Ets  = ets:new(?ETS_TAB, [set, protected]),
diff --git a/lib/snmp/src/misc/snmp_verbosity.erl b/lib/snmp/src/misc/snmp_verbosity.erl
index edfb52a474..bca4bad283 100644
--- a/lib/snmp/src/misc/snmp_verbosity.erl
+++ b/lib/snmp/src/misc/snmp_verbosity.erl
@@ -155,7 +155,8 @@ image_of_sname(mgr)       -> "MGR";
 image_of_sname(mgr_misc)  -> "MGR_MISC";
 
 image_of_sname(undefined) -> "";
-image_of_sname(V)         -> lists:flatten(io_lib:format("~p",[V])).
+image_of_sname(N) when is_list(N) -> N; % Used in testing
+image_of_sname(N)         -> lists:flatten(io_lib:format("~p", [N])).
 
 
 validate(info)  -> info;
diff --git a/lib/snmp/test/snmp_test_mgr_misc.erl b/lib/snmp/test/snmp_test_mgr_misc.erl
index 9e76452345..89d6f93a88 100644
--- a/lib/snmp/test/snmp_test_mgr_misc.erl
+++ b/lib/snmp/test/snmp_test_mgr_misc.erl
@@ -38,6 +38,7 @@
 
 -define(SNMP_USE_V3, true).
 -include_lib("snmp/include/snmp_types.hrl").
+-include_lib("snmp/src/misc/snmp_verbosity.hrl").
 
 
 %%----------------------------------------------------------------------
@@ -101,11 +102,11 @@ init_packet(
   DbgOptions, IpFamily) ->
     put(sname, mgr_misc),
     init_debug(DbgOptions),
-    {ok, UdpId} =
-	gen_udp:open(TrapUdp, [{recbuf,BufSz}, {reuseaddr, true}, IpFamily]),
+    UdpOpts     = [{recbuf,BufSz}, {reuseaddr, true}, IpFamily],
+    {ok, UdpId} = gen_udp:open(TrapUdp, UdpOpts),
     put(msg_id, 1),
-    proc_lib:init_ack(Parent, self()),
     init_usm(Version, Dir),
+    proc_lib:init_ack(Parent, self()),
     packet_loop(SnmpMgr, UdpId, AgentIp, UdpPort, VsnHdr, Version, []).
 
 init_debug(Dbg) when is_atom(Dbg) ->
@@ -598,15 +599,25 @@ set_pdu(Msg, RePdu) ->
 
 
 init_usm('version-3', Dir) ->
+    ?vlog("init_usm -> create (and init) fake \"agent\" table", []),
     ets:new(snmp_agent_table, [set, public, named_table]),
     ets:insert(snmp_agent_table, {agent_mib_storage, persistent}),
-    snmpa_local_db:start_link(normal, Dir, [{verbosity,trace}]),
+    ?vlog("init_usm -> try start fake local-db", []),
+    {ok, _} = snmpa_local_db:start_link(normal, Dir,
+                                        [{sname,     "MGR-LOCAL-DB"},
+                                         {verbosity, trace}]),
     NameDb = snmpa_agent:db(snmpEngineID),
+    ?vlog("init_usm -> try set manager engine-id", []),
     R = snmp_generic:variable_set(NameDb, "mgrEngine"),
-    io:format("~w:init_usm -> engine-id set result: ~p~n", [?MODULE,R]),
+    snmp_verbosity:print(info, info, "init_usm -> engine-id set result: ~p", [R]),
+    ?vlog("init_usm -> try set engine boots (framework-mib)", []),
     snmp_framework_mib:set_engine_boots(1),
+    ?vlog("init_usm -> try set engine time (framework-mib)", []),
     snmp_framework_mib:set_engine_time(1),
-    snmp_user_based_sm_mib:reconfigure(Dir);
+    ?vlog("init_usm -> try usm (mib) reconfigure", []),
+    snmp_user_based_sm_mib:reconfigure(Dir),
+    ?vlog("init_usm -> done", []),
+    ok;
 init_usm(_Vsn, _Dir) ->
     ok.
 
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