[snmp/agent] Some minor improvements to the error messages

OTP-9943

3 files changed, 100 insertions, 14 deletions

diff --git a/lib/snmp/src/agent/snmp_standard_mib.erl b/lib/snmp/src/agent/snmp_standard_mib.erl
index 7c78e03b3b..ca93546923 100644
--- a/lib/snmp/src/agent/snmp_standard_mib.erl
+++ b/lib/snmp/src/agent/snmp_standard_mib.erl
@@ -156,7 +156,7 @@ read_standard(Dir) ->
     Gen        = fun(D, Reason) -> 
 			 throw({error, {failed_reading_config_file, 
 					D, FileName, 
-					file:list_dir(Dir), Reason}})
+					list_dir(Dir), Reason}})
 		 end,
     Filter     = fun(Standard) -> sort_standard(Standard) end,
     Check      = fun(Entry) -> check_standard(Entry) end,
@@ -164,6 +164,14 @@ read_standard(Dir) ->
 	snmp_conf:read_files(Dir, [{Gen, Filter, Check, FileName}]), 
     Standard.
 
+list_dir(Dir) ->
+    case file:list_dir(Dir) of
+	{ok, Files} ->
+	    Files;
+	Error ->
+	    Error
+    end.
+
 
 %%-----------------------------------------------------------------
 %% Make sure that each mandatory standard attribute is present, and
diff --git a/lib/snmp/src/app/snmp.appup.src b/lib/snmp/src/app/snmp.appup.src
index a0c065dba3..60877c547e 100644
--- a/lib/snmp/src/app/snmp.appup.src
+++ b/lib/snmp/src/app/snmp.appup.src
@@ -24,6 +24,7 @@
  [
   {"4.21.7",
    [
+    {load_module, snmp_config, soft_purge, soft_purge, []}, 
     {load_module, snmp_conf, soft_purge, soft_purge, []}, 
     {load_module, snmp_community_mib, soft_purge, soft_purge, [snmp_conf]}, 
     {load_module, snmp_framework_mib, soft_purge, soft_purge, [snmp_conf]}, 
@@ -149,6 +150,7 @@
  [
   {"4.21.7",
    [
+    {load_module, snmp_config, soft_purge, soft_purge, []}, 
     {load_module, snmp_conf, soft_purge, soft_purge, []}, 
     {load_module, snmp_community_mib, soft_purge, soft_purge, [snmp_conf]}, 
     {load_module, snmp_framework_mib, soft_purge, soft_purge, [snmp_conf]}, 
diff --git a/lib/snmp/src/misc/snmp_config.erl b/lib/snmp/src/misc/snmp_config.erl
index 6ab20e3e48..8bf0ea945b 100644
--- a/lib/snmp/src/misc/snmp_config.erl
+++ b/lib/snmp/src/misc/snmp_config.erl
@@ -90,6 +90,17 @@
 	]).
 
 
+-export_type([void/0, 
+	      verify_config_entry_function/0, 
+	      verify_config_function/0, 
+	      write_config_function/0]).
+
+
+%%----------------------------------------------------------------------
+
+-type void() :: term(). % Any value - ignored
+
+
 %%----------------------------------------------------------------------
 %% Handy SNMP configuration
 %%----------------------------------------------------------------------
@@ -2356,53 +2367,118 @@ write_sys_config_file_manager_atl_opt(Fid, {seqno, SeqNo}) ->
 
 
 header() ->
-    {Y,Mo,D} = date(),
-    {H,Mi,S} = time(),
+    {Y, Mo, D} = date(),
+    {H, Mi, S} = time(),
     io_lib:format("%% This file was generated by "
-		  "snmp_config (version-~s) ~w-~2.2.0w-~2.2.0w "
+		  "~w (version-~s) ~w-~2.2.0w-~2.2.0w "
 		  "~2.2.0w:~2.2.0w:~2.2.0w\n",
-		  [?version,Y,Mo,D,H,Mi,S]).
+		  [?MODULE, ?version, Y, Mo, D, H, Mi, S]).
+
 
+%% *If* these functions are successfull, they successfully return anything
+%% (which is ignored), but they fail with either a throw or an exit or 
+%% something similar.
+
+%% Verification of one config entry read from a file
+-type(verify_config_entry_function() :: 
+      fun((Entry :: term()) -> ok | {error, Reason :: term()})).
+
+%% Verification of config to be written
+-type(verify_config_function() :: 
+      fun(() -> void())).
+
+%% Write config to file (as defined by Fd)
+-type(write_config_function() :: 
+      fun((Fd :: file:io_device()) -> void())).
+
+-spec write_config_file(Dir :: string(), 
+			FileName :: string(), 
+			Verify :: verify_config_function(), 
+			Write :: write_config_function()) ->
+    ok | {error, Reason :: term()}.
 
 write_config_file(Dir, FileName, Verify, Write) 
   when (is_list(Dir) andalso 
 	is_list(FileName) andalso 
 	is_function(Verify) andalso 
 	is_function(Write)) ->
-    (catch do_write_config_file(Dir, FileName, Verify, Write)).
+    try
+	begin
+	    do_write_config_file(Dir, FileName, Verify, Write)
+	end
+    catch
+	throw:Error ->
+	    Error;
+	  T:E ->
+	    {error, {failed_write, Dir, FileName, T, E}}
+    end.
+
 
 do_write_config_file(Dir, FileName, Verify, Write) ->
+    io:format("do_write_config_file -> entry with"
+	      "~n   Dir:           ~p"
+	      "~n   FileName:      ~p"
+	      "~nwhen"
+	      "~n   FileInfo(Dir): ~p"
+	      "~n   FileList(Dir): ~p"
+	      "~n", [Dir, FileName, 
+		     file:read_file_info(filename:join(Dir, FileName)), 
+		     file:list_dir(Dir)]),
     Verify(),
     case file:open(filename:join(Dir, FileName), [write]) of
 	{ok, Fd} ->
-	    (catch Write(Fd)),
-	    file:close(Fd),
-	    ok;
+	    file_write_and_close(Write, Fd, Dir, FileName);
 	Error ->
 	    Error
     end.
 
-
 append_config_file(Dir, FileName, Verify, Write) 
   when (is_list(Dir) andalso 
 	is_list(FileName) andalso 
 	is_function(Verify) andalso 
 	is_function(Write)) ->
-    (catch do_append_config_file(Dir, FileName, Verify, Write)).
+    try
+	begin
+	    do_append_config_file(Dir, FileName, Verify, Write)
+	end
+    catch
+	throw:Error ->
+	    Error;
+	  T:E ->
+	    {error, {failed_append, Dir, FileName, T, E}}
+    end.
 
 do_append_config_file(Dir, FileName, Verify, Write) ->
     Verify(),
     case file:open(filename:join(Dir, FileName), [read, write]) of
 	{ok, Fd} ->
 	    file:position(Fd, eof),
-	    (catch Write(Fd)),
-	    file:close(Fd),
-	    ok;
+	    file_write_and_close(Write, Fd, Dir, FileName);
 	Error ->
 	    Error
     end.
 
 
+file_write_and_close(Write, Fd, Dir, FileName) ->
+    ok = Write(Fd),
+    case file:sync(Fd) of
+	ok ->
+	    case file:close(Fd) of
+		ok ->
+		    ok;
+		{error, Reason} ->
+		    {error, {failed_closing, Dir, FileName, Reason}}
+	    end;
+	{error, Reason} ->
+	    {error, {failed_syncing, Dir, FileName, Reason}}
+    end.
+
+
+-spec read_config_file(Dir :: string(), 
+		       FileName :: string(), 
+		       Verify :: verify_config_entry_function()) ->
+    {ok, Config :: list()} | {error, Reason :: term()}.
+
 read_config_file(Dir, FileName, Verify) 
   when is_list(Dir) andalso is_list(FileName) andalso is_function(Verify) ->
     (catch do_read_config_file(Dir, FileName, Verify)).