Merge branch 'bmk/snmp/improve_error_handling_reading_config/OTP-9943' into bmk/snmp/snmp422_integration/r15

Conflicts:
	lib/snmp/test/snmp_app_test.erl

1 files changed, 80 insertions, 13 deletions

diff --git a/lib/snmp/src/misc/snmp_config.erl b/lib/snmp/src/misc/snmp_config.erl
index 6ab20e3e48..1da2c339c7 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 +2367,109 @@ 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) ->
     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)).