Exec module changes/fixes.

- Give Dir::monitor() a param for the polling interval, so different
  dirs can be monitored at different frequencies.

- Fix race in Exec::run() when reading extra output files produced by
  a process -- it was possible for Exec::run() to return before all
  extra output files had been fully read.

- Add test cases.

scripts/base/utils/exec.bro

@@ -14,6 +14,8 @@ export {
 		## If additional files are required to be read in as part of the output
 		## of the command they can be defined here.
 		read_files:  set[string] &optional;
+		# The unique id for tracking executors.
+		uid: string &default=unique_id("");
 	};
 
 	type Result: record {
@@ -44,14 +46,11 @@ export {
 	const tmp_dir = "/tmp" &redef;
 }
 
-redef record Command += {
-	# The unique id for tracking executors.
-	uid: string &optional;
-};
+# Indexed by command uid.
+global results: table[string] of Result;
+global pending_commands: set[string];
+global pending_files: table[string] of set[string];
 
-global results: table[string] of Result = table();
-global finished_commands: set[string];
-global currently_tracked_files: set[string] = set();
 type OneLine: record {
 	s: string;
 	is_stderr: bool;
@@ -96,39 +95,63 @@ event Exec::file_line(description: Input::EventDescription, tpe: Input::Event, s
 		result$files[track_file][|result$files[track_file]|] = s;
 	}
 
+event Input::end_of_data(name: string, source:string)
+	{
+	local parts = split1(name, /_/);
+	name = parts[1];
+
+	if ( name !in pending_commands || |parts| < 2 )
+		return;
+
+	local track_file = parts[2];
+
+	Input::remove(name);
+
+	if ( name !in pending_files )
+		delete pending_commands[name];
+	else
+		{
+		delete pending_files[name][track_file];
+		if ( |pending_files[name]| == 0 )
+			delete pending_commands[name];
+		system(fmt("rm \"%s\"", str_shell_escape(track_file)));
+		}
+	}
+
 event InputRaw::process_finished(name: string, source:string, exit_code:count, signal_exit:bool)
 	{
+	if ( name !in pending_commands )
+		return;
+
+	Input::remove(name);
 	results[name]$exit_code = exit_code;
 	results[name]$signal_exit = signal_exit;
 
-	Input::remove(name);
-	# Indicate to the "when" async watcher that this command is done.
-	add finished_commands[name];
-	}
-
-event Exec::start_watching_file(uid: string, read_file: string)
-	{
-	Input::add_event([$source=fmt("%s", read_file),
-	                  $name=fmt("%s_%s", uid, read_file),
-	                  $reader=Input::READER_RAW,
-	                  $mode=Input::STREAM,
-	                  $want_record=F,
-	                  $fields=FileLine,
-	                  $ev=Exec::file_line]);
+	if ( name !in pending_files || |pending_files[name]| == 0 )
+		# No extra files to read, command is done.
+		delete pending_commands[name];
+	else
+		for ( read_file in pending_files[name] )
+			Input::add_event([$source=fmt("%s", read_file),
+			                  $name=fmt("%s_%s", name, read_file),
+			                  $reader=Input::READER_RAW,
+			                  $want_record=F,
+			                  $fields=FileLine,
+			                  $ev=Exec::file_line]);
 	}
 
 function run(cmd: Command): Result
 	{
-	cmd$uid = unique_id("");
+	add pending_commands[cmd$uid];
 	results[cmd$uid] = [];
 
 	if ( cmd?$read_files )
 		{
 		for ( read_file in cmd$read_files )
 			{
-			add currently_tracked_files[read_file];
-			system(fmt("touch \"%s\" 2>/dev/null", str_shell_escape(read_file)));
-			schedule 1msec { Exec::start_watching_file(cmd$uid, read_file) };
+			if ( cmd$uid !in pending_files )
+				pending_files[cmd$uid] = set();
+			add pending_files[cmd$uid][read_file];
 			}
 		}
 
@@ -144,9 +167,8 @@ function run(cmd: Command): Result
 	                  $want_record=F,
 	                  $config=config_strings]);
 
-	return when ( cmd$uid in finished_commands )
+	return when ( cmd$uid !in pending_commands )
 		{
-		delete finished_commands[cmd$uid];
 		local result = results[cmd$uid];
 		delete results[cmd$uid];
 		return result;
@@ -155,9 +177,8 @@ function run(cmd: Command): Result
 
 event bro_done()
 	{
-	# We are punting here and just deleting any files that haven't been processed yet.
-	for ( fname in currently_tracked_files )
-		{
-		system(fmt("rm \"%s\"", str_shell_escape(fname)));
-		}
+	# We are punting here and just deleting any unprocessed files.
+	for ( uid in pending_files )
+		for ( fname in pending_files[uid] )
+			system(fmt("rm \"%s\"", str_shell_escape(fname)));
 	}