CLIte/clite/shell.js

clite.commands.data = function() {
// insert commands below this line

clite.commands.load('sh',function(args,env,io) {
	var stdio = io.include('stdio');
	var stdlib = io.include('stdlib');
	var term = io.include('term');
	var clite = io.include('clite');

	var has_exited = false;
	let builtins = ['clear','cd','pwd','echo','which','type','whoami','alias','export','true','false','exit'];
	let builtins_func = [builtin_clear,builtin_cd,builtin_pwd,builtin_echo,builtin_which,builtin_type,builtin_whoami,builtin_alias,builtin_export,builtin_true,builtin_false,builtin_exit];
	let history_data = [];
	let history_current = '';
	let history_index = 0;
	let parser_files = [];
	let parser_callback = null;
	let parser_lines = [];
	let parser_script = null;
	let exec_callback = null;
	let exec_cmds = [];
	let exec_active = null;
	let exec_bufferout = null;
	let exec_bufferin = null;
	let exec_skipto = null;
	let exec_closout = false;
	let exec_closin = false;
	let exec_closerr = false;
	let exec_last = 0;
	let exec_io = {};
	let exec_conditionals = [];
	let exec_loops = [];

	function builtin_clear(args,io) {
		term.clear();
		return 0;
	}
	function builtin_cd(args,io) {
		var dir = env.HOME;
		if (args.length > 1)
			dir = clite.resolvePath(args[1]);
		var fd = stdio.open(dir,stdio.flags.O_SEARCH|stdio.flags.O_DIRECTORY);
		if (!fd) {
			stdio.fprintf(io.stderr,'invalid directory: %s\n',dir);
			return 1;
		}
		stdio.close(fd);
		env.PWD = dir;
		return 0;
	}
	function builtin_pwd(args,io) {
		stdio.fprintf(io.stdout,'%s\n',env.PWD);
		return 0;
	}
	function builtin_echo(args,io) {
		args.shift();
		var txt = args.join(' ')+'\n';
		stdio.write(io.stdout,txt);
		return 0;
	}
	function builtin_which(args,io) {
		if (args.length <2)
			return 1;
		if (builtins.indexOf(args[1]) > -1) {
			return 1;
		}else{
			var path = resolvePATH(args[1]);
			if (!path)
				return 1;
			stdio.fprintf(io.stdout,'%s is %s\n',args[1],path);
		}
		return 0;
	}
	function builtin_type(args,io) {
		if (args.length <2)
			return 1;
		if (builtins.indexOf(args[1]) > -1) {
			stdio.fprintf(io.stdout,'%s is a shell builtin\n',args[1]);
		}else{
			var path = resolvePATH(args[1]);
			if (!path)
				return 1;
			stdio.fprintf(io.stdout,'%s is %s\n',args[1],path);
		}
		return 0;
	}
	function builtin_whoami(args,io) {
		stdio.fprintf(io.stdout,'%s\n',env.USER);
		return 0;
	}
	function builtin_alias(args,io) {
		stdio.fprintf(io.stdout,'unimplemented\n');
		return 0;
	}
	function builtin_export(args,io) {
		if (args.length == 1) {
			Object.keys(env).forEach(function(key) {
				stdio.fprintf(io.stdout,'%s=%s\n',key,env[key]);
			});
			return 0;
		}
		var parts = args[1].split('=');
		if (parts.length != 2)
			return 0;
		env[parts[0]] = parts[1];
		return 0;
	}
	function builtin_true(args,io) {
		return 0;
	}
	function builtin_false(args,io) {
		return 1;
	}
	function builtin_exit(args,io) {
		var ev = 0;
		if (args.length > 1)
			ev = parseInt(args[1]);
		doShellExit(ev);
		return 0;
	}

	function history_load() {
		let path = clite.resolvePath('~/.shhistory');
		let fd = stdio.open(path,stdio.flags.O_RDONLY|stdio.flags.O_SYNC);
		if (!fd)
			return;
		var e;
		while ((e = stdio.readLine(fd)) != null) {
			history_add(e);
		}
		stdio.close(fd);
	}
	function history_save() {
		let path = clite.resolvePath('~/.shhistory');
		let fd = stdio.open(path,stdio.flags.O_WRONLY|stdio.flags.O_TRUNC|stdio.flags.O_CREAT|stdio.flags.O_SYNC);
		if (!fd)
			return;
		history_data.forEach(function(l) {
			stdio.write(fd,l+'\n');
		});
		stdio.close(fd);
	}
	function history_add(txt) {
		if (txt.length < 1)
			return;
		if (history_data.length > 0 && history_data[history_data.length-1] == txt)
			return;
		history_data.push(txt);
		history_index = history_data.length;
	}
	function history_up() {
		if (history_index < 1)
			return null;
		history_index--;
		return history_getCurrent();
	}
	function history_down() {
		if (history_index >= history_data.length)
			return null;
		history_index++;
		return history_getCurrent();
	}
	function history_setCurrent(txt) {
		history_current = txt;
	}
	function history_getCurrent() {
		if (history_index >= history_data.length)
			return history_current;
		return history_data[history_index];
	}
	function history_resetCurrent() {
		history_current = '';
		history_index = history_data.length;
	}
	function history_clear() {
		history_data = [];
		history_current = '';
		history_index = 0;
	}

	function parser_queue(file) {
		parser_files.push(file);
	}
	function parser_parseFile(f) {
		var fn = clite.resolvePath(f);
		if (fn == null) {
			parser_run();
			return;
		}
		var st = stdio.stat(fn);
		if (st == null || st.type != stdio.types.FT_SCRIPT) {
			parser_run();
			return;
		}
		var fd = stdio.open(fn,stdio.flags.O_RDONLY,parser_prepFile);
		if (!fd)
			parser_run();
	}
	function parser_prepFile(fd) {
		var data = stdio.readAll(fd);
		if (fd != io.stdin)
			stdio.close(fd);
		if (!data) {
			parser_run();
			return;
		}
		parser_script = '';
		parser_lines = data.split('\n');
		if (parser_lines.length < 1) {
			parser_run();
			return;
		}
		parser_parseLine();
	}
	function parser_parseLine() {
		var l = parser_lines.shift();
		if (l == null) {
			parser_exec();
			return;
		}
		if (l[0] != '#')
			parser_script += l+'; ';
		parser_parseLine();
	}
	function parser_exec() {
		exec_setCommand(parser_script);
		exec_run(parser_run);
	}
	function parser_exit() {
		if (typeof parser_callback !== 'function')
			return;
		try{
			parser_callback();
		} catch(err) {
			stdio.write(io.stderr,'Shell: internal error in parser\n');
			io.exit(1);
			return;
		}
	}
	function parser_run(cb) {
		if (typeof cb === 'function')
			parser_callback = cb;
		var f = parser_files.shift();
		if (!f) {
			parser_exit();
			return;
		}
		parser_parseFile(f);
	}
	function parser_stdin() {
		parser_callback = function() {
			io.exit(0);
		}
		parser_prepFile(io.stdin);
	}

	function exec_doCommand(cmd) {
		exec_active = cmd;
		if ((cmd.onlastsuccess && exec_last != 0) || (cmd.onlastfail && exec_last == 0)) {
			exec_run();
			return;
		}
		switch (cmd.args[0]) {
		case 'if':
			exec_conditionals.push(cmd);
			exec_run();
			return;
			break;
		case 'then':
			if (exec_last == 0) {
				exec_conditionals[exec_conditionals.length-1].conditional = true;
			}else{
				exec_conditionals[exec_conditionals.length-1].conditional = false;
				exec_skipto = 'else';
			}
			exec_run();
			return;
			break;
		case 'else':
			if (exec_conditionals[exec_conditionals.length-1].conditional != false) {
				exec_skipto = 'fi';
			}
			exec_run();
			return;
			break;
		case 'fi':
			exec_conditionals.pop();
			exec_run();
			return;
			break;
		case 'while':
		case 'do':
		case 'done':
			exec_run();
			return;
			break;
		default:;
		}
		var usebi = false;
		var usebo = false;
		if (cmd.stdin != '&0') {
			switch (cmd.stdin) {
			case '|':
				exec_stdin_setOut();
				usebi = true;
				break;
			case null:
				exec_stdin_setNull();
				break;
			default:
				exec_stdin_setFile(cmd.stdin);
				break;
			}
		}else{
			if (exec_closin) {
				stdio.close(exec_io.stdin);
				exec_closin = false;
			}
			exec_io.stdin = io.stdin;
		}
		if (cmd.stdout != '&1') {
			switch (cmd.stdout) {
			case '|':
				exec_stdout_setBuffered();
				usebo = true;
				break;
			case null:
				exec_stdout_setNull();
				break;
			default:
				exec_stdout_setFile(cmd.stdout);
				break;
			}
		}else{
			if (exec_closout) {
				stdio.close(exec_io.stdout);
				exec_closout = false;
			}
			exec_io.stdout = io.stdout;
		}
		if (cmd.stderr != '&2') {
			switch (cmd.stderr) {
			case '&1':
				exec_stderr_setOut();
				break;
			case null:
				exec_stderr_setNull();
				break;
			default:
				exec_stderr_setFile(cmd.stderr);
				break;
			}
		}else{
			if (exec_closerr) {
				stdio.close(exec_io.stderr);
				exec_closerr = false;
			}
			exec_io.stderr = io.stderr;
		}
		if (exec_io.stdin == null) {
			stdio.write(io.stderr,'could not open standard input for reading\n');
			exec_setLast(1);
			exec_run();
			return;
		}
		if (exec_io.stdout == null) {
			stdio.write(io.stderr,'could not open standard output for writing\n');
			exec_setLast(1);
			exec_run();
			return;
		}
		if (exec_io.stderr == null) {
			stdio.write(io.stderr,'could not open standard error for writing\n');
			exec_setLast(1);
			exec_run();
			return;
		}
		if (builtins.indexOf(cmd.args[0]) > -1) {
			exec_io.exit = io.exit;
			let fn = builtins.indexOf(cmd.args[0]);

			let r = builtins_func[fn](cmd.args,exec_io);

			exec_setLast(r);
			exec_run();
			return;
		}

		if (!cmd.path) {
			stdio.fprintf(io.stderr,'Shell: unknown command: %s\n',cmd.args[0]);
			exec_setLast(1);
			exec_run();
			return;
		}
		var pid = stdlib.fork(env,exec_io,exec_doExec);
		if (pid == 0) {
			stdio.write(io.stderr,'Shell: internal error\n');
			exec_setLast(1);
			exec_run();
			return;
		}

		stdlib.waitpid(pid,function(pid,ev) {
			exec_setLast(ev);
			exec_run();
		});
	}
	function exec_doExec(env,io) {
		var r = stdlib.exec(exec_active.path,exec_active.args,env,io);
		if (r > 0)
			return;

		if (r == -1) {
			stdlib.fprintf(io.stderr,'Shell: unknown command: %s\n',exec_active.args[0]);
			io.exit(-1);
			return;
		}

		if (r == -2) {
			stdio.fprintf(io.stderr,'Shell: error in command: %s\n',exec_active.args[0]);
			io.exit(-1);
			return;
		}

		if (r == -3 || r == -4) {
			stdio.fprintf(io.stderr,'Shell: not an executable file: %s\n',exec_active.args[0]);
			io.exit(-3);
			return;
		}

		if (r == -5) {
			stdio.fprintf(io.stderr,'Shell: invalid parser for file: %s\n',exec_active.args[0]);
			io.exit(-3);
			return;
		}

		if (r == -6) {
			stdio.fprintf(io.stderr,'Shell: no valid parser for file: %s\n',exec_active.args[0]);
			io.exit(-3);
			return;
		}

		if (r == -7 || r == -8) {
			stdio.fprintf(io.stderr,'Shell: failed to set uid/gid for: %s\n',exec_active.args[0]);
			io.exit(-3);
			return;
		}

		if (r<0) {
			stdio.fprintf(io.stderr,'Shell: could not exec file: %s\n',exec_active.args[0]);
			io.exit(-3);
		}
	}
	function exec_setLast(v) {
		exec_last = parseInt(v);
		env['?'] = exec_last.toString();
	}
	function exec_setCommand(txt) {
		var args = clite.strToArgs(txt);
		if (args.length < 1)
			return;
		args.forEach(function(val,i) {
			args[i] = preprocess(val);
		});
		var cmd = {
			args:[],
			path:null,
			stdin:'&0',
			stdout:'&1',
			stderr:'&2',
			onlastsuccess:false,
			onlastfail:false,
			conditional:false
		};
		var c = structuredClone(cmd);
		exec_cmds = [];
		var fault = false;
		var conds = [];
		var loops = [];
		for (var i=0; i<args.length; i++) {
			if (args[i] == ';') {
				if (c.args.length > 0) {
					exec_cmds.push(c);
					c = structuredClone(cmd);
				}
				continue;
			}
			if (args[i] == 'if') {
				if (c.args.length > 0) {
					exec_cmds.push(c);
					c = structuredClone(cmd);
				}
				c.args.push(args[i]);
				exec_cmds.push(c);
				conds.push(c);
				c = structuredClone(cmd);
				continue;
			}
			if (args[i] == 'then') {
				if (c.args.length > 0) {
					exec_cmds.push(c);
					c = structuredClone(cmd);
				}
				c.args.push(args[i]);
				exec_cmds.push(c);
				if (conds.length < 1) {
					fault = true;
				}else{
					conds[conds.length-1].args.push(c);
				}
				c = structuredClone(cmd);
				continue;
			}
			if (args[i] == 'else') {
				if (c.args.length > 0) {
					exec_cmds.push(c);
					c = structuredClone(cmd);
				}
				c.args.push(args[i]);
				exec_cmds.push(c);
				if (conds.length < 1) {
					fault = true;
				}else{
					conds[conds.length-1].args.push(c);
				}
				c = structuredClone(cmd);
				continue;
			}
			if (args[i] == 'fi') {
				if (c.args.length > 0) {
					exec_cmds.push(c);
					c = structuredClone(cmd);
				}
				c.args.push(args[i]);
				exec_cmds.push(c);
				if (conds.length < 1) {
					fault = true;
				}else{
					conds[conds.length-1].args.push(c);
					conds.pop();
				}
				c = structuredClone(cmd);
				continue;
			}
			if (args[i] == 'while') {
				if (c.args.length > 0) {
					exec_cmds.push(c);
					c = structuredClone(cmd);
				}
				c.args.push(args[i]);
				exec_cmds.push(c);
				loops.push(c);
				c = structuredClone(cmd);
				continue;
			}
			if (args[i] == 'do') {
				if (c.args.length > 0) {
					exec_cmds.push(c);
					c = structuredClone(cmd);
				}
				c.args.push(args[i]);
				exec_cmds.push(c);
				if (loops.length < 1) {
					fault = true;
				}else{
					loops[loops.length-1].args.push(c);
				}
				c = structuredClone(cmd);
				continue;
			}
			if (args[i] == 'done') {
				if (c.args.length > 0) {
					exec_cmds.push(c);
					c = structuredClone(cmd);
				}
				c.args.push(args[i]);
				exec_cmds.push(c);
				if (loops.length < 1) {
					fault = true;
				}else{
					loops[loops.length-1].args.push(c);
					loops.pop();
				}
				c = structuredClone(cmd);
				continue;
			}
			if (args[i] == '|') {
				c.stdout = '|';
				exec_cmds.push(c);
				c = structuredClone(cmd);
				c.stdin = '|';
				continue;
			}
			if (args[i] == '||') {
				exec_cmds.push(c);
				c = structuredClone(cmd);
				c.onlastfail = true;
				continue;
			}
			if (args[i] == '&&') {
				exec_cmds.push(c);
				c = structuredClone(cmd);
				c.onlastsuccess = true;
				continue;
			}
			if (args[i] == '>') {
				i++;
				c.stdout = clite.resolvePath(args[i]);
				if (c.stdout == '/dev/null')
					c.stdout = null;
				continue;
			}
			if (args[i] == '2>&1') {
				c.stderr = '&1';
				continue;
			}
			if (args[i] == '>>') {
				i++;
				c.stdout = clite.resolvePath(args[i]);
				if (c.stdout == '/dev/null') {
					c.stdout = null;
				}else{
					c.stdout = '+'+c.stdout;
				}
				continue;
			}
			if (args[i] == '<') {
				i++;
				c.stdin = clite.resolvePath(args[i]);
				if (c.stdin == '/dev/null')
					c.stdin = null;
				continue;
			}
			c.args.push(args[i]);
		}
		if (conds.length > 0)
			fault = true;
		if (loops.length > 0)
			fault = true;
		if (c.args.length > 0)
			exec_cmds.push(c);
		exec_cmds.forEach(function(c,i) {
			if (c.args.length < 1) {
				fault = true;
				return;
			}
			c.args[0] = c.args[0].trim();
			c.path = resolvePATH(c.args[0]);
		});
		if (fault) {
			stdio.write(io.stderr,'Shell: unable to parse command\n');
			exec_exit();
			return;
		}
		exec_io.pid = io.pid;
		exec_io.stdin = io.stdin;
		exec_io.stdout = io.stdout;
		exec_io.stderr = io.stderr;
		exec_io.exit = null;		// filled in by fork()
		exec_io.include = null;		// filled in by fork()
		exec_last = 0;
	}
	function exec_stdin_setFile(path) {
		if (exec_closin) {
			stdio.close(exec_io.stdin);
			exec_closin = false;
		}
		exec_io.stdin = stdio.open(path,stdio.flags.O_RDONLY);
		exec_closin = true;
	}
	function exec_stdin_setNull() {
		if (exec_closin) {
			stdio.close(exec_io.stdin);
			exec_closin = false;
		}
		exec_io.stdin = stdio.open('/dev/null',stdio.flags.O_RDONLY);
		exec_closin = true;
	}
	function exec_stdin_setOut() {
		if (exec_closin) {
			stdio.close(exec_io.stdin);
			exec_closin = false;
		}
		if (exec_bufferout) {
			exec_io.stdout = null;
			exec_closout = false;
			exec_bufferin = exec_bufferout;
			exec_bufferout = null;
			exec_io.stdin = exec_bufferin;
			stdio.seek(exec_io.stdin,0);
			exec_closin = true;
		}else{
			exec_stdin_setNull();
		}
	}
	function exec_stdout_setBuffered() {
		if (exec_closout) {
			stdio.close(exec_io.stdout);
			exec_closout = false;
			if (exec_bufferout)
				exec_bufferout = null;
		}
		exec_bufferout = stdio.mkstemp('/tmp/shell-XXXXXX');
		exec_io.stdout = exec_bufferout;
		exec_closout = false;
	}
	function exec_stdout_setFile(path) {
		if (exec_closout) {
			stdio.close(exec_io.stdout);
			exec_closout = false;
		}
		var flags = stdio.flags.O_WRONLY|stdio.flags.O_CREAT|stdio.flags.O_SYNC;
		var p = path;
		if (path[0] == '+') {
			flags |= stdio.flags.O_APPEND;
			p = path.substring(1);
		}else{
			flags |= stdio.flags.O_TRUNC;
		}
		exec_io.stdout = stdio.open(p,flags);
		exec_closout = true;
	}
	function exec_stdout_setNull() {
		if (exec_closout) {
			stdio.close(exec_io.stdout);
			exec_closout = false;
		}
		exec_io.stdout = stdio.open('/dev/null',stdio.flags.O_WRONLY);
		exec_closout = true;
	}
	function exec_stderr_setFile(path) {
		if (exec_closerr) {
			stdio.close(exec_io.stderr);
			exec_closerr = false;
		}
		var flags = stdio.flags.O_WRONLY|stdio.flags.O_CREAT|stdio.flags.O_SYNC;
		var p = path;
		if (path[0] == '+') {
			flags |= stdio.flags.O_APPEND;
			p = path.substring(1);
		}else{
			flags |= stdio.flags.O_TRUNC;
		}
		exec_io.stderr = stdio.open(p,flags);
		exec_closerr = true;
	}
	function exec_stderr_setNull() {
		if (exec_closerr) {
			stdio.close(exec_io.stderr);
			exec_closerr = false;
		}
		exec_io.stderr = stdio.open('/dev/null',stdio.flags.O_WRONLY);
		exec_closerr = true;
	}
	function exec_stderr_setOut() {
		if (exec_closerr) {
			stdio.close(exec_io.stderr);
			exec_closerr = false;
		}
		exec_io.stderr = exec_io.stdout;
		exec_closerr = exec_closout;
	}
	function exec_exit() {
		if (exec_closin) {
			stdio.close(exec_io.stdin);
			exec_closin = false;
		}
		var out = '';
		if (exec_bufferout)
			out = stdio.readAll(exec_bufferout);
		if (exec_closout) {
			stdio.close(exec_io.stdout);
			exec_closout = false;
		}
		if (exec_closerr) {
			stdio.close(exec_io.stderr);
			exec_closerr = false;
		}
		exec_active = null;
		exec_cmds = [];
		if (typeof exec_callback !== 'function')
			return;
		try{
			exec_callback(out);
		} catch(err) {
			console.log(err.fileName+':'+err.lineNumber+':'+err.columnNumber+':'+err.message);
			stdio.write(io.stderr,'Shell: internal error in command execution\n');
			io.exit(1);
			return;
		}
	}
	function exec_run(cb) {
		if (typeof cb === 'function')
			exec_callback = cb;
		var c;
		if (exec_skipto !== null) {
			if (exec_skipto == 'fi') {
				while ((c = exec_cmds.shift()) != null) {
					if (c.args[0] == 'fi')
						break;
				}
			}else if (exec_skipto == 'else') {
				while ((c = exec_cmds.shift()) != null) {
					if (c.args[0] == 'else' || c.args[0] == 'fi')
						break;
				}
			}
			exec_skipto = null;
		}else{
			c = exec_cmds.shift();
		}
		if (!c) {
			exec_exit();
			return;
		}
		exec_doCommand(c);
	}

	function help() {
		stdio.write(io.stdout,`
sh - command interpreter (shell)
Usage: sh [OPTION] [FILE]

Options:
-?	Print this help information

`);
	}

	function doShellExit(v) {
		history_save();
		stdio.write(io.stdout,'\n');
		has_exited = true;
		io.exit(v);
	}

	function resolvePATH(txt) {
		// special case of test command
		if (txt == '[')
			txt = 'test';
		if (typeof env.PATH === 'undefined')
			env.PATH = '/bin';
		var paths = env.PATH.split(':');
		var path = null;
		paths.forEach(function(p) {
			if (path)
				return;
			var rp = clite.resolvePath(txt,p);
			var st = stdio.stat(rp);
			if (st) {
				path = rp;
			}
		});
		return path;
	}

	function preprocess(txt) {
		var parts = txt.split('$');
		var pptxt = '';
		if (parts.length == 1)
			return txt;
		parts.forEach(function(p,i) {
			if (i > 0) {
				var b = p;
				var e = '';
				if (b[0] == '{') {
					var pi = b.indexOf('}');
					e = b.substring(pi+1);
					b = b.substring(1,pi);
				}else{
					var pi = b.indexOf(' ');
					if (pi > 0) {
						e = b.substring(pi);
						b = b.substring(0,pi);
					}
				}
				if (typeof env[b] === 'string') {
					b = env[b];
				}else{
					b = '';
				}
				pptxt += b+e;
				return;
			}
			pptxt += p;
		});
		txt = pptxt;
		parts = txt.split('`');
		pptxt = '';
		if (parts.length == 1)
			return txt;
		parts.forEach(function(p,i) {
			if (i > 0) {
				var b = p;
				var e = '';
				var pi = b.indexOf('`');
				if (pi > 0) {
					e = b.substring(pi);
					b = b.substring(0,pi);
				}
				// TODO: replace b with the output of the command in b (command substitution)
				pptxt = b+e;
				return;
			}
			pptxt += p;
		});
		return pptxt;
	}

	function tabfill(c) {
		var parts = clite.strToArgs(c);
		var ai = parts.length-1;
		if (ai < 0)
			return null;
		var a = parts[ai];
		var add = '';
		if (ai == 0) {
			// test for shell macros/builtins
			builtins.forEach(function(key) {
				if (add == '' && key.substring(0,a.length) == a) {
					add = key.substring(a.length);
				}
			});
			if (add == '') {
				// test for commands
				let pparts = env.PATH.split(':');
				pparts.forEach(function(pp) {
					if (add != '')
						return;
					let fd = stdio.open('/bin',stdio.flags.O_SEARCH|stdio.flags.O_DIRECTORY);
					let f = null;
					while (add == '' && (f = stdio.read(fd)) != null) {
						if (f.substring(0,a.length) == a) {
							add = f.substring(a.length)+' ';
						}
					}
					stdio.close(fd);
				});
			}
		}else if (a != '') {
			let p = clite.resolvePath(a);
			if (p[0] == '/') {
				let d = stdlib.dirname(p);
				let b = stdlib.basename(p);
				if (d == '')
					d = '/';
				let fd = stdio.open(d,stdio.flags.O_SEARCH|stdio.flags.O_DIRECTORY);
				if (fd) {
					let f = null;
					while (add == '' && (f = stdio.read(fd)) != null) {
						if (f.substring(0,b.length) == b) {
							add = f.substring(b.length);
							let fp = d+'/'+f;
							let st = stdio.stat(fp);
							if (st && st.type != stdio.types.FT_DIR)
								add += ' ';
						}
					}
					stdio.close(fd);
				}
			}
		}
		if (add == '')
			return null;
		stdio.write(io.stdout,'\b'+add);
		return c+add;
	}

	function writePrompt() {
		// generate the prompt
		var p = env.PS1;
		if (typeof p === 'undefined')
			p = '${USER}:${PWD}'

		var prompt = preprocess(p);
		if (stdlib.getuid() == 0) {
			prompt += '# ';
		}else{
			prompt += '$ ';
		}

		stdio.write(io.stdout,prompt);
	}

	function inputProcess(str) {
		let c = history_getCurrent();
		switch (str) {
		case String.fromCharCode(4):
		case 4:
			term.ttyctrl('raw',false);
			doShellExit(0);
			break;
		case '\t': // tab
		case 9:
			var ct = tabfill(c);
			if (ct != null) {
				c = ct;
			}else{
				stdio.write(io.stdout,'\b \b');
			}
			break;
		case '\n': // enter
			term.ttyctrl('raw',false);
			history_add(c);
			history_resetCurrent();
			exec_setCommand(c);
			exec_run(inputRead);
			return;
			break;
		case '\b':
		case 8:
			if (c.length > 0) {
				c = c.substring(0,c.length-1);
				stdio.write(io.stdout,'\b \b');
			}
			break;
		case -3: // down arrow
			var ct = history_down();
			if (ct != null) {
				for (var i=0; i<c.length; i++) {
					stdio.write(io.stdout,'\b \b');
				}
				c = ct;
				stdio.write(io.stdout,c);
			}
			break;
		case -4: // up arrow
			var ct = history_up();
			if (ct != null) {
				for (var i=0; i<c.length; i++) {
					stdio.write(io.stdout,'\b \b');
				}
				c = ct;
				stdio.write(io.stdout,c);
			}
			break;
		default:
			if (typeof str === 'string' && str.length == 1) {
				c += str;
			}
		}
		history_setCurrent(c);
		stdio.read(io.stdin,inputProcess);
	}

	function inputRead() {
		if (has_exited)
			return;
		// write the prompt
		writePrompt();
		// set tty to raw mode
		term.ttyctrl('raw',true);
		// then read from stdin
		stdio.read(io.stdin,inputProcess);
	}

	function main(argc,argv) {
		var f = null;
		var s = false;
		for (var i=1; i<argc; i++) {
			if (argv[i][0] == '-') {
				for (var j=1; j<argv[i].length; j++) {
					switch (argv[i][j]) {
					case '?':
						help();
						return 0;
						break;
					case 's':
						s = true;
						break;
					default:
						stdio.fprintf(io.stderr,'unknown argument -%c\n',argv[i][j]);
					}
				}
			}else if (f == null) {
				f = clite.resolvePath(argv[i]);
			}else{
				stdio.fprintf(io.stderr,'unknown argument - %s\n',argv[i]);
			}
		}

		// if argv[0] isn't the shell itself, then we're running a shell script
		if (!f && argv[0] != '/bin/sh' && argv[0] != 'sh') {
			f = clite.resolvePath(argv[0]);
			if (!f)
				return 1;
			// make the arguments readable by the shell script
			env['#'] = argc.toString();
			for (var i=0; i<argc; i++) {
				env[i.toString()] = argv[i];
			}
		}

		// run a shell script if one is specified
		if (f != null) {
			parser_queue(f);
			parser_run(function() {
				io.exit(0);
			});
		// run a shell script from stdin
		}else if (!stdio.isatty(io.stdin)) {
			if (!s)
				return 0;
			parser_stdin();
		// otherwise we have an interactive shell
		// so run /etc/shrc and ~/.shrc
		}else{
			parser_queue('/etc/shrc');
			parser_queue(env.HOME+'/.shrc');
			parser_run(function() {
				history_clear();
				history_load();
				inputRead();
			});
		}

		return null;
	}

	return main(args.length,args);
});

}