X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=gui.c;h=9d96e70f6949362b39b50fa1dc23e85327a9316a;hp=ef9410cc26dc6a26268a9873202495bd43ffaa7d;hb=becfb4be64a123630775b6517279ed20e4b498f8;hpb=5f511d41a111aa04189b32fd77d02e16f90ff2cc

diff --git a/gui.c b/gui.c
index ef9410cc..9d96e70f 100644
--- a/gui.c
+++ b/gui.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 1998-2014 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 1998 Andre Noll <maan@tuebingen.mpg.de>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -30,13 +30,14 @@
 INIT_GUI_ERRLISTS;
 static char *stat_content[NUM_STAT_ITEMS];
 
-static int signal_pipe;
-
 static struct gui_window {
 	WINDOW *win;
+	bool needs_update;
 } top, bot, sb, in, sep;
 
+/** How many lines of output to remember. */
 #define RINGBUFFER_SIZE 512
+
 struct rb_entry {
 	char *msg;
 	size_t len;
@@ -46,14 +47,18 @@ static struct ringbuffer *bot_win_rb;
 
 static unsigned scroll_position;
 
-static pid_t cmd_pid;
+static pid_t exec_pid;
 
-static int command_fds[2] = {-1, -1};
-static int stat_pipe = -1;
+static int exec_fds[2] = {-1, -1};
 static struct gui_args_info conf;
 static int loglevel;
 
-enum gui_select_mode{GETCH_MODE, COMMAND_MODE, EXTERNAL_MODE};
+/** Type of the process currently being executed. */
+enum exec_status {
+	EXEC_IDLE, /**< No process running. */
+	EXEC_DCMD, /**< para or display process running. */
+	EXEC_XCMD, /**< External process running. */
+};
 
 /**
  * Codes for various colors.
@@ -81,113 +86,64 @@ struct gui_command {
 
 static struct gui_theme theme;
 
-static void com_help(void);
-static void com_reread_conf(void);
-static void com_enlarge_top_win(void);
-static void com_shrink_top_win(void);
-static void com_version(void);
-__noreturn static void com_quit(void);
-static void com_refresh(void);
-static void com_ll_incr(void);
-static void com_ll_decr(void);
-static void com_prev_theme(void);
-static void com_next_theme(void);
-static void com_scroll_up(void);
-static void com_scroll_down(void);
-static void com_page_up(void);
-static void com_page_down(void);
-static void com_cancel_scrolling(void);
-static void com_scroll_top(void);
-
-static struct gui_command command_list[] = {
-	{
-		.key = "?",
-		.name = "help",
-		.description = "print help",
-		.handler = com_help
-	}, {
-		.key = "+",
-		.name = "enlarge_win",
-		.description = "enlarge the top window",
-		.handler = com_enlarge_top_win
-	}, {
-		.key = "-",
-		.name = "shrink_win",
-		.description = "shrink the top window",
-		.handler = com_shrink_top_win
-	}, {
-		.key = "r",
-		.name = "reread_conf",
-		.description = "reread configuration file",
-		.handler = com_reread_conf
-	}, {
-		.key = "q",
-		.name = "quit",
-		.description = "exit para_gui",
-		.handler = com_quit
-	}, {
-		.key = "^L",
-		.name = "refresh",
-		.description = "redraw the screen",
-		.handler = com_refresh
-	}, {
-		.key = ".",
-		.name = "next_theme",
-		.description = "switch to next theme",
-		.handler = com_next_theme
-	}, {
-		.key = ",",
-		.name = "prev_theme",
-		.description = "switch to previous stream",
-		.handler = com_prev_theme
-	}, {
-		.key = ">",
-		.name = "ll_incr",
-		.description = "increase loglevel (decreases verbosity)",
-		.handler = com_ll_incr
-	}, {
-		.key = "<",
-		.name = "ll_decr",
-		.description = "decrease loglevel (increases verbosity)",
-		.handler = com_ll_decr
-	}, {
-		.key = "V",
-		.name = "version",
-		.description = "show the para_gui version",
-		.handler = com_version
-	}, {
-		.key = "<up>",
-		.name = "scroll_up",
-		.description = "scroll up one line",
-		.handler = com_scroll_up
-	}, {
-		.key = "<down>",
-		.name = "scroll_down",
-		.description = "scroll down one line",
-		.handler = com_scroll_down
-	}, {
-		.key = "<ppage>",
-		.name = "page_up",
-		.description = "scroll up one page",
-		.handler = com_page_up
-	}, {
-		.key = "<npage>",
-		.name = "page_down",
-		.description = "scroll down one page",
-		.handler = com_page_down
-	}, {
-		.key = "<home>",
-		.name = "scroll_top",
-		.description = "scroll to top of buffer",
-		.handler = com_scroll_top
-	}, {
-		.key = "<end>",
-		.name = "cancel_scroll",
-		.description = "deactivate scroll mode",
-		.handler = com_cancel_scrolling
-	}, {
-		.handler = NULL
-	}
+#define GUI_COMMANDS \
+	GUI_COMMAND(help, "?", "print help") \
+	GUI_COMMAND(enlarge_top_win, "+", "enlarge the top window") \
+	GUI_COMMAND(shrink_top_win, "-", "shrink the top window") \
+	GUI_COMMAND(reread_conf, "r", "reread configuration file") \
+	GUI_COMMAND(quit, "q", "exit para_gui") \
+	GUI_COMMAND(refresh, "^L", "redraw the screen") \
+	GUI_COMMAND(next_theme, ".", "switch to next theme") \
+	GUI_COMMAND(prev_theme, ",", "switch to previous theme") \
+	GUI_COMMAND(ll_incr, ">", "increase loglevel (decreases verbosity)") \
+	GUI_COMMAND(ll_decr, "<", "decrease loglevel (increases verbosity)") \
+	GUI_COMMAND(version, "V", "show the para_gui version") \
+	GUI_COMMAND(scroll_up, "<up>", "scroll up one line") \
+	GUI_COMMAND(scroll_down, "<down>", "scroll_down") \
+	GUI_COMMAND(page_up, "<ppage>", "scroll up one page") \
+	GUI_COMMAND(page_down, "<npage>", "scroll down one page") \
+	GUI_COMMAND(scroll_top, "<home>", "scroll to top of buffer") \
+	GUI_COMMAND(cancel_scroll, "<end>", "deactivate scroll mode") \
+
+/* declare command handlers */
+#define GUI_COMMAND(_c, _k, _d) \
+	static void com_ ## _c(void);
+GUI_COMMANDS
+
+#undef GUI_COMMAND
+
+/* define command array */
+#define GUI_COMMAND(_c, _k, _d) \
+	{ \
+		.key = _k, \
+		.name = #_c, \
+		.description = _d, \
+		.handler = com_ ## _c \
+	},
+
+static struct gui_command command_list[] = {GUI_COMMANDS {.name = NULL}};
+
+struct input_task {
+	struct task *task;
+};
+
+struct status_task {
+	struct task *task;
+	pid_t pid;
+	char *buf;
+	int bufsize, loaded;
+	struct timeval next_exec;
+	int fd;
+};
+
+/** Stdout/stderr of the executing process is read in chunks of this size. */
+#define COMMAND_BUF_SIZE 32768
+
+struct exec_task {
+	struct task *task;
+	char command_buf[2][COMMAND_BUF_SIZE]; /* stdout/stderr of command */
+	int cbo[2]; /* command buf offsets */
+	unsigned flags[2]; /* passed to for_each_line() */
 };
 
 static int find_cmd_byname(char *name)
@@ -340,12 +296,23 @@ static int align_str(WINDOW* win, char *str, unsigned int len,
 		waddstr(win, str);
 	} else {
 		add_spaces(win, num / 2);
-		waddstr(win, str[0]? str: "");
+		waddstr(win, str);
 		add_spaces(win, num - num / 2);
 	}
 	return 1;
 }
 
+static void refresh_window(struct gui_window *gw)
+{
+	gw->needs_update = true;
+}
+
+static bool window_update_needed(void)
+{
+	return top.needs_update || bot.needs_update || sb.needs_update ||
+		in.needs_update || sep.needs_update;
+}
+
 __printf_2_3 static void print_in_bar(int color, const char *fmt,...)
 {
 	char *msg;
@@ -360,7 +327,7 @@ __printf_2_3 static void print_in_bar(int color, const char *fmt,...)
 	wmove(in.win, 0, 0);
 	align_str(in.win, msg, get_num_cols(&in), LEFT);
 	free(msg);
-	wrefresh(in.win);
+	refresh_window(&in);
 }
 
 static void print_status_bar(void)
@@ -456,7 +423,7 @@ static void redraw_bot_win(void)
 		waddstr(bot.win, rbe->msg);
 	}
 out:
-	wrefresh(bot.win);
+	refresh_window(&bot);
 }
 
 static void rb_add_entry(int color, char *msg)
@@ -503,7 +470,7 @@ __printf_2_3 static void outputf(int color, const char* fmt,...)
 	xvasprintf(&msg, fmt, ap);
 	va_end(ap);
 	rb_add_entry(color, msg);
-	wrefresh(bot.win);
+	refresh_window(&bot);
 }
 
 static int add_output_line(char *line, void *data)
@@ -530,23 +497,14 @@ static __printf_2_3 void curses_log(int ll, const char *fmt,...)
 		if (bytes > 0 && msg[bytes - 1] == '\n')
 			msg[bytes - 1] = '\0'; /* cut trailing newline */
 		rb_add_entry(color, msg);
-		wrefresh(bot.win);
-	} else if (cmd_pid <= 0) /* no external command running */
+		refresh_window(&bot);
+	} else if (exec_pid <= 0) /* no external command running */
 		vfprintf(stderr, fmt, ap);
 	va_end(ap);
 }
+/** The log function of para_gui, always set to curses_log(). */
 __printf_2_3 void (*para_log)(int, const char*, ...) = curses_log;
 
-static void setup_signal_handling(void)
-{
-	signal_pipe = para_signal_init();
-	para_install_sighandler(SIGINT);
-	para_install_sighandler(SIGTERM);
-	para_install_sighandler(SIGCHLD);
-	para_install_sighandler(SIGWINCH);
-	para_install_sighandler(SIGUSR1);
-}
-
 static void shutdown_curses(void)
 {
 	def_prog_mode();
@@ -582,11 +540,10 @@ static void print_stat_item(int i)
 		return;
 	tmp = make_message("%s%s%s", d.prefix, c, d.postfix);
 	wmove(top.win, d.y * top_lines / 100, d.x * COLS / 100);
-	wrefresh(top.win);
 	wattron(top.win, COLOR_PAIR(i + 1));
 	align_str(top.win, tmp, d.len * COLS / 100, d.align);
 	free(tmp);
-	wrefresh(top.win);
+	refresh_window(&top);
 }
 
 static int update_item(int item_num, char *buf)
@@ -640,44 +597,84 @@ static void clear_all_items(void)
 	}
 }
 
-static void status_post_select(fd_set *rfds)
+static void status_pre_select(struct sched *s, void *context)
 {
-	static char *buf;
-	static int bufsize, loaded;
-	int ret, ret2;
+	struct status_task *st = context;
+
+	if (st->fd >= 0)
+		para_fd_set(st->fd, &s->rfds, &s->max_fileno);
+	if (task_get_notification(st->task) < 0)
+		return sched_min_delay(s);
+	if (st->fd < 0)
+		sched_request_barrier_or_min_delay(&st->next_exec, s);
+}
+
+static int status_post_select(struct sched *s, void *context)
+{
+	struct status_task *st = context;
 	size_t sz;
+	int ret, ret2;
 
-	if (stat_pipe < 0)
-		return;
-	if (loaded >= bufsize) {
-		if (bufsize > 1000 * 1000) {
-			loaded = 0;
-			return;
+	ret = task_get_notification(st->task);
+	if (ret == -E_GUI_SIGCHLD && st->pid > 0) {
+		int exit_status;
+		if (waitpid(st->pid, &exit_status, WNOHANG) == st->pid) {
+			st->pid = 0;
+			PARA_ERROR_LOG("stat command exit status: %d",
+				exit_status);
+		}
+	}
+	if (st->fd < 0) {
+		int fds[3] = {0, 1, 0};
+		if (st->pid > 0)
+			return 0;
+		/* Avoid busy loop */
+		if (tv_diff(&st->next_exec, now, NULL) > 0)
+			return 0;
+		st->next_exec.tv_sec = now->tv_sec + 2;
+		ret = para_exec_cmdline_pid(&st->pid, conf.stat_cmd_arg, fds);
+		if (ret < 0)
+			return 0;
+		ret = mark_fd_nonblocking(fds[1]);
+		if (ret < 0) {
+			close(fds[1]);
+			return 0;
 		}
-		bufsize += bufsize + 1000;
-		buf = para_realloc(buf, bufsize);
+		st->fd = fds[1];
+		return 0;
 	}
-	assert(loaded < bufsize);
-	ret = read_nonblock(stat_pipe, buf + loaded, bufsize - loaded,
-		rfds, &sz);
-	loaded += sz;
-	ret2 = for_each_stat_item(buf, loaded, update_item);
+
+	if (st->loaded >= st->bufsize) {
+		if (st->bufsize > 1000 * 1000) {
+			st->loaded = 0;
+			return 0;
+		}
+		st->bufsize += st->bufsize + 1000;
+		st->buf = para_realloc(st->buf, st->bufsize);
+	}
+	assert(st->loaded < st->bufsize);
+	ret = read_nonblock(st->fd, st->buf + st->loaded,
+		st->bufsize - st->loaded, &s->rfds, &sz);
+	st->loaded += sz;
+	ret2 = for_each_stat_item(st->buf, st->loaded, update_item);
 	if (ret < 0 || ret2 < 0) {
-		loaded = 0;
-		PARA_NOTICE_LOG("closing stat pipe: %s\n", para_strerror(-ret));
-		close(stat_pipe);
-		stat_pipe = -1;
+		st->loaded = 0;
+		PARA_NOTICE_LOG("closing stat pipe: %s\n",
+			para_strerror(ret < 0? -ret : -ret2));
+		close(st->fd);
+		st->fd = -1;
 		clear_all_items();
 		free(stat_content[SI_BASENAME]);
 		stat_content[SI_BASENAME] =
 			para_strdup("stat command terminated!?");
 		print_all_items();
-		return;
+		return 0;
 	}
 	sz = ret2; /* what is left */
-	if (sz > 0 && sz < loaded)
-		memmove(buf, buf + loaded - sz, sz);
-	loaded = sz;
+	if (sz > 0 && sz < st->loaded)
+		memmove(st->buf, st->buf + st->loaded - sz, sz);
+	st->loaded = sz;
+	return 0;
 }
 
 /*
@@ -690,7 +687,7 @@ static void init_wins(int top_lines)
 	int bot_lines = LINES - top_lines - 3, sb_lines = 1, in_lines = 1,
 		sep_lines = 1;
 
-	assume_default_colors(theme.default_fg, theme.default_bg);
+	assume_default_colors(theme.dflt.fg, theme.dflt.bg);
 	if (top.win) {
 		wresize(top.win, top_lines, COLS);
 		mvwin(top.win, top_y, 0);
@@ -762,16 +759,16 @@ static void init_colors_or_die(void)
 		die(EXIT_FAILURE, "fatal: failed to start colors\n");
 	FOR_EACH_STATUS_ITEM(i)
 		if (theme.data[i].len)
-			init_pair_or_die(i + 1, theme.data[i].fg,
-				theme.data[i].bg);
-	init_pair_or_die(COLOR_STATUSBAR, theme.sb_fg, theme.sb_bg);
-	init_pair_or_die(COLOR_COMMAND, theme.cmd_fg, theme.cmd_bg);
-	init_pair_or_die(COLOR_OUTPUT, theme.output_fg, theme.output_bg);
-	init_pair_or_die(COLOR_MSG, theme.msg_fg, theme.msg_bg);
-	init_pair_or_die(COLOR_ERRMSG, theme.err_msg_fg, theme.err_msg_bg);
-	init_pair_or_die(COLOR_SEPARATOR, theme.sep_fg, theme.sep_bg);
-	init_pair_or_die(COLOR_TOP, theme.default_fg, theme.default_bg);
-	init_pair_or_die(COLOR_BOT, theme.default_fg, theme.default_bg);
+			init_pair_or_die(i + 1, theme.data[i].color.fg,
+				theme.data[i].color.bg);
+	init_pair_or_die(COLOR_STATUSBAR, theme.sb.fg, theme.sb.bg);
+	init_pair_or_die(COLOR_COMMAND, theme.cmd.fg, theme.cmd.bg);
+	init_pair_or_die(COLOR_OUTPUT, theme.output.fg, theme.output.bg);
+	init_pair_or_die(COLOR_MSG, theme.msg.fg, theme.msg.bg);
+	init_pair_or_die(COLOR_ERRMSG, theme.err_msg.fg, theme.err_msg.bg);
+	init_pair_or_die(COLOR_SEPARATOR, theme.sep.fg, theme.sep.bg);
+	init_pair_or_die(COLOR_TOP, theme.dflt.fg, theme.dflt.bg);
+	init_pair_or_die(COLOR_BOT, theme.dflt.fg, theme.dflt.bg);
 }
 
 /* (Re-)initialize the curses library. */
@@ -779,7 +776,7 @@ static void init_curses(void)
 {
 	if (curses_active())
 		return;
-	if (top.win && refresh() == ERR) /* refresh is really needed */
+	if (refresh() == ERR) /* refresh is really needed */
 		die(EXIT_FAILURE, "refresh() failed\n");
 	if (LINES < theme.lines_min || COLS < theme.cols_min)
 		die(EXIT_FAILURE, "Terminal (%dx%d) too small"
@@ -799,23 +796,6 @@ static void init_curses(void)
 	// noecho(); /* don't echo input */
 }
 
-static void check_sigchld(void)
-{
-	int ret;
-	pid_t pid;
-
-reap_next_child:
-	ret = para_reap_child(&pid);
-	if (ret <= 0)
-		return;
-	if (pid == cmd_pid) {
-		cmd_pid = 0;
-		init_curses();
-		print_in_bar(COLOR_MSG, " ");
-	}
-	goto reap_next_child;
-}
-
 /*
  * This sucker modifies its first argument. *handler and *arg are
  * pointers to 0-terminated strings (inside line). Crap.
@@ -891,15 +871,32 @@ static void parse_config_file_or_die(bool override)
 		}
 		goto out;
 	}
+	/*
+	 * When the gengetopt config file parser is called more than once, any
+	 * key map arguments found in the config file are _appended_ to the old
+	 * values, even though we turn on ->override. We want the new arguments
+	 * to replace the old ones, so we must empty the key_map_arg array
+	 * first. Unfortunately, this also clears any key map arguments given
+	 * at the command line.
+	 */
+	if (override) {
+		int i;
+		for (i = 0; i < conf.key_map_given; i++) {
+			free(conf.key_map_arg[i]);
+			conf.key_map_arg[i] = NULL;
+		}
+		conf.key_map_given = 0;
+	}
+
 	gui_cmdline_parser_config_file(config_file, &conf, &params);
 	loglevel = get_loglevel_by_name(conf.loglevel_arg);
 	check_key_map_args_or_die();
-	theme_init(conf.theme_arg, &theme);
 	err = false;
 out:
 	free(config_file);
 	if (err)
 		exit(EXIT_FAILURE);
+	theme_init(conf.theme_arg, &theme);
 }
 
 /* reread configuration, terminate on errors */
@@ -918,149 +915,118 @@ static void reread_conf(void)
 /*
  * React to various signal-related events
  */
-static void signal_post_select(fd_set *rfds)
+static int signal_post_select(struct sched *s, __a_unused void *context)
 {
-	int ret = para_next_signal(rfds);
+	int ret = para_next_signal(&s->rfds);
+
 	if (ret <= 0)
-		return;
+		return 0;
 	switch (ret) {
 	case SIGTERM:
 		die(EXIT_FAILURE, "only the good die young (caught SIGTERM)\n");
-		return;
-	case SIGWINCH:
-		if (curses_active()) {
-			shutdown_curses();
-			init_curses();
-			redraw_bot_win();
-		}
-		return;
+		return 1;
 	case SIGINT:
 		PARA_WARNING_LOG("caught SIGINT, reset\n");
 		/* Nothing to do. SIGINT killed our child which gets noticed
 		 * by do_select and resets everything.
 		 */
-		return;
+		return 1;
 	case SIGUSR1:
 		PARA_NOTICE_LOG("got SIGUSR1, rereading configuration\n");
 		reread_conf();
-		return;
+		return 1;
 	case SIGCHLD:
-		check_sigchld();
-		return;
-	}
-}
-
-static void status_pre_select(fd_set *rfds, int *max_fileno, struct timeval *tv)
-{
-	static struct timeval next_exec, atm, diff;
-	int ret, fds[3] = {0, 1, 0};
-	pid_t pid;
-
-	if (stat_pipe >= 0)
-		goto success;
-	/* Avoid busy loop */
-	gettimeofday(&atm, NULL);
-	if (tv_diff(&next_exec, &atm, &diff) > 0) {
-		if (tv_diff(&diff, tv, NULL) < 0)
-			*tv = diff;
-		return;
-	}
-	next_exec.tv_sec = atm.tv_sec + 2;
-	ret = para_exec_cmdline_pid(&pid, conf.stat_cmd_arg, fds);
-	if (ret < 0)
-		return;
-	ret = mark_fd_nonblocking(fds[1]);
-	if (ret < 0) {
-		close(fds[1]);
-		return;
+		task_notify_all(s, E_GUI_SIGCHLD);
+		return 1;
 	}
-	stat_pipe = fds[1];
-success:
-	para_fd_set(stat_pipe, rfds, max_fileno);
+	return 1;
 }
 
-#define COMMAND_BUF_SIZE 32768
-
-static enum gui_select_mode get_select_mode(void)
+static enum exec_status exec_status(void)
 {
-	if (command_fds[0] >= 0 || command_fds[1] >= 0)
-		return COMMAND_MODE;
-	if (cmd_pid > 0)
-		return EXTERNAL_MODE;
-	return GETCH_MODE;
+	if (exec_fds[0] >= 0 || exec_fds[1] >= 0)
+		return EXEC_DCMD;
+	if (exec_pid > 0)
+		return EXEC_XCMD;
+	return EXEC_IDLE;
 }
 
-static void command_pre_select(fd_set *rfds, int *max_fileno)
+static void exec_pre_select(struct sched *s, void *context)
 {
-	enum gui_select_mode mode = get_select_mode();
-
-	if (mode != COMMAND_MODE)
-		return;
-	if (command_fds[0] >= 0)
-		para_fd_set(command_fds[0], rfds, max_fileno);
-	if (command_fds[1] >= 0)
-		para_fd_set(command_fds[1], rfds, max_fileno);
+	struct exec_task *et = context;
+	if (exec_fds[0] >= 0)
+		para_fd_set(exec_fds[0], &s->rfds, &s->max_fileno);
+	if (exec_fds[1] >= 0)
+		para_fd_set(exec_fds[1], &s->rfds, &s->max_fileno);
+	if (task_get_notification(et->task) < 0)
+		sched_min_delay(s);
 }
 
-static void command_post_select(fd_set *rfds)
+static int exec_post_select(struct sched *s, void *context)
 {
+	struct exec_task *ct = context;
 	int i, ret;
-	static char command_buf[2][COMMAND_BUF_SIZE];
-	static int cbo[2]; /* command buf offsets */
-	static unsigned flags[2]; /* for for_each_line() */
-	enum gui_select_mode mode = get_select_mode();
 
-	if (mode != COMMAND_MODE)
-		return;
+	ret = task_get_notification(ct->task);
+	if (ret == -E_GUI_SIGCHLD && exec_pid > 0) {
+		int exit_status;
+		if (waitpid(exec_pid, &exit_status, WNOHANG) == exec_pid) {
+			exec_pid = 0;
+			init_curses();
+			PARA_INFO_LOG("command exit status: %d", exit_status);
+			print_in_bar(COLOR_MSG, " ");
+		}
+	}
 	for (i = 0; i < 2; i++) {
 		size_t sz;
-		if (command_fds[i] < 0)
+		if (exec_fds[i] < 0)
 			continue;
-		ret = read_nonblock(command_fds[i],
-			command_buf[i] + cbo[i],
-			COMMAND_BUF_SIZE - 1 - cbo[i], rfds, &sz);
-		cbo[i] += sz;
-		sz = cbo[i];
-		cbo[i] = for_each_line(flags[i], command_buf[i], cbo[i],
-			add_output_line, &i);
-		if (sz != cbo[i]) { /* at least one line found */
-			wrefresh(bot.win);
-			flags[i] = 0;
+		ret = read_nonblock(exec_fds[i],
+			ct->command_buf[i] + ct->cbo[i],
+			COMMAND_BUF_SIZE - 1 - ct->cbo[i], &s->rfds, &sz);
+		ct->cbo[i] += sz;
+		sz = ct->cbo[i];
+		ct->cbo[i] = for_each_line(ct->flags[i], ct->command_buf[i],
+			ct->cbo[i], add_output_line, &i);
+		if (sz != ct->cbo[i]) { /* at least one line found */
+			refresh_window(&bot);
+			ct->flags[i] = 0;
 		}
-		if (ret < 0 || cmd_pid == 0) {
+		if (ret < 0 || exec_pid == 0) {
 			if (ret < 0)
 				PARA_NOTICE_LOG("closing command fd %d: %s",
 					i, para_strerror(-ret));
-			close(command_fds[i]);
-			command_fds[i] = -1;
-			flags[i] = 0;
-			cbo[i] = 0;
-			if (command_fds[!i] < 0) /* both fds closed */
-				return;
+			close(exec_fds[i]);
+			exec_fds[i] = -1;
+			ct->flags[i] = 0;
+			ct->cbo[i] = 0;
+			if (exec_fds[!i] < 0) /* both fds closed */
+				return 1;
 		}
-		if (cbo[i] == COMMAND_BUF_SIZE - 1) {
+		if (ct->cbo[i] == COMMAND_BUF_SIZE - 1) {
 			PARA_NOTICE_LOG("discarding overlong line");
-			cbo[i] = 0;
-			flags[i] = FELF_DISCARD_FIRST;
+			ct->cbo[i] = 0;
+			ct->flags[i] = FELF_DISCARD_FIRST;
 		}
 	}
+	return 0;
 }
 
-static void input_pre_select(fd_set *rfds, int *max_fileno)
+static void input_pre_select(struct sched *s, __a_unused void *context)
 {
-	enum gui_select_mode mode = get_select_mode();
-
-	if (mode == GETCH_MODE || mode == COMMAND_MODE)
-		para_fd_set(STDIN_FILENO, rfds, max_fileno);
+	if (exec_status() != EXEC_XCMD)
+		para_fd_set(STDIN_FILENO, &s->rfds, &s->max_fileno);
+	if (window_update_needed())
+		sched_min_delay(s);
 }
 
 /* read from command pipe and print data to bot window */
-static void exec_and_display_cmd(const char *cmd)
+static void exec_and_display(const char *file_and_args)
 {
 	int ret, fds[3] = {0, 1, 1};
 
-	outputf(COLOR_COMMAND, "%s", cmd);
-	ret = para_exec_cmdline_pid(&cmd_pid, cmd, fds);
+	outputf(COLOR_COMMAND, "%s", file_and_args);
+	ret = para_exec_cmdline_pid(&exec_pid, file_and_args, fds);
 	if (ret < 0)
 		return;
 	ret = mark_fd_nonblocking(fds[1]);
@@ -1069,42 +1035,36 @@ static void exec_and_display_cmd(const char *cmd)
 	ret = mark_fd_nonblocking(fds[2]);
 	if (ret < 0)
 		goto fail;
-	command_fds[0] = fds[1];
-	command_fds[1] = fds[2];
+	exec_fds[0] = fds[1];
+	exec_fds[1] = fds[2];
+	print_in_bar(COLOR_MSG, "hit any key to abort\n");
 	return;
 fail:
 	PARA_ERROR_LOG("%s\n", para_strerror(-ret));
-	close(command_fds[0]);
-	close(command_fds[1]);
+	close(exec_fds[0]);
+	close(exec_fds[1]);
 }
 
-static void para_cmd(char *cmd)
+static void exec_para(const char *args)
 {
-	char *c;
+	char *file_and_args;
 
-	print_in_bar(COLOR_MSG, "executing client command, hit any key to abort\n");
-	c = make_message(BINDIR "/para_client -- %s", cmd);
-	exec_and_display_cmd(c);
-	free(c);
-}
-
-static void display_cmd(char *cmd)
-{
-	print_in_bar(COLOR_MSG, "executing display command, hit any key to abort");
-	exec_and_display_cmd(cmd);
+	file_and_args = make_message(BINDIR "/para_client -- %s", args);
+	exec_and_display(file_and_args);
+	free(file_and_args);
 }
 
 /*
  * shutdown curses and stat pipe before executing external commands
  */
-static void external_cmd(char *cmd)
+static void exec_external(char *file_and_args)
 {
 	int fds[3] = {-1, -1, -1};
 
-	if (cmd_pid)
+	if (exec_pid)
 		return;
 	shutdown_curses();
-	para_exec_cmdline_pid(&cmd_pid, cmd, fds);
+	para_exec_cmdline_pid(&exec_pid, file_and_args, fds);
 }
 
 static void handle_command(int c)
@@ -1125,11 +1085,11 @@ static void handle_command(int c)
 			continue;
 		}
 		if (*handler == 'd')
-			display_cmd(arg);
+			exec_and_display(arg);
 		else if (*handler == 'x')
-			external_cmd(arg);
+			exec_external(arg);
 		else if (*handler == 'p')
-			para_cmd(arg);
+			exec_para(arg);
 		else if (*handler == 'i') {
 			int num = find_cmd_byname(arg);
 			if (num >= 0)
@@ -1149,57 +1109,44 @@ static void handle_command(int c)
 		km_keyname(c));
 }
 
-static void input_post_select(void)
+static int input_post_select(__a_unused struct sched *s, __a_unused void *context)
 {
 	int ret;
-	enum gui_select_mode mode = get_select_mode();
+	enum exec_status exs = exec_status();
 
-	if (mode == EXTERNAL_MODE)
-		return;
+	if (exs == EXEC_XCMD)
+		return 0;
+	if (window_update_needed()) {
+		if (top.needs_update)
+			assert(wnoutrefresh(top.win) == OK);
+		if (bot.needs_update)
+			assert(wnoutrefresh(bot.win) == OK);
+		if (sep.needs_update)
+			assert(wnoutrefresh(sep.win) == OK);
+		if (sb.needs_update)
+			assert(wnoutrefresh(sb.win) == OK);
+		if (in.needs_update)
+			assert(wnoutrefresh(in.win) == OK);
+		doupdate();
+		top.needs_update = bot.needs_update = sb.needs_update =
+			in.needs_update = sep.needs_update = false;
+	}
 	ret = wgetch(top.win);
-	if (ret == ERR || ret == KEY_RESIZE)
-		return;
-	if (mode == GETCH_MODE)
-		return handle_command(ret);
-	if (cmd_pid != 0)
-		kill(cmd_pid, SIGTERM);
-}
-
-static void signal_pre_select(fd_set *rfds, int *max_fileno)
-{
-	para_fd_set(signal_pipe, rfds, max_fileno);
-}
-
-/*
- * This is the core select loop. It checks the following fds:
- *
- * - signal pipe
- * - stdin
- * - stdout/stderr of display or internal commands
- */
-__noreturn static void do_select(void)
-{
-	fd_set rfds;
-	int ret, max_fileno;
-	struct timeval tv;
-
-repeat:
-	tv.tv_sec = conf.timeout_arg  / 1000;
-	tv.tv_usec = (conf.timeout_arg % 1000) * 1000;
-	FD_ZERO(&rfds);
-	max_fileno = 0;
-	status_pre_select(&rfds, &max_fileno, &tv);
-	signal_pre_select(&rfds, &max_fileno);
-	command_pre_select(&rfds, &max_fileno);
-	input_pre_select(&rfds, &max_fileno);
-	ret = para_select(max_fileno + 1, &rfds, NULL, &tv);
-	if (ret <= 0)
-		goto repeat; /* skip fd checks */
-	signal_post_select(&rfds);
-	command_post_select(&rfds);
-	status_post_select(&rfds);
-	input_post_select();
-	goto repeat;
+	if (ret == ERR)
+		return 0;
+	if (ret == KEY_RESIZE) {
+		if (curses_active()) {
+			shutdown_curses();
+			init_curses();
+			redraw_bot_win();
+		}
+		return 0;
+	}
+	if (exs == EXEC_IDLE)
+		handle_command(ret);
+	else if (exec_pid > 0)
+		kill(exec_pid, SIGTERM);
+	return 0;
 }
 
 static void print_scroll_msg(void)
@@ -1235,7 +1182,7 @@ static void com_scroll_top(void)
 	print_in_bar(COLOR_ERRMSG, "top of buffer is shown\n");
 }
 
-static void com_cancel_scrolling(void)
+static void com_cancel_scroll(void)
 {
 
 	if (scroll_position == 0) {
@@ -1301,7 +1248,7 @@ static void com_scroll_down(void)
 	wmove(bot.win, bot_lines - rbe_lines, 0);
 	wattron(bot.win, COLOR_PAIR(rbe->color));
 	waddstr(bot.win, rbe->msg);
-	wrefresh(bot.win);
+	refresh_window(&bot);
 	print_scroll_msg();
 }
 
@@ -1338,7 +1285,7 @@ static void com_scroll_up(void)
 			break;
 		i--;
 	}
-	wrefresh(bot.win);
+	refresh_window(&bot);
 	print_scroll_msg();
 	return;
 err_out:
@@ -1470,6 +1417,83 @@ __noreturn static void print_help_and_die(void)
 	exit(0);
 }
 
+static int setup_tasks_and_schedule(void)
+{
+	int ret;
+	struct exec_task exec_task = {.task = NULL};
+	struct status_task status_task = {.fd = -1};
+	struct input_task input_task = {.task = NULL};
+	struct signal_task *signal_task;
+	struct sched sched = {
+		.default_timeout = {
+			.tv_sec = conf.timeout_arg  / 1000,
+			.tv_usec = (conf.timeout_arg % 1000) * 1000,
+		},
+	};
+
+	exec_task.task = task_register(&(struct task_info) {
+		.name = "exec",
+		.pre_select = exec_pre_select,
+		.post_select = exec_post_select,
+		.context = &exec_task,
+	}, &sched);
+
+	status_task.task = task_register(&(struct task_info) {
+		.name = "status",
+		.pre_select = status_pre_select,
+		.post_select = status_post_select,
+		.context = &status_task,
+	}, &sched);
+
+	input_task.task = task_register(&(struct task_info) {
+		.name = "input",
+		.pre_select = input_pre_select,
+		.post_select = input_post_select,
+		.context = &input_task,
+	}, &sched);
+
+	signal_task = signal_init_or_die();
+	para_install_sighandler(SIGINT);
+	para_install_sighandler(SIGTERM);
+	para_install_sighandler(SIGCHLD);
+	para_install_sighandler(SIGUSR1);
+	signal_task->task = task_register(&(struct task_info) {
+		.name = "signal",
+		.pre_select = signal_pre_select,
+		.post_select = signal_post_select,
+		.context = signal_task,
+	}, &sched);
+	ret = schedule(&sched);
+	sched_shutdown(&sched);
+	signal_shutdown(signal_task);
+	return ret;
+}
+
+/**
+ * The main function of para_gui.
+ *
+ * \param argc Usual argument count.
+ * \param argv Usual argument vector.
+ *
+ * After initialization para_gui registers the following tasks to the paraslash
+ * scheduler: status, exec, signal, input.
+ *
+ * The status task executes the para_audioc stat command to obtain the status
+ * of para_server and para_audiod, and displays this information in the top
+ * window of para_gui.
+ *
+ * The exec task is responsible for printing the output of the currently
+ * running executable to the bottom window.
+ *
+ * The signal task performs suitable actions according to any signals received.
+ * For example it refreshes all windows on terminal size changes and resets the
+ * terminal on \p SIGTERM.
+ *
+ * The input task reads single key strokes from stdin. For each key pressed, it
+ * executes the command handler associated with this key.
+ *
+ * \return \p EXIT_SUCCESS or \p EXIT_FAILURE.
+ */
 int main(int argc, char *argv[])
 {
 	gui_cmdline_parser(argc, argv, &conf); /* exits on errors */
@@ -1478,10 +1502,9 @@ int main(int argc, char *argv[])
 	if (conf.help_given || conf.detailed_help_given)
 		print_help_and_die();
 	parse_config_file_or_die(false /* override */);
-	setup_signal_handling();
 	bot_win_rb = ringbuffer_new(RINGBUFFER_SIZE);
 	setlocale(LC_CTYPE, "");
 	initscr(); /* needed only once, always successful */
 	init_curses();
-	do_select();
+	return setup_tasks_and_schedule() < 0? EXIT_FAILURE : EXIT_SUCCESS;
 }