From: Andre Noll <maan@systemlinux.org>
Date: Wed, 23 Jul 2014 15:29:29 +0000 (+0200)
Subject: Merge branch 't/sched_improvements'
X-Git-Tag: v0.5.3~8
X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=commitdiff_plain;h=8aa9d0cddfefb882cfd8e7cadbeea5cce31b731f

Merge branch 't/sched_improvements'

Cooking for two months. This merge required to also patch gui.c due
to semantic conflics against the changes introduced by the gui_sched
branch which was merged to master in commit d15d8509 two weeks ago.
Also a small fix for server.c is needed to squelch a compiler warning
since the global "now" variable has become a const pointer.

* t/sched_improvements: (36 commits)
  audiod: Fix use after free on exit.
  sched: Mark global now pointer as const.
  sched: Directly pass context pointer to pre/post_select().
  sched: kill task->dead.
  sched: Do not shadow task_info in struct task.
  sched: Dont use fixed-size buffer for task names.
  sched: Rename task->error to tast->status.
  sched: Rename task->status to task->name.
  sched: Make struct task private to sched.c.
  sched: Introduce task_status().
  sched: Remove ->owned_by_sched.
  sched: Remove register_task().
  task_register() conversion: grab client task
  task_register() conversion: audiod status task
  task_register() conversion: audiod command task
  task_register() conversion: client task
  task_register() conversion: client supervisor task
  task_register() conversion: client exec task
  task_register() conversion: afs command task
  task_register() conversion: vss task
  ...
---

8aa9d0cddfefb882cfd8e7cadbeea5cce31b731f
diff --cc NEWS
index c613d672,642c1fc4..311aca2b
--- a/NEWS
+++ b/NEWS
@@@ -5,8 -5,7 +5,11 @@@ NEW
  0.5.3 (to be released) "symbolic synchronization"
  -------------------------------------------------
  
++Not many new features, but lots of fixes and usability improvements.
++
 +	- para_gui has been converted to use the paraslash scheduler.
  	- Various alsa-related fixes, mostly for the raspberry pi.
++	- Many scheduler improvements and cleanups.
  	- The test suite has been extended to include sanity checks
  	  for the generated man pages.
  	- ao_writer fixes. This writer was in a quite bad shape. Many
diff --cc gui.c
index b077b00a,5a2e659d..92b7f7cf
--- a/gui.c
+++ b/gui.c
@@@ -84,66 -80,130 +84,66 @@@ struct gui_command 
  	void (*handler)(void);
  };
  
 -struct stat_item {
 -	char name[MAXLINE];
 -	char prefix[MAXLINE];
 -	char postfix[MAXLINE];
 -	unsigned y;
 -	unsigned x;
 -	unsigned len;
 -	int fg, bg;
 -	int align;
 -	char content[MAXLINE];
 +static struct gui_theme theme;
 +
 +#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 task *task;
  };
  
 -static struct gui_theme theme;
 +struct status_task {
- 	struct task task;
++	struct task *task;
 +	pid_t pid;
 +	char *buf;
 +	int bufsize, loaded;
 +	struct timeval next_exec;
 +	int fd;
 +};
  
 -static int _argc;
 -static char **_argv;
 -
 -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
 -	}
 +/** Stdout/stderr of the executing process is read in chunks of this size. */
 +#define COMMAND_BUF_SIZE 32768
 +
 +struct exec_task {
- 	struct task 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)
@@@ -597,151 -802,6 +597,151 @@@ static void clear_all_items(void
  	}
  }
  
- static void status_pre_select(struct sched *s, struct task *t)
++static void status_pre_select(struct sched *s, void *context)
 +{
- 	struct status_task *st = container_of(t, struct status_task, task);
++	struct status_task *st = context;
 +
 +	if (st->fd >= 0)
 +		para_fd_set(st->fd, &s->rfds, &s->max_fileno);
- 	if (task_get_notification(t) < 0)
++	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, struct task *t)
++static int status_post_select(struct sched *s, void *context)
 +{
- 	struct status_task *st = container_of(t, struct status_task, task);
++	struct status_task *st = context;
 +	size_t sz;
 +	int ret, ret2;
 +
- 	ret = task_get_notification(t);
++	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;
 +		}
 +		st->fd = fds[1];
 +		return 0;
 +	}
 +
 +	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) {
 +		st->loaded = 0;
 +		PARA_NOTICE_LOG("closing stat pipe: %s\n", para_strerror(-ret));
 +		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 0;
 +	}
 +	sz = ret2; /* what is left */
 +	if (sz > 0 && sz < st->loaded)
 +		memmove(st->buf, st->buf + st->loaded - sz, sz);
 +	st->loaded = sz;
 +	return 0;
 +}
 +
 +/*
 + * init all windows
 + */
 +static void init_wins(int top_lines)
 +{
 +	int top_y = 0, bot_y = top_lines + 1, sb_y = LINES - 2,
 +		in_y = LINES - 1, sep_y = top_lines;
 +	int bot_lines = LINES - top_lines - 3, sb_lines = 1, in_lines = 1,
 +		sep_lines = 1;
 +
 +	assume_default_colors(theme.dflt.fg, theme.dflt.bg);
 +	if (top.win) {
 +		wresize(top.win, top_lines, COLS);
 +		mvwin(top.win, top_y, 0);
 +
 +		wresize(sb.win, sb_lines, COLS);
 +		mvwin(sb.win, sb_y, 0);
 +
 +		wresize(sep.win, sep_lines, COLS);
 +		mvwin(sep.win, sep_y, 0);
 +
 +		wresize(bot.win, bot_lines, COLS);
 +		mvwin(bot.win, bot_y, 0);
 +
 +		wresize(in.win, in_lines, COLS);
 +		mvwin(in.win, in_y, 0);
 +	} else {
 +		sep.win = newwin(sep_lines, COLS, sep_y, 0);
 +		top.win = newwin(top_lines, COLS, top_y, 0);
 +		bot.win = newwin(bot_lines, COLS, bot_y, 0);
 +		sb.win = newwin(sb_lines, COLS, sb_y, 0);
 +		in.win = newwin(in_lines, COLS, in_y, 0);
 +		if (!top.win || !bot.win || !sb.win || !in.win || !sep.win)
 +			die(EXIT_FAILURE, "Error: Cannot create curses windows\n");
 +		wclear(bot.win);
 +		wclear(sb.win);
 +		wclear(in.win);
 +		scrollok(bot.win, 1);
 +		wattron(sb.win, COLOR_PAIR(COLOR_STATUSBAR));
 +		wattron(sep.win, COLOR_PAIR(COLOR_SEPARATOR));
 +		wattron(bot.win, COLOR_PAIR(COLOR_BOT));
 +		wattron(top.win, COLOR_PAIR(COLOR_TOP));
 +		nodelay(top.win, 1);
 +		nodelay(bot.win, 1);
 +		nodelay(sb.win, 1);
 +		nodelay(in.win, 0);
 +
 +		keypad(top.win, 1);
 +		keypad(bot.win, 1);
 +		keypad(sb.win, 1);
 +		keypad(in.win, 1);
 +	}
 +	wmove(sep.win, 0, 0);
 +	whline(sep.win, theme.sep_char, COLS);
 +	wclear(top.win);
 +	print_all_items();
 +	//wclear(bot.win);
 +	wnoutrefresh(top.win);
 +	wnoutrefresh(bot.win);
 +	print_status_bar();
 +	wnoutrefresh(sb.win);
 +	wnoutrefresh(in.win);
 +	wnoutrefresh(sep.win);
 +	doupdate();
 +}
 +
  static void init_pair_or_die(short pair, short f, short b)
  {
  	if (init_pair(pair, f, b) == ERR)
@@@ -897,128 -923,206 +897,129 @@@ static void reread_conf(void
  /*
   * React to various signal-related events
   */
- static int signal_post_select(struct sched *s, __a_unused struct task *t)
 -static void handle_signal(int sig)
++static int signal_post_select(struct sched *s, __a_unused void *context)
  {
 -	switch (sig) {
 +	int ret = para_next_signal(&s->rfds);
 +
 +	if (ret <= 0)
 +		return 0;
 +	switch (ret) {
  	case SIGTERM:
 -		msg_n_exit(EXIT_FAILURE,
 -			"only the good die young (caught SIGTERM))\n");
 -		return;
 -	case SIGWINCH:
 -		if (curses_active) {
 -			shutdown_curses();
 -			init_curses();
 -			redraw_bot_win();
 -		}
 -		return;
 +		die(EXIT_FAILURE, "only the good die young (caught SIGTERM)\n");
 +		return 1;
  	case SIGINT:
 -		PARA_WARNING_LOG("caught SIGINT, reset");
 +		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");
 -		com_reread_conf();
 -		return;
 +		PARA_NOTICE_LOG("got SIGUSR1, rereading configuration\n");
 +		reread_conf();
 +		return 1;
  	case SIGCHLD:
 -		check_sigchld();
 -		return;
 +		task_notify_all(s, E_GUI_SIGCHLD);
 +		return 1;
  	}
 +	return 1;
  }
  
 -static void status_pre_select(fd_set *rfds, int *max_fileno, struct timeval *tv)
 +static enum exec_status exec_status(void)
  {
 -	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;
 -	}
 -	stat_pipe = fds[1];
 -success:
 -	para_fd_set(stat_pipe, rfds, max_fileno);
 +	if (exec_fds[0] >= 0 || exec_fds[1] >= 0)
 +		return EXEC_DCMD;
 +	if (exec_pid > 0)
 +		return EXEC_XCMD;
 +	return EXEC_IDLE;
  }
  
- static void exec_pre_select(struct sched *s, struct task *t)
 -#define COMMAND_BUF_SIZE 32768
++static void exec_pre_select(struct sched *s, void *context)
 +{
++	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(t) < 0)
++	if (task_get_notification(et->task) < 0)
 +		sched_min_delay(s);
 +}
  
- static int exec_post_select(struct sched *s, struct task *t)
 -/*
 - * This is the core select loop. Besides the (internal) signal
 - * pipe, the following other fds are checked according to the mode:
 - *
 - * GETCH_MODE: check stdin, return when key is pressed
 - *
 - * COMMAND_MODE: check command fds and stdin. Return when peer has closed both
 - * stdout and stderr or when any key is pressed.
 - *
 - * EXTERNAL_MODE: Check only signal pipe. Used when an external command
 - * is running. During that time curses is disabled.  Returns when
 - * cmd_pid == 0.
 - */
 -static int do_select(int mode)
 -{
 -	fd_set rfds;
 -	int ret, i, max_fileno;
 -	char command_buf[2][COMMAND_BUF_SIZE] = {"", ""};
 -	int cbo[2] = {0, 0}; /* command buf offsets */
 -	struct timeval tv;
 -	unsigned flags[2] = {0, 0}; /* for for_each_line() */
 -
 -repeat:
 -	tv.tv_sec = conf.timeout_arg  / 1000;
 -	tv.tv_usec = (conf.timeout_arg % 1000) * 1000;
 -//	ret = refresh_status();
 -	FD_ZERO(&rfds);
 -	max_fileno = 0;
 -	status_pre_select(&rfds, &max_fileno, &tv);
 -	/* signal pipe */
 -	para_fd_set(signal_pipe, &rfds, &max_fileno);
 -	/* command pipe only for COMMAND_MODE */
 -	if (mode == COMMAND_MODE) {
 -		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);
++static int exec_post_select(struct sched *s, void *context)
 +{
- 	struct exec_task *ct = container_of(t, struct exec_task, task);
++	struct exec_task *ct = context;
 +	int i, ret;
 +
- 	ret = task_get_notification(t);
++	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, " ");
 +		}
  	}
 -	if (mode == GETCH_MODE || mode == COMMAND_MODE)
 -		para_fd_set(STDIN_FILENO, &rfds, &max_fileno);
 -	ret = para_select(max_fileno + 1, &rfds, NULL, &tv);
 -	if (ret <= 0)
 -		goto check_return; /* skip fd checks */
 -	/* signals */
 -	ret = para_next_signal(&rfds);
 -	if (ret > 0)
 -		handle_signal(ret);
 -	/* read command pipe if ready */
 -	if (mode == COMMAND_MODE) {
 -		for (i = 0; i < 2; i++) {
 -			size_t sz;
 -			if (command_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;
 -			}
 -			if (ret < 0) {
 +	for (i = 0; i < 2; i++) {
 +		size_t sz;
 +		if (exec_fds[i] < 0)
 +			continue;
 +		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 || 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;
 -				if (command_fds[!i] < 0) /* both fds closed */
 -					return 0;
 -			}
 -			if (cbo[i] == COMMAND_BUF_SIZE - 1) {
 -				PARA_NOTICE_LOG("discarding overlong line");
 -				cbo[i] = 0;
 -				flags[i] = FELF_DISCARD_FIRST;
 -			}
 +			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;
  		}
 -	}
 -	ret = read_stat_pipe(&rfds);
 -	if (ret < 0) {
 -		PARA_NOTICE_LOG("closing stat pipe: %s\n", para_strerror(-ret));
 -		close(stat_pipe);
 -		stat_pipe = -1;
 -		clear_all_items();
 -		free(stat_content[SI_BASENAME]);
 -		stat_content[SI_BASENAME] =
 -			para_strdup("stat command terminated!?");
 -		print_all_items();
 -	}
 -check_return:
 -	switch (mode) {
 -	case COMMAND_MODE:
 -		ret = wgetch(top.win);
 -		if (ret != ERR && ret != KEY_RESIZE) {
 -			if (command_fds[0] >= 0) {
 -				close(command_fds[0]);
 -				command_fds[0] = -1;
 -			}
 -			if (command_fds[1] >= 0) {
 -				close(command_fds[1]);
 -				command_fds[1] = -1;
 -			}
 -			if (cmd_pid)
 -				kill(cmd_pid, SIGTERM);
 -			return -1;
 +		if (ct->cbo[i] == COMMAND_BUF_SIZE - 1) {
 +			PARA_NOTICE_LOG("discarding overlong line");
 +			ct->cbo[i] = 0;
 +			ct->flags[i] = FELF_DISCARD_FIRST;
  		}
 -		break;
 -	case GETCH_MODE:
 -		ret = wgetch(top.win);
 -		if (ret != ERR && ret != KEY_RESIZE)
 -			return ret;
 -		break;
 -	case EXTERNAL_MODE:
 -		if (cmd_pid == 0)
 -			return 0;
  	}
 -	goto repeat;
 +	return 0;
  }
  
- static void input_pre_select(struct sched *s, __a_unused struct task *t)
 -/*
 - * read from command pipe and print data to bot window
 - */
 -static void send_output(void)
++static void input_pre_select(struct sched *s, __a_unused void *context)
  {
 -	int ret;
 +	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(const char *file_and_args)
 +{
 +	int ret, fds[3] = {0, 1, 1};
  
 -	ret = mark_fd_nonblocking(command_fds[0]);
 +	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]);
  	if (ret < 0)
  		goto fail;
 -	ret = mark_fd_nonblocking(command_fds[1]);
 +	ret = mark_fd_nonblocking(fds[2]);
  	if (ret < 0)
  		goto fail;
 -	if (do_select(COMMAND_MODE) >= 0)
 -		PARA_INFO_LOG("command complete");
 -	else
 -		PARA_NOTICE_LOG("command aborted");
 -	print_in_bar(COLOR_MSG, " ");
 +	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));
@@@ -1036,104 -1147,35 +1037,104 @@@ static void exec_para(const char *args
  }
  
  /*
 - * exec command and print output to bot win
 + * shutdown curses and stat pipe before executing external commands
   */
 -static void display_cmd(char *cmd)
 +static void exec_external(char *file_and_args)
  {
 -	int fds[3] = {0, 1, 1};
 +	int fds[3] = {-1, -1, -1};
  
 -	print_in_bar(COLOR_MSG, "executing display command, hit any key to abort");
 -	outputf(COLOR_COMMAND, "%s", cmd);
 -	if (para_exec_cmdline_pid(&cmd_pid, cmd, fds) < 0)
 +	if (exec_pid)
  		return;
 -	command_fds[0] = fds[1];
 -	command_fds[1] = fds[2];
 -	send_output();
 +	shutdown_curses();
 +	para_exec_cmdline_pid(&exec_pid, file_and_args, fds);
  }
  
 -/*
 - * shutdown curses and stat pipe before executing external commands
 - */
 -static void external_cmd(char *cmd)
 +static void handle_command(int c)
  {
 -	int fds[3] = {-1, -1, -1};
 +	int i;
  
 -	if (cmd_pid)
 -		return;
 -	shutdown_curses();
 -	if (para_exec_cmdline_pid(&cmd_pid, cmd, fds) < 0)
 +	/* first check user-defined key bindings */
 +	for (i = 0; i < conf.key_map_given; ++i) {
 +		char *tmp, *handler, *arg;
 +
 +		tmp = para_strdup(conf.key_map_arg[i]);
 +		if (!split_key_map(tmp, &handler, &arg)) {
 +			free(tmp);
 +			return;
 +		}
 +		if (strcmp(tmp, km_keyname(c))) {
 +			free(tmp);
 +			continue;
 +		}
 +		if (*handler == 'd')
 +			exec_and_display(arg);
 +		else if (*handler == 'x')
 +			exec_external(arg);
 +		else if (*handler == 'p')
 +			exec_para(arg);
 +		else if (*handler == 'i') {
 +			int num = find_cmd_byname(arg);
 +			if (num >= 0)
 +				command_list[num].handler();
 +		}
 +		free(tmp);
  		return;
 -	do_select(EXTERNAL_MODE);
 -	init_curses();
 +	}
 +	/* not found, check internal key bindings */
 +	for (i = 0; command_list[i].handler; i++) {
 +		if (!strcmp(km_keyname(c), command_list[i].key)) {
 +			command_list[i].handler();
 +			return;
 +		}
 +	}
 +	print_in_bar(COLOR_ERRMSG, "key '%s' is not bound, press ? for help",
 +		km_keyname(c));
 +}
 +
- static int input_post_select(__a_unused struct sched *s, __a_unused struct task *t)
++static int input_post_select(__a_unused struct sched *s, __a_unused void *context)
 +{
 +	int ret;
 +	enum exec_status exs = exec_status();
 +
 +	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)
 +		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 signal_pre_select(struct sched *s, struct task *t)
++static void signal_pre_select(struct sched *s, void *context)
 +{
- 	struct signal_task *st = container_of(t, struct signal_task, task);
++	struct signal_task *st = context;
 +	para_fd_set(st->fd, &s->rfds, &s->max_fileno);
  }
  
  static void print_scroll_msg(void)
@@@ -1404,83 -1519,14 +1405,81 @@@ __noreturn static void print_help_and_d
  	exit(0);
  }
  
 -int main(int argc, char *argv[])
 +static int setup_tasks_and_schedule(void)
  {
 -	int ret;
 -	char *cf;
++	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 = {.task = NULL};
 +	struct sched sched = {
 +		.default_timeout = {
 +			.tv_sec = conf.timeout_arg  / 1000,
 +			.tv_usec = (conf.timeout_arg % 1000) * 1000,
 +		},
 +	};
- 	struct exec_task exec_task = {
- 		.task = {
- 			.status = "exec",
- 			.pre_select = exec_pre_select,
- 			.post_select = exec_post_select,
- 		},
- 	};
- 	struct status_task status_task = {
- 		.task = {
- 			.status = "status",
- 			.pre_select = status_pre_select,
- 			.post_select = status_post_select,
- 		},
- 		.fd = -1
- 	};
- 	struct input_task input_task = {
- 		.task = {
- 			.status = "input",
- 			.pre_select = input_pre_select,
- 			.post_select = input_post_select,
- 		},
- 	};
- 	struct signal_task signal_task = {
- 		.task = {
- 			.status = "signal",
- 			.pre_select = signal_pre_select,
- 			.post_select = signal_post_select,
- 		},
- 	};
+ 
 -	_argc = argc;
 -	_argv = argv;
++	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.fd = para_signal_init();
 +	para_install_sighandler(SIGINT);
 +	para_install_sighandler(SIGTERM);
 +	para_install_sighandler(SIGCHLD);
 +	para_install_sighandler(SIGUSR1);
- 
- 	register_task(&sched, &exec_task.task);
- 	register_task(&sched, &status_task.task);
- 	register_task(&sched, &input_task.task);
- 	register_task(&sched, &signal_task.task);
++	signal_task.task = task_register(&(struct task_info) {
++		.name = "signal",
++		.pre_select = signal_pre_select,
++		.post_select = signal_post_select,
++		.context = &signal_task,
++	}, &sched);
 +	return schedule(&sched);
 +}
  
 +/**
 + * 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 */
  	loglevel = get_loglevel_by_name(conf.loglevel_arg);
  	version_handle_flag("gui", conf.version_given);
diff --cc server.c
index fa19ce42,bcbf2404..908e039b
--- a/server.c
+++ b/server.c
@@@ -484,9 -488,9 +488,7 @@@ static void server_init(int argc, char 
  	parse_config_or_die(0);
  	log_welcome("para_server");
  	init_ipc_or_die(); /* init mmd struct and mmd->lock */
--	/* make sure, the global now pointer is uptodate */
--	clock_get_realtime(now);
--	set_server_start_time(now);
++	set_server_start_time(NULL);
  	init_user_list(user_list_file);
  	/* become daemon */
  	if (conf.daemon_given)