xref: /openbsd-src/usr.bin/tmux/cmd-queue.c (revision 5a38ef86d0b61900239c7913d24a05e7b88a58f0)
1 /* $OpenBSD: cmd-queue.c,v 1.107 2021/08/21 17:25:32 nicm Exp $ */
2 
3 /*
4  * Copyright (c) 2013 Nicholas Marriott <nicholas.marriott@gmail.com>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
15  * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
16  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 #include <sys/types.h>
20 
21 #include <ctype.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <time.h>
25 
26 #include "tmux.h"
27 
28 /* Command queue flags. */
29 #define CMDQ_FIRED 0x1
30 #define CMDQ_WAITING 0x2
31 
32 /* Command queue item type. */
33 enum cmdq_type {
34 	CMDQ_COMMAND,
35 	CMDQ_CALLBACK,
36 };
37 
38 /* Command queue item. */
39 struct cmdq_item {
40 	char			*name;
41 	struct cmdq_list	*queue;
42 	struct cmdq_item	*next;
43 
44 	struct client		*client;
45 	struct client		*target_client;
46 
47 	enum cmdq_type		 type;
48 	u_int			 group;
49 
50 	u_int			 number;
51 	time_t			 time;
52 
53 	int			 flags;
54 
55 	struct cmdq_state	*state;
56 	struct cmd_find_state	 source;
57 	struct cmd_find_state	 target;
58 
59 	struct cmd_list		*cmdlist;
60 	struct cmd		*cmd;
61 
62 	cmdq_cb			 cb;
63 	void			*data;
64 
65 	TAILQ_ENTRY(cmdq_item)	 entry;
66 };
67 TAILQ_HEAD(cmdq_item_list, cmdq_item);
68 
69 /*
70  * Command queue state. This is the context for commands on the command queue.
71  * It holds information about how the commands were fired (the key and flags),
72  * any additional formats for the commands, and the current default target.
73  * Multiple commands can share the same state and a command may update the
74  * default target.
75  */
76 struct cmdq_state {
77 	int			 references;
78 	int			 flags;
79 
80 	struct format_tree	*formats;
81 
82 	struct key_event	 event;
83 	struct cmd_find_state	 current;
84 };
85 
86 /* Command queue. */
87 struct cmdq_list {
88 	struct cmdq_item	*item;
89 	struct cmdq_item_list	 list;
90 };
91 
92 /* Get command queue name. */
93 static const char *
94 cmdq_name(struct client *c)
95 {
96 	static char	s[256];
97 
98 	if (c == NULL)
99 		return ("<global>");
100 	if (c->name != NULL)
101 		xsnprintf(s, sizeof s, "<%s>", c->name);
102 	else
103 		xsnprintf(s, sizeof s, "<%p>", c);
104 	return (s);
105 }
106 
107 /* Get command queue from client. */
108 static struct cmdq_list *
109 cmdq_get(struct client *c)
110 {
111 	static struct cmdq_list *global_queue;
112 
113 	if (c == NULL) {
114 		if (global_queue == NULL)
115 			global_queue = cmdq_new();
116 		return (global_queue);
117 	}
118 	return (c->queue);
119 }
120 
121 /* Create a queue. */
122 struct cmdq_list *
123 cmdq_new(void)
124 {
125 	struct cmdq_list	*queue;
126 
127 	queue = xcalloc (1, sizeof *queue);
128 	TAILQ_INIT (&queue->list);
129 	return (queue);
130 }
131 
132 /* Free a queue. */
133 void
134 cmdq_free(struct cmdq_list *queue)
135 {
136 	if (!TAILQ_EMPTY(&queue->list))
137 		fatalx("queue not empty");
138 	free(queue);
139 }
140 
141 /* Get item name. */
142 const char *
143 cmdq_get_name(struct cmdq_item *item)
144 {
145 	return (item->name);
146 }
147 
148 /* Get item client. */
149 struct client *
150 cmdq_get_client(struct cmdq_item *item)
151 {
152 	return (item->client);
153 }
154 
155 /* Get item target client. */
156 struct client *
157 cmdq_get_target_client(struct cmdq_item *item)
158 {
159 	return (item->target_client);
160 }
161 
162 /* Get item state. */
163 struct cmdq_state *
164 cmdq_get_state(struct cmdq_item *item)
165 {
166 	return (item->state);
167 }
168 
169 /* Get item target. */
170 struct cmd_find_state *
171 cmdq_get_target(struct cmdq_item *item)
172 {
173 	return (&item->target);
174 }
175 
176 /* Get item source. */
177 struct cmd_find_state *
178 cmdq_get_source(struct cmdq_item *item)
179 {
180 	return (&item->source);
181 }
182 
183 /* Get state event. */
184 struct key_event *
185 cmdq_get_event(struct cmdq_item *item)
186 {
187 	return (&item->state->event);
188 }
189 
190 /* Get state current target. */
191 struct cmd_find_state *
192 cmdq_get_current(struct cmdq_item *item)
193 {
194 	return (&item->state->current);
195 }
196 
197 /* Get state flags. */
198 int
199 cmdq_get_flags(struct cmdq_item *item)
200 {
201 	return (item->state->flags);
202 }
203 
204 /* Create a new state. */
205 struct cmdq_state *
206 cmdq_new_state(struct cmd_find_state *current, struct key_event *event,
207     int flags)
208 {
209 	struct cmdq_state	*state;
210 
211 	state = xcalloc(1, sizeof *state);
212 	state->references = 1;
213 	state->flags = flags;
214 
215 	if (event != NULL)
216 		memcpy(&state->event, event, sizeof state->event);
217 	else
218 		state->event.key = KEYC_NONE;
219 	if (current != NULL && cmd_find_valid_state(current))
220 		cmd_find_copy_state(&state->current, current);
221 	else
222 		cmd_find_clear_state(&state->current, 0);
223 
224 	return (state);
225 }
226 
227 /* Add a reference to a state. */
228 struct cmdq_state *
229 cmdq_link_state(struct cmdq_state *state)
230 {
231 	state->references++;
232 	return (state);
233 }
234 
235 /* Make a copy of a state. */
236 struct cmdq_state *
237 cmdq_copy_state(struct cmdq_state *state)
238 {
239 	return (cmdq_new_state(&state->current, &state->event, state->flags));
240 }
241 
242 /* Free a state. */
243 void
244 cmdq_free_state(struct cmdq_state *state)
245 {
246 	if (--state->references != 0)
247 		return;
248 
249 	if (state->formats != NULL)
250 		format_free(state->formats);
251 	free(state);
252 }
253 
254 /* Add a format to command queue. */
255 void
256 cmdq_add_format(struct cmdq_state *state, const char *key, const char *fmt, ...)
257 {
258 	va_list	 ap;
259 	char	*value;
260 
261 	va_start(ap, fmt);
262 	xvasprintf(&value, fmt, ap);
263 	va_end(ap);
264 
265 	if (state->formats == NULL)
266 		state->formats = format_create(NULL, NULL, FORMAT_NONE, 0);
267 	format_add(state->formats, key, "%s", value);
268 
269 	free(value);
270 }
271 
272 /* Add formats to command queue. */
273 void
274 cmdq_add_formats(struct cmdq_state *state, struct format_tree *ft)
275 {
276 	if (state->formats == NULL)
277 		state->formats = format_create(NULL, NULL, FORMAT_NONE, 0);
278 	format_merge(state->formats, ft);
279 }
280 
281 /* Merge formats from item. */
282 void
283 cmdq_merge_formats(struct cmdq_item *item, struct format_tree *ft)
284 {
285 	const struct cmd_entry	*entry;
286 
287 	if (item->cmd != NULL) {
288 		entry = cmd_get_entry(item->cmd);
289 		format_add(ft, "command", "%s", entry->name);
290 	}
291 	if (item->state->formats != NULL)
292 		format_merge(ft, item->state->formats);
293 }
294 
295 /* Append an item. */
296 struct cmdq_item *
297 cmdq_append(struct client *c, struct cmdq_item *item)
298 {
299 	struct cmdq_list	*queue = cmdq_get(c);
300 	struct cmdq_item	*next;
301 
302 	do {
303 		next = item->next;
304 		item->next = NULL;
305 
306 		if (c != NULL)
307 			c->references++;
308 		item->client = c;
309 
310 		item->queue = queue;
311 		TAILQ_INSERT_TAIL(&queue->list, item, entry);
312 		log_debug("%s %s: %s", __func__, cmdq_name(c), item->name);
313 
314 		item = next;
315 	} while (item != NULL);
316 	return (TAILQ_LAST(&queue->list, cmdq_item_list));
317 }
318 
319 /* Insert an item. */
320 struct cmdq_item *
321 cmdq_insert_after(struct cmdq_item *after, struct cmdq_item *item)
322 {
323 	struct client		*c = after->client;
324 	struct cmdq_list	*queue = after->queue;
325 	struct cmdq_item	*next;
326 
327 	do {
328 		next = item->next;
329 		item->next = after->next;
330 		after->next = item;
331 
332 		if (c != NULL)
333 			c->references++;
334 		item->client = c;
335 
336 		item->queue = queue;
337 		TAILQ_INSERT_AFTER(&queue->list, after, item, entry);
338 		log_debug("%s %s: %s after %s", __func__, cmdq_name(c),
339 		    item->name, after->name);
340 
341 		after = item;
342 		item = next;
343 	} while (item != NULL);
344 	return (after);
345 }
346 
347 /* Insert a hook. */
348 void
349 cmdq_insert_hook(struct session *s, struct cmdq_item *item,
350     struct cmd_find_state *current, const char *fmt, ...)
351 {
352 	struct cmdq_state		*state = item->state;
353 	struct cmd			*cmd = item->cmd;
354 	struct args			*args = cmd_get_args(cmd);
355 	struct args_entry		*ae;
356 	struct args_value		*av;
357 	struct options			*oo;
358 	va_list				 ap;
359 	char				*name, tmp[32], flag, *arguments;
360 	u_int				 i;
361 	const char			*value;
362 	struct cmdq_item		*new_item;
363 	struct cmdq_state		*new_state;
364 	struct options_entry		*o;
365 	struct options_array_item	*a;
366 	struct cmd_list			*cmdlist;
367 
368 	if (item->state->flags & CMDQ_STATE_NOHOOKS)
369 		return;
370 	if (s == NULL)
371 		oo = global_s_options;
372 	else
373 		oo = s->options;
374 
375 	va_start(ap, fmt);
376 	xvasprintf(&name, fmt, ap);
377 	va_end(ap);
378 
379 	o = options_get(oo, name);
380 	if (o == NULL) {
381 		free(name);
382 		return;
383 	}
384 	log_debug("running hook %s (parent %p)", name, item);
385 
386 	/*
387 	 * The hooks get a new state because they should not update the current
388 	 * target or formats for any subsequent commands.
389 	 */
390 	new_state = cmdq_new_state(current, &state->event, CMDQ_STATE_NOHOOKS);
391 	cmdq_add_format(new_state, "hook", "%s", name);
392 
393 	arguments = args_print(args);
394 	cmdq_add_format(new_state, "hook_arguments", "%s", arguments);
395 	free(arguments);
396 
397 	for (i = 0; i < args_count(args); i++) {
398 		xsnprintf(tmp, sizeof tmp, "hook_argument_%d", i);
399 		cmdq_add_format(new_state, tmp, "%s", args_string(args, i));
400 	}
401 	flag = args_first(args, &ae);
402 	while (flag != 0) {
403 		value = args_get(args, flag);
404 		if (value == NULL) {
405 			xsnprintf(tmp, sizeof tmp, "hook_flag_%c", flag);
406 			cmdq_add_format(new_state, tmp, "1");
407 		} else {
408 			xsnprintf(tmp, sizeof tmp, "hook_flag_%c", flag);
409 			cmdq_add_format(new_state, tmp, "%s", value);
410 		}
411 
412 		i = 0;
413 		av = args_first_value(args, flag);
414 		while (av != NULL) {
415 			xsnprintf(tmp, sizeof tmp, "hook_flag_%c_%d", flag, i);
416 			cmdq_add_format(new_state, tmp, "%s", av->string);
417 			i++;
418 			av = args_next_value(av);
419 		}
420 
421 		flag = args_next(&ae);
422 	}
423 
424 	a = options_array_first(o);
425 	while (a != NULL) {
426 		cmdlist = options_array_item_value(a)->cmdlist;
427 		if (cmdlist != NULL) {
428 			new_item = cmdq_get_command(cmdlist, new_state);
429 			if (item != NULL)
430 				item = cmdq_insert_after(item, new_item);
431 			else
432 				item = cmdq_append(NULL, new_item);
433 		}
434 		a = options_array_next(a);
435 	}
436 
437 	cmdq_free_state(new_state);
438 	free(name);
439 }
440 
441 /* Continue processing command queue. */
442 void
443 cmdq_continue(struct cmdq_item *item)
444 {
445 	item->flags &= ~CMDQ_WAITING;
446 }
447 
448 /* Remove an item. */
449 static void
450 cmdq_remove(struct cmdq_item *item)
451 {
452 	if (item->client != NULL)
453 		server_client_unref(item->client);
454 	if (item->cmdlist != NULL)
455 		cmd_list_free(item->cmdlist);
456 	cmdq_free_state(item->state);
457 
458 	TAILQ_REMOVE(&item->queue->list, item, entry);
459 
460 	free(item->name);
461 	free(item);
462 }
463 
464 /* Remove all subsequent items that match this item's group. */
465 static void
466 cmdq_remove_group(struct cmdq_item *item)
467 {
468 	struct cmdq_item	*this, *next;
469 
470 	if (item->group == 0)
471 		return;
472 	this = TAILQ_NEXT(item, entry);
473 	while (this != NULL) {
474 		next = TAILQ_NEXT(this, entry);
475 		if (this->group == item->group)
476 			cmdq_remove(this);
477 		this = next;
478 	}
479 }
480 
481 /* Empty command callback. */
482 static enum cmd_retval
483 cmdq_empty_command(__unused struct cmdq_item *item, __unused void *data)
484 {
485 	return (CMD_RETURN_NORMAL);
486 }
487 
488 /* Get a command for the command queue. */
489 struct cmdq_item *
490 cmdq_get_command(struct cmd_list *cmdlist, struct cmdq_state *state)
491 {
492 	struct cmdq_item	*item, *first = NULL, *last = NULL;
493 	struct cmd		*cmd;
494 	const struct cmd_entry	*entry;
495 	int			 created = 0;
496 
497 	if ((cmd = cmd_list_first(cmdlist)) == NULL)
498 		return (cmdq_get_callback(cmdq_empty_command, NULL));
499 
500 	if (state == NULL) {
501 		state = cmdq_new_state(NULL, NULL, 0);
502 		created = 1;
503 	}
504 
505 	while (cmd != NULL) {
506 		entry = cmd_get_entry(cmd);
507 
508 		item = xcalloc(1, sizeof *item);
509 		xasprintf(&item->name, "[%s/%p]", entry->name, item);
510 		item->type = CMDQ_COMMAND;
511 
512 		item->group = cmd_get_group(cmd);
513 		item->state = cmdq_link_state(state);
514 
515 		item->cmdlist = cmdlist;
516 		item->cmd = cmd;
517 
518 		cmdlist->references++;
519 		log_debug("%s: %s group %u", __func__, item->name, item->group);
520 
521 		if (first == NULL)
522 			first = item;
523 		if (last != NULL)
524 			last->next = item;
525 		last = item;
526 
527 		cmd = cmd_list_next(cmd);
528 	}
529 
530 	if (created)
531 		cmdq_free_state(state);
532 	return (first);
533 }
534 
535 /* Fill in flag for a command. */
536 static enum cmd_retval
537 cmdq_find_flag(struct cmdq_item *item, struct cmd_find_state *fs,
538     const struct cmd_entry_flag *flag)
539 {
540 	const char	*value;
541 
542 	if (flag->flag == 0) {
543 		cmd_find_from_client(fs, item->target_client, 0);
544 		return (CMD_RETURN_NORMAL);
545 	}
546 
547 	value = args_get(cmd_get_args(item->cmd), flag->flag);
548 	if (cmd_find_target(fs, item, value, flag->type, flag->flags) != 0) {
549 		cmd_find_clear_state(fs, 0);
550 		return (CMD_RETURN_ERROR);
551 	}
552 	return (CMD_RETURN_NORMAL);
553 }
554 
555 /* Add message with command. */
556 static void
557 cmdq_add_message(struct cmdq_item *item)
558 {
559 	struct client		*c = item->client;
560 	struct cmdq_state	*state = item->state;
561 	const char		*name, *key;
562 	char			*tmp;
563 
564 	tmp = cmd_print(item->cmd);
565 	if (c != NULL) {
566 		name = c->name;
567 		if (c->session != NULL && state->event.key != KEYC_NONE) {
568 			key = key_string_lookup_key(state->event.key, 0);
569 			server_add_message("%s key %s: %s", name, key, tmp);
570 		} else
571 			server_add_message("%s command: %s", name, tmp);
572 	} else
573 		server_add_message("command: %s", tmp);
574 	free(tmp);
575 }
576 
577 /* Fire command on command queue. */
578 static enum cmd_retval
579 cmdq_fire_command(struct cmdq_item *item)
580 {
581 	const char		*name = cmdq_name(item->client);
582 	struct cmdq_state	*state = item->state;
583 	struct cmd		*cmd = item->cmd;
584 	struct args		*args = cmd_get_args(cmd);
585 	const struct cmd_entry	*entry = cmd_get_entry(cmd);
586 	struct client		*tc, *saved = item->client;
587 	enum cmd_retval		 retval;
588 	struct cmd_find_state	*fsp, fs;
589 	int			 flags, quiet = 0;
590 	char			*tmp;
591 
592 	if (cfg_finished)
593 		cmdq_add_message(item);
594 	if (log_get_level() > 1) {
595 		tmp = cmd_print(cmd);
596 		log_debug("%s %s: (%u) %s", __func__, name, item->group, tmp);
597 		free(tmp);
598 	}
599 
600 	flags = !!(state->flags & CMDQ_STATE_CONTROL);
601 	cmdq_guard(item, "begin", flags);
602 
603 	if (item->client == NULL)
604 		item->client = cmd_find_client(item, NULL, 1);
605 
606 	if (entry->flags & CMD_CLIENT_CANFAIL)
607 		quiet = 1;
608 	if (entry->flags & CMD_CLIENT_CFLAG) {
609 		tc = cmd_find_client(item, args_get(args, 'c'), quiet);
610 		if (tc == NULL && !quiet) {
611 			retval = CMD_RETURN_ERROR;
612 			goto out;
613 		}
614 	} else if (entry->flags & CMD_CLIENT_TFLAG) {
615 		tc = cmd_find_client(item, args_get(args, 't'), quiet);
616 		if (tc == NULL && !quiet) {
617 			retval = CMD_RETURN_ERROR;
618 			goto out;
619 		}
620 	} else
621 		tc = cmd_find_client(item, NULL, 1);
622 	item->target_client = tc;
623 
624 	retval = cmdq_find_flag(item, &item->source, &entry->source);
625 	if (retval == CMD_RETURN_ERROR)
626 		goto out;
627 	retval = cmdq_find_flag(item, &item->target, &entry->target);
628 	if (retval == CMD_RETURN_ERROR)
629 		goto out;
630 
631 	retval = entry->exec(cmd, item);
632 	if (retval == CMD_RETURN_ERROR)
633 		goto out;
634 
635 	if (entry->flags & CMD_AFTERHOOK) {
636 		if (cmd_find_valid_state(&item->target))
637 			fsp = &item->target;
638 		else if (cmd_find_valid_state(&item->state->current))
639 			fsp = &item->state->current;
640 		else if (cmd_find_from_client(&fs, item->client, 0) == 0)
641 			fsp = &fs;
642 		else
643 			goto out;
644 		cmdq_insert_hook(fsp->s, item, fsp, "after-%s", entry->name);
645 	}
646 
647 out:
648 	item->client = saved;
649 	if (retval == CMD_RETURN_ERROR)
650 		cmdq_guard(item, "error", flags);
651 	else
652 		cmdq_guard(item, "end", flags);
653 	return (retval);
654 }
655 
656 /* Get a callback for the command queue. */
657 struct cmdq_item *
658 cmdq_get_callback1(const char *name, cmdq_cb cb, void *data)
659 {
660 	struct cmdq_item	*item;
661 
662 	item = xcalloc(1, sizeof *item);
663 	xasprintf(&item->name, "[%s/%p]", name, item);
664 	item->type = CMDQ_CALLBACK;
665 
666 	item->group = 0;
667 	item->state = cmdq_new_state(NULL, NULL, 0);
668 
669 	item->cb = cb;
670 	item->data = data;
671 
672 	return (item);
673 }
674 
675 /* Generic error callback. */
676 static enum cmd_retval
677 cmdq_error_callback(struct cmdq_item *item, void *data)
678 {
679 	char	*error = data;
680 
681 	cmdq_error(item, "%s", error);
682 	free(error);
683 
684 	return (CMD_RETURN_NORMAL);
685 }
686 
687 /* Get an error callback for the command queue. */
688 struct cmdq_item *
689 cmdq_get_error(const char *error)
690 {
691 	return (cmdq_get_callback(cmdq_error_callback, xstrdup(error)));
692 }
693 
694 /* Fire callback on callback queue. */
695 static enum cmd_retval
696 cmdq_fire_callback(struct cmdq_item *item)
697 {
698 	return (item->cb(item, item->data));
699 }
700 
701 /* Process next item on command queue. */
702 u_int
703 cmdq_next(struct client *c)
704 {
705 	struct cmdq_list	*queue = cmdq_get(c);
706 	const char		*name = cmdq_name(c);
707 	struct cmdq_item	*item;
708 	enum cmd_retval		 retval;
709 	u_int			 items = 0;
710 	static u_int		 number;
711 
712 	if (TAILQ_EMPTY(&queue->list)) {
713 		log_debug("%s %s: empty", __func__, name);
714 		return (0);
715 	}
716 	if (TAILQ_FIRST(&queue->list)->flags & CMDQ_WAITING) {
717 		log_debug("%s %s: waiting", __func__, name);
718 		return (0);
719 	}
720 
721 	log_debug("%s %s: enter", __func__, name);
722 	for (;;) {
723 		item = queue->item = TAILQ_FIRST(&queue->list);
724 		if (item == NULL)
725 			break;
726 		log_debug("%s %s: %s (%d), flags %x", __func__, name,
727 		    item->name, item->type, item->flags);
728 
729 		/*
730 		 * Any item with the waiting flag set waits until an external
731 		 * event clears the flag (for example, a job - look at
732 		 * run-shell).
733 		 */
734 		if (item->flags & CMDQ_WAITING)
735 			goto waiting;
736 
737 		/*
738 		 * Items are only fired once, once the fired flag is set, a
739 		 * waiting flag can only be cleared by an external event.
740 		 */
741 		if (~item->flags & CMDQ_FIRED) {
742 			item->time = time(NULL);
743 			item->number = ++number;
744 
745 			switch (item->type) {
746 			case CMDQ_COMMAND:
747 				retval = cmdq_fire_command(item);
748 
749 				/*
750 				 * If a command returns an error, remove any
751 				 * subsequent commands in the same group.
752 				 */
753 				if (retval == CMD_RETURN_ERROR)
754 					cmdq_remove_group(item);
755 				break;
756 			case CMDQ_CALLBACK:
757 				retval = cmdq_fire_callback(item);
758 				break;
759 			default:
760 				retval = CMD_RETURN_ERROR;
761 				break;
762 			}
763 			item->flags |= CMDQ_FIRED;
764 
765 			if (retval == CMD_RETURN_WAIT) {
766 				item->flags |= CMDQ_WAITING;
767 				goto waiting;
768 			}
769 			items++;
770 		}
771 		cmdq_remove(item);
772 	}
773 	queue->item = NULL;
774 
775 	log_debug("%s %s: exit (empty)", __func__, name);
776 	return (items);
777 
778 waiting:
779 	log_debug("%s %s: exit (wait)", __func__, name);
780 	return (items);
781 }
782 
783 /* Get running item if any. */
784 struct cmdq_item *
785 cmdq_running(struct client *c)
786 {
787 	struct cmdq_list	*queue = cmdq_get(c);
788 
789 	if (queue->item == NULL)
790         return (NULL);
791     if (queue->item->flags & CMDQ_WAITING)
792         return (NULL);
793     return (queue->item);
794 }
795 
796 /* Print a guard line. */
797 void
798 cmdq_guard(struct cmdq_item *item, const char *guard, int flags)
799 {
800 	struct client	*c = item->client;
801 	long		 t = item->time;
802 	u_int		 number = item->number;
803 
804 	if (c != NULL && (c->flags & CLIENT_CONTROL))
805 		control_write(c, "%%%s %ld %u %d", guard, t, number, flags);
806 }
807 
808 /* Show message from command. */
809 void
810 cmdq_print(struct cmdq_item *item, const char *fmt, ...)
811 {
812 	struct client			*c = item->client;
813 	struct window_pane		*wp;
814 	struct window_mode_entry	*wme;
815 	va_list				 ap;
816 	char				*tmp, *msg;
817 
818 	va_start(ap, fmt);
819 	xvasprintf(&msg, fmt, ap);
820 	va_end(ap);
821 
822 	log_debug("%s: %s", __func__, msg);
823 
824 	if (c == NULL)
825 		/* nothing */;
826 	else if (c->session == NULL || (c->flags & CLIENT_CONTROL)) {
827 		if (~c->flags & CLIENT_UTF8) {
828 			tmp = msg;
829 			msg = utf8_sanitize(tmp);
830 			free(tmp);
831 		}
832 		if (c->flags & CLIENT_CONTROL)
833 			control_write(c, "%s", msg);
834 		else
835 			file_print(c, "%s\n", msg);
836 	} else {
837 		wp = server_client_get_pane(c);
838 		wme = TAILQ_FIRST(&wp->modes);
839 		if (wme == NULL || wme->mode != &window_view_mode) {
840 			window_pane_set_mode(wp, NULL, &window_view_mode, NULL,
841 			    NULL);
842 		}
843 		window_copy_add(wp, "%s", msg);
844 	}
845 
846 	free(msg);
847 }
848 
849 /* Show error from command. */
850 void
851 cmdq_error(struct cmdq_item *item, const char *fmt, ...)
852 {
853 	struct client	*c = item->client;
854 	struct cmd	*cmd = item->cmd;
855 	va_list		 ap;
856 	char		*msg, *tmp;
857 	const char	*file;
858 	u_int		 line;
859 
860 	va_start(ap, fmt);
861 	xvasprintf(&msg, fmt, ap);
862 	va_end(ap);
863 
864 	log_debug("%s: %s", __func__, msg);
865 
866 	if (c == NULL) {
867 		cmd_get_source(cmd, &file, &line);
868 		cfg_add_cause("%s:%u: %s", file, line, msg);
869 	} else if (c->session == NULL || (c->flags & CLIENT_CONTROL)) {
870 		server_add_message("%s message: %s", c->name, msg);
871 		if (~c->flags & CLIENT_UTF8) {
872 			tmp = msg;
873 			msg = utf8_sanitize(tmp);
874 			free(tmp);
875 		}
876 		if (c->flags & CLIENT_CONTROL)
877 			control_write(c, "%s", msg);
878 		else
879 			file_error(c, "%s\n", msg);
880 		c->retval = 1;
881 	} else {
882 		*msg = toupper((u_char) *msg);
883 		status_message_set(c, -1, 1, 0, "%s", msg);
884 	}
885 
886 	free(msg);
887 }
888