xref: /openbsd-src/usr.bin/tmux/arguments.c (revision 5a38ef86d0b61900239c7913d24a05e7b88a58f0)
1 /* $OpenBSD: arguments.c,v 1.52 2021/11/02 10:57:04 nicm Exp $ */
2 
3 /*
4  * Copyright (c) 2010 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 <vis.h>
25 
26 #include "tmux.h"
27 
28 /*
29  * Manipulate command arguments.
30  */
31 
32 /* List of argument values. */
33 TAILQ_HEAD(args_values, args_value);
34 
35 /* Single arguments flag. */
36 struct args_entry {
37 	u_char			 flag;
38 	struct args_values	 values;
39 	u_int			 count;
40 	RB_ENTRY(args_entry)	 entry;
41 };
42 
43 /* Parsed argument flags and values. */
44 struct args {
45 	struct args_tree	 tree;
46 	u_int			 count;
47 	struct args_value	*values;
48 };
49 
50 /* Prepared command state. */
51 struct args_command_state {
52 	struct cmd_list		*cmdlist;
53 	char			*cmd;
54 	struct cmd_parse_input	 pi;
55 };
56 
57 static struct args_entry	*args_find(struct args *, u_char);
58 
59 static int	args_cmp(struct args_entry *, struct args_entry *);
60 RB_GENERATE_STATIC(args_tree, args_entry, entry, args_cmp);
61 
62 /* Arguments tree comparison function. */
63 static int
64 args_cmp(struct args_entry *a1, struct args_entry *a2)
65 {
66 	return (a1->flag - a2->flag);
67 }
68 
69 /* Find a flag in the arguments tree. */
70 static struct args_entry *
71 args_find(struct args *args, u_char flag)
72 {
73 	struct args_entry	entry;
74 
75 	entry.flag = flag;
76 	return (RB_FIND(args_tree, &args->tree, &entry));
77 }
78 
79 /* Copy value. */
80 static void
81 args_copy_value(struct args_value *to, struct args_value *from)
82 {
83 	to->type = from->type;
84 	switch (from->type) {
85 	case ARGS_NONE:
86 		break;
87 	case ARGS_COMMANDS:
88 		to->cmdlist = from->cmdlist;
89 		to->cmdlist->references++;
90 		break;
91 	case ARGS_STRING:
92 		to->string = xstrdup(from->string);
93 		break;
94 	}
95 }
96 
97 /* Get value as string. */
98 static const char *
99 args_value_as_string(struct args_value *value)
100 {
101 	switch (value->type) {
102 	case ARGS_NONE:
103 		return ("");
104 	case ARGS_COMMANDS:
105 		if (value->cached == NULL)
106 			value->cached = cmd_list_print(value->cmdlist, 0);
107 		return (value->cached);
108 	case ARGS_STRING:
109 		return (value->string);
110 	}
111 	fatalx("unexpected argument type");
112 }
113 
114 /* Create an empty arguments set. */
115 struct args *
116 args_create(void)
117 {
118 	struct args	 *args;
119 
120 	args = xcalloc(1, sizeof *args);
121 	RB_INIT(&args->tree);
122 	return (args);
123 }
124 
125 /* Parse arguments into a new argument set. */
126 struct args *
127 args_parse(const struct args_parse *parse, struct args_value *values,
128     u_int count, char **cause)
129 {
130 	struct args		*args;
131 	u_int			 i;
132 	enum args_parse_type	 type;
133 	struct args_value	*value, *new;
134 	u_char			 flag, argument;
135 	const char		*found, *string, *s;
136 
137 	if (count == 0)
138 		return (args_create());
139 
140 	args = args_create();
141 	for (i = 1; i < count; /* nothing */) {
142 		value = &values[i];
143 		if (value->type != ARGS_STRING)
144 			break;
145 
146 		string = value->string;
147 		if (*string++ != '-' || *string == '\0')
148 			break;
149 		i++;
150 		if (string[0] == '-' && string[1] == '\0')
151 			break;
152 
153 		for (;;) {
154 			flag = *string++;
155 			if (flag == '\0')
156 				break;
157 			if (flag == '?') {
158 				args_free(args);
159 				return (NULL);
160 			}
161 			if (!isalnum(flag)) {
162 				xasprintf(cause, "invalid flag -%c", flag);
163 				args_free(args);
164 				return (NULL);
165 			}
166 			found = strchr(parse->template, flag);
167 			if (found == NULL) {
168 				xasprintf(cause, "unknown flag -%c", flag);
169 				args_free(args);
170 				return (NULL);
171 			}
172 			argument = *++found;
173 			if (argument != ':') {
174 				log_debug("%s: -%c", __func__, flag);
175 				args_set(args, flag, NULL);
176 				continue;
177 			}
178 			new = xcalloc(1, sizeof *new);
179 			if (*string != '\0') {
180 				new->type = ARGS_STRING;
181 				new->string = xstrdup(string);
182 			} else {
183 				if (i == count) {
184 					xasprintf(cause,
185 					    "-%c expects an argument",
186 					    flag);
187 					args_free(args);
188 					return (NULL);
189 				}
190 				if (values[i].type != ARGS_STRING) {
191 					xasprintf(cause,
192 					    "-%c argument must be a string",
193 					    flag);
194 					args_free(args);
195 					return (NULL);
196 				}
197 				args_copy_value(new, &values[i++]);
198 			}
199 			s = args_value_as_string(new);
200 			log_debug("%s: -%c = %s", __func__, flag, s);
201 			args_set(args, flag, new);
202 			break;
203 		}
204 	}
205 	log_debug("%s: flags end at %u of %u", __func__, i, count);
206 	if (i != count) {
207 		for (/* nothing */; i < count; i++) {
208 			value = &values[i];
209 
210 			s = args_value_as_string(value);
211 			log_debug("%s: %u = %s (type %d)", __func__, i, s,
212 			    value->type);
213 
214 			if (parse->cb != NULL) {
215 				type = parse->cb(args, args->count, cause);
216 				if (type == ARGS_PARSE_INVALID) {
217 					args_free(args);
218 					return (NULL);
219 				}
220 			} else
221 				type = ARGS_PARSE_STRING;
222 
223 			args->values = xrecallocarray(args->values,
224 			    args->count, args->count + 1, sizeof *args->values);
225 			new = &args->values[args->count++];
226 
227 			switch (type) {
228 			case ARGS_PARSE_INVALID:
229 				fatalx("unexpected argument type");
230 			case ARGS_PARSE_STRING:
231 				if (value->type != ARGS_STRING) {
232 					xasprintf(cause,
233 					    "argument %u must be \"string\"",
234 					    args->count);
235 					args_free(args);
236 					return (NULL);
237 				}
238 				args_copy_value(new, value);
239 				break;
240 			case ARGS_PARSE_COMMANDS_OR_STRING:
241 				args_copy_value(new, value);
242 				break;
243 			case ARGS_PARSE_COMMANDS:
244 				if (value->type != ARGS_COMMANDS) {
245 					xasprintf(cause,
246 					    "argument %u must be { commands }",
247 					    args->count);
248 					args_free(args);
249 					return (NULL);
250 				}
251 				args_copy_value(new, value);
252 				break;
253 			}
254 		}
255 	}
256 
257 	if (parse->lower != -1 && args->count < (u_int)parse->lower) {
258 		xasprintf(cause,
259 		    "too few arguments (need at least %u)",
260 		    parse->lower);
261 		args_free(args);
262 		return (NULL);
263 	}
264 	if (parse->upper != -1 && args->count > (u_int)parse->upper) {
265 		xasprintf(cause,
266 		    "too many arguments (need at most %u)",
267 		    parse->upper);
268 		args_free(args);
269 		return (NULL);
270 	}
271 	return (args);
272 }
273 
274 /* Copy and expand a value. */
275 static void
276 args_copy_copy_value(struct args_value *to, struct args_value *from, int argc,
277     char **argv)
278 {
279 	char	*s, *expanded;
280 	int	 i;
281 
282 	to->type = from->type;
283 	switch (from->type) {
284 	case ARGS_NONE:
285 		break;
286 	case ARGS_STRING:
287 		expanded = xstrdup(from->string);
288 		for (i = 0; i < argc; i++) {
289 			s = cmd_template_replace(expanded, argv[i], i + 1);
290 			free(expanded);
291 			expanded = s;
292 		}
293 		to->string = expanded;
294 		break;
295 	case ARGS_COMMANDS:
296 		to->cmdlist = cmd_list_copy(from->cmdlist, argc, argv);
297 		break;
298 	}
299 }
300 
301 /* Copy an arguments set. */
302 struct args *
303 args_copy(struct args *args, int argc, char **argv)
304 {
305 	struct args		*new_args;
306 	struct args_entry	*entry;
307 	struct args_value	*value, *new_value;
308 	u_int			 i;
309 
310 	cmd_log_argv(argc, argv, "%s", __func__);
311 
312 	new_args = args_create();
313 	RB_FOREACH(entry, args_tree, &args->tree) {
314 		if (TAILQ_EMPTY(&entry->values)) {
315 			for (i = 0; i < entry->count; i++)
316 				args_set(new_args, entry->flag, NULL);
317 			continue;
318 		}
319 		TAILQ_FOREACH(value, &entry->values, entry) {
320 			new_value = xcalloc(1, sizeof *new_value);
321 			args_copy_copy_value(new_value, value, argc, argv);
322 			args_set(new_args, entry->flag, new_value);
323 		}
324 	}
325 	if (args->count == 0)
326 		return (new_args);
327 	new_args->count = args->count;
328 	new_args->values = xcalloc(args->count, sizeof *new_args->values);
329 	for (i = 0; i < args->count; i++) {
330 		new_value = &new_args->values[i];
331 		args_copy_copy_value(new_value, &args->values[i], argc, argv);
332 	}
333 	return (new_args);
334 }
335 
336 /* Free a value. */
337 void
338 args_free_value(struct args_value *value)
339 {
340 	switch (value->type) {
341 	case ARGS_NONE:
342 		break;
343 	case ARGS_STRING:
344 		free(value->string);
345 		break;
346 	case ARGS_COMMANDS:
347 		cmd_list_free(value->cmdlist);
348 		break;
349 	}
350 	free(value->cached);
351 }
352 
353 /* Free values. */
354 void
355 args_free_values(struct args_value *values, u_int count)
356 {
357 	u_int	i;
358 
359 	for (i = 0; i < count; i++)
360 		args_free_value(&values[i]);
361 }
362 
363 /* Free an arguments set. */
364 void
365 args_free(struct args *args)
366 {
367 	struct args_entry	*entry;
368 	struct args_entry	*entry1;
369 	struct args_value	*value;
370 	struct args_value	*value1;
371 
372 	args_free_values(args->values, args->count);
373 	free(args->values);
374 
375 	RB_FOREACH_SAFE(entry, args_tree, &args->tree, entry1) {
376 		RB_REMOVE(args_tree, &args->tree, entry);
377 		TAILQ_FOREACH_SAFE(value, &entry->values, entry, value1) {
378 			TAILQ_REMOVE(&entry->values, value, entry);
379 			args_free_value(value);
380 			free(value);
381 		}
382 		free(entry);
383 	}
384 
385 	free(args);
386 }
387 
388 /* Convert arguments to vector. */
389 void
390 args_to_vector(struct args *args, int *argc, char ***argv)
391 {
392 	char	*s;
393 	u_int	 i;
394 
395 	*argc = 0;
396 	*argv = NULL;
397 
398 	for (i = 0; i < args->count; i++) {
399 		switch (args->values[i].type) {
400 		case ARGS_NONE:
401 			break;
402 		case ARGS_STRING:
403 			cmd_append_argv(argc, argv, args->values[i].string);
404 			break;
405 		case ARGS_COMMANDS:
406 			s = cmd_list_print(args->values[i].cmdlist, 0);
407 			cmd_append_argv(argc, argv, s);
408 			free(s);
409 			break;
410 		}
411 	}
412 }
413 
414 /* Convert arguments from vector. */
415 struct args_value *
416 args_from_vector(int argc, char **argv)
417 {
418 	struct args_value	*values;
419 	int			 i;
420 
421 	values = xcalloc(argc, sizeof *values);
422 	for (i = 0; i < argc; i++) {
423 		values[i].type = ARGS_STRING;
424 		values[i].string = xstrdup(argv[i]);
425 	}
426 	return (values);
427 }
428 
429 /* Add to string. */
430 static void printflike(3, 4)
431 args_print_add(char **buf, size_t *len, const char *fmt, ...)
432 {
433 	va_list	 ap;
434 	char	*s;
435 	size_t	 slen;
436 
437 	va_start(ap, fmt);
438 	slen = xvasprintf(&s, fmt, ap);
439 	va_end(ap);
440 
441 	*len += slen;
442 	*buf = xrealloc(*buf, *len);
443 
444 	strlcat(*buf, s, *len);
445 	free(s);
446 }
447 
448 /* Add value to string. */
449 static void
450 args_print_add_value(char **buf, size_t *len, struct args_value *value)
451 {
452 	char	*expanded = NULL;
453 
454 	if (**buf != '\0')
455 		args_print_add(buf, len, " ");
456 
457 	switch (value->type) {
458 	case ARGS_NONE:
459 		break;
460 	case ARGS_COMMANDS:
461 		expanded = cmd_list_print(value->cmdlist, 0);
462 		args_print_add(buf, len, "{ %s }", expanded);
463 		break;
464 	case ARGS_STRING:
465 		expanded = args_escape(value->string);
466 		args_print_add(buf, len, "%s", expanded);
467 		break;
468 	}
469 	free(expanded);
470 }
471 
472 /* Print a set of arguments. */
473 char *
474 args_print(struct args *args)
475 {
476 	size_t			 len;
477 	char			*buf;
478 	u_int			 i, j;
479 	struct args_entry	*entry;
480 	struct args_value	*value;
481 
482 	len = 1;
483 	buf = xcalloc(1, len);
484 
485 	/* Process the flags first. */
486 	RB_FOREACH(entry, args_tree, &args->tree) {
487 		if (!TAILQ_EMPTY(&entry->values))
488 			continue;
489 
490 		if (*buf == '\0')
491 			args_print_add(&buf, &len, "-");
492 		for (j = 0; j < entry->count; j++)
493 			args_print_add(&buf, &len, "%c", entry->flag);
494 	}
495 
496 	/* Then the flags with arguments. */
497 	RB_FOREACH(entry, args_tree, &args->tree) {
498 		TAILQ_FOREACH(value, &entry->values, entry) {
499 			if (*buf != '\0')
500 				args_print_add(&buf, &len, " -%c", entry->flag);
501 			else
502 				args_print_add(&buf, &len, "-%c", entry->flag);
503 			args_print_add_value(&buf, &len, value);
504 		}
505 	}
506 
507 	/* And finally the argument vector. */
508 	for (i = 0; i < args->count; i++)
509 		args_print_add_value(&buf, &len, &args->values[i]);
510 
511 	return (buf);
512 }
513 
514 /* Escape an argument. */
515 char *
516 args_escape(const char *s)
517 {
518 	static const char	 dquoted[] = " #';${}%";
519 	static const char	 squoted[] = " \"";
520 	char			*escaped, *result;
521 	int			 flags, quotes = 0;
522 
523 	if (*s == '\0') {
524 		xasprintf(&result, "''");
525 		return (result);
526 	}
527 	if (s[strcspn(s, dquoted)] != '\0')
528 		quotes = '"';
529 	else if (s[strcspn(s, squoted)] != '\0')
530 		quotes = '\'';
531 
532 	if (s[0] != ' ' &&
533 	    s[1] == '\0' &&
534 	    (quotes != 0 || s[0] == '~')) {
535 		xasprintf(&escaped, "\\%c", s[0]);
536 		return (escaped);
537 	}
538 
539 	flags = VIS_OCTAL|VIS_CSTYLE|VIS_TAB|VIS_NL;
540 	if (quotes == '"')
541 		flags |= VIS_DQ;
542 	utf8_stravis(&escaped, s, flags);
543 
544 	if (quotes == '\'')
545 		xasprintf(&result, "'%s'", escaped);
546 	else if (quotes == '"') {
547 		if (*escaped == '~')
548 			xasprintf(&result, "\"\\%s\"", escaped);
549 		else
550 			xasprintf(&result, "\"%s\"", escaped);
551 	} else {
552 		if (*escaped == '~')
553 			xasprintf(&result, "\\%s", escaped);
554 		else
555 			result = xstrdup(escaped);
556 	}
557 	free(escaped);
558 	return (result);
559 }
560 
561 /* Return if an argument is present. */
562 int
563 args_has(struct args *args, u_char flag)
564 {
565 	struct args_entry	*entry;
566 
567 	entry = args_find(args, flag);
568 	if (entry == NULL)
569 		return (0);
570 	return (entry->count);
571 }
572 
573 /* Set argument value in the arguments tree. */
574 void
575 args_set(struct args *args, u_char flag, struct args_value *value)
576 {
577 	struct args_entry	*entry;
578 
579 	entry = args_find(args, flag);
580 	if (entry == NULL) {
581 		entry = xcalloc(1, sizeof *entry);
582 		entry->flag = flag;
583 		entry->count = 1;
584 		TAILQ_INIT(&entry->values);
585 		RB_INSERT(args_tree, &args->tree, entry);
586 	} else
587 		entry->count++;
588 	if (value != NULL && value->type != ARGS_NONE)
589 		TAILQ_INSERT_TAIL(&entry->values, value, entry);
590 }
591 
592 /* Get argument value. Will be NULL if it isn't present. */
593 const char *
594 args_get(struct args *args, u_char flag)
595 {
596 	struct args_entry	*entry;
597 
598 	if ((entry = args_find(args, flag)) == NULL)
599 		return (NULL);
600 	if (TAILQ_EMPTY(&entry->values))
601 		return (NULL);
602 	return (TAILQ_LAST(&entry->values, args_values)->string);
603 }
604 
605 /* Get first argument. */
606 u_char
607 args_first(struct args *args, struct args_entry **entry)
608 {
609 	*entry = RB_MIN(args_tree, &args->tree);
610 	if (*entry == NULL)
611 		return (0);
612 	return ((*entry)->flag);
613 }
614 
615 /* Get next argument. */
616 u_char
617 args_next(struct args_entry **entry)
618 {
619 	*entry = RB_NEXT(args_tree, &args->tree, *entry);
620 	if (*entry == NULL)
621 		return (0);
622 	return ((*entry)->flag);
623 }
624 
625 /* Get argument count. */
626 u_int
627 args_count(struct args *args)
628 {
629 	return (args->count);
630 }
631 
632 /* Get argument values. */
633 struct args_value *
634 args_values(struct args *args)
635 {
636 	return (args->values);
637 }
638 
639 /* Get argument value. */
640 struct args_value *
641 args_value(struct args *args, u_int idx)
642 {
643 	if (idx >= args->count)
644 		return (NULL);
645 	return (&args->values[idx]);
646 }
647 
648 /* Return argument as string. */
649 const char *
650 args_string(struct args *args, u_int idx)
651 {
652 	if (idx >= args->count)
653 		return (NULL);
654 	return (args_value_as_string(&args->values[idx]));
655 }
656 
657 /* Make a command now. */
658 struct cmd_list *
659 args_make_commands_now(struct cmd *self, struct cmdq_item *item, u_int idx,
660     int expand)
661 {
662 	struct args_command_state	*state;
663 	char				*error;
664 	struct cmd_list			*cmdlist;
665 
666 	state = args_make_commands_prepare(self, item, idx, NULL, 0, expand);
667 	cmdlist = args_make_commands(state, 0, NULL, &error);
668 	if (cmdlist == NULL) {
669 		cmdq_error(item, "%s", error);
670 		free(error);
671 	}
672 	else
673 		cmdlist->references++;
674 	args_make_commands_free(state);
675 	return (cmdlist);
676 }
677 
678 /* Save bits to make a command later. */
679 struct args_command_state *
680 args_make_commands_prepare(struct cmd *self, struct cmdq_item *item, u_int idx,
681     const char *default_command, int wait, int expand)
682 {
683 	struct args			*args = cmd_get_args(self);
684 	struct cmd_find_state		*target = cmdq_get_target(item);
685 	struct client			*tc = cmdq_get_target_client(item);
686 	struct args_value		*value;
687 	struct args_command_state	*state;
688 	const char			*cmd;
689 
690 	state = xcalloc(1, sizeof *state);
691 
692 	if (idx < args->count) {
693 		value = &args->values[idx];
694 		if (value->type == ARGS_COMMANDS) {
695 			state->cmdlist = value->cmdlist;
696 			state->cmdlist->references++;
697 			return (state);
698 		}
699 		cmd = value->string;
700 	} else {
701 		if (default_command == NULL)
702 			fatalx("argument out of range");
703 		cmd = default_command;
704 	}
705 
706 
707 	if (expand)
708 		state->cmd = format_single_from_target(item, cmd);
709 	else
710 		state->cmd = xstrdup(cmd);
711 	log_debug("%s: %s", __func__, state->cmd);
712 
713 	if (wait)
714 		state->pi.item = item;
715 	cmd_get_source(self, &state->pi.file, &state->pi.line);
716 	state->pi.c = tc;
717 	if (state->pi.c != NULL)
718 		state->pi.c->references++;
719 	cmd_find_copy_state(&state->pi.fs, target);
720 
721 	return (state);
722 }
723 
724 /* Return argument as command. */
725 struct cmd_list *
726 args_make_commands(struct args_command_state *state, int argc, char **argv,
727     char **error)
728 {
729 	struct cmd_parse_result	*pr;
730 	char			*cmd, *new_cmd;
731 	int			 i;
732 
733 	if (state->cmdlist != NULL) {
734 		if (argc == 0)
735 			return (state->cmdlist);
736 		return (cmd_list_copy(state->cmdlist, argc, argv));
737 	}
738 
739 	cmd = xstrdup(state->cmd);
740 	for (i = 0; i < argc; i++) {
741 		new_cmd = cmd_template_replace(cmd, argv[i], i + 1);
742 		log_debug("%s: %%%u %s: %s", __func__, i + 1, argv[i], new_cmd);
743 		free(cmd);
744 		cmd = new_cmd;
745 	}
746 	log_debug("%s: %s", __func__, cmd);
747 
748 	pr = cmd_parse_from_string(cmd, &state->pi);
749 	free(cmd);
750 	switch (pr->status) {
751 	case CMD_PARSE_ERROR:
752 		*error = pr->error;
753 		return (NULL);
754 	case CMD_PARSE_SUCCESS:
755 		return (pr->cmdlist);
756 	}
757 	fatalx("invalid parse return state");
758 }
759 
760 /* Free commands state. */
761 void
762 args_make_commands_free(struct args_command_state *state)
763 {
764 	if (state->cmdlist != NULL)
765 		cmd_list_free(state->cmdlist);
766 	if (state->pi.c != NULL)
767 		server_client_unref(state->pi.c);
768 	free(state->cmd);
769 	free(state);
770 }
771 
772 /* Get prepared command. */
773 char *
774 args_make_commands_get_command(struct args_command_state *state)
775 {
776 	struct cmd	*first;
777 	int		 n;
778 	char		*s;
779 
780 	if (state->cmdlist != NULL) {
781 		first = cmd_list_first(state->cmdlist);
782 		if (first == NULL)
783 			return (xstrdup(""));
784 		return (xstrdup(cmd_get_entry(first)->name));
785 	}
786 	n = strcspn(state->cmd, " ,");
787 	xasprintf(&s, "%.*s", n, state->cmd);
788 	return (s);
789 }
790 
791 /* Get first value in argument. */
792 struct args_value *
793 args_first_value(struct args *args, u_char flag)
794 {
795 	struct args_entry	*entry;
796 
797 	if ((entry = args_find(args, flag)) == NULL)
798 		return (NULL);
799 	return (TAILQ_FIRST(&entry->values));
800 }
801 
802 /* Get next value in argument. */
803 struct args_value *
804 args_next_value(struct args_value *value)
805 {
806 	return (TAILQ_NEXT(value, entry));
807 }
808 
809 /* Convert an argument value to a number. */
810 long long
811 args_strtonum(struct args *args, u_char flag, long long minval,
812     long long maxval, char **cause)
813 {
814 	const char		*errstr;
815 	long long		 ll;
816 	struct args_entry	*entry;
817 	struct args_value	*value;
818 
819 	if ((entry = args_find(args, flag)) == NULL) {
820 		*cause = xstrdup("missing");
821 		return (0);
822 	}
823 	value = TAILQ_LAST(&entry->values, args_values);
824 
825 	ll = strtonum(value->string, minval, maxval, &errstr);
826 	if (errstr != NULL) {
827 		*cause = xstrdup(errstr);
828 		return (0);
829 	}
830 
831 	*cause = NULL;
832 	return (ll);
833 }
834 
835 /* Convert an argument to a number which may be a percentage. */
836 long long
837 args_percentage(struct args *args, u_char flag, long long minval,
838     long long maxval, long long curval, char **cause)
839 {
840 	const char		*value;
841 	struct args_entry	*entry;
842 
843 	if ((entry = args_find(args, flag)) == NULL) {
844 		*cause = xstrdup("missing");
845 		return (0);
846 	}
847 	value = TAILQ_LAST(&entry->values, args_values)->string;
848 	return (args_string_percentage(value, minval, maxval, curval, cause));
849 }
850 
851 /* Convert a string to a number which may be a percentage. */
852 long long
853 args_string_percentage(const char *value, long long minval, long long maxval,
854     long long curval, char **cause)
855 {
856 	const char	*errstr;
857 	long long	 ll;
858 	size_t		 valuelen = strlen(value);
859 	char		*copy;
860 
861 	if (value[valuelen - 1] == '%') {
862 		copy = xstrdup(value);
863 		copy[valuelen - 1] = '\0';
864 
865 		ll = strtonum(copy, 0, 100, &errstr);
866 		free(copy);
867 		if (errstr != NULL) {
868 			*cause = xstrdup(errstr);
869 			return (0);
870 		}
871 		ll = (curval * ll) / 100;
872 		if (ll < minval) {
873 			*cause = xstrdup("too small");
874 			return (0);
875 		}
876 		if (ll > maxval) {
877 			*cause = xstrdup("too large");
878 			return (0);
879 		}
880 	} else {
881 		ll = strtonum(value, minval, maxval, &errstr);
882 		if (errstr != NULL) {
883 			*cause = xstrdup(errstr);
884 			return (0);
885 		}
886 	}
887 
888 	*cause = NULL;
889 	return (ll);
890 }
891