1 /*
2 * Copyright (C) 1984-2025 Mark Nudelman
3 *
4 * You may distribute under the terms of either the GNU General Public
5 * License or the Less License, as specified in the README file.
6 *
7 * For more information, see the README file.
8 */
9
10
11 /*
12 * Process command line options.
13 *
14 * Each option is a single letter which controls a program variable.
15 * The options have defaults which may be changed via
16 * the command line option, toggled via the "-" command,
17 * or queried via the "_" command.
18 */
19
20 #include "less.h"
21 #include "option.h"
22
23 static struct loption *pendopt;
24 public lbool plusoption = FALSE;
25
26 static constant char *optstring(constant char *s, char **p_str, constant char *printopt, constant char *validchars);
27 static int flip_triple(int val, lbool lc);
28
29 extern int less_is_more;
30 extern int quit_at_eof;
31 extern char *every_first_cmd;
32 extern int opt_use_backslash;
33 extern int ctldisp;
34
35 /*
36 * Return a printable description of an option.
37 */
opt_desc(struct loption * o)38 static constant char * opt_desc(struct loption *o)
39 {
40 static char buf[OPTNAME_MAX + 10];
41 if (o->oletter == OLETTER_NONE)
42 SNPRINTF1(buf, sizeof(buf), "--%s", o->onames->oname);
43 else
44 SNPRINTF2(buf, sizeof(buf), "-%c (--%s)", o->oletter, o->onames->oname);
45 return (buf);
46 }
47
48 /*
49 * Return a string suitable for printing as the "name" of an option.
50 * For example, if the option letter is 'x', just return "-x".
51 */
propt(char c)52 public constant char * propt(char c)
53 {
54 static char buf[MAX_PRCHAR_LEN+2];
55
56 sprintf(buf, "-%s", prchar((LWCHAR) c));
57 return (buf);
58 }
59
60 /*
61 * Scan an argument (either from the command line or from the
62 * LESS environment variable) and process it.
63 */
scan_option(constant char * s,lbool is_env)64 public void scan_option(constant char *s, lbool is_env)
65 {
66 struct loption *o;
67 char optc;
68 constant char *optname;
69 constant char *printopt;
70 char *str;
71 lbool set_default;
72 lbool lc;
73 lbool ambig;
74 PARG parg;
75
76 if (s == NULL)
77 return;
78
79 /*
80 * If we have a pending option which requires an argument,
81 * handle it now.
82 * This happens if the previous option was, for example, "-P"
83 * without a following string. In that case, the current
84 * option is simply the argument for the previous option.
85 */
86 if (pendopt != NULL)
87 {
88 if (!(pendopt->otype & O_UNSUPPORTED))
89 {
90 switch (pendopt->otype & OTYPE)
91 {
92 case O_STRING:
93 (*pendopt->ofunc)(INIT, s);
94 break;
95 case O_NUMBER:
96 printopt = opt_desc(pendopt);
97 *(pendopt->ovar) = getnumc(&s, printopt, NULL);
98 break;
99 }
100 }
101 pendopt = NULL;
102 return;
103 }
104
105 set_default = FALSE;
106 optname = NULL;
107
108 while (*s != '\0')
109 {
110 /*
111 * Check some special cases first.
112 */
113 switch (optc = *s++)
114 {
115 case ' ':
116 case '\t':
117 case END_OPTION_STRING:
118 continue;
119 case '-':
120 /*
121 * "--" indicates an option name instead of a letter.
122 */
123 if (*s == '-')
124 optname = ++s;
125 /*
126 * "-+" or "--+" means set these options back to their defaults.
127 * (They may have been set otherwise by previous options.)
128 */
129 set_default = (*s == '+');
130 if (set_default)
131 s++;
132 if (optname != NULL)
133 {
134 optname = s;
135 break;
136 }
137 continue;
138 case '+':
139 /*
140 * An option prefixed by a "+" is ungotten, so
141 * that it is interpreted as less commands
142 * processed at the start of the first input file.
143 * "++" means process the commands at the start of
144 * EVERY input file.
145 */
146 plusoption = TRUE;
147 s = optstring(s, &str, propt('+'), NULL);
148 if (s == NULL)
149 return;
150 if (*str == '+')
151 {
152 if (every_first_cmd != NULL)
153 free(every_first_cmd);
154 every_first_cmd = save(str+1);
155 } else
156 {
157 ungetsc(str);
158 ungetcc_end_command();
159 }
160 free(str);
161 continue;
162 case '0': case '1': case '2': case '3': case '4':
163 case '5': case '6': case '7': case '8': case '9':
164 /*
165 * Special "more" compatibility form "-<number>"
166 * instead of -z<number> to set the scrolling
167 * window size.
168 */
169 s--;
170 optc = 'z';
171 break;
172 case 'n':
173 if (less_is_more)
174 optc = 'z';
175 break;
176 }
177
178 /*
179 * Not a special case.
180 * Look up the option letter in the option table.
181 */
182 ambig = FALSE;
183 if (optname == NULL)
184 {
185 printopt = propt(optc);
186 lc = ASCII_IS_LOWER(optc);
187 o = findopt(optc);
188 } else
189 {
190 printopt = optname;
191 lc = ASCII_IS_LOWER(optname[0]);
192 o = findopt_name(&optname, NULL, &ambig);
193 s = optname;
194 optname = NULL;
195 if (*s == '\0' || *s == ' ')
196 {
197 /*
198 * The option name matches exactly.
199 */
200 ;
201 } else if (*s == '=')
202 {
203 /*
204 * The option name is followed by "=value".
205 */
206 if (o != NULL &&
207 (o->otype & OTYPE) != O_STRING &&
208 (o->otype & OTYPE) != O_NUMBER)
209 {
210 parg.p_string = printopt;
211 error("The %s option should not be followed by =",
212 &parg);
213 return;
214 }
215 s++;
216 } else
217 {
218 /*
219 * The specified name is longer than the
220 * real option name.
221 */
222 o = NULL;
223 }
224 }
225 if (o == NULL)
226 {
227 parg.p_string = printopt;
228 if (ambig)
229 error("%s is an ambiguous abbreviation (\"less --help\" for help)",
230 &parg);
231 else
232 error("There is no %s option (\"less --help\" for help)",
233 &parg);
234 return;
235 }
236
237 str = NULL;
238 switch (o->otype & OTYPE)
239 {
240 case O_BOOL:
241 if (o->otype & O_UNSUPPORTED)
242 break;
243 if (o->ovar != NULL)
244 {
245 if (set_default)
246 *(o->ovar) = o->odefault;
247 else
248 *(o->ovar) = ! o->odefault;
249 }
250 break;
251 case O_TRIPLE:
252 if (o->otype & O_UNSUPPORTED)
253 break;
254 if (o->ovar != NULL)
255 {
256 if (set_default)
257 *(o->ovar) = o->odefault;
258 else if (is_env && o->ovar == &ctldisp)
259 /* If -r appears in an env var, treat it as -R. */
260 *(o->ovar) = OPT_ONPLUS;
261 else
262 *(o->ovar) = flip_triple(o->odefault, lc);
263 }
264 break;
265 case O_STRING:
266 if (*s == '\0')
267 {
268 /*
269 * Set pendopt and return.
270 * We will get the string next time
271 * scan_option is called.
272 */
273 pendopt = o;
274 return;
275 }
276 /*
277 * Don't do anything here.
278 * All processing of STRING options is done by
279 * the handling function.
280 */
281 while (*s == ' ')
282 s++;
283 s = optstring(s, &str, printopt, o->odesc[1]);
284 if (s == NULL)
285 return;
286 break;
287 case O_NUMBER:
288 if (*s == '\0')
289 {
290 pendopt = o;
291 return;
292 }
293 if (o->otype & O_UNSUPPORTED)
294 break;
295 *(o->ovar) = getnumc(&s, printopt, NULL);
296 break;
297 }
298 /*
299 * If the option has a handling function, call it.
300 */
301 if (o->ofunc != NULL && !(o->otype & O_UNSUPPORTED))
302 (*o->ofunc)(INIT, str);
303 if (str != NULL)
304 free(str);
305 }
306 }
307
308 /*
309 * Toggle command line flags from within the program.
310 * Used by the "-" and "_" commands.
311 * how_toggle may be:
312 * OPT_NO_TOGGLE just report the current setting, without changing it.
313 * OPT_TOGGLE invert the current setting
314 * OPT_UNSET set to the default value
315 * OPT_SET set to the inverse of the default value
316 */
toggle_option(struct loption * o,lbool lower,constant char * s,int how_toggle)317 public void toggle_option(struct loption *o, lbool lower, constant char *s, int how_toggle)
318 {
319 int num;
320 int no_prompt;
321 lbool err;
322 PARG parg;
323
324 no_prompt = (how_toggle & OPT_NO_PROMPT);
325 how_toggle &= ~OPT_NO_PROMPT;
326
327 if (o == NULL)
328 {
329 error("No such option", NULL_PARG);
330 return;
331 }
332
333 if (how_toggle == OPT_TOGGLE && (o->otype & O_NO_TOGGLE))
334 {
335 parg.p_string = opt_desc(o);
336 error("Cannot change the %s option", &parg);
337 return;
338 }
339
340 if (how_toggle == OPT_NO_TOGGLE && (o->otype & O_NO_QUERY))
341 {
342 parg.p_string = opt_desc(o);
343 error("Cannot query the %s option", &parg);
344 return;
345 }
346
347 /*
348 * Check for something which appears to be a do_toggle
349 * (because the "-" command was used), but really is not.
350 * This could be a string option with no string, or
351 * a number option with no number.
352 */
353 switch (o->otype & OTYPE)
354 {
355 case O_STRING:
356 case O_NUMBER:
357 if (how_toggle == OPT_TOGGLE && *s == '\0')
358 how_toggle = OPT_NO_TOGGLE;
359 break;
360 }
361
362 #if HILITE_SEARCH
363 if (how_toggle != OPT_NO_TOGGLE && (o->otype & O_HL_REPAINT))
364 repaint_hilite(FALSE);
365 #endif
366
367 /*
368 * Now actually toggle (change) the variable.
369 */
370 if (how_toggle != OPT_NO_TOGGLE)
371 {
372 switch (o->otype & OTYPE)
373 {
374 case O_BOOL:
375 /*
376 * Boolean.
377 */
378 if (o->ovar != NULL)
379 {
380 switch (how_toggle)
381 {
382 case OPT_TOGGLE:
383 *(o->ovar) = ! *(o->ovar);
384 break;
385 case OPT_UNSET:
386 *(o->ovar) = o->odefault;
387 break;
388 case OPT_SET:
389 *(o->ovar) = ! o->odefault;
390 break;
391 }
392 }
393 break;
394 case O_TRIPLE:
395 /*
396 * Triple:
397 * If user gave the lower case letter, then switch
398 * to 1 unless already 1, in which case make it 0.
399 * If user gave the upper case letter, then switch
400 * to 2 unless already 2, in which case make it 0.
401 */
402 if (o->ovar != NULL)
403 {
404 switch (how_toggle)
405 {
406 case OPT_TOGGLE:
407 *(o->ovar) = flip_triple(*(o->ovar), lower);
408 break;
409 case OPT_UNSET:
410 *(o->ovar) = o->odefault;
411 break;
412 case OPT_SET:
413 *(o->ovar) = flip_triple(o->odefault, lower);
414 break;
415 }
416 }
417 break;
418 case O_STRING:
419 /*
420 * String: don't do anything here.
421 * The handling function will do everything.
422 */
423 switch (how_toggle)
424 {
425 case OPT_SET:
426 case OPT_UNSET:
427 error("Cannot use \"-+\" or \"-!\" for a string option",
428 NULL_PARG);
429 return;
430 }
431 break;
432 case O_NUMBER:
433 /*
434 * Number: set the variable to the given number.
435 */
436 switch (how_toggle)
437 {
438 case OPT_TOGGLE:
439 num = getnumc(&s, NULL, &err);
440 if (!err)
441 *(o->ovar) = num;
442 break;
443 case OPT_UNSET:
444 *(o->ovar) = o->odefault;
445 break;
446 case OPT_SET:
447 error("Can't use \"-!\" for a numeric option",
448 NULL_PARG);
449 return;
450 }
451 break;
452 }
453 }
454
455 /*
456 * Call the handling function for any special action
457 * specific to this option.
458 */
459 if (o->ofunc != NULL)
460 (*o->ofunc)((how_toggle==OPT_NO_TOGGLE) ? QUERY : TOGGLE, s);
461
462 #if HILITE_SEARCH
463 if (how_toggle != OPT_NO_TOGGLE && (o->otype & O_HL_REPAINT))
464 chg_hilite();
465 #endif
466
467 if (!no_prompt)
468 {
469 /*
470 * Print a message describing the new setting.
471 */
472 switch (o->otype & OTYPE)
473 {
474 case O_BOOL:
475 case O_TRIPLE:
476 /*
477 * Print the odesc message.
478 */
479 if (o->ovar != NULL)
480 error(o->odesc[*(o->ovar)], NULL_PARG);
481 break;
482 case O_NUMBER:
483 /*
484 * The message is in odesc[1] and has a %d for
485 * the value of the variable.
486 */
487 parg.p_int = *(o->ovar);
488 error(o->odesc[1], &parg);
489 break;
490 case O_STRING:
491 /*
492 * Message was already printed by the handling function.
493 */
494 break;
495 }
496 }
497
498 if (how_toggle != OPT_NO_TOGGLE && (o->otype & O_REPAINT))
499 screen_trashed();
500 }
501
502 /*
503 * "Toggle" a triple-valued option.
504 */
flip_triple(int val,lbool lc)505 static int flip_triple(int val, lbool lc)
506 {
507 if (lc)
508 return ((val == OPT_ON) ? OPT_OFF : OPT_ON);
509 else
510 return ((val == OPT_ONPLUS) ? OPT_OFF : OPT_ONPLUS);
511 }
512
513 /*
514 * Determine if an option takes a parameter.
515 */
opt_has_param(struct loption * o)516 public int opt_has_param(struct loption *o)
517 {
518 if (o == NULL)
519 return (0);
520 if (o->otype & (O_BOOL|O_TRIPLE|O_NOVAR|O_NO_TOGGLE))
521 return (0);
522 return (1);
523 }
524
525 /*
526 * Return the prompt to be used for a given option letter.
527 * Only string and number valued options have prompts.
528 */
opt_prompt(struct loption * o)529 public constant char * opt_prompt(struct loption *o)
530 {
531 if (o == NULL || (o->otype & (O_STRING|O_NUMBER)) == 0)
532 return ("?");
533 return (o->odesc[0]);
534 }
535
536 /*
537 * If the specified option can be toggled, return NULL.
538 * Otherwise return an appropriate error message.
539 */
opt_toggle_disallowed(int c)540 public constant char * opt_toggle_disallowed(int c)
541 {
542 switch (c)
543 {
544 case 'o':
545 if (ch_getflags() & CH_CANSEEK)
546 return "Input is not a pipe";
547 break;
548 }
549 return NULL;
550 }
551
552 /*
553 * Return whether or not there is a string option pending;
554 * that is, if the previous option was a string-valued option letter
555 * (like -P) without a following string.
556 * In that case, the current option is taken to be the string for
557 * the previous option.
558 */
isoptpending(void)559 public lbool isoptpending(void)
560 {
561 return (pendopt != NULL);
562 }
563
564 /*
565 * Print error message about missing string.
566 */
nostring(constant char * printopt)567 static void nostring(constant char *printopt)
568 {
569 PARG parg;
570 parg.p_string = printopt;
571 error("Value is required after %s", &parg);
572 }
573
574 /*
575 * Print error message if a STRING type option is not followed by a string.
576 */
nopendopt(void)577 public void nopendopt(void)
578 {
579 nostring(opt_desc(pendopt));
580 }
581
582 /*
583 * Scan to end of string or to an END_OPTION_STRING character.
584 * In the latter case, replace the char with a null char.
585 * Return a pointer to the remainder of the string, if any.
586 * validchars is of the form "[-][.]d[,]".
587 * "-" means an optional leading "-" is allowed
588 * "." means an optional leading "." is allowed (after any "-")
589 * "d" indicates a string of one or more digits (0-9)
590 * "," indicates a comma-separated list of digit strings is allowed
591 * "s" means a space char terminates the argument
592 */
optstring(constant char * s,char ** p_str,constant char * printopt,constant char * validchars)593 static constant char * optstring(constant char *s, char **p_str, constant char *printopt, constant char *validchars)
594 {
595 constant char *p;
596 char *out;
597
598 if (*s == '\0')
599 {
600 nostring(printopt);
601 return (NULL);
602 }
603 /* Alloc could be more than needed, but not worth trimming. */
604 *p_str = (char *) ecalloc(strlen(s)+1, sizeof(char));
605 out = *p_str;
606
607 for (p = s; *p != '\0'; p++)
608 {
609 if (opt_use_backslash && *p == '\\' && p[1] != '\0')
610 {
611 /* Take next char literally. */
612 ++p;
613 } else
614 {
615 if (validchars != NULL)
616 {
617 if (validchars[0] == 's')
618 {
619 if (*p == ' ')
620 break;
621 } else if (*p == '-')
622 {
623 if (validchars[0] != '-')
624 break;
625 ++validchars;
626 } else if (*p == '.')
627 {
628 if (validchars[0] == '-')
629 ++validchars;
630 if (validchars[0] != '.')
631 break;
632 ++validchars;
633 } else if (*p == ',')
634 {
635 if (validchars[0] == '\0' || validchars[1] != ',')
636 break;
637 } else if (*p >= '0' && *p <= '9')
638 {
639 while (validchars[0] == '-' || validchars[0] == '.')
640 ++validchars;
641 if (validchars[0] != 'd')
642 break;
643 } else
644 break;
645 }
646 if (*p == END_OPTION_STRING)
647 /* End of option string. */
648 break;
649 }
650 *out++ = *p;
651 }
652 *out = '\0';
653 return (p);
654 }
655
656 /*
657 */
num_error(constant char * printopt,lbool * errp,lbool overflow)658 static int num_error(constant char *printopt, lbool *errp, lbool overflow)
659 {
660 PARG parg;
661
662 if (errp != NULL)
663 {
664 *errp = TRUE;
665 return (-1);
666 }
667 if (printopt != NULL)
668 {
669 parg.p_string = printopt;
670 error((overflow
671 ? "Number too large in '%s'"
672 : "Number is required after %s"),
673 &parg);
674 }
675 return (-1);
676 }
677
678 /*
679 * Translate a string into a number.
680 * Like atoi(), but takes a pointer to a char *, and updates
681 * the char * to point after the translated number.
682 */
getnumc(constant char ** sp,constant char * printopt,lbool * errp)683 public int getnumc(constant char **sp, constant char *printopt, lbool *errp)
684 {
685 constant char *s = *sp;
686 int n;
687 lbool neg;
688
689 s = skipspc(s);
690 neg = FALSE;
691 if (*s == '-')
692 {
693 neg = TRUE;
694 s++;
695 }
696 if (*s < '0' || *s > '9')
697 return (num_error(printopt, errp, FALSE));
698
699 n = lstrtoic(s, sp, 10);
700 if (n < 0)
701 return (num_error(printopt, errp, TRUE));
702 if (errp != NULL)
703 *errp = FALSE;
704 if (neg)
705 n = -n;
706 return (n);
707 }
708
getnum(char ** sp,constant char * printopt,lbool * errp)709 public int getnum(char **sp, constant char *printopt, lbool *errp)
710 {
711 constant char *cs = *sp;
712 int r = getnumc(&cs, printopt, errp);
713 *sp = (char *) cs;
714 return r;
715 }
716
717 /*
718 * Translate a string into a fraction, represented by the part of a
719 * number which would follow a decimal point.
720 * The value of the fraction is returned as parts per NUM_FRAC_DENOM.
721 * That is, if "n" is returned, the fraction intended is n/NUM_FRAC_DENOM.
722 */
getfraction(constant char ** sp,constant char * printopt,lbool * errp)723 public long getfraction(constant char **sp, constant char *printopt, lbool *errp)
724 {
725 constant char *s;
726 long frac = 0;
727 int fraclen = 0;
728
729 s = skipspc(*sp);
730 if (*s < '0' || *s > '9')
731 return (num_error(printopt, errp, FALSE));
732
733 for ( ; *s >= '0' && *s <= '9'; s++)
734 {
735 if (NUM_LOG_FRAC_DENOM <= fraclen)
736 continue;
737 frac = (frac * 10) + (*s - '0');
738 fraclen++;
739 }
740 while (fraclen++ < NUM_LOG_FRAC_DENOM)
741 frac *= 10;
742 *sp = s;
743 if (errp != NULL)
744 *errp = FALSE;
745 return (frac);
746 }
747
748 /*
749 * Set the UNSUPPORTED bit in every option listed
750 * in the LESS_UNSUPPORT environment variable.
751 */
init_unsupport(void)752 public void init_unsupport(void)
753 {
754 constant char *s = lgetenv("LESS_UNSUPPORT");
755 if (isnullenv(s))
756 return;
757 for (;;)
758 {
759 struct loption *opt;
760 s = skipspc(s);
761 if (*s == '\0') break;
762 if (*s == '-' && *++s == '\0') break;
763 if (*s == '-') /* long option name */
764 {
765 ++s;
766 opt = findopt_name(&s, NULL, NULL);
767 } else /* short (single-char) option */
768 {
769 opt = findopt(*s);
770 if (opt != NULL) ++s;
771 }
772 if (opt != NULL)
773 opt->otype |= O_UNSUPPORTED;
774 }
775 }
776
777 /*
778 * Get the value of the -e flag.
779 */
get_quit_at_eof(void)780 public int get_quit_at_eof(void)
781 {
782 if (!less_is_more)
783 return quit_at_eof;
784 /* When less_is_more is set, the -e flag semantics are different. */
785 return quit_at_eof ? OPT_ONPLUS : OPT_ON;
786 }
787