xref: /freebsd/contrib/less/lesskey_parse.c (revision ec965063070e5753c166cf592c9336444b74720a)
1 /*
2  * Copyright (C) 1984-2022  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 #include <stdio.h>
11 #include <string.h>
12 #include <stdlib.h>
13 #include "lesskey.h"
14 #include "cmd.h"
15 #include "xbuf.h"
16 #include "defines.h"
17 
18 #define CONTROL(c)      ((c)&037)
19 #define ESC             CONTROL('[')
20 
21 extern void lesskey_parse_error(char *msg);
22 extern char *homefile(char *filename);
23 extern void *ecalloc(int count, unsigned int size);
24 extern int lstrtoi(char *str, char **end);
25 extern char version[];
26 
27 static int linenum;
28 static int errors;
29 static int less_version = 0;
30 static char *lesskey_file;
31 
32 static struct lesskey_cmdname cmdnames[] =
33 {
34 	{ "back-bracket",         A_B_BRACKET },
35 	{ "back-line",            A_B_LINE },
36 	{ "back-line-force",      A_BF_LINE },
37 	{ "back-screen",          A_B_SCREEN },
38 	{ "back-scroll",          A_B_SCROLL },
39 	{ "back-search",          A_B_SEARCH },
40 	{ "back-window",          A_B_WINDOW },
41 	{ "clear-mark",           A_CLRMARK },
42 	{ "debug",                A_DEBUG },
43 	{ "digit",                A_DIGIT },
44 	{ "display-flag",         A_DISP_OPTION },
45 	{ "display-option",       A_DISP_OPTION },
46 	{ "end",                  A_GOEND },
47 	{ "end-scroll",           A_RRSHIFT },
48 	{ "examine",              A_EXAMINE },
49 	{ "filter",               A_FILTER },
50 	{ "first-cmd",            A_FIRSTCMD },
51 	{ "firstcmd",             A_FIRSTCMD },
52 	{ "flush-repaint",        A_FREPAINT },
53 	{ "forw-bracket",         A_F_BRACKET },
54 	{ "forw-forever",         A_F_FOREVER },
55 	{ "forw-until-hilite",    A_F_UNTIL_HILITE },
56 	{ "forw-line",            A_F_LINE },
57 	{ "forw-line-force",      A_FF_LINE },
58 	{ "forw-screen",          A_F_SCREEN },
59 	{ "forw-screen-force",    A_FF_SCREEN },
60 	{ "forw-scroll",          A_F_SCROLL },
61 	{ "forw-search",          A_F_SEARCH },
62 	{ "forw-window",          A_F_WINDOW },
63 	{ "goto-end",             A_GOEND },
64 	{ "goto-end-buffered",    A_GOEND_BUF },
65 	{ "goto-line",            A_GOLINE },
66 	{ "goto-mark",            A_GOMARK },
67 	{ "help",                 A_HELP },
68 	{ "index-file",           A_INDEX_FILE },
69 	{ "invalid",              A_UINVALID },
70 	{ "left-scroll",          A_LSHIFT },
71 	{ "next-file",            A_NEXT_FILE },
72 	{ "next-tag",             A_NEXT_TAG },
73 	{ "noaction",             A_NOACTION },
74 	{ "no-scroll",            A_LLSHIFT },
75 	{ "percent",              A_PERCENT },
76 	{ "pipe",                 A_PIPE },
77 	{ "prev-file",            A_PREV_FILE },
78 	{ "prev-tag",             A_PREV_TAG },
79 	{ "quit",                 A_QUIT },
80 	{ "remove-file",          A_REMOVE_FILE },
81 	{ "repaint",              A_REPAINT },
82 	{ "repaint-flush",        A_FREPAINT },
83 	{ "repeat-search",        A_AGAIN_SEARCH },
84 	{ "repeat-search-all",    A_T_AGAIN_SEARCH },
85 	{ "reverse-search",       A_REVERSE_SEARCH },
86 	{ "reverse-search-all",   A_T_REVERSE_SEARCH },
87 	{ "right-scroll",         A_RSHIFT },
88 	{ "set-mark",             A_SETMARK },
89 	{ "set-mark-bottom",      A_SETMARKBOT },
90 	{ "shell",                A_SHELL },
91 	{ "status",               A_STAT },
92 	{ "toggle-flag",          A_OPT_TOGGLE },
93 	{ "toggle-option",        A_OPT_TOGGLE },
94 	{ "undo-hilite",          A_UNDO_SEARCH },
95 	{ "clear-search",         A_CLR_SEARCH },
96 	{ "version",              A_VERSION },
97 	{ "visual",               A_VISUAL },
98 	{ NULL,   0 }
99 };
100 
101 static struct lesskey_cmdname editnames[] =
102 {
103 	{ "back-complete",      EC_B_COMPLETE },
104 	{ "backspace",          EC_BACKSPACE },
105 	{ "delete",             EC_DELETE },
106 	{ "down",               EC_DOWN },
107 	{ "end",                EC_END },
108 	{ "expand",             EC_EXPAND },
109 	{ "forw-complete",      EC_F_COMPLETE },
110 	{ "home",               EC_HOME },
111 	{ "insert",             EC_INSERT },
112 	{ "invalid",            EC_UINVALID },
113 	{ "kill-line",          EC_LINEKILL },
114 	{ "abort",              EC_ABORT },
115 	{ "left",               EC_LEFT },
116 	{ "literal",            EC_LITERAL },
117 	{ "right",              EC_RIGHT },
118 	{ "up",                 EC_UP },
119 	{ "word-backspace",     EC_W_BACKSPACE },
120 	{ "word-delete",        EC_W_DELETE },
121 	{ "word-left",          EC_W_LEFT },
122 	{ "word-right",         EC_W_RIGHT },
123 	{ NULL, 0 }
124 };
125 
126 /*
127  * Print a parse error message.
128  */
129 	static void
130 parse_error(fmt, arg1)
131 	char *fmt;
132 	char *arg1;
133 {
134 	char buf[1024];
135 	int n = snprintf(buf, sizeof(buf), "%s: line %d: ", lesskey_file, linenum);
136 	if (n >= 0 && n < sizeof(buf))
137 		snprintf(buf+n, sizeof(buf)-n, fmt, arg1);
138 	++errors;
139 	lesskey_parse_error(buf);
140 }
141 
142 /*
143  * Initialize lesskey_tables.
144  */
145 	static void
146 init_tables(tables)
147 	struct lesskey_tables *tables;
148 {
149 	tables->currtable = &tables->cmdtable;
150 
151 	tables->cmdtable.names = cmdnames;
152 	tables->cmdtable.is_var = 0;
153 	xbuf_init(&tables->cmdtable.buf);
154 
155 	tables->edittable.names = editnames;
156 	tables->edittable.is_var = 0;
157 	xbuf_init(&tables->edittable.buf);
158 
159 	tables->vartable.names = NULL;
160 	tables->vartable.is_var = 1;
161 	xbuf_init(&tables->vartable.buf);
162 }
163 
164 #define CHAR_STRING_LEN 8
165 
166 	static char *
167 char_string(buf, ch, lit)
168 	char *buf;
169 	int ch;
170 	int lit;
171 {
172 	if (lit || (ch >= 0x20 && ch < 0x7f))
173 	{
174 		buf[0] = ch;
175 		buf[1] = '\0';
176 	} else
177 	{
178 		snprintf(buf, CHAR_STRING_LEN, "\\x%02x", ch);
179 	}
180 	return buf;
181 }
182 
183 /*
184  * Increment char pointer by one up to terminating nul byte.
185  */
186 	static char *
187 increment_pointer(p)
188 	char *p;
189 {
190 	if (*p == '\0')
191 		return p;
192 	return p+1;
193 }
194 
195 /*
196  * Parse one character of a string.
197  */
198 	static char *
199 tstr(pp, xlate)
200 	char **pp;
201 	int xlate;
202 {
203 	char *p;
204 	char ch;
205 	int i;
206 	static char buf[CHAR_STRING_LEN];
207 	static char tstr_control_k[] =
208 		{ SK_SPECIAL_KEY, SK_CONTROL_K, 6, 1, 1, 1, '\0' };
209 
210 	p = *pp;
211 	switch (*p)
212 	{
213 	case '\\':
214 		++p;
215 		switch (*p)
216 		{
217 		case '0': case '1': case '2': case '3':
218 		case '4': case '5': case '6': case '7':
219 			/*
220 			 * Parse an octal number.
221 			 */
222 			ch = 0;
223 			i = 0;
224 			do
225 				ch = 8*ch + (*p - '0');
226 			while (*++p >= '0' && *p <= '7' && ++i < 3);
227 			*pp = p;
228 			if (xlate && ch == CONTROL('K'))
229 				return tstr_control_k;
230 			return char_string(buf, ch, 1);
231 		case 'b':
232 			*pp = p+1;
233 			return ("\b");
234 		case 'e':
235 			*pp = p+1;
236 			return char_string(buf, ESC, 1);
237 		case 'n':
238 			*pp = p+1;
239 			return ("\n");
240 		case 'r':
241 			*pp = p+1;
242 			return ("\r");
243 		case 't':
244 			*pp = p+1;
245 			return ("\t");
246 		case 'k':
247 			if (xlate)
248 			{
249 				switch (*++p)
250 				{
251 				case 'b': ch = SK_BACKSPACE; break;
252 				case 'B': ch = SK_CTL_BACKSPACE; break;
253 				case 'd': ch = SK_DOWN_ARROW; break;
254 				case 'D': ch = SK_PAGE_DOWN; break;
255 				case 'e': ch = SK_END; break;
256 				case 'h': ch = SK_HOME; break;
257 				case 'i': ch = SK_INSERT; break;
258 				case 'l': ch = SK_LEFT_ARROW; break;
259 				case 'L': ch = SK_CTL_LEFT_ARROW; break;
260 				case 'r': ch = SK_RIGHT_ARROW; break;
261 				case 'R': ch = SK_CTL_RIGHT_ARROW; break;
262 				case 't': ch = SK_BACKTAB; break;
263 				case 'u': ch = SK_UP_ARROW; break;
264 				case 'U': ch = SK_PAGE_UP; break;
265 				case 'x': ch = SK_DELETE; break;
266 				case 'X': ch = SK_CTL_DELETE; break;
267 				case '1': ch = SK_F1; break;
268 				default:
269 					parse_error("invalid escape sequence \"\\k%s\"", char_string(buf, *p, 0));
270 					*pp = increment_pointer(p);
271 					return ("");
272 				}
273 				*pp = p+1;
274 				buf[0] = SK_SPECIAL_KEY;
275 				buf[1] = ch;
276 				buf[2] = 6;
277 				buf[3] = 1;
278 				buf[4] = 1;
279 				buf[5] = 1;
280 				buf[6] = '\0';
281 				return (buf);
282 			}
283 			/* FALLTHRU */
284 		default:
285 			/*
286 			 * Backslash followed by any other char
287 			 * just means that char.
288 			 */
289 			*pp = increment_pointer(p);
290 			char_string(buf, *p, 1);
291 			if (xlate && buf[0] == CONTROL('K'))
292 				return tstr_control_k;
293 			return (buf);
294 		}
295 	case '^':
296 		/*
297 		 * Caret means CONTROL.
298 		 */
299 		*pp = increment_pointer(p+1);
300 		char_string(buf, CONTROL(p[1]), 1);
301 		if (xlate && buf[0] == CONTROL('K'))
302 			return tstr_control_k;
303 		return (buf);
304 	}
305 	*pp = increment_pointer(p);
306 	char_string(buf, *p, 1);
307 	if (xlate && buf[0] == CONTROL('K'))
308 		return tstr_control_k;
309 	return (buf);
310 }
311 
312 	static int
313 issp(ch)
314 	char ch;
315 {
316 	return (ch == ' ' || ch == '\t');
317 }
318 
319 /*
320  * Skip leading spaces in a string.
321  */
322 	static char *
323 skipsp(s)
324 	char *s;
325 {
326 	while (issp(*s))
327 		s++;
328 	return (s);
329 }
330 
331 /*
332  * Skip non-space characters in a string.
333  */
334 	static char *
335 skipnsp(s)
336 	char *s;
337 {
338 	while (*s != '\0' && !issp(*s))
339 		s++;
340 	return (s);
341 }
342 
343 /*
344  * Clean up an input line:
345  * strip off the trailing newline & any trailing # comment.
346  */
347 	static char *
348 clean_line(s)
349 	char *s;
350 {
351 	int i;
352 
353 	s = skipsp(s);
354 	for (i = 0;  s[i] != '\0' && s[i] != '\n' && s[i] != '\r';  i++)
355 		if (s[i] == '#' && (i == 0 || s[i-1] != '\\'))
356 			break;
357 	s[i] = '\0';
358 	return (s);
359 }
360 
361 /*
362  * Add a byte to the output command table.
363  */
364 	static void
365 add_cmd_char(c, tables)
366 	int c;
367 	struct lesskey_tables *tables;
368 {
369 	xbuf_add(&tables->currtable->buf, c);
370 }
371 
372 	static void
373 erase_cmd_char(tables)
374 	struct lesskey_tables *tables;
375 {
376 	xbuf_pop(&tables->currtable->buf);
377 }
378 
379 /*
380  * Add a string to the output command table.
381  */
382 	static void
383 add_cmd_str(s, tables)
384 	char *s;
385 	struct lesskey_tables *tables;
386 {
387 	for ( ;  *s != '\0';  s++)
388 		add_cmd_char(*s, tables);
389 }
390 
391 /*
392  * Does a given version number match the running version?
393  * Operator compares the running version to the given version.
394  */
395 	static int
396 match_version(op, ver)
397 	char op;
398 	int ver;
399 {
400 	switch (op)
401 	{
402 	case '>': return less_version > ver;
403 	case '<': return less_version < ver;
404 	case '+': return less_version >= ver;
405 	case '-': return less_version <= ver;
406 	case '=': return less_version == ver;
407 	case '!': return less_version != ver;
408 	default: return 0; /* cannot happen */
409 	}
410 }
411 
412 /*
413  * Handle a #version line.
414  * If the version matches, return the part of the line that should be executed.
415  * Otherwise, return NULL.
416  */
417 	static char *
418 version_line(s, tables)
419 	char *s;
420 	struct lesskey_tables *tables;
421 {
422 	char op;
423 	int ver;
424 	char *e;
425 	char buf[CHAR_STRING_LEN];
426 
427 	s += strlen("#version");
428 	s = skipsp(s);
429 	op = *s++;
430 	/* Simplify 2-char op to one char. */
431 	switch (op)
432 	{
433 	case '<': if (*s == '=') { s++; op = '-'; } break;
434 	case '>': if (*s == '=') { s++; op = '+'; } break;
435 	case '=': if (*s == '=') { s++; } break;
436 	case '!': if (*s == '=') { s++; } break;
437 	default:
438 		parse_error("invalid operator '%s' in #version line", char_string(buf, op, 0));
439 		return (NULL);
440 	}
441 	s = skipsp(s);
442 	ver = lstrtoi(s, &e);
443 	if (e == s)
444 	{
445 		parse_error("non-numeric version number in #version line", "");
446 		return (NULL);
447 	}
448 	if (!match_version(op, ver))
449 		return (NULL);
450 	return (e);
451 }
452 
453 /*
454  * See if we have a special "control" line.
455  */
456 	static char *
457 control_line(s, tables)
458 	char *s;
459 	struct lesskey_tables *tables;
460 {
461 #define PREFIX(str,pat) (strncmp(str,pat,strlen(pat)) == 0)
462 
463 	if (PREFIX(s, "#line-edit"))
464 	{
465 		tables->currtable = &tables->edittable;
466 		return (NULL);
467 	}
468 	if (PREFIX(s, "#command"))
469 	{
470 		tables->currtable = &tables->cmdtable;
471 		return (NULL);
472 	}
473 	if (PREFIX(s, "#env"))
474 	{
475 		tables->currtable = &tables->vartable;
476 		return (NULL);
477 	}
478 	if (PREFIX(s, "#stop"))
479 	{
480 		add_cmd_char('\0', tables);
481 		add_cmd_char(A_END_LIST, tables);
482 		return (NULL);
483 	}
484 	if (PREFIX(s, "#version"))
485 	{
486 		return (version_line(s, tables));
487 	}
488 	return (s);
489 }
490 
491 /*
492  * Find an action, given the name of the action.
493  */
494 	static int
495 findaction(actname, tables)
496 	char *actname;
497 	struct lesskey_tables *tables;
498 {
499 	int i;
500 
501 	for (i = 0;  tables->currtable->names[i].cn_name != NULL;  i++)
502 		if (strcmp(tables->currtable->names[i].cn_name, actname) == 0)
503 			return (tables->currtable->names[i].cn_action);
504 	parse_error("unknown action: \"%s\"", actname);
505 	return (A_INVALID);
506 }
507 
508 /*
509  * Parse a line describing one key binding, of the form
510  *  KEY ACTION [EXTRA]
511  * where KEY is the user key sequence, ACTION is the
512  * resulting less action, and EXTRA is an "extra" user
513  * key sequence injected after the action.
514  */
515 	static void
516 parse_cmdline(p, tables)
517 	char *p;
518 	struct lesskey_tables *tables;
519 {
520 	char *actname;
521 	int action;
522 	char *s;
523 	char c;
524 
525 	/*
526 	 * Parse the command string and store it in the current table.
527 	 */
528 	do
529 	{
530 		s = tstr(&p, 1);
531 		add_cmd_str(s, tables);
532 	} while (*p != '\0' && !issp(*p));
533 	/*
534 	 * Terminate the command string with a null byte.
535 	 */
536 	add_cmd_char('\0', tables);
537 
538 	/*
539 	 * Skip white space between the command string
540 	 * and the action name.
541 	 * Terminate the action name with a null byte.
542 	 */
543 	p = skipsp(p);
544 	if (*p == '\0')
545 	{
546 		parse_error("missing action", "");
547 		return;
548 	}
549 	actname = p;
550 	p = skipnsp(p);
551 	c = *p;
552 	*p = '\0';
553 
554 	/*
555 	 * Parse the action name and store it in the current table.
556 	 */
557 	action = findaction(actname, tables);
558 
559 	/*
560 	 * See if an extra string follows the action name.
561 	 */
562 	*p = c;
563 	p = skipsp(p);
564 	if (*p == '\0')
565 	{
566 		add_cmd_char(action, tables);
567 	} else
568 	{
569 		/*
570 		 * OR the special value A_EXTRA into the action byte.
571 		 * Put the extra string after the action byte.
572 		 */
573 		add_cmd_char(action | A_EXTRA, tables);
574 		while (*p != '\0')
575 			add_cmd_str(tstr(&p, 0), tables);
576 		add_cmd_char('\0', tables);
577 	}
578 }
579 
580 /*
581  * Parse a variable definition line, of the form
582  *  NAME = VALUE
583  */
584 	static void
585 parse_varline(line, tables)
586 	char *line;
587 	struct lesskey_tables *tables;
588 {
589 	char *s;
590 	char *p = line;
591 	char *eq;
592 
593 	eq = strchr(line, '=');
594 	if (eq != NULL && eq > line && eq[-1] == '+')
595 	{
596 		/*
597 		 * Rather ugly way of handling a += line.
598 		 * {{ Note that we ignore the variable name and
599 		 *    just append to the previously defined variable. }}
600 		 */
601 		erase_cmd_char(tables); /* backspace over the final null */
602 		p = eq+1;
603 	} else
604 	{
605 		do
606 		{
607 			s = tstr(&p, 0);
608 			add_cmd_str(s, tables);
609 		} while (*p != '\0' && !issp(*p) && *p != '=');
610 		/*
611 		 * Terminate the variable name with a null byte.
612 		 */
613 		add_cmd_char('\0', tables);
614 		p = skipsp(p);
615 		if (*p++ != '=')
616 		{
617 			parse_error("missing = in variable definition", "");
618 			return;
619 		}
620 		add_cmd_char(EV_OK|A_EXTRA, tables);
621 	}
622 	p = skipsp(p);
623 	while (*p != '\0')
624 	{
625 		s = tstr(&p, 0);
626 		add_cmd_str(s, tables);
627 	}
628 	add_cmd_char('\0', tables);
629 }
630 
631 /*
632  * Parse a line from the lesskey file.
633  */
634 	static void
635 parse_line(line, tables)
636 	char *line;
637 	struct lesskey_tables *tables;
638 {
639 	char *p;
640 
641 	/*
642 	 * See if it is a control line.
643 	 */
644 	p = control_line(line, tables);
645 	if (p == NULL)
646 		return;
647 	/*
648 	 * Skip leading white space.
649 	 * Replace the final newline with a null byte.
650 	 * Ignore blank lines and comments.
651 	 */
652 	p = clean_line(p);
653 	if (*p == '\0')
654 		return;
655 
656 	if (tables->currtable->is_var)
657 		parse_varline(p, tables);
658 	else
659 		parse_cmdline(p, tables);
660 }
661 
662 /*
663  * Parse a lesskey source file and store result in tables.
664  */
665 	int
666 parse_lesskey(infile, tables)
667 	char *infile;
668 	struct lesskey_tables *tables;
669 {
670 	FILE *desc;
671 	char line[1024];
672 
673 	if (infile == NULL)
674 		infile = homefile(DEF_LESSKEYINFILE);
675 	lesskey_file = infile;
676 
677 	init_tables(tables);
678 	errors = 0;
679 	linenum = 0;
680 	if (less_version == 0)
681 		less_version = lstrtoi(version, NULL);
682 
683 	/*
684 	 * Open the input file.
685 	 */
686 	if (strcmp(infile, "-") == 0)
687 		desc = stdin;
688 	else if ((desc = fopen(infile, "r")) == NULL)
689 	{
690 		/* parse_error("cannot open lesskey file %s", infile); */
691 		return (-1);
692 	}
693 
694 	/*
695 	 * Read and parse the input file, one line at a time.
696 	 */
697 	while (fgets(line, sizeof(line), desc) != NULL)
698 	{
699 		++linenum;
700 		parse_line(line, tables);
701 	}
702 	fclose(desc);
703 	return (errors);
704 }
705