xref: /freebsd/contrib/less/decode.c (revision 7fdf597e96a02165cfe22ff357b857d5fa15ed8a)
1 /*
2  * Copyright (C) 1984-2024  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  * Routines to decode user commands.
13  *
14  * This is all table driven.
15  * A command table is a sequence of command descriptors.
16  * Each command descriptor is a sequence of bytes with the following format:
17  *     <c1><c2>...<cN><0><action>
18  * The characters c1,c2,...,cN are the command string; that is,
19  * the characters which the user must type.
20  * It is terminated by a null <0> byte.
21  * The byte after the null byte is the action code associated
22  * with the command string.
23  * If an action byte is OR-ed with A_EXTRA, this indicates
24  * that the option byte is followed by an extra string.
25  *
26  * There may be many command tables.
27  * The first (default) table is built-in.
28  * Other tables are read in from "lesskey" files.
29  * All the tables are linked together and are searched in order.
30  */
31 
32 #include "less.h"
33 #include "cmd.h"
34 #include "lesskey.h"
35 
36 extern int erase_char, erase2_char, kill_char;
37 extern int mousecap;
38 extern int sc_height;
39 
40 #if USERFILE
41 /* "content" is lesskey source, never binary. */
42 static void add_content_table(int (*call_lesskey)(constant char *, lbool), constant char *envname, lbool sysvar);
43 static int add_hometable(int (*call_lesskey)(constant char *, lbool), constant char *envname, constant char *def_filename, lbool sysvar);
44 #endif /* USERFILE */
45 
46 #define SK(k) \
47 	SK_SPECIAL_KEY, (k), 6, 1, 1, 1
48 /*
49  * Command table is ordered roughly according to expected
50  * frequency of use, so the common commands are near the beginning.
51  */
52 
53 static unsigned char cmdtable[] =
54 {
55 	'\r',0,                         A_F_LINE,
56 	'\n',0,                         A_F_LINE,
57 	'e',0,                          A_F_LINE,
58 	'j',0,                          A_F_LINE,
59 	SK(SK_DOWN_ARROW),0,            A_F_LINE,
60 	CONTROL('E'),0,                 A_F_LINE,
61 	CONTROL('N'),0,                 A_F_LINE,
62 	'k',0,                          A_B_LINE,
63 	'y',0,                          A_B_LINE,
64 	CONTROL('Y'),0,                 A_B_LINE,
65 	SK(SK_CONTROL_K),0,             A_B_LINE,
66 	CONTROL('P'),0,                 A_B_LINE,
67 	SK(SK_UP_ARROW),0,              A_B_LINE,
68 	'J',0,                          A_FF_LINE,
69 	'K',0,                          A_BF_LINE,
70 	'Y',0,                          A_BF_LINE,
71 	'd',0,                          A_F_SCROLL,
72 	CONTROL('D'),0,                 A_F_SCROLL,
73 	'u',0,                          A_B_SCROLL,
74 	CONTROL('U'),0,                 A_B_SCROLL,
75 	ESC,'[','M',0,                  A_X11MOUSE_IN,
76 	ESC,'[','<',0,                  A_X116MOUSE_IN,
77 	' ',0,                          A_F_SCREEN,
78 	'f',0,                          A_F_SCREEN,
79 	CONTROL('F'),0,                 A_F_SCREEN,
80 	CONTROL('V'),0,                 A_F_SCREEN,
81 	SK(SK_PAGE_DOWN),0,             A_F_SCREEN,
82 	'b',0,                          A_B_SCREEN,
83 	CONTROL('B'),0,                 A_B_SCREEN,
84 	ESC,'v',0,                      A_B_SCREEN,
85 	SK(SK_PAGE_UP),0,               A_B_SCREEN,
86 	'z',0,                          A_F_WINDOW,
87 	'w',0,                          A_B_WINDOW,
88 	ESC,' ',0,                      A_FF_SCREEN,
89 	'F',0,                          A_F_FOREVER,
90 	ESC,'F',0,                      A_F_UNTIL_HILITE,
91 	'R',0,                          A_FREPAINT,
92 	'r',0,                          A_REPAINT,
93 	CONTROL('R'),0,                 A_REPAINT,
94 	CONTROL('L'),0,                 A_REPAINT,
95 	ESC,'u',0,                      A_UNDO_SEARCH,
96 	ESC,'U',0,                      A_CLR_SEARCH,
97 	'g',0,                          A_GOLINE,
98 	SK(SK_HOME),0,                  A_GOLINE,
99 	'<',0,                          A_GOLINE,
100 	ESC,'<',0,                      A_GOLINE,
101 	'p',0,                          A_PERCENT,
102 	'%',0,                          A_PERCENT,
103 	ESC,'(',0,                      A_LSHIFT,
104 	ESC,')',0,                      A_RSHIFT,
105 	ESC,'{',0,                      A_LLSHIFT,
106 	ESC,'}',0,                      A_RRSHIFT,
107 	SK(SK_RIGHT_ARROW),0,           A_RSHIFT,
108 	SK(SK_LEFT_ARROW),0,            A_LSHIFT,
109 	SK(SK_CTL_RIGHT_ARROW),0,       A_RRSHIFT,
110 	SK(SK_CTL_LEFT_ARROW),0,        A_LLSHIFT,
111 	'{',0,                          A_F_BRACKET|A_EXTRA,        '{','}',0,
112 	'}',0,                          A_B_BRACKET|A_EXTRA,        '{','}',0,
113 	'(',0,                          A_F_BRACKET|A_EXTRA,        '(',')',0,
114 	')',0,                          A_B_BRACKET|A_EXTRA,        '(',')',0,
115 	'[',0,                          A_F_BRACKET|A_EXTRA,        '[',']',0,
116 	']',0,                          A_B_BRACKET|A_EXTRA,        '[',']',0,
117 	ESC,CONTROL('F'),0,             A_F_BRACKET,
118 	ESC,CONTROL('B'),0,             A_B_BRACKET,
119 	'G',0,                          A_GOEND,
120 	ESC,'G',0,                      A_GOEND_BUF,
121 	ESC,'>',0,                      A_GOEND,
122 	'>',0,                          A_GOEND,
123 	SK(SK_END),0,                   A_GOEND,
124 	'P',0,                          A_GOPOS,
125 
126 	'0',0,                          A_DIGIT,
127 	'1',0,                          A_DIGIT,
128 	'2',0,                          A_DIGIT,
129 	'3',0,                          A_DIGIT,
130 	'4',0,                          A_DIGIT,
131 	'5',0,                          A_DIGIT,
132 	'6',0,                          A_DIGIT,
133 	'7',0,                          A_DIGIT,
134 	'8',0,                          A_DIGIT,
135 	'9',0,                          A_DIGIT,
136 	'.',0,                          A_DIGIT,
137 
138 	'=',0,                          A_STAT,
139 	CONTROL('G'),0,                 A_STAT,
140 	':','f',0,                      A_STAT,
141 	'/',0,                          A_F_SEARCH,
142 	'?',0,                          A_B_SEARCH,
143 	ESC,'/',0,                      A_F_SEARCH|A_EXTRA,        '*',0,
144 	ESC,'?',0,                      A_B_SEARCH|A_EXTRA,        '*',0,
145 	'n',0,                          A_AGAIN_SEARCH,
146 	ESC,'n',0,                      A_T_AGAIN_SEARCH,
147 	'N',0,                          A_REVERSE_SEARCH,
148 	ESC,'N',0,                      A_T_REVERSE_SEARCH,
149 	'&',0,                          A_FILTER,
150 	'm',0,                          A_SETMARK,
151 	'M',0,                          A_SETMARKBOT,
152 	ESC,'m',0,                      A_CLRMARK,
153 	'\'',0,                         A_GOMARK,
154 	CONTROL('X'),CONTROL('X'),0,    A_GOMARK,
155 	'E',0,                          A_EXAMINE,
156 	':','e',0,                      A_EXAMINE,
157 	CONTROL('X'),CONTROL('V'),0,    A_EXAMINE,
158 	':','n',0,                      A_NEXT_FILE,
159 	':','p',0,                      A_PREV_FILE,
160 	CONTROL('O'),CONTROL('N'),0,    A_OSC8_F_SEARCH,
161 	CONTROL('O'),'n',0,             A_OSC8_F_SEARCH,
162 	CONTROL('O'),CONTROL('P'),0,    A_OSC8_B_SEARCH,
163 	CONTROL('O'),'p',0,             A_OSC8_B_SEARCH,
164 	CONTROL('O'),CONTROL('O'),0,    A_OSC8_OPEN,
165 	CONTROL('O'),'o',0,             A_OSC8_OPEN,
166 	CONTROL('O'),CONTROL('L'),0,    A_OSC8_JUMP,
167 	CONTROL('O'),'l',0,             A_OSC8_JUMP,
168 	't',0,                          A_NEXT_TAG,
169 	'T',0,                          A_PREV_TAG,
170 	':','x',0,                      A_INDEX_FILE,
171 	':','d',0,                      A_REMOVE_FILE,
172 	'-',0,                          A_OPT_TOGGLE,
173 	':','t',0,                      A_OPT_TOGGLE|A_EXTRA,        't',0,
174 	's',0,                          A_OPT_TOGGLE|A_EXTRA,        'o',0,
175 	'_',0,                          A_DISP_OPTION,
176 	'|',0,                          A_PIPE,
177 	'v',0,                          A_VISUAL,
178 	'!',0,                          A_SHELL,
179 	'#',0,                          A_PSHELL,
180 	'+',0,                          A_FIRSTCMD,
181 
182 	'H',0,                          A_HELP,
183 	'h',0,                          A_HELP,
184 	SK(SK_F1),0,                    A_HELP,
185 	'V',0,                          A_VERSION,
186 	'q',0,                          A_QUIT,
187 	'Q',0,                          A_QUIT,
188 	':','q',0,                      A_QUIT,
189 	':','Q',0,                      A_QUIT,
190 	'Z','Z',0,                      A_QUIT
191 };
192 
193 static unsigned char edittable[] =
194 {
195 	'\t',0,                         EC_F_COMPLETE,  /* TAB */
196 	'\17',0,                        EC_B_COMPLETE,  /* BACKTAB */
197 	SK(SK_BACKTAB),0,               EC_B_COMPLETE,  /* BACKTAB */
198 	ESC,'\t',0,                     EC_B_COMPLETE,  /* ESC TAB */
199 	CONTROL('L'),0,                 EC_EXPAND,      /* CTRL-L */
200 	CONTROL('V'),0,                 EC_LITERAL,     /* BACKSLASH */
201 	CONTROL('A'),0,                 EC_LITERAL,     /* BACKSLASH */
202 	ESC,'l',0,                      EC_RIGHT,       /* ESC l */
203 	SK(SK_RIGHT_ARROW),0,           EC_RIGHT,       /* RIGHTARROW */
204 	ESC,'h',0,                      EC_LEFT,        /* ESC h */
205 	SK(SK_LEFT_ARROW),0,            EC_LEFT,        /* LEFTARROW */
206 	ESC,'b',0,                      EC_W_LEFT,      /* ESC b */
207 	ESC,SK(SK_LEFT_ARROW),0,        EC_W_LEFT,      /* ESC LEFTARROW */
208 	SK(SK_CTL_LEFT_ARROW),0,        EC_W_LEFT,      /* CTRL-LEFTARROW */
209 	ESC,'w',0,                      EC_W_RIGHT,     /* ESC w */
210 	ESC,SK(SK_RIGHT_ARROW),0,       EC_W_RIGHT,     /* ESC RIGHTARROW */
211 	SK(SK_CTL_RIGHT_ARROW),0,       EC_W_RIGHT,     /* CTRL-RIGHTARROW */
212 	ESC,'i',0,                      EC_INSERT,      /* ESC i */
213 	SK(SK_INSERT),0,                EC_INSERT,      /* INSERT */
214 	ESC,'x',0,                      EC_DELETE,      /* ESC x */
215 	SK(SK_DELETE),0,                EC_DELETE,      /* DELETE */
216 	ESC,'X',0,                      EC_W_DELETE,    /* ESC X */
217 	ESC,SK(SK_DELETE),0,            EC_W_DELETE,    /* ESC DELETE */
218 	SK(SK_CTL_DELETE),0,            EC_W_DELETE,    /* CTRL-DELETE */
219 	SK(SK_CTL_BACKSPACE),0,         EC_W_BACKSPACE, /* CTRL-BACKSPACE */
220 	ESC,SK(SK_BACKSPACE),0,         EC_W_BACKSPACE, /* ESC BACKSPACE */
221 	ESC,'0',0,                      EC_HOME,        /* ESC 0 */
222 	SK(SK_HOME),0,                  EC_HOME,        /* HOME */
223 	ESC,'$',0,                      EC_END,         /* ESC $ */
224 	SK(SK_END),0,                   EC_END,         /* END */
225 	ESC,'k',0,                      EC_UP,          /* ESC k */
226 	SK(SK_UP_ARROW),0,              EC_UP,          /* UPARROW */
227 	ESC,'j',0,                      EC_DOWN,        /* ESC j */
228 	SK(SK_DOWN_ARROW),0,            EC_DOWN,        /* DOWNARROW */
229 	CONTROL('G'),0,                 EC_ABORT,       /* CTRL-G */
230 	ESC,'[','M',0,                  EC_X11MOUSE,    /* X11 mouse report */
231 	ESC,'[','<',0,                  EC_X116MOUSE,   /* X11 1006 mouse report */
232 };
233 
234 static unsigned char dflt_vartable[] =
235 {
236 	'L','E','S','S','_','O','S','C','8','_','m','a','n', 0, EV_OK|A_EXTRA,
237 		/* echo '%o' | sed -e "s,^man\:\\([^(]*\\)( *\\([^)]*\\)\.*,-man '\\2' '\\1'," -e"t X" -e"s,\.*,-echo Invalid man link," -e"\: X" */
238 		'e','c','h','o',' ','\'','%','o','\'',' ','|',' ','s','e','d',' ','-','e',' ','"','s',',','^','m','a','n','\\',':','\\','\\','(','[','^','(',']','*','\\','\\',')','(',' ','*','\\','\\','(','[','^',')',']','*','\\','\\',')','\\','.','*',',','-','m','a','n',' ','\'','\\','\\','2','\'',' ','\'','\\','\\','1','\'',',','"',' ','-','e','"','t',' ','X','"',' ','-','e','"','s',',','\\','.','*',',','-','e','c','h','o',' ','I','n','v','a','l','i','d',' ','m','a','n',' ','l','i','n','k',',','"',' ','-','e','"','\\',':',' ','X','"',
239 		0,
240 
241 	'L','E','S','S','_','O','S','C','8','_','f','i','l','e', 0, EV_OK|A_EXTRA,
242 		/* eval `echo '%o' | sed -e "s,^file://\\([^/]*\\)\\(.*\\),_H=\\1;_P=\\2;_E=0," -e"t X" -e"s,.*,_E=1," -e": X"`; if [ "$_E" = 1 ]; then echo -echo Invalid file link; elif [ -z "$_H" -o "$_H" = localhost -o "$_H" = $HOSTNAME ]; then echo ":e $_P"; else echo -echo Cannot open remote file on "$_H"; fi */
243 		'e','v','a','l',' ','`','e','c','h','o',' ','\'','%','o','\'',' ','|',' ','s','e','d',' ','-','e',' ','"','s',',','^','f','i','l','e','\\',':','/','/','\\','\\','(','[','^','/',']','*','\\','\\',')','\\','\\','(','\\','.','*','\\','\\',')',',','_','H','=','\\','\\','1',';','_','P','=','\\','\\','2',';','_','E','=','0',',','"',' ','-','e','"','t',' ','X','"',' ','-','e','"','s',',','\\','.','*',',','_','E','=','1',',','"',' ','-','e','"','\\',':',' ','X','"','`',';',' ','i','f',' ','[',' ','"','$','_','E','"',' ','=',' ','1',' ',']',';',' ','t','h','e','n',' ','e','c','h','o',' ','-','e','c','h','o',' ','I','n','v','a','l','i','d',' ','f','i','l','e',' ','l','i','n','k',';',' ','e','l','i','f',' ','[',' ','-','z',' ','"','$','_','H','"',' ','-','o',' ','"','$','_','H','"',' ','=',' ','l','o','c','a','l','h','o','s','t',' ','-','o',' ','"','$','_','H','"',' ','=',' ','$','H','O','S','T','N','A','M','E',' ',']',';',' ','t','h','e','n',' ','e','c','h','o',' ','"','\\',':','e',' ','$','_','P','"',';',' ','e','l','s','e',' ','e','c','h','o',' ','-','e','c','h','o',' ','C','a','n','n','o','t',' ','o','p','e','n',' ','r','e','m','o','t','e',' ','f','i','l','e',' ','o','n',' ','"','$','_','H','"',';',' ','f','i',
244 		0,
245 };
246 
247 /*
248  * Structure to support a list of command tables.
249  */
250 struct tablelist
251 {
252 	struct tablelist *t_next;
253 	unsigned char *t_start;
254 	unsigned char *t_end;
255 };
256 
257 /*
258  * List of command tables and list of line-edit tables.
259  */
260 static struct tablelist *list_fcmd_tables = NULL;
261 static struct tablelist *list_ecmd_tables = NULL;
262 static struct tablelist *list_var_tables = NULL;
263 static struct tablelist *list_sysvar_tables = NULL;
264 
265 
266 /*
267  * Expand special key abbreviations in a command table.
268  */
269 static void expand_special_keys(unsigned char *table, size_t len)
270 {
271 	unsigned char *fm;
272 	unsigned char *to;
273 	int a;
274 	constant char *repl;
275 	size_t klen;
276 
277 	for (fm = table;  fm < table + len; )
278 	{
279 		/*
280 		 * Rewrite each command in the table with any
281 		 * special key abbreviations expanded.
282 		 */
283 		for (to = fm;  *fm != '\0'; )
284 		{
285 			if (*fm != SK_SPECIAL_KEY)
286 			{
287 				*to++ = *fm++;
288 				continue;
289 			}
290 			/*
291 			 * After SK_SPECIAL_KEY, next byte is the type
292 			 * of special key (one of the SK_* constants),
293 			 * and the byte after that is the number of bytes,
294 			 * N, reserved by the abbreviation (including the
295 			 * SK_SPECIAL_KEY and key type bytes).
296 			 * Replace all N bytes with the actual bytes
297 			 * output by the special key on this terminal.
298 			 */
299 			repl = special_key_str(fm[1]);
300 			klen = fm[2] & 0377;
301 			fm += klen;
302 			if (repl == NULL || strlen(repl) > klen)
303 				repl = "\377";
304 			while (*repl != '\0')
305 				*to++ = (unsigned char) *repl++; /*{{type-issue}}*/
306 		}
307 		*to++ = '\0';
308 		/*
309 		 * Fill any unused bytes between end of command and
310 		 * the action byte with A_SKIP.
311 		 */
312 		while (to <= fm)
313 			*to++ = A_SKIP;
314 		fm++;
315 		a = *fm++ & 0377;
316 		if (a & A_EXTRA)
317 		{
318 			while (*fm++ != '\0')
319 				continue;
320 		}
321 	}
322 }
323 
324 /*
325  * Expand special key abbreviations in a list of command tables.
326  */
327 static void expand_cmd_table(struct tablelist *tlist)
328 {
329 	struct tablelist *t;
330 	for (t = tlist;  t != NULL;  t = t->t_next)
331 	{
332 		expand_special_keys(t->t_start, ptr_diff(t->t_end, t->t_start));
333 	}
334 }
335 
336 /*
337  * Expand special key abbreviations in all command tables.
338  */
339 public void expand_cmd_tables(void)
340 {
341 	expand_cmd_table(list_fcmd_tables);
342 	expand_cmd_table(list_ecmd_tables);
343 	expand_cmd_table(list_var_tables);
344 	expand_cmd_table(list_sysvar_tables);
345 }
346 
347 /*
348  * Initialize the command lists.
349  */
350 public void init_cmds(void)
351 {
352 	/*
353 	 * Add the default command tables.
354 	 */
355 	add_fcmd_table(cmdtable, sizeof(cmdtable));
356 	add_ecmd_table(edittable, sizeof(edittable));
357 	add_sysvar_table(dflt_vartable, sizeof(dflt_vartable));
358 #if USERFILE
359 #ifdef BINDIR /* For backwards compatibility */
360 	/* Try to add tables in the OLD system lesskey file. */
361 	add_hometable(lesskey, NULL, BINDIR "/.sysless", TRUE);
362 #endif
363 	/*
364 	 * Try to load lesskey source file or binary file.
365 	 * If the source file succeeds, don't load binary file.
366 	 * The binary file is likely to have been generated from
367 	 * a (possibly out of date) copy of the src file,
368 	 * so loading it is at best redundant.
369 	 */
370 	/*
371 	 * Try to add tables in system lesskey src file.
372 	 */
373 #if HAVE_LESSKEYSRC
374 	if (add_hometable(lesskey_src, "LESSKEYIN_SYSTEM", LESSKEYINFILE_SYS, TRUE) != 0)
375 #endif
376 	{
377 		/*
378 		 * Try to add the tables in the system lesskey binary file.
379 		 */
380 		add_hometable(lesskey, "LESSKEY_SYSTEM", LESSKEYFILE_SYS, TRUE);
381 	}
382 	/*
383 	 * Try to add tables in the lesskey src file "$HOME/.lesskey".
384 	 */
385 #if HAVE_LESSKEYSRC
386 	if (add_hometable(lesskey_src, "LESSKEYIN", DEF_LESSKEYINFILE, FALSE) != 0)
387 #endif
388 	{
389 		/*
390 		 * Try to add the tables in the standard lesskey binary file "$HOME/.less".
391 		 */
392 		add_hometable(lesskey, "LESSKEY", LESSKEYFILE, FALSE);
393 	}
394 
395 	add_content_table(lesskey_content, "LESSKEY_CONTENT_SYSTEM", TRUE);
396 	add_content_table(lesskey_content, "LESSKEY_CONTENT", FALSE);
397 #endif /* USERFILE */
398 }
399 
400 /*
401  * Add a command table.
402  */
403 static int add_cmd_table(struct tablelist **tlist, unsigned char *buf, size_t len)
404 {
405 	struct tablelist *t;
406 
407 	if (len == 0)
408 		return (0);
409 	/*
410 	 * Allocate a tablelist structure, initialize it,
411 	 * and link it into the list of tables.
412 	 */
413 	if ((t = (struct tablelist *)
414 			calloc(1, sizeof(struct tablelist))) == NULL)
415 	{
416 		return (-1);
417 	}
418 	t->t_start = buf;
419 	t->t_end = buf + len;
420 	t->t_next = NULL;
421 	if (*tlist == NULL)
422 		*tlist = t;
423 	else
424 	{
425 		struct tablelist *e;
426 		for (e = *tlist;  e->t_next != NULL;  e = e->t_next)
427 			continue;
428 		e->t_next = t;
429 	}
430 	return (0);
431 }
432 
433 /*
434  * Remove the last command table in a list.
435  */
436 static void pop_cmd_table(struct tablelist **tlist)
437 {
438 	struct tablelist *t;
439 	if (*tlist == NULL)
440 		return;
441 	if ((*tlist)->t_next == NULL)
442 	{
443 		t = *tlist;
444 		*tlist = NULL;
445 	} else
446 	{
447 		struct tablelist *e;
448 		for (e = *tlist;  e->t_next->t_next != NULL;  e = e->t_next)
449 			continue;
450 		t = e->t_next;
451 		e->t_next = NULL;
452 	}
453 	free(t);
454 }
455 
456 /*
457  * Add a command table.
458  */
459 public void add_fcmd_table(unsigned char *buf, size_t len)
460 {
461 	if (add_cmd_table(&list_fcmd_tables, buf, len) < 0)
462 		error("Warning: some commands disabled", NULL_PARG);
463 }
464 
465 /*
466  * Add an editing command table.
467  */
468 public void add_ecmd_table(unsigned char *buf, size_t len)
469 {
470 	if (add_cmd_table(&list_ecmd_tables, buf, len) < 0)
471 		error("Warning: some edit commands disabled", NULL_PARG);
472 }
473 
474 /*
475  * Add an environment variable table.
476  */
477 static void add_var_table(struct tablelist **tlist, unsigned char *buf, size_t len)
478 {
479 	struct xbuffer xbuf;
480 
481 	xbuf_init(&xbuf);
482 	expand_evars((char*)buf, len, &xbuf); /*{{unsigned-issue}}*/
483 	/* {{ We leak the table in buf. expand_evars scribbled in it so it's useless anyway. }} */
484 	if (add_cmd_table(tlist, xbuf.data, xbuf.end) < 0)
485 		error("Warning: environment variables from lesskey file unavailable", NULL_PARG);
486 }
487 
488 public void add_uvar_table(unsigned char *buf, size_t len)
489 {
490 	add_var_table(&list_var_tables, buf, len);
491 }
492 
493 public void add_sysvar_table(unsigned char *buf, size_t len)
494 {
495 	add_var_table(&list_sysvar_tables, buf, len);
496 }
497 
498 /*
499  * Return action for a mouse wheel down event.
500  */
501 static int mouse_wheel_down(void)
502 {
503 	return ((mousecap == OPT_ONPLUS) ? A_B_MOUSE : A_F_MOUSE);
504 }
505 
506 /*
507  * Return action for a mouse wheel up event.
508  */
509 static int mouse_wheel_up(void)
510 {
511 	return ((mousecap == OPT_ONPLUS) ? A_F_MOUSE : A_B_MOUSE);
512 }
513 
514 /*
515  * Return action for the left mouse button trigger.
516  */
517 static int mouse_button_left(int x, int y)
518 {
519 	/*
520 	 * {{ It would be better to return an action and then do this
521 	 *    in commands() but it's nontrivial to pass y to it. }}
522 	 */
523 #if OSC8_LINK
524 	if (osc8_click(y, x))
525 		return (A_NOACTION);
526 #else
527 	(void) x;
528 #endif /* OSC8_LINK */
529 	if (y < sc_height-1)
530 	{
531 		setmark('#', y);
532 		screen_trashed();
533 	}
534 	return (A_NOACTION);
535 }
536 
537 /*
538  * Return action for the right mouse button trigger.
539  */
540 static int mouse_button_right(int x, int y)
541 {
542 	(void) x;
543 	/*
544 	 * {{ unlike mouse_button_left, we could return an action,
545 	 *    but keep it near mouse_button_left for readability. }}
546 	 */
547 	if (y < sc_height-1)
548 	{
549 		gomark('#');
550 		screen_trashed();
551 	}
552 	return (A_NOACTION);
553 }
554 
555 /*
556  * Read a decimal integer. Return the integer and set *pterm to the terminating char.
557  */
558 static int getcc_int(char *pterm)
559 {
560 	int num = 0;
561 	int digits = 0;
562 	for (;;)
563 	{
564 		char ch = getcc();
565 		if (ch < '0' || ch > '9')
566 		{
567 			if (pterm != NULL) *pterm = ch;
568 			if (digits == 0)
569 				return (-1);
570 			return (num);
571 		}
572 		if (ckd_mul(&num, num, 10) || ckd_add(&num, num, ch - '0'))
573 			return -1;
574 		++digits;
575 	}
576 }
577 
578 /*
579  * Read suffix of mouse input and return the action to take.
580  * The prefix ("\e[M") has already been read.
581  */
582 static int x11mouse_action(int skip)
583 {
584 	static int prev_b = X11MOUSE_BUTTON_REL;
585 	int b = getcc() - X11MOUSE_OFFSET;
586 	int x = getcc() - X11MOUSE_OFFSET-1;
587 	int y = getcc() - X11MOUSE_OFFSET-1;
588 	if (skip)
589 		return (A_NOACTION);
590 	switch (b) {
591 	default:
592 		prev_b = b;
593 		return (A_NOACTION);
594 	case X11MOUSE_WHEEL_DOWN:
595 		return mouse_wheel_down();
596 	case X11MOUSE_WHEEL_UP:
597 		return mouse_wheel_up();
598 	case X11MOUSE_BUTTON_REL:
599 		/* to trigger on button-up, we check the last button-down */
600 		switch (prev_b) {
601 		case X11MOUSE_BUTTON1:
602 			return mouse_button_left(x, y);
603 		/* is BUTTON2 the rightmost with 2-buttons mouse? */
604 		case X11MOUSE_BUTTON2:
605 		case X11MOUSE_BUTTON3:
606 			return mouse_button_right(x, y);
607 		}
608 		return (A_NOACTION);
609 	}
610 }
611 
612 /*
613  * Read suffix of mouse input and return the action to take.
614  * The prefix ("\e[<") has already been read.
615  */
616 static int x116mouse_action(int skip)
617 {
618 	char ch;
619 	int x, y;
620 	int b = getcc_int(&ch);
621 	if (b < 0 || ch != ';') return (A_NOACTION);
622 	x = getcc_int(&ch) - 1;
623 	if (x < 0 || ch != ';') return (A_NOACTION);
624 	y = getcc_int(&ch) - 1;
625 	if (y < 0) return (A_NOACTION);
626 	if (skip)
627 		return (A_NOACTION);
628 	switch (b) {
629 	case X11MOUSE_WHEEL_DOWN:
630 		return mouse_wheel_down();
631 	case X11MOUSE_WHEEL_UP:
632 		return mouse_wheel_up();
633 	case X11MOUSE_BUTTON1:
634 		if (ch != 'm') return (A_NOACTION);
635 		return mouse_button_left(x, y);
636 	default:
637 		if (ch != 'm') return (A_NOACTION);
638 		/* any other button release */
639 		return mouse_button_right(x, y);
640 	}
641 }
642 
643 /*
644  * Search a single command table for the command string in cmd.
645  */
646 static int cmd_search(constant char *cmd, constant char *table, constant char *endtable, constant char **sp)
647 {
648 	constant char *p;
649 	constant char *q;
650 	int a = A_INVALID;
651 
652 	*sp = NULL;
653 	for (p = table, q = cmd;  p < endtable;  p++, q++)
654 	{
655 		if (*p == *q)
656 		{
657 			/*
658 			 * Current characters match.
659 			 * If we're at the end of the string, we've found it.
660 			 * Return the action code, which is the character
661 			 * after the null at the end of the string
662 			 * in the command table.
663 			 */
664 			if (*p == '\0')
665 			{
666 				a = *++p & 0377;
667 				while (a == A_SKIP)
668 					a = *++p & 0377;
669 				if (a == A_END_LIST)
670 				{
671 					/*
672 					 * We get here only if the original
673 					 * cmd string passed in was empty ("").
674 					 * I don't think that can happen,
675 					 * but just in case ...
676 					 */
677 					return (A_UINVALID);
678 				}
679 				/*
680 				 * Check for an "extra" string.
681 				 */
682 				if (a & A_EXTRA)
683 				{
684 					*sp = ++p;
685 					while (*p != '\0')
686 						++p;
687 					a &= ~A_EXTRA;
688 				}
689 				if (a == A_X11MOUSE_IN)
690 					a = x11mouse_action(0);
691 				else if (a == A_X116MOUSE_IN)
692 					a = x116mouse_action(0);
693 				q = cmd-1;
694 			}
695 		} else if (*q == '\0')
696 		{
697 			/*
698 			 * Hit the end of the user's command,
699 			 * but not the end of the string in the command table.
700 			 * The user's command is incomplete.
701 			 */
702 			if (a == A_INVALID)
703 				a = A_PREFIX;
704 			q = cmd-1;
705 		} else
706 		{
707 			/*
708 			 * Not a match.
709 			 * Skip ahead to the next command in the
710 			 * command table, and reset the pointer
711 			 * to the beginning of the user's command.
712 			 */
713 			if (*p == '\0' && p[1] == A_END_LIST)
714 			{
715 				/*
716 				 * A_END_LIST is a special marker that tells
717 				 * us to abort the cmd search.
718 				 * Negative action means accept this action
719 				 * without searching any more cmd tables.
720 				 */
721 				return -a;
722 			}
723 			while (*p++ != '\0')
724 				continue;
725 			while (*p == A_SKIP)
726 				p++;
727 			if (*p & A_EXTRA)
728 				while (*++p != '\0')
729 					continue;
730 			q = cmd-1;
731 		}
732 	}
733 	return (a);
734 }
735 
736 /*
737  * Decode a command character and return the associated action.
738  * The "extra" string, if any, is returned in sp.
739  */
740 static int cmd_decode(struct tablelist *tlist, constant char *cmd, constant char **sp)
741 {
742 	struct tablelist *t;
743 	int action = A_INVALID;
744 
745 	/*
746 	 * Search for the cmd thru all the command tables.
747 	 * If we find it more than once, take the last one.
748 	 */
749 	*sp = NULL;
750 	for (t = tlist;  t != NULL;  t = t->t_next)
751 	{
752 		constant char *tsp;
753 		int taction = cmd_search(cmd, (char *) t->t_start, (char *) t->t_end, &tsp);
754 		if (taction == A_UINVALID)
755 			taction = A_INVALID;
756 		if (taction != A_INVALID)
757 		{
758 			*sp = tsp;
759 			if (taction < 0)
760 				return (-taction);
761 			action = taction;
762 		}
763 	}
764 	return (action);
765 }
766 
767 /*
768  * Decode a command from the cmdtables list.
769  */
770 public int fcmd_decode(constant char *cmd, constant char **sp)
771 {
772 	return (cmd_decode(list_fcmd_tables, cmd, sp));
773 }
774 
775 /*
776  * Decode a command from the edittables list.
777  */
778 public int ecmd_decode(constant char *cmd, constant char **sp)
779 {
780 	return (cmd_decode(list_ecmd_tables, cmd, sp));
781 }
782 
783 /*
784  * Get the value of an environment variable.
785  * Looks first in the lesskey file, then in the real environment.
786  */
787 public constant char * lgetenv(constant char *var)
788 {
789 	int a;
790 	constant char *s;
791 
792 	a = cmd_decode(list_var_tables, var, &s);
793 	if (a == EV_OK)
794 		return (s);
795 	s = getenv(var);
796 	if (s != NULL && *s != '\0')
797 		return (s);
798 	a = cmd_decode(list_sysvar_tables, var, &s);
799 	if (a == EV_OK)
800 		return (s);
801 	return (NULL);
802 }
803 
804 /*
805  * Like lgetenv, but also uses a buffer partially filled with an env table.
806  */
807 public constant char * lgetenv_ext(constant char *var, unsigned char *env_buf, size_t env_buf_len)
808 {
809 	constant char *r;
810 	size_t e;
811 	size_t env_end = 0;
812 
813 	for (e = 0;;)
814 	{
815 		for (; e < env_buf_len; e++)
816 			if (env_buf[e] == '\0')
817 				break;
818 		if (e >= env_buf_len) break;
819 		if (env_buf[++e] & A_EXTRA)
820 		{
821 			for (e = e+1; e < env_buf_len; e++)
822 				if (env_buf[e] == '\0')
823 					break;
824 		}
825 		e++;
826 		if (e >= env_buf_len) break;
827 		env_end = e;
828 	}
829 	/* Temporarily add env_buf to var_tables, do the lookup, then remove it. */
830 	add_uvar_table(env_buf, env_end);
831 	r = lgetenv(var);
832 	pop_cmd_table(&list_var_tables);
833 	return r;
834 }
835 
836 /*
837  * Is a string null or empty?
838  */
839 public lbool isnullenv(constant char *s)
840 {
841 	return (s == NULL || *s == '\0');
842 }
843 
844 #if USERFILE
845 /*
846  * Get an "integer" from a lesskey file.
847  * Integers are stored in a funny format:
848  * two bytes, low order first, in radix KRADIX.
849  */
850 static size_t gint(unsigned char **sp)
851 {
852 	size_t n;
853 
854 	n = *(*sp)++;
855 	n += *(*sp)++ * KRADIX;
856 	return (n);
857 }
858 
859 /*
860  * Process an old (pre-v241) lesskey file.
861  */
862 static int old_lesskey(unsigned char *buf, size_t len)
863 {
864 	/*
865 	 * Old-style lesskey file.
866 	 * The file must end with either
867 	 *     ...,cmd,0,action
868 	 * or  ...,cmd,0,action|A_EXTRA,string,0
869 	 * So the last byte or the second to last byte must be zero.
870 	 */
871 	if (buf[len-1] != '\0' && buf[len-2] != '\0')
872 		return (-1);
873 	add_fcmd_table(buf, len);
874 	return (0);
875 }
876 
877 /*
878  * Process a new (post-v241) lesskey file.
879  */
880 static int new_lesskey(unsigned char *buf, size_t len, lbool sysvar)
881 {
882 	unsigned char *p;
883 	unsigned char *end;
884 	int c;
885 	size_t n;
886 
887 	/*
888 	 * New-style lesskey file.
889 	 * Extract the pieces.
890 	 */
891 	if (buf[len-3] != C0_END_LESSKEY_MAGIC ||
892 	    buf[len-2] != C1_END_LESSKEY_MAGIC ||
893 	    buf[len-1] != C2_END_LESSKEY_MAGIC)
894 		return (-1);
895 	p = buf + 4;
896 	end = buf + len;
897 	for (;;)
898 	{
899 		c = *p++;
900 		switch (c)
901 		{
902 		case CMD_SECTION:
903 			n = gint(&p);
904 			if (p+n >= end)
905 				return (-1);
906 			add_fcmd_table(p, n);
907 			p += n;
908 			break;
909 		case EDIT_SECTION:
910 			n = gint(&p);
911 			if (p+n >= end)
912 				return (-1);
913 			add_ecmd_table(p, n);
914 			p += n;
915 			break;
916 		case VAR_SECTION:
917 			n = gint(&p);
918 			if (p+n >= end)
919 				return (-1);
920 			if (sysvar)
921 				add_sysvar_table(p, n);
922 			else
923 				add_uvar_table(p, n);
924 			p += n;
925 			break;
926 		case END_SECTION:
927 			return (0);
928 		default:
929 			/*
930 			 * Unrecognized section type.
931 			 */
932 			return (-1);
933 		}
934 	}
935 }
936 
937 /*
938  * Set up a user command table, based on a "lesskey" file.
939  */
940 public int lesskey(constant char *filename, lbool sysvar)
941 {
942 	unsigned char *buf;
943 	POSITION len;
944 	ssize_t n;
945 	int f;
946 
947 	if (!secure_allow(SF_LESSKEY))
948 		return (1);
949 	/*
950 	 * Try to open the lesskey file.
951 	 */
952 	f = open(filename, OPEN_READ);
953 	if (f < 0)
954 		return (1);
955 
956 	/*
957 	 * Read the file into a buffer.
958 	 * We first figure out the size of the file and allocate space for it.
959 	 * {{ Minimal error checking is done here.
960 	 *    A garbage .less file will produce strange results.
961 	 *    To avoid a large amount of error checking code here, we
962 	 *    rely on the lesskey program to generate a good .less file. }}
963 	 */
964 	len = filesize(f);
965 	if (len == NULL_POSITION || len < 3)
966 	{
967 		/*
968 		 * Bad file (valid file must have at least 3 chars).
969 		 */
970 		close(f);
971 		return (-1);
972 	}
973 	if ((buf = (unsigned char *) calloc((size_t)len, sizeof(char))) == NULL)
974 	{
975 		close(f);
976 		return (-1);
977 	}
978 	if (less_lseek(f, (less_off_t)0, SEEK_SET) == BAD_LSEEK)
979 	{
980 		free(buf);
981 		close(f);
982 		return (-1);
983 	}
984 	n = read(f, buf, (size_t) len);
985 	close(f);
986 	if (n != len)
987 	{
988 		free(buf);
989 		return (-1);
990 	}
991 
992 	/*
993 	 * Figure out if this is an old-style (before version 241)
994 	 * or new-style lesskey file format.
995 	 */
996 	if (len < 4 ||
997 	    buf[0] != C0_LESSKEY_MAGIC || buf[1] != C1_LESSKEY_MAGIC ||
998 	    buf[2] != C2_LESSKEY_MAGIC || buf[3] != C3_LESSKEY_MAGIC)
999 		return (old_lesskey(buf, (size_t) len));
1000 	return (new_lesskey(buf, (size_t) len, sysvar));
1001 }
1002 
1003 #if HAVE_LESSKEYSRC
1004 static int lesskey_text(constant char *filename, lbool sysvar, lbool content)
1005 {
1006 	static struct lesskey_tables tables;
1007 	if (!secure_allow(SF_LESSKEY))
1008 		return (1);
1009 	int r = content ? parse_lesskey_content(filename, &tables) : parse_lesskey(filename, &tables);
1010 	if (r != 0)
1011 		return (r);
1012 	add_fcmd_table(tables.cmdtable.buf.data, tables.cmdtable.buf.end);
1013 	add_ecmd_table(tables.edittable.buf.data, tables.edittable.buf.end);
1014 	if (sysvar)
1015 		add_sysvar_table(tables.vartable.buf.data, tables.vartable.buf.end);
1016 	else
1017 		add_uvar_table(tables.vartable.buf.data, tables.vartable.buf.end);
1018 	return (0);
1019 }
1020 
1021 public int lesskey_src(constant char *filename, lbool sysvar)
1022 {
1023 	return lesskey_text(filename, sysvar, FALSE);
1024 }
1025 
1026 public int lesskey_content(constant char *content, lbool sysvar)
1027 {
1028 	return lesskey_text(content, sysvar, TRUE);
1029 }
1030 
1031 void lesskey_parse_error(char *s)
1032 {
1033 	PARG parg;
1034 	parg.p_string = s;
1035 	error("%s", &parg);
1036 }
1037 #endif /* HAVE_LESSKEYSRC */
1038 
1039 /*
1040  * Add a lesskey file.
1041  */
1042 static int add_hometable(int (*call_lesskey)(constant char *, lbool), constant char *envname, constant char *def_filename, lbool sysvar)
1043 {
1044 	char *filename = NULL;
1045 	constant char *efilename;
1046 	int r;
1047 
1048 	if (envname != NULL && (efilename = lgetenv(envname)) != NULL)
1049 		filename = save(efilename);
1050 	else if (sysvar) /* def_filename is full path */
1051 		filename = save(def_filename);
1052 	else /* def_filename is just basename */
1053 	{
1054 		/* Remove first char (normally a dot) unless stored in $HOME. */
1055 		constant char *xdg = lgetenv("XDG_CONFIG_HOME");
1056 		if (!isnullenv(xdg))
1057 			filename = dirfile(xdg, &def_filename[1], 1);
1058 		if (filename == NULL)
1059 		{
1060 			constant char *home = lgetenv("HOME");
1061 			if (!isnullenv(home))
1062 			{
1063 				char *cfg_dir = dirfile(home, ".config", 0);
1064 				filename = dirfile(cfg_dir, &def_filename[1], 1);
1065 				free(cfg_dir);
1066 			}
1067 		}
1068 		if (filename == NULL)
1069 			filename = homefile(def_filename);
1070 	}
1071 	if (filename == NULL)
1072 		return -1;
1073 	r = (*call_lesskey)(filename, sysvar);
1074 	free(filename);
1075 	return (r);
1076 }
1077 
1078 /*
1079  * Add the content of a lesskey source file.
1080  */
1081 static void add_content_table(int (*call_lesskey)(constant char *, lbool), constant char *envname, lbool sysvar)
1082 {
1083 	(void) call_lesskey; /* not used */
1084 	constant char *content = lgetenv(envname);
1085 	if (isnullenv(content))
1086 		return;
1087 	lesskey_content(content, sysvar);
1088 }
1089 #endif /* USERFILE */
1090 
1091 /*
1092  * See if a char is a special line-editing command.
1093  */
1094 public int editchar(char c, int flags)
1095 {
1096 	int action;
1097 	int nch;
1098 	constant char *s;
1099 	char usercmd[MAX_CMDLEN+1];
1100 
1101 	/*
1102 	 * An editing character could actually be a sequence of characters;
1103 	 * for example, an escape sequence sent by pressing the uparrow key.
1104 	 * To match the editing string, we use the command decoder
1105 	 * but give it the edit-commands command table
1106 	 * This table is constructed to match the user's keyboard.
1107 	 */
1108 	if (c == erase_char || c == erase2_char)
1109 		return (EC_BACKSPACE);
1110 	if (c == kill_char)
1111 	{
1112 #if MSDOS_COMPILER==WIN32C
1113 		if (!win32_kbhit())
1114 #endif
1115 		return (EC_LINEKILL);
1116 	}
1117 
1118 	/*
1119 	 * Collect characters in a buffer.
1120 	 * Start with the one we have, and get more if we need them.
1121 	 */
1122 	nch = 0;
1123 	do {
1124 		if (nch > 0)
1125 			c = getcc();
1126 		usercmd[nch] = c;
1127 		usercmd[nch+1] = '\0';
1128 		nch++;
1129 		action = ecmd_decode(usercmd, &s);
1130 	} while (action == A_PREFIX && nch < MAX_CMDLEN);
1131 
1132 	if (action == EC_X11MOUSE)
1133 		return (x11mouse_action(1));
1134 	if (action == EC_X116MOUSE)
1135 		return (x116mouse_action(1));
1136 
1137 	if (flags & ECF_NORIGHTLEFT)
1138 	{
1139 		switch (action)
1140 		{
1141 		case EC_RIGHT:
1142 		case EC_LEFT:
1143 			action = A_INVALID;
1144 			break;
1145 		}
1146 	}
1147 #if CMD_HISTORY
1148 	if (flags & ECF_NOHISTORY)
1149 	{
1150 		/*
1151 		 * The caller says there is no history list.
1152 		 * Reject any history-manipulation action.
1153 		 */
1154 		switch (action)
1155 		{
1156 		case EC_UP:
1157 		case EC_DOWN:
1158 			action = A_INVALID;
1159 			break;
1160 		}
1161 	}
1162 #endif
1163 #if TAB_COMPLETE_FILENAME
1164 	if (flags & ECF_NOCOMPLETE)
1165 	{
1166 		/*
1167 		 * The caller says we don't want any filename completion cmds.
1168 		 * Reject them.
1169 		 */
1170 		switch (action)
1171 		{
1172 		case EC_F_COMPLETE:
1173 		case EC_B_COMPLETE:
1174 		case EC_EXPAND:
1175 			action = A_INVALID;
1176 			break;
1177 		}
1178 	}
1179 #endif
1180 	if ((flags & ECF_PEEK) || action == A_INVALID)
1181 	{
1182 		/*
1183 		 * We're just peeking, or we didn't understand the command.
1184 		 * Unget all the characters we read in the loop above.
1185 		 * This does NOT include the original character that was
1186 		 * passed in as a parameter.
1187 		 */
1188 		while (nch > 1)
1189 		{
1190 			ungetcc(usercmd[--nch]);
1191 		}
1192 	} else
1193 	{
1194 		if (s != NULL)
1195 			ungetsc(s);
1196 	}
1197 	return action;
1198 }
1199 
1200