1/*
2 * Copyright (C) 1984-2015  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
36extern int erase_char, erase2_char, kill_char;
37extern int secure;
38
39#define SK(k) \
40	SK_SPECIAL_KEY, (k), 6, 1, 1, 1
41/*
42 * Command table is ordered roughly according to expected
43 * frequency of use, so the common commands are near the beginning.
44 */
45
46static unsigned char cmdtable[] =
47{
48	'\r',0,				A_F_LINE,
49	'\n',0,				A_F_LINE,
50	'e',0,				A_F_LINE,
51	'j',0,				A_F_LINE,
52	SK(SK_DOWN_ARROW),0,		A_F_LINE,
53	CONTROL('E'),0,			A_F_LINE,
54	CONTROL('N'),0,			A_F_LINE,
55	'k',0,				A_B_LINE,
56	'y',0,				A_B_LINE,
57	CONTROL('Y'),0,			A_B_LINE,
58	SK(SK_CONTROL_K),0,		A_B_LINE,
59	CONTROL('P'),0,			A_B_LINE,
60	SK(SK_UP_ARROW),0,		A_B_LINE,
61	'J',0,				A_FF_LINE,
62	'K',0,				A_BF_LINE,
63	'Y',0,				A_BF_LINE,
64	'd',0,				A_F_SCROLL,
65	CONTROL('D'),0,			A_F_SCROLL,
66	'u',0,				A_B_SCROLL,
67	CONTROL('U'),0,			A_B_SCROLL,
68	' ',0,				A_F_SCREEN,
69	'f',0,				A_F_SCREEN,
70	CONTROL('F'),0,			A_F_SCREEN,
71	CONTROL('V'),0,			A_F_SCREEN,
72	SK(SK_PAGE_DOWN),0,		A_F_SCREEN,
73	'b',0,				A_B_SCREEN,
74	CONTROL('B'),0,			A_B_SCREEN,
75	ESC,'v',0,			A_B_SCREEN,
76	SK(SK_PAGE_UP),0,		A_B_SCREEN,
77	'z',0,				A_F_WINDOW,
78	'w',0,				A_B_WINDOW,
79	ESC,' ',0,			A_FF_SCREEN,
80	'F',0,				A_F_FOREVER,
81	ESC,'F',0,			A_F_UNTIL_HILITE,
82	'R',0,				A_FREPAINT,
83	'r',0,				A_REPAINT,
84	CONTROL('R'),0,			A_REPAINT,
85	CONTROL('L'),0,			A_REPAINT,
86	ESC,'u',0,			A_UNDO_SEARCH,
87	'g',0,				A_GOLINE,
88	SK(SK_HOME),0,			A_GOLINE,
89	'<',0,				A_GOLINE,
90	ESC,'<',0,			A_GOLINE,
91	'p',0,				A_PERCENT,
92	'%',0,				A_PERCENT,
93	ESC,'[',0,			A_LSHIFT,
94	ESC,']',0,			A_RSHIFT,
95	ESC,'(',0,			A_LSHIFT,
96	ESC,')',0,			A_RSHIFT,
97	SK(SK_RIGHT_ARROW),0,		A_RSHIFT,
98	SK(SK_LEFT_ARROW),0,		A_LSHIFT,
99	'{',0,				A_F_BRACKET|A_EXTRA,	'{','}',0,
100	'}',0,				A_B_BRACKET|A_EXTRA,	'{','}',0,
101	'(',0,				A_F_BRACKET|A_EXTRA,	'(',')',0,
102	')',0,				A_B_BRACKET|A_EXTRA,	'(',')',0,
103	'[',0,				A_F_BRACKET|A_EXTRA,	'[',']',0,
104	']',0,				A_B_BRACKET|A_EXTRA,	'[',']',0,
105	ESC,CONTROL('F'),0,		A_F_BRACKET,
106	ESC,CONTROL('B'),0,		A_B_BRACKET,
107	'G',0,				A_GOEND,
108	ESC,'G',0,			A_GOEND_BUF,
109	ESC,'>',0,			A_GOEND,
110	'>',0,				A_GOEND,
111	SK(SK_END),0,			A_GOEND,
112	'P',0,				A_GOPOS,
113
114	'0',0,				A_DIGIT,
115	'1',0,				A_DIGIT,
116	'2',0,				A_DIGIT,
117	'3',0,				A_DIGIT,
118	'4',0,				A_DIGIT,
119	'5',0,				A_DIGIT,
120	'6',0,				A_DIGIT,
121	'7',0,				A_DIGIT,
122	'8',0,				A_DIGIT,
123	'9',0,				A_DIGIT,
124	'.',0,				A_DIGIT,
125
126	'=',0,				A_STAT,
127	CONTROL('G'),0,			A_STAT,
128	':','f',0,			A_STAT,
129	'/',0,				A_F_SEARCH,
130	'?',0,				A_B_SEARCH,
131	ESC,'/',0,			A_F_SEARCH|A_EXTRA,	'*',0,
132	ESC,'?',0,			A_B_SEARCH|A_EXTRA,	'*',0,
133	'n',0,				A_AGAIN_SEARCH,
134	ESC,'n',0,			A_T_AGAIN_SEARCH,
135	'N',0,				A_REVERSE_SEARCH,
136	ESC,'N',0,			A_T_REVERSE_SEARCH,
137	'&',0,				A_FILTER,
138	'm',0,				A_SETMARK,
139	'\'',0,				A_GOMARK,
140	CONTROL('X'),CONTROL('X'),0,	A_GOMARK,
141	'E',0,				A_EXAMINE,
142	':','e',0,			A_EXAMINE,
143	CONTROL('X'),CONTROL('V'),0,	A_EXAMINE,
144	':','n',0,			A_NEXT_FILE,
145	':','p',0,			A_PREV_FILE,
146	't',0,				A_NEXT_TAG,
147	'T',0,				A_PREV_TAG,
148	':','x',0,			A_INDEX_FILE,
149	':','d',0,			A_REMOVE_FILE,
150	'-',0,				A_OPT_TOGGLE,
151	':','t',0,			A_OPT_TOGGLE|A_EXTRA,	't',0,
152	's',0,				A_OPT_TOGGLE|A_EXTRA,	'o',0,
153	'_',0,				A_DISP_OPTION,
154	'|',0,				A_PIPE,
155	'v',0,				A_VISUAL,
156	'!',0,				A_SHELL,
157	'+',0,				A_FIRSTCMD,
158
159	'H',0,				A_HELP,
160	'h',0,				A_HELP,
161	SK(SK_F1),0,			A_HELP,
162	'V',0,				A_VERSION,
163	'q',0,				A_QUIT,
164	'Q',0,				A_QUIT,
165	':','q',0,			A_QUIT,
166	':','Q',0,			A_QUIT,
167	'Z','Z',0,			A_QUIT
168};
169
170static unsigned char edittable[] =
171{
172	'\t',0,	    			EC_F_COMPLETE,	/* TAB */
173	'\17',0,			EC_B_COMPLETE,	/* BACKTAB */
174	SK(SK_BACKTAB),0,		EC_B_COMPLETE,	/* BACKTAB */
175	ESC,'\t',0,			EC_B_COMPLETE,	/* ESC TAB */
176	CONTROL('L'),0,			EC_EXPAND,	/* CTRL-L */
177	CONTROL('V'),0,			EC_LITERAL,	/* BACKSLASH */
178	CONTROL('A'),0,			EC_LITERAL,	/* BACKSLASH */
179   	ESC,'l',0,			EC_RIGHT,	/* ESC l */
180	SK(SK_RIGHT_ARROW),0,		EC_RIGHT,	/* RIGHTARROW */
181	ESC,'h',0,			EC_LEFT,	/* ESC h */
182	SK(SK_LEFT_ARROW),0,		EC_LEFT,	/* LEFTARROW */
183	ESC,'b',0,			EC_W_LEFT,	/* ESC b */
184	ESC,SK(SK_LEFT_ARROW),0,	EC_W_LEFT,	/* ESC LEFTARROW */
185	SK(SK_CTL_LEFT_ARROW),0,	EC_W_LEFT,	/* CTRL-LEFTARROW */
186	ESC,'w',0,			EC_W_RIGHT,	/* ESC w */
187	ESC,SK(SK_RIGHT_ARROW),0,	EC_W_RIGHT,	/* ESC RIGHTARROW */
188	SK(SK_CTL_RIGHT_ARROW),0,	EC_W_RIGHT,	/* CTRL-RIGHTARROW */
189	ESC,'i',0,			EC_INSERT,	/* ESC i */
190	SK(SK_INSERT),0,		EC_INSERT,	/* INSERT */
191	ESC,'x',0,			EC_DELETE,	/* ESC x */
192	SK(SK_DELETE),0,		EC_DELETE,	/* DELETE */
193	ESC,'X',0,			EC_W_DELETE,	/* ESC X */
194	ESC,SK(SK_DELETE),0,		EC_W_DELETE,	/* ESC DELETE */
195	SK(SK_CTL_DELETE),0,		EC_W_DELETE,	/* CTRL-DELETE */
196	SK(SK_CTL_BACKSPACE),0,		EC_W_BACKSPACE, /* CTRL-BACKSPACE */
197	ESC,'\b',0,			EC_W_BACKSPACE,	/* ESC BACKSPACE */
198	ESC,'0',0,			EC_HOME,	/* ESC 0 */
199	SK(SK_HOME),0,			EC_HOME,	/* HOME */
200	ESC,'$',0,			EC_END,		/* ESC $ */
201	SK(SK_END),0,			EC_END,		/* END */
202	ESC,'k',0,			EC_UP,		/* ESC k */
203	SK(SK_UP_ARROW),0,		EC_UP,		/* UPARROW */
204	ESC,'j',0,			EC_DOWN,	/* ESC j */
205	SK(SK_DOWN_ARROW),0,		EC_DOWN,	/* DOWNARROW */
206	CONTROL('G'),0,			EC_ABORT,	/* CTRL-G */
207};
208
209/*
210 * Structure to support a list of command tables.
211 */
212struct tablelist
213{
214	struct tablelist *t_next;
215	char *t_start;
216	char *t_end;
217};
218
219/*
220 * List of command tables and list of line-edit tables.
221 */
222static struct tablelist *list_fcmd_tables = NULL;
223static struct tablelist *list_ecmd_tables = NULL;
224static struct tablelist *list_var_tables = NULL;
225static struct tablelist *list_sysvar_tables = NULL;
226
227
228/*
229 * Expand special key abbreviations in a command table.
230 */
231	static void
232expand_special_keys(table, len)
233	char *table;
234	int len;
235{
236	register char *fm;
237	register char *to;
238	register int a;
239	char *repl;
240	int klen;
241
242	for (fm = table;  fm < table + len; )
243	{
244		/*
245		 * Rewrite each command in the table with any
246		 * special key abbreviations expanded.
247		 */
248		for (to = fm;  *fm != '\0'; )
249		{
250			if (*fm != SK_SPECIAL_KEY)
251			{
252				*to++ = *fm++;
253				continue;
254			}
255			/*
256			 * After SK_SPECIAL_KEY, next byte is the type
257			 * of special key (one of the SK_* contants),
258			 * and the byte after that is the number of bytes,
259			 * N, reserved by the abbreviation (including the
260			 * SK_SPECIAL_KEY and key type bytes).
261			 * Replace all N bytes with the actual bytes
262			 * output by the special key on this terminal.
263			 */
264			repl = special_key_str(fm[1]);
265			klen = fm[2] & 0377;
266			fm += klen;
267			if (repl == NULL || (int) strlen(repl) > klen)
268				repl = "\377";
269			while (*repl != '\0')
270				*to++ = *repl++;
271		}
272		*to++ = '\0';
273		/*
274		 * Fill any unused bytes between end of command and
275		 * the action byte with A_SKIP.
276		 */
277		while (to <= fm)
278			*to++ = A_SKIP;
279		fm++;
280		a = *fm++ & 0377;
281		if (a & A_EXTRA)
282		{
283			while (*fm++ != '\0')
284				continue;
285		}
286	}
287}
288
289/*
290 * Initialize the command lists.
291 */
292	public void
293init_cmds()
294{
295	/*
296	 * Add the default command tables.
297	 */
298	add_fcmd_table((char*)cmdtable, sizeof(cmdtable));
299	add_ecmd_table((char*)edittable, sizeof(edittable));
300#if USERFILE
301	/*
302	 * For backwards compatibility,
303	 * try to add tables in the OLD system lesskey file.
304	 */
305#ifdef BINDIR
306	add_hometable(NULL, BINDIR "/.sysless", 1);
307#endif
308	/*
309	 * Try to add the tables in the system lesskey file.
310	 */
311	add_hometable("LESSKEY_SYSTEM", LESSKEYFILE_SYS, 1);
312	/*
313	 * Try to add the tables in the standard lesskey file "$HOME/.less".
314	 */
315	add_hometable("LESSKEY", LESSKEYFILE, 0);
316#endif
317}
318
319/*
320 * Add a command table.
321 */
322	static int
323add_cmd_table(tlist, buf, len)
324	struct tablelist **tlist;
325	char *buf;
326	int len;
327{
328	register struct tablelist *t;
329
330	if (len == 0)
331		return (0);
332	/*
333	 * Allocate a tablelist structure, initialize it,
334	 * and link it into the list of tables.
335	 */
336	if ((t = (struct tablelist *)
337			calloc(1, sizeof(struct tablelist))) == NULL)
338	{
339		return (-1);
340	}
341	expand_special_keys(buf, len);
342	t->t_start = buf;
343	t->t_end = buf + len;
344	t->t_next = *tlist;
345	*tlist = t;
346	return (0);
347}
348
349/*
350 * Add a command table.
351 */
352	public void
353add_fcmd_table(buf, len)
354	char *buf;
355	int len;
356{
357	if (add_cmd_table(&list_fcmd_tables, buf, len) < 0)
358		error("Warning: some commands disabled", NULL_PARG);
359}
360
361/*
362 * Add an editing command table.
363 */
364	public void
365add_ecmd_table(buf, len)
366	char *buf;
367	int len;
368{
369	if (add_cmd_table(&list_ecmd_tables, buf, len) < 0)
370		error("Warning: some edit commands disabled", NULL_PARG);
371}
372
373/*
374 * Add an environment variable table.
375 */
376	static void
377add_var_table(tlist, buf, len)
378	struct tablelist **tlist;
379	char *buf;
380	int len;
381{
382	if (add_cmd_table(tlist, buf, len) < 0)
383		error("Warning: environment variables from lesskey file unavailable", NULL_PARG);
384}
385
386/*
387 * Search a single command table for the command string in cmd.
388 */
389	static int
390cmd_search(cmd, table, endtable, sp)
391	char *cmd;
392	char *table;
393	char *endtable;
394	char **sp;
395{
396	register char *p;
397	register char *q;
398	register int a;
399
400	*sp = NULL;
401	for (p = table, q = cmd;  p < endtable;  p++, q++)
402	{
403		if (*p == *q)
404		{
405			/*
406			 * Current characters match.
407			 * If we're at the end of the string, we've found it.
408			 * Return the action code, which is the character
409			 * after the null at the end of the string
410			 * in the command table.
411			 */
412			if (*p == '\0')
413			{
414				a = *++p & 0377;
415				while (a == A_SKIP)
416					a = *++p & 0377;
417				if (a == A_END_LIST)
418				{
419					/*
420					 * We get here only if the original
421					 * cmd string passed in was empty ("").
422					 * I don't think that can happen,
423					 * but just in case ...
424					 */
425					return (A_UINVALID);
426				}
427				/*
428				 * Check for an "extra" string.
429				 */
430				if (a & A_EXTRA)
431				{
432					*sp = ++p;
433					a &= ~A_EXTRA;
434				}
435				return (a);
436			}
437		} else if (*q == '\0')
438		{
439			/*
440			 * Hit the end of the user's command,
441			 * but not the end of the string in the command table.
442			 * The user's command is incomplete.
443			 */
444			return (A_PREFIX);
445		} else
446		{
447			/*
448			 * Not a match.
449			 * Skip ahead to the next command in the
450			 * command table, and reset the pointer
451			 * to the beginning of the user's command.
452			 */
453			if (*p == '\0' && p[1] == A_END_LIST)
454			{
455				/*
456				 * A_END_LIST is a special marker that tells
457				 * us to abort the cmd search.
458				 */
459				return (A_UINVALID);
460			}
461			while (*p++ != '\0')
462				continue;
463			while (*p == A_SKIP)
464				p++;
465			if (*p & A_EXTRA)
466				while (*++p != '\0')
467					continue;
468			q = cmd-1;
469		}
470	}
471	/*
472	 * No match found in the entire command table.
473	 */
474	return (A_INVALID);
475}
476
477/*
478 * Decode a command character and return the associated action.
479 * The "extra" string, if any, is returned in sp.
480 */
481	static int
482cmd_decode(tlist, cmd, sp)
483	struct tablelist *tlist;
484	char *cmd;
485	char **sp;
486{
487	register struct tablelist *t;
488	register int action = A_INVALID;
489
490	/*
491	 * Search thru all the command tables.
492	 * Stop when we find an action which is not A_INVALID.
493	 */
494	for (t = tlist;  t != NULL;  t = t->t_next)
495	{
496		action = cmd_search(cmd, t->t_start, t->t_end, sp);
497		if (action != A_INVALID)
498			break;
499	}
500	if (action == A_UINVALID)
501		action = A_INVALID;
502	return (action);
503}
504
505/*
506 * Decode a command from the cmdtables list.
507 */
508	public int
509fcmd_decode(cmd, sp)
510	char *cmd;
511	char **sp;
512{
513	return (cmd_decode(list_fcmd_tables, cmd, sp));
514}
515
516/*
517 * Decode a command from the edittables list.
518 */
519	public int
520ecmd_decode(cmd, sp)
521	char *cmd;
522	char **sp;
523{
524	return (cmd_decode(list_ecmd_tables, cmd, sp));
525}
526
527/*
528 * Get the value of an environment variable.
529 * Looks first in the lesskey file, then in the real environment.
530 */
531	public char *
532lgetenv(var)
533	char *var;
534{
535	int a;
536	char *s;
537
538	a = cmd_decode(list_var_tables, var, &s);
539	if (a == EV_OK)
540		return (s);
541	s = getenv(var);
542	if (s != NULL && *s != '\0')
543		return (s);
544	a = cmd_decode(list_sysvar_tables, var, &s);
545	if (a == EV_OK)
546		return (s);
547	return (NULL);
548}
549
550#if USERFILE
551/*
552 * Get an "integer" from a lesskey file.
553 * Integers are stored in a funny format:
554 * two bytes, low order first, in radix KRADIX.
555 */
556	static int
557gint(sp)
558	char **sp;
559{
560	int n;
561
562	n = *(*sp)++;
563	n += *(*sp)++ * KRADIX;
564	return (n);
565}
566
567/*
568 * Process an old (pre-v241) lesskey file.
569 */
570	static int
571old_lesskey(buf, len)
572	char *buf;
573	int len;
574{
575	/*
576	 * Old-style lesskey file.
577	 * The file must end with either
578	 *     ...,cmd,0,action
579	 * or  ...,cmd,0,action|A_EXTRA,string,0
580	 * So the last byte or the second to last byte must be zero.
581	 */
582	if (buf[len-1] != '\0' && buf[len-2] != '\0')
583		return (-1);
584	add_fcmd_table(buf, len);
585	return (0);
586}
587
588/*
589 * Process a new (post-v241) lesskey file.
590 */
591	static int
592new_lesskey(buf, len, sysvar)
593	char *buf;
594	int len;
595	int sysvar;
596{
597	char *p;
598	register int c;
599	register int n;
600
601	/*
602	 * New-style lesskey file.
603	 * Extract the pieces.
604	 */
605	if (buf[len-3] != C0_END_LESSKEY_MAGIC ||
606	    buf[len-2] != C1_END_LESSKEY_MAGIC ||
607	    buf[len-1] != C2_END_LESSKEY_MAGIC)
608		return (-1);
609	p = buf + 4;
610	for (;;)
611	{
612		c = *p++;
613		switch (c)
614		{
615		case CMD_SECTION:
616			n = gint(&p);
617			add_fcmd_table(p, n);
618			p += n;
619			break;
620		case EDIT_SECTION:
621			n = gint(&p);
622			add_ecmd_table(p, n);
623			p += n;
624			break;
625		case VAR_SECTION:
626			n = gint(&p);
627			add_var_table((sysvar) ?
628				&list_sysvar_tables : &list_var_tables, p, n);
629			p += n;
630			break;
631		case END_SECTION:
632			return (0);
633		default:
634			/*
635			 * Unrecognized section type.
636			 */
637			return (-1);
638		}
639	}
640}
641
642/*
643 * Set up a user command table, based on a "lesskey" file.
644 */
645	public int
646lesskey(filename, sysvar)
647	char *filename;
648	int sysvar;
649{
650	register char *buf;
651	register POSITION len;
652	register long n;
653	register int f;
654
655	if (secure)
656		return (1);
657	/*
658	 * Try to open the lesskey file.
659	 */
660	filename = shell_unquote(filename);
661	f = open(filename, OPEN_READ);
662	free(filename);
663	if (f < 0)
664		return (1);
665
666	/*
667	 * Read the file into a buffer.
668	 * We first figure out the size of the file and allocate space for it.
669	 * {{ Minimal error checking is done here.
670	 *    A garbage .less file will produce strange results.
671	 *    To avoid a large amount of error checking code here, we
672	 *    rely on the lesskey program to generate a good .less file. }}
673	 */
674	len = filesize(f);
675	if (len == NULL_POSITION || len < 3)
676	{
677		/*
678		 * Bad file (valid file must have at least 3 chars).
679		 */
680		close(f);
681		return (-1);
682	}
683	if ((buf = (char *) calloc((int)len, sizeof(char))) == NULL)
684	{
685		close(f);
686		return (-1);
687	}
688	if (lseek(f, (off_t)0, SEEK_SET) == BAD_LSEEK)
689	{
690		free(buf);
691		close(f);
692		return (-1);
693	}
694	n = read(f, buf, (unsigned int) len);
695	close(f);
696	if (n != len)
697	{
698		free(buf);
699		return (-1);
700	}
701
702	/*
703	 * Figure out if this is an old-style (before version 241)
704	 * or new-style lesskey file format.
705	 */
706	if (buf[0] != C0_LESSKEY_MAGIC || buf[1] != C1_LESSKEY_MAGIC ||
707	    buf[2] != C2_LESSKEY_MAGIC || buf[3] != C3_LESSKEY_MAGIC)
708		return (old_lesskey(buf, (int)len));
709	return (new_lesskey(buf, (int)len, sysvar));
710}
711
712/*
713 * Add the standard lesskey file "$HOME/.less"
714 */
715	public void
716add_hometable(envname, def_filename, sysvar)
717	char *envname;
718	char *def_filename;
719	int sysvar;
720{
721	char *filename;
722	PARG parg;
723
724	if (envname != NULL && (filename = lgetenv(envname)) != NULL)
725		filename = save(filename);
726	else if (sysvar)
727		filename = save(def_filename);
728	else
729		filename = homefile(def_filename);
730	if (filename == NULL)
731		return;
732	if (lesskey(filename, sysvar) < 0)
733	{
734		parg.p_string = filename;
735		error("Cannot use lesskey file \"%s\"", &parg);
736	}
737	free(filename);
738}
739#endif
740
741/*
742 * See if a char is a special line-editing command.
743 */
744	public int
745editchar(c, flags)
746	int c;
747	int flags;
748{
749	int action;
750	int nch;
751	char *s;
752	char usercmd[MAX_CMDLEN+1];
753
754	/*
755	 * An editing character could actually be a sequence of characters;
756	 * for example, an escape sequence sent by pressing the uparrow key.
757	 * To match the editing string, we use the command decoder
758	 * but give it the edit-commands command table
759	 * This table is constructed to match the user's keyboard.
760	 */
761	if (c == erase_char || c == erase2_char)
762		return (EC_BACKSPACE);
763	if (c == kill_char)
764		return (EC_LINEKILL);
765
766	/*
767	 * Collect characters in a buffer.
768	 * Start with the one we have, and get more if we need them.
769	 */
770	nch = 0;
771	do {
772	  	if (nch > 0)
773			c = getcc();
774		usercmd[nch] = c;
775		usercmd[nch+1] = '\0';
776		nch++;
777		action = ecmd_decode(usercmd, &s);
778	} while (action == A_PREFIX);
779
780	if (flags & EC_NORIGHTLEFT)
781	{
782		switch (action)
783		{
784		case EC_RIGHT:
785		case EC_LEFT:
786			action = A_INVALID;
787			break;
788		}
789	}
790#if CMD_HISTORY
791	if (flags & EC_NOHISTORY)
792	{
793		/*
794		 * The caller says there is no history list.
795		 * Reject any history-manipulation action.
796		 */
797		switch (action)
798		{
799		case EC_UP:
800		case EC_DOWN:
801			action = A_INVALID;
802			break;
803		}
804	}
805#endif
806#if TAB_COMPLETE_FILENAME
807	if (flags & EC_NOCOMPLETE)
808	{
809		/*
810		 * The caller says we don't want any filename completion cmds.
811		 * Reject them.
812		 */
813		switch (action)
814		{
815		case EC_F_COMPLETE:
816		case EC_B_COMPLETE:
817		case EC_EXPAND:
818			action = A_INVALID;
819			break;
820		}
821	}
822#endif
823	if ((flags & EC_PEEK) || action == A_INVALID)
824	{
825		/*
826		 * We're just peeking, or we didn't understand the command.
827		 * Unget all the characters we read in the loop above.
828		 * This does NOT include the original character that was
829		 * passed in as a parameter.
830		 */
831		while (nch > 1)
832		{
833			ungetcc(usercmd[--nch]);
834		}
835	} else
836	{
837		if (s != NULL)
838			ungetsc(s);
839	}
840	return action;
841}
842
843