xref: /openbsd/bin/ksh/syn.c (revision 4685f242)
1 /*	$OpenBSD: syn.c,v 1.40 2021/07/05 13:41:46 millert Exp $	*/
2 
3 /*
4  * shell parser (C version)
5  */
6 
7 #include <string.h>
8 
9 #include "sh.h"
10 #include "c_test.h"
11 
12 struct nesting_state {
13 	int	start_token;	/* token than began nesting (eg, FOR) */
14 	int	start_line;	/* line nesting began on */
15 };
16 
17 static void	yyparse(void);
18 static struct op *pipeline(int);
19 static struct op *andor(void);
20 static struct op *c_list(int);
21 static struct ioword *synio(int);
22 static void	musthave(int, int);
23 static struct op *nested(int, int, int);
24 static struct op *get_command(int);
25 static struct op *dogroup(void);
26 static struct op *thenpart(void);
27 static struct op *elsepart(void);
28 static struct op *caselist(void);
29 static struct op *casepart(int);
30 static struct op *function_body(char *, int);
31 static char **	wordlist(void);
32 static struct op *block(int, struct op *, struct op *, char **);
33 static struct op *newtp(int);
34 static void	syntaxerr(const char *) __attribute__((__noreturn__));
35 static void	nesting_push(struct nesting_state *, int);
36 static void	nesting_pop(struct nesting_state *);
37 static int	assign_command(char *);
38 static int	inalias(struct source *);
39 static int	dbtestp_isa(Test_env *, Test_meta);
40 static const char *dbtestp_getopnd(Test_env *, Test_op, int);
41 static int	dbtestp_eval(Test_env *, Test_op, const char *, const char *,
42 		    int);
43 static void	dbtestp_error(Test_env *, int, const char *);
44 
45 static	struct	op	*outtree; /* yyparse output */
46 
47 static struct nesting_state nesting;	/* \n changed to ; */
48 
49 static	int	reject;		/* token(cf) gets symbol again */
50 static	int	symbol;		/* yylex value */
51 
52 #define	token(cf) \
53 	((reject) ? (reject = false, symbol) : (symbol = yylex(cf)))
54 #define	tpeek(cf) \
55 	((reject) ? (symbol) : (reject = true, symbol = yylex(cf)))
56 
57 static void
yyparse(void)58 yyparse(void)
59 {
60 	int c;
61 
62 	reject = false;
63 
64 	outtree = c_list(source->type == SSTRING);
65 	c = tpeek(0);
66 	if (c == 0 && !outtree)
67 		outtree = newtp(TEOF);
68 	else if (c != '\n' && c != 0)
69 		syntaxerr(NULL);
70 }
71 
72 static struct op *
pipeline(int cf)73 pipeline(int cf)
74 {
75 	struct op *t, *p, *tl = NULL;
76 
77 	t = get_command(cf);
78 	if (t != NULL) {
79 		while (token(0) == '|') {
80 			if ((p = get_command(CONTIN)) == NULL)
81 				syntaxerr(NULL);
82 			if (tl == NULL)
83 				t = tl = block(TPIPE, t, p, NULL);
84 			else
85 				tl = tl->right = block(TPIPE, tl->right, p, NULL);
86 		}
87 		reject = true;
88 	}
89 	return (t);
90 }
91 
92 static struct op *
andor(void)93 andor(void)
94 {
95 	struct op *t, *p;
96 	int c;
97 
98 	t = pipeline(0);
99 	if (t != NULL) {
100 		while ((c = token(0)) == LOGAND || c == LOGOR) {
101 			if ((p = pipeline(CONTIN)) == NULL)
102 				syntaxerr(NULL);
103 			t = block(c == LOGAND? TAND: TOR, t, p, NULL);
104 		}
105 		reject = true;
106 	}
107 	return (t);
108 }
109 
110 static struct op *
c_list(int multi)111 c_list(int multi)
112 {
113 	struct op *t = NULL, *p, *tl = NULL;
114 	int c;
115 	int have_sep;
116 
117 	while (1) {
118 		p = andor();
119 		/* Token has always been read/rejected at this point, so
120 		 * we don't worry about what flags to pass token()
121 		 */
122 		c = token(0);
123 		have_sep = 1;
124 		if (c == '\n' && (multi || inalias(source))) {
125 			if (!p) /* ignore blank lines */
126 				continue;
127 		} else if (!p)
128 			break;
129 		else if (c == '&' || c == COPROC)
130 			p = block(c == '&' ? TASYNC : TCOPROC,
131 				  p, NULL, NULL);
132 		else if (c != ';')
133 			have_sep = 0;
134 		if (!t)
135 			t = p;
136 		else if (!tl)
137 			t = tl = block(TLIST, t, p, NULL);
138 		else
139 			tl = tl->right = block(TLIST, tl->right, p, NULL);
140 		if (!have_sep)
141 			break;
142 	}
143 	reject = true;
144 	return t;
145 }
146 
147 static struct ioword *
synio(int cf)148 synio(int cf)
149 {
150 	struct ioword *iop;
151 	int ishere;
152 
153 	if (tpeek(cf) != REDIR)
154 		return NULL;
155 	reject = false;
156 	iop = yylval.iop;
157 	ishere = (iop->flag&IOTYPE) == IOHERE;
158 	musthave(LWORD, ishere ? HEREDELIM : 0);
159 	if (ishere) {
160 		iop->delim = yylval.cp;
161 		if (*ident != 0) /* unquoted */
162 			iop->flag |= IOEVAL;
163 		if (herep >= &heres[HERES])
164 			yyerror("too many <<'s\n");
165 		*herep++ = iop;
166 	} else
167 		iop->name = yylval.cp;
168 	return iop;
169 }
170 
171 static void
musthave(int c,int cf)172 musthave(int c, int cf)
173 {
174 	if ((token(cf)) != c)
175 		syntaxerr(NULL);
176 }
177 
178 static struct op *
nested(int type,int smark,int emark)179 nested(int type, int smark, int emark)
180 {
181 	struct op *t;
182 	struct nesting_state old_nesting;
183 
184 	nesting_push(&old_nesting, smark);
185 	t = c_list(true);
186 	musthave(emark, KEYWORD|ALIAS);
187 	nesting_pop(&old_nesting);
188 	return (block(type, t, NULL, NULL));
189 }
190 
191 static struct op *
get_command(int cf)192 get_command(int cf)
193 {
194 	struct op *t;
195 	int c, iopn = 0, syniocf;
196 	struct ioword *iop, **iops;
197 	XPtrV args, vars;
198 	struct nesting_state old_nesting;
199 
200 	iops = areallocarray(NULL, NUFILE + 1,
201 	    sizeof(struct ioword *), ATEMP);
202 	XPinit(args, 16);
203 	XPinit(vars, 16);
204 
205 	syniocf = KEYWORD|ALIAS;
206 	switch (c = token(cf|KEYWORD|ALIAS|VARASN)) {
207 	default:
208 		reject = true;
209 		afree(iops, ATEMP);
210 		XPfree(args);
211 		XPfree(vars);
212 		return NULL; /* empty line */
213 
214 	case LWORD:
215 	case REDIR:
216 		reject = true;
217 		syniocf &= ~(KEYWORD|ALIAS);
218 		t = newtp(TCOM);
219 		t->lineno = source->line;
220 		while (1) {
221 			cf = (t->u.evalflags ? ARRAYVAR : 0) |
222 			    (XPsize(args) == 0 ? ALIAS|VARASN : CMDWORD);
223 			switch (tpeek(cf)) {
224 			case REDIR:
225 				if (iopn >= NUFILE)
226 					yyerror("too many redirections\n");
227 				iops[iopn++] = synio(cf);
228 				break;
229 
230 			case LWORD:
231 				reject = false;
232 				/* the iopn == 0 and XPsize(vars) == 0 are
233 				 * dubious but at&t ksh acts this way
234 				 */
235 				if (iopn == 0 && XPsize(vars) == 0 &&
236 				    XPsize(args) == 0 &&
237 				    assign_command(ident))
238 					t->u.evalflags = DOVACHECK;
239 				if ((XPsize(args) == 0 || Flag(FKEYWORD)) &&
240 				    is_wdvarassign(yylval.cp))
241 					XPput(vars, yylval.cp);
242 				else
243 					XPput(args, yylval.cp);
244 				break;
245 
246 			case '(':
247 				/* Check for "> foo (echo hi)", which at&t ksh
248 				 * allows (not POSIX, but not disallowed)
249 				 */
250 				afree(t, ATEMP);
251 				if (XPsize(args) == 0 && XPsize(vars) == 0) {
252 					reject = false;
253 					goto Subshell;
254 				}
255 				/* Must be a function */
256 				if (iopn != 0 || XPsize(args) != 1 ||
257 				    XPsize(vars) != 0)
258 					syntaxerr(NULL);
259 				reject = false;
260 				/*(*/
261 				musthave(')', 0);
262 				t = function_body(XPptrv(args)[0], false);
263 				goto Leave;
264 
265 			default:
266 				goto Leave;
267 			}
268 		}
269 	  Leave:
270 		break;
271 
272 	  Subshell:
273 	case '(':
274 		t = nested(TPAREN, '(', ')');
275 		break;
276 
277 	case '{': /*}*/
278 		t = nested(TBRACE, '{', '}');
279 		break;
280 
281 	case MDPAREN:
282 	  {
283 		static const char let_cmd[] = {
284 			CHAR, 'l', CHAR, 'e',
285 			CHAR, 't', EOS
286 		};
287 		/* Leave KEYWORD in syniocf (allow if (( 1 )) then ...) */
288 		t = newtp(TCOM);
289 		t->lineno = source->line;
290 		reject = false;
291 		XPput(args, wdcopy(let_cmd, ATEMP));
292 		musthave(LWORD,LETEXPR);
293 		XPput(args, yylval.cp);
294 		break;
295 	  }
296 
297 	case DBRACKET: /* [[ .. ]] */
298 		/* Leave KEYWORD in syniocf (allow if [[ -n 1 ]] then ...) */
299 		t = newtp(TDBRACKET);
300 		reject = false;
301 		{
302 			Test_env te;
303 
304 			te.flags = TEF_DBRACKET;
305 			te.pos.av = &args;
306 			te.isa = dbtestp_isa;
307 			te.getopnd = dbtestp_getopnd;
308 			te.eval = dbtestp_eval;
309 			te.error = dbtestp_error;
310 
311 			test_parse(&te);
312 		}
313 		break;
314 
315 	case FOR:
316 	case SELECT:
317 		t = newtp((c == FOR) ? TFOR : TSELECT);
318 		musthave(LWORD, ARRAYVAR);
319 		if (!is_wdvarname(yylval.cp, true))
320 			yyerror("%s: bad identifier\n",
321 			    c == FOR ? "for" : "select");
322 		t->str = str_save(ident, ATEMP);
323 		nesting_push(&old_nesting, c);
324 		t->vars = wordlist();
325 		t->left = dogroup();
326 		nesting_pop(&old_nesting);
327 		break;
328 
329 	case WHILE:
330 	case UNTIL:
331 		nesting_push(&old_nesting, c);
332 		t = newtp((c == WHILE) ? TWHILE : TUNTIL);
333 		t->left = c_list(true);
334 		if (t->left == NULL)
335 			syntaxerr(NULL);
336 		t->right = dogroup();
337 		nesting_pop(&old_nesting);
338 		break;
339 
340 	case CASE:
341 		t = newtp(TCASE);
342 		musthave(LWORD, 0);
343 		t->str = yylval.cp;
344 		nesting_push(&old_nesting, c);
345 		t->left = caselist();
346 		nesting_pop(&old_nesting);
347 		break;
348 
349 	case IF:
350 		nesting_push(&old_nesting, c);
351 		t = newtp(TIF);
352 		t->left = c_list(true);
353 		t->right = thenpart();
354 		musthave(FI, KEYWORD|ALIAS);
355 		nesting_pop(&old_nesting);
356 		break;
357 
358 	case BANG:
359 		syniocf &= ~(KEYWORD|ALIAS);
360 		t = pipeline(0);
361 		if (t == NULL)
362 			syntaxerr(NULL);
363 		t = block(TBANG, NULL, t, NULL);
364 		break;
365 
366 	case TIME:
367 		syniocf &= ~(KEYWORD|ALIAS);
368 		t = pipeline(0);
369 		if (t) {
370 			if (t->str) {
371 				t->str = str_save(t->str, ATEMP);
372 			} else {
373 				t->str = alloc(2, ATEMP);
374 				t->str[0] = '\0'; /* TF_* flags */
375 				t->str[1] = '\0';
376 			}
377 		}
378 		t = block(TTIME, t, NULL, NULL);
379 		break;
380 
381 	case FUNCTION:
382 		musthave(LWORD, 0);
383 		t = function_body(yylval.cp, true);
384 		break;
385 	}
386 
387 	while ((iop = synio(syniocf)) != NULL) {
388 		if (iopn >= NUFILE)
389 			yyerror("too many redirections\n");
390 		iops[iopn++] = iop;
391 	}
392 
393 	if (iopn == 0) {
394 		afree(iops, ATEMP);
395 		t->ioact = NULL;
396 	} else {
397 		iops[iopn++] = NULL;
398 		iops = areallocarray(iops, iopn,
399 		    sizeof(struct ioword *), ATEMP);
400 		t->ioact = iops;
401 	}
402 
403 	if (t->type == TCOM || t->type == TDBRACKET) {
404 		XPput(args, NULL);
405 		t->args = (char **) XPclose(args);
406 		XPput(vars, NULL);
407 		t->vars = (char **) XPclose(vars);
408 	} else {
409 		XPfree(args);
410 		XPfree(vars);
411 	}
412 
413 	return t;
414 }
415 
416 static struct op *
dogroup(void)417 dogroup(void)
418 {
419 	int c;
420 	struct op *list;
421 
422 	c = token(CONTIN|KEYWORD|ALIAS);
423 	/* A {...} can be used instead of do...done for for/select loops
424 	 * but not for while/until loops - we don't need to check if it
425 	 * is a while loop because it would have been parsed as part of
426 	 * the conditional command list...
427 	 */
428 	if (c == DO)
429 		c = DONE;
430 	else if (c == '{')
431 		c = '}';
432 	else
433 		syntaxerr(NULL);
434 	list = c_list(true);
435 	musthave(c, KEYWORD|ALIAS);
436 	return list;
437 }
438 
439 static struct op *
thenpart(void)440 thenpart(void)
441 {
442 	struct op *t;
443 
444 	musthave(THEN, KEYWORD|ALIAS);
445 	t = newtp(0);
446 	t->left = c_list(true);
447 	if (t->left == NULL)
448 		syntaxerr(NULL);
449 	t->right = elsepart();
450 	return (t);
451 }
452 
453 static struct op *
elsepart(void)454 elsepart(void)
455 {
456 	struct op *t;
457 
458 	switch (token(KEYWORD|ALIAS|VARASN)) {
459 	case ELSE:
460 		if ((t = c_list(true)) == NULL)
461 			syntaxerr(NULL);
462 		return (t);
463 
464 	case ELIF:
465 		t = newtp(TELIF);
466 		t->left = c_list(true);
467 		t->right = thenpart();
468 		return (t);
469 
470 	default:
471 		reject = true;
472 	}
473 	return NULL;
474 }
475 
476 static struct op *
caselist(void)477 caselist(void)
478 {
479 	struct op *t, *tl;
480 	int c;
481 
482 	c = token(CONTIN|KEYWORD|ALIAS);
483 	/* A {...} can be used instead of in...esac for case statements */
484 	if (c == IN)
485 		c = ESAC;
486 	else if (c == '{')
487 		c = '}';
488 	else
489 		syntaxerr(NULL);
490 	t = tl = NULL;
491 	while ((tpeek(CONTIN|KEYWORD|ESACONLY)) != c) { /* no ALIAS here */
492 		struct op *tc = casepart(c);
493 		if (tl == NULL)
494 			t = tl = tc, tl->right = NULL;
495 		else
496 			tl->right = tc, tl = tc;
497 	}
498 	musthave(c, KEYWORD|ALIAS);
499 	return (t);
500 }
501 
502 static struct op *
casepart(int endtok)503 casepart(int endtok)
504 {
505 	struct op *t;
506 	int c;
507 	XPtrV ptns;
508 
509 	XPinit(ptns, 16);
510 	t = newtp(TPAT);
511 	c = token(CONTIN|KEYWORD); /* no ALIAS here */
512 	if (c != '(')
513 		reject = true;
514 	do {
515 		musthave(LWORD, 0);
516 		XPput(ptns, yylval.cp);
517 	} while ((c = token(0)) == '|');
518 	reject = true;
519 	XPput(ptns, NULL);
520 	t->vars = (char **) XPclose(ptns);
521 	musthave(')', 0);
522 
523 	t->left = c_list(true);
524 	/* Note: Posix requires the ;; */
525 	if ((tpeek(CONTIN|KEYWORD|ALIAS)) != endtok)
526 		musthave(BREAK, CONTIN|KEYWORD|ALIAS);
527 	return (t);
528 }
529 
530 static struct op *
function_body(char * name,int ksh_func)531 function_body(char *name,
532     int ksh_func)		/* function foo { ... } vs foo() { .. } */
533 {
534 	char *sname, *p;
535 	struct op *t;
536 	int old_func_parse;
537 
538 	sname = wdstrip(name);
539 	/* Check for valid characters in name.  posix and ksh93 say only
540 	 * allow [a-zA-Z_0-9] but this allows more as old pdksh's have
541 	 * allowed more (the following were never allowed:
542 	 *	nul space nl tab $ ' " \ ` ( ) & | ; = < >
543 	 *  C_QUOTE covers all but = and adds # [ ? *)
544 	 */
545 	for (p = sname; *p; p++)
546 		if (ctype(*p, C_QUOTE) || *p == '=')
547 			yyerror("%s: invalid function name\n", sname);
548 
549 	t = newtp(TFUNCT);
550 	t->str = sname;
551 	t->u.ksh_func = ksh_func;
552 	t->lineno = source->line;
553 
554 	/* Note that POSIX allows only compound statements after foo(), sh and
555 	 * at&t ksh allow any command, go with the later since it shouldn't
556 	 * break anything.  However, for function foo, at&t ksh only accepts
557 	 * an open-brace.
558 	 */
559 	if (ksh_func) {
560 		musthave('{', CONTIN|KEYWORD|ALIAS); /* } */
561 		reject = true;
562 	}
563 
564 	old_func_parse = genv->flags & EF_FUNC_PARSE;
565 	genv->flags |= EF_FUNC_PARSE;
566 	if ((t->left = get_command(CONTIN)) == NULL) {
567 		/*
568 		 * Probably something like foo() followed by eof or ;.
569 		 * This is accepted by sh and ksh88.
570 		 * To make "typeset -f foo" work reliably (so its output can
571 		 * be used as input), we pretend there is a colon here.
572 		 */
573 		t->left = newtp(TCOM);
574 		t->left->args = areallocarray(NULL, 2, sizeof(char *), ATEMP);
575 		t->left->args[0] = alloc(3, ATEMP);
576 		t->left->args[0][0] = CHAR;
577 		t->left->args[0][1] = ':';
578 		t->left->args[0][2] = EOS;
579 		t->left->args[1] = NULL;
580 		t->left->vars = alloc(sizeof(char *), ATEMP);
581 		t->left->vars[0] = NULL;
582 		t->left->lineno = 1;
583 	}
584 	if (!old_func_parse)
585 		genv->flags &= ~EF_FUNC_PARSE;
586 
587 	return t;
588 }
589 
590 static char **
wordlist(void)591 wordlist(void)
592 {
593 	int c;
594 	XPtrV args;
595 
596 	XPinit(args, 16);
597 	/* Posix does not do alias expansion here... */
598 	if ((c = token(CONTIN|KEYWORD|ALIAS)) != IN) {
599 		if (c != ';') /* non-POSIX, but at&t ksh accepts a ; here */
600 			reject = true;
601 		return NULL;
602 	}
603 	while ((c = token(0)) == LWORD)
604 		XPput(args, yylval.cp);
605 	if (c != '\n' && c != ';')
606 		syntaxerr(NULL);
607 	XPput(args, NULL);
608 	return (char **) XPclose(args);
609 }
610 
611 /*
612  * supporting functions
613  */
614 
615 static struct op *
block(int type,struct op * t1,struct op * t2,char ** wp)616 block(int type, struct op *t1, struct op *t2, char **wp)
617 {
618 	struct op *t;
619 
620 	t = newtp(type);
621 	t->left = t1;
622 	t->right = t2;
623 	t->vars = wp;
624 	return (t);
625 }
626 
627 const	struct tokeninfo {
628 	const char *name;
629 	short	val;
630 	short	reserved;
631 } tokentab[] = {
632 	/* Reserved words */
633 	{ "if",		IF,	true },
634 	{ "then",	THEN,	true },
635 	{ "else",	ELSE,	true },
636 	{ "elif",	ELIF,	true },
637 	{ "fi",		FI,	true },
638 	{ "case",	CASE,	true },
639 	{ "esac",	ESAC,	true },
640 	{ "for",	FOR,	true },
641 	{ "select",	SELECT,	true },
642 	{ "while",	WHILE,	true },
643 	{ "until",	UNTIL,	true },
644 	{ "do",		DO,	true },
645 	{ "done",	DONE,	true },
646 	{ "in",		IN,	true },
647 	{ "function",	FUNCTION, true },
648 	{ "time",	TIME,	true },
649 	{ "{",		'{',	true },
650 	{ "}",		'}',	true },
651 	{ "!",		BANG,	true },
652 	{ "[[",		DBRACKET, true },
653 	/* Lexical tokens (0[EOF], LWORD and REDIR handled specially) */
654 	{ "&&",		LOGAND,	false },
655 	{ "||",		LOGOR,	false },
656 	{ ";;",		BREAK,	false },
657 	{ "((",		MDPAREN, false },
658 	{ "|&",		COPROC,	false },
659 	/* and some special cases... */
660 	{ "newline",	'\n',	false },
661 	{ 0 }
662 };
663 
664 void
initkeywords(void)665 initkeywords(void)
666 {
667 	struct tokeninfo const *tt;
668 	struct tbl *p;
669 
670 	ktinit(&keywords, APERM, 32); /* must be 2^n (currently 20 keywords) */
671 	for (tt = tokentab; tt->name; tt++) {
672 		if (tt->reserved) {
673 			p = ktenter(&keywords, tt->name, hash(tt->name));
674 			p->flag |= DEFINED|ISSET;
675 			p->type = CKEYWD;
676 			p->val.i = tt->val;
677 		}
678 	}
679 }
680 
681 static void
syntaxerr(const char * what)682 syntaxerr(const char *what)
683 {
684 	char redir[6];	/* 2<<- is the longest redirection, I think */
685 	const char *s;
686 	struct tokeninfo const *tt;
687 	int c;
688 
689 	if (!what)
690 		what = "unexpected";
691 	reject = true;
692 	c = token(0);
693     Again:
694 	switch (c) {
695 	case 0:
696 		if (nesting.start_token) {
697 			c = nesting.start_token;
698 			source->errline = nesting.start_line;
699 			what = "unmatched";
700 			goto Again;
701 		}
702 		/* don't quote the EOF */
703 		yyerror("syntax error: unexpected EOF\n");
704 		/* NOTREACHED */
705 
706 	case LWORD:
707 		s = snptreef(NULL, 32, "%S", yylval.cp);
708 		break;
709 
710 	case REDIR:
711 		s = snptreef(redir, sizeof(redir), "%R", yylval.iop);
712 		break;
713 
714 	default:
715 		for (tt = tokentab; tt->name; tt++)
716 			if (tt->val == c)
717 			    break;
718 		if (tt->name)
719 			s = tt->name;
720 		else {
721 			if (c > 0 && c < 256) {
722 				redir[0] = c;
723 				redir[1] = '\0';
724 			} else
725 				shf_snprintf(redir, sizeof(redir),
726 					"?%d", c);
727 			s = redir;
728 		}
729 	}
730 	yyerror("syntax error: `%s' %s\n", s, what);
731 }
732 
733 static void
nesting_push(struct nesting_state * save,int tok)734 nesting_push(struct nesting_state *save, int tok)
735 {
736 	*save = nesting;
737 	nesting.start_token = tok;
738 	nesting.start_line = source->line;
739 }
740 
741 static void
nesting_pop(struct nesting_state * saved)742 nesting_pop(struct nesting_state *saved)
743 {
744 	nesting = *saved;
745 }
746 
747 static struct op *
newtp(int type)748 newtp(int type)
749 {
750 	struct op *t;
751 
752 	t = alloc(sizeof(*t), ATEMP);
753 	t->type = type;
754 	t->u.evalflags = 0;
755 	t->args = t->vars = NULL;
756 	t->ioact = NULL;
757 	t->left = t->right = NULL;
758 	t->str = NULL;
759 	return (t);
760 }
761 
762 struct op *
compile(Source * s)763 compile(Source *s)
764 {
765 	nesting.start_token = 0;
766 	nesting.start_line = 0;
767 	herep = heres;
768 	source = s;
769 	yyparse();
770 	return outtree;
771 }
772 
773 /* This kludge exists to take care of sh/at&t ksh oddity in which
774  * the arguments of alias/export/readonly/typeset have no field
775  * splitting, file globbing, or (normal) tilde expansion done.
776  * at&t ksh seems to do something similar to this since
777  *	$ touch a=a; typeset a=[ab]; echo "$a"
778  *	a=[ab]
779  *	$ x=typeset; $x a=[ab]; echo "$a"
780  *	a=a
781  *	$
782  */
783 static int
assign_command(char * s)784 assign_command(char *s)
785 {
786 	if (Flag(FPOSIX) || !*s)
787 		return 0;
788 	return (strcmp(s, "alias") == 0) ||
789 	    (strcmp(s, "export") == 0) ||
790 	    (strcmp(s, "readonly") == 0) ||
791 	    (strcmp(s, "typeset") == 0);
792 }
793 
794 /* Check if we are in the middle of reading an alias */
795 static int
inalias(struct source * s)796 inalias(struct source *s)
797 {
798 	for (; s && s->type == SALIAS; s = s->next)
799 		if (!(s->flags & SF_ALIASEND))
800 			return 1;
801 	return 0;
802 }
803 
804 
805 /* Order important - indexed by Test_meta values
806  * Note that ||, &&, ( and ) can't appear in as unquoted strings
807  * in normal shell input, so these can be interpreted unambiguously
808  * in the evaluation pass.
809  */
810 static const char dbtest_or[] = { CHAR, '|', CHAR, '|', EOS };
811 static const char dbtest_and[] = { CHAR, '&', CHAR, '&', EOS };
812 static const char dbtest_not[] = { CHAR, '!', EOS };
813 static const char dbtest_oparen[] = { CHAR, '(', EOS };
814 static const char dbtest_cparen[] = { CHAR, ')', EOS };
815 const char *const dbtest_tokens[] = {
816 	dbtest_or, dbtest_and, dbtest_not,
817 	dbtest_oparen, dbtest_cparen
818 };
819 const char db_close[] = { CHAR, ']', CHAR, ']', EOS };
820 const char db_lthan[] = { CHAR, '<', EOS };
821 const char db_gthan[] = { CHAR, '>', EOS };
822 
823 /* Test if the current token is a whatever.  Accepts the current token if
824  * it is.  Returns 0 if it is not, non-zero if it is (in the case of
825  * TM_UNOP and TM_BINOP, the returned value is a Test_op).
826  */
827 static int
dbtestp_isa(Test_env * te,Test_meta meta)828 dbtestp_isa(Test_env *te, Test_meta meta)
829 {
830 	int c = tpeek(ARRAYVAR | (meta == TM_BINOP ? 0 : CONTIN));
831 	int uqword = 0;
832 	char *save = NULL;
833 	int ret = 0;
834 
835 	/* unquoted word? */
836 	uqword = c == LWORD && *ident;
837 
838 	if (meta == TM_OR)
839 		ret = c == LOGOR;
840 	else if (meta == TM_AND)
841 		ret = c == LOGAND;
842 	else if (meta == TM_NOT)
843 		ret = uqword && strcmp(yylval.cp, dbtest_tokens[(int) TM_NOT]) == 0;
844 	else if (meta == TM_OPAREN)
845 		ret = c == '(' /*)*/;
846 	else if (meta == TM_CPAREN)
847 		ret = c == /*(*/ ')';
848 	else if (meta == TM_UNOP || meta == TM_BINOP) {
849 		if (meta == TM_BINOP && c == REDIR &&
850 		    (yylval.iop->flag == IOREAD || yylval.iop->flag == IOWRITE)) {
851 			ret = 1;
852 			save = wdcopy(yylval.iop->flag == IOREAD ?
853 			    db_lthan : db_gthan, ATEMP);
854 		} else if (uqword && (ret = (int) test_isop(te, meta, ident)))
855 			save = yylval.cp;
856 	} else /* meta == TM_END */
857 		ret = uqword && strcmp(yylval.cp, db_close) == 0;
858 	if (ret) {
859 		reject = false;
860 		if (meta != TM_END) {
861 			if (!save)
862 				save = wdcopy(dbtest_tokens[(int) meta], ATEMP);
863 			XPput(*te->pos.av, save);
864 		}
865 	}
866 	return ret;
867 }
868 
869 static const char *
dbtestp_getopnd(Test_env * te,Test_op op,int do_eval)870 dbtestp_getopnd(Test_env *te, Test_op op, int do_eval)
871 {
872 	int c = tpeek(ARRAYVAR);
873 
874 	if (c != LWORD)
875 		return NULL;
876 
877 	reject = false;
878 	XPput(*te->pos.av, yylval.cp);
879 
880 	return null;
881 }
882 
883 static int
dbtestp_eval(Test_env * te,Test_op op,const char * opnd1,const char * opnd2,int do_eval)884 dbtestp_eval(Test_env *te, Test_op op, const char *opnd1, const char *opnd2,
885     int do_eval)
886 {
887 	return 1;
888 }
889 
890 static void
dbtestp_error(Test_env * te,int offset,const char * msg)891 dbtestp_error(Test_env *te, int offset, const char *msg)
892 {
893 	te->flags |= TEF_ERROR;
894 
895 	if (offset < 0) {
896 		reject = true;
897 		/* Kludgy to say the least... */
898 		symbol = LWORD;
899 		yylval.cp = *(XPptrv(*te->pos.av) + XPsize(*te->pos.av) +
900 		    offset);
901 	}
902 	syntaxerr(msg);
903 }
904