xref: /plan9/sys/src/ape/cmd/pdksh/syn.c (revision 7dd7cddf99dd7472612f1413b4da293630e6b1bc)
1 /*
2  * shell parser (C version)
3  */
4 
5 #include "sh.h"
6 #include "c_test.h"
7 
8 struct nesting_state {
9 	int	start_token;	/* token than began nesting (eg, FOR) */
10 	int	start_line;	/* line nesting began on */
11 };
12 
13 static void	yyparse		ARGS((void));
14 static struct op *pipeline	ARGS((int cf));
15 static struct op *andor		ARGS((void));
16 static struct op *c_list	ARGS((int multi));
17 static struct ioword *synio	ARGS((int cf));
18 static void	musthave	ARGS((int c, int cf));
19 static struct op *nested	ARGS((int type, int smark, int emark));
20 static struct op *get_command	ARGS((int cf));
21 static struct op *dogroup	ARGS((void));
22 static struct op *thenpart	ARGS((void));
23 static struct op *elsepart	ARGS((void));
24 static struct op *caselist	ARGS((void));
25 static struct op *casepart	ARGS((int endtok));
26 static struct op *function_body	ARGS((char *name, int ksh_func));
27 static char **	wordlist	ARGS((void));
28 static struct op *block		ARGS((int type, struct op *t1, struct op *t2,
29 				      char **wp));
30 static struct op *newtp		ARGS((int type));
31 static void	syntaxerr	ARGS((const char *what))
32 						GCC_FUNC_ATTR(noreturn);
33 static void	nesting_push ARGS((struct nesting_state *save, int tok));
34 static void	nesting_pop ARGS((struct nesting_state *saved));
35 static int	assign_command ARGS((char *s));
36 static int	inalias ARGS((struct source *s));
37 #ifdef KSH
38 static int	dbtestp_isa ARGS((Test_env *te, Test_meta meta));
39 static const char *dbtestp_getopnd ARGS((Test_env *te, Test_op op,
40 					int do_eval));
41 static int	dbtestp_eval ARGS((Test_env *te, Test_op op, const char *opnd1,
42 				const char *opnd2, int do_eval));
43 static void	dbtestp_error ARGS((Test_env *te, int offset, const char *msg));
44 #endif /* KSH */
45 
46 static	struct	op	*outtree; /* yyparse output */
47 
48 static struct nesting_state nesting;	/* \n changed to ; */
49 
50 static	int	reject;		/* token(cf) gets symbol again */
51 static	int	symbol;		/* yylex value */
52 
53 #define	REJECT	(reject = 1)
54 #define	ACCEPT	(reject = 0)
55 #define	token(cf) \
56 	((reject) ? (ACCEPT, symbol) : (symbol = yylex(cf)))
57 #define	tpeek(cf) \
58 	((reject) ? (symbol) : (REJECT, symbol = yylex(cf)))
59 
60 static void
yyparse()61 yyparse()
62 {
63 	int c;
64 
65 	ACCEPT;
66 
67 	outtree = c_list(source->type == SSTRING);
68 	c = tpeek(0);
69 	if (c == 0 && !outtree)
70 		outtree = newtp(TEOF);
71 	else if (c != '\n' && c != 0)
72 		syntaxerr((char *) 0);
73 }
74 
75 static struct op *
pipeline(cf)76 pipeline(cf)
77 	int cf;
78 {
79 	register struct op *t, *p, *tl = NULL;
80 
81 	t = get_command(cf);
82 	if (t != NULL) {
83 		while (token(0) == '|') {
84 			if ((p = get_command(CONTIN)) == NULL)
85 				syntaxerr((char *) 0);
86 			if (tl == NULL)
87 				t = tl = block(TPIPE, t, p, NOWORDS);
88 			else
89 				tl = tl->right = block(TPIPE, tl->right, p, NOWORDS);
90 		}
91 		REJECT;
92 	}
93 	return (t);
94 }
95 
96 static struct op *
andor()97 andor()
98 {
99 	register struct op *t, *p;
100 	register int c;
101 
102 	t = pipeline(0);
103 	if (t != NULL) {
104 		while ((c = token(0)) == LOGAND || c == LOGOR) {
105 			if ((p = pipeline(CONTIN)) == NULL)
106 				syntaxerr((char *) 0);
107 			t = block(c == LOGAND? TAND: TOR, t, p, NOWORDS);
108 		}
109 		REJECT;
110 	}
111 	return (t);
112 }
113 
114 static struct op *
c_list(multi)115 c_list(multi)
116 	int multi;
117 {
118 	register struct op *t = NULL, *p, *tl = NULL;
119 	register int c;
120 	int have_sep;
121 
122 	while (1) {
123 		p = andor();
124 		/* Token has always been read/rejected at this point, so
125 		 * we don't worry about what flags to pass token()
126 		 */
127 		c = token(0);
128 		have_sep = 1;
129 		if (c == '\n' && (multi || inalias(source))) {
130 			if (!p) /* ignore blank lines */
131 				continue;
132 		} else if (!p)
133 			break;
134 		else if (c == '&' || c == COPROC)
135 			p = block(c == '&' ? TASYNC : TCOPROC,
136 				  p, NOBLOCK, NOWORDS);
137 		else if (c != ';')
138 			have_sep = 0;
139 		if (!t)
140 			t = p;
141 		else if (!tl)
142 			t = tl = block(TLIST, t, p, NOWORDS);
143 		else
144 			tl = tl->right = block(TLIST, tl->right, p, NOWORDS);
145 		if (!have_sep)
146 			break;
147 	}
148 	REJECT;
149 	return t;
150 }
151 
152 static struct ioword *
synio(cf)153 synio(cf)
154 	int cf;
155 {
156 	register struct ioword *iop;
157 	int ishere;
158 
159 	if (tpeek(cf) != REDIR)
160 		return NULL;
161 	ACCEPT;
162 	iop = yylval.iop;
163 	ishere = (iop->flag&IOTYPE) == IOHERE;
164 	musthave(LWORD, ishere ? HEREDELIM : 0);
165 	if (ishere) {
166 		iop->delim = yylval.cp;
167 		if (*ident != 0) /* unquoted */
168 			iop->flag |= IOEVAL;
169 		if (herep >= &heres[HERES])
170 			yyerror("too many <<'s\n");
171 		*herep++ = iop;
172 	} else
173 		iop->name = yylval.cp;
174 	return iop;
175 }
176 
177 static void
musthave(c,cf)178 musthave(c, cf)
179 	int c, cf;
180 {
181 	if ((token(cf)) != c)
182 		syntaxerr((char *) 0);
183 }
184 
185 static struct op *
nested(type,smark,emark)186 nested(type, smark, emark)
187 	int type, smark, emark;
188 {
189 	register struct op *t;
190 	struct nesting_state old_nesting;
191 
192 	nesting_push(&old_nesting, smark);
193 	t = c_list(TRUE);
194 	musthave(emark, KEYWORD|ALIAS);
195 	nesting_pop(&old_nesting);
196 	return (block(type, t, NOBLOCK, NOWORDS));
197 }
198 
199 static struct op *
get_command(cf)200 get_command(cf)
201 	int cf;
202 {
203 	register struct op *t;
204 	register int c, iopn = 0, syniocf;
205 	struct ioword *iop, **iops;
206 	XPtrV args, vars;
207 	struct nesting_state old_nesting;
208 
209 	iops = (struct ioword **) alloc(sizeofN(struct ioword *, NUFILE+1),
210 					ATEMP);
211 	XPinit(args, 16);
212 	XPinit(vars, 16);
213 
214 	syniocf = KEYWORD|ALIAS;
215 	switch (c = token(cf|KEYWORD|ALIAS|VARASN)) {
216 	  default:
217 		REJECT;
218 		afree((void*) iops, ATEMP);
219 		XPfree(args);
220 		XPfree(vars);
221 		return NULL; /* empty line */
222 
223 	  case LWORD:
224 	  case REDIR:
225 		REJECT;
226 		syniocf &= ~(KEYWORD|ALIAS);
227 		t = newtp(TCOM);
228 		t->lineno = source->line;
229 		while (1) {
230 			cf = (t->u.evalflags ? ARRAYVAR : 0)
231 			     | (XPsize(args) == 0 ? ALIAS|VARASN : CMDWORD);
232 			switch (tpeek(cf)) {
233 			  case REDIR:
234 				if (iopn >= NUFILE)
235 					yyerror("too many redirections\n");
236 				iops[iopn++] = synio(cf);
237 				break;
238 
239 			  case LWORD:
240 				ACCEPT;
241 				/* the iopn == 0 and XPsize(vars) == 0 are
242 				 * dubious but at&t ksh acts this way
243 				 */
244 				if (iopn == 0 && XPsize(vars) == 0
245 				    && XPsize(args) == 0
246 				    && assign_command(ident))
247 					t->u.evalflags = DOVACHECK;
248 				if ((XPsize(args) == 0 || Flag(FKEYWORD))
249 				    && is_wdvarassign(yylval.cp))
250 					XPput(vars, yylval.cp);
251 				else
252 					XPput(args, yylval.cp);
253 				break;
254 
255 			  case '(':
256 				/* Check for "> foo (echo hi)", which at&t ksh
257 				 * allows (not POSIX, but not disallowed)
258 				 */
259 				afree(t, ATEMP);
260 				if (XPsize(args) == 0 && XPsize(vars) == 0) {
261 					ACCEPT;
262 					goto Subshell;
263 				}
264 				/* Must be a function */
265 				if (iopn != 0 || XPsize(args) != 1
266 				    || XPsize(vars) != 0)
267 					syntaxerr((char *) 0);
268 				ACCEPT;
269 				/*(*/
270 				musthave(')', 0);
271 				t = function_body(XPptrv(args)[0], FALSE);
272 				goto Leave;
273 
274 			  default:
275 				goto Leave;
276 			}
277 		}
278 	  Leave:
279 		break;
280 
281 	  Subshell:
282 	  case '(':
283 		t = nested(TPAREN, '(', ')');
284 		break;
285 
286 	  case '{': /*}*/
287 		t = nested(TBRACE, '{', '}');
288 		break;
289 
290 #ifdef KSH
291 	  case MDPAREN:
292 	  {
293 		static const char let_cmd[] = { CHAR, 'l', CHAR, 'e',
294 						CHAR, 't', EOS };
295 		/* Leave KEYWORD in syniocf (allow if (( 1 )) then ...) */
296 		t = newtp(TCOM);
297 		t->lineno = source->line;
298 		ACCEPT;
299 		XPput(args, wdcopy(let_cmd, ATEMP));
300 		musthave(LWORD,LETEXPR);
301 		XPput(args, yylval.cp);
302 		break;
303 	  }
304 #endif /* KSH */
305 
306 #ifdef KSH
307 	  case DBRACKET: /* [[ .. ]] */
308 		/* Leave KEYWORD in syniocf (allow if [[ -n 1 ]] then ...) */
309 		t = newtp(TDBRACKET);
310 		ACCEPT;
311 		{
312 			Test_env te;
313 
314 			te.flags = TEF_DBRACKET;
315 			te.pos.av = &args;
316 			te.isa = dbtestp_isa;
317 			te.getopnd = dbtestp_getopnd;
318 			te.eval = dbtestp_eval;
319 			te.error = dbtestp_error;
320 
321 			test_parse(&te);
322 		}
323 		break;
324 #endif /* KSH */
325 
326 	  case FOR:
327 	  case SELECT:
328 		t = newtp((c == FOR) ? TFOR : TSELECT);
329 		musthave(LWORD, ARRAYVAR);
330 		if (!is_wdvarname(yylval.cp, TRUE))
331 			yyerror("%s: bad identifier\n",
332 				c == FOR ? "for" : "select");
333 		t->str = str_save(ident, ATEMP);
334 		nesting_push(&old_nesting, c);
335 		t->vars = wordlist();
336 		t->left = dogroup();
337 		nesting_pop(&old_nesting);
338 		break;
339 
340 	  case WHILE:
341 	  case UNTIL:
342 		nesting_push(&old_nesting, c);
343 		t = newtp((c == WHILE) ? TWHILE : TUNTIL);
344 		t->left = c_list(TRUE);
345 		t->right = dogroup();
346 		nesting_pop(&old_nesting);
347 		break;
348 
349 	  case CASE:
350 		t = newtp(TCASE);
351 		musthave(LWORD, 0);
352 		t->str = yylval.cp;
353 		nesting_push(&old_nesting, c);
354 		t->left = caselist();
355 		nesting_pop(&old_nesting);
356 		break;
357 
358 	  case IF:
359 		nesting_push(&old_nesting, c);
360 		t = newtp(TIF);
361 		t->left = c_list(TRUE);
362 		t->right = thenpart();
363 		musthave(FI, KEYWORD|ALIAS);
364 		nesting_pop(&old_nesting);
365 		break;
366 
367 	  case BANG:
368 		syniocf &= ~(KEYWORD|ALIAS);
369 		t = pipeline(0);
370 		if (t == (struct op *) 0)
371 			syntaxerr((char *) 0);
372 		t = block(TBANG, NOBLOCK, t, NOWORDS);
373 		break;
374 
375 	  case TIME:
376 		syniocf &= ~(KEYWORD|ALIAS);
377 		t = pipeline(0);
378 		t = block(TTIME, t, NOBLOCK, NOWORDS);
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((void*) iops, ATEMP);
395 		t->ioact = NULL;
396 	} else {
397 		iops[iopn++] = NULL;
398 		iops = (struct ioword **) aresize((void*) iops,
399 					sizeofN(struct ioword *, iopn), 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()417 dogroup()
418 {
419 	register int c;
420 	register 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((char *) 0);
434 	list = c_list(TRUE);
435 	musthave(c, KEYWORD|ALIAS);
436 	return list;
437 }
438 
439 static struct op *
thenpart()440 thenpart()
441 {
442 	register 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((char *) 0);
449 	t->right = elsepart();
450 	return (t);
451 }
452 
453 static struct op *
elsepart()454 elsepart()
455 {
456 	register struct op *t;
457 
458 	switch (token(KEYWORD|ALIAS|VARASN)) {
459 	  case ELSE:
460 		if ((t = c_list(TRUE)) == NULL)
461 			syntaxerr((char *) 0);
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;
472 	}
473 	return NULL;
474 }
475 
476 static struct op *
caselist()477 caselist()
478 {
479 	register 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((char *) 0);
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(endtok)503 casepart(endtok)
504 	int endtok;
505 {
506 	register struct op *t;
507 	register int c;
508 	XPtrV ptns;
509 
510 	XPinit(ptns, 16);
511 	t = newtp(TPAT);
512 	c = token(CONTIN|KEYWORD); /* no ALIAS here */
513 	if (c != '(')
514 		REJECT;
515 	do {
516 		musthave(LWORD, 0);
517 		XPput(ptns, yylval.cp);
518 	} while ((c = token(0)) == '|');
519 	REJECT;
520 	XPput(ptns, NULL);
521 	t->vars = (char **) XPclose(ptns);
522 	musthave(')', 0);
523 
524 	t->left = c_list(TRUE);
525 	/* Note: Posix requires the ;; */
526 	if ((tpeek(CONTIN|KEYWORD|ALIAS)) != endtok)
527 		musthave(BREAK, CONTIN|KEYWORD|ALIAS);
528 	return (t);
529 }
530 
531 static struct op *
function_body(name,ksh_func)532 function_body(name, ksh_func)
533 	char *name;
534 	int ksh_func;	/* function foo { ... } vs foo() { .. } */
535 {
536 	char *sname, *p;
537 	struct op *t;
538 	int old_func_parse;
539 
540 	sname = wdstrip(name);
541 	/* Check for valid characters in name.  posix and ksh93 say only
542 	 * allow [a-zA-Z_0-9] but this allows more as old pdksh's have
543 	 * allowed more (the following were never allowed:
544 	 *	nul space nl tab $ ' " \ ` ( ) & | ; = < >
545 	 *  C_QUOTE covers all but = and adds # [ ? *)
546 	 */
547 	for (p = sname; *p; p++)
548 		if (ctype(*p, C_QUOTE) || *p == '=')
549 			yyerror("%s: invalid function name\n", sname);
550 
551 	t = newtp(TFUNCT);
552 	t->str = sname;
553 	t->u.ksh_func = ksh_func;
554 	t->lineno = source->line;
555 
556 	/* Note that POSIX allows only compound statements after foo(), sh and
557 	 * at&t ksh allow any command, go with the later since it shouldn't
558 	 * break anything.  However, for function foo, at&t ksh only accepts
559 	 * an open-brace.
560 	 */
561 	if (ksh_func) {
562 		musthave('{', CONTIN|KEYWORD|ALIAS); /* } */
563 		REJECT;
564 	}
565 
566 	old_func_parse = e->flags & EF_FUNC_PARSE;
567 	e->flags |= EF_FUNC_PARSE;
568 	if ((t->left = get_command(CONTIN)) == (struct op *) 0) {
569 		/*
570 		 * Probably something like foo() followed by eof or ;.
571 		 * This is accepted by sh and ksh88.
572 		 * To make "typset -f foo" work reliably (so its output can
573 		 * be used as input), we pretend there is a colon here.
574 		 */
575 		t->left = newtp(TCOM);
576 		t->left->args = (char **) alloc(sizeof(char *) * 2, ATEMP);
577 		t->left->args[0] = alloc(sizeof(char) * 3, ATEMP);
578 		t->left->args[0][0] = CHAR;
579 		t->left->args[0][1] = ':';
580 		t->left->args[0][2] = EOS;
581 		t->left->args[1] = (char *) 0;
582 		t->left->vars = (char **) alloc(sizeof(char *), ATEMP);
583 		t->left->vars[0] = (char *) 0;
584 		t->left->lineno = 1;
585 	}
586 	if (!old_func_parse)
587 		e->flags &= ~EF_FUNC_PARSE;
588 
589 	return t;
590 }
591 
592 static char **
wordlist()593 wordlist()
594 {
595 	register int c;
596 	XPtrV args;
597 
598 	XPinit(args, 16);
599 	/* Posix does not do alias expansion here... */
600 	if ((c = token(CONTIN|KEYWORD|ALIAS)) != IN) {
601 		if (c != ';') /* non-POSIX, but at&t ksh accepts a ; here */
602 			REJECT;
603 		return NULL;
604 	}
605 	while ((c = token(0)) == LWORD)
606 		XPput(args, yylval.cp);
607 	if (c != '\n' && c != ';')
608 		syntaxerr((char *) 0);
609 	if (XPsize(args) == 0) {
610 		XPfree(args);
611 		return NULL;
612 	} else {
613 		XPput(args, NULL);
614 		return (char **) XPclose(args);
615 	}
616 }
617 
618 /*
619  * supporting functions
620  */
621 
622 static struct op *
block(type,t1,t2,wp)623 block(type, t1, t2, wp)
624 	int type;
625 	struct op *t1, *t2;
626 	char **wp;
627 {
628 	register struct op *t;
629 
630 	t = newtp(type);
631 	t->left = t1;
632 	t->right = t2;
633 	t->vars = wp;
634 	return (t);
635 }
636 
637 const	struct tokeninfo {
638 	const char *name;
639 	short	val;
640 	short	reserved;
641 } tokentab[] = {
642 	/* Reserved words */
643 	{ "if",		IF,	TRUE },
644 	{ "then",	THEN,	TRUE },
645 	{ "else",	ELSE,	TRUE },
646 	{ "elif",	ELIF,	TRUE },
647 	{ "fi",		FI,	TRUE },
648 	{ "case",	CASE,	TRUE },
649 	{ "esac",	ESAC,	TRUE },
650 	{ "for",	FOR,	TRUE },
651 #ifdef KSH
652 	{ "select",	SELECT,	TRUE },
653 #endif /* KSH */
654 	{ "while",	WHILE,	TRUE },
655 	{ "until",	UNTIL,	TRUE },
656 	{ "do",		DO,	TRUE },
657 	{ "done",	DONE,	TRUE },
658 	{ "in",		IN,	TRUE },
659 	{ "function",	FUNCTION, TRUE },
660 	{ "time",	TIME,	TRUE },
661 	{ "{",		'{',	TRUE },
662 	{ "}",		'}',	TRUE },
663 	{ "!",		BANG,	TRUE },
664 #ifdef KSH
665 	{ "[[",		DBRACKET, TRUE },
666 #endif /* KSH */
667 	/* Lexical tokens (0[EOF], LWORD and REDIR handled specially) */
668 	{ "&&",		LOGAND,	FALSE },
669 	{ "||",		LOGOR,	FALSE },
670 	{ ";;",		BREAK,	FALSE },
671 #ifdef KSH
672 	{ "((",		MDPAREN, FALSE },
673 	{ "|&",		COPROC,	FALSE },
674 #endif /* KSH */
675 	/* and some special cases... */
676 	{ "newline",	'\n',	FALSE },
677 	{ 0 }
678 };
679 
680 void
initkeywords()681 initkeywords()
682 {
683 	register struct tokeninfo const *tt;
684 	register struct tbl *p;
685 
686 	tinit(&keywords, APERM, 32); /* must be 2^n (currently 20 keywords) */
687 	for (tt = tokentab; tt->name; tt++) {
688 		if (tt->reserved) {
689 			p = tenter(&keywords, tt->name, hash(tt->name));
690 			p->flag |= DEFINED|ISSET;
691 			p->type = CKEYWD;
692 			p->val.i = tt->val;
693 		}
694 	}
695 }
696 
697 static void
syntaxerr(what)698 syntaxerr(what)
699 	const char *what;
700 {
701 	char redir[6];	/* 2<<- is the longest redirection, I think */
702 	const char *s;
703 	struct tokeninfo const *tt;
704 	int c;
705 
706 	if (!what)
707 		what = "unexpected";
708 	REJECT;
709 	c = token(0);
710     Again:
711 	switch (c) {
712 	case 0:
713 		if (nesting.start_token) {
714 			c = nesting.start_token;
715 			source->errline = nesting.start_line;
716 			what = "unmatched";
717 			goto Again;
718 		}
719 		/* don't quote the EOF */
720 		yyerror("syntax error: unexpected EOF\n");
721 		/*NOTREACHED*/
722 
723 	case LWORD:
724 		s = snptreef((char *) 0, 32, "%S", yylval.cp);
725 		break;
726 
727 	case REDIR:
728 		s = snptreef(redir, sizeof(redir), "%R", yylval.iop);
729 		break;
730 
731 	default:
732 		for (tt = tokentab; tt->name; tt++)
733 			if (tt->val == c)
734 			    break;
735 		if (tt->name)
736 			s = tt->name;
737 		else {
738 			if (c > 0 && c < 256) {
739 				redir[0] = c;
740 				redir[1] = '\0';
741 			} else
742 				shf_snprintf(redir, sizeof(redir),
743 					"?%d", c);
744 			s = redir;
745 		}
746 	}
747 	yyerror("syntax error: `%s' %s\n", s, what);
748 }
749 
750 static void
nesting_push(save,tok)751 nesting_push(save, tok)
752 	struct nesting_state *save;
753 	int tok;
754 {
755 	*save = nesting;
756 	nesting.start_token = tok;
757 	nesting.start_line = source->line;
758 }
759 
760 static void
nesting_pop(saved)761 nesting_pop(saved)
762 	struct nesting_state *saved;
763 {
764 	nesting = *saved;
765 }
766 
767 static struct op *
newtp(type)768 newtp(type)
769 	int type;
770 {
771 	register struct op *t;
772 
773 	t = (struct op *) alloc(sizeof(*t), ATEMP);
774 	t->type = type;
775 	t->u.evalflags = 0;
776 	t->args = t->vars = NULL;
777 	t->ioact = NULL;
778 	t->left = t->right = NULL;
779 	t->str = NULL;
780 	return (t);
781 }
782 
783 struct op *
compile(s)784 compile(s)
785 	Source *s;
786 {
787 	nesting.start_token = 0;
788 	nesting.start_line = 0;
789 	herep = heres;
790 	source = s;
791 	yyparse();
792 	return outtree;
793 }
794 
795 /* This kludge exists to take care of sh/at&t ksh oddity in which
796  * the arguments of alias/export/readonly/typeset have no field
797  * splitting, file globbing, or (normal) tilde expansion done.
798  * at&t ksh seems to do something similar to this since
799  *	$ touch a=a; typeset a=[ab]; echo "$a"
800  *	a=[ab]
801  *	$ x=typeset; $x a=[ab]; echo "$a"
802  *	a=a
803  *	$
804  */
805 static int
assign_command(s)806 assign_command(s)
807 	char *s;
808 {
809 	char c = *s;
810 
811 	if (Flag(FPOSIX) || !*s)
812 		return 0;
813 	return     (c == 'a' && strcmp(s, "alias") == 0)
814 		|| (c == 'e' && strcmp(s, "export") == 0)
815 		|| (c == 'r' && strcmp(s, "readonly") == 0)
816 		|| (c == 't' && strcmp(s, "typeset") == 0);
817 }
818 
819 /* Check if we are in the middle of reading an alias */
820 static int
inalias(s)821 inalias(s)
822 	struct source *s;
823 {
824 	for (; s && s->type == SALIAS; s = s->next)
825 		if (!(s->flags & SF_ALIASEND))
826 			return 1;
827 	return 0;
828 }
829 
830 
831 #ifdef KSH
832 /* Order important - indexed by Test_meta values
833  * Note that ||, &&, ( and ) can't appear in as unquoted strings
834  * in normal shell input, so these can be interpreted unambiguously
835  * in the evaluation pass.
836  */
837 static const char dbtest_or[] = { CHAR, '|', CHAR, '|', EOS };
838 static const char dbtest_and[] = { CHAR, '&', CHAR, '&', EOS };
839 static const char dbtest_not[] = { CHAR, '!', EOS };
840 static const char dbtest_oparen[] = { CHAR, '(', EOS };
841 static const char dbtest_cparen[] = { CHAR, ')', EOS };
842 const char *const dbtest_tokens[] = {
843 			dbtest_or, dbtest_and, dbtest_not,
844 			dbtest_oparen, dbtest_cparen
845 		};
846 const char db_close[] = { CHAR, ']', CHAR, ']', EOS };
847 const char db_lthan[] = { CHAR, '<', EOS };
848 const char db_gthan[] = { CHAR, '>', EOS };
849 
850 /* Test if the current token is a whatever.  Accepts the current token if
851  * it is.  Returns 0 if it is not, non-zero if it is (in the case of
852  * TM_UNOP and TM_BINOP, the returned value is a Test_op).
853  */
854 static int
dbtestp_isa(te,meta)855 dbtestp_isa(te, meta)
856 	Test_env *te;
857 	Test_meta meta;
858 {
859 	int c = tpeek(ARRAYVAR | (meta == TM_BINOP ? 0 : CONTIN));
860 	int uqword = 0;
861 	char *save = (char *) 0;
862 	int ret = 0;
863 
864 	/* unquoted word? */
865 	uqword = c == LWORD && *ident;
866 
867 	if (meta == TM_OR)
868 		ret = c == LOGOR;
869 	else if (meta == TM_AND)
870 		ret = c == LOGAND;
871 	else if (meta == TM_NOT)
872 		ret = uqword && strcmp(yylval.cp, dbtest_tokens[(int) TM_NOT]) == 0;
873 	else if (meta == TM_OPAREN)
874 		ret = c == '(' /*)*/;
875 	else if (meta == TM_CPAREN)
876 		ret = c == /*(*/ ')';
877 	else if (meta == TM_UNOP || meta == TM_BINOP) {
878 		if (meta == TM_BINOP && c == REDIR
879 		    && (yylval.iop->flag == IOREAD
880 			|| yylval.iop->flag == IOWRITE))
881 		{
882 			ret = 1;
883 			save = wdcopy(yylval.iop->flag == IOREAD ?
884 				db_lthan : db_gthan, ATEMP);
885 		} else if (uqword && (ret = (int) test_isop(te, meta, ident)))
886 			save = yylval.cp;
887 	} else /* meta == TM_END */
888 		ret = uqword && strcmp(yylval.cp, db_close) == 0;
889 	if (ret) {
890 		ACCEPT;
891 		if (meta != TM_END) {
892 			if (!save)
893 				save = wdcopy(dbtest_tokens[(int) meta], ATEMP);
894 			XPput(*te->pos.av, save);
895 		}
896 	}
897 	return ret;
898 }
899 
900 static const char *
dbtestp_getopnd(te,op,do_eval)901 dbtestp_getopnd(te, op, do_eval)
902 	Test_env *te;
903 	Test_op op;
904 	int do_eval;
905 {
906 	int c = tpeek(ARRAYVAR);
907 
908 	if (c != LWORD)
909 		return (const char *) 0;
910 
911 	ACCEPT;
912 	XPput(*te->pos.av, yylval.cp);
913 
914 	return null;
915 }
916 
917 static int
dbtestp_eval(te,op,opnd1,opnd2,do_eval)918 dbtestp_eval(te, op, opnd1, opnd2, do_eval)
919 	Test_env *te;
920 	Test_op op;
921 	const char *opnd1;
922 	const char *opnd2;
923 	int do_eval;
924 {
925 	return 1;
926 }
927 
928 static void
dbtestp_error(te,offset,msg)929 dbtestp_error(te, offset, msg)
930 	Test_env *te;
931 	int offset;
932 	const char *msg;
933 {
934 	te->flags |= TEF_ERROR;
935 
936 	if (offset < 0) {
937 		REJECT;
938 		/* Kludgy to say the least... */
939 		symbol = LWORD;
940 		yylval.cp = *(XPptrv(*te->pos.av) + XPsize(*te->pos.av)
941 				+ offset);
942 	}
943 	syntaxerr(msg);
944 }
945 #endif /* KSH */
946