parser.c revision 18200 
1/*-
2 * Copyright (c) 1991, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Kenneth Almquist.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 *	$Id: parser.c,v 1.13 1996/09/03 14:15:57 peter Exp $
37 */
38
39#ifndef lint
40static char sccsid[] = "@(#)parser.c	8.7 (Berkeley) 5/16/95";
41#endif /* not lint */
42
43#include <stdlib.h>
44
45#include "shell.h"
46#include "parser.h"
47#include "nodes.h"
48#include "expand.h"	/* defines rmescapes() */
49#include "redir.h"	/* defines copyfd() */
50#include "syntax.h"
51#include "options.h"
52#include "input.h"
53#include "output.h"
54#include "var.h"
55#include "error.h"
56#include "memalloc.h"
57#include "mystring.h"
58#include "alias.h"
59#include "show.h"
60#ifndef NO_HISTORY
61#include "myhistedit.h"
62#endif
63
64/*
65 * Shell command parser.
66 */
67
68#define EOFMARKLEN 79
69
70/* values returned by readtoken */
71#include "token.h"
72
73
74
75struct heredoc {
76	struct heredoc *next;	/* next here document in list */
77	union node *here;		/* redirection node */
78	char *eofmark;		/* string indicating end of input */
79	int striptabs;		/* if set, strip leading tabs */
80};
81
82
83
84struct heredoc *heredoclist;	/* list of here documents to read */
85int parsebackquote;		/* nonzero if we are inside backquotes */
86int doprompt;			/* if set, prompt the user */
87int needprompt;			/* true if interactive and at start of line */
88int lasttoken;			/* last token read */
89MKINIT int tokpushback;		/* last token pushed back */
90char *wordtext;			/* text of last word returned by readtoken */
91MKINIT int checkkwd;            /* 1 == check for kwds, 2 == also eat newlines */
92struct nodelist *backquotelist;
93union node *redirnode;
94struct heredoc *heredoc;
95int quoteflag;			/* set if (part of) last token was quoted */
96int startlinno;			/* line # where last token started */
97
98/* XXX When 'noaliases' is set to one, no alias expansion takes place. */
99static int noaliases = 0;
100
101#define GDB_HACK 1 /* avoid local declarations which gdb can't handle */
102#ifdef GDB_HACK
103static const char argvars[5] = {CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'};
104static const char types[] = "}-+?=";
105#endif
106
107
108STATIC union node *list __P((int));
109STATIC union node *andor __P((void));
110STATIC union node *pipeline __P((void));
111STATIC union node *command __P((void));
112STATIC union node *simplecmd __P((union node **, union node *));
113STATIC union node *makename __P((void));
114STATIC void parsefname __P((void));
115STATIC void parseheredoc __P((void));
116STATIC int peektoken __P((void));
117STATIC int readtoken __P((void));
118STATIC int xxreadtoken __P((void));
119STATIC int readtoken1 __P((int, char const *, char *, int));
120STATIC int noexpand __P((char *));
121STATIC void synexpect __P((int));
122STATIC void synerror __P((char *));
123STATIC void setprompt __P((int));
124
125
126/*
127 * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
128 * valid parse tree indicating a blank line.)
129 */
130
131union node *
132parsecmd(interact)
133	int interact;
134{
135	int t;
136
137	doprompt = interact;
138	if (doprompt)
139		setprompt(1);
140	else
141		setprompt(0);
142	needprompt = 0;
143	t = readtoken();
144	if (t == TEOF)
145		return NEOF;
146	if (t == TNL)
147		return NULL;
148	tokpushback++;
149	return list(1);
150}
151
152
153STATIC union node *
154list(nlflag)
155	int nlflag;
156{
157	union node *n1, *n2, *n3;
158	int tok;
159
160	checkkwd = 2;
161	if (nlflag == 0 && tokendlist[peektoken()])
162		return NULL;
163	n1 = NULL;
164	for (;;) {
165		n2 = andor();
166		tok = readtoken();
167		if (tok == TBACKGND) {
168			if (n2->type == NCMD || n2->type == NPIPE) {
169				n2->ncmd.backgnd = 1;
170			} else if (n2->type == NREDIR) {
171				n2->type = NBACKGND;
172			} else {
173				n3 = (union node *)stalloc(sizeof (struct nredir));
174				n3->type = NBACKGND;
175				n3->nredir.n = n2;
176				n3->nredir.redirect = NULL;
177				n2 = n3;
178			}
179		}
180		if (n1 == NULL) {
181			n1 = n2;
182		}
183		else {
184			n3 = (union node *)stalloc(sizeof (struct nbinary));
185			n3->type = NSEMI;
186			n3->nbinary.ch1 = n1;
187			n3->nbinary.ch2 = n2;
188			n1 = n3;
189		}
190		switch (tok) {
191		case TBACKGND:
192		case TSEMI:
193			tok = readtoken();
194			/* fall through */
195		case TNL:
196			if (tok == TNL) {
197				parseheredoc();
198				if (nlflag)
199					return n1;
200			} else {
201				tokpushback++;
202			}
203			checkkwd = 2;
204			if (tokendlist[peektoken()])
205				return n1;
206			break;
207		case TEOF:
208			if (heredoclist)
209				parseheredoc();
210			else
211				pungetc();		/* push back EOF on input */
212			return n1;
213		default:
214			if (nlflag)
215				synexpect(-1);
216			tokpushback++;
217			return n1;
218		}
219	}
220}
221
222
223
224STATIC union node *
225andor() {
226	union node *n1, *n2, *n3;
227	int t;
228
229	n1 = pipeline();
230	for (;;) {
231		if ((t = readtoken()) == TAND) {
232			t = NAND;
233		} else if (t == TOR) {
234			t = NOR;
235		} else {
236			tokpushback++;
237			return n1;
238		}
239		n2 = pipeline();
240		n3 = (union node *)stalloc(sizeof (struct nbinary));
241		n3->type = t;
242		n3->nbinary.ch1 = n1;
243		n3->nbinary.ch2 = n2;
244		n1 = n3;
245	}
246}
247
248
249
250STATIC union node *
251pipeline() {
252	union node *n1, *pipenode, *notnode;
253	struct nodelist *lp, *prev;
254	int negate = 0;
255
256	TRACE(("pipeline: entered\n"));
257	while (readtoken() == TNOT) {
258		TRACE(("pipeline: TNOT recognized\n"));
259		negate = !negate;
260	}
261	tokpushback++;
262	n1 = command();
263	if (readtoken() == TPIPE) {
264		pipenode = (union node *)stalloc(sizeof (struct npipe));
265		pipenode->type = NPIPE;
266		pipenode->npipe.backgnd = 0;
267		lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
268		pipenode->npipe.cmdlist = lp;
269		lp->n = n1;
270		do {
271			prev = lp;
272			lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
273			lp->n = command();
274			prev->next = lp;
275		} while (readtoken() == TPIPE);
276		lp->next = NULL;
277		n1 = pipenode;
278	}
279	tokpushback++;
280	if (negate) {
281		notnode = (union node *)stalloc(sizeof (struct nnot));
282		notnode->type = NNOT;
283		notnode->nnot.com = n1;
284		n1 = notnode;
285	}
286	return n1;
287}
288
289
290
291STATIC union node *
292command() {
293	union node *n1, *n2;
294	union node *ap, **app;
295	union node *cp, **cpp;
296	union node *redir, **rpp;
297	int t;
298
299	checkkwd = 2;
300	redir = NULL;
301	n1 = NULL;
302	rpp = &redir;
303	/* Check for redirection which may precede command */
304	while (readtoken() == TREDIR) {
305		*rpp = n2 = redirnode;
306		rpp = &n2->nfile.next;
307		parsefname();
308	}
309	tokpushback++;
310
311	switch (readtoken()) {
312	case TIF:
313		n1 = (union node *)stalloc(sizeof (struct nif));
314		n1->type = NIF;
315		n1->nif.test = list(0);
316		if (readtoken() != TTHEN)
317			synexpect(TTHEN);
318		n1->nif.ifpart = list(0);
319		n2 = n1;
320		while (readtoken() == TELIF) {
321			n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
322			n2 = n2->nif.elsepart;
323			n2->type = NIF;
324			n2->nif.test = list(0);
325			if (readtoken() != TTHEN)
326				synexpect(TTHEN);
327			n2->nif.ifpart = list(0);
328		}
329		if (lasttoken == TELSE)
330			n2->nif.elsepart = list(0);
331		else {
332			n2->nif.elsepart = NULL;
333			tokpushback++;
334		}
335		if (readtoken() != TFI)
336			synexpect(TFI);
337		checkkwd = 1;
338		break;
339	case TWHILE:
340	case TUNTIL: {
341		int got;
342		n1 = (union node *)stalloc(sizeof (struct nbinary));
343		n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
344		n1->nbinary.ch1 = list(0);
345		if ((got=readtoken()) != TDO) {
346TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
347			synexpect(TDO);
348		}
349		n1->nbinary.ch2 = list(0);
350		if (readtoken() != TDONE)
351			synexpect(TDONE);
352		checkkwd = 1;
353		break;
354	}
355	case TFOR:
356		if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
357			synerror("Bad for loop variable");
358		n1 = (union node *)stalloc(sizeof (struct nfor));
359		n1->type = NFOR;
360		n1->nfor.var = wordtext;
361		if (readtoken() == TWORD && ! quoteflag && equal(wordtext, "in")) {
362			app = &ap;
363			while (readtoken() == TWORD) {
364				n2 = (union node *)stalloc(sizeof (struct narg));
365				n2->type = NARG;
366				n2->narg.text = wordtext;
367				n2->narg.backquote = backquotelist;
368				*app = n2;
369				app = &n2->narg.next;
370			}
371			*app = NULL;
372			n1->nfor.args = ap;
373			if (lasttoken != TNL && lasttoken != TSEMI)
374				synexpect(-1);
375		} else {
376#ifndef GDB_HACK
377			static const char argvars[5] = {CTLVAR, VSNORMAL|VSQUOTE,
378								   '@', '=', '\0'};
379#endif
380			n2 = (union node *)stalloc(sizeof (struct narg));
381			n2->type = NARG;
382			n2->narg.text = (char *)argvars;
383			n2->narg.backquote = NULL;
384			n2->narg.next = NULL;
385			n1->nfor.args = n2;
386			/*
387			 * Newline or semicolon here is optional (but note
388			 * that the original Bourne shell only allowed NL).
389			 */
390			if (lasttoken != TNL && lasttoken != TSEMI)
391				tokpushback++;
392		}
393		checkkwd = 2;
394		if ((t = readtoken()) == TDO)
395			t = TDONE;
396		else if (t == TBEGIN)
397			t = TEND;
398		else
399			synexpect(-1);
400		n1->nfor.body = list(0);
401		if (readtoken() != t)
402			synexpect(t);
403		checkkwd = 1;
404		break;
405	case TCASE:
406		n1 = (union node *)stalloc(sizeof (struct ncase));
407		n1->type = NCASE;
408		if (readtoken() != TWORD)
409			synexpect(TWORD);
410		n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
411		n2->type = NARG;
412		n2->narg.text = wordtext;
413		n2->narg.backquote = backquotelist;
414		n2->narg.next = NULL;
415		while (readtoken() == TNL);
416		if (lasttoken != TWORD || ! equal(wordtext, "in"))
417			synerror("expecting \"in\"");
418		cpp = &n1->ncase.cases;
419		noaliases = 1;	/* turn off alias expansion */
420		checkkwd = 2, readtoken();
421		do {
422			*cpp = cp = (union node *)stalloc(sizeof (struct nclist));
423			cp->type = NCLIST;
424			app = &cp->nclist.pattern;
425			for (;;) {
426				*app = ap = (union node *)stalloc(sizeof (struct narg));
427				ap->type = NARG;
428				ap->narg.text = wordtext;
429				ap->narg.backquote = backquotelist;
430				if (checkkwd = 2, readtoken() != TPIPE)
431					break;
432				app = &ap->narg.next;
433				readtoken();
434			}
435			ap->narg.next = NULL;
436			if (lasttoken != TRP)
437				noaliases = 0, synexpect(TRP);
438			cp->nclist.body = list(0);
439
440			checkkwd = 2;
441			if ((t = readtoken()) != TESAC) {
442				if (t != TENDCASE)
443					noaliases = 0, synexpect(TENDCASE);
444				else
445					checkkwd = 2, readtoken();
446			}
447			cpp = &cp->nclist.next;
448		} while(lasttoken != TESAC);
449		noaliases = 0;	/* reset alias expansion */
450		*cpp = NULL;
451		checkkwd = 1;
452		break;
453	case TLP:
454		n1 = (union node *)stalloc(sizeof (struct nredir));
455		n1->type = NSUBSHELL;
456		n1->nredir.n = list(0);
457		n1->nredir.redirect = NULL;
458		if (readtoken() != TRP)
459			synexpect(TRP);
460		checkkwd = 1;
461		break;
462	case TBEGIN:
463		n1 = list(0);
464		if (readtoken() != TEND)
465			synexpect(TEND);
466		checkkwd = 1;
467		break;
468	/* Handle an empty command like other simple commands.  */
469	case TSEMI:
470		/*
471		 * An empty command before a ; doesn't make much sense, and
472		 * should certainly be disallowed in the case of `if ;'.
473		 */
474		if (!redir)
475			synexpect(-1);
476	case TAND:	/* XXX merge query! */
477	case TOR:	/* XXX merge query! */
478	case TNL:
479	case TEOF:
480	case TWORD:
481	case TRP:
482		tokpushback++;
483		return simplecmd(rpp, redir);
484	default:
485		synexpect(-1);
486	}
487
488	/* Now check for redirection which may follow command */
489	while (readtoken() == TREDIR) {
490		*rpp = n2 = redirnode;
491		rpp = &n2->nfile.next;
492		parsefname();
493	}
494	tokpushback++;
495	*rpp = NULL;
496	if (redir) {
497		if (n1->type != NSUBSHELL) {
498			n2 = (union node *)stalloc(sizeof (struct nredir));
499			n2->type = NREDIR;
500			n2->nredir.n = n1;
501			n1 = n2;
502		}
503		n1->nredir.redirect = redir;
504	}
505	return n1;
506}
507
508
509STATIC union node *
510simplecmd(rpp, redir)
511	union node **rpp, *redir;
512	{
513	union node *args, **app;
514	union node **orig_rpp = rpp;
515	union node *n = NULL;
516
517	/* If we don't have any redirections already, then we must reset */
518	/* rpp to be the address of the local redir variable.  */
519	if (redir == 0)
520		rpp = &redir;
521
522	args = NULL;
523	app = &args;
524	/*
525	 * We save the incoming value, because we need this for shell
526	 * functions.  There can not be a redirect or an argument between
527	 * the function name and the open parenthesis.
528	 */
529	orig_rpp = rpp;
530
531	for (;;) {
532		if (readtoken() == TWORD) {
533			n = (union node *)stalloc(sizeof (struct narg));
534			n->type = NARG;
535			n->narg.text = wordtext;
536			n->narg.backquote = backquotelist;
537			*app = n;
538			app = &n->narg.next;
539		} else if (lasttoken == TREDIR) {
540			*rpp = n = redirnode;
541			rpp = &n->nfile.next;
542			parsefname();	/* read name of redirection file */
543		} else if (lasttoken == TLP && app == &args->narg.next
544					    && rpp == orig_rpp) {
545			/* We have a function */
546			if (readtoken() != TRP)
547				synexpect(TRP);
548#ifdef notdef
549			if (! goodname(n->narg.text))
550				synerror("Bad function name");
551#endif
552			n->type = NDEFUN;
553			n->narg.next = command();
554			return n;
555		} else {
556			tokpushback++;
557			break;
558		}
559	}
560	*app = NULL;
561	*rpp = NULL;
562	n = (union node *)stalloc(sizeof (struct ncmd));
563	n->type = NCMD;
564	n->ncmd.backgnd = 0;
565	n->ncmd.args = args;
566	n->ncmd.redirect = redir;
567	return n;
568}
569
570STATIC union node *
571makename() {
572	union node *n;
573
574	n = (union node *)stalloc(sizeof (struct narg));
575	n->type = NARG;
576	n->narg.next = NULL;
577	n->narg.text = wordtext;
578	n->narg.backquote = backquotelist;
579	return n;
580}
581
582void fixredir(n, text, err)
583	union node *n;
584	const char *text;
585	int err;
586	{
587	TRACE(("Fix redir %s %d\n", text, err));
588	if (!err)
589		n->ndup.vname = NULL;
590
591	if (is_digit(text[0]) && text[1] == '\0')
592		n->ndup.dupfd = digit_val(text[0]);
593	else if (text[0] == '-' && text[1] == '\0')
594		n->ndup.dupfd = -1;
595	else {
596
597		if (err)
598			synerror("Bad fd number");
599		else
600			n->ndup.vname = makename();
601	}
602}
603
604
605STATIC void
606parsefname() {
607	union node *n = redirnode;
608
609	if (readtoken() != TWORD)
610		synexpect(-1);
611	if (n->type == NHERE) {
612		struct heredoc *here = heredoc;
613		struct heredoc *p;
614		int i;
615
616		if (quoteflag == 0)
617			n->type = NXHERE;
618		TRACE(("Here document %d\n", n->type));
619		if (here->striptabs) {
620			while (*wordtext == '\t')
621				wordtext++;
622		}
623		if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
624			synerror("Illegal eof marker for << redirection");
625		rmescapes(wordtext);
626		here->eofmark = wordtext;
627		here->next = NULL;
628		if (heredoclist == NULL)
629			heredoclist = here;
630		else {
631			for (p = heredoclist ; p->next ; p = p->next);
632			p->next = here;
633		}
634	} else if (n->type == NTOFD || n->type == NFROMFD) {
635		fixredir(n, wordtext, 0);
636	} else {
637		n->nfile.fname = makename();
638	}
639}
640
641
642/*
643 * Input any here documents.
644 */
645
646STATIC void
647parseheredoc() {
648	struct heredoc *here;
649	union node *n;
650
651	while (heredoclist) {
652		here = heredoclist;
653		heredoclist = here->next;
654		if (needprompt) {
655			setprompt(2);
656			needprompt = 0;
657		}
658		readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
659				here->eofmark, here->striptabs);
660		n = (union node *)stalloc(sizeof (struct narg));
661		n->narg.type = NARG;
662		n->narg.next = NULL;
663		n->narg.text = wordtext;
664		n->narg.backquote = backquotelist;
665		here->here->nhere.doc = n;
666	}
667}
668
669STATIC int
670peektoken() {
671	int t;
672
673	t = readtoken();
674	tokpushback++;
675	return (t);
676}
677
678STATIC int xxreadtoken();
679
680STATIC int
681readtoken() {
682	int t;
683	int savecheckkwd = checkkwd;
684	struct alias *ap;
685#ifdef DEBUG
686	int alreadyseen = tokpushback;
687#endif
688
689	top:
690	t = xxreadtoken();
691
692	if (checkkwd) {
693		/*
694		 * eat newlines
695		 */
696		if (checkkwd == 2) {
697			checkkwd = 0;
698			while (t == TNL) {
699				parseheredoc();
700				t = xxreadtoken();
701			}
702		} else
703			checkkwd = 0;
704		/*
705		 * check for keywords and aliases
706		 */
707		if (t == TWORD && !quoteflag)
708		{
709			register char * const *pp;
710
711			for (pp = (char **)parsekwd; *pp; pp++) {
712				if (**pp == *wordtext && equal(*pp, wordtext))
713				{
714					lasttoken = t = pp - parsekwd + KWDOFFSET;
715					TRACE(("keyword %s recognized\n", tokname[t]));
716					goto out;
717				}
718			}
719			if (noaliases == 0 &&
720			    (ap = lookupalias(wordtext, 1)) != NULL) {
721				pushstring(ap->val, strlen(ap->val), ap);
722				checkkwd = savecheckkwd;
723				goto top;
724			}
725		}
726out:
727		checkkwd = 0;
728	}
729#ifdef DEBUG
730	if (!alreadyseen)
731	    TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
732	else
733	    TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
734#endif
735	return (t);
736}
737
738
739/*
740 * Read the next input token.
741 * If the token is a word, we set backquotelist to the list of cmds in
742 *	backquotes.  We set quoteflag to true if any part of the word was
743 *	quoted.
744 * If the token is TREDIR, then we set redirnode to a structure containing
745 *	the redirection.
746 * In all cases, the variable startlinno is set to the number of the line
747 *	on which the token starts.
748 *
749 * [Change comment:  here documents and internal procedures]
750 * [Readtoken shouldn't have any arguments.  Perhaps we should make the
751 *  word parsing code into a separate routine.  In this case, readtoken
752 *  doesn't need to have any internal procedures, but parseword does.
753 *  We could also make parseoperator in essence the main routine, and
754 *  have parseword (readtoken1?) handle both words and redirection.]
755 */
756
757#define RETURN(token)	return lasttoken = token
758
759STATIC int
760xxreadtoken() {
761	register c;
762
763	if (tokpushback) {
764		tokpushback = 0;
765		return lasttoken;
766	}
767	if (needprompt) {
768		setprompt(2);
769		needprompt = 0;
770	}
771	startlinno = plinno;
772	for (;;) {	/* until token or start of word found */
773		c = pgetc_macro();
774		if (c == ' ' || c == '\t')
775			continue;		/* quick check for white space first */
776		switch (c) {
777		case ' ': case '\t':
778			continue;
779		case '#':
780			while ((c = pgetc()) != '\n' && c != PEOF);
781			pungetc();
782			continue;
783		case '\\':
784			if (pgetc() == '\n') {
785				startlinno = ++plinno;
786				if (doprompt)
787					setprompt(2);
788				else
789					setprompt(0);
790				continue;
791			}
792			pungetc();
793			goto breakloop;
794		case '\n':
795			plinno++;
796			needprompt = doprompt;
797			RETURN(TNL);
798		case PEOF:
799			RETURN(TEOF);
800		case '&':
801			if (pgetc() == '&')
802				RETURN(TAND);
803			pungetc();
804			RETURN(TBACKGND);
805		case '|':
806			if (pgetc() == '|')
807				RETURN(TOR);
808			pungetc();
809			RETURN(TPIPE);
810		case ';':
811			if (pgetc() == ';')
812				RETURN(TENDCASE);
813			pungetc();
814			RETURN(TSEMI);
815		case '(':
816			RETURN(TLP);
817		case ')':
818			RETURN(TRP);
819		default:
820			goto breakloop;
821		}
822	}
823breakloop:
824	return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
825#undef RETURN
826}
827
828
829
830/*
831 * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
832 * is not NULL, read a here document.  In the latter case, eofmark is the
833 * word which marks the end of the document and striptabs is true if
834 * leading tabs should be stripped from the document.  The argument firstc
835 * is the first character of the input token or document.
836 *
837 * Because C does not have internal subroutines, I have simulated them
838 * using goto's to implement the subroutine linkage.  The following macros
839 * will run code that appears at the end of readtoken1.
840 */
841
842#define CHECKEND()	{goto checkend; checkend_return:;}
843#define PARSEREDIR()	{goto parseredir; parseredir_return:;}
844#define PARSESUB()	{goto parsesub; parsesub_return:;}
845#define PARSEBACKQOLD()	{oldstyle = 1; goto parsebackq; parsebackq_oldreturn:;}
846#define PARSEBACKQNEW()	{oldstyle = 0; goto parsebackq; parsebackq_newreturn:;}
847#define	PARSEARITH()	{goto parsearith; parsearith_return:;}
848
849STATIC int
850readtoken1(firstc, syntax, eofmark, striptabs)
851	int firstc;
852	char const *syntax;
853	char *eofmark;
854	int striptabs;
855	{
856	int c = firstc;
857	char *out;
858	int len;
859	char line[EOFMARKLEN + 1];
860	struct nodelist *bqlist;
861	int quotef;
862	int dblquote;
863	int varnest;	/* levels of variables expansion */
864	int arinest;	/* levels of arithmetic expansion */
865	int parenlevel;	/* levels of parens in arithmetic */
866	int oldstyle;
867	char const *prevsyntax;	/* syntax before arithmetic */
868#if __GNUC__
869	/* Avoid longjmp clobbering */
870	(void) &out;
871	(void) &quotef;
872	(void) &dblquote;
873	(void) &varnest;
874	(void) &arinest;
875	(void) &parenlevel;
876	(void) &oldstyle;
877	(void) &prevsyntax;
878	(void) &syntax;
879#endif
880
881	startlinno = plinno;
882	dblquote = 0;
883	if (syntax == DQSYNTAX)
884		dblquote = 1;
885	quotef = 0;
886	bqlist = NULL;
887	varnest = 0;
888	arinest = 0;
889	parenlevel = 0;
890
891	STARTSTACKSTR(out);
892	loop: {	/* for each line, until end of word */
893#if ATTY
894		if (c == '\034' && doprompt
895		 && attyset() && ! equal(termval(), "emacs")) {
896			attyline();
897			if (syntax == BASESYNTAX)
898				return readtoken();
899			c = pgetc();
900			goto loop;
901		}
902#endif
903		CHECKEND();	/* set c to PEOF if at end of here document */
904		for (;;) {	/* until end of line or end of word */
905			CHECKSTRSPACE(3, out);	/* permit 3 calls to USTPUTC */
906			switch(syntax[c]) {
907			case CNL:	/* '\n' */
908				if (syntax == BASESYNTAX)
909					goto endword;	/* exit outer loop */
910				USTPUTC(c, out);
911				plinno++;
912				if (doprompt)
913					setprompt(2);
914				else
915					setprompt(0);
916				c = pgetc();
917				goto loop;		/* continue outer loop */
918			case CWORD:
919				USTPUTC(c, out);
920				break;
921			case CCTL:
922				if (eofmark == NULL || dblquote)
923					USTPUTC(CTLESC, out);
924				USTPUTC(c, out);
925				break;
926			case CBACK:	/* backslash */
927				c = pgetc();
928				if (c == PEOF) {
929					USTPUTC('\\', out);
930					pungetc();
931				} else if (c == '\n') {
932					if (doprompt)
933						setprompt(2);
934					else
935						setprompt(0);
936				} else {
937					if (dblquote && c != '\\' && c != '`' && c != '$'
938							 && (c != '"' || eofmark != NULL))
939						USTPUTC('\\', out);
940					if (SQSYNTAX[c] == CCTL)
941						USTPUTC(CTLESC, out);
942					USTPUTC(c, out);
943					quotef++;
944				}
945				break;
946			case CSQUOTE:
947				syntax = SQSYNTAX;
948				break;
949			case CDQUOTE:
950				syntax = DQSYNTAX;
951				dblquote = 1;
952				break;
953			case CENDQUOTE:
954				if (eofmark) {
955					USTPUTC(c, out);
956				} else {
957					if (arinest)
958						syntax = ARISYNTAX;
959					else
960						syntax = BASESYNTAX;
961					quotef++;
962					dblquote = 0;
963				}
964				break;
965			case CVAR:	/* '$' */
966				PARSESUB();		/* parse substitution */
967				break;
968			case CENDVAR:	/* '}' */
969				if (varnest > 0) {
970					varnest--;
971					USTPUTC(CTLENDVAR, out);
972				} else {
973					USTPUTC(c, out);
974				}
975				break;
976			case CLP:	/* '(' in arithmetic */
977				parenlevel++;
978				USTPUTC(c, out);
979				break;
980			case CRP:	/* ')' in arithmetic */
981				if (parenlevel > 0) {
982					USTPUTC(c, out);
983					--parenlevel;
984				} else {
985					if (pgetc() == ')') {
986						if (--arinest == 0) {
987							USTPUTC(CTLENDARI, out);
988							syntax = prevsyntax;
989						} else
990							USTPUTC(')', out);
991					} else {
992						/*
993						 * unbalanced parens
994						 *  (don't 2nd guess - no error)
995						 */
996						pungetc();
997						USTPUTC(')', out);
998					}
999				}
1000				break;
1001			case CBQUOTE:	/* '`' */
1002				PARSEBACKQOLD();
1003				break;
1004			case CEOF:
1005				goto endword;		/* exit outer loop */
1006			default:
1007				if (varnest == 0)
1008					goto endword;	/* exit outer loop */
1009				USTPUTC(c, out);
1010			}
1011			c = pgetc_macro();
1012		}
1013	}
1014endword:
1015	if (syntax == ARISYNTAX)
1016		synerror("Missing '))'");
1017	if (syntax != BASESYNTAX && ! parsebackquote && eofmark == NULL)
1018		synerror("Unterminated quoted string");
1019	if (varnest != 0) {
1020		startlinno = plinno;
1021		synerror("Missing '}'");
1022	}
1023	USTPUTC('\0', out);
1024	len = out - stackblock();
1025	out = stackblock();
1026	if (eofmark == NULL) {
1027		if ((c == '>' || c == '<')
1028		 && quotef == 0
1029		 && len <= 2
1030		 && (*out == '\0' || is_digit(*out))) {
1031			PARSEREDIR();
1032			return lasttoken = TREDIR;
1033		} else {
1034			pungetc();
1035		}
1036	}
1037	quoteflag = quotef;
1038	backquotelist = bqlist;
1039	grabstackblock(len);
1040	wordtext = out;
1041	return lasttoken = TWORD;
1042/* end of readtoken routine */
1043
1044
1045
1046/*
1047 * Check to see whether we are at the end of the here document.  When this
1048 * is called, c is set to the first character of the next input line.  If
1049 * we are at the end of the here document, this routine sets the c to PEOF.
1050 */
1051
1052checkend: {
1053	if (eofmark) {
1054		if (striptabs) {
1055			while (c == '\t')
1056				c = pgetc();
1057		}
1058		if (c == *eofmark) {
1059			if (pfgets(line, sizeof line) != NULL) {
1060				register char *p, *q;
1061
1062				p = line;
1063				for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1064				if (*p == '\n' && *q == '\0') {
1065					c = PEOF;
1066					plinno++;
1067					needprompt = doprompt;
1068				} else {
1069					pushstring(line, strlen(line), NULL);
1070				}
1071			}
1072		}
1073	}
1074	goto checkend_return;
1075}
1076
1077
1078/*
1079 * Parse a redirection operator.  The variable "out" points to a string
1080 * specifying the fd to be redirected.  The variable "c" contains the
1081 * first character of the redirection operator.
1082 */
1083
1084parseredir: {
1085	char fd = *out;
1086	union node *np;
1087
1088	np = (union node *)stalloc(sizeof (struct nfile));
1089	if (c == '>') {
1090		np->nfile.fd = 1;
1091		c = pgetc();
1092		if (c == '>')
1093			np->type = NAPPEND;
1094		else if (c == '&')
1095			np->type = NTOFD;
1096		else {
1097			np->type = NTO;
1098			pungetc();
1099		}
1100	} else {	/* c == '<' */
1101		np->nfile.fd = 0;
1102		c = pgetc();
1103		if (c == '<') {
1104			if (sizeof (struct nfile) != sizeof (struct nhere)) {
1105				np = (union node *)stalloc(sizeof (struct nhere));
1106				np->nfile.fd = 0;
1107			}
1108			np->type = NHERE;
1109			heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1110			heredoc->here = np;
1111			if ((c = pgetc()) == '-') {
1112				heredoc->striptabs = 1;
1113			} else {
1114				heredoc->striptabs = 0;
1115				pungetc();
1116			}
1117		} else if (c == '&')
1118			np->type = NFROMFD;
1119		else {
1120			np->type = NFROM;
1121			pungetc();
1122		}
1123	}
1124	if (fd != '\0')
1125		np->nfile.fd = digit_val(fd);
1126	redirnode = np;
1127	goto parseredir_return;
1128}
1129
1130
1131/*
1132 * Parse a substitution.  At this point, we have read the dollar sign
1133 * and nothing else.
1134 */
1135
1136parsesub: {
1137	int subtype;
1138	int typeloc;
1139	int flags;
1140	char *p;
1141#ifndef GDB_HACK
1142	static const char types[] = "}-+?=";
1143#endif
1144
1145	c = pgetc();
1146	if (c != '(' && c != '{' && !is_name(c) && !is_special(c)) {
1147		USTPUTC('$', out);
1148		pungetc();
1149	} else if (c == '(') {	/* $(command) or $((arith)) */
1150		if (pgetc() == '(') {
1151			PARSEARITH();
1152		} else {
1153			pungetc();
1154			PARSEBACKQNEW();
1155		}
1156	} else {
1157		USTPUTC(CTLVAR, out);
1158		typeloc = out - stackblock();
1159		USTPUTC(VSNORMAL, out);
1160		subtype = VSNORMAL;
1161		if (c == '{') {
1162			c = pgetc();
1163			if (c == '#') {
1164				if ((c = pgetc()) == '}')
1165					c = '#';
1166				else
1167					subtype = VSLENGTH;
1168			}
1169			else
1170				subtype = 0;
1171		}
1172		if (is_name(c)) {
1173			do {
1174				STPUTC(c, out);
1175				c = pgetc();
1176			} while (is_in_name(c));
1177		} else {
1178			if (! is_special(c))
1179badsub:				synerror("Bad substitution");
1180			USTPUTC(c, out);
1181			c = pgetc();
1182		}
1183		STPUTC('=', out);
1184		flags = 0;
1185		if (subtype == 0) {
1186			switch (c) {
1187			case ':':
1188				flags = VSNUL;
1189				c = pgetc();
1190				/*FALLTHROUGH*/
1191			default:
1192				p = strchr(types, c);
1193				if (p == NULL)
1194					goto badsub;
1195				subtype = p - types + VSNORMAL;
1196				break;
1197			case '%':
1198			case '#':
1199				{
1200					int cc = c;
1201					subtype = c == '#' ? VSTRIMLEFT :
1202							     VSTRIMRIGHT;
1203					c = pgetc();
1204					if (c == cc)
1205						subtype++;
1206					else
1207						pungetc();
1208					break;
1209				}
1210			}
1211		} else {
1212			pungetc();
1213		}
1214		if (dblquote || arinest)
1215			flags |= VSQUOTE;
1216		*(stackblock() + typeloc) = subtype | flags;
1217		if (subtype != VSNORMAL)
1218			varnest++;
1219	}
1220	goto parsesub_return;
1221}
1222
1223
1224/*
1225 * Called to parse command substitutions.  Newstyle is set if the command
1226 * is enclosed inside $(...); nlpp is a pointer to the head of the linked
1227 * list of commands (passed by reference), and savelen is the number of
1228 * characters on the top of the stack which must be preserved.
1229 */
1230
1231parsebackq: {
1232	struct nodelist **nlpp;
1233	int savepbq;
1234	union node *n;
1235	char *volatile str;
1236	struct jmploc jmploc;
1237	struct jmploc *volatile savehandler;
1238	int savelen;
1239
1240	savepbq = parsebackquote;
1241	if (setjmp(jmploc.loc)) {
1242		if (str)
1243			ckfree(str);
1244		parsebackquote = 0;
1245		handler = savehandler;
1246		longjmp(handler->loc, 1);
1247	}
1248	INTOFF;
1249	str = NULL;
1250	savelen = out - stackblock();
1251	if (savelen > 0) {
1252		str = ckmalloc(savelen);
1253		memcpy(str, stackblock(), savelen);
1254	}
1255	savehandler = handler;
1256	handler = &jmploc;
1257	INTON;
1258        if (oldstyle) {
1259                /* We must read until the closing backquote, giving special
1260                   treatment to some slashes, and then push the string and
1261                   reread it as input, interpreting it normally.  */
1262                register char *out;
1263                register c;
1264                int savelen;
1265                char *str;
1266
1267                STARTSTACKSTR(out);
1268                while ((c = pgetc ()) != '`') {
1269                       if (c == PEOF) {
1270                                startlinno = plinno;
1271                                synerror("EOF in backquote substitution");
1272                       }
1273                       if (c == '\\') {
1274                                c = pgetc ();
1275                                if (c != '\\' && c != '`' && c != '$'
1276                                    && (!dblquote || c != '"'))
1277                                        STPUTC('\\', out);
1278                       }
1279                       STPUTC(c, out);
1280                }
1281                STPUTC('\0', out);
1282                savelen = out - stackblock();
1283                if (savelen > 0) {
1284                        str = ckmalloc(savelen);
1285                        memcpy(str, stackblock(), savelen);
1286			setinputstring(str, 1);
1287                }
1288        }
1289	nlpp = &bqlist;
1290	while (*nlpp)
1291		nlpp = &(*nlpp)->next;
1292	*nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1293	(*nlpp)->next = NULL;
1294	parsebackquote = oldstyle;
1295	n = list(0);
1296        if (!oldstyle && (readtoken() != TRP))
1297                synexpect(TRP);
1298	(*nlpp)->n = n;
1299        /* Start reading from old file again.  */
1300        if (oldstyle)
1301                popfile();
1302	while (stackblocksize() <= savelen)
1303		growstackblock();
1304	STARTSTACKSTR(out);
1305	if (str) {
1306		memcpy(out, str, savelen);
1307		STADJUST(savelen, out);
1308		INTOFF;
1309		ckfree(str);
1310		str = NULL;
1311		INTON;
1312	}
1313	parsebackquote = savepbq;
1314	handler = savehandler;
1315	if (arinest || dblquote)
1316		USTPUTC(CTLBACKQ | CTLQUOTE, out);
1317	else
1318		USTPUTC(CTLBACKQ, out);
1319	if (oldstyle)
1320		goto parsebackq_oldreturn;
1321	else
1322		goto parsebackq_newreturn;
1323}
1324
1325/*
1326 * Parse an arithmetic expansion (indicate start of one and set state)
1327 */
1328parsearith: {
1329
1330	if (++arinest == 1) {
1331		prevsyntax = syntax;
1332		syntax = ARISYNTAX;
1333		USTPUTC(CTLARI, out);
1334	} else {
1335		/*
1336		 * we collapse embedded arithmetic expansion to
1337		 * parenthesis, which should be equivalent
1338		 */
1339		USTPUTC('(', out);
1340	}
1341	goto parsearith_return;
1342}
1343
1344} /* end of readtoken */
1345
1346
1347
1348#ifdef mkinit
1349RESET {
1350	tokpushback = 0;
1351	checkkwd = 0;
1352}
1353#endif
1354
1355/*
1356 * Returns true if the text contains nothing to expand (no dollar signs
1357 * or backquotes).
1358 */
1359
1360STATIC int
1361noexpand(text)
1362	char *text;
1363	{
1364	register char *p;
1365	register char c;
1366
1367	p = text;
1368	while ((c = *p++) != '\0') {
1369		if (c == CTLESC)
1370			p++;
1371		else if (BASESYNTAX[c] == CCTL)
1372			return 0;
1373	}
1374	return 1;
1375}
1376
1377
1378/*
1379 * Return true if the argument is a legal variable name (a letter or
1380 * underscore followed by zero or more letters, underscores, and digits).
1381 */
1382
1383int
1384goodname(name)
1385	char *name;
1386	{
1387	register char *p;
1388
1389	p = name;
1390	if (! is_name(*p))
1391		return 0;
1392	while (*++p) {
1393		if (! is_in_name(*p))
1394			return 0;
1395	}
1396	return 1;
1397}
1398
1399
1400/*
1401 * Called when an unexpected token is read during the parse.  The argument
1402 * is the token that is expected, or -1 if more than one type of token can
1403 * occur at this point.
1404 */
1405
1406STATIC void
1407synexpect(token)
1408	int token;
1409{
1410	char msg[64];
1411
1412	if (token >= 0) {
1413		fmtstr(msg, 64, "%s unexpected (expecting %s)",
1414			tokname[lasttoken], tokname[token]);
1415	} else {
1416		fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1417	}
1418	synerror(msg);
1419}
1420
1421
1422STATIC void
1423synerror(msg)
1424	char *msg;
1425	{
1426	if (commandname)
1427		outfmt(&errout, "%s: %d: ", commandname, startlinno);
1428	outfmt(&errout, "Syntax error: %s\n", msg);
1429	error((char *)NULL);
1430}
1431
1432STATIC void
1433setprompt(which)
1434	int which;
1435	{
1436	whichprompt = which;
1437
1438#ifndef NO_HISTORY
1439	if (!el)
1440#endif
1441		out2str(getprompt(NULL));
1442}
1443
1444/*
1445 * called by editline -- any expansions to the prompt
1446 *    should be added here.
1447 */
1448char *
1449getprompt(unused)
1450	void *unused;
1451	{
1452	switch (whichprompt) {
1453	case 0:
1454		return "";
1455	case 1:
1456		return ps1val();
1457	case 2:
1458		return ps2val();
1459	default:
1460		return "<internal prompt error>";
1461	}
1462}
1463