parser.c revision 214534 
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 * 4. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#ifndef lint
34#if 0
35static char sccsid[] = "@(#)parser.c	8.7 (Berkeley) 5/16/95";
36#endif
37#endif /* not lint */
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD: head/bin/sh/parser.c 214534 2010-10-29 21:20:56Z jilles $");
40
41#include <stdlib.h>
42#include <unistd.h>
43#include <stdio.h>
44
45#include "shell.h"
46#include "parser.h"
47#include "nodes.h"
48#include "expand.h"	/* defines rmescapes() */
49#include "syntax.h"
50#include "options.h"
51#include "input.h"
52#include "output.h"
53#include "var.h"
54#include "error.h"
55#include "memalloc.h"
56#include "mystring.h"
57#include "alias.h"
58#include "show.h"
59#include "eval.h"
60#include "exec.h"	/* to check for special builtins */
61#ifndef NO_HISTORY
62#include "myhistedit.h"
63#endif
64
65/*
66 * Shell command parser.
67 */
68
69#define	EOFMARKLEN	79
70#define	PROMPTLEN	128
71
72/* values returned by readtoken */
73#include "token.h"
74
75
76
77struct heredoc {
78	struct heredoc *next;	/* next here document in list */
79	union node *here;		/* redirection node */
80	char *eofmark;		/* string indicating end of input */
81	int striptabs;		/* if set, strip leading tabs */
82};
83
84struct parser_temp {
85	struct parser_temp *next;
86	void *data;
87};
88
89
90static struct heredoc *heredoclist;	/* list of here documents to read */
91static int doprompt;		/* if set, prompt the user */
92static int needprompt;		/* true if interactive and at start of line */
93static int lasttoken;		/* last token read */
94MKINIT int tokpushback;		/* last token pushed back */
95static char *wordtext;		/* text of last word returned by readtoken */
96MKINIT int checkkwd;            /* 1 == check for kwds, 2 == also eat newlines */
97static struct nodelist *backquotelist;
98static union node *redirnode;
99static struct heredoc *heredoc;
100static int quoteflag;		/* set if (part of) last token was quoted */
101static int startlinno;		/* line # where last token started */
102static int funclinno;		/* line # where the current function started */
103static struct parser_temp *parser_temp;
104
105/* XXX When 'noaliases' is set to one, no alias expansion takes place. */
106static int noaliases = 0;
107
108
109static union node *list(int, int);
110static union node *andor(void);
111static union node *pipeline(void);
112static union node *command(void);
113static union node *simplecmd(union node **, union node *);
114static union node *makename(void);
115static void parsefname(void);
116static void parseheredoc(void);
117static int peektoken(void);
118static int readtoken(void);
119static int xxreadtoken(void);
120static int readtoken1(int, char const *, char *, int);
121static int noexpand(char *);
122static void synexpect(int) __dead2;
123static void synerror(const char *) __dead2;
124static void setprompt(int);
125
126
127static void *
128parser_temp_alloc(size_t len)
129{
130	struct parser_temp *t;
131
132	INTOFF;
133	t = ckmalloc(sizeof(*t));
134	t->data = NULL;
135	t->next = parser_temp;
136	parser_temp = t;
137	t->data = ckmalloc(len);
138	INTON;
139	return t->data;
140}
141
142
143static void *
144parser_temp_realloc(void *ptr, size_t len)
145{
146	struct parser_temp *t;
147
148	INTOFF;
149	t = parser_temp;
150	if (ptr != t->data)
151		error("bug: parser_temp_realloc misused");
152	t->data = ckrealloc(t->data, len);
153	INTON;
154	return t->data;
155}
156
157
158static void
159parser_temp_free_upto(void *ptr)
160{
161	struct parser_temp *t;
162	int done = 0;
163
164	INTOFF;
165	while (parser_temp != NULL && !done) {
166		t = parser_temp;
167		parser_temp = t->next;
168		done = t->data == ptr;
169		ckfree(t->data);
170		ckfree(t);
171	}
172	INTON;
173	if (!done)
174		error("bug: parser_temp_free_upto misused");
175}
176
177
178static void
179parser_temp_free_all(void)
180{
181	struct parser_temp *t;
182
183	INTOFF;
184	while (parser_temp != NULL) {
185		t = parser_temp;
186		parser_temp = t->next;
187		ckfree(t->data);
188		ckfree(t);
189	}
190	INTON;
191}
192
193
194/*
195 * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
196 * valid parse tree indicating a blank line.)
197 */
198
199union node *
200parsecmd(int interact)
201{
202	int t;
203
204	/* This assumes the parser is not re-entered,
205	 * which could happen if we add command substitution on PS1/PS2.
206	 */
207	parser_temp_free_all();
208	heredoclist = NULL;
209
210	tokpushback = 0;
211	doprompt = interact;
212	if (doprompt)
213		setprompt(1);
214	else
215		setprompt(0);
216	needprompt = 0;
217	t = readtoken();
218	if (t == TEOF)
219		return NEOF;
220	if (t == TNL)
221		return NULL;
222	tokpushback++;
223	return list(1, 1);
224}
225
226
227static union node *
228list(int nlflag, int erflag)
229{
230	union node *n1, *n2, *n3;
231	int tok;
232
233	checkkwd = 2;
234	if (!nlflag && !erflag && tokendlist[peektoken()])
235		return NULL;
236	n1 = NULL;
237	for (;;) {
238		n2 = andor();
239		tok = readtoken();
240		if (tok == TBACKGND) {
241			if (n2->type == NCMD || n2->type == NPIPE) {
242				n2->ncmd.backgnd = 1;
243			} else if (n2->type == NREDIR) {
244				n2->type = NBACKGND;
245			} else {
246				n3 = (union node *)stalloc(sizeof (struct nredir));
247				n3->type = NBACKGND;
248				n3->nredir.n = n2;
249				n3->nredir.redirect = NULL;
250				n2 = n3;
251			}
252		}
253		if (n1 == NULL) {
254			n1 = n2;
255		}
256		else {
257			n3 = (union node *)stalloc(sizeof (struct nbinary));
258			n3->type = NSEMI;
259			n3->nbinary.ch1 = n1;
260			n3->nbinary.ch2 = n2;
261			n1 = n3;
262		}
263		switch (tok) {
264		case TBACKGND:
265		case TSEMI:
266			tok = readtoken();
267			/* FALLTHROUGH */
268		case TNL:
269			if (tok == TNL) {
270				parseheredoc();
271				if (nlflag)
272					return n1;
273			} else if (tok == TEOF && nlflag) {
274				parseheredoc();
275				return n1;
276			} else {
277				tokpushback++;
278			}
279			checkkwd = 2;
280			if (!nlflag && !erflag && tokendlist[peektoken()])
281				return n1;
282			break;
283		case TEOF:
284			if (heredoclist)
285				parseheredoc();
286			else
287				pungetc();		/* push back EOF on input */
288			return n1;
289		default:
290			if (nlflag || erflag)
291				synexpect(-1);
292			tokpushback++;
293			return n1;
294		}
295	}
296}
297
298
299
300static union node *
301andor(void)
302{
303	union node *n1, *n2, *n3;
304	int t;
305
306	n1 = pipeline();
307	for (;;) {
308		if ((t = readtoken()) == TAND) {
309			t = NAND;
310		} else if (t == TOR) {
311			t = NOR;
312		} else {
313			tokpushback++;
314			return n1;
315		}
316		n2 = pipeline();
317		n3 = (union node *)stalloc(sizeof (struct nbinary));
318		n3->type = t;
319		n3->nbinary.ch1 = n1;
320		n3->nbinary.ch2 = n2;
321		n1 = n3;
322	}
323}
324
325
326
327static union node *
328pipeline(void)
329{
330	union node *n1, *n2, *pipenode;
331	struct nodelist *lp, *prev;
332	int negate, t;
333
334	negate = 0;
335	checkkwd = 2;
336	TRACE(("pipeline: entered\n"));
337	while (readtoken() == TNOT)
338		negate = !negate;
339	tokpushback++;
340	n1 = command();
341	if (readtoken() == TPIPE) {
342		pipenode = (union node *)stalloc(sizeof (struct npipe));
343		pipenode->type = NPIPE;
344		pipenode->npipe.backgnd = 0;
345		lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
346		pipenode->npipe.cmdlist = lp;
347		lp->n = n1;
348		do {
349			prev = lp;
350			lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
351			checkkwd = 2;
352			t = readtoken();
353			tokpushback++;
354			if (t == TNOT)
355				lp->n = pipeline();
356			else
357				lp->n = command();
358			prev->next = lp;
359		} while (readtoken() == TPIPE);
360		lp->next = NULL;
361		n1 = pipenode;
362	}
363	tokpushback++;
364	if (negate) {
365		n2 = (union node *)stalloc(sizeof (struct nnot));
366		n2->type = NNOT;
367		n2->nnot.com = n1;
368		return n2;
369	} else
370		return n1;
371}
372
373
374
375static union node *
376command(void)
377{
378	union node *n1, *n2;
379	union node *ap, **app;
380	union node *cp, **cpp;
381	union node *redir, **rpp;
382	int t;
383
384	checkkwd = 2;
385	redir = NULL;
386	n1 = NULL;
387	rpp = &redir;
388
389	/* Check for redirection which may precede command */
390	while (readtoken() == TREDIR) {
391		*rpp = n2 = redirnode;
392		rpp = &n2->nfile.next;
393		parsefname();
394	}
395	tokpushback++;
396
397	switch (readtoken()) {
398	case TIF:
399		n1 = (union node *)stalloc(sizeof (struct nif));
400		n1->type = NIF;
401		if ((n1->nif.test = list(0, 0)) == NULL)
402			synexpect(-1);
403		if (readtoken() != TTHEN)
404			synexpect(TTHEN);
405		n1->nif.ifpart = list(0, 0);
406		n2 = n1;
407		while (readtoken() == TELIF) {
408			n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
409			n2 = n2->nif.elsepart;
410			n2->type = NIF;
411			if ((n2->nif.test = list(0, 0)) == NULL)
412				synexpect(-1);
413			if (readtoken() != TTHEN)
414				synexpect(TTHEN);
415			n2->nif.ifpart = list(0, 0);
416		}
417		if (lasttoken == TELSE)
418			n2->nif.elsepart = list(0, 0);
419		else {
420			n2->nif.elsepart = NULL;
421			tokpushback++;
422		}
423		if (readtoken() != TFI)
424			synexpect(TFI);
425		checkkwd = 1;
426		break;
427	case TWHILE:
428	case TUNTIL: {
429		int got;
430		n1 = (union node *)stalloc(sizeof (struct nbinary));
431		n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
432		if ((n1->nbinary.ch1 = list(0, 0)) == NULL)
433			synexpect(-1);
434		if ((got=readtoken()) != TDO) {
435TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
436			synexpect(TDO);
437		}
438		n1->nbinary.ch2 = list(0, 0);
439		if (readtoken() != TDONE)
440			synexpect(TDONE);
441		checkkwd = 1;
442		break;
443	}
444	case TFOR:
445		if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
446			synerror("Bad for loop variable");
447		n1 = (union node *)stalloc(sizeof (struct nfor));
448		n1->type = NFOR;
449		n1->nfor.var = wordtext;
450		while (readtoken() == TNL)
451			;
452		if (lasttoken == TWORD && ! quoteflag && equal(wordtext, "in")) {
453			app = &ap;
454			while (readtoken() == TWORD) {
455				n2 = (union node *)stalloc(sizeof (struct narg));
456				n2->type = NARG;
457				n2->narg.text = wordtext;
458				n2->narg.backquote = backquotelist;
459				*app = n2;
460				app = &n2->narg.next;
461			}
462			*app = NULL;
463			n1->nfor.args = ap;
464			if (lasttoken != TNL && lasttoken != TSEMI)
465				synexpect(-1);
466		} else {
467			static char argvars[5] = {
468				CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
469			};
470			n2 = (union node *)stalloc(sizeof (struct narg));
471			n2->type = NARG;
472			n2->narg.text = argvars;
473			n2->narg.backquote = NULL;
474			n2->narg.next = NULL;
475			n1->nfor.args = n2;
476			/*
477			 * Newline or semicolon here is optional (but note
478			 * that the original Bourne shell only allowed NL).
479			 */
480			if (lasttoken != TNL && lasttoken != TSEMI)
481				tokpushback++;
482		}
483		checkkwd = 2;
484		if ((t = readtoken()) == TDO)
485			t = TDONE;
486		else if (t == TBEGIN)
487			t = TEND;
488		else
489			synexpect(-1);
490		n1->nfor.body = list(0, 0);
491		if (readtoken() != t)
492			synexpect(t);
493		checkkwd = 1;
494		break;
495	case TCASE:
496		n1 = (union node *)stalloc(sizeof (struct ncase));
497		n1->type = NCASE;
498		if (readtoken() != TWORD)
499			synexpect(TWORD);
500		n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
501		n2->type = NARG;
502		n2->narg.text = wordtext;
503		n2->narg.backquote = backquotelist;
504		n2->narg.next = NULL;
505		while (readtoken() == TNL);
506		if (lasttoken != TWORD || ! equal(wordtext, "in"))
507			synerror("expecting \"in\"");
508		cpp = &n1->ncase.cases;
509		noaliases = 1;	/* turn off alias expansion */
510		checkkwd = 2, readtoken();
511		while (lasttoken != TESAC) {
512			*cpp = cp = (union node *)stalloc(sizeof (struct nclist));
513			cp->type = NCLIST;
514			app = &cp->nclist.pattern;
515			if (lasttoken == TLP)
516				readtoken();
517			for (;;) {
518				*app = ap = (union node *)stalloc(sizeof (struct narg));
519				ap->type = NARG;
520				ap->narg.text = wordtext;
521				ap->narg.backquote = backquotelist;
522				if (checkkwd = 2, readtoken() != TPIPE)
523					break;
524				app = &ap->narg.next;
525				readtoken();
526			}
527			ap->narg.next = NULL;
528			if (lasttoken != TRP)
529				noaliases = 0, synexpect(TRP);
530			cp->nclist.body = list(0, 0);
531
532			checkkwd = 2;
533			if ((t = readtoken()) != TESAC) {
534				if (t != TENDCASE)
535					noaliases = 0, synexpect(TENDCASE);
536				else
537					checkkwd = 2, readtoken();
538			}
539			cpp = &cp->nclist.next;
540		}
541		noaliases = 0;	/* reset alias expansion */
542		*cpp = NULL;
543		checkkwd = 1;
544		break;
545	case TLP:
546		n1 = (union node *)stalloc(sizeof (struct nredir));
547		n1->type = NSUBSHELL;
548		n1->nredir.n = list(0, 0);
549		n1->nredir.redirect = NULL;
550		if (readtoken() != TRP)
551			synexpect(TRP);
552		checkkwd = 1;
553		break;
554	case TBEGIN:
555		n1 = list(0, 0);
556		if (readtoken() != TEND)
557			synexpect(TEND);
558		checkkwd = 1;
559		break;
560	/* Handle an empty command like other simple commands.  */
561	case TBACKGND:
562	case TSEMI:
563	case TAND:
564	case TOR:
565		/*
566		 * An empty command before a ; doesn't make much sense, and
567		 * should certainly be disallowed in the case of `if ;'.
568		 */
569		if (!redir)
570			synexpect(-1);
571	case TNL:
572	case TEOF:
573	case TWORD:
574	case TRP:
575		tokpushback++;
576		n1 = simplecmd(rpp, redir);
577		return n1;
578	default:
579		synexpect(-1);
580	}
581
582	/* Now check for redirection which may follow command */
583	while (readtoken() == TREDIR) {
584		*rpp = n2 = redirnode;
585		rpp = &n2->nfile.next;
586		parsefname();
587	}
588	tokpushback++;
589	*rpp = NULL;
590	if (redir) {
591		if (n1->type != NSUBSHELL) {
592			n2 = (union node *)stalloc(sizeof (struct nredir));
593			n2->type = NREDIR;
594			n2->nredir.n = n1;
595			n1 = n2;
596		}
597		n1->nredir.redirect = redir;
598	}
599
600	return n1;
601}
602
603
604static union node *
605simplecmd(union node **rpp, union node *redir)
606{
607	union node *args, **app;
608	union node **orig_rpp = rpp;
609	union node *n = NULL;
610	int special;
611
612	/* If we don't have any redirections already, then we must reset */
613	/* rpp to be the address of the local redir variable.  */
614	if (redir == 0)
615		rpp = &redir;
616
617	args = NULL;
618	app = &args;
619	/*
620	 * We save the incoming value, because we need this for shell
621	 * functions.  There can not be a redirect or an argument between
622	 * the function name and the open parenthesis.
623	 */
624	orig_rpp = rpp;
625
626	for (;;) {
627		if (readtoken() == TWORD) {
628			n = (union node *)stalloc(sizeof (struct narg));
629			n->type = NARG;
630			n->narg.text = wordtext;
631			n->narg.backquote = backquotelist;
632			*app = n;
633			app = &n->narg.next;
634		} else if (lasttoken == TREDIR) {
635			*rpp = n = redirnode;
636			rpp = &n->nfile.next;
637			parsefname();	/* read name of redirection file */
638		} else if (lasttoken == TLP && app == &args->narg.next
639					    && rpp == orig_rpp) {
640			/* We have a function */
641			if (readtoken() != TRP)
642				synexpect(TRP);
643			funclinno = plinno;
644			/*
645			 * - Require plain text.
646			 * - Functions with '/' cannot be called.
647			 * - Reject name=().
648			 * - Reject ksh extended glob patterns.
649			 */
650			if (!noexpand(n->narg.text) || quoteflag ||
651			    strchr(n->narg.text, '/') ||
652			    strchr("!%*+-=?@}~",
653				n->narg.text[strlen(n->narg.text) - 1]))
654				synerror("Bad function name");
655			rmescapes(n->narg.text);
656			if (find_builtin(n->narg.text, &special) >= 0 &&
657			    special)
658				synerror("Cannot override a special builtin with a function");
659			n->type = NDEFUN;
660			n->narg.next = command();
661			funclinno = 0;
662			return n;
663		} else {
664			tokpushback++;
665			break;
666		}
667	}
668	*app = NULL;
669	*rpp = NULL;
670	n = (union node *)stalloc(sizeof (struct ncmd));
671	n->type = NCMD;
672	n->ncmd.backgnd = 0;
673	n->ncmd.args = args;
674	n->ncmd.redirect = redir;
675	return n;
676}
677
678static union node *
679makename(void)
680{
681	union node *n;
682
683	n = (union node *)stalloc(sizeof (struct narg));
684	n->type = NARG;
685	n->narg.next = NULL;
686	n->narg.text = wordtext;
687	n->narg.backquote = backquotelist;
688	return n;
689}
690
691void
692fixredir(union node *n, const char *text, int err)
693{
694	TRACE(("Fix redir %s %d\n", text, err));
695	if (!err)
696		n->ndup.vname = NULL;
697
698	if (is_digit(text[0]) && text[1] == '\0')
699		n->ndup.dupfd = digit_val(text[0]);
700	else if (text[0] == '-' && text[1] == '\0')
701		n->ndup.dupfd = -1;
702	else {
703
704		if (err)
705			synerror("Bad fd number");
706		else
707			n->ndup.vname = makename();
708	}
709}
710
711
712static void
713parsefname(void)
714{
715	union node *n = redirnode;
716
717	if (readtoken() != TWORD)
718		synexpect(-1);
719	if (n->type == NHERE) {
720		struct heredoc *here = heredoc;
721		struct heredoc *p;
722		int i;
723
724		if (quoteflag == 0)
725			n->type = NXHERE;
726		TRACE(("Here document %d\n", n->type));
727		if (here->striptabs) {
728			while (*wordtext == '\t')
729				wordtext++;
730		}
731		if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
732			synerror("Illegal eof marker for << redirection");
733		rmescapes(wordtext);
734		here->eofmark = wordtext;
735		here->next = NULL;
736		if (heredoclist == NULL)
737			heredoclist = here;
738		else {
739			for (p = heredoclist ; p->next ; p = p->next);
740			p->next = here;
741		}
742	} else if (n->type == NTOFD || n->type == NFROMFD) {
743		fixredir(n, wordtext, 0);
744	} else {
745		n->nfile.fname = makename();
746	}
747}
748
749
750/*
751 * Input any here documents.
752 */
753
754static void
755parseheredoc(void)
756{
757	struct heredoc *here;
758	union node *n;
759
760	while (heredoclist) {
761		here = heredoclist;
762		heredoclist = here->next;
763		if (needprompt) {
764			setprompt(2);
765			needprompt = 0;
766		}
767		readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
768				here->eofmark, here->striptabs);
769		n = (union node *)stalloc(sizeof (struct narg));
770		n->narg.type = NARG;
771		n->narg.next = NULL;
772		n->narg.text = wordtext;
773		n->narg.backquote = backquotelist;
774		here->here->nhere.doc = n;
775	}
776}
777
778static int
779peektoken(void)
780{
781	int t;
782
783	t = readtoken();
784	tokpushback++;
785	return (t);
786}
787
788static int
789readtoken(void)
790{
791	int t;
792	int savecheckkwd = checkkwd;
793	struct alias *ap;
794#ifdef DEBUG
795	int alreadyseen = tokpushback;
796#endif
797
798	top:
799	t = xxreadtoken();
800
801	if (checkkwd) {
802		/*
803		 * eat newlines
804		 */
805		if (checkkwd == 2) {
806			checkkwd = 0;
807			while (t == TNL) {
808				parseheredoc();
809				t = xxreadtoken();
810			}
811		} else
812			checkkwd = 0;
813		/*
814		 * check for keywords and aliases
815		 */
816		if (t == TWORD && !quoteflag)
817		{
818			const char * const *pp;
819
820			for (pp = parsekwd; *pp; pp++) {
821				if (**pp == *wordtext && equal(*pp, wordtext))
822				{
823					lasttoken = t = pp - parsekwd + KWDOFFSET;
824					TRACE(("keyword %s recognized\n", tokname[t]));
825					goto out;
826				}
827			}
828			if (noaliases == 0 &&
829			    (ap = lookupalias(wordtext, 1)) != NULL) {
830				pushstring(ap->val, strlen(ap->val), ap);
831				checkkwd = savecheckkwd;
832				goto top;
833			}
834		}
835out:
836		checkkwd = (t == TNOT) ? savecheckkwd : 0;
837	}
838#ifdef DEBUG
839	if (!alreadyseen)
840	    TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
841	else
842	    TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
843#endif
844	return (t);
845}
846
847
848/*
849 * Read the next input token.
850 * If the token is a word, we set backquotelist to the list of cmds in
851 *	backquotes.  We set quoteflag to true if any part of the word was
852 *	quoted.
853 * If the token is TREDIR, then we set redirnode to a structure containing
854 *	the redirection.
855 * In all cases, the variable startlinno is set to the number of the line
856 *	on which the token starts.
857 *
858 * [Change comment:  here documents and internal procedures]
859 * [Readtoken shouldn't have any arguments.  Perhaps we should make the
860 *  word parsing code into a separate routine.  In this case, readtoken
861 *  doesn't need to have any internal procedures, but parseword does.
862 *  We could also make parseoperator in essence the main routine, and
863 *  have parseword (readtoken1?) handle both words and redirection.]
864 */
865
866#define RETURN(token)	return lasttoken = token
867
868static int
869xxreadtoken(void)
870{
871	int c;
872
873	if (tokpushback) {
874		tokpushback = 0;
875		return lasttoken;
876	}
877	if (needprompt) {
878		setprompt(2);
879		needprompt = 0;
880	}
881	startlinno = plinno;
882	for (;;) {	/* until token or start of word found */
883		c = pgetc_macro();
884		if (c == ' ' || c == '\t')
885			continue;		/* quick check for white space first */
886		switch (c) {
887		case ' ': case '\t':
888			continue;
889		case '#':
890			while ((c = pgetc()) != '\n' && c != PEOF);
891			pungetc();
892			continue;
893		case '\\':
894			if (pgetc() == '\n') {
895				startlinno = ++plinno;
896				if (doprompt)
897					setprompt(2);
898				else
899					setprompt(0);
900				continue;
901			}
902			pungetc();
903			goto breakloop;
904		case '\n':
905			plinno++;
906			needprompt = doprompt;
907			RETURN(TNL);
908		case PEOF:
909			RETURN(TEOF);
910		case '&':
911			if (pgetc() == '&')
912				RETURN(TAND);
913			pungetc();
914			RETURN(TBACKGND);
915		case '|':
916			if (pgetc() == '|')
917				RETURN(TOR);
918			pungetc();
919			RETURN(TPIPE);
920		case ';':
921			if (pgetc() == ';')
922				RETURN(TENDCASE);
923			pungetc();
924			RETURN(TSEMI);
925		case '(':
926			RETURN(TLP);
927		case ')':
928			RETURN(TRP);
929		default:
930			goto breakloop;
931		}
932	}
933breakloop:
934	return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
935#undef RETURN
936}
937
938
939#define MAXNEST_static 8
940struct tokenstate
941{
942	const char *syntax; /* *SYNTAX */
943	int parenlevel; /* levels of parentheses in arithmetic */
944	enum tokenstate_category
945	{
946		TSTATE_TOP,
947		TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
948		TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
949		TSTATE_ARITH
950	} category;
951};
952
953
954/*
955 * Called to parse command substitutions.
956 */
957
958static char *
959parsebackq(char *out, struct nodelist **pbqlist,
960		int oldstyle, int dblquote, int quoted)
961{
962	struct nodelist **nlpp;
963	union node *n;
964	char *volatile str;
965	struct jmploc jmploc;
966	struct jmploc *const savehandler = handler;
967	int savelen;
968	int saveprompt;
969	const int bq_startlinno = plinno;
970	char *volatile ostr = NULL;
971	struct parsefile *const savetopfile = getcurrentfile();
972	struct heredoc *const saveheredoclist = heredoclist;
973	struct heredoc *here;
974
975	str = NULL;
976	if (setjmp(jmploc.loc)) {
977		popfilesupto(savetopfile);
978		if (str)
979			ckfree(str);
980		if (ostr)
981			ckfree(ostr);
982		heredoclist = saveheredoclist;
983		handler = savehandler;
984		if (exception == EXERROR) {
985			startlinno = bq_startlinno;
986			synerror("Error in command substitution");
987		}
988		longjmp(handler->loc, 1);
989	}
990	INTOFF;
991	savelen = out - stackblock();
992	if (savelen > 0) {
993		str = ckmalloc(savelen);
994		memcpy(str, stackblock(), savelen);
995	}
996	handler = &jmploc;
997	heredoclist = NULL;
998	INTON;
999        if (oldstyle) {
1000                /* We must read until the closing backquote, giving special
1001                   treatment to some slashes, and then push the string and
1002                   reread it as input, interpreting it normally.  */
1003                char *oout;
1004                int c;
1005                int olen;
1006
1007
1008                STARTSTACKSTR(oout);
1009		for (;;) {
1010			if (needprompt) {
1011				setprompt(2);
1012				needprompt = 0;
1013			}
1014			switch (c = pgetc()) {
1015			case '`':
1016				goto done;
1017
1018			case '\\':
1019                                if ((c = pgetc()) == '\n') {
1020					plinno++;
1021					if (doprompt)
1022						setprompt(2);
1023					else
1024						setprompt(0);
1025					/*
1026					 * If eating a newline, avoid putting
1027					 * the newline into the new character
1028					 * stream (via the STPUTC after the
1029					 * switch).
1030					 */
1031					continue;
1032				}
1033                                if (c != '\\' && c != '`' && c != '$'
1034                                    && (!dblquote || c != '"'))
1035                                        STPUTC('\\', oout);
1036				break;
1037
1038			case '\n':
1039				plinno++;
1040				needprompt = doprompt;
1041				break;
1042
1043			case PEOF:
1044			        startlinno = plinno;
1045				synerror("EOF in backquote substitution");
1046 				break;
1047
1048			default:
1049				break;
1050			}
1051			STPUTC(c, oout);
1052                }
1053done:
1054                STPUTC('\0', oout);
1055                olen = oout - stackblock();
1056		INTOFF;
1057		ostr = ckmalloc(olen);
1058		memcpy(ostr, stackblock(), olen);
1059		setinputstring(ostr, 1);
1060		INTON;
1061        }
1062	nlpp = pbqlist;
1063	while (*nlpp)
1064		nlpp = &(*nlpp)->next;
1065	*nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1066	(*nlpp)->next = NULL;
1067
1068	if (oldstyle) {
1069		saveprompt = doprompt;
1070		doprompt = 0;
1071	}
1072
1073	n = list(0, oldstyle);
1074
1075	if (oldstyle)
1076		doprompt = saveprompt;
1077	else {
1078		if (readtoken() != TRP)
1079			synexpect(TRP);
1080	}
1081
1082	(*nlpp)->n = n;
1083        if (oldstyle) {
1084		/*
1085		 * Start reading from old file again, ignoring any pushed back
1086		 * tokens left from the backquote parsing
1087		 */
1088                popfile();
1089		tokpushback = 0;
1090	}
1091	while (stackblocksize() <= savelen)
1092		growstackblock();
1093	STARTSTACKSTR(out);
1094	INTOFF;
1095	if (str) {
1096		memcpy(out, str, savelen);
1097		STADJUST(savelen, out);
1098		ckfree(str);
1099		str = NULL;
1100	}
1101	if (ostr) {
1102		ckfree(ostr);
1103		ostr = NULL;
1104	}
1105	here = saveheredoclist;
1106	if (here != NULL) {
1107		while (here->next != NULL)
1108			here = here->next;
1109		here->next = heredoclist;
1110		heredoclist = saveheredoclist;
1111	}
1112	handler = savehandler;
1113	INTON;
1114	if (quoted)
1115		USTPUTC(CTLBACKQ | CTLQUOTE, out);
1116	else
1117		USTPUTC(CTLBACKQ, out);
1118	return out;
1119}
1120
1121
1122/*
1123 * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
1124 * is not NULL, read a here document.  In the latter case, eofmark is the
1125 * word which marks the end of the document and striptabs is true if
1126 * leading tabs should be stripped from the document.  The argument firstc
1127 * is the first character of the input token or document.
1128 *
1129 * Because C does not have internal subroutines, I have simulated them
1130 * using goto's to implement the subroutine linkage.  The following macros
1131 * will run code that appears at the end of readtoken1.
1132 */
1133
1134#define CHECKEND()	{goto checkend; checkend_return:;}
1135#define PARSEREDIR()	{goto parseredir; parseredir_return:;}
1136#define PARSESUB()	{goto parsesub; parsesub_return:;}
1137#define	PARSEARITH()	{goto parsearith; parsearith_return:;}
1138
1139static int
1140readtoken1(int firstc, char const *initialsyntax, char *eofmark, int striptabs)
1141{
1142	int c = firstc;
1143	char *out;
1144	int len;
1145	char line[EOFMARKLEN + 1];
1146	struct nodelist *bqlist;
1147	int quotef;
1148	int newvarnest;
1149	int level;
1150	int synentry;
1151	struct tokenstate state_static[MAXNEST_static];
1152	int maxnest = MAXNEST_static;
1153	struct tokenstate *state = state_static;
1154
1155	startlinno = plinno;
1156	quotef = 0;
1157	bqlist = NULL;
1158	newvarnest = 0;
1159	level = 0;
1160	state[level].syntax = initialsyntax;
1161	state[level].parenlevel = 0;
1162	state[level].category = TSTATE_TOP;
1163
1164	STARTSTACKSTR(out);
1165	loop: {	/* for each line, until end of word */
1166		CHECKEND();	/* set c to PEOF if at end of here document */
1167		for (;;) {	/* until end of line or end of word */
1168			CHECKSTRSPACE(4, out);	/* permit 4 calls to USTPUTC */
1169
1170			synentry = state[level].syntax[c];
1171
1172			switch(synentry) {
1173			case CNL:	/* '\n' */
1174				if (state[level].syntax == BASESYNTAX)
1175					goto endword;	/* exit outer loop */
1176				USTPUTC(c, out);
1177				plinno++;
1178				if (doprompt)
1179					setprompt(2);
1180				else
1181					setprompt(0);
1182				c = pgetc();
1183				goto loop;		/* continue outer loop */
1184			case CWORD:
1185				USTPUTC(c, out);
1186				break;
1187			case CCTL:
1188				if (eofmark == NULL || initialsyntax != SQSYNTAX)
1189					USTPUTC(CTLESC, out);
1190				USTPUTC(c, out);
1191				break;
1192			case CBACK:	/* backslash */
1193				c = pgetc();
1194				if (c == PEOF) {
1195					USTPUTC('\\', out);
1196					pungetc();
1197				} else if (c == '\n') {
1198					plinno++;
1199					if (doprompt)
1200						setprompt(2);
1201					else
1202						setprompt(0);
1203				} else {
1204					if (state[level].syntax == DQSYNTAX &&
1205					    c != '\\' && c != '`' && c != '$' &&
1206					    (c != '"' || (eofmark != NULL &&
1207						newvarnest == 0)) &&
1208					    (c != '}' || state[level].category != TSTATE_VAR_OLD))
1209						USTPUTC('\\', out);
1210					if ((eofmark == NULL ||
1211					    newvarnest > 0) &&
1212					    state[level].syntax == BASESYNTAX)
1213						USTPUTC(CTLQUOTEMARK, out);
1214					if (SQSYNTAX[c] == CCTL)
1215						USTPUTC(CTLESC, out);
1216					USTPUTC(c, out);
1217					if ((eofmark == NULL ||
1218					    newvarnest > 0) &&
1219					    state[level].syntax == BASESYNTAX &&
1220					    state[level].category == TSTATE_VAR_OLD)
1221						USTPUTC(CTLQUOTEEND, out);
1222					quotef++;
1223				}
1224				break;
1225			case CSQUOTE:
1226				USTPUTC(CTLQUOTEMARK, out);
1227				state[level].syntax = SQSYNTAX;
1228				break;
1229			case CDQUOTE:
1230				USTPUTC(CTLQUOTEMARK, out);
1231				state[level].syntax = DQSYNTAX;
1232				break;
1233			case CENDQUOTE:
1234				if (eofmark != NULL && newvarnest == 0)
1235					USTPUTC(c, out);
1236				else {
1237					if (state[level].category == TSTATE_VAR_OLD)
1238						USTPUTC(CTLQUOTEEND, out);
1239					state[level].syntax = BASESYNTAX;
1240					quotef++;
1241				}
1242				break;
1243			case CVAR:	/* '$' */
1244				PARSESUB();		/* parse substitution */
1245				break;
1246			case CENDVAR:	/* '}' */
1247				if (level > 0 &&
1248				    ((state[level].category == TSTATE_VAR_OLD &&
1249				      state[level].syntax ==
1250				      state[level - 1].syntax) ||
1251				    (state[level].category == TSTATE_VAR_NEW &&
1252				     state[level].syntax == BASESYNTAX))) {
1253					if (state[level].category == TSTATE_VAR_NEW)
1254						newvarnest--;
1255					level--;
1256					USTPUTC(CTLENDVAR, out);
1257				} else {
1258					USTPUTC(c, out);
1259				}
1260				break;
1261			case CLP:	/* '(' in arithmetic */
1262				state[level].parenlevel++;
1263				USTPUTC(c, out);
1264				break;
1265			case CRP:	/* ')' in arithmetic */
1266				if (state[level].parenlevel > 0) {
1267					USTPUTC(c, out);
1268					--state[level].parenlevel;
1269				} else {
1270					if (pgetc() == ')') {
1271						if (level > 0 &&
1272						    state[level].category == TSTATE_ARITH) {
1273							level--;
1274							USTPUTC(CTLENDARI, out);
1275						} else
1276							USTPUTC(')', out);
1277					} else {
1278						/*
1279						 * unbalanced parens
1280						 *  (don't 2nd guess - no error)
1281						 */
1282						pungetc();
1283						USTPUTC(')', out);
1284					}
1285				}
1286				break;
1287			case CBQUOTE:	/* '`' */
1288				out = parsebackq(out, &bqlist, 1,
1289				    state[level].syntax == DQSYNTAX &&
1290				    (eofmark == NULL || newvarnest > 0),
1291				    state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
1292				break;
1293			case CEOF:
1294				goto endword;		/* exit outer loop */
1295			case CIGN:
1296				break;
1297			default:
1298				if (level == 0)
1299					goto endword;	/* exit outer loop */
1300				USTPUTC(c, out);
1301			}
1302			c = pgetc_macro();
1303		}
1304	}
1305endword:
1306	if (state[level].syntax == ARISYNTAX)
1307		synerror("Missing '))'");
1308	if (state[level].syntax != BASESYNTAX && eofmark == NULL)
1309		synerror("Unterminated quoted string");
1310	if (state[level].category == TSTATE_VAR_OLD ||
1311	    state[level].category == TSTATE_VAR_NEW) {
1312		startlinno = plinno;
1313		synerror("Missing '}'");
1314	}
1315	if (state != state_static)
1316		parser_temp_free_upto(state);
1317	USTPUTC('\0', out);
1318	len = out - stackblock();
1319	out = stackblock();
1320	if (eofmark == NULL) {
1321		if ((c == '>' || c == '<')
1322		 && quotef == 0
1323		 && len <= 2
1324		 && (*out == '\0' || is_digit(*out))) {
1325			PARSEREDIR();
1326			return lasttoken = TREDIR;
1327		} else {
1328			pungetc();
1329		}
1330	}
1331	quoteflag = quotef;
1332	backquotelist = bqlist;
1333	grabstackblock(len);
1334	wordtext = out;
1335	return lasttoken = TWORD;
1336/* end of readtoken routine */
1337
1338
1339/*
1340 * Check to see whether we are at the end of the here document.  When this
1341 * is called, c is set to the first character of the next input line.  If
1342 * we are at the end of the here document, this routine sets the c to PEOF.
1343 */
1344
1345checkend: {
1346	if (eofmark) {
1347		if (striptabs) {
1348			while (c == '\t')
1349				c = pgetc();
1350		}
1351		if (c == *eofmark) {
1352			if (pfgets(line, sizeof line) != NULL) {
1353				char *p, *q;
1354
1355				p = line;
1356				for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1357				if (*p == '\n' && *q == '\0') {
1358					c = PEOF;
1359					plinno++;
1360					needprompt = doprompt;
1361				} else {
1362					pushstring(line, strlen(line), NULL);
1363				}
1364			}
1365		}
1366	}
1367	goto checkend_return;
1368}
1369
1370
1371/*
1372 * Parse a redirection operator.  The variable "out" points to a string
1373 * specifying the fd to be redirected.  The variable "c" contains the
1374 * first character of the redirection operator.
1375 */
1376
1377parseredir: {
1378	char fd = *out;
1379	union node *np;
1380
1381	np = (union node *)stalloc(sizeof (struct nfile));
1382	if (c == '>') {
1383		np->nfile.fd = 1;
1384		c = pgetc();
1385		if (c == '>')
1386			np->type = NAPPEND;
1387		else if (c == '&')
1388			np->type = NTOFD;
1389		else if (c == '|')
1390			np->type = NCLOBBER;
1391		else {
1392			np->type = NTO;
1393			pungetc();
1394		}
1395	} else {	/* c == '<' */
1396		np->nfile.fd = 0;
1397		c = pgetc();
1398		if (c == '<') {
1399			if (sizeof (struct nfile) != sizeof (struct nhere)) {
1400				np = (union node *)stalloc(sizeof (struct nhere));
1401				np->nfile.fd = 0;
1402			}
1403			np->type = NHERE;
1404			heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1405			heredoc->here = np;
1406			if ((c = pgetc()) == '-') {
1407				heredoc->striptabs = 1;
1408			} else {
1409				heredoc->striptabs = 0;
1410				pungetc();
1411			}
1412		} else if (c == '&')
1413			np->type = NFROMFD;
1414		else if (c == '>')
1415			np->type = NFROMTO;
1416		else {
1417			np->type = NFROM;
1418			pungetc();
1419		}
1420	}
1421	if (fd != '\0')
1422		np->nfile.fd = digit_val(fd);
1423	redirnode = np;
1424	goto parseredir_return;
1425}
1426
1427
1428/*
1429 * Parse a substitution.  At this point, we have read the dollar sign
1430 * and nothing else.
1431 */
1432
1433parsesub: {
1434	char buf[10];
1435	int subtype;
1436	int typeloc;
1437	int flags;
1438	char *p;
1439	static const char types[] = "}-+?=";
1440	int bracketed_name = 0; /* used to handle ${[0-9]*} variables */
1441	int i;
1442	int linno;
1443	int length;
1444
1445	c = pgetc();
1446	if (c != '(' && c != '{' && (is_eof(c) || !is_name(c)) &&
1447	    !is_special(c)) {
1448		USTPUTC('$', out);
1449		pungetc();
1450	} else if (c == '(') {	/* $(command) or $((arith)) */
1451		if (pgetc() == '(') {
1452			PARSEARITH();
1453		} else {
1454			pungetc();
1455			out = parsebackq(out, &bqlist, 0,
1456			    state[level].syntax == DQSYNTAX &&
1457			    (eofmark == NULL || newvarnest > 0),
1458			    state[level].syntax == DQSYNTAX ||
1459			    state[level].syntax == ARISYNTAX);
1460		}
1461	} else {
1462		USTPUTC(CTLVAR, out);
1463		typeloc = out - stackblock();
1464		USTPUTC(VSNORMAL, out);
1465		subtype = VSNORMAL;
1466		flags = 0;
1467		if (c == '{') {
1468			bracketed_name = 1;
1469			c = pgetc();
1470			if (c == '#') {
1471				if ((c = pgetc()) == '}')
1472					c = '#';
1473				else
1474					subtype = VSLENGTH;
1475			}
1476			else
1477				subtype = 0;
1478		}
1479		if (!is_eof(c) && is_name(c)) {
1480			length = 0;
1481			do {
1482				STPUTC(c, out);
1483				c = pgetc();
1484				length++;
1485			} while (!is_eof(c) && is_in_name(c));
1486			if (length == 6 &&
1487			    strncmp(out - length, "LINENO", length) == 0) {
1488				/* Replace the variable name with the
1489				 * current line number. */
1490				linno = plinno;
1491				if (funclinno != 0)
1492					linno -= funclinno - 1;
1493				snprintf(buf, sizeof(buf), "%d", linno);
1494				STADJUST(-6, out);
1495				for (i = 0; buf[i] != '\0'; i++)
1496					STPUTC(buf[i], out);
1497				flags |= VSLINENO;
1498			}
1499		} else if (is_digit(c)) {
1500			if (bracketed_name) {
1501				do {
1502					STPUTC(c, out);
1503					c = pgetc();
1504				} while (is_digit(c));
1505			} else {
1506				STPUTC(c, out);
1507				c = pgetc();
1508			}
1509		} else {
1510			if (! is_special(c)) {
1511				subtype = VSERROR;
1512				if (c == '}')
1513					pungetc();
1514				else if (c == '\n' || c == PEOF)
1515					synerror("Unexpected end of line in substitution");
1516				else
1517					USTPUTC(c, out);
1518			} else {
1519				USTPUTC(c, out);
1520				c = pgetc();
1521			}
1522		}
1523		if (subtype == 0) {
1524			switch (c) {
1525			case ':':
1526				flags |= VSNUL;
1527				c = pgetc();
1528				/*FALLTHROUGH*/
1529			default:
1530				p = strchr(types, c);
1531				if (p == NULL) {
1532					if (c == '\n' || c == PEOF)
1533						synerror("Unexpected end of line in substitution");
1534					if (flags == VSNUL)
1535						STPUTC(':', out);
1536					STPUTC(c, out);
1537					subtype = VSERROR;
1538				} else
1539					subtype = p - types + VSNORMAL;
1540				break;
1541			case '%':
1542			case '#':
1543				{
1544					int cc = c;
1545					subtype = c == '#' ? VSTRIMLEFT :
1546							     VSTRIMRIGHT;
1547					c = pgetc();
1548					if (c == cc)
1549						subtype++;
1550					else
1551						pungetc();
1552					break;
1553				}
1554			}
1555		} else if (subtype != VSERROR) {
1556			pungetc();
1557		}
1558		STPUTC('=', out);
1559		if (subtype != VSLENGTH && (state[level].syntax == DQSYNTAX ||
1560		    state[level].syntax == ARISYNTAX))
1561			flags |= VSQUOTE;
1562		*(stackblock() + typeloc) = subtype | flags;
1563		if (subtype != VSNORMAL) {
1564			if (level + 1 >= maxnest) {
1565				maxnest *= 2;
1566				if (state == state_static) {
1567					state = parser_temp_alloc(
1568					    maxnest * sizeof(*state));
1569					memcpy(state, state_static,
1570					    MAXNEST_static * sizeof(*state));
1571				} else
1572					state = parser_temp_realloc(state,
1573					    maxnest * sizeof(*state));
1574			}
1575			level++;
1576			state[level].parenlevel = 0;
1577			if (subtype == VSMINUS || subtype == VSPLUS ||
1578			    subtype == VSQUESTION || subtype == VSASSIGN) {
1579				/*
1580				 * For operators that were in the Bourne shell,
1581				 * inherit the double-quote state.
1582				 */
1583				state[level].syntax = state[level - 1].syntax;
1584				state[level].category = TSTATE_VAR_OLD;
1585			} else {
1586				/*
1587				 * The other operators take a pattern,
1588				 * so go to BASESYNTAX.
1589				 * Also, ' and " are now special, even
1590				 * in here documents.
1591				 */
1592				state[level].syntax = BASESYNTAX;
1593				state[level].category = TSTATE_VAR_NEW;
1594				newvarnest++;
1595			}
1596		}
1597	}
1598	goto parsesub_return;
1599}
1600
1601
1602/*
1603 * Parse an arithmetic expansion (indicate start of one and set state)
1604 */
1605parsearith: {
1606
1607	if (level + 1 >= maxnest) {
1608		maxnest *= 2;
1609		if (state == state_static) {
1610			state = parser_temp_alloc(
1611			    maxnest * sizeof(*state));
1612			memcpy(state, state_static,
1613			    MAXNEST_static * sizeof(*state));
1614		} else
1615			state = parser_temp_realloc(state,
1616			    maxnest * sizeof(*state));
1617	}
1618	level++;
1619	state[level].syntax = ARISYNTAX;
1620	state[level].parenlevel = 0;
1621	state[level].category = TSTATE_ARITH;
1622	USTPUTC(CTLARI, out);
1623	if (state[level - 1].syntax == DQSYNTAX)
1624		USTPUTC('"',out);
1625	else
1626		USTPUTC(' ',out);
1627	goto parsearith_return;
1628}
1629
1630} /* end of readtoken */
1631
1632
1633
1634#ifdef mkinit
1635RESET {
1636	tokpushback = 0;
1637	checkkwd = 0;
1638}
1639#endif
1640
1641/*
1642 * Returns true if the text contains nothing to expand (no dollar signs
1643 * or backquotes).
1644 */
1645
1646static int
1647noexpand(char *text)
1648{
1649	char *p;
1650	char c;
1651
1652	p = text;
1653	while ((c = *p++) != '\0') {
1654		if ( c == CTLQUOTEMARK)
1655			continue;
1656		if (c == CTLESC)
1657			p++;
1658		else if (BASESYNTAX[(int)c] == CCTL)
1659			return 0;
1660	}
1661	return 1;
1662}
1663
1664
1665/*
1666 * Return true if the argument is a legal variable name (a letter or
1667 * underscore followed by zero or more letters, underscores, and digits).
1668 */
1669
1670int
1671goodname(const char *name)
1672{
1673	const char *p;
1674
1675	p = name;
1676	if (! is_name(*p))
1677		return 0;
1678	while (*++p) {
1679		if (! is_in_name(*p))
1680			return 0;
1681	}
1682	return 1;
1683}
1684
1685
1686/*
1687 * Called when an unexpected token is read during the parse.  The argument
1688 * is the token that is expected, or -1 if more than one type of token can
1689 * occur at this point.
1690 */
1691
1692static void
1693synexpect(int token)
1694{
1695	char msg[64];
1696
1697	if (token >= 0) {
1698		fmtstr(msg, 64, "%s unexpected (expecting %s)",
1699			tokname[lasttoken], tokname[token]);
1700	} else {
1701		fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1702	}
1703	synerror(msg);
1704}
1705
1706
1707static void
1708synerror(const char *msg)
1709{
1710	if (commandname)
1711		outfmt(out2, "%s: %d: ", commandname, startlinno);
1712	outfmt(out2, "Syntax error: %s\n", msg);
1713	error((char *)NULL);
1714}
1715
1716static void
1717setprompt(int which)
1718{
1719	whichprompt = which;
1720
1721#ifndef NO_HISTORY
1722	if (!el)
1723#endif
1724	{
1725		out2str(getprompt(NULL));
1726		flushout(out2);
1727	}
1728}
1729
1730/*
1731 * called by editline -- any expansions to the prompt
1732 *    should be added here.
1733 */
1734char *
1735getprompt(void *unused __unused)
1736{
1737	static char ps[PROMPTLEN];
1738	char *fmt;
1739	const char *pwd;
1740	int i, trim;
1741	static char internal_error[] = "<internal prompt error>";
1742
1743	/*
1744	 * Select prompt format.
1745	 */
1746	switch (whichprompt) {
1747	case 0:
1748		fmt = nullstr;
1749		break;
1750	case 1:
1751		fmt = ps1val();
1752		break;
1753	case 2:
1754		fmt = ps2val();
1755		break;
1756	default:
1757		return internal_error;
1758	}
1759
1760	/*
1761	 * Format prompt string.
1762	 */
1763	for (i = 0; (i < 127) && (*fmt != '\0'); i++, fmt++)
1764		if (*fmt == '\\')
1765			switch (*++fmt) {
1766
1767				/*
1768				 * Hostname.
1769				 *
1770				 * \h specifies just the local hostname,
1771				 * \H specifies fully-qualified hostname.
1772				 */
1773			case 'h':
1774			case 'H':
1775				ps[i] = '\0';
1776				gethostname(&ps[i], PROMPTLEN - i);
1777				/* Skip to end of hostname. */
1778				trim = (*fmt == 'h') ? '.' : '\0';
1779				while ((ps[i+1] != '\0') && (ps[i+1] != trim))
1780					i++;
1781				break;
1782
1783				/*
1784				 * Working directory.
1785				 *
1786				 * \W specifies just the final component,
1787				 * \w specifies the entire path.
1788				 */
1789			case 'W':
1790			case 'w':
1791				pwd = lookupvar("PWD");
1792				if (pwd == NULL)
1793					pwd = "?";
1794				if (*fmt == 'W' &&
1795				    *pwd == '/' && pwd[1] != '\0')
1796					strlcpy(&ps[i], strrchr(pwd, '/') + 1,
1797					    PROMPTLEN - i);
1798				else
1799					strlcpy(&ps[i], pwd, PROMPTLEN - i);
1800				/* Skip to end of path. */
1801				while (ps[i + 1] != '\0')
1802					i++;
1803				break;
1804
1805				/*
1806				 * Superuser status.
1807				 *
1808				 * '$' for normal users, '#' for root.
1809				 */
1810			case '$':
1811				ps[i] = (geteuid() != 0) ? '$' : '#';
1812				break;
1813
1814				/*
1815				 * A literal \.
1816				 */
1817			case '\\':
1818				ps[i] = '\\';
1819				break;
1820
1821				/*
1822				 * Emit unrecognized formats verbatim.
1823				 */
1824			default:
1825				ps[i++] = '\\';
1826				ps[i] = *fmt;
1827				break;
1828			}
1829		else
1830			ps[i] = *fmt;
1831	ps[i] = '\0';
1832	return (ps);
1833}
1834