1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1991, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Kenneth Almquist.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#ifndef lint
36#if 0
37static char sccsid[] = "@(#)parser.c	8.7 (Berkeley) 5/16/95";
38#endif
39#endif /* not lint */
40#include <sys/cdefs.h>
41__FBSDID("$FreeBSD$");
42
43#include <sys/param.h>
44#include <pwd.h>
45#include <stdlib.h>
46#include <unistd.h>
47#include <stdio.h>
48
49#include "shell.h"
50#include "parser.h"
51#include "nodes.h"
52#include "expand.h"	/* defines rmescapes() */
53#include "syntax.h"
54#include "options.h"
55#include "input.h"
56#include "output.h"
57#include "var.h"
58#include "error.h"
59#include "memalloc.h"
60#include "mystring.h"
61#include "alias.h"
62#include "show.h"
63#include "eval.h"
64#include "exec.h"	/* to check for special builtins */
65#ifndef NO_HISTORY
66#include "myhistedit.h"
67#endif
68
69/*
70 * Shell command parser.
71 */
72
73#define	PROMPTLEN	128
74
75/* values of checkkwd variable */
76#define CHKALIAS	0x1
77#define CHKKWD		0x2
78#define CHKNL		0x4
79
80/* values returned by readtoken */
81#include "token.h"
82
83
84
85struct heredoc {
86	struct heredoc *next;	/* next here document in list */
87	union node *here;		/* redirection node */
88	char *eofmark;		/* string indicating end of input */
89	int striptabs;		/* if set, strip leading tabs */
90};
91
92struct parser_temp {
93	struct parser_temp *next;
94	void *data;
95};
96
97
98static struct heredoc *heredoclist;	/* list of here documents to read */
99static int doprompt;		/* if set, prompt the user */
100static int needprompt;		/* true if interactive and at start of line */
101static int lasttoken;		/* last token read */
102static int tokpushback;		/* last token pushed back */
103static char *wordtext;		/* text of last word returned by readtoken */
104static int checkkwd;
105static struct nodelist *backquotelist;
106static union node *redirnode;
107static struct heredoc *heredoc;
108static int quoteflag;		/* set if (part of) last token was quoted */
109static int startlinno;		/* line # where last token started */
110static int funclinno;		/* line # where the current function started */
111static struct parser_temp *parser_temp;
112
113#define NOEOFMARK ((const char *)&heredoclist)
114
115
116static union node *list(int);
117static union node *andor(void);
118static union node *pipeline(void);
119static union node *command(void);
120static union node *simplecmd(union node **, union node *);
121static union node *makename(void);
122static union node *makebinary(int type, union node *n1, union node *n2);
123static void parsefname(void);
124static void parseheredoc(void);
125static int peektoken(void);
126static int readtoken(void);
127static int xxreadtoken(void);
128static int readtoken1(int, const char *, const char *, int);
129static int noexpand(char *);
130static void consumetoken(int);
131static void synexpect(int) __dead2;
132static void synerror(const char *) __dead2;
133static void setprompt(int);
134static int pgetc_linecont(void);
135static void getusername(char *, size_t);
136
137
138static void *
139parser_temp_alloc(size_t len)
140{
141	struct parser_temp *t;
142
143	INTOFF;
144	t = ckmalloc(sizeof(*t));
145	t->data = NULL;
146	t->next = parser_temp;
147	parser_temp = t;
148	t->data = ckmalloc(len);
149	INTON;
150	return t->data;
151}
152
153
154static void *
155parser_temp_realloc(void *ptr, size_t len)
156{
157	struct parser_temp *t;
158
159	INTOFF;
160	t = parser_temp;
161	if (ptr != t->data)
162		error("bug: parser_temp_realloc misused");
163	t->data = ckrealloc(t->data, len);
164	INTON;
165	return t->data;
166}
167
168
169static void
170parser_temp_free_upto(void *ptr)
171{
172	struct parser_temp *t;
173	int done = 0;
174
175	INTOFF;
176	while (parser_temp != NULL && !done) {
177		t = parser_temp;
178		parser_temp = t->next;
179		done = t->data == ptr;
180		ckfree(t->data);
181		ckfree(t);
182	}
183	INTON;
184	if (!done)
185		error("bug: parser_temp_free_upto misused");
186}
187
188
189static void
190parser_temp_free_all(void)
191{
192	struct parser_temp *t;
193
194	INTOFF;
195	while (parser_temp != NULL) {
196		t = parser_temp;
197		parser_temp = t->next;
198		ckfree(t->data);
199		ckfree(t);
200	}
201	INTON;
202}
203
204
205/*
206 * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
207 * valid parse tree indicating a blank line.)
208 */
209
210union node *
211parsecmd(int interact)
212{
213	int t;
214
215	/* This assumes the parser is not re-entered,
216	 * which could happen if we add command substitution on PS1/PS2.
217	 */
218	parser_temp_free_all();
219	heredoclist = NULL;
220
221	tokpushback = 0;
222	checkkwd = 0;
223	doprompt = interact;
224	if (doprompt)
225		setprompt(1);
226	else
227		setprompt(0);
228	needprompt = 0;
229	t = readtoken();
230	if (t == TEOF)
231		return NEOF;
232	if (t == TNL)
233		return NULL;
234	tokpushback++;
235	return list(1);
236}
237
238
239/*
240 * Read and parse words for wordexp.
241 * Returns a list of NARG nodes; NULL if there are no words.
242 */
243union node *
244parsewordexp(void)
245{
246	union node *n, *first = NULL, **pnext;
247	int t;
248
249	/* This assumes the parser is not re-entered,
250	 * which could happen if we add command substitution on PS1/PS2.
251	 */
252	parser_temp_free_all();
253	heredoclist = NULL;
254
255	tokpushback = 0;
256	checkkwd = 0;
257	doprompt = 0;
258	setprompt(0);
259	needprompt = 0;
260	pnext = &first;
261	while ((t = readtoken()) != TEOF) {
262		if (t != TWORD)
263			synexpect(TWORD);
264		n = makename();
265		*pnext = n;
266		pnext = &n->narg.next;
267	}
268	return first;
269}
270
271
272static union node *
273list(int nlflag)
274{
275	union node *ntop, *n1, *n2, *n3;
276	int tok;
277
278	checkkwd = CHKNL | CHKKWD | CHKALIAS;
279	if (!nlflag && tokendlist[peektoken()])
280		return NULL;
281	ntop = n1 = NULL;
282	for (;;) {
283		n2 = andor();
284		tok = readtoken();
285		if (tok == TBACKGND) {
286			if (n2 != NULL && n2->type == NPIPE) {
287				n2->npipe.backgnd = 1;
288			} else if (n2 != NULL && n2->type == NREDIR) {
289				n2->type = NBACKGND;
290			} else {
291				n3 = (union node *)stalloc(sizeof (struct nredir));
292				n3->type = NBACKGND;
293				n3->nredir.n = n2;
294				n3->nredir.redirect = NULL;
295				n2 = n3;
296			}
297		}
298		if (ntop == NULL)
299			ntop = n2;
300		else if (n1 == NULL) {
301			n1 = makebinary(NSEMI, ntop, n2);
302			ntop = n1;
303		}
304		else {
305			n3 = makebinary(NSEMI, n1->nbinary.ch2, n2);
306			n1->nbinary.ch2 = n3;
307			n1 = n3;
308		}
309		switch (tok) {
310		case TBACKGND:
311		case TSEMI:
312			tok = readtoken();
313			/* FALLTHROUGH */
314		case TNL:
315			if (tok == TNL) {
316				parseheredoc();
317				if (nlflag)
318					return ntop;
319			} else if (tok == TEOF && nlflag) {
320				parseheredoc();
321				return ntop;
322			} else {
323				tokpushback++;
324			}
325			checkkwd = CHKNL | CHKKWD | CHKALIAS;
326			if (!nlflag && tokendlist[peektoken()])
327				return ntop;
328			break;
329		case TEOF:
330			if (heredoclist)
331				parseheredoc();
332			else
333				pungetc();		/* push back EOF on input */
334			return ntop;
335		default:
336			if (nlflag)
337				synexpect(-1);
338			tokpushback++;
339			return ntop;
340		}
341	}
342}
343
344
345
346static union node *
347andor(void)
348{
349	union node *n;
350	int t;
351
352	n = pipeline();
353	for (;;) {
354		if ((t = readtoken()) == TAND) {
355			t = NAND;
356		} else if (t == TOR) {
357			t = NOR;
358		} else {
359			tokpushback++;
360			return n;
361		}
362		n = makebinary(t, n, pipeline());
363	}
364}
365
366
367
368static union node *
369pipeline(void)
370{
371	union node *n1, *n2, *pipenode;
372	struct nodelist *lp, *prev;
373	int negate, t;
374
375	negate = 0;
376	checkkwd = CHKNL | CHKKWD | CHKALIAS;
377	TRACE(("pipeline: entered\n"));
378	while (readtoken() == TNOT)
379		negate = !negate;
380	tokpushback++;
381	n1 = command();
382	if (readtoken() == TPIPE) {
383		pipenode = (union node *)stalloc(sizeof (struct npipe));
384		pipenode->type = NPIPE;
385		pipenode->npipe.backgnd = 0;
386		lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
387		pipenode->npipe.cmdlist = lp;
388		lp->n = n1;
389		do {
390			prev = lp;
391			lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
392			checkkwd = CHKNL | CHKKWD | CHKALIAS;
393			t = readtoken();
394			tokpushback++;
395			if (t == TNOT)
396				lp->n = pipeline();
397			else
398				lp->n = command();
399			prev->next = lp;
400		} while (readtoken() == TPIPE);
401		lp->next = NULL;
402		n1 = pipenode;
403	}
404	tokpushback++;
405	if (negate) {
406		n2 = (union node *)stalloc(sizeof (struct nnot));
407		n2->type = NNOT;
408		n2->nnot.com = n1;
409		return n2;
410	} else
411		return n1;
412}
413
414
415
416static union node *
417command(void)
418{
419	union node *n1, *n2;
420	union node *ap, **app;
421	union node *cp, **cpp;
422	union node *redir, **rpp;
423	int t;
424	int is_subshell;
425
426	checkkwd = CHKNL | CHKKWD | CHKALIAS;
427	is_subshell = 0;
428	redir = NULL;
429	n1 = NULL;
430	rpp = &redir;
431
432	/* Check for redirection which may precede command */
433	while (readtoken() == TREDIR) {
434		*rpp = n2 = redirnode;
435		rpp = &n2->nfile.next;
436		parsefname();
437	}
438	tokpushback++;
439
440	switch (readtoken()) {
441	case TIF:
442		n1 = (union node *)stalloc(sizeof (struct nif));
443		n1->type = NIF;
444		if ((n1->nif.test = list(0)) == NULL)
445			synexpect(-1);
446		consumetoken(TTHEN);
447		n1->nif.ifpart = list(0);
448		n2 = n1;
449		while (readtoken() == TELIF) {
450			n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
451			n2 = n2->nif.elsepart;
452			n2->type = NIF;
453			if ((n2->nif.test = list(0)) == NULL)
454				synexpect(-1);
455			consumetoken(TTHEN);
456			n2->nif.ifpart = list(0);
457		}
458		if (lasttoken == TELSE)
459			n2->nif.elsepart = list(0);
460		else {
461			n2->nif.elsepart = NULL;
462			tokpushback++;
463		}
464		consumetoken(TFI);
465		checkkwd = CHKKWD | CHKALIAS;
466		break;
467	case TWHILE:
468	case TUNTIL:
469		t = lasttoken;
470		if ((n1 = list(0)) == NULL)
471			synexpect(-1);
472		consumetoken(TDO);
473		n1 = makebinary((t == TWHILE)? NWHILE : NUNTIL, n1, list(0));
474		consumetoken(TDONE);
475		checkkwd = CHKKWD | CHKALIAS;
476		break;
477	case TFOR:
478		if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
479			synerror("Bad for loop variable");
480		n1 = (union node *)stalloc(sizeof (struct nfor));
481		n1->type = NFOR;
482		n1->nfor.var = wordtext;
483		while (readtoken() == TNL)
484			;
485		if (lasttoken == TWORD && ! quoteflag && equal(wordtext, "in")) {
486			app = &ap;
487			while (readtoken() == TWORD) {
488				n2 = makename();
489				*app = n2;
490				app = &n2->narg.next;
491			}
492			*app = NULL;
493			n1->nfor.args = ap;
494			if (lasttoken != TNL && lasttoken != TSEMI)
495				synexpect(-1);
496		} else {
497			static char argvars[5] = {
498				CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
499			};
500			n2 = (union node *)stalloc(sizeof (struct narg));
501			n2->type = NARG;
502			n2->narg.text = argvars;
503			n2->narg.backquote = NULL;
504			n2->narg.next = NULL;
505			n1->nfor.args = n2;
506			/*
507			 * Newline or semicolon here is optional (but note
508			 * that the original Bourne shell only allowed NL).
509			 */
510			if (lasttoken != TNL && lasttoken != TSEMI)
511				tokpushback++;
512		}
513		checkkwd = CHKNL | CHKKWD | CHKALIAS;
514		if ((t = readtoken()) == TDO)
515			t = TDONE;
516		else if (t == TBEGIN)
517			t = TEND;
518		else
519			synexpect(-1);
520		n1->nfor.body = list(0);
521		consumetoken(t);
522		checkkwd = CHKKWD | CHKALIAS;
523		break;
524	case TCASE:
525		n1 = (union node *)stalloc(sizeof (struct ncase));
526		n1->type = NCASE;
527		consumetoken(TWORD);
528		n1->ncase.expr = makename();
529		while (readtoken() == TNL);
530		if (lasttoken != TWORD || ! equal(wordtext, "in"))
531			synerror("expecting \"in\"");
532		cpp = &n1->ncase.cases;
533		checkkwd = CHKNL | CHKKWD, readtoken();
534		while (lasttoken != TESAC) {
535			*cpp = cp = (union node *)stalloc(sizeof (struct nclist));
536			cp->type = NCLIST;
537			app = &cp->nclist.pattern;
538			if (lasttoken == TLP)
539				readtoken();
540			for (;;) {
541				*app = ap = makename();
542				checkkwd = CHKNL | CHKKWD;
543				if (readtoken() != TPIPE)
544					break;
545				app = &ap->narg.next;
546				readtoken();
547			}
548			ap->narg.next = NULL;
549			if (lasttoken != TRP)
550				synexpect(TRP);
551			cp->nclist.body = list(0);
552
553			checkkwd = CHKNL | CHKKWD | CHKALIAS;
554			if ((t = readtoken()) != TESAC) {
555				if (t == TENDCASE)
556					;
557				else if (t == TFALLTHRU)
558					cp->type = NCLISTFALLTHRU;
559				else
560					synexpect(TENDCASE);
561				checkkwd = CHKNL | CHKKWD, readtoken();
562			}
563			cpp = &cp->nclist.next;
564		}
565		*cpp = NULL;
566		checkkwd = CHKKWD | CHKALIAS;
567		break;
568	case TLP:
569		n1 = (union node *)stalloc(sizeof (struct nredir));
570		n1->type = NSUBSHELL;
571		n1->nredir.n = list(0);
572		n1->nredir.redirect = NULL;
573		consumetoken(TRP);
574		checkkwd = CHKKWD | CHKALIAS;
575		is_subshell = 1;
576		break;
577	case TBEGIN:
578		n1 = list(0);
579		consumetoken(TEND);
580		checkkwd = CHKKWD | CHKALIAS;
581		break;
582	/* A simple command must have at least one redirection or word. */
583	case TBACKGND:
584	case TSEMI:
585	case TAND:
586	case TOR:
587	case TPIPE:
588	case TENDCASE:
589	case TFALLTHRU:
590	case TEOF:
591	case TNL:
592	case TRP:
593		if (!redir)
594			synexpect(-1);
595	case TWORD:
596		tokpushback++;
597		n1 = simplecmd(rpp, redir);
598		return n1;
599	default:
600		synexpect(-1);
601	}
602
603	/* Now check for redirection which may follow command */
604	while (readtoken() == TREDIR) {
605		*rpp = n2 = redirnode;
606		rpp = &n2->nfile.next;
607		parsefname();
608	}
609	tokpushback++;
610	*rpp = NULL;
611	if (redir) {
612		if (!is_subshell) {
613			n2 = (union node *)stalloc(sizeof (struct nredir));
614			n2->type = NREDIR;
615			n2->nredir.n = n1;
616			n1 = n2;
617		}
618		n1->nredir.redirect = redir;
619	}
620
621	return n1;
622}
623
624
625static union node *
626simplecmd(union node **rpp, union node *redir)
627{
628	union node *args, **app;
629	union node **orig_rpp = rpp;
630	union node *n = NULL;
631	int special;
632	int savecheckkwd;
633
634	/* If we don't have any redirections already, then we must reset */
635	/* rpp to be the address of the local redir variable.  */
636	if (redir == NULL)
637		rpp = &redir;
638
639	args = NULL;
640	app = &args;
641	/*
642	 * We save the incoming value, because we need this for shell
643	 * functions.  There can not be a redirect or an argument between
644	 * the function name and the open parenthesis.
645	 */
646	orig_rpp = rpp;
647
648	savecheckkwd = CHKALIAS;
649
650	for (;;) {
651		checkkwd = savecheckkwd;
652		if (readtoken() == TWORD) {
653			n = makename();
654			*app = n;
655			app = &n->narg.next;
656			if (savecheckkwd != 0 && !isassignment(wordtext))
657				savecheckkwd = 0;
658		} else if (lasttoken == TREDIR) {
659			*rpp = n = redirnode;
660			rpp = &n->nfile.next;
661			parsefname();	/* read name of redirection file */
662		} else if (lasttoken == TLP && app == &args->narg.next
663					    && rpp == orig_rpp) {
664			/* We have a function */
665			consumetoken(TRP);
666			funclinno = plinno;
667			/*
668			 * - Require plain text.
669			 * - Functions with '/' cannot be called.
670			 * - Reject name=().
671			 * - Reject ksh extended glob patterns.
672			 */
673			if (!noexpand(n->narg.text) || quoteflag ||
674			    strchr(n->narg.text, '/') ||
675			    strchr("!%*+-=?@}~",
676				n->narg.text[strlen(n->narg.text) - 1]))
677				synerror("Bad function name");
678			rmescapes(n->narg.text);
679			if (find_builtin(n->narg.text, &special) >= 0 &&
680			    special)
681				synerror("Cannot override a special builtin with a function");
682			n->type = NDEFUN;
683			n->narg.next = command();
684			funclinno = 0;
685			return n;
686		} else {
687			tokpushback++;
688			break;
689		}
690	}
691	*app = NULL;
692	*rpp = NULL;
693	n = (union node *)stalloc(sizeof (struct ncmd));
694	n->type = NCMD;
695	n->ncmd.args = args;
696	n->ncmd.redirect = redir;
697	return n;
698}
699
700static union node *
701makename(void)
702{
703	union node *n;
704
705	n = (union node *)stalloc(sizeof (struct narg));
706	n->type = NARG;
707	n->narg.next = NULL;
708	n->narg.text = wordtext;
709	n->narg.backquote = backquotelist;
710	return n;
711}
712
713static union node *
714makebinary(int type, union node *n1, union node *n2)
715{
716	union node *n;
717
718	n = (union node *)stalloc(sizeof (struct nbinary));
719	n->type = type;
720	n->nbinary.ch1 = n1;
721	n->nbinary.ch2 = n2;
722	return (n);
723}
724
725void
726forcealias(void)
727{
728	checkkwd |= CHKALIAS;
729}
730
731void
732fixredir(union node *n, const char *text, int err)
733{
734	TRACE(("Fix redir %s %d\n", text, err));
735	if (!err)
736		n->ndup.vname = NULL;
737
738	if (is_digit(text[0]) && text[1] == '\0')
739		n->ndup.dupfd = digit_val(text[0]);
740	else if (text[0] == '-' && text[1] == '\0')
741		n->ndup.dupfd = -1;
742	else {
743
744		if (err)
745			synerror("Bad fd number");
746		else
747			n->ndup.vname = makename();
748	}
749}
750
751
752static void
753parsefname(void)
754{
755	union node *n = redirnode;
756
757	consumetoken(TWORD);
758	if (n->type == NHERE) {
759		struct heredoc *here = heredoc;
760		struct heredoc *p;
761
762		if (quoteflag == 0)
763			n->type = NXHERE;
764		TRACE(("Here document %d\n", n->type));
765		if (here->striptabs) {
766			while (*wordtext == '\t')
767				wordtext++;
768		}
769		if (! noexpand(wordtext))
770			synerror("Illegal eof marker for << redirection");
771		rmescapes(wordtext);
772		here->eofmark = wordtext;
773		here->next = NULL;
774		if (heredoclist == NULL)
775			heredoclist = here;
776		else {
777			for (p = heredoclist ; p->next ; p = p->next);
778			p->next = here;
779		}
780	} else if (n->type == NTOFD || n->type == NFROMFD) {
781		fixredir(n, wordtext, 0);
782	} else {
783		n->nfile.fname = makename();
784	}
785}
786
787
788/*
789 * Input any here documents.
790 */
791
792static void
793parseheredoc(void)
794{
795	struct heredoc *here;
796	union node *n;
797
798	while (heredoclist) {
799		here = heredoclist;
800		heredoclist = here->next;
801		if (needprompt) {
802			setprompt(2);
803			needprompt = 0;
804		}
805		readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
806				here->eofmark, here->striptabs);
807		n = makename();
808		here->here->nhere.doc = n;
809	}
810}
811
812static int
813peektoken(void)
814{
815	int t;
816
817	t = readtoken();
818	tokpushback++;
819	return (t);
820}
821
822static int
823readtoken(void)
824{
825	int t;
826	struct alias *ap;
827#ifdef DEBUG
828	int alreadyseen = tokpushback;
829#endif
830
831	top:
832	t = xxreadtoken();
833
834	/*
835	 * eat newlines
836	 */
837	if (checkkwd & CHKNL) {
838		while (t == TNL) {
839			parseheredoc();
840			t = xxreadtoken();
841		}
842	}
843
844	/*
845	 * check for keywords and aliases
846	 */
847	if (t == TWORD && !quoteflag)
848	{
849		const char * const *pp;
850
851		if (checkkwd & CHKKWD)
852			for (pp = parsekwd; *pp; pp++) {
853				if (**pp == *wordtext && equal(*pp, wordtext))
854				{
855					lasttoken = t = pp - parsekwd + KWDOFFSET;
856					TRACE(("keyword %s recognized\n", tokname[t]));
857					goto out;
858				}
859			}
860		if (checkkwd & CHKALIAS &&
861		    (ap = lookupalias(wordtext, 1)) != NULL) {
862			pushstring(ap->val, strlen(ap->val), ap);
863			goto top;
864		}
865	}
866out:
867	if (t != TNOT)
868		checkkwd = 0;
869
870#ifdef DEBUG
871	if (!alreadyseen)
872	    TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
873	else
874	    TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
875#endif
876	return (t);
877}
878
879
880/*
881 * Read the next input token.
882 * If the token is a word, we set backquotelist to the list of cmds in
883 *	backquotes.  We set quoteflag to true if any part of the word was
884 *	quoted.
885 * If the token is TREDIR, then we set redirnode to a structure containing
886 *	the redirection.
887 * In all cases, the variable startlinno is set to the number of the line
888 *	on which the token starts.
889 *
890 * [Change comment:  here documents and internal procedures]
891 * [Readtoken shouldn't have any arguments.  Perhaps we should make the
892 *  word parsing code into a separate routine.  In this case, readtoken
893 *  doesn't need to have any internal procedures, but parseword does.
894 *  We could also make parseoperator in essence the main routine, and
895 *  have parseword (readtoken1?) handle both words and redirection.]
896 */
897
898#define RETURN(token)	return lasttoken = token
899
900static int
901xxreadtoken(void)
902{
903	int c;
904
905	if (tokpushback) {
906		tokpushback = 0;
907		return lasttoken;
908	}
909	if (needprompt) {
910		setprompt(2);
911		needprompt = 0;
912	}
913	startlinno = plinno;
914	for (;;) {	/* until token or start of word found */
915		c = pgetc_macro();
916		switch (c) {
917		case ' ': case '\t':
918			continue;
919		case '#':
920			while ((c = pgetc()) != '\n' && c != PEOF);
921			pungetc();
922			continue;
923		case '\\':
924			if (pgetc() == '\n') {
925				startlinno = ++plinno;
926				if (doprompt)
927					setprompt(2);
928				else
929					setprompt(0);
930				continue;
931			}
932			pungetc();
933			/* FALLTHROUGH */
934		default:
935			return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
936		case '\n':
937			plinno++;
938			needprompt = doprompt;
939			RETURN(TNL);
940		case PEOF:
941			RETURN(TEOF);
942		case '&':
943			if (pgetc_linecont() == '&')
944				RETURN(TAND);
945			pungetc();
946			RETURN(TBACKGND);
947		case '|':
948			if (pgetc_linecont() == '|')
949				RETURN(TOR);
950			pungetc();
951			RETURN(TPIPE);
952		case ';':
953			c = pgetc_linecont();
954			if (c == ';')
955				RETURN(TENDCASE);
956			else if (c == '&')
957				RETURN(TFALLTHRU);
958			pungetc();
959			RETURN(TSEMI);
960		case '(':
961			RETURN(TLP);
962		case ')':
963			RETURN(TRP);
964		}
965	}
966#undef RETURN
967}
968
969
970#define MAXNEST_static 8
971struct tokenstate
972{
973	const char *syntax; /* *SYNTAX */
974	int parenlevel; /* levels of parentheses in arithmetic */
975	enum tokenstate_category
976	{
977		TSTATE_TOP,
978		TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
979		TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
980		TSTATE_ARITH
981	} category;
982};
983
984
985/*
986 * Check to see whether we are at the end of the here document.  When this
987 * is called, c is set to the first character of the next input line.  If
988 * we are at the end of the here document, this routine sets the c to PEOF.
989 * The new value of c is returned.
990 */
991
992static int
993checkend(int c, const char *eofmark, int striptabs)
994{
995	if (striptabs) {
996		while (c == '\t')
997			c = pgetc();
998	}
999	if (c == *eofmark) {
1000		int c2;
1001		const char *q;
1002
1003		for (q = eofmark + 1; c2 = pgetc(), *q != '\0' && c2 == *q; q++)
1004			;
1005		if ((c2 == PEOF || c2 == '\n') && *q == '\0') {
1006			c = PEOF;
1007			if (c2 == '\n') {
1008				plinno++;
1009				needprompt = doprompt;
1010			}
1011		} else {
1012			pungetc();
1013			pushstring(eofmark + 1, q - (eofmark + 1), NULL);
1014		}
1015	} else if (c == '\n' && *eofmark == '\0') {
1016		c = PEOF;
1017		plinno++;
1018		needprompt = doprompt;
1019	}
1020	return (c);
1021}
1022
1023
1024/*
1025 * Parse a redirection operator.  The variable "out" points to a string
1026 * specifying the fd to be redirected.  The variable "c" contains the
1027 * first character of the redirection operator.
1028 */
1029
1030static void
1031parseredir(char *out, int c)
1032{
1033	char fd = *out;
1034	union node *np;
1035
1036	np = (union node *)stalloc(sizeof (struct nfile));
1037	if (c == '>') {
1038		np->nfile.fd = 1;
1039		c = pgetc_linecont();
1040		if (c == '>')
1041			np->type = NAPPEND;
1042		else if (c == '&')
1043			np->type = NTOFD;
1044		else if (c == '|')
1045			np->type = NCLOBBER;
1046		else {
1047			np->type = NTO;
1048			pungetc();
1049		}
1050	} else {	/* c == '<' */
1051		np->nfile.fd = 0;
1052		c = pgetc_linecont();
1053		if (c == '<') {
1054			if (sizeof (struct nfile) != sizeof (struct nhere)) {
1055				np = (union node *)stalloc(sizeof (struct nhere));
1056				np->nfile.fd = 0;
1057			}
1058			np->type = NHERE;
1059			heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1060			heredoc->here = np;
1061			if ((c = pgetc_linecont()) == '-') {
1062				heredoc->striptabs = 1;
1063			} else {
1064				heredoc->striptabs = 0;
1065				pungetc();
1066			}
1067		} else if (c == '&')
1068			np->type = NFROMFD;
1069		else if (c == '>')
1070			np->type = NFROMTO;
1071		else {
1072			np->type = NFROM;
1073			pungetc();
1074		}
1075	}
1076	if (fd != '\0')
1077		np->nfile.fd = digit_val(fd);
1078	redirnode = np;
1079}
1080
1081/*
1082 * Called to parse command substitutions.
1083 */
1084
1085static char *
1086parsebackq(char *out, struct nodelist **pbqlist,
1087		int oldstyle, int dblquote, int quoted)
1088{
1089	struct nodelist **nlpp;
1090	union node *n;
1091	char *volatile str;
1092	struct jmploc jmploc;
1093	struct jmploc *const savehandler = handler;
1094	size_t savelen;
1095	int saveprompt;
1096	const int bq_startlinno = plinno;
1097	char *volatile ostr = NULL;
1098	struct parsefile *const savetopfile = getcurrentfile();
1099	struct heredoc *const saveheredoclist = heredoclist;
1100	struct heredoc *here;
1101
1102	str = NULL;
1103	if (setjmp(jmploc.loc)) {
1104		popfilesupto(savetopfile);
1105		if (str)
1106			ckfree(str);
1107		if (ostr)
1108			ckfree(ostr);
1109		heredoclist = saveheredoclist;
1110		handler = savehandler;
1111		if (exception == EXERROR) {
1112			startlinno = bq_startlinno;
1113			synerror("Error in command substitution");
1114		}
1115		longjmp(handler->loc, 1);
1116	}
1117	INTOFF;
1118	savelen = out - stackblock();
1119	if (savelen > 0) {
1120		str = ckmalloc(savelen);
1121		memcpy(str, stackblock(), savelen);
1122	}
1123	handler = &jmploc;
1124	heredoclist = NULL;
1125	INTON;
1126        if (oldstyle) {
1127                /* We must read until the closing backquote, giving special
1128                   treatment to some slashes, and then push the string and
1129                   reread it as input, interpreting it normally.  */
1130                char *oout;
1131                int c;
1132                int olen;
1133
1134
1135                STARTSTACKSTR(oout);
1136		for (;;) {
1137			if (needprompt) {
1138				setprompt(2);
1139				needprompt = 0;
1140			}
1141			CHECKSTRSPACE(2, oout);
1142			c = pgetc_linecont();
1143			if (c == '`')
1144				break;
1145			switch (c) {
1146			case '\\':
1147				c = pgetc();
1148                                if (c != '\\' && c != '`' && c != '$'
1149                                    && (!dblquote || c != '"'))
1150                                        USTPUTC('\\', oout);
1151				break;
1152
1153			case '\n':
1154				plinno++;
1155				needprompt = doprompt;
1156				break;
1157
1158			case PEOF:
1159			        startlinno = plinno;
1160				synerror("EOF in backquote substitution");
1161 				break;
1162
1163			default:
1164				break;
1165			}
1166			USTPUTC(c, oout);
1167                }
1168                USTPUTC('\0', oout);
1169                olen = oout - stackblock();
1170		INTOFF;
1171		ostr = ckmalloc(olen);
1172		memcpy(ostr, stackblock(), olen);
1173		setinputstring(ostr, 1);
1174		INTON;
1175        }
1176	nlpp = pbqlist;
1177	while (*nlpp)
1178		nlpp = &(*nlpp)->next;
1179	*nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1180	(*nlpp)->next = NULL;
1181
1182	if (oldstyle) {
1183		saveprompt = doprompt;
1184		doprompt = 0;
1185	}
1186
1187	n = list(0);
1188
1189	if (oldstyle) {
1190		if (peektoken() != TEOF)
1191			synexpect(-1);
1192		doprompt = saveprompt;
1193	} else
1194		consumetoken(TRP);
1195
1196	(*nlpp)->n = n;
1197        if (oldstyle) {
1198		/*
1199		 * Start reading from old file again, ignoring any pushed back
1200		 * tokens left from the backquote parsing
1201		 */
1202                popfile();
1203		tokpushback = 0;
1204	}
1205	STARTSTACKSTR(out);
1206	CHECKSTRSPACE(savelen + 1, out);
1207	INTOFF;
1208	if (str) {
1209		memcpy(out, str, savelen);
1210		STADJUST(savelen, out);
1211		ckfree(str);
1212		str = NULL;
1213	}
1214	if (ostr) {
1215		ckfree(ostr);
1216		ostr = NULL;
1217	}
1218	here = saveheredoclist;
1219	if (here != NULL) {
1220		while (here->next != NULL)
1221			here = here->next;
1222		here->next = heredoclist;
1223		heredoclist = saveheredoclist;
1224	}
1225	handler = savehandler;
1226	INTON;
1227	if (quoted)
1228		USTPUTC(CTLBACKQ | CTLQUOTE, out);
1229	else
1230		USTPUTC(CTLBACKQ, out);
1231	return out;
1232}
1233
1234
1235/*
1236 * Called to parse a backslash escape sequence inside $'...'.
1237 * The backslash has already been read.
1238 */
1239static char *
1240readcstyleesc(char *out)
1241{
1242	int c, vc, i, n;
1243	unsigned int v;
1244
1245	c = pgetc();
1246	switch (c) {
1247	case '\0':
1248		synerror("Unterminated quoted string");
1249	case '\n':
1250		plinno++;
1251		if (doprompt)
1252			setprompt(2);
1253		else
1254			setprompt(0);
1255		return out;
1256	case '\\':
1257	case '\'':
1258	case '"':
1259		v = c;
1260		break;
1261	case 'a': v = '\a'; break;
1262	case 'b': v = '\b'; break;
1263	case 'e': v = '\033'; break;
1264	case 'f': v = '\f'; break;
1265	case 'n': v = '\n'; break;
1266	case 'r': v = '\r'; break;
1267	case 't': v = '\t'; break;
1268	case 'v': v = '\v'; break;
1269	case 'x':
1270		  v = 0;
1271		  for (;;) {
1272			  c = pgetc();
1273			  if (c >= '0' && c <= '9')
1274				  v = (v << 4) + c - '0';
1275			  else if (c >= 'A' && c <= 'F')
1276				  v = (v << 4) + c - 'A' + 10;
1277			  else if (c >= 'a' && c <= 'f')
1278				  v = (v << 4) + c - 'a' + 10;
1279			  else
1280				  break;
1281		  }
1282		  pungetc();
1283		  break;
1284	case '0': case '1': case '2': case '3':
1285	case '4': case '5': case '6': case '7':
1286		  v = c - '0';
1287		  c = pgetc();
1288		  if (c >= '0' && c <= '7') {
1289			  v <<= 3;
1290			  v += c - '0';
1291			  c = pgetc();
1292			  if (c >= '0' && c <= '7') {
1293				  v <<= 3;
1294				  v += c - '0';
1295			  } else
1296				  pungetc();
1297		  } else
1298			  pungetc();
1299		  break;
1300	case 'c':
1301		  c = pgetc();
1302		  if (c < 0x3f || c > 0x7a || c == 0x60)
1303			  synerror("Bad escape sequence");
1304		  if (c == '\\' && pgetc() != '\\')
1305			  synerror("Bad escape sequence");
1306		  if (c == '?')
1307			  v = 127;
1308		  else
1309			  v = c & 0x1f;
1310		  break;
1311	case 'u':
1312	case 'U':
1313		  n = c == 'U' ? 8 : 4;
1314		  v = 0;
1315		  for (i = 0; i < n; i++) {
1316			  c = pgetc();
1317			  if (c >= '0' && c <= '9')
1318				  v = (v << 4) + c - '0';
1319			  else if (c >= 'A' && c <= 'F')
1320				  v = (v << 4) + c - 'A' + 10;
1321			  else if (c >= 'a' && c <= 'f')
1322				  v = (v << 4) + c - 'a' + 10;
1323			  else
1324				  synerror("Bad escape sequence");
1325		  }
1326		  if (v == 0 || (v >= 0xd800 && v <= 0xdfff))
1327			  synerror("Bad escape sequence");
1328		  /* We really need iconv here. */
1329		  if (initial_localeisutf8 && v > 127) {
1330			  CHECKSTRSPACE(4, out);
1331			  /*
1332			   * We cannot use wctomb() as the locale may have
1333			   * changed.
1334			   */
1335			  if (v <= 0x7ff) {
1336				  USTPUTC(0xc0 | v >> 6, out);
1337				  USTPUTC(0x80 | (v & 0x3f), out);
1338				  return out;
1339			  } else if (v <= 0xffff) {
1340				  USTPUTC(0xe0 | v >> 12, out);
1341				  USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1342				  USTPUTC(0x80 | (v & 0x3f), out);
1343				  return out;
1344			  } else if (v <= 0x10ffff) {
1345				  USTPUTC(0xf0 | v >> 18, out);
1346				  USTPUTC(0x80 | ((v >> 12) & 0x3f), out);
1347				  USTPUTC(0x80 | ((v >> 6) & 0x3f), out);
1348				  USTPUTC(0x80 | (v & 0x3f), out);
1349				  return out;
1350			  }
1351		  }
1352		  if (v > 127)
1353			  v = '?';
1354		  break;
1355	default:
1356		  synerror("Bad escape sequence");
1357	}
1358	vc = (char)v;
1359	/*
1360	 * We can't handle NUL bytes.
1361	 * POSIX says we should skip till the closing quote.
1362	 */
1363	if (vc == '\0') {
1364		while ((c = pgetc()) != '\'') {
1365			if (c == '\\')
1366				c = pgetc();
1367			if (c == PEOF)
1368				synerror("Unterminated quoted string");
1369			if (c == '\n') {
1370				plinno++;
1371				if (doprompt)
1372					setprompt(2);
1373				else
1374					setprompt(0);
1375			}
1376		}
1377		pungetc();
1378		return out;
1379	}
1380	if (SQSYNTAX[vc] == CCTL)
1381		USTPUTC(CTLESC, out);
1382	USTPUTC(vc, out);
1383	return out;
1384}
1385
1386
1387/*
1388 * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
1389 * is not NULL, read a here document.  In the latter case, eofmark is the
1390 * word which marks the end of the document and striptabs is true if
1391 * leading tabs should be stripped from the document.  The argument firstc
1392 * is the first character of the input token or document.
1393 *
1394 * Because C does not have internal subroutines, I have simulated them
1395 * using goto's to implement the subroutine linkage.  The following macros
1396 * will run code that appears at the end of readtoken1.
1397 */
1398
1399#define PARSESUB()	{goto parsesub; parsesub_return:;}
1400#define	PARSEARITH()	{goto parsearith; parsearith_return:;}
1401
1402static int
1403readtoken1(int firstc, char const *initialsyntax, const char *eofmark,
1404    int striptabs)
1405{
1406	int c = firstc;
1407	char *out;
1408	int len;
1409	struct nodelist *bqlist;
1410	int quotef;
1411	int newvarnest;
1412	int level;
1413	int synentry;
1414	struct tokenstate state_static[MAXNEST_static];
1415	int maxnest = MAXNEST_static;
1416	struct tokenstate *state = state_static;
1417	int sqiscstyle = 0;
1418
1419	startlinno = plinno;
1420	quotef = 0;
1421	bqlist = NULL;
1422	newvarnest = 0;
1423	level = 0;
1424	state[level].syntax = initialsyntax;
1425	state[level].parenlevel = 0;
1426	state[level].category = TSTATE_TOP;
1427
1428	STARTSTACKSTR(out);
1429	loop: {	/* for each line, until end of word */
1430		if (eofmark && eofmark != NOEOFMARK)
1431			/* set c to PEOF if at end of here document */
1432			c = checkend(c, eofmark, striptabs);
1433		for (;;) {	/* until end of line or end of word */
1434			CHECKSTRSPACE(4, out);	/* permit 4 calls to USTPUTC */
1435
1436			synentry = state[level].syntax[c];
1437
1438			switch(synentry) {
1439			case CNL:	/* '\n' */
1440				if (level == 0)
1441					goto endword;	/* exit outer loop */
1442				/* FALLTHROUGH */
1443			case CQNL:
1444				USTPUTC(c, out);
1445				plinno++;
1446				if (doprompt)
1447					setprompt(2);
1448				else
1449					setprompt(0);
1450				c = pgetc();
1451				goto loop;		/* continue outer loop */
1452			case CSBACK:
1453				if (sqiscstyle) {
1454					out = readcstyleesc(out);
1455					break;
1456				}
1457				/* FALLTHROUGH */
1458			case CWORD:
1459				USTPUTC(c, out);
1460				break;
1461			case CCTL:
1462				if (eofmark == NULL || initialsyntax != SQSYNTAX)
1463					USTPUTC(CTLESC, out);
1464				USTPUTC(c, out);
1465				break;
1466			case CBACK:	/* backslash */
1467				c = pgetc();
1468				if (c == PEOF) {
1469					USTPUTC('\\', out);
1470					pungetc();
1471				} else if (c == '\n') {
1472					plinno++;
1473					if (doprompt)
1474						setprompt(2);
1475					else
1476						setprompt(0);
1477				} else {
1478					if (state[level].syntax == DQSYNTAX &&
1479					    c != '\\' && c != '`' && c != '$' &&
1480					    (c != '"' || (eofmark != NULL &&
1481						newvarnest == 0)) &&
1482					    (c != '}' || state[level].category != TSTATE_VAR_OLD))
1483						USTPUTC('\\', out);
1484					if ((eofmark == NULL ||
1485					    newvarnest > 0) &&
1486					    state[level].syntax == BASESYNTAX)
1487						USTPUTC(CTLQUOTEMARK, out);
1488					if (SQSYNTAX[c] == CCTL)
1489						USTPUTC(CTLESC, out);
1490					USTPUTC(c, out);
1491					if ((eofmark == NULL ||
1492					    newvarnest > 0) &&
1493					    state[level].syntax == BASESYNTAX &&
1494					    state[level].category == TSTATE_VAR_OLD)
1495						USTPUTC(CTLQUOTEEND, out);
1496					quotef++;
1497				}
1498				break;
1499			case CSQUOTE:
1500				USTPUTC(CTLQUOTEMARK, out);
1501				state[level].syntax = SQSYNTAX;
1502				sqiscstyle = 0;
1503				break;
1504			case CDQUOTE:
1505				USTPUTC(CTLQUOTEMARK, out);
1506				state[level].syntax = DQSYNTAX;
1507				break;
1508			case CENDQUOTE:
1509				if (eofmark != NULL && newvarnest == 0)
1510					USTPUTC(c, out);
1511				else {
1512					if (state[level].category == TSTATE_VAR_OLD)
1513						USTPUTC(CTLQUOTEEND, out);
1514					state[level].syntax = BASESYNTAX;
1515					quotef++;
1516				}
1517				break;
1518			case CVAR:	/* '$' */
1519				PARSESUB();		/* parse substitution */
1520				break;
1521			case CENDVAR:	/* '}' */
1522				if (level > 0 &&
1523				    ((state[level].category == TSTATE_VAR_OLD &&
1524				      state[level].syntax ==
1525				      state[level - 1].syntax) ||
1526				    (state[level].category == TSTATE_VAR_NEW &&
1527				     state[level].syntax == BASESYNTAX))) {
1528					if (state[level].category == TSTATE_VAR_NEW)
1529						newvarnest--;
1530					level--;
1531					USTPUTC(CTLENDVAR, out);
1532				} else {
1533					USTPUTC(c, out);
1534				}
1535				break;
1536			case CLP:	/* '(' in arithmetic */
1537				state[level].parenlevel++;
1538				USTPUTC(c, out);
1539				break;
1540			case CRP:	/* ')' in arithmetic */
1541				if (state[level].parenlevel > 0) {
1542					USTPUTC(c, out);
1543					--state[level].parenlevel;
1544				} else {
1545					if (pgetc_linecont() == ')') {
1546						if (level > 0 &&
1547						    state[level].category == TSTATE_ARITH) {
1548							level--;
1549							USTPUTC(CTLENDARI, out);
1550						} else
1551							USTPUTC(')', out);
1552					} else {
1553						/*
1554						 * unbalanced parens
1555						 *  (don't 2nd guess - no error)
1556						 */
1557						pungetc();
1558						USTPUTC(')', out);
1559					}
1560				}
1561				break;
1562			case CBQUOTE:	/* '`' */
1563				out = parsebackq(out, &bqlist, 1,
1564				    state[level].syntax == DQSYNTAX &&
1565				    (eofmark == NULL || newvarnest > 0),
1566				    state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
1567				break;
1568			case CEOF:
1569				goto endword;		/* exit outer loop */
1570			case CIGN:
1571				break;
1572			default:
1573				if (level == 0)
1574					goto endword;	/* exit outer loop */
1575				USTPUTC(c, out);
1576			}
1577			c = pgetc_macro();
1578		}
1579	}
1580endword:
1581	if (state[level].syntax == ARISYNTAX)
1582		synerror("Missing '))'");
1583	if (state[level].syntax != BASESYNTAX && eofmark == NULL)
1584		synerror("Unterminated quoted string");
1585	if (state[level].category == TSTATE_VAR_OLD ||
1586	    state[level].category == TSTATE_VAR_NEW) {
1587		startlinno = plinno;
1588		synerror("Missing '}'");
1589	}
1590	if (state != state_static)
1591		parser_temp_free_upto(state);
1592	USTPUTC('\0', out);
1593	len = out - stackblock();
1594	out = stackblock();
1595	if (eofmark == NULL) {
1596		if ((c == '>' || c == '<')
1597		 && quotef == 0
1598		 && len <= 2
1599		 && (*out == '\0' || is_digit(*out))) {
1600			parseredir(out, c);
1601			return lasttoken = TREDIR;
1602		} else {
1603			pungetc();
1604		}
1605	}
1606	quoteflag = quotef;
1607	backquotelist = bqlist;
1608	grabstackblock(len);
1609	wordtext = out;
1610	return lasttoken = TWORD;
1611/* end of readtoken routine */
1612
1613
1614/*
1615 * Parse a substitution.  At this point, we have read the dollar sign
1616 * and nothing else.
1617 */
1618
1619parsesub: {
1620	int subtype;
1621	int typeloc;
1622	int flags;
1623	char *p;
1624	static const char types[] = "}-+?=";
1625	int linno;
1626	int length;
1627	int c1;
1628
1629	c = pgetc_linecont();
1630	if (c == '(') {	/* $(command) or $((arith)) */
1631		if (pgetc_linecont() == '(') {
1632			PARSEARITH();
1633		} else {
1634			pungetc();
1635			out = parsebackq(out, &bqlist, 0,
1636			    state[level].syntax == DQSYNTAX &&
1637			    (eofmark == NULL || newvarnest > 0),
1638			    state[level].syntax == DQSYNTAX ||
1639			    state[level].syntax == ARISYNTAX);
1640		}
1641	} else if (c == '{' || is_name(c) || is_special(c)) {
1642		USTPUTC(CTLVAR, out);
1643		typeloc = out - stackblock();
1644		USTPUTC(VSNORMAL, out);
1645		subtype = VSNORMAL;
1646		flags = 0;
1647		if (c == '{') {
1648			c = pgetc_linecont();
1649			subtype = 0;
1650		}
1651varname:
1652		if (!is_eof(c) && is_name(c)) {
1653			length = 0;
1654			do {
1655				STPUTC(c, out);
1656				c = pgetc_linecont();
1657				length++;
1658			} while (!is_eof(c) && is_in_name(c));
1659			if (length == 6 &&
1660			    strncmp(out - length, "LINENO", length) == 0) {
1661				/* Replace the variable name with the
1662				 * current line number. */
1663				STADJUST(-6, out);
1664				CHECKSTRSPACE(11, out);
1665				linno = plinno;
1666				if (funclinno != 0)
1667					linno -= funclinno - 1;
1668				length = snprintf(out, 11, "%d", linno);
1669				if (length > 10)
1670					length = 10;
1671				out += length;
1672				flags |= VSLINENO;
1673			}
1674		} else if (is_digit(c)) {
1675			if (subtype != VSNORMAL) {
1676				do {
1677					STPUTC(c, out);
1678					c = pgetc_linecont();
1679				} while (is_digit(c));
1680			} else {
1681				USTPUTC(c, out);
1682				c = pgetc_linecont();
1683			}
1684		} else if (is_special(c)) {
1685			c1 = c;
1686			c = pgetc_linecont();
1687			if (subtype == 0 && c1 == '#') {
1688				subtype = VSLENGTH;
1689				if (strchr(types, c) == NULL && c != ':' &&
1690				    c != '#' && c != '%')
1691					goto varname;
1692				c1 = c;
1693				c = pgetc_linecont();
1694				if (c1 != '}' && c == '}') {
1695					pungetc();
1696					c = c1;
1697					goto varname;
1698				}
1699				pungetc();
1700				c = c1;
1701				c1 = '#';
1702				subtype = 0;
1703			}
1704			USTPUTC(c1, out);
1705		} else {
1706			subtype = VSERROR;
1707			if (c == '}')
1708				pungetc();
1709			else if (c == '\n' || c == PEOF)
1710				synerror("Unexpected end of line in substitution");
1711			else if (BASESYNTAX[c] != CCTL)
1712				USTPUTC(c, out);
1713		}
1714		if (subtype == 0) {
1715			switch (c) {
1716			case ':':
1717				flags |= VSNUL;
1718				c = pgetc_linecont();
1719				/*FALLTHROUGH*/
1720			default:
1721				p = strchr(types, c);
1722				if (p == NULL) {
1723					if (c == '\n' || c == PEOF)
1724						synerror("Unexpected end of line in substitution");
1725					if (flags == VSNUL)
1726						STPUTC(':', out);
1727					if (BASESYNTAX[c] != CCTL)
1728						STPUTC(c, out);
1729					subtype = VSERROR;
1730				} else
1731					subtype = p - types + VSNORMAL;
1732				break;
1733			case '%':
1734			case '#':
1735				{
1736					int cc = c;
1737					subtype = c == '#' ? VSTRIMLEFT :
1738							     VSTRIMRIGHT;
1739					c = pgetc_linecont();
1740					if (c == cc)
1741						subtype++;
1742					else
1743						pungetc();
1744					break;
1745				}
1746			}
1747		} else if (subtype != VSERROR) {
1748			if (subtype == VSLENGTH && c != '}')
1749				subtype = VSERROR;
1750			pungetc();
1751		}
1752		STPUTC('=', out);
1753		if (state[level].syntax == DQSYNTAX ||
1754		    state[level].syntax == ARISYNTAX)
1755			flags |= VSQUOTE;
1756		*(stackblock() + typeloc) = subtype | flags;
1757		if (subtype != VSNORMAL) {
1758			if (level + 1 >= maxnest) {
1759				maxnest *= 2;
1760				if (state == state_static) {
1761					state = parser_temp_alloc(
1762					    maxnest * sizeof(*state));
1763					memcpy(state, state_static,
1764					    MAXNEST_static * sizeof(*state));
1765				} else
1766					state = parser_temp_realloc(state,
1767					    maxnest * sizeof(*state));
1768			}
1769			level++;
1770			state[level].parenlevel = 0;
1771			if (subtype == VSMINUS || subtype == VSPLUS ||
1772			    subtype == VSQUESTION || subtype == VSASSIGN) {
1773				/*
1774				 * For operators that were in the Bourne shell,
1775				 * inherit the double-quote state.
1776				 */
1777				state[level].syntax = state[level - 1].syntax;
1778				state[level].category = TSTATE_VAR_OLD;
1779			} else {
1780				/*
1781				 * The other operators take a pattern,
1782				 * so go to BASESYNTAX.
1783				 * Also, ' and " are now special, even
1784				 * in here documents.
1785				 */
1786				state[level].syntax = BASESYNTAX;
1787				state[level].category = TSTATE_VAR_NEW;
1788				newvarnest++;
1789			}
1790		}
1791	} else if (c == '\'' && state[level].syntax == BASESYNTAX) {
1792		/* $'cstylequotes' */
1793		USTPUTC(CTLQUOTEMARK, out);
1794		state[level].syntax = SQSYNTAX;
1795		sqiscstyle = 1;
1796	} else {
1797		USTPUTC('$', out);
1798		pungetc();
1799	}
1800	goto parsesub_return;
1801}
1802
1803
1804/*
1805 * Parse an arithmetic expansion (indicate start of one and set state)
1806 */
1807parsearith: {
1808
1809	if (level + 1 >= maxnest) {
1810		maxnest *= 2;
1811		if (state == state_static) {
1812			state = parser_temp_alloc(
1813			    maxnest * sizeof(*state));
1814			memcpy(state, state_static,
1815			    MAXNEST_static * sizeof(*state));
1816		} else
1817			state = parser_temp_realloc(state,
1818			    maxnest * sizeof(*state));
1819	}
1820	level++;
1821	state[level].syntax = ARISYNTAX;
1822	state[level].parenlevel = 0;
1823	state[level].category = TSTATE_ARITH;
1824	USTPUTC(CTLARI, out);
1825	if (state[level - 1].syntax == DQSYNTAX)
1826		USTPUTC('"',out);
1827	else
1828		USTPUTC(' ',out);
1829	goto parsearith_return;
1830}
1831
1832} /* end of readtoken */
1833
1834
1835/*
1836 * Returns true if the text contains nothing to expand (no dollar signs
1837 * or backquotes).
1838 */
1839
1840static int
1841noexpand(char *text)
1842{
1843	char *p;
1844	char c;
1845
1846	p = text;
1847	while ((c = *p++) != '\0') {
1848		if ( c == CTLQUOTEMARK)
1849			continue;
1850		if (c == CTLESC)
1851			p++;
1852		else if (BASESYNTAX[(int)c] == CCTL)
1853			return 0;
1854	}
1855	return 1;
1856}
1857
1858
1859/*
1860 * Return true if the argument is a legal variable name (a letter or
1861 * underscore followed by zero or more letters, underscores, and digits).
1862 */
1863
1864int
1865goodname(const char *name)
1866{
1867	const char *p;
1868
1869	p = name;
1870	if (! is_name(*p))
1871		return 0;
1872	while (*++p) {
1873		if (! is_in_name(*p))
1874			return 0;
1875	}
1876	return 1;
1877}
1878
1879
1880int
1881isassignment(const char *p)
1882{
1883	if (!is_name(*p))
1884		return 0;
1885	p++;
1886	for (;;) {
1887		if (*p == '=')
1888			return 1;
1889		else if (!is_in_name(*p))
1890			return 0;
1891		p++;
1892	}
1893}
1894
1895
1896static void
1897consumetoken(int token)
1898{
1899	if (readtoken() != token)
1900		synexpect(token);
1901}
1902
1903
1904/*
1905 * Called when an unexpected token is read during the parse.  The argument
1906 * is the token that is expected, or -1 if more than one type of token can
1907 * occur at this point.
1908 */
1909
1910static void
1911synexpect(int token)
1912{
1913	char msg[64];
1914
1915	if (token >= 0) {
1916		fmtstr(msg, 64, "%s unexpected (expecting %s)",
1917			tokname[lasttoken], tokname[token]);
1918	} else {
1919		fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1920	}
1921	synerror(msg);
1922}
1923
1924
1925static void
1926synerror(const char *msg)
1927{
1928	if (commandname)
1929		outfmt(out2, "%s: %d: ", commandname, startlinno);
1930	else if (arg0)
1931		outfmt(out2, "%s: ", arg0);
1932	outfmt(out2, "Syntax error: %s\n", msg);
1933	error((char *)NULL);
1934}
1935
1936static void
1937setprompt(int which)
1938{
1939	whichprompt = which;
1940	if (which == 0)
1941		return;
1942
1943#ifndef NO_HISTORY
1944	if (!el)
1945#endif
1946	{
1947		out2str(getprompt(NULL));
1948		flushout(out2);
1949	}
1950}
1951
1952static int
1953pgetc_linecont(void)
1954{
1955	int c;
1956
1957	while ((c = pgetc_macro()) == '\\') {
1958		c = pgetc();
1959		if (c == '\n') {
1960			plinno++;
1961			if (doprompt)
1962				setprompt(2);
1963			else
1964				setprompt(0);
1965		} else {
1966			pungetc();
1967			/* Allow the backslash to be pushed back. */
1968			pushstring("\\", 1, NULL);
1969			return (pgetc());
1970		}
1971	}
1972	return (c);
1973}
1974
1975
1976static struct passwd *
1977getpwlogin(void)
1978{
1979	const char *login;
1980
1981	login = getlogin();
1982	if (login == NULL)
1983		return (NULL);
1984
1985	return (getpwnam(login));
1986}
1987
1988
1989static void
1990getusername(char *name, size_t namelen)
1991{
1992	static char cached_name[MAXLOGNAME];
1993	struct passwd *pw;
1994	uid_t euid;
1995
1996	if (cached_name[0] == '\0') {
1997		euid = geteuid();
1998
1999		/*
2000		 * Handle the case when there is more than one
2001		 * login with the same UID, or when the login
2002		 * returned by getlogin(2) does no longer match
2003		 * the current UID.
2004		 */
2005		pw = getpwlogin();
2006		if (pw == NULL || pw->pw_uid != euid)
2007			pw = getpwuid(euid);
2008
2009		if (pw != NULL) {
2010			strlcpy(cached_name, pw->pw_name,
2011			    sizeof(cached_name));
2012		} else {
2013			snprintf(cached_name, sizeof(cached_name),
2014			    "%u", euid);
2015		}
2016	}
2017
2018	strlcpy(name, cached_name, namelen);
2019}
2020
2021
2022/*
2023 * called by editline -- any expansions to the prompt
2024 *    should be added here.
2025 */
2026char *
2027getprompt(void *unused __unused)
2028{
2029	static char ps[PROMPTLEN];
2030	const char *fmt;
2031	const char *home;
2032	const char *pwd;
2033	size_t homelen;
2034	int i, trim;
2035	static char internal_error[] = "??";
2036
2037	/*
2038	 * Select prompt format.
2039	 */
2040	switch (whichprompt) {
2041	case 0:
2042		fmt = "";
2043		break;
2044	case 1:
2045		fmt = ps1val();
2046		break;
2047	case 2:
2048		fmt = ps2val();
2049		break;
2050	default:
2051		return internal_error;
2052	}
2053
2054	/*
2055	 * Format prompt string.
2056	 */
2057	for (i = 0; (i < PROMPTLEN - 1) && (*fmt != '\0'); i++, fmt++)
2058		if (*fmt == '\\')
2059			switch (*++fmt) {
2060
2061				/*
2062				 * Hostname.
2063				 *
2064				 * \h specifies just the local hostname,
2065				 * \H specifies fully-qualified hostname.
2066				 */
2067			case 'h':
2068			case 'H':
2069				ps[i] = '\0';
2070				gethostname(&ps[i], PROMPTLEN - i - 1);
2071				ps[PROMPTLEN - 1] = '\0';
2072				/* Skip to end of hostname. */
2073				trim = (*fmt == 'h') ? '.' : '\0';
2074				while ((ps[i] != '\0') && (ps[i] != trim))
2075					i++;
2076				--i;
2077				break;
2078
2079				/*
2080				 * User name.
2081				 */
2082			case 'u':
2083				ps[i] = '\0';
2084				getusername(&ps[i], PROMPTLEN - i);
2085				/* Skip to end of username. */
2086				while (ps[i + 1] != '\0')
2087					i++;
2088				break;
2089
2090				/*
2091				 * Working directory.
2092				 *
2093				 * \W specifies just the final component,
2094				 * \w specifies the entire path.
2095				 */
2096			case 'W':
2097			case 'w':
2098				pwd = lookupvar("PWD");
2099				if (pwd == NULL || *pwd == '\0')
2100					pwd = "?";
2101				if (*fmt == 'W' &&
2102				    *pwd == '/' && pwd[1] != '\0')
2103					strlcpy(&ps[i], strrchr(pwd, '/') + 1,
2104					    PROMPTLEN - i);
2105				else {
2106					home = lookupvar("HOME");
2107					if (home != NULL)
2108						homelen = strlen(home);
2109					if (home != NULL &&
2110					    strcmp(home, "/") != 0 &&
2111					    strncmp(pwd, home, homelen) == 0 &&
2112					    (pwd[homelen] == '/' ||
2113					    pwd[homelen] == '\0')) {
2114						strlcpy(&ps[i], "~",
2115						    PROMPTLEN - i);
2116						strlcpy(&ps[i + 1],
2117						    pwd + homelen,
2118						    PROMPTLEN - i - 1);
2119					} else {
2120						strlcpy(&ps[i], pwd, PROMPTLEN - i);
2121					}
2122				}
2123				/* Skip to end of path. */
2124				while (ps[i + 1] != '\0')
2125					i++;
2126				break;
2127
2128				/*
2129				 * Superuser status.
2130				 *
2131				 * '$' for normal users, '#' for root.
2132				 */
2133			case '$':
2134				ps[i] = (geteuid() != 0) ? '$' : '#';
2135				break;
2136
2137				/*
2138				 * A literal \.
2139				 */
2140			case '\\':
2141				ps[i] = '\\';
2142				break;
2143
2144				/*
2145				 * Emit unrecognized formats verbatim.
2146				 */
2147			default:
2148				ps[i] = '\\';
2149				if (i < PROMPTLEN - 2)
2150					ps[++i] = *fmt;
2151				break;
2152			}
2153		else
2154			ps[i] = *fmt;
2155	ps[i] = '\0';
2156	return (ps);
2157}
2158
2159
2160const char *
2161expandstr(const char *ps)
2162{
2163	union node n;
2164	struct jmploc jmploc;
2165	struct jmploc *const savehandler = handler;
2166	const int saveprompt = doprompt;
2167	struct parsefile *const savetopfile = getcurrentfile();
2168	struct parser_temp *const saveparser_temp = parser_temp;
2169	const char *result = NULL;
2170
2171	if (!setjmp(jmploc.loc)) {
2172		handler = &jmploc;
2173		parser_temp = NULL;
2174		setinputstring(ps, 1);
2175		doprompt = 0;
2176		readtoken1(pgetc(), DQSYNTAX, NOEOFMARK, 0);
2177		if (backquotelist != NULL)
2178			error("Command substitution not allowed here");
2179
2180		n.narg.type = NARG;
2181		n.narg.next = NULL;
2182		n.narg.text = wordtext;
2183		n.narg.backquote = backquotelist;
2184
2185		expandarg(&n, NULL, 0);
2186		result = stackblock();
2187		INTOFF;
2188	}
2189	handler = savehandler;
2190	doprompt = saveprompt;
2191	popfilesupto(savetopfile);
2192	if (parser_temp != saveparser_temp) {
2193		parser_temp_free_all();
2194		parser_temp = saveparser_temp;
2195	}
2196	if (result != NULL) {
2197		INTON;
2198	} else if (exception == EXINT)
2199		raise(SIGINT);
2200	return result;
2201}
2202