parser.c revision 193222 
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 193222 2009-06-01 11:02:09Z rse $");
40
41#include <stdlib.h>
42#include <unistd.h>
43
44#include "shell.h"
45#include "parser.h"
46#include "nodes.h"
47#include "expand.h"	/* defines rmescapes() */
48#include "syntax.h"
49#include "options.h"
50#include "input.h"
51#include "output.h"
52#include "var.h"
53#include "error.h"
54#include "memalloc.h"
55#include "mystring.h"
56#include "alias.h"
57#include "show.h"
58#include "eval.h"
59#ifndef NO_HISTORY
60#include "myhistedit.h"
61#endif
62
63/*
64 * Shell command parser.
65 */
66
67#define	EOFMARKLEN	79
68#define	PROMPTLEN	128
69
70/* values returned by readtoken */
71#include "token.h"
72
73
74
75struct heredoc {
76	struct heredoc *next;	/* next here document in list */
77	union node *here;		/* redirection node */
78	char *eofmark;		/* string indicating end of input */
79	int striptabs;		/* if set, strip leading tabs */
80};
81
82
83
84STATIC struct heredoc *heredoclist;	/* list of here documents to read */
85STATIC int parsebackquote;	/* nonzero if we are inside backquotes */
86STATIC int doprompt;		/* if set, prompt the user */
87STATIC int needprompt;		/* true if interactive and at start of line */
88STATIC int lasttoken;		/* last token read */
89MKINIT int tokpushback;		/* last token pushed back */
90STATIC char *wordtext;		/* text of last word returned by readtoken */
91MKINIT int checkkwd;            /* 1 == check for kwds, 2 == also eat newlines */
92STATIC struct nodelist *backquotelist;
93STATIC union node *redirnode;
94STATIC struct heredoc *heredoc;
95STATIC int quoteflag;		/* set if (part of) last token was quoted */
96STATIC int startlinno;		/* line # where last token started */
97STATIC int funclinno;		/* line # where the current function started */
98
99/* XXX When 'noaliases' is set to one, no alias expansion takes place. */
100static int noaliases = 0;
101
102
103STATIC union node *list(int);
104STATIC union node *andor(void);
105STATIC union node *pipeline(void);
106STATIC union node *command(void);
107STATIC union node *simplecmd(union node **, union node *);
108STATIC union node *makename(void);
109STATIC void parsefname(void);
110STATIC void parseheredoc(void);
111STATIC int peektoken(void);
112STATIC int readtoken(void);
113STATIC int xxreadtoken(void);
114STATIC int readtoken1(int, char const *, char *, int);
115STATIC int noexpand(char *);
116STATIC void synexpect(int);
117STATIC void synerror(char *);
118STATIC void setprompt(int);
119
120
121/*
122 * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
123 * valid parse tree indicating a blank line.)
124 */
125
126union node *
127parsecmd(int interact)
128{
129	int t;
130
131	tokpushback = 0;
132	doprompt = interact;
133	if (doprompt)
134		setprompt(1);
135	else
136		setprompt(0);
137	needprompt = 0;
138	t = readtoken();
139	if (t == TEOF)
140		return NEOF;
141	if (t == TNL)
142		return NULL;
143	tokpushback++;
144	return list(1);
145}
146
147
148STATIC union node *
149list(int nlflag)
150{
151	union node *n1, *n2, *n3;
152	int tok;
153
154	checkkwd = 2;
155	if (nlflag == 0 && tokendlist[peektoken()])
156		return NULL;
157	n1 = NULL;
158	for (;;) {
159		n2 = andor();
160		tok = readtoken();
161		if (tok == TBACKGND) {
162			if (n2->type == NCMD || n2->type == NPIPE) {
163				n2->ncmd.backgnd = 1;
164			} else if (n2->type == NREDIR) {
165				n2->type = NBACKGND;
166			} else {
167				n3 = (union node *)stalloc(sizeof (struct nredir));
168				n3->type = NBACKGND;
169				n3->nredir.n = n2;
170				n3->nredir.redirect = NULL;
171				n2 = n3;
172			}
173		}
174		if (n1 == NULL) {
175			n1 = n2;
176		}
177		else {
178			n3 = (union node *)stalloc(sizeof (struct nbinary));
179			n3->type = NSEMI;
180			n3->nbinary.ch1 = n1;
181			n3->nbinary.ch2 = n2;
182			n1 = n3;
183		}
184		switch (tok) {
185		case TBACKGND:
186		case TSEMI:
187			tok = readtoken();
188			/* FALLTHROUGH */
189		case TNL:
190			if (tok == TNL) {
191				parseheredoc();
192				if (nlflag)
193					return n1;
194			} else {
195				tokpushback++;
196			}
197			checkkwd = 2;
198			if (tokendlist[peektoken()])
199				return n1;
200			break;
201		case TEOF:
202			if (heredoclist)
203				parseheredoc();
204			else
205				pungetc();		/* push back EOF on input */
206			return n1;
207		default:
208			if (nlflag)
209				synexpect(-1);
210			tokpushback++;
211			return n1;
212		}
213	}
214}
215
216
217
218STATIC union node *
219andor(void)
220{
221	union node *n1, *n2, *n3;
222	int t;
223
224	n1 = pipeline();
225	for (;;) {
226		if ((t = readtoken()) == TAND) {
227			t = NAND;
228		} else if (t == TOR) {
229			t = NOR;
230		} else {
231			tokpushback++;
232			return n1;
233		}
234		n2 = pipeline();
235		n3 = (union node *)stalloc(sizeof (struct nbinary));
236		n3->type = t;
237		n3->nbinary.ch1 = n1;
238		n3->nbinary.ch2 = n2;
239		n1 = n3;
240	}
241}
242
243
244
245STATIC union node *
246pipeline(void)
247{
248	union node *n1, *n2, *pipenode;
249	struct nodelist *lp, *prev;
250	int negate;
251
252	negate = 0;
253	checkkwd = 2;
254	TRACE(("pipeline: entered\n"));
255	while (readtoken() == TNOT)
256		negate = !negate;
257	tokpushback++;
258	n1 = command();
259	if (readtoken() == TPIPE) {
260		pipenode = (union node *)stalloc(sizeof (struct npipe));
261		pipenode->type = NPIPE;
262		pipenode->npipe.backgnd = 0;
263		lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
264		pipenode->npipe.cmdlist = lp;
265		lp->n = n1;
266		do {
267			prev = lp;
268			lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
269			lp->n = command();
270			prev->next = lp;
271		} while (readtoken() == TPIPE);
272		lp->next = NULL;
273		n1 = pipenode;
274	}
275	tokpushback++;
276	if (negate) {
277		n2 = (union node *)stalloc(sizeof (struct nnot));
278		n2->type = NNOT;
279		n2->nnot.com = n1;
280		return n2;
281	} else
282		return n1;
283}
284
285
286
287STATIC union node *
288command(void)
289{
290	union node *n1, *n2;
291	union node *ap, **app;
292	union node *cp, **cpp;
293	union node *redir, **rpp;
294	int t, negate = 0;
295
296	checkkwd = 2;
297	redir = NULL;
298	n1 = NULL;
299	rpp = &redir;
300
301	/* Check for redirection which may precede command */
302	while (readtoken() == TREDIR) {
303		*rpp = n2 = redirnode;
304		rpp = &n2->nfile.next;
305		parsefname();
306	}
307	tokpushback++;
308
309	while (readtoken() == TNOT) {
310		TRACE(("command: TNOT recognized\n"));
311		negate = !negate;
312	}
313	tokpushback++;
314
315	switch (readtoken()) {
316	case TIF:
317		n1 = (union node *)stalloc(sizeof (struct nif));
318		n1->type = NIF;
319		if ((n1->nif.test = list(0)) == NULL)
320			synexpect(-1);
321		if (readtoken() != TTHEN)
322			synexpect(TTHEN);
323		n1->nif.ifpart = list(0);
324		n2 = n1;
325		while (readtoken() == TELIF) {
326			n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
327			n2 = n2->nif.elsepart;
328			n2->type = NIF;
329			if ((n2->nif.test = list(0)) == NULL)
330				synexpect(-1);
331			if (readtoken() != TTHEN)
332				synexpect(TTHEN);
333			n2->nif.ifpart = list(0);
334		}
335		if (lasttoken == TELSE)
336			n2->nif.elsepart = list(0);
337		else {
338			n2->nif.elsepart = NULL;
339			tokpushback++;
340		}
341		if (readtoken() != TFI)
342			synexpect(TFI);
343		checkkwd = 1;
344		break;
345	case TWHILE:
346	case TUNTIL: {
347		int got;
348		n1 = (union node *)stalloc(sizeof (struct nbinary));
349		n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
350		if ((n1->nbinary.ch1 = list(0)) == NULL)
351			synexpect(-1);
352		if ((got=readtoken()) != TDO) {
353TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
354			synexpect(TDO);
355		}
356		n1->nbinary.ch2 = list(0);
357		if (readtoken() != TDONE)
358			synexpect(TDONE);
359		checkkwd = 1;
360		break;
361	}
362	case TFOR:
363		if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
364			synerror("Bad for loop variable");
365		n1 = (union node *)stalloc(sizeof (struct nfor));
366		n1->type = NFOR;
367		n1->nfor.var = wordtext;
368		if (readtoken() == TWORD && ! quoteflag && equal(wordtext, "in")) {
369			app = &ap;
370			while (readtoken() == TWORD) {
371				n2 = (union node *)stalloc(sizeof (struct narg));
372				n2->type = NARG;
373				n2->narg.text = wordtext;
374				n2->narg.backquote = backquotelist;
375				*app = n2;
376				app = &n2->narg.next;
377			}
378			*app = NULL;
379			n1->nfor.args = ap;
380			if (lasttoken != TNL && lasttoken != TSEMI)
381				synexpect(-1);
382		} else {
383			static char argvars[5] = {
384				CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
385			};
386			n2 = (union node *)stalloc(sizeof (struct narg));
387			n2->type = NARG;
388			n2->narg.text = argvars;
389			n2->narg.backquote = NULL;
390			n2->narg.next = NULL;
391			n1->nfor.args = n2;
392			/*
393			 * Newline or semicolon here is optional (but note
394			 * that the original Bourne shell only allowed NL).
395			 */
396			if (lasttoken != TNL && lasttoken != TSEMI)
397				tokpushback++;
398		}
399		checkkwd = 2;
400		if ((t = readtoken()) == TDO)
401			t = TDONE;
402		else if (t == TBEGIN)
403			t = TEND;
404		else
405			synexpect(-1);
406		n1->nfor.body = list(0);
407		if (readtoken() != t)
408			synexpect(t);
409		checkkwd = 1;
410		break;
411	case TCASE:
412		n1 = (union node *)stalloc(sizeof (struct ncase));
413		n1->type = NCASE;
414		if (readtoken() != TWORD)
415			synexpect(TWORD);
416		n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
417		n2->type = NARG;
418		n2->narg.text = wordtext;
419		n2->narg.backquote = backquotelist;
420		n2->narg.next = NULL;
421		while (readtoken() == TNL);
422		if (lasttoken != TWORD || ! equal(wordtext, "in"))
423			synerror("expecting \"in\"");
424		cpp = &n1->ncase.cases;
425		noaliases = 1;	/* turn off alias expansion */
426		checkkwd = 2, readtoken();
427		while (lasttoken != TESAC) {
428			*cpp = cp = (union node *)stalloc(sizeof (struct nclist));
429			cp->type = NCLIST;
430			app = &cp->nclist.pattern;
431			if (lasttoken == TLP)
432				readtoken();
433			for (;;) {
434				*app = ap = (union node *)stalloc(sizeof (struct narg));
435				ap->type = NARG;
436				ap->narg.text = wordtext;
437				ap->narg.backquote = backquotelist;
438				if (checkkwd = 2, readtoken() != TPIPE)
439					break;
440				app = &ap->narg.next;
441				readtoken();
442			}
443			ap->narg.next = NULL;
444			if (lasttoken != TRP)
445				noaliases = 0, synexpect(TRP);
446			cp->nclist.body = list(0);
447
448			checkkwd = 2;
449			if ((t = readtoken()) != TESAC) {
450				if (t != TENDCASE)
451					noaliases = 0, synexpect(TENDCASE);
452				else
453					checkkwd = 2, readtoken();
454			}
455			cpp = &cp->nclist.next;
456		}
457		noaliases = 0;	/* reset alias expansion */
458		*cpp = NULL;
459		checkkwd = 1;
460		break;
461	case TLP:
462		n1 = (union node *)stalloc(sizeof (struct nredir));
463		n1->type = NSUBSHELL;
464		n1->nredir.n = list(0);
465		n1->nredir.redirect = NULL;
466		if (readtoken() != TRP)
467			synexpect(TRP);
468		checkkwd = 1;
469		break;
470	case TBEGIN:
471		n1 = list(0);
472		if (readtoken() != TEND)
473			synexpect(TEND);
474		checkkwd = 1;
475		break;
476	/* Handle an empty command like other simple commands.  */
477	case TSEMI:
478	case TAND:
479	case TOR:
480		/*
481		 * An empty command before a ; doesn't make much sense, and
482		 * should certainly be disallowed in the case of `if ;'.
483		 */
484		if (!redir)
485			synexpect(-1);
486	case TNL:
487	case TEOF:
488	case TWORD:
489	case TRP:
490		tokpushback++;
491		n1 = simplecmd(rpp, redir);
492		goto checkneg;
493	default:
494		synexpect(-1);
495	}
496
497	/* Now check for redirection which may follow command */
498	while (readtoken() == TREDIR) {
499		*rpp = n2 = redirnode;
500		rpp = &n2->nfile.next;
501		parsefname();
502	}
503	tokpushback++;
504	*rpp = NULL;
505	if (redir) {
506		if (n1->type != NSUBSHELL) {
507			n2 = (union node *)stalloc(sizeof (struct nredir));
508			n2->type = NREDIR;
509			n2->nredir.n = n1;
510			n1 = n2;
511		}
512		n1->nredir.redirect = redir;
513	}
514
515checkneg:
516	if (negate) {
517		n2 = (union node *)stalloc(sizeof (struct nnot));
518		n2->type = NNOT;
519		n2->nnot.com = n1;
520		return n2;
521	}
522	else
523		return n1;
524}
525
526
527STATIC union node *
528simplecmd(union node **rpp, union node *redir)
529{
530	union node *args, **app;
531	union node **orig_rpp = rpp;
532	union node *n = NULL, *n2;
533	int negate = 0;
534
535	/* If we don't have any redirections already, then we must reset */
536	/* rpp to be the address of the local redir variable.  */
537	if (redir == 0)
538		rpp = &redir;
539
540	args = NULL;
541	app = &args;
542	/*
543	 * We save the incoming value, because we need this for shell
544	 * functions.  There can not be a redirect or an argument between
545	 * the function name and the open parenthesis.
546	 */
547	orig_rpp = rpp;
548
549	while (readtoken() == TNOT) {
550		TRACE(("command: TNOT recognized\n"));
551		negate = !negate;
552	}
553	tokpushback++;
554
555	for (;;) {
556		if (readtoken() == TWORD) {
557			n = (union node *)stalloc(sizeof (struct narg));
558			n->type = NARG;
559			n->narg.text = wordtext;
560			n->narg.backquote = backquotelist;
561			*app = n;
562			app = &n->narg.next;
563		} else if (lasttoken == TREDIR) {
564			*rpp = n = redirnode;
565			rpp = &n->nfile.next;
566			parsefname();	/* read name of redirection file */
567		} else if (lasttoken == TLP && app == &args->narg.next
568					    && rpp == orig_rpp) {
569			/* We have a function */
570			if (readtoken() != TRP)
571				synexpect(TRP);
572			funclinno = plinno;
573#ifdef notdef
574			if (! goodname(n->narg.text))
575				synerror("Bad function name");
576#endif
577			n->type = NDEFUN;
578			n->narg.next = command();
579			funclinno = 0;
580			goto checkneg;
581		} else {
582			tokpushback++;
583			break;
584		}
585	}
586	*app = NULL;
587	*rpp = NULL;
588	n = (union node *)stalloc(sizeof (struct ncmd));
589	n->type = NCMD;
590	n->ncmd.backgnd = 0;
591	n->ncmd.args = args;
592	n->ncmd.redirect = redir;
593
594checkneg:
595	if (negate) {
596		n2 = (union node *)stalloc(sizeof (struct nnot));
597		n2->type = NNOT;
598		n2->nnot.com = n;
599		return n2;
600	}
601	else
602		return n;
603}
604
605STATIC union node *
606makename(void)
607{
608	union node *n;
609
610	n = (union node *)stalloc(sizeof (struct narg));
611	n->type = NARG;
612	n->narg.next = NULL;
613	n->narg.text = wordtext;
614	n->narg.backquote = backquotelist;
615	return n;
616}
617
618void fixredir(union node *n, const char *text, int err)
619{
620	TRACE(("Fix redir %s %d\n", text, err));
621	if (!err)
622		n->ndup.vname = NULL;
623
624	if (is_digit(text[0]) && text[1] == '\0')
625		n->ndup.dupfd = digit_val(text[0]);
626	else if (text[0] == '-' && text[1] == '\0')
627		n->ndup.dupfd = -1;
628	else {
629
630		if (err)
631			synerror("Bad fd number");
632		else
633			n->ndup.vname = makename();
634	}
635}
636
637
638STATIC void
639parsefname(void)
640{
641	union node *n = redirnode;
642
643	if (readtoken() != TWORD)
644		synexpect(-1);
645	if (n->type == NHERE) {
646		struct heredoc *here = heredoc;
647		struct heredoc *p;
648		int i;
649
650		if (quoteflag == 0)
651			n->type = NXHERE;
652		TRACE(("Here document %d\n", n->type));
653		if (here->striptabs) {
654			while (*wordtext == '\t')
655				wordtext++;
656		}
657		if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
658			synerror("Illegal eof marker for << redirection");
659		rmescapes(wordtext);
660		here->eofmark = wordtext;
661		here->next = NULL;
662		if (heredoclist == NULL)
663			heredoclist = here;
664		else {
665			for (p = heredoclist ; p->next ; p = p->next);
666			p->next = here;
667		}
668	} else if (n->type == NTOFD || n->type == NFROMFD) {
669		fixredir(n, wordtext, 0);
670	} else {
671		n->nfile.fname = makename();
672	}
673}
674
675
676/*
677 * Input any here documents.
678 */
679
680STATIC void
681parseheredoc(void)
682{
683	struct heredoc *here;
684	union node *n;
685
686	while (heredoclist) {
687		here = heredoclist;
688		heredoclist = here->next;
689		if (needprompt) {
690			setprompt(2);
691			needprompt = 0;
692		}
693		readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
694				here->eofmark, here->striptabs);
695		n = (union node *)stalloc(sizeof (struct narg));
696		n->narg.type = NARG;
697		n->narg.next = NULL;
698		n->narg.text = wordtext;
699		n->narg.backquote = backquotelist;
700		here->here->nhere.doc = n;
701	}
702}
703
704STATIC int
705peektoken(void)
706{
707	int t;
708
709	t = readtoken();
710	tokpushback++;
711	return (t);
712}
713
714STATIC int
715readtoken(void)
716{
717	int t;
718	int savecheckkwd = checkkwd;
719	struct alias *ap;
720#ifdef DEBUG
721	int alreadyseen = tokpushback;
722#endif
723
724	top:
725	t = xxreadtoken();
726
727	if (checkkwd) {
728		/*
729		 * eat newlines
730		 */
731		if (checkkwd == 2) {
732			checkkwd = 0;
733			while (t == TNL) {
734				parseheredoc();
735				t = xxreadtoken();
736			}
737		} else
738			checkkwd = 0;
739		/*
740		 * check for keywords and aliases
741		 */
742		if (t == TWORD && !quoteflag)
743		{
744			const char * const *pp;
745
746			for (pp = parsekwd; *pp; pp++) {
747				if (**pp == *wordtext && equal(*pp, wordtext))
748				{
749					lasttoken = t = pp - parsekwd + KWDOFFSET;
750					TRACE(("keyword %s recognized\n", tokname[t]));
751					goto out;
752				}
753			}
754			if (noaliases == 0 &&
755			    (ap = lookupalias(wordtext, 1)) != NULL) {
756				pushstring(ap->val, strlen(ap->val), ap);
757				checkkwd = savecheckkwd;
758				goto top;
759			}
760		}
761out:
762		checkkwd = (t == TNOT) ? savecheckkwd : 0;
763	}
764#ifdef DEBUG
765	if (!alreadyseen)
766	    TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
767	else
768	    TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
769#endif
770	return (t);
771}
772
773
774/*
775 * Read the next input token.
776 * If the token is a word, we set backquotelist to the list of cmds in
777 *	backquotes.  We set quoteflag to true if any part of the word was
778 *	quoted.
779 * If the token is TREDIR, then we set redirnode to a structure containing
780 *	the redirection.
781 * In all cases, the variable startlinno is set to the number of the line
782 *	on which the token starts.
783 *
784 * [Change comment:  here documents and internal procedures]
785 * [Readtoken shouldn't have any arguments.  Perhaps we should make the
786 *  word parsing code into a separate routine.  In this case, readtoken
787 *  doesn't need to have any internal procedures, but parseword does.
788 *  We could also make parseoperator in essence the main routine, and
789 *  have parseword (readtoken1?) handle both words and redirection.]
790 */
791
792#define RETURN(token)	return lasttoken = token
793
794STATIC int
795xxreadtoken(void)
796{
797	int c;
798
799	if (tokpushback) {
800		tokpushback = 0;
801		return lasttoken;
802	}
803	if (needprompt) {
804		setprompt(2);
805		needprompt = 0;
806	}
807	startlinno = plinno;
808	for (;;) {	/* until token or start of word found */
809		c = pgetc_macro();
810		if (c == ' ' || c == '\t')
811			continue;		/* quick check for white space first */
812		switch (c) {
813		case ' ': case '\t':
814			continue;
815		case '#':
816			while ((c = pgetc()) != '\n' && c != PEOF);
817			pungetc();
818			continue;
819		case '\\':
820			if (pgetc() == '\n') {
821				startlinno = ++plinno;
822				if (doprompt)
823					setprompt(2);
824				else
825					setprompt(0);
826				continue;
827			}
828			pungetc();
829			goto breakloop;
830		case '\n':
831			plinno++;
832			needprompt = doprompt;
833			RETURN(TNL);
834		case PEOF:
835			RETURN(TEOF);
836		case '&':
837			if (pgetc() == '&')
838				RETURN(TAND);
839			pungetc();
840			RETURN(TBACKGND);
841		case '|':
842			if (pgetc() == '|')
843				RETURN(TOR);
844			pungetc();
845			RETURN(TPIPE);
846		case ';':
847			if (pgetc() == ';')
848				RETURN(TENDCASE);
849			pungetc();
850			RETURN(TSEMI);
851		case '(':
852			RETURN(TLP);
853		case ')':
854			RETURN(TRP);
855		default:
856			goto breakloop;
857		}
858	}
859breakloop:
860	return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
861#undef RETURN
862}
863
864
865
866/*
867 * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
868 * is not NULL, read a here document.  In the latter case, eofmark is the
869 * word which marks the end of the document and striptabs is true if
870 * leading tabs should be stripped from the document.  The argument firstc
871 * is the first character of the input token or document.
872 *
873 * Because C does not have internal subroutines, I have simulated them
874 * using goto's to implement the subroutine linkage.  The following macros
875 * will run code that appears at the end of readtoken1.
876 */
877
878#define CHECKEND()	{goto checkend; checkend_return:;}
879#define PARSEREDIR()	{goto parseredir; parseredir_return:;}
880#define PARSESUB()	{goto parsesub; parsesub_return:;}
881#define PARSEBACKQOLD()	{oldstyle = 1; goto parsebackq; parsebackq_oldreturn:;}
882#define PARSEBACKQNEW()	{oldstyle = 0; goto parsebackq; parsebackq_newreturn:;}
883#define	PARSEARITH()	{goto parsearith; parsearith_return:;}
884
885STATIC int
886readtoken1(int firstc, char const *syntax, char *eofmark, int striptabs)
887{
888	int c = firstc;
889	char *out;
890	int len;
891	char line[EOFMARKLEN + 1];
892	struct nodelist *bqlist;
893	int quotef;
894	int dblquote;
895	int varnest;	/* levels of variables expansion */
896	int arinest;	/* levels of arithmetic expansion */
897	int parenlevel;	/* levels of parens in arithmetic */
898	int oldstyle;
899	char const *prevsyntax;	/* syntax before arithmetic */
900	int synentry;
901#ifdef __GNUC__
902	/* Avoid longjmp clobbering */
903	(void) &out;
904	(void) &quotef;
905	(void) &dblquote;
906	(void) &varnest;
907	(void) &arinest;
908	(void) &parenlevel;
909	(void) &oldstyle;
910	(void) &prevsyntax;
911	(void) &syntax;
912	(void) &synentry;
913#endif
914
915	startlinno = plinno;
916	dblquote = 0;
917	if (syntax == DQSYNTAX)
918		dblquote = 1;
919	quotef = 0;
920	bqlist = NULL;
921	varnest = 0;
922	arinest = 0;
923	parenlevel = 0;
924
925	STARTSTACKSTR(out);
926	loop: {	/* for each line, until end of word */
927		CHECKEND();	/* set c to PEOF if at end of here document */
928		for (;;) {	/* until end of line or end of word */
929			CHECKSTRSPACE(3, out);	/* permit 3 calls to USTPUTC */
930
931			synentry = syntax[c];
932
933			switch(synentry) {
934			case CNL:	/* '\n' */
935				if (syntax == BASESYNTAX)
936					goto endword;	/* exit outer loop */
937				USTPUTC(c, out);
938				plinno++;
939				if (doprompt)
940					setprompt(2);
941				else
942					setprompt(0);
943				c = pgetc();
944				goto loop;		/* continue outer loop */
945			case CWORD:
946				USTPUTC(c, out);
947				break;
948			case CCTL:
949				if (eofmark == NULL || dblquote)
950					USTPUTC(CTLESC, out);
951				USTPUTC(c, out);
952				break;
953			case CBACK:	/* backslash */
954				c = pgetc();
955				if (c == PEOF) {
956					USTPUTC('\\', out);
957					pungetc();
958				} else if (c == '\n') {
959					plinno++;
960					if (doprompt)
961						setprompt(2);
962					else
963						setprompt(0);
964				} else {
965					if (dblquote && c != '\\' &&
966					    c != '`' && c != '$' &&
967					    (c != '"' || eofmark != NULL))
968						USTPUTC('\\', out);
969					if (SQSYNTAX[c] == CCTL)
970						USTPUTC(CTLESC, out);
971					else if (eofmark == NULL)
972						USTPUTC(CTLQUOTEMARK, out);
973					USTPUTC(c, out);
974					quotef++;
975				}
976				break;
977			case CSQUOTE:
978				if (eofmark == NULL)
979					USTPUTC(CTLQUOTEMARK, out);
980				syntax = SQSYNTAX;
981				break;
982			case CDQUOTE:
983				if (eofmark == NULL)
984					USTPUTC(CTLQUOTEMARK, out);
985				syntax = DQSYNTAX;
986				dblquote = 1;
987				break;
988			case CENDQUOTE:
989				if (eofmark != NULL && arinest == 0 &&
990				    varnest == 0) {
991					USTPUTC(c, out);
992				} else {
993					if (arinest) {
994						syntax = ARISYNTAX;
995						dblquote = 0;
996					} else if (eofmark == NULL) {
997						syntax = BASESYNTAX;
998						dblquote = 0;
999					}
1000					quotef++;
1001				}
1002				break;
1003			case CVAR:	/* '$' */
1004				PARSESUB();		/* parse substitution */
1005				break;
1006			case CENDVAR:	/* '}' */
1007				if (varnest > 0) {
1008					varnest--;
1009					USTPUTC(CTLENDVAR, out);
1010				} else {
1011					USTPUTC(c, out);
1012				}
1013				break;
1014			case CLP:	/* '(' in arithmetic */
1015				parenlevel++;
1016				USTPUTC(c, out);
1017				break;
1018			case CRP:	/* ')' in arithmetic */
1019				if (parenlevel > 0) {
1020					USTPUTC(c, out);
1021					--parenlevel;
1022				} else {
1023					if (pgetc() == ')') {
1024						if (--arinest == 0) {
1025							USTPUTC(CTLENDARI, out);
1026							syntax = prevsyntax;
1027							if (syntax == DQSYNTAX)
1028								dblquote = 1;
1029							else
1030								dblquote = 0;
1031						} else
1032							USTPUTC(')', out);
1033					} else {
1034						/*
1035						 * unbalanced parens
1036						 *  (don't 2nd guess - no error)
1037						 */
1038						pungetc();
1039						USTPUTC(')', out);
1040					}
1041				}
1042				break;
1043			case CBQUOTE:	/* '`' */
1044				PARSEBACKQOLD();
1045				break;
1046			case CEOF:
1047				goto endword;		/* exit outer loop */
1048			default:
1049				if (varnest == 0)
1050					goto endword;	/* exit outer loop */
1051				USTPUTC(c, out);
1052			}
1053			c = pgetc_macro();
1054		}
1055	}
1056endword:
1057	if (syntax == ARISYNTAX)
1058		synerror("Missing '))'");
1059	if (syntax != BASESYNTAX && ! parsebackquote && eofmark == NULL)
1060		synerror("Unterminated quoted string");
1061	if (varnest != 0) {
1062		startlinno = plinno;
1063		synerror("Missing '}'");
1064	}
1065	USTPUTC('\0', out);
1066	len = out - stackblock();
1067	out = stackblock();
1068	if (eofmark == NULL) {
1069		if ((c == '>' || c == '<')
1070		 && quotef == 0
1071		 && len <= 2
1072		 && (*out == '\0' || is_digit(*out))) {
1073			PARSEREDIR();
1074			return lasttoken = TREDIR;
1075		} else {
1076			pungetc();
1077		}
1078	}
1079	quoteflag = quotef;
1080	backquotelist = bqlist;
1081	grabstackblock(len);
1082	wordtext = out;
1083	return lasttoken = TWORD;
1084/* end of readtoken routine */
1085
1086
1087
1088/*
1089 * Check to see whether we are at the end of the here document.  When this
1090 * is called, c is set to the first character of the next input line.  If
1091 * we are at the end of the here document, this routine sets the c to PEOF.
1092 */
1093
1094checkend: {
1095	if (eofmark) {
1096		if (striptabs) {
1097			while (c == '\t')
1098				c = pgetc();
1099		}
1100		if (c == *eofmark) {
1101			if (pfgets(line, sizeof line) != NULL) {
1102				char *p, *q;
1103
1104				p = line;
1105				for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1106				if (*p == '\n' && *q == '\0') {
1107					c = PEOF;
1108					plinno++;
1109					needprompt = doprompt;
1110				} else {
1111					pushstring(line, strlen(line), NULL);
1112				}
1113			}
1114		}
1115	}
1116	goto checkend_return;
1117}
1118
1119
1120/*
1121 * Parse a redirection operator.  The variable "out" points to a string
1122 * specifying the fd to be redirected.  The variable "c" contains the
1123 * first character of the redirection operator.
1124 */
1125
1126parseredir: {
1127	char fd = *out;
1128	union node *np;
1129
1130	np = (union node *)stalloc(sizeof (struct nfile));
1131	if (c == '>') {
1132		np->nfile.fd = 1;
1133		c = pgetc();
1134		if (c == '>')
1135			np->type = NAPPEND;
1136		else if (c == '&')
1137			np->type = NTOFD;
1138		else if (c == '|')
1139			np->type = NCLOBBER;
1140		else {
1141			np->type = NTO;
1142			pungetc();
1143		}
1144	} else {	/* c == '<' */
1145		np->nfile.fd = 0;
1146		c = pgetc();
1147		if (c == '<') {
1148			if (sizeof (struct nfile) != sizeof (struct nhere)) {
1149				np = (union node *)stalloc(sizeof (struct nhere));
1150				np->nfile.fd = 0;
1151			}
1152			np->type = NHERE;
1153			heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1154			heredoc->here = np;
1155			if ((c = pgetc()) == '-') {
1156				heredoc->striptabs = 1;
1157			} else {
1158				heredoc->striptabs = 0;
1159				pungetc();
1160			}
1161		} else if (c == '&')
1162			np->type = NFROMFD;
1163		else if (c == '>')
1164			np->type = NFROMTO;
1165		else {
1166			np->type = NFROM;
1167			pungetc();
1168		}
1169	}
1170	if (fd != '\0')
1171		np->nfile.fd = digit_val(fd);
1172	redirnode = np;
1173	goto parseredir_return;
1174}
1175
1176
1177/*
1178 * Parse a substitution.  At this point, we have read the dollar sign
1179 * and nothing else.
1180 */
1181
1182parsesub: {
1183	char buf[10];
1184	int subtype;
1185	int typeloc;
1186	int flags;
1187	char *p;
1188	static const char types[] = "}-+?=";
1189	int bracketed_name = 0; /* used to handle ${[0-9]*} variables */
1190	int i;
1191	int linno;
1192	int length;
1193
1194	c = pgetc();
1195	if (c != '(' && c != '{' && (is_eof(c) || !is_name(c)) &&
1196	    !is_special(c)) {
1197		USTPUTC('$', out);
1198		pungetc();
1199	} else if (c == '(') {	/* $(command) or $((arith)) */
1200		if (pgetc() == '(') {
1201			PARSEARITH();
1202		} else {
1203			pungetc();
1204			PARSEBACKQNEW();
1205		}
1206	} else {
1207		USTPUTC(CTLVAR, out);
1208		typeloc = out - stackblock();
1209		USTPUTC(VSNORMAL, out);
1210		subtype = VSNORMAL;
1211		flags = 0;
1212		if (c == '{') {
1213			bracketed_name = 1;
1214			c = pgetc();
1215			if (c == '#') {
1216				if ((c = pgetc()) == '}')
1217					c = '#';
1218				else
1219					subtype = VSLENGTH;
1220			}
1221			else
1222				subtype = 0;
1223		}
1224		if (!is_eof(c) && is_name(c)) {
1225			length = 0;
1226			do {
1227				STPUTC(c, out);
1228				c = pgetc();
1229				length++;
1230			} while (!is_eof(c) && is_in_name(c));
1231			if (length == 6 &&
1232			    strncmp(out - length, "LINENO", length) == 0) {
1233				/* Replace the variable name with the
1234				 * current line number. */
1235				linno = plinno;
1236				if (funclinno != 0)
1237					linno -= funclinno - 1;
1238				snprintf(buf, sizeof(buf), "%d", linno);
1239				STADJUST(-6, out);
1240				for (i = 0; buf[i] != '\0'; i++)
1241					STPUTC(buf[i], out);
1242				flags |= VSLINENO;
1243			}
1244		} else if (is_digit(c)) {
1245			if (bracketed_name) {
1246				do {
1247					STPUTC(c, out);
1248					c = pgetc();
1249				} while (is_digit(c));
1250			} else {
1251				STPUTC(c, out);
1252				c = pgetc();
1253			}
1254		} else {
1255			if (! is_special(c)) {
1256				subtype = VSERROR;
1257				if (c == '}')
1258					pungetc();
1259				else
1260					USTPUTC(c, out);
1261			} else {
1262				USTPUTC(c, out);
1263				c = pgetc();
1264			}
1265		}
1266		if (subtype == 0) {
1267			switch (c) {
1268			case ':':
1269				flags |= VSNUL;
1270				c = pgetc();
1271				/*FALLTHROUGH*/
1272			default:
1273				p = strchr(types, c);
1274				if (p == NULL) {
1275					if (flags == VSNUL)
1276						STPUTC(':', out);
1277					STPUTC(c, out);
1278					subtype = VSERROR;
1279				} else
1280					subtype = p - types + VSNORMAL;
1281				break;
1282			case '%':
1283			case '#':
1284				{
1285					int cc = c;
1286					subtype = c == '#' ? VSTRIMLEFT :
1287							     VSTRIMRIGHT;
1288					c = pgetc();
1289					if (c == cc)
1290						subtype++;
1291					else
1292						pungetc();
1293					break;
1294				}
1295			}
1296		} else if (subtype != VSERROR) {
1297			pungetc();
1298		}
1299		STPUTC('=', out);
1300		if (subtype != VSLENGTH && (dblquote || arinest))
1301			flags |= VSQUOTE;
1302		*(stackblock() + typeloc) = subtype | flags;
1303		if (subtype != VSNORMAL)
1304			varnest++;
1305	}
1306	goto parsesub_return;
1307}
1308
1309
1310/*
1311 * Called to parse command substitutions.  Newstyle is set if the command
1312 * is enclosed inside $(...); nlpp is a pointer to the head of the linked
1313 * list of commands (passed by reference), and savelen is the number of
1314 * characters on the top of the stack which must be preserved.
1315 */
1316
1317parsebackq: {
1318	struct nodelist **nlpp;
1319	int savepbq;
1320	union node *n;
1321	char *volatile str;
1322	struct jmploc jmploc;
1323	struct jmploc *volatile savehandler;
1324	int savelen;
1325	int saveprompt;
1326#ifdef __GNUC__
1327	/* Avoid longjmp clobbering */
1328	(void) &saveprompt;
1329#endif
1330
1331	savepbq = parsebackquote;
1332	if (setjmp(jmploc.loc)) {
1333		if (str)
1334			ckfree(str);
1335		parsebackquote = 0;
1336		handler = savehandler;
1337		longjmp(handler->loc, 1);
1338	}
1339	INTOFF;
1340	str = NULL;
1341	savelen = out - stackblock();
1342	if (savelen > 0) {
1343		str = ckmalloc(savelen);
1344		memcpy(str, stackblock(), savelen);
1345	}
1346	savehandler = handler;
1347	handler = &jmploc;
1348	INTON;
1349        if (oldstyle) {
1350                /* We must read until the closing backquote, giving special
1351                   treatment to some slashes, and then push the string and
1352                   reread it as input, interpreting it normally.  */
1353                char *out;
1354                int c;
1355                int savelen;
1356                char *str;
1357
1358
1359                STARTSTACKSTR(out);
1360		for (;;) {
1361			if (needprompt) {
1362				setprompt(2);
1363				needprompt = 0;
1364			}
1365			switch (c = pgetc()) {
1366			case '`':
1367				goto done;
1368
1369			case '\\':
1370                                if ((c = pgetc()) == '\n') {
1371					plinno++;
1372					if (doprompt)
1373						setprompt(2);
1374					else
1375						setprompt(0);
1376					/*
1377					 * If eating a newline, avoid putting
1378					 * the newline into the new character
1379					 * stream (via the STPUTC after the
1380					 * switch).
1381					 */
1382					continue;
1383				}
1384                                if (c != '\\' && c != '`' && c != '$'
1385                                    && (!dblquote || c != '"'))
1386                                        STPUTC('\\', out);
1387				break;
1388
1389			case '\n':
1390				plinno++;
1391				needprompt = doprompt;
1392				break;
1393
1394			case PEOF:
1395			        startlinno = plinno;
1396				synerror("EOF in backquote substitution");
1397 				break;
1398
1399			default:
1400				break;
1401			}
1402			STPUTC(c, out);
1403                }
1404done:
1405                STPUTC('\0', out);
1406                savelen = out - stackblock();
1407                if (savelen > 0) {
1408                        str = ckmalloc(savelen);
1409                        memcpy(str, stackblock(), savelen);
1410			setinputstring(str, 1);
1411                }
1412        }
1413	nlpp = &bqlist;
1414	while (*nlpp)
1415		nlpp = &(*nlpp)->next;
1416	*nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1417	(*nlpp)->next = NULL;
1418	parsebackquote = oldstyle;
1419
1420	if (oldstyle) {
1421		saveprompt = doprompt;
1422		doprompt = 0;
1423	}
1424
1425	n = list(0);
1426
1427	if (oldstyle)
1428		doprompt = saveprompt;
1429	else {
1430		if (readtoken() != TRP)
1431			synexpect(TRP);
1432	}
1433
1434	(*nlpp)->n = n;
1435        if (oldstyle) {
1436		/*
1437		 * Start reading from old file again, ignoring any pushed back
1438		 * tokens left from the backquote parsing
1439		 */
1440                popfile();
1441		tokpushback = 0;
1442	}
1443	while (stackblocksize() <= savelen)
1444		growstackblock();
1445	STARTSTACKSTR(out);
1446	if (str) {
1447		memcpy(out, str, savelen);
1448		STADJUST(savelen, out);
1449		INTOFF;
1450		ckfree(str);
1451		str = NULL;
1452		INTON;
1453	}
1454	parsebackquote = savepbq;
1455	handler = savehandler;
1456	if (arinest || dblquote)
1457		USTPUTC(CTLBACKQ | CTLQUOTE, out);
1458	else
1459		USTPUTC(CTLBACKQ, out);
1460	if (oldstyle)
1461		goto parsebackq_oldreturn;
1462	else
1463		goto parsebackq_newreturn;
1464}
1465
1466/*
1467 * Parse an arithmetic expansion (indicate start of one and set state)
1468 */
1469parsearith: {
1470
1471	if (++arinest == 1) {
1472		prevsyntax = syntax;
1473		syntax = ARISYNTAX;
1474		USTPUTC(CTLARI, out);
1475		if (dblquote)
1476			USTPUTC('"',out);
1477		else
1478			USTPUTC(' ',out);
1479	} else {
1480		/*
1481		 * we collapse embedded arithmetic expansion to
1482		 * parenthesis, which should be equivalent
1483		 */
1484		USTPUTC('(', out);
1485	}
1486	goto parsearith_return;
1487}
1488
1489} /* end of readtoken */
1490
1491
1492
1493#ifdef mkinit
1494RESET {
1495	tokpushback = 0;
1496	checkkwd = 0;
1497}
1498#endif
1499
1500/*
1501 * Returns true if the text contains nothing to expand (no dollar signs
1502 * or backquotes).
1503 */
1504
1505STATIC int
1506noexpand(char *text)
1507{
1508	char *p;
1509	char c;
1510
1511	p = text;
1512	while ((c = *p++) != '\0') {
1513		if ( c == CTLQUOTEMARK)
1514			continue;
1515		if (c == CTLESC)
1516			p++;
1517		else if (BASESYNTAX[(int)c] == CCTL)
1518			return 0;
1519	}
1520	return 1;
1521}
1522
1523
1524/*
1525 * Return true if the argument is a legal variable name (a letter or
1526 * underscore followed by zero or more letters, underscores, and digits).
1527 */
1528
1529int
1530goodname(char *name)
1531{
1532	char *p;
1533
1534	p = name;
1535	if (! is_name(*p))
1536		return 0;
1537	while (*++p) {
1538		if (! is_in_name(*p))
1539			return 0;
1540	}
1541	return 1;
1542}
1543
1544
1545/*
1546 * Called when an unexpected token is read during the parse.  The argument
1547 * is the token that is expected, or -1 if more than one type of token can
1548 * occur at this point.
1549 */
1550
1551STATIC void
1552synexpect(int token)
1553{
1554	char msg[64];
1555
1556	if (token >= 0) {
1557		fmtstr(msg, 64, "%s unexpected (expecting %s)",
1558			tokname[lasttoken], tokname[token]);
1559	} else {
1560		fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1561	}
1562	synerror(msg);
1563}
1564
1565
1566STATIC void
1567synerror(char *msg)
1568{
1569	if (commandname)
1570		outfmt(&errout, "%s: %d: ", commandname, startlinno);
1571	outfmt(&errout, "Syntax error: %s\n", msg);
1572	error((char *)NULL);
1573}
1574
1575STATIC void
1576setprompt(int which)
1577{
1578	whichprompt = which;
1579
1580#ifndef NO_HISTORY
1581	if (!el)
1582#endif
1583		out2str(getprompt(NULL));
1584}
1585
1586/*
1587 * called by editline -- any expansions to the prompt
1588 *    should be added here.
1589 */
1590char *
1591getprompt(void *unused __unused)
1592{
1593	static char ps[PROMPTLEN];
1594	char *fmt;
1595	int i, j, trim;
1596
1597	/*
1598	 * Select prompt format.
1599	 */
1600	switch (whichprompt) {
1601	case 0:
1602		fmt = "";
1603		break;
1604	case 1:
1605		fmt = ps1val();
1606		break;
1607	case 2:
1608		fmt = ps2val();
1609		break;
1610	default:
1611		return "<internal prompt error>";
1612	}
1613
1614	/*
1615	 * Format prompt string.
1616	 */
1617	for (i = 0; (i < 127) && (*fmt != '\0'); i++, fmt++)
1618		if (*fmt == '\\')
1619			switch (*++fmt) {
1620
1621				/*
1622				 * Hostname.
1623				 *
1624				 * \h specifies just the local hostname,
1625				 * \H specifies fully-qualified hostname.
1626				 */
1627			case 'h':
1628			case 'H':
1629				ps[i] = '\0';
1630				gethostname(&ps[i], PROMPTLEN - i);
1631				/* Skip to end of hostname. */
1632				trim = (*fmt == 'h') ? '.' : '\0';
1633				while ((ps[i+1] != '\0') && (ps[i+1] != trim))
1634					i++;
1635				break;
1636
1637				/*
1638				 * Working directory.
1639				 *
1640				 * \W specifies just the final component,
1641				 * \w specifies the entire path.
1642				 */
1643			case 'W':
1644			case 'w':
1645				ps[i] = '\0';
1646				getcwd(&ps[i], PROMPTLEN - i);
1647				if (*fmt == 'W') {
1648					/* Final path component only. */
1649					trim = 1;
1650					for (j = i; ps[j] != '\0'; j++)
1651					  if (ps[j] == '/')
1652						trim = j + 1;
1653					memmove(&ps[i], &ps[trim],
1654					    j - trim + 1);
1655				}
1656				/* Skip to end of path. */
1657				while (ps[i + 1] != '\0')
1658					i++;
1659				break;
1660
1661				/*
1662				 * Superuser status.
1663				 *
1664				 * '$' for normal users, '#' for root.
1665				 */
1666			case '$':
1667				ps[i] = (geteuid() != 0) ? '$' : '#';
1668				break;
1669
1670				/*
1671				 * A literal \.
1672				 */
1673			case '\\':
1674				ps[i] = '\\';
1675				break;
1676
1677				/*
1678				 * Emit unrecognized formats verbatim.
1679				 */
1680			default:
1681				ps[i++] = '\\';
1682				ps[i] = *fmt;
1683				break;
1684			}
1685		else
1686			ps[i] = *fmt;
1687	ps[i] = '\0';
1688	return (ps);
1689}
1690