#/* * UNIX shell * * S. R. Bourne * Bell Telephone Laboratories * */#include	"defs.h"PROC BOOL	chkid();NAMNOD	ps2nod	= {	NIL,		NIL,		ps2name},	fngnod	= {	NIL,		NIL,		fngname},	pathnod = {	NIL,		NIL,		pathname},	ifsnod	= {	NIL,		NIL,		ifsname},	ps1nod	= {	&pathnod,	&ps2nod,	ps1name},	homenod = {	&fngnod,	&ifsnod,	homename},	mailnod = {	&homenod,	&ps1nod,	mailname};NAMPTR		namep = &mailnod;/* ========	variable and string handling	======== */syslook(w,syswds)	STRING		w;	SYSTAB		syswds;{	REG CHAR	first;	REG STRING	s;	REG SYSPTR	syscan;	syscan=syswds; first = *w;	WHILE s=syscan->sysnam	DO  IF first == *s		ANDF eq(w,s)	    THEN return(syscan->sysval);	    FI	    syscan++;	OD	return(0);}setlist(arg,xp)	REG ARGPTR	arg;	INT		xp;{	WHILE arg	DO REG STRING	s=mactrim(arg->argval);	   setname(s, xp);	   arg=arg->argnxt;	   IF flags&execpr	   THEN prs(s);		IF arg THEN blank(); ELSE newline(); FI	   FI	OD}VOID	setname(argi, xp)	STRING		argi;	INT		xp;{	REG STRING	argscan=argi;	REG NAMPTR	n;	IF letter(*argscan)	THEN	WHILE alphanum(*argscan) DO argscan++ OD		IF *argscan=='='		THEN	*argscan = 0;			n=lookup(argi);			*argscan++ = '=';			attrib(n, xp);			IF xp&N_ENVNAM			THEN	n->namenv = n->namval = argscan;			ELSE	assign(n, argscan);			FI			return;		FI	FI	failed(argi,notid);}replace(a, v)	REG STRING	*a;	STRING		v;{	free(*a); *a=make(v);}dfault(n,v)	NAMPTR		n;	STRING		v;{	IF n->namval==0	THEN	assign(n,v)	FI}assign(n,v)	NAMPTR		n;	STRING		v;{	IF n->namflg&N_RDONLY	THEN	failed(n->namid,wtfailed);	ELSE	replace(&n->namval,v);	FI}INT	readvar(names)	STRING		*names;{	FILEBLK		fb;	REG FILE	f = &fb;	REG CHAR	c;	REG INT		rc=0;	NAMPTR		n=lookup(*names++); /* done now to avoid storage mess */	STKPTR		rel=relstak();	push(f); initf(dup(0));	IF lseek(0,0L,1)==-1	THEN	f->fsiz=1;	FI	LOOP	c=nextc(0);		IF (*names ANDF any(c, ifsnod.namval)) ORF eolchar(c)		THEN	zerostak();			assign(n,absstak(rel)); setstak(rel);			IF *names			THEN	n=lookup(*names++);			ELSE	n=0;			FI			IF eolchar(c)			THEN	break;			FI		ELSE	pushstak(c);		FI	POOL	WHILE n	DO assign(n, nullstr);	   IF *names THEN n=lookup(*names++); ELSE n=0; FI	OD	IF eof THEN rc=1 FI	lseek(0, (long)(f->fnxt-f->fend), 1);	pop();	return(rc);}assnum(p, i)	STRING		*p;	INT		i;{	itos(i); replace(p,numbuf);}STRING	make(v)	STRING		v;{	REG STRING	p;	IF v	THEN	movstr(v,p=alloc(length(v)));		return(p);	ELSE	return(0);	FI}NAMPTR		lookup(nam)	REG STRING	nam;{	REG NAMPTR	nscan=namep;	REG NAMPTR	*prev;	INT		LR;	IF !chkid(nam)	THEN	failed(nam,notid);	FI	WHILE nscan	DO	IF (LR=cf(nam,nscan->namid))==0		THEN	return(nscan);		ELIF LR<0		THEN	prev = &(nscan->namlft);		ELSE	prev = &(nscan->namrgt);		FI		nscan = *prev;	OD	/* add name node */	nscan=alloc(sizeof *nscan);	nscan->namlft=nscan->namrgt=NIL;	nscan->namid=make(nam);	nscan->namval=0; nscan->namflg=N_DEFAULT; nscan->namenv=0;	return(*prev = nscan);}LOCAL BOOL	chkid(nam)	STRING		nam;{	REG CHAR *	cp=nam;	IF !letter(*cp)	THEN	return(FALSE);	ELSE	WHILE *++cp		DO IF !alphanum(*cp)		   THEN	return(FALSE);		   FI		OD	FI	return(TRUE);}LOCAL VOID (*namfn)();namscan(fn)	VOID		(*fn)();{	namfn=fn;	namwalk(namep);}LOCAL VOID	namwalk(np)	REG NAMPTR	np;{	IF np	THEN	namwalk(np->namlft);		(*namfn)(np);		namwalk(np->namrgt);	FI}VOID	printnam(n)	NAMPTR		n;{	REG STRING	s;	sigchk();	IF s=n->namval	THEN	prs(n->namid);		prc('='); prs(s);		newline();	FI}LOCAL STRING	staknam(n)	REG NAMPTR	n;{	REG STRING	p;	p=movstr(n->namid,staktop);	p=movstr("=",p);	p=movstr(n->namval,p);	return(getstak(p+1-ADR(stakbot)));}VOID	exname(n)	REG NAMPTR	n;{	IF n->namflg&N_EXPORT	THEN	free(n->namenv);		n->namenv = make(n->namval);	ELSE	free(n->namval);		n->namval = make(n->namenv);	FI}VOID	printflg(n)	REG NAMPTR		n;{	IF n->namflg&N_EXPORT	THEN	prs(export); blank();	FI	IF n->namflg&N_RDONLY	THEN	prs(readonly); blank();	FI	IF n->namflg&(N_EXPORT|N_RDONLY)	THEN	prs(n->namid); newline();	FI}VOID	getenv(){	REG STRING	*e=environ;	WHILE *e	DO setname(*e++, N_ENVNAM) OD}LOCAL INT	namec;VOID	countnam(n)	NAMPTR		n;{	namec++;}LOCAL STRING 	*argnam;VOID	pushnam(n)	NAMPTR		n;{	IF n->namval	THEN	*argnam++ = staknam(n);	FI}STRING	*setenv(){	REG STRING	*er;	namec=0;	namscan(countnam);	argnam = er = getstak(namec*BYTESPERWORD+BYTESPERWORD);	namscan(pushnam);	*argnam++ = 0;	return(er);}