[unix-history] / usr / src / old / sh / xec.c

#ifndef lint
static char sccsid[] = "@(#)xec.c	4.6 %G%";
#endif

#
/*
 * UNIX shell
 *
 * S. R. Bourne
 * Bell Telephone Laboratories
 *
 */

#include	"defs.h"
#include	"sym.h"

LOCAL INT	parent;

SYSTAB		commands;


/* ========	command execution	========*/


execute(argt, execflg, pf1, pf2)
	TREPTR		argt;
	INT		*pf1, *pf2;
{
	/* `stakbot' is preserved by this routine */
	REG TREPTR	t;
	STKPTR		sav=savstak();

	sigchk();

	IF (t=argt) ANDF execbrk==0
	THEN	REG INT		treeflgs;
		INT		oldexit, type;
		REG STRING	*com;

		treeflgs = t->tretyp; type = treeflgs&COMMSK;
		oldexit=exitval; exitval=0;

		SWITCH type IN

		case TCOM:
			BEGIN
			STRING		a1;
			INT		argn, internal;
			ARGPTR		schain=gchain;
			IOPTR		io=t->treio.treio;
			gchain=0;
			argn = getarg(t);
			com=scan(argn);
			a1=com[1]; gchain=schain;

			IF argn==0 ORF (internal=syslook(com[0],commands))
			THEN	setlist(t->comnod.comset, 0);
			FI

			IF argn ANDF (flags&noexec)==0
			THEN	/* print command if execpr */
				IF flags&execpr
				THEN	argn=0;	prs(execpmsg);
					WHILE com[argn]!=ENDARGS
					DO prs(com[argn++]); blank() OD
					newline();
				FI

				SWITCH internal IN

				case SYSDOT:
					IF a1
					THEN	REG INT		f;
	
						IF (f=pathopen(getpath(a1), a1)) < 0
						THEN failed(a1,notfound);
						ELSE execexp(0,f);
						FI
					FI
					break;
	
				case SYSTIMES:
					{
					L_INT	t[4]; times(t);
					prt(t[2]); blank(); prt(t[3]); newline();
					}
					break;
	
				case SYSEXIT:
					exitsh(a1?stoi(a1):oldexit);
	
				case SYSNULL:
					io=0;
					break;
	
				case SYSCONT:
					execbrk = -loopcnt; break;
	
				case SYSBREAK:
					IF (execbrk=loopcnt) ANDF a1
					THEN breakcnt=stoi(a1);
					FI
					break;
	
				case SYSTRAP:
					IF a1
					THEN	BOOL	clear;
						IF (clear=digit(*a1))==0
						THEN	++com;
						FI
						WHILE *++com
						DO INT	i;
						   IF (i=stoi(*com))>=MAXTRAP ORF i<MINTRAP
						   THEN	failed(*com,badtrap);
						   ELIF clear
						   THEN	clrsig(i);
						   ELSE	replace(&trapcom[i],a1);
							IF *a1
							THEN	getsig(i);
							ELSE	ignsig(i);
							FI
						   FI
						OD
					ELSE	/* print out current traps */
						INT		i;
	
						FOR i=0; i<MAXTRAP; i++
						DO IF trapcom[i]
						   THEN	prn(i); prs(colon); prs(trapcom[i]); newline();
						   FI
						OD
					FI
					break;
	
				case SYSEXEC:
					com++;
					initio(io); ioset=0; io=0;
					IF a1==0 THEN break FI
	
				case SYSLOGIN:
					flags |= forked;
					oldsigs(); execa(com); done();
	
				case SYSCD:
					IF flags&rshflg
					THEN	failed(com[0],restricted);
					ELIF (a1==0 ANDF (a1=homenod.namval)==0) ORF chdir(a1)<0
					THEN	failed(a1,baddir);
					FI
					break;
	
				case SYSSHFT:
					IF dolc<1
					THEN	error(badshift);
					ELSE	dolv++; dolc--;
					FI
					assnum(&dolladr, dolc);
					break;
	
				case SYSWAIT:
					await(-1);
					break;
	
				case SYSREAD:
					exitval=readvar(&com[1]);
					break;

/*
				case SYSTST:
					exitval=testcmd(com);
					break;
*/

				case SYSSET:
					IF a1
					THEN	INT	argc;
						argc = options(argn,com);
						IF argc>1
						THEN	setargs(com+argn-argc);
						FI
					ELIF t->comnod.comset==0
					THEN	/*scan name chain and print*/
						namscan(printnam);
					FI
					break;
	
				case SYSRDONLY:
					exitval=N_RDONLY;
				case SYSXPORT:
					IF exitval==0 THEN exitval=N_EXPORT; FI
	
					IF a1
					THEN	WHILE *++com
						DO attrib(lookup(*com), exitval) OD
					ELSE	namscan(printflg);
					FI
					exitval=0;
					break;
	
				case SYSEVAL:
					IF a1
					THEN	execexp(a1,&com[2]);
					FI
					break;

                                case SYSUMASK:
                                        if (a1) {
                                                int c, i;
                                                i = 0;
                                                while ((c = *a1++) >= '0' &&
                                                        c <= '7')
                                                        i = (i << 3) + c - '0';
                                                umask(i);
                                        } else {
                                                int i, j;
                                                umask(i = umask(0));
                                                prc('0');
                                                for (j = 6; j >= 0; j -= 3)
                                                        prc(((i>>j)&07) + '0');
                                                newline();
                                        }
                                        break;
	
				default:
					internal=builtin(argn,com);
	
				ENDSW

				IF internal
				THEN	IF io THEN error(illegal) FI
					chktrap();
					break;
				FI
			ELIF t->treio.treio==0
			THEN	break;
			FI
			END
	
		case TFORK:
			IF execflg ANDF (treeflgs&(FAMP|FPOU))==0
			THEN	parent=0;
			ELSE	WHILE (parent=fork()) == -1
				DO sigchk(); alarm(10); pause() OD
			FI

			IF parent
			THEN	/* This is the parent branch of fork;    */
				/* it may or may not wait for the child. */
				IF treeflgs&FPRS ANDF flags&ttyflg
				THEN	prn(parent); newline();
				FI
				IF treeflgs&FPCL THEN closepipe(pf1) FI
				IF (treeflgs&(FAMP|FPOU))==0
				THEN	await(parent);
				ELIF (treeflgs&FAMP)==0
				THEN	post(parent);
				ELSE	assnum(&pcsadr, parent);
				FI

				chktrap();
				break;


			ELSE	/* this is the forked branch (child) of execute */
				flags |= forked; iotemp=0;
				postclr();
				settmp();

				/* Turn off INTR and QUIT if `FINT'  */
				/* Reset ramaining signals to parent */
				/* except for those `lost' by trap   */
				oldsigs();
				IF treeflgs&FINT
				THEN	signal(INTR,1); signal(QUIT,1);
				FI

				/* pipe in or out */
				IF treeflgs&FPIN
				THEN	rename(pf1[INPIPE],0);
					close(pf1[OTPIPE]);
				FI
				IF treeflgs&FPOU
				THEN	rename(pf2[OTPIPE],1);
					close(pf2[INPIPE]);
				FI

				/* default std input for & */
				IF treeflgs&FINT ANDF ioset==0
				THEN	rename(chkopen(devnull),0);
				FI

				/* io redirection */
				initio(t->treio.treio);
				IF type!=TCOM
				THEN	execute(t->forknod.forktre,1);
				ELIF com[0]!=ENDARGS
				THEN	setlist(t->comnod.comset,N_EXPORT);
					execa(com);
				FI
				done();
			FI

		case TPAR:
			rename(dup(2),output);
			execute(t->parnod.partre,execflg);
			done();

		case TFIL:
			BEGIN
			   INT pv[2]; chkpipe(pv);
			   IF execute(t->lstnod.lstlef, 0, pf1, pv)==0
			   THEN	execute(t->lstnod.lstrit, execflg, pv, pf2);
			   ELSE	closepipe(pv);
			   FI
			END
			break;

		case TLST:
			execute(t->lstnod.lstlef,0);
			execute(t->lstnod.lstrit,execflg);
			break;

		case TAND:
			IF execute(t->lstnod.lstlef,0)==0
			THEN	execute(t->lstnod.lstrit,execflg);
			FI
			break;

		case TORF:
			IF execute(t->lstnod.lstlef,0)!=0
			THEN	execute(t->lstnod.lstrit,execflg);
			FI
			break;

		case TFOR:
			BEGIN
			   NAMPTR	n = lookup(t->fornod.fornam);
			   STRING	*args;
			   DOLPTR	argsav=0;

			   IF t->fornod.forlst==0
			   THEN    args=dolv+1;
				   argsav=useargs();
			   ELSE	   ARGPTR	schain=gchain;
				   gchain=0;
				   trim((args=scan(getarg(t->fornod.forlst)))[0]);
				   gchain=schain;
			   FI
			   loopcnt++;
			   WHILE *args!=ENDARGS ANDF execbrk==0
			   DO	assign(n,*args++);
				execute(t->fornod.fortre,0);
				IF execbrk<0 THEN execbrk=0 FI
			   OD
			   IF breakcnt THEN breakcnt-- FI
			   execbrk=breakcnt; loopcnt--;
			   argfor=freeargs(argsav);
			END
			break;

		case TWH:
		case TUN:
			BEGIN
			   INT		i=0, saveflg;

			   saveflg = flags&errflg;
			   loopcnt++;
			   WHILE execbrk==0
			   DO flags &= ~errflg;
			      i=execute(t->whnod.whtre,0);
			      flags |= saveflg;
			      IF (i==0)!=(type==TWH) THEN break FI
			      i=execute(t->whnod.dotre,0);
			      IF execbrk<0 THEN execbrk=0 FI
			   OD
			   IF breakcnt THEN breakcnt-- FI
			   execbrk=breakcnt; loopcnt--; exitval=i;
			END
			break;

		case TIF:
			BEGIN
			   INT		i, saveflg;

			   saveflg = flags&errflg;
			   flags &= ~errflg;
			   i=execute(t->ifnod.iftre,0);
			   flags |= saveflg;
			   IF i==0
			   THEN	execute(t->ifnod.thtre,execflg);
			   ELSE	execute(t->ifnod.eltre,execflg);
			   FI
			END
			break;

		case TSW:
			BEGIN
			   REG STRING	r = mactrim(t->swnod.swarg);
			   REG REGPTR	eg = t->swnod.swlst;
			   WHILE eg
			   DO	ARGPTR		rex=eg->regptr;
				WHILE rex
				DO	REG STRING	s;
					IF gmatch(r,s=macro(rex->argval)) ORF (trim(s), eq(r,s))
					THEN	execute(eg->regcom,0);
						eg=0; break;
					ELSE	rex=rex->argnxt;
					FI
				OD
				IF eg THEN eg=eg->regnxt FI
			   OD
			END
			break;
		ENDSW
		exitset();
	FI

	sigchk();
	tdystak(sav);
	return(exitval);
}


execexp(s,f)
	STRING		s;
	UFD		f;
{
	FILEBLK		fb;
	push(&fb);
	IF s
	THEN	estabf(s); fb.feval=f;
	ELIF f>=0
	THEN	initf(f);
	FI
	execute(cmd(NL, NLFLG|MTFLG),0);
	pop();
}
Commit	Line	Data
f6227721	1	#ifndef lint
3cc4dafe	2	static char sccsid[] = "@(#)xec.c 4.6 %G%";
f6227721	3	#endif
f8e636e7 KM	4
	5	#
	6	/*
	7	* UNIX shell
	8	*
	9	* S. R. Bourne
	10	* Bell Telephone Laboratories
	11	*
	12	*/
	13
	14	#include "defs.h"
	15	#include "sym.h"
	16
	17	LOCAL INT parent;
	18
	19	SYSTAB commands;
	20
	21
	22
	23	/* ======== command execution ========*/
	24
	25
	26	execute(argt, execflg, pf1, pf2)
	27	TREPTR argt;
	28	INT pf1, pf2;
	29	{
	30	/* `stakbot' is preserved by this routine */
	31	REG TREPTR t;
	32	STKPTR sav=savstak();
	33
	34	sigchk();
	35
	36	IF (t=argt) ANDF execbrk==0
	37	THEN REG INT treeflgs;
	38	INT oldexit, type;
	39	REG STRING *com;
	40
	41	treeflgs = t->tretyp; type = treeflgs&COMMSK;
	42	oldexit=exitval; exitval=0;
	43
	44	SWITCH type IN
	45
	46	case TCOM:
	47	BEGIN
	48	STRING a1;
	49	INT argn, internal;
	50	ARGPTR schain=gchain;
3cc4dafe	51	IOPTR io=t->treio.treio;
f8e636e7 KM	52	gchain=0;
	53	argn = getarg(t);
	54	com=scan(argn);
	55	a1=com[1]; gchain=schain;
	56
eb594574	57	IF argn==0 ORF (internal=syslook(com[0],commands))
3cc4dafe	58	THEN setlist(t->comnod.comset, 0);
f8e636e7 KM	59	FI
	60
	61	IF argn ANDF (flags&noexec)==0
	62	THEN /* print command if execpr */
	63	IF flags&execpr
	64	THEN argn=0; prs(execpmsg);
	65	WHILE com[argn]!=ENDARGS
	66	DO prs(com[argn++]); blank() OD
	67	newline();
	68	FI
	69
	70	SWITCH internal IN
	71
	72	case SYSDOT:
	73	IF a1
	74	THEN REG INT f;
	75
	76	IF (f=pathopen(getpath(a1), a1)) < 0
	77	THEN failed(a1,notfound);
	78	ELSE execexp(0,f);
	79	FI
	80	FI
	81	break;
	82
	83	case SYSTIMES:
	84	{
	85	L_INT t[4]; times(t);
	86	prt(t[2]); blank(); prt(t[3]); newline();
	87	}
	88	break;
	89
	90	case SYSEXIT:
	91	exitsh(a1?stoi(a1):oldexit);
	92
	93	case SYSNULL:
	94	io=0;
	95	break;
	96
	97	case SYSCONT:
	98	execbrk = -loopcnt; break;
	99
	100	case SYSBREAK:
	101	IF (execbrk=loopcnt) ANDF a1
	102	THEN breakcnt=stoi(a1);
	103	FI
	104	break;
	105
	106	case SYSTRAP:
	107	IF a1
	108	THEN BOOL clear;
	109	IF (clear=digit(*a1))==0
	110	THEN ++com;
	111	FI
	112	WHILE *++com
	113	DO INT i;
	114	IF (i=stoi(*com))>=MAXTRAP ORF i<MINTRAP
	115	THEN failed(*com,badtrap);
	116	ELIF clear
	117	THEN clrsig(i);
	118	ELSE replace(&trapcom[i],a1);
	119	IF *a1
	120	THEN getsig(i);
	121	ELSE ignsig(i);
	122	FI
123	FI
124	OD
125	ELSE /* print out current traps */
126	INT i;
127
128	FOR i=0; i<MAXTRAP; i++
129	DO IF trapcom[i]
130	THEN prn(i); prs(colon); prs(trapcom[i]); newline();
131	FI
132	OD
133	FI
134	break;
135
136	case SYSEXEC:
137	com++;
138	initio(io); ioset=0; io=0;
139	IF a1==0 THEN break FI
140
141	case SYSLOGIN:
142	flags \|= forked;
143	oldsigs(); execa(com); done();
144
145	case SYSCD:
146	IF flags&rshflg
147	THEN failed(com[0],restricted);
148	ELIF (a1==0 ANDF (a1=homenod.namval)==0) ORF chdir(a1)<0
149	THEN failed(a1,baddir);
150	FI
151	break;
152
153	case SYSSHFT:
154	IF dolc<1
155	THEN error(badshift);
156	ELSE dolv++; dolc--;
157	FI
158	assnum(&dolladr, dolc);
159	break;
160
161	case SYSWAIT:
162	await(-1);
163	break;
164
165	case SYSREAD:
166	exitval=readvar(&com[1]);
167	break;
168
169	/*
170	case SYSTST:
171	exitval=testcmd(com);
172	break;
173	*/
174
175	case SYSSET:
176	IF a1
177	THEN INT argc;
178	argc = options(argn,com);
179	IF argc>1
180	THEN setargs(com+argn-argc);
181	FI
3cc4dafe	182	ELIF t->comnod.comset==0
f8e636e7 KM	183	THEN /scan name chain and print/
	184	namscan(printnam);
	185	FI
	186	break;
	187
	188	case SYSRDONLY:
	189	exitval=N_RDONLY;
	190	case SYSXPORT:
	191	IF exitval==0 THEN exitval=N_EXPORT; FI
	192
	193	IF a1
	194	THEN WHILE *++com
	195	DO attrib(lookup(*com), exitval) OD
	196	ELSE namscan(printflg);
	197	FI
	198	exitval=0;
	199	break;
	200
	201	case SYSEVAL:
	202	IF a1
	203	THEN execexp(a1,&com[2]);
	204	FI
	205	break;
	206
	207	case SYSUMASK:
	208	if (a1) {
399372bb	209	int c, i;
f8e636e7 KM	210	i = 0;
	211	while ((c = *a1++) >= '0' &&
	212	c <= '7')
	213	i = (i << 3) + c - '0';
	214	umask(i);
	215	} else {
	216	int i, j;
	217	umask(i = umask(0));
	218	prc('0');
	219	for (j = 6; j >= 0; j -= 3)
	220	prc(((i>>j)&07) + '0');
	221	newline();
	222	}
	223	break;
	224
	225	default:
	226	internal=builtin(argn,com);
	227
	228	ENDSW
	229
	230	IF internal
	231	THEN IF io THEN error(illegal) FI
	232	chktrap();
	233	break;
	234	FI
3cc4dafe	235	ELIF t->treio.treio==0
f8e636e7 KM	236	THEN break;
	237	FI
	238	END
	239
	240	case TFORK:
	241	IF execflg ANDF (treeflgs&(FAMP\|FPOU))==0
	242	THEN parent=0;
	243	ELSE WHILE (parent=fork()) == -1
	244	DO sigchk(); alarm(10); pause() OD
	245	FI
	246
	247	IF parent
	248	THEN /* This is the parent branch of fork; */
	249	/* it may or may not wait for the child. */
	250	IF treeflgs&FPRS ANDF flags&ttyflg
	251	THEN prn(parent); newline();
	252	FI
	253	IF treeflgs&FPCL THEN closepipe(pf1) FI
	254	IF (treeflgs&(FAMP\|FPOU))==0
	255	THEN await(parent);
	256	ELIF (treeflgs&FAMP)==0
	257	THEN post(parent);
	258	ELSE assnum(&pcsadr, parent);
	259	FI
	260
	261	chktrap();
	262	break;
	263
	264
	265	ELSE /* this is the forked branch (child) of execute */
	266	flags \|= forked; iotemp=0;
	267	postclr();
	268	settmp();
	269
	270	/* Turn off INTR and QUIT if `FINT' */
	271	/* Reset ramaining signals to parent */
	272	/* except for those `lost' by trap */
	273	oldsigs();
	274	IF treeflgs&FINT
	275	THEN signal(INTR,1); signal(QUIT,1);
	276	FI
	277
	278	/* pipe in or out */
	279	IF treeflgs&FPIN
	280	THEN rename(pf1[INPIPE],0);
	281	close(pf1[OTPIPE]);
	282	FI
	283	IF treeflgs&FPOU
	284	THEN rename(pf2[OTPIPE],1);
	285	close(pf2[INPIPE]);
	286	FI
	287
	288	/* default std input for & */
	289	IF treeflgs&FINT ANDF ioset==0
	290	THEN rename(chkopen(devnull),0);
	291	FI
	292
	293	/* io redirection */
3cc4dafe	294	initio(t->treio.treio);
f8e636e7	295	IF type!=TCOM
3cc4dafe	296	THEN execute(t->forknod.forktre,1);
f8e636e7	297	ELIF com[0]!=ENDARGS
3cc4dafe	298	THEN setlist(t->comnod.comset,N_EXPORT);
f8e636e7 KM	299	execa(com);
	300	FI
	301	done();
	302	FI
	303
	304	case TPAR:
	305	rename(dup(2),output);
3cc4dafe	306	execute(t->parnod.partre,execflg);
f8e636e7 KM	307	done();
	308
	309	case TFIL:
	310	BEGIN
	311	INT pv[2]; chkpipe(pv);
3cc4dafe KB	312	IF execute(t->lstnod.lstlef, 0, pf1, pv)==0
3cc4dafe KB	313	THEN execute(t->lstnod.lstrit, execflg, pv, pf2);
f8e636e7 KM	314	ELSE closepipe(pv);
	315	FI
	316	END
	317	break;
	318
	319	case TLST:
3cc4dafe KB	320	execute(t->lstnod.lstlef,0);
3cc4dafe KB	321	execute(t->lstnod.lstrit,execflg);
f8e636e7 KM	322	break;
	323
	324	case TAND:
3cc4dafe KB	325	IF execute(t->lstnod.lstlef,0)==0
3cc4dafe KB	326	THEN execute(t->lstnod.lstrit,execflg);
f8e636e7 KM	327	FI
	328	break;
	329
	330	case TORF:
3cc4dafe KB	331	IF execute(t->lstnod.lstlef,0)!=0
3cc4dafe KB	332	THEN execute(t->lstnod.lstrit,execflg);
f8e636e7 KM	333	FI
	334	break;
	335
	336	case TFOR:
	337	BEGIN
3cc4dafe	338	NAMPTR n = lookup(t->fornod.fornam);
f8e636e7 KM	339	STRING *args;
	340	DOLPTR argsav=0;
	341
3cc4dafe	342	IF t->fornod.forlst==0
f8e636e7 KM	343	THEN args=dolv+1;
	344	argsav=useargs();
	345	ELSE ARGPTR schain=gchain;
	346	gchain=0;
3cc4dafe	347	trim((args=scan(getarg(t->fornod.forlst)))[0]);
f8e636e7 KM	348	gchain=schain;
	349	FI
	350	loopcnt++;
	351	WHILE *args!=ENDARGS ANDF execbrk==0
	352	DO assign(n,*args++);
3cc4dafe	353	execute(t->fornod.fortre,0);
f8e636e7 KM	354	IF execbrk<0 THEN execbrk=0 FI
	355	OD
	356	IF breakcnt THEN breakcnt-- FI
	357	execbrk=breakcnt; loopcnt--;
	358	argfor=freeargs(argsav);
	359	END
	360	break;
	361
	362	case TWH:
	363	case TUN:
	364	BEGIN
7d79bd40	365	INT i=0, saveflg;
f8e636e7	366
7d79bd40	367	saveflg = flags&errflg;
f8e636e7	368	loopcnt++;
7d79bd40 KB	369	WHILE execbrk==0
7d79bd40 KB	370	DO flags &= ~errflg;
3cc4dafe	371	i=execute(t->whnod.whtre,0);
7d79bd40 KB	372	flags \|= saveflg;
7d79bd40 KB	373	IF (i==0)!=(type==TWH) THEN break FI
3cc4dafe	374	i=execute(t->whnod.dotre,0);
f8e636e7 KM	375	IF execbrk<0 THEN execbrk=0 FI
	376	OD
	377	IF breakcnt THEN breakcnt-- FI
	378	execbrk=breakcnt; loopcnt--; exitval=i;
	379	END
	380	break;
	381
	382	case TIF:
7d79bd40 KB	383	BEGIN
	384	INT i, saveflg;
	385
	386	saveflg = flags&errflg;
	387	flags &= ~errflg;
3cc4dafe	388	i=execute(t->ifnod.iftre,0);
7d79bd40 KB	389	flags \|= saveflg;
7d79bd40 KB	390	IF i==0
3cc4dafe KB	391	THEN execute(t->ifnod.thtre,execflg);
3cc4dafe KB	392	ELSE execute(t->ifnod.eltre,execflg);
7d79bd40 KB	393	FI
7d79bd40 KB	394	END
f8e636e7 KM	395	break;
	396
	397	case TSW:
	398	BEGIN
3cc4dafe KB	399	REG STRING r = mactrim(t->swnod.swarg);
	400	REG REGPTR eg = t->swnod.swlst;
	401	WHILE eg
	402	DO ARGPTR rex=eg->regptr;
f8e636e7 KM	403	WHILE rex
	404	DO REG STRING s;
	405	IF gmatch(r,s=macro(rex->argval)) ORF (trim(s), eq(r,s))
3cc4dafe KB	406	THEN execute(eg->regcom,0);
3cc4dafe KB	407	eg=0; break;
f8e636e7 KM	408	ELSE rex=rex->argnxt;
	409	FI
	410	OD
3cc4dafe	411	IF eg THEN eg=eg->regnxt FI
f8e636e7 KM	412	OD
	413	END
	414	break;
	415	ENDSW
	416	exitset();
	417	FI
	418
	419	sigchk();
	420	tdystak(sav);
	421	return(exitval);
	422	}
	423
	424
	425	execexp(s,f)
	426	STRING s;
	427	UFD f;
	428	{
	429	FILEBLK fb;
	430	push(&fb);
	431	IF s
	432	THEN estabf(s); fb.feval=f;
	433	ELIF f>=0
	434	THEN initf(f);
	435	FI
	436	execute(cmd(NL, NLFLG\|MTFLG),0);
	437	pop();
	438	}