xref: /netbsd-src/bin/csh/csh.c (revision 5f7096188587a2c7c95fa3c69b78e1ec9c7923d0)
1 /*-
2  * Copyright (c) 1980, 1991 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef lint
35 char copyright[] =
36 "@(#) Copyright (c) 1991 The Regents of the University of California.\n\
37  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #ifndef lint
41 /*static char sccsid[] = "from: @(#)csh.c	5.26 (Berkeley) 6/8/91";*/
42 static char rcsid[] = "$Id: csh.c,v 1.5 1993/11/12 15:58:14 cgd Exp $";
43 #endif /* not lint */
44 
45 #include <sys/types.h>
46 #include <sys/ioctl.h>
47 #include <sys/stat.h>
48 #include <fcntl.h>
49 #include <errno.h>
50 #include <pwd.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include <locale.h>
54 #include <unistd.h>
55 #if __STDC__
56 # include <stdarg.h>
57 #else
58 # include <varargs.h>
59 #endif
60 
61 #include "csh.h"
62 #include "extern.h"
63 #include "pathnames.h"
64 #include "proc.h"
65 
66 extern bool MapsAreInited;
67 extern bool NLSMapsAreInited;
68 
69 /*
70  * C Shell
71  *
72  * Bill Joy, UC Berkeley, California, USA
73  * October 1978, May 1980
74  *
75  * Jim Kulp, IIASA, Laxenburg, Austria
76  * April 1980
77  *
78  * Christos Zoulas, Cornell University
79  * June, 1991
80  */
81 
82 Char   *dumphist[] = {STRhistory, STRmh, 0, 0};
83 Char   *loadhist[] = {STRsource, STRmh, STRhistfile, 0};
84 
85 int     nofile = 0;
86 bool    reenter = 0;
87 bool    nverbose = 0;
88 bool    nexececho = 0;
89 bool    quitit = 0;
90 bool    fast = 0;
91 bool    batch = 0;
92 bool    mflag = 0;
93 bool    prompt = 1;
94 bool    enterhist = 0;
95 bool    tellwhat = 0;
96 
97 extern char **environ;
98 
99 static int	srccat __P((Char *, Char *));
100 static int	srcfile __P((char *, bool, bool));
101 static void	phup __P((int));
102 static void	srcunit __P((int, bool, bool));
103 static void	mailchk __P((void));
104 static Char   **defaultpath __P((void));
105 
106 int
107 main(argc, argv)
108     int     argc;
109     char  **argv;
110 {
111     register Char *cp;
112     register char *tcp;
113     register int f;
114     register char **tempv;
115     struct sigvec osv;
116 
117 
118     settimes();			/* Immed. estab. timing base */
119 
120     /*
121      * Initialize non constant strings
122      */
123 #ifdef _PATH_BSHELL
124     STR_BSHELL = SAVE(_PATH_BSHELL);
125 #endif
126 #ifdef _PATH_CSHELL
127     STR_SHELLPATH = SAVE(_PATH_CSHELL);
128 #endif
129     STR_environ = blk2short(environ);
130     environ = short2blk(STR_environ);	/* So that we can free it */
131     STR_WORD_CHARS = SAVE(WORD_CHARS);
132 
133     HIST = '!';
134     HISTSUB = '^';
135     word_chars = STR_WORD_CHARS;
136 
137     tempv = argv;
138     if (eq(str2short(tempv[0]), STRaout))	/* A.out's are quittable */
139 	quitit = 1;
140     uid = getuid();
141     gid = getgid();
142     /*
143      * We are a login shell if: 1. we were invoked as -<something> and we had
144      * no arguments 2. or we were invoked only with the -l flag
145      */
146     loginsh = (**tempv == '-' && argc == 1) ||
147 	(argc == 2 && tempv[1][0] == '-' && tempv[1][1] == 'l' &&
148 	 tempv[1][2] == '\0');
149 
150     if (loginsh && **tempv != '-') {
151 	/*
152 	 * Mangle the argv space
153 	 */
154 	tempv[1][0] = '\0';
155 	tempv[1][1] = '\0';
156 	tempv[1] = NULL;
157 	for (tcp = *tempv; *tcp++;);
158 	for (tcp--; tcp >= *tempv; tcp--)
159 	    tcp[1] = tcp[0];
160 	*++tcp = '-';
161 	argc--;
162     }
163     if (loginsh)
164 	(void) time(&chktim);
165 
166     AsciiOnly = 1;
167 #ifdef NLS
168     (void) setlocale(LC_ALL, "");
169     {
170 	int     k;
171 
172 	for (k = 0200; k <= 0377 && !Isprint(k); k++);
173 	AsciiOnly = k > 0377;
174     }
175 #else
176     AsciiOnly = getenv("LANG") == NULL && getenv("LC_CTYPE") == NULL;
177 #endif				/* NLS */
178 
179     /*
180      * Move the descriptors to safe places. The variable didfds is 0 while we
181      * have only FSH* to work with. When didfds is true, we have 0,1,2 and
182      * prefer to use these.
183      */
184     initdesc();
185 
186     /*
187      * Initialize the shell variables. ARGV and PROMPT are initialized later.
188      * STATUS is also munged in several places. CHILD is munged when
189      * forking/waiting
190      */
191     set(STRstatus, Strsave(STR0));
192 
193     if ((tcp = getenv("HOME")) != NULL)
194 	cp = SAVE(tcp);
195     else
196 	cp = NULL;
197 
198     if (cp == NULL)
199 	fast = 1;		/* No home -> can't read scripts */
200     else
201 	set(STRhome, cp);
202     dinit(cp);			/* dinit thinks that HOME == cwd in a login
203 				 * shell */
204     /*
205      * Grab other useful things from the environment. Should we grab
206      * everything??
207      */
208     if ((tcp = getenv("LOGNAME")) != NULL ||
209 	(tcp = getenv("USER")) != NULL)
210 	set(STRuser, SAVE(tcp));
211     if ((tcp = getenv("TERM")) != NULL)
212 	set(STRterm, SAVE(tcp));
213 
214     /*
215      * Re-initialize path if set in environment
216      */
217     if ((tcp = getenv("PATH")) == NULL)
218 	set1(STRpath, defaultpath(), &shvhed);
219     else
220 	importpath(SAVE(tcp));
221 
222     set(STRshell, Strsave(STR_SHELLPATH));
223 
224     doldol = putn((int) getpid());	/* For $$ */
225     shtemp = Strspl(STRtmpsh, doldol);	/* For << */
226 
227     /*
228      * Record the interrupt states from the parent process. If the parent is
229      * non-interruptible our hand must be forced or we (and our children) won't
230      * be either. Our children inherit termination from our parent. We catch it
231      * only if we are the login shell.
232      */
233     /* parents interruptibility */
234     (void) sigvec(SIGINT, NULL, &osv);
235     parintr = (void (*) ()) osv.sv_handler;
236     (void) sigvec(SIGTERM, NULL, &osv);
237     parterm = (void (*) ()) osv.sv_handler;
238 
239     /* catch these all, login shell or not */
240     (void) signal(SIGHUP, phup);	/* exit processing on HUP */
241     (void) signal(SIGXCPU, phup);	/* ...and on XCPU */
242     (void) signal(SIGXFSZ, phup);	/* ...and on XFSZ */
243 
244     /*
245      * Process the arguments.
246      *
247      * Note that processing of -v/-x is actually delayed till after script
248      * processing.
249      *
250      * We set the first character of our name to be '-' if we are a shell running
251      * interruptible commands.  Many programs which examine ps'es use this to
252      * filter such shells out.
253      */
254     argc--, tempv++;
255     while (argc > 0 && (tcp = tempv[0])[0] == '-' && *++tcp != '\0' && !batch) {
256 	do
257 	    switch (*tcp++) {
258 
259 	    case 0:		/* -	Interruptible, no prompt */
260 		prompt = 0;
261 		setintr = 1;
262 		nofile = 1;
263 		break;
264 
265 	    case 'b':		/* -b	Next arg is input file */
266 		batch = 1;
267 		break;
268 
269 	    case 'c':		/* -c	Command input from arg */
270 		if (argc == 1)
271 		    xexit(0);
272 		argc--, tempv++;
273 		arginp = SAVE(tempv[0]);
274 		prompt = 0;
275 		nofile = 1;
276 		break;
277 
278 	    case 'e':		/* -e	Exit on any error */
279 		exiterr = 1;
280 		break;
281 
282 	    case 'f':		/* -f	Fast start */
283 		fast = 1;
284 		break;
285 
286 	    case 'i':		/* -i	Interactive, even if !intty */
287 		intact = 1;
288 		nofile = 1;
289 		break;
290 
291 	    case 'm':		/* -m	read .cshrc (from su) */
292 		mflag = 1;
293 		break;
294 
295 	    case 'n':		/* -n	Don't execute */
296 		noexec = 1;
297 		break;
298 
299 	    case 'q':		/* -q	(Undoc'd) ... die on quit */
300 		quitit = 1;
301 		break;
302 
303 	    case 's':		/* -s	Read from std input */
304 		nofile = 1;
305 		break;
306 
307 	    case 't':		/* -t	Read one line from input */
308 		onelflg = 2;
309 		prompt = 0;
310 		nofile = 1;
311 		break;
312 
313 	    case 'v':		/* -v	Echo hist expanded input */
314 		nverbose = 1;	/* ... later */
315 		break;
316 
317 	    case 'x':		/* -x	Echo just before execution */
318 		nexececho = 1;	/* ... later */
319 		break;
320 
321 	    case 'V':		/* -V	Echo hist expanded input */
322 		setNS(STRverbose);	/* NOW! */
323 		break;
324 
325 	    case 'X':		/* -X	Echo just before execution */
326 		setNS(STRecho);	/* NOW! */
327 		break;
328 
329 	} while (*tcp);
330 	tempv++, argc--;
331     }
332 
333     if (quitit)			/* With all due haste, for debugging */
334 	(void) signal(SIGQUIT, SIG_DFL);
335 
336     /*
337      * Unless prevented by -, -c, -i, -s, or -t, if there are remaining
338      * arguments the first of them is the name of a shell file from which to
339      * read commands.
340      */
341     if (nofile == 0 && argc > 0) {
342 	nofile = open(tempv[0], O_RDONLY);
343 	if (nofile < 0) {
344 	    child = 1;		/* So this doesn't return */
345 	    stderror(ERR_SYSTEM, tempv[0], strerror(errno));
346 	}
347 	ffile = SAVE(tempv[0]);
348 	/*
349 	 * Replace FSHIN. Handle /dev/std{in,out,err} specially
350 	 * since once they are closed we cannot open them again.
351 	 * In that case we use our own saved descriptors
352 	 */
353 	if ((SHIN = dmove(nofile, FSHIN)) < 0)
354 	    switch(nofile) {
355 	    case 0:
356 		SHIN = FSHIN;
357 		break;
358 	    case 1:
359 		SHIN = FSHOUT;
360 		break;
361 	    case 2:
362 		SHIN = FSHDIAG;
363 		break;
364 	    default:
365 		stderror(ERR_SYSTEM, tempv[0], strerror(errno));
366 		break;
367 	    }
368 	(void) ioctl(SHIN, FIOCLEX, NULL);
369 	prompt = 0;
370 	 /* argc not used any more */ tempv++;
371     }
372     intty = isatty(SHIN);
373     intty |= intact;
374     if (intty || (intact && isatty(SHOUT))) {
375 	if (!batch && (uid != geteuid() || gid != getegid())) {
376 	    errno = EACCES;
377 	    child = 1;		/* So this doesn't return */
378 	    stderror(ERR_SYSTEM, "csh", strerror(errno));
379 	}
380     }
381     /*
382      * Decide whether we should play with signals or not. If we are explicitly
383      * told (via -i, or -) or we are a login shell (arg0 starts with -) or the
384      * input and output are both the ttys("csh", or "csh</dev/ttyx>/dev/ttyx")
385      * Note that in only the login shell is it likely that parent may have set
386      * signals to be ignored
387      */
388     if (loginsh || intact || intty && isatty(SHOUT))
389 	setintr = 1;
390     settell();
391     /*
392      * Save the remaining arguments in argv.
393      */
394     setq(STRargv, blk2short(tempv), &shvhed);
395 
396     /*
397      * Set up the prompt.
398      */
399     if (prompt) {
400 	set(STRprompt, Strsave(uid == 0 ? STRsymhash : STRsymcent));
401 	/* that's a meta-questionmark */
402 	set(STRprompt2, Strsave(STRmquestion));
403     }
404 
405     /*
406      * If we are an interactive shell, then start fiddling with the signals;
407      * this is a tricky game.
408      */
409     shpgrp = getpgrp();
410     opgrp = tpgrp = -1;
411     if (setintr) {
412 	**argv = '-';
413 	if (!quitit)		/* Wary! */
414 	    (void) signal(SIGQUIT, SIG_IGN);
415 	(void) signal(SIGINT, pintr);
416 	(void) sigblock(sigmask(SIGINT));
417 	(void) signal(SIGTERM, SIG_IGN);
418 	if (quitit == 0 && arginp == 0) {
419 	    (void) signal(SIGTSTP, SIG_IGN);
420 	    (void) signal(SIGTTIN, SIG_IGN);
421 	    (void) signal(SIGTTOU, SIG_IGN);
422 	    /*
423 	     * Wait till in foreground, in case someone stupidly runs csh &
424 	     * dont want to try to grab away the tty.
425 	     */
426 	    if (isatty(FSHDIAG))
427 		f = FSHDIAG;
428 	    else if (isatty(FSHOUT))
429 		f = FSHOUT;
430 	    else if (isatty(OLDSTD))
431 		f = OLDSTD;
432 	    else
433 		f = -1;
434     retry:
435 	    if ((tpgrp = tcgetpgrp(f)) != -1) {
436 		if (tpgrp != shpgrp) {
437 		    sig_t old = signal(SIGTTIN, SIG_DFL);
438 		    (void) kill(0, SIGTTIN);
439 		    (void) signal(SIGTTIN, old);
440 		    goto retry;
441 		}
442 		opgrp = shpgrp;
443 		shpgrp = getpid();
444 		tpgrp = shpgrp;
445 		/*
446 		 * Setpgid will fail if we are a session leader and
447 		 * mypid == mypgrp (POSIX 4.3.3)
448 		 */
449 		if (opgrp != shpgrp)
450 		    if (setpgid(0, shpgrp) == -1)
451 			goto notty;
452 		/*
453 		 * We do that after we set our process group, to make sure
454 		 * that the process group belongs to a process in the same
455 		 * session as the tty (our process and our group) (POSIX 7.2.4)
456 		 */
457 		if (tcsetpgrp(f, shpgrp) == -1)
458 		    goto notty;
459 		(void) ioctl(dcopy(f, FSHTTY), FIOCLEX, NULL);
460 	    }
461 	    if (tpgrp == -1) {
462 notty:
463 		xprintf("Warning: no access to tty (%s).\n", strerror(errno));
464 		xprintf("Thus no job control in this shell.\n");
465 	    }
466 	}
467     }
468     if ((setintr == 0) && (parintr == SIG_DFL))
469 	setintr = 1;
470     (void) signal(SIGCHLD, pchild);	/* while signals not ready */
471 
472     /*
473      * Set an exit here in case of an interrupt or error reading the shell
474      * start-up scripts.
475      */
476     reenter = setexit();	/* PWP */
477     haderr = 0;			/* In case second time through */
478     if (!fast && reenter == 0) {
479 	/* Will have value(STRhome) here because set fast if don't */
480 	{
481 	    int     osetintr = setintr;
482 	    sigset_t omask = sigblock(sigmask(SIGINT));
483 
484 	    setintr = 0;
485 #ifdef _PATH_DOTCSHRC
486 	    (void) srcfile(_PATH_DOTCSHRC, 0, 0);
487 #endif
488 	    if (!fast && !arginp && !onelflg)
489 		dohash();
490 #ifdef _PATH_DOTLOGIN
491 	    if (loginsh)
492 		(void) srcfile(_PATH_DOTLOGIN, 0, 0);
493 #endif
494 	    (void) sigsetmask(omask);
495 	    setintr = osetintr;
496 	}
497 	(void) srccat(value(STRhome), STRsldotcshrc);
498 
499 	if (!fast && !arginp && !onelflg && !havhash)
500 	    dohash();
501         if (loginsh)
502 	      (void) srccat(value(STRhome), STRsldotlogin);
503 	dosource(loadhist);
504     }
505 
506     /*
507      * Now are ready for the -v and -x flags
508      */
509     if (nverbose)
510 	setNS(STRverbose);
511     if (nexececho)
512 	setNS(STRecho);
513 
514     /*
515      * All the rest of the world is inside this call. The argument to process
516      * indicates whether it should catch "error unwinds".  Thus if we are a
517      * interactive shell our call here will never return by being blown past on
518      * an error.
519      */
520     process(setintr);
521 
522     /*
523      * Mop-up.
524      */
525     if (intty) {
526 	if (loginsh) {
527 	    xprintf("logout\n");
528 	    (void) close(SHIN);
529 	    child = 1;
530 	    goodbye();
531 	}
532 	else {
533 	    xprintf("exit\n");
534 	}
535     }
536     rechist();
537     exitstat();
538     return (0);
539 }
540 
541 void
542 untty()
543 {
544     if (tpgrp > 0) {
545 	(void) setpgid(0, opgrp);
546 	(void) tcsetpgrp(FSHTTY, opgrp);
547     }
548 }
549 
550 void
551 importpath(cp)
552     Char   *cp;
553 {
554     register int i = 0;
555     register Char *dp;
556     register Char **pv;
557     int     c;
558 
559     for (dp = cp; *dp; dp++)
560 	if (*dp == ':')
561 	    i++;
562     /*
563      * i+2 where i is the number of colons in the path. There are i+1
564      * directories in the path plus we need room for a zero terminator.
565      */
566     pv = (Char **) xcalloc((size_t) (i + 2), sizeof(Char **));
567     dp = cp;
568     i = 0;
569     if (*dp)
570 	for (;;) {
571 	    if ((c = *dp) == ':' || c == 0) {
572 		*dp = 0;
573 		pv[i++] = Strsave(*cp ? cp : STRdot);
574 		if (c) {
575 		    cp = dp + 1;
576 		    *dp = ':';
577 		}
578 		else
579 		    break;
580 	    }
581 	    dp++;
582 	}
583     pv[i] = 0;
584     set1(STRpath, pv, &shvhed);
585 }
586 
587 /*
588  * Source to the file which is the catenation of the argument names.
589  */
590 static int
591 srccat(cp, dp)
592     Char   *cp, *dp;
593 {
594     register Char *ep = Strspl(cp, dp);
595     char   *ptr = short2str(ep);
596 
597     xfree((ptr_t) ep);
598     return srcfile(ptr, mflag ? 0 : 1, 0);
599 }
600 
601 /*
602  * Source to a file putting the file descriptor in a safe place (> 2).
603  */
604 static int
605 srcfile(f, onlyown, flag)
606     char   *f;
607     bool    onlyown, flag;
608 {
609     register int unit;
610 
611     if ((unit = open(f, O_RDONLY)) == -1)
612 	return 0;
613     unit = dmove(unit, -1);
614 
615     (void) ioctl(unit, FIOCLEX, NULL);
616     srcunit(unit, onlyown, flag);
617     return 1;
618 }
619 
620 /*
621  * Source to a unit.  If onlyown it must be our file or our group or
622  * we don't chance it.	This occurs on ".cshrc"s and the like.
623  */
624 int     insource;
625 static void
626 srcunit(unit, onlyown, hflg)
627     register int unit;
628     bool    onlyown, hflg;
629 {
630     /* We have to push down a lot of state here */
631     /* All this could go into a structure */
632     int     oSHIN = -1, oldintty = intty, oinsource = insource;
633     struct whyle *oldwhyl = whyles;
634     Char   *ogointr = gointr, *oarginp = arginp;
635     Char   *oevalp = evalp, **oevalvec = evalvec;
636     int     oonelflg = onelflg;
637     bool    oenterhist = enterhist;
638     char    OHIST = HIST;
639     bool    otell = cantell;
640 
641     struct Bin saveB;
642     sigset_t omask;
643     jmp_buf oldexit;
644 
645     /* The (few) real local variables */
646     int     my_reenter;
647 
648     if (unit < 0)
649 	return;
650     if (didfds)
651 	donefds();
652     if (onlyown) {
653 	struct stat stb;
654 
655 	if (fstat(unit, &stb) < 0) {
656 	    (void) close(unit);
657 	    return;
658 	}
659     }
660 
661     /*
662      * There is a critical section here while we are pushing down the input
663      * stream since we have stuff in different structures. If we weren't
664      * careful an interrupt could corrupt SHIN's Bin structure and kill the
665      * shell.
666      *
667      * We could avoid the critical region by grouping all the stuff in a single
668      * structure and pointing at it to move it all at once.  This is less
669      * efficient globally on many variable references however.
670      */
671     insource = 1;
672     getexit(oldexit);
673     omask = 0;
674 
675     if (setintr)
676 	omask = sigblock(sigmask(SIGINT));
677     /* Setup the new values of the state stuff saved above */
678     bcopy((char *) &B, (char *) &(saveB), sizeof(B));
679     fbuf = NULL;
680     fseekp = feobp = fblocks = 0;
681     oSHIN = SHIN, SHIN = unit, arginp = 0, onelflg = 0;
682     intty = isatty(SHIN), whyles = 0, gointr = 0;
683     evalvec = 0;
684     evalp = 0;
685     enterhist = hflg;
686     if (enterhist)
687 	HIST = '\0';
688 
689     /*
690      * Now if we are allowing commands to be interrupted, we let ourselves be
691      * interrupted.
692      */
693     if (setintr)
694 	(void) sigsetmask(omask);
695     settell();
696 
697     if ((my_reenter = setexit()) == 0)
698 	process(0);		/* 0 -> blow away on errors */
699 
700     if (setintr)
701 	(void) sigsetmask(omask);
702     if (oSHIN >= 0) {
703 	register int i;
704 
705 	/* We made it to the new state... free up its storage */
706 	/* This code could get run twice but xfree doesn't care */
707 	for (i = 0; i < fblocks; i++)
708 	    xfree((ptr_t) fbuf[i]);
709 	xfree((ptr_t) fbuf);
710 
711 	/* Reset input arena */
712 	bcopy((char *) &(saveB), (char *) &B, sizeof(B));
713 
714 	(void) close(SHIN), SHIN = oSHIN;
715 	arginp = oarginp, onelflg = oonelflg;
716 	evalp = oevalp, evalvec = oevalvec;
717 	intty = oldintty, whyles = oldwhyl, gointr = ogointr;
718 	if (enterhist)
719 	    HIST = OHIST;
720 	enterhist = oenterhist;
721 	cantell = otell;
722     }
723 
724     resexit(oldexit);
725     /*
726      * If process reset() (effectively an unwind) then we must also unwind.
727      */
728     if (my_reenter)
729 	stderror(ERR_SILENT);
730     insource = oinsource;
731 }
732 
733 void
734 rechist()
735 {
736     Char    buf[BUFSIZ];
737     int     fp, ftmp, oldidfds;
738 
739     if (!fast) {
740 	if (value(STRsavehist)[0] == '\0')
741 	    return;
742 	(void) Strcpy(buf, value(STRhome));
743 	(void) Strcat(buf, STRsldthist);
744 	fp = creat(short2str(buf), 0600);
745 	if (fp == -1)
746 	    return;
747 	oldidfds = didfds;
748 	didfds = 0;
749 	ftmp = SHOUT;
750 	SHOUT = fp;
751 	(void) Strcpy(buf, value(STRsavehist));
752 	dumphist[2] = buf;
753 	dohist(dumphist);
754 	(void) close(fp);
755 	SHOUT = ftmp;
756 	didfds = oldidfds;
757     }
758 }
759 
760 void
761 goodbye()
762 {
763     rechist();
764 
765     if (loginsh) {
766 	(void) signal(SIGQUIT, SIG_IGN);
767 	(void) signal(SIGINT, SIG_IGN);
768 	(void) signal(SIGTERM, SIG_IGN);
769 	setintr = 0;		/* No interrupts after "logout" */
770 	if (!(adrof(STRlogout)))
771 	    set(STRlogout, STRnormal);
772 #ifdef _PATH_DOTLOGOUT
773 	(void) srcfile(_PATH_DOTLOGOUT, 0, 0);
774 #endif
775 	if (adrof(STRhome))
776 	    (void) srccat(value(STRhome), STRsldtlogout);
777     }
778     exitstat();
779 }
780 
781 void
782 exitstat()
783 {
784 
785 #ifdef PROF
786     monitor(0);
787 #endif
788     /*
789      * Note that if STATUS is corrupted (i.e. getn bombs) then error will exit
790      * directly because we poke child here. Otherwise we might continue
791      * unwarrantedly (sic).
792      */
793     child = 1;
794     xexit(getn(value(STRstatus)));
795 }
796 
797 /*
798  * in the event of a HUP we want to save the history
799  */
800 static void
801 phup(sig)
802 int sig;
803 {
804 	struct process *pp, *np;
805 	int foregnd;
806 
807 	rechist();
808 
809 	/*
810 	 * the following adopted from tcsh with light mods
811 	 *
812 	 * We kill the last foreground process group. It then becomes
813 	 * responsible to propagate the SIGHUP to its progeny.
814 	 */
815 	for (pp = proclist.p_next; pp; pp = pp->p_next) {
816 		np = pp;
817 		foregnd = 0;
818 
819 		/*
820 		 * Find if this job is in the foreground. It could be that
821 		 * the process leader has exited and the foreground flag
822 		 * is cleared for it.
823 		 */
824 		do {
825 			/*
826 			 * If a process is in the foreground; we try to kill
827 			 * it's process group. If we succeed, then the
828 			 * whole job is gone. Otherwise we keep going...
829 			 * But avoid sending HUP to the shell again.
830 			 */
831 			if ((np->p_flags & PFOREGND) != 0 &&
832 			    np->p_jobid != shpgrp &&
833 			    killpg(np->p_jobid, SIGHUP) != -1) {
834 				/* In case the job was suspended... */
835 				(void) killpg(np->p_jobid, SIGCONT);
836 				break;
837 			}
838 		} while ((np = np->p_friends) != pp);
839         }
840 
841 	xexit(sig);
842 }
843 
844 Char   *jobargv[2] = {STRjobs, 0};
845 
846 /*
847  * Catch an interrupt, e.g. during lexical input.
848  * If we are an interactive shell, we reset the interrupt catch
849  * immediately.  In any case we drain the shell output,
850  * and finally go through the normal error mechanism, which
851  * gets a chance to make the shell go away.
852  */
853 /* ARGSUSED */
854 void
855 pintr(notused)
856 	int notused;
857 {
858     pintr1(1);
859 }
860 
861 void
862 pintr1(wantnl)
863     bool    wantnl;
864 {
865     register Char **v;
866     sigset_t omask;
867 
868     omask = sigblock((sigset_t) 0);
869     if (setintr) {
870 	(void) sigsetmask(omask & ~sigmask(SIGINT));
871 	if (pjobs) {
872 	    pjobs = 0;
873 	    xprintf("\n");
874 	    dojobs(jobargv);
875 	    stderror(ERR_NAME | ERR_INTR);
876 	}
877     }
878     (void) sigsetmask(omask & ~sigmask(SIGCHLD));
879     draino();
880     (void) endpwent();
881 
882     /*
883      * If we have an active "onintr" then we search for the label. Note that if
884      * one does "onintr -" then we shan't be interruptible so we needn't worry
885      * about that here.
886      */
887     if (gointr) {
888 	search(T_GOTO, 0, gointr);
889 	timflg = 0;
890 	if (v = pargv)
891 	    pargv = 0, blkfree(v);
892 	if (v = gargv)
893 	    gargv = 0, blkfree(v);
894 	reset();
895     }
896     else if (intty && wantnl) {
897 	(void) putraw('\r');
898 	(void) putraw('\n');
899     }
900     stderror(ERR_SILENT);
901 }
902 
903 /*
904  * Process is the main driving routine for the shell.
905  * It runs all command processing, except for those within { ... }
906  * in expressions (which is run by a routine evalav in sh.exp.c which
907  * is a stripped down process), and `...` evaluation which is run
908  * also by a subset of this code in sh.glob.c in the routine backeval.
909  *
910  * The code here is a little strange because part of it is interruptible
911  * and hence freeing of structures appears to occur when none is necessary
912  * if this is ignored.
913  *
914  * Note that if catch is not set then we will unwind on any error.
915  * If an end-of-file occurs, we return.
916  */
917 void
918 process(catch)
919     bool    catch;
920 {
921     jmp_buf osetexit;
922     struct command *t;
923 
924     getexit(osetexit);
925     for (;;) {
926 	pendjob();
927 	paraml.next = paraml.prev = &paraml;
928 	paraml.word = STRNULL;
929 	t = 0;
930 	(void) setexit();
931 	justpr = enterhist;	/* execute if not entering history */
932 
933 	/*
934 	 * Interruptible during interactive reads
935 	 */
936 	if (setintr)
937 	    (void) sigsetmask(sigblock((sigset_t) 0) & ~sigmask(SIGINT));
938 
939 	/*
940 	 * For the sake of reset()
941 	 */
942 	freelex(&paraml);
943 	freesyn(t);
944 	t = 0;
945 
946 	if (haderr) {
947 	    if (!catch) {
948 		/* unwind */
949 		doneinp = 0;
950 		resexit(osetexit);
951 		reset();
952 	    }
953 	    haderr = 0;
954 	    /*
955 	     * Every error is eventually caught here or the shell dies.  It is
956 	     * at this point that we clean up any left-over open files, by
957 	     * closing all but a fixed number of pre-defined files.  Thus
958 	     * routines don't have to worry about leaving files open due to
959 	     * deeper errors... they will get closed here.
960 	     */
961 	    closem();
962 	    continue;
963 	}
964 	if (doneinp) {
965 	    doneinp = 0;
966 	    break;
967 	}
968 	if (chkstop)
969 	    chkstop--;
970 	if (neednote)
971 	    pnote();
972 	if (intty && prompt && evalvec == 0) {
973 	    mailchk();
974 	    /*
975 	     * If we are at the end of the input buffer then we are going to
976 	     * read fresh stuff. Otherwise, we are rereading input and don't
977 	     * need or want to prompt.
978 	     */
979 	    if (fseekp == feobp)
980 		printprompt();
981 	    flush();
982 	}
983 	if (seterr) {
984 	    xfree((ptr_t) seterr);
985 	    seterr = NULL;
986 	}
987 
988 	/*
989 	 * Echo not only on VERBOSE, but also with history expansion. If there
990 	 * is a lexical error then we forego history echo.
991 	 */
992 	if (lex(&paraml) && !seterr && intty || adrof(STRverbose)) {
993 	    haderr = 1;
994 	    prlex(&paraml);
995 	    haderr = 0;
996 	}
997 
998 	/*
999 	 * The parser may lose space if interrupted.
1000 	 */
1001 	if (setintr)
1002 	    (void) sigblock(sigmask(SIGINT));
1003 
1004 	/*
1005 	 * Save input text on the history list if reading in old history, or it
1006 	 * is from the terminal at the top level and not in a loop.
1007 	 *
1008 	 * PWP: entry of items in the history list while in a while loop is done
1009 	 * elsewhere...
1010 	 */
1011 	if (enterhist || catch && intty && !whyles)
1012 	    savehist(&paraml);
1013 
1014 	/*
1015 	 * Print lexical error messages, except when sourcing history lists.
1016 	 */
1017 	if (!enterhist && seterr)
1018 	    stderror(ERR_OLD);
1019 
1020 	/*
1021 	 * If had a history command :p modifier then this is as far as we
1022 	 * should go
1023 	 */
1024 	if (justpr)
1025 	    reset();
1026 
1027 	alias(&paraml);
1028 
1029 	/*
1030 	 * Parse the words of the input into a parse tree.
1031 	 */
1032 	t = syntax(paraml.next, &paraml, 0);
1033 	if (seterr)
1034 	    stderror(ERR_OLD);
1035 
1036 	execute(t, (tpgrp > 0 ? tpgrp : -1), NULL, NULL);
1037 
1038 	/*
1039 	 * Made it!
1040 	 */
1041 	freelex(&paraml);
1042 	freesyn(t);
1043     }
1044     resexit(osetexit);
1045 }
1046 
1047 void
1048 dosource(t)
1049     register Char **t;
1050 {
1051     register Char *f;
1052     bool    hflg = 0;
1053     Char    buf[BUFSIZ];
1054 
1055     t++;
1056     if (*t && eq(*t, STRmh)) {
1057 	if (*++t == NULL)
1058 	    stderror(ERR_NAME | ERR_HFLAG);
1059 	hflg++;
1060     }
1061     (void) Strcpy(buf, *t);
1062     f = globone(buf, G_ERROR);
1063     (void) strcpy((char *) buf, short2str(f));
1064     xfree((ptr_t) f);
1065     if (!srcfile((char *) buf, 0, hflg) && !hflg)
1066 	stderror(ERR_SYSTEM, (char *) buf, strerror(errno));
1067 }
1068 
1069 /*
1070  * Check for mail.
1071  * If we are a login shell, then we don't want to tell
1072  * about any mail file unless its been modified
1073  * after the time we started.
1074  * This prevents us from telling the user things he already
1075  * knows, since the login program insists on saying
1076  * "You have mail."
1077  */
1078 static void
1079 mailchk()
1080 {
1081     register struct varent *v;
1082     register Char **vp;
1083     time_t  t;
1084     int     intvl, cnt;
1085     struct stat stb;
1086     bool    new;
1087 
1088     v = adrof(STRmail);
1089     if (v == 0)
1090 	return;
1091     (void) time(&t);
1092     vp = v->vec;
1093     cnt = blklen(vp);
1094     intvl = (cnt && number(*vp)) ? (--cnt, getn(*vp++)) : MAILINTVL;
1095     if (intvl < 1)
1096 	intvl = 1;
1097     if (chktim + intvl > t)
1098 	return;
1099     for (; *vp; vp++) {
1100 	if (stat(short2str(*vp), &stb) < 0)
1101 	    continue;
1102 	new = stb.st_mtime > time0.tv_sec;
1103 	if (stb.st_size == 0 || stb.st_atime > stb.st_mtime ||
1104 	    (stb.st_atime < chktim && stb.st_mtime < chktim) ||
1105 	    loginsh && !new)
1106 	    continue;
1107 	if (cnt == 1)
1108 	    xprintf("You have %smail.\n", new ? "new " : "");
1109 	else
1110 	    xprintf("%s in %s.\n", new ? "New mail" : "Mail", short2str(*vp));
1111     }
1112     chktim = t;
1113 }
1114 
1115 /*
1116  * Extract a home directory from the password file
1117  * The argument points to a buffer where the name of the
1118  * user whose home directory is sought is currently.
1119  * We write the home directory of the user back there.
1120  */
1121 int
1122 gethdir(home)
1123     Char   *home;
1124 {
1125     Char   *h;
1126     struct passwd *pw;
1127 
1128     /*
1129      * Is it us?
1130      */
1131     if (*home == '\0') {
1132 	if (h = value(STRhome)) {
1133 	    (void) Strcpy(home, h);
1134 	    return 0;
1135 	}
1136 	else
1137 	    return 1;
1138     }
1139 
1140     if (pw = getpwnam(short2str(home))) {
1141 	(void) Strcpy(home, str2short(pw->pw_dir));
1142 	return 0;
1143     }
1144     else
1145 	return 1;
1146 }
1147 
1148 /*
1149  * Move the initial descriptors to their eventual
1150  * resting places, closin all other units.
1151  */
1152 void
1153 initdesc()
1154 {
1155 
1156     didfds = 0;			/* 0, 1, 2 aren't set up */
1157     (void) ioctl(SHIN = dcopy(0, FSHIN), FIOCLEX, NULL);
1158     (void) ioctl(SHOUT = dcopy(1, FSHOUT), FIOCLEX, NULL);
1159     (void) ioctl(SHDIAG = dcopy(2, FSHDIAG), FIOCLEX, NULL);
1160     (void) ioctl(OLDSTD = dcopy(SHIN, FOLDSTD), FIOCLEX, NULL);
1161     closem();
1162 }
1163 
1164 
1165 void
1166 #ifdef PROF
1167 done(i)
1168 #else
1169 xexit(i)
1170 #endif
1171     int     i;
1172 {
1173     untty();
1174     _exit(i);
1175 }
1176 
1177 static Char **
1178 defaultpath()
1179 {
1180     char   *ptr;
1181     Char  **blk, **blkp;
1182     struct stat stb;
1183 
1184     blkp = blk = (Char **) xmalloc((size_t) sizeof(Char *) * 10);
1185 
1186 #define DIRAPPEND(a)  \
1187 	if (stat(ptr = a, &stb) == 0 && (stb.st_mode & S_IFMT) == S_IFDIR) \
1188 		*blkp++ = SAVE(ptr)
1189 
1190     DIRAPPEND(_PATH_BIN);
1191     DIRAPPEND(_PATH_USRBIN);
1192 
1193 #undef DIRAPPEND
1194 
1195     *blkp++ = Strsave(STRdot);
1196     *blkp = NULL;
1197     return (blk);
1198 }
1199 
1200 void
1201 printprompt()
1202 {
1203     register Char *cp;
1204 
1205     if (!whyles) {
1206 	for (cp = value(STRprompt); *cp; cp++)
1207 	    if (*cp == HIST)
1208 		xprintf("%d", eventno + 1);
1209 	    else {
1210 		if (*cp == '\\' && cp[1] == HIST)
1211 		    cp++;
1212 		xputchar(*cp | QUOTE);
1213 	    }
1214     }
1215     else
1216 	/*
1217 	 * Prompt for forward reading loop body content.
1218 	 */
1219 	xprintf("? ");
1220     flush();
1221 }
1222