xref: /illumos-gate/usr/src/cmd/csh/sh.c (revision 09fbbb7d1b5a956a9b81304070dcff318a4a158e)
1 /*
2  * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
3  * Copyright (c) 2016 by Delphix. All rights reserved.
4  */
5 
6 /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
7 /*	  All Rights Reserved	*/
8 
9 /*
10  * Copyright (c) 1980 Regents of the University of California.
11  * All rights reserved.  The Berkeley Software License Agreement
12  * specifies the terms and conditions for redistribution.
13  */
14 
15 #include <locale.h>
16 #include "sh.h"
17 /* #include <sys/ioctl.h> */
18 #include <fcntl.h>
19 #include <sys/filio.h>
20 #include "sh.tconst.h"
21 #include <pwd.h>
22 #include <stdlib.h>
23 #ifdef	TRACE
24 #include <stdio.h>
25 #endif
26 
27 /*
28  * We use these csh(1) private versions of the select macros, (see select(3C))
29  * so as not to be limited by the size of struct fd_set (ie 1024).
30  */
31 #define	CSH_FD_SET(n, p)   ((*((p) + ((n)/NFDBITS))) |= (1 << ((n) % NFDBITS)))
32 #define	CSH_FD_CLR(n, p)   ((*((p) + ((n)/NFDBITS))) &= ~(1 << ((n) % NFDBITS)))
33 #define	CSH_FD_ISSET(n, p) ((*((p) + ((n)/NFDBITS))) & (1 << ((n) % NFDBITS)))
34 #define	CSH_FD_ZERO(p, n)  memset((void *)(p), 0,  (n))
35 
36 tchar *pathlist[] =	{ S_usrbin /* "/usr/bin" */, S_DOT /* "." */, 0 };
37 tchar *dumphist[] =	{ S_history /* "history" */, S_h /* "-h" */, 0, 0 };
38 tchar *loadhist[] =	{ S_source /* "source" */, S_h /* "-h" */,
39     S_NDOThistory /* "~/.history" */, 0 };
40 tchar HIST = '!';
41 tchar HISTSUB = '^';
42 int	nofile;
43 bool	reenter;
44 bool	nverbose;
45 bool	nexececho;
46 bool	quitit;
47 bool	fast;
48 bool	batch;
49 bool	prompt = 1;
50 bool	enterhist = 0;
51 static time_t chktim;
52 char	*err_msg;	/* Error message from scanner/parser */
53 
54 extern	gid_t getegid(), getgid();
55 extern	uid_t geteuid(), getuid();
56 extern tchar **strblktotsblk(/* char **, int */);
57 
58 extern void hupforegnd(void);
59 void interactive_hup(void);
60 void interactive_login_hup(void);
61 
62 void	importpath(tchar *);
63 void	srccat(tchar *, tchar *);
64 void	srccat_inlogin(tchar *, tchar *);
65 void	srcunit(int, bool, bool);
66 void	rechist(void);
67 void	goodbye(void);
68 void	pintr1(bool);
69 void	process(bool);
70 void	dosource(tchar **);
71 void	mailchk(void);
72 void	printprompt(void);
73 void	sigwaiting(void);
74 void	siglwp(void);
75 void	initdesc(int, char *[]);
76 void	initdesc_x(int, char *[], int);
77 void	closem(void);
78 void	unsetfd(int);
79 void	phup(void);
80 
81 #ifdef	TRACE
82 FILE *trace;
83 /*
84  * Trace routines
85  */
86 #define	TRACEFILE	"/tmp/trace.XXXXXX"
87 
88 /*
89  * Initialize trace file.
90  * Called from main.
91  */
92 void
93 trace_init(void)
94 {
95 	char name[128];
96 	char *p;
97 
98 	strcpy(name, TRACEFILE);
99 	p = mktemp(name);
100 	trace = fopen(p, "w");
101 }
102 
103 /*
104  * write message to trace file
105  */
106 /*VARARGS1*/
107 void
108 tprintf(fmt, a, b, c, d, e, f, g, h, i, j)
109 	char *fmt;
110 {
111 	if (trace) {
112 		fprintf(trace, fmt, a, b, c, d, e, f, g, h, i, j);
113 		fflush(trace);
114 	}
115 }
116 #endif
117 
118 int
119 main(int c, char **av)
120 {
121 	tchar **v, *cp, *r;
122 	int f;
123 	struct sigvec osv;
124 	struct sigaction sa;
125 	tchar s_prompt[MAXHOSTNAMELEN+3];
126 	char *c_max_var_len;
127 	int c_max_var_len_size;
128 	bool intact = 0;
129 
130 	/*
131 	 * set up the error exit, if there is an error before
132 	 * this is done, it will core dump, and we don't
133 	 * tolerate core dumps
134 	 */
135 	haderr = 0;
136 	setexit();
137 	if (haderr) {
138 		/*
139 		 *  if were here, there was an error in the csh
140 		 *  startup so just punt
141 		 */
142 		printf("csh startup error, csh exiting...\n");
143 		flush();
144 		exitstat();
145 	}
146 
147 
148 	(void) setlocale(LC_ALL, "");
149 #if !defined(TEXT_DOMAIN)	/* Should be defined by cc -D */
150 #define	TEXT_DOMAIN "SYS_TEST"	/* Use this only if it weren't */
151 #endif
152 	(void) textdomain(TEXT_DOMAIN);
153 
154 	/* Copy arguments */
155 	v = strblktotsblk(av, c);
156 
157 	/*
158 	 * Initialize paraml list
159 	 */
160 	paraml.next = paraml.prev = &paraml;
161 
162 	settimes();			/* Immed. estab. timing base */
163 
164 	if (eq(v[0], S_aout /* "a.out" */))	/* A.out's are quittable */
165 		quitit = 1;
166 	uid = getuid();
167 	loginsh = **v == '-';
168 	if (loginsh)
169 		(void) time(&chktim);
170 
171 	/*
172 	 * Move the descriptors to safe places.
173 	 * The variable didfds is 0 while we have only FSH* to work with.
174 	 * When didfds is true, we have 0,1,2 and prefer to use these.
175 	 *
176 	 * Also, setup data for csh internal file descriptor book keeping.
177 	 */
178 	initdesc(c, av);
179 
180 	/*
181 	 * Initialize the shell variables.
182 	 * ARGV and PROMPT are initialized later.
183 	 * STATUS is also munged in several places.
184 	 * CHILD is munged when forking/waiting
185 	 */
186 
187 	c_max_var_len_size = snprintf(NULL, 0, "%ld", MAX_VAR_LEN);
188 	c_max_var_len = (char *)xalloc(c_max_var_len_size + 1);
189 	(void) snprintf(c_max_var_len, (c_max_var_len_size + 1),
190 	    "%ld", MAX_VAR_LEN);
191 	set(S_SUNW_VARLEN,  strtots(NOSTR, c_max_var_len));
192 	xfree(c_max_var_len);
193 
194 	/* don't do globbing here, just set exact copies */
195 	setNS(S_noglob);
196 
197 	set(S_status /* "status" */, S_0 /* "0" */);
198 	dinit(cp = getenvs_("HOME"));	/* dinit thinks that HOME==cwd in a */
199 					/* login shell */
200 	if (cp == NOSTR)
201 		fast++;			/* No home -> can't read scripts */
202 	else {
203 		if (strlen_(cp) >= BUFSIZ - 10) {
204 			cp = NOSTR;
205 			fast++;
206 			printf("%s\n", gettext("Pathname too long"));
207 			set(S_home /* "home" */, savestr(cp));
208 			local_setenv(S_HOME, savestr(cp));
209 		}
210 		set(S_home /* "home" */, savestr(cp));
211 	}
212 	/*
213 	 * Grab other useful things from the environment.
214 	 * Should we grab everything??
215 	 */
216 	if ((cp = getenvs_("USER")) != NOSTR)
217 		set(S_user /* "user" */, savestr(cp));
218 	else {
219 		/*
220 		 * If USER is not defined, set it here.
221 		 */
222 		struct passwd *pw;
223 		pw = getpwuid(getuid());
224 
225 		if (pw != NULL) {
226 			set(S_user, strtots((tchar *)0, pw->pw_name));
227 			local_setenv(S_USER, strtots((tchar *)0, pw->pw_name));
228 		} else if (loginsh) { /* Give up setting USER variable. */
229 	printf("Warning: USER environment variable could not be set.\n");
230 		}
231 	}
232 	if ((cp = getenvs_("TERM")) != NOSTR)
233 		set(S_term /* "term" */, savestr(cp));
234 	/*
235 	 * Re-initialize path if set in environment
236 	 */
237 	if ((cp = getenvs_("PATH")) == NOSTR)
238 		set1(S_path /* "path" */, saveblk(pathlist), &shvhed);
239 	else
240 		importpath(cp);
241 	set(S_shell /* "shell" */, S_SHELLPATH);
242 
243 	doldol = putn(getpid());		/* For $$ */
244 
245 	/* restore globbing until the user says otherwise */
246 	unsetv(S_noglob);
247 
248 	/*
249 	 * Record the interrupt states from the parent process.
250 	 * If the parent is non-interruptible our hand must be forced
251 	 * or we (and our children) won't be either.
252 	 * Our children inherit termination from our parent.
253 	 * We catch it only if we are the login shell.
254 	 */
255 		/* parents interruptibility */
256 	(void) sigvec(SIGINT, (struct sigvec *)0, &osv);
257 	parintr = osv.sv_handler;
258 		/* parents terminability */
259 	(void) sigvec(SIGTERM, (struct sigvec *)0, &osv);
260 	parterm = osv.sv_handler;
261 
262 	_signal(SIGLWP, siglwp);
263 	_signal(SIGWAITING, sigwaiting);
264 	if (loginsh) {
265 		(void) signal(SIGHUP, phup);	/* exit processing on HUP */
266 		(void) signal(SIGXCPU, phup);	/* ...and on XCPU */
267 		(void) signal(SIGXFSZ, phup);	/* ...and on XFSZ */
268 	}
269 
270 	/*
271 	 * Process the arguments.
272 	 *
273 	 * Note that processing of -v/-x is actually delayed till after
274 	 * script processing.
275 	 */
276 	c--, v++;
277 	while (c > 0 && (cp = v[0])[0] == '-' && *++cp != '\0' && !batch) {
278 		do switch (*cp++) {
279 
280 		case 'b':		/* -b	Next arg is input file */
281 			batch++;
282 			break;
283 
284 		case 'c':		/* -c	Command input from arg */
285 			if (c == 1)
286 				exit(0);
287 			c--, v++;
288 			arginp = v[0];
289 			prompt = 0;
290 			nofile++;
291 			cflg++;
292 			break;
293 
294 		case 'e':		/* -e	Exit on any error */
295 			exiterr++;
296 			break;
297 
298 		case 'f':		/* -f	Fast start */
299 			fast++;
300 			break;
301 
302 		case 'i':		/* -i	Interactive, even if !intty */
303 			intact++;
304 			nofile++;
305 			break;
306 
307 		case 'n':		/* -n	Don't execute */
308 			noexec++;
309 			break;
310 
311 		case 'q':		/* -q	(Undoc'd) ... die on quit */
312 			quitit = 1;
313 			break;
314 
315 		case 's':		/* -s	Read from std input */
316 			nofile++;
317 			break;
318 
319 		case 't':		/* -t	Read one line from input */
320 			onelflg = 2;
321 			prompt = 0;
322 			nofile++;
323 			break;
324 #ifdef TRACE
325 		case 'T':		/* -T	trace switch on */
326 			trace_init();
327 			break;
328 #endif
329 
330 		case 'v':		/* -v	Echo hist expanded input */
331 			nverbose = 1;			/* ... later */
332 			break;
333 
334 		case 'x':		/* -x	Echo just before execution */
335 			nexececho = 1;			/* ... later */
336 			break;
337 
338 		case 'V':		/* -V	Echo hist expanded input */
339 			setNS(S_verbose /* "verbose" */);	/* NOW! */
340 			break;
341 
342 		case 'X':		/* -X	Echo just before execution */
343 			setNS(S_echo /* "echo" */);		/* NOW! */
344 			break;
345 
346 		} while (*cp);
347 		v++, c--;
348 	}
349 
350 	if (quitit)			/* With all due haste, for debugging */
351 		(void) signal(SIGQUIT, SIG_DFL);
352 
353 	/*
354 	 * Unless prevented by -c, -i, -s, or -t, if there
355 	 * are remaining arguments the first of them is the name
356 	 * of a shell file from which to read commands.
357 	 */
358 	if (!batch && (uid != geteuid() || getgid() != getegid())) {
359 		errno = EACCES;
360 		child++;			/* So this ... */
361 		Perror(S_csh /* "csh" */);	/* ... doesn't return */
362 	}
363 
364 	if (nofile == 0 && c > 0) {
365 		nofile = open_(v[0], 0);
366 		if (nofile < 0) {
367 			child++;		/* So this ... */
368 			Perror(v[0]);		/* ... doesn't return */
369 		}
370 		file = v[0];
371 		SHIN = dmove(nofile, FSHIN);	/* Replace FSHIN */
372 		(void) fcntl(SHIN, F_SETFD, 1);
373 		prompt = 0;
374 		c--, v++;
375 	}
376 
377 	/*
378 	 * Consider input a tty if it really is or we are interactive.
379 	 */
380 	intty = intact || isatty(SHIN);
381 
382 	/*
383 	 * Decide whether we should play with signals or not.
384 	 * If we are explicitly told (via -i, or -) or we are a login
385 	 * shell (arg0 starts with -) or the input and output are both
386 	 * the ttys("csh", or "csh</dev/ttyx>/dev/ttyx")
387 	 * Note that in only the login shell is it likely that parent
388 	 * may have set signals to be ignored
389 	 */
390 	if (loginsh || intact || intty && isatty(SHOUT))
391 		setintr = 1;
392 #ifdef TELL
393 	settell();
394 #endif
395 	/*
396 	 * Save the remaining arguments in argv.
397 	 */
398 	setq(S_argv /* "argv" */, copyblk(v), &shvhed);
399 
400 	/*
401 	 * Set up the prompt.
402 	 */
403 	if (prompt) {
404 		gethostname_(s_prompt, MAXHOSTNAMELEN);
405 		strcat_(s_prompt,
406 		    uid == 0 ? S_SHARPSP /* "# " */ : S_PERSENTSP /* "% " */);
407 		set(S_prompt /* "prompt" */, s_prompt);
408 	}
409 
410 	/*
411 	 * If we are an interactive shell, then start fiddling
412 	 * with the signals; this is a tricky game.
413 	 */
414 	shpgrp = getpgid(0);
415 	opgrp = tpgrp = -1;
416 	if (setintr) {
417 		**av = '-';
418 		if (!quitit)		/* Wary! */
419 			(void) signal(SIGQUIT, SIG_IGN);
420 		(void) signal(SIGINT, pintr);
421 		(void) sigblock(sigmask(SIGINT));
422 		(void) signal(SIGTERM, SIG_IGN);
423 
424 		/*
425 		 * Explicitly terminate foreground jobs and exit if we are
426 		 * interactive shell
427 		 */
428 		if (loginsh) {
429 			(void) signal(SIGHUP, interactive_login_hup);
430 		} else {
431 			(void) signal(SIGHUP, interactive_hup);
432 		}
433 
434 		if (quitit == 0 && arginp == 0) {
435 			(void) signal(SIGTSTP, SIG_IGN);
436 			(void) signal(SIGTTIN, SIG_IGN);
437 			(void) signal(SIGTTOU, SIG_IGN);
438 			/*
439 			 * Wait till in foreground, in case someone
440 			 * stupidly runs
441 			 *	csh &
442 			 * dont want to try to grab away the tty.
443 			 */
444 			if (isatty(FSHDIAG))
445 				f = FSHDIAG;
446 			else if (isatty(FSHOUT))
447 				f = FSHOUT;
448 			else if (isatty(OLDSTD))
449 				f = OLDSTD;
450 			else
451 				f = -1;
452 retry:
453 			if (ioctl(f, TIOCGPGRP,  (char *)&tpgrp) == 0 &&
454 			    tpgrp != -1) {
455 				if (tpgrp != shpgrp) {
456 					void (*old)() = (void (*)())
457 					    signal(SIGTTIN, SIG_DFL);
458 					(void) kill(0, SIGTTIN);
459 					(void) signal(SIGTTIN, old);
460 					goto retry;
461 				}
462 				opgrp = shpgrp;
463 				shpgrp = getpid();
464 				tpgrp = shpgrp;
465 				(void) setpgid(0, shpgrp);
466 				(void) ioctl(f, TIOCSPGRP,  (char *)&shpgrp);
467 				(void) fcntl(dcopy(f, FSHTTY), F_SETFD, 1);
468 			} else {
469 notty:
470 printf("Warning: no access to tty; thus no job control in this shell...\n");
471 				tpgrp = -1;
472 			}
473 		}
474 	}
475 	if (setintr == 0 && parintr == SIG_DFL)
476 		setintr++;
477 
478 	/*
479 	 * Set SIGCHLD handler, making sure that reads restart after it runs.
480 	 */
481 	sigemptyset(&sa.sa_mask);
482 	sa.sa_handler = pchild;
483 	sa.sa_flags = SA_RESTART;
484 	(void) sigaction(SIGCHLD, &sa, (struct sigaction *)NULL);
485 
486 	/*
487 	 * Set an exit here in case of an interrupt or error reading
488 	 * the shell start-up scripts.
489 	 */
490 	setexit();
491 	haderr = 0;		/* In case second time through */
492 	if (!fast && reenter == 0) {
493 		reenter++;
494 
495 		/*
496 		 * If this is a login csh, and /etc/.login exists,
497 		 * source /etc/.login first.
498 		 */
499 		if (loginsh) {
500 			tchar tmp_etc[4+1];	/* strlen("/etc")+1 */
501 			tchar tmp_login[7+1];	/* strlen("/.login")+1 */
502 
503 			strtots(tmp_etc, "/etc");
504 			strtots(tmp_login, "/.login");
505 			srccat_inlogin(tmp_etc, tmp_login);
506 		}
507 
508 		/* Will have value("home") here because set fast if don't */
509 		srccat(value(S_home /* "home" */),
510 		    S_SLADOTcshrc /* "/.cshrc" */);
511 
512 		/* Hash path */
513 		if (!fast && !arginp && !onelflg && !havhash)
514 			dohash(xhash);
515 
516 
517 		/*
518 		 * Reconstruct the history list now, so that it's
519 		 * available from within .login.
520 		 */
521 		dosource(loadhist);
522 		if (loginsh) {
523 			srccat_inlogin(value(S_home /* "home" */),
524 			    S_SLADOTlogin /* "/.login" */);
525 		}
526 
527 		/*
528 		 * To get cdpath hashing $cdpath must have a
529 		 * value, not $CDPATH.  So if after reading
530 		 * the startup files ( .cshrc ), and
531 		 * user has specified a value for cdpath, then
532 		 * cache $cdpath paths. xhash2 is global array
533 		 * for $cdpath caching.
534 		 */
535 		if (!fast && !arginp && !onelflg && !havhash2)
536 				dohash(xhash2);
537 	}
538 
539 	/*
540 	 * Now are ready for the -v and -x flags
541 	 */
542 	if (nverbose)
543 		setNS(S_verbose /* "verbose" */);
544 	if (nexececho)
545 		setNS(S_echo /* "echo" */);
546 
547 	/*
548 	 * All the rest of the world is inside this call.
549 	 * The argument to process indicates whether it should
550 	 * catch "error unwinds".  Thus if we are a interactive shell
551 	 * our call here will never return by being blown past on an error.
552 	 */
553 	process(setintr);
554 
555 	/*
556 	 * Mop-up.
557 	 */
558 	if (loginsh) {
559 		printf("logout\n");
560 		(void) close(SHIN);	/* No need for unsetfd(). */
561 		child++;
562 		goodbye();
563 	}
564 	rechist();
565 	exitstat();
566 }
567 
568 void
569 untty(void)
570 {
571 
572 	if (tpgrp > 0) {
573 		(void) setpgid(0, opgrp);
574 		(void) ioctl(FSHTTY, TIOCSPGRP,  (char *)&opgrp);
575 	}
576 }
577 
578 void
579 importpath(tchar *cp)
580 {
581 	int i = 0;
582 	tchar *dp;
583 	tchar **pv;
584 	int c;
585 	static tchar dot[2] = {'.', 0};
586 
587 	for (dp = cp; *dp; dp++)
588 		if (*dp == ':')
589 			i++;
590 	/*
591 	 * i+2 where i is the number of colons in the path.
592 	 * There are i+1 directories in the path plus we need
593 	 * room for a zero terminator.
594 	 */
595 	pv =  (tchar **)xcalloc((unsigned)(i + 2), sizeof (tchar **));
596 	dp = cp;
597 	i = 0;
598 	if (*dp)
599 	for (;;) {
600 		if ((c = *dp) == ':' || c == 0) {
601 			*dp = 0;
602 			pv[i++] = savestr(*cp ? cp : dot);
603 			if (c) {
604 				cp = dp + 1;
605 				*dp = ':';
606 			} else
607 				break;
608 		}
609 		dp++;
610 	}
611 	pv[i] = 0;
612 	set1(S_path /* "path" */, pv, &shvhed);
613 }
614 
615 /*
616  * Source to the file which is the catenation of the argument names.
617  */
618 void
619 srccat(tchar *cp, tchar *dp)
620 {
621 	tchar *ep = strspl(cp, dp);
622 	int unit = dmove(open_(ep, 0), -1);
623 
624 	(void) fcntl(unit, F_SETFD, 1);
625 	xfree(ep);
626 #ifdef INGRES
627 	srcunit(unit, 0, 0);
628 #else
629 	srcunit(unit, 1, 0);
630 #endif
631 }
632 
633 /*
634  * Source to the file which is the catenation of the argument names.
635  *	This one does not check the ownership.
636  */
637 void
638 srccat_inlogin(tchar *cp, tchar *dp)
639 {
640 	tchar *ep = strspl(cp, dp);
641 	int unit = dmove(open_(ep, 0), -1);
642 
643 	(void) fcntl(unit, F_SETFD, 1);
644 	xfree(ep);
645 	srcunit(unit, 0, 0);
646 }
647 
648 /*
649  * Source to a unit.  If onlyown it must be our file or our group or
650  * we don't chance it.	This occurs on ".cshrc"s and the like.
651  */
652 void
653 srcunit(int unit, bool onlyown, bool hflg)
654 {
655 	/* We have to push down a lot of state here */
656 	/* All this could go into a structure */
657 	int oSHIN = -1, oldintty = intty;
658 	struct whyle *oldwhyl = whyles;
659 	tchar *ogointr = gointr, *oarginp = arginp;
660 	tchar *oevalp = evalp, **oevalvec = evalvec;
661 	int oonelflg = onelflg;
662 	bool oenterhist = enterhist;
663 	tchar OHIST = HIST;
664 #ifdef TELL
665 	bool otell = cantell;
666 #endif
667 	struct Bin saveB;
668 
669 	/* The (few) real local variables */
670 	jmp_buf oldexit;
671 	int reenter, omask;
672 
673 	if (unit < 0)
674 		return;
675 	if (didfds)
676 		donefds();
677 	if (onlyown) {
678 		struct stat stb;
679 
680 		if (fstat(unit, &stb) < 0 ||
681 		    (stb.st_uid != uid && stb.st_gid != getgid())) {
682 			(void) close(unit);
683 			unsetfd(unit);
684 			return;
685 		}
686 	}
687 
688 	/*
689 	 * There is a critical section here while we are pushing down the
690 	 * input stream since we have stuff in different structures.
691 	 * If we weren't careful an interrupt could corrupt SHIN's Bin
692 	 * structure and kill the shell.
693 	 *
694 	 * We could avoid the critical region by grouping all the stuff
695 	 * in a single structure and pointing at it to move it all at
696 	 * once.  This is less efficient globally on many variable references
697 	 * however.
698 	 */
699 	getexit(oldexit);
700 	reenter = 0;
701 	if (setintr)
702 		omask = sigblock(sigmask(SIGINT));
703 	setexit();
704 	reenter++;
705 	if (reenter == 1) {
706 		/* Setup the new values of the state stuff saved above */
707 		copy((char *)&saveB, (char *)&B, sizeof (saveB));
708 		fbuf =  (tchar **) 0;
709 		fseekp = feobp = fblocks = 0;
710 		oSHIN = SHIN, SHIN = unit, arginp = 0, onelflg = 0;
711 		intty = isatty(SHIN), whyles = 0, gointr = 0;
712 		evalvec = 0; evalp = 0;
713 		enterhist = hflg;
714 		if (enterhist)
715 			HIST = '\0';
716 		/*
717 		 * Now if we are allowing commands to be interrupted,
718 		 * we let ourselves be interrupted.
719 		 */
720 		if (setintr)
721 			(void) sigsetmask(omask);
722 #ifdef TELL
723 		settell();
724 #endif
725 		process(0);		/* 0 -> blow away on errors */
726 	}
727 	if (setintr)
728 		(void) sigsetmask(omask);
729 	if (oSHIN >= 0) {
730 		int i;
731 
732 		/* We made it to the new state... free up its storage */
733 		/* This code could get run twice but xfree doesn't care */
734 		for (i = 0; i < fblocks; i++)
735 			xfree(fbuf[i]);
736 		xfree((char *)fbuf);
737 
738 		/* Reset input arena */
739 		copy((char *)&B, (char *)&saveB, sizeof (B));
740 
741 		(void) close(SHIN), SHIN = oSHIN;
742 		unsetfd(SHIN);
743 		arginp = oarginp, onelflg = oonelflg;
744 		evalp = oevalp, evalvec = oevalvec;
745 		intty = oldintty, whyles = oldwhyl, gointr = ogointr;
746 		if (enterhist)
747 			HIST = OHIST;
748 		enterhist = oenterhist;
749 #ifdef TELL
750 		cantell = otell;
751 #endif
752 	}
753 
754 	resexit(oldexit);
755 	/*
756 	 * If process reset() (effectively an unwind) then
757 	 * we must also unwind.
758 	 */
759 	if (reenter >= 2)
760 		error(NULL);
761 }
762 
763 void
764 rechist(void)
765 {
766 	tchar buf[BUFSIZ];
767 	int fp, ftmp, oldidfds;
768 
769 	if (!fast) {
770 		if (value(S_savehist /* "savehist" */)[0] == '\0')
771 			return;
772 		(void) strcpy_(buf, value(S_home /* "home" */));
773 		(void) strcat_(buf, S_SLADOThistory /* "/.history" */);
774 		fp = creat_(buf, 0666);
775 		if (fp == -1)
776 			return;
777 		oldidfds = didfds;
778 		didfds = 0;
779 		ftmp = SHOUT;
780 		SHOUT = fp;
781 		(void) strcpy_(buf, value(S_savehist /* "savehist" */));
782 		dumphist[2] = buf;
783 		dohist(dumphist);
784 		(void) close(fp);
785 		unsetfd(fp);
786 		SHOUT = ftmp;
787 		didfds = oldidfds;
788 	}
789 }
790 
791 void
792 goodbye(void)
793 {
794 	if (loginsh) {
795 		(void) signal(SIGQUIT, SIG_IGN);
796 		(void) signal(SIGINT, SIG_IGN);
797 		(void) signal(SIGTERM, SIG_IGN);
798 		setintr = 0;		/* No interrupts after "logout" */
799 		if (adrof(S_home /* "home" */))
800 			srccat(value(S_home /* "home" */),
801 			    S_SLADOTlogout /* "/.logout" */);
802 	}
803 	rechist();
804 	exitstat();
805 }
806 
807 void
808 exitstat(void)
809 {
810 
811 #ifdef PROF
812 	monitor(0);
813 #endif
814 	/*
815 	 * Note that if STATUS is corrupted (i.e. getn bombs)
816 	 * then error will exit directly because we poke child here.
817 	 * Otherwise we might continue unwarrantedly (sic).
818 	 */
819 	child++;
820 	untty();
821 	exit(getn(value(S_status /* "status" */)));
822 }
823 
824 /*
825  * in the event of a HUP we want to save the history
826  */
827 void
828 phup(void)
829 {
830 	rechist();
831 	exit(1);
832 }
833 
834 void
835 interactive_hup(void)
836 {
837 	hupforegnd();
838 	exit(1);
839 }
840 
841 void
842 interactive_login_hup(void)
843 {
844 	rechist();
845 	hupforegnd();
846 	exit(1);
847 }
848 
849 tchar *jobargv[2] = { S_jobs /* "jobs" */, 0 };
850 /*
851  * Catch an interrupt, e.g. during lexical input.
852  * If we are an interactive shell, we reset the interrupt catch
853  * immediately.  In any case we drain the shell output,
854  * and finally go through the normal error mechanism, which
855  * gets a chance to make the shell go away.
856  */
857 void
858 pintr(void)
859 {
860 	pintr1(1);
861 }
862 
863 void
864 pintr1(bool wantnl)
865 {
866 	tchar **v;
867 	int omask;
868 
869 	omask = sigblock(0);
870 	if (setintr) {
871 		(void) sigsetmask(omask & ~sigmask(SIGINT));
872 		if (pjobs) {
873 			pjobs = 0;
874 			printf("\n");
875 			dojobs(jobargv);
876 			bferr("Interrupted");
877 		}
878 	}
879 	(void) sigsetmask(omask & ~sigmask(SIGCHLD));
880 	draino();
881 
882 	/*
883 	 * If we have an active "onintr" then we search for the label.
884 	 * Note that if one does "onintr -" then we shan't be interruptible
885 	 * so we needn't worry about that here.
886 	 */
887 	if (gointr) {
888 		search(ZGOTO, 0, gointr);
889 		if (v = pargv)
890 			pargv = 0, blkfree(v);
891 		if (v = gargv)
892 			gargv = 0, blkfree(v);
893 		reset();
894 	} else if (intty && wantnl)
895 		printf("\n");		/* Some like this, others don't */
896 	error(NULL);
897 }
898 
899 /*
900  * Process is the main driving routine for the shell.
901  * It runs all command processing, except for those within { ... }
902  * in expressions (which is run by a routine evalav in sh.exp.c which
903  * is a stripped down process), and `...` evaluation which is run
904  * also by a subset of this code in sh.glob.c in the routine backeval.
905  *
906  * The code here is a little strange because part of it is interruptible
907  * and hence freeing of structures appears to occur when none is necessary
908  * if this is ignored.
909  *
910  * Note that if catch is not set then we will unwind on any error.
911  * If an end-of-file occurs, we return.
912  */
913 void
914 process(bool catch)
915 {
916 	jmp_buf osetexit;
917 	struct command *t;
918 
919 	getexit(osetexit);
920 	for (;;) {
921 		pendjob();
922 		freelex(&paraml);
923 		paraml.next = paraml.prev = &paraml;
924 		paraml.word = S_ /* "" */;
925 		t = 0;
926 		setexit();
927 		justpr = enterhist;	/* execute if not entering history */
928 
929 		/*
930 		 * Interruptible during interactive reads
931 		 */
932 		if (setintr)
933 			(void) sigsetmask(sigblock(0) & ~sigmask(SIGINT));
934 
935 		/*
936 		 * For the sake of reset()
937 		 */
938 		freelex(&paraml), freesyn(t), t = 0;
939 
940 		if (haderr) {
941 			if (!catch) {
942 				/* unwind */
943 				doneinp = 0;
944 				resexit(osetexit);
945 				reset();
946 			}
947 			haderr = 0;
948 			/*
949 			 * Every error is eventually caught here or
950 			 * the shell dies.  It is at this
951 			 * point that we clean up any left-over open
952 			 * files, by closing all but a fixed number
953 			 * of pre-defined files.  Thus routines don't
954 			 * have to worry about leaving files open due
955 			 * to deeper errors... they will get closed here.
956 			 */
957 			closem();
958 			continue;
959 		}
960 		if (doneinp) {
961 			doneinp = 0;
962 			break;
963 		}
964 		if (chkstop)
965 			chkstop--;
966 		if (neednote)
967 			pnote();
968 		if (intty && prompt && evalvec == 0) {
969 			mailchk();
970 			/*
971 			 * If we are at the end of the input buffer
972 			 * then we are going to read fresh stuff.
973 			 * Otherwise, we are rereading input and don't
974 			 * need or want to prompt.
975 			 */
976 			if (fseekp == feobp)
977 				printprompt();
978 		}
979 		err_msg = NULL;
980 
981 		/*
982 		 * Echo not only on VERBOSE, but also with history expansion.
983 		 */
984 		if (lex(&paraml) && intty ||
985 		    adrof(S_verbose /* "verbose" */)) {
986 			haderr = 1;
987 			prlex(&paraml);
988 			haderr = 0;
989 		}
990 
991 		/*
992 		 * The parser may lose space if interrupted.
993 		 */
994 		if (setintr)
995 			(void) sigblock(sigmask(SIGINT));
996 
997 		/*
998 		 * Save input text on the history list if
999 		 * reading in old history, or it
1000 		 * is from the terminal at the top level and not
1001 		 * in a loop.
1002 		 */
1003 		if (enterhist || catch && intty && !whyles)
1004 			savehist(&paraml);
1005 
1006 		/*
1007 		 * Print lexical error messages, except when sourcing
1008 		 * history lists.
1009 		 */
1010 		if (!enterhist && err_msg)
1011 			error("%s", gettext(err_msg));
1012 
1013 		/*
1014 		 * If had a history command :p modifier then
1015 		 * this is as far as we should go
1016 		 */
1017 		if (justpr)
1018 			reset();
1019 
1020 		alias(&paraml);
1021 
1022 		/*
1023 		 * Parse the words of the input into a parse tree.
1024 		 */
1025 		t = syntax(paraml.next, &paraml, 0);
1026 		if (err_msg)
1027 			error("%s", gettext(err_msg));
1028 
1029 		/*
1030 		 * Execute the parse tree
1031 		 */
1032 		{
1033 			/*
1034 			 * POSIX requires SIGCHLD to be held
1035 			 * until all processes have joined the
1036 			 * process group in order to avoid race
1037 			 * condition.
1038 			 */
1039 			int omask;
1040 
1041 			omask = sigblock(sigmask(SIGCHLD));
1042 			execute(t, tpgrp);
1043 			(void) sigsetmask(omask &~ sigmask(SIGCHLD));
1044 		}
1045 
1046 		if (err_msg)
1047 			error("%s", gettext(err_msg));
1048 		/*
1049 		 * Made it!
1050 		 */
1051 		freelex(&paraml), freesyn(t);
1052 	}
1053 	resexit(osetexit);
1054 }
1055 
1056 void
1057 dosource(tchar **t)
1058 {
1059 	tchar *f;
1060 	int u;
1061 	bool hflg = 0;
1062 	tchar buf[BUFSIZ];
1063 
1064 	t++;
1065 	if (*t && eq(*t, S_h /* "-h" */)) {
1066 		if (*++t == NOSTR)
1067 			bferr("Too few arguments.");
1068 		hflg++;
1069 	}
1070 	(void) strcpy_(buf, *t);
1071 	f = globone(buf);
1072 	u = dmove(open_(f, 0), -1);
1073 	xfree(f);
1074 	freelex(&paraml);
1075 	if (u < 0 && !hflg)
1076 		Perror(f);
1077 	(void) fcntl(u, F_SETFD, 1);
1078 	srcunit(u, 0, hflg);
1079 }
1080 
1081 /*
1082  * Check for mail.
1083  * If we are a login shell, then we don't want to tell
1084  * about any mail file unless its been modified
1085  * after the time we started.
1086  * This prevents us from telling the user things they already
1087  * know, since the login program insists on saying
1088  * "You have mail."
1089  */
1090 void
1091 mailchk(void)
1092 {
1093 	struct varent *v;
1094 	tchar **vp;
1095 	time_t t;
1096 	int intvl, cnt;
1097 	struct stat stb;
1098 	bool new;
1099 
1100 	v = adrof(S_mail /* "mail" */);
1101 	if (v == 0)
1102 		return;
1103 	(void) time(&t);
1104 	vp = v->vec;
1105 	cnt = blklen(vp);
1106 	intvl = (cnt && number(*vp)) ? (--cnt, getn(*vp++)) : MAILINTVL;
1107 	if (intvl < 1)
1108 		intvl = 1;
1109 	if (chktim + intvl > t)
1110 		return;
1111 	for (; *vp; vp++) {
1112 		if (stat_(*vp, &stb) < 0)
1113 			continue;
1114 		new = stb.st_mtime > time0.tv_sec;
1115 		if (stb.st_size == 0 || stb.st_atime >= stb.st_mtime ||
1116 		    (stb.st_atime <= chktim && stb.st_mtime <= chktim) ||
1117 		    loginsh && !new)
1118 			continue;
1119 		if (cnt == 1)
1120 			printf("You have %smail.\n", new ? "new " : "");
1121 		else
1122 			printf("%s in %t.\n", new ? "New mail" : "Mail", *vp);
1123 	}
1124 	chktim = t;
1125 }
1126 
1127 /*
1128  * Extract a home directory from the password file
1129  * The argument points to a buffer where the name of the
1130  * user whose home directory is sought is currently.
1131  * We write the home directory of the user back there.
1132  */
1133 int
1134 gethdir(tchar *home)
1135 {
1136 	/* getpwname will not be modified, so we need temp. buffer */
1137 	char home_str[BUFSIZ];
1138 	tchar home_ts[BUFSIZ];
1139 	struct passwd *pp /* = getpwnam(home) */;
1140 
1141 	pp = getpwnam(tstostr(home_str, home));
1142 	if (pp == 0)
1143 		return (1);
1144 	(void) strcpy_(home, strtots(home_ts, pp->pw_dir));
1145 	return (0);
1146 }
1147 
1148 
1149 #if 0
1150 void
1151 #ifdef PROF
1152 done(int i)
1153 #else
1154 exit(int i)
1155 #endif
1156 {
1157 
1158 	untty();
1159 	_exit(i);
1160 }
1161 #endif
1162 
1163 void
1164 printprompt(void)
1165 {
1166 	tchar *cp;
1167 
1168 	if (!whyles) {
1169 		/*
1170 		 * Print the prompt string
1171 		 */
1172 		for (cp = value(S_prompt /* "prompt" */); *cp; cp++)
1173 			if (*cp == HIST)
1174 				printf("%d", eventno + 1);
1175 			else {
1176 				if (*cp == '\\' && cp[1] == HIST)
1177 					cp++;
1178 				Putchar(*cp | QUOTE);
1179 			}
1180 	} else
1181 		/*
1182 		 * Prompt for forward reading loop
1183 		 * body content.
1184 		 */
1185 		printf("? ");
1186 	flush();
1187 }
1188 
1189 /*
1190  * Save char * block.
1191  */
1192 tchar **
1193 strblktotsblk(char **v, int num)
1194 {
1195 	tchar **newv =
1196 	    (tchar **)xcalloc((unsigned)(num+ 1), sizeof (tchar **));
1197 	tchar **onewv = newv;
1198 
1199 	while (*v && num--)
1200 		*newv++ = strtots(NOSTR, *v++);
1201 	*newv = 0;
1202 	return (onewv);
1203 }
1204 
1205 void
1206 sigwaiting(void)
1207 {
1208 	_signal(SIGWAITING, sigwaiting);
1209 }
1210 
1211 void
1212 siglwp(void)
1213 {
1214 	_signal(SIGLWP, siglwp);
1215 }
1216 
1217 
1218 /*
1219  * Following functions and data are used for csh to do its
1220  * file descriptors book keeping.
1221  */
1222 
1223 static int *fdinuse = NULL;	/* The list of files opened by csh */
1224 static int nbytesused = 0;	/* no of bytes allocated to fdinuse */
1225 static int max_fd = 0;		/* The maximum descriptor in fdinuse */
1226 static int my_pid;		/* The process id set in initdesc() */
1227 static int NoFile = NOFILE;	/* The number of files I can use. */
1228 
1229 /*
1230  * Get the number of files this csh can use.
1231  *
1232  * Move the initial descriptors to their eventual
1233  * resting places, closing all other units.
1234  *
1235  * Also, reserve 0/1/2, so NIS+ routines do not get
1236  * hold of them. And initialize fdinuse list and set
1237  * the current process id.
1238  *
1239  * If this csh was invoked from setuid'ed script file,
1240  * do not close the third argument passed. The file
1241  * must be one of /dev/fd/0,1,2,,,
1242  *	(execv() always passes three arguments when it execs a script
1243  *	 file in a form of #! /bin/csh -b.)
1244  *
1245  * If is_reinit is set in initdesc_x(), then we only close the file
1246  * descriptors that we actually opened (as recorded in fdinuse).
1247  */
1248 void
1249 initdesc(int argc, char *argv[])
1250 {
1251 	initdesc_x(argc, argv, 0);
1252 }
1253 
1254 void
1255 reinitdesc(int argc, char *argv[])
1256 {
1257 	initdesc_x(argc, argv, 1);
1258 }
1259 
1260 /*
1261  * Callback functions for closing all file descriptors.
1262  */
1263 static int
1264 close_except(void *cd, int fd)
1265 {
1266 	int script_fd = *(int *)cd;
1267 
1268 	if (fd >= 3 && fd < NoFile && fd != script_fd)
1269 		(void) close(fd);
1270 	return (0);
1271 }
1272 
1273 static int
1274 close_inuse(void *cd, int fd)
1275 {
1276 	int script_fd = *(int *)cd;
1277 
1278 	if (fd >= 3 && fd < NoFile && fd != script_fd &&
1279 	    CSH_FD_ISSET(fd, fdinuse)) {
1280 		(void) close(fd);
1281 		unsetfd(fd);
1282 	}
1283 	return (0);
1284 }
1285 
1286 void
1287 initdesc_x(int argc, char *argv[], int is_reinit)
1288 {
1289 
1290 	int script_fd = -1;
1291 	struct stat buf;
1292 	struct rlimit rlp;
1293 
1294 	/*
1295 	 * Get pid of this shell
1296 	 */
1297 	my_pid = getpid();
1298 
1299 	/*
1300 	 * Get the hard limit numbers of descriptors
1301 	 * this csh can use.
1302 	 */
1303 	if (getrlimit(RLIMIT_NOFILE, &rlp) == 0)
1304 		NoFile = rlp.rlim_cur;
1305 
1306 	/*
1307 	 * If this csh was invoked for executing setuid script file,
1308 	 * the third argument passed is the special file name
1309 	 * which should not be closed.  This special file name is
1310 	 * in the form /dev/fd/X.
1311 	 */
1312 	if (argc >= 3)
1313 		if (sscanf(argv[2], "/dev/fd/%d", &script_fd) != 1)
1314 			script_fd = -1;
1315 		else
1316 			/* Make sure to close this file on exec.  */
1317 			fcntl(script_fd, F_SETFD, 1);
1318 
1319 	if (fdinuse == NULL) {
1320 		nbytesused = sizeof (int) *
1321 		    howmany(NoFile, sizeof (int) * NBBY);
1322 		fdinuse = (int *)xalloc(nbytesused);
1323 	}
1324 
1325 	/*
1326 	 * Close all files except 0/1/2 to get a clean
1327 	 * file descritor space.
1328 	 */
1329 	if (!is_reinit)
1330 		(void) fdwalk(close_except, &script_fd);
1331 	else
1332 		(void) fdwalk(close_inuse, &script_fd);
1333 
1334 	didfds = 0;			/* 0, 1, 2 aren't set up */
1335 
1336 	if (fstat(0, &buf) < 0)
1337 		open("/dev/null", 0);
1338 
1339 	(void) fcntl(SHIN = dcopy(0, FSHIN), F_SETFD,  1);
1340 	(void) fcntl(SHOUT = dcopy(1, FSHOUT), F_SETFD,  1);
1341 	(void) fcntl(SHDIAG = dcopy(2, FSHDIAG), F_SETFD,  1);
1342 	(void) fcntl(OLDSTD = dcopy(SHIN, FOLDSTD), F_SETFD,  1);
1343 
1344 	/*
1345 	 * Open 0/1/2 to avoid Nis+ functions to pick them up.
1346 	 *	Now, 0/1/2 are saved, close them and open them.
1347 	 */
1348 	close(0); close(1); close(2);
1349 	open("/dev/null", 0);
1350 	dup(0);
1351 	dup(0);
1352 
1353 	/*
1354 	 * Clear fd_set mask
1355 	 */
1356 	if (!is_reinit)
1357 		CSH_FD_ZERO(fdinuse, nbytesused);
1358 }
1359 
1360 /*
1361  * This routine is called after an error to close up
1362  * any units which may have been left open accidentally.
1363  *
1364  * You only need to remove files in fdinuse list.
1365  * After you have removed the files, you can clear the
1366  * list and max_fd.
1367  */
1368 void
1369 closem(void)
1370 {
1371 	int f;
1372 
1373 	for (f = 3; f <= max_fd; f++) {
1374 		if (CSH_FD_ISSET(f, fdinuse) &&
1375 		    f != SHIN && f != SHOUT && f != SHDIAG &&
1376 		    f != OLDSTD && f != FSHTTY)
1377 			close(f);
1378 	}
1379 	CSH_FD_ZERO(fdinuse, nbytesused);
1380 	max_fd = 0;
1381 }
1382 
1383 /*
1384  * Reset my_pid when a new process is created.  Only call this
1385  * if you want the process to affect fdinuse (e.g., fork, but
1386  * not vfork).
1387  */
1388 void
1389 new_process(void)
1390 {
1391 	my_pid = getpid();
1392 }
1393 
1394 
1395 /*
1396  * Whenever Csh open/create/dup/pipe a file or files,
1397  * Csh keeps track of its open files. The open files
1398  * are kept in "fdinuse, Fd In Use" list.
1399  *
1400  * When a file descriptor is newly allocated, setfd() is
1401  * used to mark the fact in "fdinuse" list.
1402  *	For example,
1403  *		fd = open("newfile", 0);
1404  *		setfd(fd);
1405  *
1406  * When a file is freed by close() function, unsetfd() is
1407  * used to remove the fd from "fdinuse" list.
1408  *	For example,
1409  *		close(fd);
1410  *		unsetfd(fd);
1411  */
1412 void
1413 setfd(int fd)
1414 {
1415 	/*
1416 	 * Because you want to avoid
1417 	 * conflict due to vfork().
1418 	 */
1419 	if (my_pid != getpid())
1420 		return;
1421 
1422 	if (fd >= NoFile || fd < 0)
1423 		return;
1424 
1425 	if (fd > max_fd)
1426 		max_fd = fd;
1427 	CSH_FD_SET(fd, fdinuse);
1428 }
1429 
1430 void
1431 unsetfd(int fd)
1432 {
1433 	int i;
1434 
1435 	/*
1436 	 * Because you want to avoid
1437 	 * conflict due to vfork().
1438 	 */
1439 	if (my_pid != getpid())
1440 		return;
1441 
1442 	if (fd >= NoFile || fd < 0)
1443 		return;
1444 
1445 	CSH_FD_CLR(fd, fdinuse);
1446 	if (fd == max_fd) {
1447 		for (i = max_fd-1; i >= 3; i--)
1448 			if (CSH_FD_ISSET(i, fdinuse)) {
1449 				max_fd = i;
1450 				return;
1451 			}
1452 		max_fd = 0;
1453 	}
1454 }
1455