xref: /openbsd/bin/ksh/main.c (revision d25d28bf)
1 /*	$OpenBSD: main.c,v 1.80 2016/09/08 15:51:54 millert Exp $	*/
2 
3 /*
4  * startup, main loop, environments and error handling
5  */
6 
7 #include <sys/stat.h>
8 
9 #include <errno.h>
10 #include <fcntl.h>
11 #include <paths.h>
12 #include <pwd.h>
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <string.h>
16 #include <unistd.h>
17 
18 #include "sh.h"
19 
20 extern char **environ;
21 
22 /*
23  * global data
24  */
25 
26 static void	reclaim(void);
27 static void	remove_temps(struct temp *tp);
28 static int	is_restricted(char *name);
29 static void	init_username(void);
30 
31 const char *kshname;
32 pid_t	kshpid;
33 pid_t	procpid;
34 uid_t	ksheuid;
35 int	exstat;
36 int	subst_exstat;
37 const char *safe_prompt;
38 
39 Area	aperm;
40 
41 struct env	*genv;
42 
43 char	shell_flags[FNFLAGS];
44 
45 char	null[] = "";
46 
47 int shl_stdout_ok;
48 
49 unsigned int	ksh_tmout;
50 enum tmout_enum	ksh_tmout_state = TMOUT_EXECUTING;
51 
52 int	really_exit;
53 
54 int ifs0 = ' ';
55 
56 volatile sig_atomic_t	trap;
57 volatile sig_atomic_t	intrsig;
58 volatile sig_atomic_t	fatal_trap;
59 
60 Getopt	builtin_opt;
61 Getopt	user_opt;
62 
63 struct coproc	coproc;
64 sigset_t	sm_default, sm_sigchld;
65 
66 char	*builtin_argv0;
67 int	 builtin_flag;
68 
69 char	*current_wd;
70 int	 current_wd_size;
71 
72 #ifdef EDIT
73 int	x_cols = 80;
74 #endif /* EDIT */
75 
76 /*
77  * shell initialization
78  */
79 
80 static const char initifs[] = "IFS= \t\n";
81 
82 static const char initsubs[] = "${PS2=> } ${PS3=#? } ${PS4=+ }";
83 
84 static const char *initcoms [] = {
85 	"typeset", "-r", "KSH_VERSION", NULL,
86 	"typeset", "-x", "SHELL", "PATH", "HOME", NULL,
87 	"typeset", "-ir", "PPID", NULL,
88 	"typeset", "-i", "OPTIND=1", NULL,
89 	"eval", "typeset -i RANDOM MAILCHECK=\"${MAILCHECK-600}\" SECONDS=\"${SECONDS-0}\" TMOUT=\"${TMOUT-0}\"", NULL,
90 	"alias",
91 	 /* Standard ksh aliases */
92 	  "hash=alias -t",	/* not "alias -t --": hash -r needs to work */
93 	  "type=whence -v",
94 #ifdef JOBS
95 	  "stop=kill -STOP",
96 #endif
97 	  "autoload=typeset -fu",
98 	  "functions=typeset -f",
99 #ifdef HISTORY
100 	  "history=fc -l",
101 #endif /* HISTORY */
102 	  "integer=typeset -i",
103 	  "nohup=nohup ",
104 	  "local=typeset",
105 	  "r=fc -s",
106 	 /* Aliases that are builtin commands in at&t */
107 	  "login=exec login",
108 	  NULL,
109 	/* this is what at&t ksh seems to track, with the addition of emacs */
110 	"alias", "-tU",
111 	  "cat", "cc", "chmod", "cp", "date", "ed", "emacs", "grep", "ls",
112 	  "mail", "make", "mv", "pr", "rm", "sed", "sh", "vi", "who",
113 	  NULL,
114 	NULL
115 };
116 
117 char username[_PW_NAME_LEN + 1];
118 
119 #define version_param  (initcoms[2])
120 
121 /* The shell uses its own variation on argv, to build variables like
122  * $0 and $@.
123  * Allocate a new array since modifying the original argv will modify
124  * ps output.
125  */
126 static char **
127 make_argv(int argc, char *argv[])
128 {
129 	int i;
130 	char **nargv;
131 
132 	nargv = areallocarray(NULL, argc + 1, sizeof(char *), &aperm);
133 	nargv[0] = (char *) kshname;
134 	for (i = 1; i < argc; i++)
135 		nargv[i] = argv[i];
136 	nargv[i] = NULL;
137 
138 	return nargv;
139 }
140 
141 int
142 main(int argc, char *argv[])
143 {
144 	int i;
145 	int argi;
146 	Source *s;
147 	struct block *l;
148 	int restricted, errexit;
149 	char **wp;
150 	struct env env;
151 	pid_t ppid;
152 
153 	kshname = argv[0];
154 
155 	if (pledge("stdio rpath wpath cpath fattr flock getpw proc exec tty",
156 	    NULL) == -1) {
157 		perror("pledge");
158 		exit(1);
159 	}
160 
161 	ainit(&aperm);		/* initialize permanent Area */
162 
163 	/* set up base environment */
164 	memset(&env, 0, sizeof(env));
165 	env.type = E_NONE;
166 	ainit(&env.area);
167 	genv = &env;
168 	newblock();		/* set up global l->vars and l->funs */
169 
170 	/* Do this first so output routines (eg, errorf, shellf) can work */
171 	initio();
172 
173 	initvar();
174 
175 	initctypes();
176 
177 	inittraps();
178 
179 	coproc_init();
180 
181 	/* set up variable and command dictionaries */
182 	ktinit(&taliases, APERM, 0);
183 	ktinit(&aliases, APERM, 0);
184 	ktinit(&homedirs, APERM, 0);
185 
186 	/* define shell keywords */
187 	initkeywords();
188 
189 	/* define built-in commands */
190 	ktinit(&builtins, APERM, 64); /* must be 2^n (currently 40 builtins) */
191 	for (i = 0; shbuiltins[i].name != NULL; i++)
192 		builtin(shbuiltins[i].name, shbuiltins[i].func);
193 	for (i = 0; kshbuiltins[i].name != NULL; i++)
194 		builtin(kshbuiltins[i].name, kshbuiltins[i].func);
195 
196 	init_histvec();
197 
198 	def_path = _PATH_DEFPATH;
199 	{
200 		size_t len = confstr(_CS_PATH, NULL, 0);
201 		char *new;
202 
203 		if (len > 0) {
204 			confstr(_CS_PATH, new = alloc(len + 1, APERM), len + 1);
205 			def_path = new;
206 		}
207 	}
208 
209 	/* Set PATH to def_path (will set the path global variable).
210 	 * (import of environment below will probably change this setting).
211 	 */
212 	{
213 		struct tbl *vp = global("PATH");
214 		/* setstr can't fail here */
215 		setstr(vp, def_path, KSH_RETURN_ERROR);
216 	}
217 
218 
219 	/* Turn on nohup by default for now - will change to off
220 	 * by default once people are aware of its existence
221 	 * (at&t ksh does not have a nohup option - it always sends
222 	 * the hup).
223 	 */
224 	Flag(FNOHUP) = 1;
225 
226 	/* Turn on brace expansion by default.  At&t ksh's that have
227 	 * alternation always have it on.  BUT, posix doesn't have
228 	 * brace expansion, so set this before setting up FPOSIX
229 	 * (change_flag() clears FBRACEEXPAND when FPOSIX is set).
230 	 */
231 #ifdef BRACE_EXPAND
232 	Flag(FBRACEEXPAND) = 1;
233 #endif /* BRACE_EXPAND */
234 
235 	/* set posix flag just before environment so that it will have
236 	 * exactly the same effect as the POSIXLY_CORRECT environment
237 	 * variable.  If this needs to be done sooner to ensure correct posix
238 	 * operation, an initial scan of the environment will also have
239 	 * done sooner.
240 	 */
241 #ifdef POSIXLY_CORRECT
242 	change_flag(FPOSIX, OF_SPECIAL, 1);
243 #endif /* POSIXLY_CORRECT */
244 
245 	/* Check to see if we're /bin/sh. */
246 	if (!strcmp(kshname, "sh") || !strcmp(kshname, "-sh") ||
247 	    (strlen(kshname) >= 3 &&
248 	    !strcmp(&kshname[strlen(kshname) - 3], "/sh"))) {
249 		Flag(FSH) = 1;
250 		version_param = "SH_VERSION";
251 	}
252 
253 	/* Set edit mode to emacs by default, may be overridden
254 	 * by the environment or the user.  Also, we want tab completion
255 	 * on in vi by default. */
256 #if defined(EDIT) && defined(EMACS)
257 	change_flag(FEMACS, OF_SPECIAL, 1);
258 #endif /* EDIT && EMACS */
259 #if defined(EDIT) && defined(VI)
260 	Flag(FVITABCOMPLETE) = 1;
261 #endif /* EDIT && VI */
262 
263 	/* import environment */
264 	if (environ != NULL)
265 		for (wp = environ; *wp != NULL; wp++)
266 			typeset(*wp, IMPORT|EXPORT, 0, 0, 0);
267 
268 	kshpid = procpid = getpid();
269 	typeset(initifs, 0, 0, 0, 0);	/* for security */
270 
271 	/* assign default shell variable values */
272 	substitute(initsubs, 0);
273 
274 	/* Figure out the current working directory and set $PWD */
275 	{
276 		struct stat s_pwd, s_dot;
277 		struct tbl *pwd_v = global("PWD");
278 		char *pwd = str_val(pwd_v);
279 		char *pwdx = pwd;
280 
281 		/* Try to use existing $PWD if it is valid */
282 		if (pwd[0] != '/' ||
283 		    stat(pwd, &s_pwd) < 0 || stat(".", &s_dot) < 0 ||
284 		    s_pwd.st_dev != s_dot.st_dev ||
285 		    s_pwd.st_ino != s_dot.st_ino)
286 			pwdx = NULL;
287 		set_current_wd(pwdx);
288 		if (current_wd[0])
289 			simplify_path(current_wd);
290 		/* Only set pwd if we know where we are or if it had a
291 		 * bogus value
292 		 */
293 		if (current_wd[0] || pwd != null)
294 			/* setstr can't fail here */
295 			setstr(pwd_v, current_wd, KSH_RETURN_ERROR);
296 	}
297 	ppid = getppid();
298 	setint(global("PPID"), (long) ppid);
299 	/* setstr can't fail here */
300 	setstr(global(version_param), ksh_version, KSH_RETURN_ERROR);
301 
302 	/* execute initialization statements */
303 	for (wp = (char**) initcoms; *wp != NULL; wp++) {
304 		shcomexec(wp);
305 		for (; *wp != NULL; wp++)
306 			;
307 	}
308 
309 
310 	ksheuid = geteuid();
311 	init_username();
312 	safe_prompt = ksheuid ? "$ " : "# ";
313 	{
314 		struct tbl *vp = global("PS1");
315 
316 		/* Set PS1 if it isn't set, or we are root and prompt doesn't
317 		 * contain a # or \$ (only in ksh mode).
318 		 */
319 		if (!(vp->flag & ISSET) ||
320 		    (!ksheuid && !strchr(str_val(vp), '#') &&
321 		    (Flag(FSH) || !strstr(str_val(vp), "\\$"))))
322 			/* setstr can't fail here */
323 			setstr(vp, safe_prompt, KSH_RETURN_ERROR);
324 	}
325 
326 	/* Set this before parsing arguments */
327 	Flag(FPRIVILEGED) = getuid() != ksheuid || getgid() != getegid();
328 
329 	/* this to note if monitor is set on command line (see below) */
330 	Flag(FMONITOR) = 127;
331 	argi = parse_args(argv, OF_CMDLINE, NULL);
332 	if (argi < 0)
333 		exit(1);
334 
335 	if (Flag(FCOMMAND)) {
336 		s = pushs(SSTRING, ATEMP);
337 		if (!(s->start = s->str = argv[argi++]))
338 			errorf("-c requires an argument");
339 		if (argv[argi])
340 			kshname = argv[argi++];
341 	} else if (argi < argc && !Flag(FSTDIN)) {
342 		s = pushs(SFILE, ATEMP);
343 		s->file = argv[argi++];
344 		s->u.shf = shf_open(s->file, O_RDONLY, 0, SHF_MAPHI|SHF_CLEXEC);
345 		if (s->u.shf == NULL) {
346 			exstat = 127; /* POSIX */
347 			errorf("%s: %s", s->file, strerror(errno));
348 		}
349 		kshname = s->file;
350 	} else {
351 		Flag(FSTDIN) = 1;
352 		s = pushs(SSTDIN, ATEMP);
353 		s->file = "<stdin>";
354 		s->u.shf = shf_fdopen(0, SHF_RD | can_seek(0), NULL);
355 		if (isatty(0) && isatty(2)) {
356 			Flag(FTALKING) = Flag(FTALKING_I) = 1;
357 			/* The following only if isatty(0) */
358 			s->flags |= SF_TTY;
359 			s->u.shf->flags |= SHF_INTERRUPT;
360 			s->file = NULL;
361 		}
362 	}
363 
364 	/* This bizarreness is mandated by POSIX */
365 	{
366 		struct stat s_stdin;
367 
368 		if (fstat(0, &s_stdin) >= 0 && S_ISCHR(s_stdin.st_mode) &&
369 		    Flag(FTALKING))
370 			reset_nonblock(0);
371 	}
372 
373 	/* initialize job control */
374 	i = Flag(FMONITOR) != 127;
375 	Flag(FMONITOR) = 0;
376 	j_init(i);
377 #ifdef EDIT
378 	/* Do this after j_init(), as tty_fd is not initialized 'til then */
379 	if (Flag(FTALKING))
380 		x_init();
381 #endif
382 
383 	l = genv->loc;
384 	l->argv = make_argv(argc - (argi - 1), &argv[argi - 1]);
385 	l->argc = argc - argi;
386 	getopts_reset(1);
387 
388 	/* Disable during .profile/ENV reading */
389 	restricted = Flag(FRESTRICTED);
390 	Flag(FRESTRICTED) = 0;
391 	errexit = Flag(FERREXIT);
392 	Flag(FERREXIT) = 0;
393 
394 	/* Do this before profile/$ENV so that if it causes problems in them,
395 	 * user will know why things broke.
396 	 */
397 	if (!current_wd[0] && Flag(FTALKING))
398 		warningf(false, "Cannot determine current working directory");
399 
400 	if (Flag(FLOGIN)) {
401 		include(KSH_SYSTEM_PROFILE, 0, NULL, 1);
402 		if (!Flag(FPRIVILEGED))
403 			include(substitute("$HOME/.profile", 0), 0, NULL, 1);
404 	}
405 
406 	if (Flag(FPRIVILEGED))
407 		include("/etc/suid_profile", 0, NULL, 1);
408 	else if (Flag(FTALKING)) {
409 		char *env_file;
410 
411 		/* include $ENV */
412 		env_file = str_val(global("ENV"));
413 
414 #ifdef DEFAULT_ENV
415 		/* If env isn't set, include default environment */
416 		if (env_file == null)
417 			env_file = DEFAULT_ENV;
418 #endif /* DEFAULT_ENV */
419 		env_file = substitute(env_file, DOTILDE);
420 		if (*env_file != '\0')
421 			include(env_file, 0, NULL, 1);
422 	}
423 
424 	if (is_restricted(argv[0]) || is_restricted(str_val(global("SHELL"))))
425 		restricted = 1;
426 	if (restricted) {
427 		static const char *const restr_com[] = {
428 			"typeset", "-r", "PATH",
429 			"ENV", "SHELL",
430 			NULL
431 		};
432 		shcomexec((char **) restr_com);
433 		/* After typeset command... */
434 		Flag(FRESTRICTED) = 1;
435 	}
436 	if (errexit)
437 		Flag(FERREXIT) = 1;
438 
439 	if (Flag(FTALKING)) {
440 		hist_init(s);
441 		alarm_init();
442 	} else
443 		Flag(FTRACKALL) = 1;	/* set after ENV */
444 
445 	shell(s, true);	/* doesn't return */
446 	return 0;
447 }
448 
449 static void
450 init_username(void)
451 {
452 	char *p;
453 	struct tbl *vp = global("USER");
454 
455 	if (vp->flag & ISSET)
456 		p = ksheuid == 0 ? "root" : str_val(vp);
457 	else
458 		p = getlogin();
459 
460 	strlcpy(username, p != NULL ? p : "?", sizeof username);
461 }
462 
463 int
464 include(const char *name, int argc, char **argv, int intr_ok)
465 {
466 	Source *volatile s = NULL;
467 	struct shf *shf;
468 	char **volatile old_argv;
469 	volatile int old_argc;
470 	int i;
471 
472 	shf = shf_open(name, O_RDONLY, 0, SHF_MAPHI|SHF_CLEXEC);
473 	if (shf == NULL)
474 		return -1;
475 
476 	if (argv) {
477 		old_argv = genv->loc->argv;
478 		old_argc = genv->loc->argc;
479 	} else {
480 		old_argv = NULL;
481 		old_argc = 0;
482 	}
483 	newenv(E_INCL);
484 	i = sigsetjmp(genv->jbuf, 0);
485 	if (i) {
486 		quitenv(s ? s->u.shf : NULL);
487 		if (old_argv) {
488 			genv->loc->argv = old_argv;
489 			genv->loc->argc = old_argc;
490 		}
491 		switch (i) {
492 		case LRETURN:
493 		case LERROR:
494 			return exstat & 0xff; /* see below */
495 		case LINTR:
496 			/* intr_ok is set if we are including .profile or $ENV.
497 			 * If user ^C's out, we don't want to kill the shell...
498 			 */
499 			if (intr_ok && (exstat - 128) != SIGTERM)
500 				return 1;
501 			/* FALLTHROUGH */
502 		case LEXIT:
503 		case LLEAVE:
504 		case LSHELL:
505 			unwind(i);
506 			/* NOTREACHED */
507 		default:
508 			internal_errorf(1, "include: %d", i);
509 			/* NOTREACHED */
510 		}
511 	}
512 	if (argv) {
513 		genv->loc->argv = argv;
514 		genv->loc->argc = argc;
515 	}
516 	s = pushs(SFILE, ATEMP);
517 	s->u.shf = shf;
518 	s->file = str_save(name, ATEMP);
519 	i = shell(s, false);
520 	quitenv(s->u.shf);
521 	if (old_argv) {
522 		genv->loc->argv = old_argv;
523 		genv->loc->argc = old_argc;
524 	}
525 	return i & 0xff;	/* & 0xff to ensure value not -1 */
526 }
527 
528 /*
529  * spawn a command into a shell optionally keeping track of line
530  * number.
531  */
532 int
533 command(const char *comm, int line)
534 {
535 	Source *s;
536 
537 	s = pushs(SSTRING, ATEMP);
538 	s->start = s->str = comm;
539 	s->line = line;
540 	return shell(s, false);
541 }
542 
543 /*
544  * run the commands from the input source, returning status.
545  */
546 int
547 shell(Source *volatile s, volatile int toplevel)
548 {
549 	struct op *t;
550 	volatile int wastty = s->flags & SF_TTY;
551 	volatile int attempts = 13;
552 	volatile int interactive = Flag(FTALKING) && toplevel;
553 	Source *volatile old_source = source;
554 	int i;
555 
556 	newenv(E_PARSE);
557 	if (interactive)
558 		really_exit = 0;
559 	i = sigsetjmp(genv->jbuf, 0);
560 	if (i) {
561 		switch (i) {
562 		case LINTR: /* we get here if SIGINT not caught or ignored */
563 		case LERROR:
564 		case LSHELL:
565 			if (interactive) {
566 				if (i == LINTR)
567 					shellf("\n");
568 				/* Reset any eof that was read as part of a
569 				 * multiline command.
570 				 */
571 				if (Flag(FIGNOREEOF) && s->type == SEOF &&
572 				    wastty)
573 					s->type = SSTDIN;
574 				/* Used by exit command to get back to
575 				 * top level shell.  Kind of strange since
576 				 * interactive is set if we are reading from
577 				 * a tty, but to have stopped jobs, one only
578 				 * needs FMONITOR set (not FTALKING/SF_TTY)...
579 				 */
580 				/* toss any input we have so far */
581 				s->start = s->str = null;
582 				break;
583 			}
584 			/* FALLTHROUGH */
585 		case LEXIT:
586 		case LLEAVE:
587 		case LRETURN:
588 			source = old_source;
589 			quitenv(NULL);
590 			unwind(i);	/* keep on going */
591 			/* NOTREACHED */
592 		default:
593 			source = old_source;
594 			quitenv(NULL);
595 			internal_errorf(1, "shell: %d", i);
596 			/* NOTREACHED */
597 		}
598 	}
599 
600 	while (1) {
601 		if (trap)
602 			runtraps(0);
603 
604 		if (s->next == NULL) {
605 			if (Flag(FVERBOSE))
606 				s->flags |= SF_ECHO;
607 			else
608 				s->flags &= ~SF_ECHO;
609 		}
610 
611 		if (interactive) {
612 			got_sigwinch = 1;
613 			j_notify();
614 			mcheck();
615 			set_prompt(PS1, s);
616 		}
617 
618 		t = compile(s);
619 		if (t != NULL && t->type == TEOF) {
620 			if (wastty && Flag(FIGNOREEOF) && --attempts > 0) {
621 				shellf("Use `exit' to leave ksh\n");
622 				s->type = SSTDIN;
623 			} else if (wastty && !really_exit &&
624 			    j_stopped_running()) {
625 				really_exit = 1;
626 				s->type = SSTDIN;
627 			} else {
628 				/* this for POSIX, which says EXIT traps
629 				 * shall be taken in the environment
630 				 * immediately after the last command
631 				 * executed.
632 				 */
633 				if (toplevel)
634 					unwind(LEXIT);
635 				break;
636 			}
637 		}
638 
639 		if (t && (!Flag(FNOEXEC) || (s->flags & SF_TTY)))
640 			exstat = execute(t, 0, NULL);
641 
642 		if (t != NULL && t->type != TEOF && interactive && really_exit)
643 			really_exit = 0;
644 
645 		reclaim();
646 	}
647 	quitenv(NULL);
648 	source = old_source;
649 	return exstat;
650 }
651 
652 /* return to closest error handler or shell(), exit if none found */
653 void
654 unwind(int i)
655 {
656 	/* ordering for EXIT vs ERR is a bit odd (this is what at&t ksh does) */
657 	if (i == LEXIT || (Flag(FERREXIT) && (i == LERROR || i == LINTR) &&
658 	    sigtraps[SIGEXIT_].trap)) {
659 		if (trap)
660 			runtraps(0);
661 		runtrap(&sigtraps[SIGEXIT_]);
662 		i = LLEAVE;
663 	} else if (Flag(FERREXIT) && (i == LERROR || i == LINTR)) {
664 		if (trap)
665 			runtraps(0);
666 		runtrap(&sigtraps[SIGERR_]);
667 		i = LLEAVE;
668 	}
669 	while (1) {
670 		switch (genv->type) {
671 		case E_PARSE:
672 		case E_FUNC:
673 		case E_INCL:
674 		case E_LOOP:
675 		case E_ERRH:
676 			siglongjmp(genv->jbuf, i);
677 			/* NOTREACHED */
678 
679 		case E_NONE:
680 			if (i == LINTR)
681 				genv->flags |= EF_FAKE_SIGDIE;
682 			/* FALLTHROUGH */
683 
684 		default:
685 			quitenv(NULL);
686 			/*
687 			 * quitenv() may have reclaimed the memory
688 			 * used by source which will end badly when
689 			 * we jump to a function that expects it to
690 			 * be valid
691 			 */
692 			source = NULL;
693 		}
694 	}
695 }
696 
697 void
698 newenv(int type)
699 {
700 	struct env *ep;
701 
702 	ep = alloc(sizeof(*ep), ATEMP);
703 	ep->type = type;
704 	ep->flags = 0;
705 	ainit(&ep->area);
706 	ep->loc = genv->loc;
707 	ep->savefd = NULL;
708 	ep->oenv = genv;
709 	ep->temps = NULL;
710 	genv = ep;
711 }
712 
713 void
714 quitenv(struct shf *shf)
715 {
716 	struct env *ep = genv;
717 	int fd;
718 
719 	if (ep->oenv && ep->oenv->loc != ep->loc)
720 		popblock();
721 	if (ep->savefd != NULL) {
722 		for (fd = 0; fd < NUFILE; fd++)
723 			/* if ep->savefd[fd] < 0, means fd was closed */
724 			if (ep->savefd[fd])
725 				restfd(fd, ep->savefd[fd]);
726 		if (ep->savefd[2]) /* Clear any write errors */
727 			shf_reopen(2, SHF_WR, shl_out);
728 	}
729 
730 	/* Bottom of the stack.
731 	 * Either main shell is exiting or cleanup_parents_env() was called.
732 	 */
733 	if (ep->oenv == NULL) {
734 		if (ep->type == E_NONE) {	/* Main shell exiting? */
735 			if (Flag(FTALKING))
736 				hist_finish();
737 			j_exit();
738 			if (ep->flags & EF_FAKE_SIGDIE) {
739 				int sig = exstat - 128;
740 
741 				/* ham up our death a bit (at&t ksh
742 				 * only seems to do this for SIGTERM)
743 				 * Don't do it for SIGQUIT, since we'd
744 				 * dump a core..
745 				 */
746 				if ((sig == SIGINT || sig == SIGTERM) &&
747 				    getpgrp() == kshpid) {
748 					setsig(&sigtraps[sig], SIG_DFL,
749 					    SS_RESTORE_CURR|SS_FORCE);
750 					kill(0, sig);
751 				}
752 			}
753 		}
754 		if (shf)
755 			shf_close(shf);
756 		reclaim();
757 		exit(exstat);
758 	}
759 	if (shf)
760 		shf_close(shf);
761 	reclaim();
762 
763 	genv = genv->oenv;
764 	afree(ep, ATEMP);
765 }
766 
767 /* Called after a fork to cleanup stuff left over from parents environment */
768 void
769 cleanup_parents_env(void)
770 {
771 	struct env *ep;
772 	int fd;
773 
774 	/* Don't clean up temporary files - parent will probably need them.
775 	 * Also, can't easily reclaim memory since variables, etc. could be
776 	 * anywhere.
777 	 */
778 
779 	/* close all file descriptors hiding in savefd */
780 	for (ep = genv; ep; ep = ep->oenv) {
781 		if (ep->savefd) {
782 			for (fd = 0; fd < NUFILE; fd++)
783 				if (ep->savefd[fd] > 0)
784 					close(ep->savefd[fd]);
785 			afree(ep->savefd, &ep->area);
786 			ep->savefd = NULL;
787 		}
788 	}
789 	genv->oenv = NULL;
790 }
791 
792 /* Called just before an execve cleanup stuff temporary files */
793 void
794 cleanup_proc_env(void)
795 {
796 	struct env *ep;
797 
798 	for (ep = genv; ep; ep = ep->oenv)
799 		remove_temps(ep->temps);
800 }
801 
802 /* remove temp files and free ATEMP Area */
803 static void
804 reclaim(void)
805 {
806 	remove_temps(genv->temps);
807 	genv->temps = NULL;
808 	afreeall(&genv->area);
809 }
810 
811 static void
812 remove_temps(struct temp *tp)
813 {
814 
815 	for (; tp != NULL; tp = tp->next)
816 		if (tp->pid == procpid) {
817 			unlink(tp->name);
818 		}
819 }
820 
821 /* Returns true if name refers to a restricted shell */
822 static int
823 is_restricted(char *name)
824 {
825 	char *p;
826 
827 	if ((p = strrchr(name, '/')))
828 		name = p + 1;
829 	/* accepts rsh, rksh, rpdksh, pdrksh */
830 	if (strcmp(name, "rsh") && \
831 		strcmp(name, "rksh") && \
832 		strcmp(name, "rpdksh") && \
833 		strcmp(name, "pdrksh"))
834 		return(0);
835 	else
836 		return(1);
837 
838 }
839