xref: /openbsd/bin/ksh/main.c (revision 08cf2055)
1 /*	$OpenBSD: main.c,v 1.100 2023/07/23 23:42:03 kn 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 int	disable_subst;
39 
40 Area	aperm;
41 
42 struct env	*genv;
43 
44 char	shell_flags[FNFLAGS];
45 
46 char	null[] = "";
47 
48 int shl_stdout_ok;
49 
50 unsigned int	ksh_tmout;
51 enum tmout_enum	ksh_tmout_state = TMOUT_EXECUTING;
52 
53 int	really_exit;
54 
55 int ifs0 = ' ';
56 
57 volatile sig_atomic_t	trap;
58 volatile sig_atomic_t	intrsig;
59 volatile sig_atomic_t	fatal_trap;
60 
61 Getopt	builtin_opt;
62 Getopt	user_opt;
63 
64 struct coproc	coproc;
65 sigset_t	sm_default, sm_sigchld;
66 
67 char	*builtin_argv0;
68 int	 builtin_flag;
69 
70 char	*current_wd;
71 int	 current_wd_size;
72 
73 int	x_cols = 80;
74 
75 /*
76  * shell initialization
77  */
78 
79 static const char initifs[] = "IFS= \t\n";
80 
81 static const char initsubs[] = "${PS2=> } ${PS3=#? } ${PS4=+ }";
82 
83 static const char *initcoms [] = {
84 #ifndef SMALL
85 	"typeset", "-r", "KSH_VERSION", NULL,
86 #endif /* SMALL */
87 	"typeset", "-x", "SHELL", "PATH", "HOME", "PWD", "OLDPWD", NULL,
88 	"typeset", "-ir", "PPID", NULL,
89 	"typeset", "-i", "OPTIND=1", NULL,
90 #ifndef SMALL
91 	"eval", "typeset -i RANDOM MAILCHECK=\"${MAILCHECK-600}\" SECONDS=\"${SECONDS-0}\" TMOUT=\"${TMOUT-0}\"", NULL,
92 #else
93 	"eval", "typeset -i RANDOM SECONDS=\"${SECONDS-0}\" TMOUT=\"${TMOUT-0}\"", NULL,
94 #endif /* SMALL */
95 	"alias",
96 	 /* Standard ksh aliases */
97 	  "hash=alias -t",	/* not "alias -t --": hash -r needs to work */
98 	  "stop=kill -STOP",
99 	  "autoload=typeset -fu",
100 	  "functions=typeset -f",
101 	  "history=fc -l",
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 #ifndef SMALL
120 #define version_param  (initcoms[2])
121 #endif /* SMALL */
122 
123 /* The shell uses its own variation on argv, to build variables like
124  * $0 and $@.
125  * Allocate a new array since modifying the original argv will modify
126  * ps output.
127  */
128 static char **
make_argv(int argc,char * argv[])129 make_argv(int argc, char *argv[])
130 {
131 	int i;
132 	char **nargv;
133 
134 	nargv = areallocarray(NULL, argc + 1, sizeof(char *), &aperm);
135 	nargv[0] = (char *) kshname;
136 	for (i = 1; i < argc; i++)
137 		nargv[i] = argv[i];
138 	nargv[i] = NULL;
139 
140 	return nargv;
141 }
142 
143 int
main(int argc,char * argv[])144 main(int argc, char *argv[])
145 {
146 	int i;
147 	int argi;
148 	Source *s;
149 	struct block *l;
150 	int restricted, errexit;
151 	char **wp;
152 	struct env env;
153 	pid_t ppid;
154 
155 	kshname = argv[0];
156 
157 	if (issetugid()) { /* could later drop privileges */
158 		if (pledge("stdio rpath wpath cpath fattr flock getpw proc "
159 		    "exec tty id", NULL) == -1) {
160 			perror("pledge");
161 			exit(1);
162 		}
163 	} else {
164 		if (pledge("stdio rpath wpath cpath fattr flock getpw proc "
165 		    "exec tty", NULL) == -1) {
166 			perror("pledge");
167 			exit(1);
168 		}
169 	}
170 
171 	ainit(&aperm);		/* initialize permanent Area */
172 
173 	/* set up base environment */
174 	memset(&env, 0, sizeof(env));
175 	env.type = E_NONE;
176 	ainit(&env.area);
177 	genv = &env;
178 	newblock();		/* set up global l->vars and l->funs */
179 
180 	/* Do this first so output routines (eg, errorf, shellf) can work */
181 	initio();
182 
183 	initvar();
184 
185 	initctypes();
186 
187 	inittraps();
188 
189 	coproc_init();
190 
191 	/* set up variable and command dictionaries */
192 	ktinit(&taliases, APERM, 0);
193 	ktinit(&aliases, APERM, 0);
194 	ktinit(&homedirs, APERM, 0);
195 
196 	/* define shell keywords */
197 	initkeywords();
198 
199 	/* define built-in commands */
200 	ktinit(&builtins, APERM, 64); /* must be 2^n (currently 40 builtins) */
201 	for (i = 0; shbuiltins[i].name != NULL; i++)
202 		builtin(shbuiltins[i].name, shbuiltins[i].func);
203 	for (i = 0; kshbuiltins[i].name != NULL; i++)
204 		builtin(kshbuiltins[i].name, kshbuiltins[i].func);
205 
206 	init_histvec();
207 
208 	def_path = _PATH_DEFPATH;
209 	{
210 		size_t len = confstr(_CS_PATH, NULL, 0);
211 		char *new;
212 
213 		if (len > 0) {
214 			confstr(_CS_PATH, new = alloc(len + 1, APERM), len + 1);
215 			def_path = new;
216 		}
217 	}
218 
219 	/* Set PATH to def_path (will set the path global variable).
220 	 * (import of environment below will probably change this setting).
221 	 */
222 	{
223 		struct tbl *vp = global("PATH");
224 		/* setstr can't fail here */
225 		setstr(vp, def_path, KSH_RETURN_ERROR);
226 	}
227 
228 
229 	/* Turn on nohup by default for now - will change to off
230 	 * by default once people are aware of its existence
231 	 * (at&t ksh does not have a nohup option - it always sends
232 	 * the hup).
233 	 */
234 	Flag(FNOHUP) = 1;
235 
236 	/* Turn on brace expansion by default.  At&t ksh's that have
237 	 * alternation always have it on.  BUT, posix doesn't have
238 	 * brace expansion, so set this before setting up FPOSIX
239 	 * (change_flag() clears FBRACEEXPAND when FPOSIX is set).
240 	 */
241 	Flag(FBRACEEXPAND) = 1;
242 
243 	/* set posix flag just before environment so that it will have
244 	 * exactly the same effect as the POSIXLY_CORRECT environment
245 	 * variable.  If this needs to be done sooner to ensure correct posix
246 	 * operation, an initial scan of the environment will also have
247 	 * done sooner.
248 	 */
249 #ifdef POSIXLY_CORRECT
250 	change_flag(FPOSIX, OF_SPECIAL, 1);
251 #endif /* POSIXLY_CORRECT */
252 
253 	/* Check to see if we're /bin/sh. */
254 	if (!strcmp(kshname, "sh") || !strcmp(kshname, "-sh") ||
255 	    (strlen(kshname) >= 3 &&
256 	    !strcmp(&kshname[strlen(kshname) - 3], "/sh"))) {
257 		Flag(FSH) = 1;
258 #ifndef SMALL
259 		version_param = "SH_VERSION";
260 #endif /* SMALL */
261 	}
262 
263 	/* Set edit mode to emacs by default, may be overridden
264 	 * by the environment or the user.  Also, we want tab completion
265 	 * on in vi by default. */
266 #if defined(EMACS)
267 	change_flag(FEMACS, OF_SPECIAL, 1);
268 #endif /* EMACS */
269 #if defined(VI)
270 	Flag(FVITABCOMPLETE) = 1;
271 #endif /* VI */
272 
273 	/* import environment */
274 	if (environ != NULL)
275 		for (wp = environ; *wp != NULL; wp++)
276 			typeset(*wp, IMPORT|EXPORT, 0, 0, 0);
277 
278 	kshpid = procpid = getpid();
279 	typeset(initifs, 0, 0, 0, 0);	/* for security */
280 
281 	/* assign default shell variable values */
282 	substitute(initsubs, 0);
283 
284 	/* Figure out the current working directory and set $PWD */
285 	{
286 		struct stat s_pwd, s_dot;
287 		struct tbl *pwd_v = global("PWD");
288 		char *pwd = str_val(pwd_v);
289 		char *pwdx = pwd;
290 
291 		/* Try to use existing $PWD if it is valid */
292 		if (pwd[0] != '/' ||
293 		    stat(pwd, &s_pwd) == -1 || stat(".", &s_dot) == -1 ||
294 		    s_pwd.st_dev != s_dot.st_dev ||
295 		    s_pwd.st_ino != s_dot.st_ino)
296 			pwdx = NULL;
297 		set_current_wd(pwdx);
298 		if (current_wd[0])
299 			simplify_path(current_wd);
300 		/* Only set pwd if we know where we are or if it had a
301 		 * bogus value
302 		 */
303 		if (current_wd[0] || pwd != null)
304 			/* setstr can't fail here */
305 			setstr(pwd_v, current_wd, KSH_RETURN_ERROR);
306 	}
307 	ppid = getppid();
308 	setint(global("PPID"), (int64_t) ppid);
309 #ifndef SMALL
310 	/* setstr can't fail here */
311 	setstr(global(version_param), ksh_version, KSH_RETURN_ERROR);
312 #endif /* SMALL */
313 
314 	/* execute initialization statements */
315 	for (wp = (char**) initcoms; *wp != NULL; wp++) {
316 		shcomexec(wp);
317 		for (; *wp != NULL; wp++)
318 			;
319 	}
320 
321 
322 	ksheuid = geteuid();
323 	init_username();
324 	safe_prompt = ksheuid ? "$ " : "# ";
325 	{
326 		struct tbl *vp = global("PS1");
327 
328 		/* Set PS1 if it isn't set */
329 		if (!(vp->flag & ISSET)) {
330 			/* setstr can't fail here */
331 			setstr(vp, "\\h\\$ ", KSH_RETURN_ERROR);
332 		}
333 	}
334 
335 	/* Set this before parsing arguments */
336 	Flag(FPRIVILEGED) = getuid() != ksheuid || getgid() != getegid();
337 
338 	/* this to note if monitor is set on command line (see below) */
339 	Flag(FMONITOR) = 127;
340 	argi = parse_args(argv, OF_CMDLINE, NULL);
341 	if (argi < 0)
342 		exit(1);
343 
344 	if (Flag(FCOMMAND)) {
345 		s = pushs(SSTRING, ATEMP);
346 		if (!(s->start = s->str = argv[argi++]))
347 			errorf("-c requires an argument");
348 		if (argv[argi])
349 			kshname = argv[argi++];
350 	} else if (argi < argc && !Flag(FSTDIN)) {
351 		s = pushs(SFILE, ATEMP);
352 		s->file = argv[argi++];
353 		s->u.shf = shf_open(s->file, O_RDONLY, 0, SHF_MAPHI|SHF_CLEXEC);
354 		if (s->u.shf == NULL) {
355 			exstat = 127; /* POSIX */
356 			errorf("%s: %s", s->file, strerror(errno));
357 		}
358 		kshname = s->file;
359 	} else {
360 		Flag(FSTDIN) = 1;
361 		s = pushs(SSTDIN, ATEMP);
362 		s->file = "<stdin>";
363 		s->u.shf = shf_fdopen(0, SHF_RD | can_seek(0), NULL);
364 		if (isatty(0) && isatty(2)) {
365 			Flag(FTALKING) = Flag(FTALKING_I) = 1;
366 			/* The following only if isatty(0) */
367 			s->flags |= SF_TTY;
368 			s->u.shf->flags |= SHF_INTERRUPT;
369 			s->file = NULL;
370 		}
371 	}
372 
373 	/* This bizarreness is mandated by POSIX */
374 	{
375 		struct stat s_stdin;
376 
377 		if (fstat(0, &s_stdin) >= 0 && S_ISCHR(s_stdin.st_mode) &&
378 		    Flag(FTALKING))
379 			reset_nonblock(0);
380 	}
381 
382 	/* initialize job control */
383 	i = Flag(FMONITOR) != 127;
384 	Flag(FMONITOR) = 0;
385 	j_init(i);
386 	/* Do this after j_init(), as tty_fd is not initialized 'til then */
387 	if (Flag(FTALKING))
388 		x_init();
389 
390 	l = genv->loc;
391 	l->argv = make_argv(argc - (argi - 1), &argv[argi - 1]);
392 	l->argc = argc - argi;
393 	getopts_reset(1);
394 
395 	/* Disable during .profile/ENV reading */
396 	restricted = Flag(FRESTRICTED);
397 	Flag(FRESTRICTED) = 0;
398 	errexit = Flag(FERREXIT);
399 	Flag(FERREXIT) = 0;
400 
401 	/* Do this before profile/$ENV so that if it causes problems in them,
402 	 * user will know why things broke.
403 	 */
404 	if (!current_wd[0] && Flag(FTALKING))
405 		warningf(false, "Cannot determine current working directory");
406 
407 	if (Flag(FLOGIN)) {
408 		include(KSH_SYSTEM_PROFILE, 0, NULL, 1);
409 		if (!Flag(FPRIVILEGED))
410 			include(substitute("$HOME/.profile", 0), 0, NULL, 1);
411 	}
412 
413 	if (Flag(FPRIVILEGED))
414 		include("/etc/suid_profile", 0, NULL, 1);
415 	else if (Flag(FTALKING)) {
416 		char *env_file;
417 
418 		/* include $ENV */
419 		env_file = str_val(global("ENV"));
420 
421 #ifdef DEFAULT_ENV
422 		/* If env isn't set, include default environment */
423 		if (env_file == null)
424 			env_file = DEFAULT_ENV;
425 #endif /* DEFAULT_ENV */
426 		env_file = substitute(env_file, DOTILDE);
427 		if (*env_file != '\0')
428 			include(env_file, 0, NULL, 1);
429 	}
430 
431 	if (is_restricted(argv[0]) || is_restricted(str_val(global("SHELL"))))
432 		restricted = 1;
433 	if (restricted) {
434 		static const char *const restr_com[] = {
435 			"typeset", "-r", "PATH",
436 			"ENV", "SHELL",
437 			NULL
438 		};
439 		shcomexec((char **) restr_com);
440 		/* After typeset command... */
441 		Flag(FRESTRICTED) = 1;
442 	}
443 	if (errexit)
444 		Flag(FERREXIT) = 1;
445 
446 	if (Flag(FTALKING)) {
447 		hist_init(s);
448 		alarm_init();
449 	} else
450 		Flag(FTRACKALL) = 1;	/* set after ENV */
451 
452 	shell(s, true);	/* doesn't return */
453 	return 0;
454 }
455 
456 static void
init_username(void)457 init_username(void)
458 {
459 	char *p;
460 	struct tbl *vp = global("USER");
461 
462 	if (vp->flag & ISSET)
463 		p = ksheuid == 0 ? "root" : str_val(vp);
464 	else
465 		p = getlogin();
466 
467 	strlcpy(username, p != NULL ? p : "?", sizeof username);
468 }
469 
470 int
include(const char * name,int argc,char ** argv,int intr_ok)471 include(const char *name, int argc, char **argv, int intr_ok)
472 {
473 	Source *volatile s = NULL;
474 	struct shf *shf;
475 	char **volatile old_argv;
476 	volatile int old_argc;
477 	int i;
478 
479 	shf = shf_open(name, O_RDONLY, 0, SHF_MAPHI|SHF_CLEXEC);
480 	if (shf == NULL)
481 		return -1;
482 
483 	if (argv) {
484 		old_argv = genv->loc->argv;
485 		old_argc = genv->loc->argc;
486 	} else {
487 		old_argv = NULL;
488 		old_argc = 0;
489 	}
490 	newenv(E_INCL);
491 	i = sigsetjmp(genv->jbuf, 0);
492 	if (i) {
493 		quitenv(s ? s->u.shf : NULL);
494 		if (old_argv) {
495 			genv->loc->argv = old_argv;
496 			genv->loc->argc = old_argc;
497 		}
498 		switch (i) {
499 		case LRETURN:
500 		case LERROR:
501 			return exstat & 0xff; /* see below */
502 		case LINTR:
503 			/* intr_ok is set if we are including .profile or $ENV.
504 			 * If user ^C's out, we don't want to kill the shell...
505 			 */
506 			if (intr_ok && (exstat - 128) != SIGTERM)
507 				return 1;
508 			/* FALLTHROUGH */
509 		case LEXIT:
510 		case LLEAVE:
511 		case LSHELL:
512 			unwind(i);
513 			/* NOTREACHED */
514 		default:
515 			internal_errorf("%s: %d", __func__, i);
516 			/* NOTREACHED */
517 		}
518 	}
519 	if (argv) {
520 		genv->loc->argv = argv;
521 		genv->loc->argc = argc;
522 	}
523 	s = pushs(SFILE, ATEMP);
524 	s->u.shf = shf;
525 	s->file = str_save(name, ATEMP);
526 	i = shell(s, false);
527 	quitenv(s->u.shf);
528 	if (old_argv) {
529 		genv->loc->argv = old_argv;
530 		genv->loc->argc = old_argc;
531 	}
532 	return i & 0xff;	/* & 0xff to ensure value not -1 */
533 }
534 
535 /*
536  * spawn a command into a shell optionally keeping track of line
537  * number.
538  */
539 int
command(const char * comm,int line)540 command(const char *comm, int line)
541 {
542 	Source *s;
543 
544 	s = pushs(SSTRING, ATEMP);
545 	s->start = s->str = comm;
546 	s->line = line;
547 	return shell(s, false);
548 }
549 
550 /*
551  * run the commands from the input source, returning status.
552  */
553 int
shell(Source * volatile s,volatile int toplevel)554 shell(Source *volatile s, volatile int toplevel)
555 {
556 	struct op *t;
557 	volatile int wastty = s->flags & SF_TTY;
558 	volatile int attempts = 13;
559 	volatile int interactive = Flag(FTALKING) && toplevel;
560 	Source *volatile old_source = source;
561 	int i;
562 
563 	newenv(E_PARSE);
564 	if (interactive)
565 		really_exit = 0;
566 	i = sigsetjmp(genv->jbuf, 0);
567 	if (i) {
568 		switch (i) {
569 		case LINTR: /* we get here if SIGINT not caught or ignored */
570 		case LERROR:
571 		case LSHELL:
572 			if (interactive) {
573 				c_fc_reset();
574 				if (i == LINTR)
575 					shellf("\n");
576 				/* Reset any eof that was read as part of a
577 				 * multiline command.
578 				 */
579 				if (Flag(FIGNOREEOF) && s->type == SEOF &&
580 				    wastty)
581 					s->type = SSTDIN;
582 				/* Used by exit command to get back to
583 				 * top level shell.  Kind of strange since
584 				 * interactive is set if we are reading from
585 				 * a tty, but to have stopped jobs, one only
586 				 * needs FMONITOR set (not FTALKING/SF_TTY)...
587 				 */
588 				/* toss any input we have so far */
589 				s->start = s->str = null;
590 				break;
591 			}
592 			/* FALLTHROUGH */
593 		case LEXIT:
594 		case LLEAVE:
595 		case LRETURN:
596 			source = old_source;
597 			quitenv(NULL);
598 			unwind(i);	/* keep on going */
599 			/* NOTREACHED */
600 		default:
601 			source = old_source;
602 			quitenv(NULL);
603 			internal_errorf("%s: %d", __func__, i);
604 			/* NOTREACHED */
605 		}
606 	}
607 
608 	while (1) {
609 		if (trap)
610 			runtraps(0);
611 
612 		if (s->next == NULL) {
613 			if (Flag(FVERBOSE))
614 				s->flags |= SF_ECHO;
615 			else
616 				s->flags &= ~SF_ECHO;
617 		}
618 
619 		if (interactive) {
620 			got_sigwinch = 1;
621 			j_notify();
622 #ifndef SMALL
623 			mcheck();
624 #endif /* SMALL */
625 			set_prompt(PS1);
626 		}
627 
628 		t = compile(s);
629 		if (t != NULL && t->type == TEOF) {
630 			if (wastty && Flag(FIGNOREEOF) && --attempts > 0) {
631 				shellf("Use `exit' to leave ksh\n");
632 				s->type = SSTDIN;
633 			} else if (wastty && !really_exit &&
634 			    j_stopped_running()) {
635 				really_exit = 1;
636 				s->type = SSTDIN;
637 			} else {
638 				/* this for POSIX, which says EXIT traps
639 				 * shall be taken in the environment
640 				 * immediately after the last command
641 				 * executed.
642 				 */
643 				if (toplevel)
644 					unwind(LEXIT);
645 				break;
646 			}
647 		}
648 
649 		if (t && (!Flag(FNOEXEC) || (s->flags & SF_TTY)))
650 			exstat = execute(t, 0, NULL);
651 
652 		if (t != NULL && t->type != TEOF && interactive && really_exit)
653 			really_exit = 0;
654 
655 		reclaim();
656 	}
657 	quitenv(NULL);
658 	source = old_source;
659 	return exstat;
660 }
661 
662 /* return to closest error handler or shell(), exit if none found */
663 void
unwind(int i)664 unwind(int i)
665 {
666 	/* ordering for EXIT vs ERR is a bit odd (this is what at&t ksh does) */
667 	if (i == LEXIT || (Flag(FERREXIT) && (i == LERROR || i == LINTR) &&
668 	    sigtraps[SIGEXIT_].trap)) {
669 		if (trap)
670 			runtraps(0);
671 		runtrap(&sigtraps[SIGEXIT_]);
672 		i = LLEAVE;
673 	} else if (Flag(FERREXIT) && (i == LERROR || i == LINTR)) {
674 		if (trap)
675 			runtraps(0);
676 		runtrap(&sigtraps[SIGERR_]);
677 		i = LLEAVE;
678 	}
679 	while (1) {
680 		switch (genv->type) {
681 		case E_PARSE:
682 		case E_FUNC:
683 		case E_INCL:
684 		case E_LOOP:
685 		case E_ERRH:
686 			siglongjmp(genv->jbuf, i);
687 			/* NOTREACHED */
688 
689 		case E_NONE:
690 			if (i == LINTR)
691 				genv->flags |= EF_FAKE_SIGDIE;
692 			/* FALLTHROUGH */
693 
694 		default:
695 			quitenv(NULL);
696 			/*
697 			 * quitenv() may have reclaimed the memory
698 			 * used by source which will end badly when
699 			 * we jump to a function that expects it to
700 			 * be valid
701 			 */
702 			source = NULL;
703 		}
704 	}
705 }
706 
707 void
newenv(int type)708 newenv(int type)
709 {
710 	struct env *ep;
711 
712 	ep = alloc(sizeof(*ep), ATEMP);
713 	ep->type = type;
714 	ep->flags = 0;
715 	ainit(&ep->area);
716 	ep->loc = genv->loc;
717 	ep->savefd = NULL;
718 	ep->oenv = genv;
719 	ep->temps = NULL;
720 	genv = ep;
721 }
722 
723 void
quitenv(struct shf * shf)724 quitenv(struct shf *shf)
725 {
726 	struct env *ep = genv;
727 	int fd;
728 
729 	if (ep->oenv && ep->oenv->loc != ep->loc)
730 		popblock();
731 	if (ep->savefd != NULL) {
732 		for (fd = 0; fd < NUFILE; fd++)
733 			/* if ep->savefd[fd] < 0, means fd was closed */
734 			if (ep->savefd[fd])
735 				restfd(fd, ep->savefd[fd]);
736 		if (ep->savefd[2]) /* Clear any write errors */
737 			shf_reopen(2, SHF_WR, shl_out);
738 	}
739 
740 	/* Bottom of the stack.
741 	 * Either main shell is exiting or cleanup_parents_env() was called.
742 	 */
743 	if (ep->oenv == NULL) {
744 		if (ep->type == E_NONE) {	/* Main shell exiting? */
745 			if (Flag(FTALKING))
746 				hist_finish();
747 			j_exit();
748 			if (ep->flags & EF_FAKE_SIGDIE) {
749 				int sig = exstat - 128;
750 
751 				/* ham up our death a bit (at&t ksh
752 				 * only seems to do this for SIGTERM)
753 				 * Don't do it for SIGQUIT, since we'd
754 				 * dump a core..
755 				 */
756 				if ((sig == SIGINT || sig == SIGTERM) &&
757 				    getpgrp() == kshpid) {
758 					setsig(&sigtraps[sig], SIG_DFL,
759 					    SS_RESTORE_CURR|SS_FORCE);
760 					kill(0, sig);
761 				}
762 			}
763 		}
764 		if (shf)
765 			shf_close(shf);
766 		reclaim();
767 		exit(exstat);
768 	}
769 	if (shf)
770 		shf_close(shf);
771 	reclaim();
772 
773 	genv = genv->oenv;
774 	afree(ep, ATEMP);
775 }
776 
777 /* Called after a fork to cleanup stuff left over from parents environment */
778 void
cleanup_parents_env(void)779 cleanup_parents_env(void)
780 {
781 	struct env *ep;
782 	int fd;
783 
784 	/* Don't clean up temporary files - parent will probably need them.
785 	 * Also, can't easily reclaim memory since variables, etc. could be
786 	 * anywhere.
787 	 */
788 
789 	/* close all file descriptors hiding in savefd */
790 	for (ep = genv; ep; ep = ep->oenv) {
791 		if (ep->savefd) {
792 			for (fd = 0; fd < NUFILE; fd++)
793 				if (ep->savefd[fd] > 0)
794 					close(ep->savefd[fd]);
795 			afree(ep->savefd, &ep->area);
796 			ep->savefd = NULL;
797 		}
798 	}
799 	genv->oenv = NULL;
800 }
801 
802 /* Called just before an execve cleanup stuff temporary files */
803 void
cleanup_proc_env(void)804 cleanup_proc_env(void)
805 {
806 	struct env *ep;
807 
808 	for (ep = genv; ep; ep = ep->oenv)
809 		remove_temps(ep->temps);
810 }
811 
812 /* remove temp files and free ATEMP Area */
813 static void
reclaim(void)814 reclaim(void)
815 {
816 	remove_temps(genv->temps);
817 	genv->temps = NULL;
818 	afreeall(&genv->area);
819 }
820 
821 static void
remove_temps(struct temp * tp)822 remove_temps(struct temp *tp)
823 {
824 
825 	for (; tp != NULL; tp = tp->next)
826 		if (tp->pid == procpid) {
827 			unlink(tp->name);
828 		}
829 }
830 
831 /* Returns true if name refers to a restricted shell */
832 static int
is_restricted(char * name)833 is_restricted(char *name)
834 {
835 	char *p;
836 
837 	if ((p = strrchr(name, '/')))
838 		name = p + 1;
839 	/* accepts rsh, rksh, rpdksh, pdrksh */
840 	if (strcmp(name, "rsh") && \
841 		strcmp(name, "rksh") && \
842 		strcmp(name, "rpdksh") && \
843 		strcmp(name, "pdrksh"))
844 		return(0);
845 	else
846 		return(1);
847 
848 }
849