1/*	$OpenBSD: main.c,v 1.52 2013/06/15 17:25:19 millert Exp $	*/
2/*	$OpenBSD: tty.c,v 1.9 2006/03/14 22:08:01 deraadt Exp $	*/
3/*	$OpenBSD: io.c,v 1.22 2006/03/17 16:30:13 millert Exp $	*/
4/*	$OpenBSD: table.c,v 1.15 2012/02/19 07:52:30 otto Exp $	*/
5
6/*-
7 * Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
8 *		 2011, 2012, 2013
9 *	Thorsten Glaser <tg@mirbsd.org>
10 *
11 * Provided that these terms and disclaimer and all copyright notices
12 * are retained or reproduced in an accompanying document, permission
13 * is granted to deal in this work without restriction, including un-
14 * limited rights to use, publicly perform, distribute, sell, modify,
15 * merge, give away, or sublicence.
16 *
17 * This work is provided "AS IS" and WITHOUT WARRANTY of any kind, to
18 * the utmost extent permitted by applicable law, neither express nor
19 * implied; without malicious intent or gross negligence. In no event
20 * may a licensor, author or contributor be held liable for indirect,
21 * direct, other damage, loss, or other issues arising in any way out
22 * of dealing in the work, even if advised of the possibility of such
23 * damage or existence of a defect, except proven that it results out
24 * of said person's immediate fault when using the work as intended.
25 */
26
27#define EXTERN
28#include "sh.h"
29
30#if HAVE_LANGINFO_CODESET
31#include <langinfo.h>
32#endif
33#if HAVE_SETLOCALE_CTYPE
34#include <locale.h>
35#endif
36
37__RCSID("$MirOS: src/bin/mksh/main.c,v 1.269 2013/07/25 18:07:46 tg Exp $");
38
39extern char **environ;
40
41#ifndef MKSHRC_PATH
42#define MKSHRC_PATH	"~/.mkshrc"
43#endif
44
45#ifndef MKSH_DEFAULT_TMPDIR
46#define MKSH_DEFAULT_TMPDIR	"/tmp"
47#endif
48
49static uint8_t isuc(const char *);
50static int main_init(int, const char *[], Source **, struct block **);
51uint32_t chvt_rndsetup(const void *, size_t);
52void chvt_reinit(void);
53static void reclaim(void);
54static void remove_temps(struct temp *);
55static mksh_uari_t rndsetup(void);
56#ifdef SIGWINCH
57static void x_sigwinch(int);
58#endif
59
60static const char initifs[] = "IFS= \t\n";
61
62static const char initsubs[] =
63    "${PS2=> } ${PS3=#? } ${PS4=+ } ${SECONDS=0} ${TMOUT=0} ${EPOCHREALTIME=}";
64
65static const char *initcoms[] = {
66	Ttypeset, "-r", initvsn, NULL,
67	Ttypeset, "-x", "HOME", "PATH", "RANDOM", "SHELL", NULL,
68	Ttypeset, "-i10", "COLUMNS", "LINES", "SECONDS", "TMOUT", NULL,
69	Talias,
70	"integer=typeset -i",
71	Tlocal_typeset,
72	/* not "alias -t --": hash -r needs to work */
73	"hash=alias -t",
74	"type=whence -v",
75#if !defined(ANDROID) && !defined(MKSH_UNEMPLOYED)
76	/* not in Android for political reasons */
77	/* not in ARGE mksh due to no job control */
78	"stop=kill -STOP",
79	"suspend=kill -STOP $$",
80#endif
81	"autoload=typeset -fu",
82	"functions=typeset -f",
83	"history=fc -l",
84	"nameref=typeset -n",
85	"nohup=nohup ",
86	Tr_fc_e_dash,
87	"source=PATH=$PATH:. command .",
88	"login=exec login",
89	NULL,
90	 /* this is what AT&T ksh seems to track, with the addition of emacs */
91	Talias, "-tU",
92	"cat", "cc", "chmod", "cp", "date", "ed", "emacs", "grep", "ls",
93	"make", "mv", "pr", "rm", "sed", "sh", "vi", "who", NULL,
94	NULL
95};
96
97static const char *restr_com[] = {
98	Ttypeset, "-r", "PATH", "ENV", "SHELL", NULL
99};
100
101static bool initio_done;
102
103/* top-level parsing and execution environment */
104static struct env env;
105struct env *e = &env;
106
107static mksh_uari_t
108rndsetup(void)
109{
110	register uint32_t h;
111	struct {
112		ALLOC_ITEM alloc_INT;
113		void *dataptr, *stkptr, *mallocptr;
114#if defined(__GLIBC__) && (__GLIBC__ >= 2)
115		sigjmp_buf jbuf;
116#endif
117		struct timeval tv;
118	} *bufptr;
119	char *cp;
120
121	cp = alloc(sizeof(*bufptr) - ALLOC_SIZE, APERM);
122#ifdef DEBUG
123	/* clear the allocated space, for valgrind */
124	memset(cp, 0, sizeof(*bufptr) - ALLOC_SIZE);
125#endif
126	/* undo what alloc() did to the malloc result address */
127	bufptr = (void *)(cp - ALLOC_SIZE);
128	/* PIE or something similar provides us with deltas here */
129	bufptr->dataptr = &rndsetupstate;
130	/* ASLR in at least Windows, Linux, some BSDs */
131	bufptr->stkptr = &bufptr;
132	/* randomised malloc in BSD (and possibly others) */
133	bufptr->mallocptr = bufptr;
134#if defined(__GLIBC__) && (__GLIBC__ >= 2)
135	/* glibc pointer guard */
136	sigsetjmp(bufptr->jbuf, 1);
137#endif
138	/* introduce variation (and yes, second arg MBZ for portability) */
139	mksh_TIME(bufptr->tv);
140
141	h = chvt_rndsetup(bufptr, sizeof(*bufptr));
142
143	afree(cp, APERM);
144	return ((mksh_uari_t)h);
145}
146
147uint32_t
148chvt_rndsetup(const void *bp, size_t sz)
149{
150	register uint32_t h;
151
152	NZATInit(h);
153	/* variation through pid, ppid, and the works */
154	NZATUpdateMem(h, &rndsetupstate, sizeof(rndsetupstate));
155	/* some variation, some possibly entropy, depending on OE */
156	NZATUpdateMem(h, bp, sz);
157	NZAATFinish(h);
158
159	return (h);
160}
161
162void
163chvt_reinit(void)
164{
165	kshpid = procpid = getpid();
166	ksheuid = geteuid();
167	kshpgrp = getpgrp();
168	kshppid = getppid();
169}
170
171static const char *empty_argv[] = {
172	"mksh", NULL
173};
174
175static uint8_t
176isuc(const char *cx) {
177	char *cp, *x;
178	uint8_t rv = 0;
179
180	if (!cx || !*cx)
181		return (0);
182
183	/* uppercase a string duplicate */
184	strdupx(x, cx, ATEMP);
185	cp = x;
186	while ((*cp = ksh_toupper(*cp)))
187		++cp;
188
189	/* check for UTF-8 */
190	if (strstr(x, "UTF-8") || strstr(x, "UTF8"))
191		rv = 1;
192
193	/* free copy and out */
194	afree(x, ATEMP);
195	return (rv);
196}
197
198static int
199main_init(int argc, const char *argv[], Source **sp, struct block **lp)
200{
201	int argi, i;
202	Source *s = NULL;
203	struct block *l;
204	unsigned char restricted, errexit, utf_flag;
205	char *cp;
206	const char *ccp, **wp;
207	struct tbl *vp;
208	struct stat s_stdin;
209#if !defined(_PATH_DEFPATH) && defined(_CS_PATH)
210	ssize_t k;
211#endif
212
213	/* do things like getpgrp() et al. */
214	chvt_reinit();
215
216	/* make sure argv[] is sane */
217	if (!*argv) {
218		argv = empty_argv;
219		argc = 1;
220	}
221	kshname = argv[0];
222
223	/* initialise permanent Area */
224	ainit(&aperm);
225
226	/* set up base environment */
227	env.type = E_NONE;
228	ainit(&env.area);
229	/* set up global l->vars and l->funs */
230	newblock();
231
232	/* Do this first so output routines (eg, errorf, shellf) can work */
233	initio();
234
235	/* determine the basename (without '-' or path) of the executable */
236	ccp = kshname;
237	goto begin_parse_kshname;
238	while ((i = ccp[argi++])) {
239		if (i == '/') {
240			ccp += argi;
241 begin_parse_kshname:
242			argi = 0;
243			if (*ccp == '-')
244				++ccp;
245		}
246	}
247	if (!*ccp)
248		ccp = empty_argv[0];
249
250	/* define built-in commands and see if we were called as one */
251	ktinit(APERM, &builtins,
252	    /* currently up to 51 builtins: 75% of 128 = 2^7 */
253	    7);
254	for (i = 0; mkshbuiltins[i].name != NULL; i++)
255		if (!strcmp(ccp, builtin(mkshbuiltins[i].name,
256		    mkshbuiltins[i].func)))
257			Flag(FAS_BUILTIN) = 1;
258
259	if (!Flag(FAS_BUILTIN)) {
260		/* check for -T option early */
261		argi = parse_args(argv, OF_FIRSTTIME, NULL);
262		if (argi < 0)
263			return (1);
264
265#if defined(MKSH_BINSHPOSIX) || defined(MKSH_BINSHREDUCED)
266		/* are we called as -sh or /bin/sh or so? */
267		if (!strcmp(ccp, "sh")) {
268			/* either also turns off braceexpand */
269#ifdef MKSH_BINSHPOSIX
270			/* enable better POSIX conformance */
271			change_flag(FPOSIX, OF_FIRSTTIME, true);
272#endif
273#ifdef MKSH_BINSHREDUCED
274			/* enable kludge/compat mode */
275			change_flag(FSH, OF_FIRSTTIME, true);
276#endif
277		}
278#endif
279	}
280
281	initvar();
282
283	initctypes();
284
285	inittraps();
286
287	coproc_init();
288
289	/* set up variable and command dictionaries */
290	ktinit(APERM, &taliases, 0);
291	ktinit(APERM, &aliases, 0);
292#ifndef MKSH_NOPWNAM
293	ktinit(APERM, &homedirs, 0);
294#endif
295
296	/* define shell keywords */
297	initkeywords();
298
299	init_histvec();
300
301	/* initialise tty size before importing environment */
302	change_winsz();
303
304#ifdef _PATH_DEFPATH
305	def_path = _PATH_DEFPATH;
306#else
307#ifdef _CS_PATH
308	if ((k = confstr(_CS_PATH, NULL, 0)) > 0 &&
309	    confstr(_CS_PATH, cp = alloc(k + 1, APERM), k + 1) == k + 1)
310		def_path = cp;
311	else
312#endif
313		/*
314		 * this is uniform across all OSes unless it
315		 * breaks somewhere; don't try to optimise,
316		 * e.g. add stuff for Interix or remove /usr
317		 * for HURD, because e.g. Debian GNU/HURD is
318		 * "keeping a regular /usr"; this is supposed
319		 * to be a sane 'basic' default PATH
320		 */
321		def_path = "/bin:/usr/bin:/sbin:/usr/sbin";
322#endif
323
324	/*
325	 * Set PATH to def_path (will set the path global variable).
326	 * (import of environment below will probably change this setting).
327	 */
328	vp = global("PATH");
329	/* setstr can't fail here */
330	setstr(vp, def_path, KSH_RETURN_ERROR);
331
332	/*
333	 * Turn on nohup by default for now - will change to off
334	 * by default once people are aware of its existence
335	 * (AT&T ksh does not have a nohup option - it always sends
336	 * the hup).
337	 */
338	Flag(FNOHUP) = 1;
339
340	/*
341	 * Turn on brace expansion by default. AT&T kshs that have
342	 * alternation always have it on.
343	 */
344	Flag(FBRACEEXPAND) = 1;
345
346	/*
347	 * Turn on "set -x" inheritance by default.
348	 */
349	Flag(FXTRACEREC) = 1;
350
351#ifndef MKSH_NO_CMDLINE_EDITING
352	/*
353	 * Set edit mode to emacs by default, may be overridden
354	 * by the environment or the user. Also, we want tab completion
355	 * on in vi by default.
356	 */
357	change_flag(FEMACS, OF_SPECIAL, true);
358#if !MKSH_S_NOVI
359	Flag(FVITABCOMPLETE) = 1;
360#endif
361#endif
362
363	/* import environment */
364	if (environ != NULL)
365		for (wp = (const char **)environ; *wp != NULL; wp++)
366			typeset(*wp, IMPORT | EXPORT, 0, 0, 0);
367
368	/* for security */
369	typeset(initifs, 0, 0, 0, 0);
370
371	/* assign default shell variable values */
372	substitute(initsubs, 0);
373
374	/* Figure out the current working directory and set $PWD */
375	vp = global("PWD");
376	cp = str_val(vp);
377	/* Try to use existing $PWD if it is valid */
378	set_current_wd((cp[0] == '/' && test_eval(NULL, TO_FILEQ, cp, ".",
379	    true)) ? cp : NULL);
380	if (current_wd[0])
381		simplify_path(current_wd);
382	/* Only set pwd if we know where we are or if it had a bogus value */
383	if (current_wd[0] || *cp)
384		/* setstr can't fail here */
385		setstr(vp, current_wd, KSH_RETURN_ERROR);
386
387	for (wp = initcoms; *wp != NULL; wp++) {
388		shcomexec(wp);
389		while (*wp != NULL)
390			wp++;
391	}
392	setint_n(global("OPTIND"), 1, 10);
393
394	kshuid = getuid();
395	kshgid = getgid();
396	kshegid = getegid();
397
398	safe_prompt = ksheuid ? "$ " : "# ";
399	vp = global("PS1");
400	/* Set PS1 if unset or we are root and prompt doesn't contain a # */
401	if (!(vp->flag & ISSET) ||
402	    (!ksheuid && !strchr(str_val(vp), '#')))
403		/* setstr can't fail here */
404		setstr(vp, safe_prompt, KSH_RETURN_ERROR);
405	setint_n((vp = global("BASHPID")), 0, 10);
406	vp->flag |= INT_U;
407	setint_n((vp = global("PGRP")), (mksh_uari_t)kshpgrp, 10);
408	vp->flag |= INT_U;
409	setint_n((vp = global("PPID")), (mksh_uari_t)kshppid, 10);
410	vp->flag |= INT_U;
411	setint_n((vp = global("USER_ID")), (mksh_uari_t)ksheuid, 10);
412	vp->flag |= INT_U;
413	setint_n((vp = global("KSHUID")), (mksh_uari_t)kshuid, 10);
414	vp->flag |= INT_U;
415	setint_n((vp = global("KSHEGID")), (mksh_uari_t)kshegid, 10);
416	vp->flag |= INT_U;
417	setint_n((vp = global("KSHGID")), (mksh_uari_t)kshgid, 10);
418	vp->flag |= INT_U;
419	setint_n((vp = global("RANDOM")), rndsetup(), 10);
420	vp->flag |= INT_U;
421	setint_n((vp_pipest = global("PIPESTATUS")), 0, 10);
422
423	/* Set this before parsing arguments */
424	Flag(FPRIVILEGED) = kshuid != ksheuid || kshgid != kshegid;
425
426	/* this to note if monitor is set on command line (see below) */
427#ifndef MKSH_UNEMPLOYED
428	Flag(FMONITOR) = 127;
429#endif
430	/* this to note if utf-8 mode is set on command line (see below) */
431	UTFMODE = 2;
432
433	if (!Flag(FAS_BUILTIN)) {
434		argi = parse_args(argv, OF_CMDLINE, NULL);
435		if (argi < 0)
436			return (1);
437	}
438
439#if defined(DEBUG) && !defined(MKSH_LEGACY_MODE)
440	/* test wraparound of arithmetic types */
441	{
442		volatile long xl;
443		volatile unsigned long xul;
444		volatile int xi;
445		volatile unsigned int xui;
446		volatile mksh_ari_t xa;
447		volatile mksh_uari_t xua, xua2;
448		volatile uint8_t xc;
449
450		xa = 2147483647;
451		xua = 2147483647;
452		++xa;
453		++xua;
454		xua2 = xa;
455		xl = xa;
456		xul = xua;
457		xa = 0;
458		xua = 0;
459		--xa;
460		--xua;
461		xi = xa;
462		xui = xua;
463		xa = -1;
464		xua = xa;
465		++xa;
466		++xua;
467		xc = 0;
468		--xc;
469		if ((xua2 != 2147483648UL) ||
470		    (xl != (-2147483647L-1)) || (xul != 2147483648UL) ||
471		    (xi != -1) || (xui != 4294967295U) ||
472		    (xa != 0) || (xua != 0) || (xc != 255))
473			errorf("integer wraparound test failed");
474	}
475#endif
476
477	/* process this later only, default to off (hysterical raisins) */
478	utf_flag = UTFMODE;
479	UTFMODE = 0;
480
481	if (Flag(FAS_BUILTIN)) {
482		/* auto-detect from environment variables, always */
483		utf_flag = 3;
484	} else if (Flag(FCOMMAND)) {
485		s = pushs(SSTRINGCMDLINE, ATEMP);
486		if (!(s->start = s->str = argv[argi++]))
487			errorf("%s %s", "-c", "requires an argument");
488#if !defined(MKSH_SMALL)
489		while (*s->str) {
490			if (*s->str != ' ' && ctype(*s->str, C_QUOTE))
491				break;
492			s->str++;
493		}
494		if (!*s->str)
495			s->flags |= SF_MAYEXEC;
496		s->str = s->start;
497#endif
498#ifdef MKSH_MIDNIGHTBSD01ASH_COMPAT
499		/* compatibility to MidnightBSD 0.1 /bin/sh (kludge) */
500		if (Flag(FSH) && argv[argi] && !strcmp(argv[argi], "--"))
501			++argi;
502#endif
503		if (argv[argi])
504			kshname = argv[argi++];
505	} else if (argi < argc && !Flag(FSTDIN)) {
506		s = pushs(SFILE, ATEMP);
507		s->file = argv[argi++];
508		s->u.shf = shf_open(s->file, O_RDONLY, 0,
509		    SHF_MAPHI | SHF_CLEXEC);
510		if (s->u.shf == NULL) {
511			shl_stdout_ok = false;
512			warningf(true, "%s: %s", s->file, cstrerror(errno));
513			/* mandated by SUSv4 */
514			exstat = 127;
515			unwind(LERROR);
516		}
517		kshname = s->file;
518	} else {
519		Flag(FSTDIN) = 1;
520		s = pushs(SSTDIN, ATEMP);
521		s->file = "<stdin>";
522		s->u.shf = shf_fdopen(0, SHF_RD | can_seek(0),
523		    NULL);
524		if (isatty(0) && isatty(2)) {
525			Flag(FTALKING) = Flag(FTALKING_I) = 1;
526			/* The following only if isatty(0) */
527			s->flags |= SF_TTY;
528			s->u.shf->flags |= SHF_INTERRUPT;
529			s->file = NULL;
530		}
531	}
532
533	/* this bizarreness is mandated by POSIX */
534	if (fstat(0, &s_stdin) >= 0 && S_ISCHR(s_stdin.st_mode) &&
535	    Flag(FTALKING))
536		reset_nonblock(0);
537
538	/* initialise job control */
539	j_init();
540	/* do this after j_init() which calls tty_init_state() */
541	if (Flag(FTALKING)) {
542		if (utf_flag == 2) {
543#ifndef MKSH_ASSUME_UTF8
544			/* auto-detect from locale or environment */
545			utf_flag = 4;
546#elif MKSH_ASSUME_UTF8
547			utf_flag = 1;
548#else
549			/* always disable UTF-8 (for interactive) */
550			utf_flag = 0;
551#endif
552		}
553#ifndef MKSH_NO_CMDLINE_EDITING
554		x_init();
555#endif
556	}
557
558#ifdef SIGWINCH
559	sigtraps[SIGWINCH].flags |= TF_SHELL_USES;
560	setsig(&sigtraps[SIGWINCH], x_sigwinch,
561	    SS_RESTORE_ORIG|SS_FORCE|SS_SHTRAP);
562#endif
563
564	l = e->loc;
565	if (Flag(FAS_BUILTIN)) {
566		l->argc = argc;
567		l->argv = argv;
568		l->argv[0] = ccp;
569	} else {
570		l->argc = argc - argi;
571		/*
572		 * allocate a new array because otherwise, when we modify
573		 * it in-place, ps(1) output changes; the meaning of argc
574		 * here is slightly different as it excludes kshname, and
575		 * we add a trailing NULL sentinel as well
576		 */
577		l->argv = alloc2(l->argc + 2, sizeof(void *), APERM);
578		l->argv[0] = kshname;
579		memcpy(&l->argv[1], &argv[argi], l->argc * sizeof(void *));
580		l->argv[l->argc + 1] = NULL;
581		getopts_reset(1);
582	}
583
584	/* divine the initial state of the utf8-mode Flag */
585	ccp = null;
586	switch (utf_flag) {
587
588	/* auto-detect from locale or environment */
589	case 4:
590#if HAVE_SETLOCALE_CTYPE
591		ccp = setlocale(LC_CTYPE, "");
592#if HAVE_LANGINFO_CODESET
593		if (!isuc(ccp))
594			ccp = nl_langinfo(CODESET);
595#endif
596		if (!isuc(ccp))
597			ccp = null;
598		/* FALLTHROUGH */
599#endif
600
601	/* auto-detect from environment */
602	case 3:
603		/* these were imported from environ earlier */
604		if (ccp == null)
605			ccp = str_val(global("LC_ALL"));
606		if (ccp == null)
607			ccp = str_val(global("LC_CTYPE"));
608		if (ccp == null)
609			ccp = str_val(global("LANG"));
610		UTFMODE = isuc(ccp);
611		break;
612
613	/* not set on command line, not FTALKING */
614	case 2:
615	/* unknown values */
616	default:
617		utf_flag = 0;
618		/* FALLTHROUGH */
619
620	/* known values */
621	case 1:
622	case 0:
623		UTFMODE = utf_flag;
624		break;
625	}
626
627	/* Disable during .profile/ENV reading */
628	restricted = Flag(FRESTRICTED);
629	Flag(FRESTRICTED) = 0;
630	errexit = Flag(FERREXIT);
631	Flag(FERREXIT) = 0;
632
633	/*
634	 * Do this before profile/$ENV so that if it causes problems in them,
635	 * user will know why things broke.
636	 */
637	if (!current_wd[0] && Flag(FTALKING))
638		warningf(false, "can't determine current directory");
639
640	if (Flag(FLOGIN)) {
641		include(MKSH_SYSTEM_PROFILE, 0, NULL, true);
642		if (!Flag(FPRIVILEGED))
643			include(substitute("$HOME/.profile", 0), 0,
644			    NULL, true);
645	}
646	if (Flag(FPRIVILEGED))
647		include(MKSH_SUID_PROFILE, 0, NULL, true);
648	else if (Flag(FTALKING)) {
649		char *env_file;
650
651		/* include $ENV */
652		env_file = substitute(substitute("${ENV:-" MKSHRC_PATH "}", 0),
653		    DOTILDE);
654		if (*env_file != '\0')
655			include(env_file, 0, NULL, true);
656	}
657
658	if (restricted) {
659		shcomexec(restr_com);
660		/* After typeset command... */
661		Flag(FRESTRICTED) = 1;
662	}
663	Flag(FERREXIT) = errexit;
664
665	if (Flag(FTALKING) && s)
666		hist_init(s);
667	else
668		/* set after ENV */
669		Flag(FTRACKALL) = 1;
670
671	alarm_init();
672
673	*sp = s;
674	*lp = l;
675	return (0);
676}
677
678/* this indirection barrier reduces stack usage during normal operation */
679
680int
681main(int argc, const char *argv[])
682{
683	int rv;
684	Source *s;
685	struct block *l;
686
687	if ((rv = main_init(argc, argv, &s, &l)) == 0) {
688		if (Flag(FAS_BUILTIN)) {
689			rv = shcomexec(l->argv);
690		} else {
691			shell(s, true);
692			/* NOTREACHED */
693		}
694	}
695	return (rv);
696}
697
698int
699include(const char *name, int argc, const char **argv, bool intr_ok)
700{
701	Source *volatile s = NULL;
702	struct shf *shf;
703	const char **volatile old_argv;
704	volatile int old_argc;
705	int i;
706
707	shf = shf_open(name, O_RDONLY, 0, SHF_MAPHI | SHF_CLEXEC);
708	if (shf == NULL)
709		return (-1);
710
711	if (argv) {
712		old_argv = e->loc->argv;
713		old_argc = e->loc->argc;
714	} else {
715		old_argv = NULL;
716		old_argc = 0;
717	}
718	newenv(E_INCL);
719	if ((i = kshsetjmp(e->jbuf))) {
720		quitenv(s ? s->u.shf : NULL);
721		if (old_argv) {
722			e->loc->argv = old_argv;
723			e->loc->argc = old_argc;
724		}
725		switch (i) {
726		case LRETURN:
727		case LERROR:
728			/* see below */
729			return (exstat & 0xFF);
730		case LINTR:
731			/*
732			 * intr_ok is set if we are including .profile or $ENV.
733			 * If user ^Cs out, we don't want to kill the shell...
734			 */
735			if (intr_ok && ((exstat & 0xFF) - 128) != SIGTERM)
736				return (1);
737			/* FALLTHROUGH */
738		case LEXIT:
739		case LLEAVE:
740		case LSHELL:
741			unwind(i);
742			/* NOTREACHED */
743		default:
744			internal_errorf("%s %d", "include", i);
745			/* NOTREACHED */
746		}
747	}
748	if (argv) {
749		e->loc->argv = argv;
750		e->loc->argc = argc;
751	}
752	s = pushs(SFILE, ATEMP);
753	s->u.shf = shf;
754	strdupx(s->file, name, ATEMP);
755	i = shell(s, false);
756	quitenv(s->u.shf);
757	if (old_argv) {
758		e->loc->argv = old_argv;
759		e->loc->argc = old_argc;
760	}
761	/* & 0xff to ensure value not -1 */
762	return (i & 0xFF);
763}
764
765/* spawn a command into a shell optionally keeping track of the line number */
766int
767command(const char *comm, int line)
768{
769	Source *s;
770
771	s = pushs(SSTRING, ATEMP);
772	s->start = s->str = comm;
773	s->line = line;
774	return (shell(s, false));
775}
776
777/*
778 * run the commands from the input source, returning status.
779 */
780int
781shell(Source * volatile s, volatile bool toplevel)
782{
783	struct op *t;
784	volatile bool wastty = tobool(s->flags & SF_TTY);
785	volatile uint8_t attempts = 13;
786	volatile bool interactive = Flag(FTALKING) && toplevel;
787	volatile bool sfirst = true;
788	Source *volatile old_source = source;
789	int i;
790
791	newenv(E_PARSE);
792	if (interactive)
793		really_exit = false;
794	switch ((i = kshsetjmp(e->jbuf))) {
795	case 0:
796		break;
797	case LINTR:
798		/* we get here if SIGINT not caught or ignored */
799	case LERROR:
800	case LSHELL:
801		if (interactive) {
802			if (i == LINTR)
803				shellf("\n");
804			/*
805			 * Reset any eof that was read as part of a
806			 * multiline command.
807			 */
808			if (Flag(FIGNOREEOF) && s->type == SEOF && wastty)
809				s->type = SSTDIN;
810			/*
811			 * Used by exit command to get back to
812			 * top level shell. Kind of strange since
813			 * interactive is set if we are reading from
814			 * a tty, but to have stopped jobs, one only
815			 * needs FMONITOR set (not FTALKING/SF_TTY)...
816			 */
817			/* toss any input we have so far */
818			yyrecursive_pop(true);
819			s->start = s->str = null;
820			retrace_info = NULL;
821			herep = heres;
822			break;
823		}
824		/* FALLTHROUGH */
825	case LEXIT:
826	case LLEAVE:
827	case LRETURN:
828		source = old_source;
829		quitenv(NULL);
830		/* keep on going */
831		unwind(i);
832		/* NOTREACHED */
833	default:
834		source = old_source;
835		quitenv(NULL);
836		internal_errorf("%s %d", "shell", i);
837		/* NOTREACHED */
838	}
839	while (/* CONSTCOND */ 1) {
840		if (trap)
841			runtraps(0);
842
843		if (s->next == NULL) {
844			if (Flag(FVERBOSE))
845				s->flags |= SF_ECHO;
846			else
847				s->flags &= ~SF_ECHO;
848		}
849		if (interactive) {
850			j_notify();
851			set_prompt(PS1, s);
852		}
853		t = compile(s, sfirst);
854		sfirst = false;
855		if (!t)
856			goto source_no_tree;
857		if (t->type == TEOF) {
858			if (wastty && Flag(FIGNOREEOF) && --attempts > 0) {
859				shellf("Use 'exit' to leave mksh\n");
860				s->type = SSTDIN;
861			} else if (wastty && !really_exit &&
862			    j_stopped_running()) {
863				really_exit = true;
864				s->type = SSTDIN;
865			} else {
866				/*
867				 * this for POSIX which says EXIT traps
868				 * shall be taken in the environment
869				 * immediately after the last command
870				 * executed.
871				 */
872				if (toplevel)
873					unwind(LEXIT);
874				break;
875			}
876		}
877#if !defined(MKSH_SMALL)
878		  else if ((s->flags & SF_MAYEXEC) && t->type == TCOM)
879			t->u.evalflags |= DOTCOMEXEC;
880#endif
881		if (!Flag(FNOEXEC) || (s->flags & SF_TTY))
882			exstat = execute(t, 0, NULL) & 0xFF;
883
884		if (t->type != TEOF && interactive && really_exit)
885			really_exit = false;
886
887 source_no_tree:
888		reclaim();
889	}
890	quitenv(NULL);
891	source = old_source;
892	return (exstat & 0xFF);
893}
894
895/* return to closest error handler or shell(), exit if none found */
896/* note: i MUST NOT be 0 */
897void
898unwind(int i)
899{
900	/*
901	 * This is a kludge. We need to restore everything that was
902	 * changed in the new environment, see cid 1005090337C7A669439
903	 * and 10050903386452ACBF1, but fail to even save things most of
904	 * the time. funcs.c:c_eval() changes FERREXIT temporarily to 0,
905	 * which needs to be restored thus (related to Debian #696823).
906	 * We did not save the shell flags, so we use a special or'd
907	 * value here... this is mostly to clean up behind *other*
908	 * callers of unwind(LERROR) here; exec.c has the regular case.
909	 */
910	if (Flag(FERREXIT) & 0x80) {
911		/* GNU bash does not run this trapsig */
912		trapsig(ksh_SIGERR);
913		Flag(FERREXIT) &= ~0x80;
914	}
915
916	/* ordering for EXIT vs ERR is a bit odd (this is what AT&T ksh does) */
917	if (i == LEXIT || ((i == LERROR || i == LINTR) &&
918	    sigtraps[ksh_SIGEXIT].trap &&
919	    (!Flag(FTALKING) || Flag(FERREXIT)))) {
920		++trap_nested;
921		runtrap(&sigtraps[ksh_SIGEXIT], trap_nested == 1);
922		--trap_nested;
923		i = LLEAVE;
924	} else if (Flag(FERREXIT) == 1 && (i == LERROR || i == LINTR)) {
925		++trap_nested;
926		runtrap(&sigtraps[ksh_SIGERR], trap_nested == 1);
927		--trap_nested;
928		i = LLEAVE;
929	}
930
931	while (/* CONSTCOND */ 1) {
932		switch (e->type) {
933		case E_PARSE:
934		case E_FUNC:
935		case E_INCL:
936		case E_LOOP:
937		case E_ERRH:
938			kshlongjmp(e->jbuf, i);
939			/* NOTREACHED */
940		case E_NONE:
941			if (i == LINTR)
942				e->flags |= EF_FAKE_SIGDIE;
943			/* FALLTHROUGH */
944		default:
945			quitenv(NULL);
946		}
947	}
948}
949
950void
951newenv(int type)
952{
953	struct env *ep;
954	char *cp;
955
956	/*
957	 * struct env includes ALLOC_ITEM for alignment constraints
958	 * so first get the actually used memory, then assign it
959	 */
960	cp = alloc(sizeof(struct env) - ALLOC_SIZE, ATEMP);
961	/* undo what alloc() did to the malloc result address */
962	ep = (void *)(cp - ALLOC_SIZE);
963	/* initialise public members of struct env (not the ALLOC_ITEM) */
964	ainit(&ep->area);
965	ep->oenv = e;
966	ep->loc = e->loc;
967	ep->savefd = NULL;
968	ep->temps = NULL;
969	ep->yyrecursive_statep = NULL;
970	ep->type = type;
971	ep->flags = 0;
972	/* jump buffer is invalid because flags == 0 */
973	e = ep;
974}
975
976void
977quitenv(struct shf *shf)
978{
979	struct env *ep = e;
980	char *cp;
981	int fd;
982
983	yyrecursive_pop(true);
984	while (ep->oenv && ep->oenv->loc != ep->loc)
985		popblock();
986	if (ep->savefd != NULL) {
987		for (fd = 0; fd < NUFILE; fd++)
988			/* if ep->savefd[fd] < 0, means fd was closed */
989			if (ep->savefd[fd])
990				restfd(fd, ep->savefd[fd]);
991		if (ep->savefd[2])
992			/* Clear any write errors */
993			shf_reopen(2, SHF_WR, shl_out);
994	}
995	/*
996	 * Bottom of the stack.
997	 * Either main shell is exiting or cleanup_parents_env() was called.
998	 */
999	if (ep->oenv == NULL) {
1000#ifdef DEBUG_LEAKS
1001		int i;
1002#endif
1003
1004		if (ep->type == E_NONE) {
1005			/* Main shell exiting? */
1006#if HAVE_PERSISTENT_HISTORY
1007			if (Flag(FTALKING))
1008				hist_finish();
1009#endif
1010			j_exit();
1011			if (ep->flags & EF_FAKE_SIGDIE) {
1012				int sig = (exstat & 0xFF) - 128;
1013
1014				/*
1015				 * ham up our death a bit (AT&T ksh
1016				 * only seems to do this for SIGTERM)
1017				 * Don't do it for SIGQUIT, since we'd
1018				 * dump a core..
1019				 */
1020				if ((sig == SIGINT || sig == SIGTERM) &&
1021				    (kshpgrp == kshpid)) {
1022					setsig(&sigtraps[sig], SIG_DFL,
1023					    SS_RESTORE_CURR | SS_FORCE);
1024					kill(0, sig);
1025				}
1026			}
1027		}
1028		if (shf)
1029			shf_close(shf);
1030		reclaim();
1031#ifdef DEBUG_LEAKS
1032#ifndef MKSH_NO_CMDLINE_EDITING
1033		x_done();
1034#endif
1035#ifndef MKSH_NOPROSPECTOFWORK
1036		/* block at least SIGCHLD during/after afreeall */
1037		sigprocmask(SIG_BLOCK, &sm_sigchld, NULL);
1038#endif
1039		afreeall(APERM);
1040		for (fd = 3; fd < NUFILE; fd++)
1041			if ((i = fcntl(fd, F_GETFD, 0)) != -1 &&
1042			    (i & FD_CLOEXEC))
1043				close(fd);
1044		close(2);
1045		close(1);
1046		close(0);
1047#endif
1048		exit(exstat & 0xFF);
1049	}
1050	if (shf)
1051		shf_close(shf);
1052	reclaim();
1053
1054	e = e->oenv;
1055
1056	/* free the struct env - tricky due to the ALLOC_ITEM inside */
1057	cp = (void *)ep;
1058	afree(cp + ALLOC_SIZE, ATEMP);
1059}
1060
1061/* Called after a fork to cleanup stuff left over from parents environment */
1062void
1063cleanup_parents_env(void)
1064{
1065	struct env *ep;
1066	int fd;
1067
1068	mkssert(e != NULL);
1069
1070	/*
1071	 * Don't clean up temporary files - parent will probably need them.
1072	 * Also, can't easily reclaim memory since variables, etc. could be
1073	 * anywhere.
1074	 */
1075
1076	/* close all file descriptors hiding in savefd */
1077	for (ep = e; ep; ep = ep->oenv) {
1078		if (ep->savefd) {
1079			for (fd = 0; fd < NUFILE; fd++)
1080				if (ep->savefd[fd] > 0)
1081					close(ep->savefd[fd]);
1082			afree(ep->savefd, &ep->area);
1083			ep->savefd = NULL;
1084		}
1085#ifdef DEBUG_LEAKS
1086		if (ep->type != E_NONE)
1087			ep->type = E_GONE;
1088#endif
1089	}
1090#ifndef DEBUG_LEAKS
1091	e->oenv = NULL;
1092#endif
1093}
1094
1095/* Called just before an execve cleanup stuff temporary files */
1096void
1097cleanup_proc_env(void)
1098{
1099	struct env *ep;
1100
1101	for (ep = e; ep; ep = ep->oenv)
1102		remove_temps(ep->temps);
1103}
1104
1105/* remove temp files and free ATEMP Area */
1106static void
1107reclaim(void)
1108{
1109	struct block *l;
1110
1111	while ((l = e->loc) && (!e->oenv || e->oenv->loc != l)) {
1112		e->loc = l->next;
1113		afreeall(&l->area);
1114	}
1115
1116	remove_temps(e->temps);
1117	e->temps = NULL;
1118	afreeall(&e->area);
1119}
1120
1121static void
1122remove_temps(struct temp *tp)
1123{
1124	for (; tp != NULL; tp = tp->next)
1125		if (tp->pid == procpid)
1126			unlink(tp->tffn);
1127}
1128
1129/*
1130 * Initialise tty_fd. Used for tracking the size of the terminal,
1131 * saving/resetting tty modes upon forground job completion, and
1132 * for setting up the tty process group. Return values:
1133 *	0 = got controlling tty
1134 *	1 = got terminal but no controlling tty
1135 *	2 = cannot find a terminal
1136 *	3 = cannot dup fd
1137 *	4 = cannot make fd close-on-exec
1138 * An existing tty_fd is cached if no "better" one could be found,
1139 * i.e. if tty_devtty was already set or the new would not set it.
1140 */
1141int
1142tty_init_fd(void)
1143{
1144	int fd, rv, eno = 0;
1145	bool do_close = false, is_devtty = true;
1146
1147	if (tty_devtty) {
1148		/* already got a tty which is /dev/tty */
1149		return (0);
1150	}
1151
1152#ifdef _UWIN
1153	/*XXX imake style */
1154	if (isatty(3)) {
1155		/* fd 3 on UWIN _is_ /dev/tty (or our controlling tty) */
1156		fd = 3;
1157		goto got_fd;
1158	}
1159#endif
1160	if ((fd = open("/dev/tty", O_RDWR, 0)) >= 0) {
1161		do_close = true;
1162		goto got_fd;
1163	}
1164	eno = errno;
1165
1166	if (tty_fd >= 0) {
1167		/* already got a non-devtty one */
1168		rv = 1;
1169		goto out;
1170	}
1171	is_devtty = false;
1172
1173	if (isatty((fd = 0)) || isatty((fd = 2)))
1174		goto got_fd;
1175	/* cannot find one */
1176	rv = 2;
1177	/* assert: do_close == false */
1178	goto out;
1179
1180 got_fd:
1181	if ((rv = fcntl(fd, F_DUPFD, FDBASE)) < 0) {
1182		eno = errno;
1183		rv = 3;
1184		goto out;
1185	}
1186	if (fcntl(rv, F_SETFD, FD_CLOEXEC) < 0) {
1187		eno = errno;
1188		close(rv);
1189		rv = 4;
1190		goto out;
1191	}
1192	tty_fd = rv;
1193	tty_devtty = is_devtty;
1194	rv = eno = 0;
1195 out:
1196	if (do_close)
1197		close(fd);
1198	errno = eno;
1199	return (rv);
1200}
1201
1202/* A shell error occurred (eg, syntax error, etc.) */
1203
1204#define VWARNINGF_ERRORPREFIX	1
1205#define VWARNINGF_FILELINE	2
1206#define VWARNINGF_BUILTIN	4
1207#define VWARNINGF_INTERNAL	8
1208
1209static void vwarningf(unsigned int, const char *, va_list)
1210    MKSH_A_FORMAT(__printf__, 2, 0);
1211
1212static void
1213vwarningf(unsigned int flags, const char *fmt, va_list ap)
1214{
1215	if (fmt) {
1216		if (flags & VWARNINGF_INTERNAL)
1217			shf_fprintf(shl_out, "internal error: ");
1218		if (flags & VWARNINGF_ERRORPREFIX)
1219			error_prefix(tobool(flags & VWARNINGF_FILELINE));
1220		if ((flags & VWARNINGF_BUILTIN) &&
1221		    /* not set when main() calls parse_args() */
1222		    builtin_argv0 && builtin_argv0 != kshname)
1223			shf_fprintf(shl_out, "%s: ", builtin_argv0);
1224		shf_vfprintf(shl_out, fmt, ap);
1225		shf_putchar('\n', shl_out);
1226	}
1227	shf_flush(shl_out);
1228}
1229
1230void
1231errorfx(int rc, const char *fmt, ...)
1232{
1233	va_list va;
1234
1235	exstat = rc;
1236
1237	/* debugging: note that stdout not valid */
1238	shl_stdout_ok = false;
1239
1240	va_start(va, fmt);
1241	vwarningf(VWARNINGF_ERRORPREFIX | VWARNINGF_FILELINE, fmt, va);
1242	va_end(va);
1243	unwind(LERROR);
1244}
1245
1246void
1247errorf(const char *fmt, ...)
1248{
1249	va_list va;
1250
1251	exstat = 1;
1252
1253	/* debugging: note that stdout not valid */
1254	shl_stdout_ok = false;
1255
1256	va_start(va, fmt);
1257	vwarningf(VWARNINGF_ERRORPREFIX | VWARNINGF_FILELINE, fmt, va);
1258	va_end(va);
1259	unwind(LERROR);
1260}
1261
1262/* like errorf(), but no unwind is done */
1263void
1264warningf(bool fileline, const char *fmt, ...)
1265{
1266	va_list va;
1267
1268	va_start(va, fmt);
1269	vwarningf(VWARNINGF_ERRORPREFIX | (fileline ? VWARNINGF_FILELINE : 0),
1270	    fmt, va);
1271	va_end(va);
1272}
1273
1274/*
1275 * Used by built-in utilities to prefix shell and utility name to message
1276 * (also unwinds environments for special builtins).
1277 */
1278void
1279bi_errorf(const char *fmt, ...)
1280{
1281	va_list va;
1282
1283	/* debugging: note that stdout not valid */
1284	shl_stdout_ok = false;
1285
1286	exstat = 1;
1287
1288	va_start(va, fmt);
1289	vwarningf(VWARNINGF_ERRORPREFIX | VWARNINGF_FILELINE |
1290	    VWARNINGF_BUILTIN, fmt, va);
1291	va_end(va);
1292
1293	/*
1294	 * POSIX special builtins and ksh special builtins cause
1295	 * non-interactive shells to exit.
1296	 * XXX odd use of KEEPASN; also may not want LERROR here
1297	 */
1298	if (builtin_flag & SPEC_BI) {
1299		builtin_argv0 = NULL;
1300		unwind(LERROR);
1301	}
1302}
1303
1304/* Called when something that shouldn't happen does */
1305void
1306internal_errorf(const char *fmt, ...)
1307{
1308	va_list va;
1309
1310	va_start(va, fmt);
1311	vwarningf(VWARNINGF_INTERNAL, fmt, va);
1312	va_end(va);
1313	unwind(LERROR);
1314}
1315
1316void
1317internal_warningf(const char *fmt, ...)
1318{
1319	va_list va;
1320
1321	va_start(va, fmt);
1322	vwarningf(VWARNINGF_INTERNAL, fmt, va);
1323	va_end(va);
1324}
1325
1326/* used by error reporting functions to print "ksh: .kshrc[25]: " */
1327void
1328error_prefix(bool fileline)
1329{
1330	/* Avoid foo: foo[2]: ... */
1331	if (!fileline || !source || !source->file ||
1332	    strcmp(source->file, kshname) != 0)
1333		shf_fprintf(shl_out, "%s: ", kshname + (*kshname == '-'));
1334	if (fileline && source && source->file != NULL) {
1335		shf_fprintf(shl_out, "%s[%d]: ", source->file,
1336		    source->errline > 0 ? source->errline : source->line);
1337		source->errline = 0;
1338	}
1339}
1340
1341/* printf to shl_out (stderr) with flush */
1342void
1343shellf(const char *fmt, ...)
1344{
1345	va_list va;
1346
1347	if (!initio_done)
1348		/* shl_out may not be set up yet... */
1349		return;
1350	va_start(va, fmt);
1351	shf_vfprintf(shl_out, fmt, va);
1352	va_end(va);
1353	shf_flush(shl_out);
1354}
1355
1356/* printf to shl_stdout (stdout) */
1357void
1358shprintf(const char *fmt, ...)
1359{
1360	va_list va;
1361
1362	if (!shl_stdout_ok)
1363		internal_errorf("shl_stdout not valid");
1364	va_start(va, fmt);
1365	shf_vfprintf(shl_stdout, fmt, va);
1366	va_end(va);
1367}
1368
1369/* test if we can seek backwards fd (returns 0 or SHF_UNBUF) */
1370int
1371can_seek(int fd)
1372{
1373	struct stat statb;
1374
1375	return (fstat(fd, &statb) == 0 && !S_ISREG(statb.st_mode) ?
1376	    SHF_UNBUF : 0);
1377}
1378
1379#ifdef DF
1380int shl_dbg_fd;
1381#define NSHF_IOB 4
1382#else
1383#define NSHF_IOB 3
1384#endif
1385struct shf shf_iob[NSHF_IOB];
1386
1387void
1388initio(void)
1389{
1390#ifdef DF
1391	const char *lfp;
1392#endif
1393
1394	/* force buffer allocation */
1395	shf_fdopen(1, SHF_WR, shl_stdout);
1396	shf_fdopen(2, SHF_WR, shl_out);
1397	shf_fdopen(2, SHF_WR, shl_xtrace);
1398#ifdef DF
1399	if ((lfp = getenv("SDMKSH_PATH")) == NULL) {
1400		if ((lfp = getenv("HOME")) == NULL || *lfp != '/')
1401			errorf("cannot get home directory");
1402		lfp = shf_smprintf("%s/mksh-dbg.txt", lfp);
1403	}
1404
1405	if ((shl_dbg_fd = open(lfp, O_WRONLY | O_APPEND | O_CREAT, 0600)) < 0)
1406		errorf("cannot open debug output file %s", lfp);
1407	if (shl_dbg_fd < FDBASE) {
1408		int nfd;
1409
1410		nfd = fcntl(shl_dbg_fd, F_DUPFD, FDBASE);
1411		close(shl_dbg_fd);
1412		if ((shl_dbg_fd = nfd) == -1)
1413			errorf("cannot dup debug output file");
1414	}
1415	fcntl(shl_dbg_fd, F_SETFD, FD_CLOEXEC);
1416	shf_fdopen(shl_dbg_fd, SHF_WR, shl_dbg);
1417	DF("=== open ===");
1418#endif
1419	initio_done = true;
1420}
1421
1422/* A dup2() with error checking */
1423int
1424ksh_dup2(int ofd, int nfd, bool errok)
1425{
1426	int rv;
1427
1428	if (((rv = dup2(ofd, nfd)) < 0) && !errok && (errno != EBADF))
1429		errorf("too many files open in shell");
1430
1431#ifdef __ultrix
1432	/*XXX imake style */
1433	if (rv >= 0)
1434		fcntl(nfd, F_SETFD, 0);
1435#endif
1436
1437	return (rv);
1438}
1439
1440/*
1441 * Move fd from user space (0 <= fd < 10) to shell space (fd >= 10),
1442 * set close-on-exec flag. See FDBASE in sh.h, maybe 24 not 10 here.
1443 */
1444short
1445savefd(int fd)
1446{
1447	int nfd = fd;
1448
1449	if (fd < FDBASE && (nfd = fcntl(fd, F_DUPFD, FDBASE)) < 0 &&
1450	    errno == EBADF)
1451		return (-1);
1452	if (nfd < 0 || nfd > SHRT_MAX)
1453		errorf("too many files open in shell");
1454	fcntl(nfd, F_SETFD, FD_CLOEXEC);
1455	return ((short)nfd);
1456}
1457
1458void
1459restfd(int fd, int ofd)
1460{
1461	if (fd == 2)
1462		shf_flush(&shf_iob[/* fd */ 2]);
1463	if (ofd < 0)
1464		/* original fd closed */
1465		close(fd);
1466	else if (fd != ofd) {
1467		/*XXX: what to do if this dup fails? */
1468		ksh_dup2(ofd, fd, true);
1469		close(ofd);
1470	}
1471}
1472
1473void
1474openpipe(int *pv)
1475{
1476	int lpv[2];
1477
1478	if (pipe(lpv) < 0)
1479		errorf("can't create pipe - try again");
1480	pv[0] = savefd(lpv[0]);
1481	if (pv[0] != lpv[0])
1482		close(lpv[0]);
1483	pv[1] = savefd(lpv[1]);
1484	if (pv[1] != lpv[1])
1485		close(lpv[1]);
1486}
1487
1488void
1489closepipe(int *pv)
1490{
1491	close(pv[0]);
1492	close(pv[1]);
1493}
1494
1495/*
1496 * Called by iosetup() (deals with 2>&4, etc.), c_read, c_print to turn
1497 * a string (the X in 2>&X, read -uX, print -uX) into a file descriptor.
1498 */
1499int
1500check_fd(const char *name, int mode, const char **emsgp)
1501{
1502	int fd, fl;
1503
1504	if (name[0] == 'p' && !name[1])
1505		return (coproc_getfd(mode, emsgp));
1506	for (fd = 0; ksh_isdigit(*name); ++name)
1507		fd = (fd * 10) + *name - '0';
1508	if (*name || fd >= FDBASE) {
1509		if (emsgp)
1510			*emsgp = "illegal file descriptor name";
1511		return (-1);
1512	}
1513	if ((fl = fcntl(fd, F_GETFL, 0)) < 0) {
1514		if (emsgp)
1515			*emsgp = "bad file descriptor";
1516		return (-1);
1517	}
1518	fl &= O_ACCMODE;
1519	/*
1520	 * X_OK is a kludge to disable this check for dups (x<&1):
1521	 * historical shells never did this check (XXX don't know what
1522	 * POSIX has to say).
1523	 */
1524	if (!(mode & X_OK) && fl != O_RDWR && (
1525	    ((mode & R_OK) && fl != O_RDONLY) ||
1526	    ((mode & W_OK) && fl != O_WRONLY))) {
1527		if (emsgp)
1528			*emsgp = (fl == O_WRONLY) ?
1529			    "fd not open for reading" :
1530			    "fd not open for writing";
1531		return (-1);
1532	}
1533	return (fd);
1534}
1535
1536/* Called once from main */
1537void
1538coproc_init(void)
1539{
1540	coproc.read = coproc.readw = coproc.write = -1;
1541	coproc.njobs = 0;
1542	coproc.id = 0;
1543}
1544
1545/* Called by c_read() when eof is read - close fd if it is the co-process fd */
1546void
1547coproc_read_close(int fd)
1548{
1549	if (coproc.read >= 0 && fd == coproc.read) {
1550		coproc_readw_close(fd);
1551		close(coproc.read);
1552		coproc.read = -1;
1553	}
1554}
1555
1556/*
1557 * Called by c_read() and by iosetup() to close the other side of the
1558 * read pipe, so reads will actually terminate.
1559 */
1560void
1561coproc_readw_close(int fd)
1562{
1563	if (coproc.readw >= 0 && coproc.read >= 0 && fd == coproc.read) {
1564		close(coproc.readw);
1565		coproc.readw = -1;
1566	}
1567}
1568
1569/*
1570 * Called by c_print when a write to a fd fails with EPIPE and by iosetup
1571 * when co-process input is dup'd
1572 */
1573void
1574coproc_write_close(int fd)
1575{
1576	if (coproc.write >= 0 && fd == coproc.write) {
1577		close(coproc.write);
1578		coproc.write = -1;
1579	}
1580}
1581
1582/*
1583 * Called to check for existence of/value of the co-process file descriptor.
1584 * (Used by check_fd() and by c_read/c_print to deal with -p option).
1585 */
1586int
1587coproc_getfd(int mode, const char **emsgp)
1588{
1589	int fd = (mode & R_OK) ? coproc.read : coproc.write;
1590
1591	if (fd >= 0)
1592		return (fd);
1593	if (emsgp)
1594		*emsgp = "no coprocess";
1595	return (-1);
1596}
1597
1598/*
1599 * called to close file descriptors related to the coprocess (if any)
1600 * Should be called with SIGCHLD blocked.
1601 */
1602void
1603coproc_cleanup(int reuse)
1604{
1605	/* This to allow co-processes to share output pipe */
1606	if (!reuse || coproc.readw < 0 || coproc.read < 0) {
1607		if (coproc.read >= 0) {
1608			close(coproc.read);
1609			coproc.read = -1;
1610		}
1611		if (coproc.readw >= 0) {
1612			close(coproc.readw);
1613			coproc.readw = -1;
1614		}
1615	}
1616	if (coproc.write >= 0) {
1617		close(coproc.write);
1618		coproc.write = -1;
1619	}
1620}
1621
1622struct temp *
1623maketemp(Area *ap, Temp_type type, struct temp **tlist)
1624{
1625	char *cp;
1626	size_t len;
1627	int i, j;
1628	struct temp *tp;
1629	const char *dir;
1630	struct stat sb;
1631
1632	dir = tmpdir ? tmpdir : MKSH_DEFAULT_TMPDIR;
1633	/* add "/shXXXXXX.tmp" plus NUL */
1634	len = strlen(dir);
1635	checkoktoadd(len, offsetof(struct temp, tffn[0]) + 14);
1636	tp = alloc(offsetof(struct temp, tffn[0]) + 14 + len, ap);
1637
1638	tp->shf = NULL;
1639	tp->pid = procpid;
1640	tp->type = type;
1641
1642	if (stat(dir, &sb) || !S_ISDIR(sb.st_mode)) {
1643		tp->tffn[0] = '\0';
1644		goto maketemp_out;
1645	}
1646
1647	cp = (void *)tp;
1648	cp += offsetof(struct temp, tffn[0]);
1649	memcpy(cp, dir, len);
1650	cp += len;
1651	memcpy(cp, "/shXXXXXX.tmp", 14);
1652	/* point to the first of six Xes */
1653	cp += 3;
1654	/* generate random part of filename */
1655	len = -1;
1656	do {
1657		i = rndget() % 36;
1658		cp[++len] = i < 26 ? 'a' + i : '0' + i - 26;
1659	} while (len < 5);
1660
1661	/* cyclically attempt to open a temporary file */
1662	while ((i = open(tp->tffn, O_CREAT | O_EXCL | O_RDWR, 0600)) < 0) {
1663		if (errno != EEXIST)
1664			goto maketemp_out;
1665		/* count down from z to a then from 9 to 0 */
1666		while (cp[len] == '0')
1667			if (!len--)
1668				goto maketemp_out;
1669		if (cp[len] == 'a')
1670			cp[len] = '9';
1671		else
1672			--cp[len];
1673		/* do another cycle */
1674	}
1675
1676	if (type == TT_FUNSUB) {
1677		/* map us high and mark as close-on-exec */
1678		if ((j = savefd(i)) != i) {
1679			close(i);
1680			i = j;
1681		}
1682
1683		/* operation mode for the shf */
1684		j = SHF_RD;
1685	} else
1686		j = SHF_WR;
1687
1688	/* shf_fdopen cannot fail, so no fd leak */
1689	tp->shf = shf_fdopen(i, j, NULL);
1690
1691 maketemp_out:
1692	tp->next = *tlist;
1693	*tlist = tp;
1694	return (tp);
1695}
1696
1697/*
1698 * We use a similar collision resolution algorithm as Python 2.5.4
1699 * but with a slightly tweaked implementation written from scratch.
1700 */
1701
1702#define	INIT_TBLSHIFT	3	/* initial table shift (2^3 = 8) */
1703#define PERTURB_SHIFT	5	/* see Python 2.5.4 Objects/dictobject.c */
1704
1705static void tgrow(struct table *);
1706static int tnamecmp(const void *, const void *);
1707
1708static void
1709tgrow(struct table *tp)
1710{
1711	size_t i, j, osize, mask, perturb;
1712	struct tbl *tblp, **pp;
1713	struct tbl **ntblp, **otblp = tp->tbls;
1714
1715	if (tp->tshift > 29)
1716		internal_errorf("hash table size limit reached");
1717
1718	/* calculate old size, new shift and new size */
1719	osize = (size_t)1 << (tp->tshift++);
1720	i = osize << 1;
1721
1722	ntblp = alloc2(i, sizeof(struct tbl *), tp->areap);
1723	/* multiplication cannot overflow: alloc2 checked that */
1724	memset(ntblp, 0, i * sizeof(struct tbl *));
1725
1726	/* table can get very full when reaching its size limit */
1727	tp->nfree = (tp->tshift == 30) ? 0x3FFF0000UL :
1728	    /* but otherwise, only 75% */
1729	    ((i * 3) / 4);
1730	tp->tbls = ntblp;
1731	if (otblp == NULL)
1732		return;
1733
1734	mask = i - 1;
1735	for (i = 0; i < osize; i++)
1736		if ((tblp = otblp[i]) != NULL) {
1737			if ((tblp->flag & DEFINED)) {
1738				/* search for free hash table slot */
1739				j = perturb = tblp->ua.hval;
1740				goto find_first_empty_slot;
1741 find_next_empty_slot:
1742				j = (j << 2) + j + perturb + 1;
1743				perturb >>= PERTURB_SHIFT;
1744 find_first_empty_slot:
1745				pp = &ntblp[j & mask];
1746				if (*pp != NULL)
1747					goto find_next_empty_slot;
1748				/* found an empty hash table slot */
1749				*pp = tblp;
1750				tp->nfree--;
1751			} else if (!(tblp->flag & FINUSE)) {
1752				afree(tblp, tp->areap);
1753			}
1754		}
1755	afree(otblp, tp->areap);
1756}
1757
1758void
1759ktinit(Area *ap, struct table *tp, uint8_t initshift)
1760{
1761	tp->areap = ap;
1762	tp->tbls = NULL;
1763	tp->tshift = ((initshift > INIT_TBLSHIFT) ?
1764	    initshift : INIT_TBLSHIFT) - 1;
1765	tgrow(tp);
1766}
1767
1768/* table, name (key) to search for, hash(name), rv pointer to tbl ptr */
1769struct tbl *
1770ktscan(struct table *tp, const char *name, uint32_t h, struct tbl ***ppp)
1771{
1772	size_t j, perturb, mask;
1773	struct tbl **pp, *p;
1774
1775	mask = ((size_t)1 << (tp->tshift)) - 1;
1776	/* search for hash table slot matching name */
1777	j = perturb = h;
1778	goto find_first_slot;
1779 find_next_slot:
1780	j = (j << 2) + j + perturb + 1;
1781	perturb >>= PERTURB_SHIFT;
1782 find_first_slot:
1783	pp = &tp->tbls[j & mask];
1784	if ((p = *pp) != NULL && (p->ua.hval != h || !(p->flag & DEFINED) ||
1785	    strcmp(p->name, name)))
1786		goto find_next_slot;
1787	/* p == NULL if not found, correct found entry otherwise */
1788	if (ppp)
1789		*ppp = pp;
1790	return (p);
1791}
1792
1793/* table, name (key) to enter, hash(n) */
1794struct tbl *
1795ktenter(struct table *tp, const char *n, uint32_t h)
1796{
1797	struct tbl **pp, *p;
1798	size_t len;
1799
1800 Search:
1801	if ((p = ktscan(tp, n, h, &pp)))
1802		return (p);
1803
1804	if (tp->nfree == 0) {
1805		/* too full */
1806		tgrow(tp);
1807		goto Search;
1808	}
1809
1810	/* create new tbl entry */
1811	len = strlen(n);
1812	checkoktoadd(len, offsetof(struct tbl, name[0]) + 1);
1813	p = alloc(offsetof(struct tbl, name[0]) + ++len, tp->areap);
1814	p->flag = 0;
1815	p->type = 0;
1816	p->areap = tp->areap;
1817	p->ua.hval = h;
1818	p->u2.field = 0;
1819	p->u.array = NULL;
1820	memcpy(p->name, n, len);
1821
1822	/* enter in tp->tbls */
1823	tp->nfree--;
1824	*pp = p;
1825	return (p);
1826}
1827
1828void
1829ktwalk(struct tstate *ts, struct table *tp)
1830{
1831	ts->left = (size_t)1 << (tp->tshift);
1832	ts->next = tp->tbls;
1833}
1834
1835struct tbl *
1836ktnext(struct tstate *ts)
1837{
1838	while (--ts->left >= 0) {
1839		struct tbl *p = *ts->next++;
1840		if (p != NULL && (p->flag & DEFINED))
1841			return (p);
1842	}
1843	return (NULL);
1844}
1845
1846static int
1847tnamecmp(const void *p1, const void *p2)
1848{
1849	const struct tbl *a = *((const struct tbl * const *)p1);
1850	const struct tbl *b = *((const struct tbl * const *)p2);
1851
1852	return (strcmp(a->name, b->name));
1853}
1854
1855struct tbl **
1856ktsort(struct table *tp)
1857{
1858	size_t i;
1859	struct tbl **p, **sp, **dp;
1860
1861	/*
1862	 * since the table is never entirely full, no need to reserve
1863	 * additional space for the trailing NULL appended below
1864	 */
1865	i = (size_t)1 << (tp->tshift);
1866	p = alloc2(i, sizeof(struct tbl *), ATEMP);
1867	sp = tp->tbls;		/* source */
1868	dp = p;			/* dest */
1869	while (i--)
1870		if ((*dp = *sp++) != NULL && (((*dp)->flag & DEFINED) ||
1871		    ((*dp)->flag & ARRAY)))
1872			dp++;
1873	qsort(p, (i = dp - p), sizeof(struct tbl *), tnamecmp);
1874	p[i] = NULL;
1875	return (p);
1876}
1877
1878#ifdef SIGWINCH
1879static void
1880x_sigwinch(int sig MKSH_A_UNUSED)
1881{
1882	/* this runs inside interrupt context, with errno saved */
1883
1884	got_winch = 1;
1885}
1886#endif
1887
1888#ifdef DF
1889void
1890DF(const char *fmt, ...)
1891{
1892	va_list args;
1893	struct timeval tv;
1894	mirtime_mjd mjd;
1895
1896	mksh_lockfd(shl_dbg_fd);
1897	mksh_TIME(tv);
1898	timet2mjd(&mjd, tv.tv_sec);
1899	shf_fprintf(shl_dbg, "[%02u:%02u:%02u (%u) %u.%06u] ",
1900	    (unsigned)mjd.sec / 3600, ((unsigned)mjd.sec / 60) % 60,
1901	    (unsigned)mjd.sec % 60, (unsigned)getpid(),
1902	    (unsigned)tv.tv_sec, (unsigned)tv.tv_usec);
1903	va_start(args, fmt);
1904	shf_vfprintf(shl_dbg, fmt, args);
1905	va_end(args);
1906	shf_putc('\n', shl_dbg);
1907	shf_flush(shl_dbg);
1908	mksh_unlkfd(shl_dbg_fd);
1909}
1910#endif
1911
1912void
1913x_mkraw(int fd, mksh_ttyst *ocb, bool forread)
1914{
1915	mksh_ttyst cb;
1916
1917	if (ocb)
1918		mksh_tcget(fd, ocb);
1919	else
1920		ocb = &tty_state;
1921
1922	cb = *ocb;
1923	if (forread) {
1924		cb.c_lflag &= ~(ICANON) | ECHO;
1925	} else {
1926		cb.c_iflag &= ~(INLCR | ICRNL);
1927		cb.c_lflag &= ~(ISIG | ICANON | ECHO);
1928	}
1929#if defined(VLNEXT) && defined(_POSIX_VDISABLE)
1930	/* OSF/1 processes lnext when ~icanon */
1931	cb.c_cc[VLNEXT] = _POSIX_VDISABLE;
1932#endif
1933	/* SunOS 4.1.x & OSF/1 processes discard(flush) when ~icanon */
1934#if defined(VDISCARD) && defined(_POSIX_VDISABLE)
1935	cb.c_cc[VDISCARD] = _POSIX_VDISABLE;
1936#endif
1937	cb.c_cc[VTIME] = 0;
1938	cb.c_cc[VMIN] = 1;
1939
1940	mksh_tcset(fd, &cb);
1941}
1942