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      1 /*	$OpenBSD: exec.c,v 1.50 2013/06/10 21:09:27 millert Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
      5  *		 2011, 2012, 2013, 2014
      6  *	Thorsten Glaser <tg (at) mirbsd.org>
      7  *
      8  * Provided that these terms and disclaimer and all copyright notices
      9  * are retained or reproduced in an accompanying document, permission
     10  * is granted to deal in this work without restriction, including un-
     11  * limited rights to use, publicly perform, distribute, sell, modify,
     12  * merge, give away, or sublicence.
     13  *
     14  * This work is provided "AS IS" and WITHOUT WARRANTY of any kind, to
     15  * the utmost extent permitted by applicable law, neither express nor
     16  * implied; without malicious intent or gross negligence. In no event
     17  * may a licensor, author or contributor be held liable for indirect,
     18  * direct, other damage, loss, or other issues arising in any way out
     19  * of dealing in the work, even if advised of the possibility of such
     20  * damage or existence of a defect, except proven that it results out
     21  * of said person's immediate fault when using the work as intended.
     22  */
     23 
     24 #include "sh.h"
     25 
     26 __RCSID("$MirOS: src/bin/mksh/exec.c,v 1.133 2014/10/03 17:32:11 tg Exp $");
     27 
     28 #ifndef MKSH_DEFAULT_EXECSHELL
     29 #define MKSH_DEFAULT_EXECSHELL	"/bin/sh"
     30 #endif
     31 
     32 static int comexec(struct op *, struct tbl * volatile, const char **,
     33     int volatile, volatile int *);
     34 static void scriptexec(struct op *, const char **) MKSH_A_NORETURN;
     35 static int call_builtin(struct tbl *, const char **, const char *);
     36 static int iosetup(struct ioword *, struct tbl *);
     37 static int herein(struct ioword *, char **);
     38 static const char *do_selectargs(const char **, bool);
     39 static Test_op dbteste_isa(Test_env *, Test_meta);
     40 static const char *dbteste_getopnd(Test_env *, Test_op, bool);
     41 static void dbteste_error(Test_env *, int, const char *);
     42 static int search_access(const char *, int);
     43 /* XXX: horrible kludge to fit within the framework */
     44 static char *plain_fmt_entry(char *, size_t, unsigned int, const void *);
     45 static char *select_fmt_entry(char *, size_t, unsigned int, const void *);
     46 
     47 /*
     48  * execute command tree
     49  */
     50 int
     51 execute(struct op * volatile t,
     52     /* if XEXEC don't fork */
     53     volatile int flags,
     54     volatile int * volatile xerrok)
     55 {
     56 	int i;
     57 	volatile int rv = 0, dummy = 0;
     58 	int pv[2];
     59 	const char ** volatile ap = NULL;
     60 	char ** volatile up;
     61 	const char *s, *ccp;
     62 	struct ioword **iowp;
     63 	struct tbl *tp = NULL;
     64 	char *cp;
     65 
     66 	if (t == NULL)
     67 		return (0);
     68 
     69 	/* Caller doesn't care if XERROK should propagate. */
     70 	if (xerrok == NULL)
     71 		xerrok = &dummy;
     72 
     73 	if ((flags&XFORK) && !(flags&XEXEC) && t->type != TPIPE)
     74 		/* run in sub-process */
     75 		return (exchild(t, flags & ~XTIME, xerrok, -1));
     76 
     77 	newenv(E_EXEC);
     78 	if (trap)
     79 		runtraps(0);
     80 
     81 	/* we want to run an executable, do some variance checks */
     82 	if (t->type == TCOM) {
     83 		/* check if this is 'var=<<EOF' */
     84 		if (
     85 		    /* we have zero arguments, i.e. no programme to run */
     86 		    t->args[0] == NULL &&
     87 		    /* we have exactly one variable assignment */
     88 		    t->vars[0] != NULL && t->vars[1] == NULL &&
     89 		    /* we have exactly one I/O redirection */
     90 		    t->ioact != NULL && t->ioact[0] != NULL &&
     91 		    t->ioact[1] == NULL &&
     92 		    /* of type "here document" (or "here string") */
     93 		    (t->ioact[0]->flag & IOTYPE) == IOHERE &&
     94 		    /* the variable assignment begins with a valid varname */
     95 		    (ccp = skip_wdvarname(t->vars[0], true)) != t->vars[0] &&
     96 		    /* and has no right-hand side (i.e. "varname=") */
     97 		    ccp[0] == CHAR && ccp[1] == '=' && ccp[2] == EOS &&
     98 		    /* plus we can have a here document content */
     99 		    herein(t->ioact[0], &cp) == 0 && cp && *cp) {
    100 			char *sp = cp, *dp;
    101 			size_t n = ccp - t->vars[0] + 2, z;
    102 
    103 			/* drop redirection (will be garbage collected) */
    104 			t->ioact = NULL;
    105 
    106 			/* set variable to its expanded value */
    107 			z = strlen(cp) + 1;
    108 			if (notoktomul(z, 2) || notoktoadd(z * 2, n))
    109 				internal_errorf(Toomem, (size_t)-1);
    110 			dp = alloc(z * 2 + n, ATEMP);
    111 			memcpy(dp, t->vars[0], n);
    112 			t->vars[0] = dp;
    113 			dp += n;
    114 			while (*sp) {
    115 				*dp++ = QCHAR;
    116 				*dp++ = *sp++;
    117 			}
    118 			*dp = EOS;
    119 			/* free the expanded value */
    120 			afree(cp, APERM);
    121 		}
    122 
    123 		/*
    124 		 * Clear subst_exstat before argument expansion. Used by
    125 		 * null commands (see comexec() and c_eval()) and by c_set().
    126 		 */
    127 		subst_exstat = 0;
    128 
    129 		/* for $LINENO */
    130 		current_lineno = t->lineno;
    131 
    132 		/*
    133 		 * POSIX says expand command words first, then redirections,
    134 		 * and assignments last..
    135 		 */
    136 		up = eval(t->args, t->u.evalflags | DOBLANK | DOGLOB | DOTILDE);
    137 		if (flags & XTIME)
    138 			/* Allow option parsing (bizarre, but POSIX) */
    139 			timex_hook(t, &up);
    140 		ap = (const char **)up;
    141 		if (ap[0])
    142 			tp = findcom(ap[0], FC_BI|FC_FUNC);
    143 	}
    144 	flags &= ~XTIME;
    145 
    146 	if (t->ioact != NULL || t->type == TPIPE || t->type == TCOPROC) {
    147 		e->savefd = alloc2(NUFILE, sizeof(short), ATEMP);
    148 		/* initialise to not redirected */
    149 		memset(e->savefd, 0, NUFILE * sizeof(short));
    150 	}
    151 
    152 	/* mark for replacement later (unless TPIPE) */
    153 	vp_pipest->flag |= INT_L;
    154 
    155 	/* do redirection, to be restored in quitenv() */
    156 	if (t->ioact != NULL)
    157 		for (iowp = t->ioact; *iowp != NULL; iowp++) {
    158 			if (iosetup(*iowp, tp) < 0) {
    159 				exstat = rv = 1;
    160 				/*
    161 				 * Redirection failures for special commands
    162 				 * cause (non-interactive) shell to exit.
    163 				 */
    164 				if (tp && tp->type == CSHELL &&
    165 				    (tp->flag & SPEC_BI))
    166 					errorfz();
    167 				/* Deal with FERREXIT, quitenv(), etc. */
    168 				goto Break;
    169 			}
    170 		}
    171 
    172 	switch (t->type) {
    173 	case TCOM:
    174 		rv = comexec(t, tp, (const char **)ap, flags, xerrok);
    175 		break;
    176 
    177 	case TPAREN:
    178 		rv = execute(t->left, flags | XFORK, xerrok);
    179 		break;
    180 
    181 	case TPIPE:
    182 		flags |= XFORK;
    183 		flags &= ~XEXEC;
    184 		e->savefd[0] = savefd(0);
    185 		e->savefd[1] = savefd(1);
    186 		while (t->type == TPIPE) {
    187 			openpipe(pv);
    188 			/* stdout of curr */
    189 			ksh_dup2(pv[1], 1, false);
    190 			/**
    191 			 * Let exchild() close pv[0] in child
    192 			 * (if this isn't done, commands like
    193 			 *	(: ; cat /etc/termcap) | sleep 1
    194 			 * will hang forever).
    195 			 */
    196 			exchild(t->left, flags | XPIPEO | XCCLOSE,
    197 			    NULL, pv[0]);
    198 			/* stdin of next */
    199 			ksh_dup2(pv[0], 0, false);
    200 			closepipe(pv);
    201 			flags |= XPIPEI;
    202 			t = t->right;
    203 		}
    204 		/* stdout of last */
    205 		restfd(1, e->savefd[1]);
    206 		/* no need to re-restore this */
    207 		e->savefd[1] = 0;
    208 		/* Let exchild() close 0 in parent, after fork, before wait */
    209 		i = exchild(t, flags | XPCLOSE | XPIPEST, xerrok, 0);
    210 		if (!(flags&XBGND) && !(flags&XXCOM))
    211 			rv = i;
    212 		break;
    213 
    214 	case TLIST:
    215 		while (t->type == TLIST) {
    216 			execute(t->left, flags & XERROK, NULL);
    217 			t = t->right;
    218 		}
    219 		rv = execute(t, flags & XERROK, xerrok);
    220 		break;
    221 
    222 	case TCOPROC: {
    223 #ifndef MKSH_NOPROSPECTOFWORK
    224 		sigset_t omask;
    225 
    226 		/*
    227 		 * Block sigchild as we are using things changed in the
    228 		 * signal handler
    229 		 */
    230 		sigprocmask(SIG_BLOCK, &sm_sigchld, &omask);
    231 		e->type = E_ERRH;
    232 		if ((i = kshsetjmp(e->jbuf))) {
    233 			sigprocmask(SIG_SETMASK, &omask, NULL);
    234 			quitenv(NULL);
    235 			unwind(i);
    236 			/* NOTREACHED */
    237 		}
    238 #endif
    239 		/* Already have a (live) co-process? */
    240 		if (coproc.job && coproc.write >= 0)
    241 			errorf("coprocess already exists");
    242 
    243 		/* Can we re-use the existing co-process pipe? */
    244 		coproc_cleanup(true);
    245 
    246 		/* do this before opening pipes, in case these fail */
    247 		e->savefd[0] = savefd(0);
    248 		e->savefd[1] = savefd(1);
    249 
    250 		openpipe(pv);
    251 		if (pv[0] != 0) {
    252 			ksh_dup2(pv[0], 0, false);
    253 			close(pv[0]);
    254 		}
    255 		coproc.write = pv[1];
    256 		coproc.job = NULL;
    257 
    258 		if (coproc.readw >= 0)
    259 			ksh_dup2(coproc.readw, 1, false);
    260 		else {
    261 			openpipe(pv);
    262 			coproc.read = pv[0];
    263 			ksh_dup2(pv[1], 1, false);
    264 			/* closed before first read */
    265 			coproc.readw = pv[1];
    266 			coproc.njobs = 0;
    267 			/* create new coprocess id */
    268 			++coproc.id;
    269 		}
    270 #ifndef MKSH_NOPROSPECTOFWORK
    271 		sigprocmask(SIG_SETMASK, &omask, NULL);
    272 		/* no more need for error handler */
    273 		e->type = E_EXEC;
    274 #endif
    275 
    276 		/*
    277 		 * exchild() closes coproc.* in child after fork,
    278 		 * will also increment coproc.njobs when the
    279 		 * job is actually created.
    280 		 */
    281 		flags &= ~XEXEC;
    282 		exchild(t->left, flags | XBGND | XFORK | XCOPROC | XCCLOSE,
    283 		    NULL, coproc.readw);
    284 		break;
    285 	}
    286 
    287 	case TASYNC:
    288 		/*
    289 		 * XXX non-optimal, I think - "(foo &)", forks for (),
    290 		 * forks again for async... parent should optimise
    291 		 * this to "foo &"...
    292 		 */
    293 		rv = execute(t->left, (flags&~XEXEC)|XBGND|XFORK, xerrok);
    294 		break;
    295 
    296 	case TOR:
    297 	case TAND:
    298 		rv = execute(t->left, XERROK, xerrok);
    299 		if ((rv == 0) == (t->type == TAND))
    300 			rv = execute(t->right, flags & XERROK, xerrok);
    301 		else {
    302 			flags |= XERROK;
    303 			if (xerrok)
    304 				*xerrok = 1;
    305 		}
    306 		break;
    307 
    308 	case TBANG:
    309 		rv = !execute(t->right, XERROK, xerrok);
    310 		flags |= XERROK;
    311 		if (xerrok)
    312 			*xerrok = 1;
    313 		break;
    314 
    315 	case TDBRACKET: {
    316 		Test_env te;
    317 
    318 		te.flags = TEF_DBRACKET;
    319 		te.pos.wp = t->args;
    320 		te.isa = dbteste_isa;
    321 		te.getopnd = dbteste_getopnd;
    322 		te.eval = test_eval;
    323 		te.error = dbteste_error;
    324 
    325 		rv = test_parse(&te);
    326 		break;
    327 	}
    328 
    329 	case TFOR:
    330 	case TSELECT: {
    331 		volatile bool is_first = true;
    332 
    333 		ap = (t->vars == NULL) ? e->loc->argv + 1 :
    334 		    (const char **)eval((const char **)t->vars,
    335 		    DOBLANK | DOGLOB | DOTILDE);
    336 		e->type = E_LOOP;
    337 		while ((i = kshsetjmp(e->jbuf))) {
    338 			if ((e->flags&EF_BRKCONT_PASS) ||
    339 			    (i != LBREAK && i != LCONTIN)) {
    340 				quitenv(NULL);
    341 				unwind(i);
    342 			} else if (i == LBREAK) {
    343 				rv = 0;
    344 				goto Break;
    345 			}
    346 		}
    347 		/* in case of a continue */
    348 		rv = 0;
    349 		if (t->type == TFOR) {
    350 			while (*ap != NULL) {
    351 				setstr(global(t->str), *ap++, KSH_UNWIND_ERROR);
    352 				rv = execute(t->left, flags & XERROK, xerrok);
    353 			}
    354 		} else {
    355 			/* TSELECT */
    356 			for (;;) {
    357 				if (!(ccp = do_selectargs(ap, is_first))) {
    358 					rv = 1;
    359 					break;
    360 				}
    361 				is_first = false;
    362 				setstr(global(t->str), ccp, KSH_UNWIND_ERROR);
    363 				execute(t->left, flags & XERROK, xerrok);
    364 			}
    365 		}
    366 		break;
    367 	}
    368 
    369 	case TWHILE:
    370 	case TUNTIL:
    371 		e->type = E_LOOP;
    372 		while ((i = kshsetjmp(e->jbuf))) {
    373 			if ((e->flags&EF_BRKCONT_PASS) ||
    374 			    (i != LBREAK && i != LCONTIN)) {
    375 				quitenv(NULL);
    376 				unwind(i);
    377 			} else if (i == LBREAK) {
    378 				rv = 0;
    379 				goto Break;
    380 			}
    381 		}
    382 		/* in case of a continue */
    383 		rv = 0;
    384 		while ((execute(t->left, XERROK, NULL) == 0) ==
    385 		    (t->type == TWHILE))
    386 			rv = execute(t->right, flags & XERROK, xerrok);
    387 		break;
    388 
    389 	case TIF:
    390 	case TELIF:
    391 		if (t->right == NULL)
    392 			/* should be error */
    393 			break;
    394 		rv = execute(t->left, XERROK, NULL) == 0 ?
    395 		    execute(t->right->left, flags & XERROK, xerrok) :
    396 		    execute(t->right->right, flags & XERROK, xerrok);
    397 		break;
    398 
    399 	case TCASE:
    400 		i = 0;
    401 		ccp = evalstr(t->str, DOTILDE);
    402 		for (t = t->left; t != NULL && t->type == TPAT; t = t->right) {
    403 			for (ap = (const char **)t->vars; *ap; ap++) {
    404 				if (i || ((s = evalstr(*ap, DOTILDE|DOPAT)) &&
    405 				    gmatchx(ccp, s, false))) {
    406 					rv = execute(t->left, flags & XERROK,
    407 					    xerrok);
    408 					i = 0;
    409 					switch (t->u.charflag) {
    410 					case '&':
    411 						i = 1;
    412 						/* FALLTHROUGH */
    413 					case '|':
    414 						goto TCASE_next;
    415 					}
    416 					goto TCASE_out;
    417 				}
    418 			}
    419 			i = 0;
    420  TCASE_next:
    421 			/* empty */;
    422 		}
    423  TCASE_out:
    424 		break;
    425 
    426 	case TBRACE:
    427 		rv = execute(t->left, flags & XERROK, xerrok);
    428 		break;
    429 
    430 	case TFUNCT:
    431 		rv = define(t->str, t);
    432 		break;
    433 
    434 	case TTIME:
    435 		/*
    436 		 * Clear XEXEC so nested execute() call doesn't exit
    437 		 * (allows "ls -l | time grep foo").
    438 		 */
    439 		rv = timex(t, flags & ~XEXEC, xerrok);
    440 		break;
    441 
    442 	case TEXEC:
    443 		/* an eval'd TCOM */
    444 		s = t->args[0];
    445 		up = makenv();
    446 		restoresigs();
    447 		cleanup_proc_env();
    448 		{
    449 			union mksh_ccphack cargs;
    450 
    451 			cargs.ro = t->args;
    452 			execve(t->str, cargs.rw, up);
    453 			rv = errno;
    454 		}
    455 		if (rv == ENOEXEC)
    456 			scriptexec(t, (const char **)up);
    457 		else
    458 			errorf("%s: %s", s, cstrerror(rv));
    459 	}
    460  Break:
    461 	exstat = rv & 0xFF;
    462 	if (vp_pipest->flag & INT_L) {
    463 		unset(vp_pipest, 1);
    464 		vp_pipest->flag = DEFINED | ISSET | INTEGER | RDONLY |
    465 		    ARRAY | INT_U | INT_L;
    466 		vp_pipest->val.i = rv;
    467 	}
    468 
    469 	/* restores IO */
    470 	quitenv(NULL);
    471 	if ((flags&XEXEC))
    472 		/* exit child */
    473 		unwind(LEXIT);
    474 	if (rv != 0 && !(flags & XERROK) &&
    475 	    (xerrok == NULL || !*xerrok)) {
    476 		if (Flag(FERREXIT) & 0x80) {
    477 			/* inside eval */
    478 			Flag(FERREXIT) = 0;
    479 		} else {
    480 			trapsig(ksh_SIGERR);
    481 			if (Flag(FERREXIT))
    482 				unwind(LERROR);
    483 		}
    484 	}
    485 	return (rv);
    486 }
    487 
    488 /*
    489  * execute simple command
    490  */
    491 
    492 static int
    493 comexec(struct op *t, struct tbl * volatile tp, const char **ap,
    494     volatile int flags, volatile int *xerrok)
    495 {
    496 	int i;
    497 	volatile int rv = 0;
    498 	const char *cp;
    499 	const char **lastp;
    500 	/* Must be static (XXX but why?) */
    501 	static struct op texec;
    502 	int type_flags;
    503 	bool keepasn_ok;
    504 	int fcflags = FC_BI|FC_FUNC|FC_PATH;
    505 	bool bourne_function_call = false;
    506 	struct block *l_expand, *l_assign;
    507 
    508 	/*
    509 	 * snag the last argument for $_ XXX not the same as AT&T ksh,
    510 	 * which only seems to set $_ after a newline (but not in
    511 	 * functions/dot scripts, but in interactive and script) -
    512 	 * perhaps save last arg here and set it in shell()?.
    513 	 */
    514 	if (Flag(FTALKING) && *(lastp = ap)) {
    515 		while (*++lastp)
    516 			;
    517 		/* setstr() can't fail here */
    518 		setstr(typeset("_", LOCAL, 0, INTEGER, 0), *--lastp,
    519 		    KSH_RETURN_ERROR);
    520 	}
    521 
    522 	/**
    523 	 * Deal with the shell builtins builtin, exec and command since
    524 	 * they can be followed by other commands. This must be done before
    525 	 * we know if we should create a local block which must be done
    526 	 * before we can do a path search (in case the assignments change
    527 	 * PATH).
    528 	 * Odd cases:
    529 	 *	FOO=bar exec >/dev/null		FOO is kept but not exported
    530 	 *	FOO=bar exec foobar		FOO is exported
    531 	 *	FOO=bar command exec >/dev/null	FOO is neither kept nor exported
    532 	 *	FOO=bar command			FOO is neither kept nor exported
    533 	 *	PATH=... foobar			use new PATH in foobar search
    534 	 */
    535 	keepasn_ok = true;
    536 	while (tp && tp->type == CSHELL) {
    537 		/* undo effects of command */
    538 		fcflags = FC_BI|FC_FUNC|FC_PATH;
    539 		if (tp->val.f == c_builtin) {
    540 			if ((cp = *++ap) == NULL ||
    541 			    (!strcmp(cp, "--") && (cp = *++ap) == NULL)) {
    542 				tp = NULL;
    543 				break;
    544 			}
    545 			if ((tp = findcom(cp, FC_BI)) == NULL)
    546 				errorf("%s: %s: %s", Tbuiltin, cp, "not a builtin");
    547 			continue;
    548 		} else if (tp->val.f == c_exec) {
    549 			if (ap[1] == NULL)
    550 				break;
    551 			ap++;
    552 			flags |= XEXEC;
    553 		} else if (tp->val.f == c_command) {
    554 			int optc, saw_p = 0;
    555 
    556 			/*
    557 			 * Ugly dealing with options in two places (here
    558 			 * and in c_command(), but such is life)
    559 			 */
    560 			ksh_getopt_reset(&builtin_opt, 0);
    561 			while ((optc = ksh_getopt(ap, &builtin_opt, ":p")) == 'p')
    562 				saw_p = 1;
    563 			if (optc != EOF)
    564 				/* command -vV or something */
    565 				break;
    566 			/* don't look for functions */
    567 			fcflags = FC_BI|FC_PATH;
    568 			if (saw_p) {
    569 				if (Flag(FRESTRICTED)) {
    570 					warningf(true, "%s: %s",
    571 					    "command -p", "restricted");
    572 					rv = 1;
    573 					goto Leave;
    574 				}
    575 				fcflags |= FC_DEFPATH;
    576 			}
    577 			ap += builtin_opt.optind;
    578 			/*
    579 			 * POSIX says special builtins lose their status
    580 			 * if accessed using command.
    581 			 */
    582 			keepasn_ok = false;
    583 			if (!ap[0]) {
    584 				/* ensure command with no args exits with 0 */
    585 				subst_exstat = 0;
    586 				break;
    587 			}
    588 #ifndef MKSH_NO_EXTERNAL_CAT
    589 		} else if (tp->val.f == c_cat) {
    590 			/*
    591 			 * if we have any flags, do not use the builtin
    592 			 * in theory, we could allow -u, but that would
    593 			 * mean to use ksh_getopt here and possibly ad-
    594 			 * ded complexity and more code and isn't worth
    595 			 * additional hassle (and the builtin must call
    596 			 * ksh_getopt already but can't come back here)
    597 			 */
    598 			if (ap[1] && ap[1][0] == '-' && ap[1][1] != '\0' &&
    599 			    /* argument, begins with -, is not - or -- */
    600 			    (ap[1][1] != '-' || ap[1][2] != '\0'))
    601 				/* don't look for builtins or functions */
    602 				fcflags = FC_PATH;
    603 			else
    604 				/* go on, use the builtin */
    605 				break;
    606 #endif
    607 		} else if (tp->val.f == c_trap) {
    608 			t->u.evalflags &= ~DOTCOMEXEC;
    609 			break;
    610 		} else
    611 			break;
    612 		tp = findcom(ap[0], fcflags & (FC_BI|FC_FUNC));
    613 	}
    614 	if (t->u.evalflags & DOTCOMEXEC)
    615 		flags |= XEXEC;
    616 	l_expand = e->loc;
    617 	if (keepasn_ok && (!ap[0] || (tp && (tp->flag & KEEPASN))))
    618 		type_flags = 0;
    619 	else {
    620 		/* create new variable/function block */
    621 		newblock();
    622 		/* ksh functions don't keep assignments, POSIX functions do. */
    623 		if (keepasn_ok && tp && tp->type == CFUNC &&
    624 		    !(tp->flag & FKSH)) {
    625 			bourne_function_call = true;
    626 			type_flags = EXPORT;
    627 		} else
    628 			type_flags = LOCAL|LOCAL_COPY|EXPORT;
    629 	}
    630 	l_assign = e->loc;
    631 	if (Flag(FEXPORT))
    632 		type_flags |= EXPORT;
    633 	if (Flag(FXTRACE))
    634 		change_xtrace(2, false);
    635 	for (i = 0; t->vars[i]; i++) {
    636 		/* do NOT lookup in the new var/fn block just created */
    637 		e->loc = l_expand;
    638 		cp = evalstr(t->vars[i], DOASNTILDE | DOASNFIELD);
    639 		e->loc = l_assign;
    640 		if (Flag(FXTRACE)) {
    641 			const char *ccp;
    642 
    643 			ccp = skip_varname(cp, true);
    644 			if (*ccp == '+')
    645 				++ccp;
    646 			if (*ccp == '=')
    647 				++ccp;
    648 			shf_write(cp, ccp - cp, shl_xtrace);
    649 			print_value_quoted(shl_xtrace, ccp);
    650 			shf_putc(' ', shl_xtrace);
    651 		}
    652 		/* but assign in there as usual */
    653 		typeset(cp, type_flags, 0, 0, 0);
    654 		if (bourne_function_call && !(type_flags & EXPORT))
    655 			typeset(cp, LOCAL | LOCAL_COPY | EXPORT, 0, 0, 0);
    656 	}
    657 
    658 	if (Flag(FXTRACE)) {
    659 		change_xtrace(2, false);
    660 		if (ap[rv = 0]) {
    661  xtrace_ap_loop:
    662 			print_value_quoted(shl_xtrace, ap[rv]);
    663 			if (ap[++rv]) {
    664 				shf_putc(' ', shl_xtrace);
    665 				goto xtrace_ap_loop;
    666 			}
    667 		}
    668 		change_xtrace(1, false);
    669 	}
    670 
    671 	if ((cp = *ap) == NULL) {
    672 		rv = subst_exstat;
    673 		goto Leave;
    674 	} else if (!tp) {
    675 		if (Flag(FRESTRICTED) && vstrchr(cp, '/')) {
    676 			warningf(true, "%s: %s", cp, "restricted");
    677 			rv = 1;
    678 			goto Leave;
    679 		}
    680 		tp = findcom(cp, fcflags);
    681 	}
    682 
    683 	switch (tp->type) {
    684 
    685 	/* shell built-in */
    686 	case CSHELL:
    687 		rv = call_builtin(tp, (const char **)ap, null);
    688 		if (!keepasn_ok && tp->val.f == c_shift) {
    689 			l_expand->argc = l_assign->argc;
    690 			l_expand->argv = l_assign->argv;
    691 		}
    692 		break;
    693 
    694 	/* function call */
    695 	case CFUNC: {
    696 		volatile unsigned char old_xflag;
    697 		volatile uint32_t old_inuse;
    698 		const char * volatile old_kshname;
    699 
    700 		if (!(tp->flag & ISSET)) {
    701 			struct tbl *ftp;
    702 
    703 			if (!tp->u.fpath) {
    704 				rv = (tp->u2.errnov == ENOENT) ? 127 : 126;
    705 				warningf(true, "%s: %s %s: %s", cp,
    706 				    "can't find", "function definition file",
    707 				    cstrerror(tp->u2.errnov));
    708 				break;
    709 			}
    710 			if (include(tp->u.fpath, 0, NULL, false) < 0) {
    711 				warningf(true, "%s: %s %s %s: %s", cp,
    712 				    "can't open", "function definition file",
    713 				    tp->u.fpath, cstrerror(errno));
    714 				rv = 127;
    715 				break;
    716 			}
    717 			if (!(ftp = findfunc(cp, hash(cp), false)) ||
    718 			    !(ftp->flag & ISSET)) {
    719 				warningf(true, "%s: %s %s", cp,
    720 				    "function not defined by", tp->u.fpath);
    721 				rv = 127;
    722 				break;
    723 			}
    724 			tp = ftp;
    725 		}
    726 
    727 		/*
    728 		 * ksh functions set $0 to function name, POSIX
    729 		 * functions leave $0 unchanged.
    730 		 */
    731 		old_kshname = kshname;
    732 		if (tp->flag & FKSH)
    733 			kshname = ap[0];
    734 		else
    735 			ap[0] = kshname;
    736 		e->loc->argv = ap;
    737 		for (i = 0; *ap++ != NULL; i++)
    738 			;
    739 		e->loc->argc = i - 1;
    740 		/*
    741 		 * ksh-style functions handle getopts sanely,
    742 		 * Bourne/POSIX functions are insane...
    743 		 */
    744 		if (tp->flag & FKSH) {
    745 			e->loc->flags |= BF_DOGETOPTS;
    746 			e->loc->getopts_state = user_opt;
    747 			getopts_reset(1);
    748 		}
    749 
    750 		old_xflag = Flag(FXTRACE) ? 1 : 0;
    751 		change_xtrace((Flag(FXTRACEREC) ? old_xflag : 0) |
    752 		    ((tp->flag & TRACE) ? 1 : 0), false);
    753 		old_inuse = tp->flag & FINUSE;
    754 		tp->flag |= FINUSE;
    755 
    756 		e->type = E_FUNC;
    757 		if (!(i = kshsetjmp(e->jbuf))) {
    758 			execute(tp->val.t, flags & XERROK, NULL);
    759 			i = LRETURN;
    760 		}
    761 
    762 		kshname = old_kshname;
    763 		change_xtrace(old_xflag, false);
    764 		tp->flag = (tp->flag & ~FINUSE) | old_inuse;
    765 
    766 		/*
    767 		 * Were we deleted while executing? If so, free the
    768 		 * execution tree. TODO: Unfortunately, the table entry
    769 		 * is never re-used until the lookup table is expanded.
    770 		 */
    771 		if ((tp->flag & (FDELETE|FINUSE)) == FDELETE) {
    772 			if (tp->flag & ALLOC) {
    773 				tp->flag &= ~ALLOC;
    774 				tfree(tp->val.t, tp->areap);
    775 			}
    776 			tp->flag = 0;
    777 		}
    778 		switch (i) {
    779 		case LRETURN:
    780 		case LERROR:
    781 			rv = exstat & 0xFF;
    782 			break;
    783 		case LINTR:
    784 		case LEXIT:
    785 		case LLEAVE:
    786 		case LSHELL:
    787 			quitenv(NULL);
    788 			unwind(i);
    789 			/* NOTREACHED */
    790 		default:
    791 			quitenv(NULL);
    792 			internal_errorf("%s %d", "CFUNC", i);
    793 		}
    794 		break;
    795 	}
    796 
    797 	/* executable command */
    798 	case CEXEC:
    799 	/* tracked alias */
    800 	case CTALIAS:
    801 		if (!(tp->flag&ISSET)) {
    802 			if (tp->u2.errnov == ENOENT) {
    803 				rv = 127;
    804 				warningf(true, "%s: %s", cp, "not found");
    805 			} else {
    806 				rv = 126;
    807 				warningf(true, "%s: %s: %s", cp, "can't execute",
    808 				    cstrerror(tp->u2.errnov));
    809 			}
    810 			break;
    811 		}
    812 
    813 		/* set $_ to programme's full path */
    814 		/* setstr() can't fail here */
    815 		setstr(typeset("_", LOCAL | EXPORT, 0, INTEGER, 0),
    816 		    tp->val.s, KSH_RETURN_ERROR);
    817 
    818 		if (flags&XEXEC) {
    819 			j_exit();
    820 			if (!(flags&XBGND)
    821 #ifndef MKSH_UNEMPLOYED
    822 			    || Flag(FMONITOR)
    823 #endif
    824 			    ) {
    825 				setexecsig(&sigtraps[SIGINT], SS_RESTORE_ORIG);
    826 				setexecsig(&sigtraps[SIGQUIT], SS_RESTORE_ORIG);
    827 			}
    828 		}
    829 
    830 		/* to fork we set up a TEXEC node and call execute */
    831 		texec.type = TEXEC;
    832 		/* for tprint */
    833 		texec.left = t;
    834 		texec.str = tp->val.s;
    835 		texec.args = ap;
    836 		rv = exchild(&texec, flags, xerrok, -1);
    837 		break;
    838 	}
    839  Leave:
    840 	if (flags & XEXEC) {
    841 		exstat = rv & 0xFF;
    842 		unwind(LLEAVE);
    843 	}
    844 	return (rv);
    845 }
    846 
    847 static void
    848 scriptexec(struct op *tp, const char **ap)
    849 {
    850 	const char *sh;
    851 #ifndef MKSH_SMALL
    852 	unsigned char *cp;
    853 	/* 64 == MAXINTERP in MirBSD <sys/param.h> */
    854 	char buf[64];
    855 	int fd;
    856 #endif
    857 	union mksh_ccphack args, cap;
    858 
    859 	sh = str_val(global("EXECSHELL"));
    860 	if (sh && *sh)
    861 		sh = search_path(sh, path, X_OK, NULL);
    862 	if (!sh || !*sh)
    863 		sh = MKSH_DEFAULT_EXECSHELL;
    864 
    865 	*tp->args-- = tp->str;
    866 
    867 #ifndef MKSH_SMALL
    868 	if ((fd = open(tp->str, O_RDONLY | O_BINARY)) >= 0) {
    869 		/* read first MAXINTERP octets from file */
    870 		if (read(fd, buf, sizeof(buf)) <= 0)
    871 			/* read error -> no good */
    872 			buf[0] = '\0';
    873 		close(fd);
    874 
    875 		/* skip UTF-8 Byte Order Mark, if present */
    876 		cp = (unsigned char *)buf;
    877 		if ((cp[0] == 0xEF) && (cp[1] == 0xBB) && (cp[2] == 0xBF))
    878 			cp += 3;
    879 		/* save begin of shebang for later */
    880 		fd = (char *)cp - buf;		/* either 0 or (if BOM) 3 */
    881 
    882 		/* scan for newline (or CR) or NUL _before_ end of buffer */
    883 		while ((size_t)((char *)cp - buf) < sizeof(buf))
    884 			if (*cp == '\0' || *cp == '\n' || *cp == '\r') {
    885 				*cp = '\0';
    886 				break;
    887 			} else
    888 				++cp;
    889 		/* if the shebang line is longer than MAXINTERP, bail out */
    890 		if ((size_t)((char *)cp - buf) >= sizeof(buf))
    891 			goto noshebang;
    892 
    893 		/* restore begin of shebang position (buf+0 or buf+3) */
    894 		cp = (unsigned char *)(buf + fd);
    895 		/* bail out if read error (above) or no shebang */
    896 		if ((cp[0] != '#') || (cp[1] != '!'))
    897 			goto noshebang;
    898 
    899 		cp += 2;
    900 		/* skip whitespace before shell name */
    901 		while (*cp == ' ' || *cp == '\t')
    902 			++cp;
    903 		/* just whitespace on the line? */
    904 		if (*cp == '\0')
    905 			goto noshebang;
    906 		/* no, we actually found an interpreter name */
    907 		sh = (char *)cp;
    908 		/* look for end of shell/interpreter name */
    909 		while (*cp != ' ' && *cp != '\t' && *cp != '\0')
    910 			++cp;
    911 		/* any arguments? */
    912 		if (*cp) {
    913 			*cp++ = '\0';
    914 			/* skip spaces before arguments */
    915 			while (*cp == ' ' || *cp == '\t')
    916 				++cp;
    917 			/* pass it all in ONE argument (historic reasons) */
    918 			if (*cp)
    919 				*tp->args-- = (char *)cp;
    920 		}
    921  noshebang:
    922 		if (buf[0] == 0x7F && buf[1] == 'E' && buf[2] == 'L' &&
    923 		    buf[3] == 'F')
    924 			errorf("%s: not executable: %d-bit ELF file", tp->str,
    925 			    32 * ((uint8_t)buf[4]));
    926 		fd = buf[0] << 8 | buf[1];
    927 		if ((fd == /* OMAGIC */ 0407) ||
    928 		    (fd == /* NMAGIC */ 0410) ||
    929 		    (fd == /* ZMAGIC */ 0413) ||
    930 		    (fd == /* QMAGIC */ 0314) ||
    931 		    (fd == /* ECOFF_I386 */ 0x4C01) ||
    932 		    (fd == /* ECOFF_M68K */ 0x0150 || fd == 0x5001) ||
    933 		    (fd == /* ECOFF_SH */   0x0500 || fd == 0x0005) ||
    934 		    (fd == /* "MZ" */ 0x4D5A) ||
    935 		    (fd == /* gzip */ 0x1F8B))
    936 			errorf("%s: not executable: magic %04X", tp->str, fd);
    937 	}
    938 #endif
    939 	args.ro = tp->args;
    940 	*args.ro = sh;
    941 
    942 	cap.ro = ap;
    943 	execve(args.rw[0], args.rw, cap.rw);
    944 
    945 	/* report both the programme that was run and the bogus interpreter */
    946 	errorf("%s: %s: %s", tp->str, sh, cstrerror(errno));
    947 }
    948 
    949 int
    950 shcomexec(const char **wp)
    951 {
    952 	struct tbl *tp;
    953 
    954 	tp = ktsearch(&builtins, *wp, hash(*wp));
    955 	return (call_builtin(tp, wp, "shcomexec"));
    956 }
    957 
    958 /*
    959  * Search function tables for a function. If create set, a table entry
    960  * is created if none is found.
    961  */
    962 struct tbl *
    963 findfunc(const char *name, uint32_t h, bool create)
    964 {
    965 	struct block *l;
    966 	struct tbl *tp = NULL;
    967 
    968 	for (l = e->loc; l; l = l->next) {
    969 		tp = ktsearch(&l->funs, name, h);
    970 		if (tp)
    971 			break;
    972 		if (!l->next && create) {
    973 			tp = ktenter(&l->funs, name, h);
    974 			tp->flag = DEFINED;
    975 			tp->type = CFUNC;
    976 			tp->val.t = NULL;
    977 			break;
    978 		}
    979 	}
    980 	return (tp);
    981 }
    982 
    983 /*
    984  * define function. Returns 1 if function is being undefined (t == 0) and
    985  * function did not exist, returns 0 otherwise.
    986  */
    987 int
    988 define(const char *name, struct op *t)
    989 {
    990 	uint32_t nhash;
    991 	struct tbl *tp;
    992 	bool was_set = false;
    993 
    994 	nhash = hash(name);
    995 
    996 	if (t != NULL && !tobool(t->u.ksh_func)) {
    997 		/* drop same-name aliases for POSIX functions */
    998 		if ((tp = ktsearch(&aliases, name, nhash)))
    999 			ktdelete(tp);
   1000 	}
   1001 
   1002 	while (/* CONSTCOND */ 1) {
   1003 		tp = findfunc(name, nhash, true);
   1004 		/* because findfunc:create=true */
   1005 		mkssert(tp != NULL);
   1006 
   1007 		if (tp->flag & ISSET)
   1008 			was_set = true;
   1009 		/*
   1010 		 * If this function is currently being executed, we zap
   1011 		 * this table entry so findfunc() won't see it
   1012 		 */
   1013 		if (tp->flag & FINUSE) {
   1014 			tp->name[0] = '\0';
   1015 			/* ensure it won't be found */
   1016 			tp->flag &= ~DEFINED;
   1017 			tp->flag |= FDELETE;
   1018 		} else
   1019 			break;
   1020 	}
   1021 
   1022 	if (tp->flag & ALLOC) {
   1023 		tp->flag &= ~(ISSET|ALLOC);
   1024 		tfree(tp->val.t, tp->areap);
   1025 	}
   1026 
   1027 	if (t == NULL) {
   1028 		/* undefine */
   1029 		ktdelete(tp);
   1030 		return (was_set ? 0 : 1);
   1031 	}
   1032 
   1033 	tp->val.t = tcopy(t->left, tp->areap);
   1034 	tp->flag |= (ISSET|ALLOC);
   1035 	if (t->u.ksh_func)
   1036 		tp->flag |= FKSH;
   1037 
   1038 	return (0);
   1039 }
   1040 
   1041 /*
   1042  * add builtin
   1043  */
   1044 const char *
   1045 builtin(const char *name, int (*func) (const char **))
   1046 {
   1047 	struct tbl *tp;
   1048 	uint32_t flag = DEFINED;
   1049 
   1050 	/* see if any flags should be set for this builtin */
   1051 	while (1) {
   1052 		if (*name == '=')
   1053 			/* command does variable assignment */
   1054 			flag |= KEEPASN;
   1055 		else if (*name == '*')
   1056 			/* POSIX special builtin */
   1057 			flag |= SPEC_BI;
   1058 		else
   1059 			break;
   1060 		name++;
   1061 	}
   1062 
   1063 	tp = ktenter(&builtins, name, hash(name));
   1064 	tp->flag = flag;
   1065 	tp->type = CSHELL;
   1066 	tp->val.f = func;
   1067 
   1068 	return (name);
   1069 }
   1070 
   1071 /*
   1072  * find command
   1073  * either function, hashed command, or built-in (in that order)
   1074  */
   1075 struct tbl *
   1076 findcom(const char *name, int flags)
   1077 {
   1078 	static struct tbl temp;
   1079 	uint32_t h = hash(name);
   1080 	struct tbl *tp = NULL, *tbi;
   1081 	/* insert if not found */
   1082 	unsigned char insert = Flag(FTRACKALL);
   1083 	/* for function autoloading */
   1084 	char *fpath;
   1085 	union mksh_cchack npath;
   1086 
   1087 	if (vstrchr(name, '/')) {
   1088 		insert = 0;
   1089 		/* prevent FPATH search below */
   1090 		flags &= ~FC_FUNC;
   1091 		goto Search;
   1092 	}
   1093 	tbi = (flags & FC_BI) ? ktsearch(&builtins, name, h) : NULL;
   1094 	/*
   1095 	 * POSIX says special builtins first, then functions, then
   1096 	 * regular builtins, then search path...
   1097 	 */
   1098 	if ((flags & FC_SPECBI) && tbi && (tbi->flag & SPEC_BI))
   1099 		tp = tbi;
   1100 	if (!tp && (flags & FC_FUNC)) {
   1101 		tp = findfunc(name, h, false);
   1102 		if (tp && !(tp->flag & ISSET)) {
   1103 			if ((fpath = str_val(global("FPATH"))) == null) {
   1104 				tp->u.fpath = NULL;
   1105 				tp->u2.errnov = ENOENT;
   1106 			} else
   1107 				tp->u.fpath = search_path(name, fpath, R_OK,
   1108 				    &tp->u2.errnov);
   1109 		}
   1110 	}
   1111 	if (!tp && (flags & FC_NORMBI) && tbi)
   1112 		tp = tbi;
   1113 	if (!tp && (flags & FC_PATH) && !(flags & FC_DEFPATH)) {
   1114 		tp = ktsearch(&taliases, name, h);
   1115 		if (tp && (tp->flag & ISSET) &&
   1116 		    ksh_access(tp->val.s, X_OK) != 0) {
   1117 			if (tp->flag & ALLOC) {
   1118 				tp->flag &= ~ALLOC;
   1119 				afree(tp->val.s, APERM);
   1120 			}
   1121 			tp->flag &= ~ISSET;
   1122 		}
   1123 	}
   1124 
   1125  Search:
   1126 	if ((!tp || (tp->type == CTALIAS && !(tp->flag&ISSET))) &&
   1127 	    (flags & FC_PATH)) {
   1128 		if (!tp) {
   1129 			if (insert && !(flags & FC_DEFPATH)) {
   1130 				tp = ktenter(&taliases, name, h);
   1131 				tp->type = CTALIAS;
   1132 			} else {
   1133 				tp = &temp;
   1134 				tp->type = CEXEC;
   1135 			}
   1136 			/* make ~ISSET */
   1137 			tp->flag = DEFINED;
   1138 		}
   1139 		npath.ro = search_path(name,
   1140 		    (flags & FC_DEFPATH) ? def_path : path,
   1141 		    X_OK, &tp->u2.errnov);
   1142 		if (npath.ro) {
   1143 			strdupx(tp->val.s, npath.ro, APERM);
   1144 			if (npath.ro != name)
   1145 				afree(npath.rw, ATEMP);
   1146 			tp->flag |= ISSET|ALLOC;
   1147 		} else if ((flags & FC_FUNC) &&
   1148 		    (fpath = str_val(global("FPATH"))) != null &&
   1149 		    (npath.ro = search_path(name, fpath, R_OK,
   1150 		    &tp->u2.errnov)) != NULL) {
   1151 			/*
   1152 			 * An undocumented feature of AT&T ksh is that
   1153 			 * it searches FPATH if a command is not found,
   1154 			 * even if the command hasn't been set up as an
   1155 			 * autoloaded function (ie, no typeset -uf).
   1156 			 */
   1157 			tp = &temp;
   1158 			tp->type = CFUNC;
   1159 			/* make ~ISSET */
   1160 			tp->flag = DEFINED;
   1161 			tp->u.fpath = npath.ro;
   1162 		}
   1163 	}
   1164 	return (tp);
   1165 }
   1166 
   1167 /*
   1168  * flush executable commands with relative paths
   1169  * (just relative or all?)
   1170  */
   1171 void
   1172 flushcom(bool all)
   1173 {
   1174 	struct tbl *tp;
   1175 	struct tstate ts;
   1176 
   1177 	for (ktwalk(&ts, &taliases); (tp = ktnext(&ts)) != NULL; )
   1178 		if ((tp->flag&ISSET) && (all || tp->val.s[0] != '/')) {
   1179 			if (tp->flag&ALLOC) {
   1180 				tp->flag &= ~(ALLOC|ISSET);
   1181 				afree(tp->val.s, APERM);
   1182 			}
   1183 			tp->flag &= ~ISSET;
   1184 		}
   1185 }
   1186 
   1187 /* check if path is something we want to find */
   1188 static int
   1189 search_access(const char *fn, int mode)
   1190 {
   1191 	struct stat sb;
   1192 
   1193 	if (stat(fn, &sb) < 0)
   1194 		/* file does not exist */
   1195 		return (ENOENT);
   1196 	/* LINTED use of access */
   1197 	if (access(fn, mode) < 0)
   1198 		/* file exists, but we can't access it */
   1199 		return (errno);
   1200 	if (mode == X_OK && (!S_ISREG(sb.st_mode) ||
   1201 	    !(sb.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH))))
   1202 		/* access(2) may say root can execute everything */
   1203 		return (S_ISDIR(sb.st_mode) ? EISDIR : EACCES);
   1204 	return (0);
   1205 }
   1206 
   1207 /*
   1208  * search for command with PATH
   1209  */
   1210 const char *
   1211 search_path(const char *name, const char *lpath,
   1212     /* R_OK or X_OK */
   1213     int mode,
   1214     /* set if candidate found, but not suitable */
   1215     int *errnop)
   1216 {
   1217 	const char *sp, *p;
   1218 	char *xp;
   1219 	XString xs;
   1220 	size_t namelen;
   1221 	int ec = 0, ev;
   1222 
   1223 	if (vstrchr(name, '/')) {
   1224 		if ((ec = search_access(name, mode)) == 0) {
   1225  search_path_ok:
   1226 			if (errnop)
   1227 				*errnop = 0;
   1228 			return (name);
   1229 		}
   1230 		goto search_path_err;
   1231 	}
   1232 
   1233 	namelen = strlen(name) + 1;
   1234 	Xinit(xs, xp, 128, ATEMP);
   1235 
   1236 	sp = lpath;
   1237 	while (sp != NULL) {
   1238 		xp = Xstring(xs, xp);
   1239 		if (!(p = cstrchr(sp, ':')))
   1240 			p = sp + strlen(sp);
   1241 		if (p != sp) {
   1242 			XcheckN(xs, xp, p - sp);
   1243 			memcpy(xp, sp, p - sp);
   1244 			xp += p - sp;
   1245 			*xp++ = '/';
   1246 		}
   1247 		sp = p;
   1248 		XcheckN(xs, xp, namelen);
   1249 		memcpy(xp, name, namelen);
   1250 		if ((ev = search_access(Xstring(xs, xp), mode)) == 0) {
   1251 			name = Xclose(xs, xp + namelen);
   1252 			goto search_path_ok;
   1253 		}
   1254 		/* accumulate non-ENOENT errors only */
   1255 		if (ev != ENOENT && ec == 0)
   1256 			ec = ev;
   1257 		if (*sp++ == '\0')
   1258 			sp = NULL;
   1259 	}
   1260 	Xfree(xs, xp);
   1261  search_path_err:
   1262 	if (errnop)
   1263 		*errnop = ec ? ec : ENOENT;
   1264 	return (NULL);
   1265 }
   1266 
   1267 static int
   1268 call_builtin(struct tbl *tp, const char **wp, const char *where)
   1269 {
   1270 	int rv;
   1271 
   1272 	if (!tp)
   1273 		internal_errorf("%s: %s", where, wp[0]);
   1274 	builtin_argv0 = wp[0];
   1275 	builtin_flag = tp->flag;
   1276 	shf_reopen(1, SHF_WR, shl_stdout);
   1277 	shl_stdout_ok = true;
   1278 	ksh_getopt_reset(&builtin_opt, GF_ERROR);
   1279 	rv = (*tp->val.f)(wp);
   1280 	shf_flush(shl_stdout);
   1281 	shl_stdout_ok = false;
   1282 	builtin_flag = 0;
   1283 	builtin_argv0 = NULL;
   1284 	return (rv);
   1285 }
   1286 
   1287 /*
   1288  * set up redirection, saving old fds in e->savefd
   1289  */
   1290 static int
   1291 iosetup(struct ioword *iop, struct tbl *tp)
   1292 {
   1293 	int u = -1;
   1294 	char *cp = iop->name;
   1295 	int iotype = iop->flag & IOTYPE;
   1296 	bool do_open = true, do_close = false;
   1297 	int flags = 0;
   1298 	struct ioword iotmp;
   1299 	struct stat statb;
   1300 
   1301 	if (iotype != IOHERE)
   1302 		cp = evalonestr(cp, DOTILDE|(Flag(FTALKING_I) ? DOGLOB : 0));
   1303 
   1304 	/* Used for tracing and error messages to print expanded cp */
   1305 	iotmp = *iop;
   1306 	iotmp.name = (iotype == IOHERE) ? NULL : cp;
   1307 	iotmp.flag |= IONAMEXP;
   1308 
   1309 	if (Flag(FXTRACE)) {
   1310 		change_xtrace(2, false);
   1311 		fptreef(shl_xtrace, 0, "%R", &iotmp);
   1312 		change_xtrace(1, false);
   1313 	}
   1314 
   1315 	switch (iotype) {
   1316 	case IOREAD:
   1317 		flags = O_RDONLY;
   1318 		break;
   1319 
   1320 	case IOCAT:
   1321 		flags = O_WRONLY | O_APPEND | O_CREAT;
   1322 		break;
   1323 
   1324 	case IOWRITE:
   1325 		flags = O_WRONLY | O_CREAT | O_TRUNC;
   1326 		/*
   1327 		 * The stat() is here to allow redirections to
   1328 		 * things like /dev/null without error.
   1329 		 */
   1330 		if (Flag(FNOCLOBBER) && !(iop->flag & IOCLOB) &&
   1331 		    (stat(cp, &statb) < 0 || S_ISREG(statb.st_mode)))
   1332 			flags |= O_EXCL;
   1333 		break;
   1334 
   1335 	case IORDWR:
   1336 		flags = O_RDWR | O_CREAT;
   1337 		break;
   1338 
   1339 	case IOHERE:
   1340 		do_open = false;
   1341 		/* herein() returns -2 if error has been printed */
   1342 		u = herein(iop, NULL);
   1343 		/* cp may have wrong name */
   1344 		break;
   1345 
   1346 	case IODUP: {
   1347 		const char *emsg;
   1348 
   1349 		do_open = false;
   1350 		if (*cp == '-' && !cp[1]) {
   1351 			/* prevent error return below */
   1352 			u = 1009;
   1353 			do_close = true;
   1354 		} else if ((u = check_fd(cp,
   1355 		    X_OK | ((iop->flag & IORDUP) ? R_OK : W_OK),
   1356 		    &emsg)) < 0) {
   1357 			char *sp;
   1358 
   1359 			warningf(true, "%s: %s",
   1360 			    (sp = snptreef(NULL, 32, "%R", &iotmp)), emsg);
   1361 			afree(sp, ATEMP);
   1362 			return (-1);
   1363 		}
   1364 		if (u == iop->unit)
   1365 			/* "dup from" == "dup to" */
   1366 			return (0);
   1367 		break;
   1368 	    }
   1369 	}
   1370 
   1371 	if (do_open) {
   1372 		if (Flag(FRESTRICTED) && (flags & O_CREAT)) {
   1373 			warningf(true, "%s: %s", cp, "restricted");
   1374 			return (-1);
   1375 		}
   1376 		u = open(cp, flags | O_BINARY, 0666);
   1377 	}
   1378 	if (u < 0) {
   1379 		/* herein() may already have printed message */
   1380 		if (u == -1) {
   1381 			u = errno;
   1382 			warningf(true, "can't %s %s: %s",
   1383 			    iotype == IODUP ? "dup" :
   1384 			    (iotype == IOREAD || iotype == IOHERE) ?
   1385 			    "open" : "create", cp, cstrerror(u));
   1386 		}
   1387 		return (-1);
   1388 	}
   1389 	/* Do not save if it has already been redirected (i.e. "cat >x >y"). */
   1390 	if (e->savefd[iop->unit] == 0) {
   1391 		/* If these are the same, it means unit was previously closed */
   1392 		if (u == iop->unit)
   1393 			e->savefd[iop->unit] = -1;
   1394 		else
   1395 			/*
   1396 			 * c_exec() assumes e->savefd[fd] set for any
   1397 			 * redirections. Ask savefd() not to close iop->unit;
   1398 			 * this allows error messages to be seen if iop->unit
   1399 			 * is 2; also means we can't lose the fd (eg, both
   1400 			 * dup2 below and dup2 in restfd() failing).
   1401 			 */
   1402 			e->savefd[iop->unit] = savefd(iop->unit);
   1403 	}
   1404 
   1405 	if (do_close)
   1406 		close(iop->unit);
   1407 	else if (u != iop->unit) {
   1408 		if (ksh_dup2(u, iop->unit, true) < 0) {
   1409 			int eno;
   1410 			char *sp;
   1411 
   1412 			eno = errno;
   1413 			warningf(true, "%s %s %s",
   1414 			    "can't finish (dup) redirection",
   1415 			    (sp = snptreef(NULL, 32, "%R", &iotmp)),
   1416 			    cstrerror(eno));
   1417 			afree(sp, ATEMP);
   1418 			if (iotype != IODUP)
   1419 				close(u);
   1420 			return (-1);
   1421 		}
   1422 		if (iotype != IODUP)
   1423 			close(u);
   1424 		/*
   1425 		 * Touching any co-process fd in an empty exec
   1426 		 * causes the shell to close its copies
   1427 		 */
   1428 		else if (tp && tp->type == CSHELL && tp->val.f == c_exec) {
   1429 			if (iop->flag & IORDUP)
   1430 				/* possible exec <&p */
   1431 				coproc_read_close(u);
   1432 			else
   1433 				/* possible exec >&p */
   1434 				coproc_write_close(u);
   1435 		}
   1436 	}
   1437 	if (u == 2)
   1438 		/* Clear any write errors */
   1439 		shf_reopen(2, SHF_WR, shl_out);
   1440 	return (0);
   1441 }
   1442 
   1443 /*
   1444  * Process here documents by providing the content, either as
   1445  * result (globally allocated) string or in a temp file; if
   1446  * unquoted, the string is expanded first.
   1447  */
   1448 static int
   1449 hereinval(const char *content, int sub, char **resbuf, struct shf *shf)
   1450 {
   1451 	const char * volatile ccp = content;
   1452 	struct source *s, *osource;
   1453 
   1454 	osource = source;
   1455 	newenv(E_ERRH);
   1456 	if (kshsetjmp(e->jbuf)) {
   1457 		source = osource;
   1458 		quitenv(shf);
   1459 		/* special to iosetup(): don't print error */
   1460 		return (-2);
   1461 	}
   1462 	if (sub) {
   1463 		/* do substitutions on the content of heredoc */
   1464 		s = pushs(SSTRING, ATEMP);
   1465 		s->start = s->str = ccp;
   1466 		source = s;
   1467 		if (yylex(sub) != LWORD)
   1468 			internal_errorf("%s: %s", "herein", "yylex");
   1469 		source = osource;
   1470 		ccp = evalstr(yylval.cp, 0);
   1471 	}
   1472 
   1473 	if (resbuf == NULL)
   1474 		shf_puts(ccp, shf);
   1475 	else
   1476 		strdupx(*resbuf, ccp, APERM);
   1477 
   1478 	quitenv(NULL);
   1479 	return (0);
   1480 }
   1481 
   1482 static int
   1483 herein(struct ioword *iop, char **resbuf)
   1484 {
   1485 	int fd = -1;
   1486 	struct shf *shf;
   1487 	struct temp *h;
   1488 	int i;
   1489 
   1490 	/* ksh -c 'cat << EOF' can cause this... */
   1491 	if (iop->heredoc == NULL) {
   1492 		warningf(true, "%s missing", "here document");
   1493 		/* special to iosetup(): don't print error */
   1494 		return (-2);
   1495 	}
   1496 
   1497 	/* lexer substitution flags */
   1498 	i = (iop->flag & IOEVAL) ? (ONEWORD | HEREDOC) : 0;
   1499 
   1500 	/* skip all the fd setup if we just want the value */
   1501 	if (resbuf != NULL)
   1502 		return (hereinval(iop->heredoc, i, resbuf, NULL));
   1503 
   1504 	/*
   1505 	 * Create temp file to hold content (done before newenv
   1506 	 * so temp doesn't get removed too soon).
   1507 	 */
   1508 	h = maketemp(ATEMP, TT_HEREDOC_EXP, &e->temps);
   1509 	if (!(shf = h->shf) || (fd = open(h->tffn, O_RDONLY | O_BINARY, 0)) < 0) {
   1510 		i = errno;
   1511 		warningf(true, "can't %s temporary file %s: %s",
   1512 		    !shf ? "create" : "open", h->tffn, cstrerror(i));
   1513 		if (shf)
   1514 			shf_close(shf);
   1515 		/* special to iosetup(): don't print error */
   1516 		return (-2);
   1517 	}
   1518 
   1519 	if (hereinval(iop->heredoc, i, NULL, shf) == -2) {
   1520 		close(fd);
   1521 		/* special to iosetup(): don't print error */
   1522 		return (-2);
   1523 	}
   1524 
   1525 	if (shf_close(shf) == EOF) {
   1526 		i = errno;
   1527 		close(fd);
   1528 		warningf(true, "can't %s temporary file %s: %s",
   1529 		    "write", h->tffn, cstrerror(i));
   1530 		/* special to iosetup(): don't print error */
   1531 		return (-2);
   1532 	}
   1533 
   1534 	return (fd);
   1535 }
   1536 
   1537 /*
   1538  *	ksh special - the select command processing section
   1539  *	print the args in column form - assuming that we can
   1540  */
   1541 static const char *
   1542 do_selectargs(const char **ap, bool print_menu)
   1543 {
   1544 	static const char *read_args[] = {
   1545 		"read", "-r", "REPLY", NULL
   1546 	};
   1547 	char *s;
   1548 	int i, argct;
   1549 
   1550 	for (argct = 0; ap[argct]; argct++)
   1551 		;
   1552 	while (/* CONSTCOND */ 1) {
   1553 		/*-
   1554 		 * Menu is printed if
   1555 		 *	- this is the first time around the select loop
   1556 		 *	- the user enters a blank line
   1557 		 *	- the REPLY parameter is empty
   1558 		 */
   1559 		if (print_menu || !*str_val(global("REPLY")))
   1560 			pr_menu(ap);
   1561 		shellf("%s", str_val(global("PS3")));
   1562 		if (call_builtin(findcom("read", FC_BI), read_args, Tselect))
   1563 			return (NULL);
   1564 		s = str_val(global("REPLY"));
   1565 		if (*s && getn(s, &i))
   1566 			return ((i >= 1 && i <= argct) ? ap[i - 1] : null);
   1567 		print_menu = true;
   1568 	}
   1569 }
   1570 
   1571 struct select_menu_info {
   1572 	const char * const *args;
   1573 	int num_width;
   1574 };
   1575 
   1576 /* format a single select menu item */
   1577 static char *
   1578 select_fmt_entry(char *buf, size_t buflen, unsigned int i, const void *arg)
   1579 {
   1580 	const struct select_menu_info *smi =
   1581 	    (const struct select_menu_info *)arg;
   1582 
   1583 	shf_snprintf(buf, buflen, "%*u) %s",
   1584 	    smi->num_width, i + 1, smi->args[i]);
   1585 	return (buf);
   1586 }
   1587 
   1588 /*
   1589  *	print a select style menu
   1590  */
   1591 void
   1592 pr_menu(const char * const *ap)
   1593 {
   1594 	struct select_menu_info smi;
   1595 	const char * const *pp;
   1596 	size_t acols = 0, aocts = 0, i;
   1597 	unsigned int n;
   1598 
   1599 	/*
   1600 	 * width/column calculations were done once and saved, but this
   1601 	 * means select can't be used recursively so we re-calculate
   1602 	 * each time (could save in a structure that is returned, but
   1603 	 * it's probably not worth the bother)
   1604 	 */
   1605 
   1606 	/*
   1607 	 * get dimensions of the list
   1608 	 */
   1609 	for (n = 0, pp = ap; *pp; n++, pp++) {
   1610 		i = strlen(*pp);
   1611 		if (i > aocts)
   1612 			aocts = i;
   1613 		i = utf_mbswidth(*pp);
   1614 		if (i > acols)
   1615 			acols = i;
   1616 	}
   1617 
   1618 	/*
   1619 	 * we will print an index of the form "%d) " in front of
   1620 	 * each entry, so get the maximum width of this
   1621 	 */
   1622 	for (i = n, smi.num_width = 1; i >= 10; i /= 10)
   1623 		smi.num_width++;
   1624 
   1625 	smi.args = ap;
   1626 	print_columns(shl_out, n, select_fmt_entry, (void *)&smi,
   1627 	    smi.num_width + 2 + aocts, smi.num_width + 2 + acols,
   1628 	    true);
   1629 }
   1630 
   1631 static char *
   1632 plain_fmt_entry(char *buf, size_t buflen, unsigned int i, const void *arg)
   1633 {
   1634 	strlcpy(buf, ((const char * const *)arg)[i], buflen);
   1635 	return (buf);
   1636 }
   1637 
   1638 void
   1639 pr_list(char * const *ap)
   1640 {
   1641 	size_t acols = 0, aocts = 0, i;
   1642 	unsigned int n;
   1643 	char * const *pp;
   1644 
   1645 	for (n = 0, pp = ap; *pp; n++, pp++) {
   1646 		i = strlen(*pp);
   1647 		if (i > aocts)
   1648 			aocts = i;
   1649 		i = utf_mbswidth(*pp);
   1650 		if (i > acols)
   1651 			acols = i;
   1652 	}
   1653 
   1654 	print_columns(shl_out, n, plain_fmt_entry, (const void *)ap,
   1655 	    aocts, acols, false);
   1656 }
   1657 
   1658 /*
   1659  *	[[ ... ]] evaluation routines
   1660  */
   1661 
   1662 /*
   1663  * Test if the current token is a whatever. Accepts the current token if
   1664  * it is. Returns 0 if it is not, non-zero if it is (in the case of
   1665  * TM_UNOP and TM_BINOP, the returned value is a Test_op).
   1666  */
   1667 static Test_op
   1668 dbteste_isa(Test_env *te, Test_meta meta)
   1669 {
   1670 	Test_op ret = TO_NONOP;
   1671 	bool uqword;
   1672 	const char *p;
   1673 
   1674 	if (!*te->pos.wp)
   1675 		return (meta == TM_END ? TO_NONNULL : TO_NONOP);
   1676 
   1677 	/* unquoted word? */
   1678 	for (p = *te->pos.wp; *p == CHAR; p += 2)
   1679 		;
   1680 	uqword = *p == EOS;
   1681 
   1682 	if (meta == TM_UNOP || meta == TM_BINOP) {
   1683 		if (uqword) {
   1684 			/* longer than the longest operator */
   1685 			char buf[8];
   1686 			char *q = buf;
   1687 
   1688 			p = *te->pos.wp;
   1689 			while (*p++ == CHAR &&
   1690 			    (size_t)(q - buf) < sizeof(buf) - 1)
   1691 				*q++ = *p++;
   1692 			*q = '\0';
   1693 			ret = test_isop(meta, buf);
   1694 		}
   1695 	} else if (meta == TM_END)
   1696 		ret = TO_NONOP;
   1697 	else
   1698 		ret = (uqword && !strcmp(*te->pos.wp,
   1699 		    dbtest_tokens[(int)meta])) ? TO_NONNULL : TO_NONOP;
   1700 
   1701 	/* Accept the token? */
   1702 	if (ret != TO_NONOP)
   1703 		te->pos.wp++;
   1704 
   1705 	return (ret);
   1706 }
   1707 
   1708 static const char *
   1709 dbteste_getopnd(Test_env *te, Test_op op, bool do_eval)
   1710 {
   1711 	const char *s = *te->pos.wp;
   1712 
   1713 	if (!s)
   1714 		return (NULL);
   1715 
   1716 	te->pos.wp++;
   1717 
   1718 	if (!do_eval)
   1719 		return (null);
   1720 
   1721 	if (op == TO_STEQL || op == TO_STNEQ)
   1722 		s = evalstr(s, DOTILDE | DOPAT);
   1723 	else
   1724 		s = evalstr(s, DOTILDE);
   1725 
   1726 	return (s);
   1727 }
   1728 
   1729 static void
   1730 dbteste_error(Test_env *te, int offset, const char *msg)
   1731 {
   1732 	te->flags |= TEF_ERROR;
   1733 	internal_warningf("dbteste_error: %s (offset %d)", msg, offset);
   1734 }
   1735