1 /*	$OpenBSD: main.c,v 1.57 2015/09/10 22:48:58 nicm Exp $	*/
2 /*	$OpenBSD: tty.c,v 1.10 2014/08/10 02:44:26 guenther Exp $	*/
3 /*	$OpenBSD: io.c,v 1.26 2015/09/11 08:00:27 guenther Exp $	*/
4 /*	$OpenBSD: table.c,v 1.16 2015/09/01 13:12:31 tedu Exp $	*/
5 
6 /*-
7  * Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
8  *		 2011, 2012, 2013, 2014, 2015, 2016
9  *	mirabilos <m@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 1.322 2016/11/11 23:48:30 tg Exp $");
38 
39 extern char **environ;
40 
41 #ifndef MKSHRC_PATH
42 #define MKSHRC_PATH	"~/.mkshrc"
43 #endif
44 
45 #ifndef MKSH_DEFAULT_TMPDIR
46 #define MKSH_DEFAULT_TMPDIR	MKSH_UNIXROOT "/tmp"
47 #endif
48 
49 static uint8_t isuc(const char *);
50 static int main_init(int, const char *[], Source **, struct block **);
51 void chvt_reinit(void);
52 static void reclaim(void);
53 static void remove_temps(struct temp *);
54 static mksh_uari_t rndsetup(void);
55 #ifdef SIGWINCH
56 static void x_sigwinch(int);
57 #endif
58 
59 static const char initifs[] = "IFS= \t\n";
60 
61 static const char initsubs[] =
62     "${PS2=> }"
63     "${PS3=#? }"
64     "${PS4=+ }"
65     "${SECONDS=0}"
66     "${TMOUT=0}"
67     "${EPOCHREALTIME=}";
68 
69 static const char *initcoms[] = {
70 	Ttypeset, "-r", initvsn, NULL,
71 	Ttypeset, "-x", "HOME", TPATH, TSHELL, NULL,
72 	Ttypeset, "-i10", "COLUMNS", "LINES", "SECONDS", "TMOUT", NULL,
73 	Talias,
74 	"integer=\\typeset -i",
75 	"local=\\typeset",
76 	/* not "alias -t --": hash -r needs to work */
77 	"hash=\\builtin alias -t",
78 	"type=\\builtin whence -v",
79 	"autoload=\\typeset -fu",
80 	"functions=\\typeset -f",
81 	"history=\\builtin fc -l",
82 	"nameref=\\typeset -n",
83 	"nohup=nohup ",
84 	"r=\\builtin fc -e -",
85 	"login=\\exec login",
86 	NULL,
87 	 /* this is what AT&T ksh seems to track, with the addition of emacs */
88 	Talias, "-tU",
89 	Tcat, "cc", "chmod", "cp", "date", "ed", "emacs", "grep", "ls",
90 	"make", "mv", "pr", "rm", "sed", Tsh, "vi", "who", NULL,
91 	NULL
92 };
93 
94 static const char *restr_com[] = {
95 	Ttypeset, "-r", TPATH, "ENV", TSHELL, NULL
96 };
97 
98 static bool initio_done;
99 
100 /* top-level parsing and execution environment */
101 static struct env env;
102 struct env *e = &env;
103 
104 static mksh_uari_t
rndsetup(void)105 rndsetup(void)
106 {
107 	register uint32_t h;
108 	struct {
109 		ALLOC_ITEM alloc_INT;
110 		void *dataptr, *stkptr, *mallocptr;
111 #if defined(__GLIBC__) && (__GLIBC__ >= 2)
112 		sigjmp_buf jbuf;
113 #endif
114 		struct timeval tv;
115 	} *bufptr;
116 	char *cp;
117 
118 	cp = alloc(sizeof(*bufptr) - sizeof(ALLOC_ITEM), APERM);
119 	/* clear the allocated space, for valgrind and to avoid UB */
120 	memset(cp, 0, sizeof(*bufptr) - sizeof(ALLOC_ITEM));
121 	/* undo what alloc() did to the malloc result address */
122 	bufptr = (void *)(cp - sizeof(ALLOC_ITEM));
123 	/* PIE or something similar provides us with deltas here */
124 	bufptr->dataptr = &rndsetupstate;
125 	/* ASLR in at least Windows, Linux, some BSDs */
126 	bufptr->stkptr = &bufptr;
127 	/* randomised malloc in BSD (and possibly others) */
128 	bufptr->mallocptr = bufptr;
129 #if defined(__GLIBC__) && (__GLIBC__ >= 2)
130 	/* glibc pointer guard */
131 	sigsetjmp(bufptr->jbuf, 1);
132 #endif
133 	/* introduce variation (and yes, second arg MBZ for portability) */
134 	mksh_TIME(bufptr->tv);
135 
136 #ifdef MKSH_ALLOC_CATCH_UNDERRUNS
137 	mprotect(((char *)bufptr) + 4096, 4096, PROT_READ | PROT_WRITE);
138 #endif
139 	h = chvt_rndsetup(bufptr, sizeof(*bufptr));
140 
141 	afree(cp, APERM);
142 	return ((mksh_uari_t)h);
143 }
144 
145 void
chvt_reinit(void)146 chvt_reinit(void)
147 {
148 	kshpid = procpid = getpid();
149 	ksheuid = geteuid();
150 	kshpgrp = getpgrp();
151 	kshppid = getppid();
152 }
153 
154 static const char *empty_argv[] = {
155 	Tmksh, NULL
156 };
157 
158 static uint8_t
isuc(const char * cx)159 isuc(const char *cx) {
160 	char *cp, *x;
161 	uint8_t rv = 0;
162 
163 	if (!cx || !*cx)
164 		return (0);
165 
166 	/* uppercase a string duplicate */
167 	strdupx(x, cx, ATEMP);
168 	cp = x;
169 	while ((*cp = ksh_toupper(*cp)))
170 		++cp;
171 
172 	/* check for UTF-8 */
173 	if (strstr(x, "UTF-8") || strstr(x, "UTF8"))
174 		rv = 1;
175 
176 	/* free copy and out */
177 	afree(x, ATEMP);
178 	return (rv);
179 }
180 
181 static int
main_init(int argc,const char * argv[],Source ** sp,struct block ** lp)182 main_init(int argc, const char *argv[], Source **sp, struct block **lp)
183 {
184 	int argi, i;
185 	Source *s = NULL;
186 	struct block *l;
187 	unsigned char restricted_shell, errexit, utf_flag;
188 	char *cp;
189 	const char *ccp, **wp;
190 	struct tbl *vp;
191 	struct stat s_stdin;
192 #if !defined(_PATH_DEFPATH) && defined(_CS_PATH)
193 	ssize_t k;
194 #endif
195 
196 #ifdef __OS2__
197 	for (i = 0; i < 3; ++i)
198 		if (!isatty(i))
199 			setmode(i, O_BINARY);
200 #endif
201 
202 	/* do things like getpgrp() et al. */
203 	chvt_reinit();
204 
205 	/* make sure argv[] is sane, for weird OSes */
206 	if (!*argv) {
207 		argv = empty_argv;
208 		argc = 1;
209 	}
210 	kshname = argv[0];
211 
212 	/* initialise permanent Area */
213 	ainit(&aperm);
214 	/* max. name length: -2147483648 = 11 (+ NUL) */
215 	vtemp = alloc(offsetof(struct tbl, name[0]) + 12, APERM);
216 
217 	/* set up base environment */
218 	env.type = E_NONE;
219 	ainit(&env.area);
220 	/* set up global l->vars and l->funs */
221 	newblock();
222 
223 	/* Do this first so output routines (eg, errorf, shellf) can work */
224 	initio();
225 
226 	/* determine the basename (without '-' or path) of the executable */
227 	ccp = kshname;
228 	goto begin_parsing_kshname;
229 	while ((i = ccp[argi++])) {
230 		if (mksh_cdirsep(i)) {
231 			ccp += argi;
232  begin_parsing_kshname:
233 			argi = 0;
234 			if (*ccp == '-')
235 				++ccp;
236 		}
237 	}
238 	if (!*ccp)
239 		ccp = empty_argv[0];
240 
241 	/*
242 	 * Turn on nohup by default. (AT&T ksh does not have a nohup
243 	 * option - it always sends the hup).
244 	 */
245 	Flag(FNOHUP) = 1;
246 
247 	/*
248 	 * Turn on brace expansion by default. AT&T kshs that have
249 	 * alternation always have it on.
250 	 */
251 	Flag(FBRACEEXPAND) = 1;
252 
253 	/*
254 	 * Turn on "set -x" inheritance by default.
255 	 */
256 	Flag(FXTRACEREC) = 1;
257 
258 	/* define built-in commands and see if we were called as one */
259 	ktinit(APERM, &builtins,
260 	    /* currently up to 54 builtins: 75% of 128 = 2^7 */
261 	    7);
262 	for (i = 0; mkshbuiltins[i].name != NULL; i++)
263 		if (!strcmp(ccp, builtin(mkshbuiltins[i].name,
264 		    mkshbuiltins[i].func)))
265 			Flag(FAS_BUILTIN) = 1;
266 
267 	if (!Flag(FAS_BUILTIN)) {
268 		/* check for -T option early */
269 		argi = parse_args(argv, OF_FIRSTTIME, NULL);
270 		if (argi < 0)
271 			return (1);
272 
273 #if defined(MKSH_BINSHPOSIX) || defined(MKSH_BINSHREDUCED)
274 		/* are we called as -sh or /bin/sh or so? */
275 		if (!strcmp(ccp, "sh" MKSH_EXE_EXT)) {
276 			/* either also turns off braceexpand */
277 #ifdef MKSH_BINSHPOSIX
278 			/* enable better POSIX conformance */
279 			change_flag(FPOSIX, OF_FIRSTTIME, true);
280 #endif
281 #ifdef MKSH_BINSHREDUCED
282 			/* enable kludge/compat mode */
283 			change_flag(FSH, OF_FIRSTTIME, true);
284 #endif
285 		}
286 #endif
287 	}
288 
289 	initvar();
290 
291 	initctypes();
292 
293 	inittraps();
294 
295 	coproc_init();
296 
297 	/* set up variable and command dictionaries */
298 	ktinit(APERM, &taliases, 0);
299 	ktinit(APERM, &aliases, 0);
300 #ifndef MKSH_NOPWNAM
301 	ktinit(APERM, &homedirs, 0);
302 #endif
303 
304 	/* define shell keywords */
305 	initkeywords();
306 
307 	init_histvec();
308 
309 	/* initialise tty size before importing environment */
310 	change_winsz();
311 
312 #ifdef _PATH_DEFPATH
313 	def_path = _PATH_DEFPATH;
314 #else
315 #ifdef _CS_PATH
316 	if ((k = confstr(_CS_PATH, NULL, 0)) > 0 &&
317 	    confstr(_CS_PATH, cp = alloc(k + 1, APERM), k + 1) == k + 1)
318 		def_path = cp;
319 	else
320 #endif
321 		/*
322 		 * this is uniform across all OSes unless it
323 		 * breaks somewhere hard; don't try to optimise,
324 		 * e.g. add stuff for Interix or remove /usr
325 		 * for HURD, because e.g. Debian GNU/HURD is
326 		 * "keeping a regular /usr"; this is supposed
327 		 * to be a sane 'basic' default PATH
328 		 */
329 		def_path = MKSH_UNIXROOT "/bin" MKSH_PATHSEPS
330 		    MKSH_UNIXROOT "/usr/bin" MKSH_PATHSEPS
331 		    MKSH_UNIXROOT "/sbin" MKSH_PATHSEPS
332 		    MKSH_UNIXROOT "/usr/sbin";
333 #endif
334 
335 	/*
336 	 * Set PATH to def_path (will set the path global variable).
337 	 * (import of environment below will probably change this setting).
338 	 */
339 	vp = global(TPATH);
340 	/* setstr can't fail here */
341 	setstr(vp, def_path, KSH_RETURN_ERROR);
342 
343 #ifndef MKSH_NO_CMDLINE_EDITING
344 	/*
345 	 * Set edit mode to emacs by default, may be overridden
346 	 * by the environment or the user. Also, we want tab completion
347 	 * on in vi by default.
348 	 */
349 	change_flag(FEMACS, OF_SPECIAL, true);
350 #if !MKSH_S_NOVI
351 	Flag(FVITABCOMPLETE) = 1;
352 #endif
353 #endif
354 
355 	/* import environment */
356 	if (environ != NULL) {
357 		wp = (const char **)environ;
358 		while (*wp != NULL) {
359 			rndpush(*wp);
360 			typeset(*wp, IMPORT | EXPORT, 0, 0, 0);
361 			++wp;
362 		}
363 	}
364 
365 	/* override default PATH regardless of environment */
366 #ifdef MKSH_DEFPATH_OVERRIDE
367 	 vp = global(TPATH);
368 	 setstr(vp, MKSH_DEFPATH_OVERRIDE, KSH_RETURN_ERROR);
369 #endif
370 
371 	/* for security */
372 	typeset(initifs, 0, 0, 0, 0);
373 
374 	/* assign default shell variable values */
375 	substitute(initsubs, 0);
376 
377 	/* Figure out the current working directory and set $PWD */
378 	vp = global(TPWD);
379 	cp = str_val(vp);
380 	/* Try to use existing $PWD if it is valid */
381 	set_current_wd((mksh_abspath(cp) && test_eval(NULL, TO_FILEQ, cp,
382 	    Tdot, true)) ? cp : NULL);
383 	if (current_wd[0])
384 		simplify_path(current_wd);
385 	/* Only set pwd if we know where we are or if it had a bogus value */
386 	if (current_wd[0] || *cp)
387 		/* setstr can't fail here */
388 		setstr(vp, current_wd, KSH_RETURN_ERROR);
389 
390 	for (wp = initcoms; *wp != NULL; wp++) {
391 		shcomexec(wp);
392 		while (*wp != NULL)
393 			wp++;
394 	}
395 	setint_n(global("OPTIND"), 1, 10);
396 
397 	kshuid = getuid();
398 	kshgid = getgid();
399 	kshegid = getegid();
400 
401 	safe_prompt = ksheuid ? "$ " : "# ";
402 	vp = global("PS1");
403 	/* Set PS1 if unset or we are root and prompt doesn't contain a # */
404 	if (!(vp->flag & ISSET) ||
405 	    (!ksheuid && !strchr(str_val(vp), '#')))
406 		/* setstr can't fail here */
407 		setstr(vp, safe_prompt, KSH_RETURN_ERROR);
408 	setint_n((vp = global("BASHPID")), 0, 10);
409 	vp->flag |= INT_U;
410 	setint_n((vp = global("PGRP")), (mksh_uari_t)kshpgrp, 10);
411 	vp->flag |= INT_U;
412 	setint_n((vp = global("PPID")), (mksh_uari_t)kshppid, 10);
413 	vp->flag |= INT_U;
414 	setint_n((vp = global("USER_ID")), (mksh_uari_t)ksheuid, 10);
415 	vp->flag |= INT_U;
416 	setint_n((vp = global("KSHUID")), (mksh_uari_t)kshuid, 10);
417 	vp->flag |= INT_U;
418 	setint_n((vp = global("KSHEGID")), (mksh_uari_t)kshegid, 10);
419 	vp->flag |= INT_U;
420 	setint_n((vp = global("KSHGID")), (mksh_uari_t)kshgid, 10);
421 	vp->flag |= INT_U;
422 	setint_n((vp = global("RANDOM")), rndsetup(), 10);
423 	vp->flag |= INT_U;
424 	setint_n((vp_pipest = global("PIPESTATUS")), 0, 10);
425 
426 	/* Set this before parsing arguments */
427 	Flag(FPRIVILEGED) = (kshuid != ksheuid || kshgid != kshegid) ? 2 : 0;
428 
429 	/* this to note if monitor is set on command line (see below) */
430 #ifndef MKSH_UNEMPLOYED
431 	Flag(FMONITOR) = 127;
432 #endif
433 	/* this to note if utf-8 mode is set on command line (see below) */
434 	UTFMODE = 2;
435 
436 	if (!Flag(FAS_BUILTIN)) {
437 		argi = parse_args(argv, OF_CMDLINE, NULL);
438 		if (argi < 0)
439 			return (1);
440 	}
441 
442 	/* process this later only, default to off (hysterical raisins) */
443 	utf_flag = UTFMODE;
444 	UTFMODE = 0;
445 
446 	if (Flag(FAS_BUILTIN)) {
447 		/* auto-detect from environment variables, always */
448 		utf_flag = 3;
449 	} else if (Flag(FCOMMAND)) {
450 		s = pushs(SSTRINGCMDLINE, ATEMP);
451 		if (!(s->start = s->str = argv[argi++]))
452 			errorf(Tf_optfoo, "", "", 'c', Treq_arg);
453 		while (*s->str) {
454 			if (*s->str != ' ' && ctype(*s->str, C_QUOTE))
455 				break;
456 			s->str++;
457 		}
458 		if (!*s->str)
459 			s->flags |= SF_MAYEXEC;
460 		s->str = s->start;
461 #ifdef MKSH_MIDNIGHTBSD01ASH_COMPAT
462 		/* compatibility to MidnightBSD 0.1 /bin/sh (kludge) */
463 		if (Flag(FSH) && argv[argi] && !strcmp(argv[argi], "--"))
464 			++argi;
465 #endif
466 		if (argv[argi])
467 			kshname = argv[argi++];
468 	} else if (argi < argc && !Flag(FSTDIN)) {
469 		s = pushs(SFILE, ATEMP);
470 #ifdef __OS2__
471 		/*
472 		 * A bug in OS/2 extproc (like shebang) handling makes
473 		 * it not pass the full pathname of a script, so we need
474 		 * to search for it. This changes the behaviour of a
475 		 * simple "mksh foo", but can't be helped.
476 		 */
477 		s->file = search_path(argv[argi++], path, X_OK, NULL);
478 		if (!s->file || !*s->file)
479 			s->file = argv[argi - 1];
480 #else
481 		s->file = argv[argi++];
482 #endif
483 		s->u.shf = shf_open(s->file, O_RDONLY, 0,
484 		    SHF_MAPHI | SHF_CLEXEC);
485 		if (s->u.shf == NULL) {
486 			shl_stdout_ok = false;
487 			warningf(true, Tf_sD_s, s->file, cstrerror(errno));
488 			/* mandated by SUSv4 */
489 			exstat = 127;
490 			unwind(LERROR);
491 		}
492 		kshname = s->file;
493 	} else {
494 		Flag(FSTDIN) = 1;
495 		s = pushs(SSTDIN, ATEMP);
496 		s->file = "<stdin>";
497 		s->u.shf = shf_fdopen(0, SHF_RD | can_seek(0),
498 		    NULL);
499 		if (isatty(0) && isatty(2)) {
500 			Flag(FTALKING) = Flag(FTALKING_I) = 1;
501 			/* The following only if isatty(0) */
502 			s->flags |= SF_TTY;
503 			s->u.shf->flags |= SHF_INTERRUPT;
504 			s->file = NULL;
505 		}
506 	}
507 
508 	/* this bizarreness is mandated by POSIX */
509 	if (fstat(0, &s_stdin) >= 0 && S_ISCHR(s_stdin.st_mode) &&
510 	    Flag(FTALKING))
511 		reset_nonblock(0);
512 
513 	/* initialise job control */
514 	j_init();
515 	/* do this after j_init() which calls tty_init_state() */
516 	if (Flag(FTALKING)) {
517 		if (utf_flag == 2) {
518 #ifndef MKSH_ASSUME_UTF8
519 			/* auto-detect from locale or environment */
520 			utf_flag = 4;
521 #else /* this may not be an #elif */
522 #if MKSH_ASSUME_UTF8
523 			utf_flag = 1;
524 #else
525 			/* always disable UTF-8 (for interactive) */
526 			utf_flag = 0;
527 #endif
528 #endif
529 		}
530 #ifndef MKSH_NO_CMDLINE_EDITING
531 		x_init();
532 #endif
533 	}
534 
535 #ifdef SIGWINCH
536 	sigtraps[SIGWINCH].flags |= TF_SHELL_USES;
537 	setsig(&sigtraps[SIGWINCH], x_sigwinch,
538 	    SS_RESTORE_ORIG|SS_FORCE|SS_SHTRAP);
539 #endif
540 
541 	l = e->loc;
542 	if (Flag(FAS_BUILTIN)) {
543 		l->argc = argc;
544 		l->argv = argv;
545 		l->argv[0] = ccp;
546 	} else {
547 		l->argc = argc - argi;
548 		/*
549 		 * allocate a new array because otherwise, when we modify
550 		 * it in-place, ps(1) output changes; the meaning of argc
551 		 * here is slightly different as it excludes kshname, and
552 		 * we add a trailing NULL sentinel as well
553 		 */
554 		l->argv = alloc2(l->argc + 2, sizeof(void *), APERM);
555 		l->argv[0] = kshname;
556 		memcpy(&l->argv[1], &argv[argi], l->argc * sizeof(void *));
557 		l->argv[l->argc + 1] = NULL;
558 		getopts_reset(1);
559 	}
560 
561 	/* divine the initial state of the utf8-mode Flag */
562 	ccp = null;
563 	switch (utf_flag) {
564 
565 	/* auto-detect from locale or environment */
566 	case 4:
567 #if HAVE_SETLOCALE_CTYPE
568 		ccp = setlocale(LC_CTYPE, "");
569 #if HAVE_LANGINFO_CODESET
570 		if (!isuc(ccp))
571 			ccp = nl_langinfo(CODESET);
572 #endif
573 		if (!isuc(ccp))
574 			ccp = null;
575 #endif
576 		/* FALLTHROUGH */
577 
578 	/* auto-detect from environment */
579 	case 3:
580 		/* these were imported from environ earlier */
581 		if (ccp == null)
582 			ccp = str_val(global("LC_ALL"));
583 		if (ccp == null)
584 			ccp = str_val(global("LC_CTYPE"));
585 		if (ccp == null)
586 			ccp = str_val(global("LANG"));
587 		UTFMODE = isuc(ccp);
588 		break;
589 
590 	/* not set on command line, not FTALKING */
591 	case 2:
592 	/* unknown values */
593 	default:
594 		utf_flag = 0;
595 		/* FALLTHROUGH */
596 
597 	/* known values */
598 	case 1:
599 	case 0:
600 		UTFMODE = utf_flag;
601 		break;
602 	}
603 
604 	/* Disable during .profile/ENV reading */
605 	restricted_shell = Flag(FRESTRICTED);
606 	Flag(FRESTRICTED) = 0;
607 	errexit = Flag(FERREXIT);
608 	Flag(FERREXIT) = 0;
609 
610 	/*
611 	 * Do this before profile/$ENV so that if it causes problems in them,
612 	 * user will know why things broke.
613 	 */
614 	if (!current_wd[0] && Flag(FTALKING))
615 		warningf(false, "can't determine current directory");
616 
617 	if (Flag(FLOGIN))
618 		include(MKSH_SYSTEM_PROFILE, 0, NULL, true);
619 	if (!Flag(FPRIVILEGED)) {
620 		if (Flag(FLOGIN))
621 			include(substitute("$HOME/.profile", 0), 0, NULL, true);
622 		if (Flag(FTALKING)) {
623 			cp = substitute(substitute("${ENV:-" MKSHRC_PATH "}",
624 			    0), DOTILDE);
625 			if (cp[0] != '\0')
626 				include(cp, 0, NULL, true);
627 		}
628 	} else {
629 		include(MKSH_SUID_PROFILE, 0, NULL, true);
630 		/* turn off -p if not set explicitly */
631 		if (Flag(FPRIVILEGED) != 1)
632 			change_flag(FPRIVILEGED, OF_INTERNAL, false);
633 	}
634 
635 	if (restricted_shell) {
636 		shcomexec(restr_com);
637 		/* After typeset command... */
638 		Flag(FRESTRICTED) = 1;
639 	}
640 	Flag(FERREXIT) = errexit;
641 
642 	if (Flag(FTALKING) && s)
643 		hist_init(s);
644 	else
645 		/* set after ENV */
646 		Flag(FTRACKALL) = 1;
647 
648 	alarm_init();
649 
650 	*sp = s;
651 	*lp = l;
652 	return (0);
653 }
654 
655 /* this indirection barrier reduces stack usage during normal operation */
656 
657 int
main(int argc,const char * argv[])658 main(int argc, const char *argv[])
659 {
660 	int rv;
661 	Source *s;
662 	struct block *l;
663 
664 	if ((rv = main_init(argc, argv, &s, &l)) == 0) {
665 		if (Flag(FAS_BUILTIN)) {
666 			rv = shcomexec(l->argv);
667 		} else {
668 			shell(s, true);
669 			/* NOTREACHED */
670 		}
671 	}
672 	return (rv);
673 }
674 
675 int
include(const char * name,int argc,const char ** argv,bool intr_ok)676 include(const char *name, int argc, const char **argv, bool intr_ok)
677 {
678 	Source *volatile s = NULL;
679 	struct shf *shf;
680 	const char **volatile old_argv;
681 	volatile int old_argc;
682 	int i;
683 
684 	shf = shf_open(name, O_RDONLY, 0, SHF_MAPHI | SHF_CLEXEC);
685 	if (shf == NULL)
686 		return (-1);
687 
688 	if (argv) {
689 		old_argv = e->loc->argv;
690 		old_argc = e->loc->argc;
691 	} else {
692 		old_argv = NULL;
693 		old_argc = 0;
694 	}
695 	newenv(E_INCL);
696 	if ((i = kshsetjmp(e->jbuf))) {
697 		quitenv(s ? s->u.shf : NULL);
698 		if (old_argv) {
699 			e->loc->argv = old_argv;
700 			e->loc->argc = old_argc;
701 		}
702 		switch (i) {
703 		case LRETURN:
704 		case LERROR:
705 			/* see below */
706 			return (exstat & 0xFF);
707 		case LINTR:
708 			/*
709 			 * intr_ok is set if we are including .profile or $ENV.
710 			 * If user ^Cs out, we don't want to kill the shell...
711 			 */
712 			if (intr_ok && ((exstat & 0xFF) - 128) != SIGTERM)
713 				return (1);
714 			/* FALLTHROUGH */
715 		case LEXIT:
716 		case LLEAVE:
717 		case LSHELL:
718 			unwind(i);
719 			/* NOTREACHED */
720 		default:
721 			internal_errorf("include %d", i);
722 			/* NOTREACHED */
723 		}
724 	}
725 	if (argv) {
726 		e->loc->argv = argv;
727 		e->loc->argc = argc;
728 	}
729 	s = pushs(SFILE, ATEMP);
730 	s->u.shf = shf;
731 	strdupx(s->file, name, ATEMP);
732 	i = shell(s, false);
733 	quitenv(s->u.shf);
734 	if (old_argv) {
735 		e->loc->argv = old_argv;
736 		e->loc->argc = old_argc;
737 	}
738 	/* & 0xff to ensure value not -1 */
739 	return (i & 0xFF);
740 }
741 
742 /* spawn a command into a shell optionally keeping track of the line number */
743 int
command(const char * comm,int line)744 command(const char *comm, int line)
745 {
746 	Source *s, *sold = source;
747 	int rv;
748 
749 	s = pushs(SSTRING, ATEMP);
750 	s->start = s->str = comm;
751 	s->line = line;
752 	rv = shell(s, false);
753 	source = sold;
754 	return (rv);
755 }
756 
757 /*
758  * run the commands from the input source, returning status.
759  */
760 int
shell(Source * volatile s,volatile bool toplevel)761 shell(Source * volatile s, volatile bool toplevel)
762 {
763 	struct op *t;
764 	volatile bool wastty = tobool(s->flags & SF_TTY);
765 	volatile uint8_t attempts = 13;
766 	volatile bool interactive = Flag(FTALKING) && toplevel;
767 	volatile bool sfirst = true;
768 	Source *volatile old_source = source;
769 	int i;
770 
771 	newenv(E_PARSE);
772 	if (interactive)
773 		really_exit = false;
774 	switch ((i = kshsetjmp(e->jbuf))) {
775 	case 0:
776 		break;
777 	case LINTR:
778 		/* we get here if SIGINT not caught or ignored */
779 	case LERROR:
780 	case LSHELL:
781 		if (interactive) {
782 			if (i == LINTR)
783 				shellf("\n");
784 			/*
785 			 * Reset any eof that was read as part of a
786 			 * multiline command.
787 			 */
788 			if (Flag(FIGNOREEOF) && s->type == SEOF && wastty)
789 				s->type = SSTDIN;
790 			/*
791 			 * Used by exit command to get back to
792 			 * top level shell. Kind of strange since
793 			 * interactive is set if we are reading from
794 			 * a tty, but to have stopped jobs, one only
795 			 * needs FMONITOR set (not FTALKING/SF_TTY)...
796 			 */
797 			/* toss any input we have so far */
798 			yyrecursive_pop(true);
799 			s->start = s->str = null;
800 			retrace_info = NULL;
801 			herep = heres;
802 			break;
803 		}
804 		/* FALLTHROUGH */
805 	case LEXIT:
806 	case LLEAVE:
807 	case LRETURN:
808 		source = old_source;
809 		quitenv(NULL);
810 		/* keep on going */
811 		unwind(i);
812 		/* NOTREACHED */
813 	default:
814 		source = old_source;
815 		quitenv(NULL);
816 		internal_errorf("shell %d", i);
817 		/* NOTREACHED */
818 	}
819 	while (/* CONSTCOND */ 1) {
820 		if (trap)
821 			runtraps(0);
822 
823 		if (s->next == NULL) {
824 			if (Flag(FVERBOSE))
825 				s->flags |= SF_ECHO;
826 			else
827 				s->flags &= ~SF_ECHO;
828 		}
829 		if (interactive) {
830 			j_notify();
831 			set_prompt(PS1, s);
832 		}
833 		t = compile(s, sfirst);
834 		if (interactive)
835 			histsave(&s->line, NULL, HIST_FLUSH, true);
836 		sfirst = false;
837 		if (!t)
838 			goto source_no_tree;
839 		if (t->type == TEOF) {
840 			if (wastty && Flag(FIGNOREEOF) && --attempts > 0) {
841 				shellf("Use 'exit' to leave mksh\n");
842 				s->type = SSTDIN;
843 			} else if (wastty && !really_exit &&
844 			    j_stopped_running()) {
845 				really_exit = true;
846 				s->type = SSTDIN;
847 			} else {
848 				/*
849 				 * this for POSIX which says EXIT traps
850 				 * shall be taken in the environment
851 				 * immediately after the last command
852 				 * executed.
853 				 */
854 				if (toplevel)
855 					unwind(LEXIT);
856 				break;
857 			}
858 		} else if ((s->flags & SF_MAYEXEC) && t->type == TCOM)
859 			t->u.evalflags |= DOTCOMEXEC;
860 		if (!Flag(FNOEXEC) || (s->flags & SF_TTY))
861 			exstat = execute(t, 0, NULL) & 0xFF;
862 
863 		if (t->type != TEOF && interactive && really_exit)
864 			really_exit = false;
865 
866  source_no_tree:
867 		reclaim();
868 	}
869 	quitenv(NULL);
870 	source = old_source;
871 	return (exstat & 0xFF);
872 }
873 
874 /* return to closest error handler or shell(), exit if none found */
875 /* note: i MUST NOT be 0 */
876 void
unwind(int i)877 unwind(int i)
878 {
879 	/*
880 	 * This is a kludge. We need to restore everything that was
881 	 * changed in the new environment, see cid 1005090337C7A669439
882 	 * and 10050903386452ACBF1, but fail to even save things most of
883 	 * the time. funcs.c:c_eval() changes FERREXIT temporarily to 0,
884 	 * which needs to be restored thus (related to Debian #696823).
885 	 * We did not save the shell flags, so we use a special or'd
886 	 * value here... this is mostly to clean up behind *other*
887 	 * callers of unwind(LERROR) here; exec.c has the regular case.
888 	 */
889 	if (Flag(FERREXIT) & 0x80) {
890 		/* GNU bash does not run this trapsig */
891 		trapsig(ksh_SIGERR);
892 		Flag(FERREXIT) &= ~0x80;
893 	}
894 
895 	/* ordering for EXIT vs ERR is a bit odd (this is what AT&T ksh does) */
896 	if (i == LEXIT || ((i == LERROR || i == LINTR) &&
897 	    sigtraps[ksh_SIGEXIT].trap &&
898 	    (!Flag(FTALKING) || Flag(FERREXIT)))) {
899 		++trap_nested;
900 		runtrap(&sigtraps[ksh_SIGEXIT], trap_nested == 1);
901 		--trap_nested;
902 		i = LLEAVE;
903 	} else if (Flag(FERREXIT) == 1 && (i == LERROR || i == LINTR)) {
904 		++trap_nested;
905 		runtrap(&sigtraps[ksh_SIGERR], trap_nested == 1);
906 		--trap_nested;
907 		i = LLEAVE;
908 	}
909 
910 	while (/* CONSTCOND */ 1) {
911 		switch (e->type) {
912 		case E_PARSE:
913 		case E_FUNC:
914 		case E_INCL:
915 		case E_LOOP:
916 		case E_ERRH:
917 			kshlongjmp(e->jbuf, i);
918 			/* NOTREACHED */
919 		case E_NONE:
920 			if (i == LINTR)
921 				e->flags |= EF_FAKE_SIGDIE;
922 			/* FALLTHROUGH */
923 		default:
924 			quitenv(NULL);
925 		}
926 	}
927 }
928 
929 void
newenv(int type)930 newenv(int type)
931 {
932 	struct env *ep;
933 	char *cp;
934 
935 	/*
936 	 * struct env includes ALLOC_ITEM for alignment constraints
937 	 * so first get the actually used memory, then assign it
938 	 */
939 	cp = alloc(sizeof(struct env) - sizeof(ALLOC_ITEM), ATEMP);
940 	/* undo what alloc() did to the malloc result address */
941 	ep = (void *)(cp - sizeof(ALLOC_ITEM));
942 	/* initialise public members of struct env (not the ALLOC_ITEM) */
943 	ainit(&ep->area);
944 	ep->oenv = e;
945 	ep->loc = e->loc;
946 	ep->savefd = NULL;
947 	ep->temps = NULL;
948 	ep->yyrecursive_statep = NULL;
949 	ep->type = type;
950 	ep->flags = 0;
951 	/* jump buffer is invalid because flags == 0 */
952 	e = ep;
953 }
954 
955 void
quitenv(struct shf * shf)956 quitenv(struct shf *shf)
957 {
958 	struct env *ep = e;
959 	char *cp;
960 	int fd;
961 
962 	yyrecursive_pop(true);
963 	while (ep->oenv && ep->oenv->loc != ep->loc)
964 		popblock();
965 	if (ep->savefd != NULL) {
966 		for (fd = 0; fd < NUFILE; fd++)
967 			/* if ep->savefd[fd] < 0, means fd was closed */
968 			if (ep->savefd[fd])
969 				restfd(fd, ep->savefd[fd]);
970 		if (ep->savefd[2])
971 			/* Clear any write errors */
972 			shf_reopen(2, SHF_WR, shl_out);
973 	}
974 	/*
975 	 * Bottom of the stack.
976 	 * Either main shell is exiting or cleanup_parents_env() was called.
977 	 */
978 	if (ep->oenv == NULL) {
979 #ifdef DEBUG_LEAKS
980 		int i;
981 #endif
982 
983 		if (ep->type == E_NONE) {
984 			/* Main shell exiting? */
985 #if HAVE_PERSISTENT_HISTORY
986 			if (Flag(FTALKING))
987 				hist_finish();
988 #endif
989 			j_exit();
990 			if (ep->flags & EF_FAKE_SIGDIE) {
991 				int sig = (exstat & 0xFF) - 128;
992 
993 				/*
994 				 * ham up our death a bit (AT&T ksh
995 				 * only seems to do this for SIGTERM)
996 				 * Don't do it for SIGQUIT, since we'd
997 				 * dump a core..
998 				 */
999 				if ((sig == SIGINT || sig == SIGTERM) &&
1000 				    (kshpgrp == kshpid)) {
1001 					setsig(&sigtraps[sig], SIG_DFL,
1002 					    SS_RESTORE_CURR | SS_FORCE);
1003 					kill(0, sig);
1004 				}
1005 			}
1006 		}
1007 		if (shf)
1008 			shf_close(shf);
1009 		reclaim();
1010 #ifdef DEBUG_LEAKS
1011 #ifndef MKSH_NO_CMDLINE_EDITING
1012 		x_done();
1013 #endif
1014 #ifndef MKSH_NOPROSPECTOFWORK
1015 		/* block at least SIGCHLD during/after afreeall */
1016 		sigprocmask(SIG_BLOCK, &sm_sigchld, NULL);
1017 #endif
1018 		afreeall(APERM);
1019 		for (fd = 3; fd < NUFILE; fd++)
1020 			if ((i = fcntl(fd, F_GETFD, 0)) != -1 &&
1021 			    (i & FD_CLOEXEC))
1022 				close(fd);
1023 		close(2);
1024 		close(1);
1025 		close(0);
1026 #endif
1027 		exit(exstat & 0xFF);
1028 	}
1029 	if (shf)
1030 		shf_close(shf);
1031 	reclaim();
1032 
1033 	e = e->oenv;
1034 
1035 	/* free the struct env - tricky due to the ALLOC_ITEM inside */
1036 	cp = (void *)ep;
1037 	afree(cp + sizeof(ALLOC_ITEM), ATEMP);
1038 }
1039 
1040 /* Called after a fork to cleanup stuff left over from parents environment */
1041 void
cleanup_parents_env(void)1042 cleanup_parents_env(void)
1043 {
1044 	struct env *ep;
1045 	int fd;
1046 
1047 	/*
1048 	 * Don't clean up temporary files - parent will probably need them.
1049 	 * Also, can't easily reclaim memory since variables, etc. could be
1050 	 * anywhere.
1051 	 */
1052 
1053 	/* close all file descriptors hiding in savefd */
1054 	for (ep = e; ep; ep = ep->oenv) {
1055 		if (ep->savefd) {
1056 			for (fd = 0; fd < NUFILE; fd++)
1057 				if (ep->savefd[fd] > 0)
1058 					close(ep->savefd[fd]);
1059 			afree(ep->savefd, &ep->area);
1060 			ep->savefd = NULL;
1061 		}
1062 #ifdef DEBUG_LEAKS
1063 		if (ep->type != E_NONE)
1064 			ep->type = E_GONE;
1065 #endif
1066 	}
1067 #ifndef DEBUG_LEAKS
1068 	e->oenv = NULL;
1069 #endif
1070 }
1071 
1072 /* Called just before an execve cleanup stuff temporary files */
1073 void
cleanup_proc_env(void)1074 cleanup_proc_env(void)
1075 {
1076 	struct env *ep;
1077 
1078 	for (ep = e; ep; ep = ep->oenv)
1079 		remove_temps(ep->temps);
1080 }
1081 
1082 /* remove temp files and free ATEMP Area */
1083 static void
reclaim(void)1084 reclaim(void)
1085 {
1086 	struct block *l;
1087 
1088 	while ((l = e->loc) && (!e->oenv || e->oenv->loc != l)) {
1089 		e->loc = l->next;
1090 		afreeall(&l->area);
1091 	}
1092 
1093 	remove_temps(e->temps);
1094 	e->temps = NULL;
1095 
1096 	/*
1097 	 * if the memory backing source is reclaimed, things
1098 	 * will end up badly when a function expecting it to
1099 	 * be valid is run; a NULL pointer is easily debugged
1100 	 */
1101 	if (source && source->areap == &e->area)
1102 		source = NULL;
1103 	afreeall(&e->area);
1104 }
1105 
1106 static void
remove_temps(struct temp * tp)1107 remove_temps(struct temp *tp)
1108 {
1109 	while (tp) {
1110 		if (tp->pid == procpid)
1111 			unlink(tp->tffn);
1112 		tp = tp->next;
1113 	}
1114 }
1115 
1116 /*
1117  * Initialise tty_fd. Used for tracking the size of the terminal,
1118  * saving/resetting tty modes upon forground job completion, and
1119  * for setting up the tty process group. Return values:
1120  *	0 = got controlling tty
1121  *	1 = got terminal but no controlling tty
1122  *	2 = cannot find a terminal
1123  *	3 = cannot dup fd
1124  *	4 = cannot make fd close-on-exec
1125  * An existing tty_fd is cached if no "better" one could be found,
1126  * i.e. if tty_devtty was already set or the new would not set it.
1127  */
1128 int
tty_init_fd(void)1129 tty_init_fd(void)
1130 {
1131 	int fd, rv, eno = 0;
1132 	bool do_close = false, is_devtty = true;
1133 
1134 	if (tty_devtty) {
1135 		/* already got a tty which is /dev/tty */
1136 		return (0);
1137 	}
1138 
1139 #ifdef _UWIN
1140 	/*XXX imake style */
1141 	if (isatty(3)) {
1142 		/* fd 3 on UWIN _is_ /dev/tty (or our controlling tty) */
1143 		fd = 3;
1144 		goto got_fd;
1145 	}
1146 #endif
1147 	if ((fd = open(T_devtty, O_RDWR, 0)) >= 0) {
1148 		do_close = true;
1149 		goto got_fd;
1150 	}
1151 	eno = errno;
1152 
1153 	if (tty_fd >= 0) {
1154 		/* already got a non-devtty one */
1155 		rv = 1;
1156 		goto out;
1157 	}
1158 	is_devtty = false;
1159 
1160 	if (isatty((fd = 0)) || isatty((fd = 2)))
1161 		goto got_fd;
1162 	/* cannot find one */
1163 	rv = 2;
1164 	/* assert: do_close == false */
1165 	goto out;
1166 
1167  got_fd:
1168 	if ((rv = fcntl(fd, F_DUPFD, FDBASE)) < 0) {
1169 		eno = errno;
1170 		rv = 3;
1171 		goto out;
1172 	}
1173 	if (fcntl(rv, F_SETFD, FD_CLOEXEC) < 0) {
1174 		eno = errno;
1175 		close(rv);
1176 		rv = 4;
1177 		goto out;
1178 	}
1179 	tty_fd = rv;
1180 	tty_devtty = is_devtty;
1181 	rv = eno = 0;
1182  out:
1183 	if (do_close)
1184 		close(fd);
1185 	errno = eno;
1186 	return (rv);
1187 }
1188 
1189 /* A shell error occurred (eg, syntax error, etc.) */
1190 
1191 #define VWARNINGF_ERRORPREFIX	1
1192 #define VWARNINGF_FILELINE	2
1193 #define VWARNINGF_BUILTIN	4
1194 #define VWARNINGF_INTERNAL	8
1195 
1196 static void vwarningf(unsigned int, const char *, va_list)
1197     MKSH_A_FORMAT(__printf__, 2, 0);
1198 
1199 static void
vwarningf(unsigned int flags,const char * fmt,va_list ap)1200 vwarningf(unsigned int flags, const char *fmt, va_list ap)
1201 {
1202 	if (fmt) {
1203 		if (flags & VWARNINGF_INTERNAL)
1204 			shf_fprintf(shl_out, Tf_sD_, "internal error");
1205 		if (flags & VWARNINGF_ERRORPREFIX)
1206 			error_prefix(tobool(flags & VWARNINGF_FILELINE));
1207 		if ((flags & VWARNINGF_BUILTIN) &&
1208 		    /* not set when main() calls parse_args() */
1209 		    builtin_argv0 && builtin_argv0 != kshname)
1210 			shf_fprintf(shl_out, Tf_sD_, builtin_argv0);
1211 		shf_vfprintf(shl_out, fmt, ap);
1212 		shf_putchar('\n', shl_out);
1213 	}
1214 	shf_flush(shl_out);
1215 }
1216 
1217 void
errorfx(int rc,const char * fmt,...)1218 errorfx(int rc, const char *fmt, ...)
1219 {
1220 	va_list va;
1221 
1222 	exstat = rc;
1223 
1224 	/* debugging: note that stdout not valid */
1225 	shl_stdout_ok = false;
1226 
1227 	va_start(va, fmt);
1228 	vwarningf(VWARNINGF_ERRORPREFIX | VWARNINGF_FILELINE, fmt, va);
1229 	va_end(va);
1230 	unwind(LERROR);
1231 }
1232 
1233 void
errorf(const char * fmt,...)1234 errorf(const char *fmt, ...)
1235 {
1236 	va_list va;
1237 
1238 	exstat = 1;
1239 
1240 	/* debugging: note that stdout not valid */
1241 	shl_stdout_ok = false;
1242 
1243 	va_start(va, fmt);
1244 	vwarningf(VWARNINGF_ERRORPREFIX | VWARNINGF_FILELINE, fmt, va);
1245 	va_end(va);
1246 	unwind(LERROR);
1247 }
1248 
1249 /* like errorf(), but no unwind is done */
1250 void
warningf(bool fileline,const char * fmt,...)1251 warningf(bool fileline, const char *fmt, ...)
1252 {
1253 	va_list va;
1254 
1255 	va_start(va, fmt);
1256 	vwarningf(VWARNINGF_ERRORPREFIX | (fileline ? VWARNINGF_FILELINE : 0),
1257 	    fmt, va);
1258 	va_end(va);
1259 }
1260 
1261 /*
1262  * Used by built-in utilities to prefix shell and utility name to message
1263  * (also unwinds environments for special builtins).
1264  */
1265 void
bi_errorf(const char * fmt,...)1266 bi_errorf(const char *fmt, ...)
1267 {
1268 	va_list va;
1269 
1270 	/* debugging: note that stdout not valid */
1271 	shl_stdout_ok = false;
1272 
1273 	exstat = 1;
1274 
1275 	va_start(va, fmt);
1276 	vwarningf(VWARNINGF_ERRORPREFIX | VWARNINGF_FILELINE |
1277 	    VWARNINGF_BUILTIN, fmt, va);
1278 	va_end(va);
1279 
1280 	/*
1281 	 * POSIX special builtins and ksh special builtins cause
1282 	 * non-interactive shells to exit. XXX may not want LERROR here
1283 	 */
1284 	if (builtin_spec) {
1285 		builtin_argv0 = NULL;
1286 		unwind(LERROR);
1287 	}
1288 }
1289 
1290 /* Called when something that shouldn't happen does */
1291 void
internal_errorf(const char * fmt,...)1292 internal_errorf(const char *fmt, ...)
1293 {
1294 	va_list va;
1295 
1296 	va_start(va, fmt);
1297 	vwarningf(VWARNINGF_INTERNAL, fmt, va);
1298 	va_end(va);
1299 	unwind(LERROR);
1300 }
1301 
1302 void
internal_warningf(const char * fmt,...)1303 internal_warningf(const char *fmt, ...)
1304 {
1305 	va_list va;
1306 
1307 	va_start(va, fmt);
1308 	vwarningf(VWARNINGF_INTERNAL, fmt, va);
1309 	va_end(va);
1310 }
1311 
1312 /* used by error reporting functions to print "ksh: .kshrc[25]: " */
1313 void
error_prefix(bool fileline)1314 error_prefix(bool fileline)
1315 {
1316 	/* Avoid foo: foo[2]: ... */
1317 	if (!fileline || !source || !source->file ||
1318 	    strcmp(source->file, kshname) != 0)
1319 		shf_fprintf(shl_out, Tf_sD_, kshname + (*kshname == '-'));
1320 	if (fileline && source && source->file != NULL) {
1321 		shf_fprintf(shl_out, "%s[%lu]: ", source->file,
1322 		    (unsigned long)(source->errline ?
1323 		    source->errline : source->line));
1324 		source->errline = 0;
1325 	}
1326 }
1327 
1328 /* printf to shl_out (stderr) with flush */
1329 void
shellf(const char * fmt,...)1330 shellf(const char *fmt, ...)
1331 {
1332 	va_list va;
1333 
1334 	if (!initio_done)
1335 		/* shl_out may not be set up yet... */
1336 		return;
1337 	va_start(va, fmt);
1338 	shf_vfprintf(shl_out, fmt, va);
1339 	va_end(va);
1340 	shf_flush(shl_out);
1341 }
1342 
1343 /* printf to shl_stdout (stdout) */
1344 void
shprintf(const char * fmt,...)1345 shprintf(const char *fmt, ...)
1346 {
1347 	va_list va;
1348 
1349 	if (!shl_stdout_ok)
1350 		internal_errorf("shl_stdout not valid");
1351 	va_start(va, fmt);
1352 	shf_vfprintf(shl_stdout, fmt, va);
1353 	va_end(va);
1354 }
1355 
1356 /* test if we can seek backwards fd (returns 0 or SHF_UNBUF) */
1357 int
can_seek(int fd)1358 can_seek(int fd)
1359 {
1360 	struct stat statb;
1361 
1362 	return (fstat(fd, &statb) == 0 && !S_ISREG(statb.st_mode) ?
1363 	    SHF_UNBUF : 0);
1364 }
1365 
1366 #ifdef DF
1367 int shl_dbg_fd;
1368 #define NSHF_IOB 4
1369 #else
1370 #define NSHF_IOB 3
1371 #endif
1372 struct shf shf_iob[NSHF_IOB];
1373 
1374 void
initio(void)1375 initio(void)
1376 {
1377 #ifdef DF
1378 	const char *lfp;
1379 #endif
1380 
1381 	/* force buffer allocation */
1382 	shf_fdopen(1, SHF_WR, shl_stdout);
1383 	shf_fdopen(2, SHF_WR, shl_out);
1384 	shf_fdopen(2, SHF_WR, shl_xtrace);
1385 #ifdef DF
1386 	if ((lfp = getenv("SDMKSH_PATH")) == NULL) {
1387 		if ((lfp = getenv("HOME")) == NULL || !mksh_abspath(lfp))
1388 			errorf("cannot get home directory");
1389 		lfp = shf_smprintf(Tf_sSs, lfp, "mksh-dbg.txt");
1390 	}
1391 
1392 	if ((shl_dbg_fd = open(lfp, O_WRONLY | O_APPEND | O_CREAT, 0600)) < 0)
1393 		errorf("cannot open debug output file %s", lfp);
1394 	if (shl_dbg_fd < FDBASE) {
1395 		int nfd;
1396 
1397 		nfd = fcntl(shl_dbg_fd, F_DUPFD, FDBASE);
1398 		close(shl_dbg_fd);
1399 		if ((shl_dbg_fd = nfd) == -1)
1400 			errorf("cannot dup debug output file");
1401 	}
1402 	fcntl(shl_dbg_fd, F_SETFD, FD_CLOEXEC);
1403 	shf_fdopen(shl_dbg_fd, SHF_WR, shl_dbg);
1404 	DF("=== open ===");
1405 #endif
1406 	initio_done = true;
1407 }
1408 
1409 /* A dup2() with error checking */
1410 int
ksh_dup2(int ofd,int nfd,bool errok)1411 ksh_dup2(int ofd, int nfd, bool errok)
1412 {
1413 	int rv;
1414 
1415 	if (((rv = dup2(ofd, nfd)) < 0) && !errok && (errno != EBADF))
1416 		errorf("too many files open in shell");
1417 
1418 #ifdef __ultrix
1419 	/*XXX imake style */
1420 	if (rv >= 0)
1421 		fcntl(nfd, F_SETFD, 0);
1422 #endif
1423 
1424 	return (rv);
1425 }
1426 
1427 /*
1428  * Move fd from user space (0 <= fd < 10) to shell space (fd >= 10),
1429  * set close-on-exec flag. See FDBASE in sh.h, maybe 24 not 10 here.
1430  */
1431 short
savefd(int fd)1432 savefd(int fd)
1433 {
1434 	int nfd = fd;
1435 
1436 	if (fd < FDBASE && (nfd = fcntl(fd, F_DUPFD, FDBASE)) < 0 &&
1437 	    (errno == EBADF || errno == EPERM))
1438 		return (-1);
1439 	if (nfd < 0 || nfd > SHRT_MAX)
1440 		errorf("too many files open in shell");
1441 	fcntl(nfd, F_SETFD, FD_CLOEXEC);
1442 	return ((short)nfd);
1443 }
1444 
1445 void
restfd(int fd,int ofd)1446 restfd(int fd, int ofd)
1447 {
1448 	if (fd == 2)
1449 		shf_flush(&shf_iob[/* fd */ 2]);
1450 	if (ofd < 0)
1451 		/* original fd closed */
1452 		close(fd);
1453 	else if (fd != ofd) {
1454 		/*XXX: what to do if this dup fails? */
1455 		ksh_dup2(ofd, fd, true);
1456 		close(ofd);
1457 	}
1458 }
1459 
1460 void
openpipe(int * pv)1461 openpipe(int *pv)
1462 {
1463 	int lpv[2];
1464 
1465 	if (pipe(lpv) < 0)
1466 		errorf("can't create pipe - try again");
1467 	pv[0] = savefd(lpv[0]);
1468 	if (pv[0] != lpv[0])
1469 		close(lpv[0]);
1470 	pv[1] = savefd(lpv[1]);
1471 	if (pv[1] != lpv[1])
1472 		close(lpv[1]);
1473 }
1474 
1475 void
closepipe(int * pv)1476 closepipe(int *pv)
1477 {
1478 	close(pv[0]);
1479 	close(pv[1]);
1480 }
1481 
1482 /*
1483  * Called by iosetup() (deals with 2>&4, etc.), c_read, c_print to turn
1484  * a string (the X in 2>&X, read -uX, print -uX) into a file descriptor.
1485  */
1486 int
check_fd(const char * name,int mode,const char ** emsgp)1487 check_fd(const char *name, int mode, const char **emsgp)
1488 {
1489 	int fd, fl;
1490 
1491 	if (!name[0] || name[1])
1492 		goto illegal_fd_name;
1493 	if (name[0] == 'p')
1494 		return (coproc_getfd(mode, emsgp));
1495 	if (!ksh_isdigit(name[0])) {
1496  illegal_fd_name:
1497 		if (emsgp)
1498 			*emsgp = "illegal file descriptor name";
1499 		return (-1);
1500 	}
1501 
1502 	if ((fl = fcntl((fd = ksh_numdig(name[0])), F_GETFL, 0)) < 0) {
1503 		if (emsgp)
1504 			*emsgp = "bad file descriptor";
1505 		return (-1);
1506 	}
1507 	fl &= O_ACCMODE;
1508 	/*
1509 	 * X_OK is a kludge to disable this check for dups (x<&1):
1510 	 * historical shells never did this check (XXX don't know what
1511 	 * POSIX has to say).
1512 	 */
1513 	if (!(mode & X_OK) && fl != O_RDWR && (
1514 	    ((mode & R_OK) && fl != O_RDONLY) ||
1515 	    ((mode & W_OK) && fl != O_WRONLY))) {
1516 		if (emsgp)
1517 			*emsgp = (fl == O_WRONLY) ?
1518 			    "fd not open for reading" :
1519 			    "fd not open for writing";
1520 		return (-1);
1521 	}
1522 	return (fd);
1523 }
1524 
1525 /* Called once from main */
1526 void
coproc_init(void)1527 coproc_init(void)
1528 {
1529 	coproc.read = coproc.readw = coproc.write = -1;
1530 	coproc.njobs = 0;
1531 	coproc.id = 0;
1532 }
1533 
1534 /* Called by c_read() when eof is read - close fd if it is the co-process fd */
1535 void
coproc_read_close(int fd)1536 coproc_read_close(int fd)
1537 {
1538 	if (coproc.read >= 0 && fd == coproc.read) {
1539 		coproc_readw_close(fd);
1540 		close(coproc.read);
1541 		coproc.read = -1;
1542 	}
1543 }
1544 
1545 /*
1546  * Called by c_read() and by iosetup() to close the other side of the
1547  * read pipe, so reads will actually terminate.
1548  */
1549 void
coproc_readw_close(int fd)1550 coproc_readw_close(int fd)
1551 {
1552 	if (coproc.readw >= 0 && coproc.read >= 0 && fd == coproc.read) {
1553 		close(coproc.readw);
1554 		coproc.readw = -1;
1555 	}
1556 }
1557 
1558 /*
1559  * Called by c_print when a write to a fd fails with EPIPE and by iosetup
1560  * when co-process input is dup'd
1561  */
1562 void
coproc_write_close(int fd)1563 coproc_write_close(int fd)
1564 {
1565 	if (coproc.write >= 0 && fd == coproc.write) {
1566 		close(coproc.write);
1567 		coproc.write = -1;
1568 	}
1569 }
1570 
1571 /*
1572  * Called to check for existence of/value of the co-process file descriptor.
1573  * (Used by check_fd() and by c_read/c_print to deal with -p option).
1574  */
1575 int
coproc_getfd(int mode,const char ** emsgp)1576 coproc_getfd(int mode, const char **emsgp)
1577 {
1578 	int fd = (mode & R_OK) ? coproc.read : coproc.write;
1579 
1580 	if (fd >= 0)
1581 		return (fd);
1582 	if (emsgp)
1583 		*emsgp = "no coprocess";
1584 	return (-1);
1585 }
1586 
1587 /*
1588  * called to close file descriptors related to the coprocess (if any)
1589  * Should be called with SIGCHLD blocked.
1590  */
1591 void
coproc_cleanup(int reuse)1592 coproc_cleanup(int reuse)
1593 {
1594 	/* This to allow co-processes to share output pipe */
1595 	if (!reuse || coproc.readw < 0 || coproc.read < 0) {
1596 		if (coproc.read >= 0) {
1597 			close(coproc.read);
1598 			coproc.read = -1;
1599 		}
1600 		if (coproc.readw >= 0) {
1601 			close(coproc.readw);
1602 			coproc.readw = -1;
1603 		}
1604 	}
1605 	if (coproc.write >= 0) {
1606 		close(coproc.write);
1607 		coproc.write = -1;
1608 	}
1609 }
1610 
1611 struct temp *
maketemp(Area * ap,Temp_type type,struct temp ** tlist)1612 maketemp(Area *ap, Temp_type type, struct temp **tlist)
1613 {
1614 	char *cp;
1615 	size_t len;
1616 	int i, j;
1617 	struct temp *tp;
1618 	const char *dir;
1619 	struct stat sb;
1620 
1621 	dir = tmpdir ? tmpdir : MKSH_DEFAULT_TMPDIR;
1622 	/* add "/shXXXXXX.tmp" plus NUL */
1623 	len = strlen(dir);
1624 	checkoktoadd(len, offsetof(struct temp, tffn[0]) + 14);
1625 	tp = alloc(offsetof(struct temp, tffn[0]) + 14 + len, ap);
1626 
1627 	tp->shf = NULL;
1628 	tp->pid = procpid;
1629 	tp->type = type;
1630 
1631 	if (stat(dir, &sb) || !S_ISDIR(sb.st_mode)) {
1632 		tp->tffn[0] = '\0';
1633 		goto maketemp_out;
1634 	}
1635 
1636 	cp = (void *)tp;
1637 	cp += offsetof(struct temp, tffn[0]);
1638 	memcpy(cp, dir, len);
1639 	cp += len;
1640 	memcpy(cp, "/shXXXXXX.tmp", 14);
1641 	/* point to the first of six Xes */
1642 	cp += 3;
1643 
1644 	/* cyclically attempt to open a temporary file */
1645 	do {
1646 		/* generate random part of filename */
1647 		len = 0;
1648 		do {
1649 			cp[len++] = digits_lc[rndget() % 36];
1650 		} while (len < 6);
1651 
1652 		/* check if this one works */
1653 		if ((i = binopen3(tp->tffn, O_CREAT | O_EXCL | O_RDWR,
1654 		    0600)) < 0 && errno != EEXIST)
1655 			goto maketemp_out;
1656 	} while (i < 0);
1657 
1658 	if (type == TT_FUNSUB) {
1659 		/* map us high and mark as close-on-exec */
1660 		if ((j = savefd(i)) != i) {
1661 			close(i);
1662 			i = j;
1663 		}
1664 
1665 		/* operation mode for the shf */
1666 		j = SHF_RD;
1667 	} else
1668 		j = SHF_WR;
1669 
1670 	/* shf_fdopen cannot fail, so no fd leak */
1671 	tp->shf = shf_fdopen(i, j, NULL);
1672 
1673  maketemp_out:
1674 	tp->next = *tlist;
1675 	*tlist = tp;
1676 	return (tp);
1677 }
1678 
1679 /*
1680  * We use a similar collision resolution algorithm as Python 2.5.4
1681  * but with a slightly tweaked implementation written from scratch.
1682  */
1683 
1684 #define	INIT_TBLSHIFT	3	/* initial table shift (2^3 = 8) */
1685 #define PERTURB_SHIFT	5	/* see Python 2.5.4 Objects/dictobject.c */
1686 
1687 static void tgrow(struct table *);
1688 static int tnamecmp(const void *, const void *);
1689 
1690 static void
tgrow(struct table * tp)1691 tgrow(struct table *tp)
1692 {
1693 	size_t i, j, osize, mask, perturb;
1694 	struct tbl *tblp, **pp;
1695 	struct tbl **ntblp, **otblp = tp->tbls;
1696 
1697 	if (tp->tshift > 29)
1698 		internal_errorf("hash table size limit reached");
1699 
1700 	/* calculate old size, new shift and new size */
1701 	osize = (size_t)1 << (tp->tshift++);
1702 	i = osize << 1;
1703 
1704 	ntblp = alloc2(i, sizeof(struct tbl *), tp->areap);
1705 	/* multiplication cannot overflow: alloc2 checked that */
1706 	memset(ntblp, 0, i * sizeof(struct tbl *));
1707 
1708 	/* table can get very full when reaching its size limit */
1709 	tp->nfree = (tp->tshift == 30) ? 0x3FFF0000UL :
1710 	    /* but otherwise, only 75% */
1711 	    ((i * 3) / 4);
1712 	tp->tbls = ntblp;
1713 	if (otblp == NULL)
1714 		return;
1715 
1716 	mask = i - 1;
1717 	for (i = 0; i < osize; i++)
1718 		if ((tblp = otblp[i]) != NULL) {
1719 			if ((tblp->flag & DEFINED)) {
1720 				/* search for free hash table slot */
1721 				j = perturb = tblp->ua.hval;
1722 				goto find_first_empty_slot;
1723  find_next_empty_slot:
1724 				j = (j << 2) + j + perturb + 1;
1725 				perturb >>= PERTURB_SHIFT;
1726  find_first_empty_slot:
1727 				pp = &ntblp[j & mask];
1728 				if (*pp != NULL)
1729 					goto find_next_empty_slot;
1730 				/* found an empty hash table slot */
1731 				*pp = tblp;
1732 				tp->nfree--;
1733 			} else if (!(tblp->flag & FINUSE)) {
1734 				afree(tblp, tp->areap);
1735 			}
1736 		}
1737 	afree(otblp, tp->areap);
1738 }
1739 
1740 void
ktinit(Area * ap,struct table * tp,uint8_t initshift)1741 ktinit(Area *ap, struct table *tp, uint8_t initshift)
1742 {
1743 	tp->areap = ap;
1744 	tp->tbls = NULL;
1745 	tp->tshift = ((initshift > INIT_TBLSHIFT) ?
1746 	    initshift : INIT_TBLSHIFT) - 1;
1747 	tgrow(tp);
1748 }
1749 
1750 /* table, name (key) to search for, hash(name), rv pointer to tbl ptr */
1751 struct tbl *
ktscan(struct table * tp,const char * name,uint32_t h,struct tbl *** ppp)1752 ktscan(struct table *tp, const char *name, uint32_t h, struct tbl ***ppp)
1753 {
1754 	size_t j, perturb, mask;
1755 	struct tbl **pp, *p;
1756 
1757 	mask = ((size_t)1 << (tp->tshift)) - 1;
1758 	/* search for hash table slot matching name */
1759 	j = perturb = h;
1760 	goto find_first_slot;
1761  find_next_slot:
1762 	j = (j << 2) + j + perturb + 1;
1763 	perturb >>= PERTURB_SHIFT;
1764  find_first_slot:
1765 	pp = &tp->tbls[j & mask];
1766 	if ((p = *pp) != NULL && (p->ua.hval != h || !(p->flag & DEFINED) ||
1767 	    strcmp(p->name, name)))
1768 		goto find_next_slot;
1769 	/* p == NULL if not found, correct found entry otherwise */
1770 	if (ppp)
1771 		*ppp = pp;
1772 	return (p);
1773 }
1774 
1775 /* table, name (key) to enter, hash(n) */
1776 struct tbl *
ktenter(struct table * tp,const char * n,uint32_t h)1777 ktenter(struct table *tp, const char *n, uint32_t h)
1778 {
1779 	struct tbl **pp, *p;
1780 	size_t len;
1781 
1782  Search:
1783 	if ((p = ktscan(tp, n, h, &pp)))
1784 		return (p);
1785 
1786 	if (tp->nfree == 0) {
1787 		/* too full */
1788 		tgrow(tp);
1789 		goto Search;
1790 	}
1791 
1792 	/* create new tbl entry */
1793 	len = strlen(n);
1794 	checkoktoadd(len, offsetof(struct tbl, name[0]) + 1);
1795 	p = alloc(offsetof(struct tbl, name[0]) + ++len, tp->areap);
1796 	p->flag = 0;
1797 	p->type = 0;
1798 	p->areap = tp->areap;
1799 	p->ua.hval = h;
1800 	p->u2.field = 0;
1801 	p->u.array = NULL;
1802 	memcpy(p->name, n, len);
1803 
1804 	/* enter in tp->tbls */
1805 	tp->nfree--;
1806 	*pp = p;
1807 	return (p);
1808 }
1809 
1810 void
ktwalk(struct tstate * ts,struct table * tp)1811 ktwalk(struct tstate *ts, struct table *tp)
1812 {
1813 	ts->left = (size_t)1 << (tp->tshift);
1814 	ts->next = tp->tbls;
1815 }
1816 
1817 struct tbl *
ktnext(struct tstate * ts)1818 ktnext(struct tstate *ts)
1819 {
1820 	while (--ts->left >= 0) {
1821 		struct tbl *p = *ts->next++;
1822 		if (p != NULL && (p->flag & DEFINED))
1823 			return (p);
1824 	}
1825 	return (NULL);
1826 }
1827 
1828 static int
tnamecmp(const void * p1,const void * p2)1829 tnamecmp(const void *p1, const void *p2)
1830 {
1831 	const struct tbl *a = *((const struct tbl * const *)p1);
1832 	const struct tbl *b = *((const struct tbl * const *)p2);
1833 
1834 	return (strcmp(a->name, b->name));
1835 }
1836 
1837 struct tbl **
ktsort(struct table * tp)1838 ktsort(struct table *tp)
1839 {
1840 	size_t i;
1841 	struct tbl **p, **sp, **dp;
1842 
1843 	/*
1844 	 * since the table is never entirely full, no need to reserve
1845 	 * additional space for the trailing NULL appended below
1846 	 */
1847 	i = (size_t)1 << (tp->tshift);
1848 	p = alloc2(i, sizeof(struct tbl *), ATEMP);
1849 	sp = tp->tbls;		/* source */
1850 	dp = p;			/* dest */
1851 	while (i--)
1852 		if ((*dp = *sp++) != NULL && (((*dp)->flag & DEFINED) ||
1853 		    ((*dp)->flag & ARRAY)))
1854 			dp++;
1855 	qsort(p, (i = dp - p), sizeof(struct tbl *), tnamecmp);
1856 	p[i] = NULL;
1857 	return (p);
1858 }
1859 
1860 #ifdef SIGWINCH
1861 static void
x_sigwinch(int sig MKSH_A_UNUSED)1862 x_sigwinch(int sig MKSH_A_UNUSED)
1863 {
1864 	/* this runs inside interrupt context, with errno saved */
1865 
1866 	got_winch = 1;
1867 }
1868 #endif
1869 
1870 #ifdef DF
1871 void
DF(const char * fmt,...)1872 DF(const char *fmt, ...)
1873 {
1874 	va_list args;
1875 	struct timeval tv;
1876 	mirtime_mjd mjd;
1877 
1878 	mksh_lockfd(shl_dbg_fd);
1879 	mksh_TIME(tv);
1880 	timet2mjd(&mjd, tv.tv_sec);
1881 	shf_fprintf(shl_dbg, "[%02u:%02u:%02u (%u) %u.%06u] ",
1882 	    (unsigned)mjd.sec / 3600, ((unsigned)mjd.sec / 60) % 60,
1883 	    (unsigned)mjd.sec % 60, (unsigned)getpid(),
1884 	    (unsigned)tv.tv_sec, (unsigned)tv.tv_usec);
1885 	va_start(args, fmt);
1886 	shf_vfprintf(shl_dbg, fmt, args);
1887 	va_end(args);
1888 	shf_putc('\n', shl_dbg);
1889 	shf_flush(shl_dbg);
1890 	mksh_unlkfd(shl_dbg_fd);
1891 }
1892 #endif
1893 
1894 void
x_mkraw(int fd,mksh_ttyst * ocb,bool forread)1895 x_mkraw(int fd, mksh_ttyst *ocb, bool forread)
1896 {
1897 	mksh_ttyst cb;
1898 
1899 	if (ocb)
1900 		mksh_tcget(fd, ocb);
1901 	else
1902 		ocb = &tty_state;
1903 
1904 	cb = *ocb;
1905 	if (forread) {
1906 		cb.c_iflag &= ~(ISTRIP);
1907 		cb.c_lflag &= ~(ICANON) | ECHO;
1908 	} else {
1909 		cb.c_iflag &= ~(INLCR | ICRNL | ISTRIP);
1910 		cb.c_lflag &= ~(ISIG | ICANON | ECHO);
1911 	}
1912 #if defined(VLNEXT) && defined(_POSIX_VDISABLE)
1913 	/* OSF/1 processes lnext when ~icanon */
1914 	cb.c_cc[VLNEXT] = _POSIX_VDISABLE;
1915 #endif
1916 	/* SunOS 4.1.x & OSF/1 processes discard(flush) when ~icanon */
1917 #if defined(VDISCARD) && defined(_POSIX_VDISABLE)
1918 	cb.c_cc[VDISCARD] = _POSIX_VDISABLE;
1919 #endif
1920 	cb.c_cc[VTIME] = 0;
1921 	cb.c_cc[VMIN] = 1;
1922 
1923 	mksh_tcset(fd, &cb);
1924 }
1925