text: /*	$OpenBSD: main.c,v 1.57 2015/09/10 22:48:58 nicm Exp $	*/
  /*	$OpenBSD: tty.c,v 1.10 2014/08/10 02:44:26 guenther Exp $	*/
  /*	$OpenBSD: io.c,v 1.26 2015/09/11 08:00:27 guenther Exp $	*/
  /*	$OpenBSD: table.c,v 1.16 2015/09/01 13:12:31 tedu Exp $	*/
  
  /*-
   * Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
   *		 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018,
   *		 2019
   *	mirabilos <m@mirbsd.org>
   *
   * Provided that these terms and disclaimer and all copyright notices
   * are retained or reproduced in an accompanying document, permission
   * is granted to deal in this work without restriction, including un-
   * limited rights to use, publicly perform, distribute, sell, modify,
   * merge, give away, or sublicence.
   *
   * This work is provided "AS IS" and WITHOUT WARRANTY of any kind, to
   * the utmost extent permitted by applicable law, neither express nor
   * implied; without malicious intent or gross negligence. In no event
   * may a licensor, author or contributor be held liable for indirect,
   * direct, other damage, loss, or other issues arising in any way out
   * of dealing in the work, even if advised of the possibility of such
   * damage or existence of a defect, except proven that it results out
   * of said person's immediate fault when using the work as intended.
   */
  
  #define EXTERN
  #include "sh.h"
  
  #if HAVE_LANGINFO_CODESET
  #include <langinfo.h>
  #endif
  #if HAVE_SETLOCALE_CTYPE
  #include <locale.h>
  #endif
  
  __RCSID("$MirOS: src/bin/mksh/main.c,v 1.351 2019/01/05 13:24:18 tg Exp $");
  
  #ifndef MKSHRC_PATH
  #define MKSHRC_PATH	"~/.mkshrc"
  #endif
  
  #ifndef MKSH_DEFAULT_TMPDIR
  #define MKSH_DEFAULT_TMPDIR	MKSH_UNIXROOT "/tmp"
  #endif
  
  static uint8_t isuc(const char *);
  static int main_init(int, const char *[], Source **, struct block **);
  void chvt_reinit(void);
  static void reclaim(void);
  static void remove_temps(struct temp *);
  static mksh_uari_t rndsetup(void);
  static void init_environ(void);
  #ifdef SIGWINCH
  static void x_sigwinch(int);
  #endif
  
  static const char initsubs[] =
      "${PS2=> }"
      "${PS3=#? }"
      "${PS4=+ }"
      "${SECONDS=0}"
      "${TMOUT=0}"
      "${EPOCHREALTIME=}";
  
  static const char *initcoms[] = {
  	Ttypeset, "-r", initvsn, NULL,
  	Ttypeset, "-x", "HOME", TPATH, TSHELL, NULL,
  	Ttypeset, "-i10", "COLUMNS", "LINES", "SECONDS", "TMOUT", NULL,
  	Talias,
  	"integer=\\\\builtin typeset -i",
  	"local=\\\\builtin typeset",
  	/* not "alias -t --": hash -r needs to work */
  	"hash=\\\\builtin alias -t",
  	"type=\\\\builtin whence -v",
  	"autoload=\\\\builtin typeset -fu",
  	"functions=\\\\builtin typeset -f",
  	"history=\\\\builtin fc -l",
  	"nameref=\\\\builtin typeset -n",
  	"nohup=nohup ",
  	"r=\\\\builtin fc -e -",
  	"login=\\\\builtin exec login",
  	NULL,
  	 /* this is what AT&T ksh seems to track, with the addition of emacs */
  	Talias, "-tU",
  	Tcat, "cc", "chmod", "cp", "date", "ed", "emacs", "grep", "ls",
  	"make", "mv", "pr", "rm", "sed", Tsh, "vi", "who", NULL,
  	NULL
  };
  
  static const char *restr_com[] = {
  	Ttypeset, "-r", TPATH, "ENV", TSHELL, NULL
  };
  
  static bool initio_done;
  
  /* top-level parsing and execution environment */
  static struct env env;
  struct env *e = &env;
  
  /* compile-time assertions */
  #define cta(name, expr) struct cta_ ## name { char t[(expr) ? 1 : -1]; }
  
  /* this one should be defined by the standard */
  cta(char_is_1_char, (sizeof(char) == 1) && (sizeof(signed char) == 1) &&
      (sizeof(unsigned char) == 1));
  cta(char_is_8_bits, ((CHAR_BIT) == 8) && ((int)(unsigned char)0xFF == 0xFF) &&
      ((int)(unsigned char)0x100 == 0) && ((int)(unsigned char)(int)-1 == 0xFF));
  /* the next assertion is probably not really needed */
  cta(short_is_2_char, sizeof(short) == 2);
  cta(short_size_no_matter_of_signedness, sizeof(short) == sizeof(unsigned short));
  /* the next assertion is probably not really needed */
  cta(int_is_4_char, sizeof(int) == 4);
  cta(int_size_no_matter_of_signedness, sizeof(int) == sizeof(unsigned int));
  
  cta(long_ge_int, sizeof(long) >= sizeof(int));
  cta(long_size_no_matter_of_signedness, sizeof(long) == sizeof(unsigned long));
  
  #ifndef MKSH_LEGACY_MODE
  /* the next assertion is probably not really needed */
  cta(ari_is_4_char, sizeof(mksh_ari_t) == 4);
  /* but this is */
  cta(ari_has_31_bit, 0 < (mksh_ari_t)(((((mksh_ari_t)1 << 15) << 15) - 1) * 2 + 1));
  /* the next assertion is probably not really needed */
  cta(uari_is_4_char, sizeof(mksh_uari_t) == 4);
  /* but the next three are; we REQUIRE unsigned integer wraparound */
  cta(uari_has_31_bit, 0 < (mksh_uari_t)(((((mksh_uari_t)1 << 15) << 15) - 1) * 2 + 1));
  cta(uari_has_32_bit, 0 < (mksh_uari_t)(((((mksh_uari_t)1 << 15) << 15) - 1) * 4 + 3));
  cta(uari_wrap_32_bit,
      (mksh_uari_t)(((((mksh_uari_t)1 << 15) << 15) - 1) * 4 + 3) >
      (mksh_uari_t)(((((mksh_uari_t)1 << 15) << 15) - 1) * 4 + 4));
  #endif
  /* these are always required */
  cta(ari_is_signed, (mksh_ari_t)-1 < (mksh_ari_t)0);
  cta(uari_is_unsigned, (mksh_uari_t)-1 > (mksh_uari_t)0);
  /* we require these to have the precisely same size and assume 2s complement */
  cta(ari_size_no_matter_of_signedness, sizeof(mksh_ari_t) == sizeof(mksh_uari_t));
  
  cta(sizet_size_no_matter_of_signedness, sizeof(ssize_t) == sizeof(size_t));
  cta(sizet_voidptr_same_size, sizeof(size_t) == sizeof(void *));
  cta(sizet_funcptr_same_size, sizeof(size_t) == sizeof(void (*)(void)));
  /* our formatting routines assume this */
  cta(ptr_fits_in_long, sizeof(size_t) <= sizeof(long));
  cta(ari_fits_in_long, sizeof(mksh_ari_t) <= sizeof(long));
  
  static mksh_uari_t
  rndsetup(void)
  {
  	register uint32_t h;
  	struct {
  		ALLOC_ITEM alloc_INT;
  		void *dataptr, *stkptr, *mallocptr;
  #if defined(__GLIBC__) && (__GLIBC__ >= 2)
  		sigjmp_buf jbuf;
  #endif
  		struct timeval tv;
  	} *bufptr;
  	char *cp;
  
  	cp = alloc(sizeof(*bufptr) - sizeof(ALLOC_ITEM), APERM);
  	/* clear the allocated space, for valgrind and to avoid UB */
  	memset(cp, 0, sizeof(*bufptr) - sizeof(ALLOC_ITEM));
  	/* undo what alloc() did to the malloc result address */
  	bufptr = (void *)(cp - sizeof(ALLOC_ITEM));
  	/* PIE or something similar provides us with deltas here */
  	bufptr->dataptr = &rndsetupstate;
  	/* ASLR in at least Windows, Linux, some BSDs */
  	bufptr->stkptr = &bufptr;
  	/* randomised malloc in BSD (and possibly others) */
  	bufptr->mallocptr = bufptr;
  #if defined(__GLIBC__) && (__GLIBC__ >= 2)
  	/* glibc pointer guard */
  	sigsetjmp(bufptr->jbuf, 1);
  #endif
  	/* introduce variation (and yes, second arg MBZ for portability) */
  	mksh_TIME(bufptr->tv);
  
  #ifdef MKSH_ALLOC_CATCH_UNDERRUNS
  	mprotect(((char *)bufptr) + 4096, 4096, PROT_READ | PROT_WRITE);
  #endif
  	h = chvt_rndsetup(bufptr, sizeof(*bufptr));
  
  	afree(cp, APERM);
  	return ((mksh_uari_t)h);
  }
  
  void
  chvt_reinit(void)
  {
  	kshpid = procpid = getpid();
  	ksheuid = geteuid();
  	kshpgrp = getpgrp();
  	kshppid = getppid();
  }
  
  static const char *empty_argv[] = {
  	Tmksh, NULL
  };
  
  static uint8_t
  isuc(const char *cx) {
  	char *cp, *x;
  	uint8_t rv = 0;
  
  	if (!cx || !*cx)
  		return (0);
  
  	/* uppercase a string duplicate */
  	strdupx(x, cx, ATEMP);
  	cp = x;
  	while ((*cp = ksh_toupper(*cp)))
  		++cp;
  
  	/* check for UTF-8 */
  	if (strstr(x, "UTF-8") || strstr(x, "UTF8"))
  		rv = 1;
  
  	/* free copy and out */
  	afree(x, ATEMP);
  	return (rv);
  }
  
  static int
  main_init(int argc, const char *argv[], Source **sp, struct block **lp)
  {
  	int argi, i;
  	Source *s = NULL;
  	struct block *l;
  	unsigned char restricted_shell, errexit, utf_flag;
  	char *cp;
  	const char *ccp, **wp;
  	struct tbl *vp;
  	struct stat s_stdin;
  #if !defined(_PATH_DEFPATH) && defined(_CS_PATH)
  	ssize_t k;
  #endif
  
  #if defined(MKSH_EBCDIC) || defined(MKSH_FAUX_EBCDIC)
  	ebcdic_init();
  #endif
  	set_ifs(TC_IFSWS);
  
  #ifdef __OS2__
  	os2_init(&argc, &argv);
  #endif
  
  	/* do things like getpgrp() et al. */
  	chvt_reinit();
  
  	/* make sure argv[] is sane, for weird OSes */
  	if (!*argv) {
  		argv = empty_argv;
  		argc = 1;
  	}
  	kshname = argv[0];
  
  	/* initialise permanent Area */
  	ainit(&aperm);
  	/* max. name length: -2147483648 = 11 (+ NUL) */
  	vtemp = alloc(offsetof(struct tbl, name[0]) + 12, APERM);
  
  	/* set up base environment */
  	env.type = E_NONE;
  	ainit(&env.area);
  	/* set up global l->vars and l->funs */
  	newblock();
  
  	/* Do this first so output routines (eg, errorf, shellf) can work */
  	initio();
  
  	/* determine the basename (without '-' or path) of the executable */
  	ccp = kshname;
  	goto begin_parsing_kshname;
  	while ((i = ccp[argi++])) {
  		if (mksh_cdirsep(i)) {
  			ccp += argi;
   begin_parsing_kshname:
  			argi = 0;
  			if (*ccp == '-')
  				++ccp;
  		}
  	}
  	if (!*ccp)
  		ccp = empty_argv[0];
  
  	/*
  	 * Turn on nohup by default. (AT&T ksh does not have a nohup
  	 * option - it always sends the hup).
  	 */
  	Flag(FNOHUP) = 1;
  
  	/*
  	 * Turn on brace expansion by default. AT&T kshs that have
  	 * alternation always have it on.
  	 */
  	Flag(FBRACEEXPAND) = 1;
  
  	/*
  	 * Turn on "set -x" inheritance by default.
  	 */
  	Flag(FXTRACEREC) = 1;
  
  	/* define built-in commands and see if we were called as one */
  	ktinit(APERM, &builtins,
  	    /* currently up to 54 builtins: 75% of 128 = 2^7 */
  	    7);
  	for (i = 0; mkshbuiltins[i].name != NULL; i++)
  		if (!strcmp(ccp, builtin(mkshbuiltins[i].name,
  		    mkshbuiltins[i].func)))
  			Flag(FAS_BUILTIN) = 1;
  
  	if (!Flag(FAS_BUILTIN)) {
  		/* check for -T option early */
  		argi = parse_args(argv, OF_FIRSTTIME, NULL);
  		if (argi < 0)
  			return (1);
  
  #if defined(MKSH_BINSHPOSIX) || defined(MKSH_BINSHREDUCED)
  		/* are we called as -sh or /bin/sh or so? */
  		if (!strcmp(ccp, "sh" MKSH_EXE_EXT)) {
  			/* either also turns off braceexpand */
  #ifdef MKSH_BINSHPOSIX
  			/* enable better POSIX conformance */
  			change_flag(FPOSIX, OF_FIRSTTIME, true);
  #endif
  #ifdef MKSH_BINSHREDUCED
  			/* enable kludge/compat mode */
  			change_flag(FSH, OF_FIRSTTIME, true);
  #endif
  		}
  #endif
  	}
  
  	initvar();
  
  	inittraps();
  
  	coproc_init();
  
  	/* set up variable and command dictionaries */
  	ktinit(APERM, &taliases, 0);
  	ktinit(APERM, &aliases, 0);
  #ifndef MKSH_NOPWNAM
  	ktinit(APERM, &homedirs, 0);
  #endif
  
  	/* define shell keywords */
  	initkeywords();
  
  	init_histvec();
  
  	/* initialise tty size before importing environment */
  	change_winsz();
  
  #ifdef _PATH_DEFPATH
  	def_path = _PATH_DEFPATH;
  #else
  #ifdef _CS_PATH
  	if ((k = confstr(_CS_PATH, NULL, 0)) > 0 &&
  	    confstr(_CS_PATH, cp = alloc(k + 1, APERM), k + 1) == k + 1)
  		def_path = cp;
  	else
  #endif
  		/*
  		 * this is uniform across all OSes unless it
  		 * breaks somewhere hard; don't try to optimise,
  		 * e.g. add stuff for Interix or remove /usr
  		 * for HURD, because e.g. Debian GNU/HURD is
  		 * "keeping a regular /usr"; this is supposed
  		 * to be a sane 'basic' default PATH
  		 */
  		def_path = MKSH_UNIXROOT "/bin" MKSH_PATHSEPS
  		    MKSH_UNIXROOT "/usr/bin" MKSH_PATHSEPS
  		    MKSH_UNIXROOT "/sbin" MKSH_PATHSEPS
  		    MKSH_UNIXROOT "/usr/sbin";
  #endif
  
  	/*
  	 * Set PATH to def_path (will set the path global variable).
  	 * (import of environment below will probably change this setting).
  	 */
  	vp = global(TPATH);
  	/* setstr can't fail here */
  	setstr(vp, def_path, KSH_RETURN_ERROR);
  
  #ifndef MKSH_NO_CMDLINE_EDITING
  	/*
  	 * Set edit mode to emacs by default, may be overridden
  	 * by the environment or the user. Also, we want tab completion
  	 * on in vi by default.
  	 */
  	change_flag(FEMACS, OF_SPECIAL, true);
  #if !MKSH_S_NOVI
  	Flag(FVITABCOMPLETE) = 1;
  #endif
  #endif
  
  	/* import environment */
  	init_environ();
  
  	/* for security */
  	typeset(TinitIFS, 0, 0, 0, 0);
  
  	/* assign default shell variable values */
  	typeset("PATHSEP=" MKSH_PATHSEPS, 0, 0, 0, 0);
  	substitute(initsubs, 0);
  
  	/* Figure out the current working directory and set $PWD */
  	vp = global(TPWD);
  	cp = str_val(vp);
  	/* Try to use existing $PWD if it is valid */
  	set_current_wd((mksh_abspath(cp) && test_eval(NULL, TO_FILEQ, cp,
  	    Tdot, true)) ? cp : NULL);
  	if (current_wd[0])
  		simplify_path(current_wd);
  	/* Only set pwd if we know where we are or if it had a bogus value */
  	if (current_wd[0] || *cp)
  		/* setstr can't fail here */
  		setstr(vp, current_wd, KSH_RETURN_ERROR);
  
  	for (wp = initcoms; *wp != NULL; wp++) {
  		c_builtin(wp);
  		while (*wp != NULL)
  			wp++;
  	}
  	setint_n(global("OPTIND"), 1, 10);
  
  	kshuid = getuid();
  	kshgid = getgid();
  	kshegid = getegid();
  
  	safe_prompt = ksheuid ? "$ " : "# ";
  	vp = global("PS1");
  	/* Set PS1 if unset or we are root and prompt doesn't contain a # */
  	if (!(vp->flag & ISSET) ||
  	    (!ksheuid && !strchr(str_val(vp), '#')))
  		/* setstr can't fail here */
  		setstr(vp, safe_prompt, KSH_RETURN_ERROR);
  	setint_n((vp = global("BASHPID")), 0, 10);
  	vp->flag |= INT_U;
  	setint_n((vp = global("PGRP")), (mksh_uari_t)kshpgrp, 10);
  	vp->flag |= INT_U;
  	setint_n((vp = global("PPID")), (mksh_uari_t)kshppid, 10);
  	vp->flag |= INT_U;
  	setint_n((vp = global("USER_ID")), (mksh_uari_t)ksheuid, 10);
  	vp->flag |= INT_U;
  	setint_n((vp = global("KSHUID")), (mksh_uari_t)kshuid, 10);
  	vp->flag |= INT_U;
  	setint_n((vp = global("KSHEGID")), (mksh_uari_t)kshegid, 10);
  	vp->flag |= INT_U;
  	setint_n((vp = global("KSHGID")), (mksh_uari_t)kshgid, 10);
  	vp->flag |= INT_U;
  	setint_n((vp = global("RANDOM")), rndsetup(), 10);
  	vp->flag |= INT_U;
  	setint_n((vp_pipest = global("PIPESTATUS")), 0, 10);
  
  	/* Set this before parsing arguments */
  	Flag(FPRIVILEGED) = (kshuid != ksheuid || kshgid != kshegid) ? 2 : 0;
  
  	/* record if monitor is set on command line (see j_init() in jobs.c) */
  #ifndef MKSH_UNEMPLOYED
  	Flag(FMONITOR) = 127;
  #endif
  	/* this to note if utf-8 mode is set on command line (see below) */
  	UTFMODE = 2;
  
  	if (!Flag(FAS_BUILTIN)) {
  		argi = parse_args(argv, OF_CMDLINE, NULL);
  		if (argi < 0)
  			return (1);
  	}
  
  	/* process this later only, default to off (hysterical raisins) */
  	utf_flag = UTFMODE;
  	UTFMODE = 0;
  
  	if (Flag(FAS_BUILTIN)) {
  		/* auto-detect from environment variables, always */
  		utf_flag = 3;
  	} else if (Flag(FCOMMAND)) {
  		s = pushs(SSTRINGCMDLINE, ATEMP);
  		if (!(s->start = s->str = argv[argi++]))
  			errorf(Tf_optfoo, "", "", 'c', Treq_arg);
  		while (*s->str) {
  			if (ctype(*s->str, C_QUOTE))
  				break;
  			s->str++;
  		}
  		if (!*s->str)
  			s->flags |= SF_MAYEXEC;
  		s->str = s->start;
  #ifdef MKSH_MIDNIGHTBSD01ASH_COMPAT
  		/* compatibility to MidnightBSD 0.1 /bin/sh (kludge) */
  		if (Flag(FSH) && argv[argi] && !strcmp(argv[argi], "--"))
  			++argi;
  #endif
  		if (argv[argi])
  			kshname = argv[argi++];
  	} else if (argi < argc && !Flag(FSTDIN)) {
  		s = pushs(SFILE, ATEMP);
  #ifdef __OS2__
  		/*
  		 * A bug in OS/2 extproc (like shebang) handling makes
  		 * it not pass the full pathname of a script, so we need
  		 * to search for it. This changes the behaviour of a
  		 * simple "mksh foo", but can't be helped.
  		 */
  		s->file = argv[argi++];
  		if (search_access(s->file, X_OK) != 0)
  			s->file = search_path(s->file, path, X_OK, NULL);
  		if (!s->file || !*s->file)
  			s->file = argv[argi - 1];
  #else
  		s->file = argv[argi++];
  #endif
  		s->u.shf = shf_open(s->file, O_RDONLY | O_MAYEXEC, 0,
  		    SHF_MAPHI | SHF_CLEXEC);
  		if (s->u.shf == NULL) {
  			shl_stdout_ok = false;
  			warningf(true, Tf_sD_s, s->file, cstrerror(errno));
  			/* mandated by SUSv4 */
  			exstat = 127;
  			unwind(LERROR);
  		}
  		kshname = s->file;
  	} else {
  		Flag(FSTDIN) = 1;
  		s = pushs(SSTDIN, ATEMP);
  		s->file = "<stdin>";
  		s->u.shf = shf_fdopen(0, SHF_RD | can_seek(0),
  		    NULL);
  		if (isatty(0) && isatty(2)) {
  			Flag(FTALKING) = Flag(FTALKING_I) = 1;
  			/* The following only if isatty(0) */
  			s->flags |= SF_TTY;
  			s->u.shf->flags |= SHF_INTERRUPT;
  			s->file = NULL;
  		}
  	}
  
  	/* this bizarreness is mandated by POSIX */
  	if (fstat(0, &s_stdin) >= 0 && S_ISCHR(s_stdin.st_mode) &&
  	    Flag(FTALKING))
  		reset_nonblock(0);
  
  	/* initialise job control */
  	j_init();
  	/* do this after j_init() which calls tty_init_state() */
  	if (Flag(FTALKING)) {
  		if (utf_flag == 2) {
  #ifndef MKSH_ASSUME_UTF8
  			/* auto-detect from locale or environment */
  			utf_flag = 4;
  #else /* this may not be an #elif */
  #if MKSH_ASSUME_UTF8
  			utf_flag = 1;
  #else
  			/* always disable UTF-8 (for interactive) */
  			utf_flag = 0;
  #endif
  #endif
  		}
  #ifndef MKSH_NO_CMDLINE_EDITING
  		x_init();
  #endif
  	}
  
  #ifdef SIGWINCH
  	sigtraps[SIGWINCH].flags |= TF_SHELL_USES;
  	setsig(&sigtraps[SIGWINCH], x_sigwinch,
  	    SS_RESTORE_ORIG|SS_FORCE|SS_SHTRAP);
  #endif
  
  	l = e->loc;
  	if (Flag(FAS_BUILTIN)) {
  		l->argc = argc;
  		l->argv = argv;
  		l->argv[0] = ccp;
  	} else {
  		l->argc = argc - argi;
  		/*
  		 * allocate a new array because otherwise, when we modify
  		 * it in-place, ps(1) output changes; the meaning of argc
  		 * here is slightly different as it excludes kshname, and
  		 * we add a trailing NULL sentinel as well
  		 */
  		l->argv = alloc2(l->argc + 2, sizeof(void *), APERM);
  		l->argv[0] = kshname;
  		memcpy(&l->argv[1], &argv[argi], l->argc * sizeof(void *));
  		l->argv[l->argc + 1] = NULL;
  		getopts_reset(1);
  	}
  
  	/* divine the initial state of the utf8-mode Flag */
  	ccp = null;
  	switch (utf_flag) {
  
  	/* auto-detect from locale or environment */
  	case 4:
  #if HAVE_SETLOCALE_CTYPE
  		ccp = setlocale(LC_CTYPE, "");
  #if HAVE_LANGINFO_CODESET
  		if (!isuc(ccp))
  			ccp = nl_langinfo(CODESET);
  #endif
  		if (!isuc(ccp))
  			ccp = null;
  #endif
  		/* FALLTHROUGH */
  
  	/* auto-detect from environment */
  	case 3:
  		/* these were imported from environ earlier */
  		if (ccp == null)
  			ccp = str_val(global("LC_ALL"));
  		if (ccp == null)
  			ccp = str_val(global("LC_CTYPE"));
  		if (ccp == null)
  			ccp = str_val(global("LANG"));
  		UTFMODE = isuc(ccp);
  		break;
  
  	/* not set on command line, not FTALKING */
  	case 2:
  	/* unknown values */
  	default:
  		utf_flag = 0;
  		/* FALLTHROUGH */
  
  	/* known values */
  	case 1:
  	case 0:
  		UTFMODE = utf_flag;
  		break;
  	}
  
  	/* Disable during .profile/ENV reading */
  	restricted_shell = Flag(FRESTRICTED);
  	Flag(FRESTRICTED) = 0;
  	errexit = Flag(FERREXIT);
  	Flag(FERREXIT) = 0;
  
  	/*
  	 * Do this before profile/$ENV so that if it causes problems in them,
  	 * user will know why things broke.
  	 */
  	if (!current_wd[0] && Flag(FTALKING))
  		warningf(false, "can't determine current directory");
  
  	if (Flag(FLOGIN))
  		include(MKSH_SYSTEM_PROFILE, 0, NULL, true);
  	if (!Flag(FPRIVILEGED)) {
  		if (Flag(FLOGIN))
  			include(substitute("$HOME/.profile", 0), 0, NULL, true);
  		if (Flag(FTALKING)) {
  			cp = substitute("${ENV:-" MKSHRC_PATH "}", DOTILDE);
  			if (cp[0] != '\0')
  				include(cp, 0, NULL, true);
  		}
  	} else {
  		include(MKSH_SUID_PROFILE, 0, NULL, true);
  		/* turn off -p if not set explicitly */
  		if (Flag(FPRIVILEGED) != 1)
  			change_flag(FPRIVILEGED, OF_INTERNAL, false);
  	}
  
  	if (restricted_shell) {
  		c_builtin(restr_com);
  		/* After typeset command... */
  		Flag(FRESTRICTED) = 1;
  	}
  	Flag(FERREXIT) = errexit;
  
  	if (Flag(FTALKING) && s)
  		hist_init(s);
  	else
  		/* set after ENV */
  		Flag(FTRACKALL) = 1;
  
  	alarm_init();
  
  	*sp = s;
  	*lp = l;
  	return (0);
  }
  
  /* this indirection barrier reduces stack usage during normal operation */
  
  int
  main(int argc, const char *argv[])
  {
  	int rv;
  	Source *s;
  	struct block *l;
  
  	if ((rv = main_init(argc, argv, &s, &l)) == 0) {
  		if (Flag(FAS_BUILTIN)) {
  			rv = c_builtin(l->argv);
  		} else {
  			shell(s, 0);
  			/* NOTREACHED */
  		}
  	}
  	return (rv);
  }
  
  int
  include(const char *name, int argc, const char **argv, bool intr_ok)
  {
  	Source *volatile s = NULL;
  	struct shf *shf;
  	const char **volatile old_argv;
  	volatile int old_argc;
  	int i;
  
  	shf = shf_open(name, O_RDONLY | O_MAYEXEC, 0, SHF_MAPHI | SHF_CLEXEC);
  	if (shf == NULL)
  		return (-1);
  
  	if (argv) {
  		old_argv = e->loc->argv;
  		old_argc = e->loc->argc;
  	} else {
  		old_argv = NULL;
  		old_argc = 0;
  	}
  	newenv(E_INCL);
  	if ((i = kshsetjmp(e->jbuf))) {
  		quitenv(s ? s->u.shf : NULL);
  		if (old_argv) {
  			e->loc->argv = old_argv;
  			e->loc->argc = old_argc;
  		}
  		switch (i) {
  		case LRETURN:
  		case LERROR:
  			/* see below */
  			return (exstat & 0xFF);
  		case LINTR:
  			/*
  			 * intr_ok is set if we are including .profile or $ENV.
  			 * If user ^Cs out, we don't want to kill the shell...
  			 */
  			if (intr_ok && ((exstat & 0xFF) - 128) != SIGTERM)
  				return (1);
  			/* FALLTHROUGH */
  		case LEXIT:
  		case LLEAVE:
  		case LSHELL:
  			unwind(i);
  			/* NOTREACHED */
  		default:
  			internal_errorf(Tunexpected_type, Tunwind, Tsource, i);
  			/* NOTREACHED */
  		}
  	}
  	if (argv) {
  		e->loc->argv = argv;
  		e->loc->argc = argc;
  	}
  	s = pushs(SFILE, ATEMP);
  	s->u.shf = shf;
  	strdupx(s->file, name, ATEMP);
  	i = shell(s, 1);
  	quitenv(s->u.shf);
  	if (old_argv) {
  		e->loc->argv = old_argv;
  		e->loc->argc = old_argc;
  	}
  	/* & 0xff to ensure value not -1 */
  	return (i & 0xFF);
  }
  
  /* spawn a command into a shell optionally keeping track of the line number */
  int
  command(const char *comm, int line)
  {
  	Source *s, *sold = source;
  	int rv;
  
  	s = pushs(SSTRING, ATEMP);
  	s->start = s->str = comm;
  	s->line = line;
  	rv = shell(s, 1);
  	source = sold;
  	return (rv);
  }
  
  /*
   * run the commands from the input source, returning status.
   */
  int
  shell(Source * volatile s, volatile int level)
  {
  	struct op *t;
  	volatile bool wastty = tobool(s->flags & SF_TTY);
  	volatile uint8_t attempts = 13;
  	volatile bool interactive = (level == 0) && Flag(FTALKING);
  	volatile bool sfirst = true;
  	Source *volatile old_source = source;
  	int i;
  
  	newenv(level == 2 ? E_EVAL : E_PARSE);
  	if (interactive)
  		really_exit = false;
  	switch ((i = kshsetjmp(e->jbuf))) {
  	case 0:
  		break;
  	case LBREAK:
  	case LCONTIN:
  		if (level != 2) {
  			source = old_source;
  			quitenv(NULL);
  			internal_errorf(Tf_cant_s, Tshell,
  			    i == LBREAK ? Tbreak : Tcontinue);
  			/* NOTREACHED */
  		}
  		/* assert: interactive == false */
  		/* FALLTHROUGH */
  	case LINTR:
  		/* we get here if SIGINT not caught or ignored */
  	case LERROR:
  	case LSHELL:
  		if (interactive) {
  			if (i == LINTR)
  				shellf("\n");
  			/*
  			 * Reset any eof that was read as part of a
  			 * multiline command.
  			 */
  			if (Flag(FIGNOREEOF) && s->type == SEOF && wastty)
  				s->type = SSTDIN;
  			/*
  			 * Used by exit command to get back to
  			 * top level shell. Kind of strange since
  			 * interactive is set if we are reading from
  			 * a tty, but to have stopped jobs, one only
  			 * needs FMONITOR set (not FTALKING/SF_TTY)...
  			 */
  			/* toss any input we have so far */
  			yyrecursive_pop(true);
  			s->start = s->str = null;
  			retrace_info = NULL;
  			herep = heres;
  			break;
  		}
  		/* FALLTHROUGH */
  	case LEXIT:
  	case LLEAVE:
  	case LRETURN:
  		source = old_source;
  		quitenv(NULL);
  		/* keep on going */
  		unwind(i);
  		/* NOTREACHED */
  	default:
  		source = old_source;
  		quitenv(NULL);
  		internal_errorf(Tunexpected_type, Tunwind, Tshell, i);
  		/* NOTREACHED */
  	}
  	while (/* CONSTCOND */ 1) {
  		if (trap)
  			runtraps(0);
  
  		if (s->next == NULL) {
  			if (Flag(FVERBOSE))
  				s->flags |= SF_ECHO;
  			else
  				s->flags &= ~SF_ECHO;
  		}
  		if (interactive) {
  			j_notify();
  			set_prompt(PS1, s);
  		}
  		t = compile(s, sfirst, true);
  		if (interactive)
  			histsave(&s->line, NULL, HIST_FLUSH, true);
  		sfirst = false;
  		if (!t)
  			goto source_no_tree;
  		if (t->type == TEOF) {
  			if (wastty && Flag(FIGNOREEOF) && --attempts > 0) {
  				shellf("Use 'exit' to leave mksh\n");
  				s->type = SSTDIN;
  			} else if (wastty && !really_exit &&
  			    j_stopped_running()) {
  				really_exit = true;
  				s->type = SSTDIN;
  			} else {
  				/*
  				 * this for POSIX which says EXIT traps
  				 * shall be taken in the environment
  				 * immediately after the last command
  				 * executed.
  				 */
  				if (level == 0)
  					unwind(LEXIT);
  				break;
  			}
  		} else if ((s->flags & SF_MAYEXEC) && t->type == TCOM)
  			t->u.evalflags |= DOTCOMEXEC;
  		if (!Flag(FNOEXEC) || (s->flags & SF_TTY))
  			exstat = execute(t, 0, NULL) & 0xFF;
  
  		if (t->type != TEOF && interactive && really_exit)
  			really_exit = false;
  
   source_no_tree:
  		reclaim();
  	}
  	quitenv(NULL);
  	source = old_source;
  	return (exstat & 0xFF);
  }
  
  /* return to closest error handler or shell(), exit if none found */
  /* note: i MUST NOT be 0 */
  void
  unwind(int i)
  {
  	/*
  	 * This is a kludge. We need to restore everything that was
  	 * changed in the new environment, see cid 1005090337C7A669439
  	 * and 10050903386452ACBF1, but fail to even save things most of
  	 * the time. funcs.c:c_eval() changes FERREXIT temporarily to 0,
  	 * which needs to be restored thus (related to Debian #696823).
  	 * We did not save the shell flags, so we use a special or'd
  	 * value here... this is mostly to clean up behind *other*
  	 * callers of unwind(LERROR) here; exec.c has the regular case.
  	 */
  	if (Flag(FERREXIT) & 0x80) {
  		/* GNU bash does not run this trapsig */
  		trapsig(ksh_SIGERR);
  		Flag(FERREXIT) &= ~0x80;
  	}
  
  	/* ordering for EXIT vs ERR is a bit odd (this is what AT&T ksh does) */
  	if (i == LEXIT || ((i == LERROR || i == LINTR) &&
  	    sigtraps[ksh_SIGEXIT].trap &&
  	    (!Flag(FTALKING) || Flag(FERREXIT)))) {
  		++trap_nested;
  		runtrap(&sigtraps[ksh_SIGEXIT], trap_nested == 1);
  		--trap_nested;
  		i = LLEAVE;
  	} else if (Flag(FERREXIT) == 1 && (i == LERROR || i == LINTR)) {
  		++trap_nested;
  		runtrap(&sigtraps[ksh_SIGERR], trap_nested == 1);
  		--trap_nested;
  		i = LLEAVE;
  	}
  
  	while (/* CONSTCOND */ 1) {
  		switch (e->type) {
  		case E_PARSE:
  		case E_FUNC:
  		case E_INCL:
  		case E_LOOP:
  		case E_ERRH:
  		case E_EVAL:
  			kshlongjmp(e->jbuf, i);
  			/* NOTREACHED */
  		case E_NONE:
  			if (i == LINTR)
  				e->flags |= EF_FAKE_SIGDIE;
  			/* FALLTHROUGH */
  		default:
  			quitenv(NULL);
  		}
  	}
  }
  
  void
  newenv(int type)
  {
  	struct env *ep;
  	char *cp;
  
  	/*
  	 * struct env includes ALLOC_ITEM for alignment constraints
  	 * so first get the actually used memory, then assign it
  	 */
  	cp = alloc(sizeof(struct env) - sizeof(ALLOC_ITEM), ATEMP);
  	/* undo what alloc() did to the malloc result address */
  	ep = (void *)(cp - sizeof(ALLOC_ITEM));
  	/* initialise public members of struct env (not the ALLOC_ITEM) */
  	ainit(&ep->area);
  	ep->oenv = e;
  	ep->loc = e->loc;
  	ep->savefd = NULL;
  	ep->temps = NULL;
  	ep->yyrecursive_statep = NULL;
  	ep->type = type;
  	ep->flags = 0;
  	/* jump buffer is invalid because flags == 0 */
  	e = ep;
  }
  
  void
  quitenv(struct shf *shf)
  {
  	struct env *ep = e;
  	char *cp;
  	int fd;
  
  	yyrecursive_pop(true);
  	while (ep->oenv && ep->oenv->loc != ep->loc)
  		popblock();
  	if (ep->savefd != NULL) {
  		for (fd = 0; fd < NUFILE; fd++)
  			/* if ep->savefd[fd] < 0, means fd was closed */
  			if (ep->savefd[fd])
  				restfd(fd, ep->savefd[fd]);
  		if (ep->savefd[2])
  			/* Clear any write errors */
  			shf_reopen(2, SHF_WR, shl_out);
  	}
  	/*
  	 * Bottom of the stack.
  	 * Either main shell is exiting or cleanup_parents_env() was called.
  	 */
  	if (ep->oenv == NULL) {
  #ifdef DEBUG_LEAKS
  		int i;
  #endif
  
  		if (ep->type == E_NONE) {
  			/* Main shell exiting? */
  #if HAVE_PERSISTENT_HISTORY
  			if (Flag(FTALKING))
  				hist_finish();
  #endif
  			j_exit();
  			if (ep->flags & EF_FAKE_SIGDIE) {
  				int sig = (exstat & 0xFF) - 128;
  
  				/*
  				 * ham up our death a bit (AT&T ksh
  				 * only seems to do this for SIGTERM)
  				 * Don't do it for SIGQUIT, since we'd
  				 * dump a core..
  				 */
  				if ((sig == SIGINT || sig == SIGTERM) &&
  				    (kshpgrp == kshpid)) {
  					setsig(&sigtraps[sig], SIG_DFL,
  					    SS_RESTORE_CURR | SS_FORCE);
  					kill(0, sig);
  				}
  			}
  		}
  		if (shf)
  			shf_close(shf);
  		reclaim();
  #ifdef DEBUG_LEAKS
  #ifndef MKSH_NO_CMDLINE_EDITING
  		x_done();
  #endif
  #ifndef MKSH_NOPROSPECTOFWORK
  		/* block at least SIGCHLD during/after afreeall */
  		sigprocmask(SIG_BLOCK, &sm_sigchld, NULL);
  #endif
  		afreeall(APERM);
  		for (fd = 3; fd < NUFILE; fd++)
  			if ((i = fcntl(fd, F_GETFD, 0)) != -1 &&
  			    (i & FD_CLOEXEC))
  				close(fd);
  		close(2);
  		close(1);
  		close(0);
  #endif
  		exit(exstat & 0xFF);
  	}
  	if (shf)
  		shf_close(shf);
  	reclaim();
  
  	e = e->oenv;
  
  	/* free the struct env - tricky due to the ALLOC_ITEM inside */
  	cp = (void *)ep;
  	afree(cp + sizeof(ALLOC_ITEM), ATEMP);
  }
  
  /* Called after a fork to cleanup stuff left over from parents environment */
  void
  cleanup_parents_env(void)
  {
  	struct env *ep;
  	int fd;
  
  	/*
  	 * Don't clean up temporary files - parent will probably need them.
  	 * Also, can't easily reclaim memory since variables, etc. could be
  	 * anywhere.
  	 */
  
  	/* close all file descriptors hiding in savefd */
  	for (ep = e; ep; ep = ep->oenv) {
  		if (ep->savefd) {
  			for (fd = 0; fd < NUFILE; fd++)
  				if (ep->savefd[fd] > 0)
  					close(ep->savefd[fd]);
  			afree(ep->savefd, &ep->area);
  			ep->savefd = NULL;
  		}
  #ifdef DEBUG_LEAKS
  		if (ep->type != E_NONE)
  			ep->type = E_GONE;
  #endif
  	}
  #ifndef DEBUG_LEAKS
  	e->oenv = NULL;
  #endif
  }
  
  /* Called just before an execve cleanup stuff temporary files */
  void
  cleanup_proc_env(void)
  {
  	struct env *ep;
  
  	for (ep = e; ep; ep = ep->oenv)
  		remove_temps(ep->temps);
  }
  
  /* remove temp files and free ATEMP Area */
  static void
  reclaim(void)
  {
  	struct block *l;
  
  	while ((l = e->loc) && (!e->oenv || e->oenv->loc != l)) {
  		e->loc = l->next;
  		afreeall(&l->area);
  	}
  
  	remove_temps(e->temps);
  	e->temps = NULL;
  
  	/*
  	 * if the memory backing source is reclaimed, things
  	 * will end up badly when a function expecting it to
  	 * be valid is run; a NULL pointer is easily debugged
  	 */
  	if (source && source->areap == &e->area)
  		source = NULL;
  	afreeall(&e->area);
  }
  
  static void
  remove_temps(struct temp *tp)
  {
  	while (tp) {
  		if (tp->pid == procpid)
  			unlink(tp->tffn);
  		tp = tp->next;
  	}
  }
  
  /*
   * Initialise tty_fd. Used for tracking the size of the terminal,
   * saving/resetting tty modes upon forground job completion, and
   * for setting up the tty process group. Return values:
   *	0 = got controlling tty
   *	1 = got terminal but no controlling tty
   *	2 = cannot find a terminal
   *	3 = cannot dup fd
   *	4 = cannot make fd close-on-exec
   * An existing tty_fd is cached if no "better" one could be found,
   * i.e. if tty_devtty was already set or the new would not set it.
   */
  int
  tty_init_fd(void)
  {
  	int fd, rv, eno = 0;
  	bool do_close = false, is_devtty = true;
  
  	if (tty_devtty) {
  		/* already got a tty which is /dev/tty */
  		return (0);
  	}
  
  #ifdef _UWIN
  	/*XXX imake style */
  	if (isatty(3)) {
  		/* fd 3 on UWIN _is_ /dev/tty (or our controlling tty) */
  		fd = 3;
  		goto got_fd;
  	}
  #endif
  	if ((fd = open(T_devtty, O_RDWR, 0)) >= 0) {
  		do_close = true;
  		goto got_fd;
  	}
  	eno = errno;
  
  	if (tty_fd >= 0) {
  		/* already got a non-devtty one */
  		rv = 1;
  		goto out;
  	}
  	is_devtty = false;
  
  	if (isatty((fd = 0)) || isatty((fd = 2)))
  		goto got_fd;
  	/* cannot find one */
  	rv = 2;
  	/* assert: do_close == false */
  	goto out;
  
   got_fd:
  	if ((rv = fcntl(fd, F_DUPFD, FDBASE)) < 0) {
  		eno = errno;
  		rv = 3;
  		goto out;
  	}
  	if (fcntl(rv, F_SETFD, FD_CLOEXEC) < 0) {
  		eno = errno;
  		close(rv);
  		rv = 4;
  		goto out;
  	}
  	tty_fd = rv;
  	tty_devtty = is_devtty;
  	rv = eno = 0;
   out:
  	if (do_close)
  		close(fd);
  	errno = eno;
  	return (rv);
  }
  
  /* A shell error occurred (eg, syntax error, etc.) */
  
  #define VWARNINGF_ERRORPREFIX	1
  #define VWARNINGF_FILELINE	2
  #define VWARNINGF_BUILTIN	4
  #define VWARNINGF_INTERNAL	8
  
  static void vwarningf(unsigned int, const char *, va_list)
      MKSH_A_FORMAT(__printf__, 2, 0);
  
  static void
  vwarningf(unsigned int flags, const char *fmt, va_list ap)
  {
  	if (fmt) {
  		if (flags & VWARNINGF_INTERNAL)
  			shf_fprintf(shl_out, Tf_sD_, "internal error");
  		if (flags & VWARNINGF_ERRORPREFIX)
  			error_prefix(tobool(flags & VWARNINGF_FILELINE));
  		if ((flags & VWARNINGF_BUILTIN) &&
  		    /* not set when main() calls parse_args() */
  		    builtin_argv0 && builtin_argv0 != kshname)
  			shf_fprintf(shl_out, Tf_sD_, builtin_argv0);
  		shf_vfprintf(shl_out, fmt, ap);
  		shf_putchar('\n', shl_out);
  	}
  	shf_flush(shl_out);
  }
  
  void
  errorfx(int rc, const char *fmt, ...)
  {
  	va_list va;
  
  	exstat = rc;
  
  	/* debugging: note that stdout not valid */
  	shl_stdout_ok = false;
  
  	va_start(va, fmt);
  	vwarningf(VWARNINGF_ERRORPREFIX | VWARNINGF_FILELINE, fmt, va);
  	va_end(va);
  	unwind(LERROR);
  }
  
  void
  errorf(const char *fmt, ...)
  {
  	va_list va;
  
  	exstat = 1;
  
  	/* debugging: note that stdout not valid */
  	shl_stdout_ok = false;
  
  	va_start(va, fmt);
  	vwarningf(VWARNINGF_ERRORPREFIX | VWARNINGF_FILELINE, fmt, va);
  	va_end(va);
  	unwind(LERROR);
  }
  
  /* like errorf(), but no unwind is done */
  void
  warningf(bool fileline, const char *fmt, ...)
  {
  	va_list va;
  
  	va_start(va, fmt);
  	vwarningf(VWARNINGF_ERRORPREFIX | (fileline ? VWARNINGF_FILELINE : 0),
  	    fmt, va);
  	va_end(va);
  }
  
  /*
   * Used by built-in utilities to prefix shell and utility name to message
   * (also unwinds environments for special builtins).
   */
  void
  bi_errorf(const char *fmt, ...)
  {
  	va_list va;
  
  	/* debugging: note that stdout not valid */
  	shl_stdout_ok = false;
  
  	exstat = 1;
  
  	va_start(va, fmt);
  	vwarningf(VWARNINGF_ERRORPREFIX | VWARNINGF_FILELINE |
  	    VWARNINGF_BUILTIN, fmt, va);
  	va_end(va);
  
  	/* POSIX special builtins cause non-interactive shells to exit */
  	if (builtin_spec) {
  		builtin_argv0 = NULL;
  		/* may not want to use LERROR here */
  		unwind(LERROR);
  	}
  }
  
  /* Called when something that shouldn't happen does */
  void
  internal_errorf(const char *fmt, ...)
  {
  	va_list va;
  
  	va_start(va, fmt);
  	vwarningf(VWARNINGF_INTERNAL, fmt, va);
  	va_end(va);
  	unwind(LERROR);
  }
  
  void
  internal_warningf(const char *fmt, ...)
  {
  	va_list va;
  
  	va_start(va, fmt);
  	vwarningf(VWARNINGF_INTERNAL, fmt, va);
  	va_end(va);
  }
  
  /* used by error reporting functions to print "ksh: .kshrc[25]: " */
  void
  error_prefix(bool fileline)
  {
  	/* Avoid foo: foo[2]: ... */
  	if (!fileline || !source || !source->file ||
  	    strcmp(source->file, kshname) != 0)
  		shf_fprintf(shl_out, Tf_sD_, kshname + (*kshname == '-'));
  	if (fileline && source && source->file != NULL) {
  		shf_fprintf(shl_out, "%s[%lu]: ", source->file,
  		    (unsigned long)(source->errline ?
  		    source->errline : source->line));
  		source->errline = 0;
  	}
  }
  
  /* printf to shl_out (stderr) with flush */
  void
  shellf(const char *fmt, ...)
  {
  	va_list va;
  
  	if (!initio_done)
  		/* shl_out may not be set up yet... */
  		return;
  	va_start(va, fmt);
  	shf_vfprintf(shl_out, fmt, va);
  	va_end(va);
  	shf_flush(shl_out);
  }
  
  /* printf to shl_stdout (stdout) */
  void
  shprintf(const char *fmt, ...)
  {
  	va_list va;
  
  	if (!shl_stdout_ok)
  		internal_errorf("shl_stdout not valid");
  	va_start(va, fmt);
  	shf_vfprintf(shl_stdout, fmt, va);
  	va_end(va);
  }
  
  /* test if we can seek backwards fd (returns 0 or SHF_UNBUF) */
  int
  can_seek(int fd)
  {
  	struct stat statb;
  
  	return (fstat(fd, &statb) == 0 && !S_ISREG(statb.st_mode) ?
  	    SHF_UNBUF : 0);
  }
  
  #ifdef DF
  int shl_dbg_fd;
  #define NSHF_IOB 4
  #else
  #define NSHF_IOB 3
  #endif
  struct shf shf_iob[NSHF_IOB];
  
  void
  initio(void)
  {
  #ifdef DF
  	const char *lfp;
  #endif
  
  	/* force buffer allocation */
  	shf_fdopen(1, SHF_WR, shl_stdout);
  	shf_fdopen(2, SHF_WR, shl_out);
  	shf_fdopen(2, SHF_WR, shl_xtrace);
  #ifdef DF
  	if ((lfp = getenv("SDMKSH_PATH")) == NULL) {
  		if ((lfp = getenv("HOME")) == NULL || !mksh_abspath(lfp))
  			errorf("can't get home directory");
  		lfp = shf_smprintf(Tf_sSs, lfp, "mksh-dbg.txt");
  	}
  
  	if ((shl_dbg_fd = open(lfp, O_WRONLY | O_APPEND | O_CREAT, 0600)) < 0)
  		errorf("can't open debug output file %s", lfp);
  	if (shl_dbg_fd < FDBASE) {
  		int nfd;
  
  		nfd = fcntl(shl_dbg_fd, F_DUPFD, FDBASE);
  		close(shl_dbg_fd);
  		if ((shl_dbg_fd = nfd) == -1)
  			errorf("can't dup debug output file");
  	}
  	fcntl(shl_dbg_fd, F_SETFD, FD_CLOEXEC);
  	shf_fdopen(shl_dbg_fd, SHF_WR, shl_dbg);
  	DF("=== open ===");
  #endif
  	initio_done = true;
  }
  
  /* A dup2() with error checking */
  int
  ksh_dup2(int ofd, int nfd, bool errok)
  {
  	int rv;
  
  	if (((rv = dup2(ofd, nfd)) < 0) && !errok && (errno != EBADF))
  		errorf(Ttoo_many_files);
  
  #ifdef __ultrix
  	/*XXX imake style */
  	if (rv >= 0)
  		fcntl(nfd, F_SETFD, 0);
  #endif
  
  	return (rv);
  }
  
  /*
   * Move fd from user space (0 <= fd < 10) to shell space (fd >= 10),
   * set close-on-exec flag. See FDBASE in sh.h, maybe 24 not 10 here.
   */
  short
  savefd(int fd)
  {
  	int nfd = fd;
  
  	if (fd < FDBASE && (nfd = fcntl(fd, F_DUPFD, FDBASE)) < 0 &&
  	    (errno == EBADF || errno == EPERM))
  		return (-1);
  	if (nfd < 0 || nfd > SHRT_MAX)
  		errorf(Ttoo_many_files);
  	fcntl(nfd, F_SETFD, FD_CLOEXEC);
  	return ((short)nfd);
  }
  
  void
  restfd(int fd, int ofd)
  {
  	if (fd == 2)
  		shf_flush(&shf_iob[/* fd */ 2]);
  	if (ofd < 0)
  		/* original fd closed */
  		close(fd);
  	else if (fd != ofd) {
  		/*XXX: what to do if this dup fails? */
  		ksh_dup2(ofd, fd, true);
  		close(ofd);
  	}
  }
  
  void
  openpipe(int *pv)
  {
  	int lpv[2];
  
  	if (pipe(lpv) < 0)
  		errorf("can't create pipe - try again");
  	pv[0] = savefd(lpv[0]);
  	if (pv[0] != lpv[0])
  		close(lpv[0]);
  	pv[1] = savefd(lpv[1]);
  	if (pv[1] != lpv[1])
  		close(lpv[1]);
  #ifdef __OS2__
  	setmode(pv[0], O_BINARY);
  	setmode(pv[1], O_BINARY);
  #endif
  }
  
  void
  closepipe(int *pv)
  {
  	close(pv[0]);
  	close(pv[1]);
  }
  
  /*
   * Called by iosetup() (deals with 2>&4, etc.), c_read, c_print to turn
   * a string (the X in 2>&X, read -uX, print -uX) into a file descriptor.
   */
  int
  check_fd(const char *name, int mode, const char **emsgp)
  {
  	int fd, fl;
  
  	if (!name[0] || name[1])
  		goto illegal_fd_name;
  	if (name[0] == 'p')
  		return (coproc_getfd(mode, emsgp));
  	if (!ctype(name[0], C_DIGIT)) {
   illegal_fd_name:
  		if (emsgp)
  			*emsgp = "illegal file descriptor name";
  		return (-1);
  	}
  
  	if ((fl = fcntl((fd = ksh_numdig(name[0])), F_GETFL, 0)) < 0) {
  		if (emsgp)
  			*emsgp = "bad file descriptor";
  		return (-1);
  	}
  	fl &= O_ACCMODE;
  	/*
  	 * X_OK is a kludge to disable this check for dups (x<&1):
  	 * historical shells never did this check (XXX don't know what
  	 * POSIX has to say).
  	 */
  	if (!(mode & X_OK) && fl != O_RDWR && (
  	    ((mode & R_OK) && fl != O_RDONLY) ||
  	    ((mode & W_OK) && fl != O_WRONLY))) {
  		if (emsgp)
  			*emsgp = (fl == O_WRONLY) ?
  			    "fd not open for reading" :
  			    "fd not open for writing";
  		return (-1);
  	}
  	return (fd);
  }
  
  /* Called once from main */
  void
  coproc_init(void)
  {
  	coproc.read = coproc.readw = coproc.write = -1;
  	coproc.njobs = 0;
  	coproc.id = 0;
  }
  
  /* Called by c_read() when eof is read - close fd if it is the co-process fd */
  void
  coproc_read_close(int fd)
  {
  	if (coproc.read >= 0 && fd == coproc.read) {
  		coproc_readw_close(fd);
  		close(coproc.read);
  		coproc.read = -1;
  	}
  }
  
  /*
   * Called by c_read() and by iosetup() to close the other side of the
   * read pipe, so reads will actually terminate.
   */
  void
  coproc_readw_close(int fd)
  {
  	if (coproc.readw >= 0 && coproc.read >= 0 && fd == coproc.read) {
  		close(coproc.readw);
  		coproc.readw = -1;
  	}
  }
  
  /*
   * Called by c_print when a write to a fd fails with EPIPE and by iosetup
   * when co-process input is dup'd
   */
  void
  coproc_write_close(int fd)
  {
  	if (coproc.write >= 0 && fd == coproc.write) {
  		close(coproc.write);
  		coproc.write = -1;
  	}
  }
  
  /*
   * Called to check for existence of/value of the co-process file descriptor.
   * (Used by check_fd() and by c_read/c_print to deal with -p option).
   */
  int
  coproc_getfd(int mode, const char **emsgp)
  {
  	int fd = (mode & R_OK) ? coproc.read : coproc.write;
  
  	if (fd >= 0)
  		return (fd);
  	if (emsgp)
  		*emsgp = "no coprocess";
  	return (-1);
  }
  
  /*
   * called to close file descriptors related to the coprocess (if any)
   * Should be called with SIGCHLD blocked.
   */
  void
  coproc_cleanup(int reuse)
  {
  	/* This to allow co-processes to share output pipe */
  	if (!reuse || coproc.readw < 0 || coproc.read < 0) {
  		if (coproc.read >= 0) {
  			close(coproc.read);
  			coproc.read = -1;
  		}
  		if (coproc.readw >= 0) {
  			close(coproc.readw);
  			coproc.readw = -1;
  		}
  	}
  	if (coproc.write >= 0) {
  		close(coproc.write);
  		coproc.write = -1;
  	}
  }
  
  struct temp *
  maketemp(Area *ap, Temp_type type, struct temp **tlist)
  {
  	char *cp;
  	size_t len;
  	int i, j;
  	struct temp *tp;
  	const char *dir;
  	struct stat sb;
  
  	dir = tmpdir ? tmpdir : MKSH_DEFAULT_TMPDIR;
  	/* add "/shXXXXXX.tmp" plus NUL */
  	len = strlen(dir);
  	checkoktoadd(len, offsetof(struct temp, tffn[0]) + 14);
  	tp = alloc(offsetof(struct temp, tffn[0]) + 14 + len, ap);
  
  	tp->shf = NULL;
  	tp->pid = procpid;
  	tp->type = type;
  
  	if (stat(dir, &sb) || !S_ISDIR(sb.st_mode)) {
  		tp->tffn[0] = '\0';
  		goto maketemp_out;
  	}
  
  	cp = (void *)tp;
  	cp += offsetof(struct temp, tffn[0]);
  	memcpy(cp, dir, len);
  	cp += len;
  	memcpy(cp, "/shXXXXXX.tmp", 14);
  	/* point to the first of six Xes */
  	cp += 3;
  
  	/* cyclically attempt to open a temporary file */
  	do {
  		/* generate random part of filename */
  		len = 0;
  		do {
  			cp[len++] = digits_lc[rndget() % 36];
  		} while (len < 6);
  
  		/* check if this one works */
  		if ((i = binopen3(tp->tffn, O_CREAT | O_EXCL | O_RDWR,
  		    0600)) < 0 && errno != EEXIST)
  			goto maketemp_out;
  	} while (i < 0);
  
  	if (type == TT_FUNSUB) {
  		/* map us high and mark as close-on-exec */
  		if ((j = savefd(i)) != i) {
  			close(i);
  			i = j;
  		}
  
  		/* operation mode for the shf */
  		j = SHF_RD;
  	} else
  		j = SHF_WR;
  
  	/* shf_fdopen cannot fail, so no fd leak */
  	tp->shf = shf_fdopen(i, j, NULL);
  
   maketemp_out:
  	tp->next = *tlist;
  	*tlist = tp;
  	return (tp);
  }
  
  /*
   * We use a similar collision resolution algorithm as Python 2.5.4
   * but with a slightly tweaked implementation written from scratch.
   */
  
  #define	INIT_TBLSHIFT	3	/* initial table shift (2^3 = 8) */
  #define PERTURB_SHIFT	5	/* see Python 2.5.4 Objects/dictobject.c */
  
  static void tgrow(struct table *);
  static int tnamecmp(const void *, const void *);
  
  static void
  tgrow(struct table *tp)
  {
  	size_t i, j, osize, mask, perturb;
  	struct tbl *tblp, **pp;
  	struct tbl **ntblp, **otblp = tp->tbls;
  
  	if (tp->tshift > 29)
  		internal_errorf("hash table size limit reached");
  
  	/* calculate old size, new shift and new size */
  	osize = (size_t)1 << (tp->tshift++);
  	i = osize << 1;
  
  	ntblp = alloc2(i, sizeof(struct tbl *), tp->areap);
  	/* multiplication cannot overflow: alloc2 checked that */
  	memset(ntblp, 0, i * sizeof(struct tbl *));
  
  	/* table can get very full when reaching its size limit */
  	tp->nfree = (tp->tshift == 30) ? 0x3FFF0000UL :
  	    /* but otherwise, only 75% */
  	    ((i * 3) / 4);
  	tp->tbls = ntblp;
  	if (otblp == NULL)
  		return;
  
  	mask = i - 1;
  	for (i = 0; i < osize; i++)
  		if ((tblp = otblp[i]) != NULL) {
  			if ((tblp->flag & DEFINED)) {
  				/* search for free hash table slot */
  				j = perturb = tblp->ua.hval;
  				goto find_first_empty_slot;
   find_next_empty_slot:
  				j = (j << 2) + j + perturb + 1;
  				perturb >>= PERTURB_SHIFT;
   find_first_empty_slot:
  				pp = &ntblp[j & mask];
  				if (*pp != NULL)
  					goto find_next_empty_slot;
  				/* found an empty hash table slot */
  				*pp = tblp;
  				tp->nfree--;
  			} else if (!(tblp->flag & FINUSE)) {
  				afree(tblp, tp->areap);
  			}
  		}
  	afree(otblp, tp->areap);
  }
  
  void
  ktinit(Area *ap, struct table *tp, uint8_t initshift)
  {
  	tp->areap = ap;
  	tp->tbls = NULL;
  	tp->tshift = ((initshift > INIT_TBLSHIFT) ?
  	    initshift : INIT_TBLSHIFT) - 1;
  	tgrow(tp);
  }
  
  /* table, name (key) to search for, hash(name), rv pointer to tbl ptr */
  struct tbl *
  ktscan(struct table *tp, const char *name, uint32_t h, struct tbl ***ppp)
  {
  	size_t j, perturb, mask;
  	struct tbl **pp, *p;
  
  	mask = ((size_t)1 << (tp->tshift)) - 1;
  	/* search for hash table slot matching name */
  	j = perturb = h;
  	goto find_first_slot;
   find_next_slot:
  	j = (j << 2) + j + perturb + 1;
  	perturb >>= PERTURB_SHIFT;
   find_first_slot:
  	pp = &tp->tbls[j & mask];
  	if ((p = *pp) != NULL && (p->ua.hval != h || !(p->flag & DEFINED) ||
  	    strcmp(p->name, name)))
  		goto find_next_slot;
  	/* p == NULL if not found, correct found entry otherwise */
  	if (ppp)
  		*ppp = pp;
  	return (p);
  }
  
  /* table, name (key) to enter, hash(n) */
  struct tbl *
  ktenter(struct table *tp, const char *n, uint32_t h)
  {
  	struct tbl **pp, *p;
  	size_t len;
  
   Search:
  	if ((p = ktscan(tp, n, h, &pp)))
  		return (p);
  
  	if (tp->nfree == 0) {
  		/* too full */
  		tgrow(tp);
  		goto Search;
  	}
  
  	/* create new tbl entry */
  	len = strlen(n);
  	checkoktoadd(len, offsetof(struct tbl, name[0]) + 1);
  	p = alloc(offsetof(struct tbl, name[0]) + ++len, tp->areap);
  	p->flag = 0;
  	p->type = 0;
  	p->areap = tp->areap;
  	p->ua.hval = h;
  	p->u2.field = 0;
  	p->u.array = NULL;
  	memcpy(p->name, n, len);
  
  	/* enter in tp->tbls */
  	tp->nfree--;
  	*pp = p;
  	return (p);
  }
  
  void
  ktwalk(struct tstate *ts, struct table *tp)
  {
  	ts->left = (size_t)1 << (tp->tshift);
  	ts->next = tp->tbls;
  }
  
  struct tbl *
  ktnext(struct tstate *ts)
  {
  	while (--ts->left >= 0) {
  		struct tbl *p = *ts->next++;
  		if (p != NULL && (p->flag & DEFINED))
  			return (p);
  	}
  	return (NULL);
  }
  
  static int
  tnamecmp(const void *p1, const void *p2)
  {
  	const struct tbl *a = *((const struct tbl * const *)p1);
  	const struct tbl *b = *((const struct tbl * const *)p2);
  
  	return (ascstrcmp(a->name, b->name));
  }
  
  struct tbl **
  ktsort(struct table *tp)
  {
  	size_t i;
  	struct tbl **p, **sp, **dp;
  
  	/*
  	 * since the table is never entirely full, no need to reserve
  	 * additional space for the trailing NULL appended below
  	 */
  	i = (size_t)1 << (tp->tshift);
  	p = alloc2(i, sizeof(struct tbl *), ATEMP);
  	sp = tp->tbls;		/* source */
  	dp = p;			/* dest */
  	while (i--)
  		if ((*dp = *sp++) != NULL && (((*dp)->flag & DEFINED) ||
  		    ((*dp)->flag & ARRAY)))
  			dp++;
  	qsort(p, (i = dp - p), sizeof(struct tbl *), tnamecmp);
  	p[i] = NULL;
  	return (p);
  }
  
  #ifdef SIGWINCH
  static void
  x_sigwinch(int sig MKSH_A_UNUSED)
  {
  	/* this runs inside interrupt context, with errno saved */
  
  	got_winch = 1;
  }
  #endif
  
  #ifdef DF
  void
  DF(const char *fmt, ...)
  {
  	va_list args;
  	struct timeval tv;
  	mirtime_mjd mjd;
  
  	mksh_lockfd(shl_dbg_fd);
  	mksh_TIME(tv);
  	timet2mjd(&mjd, tv.tv_sec);
  	shf_fprintf(shl_dbg, "[%02u:%02u:%02u (%u) %u.%06u] ",
  	    (unsigned)mjd.sec / 3600, ((unsigned)mjd.sec / 60) % 60,
  	    (unsigned)mjd.sec % 60, (unsigned)getpid(),
  	    (unsigned)tv.tv_sec, (unsigned)tv.tv_usec);
  	va_start(args, fmt);
  	shf_vfprintf(shl_dbg, fmt, args);
  	va_end(args);
  	shf_putc('\n', shl_dbg);
  	shf_flush(shl_dbg);
  	mksh_unlkfd(shl_dbg_fd);
  }
  #endif
  
  void
  x_mkraw(int fd, mksh_ttyst *ocb, bool forread)
  {
  	mksh_ttyst cb;
  
  	if (ocb)
  		mksh_tcget(fd, ocb);
  	else
  		ocb = &tty_state;
  
  	cb = *ocb;
  	if (forread) {
  		cb.c_iflag &= ~(ISTRIP);
  		cb.c_lflag &= ~(ICANON) | ECHO;
  	} else {
  		cb.c_iflag &= ~(INLCR | ICRNL | ISTRIP);
  		cb.c_lflag &= ~(ISIG | ICANON | ECHO);
  	}
  #if defined(VLNEXT) && defined(_POSIX_VDISABLE)
  	/* OSF/1 processes lnext when ~icanon */
  	cb.c_cc[VLNEXT] = _POSIX_VDISABLE;
  #endif
  	/* SunOS 4.1.x and OSF/1 process discard(flush) when ~icanon */
  #if defined(VDISCARD) && defined(_POSIX_VDISABLE)
  	cb.c_cc[VDISCARD] = _POSIX_VDISABLE;
  #endif
  	cb.c_cc[VTIME] = 0;
  	cb.c_cc[VMIN] = 1;
  
  	mksh_tcset(fd, &cb);
  }
  
  #ifdef MKSH_ENVDIR
  static void
  init_environ(void)
  {
  	char *xp;
  	ssize_t n;
  	XString xs;
  	struct shf *shf;
  	DIR *dirp;
  	struct dirent *dent;
  
  	if ((dirp = opendir(MKSH_ENVDIR)) == NULL) {
  		warningf(false, "cannot read environment from %s: %s",
  		    MKSH_ENVDIR, cstrerror(errno));
  		return;
  	}
  	XinitN(xs, 256, ATEMP);
   read_envfile:
  	errno = 0;
  	if ((dent = readdir(dirp)) != NULL) {
  		if (skip_varname(dent->d_name, true)[0] == '\0') {
  			xp = shf_smprintf(Tf_sSs, MKSH_ENVDIR, dent->d_name);
  			if (!(shf = shf_open(xp, O_RDONLY, 0, 0))) {
  				warningf(false,
  				    "cannot read environment %s from %s: %s",
  				    dent->d_name, MKSH_ENVDIR,
  				    cstrerror(errno));
  				goto read_envfile;
  			}
  			afree(xp, ATEMP);
  			n = strlen(dent->d_name);
  			xp = Xstring(xs, xp);
  			XcheckN(xs, xp, n + 32);
  			memcpy(xp, dent->d_name, n);
  			xp += n;
  			*xp++ = '=';
  			while ((n = shf_read(xp, Xnleft(xs, xp), shf)) > 0) {
  				xp += n;
  				if (Xnleft(xs, xp) <= 0)
  					XcheckN(xs, xp, Xlength(xs, xp));
  			}
  			if (n < 0) {
  				warningf(false,
  				    "cannot read environment %s from %s: %s",
  				    dent->d_name, MKSH_ENVDIR,
  				    cstrerror(shf_errno(shf)));
  			} else {
  				*xp = '\0';
  				xp = Xstring(xs, xp);
  				rndpush(xp);
  				typeset(xp, IMPORT | EXPORT, 0, 0, 0);
  			}
  			shf_close(shf);
  		}
  		goto read_envfile;
  	} else if (errno)
  		warningf(false, "cannot read environment from %s: %s",
  		    MKSH_ENVDIR, cstrerror(errno));
  	closedir(dirp);
  	Xfree(xs, xp);
  }
  #else
  extern char **environ;
  
  static void
  init_environ(void)
  {
  	const char **wp;
  
  	if (environ == NULL)
  		return;
  
  	wp = (const char **)environ;
  	while (*wp != NULL) {
  		rndpush(*wp);
  		typeset(*wp, IMPORT | EXPORT, 0, 0, 0);
  		++wp;
  	}
  }
  #endif
  
  #ifdef MKSH_EARLY_LOCALE_TRACKING
  void
  recheck_ctype(void)
  {
  	const char *ccp;
  	uint8_t old_utfmode = UTFMODE;
  
  	ccp = str_val(global("LC_ALL"));
  	if (ccp == null)
  		ccp = str_val(global("LC_CTYPE"));
  	if (ccp == null)
  		ccp = str_val(global("LANG"));
  	UTFMODE = isuc(ccp);
  #if HAVE_SETLOCALE_CTYPE
  	ccp = setlocale(LC_CTYPE, ccp);
  #if HAVE_LANGINFO_CODESET
  	if (!isuc(ccp))
  		ccp = nl_langinfo(CODESET);
  #endif
  	if (isuc(ccp))
  		UTFMODE = 1;
  #endif
  
  	if (Flag(FPOSIX) && UTFMODE && !old_utfmode)
  		warningf(true, "early locale tracking enabled UTF-8 mode while in POSIX mode, you are now noncompliant");
  }
  #endif
  