Add mksh from CVS 2010/08/24 as system/core/mksh module

Both shells (ash from system/core/sh, and mksh) are built by
default but only the one where $(TARGET_SHELL) is set to is
actually installed (the shell and the mkshrc configuration
file are tagged shell_mksh for this to work).

Signed-off-by: Thorsten Glaser <tg@mirbsd.org>
diff --git a/mksh/src/main.c b/mksh/src/main.c
new file mode 100644
index 0000000..4c7d4a1
--- /dev/null
+++ b/mksh/src/main.c
@@ -0,0 +1,1480 @@
+/*	$OpenBSD: main.c,v 1.46 2010/05/19 17:36:08 jasper Exp $	*/
+/*	$OpenBSD: tty.c,v 1.9 2006/03/14 22:08:01 deraadt Exp $	*/
+/*	$OpenBSD: io.c,v 1.22 2006/03/17 16:30:13 millert Exp $	*/
+/*	$OpenBSD: table.c,v 1.13 2009/01/17 22:06:44 millert Exp $	*/
+
+/*-
+ * Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+ *	Thorsten Glaser <tg@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 1.167 2010/07/04 17:45:15 tg Exp $");
+
+extern char **environ;
+
+#if !HAVE_SETRESUGID
+extern uid_t kshuid;
+extern gid_t kshgid, kshegid;
+#endif
+
+#ifndef MKSHRC_PATH
+#define MKSHRC_PATH	"~/.mkshrc"
+#endif
+
+#ifndef MKSH_DEFAULT_TMPDIR
+#define MKSH_DEFAULT_TMPDIR	"/tmp"
+#endif
+
+static void reclaim(void);
+static void remove_temps(struct temp *);
+void chvt_reinit(void);
+Source *mksh_init(int, const char *[]);
+#ifdef SIGWINCH
+static void x_sigwinch(int);
+#endif
+
+static const char initifs[] = "IFS= \t\n";
+
+static const char initsubs[] =
+    "${PS2=> } ${PS3=#? } ${PS4=+ } ${SECONDS=0} ${TMOUT=0}";
+
+static const char *initcoms[] = {
+	T_typeset, "-r", initvsn, NULL,
+	T_typeset, "-x", "HOME", "PATH", "RANDOM", "SHELL", NULL,
+	T_typeset, "-i10", "COLUMNS", "LINES", "OPTIND", "PGRP", "PPID",
+	    "RANDOM", "SECONDS", "TMOUT", "USER_ID", NULL,
+	"alias",
+	"integer=typeset -i",
+	T_local_typeset,
+	"hash=alias -t",	/* not "alias -t --": hash -r needs to work */
+	"type=whence -v",
+#ifndef MKSH_UNEMPLOYED
+	"stop=kill -STOP",
+	"suspend=kill -STOP $$",
+#endif
+	"autoload=typeset -fu",
+	"functions=typeset -f",
+	"history=fc -l",
+	"nameref=typeset -n",
+	"nohup=nohup ",
+	r_fc_e_,
+	"source=PATH=$PATH:. command .",
+	"login=exec login",
+	NULL,
+	 /* this is what AT&T ksh seems to track, with the addition of emacs */
+	"alias", "-tU",
+	"cat", "cc", "chmod", "cp", "date", "ed", "emacs", "grep", "ls",
+	"make", "mv", "pr", "rm", "sed", "sh", "vi", "who", NULL,
+	NULL
+};
+
+static int initio_done;
+
+struct env *e = &kshstate_v.env_;
+
+void
+chvt_reinit(void)
+{
+	kshpid = procpid = getpid();
+	ksheuid = geteuid();
+	kshpgrp = getpgrp();
+	kshppid = getppid();
+}
+
+Source *
+mksh_init(int argc, const char *argv[])
+{
+	int argi, i;
+	Source *s;
+	struct block *l;
+	unsigned char restricted, errexit, utf_flag;
+	const char **wp;
+	struct tbl *vp;
+	struct stat s_stdin;
+#if !defined(_PATH_DEFPATH) && defined(_CS_PATH)
+	size_t k;
+	char *cp;
+#endif
+
+	/* do things like getpgrp() et al. */
+	chvt_reinit();
+
+	/* make sure argv[] is sane */
+	if (!*argv) {
+		static const char *empty_argv[] = {
+			"mksh", NULL
+		};
+
+		argv = empty_argv;
+		argc = 1;
+	}
+	kshname = *argv;
+
+	ainit(&aperm);		/* initialise permanent Area */
+
+	/* set up base environment */
+	kshstate_v.env_.type = E_NONE;
+	ainit(&kshstate_v.env_.area);
+	newblock();		/* set up global l->vars and l->funs */
+
+	/* Do this first so output routines (eg, errorf, shellf) can work */
+	initio();
+
+	argi = parse_args(argv, OF_FIRSTTIME, NULL);
+	if (argi < 0)
+		return (NULL);
+
+	initvar();
+
+	initctypes();
+
+	inittraps();
+
+	coproc_init();
+
+	/* set up variable and command dictionaries */
+	ktinit(&taliases, APERM, 0);
+	ktinit(&aliases, APERM, 0);
+#ifndef MKSH_NOPWNAM
+	ktinit(&homedirs, APERM, 0);
+#endif
+
+	/* define shell keywords */
+	initkeywords();
+
+	/* define built-in commands */
+	ktinit(&builtins, APERM,
+	    /* must be 80% of 2^n (currently 44 builtins) */ 64);
+	for (i = 0; mkshbuiltins[i].name != NULL; i++)
+		builtin(mkshbuiltins[i].name, mkshbuiltins[i].func);
+
+	init_histvec();
+
+#ifdef _PATH_DEFPATH
+	def_path = _PATH_DEFPATH;
+#else
+#ifdef _CS_PATH
+	if ((k = confstr(_CS_PATH, NULL, 0)) != (size_t)-1 && k > 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; 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 = "/bin:/usr/bin:/sbin:/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("PATH");
+	/* setstr can't fail here */
+	setstr(vp, def_path, KSH_RETURN_ERROR);
+
+	/* Turn on nohup by default for now - will change to off
+	 * by default once people are aware of its existence
+	 * (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;
+
+	/* 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, 1);
+#if !MKSH_S_NOVI
+	Flag(FVITABCOMPLETE) = 1;
+#endif
+
+#ifdef MKSH_BINSHREDUCED
+	/* set FSH if we're called as -sh or /bin/sh or so */
+	{
+		const char *cc;
+
+		cc = kshname;
+		i = 0; argi = 0;
+		while (cc[i] != '\0')
+			/* the following line matches '-' and '/' ;-) */
+			if ((cc[i++] | 2) == '/')
+				argi = i;
+		if (((cc[argi] | 0x20) == 's') && ((cc[argi + 1] | 0x20) == 'h'))
+			change_flag(FSH, OF_FIRSTTIME, 1);
+	}
+#endif
+
+	/* import environment */
+	if (environ != NULL)
+		for (wp = (const char **)environ; *wp != NULL; wp++)
+			typeset(*wp, IMPORT | EXPORT, 0, 0, 0);
+
+	typeset(initifs, 0, 0, 0, 0);	/* for security */
+
+	/* assign default shell variable values */
+	substitute(initsubs, 0);
+
+	/* Figure out the current working directory and set $PWD */
+	{
+		struct stat s_pwd, s_dot;
+		struct tbl *pwd_v = global("PWD");
+		char *pwd = str_val(pwd_v);
+		char *pwdx = pwd;
+
+		/* Try to use existing $PWD if it is valid */
+		if (pwd[0] != '/' ||
+		    stat(pwd, &s_pwd) < 0 || stat(".", &s_dot) < 0 ||
+		    s_pwd.st_dev != s_dot.st_dev ||
+		    s_pwd.st_ino != s_dot.st_ino)
+			pwdx = NULL;
+		set_current_wd(pwdx);
+		if (current_wd[0])
+			simplify_path(current_wd);
+		/* Only set pwd if we know where we are or if it had a
+		 * bogus value
+		 */
+		if (current_wd[0] || pwd != null)
+			/* setstr can't fail here */
+			setstr(pwd_v, current_wd, KSH_RETURN_ERROR);
+	}
+
+	for (wp = initcoms; *wp != NULL; wp++) {
+		shcomexec(wp);
+		while (*wp != NULL)
+			wp++;
+	}
+	setint(global("COLUMNS"), 0);
+	setint(global("LINES"), 0);
+	setint(global("OPTIND"), 1);
+
+	safe_prompt = ksheuid ? "$ " : "# ";
+	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((vp = global("PGRP")), (mksh_uari_t)kshpgrp);
+	vp->flag |= INT_U;
+	setint((vp = global("PPID")), (mksh_uari_t)kshppid);
+	vp->flag |= INT_U;
+	setint((vp = global("RANDOM")), (mksh_uari_t)evilhash(kshname));
+	vp->flag |= INT_U;
+	setint((vp = global("USER_ID")), (mksh_uari_t)ksheuid);
+	vp->flag |= INT_U;
+
+	/* Set this before parsing arguments */
+#if HAVE_SETRESUGID
+	Flag(FPRIVILEGED) = getuid() != ksheuid || getgid() != getegid();
+#else
+	Flag(FPRIVILEGED) = (kshuid = getuid()) != ksheuid ||
+	    (kshgid = getgid()) != (kshegid = getegid());
+#endif
+
+	/* this to note if monitor is set on command line (see below) */
+#ifndef MKSH_UNEMPLOYED
+	Flag(FMONITOR) = 127;
+#endif
+	/* this to note if utf-8 mode is set on command line (see below) */
+	UTFMODE = 2;
+
+	argi = parse_args(argv, OF_CMDLINE, NULL);
+	if (argi < 0)
+		return (NULL);
+
+	/* process this later only, default to off (hysterical raisins) */
+	utf_flag = UTFMODE;
+	UTFMODE = 0;
+
+	if (Flag(FCOMMAND)) {
+		s = pushs(SSTRING, ATEMP);
+		if (!(s->start = s->str = argv[argi++]))
+			errorf("-c requires an argument");
+#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);
+		s->file = argv[argi++];
+		s->u.shf = shf_open(s->file, O_RDONLY, 0,
+		    SHF_MAPHI | SHF_CLEXEC);
+		if (s->u.shf == NULL) {
+			shl_stdout_ok = 0;
+			warningf(true, "%s: %s", s->file, strerror(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();
+	/* set: 0/1; unset: 2->0 */
+	UTFMODE = utf_flag & 1;
+	/* Do this after j_init(), as tty_fd is not initialised until then */
+	if (Flag(FTALKING)) {
+		if (utf_flag == 2) {
+#ifndef MKSH_ASSUME_UTF8
+#define isuc(x)	(((x) != NULL) && \
+		    (stristr((x), "UTF-8") || stristr((x), "utf8")))
+		/* Check if we're in a UTF-8 locale */
+			const char *ccp;
+
+#if HAVE_SETLOCALE_CTYPE
+			ccp = setlocale(LC_CTYPE, "");
+#if HAVE_LANGINFO_CODESET
+			if (!isuc(ccp))
+				ccp = nl_langinfo(CODESET);
+#endif
+#else
+			/* these were imported from environ earlier */
+			ccp = str_val(global("LC_ALL"));
+			if (ccp == null)
+				ccp = str_val(global("LC_CTYPE"));
+			if (ccp == null)
+				ccp = str_val(global("LANG"));
+#endif
+			UTFMODE = isuc(ccp);
+#undef isuc
+#elif MKSH_ASSUME_UTF8
+			UTFMODE = 1;
+#else
+			UTFMODE = 0;
+#endif
+		}
+		x_init();
+	}
+
+#ifdef SIGWINCH
+	sigtraps[SIGWINCH].flags |= TF_SHELL_USES;
+	setsig(&sigtraps[SIGWINCH], x_sigwinch,
+	    SS_RESTORE_ORIG|SS_FORCE|SS_SHTRAP);
+#endif
+
+	l = e->loc;
+	l->argv = &argv[argi - 1];
+	l->argc = argc - argi;
+	l->argv[0] = kshname;
+	getopts_reset(1);
+
+	/* Disable during .profile/ENV reading */
+	restricted = Flag(FRESTRICTED);
+	Flag(FRESTRICTED) = 0;
+	errexit = Flag(FERREXIT);
+	Flag(FERREXIT) = 0;
+
+	/* Do this before profile/$ENV so that if it causes problems in them,
+	 * user will know why things broke.
+	 */
+	if (!current_wd[0] && Flag(FTALKING))
+		warningf(false, "Cannot determine current working directory");
+
+	if (Flag(FLOGIN)) {
+		include(KSH_SYSTEM_PROFILE, 0, NULL, 1);
+		if (!Flag(FPRIVILEGED))
+			include(substitute("$HOME/.profile", 0), 0,
+			    NULL, 1);
+	}
+	if (Flag(FPRIVILEGED))
+		include("/etc/suid_profile", 0, NULL, 1);
+	else if (Flag(FTALKING)) {
+		char *env_file;
+
+		/* include $ENV */
+		env_file = substitute(substitute("${ENV:-" MKSHRC_PATH "}", 0),
+		    DOTILDE);
+		if (*env_file != '\0')
+			include(env_file, 0, NULL, 1);
+	}
+
+	if (restricted) {
+		static const char *restr_com[] = {
+			T_typeset, "-r", "PATH",
+			"ENV", "SHELL",
+			NULL
+		};
+		shcomexec(restr_com);
+		/* After typeset command... */
+		Flag(FRESTRICTED) = 1;
+	}
+	Flag(FERREXIT) = errexit;
+
+	if (Flag(FTALKING)) {
+		hist_init(s);
+		alarm_init();
+	} else
+		Flag(FTRACKALL) = 1;	/* set after ENV */
+
+	return (s);
+}
+
+int
+main(int argc, const char *argv[])
+{
+	Source *s;
+
+	kshstate_v.lcg_state_ = 5381;
+
+	if ((s = mksh_init(argc, argv))) {
+		/* put more entropy into the LCG */
+		change_random(s, sizeof(*s));
+		/* doesn’t return */
+		shell(s, true);
+	}
+	return (1);
+}
+
+int
+include(const char *name, int argc, const char **argv, int 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, 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);
+	i = sigsetjmp(e->jbuf, 0);
+	if (i) {
+		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:
+			return (exstat & 0xff); /* see below */
+		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 - 128) != SIGTERM)
+				return (1);
+			/* FALLTHROUGH */
+		case LEXIT:
+		case LLEAVE:
+		case LSHELL:
+			unwind(i);
+			/* NOTREACHED */
+		default:
+			internal_errorf("include: %d", 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, false);
+	quitenv(s->u.shf);
+	if (old_argv) {
+		e->loc->argv = old_argv;
+		e->loc->argc = old_argc;
+	}
+	return (i & 0xff);	/* & 0xff to ensure value not -1 */
+}
+
+/* spawn a command into a shell optionally keeping track of the line number */
+int
+command(const char *comm, int line)
+{
+	Source *s;
+
+	s = pushs(SSTRING, ATEMP);
+	s->start = s->str = comm;
+	s->line = line;
+	return (shell(s, false));
+}
+
+/*
+ * run the commands from the input source, returning status.
+ */
+int
+shell(Source * volatile s, volatile int toplevel)
+{
+	struct op *t;
+	volatile int wastty = s->flags & SF_TTY;
+	volatile int attempts = 13;
+	volatile int interactive = Flag(FTALKING) && toplevel;
+	Source *volatile old_source = source;
+	int i;
+
+	s->flags |= SF_FIRST;	/* enable UTF-8 BOM check */
+
+	newenv(E_PARSE);
+	if (interactive)
+		really_exit = 0;
+	i = sigsetjmp(e->jbuf, 0);
+	if (i) {
+		switch (i) {
+		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 */
+				s->start = s->str = null;
+				break;
+			}
+			/* FALLTHROUGH */
+		case LEXIT:
+		case LLEAVE:
+		case LRETURN:
+			source = old_source;
+			quitenv(NULL);
+			unwind(i);	/* keep on going */
+			/* NOTREACHED */
+		default:
+			source = old_source;
+			quitenv(NULL);
+			internal_errorf("shell: %d", i);
+			/* NOTREACHED */
+		}
+	}
+	while (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);
+		if (t != NULL && t->type == TEOF) {
+			if (wastty && Flag(FIGNOREEOF) && --attempts > 0) {
+				shellf("Use 'exit' to leave ksh\n");
+				s->type = SSTDIN;
+			} else if (wastty && !really_exit &&
+			    j_stopped_running()) {
+				really_exit = 1;
+				s->type = SSTDIN;
+			} else {
+				/* this for POSIX which says EXIT traps
+				 * shall be taken in the environment
+				 * immediately after the last command
+				 * executed.
+				 */
+				if (toplevel)
+					unwind(LEXIT);
+				break;
+			}
+		}
+		if (t && (!Flag(FNOEXEC) || (s->flags & SF_TTY)))
+			exstat = execute(t, 0, NULL);
+
+		if (t != NULL && t->type != TEOF && interactive && really_exit)
+			really_exit = 0;
+
+		reclaim();
+	}
+	quitenv(NULL);
+	source = old_source;
+	return (exstat);
+}
+
+/* return to closest error handler or shell(), exit if none found */
+void
+unwind(int i)
+{
+	/* ordering for EXIT vs ERR is a bit odd (this is what AT&T ksh does) */
+	if (i == LEXIT || (Flag(FERREXIT) && (i == LERROR || i == LINTR) &&
+	    sigtraps[SIGEXIT_].trap)) {
+		runtrap(&sigtraps[SIGEXIT_]);
+		i = LLEAVE;
+	} else if (Flag(FERREXIT) && (i == LERROR || i == LINTR)) {
+		runtrap(&sigtraps[SIGERR_]);
+		i = LLEAVE;
+	}
+	while (1) {
+		switch (e->type) {
+		case E_PARSE:
+		case E_FUNC:
+		case E_INCL:
+		case E_LOOP:
+		case E_ERRH:
+			siglongjmp(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) - ALLOC_SIZE, ATEMP);
+	ep = (void *)(cp - ALLOC_SIZE);	/* undo what alloc() did */
+	/* 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->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;
+
+	if (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) {
+		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 - 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();
+		exit(exstat);
+	}
+	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 + ALLOC_SIZE, ATEMP);
+}
+
+/* Called after a fork to cleanup stuff left over from parents environment */
+void
+cleanup_parents_env(void)
+{
+	struct env *ep;
+	int fd;
+
+	mkssert(e != NULL);
+
+	/*
+	 * 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;
+		}
+	}
+	e->oenv = NULL;
+}
+
+/* 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)
+{
+	remove_temps(e->temps);
+	e->temps = NULL;
+	afreeall(&e->area);
+}
+
+static void
+remove_temps(struct temp *tp)
+{
+	for (; tp != NULL; tp = tp->next)
+		if (tp->pid == procpid)
+			unlink(tp->name);
+}
+
+/* Initialise tty_fd. Used for saving/reseting tty modes upon
+ * foreground job completion and for setting up tty process group.
+ */
+void
+tty_init(bool init_ttystate, bool need_tty)
+{
+	bool do_close = true;
+	int tfd;
+
+	if (tty_fd >= 0) {
+		close(tty_fd);
+		tty_fd = -1;
+	}
+	tty_devtty = 1;
+
+#ifdef _UWIN
+	/* XXX imake style */
+	if (isatty(3))
+		tfd = 3;
+	else
+#endif
+	if ((tfd = open("/dev/tty", O_RDWR, 0)) < 0) {
+		tty_devtty = 0;
+		if (need_tty)
+			warningf(false,
+			    "No controlling tty (open /dev/tty: %s)",
+			    strerror(errno));
+	}
+	if (tfd < 0) {
+		do_close = false;
+		if (isatty(0))
+			tfd = 0;
+		else if (isatty(2))
+			tfd = 2;
+		else {
+			if (need_tty)
+				warningf(false,
+				    "Can't find tty file descriptor");
+			return;
+		}
+	}
+	if ((tty_fd = fcntl(tfd, F_DUPFD, FDBASE)) < 0) {
+		if (need_tty)
+			warningf(false, "j_ttyinit: dup of tty fd failed: %s",
+			    strerror(errno));
+	} else if (fcntl(tty_fd, F_SETFD, FD_CLOEXEC) < 0) {
+		if (need_tty)
+			warningf(false,
+			    "j_ttyinit: can't set close-on-exec flag: %s",
+			    strerror(errno));
+		close(tty_fd);
+		tty_fd = -1;
+	} else if (init_ttystate)
+		tcgetattr(tty_fd, &tty_state);
+	if (do_close)
+		close(tfd);
+}
+
+void
+tty_close(void)
+{
+	if (tty_fd >= 0) {
+		close(tty_fd);
+		tty_fd = -1;
+	}
+}
+
+/* A shell error occurred (eg, syntax error, etc.) */
+void
+errorf(const char *fmt, ...)
+{
+	va_list va;
+
+	shl_stdout_ok = 0;	/* debugging: note that stdout not valid */
+	exstat = 1;
+	if (*fmt != 1) {
+		error_prefix(true);
+		va_start(va, fmt);
+		shf_vfprintf(shl_out, fmt, va);
+		va_end(va);
+		shf_putchar('\n', shl_out);
+	}
+	shf_flush(shl_out);
+	unwind(LERROR);
+}
+
+/* like errorf(), but no unwind is done */
+void
+warningf(bool fileline, const char *fmt, ...)
+{
+	va_list va;
+
+	error_prefix(fileline);
+	va_start(va, fmt);
+	shf_vfprintf(shl_out, fmt, va);
+	va_end(va);
+	shf_putchar('\n', shl_out);
+	shf_flush(shl_out);
+}
+
+/* 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;
+
+	shl_stdout_ok = 0;	/* debugging: note that stdout not valid */
+	exstat = 1;
+	if (*fmt != 1) {
+		error_prefix(true);
+		/* not set when main() calls parse_args() */
+		if (builtin_argv0)
+			shf_fprintf(shl_out, "%s: ", builtin_argv0);
+		va_start(va, fmt);
+		shf_vfprintf(shl_out, fmt, va);
+		va_end(va);
+		shf_putchar('\n', shl_out);
+	}
+	shf_flush(shl_out);
+	/* POSIX special builtins and ksh special builtins cause
+	 * non-interactive shells to exit.
+	 * XXX odd use of KEEPASN; also may not want LERROR here
+	 */
+	if (builtin_flag & SPEC_BI) {
+		builtin_argv0 = NULL;
+		unwind(LERROR);
+	}
+}
+
+/* Called when something that shouldn't happen does */
+void
+internal_verrorf(const char *fmt, va_list ap)
+{
+	shf_fprintf(shl_out, "internal error: ");
+	shf_vfprintf(shl_out, fmt, ap);
+	shf_putchar('\n', shl_out);
+	shf_flush(shl_out);
+}
+
+void
+internal_errorf(const char *fmt, ...)
+{
+	va_list va;
+
+	va_start(va, fmt);
+	internal_verrorf(fmt, va);
+	va_end(va);
+	unwind(LERROR);
+}
+
+void
+internal_warningf(const char *fmt, ...)
+{
+	va_list va;
+
+	va_start(va, fmt);
+	internal_verrorf(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, "%s: ", kshname + (*kshname == '-'));
+	if (fileline && source && source->file != NULL) {
+		shf_fprintf(shl_out, "%s[%d]: ", source->file,
+		    source->errline > 0 ? 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);
+}
+
+struct shf shf_iob[3];
+
+void
+initio(void)
+{
+	shf_fdopen(1, SHF_WR, shl_stdout);	/* force buffer allocation */
+	shf_fdopen(2, SHF_WR, shl_out);
+	shf_fdopen(2, SHF_WR, shl_spare);	/* force buffer allocation */
+	initio_done = 1;
+}
+
+/* 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("too many files open in shell");
+
+#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.
+ */
+short
+savefd(int fd)
+{
+	int nfd = fd;
+
+	if (fd < FDBASE && (nfd = fcntl(fd, F_DUPFD, FDBASE)) < 0 &&
+	    errno == EBADF)
+		return (-1);
+	if (nfd < 0 || nfd > SHRT_MAX)
+		errorf("too many files open in shell");
+	fcntl(nfd, F_SETFD, FD_CLOEXEC);
+	return ((short)nfd);
+}
+
+void
+restfd(int fd, int ofd)
+{
+	if (fd == 2)
+		shf_flush(&shf_iob[fd]);
+	if (ofd < 0)		/* original fd closed */
+		close(fd);
+	else if (fd != ofd) {
+		ksh_dup2(ofd, fd, true); /* XXX: what to do if this fails? */
+		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]);
+}
+
+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] == 'p' && !name[1])
+		return (coproc_getfd(mode, emsgp));
+	for (fd = 0; ksh_isdigit(*name); ++name)
+		fd = (fd * 10) + *name - '0';
+	if (*name || fd >= FDBASE) {
+		if (emsgp)
+			*emsgp = "illegal file descriptor name";
+		return (-1);
+	}
+	if ((fl = fcntl(fd, 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)
+{
+	struct temp *tp;
+	int len;
+	int fd;
+	char *pathname;
+	const char *dir;
+
+	dir = tmpdir ? tmpdir : MKSH_DEFAULT_TMPDIR;
+#if HAVE_MKSTEMP
+	len = strlen(dir) + 6 + 10 + 1;
+#else
+	pathname = tempnam(dir, "mksh.");
+	len = ((pathname == NULL) ? 0 : strlen(pathname)) + 1;
+#endif
+	tp = alloc(sizeof(struct temp) + len, ap);
+	tp->name = (char *)&tp[1];
+#if !HAVE_MKSTEMP
+	if (pathname == NULL)
+		tp->name[0] = '\0';
+	else {
+		memcpy(tp->name, pathname, len);
+		free(pathname);
+	}
+#endif
+	pathname = tp->name;
+	tp->shf = NULL;
+	tp->type = type;
+#if HAVE_MKSTEMP
+	shf_snprintf(pathname, len, "%s/mksh.XXXXXXXXXX", dir);
+	if ((fd = mkstemp(pathname)) >= 0)
+#else
+	if (tp->name[0] && (fd = open(tp->name, O_CREAT | O_RDWR, 0600)) >= 0)
+#endif
+		tp->shf = shf_fdopen(fd, SHF_WR, NULL);
+	tp->pid = procpid;
+
+	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_TBLS	8	/* initial table size (power of 2) */
+#define PERTURB_SHIFT	5	/* see Python 2.5.4 Objects/dictobject.c */
+
+static void texpand(struct table *, size_t);
+static int tnamecmp(const void *, const void *);
+static struct tbl *ktscan(struct table *, const char *, uint32_t,
+    struct tbl ***);
+
+static void
+texpand(struct table *tp, size_t nsize)
+{
+	size_t i, j, osize = tp->size, perturb;
+	struct tbl *tblp, **pp;
+	struct tbl **ntblp, **otblp = tp->tbls;
+
+	ntblp = alloc(nsize * sizeof(struct tbl *), tp->areap);
+	for (i = 0; i < nsize; i++)
+		ntblp[i] = NULL;
+	tp->size = nsize;
+	tp->nfree = (nsize * 4) / 5;	/* table can get 80% full */
+	tp->tbls = ntblp;
+	if (otblp == NULL)
+		return;
+	nsize--;			/* from here on nsize := mask */
+	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) & nsize;
+				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 & nsize];
+				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(struct table *tp, Area *ap, size_t tsize)
+{
+	tp->areap = ap;
+	tp->tbls = NULL;
+	tp->size = tp->nfree = 0;
+	if (tsize)
+		texpand(tp, tsize);
+}
+
+/* table, name (key) to search for, hash(name), rv pointer to tbl ptr */
+static 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 = tp->size - 1;
+	/* search for hash table slot matching name */
+	j = (perturb = h) & mask;
+	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 search for, hash(n) */
+struct tbl *
+ktsearch(struct table *tp, const char *n, uint32_t h)
+{
+	return (tp->size ? ktscan(tp, n, h, NULL) : NULL);
+}
+
+/* table, name (key) to enter, hash(n) */
+struct tbl *
+ktenter(struct table *tp, const char *n, uint32_t h)
+{
+	struct tbl **pp, *p;
+	int len;
+
+	if (tp->size == 0)
+		texpand(tp, INIT_TBLS);
+ Search:
+	if ((p = ktscan(tp, n, h, &pp)))
+		return (p);
+
+	if (tp->nfree <= 0) {
+		/* too full */
+		texpand(tp, 2 * tp->size);
+		goto Search;
+	}
+
+	/* create new tbl entry */
+	len = strlen(n) + 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 = tp->size;
+	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 (strcmp(a->name, b->name));
+}
+
+struct tbl **
+ktsort(struct table *tp)
+{
+	size_t i;
+	struct tbl **p, **sp, **dp;
+
+	p = alloc((tp->size + 1) * sizeof(struct tbl *), ATEMP);
+	sp = tp->tbls;		/* source */
+	dp = p;			/* dest */
+	i = (size_t)tp->size;
+	while (i--)
+		if ((*dp = *sp++) != NULL && (((*dp)->flag & DEFINED) ||
+		    ((*dp)->flag & ARRAY)))
+			dp++;
+	qsort(p, (i = dp - p), sizeof(void *), 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