Exemplo n.º 1
0
/*
 * Parse command line and set command arguments. Returns the index of
 * non-option arguments, -1 if there is an error.
 */
int
parse_args(const char **argv,
    /* OF_CMDLINE or OF_SET */
    int what,
    bool *setargsp)
{
	static const char cmd_opts[] =
#define SHFLAGS_NOT_SET
#define SHFLAGS_OPTCS
#include "sh_flags.gen"
#undef SHFLAGS_NOT_SET
	    ;
	static const char set_opts[] =
#define SHFLAGS_NOT_CMD
#define SHFLAGS_OPTCS
#include "sh_flags.gen"
#undef SHFLAGS_NOT_CMD
	    ;
	bool set;
	const char *opts;
	const char *array = NULL;
	Getopt go;
	size_t i;
	int optc, arrayset = 0;
	bool sortargs = false;
	bool fcompatseen = false;

	if (what == OF_CMDLINE) {
		const char *p = argv[0], *q;
		/*
		 * Set FLOGIN before parsing options so user can clear
		 * flag using +l.
		 */
		if (*p != '-')
			for (q = p; *q; )
				if (*q++ == '/')
					p = q;
		Flag(FLOGIN) = (*p == '-');
		opts = cmd_opts;
	} else if (what == OF_FIRSTTIME) {
		opts = cmd_opts;
	} else
		opts = set_opts;
	ksh_getopt_reset(&go, GF_ERROR|GF_PLUSOPT);
	while ((optc = ksh_getopt(argv, &go, opts)) != -1) {
		set = tobool(!(go.info & GI_PLUS));
		switch (optc) {
		case 'A':
			if (what == OF_FIRSTTIME)
				break;
			arrayset = set ? 1 : -1;
			array = go.optarg;
			break;

		case 'o':
			if (what == OF_FIRSTTIME)
				break;
			if (go.optarg == NULL) {
				/*
				 * lone -o: print options
				 *
				 * Note that on the command line, -o requires
				 * an option (ie, can't get here if what is
				 * OF_CMDLINE).
				 */
				printoptions(set);
				break;
			}
			i = option(go.optarg);
			if ((i == FPOSIX || i == FSH) && set && !fcompatseen) {
				/*
				 * If running 'set -o posix' or
				 * 'set -o sh', turn off the other;
				 * if running 'set -o posix -o sh'
				 * allow both to be set though.
				 */
				Flag(FPOSIX) = 0;
				Flag(FSH) = 0;
				fcompatseen = true;
			}
			if ((i != (size_t)-1) && (set ? 1U : 0U) == Flag(i))
				/*
				 * Don't check the context if the flag
				 * isn't changing - makes "set -o interactive"
				 * work if you're already interactive. Needed
				 * if the output of "set +o" is to be used.
				 */
				;
			else if ((i != (size_t)-1) && (OFF(i) & what))
				change_flag((enum sh_flag)i, what, set);
			else {
				bi_errorf("%s: %s", go.optarg, "bad option");
				return (-1);
			}
			break;

#ifdef KSH_CHVT_FLAG
		case 'T':
			if (what != OF_FIRSTTIME)
				break;
#ifndef KSH_CHVT_CODE
			errorf("no TIOCSCTTY ioctl");
#else
			change_flag(FTALKING, OF_CMDLINE, true);
			chvt(&go);
			break;
#endif
#endif

		case '?':
			return (-1);

		default:
			if (what == OF_FIRSTTIME)
				break;
			/* -s: sort positional params (AT&T ksh stupidity) */
			if (what == OF_SET && optc == 's') {
				sortargs = true;
				break;
			}
			for (i = 0; i < NELEM(options); i++)
				if (optc == OFC(i) &&
				    (what & OFF(i))) {
					change_flag((enum sh_flag)i, what, set);
					break;
				}
			if (i == NELEM(options))
				internal_errorf("parse_args: '%c'", optc);
		}
	}
	if (!(go.info & GI_MINUSMINUS) && argv[go.optind] &&
	    (argv[go.optind][0] == '-' || argv[go.optind][0] == '+') &&
	    argv[go.optind][1] == '\0') {
		/* lone - clears -v and -x flags */
		if (argv[go.optind][0] == '-') {
			Flag(FVERBOSE) = 0;
			change_xtrace(0, false);
		}
		/* set skips lone - or + option */
		go.optind++;
	}
	if (setargsp)
		/* -- means set $#/$* even if there are no arguments */
		*setargsp = !arrayset && ((go.info & GI_MINUSMINUS) ||
		    argv[go.optind]);

	if (arrayset) {
		const char *ccp = NULL;

		if (*array)
			ccp = skip_varname(array, false);
		if (!ccp || !(!ccp[0] || (ccp[0] == '+' && !ccp[1]))) {
			bi_errorf("%s: %s", array, "is not an identifier");
			return (-1);
		}
	}
	if (sortargs) {
		for (i = go.optind; argv[i]; i++)
			;
		qsort(&argv[go.optind], i - go.optind, sizeof(void *),
		    xstrcmp);
	}
	if (arrayset)
		go.optind += set_array(array, tobool(arrayset > 0),
		    argv + go.optind);

	return (go.optind);
}
Exemplo n.º 2
0
/* change a Flag(*) value; takes care of special actions */
void
change_flag(enum sh_flag f, int what, bool newset)
{
	unsigned char oldval;
	unsigned char newval = (newset ? 1 : 0);

	if (f == FXTRACE) {
		change_xtrace(newval, true);
		return;
	}
	oldval = Flag(f);
	Flag(f) = newval = (newset ? 1 : 0);
#ifndef MKSH_UNEMPLOYED
	if (f == FMONITOR) {
		if (what != OF_CMDLINE && newval != oldval)
			j_change();
	} else
#endif
#ifndef MKSH_NO_CMDLINE_EDITING
	  if ((
#if !MKSH_S_NOVI
	    f == FVI ||
#endif
	    f == FEMACS || f == FGMACS) && newval) {
#if !MKSH_S_NOVI
		Flag(FVI) =
#endif
		    Flag(FEMACS) = Flag(FGMACS) = 0;
		Flag(f) = newval;
	} else
#endif
	  if (f == FPRIVILEGED && oldval && !newval) {
		/* Turning off -p? */

		/*XXX this can probably be optimised */
		kshegid = kshgid = getgid();
		ksheuid = kshuid = getuid();
#if HAVE_SETRESUGID
		DO_SETUID(setresgid, (kshegid, kshegid, kshegid));
#if HAVE_SETGROUPS
		/* setgroups doesn't EAGAIN on Linux */
		setgroups(1, &kshegid);
#endif
		DO_SETUID(setresuid, (ksheuid, ksheuid, ksheuid));
#else /* !HAVE_SETRESUGID */
		/* setgid, setegid, seteuid don't EAGAIN on Linux */
		setgid(kshegid);
#ifndef MKSH__NO_SETEUGID
		setegid(kshegid);
#endif
		DO_SETUID(setuid, (ksheuid));
#ifndef MKSH__NO_SETEUGID
		seteuid(ksheuid);
#endif
#endif /* !HAVE_SETRESUGID */
	} else if ((f == FPOSIX || f == FSH) && newval) {
		/* Turning on -o posix or -o sh? */
		Flag(FBRACEEXPAND) = 0;
	} else if (f == FTALKING) {
		/* Changing interactive flag? */
		if ((what == OF_CMDLINE || what == OF_SET) && procpid == kshpid)
			Flag(FTALKING_I) = newval;
	}
}
Exemplo n.º 3
0
/*
 * set up redirection, saving old fds in e->savefd
 */
static int
iosetup(struct ioword *iop, struct tbl *tp)
{
	int u = -1;
	char *cp = iop->name;
	int iotype = iop->flag & IOTYPE;
	bool do_open = true, do_close = false;
	int flags = 0;
	struct ioword iotmp;
	struct stat statb;

	if (iotype != IOHERE)
		cp = evalonestr(cp, DOTILDE|(Flag(FTALKING_I) ? DOGLOB : 0));

	/* Used for tracing and error messages to print expanded cp */
	iotmp = *iop;
	iotmp.name = (iotype == IOHERE) ? NULL : cp;
	iotmp.flag |= IONAMEXP;

	if (Flag(FXTRACE)) {
		change_xtrace(2, false);
		fptreef(shl_xtrace, 0, "%R", &iotmp);
		change_xtrace(1, false);
	}

	switch (iotype) {
	case IOREAD:
		flags = O_RDONLY;
		break;

	case IOCAT:
		flags = O_WRONLY | O_APPEND | O_CREAT;
		break;

	case IOWRITE:
		flags = O_WRONLY | O_CREAT | O_TRUNC;
		/*
		 * The stat() is here to allow redirections to
		 * things like /dev/null without error.
		 */
		if (Flag(FNOCLOBBER) && !(iop->flag & IOCLOB) &&
		    (stat(cp, &statb) < 0 || S_ISREG(statb.st_mode)))
			flags |= O_EXCL;
		break;

	case IORDWR:
		flags = O_RDWR | O_CREAT;
		break;

	case IOHERE:
		do_open = false;
		/* herein() returns -2 if error has been printed */
		u = herein(iop, NULL);
		/* cp may have wrong name */
		break;

	case IODUP: {
		const char *emsg;

		do_open = false;
		if (*cp == '-' && !cp[1]) {
			/* prevent error return below */
			u = 1009;
			do_close = true;
		} else if ((u = check_fd(cp,
		    X_OK | ((iop->flag & IORDUP) ? R_OK : W_OK),
		    &emsg)) < 0) {
			char *sp;

			warningf(true, "%s: %s",
			    (sp = snptreef(NULL, 32, "%R", &iotmp)), emsg);
			afree(sp, ATEMP);
			return (-1);
		}
		if (u == iop->unit)
			/* "dup from" == "dup to" */
			return (0);
		break;
	    }
	}

	if (do_open) {
		if (Flag(FRESTRICTED) && (flags & O_CREAT)) {
			warningf(true, "%s: %s", cp, "restricted");
			return (-1);
		}
		u = open(cp, flags | O_BINARY, 0666);
	}
	if (u < 0) {
		/* herein() may already have printed message */
		if (u == -1) {
			u = errno;
			warningf(true, "can't %s %s: %s",
			    iotype == IODUP ? "dup" :
			    (iotype == IOREAD || iotype == IOHERE) ?
			    "open" : "create", cp, cstrerror(u));
		}
		return (-1);
	}
	/* Do not save if it has already been redirected (i.e. "cat >x >y"). */
	if (e->savefd[iop->unit] == 0) {
		/* If these are the same, it means unit was previously closed */
		if (u == iop->unit)
			e->savefd[iop->unit] = -1;
		else
			/*
			 * c_exec() assumes e->savefd[fd] set for any
			 * redirections. Ask savefd() not to close iop->unit;
			 * this allows error messages to be seen if iop->unit
			 * is 2; also means we can't lose the fd (eg, both
			 * dup2 below and dup2 in restfd() failing).
			 */
			e->savefd[iop->unit] = savefd(iop->unit);
	}

	if (do_close)
		close(iop->unit);
	else if (u != iop->unit) {
		if (ksh_dup2(u, iop->unit, true) < 0) {
			int eno;
			char *sp;

			eno = errno;
			warningf(true, "%s %s %s",
			    "can't finish (dup) redirection",
			    (sp = snptreef(NULL, 32, "%R", &iotmp)),
			    cstrerror(eno));
			afree(sp, ATEMP);
			if (iotype != IODUP)
				close(u);
			return (-1);
		}
		if (iotype != IODUP)
			close(u);
		/*
		 * Touching any co-process fd in an empty exec
		 * causes the shell to close its copies
		 */
		else if (tp && tp->type == CSHELL && tp->val.f == c_exec) {
			if (iop->flag & IORDUP)
				/* possible exec <&p */
				coproc_read_close(u);
			else
				/* possible exec >&p */
				coproc_write_close(u);
		}
	}
	if (u == 2)
		/* Clear any write errors */
		shf_reopen(2, SHF_WR, shl_out);
	return (0);
}
Exemplo n.º 4
0
static int
comexec(struct op *t, struct tbl * volatile tp, const char **ap,
    volatile int flags, volatile int *xerrok)
{
	int i;
	volatile int rv = 0;
	const char *cp;
	const char **lastp;
	/* Must be static (XXX but why?) */
	static struct op texec;
	int type_flags;
	bool keepasn_ok;
	int fcflags = FC_BI|FC_FUNC|FC_PATH;
	bool bourne_function_call = false;
	struct block *l_expand, *l_assign;

	/*
	 * snag the last argument for $_ XXX not the same as AT&T ksh,
	 * which only seems to set $_ after a newline (but not in
	 * functions/dot scripts, but in interactive and script) -
	 * perhaps save last arg here and set it in shell()?.
	 */
	if (Flag(FTALKING) && *(lastp = ap)) {
		while (*++lastp)
			;
		/* setstr() can't fail here */
		setstr(typeset("_", LOCAL, 0, INTEGER, 0), *--lastp,
		    KSH_RETURN_ERROR);
	}

	/**
	 * Deal with the shell builtins builtin, exec and command since
	 * they can be followed by other commands. This must be done before
	 * we know if we should create a local block which must be done
	 * before we can do a path search (in case the assignments change
	 * PATH).
	 * Odd cases:
	 *	FOO=bar exec >/dev/null		FOO is kept but not exported
	 *	FOO=bar exec foobar		FOO is exported
	 *	FOO=bar command exec >/dev/null	FOO is neither kept nor exported
	 *	FOO=bar command			FOO is neither kept nor exported
	 *	PATH=... foobar			use new PATH in foobar search
	 */
	keepasn_ok = true;
	while (tp && tp->type == CSHELL) {
		/* undo effects of command */
		fcflags = FC_BI|FC_FUNC|FC_PATH;
		if (tp->val.f == c_builtin) {
			if ((cp = *++ap) == NULL ||
			    (!strcmp(cp, "--") && (cp = *++ap) == NULL)) {
				tp = NULL;
				break;
			}
			if ((tp = findcom(cp, FC_BI)) == NULL)
				errorf("%s: %s: %s", Tbuiltin, cp, "not a builtin");
			continue;
		} else if (tp->val.f == c_exec) {
			if (ap[1] == NULL)
				break;
			ap++;
			flags |= XEXEC;
		} else if (tp->val.f == c_command) {
			int optc, saw_p = 0;

			/*
			 * Ugly dealing with options in two places (here
			 * and in c_command(), but such is life)
			 */
			ksh_getopt_reset(&builtin_opt, 0);
			while ((optc = ksh_getopt(ap, &builtin_opt, ":p")) == 'p')
				saw_p = 1;
			if (optc != EOF)
				/* command -vV or something */
				break;
			/* don't look for functions */
			fcflags = FC_BI|FC_PATH;
			if (saw_p) {
				if (Flag(FRESTRICTED)) {
					warningf(true, "%s: %s",
					    "command -p", "restricted");
					rv = 1;
					goto Leave;
				}
				fcflags |= FC_DEFPATH;
			}
			ap += builtin_opt.optind;
			/*
			 * POSIX says special builtins lose their status
			 * if accessed using command.
			 */
			keepasn_ok = false;
			if (!ap[0]) {
				/* ensure command with no args exits with 0 */
				subst_exstat = 0;
				break;
			}
#ifndef MKSH_NO_EXTERNAL_CAT
		} else if (tp->val.f == c_cat) {
			/*
			 * if we have any flags, do not use the builtin
			 * in theory, we could allow -u, but that would
			 * mean to use ksh_getopt here and possibly ad-
			 * ded complexity and more code and isn't worth
			 * additional hassle (and the builtin must call
			 * ksh_getopt already but can't come back here)
			 */
			if (ap[1] && ap[1][0] == '-' && ap[1][1] != '\0' &&
			    /* argument, begins with -, is not - or -- */
			    (ap[1][1] != '-' || ap[1][2] != '\0'))
				/* don't look for builtins or functions */
				fcflags = FC_PATH;
			else
				/* go on, use the builtin */
				break;
#endif
		} else if (tp->val.f == c_trap) {
			t->u.evalflags &= ~DOTCOMEXEC;
			break;
		} else
			break;
		tp = findcom(ap[0], fcflags & (FC_BI|FC_FUNC));
	}
	if (t->u.evalflags & DOTCOMEXEC)
		flags |= XEXEC;
	l_expand = e->loc;
	if (keepasn_ok && (!ap[0] || (tp && (tp->flag & KEEPASN))))
		type_flags = 0;
	else {
		/* create new variable/function block */
		newblock();
		/* ksh functions don't keep assignments, POSIX functions do. */
		if (keepasn_ok && tp && tp->type == CFUNC &&
		    !(tp->flag & FKSH)) {
			bourne_function_call = true;
			type_flags = EXPORT;
		} else
			type_flags = LOCAL|LOCAL_COPY|EXPORT;
	}
	l_assign = e->loc;
	if (Flag(FEXPORT))
		type_flags |= EXPORT;
	if (Flag(FXTRACE))
		change_xtrace(2, false);
	for (i = 0; t->vars[i]; i++) {
		/* do NOT lookup in the new var/fn block just created */
		e->loc = l_expand;
		cp = evalstr(t->vars[i], DOASNTILDE | DOASNFIELD);
		e->loc = l_assign;
		if (Flag(FXTRACE)) {
			const char *ccp;

			ccp = skip_varname(cp, true);
			if (*ccp == '+')
				++ccp;
			if (*ccp == '=')
				++ccp;
			shf_write(cp, ccp - cp, shl_xtrace);
			print_value_quoted(shl_xtrace, ccp);
			shf_putc(' ', shl_xtrace);
		}
		/* but assign in there as usual */
		typeset(cp, type_flags, 0, 0, 0);
		if (bourne_function_call && !(type_flags & EXPORT))
			typeset(cp, LOCAL | LOCAL_COPY | EXPORT, 0, 0, 0);
	}

	if (Flag(FXTRACE)) {
		change_xtrace(2, false);
		if (ap[rv = 0]) {
 xtrace_ap_loop:
			print_value_quoted(shl_xtrace, ap[rv]);
			if (ap[++rv]) {
				shf_putc(' ', shl_xtrace);
				goto xtrace_ap_loop;
			}
		}
		change_xtrace(1, false);
	}

	if ((cp = *ap) == NULL) {
		rv = subst_exstat;
		goto Leave;
	} else if (!tp) {
		if (Flag(FRESTRICTED) && vstrchr(cp, '/')) {
			warningf(true, "%s: %s", cp, "restricted");
			rv = 1;
			goto Leave;
		}
		tp = findcom(cp, fcflags);
	}

	switch (tp->type) {

	/* shell built-in */
	case CSHELL:
		rv = call_builtin(tp, (const char **)ap, null);
		if (!keepasn_ok && tp->val.f == c_shift) {
			l_expand->argc = l_assign->argc;
			l_expand->argv = l_assign->argv;
		}
		break;

	/* function call */
	case CFUNC: {
		volatile unsigned char old_xflag;
		volatile uint32_t old_inuse;
		const char * volatile old_kshname;

		if (!(tp->flag & ISSET)) {
			struct tbl *ftp;

			if (!tp->u.fpath) {
				rv = (tp->u2.errnov == ENOENT) ? 127 : 126;
				warningf(true, "%s: %s %s: %s", cp,
				    "can't find", "function definition file",
				    cstrerror(tp->u2.errnov));
				break;
			}
			if (include(tp->u.fpath, 0, NULL, false) < 0) {
				warningf(true, "%s: %s %s %s: %s", cp,
				    "can't open", "function definition file",
				    tp->u.fpath, cstrerror(errno));
				rv = 127;
				break;
			}
			if (!(ftp = findfunc(cp, hash(cp), false)) ||
			    !(ftp->flag & ISSET)) {
				warningf(true, "%s: %s %s", cp,
				    "function not defined by", tp->u.fpath);
				rv = 127;
				break;
			}
			tp = ftp;
		}

		/*
		 * ksh functions set $0 to function name, POSIX
		 * functions leave $0 unchanged.
		 */
		old_kshname = kshname;
		if (tp->flag & FKSH)
			kshname = ap[0];
		else
			ap[0] = kshname;
		e->loc->argv = ap;
		for (i = 0; *ap++ != NULL; i++)
			;
		e->loc->argc = i - 1;
		/*
		 * ksh-style functions handle getopts sanely,
		 * Bourne/POSIX functions are insane...
		 */
		if (tp->flag & FKSH) {
			e->loc->flags |= BF_DOGETOPTS;
			e->loc->getopts_state = user_opt;
			getopts_reset(1);
		}

		old_xflag = Flag(FXTRACE) ? 1 : 0;
		change_xtrace((Flag(FXTRACEREC) ? old_xflag : 0) |
		    ((tp->flag & TRACE) ? 1 : 0), false);
		old_inuse = tp->flag & FINUSE;
		tp->flag |= FINUSE;

		e->type = E_FUNC;
		if (!(i = kshsetjmp(e->jbuf))) {
			execute(tp->val.t, flags & XERROK, NULL);
			i = LRETURN;
		}

		kshname = old_kshname;
		change_xtrace(old_xflag, false);
		tp->flag = (tp->flag & ~FINUSE) | old_inuse;

		/*
		 * Were we deleted while executing? If so, free the
		 * execution tree. TODO: Unfortunately, the table entry
		 * is never re-used until the lookup table is expanded.
		 */
		if ((tp->flag & (FDELETE|FINUSE)) == FDELETE) {
			if (tp->flag & ALLOC) {
				tp->flag &= ~ALLOC;
				tfree(tp->val.t, tp->areap);
			}
			tp->flag = 0;
		}
		switch (i) {
		case LRETURN:
		case LERROR:
			rv = exstat & 0xFF;
			break;
		case LINTR:
		case LEXIT:
		case LLEAVE:
		case LSHELL:
			quitenv(NULL);
			unwind(i);
			/* NOTREACHED */
		default:
			quitenv(NULL);
			internal_errorf("%s %d", "CFUNC", i);
		}
		break;
	}

	/* executable command */
	case CEXEC:
	/* tracked alias */
	case CTALIAS:
		if (!(tp->flag&ISSET)) {
			if (tp->u2.errnov == ENOENT) {
				rv = 127;
				warningf(true, "%s: %s", cp, "not found");
			} else {
				rv = 126;
				warningf(true, "%s: %s: %s", cp, "can't execute",
				    cstrerror(tp->u2.errnov));
			}
			break;
		}

		/* set $_ to programme's full path */
		/* setstr() can't fail here */
		setstr(typeset("_", LOCAL | EXPORT, 0, INTEGER, 0),
		    tp->val.s, KSH_RETURN_ERROR);

		if (flags&XEXEC) {
			j_exit();
			if (!(flags&XBGND)
#ifndef MKSH_UNEMPLOYED
			    || Flag(FMONITOR)
#endif
			    ) {
				setexecsig(&sigtraps[SIGINT], SS_RESTORE_ORIG);
				setexecsig(&sigtraps[SIGQUIT], SS_RESTORE_ORIG);
			}
		}

		/* to fork we set up a TEXEC node and call execute */
		texec.type = TEXEC;
		/* for tprint */
		texec.left = t;
		texec.str = tp->val.s;
		texec.args = ap;
		rv = exchild(&texec, flags, xerrok, -1);
		break;
	}
 Leave:
	if (flags & XEXEC) {
		exstat = rv & 0xFF;
		unwind(LLEAVE);
	}
	return (rv);
}
Exemplo n.º 5
0
static int
comexec(struct op *t, struct tbl * volatile tp, const char **ap,
    volatile int flags, volatile int *xerrok)
{
	int i;
	volatile int rv = 0;
	const char *cp;
	const char **lastp;
	/* Must be static (XXX but why?) */
	static struct op texec;
	int type_flags;
	bool resetspec;
	int fcflags = FC_BI|FC_FUNC|FC_PATH;
	struct block *l_expand, *l_assign;
	int optc;
	const char *exec_argv0 = NULL;
	bool exec_clrenv = false;

	/* snag the last argument for $_ */
	if (Flag(FTALKING) && *(lastp = ap)) {
		/*
		 * XXX not the same as AT&T ksh, which only seems to set $_
		 * after a newline (but not in functions/dot scripts, but in
		 * interactive and script) - perhaps save last arg here and
		 * set it in shell()?.
		 */
		while (*++lastp)
			;
		/* setstr() can't fail here */
		setstr(typeset("_", LOCAL, 0, INTEGER, 0), *--lastp,
		    KSH_RETURN_ERROR);
	}

	/**
	 * Deal with the shell builtins builtin, exec and command since
	 * they can be followed by other commands. This must be done before
	 * we know if we should create a local block which must be done
	 * before we can do a path search (in case the assignments change
	 * PATH).
	 * Odd cases:
	 *	FOO=bar exec >/dev/null		FOO is kept but not exported
	 *	FOO=bar exec foobar		FOO is exported
	 *	FOO=bar command exec >/dev/null	FOO is neither kept nor exported
	 *	FOO=bar command			FOO is neither kept nor exported
	 *	PATH=... foobar			use new PATH in foobar search
	 */
	resetspec = false;
	while (tp && tp->type == CSHELL) {
		/* undo effects of command */
		fcflags = FC_BI|FC_FUNC|FC_PATH;
		if (tp->val.f == c_builtin) {
			if ((cp = *++ap) == NULL ||
			    (!strcmp(cp, "--") && (cp = *++ap) == NULL)) {
				tp = NULL;
				break;
			}
			if ((tp = findcom(cp, FC_BI)) == NULL)
				errorf("%s: %s: %s", Tbuiltin, cp, "not a builtin");
			if (tp->type == CSHELL && (tp->val.f == c_cat
#ifdef MKSH_PRINTF_BUILTIN
			    || tp->val.f == c_printf
#endif
			    ))
				break;
			continue;
		} else if (tp->val.f == c_exec) {
			if (ap[1] == NULL)
				break;
			ksh_getopt_reset(&builtin_opt, GF_ERROR);
			while ((optc = ksh_getopt(ap, &builtin_opt, "a:c")) != -1)
				switch (optc) {
				case 'a':
					exec_argv0 = builtin_opt.optarg;
					break;
				case 'c':
					exec_clrenv = true;
					/* ensure we can actually do this */
					resetspec = true;
					break;
				default:
					rv = 2;
					goto Leave;
				}
			ap += builtin_opt.optind;
			flags |= XEXEC;
		} else if (tp->val.f == c_command) {
			bool saw_p = false;

			/*
			 * Ugly dealing with options in two places (here
			 * and in c_command(), but such is life)
			 */
			ksh_getopt_reset(&builtin_opt, 0);
			while ((optc = ksh_getopt(ap, &builtin_opt, ":p")) == 'p')
				saw_p = true;
			if (optc != -1)
				/* command -vV or something */
				break;
			/* don't look for functions */
			fcflags = FC_BI|FC_PATH;
			if (saw_p) {
				if (Flag(FRESTRICTED)) {
					warningf(true, "%s: %s",
					    "command -p", "restricted");
					rv = 1;
					goto Leave;
				}
				fcflags |= FC_DEFPATH;
			}
			ap += builtin_opt.optind;
			/*
			 * POSIX says special builtins lose their status
			 * if accessed using command.
			 */
			resetspec = true;
			if (!ap[0]) {
				/* ensure command with no args exits with 0 */
				subst_exstat = 0;
				break;
			}
		} else if (tp->val.f == c_cat) {
			/* if we have any flags, do not use the builtin */
			if (ap[1] && ap[1][0] == '-' && ap[1][1] != '\0' &&
			    /* argument, begins with -, is not - or -- */
			    (ap[1][1] != '-' || ap[1][2] != '\0')) {
				struct tbl *ext_cat;

				ext_cat = findcom(Tcat, FC_PATH | FC_FUNC);
				if (ext_cat && (ext_cat->type != CTALIAS ||
				    (ext_cat->flag & ISSET)))
					tp = ext_cat;
			}
			break;
#ifdef MKSH_PRINTF_BUILTIN
		} else if (tp->val.f == c_printf) {
			struct tbl *ext_printf;

			ext_printf = findcom(Tprintf, FC_PATH | FC_FUNC);
			if (ext_printf && (ext_printf->type != CTALIAS ||
			    (ext_printf->flag & ISSET)))
				tp = ext_printf;
			break;
#endif
		} else if (tp->val.f == c_trap) {
			t->u.evalflags &= ~DOTCOMEXEC;
			break;
		} else
			break;
		tp = findcom(ap[0], fcflags & (FC_BI|FC_FUNC));
	}
	if (t->u.evalflags & DOTCOMEXEC)
		flags |= XEXEC;
	l_expand = e->loc;
	if (!resetspec && (!ap[0] || (tp && (tp->flag & KEEPASN))))
		type_flags = 0;
	else {
		/* create new variable/function block */
		newblock();
		/* ksh functions don't keep assignments, POSIX functions do. */
		if (!resetspec && tp && tp->type == CFUNC &&
		    !(tp->flag & FKSH))
			type_flags = EXPORT;
		else
			type_flags = LOCAL|LOCAL_COPY|EXPORT;
	}
	l_assign = e->loc;
	if (exec_clrenv)
		l_assign->flags |= BF_STOPENV;
	if (Flag(FEXPORT))
		type_flags |= EXPORT;
	if (Flag(FXTRACE))
		change_xtrace(2, false);
	for (i = 0; t->vars[i]; i++) {
		/* do NOT lookup in the new var/fn block just created */
		e->loc = l_expand;
		cp = evalstr(t->vars[i], DOASNTILDE | DOSCALAR);
		e->loc = l_assign;
		if (Flag(FXTRACE)) {
			const char *ccp;

			ccp = skip_varname(cp, true);
			if (*ccp == '+')
				++ccp;
			if (*ccp == '=')
				++ccp;
			shf_write(cp, ccp - cp, shl_xtrace);
			print_value_quoted(shl_xtrace, ccp);
			shf_putc(' ', shl_xtrace);
		}
		/* but assign in there as usual */
		typeset(cp, type_flags, 0, 0, 0);
	}

	if (Flag(FXTRACE)) {
		change_xtrace(2, false);
		if (ap[rv = 0]) {
 xtrace_ap_loop:
			print_value_quoted(shl_xtrace, ap[rv]);
			if (ap[++rv]) {
				shf_putc(' ', shl_xtrace);
				goto xtrace_ap_loop;
			}
		}
		change_xtrace(1, false);
	}

	if ((cp = *ap) == NULL) {
		rv = subst_exstat;
		goto Leave;
	} else if (!tp) {
		if (Flag(FRESTRICTED) && vstrchr(cp, '/')) {
			warningf(true, "%s: %s", cp, "restricted");
			rv = 1;
			goto Leave;
		}
		tp = findcom(cp, fcflags);
	}

	switch (tp->type) {

	/* shell built-in */
	case CSHELL:
 do_call_builtin:
		rv = call_builtin(tp, (const char **)ap, null, resetspec);
		if (resetspec && tp->val.f == c_shift) {
			l_expand->argc = l_assign->argc;
			l_expand->argv = l_assign->argv;
		}
		break;

	/* function call */
	case CFUNC: {
		volatile uint32_t old_inuse;
		const char * volatile old_kshname;
		volatile uint8_t old_flags[FNFLAGS];

		if (!(tp->flag & ISSET)) {
			struct tbl *ftp;

			if (!tp->u.fpath) {
				rv = (tp->u2.errnov == ENOENT) ? 127 : 126;
				warningf(true, "%s: %s %s: %s", cp,
				    "can't find", "function definition file",
				    cstrerror(tp->u2.errnov));
				break;
			}
			if (include(tp->u.fpath, 0, NULL, false) < 0) {
				if (!strcmp(cp, Tcat)) {
 no_cat_in_FPATH:
					tp = findcom(Tcat, FC_BI);
					goto do_call_builtin;
				}
#ifdef MKSH_PRINTF_BUILTIN
				if (!strcmp(cp, Tprintf)) {
 no_printf_in_FPATH:
					tp = findcom(Tprintf, FC_BI);
					goto do_call_builtin;
				}
#endif
				warningf(true, "%s: %s %s %s: %s", cp,
				    "can't open", "function definition file",
				    tp->u.fpath, cstrerror(errno));
				rv = 127;
				break;
			}
			if (!(ftp = findfunc(cp, hash(cp), false)) ||
			    !(ftp->flag & ISSET)) {
				if (!strcmp(cp, Tcat))
					goto no_cat_in_FPATH;
#ifdef MKSH_PRINTF_BUILTIN
				if (!strcmp(cp, Tprintf))
					goto no_printf_in_FPATH;
#endif
				warningf(true, "%s: %s %s", cp,
				    "function not defined by", tp->u.fpath);
				rv = 127;
				break;
			}
			tp = ftp;
		}

		/*
		 * ksh functions set $0 to function name, POSIX
		 * functions leave $0 unchanged.
		 */
		old_kshname = kshname;
		if (tp->flag & FKSH)
			kshname = ap[0];
		else
			ap[0] = kshname;
		e->loc->argv = ap;
		for (i = 0; *ap++ != NULL; i++)
			;
		e->loc->argc = i - 1;
		/*
		 * ksh-style functions handle getopts sanely,
		 * Bourne/POSIX functions are insane...
		 */
		if (tp->flag & FKSH) {
			e->loc->flags |= BF_DOGETOPTS;
			e->loc->getopts_state = user_opt;
			getopts_reset(1);
		}

		for (type_flags = 0; type_flags < FNFLAGS; ++type_flags)
			old_flags[type_flags] = shell_flags[type_flags];
		change_xtrace((Flag(FXTRACEREC) ? Flag(FXTRACE) : 0) |
		    ((tp->flag & TRACE) ? 1 : 0), false);
		old_inuse = tp->flag & FINUSE;
		tp->flag |= FINUSE;

		e->type = E_FUNC;
		if (!(i = kshsetjmp(e->jbuf))) {
			execute(tp->val.t, flags & XERROK, NULL);
			i = LRETURN;
		}

		kshname = old_kshname;
		change_xtrace(old_flags[(int)FXTRACE], false);
#ifndef MKSH_LEGACY_MODE
		if (tp->flag & FKSH) {
			/* Korn style functions restore Flags on return */
			old_flags[(int)FXTRACE] = Flag(FXTRACE);
			for (type_flags = 0; type_flags < FNFLAGS; ++type_flags)
				shell_flags[type_flags] = old_flags[type_flags];
		}
#endif
		tp->flag = (tp->flag & ~FINUSE) | old_inuse;

		/*
		 * Were we deleted while executing? If so, free the
		 * execution tree.
		 */
		if ((tp->flag & (FDELETE|FINUSE)) == FDELETE) {
			if (tp->flag & ALLOC) {
				tp->flag &= ~ALLOC;
				tfree(tp->val.t, tp->areap);
			}
			tp->flag = 0;
		}
		switch (i) {
		case LRETURN:
		case LERROR:
			rv = exstat & 0xFF;
			break;
		case LINTR:
		case LEXIT:
		case LLEAVE:
		case LSHELL:
			quitenv(NULL);
			unwind(i);
			/* NOTREACHED */
		default:
			quitenv(NULL);
			internal_errorf("%s %d", "CFUNC", i);
		}
		break;
	}

	/* executable command */
	case CEXEC:
	/* tracked alias */
	case CTALIAS:
		if (!(tp->flag&ISSET)) {
			if (tp->u2.errnov == ENOENT) {
				rv = 127;
				warningf(true, "%s: %s", cp, "not found");
			} else {
				rv = 126;
				warningf(true, "%s: %s: %s", cp, "can't execute",
				    cstrerror(tp->u2.errnov));
			}
			break;
		}

		/* set $_ to program's full path */
		/* setstr() can't fail here */
		setstr(typeset("_", LOCAL | EXPORT, 0, INTEGER, 0),
		    tp->val.s, KSH_RETURN_ERROR);

		/* to fork, we set up a TEXEC node and call execute */
		texec.type = TEXEC;
		/* for vistree/dumptree */
		texec.left = t;
		texec.str = tp->val.s;
		texec.args = ap;

		/* in this case we do not fork, of course */
		if (flags & XEXEC) {
			if (exec_argv0)
				texec.args[0] = exec_argv0;
			j_exit();
			if (!(flags & XBGND)
#ifndef MKSH_UNEMPLOYED
			    || Flag(FMONITOR)
#endif
			    ) {
				setexecsig(&sigtraps[SIGINT], SS_RESTORE_ORIG);
				setexecsig(&sigtraps[SIGQUIT], SS_RESTORE_ORIG);
			}
		}

		rv = exchild(&texec, flags, xerrok, -1);
		break;
	}
 Leave:
	if (flags & XEXEC) {
		exstat = rv & 0xFF;
		unwind(LLEAVE);
	}
	return (rv);
}