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-rw-r--r--bin/1sh/var.c982
1 files changed, 982 insertions, 0 deletions
diff --git a/bin/1sh/var.c b/bin/1sh/var.c
new file mode 100644
index 00000000..83e48732
--- /dev/null
+++ b/bin/1sh/var.c
@@ -0,0 +1,982 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 5/4/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: releng/12.0/bin/sh/var.c 329221 2018-02-13 16:48:57Z bdrewery $");
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <paths.h>
+
+/*
+ * Shell variables.
+ */
+
+#include <locale.h>
+#include <langinfo.h>
+
+#include "shell.h"
+#include "output.h"
+#include "expand.h"
+#include "nodes.h"	/* for other headers */
+#include "eval.h"	/* defines cmdenviron */
+#include "exec.h"
+#include "syntax.h"
+#include "options.h"
+#include "mail.h"
+#include "var.h"
+#include "memalloc.h"
+#include "error.h"
+#include "mystring.h"
+#include "parser.h"
+#include "builtins.h"
+#ifndef NO_HISTORY
+#include "myhistedit.h"
+#endif
+
+
+#ifndef VTABSIZE
+#define VTABSIZE 39
+#endif
+
+
+struct varinit {
+	struct var *var;
+	int flags;
+	const char *text;
+	void (*func)(const char *);
+};
+
+
+#ifndef NO_HISTORY
+struct var vhistfile;
+struct var vhistsize;
+struct var vpslit;
+struct var vterm;
+#endif
+struct var venv;
+struct var vifs;
+struct var vmail;
+struct var vmpath;
+struct var vpath;
+struct var vps0;
+struct var vps1;
+struct var vps2;
+struct var vps4;
+struct var vrps1;
+struct var vrps2;
+static struct var voptind;
+struct var vdisvfork;
+
+struct localvar *localvars;
+int forcelocal;
+
+#define XDG_CONFIG_HOME "${XDG_CONFIG_HOME:-${HOME}/.config}"
+#define XDG_DATA_HOME "${XDG_DATA_HOME:-${HOME}/.local/share}"
+
+static const struct varinit varinit[] = {
+	{ &venv, 0, "ENV=" XDG_CONFIG_HOME "/1sh/env.sh",
+	  NULL },
+#ifndef NO_HISTORY
+	{ &vhistfile, 0, "HISTFILE=" XDG_DATA_HOME "/1sh/history",
+	  sethistfile },
+	{ &vhistsize,	VUNSET,				"HISTSIZE=",
+	  sethistsize },
+#endif
+	{ &vifs,	0,				"IFS= \t\n",
+	  NULL },
+	{ &vmail,	VUNSET,				"MAIL=",
+	  NULL },
+	{ &vmpath,	VUNSET,				"MAILPATH=",
+	  NULL },
+	{ &vpath,	0,				"PATH=" _PATH_DEFPATH,
+	  changepath },
+	{ &vps0,	VUNSET,				"PS0=",
+	  NULL },
+	{ &vps1,	0,				"PS1=\\$ ",
+	  NULL },
+	{ &vps2,	0,				"PS2=> ",
+	  NULL },
+	{ &vps4,	0,				"PS4=+ ",
+	  NULL },
+	{ &vrps1,	VUNSET,				"RPS1=",
+	  NULL },
+	{ &vrps2,	VUNSET,				"RPS2=",
+	  NULL },
+#ifndef NO_HISTORY
+	{ &vpslit,	VUNSET,				"PSlit=",
+	  setpslit },
+	{ &vterm,	VUNSET,				"TERM=",
+	  setterm },
+#endif
+	{ &voptind,	0,				"OPTIND=1",
+	  getoptsreset },
+	{ &vdisvfork,	VUNSET,				"SH_DISABLE_VFORK=",
+	  NULL },
+	{ NULL,	0,				NULL,
+	  NULL }
+};
+
+static struct var *vartab[VTABSIZE];
+
+static const char *const locale_names[7] = {
+	"LC_COLLATE", "LC_CTYPE", "LC_MONETARY",
+	"LC_NUMERIC", "LC_TIME", "LC_MESSAGES", NULL
+};
+static const int locale_categories[7] = {
+	LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME, LC_MESSAGES, 0
+};
+
+static int varequal(const char *, const char *);
+static struct var *find_var(const char *, struct var ***, int *);
+static int localevar(const char *);
+static void setvareq_const(const char *s, int flags);
+
+extern char **environ;
+
+/*
+ * This routine initializes the builtin variables and imports the environment.
+ * It is called when the shell is initialized.
+ */
+
+void
+initvar(void)
+{
+	char ppid[20];
+	const struct varinit *ip;
+	struct var *vp;
+	struct var **vpp;
+	char **envp;
+
+	for (ip = varinit ; (vp = ip->var) != NULL ; ip++) {
+		if (find_var(ip->text, &vpp, &vp->name_len) != NULL)
+			continue;
+		vp->next = *vpp;
+		*vpp = vp;
+		vp->text = __DECONST(char *, ip->text);
+		vp->flags = ip->flags | VSTRFIXED | VTEXTFIXED;
+		vp->func = ip->func;
+	}
+	fmtstr(ppid, sizeof(ppid), "%d", (int)getppid());
+	setvarsafe("PPID", ppid, 0);
+	for (envp = environ ; *envp ; envp++) {
+		if (strchr(*envp, '=')) {
+			setvareq(*envp, VEXPORT|VTEXTFIXED);
+		}
+	}
+	setvareq_const("OPTIND=1", 0);
+	setvareq_const("IFS= \t\n", 0);
+}
+
+/*
+ * Safe version of setvar, returns 1 on success 0 on failure.
+ */
+
+int
+setvarsafe(const char *name, const char *val, int flags)
+{
+	struct jmploc jmploc;
+	struct jmploc *const savehandler = handler;
+	int err = 0;
+	int inton;
+
+	inton = is_int_on();
+	if (setjmp(jmploc.loc))
+		err = 1;
+	else {
+		handler = &jmploc;
+		setvar(name, val, flags);
+	}
+	handler = savehandler;
+	SETINTON(inton);
+	return err;
+}
+
+/*
+ * Set the value of a variable.  The flags argument is stored with the
+ * flags of the variable.  If val is NULL, the variable is unset.
+ */
+
+void
+setvar(const char *name, const char *val, int flags)
+{
+	const char *p;
+	size_t len;
+	size_t namelen;
+	size_t vallen;
+	char *nameeq;
+	int isbad;
+
+	isbad = 0;
+	p = name;
+	if (! is_name(*p))
+		isbad = 1;
+	p++;
+	for (;;) {
+		if (! is_in_name(*p)) {
+			if (*p == '\0' || *p == '=')
+				break;
+			isbad = 1;
+		}
+		p++;
+	}
+	namelen = p - name;
+	if (isbad)
+		error("%.*s: bad variable name", (int)namelen, name);
+	len = namelen + 2;		/* 2 is space for '=' and '\0' */
+	if (val == NULL) {
+		flags |= VUNSET;
+		vallen = 0;
+	} else {
+		vallen = strlen(val);
+		len += vallen;
+	}
+	INTOFF;
+	nameeq = ckmalloc(len);
+	memcpy(nameeq, name, namelen);
+	nameeq[namelen] = '=';
+	if (val)
+		memcpy(nameeq + namelen + 1, val, vallen + 1);
+	else
+		nameeq[namelen + 1] = '\0';
+	setvareq(nameeq, flags);
+	INTON;
+}
+
+static int
+localevar(const char *s)
+{
+	const char *const *ss;
+
+	if (*s != 'L')
+		return 0;
+	if (varequal(s + 1, "ANG"))
+		return 1;
+	if (strncmp(s + 1, "C_", 2) != 0)
+		return 0;
+	if (varequal(s + 3, "ALL"))
+		return 1;
+	for (ss = locale_names; *ss ; ss++)
+		if (varequal(s + 3, *ss + 3))
+			return 1;
+	return 0;
+}
+
+
+/*
+ * Sets/unsets an environment variable from a pointer that may actually be a
+ * pointer into environ where the string should not be manipulated.
+ */
+static void
+change_env(const char *s, int set)
+{
+	char *eqp;
+	char *ss;
+
+	INTOFF;
+	ss = savestr(s);
+	if ((eqp = strchr(ss, '=')) != NULL)
+		*eqp = '\0';
+	if (set && eqp != NULL)
+		(void) setenv(ss, eqp + 1, 1);
+	else
+		(void) unsetenv(ss);
+	ckfree(ss);
+	INTON;
+
+	return;
+}
+
+
+/*
+ * Same as setvar except that the variable and value are passed in
+ * the first argument as name=value.  Since the first argument will
+ * be actually stored in the table, it should not be a string that
+ * will go away.
+ */
+
+void
+setvareq(char *s, int flags)
+{
+	struct var *vp, **vpp;
+	int nlen;
+
+	if (aflag)
+		flags |= VEXPORT;
+	if (forcelocal && !(flags & (VNOSET | VNOLOCAL)))
+		mklocal(s);
+	vp = find_var(s, &vpp, &nlen);
+	if (vp != NULL) {
+		if (vp->flags & VREADONLY) {
+			if ((flags & (VTEXTFIXED|VSTACK)) == 0)
+				ckfree(s);
+			error("%.*s: is read only", vp->name_len, vp->text);
+		}
+		if (flags & VNOSET) {
+			if ((flags & (VTEXTFIXED|VSTACK)) == 0)
+				ckfree(s);
+			return;
+		}
+		INTOFF;
+
+		if (vp->func && (flags & VNOFUNC) == 0)
+			(*vp->func)(s + vp->name_len + 1);
+
+		if ((vp->flags & (VTEXTFIXED|VSTACK)) == 0)
+			ckfree(vp->text);
+
+		vp->flags &= ~(VTEXTFIXED|VSTACK|VUNSET);
+		vp->flags |= flags;
+		vp->text = s;
+
+		/*
+		 * We could roll this to a function, to handle it as
+		 * a regular variable function callback, but why bother?
+		 *
+		 * Note: this assumes iflag is not set to 1 initially.
+		 * As part of initvar(), this is called before arguments
+		 * are looked at.
+		 */
+		if ((vp == &vmpath || (vp == &vmail && ! mpathset())) &&
+		    iflag == 1)
+			chkmail(1);
+		if ((vp->flags & VEXPORT) && localevar(s)) {
+			change_env(s, 1);
+			(void) setlocale(LC_ALL, "");
+			updatecharset();
+		}
+		INTON;
+		return;
+	}
+	/* not found */
+	if (flags & VNOSET) {
+		if ((flags & (VTEXTFIXED|VSTACK)) == 0)
+			ckfree(s);
+		return;
+	}
+	INTOFF;
+	vp = ckmalloc(sizeof (*vp));
+	vp->flags = flags;
+	vp->text = s;
+	vp->name_len = nlen;
+	vp->next = *vpp;
+	vp->func = NULL;
+	*vpp = vp;
+	if ((vp->flags & VEXPORT) && localevar(s)) {
+		change_env(s, 1);
+		(void) setlocale(LC_ALL, "");
+		updatecharset();
+	}
+	INTON;
+}
+
+
+static void
+setvareq_const(const char *s, int flags)
+{
+	setvareq(__DECONST(char *, s), flags | VTEXTFIXED);
+}
+
+
+/*
+ * Process a linked list of variable assignments.
+ */
+
+void
+listsetvar(struct arglist *list, int flags)
+{
+	int i;
+
+	INTOFF;
+	for (i = 0; i < list->count; i++)
+		setvareq(savestr(list->args[i]), flags);
+	INTON;
+}
+
+
+
+/*
+ * Find the value of a variable.  Returns NULL if not set.
+ */
+
+char *
+lookupvar(const char *name)
+{
+	struct var *v;
+
+	v = find_var(name, NULL, NULL);
+	if (v == NULL || v->flags & VUNSET)
+		return NULL;
+	return v->text + v->name_len + 1;
+}
+
+
+
+/*
+ * Search the environment of a builtin command.  If the second argument
+ * is nonzero, return the value of a variable even if it hasn't been
+ * exported.
+ */
+
+char *
+bltinlookup(const char *name, int doall)
+{
+	struct var *v;
+	char *result;
+	int i;
+
+	result = NULL;
+	if (cmdenviron) for (i = 0; i < cmdenviron->count; i++) {
+		if (varequal(cmdenviron->args[i], name))
+			result = strchr(cmdenviron->args[i], '=') + 1;
+	}
+	if (result != NULL)
+		return result;
+
+	v = find_var(name, NULL, NULL);
+	if (v == NULL || v->flags & VUNSET ||
+	    (!doall && (v->flags & VEXPORT) == 0))
+		return NULL;
+	return v->text + v->name_len + 1;
+}
+
+
+/*
+ * Set up locale for a builtin (LANG/LC_* assignments).
+ */
+void
+bltinsetlocale(void)
+{
+	int act = 0;
+	char *loc, *locdef;
+	int i;
+
+	if (cmdenviron) for (i = 0; i < cmdenviron->count; i++) {
+		if (localevar(cmdenviron->args[i])) {
+			act = 1;
+			break;
+		}
+	}
+	if (!act)
+		return;
+	loc = bltinlookup("LC_ALL", 0);
+	INTOFF;
+	if (loc != NULL) {
+		setlocale(LC_ALL, loc);
+		INTON;
+		updatecharset();
+		return;
+	}
+	locdef = bltinlookup("LANG", 0);
+	for (i = 0; locale_names[i] != NULL; i++) {
+		loc = bltinlookup(locale_names[i], 0);
+		if (loc == NULL)
+			loc = locdef;
+		if (loc != NULL)
+			setlocale(locale_categories[i], loc);
+	}
+	INTON;
+	updatecharset();
+}
+
+/*
+ * Undo the effect of bltinlocaleset().
+ */
+void
+bltinunsetlocale(void)
+{
+	int i;
+
+	INTOFF;
+	if (cmdenviron) for (i = 0; i < cmdenviron->count; i++) {
+		if (localevar(cmdenviron->args[i])) {
+			setlocale(LC_ALL, "");
+			updatecharset();
+			break;
+		}
+	}
+	INTON;
+}
+
+/*
+ * Update the localeisutf8 flag.
+ */
+void
+updatecharset(void)
+{
+	char *charset;
+
+	charset = nl_langinfo(CODESET);
+	localeisutf8 = !strcmp(charset, "UTF-8");
+}
+
+void
+initcharset(void)
+{
+	updatecharset();
+	initial_localeisutf8 = localeisutf8;
+}
+
+/*
+ * Generate a list of exported variables.  This routine is used to construct
+ * the third argument to execve when executing a program.
+ */
+
+char **
+environment(void)
+{
+	int nenv;
+	struct var **vpp;
+	struct var *vp;
+	char **env, **ep;
+
+	nenv = 0;
+	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
+		for (vp = *vpp ; vp ; vp = vp->next)
+			if (vp->flags & VEXPORT)
+				nenv++;
+	}
+	ep = env = stalloc((nenv + 1) * sizeof *env);
+	for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
+		for (vp = *vpp ; vp ; vp = vp->next)
+			if (vp->flags & VEXPORT)
+				*ep++ = vp->text;
+	}
+	*ep = NULL;
+	return env;
+}
+
+
+static int
+var_compare(const void *a, const void *b)
+{
+	const char *const *sa, *const *sb;
+
+	sa = a;
+	sb = b;
+	/*
+	 * This compares two var=value strings which creates a different
+	 * order from what you would probably expect.  POSIX is somewhat
+	 * ambiguous on what should be sorted exactly.
+	 */
+	return strcoll(*sa, *sb);
+}
+
+
+/*
+ * Command to list all variables which are set.  This is invoked from the
+ * set command when it is called without any options or operands.
+ */
+
+int
+showvarscmd(int argc __unused, char **argv __unused)
+{
+	struct var **vpp;
+	struct var *vp;
+	const char *s;
+	const char **vars;
+	int i, n;
+
+	/*
+	 * POSIX requires us to sort the variables.
+	 */
+	n = 0;
+	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
+		for (vp = *vpp; vp; vp = vp->next) {
+			if (!(vp->flags & VUNSET))
+				n++;
+		}
+	}
+
+	INTOFF;
+	vars = ckmalloc(n * sizeof(*vars));
+	i = 0;
+	for (vpp = vartab; vpp < vartab + VTABSIZE; vpp++) {
+		for (vp = *vpp; vp; vp = vp->next) {
+			if (!(vp->flags & VUNSET))
+				vars[i++] = vp->text;
+		}
+	}
+
+	qsort(vars, n, sizeof(*vars), var_compare);
+	for (i = 0; i < n; i++) {
+		/*
+		 * Skip improper variable names so the output remains usable as
+		 * shell input.
+		 */
+		if (!isassignment(vars[i]))
+			continue;
+		s = strchr(vars[i], '=');
+		s++;
+		outbin(vars[i], s - vars[i], out1);
+		out1qstr(s);
+		out1c('\n');
+	}
+	ckfree(vars);
+	INTON;
+
+	return 0;
+}
+
+
+
+/*
+ * The export and readonly commands.
+ */
+
+int
+exportcmd(int argc __unused, char **argv)
+{
+	struct var **vpp;
+	struct var *vp;
+	char **ap;
+	char *name;
+	char *p;
+	char *cmdname;
+	int ch, values;
+	int flag = argv[0][0] == 'r'? VREADONLY : VEXPORT;
+
+	cmdname = argv[0];
+	values = 0;
+	while ((ch = nextopt("p")) != '\0') {
+		switch (ch) {
+		case 'p':
+			values = 1;
+			break;
+		}
+	}
+
+	if (values && *argptr != NULL)
+		error("-p requires no arguments");
+	if (*argptr != NULL) {
+		for (ap = argptr; (name = *ap) != NULL; ap++) {
+			if ((p = strchr(name, '=')) != NULL) {
+				p++;
+			} else {
+				vp = find_var(name, NULL, NULL);
+				if (vp != NULL) {
+					vp->flags |= flag;
+					if ((vp->flags & VEXPORT) && localevar(vp->text)) {
+						change_env(vp->text, 1);
+						(void) setlocale(LC_ALL, "");
+						updatecharset();
+					}
+					continue;
+				}
+			}
+			setvar(name, p, flag);
+		}
+	} else {
+		for (vpp = vartab ; vpp < vartab + VTABSIZE ; vpp++) {
+			for (vp = *vpp ; vp ; vp = vp->next) {
+				if (vp->flags & flag) {
+					if (values) {
+						/*
+						 * Skip improper variable names
+						 * so the output remains usable
+						 * as shell input.
+						 */
+						if (!isassignment(vp->text))
+							continue;
+						out1str(cmdname);
+						out1c(' ');
+					}
+					if (values && !(vp->flags & VUNSET)) {
+						outbin(vp->text,
+						    vp->name_len + 1, out1);
+						out1qstr(vp->text +
+						    vp->name_len + 1);
+					} else
+						outbin(vp->text, vp->name_len,
+						    out1);
+					out1c('\n');
+				}
+			}
+		}
+	}
+	return 0;
+}
+
+
+/*
+ * The "local" command.
+ */
+
+int
+localcmd(int argc __unused, char **argv __unused)
+{
+	char *name;
+
+	nextopt("");
+	if (! in_function())
+		error("Not in a function");
+	while ((name = *argptr++) != NULL) {
+		mklocal(name);
+	}
+	return 0;
+}
+
+
+/*
+ * Make a variable a local variable.  When a variable is made local, it's
+ * value and flags are saved in a localvar structure.  The saved values
+ * will be restored when the shell function returns.  We handle the name
+ * "-" as a special case.
+ */
+
+void
+mklocal(char *name)
+{
+	struct localvar *lvp;
+	struct var **vpp;
+	struct var *vp;
+
+	INTOFF;
+	lvp = ckmalloc(sizeof (struct localvar));
+	if (name[0] == '-' && name[1] == '\0') {
+		lvp->text = ckmalloc(sizeof optval);
+		memcpy(lvp->text, optval, sizeof optval);
+		vp = NULL;
+	} else {
+		vp = find_var(name, &vpp, NULL);
+		if (vp == NULL) {
+			if (strchr(name, '='))
+				setvareq(savestr(name), VSTRFIXED | VNOLOCAL);
+			else
+				setvar(name, NULL, VSTRFIXED | VNOLOCAL);
+			vp = *vpp;	/* the new variable */
+			lvp->text = NULL;
+			lvp->flags = VUNSET;
+		} else {
+			lvp->text = vp->text;
+			lvp->flags = vp->flags;
+			vp->flags |= VSTRFIXED|VTEXTFIXED;
+			if (name[vp->name_len] == '=')
+				setvareq(savestr(name), VNOLOCAL);
+		}
+	}
+	lvp->vp = vp;
+	lvp->next = localvars;
+	localvars = lvp;
+	INTON;
+}
+
+
+/*
+ * Called after a function returns.
+ */
+
+void
+poplocalvars(void)
+{
+	struct localvar *lvp;
+	struct var *vp;
+	int islocalevar;
+
+	INTOFF;
+	while ((lvp = localvars) != NULL) {
+		localvars = lvp->next;
+		vp = lvp->vp;
+		if (vp == NULL) {	/* $- saved */
+			memcpy(optval, lvp->text, sizeof optval);
+			ckfree(lvp->text);
+			optschanged();
+		} else if ((lvp->flags & (VUNSET|VSTRFIXED)) == VUNSET) {
+			vp->flags &= ~VREADONLY;
+			(void)unsetvar(vp->text);
+		} else {
+			islocalevar = (vp->flags | lvp->flags) & VEXPORT &&
+			    localevar(lvp->text);
+			if ((vp->flags & VTEXTFIXED) == 0)
+				ckfree(vp->text);
+			vp->flags = lvp->flags;
+			vp->text = lvp->text;
+			if (vp->func)
+				(*vp->func)(vp->text + vp->name_len + 1);
+			if (islocalevar) {
+				change_env(vp->text, vp->flags & VEXPORT &&
+				    (vp->flags & VUNSET) == 0);
+				setlocale(LC_ALL, "");
+				updatecharset();
+			}
+		}
+		ckfree(lvp);
+	}
+	INTON;
+}
+
+
+int
+setvarcmd(int argc, char **argv)
+{
+	if (argc <= 2)
+		return unsetcmd(argc, argv);
+	else if (argc == 3)
+		setvar(argv[1], argv[2], 0);
+	else
+		error("too many arguments");
+	return 0;
+}
+
+
+/*
+ * The unset builtin command.
+ */
+
+int
+unsetcmd(int argc __unused, char **argv __unused)
+{
+	char **ap;
+	int i;
+	int flg_func = 0;
+	int flg_var = 0;
+	int ret = 0;
+
+	while ((i = nextopt("vf")) != '\0') {
+		if (i == 'f')
+			flg_func = 1;
+		else
+			flg_var = 1;
+	}
+	if (flg_func == 0 && flg_var == 0)
+		flg_var = 1;
+
+	INTOFF;
+	for (ap = argptr; *ap ; ap++) {
+		if (flg_func)
+			ret |= unsetfunc(*ap);
+		if (flg_var)
+			ret |= unsetvar(*ap);
+	}
+	INTON;
+	return ret;
+}
+
+
+/*
+ * Unset the specified variable.
+ * Called with interrupts off.
+ */
+
+int
+unsetvar(const char *s)
+{
+	struct var **vpp;
+	struct var *vp;
+
+	vp = find_var(s, &vpp, NULL);
+	if (vp == NULL)
+		return (0);
+	if (vp->flags & VREADONLY)
+		return (1);
+	if (vp->text[vp->name_len + 1] != '\0')
+		setvar(s, "", 0);
+	if ((vp->flags & VEXPORT) && localevar(vp->text)) {
+		change_env(s, 0);
+		setlocale(LC_ALL, "");
+		updatecharset();
+	}
+	vp->flags &= ~VEXPORT;
+	vp->flags |= VUNSET;
+	if ((vp->flags & VSTRFIXED) == 0) {
+		if ((vp->flags & VTEXTFIXED) == 0)
+			ckfree(vp->text);
+		*vpp = vp->next;
+		ckfree(vp);
+	}
+	return (0);
+}
+
+
+
+/*
+ * Returns true if the two strings specify the same variable.  The first
+ * variable name is terminated by '='; the second may be terminated by
+ * either '=' or '\0'.
+ */
+
+static int
+varequal(const char *p, const char *q)
+{
+	while (*p == *q++) {
+		if (*p++ == '=')
+			return 1;
+	}
+	if (*p == '=' && *(q - 1) == '\0')
+		return 1;
+	return 0;
+}
+
+/*
+ * Search for a variable.
+ * 'name' may be terminated by '=' or a NUL.
+ * vppp is set to the pointer to vp, or the list head if vp isn't found
+ * lenp is set to the number of characters in 'name'
+ */
+
+static struct var *
+find_var(const char *name, struct var ***vppp, int *lenp)
+{
+	unsigned int hashval;
+	int len;
+	struct var *vp, **vpp;
+	const char *p = name;
+
+	hashval = 0;
+	while (*p && *p != '=')
+		hashval = 2 * hashval + (unsigned char)*p++;
+	len = p - name;
+
+	if (lenp)
+		*lenp = len;
+	vpp = &vartab[hashval % VTABSIZE];
+	if (vppp)
+		*vppp = vpp;
+
+	for (vp = *vpp ; vp ; vpp = &vp->next, vp = *vpp) {
+		if (vp->name_len != len)
+			continue;
+		if (memcmp(vp->text, name, len) != 0)
+			continue;
+		if (vppp)
+			*vppp = vpp;
+		return vp;
+	}
+	return NULL;
+}