Kconfig!

Works on Kontron, qemu, and serengeti. 

Signed-off-by: Patrick Georgi <patrick.georgi@coresystems.de>

tested on abuild only. 

Acked-by: Ronald G. Minnich <rminnich@gmail.com>




git-svn-id: svn://svn.coreboot.org/coreboot/trunk@4534 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1

1 files changed, 917 insertions, 0 deletions

diff --git a/util/kconfig/symbol.c b/util/kconfig/symbol.c
new file mode 100644
index 0000000000..4a03191ad1
--- /dev/null
+++ b/util/kconfig/symbol.c
@@ -0,0 +1,917 @@
+/*
+ * Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
+ * Released under the terms of the GNU GPL v2.0.
+ */
+
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+#include <regex.h>
+#include <sys/utsname.h>
+
+#define LKC_DIRECT_LINK
+#include "lkc.h"
+
+struct symbol symbol_yes = {
+	.name = "y",
+	.curr = { "y", yes },
+	.flags = SYMBOL_CONST|SYMBOL_VALID,
+}, symbol_mod = {
+	.name = "m",
+	.curr = { "m", mod },
+	.flags = SYMBOL_CONST|SYMBOL_VALID,
+}, symbol_no = {
+	.name = "n",
+	.curr = { "n", no },
+	.flags = SYMBOL_CONST|SYMBOL_VALID,
+}, symbol_empty = {
+	.name = "",
+	.curr = { "", no },
+	.flags = SYMBOL_VALID,
+};
+
+struct symbol *sym_defconfig_list;
+struct symbol *modules_sym;
+tristate modules_val;
+
+struct expr *sym_env_list;
+
+void sym_add_default(struct symbol *sym, const char *def)
+{
+	struct property *prop = prop_alloc(P_DEFAULT, sym);
+
+	prop->expr = expr_alloc_symbol(sym_lookup(def, 1));
+}
+
+void sym_init(void)
+{
+	struct symbol *sym;
+	struct utsname uts;
+	static bool inited = false;
+
+	if (inited)
+		return;
+	inited = true;
+
+	uname(&uts);
+
+	sym = sym_lookup("UNAME_RELEASE", 0);
+	sym->type = S_STRING;
+	sym->flags |= SYMBOL_AUTO;
+	sym_add_default(sym, uts.release);
+}
+
+enum symbol_type sym_get_type(struct symbol *sym)
+{
+	enum symbol_type type = sym->type;
+
+	if (type == S_TRISTATE) {
+		if (sym_is_choice_value(sym) && sym->visible == yes)
+			type = S_BOOLEAN;
+		else if (modules_val == no)
+			type = S_BOOLEAN;
+	}
+	return type;
+}
+
+const char *sym_type_name(enum symbol_type type)
+{
+	switch (type) {
+	case S_BOOLEAN:
+		return "boolean";
+	case S_TRISTATE:
+		return "tristate";
+	case S_INT:
+		return "integer";
+	case S_HEX:
+		return "hex";
+	case S_STRING:
+		return "string";
+	case S_UNKNOWN:
+		return "unknown";
+	case S_OTHER:
+		break;
+	}
+	return "???";
+}
+
+struct property *sym_get_choice_prop(struct symbol *sym)
+{
+	struct property *prop;
+
+	for_all_choices(sym, prop)
+		return prop;
+	return NULL;
+}
+
+struct property *sym_get_env_prop(struct symbol *sym)
+{
+	struct property *prop;
+
+	for_all_properties(sym, prop, P_ENV)
+		return prop;
+	return NULL;
+}
+
+struct property *sym_get_default_prop(struct symbol *sym)
+{
+	struct property *prop;
+
+	for_all_defaults(sym, prop) {
+		prop->visible.tri = expr_calc_value(prop->visible.expr);
+		if (prop->visible.tri != no)
+			return prop;
+	}
+	return NULL;
+}
+
+struct property *sym_get_range_prop(struct symbol *sym)
+{
+	struct property *prop;
+
+	for_all_properties(sym, prop, P_RANGE) {
+		prop->visible.tri = expr_calc_value(prop->visible.expr);
+		if (prop->visible.tri != no)
+			return prop;
+	}
+	return NULL;
+}
+
+static int sym_get_range_val(struct symbol *sym, int base)
+{
+	sym_calc_value(sym);
+	switch (sym->type) {
+	case S_INT:
+		base = 10;
+		break;
+	case S_HEX:
+		base = 16;
+		break;
+	default:
+		break;
+	}
+	return strtol(sym->curr.val, NULL, base);
+}
+
+static void sym_validate_range(struct symbol *sym)
+{
+	struct property *prop;
+	int base, val, val2;
+	char str[64];
+
+	switch (sym->type) {
+	case S_INT:
+		base = 10;
+		break;
+	case S_HEX:
+		base = 16;
+		break;
+	default:
+		return;
+	}
+	prop = sym_get_range_prop(sym);
+	if (!prop)
+		return;
+	val = strtol(sym->curr.val, NULL, base);
+	val2 = sym_get_range_val(prop->expr->left.sym, base);
+	if (val >= val2) {
+		val2 = sym_get_range_val(prop->expr->right.sym, base);
+		if (val <= val2)
+			return;
+	}
+	if (sym->type == S_INT)
+		sprintf(str, "%d", val2);
+	else
+		sprintf(str, "0x%x", val2);
+	sym->curr.val = strdup(str);
+}
+
+static void sym_calc_visibility(struct symbol *sym)
+{
+	struct property *prop;
+	tristate tri;
+
+	/* any prompt visible? */
+	tri = no;
+	for_all_prompts(sym, prop) {
+		prop->visible.tri = expr_calc_value(prop->visible.expr);
+		tri = EXPR_OR(tri, prop->visible.tri);
+	}
+	if (tri == mod && (sym->type != S_TRISTATE || modules_val == no))
+		tri = yes;
+	if (sym->visible != tri) {
+		sym->visible = tri;
+		sym_set_changed(sym);
+	}
+	if (sym_is_choice_value(sym))
+		return;
+	tri = no;
+	if (sym->rev_dep.expr)
+		tri = expr_calc_value(sym->rev_dep.expr);
+	if (tri == mod && sym_get_type(sym) == S_BOOLEAN)
+		tri = yes;
+	if (sym->rev_dep.tri != tri) {
+		sym->rev_dep.tri = tri;
+		sym_set_changed(sym);
+	}
+}
+
+static struct symbol *sym_calc_choice(struct symbol *sym)
+{
+	struct symbol *def_sym;
+	struct property *prop;
+	struct expr *e;
+
+	/* is the user choice visible? */
+	def_sym = sym->def[S_DEF_USER].val;
+	if (def_sym) {
+		sym_calc_visibility(def_sym);
+		if (def_sym->visible != no)
+			return def_sym;
+	}
+
+	/* any of the defaults visible? */
+	for_all_defaults(sym, prop) {
+		prop->visible.tri = expr_calc_value(prop->visible.expr);
+		if (prop->visible.tri == no)
+			continue;
+		def_sym = prop_get_symbol(prop);
+		sym_calc_visibility(def_sym);
+		if (def_sym->visible != no)
+			return def_sym;
+	}
+
+	/* just get the first visible value */
+	prop = sym_get_choice_prop(sym);
+	expr_list_for_each_sym(prop->expr, e, def_sym) {
+		sym_calc_visibility(def_sym);
+		if (def_sym->visible != no)
+			return def_sym;
+	}
+
+	/* no choice? reset tristate value */
+	sym->curr.tri = no;
+	return NULL;
+}
+
+void sym_calc_value(struct symbol *sym)
+{
+	struct symbol_value newval, oldval;
+	struct property *prop;
+	struct expr *e;
+
+	if (!sym)
+		return;
+
+	if (sym->flags & SYMBOL_VALID)
+		return;
+	sym->flags |= SYMBOL_VALID;
+
+	oldval = sym->curr;
+
+	switch (sym->type) {
+	case S_INT:
+	case S_HEX:
+	case S_STRING:
+		newval = symbol_empty.curr;
+		break;
+	case S_BOOLEAN:
+	case S_TRISTATE:
+		newval = symbol_no.curr;
+		break;
+	default:
+		sym->curr.val = sym->name;
+		sym->curr.tri = no;
+		return;
+	}
+	if (!sym_is_choice_value(sym))
+		sym->flags &= ~SYMBOL_WRITE;
+
+	sym_calc_visibility(sym);
+
+	/* set default if recursively called */
+	sym->curr = newval;
+
+	switch (sym_get_type(sym)) {
+	case S_BOOLEAN:
+	case S_TRISTATE:
+		if (sym_is_choice_value(sym) && sym->visible == yes) {
+			prop = sym_get_choice_prop(sym);
+			newval.tri = (prop_get_symbol(prop)->curr.val == sym) ? yes : no;
+		} else {
+			if (sym->visible != no) {
+				/* if the symbol is visible use the user value
+				 * if available, otherwise try the default value
+				 */
+				sym->flags |= SYMBOL_WRITE;
+				if (sym_has_value(sym)) {
+					newval.tri = EXPR_AND(sym->def[S_DEF_USER].tri,
+							      sym->visible);
+					goto calc_newval;
+				}
+			}
+			if (sym->rev_dep.tri != no)
+				sym->flags |= SYMBOL_WRITE;
+			if (!sym_is_choice(sym)) {
+				prop = sym_get_default_prop(sym);
+				if (prop) {
+					sym->flags |= SYMBOL_WRITE;
+					newval.tri = EXPR_AND(expr_calc_value(prop->expr),
+							      prop->visible.tri);
+				}
+			}
+		calc_newval:
+			newval.tri = EXPR_OR(newval.tri, sym->rev_dep.tri);
+		}
+		if (newval.tri == mod && sym_get_type(sym) == S_BOOLEAN)
+			newval.tri = yes;
+		break;
+	case S_STRING:
+	case S_HEX:
+	case S_INT:
+		if (sym->visible != no) {
+			sym->flags |= SYMBOL_WRITE;
+			if (sym_has_value(sym)) {
+				newval.val = sym->def[S_DEF_USER].val;
+				break;
+			}
+		}
+		prop = sym_get_default_prop(sym);
+		if (prop) {
+			struct symbol *ds = prop_get_symbol(prop);
+			if (ds) {
+				sym->flags |= SYMBOL_WRITE;
+				sym_calc_value(ds);
+				newval.val = ds->curr.val;
+			}
+		}
+		break;
+	default:
+		;
+	}
+
+	if (sym->flags & SYMBOL_AUTO)
+		sym->flags &= ~SYMBOL_WRITE;
+
+	sym->curr = newval;
+	if (sym_is_choice(sym) && newval.tri == yes)
+		sym->curr.val = sym_calc_choice(sym);
+	sym_validate_range(sym);
+
+	if (memcmp(&oldval, &sym->curr, sizeof(oldval))) {
+		sym_set_changed(sym);
+		if (modules_sym == sym) {
+			sym_set_all_changed();
+			modules_val = modules_sym->curr.tri;
+		}
+	}
+
+	if (sym_is_choice(sym)) {
+		struct symbol *choice_sym;
+		int flags = sym->flags & (SYMBOL_CHANGED | SYMBOL_WRITE);
+
+		prop = sym_get_choice_prop(sym);
+		expr_list_for_each_sym(prop->expr, e, choice_sym) {
+			choice_sym->flags |= flags;
+			if (flags & SYMBOL_CHANGED)
+				sym_set_changed(choice_sym);
+		}
+	}
+}
+
+void sym_clear_all_valid(void)
+{
+	struct symbol *sym;
+	int i;
+
+	for_all_symbols(i, sym)
+		sym->flags &= ~SYMBOL_VALID;
+	sym_add_change_count(1);
+	if (modules_sym)
+		sym_calc_value(modules_sym);
+}
+
+void sym_set_changed(struct symbol *sym)
+{
+	struct property *prop;
+
+	sym->flags |= SYMBOL_CHANGED;
+	for (prop = sym->prop; prop; prop = prop->next) {
+		if (prop->menu)
+			prop->menu->flags |= MENU_CHANGED;
+	}
+}
+
+void sym_set_all_changed(void)
+{
+	struct symbol *sym;
+	int i;
+
+	for_all_symbols(i, sym)
+		sym_set_changed(sym);
+}
+
+bool sym_tristate_within_range(struct symbol *sym, tristate val)
+{
+	int type = sym_get_type(sym);
+
+	if (sym->visible == no)
+		return false;
+
+	if (type != S_BOOLEAN && type != S_TRISTATE)
+		return false;
+
+	if (type == S_BOOLEAN && val == mod)
+		return false;
+	if (sym->visible <= sym->rev_dep.tri)
+		return false;
+	if (sym_is_choice_value(sym) && sym->visible == yes)
+		return val == yes;
+	return val >= sym->rev_dep.tri && val <= sym->visible;
+}
+
+bool sym_set_tristate_value(struct symbol *sym, tristate val)
+{
+	tristate oldval = sym_get_tristate_value(sym);
+
+	if (oldval != val && !sym_tristate_within_range(sym, val))
+		return false;
+
+	if (!(sym->flags & SYMBOL_DEF_USER)) {
+		sym->flags |= SYMBOL_DEF_USER;
+		sym_set_changed(sym);
+	}
+	/*
+	 * setting a choice value also resets the new flag of the choice
+	 * symbol and all other choice values.
+	 */
+	if (sym_is_choice_value(sym) && val == yes) {
+		struct symbol *cs = prop_get_symbol(sym_get_choice_prop(sym));
+		struct property *prop;
+		struct expr *e;
+
+		cs->def[S_DEF_USER].val = sym;
+		cs->flags |= SYMBOL_DEF_USER;
+		prop = sym_get_choice_prop(cs);
+		for (e = prop->expr; e; e = e->left.expr) {
+			if (e->right.sym->visible != no)
+				e->right.sym->flags |= SYMBOL_DEF_USER;
+		}
+	}
+
+	sym->def[S_DEF_USER].tri = val;
+	if (oldval != val)
+		sym_clear_all_valid();
+
+	return true;
+}
+
+tristate sym_toggle_tristate_value(struct symbol *sym)
+{
+	tristate oldval, newval;
+
+	oldval = newval = sym_get_tristate_value(sym);
+	do {
+		switch (newval) {
+		case no:
+			newval = mod;
+			break;
+		case mod:
+			newval = yes;
+			break;
+		case yes:
+			newval = no;
+			break;
+		}
+		if (sym_set_tristate_value(sym, newval))
+			break;
+	} while (oldval != newval);
+	return newval;
+}
+
+bool sym_string_valid(struct symbol *sym, const char *str)
+{
+	signed char ch;
+
+	switch (sym->type) {
+	case S_STRING:
+		return true;
+	case S_INT:
+		ch = *str++;
+		if (ch == '-')
+			ch = *str++;
+		if (!isdigit(ch))
+			return false;
+		if (ch == '0' && *str != 0)
+			return false;
+		while ((ch = *str++)) {
+			if (!isdigit(ch))
+				return false;
+		}
+		return true;
+	case S_HEX:
+		if (str[0] == '0' && (str[1] == 'x' || str[1] == 'X'))
+			str += 2;
+		ch = *str++;
+		do {
+			if (!isxdigit(ch))
+				return false;
+		} while ((ch = *str++));
+		return true;
+	case S_BOOLEAN:
+	case S_TRISTATE:
+		switch (str[0]) {
+		case 'y': case 'Y':
+		case 'm': case 'M':
+		case 'n': case 'N':
+			return true;
+		}
+		return false;
+	default:
+		return false;
+	}
+}
+
+bool sym_string_within_range(struct symbol *sym, const char *str)
+{
+	struct property *prop;
+	int val;
+
+	switch (sym->type) {
+	case S_STRING:
+		return sym_string_valid(sym, str);
+	case S_INT:
+		if (!sym_string_valid(sym, str))
+			return false;
+		prop = sym_get_range_prop(sym);
+		if (!prop)
+			return true;
+		val = strtol(str, NULL, 10);
+		return val >= sym_get_range_val(prop->expr->left.sym, 10) &&
+		       val <= sym_get_range_val(prop->expr->right.sym, 10);
+	case S_HEX:
+		if (!sym_string_valid(sym, str))
+			return false;
+		prop = sym_get_range_prop(sym);
+		if (!prop)
+			return true;
+		val = strtol(str, NULL, 16);
+		return val >= sym_get_range_val(prop->expr->left.sym, 16) &&
+		       val <= sym_get_range_val(prop->expr->right.sym, 16);
+	case S_BOOLEAN:
+	case S_TRISTATE:
+		switch (str[0]) {
+		case 'y': case 'Y':
+			return sym_tristate_within_range(sym, yes);
+		case 'm': case 'M':
+			return sym_tristate_within_range(sym, mod);
+		case 'n': case 'N':
+			return sym_tristate_within_range(sym, no);
+		}
+		return false;
+	default:
+		return false;
+	}
+}
+
+bool sym_set_string_value(struct symbol *sym, const char *newval)
+{
+	const char *oldval;
+	char *val;
+	int size;
+
+	switch (sym->type) {
+	case S_BOOLEAN:
+	case S_TRISTATE:
+		switch (newval[0]) {
+		case 'y': case 'Y':
+			return sym_set_tristate_value(sym, yes);
+		case 'm': case 'M':
+			return sym_set_tristate_value(sym, mod);
+		case 'n': case 'N':
+			return sym_set_tristate_value(sym, no);
+		}
+		return false;
+	default:
+		;
+	}
+
+	if (!sym_string_within_range(sym, newval))
+		return false;
+
+	if (!(sym->flags & SYMBOL_DEF_USER)) {
+		sym->flags |= SYMBOL_DEF_USER;
+		sym_set_changed(sym);
+	}
+
+	oldval = sym->def[S_DEF_USER].val;
+	size = strlen(newval) + 1;
+	if (sym->type == S_HEX && (newval[0] != '0' || (newval[1] != 'x' && newval[1] != 'X'))) {
+		size += 2;
+		sym->def[S_DEF_USER].val = val = malloc(size);
+		*val++ = '0';
+		*val++ = 'x';
+	} else if (!oldval || strcmp(oldval, newval))
+		sym->def[S_DEF_USER].val = val = malloc(size);
+	else
+		return true;
+
+	strcpy(val, newval);
+	free((void *)oldval);
+	sym_clear_all_valid();
+
+	return true;
+}
+
+const char *sym_get_string_value(struct symbol *sym)
+{
+	tristate val;
+
+	switch (sym->type) {
+	case S_BOOLEAN:
+	case S_TRISTATE:
+		val = sym_get_tristate_value(sym);
+		switch (val) {
+		case no:
+			return "n";
+		case mod:
+			return "m";
+		case yes:
+			return "y";
+		}
+		break;
+	default:
+		;
+	}
+	return (const char *)sym->curr.val;
+}
+
+bool sym_is_changable(struct symbol *sym)
+{
+	return sym->visible > sym->rev_dep.tri;
+}
+
+struct symbol *sym_lookup(const char *name, int isconst)
+{
+	struct symbol *symbol;
+	const char *ptr;
+	char *new_name;
+	int hash = 0;
+
+	if (name) {
+		if (name[0] && !name[1]) {
+			switch (name[0]) {
+			case 'y': return &symbol_yes;
+			case 'm': return &symbol_mod;
+			case 'n': return &symbol_no;
+			}
+		}
+		for (ptr = name; *ptr; ptr++)
+			hash += *ptr;
+		hash &= 0xff;
+
+		for (symbol = symbol_hash[hash]; symbol; symbol = symbol->next) {
+			if (!strcmp(symbol->name, name)) {
+				if ((isconst && symbol->flags & SYMBOL_CONST) ||
+				    (!isconst && !(symbol->flags & SYMBOL_CONST)))
+					return symbol;
+			}
+		}
+		new_name = strdup(name);
+	} else {
+		new_name = NULL;
+		hash = 256;
+	}
+
+	symbol = malloc(sizeof(*symbol));
+	memset(symbol, 0, sizeof(*symbol));
+	symbol->name = new_name;
+	symbol->type = S_UNKNOWN;
+	if (isconst)
+		symbol->flags |= SYMBOL_CONST;
+
+	symbol->next = symbol_hash[hash];
+	symbol_hash[hash] = symbol;
+
+	return symbol;
+}
+
+struct symbol *sym_find(const char *name)
+{
+	struct symbol *symbol = NULL;
+	const char *ptr;
+	int hash = 0;
+
+	if (!name)
+		return NULL;
+
+	if (name[0] && !name[1]) {
+		switch (name[0]) {
+		case 'y': return &symbol_yes;
+		case 'm': return &symbol_mod;
+		case 'n': return &symbol_no;
+		}
+	}
+	for (ptr = name; *ptr; ptr++)
+		hash += *ptr;
+	hash &= 0xff;
+
+	for (symbol = symbol_hash[hash]; symbol; symbol = symbol->next) {
+		if (!strcmp(symbol->name, name) &&
+		    !(symbol->flags & SYMBOL_CONST))
+				break;
+	}
+
+	return symbol;
+}
+
+struct symbol **sym_re_search(const char *pattern)
+{
+	struct symbol *sym, **sym_arr = NULL;
+	int i, cnt, size;
+	regex_t re;
+
+	cnt = size = 0;
+	/* Skip if empty */
+	if (strlen(pattern) == 0)
+		return NULL;
+	if (regcomp(&re, pattern, REG_EXTENDED|REG_NOSUB|REG_ICASE))
+		return NULL;
+
+	for_all_symbols(i, sym) {
+		if (sym->flags & SYMBOL_CONST || !sym->name)
+			continue;
+		if (regexec(&re, sym->name, 0, NULL, 0))
+			continue;
+		if (cnt + 1 >= size) {
+			void *tmp = sym_arr;
+			size += 16;
+			sym_arr = realloc(sym_arr, size * sizeof(struct symbol *));
+			if (!sym_arr) {
+				free(tmp);
+				return NULL;
+			}
+		}
+		sym_arr[cnt++] = sym;
+	}
+	if (sym_arr)
+		sym_arr[cnt] = NULL;
+	regfree(&re);
+
+	return sym_arr;
+}
+
+
+struct symbol *sym_check_deps(struct symbol *sym);
+
+static struct symbol *sym_check_expr_deps(struct expr *e)
+{
+	struct symbol *sym;
+
+	if (!e)
+		return NULL;
+	switch (e->type) {
+	case E_OR:
+	case E_AND:
+		sym = sym_check_expr_deps(e->left.expr);
+		if (sym)
+			return sym;
+		return sym_check_expr_deps(e->right.expr);
+	case E_NOT:
+		return sym_check_expr_deps(e->left.expr);
+	case E_EQUAL:
+	case E_UNEQUAL:
+		sym = sym_check_deps(e->left.sym);
+		if (sym)
+			return sym;
+		return sym_check_deps(e->right.sym);
+	case E_SYMBOL:
+		return sym_check_deps(e->left.sym);
+	default:
+		break;
+	}
+	printf("Oops! How to check %d?\n", e->type);
+	return NULL;
+}
+
+/* return NULL when dependencies are OK */
+struct symbol *sym_check_deps(struct symbol *sym)
+{
+	struct symbol *sym2;
+	struct property *prop;
+
+	if (sym->flags & SYMBOL_CHECK) {
+		fprintf(stderr, "%s:%d:error: found recursive dependency: %s",
+		        sym->prop->file->name, sym->prop->lineno, sym->name);
+		return sym;
+	}
+	if (sym->flags & SYMBOL_CHECKED)
+		return NULL;
+
+	sym->flags |= (SYMBOL_CHECK | SYMBOL_CHECKED);
+	sym2 = sym_check_expr_deps(sym->rev_dep.expr);
+	if (sym2)
+		goto out;
+
+	for (prop = sym->prop; prop; prop = prop->next) {
+		if (prop->type == P_CHOICE || prop->type == P_SELECT)
+			continue;
+		sym2 = sym_check_expr_deps(prop->visible.expr);
+		if (sym2)
+			goto out;
+		if (prop->type != P_DEFAULT || sym_is_choice(sym))
+			continue;
+		sym2 = sym_check_expr_deps(prop->expr);
+		if (sym2)
+			goto out;
+	}
+out:
+	if (sym2)
+		fprintf(stderr, " -> %s%s", sym->name, sym2 == sym? "\n": "");
+	sym->flags &= ~SYMBOL_CHECK;
+	return sym2;
+}
+
+struct property *prop_alloc(enum prop_type type, struct symbol *sym)
+{
+	struct property *prop;
+	struct property **propp;
+
+	prop = malloc(sizeof(*prop));
+	memset(prop, 0, sizeof(*prop));
+	prop->type = type;
+	prop->sym = sym;
+	prop->file = current_file;
+	prop->lineno = zconf_lineno();
+
+	/* append property to the prop list of symbol */
+	if (sym) {
+		for (propp = &sym->prop; *propp; propp = &(*propp)->next)
+			;
+		*propp = prop;
+	}
+
+	return prop;
+}
+
+struct symbol *prop_get_symbol(struct property *prop)
+{
+	if (prop->expr && (prop->expr->type == E_SYMBOL ||
+			   prop->expr->type == E_LIST))
+		return prop->expr->left.sym;
+	return NULL;
+}
+
+const char *prop_get_type_name(enum prop_type type)
+{
+	switch (type) {
+	case P_PROMPT:
+		return "prompt";
+	case P_ENV:
+		return "env";
+	case P_COMMENT:
+		return "comment";
+	case P_MENU:
+		return "menu";
+	case P_DEFAULT:
+		return "default";
+	case P_CHOICE:
+		return "choice";
+	case P_SELECT:
+		return "select";
+	case P_RANGE:
+		return "range";
+	case P_UNKNOWN:
+		break;
+	}
+	return "unknown";
+}
+
+void prop_add_env(const char *env)
+{
+	struct symbol *sym, *sym2;
+	struct property *prop;
+	char *p;
+
+	sym = current_entry->sym;
+	sym->flags |= SYMBOL_AUTO;
+	for_all_properties(sym, prop, P_ENV) {
+		sym2 = prop_get_symbol(prop);
+		if (strcmp(sym2->name, env))
+			menu_warn(current_entry, "redefining environment symbol from %s",
+				  sym2->name);
+		return;
+	}
+
+	prop = prop_alloc(P_ENV, sym);
+	prop->expr = expr_alloc_symbol(sym_lookup(env, 1));
+
+	sym_env_list = expr_alloc_one(E_LIST, sym_env_list);
+	sym_env_list->right.sym = sym;
+
+	p = getenv(env);
+	if (p)
+		sym_add_default(sym, p);
+	else
+		menu_warn(current_entry, "environment variable %s undefined", env);
+}