+#define to_stmt_simple(stmt) \
+ container_of(stmt, struct grub2_statement_simple, st)
+#define to_stmt_if(stmt) \
+ container_of(stmt, struct grub2_statement_if, st)
+#define to_stmt_menuentry(stmt) \
+ container_of(stmt, struct grub2_statement_menuentry, st)
+
+struct env_entry {
+ const char *name;
+ const char *value;
+ struct list_item list;
+};
+
+const char *script_env_get(struct grub2_script *script, const char *name)
+{
+ struct env_entry *entry;
+
+ list_for_each_entry(&script->environment, entry, list)
+ if (!strcmp(entry->name, name))
+ return entry->value;
+
+ return NULL;
+}
+
+void script_env_set(struct grub2_script *script,
+ const char *name, const char *value)
+{
+ struct env_entry *e, *entry = NULL;
+
+ list_for_each_entry(&script->environment, e, list) {
+ if (!strcmp(e->name, name)) {
+ entry = e;
+ break;
+ }
+ }
+
+ if (!entry) {
+ entry = talloc(script, struct env_entry);
+ entry->name = name;
+ list_add(&script->environment, &entry->list);
+ }
+
+ entry->value = value;
+}
+
+static bool expand_var(struct grub2_script *script, struct grub2_word *word)
+{
+ const char *val;
+
+ val = script_env_get(script, word->name);
+ if (!val)
+ val = "";
+
+ word->text = talloc_strdup(script, val);
+
+ return true;
+}
+
+static bool is_delim(char c)
+{
+ return c == ' ' || c == '\t';
+}
+
+/* For non-double-quoted variable expansions, we may need to split the
+ * variable's value into multiple argv items.
+ *
+ * This function sets the word->text to the initial set of non-delimiter chars
+ * in the expanded var value. We then skip any delimiter chars, and (if
+ * required), create the new argv item with the remaining text, and
+ * add it to the argv list, after top_word.
+ */
+static void process_split(struct grub2_script *script,
+ struct grub2_word *top_word,
+ struct grub2_word *word)
+{
+ int i, len, delim_start = -1, delim_end = -1;
+ struct grub2_word *new_word;
+ char *remainder;
+
+ len = strlen(word->text);
+
+ /* Scan our string for the start of a delim (delim_start), and the
+ * start of any new text (delim_end). */
+ for (i = 0; i < len; i++) {
+ if (is_delim(word->text[i])) {
+ if (delim_start == -1)
+ delim_start = i;
+ } else if (delim_start != -1) {
+ delim_end = i;
+ break;
+ }
+ }
+
+ /* No delim? nothing to do. The process_expansions loop will
+ * append this word's text to the top word, if necessary
+ */
+ if (delim_start == -1)
+ return;
+
+ /* Set this word's text value to the text before the delimiter.
+ * this will get appended to the top word
+ */
+ word->text[delim_start] = '\0';
+
+ /* No trailing text? If there are no following word tokens, we're done.
+ * Otherwise, we need to start a new argv item with those tokens */
+ if (delim_end == -1) {
+ if (!word->next)
+ return;
+ remainder = "";
+ } else {
+ remainder = word->text + delim_end;
+ }
+
+ new_word = talloc(script, struct grub2_word);
+ new_word->type = GRUB2_WORD_TEXT;
+ /* if there's no trailing text, we know we don't need to re-split */
+ new_word->split = delim_end != -1;
+ new_word->next = word->next;
+ new_word->last = NULL;
+ new_word->text = talloc_strdup(new_word, remainder);
+
+ /* stitch it into the argv list before this word */
+ list_insert_after(&top_word->argv_list,
+ &new_word->argv_list);
+
+ /* terminate this word */
+ word->next = NULL;
+}
+
+/* iterate through the words in an argv_list, looking for GRUB2_WORD_VAR
+ * expansions.
+ *
+ * Once that's done, we may (if split == true) have to split the word to create
+ * new argv items
+ */
+static void process_expansions(struct grub2_script *script,
+ struct grub2_argv *argv)
+{
+ struct grub2_word *top_word, *word;
+ int i;
+
+ argv->argc = 0;
+
+ list_for_each_entry(&argv->words, top_word, argv_list) {
+ argv->argc++;
+
+ /* expand vars and squash the list of words into the head
+ * of the argv word list */
+ for (word = top_word; word; word = word->next) {
+
+ /* if it's a variable, perform the substitution */
+ if (word->type == GRUB2_WORD_VAR) {
+ expand_var(script, word);
+ word->type = GRUB2_WORD_TEXT;
+ }
+
+ /* split; this will potentially insert argv
+ * entries after top_word. */
+ if (word->split)
+ process_split(script, top_word, word);
+
+ /* accumulate word text into the top word, so
+ * we end up with a shallow tree of argv data */
+ /* todo: don't do this in process_split */
+ if (word != top_word) {
+ top_word->text = talloc_asprintf_append(
+ top_word->text,
+ "%s", word->text);
+ }
+
+
+ }
+ top_word->next = NULL;
+ }
+
+ /* convert the list to an argv array, to pass to the function */
+ argv->argv = talloc_array(script, char *, argv->argc);
+ i = 0;
+
+ list_for_each_entry(&argv->words, word, argv_list)
+ argv->argv[i++] = word->text;
+}
+
+int statements_execute(struct grub2_script *script,
+ struct grub2_statements *stmts)
+{
+ struct grub2_statement *stmt;
+ int rc = 0;
+
+ list_for_each_entry(&stmts->list, stmt, list) {
+ if (stmt->exec)
+ rc = stmt->exec(script, stmt);
+ }
+ return rc;
+}
+
+int statement_simple_execute(struct grub2_script *script,
+ struct grub2_statement *statement)
+{
+ struct grub2_statement_simple *st = to_stmt_simple(statement);
+ struct grub2_command *cmd;
+ int rc;
+
+ if (!st->argv)
+ return 0;
+
+ process_expansions(script, st->argv);
+
+ if (!st->argv->argc)
+ return 0;
+
+ cmd = script_lookup_command(script, st->argv->argv[0]);
+ if (!cmd) {
+ fprintf(stderr, "undefined command '%s'\n", st->argv->argv[0]);
+ return 0;
+ }
+
+ rc = cmd->exec(script, st->argv->argc, st->argv->argv);
+
+ return rc;
+}
+
+int statement_if_execute(struct grub2_script *script,
+ struct grub2_statement *statement)
+{
+ struct grub2_statement_if *st = to_stmt_if(statement);
+ struct grub2_statements *case_stmts;
+ int rc;
+
+ rc = st->condition->exec(script, st->condition);
+
+ if (rc == 0)
+ case_stmts = st->true_case;
+ else
+ case_stmts = st->false_case;
+
+ if (case_stmts)
+ statements_execute(script, case_stmts);
+ else
+ rc = 0;
+
+ return rc;
+}
+
+int statement_menuentry_execute(struct grub2_script *script,
+ struct grub2_statement *statement)
+{
+ struct grub2_statement_menuentry *st = to_stmt_menuentry(statement);
+
+ process_expansions(script, st->argv);
+ statements_execute(script, st->statements);
+
+ return 0;
+}
+
+static void init_env(struct grub2_script *script)
+{
+ struct env_entry *env;
+
+ list_init(&script->environment);
+
+ env = talloc(script, struct env_entry);
+ env->name = talloc_strdup(env, "prefix");
+ env->value = talloc_strdup(env, "/");
+
+ list_add(&script->environment, &env->list);
+}
+
+struct grub2_command *script_lookup_command(struct grub2_script *script,
+ const char *name)
+{
+ struct grub2_command *command;
+
+ list_for_each_entry(&script->commands, command, list) {
+ if (!strcmp(command->name, name))
+ return command;
+ }
+
+ return NULL;
+}
+
+void script_register_command(struct grub2_script *script,
+ struct grub2_command *command)
+{
+ list_add(&script->commands, &command->list);
+}
+
+
+void script_execute(struct grub2_script *script)
+{
+ statements_execute(script, script->statements);
+}
+