X-Git-Url: https://git.ozlabs.org/?p=petitboot;a=blobdiff_plain;f=discover%2Fgrub2%2Fscript.c;h=67b4b7801f8717d51df2cdbfc68edab97988f082;hp=71d6cba81a77cfabf37d2fc6bacfcf0d42092973;hb=882f61e8eb44ec9f9becc32328667c65f364d066;hpb=59747ee01e0158f97bdf8c182305e757d90a8d7a

diff --git a/discover/grub2/script.c b/discover/grub2/script.c
index 71d6cba..67b4b78 100644
--- a/discover/grub2/script.c
+++ b/discover/grub2/script.c
@@ -1,12 +1,400 @@
 
+#include <sys/types.h>
+#include <string.h>
+
+#include <types/types.h>
 #include <talloc/talloc.h>
 
 #include "grub2.h"
 
-struct grub2_script *create_script(void *ctx)
+#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)
+#define to_stmt_function(stmt) \
+	container_of(stmt, struct grub2_statement_function, st)
+#define to_stmt_conditional(stmt) \
+	container_of(stmt, struct grub2_statement_conditional, st)
+
+struct env_entry {
+	const char		*name;
+	const char		*value;
+	struct list_item	list;
+};
+
+struct grub2_symtab_entry {
+	const char		*name;
+	grub2_function		fn;
+	void			*data;
+	struct list_item	list;
+};
+
+static struct grub2_symtab_entry *script_lookup_function(
+		struct grub2_script *script, const char *name)
+{
+	struct grub2_symtab_entry *entry;
+
+	list_for_each_entry(&script->symtab, entry, list) {
+		if (!strcmp(entry->name, name))
+			return entry;
+	}
+
+	return NULL;
+}
+
+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;
+}
+
+static 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_symtab_entry *entry;
+	int rc;
+
+	if (!st->argv)
+		return 0;
+
+	process_expansions(script, st->argv);
+
+	if (!st->argv->argc)
+		return 0;
+
+	entry = script_lookup_function(script, st->argv->argv[0]);
+	if (!entry) {
+		fprintf(stderr, "undefined function '%s'\n", st->argv->argv[0]);
+		return 0;
+	}
+
+	rc = entry->fn(script, entry->data, st->argv->argc, st->argv->argv);
+
+	return rc;
+}
+
+/* returns 0 if the statement was executed, 1 otherwise */
+static int statement_conditional_execute(struct grub2_script *script,
+		struct grub2_statement *statement, bool *executed)
+{
+	struct grub2_statement_conditional *st = to_stmt_conditional(statement);
+	int rc;
+
+	rc = st->condition->exec(script, st->condition);
+	*executed = (!rc);
+	if (*executed)
+		rc = statements_execute(script, st->statements);
+
+	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_statement *conditional;
+	bool executed;
+	int rc;
+
+	list_for_each_entry(&st->conditionals->list, conditional, list) {
+		rc = statement_conditional_execute(script,
+				conditional, &executed);
+		if (executed)
+			break;
+	}
+
+	if (!executed && st->else_case)
+		rc = statements_execute(script, st->else_case);
+
+	return rc;
+}
+
+int statement_menuentry_execute(struct grub2_script *script,
+		struct grub2_statement *statement)
+{
+	struct grub2_statement_menuentry *st = to_stmt_menuentry(statement);
+	struct discover_boot_option *opt;
+
+	process_expansions(script, st->argv);
+
+	opt = discover_boot_option_create(script->ctx, script->ctx->device);
+	if (st->argv->argc > 0) {
+		opt->option->name = talloc_strdup(opt, st->argv->argv[0]);
+	} else {
+		opt->option->name = talloc_strdup(opt, "(unknown)");
+	}
+	opt->option->id = talloc_asprintf(opt->option, "%s#%s",
+			script->ctx->device->device->id,
+			opt->option->name);
+
+	script->opt = opt;
+
+	statements_execute(script, st->statements);
+
+	discover_context_add_boot_option(script->ctx, opt);
+	script->opt = NULL;
+
+	return 0;
+}
+
+static int function_invoke(struct grub2_script *script,
+		void *data, int argc, char **argv)
+{
+	struct grub2_statement_function *fn = data;
+	char *name;
+	int i;
+
+	/* set positional parameters */
+	for (i = 0; i < argc; i++) {
+		name = talloc_asprintf(script, "$%d", i);
+		script_env_set(script, name, argv[i]);
+	}
+
+	return statements_execute(script, fn->body);
+}
+
+int statement_function_execute(struct grub2_script *script,
+		struct grub2_statement *statement)
+{
+	struct grub2_statement_function *st = to_stmt_function(statement);
+	const char *name;
+
+	if (st->name->type == GRUB2_WORD_VAR)
+		expand_var(script, st->name);
+
+	name = st->name->text;
+	script_register_function(script, name, function_invoke, st);
+
+	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);
+}
+
+void script_register_function(struct grub2_script *script,
+		const char *name, grub2_function fn,
+		void *data)
+{
+	struct grub2_symtab_entry *entry;
+
+	entry = talloc(script, struct grub2_symtab_entry);
+	entry->fn = fn;
+	entry->name = name;
+	entry->data = data;
+	list_add(&script->symtab, &entry->list);
+}
+
+
+void script_execute(struct grub2_script *script)
+{
+	statements_execute(script, script->statements);
+}
+
+struct grub2_script *create_script(struct grub2_parser *parser,
+		struct discover_context *ctx)
 {
 	struct grub2_script *script;
-	script = talloc(ctx, struct grub2_script);
+
+	script = talloc(parser, struct grub2_script);
+
+	init_env(script);
+	script->ctx = ctx;
+	script->opt = NULL;
+
+	list_init(&script->symtab);
+	register_builtins(script);
+
 	return script;
 }