]> git.ozlabs.org Git - petitboot/blobdiff - discover/grub2/script.c
discover/grub2: Allow using title for default even if id was defined
[petitboot] / discover / grub2 / script.c
index fce4f0afde487f8fc623ccc2ab519bf2d4ecee0e..c910bf8bc1a28bf86901459b11d7a99ad059bc35 100644 (file)
@@ -1,24 +1,57 @@
 
 #include <sys/types.h>
 #include <string.h>
+#include <stdlib.h>
 
+#include <log/log.h>
+#include <types/types.h>
 #include <talloc/talloc.h>
 
 #include "grub2.h"
 
 #define to_stmt_simple(stmt) \
        container_of(stmt, struct grub2_statement_simple, st)
+#define to_stmt_block(stmt) \
+       container_of(stmt, struct grub2_statement_block, 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_for(stmt) \
+       container_of(stmt, struct grub2_statement_for, st)
+#define to_stmt_conditional(stmt) \
+       container_of(stmt, struct grub2_statement_conditional, st)
 
 struct env_entry {
+       char                    *name;
+       char                    *value;
+       struct list_item        list;
+};
+
+struct grub2_symtab_entry {
        const char              *name;
-       const char              *value;
+       grub2_function          fn;
+       void                    *data;
        struct list_item        list;
 };
 
+static const char *default_prefix = "/boot/grub";
+
+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;
@@ -44,68 +77,159 @@ void script_env_set(struct grub2_script *script,
 
        if (!entry) {
                entry = talloc(script, struct env_entry);
-               entry->name = name;
+               entry->name = talloc_strdup(entry, name);
                list_add(&script->environment, &entry->list);
+       } else {
+               talloc_free(entry->value);
        }
 
-       entry->value = value;
+       entry->value = talloc_strdup(entry, value);
 }
 
-static bool expand_var(struct grub2_script *script, struct grub2_word *word)
+static char *expand_var(struct grub2_script *script, struct grub2_word *word)
 {
        const char *val;
 
-       val = script_env_get(script, word->var.name);
+       val = script_env_get(script, word->name);
        if (!val)
                val = "";
 
-       word->type = GRUB2_WORD_TEXT;
-       word->text = talloc_strdup(script, val);
+       return talloc_strdup(script, val);
+}
 
-       return true;
+static bool is_delim(char c)
+{
+       return c == ' ' || c == '\t';
 }
 
-/* iterate through the words in an argv_list, looking for GRUB2_WORD_VAR
+static bool option_is_default(struct grub2_script *script,
+                             struct discover_boot_option *opt, const char *id)
+{
+       unsigned int default_idx;
+       const char *var;
+       char *end;
+
+       var = script_env_get(script, "default");
+       if (!var)
+               return false;
+
+       default_idx = strtoul(var, &end, 10);
+       if (end != var && *end == '\0')
+               return default_idx == script->n_options;
+
+       if (id && !strcmp(id, var))
+               return true;
+
+       return !strcmp(opt->option->name, var);
+}
+
+static void append_text_to_current_arg(struct grub2_argv *argv,
+               const char *text, int len)
+{
+       char *cur = argv->argv[argv->argc - 1];
+
+       if (cur) {
+               int curlen = strlen(cur);
+               cur = talloc_realloc(argv->argv, cur, char, len + curlen + 1);
+               memcpy(cur + curlen, text, len);
+               cur[len + curlen] = '\0';
+
+       } else {
+               cur = talloc_strndup(argv->argv, text, len);
+       }
+
+       argv->argv[argv->argc-1] = cur;
+}
+
+/* Add a word to the argv array. Depending on the word type, and presence of
+ * delimiter characters, we may add multiple items to the array.
+ */
+static void append_word_to_argv(struct grub2_script *script,
+               struct grub2_argv *argv, struct grub2_word *word)
+{
+       const char *text, *pos;
+       int i, len;
+
+       /* If it's a variable, perform substitution */
+       if (word->type == GRUB2_WORD_VAR)
+               text = expand_var(script, word);
+       else
+               text = word->text;
+
+       len = strlen(text);
+
+       /* If we have no text, we leave the current word as-is. The caller
+        * has allocated an empty string for the case where this is the
+        * first text token */
+       if (!len)
+               return;
+
+       /* If we're not splitting, we just add the entire block to the
+        * current argv item */
+       if (!word->split) {
+               append_text_to_current_arg(argv, text, len);
+               return;
+       }
+
+       /* Scan for delimiters. If we find a word-end boundary, add the word
+        * to the argv array, and start a new argv item */
+       pos = !is_delim(text[0]) ? text : NULL;
+       for (i = 0; i < len; i++) {
+
+               /* first delimiter after a word: add the accumulated word to
+                * argv */
+               if (pos && is_delim(text[i])) {
+                       append_text_to_current_arg(argv, pos,
+                                       text + i - pos);
+                       pos = NULL;
+
+               /* first non-delimeter after a delimiter: record the starting
+                * position, and create another argv item */
+               } else if (!pos && !is_delim(text[i])) {
+                       pos = text + i;
+                       argv->argc++;
+                       argv->argv = talloc_realloc(argv, argv->argv, char *,
+                                       argv->argc);
+                       argv->argv[argv->argc - 1] = NULL;
+               }
+       }
+
+       /* add remaining word characters */
+       if (pos)
+               append_text_to_current_arg(argv, pos, text + len - pos);
+}
+
+/* Transform an argv word-token list (returned from the parser) into an
+ * expanded argv array (as used by the script execution code). We do this by
+ * iterating 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;
+       argv->argv = NULL;
 
        list_for_each_entry(&argv->words, top_word, argv_list) {
                argv->argc++;
-
-               /* expand vars and squash the list of words into the top struct.
-                * todo: splitting
-                */
-               for (word = top_word; word; word = word->next) {
-                       if (word->type == GRUB2_WORD_VAR)
-                               expand_var(script, word);
-
-                       if (word == top_word)
-                               continue;
-
-                       top_word->text = talloc_asprintf_append(top_word->text,
-                                       "%s", word->text);
-               }
-               top_word->next = NULL;
+               argv->argv = talloc_realloc(argv, argv->argv, char *,
+                               argv->argc);
+               /* because we've parsed a separate word here, we know that
+                * we need at least an empty string */
+               argv->argv[argv->argc - 1] = talloc_strdup(argv->argv, "");
+
+               for (word = top_word; word; word = word->next)
+                       append_word_to_argv(script, argv, word);
        }
 
-       argv->argv = talloc_array(script, char *, argv->argc);
-       i = 0;
-
-       list_for_each_entry(&argv->words, word, argv_list)
-               argv->argv[i++] = word->text;
+       /* we may have allocated an extra argv element but not populated it */
+       if (argv->argv && !argv->argv[argv->argc - 1])
+               argv->argc--;
 }
 
-int statements_execute(struct grub2_script *script,
+static int statements_execute(struct grub2_script *script,
                struct grub2_statements *stmts)
 {
        struct grub2_statement *stmt;
@@ -122,7 +246,8 @@ 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;
+       struct grub2_symtab_entry *entry;
+       char *pos;
        int rc;
 
        if (!st->argv)
@@ -133,35 +258,67 @@ int statement_simple_execute(struct grub2_script *script,
        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]);
+       /* is this a var=value assignment? */
+       pos = strchr(st->argv->argv[0], '=');
+       if (pos) {
+               char *name, *value;
+               name = st->argv->argv[0];
+               name = talloc_strndup(st, name, pos - name);
+               value = pos + 1;
+               script_env_set(script, name, value);
                return 0;
        }
 
-       rc = cmd->exec(script, st->argv->argc, st->argv->argv);
+       entry = script_lookup_function(script, st->argv->argv[0]);
+       if (!entry) {
+               pb_log("grub2: undefined function '%s'\n", st->argv->argv[0]);
+               return 1;
+       }
+
+       rc = entry->fn(script, entry->data, st->argv->argc, st->argv->argv);
 
        return rc;
 }
 
-int statement_if_execute(struct grub2_script *script,
+int statement_block_execute(struct grub2_script *script,
                struct grub2_statement *statement)
 {
-       struct grub2_statement_if *st = to_stmt_if(statement);
-       struct grub2_statements *case_stmts;
+       struct grub2_statement_block *st = to_stmt_block(statement);
+       return statements_execute(script, st->statements);
+}
+
+/* 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);
 
-       if (rc == 0)
-               case_stmts = st->true_case;
-       else
-               case_stmts = st->false_case;
+       return rc;
+}
 
-       if (case_stmts)
-               statements_execute(script, case_stmts);
-       else
-               rc = 0;
+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 = false;
+       int rc = 0;
+
+       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;
 }
@@ -170,59 +327,193 @@ 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;
+       const char *id = NULL;
+       int i;
 
        process_expansions(script, st->argv);
+
+       opt = discover_boot_option_create(script->ctx, script->ctx->device);
+
+       /* XXX: --options=values need to be parsed properly; this is a simple
+        * implementation to get --id= working.
+        */
+       for (i = 1; i < st->argv->argc; ++i) {
+               if (strncmp("--id=", st->argv->argv[i], 5) == 0) {
+                       id = st->argv->argv[i] + 5;
+                       break;
+               }
+       }
+       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,
+                       id ? id : opt->option->name);
+
+       script->opt = opt;
+
        statements_execute(script, st->statements);
 
+       if (!opt->boot_image)
+               return -1;
+
+       opt->option->is_default = option_is_default(script, opt, id);
+
+       list_add_tail(&script->options, &opt->list);
+       script->n_options++;
+       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 = 1; 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)
+               name = expand_var(script, st->name);
+       else
+               name = st->name->text;
+
+       script_register_function(script, name, function_invoke, st);
+
        return 0;
 }
 
+int statement_for_execute(struct grub2_script *script,
+               struct grub2_statement *statement)
+{
+       struct grub2_statement_for *st = to_stmt_for(statement);
+       const char *varname;
+       int i, rc = 0;
+
+       if (st->var->type == GRUB2_WORD_VAR)
+               expand_var(script, st->var);
+       varname = st->var->text;
+
+       process_expansions(script, st->list);
+
+       for (i = 0; i < st->list->argc; ++i) {
+               script_env_set(script, varname, st->list->argv[i]);
+               rc = statements_execute(script, st->body);
+       }
+
+       return rc;
+}
+
 static void init_env(struct grub2_script *script)
 {
        struct env_entry *env;
+       char *prefix, *sep;
 
        list_init(&script->environment);
 
+       /* use location of the parsed config file to determine the prefix */
        env = talloc(script, struct env_entry);
-       env->name = talloc_strdup(env, "prefix");
-       env->value = talloc_strdup(env, "/");
 
-       list_add(&script->environment, &env->list);
+       prefix = NULL;
+       if (script->filename) {
+               sep = strrchr(script->filename, '/');
+               if (sep)
+                       prefix = talloc_strndup(env, script->filename,
+                                       sep - script->filename);
+       }
+
+       script_env_set(script, "prefix", prefix ? : default_prefix);
+       if (prefix)
+               talloc_free(prefix);
+
+       /* establish feature settings */
+       script_env_set(script, "feature_menuentry_id", "y");
 }
 
-struct grub2_command *script_lookup_command(struct grub2_script *script,
-               const char *name)
+void script_register_function(struct grub2_script *script,
+               const char *name, grub2_function fn,
+               void *data)
 {
-       struct grub2_command *command;
-
-       list_for_each_entry(&script->commands, command, list) {
-               if (!strcmp(command->name, name))
-                       return command;
-       }
+       struct grub2_symtab_entry *entry;
 
-       return NULL;
+       entry = talloc(script, struct grub2_symtab_entry);
+       entry->fn = fn;
+       entry->name = name;
+       entry->data = data;
+       list_add(&script->symtab, &entry->list);
 }
 
-void script_register_command(struct grub2_script *script,
-               struct grub2_command *command)
+static void set_fallback_default(struct grub2_script *script)
 {
-       list_add(&script->commands, &command->list);
-}
+       struct discover_boot_option *opt, *first = NULL;
+       bool have_default = false;
+
+       list_for_each_entry(&script->options, opt, list) {
+               if (!first)
+                       first = opt;
+               have_default = have_default || opt->option->is_default;
+       }
 
+       if (!have_default && first) {
+               const char *env = script_env_get(script, "default");
+
+               pb_log("grub: no explicit default (env default=%s), "
+                               "falling back to first option (%s)\n",
+                               env ?: "unset", first->option->name);
+
+               first->option->is_default = true;
+       }
+}
 
 void script_execute(struct grub2_script *script)
 {
+       struct discover_boot_option *opt, *tmp;
+
+       if (!script)
+               return;
+
+       init_env(script);
        statements_execute(script, script->statements);
+
+       set_fallback_default(script);
+
+       list_for_each_entry_safe(&script->options, opt, tmp, list)
+               discover_context_add_boot_option(script->ctx, opt);
+
+       /* Our option list will be invalid, as we've added all options to the
+        * discover context */
+       list_init(&script->options);
 }
 
-struct grub2_script *create_script(void *ctx)
+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_zero(parser, struct grub2_script);
 
-       init_env(script);
-       list_init(&script->commands);
+       script->ctx = ctx;
+
+       list_init(&script->symtab);
+       list_init(&script->options);
        register_builtins(script);
 
        return script;