]> git.ozlabs.org Git - petitboot/blobdiff - discover/grub2/script.c
discover/grub2: Add a reference to the context from grub2_script
[petitboot] / discover / grub2 / script.c
index b6d3221c36effed793300a63af86d34a44475dfa..5b38156822b5f6083eb59fe1bd74a60a6ec7b829 100644 (file)
@@ -1,6 +1,5 @@
 
 #include <sys/types.h>
-#include <regex.h>
 #include <string.h>
 
 #include <talloc/talloc.h>
@@ -11,6 +10,8 @@
        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;
@@ -18,51 +19,125 @@ struct env_entry {
        struct list_item        list;
 };
 
-static const char *env_lookup(struct grub2_script *script,
-               const char *name, int name_len)
+const char *script_env_get(struct grub2_script *script, const char *name)
 {
        struct env_entry *entry;
-       const char *str;
-
-       str = talloc_strndup(script, name, name_len);
-       printf("%s: %s\n", __func__, str);
 
        list_for_each_entry(&script->environment, entry, list)
-               if (!strncmp(entry->name, name, name_len))
+               if (!strcmp(entry->name, name))
                        return entry->value;
 
        return NULL;
 }
 
-static bool expand_word(struct grub2_script *script, struct grub2_word *word)
+void script_env_set(struct grub2_script *script,
+               const char *name, const char *value)
 {
-       const char *val, *src;
-       char *dest = NULL;
-       regmatch_t match;
-       int n;
+       struct env_entry *e, *entry = NULL;
 
-       src = word->text;
+       list_for_each_entry(&script->environment, e, list) {
+               if (!strcmp(e->name, name)) {
+                       entry = e;
+                       break;
+               }
+       }
 
-       n = regexec(&script->var_re, src, 1, &match, 0);
-       printf("%s %s: %d\n", __func__, word->text, n);
-       if (n != 0)
-               return false;
+       if (!entry) {
+               entry = talloc(script, struct env_entry);
+               entry->name = name;
+               list_add(&script->environment, &entry->list);
+       }
+
+       entry->value = value;
+}
 
-       val = env_lookup(script, src + match.rm_so,
-                                match.rm_eo - match.rm_so);
+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 = "";
 
-       dest = talloc_strndup(script, src, match.rm_so);
-       dest = talloc_asprintf_append(dest, "%s%s", val, src + match.rm_eo);
+       word->text = talloc_strdup(script, val);
 
-       word->text = dest;
        return true;
 }
 
-/* iterate through the words in an argv, looking for expansions. If a
- * word is marked with expand == true, then we process any variable
- * substitutions.
+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
@@ -70,17 +145,52 @@ static bool expand_word(struct grub2_script *script, struct grub2_word *word)
 static void process_expansions(struct grub2_script *script,
                struct grub2_argv *argv)
 {
-       struct grub2_word *word;
+       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);
+                       }
 
-       list_for_each_entry(&argv->words, word, argv_list) {
-               if (!word->expand)
-                       continue;
 
-               expand_word(script, word);
+               }
+               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,
+static int statements_execute(struct grub2_script *script,
                struct grub2_statements *stmts)
 {
        struct grub2_statement *stmt;
@@ -89,7 +199,6 @@ int statements_execute(struct grub2_script *script,
        list_for_each_entry(&stmts->list, stmt, list) {
                if (stmt->exec)
                        rc = stmt->exec(script, stmt);
-               printf("%s(%p)\n", __func__, stmt);
        }
        return rc;
 }
@@ -98,13 +207,26 @@ 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);
 
-       return 0;
+       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,
@@ -129,40 +251,67 @@ int statement_if_execute(struct grub2_script *script,
        return rc;
 }
 
+int statement_menuentry_execute(struct grub2_script *script,
+               struct grub2_statement *statement)
+{
+       struct grub2_statement_menuentry *st = to_stmt_menuentry(statement);
 
-void script_execute(struct grub2_script *script)
+       process_expansions(script, st->argv);
+       statements_execute(script, st->statements);
+
+       return 0;
+}
+
+static void init_env(struct grub2_script *script)
 {
-       statements_execute(script, script->statements);
+       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);
 }
 
-static int script_destroy(void *p)
+struct grub2_command *script_lookup_command(struct grub2_script *script,
+               const char *name)
 {
-       struct grub2_script *script = p;
-       regfree(&script->var_re);
-       return 0;
+       struct grub2_command *command;
+
+       list_for_each_entry(&script->commands, command, list) {
+               if (!strcmp(command->name, name))
+                       return command;
+       }
+
+       return NULL;
 }
 
-struct grub2_script *create_script(void *ctx)
+void script_register_command(struct grub2_script *script,
+               struct grub2_command *command)
 {
-       struct grub2_script *script;
-       int rc;
+       list_add(&script->commands, &command->list);
+}
 
-       script = talloc(ctx, struct grub2_script);
 
-       rc = regcomp(&script->var_re,
-               "\\$\\{?([[:alpha:]][_[:alnum:]]*|[0-9]|[\\?@\\*#])\\}?",
-                       REG_EXTENDED);
-       if (rc) {
-               char err[200];
-               regerror(rc, &script->var_re, err, sizeof(err));
-               fprintf(stderr, "RE error %d: %s\n", rc, err);
-               talloc_free(script);
-               return NULL;
+void script_execute(struct grub2_script *script)
+{
+       statements_execute(script, script->statements);
+}
 
-       }
-       talloc_set_destructor(script, script_destroy);
+struct grub2_script *create_script(struct grub2_parser *parser,
+               struct discover_context *ctx)
+{
+       struct grub2_script *script;
 
-       list_init(&script->environment);
+       script = talloc(parser, struct grub2_script);
+
+       init_env(script);
+       script->ctx = ctx;
+
+       list_init(&script->commands);
+       register_builtins(script);
 
        return script;
 }