add example usage to hello command

script/argv.c

@@ -52,8 +52,17 @@ grub_script_argv_free (struct grub_script_argv *argv)
       grub_free (argv->args);
     }
 
+  if (argv->scripts)
+    {
+      for (i = 0; i < argv->argc; i++)
+	grub_script_free (argv->scripts[i]);
+
+      grub_free (argv->scripts);
+    }
+
   argv->argc = 0;
   argv->args = 0;
+  argv->scripts = 0;
 }
 
 /* Prepare for next argc.  */
@@ -61,20 +70,33 @@ int
 grub_script_argv_next (struct grub_script_argv *argv)
 {
   char **p = argv->args;
+  struct grub_script **q = argv->scripts;
 
-  if (argv->args && argv->args[argv->argc - 1] == 0)
+  if (argv->args && argv->argc && argv->args[argv->argc - 1] == 0)
     return 0;
 
   p = grub_realloc (p, round_up_exp ((argv->argc + 2) * sizeof (char *)));
   if (! p)
     return 1;
 
+  q = grub_realloc (q, round_up_exp ((argv->argc + 2) * sizeof (struct grub_script *)));
+  if (! q)
+    {
+      grub_free (p);
+      return 1;
+    }
+
   argv->argc++;
   argv->args = p;
+  argv->scripts = q;
 
   if (argv->argc == 1)
-    argv->args[0] = 0;
+    {
+      argv->args[0] = 0;
+      argv->scripts[0] = 0;
+    }
   argv->args[argv->argc] = 0;
+  argv->scripts[argv->argc] = 0;
   return 0;
 }
 
@@ -100,6 +122,25 @@ grub_script_argv_append (struct grub_script_argv *argv, const char *s)
   return 0;
 }
 
+/* Append grub_script `s' as the last argument.  */
+int
+grub_script_argv_script_append (struct grub_script_argv *argv,
+				struct grub_script *script)
+{
+  struct grub_script *s;
+
+  s = grub_malloc (sizeof (*s));
+  if (! s)
+    return 1;
+
+  if (argv->scripts[argv->argc - 1])
+    grub_script_free (argv->scripts[argv->argc - 1]);
+
+  *s = *script;
+  argv->scripts[argv->argc - 1] = s;
+  return 0;
+}
+
 /* Split `s' and append words as multiple arguments.  */
 int
 grub_script_argv_split_append (struct grub_script_argv *argv, char *s)

script/execute.c

@@ -25,6 +25,7 @@
 #include <grub/menu.h>
 #include <grub/lib/arg.h>
 #include <grub/normal.h>
+#include <grub/extcmd.h>
 
 /* Max digits for a char is 3 (0xFF is 255), similarly for an int it
    is sizeof (int) * 3, and one extra for a possible -ve sign.  */
@@ -51,7 +52,7 @@ grub_env_special (const char *name)
 static char **
 grub_script_env_get (const char *name, grub_script_arg_type_t type)
 {
-  struct grub_script_argv result = { 0, 0 };
+  struct grub_script_argv result = { 0, 0, 0 };
 
   if (grub_script_argv_next (&result))
     goto fail;
@@ -169,7 +170,7 @@ grub_script_arglist_to_argv (struct grub_script_arglist *arglist,
   int i;
   char **values = 0;
   struct grub_script_arg *arg = 0;
-  struct grub_script_argv result = { 0, 0 };
+  struct grub_script_argv result = { 0, 0, 0 };
 
   for (; arglist && arglist->arg; arglist = arglist->next)
     {
@@ -196,6 +197,11 @@ grub_script_arglist_to_argv (struct grub_script_arglist *arglist,
 	      break;
 
 	    case GRUB_SCRIPT_ARG_TYPE_BLOCK:
+	      if (grub_script_argv_append (&result, arg->str) ||
+		  grub_script_argv_script_append (&result, &arg->block))
+		goto fail;
+	      break;
+
 	    case GRUB_SCRIPT_ARG_TYPE_TEXT:
 	      if (grub_strlen (arg->str) &&
 		  grub_script_argv_append (&result, arg->str))
@@ -270,7 +276,7 @@ grub_script_execute_cmdline (struct grub_script_cmd *cmd)
   grub_script_function_t func = 0;
   char errnobuf[18];
   char *cmdname;
-  struct grub_script_argv argv = { 0, 0 };
+  struct grub_script_argv argv = { 0, 0, 0 };
 
   /* Lookup the command.  */
   if (grub_script_arglist_to_argv (cmdline->arglist, &argv))
@@ -314,7 +320,14 @@ grub_script_execute_cmdline (struct grub_script_cmd *cmd)
 
   /* Execute the GRUB command or function.  */
   if (grubcmd)
-    ret = (grubcmd->func) (grubcmd, argv.argc - 1, argv.args + 1);
+    {
+      if ((grubcmd->flags & GRUB_COMMAND_FLAG_BLOCKS) &&
+	  (grubcmd->flags & GRUB_COMMAND_FLAG_EXTCMD))
+	ret = grub_extcmd_dispatcher (grubcmd, argv.argc - 1, argv.args + 1,
+				      argv.scripts + 1);
+      else
+	ret = (grubcmd->func) (grubcmd, argv.argc - 1, argv.args + 1);
+    }
   else
     ret = grub_script_function_call (func, argv.argc - 1, argv.args + 1);
 
@@ -374,7 +387,7 @@ grub_script_execute_cmdfor (struct grub_script_cmd *cmd)
 {
   unsigned i;
   grub_err_t result;
-  struct grub_script_argv argv = { 0, 0 };
+  struct grub_script_argv argv = { 0, 0, 0 };
   struct grub_script_cmdfor *cmdfor = (struct grub_script_cmdfor *) cmd;
 
   if (grub_script_arglist_to_argv (cmdfor->words, &argv))
@@ -416,7 +429,7 @@ grub_err_t
 grub_script_execute_menuentry (struct grub_script_cmd *cmd)
 {
   struct grub_script_cmd_menuentry *cmd_menuentry;
-  struct grub_script_argv argv = { 0, 0 };
+  struct grub_script_argv argv = { 0, 0, 0 };
 
   cmd_menuentry = (struct grub_script_cmd_menuentry *) cmd;
 

script/parser.y

@@ -164,7 +164,7 @@ block: "{"
          if ((p = grub_script_lexer_record_stop (state, $<offset>2)))
 	   *grub_strrchr (p, '}') = '\0';
 
-         if (arg = grub_script_arg_add (state, 0, GRUB_SCRIPT_ARG_TYPE_BLOCK, p))
+         if ((arg = grub_script_arg_add (state, 0, GRUB_SCRIPT_ARG_TYPE_BLOCK, p)))
 	   {
 	     arg->block.cmd = $3;
 	     arg->block.mem = memory;

script/script.c

@@ -96,7 +96,10 @@ grub_script_free (struct grub_script *script)
 {
   if (!script)
     return;
-  grub_script_mem_free (script->mem);
+
+  if (script->mem)
+    grub_script_mem_free (script->mem);
+
   grub_free (script);
 }
 
@@ -119,6 +122,9 @@ grub_script_arg_add (struct grub_parser_param *state,
     return arg;
 
   argpart->type = type;
+  argpart->block.mem = 0;
+  argpart->block.cmd = 0;
+
   len = grub_strlen (str) + 1;
   argpart->str = grub_script_malloc (state, len);
   if (!argpart->str)