Re: New command eval.

[Seth Goldberg]

Hi,

  What about the feature environment variable to allow dynamic detection of 
this enhancement?

  --S

On May 11, 2013, at 9:35 AM, Andrey Borzenkov <address@hidden> wrote:

> В Sat, 04 May 2013 23:08:03 +0200
> Vladimir 'φ-coder/phcoder' Serbinenko <address@hidden> пишет:
> 
>>> - it adds "eval" command (same as known from UNIX shells) which
>>>  executes its argument
>> 
>> eval is generally good
>> 
>> 
>>> +static grub_err_t
>>> +grub_cmd_eval (grub_extcmd_context_t ctxt __attribute__((__unused__)),
>>> +           int argc, char *argv[])
>>> +{
>> 
>> You don't use any argument parsing. It's better to use command and not
>> extcmd in this case. Also "eval" in bash concatenates its arguments.
>> 
>>> +  cmd = grub_register_extcmd ("eval", grub_cmd_eval, 0,
>>> +                  N_("[STRING]"), N_("Evaluate commands"),
>> 
>> This description seems a bit vague for either human-reading or translation.
> 
> Is patch below OK? I decided to split off pure execute_sourcecode so
> that eval context would not clobber positional arguments.
> 
> diff --git a/ChangeLog b/ChangeLog
> index cd8213a..8ca9874 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,11 @@
> +2013-05-11  Andrey Borzenkov <address@hidden>
> +
> +    * grub-core/script/execute.c (grub_script_execute_sourcecode): Split
> +    off new function grub_script_execute_new_scope. Change callers to use
> +    either of them as appropriate.
> +    * grub-core/commands/eval.c: New command eval.
> +    * docs/grub.texi (Commands): Document it.
> +
> 2013-05-11  Vladimir Serbinenko  <address@hidden>
> 
>    * util/grub-install.in: Gettextize "Not found" message.
> diff --git a/docs/grub.texi b/docs/grub.texi
> index 75a5ea4..9dcfa2d 100644
> --- a/docs/grub.texi
> +++ b/docs/grub.texi
> @@ -3435,6 +3435,7 @@ you forget a command, you can run the command 
> @command{help}
> * date::                        Display or set current date and time
> * drivemap::                    Map a drive to another
> * echo::                        Display a line of text
> +* eval::                        Evaluate agruments as GRUB commands
> * export::                      Export an environment variable
> * false::                       Do nothing, unsuccessfully
> * gettext::                     Translate a string
> @@ -3812,6 +3813,15 @@ character will print that character.
> @end deffn
> 
> 
> address@hidden eval
> address@hidden eval
> +
> address@hidden Command eval string ...
> +Concatenate arguments together using single space as separator and evaluate
> +result as sequence of GRUB commands.
> address@hidden deffn
> +
> +
> @node export
> @subsection export
> 
> diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
> index 602b497..0fcc4e7 100644
> --- a/grub-core/Makefile.core.def
> +++ b/grub-core/Makefile.core.def
> @@ -699,6 +699,11 @@ module = {
> };
> 
> module = {
> +  name = eval;
> +  common = commands/eval.c;
> +};
> +
> +module = {
>   name = extcmd;
>   common = commands/extcmd.c;
>   common = lib/arg.c;
> diff --git a/grub-core/commands/eval.c b/grub-core/commands/eval.c
> new file mode 100644
> index 0000000..e514a1a
> --- /dev/null
> +++ b/grub-core/commands/eval.c
> @@ -0,0 +1,72 @@
> +/*
> + *  GRUB  --  GRand Unified Bootloader
> + *  Copyright (C) 2009  Free Software Foundation, Inc.
> + *
> + *  GRUB is free software: you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation, either version 3 of the License, or
> + *  (at your option) any later version.
> + *
> + *  GRUB is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <grub/dl.h>
> +#include <grub/misc.h>
> +#include <grub/script_sh.h>
> +#include <grub/command.h>
> +#include <grub/i18n.h>
> +#include <grub/term.h>
> +
> +GRUB_MOD_LICENSE ("GPLv3+");
> +
> +static grub_err_t
> +grub_cmd_eval (grub_command_t cmd __attribute__((__unused__)),
> +           int argc, char *argv[])
> +{
> +  int i;
> +  grub_size_t size = argc; /* +1 for final zero */
> +  char *str, *p;
> +  grub_err_t ret;
> +
> +  if (argc == 0)
> +    return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("missing arguments"));
> +
> +  for (i = 0; i < argc; i++)
> +    size += grub_strlen (argv[i]);
> +
> +  str = p = grub_malloc (size);
> +  if (!str)
> +    return grub_errno;
> +
> +  for (i = 0; i < argc; i++)
> +    {
> +      grub_strcpy (p, argv[i]);
> +      p += grub_strlen (argv[i]);
> +      *p++ = ' ';
> +    }
> +  *--p = '\0';
> +
> +  ret = grub_script_execute_sourcecode (str);
> +  grub_free (str);
> +  return ret;
> +}
> +
> +static grub_command_t cmd;
> +
> +GRUB_MOD_INIT(eval)
> +{
> +  cmd = grub_register_command ("eval", grub_cmd_eval, N_("STRING ..."),
> +                N_("Evaluate arguments as GRUB commands"));
> +}
> +
> +GRUB_MOD_FINI(eval)
> +{
> +  grub_unregister_command (cmd);
> +}
> +
> diff --git a/grub-core/normal/menu.c b/grub-core/normal/menu.c
> index fba19db..9b88290 100644
> --- a/grub-core/normal/menu.c
> +++ b/grub-core/normal/menu.c
> @@ -245,7 +245,7 @@ grub_menu_execute_entry(grub_menu_entry_t entry, int 
> auto_boot)
>   else
>     grub_env_unset ("default");
> 
> -  grub_script_execute_sourcecode (entry->sourcecode, entry->argc, 
> entry->args);
> +  grub_script_execute_new_scope (entry->sourcecode, entry->argc, 
> entry->args);
> 
>   if (errs_before != grub_err_printed_errors)
>     grub_wait_after_message ();
> diff --git a/grub-core/normal/menu_entry.c b/grub-core/normal/menu_entry.c
> index fae258a..0f15a7e 100644
> --- a/grub-core/normal/menu_entry.c
> +++ b/grub-core/normal/menu_entry.c
> @@ -1120,7 +1120,6 @@ run (struct screen *screen)
>   char *script;
>   int errs_before;
>   grub_menu_t menu = NULL;
> -  char *dummy[1] = { NULL };
> 
>   grub_cls ();
>   grub_printf ("  ");
> @@ -1160,7 +1159,7 @@ run (struct screen *screen)
>       }
>     script[size] = '\0';
>   }
> -  grub_script_execute_sourcecode (script, 0, dummy);
> +  grub_script_execute_sourcecode (script);
>   grub_free (script);
> 
>   if (errs_before != grub_err_printed_errors)
> diff --git a/grub-core/script/execute.c b/grub-core/script/execute.c
> index 9babbee..afd5513 100644
> --- a/grub-core/script/execute.c
> +++ b/grub-core/script/execute.c
> @@ -856,19 +856,10 @@ grub_script_execute_sourcecode_getline (char **line,
> 
> /* Execute a source script.  */
> grub_err_t
> -grub_script_execute_sourcecode (const char *source, int argc, char **args)
> +grub_script_execute_sourcecode (const char *source)
> {
>   grub_err_t ret = 0;
>   struct grub_script *parsed_script;
> -  struct grub_script_scope new_scope;
> -  struct grub_script_scope *old_scope;
> -
> -  new_scope.argv.argc = argc;
> -  new_scope.argv.args = args;
> -  new_scope.flags = 0;
> -
> -  old_scope = scope;
> -  scope = &new_scope;
> 
>   while (source)
>     {
> @@ -880,13 +871,35 @@ grub_script_execute_sourcecode (const char *source, int 
> argc, char **args)
>       if (! parsed_script)
>    {
>      ret = grub_errno;
> +      grub_free (line);
>      break;
>    }
> 
>       ret = grub_script_execute (parsed_script);
> +      grub_script_free (parsed_script);
>       grub_free (line);
>     }
> 
> +  return ret;
> +}
> +
> +/* Execute a source script in new scope.  */
> +grub_err_t
> +grub_script_execute_new_scope (const char *source, int argc, char **args)
> +{
> +  grub_err_t ret = 0;
> +  struct grub_script_scope new_scope;
> +  struct grub_script_scope *old_scope;
> +
> +  new_scope.argv.argc = argc;
> +  new_scope.argv.args = args;
> +  new_scope.flags = 0;
> +
> +  old_scope = scope;
> +  scope = &new_scope;
> +
> +  ret = grub_script_execute_sourcecode (source);
> +
>   scope = old_scope;
>   return ret;
> }
> diff --git a/include/grub/script_sh.h b/include/grub/script_sh.h
> index 78602e4..57bdd4d 100644
> --- a/include/grub/script_sh.h
> +++ b/include/grub/script_sh.h
> @@ -329,7 +329,8 @@ grub_err_t grub_script_execute_cmdwhile (struct 
> grub_script_cmd *cmd);
> 
> /* Execute any GRUB pre-parsed command or script.  */
> grub_err_t grub_script_execute (struct grub_script *script);
> -grub_err_t grub_script_execute_sourcecode (const char *source, int argc, 
> char **args);
> +grub_err_t grub_script_execute_sourcecode (const char *source);
> +grub_err_t grub_script_execute_new_scope (const char *source, int argc, char 
> **args);
> 
> /* Break command for loops.  */
> grub_err_t grub_script_break (grub_command_t cmd, int argc, char *argv[]);
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