Re: [PATCH v0] Require human interaction to go to normal shell if grub.cfg has a problem

[Andrey Borzenkov <arvidjaar@gmail.com>]

В Mon, 25 Nov 2013 15:46:48 -0800
Jon McCune <jonmccune@google.com> пишет:

> The rescue prompt is very useful for human operators, but not so
> useful in unattended environments.  Add a facility for rebooting
> after a delay, so that, e.g., the system can still PXE boot if
> there is no console attached.
> 
> Signed-off-by: Jon McCune <jonmccune@google.com>
> ---
>  grub-core/normal/main.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/grub-core/normal/main.c b/grub-core/normal/main.c

You get rescue prompt when you can *not* launch normal.mod. 

> index ad36273..f8953d5 100644
> --- a/grub-core/normal/main.c
> +++ b/grub-core/normal/main.c
> @@ -32,6 +32,7 @@
>  #include <grub/i18n.h>
>  #include <grub/charset.h>
>  #include <grub/script_sh.h>
> +#include <grub/time.h>
>  
>  GRUB_MOD_LICENSE ("GPLv3+");
>  
> @@ -333,6 +334,21 @@ grub_normal_execute (const char *config, int nested, int batch)
>      }
>  }
>  
> +/* Copied from grub-core/commands/sleep.c. */
> +static int
> +grub_interruptible_millisleep (grub_uint32_t ms)
> +{
> +  grub_uint64_t start;
> +
> +  start = grub_get_time_ms ();
> +
> +  while (grub_get_time_ms () - start < ms)
> +    if (grub_getkey_noblock () == GRUB_TERM_ESC)
> +      return 1;
> +
> +  return 0;
> +}
> +
>  /* This starts the normal mode.  */
>  void
>  grub_enter_normal_mode (const char *config)
> @@ -340,6 +356,15 @@ grub_enter_normal_mode (const char *config)
>    grub_boot_time ("Entering normal mode");
>    nested_level++;
>    grub_normal_execute (config, 0, 0);
> +  /* Control only returns from grub_normal_execute() if there is some kind of
> +   * problem with grub.cfg, like it does not exist.  Reboot by default unless
> +   * ESC is pressed within 5 seconds. */

grub-mkrescue creates CD that starts normal CLI without grub.cfg. So
please - not as default. You can make it dependent on variable which
can be set in embedded grub.cfg for the cases when you really need it.

> +  grub_printf ("Press ESC in 5 seconds for a rescue shell.\n");

"for a command line". This is not rescue shell.

> +  if (!grub_interruptible_millisleep (5000))
> +    {
> +      grub_printf ("Rebooting instead of going to rescue shell.\n");

Ditto.

> +      grub_reboot ();
> +    }
>    grub_boot_time ("Entering shell");
>    grub_cmdline_run (0);
>    nested_level--;