Re: [PATCH] environment: add new global.env.noload parameter

[Sascha Hauer <s.hauer@pengutronix.de>]

On Mon, Dec 01, 2025 at 10:42:56AM +0100, Ahmad Fatoum wrote:
> Hi,
> 
> On 12/1/25 10:37 AM, Sascha Hauer wrote:
> > On Fri, Nov 28, 2025 at 06:21:14PM +0100, Ahmad Fatoum wrote:
> >> It can be useful for board code to deny loading an environment without
> >> disabling it altogether, e.g. to disable load of the environment when
> >> entering a recovery mode. Add a global variable that allows for just
> >> that.
> >>
> >> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> >> ---
> >>  common/environment.c | 8 +++++++-
> >>  1 file changed, 7 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/common/environment.c b/common/environment.c
> >> index d7f5f51cfc6d..d49f255ef007 100644
> >> --- a/common/environment.c
> >> +++ b/common/environment.c
> >> @@ -54,6 +54,7 @@ struct action_data {
> >>  #define TMPDIR "/.defaultenv"
> >>  
> >>  static int global_env_autoprobe = IS_ENABLED(CONFIG_INSECURE);
> >> +static int global_env_noload = false;
> >>  static char *default_environment_path;
> >>  
> >>  void default_environment_path_set(const char *path)
> >> @@ -455,7 +456,7 @@ int envfs_load(const char *filename, const char *dir, unsigned flags)
> >>  	size_t size, rsize;
> >>  
> >>  #ifdef __BAREBOX__
> >> -	if (!IS_ALLOWED(SCONFIG_ENVIRONMENT_LOAD))
> >> +	if (!IS_ALLOWED(SCONFIG_ENVIRONMENT_LOAD) || global_env_noload)
> >>  		return -EPERM;
> > 
> > With this you forbid to ever load an environment. The commit message
> > suggests you are looking for a way to skip loading of the environment,
> > so I would rather expect the check in the caller in common/startup.c
> 
> Well, a user could change the value of the variable later, but I agree
> checking in common/startup.c makes more sense.
> 
> > 
> >>  #ifdef __BAREBOX__
> >> +
> >>  static int register_env_vars(void)
> >>  {
> >>  	globalvar_add_simple_bool("env.autoprobe", &global_env_autoprobe);
> >> +	globalvar_add_simple_bool("env.noload", &global_env_noload);
> > 
> > globalvars are usually meant for variables that are set/read from the
> > shell. What's your usecase for setting this from shell?
> 
> This is supposed to set by board code. Shell would be too late.
> 
> > Having this as globalvar implies there is a corresponding nvvar. If I
> > read the code correctly then setting nv.env.noload=true in the builtin
> > default environment will not have the effect that loading of the
> > persistent environment is suppressed. Setting nv.env.noload=true in the
> > persistent environment obviously also isn't meaningful. The only effect
> > will be that a loadenv command no longer works.
> > 
> > Making this a globalvar seems rather confusing to me.
> 
> So you prefer I turn this into a function instead?

Yes please.

Sascha

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