[U-Boot] [PATCH v4 6/7] env: make "env default" selective, check and apply

[Marek Vasut <marek.vasut@gmail.com>]

Dear Gerlando Falauto,

> Change the syntax (user API) for "env default":
>   -f: override write-once variables
>   var... : accept individual variable(s)
>   -a: all (resetting the whole env is NOT the default behavior)
> 
> Enable variable checking and make changes effective by
> enabling do_apply argument to himport_r().
> 
> Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
> ---
>  common/cmd_nvedit.c   |   40 ++++++++++++++++++++++++++++++++++------
>  common/env_common.c   |   28 +++++++++++++++++++++++++++-
>  include/environment.h |    3 +++
>  3 files changed, 64 insertions(+), 7 deletions(-)
> 
> diff --git a/common/cmd_nvedit.c b/common/cmd_nvedit.c
> index b0860f3..ac2b985 100644
> --- a/common/cmd_nvedit.c
> +++ b/common/cmd_nvedit.c
> @@ -656,14 +656,41 @@ int envmatch(uchar *s1, int i2)
>  	return -1;
>  }
> 
> -static int do_env_default(cmd_tbl_t *cmdtp, int flag,
> +static int do_env_default(cmd_tbl_t *cmdtp, int __flag,
>  			  int argc, char * const argv[])
>  {
> -	if (argc != 2 || strcmp(argv[1], "-f") != 0)
> -		return CMD_RET_USAGE;
> +	int all = 0, flag = 0;
> 
> -	set_default_env("## Resetting to default environment\n");
> -	return 0;
> +	debug("Initial value for argc=%d\n", argc);
> +	while (--argc > 0 && **++argv == '-') {

mmmmm ... **++argv, yummy :) This might use some cleanup, to make more readable. 
Don't we have some getopt or something too ?

> +		char *arg = *argv;
> +
> +		while (*++arg) {
> +			switch (*arg) {
> +			case 'a':		/* default all */
> +				all = 1;
> +				break;
> +			case 'f':		/* force */
> +				flag |= H_FORCE;
> +				break;
> +			default:
> +				return cmd_usage(cmdtp);
> +			}
> +		}
> +	}
> +	debug("Final value for argc=%d\n", argc);
> +	if (all && (argc == 0)) {
> +		/* Reset the whole environment */
> +		set_default_env("## Resetting to default environment\n");
> +		return 0;
> +	}
> +	if (!all && (argc > 0)) {
> +		/* Reset individual variables */
> +		set_default_vars(argc, argv);
> +		return 0;
> +	}
> +
> +	return cmd_usage(cmdtp);
>  }
> 
>  static int do_env_delete(cmd_tbl_t *cmdtp, int flag,
> @@ -994,7 +1021,8 @@ U_BOOT_CMD(
>  #if defined(CONFIG_CMD_ASKENV)
>  	"ask name [message] [size] - ask for environment variable\nenv "
>  #endif
> -	"default -f - reset default environment\n"
> +	"default [-f] -a - [forcibly] reset default environment\n"
> +	"env default [-f] var [...] - [forcibly] reset variable(s) to their
> default values\n" #if defined(CONFIG_CMD_EDITENV)
>  	"env edit name - edit environment variable\n"
>  #endif
> diff --git a/common/env_common.c b/common/env_common.c
> index c6e7c4c..482d715 100644
> --- a/common/env_common.c
> +++ b/common/env_common.c
> @@ -177,6 +177,11 @@ const uchar *env_get_addr(int index)
> 
>  void set_default_env(const char *s)
>  {
> +	/*
> +	 * By default, do not apply changes as they will eventually
> +	 * be applied by someone else
> +	 */
> +	int do_apply = 0;
>  	if (sizeof(default_environment) > ENV_SIZE) {
>  		puts("*** Error - default environment is too large\n\n");
>  		return;
> @@ -188,6 +193,14 @@ void set_default_env(const char *s)
>  				"using default environment\n\n",
>  				s + 1);
>  		} else {
> +			/*
> +			 * This set_to_default was explicitly asked for
> +			 * by the user, as opposed to being a recovery
> +			 * mechanism.  Therefore we check every single
> +			 * variable and apply changes to the system
> +			 * right away (e.g. baudrate, console).
> +			 */
> +			do_apply = 1;
>  			puts(s);
>  		}
>  	} else {
> @@ -196,12 +209,25 @@ void set_default_env(const char *s)
> 
>  	if (himport_r(&env_htab, (char *)default_environment,
>  			sizeof(default_environment), '\0', 0,
> -			0, NULL, 0 /* do_apply */) == 0)
> +			0, NULL, do_apply) == 0)
>  		error("Environment import failed: errno = %d\n", errno);
> 
>  	gd->flags |= GD_FLG_ENV_READY;
>  }
> 
> +
> +/* [re]set individual variables to their value in the default environment
> */ +int set_default_vars(int nvars, char * const vars[])
> +{
> +	/*
> +	 * Special use-case: import from default environment
> +	 * (and use \0 as a separator)
> +	 */
> +	return himport_r(&env_htab, (const char *)default_environment,
> +				sizeof(default_environment), '\0', H_NOCLEAR,
> +				nvars, vars, 1 /* do_apply */);
> +}
> +
>  /*
>   * Check if CRC is valid and (if yes) import the environment.
>   * Note that "buf" may or may not be aligned.
> diff --git a/include/environment.h b/include/environment.h
> index 90fb130..e8ab703 100644
> --- a/include/environment.h
> +++ b/include/environment.h
> @@ -181,6 +181,9 @@ void env_crc_update(void);
>  /* [re]set to the default environment */
>  void set_default_env(const char *s);
> 
> +/* [re]set individual variables to their value in the default environment
> */ +int set_default_vars(int nvars, char * const vars[]);
> +
>  /* Import from binary representation into hash table */
>  int env_import(const char *buf, int check);

Best regards,
Marek Vasut