[RFC PATCH] tools: env: Add an option to have an empty default environment

[Stefano Babic]

Hi Chris,

On 13.08.20 03:37, Chris Packham wrote:
> When building envtools via tools-only_defconfig the builtin defaults
> are based on options in the defconfig. For example:
> 
>   bootcmd=bootp; setenv bootargs root=/dev/nfs nfsroot=${serverip}:${rootpath} ip=${ipaddr}:${serverip}:${gatewayip}:${netmask}:${hostname}::off; bootm
>   bootdelay=2
>   baudrate=115200
>   stdin=serial,cros-ec-keyb,usbkbd
>   stdout=serial,vidconsole
>   stderr=serial,vidconsole
>   ethaddr=00:00:11:22:33:44
>   eth3addr=00:00:11:22:33:45
>   eth5addr=00:00:11:22:33:46
>   eth6addr=00:00:11:22:33:47
>   ipaddr=1.2.3.4
>   bootm_size=0x10000000
>   kernel_addr_r=0x1000000
>   fdt_addr_r=0xc00000
>   ramdisk_addr_r=0x2000000
>   scriptaddr=0x1000
>   pxefile_addr_r=0x2000
> 
> These may or may not be sensible for any particular target. Rather than
> trying to have a set of defaults that work for every target add a config
> option to make the default environment completely empty.
> 
> Signed-off-by: Chris Packham <judge.packham at gmail.com>
> ---

Which is the added value compared to use CONFIG_USE_DEFAULT_ENV_FILE=y
and adding your file with no variables ?

Best regards,
Stefano

> 
>  configs/tools-only_defconfig | 1 +
>  env/Kconfig                  | 7 +++++++
>  include/env_default.h        | 2 ++
>  3 files changed, 10 insertions(+)
> 
> diff --git a/configs/tools-only_defconfig b/configs/tools-only_defconfig
> index a853abf2b8fc..0ddd0518ef9a 100644
> --- a/configs/tools-only_defconfig
> +++ b/configs/tools-only_defconfig
> @@ -12,6 +12,7 @@ CONFIG_BOOTP_DNS2=y
>  CONFIG_OF_CONTROL=y
>  CONFIG_OF_HOSTFILE=y
>  CONFIG_SYS_RELOC_GD_ENV_ADDR=y
> +CONFIG_EMPTY_DEFAULT_ENV=y
>  CONFIG_BOOTP_SEND_HOSTNAME=y
>  CONFIG_IP_DEFRAG=y
>  # CONFIG_ACPIGEN is not set
> diff --git a/env/Kconfig b/env/Kconfig
> index af4d9cbaa4d8..f7860f01cc16 100644
> --- a/env/Kconfig
> +++ b/env/Kconfig
> @@ -614,6 +614,13 @@ config DEFAULT_ENV_FILE
>  	  containing key=value pairs, blank lines and lines beginning
>  	  with # are ignored.
>  
> +config EMPTY_DEFAULT_ENV
> +	bool "Create an empty default environment"
> +	help
> +	  Create an empty default environment. This is intended to be
> +	  used when building generic target tools and no sensible
> +	  default that can be included.
> +
>  config ENV_VARS_UBOOT_RUNTIME_CONFIG
>  	bool "Add run-time information to the environment"
>  	help
> diff --git a/include/env_default.h b/include/env_default.h
> index 8a0c3057f0aa..859188a8e7c9 100644
> --- a/include/env_default.h
> +++ b/include/env_default.h
> @@ -23,6 +23,7 @@ static char default_environment[] = {
>  const uchar default_environment[] = {
>  #endif
>  #ifndef CONFIG_USE_DEFAULT_ENV_FILE
> +#ifndef CONFIG_EMPTY_DEFAULT_ENV
>  #ifdef	CONFIG_ENV_CALLBACK_LIST_DEFAULT
>  	ENV_CALLBACK_VAR "=" CONFIG_ENV_CALLBACK_LIST_DEFAULT "\0"
>  #endif
> @@ -107,6 +108,7 @@ const uchar default_environment[] = {
>  #endif
>  #ifdef	CONFIG_EXTRA_ENV_SETTINGS
>  	CONFIG_EXTRA_ENV_SETTINGS
> +#endif
>  #endif
>  	"\0"
>  #else /* CONFIG_USE_DEFAULT_ENV_FILE */
> 


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