[PATCH] blspec: derive root prefix from blspec config path instead of mountpoint

[Marco Felsch]

Hi,

thanks for your patch.

On 25-11-14, chalianis1 at gmail.com wrote:
> From: Chali Anis <chalianis1 at gmail.com>
> 
> Add get_prefix_path() to compute the filesystem prefix of a BLSpec
> entry by locating the deepest /loader/entries/ component in the

What exactly do you mean by "deepest"? The specification says that the
entries should be under /loader/entries of $BOOT or $EFI partition [1].

There is also a note:
"""""""""
In all cases the /loader/entries/ directory should be located directly
in the root of the ESP or XBOOTLDR filesystem. Specifically, the
/loader/entries/ directory should not be located under the /EFI/
subdirectory on the ESP.
"""""""""

So searching in subdirs seems not to be spec compatible. May I ask why
your loader entries are within some subdir in the first place?

Regards,
  Marco

[1] https://uapi-group.org/specifications/specs/boot_loader_specification/#type-1-boot-loader-specification-entries

> configuration path. This ensures correct rootpath extraction for
> nested loader directories, mixed path layouts, duplicate segments,
> and paths without valid loader entries. If no prefix is found,
> fall back to get_mounted_path().
> 
> Signed-off-by: Chali Anis <chalianis1 at gmail.com>
> ---
>  common/blspec.c | 25 ++++++++++++++++++++++++-
>  1 file changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/common/blspec.c b/common/blspec.c
> index 80ebe256ceaf..ad94d4d6be64 100644
> --- a/common/blspec.c
> +++ b/common/blspec.c
> @@ -391,6 +391,29 @@ static bool entry_is_match_machine_id(struct blspec_entry *entry)
>  	return ret;
>  }
>  
> +/*
> + * Return the path prefix before the deepest "/loader/entries/" component
> + * in @configname. Falls back to the mounted path if none is found.
> + */
> +static char *get_blspec_prefix_path(char *configname)
> +{
> +	char *p;
> +	char *scfg = configname;
> +	char *save = NULL;
> +
> +	while ((p = strstr(scfg, "/loader/entries/")) != NULL) {
> +		if (p - configname > 0)
> +			save = p;
> +
> +		scfg = p + 1;
> +	}
> +
> +	if (save && save - configname > 0)
> +		return xstrndup(configname, save - configname);
> +
> +	return get_mounted_path(configname);
> +}
> +
>  static int __blspec_scan_file(struct bootentries *bootentries, const char *root,
>  			      const char *configname)
>  {
> @@ -404,7 +427,7 @@ static int __blspec_scan_file(struct bootentries *bootentries, const char *root,
>  	if (IS_ERR(entry))
>  		return PTR_ERR(entry);
>  
> -	root = root ?: get_mounted_path(configname);
> +	root = root ?: get_blspec_prefix_path(configname);
>  	entry->rootpath = xstrdup_const(root);
>  	entry->configpath = xstrdup_const(configname);
>  	entry->cdev = get_cdev_by_mountpath(root);
> -- 
> 2.49.0
> 
> 
> 

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