discover/grub: Add blscfg command support to parse BootLoaderSpec files

The BootLoaderSpec (BLS) defines a file format for boot configurations,
so bootloaders can parse these files and create their boot menu entries
by using the information provided by them [0].

This allow to configure the boot items as drop-in files in a directory
instead of having to parse and modify a bootloader configuration file.

The GRUB 2 bootloader provides a blscfg command that parses these files
and creates menu entries using this information. Add support for it.

[0]: https://www.freedesktop.org/wiki/Specifications/BootLoaderSpec/

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/discover/parser.c b/discover/parser.c
index 5598f96..9fe1925 100644
--- a/discover/parser.c
+++ b/discover/parser.c
@@ -128,6 +128,22 @@ out:
 	return -1;
 }
 
+int parser_scandir(struct discover_context *ctx, const char *dirname,
+		   struct dirent ***files, int (*filter)(const struct dirent *),
+		   int (*comp)(const struct dirent **, const struct dirent **))
+{
+	char *path;
+	int n;
+
+	path = talloc_asprintf(ctx, "%s%s", ctx->device->mount_path, dirname);
+	if (!path)
+		return -1;
+
+	n = scandir(path, files, filter, comp);
+	talloc_free(path);
+	return n;
+}
+
 void iterate_parsers(struct discover_context *ctx)
 {
 	struct p_item* i;