fs: implement unreaddir

When iterating over a directory, it can be useful to put back the just
read directory entry, so it can be retried at a later time. This will be
needed for the EFI loader variable support.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.barebox.org/20221010061437.2085412-4-a.fatoum@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 15 insertions, 0 deletions

diff --git a/fs/fs.c b/fs/fs.c
index 78878e7112..933b6bacf3 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -890,6 +890,21 @@ static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
 	return 0;
 }
 
+int unreaddir(DIR *dir, const struct dirent *d)
+{
+	struct readdir_entry *entry;
+
+	if (d != &dir->d)
+		return -EINVAL;
+
+	entry = xzalloc(sizeof(*entry));
+	entry->d = *d;
+	list_add_tail(&entry->list, &dir->entries);
+
+	return 0;
+}
+EXPORT_SYMBOL(unreaddir);
+
 struct dirent *readdir(DIR *dir)
 {
 	struct readdir_entry *entry;