fs: implement infrastructure for an 'exists' function

This could be used in scripts such as:

if test -e mmc 0:1 /boot/boot.scr; then
    load mmc 0:1 ${scriptaddr} /boot/boot.scr
    source ${scriptaddr}
fi

rather than:

if load mmc 0:1 ${scriptaddr} /boot/boot.scr; then
    source ${scriptaddr}
fi

This prevents errors being printed by attempts to load non-existent
files, which can be important when checking for a large set of files,
such as /boot/boot.scr.uimg, /boot/boot.scr, /boot/extlinux.conf,
/boot.scr.uimg, /boot.scr, /extlinux.conf.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/fs.h b/include/fs.h
index 97b0094..26de053 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -44,6 +44,13 @@ int fs_set_blk_dev(const char *ifname, const char *dev_part_str, int fstype);
 int fs_ls(const char *dirname);
 
 /*
+ * Determine whether a file exists
+ *
+ * Returns 1 if the file exists, 0 if it doesn't exist.
+ */
+int fs_exists(const char *filename);
+
+/*
  * Read file "filename" from the partition previously set by fs_set_blk_dev(),
  * to address "addr", starting at byte offset "offset", and reading "len"
  * bytes. "offset" may be 0 to read from the start of the file. "len" may be
@@ -72,6 +79,8 @@ int do_load(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
 		int fstype);
 int do_ls(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
 		int fstype);
+int file_exists(const char *dev_type, const char *dev_part, const char *file,
+		int fstype);
 int do_save(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
 		int fstype);