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>

diff --git a/fs/fs.c b/fs/fs.c
index 9c2ef6b6597ca30de8b49aeb9d5e0c1e1663d907..8fe2403a46aea48e122972d9e4bdf65ba645148b 100644 (file)
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -41,6 +41,11 @@ static inline int fs_ls_unsupported(const char *dirname)
        return -1;
 }
 
+static inline int fs_exists_unsupported(const char *filename)
+{
+       return 0;
+}
+
 static inline int fs_read_unsupported(const char *filename, void *buf,
                                      int offset, int len)
 {
@@ -62,6 +67,7 @@ struct fstype_info {
        int (*probe)(block_dev_desc_t *fs_dev_desc,
                     disk_partition_t *fs_partition);
        int (*ls)(const char *dirname);
+       int (*exists)(const char *filename);
        int (*read)(const char *filename, void *buf, int offset, int len);
        int (*write)(const char *filename, void *buf, int offset, int len);
        void (*close)(void);
@@ -74,6 +80,7 @@ static struct fstype_info fstypes[] = {
                .probe = fat_set_blk_dev,
                .close = fat_close,
                .ls = file_fat_ls,
+               .exists = fs_exists_unsupported,
                .read = fat_read_file,
                .write = fs_write_unsupported,
        },
@@ -84,6 +91,7 @@ static struct fstype_info fstypes[] = {
                .probe = ext4fs_probe,
                .close = ext4fs_close,
                .ls = ext4fs_ls,
+               .exists = fs_exists_unsupported,
                .read = ext4_read_file,
                .write = fs_write_unsupported,
        },
@@ -94,6 +102,7 @@ static struct fstype_info fstypes[] = {
                .probe = sandbox_fs_set_blk_dev,
                .close = sandbox_fs_close,
                .ls = sandbox_fs_ls,
+               .exists = fs_exists_unsupported,
                .read = fs_read_sandbox,
                .write = fs_write_sandbox,
        },
@@ -103,6 +112,7 @@ static struct fstype_info fstypes[] = {
                .probe = fs_probe_unsupported,
                .close = fs_close_unsupported,
                .ls = fs_ls_unsupported,
+               .exists = fs_exists_unsupported,
                .read = fs_read_unsupported,
                .write = fs_write_unsupported,
        },
@@ -184,6 +194,19 @@ int fs_ls(const char *dirname)
        return ret;
 }
 
+int fs_exists(const char *filename)
+{
+       int ret;
+
+       struct fstype_info *info = fs_get_info(fs_type);
+
+       ret = info->exists(filename);
+
+       fs_close();
+
+       return ret;
+}
+
 int fs_read(const char *filename, ulong addr, int offset, int len)
 {
        struct fstype_info *info = fs_get_info(fs_type);
@@ -309,6 +332,15 @@ int do_ls(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
        return 0;
 }
 
+int file_exists(const char *dev_type, const char *dev_part, const char *file,
+               int fstype)
+{
+       if (fs_set_blk_dev(dev_type, dev_part, fstype))
+               return 0;
+
+       return fs_exists(file);
+}
+
 int do_save(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
                int fstype)
 {

diff --git a/include/fs.h b/include/fs.h
index 97b0094e954b92ba0fde6606d8c534f9bcd52f55..26de0539f7d9d9f47e4250b46af92417dd5c9d26 100644 (file)
--- a/include/fs.h
+++ b/include/fs.h
@@ -43,6 +43,13 @@ 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"
@@ -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);