path: root/fs/debugfs/file.c
diff options
authorMichael Ellerman <michael@ellerman.id.au>2006-03-07 21:41:59 +1100
committerGreg Kroah-Hartman <gregkh@suse.de>2006-03-20 13:42:59 -0800
commitdd308bc355a1aa4f202fe9a3133b6c676cb9606c (patch)
treeaccab2f0576da81d5e0ccfdbcc07f25a2a232008 /fs/debugfs/file.c
parentc516865cfbac0d862d4888df91793ad1e74ffd58 (diff)
[PATCH] debugfs: Add debugfs_create_blob() helper for exporting binary data
I wanted to export a binary blob via debugfs, and although it was pretty easy it seems like it'd be easier if there was a helper for it. It's a pity we need the wrapper struct but I can't see a cleaner way to do it. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs/debugfs/file.c')
1 files changed, 46 insertions, 0 deletions
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index d575452cd9f..40c4fc973fa 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -251,3 +251,49 @@ struct dentry *debugfs_create_bool(const char *name, mode_t mode,
+static ssize_t read_file_blob(struct file *file, char __user *user_buf,
+ size_t count, loff_t *ppos)
+ struct debugfs_blob_wrapper *blob = file->private_data;
+ return simple_read_from_buffer(user_buf, count, ppos, blob->data,
+ blob->size);
+static struct file_operations fops_blob = {
+ .read = read_file_blob,
+ .open = default_open,
+ * debugfs_create_blob - create a file in the debugfs filesystem that is
+ * used to read and write a binary blob.
+ *
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file. This should be a
+ * directory dentry if set. If this paramater is NULL, then the
+ * file will be created in the root of the debugfs filesystem.
+ * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
+ * to the blob data and the size of the data.
+ *
+ * This function creates a file in debugfs with the given name that exports
+ * @blob->data as a binary blob. If the @mode variable is so set it can be
+ * read from. Writing is not supported.
+ *
+ * This function will return a pointer to a dentry if it succeeds. This
+ * pointer must be passed to the debugfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here.) If an error occurs, NULL will be returned.
+ *
+ * If debugfs is not enabled in the kernel, the value -ENODEV will be
+ * returned. It is not wise to check for this value, but rather, check for
+ * NULL or !NULL instead as to eliminate the need for #ifdef in the calling
+ * code.
+ */
+struct dentry *debugfs_create_blob(const char *name, mode_t mode,
+ struct dentry *parent,
+ struct debugfs_blob_wrapper *blob)
+ return debugfs_create_file(name, mode, parent, blob, &fops_blob);