efivarfs: Move to fs/efivarfs

Now that efivarfs uses the efivar API, move it out of efivars.c and
into fs/efivarfs where it belongs. This move will eventually allow us
to enable the efivarfs code without having to also enable
CONFIG_EFI_VARS built, and vice versa.

Furthermore, things like,

    mount -t efivarfs none /sys/firmware/efi/efivars

will now work if efivarfs is built as a module without requiring the
use of MODULE_ALIAS(), which would have been necessary when the
efivarfs code was part of efivars.c.

Cc: Matthew Garrett <matthew.garrett@nebula.com>
Cc: Jeremy Kerr <jk@ozlabs.org>
Reviewed-by: Tom Gundersen <teg@jklm.no>
Tested-by: Tom Gundersen <teg@jklm.no>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

1 files changed, 111 insertions, 0 deletions

diff --git a/fs/efivarfs/file.c b/fs/efivarfs/file.c
new file mode 100644
index 000000000000..aeb0368dace2
--- /dev/null
+++ b/fs/efivarfs/file.c
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/efi.h>
+#include <linux/fs.h>
+
+#include "internal.h"
+
+static int efivarfs_file_open(struct inode *inode, struct file *file)
+{
+        file->private_data = inode->i_private;
+        return 0;
+}
+
+static ssize_t efivarfs_file_write(struct file *file,
+                const char __user *userbuf, size_t count, loff_t *ppos)
+{
+        struct efivar_entry *var = file->private_data;
+        void *data;
+        u32 attributes;
+        struct inode *inode = file->f_mapping->host;
+        unsigned long datasize = count - sizeof(attributes);
+        ssize_t bytes = 0;
+        bool set = false;
+
+        if (count < sizeof(attributes))
+                return -EINVAL;
+
+        if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
+                return -EFAULT;
+
+        if (attributes & ~(EFI_VARIABLE_MASK))
+                return -EINVAL;
+
+        data = kmalloc(datasize, GFP_KERNEL);
+        if (!data)
+                return -ENOMEM;
+
+        if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) {
+                bytes = -EFAULT;
+                goto out;
+        }
+
+        bytes = efivar_entry_set_get_size(var, attributes, &datasize,
+                                          data, &set);
+        if (!set && bytes)
+                goto out;
+
+        if (bytes == -ENOENT) {
+                drop_nlink(inode);
+                d_delete(file->f_dentry);
+                dput(file->f_dentry);
+        } else {
+                mutex_lock(&inode->i_mutex);
+                i_size_write(inode, datasize + sizeof(attributes));
+                mutex_unlock(&inode->i_mutex);
+        }
+
+        bytes = count;
+
+out:
+        kfree(data);
+
+        return bytes;
+}
+
+static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
+                size_t count, loff_t *ppos)
+{
+        struct efivar_entry *var = file->private_data;
+        unsigned long datasize = 0;
+        u32 attributes;
+        void *data;
+        ssize_t size = 0;
+        int err;
+
+        err = efivar_entry_size(var, &datasize);
+        if (err)
+                return err;
+
+        data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
+
+        if (!data)
+                return -ENOMEM;
+
+        size = efivar_entry_get(var, &attributes, &datasize,
+                                data + sizeof(attributes));
+        if (size)
+                goto out_free;
+
+        memcpy(data, &attributes, sizeof(attributes));
+        size = simple_read_from_buffer(userbuf, count, ppos,
+                                       data, datasize + sizeof(attributes));
+out_free:
+        kfree(data);
+
+        return size;
+}
+
+const struct file_operations efivarfs_file_operations = {
+        .open   = efivarfs_file_open,
+        .read   = efivarfs_file_read,
+        .write  = efivarfs_file_write,
+        .llseek = no_llseek,
+};