Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / fs / efivarfs / file.c

diff --git a/kernel/fs/efivarfs/file.c b/kernel/fs/efivarfs/file.c
new file mode 100644 (file)
index 0000000..90001da
--- /dev/null
+++ b/kernel/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 <linux/slab.h>
+
+#include "internal.h"
+
+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;
+       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 = memdup_user(userbuf + sizeof(attributes), datasize);
+       if (IS_ERR(data))
+               return PTR_ERR(data);
+
+       bytes = efivar_entry_set_get_size(var, attributes, &datasize,
+                                         data, &set);
+       if (!set && bytes) {
+               if (bytes == -ENOENT)
+                       bytes = -EIO;
+               goto out;
+       }
+
+       if (bytes == -ENOENT) {
+               drop_nlink(inode);
+               d_delete(file->f_path.dentry);
+               dput(file->f_path.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);
+
+       /*
+        * efivarfs represents uncommitted variables with
+        * zero-length files. Reading them should return EOF.
+        */
+       if (err == -ENOENT)
+               return 0;
+       else 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   = simple_open,
+       .read   = efivarfs_file_read,
+       .write  = efivarfs_file_write,
+       .llseek = no_llseek,
+};