diff options
Diffstat (limited to 'fs/efivarfs/file.c')
-rw-r--r-- | fs/efivarfs/file.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/fs/efivarfs/file.c b/fs/efivarfs/file.c new file mode 100644 index 0000000000..59b52718a3 --- /dev/null +++ b/fs/efivarfs/file.c @@ -0,0 +1,114 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2012 Red Hat, Inc. + * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com> + */ + +#include <linux/efi.h> +#include <linux/delay.h> +#include <linux/fs.h> +#include <linux/slab.h> +#include <linux/mount.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 { + inode_lock(inode); + i_size_write(inode, datasize + sizeof(attributes)); + inode->i_mtime = inode_set_ctime_current(inode); + inode_unlock(inode); + } + + 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; + + while (!__ratelimit(&file->f_cred->user->ratelimit)) + msleep(50); + + 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, +}; |