1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2012 Red Hat, Inc.
4 * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com>
8 #include <linux/delay.h>
10 #include <linux/slab.h>
11 #include <linux/mount.h>
15 static ssize_t efivarfs_file_write(struct file *file,
16 const char __user *userbuf, size_t count, loff_t *ppos)
18 struct efivar_entry *var = file->private_data;
21 struct inode *inode = file->f_mapping->host;
22 unsigned long datasize = count - sizeof(attributes);
26 if (count < sizeof(attributes))
29 if (copy_from_user(&attributes, userbuf, sizeof(attributes)))
32 if (attributes & ~(EFI_VARIABLE_MASK))
35 data = memdup_user(userbuf + sizeof(attributes), datasize);
39 bytes = efivar_entry_set_get_size(var, attributes, &datasize,
47 if (bytes == -ENOENT) {
49 d_delete(file->f_path.dentry);
50 dput(file->f_path.dentry);
53 i_size_write(inode, datasize + sizeof(attributes));
65 static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
66 size_t count, loff_t *ppos)
68 struct efivar_entry *var = file->private_data;
69 unsigned long datasize = 0;
75 while (!__ratelimit(&file->f_cred->user->ratelimit)) {
76 if (!msleep_interruptible(50))
80 err = efivar_entry_size(var, &datasize);
83 * efivarfs represents uncommitted variables with
84 * zero-length files. Reading them should return EOF.
91 data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);
96 size = efivar_entry_get(var, &attributes, &datasize,
97 data + sizeof(attributes));
101 memcpy(data, &attributes, sizeof(attributes));
102 size = simple_read_from_buffer(userbuf, count, ppos,
103 data, datasize + sizeof(attributes));
111 efivarfs_ioc_getxflags(struct file *file, void __user *arg)
113 struct inode *inode = file->f_mapping->host;
114 unsigned int i_flags;
115 unsigned int flags = 0;
117 i_flags = inode->i_flags;
118 if (i_flags & S_IMMUTABLE)
119 flags |= FS_IMMUTABLE_FL;
121 if (copy_to_user(arg, &flags, sizeof(flags)))
127 efivarfs_ioc_setxflags(struct file *file, void __user *arg)
129 struct inode *inode = file->f_mapping->host;
131 unsigned int i_flags = 0;
134 if (!inode_owner_or_capable(inode))
137 if (copy_from_user(&flags, arg, sizeof(flags)))
140 if (flags & ~FS_IMMUTABLE_FL)
143 if (!capable(CAP_LINUX_IMMUTABLE))
146 if (flags & FS_IMMUTABLE_FL)
147 i_flags |= S_IMMUTABLE;
150 error = mnt_want_write_file(file);
155 inode_set_flags(inode, i_flags, S_IMMUTABLE);
158 mnt_drop_write_file(file);
164 efivarfs_file_ioctl(struct file *file, unsigned int cmd, unsigned long p)
166 void __user *arg = (void __user *)p;
169 case FS_IOC_GETFLAGS:
170 return efivarfs_ioc_getxflags(file, arg);
171 case FS_IOC_SETFLAGS:
172 return efivarfs_ioc_setxflags(file, arg);
178 const struct file_operations efivarfs_file_operations = {
180 .read = efivarfs_file_read,
181 .write = efivarfs_file_write,
183 .unlocked_ioctl = efivarfs_file_ioctl,