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d68772b7 MF |
1 | /* |
2 | * Copyright (C) 2012 Red Hat, Inc. | |
3 | * Copyright (C) 2012 Jeremy Kerr <jeremy.kerr@canonical.com> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2 as | |
7 | * published by the Free Software Foundation. | |
8 | */ | |
9 | ||
10 | #include <linux/efi.h> | |
11 | #include <linux/fs.h> | |
12 | ||
13 | #include "internal.h" | |
14 | ||
15 | static int efivarfs_file_open(struct inode *inode, struct file *file) | |
16 | { | |
17 | file->private_data = inode->i_private; | |
18 | return 0; | |
19 | } | |
20 | ||
21 | static ssize_t efivarfs_file_write(struct file *file, | |
22 | const char __user *userbuf, size_t count, loff_t *ppos) | |
23 | { | |
24 | struct efivar_entry *var = file->private_data; | |
25 | void *data; | |
26 | u32 attributes; | |
27 | struct inode *inode = file->f_mapping->host; | |
28 | unsigned long datasize = count - sizeof(attributes); | |
29 | ssize_t bytes = 0; | |
30 | bool set = false; | |
31 | ||
32 | if (count < sizeof(attributes)) | |
33 | return -EINVAL; | |
34 | ||
35 | if (copy_from_user(&attributes, userbuf, sizeof(attributes))) | |
36 | return -EFAULT; | |
37 | ||
38 | if (attributes & ~(EFI_VARIABLE_MASK)) | |
39 | return -EINVAL; | |
40 | ||
41 | data = kmalloc(datasize, GFP_KERNEL); | |
42 | if (!data) | |
43 | return -ENOMEM; | |
44 | ||
45 | if (copy_from_user(data, userbuf + sizeof(attributes), datasize)) { | |
46 | bytes = -EFAULT; | |
47 | goto out; | |
48 | } | |
49 | ||
50 | bytes = efivar_entry_set_get_size(var, attributes, &datasize, | |
51 | data, &set); | |
52 | if (!set && bytes) | |
53 | goto out; | |
54 | ||
55 | if (bytes == -ENOENT) { | |
56 | drop_nlink(inode); | |
57 | d_delete(file->f_dentry); | |
58 | dput(file->f_dentry); | |
59 | } else { | |
60 | mutex_lock(&inode->i_mutex); | |
61 | i_size_write(inode, datasize + sizeof(attributes)); | |
62 | mutex_unlock(&inode->i_mutex); | |
63 | } | |
64 | ||
65 | bytes = count; | |
66 | ||
67 | out: | |
68 | kfree(data); | |
69 | ||
70 | return bytes; | |
71 | } | |
72 | ||
73 | static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf, | |
74 | size_t count, loff_t *ppos) | |
75 | { | |
76 | struct efivar_entry *var = file->private_data; | |
77 | unsigned long datasize = 0; | |
78 | u32 attributes; | |
79 | void *data; | |
80 | ssize_t size = 0; | |
81 | int err; | |
82 | ||
83 | err = efivar_entry_size(var, &datasize); | |
84 | if (err) | |
85 | return err; | |
86 | ||
87 | data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL); | |
88 | ||
89 | if (!data) | |
90 | return -ENOMEM; | |
91 | ||
92 | size = efivar_entry_get(var, &attributes, &datasize, | |
93 | data + sizeof(attributes)); | |
94 | if (size) | |
95 | goto out_free; | |
96 | ||
97 | memcpy(data, &attributes, sizeof(attributes)); | |
98 | size = simple_read_from_buffer(userbuf, count, ppos, | |
99 | data, datasize + sizeof(attributes)); | |
100 | out_free: | |
101 | kfree(data); | |
102 | ||
103 | return size; | |
104 | } | |
105 | ||
106 | const struct file_operations efivarfs_file_operations = { | |
107 | .open = efivarfs_file_open, | |
108 | .read = efivarfs_file_read, | |
109 | .write = efivarfs_file_write, | |
110 | .llseek = no_llseek, | |
111 | }; |