--- /dev/null
+/*
+ * 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/ctype.h>
+#include <linux/efi.h>
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/pagemap.h>
+#include <linux/ucs2_string.h>
+#include <linux/slab.h>
+#include <linux/magic.h>
+
+#include "internal.h"
+
+LIST_HEAD(efivarfs_list);
+
+static void efivarfs_evict_inode(struct inode *inode)
+{
+ clear_inode(inode);
+}
+
+static const struct super_operations efivarfs_ops = {
+ .statfs = simple_statfs,
+ .drop_inode = generic_delete_inode,
+ .evict_inode = efivarfs_evict_inode,
+ .show_options = generic_show_options,
+};
+
+static struct super_block *efivarfs_sb;
+
+/*
+ * Compare two efivarfs file names.
+ *
+ * An efivarfs filename is composed of two parts,
+ *
+ * 1. A case-sensitive variable name
+ * 2. A case-insensitive GUID
+ *
+ * So we need to perform a case-sensitive match on part 1 and a
+ * case-insensitive match on part 2.
+ */
+static int efivarfs_d_compare(const struct dentry *parent,
+ const struct dentry *dentry,
+ unsigned int len, const char *str,
+ const struct qstr *name)
+{
+ int guid = len - EFI_VARIABLE_GUID_LEN;
+
+ if (name->len != len)
+ return 1;
+
+ /* Case-sensitive compare for the variable name */
+ if (memcmp(str, name->name, guid))
+ return 1;
+
+ /* Case-insensitive compare for the GUID */
+ return strncasecmp(name->name + guid, str + guid, EFI_VARIABLE_GUID_LEN);
+}
+
+static int efivarfs_d_hash(const struct dentry *dentry, struct qstr *qstr)
+{
+ unsigned long hash = init_name_hash();
+ const unsigned char *s = qstr->name;
+ unsigned int len = qstr->len;
+
+ if (!efivarfs_valid_name(s, len))
+ return -EINVAL;
+
+ while (len-- > EFI_VARIABLE_GUID_LEN)
+ hash = partial_name_hash(*s++, hash);
+
+ /* GUID is case-insensitive. */
+ while (len--)
+ hash = partial_name_hash(tolower(*s++), hash);
+
+ qstr->hash = end_name_hash(hash);
+ return 0;
+}
+
+static const struct dentry_operations efivarfs_d_ops = {
+ .d_compare = efivarfs_d_compare,
+ .d_hash = efivarfs_d_hash,
+ .d_delete = always_delete_dentry,
+};
+
+static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
+{
+ struct dentry *d;
+ struct qstr q;
+ int err;
+
+ q.name = name;
+ q.len = strlen(name);
+
+ err = efivarfs_d_hash(NULL, &q);
+ if (err)
+ return ERR_PTR(err);
+
+ d = d_alloc(parent, &q);
+ if (d)
+ return d;
+
+ return ERR_PTR(-ENOMEM);
+}
+
+static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
+ unsigned long name_size, void *data)
+{
+ struct super_block *sb = (struct super_block *)data;
+ struct efivar_entry *entry;
+ struct inode *inode = NULL;
+ struct dentry *dentry, *root = sb->s_root;
+ unsigned long size = 0;
+ char *name;
+ int len, i;
+ int err = -ENOMEM;
+
+ entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+ if (!entry)
+ return err;
+
+ memcpy(entry->var.VariableName, name16, name_size);
+ memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
+
+ len = ucs2_strlen(entry->var.VariableName);
+
+ /* name, plus '-', plus GUID, plus NUL*/
+ name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL);
+ if (!name)
+ goto fail;
+
+ for (i = 0; i < len; i++)
+ name[i] = entry->var.VariableName[i] & 0xFF;
+
+ name[len] = '-';
+
+ efi_guid_to_str(&entry->var.VendorGuid, name + len + 1);
+
+ name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';
+
+ inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0);
+ if (!inode)
+ goto fail_name;
+
+ dentry = efivarfs_alloc_dentry(root, name);
+ if (IS_ERR(dentry)) {
+ err = PTR_ERR(dentry);
+ goto fail_inode;
+ }
+
+ /* copied by the above to local storage in the dentry. */
+ kfree(name);
+
+ efivar_entry_size(entry, &size);
+ efivar_entry_add(entry, &efivarfs_list);
+
+ mutex_lock(&inode->i_mutex);
+ inode->i_private = entry;
+ i_size_write(inode, size + sizeof(entry->var.Attributes));
+ mutex_unlock(&inode->i_mutex);
+ d_add(dentry, inode);
+
+ return 0;
+
+fail_inode:
+ iput(inode);
+fail_name:
+ kfree(name);
+fail:
+ kfree(entry);
+ return err;
+}
+
+static int efivarfs_destroy(struct efivar_entry *entry, void *data)
+{
+ efivar_entry_remove(entry);
+ kfree(entry);
+ return 0;
+}
+
+static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
+{
+ struct inode *inode = NULL;
+ struct dentry *root;
+ int err;
+
+ efivarfs_sb = sb;
+
+ sb->s_maxbytes = MAX_LFS_FILESIZE;
+ sb->s_blocksize = PAGE_CACHE_SIZE;
+ sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+ sb->s_magic = EFIVARFS_MAGIC;
+ sb->s_op = &efivarfs_ops;
+ sb->s_d_op = &efivarfs_d_ops;
+ sb->s_time_gran = 1;
+
+ inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0);
+ if (!inode)
+ return -ENOMEM;
+ inode->i_op = &efivarfs_dir_inode_operations;
+
+ root = d_make_root(inode);
+ sb->s_root = root;
+ if (!root)
+ return -ENOMEM;
+
+ INIT_LIST_HEAD(&efivarfs_list);
+
+ err = efivar_init(efivarfs_callback, (void *)sb, false,
+ true, &efivarfs_list);
+ if (err)
+ __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);
+
+ return err;
+}
+
+static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data)
+{
+ return mount_single(fs_type, flags, data, efivarfs_fill_super);
+}
+
+static void efivarfs_kill_sb(struct super_block *sb)
+{
+ kill_litter_super(sb);
+ efivarfs_sb = NULL;
+
+ /* Remove all entries and destroy */
+ __efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);
+}
+
+static struct file_system_type efivarfs_type = {
+ .owner = THIS_MODULE,
+ .name = "efivarfs",
+ .mount = efivarfs_mount,
+ .kill_sb = efivarfs_kill_sb,
+};
+
+static __init int efivarfs_init(void)
+{
+ if (!efi_enabled(EFI_RUNTIME_SERVICES))
+ return -ENODEV;
+
+ if (!efivars_kobject())
+ return -ENODEV;
+
+ return register_filesystem(&efivarfs_type);
+}
+
+static __exit void efivarfs_exit(void)
+{
+ unregister_filesystem(&efivarfs_type);
+}
+
+MODULE_AUTHOR("Matthew Garrett, Jeremy Kerr");
+MODULE_DESCRIPTION("EFI Variable Filesystem");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_FS("efivarfs");
+
+module_init(efivarfs_init);
+module_exit(efivarfs_exit);
Code Review / kvmfornfv.git / blobdiff