This patch introduce a new file `acl.c', which implements:
* initializing ACL for new file according to the directory's default ACL,
* getting ACL which finds the ACL releated xattr and converts it to ACL,
* setting ACL function which converts ACL to xattr and creates/changes/
removes the xattr.
On flash ACL format is based on POSIX ACL structures, and POSIX generic
functions, posix_acl_[to|from]_xattr, are called to do the ACL conversion
between in-memory and on-flash ACL.
The ACL xattr handler is not implemented, because UBIFS does not use it.
Signed-off-by: Sheng Yong <shengyong1@xxxxxxxxxx>
---
fs/ubifs/acl.c | 141 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/ubifs/ubifs.h | 14 ++++++
2 files changed, 155 insertions(+)
create mode 100644 fs/ubifs/acl.c
diff --git a/fs/ubifs/acl.c b/fs/ubifs/acl.c
new file mode 100644
index 0000000..bf37875
--- /dev/null
+++ b/fs/ubifs/acl.c
@@ -0,0 +1,141 @@
+/*
+ * This file is part of UBIFS.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/fs.h>
+#include <linux/xattr.h>
+#include <linux/posix_acl_xattr.h>
+
+#include "ubifs.h"
+
+struct posix_acl *ubifs_get_acl(struct inode *inode, int type)
+{
+ struct posix_acl *acl;
+ char *name, *value = NULL;
+ int size = 0;
+
+ switch (type) {
+ case ACL_TYPE_ACCESS:
+ name = XATTR_NAME_POSIX_ACL_ACCESS;
+ break;
+ case ACL_TYPE_DEFAULT:
+ name = XATTR_NAME_POSIX_ACL_DEFAULT;
+ break;
+ default:
+ BUG();
+ }
+
+ size = ubifs_do_getxattr(inode, name, NULL, 0);
+ if (size > 0) {
+ value = kmalloc(size, GFP_KERNEL);
+ if (!value)
+ return ERR_PTR(-ENOMEM);
+ size = ubifs_do_getxattr(inode, name, value, size);
+ }
+ if (size > 0)
+ acl = posix_acl_from_xattr(&init_user_ns, value, size);
+ else if (size == -ENODATA)
+ acl = NULL;
+ else
+ acl = ERR_PTR(size);
+
+ kfree(value);
+ if (!IS_ERR(acl))
+ set_cached_acl(inode, type, acl);
+
+ return acl;
+}
+
+int ubifs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+{
+ char *name;
+ void *value = NULL;
+ size_t size = 0;
+ int flag = 0, err;
+
+ switch (type) {
+ case ACL_TYPE_ACCESS:
+ name = XATTR_NAME_POSIX_ACL_ACCESS;
+ if (acl) {
+ err = posix_acl_equiv_mode(acl, &inode->i_mode);
+ if (err < 0)
+ return err;
+ if (err == 0)
+ acl = NULL;
+ }
+ break;
+
+ case ACL_TYPE_DEFAULT:
+ name = XATTR_NAME_POSIX_ACL_DEFAULT;
+ if (!S_ISDIR(inode->i_mode))
+ return acl ? -EACCES : 0;
+ break;
+
+ default:
+ BUG();
+ }
+
+ if (acl) {
+ size = posix_acl_xattr_size(acl->a_count);
+ value = kmalloc(size, GFP_NOFS);
+ if (!value)
+ return -ENOMEM;
+
+ err = posix_acl_to_xattr(&init_user_ns, acl, value, size);
+ if (err < 0) {
+ kfree(value);
+ return err;
+ }
+ }
+
+ if (size == 0)
+ flag = XATTR_REPLACE;
+ err = ubifs_do_setxattr(inode, name, value, size, flag);
+
+ kfree(value);
+ if (!err)
+ set_cached_acl(inode, type, acl);
+
+ return err;
+}
+
+/*
+ * Initialize the ACLs of a new inode.
+ */
+int ubifs_init_acl(struct inode *dir, struct inode *inode)
+{
+ struct posix_acl *default_acl, *acl;
+ int err;
+
+ err = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
+ if (err)
+ return err;
+
+ if (default_acl) {
+ mutex_lock(&inode->i_mutex);
+ err = ubifs_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);
+ mutex_unlock(&inode->i_mutex);
+ posix_acl_release(default_acl);
+ }
+
+ if (acl) {
+ if (!err) {
+ mutex_lock(&inode->i_mutex);
+ err = ubifs_set_acl(inode, acl, ACL_TYPE_ACCESS);
+ mutex_unlock(&inode->i_mutex);
+ }
+ posix_acl_release(acl);
+ }
+
+ return err;
+}
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 62aa1a5..b9ddc8d 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -1767,6 +1767,20 @@ int ubifs_removexattr(struct dentry *dentry, const char *name);
int ubifs_init_security(struct inode *dentry, struct inode *inode,
const struct qstr *qstr);
+/* acl.c */
+#ifdef CONFIG_UBIFS_FS_POSIX_ACL
+int ubifs_init_acl(struct inode *dir, struct inode *inode);
+int ubifs_set_acl(struct inode *inode, struct posix_acl *acl, int type);
+struct posix_acl *ubifs_get_acl(struct inode *inode, int type);
+#else
+static inline int ubifs_init_acl(struct inode *inode, struct inode *dir)
+{
+ return 0;
+}
+#define ubifs_get_acl NULL
+#define ubifs_set_acl NULL
+#endif
+
/* super.c */
struct inode *ubifs_iget(struct super_block *sb, unsigned long inum);
--
1.9.1
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