hfsplus: implement POSIX ACLs support

Implement POSIX ACLs support in hfsplus driver.
Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/hfsplus/posix_acl.c

+/*
+ * linux/fs/hfsplus/posix_acl.c
+ *
+ * Vyacheslav Dubeyko <slava@dubeyko.com>
+ *
+ * Handler for Posix Access Control Lists (ACLs) support.
+ */
+
+#include "hfsplus_fs.h"
+#include "xattr.h"
+#include "acl.h"
+
+struct posix_acl *hfsplus_get_posix_acl(struct inode *inode, int type)
+{
+	struct posix_acl *acl;
+	char *xattr_name;
+	char *value = NULL;
+	ssize_t size;
+
+	acl = get_cached_acl(inode, type);
+	if (acl != ACL_NOT_CACHED)
+		return acl;
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		xattr_name = POSIX_ACL_XATTR_ACCESS;
+		break;
+	case ACL_TYPE_DEFAULT:
+		xattr_name = POSIX_ACL_XATTR_DEFAULT;
+		break;
+	default:
+		return ERR_PTR(-EINVAL);
+	}
+
+	size = __hfsplus_getxattr(inode, xattr_name, NULL, 0);
+
+	if (size > 0) {
+		value = (char *)hfsplus_alloc_attr_entry();
+		if (unlikely(!value))
+			return ERR_PTR(-ENOMEM);
+		size = __hfsplus_getxattr(inode, xattr_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);
+
+	hfsplus_destroy_attr_entry((hfsplus_attr_entry *)value);
+
+	if (!IS_ERR(acl))
+		set_cached_acl(inode, type, acl);
+
+	return acl;
+}
+
+static int hfsplus_set_posix_acl(struct inode *inode,
+					int type,
+					struct posix_acl *acl)
+{
+	int err;
+	char *xattr_name;
+	size_t size = 0;
+	char *value = NULL;
+
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		xattr_name = POSIX_ACL_XATTR_ACCESS;
+		if (acl) {
+			err = posix_acl_equiv_mode(acl, &inode->i_mode);
+			if (err < 0)
+				return err;
+		}
+		err = 0;
+		break;
+
+	case ACL_TYPE_DEFAULT:
+		xattr_name = POSIX_ACL_XATTR_DEFAULT;
+		if (!S_ISDIR(inode->i_mode))
+			return acl ? -EACCES : 0;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	if (acl) {
+		size = posix_acl_xattr_size(acl->a_count);
+		if (unlikely(size > HFSPLUS_MAX_INLINE_DATA_SIZE))
+			return -ENOMEM;
+		value = (char *)hfsplus_alloc_attr_entry();
+		if (unlikely(!value))
+			return -ENOMEM;
+		err = posix_acl_to_xattr(&init_user_ns, acl, value, size);
+		if (unlikely(err < 0))
+			goto end_set_acl;
+	}
+
+	err = __hfsplus_setxattr(inode, xattr_name, value, size, 0);
+
+end_set_acl:
+	hfsplus_destroy_attr_entry((hfsplus_attr_entry *)value);
+
+	if (!err)
+		set_cached_acl(inode, type, acl);
+
+	return err;
+}
+
+int hfsplus_init_posix_acl(struct inode *inode, struct inode *dir)
+{
+	int err = 0;
+	struct posix_acl *acl = NULL;
+
+	hfs_dbg(ACL_MOD,
+		"[%s]: ino %lu, dir->ino %lu\n",
+		__func__, inode->i_ino, dir->i_ino);
+
+	if (S_ISLNK(inode->i_mode))
+		return 0;
+
+	acl = hfsplus_get_posix_acl(dir, ACL_TYPE_DEFAULT);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+
+	if (acl) {
+		if (S_ISDIR(inode->i_mode)) {
+			err = hfsplus_set_posix_acl(inode,
+							ACL_TYPE_DEFAULT,
+							acl);
+			if (unlikely(err))
+				goto init_acl_cleanup;
+		}
+
+		err = posix_acl_create(&acl, GFP_NOFS, &inode->i_mode);
+		if (unlikely(err < 0))
+			return err;
+
+		if (err > 0)
+			err = hfsplus_set_posix_acl(inode,
+							ACL_TYPE_ACCESS,
+							acl);
+	} else
+		inode->i_mode &= ~current_umask();
+
+init_acl_cleanup:
+	posix_acl_release(acl);
+	return err;
+}
+
+int hfsplus_posix_acl_chmod(struct inode *inode)
+{
+	int err;
+	struct posix_acl *acl;
+
+	hfs_dbg(ACL_MOD, "[%s]: ino %lu\n", __func__, inode->i_ino);
+
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+
+	acl = hfsplus_get_posix_acl(inode, ACL_TYPE_ACCESS);
+	if (IS_ERR(acl) || !acl)
+		return PTR_ERR(acl);
+
+	err = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
+	if (unlikely(err))
+		return err;
+
+	err = hfsplus_set_posix_acl(inode, ACL_TYPE_ACCESS, acl);
+	posix_acl_release(acl);
+	return err;
+}
+
+static int hfsplus_xattr_get_posix_acl(struct dentry *dentry,
+					const char *name,
+					void *buffer,
+					size_t size,
+					int type)
+{
+	int err = 0;
+	struct posix_acl *acl;
+
+	hfs_dbg(ACL_MOD,
+		"[%s]: ino %lu, buffer %p, size %zu, type %#x\n",
+		__func__, dentry->d_inode->i_ino, buffer, size, type);
+
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
+
+	acl = hfsplus_get_posix_acl(dentry->d_inode, type);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+	if (acl == NULL)
+		return -ENODATA;
+
+	err = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
+	posix_acl_release(acl);
+
+	return err;
+}
+
+static int hfsplus_xattr_set_posix_acl(struct dentry *dentry,
+					const char *name,
+					const void *value,
+					size_t size,
+					int flags,
+					int type)
+{
+	int err = 0;
+	struct inode *inode = dentry->d_inode;
+	struct posix_acl *acl = NULL;
+
+	hfs_dbg(ACL_MOD,
+		"[%s]: ino %lu, value %p, size %zu, flags %#x, type %#x\n",
+		__func__, inode->i_ino, value, size, flags, type);
+
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
+
+	if (!inode_owner_or_capable(inode))
+		return -EPERM;
+
+	if (value) {
+		acl = posix_acl_from_xattr(&init_user_ns, value, size);
+		if (IS_ERR(acl))
+			return PTR_ERR(acl);
+		else if (acl) {
+			err = posix_acl_valid(acl);
+			if (err)
+				goto end_xattr_set_acl;
+		}
+	}
+
+	err = hfsplus_set_posix_acl(inode, type, acl);
+
+end_xattr_set_acl:
+	posix_acl_release(acl);
+	return err;
+}
+
+static size_t hfsplus_xattr_list_posix_acl(struct dentry *dentry,
+						char *list,
+						size_t list_size,
+						const char *name,
+						size_t name_len,
+						int type)
+{
+	/*
+	 * This method is not used.
+	 * It is used hfsplus_listxattr() instead of generic_listxattr().
+	 */
+	return -EOPNOTSUPP;
+}
+
+const struct xattr_handler hfsplus_xattr_acl_access_handler = {
+	.prefix	= POSIX_ACL_XATTR_ACCESS,
+	.flags	= ACL_TYPE_ACCESS,
+	.list	= hfsplus_xattr_list_posix_acl,
+	.get	= hfsplus_xattr_get_posix_acl,
+	.set	= hfsplus_xattr_set_posix_acl,
+};
+
+const struct xattr_handler hfsplus_xattr_acl_default_handler = {
+	.prefix	= POSIX_ACL_XATTR_DEFAULT,
+	.flags	= ACL_TYPE_DEFAULT,
+	.list	= hfsplus_xattr_list_posix_acl,
+	.get	= hfsplus_xattr_get_posix_acl,
+	.set	= hfsplus_xattr_set_posix_acl,
+};