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Commit 2aeccbe9 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Al Viro
Browse files

fs: add generic xattr_acl handlers 



With the ->set_acl inode operation we can implement the Posix ACL
xattr handlers in generic code instead of duplicating them all
over the tree.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 893d46e4

fs/posix_acl.c

+102 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/sched.h>

#include <linux/posix_acl.h>

#include <linux/posix_acl_xattr.h>

#include <linux/xattr.h>

#include <linux/export.h>

#include <linux/user_namespace.h>
@@ -611,3 +612,104 @@ posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl, 
	return real_size;

}

EXPORT_SYMBOL (posix_acl_to_xattr);



static int

posix_acl_xattr_get(struct dentry *dentry, const char *name,

		void *value, size_t size, int type)

{

	struct posix_acl *acl;

	int error;



	if (!IS_POSIXACL(dentry->d_inode))

		return -EOPNOTSUPP;

	if (S_ISLNK(dentry->d_inode->i_mode))

		return -EOPNOTSUPP;



	acl = get_acl(dentry->d_inode, type);

	if (IS_ERR(acl))

		return PTR_ERR(acl);

	if (acl == NULL)

		return -ENODATA;



	error = posix_acl_to_xattr(&init_user_ns, acl, value, size);

	posix_acl_release(acl);



	return error;

}



static int

posix_acl_xattr_set(struct dentry *dentry, const char *name,

		const void *value, size_t size, int flags, int type)

{

	struct inode *inode = dentry->d_inode;

	struct posix_acl *acl = NULL;

	int ret;



	if (!IS_POSIXACL(inode))

		return -EOPNOTSUPP;

	if (!inode->i_op->set_acl)

		return -EOPNOTSUPP;



	if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))

		return value ? -EACCES : 0;

	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);



		if (acl) {

			ret = posix_acl_valid(acl);

			if (ret)

				goto out;

		}

	}



	ret = inode->i_op->set_acl(inode, acl, type);

out:

	posix_acl_release(acl);

	return ret;

}



static size_t

posix_acl_xattr_list(struct dentry *dentry, char *list, size_t list_size,

		const char *name, size_t name_len, int type)

{

	const char *xname;

	size_t size;



	if (!IS_POSIXACL(dentry->d_inode))

		return -EOPNOTSUPP;

	if (S_ISLNK(dentry->d_inode->i_mode))

		return -EOPNOTSUPP;



	if (type == ACL_TYPE_ACCESS)

		xname = POSIX_ACL_XATTR_ACCESS;

	else

		xname = POSIX_ACL_XATTR_DEFAULT;



	size = strlen(xname) + 1;

	if (list && size <= list_size)

		memcpy(list, xname, size);

	return size;

}



const struct xattr_handler posix_acl_access_xattr_handler = {

	.prefix = POSIX_ACL_XATTR_ACCESS,

	.flags = ACL_TYPE_ACCESS,

	.list = posix_acl_xattr_list,

	.get = posix_acl_xattr_get,

	.set = posix_acl_xattr_set,

};

EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler);



const struct xattr_handler posix_acl_default_xattr_handler = {

	.prefix = POSIX_ACL_XATTR_DEFAULT,

	.flags = ACL_TYPE_DEFAULT,

	.list = posix_acl_xattr_list,

	.get = posix_acl_xattr_get,

	.set = posix_acl_xattr_set,

};

EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler);

include/linux/posix_acl_xattr.h

+3 −0
Original line number Diff line number Diff line
@@ -69,4 +69,7 @@ struct posix_acl *posix_acl_from_xattr(struct user_namespace *user_ns, 
int posix_acl_to_xattr(struct user_namespace *user_ns,

		       const struct posix_acl *acl, void *buffer, size_t size);



extern const struct xattr_handler posix_acl_access_xattr_handler;

extern const struct xattr_handler posix_acl_default_xattr_handler;



#endif	/* _POSIX_ACL_XATTR_H */