428 lines
9.6 KiB
C
428 lines
9.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* Extended attribute handling for AFS. We use xattrs to get and set metadata
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* instead of providing pioctl().
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*
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* Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/xattr.h>
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#include "internal.h"
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static const char afs_xattr_list[] =
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"afs.acl\0"
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"afs.cell\0"
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"afs.fid\0"
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"afs.volume\0"
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"afs.yfs.acl\0"
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"afs.yfs.acl_inherited\0"
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"afs.yfs.acl_num_cleaned\0"
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"afs.yfs.vol_acl";
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/*
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* Retrieve a list of the supported xattrs.
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*/
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ssize_t afs_listxattr(struct dentry *dentry, char *buffer, size_t size)
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{
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if (size == 0)
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return sizeof(afs_xattr_list);
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if (size < sizeof(afs_xattr_list))
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return -ERANGE;
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memcpy(buffer, afs_xattr_list, sizeof(afs_xattr_list));
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return sizeof(afs_xattr_list);
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}
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/*
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* Get a file's ACL.
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*/
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static int afs_xattr_get_acl(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_fs_cursor fc;
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struct afs_status_cb *scb;
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struct afs_vnode *vnode = AFS_FS_I(inode);
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struct afs_acl *acl = NULL;
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struct key *key;
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int ret = -ENOMEM;
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scb = kzalloc(sizeof(struct afs_status_cb), GFP_NOFS);
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if (!scb)
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goto error;
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key = afs_request_key(vnode->volume->cell);
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if (IS_ERR(key)) {
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ret = PTR_ERR(key);
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goto error_scb;
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}
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ret = -ERESTARTSYS;
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if (afs_begin_vnode_operation(&fc, vnode, key, true)) {
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afs_dataversion_t data_version = vnode->status.data_version;
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while (afs_select_fileserver(&fc)) {
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fc.cb_break = afs_calc_vnode_cb_break(vnode);
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acl = afs_fs_fetch_acl(&fc, scb);
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}
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afs_check_for_remote_deletion(&fc, fc.vnode);
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afs_vnode_commit_status(&fc, vnode, fc.cb_break,
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&data_version, scb);
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ret = afs_end_vnode_operation(&fc);
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}
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if (ret == 0) {
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ret = acl->size;
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if (size > 0) {
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if (acl->size <= size)
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memcpy(buffer, acl->data, acl->size);
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else
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ret = -ERANGE;
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}
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kfree(acl);
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}
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key_put(key);
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error_scb:
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kfree(scb);
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error:
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return ret;
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}
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/*
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* Set a file's AFS3 ACL.
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*/
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static int afs_xattr_set_acl(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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const void *buffer, size_t size, int flags)
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{
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struct afs_fs_cursor fc;
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struct afs_status_cb *scb;
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struct afs_vnode *vnode = AFS_FS_I(inode);
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struct afs_acl *acl = NULL;
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struct key *key;
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int ret = -ENOMEM;
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if (flags == XATTR_CREATE)
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return -EINVAL;
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scb = kzalloc(sizeof(struct afs_status_cb), GFP_NOFS);
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if (!scb)
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goto error;
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acl = kmalloc(sizeof(*acl) + size, GFP_KERNEL);
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if (!acl)
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goto error_scb;
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key = afs_request_key(vnode->volume->cell);
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if (IS_ERR(key)) {
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ret = PTR_ERR(key);
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goto error_acl;
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}
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acl->size = size;
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memcpy(acl->data, buffer, size);
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ret = -ERESTARTSYS;
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if (afs_begin_vnode_operation(&fc, vnode, key, true)) {
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afs_dataversion_t data_version = vnode->status.data_version;
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while (afs_select_fileserver(&fc)) {
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fc.cb_break = afs_calc_vnode_cb_break(vnode);
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afs_fs_store_acl(&fc, acl, scb);
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}
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afs_check_for_remote_deletion(&fc, fc.vnode);
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afs_vnode_commit_status(&fc, vnode, fc.cb_break,
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&data_version, scb);
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ret = afs_end_vnode_operation(&fc);
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}
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key_put(key);
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error_acl:
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kfree(acl);
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error_scb:
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kfree(scb);
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error:
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return ret;
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}
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static const struct xattr_handler afs_xattr_afs_acl_handler = {
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.name = "afs.acl",
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.get = afs_xattr_get_acl,
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.set = afs_xattr_set_acl,
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};
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/*
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* Get a file's YFS ACL.
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*/
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static int afs_xattr_get_yfs(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_fs_cursor fc;
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struct afs_status_cb *scb;
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struct afs_vnode *vnode = AFS_FS_I(inode);
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struct yfs_acl *yacl = NULL;
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struct key *key;
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char buf[16], *data;
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int which = 0, dsize, ret = -ENOMEM;
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if (strcmp(name, "acl") == 0)
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which = 0;
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else if (strcmp(name, "acl_inherited") == 0)
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which = 1;
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else if (strcmp(name, "acl_num_cleaned") == 0)
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which = 2;
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else if (strcmp(name, "vol_acl") == 0)
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which = 3;
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else
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return -EOPNOTSUPP;
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yacl = kzalloc(sizeof(struct yfs_acl), GFP_KERNEL);
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if (!yacl)
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goto error;
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if (which == 0)
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yacl->flags |= YFS_ACL_WANT_ACL;
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else if (which == 3)
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yacl->flags |= YFS_ACL_WANT_VOL_ACL;
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scb = kzalloc(sizeof(struct afs_status_cb), GFP_NOFS);
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if (!scb)
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goto error_yacl;
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key = afs_request_key(vnode->volume->cell);
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if (IS_ERR(key)) {
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ret = PTR_ERR(key);
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goto error_scb;
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}
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ret = -ERESTARTSYS;
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if (afs_begin_vnode_operation(&fc, vnode, key, true)) {
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afs_dataversion_t data_version = vnode->status.data_version;
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while (afs_select_fileserver(&fc)) {
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fc.cb_break = afs_calc_vnode_cb_break(vnode);
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yfs_fs_fetch_opaque_acl(&fc, yacl, scb);
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}
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afs_check_for_remote_deletion(&fc, fc.vnode);
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afs_vnode_commit_status(&fc, vnode, fc.cb_break,
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&data_version, scb);
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ret = afs_end_vnode_operation(&fc);
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}
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if (ret < 0)
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goto error_key;
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switch (which) {
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case 0:
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data = yacl->acl->data;
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dsize = yacl->acl->size;
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break;
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case 1:
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data = buf;
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dsize = snprintf(buf, sizeof(buf), "%u", yacl->inherit_flag);
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break;
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case 2:
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data = buf;
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dsize = snprintf(buf, sizeof(buf), "%u", yacl->num_cleaned);
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break;
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case 3:
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data = yacl->vol_acl->data;
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dsize = yacl->vol_acl->size;
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break;
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default:
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ret = -EOPNOTSUPP;
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goto error_key;
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}
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ret = dsize;
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if (size > 0) {
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if (dsize > size) {
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ret = -ERANGE;
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goto error_key;
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}
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memcpy(buffer, data, dsize);
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}
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error_key:
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key_put(key);
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error_scb:
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kfree(scb);
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error_yacl:
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yfs_free_opaque_acl(yacl);
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error:
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return ret;
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}
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/*
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* Set a file's YFS ACL.
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*/
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static int afs_xattr_set_yfs(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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const void *buffer, size_t size, int flags)
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{
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struct afs_fs_cursor fc;
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struct afs_status_cb *scb;
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struct afs_vnode *vnode = AFS_FS_I(inode);
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struct afs_acl *acl = NULL;
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struct key *key;
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int ret = -ENOMEM;
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if (flags == XATTR_CREATE ||
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strcmp(name, "acl") != 0)
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return -EINVAL;
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scb = kzalloc(sizeof(struct afs_status_cb), GFP_NOFS);
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if (!scb)
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goto error;
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acl = kmalloc(sizeof(*acl) + size, GFP_KERNEL);
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if (!acl)
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goto error_scb;
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acl->size = size;
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memcpy(acl->data, buffer, size);
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key = afs_request_key(vnode->volume->cell);
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if (IS_ERR(key)) {
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ret = PTR_ERR(key);
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goto error_acl;
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}
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ret = -ERESTARTSYS;
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if (afs_begin_vnode_operation(&fc, vnode, key, true)) {
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afs_dataversion_t data_version = vnode->status.data_version;
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while (afs_select_fileserver(&fc)) {
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fc.cb_break = afs_calc_vnode_cb_break(vnode);
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yfs_fs_store_opaque_acl2(&fc, acl, scb);
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}
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afs_check_for_remote_deletion(&fc, fc.vnode);
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afs_vnode_commit_status(&fc, vnode, fc.cb_break,
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&data_version, scb);
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ret = afs_end_vnode_operation(&fc);
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}
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error_acl:
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kfree(acl);
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key_put(key);
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error_scb:
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kfree(scb);
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error:
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return ret;
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}
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static const struct xattr_handler afs_xattr_yfs_handler = {
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.prefix = "afs.yfs.",
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.get = afs_xattr_get_yfs,
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.set = afs_xattr_set_yfs,
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};
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/*
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* Get the name of the cell on which a file resides.
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*/
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static int afs_xattr_get_cell(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_vnode *vnode = AFS_FS_I(inode);
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struct afs_cell *cell = vnode->volume->cell;
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size_t namelen;
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namelen = cell->name_len;
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if (size == 0)
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return namelen;
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if (namelen > size)
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return -ERANGE;
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memcpy(buffer, cell->name, namelen);
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return namelen;
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}
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static const struct xattr_handler afs_xattr_afs_cell_handler = {
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.name = "afs.cell",
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.get = afs_xattr_get_cell,
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};
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/*
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* Get the volume ID, vnode ID and vnode uniquifier of a file as a sequence of
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* hex numbers separated by colons.
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*/
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static int afs_xattr_get_fid(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_vnode *vnode = AFS_FS_I(inode);
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char text[16 + 1 + 24 + 1 + 8 + 1];
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size_t len;
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/* The volume ID is 64-bit, the vnode ID is 96-bit and the
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* uniquifier is 32-bit.
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*/
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len = sprintf(text, "%llx:", vnode->fid.vid);
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if (vnode->fid.vnode_hi)
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len += sprintf(text + len, "%x%016llx",
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vnode->fid.vnode_hi, vnode->fid.vnode);
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else
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len += sprintf(text + len, "%llx", vnode->fid.vnode);
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len += sprintf(text + len, ":%x", vnode->fid.unique);
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if (size == 0)
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return len;
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if (len > size)
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return -ERANGE;
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memcpy(buffer, text, len);
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return len;
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}
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static const struct xattr_handler afs_xattr_afs_fid_handler = {
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.name = "afs.fid",
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.get = afs_xattr_get_fid,
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};
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/*
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* Get the name of the volume on which a file resides.
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*/
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static int afs_xattr_get_volume(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_vnode *vnode = AFS_FS_I(inode);
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const char *volname = vnode->volume->name;
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size_t namelen;
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namelen = strlen(volname);
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if (size == 0)
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return namelen;
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if (namelen > size)
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return -ERANGE;
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memcpy(buffer, volname, namelen);
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return namelen;
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}
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static const struct xattr_handler afs_xattr_afs_volume_handler = {
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.name = "afs.volume",
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.get = afs_xattr_get_volume,
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};
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const struct xattr_handler *afs_xattr_handlers[] = {
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&afs_xattr_afs_acl_handler,
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&afs_xattr_afs_cell_handler,
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&afs_xattr_afs_fid_handler,
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&afs_xattr_afs_volume_handler,
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&afs_xattr_yfs_handler, /* afs.yfs. prefix */
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NULL
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};
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