/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
 * vim:expandtab:shiftwidth=8:tabstop=8:
 *
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * 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 version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lustre/mdd/mdd_permission.c
 *
 * Lustre Metadata Server (mdd) routines
 *
 * Author: fangyong@clusterfs.com
 * Author: lsy@clusterfs.com
 */
#ifndef EXPORT_SYMTAB
# define EXPORT_SYMTAB
#endif
#define DEBUG_SUBSYSTEM S_MDS

#include <linux/module.h>
#ifdef HAVE_EXT4_LDISKFS
#include <ldiskfs/ldiskfs_jbd2.h>
#else
#include <linux/jbd.h>
#endif
#include <obd.h>
#include <obd_class.h>
#include <lustre_ver.h>
#include <obd_support.h>
#include <lprocfs_status.h>

#ifdef HAVE_EXT4_LDISKFS
#include <ldiskfs/ldiskfs.h>
#else
#include <linux/ldiskfs_fs.h>
#endif
#include <lustre_mds.h>
#include <lustre/lustre_idl.h>

#include "mdd_internal.h"

#ifdef CONFIG_FS_POSIX_ACL

/*
 * Get default acl EA only.
 * Hold read_lock for mdd_obj.
 */
int mdd_def_acl_get(const struct lu_env *env, struct mdd_object *mdd_obj,
                    struct md_attr *ma)
{
        struct lu_buf *buf;
        int rc;
        ENTRY;

        if (ma->ma_valid & MA_ACL_DEF)
                RETURN(0);

        buf = mdd_buf_get(env, ma->ma_acl, ma->ma_acl_size);
        rc = mdo_xattr_get(env, mdd_obj, buf, XATTR_NAME_ACL_DEFAULT,
                           BYPASS_CAPA);
        if (rc > 0) {
                ma->ma_acl_size = rc;
                ma->ma_valid |= MA_ACL_DEF;
                rc = 0;
        } else if ((rc == -EOPNOTSUPP) || (rc == -ENODATA)) {
                rc = 0;
        }
        RETURN(rc);
}

/*
 * Hold write_lock for o.
 */
int mdd_acl_chmod(const struct lu_env *env, struct mdd_object *o, __u32 mode,
                  struct thandle *handle)
{
        struct lu_buf           *buf;
        posix_acl_xattr_header  *head;
        posix_acl_xattr_entry   *entry;
        int                      entry_count;
        int                      rc;

        ENTRY;

        buf = mdd_buf_get(env, mdd_env_info(env)->mti_xattr_buf,
                          sizeof(mdd_env_info(env)->mti_xattr_buf));

        rc = mdo_xattr_get(env, o, buf, XATTR_NAME_ACL_ACCESS, BYPASS_CAPA);
        if ((rc == -EOPNOTSUPP) || (rc == -ENODATA))
                RETURN(0);
        else if (rc <= 0)
                RETURN(rc);

        buf->lb_len = rc;
        head = (posix_acl_xattr_header *)(buf->lb_buf);
        entry = head->a_entries;
        entry_count = (buf->lb_len - sizeof(head->a_version)) /
                      sizeof(posix_acl_xattr_entry);
        if (entry_count <= 0)
                RETURN(0);

        rc = lustre_posix_acl_chmod_masq(entry, mode, entry_count);
        if (rc)
                RETURN(rc);

        rc = mdo_xattr_set(env, o, buf, XATTR_NAME_ACL_ACCESS,
                           0, handle, BYPASS_CAPA);
        RETURN(rc);
}

/*
 * Hold write_lock for obj.
 */
int __mdd_acl_init(const struct lu_env *env, struct mdd_object *obj,
                   struct lu_buf *buf, __u32 *mode, struct thandle *handle)
{
        posix_acl_xattr_header  *head;
        posix_acl_xattr_entry   *entry;
        int                      entry_count;
        int                      rc;

        ENTRY;

        head = (posix_acl_xattr_header *)(buf->lb_buf);
        entry = head->a_entries;
        entry_count = (buf->lb_len - sizeof(head->a_version)) /
                      sizeof(posix_acl_xattr_entry);
        if (entry_count <= 0)
                RETURN(0);

        if (S_ISDIR(*mode)) {
                rc = mdo_xattr_set(env, obj, buf, XATTR_NAME_ACL_DEFAULT, 0,
                                   handle, BYPASS_CAPA);
                if (rc)
                        RETURN(rc);
        }

        rc = lustre_posix_acl_create_masq(entry, mode, entry_count);
        if (rc <= 0)
                RETURN(rc);

        rc = mdo_xattr_set(env, obj, buf, XATTR_NAME_ACL_ACCESS, 0, handle,
                           BYPASS_CAPA);
        RETURN(rc);
}
#endif

/*
 * Hold read_lock for obj.
 */
static int mdd_check_acl(const struct lu_env *env, struct mdd_object *obj,
                         struct lu_attr *la, int mask)
{
#ifdef CONFIG_FS_POSIX_ACL
        struct md_ucred  *uc  = md_ucred(env);
        posix_acl_xattr_header *head;
        posix_acl_xattr_entry *entry;
        struct lu_buf   *buf;
        int entry_count;
        int rc;
        ENTRY;

        buf = mdd_buf_get(env, mdd_env_info(env)->mti_xattr_buf,
                          sizeof(mdd_env_info(env)->mti_xattr_buf));
        rc = mdo_xattr_get(env, obj, buf, XATTR_NAME_ACL_ACCESS,
                           mdd_object_capa(env, obj));
        if (rc <= 0)
                RETURN(rc ? : -EACCES);

        buf->lb_len = rc;
        head = (posix_acl_xattr_header *)(buf->lb_buf);
        entry = head->a_entries;
        entry_count = (buf->lb_len - sizeof(head->a_version)) /
                      sizeof(posix_acl_xattr_entry);

        rc = lustre_posix_acl_permission(uc, la, mask, entry, entry_count);
        RETURN(rc);
#else
        ENTRY;
        RETURN(-EAGAIN);
#endif
}

int __mdd_permission_internal(const struct lu_env *env, struct mdd_object *obj,
                              struct lu_attr *la, int mask, int role)
{
        struct md_ucred *uc = md_ucred(env);
        __u32 mode;
        int rc;
        ENTRY;

        if (mask == 0)
                RETURN(0);

        /* These means unnecessary for permission check */
        if ((uc == NULL) || (uc->mu_valid == UCRED_INIT))
                RETURN(0);

        /* Invalid user credit */
        if (uc->mu_valid == UCRED_INVALID)
                RETURN(-EACCES);

        /*
         * Nobody gets write access to an immutable file.
         */
        if ((mask & MAY_WRITE) && mdd_is_immutable(obj))
                RETURN(-EACCES);

        if (la == NULL) {
                la = &mdd_env_info(env)->mti_la;
                rc = mdd_la_get(env, obj, la, BYPASS_CAPA);
                if (rc)
                        RETURN(rc);
        }

        mode = la->la_mode;
        if (uc->mu_fsuid == la->la_uid) {
                mode >>= 6;
        } else {
                if (mode & S_IRWXG) {
                        if (role != -1)
                                mdd_read_lock(env, obj, role);
                        rc = mdd_check_acl(env, obj, la, mask);
                        if (role != -1)
                                mdd_read_unlock(env, obj);
                        if (rc == -EACCES)
                                goto check_capabilities;
                        else if ((rc != -EAGAIN) && (rc != -EOPNOTSUPP) &&
                                 (rc != -ENODATA))
                                RETURN(rc);
                }
                if (lustre_in_group_p(uc, la->la_gid))
                        mode >>= 3;
        }

        if (((mode & mask & S_IRWXO) == mask))
                RETURN(0);

check_capabilities:
        if (!(mask & MAY_EXEC) ||
            (la->la_mode & S_IXUGO) || S_ISDIR(la->la_mode))
                if (mdd_capable(uc, CFS_CAP_DAC_OVERRIDE))
                        RETURN(0);

        if ((mask == MAY_READ) ||
            (S_ISDIR(la->la_mode) && !(mask & MAY_WRITE)))
                if (mdd_capable(uc, CFS_CAP_DAC_READ_SEARCH))
                        RETURN(0);

        RETURN(-EACCES);
}

int mdd_permission(const struct lu_env *env,
                   struct md_object *pobj, struct md_object *cobj,
                   struct md_attr *ma, int mask)
{
        struct mdd_object *mdd_pobj, *mdd_cobj;
        struct md_ucred *uc = NULL;
        struct lu_attr *la = NULL;
        int check_create, check_link;
        int check_unlink;
        int check_rename_src, check_rename_tar;
        int check_vtx_part, check_vtx_full;
        int check_rgetfacl;
        int rc = 0;
        ENTRY;

        LASSERT(cobj);
        mdd_cobj = md2mdd_obj(cobj);

        /* For cross_open case, the "mask" is open flags,
         * so convert it to permission mask first.
         * XXX: MDS_OPEN_CROSS must be NOT equal to permission mask MAY_*. */
        if (unlikely(mask & MDS_OPEN_CROSS)) {
                la = &mdd_env_info(env)->mti_la;
                rc = mdd_la_get(env, mdd_cobj, la, BYPASS_CAPA);
                if (rc)
                        RETURN(rc);

                mask = accmode(env, la, mask & ~MDS_OPEN_CROSS);
        }

        check_create = mask & MAY_CREATE;
        check_link = mask & MAY_LINK;
        check_unlink = mask & MAY_UNLINK;
        check_rename_src = mask & MAY_RENAME_SRC;
        check_rename_tar = mask & MAY_RENAME_TAR;
        check_vtx_part = mask & MAY_VTX_PART;
        check_vtx_full = mask & MAY_VTX_FULL;
        check_rgetfacl = mask & MAY_RGETFACL;

        mask &= ~(MAY_CREATE | MAY_LINK |
                MAY_UNLINK |
                MAY_RENAME_SRC | MAY_RENAME_TAR |
                MAY_VTX_PART | MAY_VTX_FULL |
                MAY_RGETFACL);

        rc = mdd_permission_internal_locked(env, mdd_cobj, NULL, mask,
                                            MOR_TGT_CHILD);

        if (!rc && (check_create || check_link))
                rc = mdd_may_create(env, mdd_cobj, NULL, 1, check_link);

        if (!rc && check_unlink) {
                LASSERT(ma);
                rc = mdd_may_unlink(env, mdd_cobj, ma);
        }

        if (!rc && (check_rename_src || check_rename_tar)) {
                LASSERT(pobj);
                LASSERT(ma);
                mdd_pobj = md2mdd_obj(pobj);
                rc = mdd_may_delete(env, mdd_pobj, mdd_cobj, ma, 1,
                                    check_rename_tar);
        }

        if (!rc && (check_vtx_part || check_vtx_full)) {
                uc = md_ucred(env);
                LASSERT(ma);
                if (likely(!la)) {
                        la = &mdd_env_info(env)->mti_la;
                        rc = mdd_la_get(env, mdd_cobj, la, BYPASS_CAPA);
                        if (rc)
                                RETURN(rc);
                }

                if (!(la->la_mode & S_ISVTX) || (la->la_uid == uc->mu_fsuid) ||
                    (check_vtx_full && (ma->ma_attr.la_valid & LA_UID) &&
                    (ma->ma_attr.la_uid == uc->mu_fsuid))) {
                        ma->ma_attr_flags |= MDS_VTX_BYPASS;
                } else {
                        ma->ma_attr_flags &= ~MDS_VTX_BYPASS;
                        if (check_vtx_full)
                                rc = -EPERM;
                }
        }

        if (unlikely(!rc && check_rgetfacl)) {
                if (likely(!uc))
                        uc = md_ucred(env);

                if (likely(!la)) {
                        la = &mdd_env_info(env)->mti_la;
                        rc = mdd_la_get(env, mdd_cobj, la, BYPASS_CAPA);
                        if (rc)
                                RETURN(rc);
                }

                if (la->la_uid != uc->mu_fsuid &&
                    !mdd_capable(uc, CFS_CAP_FOWNER))
                        rc = -EPERM;
        }

        RETURN(rc);
}

int mdd_capa_get(const struct lu_env *env, struct md_object *obj,
                 struct lustre_capa *capa, int renewal)
{
        struct mdd_object *mdd_obj = md2mdd_obj(obj);
        struct obd_capa *oc;
        int rc = 0;
        ENTRY;

        oc = mdo_capa_get(env, mdd_obj, renewal ? capa : NULL,
                          capa->lc_opc);
        if (IS_ERR(oc)) {
                rc = PTR_ERR(oc);
        } else if (likely(oc != NULL)) {
                capa_cpy(capa, oc);
                capa_put(oc);
        }

        RETURN(rc);
}