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root/fs/gfs2/acl.c

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DEFINITIONS

This source file includes following definitions.
  1. gfs2_acl_validate_set
  2. gfs2_acl_validate_remove
  3. acl_get
  4. gfs2_check_acl
  5. munge_mode
  6. gfs2_acl_create
  7. gfs2_acl_chmod

/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#include <linux/gfs2_ondisk.h>
#include <linux/lm_interface.h>

#include "gfs2.h"
#include "incore.h"
#include "acl.h"
#include "eaops.h"
#include "eattr.h"
#include "glock.h"
#include "inode.h"
#include "meta_io.h"
#include "trans.h"
#include "util.h"

#define ACL_ACCESS 1
#define ACL_DEFAULT 0

int gfs2_acl_validate_set(struct gfs2_inode *ip, int access,
                      struct gfs2_ea_request *er,
                      int *remove, mode_t *mode)
{
        struct posix_acl *acl;
        int error;

        error = gfs2_acl_validate_remove(ip, access);
        if (error)
                return error;

        if (!er->er_data)
                return -EINVAL;

        acl = posix_acl_from_xattr(er->er_data, er->er_data_len);
        if (IS_ERR(acl))
                return PTR_ERR(acl);
        if (!acl) {
                *remove = 1;
                return 0;
        }

        error = posix_acl_valid(acl);
        if (error)
                goto out;

        if (access) {
                error = posix_acl_equiv_mode(acl, mode);
                if (!error)
                        *remove = 1;
                else if (error > 0)
                        error = 0;
        }

out:
        posix_acl_release(acl);
        return error;
}

int gfs2_acl_validate_remove(struct gfs2_inode *ip, int access)
{
        if (!GFS2_SB(&ip->i_inode)->sd_args.ar_posix_acl)
                return -EOPNOTSUPP;
        if (!is_owner_or_cap(&ip->i_inode))
                return -EPERM;
        if (S_ISLNK(ip->i_inode.i_mode))
                return -EOPNOTSUPP;
        if (!access && !S_ISDIR(ip->i_inode.i_mode))
                return -EACCES;

        return 0;
}

static int acl_get(struct gfs2_inode *ip, int access, struct posix_acl **acl,
                   struct gfs2_ea_location *el, char **data, unsigned int *len)
{
        struct gfs2_ea_request er;
        struct gfs2_ea_location el_this;
        int error;

        if (!ip->i_di.di_eattr)
                return 0;

        memset(&er, 0, sizeof(struct gfs2_ea_request));
        if (access) {
                er.er_name = GFS2_POSIX_ACL_ACCESS;
                er.er_name_len = GFS2_POSIX_ACL_ACCESS_LEN;
        } else {
                er.er_name = GFS2_POSIX_ACL_DEFAULT;
                er.er_name_len = GFS2_POSIX_ACL_DEFAULT_LEN;
        }
        er.er_type = GFS2_EATYPE_SYS;

        if (!el)
                el = &el_this;

        error = gfs2_ea_find(ip, &er, el);
        if (error)
                return error;
        if (!el->el_ea)
                return 0;
        if (!GFS2_EA_DATA_LEN(el->el_ea))
                goto out;

        er.er_data_len = GFS2_EA_DATA_LEN(el->el_ea);
        er.er_data = kmalloc(er.er_data_len, GFP_NOFS);
        error = -ENOMEM;
        if (!er.er_data)
                goto out;

        error = gfs2_ea_get_copy(ip, el, er.er_data);
        if (error)
                goto out_kfree;

        if (acl) {
                *acl = posix_acl_from_xattr(er.er_data, er.er_data_len);
                if (IS_ERR(*acl))
                        error = PTR_ERR(*acl);
        }

out_kfree:
        if (error || !data)
                kfree(er.er_data);
        else {
                *data = er.er_data;
                *len = er.er_data_len;
        }
out:
        if (error || el == &el_this)
                brelse(el->el_bh);
        return error;
}

/**
 * gfs2_check_acl - Check an ACL to see if we're allowed to do something
 * @inode: the file we want to do something to
 * @mask: what we want to do
 *
 * Returns: errno
 */

int gfs2_check_acl(struct inode *inode, int mask)
{
        struct posix_acl *acl = NULL;
        int error;

        error = acl_get(GFS2_I(inode), ACL_ACCESS, &acl, NULL, NULL, NULL);
        if (error)
                return error;

        if (acl) {
                error = posix_acl_permission(inode, acl, mask);
                posix_acl_release(acl);
                return error;
        }

        return -EAGAIN;
}

static int munge_mode(struct gfs2_inode *ip, mode_t mode)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct buffer_head *dibh;
        int error;

        error = gfs2_trans_begin(sdp, RES_DINODE, 0);
        if (error)
                return error;

        error = gfs2_meta_inode_buffer(ip, &dibh);
        if (!error) {
                gfs2_assert_withdraw(sdp,
                                (ip->i_inode.i_mode & S_IFMT) == (mode & S_IFMT));
                ip->i_inode.i_mode = mode;
                gfs2_trans_add_bh(ip->i_gl, dibh, 1);
                gfs2_dinode_out(ip, dibh->b_data);
                brelse(dibh);
        }

        gfs2_trans_end(sdp);

        return 0;
}

int gfs2_acl_create(struct gfs2_inode *dip, struct gfs2_inode *ip)
{
        struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
        struct posix_acl *acl = NULL, *clone;
        struct gfs2_ea_request er;
        mode_t mode = ip->i_inode.i_mode;
        int error;

        if (!sdp->sd_args.ar_posix_acl)
                return 0;
        if (S_ISLNK(ip->i_inode.i_mode))
                return 0;

        memset(&er, 0, sizeof(struct gfs2_ea_request));
        er.er_type = GFS2_EATYPE_SYS;

        error = acl_get(dip, ACL_DEFAULT, &acl, NULL,
                        &er.er_data, &er.er_data_len);
        if (error)
                return error;
        if (!acl) {
                mode &= ~current->fs->umask;
                if (mode != ip->i_inode.i_mode)
                        error = munge_mode(ip, mode);
                return error;
        }

        clone = posix_acl_clone(acl, GFP_NOFS);
        error = -ENOMEM;
        if (!clone)
                goto out;
        posix_acl_release(acl);
        acl = clone;

        if (S_ISDIR(ip->i_inode.i_mode)) {
                er.er_name = GFS2_POSIX_ACL_DEFAULT;
                er.er_name_len = GFS2_POSIX_ACL_DEFAULT_LEN;
                error = gfs2_system_eaops.eo_set(ip, &er);
                if (error)
                        goto out;
        }

        error = posix_acl_create_masq(acl, &mode);
        if (error < 0)
                goto out;
        if (error > 0) {
                er.er_name = GFS2_POSIX_ACL_ACCESS;
                er.er_name_len = GFS2_POSIX_ACL_ACCESS_LEN;
                posix_acl_to_xattr(acl, er.er_data, er.er_data_len);
                er.er_mode = mode;
                er.er_flags = GFS2_ERF_MODE;
                error = gfs2_system_eaops.eo_set(ip, &er);
                if (error)
                        goto out;
        } else
                munge_mode(ip, mode);

out:
        posix_acl_release(acl);
        kfree(er.er_data);
        return error;
}

int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr)
{
        struct posix_acl *acl = NULL, *clone;
        struct gfs2_ea_location el;
        char *data;
        unsigned int len;
        int error;

        error = acl_get(ip, ACL_ACCESS, &acl, &el, &data, &len);
        if (error)
                return error;
        if (!acl)
                return gfs2_setattr_simple(ip, attr);

        clone = posix_acl_clone(acl, GFP_NOFS);
        error = -ENOMEM;
        if (!clone)
                goto out;
        posix_acl_release(acl);
        acl = clone;

        error = posix_acl_chmod_masq(acl, attr->ia_mode);
        if (!error) {
                posix_acl_to_xattr(acl, data, len);
                error = gfs2_ea_acl_chmod(ip, &el, attr, data);
        }

out:
        posix_acl_release(acl);
        brelse(el.el_bh);
        kfree(data);
        return error;
}


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