acl.c

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/*
 *   Copyright (C) International Business Machines  Corp., 2002-2004
 *   Copyright (C) Andreas Gruenbacher, 2001
 *   Copyright (C) Linus Torvalds, 1991, 1992
 *
 *   This program is free software;  you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   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 for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program;  if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/posix_acl_xattr.h>
#include "jfs_incore.h"
#include "jfs_txnmgr.h"
#include "jfs_xattr.h"
#include "jfs_acl.h"

struct posix_acl *jfs_get_acl(struct inode *inode, int type)
{
    struct posix_acl *acl;
    char *ea_name;
    int size;
    char *value = NULL;

    acl = get_cached_acl(inode, type);
    if (acl != ACL_NOT_CACHED)
        return acl;

    switch(type) {
        case ACL_TYPE_ACCESS:
            ea_name = POSIX_ACL_XATTR_ACCESS;
            break;
        case ACL_TYPE_DEFAULT:
            ea_name = POSIX_ACL_XATTR_DEFAULT;
            break;
        default:
            return ERR_PTR(-EINVAL);
    }

    size = __jfs_getxattr(inode, ea_name, NULL, 0);

    if (size > 0) {
        value = kmalloc(size, GFP_KERNEL);
        if (!value)
            return ERR_PTR(-ENOMEM);
        size = __jfs_getxattr(inode, ea_name, value, size);
    }

    if (size < 0) {
        if (size == -ENODATA)
            acl = NULL;
        else
            acl = ERR_PTR(size);
    } else {
        acl = posix_acl_from_xattr(&init_user_ns, value, size);
    }
    kfree(value);
    if (!IS_ERR(acl))
        set_cached_acl(inode, type, acl);
    return acl;
}

static int jfs_set_acl(tid_t tid, struct inode *inode, int type,
               struct posix_acl *acl)
{
    char *ea_name;
    int rc;
    int size = 0;
    char *value = NULL;

    if (S_ISLNK(inode->i_mode))
        return -EOPNOTSUPP;

    switch(type) {
        case ACL_TYPE_ACCESS:
            ea_name = POSIX_ACL_XATTR_ACCESS;
            break;
        case ACL_TYPE_DEFAULT:
            ea_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);
        value = kmalloc(size, GFP_KERNEL);
        if (!value)
            return -ENOMEM;
        rc = posix_acl_to_xattr(&init_user_ns, acl, value, size);
        if (rc < 0)
            goto out;
    }
    rc = __jfs_setxattr(tid, inode, ea_name, value, size, 0);
out:
    kfree(value);

    if (!rc)
        set_cached_acl(inode, type, acl);

    return rc;
}

int jfs_init_acl(tid_t tid, struct inode *inode, struct inode *dir)
{
    struct posix_acl *acl = NULL;
    int rc = 0;

    if (S_ISLNK(inode->i_mode))
        return 0;

    acl = jfs_get_acl(dir, ACL_TYPE_DEFAULT);
    if (IS_ERR(acl))
        return PTR_ERR(acl);

    if (acl) {
        if (S_ISDIR(inode->i_mode)) {
            rc = jfs_set_acl(tid, inode, ACL_TYPE_DEFAULT, acl);
            if (rc)
                goto cleanup;
        }
        rc = posix_acl_create(&acl, GFP_KERNEL, &inode->i_mode);
        if (rc < 0)
            goto cleanup; /* posix_acl_release(NULL) is no-op */
        if (rc > 0)
            rc = jfs_set_acl(tid, inode, ACL_TYPE_ACCESS, acl);
cleanup:
        posix_acl_release(acl);
    } else
        inode->i_mode &= ~current_umask();

    JFS_IP(inode)->mode2 = (JFS_IP(inode)->mode2 & 0xffff0000) |
                   inode->i_mode;

    return rc;
}

int jfs_acl_chmod(struct inode *inode)
{
    struct posix_acl *acl;
    int rc;
    tid_t tid;

    if (S_ISLNK(inode->i_mode))
        return -EOPNOTSUPP;

    acl = jfs_get_acl(inode, ACL_TYPE_ACCESS);
    if (IS_ERR(acl) || !acl)
        return PTR_ERR(acl);

    rc = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
    if (rc)
        return rc;

    tid = txBegin(inode->i_sb, 0);
    mutex_lock(&JFS_IP(inode)->commit_mutex);
    rc = jfs_set_acl(tid, inode, ACL_TYPE_ACCESS, acl);
    if (!rc)
        rc = txCommit(tid, 1, &inode, 0);
    txEnd(tid);
    mutex_unlock(&JFS_IP(inode)->commit_mutex);

    posix_acl_release(acl);
    return rc;
}