acl.c

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/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * acl.c
 *
 * Copyright (C) 2004, 2008 Oracle.  All rights reserved.
 *
 * CREDITS:
 * Lots of code in this file is copy from linux/fs/ext3/acl.c.
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License version 2 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 for more details.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>

#include <cluster/masklog.h>

#include "ocfs2.h"
#include "alloc.h"
#include "dlmglue.h"
#include "file.h"
#include "inode.h"
#include "journal.h"
#include "ocfs2_fs.h"

#include "xattr.h"
#include "acl.h"

/*
 * Convert from xattr value to acl struct.
 */
static struct posix_acl *ocfs2_acl_from_xattr(const void *value, size_t size)
{
    int n, count;
    struct posix_acl *acl;

    if (!value)
        return NULL;
    if (size < sizeof(struct posix_acl_entry))
        return ERR_PTR(-EINVAL);

    count = size / sizeof(struct posix_acl_entry);
    if (count < 0)
        return ERR_PTR(-EINVAL);
    if (count == 0)
        return NULL;

    acl = posix_acl_alloc(count, GFP_NOFS);
    if (!acl)
        return ERR_PTR(-ENOMEM);
    for (n = 0; n < count; n++) {
        struct ocfs2_acl_entry *entry =
            (struct ocfs2_acl_entry *)value;

        acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
        acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
        acl->a_entries[n].e_id   = le32_to_cpu(entry->e_id);
        value += sizeof(struct posix_acl_entry);

    }
    return acl;
}

/*
 * Convert acl struct to xattr value.
 */
static void *ocfs2_acl_to_xattr(const struct posix_acl *acl, size_t *size)
{
    struct ocfs2_acl_entry *entry = NULL;
    char *ocfs2_acl;
    size_t n;

    *size = acl->a_count * sizeof(struct posix_acl_entry);

    ocfs2_acl = kmalloc(*size, GFP_NOFS);
    if (!ocfs2_acl)
        return ERR_PTR(-ENOMEM);

    entry = (struct ocfs2_acl_entry *)ocfs2_acl;
    for (n = 0; n < acl->a_count; n++, entry++) {
        entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
        entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
        entry->e_id   = cpu_to_le32(acl->a_entries[n].e_id);
    }
    return ocfs2_acl;
}

static struct posix_acl *ocfs2_get_acl_nolock(struct inode *inode,
                          int type,
                          struct buffer_head *di_bh)
{
    int name_index;
    char *value = NULL;
    struct posix_acl *acl;
    int retval;

    switch (type) {
    case ACL_TYPE_ACCESS:
        name_index = OCFS2_XATTR_INDEX_POSIX_ACL_ACCESS;
        break;
    case ACL_TYPE_DEFAULT:
        name_index = OCFS2_XATTR_INDEX_POSIX_ACL_DEFAULT;
        break;
    default:
        return ERR_PTR(-EINVAL);
    }

    retval = ocfs2_xattr_get_nolock(inode, di_bh, name_index, "", NULL, 0);
    if (retval > 0) {
        value = kmalloc(retval, GFP_NOFS);
        if (!value)
            return ERR_PTR(-ENOMEM);
        retval = ocfs2_xattr_get_nolock(inode, di_bh, name_index,
                        "", value, retval);
    }

    if (retval > 0)
        acl = ocfs2_acl_from_xattr(value, retval);
    else if (retval == -ENODATA || retval == 0)
        acl = NULL;
    else
        acl = ERR_PTR(retval);

    kfree(value);

    return acl;
}


/*
 * Get posix acl.
 */
static struct posix_acl *ocfs2_get_acl(struct inode *inode, int type)
{
    struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
    struct buffer_head *di_bh = NULL;
    struct posix_acl *acl;
    int ret;

    if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
        return NULL;

    ret = ocfs2_inode_lock(inode, &di_bh, 0);
    if (ret < 0) {
        mlog_errno(ret);
        acl = ERR_PTR(ret);
        return acl;
    }

    acl = ocfs2_get_acl_nolock(inode, type, di_bh);

    ocfs2_inode_unlock(inode, 0);

    brelse(di_bh);

    return acl;
}

/*
 * Helper function to set i_mode in memory and disk. Some call paths
 * will not have di_bh or a journal handle to pass, in which case it
 * will create it's own.
 */
static int ocfs2_acl_set_mode(struct inode *inode, struct buffer_head *di_bh,
                  handle_t *handle, umode_t new_mode)
{
    int ret, commit_handle = 0;
    struct ocfs2_dinode *di;

    if (di_bh == NULL) {
        ret = ocfs2_read_inode_block(inode, &di_bh);
        if (ret) {
            mlog_errno(ret);
            goto out;
        }
    } else
        get_bh(di_bh);

    if (handle == NULL) {
        handle = ocfs2_start_trans(OCFS2_SB(inode->i_sb),
                       OCFS2_INODE_UPDATE_CREDITS);
        if (IS_ERR(handle)) {
            ret = PTR_ERR(handle);
            mlog_errno(ret);
            goto out_brelse;
        }

        commit_handle = 1;
    }

    di = (struct ocfs2_dinode *)di_bh->b_data;
    ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh,
                      OCFS2_JOURNAL_ACCESS_WRITE);
    if (ret) {
        mlog_errno(ret);
        goto out_commit;
    }

    inode->i_mode = new_mode;
    inode->i_ctime = CURRENT_TIME;
    di->i_mode = cpu_to_le16(inode->i_mode);
    di->i_ctime = cpu_to_le64(inode->i_ctime.tv_sec);
    di->i_ctime_nsec = cpu_to_le32(inode->i_ctime.tv_nsec);

    ocfs2_journal_dirty(handle, di_bh);

out_commit:
    if (commit_handle)
        ocfs2_commit_trans(OCFS2_SB(inode->i_sb), handle);
out_brelse:
    brelse(di_bh);
out:
    return ret;
}

/*
 * Set the access or default ACL of an inode.
 */
static int ocfs2_set_acl(handle_t *handle,
             struct inode *inode,
             struct buffer_head *di_bh,
             int type,
             struct posix_acl *acl,
             struct ocfs2_alloc_context *meta_ac,
             struct ocfs2_alloc_context *data_ac)
{
    int name_index;
    void *value = NULL;
    size_t size = 0;
    int ret;

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

    switch (type) {
    case ACL_TYPE_ACCESS:
        name_index = OCFS2_XATTR_INDEX_POSIX_ACL_ACCESS;
        if (acl) {
            umode_t mode = inode->i_mode;
            ret = posix_acl_equiv_mode(acl, &mode);
            if (ret < 0)
                return ret;
            else {
                if (ret == 0)
                    acl = NULL;

                ret = ocfs2_acl_set_mode(inode, di_bh,
                             handle, mode);
                if (ret)
                    return ret;

            }
        }
        break;
    case ACL_TYPE_DEFAULT:
        name_index = OCFS2_XATTR_INDEX_POSIX_ACL_DEFAULT;
        if (!S_ISDIR(inode->i_mode))
            return acl ? -EACCES : 0;
        break;
    default:
        return -EINVAL;
    }

    if (acl) {
        value = ocfs2_acl_to_xattr(acl, &size);
        if (IS_ERR(value))
            return (int)PTR_ERR(value);
    }

    if (handle)
        ret = ocfs2_xattr_set_handle(handle, inode, di_bh, name_index,
                         "", value, size, 0,
                         meta_ac, data_ac);
    else
        ret = ocfs2_xattr_set(inode, name_index, "", value, size, 0);

    kfree(value);

    return ret;
}

struct posix_acl *ocfs2_iop_get_acl(struct inode *inode, int type)
{
    struct ocfs2_super *osb;
    struct buffer_head *di_bh = NULL;
    struct posix_acl *acl;
    int ret = -EAGAIN;

    osb = OCFS2_SB(inode->i_sb);
    if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
        return NULL;

    ret = ocfs2_read_inode_block(inode, &di_bh);
    if (ret < 0)
        return ERR_PTR(ret);

    acl = ocfs2_get_acl_nolock(inode, type, di_bh);

    brelse(di_bh);

    return acl;
}

int ocfs2_acl_chmod(struct inode *inode)
{
    struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
    struct posix_acl *acl;
    int ret;

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

    if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
        return 0;

    acl = ocfs2_get_acl(inode, ACL_TYPE_ACCESS);
    if (IS_ERR(acl) || !acl)
        return PTR_ERR(acl);
    ret = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
    if (ret)
        return ret;
    ret = ocfs2_set_acl(NULL, inode, NULL, ACL_TYPE_ACCESS,
                acl, NULL, NULL);
    posix_acl_release(acl);
    return ret;
}

/*
 * Initialize the ACLs of a new inode. If parent directory has default ACL,
 * then clone to new inode. Called from ocfs2_mknod.
 */
int ocfs2_init_acl(handle_t *handle,
           struct inode *inode,
           struct inode *dir,
           struct buffer_head *di_bh,
           struct buffer_head *dir_bh,
           struct ocfs2_alloc_context *meta_ac,
           struct ocfs2_alloc_context *data_ac)
{
    struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
    struct posix_acl *acl = NULL;
    int ret = 0, ret2;
    umode_t mode;

    if (!S_ISLNK(inode->i_mode)) {
        if (osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL) {
            acl = ocfs2_get_acl_nolock(dir, ACL_TYPE_DEFAULT,
                           dir_bh);
            if (IS_ERR(acl))
                return PTR_ERR(acl);
        }
        if (!acl) {
            mode = inode->i_mode & ~current_umask();
            ret = ocfs2_acl_set_mode(inode, di_bh, handle, mode);
            if (ret) {
                mlog_errno(ret);
                goto cleanup;
            }
        }
    }
    if ((osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL) && acl) {
        if (S_ISDIR(inode->i_mode)) {
            ret = ocfs2_set_acl(handle, inode, di_bh,
                        ACL_TYPE_DEFAULT, acl,
                        meta_ac, data_ac);
            if (ret)
                goto cleanup;
        }
        mode = inode->i_mode;
        ret = posix_acl_create(&acl, GFP_NOFS, &mode);
        if (ret < 0)
            return ret;

        ret2 = ocfs2_acl_set_mode(inode, di_bh, handle, mode);
        if (ret2) {
            mlog_errno(ret2);
            ret = ret2;
            goto cleanup;
        }
        if (ret > 0) {
            ret = ocfs2_set_acl(handle, inode,
                        di_bh, ACL_TYPE_ACCESS,
                        acl, meta_ac, data_ac);
        }
    }
cleanup:
    posix_acl_release(acl);
    return ret;
}

static size_t ocfs2_xattr_list_acl_access(struct dentry *dentry,
                      char *list,
                      size_t list_len,
                      const char *name,
                      size_t name_len,
                      int type)
{
    struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);
    const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);

    if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
        return 0;

    if (list && size <= list_len)
        memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
    return size;
}

static size_t ocfs2_xattr_list_acl_default(struct dentry *dentry,
                       char *list,
                       size_t list_len,
                       const char *name,
                       size_t name_len,
                       int type)
{
    struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);
    const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);

    if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
        return 0;

    if (list && size <= list_len)
        memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
    return size;
}

static int ocfs2_xattr_get_acl(struct dentry *dentry, const char *name,
        void *buffer, size_t size, int type)
{
    struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);
    struct posix_acl *acl;
    int ret;

    if (strcmp(name, "") != 0)
        return -EINVAL;
    if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
        return -EOPNOTSUPP;

    acl = ocfs2_get_acl(dentry->d_inode, type);
    if (IS_ERR(acl))
        return PTR_ERR(acl);
    if (acl == NULL)
        return -ENODATA;
    ret = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
    posix_acl_release(acl);

    return ret;
}

static int ocfs2_xattr_set_acl(struct dentry *dentry, const char *name,
        const void *value, size_t size, int flags, int type)
{
    struct inode *inode = dentry->d_inode;
    struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
    struct posix_acl *acl;
    int ret = 0;

    if (strcmp(name, "") != 0)
        return -EINVAL;
    if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
        return -EOPNOTSUPP;

    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);
        else if (acl) {
            ret = posix_acl_valid(acl);
            if (ret)
                goto cleanup;
        }
    } else
        acl = NULL;

    ret = ocfs2_set_acl(NULL, inode, NULL, type, acl, NULL, NULL);

cleanup:
    posix_acl_release(acl);
    return ret;
}

const struct xattr_handler ocfs2_xattr_acl_access_handler = {
    .prefix = POSIX_ACL_XATTR_ACCESS,
    .flags  = ACL_TYPE_ACCESS,
    .list   = ocfs2_xattr_list_acl_access,
    .get    = ocfs2_xattr_get_acl,
    .set    = ocfs2_xattr_set_acl,
};

const struct xattr_handler ocfs2_xattr_acl_default_handler = {
    .prefix = POSIX_ACL_XATTR_DEFAULT,
    .flags  = ACL_TYPE_DEFAULT,
    .list   = ocfs2_xattr_list_acl_default,
    .get    = ocfs2_xattr_get_acl,
    .set    = ocfs2_xattr_set_acl,
};