ioctl.c

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/*
 * linux/fs/ext2/ioctl.c
 *
 * Copyright (C) 1993, 1994, 1995
 * Remy Card ([email protected])
 * Laboratoire MASI - Institut Blaise Pascal
 * Universite Pierre et Marie Curie (Paris VI)
 */

#include "ext2.h"
#include <linux/capability.h>
#include <linux/time.h>
#include <linux/sched.h>
#include <linux/compat.h>
#include <linux/mount.h>
#include <asm/current.h>
#include <asm/uaccess.h>


long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
    struct inode *inode = filp->f_dentry->d_inode;
    struct ext2_inode_info *ei = EXT2_I(inode);
    unsigned int flags;
    unsigned short rsv_window_size;
    int ret;

    ext2_debug ("cmd = %u, arg = %lu\n", cmd, arg);

    switch (cmd) {
    case EXT2_IOC_GETFLAGS:
        ext2_get_inode_flags(ei);
        flags = ei->i_flags & EXT2_FL_USER_VISIBLE;
        return put_user(flags, (int __user *) arg);
    case EXT2_IOC_SETFLAGS: {
        unsigned int oldflags;

        ret = mnt_want_write_file(filp);
        if (ret)
            return ret;

        if (!inode_owner_or_capable(inode)) {
            ret = -EACCES;
            goto setflags_out;
        }

        if (get_user(flags, (int __user *) arg)) {
            ret = -EFAULT;
            goto setflags_out;
        }

        flags = ext2_mask_flags(inode->i_mode, flags);

        mutex_lock(&inode->i_mutex);
        /* Is it quota file? Do not allow user to mess with it */
        if (IS_NOQUOTA(inode)) {
            mutex_unlock(&inode->i_mutex);
            ret = -EPERM;
            goto setflags_out;
        }
        oldflags = ei->i_flags;

        /*
         * The IMMUTABLE and APPEND_ONLY flags can only be changed by
         * the relevant capability.
         *
         * This test looks nicer. Thanks to Pauline Middelink
         */
        if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
            if (!capable(CAP_LINUX_IMMUTABLE)) {
                mutex_unlock(&inode->i_mutex);
                ret = -EPERM;
                goto setflags_out;
            }
        }

        flags = flags & EXT2_FL_USER_MODIFIABLE;
        flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
        ei->i_flags = flags;

        ext2_set_inode_flags(inode);
        inode->i_ctime = CURRENT_TIME_SEC;
        mutex_unlock(&inode->i_mutex);

        mark_inode_dirty(inode);
setflags_out:
        mnt_drop_write_file(filp);
        return ret;
    }
    case EXT2_IOC_GETVERSION:
        return put_user(inode->i_generation, (int __user *) arg);
    case EXT2_IOC_SETVERSION: {
        __u32 generation;

        if (!inode_owner_or_capable(inode))
            return -EPERM;
        ret = mnt_want_write_file(filp);
        if (ret)
            return ret;
        if (get_user(generation, (int __user *) arg)) {
            ret = -EFAULT;
            goto setversion_out;
        }

        mutex_lock(&inode->i_mutex);
        inode->i_ctime = CURRENT_TIME_SEC;
        inode->i_generation = generation;
        mutex_unlock(&inode->i_mutex);

        mark_inode_dirty(inode);
setversion_out:
        mnt_drop_write_file(filp);
        return ret;
    }
    case EXT2_IOC_GETRSVSZ:
        if (test_opt(inode->i_sb, RESERVATION)
            && S_ISREG(inode->i_mode)
            && ei->i_block_alloc_info) {
            rsv_window_size = ei->i_block_alloc_info->rsv_window_node.rsv_goal_size;
            return put_user(rsv_window_size, (int __user *)arg);
        }
        return -ENOTTY;
    case EXT2_IOC_SETRSVSZ: {

        if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
            return -ENOTTY;

        if (!inode_owner_or_capable(inode))
            return -EACCES;

        if (get_user(rsv_window_size, (int __user *)arg))
            return -EFAULT;

        ret = mnt_want_write_file(filp);
        if (ret)
            return ret;

        if (rsv_window_size > EXT2_MAX_RESERVE_BLOCKS)
            rsv_window_size = EXT2_MAX_RESERVE_BLOCKS;

        /*
         * need to allocate reservation structure for this inode
         * before set the window size
         */
        /*
         * XXX What lock should protect the rsv_goal_size?
         * Accessed in ext2_get_block only.  ext3 uses i_truncate.
         */
        mutex_lock(&ei->truncate_mutex);
        if (!ei->i_block_alloc_info)
            ext2_init_block_alloc_info(inode);

        if (ei->i_block_alloc_info){
            struct ext2_reserve_window_node *rsv = &ei->i_block_alloc_info->rsv_window_node;
            rsv->rsv_goal_size = rsv_window_size;
        }
        mutex_unlock(&ei->truncate_mutex);
        mnt_drop_write_file(filp);
        return 0;
    }
    default:
        return -ENOTTY;
    }
}

#ifdef CONFIG_COMPAT
long ext2_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    /* These are just misnamed, they actually get/put from/to user an int */
    switch (cmd) {
    case EXT2_IOC32_GETFLAGS:
        cmd = EXT2_IOC_GETFLAGS;
        break;
    case EXT2_IOC32_SETFLAGS:
        cmd = EXT2_IOC_SETFLAGS;
        break;
    case EXT2_IOC32_GETVERSION:
        cmd = EXT2_IOC_GETVERSION;
        break;
    case EXT2_IOC32_SETVERSION:
        cmd = EXT2_IOC_SETVERSION;
        break;
    default:
        return -ENOIOCTLCMD;
    }
    return ext2_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
}
#endif