linux/fs/ext2/ioctl.c
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   1/*
   2 * linux/fs/ext2/ioctl.c
   3 *
   4 * Copyright (C) 1993, 1994, 1995
   5 * Remy Card (card@masi.ibp.fr)
   6 * Laboratoire MASI - Institut Blaise Pascal
   7 * Universite Pierre et Marie Curie (Paris VI)
   8 */
   9
  10#include "ext2.h"
  11#include <linux/capability.h>
  12#include <linux/time.h>
  13#include <linux/sched.h>
  14#include <linux/compat.h>
  15#include <linux/mount.h>
  16#include <asm/current.h>
  17#include <asm/uaccess.h>
  18
  19
  20long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
  21{
  22        struct inode *inode = filp->f_dentry->d_inode;
  23        struct ext2_inode_info *ei = EXT2_I(inode);
  24        unsigned int flags;
  25        unsigned short rsv_window_size;
  26        int ret;
  27
  28        ext2_debug ("cmd = %u, arg = %lu\n", cmd, arg);
  29
  30        switch (cmd) {
  31        case EXT2_IOC_GETFLAGS:
  32                ext2_get_inode_flags(ei);
  33                flags = ei->i_flags & EXT2_FL_USER_VISIBLE;
  34                return put_user(flags, (int __user *) arg);
  35        case EXT2_IOC_SETFLAGS: {
  36                unsigned int oldflags;
  37
  38                ret = mnt_want_write(filp->f_path.mnt);
  39                if (ret)
  40                        return ret;
  41
  42                if (!is_owner_or_cap(inode)) {
  43                        ret = -EACCES;
  44                        goto setflags_out;
  45                }
  46
  47                if (get_user(flags, (int __user *) arg)) {
  48                        ret = -EFAULT;
  49                        goto setflags_out;
  50                }
  51
  52                flags = ext2_mask_flags(inode->i_mode, flags);
  53
  54                mutex_lock(&inode->i_mutex);
  55                /* Is it quota file? Do not allow user to mess with it */
  56                if (IS_NOQUOTA(inode)) {
  57                        mutex_unlock(&inode->i_mutex);
  58                        ret = -EPERM;
  59                        goto setflags_out;
  60                }
  61                oldflags = ei->i_flags;
  62
  63                /*
  64                 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
  65                 * the relevant capability.
  66                 *
  67                 * This test looks nicer. Thanks to Pauline Middelink
  68                 */
  69                if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
  70                        if (!capable(CAP_LINUX_IMMUTABLE)) {
  71                                mutex_unlock(&inode->i_mutex);
  72                                ret = -EPERM;
  73                                goto setflags_out;
  74                        }
  75                }
  76
  77                flags = flags & EXT2_FL_USER_MODIFIABLE;
  78                flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
  79                ei->i_flags = flags;
  80                mutex_unlock(&inode->i_mutex);
  81
  82                ext2_set_inode_flags(inode);
  83                inode->i_ctime = CURRENT_TIME_SEC;
  84                mark_inode_dirty(inode);
  85setflags_out:
  86                mnt_drop_write(filp->f_path.mnt);
  87                return ret;
  88        }
  89        case EXT2_IOC_GETVERSION:
  90                return put_user(inode->i_generation, (int __user *) arg);
  91        case EXT2_IOC_SETVERSION:
  92                if (!is_owner_or_cap(inode))
  93                        return -EPERM;
  94                ret = mnt_want_write(filp->f_path.mnt);
  95                if (ret)
  96                        return ret;
  97                if (get_user(inode->i_generation, (int __user *) arg)) {
  98                        ret = -EFAULT;
  99                } else {
 100                        inode->i_ctime = CURRENT_TIME_SEC;
 101                        mark_inode_dirty(inode);
 102                }
 103                mnt_drop_write(filp->f_path.mnt);
 104                return ret;
 105        case EXT2_IOC_GETRSVSZ:
 106                if (test_opt(inode->i_sb, RESERVATION)
 107                        && S_ISREG(inode->i_mode)
 108                        && ei->i_block_alloc_info) {
 109                        rsv_window_size = ei->i_block_alloc_info->rsv_window_node.rsv_goal_size;
 110                        return put_user(rsv_window_size, (int __user *)arg);
 111                }
 112                return -ENOTTY;
 113        case EXT2_IOC_SETRSVSZ: {
 114
 115                if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
 116                        return -ENOTTY;
 117
 118                if (!is_owner_or_cap(inode))
 119                        return -EACCES;
 120
 121                if (get_user(rsv_window_size, (int __user *)arg))
 122                        return -EFAULT;
 123
 124                ret = mnt_want_write(filp->f_path.mnt);
 125                if (ret)
 126                        return ret;
 127
 128                if (rsv_window_size > EXT2_MAX_RESERVE_BLOCKS)
 129                        rsv_window_size = EXT2_MAX_RESERVE_BLOCKS;
 130
 131                /*
 132                 * need to allocate reservation structure for this inode
 133                 * before set the window size
 134                 */
 135                /*
 136                 * XXX What lock should protect the rsv_goal_size?
 137                 * Accessed in ext2_get_block only.  ext3 uses i_truncate.
 138                 */
 139                mutex_lock(&ei->truncate_mutex);
 140                if (!ei->i_block_alloc_info)
 141                        ext2_init_block_alloc_info(inode);
 142
 143                if (ei->i_block_alloc_info){
 144                        struct ext2_reserve_window_node *rsv = &ei->i_block_alloc_info->rsv_window_node;
 145                        rsv->rsv_goal_size = rsv_window_size;
 146                }
 147                mutex_unlock(&ei->truncate_mutex);
 148                mnt_drop_write(filp->f_path.mnt);
 149                return 0;
 150        }
 151        default:
 152                return -ENOTTY;
 153        }
 154}
 155
 156#ifdef CONFIG_COMPAT
 157long ext2_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 158{
 159        /* These are just misnamed, they actually get/put from/to user an int */
 160        switch (cmd) {
 161        case EXT2_IOC32_GETFLAGS:
 162                cmd = EXT2_IOC_GETFLAGS;
 163                break;
 164        case EXT2_IOC32_SETFLAGS:
 165                cmd = EXT2_IOC_SETFLAGS;
 166                break;
 167        case EXT2_IOC32_GETVERSION:
 168                cmd = EXT2_IOC_GETVERSION;
 169                break;
 170        case EXT2_IOC32_SETVERSION:
 171                cmd = EXT2_IOC_SETVERSION;
 172                break;
 173        default:
 174                return -ENOIOCTLCMD;
 175        }
 176        return ext2_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
 177}
 178#endif
 179