LXR linux/fs/ext2/ioctl.c

   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 <linux/smp_lock.h>
  17#include <asm/current.h>
  18#include <asm/uaccess.h>
  19
  20
  21long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
  22{
  23        struct inode *inode = filp->f_dentry->d_inode;
  24        struct ext2_inode_info *ei = EXT2_I(inode);
  25        unsigned int flags;
  26        unsigned short rsv_window_size;
  27        int ret;
  28
  29        ext2_debug ("cmd = %u, arg = %lu\n", cmd, arg);
  30
  31        switch (cmd) {
  32        case EXT2_IOC_GETFLAGS:
  33                ext2_get_inode_flags(ei);
  34                flags = ei->i_flags & EXT2_FL_USER_VISIBLE;
  35                return put_user(flags, (int __user *) arg);
  36        case EXT2_IOC_SETFLAGS: {
  37                unsigned int oldflags;
  38
  39                ret = mnt_want_write(filp->f_path.mnt);
  40                if (ret)
  41                        return ret;
  42
  43                if (!is_owner_or_cap(inode)) {
  44                        ret = -EACCES;
  45                        goto setflags_out;
  46                }
  47
  48                if (get_user(flags, (int __user *) arg)) {
  49                        ret = -EFAULT;
  50                        goto setflags_out;
  51                }
  52
  53                if (!S_ISDIR(inode->i_mode))
  54                        flags &= ~EXT2_DIRSYNC_FL;
  55
  56                mutex_lock(&inode->i_mutex);
  57                /* Is it quota file? Do not allow user to mess with it */
  58                if (IS_NOQUOTA(inode)) {
  59                        mutex_unlock(&inode->i_mutex);
  60                        ret = -EPERM;
  61                        goto setflags_out;
  62                }
  63                oldflags = ei->i_flags;
  64
  65                /*
  66                 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
  67                 * the relevant capability.
  68                 *
  69                 * This test looks nicer. Thanks to Pauline Middelink
  70                 */
  71                if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
  72                        if (!capable(CAP_LINUX_IMMUTABLE)) {
  73                                mutex_unlock(&inode->i_mutex);
  74                                ret = -EPERM;
  75                                goto setflags_out;
  76                        }
  77                }
  78
  79                flags = flags & EXT2_FL_USER_MODIFIABLE;
  80                flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
  81                ei->i_flags = flags;
  82                mutex_unlock(&inode->i_mutex);
  83
  84                ext2_set_inode_flags(inode);
  85                inode->i_ctime = CURRENT_TIME_SEC;
  86                mark_inode_dirty(inode);
  87setflags_out:
  88                mnt_drop_write(filp->f_path.mnt);
  89                return ret;
  90        }
  91        case EXT2_IOC_GETVERSION:
  92                return put_user(inode->i_generation, (int __user *) arg);
  93        case EXT2_IOC_SETVERSION:
  94                if (!is_owner_or_cap(inode))
  95                        return -EPERM;
  96                ret = mnt_want_write(filp->f_path.mnt);
  97                if (ret)
  98                        return ret;
  99                if (get_user(inode->i_generation, (int __user *) arg)) {
 100                        ret = -EFAULT;
 101                } else {
 102                        inode->i_ctime = CURRENT_TIME_SEC;
 103                        mark_inode_dirty(inode);
 104                }
 105                mnt_drop_write(filp->f_path.mnt);
 106                return ret;
 107        case EXT2_IOC_GETRSVSZ:
 108                if (test_opt(inode->i_sb, RESERVATION)
 109                        && S_ISREG(inode->i_mode)
 110                        && ei->i_block_alloc_info) {
 111                        rsv_window_size = ei->i_block_alloc_info->rsv_window_node.rsv_goal_size;
 112                        return put_user(rsv_window_size, (int __user *)arg);
 113                }
 114                return -ENOTTY;
 115        case EXT2_IOC_SETRSVSZ: {
 116
 117                if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
 118                        return -ENOTTY;
 119
 120                if (!is_owner_or_cap(inode))
 121                        return -EACCES;
 122
 123                if (get_user(rsv_window_size, (int __user *)arg))
 124                        return -EFAULT;
 125
 126                ret = mnt_want_write(filp->f_path.mnt);
 127                if (ret)
 128                        return ret;
 129
 130                if (rsv_window_size > EXT2_MAX_RESERVE_BLOCKS)
 131                        rsv_window_size = EXT2_MAX_RESERVE_BLOCKS;
 132
 133                /*
 134                 * need to allocate reservation structure for this inode
 135                 * before set the window size
 136                 */
 137                /*
 138                 * XXX What lock should protect the rsv_goal_size?
 139                 * Accessed in ext2_get_block only.  ext3 uses i_truncate.
 140                 */
 141                mutex_lock(&ei->truncate_mutex);
 142                if (!ei->i_block_alloc_info)
 143                        ext2_init_block_alloc_info(inode);
 144
 145                if (ei->i_block_alloc_info){
 146                        struct ext2_reserve_window_node *rsv = &ei->i_block_alloc_info->rsv_window_node;
 147                        rsv->rsv_goal_size = rsv_window_size;
 148                }
 149                mutex_unlock(&ei->truncate_mutex);
 150                mnt_drop_write(filp->f_path.mnt);
 151                return 0;
 152        }
 153        default:
 154                return -ENOTTY;
 155        }
 156}
 157
 158#ifdef CONFIG_COMPAT
 159long ext2_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 160{
 161        /* These are just misnamed, they actually get/put from/to user an int */
 162        switch (cmd) {
 163        case EXT2_IOC32_GETFLAGS:
 164                cmd = EXT2_IOC_GETFLAGS;
 165                break;
 166        case EXT2_IOC32_SETFLAGS:
 167                cmd = EXT2_IOC_SETFLAGS;
 168                break;
 169        case EXT2_IOC32_GETVERSION:
 170                cmd = EXT2_IOC_GETVERSION;
 171                break;
 172        case EXT2_IOC32_SETVERSION:
 173                cmd = EXT2_IOC_SETVERSION;
 174                break;
 175        default:
 176                return -ENOIOCTLCMD;
 177        }
 178        return ext2_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
 179}
 180#endif
 181