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
  21 long 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);
  87 setflags_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
 159 long 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