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 <asm/current.h>
  17 #include <linux/uaccess.h>
  18
  19
  20 long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
  21 {
  22         struct inode *inode = file_inode(filp);
  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                 flags = ei->i_flags & EXT2_FL_USER_VISIBLE;
  33                 return put_user(flags, (int __user *) arg);
  34         case EXT2_IOC_SETFLAGS: {
  35                 unsigned int oldflags;
  36
  37                 ret = mnt_want_write_file(filp);
  38                 if (ret)
  39                         return ret;
  40
  41                 if (!inode_owner_or_capable(inode)) {
  42                         ret = -EACCES;
  43                         goto setflags_out;
  44                 }
  45
  46                 if (get_user(flags, (int __user *) arg)) {
  47                         ret = -EFAULT;
  48                         goto setflags_out;
  49                 }
  50
  51                 flags = ext2_mask_flags(inode->i_mode, flags);
  52
  53                 inode_lock(inode);
  54                 /* Is it quota file? Do not allow user to mess with it */
  55                 if (IS_NOQUOTA(inode)) {
  56                         inode_unlock(inode);
  57                         ret = -EPERM;
  58                         goto setflags_out;
  59                 }
  60                 oldflags = ei->i_flags;
  61
  62                 /*
  63                  * The IMMUTABLE and APPEND_ONLY flags can only be changed by
  64                  * the relevant capability.
  65                  *
  66                  * This test looks nicer. Thanks to Pauline Middelink
  67                  */
  68                 if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
  69                         if (!capable(CAP_LINUX_IMMUTABLE)) {
  70                                 inode_unlock(inode);
  71                                 ret = -EPERM;
  72                                 goto setflags_out;
  73                         }
  74                 }
  75
  76                 flags = flags & EXT2_FL_USER_MODIFIABLE;
  77                 flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
  78                 ei->i_flags = flags;
  79
  80                 ext2_set_inode_flags(inode);
  81                 inode->i_ctime = current_time(inode);
  82                 inode_unlock(inode);
  83
  84                 mark_inode_dirty(inode);
  85 setflags_out:
  86                 mnt_drop_write_file(filp);
  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                 __u32 generation;
  93
  94                 if (!inode_owner_or_capable(inode))
  95                         return -EPERM;
  96                 ret = mnt_want_write_file(filp);
  97                 if (ret)
  98                         return ret;
  99                 if (get_user(generation, (int __user *) arg)) {
 100                         ret = -EFAULT;
 101                         goto setversion_out;
 102                 }
 103
 104                 inode_lock(inode);
 105                 inode->i_ctime = current_time(inode);
 106                 inode->i_generation = generation;
 107                 inode_unlock(inode);
 108
 109                 mark_inode_dirty(inode);
 110 setversion_out:
 111                 mnt_drop_write_file(filp);
 112                 return ret;
 113         }
 114         case EXT2_IOC_GETRSVSZ:
 115                 if (test_opt(inode->i_sb, RESERVATION)
 116                         && S_ISREG(inode->i_mode)
 117                         && ei->i_block_alloc_info) {
 118                         rsv_window_size = ei->i_block_alloc_info->rsv_window_node.rsv_goal_size;
 119                         return put_user(rsv_window_size, (int __user *)arg);
 120                 }
 121                 return -ENOTTY;
 122         case EXT2_IOC_SETRSVSZ: {
 123
 124                 if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
 125                         return -ENOTTY;
 126
 127                 if (!inode_owner_or_capable(inode))
 128                         return -EACCES;
 129
 130                 if (get_user(rsv_window_size, (int __user *)arg))
 131                         return -EFAULT;
 132
 133                 ret = mnt_want_write_file(filp);
 134                 if (ret)
 135                         return ret;
 136
 137                 if (rsv_window_size > EXT2_MAX_RESERVE_BLOCKS)
 138                         rsv_window_size = EXT2_MAX_RESERVE_BLOCKS;
 139
 140                 /*
 141                  * need to allocate reservation structure for this inode
 142                  * before set the window size
 143                  */
 144                 /*
 145                  * XXX What lock should protect the rsv_goal_size?
 146                  * Accessed in ext2_get_block only.  ext3 uses i_truncate.
 147                  */
 148                 mutex_lock(&ei->truncate_mutex);
 149                 if (!ei->i_block_alloc_info)
 150                         ext2_init_block_alloc_info(inode);
 151
 152                 if (ei->i_block_alloc_info){
 153                         struct ext2_reserve_window_node *rsv = &ei->i_block_alloc_info->rsv_window_node;
 154                         rsv->rsv_goal_size = rsv_window_size;
 155                 }
 156                 mutex_unlock(&ei->truncate_mutex);
 157                 mnt_drop_write_file(filp);
 158                 return 0;
 159         }
 160         default:
 161                 return -ENOTTY;
 162         }
 163 }
 164
 165 #ifdef CONFIG_COMPAT
 166 long ext2_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 167 {
 168         /* These are just misnamed, they actually get/put from/to user an int */
 169         switch (cmd) {
 170         case EXT2_IOC32_GETFLAGS:
 171                 cmd = EXT2_IOC_GETFLAGS;
 172                 break;
 173         case EXT2_IOC32_SETFLAGS:
 174                 cmd = EXT2_IOC_SETFLAGS;
 175                 break;
 176         case EXT2_IOC32_GETVERSION:
 177                 cmd = EXT2_IOC_GETVERSION;
 178                 break;
 179         case EXT2_IOC32_SETVERSION:
 180                 cmd = EXT2_IOC_SETVERSION;
 181                 break;
 182         default:
 183                 return -ENOIOCTLCMD;
 184         }
 185         return ext2_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
 186 }
 187 #endif