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 <asm/uaccess.h>
  18
  19
  20 long 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);
  85 setflags_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
 157 long 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