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                 flags = ext2_mask_flags(inode->i_mode, flags);
  54
  55                 mutex_lock(&inode->i_mutex);
  56                 /* Is it quota file? Do not allow user to mess with it */
  57                 if (IS_NOQUOTA(inode)) {
  58                         mutex_unlock(&inode->i_mutex);
  59                         ret = -EPERM;
  60                         goto setflags_out;
  61                 }
  62                 oldflags = ei->i_flags;
  63
  64                 /*
  65                  * The IMMUTABLE and APPEND_ONLY flags can only be changed by
  66                  * the relevant capability.
  67                  *
  68                  * This test looks nicer. Thanks to Pauline Middelink
  69                  */
  70                 if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
  71                         if (!capable(CAP_LINUX_IMMUTABLE)) {
  72                                 mutex_unlock(&inode->i_mutex);
  73                                 ret = -EPERM;
  74                                 goto setflags_out;
  75                         }
  76                 }
  77
  78                 flags = flags & EXT2_FL_USER_MODIFIABLE;
  79                 flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
  80                 ei->i_flags = flags;
  81                 mutex_unlock(&inode->i_mutex);
  82
  83                 ext2_set_inode_flags(inode);
  84                 inode->i_ctime = CURRENT_TIME_SEC;
  85                 mark_inode_dirty(inode);
  86 setflags_out:
  87                 mnt_drop_write(filp->f_path.mnt);
  88                 return ret;
  89         }
  90         case EXT2_IOC_GETVERSION:
  91                 return put_user(inode->i_generation, (int __user *) arg);
  92         case EXT2_IOC_SETVERSION:
  93                 if (!is_owner_or_cap(inode))
  94                         return -EPERM;
  95                 ret = mnt_want_write(filp->f_path.mnt);
  96                 if (ret)
  97                         return ret;
  98                 if (get_user(inode->i_generation, (int __user *) arg)) {
  99                         ret = -EFAULT;
 100                 } else {
 101                         inode->i_ctime = CURRENT_TIME_SEC;
 102                         mark_inode_dirty(inode);
 103                 }
 104                 mnt_drop_write(filp->f_path.mnt);
 105                 return ret;
 106         case EXT2_IOC_GETRSVSZ:
 107                 if (test_opt(inode->i_sb, RESERVATION)
 108                         && S_ISREG(inode->i_mode)
 109                         && ei->i_block_alloc_info) {
 110                         rsv_window_size = ei->i_block_alloc_info->rsv_window_node.rsv_goal_size;
 111                         return put_user(rsv_window_size, (int __user *)arg);
 112                 }
 113                 return -ENOTTY;
 114         case EXT2_IOC_SETRSVSZ: {
 115
 116                 if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
 117                         return -ENOTTY;
 118
 119                 if (!is_owner_or_cap(inode))
 120                         return -EACCES;
 121
 122                 if (get_user(rsv_window_size, (int __user *)arg))
 123                         return -EFAULT;
 124
 125                 ret = mnt_want_write(filp->f_path.mnt);
 126                 if (ret)
 127                         return ret;
 128
 129                 if (rsv_window_size > EXT2_MAX_RESERVE_BLOCKS)
 130                         rsv_window_size = EXT2_MAX_RESERVE_BLOCKS;
 131
 132                 /*
 133                  * need to allocate reservation structure for this inode
 134                  * before set the window size
 135                  */
 136                 /*
 137                  * XXX What lock should protect the rsv_goal_size?
 138                  * Accessed in ext2_get_block only.  ext3 uses i_truncate.
 139                  */
 140                 mutex_lock(&ei->truncate_mutex);
 141                 if (!ei->i_block_alloc_info)
 142                         ext2_init_block_alloc_info(inode);
 143
 144                 if (ei->i_block_alloc_info){
 145                         struct ext2_reserve_window_node *rsv = &ei->i_block_alloc_info->rsv_window_node;
 146                         rsv->rsv_goal_size = rsv_window_size;
 147                 }
 148                 mutex_unlock(&ei->truncate_mutex);
 149                 mnt_drop_write(filp->f_path.mnt);
 150                 return 0;
 151         }
 152         default:
 153                 return -ENOTTY;
 154         }
 155 }
 156
 157 #ifdef CONFIG_COMPAT
 158 long ext2_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 159 {
 160         /* These are just misnamed, they actually get/put from/to user an int */
 161         switch (cmd) {
 162         case EXT2_IOC32_GETFLAGS:
 163                 cmd = EXT2_IOC_GETFLAGS;
 164                 break;
 165         case EXT2_IOC32_SETFLAGS:
 166                 cmd = EXT2_IOC_SETFLAGS;
 167                 break;
 168         case EXT2_IOC32_GETVERSION:
 169                 cmd = EXT2_IOC_GETVERSION;
 170                 break;
 171         case EXT2_IOC32_SETVERSION:
 172                 cmd = EXT2_IOC_SETVERSION;
 173                 break;
 174         default:
 175                 return -ENOIOCTLCMD;
 176         }
 177         return ext2_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
 178 }
 179 #endif