fs/ubifs/ioctl.c

   1 /*
   2  * This file is part of UBIFS.
   3  *
   4  * Copyright (C) 2006-2008 Nokia Corporation.
   5  * Copyright (C) 2006, 2007 University of Szeged, Hungary
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License version 2 as published by
   9  * the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along with
  17  * this program; if not, write to the Free Software Foundation, Inc., 51
  18  * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  *
  20  * Authors: Zoltan Sogor
  21  *          Artem Bityutskiy (Битюцкий Артём)
  22  *          Adrian Hunter
  23  */
  24
  25 /* This file implements EXT2-compatible extended attribute ioctl() calls */
  26
  27 #include <linux/compat.h>
  28 #include <linux/mount.h>
  29 #include "ubifs.h"
  30
  31 /**
  32  * ubifs_set_inode_flags - set VFS inode flags.
  33  * @inode: VFS inode to set flags for
  34  *
  35  * This function propagates flags from UBIFS inode object to VFS inode object.
  36  */
  37 void ubifs_set_inode_flags(struct inode *inode)
  38 {
  39         unsigned int flags = ubifs_inode(inode)->flags;
  40
  41         inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_DIRSYNC);
  42         if (flags & UBIFS_SYNC_FL)
  43                 inode->i_flags |= S_SYNC;
  44         if (flags & UBIFS_APPEND_FL)
  45                 inode->i_flags |= S_APPEND;
  46         if (flags & UBIFS_IMMUTABLE_FL)
  47                 inode->i_flags |= S_IMMUTABLE;
  48         if (flags & UBIFS_DIRSYNC_FL)
  49                 inode->i_flags |= S_DIRSYNC;
  50 }
  51
  52 /*
  53  * ioctl2ubifs - convert ioctl inode flags to UBIFS inode flags.
  54  * @ioctl_flags: flags to convert
  55  *
  56  * This function convert ioctl flags (@FS_COMPR_FL, etc) to UBIFS inode flags
  57  * (@UBIFS_COMPR_FL, etc).
  58  */
  59 static int ioctl2ubifs(int ioctl_flags)
  60 {
  61         int ubifs_flags = 0;
  62
  63         if (ioctl_flags & FS_COMPR_FL)
  64                 ubifs_flags |= UBIFS_COMPR_FL;
  65         if (ioctl_flags & FS_SYNC_FL)
  66                 ubifs_flags |= UBIFS_SYNC_FL;
  67         if (ioctl_flags & FS_APPEND_FL)
  68                 ubifs_flags |= UBIFS_APPEND_FL;
  69         if (ioctl_flags & FS_IMMUTABLE_FL)
  70                 ubifs_flags |= UBIFS_IMMUTABLE_FL;
  71         if (ioctl_flags & FS_DIRSYNC_FL)
  72                 ubifs_flags |= UBIFS_DIRSYNC_FL;
  73
  74         return ubifs_flags;
  75 }
  76
  77 /*
  78  * ubifs2ioctl - convert UBIFS inode flags to ioctl inode flags.
  79  * @ubifs_flags: flags to convert
  80  *
  81  * This function convert UBIFS (@UBIFS_COMPR_FL, etc) to ioctl flags
  82  * (@FS_COMPR_FL, etc).
  83  */
  84 static int ubifs2ioctl(int ubifs_flags)
  85 {
  86         int ioctl_flags = 0;
  87
  88         if (ubifs_flags & UBIFS_COMPR_FL)
  89                 ioctl_flags |= FS_COMPR_FL;
  90         if (ubifs_flags & UBIFS_SYNC_FL)
  91                 ioctl_flags |= FS_SYNC_FL;
  92         if (ubifs_flags & UBIFS_APPEND_FL)
  93                 ioctl_flags |= FS_APPEND_FL;
  94         if (ubifs_flags & UBIFS_IMMUTABLE_FL)
  95                 ioctl_flags |= FS_IMMUTABLE_FL;
  96         if (ubifs_flags & UBIFS_DIRSYNC_FL)
  97                 ioctl_flags |= FS_DIRSYNC_FL;
  98
  99         return ioctl_flags;
 100 }
 101
 102 static int setflags(struct inode *inode, int flags)
 103 {
 104         int oldflags, err, release;
 105         struct ubifs_inode *ui = ubifs_inode(inode);
 106         struct ubifs_info *c = inode->i_sb->s_fs_info;
 107         struct ubifs_budget_req req = { .dirtied_ino = 1,
 108                                         .dirtied_ino_d = ui->data_len };
 109
 110         err = ubifs_budget_space(c, &req);
 111         if (err)
 112                 return err;
 113
 114         /*
 115          * The IMMUTABLE and APPEND_ONLY flags can only be changed by
 116          * the relevant capability.
 117          */
 118         mutex_lock(&ui->ui_mutex);
 119         oldflags = ubifs2ioctl(ui->flags);
 120         if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
 121                 if (!capable(CAP_LINUX_IMMUTABLE)) {
 122                         err = -EPERM;
 123                         goto out_unlock;
 124                 }
 125         }
 126
 127         ui->flags = ioctl2ubifs(flags);
 128         ubifs_set_inode_flags(inode);
 129         inode->i_ctime = ubifs_current_time(inode);
 130         release = ui->dirty;
 131         mark_inode_dirty_sync(inode);
 132         mutex_unlock(&ui->ui_mutex);
 133
 134         if (release)
 135                 ubifs_release_budget(c, &req);
 136         if (IS_SYNC(inode))
 137                 err = write_inode_now(inode, 1);
 138         return err;
 139
 140 out_unlock:
 141         ubifs_err("can't modify inode %lu attributes", inode->i_ino);
 142         mutex_unlock(&ui->ui_mutex);
 143         ubifs_release_budget(c, &req);
 144         return err;
 145 }
 146
 147 long ubifs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 148 {
 149         int flags, err;
 150         struct inode *inode = file_inode(file);
 151
 152         switch (cmd) {
 153         case FS_IOC_GETFLAGS:
 154                 flags = ubifs2ioctl(ubifs_inode(inode)->flags);
 155
 156                 dbg_gen("get flags: %#x, i_flags %#x", flags, inode->i_flags);
 157                 return put_user(flags, (int __user *) arg);
 158
 159         case FS_IOC_SETFLAGS: {
 160                 if (IS_RDONLY(inode))
 161                         return -EROFS;
 162
 163                 if (!inode_owner_or_capable(inode))
 164                         return -EACCES;
 165
 166                 if (get_user(flags, (int __user *) arg))
 167                         return -EFAULT;
 168
 169                 if (!S_ISDIR(inode->i_mode))
 170                         flags &= ~FS_DIRSYNC_FL;
 171
 172                 /*
 173                  * Make sure the file-system is read-write and make sure it
 174                  * will not become read-only while we are changing the flags.
 175                  */
 176                 err = mnt_want_write_file(file);
 177                 if (err)
 178                         return err;
 179                 dbg_gen("set flags: %#x, i_flags %#x", flags, inode->i_flags);
 180                 err = setflags(inode, flags);
 181                 mnt_drop_write_file(file);
 182                 return err;
 183         }
 184
 185         default:
 186                 return -ENOTTY;
 187         }
 188 }
 189
 190 #ifdef CONFIG_COMPAT
 191 long ubifs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 192 {
 193         switch (cmd) {
 194         case FS_IOC32_GETFLAGS:
 195                 cmd = FS_IOC_GETFLAGS;
 196                 break;
 197         case FS_IOC32_SETFLAGS:
 198                 cmd = FS_IOC_SETFLAGS;
 199                 break;
 200         default:
 201                 return -ENOIOCTLCMD;
 202         }
 203         return ubifs_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
 204 }
 205 #endif