linux/fs/hfsplus/ioctl.c
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   1/*
   2 *  linux/fs/hfsplus/ioctl.c
   3 *
   4 * Copyright (C) 2003
   5 * Ethan Benson <erbenson@alaska.net>
   6 * partially derived from linux/fs/ext2/ioctl.c
   7 * Copyright (C) 1993, 1994, 1995
   8 * Remy Card (card@masi.ibp.fr)
   9 * Laboratoire MASI - Institut Blaise Pascal
  10 * Universite Pierre et Marie Curie (Paris VI)
  11 *
  12 * hfsplus ioctls
  13 */
  14
  15#include <linux/capability.h>
  16#include <linux/fs.h>
  17#include <linux/mount.h>
  18#include <linux/sched.h>
  19#include <asm/uaccess.h>
  20#include "hfsplus_fs.h"
  21
  22/*
  23 * "Blessing" an HFS+ filesystem writes metadata to the superblock informing
  24 * the platform firmware which file to boot from
  25 */
  26static int hfsplus_ioctl_bless(struct file *file, int __user *user_flags)
  27{
  28        struct dentry *dentry = file->f_path.dentry;
  29        struct inode *inode = dentry->d_inode;
  30        struct hfsplus_sb_info *sbi = HFSPLUS_SB(inode->i_sb);
  31        struct hfsplus_vh *vh = sbi->s_vhdr;
  32        struct hfsplus_vh *bvh = sbi->s_backup_vhdr;
  33        u32 cnid = (unsigned long)dentry->d_fsdata;
  34
  35        if (!capable(CAP_SYS_ADMIN))
  36                return -EPERM;
  37
  38        mutex_lock(&sbi->vh_mutex);
  39
  40        /* Directory containing the bootable system */
  41        vh->finder_info[0] = bvh->finder_info[0] =
  42                cpu_to_be32(parent_ino(dentry));
  43
  44        /*
  45         * Bootloader. Just using the inode here breaks in the case of
  46         * hard links - the firmware wants the ID of the hard link file,
  47         * but the inode points at the indirect inode
  48         */
  49        vh->finder_info[1] = bvh->finder_info[1] = cpu_to_be32(cnid);
  50
  51        /* Per spec, the OS X system folder - same as finder_info[0] here */
  52        vh->finder_info[5] = bvh->finder_info[5] =
  53                cpu_to_be32(parent_ino(dentry));
  54
  55        mutex_unlock(&sbi->vh_mutex);
  56        return 0;
  57}
  58
  59static int hfsplus_ioctl_getflags(struct file *file, int __user *user_flags)
  60{
  61        struct inode *inode = file_inode(file);
  62        struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
  63        unsigned int flags = 0;
  64
  65        if (inode->i_flags & S_IMMUTABLE)
  66                flags |= FS_IMMUTABLE_FL;
  67        if (inode->i_flags & S_APPEND)
  68                flags |= FS_APPEND_FL;
  69        if (hip->userflags & HFSPLUS_FLG_NODUMP)
  70                flags |= FS_NODUMP_FL;
  71
  72        return put_user(flags, user_flags);
  73}
  74
  75static int hfsplus_ioctl_setflags(struct file *file, int __user *user_flags)
  76{
  77        struct inode *inode = file_inode(file);
  78        struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
  79        unsigned int flags;
  80        int err = 0;
  81
  82        err = mnt_want_write_file(file);
  83        if (err)
  84                goto out;
  85
  86        if (!inode_owner_or_capable(inode)) {
  87                err = -EACCES;
  88                goto out_drop_write;
  89        }
  90
  91        if (get_user(flags, user_flags)) {
  92                err = -EFAULT;
  93                goto out_drop_write;
  94        }
  95
  96        mutex_lock(&inode->i_mutex);
  97
  98        if ((flags & (FS_IMMUTABLE_FL|FS_APPEND_FL)) ||
  99            inode->i_flags & (S_IMMUTABLE|S_APPEND)) {
 100                if (!capable(CAP_LINUX_IMMUTABLE)) {
 101                        err = -EPERM;
 102                        goto out_unlock_inode;
 103                }
 104        }
 105
 106        /* don't silently ignore unsupported ext2 flags */
 107        if (flags & ~(FS_IMMUTABLE_FL|FS_APPEND_FL|FS_NODUMP_FL)) {
 108                err = -EOPNOTSUPP;
 109                goto out_unlock_inode;
 110        }
 111
 112        if (flags & FS_IMMUTABLE_FL)
 113                inode->i_flags |= S_IMMUTABLE;
 114        else
 115                inode->i_flags &= ~S_IMMUTABLE;
 116
 117        if (flags & FS_APPEND_FL)
 118                inode->i_flags |= S_APPEND;
 119        else
 120                inode->i_flags &= ~S_APPEND;
 121
 122        if (flags & FS_NODUMP_FL)
 123                hip->userflags |= HFSPLUS_FLG_NODUMP;
 124        else
 125                hip->userflags &= ~HFSPLUS_FLG_NODUMP;
 126
 127        inode->i_ctime = CURRENT_TIME_SEC;
 128        mark_inode_dirty(inode);
 129
 130out_unlock_inode:
 131        mutex_unlock(&inode->i_mutex);
 132out_drop_write:
 133        mnt_drop_write_file(file);
 134out:
 135        return err;
 136}
 137
 138long hfsplus_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 139{
 140        void __user *argp = (void __user *)arg;
 141
 142        switch (cmd) {
 143        case HFSPLUS_IOC_EXT2_GETFLAGS:
 144                return hfsplus_ioctl_getflags(file, argp);
 145        case HFSPLUS_IOC_EXT2_SETFLAGS:
 146                return hfsplus_ioctl_setflags(file, argp);
 147        case HFSPLUS_IOC_BLESS:
 148                return hfsplus_ioctl_bless(file, argp);
 149        default:
 150                return -ENOTTY;
 151        }
 152}
 153
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