LXR linux/fs/hfsplus/ioctl.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  linux/fs/hfsplus/ioctl.c
   4 *
   5 * Copyright (C) 2003
   6 * Ethan Benson <erbenson@alaska.net>
   7 * partially derived from linux/fs/ext2/ioctl.c
   8 * Copyright (C) 1993, 1994, 1995
   9 * Remy Card (card@masi.ibp.fr)
  10 * Laboratoire MASI - Institut Blaise Pascal
  11 * Universite Pierre et Marie Curie (Paris VI)
  12 *
  13 * hfsplus ioctls
  14 */
  15
  16#include <linux/capability.h>
  17#include <linux/fs.h>
  18#include <linux/mount.h>
  19#include <linux/sched.h>
  20#include <linux/uaccess.h>
  21#include "hfsplus_fs.h"
  22
  23/*
  24 * "Blessing" an HFS+ filesystem writes metadata to the superblock informing
  25 * the platform firmware which file to boot from
  26 */
  27static int hfsplus_ioctl_bless(struct file *file, int __user *user_flags)
  28{
  29        struct dentry *dentry = file->f_path.dentry;
  30        struct inode *inode = d_inode(dentry);
  31        struct hfsplus_sb_info *sbi = HFSPLUS_SB(inode->i_sb);
  32        struct hfsplus_vh *vh = sbi->s_vhdr;
  33        struct hfsplus_vh *bvh = sbi->s_backup_vhdr;
  34        u32 cnid = (unsigned long)dentry->d_fsdata;
  35
  36        if (!capable(CAP_SYS_ADMIN))
  37                return -EPERM;
  38
  39        mutex_lock(&sbi->vh_mutex);
  40
  41        /* Directory containing the bootable system */
  42        vh->finder_info[0] = bvh->finder_info[0] =
  43                cpu_to_be32(parent_ino(dentry));
  44
  45        /*
  46         * Bootloader. Just using the inode here breaks in the case of
  47         * hard links - the firmware wants the ID of the hard link file,
  48         * but the inode points at the indirect inode
  49         */
  50        vh->finder_info[1] = bvh->finder_info[1] = cpu_to_be32(cnid);
  51
  52        /* Per spec, the OS X system folder - same as finder_info[0] here */
  53        vh->finder_info[5] = bvh->finder_info[5] =
  54                cpu_to_be32(parent_ino(dentry));
  55
  56        mutex_unlock(&sbi->vh_mutex);
  57        return 0;
  58}
  59
  60static inline unsigned int hfsplus_getflags(struct inode *inode)
  61{
  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        return flags;
  72}
  73
  74static int hfsplus_ioctl_getflags(struct file *file, int __user *user_flags)
  75{
  76        struct inode *inode = file_inode(file);
  77        unsigned int flags = hfsplus_getflags(inode);
  78
  79        return put_user(flags, user_flags);
  80}
  81
  82static int hfsplus_ioctl_setflags(struct file *file, int __user *user_flags)
  83{
  84        struct inode *inode = file_inode(file);
  85        struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
  86        unsigned int flags, new_fl = 0;
  87        unsigned int oldflags = hfsplus_getflags(inode);
  88        int err = 0;
  89
  90        err = mnt_want_write_file(file);
  91        if (err)
  92                goto out;
  93
  94        if (!inode_owner_or_capable(inode)) {
  95                err = -EACCES;
  96                goto out_drop_write;
  97        }
  98
  99        if (get_user(flags, user_flags)) {
 100                err = -EFAULT;
 101                goto out_drop_write;
 102        }
 103
 104        inode_lock(inode);
 105
 106        err = vfs_ioc_setflags_prepare(inode, oldflags, flags);
 107        if (err)
 108                goto out_unlock_inode;
 109
 110        /* don't silently ignore unsupported ext2 flags */
 111        if (flags & ~(FS_IMMUTABLE_FL|FS_APPEND_FL|FS_NODUMP_FL)) {
 112                err = -EOPNOTSUPP;
 113                goto out_unlock_inode;
 114        }
 115
 116        if (flags & FS_IMMUTABLE_FL)
 117                new_fl |= S_IMMUTABLE;
 118
 119        if (flags & FS_APPEND_FL)
 120                new_fl |= S_APPEND;
 121
 122        inode_set_flags(inode, new_fl, S_IMMUTABLE | S_APPEND);
 123
 124        if (flags & FS_NODUMP_FL)
 125                hip->userflags |= HFSPLUS_FLG_NODUMP;
 126        else
 127                hip->userflags &= ~HFSPLUS_FLG_NODUMP;
 128
 129        inode->i_ctime = current_time(inode);
 130        mark_inode_dirty(inode);
 131
 132out_unlock_inode:
 133        inode_unlock(inode);
 134out_drop_write:
 135        mnt_drop_write_file(file);
 136out:
 137        return err;
 138}
 139
 140long hfsplus_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 141{
 142        void __user *argp = (void __user *)arg;
 143
 144        switch (cmd) {
 145        case HFSPLUS_IOC_EXT2_GETFLAGS:
 146                return hfsplus_ioctl_getflags(file, argp);
 147        case HFSPLUS_IOC_EXT2_SETFLAGS:
 148                return hfsplus_ioctl_setflags(file, argp);
 149        case HFSPLUS_IOC_BLESS:
 150                return hfsplus_ioctl_bless(file, argp);
 151        default:
 152                return -ENOTTY;
 153        }
 154}
 155