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 int hfsplus_ioctl_getflags(struct file *file, int __user *user_flags)
  61{
  62        struct inode *inode = file_inode(file);
  63        struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
  64        unsigned int flags = 0;
  65
  66        if (inode->i_flags & S_IMMUTABLE)
  67                flags |= FS_IMMUTABLE_FL;
  68        if (inode->i_flags & S_APPEND)
  69                flags |= FS_APPEND_FL;
  70        if (hip->userflags & HFSPLUS_FLG_NODUMP)
  71                flags |= FS_NODUMP_FL;
  72
  73        return put_user(flags, user_flags);
  74}
  75
  76static int hfsplus_ioctl_setflags(struct file *file, int __user *user_flags)
  77{
  78        struct inode *inode = file_inode(file);
  79        struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
  80        unsigned int flags, new_fl = 0;
  81        int err = 0;
  82
  83        err = mnt_want_write_file(file);
  84        if (err)
  85                goto out;
  86
  87        if (!inode_owner_or_capable(inode)) {
  88                err = -EACCES;
  89                goto out_drop_write;
  90        }
  91
  92        if (get_user(flags, user_flags)) {
  93                err = -EFAULT;
  94                goto out_drop_write;
  95        }
  96
  97        inode_lock(inode);
  98
  99        if ((flags & (FS_IMMUTABLE_FL|FS_APPEND_FL)) ||
 100            inode->i_flags & (S_IMMUTABLE|S_APPEND)) {
 101                if (!capable(CAP_LINUX_IMMUTABLE)) {
 102                        err = -EPERM;
 103                        goto out_unlock_inode;
 104                }
 105        }
 106
 107        /* don't silently ignore unsupported ext2 flags */
 108        if (flags & ~(FS_IMMUTABLE_FL|FS_APPEND_FL|FS_NODUMP_FL)) {
 109                err = -EOPNOTSUPP;
 110                goto out_unlock_inode;
 111        }
 112
 113        if (flags & FS_IMMUTABLE_FL)
 114                new_fl |= S_IMMUTABLE;
 115
 116        if (flags & FS_APPEND_FL)
 117                new_fl |= S_APPEND;
 118
 119        inode_set_flags(inode, new_fl, S_IMMUTABLE | S_APPEND);
 120
 121        if (flags & FS_NODUMP_FL)
 122                hip->userflags |= HFSPLUS_FLG_NODUMP;
 123        else
 124                hip->userflags &= ~HFSPLUS_FLG_NODUMP;
 125
 126        inode->i_ctime = current_time(inode);
 127        mark_inode_dirty(inode);
 128
 129out_unlock_inode:
 130        inode_unlock(inode);
 131out_drop_write:
 132        mnt_drop_write_file(file);
 133out:
 134        return err;
 135}
 136
 137long hfsplus_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 138{
 139        void __user *argp = (void __user *)arg;
 140
 141        switch (cmd) {
 142        case HFSPLUS_IOC_EXT2_GETFLAGS:
 143                return hfsplus_ioctl_getflags(file, argp);
 144        case HFSPLUS_IOC_EXT2_SETFLAGS:
 145                return hfsplus_ioctl_setflags(file, argp);
 146        case HFSPLUS_IOC_BLESS:
 147                return hfsplus_ioctl_bless(file, argp);
 148        default:
 149                return -ENOTTY;
 150        }
 151}
 152