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  */
  27 static 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
  60 static 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
  74 static 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
  82 static 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
 132 out_unlock_inode:
 133         inode_unlock(inode);
 134 out_drop_write:
 135         mnt_drop_write_file(file);
 136 out:
 137         return err;
 138 }
 139
 140 long 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 }