/usr/src/virtualbox-guest-4.1.42/vboxsf/vfsmod.c is in virtualbox-guest-dkms 4.1.42-dfsg-1+deb7u1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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*
* vboxsf -- VirtualBox Guest Additions for Linux:
* Virtual File System for VirtualBox Shared Folders
*
* Module initialization/finalization
* File system registration/deregistration
* Superblock reading
* Few utility functions
*/
/*
* Copyright (C) 2006-2010 Oracle Corporation
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*/
/**
* @note Anyone wishing to make changes here might wish to take a look at
* http://www.atnf.csiro.au/people/rgooch/linux/vfs.txt
* which seems to be the closest there is to official documentation on
* writing filesystem drivers for Linux.
*/
#include "vfsmod.h"
MODULE_DESCRIPTION(VBOX_PRODUCT " VFS Module for Host File System Access");
MODULE_AUTHOR(VBOX_VENDOR);
MODULE_LICENSE("GPL");
#ifdef MODULE_VERSION
MODULE_VERSION(VBOX_VERSION_STRING " (interface " RT_XSTR(VMMDEV_VERSION) ")");
#endif
/* globals */
VBSFCLIENT client_handle;
/* forward declarations */
static struct super_operations sf_super_ops;
/* allocate global info, try to map host share */
static int sf_glob_alloc(struct vbsf_mount_info_new *info, struct sf_glob_info **sf_gp)
{
int err, rc;
SHFLSTRING *str_name;
size_t name_len, str_len;
struct sf_glob_info *sf_g;
TRACE();
sf_g = kmalloc(sizeof(*sf_g), GFP_KERNEL);
if (!sf_g)
{
err = -ENOMEM;
LogRelFunc(("could not allocate memory for global info\n"));
goto fail0;
}
RT_ZERO(*sf_g);
if ( info->nullchar != '\0'
|| info->signature[0] != VBSF_MOUNT_SIGNATURE_BYTE_0
|| info->signature[1] != VBSF_MOUNT_SIGNATURE_BYTE_1
|| info->signature[2] != VBSF_MOUNT_SIGNATURE_BYTE_2)
{
/* An old version of mount.vboxsf made the syscall. Translate the
* old parameters to the new structure. */
struct vbsf_mount_info_old *info_old = (struct vbsf_mount_info_old *)info;
static struct vbsf_mount_info_new info_compat;
info = &info_compat;
memset(info, 0, sizeof(*info));
memcpy(&info->name, &info_old->name, MAX_HOST_NAME);
memcpy(&info->nls_name, &info_old->nls_name, MAX_NLS_NAME);
info->length = offsetof(struct vbsf_mount_info_new, dmode);
info->uid = info_old->uid;
info->gid = info_old->gid;
info->ttl = info_old->ttl;
}
info->name[sizeof(info->name) - 1] = 0;
info->nls_name[sizeof(info->nls_name) - 1] = 0;
name_len = strlen(info->name);
if (name_len > 0xfffe)
{
err = -ENAMETOOLONG;
LogFunc(("map name too big\n"));
goto fail1;
}
str_len = offsetof(SHFLSTRING, String.utf8) + name_len + 1;
str_name = kmalloc(str_len, GFP_KERNEL);
if (!str_name)
{
err = -ENOMEM;
LogRelFunc(("could not allocate memory for host name\n"));
goto fail1;
}
str_name->u16Length = name_len;
str_name->u16Size = name_len + 1;
memcpy(str_name->String.utf8, info->name, name_len + 1);
#define _IS_UTF8(_str) \
(strcmp(_str, "utf8") == 0)
#define _IS_EMPTY(_str) \
(strcmp(_str, "") == 0)
/* Check if NLS charset is valid and not points to UTF8 table */
if (info->nls_name[0])
{
if (_IS_UTF8(info->nls_name))
sf_g->nls = NULL;
else
{
sf_g->nls = load_nls(info->nls_name);
if (!sf_g->nls)
{
err = -EINVAL;
LogFunc(("failed to load nls %s\n", info->nls_name));
goto fail1;
}
}
}
else
{
#ifdef CONFIG_NLS_DEFAULT
/* If no NLS charset specified, try to load the default
* one if it's not points to UTF8. */
if (!_IS_UTF8(CONFIG_NLS_DEFAULT) && !_IS_EMPTY(CONFIG_NLS_DEFAULT))
sf_g->nls = load_nls_default();
else
sf_g->nls = NULL;
#else
sf_g->nls = NULL;
#endif
#undef _IS_UTF8
#undef _IS_EMPTY
}
rc = vboxCallMapFolder(&client_handle, str_name, &sf_g->map);
kfree(str_name);
if (RT_FAILURE(rc))
{
err = -EPROTO;
LogFunc(("vboxCallMapFolder failed rc=%d\n", rc));
goto fail2;
}
sf_g->ttl = info->ttl;
sf_g->uid = info->uid;
sf_g->gid = info->gid;
if ((unsigned)info->length >= sizeof(struct vbsf_mount_info_new))
{
/* new fields */
sf_g->dmode = info->dmode;
sf_g->fmode = info->fmode;
sf_g->dmask = info->dmask;
sf_g->fmask = info->fmask;
}
else
{
sf_g->dmode = ~0;
sf_g->fmode = ~0;
}
*sf_gp = sf_g;
return 0;
fail2:
if (sf_g->nls)
unload_nls(sf_g->nls);
fail1:
kfree(sf_g);
fail0:
return err;
}
/* unmap the share and free global info [sf_g] */
static void
sf_glob_free(struct sf_glob_info *sf_g)
{
int rc;
TRACE();
rc = vboxCallUnmapFolder(&client_handle, &sf_g->map);
if (RT_FAILURE(rc))
LogFunc(("vboxCallUnmapFolder failed rc=%d\n", rc));
if (sf_g->nls)
unload_nls(sf_g->nls);
kfree(sf_g);
}
/**
* This is called (by sf_read_super_[24|26] when vfs mounts the fs and
* wants to read super_block.
*
* calls [sf_glob_alloc] to map the folder and allocate global
* information structure.
*
* initializes [sb], initializes root inode and dentry.
*
* should respect [flags]
*/
static int sf_read_super_aux(struct super_block *sb, void *data, int flags)
{
int err;
struct dentry *droot;
struct inode *iroot;
struct sf_inode_info *sf_i;
struct sf_glob_info *sf_g;
SHFLFSOBJINFO fsinfo;
struct vbsf_mount_info_new *info;
bool fInodePut = true;
TRACE();
if (!data)
{
LogFunc(("no mount info specified\n"));
return -EINVAL;
}
info = data;
if (flags & MS_REMOUNT)
{
LogFunc(("remounting is not supported\n"));
return -ENOSYS;
}
err = sf_glob_alloc(info, &sf_g);
if (err)
goto fail0;
sf_i = kmalloc(sizeof (*sf_i), GFP_KERNEL);
if (!sf_i)
{
err = -ENOMEM;
LogRelFunc(("could not allocate memory for root inode info\n"));
goto fail1;
}
sf_i->handle = SHFL_HANDLE_NIL;
sf_i->path = kmalloc(sizeof(SHFLSTRING) + 1, GFP_KERNEL);
if (!sf_i->path)
{
err = -ENOMEM;
LogRelFunc(("could not allocate memory for root inode path\n"));
goto fail2;
}
sf_i->path->u16Length = 1;
sf_i->path->u16Size = 2;
sf_i->path->String.utf8[0] = '/';
sf_i->path->String.utf8[1] = 0;
sf_i->force_reread = 0;
err = sf_stat(__func__, sf_g, sf_i->path, &fsinfo, 0);
if (err)
{
LogFunc(("could not stat root of share\n"));
goto fail3;
}
sb->s_magic = 0xface;
sb->s_blocksize = 1024;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 4, 3)
/* Required for seek/sendfile.
*
* Must by less than or equal to INT64_MAX despite the fact that the
* declaration of this variable is unsigned long long. See determination
* of 'loff_t max' in fs/read_write.c / do_sendfile(). I don't know the
* correct limit but MAX_LFS_FILESIZE (8TB-1 on 32-bit boxes) takes the
* page cache into account and is the suggested limit. */
# if defined MAX_LFS_FILESIZE
sb->s_maxbytes = MAX_LFS_FILESIZE;
# else
sb->s_maxbytes = 0x7fffffffffffffffULL;
# endif
#endif
sb->s_op = &sf_super_ops;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 4, 25)
iroot = iget_locked(sb, 0);
#else
iroot = iget(sb, 0);
#endif
if (!iroot)
{
err = -ENOMEM; /* XXX */
LogFunc(("could not get root inode\n"));
goto fail3;
}
if (sf_init_backing_dev(sf_g))
{
err = -EINVAL;
LogFunc(("could not init bdi\n"));
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 4, 25)
unlock_new_inode(iroot);
#endif
goto fail4;
}
sf_init_inode(sf_g, iroot, &fsinfo);
SET_INODE_INFO(iroot, sf_i);
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 4, 25)
unlock_new_inode(iroot);
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 4, 0)
droot = d_make_root(iroot);
#else
droot = d_alloc_root(iroot);
#endif
if (!droot)
{
err = -ENOMEM; /* XXX */
LogFunc(("d_alloc_root failed\n"));
#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 4, 0)
fInodePut = false;
#endif
goto fail5;
}
sb->s_root = droot;
SET_GLOB_INFO(sb, sf_g);
return 0;
fail5:
sf_done_backing_dev(sf_g);
fail4:
if (fInodePut)
iput(iroot);
fail3:
kfree(sf_i->path);
fail2:
kfree(sf_i);
fail1:
sf_glob_free(sf_g);
fail0:
return err;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 0)
static struct super_block *
sf_read_super_24(struct super_block *sb, void *data, int flags)
{
int err;
TRACE();
err = sf_read_super_aux(sb, data, flags);
if (err)
return NULL;
return sb;
}
#endif
/* this is called when vfs is about to destroy the [inode]. all
resources associated with this [inode] must be cleared here */
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 36)
static void sf_clear_inode(struct inode *inode)
{
struct sf_inode_info *sf_i;
TRACE();
sf_i = GET_INODE_INFO(inode);
if (!sf_i)
return;
BUG_ON(!sf_i->path);
kfree(sf_i->path);
kfree(sf_i);
SET_INODE_INFO(inode, NULL);
}
#else
static void sf_evict_inode(struct inode *inode)
{
struct sf_inode_info *sf_i;
TRACE();
truncate_inode_pages(&inode->i_data, 0);
# if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 5, 0)
clear_inode(inode);
# else
end_writeback(inode);
# endif
sf_i = GET_INODE_INFO(inode);
if (!sf_i)
return;
BUG_ON(!sf_i->path);
kfree(sf_i->path);
kfree(sf_i);
SET_INODE_INFO(inode, NULL);
}
#endif
/* this is called by vfs when it wants to populate [inode] with data.
the only thing that is known about inode at this point is its index
hence we can't do anything here, and let lookup/whatever with the
job to properly fill then [inode] */
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 25)
static void sf_read_inode(struct inode *inode)
{
}
#endif
/* vfs is done with [sb] (umount called) call [sf_glob_free] to unmap
the folder and free [sf_g] */
static void sf_put_super(struct super_block *sb)
{
struct sf_glob_info *sf_g;
sf_g = GET_GLOB_INFO(sb);
BUG_ON(!sf_g);
sf_done_backing_dev(sf_g);
sf_glob_free(sf_g);
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 18)
static int sf_statfs(struct super_block *sb, STRUCT_STATFS *stat)
{
return sf_get_volume_info(sb, stat);
}
#else
static int sf_statfs(struct dentry *dentry, STRUCT_STATFS *stat)
{
struct super_block *sb = dentry->d_inode->i_sb;
return sf_get_volume_info(sb, stat);
}
#endif
static int sf_remount_fs(struct super_block *sb, int *flags, char *data)
{
TRACE();
return -ENOSYS;
}
static struct super_operations sf_super_ops =
{
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 36)
.clear_inode = sf_clear_inode,
#else
.evict_inode = sf_evict_inode,
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 25)
.read_inode = sf_read_inode,
#endif
.put_super = sf_put_super,
.statfs = sf_statfs,
.remount_fs = sf_remount_fs
};
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 0)
static DECLARE_FSTYPE(vboxsf_fs_type, "vboxsf", sf_read_super_24, 0);
#else
static int
sf_read_super_26(struct super_block *sb, void *data, int flags)
{
int err;
TRACE();
err = sf_read_super_aux(sb, data, flags);
if (err)
printk(KERN_DEBUG "sf_read_super_aux err=%d\n", err);
return err;
}
# if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 18)
static struct super_block *sf_get_sb(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data)
{
TRACE();
return get_sb_nodev(fs_type, flags, data, sf_read_super_26);
}
# elif LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 39)
static int sf_get_sb(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data, struct vfsmount *mnt)
{
TRACE();
return get_sb_nodev(fs_type, flags, data, sf_read_super_26, mnt);
}
# else
static struct dentry *sf_mount(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data)
{
TRACE();
return mount_nodev(fs_type, flags, data, sf_read_super_26);
}
# endif
static struct file_system_type vboxsf_fs_type =
{
.owner = THIS_MODULE,
.name = "vboxsf",
# if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 39)
.get_sb = sf_get_sb,
# else
.mount = sf_mount,
# endif
.kill_sb = kill_anon_super
};
#endif
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 0)
static int follow_symlinks = 0;
module_param(follow_symlinks, int, 0);
MODULE_PARM_DESC(follow_symlinks, "Let host resolve symlinks rather than showing them");
#endif
/* Module initialization/finalization handlers */
static int __init init(void)
{
int rcVBox;
int rcRet = 0;
int err;
TRACE();
if (sizeof(struct vbsf_mount_info_new) > PAGE_SIZE)
{
printk(KERN_ERR
"Mount information structure is too large %lu\n"
"Must be less than or equal to %lu\n",
(unsigned long)sizeof (struct vbsf_mount_info_new),
(unsigned long)PAGE_SIZE);
return -EINVAL;
}
err = register_filesystem(&vboxsf_fs_type);
if (err)
{
LogFunc(("register_filesystem err=%d\n", err));
return err;
}
rcVBox = vboxInit();
if (RT_FAILURE(rcVBox))
{
LogRelFunc(("vboxInit failed, rc=%d\n", rcVBox));
rcRet = -EPROTO;
goto fail0;
}
rcVBox = vboxConnect(&client_handle);
if (RT_FAILURE(rcVBox))
{
LogRelFunc(("vboxConnect failed, rc=%d\n", rcVBox));
rcRet = -EPROTO;
goto fail1;
}
rcVBox = vboxCallSetUtf8(&client_handle);
if (RT_FAILURE(rcVBox))
{
LogRelFunc(("vboxCallSetUtf8 failed, rc=%d\n", rcVBox));
rcRet = -EPROTO;
goto fail2;
}
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 0)
if (!follow_symlinks)
{
rcVBox = vboxCallSetSymlinks(&client_handle);
if (RT_FAILURE(rcVBox))
{
printk(KERN_WARNING
"vboxsf: Host unable to show symlinks, rc=%d\n",
rcVBox);
}
}
#endif
printk(KERN_DEBUG
"vboxsf: Successfully loaded version " VBOX_VERSION_STRING
" (interface " RT_XSTR(VMMDEV_VERSION) ")\n");
return 0;
fail2:
vboxDisconnect(&client_handle);
fail1:
vboxUninit();
fail0:
unregister_filesystem(&vboxsf_fs_type);
return rcRet;
}
static void __exit fini(void)
{
TRACE();
vboxDisconnect(&client_handle);
vboxUninit();
unregister_filesystem(&vboxsf_fs_type);
}
module_init(init);
module_exit(fini);
/* C++ hack */
int __gxx_personality_v0 = 0xdeadbeef;
|