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ntfs-3g/libntfs-3g/reparse.c
Jean-Pierre André da33b0328f Used plugins to process reparse points 
The new "system compression" files used by Windows 10 make use of reparse
points to record the compression parameters, and a specific named data
stream is used to store the compressed data. With this patch, processing
of reparse points can be done by an external plugin only loaded as needed.
Junctions and symlinks, which are also based on reparse points, are now
processed by "internal plugins".
2016-04-06 09:10:35 +02:00

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/**
* reparse.c - Processing of reparse points
*
* This module is part of ntfs-3g library
*
* Copyright (c) 2008-2016 Jean-Pierre Andre
*
* This program/include file is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as published
* by the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program/include file is distributed in the hope that it will be
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program (in the main directory of the NTFS-3G
* distribution in the file COPYING); if not, write to the Free Software
* Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_SETXATTR
#include <sys/xattr.h>
#endif
#ifdef HAVE_SYS_SYSMACROS_H
#include <sys/sysmacros.h>
#endif
#include "compat.h"
#include "types.h"
#include "debug.h"
#include "layout.h"
#include "attrib.h"
#include "inode.h"
#include "dir.h"
#include "volume.h"
#include "mft.h"
#include "index.h"
#include "lcnalloc.h"
#include "logging.h"
#include "misc.h"
#include "reparse.h"
struct MOUNT_POINT_REPARSE_DATA { /* reparse data for junctions */
le16 subst_name_offset;
le16 subst_name_length;
le16 print_name_offset;
le16 print_name_length;
char path_buffer[0]; /* above data assume this is char array */
} ;
struct SYMLINK_REPARSE_DATA { /* reparse data for symlinks */
le16 subst_name_offset;
le16 subst_name_length;
le16 print_name_offset;
le16 print_name_length;
le32 flags; /* 1 for full target, otherwise 0 */
char path_buffer[0]; /* above data assume this is char array */
} ;
struct REPARSE_INDEX { /* index entry in $Extend/$Reparse */
INDEX_ENTRY_HEADER header;
REPARSE_INDEX_KEY key;
le32 filling;
} ;
static const ntfschar dir_junction_head[] = {
const_cpu_to_le16('\\'),
const_cpu_to_le16('?'),
const_cpu_to_le16('?'),
const_cpu_to_le16('\\')
} ;
static const ntfschar vol_junction_head[] = {
const_cpu_to_le16('\\'),
const_cpu_to_le16('?'),
const_cpu_to_le16('?'),
const_cpu_to_le16('\\'),
const_cpu_to_le16('V'),
const_cpu_to_le16('o'),
const_cpu_to_le16('l'),
const_cpu_to_le16('u'),
const_cpu_to_le16('m'),
const_cpu_to_le16('e'),
const_cpu_to_le16('{'),
} ;
static ntfschar reparse_index_name[] = { const_cpu_to_le16('$'),
const_cpu_to_le16('R') };
static const char mappingdir[] = ".NTFS-3G/";
/*
* Fix a file name with doubtful case in some directory index
* and return the name with the casing used in directory.
*
* Should only be used to translate paths stored with case insensitivity
* (such as directory junctions) when no case conflict is expected.
* If there some ambiguity, the name which collates first is returned.
*
* The name is converted to upper case and searched the usual way.
* The collation rules for file names are such that we should get the
* first candidate if any.
*/
static u64 ntfs_fix_file_name(ntfs_inode *dir_ni, ntfschar *uname,
int uname_len)
{
ntfs_volume *vol = dir_ni->vol;
ntfs_index_context *icx;
u64 mref;
le64 lemref;
int lkup;
int olderrno;
int i;
u32 cpuchar;
INDEX_ENTRY *entry;
FILE_NAME_ATTR *found;
struct {
FILE_NAME_ATTR attr;
ntfschar file_name[NTFS_MAX_NAME_LEN + 1];
} find;
mref = (u64)-1; /* default return (not found) */
icx = ntfs_index_ctx_get(dir_ni, NTFS_INDEX_I30, 4);
if (icx) {
if (uname_len > NTFS_MAX_NAME_LEN)
uname_len = NTFS_MAX_NAME_LEN;
find.attr.file_name_length = uname_len;
for (i=0; i<uname_len; i++) {
cpuchar = le16_to_cpu(uname[i]);
/*
* We need upper or lower value, whichever is smaller,
* but we can only convert to upper case, so we
* will fail when searching for an upper case char
* whose lower case is smaller (such as umlauted Y)
*/
if ((cpuchar < vol->upcase_len)
&& (le16_to_cpu(vol->upcase[cpuchar]) < cpuchar))
find.attr.file_name[i] = vol->upcase[cpuchar];
else
find.attr.file_name[i] = uname[i];
}
olderrno = errno;
lkup = ntfs_index_lookup((char*)&find, uname_len, icx);
if (errno == ENOENT)
errno = olderrno;
/*
* We generally only get the first matching candidate,
* so we still have to check whether this is a real match
*/
if (icx->entry && (icx->entry->ie_flags & INDEX_ENTRY_END))
/* get next entry if reaching end of block */
entry = ntfs_index_next(icx->entry, icx);
else
entry = icx->entry;
if (entry) {
found = &entry->key.file_name;
if (lkup
&& ntfs_names_are_equal(find.attr.file_name,
find.attr.file_name_length,
found->file_name, found->file_name_length,
IGNORE_CASE,
vol->upcase, vol->upcase_len))
lkup = 0;
if (!lkup) {
/*
* name found :
* fix original name and return inode
*/
lemref = entry->indexed_file;
mref = le64_to_cpu(lemref);
if (NVolCaseSensitive(vol) || !vol->locase) {
for (i=0; i<found->file_name_length; i++)
uname[i] = found->file_name[i];
} else {
for (i=0; i<found->file_name_length; i++)
uname[i] = vol->locase[le16_to_cpu(found->file_name[i])];
}
}
}
ntfs_index_ctx_put(icx);
}
return (mref);
}
/*
* Search for a directory junction or a symbolic link
* along the target path, with target defined as a full absolute path
*
* Returns the path translated to a Linux path
* or NULL if the path is not valid
*/
static char *search_absolute(ntfs_volume *vol, ntfschar *path,
int count, BOOL isdir)
{
ntfs_inode *ni;
u64 inum;
char *target;
int start;
int len;
target = (char*)NULL; /* default return */
ni = ntfs_inode_open(vol, (MFT_REF)FILE_root);
if (ni) {
start = 0;
/*
* Examine and translate the path, until we reach either
* - the end,
* - an unknown item
* - a non-directory
* - another reparse point,
* A reparse point is not dereferenced, it will be
* examined later when the translated path is dereferenced,
* however the final part of the path will not be adjusted
* to correct case.
*/
do {
len = 0;
while (((start + len) < count)
&& (path[start + len] != const_cpu_to_le16('\\')))
len++;
inum = ntfs_fix_file_name(ni, &path[start], len);
ntfs_inode_close(ni);
ni = (ntfs_inode*)NULL;
if (inum != (u64)-1) {
inum = MREF(inum);
ni = ntfs_inode_open(vol, inum);
start += len;
if (start < count)
path[start++] = const_cpu_to_le16('/');
}
} while (ni
&& (ni->mrec->flags & MFT_RECORD_IS_DIRECTORY)
&& !(ni->flags & FILE_ATTR_REPARSE_POINT)
&& (start < count));
if (ni
&& ((ni->mrec->flags & MFT_RECORD_IS_DIRECTORY ? isdir : !isdir)
|| (ni->flags & FILE_ATTR_REPARSE_POINT)))
if (ntfs_ucstombs(path, count, &target, 0) < 0) {
if (target) {
free(target);
target = (char*)NULL;
}
}
if (ni)
ntfs_inode_close(ni);
}
return (target);
}
/*
* Search for a symbolic link along the target path,
* with the target defined as a relative path
*
* Note : the path used to access the current inode, may be
* different from the one implied in the target definition,
* when an inode has names in several directories.
*
* Returns the path translated to a Linux path
* or NULL if the path is not valid
*/
static char *search_relative(ntfs_inode *ni, ntfschar *path, int count)
{
char *target = (char*)NULL;
ntfs_inode *curni;
ntfs_inode *newni;
u64 inum;
int pos;
int lth;
BOOL ok;
BOOL morelinks;
int max = 32; /* safety */
pos = 0;
ok = TRUE;
morelinks = FALSE;
curni = ntfs_dir_parent_inode(ni);
/*
* Examine and translate the path, until we reach either
* - the end,
* - an unknown item
* - a non-directory
* - another reparse point,
* A reparse point is not dereferenced, it will be
* examined later when the translated path is dereferenced,
* however the final part of the path will not be adjusted
* to correct case.
*/
while (curni && ok && !morelinks && (pos < (count - 1)) && --max) {
if ((count >= (pos + 2))
&& (path[pos] == const_cpu_to_le16('.'))
&& (path[pos+1] == const_cpu_to_le16('\\'))) {
path[pos+1] = const_cpu_to_le16('/');
pos += 2;
} else {
if ((count >= (pos + 3))
&& (path[pos] == const_cpu_to_le16('.'))
&&(path[pos+1] == const_cpu_to_le16('.'))
&& (path[pos+2] == const_cpu_to_le16('\\'))) {
path[pos+2] = const_cpu_to_le16('/');
pos += 3;
newni = ntfs_dir_parent_inode(curni);
if (curni != ni)
ntfs_inode_close(curni);
curni = newni;
if (!curni)
ok = FALSE;
} else {
lth = 0;
while (((pos + lth) < count)
&& (path[pos + lth] != const_cpu_to_le16('\\')))
lth++;
if (lth > 0)
inum = ntfs_fix_file_name(curni,&path[pos],lth);
else
inum = (u64)-1;
if (!lth
|| ((curni != ni)
&& ntfs_inode_close(curni))
|| (inum == (u64)-1))
ok = FALSE;
else {
curni = ntfs_inode_open(ni->vol, MREF(inum));
if (!curni)
ok = FALSE;
else {
if (curni->flags & FILE_ATTR_REPARSE_POINT)
morelinks = TRUE;
if (ok && ((pos + lth) < count)) {
path[pos + lth] = const_cpu_to_le16('/');
pos += lth + 1;
if (morelinks
&& ntfs_inode_close(curni))
ok = FALSE;
} else {
pos += lth;
if (!morelinks
&& (ni->mrec->flags ^ curni->mrec->flags)
& MFT_RECORD_IS_DIRECTORY)
ok = FALSE;
if (ntfs_inode_close(curni))
ok = FALSE;
}
}
}
}
}
}
if (ok && (ntfs_ucstombs(path, count, &target, 0) < 0)) {
free(target); // needed ?
target = (char*)NULL;
}
return (target);
}
/*
* Check whether a drive letter has been defined in .NTFS-3G
*
* Returns 1 if found,
* 0 if not found,
* -1 if there was an error (described by errno)
*/
static int ntfs_drive_letter(ntfs_volume *vol, ntfschar letter)
{
char defines[NTFS_MAX_NAME_LEN + 5];
char *drive;
int ret;
int sz;
int olderrno;
ntfs_inode *ni;
ret = -1;
drive = (char*)NULL;
sz = ntfs_ucstombs(&letter, 1, &drive, 0);
if (sz > 0) {
strcpy(defines,mappingdir);
if ((*drive >= 'a') && (*drive <= 'z'))
*drive += 'A' - 'a';
strcat(defines,drive);
strcat(defines,":");
olderrno = errno;
ni = ntfs_pathname_to_inode(vol, NULL, defines);
if (ni && !ntfs_inode_close(ni))
ret = 1;
else
if (errno == ENOENT) {
ret = 0;
/* avoid errno pollution */
errno = olderrno;
}
}
if (drive)
free(drive);
return (ret);
}
/*
* Do some sanity checks on reparse data
*
* Microsoft reparse points have an 8-byte header whereas
* non-Microsoft reparse points have a 24-byte header. In each case,
* 'reparse_data_length' must equal the number of non-header bytes.
*
* If the reparse data looks like a junction point or symbolic
* link, more checks can be done.
*
*/
static BOOL valid_reparse_data(ntfs_inode *ni,
const REPARSE_POINT *reparse_attr, size_t size)
{
BOOL ok;
unsigned int offs;
unsigned int lth;
const struct MOUNT_POINT_REPARSE_DATA *mount_point_data;
const struct SYMLINK_REPARSE_DATA *symlink_data;
ok = ni && reparse_attr
&& (size >= sizeof(REPARSE_POINT))
&& (reparse_attr->reparse_tag != IO_REPARSE_TAG_RESERVED_ZERO)
&& (((size_t)le16_to_cpu(reparse_attr->reparse_data_length)
+ sizeof(REPARSE_POINT)
+ ((reparse_attr->reparse_tag &
IO_REPARSE_TAG_IS_MICROSOFT) ? 0 : sizeof(GUID))) == size);
if (ok) {
switch (reparse_attr->reparse_tag) {
case IO_REPARSE_TAG_MOUNT_POINT :
mount_point_data = (const struct MOUNT_POINT_REPARSE_DATA*)
reparse_attr->reparse_data;
offs = le16_to_cpu(mount_point_data->subst_name_offset);
lth = le16_to_cpu(mount_point_data->subst_name_length);
/* consistency checks */
if (!(ni->mrec->flags & MFT_RECORD_IS_DIRECTORY)
|| ((size_t)((sizeof(REPARSE_POINT)
+ sizeof(struct MOUNT_POINT_REPARSE_DATA)
+ offs + lth)) > size))
ok = FALSE;
break;
case IO_REPARSE_TAG_SYMLINK :
symlink_data = (const struct SYMLINK_REPARSE_DATA*)
reparse_attr->reparse_data;
offs = le16_to_cpu(symlink_data->subst_name_offset);
lth = le16_to_cpu(symlink_data->subst_name_length);
if ((size_t)((sizeof(REPARSE_POINT)
+ sizeof(struct SYMLINK_REPARSE_DATA)
+ offs + lth)) > size)
ok = FALSE;
break;
default :
break;
}
}
if (!ok)
errno = EINVAL;
return (ok);
}
/*
* Check and translate the target of a junction point or
* a full absolute symbolic link.
*
* A full target definition begins with "\??\" or "\\?\"
*
* The fully defined target is redefined as a relative link,
* - either to the target if found on the same device.
* - or into the /.NTFS-3G directory for the user to define
* In the first situation, the target is translated to case-sensitive path.
*
* returns the target converted to a relative symlink
* or NULL if there were some problem, as described by errno
*/
static char *ntfs_get_fulllink(ntfs_volume *vol, ntfschar *junction,
int count, const char *mnt_point, BOOL isdir)
{
char *target;
char *fulltarget;
int sz;
char *q;
enum { DIR_JUNCTION, VOL_JUNCTION, NO_JUNCTION } kind;
target = (char*)NULL;
fulltarget = (char*)NULL;
/*
* For a valid directory junction we want \??\x:\
* where \ is an individual char and x a non-null char
*/
if ((count >= 7)
&& !memcmp(junction,dir_junction_head,8)
&& junction[4]
&& (junction[5] == const_cpu_to_le16(':'))
&& (junction[6] == const_cpu_to_le16('\\')))
kind = DIR_JUNCTION;
else
/*
* For a valid volume junction we want \\?\Volume{
* and a final \ (where \ is an individual char)
*/
if ((count >= 12)
&& !memcmp(junction,vol_junction_head,22)
&& (junction[count-1] == const_cpu_to_le16('\\')))
kind = VOL_JUNCTION;
else
kind = NO_JUNCTION;
/*
* Directory junction with an explicit path and
* no specific definition for the drive letter :
* try to interpret as a target on the same volume
*/
if ((kind == DIR_JUNCTION)
&& (count >= 7)
&& junction[7]
&& !ntfs_drive_letter(vol, junction[4])) {
target = search_absolute(vol,&junction[7],count - 7, isdir);
if (target) {
fulltarget = (char*)ntfs_malloc(strlen(mnt_point)
+ strlen(target) + 2);
if (fulltarget) {
strcpy(fulltarget,mnt_point);
strcat(fulltarget,"/");
strcat(fulltarget,target);
}
free(target);
}
}
/*
* Volume junctions or directory junctions with
* target not found on current volume :
* link to /.NTFS-3G/target which the user can
* define as a symbolic link to the real target
*/
if (((kind == DIR_JUNCTION) && !fulltarget)
|| (kind == VOL_JUNCTION)) {
sz = ntfs_ucstombs(&junction[4],
(kind == VOL_JUNCTION ? count - 5 : count - 4),
&target, 0);
if ((sz > 0) && target) {
/* reverse slashes */
for (q=target; *q; q++)
if (*q == '\\')
*q = '/';
/* force uppercase drive letter */
if ((target[1] == ':')
&& (target[0] >= 'a')
&& (target[0] <= 'z'))
target[0] += 'A' - 'a';
fulltarget = (char*)ntfs_malloc(strlen(mnt_point)
+ sizeof(mappingdir) + strlen(target) + 1);
if (fulltarget) {
strcpy(fulltarget,mnt_point);
strcat(fulltarget,"/");
strcat(fulltarget,mappingdir);
strcat(fulltarget,target);
}
}
if (target)
free(target);
}
return (fulltarget);
}
/*
* Check and translate the target of an absolute symbolic link.
*
* An absolute target definition begins with "\" or "x:\"
*
* The absolute target is redefined as a relative link,
* - either to the target if found on the same device.
* - or into the /.NTFS-3G directory for the user to define
* In the first situation, the target is translated to case-sensitive path.
*
* returns the target converted to a relative symlink
* or NULL if there were some problem, as described by errno
*/
static char *ntfs_get_abslink(ntfs_volume *vol, ntfschar *junction,
int count, const char *mnt_point, BOOL isdir)
{
char *target;
char *fulltarget;
int sz;
char *q;
enum { FULL_PATH, ABS_PATH, REJECTED_PATH } kind;
target = (char*)NULL;
fulltarget = (char*)NULL;
/*
* For a full valid path we want x:\
* where \ is an individual char and x a non-null char
*/
if ((count >= 3)
&& junction[0]
&& (junction[1] == const_cpu_to_le16(':'))
&& (junction[2] == const_cpu_to_le16('\\')))
kind = FULL_PATH;
else
/*
* For an absolute path we want an initial \
*/
if ((count >= 0)
&& (junction[0] == const_cpu_to_le16('\\')))
kind = ABS_PATH;
else
kind = REJECTED_PATH;
/*
* Full path, with a drive letter and
* no specific definition for the drive letter :
* try to interpret as a target on the same volume.
* Do the same for an abs path with no drive letter.
*/
if (((kind == FULL_PATH)
&& (count >= 3)
&& junction[3]
&& !ntfs_drive_letter(vol, junction[0]))
|| (kind == ABS_PATH)) {
if (kind == ABS_PATH)
target = search_absolute(vol, &junction[1],
count - 1, isdir);
else
target = search_absolute(vol, &junction[3],
count - 3, isdir);
if (target) {
fulltarget = (char*)ntfs_malloc(strlen(mnt_point)
+ strlen(target) + 2);
if (fulltarget) {
strcpy(fulltarget,mnt_point);
strcat(fulltarget,"/");
strcat(fulltarget,target);
}
free(target);
}
}
/*
* full path with target not found on current volume :
* link to /.NTFS-3G/target which the user can
* define as a symbolic link to the real target
*/
if ((kind == FULL_PATH) && !fulltarget) {
sz = ntfs_ucstombs(&junction[0],
count,&target, 0);
if ((sz > 0) && target) {
/* reverse slashes */
for (q=target; *q; q++)
if (*q == '\\')
*q = '/';
/* force uppercase drive letter */
if ((target[1] == ':')
&& (target[0] >= 'a')
&& (target[0] <= 'z'))
target[0] += 'A' - 'a';
fulltarget = (char*)ntfs_malloc(strlen(mnt_point)
+ sizeof(mappingdir) + strlen(target) + 1);
if (fulltarget) {
strcpy(fulltarget,mnt_point);
strcat(fulltarget,"/");
strcat(fulltarget,mappingdir);
strcat(fulltarget,target);
}
}
if (target)
free(target);
}
return (fulltarget);
}
/*
* Check and translate the target of a relative symbolic link.
*
* A relative target definition does not begin with "\"
*
* The original definition of relative target is kept, it is just
* translated to a case-sensitive path.
*
* returns the target converted to a relative symlink
* or NULL if there were some problem, as described by errno
*/
static char *ntfs_get_rellink(ntfs_inode *ni, ntfschar *junction, int count)
{
char *target;
target = search_relative(ni,junction,count);
return (target);
}
/*
* Get the target for a junction point or symbolic link
* Should only be called for files or directories with reparse data
*
* returns the target converted to a relative path, or NULL
* if some error occurred, as described by errno
* errno is EOPNOTSUPP if the reparse point is not a valid
* symbolic link or directory junction
*/
char *ntfs_make_symlink(ntfs_inode *ni, const char *mnt_point,
int *pattr_size)
{
s64 attr_size = 0;
char *target;
unsigned int offs;
unsigned int lth;
ntfs_volume *vol;
REPARSE_POINT *reparse_attr;
struct MOUNT_POINT_REPARSE_DATA *mount_point_data;
struct SYMLINK_REPARSE_DATA *symlink_data;
enum { FULL_TARGET, ABS_TARGET, REL_TARGET } kind;
ntfschar *p;
BOOL bad;
BOOL isdir;
target = (char*)NULL;
bad = TRUE;
isdir = (ni->mrec->flags & MFT_RECORD_IS_DIRECTORY)
!= const_cpu_to_le16(0);
vol = ni->vol;
reparse_attr = (REPARSE_POINT*)ntfs_attr_readall(ni,
AT_REPARSE_POINT,(ntfschar*)NULL, 0, &attr_size);
if (reparse_attr && attr_size
&& valid_reparse_data(ni, reparse_attr, attr_size)) {
switch (reparse_attr->reparse_tag) {
case IO_REPARSE_TAG_MOUNT_POINT :
mount_point_data = (struct MOUNT_POINT_REPARSE_DATA*)
reparse_attr->reparse_data;
offs = le16_to_cpu(mount_point_data->subst_name_offset);
lth = le16_to_cpu(mount_point_data->subst_name_length);
/* reparse data consistency has been checked */
target = ntfs_get_fulllink(vol,
(ntfschar*)&mount_point_data->path_buffer[offs],
lth/2, mnt_point, isdir);
if (target)
bad = FALSE;
break;
case IO_REPARSE_TAG_SYMLINK :
symlink_data = (struct SYMLINK_REPARSE_DATA*)
reparse_attr->reparse_data;
offs = le16_to_cpu(symlink_data->subst_name_offset);
lth = le16_to_cpu(symlink_data->subst_name_length);
p = (ntfschar*)&symlink_data->path_buffer[offs];
/*
* Predetermine the kind of target,
* the called function has to make a full check
*/
if (*p++ == const_cpu_to_le16('\\')) {
if ((*p == const_cpu_to_le16('?'))
|| (*p == const_cpu_to_le16('\\')))
kind = FULL_TARGET;
else
kind = ABS_TARGET;
} else
if (*p == const_cpu_to_le16(':'))
kind = ABS_TARGET;
else
kind = REL_TARGET;
p--;
/* reparse data consistency has been checked */
switch (kind) {
case FULL_TARGET :
if (!(symlink_data->flags
& const_cpu_to_le32(1))) {
target = ntfs_get_fulllink(vol,
p, lth/2,
mnt_point, isdir);
if (target)
bad = FALSE;
}
break;
case ABS_TARGET :
if (symlink_data->flags
& const_cpu_to_le32(1)) {
target = ntfs_get_abslink(vol,
p, lth/2,
mnt_point, isdir);
if (target)
bad = FALSE;
}
break;
case REL_TARGET :
if (symlink_data->flags
& const_cpu_to_le32(1)) {
target = ntfs_get_rellink(ni,
p, lth/2);
if (target)
bad = FALSE;
}
break;
}
break;
}
free(reparse_attr);
}
*pattr_size = attr_size;
if (bad)
errno = EOPNOTSUPP;
return (target);
}
/*
* Check whether a reparse point looks like a junction point
* or a symbolic link.
* Should only be called for files or directories with reparse data
*
* The validity of the target is not checked.
*/
BOOL ntfs_possible_symlink(ntfs_inode *ni)
{
s64 attr_size = 0;
REPARSE_POINT *reparse_attr;
BOOL possible;
possible = FALSE;
reparse_attr = (REPARSE_POINT*)ntfs_attr_readall(ni,
AT_REPARSE_POINT,(ntfschar*)NULL, 0, &attr_size);
if (reparse_attr && attr_size) {
switch (reparse_attr->reparse_tag) {
case IO_REPARSE_TAG_MOUNT_POINT :
case IO_REPARSE_TAG_SYMLINK :
possible = TRUE;
default : ;
}
free(reparse_attr);
}
return (possible);
}
#ifdef HAVE_SETXATTR /* extended attributes interface required */
/*
* Set the index for new reparse data
*
* Returns 0 if success
* -1 if failure, explained by errno
*/
static int set_reparse_index(ntfs_inode *ni, ntfs_index_context *xr,
le32 reparse_tag)
{
struct REPARSE_INDEX indx;
u64 file_id_cpu;
le64 file_id;
le16 seqn;
seqn = ni->mrec->sequence_number;
file_id_cpu = MK_MREF(ni->mft_no,le16_to_cpu(seqn));
file_id = cpu_to_le64(file_id_cpu);
indx.header.data_offset = const_cpu_to_le16(
sizeof(INDEX_ENTRY_HEADER)
+ sizeof(REPARSE_INDEX_KEY));
indx.header.data_length = const_cpu_to_le16(0);
indx.header.reservedV = const_cpu_to_le32(0);
indx.header.length = const_cpu_to_le16(
sizeof(struct REPARSE_INDEX));
indx.header.key_length = const_cpu_to_le16(
sizeof(REPARSE_INDEX_KEY));
indx.header.flags = const_cpu_to_le16(0);
indx.header.reserved = const_cpu_to_le16(0);
indx.key.reparse_tag = reparse_tag;
/* danger on processors which require proper alignment ! */
memcpy(&indx.key.file_id, &file_id, 8);
indx.filling = const_cpu_to_le32(0);
ntfs_index_ctx_reinit(xr);
return (ntfs_ie_add(xr,(INDEX_ENTRY*)&indx));
}
#endif /* HAVE_SETXATTR */
/*
* Remove a reparse data index entry if attribute present
*
* Returns the size of existing reparse data
* (the existing reparse tag is returned)
* -1 if failure, explained by errno
*/
static int remove_reparse_index(ntfs_attr *na, ntfs_index_context *xr,
le32 *preparse_tag)
{
REPARSE_INDEX_KEY key;
u64 file_id_cpu;
le64 file_id;
s64 size;
le16 seqn;
int ret;
ret = na->data_size;
if (ret) {
/* read the existing reparse_tag */
size = ntfs_attr_pread(na, 0, 4, preparse_tag);
if (size == 4) {
seqn = na->ni->mrec->sequence_number;
file_id_cpu = MK_MREF(na->ni->mft_no,le16_to_cpu(seqn));
file_id = cpu_to_le64(file_id_cpu);
key.reparse_tag = *preparse_tag;
/* danger on processors which require proper alignment ! */
memcpy(&key.file_id, &file_id, 8);
if (!ntfs_index_lookup(&key, sizeof(REPARSE_INDEX_KEY), xr)
&& ntfs_index_rm(xr))
ret = -1;
} else {
ret = -1;
errno = ENODATA;
}
}
return (ret);
}
/*
* Open the $Extend/$Reparse file and its index
*
* Return the index context if opened
* or NULL if an error occurred (errno tells why)
*
* The index has to be freed and inode closed when not needed any more.
*/
static ntfs_index_context *open_reparse_index(ntfs_volume *vol)
{
u64 inum;
ntfs_inode *ni;
ntfs_inode *dir_ni;
ntfs_index_context *xr;
/* do not use path_name_to inode - could reopen root */
dir_ni = ntfs_inode_open(vol, FILE_Extend);
ni = (ntfs_inode*)NULL;
if (dir_ni) {
inum = ntfs_inode_lookup_by_mbsname(dir_ni,"$Reparse");
if (inum != (u64)-1)
ni = ntfs_inode_open(vol, inum);
ntfs_inode_close(dir_ni);
}
if (ni) {
xr = ntfs_index_ctx_get(ni, reparse_index_name, 2);
if (!xr) {
ntfs_inode_close(ni);
}
} else
xr = (ntfs_index_context*)NULL;
return (xr);
}
#ifdef HAVE_SETXATTR /* extended attributes interface required */
/*
* Update the reparse data and index
*
* The reparse data attribute should have been created, and
* an existing index is expected if there is an existing value.
*
* Returns 0 if success
* -1 if failure, explained by errno
* If could not remove the existing index, nothing is done,
* If could not write the new data, no index entry is inserted
* If failed to insert the index, data is removed
*/
static int update_reparse_data(ntfs_inode *ni, ntfs_index_context *xr,
const char *value, size_t size)
{
int res;
int written;
int oldsize;
ntfs_attr *na;
le32 reparse_tag;
res = 0;
na = ntfs_attr_open(ni, AT_REPARSE_POINT, AT_UNNAMED, 0);
if (na) {
/* remove the existing reparse data */
oldsize = remove_reparse_index(na,xr,&reparse_tag);
if (oldsize < 0)
res = -1;
else {
/* resize attribute */
res = ntfs_attr_truncate(na, (s64)size);
/* overwrite value if any */
if (!res && value) {
written = (int)ntfs_attr_pwrite(na,
(s64)0, (s64)size, value);
if (written != (s64)size) {
ntfs_log_error("Failed to update "
"reparse data\n");
errno = EIO;
res = -1;
}
}
if (!res
&& set_reparse_index(ni,xr,
((const REPARSE_POINT*)value)->reparse_tag)
&& (oldsize > 0)) {
/*
* If cannot index, try to remove the reparse
* data and log the error. There will be an
* inconsistency if removal fails.
*/
ntfs_attr_rm(na);
ntfs_log_error("Failed to index reparse data."
" Possible corruption.\n");
}
}
ntfs_attr_close(na);
NInoSetDirty(ni);
} else
res = -1;
return (res);
}
#endif /* HAVE_SETXATTR */
/*
* Delete a reparse index entry
*
* Returns 0 if success
* -1 if failure, explained by errno
*/
int ntfs_delete_reparse_index(ntfs_inode *ni)
{
ntfs_index_context *xr;
ntfs_inode *xrni;
ntfs_attr *na;
le32 reparse_tag;
int res;
res = 0;
na = ntfs_attr_open(ni, AT_REPARSE_POINT, AT_UNNAMED, 0);
if (na) {
/*
* read the existing reparse data (the tag is enough)
* and un-index it
*/
xr = open_reparse_index(ni->vol);
if (xr) {
if (remove_reparse_index(na,xr,&reparse_tag) < 0)
res = -1;
xrni = xr->ni;
ntfs_index_entry_mark_dirty(xr);
NInoSetDirty(xrni);
ntfs_index_ctx_put(xr);
ntfs_inode_close(xrni);
}
ntfs_attr_close(na);
}
return (res);
}
#ifdef HAVE_SETXATTR /* extended attributes interface required */
/*
* Get the ntfs reparse data into an extended attribute
*
* Returns the reparse data size
* and the buffer is updated if it is long enough
*/
int ntfs_get_ntfs_reparse_data(ntfs_inode *ni, char *value, size_t size)
{
REPARSE_POINT *reparse_attr;
s64 attr_size;
attr_size = 0; /* default to no data and no error */
if (ni) {
if (ni->flags & FILE_ATTR_REPARSE_POINT) {
reparse_attr = (REPARSE_POINT*)ntfs_attr_readall(ni,
AT_REPARSE_POINT,(ntfschar*)NULL, 0, &attr_size);
if (reparse_attr) {
if (attr_size <= (s64)size) {
if (value)
memcpy(value,reparse_attr,
attr_size);
else
errno = EINVAL;
}
free(reparse_attr);
}
} else
errno = ENODATA;
}
return (attr_size ? (int)attr_size : -errno);
}
/*
* Set the reparse data from an extended attribute
*
* Warning : the new data is not checked
*
* Returns 0, or -1 if there is a problem
*/
int ntfs_set_ntfs_reparse_data(ntfs_inode *ni,
const char *value, size_t size, int flags)
{
int res;
u8 dummy;
ntfs_inode *xrni;
ntfs_index_context *xr;
res = 0;
/* reparse data is not compatible with EA */
if (ni
&& !ntfs_attr_exist(ni, AT_EA_INFORMATION, AT_UNNAMED, 0)
&& !ntfs_attr_exist(ni, AT_EA, AT_UNNAMED, 0)
&& valid_reparse_data(ni, (const REPARSE_POINT*)value, size)) {
xr = open_reparse_index(ni->vol);
if (xr) {
if (!ntfs_attr_exist(ni,AT_REPARSE_POINT,
AT_UNNAMED,0)) {
if (!(flags & XATTR_REPLACE)) {
/*
* no reparse data attribute : add one,
* apparently, this does not feed the new value in
* Note : NTFS version must be >= 3
*/
if (ni->vol->major_ver >= 3) {
res = ntfs_attr_add(ni,
AT_REPARSE_POINT,
AT_UNNAMED,0,&dummy,
(s64)0);
if (!res) {
ni->flags |=
FILE_ATTR_REPARSE_POINT;
NInoFileNameSetDirty(ni);
}
NInoSetDirty(ni);
} else {
errno = EOPNOTSUPP;
res = -1;
}
} else {
errno = ENODATA;
res = -1;
}
} else {
if (flags & XATTR_CREATE) {
errno = EEXIST;
res = -1;
}
}
if (!res) {
/* update value and index */
res = update_reparse_data(ni,xr,value,size);
}
xrni = xr->ni;
ntfs_index_entry_mark_dirty(xr);
NInoSetDirty(xrni);
ntfs_index_ctx_put(xr);
ntfs_inode_close(xrni);
} else {
res = -1;
}
} else {
errno = EINVAL;
res = -1;
}
return (res ? -1 : 0);
}
/*
* Remove the reparse data
*
* Returns 0, or -1 if there is a problem
*/
int ntfs_remove_ntfs_reparse_data(ntfs_inode *ni)
{
int res;
int olderrno;
ntfs_attr *na;
ntfs_inode *xrni;
ntfs_index_context *xr;
le32 reparse_tag;
res = 0;
if (ni) {
/*
* open and delete the reparse data
*/
na = ntfs_attr_open(ni, AT_REPARSE_POINT,
AT_UNNAMED,0);
if (na) {
/* first remove index (reparse data needed) */
xr = open_reparse_index(ni->vol);
if (xr) {
if (remove_reparse_index(na,xr,
&reparse_tag) < 0) {
res = -1;
} else {
/* now remove attribute */
res = ntfs_attr_rm(na);
if (!res) {
ni->flags &=
~FILE_ATTR_REPARSE_POINT;
NInoFileNameSetDirty(ni);
} else {
/*
* If we could not remove the
* attribute, try to restore the
* index and log the error. There
* will be an inconsistency if
* the reindexing fails.
*/
set_reparse_index(ni, xr,
reparse_tag);
ntfs_log_error(
"Failed to remove reparse data."
" Possible corruption.\n");
}
}
xrni = xr->ni;
ntfs_index_entry_mark_dirty(xr);
NInoSetDirty(xrni);
ntfs_index_ctx_put(xr);
ntfs_inode_close(xrni);
}
olderrno = errno;
ntfs_attr_close(na);
/* avoid errno pollution */
if (errno == ENOENT)
errno = olderrno;
} else {
errno = ENODATA;
res = -1;
}
NInoSetDirty(ni);
} else {
errno = EINVAL;
res = -1;
}
return (res ? -1 : 0);
}
#endif /* HAVE_SETXATTR */
/*
* Get the reparse data into a buffer
*
* Returns the buffer if the reparse data exists and is valid
* NULL otherwise (with errno set according to the cause).
* When a buffer is returned, it has to be freed by caller.
*/
REPARSE_POINT *ntfs_get_reparse_point(ntfs_inode *ni)
{
s64 attr_size = 0;
REPARSE_POINT *reparse_attr;
reparse_attr = (REPARSE_POINT*)NULL;
if (ni) {
reparse_attr = (REPARSE_POINT*)ntfs_attr_readall(ni,
AT_REPARSE_POINT,(ntfschar*)NULL, 0, &attr_size);
if (reparse_attr
&& !valid_reparse_data(ni, reparse_attr, attr_size)) {
free(reparse_attr);
reparse_attr = (REPARSE_POINT*)NULL;
errno = ENOENT;
}
} else
errno = EINVAL;
return (reparse_attr);
}
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