samba-mirror/source3/smbd/vfs.c

/*
   Unix SMB/Netbios implementation.
   Version 1.9.
   VFS initialisation and support functions
   Copyright (C) Tim Potter 1999
   Copyright (C) Alexander Bokovoy 2002
   Copyright (C) James Peach 2006
   Copyright (C) Volker Lendecke 2009

   This program 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 3 of the License, or
   (at your option) any later version.

   This program 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.  If not, see <http://www.gnu.org/licenses/>.

   This work was sponsored by Optifacio Software Services, Inc.
*/

#include "includes.h"
#include "system/filesys.h"
#include "smbd/smbd.h"
#include "smbd/globals.h"
#include "../lib/util/memcache.h"
#include "transfer_file.h"
#include "ntioctl.h"
#include "lib/util/tevent_unix.h"
#include "lib/util/tevent_ntstatus.h"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_VFS

static_decl_vfs;

struct vfs_fsp_data {
    struct vfs_fsp_data *next;
    struct vfs_handle_struct *owner;
    void (*destroy)(void *p_data);
    void *_dummy_;
    /* NOTE: This structure contains four pointers so that we can guarantee
     * that the end of the structure is always both 4-byte and 8-byte aligned.
     */
};

struct vfs_init_function_entry {
	char *name;
	struct vfs_init_function_entry *prev, *next;
	const struct vfs_fn_pointers *fns;
};

/****************************************************************************
    maintain the list of available backends
****************************************************************************/

static struct vfs_init_function_entry *vfs_find_backend_entry(const char *name)
{
	struct vfs_init_function_entry *entry = backends;

	DEBUG(10, ("vfs_find_backend_entry called for %s\n", name));

	while(entry) {
		if (strcmp(entry->name, name)==0) return entry;
		entry = entry->next;
	}

	return NULL;
}

NTSTATUS smb_register_vfs(int version, const char *name,
			  const struct vfs_fn_pointers *fns)
{
	struct vfs_init_function_entry *entry = backends;

 	if ((version != SMB_VFS_INTERFACE_VERSION)) {
		DEBUG(0, ("Failed to register vfs module.\n"
		          "The module was compiled against SMB_VFS_INTERFACE_VERSION %d,\n"
		          "current SMB_VFS_INTERFACE_VERSION is %d.\n"
		          "Please recompile against the current Samba Version!\n",  
			  version, SMB_VFS_INTERFACE_VERSION));
		return NT_STATUS_OBJECT_TYPE_MISMATCH;
  	}

	if (!name || !name[0]) {
		DEBUG(0,("smb_register_vfs() called with NULL pointer or empty name!\n"));
		return NT_STATUS_INVALID_PARAMETER;
	}

	if (vfs_find_backend_entry(name)) {
		DEBUG(0,("VFS module %s already loaded!\n", name));
		return NT_STATUS_OBJECT_NAME_COLLISION;
	}

	entry = SMB_XMALLOC_P(struct vfs_init_function_entry);
	entry->name = smb_xstrdup(name);
	entry->fns = fns;

	DLIST_ADD(backends, entry);
	DEBUG(5, ("Successfully added vfs backend '%s'\n", name));
	return NT_STATUS_OK;
}

/****************************************************************************
  initialise default vfs hooks
****************************************************************************/

static void vfs_init_default(connection_struct *conn)
{
	DEBUG(3, ("Initialising default vfs hooks\n"));
	vfs_init_custom(conn, DEFAULT_VFS_MODULE_NAME);
}

/****************************************************************************
  initialise custom vfs hooks
 ****************************************************************************/

bool vfs_init_custom(connection_struct *conn, const char *vfs_object)
{
	char *module_path = NULL;
	char *module_name = NULL;
	char *module_param = NULL, *p;
	vfs_handle_struct *handle;
	const struct vfs_init_function_entry *entry;

	if (!conn||!vfs_object||!vfs_object[0]) {
		DEBUG(0, ("vfs_init_custom() called with NULL pointer or "
			  "empty vfs_object!\n"));
		return False;
	}

	if(!backends) {
		static_init_vfs(NULL);
	}

	DEBUG(3, ("Initialising custom vfs hooks from [%s]\n", vfs_object));

	module_path = smb_xstrdup(vfs_object);

	p = strchr_m(module_path, ':');

	if (p) {
		*p = 0;
		module_param = p+1;
		trim_char(module_param, ' ', ' ');
	}

	trim_char(module_path, ' ', ' ');

	module_name = smb_xstrdup(module_path);

	if ((module_name[0] == '/') &&
	    (strcmp(module_path, DEFAULT_VFS_MODULE_NAME) != 0)) {

		/*
		 * Extract the module name from the path. Just use the base
		 * name of the last path component.
		 */

		SAFE_FREE(module_name);
		module_name = smb_xstrdup(strrchr_m(module_path, '/')+1);

		p = strchr_m(module_name, '.');

		if (p != NULL) {
			*p = '\0';
		}
	}

	/* First, try to load the module with the new module system */
	entry = vfs_find_backend_entry(module_name);
	if (!entry) {
		NTSTATUS status;

		DEBUG(5, ("vfs module [%s] not loaded - trying to load...\n",
			  vfs_object));

		status = smb_load_module("vfs", module_path);
		if (!NT_STATUS_IS_OK(status)) {
			DEBUG(0, ("error probing vfs module '%s': %s\n",
				  module_path, nt_errstr(status)));
			goto fail;
		}

		entry = vfs_find_backend_entry(module_name);
		if (!entry) {
			DEBUG(0,("Can't find a vfs module [%s]\n",vfs_object));
			goto fail;
		}
	}

	DEBUGADD(5,("Successfully loaded vfs module [%s] with the new modules system\n", vfs_object));

	handle = talloc_zero(conn, vfs_handle_struct);
	if (!handle) {
		DEBUG(0,("TALLOC_ZERO() failed!\n"));
		goto fail;
	}
	handle->conn = conn;
	handle->fns = entry->fns;
	if (module_param) {
		handle->param = talloc_strdup(conn, module_param);
	}
	DLIST_ADD(conn->vfs_handles, handle);

	SAFE_FREE(module_path);
	SAFE_FREE(module_name);
	return True;

 fail:
	SAFE_FREE(module_path);
	SAFE_FREE(module_name);
	return False;
}

/*****************************************************************
 Allow VFS modules to extend files_struct with VFS-specific state.
 This will be ok for small numbers of extensions, but might need to
 be refactored if it becomes more widely used.
******************************************************************/

#define EXT_DATA_AREA(e) ((uint8_t *)(e) + sizeof(struct vfs_fsp_data))

void *vfs_add_fsp_extension_notype(vfs_handle_struct *handle,
				   files_struct *fsp, size_t ext_size,
				   void (*destroy_fn)(void *p_data))
{
	struct vfs_fsp_data *ext;
	void * ext_data;

	/* Prevent VFS modules adding multiple extensions. */
	if ((ext_data = vfs_fetch_fsp_extension(handle, fsp))) {
		return ext_data;
	}

	ext = (struct vfs_fsp_data *)TALLOC_ZERO(
		handle->conn, sizeof(struct vfs_fsp_data) + ext_size);
	if (ext == NULL) {
		return NULL;
	}

	ext->owner = handle;
	ext->next = fsp->vfs_extension;
	ext->destroy = destroy_fn;
	fsp->vfs_extension = ext;
	return EXT_DATA_AREA(ext);
}

void vfs_remove_fsp_extension(vfs_handle_struct *handle, files_struct *fsp)
{
	struct vfs_fsp_data *curr;
	struct vfs_fsp_data *prev;

	for (curr = fsp->vfs_extension, prev = NULL;
	     curr;
	     prev = curr, curr = curr->next) {
		if (curr->owner == handle) {
		    if (prev) {
			    prev->next = curr->next;
		    } else {
			    fsp->vfs_extension = curr->next;
		    }
		    if (curr->destroy) {
			    curr->destroy(EXT_DATA_AREA(curr));
		    }
		    TALLOC_FREE(curr);
		    return;
		}
	}
}

void vfs_remove_all_fsp_extensions(files_struct *fsp)
{
	struct vfs_fsp_data *curr;
	struct vfs_fsp_data *next;

	for (curr = fsp->vfs_extension; curr; curr = next) {

		next = curr->next;
		fsp->vfs_extension = next;

		if (curr->destroy) {
			curr->destroy(EXT_DATA_AREA(curr));
		}
		TALLOC_FREE(curr);
	}
}

void *vfs_memctx_fsp_extension(vfs_handle_struct *handle, files_struct *fsp)
{
	struct vfs_fsp_data *head;

	for (head = fsp->vfs_extension; head; head = head->next) {
		if (head->owner == handle) {
			return head;
		}
	}

	return NULL;
}

void *vfs_fetch_fsp_extension(vfs_handle_struct *handle, files_struct *fsp)
{
	struct vfs_fsp_data *head;

	head = (struct vfs_fsp_data *)vfs_memctx_fsp_extension(handle, fsp);
	if (head != NULL) {
		return EXT_DATA_AREA(head);
	}

	return NULL;
}

#undef EXT_DATA_AREA

/*
 * Ensure this module catches all VFS functions.
 */
#ifdef DEVELOPER
void smb_vfs_assert_all_fns(const struct vfs_fn_pointers* fns,
			    const char *module)
{
	bool missing_fn = false;
	unsigned int idx;
	const uintptr_t *end = (const uintptr_t *)(fns + 1);

	for (idx = 0; ((const uintptr_t *)fns + idx) < end; idx++) {
		if (*((const uintptr_t *)fns + idx) == 0) {
			DBG_ERR("VFS function at index %d not implemented "
				"in module %s\n", idx, module);
			missing_fn = true;
		}
	}

	if (missing_fn) {
		smb_panic("Required VFS function not implemented in module.\n");
	}
}
#else
void smb_vfs_assert_all_fns(const struct vfs_fn_pointers* fns,
			    const char *module)
{
}
#endif

/*****************************************************************
 Generic VFS init.
******************************************************************/

bool smbd_vfs_init(connection_struct *conn)
{
	const char **vfs_objects;
	unsigned int i = 0;
	int j = 0;

	/* Normal share - initialise with disk access functions */
	vfs_init_default(conn);

	/* No need to load vfs modules for printer connections */
	if (conn->printer) {
		return True;
	}

	vfs_objects = lp_vfs_objects(SNUM(conn));

	/* Override VFS functions if 'vfs object' was not specified*/
	if (!vfs_objects || !vfs_objects[0])
		return True;

	for (i=0; vfs_objects[i] ;) {
		i++;
	}

	for (j=i-1; j >= 0; j--) {
		if (!vfs_init_custom(conn, vfs_objects[j])) {
			DEBUG(0, ("smbd_vfs_init: vfs_init_custom failed for %s\n", vfs_objects[j]));
			return False;
		}
	}
	return True;
}

/*******************************************************************
 Check if a file exists in the vfs.
********************************************************************/

NTSTATUS vfs_file_exist(connection_struct *conn, struct smb_filename *smb_fname)
{
	/* Only return OK if stat was successful and S_ISREG */
	if ((SMB_VFS_STAT(conn, smb_fname) != -1) &&
	    S_ISREG(smb_fname->st.st_ex_mode)) {
		return NT_STATUS_OK;
	}

	return NT_STATUS_OBJECT_NAME_NOT_FOUND;
}

ssize_t vfs_pwrite_data(struct smb_request *req,
			files_struct *fsp,
			const char *buffer,
			size_t N,
			off_t offset)
{
	size_t total=0;
	ssize_t ret;

	if (req && req->unread_bytes) {
		int sockfd = req->xconn->transport.sock;
		SMB_ASSERT(req->unread_bytes == N);
		/* VFS_RECVFILE must drain the socket
		 * before returning. */
		req->unread_bytes = 0;
		/*
		 * Leave the socket non-blocking and
		 * use SMB_VFS_RECVFILE. If it returns
		 * EAGAIN || EWOULDBLOCK temporarily set
		 * the socket blocking and retry
		 * the RECVFILE.
		 */
		while (total < N) {
			ret = SMB_VFS_RECVFILE(sockfd,
						fsp,
						offset + total,
						N - total);
			if (ret == 0 || (ret == -1 &&
					 (errno == EAGAIN ||
					  errno == EWOULDBLOCK))) {
				int old_flags;
				/* Ensure the socket is blocking. */
				old_flags = fcntl(sockfd, F_GETFL, 0);
				if (set_blocking(sockfd, true) == -1) {
					return (ssize_t)-1;
				}
				ret = SMB_VFS_RECVFILE(sockfd,
							fsp,
							offset + total,
							N - total);
				if (fcntl(sockfd, F_SETFL, old_flags) == -1) {
					return (ssize_t)-1;
				}
				if (ret == -1) {
					return (ssize_t)-1;
				}
				total += ret;
				return (ssize_t)total;
			}
			/* Any other error case. */
			if (ret == -1) {
				return ret;
			}
			total += ret;
		}
		return (ssize_t)total;
	}

	while (total < N) {
		ret = SMB_VFS_PWRITE(fsp, buffer + total, N - total,
				     offset + total);

		if (ret == -1)
			return -1;
		if (ret == 0)
			return total;

		total += ret;
	}
	return (ssize_t)total;
}
/****************************************************************************
 An allocate file space call using the vfs interface.
 Allocates space for a file from a filedescriptor.
 Returns 0 on success, -1 on failure.
****************************************************************************/

int vfs_allocate_file_space(files_struct *fsp, uint64_t len)
{
	int ret;
	connection_struct *conn = fsp->conn;
	uint64_t space_avail;
	uint64_t bsize,dfree,dsize;
	NTSTATUS status;

	/*
	 * Actually try and commit the space on disk....
	 */

	DEBUG(10,("vfs_allocate_file_space: file %s, len %.0f\n",
		  fsp_str_dbg(fsp), (double)len));

	if (((off_t)len) < 0) {
		DEBUG(0,("vfs_allocate_file_space: %s negative len "
			 "requested.\n", fsp_str_dbg(fsp)));
		errno = EINVAL;
		return -1;
	}

	status = vfs_stat_fsp(fsp);
	if (!NT_STATUS_IS_OK(status)) {
		return -1;
	}

	if (len == (uint64_t)fsp->fsp_name->st.st_ex_size)
		return 0;

	if (len < (uint64_t)fsp->fsp_name->st.st_ex_size) {
		/* Shrink - use ftruncate. */

		DEBUG(10,("vfs_allocate_file_space: file %s, shrink. Current "
			  "size %.0f\n", fsp_str_dbg(fsp),
			  (double)fsp->fsp_name->st.st_ex_size));

		contend_level2_oplocks_begin(fsp, LEVEL2_CONTEND_ALLOC_SHRINK);

		flush_write_cache(fsp, SAMBA_SIZECHANGE_FLUSH);
		if ((ret = SMB_VFS_FTRUNCATE(fsp, (off_t)len)) != -1) {
			set_filelen_write_cache(fsp, len);
		}

		contend_level2_oplocks_end(fsp, LEVEL2_CONTEND_ALLOC_SHRINK);

		return ret;
	}

	/* Grow - we need to test if we have enough space. */

	contend_level2_oplocks_begin(fsp, LEVEL2_CONTEND_ALLOC_GROW);

	if (lp_strict_allocate(SNUM(fsp->conn))) {
		/* See if we have a syscall that will allocate beyond
		   end-of-file without changing EOF. */
		ret = SMB_VFS_FALLOCATE(fsp, VFS_FALLOCATE_FL_KEEP_SIZE,
					0, len);
	} else {
		ret = 0;
	}

	contend_level2_oplocks_end(fsp, LEVEL2_CONTEND_ALLOC_GROW);

	if (ret == 0) {
		/* We changed the allocation size on disk, but not
		   EOF - exactly as required. We're done ! */
		return 0;
	}

	if (ret == -1 && errno == ENOSPC) {
		return -1;
	}

	len -= fsp->fsp_name->st.st_ex_size;
	len /= 1024; /* Len is now number of 1k blocks needed. */
	space_avail =
	    get_dfree_info(conn, fsp->fsp_name, &bsize, &dfree, &dsize);
	if (space_avail == (uint64_t)-1) {
		return -1;
	}

	DEBUG(10,("vfs_allocate_file_space: file %s, grow. Current size %.0f, "
		  "needed blocks = %.0f, space avail = %.0f\n",
		  fsp_str_dbg(fsp), (double)fsp->fsp_name->st.st_ex_size, (double)len,
		  (double)space_avail));

	if (len > space_avail) {
		errno = ENOSPC;
		return -1;
	}

	return 0;
}

/****************************************************************************
 A vfs set_filelen call.
 set the length of a file from a filedescriptor.
 Returns 0 on success, -1 on failure.
****************************************************************************/

int vfs_set_filelen(files_struct *fsp, off_t len)
{
	int ret;

	contend_level2_oplocks_begin(fsp, LEVEL2_CONTEND_SET_FILE_LEN);

	DEBUG(10,("vfs_set_filelen: ftruncate %s to len %.0f\n",
		  fsp_str_dbg(fsp), (double)len));
	flush_write_cache(fsp, SAMBA_SIZECHANGE_FLUSH);
	if ((ret = SMB_VFS_FTRUNCATE(fsp, len)) != -1) {
		set_filelen_write_cache(fsp, len);
		notify_fname(fsp->conn, NOTIFY_ACTION_MODIFIED,
			     FILE_NOTIFY_CHANGE_SIZE
			     | FILE_NOTIFY_CHANGE_ATTRIBUTES,
			     fsp->fsp_name->base_name);
	}

	contend_level2_oplocks_end(fsp, LEVEL2_CONTEND_SET_FILE_LEN);

	return ret;
}

/****************************************************************************
 A slow version of fallocate. Fallback code if SMB_VFS_FALLOCATE
 fails. Needs to be outside of the default version of SMB_VFS_FALLOCATE
 as this is also called from the default SMB_VFS_FTRUNCATE code.
 Always extends the file size.
 Returns 0 on success, -1 on failure.
****************************************************************************/

#define SPARSE_BUF_WRITE_SIZE (32*1024)

int vfs_slow_fallocate(files_struct *fsp, off_t offset, off_t len)
{
	ssize_t pwrite_ret;
	size_t total = 0;

	if (!sparse_buf) {
		sparse_buf = SMB_CALLOC_ARRAY(char, SPARSE_BUF_WRITE_SIZE);
		if (!sparse_buf) {
			errno = ENOMEM;
			return -1;
		}
	}

	while (total < len) {
		size_t curr_write_size = MIN(SPARSE_BUF_WRITE_SIZE, (len - total));

		pwrite_ret = SMB_VFS_PWRITE(fsp, sparse_buf, curr_write_size, offset + total);
		if (pwrite_ret == -1) {
			int saved_errno = errno;
			DEBUG(10,("vfs_slow_fallocate: SMB_VFS_PWRITE for file "
				  "%s failed with error %s\n",
				  fsp_str_dbg(fsp), strerror(saved_errno)));
			errno = saved_errno;
			return -1;
		}
		total += pwrite_ret;
	}

	return 0;
}

/****************************************************************************
 A vfs fill sparse call.
 Writes zeros from the end of file to len, if len is greater than EOF.
 Used only by strict_sync.
 Returns 0 on success, -1 on failure.
****************************************************************************/

int vfs_fill_sparse(files_struct *fsp, off_t len)
{
	int ret;
	NTSTATUS status;
	off_t offset;
	size_t num_to_write;

	status = vfs_stat_fsp(fsp);
	if (!NT_STATUS_IS_OK(status)) {
		return -1;
	}

	if (len <= fsp->fsp_name->st.st_ex_size) {
		return 0;
	}

#ifdef S_ISFIFO
	if (S_ISFIFO(fsp->fsp_name->st.st_ex_mode)) {
		return 0;
	}
#endif

	DEBUG(10,("vfs_fill_sparse: write zeros in file %s from len %.0f to "
		  "len %.0f (%.0f bytes)\n", fsp_str_dbg(fsp),
		  (double)fsp->fsp_name->st.st_ex_size, (double)len,
		  (double)(len - fsp->fsp_name->st.st_ex_size)));

	contend_level2_oplocks_begin(fsp, LEVEL2_CONTEND_FILL_SPARSE);

	flush_write_cache(fsp, SAMBA_SIZECHANGE_FLUSH);

	offset = fsp->fsp_name->st.st_ex_size;
	num_to_write = len - fsp->fsp_name->st.st_ex_size;

	/* Only do this on non-stream file handles. */
	if (fsp->base_fsp == NULL) {
		/* for allocation try fallocate first. This can fail on some
		 * platforms e.g. when the filesystem doesn't support it and no
		 * emulation is being done by the libc (like on AIX with JFS1). In that
		 * case we do our own emulation. fallocate implementations can
		 * return ENOTSUP or EINVAL in cases like that. */
		ret = SMB_VFS_FALLOCATE(fsp, 0, offset, num_to_write);
		if (ret == -1 && errno == ENOSPC) {
			goto out;
		}
		if (ret == 0) {
			goto out;
		}
		DEBUG(10,("vfs_fill_sparse: SMB_VFS_FALLOCATE failed with "
			"error %d. Falling back to slow manual allocation\n", ret));
	}

	ret = vfs_slow_fallocate(fsp, offset, num_to_write);

 out:

	if (ret == 0) {
		set_filelen_write_cache(fsp, len);
	}

	contend_level2_oplocks_end(fsp, LEVEL2_CONTEND_FILL_SPARSE);
	return ret;
}

/****************************************************************************
 Transfer some data (n bytes) between two file_struct's.
****************************************************************************/

static ssize_t vfs_pread_fn(void *file, void *buf, size_t len, off_t offset)
{
	struct files_struct *fsp = (struct files_struct *)file;

	return SMB_VFS_PREAD(fsp, buf, len, offset);
}

static ssize_t vfs_pwrite_fn(void *file, const void *buf, size_t len, off_t offset)
{
	struct files_struct *fsp = (struct files_struct *)file;

	return SMB_VFS_PWRITE(fsp, buf, len, offset);
}

off_t vfs_transfer_file(files_struct *in, files_struct *out, off_t n)
{
	return transfer_file_internal((void *)in, (void *)out, n,
				      vfs_pread_fn, vfs_pwrite_fn);
}

/*******************************************************************
 A vfs_readdir wrapper which just returns the file name.
********************************************************************/

const char *vfs_readdirname(connection_struct *conn, void *p,
			    SMB_STRUCT_STAT *sbuf, char **talloced)
{
	struct dirent *ptr= NULL;
	const char *dname;
	char *translated;
	NTSTATUS status;

	if (!p)
		return(NULL);

	ptr = SMB_VFS_READDIR(conn, (DIR *)p, sbuf);
	if (!ptr)
		return(NULL);

	dname = ptr->d_name;


#ifdef NEXT2
	if (telldir(p) < 0)
		return(NULL);
#endif

#ifdef HAVE_BROKEN_READDIR_NAME
	/* using /usr/ucb/cc is BAD */
	dname = dname - 2;
#endif

	status = SMB_VFS_TRANSLATE_NAME(conn, dname, vfs_translate_to_windows,
					talloc_tos(), &translated);
	if (NT_STATUS_EQUAL(status, NT_STATUS_NONE_MAPPED)) {
		*talloced = NULL;
		return dname;
	}
	*talloced = translated;
	if (!NT_STATUS_IS_OK(status)) {
		return NULL;
	}
	return translated;
}

/*******************************************************************
 A wrapper for vfs_chdir().
********************************************************************/

int vfs_ChDir(connection_struct *conn, const struct smb_filename *smb_fname)
{
	int ret;
	int saved_errno = 0;
	struct smb_filename *old_cwd = conn->cwd_fname;

	if (!LastDir) {
		LastDir = SMB_STRDUP("");
	}

	if (ISDOT(smb_fname->base_name)) {
		return 0;
	}

	if (*smb_fname->base_name == '/' &&
			strcsequal(LastDir,smb_fname->base_name)) {
		return 0;
	}

	DEBUG(4,("vfs_ChDir to %s\n", smb_fname->base_name));

	ret = SMB_VFS_CHDIR(conn, smb_fname);
	if (ret != 0) {
		return -1;
	}

	/*
	 * Always replace conn->cwd_fname. We
	 * don't know if it's been modified by
	 * VFS modules in the stack.
	 */

	/* conn cache. */
	conn->cwd_fname = vfs_GetWd(conn, conn);
	if (conn->cwd_fname == NULL) {
		/*
		 * vfs_GetWd() failed.
		 * We must be able to read cwd.
		 * Return to original directory
		 * and return -1.
		 */
		saved_errno = errno;

		if (old_cwd == NULL) {
			/*
			 * Failed on the very first chdir()+getwd()
			 * for this connection. We can't
			 * continue.
			 */
			smb_panic("conn->cwd getwd failed\n");
			/* NOTREACHED */
			return -1;
		}
		/* Restore original conn->cwd_fname. */
		conn->cwd_fname = old_cwd;

		/* Return to the previous $cwd. */
		ret = SMB_VFS_CHDIR(conn, conn->cwd_fname);
		if (ret != 0) {
			smb_panic("conn->cwd getwd failed\n");
			/* NOTREACHED */
			return -1;
		}
		errno = saved_errno;
		/* And fail the chdir(). */
		return -1;
	}

	/* vfs_GetWd() succeeded. */
	/* Replace global cache. */
	SAFE_FREE(LastDir);
	LastDir = SMB_STRDUP(smb_fname->base_name);

	DEBUG(4,("vfs_ChDir got %s\n", conn->cwd_fname->base_name));

	TALLOC_FREE(old_cwd);
	if (saved_errno != 0) {
		errno = saved_errno;
	}
	return ret;
}

/*******************************************************************
 Return the absolute current directory path - given a UNIX pathname.
 Note that this path is returned in DOS format, not UNIX
 format. Note this can be called with conn == NULL.
********************************************************************/

struct smb_filename *vfs_GetWd(TALLOC_CTX *ctx, connection_struct *conn)
{
        struct smb_filename *current_dir_fname = NULL;
	struct file_id key;
	struct smb_filename *smb_fname_dot = NULL;
	struct smb_filename *smb_fname_full = NULL;
	struct smb_filename *result = NULL;

	if (!lp_getwd_cache()) {
		goto nocache;
	}

	smb_fname_dot = synthetic_smb_fname(ctx, ".", NULL, NULL, 0);
	if (smb_fname_dot == NULL) {
		errno = ENOMEM;
		goto out;
	}

	if (SMB_VFS_STAT(conn, smb_fname_dot) == -1) {
		/*
		 * Known to fail for root: the directory may be NFS-mounted
		 * and exported with root_squash (so has no root access).
		 */
		DEBUG(1,("vfs_GetWd: couldn't stat \".\" error %s "
			 "(NFS problem ?)\n", strerror(errno) ));
		goto nocache;
	}

	key = vfs_file_id_from_sbuf(conn, &smb_fname_dot->st);

	smb_fname_full = (struct smb_filename *)memcache_lookup_talloc(
					smbd_memcache(),
					GETWD_CACHE,
					data_blob_const(&key, sizeof(key)));

	if (smb_fname_full == NULL) {
		goto nocache;
	}

	if ((SMB_VFS_STAT(conn, smb_fname_full) == 0) &&
	    (smb_fname_dot->st.st_ex_dev == smb_fname_full->st.st_ex_dev) &&
	    (smb_fname_dot->st.st_ex_ino == smb_fname_full->st.st_ex_ino) &&
	    (S_ISDIR(smb_fname_dot->st.st_ex_mode))) {
		/*
		 * Ok, we're done
		 * Note: smb_fname_full is owned by smbd_memcache()
		 * so we must make a copy to return.
		 */
		result = cp_smb_filename(ctx, smb_fname_full);
		if (result == NULL) {
			errno = ENOMEM;
		}
		goto out;
	}

 nocache:

	/*
	 * We don't have the information to hand so rely on traditional
	 * methods. The very slow getcwd, which spawns a process on some
	 * systems, or the not quite so bad getwd.
	 */

	current_dir_fname = SMB_VFS_GETWD(conn, ctx);
	if (current_dir_fname == NULL) {
		DEBUG(0, ("vfs_GetWd: SMB_VFS_GETWD call failed: %s\n",
			  strerror(errno)));
		goto out;
	}

	if (lp_getwd_cache() && VALID_STAT(smb_fname_dot->st)) {
		key = vfs_file_id_from_sbuf(conn, &smb_fname_dot->st);

		/*
		 * smbd_memcache() will own current_dir_fname after the
		 * memcache_add_talloc call, so we must make
		 * a copy on ctx to return.
		 */
		result = cp_smb_filename(ctx, current_dir_fname);
		if (result == NULL) {
			errno = ENOMEM;
		}

		/*
		 * Ensure the memory going into the cache
		 * doesn't have a destructor so it can be
		 * cleanly freed.
		 */
		talloc_set_destructor(current_dir_fname, NULL);

		memcache_add_talloc(smbd_memcache(),
				GETWD_CACHE,
				data_blob_const(&key, sizeof(key)),
				&current_dir_fname);
		/* current_dir_fname is now == NULL here. */
	} else {
		/* current_dir_fname is already allocated on ctx. */
		result = current_dir_fname;
	}

 out:
	TALLOC_FREE(smb_fname_dot);
	/*
	 * Don't free current_dir_fname here. It's either been moved
	 * to the memcache or is being returned in result.
	 */
	return result;
}

/*******************************************************************
 Reduce a file name, removing .. elements and checking that
 it is below dir in the hierarchy. This uses realpath.
 This function must run as root, and will return names
 and valid stat structs that can be checked on open.
********************************************************************/

NTSTATUS check_reduced_name_with_privilege(connection_struct *conn,
			const struct smb_filename *smb_fname,
			struct smb_request *smbreq)
{
	NTSTATUS status;
	TALLOC_CTX *ctx = talloc_tos();
	const char *conn_rootdir;
	size_t rootdir_len;
	char *dir_name = NULL;
	char *resolved_name = NULL;
	const char *last_component = NULL;
	struct smb_filename *resolved_fname = NULL;
	struct smb_filename *saved_dir_fname = NULL;
	struct smb_filename *smb_fname_cwd = NULL;
	struct privilege_paths *priv_paths = NULL;
	int ret;

	DEBUG(3,("check_reduced_name_with_privilege [%s] [%s]\n",
			smb_fname->base_name,
			conn->connectpath));


	priv_paths = talloc_zero(smbreq, struct privilege_paths);
	if (!priv_paths) {
		status = NT_STATUS_NO_MEMORY;
		goto err;
	}

	if (!parent_dirname(ctx, smb_fname->base_name,
			&dir_name, &last_component)) {
		status = NT_STATUS_NO_MEMORY;
		goto err;
	}

	priv_paths->parent_name.base_name = talloc_strdup(priv_paths, dir_name);
	priv_paths->file_name.base_name = talloc_strdup(priv_paths, last_component);

	if (priv_paths->parent_name.base_name == NULL ||
			priv_paths->file_name.base_name == NULL) {
		status = NT_STATUS_NO_MEMORY;
		goto err;
	}

	if (SMB_VFS_STAT(conn, &priv_paths->parent_name) != 0) {
		status = map_nt_error_from_unix(errno);
		goto err;
	}
	/* Remember where we were. */
	saved_dir_fname = vfs_GetWd(ctx, conn);
	if (!saved_dir_fname) {
		status = map_nt_error_from_unix(errno);
		goto err;
	}

	if (vfs_ChDir(conn, &priv_paths->parent_name) == -1) {
		status = map_nt_error_from_unix(errno);
		goto err;
	}

	smb_fname_cwd = synthetic_smb_fname(talloc_tos(), ".", NULL, NULL, 0);
	if (smb_fname_cwd == NULL) {
		status = NT_STATUS_NO_MEMORY;
		goto err;
	}

	/* Get the absolute path of the parent directory. */
	resolved_fname = SMB_VFS_REALPATH(conn, ctx, smb_fname_cwd);
	if (resolved_fname == NULL) {
		status = map_nt_error_from_unix(errno);
		goto err;
	}
	resolved_name = resolved_fname->base_name;

	if (*resolved_name != '/') {
		DEBUG(0,("check_reduced_name_with_privilege: realpath "
			"doesn't return absolute paths !\n"));
		status = NT_STATUS_OBJECT_NAME_INVALID;
		goto err;
	}

	DEBUG(10,("check_reduced_name_with_privilege: realpath [%s] -> [%s]\n",
		priv_paths->parent_name.base_name,
		resolved_name));

	/* Now check the stat value is the same. */
	if (SMB_VFS_LSTAT(conn, smb_fname_cwd) != 0) {
		status = map_nt_error_from_unix(errno);
		goto err;
	}

	/* Ensure we're pointing at the same place. */
	if (!check_same_stat(&smb_fname_cwd->st, &priv_paths->parent_name.st)) {
		DEBUG(0,("check_reduced_name_with_privilege: "
			"device/inode/uid/gid on directory %s changed. "
			"Denying access !\n",
			priv_paths->parent_name.base_name));
		status = NT_STATUS_ACCESS_DENIED;
		goto err;
	}

	/* Ensure we're below the connect path. */

	conn_rootdir = SMB_VFS_CONNECTPATH(conn, smb_fname);
	if (conn_rootdir == NULL) {
		DEBUG(2, ("check_reduced_name_with_privilege: Could not get "
			"conn_rootdir\n"));
		status = NT_STATUS_ACCESS_DENIED;
		goto err;
	}

	rootdir_len = strlen(conn_rootdir);

	/*
	 * In the case of rootdir_len == 1, we know that conn_rootdir is
	 * "/", and we also know that resolved_name starts with a slash.
	 * So, in this corner case, resolved_name is automatically a
	 * sub-directory of the conn_rootdir. Thus we can skip the string
	 * comparison and the next character checks (which are even
	 * wrong in this case).
	 */
	if (rootdir_len != 1) {
		bool matched;

		matched = (strncmp(conn_rootdir, resolved_name,
				rootdir_len) == 0);

		if (!matched || (resolved_name[rootdir_len] != '/' &&
				 resolved_name[rootdir_len] != '\0')) {
			DEBUG(2, ("check_reduced_name_with_privilege: Bad "
				"access attempt: %s is a symlink outside the "
				"share path\n",
				dir_name));
			DEBUGADD(2, ("conn_rootdir =%s\n", conn_rootdir));
			DEBUGADD(2, ("resolved_name=%s\n", resolved_name));
			status = NT_STATUS_ACCESS_DENIED;
			goto err;
		}
	}

	/* Now ensure that the last component either doesn't
	   exist, or is *NOT* a symlink. */

	ret = SMB_VFS_LSTAT(conn, &priv_paths->file_name);
	if (ret == -1) {
		/* Errno must be ENOENT for this be ok. */
		if (errno != ENOENT) {
			status = map_nt_error_from_unix(errno);
			DEBUG(2, ("check_reduced_name_with_privilege: "
				"LSTAT on %s failed with %s\n",
				priv_paths->file_name.base_name,
				nt_errstr(status)));
			goto err;
		}
	}

	if (VALID_STAT(priv_paths->file_name.st) &&
			S_ISLNK(priv_paths->file_name.st.st_ex_mode)) {
		DEBUG(2, ("check_reduced_name_with_privilege: "
			"Last component %s is a symlink. Denying"
			"access.\n",
			priv_paths->file_name.base_name));
		status = NT_STATUS_ACCESS_DENIED;
		goto err;
	}

	smbreq->priv_paths = priv_paths;
	status = NT_STATUS_OK;

  err:

	if (saved_dir_fname != NULL) {
		vfs_ChDir(conn, saved_dir_fname);
		TALLOC_FREE(saved_dir_fname);
	}
	TALLOC_FREE(resolved_fname);
	if (!NT_STATUS_IS_OK(status)) {
		TALLOC_FREE(priv_paths);
	}
	TALLOC_FREE(dir_name);
	return status;
}

/*******************************************************************
 Reduce a file name, removing .. elements and checking that
 it is below dir in the hierarchy. This uses realpath.

 If cwd_name == NULL then fname is a client given path relative
 to the root path of the share.

 If cwd_name != NULL then fname is a client given path relative
 to cwd_name. cwd_name is relative to the root path of the share.
********************************************************************/

NTSTATUS check_reduced_name(connection_struct *conn,
				const struct smb_filename *cwd_fname,
				const struct smb_filename *smb_fname)
{
	TALLOC_CTX *ctx = talloc_tos();
	const char *cwd_name = cwd_fname ? cwd_fname->base_name : NULL;
	const char *fname = smb_fname->base_name;
	struct smb_filename *resolved_fname;
	char *resolved_name = NULL;
	char *new_fname = NULL;
	bool allow_symlinks = true;
	bool allow_widelinks = false;

	DBG_DEBUG("check_reduced_name [%s] [%s]\n", fname, conn->connectpath);

	resolved_fname = SMB_VFS_REALPATH(conn, ctx, smb_fname);

	if (resolved_fname == NULL) {
		switch (errno) {
			case ENOTDIR:
				DEBUG(3,("check_reduced_name: Component not a "
					 "directory in getting realpath for "
					 "%s\n", fname));
				return NT_STATUS_OBJECT_PATH_NOT_FOUND;
			case ENOENT:
			{
				char *dir_name = NULL;
				struct smb_filename dir_fname = {0};
				const char *last_component = NULL;

				/* Last component didn't exist.
				   Remove it and try and canonicalise
				   the directory name. */
				if (!parent_dirname(ctx, fname,
						&dir_name,
						&last_component)) {
					return NT_STATUS_NO_MEMORY;
				}

				dir_fname = (struct smb_filename)
					{ .base_name = dir_name };
				resolved_fname = SMB_VFS_REALPATH(conn,
							ctx,
							&dir_fname);
				if (resolved_fname == NULL) {
					NTSTATUS status = map_nt_error_from_unix(errno);

					if (errno == ENOENT || errno == ENOTDIR) {
						status = NT_STATUS_OBJECT_PATH_NOT_FOUND;
					}

					DEBUG(3,("check_reduce_name: "
						 "couldn't get realpath for "
						 "%s (%s)\n",
						fname,
						nt_errstr(status)));
					return status;
				}
				resolved_name = talloc_asprintf(ctx,
						"%s/%s",
						resolved_fname->base_name,
						last_component);
				if (resolved_name == NULL) {
					return NT_STATUS_NO_MEMORY;
				}
				break;
			}
			default:
				DEBUG(3,("check_reduced_name: couldn't get "
					 "realpath for %s\n", fname));
				return map_nt_error_from_unix(errno);
		}
	} else {
		resolved_name = resolved_fname->base_name;
	}

	DEBUG(10,("check_reduced_name realpath [%s] -> [%s]\n", fname,
		  resolved_name));

	if (*resolved_name != '/') {
		DEBUG(0,("check_reduced_name: realpath doesn't return "
			 "absolute paths !\n"));
		TALLOC_FREE(resolved_fname);
		return NT_STATUS_OBJECT_NAME_INVALID;
	}

	allow_widelinks = lp_widelinks(SNUM(conn));
	allow_symlinks = lp_follow_symlinks(SNUM(conn));

	/* Common widelinks and symlinks checks. */
	if (!allow_widelinks || !allow_symlinks) {
		const char *conn_rootdir;
		size_t rootdir_len;

		conn_rootdir = SMB_VFS_CONNECTPATH(conn, smb_fname);
		if (conn_rootdir == NULL) {
			DEBUG(2, ("check_reduced_name: Could not get "
				"conn_rootdir\n"));
			TALLOC_FREE(resolved_fname);
			return NT_STATUS_ACCESS_DENIED;
		}

		rootdir_len = strlen(conn_rootdir);

		/*
		 * In the case of rootdir_len == 1, we know that
		 * conn_rootdir is "/", and we also know that
		 * resolved_name starts with a slash.  So, in this
		 * corner case, resolved_name is automatically a
		 * sub-directory of the conn_rootdir. Thus we can skip
		 * the string comparison and the next character checks
		 * (which are even wrong in this case).
		 */
		if (rootdir_len != 1) {
			bool matched;

			matched = (strncmp(conn_rootdir, resolved_name,
					rootdir_len) == 0);
			if (!matched || (resolved_name[rootdir_len] != '/' &&
					 resolved_name[rootdir_len] != '\0')) {
				DEBUG(2, ("check_reduced_name: Bad access "
					"attempt: %s is a symlink outside the "
					"share path\n", fname));
				DEBUGADD(2, ("conn_rootdir =%s\n",
					     conn_rootdir));
				DEBUGADD(2, ("resolved_name=%s\n",
					     resolved_name));
				TALLOC_FREE(resolved_fname);
				return NT_STATUS_ACCESS_DENIED;
			}
		}

		/* Extra checks if all symlinks are disallowed. */
		if (!allow_symlinks) {
			/* fname can't have changed in resolved_path. */
			const char *p = &resolved_name[rootdir_len];

			/*
			 * UNIX filesystem semantics, names consisting
			 * only of "." or ".." CANNOT be symlinks.
			 */
			if (ISDOT(fname) || ISDOTDOT(fname)) {
				goto out;
			}

			if (*p != '/') {
				DEBUG(2, ("check_reduced_name: logic error (%c) "
					"in resolved_name: %s\n",
					*p,
					fname));
				TALLOC_FREE(resolved_fname);
				return NT_STATUS_ACCESS_DENIED;
			}

			p++;

			/*
			 * If cwd_name is present and not ".",
			 * then fname is relative to that, not
			 * the root of the share. Make sure the
			 * path we check is the one the client
			 * sent (cwd_name+fname).
			 */
			if (cwd_name != NULL && !ISDOT(cwd_name)) {
				new_fname = talloc_asprintf(ctx,
							"%s/%s",
							cwd_name,
							fname);
				if (new_fname == NULL) {
					TALLOC_FREE(resolved_fname);
					return NT_STATUS_NO_MEMORY;
				}
				fname = new_fname;
			}

			if (strcmp(fname, p)!=0) {
				DEBUG(2, ("check_reduced_name: Bad access "
					"attempt: %s is a symlink to %s\n",
					  fname, p));
				TALLOC_FREE(resolved_fname);
				TALLOC_FREE(new_fname);
				return NT_STATUS_ACCESS_DENIED;
			}
		}
	}

  out:

	DBG_INFO("%s reduced to %s\n", fname, resolved_name);
	TALLOC_FREE(resolved_fname);
	TALLOC_FREE(new_fname);
	return NT_STATUS_OK;
}

/**
 * XXX: This is temporary and there should be no callers of this once
 * smb_filename is plumbed through all path based operations.
 *
 * Called when we know stream name parsing has already been done.
 */
int vfs_stat_smb_basename(struct connection_struct *conn,
			const struct smb_filename *smb_fname_in,
			SMB_STRUCT_STAT *psbuf)
{
	struct smb_filename smb_fname = {
		.base_name = discard_const_p(char, smb_fname_in->base_name),
		.flags = smb_fname_in->flags
	};
	int ret;

	if (smb_fname.flags & SMB_FILENAME_POSIX_PATH) {
		ret = SMB_VFS_LSTAT(conn, &smb_fname);
	} else {
		ret = SMB_VFS_STAT(conn, &smb_fname);
	}

	if (ret != -1) {
		*psbuf = smb_fname.st;
	}
	return ret;
}

/**
 * Ensure LSTAT is called for POSIX paths.
 */

NTSTATUS vfs_stat_fsp(files_struct *fsp)
{
	int ret;

	if(fsp->fh->fd == -1) {
		if (fsp->posix_flags & FSP_POSIX_FLAGS_OPEN) {
			ret = SMB_VFS_LSTAT(fsp->conn, fsp->fsp_name);
		} else {
			ret = SMB_VFS_STAT(fsp->conn, fsp->fsp_name);
		}
		if (ret == -1) {
			return map_nt_error_from_unix(errno);
		}
	} else {
		if(SMB_VFS_FSTAT(fsp, &fsp->fsp_name->st) != 0) {
			return map_nt_error_from_unix(errno);
		}
	}
	return NT_STATUS_OK;
}

/**
 * Initialize num_streams and streams, then call VFS op streaminfo
 */
NTSTATUS vfs_streaminfo(connection_struct *conn,
			struct files_struct *fsp,
			const struct smb_filename *smb_fname,
			TALLOC_CTX *mem_ctx,
			unsigned int *num_streams,
			struct stream_struct **streams)
{
	*num_streams = 0;
	*streams = NULL;
	return SMB_VFS_STREAMINFO(conn,
			fsp,
			smb_fname,
			mem_ctx,
			num_streams,
			streams);
}

/*
  generate a file_id from a stat structure
 */
struct file_id vfs_file_id_from_sbuf(connection_struct *conn, const SMB_STRUCT_STAT *sbuf)
{
	return SMB_VFS_FILE_ID_CREATE(conn, sbuf);
}

/*
 * Design of the smb_vfs_ev_glue infrastructure:
 *
 * smb_vfs_ev_glue makes it possible to pass
 * down an tevent_context and pthreadpool_tevent
 * used for impersonation through the SMB_VFS stack.
 *
 * tevent_req based function take an tevent_context as
 * there 2nd argument, e.g.:
 *
 *   struct tevent_req *something_send(TALLOC_CTX *mem_ctx,
 *                                     struct tevent_context *ev,
 *                                     ...);
 *
 * For the SMB_VFS stack we'll use the following:
 *
 *   struct tevent_req *SMB_VFS_SOMETHING_SEND(TALLOC_CTX *mem_ctx,
 *                                             const struct smb_vfs_ev_glue *evg,
 *                                             ...);
 *
 * Typically the 'evg' is just passed through the stack down
 * to vfs_default.c. In order to do real work an
 * tevent_context and pthreadpool_tevent are required
 * to do call a 'somthing()' syscall in an async fashion.
 * Therefore it will the following to get the pointer
 * back out of evg:
 *
 *   ev = smb_vfs_ev_glue_ev_ctx(evg);
 *   tp = smb_vfs_ev_glue_tp_chdir_safe(evg);
 *
 * If some function in the stack is sure it needs to run as root
 * to get some information (after careful checks!), it used
 * to frame that work into become_root()/unbecome_root().
 * This can't work when using async functions!
 * Now it's possible to use something like this (simplified!):
 *
 *   ev = smb_vfs_ev_glue_ev_ctx(evg);
 *   root_evg = smb_vfs_ev_glue_get_root_glue(evg);
 *   subreq = SMB_VFS_SOMETHING_NEXT_SEND(state, root_evg, ...);
 *   if (tevent_req_nomem(subreq, req)) {
 *        return tevent_req_post(req, ev);
 *   }
 *   tevent_req_set_callback(subreq, module_something_done, req);
 *
 *   return req;
 *
 *   static void module_something_done(struct tevent_req *subreq)
 *   {
 *      ...
 *
 *      status = SMB_VFS_SOMETHING_NEXT_RECV(subreq, &state->aio_state);
 *      TALLOC_FREE(subreq);
 *
 *      tevent_req_done(req);
 *   }
 *
 * In the code above the something_send_fn() function of the next
 * module in the stack will be called as root.
 * The smb_vfs_call_something_*() glue code, which is the magic
 * behind the SMB_VFS_SOMETHING[_NEXT]_{SEND,RECV}() macros,
 * will look like this:
 *
 *   struct smb_vfs_call_something_state {
 *       ssize_t (*recv_fn)(struct tevent_req *req,
 *                          struct vfs_aio_state *aio_state,
 *                          ...);
 *       ssize_t retval;
 *       struct vfs_aio_state vfs_aio_state;
 *       ...
 *   };
 *
 *   static void smb_vfs_call_something_done(struct tevent_req *subreq);
 *
 *   struct tevent_req *smb_vfs_call_something_send(
 *                  TALLOC_CTX *mem_ctx,
 *                  const struct smb_vfs_ev_glue *evg,
 *                  struct vfs_handle_struct *handle,
 *                  ...)
 *   {
 *       struct tevent_req *req = NULL;
 *       struct smb_vfs_call_something_state *state = NULL;
 *       struct tevent_req *subreq = NULL;
 *       bool ok;
 *
 *       req = tevent_req_create(mem_ctx, &state,
 *                               struct smb_vfs_call_something_state);
 *       if (req == NULL) {
 *           return NULL;
 *       }
 *
 *       VFS_FIND(something_send);
 *       state->recv_fn = handle->fns->something_recv_fn;
 *
 *       ok = smb_vfs_ev_glue_push_use(evg, req);
 *       if (!ok) {
 *           tevent_req_error(req, EIO);
 *           return tevent_req_post(req, evg->return_ev);
 *       }
 *
 *       subreq = handle->fns->something_send_fn(mem_ctx,
 *                                               evg->next_glue,
 *                                               handle,
 *                                               ...);
 *       smb_vfs_ev_glue_pop_use(evg);
 *
 *       if (tevent_req_nomem(subreq, req)) {
 *           return tevent_req_post(req, evg->return_ev);
 *       }
 *       tevent_req_set_callback(subreq, smb_vfs_call_something_done, req);
 *
 *       return req;
 *   }
 *
 *   static void smb_vfs_call_something_done(struct tevent_req *subreq)
 *   {
 *       struct tevent_req *req =
 *           tevent_req_callback_data(subreq,
 *           struct tevent_req);
 *       struct smb_vfs_call_something_state *state =
 *           tevent_req_data(req,
 *           struct smb_vfs_call_something_state);
 *
 *       state->retval = state->recv_fn(subreq,
 *                                      &state->vfs_aio_state,
 *                                      ....);
 *       TALLOC_FREE(subreq);
 *
 *       if (state->retval == -1) {
 *           tevent_req_error(req, state->vfs_aio_state.error);
 *           return;
 *       }
 *       tevent_req_done(req);
 *   }
 *
 *   ssize_t smb_vfs_call_something_recv(struct tevent_req *req,
 *                                        struct vfs_aio_state *aio_state,
 *                                        ....)
 *   {
 *       struct smb_vfs_call_something_state *state =
 *           tevent_req_data(req,
 *           struct smb_vfs_call_something_state);
 *       ssize_t retval = state->retval;
 *
 *       if (tevent_req_is_unix_error(req, &aio_state->error)) {
 *           tevent_req_received(req);
 *           return -1;
 *       }
 *
 *       *aio_state = state->vfs_aio_state;
 *       ...
 *
 *       tevent_req_received(req);
 *       return retval;
 *   }
 *
 * The most important details are these:
 *
 * 1. smb_vfs_ev_glue_push_use(evg, req):
 *    - is a no-op if evg->run_ev and evg->return_ev are the same,
 *      it means that we're already at the correct impersonation
 *      and don't need any additional work to be done.
 *    - Otherwise it will call tevent_req_defer_callback(req, evg->return_ev)
 *      This means that tevent_req_error() and tevent_req_done()
 *      will just trigger an immediate event on evg->return_ev.
 *      Therefore the callers callback function will be called
 *      in the impersonation of evg->return_ev! This is important
 *      in order to get the impersonation correct on the way back
 *      through the stack.
 *    - It will call tevent_context_push_use(evg->run_ev),
 *      which will start the impersonation to run_ev.
 *      So the following code run in the correct context.
 * 2. handle->fns->something_send_fn(..., evg->next_glue, ...):
 *    - We're passing evg->next_glue to the next module.
 *    - Typically evg->next_glue points to evg again.
 *    - In case evg->run_ev and evg->return_ev are not the same,
 *      next_glue will have run_ev and return_ev pointing to evg->run_ev.
 *      So that the switch from evg->run_ev to evg->return_ev
 *      happens on the correct boundary.
 * 3. smb_vfs_ev_glue_pop_use(evg):
 *    - is a no-op if evg->run_ev and evg->return_ev are the same,
 *      it means that we're already at the correct impersonation
 *      and don't need any additional work to be done.
 *    - It will call tevent_context_pop_use(evg->run_ev),
 *      which will revert the impersonation done in
 *      smb_vfs_ev_glue_push_use().
 * 4. smb_vfs_call_something_send():
 *    - The is called in the environment of evg->return_ev.
 *    - So it needs to use tevent_req_post(req, evg->return_ev)
 * 5. smb_vfs_call_something_done():
 *    - The is called in the environment of evg->run_ev
 * 6. smb_vfs_call_something_recv():
 *    - The is called in the environment of evg->return_ev again.
 *
 *
 * Here are some more complex examples:
 *
 * Example 1: only user_evg without switch to root
 *
 * SMBD: already impersonated user_evg
 *  evg'1 = smb2_req->user_evg
 *  r'1 = SMB_VFS_*_SEND(evg'1); # smb_vfs_call_*_send()
 *  |
 *  | smb_vfs_ev_glue_push_use(evg'1, r'1);
 *  | |
 *  | | # no-op run_ev == return_ev
 *  | |
 *  | evg'2 = evg'1->next_glue;
 *  | r'2 = module1_*_send(evg'2);
 *  | |
 *  | | evg'3 = evg'2
 *  | | r'3 = SMB_VFS_*_NEXT_SEND(evg'3); # smb_vfs_call_*_send()
 *  | | |
 *  | | | smb_vfs_ev_glue_push_use(evg'3, r'3);
 *  | | | |
 *  | | | | # no-op run_ev == return_ev
 *  | | | |
 *  | | | evg'4 = evg'3->next_glue;
 *  | | | r'4 = module2_*_send(evg'4);
 *  | | | |
 *  | | | | evg'5 = evg'4
 *  | | | | r'5 = SMB_VFS_*_NEXT_SEND(evg'5); # smb_vfs_call_*_send()
 *  | | | | |
 *  | | | | | smb_vfs_ev_glue_push_use(evg'5, r'5);
 *  | | | | | |
 *  | | | | | | # no-op run_ev == return_ev
 *  | | | | | |
 *  | | | | | evg'6 = evg'5->next_glue;
 *  | | | | | r'6 = default_*_send(evg'6);
 *  | | | | | |
 *  | | | | | | ev'6 = smb_vfs_ev_glue_ev_ctx(evg'6)
 *  | | | | | | tp'6 = smb_vfs_ev_glue_tp_chdir_safe(evg'6)
 *  | | | | | | r'7 = pthreadpool_tevent_send(ev'6, tp'6);
 *  | | | | | | |
 *  | | | | | | | pthread_create...
 *  | | | | | | |
 *  | | | | | | tevent_req_set_callback(r'7, default_*_done, r'6);
 *  | | | | | |
 *  | | | | | smb_vfs_ev_glue_pop_use(evg'5);
 *  | | | | | |
 *  | | | | | | # no-op run_ev == return_ev
 *  | | | | | |
 *  | | | | | tevent_req_set_callback(r'6, smb_vfs_call_*_done, r'5);
 *  | | | | |
 *  | | | | tevent_req_set_callback(r'5, module2_*_done, r'4);
 *  | | | |
 *  | | | smb_vfs_ev_glue_pop_use(evg'3);
 *  | | | |
 *  | | | | # no-op run_ev == return_ev
 *  | | | |
 *  | | | tevent_req_set_callback(r'4, smb_vfs_call_*_done, r'3);
 *  | | |
 *  | | tevent_req_set_callback(r'3, module1_*_done, r'2);
 *  | |
 *  | smb_vfs_ev_glue_pop_use(evg'1);
 *  | |
 *  | | # no-op run_ev == return_ev
 *  | |
 *  | tevent_req_set_callback(r'2, smb_vfs_call_*_done, r'1);
 *  |
 *  tevent_req_set_callback(r'1, smbd_*_done, smb2_req);
 *
 *  Worker thread finished, just one event handler processes
 *  everything as there's no impersonation change.
 *
 *  tevent_common_invoke_immediate_handler:
 *  |
 *  | before_immediate_handler(ev'6);
 *  | |
 *  | | change_to_user()
 *  | |
 *  | pthreadpool_tevent_job_done(r'7);
 *  | |
 *  | | default_*_done(r'7);
 *  | | |
 *  | | | pthreadpool_tevent_recv(r'7);
 *  | | | TALLOC_FREE(r'7);
 *  | | | tevent_req_done('r6);
 *  | | | |
 *  | | | | smb_vfs_call_*_done(r'6);
 *  | | | | |
 *  | | | | | default_*_recv(r'6);
 *  | | | | | TALLOC_FREE(r'6)
 *  | | | | | tevent_req_done(r'5);
 *  | | | | | |
 *  | | | | | | module2_*_done(r'5):
 *  | | | | | | |
 *  | | | | | | | SMB_VFS_*_recv(r'5); # smb_vfs_call_*_recv()
 *  | | | | | | | TALLOC_FREE(r'5)
 *  | | | | | | | tevent_req_done(r'4);
 *  | | | | | | | |
 *  | | | | | | | | smb_vfs_call_*_done(r'4);
 *  | | | | | | | | |
 *  | | | | | | | | | module2_*_recv(r'4);
 *  | | | | | | | | | TALLOC_FREE(r'4)
 *  | | | | | | | | | tevent_req_done(r'3);
 *  | | | | | | | | | |
 *  | | | | | | | | | | module1_*_done(r'3):
 *  | | | | | | | | | | |
 *  | | | | | | | | | | | SMB_VFS_*_recv(r'3); # smb_vfs_call_*_recv()
 *  | | | | | | | | | | | TALLOC_FREE(r'3)
 *  | | | | | | | | | | | tevent_req_done(r'2);
 *  | | | | | | | | | | | |
 *  | | | | | | | | | | | | smb_vfs_*_done(r'2);
 *  | | | | | | | | | | | | |
 *  | | | | | | | | | | | | | module1_*_recv(r'2);
 *  | | | | | | | | | | | | | TALLOC_FREE(r'2)
 *  | | | | | | | | | | | | | tevent_req_done(r'1);
 *  | | | | | | | | | | | | | |
 *  | | | | | | | | | | | | | | smbd_*_done(r'1);
 *  | | | | | | | | | | | | | | |
 *  | | | | | | | | | | | | | | | SMB_VFS_*_recv(r'1); # smb_vfs_call_*_recv()
 *  | | | | | | | | | | | | | | | TALLOC_FREE(r'1)
 *  | | | | | | | | | | | | | | | smbd_response_to_client()
 *  | | | | | | | | | | | | | | | return
 *  | | | | | | | | | | | | | | |
 *  | | | | | | | | | | | | | | return
 *  | | | | | | | | | | | | | |
 *  | | | | | | | | | | | | | return
 *  | | | | | | | | | | | | |
 *  | | | | | | | | | | | | return
 *  | | | | | | | | | | | |
 *  | | | | | | | | | | | return
 *  | | | | | | | | | | |
 *  | | | | | | | | | | return
 *  | | | | | | | | | |
 *  | | | | | | | | | return
 *  | | | | | | | | |
 *  | | | | | | | | return
 *  | | | | | | | |
 *  | | | | | | | return
 *  | | | | | | |
 *  | | | | | | return
 *  | | | | | |
 *  | | | | | return
 *  | | | | |
 *  | | | | return
 *  | | | |
 *  | | | return
 *  | | |
 *  | | return
 *  | |
 *  | after_immediate_handler(ev'6);
 *  | |
 *  | | # lazy no change_to_user()
 *  | |
 *  | return
 *
 *
 * Example 2: start with user_evg and let module1 switch to root
 *
 * SMBD: already impersonated user_evg
 *  evg'1 = smb2_req->user_evg
 *  r'1 = SMB_VFS_*_SEND(evg'1); # smb_vfs_call_*_send()
 *  |
 *  | smb_vfs_ev_glue_push_use(evg'1, r'1);
 *  | |
 *  | | # no-op run_ev == return_ev
 *  | |
 *  | evg'2 = evg'1->next_glue;
 *  | r'2 = module1_*_send(evg'2);
 *  | |
 *  | | evg'3 = smb_vfs_ev_glue_get_root_glue(evg'2)
 *  | | r'3 = SMB_VFS_*_NEXT_SEND(evg'3); # smb_vfs_call_*_send()
 *  | | |
 *  | | | smb_vfs_ev_glue_push_use(evg'3, r'3);
 *  | | | |
 *  | | | | tevent_req_defer_callback(r'3, evg'3->return_ev);
 *  | | | | tevent_context_push_use(evg'3->run_ev)
 *  | | | | |
 *  | | | | | become_root()
 *  | | | | |
 *  | | | |
 *  | | | evg'4 = evg'3->next_glue;
 *  | | | r'4 = module2_*_send(evg'4);
 *  | | | |
 *  | | | | evg'5 = smb_vfs_ev_glue_get_root_glue(evg'4)
 *  | | | | r'5 = SMB_VFS_*_NEXT_SEND(evg'5); # smb_vfs_call_*_send()
 *  | | | | |
 *  | | | | | smb_vfs_ev_glue_push_use(evg'5, r'5);
 *  | | | | | |
 *  | | | | | | # no-op run_ev == return_ev, already root
 *  | | | | | |
 *  | | | | | evg'6 = evg'5->next_glue;
 *  | | | | | r'6 = default_*_send(evg'6);
 *  | | | | | |
 *  | | | | | | ev'6 = smb_vfs_ev_glue_ev_ctx(evg'6)
 *  | | | | | | tp'6 = smb_vfs_ev_glue_tp_chdir_safe(evg'6)
 *  | | | | | | r'7 = pthreadpool_tevent_send(ev'6, tp'6);
 *  | | | | | | |
 *  | | | | | | | pthread_create...
 *  | | | | | | |
 *  | | | | | | tevent_req_set_callback(r'7, default_*_done, r'6);
 *  | | | | | |
 *  | | | | | smb_vfs_ev_glue_pop_use(evg'5);
 *  | | | | | |
 *  | | | | | | # no-op run_ev == return_ev, still stay as root
 *  | | | | | |
 *  | | | | | tevent_req_set_callback(r'6, smb_vfs_*_done, r'5);
 *  | | | | |
 *  | | | | tevent_req_set_callback(r'5, module2_*_done, r'4);
 *  | | | |
 *  | | | smb_vfs_ev_glue_pop_use(evg'3);
 *  | | | |
 *  | | | | tevent_context_pop_use(evg'3->run_ev)
 *  | | | | |
 *  | | | | | unbecome_root()
 *  | | | |
 *  | | | tevent_req_set_callback(r'4, smb_vfs_*_done, r'3);
 *  | | |
 *  | | tevent_req_set_callback(r'3, module1_*_done, r'2);
 *  | |
 *  | smb_vfs_ev_glue_pop_use(evg'1);
 *  | |
 *  | | # no-op run_ev == return_ev
 *  | |
 *  | tevent_req_set_callback(r'2, smb_vfs_*_done, r'1);
 *  |
 *  tevent_req_set_callback(r'1, smbd_*_done, smb2_req);
 *
 *  Worker thread finished, just one event handler processes
 *  everything as there's no impersonation change.
 *
 *  tevent_common_invoke_immediate_handler:
 *  |
 *  | before_immediate_handler(ev'6);
 *  | |
 *  | | become_root()
 *  | |
 *  | pthreadpool_tevent_job_done(r'7);
 *  | |
 *  | | default_*_done(r'7);
 *  | | |
 *  | | | pthreadpool_tevent_recv(r'7);
 *  | | | TALLOC_FREE(r'7);
 *  | | | tevent_req_done('r6);
 *  | | | |
 *  | | | | smb_vfs_*_done(r'6);
 *  | | | | |
 *  | | | | | default_*_recv(r'6);
 *  | | | | | TALLOC_FREE(r'6)
 *  | | | | | tevent_req_done(r'5);
 *  | | | | | |
 *  | | | | | | module2_*_done(r'5):
 *  | | | | | | |
 *  | | | | | | | SMB_VFS_*_recv(r'5);
 *  | | | | | | | TALLOC_FREE(r'5)
 *  | | | | | | | tevent_req_done(r'4);
 *  | | | | | | | |
 *  | | | | | | | | smb_vfs_*_done(r'4);
 *  | | | | | | | | |
 *  | | | | | | | | | module2_*_recv(r'4);
 *  | | | | | | | | | TALLOC_FREE(r'4)
 *  | | | | | | | | | tevent_req_done(r'3);
 *  | | | | | | | | | | return
 *  | | | | | | | | | |
 *  | | | | | | | | | return
 *  | | | | | | | | |
 *  | | | | | | | | return
 *  | | | | | | | |
 *  | | | | | | | return
 *  | | | | | | |
 *  | | | | | | return
 *  | | | | | |
 *  | | | | | return
 *  | | | | |
 *  | | | | return
 *  | | | |
 *  | | | return
 *  | | |
 *  | | return
 *  | |
 *  | |
 *  | after_immediate_handler(ev'6);
 *  | |
 *  | | unbecome_root()
 *  | |
 *  | return
 *  |
 *  tevent_common_invoke_immediate_handler:
 *  |
 *  | before_immediate_handler(ev'6);
 *  | |
 *  | | change_to_user()
 *  | |
 *  | tevent_req_trigger();
 *  | ...
 *  | _tevent_req_notify_callback(r'3)
 *  | |
 *  | | module1_*_done(r'3):
 *  | | |
 *  | | | SMB_VFS_*_recv(r'3);
 *  | | | TALLOC_FREE(r'3)
 *  | | | tevent_req_done(r'2);
 *  | | | |
 *  | | | | smb_vfs_*_done(r'2);
 *  | | | | |
 *  | | | | | module1_*_recv(r'2);
 *  | | | | | TALLOC_FREE(r'2)
 *  | | | | | tevent_req_done(r'1);
 *  | | | | | |
 *  | | | | | | smbd_*_done(r'1);
 *  | | | | | | |
 *  | | | | | | | SMB_VFS_*_recv(r'1);
 *  | | | | | | | TALLOC_FREE(r'1)
 *  | | | | | | | smbd_response_to_client()
 *  | | | | | | | return
 *  | | | | | | |
 *  | | | | | | return
 *  | | | | | |
 *  | | | | | return
 *  | | | | |
 *  | | | | return
 *  | | | |
 *  | | | return
 *  | | |
 *  | | return
 *  | |
 *  | after_immediate_handler(ev'6);
 *  | |
 *  | | # lazy no change_to_user()
 *  | |
 *  | return
 *
 */
struct smb_vfs_ev_glue {
	/*
	 * The event context that should be used
	 * to report the result back.
	 *
	 * The is basically the callers context.
	 */
	struct tevent_context *return_ev;

	/*
	 * The event context and threadpool wrappers
	 * the current context should use.
	 *
	 * tp_fd_safe only allows fd based functions
	 * which don't require impersonation, this
	 * is basically the raw threadpool.
	 *
	 * tp_path_safe allows path based functions
	 * to be called under the correct impersonation.
	 * But chdir/fchdir is not allowed!
	 * Typically calls like openat() or other *at()
	 * syscalls.
	 *
	 * tp_chdir_safe is like path_safe, but also
	 * allows chdir/fchdir to be called, the job
	 * can safely return with a changed directory,
	 * the threadpool wrapper takes care of
	 * a cleanup if required.
	 * This is needed if *at() syscalls need
	 * to be simulated by fchdir();$syscall(),
	 * e.g. getxattr().
	 *
	 * The distinction between these threadpool
	 * is required because of OS limitations
	 * (as of 2018):
	 * - only Linux supports per thread
	 *   credentials (seteuid....)
	 * - only Linux supports a per thread
	 *   current working directory,
	 *   using unshare(CLONE_FS). But
	 *   in some constrained container
	 *   environments even that is not available
	 *   on Linux.
	 *
	 * tp_fd_safe is typically the raw threadpool
	 * without a wrapper.
	 *
	 * On Linux tp_path_safe and tp_chdir_safe
	 * are typically the same (if unshare(CLONE_FS) is available)
	 * they're implemented as wrappers of the raw threadpool.
	 *
	 * On other OSes tp_path_safe is a wrapper
	 * arround a sync threadpool (without real threads, just blocking
	 * the main thread), but hidden behind the pthreadpool_tevent
	 * api in order to make the restriction transparent.
	 *
	 * On other OSes tp_chdir_safe is a wrapper
	 * arround a sync threadpool (without real threads, just blocking
	 * the main thread), but hidden behind the pthreadpool_tevent
	 * api in order to make the restriction transparent.
	 * It just remembers/restores the current working directory,
	 * typically using open(".", O_RDONLY | O_DIRECTORY) and fchdir().
	 */
	struct tevent_context *run_ev;
	struct pthreadpool_tevent *run_tp_fd_safe;
	struct pthreadpool_tevent *run_tp_path_safe;
	struct pthreadpool_tevent *run_tp_chdir_safe;

	/*
	 * The glue that should be passed down
	 * to sub request in the stack.
	 *
	 * Typically this points to itself.
	 *
	 * But smb_vfs_ev_glue_create_switch() allows
	 * to create context that can switch
	 * between two user glues.
	 */
	const struct smb_vfs_ev_glue *next_glue;

	/*
	 * If some code path wants to run
	 * some constraint code as root,
	 * basically an async version of become_root()
	 * and unbecome_root().
	 *
	 * The caller can call smb_vfs_ev_glue_get_root_glue()
	 * to get a root glue that can be passed
	 * to the SMB_VFS_*_SEND() function that
	 * should run as root.
	 *
	 * Note that the callback (registered with
	 * tevent_req_set_callback()) won't run as
	 * root anymore!
	 */
	const struct smb_vfs_ev_glue *root_glue;
};

static struct smb_vfs_ev_glue *smb_vfs_ev_glue_create_internal(
	TALLOC_CTX *mem_ctx,
	struct tevent_context *return_ev,
	struct tevent_context *run_ev,
	struct pthreadpool_tevent *run_tp_fd_safe,
	struct pthreadpool_tevent *run_tp_path_safe,
	struct pthreadpool_tevent *run_tp_chdir_safe)
{
	struct smb_vfs_ev_glue *evg = NULL;

	evg = talloc_zero(mem_ctx, struct smb_vfs_ev_glue);
	if (evg == NULL) {
		return NULL;
	}
	*evg = (struct smb_vfs_ev_glue) {
		.return_ev = return_ev,
		.run_ev = run_ev,
		.run_tp_fd_safe = run_tp_fd_safe,
		.run_tp_path_safe = run_tp_path_safe,
		.run_tp_chdir_safe = run_tp_chdir_safe,
		.next_glue = evg,
	};

	return evg;
}

struct tevent_context *smb_vfs_ev_glue_ev_ctx(const struct smb_vfs_ev_glue *evg)
{
	return evg->run_ev;
}

struct pthreadpool_tevent *smb_vfs_ev_glue_tp_fd_safe(const struct smb_vfs_ev_glue *evg)
{
	return evg->run_tp_fd_safe;
}

struct pthreadpool_tevent *smb_vfs_ev_glue_tp_path_safe(const struct smb_vfs_ev_glue *evg)
{
	return evg->run_tp_path_safe;
}

struct pthreadpool_tevent *smb_vfs_ev_glue_tp_chdir_safe(const struct smb_vfs_ev_glue *evg)
{
	return evg->run_tp_chdir_safe;
}

const struct smb_vfs_ev_glue *smb_vfs_ev_glue_get_root_glue(const struct smb_vfs_ev_glue *evg)
{
	return evg->root_glue;
}

struct smb_vfs_ev_glue *smb_vfs_ev_glue_create(TALLOC_CTX *mem_ctx,
				struct tevent_context *user_ev,
				struct pthreadpool_tevent *user_tp_fd_safe,
				struct pthreadpool_tevent *user_tp_path_safe,
				struct pthreadpool_tevent *user_tp_chdir_safe,
				struct tevent_context *root_ev,
				struct pthreadpool_tevent *root_tp_fd_safe,
				struct pthreadpool_tevent *root_tp_path_safe,
				struct pthreadpool_tevent *root_tp_chdir_safe)
{
	struct smb_vfs_ev_glue *evg_uu = NULL;
	struct smb_vfs_ev_glue *evg_ru = NULL;
	struct smb_vfs_ev_glue *evg_rr = NULL;

	/*
	 * The top level glue (directly returned from this function).
	 *
	 * It uses user_ev and user_tp_* only.
	 */
	evg_uu = smb_vfs_ev_glue_create_internal(mem_ctx,
						 user_ev, /* return_ev */
						 user_ev, /* run_ev */
						 user_tp_fd_safe,
						 user_tp_path_safe,
						 user_tp_chdir_safe);
	if (evg_uu == NULL) {
		return NULL;
	}

	/*
	 * The first root glue (returned by smb_vfs_ev_glue_get_root_glue()).
	 *
	 * It uses root_ev and root_tp, but user_ev as return ev,
	 * which means that the caller's callback (registered with
	 * tevent_req_set_callback()) will run as user_ev.
	 */
	evg_ru = smb_vfs_ev_glue_create_internal(evg_uu,
						 user_ev, /* return_ev */
						 root_ev, /* run_ev */
						 root_tp_fd_safe,
						 root_tp_path_safe,
						 root_tp_chdir_safe);
	if (evg_ru == NULL) {
		TALLOC_FREE(evg_uu);
		return NULL;
	}

	/*
	 * The second root glue (returned by smb_vfs_ev_glue_get_root_glue() on
	 * root glue itself. This means code can always call
	 * smb_vfs_ev_glue_get_root_glue() and don't have to care if the
	 * passed glue is already a root glue.
	 *
	 * This will then recursively point to its own root_glue pointer.
	 *
	 * It only uses root_ev and root_tp.
	 */
	evg_rr = smb_vfs_ev_glue_create_internal(evg_ru,
						 root_ev, /* return_ev */
						 root_ev, /* run_ev */
						 root_tp_fd_safe,
						 root_tp_path_safe,
						 root_tp_chdir_safe);
	if (evg_rr == NULL) {
		TALLOC_FREE(evg_uu);
		return NULL;
	}

	/*
	 * We now setup the glue hierarchy.
	 *
	 * Search for "Design of the smb_vfs_ev_glue infrastructure" above
	 * for a detailed description how the chain works.
	 *
	 * "Example 2: start with user_evg and let module1 switch to root"
	 * explains it for the root_glue chaining.
	 */
	evg_rr->root_glue = evg_rr;
	evg_ru->root_glue = evg_rr;
	evg_uu->root_glue = evg_ru;

	/*
	 * As evg_ru is a boundary with
	 * run_ev != return_ev, we need to
	 * alter its next_glue.
	 */
	evg_ru->next_glue = evg_rr;

	return evg_uu;
}

/*
 * This can be used to create a temporary glue
 * if you need to switch between two user contexts
 *
 * It's the caller's duty to make sure both
 * glues stay alive for the lifetime of the
 * created switch.
 */
struct smb_vfs_ev_glue *smb_vfs_ev_glue_create_switch(
			TALLOC_CTX *mem_ctx,
			const struct smb_vfs_ev_glue *return_evg,
			const struct smb_vfs_ev_glue *run_evg)
{
	const struct smb_vfs_ev_glue *run_root = run_evg->root_glue;
	struct smb_vfs_ev_glue *evg_u = NULL;
	struct smb_vfs_ev_glue *evg_r = NULL;

	/*
	 * Here we basically need to dup run_evg (and run_evg->root_glue)
	 * and replace their return_ev with return_evg->return_ev.
	 *
	 * We need to put the new evgs in front of the chain...
	 */
	evg_u = smb_vfs_ev_glue_create_internal(mem_ctx,
						return_evg->return_ev,
						run_evg->run_ev,
						run_evg->run_tp_fd_safe,
						run_evg->run_tp_path_safe,
						run_evg->run_tp_chdir_safe);
	if (evg_u == NULL) {
		return NULL;
	}

	evg_r = smb_vfs_ev_glue_create_internal(evg_u,
						return_evg->return_ev,
						run_root->run_ev,
						run_root->run_tp_fd_safe,
						run_root->run_tp_path_safe,
						run_root->run_tp_chdir_safe);
	if (evg_r == NULL) {
		return NULL;
	}

	/*
	 * evg_r is a boundary with run_ev != return_ev.
	 * As run_root is also a boundary, we need to
	 * use run_root->next_glue in order to get
	 * a glue that stays as root.
	 *
	 * The same applies to the chaining of root
	 * glues.
	 */
	evg_r->next_glue = run_root->next_glue;
	evg_r->root_glue = run_root->root_glue;

	/*
	 * evg_r is a boundary with run_ev != return_ev.
	 * But run_evg is typically not a boundary,
	 * we use it directly as next_glue.
	 *
	 * And the root_glue is the one we constructed above.
	 */
	evg_u->next_glue = run_evg;
	evg_u->root_glue = evg_r;

	return evg_u;
}

static bool smb_vfs_ev_glue_push_use(const struct smb_vfs_ev_glue *evg,
				     struct tevent_req *req)
{
	if (evg->run_ev == evg->return_ev) {
		/*
		 * We're already in the correct
		 * impersonation environment.
		 */
		return true;
	}

	/*
	 * Make sure that our callers callback function
	 * will be called in the return_ev environment.
	 */
	tevent_req_defer_callback(req, evg->return_ev);

	/*
	 * let the event context wrapper do
	 * the required impersonation.
	 */
	return tevent_context_push_use(evg->run_ev);
}

static void smb_vfs_ev_glue_pop_use(const struct smb_vfs_ev_glue *evg)
{
	if (evg->run_ev == evg->return_ev) {
		/*
		 * smb_vfs_ev_glue_push_use() didn't
		 * change the impersonation environment.
		 */
		return;
	}

	/*
	 * undo the impersonation
	 */
	tevent_context_pop_use(evg->run_ev);
}

int smb_vfs_call_connect(struct vfs_handle_struct *handle,
			 const char *service, const char *user)
{
	VFS_FIND(connect);
	return handle->fns->connect_fn(handle, service, user);
}

void smb_vfs_call_disconnect(struct vfs_handle_struct *handle)
{
	VFS_FIND(disconnect);
	handle->fns->disconnect_fn(handle);
}

uint64_t smb_vfs_call_disk_free(struct vfs_handle_struct *handle,
				const struct smb_filename *smb_fname,
				uint64_t *bsize,
				uint64_t *dfree,
				uint64_t *dsize)
{
	VFS_FIND(disk_free);
	return handle->fns->disk_free_fn(handle, smb_fname,
			bsize, dfree, dsize);
}

int smb_vfs_call_get_quota(struct vfs_handle_struct *handle,
				const struct smb_filename *smb_fname,
				enum SMB_QUOTA_TYPE qtype,
				unid_t id,
				SMB_DISK_QUOTA *qt)
{
	VFS_FIND(get_quota);
	return handle->fns->get_quota_fn(handle, smb_fname, qtype, id, qt);
}

int smb_vfs_call_set_quota(struct vfs_handle_struct *handle,
			   enum SMB_QUOTA_TYPE qtype, unid_t id,
			   SMB_DISK_QUOTA *qt)
{
	VFS_FIND(set_quota);
	return handle->fns->set_quota_fn(handle, qtype, id, qt);
}

int smb_vfs_call_get_shadow_copy_data(struct vfs_handle_struct *handle,
				      struct files_struct *fsp,
				      struct shadow_copy_data *shadow_copy_data,
				      bool labels)
{
	VFS_FIND(get_shadow_copy_data);
	return handle->fns->get_shadow_copy_data_fn(handle, fsp, 
						    shadow_copy_data,
						    labels);
}
int smb_vfs_call_statvfs(struct vfs_handle_struct *handle,
			const struct smb_filename *smb_fname,
			struct vfs_statvfs_struct *statbuf)
{
	VFS_FIND(statvfs);
	return handle->fns->statvfs_fn(handle, smb_fname, statbuf);
}

uint32_t smb_vfs_call_fs_capabilities(struct vfs_handle_struct *handle,
			enum timestamp_set_resolution *p_ts_res)
{
	VFS_FIND(fs_capabilities);
	return handle->fns->fs_capabilities_fn(handle, p_ts_res);
}

NTSTATUS smb_vfs_call_get_dfs_referrals(struct vfs_handle_struct *handle,
					struct dfs_GetDFSReferral *r)
{
	VFS_FIND(get_dfs_referrals);
	return handle->fns->get_dfs_referrals_fn(handle, r);
}

DIR *smb_vfs_call_opendir(struct vfs_handle_struct *handle,
					const struct smb_filename *smb_fname,
					const char *mask,
					uint32_t attributes)
{
	VFS_FIND(opendir);
	return handle->fns->opendir_fn(handle, smb_fname, mask, attributes);
}

DIR *smb_vfs_call_fdopendir(struct vfs_handle_struct *handle,
					struct files_struct *fsp,
					const char *mask,
					uint32_t attributes)
{
	VFS_FIND(fdopendir);
	return handle->fns->fdopendir_fn(handle, fsp, mask, attributes);
}

struct dirent *smb_vfs_call_readdir(struct vfs_handle_struct *handle,
					      DIR *dirp,
					      SMB_STRUCT_STAT *sbuf)
{
	VFS_FIND(readdir);
	return handle->fns->readdir_fn(handle, dirp, sbuf);
}

void smb_vfs_call_seekdir(struct vfs_handle_struct *handle,
			  DIR *dirp, long offset)
{
	VFS_FIND(seekdir);
	handle->fns->seekdir_fn(handle, dirp, offset);
}

long smb_vfs_call_telldir(struct vfs_handle_struct *handle,
			  DIR *dirp)
{
	VFS_FIND(telldir);
	return handle->fns->telldir_fn(handle, dirp);
}

void smb_vfs_call_rewind_dir(struct vfs_handle_struct *handle,
			     DIR *dirp)
{
	VFS_FIND(rewind_dir);
	handle->fns->rewind_dir_fn(handle, dirp);
}

int smb_vfs_call_mkdir(struct vfs_handle_struct *handle,
			const struct smb_filename *smb_fname,
			mode_t mode)
{
	VFS_FIND(mkdir);
	return handle->fns->mkdir_fn(handle, smb_fname, mode);
}

int smb_vfs_call_rmdir(struct vfs_handle_struct *handle,
			const struct smb_filename *smb_fname)
{
	VFS_FIND(rmdir);
	return handle->fns->rmdir_fn(handle, smb_fname);
}

int smb_vfs_call_closedir(struct vfs_handle_struct *handle,
			  DIR *dir)
{
	VFS_FIND(closedir);
	return handle->fns->closedir_fn(handle, dir);
}

int smb_vfs_call_open(struct vfs_handle_struct *handle,
		      struct smb_filename *smb_fname, struct files_struct *fsp,
		      int flags, mode_t mode)
{
	VFS_FIND(open);
	return handle->fns->open_fn(handle, smb_fname, fsp, flags, mode);
}

NTSTATUS smb_vfs_call_create_file(struct vfs_handle_struct *handle,
				  struct smb_request *req,
				  uint16_t root_dir_fid,
				  struct smb_filename *smb_fname,
				  uint32_t access_mask,
				  uint32_t share_access,
				  uint32_t create_disposition,
				  uint32_t create_options,
				  uint32_t file_attributes,
				  uint32_t oplock_request,
				  struct smb2_lease *lease,
				  uint64_t allocation_size,
				  uint32_t private_flags,
				  struct security_descriptor *sd,
				  struct ea_list *ea_list,
				  files_struct **result,
				  int *pinfo,
				  const struct smb2_create_blobs *in_context_blobs,
				  struct smb2_create_blobs *out_context_blobs)
{
	VFS_FIND(create_file);
	return handle->fns->create_file_fn(
		handle, req, root_dir_fid, smb_fname, access_mask,
		share_access, create_disposition, create_options,
		file_attributes, oplock_request, lease, allocation_size,
		private_flags, sd, ea_list,
		result, pinfo, in_context_blobs, out_context_blobs);
}

int smb_vfs_call_close(struct vfs_handle_struct *handle,
		       struct files_struct *fsp)
{
	VFS_FIND(close);
	return handle->fns->close_fn(handle, fsp);
}

ssize_t smb_vfs_call_pread(struct vfs_handle_struct *handle,
			   struct files_struct *fsp, void *data, size_t n,
			   off_t offset)
{
	VFS_FIND(pread);
	return handle->fns->pread_fn(handle, fsp, data, n, offset);
}

struct smb_vfs_call_pread_state {
	ssize_t (*recv_fn)(struct tevent_req *req, struct vfs_aio_state *vfs_aio_state);
	ssize_t retval;
	struct vfs_aio_state vfs_aio_state;
};

static void smb_vfs_call_pread_done(struct tevent_req *subreq);

struct tevent_req *smb_vfs_call_pread_send(struct vfs_handle_struct *handle,
					   TALLOC_CTX *mem_ctx,
					   struct tevent_context *ev,
					   struct files_struct *fsp,
					   void *data,
					   size_t n, off_t offset)
{
	struct tevent_req *req, *subreq;
	struct smb_vfs_call_pread_state *state;

	req = tevent_req_create(mem_ctx, &state,
				struct smb_vfs_call_pread_state);
	if (req == NULL) {
		return NULL;
	}
	VFS_FIND(pread_send);
	state->recv_fn = handle->fns->pread_recv_fn;

	subreq = handle->fns->pread_send_fn(handle, state, ev, fsp, data, n,
					    offset);
	if (tevent_req_nomem(subreq, req)) {
		return tevent_req_post(req, ev);
	}
	tevent_req_set_callback(subreq, smb_vfs_call_pread_done, req);
	return req;
}

static void smb_vfs_call_pread_done(struct tevent_req *subreq)
{
	struct tevent_req *req = tevent_req_callback_data(
		subreq, struct tevent_req);
	struct smb_vfs_call_pread_state *state = tevent_req_data(
		req, struct smb_vfs_call_pread_state);

	state->retval = state->recv_fn(subreq, &state->vfs_aio_state);
	TALLOC_FREE(subreq);
	if (state->retval == -1) {
		tevent_req_error(req, state->vfs_aio_state.error);
		return;
	}
	tevent_req_done(req);
}

ssize_t SMB_VFS_PREAD_RECV(struct tevent_req *req,
			   struct vfs_aio_state *vfs_aio_state)
{
	struct smb_vfs_call_pread_state *state = tevent_req_data(
		req, struct smb_vfs_call_pread_state);
	ssize_t retval;

	if (tevent_req_is_unix_error(req, &vfs_aio_state->error)) {
		tevent_req_received(req);
		return -1;
	}
	*vfs_aio_state = state->vfs_aio_state;
	retval = state->retval;
	tevent_req_received(req);
	return retval;
}

ssize_t smb_vfs_call_pwrite(struct vfs_handle_struct *handle,
			    struct files_struct *fsp, const void *data,
			    size_t n, off_t offset)
{
	VFS_FIND(pwrite);
	return handle->fns->pwrite_fn(handle, fsp, data, n, offset);
}

struct smb_vfs_call_pwrite_state {
	ssize_t (*recv_fn)(struct tevent_req *req, struct vfs_aio_state *vfs_aio_state);
	ssize_t retval;
	struct vfs_aio_state vfs_aio_state;
};

static void smb_vfs_call_pwrite_done(struct tevent_req *subreq);

struct tevent_req *smb_vfs_call_pwrite_send(struct vfs_handle_struct *handle,
					    TALLOC_CTX *mem_ctx,
					    struct tevent_context *ev,
					    struct files_struct *fsp,
					    const void *data,
					    size_t n, off_t offset)
{
	struct tevent_req *req, *subreq;
	struct smb_vfs_call_pwrite_state *state;

	req = tevent_req_create(mem_ctx, &state,
				struct smb_vfs_call_pwrite_state);
	if (req == NULL) {
		return NULL;
	}
	VFS_FIND(pwrite_send);
	state->recv_fn = handle->fns->pwrite_recv_fn;

	subreq = handle->fns->pwrite_send_fn(handle, state, ev, fsp, data, n,
					     offset);
	if (tevent_req_nomem(subreq, req)) {
		return tevent_req_post(req, ev);
	}
	tevent_req_set_callback(subreq, smb_vfs_call_pwrite_done, req);
	return req;
}

static void smb_vfs_call_pwrite_done(struct tevent_req *subreq)
{
	struct tevent_req *req = tevent_req_callback_data(
		subreq, struct tevent_req);
	struct smb_vfs_call_pwrite_state *state = tevent_req_data(
		req, struct smb_vfs_call_pwrite_state);

	state->retval = state->recv_fn(subreq, &state->vfs_aio_state);
	TALLOC_FREE(subreq);
	if (state->retval == -1) {
		tevent_req_error(req, state->vfs_aio_state.error);
		return;
	}
	tevent_req_done(req);
}

ssize_t SMB_VFS_PWRITE_RECV(struct tevent_req *req,
			    struct vfs_aio_state *vfs_aio_state)
{
	struct smb_vfs_call_pwrite_state *state = tevent_req_data(
		req, struct smb_vfs_call_pwrite_state);
	ssize_t retval;

	if (tevent_req_is_unix_error(req, &vfs_aio_state->error)) {
		tevent_req_received(req);
		return -1;
	}
	*vfs_aio_state = state->vfs_aio_state;
	retval = state->retval;
	tevent_req_received(req);
	return retval;
}

off_t smb_vfs_call_lseek(struct vfs_handle_struct *handle,
			     struct files_struct *fsp, off_t offset,
			     int whence)
{
	VFS_FIND(lseek);
	return handle->fns->lseek_fn(handle, fsp, offset, whence);
}

ssize_t smb_vfs_call_sendfile(struct vfs_handle_struct *handle, int tofd,
			      files_struct *fromfsp, const DATA_BLOB *header,
			      off_t offset, size_t count)
{
	VFS_FIND(sendfile);
	return handle->fns->sendfile_fn(handle, tofd, fromfsp, header, offset,
					count);
}

ssize_t smb_vfs_call_recvfile(struct vfs_handle_struct *handle, int fromfd,
			      files_struct *tofsp, off_t offset,
			      size_t count)
{
	VFS_FIND(recvfile);
	return handle->fns->recvfile_fn(handle, fromfd, tofsp, offset, count);
}

int smb_vfs_call_rename(struct vfs_handle_struct *handle,
			const struct smb_filename *smb_fname_src,
			const struct smb_filename *smb_fname_dst)
{
	VFS_FIND(rename);
	return handle->fns->rename_fn(handle, smb_fname_src, smb_fname_dst);
}

struct smb_vfs_call_fsync_state {
	int (*recv_fn)(struct tevent_req *req, struct vfs_aio_state *vfs_aio_state);
	int retval;
	struct vfs_aio_state vfs_aio_state;
};

static void smb_vfs_call_fsync_done(struct tevent_req *subreq);

struct tevent_req *smb_vfs_call_fsync_send(struct vfs_handle_struct *handle,
					   TALLOC_CTX *mem_ctx,
					   struct tevent_context *ev,
					   struct files_struct *fsp)
{
	struct tevent_req *req, *subreq;
	struct smb_vfs_call_fsync_state *state;

	req = tevent_req_create(mem_ctx, &state,
				struct smb_vfs_call_fsync_state);
	if (req == NULL) {
		return NULL;
	}
	VFS_FIND(fsync_send);
	state->recv_fn = handle->fns->fsync_recv_fn;

	subreq = handle->fns->fsync_send_fn(handle, state, ev, fsp);
	if (tevent_req_nomem(subreq, req)) {
		return tevent_req_post(req, ev);
	}
	tevent_req_set_callback(subreq, smb_vfs_call_fsync_done, req);
	return req;
}

static void smb_vfs_call_fsync_done(struct tevent_req *subreq)
{
	struct tevent_req *req = tevent_req_callback_data(
		subreq, struct tevent_req);
	struct smb_vfs_call_fsync_state *state = tevent_req_data(
		req, struct smb_vfs_call_fsync_state);

	state->retval = state->recv_fn(subreq, &state->vfs_aio_state);
	TALLOC_FREE(subreq);
	if (state->retval == -1) {
		tevent_req_error(req, state->vfs_aio_state.error);
		return;
	}
	tevent_req_done(req);
}

int SMB_VFS_FSYNC_RECV(struct tevent_req *req, struct vfs_aio_state *vfs_aio_state)
{
	struct smb_vfs_call_fsync_state *state = tevent_req_data(
		req, struct smb_vfs_call_fsync_state);
	ssize_t retval;

	if (tevent_req_is_unix_error(req, &vfs_aio_state->error)) {
		tevent_req_received(req);
		return -1;
	}
	*vfs_aio_state = state->vfs_aio_state;
	retval = state->retval;
	tevent_req_received(req);
	return retval;
}

/*
 * Synchronous version of fsync, built from backend
 * async VFS primitives. Uses a temporary sub-event
 * context (NOT NESTED).
 */

int smb_vfs_fsync_sync(files_struct *fsp)
{
	TALLOC_CTX *frame = talloc_stackframe();
	struct tevent_req *req = NULL;
	struct vfs_aio_state aio_state = { 0 };
	int ret = -1;
	bool ok;
	struct tevent_context *ev = samba_tevent_context_init(frame);

	if (ev == NULL) {
		goto out;
	}

	req = SMB_VFS_FSYNC_SEND(talloc_tos(), ev, fsp);
	if (req == NULL) {
		goto out;
	}

	ok = tevent_req_poll(req, ev);
	if (!ok) {
		goto out;
	}

	ret = SMB_VFS_FSYNC_RECV(req, &aio_state);

  out:

	TALLOC_FREE(frame);
	if (aio_state.error != 0) {
		errno = aio_state.error;
	}
	return ret;
}

int smb_vfs_call_stat(struct vfs_handle_struct *handle,
		      struct smb_filename *smb_fname)
{
	VFS_FIND(stat);
	return handle->fns->stat_fn(handle, smb_fname);
}

int smb_vfs_call_fstat(struct vfs_handle_struct *handle,
		       struct files_struct *fsp, SMB_STRUCT_STAT *sbuf)
{
	VFS_FIND(fstat);
	return handle->fns->fstat_fn(handle, fsp, sbuf);
}

int smb_vfs_call_lstat(struct vfs_handle_struct *handle,
		       struct smb_filename *smb_filename)
{
	VFS_FIND(lstat);
	return handle->fns->lstat_fn(handle, smb_filename);
}

uint64_t smb_vfs_call_get_alloc_size(struct vfs_handle_struct *handle,
				     struct files_struct *fsp,
				     const SMB_STRUCT_STAT *sbuf)
{
	VFS_FIND(get_alloc_size);
	return handle->fns->get_alloc_size_fn(handle, fsp, sbuf);
}

int smb_vfs_call_unlink(struct vfs_handle_struct *handle,
			const struct smb_filename *smb_fname)
{
	VFS_FIND(unlink);
	return handle->fns->unlink_fn(handle, smb_fname);
}

int smb_vfs_call_chmod(struct vfs_handle_struct *handle,
			const struct smb_filename *smb_fname,
			mode_t mode)
{
	VFS_FIND(chmod);
	return handle->fns->chmod_fn(handle, smb_fname, mode);
}

int smb_vfs_call_fchmod(struct vfs_handle_struct *handle,
			struct files_struct *fsp, mode_t mode)
{
	VFS_FIND(fchmod);
	return handle->fns->fchmod_fn(handle, fsp, mode);
}

int smb_vfs_call_chown(struct vfs_handle_struct *handle,
			const struct smb_filename *smb_fname,
			uid_t uid,
			gid_t gid)
{
	VFS_FIND(chown);
	return handle->fns->chown_fn(handle, smb_fname, uid, gid);
}

int smb_vfs_call_fchown(struct vfs_handle_struct *handle,
			struct files_struct *fsp, uid_t uid, gid_t gid)
{
	VFS_FIND(fchown);
	return handle->fns->fchown_fn(handle, fsp, uid, gid);
}

int smb_vfs_call_lchown(struct vfs_handle_struct *handle,
			const struct smb_filename *smb_fname,
			uid_t uid,
			gid_t gid)
{
	VFS_FIND(lchown);
	return handle->fns->lchown_fn(handle, smb_fname, uid, gid);
}

NTSTATUS vfs_chown_fsp(files_struct *fsp, uid_t uid, gid_t gid)
{
	int ret;
	bool as_root = false;
	NTSTATUS status;

	if (fsp->fh->fd != -1) {
		/* Try fchown. */
		ret = SMB_VFS_FCHOWN(fsp, uid, gid);
		if (ret == 0) {
			return NT_STATUS_OK;
		}
		if (ret == -1 && errno != ENOSYS) {
			return map_nt_error_from_unix(errno);
		}
	}

	as_root = (geteuid() == 0);

	if (as_root) {
		/*
		 * We are being asked to chown as root. Make
		 * sure we chdir() into the path to pin it,
		 * and always act using lchown to ensure we
		 * don't deref any symbolic links.
		 */
		char *parent_dir = NULL;
		const char *final_component = NULL;
		struct smb_filename *local_smb_fname = NULL;
		struct smb_filename parent_dir_fname = {0};
		struct smb_filename *saved_dir_fname = NULL;

		saved_dir_fname = vfs_GetWd(talloc_tos(),fsp->conn);
		if (!saved_dir_fname) {
			status = map_nt_error_from_unix(errno);
			DEBUG(0,("vfs_chown_fsp: failed to get "
				"current working directory. Error was %s\n",
				strerror(errno)));
			return status;
		}

		if (!parent_dirname(talloc_tos(),
				fsp->fsp_name->base_name,
				&parent_dir,
				&final_component)) {
			return NT_STATUS_NO_MEMORY;
		}

		parent_dir_fname = (struct smb_filename) {
			.base_name = parent_dir,
			.flags = fsp->fsp_name->flags
		};

		/* cd into the parent dir to pin it. */
		ret = vfs_ChDir(fsp->conn, &parent_dir_fname);
		if (ret == -1) {
			return map_nt_error_from_unix(errno);
		}

		local_smb_fname = synthetic_smb_fname(talloc_tos(),
					final_component,
					NULL,
					NULL,
					fsp->fsp_name->flags);
		if (local_smb_fname == NULL) {
			status = NT_STATUS_NO_MEMORY;
			goto out;
		}

		/* Must use lstat here. */
		ret = SMB_VFS_LSTAT(fsp->conn, local_smb_fname);
		if (ret == -1) {
			status = map_nt_error_from_unix(errno);
			goto out;
		}

		/* Ensure it matches the fsp stat. */
		if (!check_same_stat(&local_smb_fname->st,
				&fsp->fsp_name->st)) {
                        status = NT_STATUS_ACCESS_DENIED;
			goto out;
                }

		ret = SMB_VFS_LCHOWN(fsp->conn,
			local_smb_fname,
			uid, gid);

		if (ret == 0) {
			status = NT_STATUS_OK;
		} else {
			status = map_nt_error_from_unix(errno);
		}

  out:

		vfs_ChDir(fsp->conn, saved_dir_fname);
		TALLOC_FREE(local_smb_fname);
		TALLOC_FREE(saved_dir_fname);
		TALLOC_FREE(parent_dir);

		return status;
	}

	if (fsp->posix_flags & FSP_POSIX_FLAGS_OPEN) {
		ret = SMB_VFS_LCHOWN(fsp->conn,
			fsp->fsp_name,
			uid, gid);
	} else {
		ret = SMB_VFS_CHOWN(fsp->conn,
			fsp->fsp_name,
			uid, gid);
	}

	if (ret == 0) {
		status = NT_STATUS_OK;
	} else {
		status = map_nt_error_from_unix(errno);
	}
	return status;
}

int smb_vfs_call_chdir(struct vfs_handle_struct *handle,
			const struct smb_filename *smb_fname)
{
	VFS_FIND(chdir);
	return handle->fns->chdir_fn(handle, smb_fname);
}

struct smb_filename *smb_vfs_call_getwd(struct vfs_handle_struct *handle,
				TALLOC_CTX *ctx)
{
	VFS_FIND(getwd);
	return handle->fns->getwd_fn(handle, ctx);
}

int smb_vfs_call_ntimes(struct vfs_handle_struct *handle,
			const struct smb_filename *smb_fname,
			struct smb_file_time *ft)
{
	VFS_FIND(ntimes);
	return handle->fns->ntimes_fn(handle, smb_fname, ft);
}

int smb_vfs_call_ftruncate(struct vfs_handle_struct *handle,
			   struct files_struct *fsp, off_t offset)
{
	VFS_FIND(ftruncate);
	return handle->fns->ftruncate_fn(handle, fsp, offset);
}

int smb_vfs_call_fallocate(struct vfs_handle_struct *handle,
			   struct files_struct *fsp,
			   uint32_t mode,
			   off_t offset,
			   off_t len)
{
	VFS_FIND(fallocate);
	return handle->fns->fallocate_fn(handle, fsp, mode, offset, len);
}

int smb_vfs_call_kernel_flock(struct vfs_handle_struct *handle,
			      struct files_struct *fsp, uint32_t share_mode,
			      uint32_t access_mask)
{
	VFS_FIND(kernel_flock);
	return handle->fns->kernel_flock_fn(handle, fsp, share_mode,
					 access_mask);
}

int smb_vfs_call_linux_setlease(struct vfs_handle_struct *handle,
				struct files_struct *fsp, int leasetype)
{
	VFS_FIND(linux_setlease);
	return handle->fns->linux_setlease_fn(handle, fsp, leasetype);
}

int smb_vfs_call_symlink(struct vfs_handle_struct *handle,
			const char *link_target,
			const struct smb_filename *new_smb_fname)
{
	VFS_FIND(symlink);
	return handle->fns->symlink_fn(handle, link_target, new_smb_fname);
}

int smb_vfs_call_readlink(struct vfs_handle_struct *handle,
			const struct smb_filename *smb_fname,
			char *buf,
			size_t bufsiz)
{
	VFS_FIND(readlink);
	return handle->fns->readlink_fn(handle, smb_fname, buf, bufsiz);
}

int smb_vfs_call_link(struct vfs_handle_struct *handle,
			const struct smb_filename *old_smb_fname,
			const struct smb_filename *new_smb_fname)
{
	VFS_FIND(link);
	return handle->fns->link_fn(handle, old_smb_fname, new_smb_fname);
}

int smb_vfs_call_mknod(struct vfs_handle_struct *handle,
			const struct smb_filename *smb_fname,
			mode_t mode,
			SMB_DEV_T dev)
{
	VFS_FIND(mknod);
	return handle->fns->mknod_fn(handle, smb_fname, mode, dev);
}

struct smb_filename *smb_vfs_call_realpath(struct vfs_handle_struct *handle,
			TALLOC_CTX *ctx,
			const struct smb_filename *smb_fname)
{
	VFS_FIND(realpath);
	return handle->fns->realpath_fn(handle, ctx, smb_fname);
}

int smb_vfs_call_chflags(struct vfs_handle_struct *handle,
			const struct smb_filename *smb_fname,
			unsigned int flags)
{
	VFS_FIND(chflags);
	return handle->fns->chflags_fn(handle, smb_fname, flags);
}

struct file_id smb_vfs_call_file_id_create(struct vfs_handle_struct *handle,
					   const SMB_STRUCT_STAT *sbuf)
{
	VFS_FIND(file_id_create);
	return handle->fns->file_id_create_fn(handle, sbuf);
}

NTSTATUS smb_vfs_call_streaminfo(struct vfs_handle_struct *handle,
				 struct files_struct *fsp,
				 const struct smb_filename *smb_fname,
				 TALLOC_CTX *mem_ctx,
				 unsigned int *num_streams,
				 struct stream_struct **streams)
{
	VFS_FIND(streaminfo);
	return handle->fns->streaminfo_fn(handle, fsp, smb_fname, mem_ctx,
					  num_streams, streams);
}

int smb_vfs_call_get_real_filename(struct vfs_handle_struct *handle,
				   const char *path, const char *name,
				   TALLOC_CTX *mem_ctx, char **found_name)
{
	VFS_FIND(get_real_filename);
	return handle->fns->get_real_filename_fn(handle, path, name, mem_ctx,
						 found_name);
}

const char *smb_vfs_call_connectpath(struct vfs_handle_struct *handle,
				 const struct smb_filename *smb_fname)
{
	VFS_FIND(connectpath);
	return handle->fns->connectpath_fn(handle, smb_fname);
}

bool smb_vfs_call_strict_lock_check(struct vfs_handle_struct *handle,
				    struct files_struct *fsp,
				    struct lock_struct *plock)
{
	VFS_FIND(strict_lock_check);
	return handle->fns->strict_lock_check_fn(handle, fsp, plock);
}

NTSTATUS smb_vfs_call_translate_name(struct vfs_handle_struct *handle,
				     const char *name,
				     enum vfs_translate_direction direction,
				     TALLOC_CTX *mem_ctx,
				     char **mapped_name)
{
	VFS_FIND(translate_name);
	return handle->fns->translate_name_fn(handle, name, direction, mem_ctx,
					      mapped_name);
}

NTSTATUS smb_vfs_call_fsctl(struct vfs_handle_struct *handle,
			    struct files_struct *fsp,
			    TALLOC_CTX *ctx,
			    uint32_t function,
			    uint16_t req_flags,
			    const uint8_t *in_data,
			    uint32_t in_len,
			    uint8_t **out_data,
			    uint32_t max_out_len,
			    uint32_t *out_len)
{
	VFS_FIND(fsctl);
	return handle->fns->fsctl_fn(handle, fsp, ctx, function, req_flags,
				     in_data, in_len, out_data, max_out_len,
				     out_len);
}

NTSTATUS smb_vfs_call_get_dos_attributes(struct vfs_handle_struct *handle,
					 struct smb_filename *smb_fname,
					 uint32_t *dosmode)
{
	VFS_FIND(get_dos_attributes);
	return handle->fns->get_dos_attributes_fn(handle, smb_fname, dosmode);
}

NTSTATUS smb_vfs_call_fget_dos_attributes(struct vfs_handle_struct *handle,
					  struct files_struct *fsp,
					  uint32_t *dosmode)
{
	VFS_FIND(fget_dos_attributes);
	return handle->fns->fget_dos_attributes_fn(handle, fsp, dosmode);
}

NTSTATUS smb_vfs_call_set_dos_attributes(struct vfs_handle_struct *handle,
					 const struct smb_filename *smb_fname,
					 uint32_t dosmode)
{
	VFS_FIND(set_dos_attributes);
	return handle->fns->set_dos_attributes_fn(handle, smb_fname, dosmode);
}

NTSTATUS smb_vfs_call_fset_dos_attributes(struct vfs_handle_struct *handle,
					  struct files_struct *fsp,
					  uint32_t dosmode)
{
	VFS_FIND(set_dos_attributes);
	return handle->fns->fset_dos_attributes_fn(handle, fsp, dosmode);
}

struct tevent_req *smb_vfs_call_offload_read_send(TALLOC_CTX *mem_ctx,
						  struct tevent_context *ev,
						  struct vfs_handle_struct *handle,
						  struct files_struct *fsp,
						  uint32_t fsctl,
						  uint32_t ttl,
						  off_t offset,
						  size_t to_copy)
{
	VFS_FIND(offload_read_send);
	return handle->fns->offload_read_send_fn(mem_ctx, ev, handle,
						 fsp, fsctl,
						 ttl, offset, to_copy);
}

NTSTATUS smb_vfs_call_offload_read_recv(struct tevent_req *req,
					struct vfs_handle_struct *handle,
					TALLOC_CTX *mem_ctx,
					DATA_BLOB *token_blob)
{
	VFS_FIND(offload_read_recv);
	return handle->fns->offload_read_recv_fn(req, handle, mem_ctx, token_blob);
}

struct tevent_req *smb_vfs_call_offload_write_send(struct vfs_handle_struct *handle,
						   TALLOC_CTX *mem_ctx,
						   struct tevent_context *ev,
						   uint32_t fsctl,
						   DATA_BLOB *token,
						   off_t transfer_offset,
						   struct files_struct *dest_fsp,
						   off_t dest_off,
						   off_t num)
{
	VFS_FIND(offload_write_send);
	return handle->fns->offload_write_send_fn(handle, mem_ctx, ev, fsctl,
					       token, transfer_offset,
					       dest_fsp, dest_off, num);
}

NTSTATUS smb_vfs_call_offload_write_recv(struct vfs_handle_struct *handle,
					 struct tevent_req *req,
					 off_t *copied)
{
	VFS_FIND(offload_write_recv);
	return handle->fns->offload_write_recv_fn(handle, req, copied);
}

struct smb_vfs_call_get_dos_attributes_state {
	NTSTATUS (*recv_fn)(struct tevent_req *req,
			    struct vfs_aio_state *aio_state,
			    uint32_t *dosmode);
	struct vfs_aio_state aio_state;
	uint32_t dos_attributes;
};

static void smb_vfs_call_get_dos_attributes_done(struct tevent_req *subreq);

struct tevent_req *smb_vfs_call_get_dos_attributes_send(
			TALLOC_CTX *mem_ctx,
			const struct smb_vfs_ev_glue *evg,
			struct vfs_handle_struct *handle,
			files_struct *dir_fsp,
			struct smb_filename *smb_fname)
{
	struct tevent_req *req = NULL;
	struct smb_vfs_call_get_dos_attributes_state *state = NULL;
	struct tevent_req *subreq = NULL;
	bool ok;

	req = tevent_req_create(mem_ctx, &state,
				struct smb_vfs_call_get_dos_attributes_state);
	if (req == NULL) {
		return NULL;
	}

	VFS_FIND(get_dos_attributes_send);
	state->recv_fn = handle->fns->get_dos_attributes_recv_fn;

	ok = smb_vfs_ev_glue_push_use(evg, req);
	if (!ok) {
		tevent_req_error(req, EIO);
		return tevent_req_post(req, evg->return_ev);
	}

	subreq = handle->fns->get_dos_attributes_send_fn(mem_ctx,
							 evg->next_glue,
							 handle,
							 dir_fsp,
							 smb_fname);
	smb_vfs_ev_glue_pop_use(evg);

	if (tevent_req_nomem(subreq, req)) {
		return tevent_req_post(req, evg->return_ev);
	}
	tevent_req_set_callback(subreq,
				smb_vfs_call_get_dos_attributes_done,
				req);

	return req;
}

static void smb_vfs_call_get_dos_attributes_done(struct tevent_req *subreq)
{
	struct tevent_req *req =
		tevent_req_callback_data(subreq,
		struct tevent_req);
	struct smb_vfs_call_get_dos_attributes_state *state =
		tevent_req_data(req,
		struct smb_vfs_call_get_dos_attributes_state);
	NTSTATUS status;

	status = state->recv_fn(subreq,
				&state->aio_state,
				&state->dos_attributes);
	TALLOC_FREE(subreq);
	if (tevent_req_nterror(req, status)) {
		return;
	}

	tevent_req_done(req);
}

NTSTATUS smb_vfs_call_get_dos_attributes_recv(
		struct tevent_req *req,
		struct vfs_aio_state *aio_state,
		uint32_t *dos_attributes)
{
	struct smb_vfs_call_get_dos_attributes_state *state =
		tevent_req_data(req,
		struct smb_vfs_call_get_dos_attributes_state);
	NTSTATUS status;

	if (tevent_req_is_nterror(req, &status)) {
		tevent_req_received(req);
		return status;
	}

	*aio_state = state->aio_state;
	*dos_attributes = state->dos_attributes;
	tevent_req_received(req);
	return NT_STATUS_OK;
}

NTSTATUS smb_vfs_call_get_compression(vfs_handle_struct *handle,
				      TALLOC_CTX *mem_ctx,
				      struct files_struct *fsp,
				      struct smb_filename *smb_fname,
				      uint16_t *_compression_fmt)
{
	VFS_FIND(get_compression);
	return handle->fns->get_compression_fn(handle, mem_ctx, fsp, smb_fname,
					       _compression_fmt);
}

NTSTATUS smb_vfs_call_set_compression(vfs_handle_struct *handle,
				      TALLOC_CTX *mem_ctx,
				      struct files_struct *fsp,
				      uint16_t compression_fmt)
{
	VFS_FIND(set_compression);
	return handle->fns->set_compression_fn(handle, mem_ctx, fsp,
					       compression_fmt);
}

NTSTATUS smb_vfs_call_snap_check_path(vfs_handle_struct *handle,
				      TALLOC_CTX *mem_ctx,
				      const char *service_path,
				      char **base_volume)
{
	VFS_FIND(snap_check_path);
	return handle->fns->snap_check_path_fn(handle, mem_ctx, service_path,
					       base_volume);
}

NTSTATUS smb_vfs_call_snap_create(struct vfs_handle_struct *handle,
				  TALLOC_CTX *mem_ctx,
				  const char *base_volume,
				  time_t *tstamp,
				  bool rw,
				  char **base_path,
				  char **snap_path)
{
	VFS_FIND(snap_create);
	return handle->fns->snap_create_fn(handle, mem_ctx, base_volume, tstamp,
					   rw, base_path, snap_path);
}

NTSTATUS smb_vfs_call_snap_delete(struct vfs_handle_struct *handle,
				  TALLOC_CTX *mem_ctx,
				  char *base_path,
				  char *snap_path)
{
	VFS_FIND(snap_delete);
	return handle->fns->snap_delete_fn(handle, mem_ctx, base_path,
					   snap_path);
}

NTSTATUS smb_vfs_call_fget_nt_acl(struct vfs_handle_struct *handle,
				  struct files_struct *fsp,
				  uint32_t security_info,
				  TALLOC_CTX *mem_ctx,
				  struct security_descriptor **ppdesc)
{
	VFS_FIND(fget_nt_acl);
	return handle->fns->fget_nt_acl_fn(handle, fsp, security_info,
					   mem_ctx, ppdesc);
}

NTSTATUS smb_vfs_call_get_nt_acl(struct vfs_handle_struct *handle,
				 const struct smb_filename *smb_fname,
				 uint32_t security_info,
				 TALLOC_CTX *mem_ctx,
				 struct security_descriptor **ppdesc)
{
	VFS_FIND(get_nt_acl);
	return handle->fns->get_nt_acl_fn(handle,
				smb_fname,
				security_info,
				mem_ctx,
				ppdesc);
}

NTSTATUS smb_vfs_call_fset_nt_acl(struct vfs_handle_struct *handle,
				  struct files_struct *fsp,
				  uint32_t security_info_sent,
				  const struct security_descriptor *psd)
{
	VFS_FIND(fset_nt_acl);
	return handle->fns->fset_nt_acl_fn(handle, fsp, security_info_sent, 
					   psd);
}

NTSTATUS smb_vfs_call_audit_file(struct vfs_handle_struct *handle,
				 struct smb_filename *file,
				 struct security_acl *sacl,
				 uint32_t access_requested,
				 uint32_t access_denied)
{
	VFS_FIND(audit_file);
	return handle->fns->audit_file_fn(handle, 
					  file, 
					  sacl, 
					  access_requested, 
					  access_denied);
}

SMB_ACL_T smb_vfs_call_sys_acl_get_file(struct vfs_handle_struct *handle,
					const struct smb_filename *smb_fname,
					SMB_ACL_TYPE_T type,
					TALLOC_CTX *mem_ctx)
{
	VFS_FIND(sys_acl_get_file);
	return handle->fns->sys_acl_get_file_fn(handle, smb_fname, type, mem_ctx);
}

SMB_ACL_T smb_vfs_call_sys_acl_get_fd(struct vfs_handle_struct *handle,
				      struct files_struct *fsp,
				      TALLOC_CTX *mem_ctx)
{
	VFS_FIND(sys_acl_get_fd);
	return handle->fns->sys_acl_get_fd_fn(handle, fsp, mem_ctx);
}

int smb_vfs_call_sys_acl_blob_get_file(struct vfs_handle_struct *handle,
				const struct smb_filename *smb_fname,
				TALLOC_CTX *mem_ctx,
				char **blob_description,
				DATA_BLOB *blob)
{
	VFS_FIND(sys_acl_blob_get_file);
	return handle->fns->sys_acl_blob_get_file_fn(handle, smb_fname,
			mem_ctx, blob_description, blob);
}

int smb_vfs_call_sys_acl_blob_get_fd(struct vfs_handle_struct *handle,
				     struct files_struct *fsp,
				     TALLOC_CTX *mem_ctx, 
				     char **blob_description,
				     DATA_BLOB *blob)
{
	VFS_FIND(sys_acl_blob_get_fd);
	return handle->fns->sys_acl_blob_get_fd_fn(handle, fsp, mem_ctx, blob_description, blob);
}

int smb_vfs_call_sys_acl_set_file(struct vfs_handle_struct *handle,
				const struct smb_filename *smb_fname,
				SMB_ACL_TYPE_T acltype,
				SMB_ACL_T theacl)
{
	VFS_FIND(sys_acl_set_file);
	return handle->fns->sys_acl_set_file_fn(handle, smb_fname,
				acltype, theacl);
}

int smb_vfs_call_sys_acl_set_fd(struct vfs_handle_struct *handle,
				struct files_struct *fsp, SMB_ACL_T theacl)
{
	VFS_FIND(sys_acl_set_fd);
	return handle->fns->sys_acl_set_fd_fn(handle, fsp, theacl);
}

int smb_vfs_call_sys_acl_delete_def_file(struct vfs_handle_struct *handle,
				const struct smb_filename *smb_fname)
{
	VFS_FIND(sys_acl_delete_def_file);
	return handle->fns->sys_acl_delete_def_file_fn(handle, smb_fname);
}

ssize_t smb_vfs_call_getxattr(struct vfs_handle_struct *handle,
				const struct smb_filename *smb_fname,
				const char *name,
				void *value,
				size_t size)
{
	VFS_FIND(getxattr);
	return handle->fns->getxattr_fn(handle, smb_fname, name, value, size);
}


struct smb_vfs_call_getxattrat_state {
	ssize_t (*recv_fn)(struct tevent_req *req,
			   struct vfs_aio_state *aio_state,
			   TALLOC_CTX *mem_ctx,
			   uint8_t **xattr_value);
	ssize_t retval;
	uint8_t *xattr_value;
	struct vfs_aio_state aio_state;
};

static void smb_vfs_call_getxattrat_done(struct tevent_req *subreq);

struct tevent_req *smb_vfs_call_getxattrat_send(
			TALLOC_CTX *mem_ctx,
			const struct smb_vfs_ev_glue *evg,
			struct vfs_handle_struct *handle,
			files_struct *dir_fsp,
			const struct smb_filename *smb_fname,
			const char *xattr_name,
			size_t alloc_hint)
{
	struct tevent_req *req = NULL;
	struct smb_vfs_call_getxattrat_state *state = NULL;
	struct tevent_req *subreq = NULL;
	bool ok;

	req = tevent_req_create(mem_ctx, &state,
				struct smb_vfs_call_getxattrat_state);
	if (req == NULL) {
		return NULL;
	}

	VFS_FIND(getxattrat_send);
	state->recv_fn = handle->fns->getxattrat_recv_fn;

	ok = smb_vfs_ev_glue_push_use(evg, req);
	if (!ok) {
		tevent_req_error(req, EIO);
		return tevent_req_post(req, evg->return_ev);
	}

	subreq = handle->fns->getxattrat_send_fn(mem_ctx,
						 evg->next_glue,
						 handle,
						 dir_fsp,
						 smb_fname,
						 xattr_name,
						 alloc_hint);
	smb_vfs_ev_glue_pop_use(evg);

	if (tevent_req_nomem(subreq, req)) {
		return tevent_req_post(req, evg->return_ev);
	}
	tevent_req_set_callback(subreq, smb_vfs_call_getxattrat_done, req);
	return req;
}

static void smb_vfs_call_getxattrat_done(struct tevent_req *subreq)
{
	struct tevent_req *req = tevent_req_callback_data(
		subreq, struct tevent_req);
	struct smb_vfs_call_getxattrat_state *state = tevent_req_data(
		req, struct smb_vfs_call_getxattrat_state);

	state->retval = state->recv_fn(subreq,
				       &state->aio_state,
				       state,
				       &state->xattr_value);
	TALLOC_FREE(subreq);
	if (state->retval == -1) {
		tevent_req_error(req, state->aio_state.error);
		return;
	}

	tevent_req_done(req);
}

ssize_t smb_vfs_call_getxattrat_recv(struct tevent_req *req,
				     struct vfs_aio_state *aio_state,
				     TALLOC_CTX *mem_ctx,
				     uint8_t **xattr_value)
{
	struct smb_vfs_call_getxattrat_state *state = tevent_req_data(
		req, struct smb_vfs_call_getxattrat_state);
	size_t xattr_size;

	if (tevent_req_is_unix_error(req, &aio_state->error)) {
		tevent_req_received(req);
		return -1;
	}

	*aio_state = state->aio_state;
	xattr_size = state->retval;
	if (xattr_value != NULL) {
		*xattr_value = talloc_move(mem_ctx, &state->xattr_value);
	}

	tevent_req_received(req);
	return xattr_size;
}

ssize_t smb_vfs_call_fgetxattr(struct vfs_handle_struct *handle,
			       struct files_struct *fsp, const char *name,
			       void *value, size_t size)
{
	VFS_FIND(fgetxattr);
	return handle->fns->fgetxattr_fn(handle, fsp, name, value, size);
}

ssize_t smb_vfs_call_listxattr(struct vfs_handle_struct *handle,
				const struct smb_filename *smb_fname,
				char *list,
				size_t size)
{
	VFS_FIND(listxattr);
	return handle->fns->listxattr_fn(handle, smb_fname, list, size);
}

ssize_t smb_vfs_call_flistxattr(struct vfs_handle_struct *handle,
				struct files_struct *fsp, char *list,
				size_t size)
{
	VFS_FIND(flistxattr);
	return handle->fns->flistxattr_fn(handle, fsp, list, size);
}

int smb_vfs_call_removexattr(struct vfs_handle_struct *handle,
				const struct smb_filename *smb_fname,
				const char *name)
{
	VFS_FIND(removexattr);
	return handle->fns->removexattr_fn(handle, smb_fname, name);
}

int smb_vfs_call_fremovexattr(struct vfs_handle_struct *handle,
			      struct files_struct *fsp, const char *name)
{
	VFS_FIND(fremovexattr);
	return handle->fns->fremovexattr_fn(handle, fsp, name);
}

int smb_vfs_call_setxattr(struct vfs_handle_struct *handle,
			const struct smb_filename *smb_fname,
			const char *name,
			const void *value,
			size_t size,
			int flags)
{
	VFS_FIND(setxattr);
	return handle->fns->setxattr_fn(handle, smb_fname,
			name, value, size, flags);
}

int smb_vfs_call_fsetxattr(struct vfs_handle_struct *handle,
			   struct files_struct *fsp, const char *name,
			   const void *value, size_t size, int flags)
{
	VFS_FIND(fsetxattr);
	return handle->fns->fsetxattr_fn(handle, fsp, name, value, size, flags);
}

bool smb_vfs_call_aio_force(struct vfs_handle_struct *handle,
			    struct files_struct *fsp)
{
	VFS_FIND(aio_force);
	return handle->fns->aio_force_fn(handle, fsp);
}

NTSTATUS smb_vfs_call_durable_cookie(struct vfs_handle_struct *handle,
				     struct files_struct *fsp,
				     TALLOC_CTX *mem_ctx,
				     DATA_BLOB *cookie)
{
	VFS_FIND(durable_cookie);
	return handle->fns->durable_cookie_fn(handle, fsp, mem_ctx, cookie);
}

NTSTATUS smb_vfs_call_durable_disconnect(struct vfs_handle_struct *handle,
					 struct files_struct *fsp,
					 const DATA_BLOB old_cookie,
					 TALLOC_CTX *mem_ctx,
					 DATA_BLOB *new_cookie)
{
	VFS_FIND(durable_disconnect);
	return handle->fns->durable_disconnect_fn(handle, fsp, old_cookie,
					          mem_ctx, new_cookie);
}

NTSTATUS smb_vfs_call_durable_reconnect(struct vfs_handle_struct *handle,
					struct smb_request *smb1req,
					struct smbXsrv_open *op,
					const DATA_BLOB old_cookie,
					TALLOC_CTX *mem_ctx,
					struct files_struct **fsp,
					DATA_BLOB *new_cookie)
{
	VFS_FIND(durable_reconnect);
	return handle->fns->durable_reconnect_fn(handle, smb1req, op,
					         old_cookie, mem_ctx, fsp,
					         new_cookie);
}

NTSTATUS smb_vfs_call_readdir_attr(struct vfs_handle_struct *handle,
				   const struct smb_filename *fname,
				   TALLOC_CTX *mem_ctx,
				   struct readdir_attr_data **attr_data)
{
	VFS_FIND(readdir_attr);
	return handle->fns->readdir_attr_fn(handle, fname, mem_ctx, attr_data);
}