samba-mirror/source3/smbd/files.c

/* 
   Unix SMB/CIFS implementation.
   Files[] structure handling
   Copyright (C) Andrew Tridgell 1998

   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/>.
*/

#include "includes.h"
#include "smbd/smbd.h"
#include "smbd/globals.h"
#include "smbd/smbXsrv_open.h"
#include "libcli/security/security.h"
#include "util_tdb.h"
#include "lib/util/bitmap.h"

#define FILE_HANDLE_OFFSET 0x1000

static NTSTATUS fsp_attach_smb_fname(struct files_struct *fsp,
				     struct smb_filename **_smb_fname);

/**
 * create new fsp to be used for file_new or a durable handle reconnect
 */
NTSTATUS fsp_new(struct connection_struct *conn, TALLOC_CTX *mem_ctx,
		 files_struct **result)
{
	NTSTATUS status = NT_STATUS_NO_MEMORY;
	files_struct *fsp = NULL;
	struct smbd_server_connection *sconn = conn->sconn;

	fsp = talloc_zero(mem_ctx, struct files_struct);
	if (fsp == NULL) {
		goto fail;
	}

	/*
	 * This can't be a child of fsp because the file_handle can be ref'd
	 * when doing a dos/fcb open, which will then share the file_handle
	 * across multiple fsps.
	 */
	fsp->fh = fd_handle_create(mem_ctx);
	if (fsp->fh == NULL) {
		goto fail;
	}

	fsp->fsp_flags.use_ofd_locks = !lp_smbd_force_process_locks(SNUM(conn));
#ifndef HAVE_OFD_LOCKS
	fsp->fsp_flags.use_ofd_locks = false;
#endif

	fh_set_refcount(fsp->fh, 1);
	fsp_set_fd(fsp, -1);

	fsp->fnum = FNUM_FIELD_INVALID;
	fsp->conn = conn;
	fsp->close_write_time = make_omit_timespec();

	DLIST_ADD(sconn->files, fsp);
	sconn->num_files += 1;

	conn->num_files_open++;

	DBG_INFO("allocated files structure (%u used)\n",
		(unsigned int)sconn->num_files);

	*result = fsp;
	return NT_STATUS_OK;

fail:
	if (fsp != NULL) {
		TALLOC_FREE(fsp->fh);
	}
	TALLOC_FREE(fsp);

	return status;
}

void fsp_set_gen_id(files_struct *fsp)
{
	static uint64_t gen_id = 1;

	/*
	 * A billion of 64-bit increments per second gives us
	 * more than 500 years of runtime without wrap.
	 */
	gen_id++;
	fh_set_gen_id(fsp->fh, gen_id);
}

/****************************************************************************
 Find first available file slot.
****************************************************************************/

NTSTATUS fsp_bind_smb(struct files_struct *fsp, struct smb_request *req)
{
	struct smbXsrv_open *op = NULL;
	NTTIME now;
	NTSTATUS status;

	if (req == NULL) {
		DBG_DEBUG("INTERNAL_OPEN_ONLY, skipping smbXsrv_open\n");
		return NT_STATUS_OK;
	}

	now = timeval_to_nttime(&fsp->open_time);

	status = smbXsrv_open_create(req->xconn,
				     fsp->conn->session_info,
				     now,
				     &op);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}
	fsp->op = op;
	op->compat = fsp;
	fsp->fnum = op->local_id;

	fsp->mid = req->mid;
	req->chain_fsp = fsp;

	DBG_DEBUG("fsp [%s] mid [%" PRIu64"]\n",
		fsp_str_dbg(fsp), fsp->mid);

	return NT_STATUS_OK;
}

NTSTATUS file_new(struct smb_request *req, connection_struct *conn,
		  files_struct **result)
{
	struct smbd_server_connection *sconn = conn->sconn;
	files_struct *fsp;
	NTSTATUS status;

	status = fsp_new(conn, conn, &fsp);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	GetTimeOfDay(&fsp->open_time);

	status = fsp_bind_smb(fsp, req);
	if (!NT_STATUS_IS_OK(status)) {
		file_free(NULL, fsp);
		return status;
	}

	fsp_set_gen_id(fsp);

	/*
	 * Create an smb_filename with "" for the base_name.  There are very
	 * few NULL checks, so make sure it's initialized with something. to
	 * be safe until an audit can be done.
	 */
	fsp->fsp_name = synthetic_smb_fname(fsp,
					    "",
					    NULL,
					    NULL,
					    0,
					    0);
	if (fsp->fsp_name == NULL) {
		file_free(NULL, fsp);
		return NT_STATUS_NO_MEMORY;
	}

	DBG_INFO("new file %s\n", fsp_fnum_dbg(fsp));

	/* A new fsp invalidates the positive and
	  negative fsp_fi_cache as the new fsp is pushed
	  at the start of the list and we search from
	  a cache hit to the *end* of the list. */

	ZERO_STRUCT(sconn->fsp_fi_cache);

	*result = fsp;
	return NT_STATUS_OK;
}

NTSTATUS create_internal_fsp(connection_struct *conn,
			     const struct smb_filename *smb_fname,
			     struct files_struct **_fsp)
{
	struct files_struct *fsp = NULL;
	NTSTATUS status;

	status = file_new(NULL, conn, &fsp);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	status = fsp_set_smb_fname(fsp, smb_fname);
	if (!NT_STATUS_IS_OK(status)) {
		file_free(NULL, fsp);
		return status;
	}

	*_fsp = fsp;
	return NT_STATUS_OK;
}

/*
 * Create an internal fsp for an *existing* directory.
 *
 * This should only be used by callers in the VFS that need to control the
 * opening of the directory. Otherwise use open_internal_dirfsp_at().
 */
NTSTATUS create_internal_dirfsp(connection_struct *conn,
				const struct smb_filename *smb_dname,
				struct files_struct **_fsp)
{
	struct files_struct *fsp = NULL;
	NTSTATUS status;

	status = create_internal_fsp(conn, smb_dname, &fsp);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	fsp->access_mask = FILE_LIST_DIRECTORY;
	fsp->fsp_flags.is_directory = true;
	fsp->fsp_flags.is_dirfsp = true;

	*_fsp = fsp;
	return NT_STATUS_OK;
}

/*
 * Open an internal fsp for an *existing* directory.
 */
NTSTATUS open_internal_dirfsp(connection_struct *conn,
			      const struct smb_filename *smb_dname,
			      int open_flags,
			      struct files_struct **_fsp)
{
	struct files_struct *fsp = NULL;
	NTSTATUS status;

	status = create_internal_dirfsp(conn, smb_dname, &fsp);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

#ifdef O_DIRECTORY
	open_flags |= O_DIRECTORY;
#endif
	status = fd_openat(conn->cwd_fsp, fsp->fsp_name, fsp, open_flags, 0);
	if (!NT_STATUS_IS_OK(status)) {
		DBG_INFO("Could not open fd for %s (%s)\n",
			 smb_fname_str_dbg(smb_dname),
			 nt_errstr(status));
		file_free(NULL, fsp);
		return status;
	}

	status = vfs_stat_fsp(fsp);
	if (!NT_STATUS_IS_OK(status)) {
		file_free(NULL, fsp);
		return status;
	}

	if (!S_ISDIR(fsp->fsp_name->st.st_ex_mode)) {
		DBG_ERR("%s is not a directory!\n",
			smb_fname_str_dbg(smb_dname));
                file_free(NULL, fsp);
		return NT_STATUS_NOT_A_DIRECTORY;
	}

	fsp->file_id = vfs_file_id_from_sbuf(conn, &fsp->fsp_name->st);

	*_fsp = fsp;
	return NT_STATUS_OK;
}

/*
 * The "link" in the name doesn't imply link in the filesystem
 * sense. It's a object that "links" together an fsp and an smb_fname
 * and the link allocated as talloc child of an fsp.
 *
 * The link is created for fsps that openat_pathref_fsp() returns in
 * smb_fname->fsp. When this fsp is freed by file_free() by some caller
 * somewhere, the destructor fsp_smb_fname_link_destructor() on the link object
 * will use the link to reset the reference in smb_fname->fsp that is about to
 * go away.
 *
 * This prevents smb_fname_internal_fsp_destructor() from seeing dangling fsp
 * pointers.
 */

struct fsp_smb_fname_link {
	struct fsp_smb_fname_link **smb_fname_link;
	struct files_struct **smb_fname_fsp;
};

static int fsp_smb_fname_link_destructor(struct fsp_smb_fname_link *link)
{
	if (link->smb_fname_link == NULL) {
		return 0;
	}

	*link->smb_fname_link = NULL;
	*link->smb_fname_fsp = NULL;
	return 0;
}

static NTSTATUS fsp_smb_fname_link(struct files_struct *fsp,
				   struct fsp_smb_fname_link **smb_fname_link,
				   struct files_struct **smb_fname_fsp)
{
	struct fsp_smb_fname_link *link = NULL;

	SMB_ASSERT(*smb_fname_link == NULL);
	SMB_ASSERT(*smb_fname_fsp == NULL);

	link = talloc_zero(fsp, struct fsp_smb_fname_link);
	if (link == NULL) {
		return NT_STATUS_NO_MEMORY;
	}

	link->smb_fname_link = smb_fname_link;
	link->smb_fname_fsp = smb_fname_fsp;
	*smb_fname_link = link;
	*smb_fname_fsp = fsp;

	talloc_set_destructor(link, fsp_smb_fname_link_destructor);
	return NT_STATUS_OK;
}

/*
 * Free a link, carefully avoiding to trigger the link destructor
 */
static void destroy_fsp_smb_fname_link(struct fsp_smb_fname_link **_link)
{
	struct fsp_smb_fname_link *link = *_link;

	if (link == NULL) {
		return;
	}
	talloc_set_destructor(link, NULL);
	TALLOC_FREE(link);
	*_link = NULL;
}

/*
 * Talloc destructor set on an smb_fname set by openat_pathref_fsp() used to
 * close the embedded smb_fname->fsp.
 */
static int smb_fname_fsp_destructor(struct smb_filename *smb_fname)
{
	struct files_struct *fsp = smb_fname->fsp;
	NTSTATUS status;
	int saved_errno = errno;

	destroy_fsp_smb_fname_link(&smb_fname->fsp_link);

	if (fsp == NULL) {
		errno = saved_errno;
		return 0;
	}

	if (fsp_is_alternate_stream(fsp)) {
		struct files_struct *tmp_base_fsp = fsp->base_fsp;

		fsp_set_base_fsp(fsp, NULL);

		status = fd_close(tmp_base_fsp);
		SMB_ASSERT(NT_STATUS_IS_OK(status));
		file_free(NULL, tmp_base_fsp);
	}

	status = fd_close(fsp);
	SMB_ASSERT(NT_STATUS_IS_OK(status));
	file_free(NULL, fsp);
	smb_fname->fsp = NULL;

	errno = saved_errno;
	return 0;
}

/*
 * For proper streams support, we have to open the base_fsp for pathref
 * fsp's as well.
 */
static NTSTATUS open_pathref_base_fsp(const struct files_struct *dirfsp,
				      struct smb_filename *smb_fname,
				      struct files_struct *fsp)
{
	struct smb_filename *smb_fname_base = NULL;
	NTSTATUS status;

	smb_fname_base = synthetic_smb_fname(talloc_tos(),
					     smb_fname->base_name,
					     NULL,
					     NULL,
					     smb_fname->twrp,
					     smb_fname->flags);
	if (smb_fname_base == NULL) {
		return NT_STATUS_NO_MEMORY;
	}

	status = openat_pathref_fsp(dirfsp, smb_fname_base);
	if (!NT_STATUS_IS_OK(status)) {
		TALLOC_FREE(smb_fname_base);
		if (!NT_STATUS_EQUAL(status, NT_STATUS_OBJECT_NAME_NOT_FOUND)) {
			DBG_DEBUG("Opening base file failed: %s\n",
				  nt_errstr(status));
			return status;
		}
		return NT_STATUS_OBJECT_NAME_NOT_FOUND;
	}

	fsp_set_base_fsp(fsp, smb_fname_base->fsp);
	smb_fname_fsp_unlink(smb_fname_base);
	TALLOC_FREE(smb_fname_base);

	return NT_STATUS_OK;
}

/*
 * Open an internal O_PATH based fsp for smb_fname. If O_PATH is not
 * available, open O_RDONLY as root. Both is done in fd_open() ->
 * non_widelink_open(), triggered by setting fsp->fsp_flags.is_pathref to
 * true.
 */
NTSTATUS openat_pathref_fsp(const struct files_struct *dirfsp,
			    struct smb_filename *smb_fname)
{
	connection_struct *conn = dirfsp->conn;
	struct smb_filename *full_fname = NULL;
	struct files_struct *fsp = NULL;
	int open_flags = O_RDONLY;
	NTSTATUS status;

	DBG_DEBUG("smb_fname [%s]\n", smb_fname_str_dbg(smb_fname));

	if (smb_fname->fsp != NULL) {
		/* We already have one for this name. */
		DBG_DEBUG("smb_fname [%s] already has a pathref fsp.\n",
			smb_fname_str_dbg(smb_fname));
		return NT_STATUS_OK;
	}

	status = fsp_new(conn, conn, &fsp);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	GetTimeOfDay(&fsp->open_time);
	fsp_set_gen_id(fsp);
	ZERO_STRUCT(conn->sconn->fsp_fi_cache);

	fsp->fsp_flags.is_pathref = true;

	full_fname = full_path_from_dirfsp_atname(fsp,
						  dirfsp,
						  smb_fname);
	if (full_fname == NULL) {
		status = NT_STATUS_NO_MEMORY;
		goto fail;
	}

	status = fsp_attach_smb_fname(fsp, &full_fname);
	if (!NT_STATUS_IS_OK(status)) {
		goto fail;
	}

	if ((conn->fs_capabilities & FILE_NAMED_STREAMS)
	    && is_ntfs_stream_smb_fname(smb_fname))
	{
		/*
		 * We must use smb_fname here, not fsp->fsp_name
		 * as smb_fname is relative to dirfsp, whereas
		 * fsp->fsp_name has been changed above to be
		 * full_fname, relative to the base of the share.
		 */
		status = open_pathref_base_fsp(dirfsp, smb_fname, fsp);
		if (!NT_STATUS_IS_OK(status)) {
			goto fail;
		}
	}

	open_flags |= O_NONBLOCK;

	status = fd_openat(dirfsp, smb_fname, fsp, open_flags, 0);
	if (!NT_STATUS_IS_OK(status)) {
		if (NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND) ||
		    NT_STATUS_EQUAL(status, NT_STATUS_OBJECT_PATH_NOT_FOUND) ||
		    NT_STATUS_EQUAL(status, NT_STATUS_STOPPED_ON_SYMLINK))
		{
			/*
			 * streams_xattr return NT_STATUS_NOT_FOUND for
			 * opens of not yet exisiting streams.
			 *
			 * ELOOP maps to NT_STATUS_OBJECT_PATH_NOT_FOUND
			 * and this will result from a open request from
			 * a POSIX client on a symlink.
			 *
			 * NT_STATUS_OBJECT_NAME_NOT_FOUND is the simple
			 * ENOENT case.
			 *
			 * NT_STATUS_STOPPED_ON_SYMLINK is returned when trying
			 * to open a symlink, our callers are not interested in
			 * this.
			 */
			status = NT_STATUS_OBJECT_NAME_NOT_FOUND;
		}
		goto fail;
	}

	/*
	 * fd_openat() has done an FSTAT on the handle
	 * so update the smb_fname stat info with "truth".
	 * from the handle.
	 */
	smb_fname->st = fsp->fsp_name->st;

	fsp->fsp_flags.is_directory = S_ISDIR(fsp->fsp_name->st.st_ex_mode);

	fsp->file_id = vfs_file_id_from_sbuf(conn, &fsp->fsp_name->st);

	status = fsp_smb_fname_link(fsp,
				    &smb_fname->fsp_link,
				    &smb_fname->fsp);
	if (!NT_STATUS_IS_OK(status)) {
		goto fail;
	}

	DBG_DEBUG("fsp [%s]: OK\n", fsp_str_dbg(fsp));

	talloc_set_destructor(smb_fname, smb_fname_fsp_destructor);
	return NT_STATUS_OK;

fail:
	DBG_DEBUG("Opening pathref for [%s] failed: %s\n",
		  smb_fname_str_dbg(smb_fname),
		  nt_errstr(status));

	if (fsp == NULL) {
		return status;
	}
	if (fsp_is_alternate_stream(fsp)) {
		struct files_struct *tmp_base_fsp = fsp->base_fsp;

		fsp_set_base_fsp(fsp, NULL);

		fd_close(tmp_base_fsp);
		file_free(NULL, tmp_base_fsp);
	}
	fd_close(fsp);
	file_free(NULL, fsp);
	return status;
}

void smb_fname_fsp_unlink(struct smb_filename *smb_fname)
{
	talloc_set_destructor(smb_fname, NULL);
	smb_fname->fsp = NULL;
	destroy_fsp_smb_fname_link(&smb_fname->fsp_link);
}

/*
 * Move any existing embedded fsp refs from the src name to the
 * destination. It's safe to call this on src smb_fname's that have no embedded
 * pathref fsp.
 */
NTSTATUS move_smb_fname_fsp_link(struct smb_filename *smb_fname_dst,
				 struct smb_filename *smb_fname_src)
{
	NTSTATUS status;

	/*
	 * The target should always not be linked yet!
	 */
	SMB_ASSERT(smb_fname_dst->fsp == NULL);
	SMB_ASSERT(smb_fname_dst->fsp_link == NULL);

	if (smb_fname_src->fsp == NULL) {
		return NT_STATUS_OK;
	}

	status = fsp_smb_fname_link(smb_fname_src->fsp,
				    &smb_fname_dst->fsp_link,
				    &smb_fname_dst->fsp);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	talloc_set_destructor(smb_fname_dst, smb_fname_fsp_destructor);

	smb_fname_fsp_unlink(smb_fname_src);

	return NT_STATUS_OK;
}

/**
 * Create an smb_fname and open smb_fname->fsp pathref
 **/
NTSTATUS synthetic_pathref(TALLOC_CTX *mem_ctx,
			   struct files_struct *dirfsp,
			   const char *base_name,
			   const char *stream_name,
			   const SMB_STRUCT_STAT *psbuf,
			   NTTIME twrp,
			   uint32_t flags,
			   struct smb_filename **_smb_fname)
{
	struct smb_filename *smb_fname = NULL;
	NTSTATUS status;

	smb_fname = synthetic_smb_fname(mem_ctx,
					base_name,
					stream_name,
					psbuf,
					twrp,
					flags);
	if (smb_fname == NULL) {
		return NT_STATUS_NO_MEMORY;
	}

	status = openat_pathref_fsp(dirfsp, smb_fname);
	if (!NT_STATUS_IS_OK(status)) {
		DBG_ERR("opening [%s] failed\n",
			smb_fname_str_dbg(smb_fname));
		TALLOC_FREE(smb_fname);
		return status;
	}

	*_smb_fname = smb_fname;
	return NT_STATUS_OK;
}

static int atname_destructor(struct smb_filename *smb_fname)
{
	destroy_fsp_smb_fname_link(&smb_fname->fsp_link);
	return 0;
}

/**
 * Turn a path into a parent pathref and atname
 *
 * This returns the parent pathref in _parent and the name relative to it. If
 * smb_fname was a pathref (ie smb_fname->fsp != NULL), then _atname will be a
 * pathref as well, ie _atname->fsp will point at the same fsp as
 * smb_fname->fsp.
 **/
NTSTATUS parent_pathref(TALLOC_CTX *mem_ctx,
			struct files_struct *dirfsp,
			const struct smb_filename *smb_fname,
			struct smb_filename **_parent,
			struct smb_filename **_atname)
{
	struct smb_filename *parent = NULL;
	struct smb_filename *atname = NULL;
	NTSTATUS status;

	status = SMB_VFS_PARENT_PATHNAME(dirfsp->conn,
					 mem_ctx,
					 smb_fname,
					 &parent,
					 &atname);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	/*
	 * We know that the parent name must
	 * exist, and the name has been canonicalized
	 * even if this was a POSIX pathname.
	 * Ensure that we follow symlinks for
	 * the parent. See the torture test
	 * POSIX-SYMLINK-PARENT for details.
	 */
	parent->flags &= ~SMB_FILENAME_POSIX_PATH;

	status = openat_pathref_fsp(dirfsp, parent);
	if (!NT_STATUS_IS_OK(status)) {
		TALLOC_FREE(parent);
		return status;
	}

	if (smb_fname->fsp != NULL) {
		status = fsp_smb_fname_link(smb_fname->fsp,
					    &atname->fsp_link,
					    &atname->fsp);
		if (!NT_STATUS_IS_OK(status)) {
			TALLOC_FREE(parent);
			return status;
		}
		talloc_set_destructor(atname, atname_destructor);
	}
	*_parent = parent;
	*_atname = atname;
	return NT_STATUS_OK;
}

static bool close_file_in_loop(struct files_struct *fsp)
{
	if (fsp_is_alternate_stream(fsp)) {
		/*
		 * This is a stream, it can't be a base
		 */
		SMB_ASSERT(fsp->stream_fsp == NULL);
		SMB_ASSERT(fsp->base_fsp->stream_fsp == fsp);

		/*
		 * Remove the base<->stream link so that
		 * close_file_free() does not close fsp->base_fsp as
		 * well. This would destroy walking the linked list of
		 * fsps.
		 */
		fsp->base_fsp->stream_fsp = NULL;
		fsp->base_fsp = NULL;

		close_file_free(NULL, &fsp, SHUTDOWN_CLOSE);
		return NULL;
	}

	if (fsp->stream_fsp != NULL) {
		/*
		 * This is the base of a stream.
		 */
		SMB_ASSERT(fsp->stream_fsp->base_fsp == fsp);

		/*
		 * Remove the base<->stream link. This will make fsp
		 * look like a normal fsp for the next round.
		 */
		fsp->stream_fsp->base_fsp = NULL;
		fsp->stream_fsp = NULL;

		/*
		 * Have us called back a second time. In the second
		 * round, "fsp" now looks like a normal fsp.
		 */
		return false;
	}

	close_file_free(NULL, &fsp, SHUTDOWN_CLOSE);
	return true;
}

/****************************************************************************
 Close all open files for a connection.
****************************************************************************/

struct file_close_conn_state {
	struct connection_struct *conn;
	bool fsp_left_behind;
};

static struct files_struct *file_close_conn_fn(
	struct files_struct *fsp,
	void *private_data)
{
	struct file_close_conn_state *state = private_data;
	bool did_close;

	if (fsp->conn != state->conn) {
		return NULL;
	}

	if (fsp->op != NULL && fsp->op->global->durable) {
		/*
		 * A tree disconnect closes a durable handle
		 */
		fsp->op->global->durable = false;
	}

	did_close = close_file_in_loop(fsp);
	if (!did_close) {
		state->fsp_left_behind = true;
	}

	return NULL;
}

void file_close_conn(connection_struct *conn)
{
	struct file_close_conn_state state = { .conn = conn };

	files_forall(conn->sconn, file_close_conn_fn, &state);

	if (state.fsp_left_behind) {
		state.fsp_left_behind = false;
		files_forall(conn->sconn, file_close_conn_fn, &state);
		SMB_ASSERT(!state.fsp_left_behind);
	}
}

/****************************************************************************
 Initialise file structures.
****************************************************************************/

static int files_max_open_fds;

bool file_init_global(void)
{
	int request_max = lp_max_open_files();
	int real_lim;
	int real_max;

	if (files_max_open_fds != 0) {
		return true;
	}

	/*
	 * Set the max_open files to be the requested
	 * max plus a fudgefactor to allow for the extra
	 * fd's we need such as log files etc...
	 */
	real_lim = set_maxfiles(request_max + MAX_OPEN_FUDGEFACTOR);

	real_max = real_lim - MAX_OPEN_FUDGEFACTOR;

	if (real_max + FILE_HANDLE_OFFSET + MAX_OPEN_PIPES > 65536) {
		real_max = 65536 - FILE_HANDLE_OFFSET - MAX_OPEN_PIPES;
	}

	if (real_max != request_max) {
		DEBUG(1, ("file_init_global: Information only: requested %d "
			  "open files, %d are available.\n",
			  request_max, real_max));
	}

	SMB_ASSERT(real_max > 100);

	files_max_open_fds = real_max;
	return true;
}

bool file_init(struct smbd_server_connection *sconn)
{
	bool ok;

	ok = file_init_global();
	if (!ok) {
		return false;
	}

	sconn->real_max_open_files = files_max_open_fds;

	return true;
}

/****************************************************************************
 Close files open by a specified vuid.
****************************************************************************/

struct file_close_user_state {
	uint64_t vuid;
	bool fsp_left_behind;
};

static struct files_struct *file_close_user_fn(
	struct files_struct *fsp,
	void *private_data)
{
	struct file_close_user_state *state = private_data;
	bool did_close;

	if (fsp->vuid != state->vuid) {
		return NULL;
	}

	did_close = close_file_in_loop(fsp);
	if (!did_close) {
		state->fsp_left_behind = true;
	}

	return NULL;
}

void file_close_user(struct smbd_server_connection *sconn, uint64_t vuid)
{
	struct file_close_user_state state = { .vuid = vuid };

	files_forall(sconn, file_close_user_fn, &state);

	if (state.fsp_left_behind) {
		state.fsp_left_behind = false;
		files_forall(sconn, file_close_user_fn, &state);
		SMB_ASSERT(!state.fsp_left_behind);
	}
}

/*
 * Walk the files table until "fn" returns non-NULL
 */

struct files_struct *files_forall(
	struct smbd_server_connection *sconn,
	struct files_struct *(*fn)(struct files_struct *fsp,
				   void *private_data),
	void *private_data)
{
	struct files_struct *fsp, *next;

	for (fsp = sconn->files; fsp; fsp = next) {
		struct files_struct *ret;
		next = fsp->next;
		ret = fn(fsp, private_data);
		if (ret != NULL) {
			return ret;
		}
	}
	return NULL;
}

/****************************************************************************
 Find a fsp given a file descriptor.
****************************************************************************/

files_struct *file_find_fd(struct smbd_server_connection *sconn, int fd)
{
	int count=0;
	files_struct *fsp;

	for (fsp=sconn->files; fsp; fsp=fsp->next,count++) {
		if (fsp_get_pathref_fd(fsp) == fd) {
			if (count > 10) {
				DLIST_PROMOTE(sconn->files, fsp);
			}
			return fsp;
		}
	}

	return NULL;
}

/****************************************************************************
 Find a fsp given a device, inode and file_id.
****************************************************************************/

files_struct *file_find_dif(struct smbd_server_connection *sconn,
			    struct file_id id, unsigned long gen_id)
{
	int count=0;
	files_struct *fsp;

	if (gen_id == 0) {
		return NULL;
	}

	for (fsp = sconn->files; fsp; fsp = fsp->next,count++) {
		/*
		 * We can have a fsp->fh->fd == -1 here as it could be a stat
		 * open.
		 */
		if (!file_id_equal(&fsp->file_id, &id)) {
			continue;
		}
		if (!fsp->fsp_flags.is_fsa) {
			continue;
		}
		if (fh_get_gen_id(fsp->fh) != gen_id) {
			continue;
		}
		if (count > 10) {
			DLIST_PROMOTE(sconn->files, fsp);
		}
		/* Paranoia check. */
		if ((fsp_get_pathref_fd(fsp) == -1) &&
		    (fsp->oplock_type != NO_OPLOCK &&
		     fsp->oplock_type != LEASE_OPLOCK))
		{
			struct file_id_buf idbuf;

			DBG_ERR("file %s file_id = "
				"%s, gen = %u oplock_type = %u is a "
				"stat open with oplock type !\n",
				fsp_str_dbg(fsp),
				file_id_str_buf(fsp->file_id, &idbuf),
				(unsigned int)fh_get_gen_id(fsp->fh),
				(unsigned int)fsp->oplock_type);
			smb_panic("file_find_dif");
		}
		return fsp;
	}

	return NULL;
}

/****************************************************************************
 Find the first fsp given a device and inode.
 We use a singleton cache here to speed up searching from getfilepathinfo
 calls.
****************************************************************************/

files_struct *file_find_di_first(struct smbd_server_connection *sconn,
				 struct file_id id,
				 bool need_fsa)
{
	files_struct *fsp;

	if (file_id_equal(&sconn->fsp_fi_cache.id, &id)) {
		/* Positive or negative cache hit. */
		return sconn->fsp_fi_cache.fsp;
	}

	sconn->fsp_fi_cache.id = id;

	for (fsp=sconn->files;fsp;fsp=fsp->next) {
		if (need_fsa && !fsp->fsp_flags.is_fsa) {
			continue;
		}
		if (file_id_equal(&fsp->file_id, &id)) {
			/* Setup positive cache. */
			sconn->fsp_fi_cache.fsp = fsp;
			return fsp;
		}
	}

	/* Setup negative cache. */
	sconn->fsp_fi_cache.fsp = NULL;
	return NULL;
}

/****************************************************************************
 Find the next fsp having the same device and inode.
****************************************************************************/

files_struct *file_find_di_next(files_struct *start_fsp,
				bool need_fsa)
{
	files_struct *fsp;

	for (fsp = start_fsp->next;fsp;fsp=fsp->next) {
		if (need_fsa && !fsp->fsp_flags.is_fsa) {
			continue;
		}
		if (file_id_equal(&fsp->file_id, &start_fsp->file_id)) {
			return fsp;
		}
	}

	return NULL;
}

struct files_struct *file_find_one_fsp_from_lease_key(
	struct smbd_server_connection *sconn,
	const struct smb2_lease_key *lease_key)
{
	struct files_struct *fsp;

	for (fsp = sconn->files; fsp; fsp=fsp->next) {
		if ((fsp->lease != NULL) &&
		    (fsp->lease->lease.lease_key.data[0] ==
		     lease_key->data[0]) &&
		    (fsp->lease->lease.lease_key.data[1] ==
		     lease_key->data[1])) {
			return fsp;
		}
	}
	return NULL;
}

/****************************************************************************
 Find any fsp open with a pathname below that of an already open path.
****************************************************************************/

bool file_find_subpath(files_struct *dir_fsp)
{
	files_struct *fsp;
	size_t dlen;
	char *d_fullname = NULL;

	d_fullname = talloc_asprintf(talloc_tos(), "%s/%s",
				     dir_fsp->conn->connectpath,
				     dir_fsp->fsp_name->base_name);

	if (!d_fullname) {
		return false;
	}

	dlen = strlen(d_fullname);

	for (fsp=dir_fsp->conn->sconn->files; fsp; fsp=fsp->next) {
		char *d1_fullname;

		if (fsp == dir_fsp) {
			continue;
		}

		d1_fullname = talloc_asprintf(talloc_tos(),
					"%s/%s",
					fsp->conn->connectpath,
					fsp->fsp_name->base_name);

		/*
		 * If the open file has a path that is a longer
		 * component, then it's a subpath.
		 */
		if (strnequal(d_fullname, d1_fullname, dlen) &&
				(d1_fullname[dlen] == '/')) {
			TALLOC_FREE(d1_fullname);
			TALLOC_FREE(d_fullname);
			return true;
		}
		TALLOC_FREE(d1_fullname);
	}

	TALLOC_FREE(d_fullname);
	return false;
}

/****************************************************************************
 Free up a fsp.
****************************************************************************/

static void fsp_free(files_struct *fsp)
{
	struct smbd_server_connection *sconn = fsp->conn->sconn;

	if (fsp == sconn->fsp_fi_cache.fsp) {
		ZERO_STRUCT(sconn->fsp_fi_cache);
	}

	DLIST_REMOVE(sconn->files, fsp);
	SMB_ASSERT(sconn->num_files > 0);
	sconn->num_files--;

	TALLOC_FREE(fsp->fake_file_handle);

	if (fh_get_refcount(fsp->fh) == 1) {
		TALLOC_FREE(fsp->fh);
	} else {
		size_t new_refcount = fh_get_refcount(fsp->fh) - 1;
		fh_set_refcount(fsp->fh, new_refcount);
	}

	if (fsp->lease != NULL) {
		if (fsp->lease->ref_count == 1) {
			TALLOC_FREE(fsp->lease);
		} else {
			fsp->lease->ref_count--;
		}
	}

	fsp->conn->num_files_open--;

	if (fsp->fsp_name != NULL &&
	    fsp->fsp_name->fsp_link != NULL)
	{
		/*
		 * Free fsp_link of fsp->fsp_name. To do this in the correct
		 * talloc destructor order we have to do it here. The
		 * talloc_free() of the link should set the fsp pointer to NULL.
		 */
		TALLOC_FREE(fsp->fsp_name->fsp_link);
		SMB_ASSERT(fsp->fsp_name->fsp == NULL);
	}

	/* this is paranoia, just in case someone tries to reuse the
	   information */
	ZERO_STRUCTP(fsp);

	/* fsp->fsp_name is a talloc child and is free'd automatically. */
	TALLOC_FREE(fsp);
}

/*
 * Rundown of all smb-related sub-structures of an fsp
 */
void fsp_unbind_smb(struct smb_request *req, files_struct *fsp)
{
	if (fsp == fsp->conn->cwd_fsp) {
		return;
	}

	if (fsp->notify) {
		size_t len = fsp_fullbasepath(fsp, NULL, 0);
		char fullpath[len+1];

		fsp_fullbasepath(fsp, fullpath, sizeof(fullpath));

		/*
		 * Avoid /. at the end of the path name. notify can't
		 * deal with it.
		 */
		if (len > 1 && fullpath[len-1] == '.' &&
		    fullpath[len-2] == '/') {
			fullpath[len-2] = '\0';
		}

		notify_remove(fsp->conn->sconn->notify_ctx, fsp, fullpath);
		TALLOC_FREE(fsp->notify);
	}

	/* Ensure this event will never fire. */
	TALLOC_FREE(fsp->update_write_time_event);

	if (fsp->op != NULL) {
		fsp->op->compat = NULL;
	}
	TALLOC_FREE(fsp->op);

	if ((req != NULL) && (fsp == req->chain_fsp)) {
		req->chain_fsp = NULL;
	}

	/*
	 * Clear all possible chained fsp
	 * pointers in the SMB2 request queue.
	 */
	remove_smb2_chained_fsp(fsp);
}

void file_free(struct smb_request *req, files_struct *fsp)
{
	struct smbd_server_connection *sconn = fsp->conn->sconn;
	uint64_t fnum = fsp->fnum;

	fsp_unbind_smb(req, fsp);

	/* Drop all remaining extensions. */
	vfs_remove_all_fsp_extensions(fsp);

	fsp_free(fsp);

	DBG_INFO("freed files structure %"PRIu64" (%zu used)\n",
		 fnum,
		 sconn->num_files);
}

/****************************************************************************
 Get an fsp from a packet given a 16 bit fnum.
****************************************************************************/

files_struct *file_fsp(struct smb_request *req, uint16_t fid)
{
	struct smbXsrv_open *op;
	NTSTATUS status;
	NTTIME now = 0;
	files_struct *fsp;

	if (req == NULL) {
		/*
		 * We should never get here. req==NULL could in theory
		 * only happen from internal opens with a non-zero
		 * root_dir_fid. Internal opens just don't do that, at
		 * least they are not supposed to do so. And if they
		 * start to do so, they better fake up a smb_request
		 * from which we get the right smbd_server_conn. While
		 * this should never happen, let's return NULL here.
		 */
		return NULL;
	}

	if (req->chain_fsp != NULL) {
		if (req->chain_fsp->fsp_flags.closing) {
			return NULL;
		}
		return req->chain_fsp;
	}

	if (req->xconn == NULL) {
		return NULL;
	}

	now = timeval_to_nttime(&req->request_time);

	status = smb1srv_open_lookup(req->xconn,
				     fid, now, &op);
	if (!NT_STATUS_IS_OK(status)) {
		return NULL;
	}

	fsp = op->compat;
	if (fsp == NULL) {
		return NULL;
	}

	if (fsp->fsp_flags.closing) {
		return NULL;
	}

	req->chain_fsp = fsp;
	return fsp;
}

struct files_struct *file_fsp_get(struct smbd_smb2_request *smb2req,
				  uint64_t persistent_id,
				  uint64_t volatile_id)
{
	struct smbXsrv_open *op;
	NTSTATUS status;
	NTTIME now = 0;
	struct files_struct *fsp;

	now = timeval_to_nttime(&smb2req->request_time);

	status = smb2srv_open_lookup(smb2req->xconn,
				     persistent_id, volatile_id,
				     now, &op);
	if (!NT_STATUS_IS_OK(status)) {
		return NULL;
	}

	fsp = op->compat;
	if (fsp == NULL) {
		return NULL;
	}

	if (smb2req->tcon == NULL) {
		return NULL;
	}

	if (smb2req->tcon->compat != fsp->conn) {
		return NULL;
	}

	if (smb2req->session == NULL) {
		return NULL;
	}

	if (smb2req->session->global->session_wire_id != fsp->vuid) {
		return NULL;
	}

	if (fsp->fsp_flags.closing) {
		return NULL;
	}

	return fsp;
}

struct files_struct *file_fsp_smb2(struct smbd_smb2_request *smb2req,
				   uint64_t persistent_id,
				   uint64_t volatile_id)
{
	struct files_struct *fsp;

	if (smb2req->compat_chain_fsp != NULL) {
		if (smb2req->compat_chain_fsp->fsp_flags.closing) {
			return NULL;
		}
		return smb2req->compat_chain_fsp;
	}

	fsp = file_fsp_get(smb2req, persistent_id, volatile_id);
	if (fsp == NULL) {
		return NULL;
	}

	smb2req->compat_chain_fsp = fsp;
	return fsp;
}

/****************************************************************************
 Duplicate the file handle part for a DOS or FCB open.
****************************************************************************/

NTSTATUS dup_file_fsp(
	struct smb_request *req,
	files_struct *from,
	uint32_t access_mask,
	uint32_t create_options,
	files_struct *to)
{
	size_t new_refcount;

	/* this can never happen for print files */
	SMB_ASSERT(from->print_file == NULL);

	TALLOC_FREE(to->fh);

	to->fh = from->fh;
	new_refcount = fh_get_refcount(to->fh) + 1;
	fh_set_refcount(to->fh, new_refcount);

	to->file_id = from->file_id;
	to->initial_allocation_size = from->initial_allocation_size;
	to->file_pid = from->file_pid;
	to->vuid = from->vuid;
	to->open_time = from->open_time;
	to->access_mask = access_mask;
	to->oplock_type = from->oplock_type;
	to->fsp_flags.can_lock = from->fsp_flags.can_lock;
	to->fsp_flags.can_read = ((access_mask & FILE_READ_DATA) != 0);
	to->fsp_flags.can_write =
		CAN_WRITE(from->conn) &&
		((access_mask & (FILE_WRITE_DATA | FILE_APPEND_DATA)) != 0);
	to->fsp_flags.modified = from->fsp_flags.modified;
	to->fsp_flags.is_directory = from->fsp_flags.is_directory;
	to->fsp_flags.aio_write_behind = from->fsp_flags.aio_write_behind;
	to->fsp_flags.is_fsa = from->fsp_flags.is_fsa;
	to->fsp_flags.is_pathref = from->fsp_flags.is_pathref;
	to->fsp_flags.have_proc_fds = from->fsp_flags.have_proc_fds;
	to->fsp_flags.is_dirfsp = from->fsp_flags.is_dirfsp;

	return fsp_set_smb_fname(to, from->fsp_name);
}

/**
 * Return a jenkins hash of a pathname on a connection.
 */

NTSTATUS file_name_hash(connection_struct *conn,
			const char *name, uint32_t *p_name_hash)
{
	char tmpbuf[PATH_MAX];
	char *fullpath, *to_free;
	ssize_t len;
	TDB_DATA key;

	/* Set the hash of the full pathname. */

	if (name[0] == '/') {
		strlcpy(tmpbuf, name, sizeof(tmpbuf));
		fullpath = tmpbuf;
		len = strlen(fullpath);
		to_free = NULL;
	} else {
		len = full_path_tos(conn->connectpath,
				    name,
				    tmpbuf,
				    sizeof(tmpbuf),
				    &fullpath,
				    &to_free);
	}
	if (len == -1) {
		return NT_STATUS_NO_MEMORY;
	}
	key = (TDB_DATA) { .dptr = (uint8_t *)fullpath, .dsize = len+1 };
	*p_name_hash = tdb_jenkins_hash(&key);

	DEBUG(10,("file_name_hash: %s hash 0x%x\n",
		  fullpath,
		(unsigned int)*p_name_hash ));

	TALLOC_FREE(to_free);
	return NT_STATUS_OK;
}

static NTSTATUS fsp_attach_smb_fname(struct files_struct *fsp,
				     struct smb_filename **_smb_fname)
{
	struct smb_filename *smb_fname_new = *_smb_fname;
	const char *name_str = NULL;
	uint32_t name_hash = 0;
	NTSTATUS status;

	name_str = smb_fname_str_dbg(smb_fname_new);
	if (name_str == NULL) {
		return NT_STATUS_NO_MEMORY;
	}

	status = file_name_hash(fsp->conn,
				name_str,
				&name_hash);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	status = fsp_smb_fname_link(fsp,
				    &smb_fname_new->fsp_link,
				    &smb_fname_new->fsp);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	fsp->name_hash = name_hash;
	fsp->fsp_name = smb_fname_new;
	*_smb_fname = NULL;
	return NT_STATUS_OK;
}

/**
 * The only way that the fsp->fsp_name field should ever be set.
 */
NTSTATUS fsp_set_smb_fname(struct files_struct *fsp,
			   const struct smb_filename *smb_fname_in)
{
	struct smb_filename *smb_fname_old = fsp->fsp_name;
	struct smb_filename *smb_fname_new = NULL;
	NTSTATUS status;

	smb_fname_new = cp_smb_filename(fsp, smb_fname_in);
	if (smb_fname_new == NULL) {
		return NT_STATUS_NO_MEMORY;
	}

	status = fsp_attach_smb_fname(fsp, &smb_fname_new);
	if (!NT_STATUS_IS_OK(status)) {
		TALLOC_FREE(smb_fname_new);
		return status;
	}

	if (smb_fname_old != NULL) {
		smb_fname_fsp_unlink(smb_fname_old);
		TALLOC_FREE(smb_fname_old);
	}

	return NT_STATUS_OK;
}

size_t fsp_fullbasepath(struct files_struct *fsp, char *buf, size_t buflen)
{
	int len = 0;
	char tmp_buf[1] = {'\0'};

	/*
	 * Don't pass NULL buffer to snprintf (to satisfy static checker)
	 * Some callers will call this function with NULL for buf and
	 * 0 for buflen in order to get length of fullbasepath (without
	 * needing to allocate or write to buf)
	 */
	if (buf == NULL) {
		buf = tmp_buf;
		SMB_ASSERT(buflen==0);
	}

	len = snprintf(buf, buflen, "%s/%s", fsp->conn->connectpath,
		       fsp->fsp_name->base_name);
	SMB_ASSERT(len>0);

	return len;
}

void fsp_set_base_fsp(struct files_struct *fsp, struct files_struct *base_fsp)
{
	SMB_ASSERT(fsp->stream_fsp == NULL);
	if (base_fsp != NULL) {
		SMB_ASSERT(base_fsp->base_fsp == NULL);
		SMB_ASSERT(base_fsp->stream_fsp == NULL);
	}

	if (fsp->base_fsp != NULL) {
		SMB_ASSERT(fsp->base_fsp->stream_fsp == fsp);
		fsp->base_fsp->stream_fsp = NULL;
	}

	fsp->base_fsp = base_fsp;
	if (fsp->base_fsp != NULL) {
		fsp->base_fsp->stream_fsp = fsp;
	}
}

bool fsp_is_alternate_stream(const struct files_struct *fsp)
{
	return (fsp->base_fsp != NULL);
}

struct files_struct *metadata_fsp(struct files_struct *fsp)
{
	if (fsp_is_alternate_stream(fsp)) {
		return fsp->base_fsp;
	}
	return fsp;
}