smbd: Simplify openat_pathref_fsp_case_insensitive()

[Samba.git] / 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"
#include "lib/util/strv.h"
#include "lib/util/memcache.h"
#include "libcli/smb/reparse.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 vfs_open_how how = { .flags = _open_flags, };
        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
        how.flags |= O_DIRECTORY;
#endif
        status = fd_openat(conn->cwd_fsp, fsp->fsp_name, fsp, &how);
        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;
}

/*
 * Convert a pathref dirfsp into a real fsp. No need to do any cwd
 * tricks, we just open ".".
 */
NTSTATUS openat_internal_dir_from_pathref(
        struct files_struct *dirfsp,
        int _open_flags,
        struct files_struct **_fsp)
{
        struct connection_struct *conn = dirfsp->conn;
        struct smb_filename *smb_dname = dirfsp->fsp_name;
        struct files_struct *fsp = NULL;
        char dot[] = ".";
        struct smb_filename smb_dot = {
                .base_name = dot,
                .flags = smb_dname->flags,
                .twrp = smb_dname->twrp,
        };
        struct vfs_open_how how = { .flags = _open_flags, };
        NTSTATUS status;

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

        /*
         * Pointless for opening ".", but you never know...
         */
        how.flags |= O_NOFOLLOW;

        status = fd_openat(dirfsp, &smb_dot, fsp, &how);
        if (!NT_STATUS_IS_OK(status)) {
                DBG_INFO("fd_openat(\"%s\", \".\") failed: %s\n",
                         fsp_str_dbg(dirfsp),
                         nt_errstr(status));
                file_free(NULL, fsp);
                return status;
        }

        fsp->fsp_name->st = smb_dname->st;
        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);
                if (!NT_STATUS_IS_OK(status)) {
                        DBG_ERR("Closing fd for fsp [%s] failed: %s. "
                                "Please check your filesystem!!!\n",
                                fsp_str_dbg(fsp), nt_errstr(status));
                }
                file_free(NULL, tmp_base_fsp);
        }

        status = fd_close(fsp);
        if (!NT_STATUS_IS_OK(status)) {
                DBG_ERR("Closing fd for fsp [%s] failed: %s. "
                        "Please check your filesystem!!!\n",
                        fsp_str_dbg(fsp), nt_errstr(status));
        }
        file_free(NULL, fsp);
        smb_fname->fsp = NULL;

        errno = saved_errno;
        return 0;
}

static NTSTATUS openat_pathref_fullname(
        struct connection_struct *conn,
        const struct files_struct *dirfsp,
        struct files_struct *basefsp,
        struct smb_filename **full_fname,
        struct smb_filename *smb_fname,
        const struct vfs_open_how *how)
{
        struct files_struct *fsp = NULL;
        bool have_dirfsp = (dirfsp != NULL);
        bool have_basefsp = (basefsp != NULL);
        NTSTATUS status;

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

        SMB_ASSERT(smb_fname->fsp == NULL);
        SMB_ASSERT(have_dirfsp != have_basefsp);

        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;

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

        status = fd_openat(dirfsp, smb_fname, fsp, how);
        if (!NT_STATUS_IS_OK(status)) {

                smb_fname->st = fsp->fsp_name->st;

                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 existing 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));

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

/*
 * 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 smb_filename *base_fname = NULL;
        struct vfs_open_how how = { .flags = O_RDONLY|O_NONBLOCK, };
        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;
        }

        if (is_named_stream(smb_fname) &&
            ((conn->fs_capabilities & FILE_NAMED_STREAMS) == 0)) {
                DBG_DEBUG("stream open [%s] on non-stream share\n",
                          smb_fname_str_dbg(smb_fname));
                return NT_STATUS_OBJECT_NAME_INVALID;
        }

        if (!is_named_stream(smb_fname)) {
                /*
                 * openat_pathref_fullname() will make "full_fname" a
                 * talloc child of the smb_fname->fsp. Don't use
                 * talloc_tos() to allocate it to avoid making the
                 * talloc stackframe pool long-lived.
                 */
                full_fname = full_path_from_dirfsp_atname(
                        conn,
                        dirfsp,
                        smb_fname);
                if (full_fname == NULL) {
                        status = NT_STATUS_NO_MEMORY;
                        goto fail;
                }
                status = openat_pathref_fullname(
                        conn, dirfsp, NULL, &full_fname, smb_fname, &how);
                TALLOC_FREE(full_fname);
                return status;
        }

        /*
         * stream open
         */
        base_fname = cp_smb_filename_nostream(conn, smb_fname);
        if (base_fname == NULL) {
                return NT_STATUS_NO_MEMORY;
        }

        full_fname = full_path_from_dirfsp_atname(
                conn,   /* no talloc_tos(), see comment above */
                dirfsp,
                base_fname);
        if (full_fname == NULL) {
                status = NT_STATUS_NO_MEMORY;
                goto fail;
        }

        status = openat_pathref_fullname(
                conn, dirfsp, NULL, &full_fname, base_fname, &how);
        TALLOC_FREE(full_fname);
        if (!NT_STATUS_IS_OK(status)) {
                DBG_DEBUG("openat_pathref_fullname() failed: %s\n",
                          nt_errstr(status));
                goto fail;
        }

        status = open_stream_pathref_fsp(&base_fname->fsp, smb_fname);
        if (!NT_STATUS_IS_OK(status)) {
                DBG_DEBUG("open_stream_pathref_fsp failed: %s\n",
                          nt_errstr(status));
                goto fail;
        }

        smb_fname_fsp_unlink(base_fname);
fail:
        TALLOC_FREE(base_fname);
        return status;
}

/*
 * Open a stream given an already opened base_fsp. Avoid
 * non_widelink_open: This is only valid for the case where we have a
 * valid non-cwd_fsp dirfsp that we can pass to SMB_VFS_OPENAT()
 */
NTSTATUS open_stream_pathref_fsp(
        struct files_struct **_base_fsp,
        struct smb_filename *smb_fname)
{
        struct files_struct *base_fsp = *_base_fsp;
        connection_struct *conn = base_fsp->conn;
        struct smb_filename *base_fname = base_fsp->fsp_name;
        struct smb_filename *full_fname = NULL;
        struct vfs_open_how how = { .flags = O_RDONLY|O_NONBLOCK, };
        NTSTATUS status;

        SMB_ASSERT(smb_fname->fsp == NULL);
        SMB_ASSERT(is_named_stream(smb_fname));

        full_fname = synthetic_smb_fname(
                conn, /* no talloc_tos(), this will be long-lived */
                base_fname->base_name,
                smb_fname->stream_name,
                &smb_fname->st,
                smb_fname->twrp,
                smb_fname->flags);
        if (full_fname == NULL) {
                return NT_STATUS_NO_MEMORY;
        }

        status = openat_pathref_fullname(
                conn, NULL, base_fsp, &full_fname, smb_fname, &how);
        TALLOC_FREE(full_fname);
        return status;
}

static char *path_to_strv(TALLOC_CTX *mem_ctx, const char *path)
{
        char *result = talloc_strdup(mem_ctx, path);

        if (result == NULL) {
                return NULL;
        }
        string_replace(result, '/', '\0');
        return result;
}

NTSTATUS readlink_talloc(
        TALLOC_CTX *mem_ctx,
        struct files_struct *dirfsp,
        struct smb_filename *smb_relname,
        char **_substitute)
{
        struct smb_filename null_fname = {
                .base_name = discard_const_p(char, ""),
        };
        char buf[PATH_MAX];
        ssize_t ret;
        char *substitute;
        NTSTATUS status;

        if (smb_relname == NULL) {
                /*
                 * We have a Linux O_PATH handle in dirfsp and want to
                 * read its value, essentially a freadlink
                 */
                smb_relname = &null_fname;
        }

        ret = SMB_VFS_READLINKAT(
                dirfsp->conn, dirfsp, smb_relname, buf, sizeof(buf));
        if (ret < 0) {
                status = map_nt_error_from_unix(errno);
                DBG_DEBUG("SMB_VFS_READLINKAT() failed: %s\n",
                          strerror(errno));
                return status;
        }

        if ((size_t)ret == sizeof(buf)) {
                /*
                 * Do we need symlink targets longer than PATH_MAX?
                 */
                DBG_DEBUG("Got full %zu bytes from readlink, too long\n",
                          sizeof(buf));
                return NT_STATUS_BUFFER_OVERFLOW;
        }

        substitute = talloc_strndup(mem_ctx, buf, ret);
        if (substitute == NULL) {
                DBG_DEBUG("talloc_strndup() failed\n");
                return NT_STATUS_NO_MEMORY;
        }

        *_substitute = substitute;
        return NT_STATUS_OK;
}

NTSTATUS read_symlink_reparse(
        TALLOC_CTX *mem_ctx,
        struct files_struct *dirfsp,
        struct smb_filename *smb_relname,
        struct symlink_reparse_struct **_symlink)
{
        struct symlink_reparse_struct *symlink = NULL;
        NTSTATUS status;

        symlink = talloc_zero(mem_ctx, struct symlink_reparse_struct);
        if (symlink == NULL) {
                goto nomem;
        }

        status = readlink_talloc(
                symlink, dirfsp, smb_relname, &symlink->substitute_name);
        if (!NT_STATUS_IS_OK(status)) {
                DBG_DEBUG("readlink_talloc failed: %s\n", nt_errstr(status));
                goto fail;
        }

        if (symlink->substitute_name[0] == '/') {
                char *subdir_path = NULL;
                char *abs_target_canon = NULL;
                const char *relative = NULL;
                bool in_share;

                subdir_path = talloc_asprintf(talloc_tos(),
                                              "%s/%s",
                                              dirfsp->conn->connectpath,
                                              dirfsp->fsp_name->base_name);
                if (subdir_path == NULL) {
                        goto nomem;
                }

                abs_target_canon =
                        canonicalize_absolute_path(talloc_tos(),
                                                   symlink->substitute_name);
                if (abs_target_canon == NULL) {
                        goto nomem;
                }

                in_share = subdir_of(subdir_path,
                                     strlen(subdir_path),
                                     abs_target_canon,
                                     &relative);
                if (in_share) {
                        TALLOC_FREE(symlink->substitute_name);
                        symlink->substitute_name =
                                talloc_strdup(symlink, relative);
                        if (symlink->substitute_name == NULL) {
                                goto nomem;
                        }
                }
        }

        if (!IS_DIRECTORY_SEP(symlink->substitute_name[0])) {
                symlink->flags |= SYMLINK_FLAG_RELATIVE;
        }

        *_symlink = symlink;
        return NT_STATUS_OK;
nomem:
        status = NT_STATUS_NO_MEMORY;
fail:
        TALLOC_FREE(symlink);
        return status;
}

static bool full_path_extend(char **dir, const char *atname)
{
        talloc_asprintf_addbuf(dir,
                               "%s%s",
                               (*dir)[0] == '\0' ? "" : "/",
                               atname);
        return (*dir) != NULL;
}

NTSTATUS create_open_symlink_err(TALLOC_CTX *mem_ctx,
                                 files_struct *dirfsp,
                                 struct smb_filename *smb_relname,
                                 struct open_symlink_err **_err)
{
        struct open_symlink_err *err = NULL;
        NTSTATUS status;

        err = talloc_zero(mem_ctx, struct open_symlink_err);
        if (err == NULL) {
                return NT_STATUS_NO_MEMORY;
        }

        status = read_symlink_reparse(err, dirfsp, smb_relname, &err->reparse);
        if (!NT_STATUS_IS_OK(status)) {
                TALLOC_FREE(err);
                return status;
        }

        *_err = err;
        return NT_STATUS_OK;
}

static int smb_vfs_openat_ci(TALLOC_CTX *mem_ctx,
                             bool case_sensitive,
                             struct connection_struct *conn,
                             struct files_struct *dirfsp,
                             struct smb_filename *smb_fname_rel,
                             files_struct *fsp,
                             const struct vfs_open_how *how)
{
        char *orig_base_name = smb_fname_rel->base_name;
        DATA_BLOB cache_key = {
                .data = NULL,
        };
        DATA_BLOB cache_value = {
                .data = NULL,
        };
        NTSTATUS status;
        int fd;
        bool ok;

        fd = SMB_VFS_OPENAT(conn, dirfsp, smb_fname_rel, fsp, how);
        if ((fd >= 0) || case_sensitive) {
                return fd;
        }
        if (errno != ENOENT) {
                return -1;
        }

        if (!lp_stat_cache()) {
                goto lookup;
        }

        ok = get_real_filename_cache_key(mem_ctx,
                                         dirfsp,
                                         orig_base_name,
                                         &cache_key);
        if (!ok) {
                /*
                 * probably ENOMEM, just bail
                 */
                errno = ENOMEM;
                return -1;
        }

        DO_PROFILE_INC(statcache_lookups);

        ok = memcache_lookup(NULL,
                             GETREALFILENAME_CACHE,
                             cache_key,
                             &cache_value);
        if (!ok) {
                DO_PROFILE_INC(statcache_misses);
                goto lookup;
        }
        DO_PROFILE_INC(statcache_hits);

        smb_fname_rel->base_name = talloc_strndup(mem_ctx,
                                                  (char *)cache_value.data,
                                                  cache_value.length);
        if (smb_fname_rel->base_name == NULL) {
                TALLOC_FREE(cache_key.data);
                smb_fname_rel->base_name = orig_base_name;
                errno = ENOMEM;
                return -1;
        }

        if (IS_VETO_PATH(dirfsp->conn, smb_fname_rel->base_name)) {
                DBG_DEBUG("veto files rejecting last component %s\n",
                          smb_fname_str_dbg(smb_fname_rel));
                TALLOC_FREE(cache_key.data);
                smb_fname_rel->base_name = orig_base_name;
                errno = EPERM;
                return -1;
        }

        fd = SMB_VFS_OPENAT(conn, dirfsp, smb_fname_rel, fsp, how);
        if (fd >= 0) {
                TALLOC_FREE(cache_key.data);
                return fd;
        }

        memcache_delete(NULL, GETREALFILENAME_CACHE, cache_key);

        /*
         * For the "new filename" case we need to preserve the
         * capitalization the client sent us, see
         * https://bugzilla.samba.org/show_bug.cgi?id=15481
         */
        TALLOC_FREE(smb_fname_rel->base_name);
        smb_fname_rel->base_name = orig_base_name;

lookup:

        status = get_real_filename_at(dirfsp,
                                      orig_base_name,
                                      mem_ctx,
                                      &smb_fname_rel->base_name);
        if (!NT_STATUS_IS_OK(status)) {
                DBG_DEBUG("get_real_filename_at() failed: %s\n",
                          nt_errstr(status));
                errno = ENOENT;
                return -1;
        }

        if (IS_VETO_PATH(conn, smb_fname_rel->base_name)) {
                DBG_DEBUG("found veto files path component "
                          "%s => %s\n",
                          orig_base_name,
                          smb_fname_rel->base_name);
                TALLOC_FREE(smb_fname_rel->base_name);
                smb_fname_rel->base_name = orig_base_name;
                errno = ENOENT;
                return -1;
        }

        fd = SMB_VFS_OPENAT(conn, dirfsp, smb_fname_rel, fsp, how);

        if ((fd >= 0) && (cache_key.data != NULL)) {
                DATA_BLOB value = {
                        .data = (uint8_t *)smb_fname_rel->base_name,
                        .length = strlen(smb_fname_rel->base_name) + 1,
                };

                memcache_add(NULL, GETREALFILENAME_CACHE, cache_key, value);
                TALLOC_FREE(cache_key.data);
        }

        return fd;
}

NTSTATUS openat_pathref_fsp_nosymlink(TALLOC_CTX *mem_ctx,
                                      struct connection_struct *conn,
                                      struct files_struct *in_dirfsp,
                                      const char *path_in,
                                      NTTIME twrp,
                                      bool posix,
                                      struct smb_filename **_smb_fname,
                                      struct open_symlink_err **_symlink_err)
{
        struct files_struct *dirfsp = in_dirfsp;
        struct smb_filename full_fname = {
                .base_name = NULL,
                .twrp = twrp,
                .flags = posix ? SMB_FILENAME_POSIX_PATH : 0,
        };
        struct smb_filename rel_fname = {
                .base_name = NULL,
                .twrp = twrp,
                .flags = full_fname.flags,
        };
        struct smb_filename *result = NULL;
        struct open_symlink_err *symlink_err = NULL;
        struct files_struct *fsp = NULL;
        char *path = NULL, *next = NULL;
        bool ok, is_toplevel;
        int fd;
        NTSTATUS status;
        struct vfs_open_how how = {
                .flags = O_NOFOLLOW | O_NONBLOCK,
                .mode = 0,
        };

        DBG_DEBUG("path_in=%s\n", path_in);

        status = fsp_new(conn, conn, &fsp);
        if (!NT_STATUS_IS_OK(status)) {
                DBG_DEBUG("fsp_new() failed: %s\n", nt_errstr(status));
                goto fail;
        }

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

        fsp->fsp_name = &full_fname;

#ifdef O_PATH
        /*
         * Add O_PATH manually, doing this by setting
         * fsp->fsp_flags.is_pathref will make us become_root() in the
         * non-O_PATH case, which would cause a security problem.
         */
        how.flags |= O_PATH;
#else
#ifdef O_SEARCH
        /*
         * O_SEARCH just checks for the "x" bit. We are traversing
         * directories, so we don't need the implicit O_RDONLY ("r"
         * permissions) but only the "x"-permissions requested by
         * O_SEARCH. We need either O_PATH or O_SEARCH to correctly
         * function, without either we will incorrectly require also
         * the "r" bit when traversing the directory hierarchy.
         */
        how.flags |= O_SEARCH;
#endif
#endif

        is_toplevel = (dirfsp == dirfsp->conn->cwd_fsp);
        is_toplevel |= ISDOT(dirfsp->fsp_name->base_name);

        full_fname.base_name =
                talloc_strdup(talloc_tos(),
                              is_toplevel ? "" : dirfsp->fsp_name->base_name);
        if (full_fname.base_name == NULL) {
                DBG_DEBUG("talloc_strdup() failed\n");
                goto nomem;
        }

        /*
         * First split the path into individual components.
         */
        path = path_to_strv(talloc_tos(), path_in);
        if (path == NULL) {
                DBG_DEBUG("path_to_strv() failed\n");
                goto nomem;
        }

        /*
         * First we loop over all components
         * in order to verify, there's no '.' or '..'
         */
        rel_fname.base_name = path;
        while (rel_fname.base_name != NULL) {

                next = strv_next(path, rel_fname.base_name);

                /*
                 * Path sanitizing further up has cleaned or rejected
                 * empty path components. Assert this here.
                 */
                SMB_ASSERT(rel_fname.base_name[0] != '\0');

                if (ISDOT(rel_fname.base_name) ||
                    ISDOTDOT(rel_fname.base_name)) {
                        DBG_DEBUG("%s contains a dot\n", path_in);
                        status = NT_STATUS_OBJECT_NAME_INVALID;
                        goto fail;
                }

                /* Check veto files. */
                if (IS_VETO_PATH(conn, rel_fname.base_name)) {
                        DBG_DEBUG("%s contains veto files path component %s\n",
                                  path_in, rel_fname.base_name);
                        status = NT_STATUS_OBJECT_PATH_NOT_FOUND;
                        goto fail;
                }

                rel_fname.base_name = next;
        }

        if (conn->open_how_resolve & VFS_OPEN_HOW_RESOLVE_NO_SYMLINKS) {

                /*
                 * Try a direct openat2 with RESOLVE_NO_SYMLINKS to
                 * avoid the openat/close loop further down.
                 */

                rel_fname.base_name = discard_const_p(char, path_in);
                how.resolve = VFS_OPEN_HOW_RESOLVE_NO_SYMLINKS;

                fd = SMB_VFS_OPENAT(conn, dirfsp, &rel_fname, fsp, &how);
                if (fd >= 0) {
                        fsp_set_fd(fsp, fd);
                        ok = full_path_extend(&full_fname.base_name,
                                              rel_fname.base_name);
                        if (!ok) {
                                goto nomem;
                        }
                        goto done;
                }

                status = map_nt_error_from_unix(errno);
                DBG_DEBUG("SMB_VFS_OPENAT(%s, %s, RESOLVE_NO_SYMLINKS) "
                          "returned %d %s => %s\n",
                          smb_fname_str_dbg(dirfsp->fsp_name), path_in,
                          errno, strerror(errno), nt_errstr(status));
                SMB_ASSERT(fd == -1);
                switch (errno) {
                case ENOSYS:
                        /*
                         * We got ENOSYS, so fallback to the old code
                         * if the kernel doesn't support openat2() yet.
                         */
                        break;

                case ELOOP:
                case ENOTDIR:
                        /*
                         * For ELOOP we also fallback in order to
                         * return the correct information with
                         * NT_STATUS_STOPPED_ON_SYMLINK.
                         *
                         * O_NOFOLLOW|O_DIRECTORY results in
                         * ENOTDIR instead of ELOOP for the final
                         * component.
                         */
                        break;

                case ENOENT:
                        /*
                         * If we got ENOENT, the filesystem could
                         * be case sensitive. For now we only do
                         * the get_real_filename_at() dance in
                         * the fallback loop below.
                         */
                        break;

                default:
                        goto fail;
                }

                /*
                 * Just fallback to the openat loop
                 */
                how.resolve = 0;
        }

        /*
         * Now we loop over all components
         * opening each one and using it
         * as dirfd for the next one.
         *
         * It means we can detect symlinks
         * within the path.
         */
        rel_fname.base_name = path;
next:
        next = strv_next(path, rel_fname.base_name);

        fd = smb_vfs_openat_ci(talloc_tos(),
                               posix || conn->case_sensitive,
                               conn,
                               dirfsp,
                               &rel_fname,
                               fsp,
                               &how);

#ifndef O_PATH
        if ((fd == -1) && (errno == ELOOP)) {
                int ret;

                /*
                 * openat() hit a symlink. With O_PATH we open the
                 * symlink and get ENOTDIR in the next round, see
                 * below.
                 */

                status = create_open_symlink_err(mem_ctx,
                                                 dirfsp,
                                                 &rel_fname,
                                                 &symlink_err);
                if (!NT_STATUS_IS_OK(status)) {
                        DBG_DEBUG("create_open_symlink_err failed: %s\n",
                                  nt_errstr(status));
                        goto fail;
                }

                if (next != NULL) {
                        size_t parsed = next - path;
                        size_t len = talloc_get_size(path);
                        symlink_err->unparsed = len - parsed;
                }

                /*
                 * We know rel_fname is a symlink, now fill in the
                 * rest of the metadata for our callers.
                 */

                ret = SMB_VFS_FSTATAT(conn,
                                      dirfsp,
                                      &rel_fname,
                                      &symlink_err->st,
                                      AT_SYMLINK_NOFOLLOW);
                if (ret == -1) {
                        status = map_nt_error_from_unix(errno);
                        DBG_DEBUG("SMB_VFS_FSTATAT(%s/%s) failed: %s\n",
                                  fsp_str_dbg(dirfsp),
                                  rel_fname.base_name,
                                  strerror(errno));
                        TALLOC_FREE(symlink_err);
                        goto fail;
                }

                if (!S_ISLNK(symlink_err->st.st_ex_mode)) {
                        /*
                         * Hit a race: readlink_talloc() worked before
                         * the fstatat(), but rel_fname changed to
                         * something that's not a symlink.
                         */
                        status = NT_STATUS_OBJECT_NAME_NOT_FOUND;
                        TALLOC_FREE(symlink_err);
                        goto fail;
                }

                status = NT_STATUS_STOPPED_ON_SYMLINK;
                goto fail;
        }
#endif

        if ((fd == -1) && (errno == ENOTDIR)) {
                size_t parsed, len;

                /*
                 * dirfsp does not point at a directory, try a
                 * freadlink.
                 */

                status = create_open_symlink_err(mem_ctx,
                                                 dirfsp,
                                                 NULL,
                                                 &symlink_err);

                if (!NT_STATUS_IS_OK(status)) {
                        DBG_DEBUG("create_open_symlink_err failed: %s\n",
                                  nt_errstr(status));
                        status = NT_STATUS_NOT_A_DIRECTORY;
                        goto fail;
                }

                parsed = rel_fname.base_name - path;
                len = talloc_get_size(path);
                symlink_err->unparsed = len - parsed;

                symlink_err->st = dirfsp->fsp_name->st;

                status = NT_STATUS_STOPPED_ON_SYMLINK;
                goto fail;
        }

        if (fd == -1) {
                status = map_nt_error_from_unix(errno);
                DBG_DEBUG("SMB_VFS_OPENAT() failed: %s\n",
                          strerror(errno));
                goto fail;
        }
        fsp_set_fd(fsp, fd);

        ok = full_path_extend(&full_fname.base_name, rel_fname.base_name);
        if (!ok) {
                goto nomem;
        }

        if (next != NULL) {
                struct files_struct *tmp = NULL;

                if (dirfsp != in_dirfsp) {
                        fd_close(dirfsp);
                }

                tmp = dirfsp;
                dirfsp = fsp;

                if (tmp == in_dirfsp) {
                        status = fsp_new(conn, conn, &fsp);
                        if (!NT_STATUS_IS_OK(status)) {
                                DBG_DEBUG("fsp_new() failed: %s\n",
                                          nt_errstr(status));
                                goto fail;
                        }
                        fsp->fsp_name = &full_fname;
                } else {
                        fsp = tmp;
                }

                rel_fname.base_name = next;

                goto next;
        }

        if (dirfsp != in_dirfsp) {
                SMB_ASSERT(fsp_get_pathref_fd(dirfsp) != -1);
                fd_close(dirfsp);
                dirfsp->fsp_name = NULL;
                file_free(NULL, dirfsp);
                dirfsp = NULL;
        }

done:
        fsp->fsp_flags.is_pathref = true;
        fsp->fsp_name = NULL;

        status = fsp_set_smb_fname(fsp, &full_fname);
        if (!NT_STATUS_IS_OK(status)) {
                DBG_DEBUG("fsp_set_smb_fname() failed: %s\n",
                          nt_errstr(status));
                goto fail;
        }

        status = vfs_stat_fsp(fsp);
        if (!NT_STATUS_IS_OK(status)) {
                DBG_DEBUG("vfs_stat_fsp(%s) failed: %s\n",
                          fsp_str_dbg(fsp),
                          nt_errstr(status));
                goto fail;
        }

        if (S_ISLNK(fsp->fsp_name->st.st_ex_mode)) {
                /*
                 * Last component was a symlink we opened with O_PATH, fail it
                 * here.
                 */
                status = create_open_symlink_err(mem_ctx,
                                                 fsp,
                                                 NULL,
                                                 &symlink_err);
                if (!NT_STATUS_IS_OK(status)) {
                        return status;
                }
                symlink_err->st = fsp->fsp_name->st;

                status = NT_STATUS_STOPPED_ON_SYMLINK;
                goto fail;
        }

        /*
         * We must correctly set fsp->file_id as code inside
         * open.c will use this to check if delete_on_close
         * has been set on the dirfsp.
         */
        fsp->file_id = vfs_file_id_from_sbuf(conn, &fsp->fsp_name->st);

        result = cp_smb_filename(mem_ctx, fsp->fsp_name);
        if (result == NULL) {
                DBG_DEBUG("cp_smb_filename() failed\n");
                goto nomem;
        }

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

        *_smb_fname = result;

        DBG_DEBUG("returning %s\n", smb_fname_str_dbg(result));

        return NT_STATUS_OK;

nomem:
        status = NT_STATUS_NO_MEMORY;
fail:
        if (fsp != NULL) {
                if (fsp_get_pathref_fd(fsp) != -1) {
                        fd_close(fsp);
                }
                file_free(NULL, fsp);
                fsp = NULL;
        }

        if ((dirfsp != NULL) && (dirfsp != in_dirfsp)) {
                SMB_ASSERT(fsp_get_pathref_fd(dirfsp) != -1);
                fd_close(dirfsp);
                dirfsp->fsp_name = NULL;
                file_free(NULL, dirfsp);
                dirfsp = NULL;
        }

        if (NT_STATUS_EQUAL(status, NT_STATUS_STOPPED_ON_SYMLINK)) {
                *_symlink_err = symlink_err;
        }

        TALLOC_FREE(path);
        return status;
}

/*
 * Open smb_fname_rel->fsp as a pathref fsp with a case insensitive
 * fallback using GETREALFILENAME_CACHE and get_real_filename_at() if
 * the first attempt based on the filename sent by the client gives
 * ENOENT.
 */
NTSTATUS openat_pathref_fsp_lcomp(struct files_struct *dirfsp,
                                  struct smb_filename *smb_fname_rel,
                                  uint32_t ucf_flags)
{
        struct connection_struct *conn = dirfsp->conn;
        const char *orig_rel_base_name = smb_fname_rel->base_name;
        struct files_struct *fsp = NULL;
        struct smb_filename *full_fname = NULL;
        struct vfs_open_how how = {
                .flags = O_RDONLY | O_NONBLOCK | O_NOFOLLOW,
        };
        NTSTATUS status;
        int ret, fd;

        /*
         * Make sure we don't need of the all the magic in
         * openat_pathref_fsp() with regards non_widelink_open etc.
         */

        SMB_ASSERT((smb_fname_rel->fsp == NULL) &&
                   (dirfsp != dirfsp->conn->cwd_fsp) &&
                   (strchr_m(smb_fname_rel->base_name, '/') == NULL) &&
                   !is_named_stream(smb_fname_rel));

        SET_STAT_INVALID(smb_fname_rel->st);

        /* Check veto files - only looks at last component. */
        if (IS_VETO_PATH(dirfsp->conn, smb_fname_rel->base_name)) {
                DBG_DEBUG("veto files rejecting last component %s\n",
                          smb_fname_str_dbg(smb_fname_rel));
                return NT_STATUS_NETWORK_OPEN_RESTRICTION;
        }

        status = fsp_new(conn, conn, &fsp);
        if (!NT_STATUS_IS_OK(status)) {
                DBG_DEBUG("fsp_new() failed: %s\n", nt_errstr(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(conn, dirfsp, smb_fname_rel);
        if (full_fname == NULL) {
                DBG_DEBUG("full_path_from_dirfsp_atname(%s/%s) failed\n",
                          dirfsp->fsp_name->base_name,
                          smb_fname_rel->base_name);
                file_free(NULL, fsp);
                return NT_STATUS_NO_MEMORY;
        }

        status = fsp_attach_smb_fname(fsp, &full_fname);
        if (!NT_STATUS_IS_OK(status)) {
                DBG_DEBUG("fsp_attach_smb_fname(fsp, %s) failed: %s\n",
                          smb_fname_str_dbg(full_fname),
                          nt_errstr(status));
                file_free(NULL, fsp);
                return status;
        }

        fd = smb_vfs_openat_ci(smb_fname_rel,
                               (ucf_flags & UCF_POSIX_PATHNAMES) ||
                                       conn->case_sensitive,
                               conn,
                               dirfsp,
                               smb_fname_rel,
                               fsp,
                               &how);

        if ((fd == -1) && (errno == ENOENT)) {
                status = map_nt_error_from_unix(errno);
                DBG_DEBUG("smb_vfs_openat(%s/%s) failed: %s\n",
                          dirfsp->fsp_name->base_name,
                          smb_fname_rel->base_name,
                          strerror(errno));
                file_free(NULL, fsp);
                return status;
        }

        if (smb_fname_rel->base_name != orig_rel_base_name) {
                struct smb_filename new_fullname = *smb_fname_rel;

                DBG_DEBUG("rel->base_name changed from %s to %s\n",
                          orig_rel_base_name,
                          smb_fname_rel->base_name);

                new_fullname.base_name = full_path_from_dirfsp_at_basename(
                        talloc_tos(), dirfsp, new_fullname.base_name);
                if (new_fullname.base_name == NULL) {
                        fd_close(fsp);
                        file_free(NULL, fsp);
                        return NT_STATUS_NO_MEMORY;
                }

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

        fsp_set_fd(fsp, fd);

        if (fd >= 0) {
                ret = SMB_VFS_FSTAT(fsp, &fsp->fsp_name->st);
        } else {
                ret = SMB_VFS_FSTATAT(fsp->conn,
                                      dirfsp,
                                      smb_fname_rel,
                                      &fsp->fsp_name->st,
                                      AT_SYMLINK_NOFOLLOW);
        }
        if (ret == -1) {
                status = map_nt_error_from_unix(errno);
                DBG_DEBUG("SMB_VFS_%sSTAT(%s/%s) failed: %s\n",
                          (fd >= 0) ? "F" : "",
                          dirfsp->fsp_name->base_name,
                          smb_fname_rel->base_name,
                          nt_errstr(status));
                fd_close(fsp);
                file_free(NULL, fsp);
                return status;
        }

        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);

        smb_fname_rel->st = fsp->fsp_name->st;

        status = fsp_smb_fname_link(fsp,
                                    &smb_fname_rel->fsp_link,
                                    &smb_fname_rel->fsp);
        if (!NT_STATUS_IS_OK(status)) {
                DBG_DEBUG("fsp_smb_fname_link() failed: %s\n",
                          nt_errstr(status));
                fd_close(fsp);
                file_free(NULL, fsp);
                return status;
        }

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

        talloc_set_destructor(smb_fname_rel, smb_fname_fsp_destructor);
        return NT_STATUS_OK;
}

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;
}

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

NTSTATUS reference_smb_fname_fsp_link(struct smb_filename *smb_fname_dst,
                                      const 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, fsp_ref_no_close_destructor);

        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_NOTICE("opening [%s] failed\n",
                        smb_fname_str_dbg(smb_fname));
                TALLOC_FREE(smb_fname);
                return status;
        }

        *_smb_fname = smb_fname;
        return NT_STATUS_OK;
}

/**
 * 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;
        }

        status = reference_smb_fname_fsp_link(atname, smb_fname);
        if (!NT_STATUS_IS_OK(status)) {
                TALLOC_FREE(parent);
                return status;
        }

        *_parent = parent;
        *_atname = atname;
        return NT_STATUS_OK;
}

static bool close_file_in_loop(struct files_struct *fsp,
                               enum file_close_type close_type)
{
        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, close_type);
                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, close_type);
        return true;
}

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

struct file_close_conn_state {
        struct connection_struct *conn;
        enum file_close_type close_type;
        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, state->close_type);
        if (!did_close) {
                state->fsp_left_behind = true;
        }

        return NULL;
}

void file_close_conn(connection_struct *conn, enum file_close_type close_type)
{
        struct file_close_conn_state state = { .conn = conn,
                                               .close_type = close_type };

        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, SHUTDOWN_CLOSE);
        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);
                }
                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;
        fsp->fsp_name->st.cached_dos_attributes = FILE_ATTRIBUTE_INVALID;
        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;
        }

        fsp->fsp_name->st.cached_dos_attributes = FILE_ATTRIBUTE_INVALID;

        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;
                }
                smb2req->compat_chain_fsp->fsp_name->st.cached_dos_attributes =
                        FILE_ATTRIBUTE_INVALID;
                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(
        files_struct *from,
        uint32_t access_mask,
        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)
{
        TALLOC_CTX *frame = talloc_stackframe();
        struct smb_filename *smb_fname_new = talloc_move(fsp, _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) {
                TALLOC_FREE(frame);
                return NT_STATUS_NO_MEMORY;
        }

        status = file_name_hash(fsp->conn,
                                name_str,
                                &name_hash);
        TALLOC_FREE(frame);
        name_str = NULL;
        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;
        fsp->fsp_name->st.cached_dos_attributes = FILE_ATTRIBUTE_INVALID;
        *_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;

        if ((buf == NULL) || (buflen == 0)) {
                return strlen(fsp->conn->connectpath) + 1 +
                       strlen(fsp->fsp_name->base_name);
        }

        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;
}

static bool fsp_generic_ask_sharemode(struct files_struct *fsp)
{
        if (fsp == NULL) {
                return false;
        }

        if (fsp->posix_flags & FSP_POSIX_FLAGS_PATHNAMES) {
                /* Always use filesystem for UNIX mtime query. */
                return false;
        }

        return true;
}

bool fsp_search_ask_sharemode(struct files_struct *fsp)
{
        if (!fsp_generic_ask_sharemode(fsp)) {
                return false;
        }

        return lp_smbd_search_ask_sharemode(SNUM(fsp->conn));
}

bool fsp_getinfo_ask_sharemode(struct files_struct *fsp)
{
        if (!fsp_generic_ask_sharemode(fsp)) {
                return false;
        }

        return lp_smbd_getinfo_ask_sharemode(SNUM(fsp->conn));
}