smbd/ioctl: add FSCTL_SET_ZERO_DATA support

[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 "libcli/security/security.h"
#include "util_tdb.h"
#include <ccan/hash/hash.h>
#include "lib/util/bitmap.h"

#define FILE_HANDLE_OFFSET 0x1000

/**
 * 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 = talloc_zero(mem_ctx, struct fd_handle);
        if (fsp->fh == NULL) {
                goto fail;
        }

        fsp->fh->ref_count = 1;
        fsp->fh->fd = -1;

        fsp->fnum = FNUM_FIELD_INVALID;
        fsp->conn = conn;

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

        conn->num_files_open++;

        *result = fsp;
        return NT_STATUS_OK;

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

        return status;
}

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

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);

        if (req) {
                struct smbXsrv_connection *xconn = req->xconn;
                struct smbXsrv_open *op = NULL;
                NTTIME now = timeval_to_nttime(&fsp->open_time);

                status = smbXsrv_open_create(xconn,
                                             conn->session_info,
                                             now, &op);
                if (!NT_STATUS_IS_OK(status)) {
                        file_free(NULL, fsp);
                        return status;
                }
                fsp->op = op;
                op->compat = fsp;
                fsp->fnum = op->local_id;
                fsp->fh->gen_id = smbXsrv_open_hash(op);
        } else {
                DEBUG(10, ("%s: req==NULL, INTERNAL_OPEN_ONLY, smbXsrv_open "
                           "allocated\n", __func__));
        }

        /*
         * 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);
        if (fsp->fsp_name == NULL) {
                file_free(NULL, fsp);
                return NT_STATUS_NO_MEMORY;
        }

        DEBUG(5,("allocated file structure %s (%u used)\n",
                 fsp_fnum_dbg(fsp), (unsigned int)sconn->num_files));

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

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

void file_close_conn(connection_struct *conn)
{
        files_struct *fsp, *next;

        for (fsp=conn->sconn->files; fsp; fsp=next) {
                next = fsp->next;
                if (fsp->conn != conn) {
                        continue;
                }
                if (fsp->op != NULL && fsp->op->global->durable) {
                        /*
                         * A tree disconnect closes a durable handle
                         */
                        fsp->op->global->durable = false;
                }
                close_file(NULL, fsp, SHUTDOWN_CLOSE);
        }
}

/****************************************************************************
 Close all open files for a pid and a vuid.
****************************************************************************/

void file_close_pid(struct smbd_server_connection *sconn, uint16 smbpid,
                    uint64_t vuid)
{
        files_struct *fsp, *next;

        for (fsp=sconn->files;fsp;fsp=next) {
                next = fsp->next;
                if ((fsp->file_pid == smbpid) && (fsp->vuid == vuid)) {
                        close_file(NULL, fsp, SHUTDOWN_CLOSE);
                }
        }
}

/****************************************************************************
 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.
****************************************************************************/

void file_close_user(struct smbd_server_connection *sconn, uint64_t vuid)
{
        files_struct *fsp, *next;

        for (fsp=sconn->files; fsp; fsp=next) {
                next=fsp->next;
                if (fsp->vuid == vuid) {
                        close_file(NULL, fsp, SHUTDOWN_CLOSE);
                }
        }
}

/*
 * 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->fh->fd == 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) &&
                    fsp->fh->gen_id == gen_id ) {
                        if (count > 10) {
                                DLIST_PROMOTE(sconn->files, fsp);
                        }
                        /* Paranoia check. */
                        if ((fsp->fh->fd == -1) &&
                            (fsp->oplock_type != NO_OPLOCK &&
                             fsp->oplock_type != LEASE_OPLOCK)) {
                                DEBUG(0,("file_find_dif: file %s file_id = "
                                         "%s, gen = %u oplock_type = %u is a "
                                         "stat open with oplock type !\n",
                                         fsp_str_dbg(fsp),
                                         file_id_string_tos(&fsp->file_id),
                                         (unsigned int)fsp->fh->gen_id,
                                         (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)
{
        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 (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)
{
        files_struct *fsp;

        for (fsp = start_fsp->next;fsp;fsp=fsp->next) {
                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;
}

/****************************************************************************
 Sync open files on a connection.
****************************************************************************/

void file_sync_all(connection_struct *conn)
{
        files_struct *fsp, *next;

        for (fsp=conn->sconn->files; fsp; fsp=next) {
                next=fsp->next;
                if ((conn == fsp->conn) && (fsp->fh->fd != -1)) {
                        sync_file(conn, fsp, True /* write through */);
                }
        }
}

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

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

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

        TALLOC_FREE(fsp->fake_file_handle);

        if (fsp->fh->ref_count == 1) {
                TALLOC_FREE(fsp->fh);
        } else {
                fsp->fh->ref_count--;
        }

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

        fsp->conn->num_files_open--;

        /* 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);
}

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

        if (fsp->notify) {
                struct notify_context *notify_ctx =
                        fsp->conn->sconn->notify_ctx;
                notify_remove(notify_ctx, fsp);
                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.
         */
        if (req != NULL && req->smb2req) {
                remove_smb2_chained_fsp(fsp);
        }

        /* Closing a file can invalidate the positive cache. */
        if (fsp == sconn->fsp_fi_cache.fsp) {
                ZERO_STRUCT(sconn->fsp_fi_cache);
        }

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

        fsp_free(fsp);

        DEBUG(5,("freed files structure %llu (%u used)\n",
                 (unsigned long long)fnum, (unsigned int)sconn->num_files));
}

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

files_struct *file_fsp(struct smb_request *req, uint16 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->deferred_close) {
                        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->deferred_close) {
                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->compat == NULL) {
                return NULL;
        }

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

        if (fsp->deferred_close) {
                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->deferred_close) {
                        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 access_mask, uint32 share_access,
                      uint32 create_options, files_struct *to)
{
        /* this can never happen for print files */
        SMB_ASSERT(from->print_file == NULL);

        TALLOC_FREE(to->fh);

        to->fh = from->fh;
        to->fh->ref_count++;

        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->share_access = share_access;
        to->oplock_type = from->oplock_type;
        to->can_lock = from->can_lock;
        to->can_read = ((access_mask & FILE_READ_DATA) != 0);
        to->can_write =
                CAN_WRITE(from->conn) &&
                ((access_mask & (FILE_WRITE_DATA | FILE_APPEND_DATA)) != 0);
        to->modified = from->modified;
        to->is_directory = from->is_directory;
        to->aio_write_behind = from->aio_write_behind;

        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;

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

        len = full_path_tos(conn->connectpath, name, tmpbuf, sizeof(tmpbuf),
                            &fullpath, &to_free);
        if (len == -1) {
                return NT_STATUS_NO_MEMORY;
        }
        *p_name_hash = hash(fullpath, len+1, 0);

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

        TALLOC_FREE(to_free);
        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_new;

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

        TALLOC_FREE(fsp->fsp_name);
        fsp->fsp_name = smb_fname_new;

        return file_name_hash(fsp->conn,
                        smb_fname_str_dbg(fsp->fsp_name),
                        &fsp->name_hash);
}

const struct GUID *fsp_client_guid(const files_struct *fsp)
{
        return &fsp->conn->sconn->client->connections->smb2.client.guid;
}

uint32_t fsp_lease_type(struct files_struct *fsp)
{
        if (fsp->oplock_type == LEASE_OPLOCK) {
                return fsp->lease->lease.lease_state;
        }
        return map_oplock_to_lease_type(fsp->oplock_type);
}