s3: Remove some references to smbd_messaging_context()

[Samba/gebeck_regimport.git] / source3 / rpc_server / srv_pipe_hnd.c

/*
 *  Unix SMB/CIFS implementation.
 *  RPC Pipe client / server routines
 *  Copyright (C) Andrew Tridgell              1992-1998,
 *  Largely re-written : 2005
 *  Copyright (C) Jeremy Allison                1998 - 2005
 *
 *  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 "../librpc/gen_ndr/srv_spoolss.h"
#include "librpc/gen_ndr/ndr_named_pipe_auth.h"
#include "../libcli/named_pipe_auth/npa_tstream.h"
#include "rpc_server.h"

#undef DBGC_CLASS
#define DBGC_CLASS DBGC_RPC_SRV

/****************************************************************************
 Ensures we have at least RPC_HEADER_LEN amount of data in the incoming buffer.
****************************************************************************/

static ssize_t fill_rpc_header(struct pipes_struct *p, char *data, size_t data_to_copy)
{
        size_t len_needed_to_complete_hdr =
                MIN(data_to_copy, RPC_HEADER_LEN - p->in_data.pdu.length);

        DEBUG(10, ("fill_rpc_header: data_to_copy = %u, "
                   "len_needed_to_complete_hdr = %u, "
                   "receive_len = %u\n",
                   (unsigned int)data_to_copy,
                   (unsigned int)len_needed_to_complete_hdr,
                   (unsigned int)p->in_data.pdu.length ));

        if (p->in_data.pdu.data == NULL) {
                p->in_data.pdu.data = talloc_array(p, uint8_t, RPC_HEADER_LEN);
        }
        if (p->in_data.pdu.data == NULL) {
                DEBUG(0, ("talloc failed\n"));
                return -1;
        }

        memcpy((char *)&p->in_data.pdu.data[p->in_data.pdu.length],
                data, len_needed_to_complete_hdr);
        p->in_data.pdu.length += len_needed_to_complete_hdr;

        return (ssize_t)len_needed_to_complete_hdr;
}

static bool get_pdu_size(struct pipes_struct *p)
{
        uint16_t frag_len;
        /* the fill_rpc_header() call insures we copy only
         * RPC_HEADER_LEN bytes. If this doesn't match then
         * somethign is very wrong and we can only abort */
        if (p->in_data.pdu.length != RPC_HEADER_LEN) {
                DEBUG(0, ("Unexpected RPC Header size! "
                          "got %d, expected %d)\n",
                          (int)p->in_data.pdu.length,
                          RPC_HEADER_LEN));
                set_incoming_fault(p);
                return false;
        }

        frag_len = dcerpc_get_frag_length(&p->in_data.pdu);

        /* verify it is a reasonable value */
        if ((frag_len < RPC_HEADER_LEN) ||
            (frag_len > RPC_MAX_PDU_FRAG_LEN)) {
                DEBUG(0, ("Unexpected RPC Fragment size! (%d)\n",
                          frag_len));
                set_incoming_fault(p);
                return false;
        }

        p->in_data.pdu_needed_len = frag_len - RPC_HEADER_LEN;

        /* allocate the space needed to fill the pdu */
        p->in_data.pdu.data = talloc_realloc(p, p->in_data.pdu.data,
                                                uint8_t, frag_len);
        if (p->in_data.pdu.data == NULL) {
                DEBUG(0, ("talloc_realloc failed\n"));
                set_incoming_fault(p);
                return false;
        }

        return true;
}

/****************************************************************************
  Call this to free any talloc'ed memory. Do this after processing
  a complete incoming and outgoing request (multiple incoming/outgoing
  PDU's).
****************************************************************************/

static void free_pipe_context(struct pipes_struct *p)
{
        data_blob_free(&p->out_data.frag);
        data_blob_free(&p->out_data.rdata);
        data_blob_free(&p->in_data.data);

        DEBUG(3, ("free_pipe_context: "
                "destroying talloc pool of size %lu\n",
                (unsigned long)talloc_total_size(p->mem_ctx)));
        talloc_free_children(p->mem_ctx);
}

/****************************************************************************
 Accepts incoming data on an rpc pipe. Processes the data in pdu sized units.
****************************************************************************/

static ssize_t process_incoming_data(struct pipes_struct *p, char *data, size_t n)
{
        size_t data_to_copy = MIN(n, RPC_MAX_PDU_FRAG_LEN
                                        - p->in_data.pdu.length);

        DEBUG(10, ("process_incoming_data: Start: pdu.length = %u, "
                   "pdu_needed_len = %u, incoming data = %u\n",
                   (unsigned int)p->in_data.pdu.length,
                   (unsigned int)p->in_data.pdu_needed_len,
                   (unsigned int)n ));

        if(data_to_copy == 0) {
                /*
                 * This is an error - data is being received and there is no
                 * space in the PDU. Free the received data and go into the
                 * fault state.
                 */
                DEBUG(0, ("process_incoming_data: "
                          "No space in incoming pdu buffer. "
                          "Current size = %u incoming data size = %u\n",
                          (unsigned int)p->in_data.pdu.length,
                          (unsigned int)n));
                set_incoming_fault(p);
                return -1;
        }

        /*
         * If we have no data already, wait until we get at least
         * a RPC_HEADER_LEN * number of bytes before we can do anything.
         */

        if ((p->in_data.pdu_needed_len == 0) &&
            (p->in_data.pdu.length < RPC_HEADER_LEN)) {
                /*
                 * Always return here. If we have more data then the RPC_HEADER
                 * will be processed the next time around the loop.
                 */
                return fill_rpc_header(p, data, data_to_copy);
        }

        /*
         * At this point we know we have at least an RPC_HEADER_LEN amount of
         * data stored in p->in_data.pdu.
         */

        /*
         * If pdu_needed_len is zero this is a new pdu.
         * Check how much more data we need, then loop again.
         */
        if (p->in_data.pdu_needed_len == 0) {

                bool ok = get_pdu_size(p);
                if (!ok) {
                        return -1;
                }
                if (p->in_data.pdu_needed_len > 0) {
                        return 0;
                }

                /* If rret == 0 and pdu_needed_len == 0 here we have a PDU
                 * that consists of an RPC_HEADER only. This is a
                 * DCERPC_PKT_SHUTDOWN, DCERPC_PKT_CO_CANCEL or
                 * DCERPC_PKT_ORPHANED pdu type.
                 * Deal with this in process_complete_pdu(). */
        }

        /*
         * Ok - at this point we have a valid RPC_HEADER.
         * Keep reading until we have a full pdu.
         */

        data_to_copy = MIN(data_to_copy, p->in_data.pdu_needed_len);

        /*
         * Copy as much of the data as we need into the p->in_data.pdu buffer.
         * pdu_needed_len becomes zero when we have a complete pdu.
         */

        memcpy((char *)&p->in_data.pdu.data[p->in_data.pdu.length],
                data, data_to_copy);
        p->in_data.pdu.length += data_to_copy;
        p->in_data.pdu_needed_len -= data_to_copy;

        /*
         * Do we have a complete PDU ?
         * (return the number of bytes handled in the call)
         */

        if(p->in_data.pdu_needed_len == 0) {
                process_complete_pdu(p);
                return data_to_copy;
        }

        DEBUG(10, ("process_incoming_data: not a complete PDU yet. "
                   "pdu.length = %u, pdu_needed_len = %u\n",
                   (unsigned int)p->in_data.pdu.length,
                   (unsigned int)p->in_data.pdu_needed_len));

        return (ssize_t)data_to_copy;
}

/****************************************************************************
 Accepts incoming data on an internal rpc pipe.
****************************************************************************/

static ssize_t write_to_internal_pipe(struct pipes_struct *p, char *data, size_t n)
{
        size_t data_left = n;

        while(data_left) {
                ssize_t data_used;

                DEBUG(10, ("write_to_pipe: data_left = %u\n",
                          (unsigned int)data_left));

                data_used = process_incoming_data(p, data, data_left);

                DEBUG(10, ("write_to_pipe: data_used = %d\n",
                           (int)data_used));

                if(data_used < 0) {
                        return -1;
                }

                data_left -= data_used;
                data += data_used;
        }

        return n;
}

/****************************************************************************
 Replies to a request to read data from a pipe.

 Headers are interspersed with the data at PDU intervals. By the time
 this function is called, the start of the data could possibly have been
 read by an SMBtrans (file_offset != 0).

 Calling create_rpc_reply() here is a hack. The data should already
 have been prepared into arrays of headers + data stream sections.
****************************************************************************/

static ssize_t read_from_internal_pipe(struct pipes_struct *p, char *data,
                                       size_t n, bool *is_data_outstanding)
{
        uint32 pdu_remaining = 0;
        ssize_t data_returned = 0;

        if (!p) {
                DEBUG(0,("read_from_pipe: pipe not open\n"));
                return -1;
        }

        DEBUG(6,(" name: %s len: %u\n",
                 get_pipe_name_from_syntax(talloc_tos(), &p->syntax),
                 (unsigned int)n));

        /*
         * We cannot return more than one PDU length per
         * read request.
         */

        /*
         * This condition should result in the connection being closed.
         * Netapp filers seem to set it to 0xffff which results in domain
         * authentications failing.  Just ignore it so things work.
         */

        if(n > RPC_MAX_PDU_FRAG_LEN) {
                DEBUG(5,("read_from_pipe: too large read (%u) requested on "
                         "pipe %s. We can only service %d sized reads.\n",
                         (unsigned int)n,
                         get_pipe_name_from_syntax(talloc_tos(), &p->syntax),
                         RPC_MAX_PDU_FRAG_LEN ));
                n = RPC_MAX_PDU_FRAG_LEN;
        }

        /*
         * Determine if there is still data to send in the
         * pipe PDU buffer. Always send this first. Never
         * send more than is left in the current PDU. The
         * client should send a new read request for a new
         * PDU.
         */

        pdu_remaining = p->out_data.frag.length
                - p->out_data.current_pdu_sent;

        if (pdu_remaining > 0) {
                data_returned = (ssize_t)MIN(n, pdu_remaining);

                DEBUG(10,("read_from_pipe: %s: current_pdu_len = %u, "
                          "current_pdu_sent = %u returning %d bytes.\n",
                          get_pipe_name_from_syntax(talloc_tos(), &p->syntax),
                          (unsigned int)p->out_data.frag.length,
                          (unsigned int)p->out_data.current_pdu_sent,
                          (int)data_returned));

                memcpy(data,
                       p->out_data.frag.data
                       + p->out_data.current_pdu_sent,
                       data_returned);

                p->out_data.current_pdu_sent += (uint32)data_returned;
                goto out;
        }

        /*
         * At this point p->current_pdu_len == p->current_pdu_sent (which
         * may of course be zero if this is the first return fragment.
         */

        DEBUG(10,("read_from_pipe: %s: fault_state = %d : data_sent_length "
                  "= %u, p->out_data.rdata.length = %u.\n",
                  get_pipe_name_from_syntax(talloc_tos(), &p->syntax),
                  (int)p->fault_state,
                  (unsigned int)p->out_data.data_sent_length,
                  (unsigned int)p->out_data.rdata.length));

        if (p->out_data.data_sent_length >= p->out_data.rdata.length) {
                /*
                 * We have sent all possible data, return 0.
                 */
                data_returned = 0;
                goto out;
        }

        /*
         * We need to create a new PDU from the data left in p->rdata.
         * Create the header/data/footers. This also sets up the fields
         * p->current_pdu_len, p->current_pdu_sent, p->data_sent_length
         * and stores the outgoing PDU in p->current_pdu.
         */

        if(!create_next_pdu(p)) {
                DEBUG(0,("read_from_pipe: %s: create_next_pdu failed.\n",
                         get_pipe_name_from_syntax(talloc_tos(), &p->syntax)));
                return -1;
        }

        data_returned = MIN(n, p->out_data.frag.length);

        memcpy(data, p->out_data.frag.data, (size_t)data_returned);
        p->out_data.current_pdu_sent += (uint32)data_returned;

  out:
        (*is_data_outstanding) = p->out_data.frag.length > n;

        if (p->out_data.current_pdu_sent == p->out_data.frag.length) {
                /* We've returned everything in the out_data.frag
                 * so we're done with this pdu. Free it and reset
                 * current_pdu_sent. */
                p->out_data.current_pdu_sent = 0;
                data_blob_free(&p->out_data.frag);

                if (p->out_data.data_sent_length >= p->out_data.rdata.length) {
                        /*
                         * We're completely finished with both outgoing and
                         * incoming data streams. It's safe to free all
                         * temporary data from this request.
                         */
                        free_pipe_context(p);
                }
        }

        return data_returned;
}

bool fsp_is_np(struct files_struct *fsp)
{
        enum FAKE_FILE_TYPE type;

        if ((fsp == NULL) || (fsp->fake_file_handle == NULL)) {
                return false;
        }

        type = fsp->fake_file_handle->type;

        return ((type == FAKE_FILE_TYPE_NAMED_PIPE)
                || (type == FAKE_FILE_TYPE_NAMED_PIPE_PROXY));
}

struct np_proxy_state {
        uint16_t file_type;
        uint16_t device_state;
        uint64_t allocation_size;
        struct tstream_context *npipe;
        struct tevent_queue *read_queue;
        struct tevent_queue *write_queue;
};

static struct np_proxy_state *make_external_rpc_pipe_p(TALLOC_CTX *mem_ctx,
                                const char *pipe_name,
                                const struct tsocket_address *local_address,
                                const struct tsocket_address *remote_address,
                                struct auth_serversupplied_info *server_info)
{
        struct np_proxy_state *result;
        char *socket_np_dir;
        const char *socket_dir;
        struct tevent_context *ev;
        struct tevent_req *subreq;
        struct netr_SamInfo3 *info3;
        NTSTATUS status;
        bool ok;
        int ret;
        int sys_errno;

        result = talloc(mem_ctx, struct np_proxy_state);
        if (result == NULL) {
                DEBUG(0, ("talloc failed\n"));
                return NULL;
        }

        result->read_queue = tevent_queue_create(result, "np_read");
        if (result->read_queue == NULL) {
                DEBUG(0, ("tevent_queue_create failed\n"));
                goto fail;
        }

        result->write_queue = tevent_queue_create(result, "np_write");
        if (result->write_queue == NULL) {
                DEBUG(0, ("tevent_queue_create failed\n"));
                goto fail;
        }

        ev = s3_tevent_context_init(talloc_tos());
        if (ev == NULL) {
                DEBUG(0, ("s3_tevent_context_init failed\n"));
                goto fail;
        }

        socket_dir = lp_parm_const_string(
                GLOBAL_SECTION_SNUM, "external_rpc_pipe", "socket_dir",
                get_dyn_NCALRPCDIR());
        if (socket_dir == NULL) {
                DEBUG(0, ("externan_rpc_pipe:socket_dir not set\n"));
                goto fail;
        }
        socket_np_dir = talloc_asprintf(talloc_tos(), "%s/np", socket_dir);
        if (socket_np_dir == NULL) {
                DEBUG(0, ("talloc_asprintf failed\n"));
                goto fail;
        }

        info3 = talloc_zero(talloc_tos(), struct netr_SamInfo3);
        if (info3 == NULL) {
                DEBUG(0, ("talloc failed\n"));
                goto fail;
        }

        status = serverinfo_to_SamInfo3(server_info, NULL, 0, info3);
        if (!NT_STATUS_IS_OK(status)) {
                TALLOC_FREE(info3);
                DEBUG(0, ("serverinfo_to_SamInfo3 failed: %s\n",
                          nt_errstr(status)));
                goto fail;
        }

        become_root();
        subreq = tstream_npa_connect_send(talloc_tos(), ev,
                                          socket_np_dir,
                                          pipe_name,
                                          remote_address, /* client_addr */
                                          NULL, /* client_name */
                                          local_address, /* server_addr */
                                          NULL, /* server_name */
                                          info3,
                                          server_info->user_session_key,
                                          data_blob_null /* delegated_creds */);
        if (subreq == NULL) {
                unbecome_root();
                DEBUG(0, ("tstream_npa_connect_send to %s for pipe %s and "
                          "user %s\\%s failed\n",
                          socket_np_dir, pipe_name, info3->base.domain.string,
                          info3->base.account_name.string));
                goto fail;
        }
        ok = tevent_req_poll(subreq, ev);
        unbecome_root();
        if (!ok) {
                DEBUG(0, ("tevent_req_poll to %s for pipe %s and user %s\\%s "
                          "failed for tstream_npa_connect: %s\n",
                          socket_np_dir, pipe_name, info3->base.domain.string,
                          info3->base.account_name.string,
                          strerror(errno)));
                goto fail;

        }
        ret = tstream_npa_connect_recv(subreq, &sys_errno,
                                       result,
                                       &result->npipe,
                                       &result->file_type,
                                       &result->device_state,
                                       &result->allocation_size);
        TALLOC_FREE(subreq);
        if (ret != 0) {
                DEBUG(0, ("tstream_npa_connect_recv  to %s for pipe %s and "
                          "user %s\\%s failed: %s\n",
                          socket_np_dir, pipe_name, info3->base.domain.string,
                          info3->base.account_name.string,
                          strerror(sys_errno)));
                goto fail;
        }

        return result;

 fail:
        TALLOC_FREE(result);
        return NULL;
}

NTSTATUS np_open(TALLOC_CTX *mem_ctx, const char *name,
                 const struct tsocket_address *local_address,
                 const struct tsocket_address *remote_address,
                 struct auth_serversupplied_info *server_info,
                 struct fake_file_handle **phandle)
{
        const char **proxy_list;
        struct fake_file_handle *handle;

        proxy_list = lp_parm_string_list(-1, "np", "proxy", NULL);

        handle = talloc(mem_ctx, struct fake_file_handle);
        if (handle == NULL) {
                return NT_STATUS_NO_MEMORY;
        }

        if ((proxy_list != NULL) && str_list_check_ci(proxy_list, name)) {
                struct np_proxy_state *p;

                p = make_external_rpc_pipe_p(handle, name,
                                             local_address,
                                             remote_address,
                                             server_info);

                handle->type = FAKE_FILE_TYPE_NAMED_PIPE_PROXY;
                handle->private_data = p;
        } else {
                struct pipes_struct *p;
                struct ndr_syntax_id syntax;
                const char *client_address;

                if (!is_known_pipename(name, &syntax)) {
                        TALLOC_FREE(handle);
                        return NT_STATUS_OBJECT_NAME_NOT_FOUND;
                }

                if (tsocket_address_is_inet(remote_address, "ip")) {
                        client_address = tsocket_address_inet_addr_string(
                                                remote_address,
                                                talloc_tos());
                        if (client_address == NULL) {
                                TALLOC_FREE(handle);
                                return NT_STATUS_NO_MEMORY;
                        }
                } else {
                        client_address = "";
                }

                p = make_internal_rpc_pipe_p(handle, &syntax, client_address,
                                             server_info);

                handle->type = FAKE_FILE_TYPE_NAMED_PIPE;
                handle->private_data = p;
        }

        if (handle->private_data == NULL) {
                TALLOC_FREE(handle);
                return NT_STATUS_PIPE_NOT_AVAILABLE;
        }

        *phandle = handle;

        return NT_STATUS_OK;
}

bool np_read_in_progress(struct fake_file_handle *handle)
{
        if (handle->type == FAKE_FILE_TYPE_NAMED_PIPE) {
                return false;
        }

        if (handle->type == FAKE_FILE_TYPE_NAMED_PIPE_PROXY) {
                struct np_proxy_state *p = talloc_get_type_abort(
                        handle->private_data, struct np_proxy_state);
                size_t read_count;

                read_count = tevent_queue_length(p->read_queue);
                if (read_count > 0) {
                        return true;
                }

                return false;
        }

        return false;
}

struct np_write_state {
        struct event_context *ev;
        struct np_proxy_state *p;
        struct iovec iov;
        ssize_t nwritten;
};

static void np_write_done(struct tevent_req *subreq);

struct tevent_req *np_write_send(TALLOC_CTX *mem_ctx, struct event_context *ev,
                                 struct fake_file_handle *handle,
                                 const uint8_t *data, size_t len)
{
        struct tevent_req *req;
        struct np_write_state *state;
        NTSTATUS status;

        DEBUG(6, ("np_write_send: len: %d\n", (int)len));
        dump_data(50, data, len);

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

        if (len == 0) {
                state->nwritten = 0;
                status = NT_STATUS_OK;
                goto post_status;
        }

        if (handle->type == FAKE_FILE_TYPE_NAMED_PIPE) {
                struct pipes_struct *p = talloc_get_type_abort(
                        handle->private_data, struct pipes_struct);

                state->nwritten = write_to_internal_pipe(p, (char *)data, len);

                status = (state->nwritten >= 0)
                        ? NT_STATUS_OK : NT_STATUS_UNEXPECTED_IO_ERROR;
                goto post_status;
        }

        if (handle->type == FAKE_FILE_TYPE_NAMED_PIPE_PROXY) {
                struct np_proxy_state *p = talloc_get_type_abort(
                        handle->private_data, struct np_proxy_state);
                struct tevent_req *subreq;

                state->ev = ev;
                state->p = p;
                state->iov.iov_base = CONST_DISCARD(void *, data);
                state->iov.iov_len = len;

                subreq = tstream_writev_queue_send(state, ev,
                                                   p->npipe,
                                                   p->write_queue,
                                                   &state->iov, 1);
                if (subreq == NULL) {
                        goto fail;
                }
                tevent_req_set_callback(subreq, np_write_done, req);
                return req;
        }

        status = NT_STATUS_INVALID_HANDLE;
 post_status:
        if (NT_STATUS_IS_OK(status)) {
                tevent_req_done(req);
        } else {
                tevent_req_nterror(req, status);
        }
        return tevent_req_post(req, ev);
 fail:
        TALLOC_FREE(req);
        return NULL;
}

static void np_write_done(struct tevent_req *subreq)
{
        struct tevent_req *req = tevent_req_callback_data(
                subreq, struct tevent_req);
        struct np_write_state *state = tevent_req_data(
                req, struct np_write_state);
        ssize_t received;
        int err;

        received = tstream_writev_queue_recv(subreq, &err);
        if (received < 0) {
                tevent_req_nterror(req, map_nt_error_from_unix(err));
                return;
        }
        state->nwritten = received;
        tevent_req_done(req);
}

NTSTATUS np_write_recv(struct tevent_req *req, ssize_t *pnwritten)
{
        struct np_write_state *state = tevent_req_data(
                req, struct np_write_state);
        NTSTATUS status;

        if (tevent_req_is_nterror(req, &status)) {
                return status;
        }
        *pnwritten = state->nwritten;
        return NT_STATUS_OK;
}

struct np_ipc_readv_next_vector_state {
        uint8_t *buf;
        size_t len;
        off_t ofs;
        size_t remaining;
};

static void np_ipc_readv_next_vector_init(struct np_ipc_readv_next_vector_state *s,
                                          uint8_t *buf, size_t len)
{
        ZERO_STRUCTP(s);

        s->buf = buf;
        s->len = MIN(len, UINT16_MAX);
}

static int np_ipc_readv_next_vector(struct tstream_context *stream,
                                    void *private_data,
                                    TALLOC_CTX *mem_ctx,
                                    struct iovec **_vector,
                                    size_t *count)
{
        struct np_ipc_readv_next_vector_state *state =
                (struct np_ipc_readv_next_vector_state *)private_data;
        struct iovec *vector;
        ssize_t pending;
        size_t wanted;

        if (state->ofs == state->len) {
                *_vector = NULL;
                *count = 0;
                return 0;
        }

        pending = tstream_pending_bytes(stream);
        if (pending == -1) {
                return -1;
        }

        if (pending == 0 && state->ofs != 0) {
                /* return a short read */
                *_vector = NULL;
                *count = 0;
                return 0;
        }

        if (pending == 0) {
                /* we want at least one byte and recheck again */
                wanted = 1;
        } else {
                size_t missing = state->len - state->ofs;
                if (pending > missing) {
                        /* there's more available */
                        state->remaining = pending - missing;
                        wanted = missing;
                } else {
                        /* read what we can get and recheck in the next cycle */
                        wanted = pending;
                }
        }

        vector = talloc_array(mem_ctx, struct iovec, 1);
        if (!vector) {
                return -1;
        }

        vector[0].iov_base = state->buf + state->ofs;
        vector[0].iov_len = wanted;

        state->ofs += wanted;

        *_vector = vector;
        *count = 1;
        return 0;
}

struct np_read_state {
        struct np_proxy_state *p;
        struct np_ipc_readv_next_vector_state next_vector;

        size_t nread;
        bool is_data_outstanding;
};

static void np_read_done(struct tevent_req *subreq);

struct tevent_req *np_read_send(TALLOC_CTX *mem_ctx, struct event_context *ev,
                                struct fake_file_handle *handle,
                                uint8_t *data, size_t len)
{
        struct tevent_req *req;
        struct np_read_state *state;
        NTSTATUS status;

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

        if (handle->type == FAKE_FILE_TYPE_NAMED_PIPE) {
                struct pipes_struct *p = talloc_get_type_abort(
                        handle->private_data, struct pipes_struct);

                state->nread = read_from_internal_pipe(
                        p, (char *)data, len, &state->is_data_outstanding);

                status = (state->nread >= 0)
                        ? NT_STATUS_OK : NT_STATUS_UNEXPECTED_IO_ERROR;
                goto post_status;
        }

        if (handle->type == FAKE_FILE_TYPE_NAMED_PIPE_PROXY) {
                struct np_proxy_state *p = talloc_get_type_abort(
                        handle->private_data, struct np_proxy_state);
                struct tevent_req *subreq;

                np_ipc_readv_next_vector_init(&state->next_vector,
                                              data, len);

                subreq = tstream_readv_pdu_queue_send(state,
                                                      ev,
                                                      p->npipe,
                                                      p->read_queue,
                                                      np_ipc_readv_next_vector,
                                                      &state->next_vector);
                if (subreq == NULL) {

                }
                tevent_req_set_callback(subreq, np_read_done, req);
                return req;
        }

        status = NT_STATUS_INVALID_HANDLE;
 post_status:
        if (NT_STATUS_IS_OK(status)) {
                tevent_req_done(req);
        } else {
                tevent_req_nterror(req, status);
        }
        return tevent_req_post(req, ev);
}

static void np_read_done(struct tevent_req *subreq)
{
        struct tevent_req *req = tevent_req_callback_data(
                subreq, struct tevent_req);
        struct np_read_state *state = tevent_req_data(
                req, struct np_read_state);
        ssize_t ret;
        int err;

        ret = tstream_readv_pdu_queue_recv(subreq, &err);
        TALLOC_FREE(subreq);
        if (ret == -1) {
                tevent_req_nterror(req, map_nt_error_from_unix(err));
                return;
        }

        state->nread = ret;
        state->is_data_outstanding = (state->next_vector.remaining > 0);

        tevent_req_done(req);
        return;
}

NTSTATUS np_read_recv(struct tevent_req *req, ssize_t *nread,
                      bool *is_data_outstanding)
{
        struct np_read_state *state = tevent_req_data(
                req, struct np_read_state);
        NTSTATUS status;

        if (tevent_req_is_nterror(req, &status)) {
                return status;
        }
        *nread = state->nread;
        *is_data_outstanding = state->is_data_outstanding;
        return NT_STATUS_OK;
}

/**
 * @brief Create a new RPC client context which uses a local dispatch function.
 *
 * @param[in]  conn  The connection struct that will hold the pipe
 *
 * @param[out] spoolss_pipe  A pointer to the connected rpc client pipe.
 *
 * @return              NT_STATUS_OK on success, a corresponding NT status if an
 *                      error occured.
 */
NTSTATUS rpc_connect_spoolss_pipe(connection_struct *conn,
                                  struct rpc_pipe_client **spoolss_pipe)
{
        NTSTATUS status;

        /* TODO: check and handle disconnections */

        if (!conn->spoolss_pipe) {
                status = rpc_pipe_open_internal(conn,
                                                &ndr_table_spoolss.syntax_id,
                                                conn->server_info,
                                                &conn->spoolss_pipe);
                if (!NT_STATUS_IS_OK(status)) {
                        return status;
                }
        }

        *spoolss_pipe = conn->spoolss_pipe;
        return NT_STATUS_OK;
}