source: branches/samba-3.2.x/source/libsmb/clireadwrite.c

/*
   Unix SMB/CIFS implementation.
   client file read/write routines
   Copyright (C) Andrew Tridgell 1994-1998

   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"

/****************************************************************************
  Calculate the recommended read buffer size
****************************************************************************/
static size_t cli_read_max_bufsize(struct cli_state *cli)
{
        if (!client_is_signing_on(cli) && !cli_encryption_on(cli)
            && (cli->posix_capabilities & CIFS_UNIX_LARGE_READ_CAP)) {
                return CLI_SAMBA_MAX_POSIX_LARGE_READX_SIZE;
        }
        if (cli->capabilities & CAP_LARGE_READX) {
                return cli->is_samba
                        ? CLI_SAMBA_MAX_LARGE_READX_SIZE
                        : CLI_WINDOWS_MAX_LARGE_READX_SIZE;
        }
        return (cli->max_xmit - (smb_size+32)) & ~1023;
}

/*
 * Send a read&x request
 */

struct async_req *cli_read_andx_send(TALLOC_CTX *mem_ctx,
                                     struct cli_state *cli, int fnum,
                                     off_t offset, size_t size)
{
        struct async_req *result;
        struct cli_request *req;
        bool bigoffset = False;
        char *enc_buf;

        if (size > cli_read_max_bufsize(cli)) {
                DEBUG(0, ("cli_read_andx_send got size=%d, can only handle "
                          "size=%d\n", (int)size,
                          (int)cli_read_max_bufsize(cli)));
                return NULL;
        }

        result = cli_request_new(mem_ctx, cli->event_ctx, cli, 12, 0, &req);
        if (result == NULL) {
                DEBUG(0, ("cli_request_new failed\n"));
                return NULL;
        }

        req = cli_request_get(result);

        req->data.read.ofs = offset;
        req->data.read.size = size;
        req->data.read.received = 0;
        req->data.read.rcvbuf = NULL;

        if ((SMB_BIG_UINT)offset >> 32)
                bigoffset = True;

        cli_set_message(req->outbuf, bigoffset ? 12 : 10, 0, False);

        SCVAL(req->outbuf,smb_com,SMBreadX);
        SSVAL(req->outbuf,smb_tid,cli->cnum);
        cli_setup_packet_buf(cli, req->outbuf);

        SCVAL(req->outbuf,smb_vwv0,0xFF);
        SCVAL(req->outbuf,smb_vwv0+1,0);
        SSVAL(req->outbuf,smb_vwv1,0);
        SSVAL(req->outbuf,smb_vwv2,fnum);
        SIVAL(req->outbuf,smb_vwv3,offset);
        SSVAL(req->outbuf,smb_vwv5,size);
        SSVAL(req->outbuf,smb_vwv6,size);
        SSVAL(req->outbuf,smb_vwv7,(size >> 16));
        SSVAL(req->outbuf,smb_vwv8,0);
        SSVAL(req->outbuf,smb_vwv9,0);
        SSVAL(req->outbuf,smb_mid,req->mid);

        if (bigoffset) {
                SIVAL(req->outbuf, smb_vwv10,
                      (((SMB_BIG_UINT)offset)>>32) & 0xffffffff);
        }

        cli_calculate_sign_mac(cli, req->outbuf);

        event_fd_set_writeable(cli->fd_event);

        if (cli_encryption_on(cli)) {
                NTSTATUS status;
                status = cli_encrypt_message(cli, req->outbuf, &enc_buf);
                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(0, ("Error in encrypting client message. "
                                  "Error %s\n", nt_errstr(status)));
                        TALLOC_FREE(req);
                        return NULL;
                }
                req->outbuf = enc_buf;
                req->enc_state = cli->trans_enc_state;
        }

        return result;
}

/*
 * Pull the data out of a finished async read_and_x request. rcvbuf is
 * talloced from the request, so better make sure that you copy it away before
 * you talloc_free(req). "rcvbuf" is NOT a talloc_ctx of its own, so do not
 * talloc_move it!
 */

NTSTATUS cli_read_andx_recv(struct async_req *req, ssize_t *received,
                            uint8_t **rcvbuf)
{
        struct cli_request *cli_req = cli_request_get(req);
        NTSTATUS status;
        size_t size;

        SMB_ASSERT(req->state >= ASYNC_REQ_DONE);
        if (req->state == ASYNC_REQ_ERROR) {
                return req->status;
        }

        status = cli_pull_error(cli_req->inbuf);

        if (NT_STATUS_IS_ERR(status)) {
                return status;
        }

        /* size is the number of bytes the server returned.
         * Might be zero. */
        size = SVAL(cli_req->inbuf, smb_vwv5);
        size |= (((unsigned int)(SVAL(cli_req->inbuf, smb_vwv7))) << 16);

        if (size > cli_req->data.read.size) {
                DEBUG(5,("server returned more than we wanted!\n"));
                return NT_STATUS_UNEXPECTED_IO_ERROR;
        }

        *rcvbuf = (uint8_t *)
                (smb_base(cli_req->inbuf) + SVAL(cli_req->inbuf, smb_vwv6));
        *received = size;
        return NT_STATUS_OK;
}

/*
 * Parallel read support.
 *
 * cli_pull sends as many read&x requests as the server would allow via
 * max_mux at a time. When replies flow back in, the data is written into
 * the callback function "sink" in the right order.
 */

struct cli_pull_state {
        struct async_req *req;

        struct cli_state *cli;
        uint16_t fnum;
        off_t start_offset;
        SMB_OFF_T size;

        NTSTATUS (*sink)(char *buf, size_t n, void *priv);
        void *priv;

        size_t chunk_size;

        /*
         * Outstanding requests
         */
        int num_reqs;
        struct async_req **reqs;

        /*
         * For how many bytes did we send requests already?
         */
        SMB_OFF_T requested;

        /*
         * Next request index to push into "sink". This walks around the "req"
         * array, taking care that the requests are pushed to "sink" in the
         * right order. If necessary (i.e. replies don't come in in the right
         * order), replies are held back in "reqs".
         */
        int top_req;

        /*
         * How many bytes did we push into "sink"?
         */

        SMB_OFF_T pushed;
};

static char *cli_pull_print(TALLOC_CTX *mem_ctx, struct async_req *req)
{
        struct cli_pull_state *state = talloc_get_type_abort(
                req->private_data, struct cli_pull_state);
        char *result;

        result = async_req_print(mem_ctx, req);
        if (result == NULL) {
                return NULL;
        }

        return talloc_asprintf_append_buffer(
                result, "num_reqs=%d, top_req=%d",
                state->num_reqs, state->top_req);
}

static void cli_pull_read_done(struct async_req *read_req);

/*
 * Prepare an async pull request
 */

struct async_req *cli_pull_send(TALLOC_CTX *mem_ctx, struct cli_state *cli,
                                uint16_t fnum, off_t start_offset,
                                SMB_OFF_T size, size_t window_size,
                                NTSTATUS (*sink)(char *buf, size_t n,
                                                 void *priv),
                                void *priv)
{
        struct async_req *result;
        struct cli_pull_state *state;
        int i;

        result = async_req_new(mem_ctx, cli->event_ctx);
        if (result == NULL) {
                goto failed;
        }
        state = talloc(result, struct cli_pull_state);
        if (state == NULL) {
                goto failed;
        }
        result->private_data = state;
        result->print = cli_pull_print;
        state->req = result;

        state->cli = cli;
        state->fnum = fnum;
        state->start_offset = start_offset;
        state->size = size;
        state->sink = sink;
        state->priv = priv;

        state->pushed = 0;
        state->top_req = 0;

        if (size == 0) {
                if (!async_post_status(result, NT_STATUS_OK)) {
                        goto failed;
                }
                return result;
        }

        state->chunk_size = cli_read_max_bufsize(cli);

        state->num_reqs = MAX(window_size/state->chunk_size, 1);
        state->num_reqs = MIN(state->num_reqs, cli->max_mux);

        state->reqs = TALLOC_ZERO_ARRAY(state, struct async_req *,
                                        state->num_reqs);
        if (state->reqs == NULL) {
                goto failed;
        }

        state->requested = 0;

        for (i=0; i<state->num_reqs; i++) {
                SMB_OFF_T size_left;
                size_t request_thistime;

                if (state->requested >= size) {
                        state->num_reqs = i;
                        break;
                }

                size_left = size - state->requested;
                request_thistime = MIN(size_left, state->chunk_size);

                state->reqs[i] = cli_read_andx_send(
                        state->reqs, cli, fnum,
                        state->start_offset + state->requested,
                        request_thistime);

                if (state->reqs[i] == NULL) {
                        goto failed;
                }

                state->reqs[i]->async.fn = cli_pull_read_done;
                state->reqs[i]->async.priv = result;

                state->requested += request_thistime;
        }
        return result;

failed:
        TALLOC_FREE(result);
        return NULL;
}

/*
 * Handle incoming read replies, push the data into sink and send out new
 * requests if necessary.
 */

static void cli_pull_read_done(struct async_req *read_req)
{
        struct async_req *pull_req = talloc_get_type_abort(
                read_req->async.priv, struct async_req);
        struct cli_pull_state *state = talloc_get_type_abort(
                pull_req->private_data, struct cli_pull_state);
        struct cli_request *read_state = cli_request_get(read_req);
        NTSTATUS status;

        status = cli_read_andx_recv(read_req, &read_state->data.read.received,
                                    &read_state->data.read.rcvbuf);
        if (!NT_STATUS_IS_OK(status)) {
                async_req_error(state->req, status);
                return;
        }

        /*
         * This loop is the one to take care of out-of-order replies. All
         * pending requests are in state->reqs, state->reqs[top_req] is the
         * one that is to be pushed next. If however a request later than
         * top_req is replied to, then we can't push yet. If top_req is
         * replied to at a later point then, we need to push all the finished
         * requests.
         */

        while (state->reqs[state->top_req] != NULL) {
                struct cli_request *top_read;

                DEBUG(11, ("cli_pull_read_done: top_req = %d\n",
                           state->top_req));

                if (state->reqs[state->top_req]->state < ASYNC_REQ_DONE) {
                        DEBUG(11, ("cli_pull_read_done: top request not yet "
                                   "done\n"));
                        return;
                }

                top_read = cli_request_get(state->reqs[state->top_req]);

                DEBUG(10, ("cli_pull_read_done: Pushing %d bytes, %d already "
                           "pushed\n", (int)top_read->data.read.received,
                           (int)state->pushed));

                status = state->sink((char *)top_read->data.read.rcvbuf,
                                     top_read->data.read.received,
                                     state->priv);
                if (!NT_STATUS_IS_OK(status)) {
                        async_req_error(state->req, status);
                        return;
                }
                state->pushed += top_read->data.read.received;

                TALLOC_FREE(state->reqs[state->top_req]);

                if (state->requested < state->size) {
                        struct async_req *new_req;
                        SMB_OFF_T size_left;
                        size_t request_thistime;

                        size_left = state->size - state->requested;
                        request_thistime = MIN(size_left, state->chunk_size);

                        DEBUG(10, ("cli_pull_read_done: Requesting %d bytes "
                                   "at %d, position %d\n",
                                   (int)request_thistime,
                                   (int)(state->start_offset
                                         + state->requested),
                                   state->top_req));

                        new_req = cli_read_andx_send(
                                state->reqs, state->cli, state->fnum,
                                state->start_offset + state->requested,
                                request_thistime);

                        if (async_req_nomem(new_req, state->req)) {
                                return;
                        }

                        new_req->async.fn = cli_pull_read_done;
                        new_req->async.priv = pull_req;

                        state->reqs[state->top_req] = new_req;
                        state->requested += request_thistime;
                }

                state->top_req = (state->top_req+1) % state->num_reqs;
        }

        async_req_done(pull_req);
}

NTSTATUS cli_pull_recv(struct async_req *req, SMB_OFF_T *received)
{
        struct cli_pull_state *state = talloc_get_type_abort(
                req->private_data, struct cli_pull_state);

        SMB_ASSERT(req->state >= ASYNC_REQ_DONE);
        if (req->state == ASYNC_REQ_ERROR) {
                return req->status;
        }
        *received = state->pushed;
        return NT_STATUS_OK;
}

NTSTATUS cli_pull(struct cli_state *cli, uint16_t fnum,
                  off_t start_offset, SMB_OFF_T size, size_t window_size,
                  NTSTATUS (*sink)(char *buf, size_t n, void *priv),
                  void *priv, SMB_OFF_T *received)
{
        TALLOC_CTX *frame = talloc_stackframe();
        struct async_req *req;
        NTSTATUS result = NT_STATUS_NO_MEMORY;

        if (cli_tmp_event_ctx(frame, cli) == NULL) {
                goto nomem;
        }

        req = cli_pull_send(frame, cli, fnum, start_offset, size, window_size,
                            sink, priv);
        if (req == NULL) {
                goto nomem;
        }

        while (req->state < ASYNC_REQ_DONE) {
                event_loop_once(cli->event_ctx);
        }

        result = cli_pull_recv(req, received);
 nomem:
        TALLOC_FREE(frame);
        return result;
}

static NTSTATUS cli_read_sink(char *buf, size_t n, void *priv)
{
        char **pbuf = (char **)priv;
        memcpy(*pbuf, buf, n);
        *pbuf += n;
        return NT_STATUS_OK;
}

ssize_t cli_read(struct cli_state *cli, int fnum, char *buf,
                 off_t offset, size_t size)
{
        NTSTATUS status;
        SMB_OFF_T ret;

        status = cli_pull(cli, fnum, offset, size, size,
                          cli_read_sink, &buf, &ret);
        if (!NT_STATUS_IS_OK(status)) {
                cli_set_error(cli, status);
                return -1;
        }
        return ret;
}

/****************************************************************************
 Issue a single SMBwrite and don't wait for a reply.
****************************************************************************/

static bool cli_issue_write(struct cli_state *cli,
                                int fnum,
                                off_t offset,
                                uint16 mode,
                                const char *buf,
                                size_t size,
                                int i)
{
        char *p;
        bool large_writex = false;
        /* We can only do direct writes if not signing and not encrypting. */
        bool direct_writes = !client_is_signing_on(cli) && !cli_encryption_on(cli);

        if (!direct_writes && size + 1 > cli->bufsize) {
                cli->outbuf = (char *)SMB_REALLOC(cli->outbuf, size + 1024);
                if (!cli->outbuf) {
                        return False;
                }
                cli->inbuf = (char *)SMB_REALLOC(cli->inbuf, size + 1024);
                if (cli->inbuf == NULL) {
                        SAFE_FREE(cli->outbuf);
                        return False;
                }
                cli->bufsize = size + 1024;
        }

        memset(cli->outbuf,'\0',smb_size);
        memset(cli->inbuf,'\0',smb_size);

        if (cli->capabilities & CAP_LARGE_FILES) {
                large_writex = True;
        }

        if (large_writex) {
                cli_set_message(cli->outbuf,14,0,True);
        } else {
                cli_set_message(cli->outbuf,12,0,True);
        }

        SCVAL(cli->outbuf,smb_com,SMBwriteX);
        SSVAL(cli->outbuf,smb_tid,cli->cnum);
        cli_setup_packet(cli);

        SCVAL(cli->outbuf,smb_vwv0,0xFF);
        SSVAL(cli->outbuf,smb_vwv2,fnum);

        SIVAL(cli->outbuf,smb_vwv3,offset);
        SIVAL(cli->outbuf,smb_vwv5,0);
        SSVAL(cli->outbuf,smb_vwv7,mode);

        SSVAL(cli->outbuf,smb_vwv8,(mode & 0x0008) ? size : 0);
        /*
         * According to CIFS-TR-1p00, this following field should only
         * be set if CAP_LARGE_WRITEX is set. We should check this
         * locally. However, this check might already have been
         * done by our callers.
         */
        SSVAL(cli->outbuf,smb_vwv9,(size>>16));
        SSVAL(cli->outbuf,smb_vwv10,size);
        /* +1 is pad byte. */
        SSVAL(cli->outbuf,smb_vwv11,
              smb_buf(cli->outbuf) - smb_base(cli->outbuf) + 1);

        if (large_writex) {
                SIVAL(cli->outbuf,smb_vwv12,(((SMB_BIG_UINT)offset)>>32) & 0xffffffff);
        }

        p = smb_base(cli->outbuf) + SVAL(cli->outbuf,smb_vwv11) -1;
        *p++ = '\0'; /* pad byte. */
        if (!direct_writes) {
                memcpy(p, buf, size);
        }
        if (size > 0x1FFFF) {
                /* This is a POSIX 14 word large write. */
                set_message_bcc(cli->outbuf, 0); /* Set bcc to zero. */
                _smb_setlen_large(cli->outbuf,smb_size + 28 + 1 /* pad */ + size - 4);
        } else {
                cli_setup_bcc(cli, p+size);
        }

        SSVAL(cli->outbuf,smb_mid,cli->mid + i);

        show_msg(cli->outbuf);
        if (direct_writes) {
                /* For direct writes we now need to write the data
                 * directly out of buf. */
                return cli_send_smb_direct_writeX(cli, buf, size);
        } else {
                return cli_send_smb(cli);
        }
}

/****************************************************************************
  write to a file
  write_mode: 0x0001 disallow write cacheing
              0x0002 return bytes remaining
              0x0004 use raw named pipe protocol
              0x0008 start of message mode named pipe protocol
****************************************************************************/

ssize_t cli_write(struct cli_state *cli,
                 int fnum, uint16 write_mode,
                 const char *buf, off_t offset, size_t size)
{
        ssize_t bwritten = 0;
        unsigned int issued = 0;
        unsigned int received = 0;
        int mpx = 1;
        size_t writesize;
        int blocks;

        if(cli->max_mux > 1) {
                mpx = cli->max_mux-1;
        } else {
                mpx = 1;
        }

        /* Default (small) writesize. */
        writesize = (cli->max_xmit - (smb_size+32)) & ~1023;

        if (write_mode == 0 &&
                        !client_is_signing_on(cli) &&
                        !cli_encryption_on(cli) &&
                        (cli->posix_capabilities & CIFS_UNIX_LARGE_WRITE_CAP) &&
                        (cli->capabilities & CAP_LARGE_FILES)) {
                /* Only do massive writes if we can do them direct
                 * with no signing or encrypting - not on a pipe. */
                writesize = CLI_SAMBA_MAX_POSIX_LARGE_WRITEX_SIZE;
        } else if ((cli->capabilities & CAP_LARGE_WRITEX) &&
                        (strcmp(cli->dev, "LPT1:") != 0)) {

                /* Printer devices are restricted to max_xmit
                 * writesize in Vista and XPSP3. */

                if (cli->is_samba) {
                        writesize = CLI_SAMBA_MAX_LARGE_WRITEX_SIZE;
                } else if (!client_is_signing_on(cli)) {
                        /* Windows restricts signed writes to max_xmit.
                         * Found by Volker. */
                        writesize = CLI_WINDOWS_MAX_LARGE_WRITEX_SIZE;
                }
        }

        blocks = (size + (writesize-1)) / writesize;

        while (received < blocks) {

                while ((issued - received < mpx) && (issued < blocks)) {
                        ssize_t bsent = issued * writesize;
                        ssize_t size1 = MIN(writesize, size - bsent);

                        if (!cli_issue_write(cli, fnum, offset + bsent,
                                        write_mode,
                                        buf + bsent,
                                        size1, issued))
                                return -1;
                        issued++;
                }

                if (!cli_receive_smb(cli)) {
                        return bwritten;
                }

                received++;

                if (cli_is_error(cli))
                        break;

                bwritten += SVAL(cli->inbuf, smb_vwv2);
                if (writesize > 0xFFFF) {
                        bwritten += (((int)(SVAL(cli->inbuf, smb_vwv4)))<<16);
                }
        }

        while (received < issued && cli_receive_smb(cli)) {
                received++;
        }

        return bwritten;
}

/****************************************************************************
  write to a file using a SMBwrite and not bypassing 0 byte writes
****************************************************************************/

ssize_t cli_smbwrite(struct cli_state *cli,
                     int fnum, char *buf, off_t offset, size_t size1)
{
        char *p;
        ssize_t total = 0;

        do {
                size_t size = MIN(size1, cli->max_xmit - 48);

                memset(cli->outbuf,'\0',smb_size);
                memset(cli->inbuf,'\0',smb_size);

                cli_set_message(cli->outbuf,5, 0,True);

                SCVAL(cli->outbuf,smb_com,SMBwrite);
                SSVAL(cli->outbuf,smb_tid,cli->cnum);
                cli_setup_packet(cli);

                SSVAL(cli->outbuf,smb_vwv0,fnum);
                SSVAL(cli->outbuf,smb_vwv1,size);
                SIVAL(cli->outbuf,smb_vwv2,offset);
                SSVAL(cli->outbuf,smb_vwv4,0);

                p = smb_buf(cli->outbuf);
                *p++ = 1;
                SSVAL(p, 0, size); p += 2;
                memcpy(p, buf + total, size); p += size;

                cli_setup_bcc(cli, p);

                if (!cli_send_smb(cli))
                        return -1;

                if (!cli_receive_smb(cli))
                        return -1;

                if (cli_is_error(cli))
                        return -1;

                size = SVAL(cli->inbuf,smb_vwv0);
                if (size == 0)
                        break;

                size1 -= size;
                total += size;
                offset += size;

        } while (size1);

        return total;
}