qemu/migration/qemu-file.c
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   1/*
   2 * QEMU System Emulator
   3 *
   4 * Copyright (c) 2003-2008 Fabrice Bellard
   5 *
   6 * Permission is hereby granted, free of charge, to any person obtaining a copy
   7 * of this software and associated documentation files (the "Software"), to deal
   8 * in the Software without restriction, including without limitation the rights
   9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10 * copies of the Software, and to permit persons to whom the Software is
  11 * furnished to do so, subject to the following conditions:
  12 *
  13 * The above copyright notice and this permission notice shall be included in
  14 * all copies or substantial portions of the Software.
  15 *
  16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22 * THE SOFTWARE.
  23 */
  24#include "qemu/osdep.h"
  25#include <zlib.h>
  26#include "qemu-common.h"
  27#include "qemu/error-report.h"
  28#include "qemu/iov.h"
  29#include "migration.h"
  30#include "qemu-file.h"
  31#include "trace.h"
  32
  33#define IO_BUF_SIZE 32768
  34#define MAX_IOV_SIZE MIN(IOV_MAX, 64)
  35
  36struct QEMUFile {
  37    const QEMUFileOps *ops;
  38    const QEMUFileHooks *hooks;
  39    void *opaque;
  40
  41    int64_t bytes_xfer;
  42    int64_t xfer_limit;
  43
  44    int64_t pos; /* start of buffer when writing, end of buffer
  45                    when reading */
  46    int buf_index;
  47    int buf_size; /* 0 when writing */
  48    uint8_t buf[IO_BUF_SIZE];
  49
  50    DECLARE_BITMAP(may_free, MAX_IOV_SIZE);
  51    struct iovec iov[MAX_IOV_SIZE];
  52    unsigned int iovcnt;
  53
  54    int last_error;
  55};
  56
  57/*
  58 * Stop a file from being read/written - not all backing files can do this
  59 * typically only sockets can.
  60 */
  61int qemu_file_shutdown(QEMUFile *f)
  62{
  63    if (!f->ops->shut_down) {
  64        return -ENOSYS;
  65    }
  66    return f->ops->shut_down(f->opaque, true, true);
  67}
  68
  69/*
  70 * Result: QEMUFile* for a 'return path' for comms in the opposite direction
  71 *         NULL if not available
  72 */
  73QEMUFile *qemu_file_get_return_path(QEMUFile *f)
  74{
  75    if (!f->ops->get_return_path) {
  76        return NULL;
  77    }
  78    return f->ops->get_return_path(f->opaque);
  79}
  80
  81bool qemu_file_mode_is_not_valid(const char *mode)
  82{
  83    if (mode == NULL ||
  84        (mode[0] != 'r' && mode[0] != 'w') ||
  85        mode[1] != 'b' || mode[2] != 0) {
  86        fprintf(stderr, "qemu_fopen: Argument validity check failed\n");
  87        return true;
  88    }
  89
  90    return false;
  91}
  92
  93QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops)
  94{
  95    QEMUFile *f;
  96
  97    f = g_new0(QEMUFile, 1);
  98
  99    f->opaque = opaque;
 100    f->ops = ops;
 101    return f;
 102}
 103
 104
 105void qemu_file_set_hooks(QEMUFile *f, const QEMUFileHooks *hooks)
 106{
 107    f->hooks = hooks;
 108}
 109
 110/*
 111 * Get last error for stream f
 112 *
 113 * Return negative error value if there has been an error on previous
 114 * operations, return 0 if no error happened.
 115 *
 116 */
 117int qemu_file_get_error(QEMUFile *f)
 118{
 119    return f->last_error;
 120}
 121
 122void qemu_file_set_error(QEMUFile *f, int ret)
 123{
 124    if (f->last_error == 0) {
 125        f->last_error = ret;
 126    }
 127}
 128
 129bool qemu_file_is_writable(QEMUFile *f)
 130{
 131    return f->ops->writev_buffer;
 132}
 133
 134static void qemu_iovec_release_ram(QEMUFile *f)
 135{
 136    struct iovec iov;
 137    unsigned long idx;
 138
 139    /* Find and release all the contiguous memory ranges marked as may_free. */
 140    idx = find_next_bit(f->may_free, f->iovcnt, 0);
 141    if (idx >= f->iovcnt) {
 142        return;
 143    }
 144    iov = f->iov[idx];
 145
 146    /* The madvise() in the loop is called for iov within a continuous range and
 147     * then reinitialize the iov. And in the end, madvise() is called for the
 148     * last iov.
 149     */
 150    while ((idx = find_next_bit(f->may_free, f->iovcnt, idx + 1)) < f->iovcnt) {
 151        /* check for adjacent buffer and coalesce them */
 152        if (iov.iov_base + iov.iov_len == f->iov[idx].iov_base) {
 153            iov.iov_len += f->iov[idx].iov_len;
 154            continue;
 155        }
 156        if (qemu_madvise(iov.iov_base, iov.iov_len, QEMU_MADV_DONTNEED) < 0) {
 157            error_report("migrate: madvise DONTNEED failed %p %zd: %s",
 158                         iov.iov_base, iov.iov_len, strerror(errno));
 159        }
 160        iov = f->iov[idx];
 161    }
 162    if (qemu_madvise(iov.iov_base, iov.iov_len, QEMU_MADV_DONTNEED) < 0) {
 163            error_report("migrate: madvise DONTNEED failed %p %zd: %s",
 164                         iov.iov_base, iov.iov_len, strerror(errno));
 165    }
 166    memset(f->may_free, 0, sizeof(f->may_free));
 167}
 168
 169/**
 170 * Flushes QEMUFile buffer
 171 *
 172 * If there is writev_buffer QEMUFileOps it uses it otherwise uses
 173 * put_buffer ops. This will flush all pending data. If data was
 174 * only partially flushed, it will set an error state.
 175 */
 176void qemu_fflush(QEMUFile *f)
 177{
 178    ssize_t ret = 0;
 179    ssize_t expect = 0;
 180
 181    if (!qemu_file_is_writable(f)) {
 182        return;
 183    }
 184
 185    if (f->iovcnt > 0) {
 186        expect = iov_size(f->iov, f->iovcnt);
 187        ret = f->ops->writev_buffer(f->opaque, f->iov, f->iovcnt, f->pos);
 188
 189        qemu_iovec_release_ram(f);
 190    }
 191
 192    if (ret >= 0) {
 193        f->pos += ret;
 194    }
 195    /* We expect the QEMUFile write impl to send the full
 196     * data set we requested, so sanity check that.
 197     */
 198    if (ret != expect) {
 199        qemu_file_set_error(f, ret < 0 ? ret : -EIO);
 200    }
 201    f->buf_index = 0;
 202    f->iovcnt = 0;
 203}
 204
 205void ram_control_before_iterate(QEMUFile *f, uint64_t flags)
 206{
 207    int ret = 0;
 208
 209    if (f->hooks && f->hooks->before_ram_iterate) {
 210        ret = f->hooks->before_ram_iterate(f, f->opaque, flags, NULL);
 211        if (ret < 0) {
 212            qemu_file_set_error(f, ret);
 213        }
 214    }
 215}
 216
 217void ram_control_after_iterate(QEMUFile *f, uint64_t flags)
 218{
 219    int ret = 0;
 220
 221    if (f->hooks && f->hooks->after_ram_iterate) {
 222        ret = f->hooks->after_ram_iterate(f, f->opaque, flags, NULL);
 223        if (ret < 0) {
 224            qemu_file_set_error(f, ret);
 225        }
 226    }
 227}
 228
 229void ram_control_load_hook(QEMUFile *f, uint64_t flags, void *data)
 230{
 231    int ret = -EINVAL;
 232
 233    if (f->hooks && f->hooks->hook_ram_load) {
 234        ret = f->hooks->hook_ram_load(f, f->opaque, flags, data);
 235        if (ret < 0) {
 236            qemu_file_set_error(f, ret);
 237        }
 238    } else {
 239        /*
 240         * Hook is a hook specifically requested by the source sending a flag
 241         * that expects there to be a hook on the destination.
 242         */
 243        if (flags == RAM_CONTROL_HOOK) {
 244            qemu_file_set_error(f, ret);
 245        }
 246    }
 247}
 248
 249size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
 250                             ram_addr_t offset, size_t size,
 251                             uint64_t *bytes_sent)
 252{
 253    if (f->hooks && f->hooks->save_page) {
 254        int ret = f->hooks->save_page(f, f->opaque, block_offset,
 255                                      offset, size, bytes_sent);
 256
 257        if (ret != RAM_SAVE_CONTROL_DELAYED) {
 258            if (bytes_sent && *bytes_sent > 0) {
 259                qemu_update_position(f, *bytes_sent);
 260            } else if (ret < 0) {
 261                qemu_file_set_error(f, ret);
 262            }
 263        }
 264
 265        return ret;
 266    }
 267
 268    return RAM_SAVE_CONTROL_NOT_SUPP;
 269}
 270
 271/*
 272 * Attempt to fill the buffer from the underlying file
 273 * Returns the number of bytes read, or negative value for an error.
 274 *
 275 * Note that it can return a partially full buffer even in a not error/not EOF
 276 * case if the underlying file descriptor gives a short read, and that can
 277 * happen even on a blocking fd.
 278 */
 279static ssize_t qemu_fill_buffer(QEMUFile *f)
 280{
 281    int len;
 282    int pending;
 283
 284    assert(!qemu_file_is_writable(f));
 285
 286    pending = f->buf_size - f->buf_index;
 287    if (pending > 0) {
 288        memmove(f->buf, f->buf + f->buf_index, pending);
 289    }
 290    f->buf_index = 0;
 291    f->buf_size = pending;
 292
 293    len = f->ops->get_buffer(f->opaque, f->buf + pending, f->pos,
 294                        IO_BUF_SIZE - pending);
 295    if (len > 0) {
 296        f->buf_size += len;
 297        f->pos += len;
 298    } else if (len == 0) {
 299        qemu_file_set_error(f, -EIO);
 300    } else if (len != -EAGAIN) {
 301        qemu_file_set_error(f, len);
 302    }
 303
 304    return len;
 305}
 306
 307void qemu_update_position(QEMUFile *f, size_t size)
 308{
 309    f->pos += size;
 310}
 311
 312/** Closes the file
 313 *
 314 * Returns negative error value if any error happened on previous operations or
 315 * while closing the file. Returns 0 or positive number on success.
 316 *
 317 * The meaning of return value on success depends on the specific backend
 318 * being used.
 319 */
 320int qemu_fclose(QEMUFile *f)
 321{
 322    int ret;
 323    qemu_fflush(f);
 324    ret = qemu_file_get_error(f);
 325
 326    if (f->ops->close) {
 327        int ret2 = f->ops->close(f->opaque);
 328        if (ret >= 0) {
 329            ret = ret2;
 330        }
 331    }
 332    /* If any error was spotted before closing, we should report it
 333     * instead of the close() return value.
 334     */
 335    if (f->last_error) {
 336        ret = f->last_error;
 337    }
 338    g_free(f);
 339    trace_qemu_file_fclose();
 340    return ret;
 341}
 342
 343static void add_to_iovec(QEMUFile *f, const uint8_t *buf, size_t size,
 344                         bool may_free)
 345{
 346    /* check for adjacent buffer and coalesce them */
 347    if (f->iovcnt > 0 && buf == f->iov[f->iovcnt - 1].iov_base +
 348        f->iov[f->iovcnt - 1].iov_len &&
 349        may_free == test_bit(f->iovcnt - 1, f->may_free))
 350    {
 351        f->iov[f->iovcnt - 1].iov_len += size;
 352    } else {
 353        if (may_free) {
 354            set_bit(f->iovcnt, f->may_free);
 355        }
 356        f->iov[f->iovcnt].iov_base = (uint8_t *)buf;
 357        f->iov[f->iovcnt++].iov_len = size;
 358    }
 359
 360    if (f->iovcnt >= MAX_IOV_SIZE) {
 361        qemu_fflush(f);
 362    }
 363}
 364
 365void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, size_t size,
 366                           bool may_free)
 367{
 368    if (f->last_error) {
 369        return;
 370    }
 371
 372    f->bytes_xfer += size;
 373    add_to_iovec(f, buf, size, may_free);
 374}
 375
 376void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, size_t size)
 377{
 378    size_t l;
 379
 380    if (f->last_error) {
 381        return;
 382    }
 383
 384    while (size > 0) {
 385        l = IO_BUF_SIZE - f->buf_index;
 386        if (l > size) {
 387            l = size;
 388        }
 389        memcpy(f->buf + f->buf_index, buf, l);
 390        f->bytes_xfer += l;
 391        add_to_iovec(f, f->buf + f->buf_index, l, false);
 392        f->buf_index += l;
 393        if (f->buf_index == IO_BUF_SIZE) {
 394            qemu_fflush(f);
 395        }
 396        if (qemu_file_get_error(f)) {
 397            break;
 398        }
 399        buf += l;
 400        size -= l;
 401    }
 402}
 403
 404void qemu_put_byte(QEMUFile *f, int v)
 405{
 406    if (f->last_error) {
 407        return;
 408    }
 409
 410    f->buf[f->buf_index] = v;
 411    f->bytes_xfer++;
 412    add_to_iovec(f, f->buf + f->buf_index, 1, false);
 413    f->buf_index++;
 414    if (f->buf_index == IO_BUF_SIZE) {
 415        qemu_fflush(f);
 416    }
 417}
 418
 419void qemu_file_skip(QEMUFile *f, int size)
 420{
 421    if (f->buf_index + size <= f->buf_size) {
 422        f->buf_index += size;
 423    }
 424}
 425
 426/*
 427 * Read 'size' bytes from file (at 'offset') without moving the
 428 * pointer and set 'buf' to point to that data.
 429 *
 430 * It will return size bytes unless there was an error, in which case it will
 431 * return as many as it managed to read (assuming blocking fd's which
 432 * all current QEMUFile are)
 433 */
 434size_t qemu_peek_buffer(QEMUFile *f, uint8_t **buf, size_t size, size_t offset)
 435{
 436    ssize_t pending;
 437    size_t index;
 438
 439    assert(!qemu_file_is_writable(f));
 440    assert(offset < IO_BUF_SIZE);
 441    assert(size <= IO_BUF_SIZE - offset);
 442
 443    /* The 1st byte to read from */
 444    index = f->buf_index + offset;
 445    /* The number of available bytes starting at index */
 446    pending = f->buf_size - index;
 447
 448    /*
 449     * qemu_fill_buffer might return just a few bytes, even when there isn't
 450     * an error, so loop collecting them until we get enough.
 451     */
 452    while (pending < size) {
 453        int received = qemu_fill_buffer(f);
 454
 455        if (received <= 0) {
 456            break;
 457        }
 458
 459        index = f->buf_index + offset;
 460        pending = f->buf_size - index;
 461    }
 462
 463    if (pending <= 0) {
 464        return 0;
 465    }
 466    if (size > pending) {
 467        size = pending;
 468    }
 469
 470    *buf = f->buf + index;
 471    return size;
 472}
 473
 474/*
 475 * Read 'size' bytes of data from the file into buf.
 476 * 'size' can be larger than the internal buffer.
 477 *
 478 * It will return size bytes unless there was an error, in which case it will
 479 * return as many as it managed to read (assuming blocking fd's which
 480 * all current QEMUFile are)
 481 */
 482size_t qemu_get_buffer(QEMUFile *f, uint8_t *buf, size_t size)
 483{
 484    size_t pending = size;
 485    size_t done = 0;
 486
 487    while (pending > 0) {
 488        size_t res;
 489        uint8_t *src;
 490
 491        res = qemu_peek_buffer(f, &src, MIN(pending, IO_BUF_SIZE), 0);
 492        if (res == 0) {
 493            return done;
 494        }
 495        memcpy(buf, src, res);
 496        qemu_file_skip(f, res);
 497        buf += res;
 498        pending -= res;
 499        done += res;
 500    }
 501    return done;
 502}
 503
 504/*
 505 * Read 'size' bytes of data from the file.
 506 * 'size' can be larger than the internal buffer.
 507 *
 508 * The data:
 509 *   may be held on an internal buffer (in which case *buf is updated
 510 *     to point to it) that is valid until the next qemu_file operation.
 511 * OR
 512 *   will be copied to the *buf that was passed in.
 513 *
 514 * The code tries to avoid the copy if possible.
 515 *
 516 * It will return size bytes unless there was an error, in which case it will
 517 * return as many as it managed to read (assuming blocking fd's which
 518 * all current QEMUFile are)
 519 *
 520 * Note: Since **buf may get changed, the caller should take care to
 521 *       keep a pointer to the original buffer if it needs to deallocate it.
 522 */
 523size_t qemu_get_buffer_in_place(QEMUFile *f, uint8_t **buf, size_t size)
 524{
 525    if (size < IO_BUF_SIZE) {
 526        size_t res;
 527        uint8_t *src;
 528
 529        res = qemu_peek_buffer(f, &src, size, 0);
 530
 531        if (res == size) {
 532            qemu_file_skip(f, res);
 533            *buf = src;
 534            return res;
 535        }
 536    }
 537
 538    return qemu_get_buffer(f, *buf, size);
 539}
 540
 541/*
 542 * Peeks a single byte from the buffer; this isn't guaranteed to work if
 543 * offset leaves a gap after the previous read/peeked data.
 544 */
 545int qemu_peek_byte(QEMUFile *f, int offset)
 546{
 547    int index = f->buf_index + offset;
 548
 549    assert(!qemu_file_is_writable(f));
 550    assert(offset < IO_BUF_SIZE);
 551
 552    if (index >= f->buf_size) {
 553        qemu_fill_buffer(f);
 554        index = f->buf_index + offset;
 555        if (index >= f->buf_size) {
 556            return 0;
 557        }
 558    }
 559    return f->buf[index];
 560}
 561
 562int qemu_get_byte(QEMUFile *f)
 563{
 564    int result;
 565
 566    result = qemu_peek_byte(f, 0);
 567    qemu_file_skip(f, 1);
 568    return result;
 569}
 570
 571int64_t qemu_ftell_fast(QEMUFile *f)
 572{
 573    int64_t ret = f->pos;
 574    int i;
 575
 576    for (i = 0; i < f->iovcnt; i++) {
 577        ret += f->iov[i].iov_len;
 578    }
 579
 580    return ret;
 581}
 582
 583int64_t qemu_ftell(QEMUFile *f)
 584{
 585    qemu_fflush(f);
 586    return f->pos;
 587}
 588
 589int qemu_file_rate_limit(QEMUFile *f)
 590{
 591    if (qemu_file_get_error(f)) {
 592        return 1;
 593    }
 594    if (f->xfer_limit > 0 && f->bytes_xfer > f->xfer_limit) {
 595        return 1;
 596    }
 597    return 0;
 598}
 599
 600int64_t qemu_file_get_rate_limit(QEMUFile *f)
 601{
 602    return f->xfer_limit;
 603}
 604
 605void qemu_file_set_rate_limit(QEMUFile *f, int64_t limit)
 606{
 607    f->xfer_limit = limit;
 608}
 609
 610void qemu_file_reset_rate_limit(QEMUFile *f)
 611{
 612    f->bytes_xfer = 0;
 613}
 614
 615void qemu_put_be16(QEMUFile *f, unsigned int v)
 616{
 617    qemu_put_byte(f, v >> 8);
 618    qemu_put_byte(f, v);
 619}
 620
 621void qemu_put_be32(QEMUFile *f, unsigned int v)
 622{
 623    qemu_put_byte(f, v >> 24);
 624    qemu_put_byte(f, v >> 16);
 625    qemu_put_byte(f, v >> 8);
 626    qemu_put_byte(f, v);
 627}
 628
 629void qemu_put_be64(QEMUFile *f, uint64_t v)
 630{
 631    qemu_put_be32(f, v >> 32);
 632    qemu_put_be32(f, v);
 633}
 634
 635unsigned int qemu_get_be16(QEMUFile *f)
 636{
 637    unsigned int v;
 638    v = qemu_get_byte(f) << 8;
 639    v |= qemu_get_byte(f);
 640    return v;
 641}
 642
 643unsigned int qemu_get_be32(QEMUFile *f)
 644{
 645    unsigned int v;
 646    v = (unsigned int)qemu_get_byte(f) << 24;
 647    v |= qemu_get_byte(f) << 16;
 648    v |= qemu_get_byte(f) << 8;
 649    v |= qemu_get_byte(f);
 650    return v;
 651}
 652
 653uint64_t qemu_get_be64(QEMUFile *f)
 654{
 655    uint64_t v;
 656    v = (uint64_t)qemu_get_be32(f) << 32;
 657    v |= qemu_get_be32(f);
 658    return v;
 659}
 660
 661/* Compress size bytes of data start at p with specific compression
 662 * level and store the compressed data to the buffer of f.
 663 *
 664 * When f is not writable, return -1 if f has no space to save the
 665 * compressed data.
 666 * When f is wirtable and it has no space to save the compressed data,
 667 * do fflush first, if f still has no space to save the compressed
 668 * data, return -1.
 669 */
 670
 671ssize_t qemu_put_compression_data(QEMUFile *f, const uint8_t *p, size_t size,
 672                                  int level)
 673{
 674    ssize_t blen = IO_BUF_SIZE - f->buf_index - sizeof(int32_t);
 675
 676    if (blen < compressBound(size)) {
 677        if (!qemu_file_is_writable(f)) {
 678            return -1;
 679        }
 680        qemu_fflush(f);
 681        blen = IO_BUF_SIZE - sizeof(int32_t);
 682        if (blen < compressBound(size)) {
 683            return -1;
 684        }
 685    }
 686    if (compress2(f->buf + f->buf_index + sizeof(int32_t), (uLongf *)&blen,
 687                  (Bytef *)p, size, level) != Z_OK) {
 688        error_report("Compress Failed!");
 689        return 0;
 690    }
 691    qemu_put_be32(f, blen);
 692    if (f->ops->writev_buffer) {
 693        add_to_iovec(f, f->buf + f->buf_index, blen, false);
 694    }
 695    f->buf_index += blen;
 696    if (f->buf_index == IO_BUF_SIZE) {
 697        qemu_fflush(f);
 698    }
 699    return blen + sizeof(int32_t);
 700}
 701
 702/* Put the data in the buffer of f_src to the buffer of f_des, and
 703 * then reset the buf_index of f_src to 0.
 704 */
 705
 706int qemu_put_qemu_file(QEMUFile *f_des, QEMUFile *f_src)
 707{
 708    int len = 0;
 709
 710    if (f_src->buf_index > 0) {
 711        len = f_src->buf_index;
 712        qemu_put_buffer(f_des, f_src->buf, f_src->buf_index);
 713        f_src->buf_index = 0;
 714        f_src->iovcnt = 0;
 715    }
 716    return len;
 717}
 718
 719/*
 720 * Get a string whose length is determined by a single preceding byte
 721 * A preallocated 256 byte buffer must be passed in.
 722 * Returns: len on success and a 0 terminated string in the buffer
 723 *          else 0
 724 *          (Note a 0 length string will return 0 either way)
 725 */
 726size_t qemu_get_counted_string(QEMUFile *f, char buf[256])
 727{
 728    size_t len = qemu_get_byte(f);
 729    size_t res = qemu_get_buffer(f, (uint8_t *)buf, len);
 730
 731    buf[res] = 0;
 732
 733    return res == len ? res : 0;
 734}
 735
 736/*
 737 * Set the blocking state of the QEMUFile.
 738 * Note: On some transports the OS only keeps a single blocking state for
 739 *       both directions, and thus changing the blocking on the main
 740 *       QEMUFile can also affect the return path.
 741 */
 742void qemu_file_set_blocking(QEMUFile *f, bool block)
 743{
 744    if (f->ops->set_blocking) {
 745        f->ops->set_blocking(f->opaque, block);
 746    }
 747}
 748