io.c

   1 /*
   2  * Socket and pipe I/O utilities used in rsync.
   3  *
   4  * Copyright (C) 1996-2001 Andrew Tridgell
   5  * Copyright (C) 1996 Paul Mackerras
   6  * Copyright (C) 2001, 2002 Martin Pool <mbp@samba.org>
   7  * Copyright (C) 2003, 2004, 2005, 2006 Wayne Davison
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write to the Free Software Foundation, Inc.,
  21  * 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
  22  */
  23
  24 /* Rsync provides its own multiplexing system, which is used to send
  25  * stderr and stdout over a single socket.
  26  *
  27  * For historical reasons this is off during the start of the
  28  * connection, but it's switched on quite early using
  29  * io_start_multiplex_out() and io_start_multiplex_in(). */
  30
  31 #include "rsync.h"
  32
  33 /** If no timeout is specified then use a 60 second select timeout */
  34 #define SELECT_TIMEOUT 60
  35
  36 extern int bwlimit;
  37 extern size_t bwlimit_writemax;
  38 extern int io_timeout;
  39 extern int allowed_lull;
  40 extern int am_server;
  41 extern int am_daemon;
  42 extern int am_sender;
  43 extern int am_generator;
  44 extern int eol_nulls;
  45 extern int read_batch;
  46 extern int csum_length;
  47 extern int checksum_seed;
  48 extern int protocol_version;
  49 extern int remove_sent_files;
  50 extern int preserve_hard_links;
  51 extern char *filesfrom_host;
  52 extern struct stats stats;
  53 extern struct file_list *the_file_list;
  54
  55 const char phase_unknown[] = "unknown";
  56 int ignore_timeout = 0;
  57 int batch_fd = -1;
  58 int batch_gen_fd = -1;
  59
  60 /* Ignore an EOF error if non-zero. See whine_about_eof(). */
  61 int kluge_around_eof = 0;
  62
  63 int msg_fd_in = -1;
  64 int msg_fd_out = -1;
  65 int sock_f_in = -1;
  66 int sock_f_out = -1;
  67
  68 static int io_multiplexing_out;
  69 static int io_multiplexing_in;
  70 static time_t last_io_in;
  71 static time_t last_io_out;
  72 static int no_flush;
  73
  74 static int write_batch_monitor_in = -1;
  75 static int write_batch_monitor_out = -1;
  76
  77 static int io_filesfrom_f_in = -1;
  78 static int io_filesfrom_f_out = -1;
  79 static char io_filesfrom_buf[2048];
  80 static char *io_filesfrom_bp;
  81 static char io_filesfrom_lastchar;
  82 static int io_filesfrom_buflen;
  83 static int defer_forwarding_messages = 0;
  84 static int select_timeout = SELECT_TIMEOUT;
  85 static int active_filecnt = 0;
  86 static OFF_T active_bytecnt = 0;
  87
  88 static void read_loop(int fd, char *buf, size_t len);
  89
  90 struct flist_ndx_item {
  91         struct flist_ndx_item *next;
  92         int ndx;
  93 };
  94
  95 struct flist_ndx_list {
  96         struct flist_ndx_item *head, *tail;
  97 };
  98
  99 static struct flist_ndx_list redo_list, hlink_list;
 100
 101 struct msg_list_item {
 102         struct msg_list_item *next;
 103         int len;
 104         char buf[1];
 105 };
 106
 107 struct msg_list {
 108         struct msg_list_item *head, *tail;
 109 };
 110
 111 static struct msg_list msg2genr, msg2sndr;
 112
 113 static void flist_ndx_push(struct flist_ndx_list *lp, int ndx)
 114 {
 115         struct flist_ndx_item *item;
 116
 117         if (!(item = new(struct flist_ndx_item)))
 118                 out_of_memory("flist_ndx_push");
 119         item->next = NULL;
 120         item->ndx = ndx;
 121         if (lp->tail)
 122                 lp->tail->next = item;
 123         else
 124                 lp->head = item;
 125         lp->tail = item;
 126 }
 127
 128 static int flist_ndx_pop(struct flist_ndx_list *lp)
 129 {
 130         struct flist_ndx_item *next;
 131         int ndx;
 132
 133         if (!lp->head)
 134                 return -1;
 135
 136         ndx = lp->head->ndx;
 137         next = lp->head->next;
 138         free(lp->head);
 139         lp->head = next;
 140         if (!next)
 141                 lp->tail = NULL;
 142
 143         return ndx;
 144 }
 145
 146 static void check_timeout(void)
 147 {
 148         time_t t;
 149
 150         if (!io_timeout || ignore_timeout)
 151                 return;
 152
 153         if (!last_io_in) {
 154                 last_io_in = time(NULL);
 155                 return;
 156         }
 157
 158         t = time(NULL);
 159
 160         if (t - last_io_in >= io_timeout) {
 161                 if (!am_server && !am_daemon) {
 162                         rprintf(FERROR, "io timeout after %d seconds -- exiting\n",
 163                                 (int)(t-last_io_in));
 164                 }
 165                 exit_cleanup(RERR_TIMEOUT);
 166         }
 167 }
 168
 169 /* Note the fds used for the main socket (which might really be a pipe
 170  * for a local transfer, but we can ignore that). */
 171 void io_set_sock_fds(int f_in, int f_out)
 172 {
 173         sock_f_in = f_in;
 174         sock_f_out = f_out;
 175 }
 176
 177 void set_io_timeout(int secs)
 178 {
 179         io_timeout = secs;
 180
 181         if (!io_timeout || io_timeout > SELECT_TIMEOUT)
 182                 select_timeout = SELECT_TIMEOUT;
 183         else
 184                 select_timeout = io_timeout;
 185
 186         allowed_lull = read_batch ? 0 : (io_timeout + 1) / 2;
 187 }
 188
 189 /* Setup the fd used to receive MSG_* messages.  Only needed during the
 190  * early stages of being a local sender (up through the sending of the
 191  * file list) or when we're the generator (to fetch the messages from
 192  * the receiver). */
 193 void set_msg_fd_in(int fd)
 194 {
 195         msg_fd_in = fd;
 196 }
 197
 198 /* Setup the fd used to send our MSG_* messages.  Only needed when
 199  * we're the receiver (to send our messages to the generator). */
 200 void set_msg_fd_out(int fd)
 201 {
 202         msg_fd_out = fd;
 203         set_nonblocking(msg_fd_out);
 204 }
 205
 206 /* Add a message to the pending MSG_* list. */
 207 static void msg_list_add(struct msg_list *lst, int code, char *buf, int len)
 208 {
 209         struct msg_list_item *m;
 210         int sz = len + 4 + sizeof m[0] - 1;
 211
 212         if (!(m = (struct msg_list_item *)new_array(char, sz)))
 213                 out_of_memory("msg_list_add");
 214         m->next = NULL;
 215         m->len = len + 4;
 216         SIVAL(m->buf, 0, ((code+MPLEX_BASE)<<24) | len);
 217         memcpy(m->buf + 4, buf, len);
 218         if (lst->tail)
 219                 lst->tail->next = m;
 220         else
 221                 lst->head = m;
 222         lst->tail = m;
 223 }
 224
 225 /* Read a message from the MSG_* fd and handle it.  This is called either
 226  * during the early stages of being a local sender (up through the sending
 227  * of the file list) or when we're the generator (to fetch the messages
 228  * from the receiver). */
 229 static void read_msg_fd(void)
 230 {
 231         char buf[2048];
 232         size_t n;
 233         int fd = msg_fd_in;
 234         int tag, len;
 235
 236         /* Temporarily disable msg_fd_in.  This is needed to avoid looping back
 237          * to this routine from writefd_unbuffered(). */
 238         msg_fd_in = -1;
 239
 240         read_loop(fd, buf, 4);
 241         tag = IVAL(buf, 0);
 242
 243         len = tag & 0xFFFFFF;
 244         tag = (tag >> 24) - MPLEX_BASE;
 245
 246         switch (tag) {
 247         case MSG_DONE:
 248                 if (len != 0 || !am_generator) {
 249                         rprintf(FERROR, "invalid message %d:%d\n", tag, len);
 250                         exit_cleanup(RERR_STREAMIO);
 251                 }
 252                 flist_ndx_push(&redo_list, -1);
 253                 break;
 254         case MSG_REDO:
 255                 if (len != 4 || !am_generator) {
 256                         rprintf(FERROR, "invalid message %d:%d\n", tag, len);
 257                         exit_cleanup(RERR_STREAMIO);
 258                 }
 259                 read_loop(fd, buf, 4);
 260                 if (remove_sent_files)
 261                         decrement_active_files(IVAL(buf,0));
 262                 flist_ndx_push(&redo_list, IVAL(buf,0));
 263                 break;
 264         case MSG_DELETED:
 265                 if (len >= (int)sizeof buf || !am_generator) {
 266                         rprintf(FERROR, "invalid message %d:%d\n", tag, len);
 267                         exit_cleanup(RERR_STREAMIO);
 268                 }
 269                 read_loop(fd, buf, len);
 270                 send_msg(MSG_DELETED, buf, len);
 271                 break;
 272         case MSG_SUCCESS:
 273                 if (len != 4 || !am_generator) {
 274                         rprintf(FERROR, "invalid message %d:%d\n", tag, len);
 275                         exit_cleanup(RERR_STREAMIO);
 276                 }
 277                 read_loop(fd, buf, len);
 278                 if (remove_sent_files) {
 279                         decrement_active_files(IVAL(buf,0));
 280                         send_msg(MSG_SUCCESS, buf, len);
 281                 }
 282                 if (preserve_hard_links)
 283                         flist_ndx_push(&hlink_list, IVAL(buf,0));
 284                 break;
 285         case MSG_SOCKERR:
 286                 if (!am_generator) {
 287                         rprintf(FERROR, "invalid message %d:%d\n", tag, len);
 288                         exit_cleanup(RERR_STREAMIO);
 289                 }
 290                 close_multiplexing_out();
 291                 /* FALL THROUGH */
 292         case MSG_INFO:
 293         case MSG_ERROR:
 294         case MSG_LOG:
 295                 while (len) {
 296                         n = len;
 297                         if (n >= sizeof buf)
 298                                 n = sizeof buf - 1;
 299                         read_loop(fd, buf, n);
 300                         rwrite(tag, buf, n);
 301                         len -= n;
 302                 }
 303                 break;
 304         default:
 305                 rprintf(FERROR, "unknown message %d:%d [%s]\n",
 306                         tag, len, who_am_i());
 307                 exit_cleanup(RERR_STREAMIO);
 308         }
 309
 310         msg_fd_in = fd;
 311 }
 312
 313 /* This is used by the generator to limit how many file transfers can
 314  * be active at once when --remove-sent-files is specified.  Without
 315  * this, sender-side deletions were mostly happening at the end. */
 316 void increment_active_files(int ndx, int itemizing, enum logcode code)
 317 {
 318         /* TODO: tune these limits? */
 319         while (active_filecnt >= (active_bytecnt >= 128*1024 ? 10 : 50)) {
 320                 if (hlink_list.head)
 321                         check_for_finished_hlinks(itemizing, code);
 322                 read_msg_fd();
 323         }
 324
 325         active_filecnt++;
 326         active_bytecnt += the_file_list->files[ndx]->length;
 327 }
 328
 329 void decrement_active_files(int ndx)
 330 {
 331         active_filecnt--;
 332         active_bytecnt -= the_file_list->files[ndx]->length;
 333 }
 334
 335 /* Try to push messages off the list onto the wire.  If we leave with more
 336  * to do, return 0.  On error, return -1.  If everything flushed, return 1.
 337  * This is only active in the receiver. */
 338 static int msg2genr_flush(int flush_it_all)
 339 {
 340         static int written = 0;
 341         struct timeval tv;
 342         fd_set fds;
 343
 344         if (msg_fd_out < 0)
 345                 return -1;
 346
 347         while (msg2genr.head) {
 348                 struct msg_list_item *m = msg2genr.head;
 349                 int n = write(msg_fd_out, m->buf + written, m->len - written);
 350                 if (n < 0) {
 351                         if (errno == EINTR)
 352                                 continue;
 353                         if (errno != EWOULDBLOCK && errno != EAGAIN)
 354                                 return -1;
 355                         if (!flush_it_all)
 356                                 return 0;
 357                         FD_ZERO(&fds);
 358                         FD_SET(msg_fd_out, &fds);
 359                         tv.tv_sec = select_timeout;
 360                         tv.tv_usec = 0;
 361                         if (!select(msg_fd_out+1, NULL, &fds, NULL, &tv))
 362                                 check_timeout();
 363                 } else if ((written += n) == m->len) {
 364                         msg2genr.head = m->next;
 365                         if (!msg2genr.head)
 366                                 msg2genr.tail = NULL;
 367                         free(m);
 368                         written = 0;
 369                 }
 370         }
 371         return 1;
 372 }
 373
 374 int send_msg(enum msgcode code, char *buf, int len)
 375 {
 376         if (msg_fd_out < 0) {
 377                 if (!defer_forwarding_messages)
 378                         return io_multiplex_write(code, buf, len);
 379                 if (!io_multiplexing_out)
 380                         return 0;
 381                 msg_list_add(&msg2sndr, code, buf, len);
 382                 return 1;
 383         }
 384         msg_list_add(&msg2genr, code, buf, len);
 385         msg2genr_flush(NORMAL_FLUSH);
 386         return 1;
 387 }
 388
 389 int get_redo_num(int itemizing, enum logcode code)
 390 {
 391         while (1) {
 392                 if (hlink_list.head)
 393                         check_for_finished_hlinks(itemizing, code);
 394                 if (redo_list.head)
 395                         break;
 396                 read_msg_fd();
 397         }
 398
 399         return flist_ndx_pop(&redo_list);
 400 }
 401
 402 int get_hlink_num(void)
 403 {
 404         return flist_ndx_pop(&hlink_list);
 405 }
 406
 407 /**
 408  * When we're the receiver and we have a local --files-from list of names
 409  * that needs to be sent over the socket to the sender, we have to do two
 410  * things at the same time: send the sender a list of what files we're
 411  * processing and read the incoming file+info list from the sender.  We do
 412  * this by augmenting the read_timeout() function to copy this data.  It
 413  * uses the io_filesfrom_buf to read a block of data from f_in (when it is
 414  * ready, since it might be a pipe) and then blast it out f_out (when it
 415  * is ready to receive more data).
 416  */
 417 void io_set_filesfrom_fds(int f_in, int f_out)
 418 {
 419         io_filesfrom_f_in = f_in;
 420         io_filesfrom_f_out = f_out;
 421         io_filesfrom_bp = io_filesfrom_buf;
 422         io_filesfrom_lastchar = '\0';
 423         io_filesfrom_buflen = 0;
 424 }
 425
 426 /* It's almost always an error to get an EOF when we're trying to read from the
 427  * network, because the protocol is (for the most part) self-terminating.
 428  *
 429  * There is one case for the receiver when it is at the end of the transfer
 430  * (hanging around reading any keep-alive packets that might come its way): if
 431  * the sender dies before the generator's kill-signal comes through, we can end
 432  * up here needing to loop until the kill-signal arrives.  In this situation,
 433  * kluge_around_eof will be < 0.
 434  *
 435  * There is another case for older protocol versions (< 24) where the module
 436  * listing was not terminated, so we must ignore an EOF error in that case and
 437  * exit.  In this situation, kluge_around_eof will be > 0. */
 438 static void whine_about_eof(int fd)
 439 {
 440         if (kluge_around_eof && fd == sock_f_in) {
 441                 int i;
 442                 if (kluge_around_eof > 0)
 443                         exit_cleanup(0);
 444                 /* If we're still here after 10 seconds, exit with an error. */
 445                 for (i = 10*1000/20; i--; )
 446                         msleep(20);
 447         }
 448
 449         rprintf(FERROR, RSYNC_NAME ": connection unexpectedly closed "
 450                 "(%.0f bytes received so far) [%s]\n",
 451                 (double)stats.total_read, who_am_i());
 452
 453         exit_cleanup(RERR_STREAMIO);
 454 }
 455
 456 /**
 457  * Read from a socket with I/O timeout. return the number of bytes
 458  * read. If no bytes can be read then exit, never return a number <= 0.
 459  *
 460  * TODO: If the remote shell connection fails, then current versions
 461  * actually report an "unexpected EOF" error here.  Since it's a
 462  * fairly common mistake to try to use rsh when ssh is required, we
 463  * should trap that: if we fail to read any data at all, we should
 464  * give a better explanation.  We can tell whether the connection has
 465  * started by looking e.g. at whether the remote version is known yet.
 466  */
 467 static int read_timeout(int fd, char *buf, size_t len)
 468 {
 469         int n, cnt = 0;
 470
 471         io_flush(NORMAL_FLUSH);
 472
 473         while (cnt == 0) {
 474                 /* until we manage to read *something* */
 475                 fd_set r_fds, w_fds;
 476                 struct timeval tv;
 477                 int maxfd = fd;
 478                 int count;
 479
 480                 FD_ZERO(&r_fds);
 481                 FD_ZERO(&w_fds);
 482                 FD_SET(fd, &r_fds);
 483                 if (msg2genr.head) {
 484                         FD_SET(msg_fd_out, &w_fds);
 485                         if (msg_fd_out > maxfd)
 486                                 maxfd = msg_fd_out;
 487                 }
 488                 if (io_filesfrom_f_out >= 0) {
 489                         int new_fd;
 490                         if (io_filesfrom_buflen == 0) {
 491                                 if (io_filesfrom_f_in >= 0) {
 492                                         FD_SET(io_filesfrom_f_in, &r_fds);
 493                                         new_fd = io_filesfrom_f_in;
 494                                 } else {
 495                                         io_filesfrom_f_out = -1;
 496                                         new_fd = -1;
 497                                 }
 498                         } else {
 499                                 FD_SET(io_filesfrom_f_out, &w_fds);
 500                                 new_fd = io_filesfrom_f_out;
 501                         }
 502                         if (new_fd > maxfd)
 503                                 maxfd = new_fd;
 504                 }
 505
 506                 tv.tv_sec = select_timeout;
 507                 tv.tv_usec = 0;
 508
 509                 errno = 0;
 510
 511                 count = select(maxfd + 1, &r_fds, &w_fds, NULL, &tv);
 512
 513                 if (count <= 0) {
 514                         if (errno == EBADF)
 515                                 exit_cleanup(RERR_SOCKETIO);
 516                         check_timeout();
 517                         continue;
 518                 }
 519
 520                 if (msg2genr.head && FD_ISSET(msg_fd_out, &w_fds))
 521                         msg2genr_flush(NORMAL_FLUSH);
 522
 523                 if (io_filesfrom_f_out >= 0) {
 524                         if (io_filesfrom_buflen) {
 525                                 if (FD_ISSET(io_filesfrom_f_out, &w_fds)) {
 526                                         int l = write(io_filesfrom_f_out,
 527                                                       io_filesfrom_bp,
 528                                                       io_filesfrom_buflen);
 529                                         if (l > 0) {
 530                                                 if (!(io_filesfrom_buflen -= l))
 531                                                         io_filesfrom_bp = io_filesfrom_buf;
 532                                                 else
 533                                                         io_filesfrom_bp += l;
 534                                         } else {
 535                                                 /* XXX should we complain? */
 536                                                 io_filesfrom_f_out = -1;
 537                                         }
 538                                 }
 539                         } else if (io_filesfrom_f_in >= 0) {
 540                                 if (FD_ISSET(io_filesfrom_f_in, &r_fds)) {
 541                                         int l = read(io_filesfrom_f_in,
 542                                                      io_filesfrom_buf,
 543                                                      sizeof io_filesfrom_buf);
 544                                         if (l <= 0) {
 545                                                 /* Send end-of-file marker */
 546                                                 io_filesfrom_buf[0] = '\0';
 547                                                 io_filesfrom_buf[1] = '\0';
 548                                                 io_filesfrom_buflen = io_filesfrom_lastchar? 2 : 1;
 549                                                 io_filesfrom_f_in = -1;
 550                                         } else {
 551                                                 if (!eol_nulls) {
 552                                                         char *s = io_filesfrom_buf + l;
 553                                                         /* Transform CR and/or LF into '\0' */
 554                                                         while (s-- > io_filesfrom_buf) {
 555                                                                 if (*s == '\n' || *s == '\r')
 556                                                                         *s = '\0';
 557                                                         }
 558                                                 }
 559                                                 if (!io_filesfrom_lastchar) {
 560                                                         /* Last buf ended with a '\0', so don't
 561                                                          * let this buf start with one. */
 562                                                         while (l && !*io_filesfrom_bp)
 563                                                                 io_filesfrom_bp++, l--;
 564                                                 }
 565                                                 if (!l)
 566                                                         io_filesfrom_bp = io_filesfrom_buf;
 567                                                 else {
 568                                                         char *f = io_filesfrom_bp;
 569                                                         char *t = f;
 570                                                         char *eob = f + l;
 571                                                         /* Eliminate any multi-'\0' runs. */
 572                                                         while (f != eob) {
 573                                                                 if (!(*t++ = *f++)) {
 574                                                                         while (f != eob && !*f)
 575                                                                                 f++, l--;
 576                                                                 }
 577                                                         }
 578                                                         io_filesfrom_lastchar = f[-1];
 579                                                 }
 580                                                 io_filesfrom_buflen = l;
 581                                         }
 582                                 }
 583                         }
 584                 }
 585
 586                 if (!FD_ISSET(fd, &r_fds))
 587                         continue;
 588
 589                 n = read(fd, buf, len);
 590
 591                 if (n <= 0) {
 592                         if (n == 0)
 593                                 whine_about_eof(fd); /* Doesn't return. */
 594                         if (errno == EINTR || errno == EWOULDBLOCK
 595                             || errno == EAGAIN)
 596                                 continue;
 597
 598                         /* Don't write errors on a dead socket. */
 599                         if (fd == sock_f_in) {
 600                                 close_multiplexing_out();
 601                                 rsyserr(FSOCKERR, errno, "read error");
 602                         } else
 603                                 rsyserr(FERROR, errno, "read error");
 604                         exit_cleanup(RERR_STREAMIO);
 605                 }
 606
 607                 buf += n;
 608                 len -= n;
 609                 cnt += n;
 610
 611                 if (fd == sock_f_in && io_timeout)
 612                         last_io_in = time(NULL);
 613         }
 614
 615         return cnt;
 616 }
 617
 618 /**
 619  * Read a line into the "fname" buffer (which must be at least MAXPATHLEN
 620  * characters long).
 621  */
 622 int read_filesfrom_line(int fd, char *fname)
 623 {
 624         char ch, *s, *eob = fname + MAXPATHLEN - 1;
 625         int cnt;
 626         int reading_remotely = filesfrom_host != NULL;
 627         int nulls = eol_nulls || reading_remotely;
 628
 629   start:
 630         s = fname;
 631         while (1) {
 632                 cnt = read(fd, &ch, 1);
 633                 if (cnt < 0 && (errno == EWOULDBLOCK
 634                   || errno == EINTR || errno == EAGAIN)) {
 635                         struct timeval tv;
 636                         fd_set fds;
 637                         FD_ZERO(&fds);
 638                         FD_SET(fd, &fds);
 639                         tv.tv_sec = select_timeout;
 640                         tv.tv_usec = 0;
 641                         if (!select(fd+1, &fds, NULL, NULL, &tv))
 642                                 check_timeout();
 643                         continue;
 644                 }
 645                 if (cnt != 1)
 646                         break;
 647                 if (nulls? !ch : (ch == '\r' || ch == '\n')) {
 648                         /* Skip empty lines if reading locally. */
 649                         if (!reading_remotely && s == fname)
 650                                 continue;
 651                         break;
 652                 }
 653                 if (s < eob)
 654                         *s++ = ch;
 655         }
 656         *s = '\0';
 657
 658         /* Dump comments. */
 659         if (*fname == '#' || *fname == ';')
 660                 goto start;
 661
 662         return s - fname;
 663 }
 664
 665 static char *iobuf_out;
 666 static int iobuf_out_cnt;
 667
 668 void io_start_buffering_out(void)
 669 {
 670         if (iobuf_out)
 671                 return;
 672         if (!(iobuf_out = new_array(char, IO_BUFFER_SIZE)))
 673                 out_of_memory("io_start_buffering_out");
 674         iobuf_out_cnt = 0;
 675 }
 676
 677 static char *iobuf_in;
 678 static size_t iobuf_in_siz;
 679
 680 void io_start_buffering_in(void)
 681 {
 682         if (iobuf_in)
 683                 return;
 684         iobuf_in_siz = 2 * IO_BUFFER_SIZE;
 685         if (!(iobuf_in = new_array(char, iobuf_in_siz)))
 686                 out_of_memory("io_start_buffering_in");
 687 }
 688
 689 void io_end_buffering(void)
 690 {
 691         io_flush(NORMAL_FLUSH);
 692         if (!io_multiplexing_out) {
 693                 free(iobuf_out);
 694                 iobuf_out = NULL;
 695         }
 696 }
 697
 698 void maybe_flush_socket(void)
 699 {
 700         if (iobuf_out && iobuf_out_cnt && time(NULL) - last_io_out >= 5)
 701                 io_flush(NORMAL_FLUSH);
 702 }
 703
 704 void maybe_send_keepalive(void)
 705 {
 706         if (time(NULL) - last_io_out >= allowed_lull) {
 707                 if (!iobuf_out || !iobuf_out_cnt) {
 708                         if (protocol_version < 29)
 709                                 return; /* there's nothing we can do */
 710                         write_int(sock_f_out, the_file_list->count);
 711                         write_shortint(sock_f_out, ITEM_IS_NEW);
 712                 }
 713                 if (iobuf_out)
 714                         io_flush(NORMAL_FLUSH);
 715         }
 716 }
 717
 718 /**
 719  * Continue trying to read len bytes - don't return until len has been
 720  * read.
 721  **/
 722 static void read_loop(int fd, char *buf, size_t len)
 723 {
 724         while (len) {
 725                 int n = read_timeout(fd, buf, len);
 726
 727                 buf += n;
 728                 len -= n;
 729         }
 730 }
 731
 732 /**
 733  * Read from the file descriptor handling multiplexing - return number
 734  * of bytes read.
 735  *
 736  * Never returns <= 0.
 737  */
 738 static int readfd_unbuffered(int fd, char *buf, size_t len)
 739 {
 740         static size_t remaining;
 741         static size_t iobuf_in_ndx;
 742         size_t msg_bytes;
 743         int tag, cnt = 0;
 744         char line[BIGPATHBUFLEN];
 745
 746         if (!iobuf_in || fd != sock_f_in)
 747                 return read_timeout(fd, buf, len);
 748
 749         if (!io_multiplexing_in && remaining == 0) {
 750                 remaining = read_timeout(fd, iobuf_in, iobuf_in_siz);
 751                 iobuf_in_ndx = 0;
 752         }
 753
 754         while (cnt == 0) {
 755                 if (remaining) {
 756                         len = MIN(len, remaining);
 757                         memcpy(buf, iobuf_in + iobuf_in_ndx, len);
 758                         iobuf_in_ndx += len;
 759                         remaining -= len;
 760                         cnt = len;
 761                         break;
 762                 }
 763
 764                 read_loop(fd, line, 4);
 765                 tag = IVAL(line, 0);
 766
 767                 msg_bytes = tag & 0xFFFFFF;
 768                 tag = (tag >> 24) - MPLEX_BASE;
 769
 770                 switch (tag) {
 771                 case MSG_DATA:
 772                         if (msg_bytes > iobuf_in_siz) {
 773                                 if (!(iobuf_in = realloc_array(iobuf_in, char,
 774                                                                msg_bytes)))
 775                                         out_of_memory("readfd_unbuffered");
 776                                 iobuf_in_siz = msg_bytes;
 777                         }
 778                         read_loop(fd, iobuf_in, msg_bytes);
 779                         remaining = msg_bytes;
 780                         iobuf_in_ndx = 0;
 781                         break;
 782                 case MSG_DELETED:
 783                         if (msg_bytes >= sizeof line)
 784                                 goto overflow;
 785                         read_loop(fd, line, msg_bytes);
 786                         /* A directory name was sent with the trailing null */
 787                         if (msg_bytes > 0 && !line[msg_bytes-1])
 788                                 log_delete(line, S_IFDIR);
 789                         else {
 790                                 line[msg_bytes] = '\0';
 791                                 log_delete(line, S_IFREG);
 792                         }
 793                         break;
 794                 case MSG_SUCCESS:
 795                         if (msg_bytes != 4) {
 796                                 rprintf(FERROR, "invalid multi-message %d:%ld [%s]\n",
 797                                         tag, (long)msg_bytes, who_am_i());
 798                                 exit_cleanup(RERR_STREAMIO);
 799                         }
 800                         read_loop(fd, line, msg_bytes);
 801                         successful_send(IVAL(line, 0));
 802                         break;
 803                 case MSG_INFO:
 804                 case MSG_ERROR:
 805                         if (msg_bytes >= sizeof line) {
 806                             overflow:
 807                                 rprintf(FERROR,
 808                                         "multiplexing overflow %d:%ld [%s]\n",
 809                                         tag, (long)msg_bytes, who_am_i());
 810                                 exit_cleanup(RERR_STREAMIO);
 811                         }
 812                         read_loop(fd, line, msg_bytes);
 813                         rwrite((enum logcode)tag, line, msg_bytes);
 814                         break;
 815                 default:
 816                         rprintf(FERROR, "unexpected tag %d [%s]\n",
 817                                 tag, who_am_i());
 818                         exit_cleanup(RERR_STREAMIO);
 819                 }
 820         }
 821
 822         if (remaining == 0)
 823                 io_flush(NORMAL_FLUSH);
 824
 825         return cnt;
 826 }
 827
 828 /**
 829  * Do a buffered read from @p fd.  Don't return until all @p n bytes
 830  * have been read.  If all @p n can't be read then exit with an
 831  * error.
 832  **/
 833 static void readfd(int fd, char *buffer, size_t N)
 834 {
 835         int  cnt;
 836         size_t total = 0;
 837
 838         while (total < N) {
 839                 cnt = readfd_unbuffered(fd, buffer + total, N-total);
 840                 total += cnt;
 841         }
 842
 843         if (fd == write_batch_monitor_in) {
 844                 if ((size_t)write(batch_fd, buffer, total) != total)
 845                         exit_cleanup(RERR_FILEIO);
 846         }
 847
 848         if (fd == sock_f_in)
 849                 stats.total_read += total;
 850 }
 851
 852 int read_shortint(int f)
 853 {
 854         uchar b[2];
 855         readfd(f, (char *)b, 2);
 856         return (b[1] << 8) + b[0];
 857 }
 858
 859 int32 read_int(int f)
 860 {
 861         char b[4];
 862         int32 num;
 863
 864         readfd(f,b,4);
 865         num = IVAL(b,0);
 866         if (num == (int32)0xffffffff)
 867                 return -1;
 868         return num;
 869 }
 870
 871 int64 read_longint(int f)
 872 {
 873         int64 num;
 874         char b[8];
 875         num = read_int(f);
 876
 877         if ((int32)num != (int32)0xffffffff)
 878                 return num;
 879
 880 #if SIZEOF_INT64 < 8
 881         rprintf(FERROR, "Integer overflow: attempted 64-bit offset\n");
 882         exit_cleanup(RERR_UNSUPPORTED);
 883 #else
 884         readfd(f,b,8);
 885         num = IVAL(b,0) | (((int64)IVAL(b,4))<<32);
 886 #endif
 887
 888         return num;
 889 }
 890
 891 void read_buf(int f,char *buf,size_t len)
 892 {
 893         readfd(f,buf,len);
 894 }
 895
 896 void read_sbuf(int f,char *buf,size_t len)
 897 {
 898         readfd(f, buf, len);
 899         buf[len] = '\0';
 900 }
 901
 902 uchar read_byte(int f)
 903 {
 904         uchar c;
 905         readfd(f, (char *)&c, 1);
 906         return c;
 907 }
 908
 909 int read_vstring(int f, char *buf, int bufsize)
 910 {
 911         int len = read_byte(f);
 912
 913         if (len & 0x80)
 914                 len = (len & ~0x80) * 0x100 + read_byte(f);
 915
 916         if (len >= bufsize) {
 917                 rprintf(FERROR, "over-long vstring received (%d > %d)\n",
 918                         len, bufsize - 1);
 919                 return -1;
 920         }
 921
 922         if (len)
 923                 readfd(f, buf, len);
 924         buf[len] = '\0';
 925         return len;
 926 }
 927
 928 /* Populate a sum_struct with values from the socket.  This is
 929  * called by both the sender and the receiver. */
 930 void read_sum_head(int f, struct sum_struct *sum)
 931 {
 932         sum->count = read_int(f);
 933         if (sum->count < 0) {
 934                 rprintf(FERROR, "Invalid checksum count %ld [%s]\n",
 935                         (long)sum->count, who_am_i());
 936                 exit_cleanup(RERR_PROTOCOL);
 937         }
 938         sum->blength = read_int(f);
 939         if (sum->blength < 0 || sum->blength > MAX_BLOCK_SIZE) {
 940                 rprintf(FERROR, "Invalid block length %ld [%s]\n",
 941                         (long)sum->blength, who_am_i());
 942                 exit_cleanup(RERR_PROTOCOL);
 943         }
 944         sum->s2length = protocol_version < 27 ? csum_length : (int)read_int(f);
 945         if (sum->s2length < 0 || sum->s2length > MD4_SUM_LENGTH) {
 946                 rprintf(FERROR, "Invalid checksum length %d [%s]\n",
 947                         sum->s2length, who_am_i());
 948                 exit_cleanup(RERR_PROTOCOL);
 949         }
 950         sum->remainder = read_int(f);
 951         if (sum->remainder < 0 || sum->remainder > sum->blength) {
 952                 rprintf(FERROR, "Invalid remainder length %ld [%s]\n",
 953                         (long)sum->remainder, who_am_i());
 954                 exit_cleanup(RERR_PROTOCOL);
 955         }
 956 }
 957
 958 /* Send the values from a sum_struct over the socket.  Set sum to
 959  * NULL if there are no checksums to send.  This is called by both
 960  * the generator and the sender. */
 961 void write_sum_head(int f, struct sum_struct *sum)
 962 {
 963         static struct sum_struct null_sum;
 964
 965         if (sum == NULL)
 966                 sum = &null_sum;
 967
 968         write_int(f, sum->count);
 969         write_int(f, sum->blength);
 970         if (protocol_version >= 27)
 971                 write_int(f, sum->s2length);
 972         write_int(f, sum->remainder);
 973 }
 974
 975 /**
 976  * Sleep after writing to limit I/O bandwidth usage.
 977  *
 978  * @todo Rather than sleeping after each write, it might be better to
 979  * use some kind of averaging.  The current algorithm seems to always
 980  * use a bit less bandwidth than specified, because it doesn't make up
 981  * for slow periods.  But arguably this is a feature.  In addition, we
 982  * ought to take the time used to write the data into account.
 983  *
 984  * During some phases of big transfers (file FOO is uptodate) this is
 985  * called with a small bytes_written every time.  As the kernel has to
 986  * round small waits up to guarantee that we actually wait at least the
 987  * requested number of microseconds, this can become grossly inaccurate.
 988  * We therefore keep track of the bytes we've written over time and only
 989  * sleep when the accumulated delay is at least 1 tenth of a second.
 990  **/
 991 static void sleep_for_bwlimit(int bytes_written)
 992 {
 993         static struct timeval prior_tv;
 994         static long total_written = 0;
 995         struct timeval tv, start_tv;
 996         long elapsed_usec, sleep_usec;
 997
 998 #define ONE_SEC 1000000L /* # of microseconds in a second */
 999
1000         if (!bwlimit_writemax)
1001                 return;
1002
1003         total_written += bytes_written;
1004
1005         gettimeofday(&start_tv, NULL);
1006         if (prior_tv.tv_sec) {
1007                 elapsed_usec = (start_tv.tv_sec - prior_tv.tv_sec) * ONE_SEC
1008                              + (start_tv.tv_usec - prior_tv.tv_usec);
1009                 total_written -= elapsed_usec * bwlimit / (ONE_SEC/1024);
1010                 if (total_written < 0)
1011                         total_written = 0;
1012         }
1013
1014         sleep_usec = total_written * (ONE_SEC/1024) / bwlimit;
1015         if (sleep_usec < ONE_SEC / 10) {
1016                 prior_tv = start_tv;
1017                 return;
1018         }
1019
1020         tv.tv_sec  = sleep_usec / ONE_SEC;
1021         tv.tv_usec = sleep_usec % ONE_SEC;
1022         select(0, NULL, NULL, NULL, &tv);
1023
1024         gettimeofday(&prior_tv, NULL);
1025         elapsed_usec = (prior_tv.tv_sec - start_tv.tv_sec) * ONE_SEC
1026                      + (prior_tv.tv_usec - start_tv.tv_usec);
1027         total_written = (sleep_usec - elapsed_usec) * bwlimit / (ONE_SEC/1024);
1028 }
1029
1030 /* Write len bytes to the file descriptor fd, looping as necessary to get
1031  * the job done and also (in certain circumstances) reading any data on
1032  * msg_fd_in to avoid deadlock.
1033  *
1034  * This function underlies the multiplexing system.  The body of the
1035  * application never calls this function directly. */
1036 static void writefd_unbuffered(int fd,char *buf,size_t len)
1037 {
1038         size_t n, total = 0;
1039         fd_set w_fds, r_fds;
1040         int maxfd, count, cnt, using_r_fds;
1041         int defer_save = defer_forwarding_messages;
1042         struct timeval tv;
1043
1044         no_flush++;
1045
1046         while (total < len) {
1047                 FD_ZERO(&w_fds);
1048                 FD_SET(fd,&w_fds);
1049                 maxfd = fd;
1050
1051                 if (msg_fd_in >= 0) {
1052                         FD_ZERO(&r_fds);
1053                         FD_SET(msg_fd_in,&r_fds);
1054                         if (msg_fd_in > maxfd)
1055                                 maxfd = msg_fd_in;
1056                         using_r_fds = 1;
1057                 } else
1058                         using_r_fds = 0;
1059
1060                 tv.tv_sec = select_timeout;
1061                 tv.tv_usec = 0;
1062
1063                 errno = 0;
1064                 count = select(maxfd + 1, using_r_fds ? &r_fds : NULL,
1065                                &w_fds, NULL, &tv);
1066
1067                 if (count <= 0) {
1068                         if (count < 0 && errno == EBADF)
1069                                 exit_cleanup(RERR_SOCKETIO);
1070                         check_timeout();
1071                         continue;
1072                 }
1073
1074                 if (using_r_fds && FD_ISSET(msg_fd_in, &r_fds))
1075                         read_msg_fd();
1076
1077                 if (!FD_ISSET(fd, &w_fds))
1078                         continue;
1079
1080                 n = len - total;
1081                 if (bwlimit_writemax && n > bwlimit_writemax)
1082                         n = bwlimit_writemax;
1083                 cnt = write(fd, buf + total, n);
1084
1085                 if (cnt <= 0) {
1086                         if (cnt < 0) {
1087                                 if (errno == EINTR)
1088                                         continue;
1089                                 if (errno == EWOULDBLOCK || errno == EAGAIN) {
1090                                         msleep(1);
1091                                         continue;
1092                                 }
1093                         }
1094
1095                         /* Don't try to write errors back across the stream. */
1096                         if (fd == sock_f_out)
1097                                 close_multiplexing_out();
1098                         rsyserr(FERROR, errno,
1099                                 "writefd_unbuffered failed to write %ld bytes [%s]",
1100                                 (long)len, who_am_i());
1101                         /* If the other side is sending us error messages, try
1102                          * to grab any messages they sent before they died. */
1103                         while (fd == sock_f_out && io_multiplexing_in) {
1104                                 set_io_timeout(30);
1105                                 ignore_timeout = 0;
1106                                 readfd_unbuffered(sock_f_in, io_filesfrom_buf,
1107                                                   sizeof io_filesfrom_buf);
1108                         }
1109                         exit_cleanup(RERR_STREAMIO);
1110                 }
1111
1112                 total += cnt;
1113                 defer_forwarding_messages = 1;
1114
1115                 if (fd == sock_f_out) {
1116                         if (io_timeout || am_generator)
1117                                 last_io_out = time(NULL);
1118                         sleep_for_bwlimit(cnt);
1119                 }
1120         }
1121
1122         defer_forwarding_messages = defer_save;
1123         no_flush--;
1124 }
1125
1126 static void msg2sndr_flush(void)
1127 {
1128         if (defer_forwarding_messages)
1129                 return;
1130
1131         while (msg2sndr.head && io_multiplexing_out) {
1132                 struct msg_list_item *m = msg2sndr.head;
1133                 if (!(msg2sndr.head = m->next))
1134                         msg2sndr.tail = NULL;
1135                 stats.total_written += m->len;
1136                 defer_forwarding_messages = 1;
1137                 writefd_unbuffered(sock_f_out, m->buf, m->len);
1138                 defer_forwarding_messages = 0;
1139                 free(m);
1140         }
1141 }
1142
1143 /**
1144  * Write an message to a multiplexed stream. If this fails then rsync
1145  * exits.
1146  **/
1147 static void mplex_write(enum msgcode code, char *buf, size_t len)
1148 {
1149         char buffer[1024];
1150         size_t n = len;
1151
1152         SIVAL(buffer, 0, ((MPLEX_BASE + (int)code)<<24) + len);
1153
1154         if (n > sizeof buffer - 4)
1155                 n = 0;
1156         else
1157                 memcpy(buffer + 4, buf, n);
1158
1159         writefd_unbuffered(sock_f_out, buffer, n+4);
1160
1161         len -= n;
1162         buf += n;
1163
1164         if (len) {
1165                 defer_forwarding_messages = 1;
1166                 writefd_unbuffered(sock_f_out, buf, len);
1167                 defer_forwarding_messages = 0;
1168                 msg2sndr_flush();
1169         }
1170 }
1171
1172 void io_flush(int flush_it_all)
1173 {
1174         msg2genr_flush(flush_it_all);
1175         msg2sndr_flush();
1176
1177         if (!iobuf_out_cnt || no_flush)
1178                 return;
1179
1180         if (io_multiplexing_out)
1181                 mplex_write(MSG_DATA, iobuf_out, iobuf_out_cnt);
1182         else
1183                 writefd_unbuffered(sock_f_out, iobuf_out, iobuf_out_cnt);
1184         iobuf_out_cnt = 0;
1185 }
1186
1187 static void writefd(int fd,char *buf,size_t len)
1188 {
1189         if (fd == msg_fd_out) {
1190                 rprintf(FERROR, "Internal error: wrong write used in receiver.\n");
1191                 exit_cleanup(RERR_PROTOCOL);
1192         }
1193
1194         if (fd == sock_f_out)
1195                 stats.total_written += len;
1196
1197         if (fd == write_batch_monitor_out) {
1198                 if ((size_t)write(batch_fd, buf, len) != len)
1199                         exit_cleanup(RERR_FILEIO);
1200         }
1201
1202         if (!iobuf_out || fd != sock_f_out) {
1203                 writefd_unbuffered(fd, buf, len);
1204                 return;
1205         }
1206
1207         while (len) {
1208                 int n = MIN((int)len, IO_BUFFER_SIZE - iobuf_out_cnt);
1209                 if (n > 0) {
1210                         memcpy(iobuf_out+iobuf_out_cnt, buf, n);
1211                         buf += n;
1212                         len -= n;
1213                         iobuf_out_cnt += n;
1214                 }
1215
1216                 if (iobuf_out_cnt == IO_BUFFER_SIZE)
1217                         io_flush(NORMAL_FLUSH);
1218         }
1219 }
1220
1221 void write_shortint(int f, int x)
1222 {
1223         uchar b[2];
1224         b[0] = x;
1225         b[1] = x >> 8;
1226         writefd(f, (char *)b, 2);
1227 }
1228
1229 void write_int(int f,int32 x)
1230 {
1231         char b[4];
1232         SIVAL(b,0,x);
1233         writefd(f,b,4);
1234 }
1235
1236 /*
1237  * Note: int64 may actually be a 32-bit type if ./configure couldn't find any
1238  * 64-bit types on this platform.
1239  */
1240 void write_longint(int f, int64 x)
1241 {
1242         char b[8];
1243
1244         if (x <= 0x7FFFFFFF) {
1245                 write_int(f, (int)x);
1246                 return;
1247         }
1248
1249 #if SIZEOF_INT64 < 8
1250         rprintf(FERROR, "Integer overflow: attempted 64-bit offset\n");
1251         exit_cleanup(RERR_UNSUPPORTED);
1252 #else
1253         write_int(f, (int32)0xFFFFFFFF);
1254         SIVAL(b,0,(x&0xFFFFFFFF));
1255         SIVAL(b,4,((x>>32)&0xFFFFFFFF));
1256
1257         writefd(f,b,8);
1258 #endif
1259 }
1260
1261 void write_buf(int f,char *buf,size_t len)
1262 {
1263         writefd(f,buf,len);
1264 }
1265
1266 /** Write a string to the connection */
1267 void write_sbuf(int f, char *buf)
1268 {
1269         writefd(f, buf, strlen(buf));
1270 }
1271
1272 void write_byte(int f, uchar c)
1273 {
1274         writefd(f, (char *)&c, 1);
1275 }
1276
1277 void write_vstring(int f, char *str, int len)
1278 {
1279         uchar lenbuf[3], *lb = lenbuf;
1280
1281         if (len > 0x7F) {
1282                 if (len > 0x7FFF) {
1283                         rprintf(FERROR,
1284                                 "attempting to send over-long vstring (%d > %d)\n",
1285                                 len, 0x7FFF);
1286                         exit_cleanup(RERR_PROTOCOL);
1287                 }
1288                 *lb++ = len / 0x100 + 0x80;
1289         }
1290         *lb = len;
1291
1292         writefd(f, (char*)lenbuf, lb - lenbuf + 1);
1293         if (len)
1294                 writefd(f, str, len);
1295 }
1296
1297 /**
1298  * Read a line of up to @p maxlen characters into @p buf (not counting
1299  * the trailing null).  Strips the (required) trailing newline and all
1300  * carriage returns.
1301  *
1302  * @return 1 for success; 0 for I/O error or truncation.
1303  **/
1304 int read_line(int f, char *buf, size_t maxlen)
1305 {
1306         while (maxlen) {
1307                 buf[0] = 0;
1308                 read_buf(f, buf, 1);
1309                 if (buf[0] == 0)
1310                         return 0;
1311                 if (buf[0] == '\n')
1312                         break;
1313                 if (buf[0] != '\r') {
1314                         buf++;
1315                         maxlen--;
1316                 }
1317         }
1318         *buf = '\0';
1319         return maxlen > 0;
1320 }
1321
1322 void io_printf(int fd, const char *format, ...)
1323 {
1324         va_list ap;
1325         char buf[BIGPATHBUFLEN];
1326         int len;
1327
1328         va_start(ap, format);
1329         len = vsnprintf(buf, sizeof buf, format, ap);
1330         va_end(ap);
1331
1332         if (len < 0)
1333                 exit_cleanup(RERR_STREAMIO);
1334
1335         if (len > (int)sizeof buf) {
1336                 rprintf(FERROR, "io_printf() was too long for the buffer.\n");
1337                 exit_cleanup(RERR_STREAMIO);
1338         }
1339
1340         write_sbuf(fd, buf);
1341 }
1342
1343 /** Setup for multiplexing a MSG_* stream with the data stream. */
1344 void io_start_multiplex_out(void)
1345 {
1346         io_flush(NORMAL_FLUSH);
1347         io_start_buffering_out();
1348         io_multiplexing_out = 1;
1349 }
1350
1351 /** Setup for multiplexing a MSG_* stream with the data stream. */
1352 void io_start_multiplex_in(void)
1353 {
1354         io_flush(NORMAL_FLUSH);
1355         io_start_buffering_in();
1356         io_multiplexing_in = 1;
1357 }
1358
1359 /** Write an message to the multiplexed data stream. */
1360 int io_multiplex_write(enum msgcode code, char *buf, size_t len)
1361 {
1362         if (!io_multiplexing_out)
1363                 return 0;
1364
1365         io_flush(NORMAL_FLUSH);
1366         stats.total_written += (len+4);
1367         mplex_write(code, buf, len);
1368         return 1;
1369 }
1370
1371 void close_multiplexing_in(void)
1372 {
1373         io_multiplexing_in = 0;
1374 }
1375
1376 /** Stop output multiplexing. */
1377 void close_multiplexing_out(void)
1378 {
1379         io_multiplexing_out = 0;
1380 }
1381
1382 void start_write_batch(int fd)
1383 {
1384         write_stream_flags(batch_fd);
1385
1386         /* Some communication has already taken place, but we don't
1387          * enable batch writing until here so that we can write a
1388          * canonical record of the communication even though the
1389          * actual communication so far depends on whether a daemon
1390          * is involved. */
1391         write_int(batch_fd, protocol_version);
1392         write_int(batch_fd, checksum_seed);
1393
1394         if (am_sender)
1395                 write_batch_monitor_out = fd;
1396         else
1397                 write_batch_monitor_in = fd;
1398 }
1399
1400 void stop_write_batch(void)
1401 {
1402         write_batch_monitor_out = -1;
1403         write_batch_monitor_in = -1;
1404 }