io.c

   1 /* -*- c-file-style: "linux" -*-
   2  *
   3  * Copyright (C) 1996-2001 by Andrew Tridgell
   4  * Copyright (C) Paul Mackerras 1996
   5  * Copyright (C) 2001, 2002 by Martin Pool <mbp@samba.org>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 /**
  23  * @file io.c
  24  *
  25  * Socket and pipe I/O utilities used in rsync.
  26  *
  27  * rsync provides its own multiplexing system, which is used to send
  28  * stderr and stdout over a single socket.  We need this because
  29  * stdout normally carries the binary data stream, and stderr all our
  30  * error messages.
  31  *
  32  * For historical reasons this is off during the start of the
  33  * connection, but it's switched on quite early using
  34  * io_start_multiplex_out() and io_start_multiplex_in().
  35  **/
  36
  37 #include "rsync.h"
  38
  39 /** If no timeout is specified then use a 60 second select timeout */
  40 #define SELECT_TIMEOUT 60
  41
  42 extern int bwlimit;
  43 extern size_t bwlimit_writemax;
  44 extern int io_timeout;
  45 extern int allowed_lull;
  46 extern int am_server;
  47 extern int am_daemon;
  48 extern int am_sender;
  49 extern int am_generator;
  50 extern int eol_nulls;
  51 extern int read_batch;
  52 extern int csum_length;
  53 extern int checksum_seed;
  54 extern int protocol_version;
  55 extern int remove_sent_files;
  56 extern int preserve_hard_links;
  57 extern char *filesfrom_host;
  58 extern struct stats stats;
  59 extern struct file_list *the_file_list;
  60
  61 const char phase_unknown[] = "unknown";
  62 int ignore_timeout = 0;
  63 int batch_fd = -1;
  64 int batch_gen_fd = -1;
  65
  66 /**
  67  * The connection might be dropped at some point; perhaps because the
  68  * remote instance crashed.  Just giving the offset on the stream is
  69  * not very helpful.  So instead we try to make io_phase_name point to
  70  * something useful.
  71  *
  72  * For buffered/multiplexed I/O these names will be somewhat
  73  * approximate; perhaps for ease of support we would rather make the
  74  * buffer always flush when a single application-level I/O finishes.
  75  *
  76  * @todo Perhaps we want some simple stack functionality, but there's
  77  * no need to overdo it.
  78  **/
  79 const char *io_write_phase = phase_unknown;
  80 const char *io_read_phase = phase_unknown;
  81
  82 /* Ignore an EOF error if non-zero. See whine_about_eof(). */
  83 int kluge_around_eof = 0;
  84
  85 int msg_fd_in = -1;
  86 int msg_fd_out = -1;
  87 int sock_f_in = -1;
  88 int sock_f_out = -1;
  89
  90 static int io_multiplexing_out;
  91 static int io_multiplexing_in;
  92 static time_t last_io_in;
  93 static time_t last_io_out;
  94 static int no_flush;
  95
  96 static int write_batch_monitor_in = -1;
  97 static int write_batch_monitor_out = -1;
  98
  99 static int io_filesfrom_f_in = -1;
 100 static int io_filesfrom_f_out = -1;
 101 static char io_filesfrom_buf[2048];
 102 static char *io_filesfrom_bp;
 103 static char io_filesfrom_lastchar;
 104 static int io_filesfrom_buflen;
 105 static int defer_forwarding_messages = 0;
 106 static int select_timeout = SELECT_TIMEOUT;
 107 static int active_filecnt = 0;
 108 static OFF_T active_bytecnt = 0;
 109
 110 static void read_loop(int fd, char *buf, size_t len);
 111
 112 struct flist_ndx_item {
 113         struct flist_ndx_item *next;
 114         int ndx;
 115 };
 116
 117 struct flist_ndx_list {
 118         struct flist_ndx_item *head, *tail;
 119 };
 120
 121 static struct flist_ndx_list redo_list, hlink_list;
 122
 123 struct msg_list_item {
 124         struct msg_list_item *next;
 125         int len;
 126         char buf[1];
 127 };
 128
 129 struct msg_list {
 130         struct msg_list_item *head, *tail;
 131 };
 132
 133 static struct msg_list msg2genr, msg2sndr;
 134
 135 static void flist_ndx_push(struct flist_ndx_list *lp, int ndx)
 136 {
 137         struct flist_ndx_item *item;
 138
 139         if (!(item = new(struct flist_ndx_item)))
 140                 out_of_memory("flist_ndx_push");
 141         item->next = NULL;
 142         item->ndx = ndx;
 143         if (lp->tail)
 144                 lp->tail->next = item;
 145         else
 146                 lp->head = item;
 147         lp->tail = item;
 148 }
 149
 150 static int flist_ndx_pop(struct flist_ndx_list *lp)
 151 {
 152         struct flist_ndx_item *next;
 153         int ndx;
 154
 155         if (!lp->head)
 156                 return -1;
 157
 158         ndx = lp->head->ndx;
 159         next = lp->head->next;
 160         free(lp->head);
 161         lp->head = next;
 162         if (!next)
 163                 lp->tail = NULL;
 164
 165         return ndx;
 166 }
 167
 168 static void check_timeout(void)
 169 {
 170         time_t t;
 171
 172         if (!io_timeout || ignore_timeout)
 173                 return;
 174
 175         if (!last_io_in) {
 176                 last_io_in = time(NULL);
 177                 return;
 178         }
 179
 180         t = time(NULL);
 181
 182         if (t - last_io_in >= io_timeout) {
 183                 if (!am_server && !am_daemon) {
 184                         rprintf(FERROR, "io timeout after %d seconds -- exiting\n",
 185                                 (int)(t-last_io_in));
 186                 }
 187                 exit_cleanup(RERR_TIMEOUT);
 188         }
 189 }
 190
 191 /* Note the fds used for the main socket (which might really be a pipe
 192  * for a local transfer, but we can ignore that). */
 193 void io_set_sock_fds(int f_in, int f_out)
 194 {
 195         sock_f_in = f_in;
 196         sock_f_out = f_out;
 197 }
 198
 199 void set_io_timeout(int secs)
 200 {
 201         io_timeout = secs;
 202
 203         if (!io_timeout || io_timeout > SELECT_TIMEOUT)
 204                 select_timeout = SELECT_TIMEOUT;
 205         else
 206                 select_timeout = io_timeout;
 207
 208         allowed_lull = read_batch ? 0 : (io_timeout + 1) / 2;
 209 }
 210
 211 /* Setup the fd used to receive MSG_* messages.  Only needed during the
 212  * early stages of being a local sender (up through the sending of the
 213  * file list) or when we're the generator (to fetch the messages from
 214  * the receiver). */
 215 void set_msg_fd_in(int fd)
 216 {
 217         msg_fd_in = fd;
 218 }
 219
 220 /* Setup the fd used to send our MSG_* messages.  Only needed when
 221  * we're the receiver (to send our messages to the generator). */
 222 void set_msg_fd_out(int fd)
 223 {
 224         msg_fd_out = fd;
 225         set_nonblocking(msg_fd_out);
 226 }
 227
 228 /* Add a message to the pending MSG_* list. */
 229 static void msg_list_add(struct msg_list *lst, int code, char *buf, int len)
 230 {
 231         struct msg_list_item *m;
 232         int sz = len + 4 + sizeof m[0] - 1;
 233
 234         if (!(m = (struct msg_list_item *)new_array(char, sz)))
 235                 out_of_memory("msg_list_add");
 236         m->next = NULL;
 237         m->len = len + 4;
 238         SIVAL(m->buf, 0, ((code+MPLEX_BASE)<<24) | len);
 239         memcpy(m->buf + 4, buf, len);
 240         if (lst->tail)
 241                 lst->tail->next = m;
 242         else
 243                 lst->head = m;
 244         lst->tail = m;
 245 }
 246
 247 /* Read a message from the MSG_* fd and handle it.  This is called either
 248  * during the early stages of being a local sender (up through the sending
 249  * of the file list) or when we're the generator (to fetch the messages
 250  * from the receiver). */
 251 static void read_msg_fd(void)
 252 {
 253         char buf[2048];
 254         size_t n;
 255         int fd = msg_fd_in;
 256         int tag, len;
 257
 258         /* Temporarily disable msg_fd_in.  This is needed to avoid looping back
 259          * to this routine from writefd_unbuffered(). */
 260         msg_fd_in = -1;
 261
 262         read_loop(fd, buf, 4);
 263         tag = IVAL(buf, 0);
 264
 265         len = tag & 0xFFFFFF;
 266         tag = (tag >> 24) - MPLEX_BASE;
 267
 268         switch (tag) {
 269         case MSG_DONE:
 270                 if (len != 0 || !am_generator) {
 271                         rprintf(FERROR, "invalid message %d:%d\n", tag, len);
 272                         exit_cleanup(RERR_STREAMIO);
 273                 }
 274                 flist_ndx_push(&redo_list, -1);
 275                 break;
 276         case MSG_REDO:
 277                 if (len != 4 || !am_generator) {
 278                         rprintf(FERROR, "invalid message %d:%d\n", tag, len);
 279                         exit_cleanup(RERR_STREAMIO);
 280                 }
 281                 read_loop(fd, buf, 4);
 282                 if (remove_sent_files)
 283                         decrement_active_files(IVAL(buf,0));
 284                 flist_ndx_push(&redo_list, IVAL(buf,0));
 285                 break;
 286         case MSG_DELETED:
 287                 if (len >= (int)sizeof buf || !am_generator) {
 288                         rprintf(FERROR, "invalid message %d:%d\n", tag, len);
 289                         exit_cleanup(RERR_STREAMIO);
 290                 }
 291                 read_loop(fd, buf, len);
 292                 if (defer_forwarding_messages)
 293                         msg_list_add(&msg2sndr, MSG_DELETED, buf, len);
 294                 else
 295                         io_multiplex_write(MSG_DELETED, buf, len);
 296                 break;
 297         case MSG_SUCCESS:
 298                 if (len != 4 || !am_generator) {
 299                         rprintf(FERROR, "invalid message %d:%d\n", tag, len);
 300                         exit_cleanup(RERR_STREAMIO);
 301                 }
 302                 read_loop(fd, buf, len);
 303                 if (remove_sent_files) {
 304                         decrement_active_files(IVAL(buf,0));
 305                         if (defer_forwarding_messages)
 306                                 msg_list_add(&msg2sndr, MSG_SUCCESS, buf, len);
 307                         else
 308                                 io_multiplex_write(MSG_SUCCESS, buf, len);
 309                 }
 310                 if (preserve_hard_links)
 311                         flist_ndx_push(&hlink_list, IVAL(buf,0));
 312                 break;
 313         case MSG_SOCKERR:
 314                 if (!am_generator) {
 315                         rprintf(FERROR, "invalid message %d:%d\n", tag, len);
 316                         exit_cleanup(RERR_STREAMIO);
 317                 }
 318                 close_multiplexing_out();
 319                 /* FALL THROUGH */
 320         case MSG_INFO:
 321         case MSG_ERROR:
 322         case MSG_LOG:
 323                 while (len) {
 324                         n = len;
 325                         if (n >= sizeof buf)
 326                                 n = sizeof buf - 1;
 327                         read_loop(fd, buf, n);
 328                         if (am_generator && am_server && defer_forwarding_messages)
 329                                 msg_list_add(&msg2sndr, tag, buf, n);
 330                         else
 331                                 rwrite((enum logcode)tag, buf, n);
 332                         len -= n;
 333                 }
 334                 break;
 335         default:
 336                 rprintf(FERROR, "unknown message %d:%d [%s]\n",
 337                         tag, len, who_am_i());
 338                 exit_cleanup(RERR_STREAMIO);
 339         }
 340
 341         msg_fd_in = fd;
 342 }
 343
 344 /* This is used by the generator to limit how many file transfers can
 345  * be active at once when --remove-sent-files is specified.  Without
 346  * this, sender-side deletions were mostly happening at the end. */
 347 void increment_active_files(int ndx, int itemizing, enum logcode code)
 348 {
 349         /* TODO: tune these limits? */
 350         while (active_filecnt >= (active_bytecnt >= 128*1024 ? 10 : 50)) {
 351                 if (hlink_list.head)
 352                         check_for_finished_hlinks(itemizing, code);
 353                 read_msg_fd();
 354         }
 355
 356         active_filecnt++;
 357         active_bytecnt += the_file_list->files[ndx]->length;
 358 }
 359
 360 void decrement_active_files(int ndx)
 361 {
 362         active_filecnt--;
 363         active_bytecnt -= the_file_list->files[ndx]->length;
 364 }
 365
 366 /* Try to push messages off the list onto the wire.  If we leave with more
 367  * to do, return 0.  On error, return -1.  If everything flushed, return 1.
 368  * This is only active in the receiver. */
 369 static int msg2genr_flush(int flush_it_all)
 370 {
 371         static int written = 0;
 372         struct timeval tv;
 373         fd_set fds;
 374
 375         if (msg_fd_out < 0)
 376                 return -1;
 377
 378         while (msg2genr.head) {
 379                 struct msg_list_item *m = msg2genr.head;
 380                 int n = write(msg_fd_out, m->buf + written, m->len - written);
 381                 if (n < 0) {
 382                         if (errno == EINTR)
 383                                 continue;
 384                         if (errno != EWOULDBLOCK && errno != EAGAIN)
 385                                 return -1;
 386                         if (!flush_it_all)
 387                                 return 0;
 388                         FD_ZERO(&fds);
 389                         FD_SET(msg_fd_out, &fds);
 390                         tv.tv_sec = select_timeout;
 391                         tv.tv_usec = 0;
 392                         if (!select(msg_fd_out+1, NULL, &fds, NULL, &tv))
 393                                 check_timeout();
 394                 } else if ((written += n) == m->len) {
 395                         msg2genr.head = m->next;
 396                         if (!msg2genr.head)
 397                                 msg2genr.tail = NULL;
 398                         free(m);
 399                         written = 0;
 400                 }
 401         }
 402         return 1;
 403 }
 404
 405 void send_msg(enum msgcode code, char *buf, int len)
 406 {
 407         if (msg_fd_out < 0) {
 408                 io_multiplex_write(code, buf, len);
 409                 return;
 410         }
 411         msg_list_add(&msg2genr, code, buf, len);
 412         msg2genr_flush(NORMAL_FLUSH);
 413 }
 414
 415 int get_redo_num(int itemizing, enum logcode code)
 416 {
 417         while (1) {
 418                 if (hlink_list.head)
 419                         check_for_finished_hlinks(itemizing, code);
 420                 if (redo_list.head)
 421                         break;
 422                 read_msg_fd();
 423         }
 424
 425         return flist_ndx_pop(&redo_list);
 426 }
 427
 428 int get_hlink_num(void)
 429 {
 430         return flist_ndx_pop(&hlink_list);
 431 }
 432
 433 /**
 434  * When we're the receiver and we have a local --files-from list of names
 435  * that needs to be sent over the socket to the sender, we have to do two
 436  * things at the same time: send the sender a list of what files we're
 437  * processing and read the incoming file+info list from the sender.  We do
 438  * this by augmenting the read_timeout() function to copy this data.  It
 439  * uses the io_filesfrom_buf to read a block of data from f_in (when it is
 440  * ready, since it might be a pipe) and then blast it out f_out (when it
 441  * is ready to receive more data).
 442  */
 443 void io_set_filesfrom_fds(int f_in, int f_out)
 444 {
 445         io_filesfrom_f_in = f_in;
 446         io_filesfrom_f_out = f_out;
 447         io_filesfrom_bp = io_filesfrom_buf;
 448         io_filesfrom_lastchar = '\0';
 449         io_filesfrom_buflen = 0;
 450 }
 451
 452 /* It's almost always an error to get an EOF when we're trying to read from the
 453  * network, because the protocol is (for the most part) self-terminating.
 454  *
 455  * There is one case for the receiver when it is at the end of the transfer
 456  * (hanging around reading any keep-alive packets that might come its way): if
 457  * the sender dies before the generator's kill-signal comes through, we can end
 458  * up here needing to loop until the kill-signal arrives.  In this situation,
 459  * kluge_around_eof will be < 0.
 460  *
 461  * There is another case for older protocol versions (< 24) where the module
 462  * listing was not terminated, so we must ignore an EOF error in that case and
 463  * exit.  In this situation, kluge_around_eof will be > 0. */
 464 static void whine_about_eof(int fd)
 465 {
 466         if (kluge_around_eof && fd == sock_f_in) {
 467                 int i;
 468                 if (kluge_around_eof > 0)
 469                         exit_cleanup(0);
 470                 /* If we're still here after 10 seconds, exit with an error. */
 471                 for (i = 10*1000/20; i--; )
 472                         msleep(20);
 473         }
 474
 475         rprintf(FERROR, RSYNC_NAME ": connection unexpectedly closed "
 476                 "(%.0f bytes received so far) [%s]\n",
 477                 (double)stats.total_read, who_am_i());
 478
 479         exit_cleanup(RERR_STREAMIO);
 480 }
 481
 482 /**
 483  * Read from a socket with I/O timeout. return the number of bytes
 484  * read. If no bytes can be read then exit, never return a number <= 0.
 485  *
 486  * TODO: If the remote shell connection fails, then current versions
 487  * actually report an "unexpected EOF" error here.  Since it's a
 488  * fairly common mistake to try to use rsh when ssh is required, we
 489  * should trap that: if we fail to read any data at all, we should
 490  * give a better explanation.  We can tell whether the connection has
 491  * started by looking e.g. at whether the remote version is known yet.
 492  */
 493 static int read_timeout(int fd, char *buf, size_t len)
 494 {
 495         int n, cnt = 0;
 496
 497         io_flush(NORMAL_FLUSH);
 498
 499         while (cnt == 0) {
 500                 /* until we manage to read *something* */
 501                 fd_set r_fds, w_fds;
 502                 struct timeval tv;
 503                 int maxfd = fd;
 504                 int count;
 505
 506                 FD_ZERO(&r_fds);
 507                 FD_ZERO(&w_fds);
 508                 FD_SET(fd, &r_fds);
 509                 if (msg2genr.head) {
 510                         FD_SET(msg_fd_out, &w_fds);
 511                         if (msg_fd_out > maxfd)
 512                                 maxfd = msg_fd_out;
 513                 }
 514                 if (io_filesfrom_f_out >= 0) {
 515                         int new_fd;
 516                         if (io_filesfrom_buflen == 0) {
 517                                 if (io_filesfrom_f_in >= 0) {
 518                                         FD_SET(io_filesfrom_f_in, &r_fds);
 519                                         new_fd = io_filesfrom_f_in;
 520                                 } else {
 521                                         io_filesfrom_f_out = -1;
 522                                         new_fd = -1;
 523                                 }
 524                         } else {
 525                                 FD_SET(io_filesfrom_f_out, &w_fds);
 526                                 new_fd = io_filesfrom_f_out;
 527                         }
 528                         if (new_fd > maxfd)
 529                                 maxfd = new_fd;
 530                 }
 531
 532                 tv.tv_sec = select_timeout;
 533                 tv.tv_usec = 0;
 534
 535                 errno = 0;
 536
 537                 count = select(maxfd + 1, &r_fds, &w_fds, NULL, &tv);
 538
 539                 if (count <= 0) {
 540                         if (errno == EBADF)
 541                                 exit_cleanup(RERR_SOCKETIO);
 542                         check_timeout();
 543                         continue;
 544                 }
 545
 546                 if (msg2genr.head && FD_ISSET(msg_fd_out, &w_fds))
 547                         msg2genr_flush(NORMAL_FLUSH);
 548
 549                 if (io_filesfrom_f_out >= 0) {
 550                         if (io_filesfrom_buflen) {
 551                                 if (FD_ISSET(io_filesfrom_f_out, &w_fds)) {
 552                                         int l = write(io_filesfrom_f_out,
 553                                                       io_filesfrom_bp,
 554                                                       io_filesfrom_buflen);
 555                                         if (l > 0) {
 556                                                 if (!(io_filesfrom_buflen -= l))
 557                                                         io_filesfrom_bp = io_filesfrom_buf;
 558                                                 else
 559                                                         io_filesfrom_bp += l;
 560                                         } else {
 561                                                 /* XXX should we complain? */
 562                                                 io_filesfrom_f_out = -1;
 563                                         }
 564                                 }
 565                         } else if (io_filesfrom_f_in >= 0) {
 566                                 if (FD_ISSET(io_filesfrom_f_in, &r_fds)) {
 567                                         int l = read(io_filesfrom_f_in,
 568                                                      io_filesfrom_buf,
 569                                                      sizeof io_filesfrom_buf);
 570                                         if (l <= 0) {
 571                                                 /* Send end-of-file marker */
 572                                                 io_filesfrom_buf[0] = '\0';
 573                                                 io_filesfrom_buf[1] = '\0';
 574                                                 io_filesfrom_buflen = io_filesfrom_lastchar? 2 : 1;
 575                                                 io_filesfrom_f_in = -1;
 576                                         } else {
 577                                                 if (!eol_nulls) {
 578                                                         char *s = io_filesfrom_buf + l;
 579                                                         /* Transform CR and/or LF into '\0' */
 580                                                         while (s-- > io_filesfrom_buf) {
 581                                                                 if (*s == '\n' || *s == '\r')
 582                                                                         *s = '\0';
 583                                                         }
 584                                                 }
 585                                                 if (!io_filesfrom_lastchar) {
 586                                                         /* Last buf ended with a '\0', so don't
 587                                                          * let this buf start with one. */
 588                                                         while (l && !*io_filesfrom_bp)
 589                                                                 io_filesfrom_bp++, l--;
 590                                                 }
 591                                                 if (!l)
 592                                                         io_filesfrom_bp = io_filesfrom_buf;
 593                                                 else {
 594                                                         char *f = io_filesfrom_bp;
 595                                                         char *t = f;
 596                                                         char *eob = f + l;
 597                                                         /* Eliminate any multi-'\0' runs. */
 598                                                         while (f != eob) {
 599                                                                 if (!(*t++ = *f++)) {
 600                                                                         while (f != eob && !*f)
 601                                                                                 f++, l--;
 602                                                                 }
 603                                                         }
 604                                                         io_filesfrom_lastchar = f[-1];
 605                                                 }
 606                                                 io_filesfrom_buflen = l;
 607                                         }
 608                                 }
 609                         }
 610                 }
 611
 612                 if (!FD_ISSET(fd, &r_fds))
 613                         continue;
 614
 615                 n = read(fd, buf, len);
 616
 617                 if (n <= 0) {
 618                         if (n == 0)
 619                                 whine_about_eof(fd); /* Doesn't return. */
 620                         if (errno == EINTR || errno == EWOULDBLOCK
 621                             || errno == EAGAIN)
 622                                 continue;
 623
 624                         /* Don't write errors on a dead socket. */
 625                         if (fd == sock_f_in) {
 626                                 close_multiplexing_out();
 627                                 rsyserr(FSOCKERR, errno, "read error");
 628                         } else
 629                                 rsyserr(FERROR, errno, "read error");
 630                         exit_cleanup(RERR_STREAMIO);
 631                 }
 632
 633                 buf += n;
 634                 len -= n;
 635                 cnt += n;
 636
 637                 if (fd == sock_f_in && io_timeout)
 638                         last_io_in = time(NULL);
 639         }
 640
 641         return cnt;
 642 }
 643
 644 /**
 645  * Read a line into the "fname" buffer (which must be at least MAXPATHLEN
 646  * characters long).
 647  */
 648 int read_filesfrom_line(int fd, char *fname)
 649 {
 650         char ch, *s, *eob = fname + MAXPATHLEN - 1;
 651         int cnt;
 652         int reading_remotely = filesfrom_host != NULL;
 653         int nulls = eol_nulls || reading_remotely;
 654
 655   start:
 656         s = fname;
 657         while (1) {
 658                 cnt = read(fd, &ch, 1);
 659                 if (cnt < 0 && (errno == EWOULDBLOCK
 660                   || errno == EINTR || errno == EAGAIN)) {
 661                         struct timeval tv;
 662                         fd_set fds;
 663                         FD_ZERO(&fds);
 664                         FD_SET(fd, &fds);
 665                         tv.tv_sec = select_timeout;
 666                         tv.tv_usec = 0;
 667                         if (!select(fd+1, &fds, NULL, NULL, &tv))
 668                                 check_timeout();
 669                         continue;
 670                 }
 671                 if (cnt != 1)
 672                         break;
 673                 if (nulls? !ch : (ch == '\r' || ch == '\n')) {
 674                         /* Skip empty lines if reading locally. */
 675                         if (!reading_remotely && s == fname)
 676                                 continue;
 677                         break;
 678                 }
 679                 if (s < eob)
 680                         *s++ = ch;
 681         }
 682         *s = '\0';
 683
 684         /* Dump comments. */
 685         if (*fname == '#' || *fname == ';')
 686                 goto start;
 687
 688         return s - fname;
 689 }
 690
 691 static char *iobuf_out;
 692 static int iobuf_out_cnt;
 693
 694 void io_start_buffering_out(void)
 695 {
 696         if (iobuf_out)
 697                 return;
 698         if (!(iobuf_out = new_array(char, IO_BUFFER_SIZE)))
 699                 out_of_memory("io_start_buffering_out");
 700         iobuf_out_cnt = 0;
 701 }
 702
 703 static char *iobuf_in;
 704 static size_t iobuf_in_siz;
 705
 706 void io_start_buffering_in(void)
 707 {
 708         if (iobuf_in)
 709                 return;
 710         iobuf_in_siz = 2 * IO_BUFFER_SIZE;
 711         if (!(iobuf_in = new_array(char, iobuf_in_siz)))
 712                 out_of_memory("io_start_buffering_in");
 713 }
 714
 715 void io_end_buffering(void)
 716 {
 717         io_flush(NORMAL_FLUSH);
 718         if (!io_multiplexing_out) {
 719                 free(iobuf_out);
 720                 iobuf_out = NULL;
 721         }
 722 }
 723
 724 void maybe_flush_socket(void)
 725 {
 726         if (iobuf_out && iobuf_out_cnt && time(NULL) - last_io_out >= 5)
 727                 io_flush(NORMAL_FLUSH);
 728 }
 729
 730 void maybe_send_keepalive(void)
 731 {
 732         if (time(NULL) - last_io_out >= allowed_lull) {
 733                 if (!iobuf_out || !iobuf_out_cnt) {
 734                         if (protocol_version < 29)
 735                                 return; /* there's nothing we can do */
 736                         write_int(sock_f_out, the_file_list->count);
 737                         write_shortint(sock_f_out, ITEM_IS_NEW);
 738                 }
 739                 if (iobuf_out)
 740                         io_flush(NORMAL_FLUSH);
 741         }
 742 }
 743
 744 /**
 745  * Continue trying to read len bytes - don't return until len has been
 746  * read.
 747  **/
 748 static void read_loop(int fd, char *buf, size_t len)
 749 {
 750         while (len) {
 751                 int n = read_timeout(fd, buf, len);
 752
 753                 buf += n;
 754                 len -= n;
 755         }
 756 }
 757
 758 /**
 759  * Read from the file descriptor handling multiplexing - return number
 760  * of bytes read.
 761  *
 762  * Never returns <= 0.
 763  */
 764 static int readfd_unbuffered(int fd, char *buf, size_t len)
 765 {
 766         static size_t remaining;
 767         static size_t iobuf_in_ndx;
 768         size_t msg_bytes;
 769         int tag, cnt = 0;
 770         char line[BIGPATHBUFLEN];
 771
 772         if (!iobuf_in || fd != sock_f_in)
 773                 return read_timeout(fd, buf, len);
 774
 775         if (!io_multiplexing_in && remaining == 0) {
 776                 remaining = read_timeout(fd, iobuf_in, iobuf_in_siz);
 777                 iobuf_in_ndx = 0;
 778         }
 779
 780         while (cnt == 0) {
 781                 if (remaining) {
 782                         len = MIN(len, remaining);
 783                         memcpy(buf, iobuf_in + iobuf_in_ndx, len);
 784                         iobuf_in_ndx += len;
 785                         remaining -= len;
 786                         cnt = len;
 787                         break;
 788                 }
 789
 790                 read_loop(fd, line, 4);
 791                 tag = IVAL(line, 0);
 792
 793                 msg_bytes = tag & 0xFFFFFF;
 794                 tag = (tag >> 24) - MPLEX_BASE;
 795
 796                 switch (tag) {
 797                 case MSG_DATA:
 798                         if (msg_bytes > iobuf_in_siz) {
 799                                 if (!(iobuf_in = realloc_array(iobuf_in, char,
 800                                                                msg_bytes)))
 801                                         out_of_memory("readfd_unbuffered");
 802                                 iobuf_in_siz = msg_bytes;
 803                         }
 804                         read_loop(fd, iobuf_in, msg_bytes);
 805                         remaining = msg_bytes;
 806                         iobuf_in_ndx = 0;
 807                         break;
 808                 case MSG_DELETED:
 809                         if (msg_bytes >= sizeof line)
 810                                 goto overflow;
 811                         read_loop(fd, line, msg_bytes);
 812                         /* A directory name was sent with the trailing null */
 813                         if (msg_bytes > 0 && !line[msg_bytes-1])
 814                                 log_delete(line, S_IFDIR);
 815                         else {
 816                                 line[msg_bytes] = '\0';
 817                                 log_delete(line, S_IFREG);
 818                         }
 819                         break;
 820                 case MSG_SUCCESS:
 821                         if (msg_bytes != 4) {
 822                                 rprintf(FERROR, "invalid multi-message %d:%ld [%s]\n",
 823                                         tag, (long)msg_bytes, who_am_i());
 824                                 exit_cleanup(RERR_STREAMIO);
 825                         }
 826                         read_loop(fd, line, msg_bytes);
 827                         successful_send(IVAL(line, 0));
 828                         break;
 829                 case MSG_INFO:
 830                 case MSG_ERROR:
 831                         if (msg_bytes >= sizeof line) {
 832                             overflow:
 833                                 rprintf(FERROR,
 834                                         "multiplexing overflow %d:%ld [%s]\n",
 835                                         tag, (long)msg_bytes, who_am_i());
 836                                 exit_cleanup(RERR_STREAMIO);
 837                         }
 838                         read_loop(fd, line, msg_bytes);
 839                         rwrite((enum logcode)tag, line, msg_bytes);
 840                         break;
 841                 default:
 842                         rprintf(FERROR, "unexpected tag %d [%s]\n",
 843                                 tag, who_am_i());
 844                         exit_cleanup(RERR_STREAMIO);
 845                 }
 846         }
 847
 848         if (remaining == 0)
 849                 io_flush(NORMAL_FLUSH);
 850
 851         return cnt;
 852 }
 853
 854 /**
 855  * Do a buffered read from @p fd.  Don't return until all @p n bytes
 856  * have been read.  If all @p n can't be read then exit with an
 857  * error.
 858  **/
 859 static void readfd(int fd, char *buffer, size_t N)
 860 {
 861         int  cnt;
 862         size_t total = 0;
 863
 864         while (total < N) {
 865                 cnt = readfd_unbuffered(fd, buffer + total, N-total);
 866                 total += cnt;
 867         }
 868
 869         if (fd == write_batch_monitor_in) {
 870                 if ((size_t)write(batch_fd, buffer, total) != total)
 871                         exit_cleanup(RERR_FILEIO);
 872         }
 873
 874         if (fd == sock_f_in)
 875                 stats.total_read += total;
 876 }
 877
 878 int read_shortint(int f)
 879 {
 880         uchar b[2];
 881         readfd(f, (char *)b, 2);
 882         return (b[1] << 8) + b[0];
 883 }
 884
 885 int32 read_int(int f)
 886 {
 887         char b[4];
 888         int32 num;
 889
 890         readfd(f,b,4);
 891         num = IVAL(b,0);
 892         if (num == (int32)0xffffffff)
 893                 return -1;
 894         return num;
 895 }
 896
 897 int64 read_longint(int f)
 898 {
 899         int64 num;
 900         char b[8];
 901         num = read_int(f);
 902
 903         if ((int32)num != (int32)0xffffffff)
 904                 return num;
 905
 906 #if SIZEOF_INT64 < 8
 907         rprintf(FERROR, "Integer overflow: attempted 64-bit offset\n");
 908         exit_cleanup(RERR_UNSUPPORTED);
 909 #else
 910         readfd(f,b,8);
 911         num = IVAL(b,0) | (((int64)IVAL(b,4))<<32);
 912 #endif
 913
 914         return num;
 915 }
 916
 917 void read_buf(int f,char *buf,size_t len)
 918 {
 919         readfd(f,buf,len);
 920 }
 921
 922 void read_sbuf(int f,char *buf,size_t len)
 923 {
 924         readfd(f, buf, len);
 925         buf[len] = '\0';
 926 }
 927
 928 uchar read_byte(int f)
 929 {
 930         uchar c;
 931         readfd(f, (char *)&c, 1);
 932         return c;
 933 }
 934
 935 int read_vstring(int f, char *buf, int bufsize)
 936 {
 937         int len = read_byte(f);
 938
 939         if (len & 0x80)
 940                 len = (len & ~0x80) * 0x100 + read_byte(f);
 941
 942         if (len >= bufsize) {
 943                 rprintf(FERROR, "over-long vstring received (%d > %d)\n",
 944                         len, bufsize - 1);
 945                 return -1;
 946         }
 947
 948         if (len)
 949                 readfd(f, buf, len);
 950         buf[len] = '\0';
 951         return len;
 952 }
 953
 954 /* Populate a sum_struct with values from the socket.  This is
 955  * called by both the sender and the receiver. */
 956 void read_sum_head(int f, struct sum_struct *sum)
 957 {
 958         sum->count = read_int(f);
 959         if (sum->count < 0) {
 960                 rprintf(FERROR, "Invalid checksum count %ld [%s]\n",
 961                         (long)sum->count, who_am_i());
 962                 exit_cleanup(RERR_PROTOCOL);
 963         }
 964         sum->blength = read_int(f);
 965         if (sum->blength < 0 || sum->blength > MAX_BLOCK_SIZE) {
 966                 rprintf(FERROR, "Invalid block length %ld [%s]\n",
 967                         (long)sum->blength, who_am_i());
 968                 exit_cleanup(RERR_PROTOCOL);
 969         }
 970         sum->s2length = protocol_version < 27 ? csum_length : (int)read_int(f);
 971         if (sum->s2length < 0 || sum->s2length > MD4_SUM_LENGTH) {
 972                 rprintf(FERROR, "Invalid checksum length %d [%s]\n",
 973                         sum->s2length, who_am_i());
 974                 exit_cleanup(RERR_PROTOCOL);
 975         }
 976         sum->remainder = read_int(f);
 977         if (sum->remainder < 0 || sum->remainder > sum->blength) {
 978                 rprintf(FERROR, "Invalid remainder length %ld [%s]\n",
 979                         (long)sum->remainder, who_am_i());
 980                 exit_cleanup(RERR_PROTOCOL);
 981         }
 982 }
 983
 984 /* Send the values from a sum_struct over the socket.  Set sum to
 985  * NULL if there are no checksums to send.  This is called by both
 986  * the generator and the sender. */
 987 void write_sum_head(int f, struct sum_struct *sum)
 988 {
 989         static struct sum_struct null_sum;
 990
 991         if (sum == NULL)
 992                 sum = &null_sum;
 993
 994         write_int(f, sum->count);
 995         write_int(f, sum->blength);
 996         if (protocol_version >= 27)
 997                 write_int(f, sum->s2length);
 998         write_int(f, sum->remainder);
 999 }
1000
1001 /**
1002  * Sleep after writing to limit I/O bandwidth usage.
1003  *
1004  * @todo Rather than sleeping after each write, it might be better to
1005  * use some kind of averaging.  The current algorithm seems to always
1006  * use a bit less bandwidth than specified, because it doesn't make up
1007  * for slow periods.  But arguably this is a feature.  In addition, we
1008  * ought to take the time used to write the data into account.
1009  *
1010  * During some phases of big transfers (file FOO is uptodate) this is
1011  * called with a small bytes_written every time.  As the kernel has to
1012  * round small waits up to guarantee that we actually wait at least the
1013  * requested number of microseconds, this can become grossly inaccurate.
1014  * We therefore keep track of the bytes we've written over time and only
1015  * sleep when the accumulated delay is at least 1 tenth of a second.
1016  **/
1017 static void sleep_for_bwlimit(int bytes_written)
1018 {
1019         static struct timeval prior_tv;
1020         static long total_written = 0;
1021         struct timeval tv, start_tv;
1022         long elapsed_usec, sleep_usec;
1023
1024 #define ONE_SEC 1000000L /* # of microseconds in a second */
1025
1026         if (!bwlimit_writemax)
1027                 return;
1028
1029         total_written += bytes_written;
1030
1031         gettimeofday(&start_tv, NULL);
1032         if (prior_tv.tv_sec) {
1033                 elapsed_usec = (start_tv.tv_sec - prior_tv.tv_sec) * ONE_SEC
1034                              + (start_tv.tv_usec - prior_tv.tv_usec);
1035                 total_written -= elapsed_usec * bwlimit / (ONE_SEC/1024);
1036                 if (total_written < 0)
1037                         total_written = 0;
1038         }
1039
1040         sleep_usec = total_written * (ONE_SEC/1024) / bwlimit;
1041         if (sleep_usec < ONE_SEC / 10) {
1042                 prior_tv = start_tv;
1043                 return;
1044         }
1045
1046         tv.tv_sec  = sleep_usec / ONE_SEC;
1047         tv.tv_usec = sleep_usec % ONE_SEC;
1048         select(0, NULL, NULL, NULL, &tv);
1049
1050         gettimeofday(&prior_tv, NULL);
1051         elapsed_usec = (prior_tv.tv_sec - start_tv.tv_sec) * ONE_SEC
1052                      + (prior_tv.tv_usec - start_tv.tv_usec);
1053         total_written = (sleep_usec - elapsed_usec) * bwlimit / (ONE_SEC/1024);
1054 }
1055
1056 /* Write len bytes to the file descriptor fd, looping as necessary to get
1057  * the job done and also (in certain circumstances) reading any data on
1058  * msg_fd_in to avoid deadlock.
1059  *
1060  * This function underlies the multiplexing system.  The body of the
1061  * application never calls this function directly. */
1062 static void writefd_unbuffered(int fd,char *buf,size_t len)
1063 {
1064         size_t n, total = 0;
1065         fd_set w_fds, r_fds;
1066         int maxfd, count, cnt, using_r_fds;
1067         int defer_save = defer_forwarding_messages;
1068         struct timeval tv;
1069
1070         no_flush++;
1071
1072         while (total < len) {
1073                 FD_ZERO(&w_fds);
1074                 FD_SET(fd,&w_fds);
1075                 maxfd = fd;
1076
1077                 if (msg_fd_in >= 0) {
1078                         FD_ZERO(&r_fds);
1079                         FD_SET(msg_fd_in,&r_fds);
1080                         if (msg_fd_in > maxfd)
1081                                 maxfd = msg_fd_in;
1082                         using_r_fds = 1;
1083                 } else
1084                         using_r_fds = 0;
1085
1086                 tv.tv_sec = select_timeout;
1087                 tv.tv_usec = 0;
1088
1089                 errno = 0;
1090                 count = select(maxfd + 1, using_r_fds ? &r_fds : NULL,
1091                                &w_fds, NULL, &tv);
1092
1093                 if (count <= 0) {
1094                         if (count < 0 && errno == EBADF)
1095                                 exit_cleanup(RERR_SOCKETIO);
1096                         check_timeout();
1097                         continue;
1098                 }
1099
1100                 if (using_r_fds && FD_ISSET(msg_fd_in, &r_fds))
1101                         read_msg_fd();
1102
1103                 if (!FD_ISSET(fd, &w_fds))
1104                         continue;
1105
1106                 n = len - total;
1107                 if (bwlimit_writemax && n > bwlimit_writemax)
1108                         n = bwlimit_writemax;
1109                 cnt = write(fd, buf + total, n);
1110
1111                 if (cnt <= 0) {
1112                         if (cnt < 0) {
1113                                 if (errno == EINTR)
1114                                         continue;
1115                                 if (errno == EWOULDBLOCK || errno == EAGAIN) {
1116                                         msleep(1);
1117                                         continue;
1118                                 }
1119                         }
1120
1121                         /* Don't try to write errors back across the stream. */
1122                         if (fd == sock_f_out)
1123                                 close_multiplexing_out();
1124                         rsyserr(FERROR, errno,
1125                                 "writefd_unbuffered failed to write %ld bytes: phase \"%s\" [%s]",
1126                                 (long)len, io_write_phase, who_am_i());
1127                         /* If the other side is sending us error messages, try
1128                          * to grab any messages they sent before they died. */
1129                         while (fd == sock_f_out && io_multiplexing_in) {
1130                                 set_io_timeout(30);
1131                                 ignore_timeout = 0;
1132                                 readfd_unbuffered(sock_f_in, io_filesfrom_buf,
1133                                                   sizeof io_filesfrom_buf);
1134                         }
1135                         exit_cleanup(RERR_STREAMIO);
1136                 }
1137
1138                 total += cnt;
1139                 defer_forwarding_messages = 1;
1140
1141                 if (fd == sock_f_out) {
1142                         if (io_timeout || am_generator)
1143                                 last_io_out = time(NULL);
1144                         sleep_for_bwlimit(cnt);
1145                 }
1146         }
1147
1148         defer_forwarding_messages = defer_save;
1149         no_flush--;
1150 }
1151
1152 static void msg2sndr_flush(void)
1153 {
1154         if (defer_forwarding_messages)
1155                 return;
1156
1157         while (msg2sndr.head && io_multiplexing_out) {
1158                 struct msg_list_item *m = msg2sndr.head;
1159                 if (!(msg2sndr.head = m->next))
1160                         msg2sndr.tail = NULL;
1161                 stats.total_written += m->len;
1162                 defer_forwarding_messages = 1;
1163                 writefd_unbuffered(sock_f_out, m->buf, m->len);
1164                 defer_forwarding_messages = 0;
1165                 free(m);
1166         }
1167 }
1168
1169 /**
1170  * Write an message to a multiplexed stream. If this fails then rsync
1171  * exits.
1172  **/
1173 static void mplex_write(enum msgcode code, char *buf, size_t len)
1174 {
1175         char buffer[1024];
1176         size_t n = len;
1177
1178         SIVAL(buffer, 0, ((MPLEX_BASE + (int)code)<<24) + len);
1179
1180         if (n > sizeof buffer - 4)
1181                 n = 0;
1182         else
1183                 memcpy(buffer + 4, buf, n);
1184
1185         writefd_unbuffered(sock_f_out, buffer, n+4);
1186
1187         len -= n;
1188         buf += n;
1189
1190         if (len) {
1191                 defer_forwarding_messages = 1;
1192                 writefd_unbuffered(sock_f_out, buf, len);
1193                 defer_forwarding_messages = 0;
1194                 msg2sndr_flush();
1195         }
1196 }
1197
1198 void io_flush(int flush_it_all)
1199 {
1200         msg2genr_flush(flush_it_all);
1201         msg2sndr_flush();
1202
1203         if (!iobuf_out_cnt || no_flush)
1204                 return;
1205
1206         if (io_multiplexing_out)
1207                 mplex_write(MSG_DATA, iobuf_out, iobuf_out_cnt);
1208         else
1209                 writefd_unbuffered(sock_f_out, iobuf_out, iobuf_out_cnt);
1210         iobuf_out_cnt = 0;
1211 }
1212
1213 static void writefd(int fd,char *buf,size_t len)
1214 {
1215         if (fd == msg_fd_out) {
1216                 rprintf(FERROR, "Internal error: wrong write used in receiver.\n");
1217                 exit_cleanup(RERR_PROTOCOL);
1218         }
1219
1220         if (fd == sock_f_out)
1221                 stats.total_written += len;
1222
1223         if (fd == write_batch_monitor_out) {
1224                 if ((size_t)write(batch_fd, buf, len) != len)
1225                         exit_cleanup(RERR_FILEIO);
1226         }
1227
1228         if (!iobuf_out || fd != sock_f_out) {
1229                 writefd_unbuffered(fd, buf, len);
1230                 return;
1231         }
1232
1233         while (len) {
1234                 int n = MIN((int)len, IO_BUFFER_SIZE - iobuf_out_cnt);
1235                 if (n > 0) {
1236                         memcpy(iobuf_out+iobuf_out_cnt, buf, n);
1237                         buf += n;
1238                         len -= n;
1239                         iobuf_out_cnt += n;
1240                 }
1241
1242                 if (iobuf_out_cnt == IO_BUFFER_SIZE)
1243                         io_flush(NORMAL_FLUSH);
1244         }
1245 }
1246
1247 void write_shortint(int f, int x)
1248 {
1249         uchar b[2];
1250         b[0] = x;
1251         b[1] = x >> 8;
1252         writefd(f, (char *)b, 2);
1253 }
1254
1255 void write_int(int f,int32 x)
1256 {
1257         char b[4];
1258         SIVAL(b,0,x);
1259         writefd(f,b,4);
1260 }
1261
1262 void write_int_named(int f, int32 x, const char *phase)
1263 {
1264         io_write_phase = phase;
1265         write_int(f, x);
1266         io_write_phase = phase_unknown;
1267 }
1268
1269 /*
1270  * Note: int64 may actually be a 32-bit type if ./configure couldn't find any
1271  * 64-bit types on this platform.
1272  */
1273 void write_longint(int f, int64 x)
1274 {
1275         char b[8];
1276
1277         if (x <= 0x7FFFFFFF) {
1278                 write_int(f, (int)x);
1279                 return;
1280         }
1281
1282 #if SIZEOF_INT64 < 8
1283         rprintf(FERROR, "Integer overflow: attempted 64-bit offset\n");
1284         exit_cleanup(RERR_UNSUPPORTED);
1285 #else
1286         write_int(f, (int32)0xFFFFFFFF);
1287         SIVAL(b,0,(x&0xFFFFFFFF));
1288         SIVAL(b,4,((x>>32)&0xFFFFFFFF));
1289
1290         writefd(f,b,8);
1291 #endif
1292 }
1293
1294 void write_buf(int f,char *buf,size_t len)
1295 {
1296         writefd(f,buf,len);
1297 }
1298
1299 /** Write a string to the connection */
1300 void write_sbuf(int f, char *buf)
1301 {
1302         writefd(f, buf, strlen(buf));
1303 }
1304
1305 void write_byte(int f, uchar c)
1306 {
1307         writefd(f, (char *)&c, 1);
1308 }
1309
1310 void write_vstring(int f, char *str, int len)
1311 {
1312         uchar lenbuf[3], *lb = lenbuf;
1313
1314         if (len > 0x7F) {
1315                 if (len > 0x7FFF) {
1316                         rprintf(FERROR,
1317                                 "attempting to send over-long vstring (%d > %d)\n",
1318                                 len, 0x7FFF);
1319                         exit_cleanup(RERR_PROTOCOL);
1320                 }
1321                 *lb++ = len / 0x100 + 0x80;
1322         }
1323         *lb = len;
1324
1325         writefd(f, (char*)lenbuf, lb - lenbuf + 1);
1326         if (len)
1327                 writefd(f, str, len);
1328 }
1329
1330 /**
1331  * Read a line of up to @p maxlen characters into @p buf (not counting
1332  * the trailing null).  Strips the (required) trailing newline and all
1333  * carriage returns.
1334  *
1335  * @return 1 for success; 0 for I/O error or truncation.
1336  **/
1337 int read_line(int f, char *buf, size_t maxlen)
1338 {
1339         while (maxlen) {
1340                 buf[0] = 0;
1341                 read_buf(f, buf, 1);
1342                 if (buf[0] == 0)
1343                         return 0;
1344                 if (buf[0] == '\n')
1345                         break;
1346                 if (buf[0] != '\r') {
1347                         buf++;
1348                         maxlen--;
1349                 }
1350         }
1351         *buf = '\0';
1352         return maxlen > 0;
1353 }
1354
1355 void io_printf(int fd, const char *format, ...)
1356 {
1357         va_list ap;
1358         char buf[BIGPATHBUFLEN];
1359         int len;
1360
1361         va_start(ap, format);
1362         len = vsnprintf(buf, sizeof buf, format, ap);
1363         va_end(ap);
1364
1365         if (len < 0)
1366                 exit_cleanup(RERR_STREAMIO);
1367
1368         if (len > (int)sizeof buf) {
1369                 rprintf(FERROR, "io_printf() was too long for the buffer.\n");
1370                 exit_cleanup(RERR_STREAMIO);
1371         }
1372
1373         write_sbuf(fd, buf);
1374 }
1375
1376 /** Setup for multiplexing a MSG_* stream with the data stream. */
1377 void io_start_multiplex_out(void)
1378 {
1379         io_flush(NORMAL_FLUSH);
1380         io_start_buffering_out();
1381         io_multiplexing_out = 1;
1382 }
1383
1384 /** Setup for multiplexing a MSG_* stream with the data stream. */
1385 void io_start_multiplex_in(void)
1386 {
1387         io_flush(NORMAL_FLUSH);
1388         io_start_buffering_in();
1389         io_multiplexing_in = 1;
1390 }
1391
1392 /** Write an message to the multiplexed data stream. */
1393 int io_multiplex_write(enum msgcode code, char *buf, size_t len)
1394 {
1395         if (!io_multiplexing_out)
1396                 return 0;
1397
1398         io_flush(NORMAL_FLUSH);
1399         stats.total_written += (len+4);
1400         mplex_write(code, buf, len);
1401         return 1;
1402 }
1403
1404 void close_multiplexing_in(void)
1405 {
1406         io_multiplexing_in = 0;
1407 }
1408
1409 /** Stop output multiplexing. */
1410 void close_multiplexing_out(void)
1411 {
1412         io_multiplexing_out = 0;
1413 }
1414
1415 void start_write_batch(int fd)
1416 {
1417         write_stream_flags(batch_fd);
1418
1419         /* Some communication has already taken place, but we don't
1420          * enable batch writing until here so that we can write a
1421          * canonical record of the communication even though the
1422          * actual communication so far depends on whether a daemon
1423          * is involved. */
1424         write_int(batch_fd, protocol_version);
1425         write_int(batch_fd, checksum_seed);
1426
1427         if (am_sender)
1428                 write_batch_monitor_out = fd;
1429         else
1430                 write_batch_monitor_in = fd;
1431 }
1432
1433 void stop_write_batch(void)
1434 {
1435         write_batch_monitor_out = -1;
1436         write_batch_monitor_in = -1;
1437 }