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 verbose;
  45 extern int io_timeout;
  46 extern int allowed_lull;
  47 extern int am_server;
  48 extern int am_daemon;
  49 extern int am_sender;
  50 extern int am_generator;
  51 extern int eol_nulls;
  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 select_timeout = SELECT_TIMEOUT;
  63 int ignore_timeout = 0;
  64 int batch_fd = -1;
  65 int batch_gen_fd = -1;
  66
  67 /**
  68  * The connection might be dropped at some point; perhaps because the
  69  * remote instance crashed.  Just giving the offset on the stream is
  70  * not very helpful.  So instead we try to make io_phase_name point to
  71  * something useful.
  72  *
  73  * For buffered/multiplexed I/O these names will be somewhat
  74  * approximate; perhaps for ease of support we would rather make the
  75  * buffer always flush when a single application-level I/O finishes.
  76  *
  77  * @todo Perhaps we want some simple stack functionality, but there's
  78  * no need to overdo it.
  79  **/
  80 const char *io_write_phase = phase_unknown;
  81 const char *io_read_phase = phase_unknown;
  82
  83 /* Ignore an EOF error if non-zero. See whine_about_eof(). */
  84 int kluge_around_eof = 0;
  85
  86 int msg_fd_in = -1;
  87 int msg_fd_out = -1;
  88 int sock_f_in = -1;
  89 int sock_f_out = -1;
  90
  91 static int io_multiplexing_out;
  92 static int io_multiplexing_in;
  93 static time_t last_io;
  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 size_t contiguous_write_len = 0;
 106
 107 static void read_loop(int fd, char *buf, size_t len);
 108
 109 struct flist_ndx_item {
 110         struct flist_ndx_item *next;
 111         int ndx;
 112 };
 113
 114 struct flist_ndx_list {
 115         struct flist_ndx_item *head, *tail;
 116 };
 117
 118 static struct flist_ndx_list redo_list, hlink_list;
 119
 120 struct msg_list {
 121         struct msg_list *next;
 122         char *buf;
 123         int len;
 124 };
 125
 126 static struct msg_list *msg_list_head;
 127 static struct msg_list *msg_list_tail;
 128
 129 static void flist_ndx_push(struct flist_ndx_list *lp, int ndx)
 130 {
 131         struct flist_ndx_item *item;
 132
 133         if (!(item = new(struct flist_ndx_item)))
 134                 out_of_memory("flist_ndx_push");
 135         item->next = NULL;
 136         item->ndx = ndx;
 137         if (lp->tail)
 138                 lp->tail->next = item;
 139         else
 140                 lp->head = item;
 141         lp->tail = item;
 142 }
 143
 144 static int flist_ndx_pop(struct flist_ndx_list *lp)
 145 {
 146         struct flist_ndx_item *next;
 147         int ndx;
 148
 149         if (!lp->head)
 150                 return -1;
 151
 152         ndx = lp->head->ndx;
 153         next = lp->head->next;
 154         free(lp->head);
 155         lp->head = next;
 156         if (!next)
 157                 lp->tail = NULL;
 158
 159         return ndx;
 160 }
 161
 162 static void check_timeout(void)
 163 {
 164         time_t t;
 165
 166         if (!io_timeout || ignore_timeout)
 167                 return;
 168
 169         if (!last_io) {
 170                 last_io = time(NULL);
 171                 return;
 172         }
 173
 174         t = time(NULL);
 175
 176         if (t - last_io >= io_timeout) {
 177                 if (!am_server && !am_daemon) {
 178                         rprintf(FERROR, "io timeout after %d seconds -- exiting\n",
 179                                 (int)(t-last_io));
 180                 }
 181                 exit_cleanup(RERR_TIMEOUT);
 182         }
 183 }
 184
 185 /* Note the fds used for the main socket (which might really be a pipe
 186  * for a local transfer, but we can ignore that). */
 187 void io_set_sock_fds(int f_in, int f_out)
 188 {
 189         sock_f_in = f_in;
 190         sock_f_out = f_out;
 191 }
 192
 193 /* Setup the fd used to receive MSG_* messages.  Only needed during the
 194  * early stages of being a local sender (up through the sending of the
 195  * file list) or when we're the generator (to fetch the messages from
 196  * the receiver). */
 197 void set_msg_fd_in(int fd)
 198 {
 199         msg_fd_in = fd;
 200 }
 201
 202 /* Setup the fd used to send our MSG_* messages.  Only needed when
 203  * we're the receiver (to send our messages to the generator). */
 204 void set_msg_fd_out(int fd)
 205 {
 206         msg_fd_out = fd;
 207         set_nonblocking(msg_fd_out);
 208 }
 209
 210 /* Add a message to the pending MSG_* list. */
 211 static void msg_list_add(int code, char *buf, int len)
 212 {
 213         struct msg_list *ml;
 214
 215         if (!(ml = new(struct msg_list)))
 216                 out_of_memory("msg_list_add");
 217         ml->next = NULL;
 218         if (!(ml->buf = new_array(char, len+4)))
 219                 out_of_memory("msg_list_add");
 220         SIVAL(ml->buf, 0, ((code+MPLEX_BASE)<<24) | len);
 221         memcpy(ml->buf+4, buf, len);
 222         ml->len = len+4;
 223         if (msg_list_tail)
 224                 msg_list_tail->next = ml;
 225         else
 226                 msg_list_head = ml;
 227         msg_list_tail = ml;
 228 }
 229
 230 void send_msg(enum msgcode code, char *buf, int len)
 231 {
 232         if (msg_fd_out < 0) {
 233                 io_multiplex_write(code, buf, len);
 234                 return;
 235         }
 236         msg_list_add(code, buf, len);
 237         msg_list_push(NORMAL_FLUSH);
 238 }
 239
 240 /* Read a message from the MSG_* fd and handle it.  This is called either
 241  * during the early stages of being a local sender (up through the sending
 242  * of the file list) or when we're the generator (to fetch the messages
 243  * from the receiver). */
 244 static void read_msg_fd(void)
 245 {
 246         char buf[2048];
 247         size_t n;
 248         int fd = msg_fd_in;
 249         int tag, len;
 250
 251         /* Temporarily disable msg_fd_in.  This is needed to avoid looping back
 252          * to this routine from writefd_unbuffered(). */
 253         msg_fd_in = -1;
 254
 255         read_loop(fd, buf, 4);
 256         tag = IVAL(buf, 0);
 257
 258         len = tag & 0xFFFFFF;
 259         tag = (tag >> 24) - MPLEX_BASE;
 260
 261         switch (tag) {
 262         case MSG_DONE:
 263                 if (len != 0 || !am_generator) {
 264                         rprintf(FERROR, "invalid message %d:%d\n", tag, len);
 265                         exit_cleanup(RERR_STREAMIO);
 266                 }
 267                 flist_ndx_push(&redo_list, -1);
 268                 break;
 269         case MSG_REDO:
 270                 if (len != 4 || !am_generator) {
 271                         rprintf(FERROR, "invalid message %d:%d\n", tag, len);
 272                         exit_cleanup(RERR_STREAMIO);
 273                 }
 274                 read_loop(fd, buf, 4);
 275                 flist_ndx_push(&redo_list, IVAL(buf,0));
 276                 break;
 277         case MSG_DELETED:
 278                 if (len >= (int)sizeof buf || !am_generator) {
 279                         rprintf(FERROR, "invalid message %d:%d\n", tag, len);
 280                         exit_cleanup(RERR_STREAMIO);
 281                 }
 282                 read_loop(fd, buf, len);
 283                 io_multiplex_write(MSG_DELETED, buf, len);
 284                 break;
 285         case MSG_SUCCESS:
 286                 if (len != 4 || !am_generator) {
 287                         rprintf(FERROR, "invalid message %d:%d\n", tag, len);
 288                         exit_cleanup(RERR_STREAMIO);
 289                 }
 290                 read_loop(fd, buf, len);
 291                 if (remove_sent_files)
 292                         io_multiplex_write(MSG_SUCCESS, buf, len);
 293                 if (preserve_hard_links)
 294                         flist_ndx_push(&hlink_list, IVAL(buf,0));
 295                 break;
 296         case MSG_INFO:
 297         case MSG_ERROR:
 298         case MSG_LOG:
 299                 while (len) {
 300                         n = len;
 301                         if (n >= sizeof buf)
 302                                 n = sizeof buf - 1;
 303                         read_loop(fd, buf, n);
 304                         rwrite((enum logcode)tag, buf, n);
 305                         len -= n;
 306                 }
 307                 break;
 308         default:
 309                 rprintf(FERROR, "unknown message %d:%d\n", tag, len);
 310                 exit_cleanup(RERR_STREAMIO);
 311         }
 312
 313         msg_fd_in = fd;
 314 }
 315
 316 /* Try to push messages off the list onto the wire.  If we leave with more
 317  * to do, return 0.  On error, return -1.  If everything flushed, return 1.
 318  * This is only active in the receiver. */
 319 int msg_list_push(int flush_it_all)
 320 {
 321         static int written = 0;
 322         struct timeval tv;
 323         fd_set fds;
 324
 325         if (msg_fd_out < 0)
 326                 return -1;
 327
 328         while (msg_list_head) {
 329                 struct msg_list *ml = msg_list_head;
 330                 int n = write(msg_fd_out, ml->buf + written, ml->len - written);
 331                 if (n < 0) {
 332                         if (errno == EINTR)
 333                                 continue;
 334                         if (errno != EWOULDBLOCK && errno != EAGAIN)
 335                                 return -1;
 336                         if (!flush_it_all)
 337                                 return 0;
 338                         FD_ZERO(&fds);
 339                         FD_SET(msg_fd_out, &fds);
 340                         tv.tv_sec = select_timeout;
 341                         tv.tv_usec = 0;
 342                         if (!select(msg_fd_out+1, NULL, &fds, NULL, &tv))
 343                                 check_timeout();
 344                 } else if ((written += n) == ml->len) {
 345                         free(ml->buf);
 346                         msg_list_head = ml->next;
 347                         if (!msg_list_head)
 348                                 msg_list_tail = NULL;
 349                         free(ml);
 350                         written = 0;
 351                 }
 352         }
 353         return 1;
 354 }
 355
 356 int get_redo_num(int itemizing, enum logcode code)
 357 {
 358         while (1) {
 359                 if (hlink_list.head)
 360                         check_for_finished_hlinks(itemizing, code);
 361                 if (redo_list.head)
 362                         break;
 363                 read_msg_fd();
 364         }
 365
 366         return flist_ndx_pop(&redo_list);
 367 }
 368
 369 int get_hlink_num(void)
 370 {
 371         return flist_ndx_pop(&hlink_list);
 372 }
 373
 374 /**
 375  * When we're the receiver and we have a local --files-from list of names
 376  * that needs to be sent over the socket to the sender, we have to do two
 377  * things at the same time: send the sender a list of what files we're
 378  * processing and read the incoming file+info list from the sender.  We do
 379  * this by augmenting the read_timeout() function to copy this data.  It
 380  * uses the io_filesfrom_buf to read a block of data from f_in (when it is
 381  * ready, since it might be a pipe) and then blast it out f_out (when it
 382  * is ready to receive more data).
 383  */
 384 void io_set_filesfrom_fds(int f_in, int f_out)
 385 {
 386         io_filesfrom_f_in = f_in;
 387         io_filesfrom_f_out = f_out;
 388         io_filesfrom_bp = io_filesfrom_buf;
 389         io_filesfrom_lastchar = '\0';
 390         io_filesfrom_buflen = 0;
 391 }
 392
 393 /* It's almost always an error to get an EOF when we're trying to read from the
 394  * network, because the protocol is (for the most part) self-terminating.
 395  *
 396  * There is one case for the receiver when it is at the end of the transfer
 397  * (hanging around reading any keep-alive packets that might come its way): if
 398  * the sender dies before the generator's kill-signal comes through, we can end
 399  * up here needing to loop until the kill-signal arrives.  In this situation,
 400  * kluge_around_eof will be < 0.
 401  *
 402  * There is another case for older protocol versions (< 24) where the module
 403  * listing was not terminated, so we must ignore an EOF error in that case and
 404  * exit.  In this situation, kluge_around_eof will be > 0. */
 405 static void whine_about_eof(int fd)
 406 {
 407         if (kluge_around_eof && fd == sock_f_in) {
 408                 int i;
 409                 if (kluge_around_eof > 0)
 410                         exit_cleanup(0);
 411                 /* If we're still here after 10 seconds, exit with an error. */
 412                 for (i = 10*1000/20; i--; )
 413                         msleep(20);
 414         }
 415
 416         rprintf(FERROR, RSYNC_NAME ": connection unexpectedly closed "
 417                 "(%.0f bytes received so far) [%s]\n",
 418                 (double)stats.total_read, who_am_i());
 419
 420         exit_cleanup(RERR_STREAMIO);
 421 }
 422
 423
 424 /**
 425  * Read from a socket with I/O timeout. return the number of bytes
 426  * read. If no bytes can be read then exit, never return a number <= 0.
 427  *
 428  * TODO: If the remote shell connection fails, then current versions
 429  * actually report an "unexpected EOF" error here.  Since it's a
 430  * fairly common mistake to try to use rsh when ssh is required, we
 431  * should trap that: if we fail to read any data at all, we should
 432  * give a better explanation.  We can tell whether the connection has
 433  * started by looking e.g. at whether the remote version is known yet.
 434  */
 435 static int read_timeout(int fd, char *buf, size_t len)
 436 {
 437         int n, ret = 0;
 438
 439         io_flush(NORMAL_FLUSH);
 440
 441         while (ret == 0) {
 442                 /* until we manage to read *something* */
 443                 fd_set r_fds, w_fds;
 444                 struct timeval tv;
 445                 int maxfd = fd;
 446                 int count;
 447
 448                 FD_ZERO(&r_fds);
 449                 FD_ZERO(&w_fds);
 450                 FD_SET(fd, &r_fds);
 451                 if (msg_list_head) {
 452                         FD_SET(msg_fd_out, &w_fds);
 453                         if (msg_fd_out > maxfd)
 454                                 maxfd = msg_fd_out;
 455                 }
 456                 if (io_filesfrom_f_out >= 0) {
 457                         int new_fd;
 458                         if (io_filesfrom_buflen == 0) {
 459                                 if (io_filesfrom_f_in >= 0) {
 460                                         FD_SET(io_filesfrom_f_in, &r_fds);
 461                                         new_fd = io_filesfrom_f_in;
 462                                 } else {
 463                                         io_filesfrom_f_out = -1;
 464                                         new_fd = -1;
 465                                 }
 466                         } else {
 467                                 FD_SET(io_filesfrom_f_out, &w_fds);
 468                                 new_fd = io_filesfrom_f_out;
 469                         }
 470                         if (new_fd > maxfd)
 471                                 maxfd = new_fd;
 472                 }
 473
 474                 tv.tv_sec = select_timeout;
 475                 tv.tv_usec = 0;
 476
 477                 errno = 0;
 478
 479                 count = select(maxfd + 1, &r_fds, &w_fds, NULL, &tv);
 480
 481                 if (count <= 0) {
 482                         if (errno == EBADF)
 483                                 exit_cleanup(RERR_SOCKETIO);
 484                         check_timeout();
 485                         continue;
 486                 }
 487
 488                 if (msg_list_head && FD_ISSET(msg_fd_out, &w_fds))
 489                         msg_list_push(NORMAL_FLUSH);
 490
 491                 if (io_filesfrom_f_out >= 0) {
 492                         if (io_filesfrom_buflen) {
 493                                 if (FD_ISSET(io_filesfrom_f_out, &w_fds)) {
 494                                         int l = write(io_filesfrom_f_out,
 495                                                       io_filesfrom_bp,
 496                                                       io_filesfrom_buflen);
 497                                         if (l > 0) {
 498                                                 if (!(io_filesfrom_buflen -= l))
 499                                                         io_filesfrom_bp = io_filesfrom_buf;
 500                                                 else
 501                                                         io_filesfrom_bp += l;
 502                                         } else {
 503                                                 /* XXX should we complain? */
 504                                                 io_filesfrom_f_out = -1;
 505                                         }
 506                                 }
 507                         } else if (io_filesfrom_f_in >= 0) {
 508                                 if (FD_ISSET(io_filesfrom_f_in, &r_fds)) {
 509                                         int l = read(io_filesfrom_f_in,
 510                                                      io_filesfrom_buf,
 511                                                      sizeof io_filesfrom_buf);
 512                                         if (l <= 0) {
 513                                                 /* Send end-of-file marker */
 514                                                 io_filesfrom_buf[0] = '\0';
 515                                                 io_filesfrom_buf[1] = '\0';
 516                                                 io_filesfrom_buflen = io_filesfrom_lastchar? 2 : 1;
 517                                                 io_filesfrom_f_in = -1;
 518                                         } else {
 519                                                 if (!eol_nulls) {
 520                                                         char *s = io_filesfrom_buf + l;
 521                                                         /* Transform CR and/or LF into '\0' */
 522                                                         while (s-- > io_filesfrom_buf) {
 523                                                                 if (*s == '\n' || *s == '\r')
 524                                                                         *s = '\0';
 525                                                         }
 526                                                 }
 527                                                 if (!io_filesfrom_lastchar) {
 528                                                         /* Last buf ended with a '\0', so don't
 529                                                          * let this buf start with one. */
 530                                                         while (l && !*io_filesfrom_bp)
 531                                                                 io_filesfrom_bp++, l--;
 532                                                 }
 533                                                 if (!l)
 534                                                         io_filesfrom_bp = io_filesfrom_buf;
 535                                                 else {
 536                                                         char *f = io_filesfrom_bp;
 537                                                         char *t = f;
 538                                                         char *eob = f + l;
 539                                                         /* Eliminate any multi-'\0' runs. */
 540                                                         while (f != eob) {
 541                                                                 if (!(*t++ = *f++)) {
 542                                                                         while (f != eob && !*f)
 543                                                                                 f++, l--;
 544                                                                 }
 545                                                         }
 546                                                         io_filesfrom_lastchar = f[-1];
 547                                                 }
 548                                                 io_filesfrom_buflen = l;
 549                                         }
 550                                 }
 551                         }
 552                 }
 553
 554                 if (!FD_ISSET(fd, &r_fds))
 555                         continue;
 556
 557                 n = read(fd, buf, len);
 558
 559                 if (n <= 0) {
 560                         if (n == 0)
 561                                 whine_about_eof(fd); /* Doesn't return. */
 562                         if (errno == EINTR || errno == EWOULDBLOCK
 563                             || errno == EAGAIN)
 564                                 continue;
 565
 566                         /* Don't write errors on a dead socket. */
 567                         if (fd == sock_f_in)
 568                                 close_multiplexing_out();
 569                         rsyserr(FERROR, errno, "read error");
 570                         exit_cleanup(RERR_STREAMIO);
 571                 }
 572
 573                 buf += n;
 574                 len -= n;
 575                 ret += n;
 576
 577                 if (io_timeout && fd == sock_f_in)
 578                         last_io = time(NULL);
 579         }
 580
 581         return ret;
 582 }
 583
 584 /**
 585  * Read a line into the "fname" buffer (which must be at least MAXPATHLEN
 586  * characters long).
 587  */
 588 int read_filesfrom_line(int fd, char *fname)
 589 {
 590         char ch, *s, *eob = fname + MAXPATHLEN - 1;
 591         int cnt;
 592         int reading_remotely = filesfrom_host != NULL;
 593         int nulls = eol_nulls || reading_remotely;
 594
 595   start:
 596         s = fname;
 597         while (1) {
 598                 cnt = read(fd, &ch, 1);
 599                 if (cnt < 0 && (errno == EWOULDBLOCK
 600                   || errno == EINTR || errno == EAGAIN)) {
 601                         struct timeval tv;
 602                         fd_set fds;
 603                         FD_ZERO(&fds);
 604                         FD_SET(fd, &fds);
 605                         tv.tv_sec = select_timeout;
 606                         tv.tv_usec = 0;
 607                         if (!select(fd+1, &fds, NULL, NULL, &tv))
 608                                 check_timeout();
 609                         continue;
 610                 }
 611                 if (cnt != 1)
 612                         break;
 613                 if (nulls? !ch : (ch == '\r' || ch == '\n')) {
 614                         /* Skip empty lines if reading locally. */
 615                         if (!reading_remotely && s == fname)
 616                                 continue;
 617                         break;
 618                 }
 619                 if (s < eob)
 620                         *s++ = ch;
 621         }
 622         *s = '\0';
 623
 624         /* Dump comments. */
 625         if (*fname == '#' || *fname == ';')
 626                 goto start;
 627
 628         return s - fname;
 629 }
 630
 631
 632 static char *iobuf_out;
 633 static int iobuf_out_cnt;
 634
 635 void io_start_buffering_out(void)
 636 {
 637         if (iobuf_out)
 638                 return;
 639         if (!(iobuf_out = new_array(char, IO_BUFFER_SIZE)))
 640                 out_of_memory("io_start_buffering_out");
 641         iobuf_out_cnt = 0;
 642 }
 643
 644
 645 static char *iobuf_in;
 646 static size_t iobuf_in_siz;
 647
 648 void io_start_buffering_in(void)
 649 {
 650         if (iobuf_in)
 651                 return;
 652         iobuf_in_siz = 2 * IO_BUFFER_SIZE;
 653         if (!(iobuf_in = new_array(char, iobuf_in_siz)))
 654                 out_of_memory("io_start_buffering_in");
 655 }
 656
 657
 658 void io_end_buffering(void)
 659 {
 660         io_flush(NORMAL_FLUSH);
 661         if (!io_multiplexing_out) {
 662                 free(iobuf_out);
 663                 iobuf_out = NULL;
 664         }
 665 }
 666
 667
 668 void maybe_send_keepalive(void)
 669 {
 670         if (time(NULL) - last_io >= allowed_lull) {
 671                 if (!iobuf_out || !iobuf_out_cnt) {
 672                         if (protocol_version < 29)
 673                                 return; /* there's nothing we can do */
 674                         write_int(sock_f_out, the_file_list->count);
 675                         write_shortint(sock_f_out, ITEM_IS_NEW);
 676                 }
 677                 if (iobuf_out)
 678                         io_flush(NORMAL_FLUSH);
 679         }
 680 }
 681
 682
 683 /**
 684  * Continue trying to read len bytes - don't return until len has been
 685  * read.
 686  **/
 687 static void read_loop(int fd, char *buf, size_t len)
 688 {
 689         while (len) {
 690                 int n = read_timeout(fd, buf, len);
 691
 692                 buf += n;
 693                 len -= n;
 694         }
 695 }
 696
 697
 698 /**
 699  * Read from the file descriptor handling multiplexing - return number
 700  * of bytes read.
 701  *
 702  * Never returns <= 0.
 703  */
 704 static int readfd_unbuffered(int fd, char *buf, size_t len)
 705 {
 706         static size_t remaining;
 707         static size_t iobuf_in_ndx;
 708         int tag, ret = 0;
 709         char line[MAXPATHLEN+1];
 710
 711         if (!iobuf_in || fd != sock_f_in)
 712                 return read_timeout(fd, buf, len);
 713
 714         if (!io_multiplexing_in && remaining == 0) {
 715                 remaining = read_timeout(fd, iobuf_in, iobuf_in_siz);
 716                 iobuf_in_ndx = 0;
 717         }
 718
 719         while (ret == 0) {
 720                 if (remaining) {
 721                         len = MIN(len, remaining);
 722                         memcpy(buf, iobuf_in + iobuf_in_ndx, len);
 723                         iobuf_in_ndx += len;
 724                         remaining -= len;
 725                         ret = len;
 726                         break;
 727                 }
 728
 729                 read_loop(fd, line, 4);
 730                 tag = IVAL(line, 0);
 731
 732                 remaining = tag & 0xFFFFFF;
 733                 tag = (tag >> 24) - MPLEX_BASE;
 734
 735                 switch (tag) {
 736                 case MSG_DATA:
 737                         if (remaining > iobuf_in_siz) {
 738                                 if (!(iobuf_in = realloc_array(iobuf_in, char,
 739                                                                remaining)))
 740                                         out_of_memory("readfd_unbuffered");
 741                                 iobuf_in_siz = remaining;
 742                         }
 743                         read_loop(fd, iobuf_in, remaining);
 744                         iobuf_in_ndx = 0;
 745                         break;
 746                 case MSG_DELETED:
 747                         if (remaining >= sizeof line) {
 748                                 rprintf(FERROR, "invalid multi-message %d:%ld\n",
 749                                         tag, (long)remaining);
 750                                 exit_cleanup(RERR_STREAMIO);
 751                         }
 752                         read_loop(fd, line, remaining);
 753                         line[remaining] = '\0';
 754                         /* A directory name was sent with the trailing null */
 755                         if (remaining > 0 && !line[remaining-1])
 756                                 log_delete(line, S_IFDIR);
 757                         else
 758                                 log_delete(line, S_IFREG);
 759                         remaining = 0;
 760                         break;
 761                 case MSG_SUCCESS:
 762                         if (remaining != 4) {
 763                                 rprintf(FERROR, "invalid multi-message %d:%ld [%s]\n",
 764                                         tag, (long)remaining, who_am_i());
 765                                 exit_cleanup(RERR_STREAMIO);
 766                         }
 767                         read_loop(fd, line, remaining);
 768                         successful_send(IVAL(line, 0));
 769                         remaining = 0;
 770                         break;
 771                 case MSG_INFO:
 772                 case MSG_ERROR:
 773                         if (remaining >= sizeof line) {
 774                                 rprintf(FERROR,
 775                                         "multiplexing overflow %d:%ld [%s]\n",
 776                                         tag, (long)remaining, who_am_i());
 777                                 exit_cleanup(RERR_STREAMIO);
 778                         }
 779                         read_loop(fd, line, remaining);
 780                         rwrite((enum logcode)tag, line, remaining);
 781                         remaining = 0;
 782                         break;
 783                 default:
 784                         rprintf(FERROR, "unexpected tag %d [%s]\n",
 785                                 tag, who_am_i());
 786                         exit_cleanup(RERR_STREAMIO);
 787                 }
 788         }
 789
 790         if (remaining == 0)
 791                 io_flush(NORMAL_FLUSH);
 792
 793         return ret;
 794 }
 795
 796
 797
 798 /**
 799  * Do a buffered read from @p fd.  Don't return until all @p n bytes
 800  * have been read.  If all @p n can't be read then exit with an
 801  * error.
 802  **/
 803 static void readfd(int fd, char *buffer, size_t N)
 804 {
 805         int  ret;
 806         size_t total = 0;
 807
 808         while (total < N) {
 809                 ret = readfd_unbuffered(fd, buffer + total, N-total);
 810                 total += ret;
 811         }
 812
 813         if (fd == write_batch_monitor_in) {
 814                 if ((size_t)write(batch_fd, buffer, total) != total)
 815                         exit_cleanup(RERR_FILEIO);
 816         }
 817
 818         if (fd == sock_f_in)
 819                 stats.total_read += total;
 820 }
 821
 822
 823 int read_shortint(int f)
 824 {
 825         uchar b[2];
 826         readfd(f, (char *)b, 2);
 827         return (b[1] << 8) + b[0];
 828 }
 829
 830
 831 int32 read_int(int f)
 832 {
 833         char b[4];
 834         int32 ret;
 835
 836         readfd(f,b,4);
 837         ret = IVAL(b,0);
 838         if (ret == (int32)0xffffffff)
 839                 return -1;
 840         return ret;
 841 }
 842
 843 int64 read_longint(int f)
 844 {
 845         int64 ret;
 846         char b[8];
 847         ret = read_int(f);
 848
 849         if ((int32)ret != (int32)0xffffffff)
 850                 return ret;
 851
 852 #if SIZEOF_INT64 < 8
 853         rprintf(FERROR, "Integer overflow: attempted 64-bit offset\n");
 854         exit_cleanup(RERR_UNSUPPORTED);
 855 #else
 856         readfd(f,b,8);
 857         ret = IVAL(b,0) | (((int64)IVAL(b,4))<<32);
 858 #endif
 859
 860         return ret;
 861 }
 862
 863 void read_buf(int f,char *buf,size_t len)
 864 {
 865         readfd(f,buf,len);
 866 }
 867
 868 void read_sbuf(int f,char *buf,size_t len)
 869 {
 870         readfd(f, buf, len);
 871         buf[len] = '\0';
 872 }
 873
 874 uchar read_byte(int f)
 875 {
 876         uchar c;
 877         readfd(f, (char *)&c, 1);
 878         return c;
 879 }
 880
 881 int read_vstring(int f, char *buf, int bufsize)
 882 {
 883         int len = read_byte(f);
 884
 885         if (len & 0x80)
 886                 len = (len & ~0x80) * 0x100 + read_byte(f);
 887
 888         if (len >= bufsize) {
 889                 rprintf(FERROR, "over-long vstring received (%d > %d)\n",
 890                         len, bufsize - 1);
 891                 exit_cleanup(RERR_PROTOCOL);
 892         }
 893
 894         if (len)
 895                 readfd(f, buf, len);
 896         buf[len] = '\0';
 897         return len;
 898 }
 899
 900 /* Populate a sum_struct with values from the socket.  This is
 901  * called by both the sender and the receiver. */
 902 void read_sum_head(int f, struct sum_struct *sum)
 903 {
 904         sum->count = read_int(f);
 905         sum->blength = read_int(f);
 906         if (sum->blength < 0 || sum->blength > MAX_BLOCK_SIZE) {
 907                 rprintf(FERROR, "Invalid block length %ld [%s]\n",
 908                         (long)sum->blength, who_am_i());
 909                 exit_cleanup(RERR_PROTOCOL);
 910         }
 911         sum->s2length = protocol_version < 27 ? csum_length : (int)read_int(f);
 912         if (sum->s2length < 0 || sum->s2length > MD4_SUM_LENGTH) {
 913                 rprintf(FERROR, "Invalid checksum length %d [%s]\n",
 914                         sum->s2length, who_am_i());
 915                 exit_cleanup(RERR_PROTOCOL);
 916         }
 917         sum->remainder = read_int(f);
 918         if (sum->remainder < 0 || sum->remainder > sum->blength) {
 919                 rprintf(FERROR, "Invalid remainder length %ld [%s]\n",
 920                         (long)sum->remainder, who_am_i());
 921                 exit_cleanup(RERR_PROTOCOL);
 922         }
 923 }
 924
 925 /* Send the values from a sum_struct over the socket.  Set sum to
 926  * NULL if there are no checksums to send.  This is called by both
 927  * the generator and the sender. */
 928 void write_sum_head(int f, struct sum_struct *sum)
 929 {
 930         static struct sum_struct null_sum;
 931
 932         if (sum == NULL)
 933                 sum = &null_sum;
 934
 935         write_int(f, sum->count);
 936         write_int(f, sum->blength);
 937         if (protocol_version >= 27)
 938                 write_int(f, sum->s2length);
 939         write_int(f, sum->remainder);
 940 }
 941
 942
 943 /**
 944  * Sleep after writing to limit I/O bandwidth usage.
 945  *
 946  * @todo Rather than sleeping after each write, it might be better to
 947  * use some kind of averaging.  The current algorithm seems to always
 948  * use a bit less bandwidth than specified, because it doesn't make up
 949  * for slow periods.  But arguably this is a feature.  In addition, we
 950  * ought to take the time used to write the data into account.
 951  *
 952  * During some phases of big transfers (file FOO is uptodate) this is
 953  * called with a small bytes_written every time.  As the kernel has to
 954  * round small waits up to guarantee that we actually wait at least the
 955  * requested number of microseconds, this can become grossly inaccurate.
 956  * We therefore keep track of the bytes we've written over time and only
 957  * sleep when the accumulated delay is at least 1 tenth of a second.
 958  **/
 959 static void sleep_for_bwlimit(int bytes_written)
 960 {
 961         static struct timeval prior_tv;
 962         static long total_written = 0;
 963         struct timeval tv, start_tv;
 964         long elapsed_usec, sleep_usec;
 965
 966 #define ONE_SEC 1000000L /* # of microseconds in a second */
 967
 968         if (!bwlimit)
 969                 return;
 970
 971         total_written += bytes_written;
 972
 973         gettimeofday(&start_tv, NULL);
 974         if (prior_tv.tv_sec) {
 975                 elapsed_usec = (start_tv.tv_sec - prior_tv.tv_sec) * ONE_SEC
 976                              + (start_tv.tv_usec - prior_tv.tv_usec);
 977                 total_written -= elapsed_usec * bwlimit / (ONE_SEC/1024);
 978                 if (total_written < 0)
 979                         total_written = 0;
 980         }
 981
 982         sleep_usec = total_written * (ONE_SEC/1024) / bwlimit;
 983         if (sleep_usec < ONE_SEC / 10) {
 984                 prior_tv = start_tv;
 985                 return;
 986         }
 987
 988         tv.tv_sec  = sleep_usec / ONE_SEC;
 989         tv.tv_usec = sleep_usec % ONE_SEC;
 990         select(0, NULL, NULL, NULL, &tv);
 991
 992         gettimeofday(&prior_tv, NULL);
 993         elapsed_usec = (prior_tv.tv_sec - start_tv.tv_sec) * ONE_SEC
 994                      + (prior_tv.tv_usec - start_tv.tv_usec);
 995         total_written = (sleep_usec - elapsed_usec) * bwlimit / (ONE_SEC/1024);
 996 }
 997
 998
 999 /* Write len bytes to the file descriptor fd, looping as necessary to get
1000  * the job done and also (in certain circumstnces) reading any data on
1001  * msg_fd_in to avoid deadlock.
1002  *
1003  * This function underlies the multiplexing system.  The body of the
1004  * application never calls this function directly. */
1005 static void writefd_unbuffered(int fd,char *buf,size_t len)
1006 {
1007         size_t n, total = 0;
1008         fd_set w_fds, r_fds;
1009         int maxfd, count, ret;
1010         struct timeval tv;
1011
1012         no_flush++;
1013
1014         while (total < len) {
1015                 FD_ZERO(&w_fds);
1016                 FD_SET(fd,&w_fds);
1017                 maxfd = fd;
1018
1019                 if (msg_fd_in >= 0 && len-total >= contiguous_write_len) {
1020                         FD_ZERO(&r_fds);
1021                         FD_SET(msg_fd_in,&r_fds);
1022                         if (msg_fd_in > maxfd)
1023                                 maxfd = msg_fd_in;
1024                 }
1025                 if (fd != sock_f_out && iobuf_out_cnt && no_flush == 1) {
1026                         FD_SET(sock_f_out, &w_fds);
1027                         if (sock_f_out > maxfd)
1028                                 maxfd = sock_f_out;
1029                 }
1030
1031                 tv.tv_sec = select_timeout;
1032                 tv.tv_usec = 0;
1033
1034                 errno = 0;
1035                 count = select(maxfd + 1, msg_fd_in >= 0 ? &r_fds : NULL,
1036                                &w_fds, NULL, &tv);
1037
1038                 if (count <= 0) {
1039                         if (count < 0 && errno == EBADF)
1040                                 exit_cleanup(RERR_SOCKETIO);
1041                         check_timeout();
1042                         continue;
1043                 }
1044
1045                 if (msg_fd_in >= 0 && FD_ISSET(msg_fd_in, &r_fds))
1046                         read_msg_fd();
1047
1048                 if (!FD_ISSET(fd, &w_fds)) {
1049                         if (fd != sock_f_out && iobuf_out_cnt) {
1050                                 no_flush--;
1051                                 io_flush(NORMAL_FLUSH);
1052                                 no_flush++;
1053                         }
1054                         continue;
1055                 }
1056
1057                 n = len - total;
1058                 if (bwlimit && n > bwlimit_writemax)
1059                         n = bwlimit_writemax;
1060                 ret = write(fd, buf + total, n);
1061
1062                 if (ret <= 0) {
1063                         if (ret < 0) {
1064                                 if (errno == EINTR)
1065                                         continue;
1066                                 if (errno == EWOULDBLOCK || errno == EAGAIN) {
1067                                         msleep(1);
1068                                         continue;
1069                                 }
1070                         }
1071
1072                         /* Don't try to write errors back across the stream. */
1073                         if (fd == sock_f_out)
1074                                 close_multiplexing_out();
1075                         rsyserr(FERROR, errno,
1076                                 "writefd_unbuffered failed to write %ld bytes: phase \"%s\" [%s]",
1077                                 (long)len, io_write_phase, who_am_i());
1078                         /* If the other side is sending us error messages, try
1079                          * to grab any messages they sent before they died. */
1080                         while (fd == sock_f_out && io_multiplexing_in) {
1081                                 io_timeout = select_timeout = 30;
1082                                 ignore_timeout = 0;
1083                                 readfd_unbuffered(sock_f_in, io_filesfrom_buf,
1084                                                   sizeof io_filesfrom_buf);
1085                         }
1086                         exit_cleanup(RERR_STREAMIO);
1087                 }
1088
1089                 total += ret;
1090
1091                 if (fd == sock_f_out) {
1092                         if (io_timeout)
1093                                 last_io = time(NULL);
1094                         sleep_for_bwlimit(ret);
1095                 }
1096         }
1097
1098         no_flush--;
1099 }
1100
1101
1102 /**
1103  * Write an message to a multiplexed stream. If this fails then rsync
1104  * exits.
1105  **/
1106 static void mplex_write(enum msgcode code, char *buf, size_t len)
1107 {
1108         char buffer[4096];
1109         size_t n = len;
1110
1111         SIVAL(buffer, 0, ((MPLEX_BASE + (int)code)<<24) + len);
1112
1113         /* When the generator reads messages from the msg_fd_in pipe, it can
1114          * cause output to occur down the socket.  Setting contiguous_write_len
1115          * prevents the reading of msg_fd_in once we actually start to write
1116          * this sequence of data (though we might read it before the start). */
1117         if (am_generator && msg_fd_in >= 0)
1118                 contiguous_write_len = len + 4;
1119
1120         if (n > sizeof buffer - 4)
1121                 n = sizeof buffer - 4;
1122
1123         memcpy(&buffer[4], buf, n);
1124         writefd_unbuffered(sock_f_out, buffer, n+4);
1125
1126         len -= n;
1127         buf += n;
1128
1129         if (len)
1130                 writefd_unbuffered(sock_f_out, buf, len);
1131
1132         if (am_generator && msg_fd_in >= 0)
1133                 contiguous_write_len = 0;
1134 }
1135
1136
1137 void io_flush(int flush_it_all)
1138 {
1139         msg_list_push(flush_it_all);
1140
1141         if (!iobuf_out_cnt || no_flush)
1142                 return;
1143
1144         if (io_multiplexing_out)
1145                 mplex_write(MSG_DATA, iobuf_out, iobuf_out_cnt);
1146         else
1147                 writefd_unbuffered(sock_f_out, iobuf_out, iobuf_out_cnt);
1148         iobuf_out_cnt = 0;
1149 }
1150
1151
1152 static void writefd(int fd,char *buf,size_t len)
1153 {
1154         if (fd == msg_fd_out) {
1155                 rprintf(FERROR, "Internal error: wrong write used in receiver.\n");
1156                 exit_cleanup(RERR_PROTOCOL);
1157         }
1158
1159         if (fd == sock_f_out)
1160                 stats.total_written += len;
1161
1162         if (fd == write_batch_monitor_out) {
1163                 if ((size_t)write(batch_fd, buf, len) != len)
1164                         exit_cleanup(RERR_FILEIO);
1165         }
1166
1167         if (!iobuf_out || fd != sock_f_out) {
1168                 writefd_unbuffered(fd, buf, len);
1169                 return;
1170         }
1171
1172         while (len) {
1173                 int n = MIN((int)len, IO_BUFFER_SIZE - iobuf_out_cnt);
1174                 if (n > 0) {
1175                         memcpy(iobuf_out+iobuf_out_cnt, buf, n);
1176                         buf += n;
1177                         len -= n;
1178                         iobuf_out_cnt += n;
1179                 }
1180
1181                 if (iobuf_out_cnt == IO_BUFFER_SIZE)
1182                         io_flush(NORMAL_FLUSH);
1183         }
1184 }
1185
1186
1187 void write_shortint(int f, int x)
1188 {
1189         uchar b[2];
1190         b[0] = x;
1191         b[1] = x >> 8;
1192         writefd(f, (char *)b, 2);
1193 }
1194
1195
1196 void write_int(int f,int32 x)
1197 {
1198         char b[4];
1199         SIVAL(b,0,x);
1200         writefd(f,b,4);
1201 }
1202
1203
1204 void write_int_named(int f, int32 x, const char *phase)
1205 {
1206         io_write_phase = phase;
1207         write_int(f, x);
1208         io_write_phase = phase_unknown;
1209 }
1210
1211
1212 /*
1213  * Note: int64 may actually be a 32-bit type if ./configure couldn't find any
1214  * 64-bit types on this platform.
1215  */
1216 void write_longint(int f, int64 x)
1217 {
1218         char b[8];
1219
1220         if (x <= 0x7FFFFFFF) {
1221                 write_int(f, (int)x);
1222                 return;
1223         }
1224
1225 #if SIZEOF_INT64 < 8
1226         rprintf(FERROR, "Integer overflow: attempted 64-bit offset\n");
1227         exit_cleanup(RERR_UNSUPPORTED);
1228 #else
1229         write_int(f, (int32)0xFFFFFFFF);
1230         SIVAL(b,0,(x&0xFFFFFFFF));
1231         SIVAL(b,4,((x>>32)&0xFFFFFFFF));
1232
1233         writefd(f,b,8);
1234 #endif
1235 }
1236
1237 void write_buf(int f,char *buf,size_t len)
1238 {
1239         writefd(f,buf,len);
1240 }
1241
1242 /** Write a string to the connection */
1243 void write_sbuf(int f, char *buf)
1244 {
1245         writefd(f, buf, strlen(buf));
1246 }
1247
1248 void write_byte(int f, uchar c)
1249 {
1250         writefd(f, (char *)&c, 1);
1251 }
1252
1253 void write_vstring(int f, char *str, int len)
1254 {
1255         uchar lenbuf[3], *lb = lenbuf;
1256
1257         if (len > 0x7F) {
1258                 if (len > 0x7FFF) {
1259                         rprintf(FERROR,
1260                                 "attempting to send over-long vstring (%d > %d)\n",
1261                                 len, 0x7FFF);
1262                         exit_cleanup(RERR_PROTOCOL);
1263                 }
1264                 *lb++ = len / 0x100 + 0x80;
1265         }
1266         *lb = len;
1267
1268         writefd(f, (char*)lenbuf, lb - lenbuf + 1);
1269         if (len)
1270                 writefd(f, str, len);
1271 }
1272
1273
1274 /**
1275  * Read a line of up to @p maxlen characters into @p buf (not counting
1276  * the trailing null).  Strips the (required) trailing newline and all
1277  * carriage returns.
1278  *
1279  * @return 1 for success; 0 for I/O error or truncation.
1280  **/
1281 int read_line(int f, char *buf, size_t maxlen)
1282 {
1283         while (maxlen) {
1284                 buf[0] = 0;
1285                 read_buf(f, buf, 1);
1286                 if (buf[0] == 0)
1287                         return 0;
1288                 if (buf[0] == '\n')
1289                         break;
1290                 if (buf[0] != '\r') {
1291                         buf++;
1292                         maxlen--;
1293                 }
1294         }
1295         *buf = '\0';
1296         return maxlen > 0;
1297 }
1298
1299
1300 void io_printf(int fd, const char *format, ...)
1301 {
1302         va_list ap;
1303         char buf[1024];
1304         int len;
1305
1306         va_start(ap, format);
1307         len = vsnprintf(buf, sizeof buf, format, ap);
1308         va_end(ap);
1309
1310         if (len < 0)
1311                 exit_cleanup(RERR_STREAMIO);
1312
1313         write_sbuf(fd, buf);
1314 }
1315
1316
1317 /** Setup for multiplexing a MSG_* stream with the data stream. */
1318 void io_start_multiplex_out(void)
1319 {
1320         io_flush(NORMAL_FLUSH);
1321         io_start_buffering_out();
1322         io_multiplexing_out = 1;
1323 }
1324
1325 /** Setup for multiplexing a MSG_* stream with the data stream. */
1326 void io_start_multiplex_in(void)
1327 {
1328         io_flush(NORMAL_FLUSH);
1329         io_start_buffering_in();
1330         io_multiplexing_in = 1;
1331 }
1332
1333 /** Write an message to the multiplexed data stream. */
1334 int io_multiplex_write(enum msgcode code, char *buf, size_t len)
1335 {
1336         if (!io_multiplexing_out)
1337                 return 0;
1338
1339         io_flush(NORMAL_FLUSH);
1340         stats.total_written += (len+4);
1341         mplex_write(code, buf, len);
1342         return 1;
1343 }
1344
1345 void close_multiplexing_in(void)
1346 {
1347         io_multiplexing_in = 0;
1348 }
1349
1350 /** Stop output multiplexing. */
1351 void close_multiplexing_out(void)
1352 {
1353         io_multiplexing_out = 0;
1354 }
1355
1356 void start_write_batch(int fd)
1357 {
1358         write_stream_flags(batch_fd);
1359
1360         /* Some communication has already taken place, but we don't
1361          * enable batch writing until here so that we can write a
1362          * canonical record of the communication even though the
1363          * actual communication so far depends on whether a daemon
1364          * is involved. */
1365         write_int(batch_fd, protocol_version);
1366         write_int(batch_fd, checksum_seed);
1367
1368         if (am_sender)
1369                 write_batch_monitor_out = fd;
1370         else
1371                 write_batch_monitor_in = fd;
1372 }
1373
1374 void stop_write_batch(void)
1375 {
1376         write_batch_monitor_out = -1;
1377         write_batch_monitor_in = -1;
1378 }