io.c

   1 /*
   2  * Socket and pipe I/O utilities used in rsync.
   3  *
   4  * Copyright (C) 1996-2001 Andrew Tridgell
   5  * Copyright (C) 1996 Paul Mackerras
   6  * Copyright (C) 2001, 2002 Martin Pool <mbp@samba.org>
   7  * Copyright (C) 2003-2009 Wayne Davison
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 3 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, visit the http://fsf.org website.
  21  */
  22
  23 /* Rsync provides its own multiplexing system, which is used to send
  24  * stderr and stdout over a single socket.
  25  *
  26  * For historical reasons this is off during the start of the
  27  * connection, but it's switched on quite early using
  28  * io_start_multiplex_out() and io_start_multiplex_in(). */
  29
  30 #include "rsync.h"
  31 #include "ifuncs.h"
  32
  33 /** If no timeout is specified then use a 60 second select timeout */
  34 #define SELECT_TIMEOUT 60
  35
  36 extern int bwlimit;
  37 extern size_t bwlimit_writemax;
  38 extern int io_timeout;
  39 extern int allowed_lull;
  40 extern int am_server;
  41 extern int am_daemon;
  42 extern int am_sender;
  43 extern int am_generator;
  44 extern int inc_recurse;
  45 extern int io_error;
  46 extern int eol_nulls;
  47 extern int flist_eof;
  48 extern int list_only;
  49 extern int read_batch;
  50 extern int csum_length;
  51 extern int protect_args;
  52 extern int checksum_seed;
  53 extern int protocol_version;
  54 extern int remove_source_files;
  55 extern int preserve_hard_links;
  56 extern struct stats stats;
  57 extern struct file_list *cur_flist;
  58 #ifdef ICONV_OPTION
  59 extern int filesfrom_convert;
  60 extern iconv_t ic_send, ic_recv;
  61 #endif
  62
  63 const char phase_unknown[] = "unknown";
  64 int ignore_timeout = 0;
  65 int batch_fd = -1;
  66 int msgdone_cnt = 0;
  67
  68 /* Ignore an EOF error if non-zero. See whine_about_eof(). */
  69 int kluge_around_eof = 0;
  70
  71 int msg_fd_in = -1;
  72 int msg_fd_out = -1;
  73 int sock_f_in = -1;
  74 int sock_f_out = -1;
  75
  76 static int iobuf_f_in = -1;
  77 static char *iobuf_in;
  78 static size_t iobuf_in_siz;
  79 static size_t iobuf_in_ndx;
  80 static size_t iobuf_in_remaining;
  81
  82 static int iobuf_f_out = -1;
  83 static char *iobuf_out;
  84 static int iobuf_out_cnt;
  85
  86 int flist_forward_from = -1;
  87
  88 static int io_multiplexing_out;
  89 static int io_multiplexing_in;
  90 static time_t last_io_in;
  91 static time_t last_io_out;
  92 static int no_flush;
  93
  94 static int write_batch_monitor_in = -1;
  95 static int write_batch_monitor_out = -1;
  96
  97 static int io_filesfrom_f_in = -1;
  98 static int io_filesfrom_f_out = -1;
  99 static xbuf ff_buf = EMPTY_XBUF;
 100 static char ff_lastchar;
 101 #ifdef ICONV_OPTION
 102 static xbuf iconv_buf = EMPTY_XBUF;
 103 #endif
 104 static int defer_forwarding_messages = 0, keep_defer_forwarding = 0;
 105 static int select_timeout = SELECT_TIMEOUT;
 106 static int active_filecnt = 0;
 107 static OFF_T active_bytecnt = 0;
 108 static int first_message = 1;
 109
 110 static char int_byte_extra[64] = {
 111         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* (00 - 3F)/4 */
 112         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* (40 - 7F)/4 */
 113         1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* (80 - BF)/4 */
 114         2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 5, 6, /* (C0 - FF)/4 */
 115 };
 116
 117 #define REMOTE_OPTION_ERROR "rsync: on remote machine: -"
 118 #define REMOTE_OPTION_ERROR2 ": unknown option"
 119
 120 enum festatus { FES_SUCCESS, FES_REDO, FES_NO_SEND };
 121
 122 static void check_timeout(void)
 123 {
 124         time_t t, chk;
 125
 126         if (!io_timeout || ignore_timeout)
 127                 return;
 128
 129         t = time(NULL);
 130
 131         if (!last_io_in)
 132                 last_io_in = t;
 133
 134         chk = MAX(last_io_out, last_io_in);
 135         if (t - chk >= io_timeout) {
 136                 if (am_server || am_daemon)
 137                         exit_cleanup(RERR_TIMEOUT);
 138                 rprintf(FERROR, "[%s] io timeout after %d seconds -- exiting\n",
 139                         who_am_i(), (int)(t-chk));
 140                 exit_cleanup(RERR_TIMEOUT);
 141         }
 142 }
 143
 144 static void readfd(int fd, char *buffer, size_t N);
 145 static void writefd(int fd, const char *buf, size_t len);
 146 static void writefd_unbuffered(int fd, const char *buf, size_t len);
 147 static void mplex_write(int fd, enum msgcode code, const char *buf, size_t len, int convert);
 148
 149 static flist_ndx_list redo_list, hlink_list;
 150
 151 struct msg_list_item {
 152         struct msg_list_item *next;
 153         char convert;
 154         char buf[1];
 155 };
 156
 157 struct msg_list {
 158         struct msg_list_item *head, *tail;
 159 };
 160
 161 static struct msg_list msg_queue;
 162
 163 static void got_flist_entry_status(enum festatus status, const char *buf)
 164 {
 165         int ndx = IVAL(buf, 0);
 166         struct file_list *flist = flist_for_ndx(ndx, "got_flist_entry_status");
 167
 168         if (remove_source_files) {
 169                 active_filecnt--;
 170                 active_bytecnt -= F_LENGTH(flist->files[ndx - flist->ndx_start]);
 171         }
 172
 173         if (inc_recurse)
 174                 flist->in_progress--;
 175
 176         switch (status) {
 177         case FES_SUCCESS:
 178                 if (remove_source_files)
 179                         send_msg(MSG_SUCCESS, buf, 4, 0);
 180                 if (preserve_hard_links) {
 181                         struct file_struct *file = flist->files[ndx - flist->ndx_start];
 182                         if (F_IS_HLINKED(file)) {
 183                                 flist_ndx_push(&hlink_list, ndx);
 184                                 flist->in_progress++;
 185                         }
 186                 }
 187                 break;
 188         case FES_REDO:
 189                 if (read_batch) {
 190                         if (inc_recurse)
 191                                 flist->in_progress++;
 192                         break;
 193                 }
 194                 if (inc_recurse)
 195                         flist->to_redo++;
 196                 flist_ndx_push(&redo_list, ndx);
 197                 break;
 198         case FES_NO_SEND:
 199                 break;
 200         }
 201 }
 202
 203 /* Note the fds used for the main socket (which might really be a pipe
 204  * for a local transfer, but we can ignore that). */
 205 void io_set_sock_fds(int f_in, int f_out)
 206 {
 207         sock_f_in = f_in;
 208         sock_f_out = f_out;
 209 }
 210
 211 void set_io_timeout(int secs)
 212 {
 213         io_timeout = secs;
 214         allowed_lull = (io_timeout + 1) / 2;
 215
 216         if (!io_timeout || allowed_lull > SELECT_TIMEOUT)
 217                 select_timeout = SELECT_TIMEOUT;
 218         else
 219                 select_timeout = allowed_lull;
 220
 221         if (read_batch)
 222                 allowed_lull = 0;
 223 }
 224
 225 /* Setup the fd used to receive MSG_* messages.  Only needed during the
 226  * early stages of being a local sender (up through the sending of the
 227  * file list) or when we're the generator (to fetch the messages from
 228  * the receiver). */
 229 void set_msg_fd_in(int fd)
 230 {
 231         msg_fd_in = fd;
 232 }
 233
 234 /* Setup the fd used to send our MSG_* messages.  Only needed when
 235  * we're the receiver (to send our messages to the generator). */
 236 void set_msg_fd_out(int fd)
 237 {
 238         msg_fd_out = fd;
 239         set_nonblocking(msg_fd_out);
 240 }
 241
 242 /* Add a message to the pending MSG_* list. */
 243 static void msg_list_add(struct msg_list *lst, int code, const char *buf, int len, int convert)
 244 {
 245         struct msg_list_item *m;
 246         int sz = len + 4 + sizeof m[0] - 1;
 247
 248         if (!(m = (struct msg_list_item *)new_array(char, sz)))
 249                 out_of_memory("msg_list_add");
 250         m->next = NULL;
 251         m->convert = convert;
 252         SIVAL(m->buf, 0, ((code+MPLEX_BASE)<<24) | len);
 253         memcpy(m->buf + 4, buf, len);
 254         if (lst->tail)
 255                 lst->tail->next = m;
 256         else
 257                 lst->head = m;
 258         lst->tail = m;
 259 }
 260
 261 static inline int flush_a_msg(int fd)
 262 {
 263         struct msg_list_item *m = msg_queue.head;
 264         int len = IVAL(m->buf, 0) & 0xFFFFFF;
 265         int tag = *((uchar*)m->buf+3) - MPLEX_BASE;
 266
 267         if (!(msg_queue.head = m->next))
 268                 msg_queue.tail = NULL;
 269
 270         defer_forwarding_messages++;
 271         mplex_write(fd, tag, m->buf + 4, len, m->convert);
 272         defer_forwarding_messages--;
 273
 274         free(m);
 275
 276         return len;
 277 }
 278
 279 static void msg_flush(void)
 280 {
 281         if (am_generator) {
 282                 while (msg_queue.head && io_multiplexing_out)
 283                         stats.total_written += flush_a_msg(sock_f_out) + 4;
 284         } else {
 285                 while (msg_queue.head)
 286                         (void)flush_a_msg(msg_fd_out);
 287         }
 288 }
 289
 290 static void check_for_d_option_error(const char *msg)
 291 {
 292         static char rsync263_opts[] = "BCDHIKLPRSTWabceghlnopqrtuvxz";
 293         char *colon;
 294         int saw_d = 0;
 295
 296         if (*msg != 'r'
 297          || strncmp(msg, REMOTE_OPTION_ERROR, sizeof REMOTE_OPTION_ERROR - 1) != 0)
 298                 return;
 299
 300         msg += sizeof REMOTE_OPTION_ERROR - 1;
 301         if (*msg == '-' || (colon = strchr(msg, ':')) == NULL
 302          || strncmp(colon, REMOTE_OPTION_ERROR2, sizeof REMOTE_OPTION_ERROR2 - 1) != 0)
 303                 return;
 304
 305         for ( ; *msg != ':'; msg++) {
 306                 if (*msg == 'd')
 307                         saw_d = 1;
 308                 else if (*msg == 'e')
 309                         break;
 310                 else if (strchr(rsync263_opts, *msg) == NULL)
 311                         return;
 312         }
 313
 314         if (saw_d) {
 315                 rprintf(FWARNING,
 316                     "*** Try using \"--old-d\" if remote rsync is <= 2.6.3 ***\n");
 317         }
 318 }
 319
 320 /* Read a message from the MSG_* fd and handle it.  This is called either
 321  * during the early stages of being a local sender (up through the sending
 322  * of the file list) or when we're the generator (to fetch the messages
 323  * from the receiver). */
 324 static void read_msg_fd(void)
 325 {
 326         char buf[2048];
 327         size_t n;
 328         struct file_list *flist;
 329         int fd = msg_fd_in;
 330         int tag, len;
 331
 332         /* Temporarily disable msg_fd_in.  This is needed to avoid looping back
 333          * to this routine from writefd_unbuffered(). */
 334         no_flush++;
 335         msg_fd_in = -1;
 336         defer_forwarding_messages++;
 337
 338         readfd(fd, buf, 4);
 339         tag = IVAL(buf, 0);
 340
 341         len = tag & 0xFFFFFF;
 342         tag = (tag >> 24) - MPLEX_BASE;
 343
 344         switch (tag) {
 345         case MSG_DONE:
 346                 if (len < 0 || len > 1 || !am_generator) {
 347                   invalid_msg:
 348                         rprintf(FERROR, "invalid message %d:%d [%s%s]\n",
 349                                 tag, len, who_am_i(),
 350                                 inc_recurse ? "/inc" : "");
 351                         exit_cleanup(RERR_STREAMIO);
 352                 }
 353                 if (len) {
 354                         readfd(fd, buf, len);
 355                         stats.total_read = read_varlong(fd, 3);
 356                 }
 357                 msgdone_cnt++;
 358                 break;
 359         case MSG_REDO:
 360                 if (len != 4 || !am_generator)
 361                         goto invalid_msg;
 362                 readfd(fd, buf, 4);
 363                 got_flist_entry_status(FES_REDO, buf);
 364                 break;
 365         case MSG_FLIST:
 366                 if (len != 4 || !am_generator || !inc_recurse)
 367                         goto invalid_msg;
 368                 readfd(fd, buf, 4);
 369                 /* Read extra file list from receiver. */
 370                 assert(iobuf_in != NULL);
 371                 assert(iobuf_f_in == fd);
 372                 if (verbose > 3) {
 373                         rprintf(FINFO, "[%s] receiving flist for dir %d\n",
 374                                 who_am_i(), IVAL(buf,0));
 375                 }
 376                 flist = recv_file_list(fd);
 377                 flist->parent_ndx = IVAL(buf,0);
 378 #ifdef SUPPORT_HARD_LINKS
 379                 if (preserve_hard_links)
 380                         match_hard_links(flist);
 381 #endif
 382                 break;
 383         case MSG_FLIST_EOF:
 384                 if (len != 0 || !am_generator || !inc_recurse)
 385                         goto invalid_msg;
 386                 flist_eof = 1;
 387                 break;
 388         case MSG_IO_ERROR:
 389                 if (len != 4)
 390                         goto invalid_msg;
 391                 readfd(fd, buf, len);
 392                 io_error |= IVAL(buf, 0);
 393                 break;
 394         case MSG_DELETED:
 395                 if (len >= (int)sizeof buf || !am_generator)
 396                         goto invalid_msg;
 397                 readfd(fd, buf, len);
 398                 send_msg(MSG_DELETED, buf, len, 1);
 399                 break;
 400         case MSG_SUCCESS:
 401                 if (len != 4 || !am_generator)
 402                         goto invalid_msg;
 403                 readfd(fd, buf, 4);
 404                 got_flist_entry_status(FES_SUCCESS, buf);
 405                 break;
 406         case MSG_NO_SEND:
 407                 if (len != 4 || !am_generator)
 408                         goto invalid_msg;
 409                 readfd(fd, buf, 4);
 410                 got_flist_entry_status(FES_NO_SEND, buf);
 411                 break;
 412         case MSG_ERROR_SOCKET:
 413         case MSG_ERROR_UTF8:
 414         case MSG_CLIENT:
 415                 if (!am_generator)
 416                         goto invalid_msg;
 417                 if (tag == MSG_ERROR_SOCKET)
 418                         io_end_multiplex_out();
 419                 /* FALL THROUGH */
 420         case MSG_INFO:
 421         case MSG_ERROR:
 422         case MSG_ERROR_XFER:
 423         case MSG_WARNING:
 424         case MSG_LOG:
 425                 while (len) {
 426                         n = len;
 427                         if (n >= sizeof buf)
 428                                 n = sizeof buf - 1;
 429                         readfd(fd, buf, n);
 430                         rwrite((enum logcode)tag, buf, n, !am_generator);
 431                         len -= n;
 432                 }
 433                 break;
 434         default:
 435                 rprintf(FERROR, "unknown message %d:%d [%s]\n",
 436                         tag, len, who_am_i());
 437                 exit_cleanup(RERR_STREAMIO);
 438         }
 439
 440         no_flush--;
 441         msg_fd_in = fd;
 442         if (!--defer_forwarding_messages && !no_flush)
 443                 msg_flush();
 444 }
 445
 446 /* This is used by the generator to limit how many file transfers can
 447  * be active at once when --remove-source-files is specified.  Without
 448  * this, sender-side deletions were mostly happening at the end. */
 449 void increment_active_files(int ndx, int itemizing, enum logcode code)
 450 {
 451         while (1) {
 452                 /* TODO: tune these limits? */
 453                 int limit = active_bytecnt >= 128*1024 ? 10 : 50;
 454                 if (active_filecnt < limit)
 455                         break;
 456                 check_for_finished_files(itemizing, code, 0);
 457                 if (active_filecnt < limit)
 458                         break;
 459                 if (iobuf_out_cnt)
 460                         io_flush(NORMAL_FLUSH);
 461                 else
 462                         read_msg_fd();
 463         }
 464
 465         active_filecnt++;
 466         active_bytecnt += F_LENGTH(cur_flist->files[ndx - cur_flist->ndx_start]);
 467 }
 468
 469 /* Write an message to a multiplexed stream. If this fails, rsync exits. */
 470 static void mplex_write(int fd, enum msgcode code, const char *buf, size_t len, int convert)
 471 {
 472         char buffer[BIGPATHBUFLEN]; /* Oversized for use by iconv code. */
 473         size_t n = len;
 474
 475 #ifdef ICONV_OPTION
 476         /* We need to convert buf before doing anything else so that we
 477          * can include the (converted) byte length in the message header. */
 478         if (convert && ic_send != (iconv_t)-1) {
 479                 xbuf outbuf, inbuf;
 480
 481                 INIT_XBUF(outbuf, buffer + 4, 0, sizeof buffer - 4);
 482                 INIT_XBUF(inbuf, (char*)buf, len, -1);
 483
 484                 iconvbufs(ic_send, &inbuf, &outbuf,
 485                           ICB_INCLUDE_BAD | ICB_INCLUDE_INCOMPLETE);
 486                 if (inbuf.len > 0) {
 487                         rprintf(FERROR, "overflowed conversion buffer in mplex_write");
 488                         exit_cleanup(RERR_UNSUPPORTED);
 489                 }
 490
 491                 n = len = outbuf.len;
 492         } else
 493 #endif
 494         if (n > 1024 - 4) /* BIGPATHBUFLEN can handle 1024 bytes */
 495                 n = 0;    /* We'd rather do 2 writes than too much memcpy(). */
 496         else
 497                 memcpy(buffer + 4, buf, n);
 498
 499         SIVAL(buffer, 0, ((MPLEX_BASE + (int)code)<<24) + len);
 500
 501         keep_defer_forwarding++; /* defer_forwarding_messages++ on return */
 502         writefd_unbuffered(fd, buffer, n+4);
 503         keep_defer_forwarding--;
 504
 505         if (len > n)
 506                 writefd_unbuffered(fd, buf+n, len-n);
 507
 508         if (!--defer_forwarding_messages && !no_flush)
 509                 msg_flush();
 510 }
 511
 512 int send_msg(enum msgcode code, const char *buf, int len, int convert)
 513 {
 514         if (msg_fd_out < 0) {
 515                 if (!defer_forwarding_messages)
 516                         return io_multiplex_write(code, buf, len, convert);
 517                 if (!io_multiplexing_out)
 518                         return 0;
 519                 msg_list_add(&msg_queue, code, buf, len, convert);
 520                 return 1;
 521         }
 522         if (flist_forward_from >= 0)
 523                 msg_list_add(&msg_queue, code, buf, len, convert);
 524         else
 525                 mplex_write(msg_fd_out, code, buf, len, convert);
 526         return 1;
 527 }
 528
 529 void send_msg_int(enum msgcode code, int num)
 530 {
 531         char numbuf[4];
 532         SIVAL(numbuf, 0, num);
 533         send_msg(code, numbuf, 4, 0);
 534 }
 535
 536 void wait_for_receiver(void)
 537 {
 538         if (io_flush(NORMAL_FLUSH))
 539                 return;
 540         read_msg_fd();
 541 }
 542
 543 int get_redo_num(void)
 544 {
 545         return flist_ndx_pop(&redo_list);
 546 }
 547
 548 int get_hlink_num(void)
 549 {
 550         return flist_ndx_pop(&hlink_list);
 551 }
 552
 553 /**
 554  * When we're the receiver and we have a local --files-from list of names
 555  * that needs to be sent over the socket to the sender, we have to do two
 556  * things at the same time: send the sender a list of what files we're
 557  * processing and read the incoming file+info list from the sender.  We do
 558  * this by augmenting the read_timeout() function to copy this data.  It
 559  * uses ff_buf to read a block of data from f_in (when it is ready, since
 560  * it might be a pipe) and then blast it out f_out (when it is ready to
 561  * receive more data).
 562  */
 563 void io_set_filesfrom_fds(int f_in, int f_out)
 564 {
 565         io_filesfrom_f_in = f_in;
 566         io_filesfrom_f_out = f_out;
 567         alloc_xbuf(&ff_buf, 2048);
 568 #ifdef ICONV_OPTION
 569         if (protect_args)
 570                 alloc_xbuf(&iconv_buf, 1024);
 571 #endif
 572 }
 573
 574 /* It's almost always an error to get an EOF when we're trying to read from the
 575  * network, because the protocol is (for the most part) self-terminating.
 576  *
 577  * There is one case for the receiver when it is at the end of the transfer
 578  * (hanging around reading any keep-alive packets that might come its way): if
 579  * the sender dies before the generator's kill-signal comes through, we can end
 580  * up here needing to loop until the kill-signal arrives.  In this situation,
 581  * kluge_around_eof will be < 0.
 582  *
 583  * There is another case for older protocol versions (< 24) where the module
 584  * listing was not terminated, so we must ignore an EOF error in that case and
 585  * exit.  In this situation, kluge_around_eof will be > 0. */
 586 static void whine_about_eof(int fd)
 587 {
 588         if (kluge_around_eof && fd == sock_f_in) {
 589                 int i;
 590                 if (kluge_around_eof > 0)
 591                         exit_cleanup(0);
 592                 /* If we're still here after 10 seconds, exit with an error. */
 593                 for (i = 10*1000/20; i--; )
 594                         msleep(20);
 595         }
 596
 597         rprintf(FERROR, RSYNC_NAME ": connection unexpectedly closed "
 598                 "(%.0f bytes received so far) [%s]\n",
 599                 (double)stats.total_read, who_am_i());
 600
 601         exit_cleanup(RERR_STREAMIO);
 602 }
 603
 604 /**
 605  * Read from a socket with I/O timeout. return the number of bytes
 606  * read. If no bytes can be read then exit, never return a number <= 0.
 607  *
 608  * TODO: If the remote shell connection fails, then current versions
 609  * actually report an "unexpected EOF" error here.  Since it's a
 610  * fairly common mistake to try to use rsh when ssh is required, we
 611  * should trap that: if we fail to read any data at all, we should
 612  * give a better explanation.  We can tell whether the connection has
 613  * started by looking e.g. at whether the remote version is known yet.
 614  */
 615 static int read_timeout(int fd, char *buf, size_t len)
 616 {
 617         int n, cnt = 0;
 618
 619         io_flush(FULL_FLUSH);
 620
 621         while (cnt == 0) {
 622                 /* until we manage to read *something* */
 623                 fd_set r_fds, w_fds;
 624                 struct timeval tv;
 625                 int maxfd = fd;
 626                 int count;
 627
 628                 FD_ZERO(&r_fds);
 629                 FD_ZERO(&w_fds);
 630                 FD_SET(fd, &r_fds);
 631                 if (io_filesfrom_f_out >= 0) {
 632                         int new_fd;
 633                         if (ff_buf.len == 0) {
 634                                 if (io_filesfrom_f_in >= 0) {
 635                                         FD_SET(io_filesfrom_f_in, &r_fds);
 636                                         new_fd = io_filesfrom_f_in;
 637                                 } else {
 638                                         io_filesfrom_f_out = -1;
 639                                         new_fd = -1;
 640                                 }
 641                         } else {
 642                                 FD_SET(io_filesfrom_f_out, &w_fds);
 643                                 new_fd = io_filesfrom_f_out;
 644                         }
 645                         if (new_fd > maxfd)
 646                                 maxfd = new_fd;
 647                 }
 648
 649                 tv.tv_sec = select_timeout;
 650                 tv.tv_usec = 0;
 651
 652                 errno = 0;
 653
 654                 count = select(maxfd + 1, &r_fds, &w_fds, NULL, &tv);
 655
 656                 if (count <= 0) {
 657                         if (errno == EBADF) {
 658                                 defer_forwarding_messages = 0;
 659                                 exit_cleanup(RERR_SOCKETIO);
 660                         }
 661                         check_timeout();
 662                         continue;
 663                 }
 664
 665                 if (io_filesfrom_f_out >= 0) {
 666                         if (ff_buf.len) {
 667                                 if (FD_ISSET(io_filesfrom_f_out, &w_fds)) {
 668                                         int l = write(io_filesfrom_f_out,
 669                                                       ff_buf.buf + ff_buf.pos,
 670                                                       ff_buf.len);
 671                                         if (l > 0) {
 672                                                 if (!(ff_buf.len -= l))
 673                                                         ff_buf.pos = 0;
 674                                                 else
 675                                                         ff_buf.pos += l;
 676                                         } else if (errno != EINTR) {
 677                                                 /* XXX should we complain? */
 678                                                 io_filesfrom_f_out = -1;
 679                                         }
 680                                 }
 681                         } else if (io_filesfrom_f_in >= 0) {
 682                                 if (FD_ISSET(io_filesfrom_f_in, &r_fds)) {
 683 #ifdef ICONV_OPTION
 684                                         xbuf *ibuf = filesfrom_convert ? &iconv_buf : &ff_buf;
 685 #else
 686                                         xbuf *ibuf = &ff_buf;
 687 #endif
 688                                         int l = read(io_filesfrom_f_in, ibuf->buf, ibuf->size);
 689                                         if (l <= 0) {
 690                                                 if (l == 0 || errno != EINTR) {
 691                                                         /* Send end-of-file marker */
 692                                                         memcpy(ff_buf.buf, "\0\0", 2);
 693                                                         ff_buf.len = ff_lastchar? 2 : 1;
 694                                                         ff_buf.pos = 0;
 695                                                         io_filesfrom_f_in = -1;
 696                                                 }
 697                                         } else {
 698 #ifdef ICONV_OPTION
 699                                                 if (filesfrom_convert) {
 700                                                         iconv_buf.pos = 0;
 701                                                         iconv_buf.len = l;
 702                                                         iconvbufs(ic_send, &iconv_buf, &ff_buf,
 703                                                             ICB_EXPAND_OUT|ICB_INCLUDE_BAD|ICB_INCLUDE_INCOMPLETE);
 704                                                         l = ff_buf.len;
 705                                                 }
 706 #endif
 707                                                 if (!eol_nulls) {
 708                                                         char *s = ff_buf.buf + l;
 709                                                         /* Transform CR and/or LF into '\0' */
 710                                                         while (s-- > ff_buf.buf) {
 711                                                                 if (*s == '\n' || *s == '\r')
 712                                                                         *s = '\0';
 713                                                         }
 714                                                 }
 715                                                 if (!ff_lastchar) {
 716                                                         /* Last buf ended with a '\0', so don't
 717                                                          * let this buf start with one. */
 718                                                         while (l && ff_buf.buf[ff_buf.pos] == '\0')
 719                                                                 ff_buf.pos++, l--;
 720                                                 }
 721                                                 if (!l)
 722                                                         ff_buf.pos = 0;
 723                                                 else {
 724                                                         char *f = ff_buf.buf + ff_buf.pos;
 725                                                         char *t = f;
 726                                                         char *eob = f + l;
 727                                                         /* Eliminate any multi-'\0' runs. */
 728                                                         while (f != eob) {
 729                                                                 if (!(*t++ = *f++)) {
 730                                                                         while (f != eob && !*f)
 731                                                                                 f++, l--;
 732                                                                 }
 733                                                         }
 734                                                         ff_lastchar = f[-1];
 735                                                 }
 736                                                 ff_buf.len = l;
 737                                         }
 738                                 }
 739                         }
 740                 }
 741
 742                 if (!FD_ISSET(fd, &r_fds))
 743                         continue;
 744
 745                 n = read(fd, buf, len);
 746
 747                 if (n <= 0) {
 748                         if (n == 0)
 749                                 whine_about_eof(fd); /* Doesn't return. */
 750                         if (errno == EINTR || errno == EWOULDBLOCK
 751                             || errno == EAGAIN)
 752                                 continue;
 753
 754                         /* Don't write errors on a dead socket. */
 755                         if (fd == sock_f_in) {
 756                                 io_end_multiplex_out();
 757                                 rsyserr(FERROR_SOCKET, errno, "read error");
 758                         } else
 759                                 rsyserr(FERROR, errno, "read error");
 760                         exit_cleanup(RERR_STREAMIO);
 761                 }
 762
 763                 buf += n;
 764                 len -= n;
 765                 cnt += n;
 766
 767                 if (fd == sock_f_in && io_timeout)
 768                         last_io_in = time(NULL);
 769         }
 770
 771         return cnt;
 772 }
 773
 774 /* Read a line into the "buf" buffer. */
 775 int read_line(int fd, char *buf, size_t bufsiz, int flags)
 776 {
 777         char ch, *s, *eob;
 778         int cnt;
 779
 780 #ifdef ICONV_OPTION
 781         if (flags & RL_CONVERT && iconv_buf.size < bufsiz)
 782                 realloc_xbuf(&iconv_buf, bufsiz + 1024);
 783 #endif
 784
 785   start:
 786 #ifdef ICONV_OPTION
 787         s = flags & RL_CONVERT ? iconv_buf.buf : buf;
 788 #else
 789         s = buf;
 790 #endif
 791         eob = s + bufsiz - 1;
 792         while (1) {
 793                 cnt = read(fd, &ch, 1);
 794                 if (cnt < 0 && (errno == EWOULDBLOCK
 795                   || errno == EINTR || errno == EAGAIN)) {
 796                         struct timeval tv;
 797                         fd_set r_fds, e_fds;
 798                         FD_ZERO(&r_fds);
 799                         FD_SET(fd, &r_fds);
 800                         FD_ZERO(&e_fds);
 801                         FD_SET(fd, &e_fds);
 802                         tv.tv_sec = select_timeout;
 803                         tv.tv_usec = 0;
 804                         if (!select(fd+1, &r_fds, NULL, &e_fds, &tv))
 805                                 check_timeout();
 806                         /*if (FD_ISSET(fd, &e_fds))
 807                                 rprintf(FINFO, "select exception on fd %d\n", fd); */
 808                         continue;
 809                 }
 810                 if (cnt != 1)
 811                         break;
 812                 if (flags & RL_EOL_NULLS ? ch == '\0' : (ch == '\r' || ch == '\n')) {
 813                         /* Skip empty lines if dumping comments. */
 814                         if (flags & RL_DUMP_COMMENTS && s == buf)
 815                                 continue;
 816                         break;
 817                 }
 818                 if (s < eob)
 819                         *s++ = ch;
 820         }
 821         *s = '\0';
 822
 823         if (flags & RL_DUMP_COMMENTS && (*buf == '#' || *buf == ';'))
 824                 goto start;
 825
 826 #ifdef ICONV_OPTION
 827         if (flags & RL_CONVERT) {
 828                 xbuf outbuf;
 829                 INIT_XBUF(outbuf, buf, 0, bufsiz);
 830                 iconv_buf.pos = 0;
 831                 iconv_buf.len = s - iconv_buf.buf;
 832                 iconvbufs(ic_recv, &iconv_buf, &outbuf,
 833                           ICB_INCLUDE_BAD | ICB_INCLUDE_INCOMPLETE);
 834                 outbuf.buf[outbuf.len] = '\0';
 835                 return outbuf.len;
 836         }
 837 #endif
 838
 839         return s - buf;
 840 }
 841
 842 void read_args(int f_in, char *mod_name, char *buf, size_t bufsiz, int rl_nulls,
 843                char ***argv_p, int *argc_p, char **request_p)
 844 {
 845         int maxargs = MAX_ARGS;
 846         int dot_pos = 0;
 847         int argc = 0;
 848         char **argv, *p;
 849         int rl_flags = (rl_nulls ? RL_EOL_NULLS : 0);
 850
 851 #ifdef ICONV_OPTION
 852         rl_flags |= (protect_args && ic_recv != (iconv_t)-1 ? RL_CONVERT : 0);
 853 #endif
 854
 855         if (!(argv = new_array(char *, maxargs)))
 856                 out_of_memory("read_args");
 857         if (mod_name && !protect_args)
 858                 argv[argc++] = "rsyncd";
 859
 860         while (1) {
 861                 if (read_line(f_in, buf, bufsiz, rl_flags) == 0)
 862                         break;
 863
 864                 if (argc == maxargs-1) {
 865                         maxargs += MAX_ARGS;
 866                         if (!(argv = realloc_array(argv, char *, maxargs)))
 867                                 out_of_memory("read_args");
 868                 }
 869
 870                 if (dot_pos) {
 871                         if (request_p) {
 872                                 *request_p = strdup(buf);
 873                                 request_p = NULL;
 874                         }
 875                         if (mod_name)
 876                                 glob_expand_module(mod_name, buf, &argv, &argc, &maxargs);
 877                         else
 878                                 glob_expand(buf, &argv, &argc, &maxargs);
 879                 } else {
 880                         if (!(p = strdup(buf)))
 881                                 out_of_memory("read_args");
 882                         argv[argc++] = p;
 883                         if (*p == '.' && p[1] == '\0')
 884                                 dot_pos = argc;
 885                 }
 886         }
 887         argv[argc] = NULL;
 888
 889         glob_expand(NULL, NULL, NULL, NULL);
 890
 891         *argc_p = argc;
 892         *argv_p = argv;
 893 }
 894
 895 int io_start_buffering_out(int f_out)
 896 {
 897         if (iobuf_out) {
 898                 assert(f_out == iobuf_f_out);
 899                 return 0;
 900         }
 901         if (!(iobuf_out = new_array(char, IO_BUFFER_SIZE)))
 902                 out_of_memory("io_start_buffering_out");
 903         iobuf_out_cnt = 0;
 904         iobuf_f_out = f_out;
 905         return 1;
 906 }
 907
 908 int io_start_buffering_in(int f_in)
 909 {
 910         if (iobuf_in) {
 911                 assert(f_in == iobuf_f_in);
 912                 return 0;
 913         }
 914         iobuf_in_siz = 2 * IO_BUFFER_SIZE;
 915         if (!(iobuf_in = new_array(char, iobuf_in_siz)))
 916                 out_of_memory("io_start_buffering_in");
 917         iobuf_f_in = f_in;
 918         return 1;
 919 }
 920
 921 void io_end_buffering_in(void)
 922 {
 923         if (!iobuf_in)
 924                 return;
 925         free(iobuf_in);
 926         iobuf_in = NULL;
 927         iobuf_in_ndx = 0;
 928         iobuf_in_remaining = 0;
 929         iobuf_f_in = -1;
 930 }
 931
 932 void io_end_buffering_out(void)
 933 {
 934         if (!iobuf_out)
 935                 return;
 936         io_flush(FULL_FLUSH);
 937         free(iobuf_out);
 938         iobuf_out = NULL;
 939         iobuf_f_out = -1;
 940 }
 941
 942 void maybe_flush_socket(int important)
 943 {
 944         if (iobuf_out && iobuf_out_cnt
 945          && (important || time(NULL) - last_io_out >= 5))
 946                 io_flush(NORMAL_FLUSH);
 947 }
 948
 949 void maybe_send_keepalive(void)
 950 {
 951         if (time(NULL) - last_io_out >= allowed_lull) {
 952                 if (!iobuf_out || !iobuf_out_cnt) {
 953                         if (protocol_version < 29)
 954                                 send_msg(MSG_DATA, "", 0, 0);
 955                         else if (protocol_version >= 30)
 956                                 send_msg(MSG_NOOP, "", 0, 0);
 957                         else {
 958                                 write_int(sock_f_out, cur_flist->used);
 959                                 write_shortint(sock_f_out, ITEM_IS_NEW);
 960                         }
 961                 }
 962                 if (iobuf_out)
 963                         io_flush(NORMAL_FLUSH);
 964         }
 965 }
 966
 967 void start_flist_forward(int f_in)
 968 {
 969         assert(iobuf_out != NULL);
 970         assert(iobuf_f_out == msg_fd_out);
 971         flist_forward_from = f_in;
 972         defer_forwarding_messages++;
 973 }
 974
 975 void stop_flist_forward(void)
 976 {
 977         flist_forward_from = -1;
 978         defer_forwarding_messages--;
 979         io_flush(FULL_FLUSH);
 980 }
 981
 982 /**
 983  * Continue trying to read len bytes - don't return until len has been
 984  * read.
 985  **/
 986 static void read_loop(int fd, char *buf, size_t len)
 987 {
 988         while (len) {
 989                 int n = read_timeout(fd, buf, len);
 990
 991                 buf += n;
 992                 len -= n;
 993         }
 994 }
 995
 996 /**
 997  * Read from the file descriptor handling multiplexing - return number
 998  * of bytes read.
 999  *
1000  * Never returns <= 0.
1001  */
1002 static int readfd_unbuffered(int fd, char *buf, size_t len)
1003 {
1004         size_t msg_bytes;
1005         int tag, cnt = 0;
1006         char line[BIGPATHBUFLEN];
1007
1008         if (!iobuf_in || fd != iobuf_f_in)
1009                 return read_timeout(fd, buf, len);
1010
1011         if (!io_multiplexing_in && iobuf_in_remaining == 0) {
1012                 iobuf_in_remaining = read_timeout(fd, iobuf_in, iobuf_in_siz);
1013                 iobuf_in_ndx = 0;
1014         }
1015
1016         while (cnt == 0) {
1017                 if (iobuf_in_remaining) {
1018                         len = MIN(len, iobuf_in_remaining);
1019                         memcpy(buf, iobuf_in + iobuf_in_ndx, len);
1020                         iobuf_in_ndx += len;
1021                         iobuf_in_remaining -= len;
1022                         cnt = len;
1023                         break;
1024                 }
1025
1026                 read_loop(fd, line, 4);
1027                 tag = IVAL(line, 0);
1028
1029                 msg_bytes = tag & 0xFFFFFF;
1030                 tag = (tag >> 24) - MPLEX_BASE;
1031
1032                 switch (tag) {
1033                 case MSG_DATA:
1034                         if (msg_bytes > iobuf_in_siz) {
1035                                 if (!(iobuf_in = realloc_array(iobuf_in, char,
1036                                                                msg_bytes)))
1037                                         out_of_memory("readfd_unbuffered");
1038                                 iobuf_in_siz = msg_bytes;
1039                         }
1040                         read_loop(fd, iobuf_in, msg_bytes);
1041                         iobuf_in_remaining = msg_bytes;
1042                         iobuf_in_ndx = 0;
1043                         break;
1044                 case MSG_NOOP:
1045                         if (msg_bytes != 0)
1046                                 goto invalid_msg;
1047                         if (am_sender)
1048                                 maybe_send_keepalive();
1049                         break;
1050                 case MSG_IO_ERROR:
1051                         if (msg_bytes != 4)
1052                                 goto invalid_msg;
1053                         read_loop(fd, line, msg_bytes);
1054                         send_msg_int(MSG_IO_ERROR, IVAL(line, 0));
1055                         io_error |= IVAL(line, 0);
1056                         break;
1057                 case MSG_DELETED:
1058                         if (msg_bytes >= sizeof line)
1059                                 goto overflow;
1060 #ifdef ICONV_OPTION
1061                         if (ic_recv != (iconv_t)-1) {
1062                                 xbuf outbuf, inbuf;
1063                                 char ibuf[512];
1064                                 int add_null = 0;
1065                                 int pos = 0;
1066
1067                                 INIT_CONST_XBUF(outbuf, line);
1068                                 INIT_XBUF(inbuf, ibuf, 0, -1);
1069
1070                                 while (msg_bytes) {
1071                                         inbuf.len = msg_bytes > sizeof ibuf
1072                                                   ? sizeof ibuf : msg_bytes;
1073                                         read_loop(fd, inbuf.buf, inbuf.len);
1074                                         if (!(msg_bytes -= inbuf.len)
1075                                          && !ibuf[inbuf.len-1])
1076                                                 inbuf.len--, add_null = 1;
1077                                         if (iconvbufs(ic_send, &inbuf, &outbuf,
1078                                             ICB_INCLUDE_BAD | ICB_INCLUDE_INCOMPLETE) < 0)
1079                                                 goto overflow;
1080                                         pos = -1;
1081                                 }
1082                                 if (add_null) {
1083                                         if (outbuf.len == outbuf.size)
1084                                                 goto overflow;
1085                                         outbuf.buf[outbuf.len++] = '\0';
1086                                 }
1087                                 msg_bytes = outbuf.len;
1088                         } else
1089 #endif
1090                                 read_loop(fd, line, msg_bytes);
1091                         /* A directory name was sent with the trailing null */
1092                         if (msg_bytes > 0 && !line[msg_bytes-1])
1093                                 log_delete(line, S_IFDIR);
1094                         else {
1095                                 line[msg_bytes] = '\0';
1096                                 log_delete(line, S_IFREG);
1097                         }
1098                         break;
1099                 case MSG_SUCCESS:
1100                         if (msg_bytes != 4) {
1101                           invalid_msg:
1102                                 rprintf(FERROR, "invalid multi-message %d:%ld [%s]\n",
1103                                         tag, (long)msg_bytes, who_am_i());
1104                                 exit_cleanup(RERR_STREAMIO);
1105                         }
1106                         read_loop(fd, line, msg_bytes);
1107                         successful_send(IVAL(line, 0));
1108                         break;
1109                 case MSG_NO_SEND:
1110                         if (msg_bytes != 4)
1111                                 goto invalid_msg;
1112                         read_loop(fd, line, msg_bytes);
1113                         send_msg_int(MSG_NO_SEND, IVAL(line, 0));
1114                         break;
1115                 case MSG_INFO:
1116                 case MSG_ERROR:
1117                 case MSG_ERROR_XFER:
1118                 case MSG_WARNING:
1119                         if (msg_bytes >= sizeof line) {
1120                             overflow:
1121                                 rprintf(FERROR,
1122                                         "multiplexing overflow %d:%ld [%s]\n",
1123                                         tag, (long)msg_bytes, who_am_i());
1124                                 exit_cleanup(RERR_STREAMIO);
1125                         }
1126                         read_loop(fd, line, msg_bytes);
1127                         rwrite((enum logcode)tag, line, msg_bytes, 1);
1128                         if (first_message) {
1129                                 if (list_only && !am_sender && tag == 1) {
1130                                         line[msg_bytes] = '\0';
1131                                         check_for_d_option_error(line);
1132                                 }
1133                                 first_message = 0;
1134                         }
1135                         break;
1136                 default:
1137                         rprintf(FERROR, "unexpected tag %d [%s]\n",
1138                                 tag, who_am_i());
1139                         exit_cleanup(RERR_STREAMIO);
1140                 }
1141         }
1142
1143         if (iobuf_in_remaining == 0)
1144                 io_flush(NORMAL_FLUSH);
1145
1146         return cnt;
1147 }
1148
1149 /* Do a buffered read from fd.  Don't return until all N bytes have
1150  * been read.  If all N can't be read then exit with an error. */
1151 static void readfd(int fd, char *buffer, size_t N)
1152 {
1153         int  cnt;
1154         size_t total = 0;
1155
1156         while (total < N) {
1157                 cnt = readfd_unbuffered(fd, buffer + total, N-total);
1158                 total += cnt;
1159         }
1160
1161         if (fd == write_batch_monitor_in) {
1162                 if ((size_t)write(batch_fd, buffer, total) != total)
1163                         exit_cleanup(RERR_FILEIO);
1164         }
1165
1166         if (fd == flist_forward_from)
1167                 writefd(iobuf_f_out, buffer, total);
1168
1169         if (fd == sock_f_in)
1170                 stats.total_read += total;
1171 }
1172
1173 unsigned short read_shortint(int f)
1174 {
1175         char b[2];
1176         readfd(f, b, 2);
1177         return (UVAL(b, 1) << 8) + UVAL(b, 0);
1178 }
1179
1180 int32 read_int(int f)
1181 {
1182         char b[4];
1183         int32 num;
1184
1185         readfd(f, b, 4);
1186         num = IVAL(b, 0);
1187 #if SIZEOF_INT32 > 4
1188         if (num & (int32)0x80000000)
1189                 num |= ~(int32)0xffffffff;
1190 #endif
1191         return num;
1192 }
1193
1194 int32 read_varint(int f)
1195 {
1196         union {
1197             char b[5];
1198             int32 x;
1199         } u;
1200         uchar ch;
1201         int extra;
1202
1203         u.x = 0;
1204         readfd(f, (char*)&ch, 1);
1205         extra = int_byte_extra[ch / 4];
1206         if (extra) {
1207                 uchar bit = ((uchar)1<<(8-extra));
1208                 if (extra >= (int)sizeof u.b) {
1209                         rprintf(FERROR, "Overflow in read_varint()\n");
1210                         exit_cleanup(RERR_STREAMIO);
1211                 }
1212                 readfd(f, u.b, extra);
1213                 u.b[extra] = ch & (bit-1);
1214         } else
1215                 u.b[0] = ch;
1216 #if CAREFUL_ALIGNMENT
1217         u.x = IVAL(u.b,0);
1218 #endif
1219 #if SIZEOF_INT32 > 4
1220         if (u.x & (int32)0x80000000)
1221                 u.x |= ~(int32)0xffffffff;
1222 #endif
1223         return u.x;
1224 }
1225
1226 int64 read_varlong(int f, uchar min_bytes)
1227 {
1228         union {
1229             char b[9];
1230             int64 x;
1231         } u;
1232         char b2[8];
1233         int extra;
1234
1235 #if SIZEOF_INT64 < 8
1236         memset(u.b, 0, 8);
1237 #else
1238         u.x = 0;
1239 #endif
1240         readfd(f, b2, min_bytes);
1241         memcpy(u.b, b2+1, min_bytes-1);
1242         extra = int_byte_extra[CVAL(b2, 0) / 4];
1243         if (extra) {
1244                 uchar bit = ((uchar)1<<(8-extra));
1245                 if (min_bytes + extra > (int)sizeof u.b) {
1246                         rprintf(FERROR, "Overflow in read_varlong()\n");
1247                         exit_cleanup(RERR_STREAMIO);
1248                 }
1249                 readfd(f, u.b + min_bytes - 1, extra);
1250                 u.b[min_bytes + extra - 1] = CVAL(b2, 0) & (bit-1);
1251 #if SIZEOF_INT64 < 8
1252                 if (min_bytes + extra > 5 || u.b[4] || CVAL(u.b,3) & 0x80) {
1253                         rprintf(FERROR, "Integer overflow: attempted 64-bit offset\n");
1254                         exit_cleanup(RERR_UNSUPPORTED);
1255                 }
1256 #endif
1257         } else
1258                 u.b[min_bytes + extra - 1] = CVAL(b2, 0);
1259 #if SIZEOF_INT64 < 8
1260         u.x = IVAL(u.b,0);
1261 #elif CAREFUL_ALIGNMENT
1262         u.x = IVAL(u.b,0) | (((int64)IVAL(u.b,4))<<32);
1263 #endif
1264         return u.x;
1265 }
1266
1267 int64 read_longint(int f)
1268 {
1269 #if SIZEOF_INT64 >= 8
1270         char b[9];
1271 #endif
1272         int32 num = read_int(f);
1273
1274         if (num != (int32)0xffffffff)
1275                 return num;
1276
1277 #if SIZEOF_INT64 < 8
1278         rprintf(FERROR, "Integer overflow: attempted 64-bit offset\n");
1279         exit_cleanup(RERR_UNSUPPORTED);
1280 #else
1281         readfd(f, b, 8);
1282         return IVAL(b,0) | (((int64)IVAL(b,4))<<32);
1283 #endif
1284 }
1285
1286 void read_buf(int f, char *buf, size_t len)
1287 {
1288         readfd(f,buf,len);
1289 }
1290
1291 void read_sbuf(int f, char *buf, size_t len)
1292 {
1293         readfd(f, buf, len);
1294         buf[len] = '\0';
1295 }
1296
1297 uchar read_byte(int f)
1298 {
1299         uchar c;
1300         readfd(f, (char *)&c, 1);
1301         return c;
1302 }
1303
1304 int read_vstring(int f, char *buf, int bufsize)
1305 {
1306         int len = read_byte(f);
1307
1308         if (len & 0x80)
1309                 len = (len & ~0x80) * 0x100 + read_byte(f);
1310
1311         if (len >= bufsize) {
1312                 rprintf(FERROR, "over-long vstring received (%d > %d)\n",
1313                         len, bufsize - 1);
1314                 return -1;
1315         }
1316
1317         if (len)
1318                 readfd(f, buf, len);
1319         buf[len] = '\0';
1320         return len;
1321 }
1322
1323 /* Populate a sum_struct with values from the socket.  This is
1324  * called by both the sender and the receiver. */
1325 void read_sum_head(int f, struct sum_struct *sum)
1326 {
1327         int32 max_blength = protocol_version < 30 ? OLD_MAX_BLOCK_SIZE : MAX_BLOCK_SIZE;
1328         sum->count = read_int(f);
1329         if (sum->count < 0) {
1330                 rprintf(FERROR, "Invalid checksum count %ld [%s]\n",
1331                         (long)sum->count, who_am_i());
1332                 exit_cleanup(RERR_PROTOCOL);
1333         }
1334         sum->blength = read_int(f);
1335         if (sum->blength < 0 || sum->blength > max_blength) {
1336                 rprintf(FERROR, "Invalid block length %ld [%s]\n",
1337                         (long)sum->blength, who_am_i());
1338                 exit_cleanup(RERR_PROTOCOL);
1339         }
1340         sum->s2length = protocol_version < 27 ? csum_length : (int)read_int(f);
1341         if (sum->s2length < 0 || sum->s2length > MAX_DIGEST_LEN) {
1342                 rprintf(FERROR, "Invalid checksum length %d [%s]\n",
1343                         sum->s2length, who_am_i());
1344                 exit_cleanup(RERR_PROTOCOL);
1345         }
1346         sum->remainder = read_int(f);
1347         if (sum->remainder < 0 || sum->remainder > sum->blength) {
1348                 rprintf(FERROR, "Invalid remainder length %ld [%s]\n",
1349                         (long)sum->remainder, who_am_i());
1350                 exit_cleanup(RERR_PROTOCOL);
1351         }
1352 }
1353
1354 /* Send the values from a sum_struct over the socket.  Set sum to
1355  * NULL if there are no checksums to send.  This is called by both
1356  * the generator and the sender. */
1357 void write_sum_head(int f, struct sum_struct *sum)
1358 {
1359         static struct sum_struct null_sum;
1360
1361         if (sum == NULL)
1362                 sum = &null_sum;
1363
1364         write_int(f, sum->count);
1365         write_int(f, sum->blength);
1366         if (protocol_version >= 27)
1367                 write_int(f, sum->s2length);
1368         write_int(f, sum->remainder);
1369 }
1370
1371 /**
1372  * Sleep after writing to limit I/O bandwidth usage.
1373  *
1374  * @todo Rather than sleeping after each write, it might be better to
1375  * use some kind of averaging.  The current algorithm seems to always
1376  * use a bit less bandwidth than specified, because it doesn't make up
1377  * for slow periods.  But arguably this is a feature.  In addition, we
1378  * ought to take the time used to write the data into account.
1379  *
1380  * During some phases of big transfers (file FOO is uptodate) this is
1381  * called with a small bytes_written every time.  As the kernel has to
1382  * round small waits up to guarantee that we actually wait at least the
1383  * requested number of microseconds, this can become grossly inaccurate.
1384  * We therefore keep track of the bytes we've written over time and only
1385  * sleep when the accumulated delay is at least 1 tenth of a second.
1386  **/
1387 static void sleep_for_bwlimit(int bytes_written)
1388 {
1389         static struct timeval prior_tv;
1390         static long total_written = 0;
1391         struct timeval tv, start_tv;
1392         long elapsed_usec, sleep_usec;
1393
1394 #define ONE_SEC 1000000L /* # of microseconds in a second */
1395
1396         if (!bwlimit_writemax)
1397                 return;
1398
1399         total_written += bytes_written;
1400
1401         gettimeofday(&start_tv, NULL);
1402         if (prior_tv.tv_sec) {
1403                 elapsed_usec = (start_tv.tv_sec - prior_tv.tv_sec) * ONE_SEC
1404                              + (start_tv.tv_usec - prior_tv.tv_usec);
1405                 total_written -= elapsed_usec * bwlimit / (ONE_SEC/1024);
1406                 if (total_written < 0)
1407                         total_written = 0;
1408         }
1409
1410         sleep_usec = total_written * (ONE_SEC/1024) / bwlimit;
1411         if (sleep_usec < ONE_SEC / 10) {
1412                 prior_tv = start_tv;
1413                 return;
1414         }
1415
1416         tv.tv_sec  = sleep_usec / ONE_SEC;
1417         tv.tv_usec = sleep_usec % ONE_SEC;
1418         select(0, NULL, NULL, NULL, &tv);
1419
1420         gettimeofday(&prior_tv, NULL);
1421         elapsed_usec = (prior_tv.tv_sec - start_tv.tv_sec) * ONE_SEC
1422                      + (prior_tv.tv_usec - start_tv.tv_usec);
1423         total_written = (sleep_usec - elapsed_usec) * bwlimit / (ONE_SEC/1024);
1424 }
1425
1426 static const char *what_fd_is(int fd)
1427 {
1428         static char buf[20];
1429
1430         if (fd == sock_f_out)
1431                 return "socket";
1432         else if (fd == msg_fd_out)
1433                 return "message fd";
1434         else if (fd == batch_fd)
1435                 return "batch file";
1436         else {
1437                 snprintf(buf, sizeof buf, "fd %d", fd);
1438                 return buf;
1439         }
1440 }
1441
1442 /* Write len bytes to the file descriptor fd, looping as necessary to get
1443  * the job done and also (in certain circumstances) reading any data on
1444  * msg_fd_in to avoid deadlock.
1445  *
1446  * This function underlies the multiplexing system.  The body of the
1447  * application never calls this function directly. */
1448 static void writefd_unbuffered(int fd, const char *buf, size_t len)
1449 {
1450         size_t n, total = 0;
1451         fd_set w_fds, r_fds, e_fds;
1452         int maxfd, count, cnt, using_r_fds;
1453         int defer_inc = 0;
1454         struct timeval tv;
1455
1456         if (no_flush++)
1457                 defer_forwarding_messages++, defer_inc++;
1458
1459         while (total < len) {
1460                 FD_ZERO(&w_fds);
1461                 FD_SET(fd, &w_fds);
1462                 FD_ZERO(&e_fds);
1463                 FD_SET(fd, &e_fds);
1464                 maxfd = fd;
1465
1466                 if (msg_fd_in >= 0) {
1467                         FD_ZERO(&r_fds);
1468                         FD_SET(msg_fd_in, &r_fds);
1469                         if (msg_fd_in > maxfd)
1470                                 maxfd = msg_fd_in;
1471                         using_r_fds = 1;
1472                 } else
1473                         using_r_fds = 0;
1474
1475                 tv.tv_sec = select_timeout;
1476                 tv.tv_usec = 0;
1477
1478                 errno = 0;
1479                 count = select(maxfd + 1, using_r_fds ? &r_fds : NULL,
1480                                &w_fds, &e_fds, &tv);
1481
1482                 if (count <= 0) {
1483                         if (count < 0 && errno == EBADF)
1484                                 exit_cleanup(RERR_SOCKETIO);
1485                         check_timeout();
1486                         continue;
1487                 }
1488
1489                 /*if (FD_ISSET(fd, &e_fds))
1490                         rprintf(FINFO, "select exception on fd %d\n", fd); */
1491
1492                 if (using_r_fds && FD_ISSET(msg_fd_in, &r_fds))
1493                         read_msg_fd();
1494
1495                 if (!FD_ISSET(fd, &w_fds))
1496                         continue;
1497
1498                 n = len - total;
1499                 if (bwlimit_writemax && n > bwlimit_writemax)
1500                         n = bwlimit_writemax;
1501                 cnt = write(fd, buf + total, n);
1502
1503                 if (cnt <= 0) {
1504                         if (cnt < 0) {
1505                                 if (errno == EINTR)
1506                                         continue;
1507                                 if (errno == EWOULDBLOCK || errno == EAGAIN) {
1508                                         msleep(1);
1509                                         continue;
1510                                 }
1511                         }
1512
1513                         /* Don't try to write errors back across the stream. */
1514                         if (fd == sock_f_out)
1515                                 io_end_multiplex_out();
1516                         /* Don't try to write errors down a failing msg pipe. */
1517                         if (am_server && fd == msg_fd_out)
1518                                 exit_cleanup(RERR_STREAMIO);
1519                         rsyserr(FERROR, errno,
1520                                 "writefd_unbuffered failed to write %ld bytes to %s [%s]",
1521                                 (long)len, what_fd_is(fd), who_am_i());
1522                         /* If the other side is sending us error messages, try
1523                          * to grab any messages they sent before they died. */
1524                         while (!am_server && fd == sock_f_out && io_multiplexing_in) {
1525                                 char buf[1024];
1526                                 set_io_timeout(30);
1527                                 ignore_timeout = 0;
1528                                 readfd_unbuffered(sock_f_in, buf, sizeof buf);
1529                         }
1530                         exit_cleanup(RERR_STREAMIO);
1531                 }
1532
1533                 total += cnt;
1534                 defer_forwarding_messages++, defer_inc++;
1535
1536                 if (fd == sock_f_out) {
1537                         if (io_timeout || am_generator)
1538                                 last_io_out = time(NULL);
1539                         sleep_for_bwlimit(cnt);
1540                 }
1541         }
1542
1543         no_flush--;
1544         if (keep_defer_forwarding)
1545                 defer_inc--;
1546         if (!(defer_forwarding_messages -= defer_inc) && !no_flush)
1547                 msg_flush();
1548 }
1549
1550 int io_flush(int flush_it_all)
1551 {
1552         int flushed_something = 0;
1553
1554         if (no_flush)
1555                 return 0;
1556
1557         if (iobuf_out_cnt) {
1558                 if (io_multiplexing_out)
1559                         mplex_write(sock_f_out, MSG_DATA, iobuf_out, iobuf_out_cnt, 0);
1560                 else
1561                         writefd_unbuffered(iobuf_f_out, iobuf_out, iobuf_out_cnt);
1562                 iobuf_out_cnt = 0;
1563                 flushed_something = 1;
1564         }
1565
1566         if (flush_it_all && !defer_forwarding_messages && msg_queue.head) {
1567                 msg_flush();
1568                 flushed_something = 1;
1569         }
1570
1571         return flushed_something;
1572 }
1573
1574 static void writefd(int fd, const char *buf, size_t len)
1575 {
1576         if (fd == sock_f_out)
1577                 stats.total_written += len;
1578
1579         if (fd == write_batch_monitor_out)
1580                 writefd_unbuffered(batch_fd, buf, len);
1581
1582         if (!iobuf_out || fd != iobuf_f_out) {
1583                 writefd_unbuffered(fd, buf, len);
1584                 return;
1585         }
1586
1587         while (len) {
1588                 int n = MIN((int)len, IO_BUFFER_SIZE - iobuf_out_cnt);
1589                 if (n > 0) {
1590                         memcpy(iobuf_out+iobuf_out_cnt, buf, n);
1591                         buf += n;
1592                         len -= n;
1593                         iobuf_out_cnt += n;
1594                 }
1595
1596                 if (iobuf_out_cnt == IO_BUFFER_SIZE)
1597                         io_flush(NORMAL_FLUSH);
1598         }
1599 }
1600
1601 void write_shortint(int f, unsigned short x)
1602 {
1603         char b[2];
1604         b[0] = (char)x;
1605         b[1] = (char)(x >> 8);
1606         writefd(f, b, 2);
1607 }
1608
1609 void write_int(int f, int32 x)
1610 {
1611         char b[4];
1612         SIVAL(b, 0, x);
1613         writefd(f, b, 4);
1614 }
1615
1616 void write_varint(int f, int32 x)
1617 {
1618         char b[5];
1619         uchar bit;
1620         int cnt = 4;
1621
1622         SIVAL(b, 1, x);
1623
1624         while (cnt > 1 && b[cnt] == 0)
1625                 cnt--;
1626         bit = ((uchar)1<<(7-cnt+1));
1627         if (CVAL(b, cnt) >= bit) {
1628                 cnt++;
1629                 *b = ~(bit-1);
1630         } else if (cnt > 1)
1631                 *b = b[cnt] | ~(bit*2-1);
1632         else
1633                 *b = b[cnt];
1634
1635         writefd(f, b, cnt);
1636 }
1637
1638 void write_varlong(int f, int64 x, uchar min_bytes)
1639 {
1640         char b[9];
1641         uchar bit;
1642         int cnt = 8;
1643
1644         SIVAL(b, 1, x);
1645 #if SIZEOF_INT64 >= 8
1646         SIVAL(b, 5, x >> 32);
1647 #else
1648         if (x <= 0x7FFFFFFF && x >= 0)
1649                 memset(b + 5, 0, 4);
1650         else {
1651                 rprintf(FERROR, "Integer overflow: attempted 64-bit offset\n");
1652                 exit_cleanup(RERR_UNSUPPORTED);
1653         }
1654 #endif
1655
1656         while (cnt > min_bytes && b[cnt] == 0)
1657                 cnt--;
1658         bit = ((uchar)1<<(7-cnt+min_bytes));
1659         if (CVAL(b, cnt) >= bit) {
1660                 cnt++;
1661                 *b = ~(bit-1);
1662         } else if (cnt > min_bytes)
1663                 *b = b[cnt] | ~(bit*2-1);
1664         else
1665                 *b = b[cnt];
1666
1667         writefd(f, b, cnt);
1668 }
1669
1670 /*
1671  * Note: int64 may actually be a 32-bit type if ./configure couldn't find any
1672  * 64-bit types on this platform.
1673  */
1674 void write_longint(int f, int64 x)
1675 {
1676         char b[12], * const s = b+4;
1677
1678         SIVAL(s, 0, x);
1679         if (x <= 0x7FFFFFFF && x >= 0) {
1680                 writefd(f, s, 4);
1681                 return;
1682         }
1683
1684 #if SIZEOF_INT64 < 8
1685         rprintf(FERROR, "Integer overflow: attempted 64-bit offset\n");
1686         exit_cleanup(RERR_UNSUPPORTED);
1687 #else
1688         memset(b, 0xFF, 4);
1689         SIVAL(s, 4, x >> 32);
1690         writefd(f, b, 12);
1691 #endif
1692 }
1693
1694 void write_buf(int f, const char *buf, size_t len)
1695 {
1696         writefd(f,buf,len);
1697 }
1698
1699 /** Write a string to the connection */
1700 void write_sbuf(int f, const char *buf)
1701 {
1702         writefd(f, buf, strlen(buf));
1703 }
1704
1705 void write_byte(int f, uchar c)
1706 {
1707         writefd(f, (char *)&c, 1);
1708 }
1709
1710 void write_vstring(int f, const char *str, int len)
1711 {
1712         uchar lenbuf[3], *lb = lenbuf;
1713
1714         if (len > 0x7F) {
1715                 if (len > 0x7FFF) {
1716                         rprintf(FERROR,
1717                                 "attempting to send over-long vstring (%d > %d)\n",
1718                                 len, 0x7FFF);
1719                         exit_cleanup(RERR_PROTOCOL);
1720                 }
1721                 *lb++ = len / 0x100 + 0x80;
1722         }
1723         *lb = len;
1724
1725         writefd(f, (char*)lenbuf, lb - lenbuf + 1);
1726         if (len)
1727                 writefd(f, str, len);
1728 }
1729
1730 /* Send a file-list index using a byte-reduction method. */
1731 void write_ndx(int f, int32 ndx)
1732 {
1733         static int32 prev_positive = -1, prev_negative = 1;
1734         int32 diff, cnt = 0;
1735         char b[6];
1736
1737         if (protocol_version < 30 || read_batch) {
1738                 write_int(f, ndx);
1739                 return;
1740         }
1741
1742         /* Send NDX_DONE as a single-byte 0 with no side effects.  Send
1743          * negative nums as a positive after sending a leading 0xFF. */
1744         if (ndx >= 0) {
1745                 diff = ndx - prev_positive;
1746                 prev_positive = ndx;
1747         } else if (ndx == NDX_DONE) {
1748                 *b = 0;
1749                 writefd(f, b, 1);
1750                 return;
1751         } else {
1752                 b[cnt++] = (char)0xFF;
1753                 ndx = -ndx;
1754                 diff = ndx - prev_negative;
1755                 prev_negative = ndx;
1756         }
1757
1758         /* A diff of 1 - 253 is sent as a one-byte diff; a diff of 254 - 32767
1759          * or 0 is sent as a 0xFE + a two-byte diff; otherwise we send 0xFE
1760          * & all 4 bytes of the (non-negative) num with the high-bit set. */
1761         if (diff < 0xFE && diff > 0)
1762                 b[cnt++] = (char)diff;
1763         else if (diff < 0 || diff > 0x7FFF) {
1764                 b[cnt++] = (char)0xFE;
1765                 b[cnt++] = (char)((ndx >> 24) | 0x80);
1766                 b[cnt++] = (char)ndx;
1767                 b[cnt++] = (char)(ndx >> 8);
1768                 b[cnt++] = (char)(ndx >> 16);
1769         } else {
1770                 b[cnt++] = (char)0xFE;
1771                 b[cnt++] = (char)(diff >> 8);
1772                 b[cnt++] = (char)diff;
1773         }
1774         writefd(f, b, cnt);
1775 }
1776
1777 /* Receive a file-list index using a byte-reduction method. */
1778 int32 read_ndx(int f)
1779 {
1780         static int32 prev_positive = -1, prev_negative = 1;
1781         int32 *prev_ptr, num;
1782         char b[4];
1783
1784         if (protocol_version < 30)
1785                 return read_int(f);
1786
1787         readfd(f, b, 1);
1788         if (CVAL(b, 0) == 0xFF) {
1789                 readfd(f, b, 1);
1790                 prev_ptr = &prev_negative;
1791         } else if (CVAL(b, 0) == 0)
1792                 return NDX_DONE;
1793         else
1794                 prev_ptr = &prev_positive;
1795         if (CVAL(b, 0) == 0xFE) {
1796                 readfd(f, b, 2);
1797                 if (CVAL(b, 0) & 0x80) {
1798                         b[3] = CVAL(b, 0) & ~0x80;
1799                         b[0] = b[1];
1800                         readfd(f, b+1, 2);
1801                         num = IVAL(b, 0);
1802                 } else
1803                         num = (UVAL(b,0)<<8) + UVAL(b,1) + *prev_ptr;
1804         } else
1805                 num = UVAL(b, 0) + *prev_ptr;
1806         *prev_ptr = num;
1807         if (prev_ptr == &prev_negative)
1808                 num = -num;
1809         return num;
1810 }
1811
1812 /* Read a line of up to bufsiz-1 characters into buf.  Strips
1813  * the (required) trailing newline and all carriage returns.
1814  * Returns 1 for success; 0 for I/O error or truncation. */
1815 int read_line_old(int f, char *buf, size_t bufsiz)
1816 {
1817         bufsiz--; /* leave room for the null */
1818         while (bufsiz > 0) {
1819                 buf[0] = 0;
1820                 read_buf(f, buf, 1);
1821                 if (buf[0] == 0)
1822                         return 0;
1823                 if (buf[0] == '\n')
1824                         break;
1825                 if (buf[0] != '\r') {
1826                         buf++;
1827                         bufsiz--;
1828                 }
1829         }
1830         *buf = '\0';
1831         return bufsiz > 0;
1832 }
1833
1834 void io_printf(int fd, const char *format, ...)
1835 {
1836         va_list ap;
1837         char buf[BIGPATHBUFLEN];
1838         int len;
1839
1840         va_start(ap, format);
1841         len = vsnprintf(buf, sizeof buf, format, ap);
1842         va_end(ap);
1843
1844         if (len < 0)
1845                 exit_cleanup(RERR_STREAMIO);
1846
1847         if (len > (int)sizeof buf) {
1848                 rprintf(FERROR, "io_printf() was too long for the buffer.\n");
1849                 exit_cleanup(RERR_STREAMIO);
1850         }
1851
1852         write_sbuf(fd, buf);
1853 }
1854
1855 /** Setup for multiplexing a MSG_* stream with the data stream. */
1856 void io_start_multiplex_out(void)
1857 {
1858         io_flush(NORMAL_FLUSH);
1859         io_start_buffering_out(sock_f_out);
1860         io_multiplexing_out = 1;
1861 }
1862
1863 /** Setup for multiplexing a MSG_* stream with the data stream. */
1864 void io_start_multiplex_in(void)
1865 {
1866         io_flush(NORMAL_FLUSH);
1867         io_start_buffering_in(sock_f_in);
1868         io_multiplexing_in = 1;
1869 }
1870
1871 /** Write an message to the multiplexed data stream. */
1872 int io_multiplex_write(enum msgcode code, const char *buf, size_t len, int convert)
1873 {
1874         if (!io_multiplexing_out)
1875                 return 0;
1876         io_flush(NORMAL_FLUSH);
1877         stats.total_written += (len+4);
1878         mplex_write(sock_f_out, code, buf, len, convert);
1879         return 1;
1880 }
1881
1882 void io_end_multiplex_in(void)
1883 {
1884         io_multiplexing_in = 0;
1885         io_end_buffering_in();
1886 }
1887
1888 /** Stop output multiplexing. */
1889 void io_end_multiplex_out(void)
1890 {
1891         io_multiplexing_out = 0;
1892         io_end_buffering_out();
1893 }
1894
1895 void start_write_batch(int fd)
1896 {
1897         /* Some communication has already taken place, but we don't
1898          * enable batch writing until here so that we can write a
1899          * canonical record of the communication even though the
1900          * actual communication so far depends on whether a daemon
1901          * is involved. */
1902         write_int(batch_fd, protocol_version);
1903         if (protocol_version >= 30)
1904                 write_byte(batch_fd, inc_recurse);
1905         write_int(batch_fd, checksum_seed);
1906
1907         if (am_sender)
1908                 write_batch_monitor_out = fd;
1909         else
1910                 write_batch_monitor_in = fd;
1911 }
1912
1913 void stop_write_batch(void)
1914 {
1915         write_batch_monitor_out = -1;
1916         write_batch_monitor_in = -1;
1917 }