io.c

   1 /*
   2    Copyright (C) Andrew Tridgell 1996
   3    Copyright (C) Paul Mackerras 1996
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software
  17    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20 /*
  21   Utilities used in rsync
  22
  23   tridge, June 1996
  24   */
  25 #include "rsync.h"
  26
  27 /* if no timeout is specified then use a 60 second select timeout */
  28 #define SELECT_TIMEOUT 60
  29
  30 static int io_multiplexing_out;
  31 static int io_multiplexing_in;
  32 static int multiplex_in_fd;
  33 static int multiplex_out_fd;
  34 static time_t last_io;
  35 static int eof_error=1;
  36 extern int verbose;
  37 extern int io_timeout;
  38 extern struct stats stats;
  39
  40 static int buffer_f_in = -1;
  41
  42 void setup_readbuffer(int f_in)
  43 {
  44         buffer_f_in = f_in;
  45 }
  46
  47 static void check_timeout(void)
  48 {
  49         time_t t;
  50
  51         if (!io_timeout) return;
  52
  53         if (!last_io) {
  54                 last_io = time(NULL);
  55                 return;
  56         }
  57
  58         t = time(NULL);
  59
  60         if (last_io && io_timeout && (t-last_io) >= io_timeout) {
  61                 rprintf(FERROR,"io timeout after %d second - exiting\n",
  62                         (int)(t-last_io));
  63                 exit_cleanup(RERR_TIMEOUT);
  64         }
  65 }
  66
  67
  68 static char *read_buffer;
  69 static char *read_buffer_p;
  70 static int read_buffer_len;
  71 static int read_buffer_size;
  72 static int no_flush;
  73 static int no_flush_read;
  74
  75 /* read from a socket with IO timeout. return the number of
  76    bytes read. If no bytes can be read then exit, never return
  77    a number <= 0 */
  78 static int read_timeout(int fd, char *buf, int len)
  79 {
  80         int n, ret=0;
  81
  82         no_flush_read++;
  83         io_flush();
  84         no_flush_read--;
  85
  86         while (ret == 0) {
  87                 fd_set fds;
  88                 struct timeval tv;
  89
  90                 FD_ZERO(&fds);
  91                 FD_SET(fd, &fds);
  92                 tv.tv_sec = io_timeout?io_timeout:SELECT_TIMEOUT;
  93                 tv.tv_usec = 0;
  94
  95                 if (select(fd+1, &fds, NULL, NULL, &tv) != 1) {
  96                         check_timeout();
  97                         continue;
  98                 }
  99
 100                 n = read(fd, buf, len);
 101
 102                 if (n > 0) {
 103                         buf += n;
 104                         len -= n;
 105                         ret += n;
 106                         if (io_timeout)
 107                                 last_io = time(NULL);
 108                         continue;
 109                 }
 110
 111                 if (n == -1 && errno == EINTR) {
 112                         continue;
 113                 }
 114
 115                 if (n == 0) {
 116                         if (eof_error) {
 117                                 rprintf(FERROR,"unexpected EOF in read_timeout\n");
 118                         }
 119                         exit_cleanup(RERR_STREAMIO);
 120                 }
 121
 122                 rprintf(FERROR,"read error: %s\n", strerror(errno));
 123                 exit_cleanup(RERR_STREAMIO);
 124         }
 125
 126         return ret;
 127 }
 128
 129 /* continue trying to read len bytes - don't return until len
 130    has been read */
 131 static void read_loop(int fd, char *buf, int len)
 132 {
 133         while (len) {
 134                 int n = read_timeout(fd, buf, len);
 135
 136                 buf += n;
 137                 len -= n;
 138         }
 139 }
 140
 141 /* read from the file descriptor handling multiplexing -
 142    return number of bytes read
 143    never return <= 0 */
 144 static int read_unbuffered(int fd, char *buf, int len)
 145 {
 146         static int remaining;
 147         char ibuf[4];
 148         int tag, ret=0;
 149         char line[1024];
 150
 151         if (!io_multiplexing_in || fd != multiplex_in_fd)
 152                 return read_timeout(fd, buf, len);
 153
 154         while (ret == 0) {
 155                 if (remaining) {
 156                         len = MIN(len, remaining);
 157                         read_loop(fd, buf, len);
 158                         remaining -= len;
 159                         ret = len;
 160                         continue;
 161                 }
 162
 163                 read_loop(fd, ibuf, 4);
 164                 tag = IVAL(ibuf, 0);
 165
 166                 remaining = tag & 0xFFFFFF;
 167                 tag = tag >> 24;
 168
 169                 if (tag == MPLEX_BASE) continue;
 170
 171                 tag -= MPLEX_BASE;
 172
 173                 if (tag != FERROR && tag != FINFO) {
 174                         rprintf(FERROR,"unexpected tag %d\n", tag);
 175                         exit_cleanup(RERR_STREAMIO);
 176                 }
 177
 178                 if (remaining > sizeof(line)-1) {
 179                         rprintf(FERROR,"multiplexing overflow %d\n\n",
 180                                 remaining);
 181                         exit_cleanup(RERR_STREAMIO);
 182                 }
 183
 184                 read_loop(fd, line, remaining);
 185                 line[remaining] = 0;
 186
 187                 rprintf(tag,"%s", line);
 188                 remaining = 0;
 189         }
 190
 191         return ret;
 192 }
 193
 194
 195
 196 /* This function was added to overcome a deadlock problem when using
 197  * ssh.  It looks like we can't allow our receive queue to get full or
 198  * ssh will clag up. Uggh.  */
 199 static void read_check(int f)
 200 {
 201         int n = 8192;
 202
 203         if (f == -1) return;
 204
 205         if (read_buffer_len == 0) {
 206                 read_buffer_p = read_buffer;
 207         }
 208
 209         if (n > MAX_READ_BUFFER/4)
 210                 n = MAX_READ_BUFFER/4;
 211
 212         if (read_buffer_p != read_buffer) {
 213                 memmove(read_buffer,read_buffer_p,read_buffer_len);
 214                 read_buffer_p = read_buffer;
 215         }
 216
 217         if (n > (read_buffer_size - read_buffer_len)) {
 218                 read_buffer_size += n;
 219                 read_buffer = (char *)Realloc(read_buffer,read_buffer_size);
 220                 if (!read_buffer) out_of_memory("read check");
 221                 read_buffer_p = read_buffer;
 222         }
 223
 224         n = read_unbuffered(f,read_buffer+read_buffer_len,n);
 225         read_buffer_len += n;
 226 }
 227
 228
 229 /* do a buffered read from fd. don't return until all N bytes
 230    have been read. If all N can't be read then exit with an error */
 231 static void readfd(int fd,char *buffer,int N)
 232 {
 233         int  ret;
 234         int total=0;
 235
 236         if ((read_buffer_len < N) && (N < 1024)) {
 237                 read_check(buffer_f_in);
 238         }
 239
 240         while (total < N) {
 241                 if (read_buffer_len > 0 && buffer_f_in == fd) {
 242                         ret = MIN(read_buffer_len,N-total);
 243                         memcpy(buffer+total,read_buffer_p,ret);
 244                         read_buffer_p += ret;
 245                         read_buffer_len -= ret;
 246                         total += ret;
 247                         continue;
 248                 }
 249
 250                 no_flush_read++;
 251                 io_flush();
 252                 no_flush_read--;
 253
 254                 ret = read_unbuffered(fd,buffer + total,N-total);
 255                 total += ret;
 256         }
 257
 258         stats.total_read += total;
 259 }
 260
 261
 262 int32 read_int(int f)
 263 {
 264         char b[4];
 265         int32 ret;
 266
 267         readfd(f,b,4);
 268         ret = IVAL(b,0);
 269         if (ret == (int32)0xffffffff) return -1;
 270         return ret;
 271 }
 272
 273 int64 read_longint(int f)
 274 {
 275         extern int remote_version;
 276         int64 ret;
 277         char b[8];
 278         ret = read_int(f);
 279
 280         if ((int32)ret != (int32)0xffffffff) {
 281                 return ret;
 282         }
 283
 284 #ifdef NO_INT64
 285         rprintf(FERROR,"Integer overflow - attempted 64 bit offset\n");
 286         exit_cleanup(RERR_UNSUPPORTED);
 287 #else
 288         if (remote_version >= 16) {
 289                 readfd(f,b,8);
 290                 ret = IVAL(b,0) | (((int64)IVAL(b,4))<<32);
 291         }
 292 #endif
 293
 294         return ret;
 295 }
 296
 297 void read_buf(int f,char *buf,int len)
 298 {
 299         readfd(f,buf,len);
 300 }
 301
 302 void read_sbuf(int f,char *buf,int len)
 303 {
 304         read_buf(f,buf,len);
 305         buf[len] = 0;
 306 }
 307
 308 unsigned char read_byte(int f)
 309 {
 310         unsigned char c;
 311         read_buf(f,(char *)&c,1);
 312         return c;
 313 }
 314
 315
 316
 317 /* write len bytes to fd, possibly reading from buffer_f_in if set
 318    in order to unclog the pipe. don't return until all len
 319    bytes have been written */
 320 static void writefd_unbuffered(int fd,char *buf,int len)
 321 {
 322         int total = 0;
 323         fd_set w_fds, r_fds;
 324         int fd_count, count;
 325         struct timeval tv;
 326         int reading=0;
 327
 328         no_flush++;
 329
 330         while (total < len) {
 331                 FD_ZERO(&w_fds);
 332                 FD_ZERO(&r_fds);
 333                 FD_SET(fd,&w_fds);
 334                 fd_count = fd+1;
 335
 336                 if (!no_flush_read) {
 337                         reading = (buffer_f_in != -1);
 338                 }
 339
 340                 if (reading) {
 341                         FD_SET(buffer_f_in,&r_fds);
 342                         if (buffer_f_in > fd)
 343                                 fd_count = buffer_f_in+1;
 344                 }
 345
 346                 tv.tv_sec = io_timeout?io_timeout:SELECT_TIMEOUT;
 347                 tv.tv_usec = 0;
 348
 349                 count = select(fd_count,
 350                                reading?&r_fds:NULL,
 351                                &w_fds,NULL,
 352                                &tv);
 353
 354                 if (count <= 0) {
 355                         check_timeout();
 356                         continue;
 357                 }
 358
 359                 if (reading && FD_ISSET(buffer_f_in, &r_fds)) {
 360                         read_check(buffer_f_in);
 361                 }
 362
 363                 if (FD_ISSET(fd, &w_fds)) {
 364                         int n = len-total;
 365                         int ret = write(fd,buf+total,n?n:1);
 366
 367                         if (ret == -1 && errno == EINTR) {
 368                                 continue;
 369                         }
 370
 371                         if (ret <= 0) {
 372                                 rprintf(FERROR,"erroring writing %d bytes - exiting\n", len);
 373                                 exit_cleanup(RERR_STREAMIO);
 374                         }
 375
 376                         total += ret;
 377
 378                         if (io_timeout)
 379                                 last_io = time(NULL);
 380                 }
 381         }
 382
 383         no_flush--;
 384 }
 385
 386
 387 static char *io_buffer;
 388 static int io_buffer_count;
 389
 390 void io_start_buffering(int fd)
 391 {
 392         if (io_buffer) return;
 393         multiplex_out_fd = fd;
 394         io_buffer = (char *)malloc(IO_BUFFER_SIZE+4);
 395         if (!io_buffer) out_of_memory("writefd");
 396         io_buffer_count = 0;
 397
 398         /* leave room for the multiplex header in case it's needed */
 399         io_buffer += 4;
 400 }
 401
 402 void io_flush(void)
 403 {
 404         int fd = multiplex_out_fd;
 405         if (!io_buffer_count || no_flush) return;
 406
 407         if (io_multiplexing_out) {
 408                 SIVAL(io_buffer-4, 0, (MPLEX_BASE<<24) + io_buffer_count);
 409                 writefd_unbuffered(fd, io_buffer-4, io_buffer_count+4);
 410         } else {
 411                 writefd_unbuffered(fd, io_buffer, io_buffer_count);
 412         }
 413         io_buffer_count = 0;
 414 }
 415
 416 void io_end_buffering(int fd)
 417 {
 418         io_flush();
 419         if (!io_multiplexing_out) {
 420                 free(io_buffer-4);
 421                 io_buffer = NULL;
 422         }
 423 }
 424
 425 static void writefd(int fd,char *buf,int len)
 426 {
 427         stats.total_written += len;
 428
 429         if (!io_buffer) {
 430                 writefd_unbuffered(fd, buf, len);
 431                 return;
 432         }
 433
 434         while (len) {
 435                 int n = MIN(len, IO_BUFFER_SIZE-io_buffer_count);
 436                 if (n > 0) {
 437                         memcpy(io_buffer+io_buffer_count, buf, n);
 438                         buf += n;
 439                         len -= n;
 440                         io_buffer_count += n;
 441                 }
 442
 443                 if (io_buffer_count == IO_BUFFER_SIZE) io_flush();
 444         }
 445 }
 446
 447
 448 void write_int(int f,int32 x)
 449 {
 450         char b[4];
 451         SIVAL(b,0,x);
 452         writefd(f,b,4);
 453 }
 454
 455 void write_longint(int f, int64 x)
 456 {
 457         extern int remote_version;
 458         char b[8];
 459
 460         if (remote_version < 16 || x <= 0x7FFFFFFF) {
 461                 write_int(f, (int)x);
 462                 return;
 463         }
 464
 465         write_int(f, (int32)0xFFFFFFFF);
 466         SIVAL(b,0,(x&0xFFFFFFFF));
 467         SIVAL(b,4,((x>>32)&0xFFFFFFFF));
 468
 469         writefd(f,b,8);
 470 }
 471
 472 void write_buf(int f,char *buf,int len)
 473 {
 474         writefd(f,buf,len);
 475 }
 476
 477 /* write a string to the connection */
 478 static void write_sbuf(int f,char *buf)
 479 {
 480         write_buf(f, buf, strlen(buf));
 481 }
 482
 483
 484 void write_byte(int f,unsigned char c)
 485 {
 486         write_buf(f,(char *)&c,1);
 487 }
 488
 489 int read_line(int f, char *buf, int maxlen)
 490 {
 491         eof_error = 0;
 492
 493         while (maxlen) {
 494                 buf[0] = 0;
 495                 read_buf(f, buf, 1);
 496                 if (buf[0] == 0) return 0;
 497                 if (buf[0] == '\n') {
 498                         buf[0] = 0;
 499                         break;
 500                 }
 501                 if (buf[0] != '\r') {
 502                         buf++;
 503                         maxlen--;
 504                 }
 505         }
 506         if (maxlen == 0) {
 507                 *buf = 0;
 508                 return 0;
 509         }
 510
 511         eof_error = 1;
 512
 513         return 1;
 514 }
 515
 516
 517 void io_printf(int fd, const char *format, ...)
 518 {
 519         va_list ap;
 520         char buf[1024];
 521         int len;
 522
 523         va_start(ap, format);
 524         len = vslprintf(buf, sizeof(buf), format, ap);
 525         va_end(ap);
 526
 527         if (len < 0) exit_cleanup(RERR_STREAMIO);
 528
 529         write_sbuf(fd, buf);
 530 }
 531
 532
 533 /* setup for multiplexing an error stream with the data stream */
 534 void io_start_multiplex_out(int fd)
 535 {
 536         multiplex_out_fd = fd;
 537         io_flush();
 538         io_start_buffering(fd);
 539         io_multiplexing_out = 1;
 540 }
 541
 542 /* setup for multiplexing an error stream with the data stream */
 543 void io_start_multiplex_in(int fd)
 544 {
 545         multiplex_in_fd = fd;
 546         io_flush();
 547         if (read_buffer_len) {
 548                 fprintf(stderr,"ERROR: data in read buffer at mplx start\n");
 549                 exit_cleanup(RERR_STREAMIO);
 550         }
 551
 552         io_multiplexing_in = 1;
 553 }
 554
 555 /* write an message to the error stream */
 556 int io_multiplex_write(int f, char *buf, int len)
 557 {
 558         if (!io_multiplexing_out) return 0;
 559
 560         io_flush();
 561
 562         SIVAL(io_buffer-4, 0, ((MPLEX_BASE + f)<<24) + len);
 563         memcpy(io_buffer, buf, len);
 564
 565         stats.total_written += (len+4);
 566
 567         writefd_unbuffered(multiplex_out_fd, io_buffer-4, len+4);
 568         return 1;
 569 }
 570
 571 void io_close_input(int fd)
 572 {
 573         buffer_f_in = -1;
 574 }