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