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