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