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
 116                 if (n == 0) {
 117                         if (eof_error) {
 118                                 rprintf(FERROR,"unexpected EOF in read_timeout\n");
 119                         }
 120                         exit_cleanup(RERR_STREAMIO);
 121                 }
 122
 123                 /* this prevents us trying to write errors on a dead socket */
 124                 io_multiplexing_out = 0;
 125
 126                 rprintf(FERROR,"read error: %s\n", strerror(errno));
 127                 exit_cleanup(RERR_STREAMIO);
 128         }
 129
 130         return ret;
 131 }
 132
 133 /* continue trying to read len bytes - don't return until len
 134    has been read */
 135 static void read_loop(int fd, char *buf, int len)
 136 {
 137         while (len) {
 138                 int n = read_timeout(fd, buf, len);
 139
 140                 buf += n;
 141                 len -= n;
 142         }
 143 }
 144
 145 /* read from the file descriptor handling multiplexing -
 146    return number of bytes read
 147    never return <= 0 */
 148 static int read_unbuffered(int fd, char *buf, int len)
 149 {
 150         static int remaining;
 151         char ibuf[4];
 152         int tag, ret=0;
 153         char line[1024];
 154
 155         if (!io_multiplexing_in || fd != multiplex_in_fd)
 156                 return read_timeout(fd, buf, len);
 157
 158         while (ret == 0) {
 159                 if (remaining) {
 160                         len = MIN(len, remaining);
 161                         read_loop(fd, buf, len);
 162                         remaining -= len;
 163                         ret = len;
 164                         continue;
 165                 }
 166
 167                 read_loop(fd, ibuf, 4);
 168                 tag = IVAL(ibuf, 0);
 169
 170                 remaining = tag & 0xFFFFFF;
 171                 tag = tag >> 24;
 172
 173                 if (tag == MPLEX_BASE) continue;
 174
 175                 tag -= MPLEX_BASE;
 176
 177                 if (tag != FERROR && tag != FINFO) {
 178                         rprintf(FERROR,"unexpected tag %d\n", tag);
 179                         exit_cleanup(RERR_STREAMIO);
 180                 }
 181
 182                 if (remaining > sizeof(line)-1) {
 183                         rprintf(FERROR,"multiplexing overflow %d\n\n",
 184                                 remaining);
 185                         exit_cleanup(RERR_STREAMIO);
 186                 }
 187
 188                 read_loop(fd, line, remaining);
 189                 line[remaining] = 0;
 190
 191                 rprintf(tag,"%s", line);
 192                 remaining = 0;
 193         }
 194
 195         return ret;
 196 }
 197
 198
 199
 200 /* This function was added to overcome a deadlock problem when using
 201  * ssh.  It looks like we can't allow our receive queue to get full or
 202  * ssh will clag up. Uggh.  */
 203 static void read_check(int f)
 204 {
 205         int n = 8192;
 206
 207         if (f == -1) return;
 208
 209         if (read_buffer_len == 0) {
 210                 read_buffer_p = read_buffer;
 211         }
 212
 213         if (n > MAX_READ_BUFFER/4)
 214                 n = MAX_READ_BUFFER/4;
 215
 216         if (read_buffer_p != read_buffer) {
 217                 memmove(read_buffer,read_buffer_p,read_buffer_len);
 218                 read_buffer_p = read_buffer;
 219         }
 220
 221         if (n > (read_buffer_size - read_buffer_len)) {
 222                 read_buffer_size += n;
 223                 read_buffer = (char *)Realloc(read_buffer,read_buffer_size);
 224                 if (!read_buffer) out_of_memory("read check");
 225                 read_buffer_p = read_buffer;
 226         }
 227
 228         n = read_unbuffered(f,read_buffer+read_buffer_len,n);
 229         read_buffer_len += n;
 230 }
 231
 232
 233 /* do a buffered read from fd. don't return until all N bytes
 234    have been read. If all N can't be read then exit with an error */
 235 static void readfd(int fd,char *buffer,int N)
 236 {
 237         int  ret;
 238         int total=0;
 239
 240         if ((read_buffer_len < N) && (N < 1024)) {
 241                 read_check(buffer_f_in);
 242         }
 243
 244         while (total < N) {
 245                 if (read_buffer_len > 0 && buffer_f_in == fd) {
 246                         ret = MIN(read_buffer_len,N-total);
 247                         memcpy(buffer+total,read_buffer_p,ret);
 248                         read_buffer_p += ret;
 249                         read_buffer_len -= ret;
 250                         total += ret;
 251                         continue;
 252                 }
 253
 254                 no_flush_read++;
 255                 io_flush();
 256                 no_flush_read--;
 257
 258                 ret = read_unbuffered(fd,buffer + total,N-total);
 259                 total += ret;
 260         }
 261
 262         stats.total_read += total;
 263 }
 264
 265
 266 int32 read_int(int f)
 267 {
 268         char b[4];
 269         int32 ret;
 270
 271         readfd(f,b,4);
 272         ret = IVAL(b,0);
 273         if (ret == (int32)0xffffffff) return -1;
 274         return ret;
 275 }
 276
 277 int64 read_longint(int f)
 278 {
 279         extern int remote_version;
 280         int64 ret;
 281         char b[8];
 282         ret = read_int(f);
 283
 284         if ((int32)ret != (int32)0xffffffff) {
 285                 return ret;
 286         }
 287
 288 #ifdef NO_INT64
 289         rprintf(FERROR,"Integer overflow - attempted 64 bit offset\n");
 290         exit_cleanup(RERR_UNSUPPORTED);
 291 #else
 292         if (remote_version >= 16) {
 293                 readfd(f,b,8);
 294                 ret = IVAL(b,0) | (((int64)IVAL(b,4))<<32);
 295         }
 296 #endif
 297
 298         return ret;
 299 }
 300
 301 void read_buf(int f,char *buf,int len)
 302 {
 303         readfd(f,buf,len);
 304 }
 305
 306 void read_sbuf(int f,char *buf,int len)
 307 {
 308         read_buf(f,buf,len);
 309         buf[len] = 0;
 310 }
 311
 312 unsigned char read_byte(int f)
 313 {
 314         unsigned char c;
 315         read_buf(f,(char *)&c,1);
 316         return c;
 317 }
 318
 319
 320
 321 /* write len bytes to fd, possibly reading from buffer_f_in if set
 322    in order to unclog the pipe. don't return until all len
 323    bytes have been written */
 324 static void writefd_unbuffered(int fd,char *buf,int len)
 325 {
 326         int total = 0;
 327         fd_set w_fds, r_fds;
 328         int fd_count, count;
 329         struct timeval tv;
 330         int reading=0;
 331
 332         no_flush++;
 333
 334         while (total < len) {
 335                 FD_ZERO(&w_fds);
 336                 FD_ZERO(&r_fds);
 337                 FD_SET(fd,&w_fds);
 338                 fd_count = fd+1;
 339
 340                 if (!no_flush_read) {
 341                         reading = (buffer_f_in != -1);
 342                 }
 343
 344                 if (reading) {
 345                         FD_SET(buffer_f_in,&r_fds);
 346                         if (buffer_f_in > fd)
 347                                 fd_count = buffer_f_in+1;
 348                 }
 349
 350                 tv.tv_sec = io_timeout?io_timeout:SELECT_TIMEOUT;
 351                 tv.tv_usec = 0;
 352
 353                 count = select(fd_count,
 354                                reading?&r_fds:NULL,
 355                                &w_fds,NULL,
 356                                &tv);
 357
 358                 if (count <= 0) {
 359                         check_timeout();
 360                         continue;
 361                 }
 362
 363                 if (reading && FD_ISSET(buffer_f_in, &r_fds)) {
 364                         read_check(buffer_f_in);
 365                 }
 366
 367                 if (FD_ISSET(fd, &w_fds)) {
 368                         int ret, n = len-total;
 369
 370                         if (n > PIPE_BUF) n = PIPE_BUF;
 371
 372                         ret = write(fd,buf+total,n?n:1);
 373
 374                         if (ret == -1 && errno == EINTR) {
 375                                 continue;
 376                         }
 377
 378                         if (ret <= 0) {
 379                                 rprintf(FERROR,"erroring writing %d bytes - exiting\n", len);
 380                                 exit_cleanup(RERR_STREAMIO);
 381                         }
 382
 383                         total += ret;
 384
 385                         if (io_timeout)
 386                                 last_io = time(NULL);
 387                 }
 388         }
 389
 390         no_flush--;
 391 }
 392
 393
 394 static char *io_buffer;
 395 static int io_buffer_count;
 396
 397 void io_start_buffering(int fd)
 398 {
 399         if (io_buffer) return;
 400         multiplex_out_fd = fd;
 401         io_buffer = (char *)malloc(IO_BUFFER_SIZE+4);
 402         if (!io_buffer) out_of_memory("writefd");
 403         io_buffer_count = 0;
 404
 405         /* leave room for the multiplex header in case it's needed */
 406         io_buffer += 4;
 407 }
 408
 409 void io_flush(void)
 410 {
 411         int fd = multiplex_out_fd;
 412         if (!io_buffer_count || no_flush) return;
 413
 414         if (io_multiplexing_out) {
 415                 SIVAL(io_buffer-4, 0, (MPLEX_BASE<<24) + io_buffer_count);
 416                 writefd_unbuffered(fd, io_buffer-4, io_buffer_count+4);
 417         } else {
 418                 writefd_unbuffered(fd, io_buffer, io_buffer_count);
 419         }
 420         io_buffer_count = 0;
 421 }
 422
 423 void io_end_buffering(int fd)
 424 {
 425         io_flush();
 426         if (!io_multiplexing_out) {
 427                 free(io_buffer-4);
 428                 io_buffer = NULL;
 429         }
 430 }
 431
 432 static void writefd(int fd,char *buf,int len)
 433 {
 434         stats.total_written += len;
 435
 436         if (!io_buffer) {
 437                 writefd_unbuffered(fd, buf, len);
 438                 return;
 439         }
 440
 441         while (len) {
 442                 int n = MIN(len, IO_BUFFER_SIZE-io_buffer_count);
 443                 if (n > 0) {
 444                         memcpy(io_buffer+io_buffer_count, buf, n);
 445                         buf += n;
 446                         len -= n;
 447                         io_buffer_count += n;
 448                 }
 449
 450                 if (io_buffer_count == IO_BUFFER_SIZE) io_flush();
 451         }
 452 }
 453
 454
 455 void write_int(int f,int32 x)
 456 {
 457         char b[4];
 458         SIVAL(b,0,x);
 459         writefd(f,b,4);
 460 }
 461
 462 void write_longint(int f, int64 x)
 463 {
 464         extern int remote_version;
 465         char b[8];
 466
 467         if (remote_version < 16 || x <= 0x7FFFFFFF) {
 468                 write_int(f, (int)x);
 469                 return;
 470         }
 471
 472         write_int(f, (int32)0xFFFFFFFF);
 473         SIVAL(b,0,(x&0xFFFFFFFF));
 474         SIVAL(b,4,((x>>32)&0xFFFFFFFF));
 475
 476         writefd(f,b,8);
 477 }
 478
 479 void write_buf(int f,char *buf,int len)
 480 {
 481         writefd(f,buf,len);
 482 }
 483
 484 /* write a string to the connection */
 485 static void write_sbuf(int f,char *buf)
 486 {
 487         write_buf(f, buf, strlen(buf));
 488 }
 489
 490
 491 void write_byte(int f,unsigned char c)
 492 {
 493         write_buf(f,(char *)&c,1);
 494 }
 495
 496 int read_line(int f, char *buf, int maxlen)
 497 {
 498         eof_error = 0;
 499
 500         while (maxlen) {
 501                 buf[0] = 0;
 502                 read_buf(f, buf, 1);
 503                 if (buf[0] == 0) return 0;
 504                 if (buf[0] == '\n') {
 505                         buf[0] = 0;
 506                         break;
 507                 }
 508                 if (buf[0] != '\r') {
 509                         buf++;
 510                         maxlen--;
 511                 }
 512         }
 513         if (maxlen == 0) {
 514                 *buf = 0;
 515                 return 0;
 516         }
 517
 518         eof_error = 1;
 519
 520         return 1;
 521 }
 522
 523
 524 void io_printf(int fd, const char *format, ...)
 525 {
 526         va_list ap;
 527         char buf[1024];
 528         int len;
 529
 530         va_start(ap, format);
 531         len = vslprintf(buf, sizeof(buf), format, ap);
 532         va_end(ap);
 533
 534         if (len < 0) exit_cleanup(RERR_STREAMIO);
 535
 536         write_sbuf(fd, buf);
 537 }
 538
 539
 540 /* setup for multiplexing an error stream with the data stream */
 541 void io_start_multiplex_out(int fd)
 542 {
 543         multiplex_out_fd = fd;
 544         io_flush();
 545         io_start_buffering(fd);
 546         io_multiplexing_out = 1;
 547 }
 548
 549 /* setup for multiplexing an error stream with the data stream */
 550 void io_start_multiplex_in(int fd)
 551 {
 552         multiplex_in_fd = fd;
 553         io_flush();
 554         if (read_buffer_len) {
 555                 fprintf(stderr,"ERROR: data in read buffer at mplx start\n");
 556                 exit_cleanup(RERR_STREAMIO);
 557         }
 558
 559         io_multiplexing_in = 1;
 560 }
 561
 562 /* write an message to the error stream */
 563 int io_multiplex_write(int f, char *buf, int len)
 564 {
 565         if (!io_multiplexing_out) return 0;
 566
 567         io_flush();
 568
 569         SIVAL(io_buffer-4, 0, ((MPLEX_BASE + f)<<24) + len);
 570         memcpy(io_buffer, buf, len);
 571
 572         stats.total_written += (len+4);
 573
 574         writefd_unbuffered(multiplex_out_fd, io_buffer-4, len+4);
 575         return 1;
 576 }
 577
 578 void io_close_input(int fd)
 579 {
 580         buffer_f_in = -1;
 581 }