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(1);
  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
  74 /* read from a socket with IO timeout. return the number of
  75    bytes read. If no bytes can be read then exit, never return
  76    a number <= 0 */
  77 static int read_timeout(int fd, char *buf, int len)
  78 {
  79         int n, ret=0;
  80
  81         io_flush();
  82
  83         while (ret == 0) {
  84                 fd_set fds;
  85                 struct timeval tv;
  86
  87                 FD_ZERO(&fds);
  88                 FD_SET(fd, &fds);
  89                 tv.tv_sec = io_timeout?io_timeout:SELECT_TIMEOUT;
  90                 tv.tv_usec = 0;
  91
  92                 if (select(fd+1, &fds, NULL, NULL, &tv) != 1) {
  93                         check_timeout();
  94                         continue;
  95                 }
  96
  97                 n = read(fd, buf, len);
  98
  99                 if (n > 0) {
 100                         stats.total_read += n;
 101                         buf += n;
 102                         len -= n;
 103                         ret += n;
 104                         if (io_timeout)
 105                                 last_io = time(NULL);
 106                         continue;
 107                 }
 108
 109                 if (n == -1 && errno == EINTR) {
 110                         continue;
 111                 }
 112
 113                 if (n == -1 &&
 114                     (errno == EAGAIN || errno == EWOULDBLOCK)) {
 115                         /* this shouldn't happen, if it does then
 116                            sleep for a short time to prevent us
 117                            chewing too much CPU */
 118                         u_sleep(100);
 119                         continue;
 120                 }
 121
 122                 if (n == 0) {
 123                         if (eof_error) {
 124                                 rprintf(FERROR,"unexpected 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 handling 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         return IVAL(b,0);
 270 }
 271
 272 int64 read_longint(int f)
 273 {
 274         extern int remote_version;
 275         int64 ret;
 276         char b[8];
 277         ret = read_int(f);
 278
 279         if ((int32)ret != (int32)0xffffffff) return ret;
 280
 281 #ifdef NO_INT64
 282         rprintf(FERROR,"Integer overflow - attempted 64 bit offset\n");
 283         exit_cleanup(1);
 284 #else
 285         if (remote_version >= 16) {
 286                 readfd(f,b,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 }
 298
 299 void read_sbuf(int f,char *buf,int len)
 300 {
 301         read_buf(f,buf,len);
 302         buf[len] = 0;
 303 }
 304
 305 unsigned char read_byte(int f)
 306 {
 307         unsigned char c;
 308         read_buf(f,(char *)&c,1);
 309         return c;
 310 }
 311
 312
 313
 314 /* write len bytes to fd, possibly reading from buffer_f_in if set
 315    in order to unclog the pipe. don't return until all len
 316    bytes have been written */
 317 static void writefd_unbuffered(int fd,char *buf,int len)
 318 {
 319         int total = 0;
 320         fd_set w_fds, r_fds;
 321         int fd_count, count;
 322         struct timeval tv;
 323         int reading;
 324         int blocked=0;
 325
 326         no_flush++;
 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                 reading = (buffer_f_in != -1 &&
 335                            read_buffer_len < MAX_READ_BUFFER);
 336
 337                 if (reading) {
 338                         FD_SET(buffer_f_in,&r_fds);
 339                         if (buffer_f_in > fd)
 340                                 fd_count = buffer_f_in+1;
 341                 }
 342
 343                 tv.tv_sec = io_timeout?io_timeout:SELECT_TIMEOUT;
 344                 tv.tv_usec = 0;
 345
 346                 count = select(fd_count,
 347                                reading?&r_fds:NULL,
 348                                &w_fds,NULL,
 349                                &tv);
 350
 351                 if (count <= 0) {
 352                         check_timeout();
 353                         continue;
 354                 }
 355
 356                 if (reading && FD_ISSET(buffer_f_in, &r_fds)) {
 357                         read_check(buffer_f_in);
 358                 }
 359
 360                 if (FD_ISSET(fd, &w_fds)) {
 361                         int n = (len-total)>>blocked;
 362                         int ret = write(fd,buf+total,n?n:1);
 363
 364                         if (ret == -1 && errno == EINTR) {
 365                                 continue;
 366                         }
 367
 368                         if (ret == -1 &&
 369                             (errno == EAGAIN || errno == EWOULDBLOCK)) {
 370                                 blocked++;
 371                                 continue;
 372                         }
 373
 374                         if (ret <= 0) {
 375                                 rprintf(FERROR,"erroring writing %d bytes - exiting\n", len);
 376                                 exit_cleanup(1);
 377                         }
 378
 379                         blocked = 0;
 380                         total += ret;
 381                         stats.total_written += ret;
 382
 383                         if (io_timeout)
 384                                 last_io = time(NULL);
 385                 }
 386         }
 387
 388         no_flush--;
 389 }
 390
 391
 392 static char *io_buffer;
 393 static int io_buffer_count;
 394
 395 void io_start_buffering(int fd)
 396 {
 397         if (io_buffer) return;
 398         multiplex_out_fd = fd;
 399         io_buffer = (char *)malloc(IO_BUFFER_SIZE+4);
 400         if (!io_buffer) out_of_memory("writefd");
 401         io_buffer_count = 0;
 402
 403         /* leave room for the multiplex header in case it's needed */
 404         io_buffer += 4;
 405 }
 406
 407 void io_flush(void)
 408 {
 409         int fd = multiplex_out_fd;
 410         if (!io_buffer_count || no_flush) return;
 411
 412         if (io_multiplexing_out) {
 413                 SIVAL(io_buffer-4, 0, (MPLEX_BASE<<24) + io_buffer_count);
 414                 writefd_unbuffered(fd, io_buffer-4, io_buffer_count+4);
 415         } else {
 416                 writefd_unbuffered(fd, io_buffer, io_buffer_count);
 417         }
 418         io_buffer_count = 0;
 419 }
 420
 421 void io_end_buffering(int fd)
 422 {
 423         io_flush();
 424         if (!io_multiplexing_out) {
 425                 free(io_buffer-4);
 426                 io_buffer = NULL;
 427         }
 428 }
 429
 430 static void writefd(int fd,char *buf,int len)
 431 {
 432         if (!io_buffer) {
 433                 writefd_unbuffered(fd, buf, len);
 434                 return;
 435         }
 436
 437         while (len) {
 438                 int n = MIN(len, IO_BUFFER_SIZE-io_buffer_count);
 439                 if (n > 0) {
 440                         memcpy(io_buffer+io_buffer_count, buf, n);
 441                         buf += n;
 442                         len -= n;
 443                         io_buffer_count += n;
 444                 }
 445
 446                 if (io_buffer_count == IO_BUFFER_SIZE) io_flush();
 447         }
 448 }
 449
 450
 451 void write_int(int f,int32 x)
 452 {
 453         char b[4];
 454         SIVAL(b,0,x);
 455         writefd(f,b,4);
 456 }
 457
 458 void write_longint(int f, int64 x)
 459 {
 460         extern int remote_version;
 461         char b[8];
 462
 463         if (remote_version < 16 || x <= 0x7FFFFFFF) {
 464                 write_int(f, (int)x);
 465                 return;
 466         }
 467
 468         write_int(f, -1);
 469         SIVAL(b,0,(x&0xFFFFFFFF));
 470         SIVAL(b,4,((x>>32)&0xFFFFFFFF));
 471
 472         writefd(f,b,8);
 473 }
 474
 475 void write_buf(int f,char *buf,int len)
 476 {
 477         writefd(f,buf,len);
 478 }
 479
 480 /* write a string to the connection */
 481 void write_sbuf(int f,char *buf)
 482 {
 483         write_buf(f, buf, strlen(buf));
 484 }
 485
 486
 487 void write_byte(int f,unsigned char c)
 488 {
 489         write_buf(f,(char *)&c,1);
 490 }
 491
 492 int read_line(int f, char *buf, int maxlen)
 493 {
 494         eof_error = 0;
 495
 496         while (maxlen) {
 497                 buf[0] = 0;
 498                 read_buf(f, buf, 1);
 499                 if (buf[0] == 0) return 0;
 500                 if (buf[0] == '\n') {
 501                         buf[0] = 0;
 502                         break;
 503                 }
 504                 if (buf[0] != '\r') {
 505                         buf++;
 506                         maxlen--;
 507                 }
 508         }
 509         if (maxlen == 0) {
 510                 *buf = 0;
 511                 return 0;
 512         }
 513
 514         eof_error = 1;
 515
 516         return 1;
 517 }
 518
 519
 520 void io_printf(int fd, const char *format, ...)
 521 {
 522         va_list ap;
 523         char buf[1024];
 524         int len;
 525
 526         va_start(ap, format);
 527         len = vslprintf(buf, sizeof(buf)-1, format, ap);
 528         va_end(ap);
 529
 530         if (len < 0) exit_cleanup(1);
 531
 532         write_sbuf(fd, buf);
 533 }
 534
 535
 536 /* setup for multiplexing an error stream with the data stream */
 537 void io_start_multiplex_out(int fd)
 538 {
 539         multiplex_out_fd = fd;
 540         io_flush();
 541         io_start_buffering(fd);
 542         io_multiplexing_out = 1;
 543 }
 544
 545 /* setup for multiplexing an error stream with the data stream */
 546 void io_start_multiplex_in(int fd)
 547 {
 548         multiplex_in_fd = fd;
 549         io_flush();
 550         if (read_buffer_len) {
 551                 fprintf(stderr,"ERROR: data in read buffer at mplx start\n");
 552                 exit_cleanup(1);
 553         }
 554
 555         io_multiplexing_in = 1;
 556 }
 557
 558 /* write an message to the error stream */
 559 int io_multiplex_write(int f, char *buf, int len)
 560 {
 561         if (!io_multiplexing_out) return 0;
 562
 563         io_flush();
 564
 565         SIVAL(io_buffer-4, 0, ((MPLEX_BASE + f)<<24) + len);
 566         memcpy(io_buffer, buf, len);
 567
 568         writefd_unbuffered(multiplex_out_fd, io_buffer-4, len+4);
 569         return 1;
 570 }
 571
 572 void io_close_input(int fd)
 573 {
 574         buffer_f_in = -1;
 575 }