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 int io_multiplexing_out;
  28 static int io_multiplexing_in;
  29 static int multiplex_in_fd;
  30 static int multiplex_out_fd;
  31 static time_t last_io;
  32 static int eof_error=1;
  33 extern int verbose;
  34 extern int io_timeout;
  35 extern struct stats stats;
  36
  37 static int buffer_f_in = -1;
  38
  39 void setup_readbuffer(int f_in)
  40 {
  41         buffer_f_in = f_in;
  42 }
  43
  44 static void check_timeout(void)
  45 {
  46         time_t t;
  47
  48         if (!io_timeout) return;
  49
  50         if (!last_io) {
  51                 last_io = time(NULL);
  52                 return;
  53         }
  54
  55         t = time(NULL);
  56
  57         if (last_io && io_timeout && (t-last_io) >= io_timeout) {
  58                 rprintf(FERROR,"io timeout after %d second - exiting\n",
  59                         (int)(t-last_io));
  60                 exit_cleanup(1);
  61         }
  62 }
  63
  64
  65 static char *read_buffer;
  66 static char *read_buffer_p;
  67 static int read_buffer_len;
  68 static int read_buffer_size;
  69 static int no_flush;
  70
  71 /* read from a socket with IO timeout. return the number of
  72    bytes read. If no bytes can be read then exit, never return
  73    a number <= 0 */
  74 static int read_timeout(int fd, char *buf, int len)
  75 {
  76         int n, ret=0;
  77
  78         io_flush();
  79
  80         while (ret == 0) {
  81                 fd_set fds;
  82                 struct timeval tv;
  83
  84                 FD_ZERO(&fds);
  85                 FD_SET(fd, &fds);
  86                 tv.tv_sec = io_timeout;
  87                 tv.tv_usec = 0;
  88
  89                 if (select(fd+1, &fds, NULL, NULL,
  90                            io_timeout?&tv:NULL) != 1) {
  91                         check_timeout();
  92                         continue;
  93                 }
  94
  95                 n = read(fd, buf, len);
  96
  97                 if (n > 0) {
  98                         stats.total_read += n;
  99                         buf += n;
 100                         len -= n;
 101                         ret += n;
 102                         if (io_timeout)
 103                                 last_io = time(NULL);
 104                         continue;
 105                 }
 106
 107                 if (n == -1 && errno == EINTR) {
 108                         continue;
 109                 }
 110
 111                 if (n == -1 &&
 112                     (errno == EAGAIN || errno == EWOULDBLOCK)) {
 113                         /* this shouldn't happen, if it does then
 114                            sleep for a short time to prevent us
 115                            chewing too much CPU */
 116                         u_sleep(100);
 117                         continue;
 118                 }
 119
 120                 if (n == 0) {
 121                         if (eof_error) {
 122                                 rprintf(FERROR,"EOF in read_timeout\n");
 123                         }
 124                         exit_cleanup(1);
 125                 }
 126
 127                 rprintf(FERROR,"read error: %s\n", strerror(errno));
 128                 exit_cleanup(1);
 129         }
 130
 131         return ret;
 132 }
 133
 134 /* continue trying to read len bytes - don't return until len
 135    has been read */
 136 static void read_loop(int fd, char *buf, int len)
 137 {
 138         while (len) {
 139                 int n = read_timeout(fd, buf, len);
 140
 141                 buf += n;
 142                 len -= n;
 143         }
 144 }
 145
 146 /* read from the file descriptor handling multiplexing -
 147    return number of bytes read
 148    never return <= 0 */
 149 static int read_unbuffered(int fd, char *buf, int len)
 150 {
 151         static int remaining;
 152         char ibuf[4];
 153         int tag, ret=0;
 154         char line[1024];
 155
 156         if (!io_multiplexing_in || fd != multiplex_in_fd)
 157                 return read_timeout(fd, buf, len);
 158
 159         while (ret == 0) {
 160                 if (remaining) {
 161                         len = MIN(len, remaining);
 162                         read_loop(fd, buf, len);
 163                         remaining -= len;
 164                         ret = len;
 165                         continue;
 166                 }
 167
 168                 read_loop(fd, ibuf, 4);
 169                 tag = IVAL(ibuf, 0);
 170
 171                 remaining = tag & 0xFFFFFF;
 172                 tag = tag >> 24;
 173
 174                 if (tag == MPLEX_BASE) continue;
 175
 176                 tag -= MPLEX_BASE;
 177
 178                 if (tag != FERROR && tag != FINFO) {
 179                         rprintf(FERROR,"unexpected tag %d\n", tag);
 180                         exit_cleanup(1);
 181                 }
 182
 183                 if (remaining > sizeof(line)-1) {
 184                         rprintf(FERROR,"multiplexing overflow %d\n\n",
 185                                 remaining);
 186                         exit_cleanup(1);
 187                 }
 188
 189                 read_loop(fd, line, remaining);
 190                 line[remaining] = 0;
 191
 192                 rprintf(tag,"%s", line);
 193                 remaining = 0;
 194         }
 195
 196         return ret;
 197 }
 198
 199
 200
 201 /* This function was added to overcome a deadlock problem when using
 202  * ssh.  It looks like we can't allow our receive queue to get full or
 203  * ssh will clag up. Uggh.  */
 204 static void read_check(int f)
 205 {
 206         int n = 8192;
 207
 208         if (f == -1) return;
 209
 210         if (read_buffer_len == 0) {
 211                 read_buffer_p = read_buffer;
 212         }
 213
 214         if (n > MAX_READ_BUFFER/4)
 215                 n = MAX_READ_BUFFER/4;
 216
 217         if (read_buffer_p != read_buffer) {
 218                 memmove(read_buffer,read_buffer_p,read_buffer_len);
 219                 read_buffer_p = read_buffer;
 220         }
 221
 222         if (n > (read_buffer_size - read_buffer_len)) {
 223                 read_buffer_size += n;
 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         return IVAL(b,0);
 268 }
 269
 270 int64 read_longint(int f)
 271 {
 272         extern int remote_version;
 273         int64 ret;
 274         char b[8];
 275         ret = read_int(f);
 276
 277         if ((int32)ret != (int32)0xffffffff) return ret;
 278
 279 #ifdef NO_INT64
 280         rprintf(FERROR,"Integer overflow - attempted 64 bit offset\n");
 281         exit_cleanup(1);
 282 #else
 283         if (remote_version >= 16) {
 284                 readfd(f,b,8);
 285                 ret = IVAL(b,0) | (((int64)IVAL(b,4))<<32);
 286         }
 287 #endif
 288
 289         return ret;
 290 }
 291
 292 void read_buf(int f,char *buf,int len)
 293 {
 294         readfd(f,buf,len);
 295 }
 296
 297 void read_sbuf(int f,char *buf,int len)
 298 {
 299         read_buf(f,buf,len);
 300         buf[len] = 0;
 301 }
 302
 303 unsigned char read_byte(int f)
 304 {
 305         unsigned char c;
 306         read_buf(f,(char *)&c,1);
 307         return c;
 308 }
 309
 310
 311
 312 /* write len bytes to fd, possibly reading from buffer_f_in if set
 313    in order to unclog the pipe. don't return until all len
 314    bytes have been written */
 315 static void writefd_unbuffered(int fd,char *buf,int len)
 316 {
 317         int total = 0;
 318         fd_set w_fds, r_fds;
 319         int fd_count, count;
 320         struct timeval tv;
 321         int reading;
 322         int blocked=0;
 323
 324         no_flush++;
 325
 326         while (total < len) {
 327                 FD_ZERO(&w_fds);
 328                 FD_ZERO(&r_fds);
 329                 FD_SET(fd,&w_fds);
 330                 fd_count = fd+1;
 331
 332                 reading = (buffer_f_in != -1 &&
 333                            read_buffer_len < MAX_READ_BUFFER);
 334
 335                 if (reading) {
 336                         FD_SET(buffer_f_in,&r_fds);
 337                         if (buffer_f_in > fd)
 338                                 fd_count = buffer_f_in+1;
 339                 }
 340
 341                 tv.tv_sec = io_timeout;
 342                 tv.tv_usec = 0;
 343
 344                 count = select(fd_count,
 345                                reading?&r_fds:NULL,
 346                                &w_fds,NULL,
 347                                io_timeout?&tv:NULL);
 348
 349                 if (count <= 0) {
 350                         check_timeout();
 351                         continue;
 352                 }
 353
 354                 if (reading && FD_ISSET(buffer_f_in, &r_fds)) {
 355                         read_check(buffer_f_in);
 356                 }
 357
 358                 if (FD_ISSET(fd, &w_fds)) {
 359                         int n = (len-total)>>blocked;
 360                         int ret = write(fd,buf+total,n?n:1);
 361
 362                         if (ret == -1 && errno == EINTR) {
 363                                 continue;
 364                         }
 365
 366                         if (ret == -1 &&
 367                             (errno == EAGAIN || errno == EWOULDBLOCK)) {
 368                                 blocked++;
 369                                 continue;
 370                         }
 371
 372                         if (ret <= 0) {
 373                                 rprintf(FERROR,"erroring writing %d bytes - exiting\n", len);
 374                                 exit_cleanup(1);
 375                         }
 376
 377                         blocked = 0;
 378                         total += ret;
 379                         stats.total_written += ret;
 380
 381                         if (io_timeout)
 382                                 last_io = time(NULL);
 383                         continue;
 384                 }
 385         }
 386
 387         no_flush--;
 388 }
 389
 390
 391 static char *io_buffer;
 392 static int io_buffer_count;
 393
 394 void io_start_buffering(int fd)
 395 {
 396         if (io_buffer) return;
 397         multiplex_out_fd = fd;
 398         io_buffer = (char *)malloc(IO_BUFFER_SIZE+4);
 399         if (!io_buffer) out_of_memory("writefd");
 400         io_buffer_count = 0;
 401
 402         /* leave room for the multiplex header in case it's needed */
 403         io_buffer += 4;
 404 }
 405
 406 void io_flush(void)
 407 {
 408         int fd = multiplex_out_fd;
 409         if (!io_buffer_count || no_flush) return;
 410
 411         if (io_multiplexing_out) {
 412                 SIVAL(io_buffer-4, 0, (MPLEX_BASE<<24) + io_buffer_count);
 413                 writefd_unbuffered(fd, io_buffer-4, io_buffer_count+4);
 414         } else {
 415                 writefd_unbuffered(fd, io_buffer, io_buffer_count);
 416         }
 417         io_buffer_count = 0;
 418 }
 419
 420 void io_end_buffering(int fd)
 421 {
 422         io_flush();
 423         if (!io_multiplexing_out) {
 424                 free(io_buffer-4);
 425                 io_buffer = NULL;
 426         }
 427 }
 428
 429 static void writefd(int fd,char *buf,int len)
 430 {
 431         if (!io_buffer) {
 432                 writefd_unbuffered(fd, buf, len);
 433                 return;
 434         }
 435
 436         while (len) {
 437                 int n = MIN(len, IO_BUFFER_SIZE-io_buffer_count);
 438                 if (n > 0) {
 439                         memcpy(io_buffer+io_buffer_count, buf, n);
 440                         buf += n;
 441                         len -= n;
 442                         io_buffer_count += n;
 443                 }
 444
 445                 if (io_buffer_count == IO_BUFFER_SIZE) io_flush();
 446         }
 447 }
 448
 449
 450 void write_int(int f,int32 x)
 451 {
 452         char b[4];
 453         SIVAL(b,0,x);
 454         writefd(f,b,4);
 455 }
 456
 457 void write_longint(int f, int64 x)
 458 {
 459         extern int remote_version;
 460         char b[8];
 461
 462         if (remote_version < 16 || x <= 0x7FFFFFFF) {
 463                 write_int(f, (int)x);
 464                 return;
 465         }
 466
 467         write_int(f, -1);
 468         SIVAL(b,0,(x&0xFFFFFFFF));
 469         SIVAL(b,4,((x>>32)&0xFFFFFFFF));
 470
 471         writefd(f,b,8);
 472 }
 473
 474 void write_buf(int f,char *buf,int len)
 475 {
 476         writefd(f,buf,len);
 477 }
 478
 479 /* write a string to the connection */
 480 void write_sbuf(int f,char *buf)
 481 {
 482         write_buf(f, buf, strlen(buf));
 483 }
 484
 485
 486 void write_byte(int f,unsigned char c)
 487 {
 488         write_buf(f,(char *)&c,1);
 489 }
 490
 491 int read_line(int f, char *buf, int maxlen)
 492 {
 493         eof_error = 0;
 494
 495         while (maxlen) {
 496                 buf[0] = 0;
 497                 read_buf(f, buf, 1);
 498                 if (buf[0] == 0) return 0;
 499                 if (buf[0] == '\n') {
 500                         buf[0] = 0;
 501                         break;
 502                 }
 503                 if (buf[0] != '\r') {
 504                         buf++;
 505                         maxlen--;
 506                 }
 507         }
 508         if (maxlen == 0) {
 509                 *buf = 0;
 510                 return 0;
 511         }
 512
 513         eof_error = 1;
 514
 515         return 1;
 516 }
 517
 518
 519 void io_printf(int fd, const char *format, ...)
 520 {
 521         va_list ap;
 522         char buf[1024];
 523         int len;
 524
 525         va_start(ap, format);
 526         len = vslprintf(buf, sizeof(buf)-1, format, ap);
 527         va_end(ap);
 528
 529         if (len < 0) exit_cleanup(1);
 530
 531         write_sbuf(fd, buf);
 532 }
 533
 534
 535 /* setup for multiplexing an error stream with the data stream */
 536 void io_start_multiplex_out(int fd)
 537 {
 538         multiplex_out_fd = fd;
 539         io_flush();
 540         io_start_buffering(fd);
 541         io_multiplexing_out = 1;
 542 }
 543
 544 /* setup for multiplexing an error stream with the data stream */
 545 void io_start_multiplex_in(int fd)
 546 {
 547         multiplex_in_fd = fd;
 548         io_flush();
 549         if (read_buffer_len) {
 550                 fprintf(stderr,"ERROR: data in read buffer at mplx start\n");
 551                 exit_cleanup(1);
 552         }
 553
 554         io_multiplexing_in = 1;
 555 }
 556
 557 /* write an message to the error stream */
 558 int io_multiplex_write(int f, char *buf, int len)
 559 {
 560         if (!io_multiplexing_out) return 0;
 561
 562         io_flush();
 563
 564         SIVAL(io_buffer-4, 0, ((MPLEX_BASE + f)<<24) + len);
 565         memcpy(io_buffer, buf, len);
 566
 567         writefd_unbuffered(multiplex_out_fd, io_buffer-4, len+4);
 568         return 1;
 569 }
 570
 571 void io_close_input(int fd)
 572 {
 573         buffer_f_in = -1;
 574 }