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 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                 if (n == -1 &&
 116                     (errno == EAGAIN || errno == EWOULDBLOCK)) {
 117                         /* this shouldn't happen, if it does then
 118                            sleep for a short time to prevent us
 119                            chewing too much CPU */
 120                         u_sleep(100);
 121                         continue;
 122                 }
 123
 124                 if (n == 0) {
 125                         if (eof_error) {
 126                                 rprintf(FERROR,"unexpected EOF in read_timeout\n");
 127                         }
 128                         exit_cleanup(1);
 129                 }
 130
 131                 rprintf(FERROR,"read error: %s\n", strerror(errno));
 132                 exit_cleanup(1);
 133         }
 134
 135         return ret;
 136 }
 137
 138 /* continue trying to read len bytes - don't return until len
 139    has been read */
 140 static void read_loop(int fd, char *buf, int len)
 141 {
 142         while (len) {
 143                 int n = read_timeout(fd, buf, len);
 144
 145                 buf += n;
 146                 len -= n;
 147         }
 148 }
 149
 150 /* read from the file descriptor handling multiplexing -
 151    return number of bytes read
 152    never return <= 0 */
 153 static int read_unbuffered(int fd, char *buf, int len)
 154 {
 155         static int remaining;
 156         char ibuf[4];
 157         int tag, ret=0;
 158         char line[1024];
 159
 160         if (!io_multiplexing_in || fd != multiplex_in_fd)
 161                 return read_timeout(fd, buf, len);
 162
 163         while (ret == 0) {
 164                 if (remaining) {
 165                         len = MIN(len, remaining);
 166                         read_loop(fd, buf, len);
 167                         remaining -= len;
 168                         ret = len;
 169                         continue;
 170                 }
 171
 172                 read_loop(fd, ibuf, 4);
 173                 tag = IVAL(ibuf, 0);
 174
 175                 remaining = tag & 0xFFFFFF;
 176                 tag = tag >> 24;
 177
 178                 if (tag == MPLEX_BASE) continue;
 179
 180                 tag -= MPLEX_BASE;
 181
 182                 if (tag != FERROR && tag != FINFO) {
 183                         rprintf(FERROR,"unexpected tag %d\n", tag);
 184                         exit_cleanup(1);
 185                 }
 186
 187                 if (remaining > sizeof(line)-1) {
 188                         rprintf(FERROR,"multiplexing overflow %d\n\n",
 189                                 remaining);
 190                         exit_cleanup(1);
 191                 }
 192
 193                 read_loop(fd, line, remaining);
 194                 line[remaining] = 0;
 195
 196                 rprintf(tag,"%s", line);
 197                 remaining = 0;
 198         }
 199
 200         return ret;
 201 }
 202
 203
 204
 205 /* This function was added to overcome a deadlock problem when using
 206  * ssh.  It looks like we can't allow our receive queue to get full or
 207  * ssh will clag up. Uggh.  */
 208 static void read_check(int f)
 209 {
 210         int n = 8192;
 211
 212         if (f == -1) return;
 213
 214         if (read_buffer_len == 0) {
 215                 read_buffer_p = read_buffer;
 216         }
 217
 218         if (n > MAX_READ_BUFFER/4)
 219                 n = MAX_READ_BUFFER/4;
 220
 221         if (read_buffer_p != read_buffer) {
 222                 memmove(read_buffer,read_buffer_p,read_buffer_len);
 223                 read_buffer_p = read_buffer;
 224         }
 225
 226         if (n > (read_buffer_size - read_buffer_len)) {
 227                 read_buffer_size += n;
 228                 read_buffer = (char *)Realloc(read_buffer,read_buffer_size);
 229                 if (!read_buffer) out_of_memory("read check");
 230                 read_buffer_p = read_buffer;
 231         }
 232
 233         n = read_unbuffered(f,read_buffer+read_buffer_len,n);
 234         read_buffer_len += n;
 235 }
 236
 237
 238 /* do a buffered read from fd. don't return until all N bytes
 239    have been read. If all N can't be read then exit with an error */
 240 static void readfd(int fd,char *buffer,int N)
 241 {
 242         int  ret;
 243         int total=0;
 244
 245         if ((read_buffer_len < N) && (N < 1024)) {
 246                 read_check(buffer_f_in);
 247         }
 248
 249         while (total < N) {
 250                 if (read_buffer_len > 0 && buffer_f_in == fd) {
 251                         ret = MIN(read_buffer_len,N-total);
 252                         memcpy(buffer+total,read_buffer_p,ret);
 253                         read_buffer_p += ret;
 254                         read_buffer_len -= ret;
 255                         total += ret;
 256                         continue;
 257                 }
 258
 259                 no_flush_read++;
 260                 io_flush();
 261                 no_flush_read--;
 262
 263                 ret = read_unbuffered(fd,buffer + total,N-total);
 264                 total += ret;
 265         }
 266
 267         stats.total_read += total;
 268 }
 269
 270
 271 int32 read_int(int f)
 272 {
 273         char b[4];
 274         int32 ret;
 275
 276         readfd(f,b,4);
 277         ret = IVAL(b,0);
 278         if (ret == (int32)0xffffffff) return -1;
 279         return ret;
 280 }
 281
 282 int64 read_longint(int f)
 283 {
 284         extern int remote_version;
 285         int64 ret;
 286         char b[8];
 287         ret = read_int(f);
 288
 289         if ((int32)ret != (int32)0xffffffff) {
 290                 return ret;
 291         }
 292
 293 #ifdef NO_INT64
 294         rprintf(FERROR,"Integer overflow - attempted 64 bit offset\n");
 295         exit_cleanup(1);
 296 #else
 297         if (remote_version >= 16) {
 298                 readfd(f,b,8);
 299                 ret = IVAL(b,0) | (((int64)IVAL(b,4))<<32);
 300         }
 301 #endif
 302
 303         return ret;
 304 }
 305
 306 void read_buf(int f,char *buf,int len)
 307 {
 308         readfd(f,buf,len);
 309 }
 310
 311 void read_sbuf(int f,char *buf,int len)
 312 {
 313         read_buf(f,buf,len);
 314         buf[len] = 0;
 315 }
 316
 317 unsigned char read_byte(int f)
 318 {
 319         unsigned char c;
 320         read_buf(f,(char *)&c,1);
 321         return c;
 322 }
 323
 324
 325
 326 /* write len bytes to fd, possibly reading from buffer_f_in if set
 327    in order to unclog the pipe. don't return until all len
 328    bytes have been written */
 329 static void writefd_unbuffered(int fd,char *buf,int len)
 330 {
 331         int total = 0;
 332         fd_set w_fds, r_fds;
 333         int fd_count, count;
 334         struct timeval tv;
 335         int reading=0;
 336         int blocked=0;
 337
 338         no_flush++;
 339
 340         while (total < len) {
 341                 FD_ZERO(&w_fds);
 342                 FD_ZERO(&r_fds);
 343                 FD_SET(fd,&w_fds);
 344                 fd_count = fd+1;
 345
 346                 if (!no_flush_read) {
 347                         reading = (buffer_f_in != -1);
 348                 }
 349
 350                 if (reading) {
 351                         FD_SET(buffer_f_in,&r_fds);
 352                         if (buffer_f_in > fd)
 353                                 fd_count = buffer_f_in+1;
 354                 }
 355
 356                 tv.tv_sec = io_timeout?io_timeout:SELECT_TIMEOUT;
 357                 tv.tv_usec = 0;
 358
 359                 count = select(fd_count,
 360                                reading?&r_fds:NULL,
 361                                &w_fds,NULL,
 362                                &tv);
 363
 364                 if (count <= 0) {
 365                         check_timeout();
 366                         continue;
 367                 }
 368
 369                 if (reading && FD_ISSET(buffer_f_in, &r_fds)) {
 370                         read_check(buffer_f_in);
 371                 }
 372
 373                 if (FD_ISSET(fd, &w_fds)) {
 374                         int n = (len-total)>>blocked;
 375                         int ret = write(fd,buf+total,n?n:1);
 376
 377                         if (ret == -1 && errno == EINTR) {
 378                                 continue;
 379                         }
 380
 381                         if (ret == -1 &&
 382                             (errno == EAGAIN || errno == EWOULDBLOCK)) {
 383                                 blocked++;
 384                                 continue;
 385                         }
 386
 387                         if (ret <= 0) {
 388                                 rprintf(FERROR,"erroring writing %d bytes - exiting\n", len);
 389                                 exit_cleanup(1);
 390                         }
 391
 392                         blocked = 0;
 393                         total += ret;
 394
 395                         if (io_timeout)
 396                                 last_io = time(NULL);
 397                 }
 398         }
 399
 400         no_flush--;
 401 }
 402
 403
 404 static char *io_buffer;
 405 static int io_buffer_count;
 406
 407 void io_start_buffering(int fd)
 408 {
 409         if (io_buffer) return;
 410         multiplex_out_fd = fd;
 411         io_buffer = (char *)malloc(IO_BUFFER_SIZE+4);
 412         if (!io_buffer) out_of_memory("writefd");
 413         io_buffer_count = 0;
 414
 415         /* leave room for the multiplex header in case it's needed */
 416         io_buffer += 4;
 417 }
 418
 419 void io_flush(void)
 420 {
 421         int fd = multiplex_out_fd;
 422         if (!io_buffer_count || no_flush) return;
 423
 424         if (io_multiplexing_out) {
 425                 SIVAL(io_buffer-4, 0, (MPLEX_BASE<<24) + io_buffer_count);
 426                 writefd_unbuffered(fd, io_buffer-4, io_buffer_count+4);
 427         } else {
 428                 writefd_unbuffered(fd, io_buffer, io_buffer_count);
 429         }
 430         io_buffer_count = 0;
 431 }
 432
 433 void io_end_buffering(int fd)
 434 {
 435         io_flush();
 436         if (!io_multiplexing_out) {
 437                 free(io_buffer-4);
 438                 io_buffer = NULL;
 439         }
 440 }
 441
 442 static void writefd(int fd,char *buf,int len)
 443 {
 444         stats.total_written += len;
 445
 446         if (!io_buffer) {
 447                 writefd_unbuffered(fd, buf, len);
 448                 return;
 449         }
 450
 451         while (len) {
 452                 int n = MIN(len, IO_BUFFER_SIZE-io_buffer_count);
 453                 if (n > 0) {
 454                         memcpy(io_buffer+io_buffer_count, buf, n);
 455                         buf += n;
 456                         len -= n;
 457                         io_buffer_count += n;
 458                 }
 459
 460                 if (io_buffer_count == IO_BUFFER_SIZE) io_flush();
 461         }
 462 }
 463
 464
 465 void write_int(int f,int32 x)
 466 {
 467         char b[4];
 468         SIVAL(b,0,x);
 469         writefd(f,b,4);
 470 }
 471
 472 void write_longint(int f, int64 x)
 473 {
 474         extern int remote_version;
 475         char b[8];
 476
 477         if (remote_version < 16 || x <= 0x7FFFFFFF) {
 478                 write_int(f, (int)x);
 479                 return;
 480         }
 481
 482         write_int(f, (int32)0xFFFFFFFF);
 483         SIVAL(b,0,(x&0xFFFFFFFF));
 484         SIVAL(b,4,((x>>32)&0xFFFFFFFF));
 485
 486         writefd(f,b,8);
 487 }
 488
 489 void write_buf(int f,char *buf,int len)
 490 {
 491         writefd(f,buf,len);
 492 }
 493
 494 /* write a string to the connection */
 495 static void write_sbuf(int f,char *buf)
 496 {
 497         write_buf(f, buf, strlen(buf));
 498 }
 499
 500
 501 void write_byte(int f,unsigned char c)
 502 {
 503         write_buf(f,(char *)&c,1);
 504 }
 505
 506 int read_line(int f, char *buf, int maxlen)
 507 {
 508         eof_error = 0;
 509
 510         while (maxlen) {
 511                 buf[0] = 0;
 512                 read_buf(f, buf, 1);
 513                 if (buf[0] == 0) return 0;
 514                 if (buf[0] == '\n') {
 515                         buf[0] = 0;
 516                         break;
 517                 }
 518                 if (buf[0] != '\r') {
 519                         buf++;
 520                         maxlen--;
 521                 }
 522         }
 523         if (maxlen == 0) {
 524                 *buf = 0;
 525                 return 0;
 526         }
 527
 528         eof_error = 1;
 529
 530         return 1;
 531 }
 532
 533
 534 void io_printf(int fd, const char *format, ...)
 535 {
 536         va_list ap;
 537         char buf[1024];
 538         int len;
 539
 540         va_start(ap, format);
 541         len = vslprintf(buf, sizeof(buf)-1, format, ap);
 542         va_end(ap);
 543
 544         if (len < 0) exit_cleanup(1);
 545
 546         write_sbuf(fd, buf);
 547 }
 548
 549
 550 /* setup for multiplexing an error stream with the data stream */
 551 void io_start_multiplex_out(int fd)
 552 {
 553         multiplex_out_fd = fd;
 554         io_flush();
 555         io_start_buffering(fd);
 556         io_multiplexing_out = 1;
 557 }
 558
 559 /* setup for multiplexing an error stream with the data stream */
 560 void io_start_multiplex_in(int fd)
 561 {
 562         multiplex_in_fd = fd;
 563         io_flush();
 564         if (read_buffer_len) {
 565                 fprintf(stderr,"ERROR: data in read buffer at mplx start\n");
 566                 exit_cleanup(1);
 567         }
 568
 569         io_multiplexing_in = 1;
 570 }
 571
 572 /* write an message to the error stream */
 573 int io_multiplex_write(int f, char *buf, int len)
 574 {
 575         if (!io_multiplexing_out) return 0;
 576
 577         io_flush();
 578
 579         SIVAL(io_buffer-4, 0, ((MPLEX_BASE + f)<<24) + len);
 580         memcpy(io_buffer, buf, len);
 581
 582         stats.total_written += (len+4);
 583
 584         writefd_unbuffered(multiplex_out_fd, io_buffer-4, len+4);
 585         return 1;
 586 }
 587
 588 void io_close_input(int fd)
 589 {
 590         buffer_f_in = -1;
 591 }