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 static int eof_error=1;
  36 extern int verbose;
  37 extern int io_timeout;
  38
  39
  40 int64 write_total(void)
  41 {
  42         return total_written;
  43 }
  44
  45 int64 read_total(void)
  46 {
  47         return total_read;
  48 }
  49
  50 static int buffer_f_in = -1;
  51
  52 void setup_readbuffer(int f_in)
  53 {
  54         buffer_f_in = f_in;
  55 }
  56
  57 static void check_timeout(void)
  58 {
  59         time_t t;
  60
  61         if (!io_timeout) return;
  62
  63         if (!last_io) {
  64                 last_io = time(NULL);
  65                 return;
  66         }
  67
  68         t = time(NULL);
  69
  70         if (last_io && io_timeout && (t-last_io)>io_timeout) {
  71                 rprintf(FERROR,"read timeout after %d second - exiting\n",
  72                         (int)(t-last_io));
  73                 exit_cleanup(1);
  74         }
  75 }
  76
  77
  78 static char *read_buffer;
  79 static char *read_buffer_p;
  80 static int read_buffer_len;
  81 static int read_buffer_size;
  82
  83 /* read from a socket with IO timeout. return the number of
  84    bytes read. If no bytes can be read then exit, never return
  85    a number <= 0 */
  86 static int read_timeout(int fd, char *buf, int len)
  87 {
  88         int n, ret=0;
  89
  90         io_flush();
  91
  92         while (ret == 0) {
  93                 fd_set fds;
  94                 struct timeval tv;
  95
  96                 FD_ZERO(&fds);
  97                 FD_SET(fd, &fds);
  98                 tv.tv_sec = io_timeout;
  99                 tv.tv_usec = 0;
 100
 101                 if (select(fd+1, &fds, NULL, NULL,
 102                            io_timeout?&tv:NULL) != 1) {
 103                         check_timeout();
 104                         continue;
 105                 }
 106
 107                 n = read(fd, buf, len);
 108
 109                 if (n > 0) {
 110                         buf += n;
 111                         len -= n;
 112                         ret += n;
 113                         if (io_timeout)
 114                                 last_io = time(NULL);
 115                         continue;
 116                 }
 117
 118                 if (n == -1 && errno == EINTR) {
 119                         continue;
 120                 }
 121
 122                 if (n == 0) {
 123                         if (eof_error) {
 124                                 rprintf(FERROR,"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 handing 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                 if (!read_buffer)
 227                         read_buffer = (char *)malloc(read_buffer_size);
 228                 else
 229                         read_buffer = (char *)realloc(read_buffer,read_buffer_size);
 230                 if (!read_buffer) out_of_memory("read check");
 231                 read_buffer_p = read_buffer;
 232         }
 233
 234         n = read_unbuffered(f,read_buffer+read_buffer_len,n);
 235         read_buffer_len += n;
 236 }
 237
 238
 239 /* do a buffered read from fd. don't return until all N bytes
 240    have been read. If all N can't be read then exit with an error */
 241 static void readfd(int fd,char *buffer,int N)
 242 {
 243         int  ret;
 244         int total=0;
 245
 246         if (read_buffer_len < N && N < 1024) {
 247                 read_check(buffer_f_in);
 248         }
 249
 250         while (total < N) {
 251                 if (read_buffer_len > 0 && buffer_f_in == fd) {
 252                         ret = MIN(read_buffer_len,N-total);
 253                         memcpy(buffer+total,read_buffer_p,ret);
 254                         read_buffer_p += ret;
 255                         read_buffer_len -= ret;
 256                         total += ret;
 257                         continue;
 258                 }
 259
 260                 io_flush();
 261
 262                 ret = read_unbuffered(fd,buffer + total,N-total);
 263                 total += ret;
 264         }
 265 }
 266
 267
 268 int32 read_int(int f)
 269 {
 270         char b[4];
 271         readfd(f,b,4);
 272         total_read += 4;
 273         return IVAL(b,0);
 274 }
 275
 276 int64 read_longint(int f)
 277 {
 278         extern int remote_version;
 279         int64 ret;
 280         char b[8];
 281         ret = read_int(f);
 282
 283         if ((int32)ret != (int32)0xffffffff) return ret;
 284
 285 #ifdef NO_INT64
 286         rprintf(FERROR,"Integer overflow - attempted 64 bit offset\n");
 287         exit_cleanup(1);
 288 #else
 289         if (remote_version >= 16) {
 290                 readfd(f,b,8);
 291                 total_read += 8;
 292                 ret = IVAL(b,0) | (((int64)IVAL(b,4))<<32);
 293         }
 294 #endif
 295
 296         return ret;
 297 }
 298
 299 void read_buf(int f,char *buf,int len)
 300 {
 301         readfd(f,buf,len);
 302         total_read += len;
 303 }
 304
 305 void read_sbuf(int f,char *buf,int len)
 306 {
 307         read_buf(f,buf,len);
 308         buf[len] = 0;
 309 }
 310
 311 unsigned char read_byte(int f)
 312 {
 313         unsigned char c;
 314         read_buf(f,(char *)&c,1);
 315         return c;
 316 }
 317
 318
 319
 320 /* write len bytes to fd, possibly reading from buffer_f_in if set
 321    in order to unclog the pipe. don't return until all len
 322    bytes have been written */
 323 static void writefd_unbuffered(int fd,char *buf,int len)
 324 {
 325         int total = 0;
 326         fd_set w_fds, r_fds;
 327         int fd_count, count;
 328         struct timeval tv;
 329         int reading;
 330
 331         reading = (buffer_f_in != -1 && read_buffer_len < MAX_READ_BUFFER);
 332
 333         while (total < len) {
 334                 FD_ZERO(&w_fds);
 335                 FD_ZERO(&r_fds);
 336                 FD_SET(fd,&w_fds);
 337                 fd_count = fd+1;
 338
 339                 if (reading) {
 340                         FD_SET(buffer_f_in,&r_fds);
 341                         if (buffer_f_in > fd)
 342                                 fd_count = buffer_f_in+1;
 343                 }
 344
 345                 tv.tv_sec = io_timeout;
 346                 tv.tv_usec = 0;
 347
 348                 count = select(fd_count,
 349                                reading?&r_fds:NULL,
 350                                &w_fds,NULL,
 351                                io_timeout?&tv:NULL);
 352
 353                 if (count <= 0) {
 354                         check_timeout();
 355                         continue;
 356                 }
 357
 358                 if (FD_ISSET(fd, &w_fds)) {
 359                         int ret = write(fd,buf+total,len-total);
 360
 361                         if (ret == -1 && errno == EINTR) {
 362                                 continue;
 363                         }
 364
 365                         if (ret <= 0) {
 366                                 rprintf(FERROR,"erroring writing %d bytes - exiting\n", len);
 367                                 exit_cleanup(1);
 368                         }
 369
 370                         total += ret;
 371                         if (io_timeout)
 372                                 last_io = time(NULL);
 373                         continue;
 374                 }
 375
 376                 if (reading && FD_ISSET(buffer_f_in, &r_fds)) {
 377                         read_check(buffer_f_in);
 378                 }
 379         }
 380 }
 381
 382
 383 static char *io_buffer;
 384 static int io_buffer_count;
 385
 386 void io_start_buffering(int fd)
 387 {
 388         if (io_buffer) return;
 389         multiplex_out_fd = fd;
 390         io_buffer = (char *)malloc(IO_BUFFER_SIZE+4);
 391         if (!io_buffer) out_of_memory("writefd");
 392         io_buffer_count = 0;
 393
 394         /* leave room for the multiplex header in case it's needed */
 395         io_buffer += 4;
 396 }
 397
 398 void io_flush(void)
 399 {
 400         int fd = multiplex_out_fd;
 401         if (!io_buffer_count) return;
 402
 403         if (io_multiplexing_out) {
 404                 SIVAL(io_buffer-4, 0, (MPLEX_BASE<<24) + io_buffer_count);
 405                 writefd_unbuffered(fd, io_buffer-4, io_buffer_count+4);
 406         } else {
 407                 writefd_unbuffered(fd, io_buffer, io_buffer_count);
 408         }
 409         io_buffer_count = 0;
 410 }
 411
 412 void io_end_buffering(int fd)
 413 {
 414         io_flush();
 415         if (!io_multiplexing_out) {
 416                 free(io_buffer-4);
 417                 io_buffer = NULL;
 418         }
 419 }
 420
 421 static void writefd(int fd,char *buf,int len)
 422 {
 423         if (!io_buffer) {
 424                 writefd_unbuffered(fd, buf, len);
 425                 return;
 426         }
 427
 428         while (len) {
 429                 int n = MIN(len, IO_BUFFER_SIZE-io_buffer_count);
 430                 if (n > 0) {
 431                         memcpy(io_buffer+io_buffer_count, buf, n);
 432                         buf += n;
 433                         len -= n;
 434                         io_buffer_count += n;
 435                 }
 436
 437                 if (io_buffer_count == IO_BUFFER_SIZE) io_flush();
 438         }
 439 }
 440
 441
 442 void write_int(int f,int32 x)
 443 {
 444         char b[4];
 445         SIVAL(b,0,x);
 446         writefd(f,b,4);
 447         total_written += 4;
 448 }
 449
 450 void write_longint(int f, int64 x)
 451 {
 452         extern int remote_version;
 453         char b[8];
 454
 455         if (remote_version < 16 || x <= 0x7FFFFFFF) {
 456                 write_int(f, (int)x);
 457                 return;
 458         }
 459
 460         write_int(f, -1);
 461         SIVAL(b,0,(x&0xFFFFFFFF));
 462         SIVAL(b,4,((x>>32)&0xFFFFFFFF));
 463
 464         writefd(f,b,8);
 465         total_written += 8;
 466 }
 467
 468 void write_buf(int f,char *buf,int len)
 469 {
 470         writefd(f,buf,len);
 471         total_written += len;
 472 }
 473
 474 /* write a string to the connection */
 475 void write_sbuf(int f,char *buf)
 476 {
 477         write_buf(f, buf, strlen(buf));
 478 }
 479
 480
 481 void write_byte(int f,unsigned char c)
 482 {
 483         write_buf(f,(char *)&c,1);
 484 }
 485
 486 int read_line(int f, char *buf, int maxlen)
 487 {
 488         eof_error = 0;
 489
 490         while (maxlen) {
 491                 buf[0] = 0;
 492                 read_buf(f, buf, 1);
 493                 if (buf[0] == 0) return 0;
 494                 if (buf[0] == '\n') {
 495                         buf[0] = 0;
 496                         break;
 497                 }
 498                 if (buf[0] != '\r') {
 499                         buf++;
 500                         maxlen--;
 501                 }
 502         }
 503         if (maxlen == 0) {
 504                 *buf = 0;
 505                 return 0;
 506         }
 507
 508         eof_error = 1;
 509
 510         return 1;
 511 }
 512
 513
 514 void io_printf(int fd, const char *format, ...)
 515 {
 516         va_list ap;
 517         char buf[1024];
 518         int len;
 519
 520         va_start(ap, format);
 521         len = vslprintf(buf, sizeof(buf)-1, format, ap);
 522         va_end(ap);
 523
 524         if (len < 0) exit_cleanup(1);
 525
 526         write_sbuf(fd, buf);
 527 }
 528
 529
 530 /* setup for multiplexing an error stream with the data stream */
 531 void io_start_multiplex_out(int fd)
 532 {
 533         multiplex_out_fd = fd;
 534         io_flush();
 535         io_start_buffering(fd);
 536         io_multiplexing_out = 1;
 537 }
 538
 539 /* setup for multiplexing an error stream with the data stream */
 540 void io_start_multiplex_in(int fd)
 541 {
 542         multiplex_in_fd = fd;
 543         io_flush();
 544         if (read_buffer_len) {
 545                 fprintf(stderr,"ERROR: data in read buffer at mplx start\n");
 546                 exit_cleanup(1);
 547         }
 548
 549         io_multiplexing_in = 1;
 550 }
 551
 552 /* write an message to the error stream */
 553 int io_multiplex_write(int f, char *buf, int len)
 554 {
 555         if (!io_multiplexing_out) return 0;
 556
 557         io_flush();
 558
 559         SIVAL(io_buffer-4, 0, ((MPLEX_BASE + f)<<24) + len);
 560         memcpy(io_buffer, buf, len);
 561
 562         writefd_unbuffered(multiplex_out_fd, io_buffer-4, len+4);
 563         return 1;
 564 }
 565
 566 void io_close_input(int fd)
 567 {
 568         buffer_f_in = -1;
 569 }