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
  36 extern int verbose;
  37 extern int io_timeout;
  38
  39 int64 write_total(void)
  40 {
  41         return total_written;
  42 }
  43
  44 int64 read_total(void)
  45 {
  46         return total_read;
  47 }
  48
  49 static int buffer_f_in = -1;
  50
  51 void setup_readbuffer(int f_in)
  52 {
  53         buffer_f_in = f_in;
  54 }
  55
  56 static void check_timeout(void)
  57 {
  58         time_t t;
  59
  60         if (!io_timeout) return;
  61
  62         if (!last_io) {
  63                 last_io = time(NULL);
  64                 return;
  65         }
  66
  67         t = time(NULL);
  68
  69         if (last_io && io_timeout && (t-last_io)>io_timeout) {
  70                 rprintf(FERROR,"read timeout after %d second - exiting\n",
  71                         (int)(t-last_io));
  72                 exit_cleanup(1);
  73         }
  74 }
  75
  76
  77 static char *read_buffer;
  78 static char *read_buffer_p;
  79 static int read_buffer_len;
  80 static int read_buffer_size;
  81
  82 /* read from a socket with IO timeout. return the number of
  83    bytes read. If no bytes can be read then exit, never return
  84    a number <= 0 */
  85 static int read_timeout(int fd, char *buf, int len)
  86 {
  87         int n, ret=0;
  88
  89         io_flush();
  90
  91         while (ret == 0) {
  92                 fd_set fds;
  93                 struct timeval tv;
  94
  95                 FD_ZERO(&fds);
  96                 FD_SET(fd, &fds);
  97                 tv.tv_sec = io_timeout;
  98                 tv.tv_usec = 0;
  99
 100                 if (select(fd+1, &fds, NULL, NULL,
 101                            io_timeout?&tv:NULL) != 1) {
 102                         check_timeout();
 103                         continue;
 104                 }
 105
 106                 n = read(fd, buf, len);
 107
 108                 if (n > 0) {
 109                         buf += n;
 110                         len -= n;
 111                         ret += n;
 112                         if (io_timeout)
 113                                 last_io = time(NULL);
 114                         continue;
 115                 }
 116
 117                 if (n == -1 && errno == EINTR) {
 118                         continue;
 119                 }
 120
 121                 if (n == 0) {
 122                         rprintf(FERROR,"EOF in read_timeout\n");
 123                         exit_cleanup(1);
 124                 }
 125
 126                 rprintf(FERROR,"read error: %s\n", strerror(errno));
 127                 exit_cleanup(1);
 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 handing 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(1);
 180                 }
 181
 182                 if (remaining > sizeof(line)-1) {
 183                         rprintf(FERROR,"multiplexing overflow %d\n\n",
 184                                 remaining);
 185                         exit_cleanup(1);
 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                 if (!read_buffer)
 224                         read_buffer = (char *)malloc(read_buffer_size);
 225                 else
 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         total_read += 4;
 270         return IVAL(b,0);
 271 }
 272
 273 int64 read_longint(int f)
 274 {
 275         extern int remote_version;
 276         int64 ret;
 277         char b[8];
 278         ret = read_int(f);
 279
 280         if ((int32)ret != (int32)0xffffffff) return ret;
 281
 282 #ifdef NO_INT64
 283         rprintf(FERROR,"Integer overflow - attempted 64 bit offset\n");
 284         exit_cleanup(1);
 285 #else
 286         if (remote_version >= 16) {
 287                 readfd(f,b,8);
 288                 total_read += 8;
 289                 ret = IVAL(b,0) | (((int64)IVAL(b,4))<<32);
 290         }
 291 #endif
 292
 293         return ret;
 294 }
 295
 296 void read_buf(int f,char *buf,int len)
 297 {
 298         readfd(f,buf,len);
 299         total_read += len;
 300 }
 301
 302 void read_sbuf(int f,char *buf,int len)
 303 {
 304         read_buf(f,buf,len);
 305         buf[len] = 0;
 306 }
 307
 308 unsigned char read_byte(int f)
 309 {
 310         unsigned char c;
 311         read_buf(f,(char *)&c,1);
 312         return c;
 313 }
 314
 315
 316
 317 /* write len bytes to fd, possibly reading from buffer_f_in if set
 318    in order to unclog the pipe. don't return until all len
 319    bytes have been written */
 320 static void writefd_unbuffered(int fd,char *buf,int len)
 321 {
 322         int total = 0;
 323         fd_set w_fds, r_fds;
 324         int fd_count, count;
 325         struct timeval tv;
 326         int reading;
 327
 328         reading = (buffer_f_in != -1 && read_buffer_len < MAX_READ_BUFFER);
 329
 330         while (total < len) {
 331                 FD_ZERO(&w_fds);
 332                 FD_ZERO(&r_fds);
 333                 FD_SET(fd,&w_fds);
 334                 fd_count = fd+1;
 335
 336                 if (reading) {
 337                         FD_SET(buffer_f_in,&r_fds);
 338                         if (buffer_f_in > fd)
 339                                 fd_count = buffer_f_in+1;
 340                 }
 341
 342                 tv.tv_sec = io_timeout;
 343                 tv.tv_usec = 0;
 344
 345                 count = select(fd_count,
 346                                reading?&r_fds:NULL,
 347                                &w_fds,NULL,
 348                                io_timeout?&tv:NULL);
 349
 350                 if (count <= 0) {
 351                         check_timeout();
 352                         continue;
 353                 }
 354
 355                 if (FD_ISSET(fd, &w_fds)) {
 356                         int ret = write(fd,buf+total,len-total);
 357
 358                         if (ret == -1 && errno == EINTR) {
 359                                 continue;
 360                         }
 361
 362                         if (ret <= 0) {
 363                                 rprintf(FERROR,"erroring writing %d bytes - exiting\n", len);
 364                                 exit_cleanup(1);
 365                         }
 366
 367                         total += ret;
 368                         if (io_timeout)
 369                                 last_io = time(NULL);
 370                         continue;
 371                 }
 372
 373                 if (reading && FD_ISSET(buffer_f_in, &r_fds)) {
 374                         read_check(buffer_f_in);
 375                 }
 376         }
 377 }
 378
 379
 380 static char *io_buffer;
 381 static int io_buffer_count;
 382
 383 void io_start_buffering(int fd)
 384 {
 385         if (io_buffer) return;
 386         multiplex_out_fd = fd;
 387         io_buffer = (char *)malloc(IO_BUFFER_SIZE+4);
 388         if (!io_buffer) out_of_memory("writefd");
 389         io_buffer_count = 0;
 390
 391         /* leave room for the multiplex header in case it's needed */
 392         io_buffer += 4;
 393 }
 394
 395 void io_flush(void)
 396 {
 397         int fd = multiplex_out_fd;
 398         if (!io_buffer_count) return;
 399
 400         if (io_multiplexing_out) {
 401                 SIVAL(io_buffer-4, 0, (MPLEX_BASE<<24) + io_buffer_count);
 402                 writefd_unbuffered(fd, io_buffer-4, io_buffer_count+4);
 403         } else {
 404                 writefd_unbuffered(fd, io_buffer, io_buffer_count);
 405         }
 406         io_buffer_count = 0;
 407 }
 408
 409 void io_end_buffering(int fd)
 410 {
 411         io_flush();
 412         if (!io_multiplexing_out) {
 413                 free(io_buffer-4);
 414                 io_buffer = NULL;
 415         }
 416 }
 417
 418 static void writefd(int fd,char *buf,int len)
 419 {
 420         if (!io_buffer) {
 421                 writefd_unbuffered(fd, buf, len);
 422                 return;
 423         }
 424
 425         while (len) {
 426                 int n = MIN(len, IO_BUFFER_SIZE-io_buffer_count);
 427                 if (n > 0) {
 428                         memcpy(io_buffer+io_buffer_count, buf, n);
 429                         buf += n;
 430                         len -= n;
 431                         io_buffer_count += n;
 432                 }
 433
 434                 if (io_buffer_count == IO_BUFFER_SIZE) io_flush();
 435         }
 436 }
 437
 438
 439 void write_int(int f,int32 x)
 440 {
 441         char b[4];
 442         SIVAL(b,0,x);
 443         writefd(f,b,4);
 444         total_written += 4;
 445 }
 446
 447 void write_longint(int f, int64 x)
 448 {
 449         extern int remote_version;
 450         char b[8];
 451
 452         if (remote_version < 16 || x <= 0x7FFFFFFF) {
 453                 write_int(f, (int)x);
 454                 return;
 455         }
 456
 457         write_int(f, -1);
 458         SIVAL(b,0,(x&0xFFFFFFFF));
 459         SIVAL(b,4,((x>>32)&0xFFFFFFFF));
 460
 461         writefd(f,b,8);
 462         total_written += 8;
 463 }
 464
 465 void write_buf(int f,char *buf,int len)
 466 {
 467         writefd(f,buf,len);
 468         total_written += len;
 469 }
 470
 471 /* write a string to the connection */
 472 void write_sbuf(int f,char *buf)
 473 {
 474         write_buf(f, buf, strlen(buf));
 475 }
 476
 477
 478 void write_byte(int f,unsigned char c)
 479 {
 480         write_buf(f,(char *)&c,1);
 481 }
 482
 483 int read_line(int f, char *buf, int maxlen)
 484 {
 485         while (maxlen) {
 486                 read_buf(f, buf, 1);
 487                 if (buf[0] == '\n') {
 488                         buf[0] = 0;
 489                         break;
 490                 }
 491                 if (buf[0] != '\r') {
 492                         buf++;
 493                         maxlen--;
 494                 }
 495         }
 496         if (maxlen == 0) {
 497                 *buf = 0;
 498                 return 0;
 499         }
 500         return 1;
 501 }
 502
 503
 504 void io_printf(int fd, const char *format, ...)
 505 {
 506         va_list ap;
 507         char buf[1024];
 508         int len;
 509
 510         va_start(ap, format);
 511         len = vslprintf(buf, sizeof(buf)-1, format, ap);
 512         va_end(ap);
 513
 514         if (len < 0) exit_cleanup(1);
 515
 516         write_sbuf(fd, buf);
 517 }
 518
 519
 520 /* setup for multiplexing an error stream with the data stream */
 521 void io_start_multiplex_out(int fd)
 522 {
 523         multiplex_out_fd = fd;
 524         io_flush();
 525         io_start_buffering(fd);
 526         io_multiplexing_out = 1;
 527 }
 528
 529 /* setup for multiplexing an error stream with the data stream */
 530 void io_start_multiplex_in(int fd)
 531 {
 532         multiplex_in_fd = fd;
 533         io_flush();
 534         if (read_buffer_len) {
 535                 fprintf(stderr,"ERROR: data in read buffer at mplx start\n");
 536                 exit_cleanup(1);
 537         }
 538
 539         io_multiplexing_in = 1;
 540 }
 541
 542 /* write an message to the error stream */
 543 int io_multiplex_write(int f, char *buf, int len)
 544 {
 545         if (!io_multiplexing_out) return 0;
 546
 547         io_flush();
 548
 549         SIVAL(io_buffer-4, 0, ((MPLEX_BASE + f)<<24) + len);
 550         memcpy(io_buffer, buf, len);
 551
 552         writefd_unbuffered(multiplex_out_fd, io_buffer-4, len+4);
 553         return 1;
 554 }
 555
 556 void io_close_input(int fd)
 557 {
 558         buffer_f_in = -1;
 559 }