Dogcows Code - chaz/tar/blob - src/diffarch.c

   1 /* Diff files from a tar archive.
   2    Copyright (C) 1988 Free Software Foundation
   3
   4 This file is part of GNU Tar.
   5
   6 GNU Tar is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Tar is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Tar; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20 /*
  21  * Diff files from a tar archive.
  22  *
  23  * Written 30 April 1987 by John Gilmore, ihnp4!hoptoad!gnu.
  24  */
  25
  26 #include <stdio.h>
  27 #include <errno.h>
  28 #ifndef STDC_HEADERS
  29 extern int errno;
  30 #endif
  31 #include <sys/types.h>
  32
  33 #ifdef BSD42
  34 #include <sys/file.h>
  35 #else
  36 #ifndef V7
  37 #include <fcntl.h>
  38 #endif
  39 #endif
  40
  41 #ifndef NO_MTIO
  42 #include <sys/ioctl.h>
  43 #include <sys/mtio.h>
  44 #endif
  45
  46 #include "tar.h"
  47 #include "port.h"
  48 #include "rmt.h"
  49
  50 #ifndef S_ISLNK
  51 #define lstat stat
  52 #endif
  53
  54 extern char *valloc();
  55
  56 extern union record *head;              /* Points to current tape header */
  57 extern struct stat hstat;               /* Stat struct corresponding */
  58 extern int head_standard;               /* Tape header is in ANSI format */
  59
  60 void decode_header();
  61 void diff_sparse_files();
  62 void fill_in_sparse_array();
  63 void fl_read();
  64 long from_oct();
  65 int do_stat();
  66 extern void print_header();
  67 int read_header();
  68 void saverec();
  69 void sigh();
  70 extern void skip_file();
  71 extern void skip_extended_headers();
  72 int wantbytes();
  73
  74 extern FILE *msg_file;
  75
  76 int now_verifying = 0;          /* Are we verifying at the moment? */
  77
  78 int     diff_fd;                /* Descriptor of file we're diffing */
  79
  80 char    *diff_buf = 0;          /* Pointer to area for reading
  81                                            file contents into */
  82
  83 char    *diff_dir;              /* Directory contents for LF_DUMPDIR */
  84
  85 int different = 0;
  86
  87 /*struct sp_array *sparsearray;
  88 int             sp_ar_size = 10;*/
  89 /*
  90  * Initialize for a diff operation
  91  */
  92 void
  93 diff_init()
  94 {
  95         /*NOSTRICT*/
  96         diff_buf = (char *) valloc((unsigned)blocksize);
  97         if (!diff_buf) {
  98                 msg("could not allocate memory for diff buffer of %d bytes",
  99                         blocksize);
 100                 exit(EX_ARGSBAD);
 101         }
 102 }
 103
 104 /*
 105  * Diff a file against the archive.
 106  */
 107 void
 108 diff_archive()
 109 {
 110         register char *data;
 111         int check, namelen;
 112         int err;
 113         long offset;
 114         struct stat filestat;
 115         int compare_chunk();
 116         int compare_dir();
 117         int no_op();
 118 #ifndef __MSDOS__
 119         dev_t   dev;
 120         ino_t   ino;
 121 #endif
 122         char *get_dir_contents();
 123         long from_oct();
 124
 125         errno = EPIPE;                  /* FIXME, remove perrors */
 126
 127         saverec(&head);                 /* Make sure it sticks around */
 128         userec(head);                   /* And go past it in the archive */
 129         decode_header(head, &hstat, &head_standard, 1); /* Snarf fields */
 130
 131         /* Print the record from 'head' and 'hstat' */
 132         if (f_verbose) {
 133                 if(now_verifying)
 134                         fprintf(msg_file,"Verify ");
 135                 print_header();
 136         }
 137
 138         switch (head->header.linkflag) {
 139
 140         default:
 141                 msg("Unknown file type '%c' for %s, diffed as normal file",
 142                         head->header.linkflag, head->header.name);
 143                 /* FALL THRU */
 144
 145         case LF_OLDNORMAL:
 146         case LF_NORMAL:
 147         case LF_SPARSE:
 148         case LF_CONTIG:
 149                 /*
 150                  * Appears to be a file.
 151                  * See if it's really a directory.
 152                  */
 153                 namelen = strlen(head->header.name)-1;
 154                 if (head->header.name[namelen] == '/')
 155                         goto really_dir;
 156
 157
 158                 if(do_stat(&filestat)) {
 159                         if (head->header.isextended)
 160                                 skip_extended_headers();
 161                         skip_file((long)hstat.st_size);
 162                         different++;
 163                         goto quit;
 164                 }
 165
 166                 if (!S_ISREG(filestat.st_mode)) {
 167                         fprintf(msg_file, "%s: not a regular file\n",
 168                                 head->header.name);
 169                         skip_file((long)hstat.st_size);
 170                         different++;
 171                         goto quit;
 172                 }
 173
 174                 filestat.st_mode &= 07777;
 175                 if (filestat.st_mode != hstat.st_mode)
 176                         sigh("mode");
 177                 if (filestat.st_uid  != hstat.st_uid)
 178                         sigh("uid");
 179                 if (filestat.st_gid  != hstat.st_gid)
 180                         sigh("gid");
 181                 if (filestat.st_mtime != hstat.st_mtime)
 182                         sigh("mod time");
 183                 if (head->header.linkflag != LF_SPARSE &&
 184                                 filestat.st_size != hstat.st_size) {
 185                         sigh("size");
 186                         skip_file((long)hstat.st_size);
 187                         goto quit;
 188                 }
 189
 190                 diff_fd = open(head->header.name, O_NDELAY|O_RDONLY|O_BINARY);
 191
 192                 if (diff_fd < 0 && !f_absolute_paths) {
 193                         char tmpbuf[NAMSIZ+2];
 194
 195                         tmpbuf[0]='/';
 196                         strcpy(&tmpbuf[1],head->header.name);
 197                         diff_fd=open(tmpbuf, O_NDELAY|O_RDONLY);
 198                 }
 199                 if (diff_fd < 0) {
 200                         msg_perror("cannot open %s",head->header.name);
 201                         if (head->header.isextended)
 202                                 skip_extended_headers();
 203                         skip_file((long)hstat.st_size);
 204                         different++;
 205                         goto quit;
 206                 }
 207                 /*
 208                  * Need to treat sparse files completely differently here.
 209                  */
 210                 if (head->header.linkflag == LF_SPARSE)
 211                         diff_sparse_files(hstat.st_size);
 212                 else
 213                         wantbytes((long)(hstat.st_size),compare_chunk);
 214
 215                 check = close(diff_fd);
 216                 if (check < 0)
 217                         msg_perror("Error while closing %s",head->header.name);
 218
 219         quit:
 220                 break;
 221
 222 #ifndef __MSDOS__
 223         case LF_LINK:
 224                 if(do_stat(&filestat))
 225                         break;
 226                 dev = filestat.st_dev;
 227                 ino = filestat.st_ino;
 228                 err = stat(head->header.linkname, &filestat);
 229                 if (err < 0) {
 230                         if (errno==ENOENT) {
 231                                 fprintf(msg_file, "%s: does not exist\n",head->header.name);
 232                         } else {
 233                                 msg_perror("cannot stat file %s",head->header.name);
 234                         }
 235                         different++;
 236                         break;
 237                 }
 238                 if(filestat.st_dev!=dev || filestat.st_ino!=ino) {
 239                         fprintf(msg_file, "%s not linked to %s\n",head->header.name,head->header.linkname);
 240                         break;
 241                 }
 242                 break;
 243 #endif
 244
 245 #ifdef S_ISLNK
 246         case LF_SYMLINK:
 247         {
 248                 char linkbuf[NAMSIZ+3];
 249                 check = readlink(head->header.name, linkbuf,
 250                                  (sizeof linkbuf)-1);
 251
 252                 if (check < 0) {
 253                         if (errno == ENOENT) {
 254                                 fprintf(msg_file,
 255                                         "%s: no such file or directory\n",
 256                                         head->header.name);
 257                         } else {
 258                                 msg_perror("cannot read link %s",head->header.name);
 259                         }
 260                         different++;
 261                         break;
 262                 }
 263
 264                 linkbuf[check] = '\0';  /* Null-terminate it */
 265                 if (strncmp(head->header.linkname, linkbuf, check) != 0) {
 266                         fprintf(msg_file, "%s: symlink differs\n",
 267                                 head->header.linkname);
 268                         different++;
 269                 }
 270         }
 271                 break;
 272 #endif
 273
 274 #ifdef S_IFCHR
 275         case LF_CHR:
 276                 hstat.st_mode |= S_IFCHR;
 277                 goto check_node;
 278 #endif
 279
 280 #ifdef S_IFBLK
 281         /* If local system doesn't support block devices, use default case */
 282         case LF_BLK:
 283                 hstat.st_mode |= S_IFBLK;
 284                 goto check_node;
 285 #endif
 286
 287 #ifdef S_ISFIFO
 288         /* If local system doesn't support FIFOs, use default case */
 289         case LF_FIFO:
 290 #ifdef S_IFIFO
 291                 hstat.st_mode |= S_IFIFO;
 292 #endif
 293                 hstat.st_rdev = 0;              /* FIXME, do we need this? */
 294                 goto check_node;
 295 #endif
 296
 297         check_node:
 298                 /* FIXME, deal with umask */
 299                 if(do_stat(&filestat))
 300                         break;
 301                 if(hstat.st_rdev != filestat.st_rdev) {
 302                         fprintf(msg_file, "%s: device numbers changed\n", head->header.name);
 303                         different++;
 304                         break;
 305                 }
 306 #ifdef S_IFMT
 307                 if(hstat.st_mode != filestat.st_mode)
 308 #else /* POSIX lossage */
 309                 if((hstat.st_mode & 07777) != (filestat.st_mode & 07777))
 310 #endif
 311                 {
 312                         fprintf(msg_file, "%s: mode or device-type changed\n", head->header.name);
 313                         different++;
 314                         break;
 315                 }
 316                 break;
 317
 318         case LF_DUMPDIR:
 319                 data=diff_dir=get_dir_contents(head->header.name,0);
 320                 if (data) {
 321                         wantbytes((long)(hstat.st_size),compare_dir);
 322                         free(data);
 323                 } else
 324                         wantbytes((long)(hstat.st_size),no_op);
 325                 /* FALL THROUGH */
 326
 327         case LF_DIR:
 328                 /* Check for trailing / */
 329                 namelen = strlen(head->header.name)-1;
 330         really_dir:
 331                 while (namelen && head->header.name[namelen] == '/')
 332                         head->header.name[namelen--] = '\0';    /* Zap / */
 333
 334                 if(do_stat(&filestat))
 335                         break;
 336                 if(!S_ISDIR(filestat.st_mode)) {
 337                         fprintf(msg_file, "%s is no longer a directory\n",head->header.name);
 338                         different++;
 339                         break;
 340                 }
 341                 if((filestat.st_mode&07777) != (hstat.st_mode&07777))
 342                         sigh("mode");
 343                 break;
 344
 345         case LF_VOLHDR:
 346                 break;
 347
 348         case LF_MULTIVOL:
 349                 namelen = strlen(head->header.name)-1;
 350                 if (head->header.name[namelen] == '/')
 351                         goto really_dir;
 352
 353                 if(do_stat(&filestat))
 354                         break;
 355
 356                 if (!S_ISREG(filestat.st_mode)) {
 357                         fprintf(msg_file, "%s: not a regular file\n",
 358                                 head->header.name);
 359                         skip_file((long)hstat.st_size);
 360                         different++;
 361                         break;
 362                 }
 363
 364                 filestat.st_mode &= 07777;
 365                 offset = from_oct(1+12, head->header.offset);
 366                 if (filestat.st_size != hstat.st_size + offset) {
 367                         sigh("size");
 368                         skip_file((long)hstat.st_size);
 369                         different++;
 370                         break;
 371                 }
 372
 373                 diff_fd = open(head->header.name, O_NDELAY|O_RDONLY|O_BINARY);
 374
 375                 if (diff_fd < 0) {
 376                         msg_perror("cannot open file %s",head->header.name);
 377                         skip_file((long)hstat.st_size);
 378                         different++;
 379                         break;
 380                 }
 381                 err = lseek(diff_fd, offset, 0);
 382                 if(err!=offset) {
 383                         msg_perror("cannot seek to %ld in file %s",offset,head->header.name);
 384                         different++;
 385                         break;
 386                 }
 387
 388                 wantbytes((long)(hstat.st_size),compare_chunk);
 389
 390                 check = close(diff_fd);
 391                 if (check < 0) {
 392                         msg_perror("Error while closing %s",head->header.name);
 393                 }
 394                 break;
 395
 396         }
 397
 398         /* We don't need to save it any longer. */
 399         saverec((union record **) 0);   /* Unsave it */
 400 }
 401
 402 int
 403 compare_chunk(bytes,buffer)
 404 long bytes;
 405 char *buffer;
 406 {
 407         int err;
 408
 409         err=read(diff_fd,diff_buf,bytes);
 410         if(err!=bytes) {
 411                 if(err<0) {
 412                         msg_perror("can't read %s",head->header.name);
 413                 } else {
 414                         fprintf(msg_file,"%s: could only read %d of %d bytes\n",head->header.name,err,bytes);
 415                 }
 416                 different++;
 417                 return -1;
 418         }
 419         if(bcmp(buffer,diff_buf,bytes)) {
 420                 fprintf(msg_file, "%s: data differs\n",head->header.name);
 421                 different++;
 422                 return -1;
 423         }
 424         return 0;
 425 }
 426
 427 int
 428 compare_dir(bytes,buffer)
 429 long bytes;
 430 char *buffer;
 431 {
 432         if(bcmp(buffer,diff_dir,bytes)) {
 433                 fprintf(msg_file, "%s: data differs\n",head->header.name);
 434                 different++;
 435                 return -1;
 436         }
 437         diff_dir+=bytes;
 438         return 0;
 439 }
 440
 441 /*
 442  * Sigh about something that differs.
 443  */
 444 void
 445 sigh(what)
 446         char *what;
 447 {
 448
 449         fprintf(msg_file, "%s: %s differs\n",
 450                 head->header.name, what);
 451 }
 452
 453 void
 454 verify_volume()
 455 {
 456         int status;
 457 #ifdef MTIOCTOP
 458         struct mtop t;
 459         int er;
 460 #endif
 461
 462         if(!diff_buf)
 463                 diff_init();
 464 #ifdef MTIOCTOP
 465         t.mt_op = MTBSF;
 466         t.mt_count = 1;
 467         if((er=rmtioctl(archive,MTIOCTOP,&t))<0) {
 468                 if(errno!=EIO || (er=rmtioctl(archive,MTIOCTOP,&t))<0) {
 469 #endif
 470                         if(rmtlseek(archive,0L,0)!=0) {
 471                                 /* Lseek failed.  Try a different method */
 472                                 msg_perror("Couldn't rewind archive file for verify");
 473                                 return;
 474                         }
 475 #ifdef MTIOCTOP
 476                 }
 477         }
 478 #endif
 479         ar_reading=1;
 480         now_verifying = 1;
 481         fl_read();
 482         for(;;) {
 483                 status = read_header();
 484                 if(status==0) {
 485                         unsigned n;
 486
 487                         n=0;
 488                         do {
 489                                 n++;
 490                                 status=read_header();
 491                         } while(status==0);
 492                         msg("VERIFY FAILURE: %d invalid header%s detected!",n,n==1?"":"s");
 493                 }
 494                 if(status==2 || status==EOF)
 495                         break;
 496                 diff_archive();
 497         }
 498         ar_reading=0;
 499         now_verifying = 0;
 500
 501 }
 502
 503 int
 504 do_stat(statp)
 505 struct stat *statp;
 506 {
 507         int err;
 508
 509         err = f_follow_links ? stat(head->header.name, statp) : lstat(head->header.name, statp);
 510         if (err < 0) {
 511                 if (errno==ENOENT) {
 512                         fprintf(msg_file, "%s: does not exist\n",head->header.name);
 513                 } else
 514                         msg_perror("can't stat file %s",head->header.name);
 515 /*              skip_file((long)hstat.st_size);
 516                 different++;*/
 517                 return 1;
 518         } else
 519                 return 0;
 520 }
 521
 522 /*
 523  * JK
 524  * Diff'ing a sparse file with its counterpart on the tar file is a
 525  * bit of a different story than a normal file.  First, we must know
 526  * what areas of the file to skip through, i.e., we need to contruct
 527  * a sparsearray, which will hold all the information we need.  We must
 528  * compare small amounts of data at a time as we find it.
 529  */
 530
 531 void
 532 diff_sparse_files(filesize)
 533 int     filesize;
 534
 535 {
 536         int             sparse_ind = 0;
 537         char            *buf;
 538         int             buf_size = RECORDSIZE;
 539         union record    *datarec;
 540         int             err;
 541         long            numbytes;
 542 /*      int             amt_read = 0;*/
 543         int             size = filesize;
 544
 545         buf = (char *) malloc(buf_size * sizeof (char));
 546
 547         fill_in_sparse_array();
 548
 549
 550         while (size > 0) {
 551                 datarec = findrec();
 552                 if (!sparsearray[sparse_ind].numbytes)
 553                         break;
 554
 555                 /*
 556                  * 'numbytes' is nicer to write than
 557                  * 'sparsearray[sparse_ind].numbytes' all the time ...
 558                  */
 559                 numbytes = sparsearray[sparse_ind].numbytes;
 560
 561                 lseek(diff_fd, sparsearray[sparse_ind].offset, 0);
 562                 /*
 563                  * take care to not run out of room in our buffer
 564                  */
 565                 while (buf_size < numbytes) {
 566                         buf = (char *) realloc(buf, buf_size * 2 * sizeof(char));
 567                         buf_size *= 2;
 568                 }
 569                 while (numbytes > RECORDSIZE) {
 570                         if ((err = read(diff_fd, buf, RECORDSIZE)) != RECORDSIZE) {
 571                                 if (err < 0)
 572                                         msg_perror("can't read %s", head->header.name);
 573                                 else
 574                                         fprintf(msg_file, "%s: could only read %d of %d bytes\n",
 575                                                 err, numbytes);
 576                                 break;
 577                         }
 578                         if (bcmp(buf, datarec->charptr, RECORDSIZE)) {
 579                                 different++;
 580                                 break;
 581                         }
 582                         numbytes -= err;
 583                         size -= err;
 584                         userec(datarec);
 585                         datarec = findrec();
 586                 }
 587                 if ((err = read(diff_fd, buf, numbytes)) != numbytes) {
 588                         if (err < 0)
 589                                 msg_perror("can't read %s", head->header.name);
 590                         else
 591                                 fprintf(msg_file, "%s: could only read %d of %d bytes\n",
 592                                                 err, numbytes);
 593                         break;
 594                 }
 595
 596                 if (bcmp(buf, datarec->charptr, numbytes)) {
 597                         different++;
 598                         break;
 599                 }
 600 /*              amt_read += numbytes;
 601                 if (amt_read >= RECORDSIZE) {
 602                         amt_read = 0;
 603                         userec(datarec);
 604                         datarec = findrec();
 605                 }*/
 606                 userec(datarec);
 607                 sparse_ind++;
 608                 size -= numbytes;
 609         }
 610         /*
 611          * if the number of bytes read isn't the
 612          * number of bytes supposedly in the file,
 613          * they're different
 614          */
 615 /*      if (amt_read != filesize)
 616                 different++;*/
 617         userec(datarec);
 618         free(sparsearray);
 619         if (different)
 620                 fprintf(msg_file, "%s: data differs\n", head->header.name);
 621
 622 }
 623
 624 /*
 625  * JK
 626  * This routine should be used more often than it is ... look into
 627  * that.  Anyhow, what it does is translate the sparse information
 628  * on the header, and in any subsequent extended headers, into an
 629  * array of structures with true numbers, as opposed to character
 630  * strings.  It simply makes our life much easier, doing so many
 631  * comparisong and such.
 632  */
 633 void
 634 fill_in_sparse_array()
 635 {
 636         int     ind;
 637
 638         /*
 639          * allocate space for our scratch space; it's initially
 640          * 10 elements long, but can change in this routine if
 641          * necessary
 642          */
 643         sp_array_size = 10;
 644         sparsearray = (struct sp_array *) malloc(sp_array_size * sizeof(struct sp_array));
 645
 646         /*
 647          * there are at most five of these structures in the header
 648          * itself; read these in first
 649          */
 650         for (ind = 0; ind < SPARSE_IN_HDR; ind++) {
 651                 if (!head->header.sp[ind].numbytes)
 652                         break;
 653                 sparsearray[ind].offset =
 654                         from_oct(1+12, head->header.sp[ind].offset);
 655                 sparsearray[ind].numbytes =
 656                         from_oct(1+12, head->header.sp[ind].numbytes);
 657         }
 658         /*
 659          * if the header's extended, we gotta read in exhdr's till
 660          * we're done
 661          */
 662         if (head->header.isextended) {
 663             /* how far into the sparsearray we are 'so far' */
 664             static int so_far_ind = SPARSE_IN_HDR;
 665             union record *exhdr;
 666
 667             for (;;) {
 668                 exhdr = findrec();
 669                 for (ind = 0; ind < SPARSE_EXT_HDR; ind++) {
 670                         if (ind+so_far_ind > sp_array_size-1) {
 671                                 /*
 672                                  * we just ran out of room in our
 673                                  *  scratch area - realloc it
 674                                  */
 675                                 sparsearray = (struct sp_array *)
 676                                         realloc(sparsearray,
 677                                                 sp_array_size*2*sizeof(struct sp_array));
 678                                 sp_array_size *= 2;
 679                         }
 680                         /*
 681                          * convert the character strings into longs
 682                          */
 683                         sparsearray[ind+so_far_ind].offset =
 684                             from_oct(1+12, exhdr->ext_hdr.sp[ind].offset);
 685                         sparsearray[ind+so_far_ind].numbytes =
 686                             from_oct(1+12, exhdr->ext_hdr.sp[ind].numbytes);
 687                 }
 688                 /*
 689                  * if this is the last extended header for this
 690                  * file, we can stop
 691                  */
 692                 if (!exhdr->ext_hdr.isextended)
 693                         break;
 694                 else {
 695                         so_far_ind += SPARSE_EXT_HDR;
 696                         userec(exhdr);
 697                 }
 698             }
 699             /* be sure to skip past the last one  */
 700             userec(exhdr);
 701         }
 702 }