restore/symtab.c

   1 /*
   2  *      Ported to Linux's Second Extended File System as part of the
   3  *      dump and restore backup suit
   4  *      Remy Card <card@Linux.EU.Org>, 1994-1997
   5  *      Stelian Pop <pop@noos.fr>, 1999-2000
   6  *      Stelian Pop <pop@noos.fr> - Alcôve <www.alcove.fr>, 2000
   7  */
   8
   9 /*
  10  * Copyright (c) 1983, 1993
  11  *      The Regents of the University of California.  All rights reserved.
  12  *
  13  * Redistribution and use in source and binary forms, with or without
  14  * modification, are permitted provided that the following conditions
  15  * are met:
  16  * 1. Redistributions of source code must retain the above copyright
  17  *    notice, this list of conditions and the following disclaimer.
  18  * 2. Redistributions in binary form must reproduce the above copyright
  19  *    notice, this list of conditions and the following disclaimer in the
  20  *    documentation and/or other materials provided with the distribution.
  21  * 3. All advertising materials mentioning features or use of this software
  22  *    must display the following acknowledgement:
  23  *      This product includes software developed by the University of
  24  *      California, Berkeley and its contributors.
  25  * 4. Neither the name of the University nor the names of its contributors
  26  *    may be used to endorse or promote products derived from this software
  27  *    without specific prior written permission.
  28  *
  29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  39  * SUCH DAMAGE.
  40  */
  41
  42 #ifndef lint
  43 static const char rcsid[] =
  44         "$Id: symtab.c,v 1.11 2000/12/04 15:43:17 stelian Exp $";
  45 #endif /* not lint */
  46
  47 /*
  48  * These routines maintain the symbol table which tracks the state
  49  * of the file system being restored. They provide lookup by either
  50  * name or inode number. They also provide for creation, deletion,
  51  * and renaming of entries. Because of the dynamic nature of pathnames,
  52  * names should not be saved, but always constructed just before they
  53  * are needed, by calling "myname".
  54  */
  55
  56 #include <sys/param.h>
  57 #include <sys/stat.h>
  58
  59 #ifdef  __linux__
  60 #include <sys/time.h>
  61 #include <linux/ext2_fs.h>
  62 #include <bsdcompat.h>
  63 #else   /* __linux__ */
  64 #include <ufs/ufs/dinode.h>
  65 #endif  /* __linux__ */
  66
  67 #include <errno.h>
  68 #include <compaterr.h>
  69 #include <fcntl.h>
  70 #include <stdio.h>
  71 #include <stdlib.h>
  72 #include <string.h>
  73 #include <unistd.h>
  74
  75 #ifdef  __linux__
  76 #include <ext2fs/ext2fs.h>
  77 #endif
  78
  79 #include "restore.h"
  80 #include "extern.h"
  81
  82 /*
  83  * The following variables define the inode symbol table.
  84  * The primary hash table is dynamically allocated based on
  85  * the number of inodes in the file system (maxino), scaled by
  86  * HASHFACTOR. The variable "entry" points to the hash table;
  87  * the variable "entrytblsize" indicates its size (in entries).
  88  */
  89 #define HASHFACTOR 5
  90 static struct entry **entry;
  91 static long entrytblsize;
  92
  93 static void              addino __P((ino_t, struct entry *));
  94 static struct entry     *lookupparent __P((char *));
  95 static void              removeentry __P((struct entry *));
  96
  97 /*
  98  * Look up an entry by inode number
  99  */
 100 struct entry *
 101 lookupino(ino_t inum)
 102 {
 103         register struct entry *ep;
 104
 105         if (inum < WINO || inum >= maxino)
 106                 return (NULL);
 107         for (ep = entry[inum % entrytblsize]; ep != NULL; ep = ep->e_next)
 108                 if (ep->e_ino == inum)
 109                         return (ep);
 110         return (NULL);
 111 }
 112
 113 /*
 114  * Add an entry into the entry table
 115  */
 116 static void
 117 addino(ino_t inum, struct entry *np)
 118 {
 119         struct entry **epp;
 120
 121         if (inum < WINO || inum >= maxino)
 122                 panic("addino: out of range %d\n", inum);
 123         epp = &entry[inum % entrytblsize];
 124         np->e_ino = inum;
 125         np->e_next = *epp;
 126         *epp = np;
 127         if (dflag)
 128                 for (np = np->e_next; np != NULL; np = np->e_next)
 129                         if (np->e_ino == inum)
 130                                 badentry(np, "duplicate inum");
 131 }
 132
 133 /*
 134  * Delete an entry from the entry table
 135  */
 136 void
 137 deleteino(ino_t inum)
 138 {
 139         register struct entry *next;
 140         struct entry **prev;
 141
 142         if (inum < WINO || inum >= maxino)
 143                 panic("deleteino: out of range %d\n", inum);
 144         prev = &entry[inum % entrytblsize];
 145         for (next = *prev; next != NULL; next = next->e_next) {
 146                 if (next->e_ino == inum) {
 147                         next->e_ino = 0;
 148                         *prev = next->e_next;
 149                         return;
 150                 }
 151                 prev = &next->e_next;
 152         }
 153         panic("deleteino: %d not found\n", inum);
 154 }
 155
 156 /*
 157  * Look up an entry by name
 158  */
 159 struct entry *
 160 lookupname(char *name)
 161 {
 162         register struct entry *ep;
 163         register char *np, *cp;
 164         char buf[MAXPATHLEN];
 165
 166         cp = name;
 167         for (ep = lookupino(ROOTINO); ep != NULL; ep = ep->e_entries) {
 168                 for (np = buf; *cp != '/' && *cp != '\0' &&
 169                                 np < &buf[sizeof(buf)]; )
 170                         *np++ = *cp++;
 171                 if (np == &buf[sizeof(buf)])
 172                         break;
 173                 *np = '\0';
 174                 for ( ; ep != NULL; ep = ep->e_sibling)
 175                         if (strcmp(ep->e_name, buf) == 0)
 176                                 break;
 177                 if (ep == NULL)
 178                         break;
 179                 if (*cp++ == '\0')
 180                         return (ep);
 181         }
 182         return (NULL);
 183 }
 184
 185 /*
 186  * Look up the parent of a pathname
 187  */
 188 static struct entry *
 189 lookupparent(char *name)
 190 {
 191         struct entry *ep;
 192         char *tailindex;
 193
 194         tailindex = strrchr(name, '/');
 195         if (tailindex == NULL)
 196                 return (NULL);
 197         *tailindex = '\0';
 198         ep = lookupname(name);
 199         *tailindex = '/';
 200         if (ep == NULL)
 201                 return (NULL);
 202         if (ep->e_type != NODE)
 203                 panic("%s is not a directory\n", name);
 204         return (ep);
 205 }
 206
 207 /*
 208  * Determine the current pathname of a node or leaf
 209  */
 210 char *
 211 myname(struct entry *ep)
 212 {
 213         register char *cp;
 214         static char namebuf[MAXPATHLEN];
 215
 216         for (cp = &namebuf[MAXPATHLEN - 2]; cp > &namebuf[ep->e_namlen]; ) {
 217                 cp -= ep->e_namlen;
 218                 memmove(cp, ep->e_name, (size_t)ep->e_namlen);
 219                 if (ep == lookupino(ROOTINO))
 220                         return (cp);
 221                 *(--cp) = '/';
 222                 ep = ep->e_parent;
 223         }
 224         panic("%s: pathname too long\n", cp);
 225         return(cp);
 226 }
 227
 228 /*
 229  * Unused symbol table entries are linked together on a free list
 230  * headed by the following pointer.
 231  */
 232 static struct entry *freelist = NULL;
 233
 234 /*
 235  * add an entry to the symbol table
 236  */
 237 struct entry *
 238 addentry(char *name, ino_t inum, int type)
 239 {
 240         register struct entry *np, *ep;
 241
 242         if (freelist != NULL) {
 243                 np = freelist;
 244                 freelist = np->e_next;
 245                 memset(np, 0, sizeof(struct entry));
 246         } else {
 247                 np = (struct entry *)calloc(1, sizeof(struct entry));
 248                 if (np == NULL)
 249                         errx(1, "no memory to extend symbol table");
 250         }
 251         np->e_type = type & ~LINK;
 252         ep = lookupparent(name);
 253         if (ep == NULL) {
 254                 if (inum != ROOTINO || lookupino(ROOTINO) != NULL)
 255                         panic("bad name to addentry %s\n", name);
 256                 np->e_name = savename(name);
 257                 np->e_namlen = strlen(name);
 258                 np->e_parent = np;
 259                 addino(ROOTINO, np);
 260                 return (np);
 261         }
 262         np->e_name = savename(strrchr(name, '/') + 1);
 263         np->e_namlen = strlen(np->e_name);
 264         np->e_parent = ep;
 265         np->e_sibling = ep->e_entries;
 266         ep->e_entries = np;
 267         if (type & LINK) {
 268                 ep = lookupino(inum);
 269                 if (ep == NULL)
 270                         panic("link to non-existent name\n");
 271                 np->e_ino = inum;
 272                 np->e_links = ep->e_links;
 273                 ep->e_links = np;
 274         } else if (inum != 0) {
 275                 if (lookupino(inum) != NULL)
 276                         panic("duplicate entry\n");
 277                 addino(inum, np);
 278         }
 279         return (np);
 280 }
 281
 282 /*
 283  * delete an entry from the symbol table
 284  */
 285 void
 286 freeentry(struct entry *ep)
 287 {
 288         register struct entry *np;
 289         ino_t inum;
 290
 291         if (ep->e_flags != REMOVED)
 292                 badentry(ep, "not marked REMOVED");
 293         if (ep->e_type == NODE) {
 294                 if (ep->e_links != NULL)
 295                         badentry(ep, "freeing referenced directory");
 296                 if (ep->e_entries != NULL)
 297                         badentry(ep, "freeing non-empty directory");
 298         }
 299         if (ep->e_ino != 0) {
 300                 np = lookupino(ep->e_ino);
 301                 if (np == NULL)
 302                         badentry(ep, "lookupino failed");
 303                 if (np == ep) {
 304                         inum = ep->e_ino;
 305                         deleteino(inum);
 306                         if (ep->e_links != NULL)
 307                                 addino(inum, ep->e_links);
 308                 } else {
 309                         for (; np != NULL; np = np->e_links) {
 310                                 if (np->e_links == ep) {
 311                                         np->e_links = ep->e_links;
 312                                         break;
 313                                 }
 314                         }
 315                         if (np == NULL)
 316                                 badentry(ep, "link not found");
 317                 }
 318         }
 319         removeentry(ep);
 320         freename(ep->e_name);
 321         ep->e_next = freelist;
 322         freelist = ep;
 323 }
 324
 325 /*
 326  * Relocate an entry in the tree structure
 327  */
 328 void
 329 moveentry(struct entry *ep, char *newname)
 330 {
 331         struct entry *np;
 332         char *cp;
 333
 334         np = lookupparent(newname);
 335         if (np == NULL)
 336                 badentry(ep, "cannot move ROOT");
 337         if (np != ep->e_parent) {
 338                 removeentry(ep);
 339                 ep->e_parent = np;
 340                 ep->e_sibling = np->e_entries;
 341                 np->e_entries = ep;
 342         }
 343         cp = strrchr(newname, '/') + 1;
 344         freename(ep->e_name);
 345         ep->e_name = savename(cp);
 346         ep->e_namlen = strlen(cp);
 347         if (strcmp(gentempname(ep), ep->e_name) == 0)
 348                 ep->e_flags |= TMPNAME;
 349         else
 350                 ep->e_flags &= ~TMPNAME;
 351 }
 352
 353 /*
 354  * Remove an entry in the tree structure
 355  */
 356 static void
 357 removeentry(struct entry *ep)
 358 {
 359         register struct entry *np;
 360
 361         np = ep->e_parent;
 362         if (np->e_entries == ep) {
 363                 np->e_entries = ep->e_sibling;
 364         } else {
 365                 for (np = np->e_entries; np != NULL; np = np->e_sibling) {
 366                         if (np->e_sibling == ep) {
 367                                 np->e_sibling = ep->e_sibling;
 368                                 break;
 369                         }
 370                 }
 371                 if (np == NULL)
 372                         badentry(ep, "cannot find entry in parent list");
 373         }
 374 }
 375
 376 /*
 377  * Table of unused string entries, sorted by length.
 378  *
 379  * Entries are allocated in STRTBLINCR sized pieces so that names
 380  * of similar lengths can use the same entry. The value of STRTBLINCR
 381  * is chosen so that every entry has at least enough space to hold
 382  * a "struct strtbl" header. Thus every entry can be linked onto an
 383  * appropriate free list.
 384  *
 385  * NB. The macro "allocsize" below assumes that "struct strhdr"
 386  *     has a size that is a power of two.
 387  */
 388 struct strhdr {
 389         struct strhdr *next;
 390 };
 391
 392 #define STRTBLINCR      (sizeof(struct strhdr))
 393 #define allocsize(size) (((size) + 1 + STRTBLINCR - 1) & ~(STRTBLINCR - 1))
 394
 395 static struct strhdr strtblhdr[allocsize(MAXNAMLEN) / STRTBLINCR];
 396
 397 /*
 398  * Allocate space for a name. It first looks to see if it already
 399  * has an appropriate sized entry, and if not allocates a new one.
 400  */
 401 char *
 402 savename(char *name)
 403 {
 404         struct strhdr *np;
 405         long len;
 406         char *cp;
 407
 408         if (name == NULL)
 409                 panic("bad name\n");
 410         len = strlen(name);
 411         np = strtblhdr[len / STRTBLINCR].next;
 412         if (np != NULL) {
 413                 strtblhdr[len / STRTBLINCR].next = np->next;
 414                 cp = (char *)np;
 415         } else {
 416                 cp = malloc((unsigned)allocsize(len));
 417                 if (cp == NULL)
 418                         errx(1, "no space for string table");
 419         }
 420         (void) strcpy(cp, name);
 421         return (cp);
 422 }
 423
 424 /*
 425  * Free space for a name. The resulting entry is linked onto the
 426  * appropriate free list.
 427  */
 428 void
 429 freename(char *name)
 430 {
 431         struct strhdr *tp, *np;
 432
 433         tp = &strtblhdr[strlen(name) / STRTBLINCR];
 434         np = (struct strhdr *)name;
 435         np->next = tp->next;
 436         tp->next = np;
 437 }
 438
 439 /*
 440  * Useful quantities placed at the end of a dumped symbol table.
 441  */
 442 struct symtableheader {
 443         int32_t volno;
 444         int32_t stringsize;
 445         int32_t entrytblsize;
 446         time_t  dumptime;
 447         time_t  dumpdate;
 448         ino_t   maxino;
 449         int32_t ntrec;
 450 };
 451
 452 /*
 453  * dump a snapshot of the symbol table
 454  */
 455 void
 456 dumpsymtable(char *filename, long checkpt)
 457 {
 458         register struct entry *ep, *tep;
 459         register ino_t i;
 460         struct entry temp, *tentry;
 461         long mynum = 1, stroff = 0;
 462         FILE *fd;
 463         struct symtableheader hdr;
 464
 465         Vprintf(stdout, "Check pointing the restore\n");
 466         if (Nflag)
 467                 return;
 468         if ((fd = fopen(filename, "w")) == NULL) {
 469                 warn("fopen");
 470                 panic("cannot create save file %s for symbol table\n",
 471                         filename);
 472         }
 473         clearerr(fd);
 474         /*
 475          * Assign indices to each entry
 476          * Write out the string entries
 477          */
 478         for (i = WINO; i <= maxino; i++) {
 479                 for (ep = lookupino(i); ep != NULL; ep = ep->e_links) {
 480                         ep->e_index = mynum++;
 481                         (void) fwrite(ep->e_name, sizeof(char),
 482                                (int)allocsize(ep->e_namlen), fd);
 483                 }
 484         }
 485         /*
 486          * Convert pointers to indexes, and output
 487          */
 488         tep = &temp;
 489         stroff = 0;
 490         for (i = WINO; i <= maxino; i++) {
 491                 for (ep = lookupino(i); ep != NULL; ep = ep->e_links) {
 492                         memmove(tep, ep, sizeof(struct entry));
 493                         tep->e_name = (char *)stroff;
 494                         stroff += allocsize(ep->e_namlen);
 495                         tep->e_parent = (struct entry *)ep->e_parent->e_index;
 496                         if (ep->e_links != NULL)
 497                                 tep->e_links =
 498                                         (struct entry *)ep->e_links->e_index;
 499                         if (ep->e_sibling != NULL)
 500                                 tep->e_sibling =
 501                                         (struct entry *)ep->e_sibling->e_index;
 502                         if (ep->e_entries != NULL)
 503                                 tep->e_entries =
 504                                         (struct entry *)ep->e_entries->e_index;
 505                         if (ep->e_next != NULL)
 506                                 tep->e_next =
 507                                         (struct entry *)ep->e_next->e_index;
 508                         (void) fwrite((char *)tep, sizeof(struct entry), 1, fd);
 509                 }
 510         }
 511         /*
 512          * Convert entry pointers to indexes, and output
 513          */
 514         for (i = 0; i < entrytblsize; i++) {
 515                 if (entry[i] == NULL)
 516                         tentry = NULL;
 517                 else
 518                         tentry = (struct entry *)entry[i]->e_index;
 519                 (void) fwrite((char *)&tentry, sizeof(struct entry *), 1, fd);
 520         }
 521         hdr.volno = checkpt;
 522         hdr.maxino = maxino;
 523         hdr.entrytblsize = entrytblsize;
 524         hdr.stringsize = stroff;
 525         hdr.dumptime = dumptime;
 526         hdr.dumpdate = dumpdate;
 527         hdr.ntrec = ntrec;
 528         (void) fwrite((char *)&hdr, sizeof(struct symtableheader), 1, fd);
 529         if (ferror(fd)) {
 530                 warn("fwrite");
 531                 panic("output error to file %s writing symbol table\n",
 532                         filename);
 533         }
 534         (void) fclose(fd);
 535 }
 536
 537 /*
 538  * Initialize a symbol table from a file
 539  */
 540 void
 541 initsymtable(char *filename)
 542 {
 543         char *base;
 544         long tblsize;
 545         register struct entry *ep;
 546         struct entry *baseep, *lep;
 547         struct symtableheader hdr;
 548         struct stat stbuf;
 549         register long i;
 550         int fd;
 551
 552         Vprintf(stdout, "Initialize symbol table.\n");
 553         if (filename == NULL) {
 554                 entrytblsize = maxino / HASHFACTOR;
 555                 entry = (struct entry **)
 556                         calloc((unsigned)entrytblsize, sizeof(struct entry *));
 557                 if (entry == (struct entry **)NULL)
 558                         errx(1, "no memory for entry table");
 559                 ep = addentry(".", ROOTINO, NODE);
 560                 ep->e_flags |= NEW;
 561                 return;
 562         }
 563         if ((fd = open(filename, O_RDONLY, 0)) < 0) {
 564                 warn("open");
 565                 errx(1, "cannot open symbol table file %s", filename);
 566         }
 567         if (fstat(fd, &stbuf) < 0) {
 568                 warn("stat");
 569                 errx(1, "cannot stat symbol table file %s", filename);
 570         }
 571         tblsize = stbuf.st_size - sizeof(struct symtableheader);
 572         base = calloc(sizeof(char), (unsigned)tblsize);
 573         if (base == NULL)
 574                 errx(1, "cannot allocate space for symbol table");
 575         if (read(fd, base, (int)tblsize) < 0 ||
 576             read(fd, (char *)&hdr, sizeof(struct symtableheader)) < 0) {
 577                 warn("read");
 578                 errx(1, "cannot read symbol table file %s", filename);
 579         }
 580         switch (command) {
 581         case 'r':
 582                 /*
 583                  * For normal continuation, insure that we are using
 584                  * the next incremental tape
 585                  */
 586                 if (hdr.dumpdate != dumptime)
 587                         errx(1, "Incremental tape too %s",
 588                                 (hdr.dumpdate < dumptime) ? "low" : "high");
 589                 break;
 590         case 'R':
 591                 /*
 592                  * For restart, insure that we are using the same tape
 593                  */
 594                 curfile.action = SKIP;
 595                 dumptime = hdr.dumptime;
 596                 dumpdate = hdr.dumpdate;
 597                 if (!bflag)
 598                         newtapebuf(hdr.ntrec);
 599                 getvol(hdr.volno);
 600                 break;
 601         default:
 602                 panic("initsymtable called from command %c\n", command);
 603                 break;
 604         }
 605         maxino = hdr.maxino;
 606         entrytblsize = hdr.entrytblsize;
 607         entry = (struct entry **)
 608                 (base + tblsize - (entrytblsize * sizeof(struct entry *)));
 609         baseep = (struct entry *)(base + hdr.stringsize - sizeof(struct entry));
 610         lep = (struct entry *)entry;
 611         for (i = 0; i < entrytblsize; i++) {
 612                 if (entry[i] == NULL)
 613                         continue;
 614                 entry[i] = &baseep[(long)entry[i]];
 615         }
 616         for (ep = &baseep[1]; ep < lep; ep++) {
 617                 ep->e_name = base + (long)ep->e_name;
 618                 ep->e_parent = &baseep[(long)ep->e_parent];
 619                 if (ep->e_sibling != NULL)
 620                         ep->e_sibling = &baseep[(long)ep->e_sibling];
 621                 if (ep->e_links != NULL)
 622                         ep->e_links = &baseep[(long)ep->e_links];
 623                 if (ep->e_entries != NULL)
 624                         ep->e_entries = &baseep[(long)ep->e_entries];
 625                 if (ep->e_next != NULL)
 626                         ep->e_next = &baseep[(long)ep->e_next];
 627         }
 628 }