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 1.14 2001/04/24 10:59:13 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 <config.h>
  57 #include <sys/param.h>
  58 #include <sys/stat.h>
  59
  60 #ifdef  __linux__
  61 #include <sys/time.h>
  62 #include <time.h>
  63 #include <linux/ext2_fs.h>
  64 #include <bsdcompat.h>
  65 #else   /* __linux__ */
  66 #include <ufs/ufs/dinode.h>
  67 #endif  /* __linux__ */
  68
  69 #include <errno.h>
  70 #include <compaterr.h>
  71 #include <fcntl.h>
  72 #include <stdio.h>
  73 #include <stdlib.h>
  74 #include <string.h>
  75 #include <unistd.h>
  76
  77 #ifdef  __linux__
  78 #include <ext2fs/ext2fs.h>
  79 #endif
  80
  81 #include "restore.h"
  82 #include "extern.h"
  83
  84 /*
  85  * The following variables define the inode symbol table.
  86  * The primary hash table is dynamically allocated based on
  87  * the number of inodes in the file system (maxino), scaled by
  88  * HASHFACTOR. The variable "entry" points to the hash table;
  89  * the variable "entrytblsize" indicates its size (in entries).
  90  */
  91 #define HASHFACTOR 5
  92 static struct entry **entry;
  93 static long entrytblsize;
  94
  95 static void              addino __P((dump_ino_t, struct entry *));
  96 static struct entry     *lookupparent __P((char *));
  97 static void              removeentry __P((struct entry *));
  98
  99 /*
 100  * Look up an entry by inode number
 101  */
 102 struct entry *
 103 lookupino(dump_ino_t inum)
 104 {
 105         register struct entry *ep;
 106
 107         if (inum < WINO || inum >= maxino)
 108                 return (NULL);
 109         for (ep = entry[inum % entrytblsize]; ep != NULL; ep = ep->e_next)
 110                 if (ep->e_ino == inum)
 111                         return (ep);
 112         return (NULL);
 113 }
 114
 115 /*
 116  * Add an entry into the entry table
 117  */
 118 static void
 119 addino(dump_ino_t inum, struct entry *np)
 120 {
 121         struct entry **epp;
 122
 123         if (inum < WINO || inum >= maxino)
 124                 panic("addino: out of range %d\n", inum);
 125         epp = &entry[inum % entrytblsize];
 126         np->e_ino = inum;
 127         np->e_next = *epp;
 128         *epp = np;
 129         if (dflag)
 130                 for (np = np->e_next; np != NULL; np = np->e_next)
 131                         if (np->e_ino == inum)
 132                                 badentry(np, "duplicate inum");
 133 }
 134
 135 /*
 136  * Delete an entry from the entry table
 137  */
 138 void
 139 deleteino(dump_ino_t inum)
 140 {
 141         register struct entry *next;
 142         struct entry **prev;
 143
 144         if (inum < WINO || inum >= maxino)
 145                 panic("deleteino: out of range %d\n", inum);
 146         prev = &entry[inum % entrytblsize];
 147         for (next = *prev; next != NULL; next = next->e_next) {
 148                 if (next->e_ino == inum) {
 149                         next->e_ino = 0;
 150                         *prev = next->e_next;
 151                         return;
 152                 }
 153                 prev = &next->e_next;
 154         }
 155         panic("deleteino: %d not found\n", inum);
 156 }
 157
 158 /*
 159  * Look up an entry by name
 160  */
 161 struct entry *
 162 lookupname(char *name)
 163 {
 164         register struct entry *ep;
 165         register char *np, *cp;
 166         char buf[MAXPATHLEN];
 167
 168         cp = name;
 169         for (ep = lookupino(ROOTINO); ep != NULL; ep = ep->e_entries) {
 170                 for (np = buf; *cp != '/' && *cp != '\0' &&
 171                                 np < &buf[sizeof(buf)]; )
 172                         *np++ = *cp++;
 173                 if (np == &buf[sizeof(buf)])
 174                         break;
 175                 *np = '\0';
 176                 for ( ; ep != NULL; ep = ep->e_sibling)
 177                         if (strcmp(ep->e_name, buf) == 0)
 178                                 break;
 179                 if (ep == NULL)
 180                         break;
 181                 if (*cp++ == '\0')
 182                         return (ep);
 183         }
 184         return (NULL);
 185 }
 186
 187 /*
 188  * Look up the parent of a pathname
 189  */
 190 static struct entry *
 191 lookupparent(char *name)
 192 {
 193         struct entry *ep;
 194         char *tailindex;
 195
 196         tailindex = strrchr(name, '/');
 197         if (tailindex == NULL)
 198                 return (NULL);
 199         *tailindex = '\0';
 200         ep = lookupname(name);
 201         *tailindex = '/';
 202         if (ep == NULL)
 203                 return (NULL);
 204         if (ep->e_type != NODE)
 205                 panic("%s is not a directory\n", name);
 206         return (ep);
 207 }
 208
 209 /*
 210  * Determine the current pathname of a node or leaf
 211  */
 212 char *
 213 myname(struct entry *ep)
 214 {
 215         register char *cp;
 216         static char namebuf[MAXPATHLEN];
 217
 218         for (cp = &namebuf[MAXPATHLEN - 2]; cp > &namebuf[ep->e_namlen]; ) {
 219                 cp -= ep->e_namlen;
 220                 memmove(cp, ep->e_name, (size_t)ep->e_namlen);
 221                 if (ep == lookupino(ROOTINO))
 222                         return (cp);
 223                 *(--cp) = '/';
 224                 ep = ep->e_parent;
 225         }
 226         panic("%s: pathname too long\n", cp);
 227         return(cp);
 228 }
 229
 230 /*
 231  * Unused symbol table entries are linked together on a free list
 232  * headed by the following pointer.
 233  */
 234 static struct entry *freelist = NULL;
 235
 236 /*
 237  * add an entry to the symbol table
 238  */
 239 struct entry *
 240 addentry(char *name, dump_ino_t inum, int type)
 241 {
 242         register struct entry *np, *ep;
 243
 244         if (freelist != NULL) {
 245                 np = freelist;
 246                 freelist = np->e_next;
 247                 memset(np, 0, sizeof(struct entry));
 248         } else {
 249                 np = (struct entry *)calloc(1, sizeof(struct entry));
 250                 if (np == NULL)
 251                         errx(1, "no memory to extend symbol table");
 252         }
 253         np->e_type = type & ~LINK;
 254         ep = lookupparent(name);
 255         if (ep == NULL) {
 256                 if (inum != ROOTINO || lookupino(ROOTINO) != NULL)
 257                         panic("bad name to addentry %s\n", name);
 258                 np->e_name = savename(name);
 259                 np->e_namlen = strlen(name);
 260                 np->e_parent = np;
 261                 addino(ROOTINO, np);
 262                 return (np);
 263         }
 264         np->e_name = savename(strrchr(name, '/') + 1);
 265         np->e_namlen = strlen(np->e_name);
 266         np->e_parent = ep;
 267         np->e_sibling = ep->e_entries;
 268         ep->e_entries = np;
 269         if (type & LINK) {
 270                 ep = lookupino(inum);
 271                 if (ep == NULL)
 272                         panic("link to non-existent name\n");
 273                 np->e_ino = inum;
 274                 np->e_links = ep->e_links;
 275                 ep->e_links = np;
 276         } else if (inum != 0) {
 277                 if (lookupino(inum) != NULL)
 278                         panic("duplicate entry\n");
 279                 addino(inum, np);
 280         }
 281         return (np);
 282 }
 283
 284 /*
 285  * delete an entry from the symbol table
 286  */
 287 void
 288 freeentry(struct entry *ep)
 289 {
 290         register struct entry *np;
 291         dump_ino_t inum;
 292
 293         if (ep->e_flags != REMOVED)
 294                 badentry(ep, "not marked REMOVED");
 295         if (ep->e_type == NODE) {
 296                 if (ep->e_links != NULL)
 297                         badentry(ep, "freeing referenced directory");
 298                 if (ep->e_entries != NULL)
 299                         badentry(ep, "freeing non-empty directory");
 300         }
 301         if (ep->e_ino != 0) {
 302                 np = lookupino(ep->e_ino);
 303                 if (np == NULL)
 304                         badentry(ep, "lookupino failed");
 305                 if (np == ep) {
 306                         inum = ep->e_ino;
 307                         deleteino(inum);
 308                         if (ep->e_links != NULL)
 309                                 addino(inum, ep->e_links);
 310                 } else {
 311                         for (; np != NULL; np = np->e_links) {
 312                                 if (np->e_links == ep) {
 313                                         np->e_links = ep->e_links;
 314                                         break;
 315                                 }
 316                         }
 317                         if (np == NULL)
 318                                 badentry(ep, "link not found");
 319                 }
 320         }
 321         removeentry(ep);
 322         freename(ep->e_name);
 323         ep->e_next = freelist;
 324         freelist = ep;
 325 }
 326
 327 /*
 328  * Relocate an entry in the tree structure
 329  */
 330 void
 331 moveentry(struct entry *ep, char *newname)
 332 {
 333         struct entry *np;
 334         char *cp;
 335
 336         np = lookupparent(newname);
 337         if (np == NULL)
 338                 badentry(ep, "cannot move ROOT");
 339         if (np != ep->e_parent) {
 340                 removeentry(ep);
 341                 ep->e_parent = np;
 342                 ep->e_sibling = np->e_entries;
 343                 np->e_entries = ep;
 344         }
 345         cp = strrchr(newname, '/') + 1;
 346         freename(ep->e_name);
 347         ep->e_name = savename(cp);
 348         ep->e_namlen = strlen(cp);
 349         if (strcmp(gentempname(ep), ep->e_name) == 0)
 350                 ep->e_flags |= TMPNAME;
 351         else
 352                 ep->e_flags &= ~TMPNAME;
 353 }
 354
 355 /*
 356  * Remove an entry in the tree structure
 357  */
 358 static void
 359 removeentry(struct entry *ep)
 360 {
 361         register struct entry *np;
 362
 363         np = ep->e_parent;
 364         if (np->e_entries == ep) {
 365                 np->e_entries = ep->e_sibling;
 366         } else {
 367                 for (np = np->e_entries; np != NULL; np = np->e_sibling) {
 368                         if (np->e_sibling == ep) {
 369                                 np->e_sibling = ep->e_sibling;
 370                                 break;
 371                         }
 372                 }
 373                 if (np == NULL)
 374                         badentry(ep, "cannot find entry in parent list");
 375         }
 376 }
 377
 378 /*
 379  * Table of unused string entries, sorted by length.
 380  *
 381  * Entries are allocated in STRTBLINCR sized pieces so that names
 382  * of similar lengths can use the same entry. The value of STRTBLINCR
 383  * is chosen so that every entry has at least enough space to hold
 384  * a "struct strtbl" header. Thus every entry can be linked onto an
 385  * appropriate free list.
 386  *
 387  * NB. The macro "allocsize" below assumes that "struct strhdr"
 388  *     has a size that is a power of two.
 389  */
 390 struct strhdr {
 391         struct strhdr *next;
 392 };
 393
 394 #define STRTBLINCR      (sizeof(struct strhdr))
 395 #define allocsize(size) (((size) + 1 + STRTBLINCR - 1) & ~(STRTBLINCR - 1))
 396
 397 static struct strhdr strtblhdr[allocsize(MAXNAMLEN) / STRTBLINCR];
 398
 399 /*
 400  * Allocate space for a name. It first looks to see if it already
 401  * has an appropriate sized entry, and if not allocates a new one.
 402  */
 403 char *
 404 savename(char *name)
 405 {
 406         struct strhdr *np;
 407         long len;
 408         char *cp;
 409
 410         if (name == NULL)
 411                 panic("bad name\n");
 412         len = strlen(name);
 413         np = strtblhdr[len / STRTBLINCR].next;
 414         if (np != NULL) {
 415                 strtblhdr[len / STRTBLINCR].next = np->next;
 416                 cp = (char *)np;
 417         } else {
 418                 cp = malloc((unsigned)allocsize(len));
 419                 if (cp == NULL)
 420                         errx(1, "no space for string table");
 421         }
 422         (void) strcpy(cp, name);
 423         return (cp);
 424 }
 425
 426 /*
 427  * Free space for a name. The resulting entry is linked onto the
 428  * appropriate free list.
 429  */
 430 void
 431 freename(char *name)
 432 {
 433         struct strhdr *tp, *np;
 434
 435         tp = &strtblhdr[strlen(name) / STRTBLINCR];
 436         np = (struct strhdr *)name;
 437         np->next = tp->next;
 438         tp->next = np;
 439 }
 440
 441 /*
 442  * Useful quantities placed at the end of a dumped symbol table.
 443  */
 444 struct symtableheader {
 445         int32_t volno;
 446         int32_t stringsize;
 447         int32_t entrytblsize;
 448         time_t  dumptime;
 449         time_t  dumpdate;
 450         dump_ino_t maxino;
 451         int32_t ntrec;
 452 };
 453
 454 /*
 455  * dump a snapshot of the symbol table
 456  */
 457 void
 458 dumpsymtable(char *filename, long checkpt)
 459 {
 460         register struct entry *ep, *tep;
 461         register dump_ino_t i;
 462         struct entry temp, *tentry;
 463         long mynum = 1, stroff = 0;
 464         FILE *fd;
 465         struct symtableheader hdr;
 466
 467         Vprintf(stdout, "Check pointing the restore\n");
 468         if (Nflag)
 469                 return;
 470         if ((fd = fopen(filename, "w")) == NULL) {
 471                 warn("fopen");
 472                 panic("cannot create save file %s for symbol table\n",
 473                         filename);
 474         }
 475         clearerr(fd);
 476         /*
 477          * Assign indices to each entry
 478          * Write out the string entries
 479          */
 480         for (i = WINO; i <= maxino; i++) {
 481                 for (ep = lookupino(i); ep != NULL; ep = ep->e_links) {
 482                         ep->e_index = mynum++;
 483                         (void) fwrite(ep->e_name, sizeof(char),
 484                                (int)allocsize(ep->e_namlen), fd);
 485                 }
 486         }
 487         /*
 488          * Convert pointers to indexes, and output
 489          */
 490         tep = &temp;
 491         stroff = 0;
 492         for (i = WINO; i <= maxino; i++) {
 493                 for (ep = lookupino(i); ep != NULL; ep = ep->e_links) {
 494                         memmove(tep, ep, sizeof(struct entry));
 495                         tep->e_name = (char *)stroff;
 496                         stroff += allocsize(ep->e_namlen);
 497                         tep->e_parent = (struct entry *)ep->e_parent->e_index;
 498                         if (ep->e_links != NULL)
 499                                 tep->e_links =
 500                                         (struct entry *)ep->e_links->e_index;
 501                         if (ep->e_sibling != NULL)
 502                                 tep->e_sibling =
 503                                         (struct entry *)ep->e_sibling->e_index;
 504                         if (ep->e_entries != NULL)
 505                                 tep->e_entries =
 506                                         (struct entry *)ep->e_entries->e_index;
 507                         if (ep->e_next != NULL)
 508                                 tep->e_next =
 509                                         (struct entry *)ep->e_next->e_index;
 510                         (void) fwrite((char *)tep, sizeof(struct entry), 1, fd);
 511                 }
 512         }
 513         /*
 514          * Convert entry pointers to indexes, and output
 515          */
 516         for (i = 0; i < entrytblsize; i++) {
 517                 if (entry[i] == NULL)
 518                         tentry = NULL;
 519                 else
 520                         tentry = (struct entry *)entry[i]->e_index;
 521                 (void) fwrite((char *)&tentry, sizeof(struct entry *), 1, fd);
 522         }
 523         hdr.volno = checkpt;
 524         hdr.maxino = maxino;
 525         hdr.entrytblsize = entrytblsize;
 526         hdr.stringsize = stroff;
 527         hdr.dumptime = dumptime;
 528         hdr.dumpdate = dumpdate;
 529         hdr.ntrec = ntrec;
 530         (void) fwrite((char *)&hdr, sizeof(struct symtableheader), 1, fd);
 531         if (ferror(fd)) {
 532                 warn("fwrite");
 533                 panic("output error to file %s writing symbol table\n",
 534                         filename);
 535         }
 536         (void) fclose(fd);
 537 }
 538
 539 /*
 540  * Initialize a symbol table from a file
 541  */
 542 void
 543 initsymtable(char *filename)
 544 {
 545         char *base;
 546         long tblsize;
 547         register struct entry *ep;
 548         struct entry *baseep, *lep;
 549         struct symtableheader hdr;
 550         struct stat stbuf;
 551         register long i;
 552         int fd;
 553
 554         Vprintf(stdout, "Initialize symbol table.\n");
 555         if (filename == NULL) {
 556                 entrytblsize = maxino / HASHFACTOR;
 557                 entry = (struct entry **)
 558                         calloc((unsigned)entrytblsize, sizeof(struct entry *));
 559                 if (entry == (struct entry **)NULL)
 560                         errx(1, "no memory for entry table");
 561                 ep = addentry(".", ROOTINO, NODE);
 562                 ep->e_flags |= NEW;
 563                 return;
 564         }
 565         if ((fd = open(filename, O_RDONLY, 0)) < 0) {
 566                 warn("open");
 567                 errx(1, "cannot open symbol table file %s", filename);
 568         }
 569         if (fstat(fd, &stbuf) < 0) {
 570                 warn("stat");
 571                 errx(1, "cannot stat symbol table file %s", filename);
 572         }
 573         tblsize = stbuf.st_size - sizeof(struct symtableheader);
 574         base = calloc(sizeof(char), (unsigned)tblsize);
 575         if (base == NULL)
 576                 errx(1, "cannot allocate space for symbol table");
 577         if (read(fd, base, (int)tblsize) < 0 ||
 578             read(fd, (char *)&hdr, sizeof(struct symtableheader)) < 0) {
 579                 warn("read");
 580                 errx(1, "cannot read symbol table file %s", filename);
 581         }
 582         switch (command) {
 583         case 'r':
 584                 /*
 585                  * For normal continuation, insure that we are using
 586                  * the next incremental tape
 587                  */
 588                 if (hdr.dumpdate != dumptime)
 589                         errx(1, "Incremental tape too %s",
 590                                 (hdr.dumpdate < dumptime) ? "low" : "high");
 591                 break;
 592         case 'R':
 593                 /*
 594                  * For restart, insure that we are using the same tape
 595                  */
 596                 curfile.action = SKIP;
 597                 dumptime = hdr.dumptime;
 598                 dumpdate = hdr.dumpdate;
 599                 if (!bflag)
 600                         newtapebuf(hdr.ntrec);
 601                 getvol(hdr.volno);
 602                 break;
 603         default:
 604                 panic("initsymtable called from command %c\n", command);
 605                 break;
 606         }
 607         maxino = hdr.maxino;
 608         entrytblsize = hdr.entrytblsize;
 609         entry = (struct entry **)
 610                 (base + tblsize - (entrytblsize * sizeof(struct entry *)));
 611         baseep = (struct entry *)(base + hdr.stringsize - sizeof(struct entry));
 612         lep = (struct entry *)entry;
 613         for (i = 0; i < entrytblsize; i++) {
 614                 if (entry[i] == NULL)
 615                         continue;
 616                 entry[i] = &baseep[(long)entry[i]];
 617         }
 618         for (ep = &baseep[1]; ep < lep; ep++) {
 619                 ep->e_name = base + (long)ep->e_name;
 620                 ep->e_parent = &baseep[(long)ep->e_parent];
 621                 if (ep->e_sibling != NULL)
 622                         ep->e_sibling = &baseep[(long)ep->e_sibling];
 623                 if (ep->e_links != NULL)
 624                         ep->e_links = &baseep[(long)ep->e_links];
 625                 if (ep->e_entries != NULL)
 626                         ep->e_entries = &baseep[(long)ep->e_entries];
 627                 if (ep->e_next != NULL)
 628                         ep->e_next = &baseep[(long)ep->e_next];
 629         }
 630 }