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 1.12 2000/12/21 11:14:54 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 <linux/ext2_fs.h>
  63 #include <bsdcompat.h>
  64 #else   /* __linux__ */
  65 #include <ufs/ufs/dinode.h>
  66 #endif  /* __linux__ */
  67
  68 #include <errno.h>
  69 #include <compaterr.h>
  70 #include <fcntl.h>
  71 #include <stdio.h>
  72 #include <stdlib.h>
  73 #include <string.h>
  74 #include <unistd.h>
  75
  76 #ifdef  __linux__
  77 #include <ext2fs/ext2fs.h>
  78 #endif
  79
  80 #include "restore.h"
  81 #include "extern.h"
  82
  83 /*
  84  * The following variables define the inode symbol table.
  85  * The primary hash table is dynamically allocated based on
  86  * the number of inodes in the file system (maxino), scaled by
  87  * HASHFACTOR. The variable "entry" points to the hash table;
  88  * the variable "entrytblsize" indicates its size (in entries).
  89  */
  90 #define HASHFACTOR 5
  91 static struct entry **entry;
  92 static long entrytblsize;
  93
  94 static void              addino __P((ino_t, struct entry *));
  95 static struct entry     *lookupparent __P((char *));
  96 static void              removeentry __P((struct entry *));
  97
  98 /*
  99  * Look up an entry by inode number
 100  */
 101 struct entry *
 102 lookupino(ino_t inum)
 103 {
 104         register struct entry *ep;
 105
 106         if (inum < WINO || inum >= maxino)
 107                 return (NULL);
 108         for (ep = entry[inum % entrytblsize]; ep != NULL; ep = ep->e_next)
 109                 if (ep->e_ino == inum)
 110                         return (ep);
 111         return (NULL);
 112 }
 113
 114 /*
 115  * Add an entry into the entry table
 116  */
 117 static void
 118 addino(ino_t inum, struct entry *np)
 119 {
 120         struct entry **epp;
 121
 122         if (inum < WINO || inum >= maxino)
 123                 panic("addino: out of range %d\n", inum);
 124         epp = &entry[inum % entrytblsize];
 125         np->e_ino = inum;
 126         np->e_next = *epp;
 127         *epp = np;
 128         if (dflag)
 129                 for (np = np->e_next; np != NULL; np = np->e_next)
 130                         if (np->e_ino == inum)
 131                                 badentry(np, "duplicate inum");
 132 }
 133
 134 /*
 135  * Delete an entry from the entry table
 136  */
 137 void
 138 deleteino(ino_t inum)
 139 {
 140         register struct entry *next;
 141         struct entry **prev;
 142
 143         if (inum < WINO || inum >= maxino)
 144                 panic("deleteino: out of range %d\n", inum);
 145         prev = &entry[inum % entrytblsize];
 146         for (next = *prev; next != NULL; next = next->e_next) {
 147                 if (next->e_ino == inum) {
 148                         next->e_ino = 0;
 149                         *prev = next->e_next;
 150                         return;
 151                 }
 152                 prev = &next->e_next;
 153         }
 154         panic("deleteino: %d not found\n", inum);
 155 }
 156
 157 /*
 158  * Look up an entry by name
 159  */
 160 struct entry *
 161 lookupname(char *name)
 162 {
 163         register struct entry *ep;
 164         register char *np, *cp;
 165         char buf[MAXPATHLEN];
 166
 167         cp = name;
 168         for (ep = lookupino(ROOTINO); ep != NULL; ep = ep->e_entries) {
 169                 for (np = buf; *cp != '/' && *cp != '\0' &&
 170                                 np < &buf[sizeof(buf)]; )
 171                         *np++ = *cp++;
 172                 if (np == &buf[sizeof(buf)])
 173                         break;
 174                 *np = '\0';
 175                 for ( ; ep != NULL; ep = ep->e_sibling)
 176                         if (strcmp(ep->e_name, buf) == 0)
 177                                 break;
 178                 if (ep == NULL)
 179                         break;
 180                 if (*cp++ == '\0')
 181                         return (ep);
 182         }
 183         return (NULL);
 184 }
 185
 186 /*
 187  * Look up the parent of a pathname
 188  */
 189 static struct entry *
 190 lookupparent(char *name)
 191 {
 192         struct entry *ep;
 193         char *tailindex;
 194
 195         tailindex = strrchr(name, '/');
 196         if (tailindex == NULL)
 197                 return (NULL);
 198         *tailindex = '\0';
 199         ep = lookupname(name);
 200         *tailindex = '/';
 201         if (ep == NULL)
 202                 return (NULL);
 203         if (ep->e_type != NODE)
 204                 panic("%s is not a directory\n", name);
 205         return (ep);
 206 }
 207
 208 /*
 209  * Determine the current pathname of a node or leaf
 210  */
 211 char *
 212 myname(struct entry *ep)
 213 {
 214         register char *cp;
 215         static char namebuf[MAXPATHLEN];
 216
 217         for (cp = &namebuf[MAXPATHLEN - 2]; cp > &namebuf[ep->e_namlen]; ) {
 218                 cp -= ep->e_namlen;
 219                 memmove(cp, ep->e_name, (size_t)ep->e_namlen);
 220                 if (ep == lookupino(ROOTINO))
 221                         return (cp);
 222                 *(--cp) = '/';
 223                 ep = ep->e_parent;
 224         }
 225         panic("%s: pathname too long\n", cp);
 226         return(cp);
 227 }
 228
 229 /*
 230  * Unused symbol table entries are linked together on a free list
 231  * headed by the following pointer.
 232  */
 233 static struct entry *freelist = NULL;
 234
 235 /*
 236  * add an entry to the symbol table
 237  */
 238 struct entry *
 239 addentry(char *name, ino_t inum, int type)
 240 {
 241         register struct entry *np, *ep;
 242
 243         if (freelist != NULL) {
 244                 np = freelist;
 245                 freelist = np->e_next;
 246                 memset(np, 0, sizeof(struct entry));
 247         } else {
 248                 np = (struct entry *)calloc(1, sizeof(struct entry));
 249                 if (np == NULL)
 250                         errx(1, "no memory to extend symbol table");
 251         }
 252         np->e_type = type & ~LINK;
 253         ep = lookupparent(name);
 254         if (ep == NULL) {
 255                 if (inum != ROOTINO || lookupino(ROOTINO) != NULL)
 256                         panic("bad name to addentry %s\n", name);
 257                 np->e_name = savename(name);
 258                 np->e_namlen = strlen(name);
 259                 np->e_parent = np;
 260                 addino(ROOTINO, np);
 261                 return (np);
 262         }
 263         np->e_name = savename(strrchr(name, '/') + 1);
 264         np->e_namlen = strlen(np->e_name);
 265         np->e_parent = ep;
 266         np->e_sibling = ep->e_entries;
 267         ep->e_entries = np;
 268         if (type & LINK) {
 269                 ep = lookupino(inum);
 270                 if (ep == NULL)
 271                         panic("link to non-existent name\n");
 272                 np->e_ino = inum;
 273                 np->e_links = ep->e_links;
 274                 ep->e_links = np;
 275         } else if (inum != 0) {
 276                 if (lookupino(inum) != NULL)
 277                         panic("duplicate entry\n");
 278                 addino(inum, np);
 279         }
 280         return (np);
 281 }
 282
 283 /*
 284  * delete an entry from the symbol table
 285  */
 286 void
 287 freeentry(struct entry *ep)
 288 {
 289         register struct entry *np;
 290         ino_t inum;
 291
 292         if (ep->e_flags != REMOVED)
 293                 badentry(ep, "not marked REMOVED");
 294         if (ep->e_type == NODE) {
 295                 if (ep->e_links != NULL)
 296                         badentry(ep, "freeing referenced directory");
 297                 if (ep->e_entries != NULL)
 298                         badentry(ep, "freeing non-empty directory");
 299         }
 300         if (ep->e_ino != 0) {
 301                 np = lookupino(ep->e_ino);
 302                 if (np == NULL)
 303                         badentry(ep, "lookupino failed");
 304                 if (np == ep) {
 305                         inum = ep->e_ino;
 306                         deleteino(inum);
 307                         if (ep->e_links != NULL)
 308                                 addino(inum, ep->e_links);
 309                 } else {
 310                         for (; np != NULL; np = np->e_links) {
 311                                 if (np->e_links == ep) {
 312                                         np->e_links = ep->e_links;
 313                                         break;
 314                                 }
 315                         }
 316                         if (np == NULL)
 317                                 badentry(ep, "link not found");
 318                 }
 319         }
 320         removeentry(ep);
 321         freename(ep->e_name);
 322         ep->e_next = freelist;
 323         freelist = ep;
 324 }
 325
 326 /*
 327  * Relocate an entry in the tree structure
 328  */
 329 void
 330 moveentry(struct entry *ep, char *newname)
 331 {
 332         struct entry *np;
 333         char *cp;
 334
 335         np = lookupparent(newname);
 336         if (np == NULL)
 337                 badentry(ep, "cannot move ROOT");
 338         if (np != ep->e_parent) {
 339                 removeentry(ep);
 340                 ep->e_parent = np;
 341                 ep->e_sibling = np->e_entries;
 342                 np->e_entries = ep;
 343         }
 344         cp = strrchr(newname, '/') + 1;
 345         freename(ep->e_name);
 346         ep->e_name = savename(cp);
 347         ep->e_namlen = strlen(cp);
 348         if (strcmp(gentempname(ep), ep->e_name) == 0)
 349                 ep->e_flags |= TMPNAME;
 350         else
 351                 ep->e_flags &= ~TMPNAME;
 352 }
 353
 354 /*
 355  * Remove an entry in the tree structure
 356  */
 357 static void
 358 removeentry(struct entry *ep)
 359 {
 360         register struct entry *np;
 361
 362         np = ep->e_parent;
 363         if (np->e_entries == ep) {
 364                 np->e_entries = ep->e_sibling;
 365         } else {
 366                 for (np = np->e_entries; np != NULL; np = np->e_sibling) {
 367                         if (np->e_sibling == ep) {
 368                                 np->e_sibling = ep->e_sibling;
 369                                 break;
 370                         }
 371                 }
 372                 if (np == NULL)
 373                         badentry(ep, "cannot find entry in parent list");
 374         }
 375 }
 376
 377 /*
 378  * Table of unused string entries, sorted by length.
 379  *
 380  * Entries are allocated in STRTBLINCR sized pieces so that names
 381  * of similar lengths can use the same entry. The value of STRTBLINCR
 382  * is chosen so that every entry has at least enough space to hold
 383  * a "struct strtbl" header. Thus every entry can be linked onto an
 384  * appropriate free list.
 385  *
 386  * NB. The macro "allocsize" below assumes that "struct strhdr"
 387  *     has a size that is a power of two.
 388  */
 389 struct strhdr {
 390         struct strhdr *next;
 391 };
 392
 393 #define STRTBLINCR      (sizeof(struct strhdr))
 394 #define allocsize(size) (((size) + 1 + STRTBLINCR - 1) & ~(STRTBLINCR - 1))
 395
 396 static struct strhdr strtblhdr[allocsize(MAXNAMLEN) / STRTBLINCR];
 397
 398 /*
 399  * Allocate space for a name. It first looks to see if it already
 400  * has an appropriate sized entry, and if not allocates a new one.
 401  */
 402 char *
 403 savename(char *name)
 404 {
 405         struct strhdr *np;
 406         long len;
 407         char *cp;
 408
 409         if (name == NULL)
 410                 panic("bad name\n");
 411         len = strlen(name);
 412         np = strtblhdr[len / STRTBLINCR].next;
 413         if (np != NULL) {
 414                 strtblhdr[len / STRTBLINCR].next = np->next;
 415                 cp = (char *)np;
 416         } else {
 417                 cp = malloc((unsigned)allocsize(len));
 418                 if (cp == NULL)
 419                         errx(1, "no space for string table");
 420         }
 421         (void) strcpy(cp, name);
 422         return (cp);
 423 }
 424
 425 /*
 426  * Free space for a name. The resulting entry is linked onto the
 427  * appropriate free list.
 428  */
 429 void
 430 freename(char *name)
 431 {
 432         struct strhdr *tp, *np;
 433
 434         tp = &strtblhdr[strlen(name) / STRTBLINCR];
 435         np = (struct strhdr *)name;
 436         np->next = tp->next;
 437         tp->next = np;
 438 }
 439
 440 /*
 441  * Useful quantities placed at the end of a dumped symbol table.
 442  */
 443 struct symtableheader {
 444         int32_t volno;
 445         int32_t stringsize;
 446         int32_t entrytblsize;
 447         time_t  dumptime;
 448         time_t  dumpdate;
 449         ino_t   maxino;
 450         int32_t ntrec;
 451 };
 452
 453 /*
 454  * dump a snapshot of the symbol table
 455  */
 456 void
 457 dumpsymtable(char *filename, long checkpt)
 458 {
 459         register struct entry *ep, *tep;
 460         register ino_t i;
 461         struct entry temp, *tentry;
 462         long mynum = 1, stroff = 0;
 463         FILE *fd;
 464         struct symtableheader hdr;
 465
 466         Vprintf(stdout, "Check pointing the restore\n");
 467         if (Nflag)
 468                 return;
 469         if ((fd = fopen(filename, "w")) == NULL) {
 470                 warn("fopen");
 471                 panic("cannot create save file %s for symbol table\n",
 472                         filename);
 473         }
 474         clearerr(fd);
 475         /*
 476          * Assign indices to each entry
 477          * Write out the string entries
 478          */
 479         for (i = WINO; i <= maxino; i++) {
 480                 for (ep = lookupino(i); ep != NULL; ep = ep->e_links) {
 481                         ep->e_index = mynum++;
 482                         (void) fwrite(ep->e_name, sizeof(char),
 483                                (int)allocsize(ep->e_namlen), fd);
 484                 }
 485         }
 486         /*
 487          * Convert pointers to indexes, and output
 488          */
 489         tep = &temp;
 490         stroff = 0;
 491         for (i = WINO; i <= maxino; i++) {
 492                 for (ep = lookupino(i); ep != NULL; ep = ep->e_links) {
 493                         memmove(tep, ep, sizeof(struct entry));
 494                         tep->e_name = (char *)stroff;
 495                         stroff += allocsize(ep->e_namlen);
 496                         tep->e_parent = (struct entry *)ep->e_parent->e_index;
 497                         if (ep->e_links != NULL)
 498                                 tep->e_links =
 499                                         (struct entry *)ep->e_links->e_index;
 500                         if (ep->e_sibling != NULL)
 501                                 tep->e_sibling =
 502                                         (struct entry *)ep->e_sibling->e_index;
 503                         if (ep->e_entries != NULL)
 504                                 tep->e_entries =
 505                                         (struct entry *)ep->e_entries->e_index;
 506                         if (ep->e_next != NULL)
 507                                 tep->e_next =
 508                                         (struct entry *)ep->e_next->e_index;
 509                         (void) fwrite((char *)tep, sizeof(struct entry), 1, fd);
 510                 }
 511         }
 512         /*
 513          * Convert entry pointers to indexes, and output
 514          */
 515         for (i = 0; i < entrytblsize; i++) {
 516                 if (entry[i] == NULL)
 517                         tentry = NULL;
 518                 else
 519                         tentry = (struct entry *)entry[i]->e_index;
 520                 (void) fwrite((char *)&tentry, sizeof(struct entry *), 1, fd);
 521         }
 522         hdr.volno = checkpt;
 523         hdr.maxino = maxino;
 524         hdr.entrytblsize = entrytblsize;
 525         hdr.stringsize = stroff;
 526         hdr.dumptime = dumptime;
 527         hdr.dumpdate = dumpdate;
 528         hdr.ntrec = ntrec;
 529         (void) fwrite((char *)&hdr, sizeof(struct symtableheader), 1, fd);
 530         if (ferror(fd)) {
 531                 warn("fwrite");
 532                 panic("output error to file %s writing symbol table\n",
 533                         filename);
 534         }
 535         (void) fclose(fd);
 536 }
 537
 538 /*
 539  * Initialize a symbol table from a file
 540  */
 541 void
 542 initsymtable(char *filename)
 543 {
 544         char *base;
 545         long tblsize;
 546         register struct entry *ep;
 547         struct entry *baseep, *lep;
 548         struct symtableheader hdr;
 549         struct stat stbuf;
 550         register long i;
 551         int fd;
 552
 553         Vprintf(stdout, "Initialize symbol table.\n");
 554         if (filename == NULL) {
 555                 entrytblsize = maxino / HASHFACTOR;
 556                 entry = (struct entry **)
 557                         calloc((unsigned)entrytblsize, sizeof(struct entry *));
 558                 if (entry == (struct entry **)NULL)
 559                         errx(1, "no memory for entry table");
 560                 ep = addentry(".", ROOTINO, NODE);
 561                 ep->e_flags |= NEW;
 562                 return;
 563         }
 564         if ((fd = open(filename, O_RDONLY, 0)) < 0) {
 565                 warn("open");
 566                 errx(1, "cannot open symbol table file %s", filename);
 567         }
 568         if (fstat(fd, &stbuf) < 0) {
 569                 warn("stat");
 570                 errx(1, "cannot stat symbol table file %s", filename);
 571         }
 572         tblsize = stbuf.st_size - sizeof(struct symtableheader);
 573         base = calloc(sizeof(char), (unsigned)tblsize);
 574         if (base == NULL)
 575                 errx(1, "cannot allocate space for symbol table");
 576         if (read(fd, base, (int)tblsize) < 0 ||
 577             read(fd, (char *)&hdr, sizeof(struct symtableheader)) < 0) {
 578                 warn("read");
 579                 errx(1, "cannot read symbol table file %s", filename);
 580         }
 581         switch (command) {
 582         case 'r':
 583                 /*
 584                  * For normal continuation, insure that we are using
 585                  * the next incremental tape
 586                  */
 587                 if (hdr.dumpdate != dumptime)
 588                         errx(1, "Incremental tape too %s",
 589                                 (hdr.dumpdate < dumptime) ? "low" : "high");
 590                 break;
 591         case 'R':
 592                 /*
 593                  * For restart, insure that we are using the same tape
 594                  */
 595                 curfile.action = SKIP;
 596                 dumptime = hdr.dumptime;
 597                 dumpdate = hdr.dumpdate;
 598                 if (!bflag)
 599                         newtapebuf(hdr.ntrec);
 600                 getvol(hdr.volno);
 601                 break;
 602         default:
 603                 panic("initsymtable called from command %c\n", command);
 604                 break;
 605         }
 606         maxino = hdr.maxino;
 607         entrytblsize = hdr.entrytblsize;
 608         entry = (struct entry **)
 609                 (base + tblsize - (entrytblsize * sizeof(struct entry *)));
 610         baseep = (struct entry *)(base + hdr.stringsize - sizeof(struct entry));
 611         lep = (struct entry *)entry;
 612         for (i = 0; i < entrytblsize; i++) {
 613                 if (entry[i] == NULL)
 614                         continue;
 615                 entry[i] = &baseep[(long)entry[i]];
 616         }
 617         for (ep = &baseep[1]; ep < lep; ep++) {
 618                 ep->e_name = base + (long)ep->e_name;
 619                 ep->e_parent = &baseep[(long)ep->e_parent];
 620                 if (ep->e_sibling != NULL)
 621                         ep->e_sibling = &baseep[(long)ep->e_sibling];
 622                 if (ep->e_links != NULL)
 623                         ep->e_links = &baseep[(long)ep->e_links];
 624                 if (ep->e_entries != NULL)
 625                         ep->e_entries = &baseep[(long)ep->e_entries];
 626                 if (ep->e_next != NULL)
 627                         ep->e_next = &baseep[(long)ep->e_next];
 628         }
 629 }