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@cybercable.fr>, 1999
   6  *
   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  * $Id: symtab.c,v 1.5 1999/10/11 13:31:13 stelian Exp $
  42  */
  43
  44 /*
  45  * These routines maintain the symbol table which tracks the state
  46  * of the file system being restored. They provide lookup by either
  47  * name or inode number. They also provide for creation, deletion,
  48  * and renaming of entries. Because of the dynamic nature of pathnames,
  49  * names should not be saved, but always constructed just before they
  50  * are needed, by calling "myname".
  51  */
  52
  53 #include <sys/param.h>
  54 #include <sys/stat.h>
  55
  56 #ifdef  __linux__
  57 #include <sys/time.h>
  58 #include <linux/ext2_fs.h>
  59 #include <bsdcompat.h>
  60 #else   /* __linux__ */
  61 #include <ufs/ufs/dinode.h>
  62 #endif  /* __linux__ */
  63
  64 #include <errno.h>
  65 #include <compaterr.h>
  66 #include <fcntl.h>
  67 #include <stdio.h>
  68 #include <stdlib.h>
  69 #include <string.h>
  70 #include <unistd.h>
  71
  72 #ifdef  __linux__
  73 #include <ext2fs/ext2fs.h>
  74 #endif
  75
  76 #include "restore.h"
  77 #include "extern.h"
  78
  79 /*
  80  * The following variables define the inode symbol table.
  81  * The primary hash table is dynamically allocated based on
  82  * the number of inodes in the file system (maxino), scaled by
  83  * HASHFACTOR. The variable "entry" points to the hash table;
  84  * the variable "entrytblsize" indicates its size (in entries).
  85  */
  86 #define HASHFACTOR 5
  87 static struct entry **entry;
  88 static long entrytblsize;
  89
  90 static void              addino __P((ino_t, struct entry *));
  91 static struct entry     *lookupparent __P((char *));
  92 static void              removeentry __P((struct entry *));
  93
  94 /*
  95  * Look up an entry by inode number
  96  */
  97 struct entry *
  98 lookupino(ino_t inum)
  99 {
 100         register struct entry *ep;
 101
 102         if (inum < WINO || inum >= maxino)
 103                 return (NULL);
 104         for (ep = entry[inum % entrytblsize]; ep != NULL; ep = ep->e_next)
 105                 if (ep->e_ino == inum)
 106                         return (ep);
 107         return (NULL);
 108 }
 109
 110 /*
 111  * Add an entry into the entry table
 112  */
 113 static void
 114 addino(ino_t inum, struct entry *np)
 115 {
 116         struct entry **epp;
 117
 118         if (inum < WINO || inum >= maxino)
 119                 panic("addino: out of range %d\n", inum);
 120         epp = &entry[inum % entrytblsize];
 121         np->e_ino = inum;
 122         np->e_next = *epp;
 123         *epp = np;
 124         if (dflag)
 125                 for (np = np->e_next; np != NULL; np = np->e_next)
 126                         if (np->e_ino == inum)
 127                                 badentry(np, "duplicate inum");
 128 }
 129
 130 /*
 131  * Delete an entry from the entry table
 132  */
 133 void
 134 deleteino(ino_t inum)
 135 {
 136         register struct entry *next;
 137         struct entry **prev;
 138
 139         if (inum < WINO || inum >= maxino)
 140                 panic("deleteino: out of range %d\n", inum);
 141         prev = &entry[inum % entrytblsize];
 142         for (next = *prev; next != NULL; next = next->e_next) {
 143                 if (next->e_ino == inum) {
 144                         next->e_ino = 0;
 145                         *prev = next->e_next;
 146                         return;
 147                 }
 148                 prev = &next->e_next;
 149         }
 150         panic("deleteino: %d not found\n", inum);
 151 }
 152
 153 /*
 154  * Look up an entry by name
 155  */
 156 struct entry *
 157 lookupname(char *name)
 158 {
 159         register struct entry *ep;
 160         register char *np, *cp;
 161         char buf[MAXPATHLEN];
 162
 163         cp = name;
 164         for (ep = lookupino(ROOTINO); ep != NULL; ep = ep->e_entries) {
 165                 for (np = buf; *cp != '/' && *cp != '\0' &&
 166                                 np < &buf[sizeof(buf)]; )
 167                         *np++ = *cp++;
 168                 if (np == &buf[sizeof(buf)])
 169                         break;
 170                 *np = '\0';
 171                 for ( ; ep != NULL; ep = ep->e_sibling)
 172                         if (strcmp(ep->e_name, buf) == 0)
 173                                 break;
 174                 if (ep == NULL)
 175                         break;
 176                 if (*cp++ == '\0')
 177                         return (ep);
 178         }
 179         return (NULL);
 180 }
 181
 182 /*
 183  * Look up the parent of a pathname
 184  */
 185 static struct entry *
 186 lookupparent(char *name)
 187 {
 188         struct entry *ep;
 189         char *tailindex;
 190
 191         tailindex = strrchr(name, '/');
 192         if (tailindex == NULL)
 193                 return (NULL);
 194         *tailindex = '\0';
 195         ep = lookupname(name);
 196         *tailindex = '/';
 197         if (ep == NULL)
 198                 return (NULL);
 199         if (ep->e_type != NODE)
 200                 panic("%s is not a directory\n", name);
 201         return (ep);
 202 }
 203
 204 /*
 205  * Determine the current pathname of a node or leaf
 206  */
 207 char *
 208 myname(struct entry *ep)
 209 {
 210         register char *cp;
 211         static char namebuf[MAXPATHLEN];
 212
 213         for (cp = &namebuf[MAXPATHLEN - 2]; cp > &namebuf[ep->e_namlen]; ) {
 214                 cp -= ep->e_namlen;
 215                 memmove(cp, ep->e_name, (size_t)ep->e_namlen);
 216                 if (ep == lookupino(ROOTINO))
 217                         return (cp);
 218                 *(--cp) = '/';
 219                 ep = ep->e_parent;
 220         }
 221         panic("%s: pathname too long\n", cp);
 222         return(cp);
 223 }
 224
 225 /*
 226  * Unused symbol table entries are linked together on a free list
 227  * headed by the following pointer.
 228  */
 229 static struct entry *freelist = NULL;
 230
 231 /*
 232  * add an entry to the symbol table
 233  */
 234 struct entry *
 235 addentry(char *name, ino_t inum, int type)
 236 {
 237         register struct entry *np, *ep;
 238
 239         if (freelist != NULL) {
 240                 np = freelist;
 241                 freelist = np->e_next;
 242                 memset(np, 0, sizeof(struct entry));
 243         } else {
 244                 np = (struct entry *)calloc(1, sizeof(struct entry));
 245                 if (np == NULL)
 246                         panic("no memory to extend symbol table\n");
 247         }
 248         np->e_type = type & ~LINK;
 249         ep = lookupparent(name);
 250         if (ep == NULL) {
 251                 if (inum != ROOTINO || lookupino(ROOTINO) != NULL)
 252                         panic("bad name to addentry %s\n", name);
 253                 np->e_name = savename(name);
 254                 np->e_namlen = strlen(name);
 255                 np->e_parent = np;
 256                 addino(ROOTINO, np);
 257                 return (np);
 258         }
 259         np->e_name = savename(strrchr(name, '/') + 1);
 260         np->e_namlen = strlen(np->e_name);
 261         np->e_parent = ep;
 262         np->e_sibling = ep->e_entries;
 263         ep->e_entries = np;
 264         if (type & LINK) {
 265                 ep = lookupino(inum);
 266                 if (ep == NULL)
 267                         panic("link to non-existent name\n");
 268                 np->e_ino = inum;
 269                 np->e_links = ep->e_links;
 270                 ep->e_links = np;
 271         } else if (inum != 0) {
 272                 if (lookupino(inum) != NULL)
 273                         panic("duplicate entry\n");
 274                 addino(inum, np);
 275         }
 276         return (np);
 277 }
 278
 279 /*
 280  * delete an entry from the symbol table
 281  */
 282 void
 283 freeentry(struct entry *ep)
 284 {
 285         register struct entry *np;
 286         ino_t inum;
 287
 288         if (ep->e_flags != REMOVED)
 289                 badentry(ep, "not marked REMOVED");
 290         if (ep->e_type == NODE) {
 291                 if (ep->e_links != NULL)
 292                         badentry(ep, "freeing referenced directory");
 293                 if (ep->e_entries != NULL)
 294                         badentry(ep, "freeing non-empty directory");
 295         }
 296         if (ep->e_ino != 0) {
 297                 np = lookupino(ep->e_ino);
 298                 if (np == NULL)
 299                         badentry(ep, "lookupino failed");
 300                 if (np == ep) {
 301                         inum = ep->e_ino;
 302                         deleteino(inum);
 303                         if (ep->e_links != NULL)
 304                                 addino(inum, ep->e_links);
 305                 } else {
 306                         for (; np != NULL; np = np->e_links) {
 307                                 if (np->e_links == ep) {
 308                                         np->e_links = ep->e_links;
 309                                         break;
 310                                 }
 311                         }
 312                         if (np == NULL)
 313                                 badentry(ep, "link not found");
 314                 }
 315         }
 316         removeentry(ep);
 317         freename(ep->e_name);
 318         ep->e_next = freelist;
 319         freelist = ep;
 320 }
 321
 322 /*
 323  * Relocate an entry in the tree structure
 324  */
 325 void
 326 moveentry(struct entry *ep, char *newname)
 327 {
 328         struct entry *np;
 329         char *cp;
 330
 331         np = lookupparent(newname);
 332         if (np == NULL)
 333                 badentry(ep, "cannot move ROOT");
 334         if (np != ep->e_parent) {
 335                 removeentry(ep);
 336                 ep->e_parent = np;
 337                 ep->e_sibling = np->e_entries;
 338                 np->e_entries = ep;
 339         }
 340         cp = strrchr(newname, '/') + 1;
 341         freename(ep->e_name);
 342         ep->e_name = savename(cp);
 343         ep->e_namlen = strlen(cp);
 344         if (strcmp(gentempname(ep), ep->e_name) == 0)
 345                 ep->e_flags |= TMPNAME;
 346         else
 347                 ep->e_flags &= ~TMPNAME;
 348 }
 349
 350 /*
 351  * Remove an entry in the tree structure
 352  */
 353 static void
 354 removeentry(struct entry *ep)
 355 {
 356         register struct entry *np;
 357
 358         np = ep->e_parent;
 359         if (np->e_entries == ep) {
 360                 np->e_entries = ep->e_sibling;
 361         } else {
 362                 for (np = np->e_entries; np != NULL; np = np->e_sibling) {
 363                         if (np->e_sibling == ep) {
 364                                 np->e_sibling = ep->e_sibling;
 365                                 break;
 366                         }
 367                 }
 368                 if (np == NULL)
 369                         badentry(ep, "cannot find entry in parent list");
 370         }
 371 }
 372
 373 /*
 374  * Table of unused string entries, sorted by length.
 375  *
 376  * Entries are allocated in STRTBLINCR sized pieces so that names
 377  * of similar lengths can use the same entry. The value of STRTBLINCR
 378  * is chosen so that every entry has at least enough space to hold
 379  * a "struct strtbl" header. Thus every entry can be linked onto an
 380  * appropriate free list.
 381  *
 382  * NB. The macro "allocsize" below assumes that "struct strhdr"
 383  *     has a size that is a power of two.
 384  */
 385 struct strhdr {
 386         struct strhdr *next;
 387 };
 388
 389 #define STRTBLINCR      (sizeof(struct strhdr))
 390 #define allocsize(size) (((size) + 1 + STRTBLINCR - 1) & ~(STRTBLINCR - 1))
 391
 392 static struct strhdr strtblhdr[allocsize(NAME_MAX) / STRTBLINCR];
 393
 394 /*
 395  * Allocate space for a name. It first looks to see if it already
 396  * has an appropriate sized entry, and if not allocates a new one.
 397  */
 398 char *
 399 savename(char *name)
 400 {
 401         struct strhdr *np;
 402         long len;
 403         char *cp;
 404
 405         if (name == NULL)
 406                 panic("bad name\n");
 407         len = strlen(name);
 408         np = strtblhdr[len / STRTBLINCR].next;
 409         if (np != NULL) {
 410                 strtblhdr[len / STRTBLINCR].next = np->next;
 411                 cp = (char *)np;
 412         } else {
 413                 cp = malloc((unsigned)allocsize(len));
 414                 if (cp == NULL)
 415                         panic("no space for string table\n");
 416         }
 417         (void) strcpy(cp, name);
 418         return (cp);
 419 }
 420
 421 /*
 422  * Free space for a name. The resulting entry is linked onto the
 423  * appropriate free list.
 424  */
 425 void
 426 freename(char *name)
 427 {
 428         struct strhdr *tp, *np;
 429
 430         tp = &strtblhdr[strlen(name) / STRTBLINCR];
 431         np = (struct strhdr *)name;
 432         np->next = tp->next;
 433         tp->next = np;
 434 }
 435
 436 /*
 437  * Useful quantities placed at the end of a dumped symbol table.
 438  */
 439 struct symtableheader {
 440         int32_t volno;
 441         int32_t stringsize;
 442         int32_t entrytblsize;
 443         time_t  dumptime;
 444         time_t  dumpdate;
 445         ino_t   maxino;
 446         int32_t ntrec;
 447 };
 448
 449 /*
 450  * dump a snapshot of the symbol table
 451  */
 452 void
 453 dumpsymtable(char *filename, long checkpt)
 454 {
 455         register struct entry *ep, *tep;
 456         register ino_t i;
 457         struct entry temp, *tentry;
 458         long mynum = 1, stroff = 0;
 459         FILE *fd;
 460         struct symtableheader hdr;
 461
 462         Vprintf(stdout, "Check pointing the restore\n");
 463         if (Nflag)
 464                 return;
 465         if ((fd = fopen(filename, "w")) == NULL) {
 466                 warn("fopen");
 467                 panic("cannot create save file %s for symbol table\n",
 468                         filename);
 469         }
 470         clearerr(fd);
 471         /*
 472          * Assign indices to each entry
 473          * Write out the string entries
 474          */
 475         for (i = WINO; i <= maxino; i++) {
 476                 for (ep = lookupino(i); ep != NULL; ep = ep->e_links) {
 477                         ep->e_index = mynum++;
 478                         (void) fwrite(ep->e_name, sizeof(char),
 479                                (int)allocsize(ep->e_namlen), fd);
 480                 }
 481         }
 482         /*
 483          * Convert pointers to indexes, and output
 484          */
 485         tep = &temp;
 486         stroff = 0;
 487         for (i = WINO; i <= maxino; i++) {
 488                 for (ep = lookupino(i); ep != NULL; ep = ep->e_links) {
 489                         memmove(tep, ep, sizeof(struct entry));
 490                         tep->e_name = (char *)stroff;
 491                         stroff += allocsize(ep->e_namlen);
 492                         tep->e_parent = (struct entry *)ep->e_parent->e_index;
 493                         if (ep->e_links != NULL)
 494                                 tep->e_links =
 495                                         (struct entry *)ep->e_links->e_index;
 496                         if (ep->e_sibling != NULL)
 497                                 tep->e_sibling =
 498                                         (struct entry *)ep->e_sibling->e_index;
 499                         if (ep->e_entries != NULL)
 500                                 tep->e_entries =
 501                                         (struct entry *)ep->e_entries->e_index;
 502                         if (ep->e_next != NULL)
 503                                 tep->e_next =
 504                                         (struct entry *)ep->e_next->e_index;
 505                         (void) fwrite((char *)tep, sizeof(struct entry), 1, fd);
 506                 }
 507         }
 508         /*
 509          * Convert entry pointers to indexes, and output
 510          */
 511         for (i = 0; i < entrytblsize; i++) {
 512                 if (entry[i] == NULL)
 513                         tentry = NULL;
 514                 else
 515                         tentry = (struct entry *)entry[i]->e_index;
 516                 (void) fwrite((char *)&tentry, sizeof(struct entry *), 1, fd);
 517         }
 518         hdr.volno = checkpt;
 519         hdr.maxino = maxino;
 520         hdr.entrytblsize = entrytblsize;
 521         hdr.stringsize = stroff;
 522         hdr.dumptime = dumptime;
 523         hdr.dumpdate = dumpdate;
 524         hdr.ntrec = ntrec;
 525         (void) fwrite((char *)&hdr, sizeof(struct symtableheader), 1, fd);
 526         if (ferror(fd)) {
 527                 warn("fwrite");
 528                 panic("output error to file %s writing symbol table\n",
 529                         filename);
 530         }
 531         (void) fclose(fd);
 532 }
 533
 534 /*
 535  * Initialize a symbol table from a file
 536  */
 537 void
 538 initsymtable(char *filename)
 539 {
 540         char *base;
 541         long tblsize;
 542         register struct entry *ep;
 543         struct entry *baseep, *lep;
 544         struct symtableheader hdr;
 545         struct stat stbuf;
 546         register long i;
 547         int fd;
 548
 549         Vprintf(stdout, "Initialize symbol table.\n");
 550         if (filename == NULL) {
 551                 entrytblsize = maxino / HASHFACTOR;
 552                 entry = (struct entry **)
 553                         calloc((unsigned)entrytblsize, sizeof(struct entry *));
 554                 if (entry == (struct entry **)NULL)
 555                         panic("no memory for entry table\n");
 556                 ep = addentry(".", ROOTINO, NODE);
 557                 ep->e_flags |= NEW;
 558                 return;
 559         }
 560         if ((fd = open(filename, O_RDONLY, 0)) < 0) {
 561                 warn("open");
 562                 panic("cannot open symbol table file %s\n", filename);
 563         }
 564         if (fstat(fd, &stbuf) < 0) {
 565                 warn("stat");
 566                 panic("cannot stat symbol table file %s\n", filename);
 567         }
 568         tblsize = stbuf.st_size - sizeof(struct symtableheader);
 569         base = calloc(sizeof(char), (unsigned)tblsize);
 570         if (base == NULL)
 571                 panic("cannot allocate space for symbol table\n");
 572         if (read(fd, base, (int)tblsize) < 0 ||
 573             read(fd, (char *)&hdr, sizeof(struct symtableheader)) < 0) {
 574                 warn("read");
 575                 panic("cannot read symbol table file %s\n", filename);
 576         }
 577         switch (command) {
 578         case 'r':
 579                 /*
 580                  * For normal continuation, insure that we are using
 581                  * the next incremental tape
 582                  */
 583                 if (hdr.dumpdate != dumptime)
 584                         errx(1, "Incremental tape too %s",
 585                                 (hdr.dumpdate < dumptime) ? "low" : "high");
 586                 break;
 587         case 'R':
 588                 /*
 589                  * For restart, insure that we are using the same tape
 590                  */
 591                 curfile.action = SKIP;
 592                 dumptime = hdr.dumptime;
 593                 dumpdate = hdr.dumpdate;
 594                 if (!bflag)
 595                         newtapebuf(hdr.ntrec);
 596                 getvol(hdr.volno);
 597                 break;
 598         default:
 599                 panic("initsymtable called from command %c\n", command);
 600                 break;
 601         }
 602         maxino = hdr.maxino;
 603         entrytblsize = hdr.entrytblsize;
 604         entry = (struct entry **)
 605                 (base + tblsize - (entrytblsize * sizeof(struct entry *)));
 606         baseep = (struct entry *)(base + hdr.stringsize - sizeof(struct entry));
 607         lep = (struct entry *)entry;
 608         for (i = 0; i < entrytblsize; i++) {
 609                 if (entry[i] == NULL)
 610                         continue;
 611                 entry[i] = &baseep[(long)entry[i]];
 612         }
 613         for (ep = &baseep[1]; ep < lep; ep++) {
 614                 ep->e_name = base + (long)ep->e_name;
 615                 ep->e_parent = &baseep[(long)ep->e_parent];
 616                 if (ep->e_sibling != NULL)
 617                         ep->e_sibling = &baseep[(long)ep->e_sibling];
 618                 if (ep->e_links != NULL)
 619                         ep->e_links = &baseep[(long)ep->e_links];
 620                 if (ep->e_entries != NULL)
 621                         ep->e_entries = &baseep[(long)ep->e_entries];
 622                 if (ep->e_next != NULL)
 623                         ep->e_next = &baseep[(long)ep->e_next];
 624         }
 625 }