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
  42 #ifndef lint
  43 #if 0
  44 static char sccsid[] = "@(#)symtab.c    8.3 (Berkeley) 4/28/95";
  45 #endif
  46 static const char rcsid[] =
  47         "$Id: symtab.c,v 1.3 1999/10/11 12:59:20 stelian Exp $";
  48 #endif /* not lint */
  49
  50 /*
  51  * These routines maintain the symbol table which tracks the state
  52  * of the file system being restored. They provide lookup by either
  53  * name or inode number. They also provide for creation, deletion,
  54  * and renaming of entries. Because of the dynamic nature of pathnames,
  55  * names should not be saved, but always constructed just before they
  56  * are needed, by calling "myname".
  57  */
  58
  59 #include <sys/param.h>
  60 #include <sys/stat.h>
  61
  62 #ifdef  __linux__
  63 #include <sys/time.h>
  64 #include <linux/ext2_fs.h>
  65 #include <bsdcompat.h>
  66 #else   /* __linux__ */
  67 #include <ufs/ufs/dinode.h>
  68 #endif  /* __linux__ */
  69
  70 #include <errno.h>
  71 #include <compaterr.h>
  72 #include <fcntl.h>
  73 #include <stdio.h>
  74 #include <stdlib.h>
  75 #include <string.h>
  76 #include <unistd.h>
  77
  78 #ifdef  __linux__
  79 #include <ext2fs/ext2fs.h>
  80 #endif
  81
  82 #include "restore.h"
  83 #include "extern.h"
  84
  85 /*
  86  * The following variables define the inode symbol table.
  87  * The primary hash table is dynamically allocated based on
  88  * the number of inodes in the file system (maxino), scaled by
  89  * HASHFACTOR. The variable "entry" points to the hash table;
  90  * the variable "entrytblsize" indicates its size (in entries).
  91  */
  92 #define HASHFACTOR 5
  93 static struct entry **entry;
  94 static long entrytblsize;
  95
  96 static void              addino __P((ino_t, struct entry *));
  97 static struct entry     *lookupparent __P((char *));
  98 static void              removeentry __P((struct entry *));
  99
 100 /*
 101  * Look up an entry by inode number
 102  */
 103 struct entry *
 104 lookupino(ino_t inum)
 105 {
 106         register struct entry *ep;
 107
 108         if (inum < WINO || inum >= maxino)
 109                 return (NULL);
 110         for (ep = entry[inum % entrytblsize]; ep != NULL; ep = ep->e_next)
 111                 if (ep->e_ino == inum)
 112                         return (ep);
 113         return (NULL);
 114 }
 115
 116 /*
 117  * Add an entry into the entry table
 118  */
 119 static void
 120 addino(ino_t inum, struct entry *np)
 121 {
 122         struct entry **epp;
 123
 124         if (inum < WINO || inum >= maxino)
 125                 panic("addino: out of range %d\n", inum);
 126         epp = &entry[inum % entrytblsize];
 127         np->e_ino = inum;
 128         np->e_next = *epp;
 129         *epp = np;
 130         if (dflag)
 131                 for (np = np->e_next; np != NULL; np = np->e_next)
 132                         if (np->e_ino == inum)
 133                                 badentry(np, "duplicate inum");
 134 }
 135
 136 /*
 137  * Delete an entry from the entry table
 138  */
 139 void
 140 deleteino(ino_t inum)
 141 {
 142         register struct entry *next;
 143         struct entry **prev;
 144
 145         if (inum < WINO || inum >= maxino)
 146                 panic("deleteino: out of range %d\n", inum);
 147         prev = &entry[inum % entrytblsize];
 148         for (next = *prev; next != NULL; next = next->e_next) {
 149                 if (next->e_ino == inum) {
 150                         next->e_ino = 0;
 151                         *prev = next->e_next;
 152                         return;
 153                 }
 154                 prev = &next->e_next;
 155         }
 156         panic("deleteino: %d not found\n", inum);
 157 }
 158
 159 /*
 160  * Look up an entry by name
 161  */
 162 struct entry *
 163 lookupname(char *name)
 164 {
 165         register struct entry *ep;
 166         register char *np, *cp;
 167         char buf[MAXPATHLEN];
 168
 169         cp = name;
 170         for (ep = lookupino(ROOTINO); ep != NULL; ep = ep->e_entries) {
 171                 for (np = buf; *cp != '/' && *cp != '\0' &&
 172                                 np < &buf[sizeof(buf)]; )
 173                         *np++ = *cp++;
 174                 if (np == &buf[sizeof(buf)])
 175                         break;
 176                 *np = '\0';
 177                 for ( ; ep != NULL; ep = ep->e_sibling)
 178                         if (strcmp(ep->e_name, buf) == 0)
 179                                 break;
 180                 if (ep == NULL)
 181                         break;
 182                 if (*cp++ == '\0')
 183                         return (ep);
 184         }
 185         return (NULL);
 186 }
 187
 188 /*
 189  * Look up the parent of a pathname
 190  */
 191 static struct entry *
 192 lookupparent(char *name)
 193 {
 194         struct entry *ep;
 195         char *tailindex;
 196
 197         tailindex = strrchr(name, '/');
 198         if (tailindex == NULL)
 199                 return (NULL);
 200         *tailindex = '\0';
 201         ep = lookupname(name);
 202         *tailindex = '/';
 203         if (ep == NULL)
 204                 return (NULL);
 205         if (ep->e_type != NODE)
 206                 panic("%s is not a directory\n", name);
 207         return (ep);
 208 }
 209
 210 /*
 211  * Determine the current pathname of a node or leaf
 212  */
 213 char *
 214 myname(struct entry *ep)
 215 {
 216         register char *cp;
 217         static char namebuf[MAXPATHLEN];
 218
 219         for (cp = &namebuf[MAXPATHLEN - 2]; cp > &namebuf[ep->e_namlen]; ) {
 220                 cp -= ep->e_namlen;
 221                 memmove(cp, ep->e_name, (size_t)ep->e_namlen);
 222                 if (ep == lookupino(ROOTINO))
 223                         return (cp);
 224                 *(--cp) = '/';
 225                 ep = ep->e_parent;
 226         }
 227         panic("%s: pathname too long\n", cp);
 228         return(cp);
 229 }
 230
 231 /*
 232  * Unused symbol table entries are linked together on a free list
 233  * headed by the following pointer.
 234  */
 235 static struct entry *freelist = NULL;
 236
 237 /*
 238  * add an entry to the symbol table
 239  */
 240 struct entry *
 241 addentry(char *name, ino_t inum, int type)
 242 {
 243         register struct entry *np, *ep;
 244
 245         if (freelist != NULL) {
 246                 np = freelist;
 247                 freelist = np->e_next;
 248                 memset(np, 0, sizeof(struct entry));
 249         } else {
 250                 np = (struct entry *)calloc(1, sizeof(struct entry));
 251                 if (np == NULL)
 252                         panic("no memory to extend symbol table\n");
 253         }
 254         np->e_type = type & ~LINK;
 255         ep = lookupparent(name);
 256         if (ep == NULL) {
 257                 if (inum != ROOTINO || lookupino(ROOTINO) != NULL)
 258                         panic("bad name to addentry %s\n", name);
 259                 np->e_name = savename(name);
 260                 np->e_namlen = strlen(name);
 261                 np->e_parent = np;
 262                 addino(ROOTINO, np);
 263                 return (np);
 264         }
 265         np->e_name = savename(strrchr(name, '/') + 1);
 266         np->e_namlen = strlen(np->e_name);
 267         np->e_parent = ep;
 268         np->e_sibling = ep->e_entries;
 269         ep->e_entries = np;
 270         if (type & LINK) {
 271                 ep = lookupino(inum);
 272                 if (ep == NULL)
 273                         panic("link to non-existent name\n");
 274                 np->e_ino = inum;
 275                 np->e_links = ep->e_links;
 276                 ep->e_links = np;
 277         } else if (inum != 0) {
 278                 if (lookupino(inum) != NULL)
 279                         panic("duplicate entry\n");
 280                 addino(inum, np);
 281         }
 282         return (np);
 283 }
 284
 285 /*
 286  * delete an entry from the symbol table
 287  */
 288 void
 289 freeentry(struct entry *ep)
 290 {
 291         register struct entry *np;
 292         ino_t inum;
 293
 294         if (ep->e_flags != REMOVED)
 295                 badentry(ep, "not marked REMOVED");
 296         if (ep->e_type == NODE) {
 297                 if (ep->e_links != NULL)
 298                         badentry(ep, "freeing referenced directory");
 299                 if (ep->e_entries != NULL)
 300                         badentry(ep, "freeing non-empty directory");
 301         }
 302         if (ep->e_ino != 0) {
 303                 np = lookupino(ep->e_ino);
 304                 if (np == NULL)
 305                         badentry(ep, "lookupino failed");
 306                 if (np == ep) {
 307                         inum = ep->e_ino;
 308                         deleteino(inum);
 309                         if (ep->e_links != NULL)
 310                                 addino(inum, ep->e_links);
 311                 } else {
 312                         for (; np != NULL; np = np->e_links) {
 313                                 if (np->e_links == ep) {
 314                                         np->e_links = ep->e_links;
 315                                         break;
 316                                 }
 317                         }
 318                         if (np == NULL)
 319                                 badentry(ep, "link not found");
 320                 }
 321         }
 322         removeentry(ep);
 323         freename(ep->e_name);
 324         ep->e_next = freelist;
 325         freelist = ep;
 326 }
 327
 328 /*
 329  * Relocate an entry in the tree structure
 330  */
 331 void
 332 moveentry(struct entry *ep, char *newname)
 333 {
 334         struct entry *np;
 335         char *cp;
 336
 337         np = lookupparent(newname);
 338         if (np == NULL)
 339                 badentry(ep, "cannot move ROOT");
 340         if (np != ep->e_parent) {
 341                 removeentry(ep);
 342                 ep->e_parent = np;
 343                 ep->e_sibling = np->e_entries;
 344                 np->e_entries = ep;
 345         }
 346         cp = strrchr(newname, '/') + 1;
 347         freename(ep->e_name);
 348         ep->e_name = savename(cp);
 349         ep->e_namlen = strlen(cp);
 350         if (strcmp(gentempname(ep), ep->e_name) == 0)
 351                 ep->e_flags |= TMPNAME;
 352         else
 353                 ep->e_flags &= ~TMPNAME;
 354 }
 355
 356 /*
 357  * Remove an entry in the tree structure
 358  */
 359 static void
 360 removeentry(struct entry *ep)
 361 {
 362         register struct entry *np;
 363
 364         np = ep->e_parent;
 365         if (np->e_entries == ep) {
 366                 np->e_entries = ep->e_sibling;
 367         } else {
 368                 for (np = np->e_entries; np != NULL; np = np->e_sibling) {
 369                         if (np->e_sibling == ep) {
 370                                 np->e_sibling = ep->e_sibling;
 371                                 break;
 372                         }
 373                 }
 374                 if (np == NULL)
 375                         badentry(ep, "cannot find entry in parent list");
 376         }
 377 }
 378
 379 /*
 380  * Table of unused string entries, sorted by length.
 381  *
 382  * Entries are allocated in STRTBLINCR sized pieces so that names
 383  * of similar lengths can use the same entry. The value of STRTBLINCR
 384  * is chosen so that every entry has at least enough space to hold
 385  * a "struct strtbl" header. Thus every entry can be linked onto an
 386  * appropriate free list.
 387  *
 388  * NB. The macro "allocsize" below assumes that "struct strhdr"
 389  *     has a size that is a power of two.
 390  */
 391 struct strhdr {
 392         struct strhdr *next;
 393 };
 394
 395 #define STRTBLINCR      (sizeof(struct strhdr))
 396 #define allocsize(size) (((size) + 1 + STRTBLINCR - 1) & ~(STRTBLINCR - 1))
 397
 398 static struct strhdr strtblhdr[allocsize(NAME_MAX) / STRTBLINCR];
 399
 400 /*
 401  * Allocate space for a name. It first looks to see if it already
 402  * has an appropriate sized entry, and if not allocates a new one.
 403  */
 404 char *
 405 savename(char *name)
 406 {
 407         struct strhdr *np;
 408         long len;
 409         char *cp;
 410
 411         if (name == NULL)
 412                 panic("bad name\n");
 413         len = strlen(name);
 414         np = strtblhdr[len / STRTBLINCR].next;
 415         if (np != NULL) {
 416                 strtblhdr[len / STRTBLINCR].next = np->next;
 417                 cp = (char *)np;
 418         } else {
 419                 cp = malloc((unsigned)allocsize(len));
 420                 if (cp == NULL)
 421                         panic("no space for string table\n");
 422         }
 423         (void) strcpy(cp, name);
 424         return (cp);
 425 }
 426
 427 /*
 428  * Free space for a name. The resulting entry is linked onto the
 429  * appropriate free list.
 430  */
 431 void
 432 freename(char *name)
 433 {
 434         struct strhdr *tp, *np;
 435
 436         tp = &strtblhdr[strlen(name) / STRTBLINCR];
 437         np = (struct strhdr *)name;
 438         np->next = tp->next;
 439         tp->next = np;
 440 }
 441
 442 /*
 443  * Useful quantities placed at the end of a dumped symbol table.
 444  */
 445 struct symtableheader {
 446         int32_t volno;
 447         int32_t stringsize;
 448         int32_t entrytblsize;
 449         time_t  dumptime;
 450         time_t  dumpdate;
 451         ino_t   maxino;
 452         int32_t ntrec;
 453 };
 454
 455 /*
 456  * dump a snapshot of the symbol table
 457  */
 458 void
 459 dumpsymtable(char *filename, long checkpt)
 460 {
 461         register struct entry *ep, *tep;
 462         register ino_t i;
 463         struct entry temp, *tentry;
 464         long mynum = 1, stroff = 0;
 465         FILE *fd;
 466         struct symtableheader hdr;
 467
 468         Vprintf(stdout, "Check pointing the restore\n");
 469         if (Nflag)
 470                 return;
 471         if ((fd = fopen(filename, "w")) == NULL) {
 472                 warn("fopen");
 473                 panic("cannot create save file %s for symbol table\n",
 474                         filename);
 475         }
 476         clearerr(fd);
 477         /*
 478          * Assign indices to each entry
 479          * Write out the string entries
 480          */
 481         for (i = WINO; i <= maxino; i++) {
 482                 for (ep = lookupino(i); ep != NULL; ep = ep->e_links) {
 483                         ep->e_index = mynum++;
 484                         (void) fwrite(ep->e_name, sizeof(char),
 485                                (int)allocsize(ep->e_namlen), fd);
 486                 }
 487         }
 488         /*
 489          * Convert pointers to indexes, and output
 490          */
 491         tep = &temp;
 492         stroff = 0;
 493         for (i = WINO; i <= maxino; i++) {
 494                 for (ep = lookupino(i); ep != NULL; ep = ep->e_links) {
 495                         memmove(tep, ep, sizeof(struct entry));
 496                         tep->e_name = (char *)stroff;
 497                         stroff += allocsize(ep->e_namlen);
 498                         tep->e_parent = (struct entry *)ep->e_parent->e_index;
 499                         if (ep->e_links != NULL)
 500                                 tep->e_links =
 501                                         (struct entry *)ep->e_links->e_index;
 502                         if (ep->e_sibling != NULL)
 503                                 tep->e_sibling =
 504                                         (struct entry *)ep->e_sibling->e_index;
 505                         if (ep->e_entries != NULL)
 506                                 tep->e_entries =
 507                                         (struct entry *)ep->e_entries->e_index;
 508                         if (ep->e_next != NULL)
 509                                 tep->e_next =
 510                                         (struct entry *)ep->e_next->e_index;
 511                         (void) fwrite((char *)tep, sizeof(struct entry), 1, fd);
 512                 }
 513         }
 514         /*
 515          * Convert entry pointers to indexes, and output
 516          */
 517         for (i = 0; i < entrytblsize; i++) {
 518                 if (entry[i] == NULL)
 519                         tentry = NULL;
 520                 else
 521                         tentry = (struct entry *)entry[i]->e_index;
 522                 (void) fwrite((char *)&tentry, sizeof(struct entry *), 1, fd);
 523         }
 524         hdr.volno = checkpt;
 525         hdr.maxino = maxino;
 526         hdr.entrytblsize = entrytblsize;
 527         hdr.stringsize = stroff;
 528         hdr.dumptime = dumptime;
 529         hdr.dumpdate = dumpdate;
 530         hdr.ntrec = ntrec;
 531         (void) fwrite((char *)&hdr, sizeof(struct symtableheader), 1, fd);
 532         if (ferror(fd)) {
 533                 warn("fwrite");
 534                 panic("output error to file %s writing symbol table\n",
 535                         filename);
 536         }
 537         (void) fclose(fd);
 538 }
 539
 540 /*
 541  * Initialize a symbol table from a file
 542  */
 543 void
 544 initsymtable(char *filename)
 545 {
 546         char *base;
 547         long tblsize;
 548         register struct entry *ep;
 549         struct entry *baseep, *lep;
 550         struct symtableheader hdr;
 551         struct stat stbuf;
 552         register long i;
 553         int fd;
 554
 555         Vprintf(stdout, "Initialize symbol table.\n");
 556         if (filename == NULL) {
 557                 entrytblsize = maxino / HASHFACTOR;
 558                 entry = (struct entry **)
 559                         calloc((unsigned)entrytblsize, sizeof(struct entry *));
 560                 if (entry == (struct entry **)NULL)
 561                         panic("no memory for entry table\n");
 562                 ep = addentry(".", ROOTINO, NODE);
 563                 ep->e_flags |= NEW;
 564                 return;
 565         }
 566         if ((fd = open(filename, O_RDONLY, 0)) < 0) {
 567                 warn("open");
 568                 panic("cannot open symbol table file %s\n", filename);
 569         }
 570         if (fstat(fd, &stbuf) < 0) {
 571                 warn("stat");
 572                 panic("cannot stat symbol table file %s\n", filename);
 573         }
 574         tblsize = stbuf.st_size - sizeof(struct symtableheader);
 575         base = calloc(sizeof(char), (unsigned)tblsize);
 576         if (base == NULL)
 577                 panic("cannot allocate space for symbol table\n");
 578         if (read(fd, base, (int)tblsize) < 0 ||
 579             read(fd, (char *)&hdr, sizeof(struct symtableheader)) < 0) {
 580                 warn("read");
 581                 panic("cannot read symbol table file %s\n", filename);
 582         }
 583         switch (command) {
 584         case 'r':
 585                 /*
 586                  * For normal continuation, insure that we are using
 587                  * the next incremental tape
 588                  */
 589                 if (hdr.dumpdate != dumptime)
 590                         errx(1, "Incremental tape too %s",
 591                                 (hdr.dumpdate < dumptime) ? "low" : "high");
 592                 break;
 593         case 'R':
 594                 /*
 595                  * For restart, insure that we are using the same tape
 596                  */
 597                 curfile.action = SKIP;
 598                 dumptime = hdr.dumptime;
 599                 dumpdate = hdr.dumpdate;
 600                 if (!bflag)
 601                         newtapebuf(hdr.ntrec);
 602                 getvol(hdr.volno);
 603                 break;
 604         default:
 605                 panic("initsymtable called from command %c\n", command);
 606                 break;
 607         }
 608         maxino = hdr.maxino;
 609         entrytblsize = hdr.entrytblsize;
 610         entry = (struct entry **)
 611                 (base + tblsize - (entrytblsize * sizeof(struct entry *)));
 612         baseep = (struct entry *)(base + hdr.stringsize - sizeof(struct entry));
 613         lep = (struct entry *)entry;
 614         for (i = 0; i < entrytblsize; i++) {
 615                 if (entry[i] == NULL)
 616                         continue;
 617                 entry[i] = &baseep[(long)entry[i]];
 618         }
 619         for (ep = &baseep[1]; ep < lep; ep++) {
 620                 ep->e_name = base + (long)ep->e_name;
 621                 ep->e_parent = &baseep[(long)ep->e_parent];
 622                 if (ep->e_sibling != NULL)
 623                         ep->e_sibling = &baseep[(long)ep->e_sibling];
 624                 if (ep->e_links != NULL)
 625                         ep->e_links = &baseep[(long)ep->e_links];
 626                 if (ep->e_entries != NULL)
 627                         ep->e_entries = &baseep[(long)ep->e_entries];
 628                 if (ep->e_next != NULL)
 629                         ep->e_next = &baseep[(long)ep->e_next];
 630         }
 631 }