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>, 1999-2000
   6  */
   7
   8 /*
   9  * Copyright (c) 1983, 1993
  10  *      The Regents of the University of California.  All rights reserved.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. All advertising materials mentioning features or use of this software
  21  *    must display the following acknowledgement:
  22  *      This product includes software developed by the University of
  23  *      California, Berkeley and its contributors.
  24  * 4. Neither the name of the University nor the names of its contributors
  25  *    may be used to endorse or promote products derived from this software
  26  *    without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38  * SUCH DAMAGE.
  39  */
  40
  41 #ifndef lint
  42 static const char rcsid[] =
  43         "$Id: symtab.c,v 1.8 2000/03/01 10:16:05 stelian Exp $";
  44 #endif /* not lint */
  45
  46 /*
  47  * These routines maintain the symbol table which tracks the state
  48  * of the file system being restored. They provide lookup by either
  49  * name or inode number. They also provide for creation, deletion,
  50  * and renaming of entries. Because of the dynamic nature of pathnames,
  51  * names should not be saved, but always constructed just before they
  52  * are needed, by calling "myname".
  53  */
  54
  55 #include <sys/param.h>
  56 #include <sys/stat.h>
  57
  58 #ifdef  __linux__
  59 #include <sys/time.h>
  60 #include <linux/ext2_fs.h>
  61 #include <bsdcompat.h>
  62 #else   /* __linux__ */
  63 #include <ufs/ufs/dinode.h>
  64 #endif  /* __linux__ */
  65
  66 #include <errno.h>
  67 #include <compaterr.h>
  68 #include <fcntl.h>
  69 #include <stdio.h>
  70 #include <stdlib.h>
  71 #include <string.h>
  72 #include <unistd.h>
  73
  74 #ifdef  __linux__
  75 #include <ext2fs/ext2fs.h>
  76 #endif
  77
  78 #include "restore.h"
  79 #include "extern.h"
  80
  81 /*
  82  * The following variables define the inode symbol table.
  83  * The primary hash table is dynamically allocated based on
  84  * the number of inodes in the file system (maxino), scaled by
  85  * HASHFACTOR. The variable "entry" points to the hash table;
  86  * the variable "entrytblsize" indicates its size (in entries).
  87  */
  88 #define HASHFACTOR 5
  89 static struct entry **entry;
  90 static long entrytblsize;
  91
  92 static void              addino __P((ino_t, struct entry *));
  93 static struct entry     *lookupparent __P((char *));
  94 static void              removeentry __P((struct entry *));
  95
  96 /*
  97  * Look up an entry by inode number
  98  */
  99 struct entry *
 100 lookupino(ino_t inum)
 101 {
 102         register struct entry *ep;
 103
 104         if (inum < WINO || inum >= maxino)
 105                 return (NULL);
 106         for (ep = entry[inum % entrytblsize]; ep != NULL; ep = ep->e_next)
 107                 if (ep->e_ino == inum)
 108                         return (ep);
 109         return (NULL);
 110 }
 111
 112 /*
 113  * Add an entry into the entry table
 114  */
 115 static void
 116 addino(ino_t inum, struct entry *np)
 117 {
 118         struct entry **epp;
 119
 120         if (inum < WINO || inum >= maxino)
 121                 panic("addino: out of range %d\n", inum);
 122         epp = &entry[inum % entrytblsize];
 123         np->e_ino = inum;
 124         np->e_next = *epp;
 125         *epp = np;
 126         if (dflag)
 127                 for (np = np->e_next; np != NULL; np = np->e_next)
 128                         if (np->e_ino == inum)
 129                                 badentry(np, "duplicate inum");
 130 }
 131
 132 /*
 133  * Delete an entry from the entry table
 134  */
 135 void
 136 deleteino(ino_t inum)
 137 {
 138         register struct entry *next;
 139         struct entry **prev;
 140
 141         if (inum < WINO || inum >= maxino)
 142                 panic("deleteino: out of range %d\n", inum);
 143         prev = &entry[inum % entrytblsize];
 144         for (next = *prev; next != NULL; next = next->e_next) {
 145                 if (next->e_ino == inum) {
 146                         next->e_ino = 0;
 147                         *prev = next->e_next;
 148                         return;
 149                 }
 150                 prev = &next->e_next;
 151         }
 152         panic("deleteino: %d not found\n", inum);
 153 }
 154
 155 /*
 156  * Look up an entry by name
 157  */
 158 struct entry *
 159 lookupname(char *name)
 160 {
 161         register struct entry *ep;
 162         register char *np, *cp;
 163         char buf[MAXPATHLEN];
 164
 165         cp = name;
 166         for (ep = lookupino(ROOTINO); ep != NULL; ep = ep->e_entries) {
 167                 for (np = buf; *cp != '/' && *cp != '\0' &&
 168                                 np < &buf[sizeof(buf)]; )
 169                         *np++ = *cp++;
 170                 if (np == &buf[sizeof(buf)])
 171                         break;
 172                 *np = '\0';
 173                 for ( ; ep != NULL; ep = ep->e_sibling)
 174                         if (strcmp(ep->e_name, buf) == 0)
 175                                 break;
 176                 if (ep == NULL)
 177                         break;
 178                 if (*cp++ == '\0')
 179                         return (ep);
 180         }
 181         return (NULL);
 182 }
 183
 184 /*
 185  * Look up the parent of a pathname
 186  */
 187 static struct entry *
 188 lookupparent(char *name)
 189 {
 190         struct entry *ep;
 191         char *tailindex;
 192
 193         tailindex = strrchr(name, '/');
 194         if (tailindex == NULL)
 195                 return (NULL);
 196         *tailindex = '\0';
 197         ep = lookupname(name);
 198         *tailindex = '/';
 199         if (ep == NULL)
 200                 return (NULL);
 201         if (ep->e_type != NODE)
 202                 panic("%s is not a directory\n", name);
 203         return (ep);
 204 }
 205
 206 /*
 207  * Determine the current pathname of a node or leaf
 208  */
 209 char *
 210 myname(struct entry *ep)
 211 {
 212         register char *cp;
 213         static char namebuf[MAXPATHLEN];
 214
 215         for (cp = &namebuf[MAXPATHLEN - 2]; cp > &namebuf[ep->e_namlen]; ) {
 216                 cp -= ep->e_namlen;
 217                 memmove(cp, ep->e_name, (size_t)ep->e_namlen);
 218                 if (ep == lookupino(ROOTINO))
 219                         return (cp);
 220                 *(--cp) = '/';
 221                 ep = ep->e_parent;
 222         }
 223         panic("%s: pathname too long\n", cp);
 224         return(cp);
 225 }
 226
 227 /*
 228  * Unused symbol table entries are linked together on a free list
 229  * headed by the following pointer.
 230  */
 231 static struct entry *freelist = NULL;
 232
 233 /*
 234  * add an entry to the symbol table
 235  */
 236 struct entry *
 237 addentry(char *name, ino_t inum, int type)
 238 {
 239         register struct entry *np, *ep;
 240
 241         if (freelist != NULL) {
 242                 np = freelist;
 243                 freelist = np->e_next;
 244                 memset(np, 0, sizeof(struct entry));
 245         } else {
 246                 np = (struct entry *)calloc(1, sizeof(struct entry));
 247                 if (np == NULL)
 248                         panic("no memory to extend symbol table\n");
 249         }
 250         np->e_type = type & ~LINK;
 251         ep = lookupparent(name);
 252         if (ep == NULL) {
 253                 if (inum != ROOTINO || lookupino(ROOTINO) != NULL)
 254                         panic("bad name to addentry %s\n", name);
 255                 np->e_name = savename(name);
 256                 np->e_namlen = strlen(name);
 257                 np->e_parent = np;
 258                 addino(ROOTINO, np);
 259                 return (np);
 260         }
 261         np->e_name = savename(strrchr(name, '/') + 1);
 262         np->e_namlen = strlen(np->e_name);
 263         np->e_parent = ep;
 264         np->e_sibling = ep->e_entries;
 265         ep->e_entries = np;
 266         if (type & LINK) {
 267                 ep = lookupino(inum);
 268                 if (ep == NULL)
 269                         panic("link to non-existent name\n");
 270                 np->e_ino = inum;
 271                 np->e_links = ep->e_links;
 272                 ep->e_links = np;
 273         } else if (inum != 0) {
 274                 if (lookupino(inum) != NULL)
 275                         panic("duplicate entry\n");
 276                 addino(inum, np);
 277         }
 278         return (np);
 279 }
 280
 281 /*
 282  * delete an entry from the symbol table
 283  */
 284 void
 285 freeentry(struct entry *ep)
 286 {
 287         register struct entry *np;
 288         ino_t inum;
 289
 290         if (ep->e_flags != REMOVED)
 291                 badentry(ep, "not marked REMOVED");
 292         if (ep->e_type == NODE) {
 293                 if (ep->e_links != NULL)
 294                         badentry(ep, "freeing referenced directory");
 295                 if (ep->e_entries != NULL)
 296                         badentry(ep, "freeing non-empty directory");
 297         }
 298         if (ep->e_ino != 0) {
 299                 np = lookupino(ep->e_ino);
 300                 if (np == NULL)
 301                         badentry(ep, "lookupino failed");
 302                 if (np == ep) {
 303                         inum = ep->e_ino;
 304                         deleteino(inum);
 305                         if (ep->e_links != NULL)
 306                                 addino(inum, ep->e_links);
 307                 } else {
 308                         for (; np != NULL; np = np->e_links) {
 309                                 if (np->e_links == ep) {
 310                                         np->e_links = ep->e_links;
 311                                         break;
 312                                 }
 313                         }
 314                         if (np == NULL)
 315                                 badentry(ep, "link not found");
 316                 }
 317         }
 318         removeentry(ep);
 319         freename(ep->e_name);
 320         ep->e_next = freelist;
 321         freelist = ep;
 322 }
 323
 324 /*
 325  * Relocate an entry in the tree structure
 326  */
 327 void
 328 moveentry(struct entry *ep, char *newname)
 329 {
 330         struct entry *np;
 331         char *cp;
 332
 333         np = lookupparent(newname);
 334         if (np == NULL)
 335                 badentry(ep, "cannot move ROOT");
 336         if (np != ep->e_parent) {
 337                 removeentry(ep);
 338                 ep->e_parent = np;
 339                 ep->e_sibling = np->e_entries;
 340                 np->e_entries = ep;
 341         }
 342         cp = strrchr(newname, '/') + 1;
 343         freename(ep->e_name);
 344         ep->e_name = savename(cp);
 345         ep->e_namlen = strlen(cp);
 346         if (strcmp(gentempname(ep), ep->e_name) == 0)
 347                 ep->e_flags |= TMPNAME;
 348         else
 349                 ep->e_flags &= ~TMPNAME;
 350 }
 351
 352 /*
 353  * Remove an entry in the tree structure
 354  */
 355 static void
 356 removeentry(struct entry *ep)
 357 {
 358         register struct entry *np;
 359
 360         np = ep->e_parent;
 361         if (np->e_entries == ep) {
 362                 np->e_entries = ep->e_sibling;
 363         } else {
 364                 for (np = np->e_entries; np != NULL; np = np->e_sibling) {
 365                         if (np->e_sibling == ep) {
 366                                 np->e_sibling = ep->e_sibling;
 367                                 break;
 368                         }
 369                 }
 370                 if (np == NULL)
 371                         badentry(ep, "cannot find entry in parent list");
 372         }
 373 }
 374
 375 /*
 376  * Table of unused string entries, sorted by length.
 377  *
 378  * Entries are allocated in STRTBLINCR sized pieces so that names
 379  * of similar lengths can use the same entry. The value of STRTBLINCR
 380  * is chosen so that every entry has at least enough space to hold
 381  * a "struct strtbl" header. Thus every entry can be linked onto an
 382  * appropriate free list.
 383  *
 384  * NB. The macro "allocsize" below assumes that "struct strhdr"
 385  *     has a size that is a power of two.
 386  */
 387 struct strhdr {
 388         struct strhdr *next;
 389 };
 390
 391 #define STRTBLINCR      (sizeof(struct strhdr))
 392 #define allocsize(size) (((size) + 1 + STRTBLINCR - 1) & ~(STRTBLINCR - 1))
 393
 394 static struct strhdr strtblhdr[allocsize(MAXNAMLEN) / STRTBLINCR];
 395
 396 /*
 397  * Allocate space for a name. It first looks to see if it already
 398  * has an appropriate sized entry, and if not allocates a new one.
 399  */
 400 char *
 401 savename(char *name)
 402 {
 403         struct strhdr *np;
 404         long len;
 405         char *cp;
 406
 407         if (name == NULL)
 408                 panic("bad name\n");
 409         len = strlen(name);
 410         np = strtblhdr[len / STRTBLINCR].next;
 411         if (np != NULL) {
 412                 strtblhdr[len / STRTBLINCR].next = np->next;
 413                 cp = (char *)np;
 414         } else {
 415                 cp = malloc((unsigned)allocsize(len));
 416                 if (cp == NULL)
 417                         panic("no space for string table\n");
 418         }
 419         (void) strcpy(cp, name);
 420         return (cp);
 421 }
 422
 423 /*
 424  * Free space for a name. The resulting entry is linked onto the
 425  * appropriate free list.
 426  */
 427 void
 428 freename(char *name)
 429 {
 430         struct strhdr *tp, *np;
 431
 432         tp = &strtblhdr[strlen(name) / STRTBLINCR];
 433         np = (struct strhdr *)name;
 434         np->next = tp->next;
 435         tp->next = np;
 436 }
 437
 438 /*
 439  * Useful quantities placed at the end of a dumped symbol table.
 440  */
 441 struct symtableheader {
 442         int32_t volno;
 443         int32_t stringsize;
 444         int32_t entrytblsize;
 445         time_t  dumptime;
 446         time_t  dumpdate;
 447         ino_t   maxino;
 448         int32_t ntrec;
 449 };
 450
 451 /*
 452  * dump a snapshot of the symbol table
 453  */
 454 void
 455 dumpsymtable(char *filename, long checkpt)
 456 {
 457         register struct entry *ep, *tep;
 458         register ino_t i;
 459         struct entry temp, *tentry;
 460         long mynum = 1, stroff = 0;
 461         FILE *fd;
 462         struct symtableheader hdr;
 463
 464         Vprintf(stdout, "Check pointing the restore\n");
 465         if (Nflag)
 466                 return;
 467         if ((fd = fopen(filename, "w")) == NULL) {
 468                 warn("fopen");
 469                 panic("cannot create save file %s for symbol table\n",
 470                         filename);
 471         }
 472         clearerr(fd);
 473         /*
 474          * Assign indices to each entry
 475          * Write out the string entries
 476          */
 477         for (i = WINO; i <= maxino; i++) {
 478                 for (ep = lookupino(i); ep != NULL; ep = ep->e_links) {
 479                         ep->e_index = mynum++;
 480                         (void) fwrite(ep->e_name, sizeof(char),
 481                                (int)allocsize(ep->e_namlen), fd);
 482                 }
 483         }
 484         /*
 485          * Convert pointers to indexes, and output
 486          */
 487         tep = &temp;
 488         stroff = 0;
 489         for (i = WINO; i <= maxino; i++) {
 490                 for (ep = lookupino(i); ep != NULL; ep = ep->e_links) {
 491                         memmove(tep, ep, sizeof(struct entry));
 492                         tep->e_name = (char *)stroff;
 493                         stroff += allocsize(ep->e_namlen);
 494                         tep->e_parent = (struct entry *)ep->e_parent->e_index;
 495                         if (ep->e_links != NULL)
 496                                 tep->e_links =
 497                                         (struct entry *)ep->e_links->e_index;
 498                         if (ep->e_sibling != NULL)
 499                                 tep->e_sibling =
 500                                         (struct entry *)ep->e_sibling->e_index;
 501                         if (ep->e_entries != NULL)
 502                                 tep->e_entries =
 503                                         (struct entry *)ep->e_entries->e_index;
 504                         if (ep->e_next != NULL)
 505                                 tep->e_next =
 506                                         (struct entry *)ep->e_next->e_index;
 507                         (void) fwrite((char *)tep, sizeof(struct entry), 1, fd);
 508                 }
 509         }
 510         /*
 511          * Convert entry pointers to indexes, and output
 512          */
 513         for (i = 0; i < entrytblsize; i++) {
 514                 if (entry[i] == NULL)
 515                         tentry = NULL;
 516                 else
 517                         tentry = (struct entry *)entry[i]->e_index;
 518                 (void) fwrite((char *)&tentry, sizeof(struct entry *), 1, fd);
 519         }
 520         hdr.volno = checkpt;
 521         hdr.maxino = maxino;
 522         hdr.entrytblsize = entrytblsize;
 523         hdr.stringsize = stroff;
 524         hdr.dumptime = dumptime;
 525         hdr.dumpdate = dumpdate;
 526         hdr.ntrec = ntrec;
 527         (void) fwrite((char *)&hdr, sizeof(struct symtableheader), 1, fd);
 528         if (ferror(fd)) {
 529                 warn("fwrite");
 530                 panic("output error to file %s writing symbol table\n",
 531                         filename);
 532         }
 533         (void) fclose(fd);
 534 }
 535
 536 /*
 537  * Initialize a symbol table from a file
 538  */
 539 void
 540 initsymtable(char *filename)
 541 {
 542         char *base;
 543         long tblsize;
 544         register struct entry *ep;
 545         struct entry *baseep, *lep;
 546         struct symtableheader hdr;
 547         struct stat stbuf;
 548         register long i;
 549         int fd;
 550
 551         Vprintf(stdout, "Initialize symbol table.\n");
 552         if (filename == NULL) {
 553                 entrytblsize = maxino / HASHFACTOR;
 554                 entry = (struct entry **)
 555                         calloc((unsigned)entrytblsize, sizeof(struct entry *));
 556                 if (entry == (struct entry **)NULL)
 557                         panic("no memory for entry table\n");
 558                 ep = addentry(".", ROOTINO, NODE);
 559                 ep->e_flags |= NEW;
 560                 return;
 561         }
 562         if ((fd = open(filename, O_RDONLY, 0)) < 0) {
 563                 warn("open");
 564                 panic("cannot open symbol table file %s\n", filename);
 565         }
 566         if (fstat(fd, &stbuf) < 0) {
 567                 warn("stat");
 568                 panic("cannot stat symbol table file %s\n", filename);
 569         }
 570         tblsize = stbuf.st_size - sizeof(struct symtableheader);
 571         base = calloc(sizeof(char), (unsigned)tblsize);
 572         if (base == NULL)
 573                 panic("cannot allocate space for symbol table\n");
 574         if (read(fd, base, (int)tblsize) < 0 ||
 575             read(fd, (char *)&hdr, sizeof(struct symtableheader)) < 0) {
 576                 warn("read");
 577                 panic("cannot read symbol table file %s\n", filename);
 578         }
 579         switch (command) {
 580         case 'r':
 581                 /*
 582                  * For normal continuation, insure that we are using
 583                  * the next incremental tape
 584                  */
 585                 if (hdr.dumpdate != dumptime)
 586                         errx(1, "Incremental tape too %s",
 587                                 (hdr.dumpdate < dumptime) ? "low" : "high");
 588                 break;
 589         case 'R':
 590                 /*
 591                  * For restart, insure that we are using the same tape
 592                  */
 593                 curfile.action = SKIP;
 594                 dumptime = hdr.dumptime;
 595                 dumpdate = hdr.dumpdate;
 596                 if (!bflag)
 597                         newtapebuf(hdr.ntrec);
 598                 getvol(hdr.volno);
 599                 break;
 600         default:
 601                 panic("initsymtable called from command %c\n", command);
 602                 break;
 603         }
 604         maxino = hdr.maxino;
 605         entrytblsize = hdr.entrytblsize;
 606         entry = (struct entry **)
 607                 (base + tblsize - (entrytblsize * sizeof(struct entry *)));
 608         baseep = (struct entry *)(base + hdr.stringsize - sizeof(struct entry));
 609         lep = (struct entry *)entry;
 610         for (i = 0; i < entrytblsize; i++) {
 611                 if (entry[i] == NULL)
 612                         continue;
 613                 entry[i] = &baseep[(long)entry[i]];
 614         }
 615         for (ep = &baseep[1]; ep < lep; ep++) {
 616                 ep->e_name = base + (long)ep->e_name;
 617                 ep->e_parent = &baseep[(long)ep->e_parent];
 618                 if (ep->e_sibling != NULL)
 619                         ep->e_sibling = &baseep[(long)ep->e_sibling];
 620                 if (ep->e_links != NULL)
 621                         ep->e_links = &baseep[(long)ep->e_links];
 622                 if (ep->e_entries != NULL)
 623                         ep->e_entries = &baseep[(long)ep->e_entries];
 624                 if (ep->e_next != NULL)
 625                         ep->e_next = &baseep[(long)ep->e_next];
 626         }
 627 }