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symtab.c

/*
 * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * "Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
 * Reserved.  This file contains Original Code and/or Modifications of
 * Original Code as defined in and that are subject to the Apple Public
 * Source License Version 1.0 (the 'License').  You may not use this file
 * except in compliance with the License.  Please obtain a copy of the
 * License at http://www.apple.com/publicsource and read it before using
 * this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License."
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1983, 1993
 *    The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by the University of
 *    California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */


/*
 * These routines maintain the symbol table which tracks the state
 * of the file system being restored. They provide lookup by either
 * name or inode number. They also provide for creation, deletion,
 * and renaming of entries. Because of the dynamic nature of pathnames,
 * names should not be saved, but always constructed just before they
 * are needed, by calling "myname".
 */

#include <sys/param.h>
#include <sys/stat.h>

#include <ufs/ufs/dinode.h>

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "restore.h"
#include "extern.h"

/*
 * The following variables define the inode symbol table.
 * The primary hash table is dynamically allocated based on
 * the number of inodes in the file system (maxino), scaled by
 * HASHFACTOR. The variable "entry" points to the hash table;
 * the variable "entrytblsize" indicates its size (in entries).
 */
#define HASHFACTOR 5
static struct entry **entry;
static long entrytblsize;

static void        addino __P((ino_t, struct entry *));
static struct entry     *lookupparent __P((char *));
static void        removeentry __P((struct entry *));

/*
 * Look up an entry by inode number
 */
struct entry *
lookupino(inum)
      ino_t inum;
{
      register struct entry *ep;

      if (inum < WINO || inum >= maxino)
            return (NULL);
      for (ep = entry[inum % entrytblsize]; ep != NULL; ep = ep->e_next)
            if (ep->e_ino == inum)
                  return (ep);
      return (NULL);
}

/*
 * Add an entry into the entry table
 */
static void
addino(inum, np)
      ino_t inum;
      struct entry *np;
{
      struct entry **epp;

      if (inum < WINO || inum >= maxino)
            panic("addino: out of range %d\n", inum);
      epp = &entry[inum % entrytblsize];
      np->e_ino = inum;
      np->e_next = *epp;
      *epp = np;
      if (dflag)
            for (np = np->e_next; np != NULL; np = np->e_next)
                  if (np->e_ino == inum)
                        badentry(np, "duplicate inum");
}

/*
 * Delete an entry from the entry table
 */
void
deleteino(inum)
      ino_t inum;
{
      register struct entry *next;
      struct entry **prev;

      if (inum < WINO || inum >= maxino)
            panic("deleteino: out of range %d\n", inum);
      prev = &entry[inum % entrytblsize];
      for (next = *prev; next != NULL; next = next->e_next) {
            if (next->e_ino == inum) {
                  next->e_ino = 0;
                  *prev = next->e_next;
                  return;
            }
            prev = &next->e_next;
      }
      panic("deleteino: %d not found\n", inum);
}

/*
 * Look up an entry by name
 */
struct entry *
lookupname(name)
      char *name;
{
      register struct entry *ep;
      register char *np, *cp;
      char buf[MAXPATHLEN];

      cp = name;
      for (ep = lookupino(ROOTINO); ep != NULL; ep = ep->e_entries) {
            for (np = buf; *cp != '/' && *cp != '\0'; )
                  *np++ = *cp++;
            *np = '\0';
            for ( ; ep != NULL; ep = ep->e_sibling)
                  if (strcmp(ep->e_name, buf) == 0)
                        break;
            if (ep == NULL)
                  break;
            if (*cp++ == '\0')
                  return (ep);
      }
      return (NULL);
}

/*
 * Look up the parent of a pathname
 */
static struct entry *
lookupparent(name)
      char *name;
{
      struct entry *ep;
      char *tailindex;

      tailindex = strrchr(name, '/');
      if (tailindex == NULL)
            return (NULL);
      *tailindex = '\0';
      ep = lookupname(name);
      *tailindex = '/';
      if (ep == NULL)
            return (NULL);
      if (ep->e_type != NODE)
            panic("%s is not a directory\n", name);
      return (ep);
}

/*
 * Determine the current pathname of a node or leaf
 */
char *
myname(ep)
      register struct entry *ep;
{
      register char *cp;
      static char namebuf[MAXPATHLEN];

      for (cp = &namebuf[MAXPATHLEN - 2]; cp > &namebuf[ep->e_namlen]; ) {
            cp -= ep->e_namlen;
            memmove(cp, ep->e_name, (long)ep->e_namlen);
            if (ep == lookupino(ROOTINO))
                  return (cp);
            *(--cp) = '/';
            ep = ep->e_parent;
      }
      panic("%s: pathname too long\n", cp);
      return(cp);
}

/*
 * Unused symbol table entries are linked together on a freelist
 * headed by the following pointer.
 */
static struct entry *freelist = NULL;

/*
 * add an entry to the symbol table
 */
struct entry *
addentry(name, inum, type)
      char *name;
      ino_t inum;
      int type;
{
      register struct entry *np, *ep;

      if (freelist != NULL) {
            np = freelist;
            freelist = np->e_next;
            memset(np, 0, (long)sizeof(struct entry));
      } else {
            np = (struct entry *)calloc(1, sizeof(struct entry));
            if (np == NULL)
                  panic("no memory to extend symbol table\n");
      }
      np->e_type = type & ~LINK;
      ep = lookupparent(name);
      if (ep == NULL) {
            if (inum != ROOTINO || lookupino(ROOTINO) != NULL)
                  panic("bad name to addentry %s\n", name);
            np->e_name = savename(name);
            np->e_namlen = strlen(name);
            np->e_parent = np;
            addino(ROOTINO, np);
            return (np);
      }
      np->e_name = savename(strrchr(name, '/') + 1);
      np->e_namlen = strlen(np->e_name);
      np->e_parent = ep;
      np->e_sibling = ep->e_entries;
      ep->e_entries = np;
      if (type & LINK) {
            ep = lookupino(inum);
            if (ep == NULL)
                  panic("link to non-existant name\n");
            np->e_ino = inum;
            np->e_links = ep->e_links;
            ep->e_links = np;
      } else if (inum != 0) {
            if (lookupino(inum) != NULL)
                  panic("duplicate entry\n");
            addino(inum, np);
      }
      return (np);
}

/*
 * delete an entry from the symbol table
 */
void
freeentry(ep)
      register struct entry *ep;
{
      register struct entry *np;
      ino_t inum;

      if (ep->e_flags != REMOVED)
            badentry(ep, "not marked REMOVED");
      if (ep->e_type == NODE) {
            if (ep->e_links != NULL)
                  badentry(ep, "freeing referenced directory");
            if (ep->e_entries != NULL)
                  badentry(ep, "freeing non-empty directory");
      }
      if (ep->e_ino != 0) {
            np = lookupino(ep->e_ino);
            if (np == NULL)
                  badentry(ep, "lookupino failed");
            if (np == ep) {
                  inum = ep->e_ino;
                  deleteino(inum);
                  if (ep->e_links != NULL)
                        addino(inum, ep->e_links);
            } else {
                  for (; np != NULL; np = np->e_links) {
                        if (np->e_links == ep) {
                              np->e_links = ep->e_links;
                              break;
                        }
                  }
                  if (np == NULL)
                        badentry(ep, "link not found");
            }
      }
      removeentry(ep);
      freename(ep->e_name);
      ep->e_next = freelist;
      freelist = ep;
}

/*
 * Relocate an entry in the tree structure
 */
void
moveentry(ep, newname)
      register struct entry *ep;
      char *newname;
{
      struct entry *np;
      char *cp;

      np = lookupparent(newname);
      if (np == NULL)
            badentry(ep, "cannot move ROOT");
      if (np != ep->e_parent) {
            removeentry(ep);
            ep->e_parent = np;
            ep->e_sibling = np->e_entries;
            np->e_entries = ep;
      }
      cp = strrchr(newname, '/') + 1;
      freename(ep->e_name);
      ep->e_name = savename(cp);
      ep->e_namlen = strlen(cp);
      if (strcmp(gentempname(ep), ep->e_name) == 0)
            ep->e_flags |= TMPNAME;
      else
            ep->e_flags &= ~TMPNAME;
}

/*
 * Remove an entry in the tree structure
 */
static void
removeentry(ep)
      register struct entry *ep;
{
      register struct entry *np;

      np = ep->e_parent;
      if (np->e_entries == ep) {
            np->e_entries = ep->e_sibling;
      } else {
            for (np = np->e_entries; np != NULL; np = np->e_sibling) {
                  if (np->e_sibling == ep) {
                        np->e_sibling = ep->e_sibling;
                        break;
                  }
            }
            if (np == NULL)
                  badentry(ep, "cannot find entry in parent list");
      }
}

/*
 * Table of unused string entries, sorted by length.
 * 
 * Entries are allocated in STRTBLINCR sized pieces so that names
 * of similar lengths can use the same entry. The value of STRTBLINCR
 * is chosen so that every entry has at least enough space to hold
 * a "struct strtbl" header. Thus every entry can be linked onto an
 * apprpriate free list.
 *
 * NB. The macro "allocsize" below assumes that "struct strhdr"
 *     has a size that is a power of two.
 */
struct strhdr {
      struct strhdr *next;
};

#define STRTBLINCR      (sizeof(struct strhdr))
#define allocsize(size) (((size) + 1 + STRTBLINCR - 1) & ~(STRTBLINCR - 1))

static struct strhdr strtblhdr[allocsize(NAME_MAX) / STRTBLINCR];

/*
 * Allocate space for a name. It first looks to see if it already
 * has an appropriate sized entry, and if not allocates a new one.
 */
char *
savename(name)
      char *name;
{
      struct strhdr *np;
      long len;
      char *cp;

      if (name == NULL)
            panic("bad name\n");
      len = strlen(name);
      np = strtblhdr[len / STRTBLINCR].next;
      if (np != NULL) {
            strtblhdr[len / STRTBLINCR].next = np->next;
            cp = (char *)np;
      } else {
            cp = malloc((unsigned)allocsize(len));
            if (cp == NULL)
                  panic("no space for string table\n");
      }
      (void) strcpy(cp, name);
      return (cp);
}

/*
 * Free space for a name. The resulting entry is linked onto the
 * appropriate free list.
 */
void
freename(name)
      char *name;
{
      struct strhdr *tp, *np;
      
      tp = &strtblhdr[strlen(name) / STRTBLINCR];
      np = (struct strhdr *)name;
      np->next = tp->next;
      tp->next = np;
}

/*
 * Useful quantities placed at the end of a dumped symbol table.
 */
struct symtableheader {
      long  volno;
      long  stringsize;
      long  entrytblsize;
      time_t      dumptime;
      time_t      dumpdate;
      ino_t maxino;
      long  ntrec;
};

/*
 * dump a snapshot of the symbol table
 */
void
dumpsymtable(filename, checkpt)
      char *filename;
      long checkpt;
{
      register struct entry *ep, *tep;
      register ino_t i;
      struct entry temp, *tentry;
      long mynum = 1, stroff = 0;
      FILE *fd;
      struct symtableheader hdr;

      vprintf(stdout, "Check pointing the restore\n");
      if (Nflag)
            return;
      if ((fd = fopen(filename, "w")) == NULL) {
            fprintf(stderr, "fopen: %s\n", strerror(errno));
            panic("cannot create save file %s for symbol table\n",
                  filename);
      }
      clearerr(fd);
      /*
       * Assign indicies to each entry
       * Write out the string entries
       */
      for (i = WINO; i <= maxino; i++) {
            for (ep = lookupino(i); ep != NULL; ep = ep->e_links) {
                  ep->e_index = mynum++;
                  (void) fwrite(ep->e_name, sizeof(char),
                         (int)allocsize(ep->e_namlen), fd);
            }
      }
      /*
       * Convert pointers to indexes, and output
       */
      tep = &temp;
      stroff = 0;
      for (i = WINO; i <= maxino; i++) {
            for (ep = lookupino(i); ep != NULL; ep = ep->e_links) {
                  memmove(tep, ep, (long)sizeof(struct entry));
                  tep->e_name = (char *)stroff;
                  stroff += allocsize(ep->e_namlen);
                  tep->e_parent = (struct entry *)ep->e_parent->e_index;
                  if (ep->e_links != NULL)
                        tep->e_links =
                              (struct entry *)ep->e_links->e_index;
                  if (ep->e_sibling != NULL)
                        tep->e_sibling =
                              (struct entry *)ep->e_sibling->e_index;
                  if (ep->e_entries != NULL)
                        tep->e_entries =
                              (struct entry *)ep->e_entries->e_index;
                  if (ep->e_next != NULL)
                        tep->e_next =
                              (struct entry *)ep->e_next->e_index;
                  (void) fwrite((char *)tep, sizeof(struct entry), 1, fd);
            }
      }
      /*
       * Convert entry pointers to indexes, and output
       */
      for (i = 0; i < entrytblsize; i++) {
            if (entry[i] == NULL)
                  tentry = NULL;
            else
                  tentry = (struct entry *)entry[i]->e_index;
            (void) fwrite((char *)&tentry, sizeof(struct entry *), 1, fd);
      }
      hdr.volno = checkpt;
      hdr.maxino = maxino;
      hdr.entrytblsize = entrytblsize;
      hdr.stringsize = stroff;
      hdr.dumptime = dumptime;
      hdr.dumpdate = dumpdate;
      hdr.ntrec = ntrec;
      (void) fwrite((char *)&hdr, sizeof(struct symtableheader), 1, fd);
      if (ferror(fd)) {
            fprintf(stderr, "fwrite: %s\n", strerror(errno));
            panic("output error to file %s writing symbol table\n",
                  filename);
      }
      (void) fclose(fd);
}

/*
 * Initialize a symbol table from a file
 */
void
initsymtable(filename)
      char *filename;
{
      char *base;
      long tblsize;
      register struct entry *ep;
      struct entry *baseep, *lep;
      struct symtableheader hdr;
      struct stat stbuf;
      register long i;
      int fd;

      vprintf(stdout, "Initialize symbol table.\n");
      if (filename == NULL) {
            entrytblsize = maxino / HASHFACTOR;
            entry = (struct entry **)
                  calloc((unsigned)entrytblsize, sizeof(struct entry *));
            if (entry == (struct entry **)NULL)
                  panic("no memory for entry table\n");
            ep = addentry(".", ROOTINO, NODE);
            ep->e_flags |= NEW;
            return;
      }
      if ((fd = open(filename, O_RDONLY, 0)) < 0) {
            fprintf(stderr, "open: %s\n", strerror(errno));
            panic("cannot open symbol table file %s\n", filename);
      }
      if (fstat(fd, &stbuf) < 0) {
            fprintf(stderr, "stat: %s\n", strerror(errno));
            panic("cannot stat symbol table file %s\n", filename);
      }
      tblsize = stbuf.st_size - sizeof(struct symtableheader);
      base = calloc(sizeof(char), (unsigned)tblsize);
      if (base == NULL)
            panic("cannot allocate space for symbol table\n");
      if (read(fd, base, (int)tblsize) < 0 ||
          read(fd, (char *)&hdr, sizeof(struct symtableheader)) < 0) {
            fprintf(stderr, "read: %s\n", strerror(errno));
            panic("cannot read symbol table file %s\n", filename);
      }
      switch (command) {
      case 'r':
            /*
             * For normal continuation, insure that we are using
             * the next incremental tape
             */
            if (hdr.dumpdate != dumptime) {
                  if (hdr.dumpdate < dumptime)
                        fprintf(stderr, "Incremental tape too low\n");
                  else
                        fprintf(stderr, "Incremental tape too high\n");
                  done(1);
            }
            break;
      case 'R':
            /*
             * For restart, insure that we are using the same tape
             */
            curfile.action = SKIP;
            dumptime = hdr.dumptime;
            dumpdate = hdr.dumpdate;
            if (!bflag)
                  newtapebuf(hdr.ntrec);
            getvol(hdr.volno);
            break;
      default:
            panic("initsymtable called from command %c\n", command);
            break;
      }
      maxino = hdr.maxino;
      entrytblsize = hdr.entrytblsize;
      entry = (struct entry **)
            (base + tblsize - (entrytblsize * sizeof(struct entry *)));
      baseep = (struct entry *)(base + hdr.stringsize - sizeof(struct entry));
      lep = (struct entry *)entry;
      for (i = 0; i < entrytblsize; i++) {
            if (entry[i] == NULL)
                  continue;
            entry[i] = &baseep[(long)entry[i]];
      }
      for (ep = &baseep[1]; ep < lep; ep++) {
            ep->e_name = base + (long)ep->e_name;
            ep->e_parent = &baseep[(long)ep->e_parent];
            if (ep->e_sibling != NULL)
                  ep->e_sibling = &baseep[(long)ep->e_sibling];
            if (ep->e_links != NULL)
                  ep->e_links = &baseep[(long)ep->e_links];
            if (ep->e_entries != NULL)
                  ep->e_entries = &baseep[(long)ep->e_entries];
            if (ep->e_next != NULL)
                  ep->e_next = &baseep[(long)ep->e_next];
      }
}

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