BSD 4_3_Net_2 release

[unix-history] / usr / src / sbin / restore / symtab.c

/*
* Copyright (c) 1983 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.
*/

#ifndef lint
static char sccsid[] = "@(#)symtab.c    5.5 (Berkeley) 6/1/90";
#endif /* not lint */

/*
* 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 "restore.h"
#include <sys/stat.h>
#include <ufs/dir.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;

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

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

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

       if (inum < ROOTINO || 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 != NIL; np = np->e_next)
                       if (np->e_ino == inum)
                               badentry(np, "duplicate inum");
}

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

       if (inum < ROOTINO || inum >= maxino)
               panic("deleteino: out of range %d\n", inum);
       prev = &entry[inum % entrytblsize];
       for (next = *prev; next != NIL; 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 != NIL; ep = ep->e_entries) {
               for (np = buf; *cp != '/' && *cp != '\0'; )
                       *np++ = *cp++;
               *np = '\0';
               for ( ; ep != NIL; ep = ep->e_sibling)
                       if (strcmp(ep->e_name, buf) == 0)
                               break;
               if (ep == NIL)
                       break;
               if (*cp++ == '\0')
                       return (ep);
       }
       return (NIL);
}

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

       tailindex = rindex(name, '/');
       if (tailindex == 0)
               return (NIL);
       *tailindex = '\0';
       ep = lookupname(name);
       *tailindex = '/';
       if (ep == NIL)
               return (NIL);
       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;
               bcopy(ep->e_name, cp, (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 = NIL;

/*
* 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 != NIL) {
               np = freelist;
               freelist = np->e_next;
               bzero((char *)np, (long)sizeof(struct entry));
       } else {
               np = (struct entry *)calloc(1, sizeof(struct entry));
               if (np == NIL)
                       panic("no memory to extend symbol table\n");
       }
       np->e_type = type & ~LINK;
       ep = lookupparent(name);
       if (ep == NIL) {
               if (inum != ROOTINO || lookupino(ROOTINO) != NIL)
                       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(rindex(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 == NIL)
                       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) != NIL)
                       panic("duplicate entry\n");
               addino(inum, np);
       }
       return (np);
}

/*
* delete an entry from the symbol table
*/
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 != NIL)
                       badentry(ep, "freeing referenced directory");
               if (ep->e_entries != NIL)
                       badentry(ep, "freeing non-empty directory");
       }
       if (ep->e_ino != 0) {
               np = lookupino(ep->e_ino);
               if (np == NIL)
                       badentry(ep, "lookupino failed");
               if (np == ep) {
                       inum = ep->e_ino;
                       deleteino(inum);
                       if (ep->e_links != NIL)
                               addino(inum, ep->e_links);
               } else {
                       for (; np != NIL; np = np->e_links) {
                               if (np->e_links == ep) {
                                       np->e_links = ep->e_links;
                                       break;
                               }
                       }
                       if (np == NIL)
                               badentry(ep, "link not found");
               }
       }
       removeentry(ep);
       freename(ep->e_name);
       ep->e_next = freelist;
       freelist = ep;
}

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

       np = lookupparent(newname);
       if (np == NIL)
               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 = rindex(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
*/
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 != NIL; np = np->e_sibling) {
                       if (np->e_sibling == ep) {
                               np->e_sibling = ep->e_sibling;
                               break;
                       }
               }
               if (np == NIL)
                       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(MAXNAMLEN) / 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.
*/
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
*/
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) {
               perror("fopen");
               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 = ROOTINO; i < maxino; i++) {
               for (ep = lookupino(i); ep != NIL; 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 = ROOTINO; i < maxino; i++) {
               for (ep = lookupino(i); ep != NIL; ep = ep->e_links) {
                       bcopy((char *)ep, (char *)tep,
                               (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 != NIL)
                               tep->e_links =
                                       (struct entry *)ep->e_links->e_index;
                       if (ep->e_sibling != NIL)
                               tep->e_sibling =
                                       (struct entry *)ep->e_sibling->e_index;
                       if (ep->e_entries != NIL)
                               tep->e_entries =
                                       (struct entry *)ep->e_entries->e_index;
                       if (ep->e_next != NIL)
                               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] == NIL)
                       tentry = NIL;
               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)) {
               perror("fwrite");
               panic("output error to file %s writing symbol table\n",
                       filename);
       }
       (void) fclose(fd);
}

/*
* Initialize a symbol table from a file
*/
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 **)NIL)
                       panic("no memory for entry table\n");
               ep = addentry(".", ROOTINO, NODE);
               ep->e_flags |= NEW;
               return;
       }
       if ((fd = open(filename, 0)) < 0) {
               perror("open");
               panic("cannot open symbol table file %s\n", filename);
       }
       if (fstat(fd, &stbuf) < 0) {
               perror("stat");
               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) {
               perror("read");
               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] == NIL)
                       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 != NIL)
                       ep->e_sibling = &baseep[(long)ep->e_sibling];
               if (ep->e_links != NIL)
                       ep->e_links = &baseep[(long)ep->e_links];
               if (ep->e_entries != NIL)
                       ep->e_entries = &baseep[(long)ep->e_entries];
               if (ep->e_next != NIL)
                       ep->e_next = &baseep[(long)ep->e_next];
       }
}