/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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. 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 <limits.h>
#include <stdint.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(ino_t, struct entry *);
static struct entry     *lookupparent(char *);
static void              removeentry(struct entry *);

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

        if (inum < UFS_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(ino_t inum, struct entry *np)
{
        struct entry **epp;

        if (inum < UFS_WINO || inum >= maxino)
                panic("addino: out of range %ju\n", (uintmax_t)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(ino_t inum)
{
        struct entry *next;
        struct entry **prev;

        if (inum < UFS_WINO || inum >= maxino)
                panic("deleteino: out of range %ju\n", (uintmax_t)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: %ju not found\n", (uintmax_t)inum);
}

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

        cp = name;
        for (ep = lookupino(UFS_ROOTINO); ep != NULL; ep = ep->e_entries) {
                for (np = buf; *cp != '/' && *cp != '\0' &&
                                np < &buf[sizeof(buf)]; )
                        *np++ = *cp++;
                if (np == &buf[sizeof(buf)])
                        break;
                *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(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(struct entry *ep)
{
        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(UFS_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 free list
 * headed by the following pointer.
 */
static struct entry *freelist = NULL;

/*
 * add an entry to the symbol table
 */
struct entry *
addentry(char *name, ino_t inum, int type)
{
        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 != UFS_ROOTINO || lookupino(UFS_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(UFS_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-existent 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(struct entry *ep)
{
        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(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(struct entry *ep)
{
        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
 * appropriate 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) roundup2((size) + 1, STRTBLINCR)

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(char *name)
{
        struct strhdr *np;
        size_t 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(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(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 {
        int32_t volno;
        int32_t stringsize;
        int32_t entrytblsize;
        time_t  dumptime;
        time_t  dumpdate;
        ino_t   maxino;
        int32_t ntrec;
};

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

        vprintf(stdout, "Checkpointing 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);
                done(1);
        }
        clearerr(fd);
        /*
         * Assign indices to each entry
         * Write out the string entries
         */
        for (i = UFS_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 = UFS_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(char *filename)
{
        char *base;
        long tblsize;
        struct entry *ep;
        struct entry *baseep, *lep;
        struct symtableheader hdr;
        struct stat stbuf;
        long i;
        int fd;

        vprintf(stdout, "Initialize symbol table.\n");
        if (filename == NULL) {
                entrytblsize = maxino / HASHFACTOR;
                entry = calloc((unsigned)entrytblsize, sizeof(struct entry *));
                if (entry == NULL)
                        panic("no memory for entry table\n");
                ep = addentry(".", UFS_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);
        }
        (void)close(fd);
        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];
        }
}