db_vrfyutil.c

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 2000-2005
 *      Sleepycat Software.  All rights reserved.
 *
 * $Id: db_vrfyutil.c,v 12.5 2005/06/16 20:21:15 bostic Exp $
 */

#include "db_config.h"

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#include <string.h>
#endif

#include "db_int.h"
#include "dbinc/db_page.h"
#include "dbinc/db_verify.h"
#include "dbinc/db_am.h"

static int __db_vrfy_childinc __P((DBC *, VRFY_CHILDINFO *));
static int __db_vrfy_pageinfo_create __P((DB_ENV *, VRFY_PAGEINFO **));

/*
 * __db_vrfy_dbinfo_create --
 *      Allocate and initialize a VRFY_DBINFO structure.
 *
 * PUBLIC: int __db_vrfy_dbinfo_create
 * PUBLIC:     __P((DB_ENV *, u_int32_t, VRFY_DBINFO **));
 */
int
__db_vrfy_dbinfo_create(dbenv, pgsize, vdpp)
        DB_ENV *dbenv;
        u_int32_t pgsize;
        VRFY_DBINFO **vdpp;
{
        DB *cdbp, *pgdbp, *pgset;
        VRFY_DBINFO *vdp;
        int ret;

        vdp = NULL;
        cdbp = pgdbp = pgset = NULL;

        if ((ret = __os_calloc(NULL, 1, sizeof(VRFY_DBINFO), &vdp)) != 0)
                goto err;

        if ((ret = db_create(&cdbp, dbenv, 0)) != 0)
                goto err;

        if ((ret = __db_set_flags(cdbp, DB_DUP)) != 0)
                goto err;

        if ((ret = __db_set_pagesize(cdbp, pgsize)) != 0)
                goto err;

        if ((ret = __db_open(cdbp,
            NULL, NULL, NULL, DB_BTREE, DB_CREATE, 0600, PGNO_BASE_MD)) != 0)
                goto err;

        if ((ret = db_create(&pgdbp, dbenv, 0)) != 0)
                goto err;

        if ((ret = __db_set_pagesize(pgdbp, pgsize)) != 0)
                goto err;

        if ((ret = __db_open(pgdbp,
            NULL, NULL, NULL, DB_BTREE, DB_CREATE, 0600, PGNO_BASE_MD)) != 0)
                goto err;

        if ((ret = __db_vrfy_pgset(dbenv, pgsize, &pgset)) != 0)
                goto err;

        LIST_INIT(&vdp->subdbs);
        LIST_INIT(&vdp->activepips);

        vdp->cdbp = cdbp;
        vdp->pgdbp = pgdbp;
        vdp->pgset = pgset;
        *vdpp = vdp;
        return (0);

err:    if (cdbp != NULL)
                (void)__db_close(cdbp, NULL, 0);
        if (pgdbp != NULL)
                (void)__db_close(pgdbp, NULL, 0);
        if (vdp != NULL)
                __os_free(dbenv, vdp);
        return (ret);
}

/*
 * __db_vrfy_dbinfo_destroy --
 *      Destructor for VRFY_DBINFO.  Destroys VRFY_PAGEINFOs and deallocates
 *      structure.
 *
 * PUBLIC: int __db_vrfy_dbinfo_destroy __P((DB_ENV *, VRFY_DBINFO *));
 */
int
__db_vrfy_dbinfo_destroy(dbenv, vdp)
        DB_ENV *dbenv;
        VRFY_DBINFO *vdp;
{
        VRFY_CHILDINFO *c;
        int t_ret, ret;

        ret = 0;

        /*
         * Discard active page structures.  Ideally there wouldn't be any,
         * but in some error cases we may not have cleared them all out.
         */
        while (LIST_FIRST(&vdp->activepips) != NULL)
                if ((t_ret = __db_vrfy_putpageinfo(
                    dbenv, vdp, LIST_FIRST(&vdp->activepips))) != 0) {
                        if (ret == 0)
                                ret = t_ret;
                        break;
                }

        /* Discard subdatabase list structures. */
        while ((c = LIST_FIRST(&vdp->subdbs)) != NULL) {
                LIST_REMOVE(c, links);
                __os_free(NULL, c);
        }

        if ((t_ret = __db_close(vdp->pgdbp, NULL, 0)) != 0)
                ret = t_ret;

        if ((t_ret = __db_close(vdp->cdbp, NULL, 0)) != 0 && ret == 0)
                ret = t_ret;

        if ((t_ret = __db_close(vdp->pgset, NULL, 0)) != 0 && ret == 0)
                ret = t_ret;

        if (vdp->extents != NULL)
                __os_free(dbenv, vdp->extents);
        __os_free(dbenv, vdp);
        return (ret);
}

/*
 * __db_vrfy_getpageinfo --
 *      Get a PAGEINFO structure for a given page, creating it if necessary.
 *
 * PUBLIC: int __db_vrfy_getpageinfo
 * PUBLIC:     __P((VRFY_DBINFO *, db_pgno_t, VRFY_PAGEINFO **));
 */
int
__db_vrfy_getpageinfo(vdp, pgno, pipp)
        VRFY_DBINFO *vdp;
        db_pgno_t pgno;
        VRFY_PAGEINFO **pipp;
{
        DBT key, data;
        DB *pgdbp;
        VRFY_PAGEINFO *pip;
        int ret;

        /*
         * We want a page info struct.  There are three places to get it from,
         * in decreasing order of preference:
         *
         * 1. vdp->activepips.  If it's already "checked out", we're
         *      already using it, we return the same exact structure with a
         *      bumped refcount.  This is necessary because this code is
         *      replacing array accesses, and it's common for f() to make some
         *      changes to a pip, and then call g() and h() which each make
         *      changes to the same pip.  vdps are never shared between threads
         *      (they're never returned to the application), so this is safe.
         * 2. The pgdbp.  It's not in memory, but it's in the database, so
         *      get it, give it a refcount of 1, and stick it on activepips.
         * 3. malloc.  It doesn't exist yet;  create it, then stick it on
         *      activepips.  We'll put it in the database when we putpageinfo
         *      later.
         */

        /* Case 1. */
        for (pip = LIST_FIRST(&vdp->activepips); pip != NULL;
            pip = LIST_NEXT(pip, links))
                if (pip->pgno == pgno)
                        /* Found it. */
                        goto found;

        /* Case 2. */
        pgdbp = vdp->pgdbp;
        memset(&key, 0, sizeof(DBT));
        memset(&data, 0, sizeof(DBT));
        F_SET(&data, DB_DBT_MALLOC);
        key.data = &pgno;
        key.size = sizeof(db_pgno_t);

        if ((ret = __db_get(pgdbp, NULL, &key, &data, 0)) == 0) {
                /* Found it. */
                DB_ASSERT(data.size == sizeof(VRFY_PAGEINFO));
                pip = data.data;
                LIST_INSERT_HEAD(&vdp->activepips, pip, links);
                goto found;
        } else if (ret != DB_NOTFOUND)  /* Something nasty happened. */
                return (ret);

        /* Case 3 */
        if ((ret = __db_vrfy_pageinfo_create(pgdbp->dbenv, &pip)) != 0)
                return (ret);

        LIST_INSERT_HEAD(&vdp->activepips, pip, links);
found:  pip->pi_refcount++;

        *pipp = pip;
        return (0);
}

/*
 * __db_vrfy_putpageinfo --
 *      Put back a VRFY_PAGEINFO that we're done with.
 *
 * PUBLIC: int __db_vrfy_putpageinfo __P((DB_ENV *,
 * PUBLIC:     VRFY_DBINFO *, VRFY_PAGEINFO *));
 */
int
__db_vrfy_putpageinfo(dbenv, vdp, pip)
        DB_ENV *dbenv;
        VRFY_DBINFO *vdp;
        VRFY_PAGEINFO *pip;
{
        DBT key, data;
        DB *pgdbp;
        VRFY_PAGEINFO *p;
        int ret;

        if (--pip->pi_refcount > 0)
                return (0);

        pgdbp = vdp->pgdbp;
        memset(&key, 0, sizeof(DBT));
        memset(&data, 0, sizeof(DBT));

        key.data = &pip->pgno;
        key.size = sizeof(db_pgno_t);
        data.data = pip;
        data.size = sizeof(VRFY_PAGEINFO);

        if ((ret = __db_put(pgdbp, NULL, &key, &data, 0)) != 0)
                return (ret);

        for (p =
            LIST_FIRST(&vdp->activepips); p != NULL; p = LIST_NEXT(p, links))
                if (p == pip)
                        break;
        if (p != NULL)
                LIST_REMOVE(p, links);

        __os_ufree(dbenv, p);
        return (0);
}

/*
 * __db_vrfy_pgset --
 *      Create a temporary database for the storing of sets of page numbers.
 *      (A mapping from page number to int, used by the *_meta2pgset functions,
 *      as well as for keeping track of which pages the verifier has seen.)
 *
 * PUBLIC: int __db_vrfy_pgset __P((DB_ENV *, u_int32_t, DB **));
 */
int
__db_vrfy_pgset(dbenv, pgsize, dbpp)
        DB_ENV *dbenv;
        u_int32_t pgsize;
        DB **dbpp;
{
        DB *dbp;
        int ret;

        if ((ret = db_create(&dbp, dbenv, 0)) != 0)
                return (ret);
        if ((ret = __db_set_pagesize(dbp, pgsize)) != 0)
                goto err;
        if ((ret = __db_open(dbp,
            NULL, NULL, NULL, DB_BTREE, DB_CREATE, 0600, PGNO_BASE_MD)) == 0)
                *dbpp = dbp;
        else
err:            (void)__db_close(dbp, NULL, 0);

        return (ret);
}

/*
 * __db_vrfy_pgset_get --
 *      Get the value associated in a page set with a given pgno.  Return
 *      a 0 value (and succeed) if we've never heard of this page.
 *
 * PUBLIC: int __db_vrfy_pgset_get __P((DB *, db_pgno_t, int *));
 */
int
__db_vrfy_pgset_get(dbp, pgno, valp)
        DB *dbp;
        db_pgno_t pgno;
        int *valp;
{
        DBT key, data;
        int ret, val;

        memset(&key, 0, sizeof(DBT));
        memset(&data, 0, sizeof(DBT));

        key.data = &pgno;
        key.size = sizeof(db_pgno_t);
        data.data = &val;
        data.ulen = sizeof(int);
        F_SET(&data, DB_DBT_USERMEM);

        if ((ret = __db_get(dbp, NULL, &key, &data, 0)) == 0) {
                DB_ASSERT(data.size == sizeof(int));
        } else if (ret == DB_NOTFOUND)
                val = 0;
        else
                return (ret);

        *valp = val;
        return (0);
}

/*
 * __db_vrfy_pgset_inc --
 *      Increment the value associated with a pgno by 1.
 *
 * PUBLIC: int __db_vrfy_pgset_inc __P((DB *, db_pgno_t));
 */
int
__db_vrfy_pgset_inc(dbp, pgno)
        DB *dbp;
        db_pgno_t pgno;
{
        DBT key, data;
        int ret;
        int val;

        memset(&key, 0, sizeof(DBT));
        memset(&data, 0, sizeof(DBT));

        val = 0;

        key.data = &pgno;
        key.size = sizeof(db_pgno_t);
        data.data = &val;
        data.ulen = sizeof(int);
        F_SET(&data, DB_DBT_USERMEM);

        if ((ret = __db_get(dbp, NULL, &key, &data, 0)) == 0) {
                DB_ASSERT(data.size == sizeof(int));
        } else if (ret != DB_NOTFOUND)
                return (ret);

        data.size = sizeof(int);
        ++val;

        return (__db_put(dbp, NULL, &key, &data, 0));
}

/*
 * __db_vrfy_pgset_next --
 *      Given a cursor open in a pgset database, get the next page in the
 *      set.
 *
 * PUBLIC: int __db_vrfy_pgset_next __P((DBC *, db_pgno_t *));
 */
int
__db_vrfy_pgset_next(dbc, pgnop)
        DBC *dbc;
        db_pgno_t *pgnop;
{
        DBT key, data;
        db_pgno_t pgno;
        int ret;

        memset(&key, 0, sizeof(DBT));
        memset(&data, 0, sizeof(DBT));
        /* We don't care about the data, just the keys. */
        F_SET(&data, DB_DBT_USERMEM | DB_DBT_PARTIAL);
        F_SET(&key, DB_DBT_USERMEM);
        key.data = &pgno;
        key.ulen = sizeof(db_pgno_t);

        if ((ret = __db_c_get(dbc, &key, &data, DB_NEXT)) != 0)
                return (ret);

        DB_ASSERT(key.size == sizeof(db_pgno_t));
        *pgnop = pgno;

        return (0);
}

/*
 * __db_vrfy_childcursor --
 *      Create a cursor to walk the child list with.  Returns with a nonzero
 *      final argument if the specified page has no children.
 *
 * PUBLIC: int __db_vrfy_childcursor __P((VRFY_DBINFO *, DBC **));
 */
int
__db_vrfy_childcursor(vdp, dbcp)
        VRFY_DBINFO *vdp;
        DBC **dbcp;
{
        DB *cdbp;
        DBC *dbc;
        int ret;

        cdbp = vdp->cdbp;

        if ((ret = __db_cursor(cdbp, NULL, &dbc, 0)) == 0)
                *dbcp = dbc;

        return (ret);
}

/*
 * __db_vrfy_childput --
 *      Add a child structure to the set for a given page.
 *
 * PUBLIC: int __db_vrfy_childput
 * PUBLIC:     __P((VRFY_DBINFO *, db_pgno_t, VRFY_CHILDINFO *));
 */
int
__db_vrfy_childput(vdp, pgno, cip)
        VRFY_DBINFO *vdp;
        db_pgno_t pgno;
        VRFY_CHILDINFO *cip;
{
        DB *cdbp;
        DBC *cc;
        DBT key, data;
        VRFY_CHILDINFO *oldcip;
        int ret;

        cdbp = vdp->cdbp;
        memset(&key, 0, sizeof(DBT));
        memset(&data, 0, sizeof(DBT));

        key.data = &pgno;
        key.size = sizeof(db_pgno_t);

        /*
         * We want to avoid adding multiple entries for a single child page;
         * we only need to verify each child once, even if a child (such
         * as an overflow key) is multiply referenced.
         *
         * However, we also need to make sure that when walking the list
         * of children, we encounter them in the order they're referenced
         * on a page.  (This permits us, for example, to verify the
         * prev_pgno/next_pgno chain of Btree leaf pages.)
         *
         * Check the child database to make sure that this page isn't
         * already a child of the specified page number.  If it's not,
         * put it at the end of the duplicate set.
         */
        if ((ret = __db_vrfy_childcursor(vdp, &cc)) != 0)
                return (ret);
        for (ret = __db_vrfy_ccset(cc, pgno, &oldcip); ret == 0;
            ret = __db_vrfy_ccnext(cc, &oldcip))
                if (oldcip->pgno == cip->pgno) {
                        /*
                         * Found a matching child.  Increment its reference
                         * count--we've run into it again--but don't put it
                         * again.
                         */
                        if ((ret = __db_vrfy_childinc(cc, oldcip)) != 0 ||
                            (ret = __db_vrfy_ccclose(cc)) != 0)
                                return (ret);
                        return (0);
                }
        if (ret != DB_NOTFOUND) {
                (void)__db_vrfy_ccclose(cc);
                return (ret);
        }
        if ((ret = __db_vrfy_ccclose(cc)) != 0)
                return (ret);

        cip->refcnt = 1;
        data.data = cip;
        data.size = sizeof(VRFY_CHILDINFO);

        return (__db_put(cdbp, NULL, &key, &data, 0));
}

/*
 * __db_vrfy_childinc --
 *      Increment the refcount of the VRFY_CHILDINFO struct that the child
 * cursor is pointing to.  (The caller has just retrieved this struct, and
 * passes it in as cip to save us a get.)
 */
static int
__db_vrfy_childinc(dbc, cip)
        DBC *dbc;
        VRFY_CHILDINFO *cip;
{
        DBT key, data;

        memset(&key, 0, sizeof(DBT));
        memset(&data, 0, sizeof(DBT));

        cip->refcnt++;
        data.data = cip;
        data.size = sizeof(VRFY_CHILDINFO);

        return (__db_c_put(dbc, &key, &data, DB_CURRENT));
}

/*
 * __db_vrfy_ccset --
 *      Sets a cursor created with __db_vrfy_childcursor to the first
 *      child of the given pgno, and returns it in the third arg.
 *
 * PUBLIC: int __db_vrfy_ccset __P((DBC *, db_pgno_t, VRFY_CHILDINFO **));
 */
int
__db_vrfy_ccset(dbc, pgno, cipp)
        DBC *dbc;
        db_pgno_t pgno;
        VRFY_CHILDINFO **cipp;
{
        DBT key, data;
        int ret;

        memset(&key, 0, sizeof(DBT));
        memset(&data, 0, sizeof(DBT));

        key.data = &pgno;
        key.size = sizeof(db_pgno_t);

        if ((ret = __db_c_get(dbc, &key, &data, DB_SET)) != 0)
                return (ret);

        DB_ASSERT(data.size == sizeof(VRFY_CHILDINFO));
        *cipp = (VRFY_CHILDINFO *)data.data;

        return (0);
}

/*
 * __db_vrfy_ccnext --
 *      Gets the next child of the given cursor created with
 *      __db_vrfy_childcursor, and returns it in the memory provided in the
 *      second arg.
 *
 * PUBLIC: int __db_vrfy_ccnext __P((DBC *, VRFY_CHILDINFO **));
 */
int
__db_vrfy_ccnext(dbc, cipp)
        DBC *dbc;
        VRFY_CHILDINFO **cipp;
{
        DBT key, data;
        int ret;

        memset(&key, 0, sizeof(DBT));
        memset(&data, 0, sizeof(DBT));

        if ((ret = __db_c_get(dbc, &key, &data, DB_NEXT_DUP)) != 0)
                return (ret);

        DB_ASSERT(data.size == sizeof(VRFY_CHILDINFO));
        *cipp = (VRFY_CHILDINFO *)data.data;

        return (0);
}

/*
 * __db_vrfy_ccclose --
 *      Closes the cursor created with __db_vrfy_childcursor.
 *
 *      This doesn't actually do anything interesting now, but it's
 *      not inconceivable that we might change the internal database usage
 *      and keep the interfaces the same, and a function call here or there
 *      seldom hurts anyone.
 *
 * PUBLIC: int __db_vrfy_ccclose __P((DBC *));
 */
int
__db_vrfy_ccclose(dbc)
        DBC *dbc;
{

        return (__db_c_close(dbc));
}

/*
 * __db_vrfy_pageinfo_create --
 *      Constructor for VRFY_PAGEINFO;  allocates and initializes.
 */
static int
__db_vrfy_pageinfo_create(dbenv, pipp)
        DB_ENV *dbenv;
        VRFY_PAGEINFO **pipp;
{
        VRFY_PAGEINFO *pip;
        int ret;

        /*
         * pageinfo structs are sometimes allocated here and sometimes
         * allocated by fetching them from a database with DB_DBT_MALLOC.
         * There's no easy way for the destructor to tell which was
         * used, and so we always allocate with __os_umalloc so we can free
         * with __os_ufree.
         */
        if ((ret = __os_umalloc(dbenv, sizeof(VRFY_PAGEINFO), &pip)) != 0)
                return (ret);
        memset(pip, 0, sizeof(VRFY_PAGEINFO));

        *pipp = pip;
        return (0);
}

/*
 * __db_salvage_init --
 *      Set up salvager database.
 *
 * PUBLIC: int  __db_salvage_init __P((VRFY_DBINFO *));
 */
int
__db_salvage_init(vdp)
        VRFY_DBINFO *vdp;
{
        DB *dbp;
        int ret;

        if ((ret = db_create(&dbp, NULL, 0)) != 0)
                return (ret);

        if ((ret = __db_set_pagesize(dbp, 1024)) != 0)
                goto err;

        if ((ret = __db_open(dbp,
            NULL, NULL, NULL, DB_BTREE, DB_CREATE, 0, PGNO_BASE_MD)) != 0)
                goto err;

        vdp->salvage_pages = dbp;
        return (0);

err:    (void)__db_close(dbp, NULL, 0);
        return (ret);
}

/*
 * __db_salvage_destroy --
 *      Close salvager database.
 * PUBLIC: void  __db_salvage_destroy __P((VRFY_DBINFO *));
 */
void
__db_salvage_destroy(vdp)
        VRFY_DBINFO *vdp;
{
        (void)__db_close(vdp->salvage_pages, NULL, 0);
}

/*
 * __db_salvage_getnext --
 *      Get the next (first) unprinted page in the database of pages we need to
 *      print still.  Delete entries for any already-printed pages we encounter
 *      in this search, as well as the page we're returning.
 *
 * PUBLIC: int __db_salvage_getnext
 * PUBLIC:     __P((VRFY_DBINFO *, DBC **, db_pgno_t *, u_int32_t *, int));
 */
int
__db_salvage_getnext(vdp, dbcp, pgnop, pgtypep, skip_overflow)
        VRFY_DBINFO *vdp;
        DBC **dbcp;
        db_pgno_t *pgnop;
        u_int32_t *pgtypep;
        int skip_overflow;
{
        DB *dbp;
        DBT key, data;
        int ret;
        u_int32_t pgtype;

        dbp = vdp->salvage_pages;

        memset(&key, 0, sizeof(DBT));
        memset(&data, 0, sizeof(DBT));

        if (*dbcp == NULL &&
            (ret = __db_cursor(dbp, NULL, dbcp, 0)) != 0)
                return (ret);

        while ((ret = __db_c_get(*dbcp, &key, &data, DB_NEXT)) == 0) {
                DB_ASSERT(data.size == sizeof(u_int32_t));
                memcpy(&pgtype, data.data, sizeof(pgtype));

                if (skip_overflow && pgtype == SALVAGE_OVERFLOW)
                        continue;

                if ((ret = __db_c_del(*dbcp, 0)) != 0)
                        return (ret);
                if (pgtype != SALVAGE_IGNORE) {
                        DB_ASSERT(key.size == sizeof(db_pgno_t));
                        DB_ASSERT(data.size == sizeof(u_int32_t));

                        *pgnop = *(db_pgno_t *)key.data;
                        *pgtypep = *(u_int32_t *)data.data;
                        break;
                }
        }

        return (ret);
}

/*
 * __db_salvage_isdone --
 *      Return whether or not the given pgno is already marked
 *      SALVAGE_IGNORE (meaning that we don't need to print it again).
 *
 *      Returns DB_KEYEXIST if it is marked, 0 if not, or another error on
 *      error.
 *
 * PUBLIC: int __db_salvage_isdone __P((VRFY_DBINFO *, db_pgno_t));
 */
int
__db_salvage_isdone(vdp, pgno)
        VRFY_DBINFO *vdp;
        db_pgno_t pgno;
{
        DBT key, data;
        DB *dbp;
        int ret;
        u_int32_t currtype;

        dbp = vdp->salvage_pages;

        memset(&key, 0, sizeof(DBT));
        memset(&data, 0, sizeof(DBT));

        currtype = SALVAGE_INVALID;
        data.data = &currtype;
        data.ulen = sizeof(u_int32_t);
        data.flags = DB_DBT_USERMEM;

        key.data = &pgno;
        key.size = sizeof(db_pgno_t);

        /*
         * Put an entry for this page, with pgno as key and type as data,
         * unless it's already there and is marked done.
         * If it's there and is marked anything else, that's fine--we
         * want to mark it done.
         */
        if ((ret = __db_get(dbp, NULL, &key, &data, 0)) == 0) {
                /*
                 * The key's already here.  Check and see if it's already
                 * marked done.  If it is, return DB_KEYEXIST.  If it's not,
                 * return 0.
                 */
                if (currtype == SALVAGE_IGNORE)
                        return (DB_KEYEXIST);
                else
                        return (0);
        } else if (ret != DB_NOTFOUND)
                return (ret);

        /* The pgno is not yet marked anything; return 0. */
        return (0);
}

/*
 * __db_salvage_markdone --
 *      Mark as done a given page.
 *
 * PUBLIC: int __db_salvage_markdone __P((VRFY_DBINFO *, db_pgno_t));
 */
int
__db_salvage_markdone(vdp, pgno)
        VRFY_DBINFO *vdp;
        db_pgno_t pgno;
{
        DBT key, data;
        DB *dbp;
        int pgtype, ret;
        u_int32_t currtype;

        pgtype = SALVAGE_IGNORE;
        dbp = vdp->salvage_pages;

        memset(&key, 0, sizeof(DBT));
        memset(&data, 0, sizeof(DBT));

        currtype = SALVAGE_INVALID;
        data.data = &currtype;
        data.ulen = sizeof(u_int32_t);
        data.flags = DB_DBT_USERMEM;

        key.data = &pgno;
        key.size = sizeof(db_pgno_t);

        /*
         * Put an entry for this page, with pgno as key and type as data,
         * unless it's already there and is marked done.
         * If it's there and is marked anything else, that's fine--we
         * want to mark it done, but db_salvage_isdone only lets
         * us know if it's marked IGNORE.
         *
         * We don't want to return DB_KEYEXIST, though;  this will
         * likely get passed up all the way and make no sense to the
         * application.  Instead, use DB_VERIFY_BAD to indicate that
         * we've seen this page already--it probably indicates a
         * multiply-linked page.
         */
        if ((ret = __db_salvage_isdone(vdp, pgno)) != 0)
                return (ret == DB_KEYEXIST ? DB_VERIFY_BAD : ret);

        data.size = sizeof(u_int32_t);
        data.data = &pgtype;

        return (__db_put(dbp, NULL, &key, &data, 0));
}

/*
 * __db_salvage_markneeded --
 *      If it has not yet been printed, make note of the fact that a page
 *      must be dealt with later.
 *
 * PUBLIC: int __db_salvage_markneeded
 * PUBLIC:     __P((VRFY_DBINFO *, db_pgno_t, u_int32_t));
 */
int
__db_salvage_markneeded(vdp, pgno, pgtype)
        VRFY_DBINFO *vdp;
        db_pgno_t pgno;
        u_int32_t pgtype;
{
        DB *dbp;
        DBT key, data;
        int ret;

        dbp = vdp->salvage_pages;

        memset(&key, 0, sizeof(DBT));
        memset(&data, 0, sizeof(DBT));

        key.data = &pgno;
        key.size = sizeof(db_pgno_t);

        data.data = &pgtype;
        data.size = sizeof(u_int32_t);

        /*
         * Put an entry for this page, with pgno as key and type as data,
         * unless it's already there, in which case it's presumably
         * already been marked done.
         */
        ret = __db_put(dbp, NULL, &key, &data, DB_NOOVERWRITE);
        return (ret == DB_KEYEXIST ? 0 : ret);
}

/*
 * __db_vrfy_prdbt --
 *      Print out a DBT data element from a verification routine.
 *
 * PUBLIC: int __db_vrfy_prdbt __P((DBT *, int, const char *, void *,
 * PUBLIC:     int (*)(void *, const void *), int, VRFY_DBINFO *));
 */
int
__db_vrfy_prdbt(dbtp, checkprint, prefix, handle, callback, is_recno, vdp)
        DBT *dbtp;
        int checkprint;
        const char *prefix;
        void *handle;
        int (*callback) __P((void *, const void *));
        int is_recno;
        VRFY_DBINFO *vdp;
{
        if (vdp != NULL) {
                /*
                 * If vdp is non-NULL, we might be the first key in the
                 * "fake" subdatabase used for key/data pairs we can't
                 * associate with a known subdb.
                 *
                 * Check and clear the SALVAGE_PRINTHEADER flag;  if
                 * it was set, print a subdatabase header.
                 */
                if (F_ISSET(vdp, SALVAGE_PRINTHEADER)) {
                        (void)__db_prheader(
                            NULL, "__OTHER__", 0, 0, handle, callback, vdp, 0);
                        F_CLR(vdp, SALVAGE_PRINTHEADER);
                        F_SET(vdp, SALVAGE_PRINTFOOTER);
                }

                /*
                 * Even if the printable flag wasn't set by our immediate
                 * caller, it may be set on a salvage-wide basis.
                 */
                if (F_ISSET(vdp, SALVAGE_PRINTABLE))
                        checkprint = 1;
        }
        return (
            __db_prdbt(dbtp, checkprint, prefix, handle, callback, is_recno));
}

---