krb_dbm.c

早期freebsd实现

    for (try = 0; try < KERB_DB_MAX_RETRY; try++) {
	trans = kerb_start_read();

	if ((code = kerb_dbl_lock(KERB_DBL_SHARED)) != 0)
	    return -1;

	db = dbm_open(current_db_name, O_RDONLY, 0600);

	*more = 0;

#ifdef DEBUG
	if (kerb_debug & 2)
	    fprintf(stderr,
		    "%s: db_get_principal for %s %s max = %d",
		    progname, name, inst, max);
#endif

	wildp = !strcmp(name, "*");
	wildi = !strcmp(inst, "*");

	if (!wildi && !wildp) {	/* nothing's wild */
	    encode_princ_key(&key, name, inst);
	    contents = dbm_fetch(db, key);
	    if (contents.dptr == NULL) {
		found = 0;
		goto done;
	    }
	    decode_princ_contents(&contents, principal);
#ifdef DEBUG
	    if (kerb_debug & 1) {
		fprintf(stderr, "\t found %s %s p_n length %d t_n length %d\n",
			principal->name, principal->instance,
			strlen(principal->name),
			strlen(principal->instance));
	    }
#endif
	    found = 1;
	    goto done;
	}
	/* process wild cards by looping through entire database */

	for (key = dbm_firstkey(db); key.dptr != NULL;
	     key = dbm_next(db, key)) {
	    decode_princ_key(&key, testname, testinst);
	    if ((wildp || !strcmp(testname, name)) &&
		(wildi || !strcmp(testinst, inst))) { /* have a match */
		if (found >= max) {
		    *more = 1;
		    goto done;
		} else {
		    found++;
		    contents = dbm_fetch(db, key);
		    decode_princ_contents(&contents, principal);
#ifdef DEBUG
		    if (kerb_debug & 1) {
			fprintf(stderr,
				"\tfound %s %s p_n length %d t_n length %d\n",
				principal->name, principal->instance,
				strlen(principal->name),
				strlen(principal->instance));
		    }
#endif
		    principal++; /* point to next */
		}
	    }
	}

    done:
	kerb_dbl_unlock();	/* unlock read lock */
	dbm_close(db);
	if (kerb_end_read(trans) == 0)
	    break;
	found = -1;
	if (!non_blocking)
	    sleep(1);
    }
    return (found);
}

/*
 * Update a name in the data base.  Returns number of names
 * successfully updated.
 */

kerb_db_put_principal(principal, max)
    Principal *principal;
    unsigned int max;		/* number of principal structs to
				 * update */

{
    int     found = 0, code;
    u_long  i;
    extern int errorproc();
    datum   key, contents;
    DBM    *db;

    gettimeofday(&timestamp, NULL);

    if (!init)
	kerb_db_init();

    if ((code = kerb_dbl_lock(KERB_DBL_EXCLUSIVE)) != 0)
	return -1;

    db = dbm_open(current_db_name, O_RDWR, 0600);

#ifdef DEBUG
    if (kerb_debug & 2)
	fprintf(stderr, "%s: kerb_db_put_principal  max = %d",
	    progname, max);
#endif

    /* for each one, stuff temps, and do replace/append */
    for (i = 0; i < max; i++) {
	encode_princ_contents(&contents, principal);
	encode_princ_key(&key, principal->name, principal->instance);
	if (dbm_store(db, key, contents, DBM_REPLACE) == -1) {
		found = -1;
		perror("dbm_store");
		break;
	}
#ifdef DEBUG
	if (kerb_debug & 1) {
	    fprintf(stderr, "\n put %s %s\n",
		principal->name, principal->instance);
	}
#endif
	found++;
	principal++;		/* bump to next struct			   */
    }

    dbm_close(db);
    kerb_dbl_unlock();		/* unlock database */
    return (found);
}

static void
encode_princ_key(key, name, instance)
    datum  *key;
    char   *name, *instance;
{
    static char keystring[ANAME_SZ + INST_SZ];

    bzero(keystring, ANAME_SZ + INST_SZ);
    strncpy(keystring, name, ANAME_SZ);
    strncpy(&keystring[ANAME_SZ], instance, INST_SZ);
    key->dptr = keystring;
    key->dsize = ANAME_SZ + INST_SZ;
}

static void
decode_princ_key(key, name, instance)
    datum  *key;
    char   *name, *instance;
{
    strncpy(name, key->dptr, ANAME_SZ);
    strncpy(instance, key->dptr + ANAME_SZ, INST_SZ);
    name[ANAME_SZ - 1] = '\0';
    instance[INST_SZ - 1] = '\0';
}

static void
encode_princ_contents(contents, principal)
    datum  *contents;
    Principal *principal;
{
    contents->dsize = sizeof(*principal);
    contents->dptr = (char *) principal;
}

static void
decode_princ_contents(contents, principal)
    datum  *contents;
    Principal *principal;
{
    bcopy(contents->dptr, (char *) principal, sizeof(*principal));
}

kerb_db_get_stat(s)
    DB_stat *s;
{
    gettimeofday(&timestamp, NULL);


    s->cpu = 0;
    s->elapsed = 0;
    s->dio = 0;
    s->pfault = 0;
    s->t_stamp = timestamp.tv_sec;
    s->n_retrieve = 0;
    s->n_replace = 0;
    s->n_append = 0;
    s->n_get_stat = 0;
    s->n_put_stat = 0;
    /* update local copy too */
}

kerb_db_put_stat(s)
    DB_stat *s;
{
}

delta_stat(a, b, c)
    DB_stat *a, *b, *c;
{
    /* c = a - b then b = a for the next time */

    c->cpu = a->cpu - b->cpu;
    c->elapsed = a->elapsed - b->elapsed;
    c->dio = a->dio - b->dio;
    c->pfault = a->pfault - b->pfault;
    c->t_stamp = a->t_stamp - b->t_stamp;
    c->n_retrieve = a->n_retrieve - b->n_retrieve;
    c->n_replace = a->n_replace - b->n_replace;
    c->n_append = a->n_append - b->n_append;
    c->n_get_stat = a->n_get_stat - b->n_get_stat;
    c->n_put_stat = a->n_put_stat - b->n_put_stat;

    bcopy(a, b, sizeof(DB_stat));
    return;
}

/*
 * look up a dba in the data base returns number of dbas found , and
 * whether there were more than requested. 
 */

kerb_db_get_dba(dba_name, dba_inst, dba, max, more)
    char   *dba_name;		/* could have wild card */
    char   *dba_inst;		/* could have wild card */
    Dba    *dba;
    unsigned int max;		/* max number of name structs to return */
    int    *more;		/* where there more than 'max' tuples? */

{
    *more = 0;
    return (0);
}

kerb_db_iterate (func, arg)
    int (*func)();
    char *arg;			/* void *, really */
{
    datum key, contents;
    Principal *principal;
    int code;
    DBM *db;
    
    kerb_db_init();		/* initialize and open the database */
    if ((code = kerb_dbl_lock(KERB_DBL_SHARED)) != 0)
	return code;

    db = dbm_open(current_db_name, O_RDONLY, 0600);

    for (key = dbm_firstkey (db); key.dptr != NULL; key = dbm_next(db, key)) {
	contents = dbm_fetch (db, key);
	/* XXX may not be properly aligned */
	principal = (Principal *) contents.dptr;
	if ((code = (*func)(arg, principal)) != 0)
	    return code;
    }
    dbm_close(db);
    kerb_dbl_unlock();
    return 0;
}

static int dblfd = -1;
static int mylock = 0;
static int inited = 0;

static kerb_dbl_init()
{
    if (!inited) {
	char *filename = gen_dbsuffix (current_db_name, ".ok");
	if ((dblfd = open(filename, 0)) < 0) {
	    fprintf(stderr, "kerb_dbl_init: couldn't open %s\n", filename);
	    fflush(stderr);
	    perror("open");
	    exit(1);
	}
	free(filename);
	inited++;
    }
    return (0);
}

static void kerb_dbl_fini()
{
    close(dblfd);
    dblfd = -1;
    inited = 0;
    mylock = 0;
}

static int kerb_dbl_lock(mode)
    int     mode;
{
    int flock_mode;
    
    if (!inited)
	kerb_dbl_init();
    if (mylock) {		/* Detect lock call when lock already
				 * locked */
	fprintf(stderr, "Kerberos locking error (mylock)\n");
	fflush(stderr);
	exit(1);
    }
    switch (mode) {
    case KERB_DBL_EXCLUSIVE:
	flock_mode = LOCK_EX;
	break;
    case KERB_DBL_SHARED:
	flock_mode = LOCK_SH;
	break;
    default:
	fprintf(stderr, "invalid lock mode %d\n", mode);
	abort();
    }
    if (non_blocking)
	flock_mode |= LOCK_NB;
    
    if (flock(dblfd, flock_mode) < 0) 
	return errno;
    mylock++;
    return 0;
}

static void kerb_dbl_unlock()
{
    if (!mylock) {		/* lock already unlocked */
	fprintf(stderr, "Kerberos database lock not locked when unlocking.\n");
	fflush(stderr);
	exit(1);
    }
    if (flock(dblfd, LOCK_UN) < 0) {
	fprintf(stderr, "Kerberos database lock error. (unlocking)\n");
	fflush(stderr);
	perror("flock");
	exit(1);
    }
    mylock = 0;
}

int kerb_db_set_lockmode(mode)
    int mode;
{
    int old = non_blocking;
    non_blocking = mode;
    return old;
}