named/unix/dlz_dlopen_driver.c

	dlz_dlopen_driver.c revision 2732d4922c2e72a399204320791acfd2fd3d6c7c
/*
 * Copyright (C) 2011-2014, 2016  Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

/* $Id$ */

#include <config.h>

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <dlfcn.h>

#include <dns/log.h>
#include <dns/result.h>
#include <dns/dlz_dlopen.h>

#include <isc/mem.h>
#include <isc/print.h>
#include <isc/result.h>
#include <isc/util.h>

#include <named/globals.h>

#include <dlz/dlz_dlopen_driver.h>

#ifdef ISC_DLZ_DLOPEN
static dns_sdlzimplementation_t *dlz_dlopen = NULL;


typedef struct dlopen_data {
    isc_mem_t *mctx;
    char *dl_path;
    char *dlzname;
    void *dl_handle;
    void *dbdata;
    unsigned int flags;
    isc_mutex_t lock;
    int version;
    isc_boolean_t in_configure;

    dlz_dlopen_version_t *dlz_version;
    dlz_dlopen_create_t *dlz_create;
    dlz_dlopen_findzonedb_t *dlz_findzonedb;
    dlz_dlopen_lookup_t *dlz_lookup;
    dlz_dlopen_authority_t *dlz_authority;
    dlz_dlopen_allnodes_t *dlz_allnodes;
    dlz_dlopen_allowzonexfr_t *dlz_allowzonexfr;
    dlz_dlopen_newversion_t *dlz_newversion;
    dlz_dlopen_closeversion_t *dlz_closeversion;
    dlz_dlopen_configure_t *dlz_configure;
    dlz_dlopen_ssumatch_t *dlz_ssumatch;
    dlz_dlopen_addrdataset_t *dlz_addrdataset;
    dlz_dlopen_subrdataset_t *dlz_subrdataset;
    dlz_dlopen_delrdataset_t *dlz_delrdataset;
    dlz_dlopen_destroy_t *dlz_destroy;
} dlopen_data_t;

/* Modules can choose whether they are lock-safe or not. */
#define MAYBE_LOCK(cd) \
    do { \
        if ((cd->flags & DNS_SDLZFLAG_THREADSAFE) == 0 && \
            cd->in_configure == ISC_FALSE) \
            LOCK(&cd->lock); \
    } while (0)

#define MAYBE_UNLOCK(cd) \
    do { \
        if ((cd->flags & DNS_SDLZFLAG_THREADSAFE) == 0 && \
            cd->in_configure == ISC_FALSE) \
            UNLOCK(&cd->lock); \
    } while (0)

/*
 * Log a message at the given level.
 */
static void dlopen_log(int level, const char *fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);
    isc_log_vwrite(dns_lctx, DNS_LOGCATEGORY_DATABASE,
               DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(level),
               fmt, ap);
    va_end(ap);
}

/*
 * SDLZ methods
 */

static isc_result_t
dlopen_dlz_allnodes(const char *zone, void *driverarg, void *dbdata,
            dns_sdlzallnodes_t *allnodes)
{
    dlopen_data_t *cd = (dlopen_data_t *) dbdata;
    isc_result_t result;


    UNUSED(driverarg);

    if (cd->dlz_allnodes == NULL) {
        return (ISC_R_NOPERM);
    }

    MAYBE_LOCK(cd);
    result = cd->dlz_allnodes(zone, cd->dbdata, allnodes);
    MAYBE_UNLOCK(cd);
    return (result);
}


static isc_result_t
dlopen_dlz_allowzonexfr(void *driverarg, void *dbdata, const char *name,
            const char *client)
{
    dlopen_data_t *cd = (dlopen_data_t *) dbdata;
    isc_result_t result;

    UNUSED(driverarg);


    if (cd->dlz_allowzonexfr == NULL) {
        return (ISC_R_NOPERM);
    }

    MAYBE_LOCK(cd);
    result = cd->dlz_allowzonexfr(cd->dbdata, name, client);
    MAYBE_UNLOCK(cd);
    return (result);
}

static isc_result_t
dlopen_dlz_authority(const char *zone, void *driverarg, void *dbdata,
             dns_sdlzlookup_t *lookup)
{
    dlopen_data_t *cd = (dlopen_data_t *) dbdata;
    isc_result_t result;

    UNUSED(driverarg);

    if (cd->dlz_authority == NULL) {
        return (ISC_R_NOTIMPLEMENTED);
    }

    MAYBE_LOCK(cd);
    result = cd->dlz_authority(zone, cd->dbdata, lookup);
    MAYBE_UNLOCK(cd);
    return (result);
}

static isc_result_t
dlopen_dlz_findzonedb(void *driverarg, void *dbdata, const char *name,
              dns_clientinfomethods_t *methods,
              dns_clientinfo_t *clientinfo)
{
    dlopen_data_t *cd = (dlopen_data_t *) dbdata;
    isc_result_t result;

    UNUSED(driverarg);

    MAYBE_LOCK(cd);
    result = cd->dlz_findzonedb(cd->dbdata, name, methods, clientinfo);
    MAYBE_UNLOCK(cd);
    return (result);
}


static isc_result_t
dlopen_dlz_lookup(const char *zone, const char *name, void *driverarg,
          void *dbdata, dns_sdlzlookup_t *lookup,
          dns_clientinfomethods_t *methods,
          dns_clientinfo_t *clientinfo)
{
    dlopen_data_t *cd = (dlopen_data_t *) dbdata;
    isc_result_t result;

    UNUSED(driverarg);

    MAYBE_LOCK(cd);
    result = cd->dlz_lookup(zone, name, cd->dbdata, lookup,
                methods, clientinfo);
    MAYBE_UNLOCK(cd);
    return (result);
}

/*
 * Load a symbol from the library
 */
static void *
dl_load_symbol(dlopen_data_t *cd, const char *symbol, isc_boolean_t mandatory) {
    void *ptr = dlsym(cd->dl_handle, symbol);
    if (ptr == NULL && mandatory) {
        dlopen_log(ISC_LOG_ERROR,
               "dlz_dlopen: library '%s' is missing "
               "required symbol '%s'", cd->dl_path, symbol);
    }
    return (ptr);
}

/*
 * Called at startup for each dlopen zone in named.conf
 */
static isc_result_t
dlopen_dlz_create(const char *dlzname, unsigned int argc, char *argv[],
          void *driverarg, void **dbdata)
{
    dlopen_data_t *cd;
    isc_mem_t *mctx = NULL;
    isc_result_t result = ISC_R_FAILURE;
    int dlopen_flags = 0;

    UNUSED(driverarg);

    if (argc < 2) {
        dlopen_log(ISC_LOG_ERROR,
               "dlz_dlopen driver for '%s' needs a path to "
               "the shared library", dlzname);
        return (ISC_R_FAILURE);
    }

    result = isc_mem_create(0, 0, &mctx);
    if (result != ISC_R_SUCCESS)
        return (result);

    cd = isc_mem_get(mctx, sizeof(*cd));
    if (cd == NULL) {
        isc_mem_destroy(&mctx);
        return (ISC_R_NOMEMORY);
    }
    memset(cd, 0, sizeof(*cd));

    cd->mctx = mctx;

    cd->dl_path = isc_mem_strdup(cd->mctx, argv[1]);
    if (cd->dl_path == NULL) {
        result = ISC_R_NOMEMORY;
        goto failed;
    }

    cd->dlzname = isc_mem_strdup(cd->mctx, dlzname);
    if (cd->dlzname == NULL) {
        result = ISC_R_NOMEMORY;
        goto failed;
    }

    /* Initialize the lock */
    result = isc_mutex_init(&cd->lock);
    if (result != ISC_R_SUCCESS)
        goto failed;

    /* Open the library */
    dlopen_flags = RTLD_NOW|RTLD_GLOBAL;

#ifdef RTLD_DEEPBIND
    /*
     * If RTLD_DEEPBIND is available then use it. This can avoid
     * issues with a module using a different version of a system
     * library than one that bind9 uses. For example, bind9 may link
     * to MIT kerberos, but the module may use Heimdal. If we don't
     * use RTLD_DEEPBIND then we could end up with Heimdal functions
     * calling MIT functions, which leads to bizarre results (usually
     * a segfault).
     */
    dlopen_flags |= RTLD_DEEPBIND;
#endif

    cd->dl_handle = dlopen(cd->dl_path, dlopen_flags);
    if (cd->dl_handle == NULL) {
        dlopen_log(ISC_LOG_ERROR,
               "dlz_dlopen failed to open library '%s' - %s",
               cd->dl_path, dlerror());
        result = ISC_R_FAILURE;
        goto failed;
    }

    /* Find the symbols */
    cd->dlz_version = (dlz_dlopen_version_t *)
        dl_load_symbol(cd, "dlz_version", ISC_TRUE);
    cd->dlz_create = (dlz_dlopen_create_t *)
        dl_load_symbol(cd, "dlz_create", ISC_TRUE);
    cd->dlz_lookup = (dlz_dlopen_lookup_t *)
        dl_load_symbol(cd, "dlz_lookup", ISC_TRUE);
    cd->dlz_findzonedb = (dlz_dlopen_findzonedb_t *)
        dl_load_symbol(cd, "dlz_findzonedb", ISC_TRUE);

    if (cd->dlz_create == NULL ||
        cd->dlz_version == NULL ||
        cd->dlz_lookup == NULL ||
        cd->dlz_findzonedb == NULL)
    {
        /* We're missing a required symbol */
        result = ISC_R_FAILURE;
        goto failed;
    }

    cd->dlz_allowzonexfr = (dlz_dlopen_allowzonexfr_t *)
        dl_load_symbol(cd, "dlz_allowzonexfr", ISC_FALSE);
    cd->dlz_allnodes = (dlz_dlopen_allnodes_t *)
        dl_load_symbol(cd, "dlz_allnodes",
                   ISC_TF(cd->dlz_allowzonexfr != NULL));
    cd->dlz_authority = (dlz_dlopen_authority_t *)
        dl_load_symbol(cd, "dlz_authority", ISC_FALSE);
    cd->dlz_newversion = (dlz_dlopen_newversion_t *)
        dl_load_symbol(cd, "dlz_newversion", ISC_FALSE);
    cd->dlz_closeversion = (dlz_dlopen_closeversion_t *)
        dl_load_symbol(cd, "dlz_closeversion",
                   ISC_TF(cd->dlz_newversion != NULL));
    cd->dlz_configure = (dlz_dlopen_configure_t *)
        dl_load_symbol(cd, "dlz_configure", ISC_FALSE);
    cd->dlz_ssumatch = (dlz_dlopen_ssumatch_t *)
        dl_load_symbol(cd, "dlz_ssumatch", ISC_FALSE);
    cd->dlz_addrdataset = (dlz_dlopen_addrdataset_t *)
        dl_load_symbol(cd, "dlz_addrdataset", ISC_FALSE);
    cd->dlz_subrdataset = (dlz_dlopen_subrdataset_t *)
        dl_load_symbol(cd, "dlz_subrdataset", ISC_FALSE);
    cd->dlz_delrdataset = (dlz_dlopen_delrdataset_t *)
        dl_load_symbol(cd, "dlz_delrdataset", ISC_FALSE);
    cd->dlz_destroy = (dlz_dlopen_destroy_t *)
        dl_load_symbol(cd, "dlz_destroy", ISC_FALSE);

    /* Check the version of the API is the same */
    cd->version = cd->dlz_version(&cd->flags);
    if (cd->version < (DLZ_DLOPEN_VERSION - DLZ_DLOPEN_AGE) ||
        cd->version > DLZ_DLOPEN_VERSION)
    {
        dlopen_log(ISC_LOG_ERROR,
               "dlz_dlopen: %s: incorrect driver API version %d, "
               "requires %d",
               cd->dl_path, cd->version, DLZ_DLOPEN_VERSION);
        result = ISC_R_FAILURE;
        goto failed;
    }

    /*
     * Call the library's create function. Note that this is an
     * extended version of dlz create, with the addition of
     * named function pointers for helper functions that the
     * driver will need. This avoids the need for the backend to
     * link the BIND9 libraries
     */
    MAYBE_LOCK(cd);
    result = cd->dlz_create(dlzname, argc-1, argv+1,
                &cd->dbdata,
                "log", dlopen_log,
                "putrr", dns_sdlz_putrr,
                "putnamedrr", dns_sdlz_putnamedrr,
                "writeable_zone", dns_dlz_writeablezone,
                NULL);
    MAYBE_UNLOCK(cd);
    if (result != ISC_R_SUCCESS)
        goto failed;

    *dbdata = cd;

    return (ISC_R_SUCCESS);

failed:
    dlopen_log(ISC_LOG_ERROR, "dlz_dlopen of '%s' failed", dlzname);
    if (cd->dl_path != NULL)
        isc_mem_free(mctx, cd->dl_path);
    if (cd->dlzname != NULL)
        isc_mem_free(mctx, cd->dlzname);
    if (dlopen_flags != 0)
        (void) isc_mutex_destroy(&cd->lock);
#ifdef HAVE_DLCLOSE
    if (cd->dl_handle)
        dlclose(cd->dl_handle);
#endif
    isc_mem_put(mctx, cd, sizeof(*cd));
    isc_mem_destroy(&mctx);
    return (result);
}

/*
 * Called when bind is shutting down
 */
static void
dlopen_dlz_destroy(void *driverarg, void *dbdata) {
    dlopen_data_t *cd = (dlopen_data_t *) dbdata;
    isc_mem_t *mctx;

    UNUSED(driverarg);

    if (cd->dlz_destroy) {
        MAYBE_LOCK(cd);
        cd->dlz_destroy(cd->dbdata);
        MAYBE_UNLOCK(cd);
    }

    if (cd->dl_path)
        isc_mem_free(cd->mctx, cd->dl_path);
    if (cd->dlzname)
        isc_mem_free(cd->mctx, cd->dlzname);

#ifdef HAVE_DLCLOSE
    if (cd->dl_handle)
        dlclose(cd->dl_handle);
#endif

    (void) isc_mutex_destroy(&cd->lock);

    mctx = cd->mctx;
    isc_mem_put(mctx, cd, sizeof(*cd));
    isc_mem_destroy(&mctx);
}

/*
 * Called to start a transaction
 */
static isc_result_t
dlopen_dlz_newversion(const char *zone, void *driverarg, void *dbdata,
              void **versionp)
{
    dlopen_data_t *cd = (dlopen_data_t *) dbdata;
    isc_result_t result;

    UNUSED(driverarg);

    if (cd->dlz_newversion == NULL)
        return (ISC_R_NOTIMPLEMENTED);

    MAYBE_LOCK(cd);
    result = cd->dlz_newversion(zone, cd->dbdata, versionp);
    MAYBE_UNLOCK(cd);
    return (result);
}

/*
 * Called to end a transaction
 */
static void
dlopen_dlz_closeversion(const char *zone, isc_boolean_t commit,
            void *driverarg, void *dbdata, void **versionp)
{
    dlopen_data_t *cd = (dlopen_data_t *) dbdata;

    UNUSED(driverarg);

    if (cd->dlz_newversion == NULL) {
        *versionp = NULL;
        return;
    }

    MAYBE_LOCK(cd);
    cd->dlz_closeversion(zone, commit, cd->dbdata, versionp);
    MAYBE_UNLOCK(cd);
}

/*
 * Called on startup to configure any writeable zones
 */
static isc_result_t
dlopen_dlz_configure(dns_view_t *view, dns_dlzdb_t *dlzdb,
             void *driverarg, void *dbdata)
{
    dlopen_data_t *cd = (dlopen_data_t *) dbdata;
    isc_result_t result;

    UNUSED(driverarg);

    if (cd->dlz_configure == NULL)
        return (ISC_R_SUCCESS);

    MAYBE_LOCK(cd);
    cd->in_configure = ISC_TRUE;
    result = cd->dlz_configure(view, dlzdb, cd->dbdata);
    cd->in_configure = ISC_FALSE;
    MAYBE_UNLOCK(cd);

    return (result);
}


/*
 * Check for authority to change a name.
 */
static isc_boolean_t
dlopen_dlz_ssumatch(const char *signer, const char *name, const char *tcpaddr,
            const char *type, const char *key, isc_uint32_t keydatalen,
            unsigned char *keydata, void *driverarg, void *dbdata)
{
    dlopen_data_t *cd = (dlopen_data_t *) dbdata;
    isc_boolean_t ret;

    UNUSED(driverarg);

    if (cd->dlz_ssumatch == NULL)
        return (ISC_FALSE);

    MAYBE_LOCK(cd);
    ret = cd->dlz_ssumatch(signer, name, tcpaddr, type, key, keydatalen,
                   keydata, cd->dbdata);
    MAYBE_UNLOCK(cd);

    return (ret);
}


/*
 * Add an rdataset.
 */
static isc_result_t
dlopen_dlz_addrdataset(const char *name, const char *rdatastr,
               void *driverarg, void *dbdata, void *version)
{
    dlopen_data_t *cd = (dlopen_data_t *) dbdata;
    isc_result_t result;

    UNUSED(driverarg);

    if (cd->dlz_addrdataset == NULL)
        return (ISC_R_NOTIMPLEMENTED);

    MAYBE_LOCK(cd);
    result = cd->dlz_addrdataset(name, rdatastr, cd->dbdata, version);
    MAYBE_UNLOCK(cd);

    return (result);
}

/*
 * Subtract an rdataset.
 */
static isc_result_t
dlopen_dlz_subrdataset(const char *name, const char *rdatastr,
               void *driverarg, void *dbdata, void *version)
{
    dlopen_data_t *cd = (dlopen_data_t *) dbdata;
    isc_result_t result;

    UNUSED(driverarg);

    if (cd->dlz_subrdataset == NULL)
        return (ISC_R_NOTIMPLEMENTED);

    MAYBE_LOCK(cd);
    result = cd->dlz_subrdataset(name, rdatastr, cd->dbdata, version);
    MAYBE_UNLOCK(cd);

    return (result);
}

/*
 * Delete a rdataset.
 */
static isc_result_t
dlopen_dlz_delrdataset(const char *name, const char *type,
               void *driverarg, void *dbdata, void *version)
{
    dlopen_data_t *cd = (dlopen_data_t *) dbdata;
    isc_result_t result;

    UNUSED(driverarg);

    if (cd->dlz_delrdataset == NULL)
        return (ISC_R_NOTIMPLEMENTED);

    MAYBE_LOCK(cd);
    result = cd->dlz_delrdataset(name, type, cd->dbdata, version);
    MAYBE_UNLOCK(cd);

    return (result);
}


static dns_sdlzmethods_t dlz_dlopen_methods = {
    dlopen_dlz_create,
    dlopen_dlz_destroy,
    dlopen_dlz_findzonedb,
    dlopen_dlz_lookup,
    dlopen_dlz_authority,
    dlopen_dlz_allnodes,
    dlopen_dlz_allowzonexfr,
    dlopen_dlz_newversion,
    dlopen_dlz_closeversion,
    dlopen_dlz_configure,
    dlopen_dlz_ssumatch,
    dlopen_dlz_addrdataset,
    dlopen_dlz_subrdataset,
    dlopen_dlz_delrdataset
};
#endif

/*
 * Register driver with BIND
 */
isc_result_t
dlz_dlopen_init(isc_mem_t *mctx) {
#ifndef ISC_DLZ_DLOPEN
    UNUSED(mctx);
    return (ISC_R_NOTIMPLEMENTED);
#else
    isc_result_t result;

    dlopen_log(2, "Registering DLZ_dlopen driver");

    result = dns_sdlzregister("dlopen", &dlz_dlopen_methods, NULL,
                  DNS_SDLZFLAG_RELATIVEOWNER |
                  DNS_SDLZFLAG_RELATIVERDATA |
                  DNS_SDLZFLAG_THREADSAFE,
                  mctx, &dlz_dlopen);

    if (result != ISC_R_SUCCESS) {
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 "dns_sdlzregister() failed: %s",
                 isc_result_totext(result));
        result = ISC_R_UNEXPECTED;
    }

    return (result);
#endif
}


/*
 * Unregister the driver
 */
void
dlz_dlopen_clear(void) {
#ifdef ISC_DLZ_DLOPEN
    dlopen_log(2, "Unregistering DLZ_dlopen driver");
    if (dlz_dlopen != NULL)
        dns_sdlzunregister(&dlz_dlopen);
#endif
}