lib/dns/dyndb.c

	dyndb.c revision 0c27b3fe77ac1d5094ba3521e8142d9e7973133f
/*
 * Copyright (C) 2015, 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/.
 */


#include <config.h>

#if HAVE_DLFCN_H
#include <dlfcn.h>
#elif _WIN32
#include <windows.h>
#endif

#include <isc/buffer.h>
#include <isc/mem.h>
#include <isc/mutex.h>
#include <isc/once.h>
#include <isc/result.h>
#include <isc/region.h>
#include <isc/task.h>
#include <isc/types.h>
#include <isc/util.h>

#include <dns/dyndb.h>
#include <dns/log.h>
#include <dns/types.h>
#include <dns/view.h>
#include <dns/zone.h>

#include <string.h>

#define CHECK(op)                       \
    do { result = (op);                 \
        if (result != ISC_R_SUCCESS) goto cleanup;  \
    } while (0)


typedef struct dyndb_implementation dyndb_implementation_t;
struct dyndb_implementation {
    isc_mem_t           *mctx;
    void                *handle;
    dns_dyndb_register_t        *register_func;
    dns_dyndb_destroy_t     *destroy_func;
    char                *name;
    void                *inst;
    LINK(dyndb_implementation_t)    link;
};

/*
 * List of dyndb implementations. Locked by dyndb_lock.
 *
 * These are stored here so they can be cleaned up on shutdown.
 * (The order in which they are stored is not important.)
 */
static LIST(dyndb_implementation_t) dyndb_implementations;

/* Locks dyndb_implementations. */
static isc_mutex_t dyndb_lock;
static isc_once_t once = ISC_ONCE_INIT;

static void
dyndb_initialize(void) {
    RUNTIME_CHECK(isc_mutex_init(&dyndb_lock) == ISC_R_SUCCESS);
    INIT_LIST(dyndb_implementations);
}

static dyndb_implementation_t *
impfind(const char *name) {
    dyndb_implementation_t *imp;

    for (imp = ISC_LIST_HEAD(dyndb_implementations);
         imp != NULL;
         imp = ISC_LIST_NEXT(imp, link))
        if (strcasecmp(name, imp->name) == 0)
            return (imp);
    return (NULL);
}

#if HAVE_DLFCN_H
static isc_result_t
load_symbol(void *handle, const char *filename,
        const char *symbol_name, void **symbolp)
{
    const char *errmsg;
    void *symbol;

    REQUIRE(handle != NULL);
    REQUIRE(symbolp != NULL && *symbolp == NULL);

    symbol = dlsym(handle, symbol_name);
    if (symbol == NULL) {
        errmsg = dlerror();
        if (errmsg == NULL)
            errmsg = "returned function pointer is NULL";
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DYNDB, ISC_LOG_ERROR,
                  "failed to lookup symbol %s in "
                  "dyndb module '%s': %s",
                  symbol_name, filename, errmsg);
        return (ISC_R_FAILURE);
    }
    dlerror();

    *symbolp = symbol;

    return (ISC_R_SUCCESS);
}

static isc_result_t
load_library(isc_mem_t *mctx, const char *filename, const char *instname,
         dyndb_implementation_t **impp)
{
    isc_result_t result;
    void *handle = NULL;
    dyndb_implementation_t *imp = NULL;
    dns_dyndb_register_t *register_func = NULL;
    dns_dyndb_destroy_t *destroy_func = NULL;
    dns_dyndb_version_t *version_func = NULL;
    int version, flags;

    REQUIRE(impp != NULL && *impp == NULL);

    isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
              DNS_LOGMODULE_DYNDB, ISC_LOG_INFO,
              "loading DynDB instance '%s' driver '%s'",
              instname, filename);

    flags = RTLD_NOW|RTLD_LOCAL;
#ifdef RTLD_DEEPBIND
    flags |= RTLD_DEEPBIND;
#endif

    handle = dlopen(filename, flags);
    if (handle == NULL)
        CHECK(ISC_R_FAILURE);

    /* Clear dlerror */
    dlerror();

    CHECK(load_symbol(handle, filename, "dyndb_version",
              (void **)&version_func));

    version = version_func(NULL);
    if (version < (DNS_DYNDB_VERSION - DNS_DYNDB_AGE) ||
        version > DNS_DYNDB_VERSION)
    {
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DYNDB, ISC_LOG_ERROR,
                  "driver API version mismatch: %d/%d",
                  version, DNS_DYNDB_VERSION);
        CHECK(ISC_R_FAILURE);
    }

    CHECK(load_symbol(handle, filename, "dyndb_init",
              (void **)&register_func));
    CHECK(load_symbol(handle, filename, "dyndb_destroy",
              (void **)&destroy_func));

    imp = isc_mem_get(mctx, sizeof(dyndb_implementation_t));
    if (imp == NULL)
        CHECK(ISC_R_NOMEMORY);

    imp->mctx = NULL;
    isc_mem_attach(mctx, &imp->mctx);
    imp->handle = handle;
    imp->register_func = register_func;
    imp->destroy_func = destroy_func;
    imp->name = isc_mem_strdup(mctx, instname);
    if (imp->name == NULL)
        CHECK(ISC_R_NOMEMORY);

    imp->inst = NULL;
    INIT_LINK(imp, link);

    *impp = imp;
    imp = NULL;

cleanup:
    if (result != ISC_R_SUCCESS)
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DYNDB, ISC_LOG_ERROR,
                  "failed to dynamically load instance '%s' "
                  "driver '%s': %s (%s)", instname, filename,
                  dlerror(), isc_result_totext(result));
    if (imp != NULL)
        isc_mem_putanddetach(&imp->mctx, imp, sizeof(dyndb_implementation_t));
    if (result != ISC_R_SUCCESS && handle != NULL)
        dlclose(handle);

    return (result);
}

static void
unload_library(dyndb_implementation_t **impp) {
    dyndb_implementation_t *imp;

    REQUIRE(impp != NULL && *impp != NULL);

    imp = *impp;

    isc_mem_free(imp->mctx, imp->name);
    isc_mem_putanddetach(&imp->mctx, imp, sizeof(dyndb_implementation_t));

    *impp = NULL;
}
#elif _WIN32
static isc_result_t
load_symbol(HMODULE handle, const char *filename,
        const char *symbol_name, void **symbolp)
{
    void *symbol;

    REQUIRE(handle != NULL);
    REQUIRE(symbolp != NULL && *symbolp == NULL);

    symbol = GetProcAddress(handle, symbol_name);
    if (symbol == NULL) {
        int errstatus = GetLastError();
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DYNDB, ISC_LOG_ERROR,
                  "failed to lookup symbol %s in "
                  "dyndb module '%s': %d",
                  symbol_name, filename, errstatus);
        return (ISC_R_FAILURE);
    }

    *symbolp = symbol;

    return (ISC_R_SUCCESS);
}

static isc_result_t
load_library(isc_mem_t *mctx, const char *filename, const char *instname,
         dyndb_implementation_t **impp)
{
    isc_result_t result;
    HMODULE handle;
    dyndb_implementation_t *imp = NULL;
    dns_dyndb_register_t *register_func = NULL;
    dns_dyndb_destroy_t *destroy_func = NULL;
    dns_dyndb_version_t *version_func = NULL;
    int version;

    REQUIRE(impp != NULL && *impp == NULL);

    isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
              DNS_LOGMODULE_DYNDB, ISC_LOG_INFO,
              "loading DynDB instance '%s' driver '%s'",
              instname, filename);

    handle = LoadLibraryA(filename);
    if (handle == NULL)
        CHECK(ISC_R_FAILURE);

    CHECK(load_symbol(handle, filename, "dyndb_version",
              (void **)&version_func));

    version = version_func(NULL);
    if (version < (DNS_DYNDB_VERSION - DNS_DYNDB_AGE) ||
        version > DNS_DYNDB_VERSION)
    {
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DYNDB, ISC_LOG_ERROR,
                  "driver API version mismatch: %d/%d",
                  version, DNS_DYNDB_VERSION);
        CHECK(ISC_R_FAILURE);
    }

    CHECK(load_symbol(handle, filename, "dyndb_init",
              (void **)&register_func));
    CHECK(load_symbol(handle, filename, "dyndb_destroy",
              (void **)&destroy_func));

    imp = isc_mem_get(mctx, sizeof(dyndb_implementation_t));
    if (imp == NULL)
        CHECK(ISC_R_NOMEMORY);

    imp->mctx = NULL;
    isc_mem_attach(mctx, &imp->mctx);
    imp->handle = handle;
    imp->register_func = register_func;
    imp->destroy_func = destroy_func;
    imp->name = isc_mem_strdup(mctx, instname);
    if (imp->name == NULL)
        CHECK(ISC_R_NOMEMORY);

    imp->inst = NULL;
    INIT_LINK(imp, link);

    *impp = imp;
    imp = NULL;

cleanup:
    if (result != ISC_R_SUCCESS)
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DYNDB, ISC_LOG_ERROR,
                  "failed to dynamically load instance '%s' "
                  "driver '%s': %d (%s)", instname, filename,
                  GetLastError(), isc_result_totext(result));
    if (imp != NULL)
        isc_mem_putanddetach(&imp->mctx, imp, sizeof(dyndb_implementation_t));
    if (result != ISC_R_SUCCESS && handle != NULL)
        FreeLibrary(handle);

    return (result);
}

static void
unload_library(dyndb_implementation_t **impp) {
    dyndb_implementation_t *imp;

    REQUIRE(impp != NULL && *impp != NULL);

    imp = *impp;

    isc_mem_free(imp->mctx, imp->name);
    isc_mem_putanddetach(&imp->mctx, imp, sizeof(dyndb_implementation_t));

    *impp = NULL;
}
#else   /* HAVE_DLFCN_H || _WIN32 */
static isc_result_t
load_library(isc_mem_t *mctx, const char *filename, const char *instname,
         dyndb_implementation_t **impp)
{
    UNUSED(mctx);
    UNUSED(filename);
    UNUSED(instname);
    UNUSED(impp);

    isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_DYNDB,
              ISC_LOG_ERROR,
              "dynamic database support is not implemented");

    return (ISC_R_NOTIMPLEMENTED);
}

static void
unload_library(dyndb_implementation_t **impp)
{
    UNUSED(impp);
}
#endif  /* HAVE_DLFCN_H */

isc_result_t
dns_dyndb_load(const char *libname, const char *name, const char *parameters,
           isc_mem_t *mctx, const dns_dyndbctx_t *dctx)
{
    isc_result_t result;
    dyndb_implementation_t *implementation = NULL;

    REQUIRE(DNS_DYNDBCTX_VALID(dctx));
    REQUIRE(name != NULL);

    RUNTIME_CHECK(isc_once_do(&once, dyndb_initialize) == ISC_R_SUCCESS);

    LOCK(&dyndb_lock);

    /* duplicate instance names are not allowed */
    if (impfind(name) != NULL)
        CHECK(ISC_R_EXISTS);

    CHECK(load_library(mctx, libname, name, &implementation));
    CHECK(implementation->register_func(mctx, name, parameters, dctx,
                        &implementation->inst));

    APPEND(dyndb_implementations, implementation, link);
    result = ISC_R_SUCCESS;

cleanup:
    if (result != ISC_R_SUCCESS)
        if (implementation != NULL)
            unload_library(&implementation);

    UNLOCK(&dyndb_lock);
    return (result);
}

void
dns_dyndb_cleanup(isc_boolean_t exiting) {
    dyndb_implementation_t *elem;
    dyndb_implementation_t *prev;

    RUNTIME_CHECK(isc_once_do(&once, dyndb_initialize) == ISC_R_SUCCESS);

    LOCK(&dyndb_lock);
    elem = TAIL(dyndb_implementations);
    while (elem != NULL) {
        prev = PREV(elem, link);
        UNLINK(dyndb_implementations, elem, link);
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DYNDB, ISC_LOG_INFO,
                  "unloading DynDB instance '%s'", elem->name);
        elem->destroy_func(&elem->inst);
        ENSURE(elem->inst == NULL);
        unload_library(&elem);
        elem = prev;
    }
    UNLOCK(&dyndb_lock);

    if (exiting == ISC_TRUE)
        isc_mutex_destroy(&dyndb_lock);
}

isc_result_t
dns_dyndb_createctx(isc_mem_t *mctx, const void *hashinit, isc_log_t *lctx,
            dns_view_t *view, dns_zonemgr_t *zmgr, isc_task_t *task,
            isc_timermgr_t *tmgr, dns_dyndbctx_t **dctxp)
{
    dns_dyndbctx_t *dctx;

    REQUIRE(dctxp != NULL && *dctxp == NULL);

    dctx = isc_mem_get(mctx, sizeof(*dctx));
    if (dctx == NULL)
        return (ISC_R_NOMEMORY);

    memset(dctx, 0, sizeof(*dctx));
    if (view != NULL)
        dns_view_attach(view, &dctx->view);
    if (zmgr != NULL)
        dns_zonemgr_attach(zmgr, &dctx->zmgr);
    if (task != NULL)
        isc_task_attach(task, &dctx->task);
    dctx->timermgr = tmgr;
    dctx->hashinit = hashinit;
    dctx->lctx = lctx;
    dctx->refvar = &isc_bind9;

    isc_mem_attach(mctx, &dctx->mctx);
    dctx->magic = DNS_DYNDBCTX_MAGIC;

    *dctxp = dctx;

    return (ISC_R_SUCCESS);
}

void
dns_dyndb_destroyctx(dns_dyndbctx_t **dctxp) {
    dns_dyndbctx_t *dctx;

    REQUIRE(dctxp != NULL && DNS_DYNDBCTX_VALID(*dctxp));

    dctx = *dctxp;
    *dctxp = NULL;

    dctx->magic = 0;

    if (dctx->view != NULL)
        dns_view_detach(&dctx->view);
    if (dctx->zmgr != NULL)
        dns_zonemgr_detach(&dctx->zmgr);
    if (dctx->task != NULL)
        isc_task_detach(&dctx->task);
    dctx->timermgr = NULL;
    dctx->lctx = NULL;

    isc_mem_putanddetach(&dctx->mctx, dctx, sizeof(*dctx));
}