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-rw-r--r--src/utils/knotd/main.c635
1 files changed, 635 insertions, 0 deletions
diff --git a/src/utils/knotd/main.c b/src/utils/knotd/main.c
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index 0000000..3499028
--- /dev/null
+++ b/src/utils/knotd/main.c
@@ -0,0 +1,635 @@
+/* Copyright (C) 2022 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <signal.h>
+#include <sys/stat.h>
+#include <urcu.h>
+
+#ifdef ENABLE_CAP_NG
+#include <cap-ng.h>
+#endif
+
+#include "libdnssec/crypto.h"
+#include "libknot/libknot.h"
+#include "contrib/strtonum.h"
+#include "knot/ctl/process.h"
+#include "knot/conf/conf.h"
+#include "knot/conf/migration.h"
+#include "knot/conf/module.h"
+#include "knot/common/log.h"
+#include "knot/common/process.h"
+#include "knot/common/stats.h"
+#include "knot/common/systemd.h"
+#include "knot/server/server.h"
+#include "knot/server/tcp-handler.h"
+
+#define PROGRAM_NAME "knotd"
+
+/* Signal flags. */
+static volatile bool sig_req_stop = false;
+static volatile bool sig_req_reload = false;
+static volatile bool sig_req_zones_reload = false;
+
+static int make_daemon(int nochdir, int noclose)
+{
+ int ret;
+
+ switch (fork()) {
+ case -1:
+ /* Error */
+ return -1;
+ case 0:
+ /* Forked */
+ break;
+ default:
+ /* Exit the main process */
+ _exit(0);
+ }
+
+ if (setsid() == -1) {
+ return -1;
+ }
+
+ if (!nochdir) {
+ ret = chdir("/");
+ if (ret == -1)
+ return errno;
+ }
+
+ if (!noclose) {
+ ret = close(STDIN_FILENO);
+ ret += close(STDOUT_FILENO);
+ ret += close(STDERR_FILENO);
+ if (ret < 0) {
+ return errno;
+ }
+
+ int fd = open("/dev/null", O_RDWR);
+ if (fd == -1) {
+ return errno;
+ }
+
+ if (dup2(fd, STDIN_FILENO) < 0) {
+ close(fd);
+ return errno;
+ }
+ if (dup2(fd, STDOUT_FILENO) < 0) {
+ close(fd);
+ return errno;
+ }
+ if (dup2(fd, STDERR_FILENO) < 0) {
+ close(fd);
+ return errno;
+ }
+ close(fd);
+ }
+
+ return 0;
+}
+
+struct signal {
+ int signum;
+ bool handle;
+};
+
+/*! \brief Signals used by the server. */
+static const struct signal SIGNALS[] = {
+ { SIGHUP, true }, /* Reload server. */
+ { SIGUSR1, true }, /* Reload zones. */
+ { SIGINT, true }, /* Terminate server. */
+ { SIGTERM, true }, /* Terminate server. */
+ { SIGALRM, false }, /* Internal thread synchronization. */
+ { SIGPIPE, false }, /* Ignored. Some I/O errors. */
+ { 0 }
+};
+
+/*! \brief Server signal handler. */
+static void handle_signal(int signum)
+{
+ switch (signum) {
+ case SIGHUP:
+ sig_req_reload = true;
+ break;
+ case SIGUSR1:
+ sig_req_zones_reload = true;
+ break;
+ case SIGINT:
+ case SIGTERM:
+ if (sig_req_stop) {
+ exit(EXIT_FAILURE);
+ }
+ sig_req_stop = true;
+ break;
+ default:
+ /* ignore */
+ break;
+ }
+}
+
+/*! \brief Setup signal handlers and blocking mask. */
+static void setup_signals(void)
+{
+ /* Block all signals. */
+ static sigset_t all;
+ sigfillset(&all);
+ sigdelset(&all, SIGPROF);
+ sigdelset(&all, SIGQUIT);
+ sigdelset(&all, SIGILL);
+ sigdelset(&all, SIGABRT);
+ sigdelset(&all, SIGBUS);
+ sigdelset(&all, SIGFPE);
+ sigdelset(&all, SIGSEGV);
+ pthread_sigmask(SIG_SETMASK, &all, NULL);
+
+ /* Setup handlers. */
+ struct sigaction action = { .sa_handler = handle_signal };
+ for (const struct signal *s = SIGNALS; s->signum > 0; s++) {
+ sigaction(s->signum, &action, NULL);
+ }
+}
+
+/*! \brief Unblock server control signals. */
+static void enable_signals(void)
+{
+ sigset_t mask;
+ sigemptyset(&mask);
+
+ for (const struct signal *s = SIGNALS; s->signum > 0; s++) {
+ if (s->handle) {
+ sigaddset(&mask, s->signum);
+ }
+ }
+
+ pthread_sigmask(SIG_UNBLOCK, &mask, NULL);
+}
+
+/*! \brief Drop POSIX 1003.1e capabilities. */
+static void drop_capabilities(void)
+{
+#ifdef ENABLE_CAP_NG
+ /* Drop all capabilities. */
+ if (capng_have_capability(CAPNG_EFFECTIVE, CAP_SETPCAP)) {
+ capng_clear(CAPNG_SELECT_BOTH);
+
+ /* Apply. */
+ if (capng_apply(CAPNG_SELECT_BOTH) < 0) {
+ log_error("failed to set process capabilities (%s)",
+ strerror(errno));
+ }
+ } else {
+ log_info("process not allowed to set capabilities, skipping");
+ }
+#endif /* ENABLE_CAP_NG */
+}
+
+/*! \brief Event loop listening for signals and remote commands. */
+static void event_loop(server_t *server, const char *socket)
+{
+ knot_ctl_t *ctl = knot_ctl_alloc();
+ if (ctl == NULL) {
+ log_fatal("control, failed to initialize (%s)",
+ knot_strerror(KNOT_ENOMEM));
+ return;
+ }
+
+ // Set control timeout.
+ knot_ctl_set_timeout(ctl, conf()->cache.ctl_timeout);
+
+ /* Get control socket configuration. */
+ char *listen;
+ if (socket == NULL) {
+ conf_val_t listen_val = conf_get(conf(), C_CTL, C_LISTEN);
+ conf_val_t rundir_val = conf_get(conf(), C_SRV, C_RUNDIR);
+ char *rundir = conf_abs_path(&rundir_val, NULL);
+ listen = conf_abs_path(&listen_val, rundir);
+ free(rundir);
+ } else {
+ listen = strdup(socket);
+ }
+ if (listen == NULL) {
+ knot_ctl_free(ctl);
+ log_fatal("control, empty socket path");
+ return;
+ }
+
+ log_info("control, binding to '%s'", listen);
+
+ /* Bind the control socket. */
+ int ret = knot_ctl_bind(ctl, listen);
+ if (ret != KNOT_EOK) {
+ knot_ctl_free(ctl);
+ log_fatal("control, failed to bind socket '%s' (%s)",
+ listen, knot_strerror(ret));
+ free(listen);
+ return;
+ }
+ free(listen);
+
+ enable_signals();
+
+ /* Notify systemd about successful start. */
+ systemd_ready_notify();
+ if (conf()->cache.srv_dbus_event & DBUS_EVENT_RUNNING) {
+ systemd_emit_running(true);
+ }
+
+ /* Run event loop. */
+ for (;;) {
+ /* Interrupts. */
+ if (sig_req_reload && !sig_req_stop) {
+ sig_req_reload = false;
+ server_reload(server, RELOAD_FULL);
+ }
+ if (sig_req_zones_reload && !sig_req_stop) {
+ sig_req_zones_reload = false;
+ reload_t mode = server->catalog_upd_signal ? RELOAD_CATALOG : RELOAD_ZONES;
+ server->catalog_upd_signal = false;
+ server_update_zones(conf(), server, mode);
+ }
+ if (sig_req_stop) {
+ break;
+ }
+
+ // Update control timeout.
+ knot_ctl_set_timeout(ctl, conf()->cache.ctl_timeout);
+
+ if (sig_req_reload || sig_req_zones_reload) {
+ continue;
+ }
+
+ ret = knot_ctl_accept(ctl);
+ if (ret != KNOT_EOK) {
+ continue;
+ }
+
+ ret = ctl_process(ctl, server);
+ knot_ctl_close(ctl);
+ if (ret == KNOT_CTL_ESTOP) {
+ break;
+ }
+ }
+
+ if (conf()->cache.srv_dbus_event & DBUS_EVENT_RUNNING) {
+ systemd_emit_running(false);
+ }
+
+ /* Unbind the control socket. */
+ knot_ctl_unbind(ctl);
+ knot_ctl_free(ctl);
+}
+
+static void print_help(void)
+{
+ printf("Usage: %s [parameters]\n"
+ "\n"
+ "Parameters:\n"
+ " -c, --config <file> Use a textual configuration file.\n"
+ " (default %s)\n"
+ " -C, --confdb <dir> Use a binary configuration database directory.\n"
+ " (default %s)\n"
+ " -m, --max-conf-size <MiB> Set maximum size of the configuration database (max 10000 MiB).\n"
+ " (default %d MiB)\n"
+ " -s, --socket <path> Use a remote control UNIX socket path.\n"
+ " (default %s)\n"
+ " -d, --daemonize=[dir] Run the server as a daemon (with new root directory).\n"
+ " -v, --verbose Enable debug output.\n"
+ " -h, --help Print the program help.\n"
+ " -V, --version Print the program version.\n",
+ PROGRAM_NAME, CONF_DEFAULT_FILE, CONF_DEFAULT_DBDIR,
+ CONF_MAPSIZE, RUN_DIR "/knot.sock");
+}
+
+static void print_version(void)
+{
+ printf("%s (Knot DNS), version %s\n", PROGRAM_NAME, PACKAGE_VERSION);
+}
+
+static int set_config(const char *confdb, const char *config, size_t max_conf_size)
+{
+ if (config != NULL && confdb != NULL) {
+ log_fatal("ambiguous configuration source");
+ return KNOT_EINVAL;
+ }
+
+ /* Choose the optimal config source. */
+ bool import = false;
+ if (confdb != NULL) {
+ import = false;
+ } else if (config != NULL){
+ import = true;
+ } else if (conf_db_exists(CONF_DEFAULT_DBDIR)) {
+ import = false;
+ confdb = CONF_DEFAULT_DBDIR;
+ } else {
+ import = true;
+ config = CONF_DEFAULT_FILE;
+ }
+
+ /* Open confdb. */
+ conf_t *new_conf = NULL;
+ int ret = conf_new(&new_conf, conf_schema, confdb, max_conf_size, CONF_FREQMODULES);
+ if (ret != KNOT_EOK) {
+ log_fatal("failed to open configuration database '%s' (%s)",
+ (confdb != NULL) ? confdb : "", knot_strerror(ret));
+ return ret;
+ }
+
+ /* Import the config file. */
+ if (import) {
+ ret = conf_import(new_conf, config, true, true);
+ if (ret != KNOT_EOK) {
+ log_fatal("failed to load configuration file '%s' (%s)",
+ config, knot_strerror(ret));
+ conf_free(new_conf);
+ return ret;
+ }
+ }
+
+ // Migrate from old schema.
+ ret = conf_migrate(new_conf);
+ if (ret != KNOT_EOK) {
+ log_error("failed to migrate configuration (%s)", knot_strerror(ret));
+ }
+
+ /* Update to the new config. */
+ conf_update(new_conf, CONF_UPD_FNONE);
+
+ return KNOT_EOK;
+}
+
+int main(int argc, char **argv)
+{
+ bool daemonize = false;
+ const char *config = NULL;
+ const char *confdb = NULL;
+ size_t max_conf_size = (size_t)CONF_MAPSIZE * 1024 * 1024;
+ const char *daemon_root = "/";
+ char *socket = NULL;
+ bool verbose = false;
+
+ /* Long options. */
+ struct option opts[] = {
+ { "config", required_argument, NULL, 'c' },
+ { "confdb", required_argument, NULL, 'C' },
+ { "max-conf-size", required_argument, NULL, 'm' },
+ { "socket", required_argument, NULL, 's' },
+ { "daemonize", optional_argument, NULL, 'd' },
+ { "verbose", no_argument, NULL, 'v' },
+ { "help", no_argument, NULL, 'h' },
+ { "version", no_argument, NULL, 'V' },
+ { NULL }
+ };
+
+ /* Set the time zone. */
+ tzset();
+
+ /* Parse command line arguments. */
+ int opt = 0;
+ while ((opt = getopt_long(argc, argv, "c:C:m:s:dvhV", opts, NULL)) != -1) {
+ switch (opt) {
+ case 'c':
+ config = optarg;
+ break;
+ case 'C':
+ confdb = optarg;
+ break;
+ case 'm':
+ if (str_to_size(optarg, &max_conf_size, 1, 10000) != KNOT_EOK) {
+ print_help();
+ return EXIT_FAILURE;
+ }
+ /* Convert to bytes. */
+ max_conf_size *= 1024 * 1024;
+ break;
+ case 's':
+ socket = optarg;
+ break;
+ case 'd':
+ daemonize = true;
+ if (optarg) {
+ daemon_root = optarg;
+ }
+ break;
+ case 'v':
+ verbose = true;
+ break;
+ case 'h':
+ print_help();
+ return EXIT_SUCCESS;
+ case 'V':
+ print_version();
+ return EXIT_SUCCESS;
+ default:
+ print_help();
+ return EXIT_FAILURE;
+ }
+ }
+
+ /* Check for non-option parameters. */
+ if (argc - optind > 0) {
+ print_help();
+ return EXIT_FAILURE;
+ }
+
+ /* Set file creation mask to remove all permissions for others. */
+ umask(S_IROTH|S_IWOTH|S_IXOTH);
+
+ /* Now check if we want to daemonize. */
+ if (daemonize) {
+ if (make_daemon(1, 0) != 0) {
+ fprintf(stderr, "Daemonization failed, shutting down...\n");
+ return EXIT_FAILURE;
+ }
+ }
+
+ /* Setup base signal handling. */
+ setup_signals();
+
+ /* Initialize cryptographic backend. */
+ dnssec_crypto_init();
+
+ /* Initialize pseudorandom number generator. */
+ srand(time(NULL));
+
+ /* Initialize logging subsystem. */
+ log_init();
+ if (verbose) {
+ log_levels_add(LOG_TARGET_STDOUT, LOG_SOURCE_ANY, LOG_MASK(LOG_DEBUG));
+ }
+
+ /* Set up the configuration */
+ int ret = set_config(confdb, config, max_conf_size);
+ if (ret != KNOT_EOK) {
+ log_close();
+ dnssec_crypto_cleanup();
+ return EXIT_FAILURE;
+ }
+
+ /* Reconfigure logging. */
+ log_reconfigure(conf());
+
+ /* Initialize server. */
+ server_t server;
+ ret = server_init(&server, conf()->cache.srv_bg_threads);
+ if (ret != KNOT_EOK) {
+ log_fatal("failed to initialize server (%s)", knot_strerror(ret));
+ conf_free(conf());
+ log_close();
+ dnssec_crypto_cleanup();
+ return EXIT_FAILURE;
+ }
+
+ /* Reconfigure server workers, interfaces, and databases.
+ * @note This MUST be done before we drop privileges. */
+ ret = server_reconfigure(conf(), &server);
+ if (ret != KNOT_EOK) {
+ log_fatal("failed to configure server");
+ server_wait(&server);
+ server_deinit(&server);
+ conf_free(conf());
+ log_close();
+ dnssec_crypto_cleanup();
+ return EXIT_FAILURE;
+ }
+
+ if (conf()->cache.srv_dbus_event != DBUS_EVENT_NONE) {
+ ret = systemd_dbus_open();
+ if (ret != KNOT_EOK) {
+ log_error("d-bus: failed to open system bus (%s)",
+ knot_strerror(ret));
+ } else {
+ log_info("d-bus: connected to system bus");
+ }
+ int64_t delay = conf_get_int(conf(), C_SRV, C_DBUS_INIT_DELAY);
+ sleep(delay);
+ }
+
+ /* Alter privileges. */
+ int uid, gid;
+ if (conf_user(conf(), &uid, &gid) != KNOT_EOK ||
+ log_update_privileges(uid, gid) != KNOT_EOK ||
+ proc_update_privileges(uid, gid) != KNOT_EOK) {
+ log_fatal("failed to drop privileges");
+ server_wait(&server);
+ server_deinit(&server);
+ conf_free(conf());
+ systemd_dbus_close();
+ log_close();
+ dnssec_crypto_cleanup();
+ return EXIT_FAILURE;
+ }
+
+ /* Drop POSIX capabilities. */
+ drop_capabilities();
+
+ /* Activate global query modules. */
+ conf_activate_modules(conf(), &server, NULL, conf()->query_modules,
+ &conf()->query_plan);
+
+ /* Check and create PID file. */
+ unsigned long pid = pid_check_and_create();
+ if (pid == 0) {
+ server_wait(&server);
+ server_deinit(&server);
+ conf_free(conf());
+ systemd_dbus_close();
+ log_close();
+ dnssec_crypto_cleanup();
+ return EXIT_FAILURE;
+ }
+
+ if (daemonize) {
+ if (chdir(daemon_root) != 0) {
+ log_warning("failed to change working directory to %s",
+ daemon_root);
+ } else {
+ log_info("changed directory to %s", daemon_root);
+ }
+ }
+
+ /* Now we're going multithreaded. */
+ rcu_register_thread();
+
+ /* Populate zone database. */
+ log_info("loading %zu zones", conf_id_count(conf(), C_ZONE));
+ server_update_zones(conf(), &server, RELOAD_ZONES);
+
+ /* Check number of loaded zones. */
+ if (knot_zonedb_size(server.zone_db) == 0) {
+ log_warning("no zones loaded");
+ }
+
+ stats_reconfigure(conf(), &server);
+
+ /* Start it up. */
+ log_info("starting server");
+ conf_val_t async_val = conf_get(conf(), C_SRV, C_ASYNC_START);
+ ret = server_start(&server, conf_bool(&async_val));
+ if (ret != KNOT_EOK) {
+ log_fatal("failed to start server (%s)", knot_strerror(ret));
+ server_wait(&server);
+ stats_deinit();
+ server_deinit(&server);
+ rcu_unregister_thread();
+ pid_cleanup();
+ conf_free(conf());
+ systemd_dbus_close();
+ log_close();
+ dnssec_crypto_cleanup();
+ return EXIT_FAILURE;
+ }
+
+ if (daemonize) {
+ log_info("server started as a daemon, PID %lu", pid);
+ } else {
+ log_info("server started in the foreground, PID %lu", pid);
+ }
+
+ /* Start the event loop. */
+ event_loop(&server, socket);
+
+ /* Teardown server. */
+ server_stop(&server);
+ server_wait(&server);
+ stats_deinit();
+
+ /* Cleanup PID file. */
+ pid_cleanup();
+
+ /* Free server and configuration. */
+ server_deinit(&server);
+ conf_free(conf());
+
+ /* Unhook from RCU. */
+ rcu_unregister_thread();
+
+ systemd_dbus_close();
+
+ log_info("shutting down");
+ log_close();
+
+ dnssec_crypto_cleanup();
+
+ return EXIT_SUCCESS;
+}
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