radiusd.c

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/*
 *   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 2 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, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/**
 * $Id: 544f1427c69f786825fc41529dc713e9d8a78542 $
 *
 * @file radiusd.c
 * @brief Main loop of the radius server.
 *
 * @copyright 2000-2018 The FreeRADIUS server project
 * @copyright 1999,2000 Miquel van Smoorenburg (miquels@cistron.nl)
 * @copyright 2000 Alan DeKok (aland@freeradius.org)
 * @copyright 2000 Alan Curry (pacman-radius@cqc.com)
 * @copyright 2000 Jeff Carneal (jeff@apex.net)
 * @copyright 2000 Chad Miller (cmiller@surfsouth.com)
 */
RCSID("$Id: 544f1427c69f786825fc41529dc713e9d8a78542 $")
 
#include <freeradius-devel/server/base.h>
#include <freeradius-devel/server/radmin.h>
#include <freeradius-devel/server/snmp.h>
#include <freeradius-devel/util/size.h>
 
#include <freeradius-devel/io/thread.h>
 
#include <freeradius-devel/tls/base.h>
#include <freeradius-devel/tls/log.h>
 
#include <freeradius-devel/unlang/base.h>
 
#include <freeradius-devel/util/misc.h>
#include <freeradius-devel/util/syserror.h>
 
#ifdef HAVE_CAPABILITY_H
#include <freeradius-devel/util/cap.h>
#endif
 
#include <fcntl.h>
#include <sys/file.h>
#include <sys/mman.h>
 
#ifdef HAVE_GETOPT_H
#  include <getopt.h>
#endif
 
#ifdef HAVE_SYS_WAIT_H
#  include <sys/wait.h>
#endif
#ifndef WEXITSTATUS
#  define WEXITSTATUS(stat_val) ((unsigned)(stat_val) >> 8)
#endif
#ifndef WIFEXITED
#  define WIFEXITED(stat_val) (((stat_val) & 255) == 0)
#endif
 
#ifdef HAVE_SYSTEMD
#  include <systemd/sd-daemon.h>
#endif
 
#ifdef WITH_TLS
#  include <freeradius-devel/tls/version.h>
#endif
 
char const      *radiusd_version = RADIUSD_VERSION_BUILD("FreeRADIUS");
static pid_t    radius_pid;
static char const       *program = NULL;
 
/*
 *  Configuration items.
 */
 
/*
 *      Static functions.
 */
static void usage(int status);
 
static void sig_fatal (int);
#ifdef SIGHUP
static void sig_hup (int);
#endif
 
/** Configure talloc debugging features
 *
 * @param[in] config    The main config.
 * @return
 *      - 1 on config conflict.
 *      - 0 on success.
 *      - -1 on error.
 */
static int talloc_config_set(main_config_t *config)
{
        if (config->spawn_workers) {
                if (config->talloc_memory_report) {
                        fr_strerror_printf("talloc_memory_report requires single threaded mode (-s | -X)");
                        return 1;
                }
                return 0;
        }
 
        if (!config->talloc_memory_report) {
                talloc_disable_null_tracking();
                return 0;
        }
 
        talloc_enable_null_tracking();
 
        return 0;
}
 
 
/** Create module and xlat per-thread instances
 *
 */
static int thread_instantiate(TALLOC_CTX *ctx, fr_event_list_t *el, UNUSED void *uctx)
{
        if (fr_thread_instantiate(ctx, el) < 0) return -1;
 
        if (modules_rlm_coord_attach(el) < 0) return -1;
 
        return 0;
}
 
/** Explicitly cleanup module/xlat resources
 *
 */
static void thread_detach(UNUSED void *uctx)
{
        fr_thread_detach();
}
 
#define EXIT_WITH_FAILURE \
do { \
        ret = EXIT_FAILURE; \
        goto cleanup; \
} while (0)
 
#define EXIT_WITH_SUCCESS \
do { \
        ret = EXIT_SUCCESS; \
        goto cleanup; \
} while (0)
 
#define EXIT_WITH_PERROR \
do { \
        fr_perror("%s", program); \
        EXIT_WITH_FAILURE; \
} while (0)
 
static fr_timer_t *fr_time_sync_ev = NULL;
 
static void fr_time_sync_event(fr_timer_list_t *tl, UNUSED fr_time_t now, UNUSED void *uctx)
{
        fr_time_delta_t when = fr_time_delta_from_sec(1);
 
        (void) fr_timer_in(tl, tl, &fr_time_sync_ev, when, false, fr_time_sync_event, NULL);
        (void) fr_time_sync();
}
 
#ifndef NDEBUG
/** Encourage the server to exit after a period of time
 *
 * @param[in] tl        The main loop.
 * @param[in] now       Current time.  Should be 0, when adding the event.
 * @param[in] uctx      Pointer to a fr_time_delta_t indicating how long
 *                      the server should run before exit.
 */
static void fr_exit_after(fr_timer_list_t *tl, fr_time_t now, void *uctx)
{
        static fr_timer_t *ev;
 
        fr_time_delta_t exit_after = *(fr_time_delta_t *)uctx;
 
        if (fr_time_eq(now, fr_time_wrap(0))) {
                if (fr_timer_in(tl, tl, &ev, exit_after, false, fr_exit_after, uctx) < 0) {
                        PERROR("%s: Failed inserting exit event", program);
                }
                return;
        }
 
        main_loop_signal_raise(RADIUS_SIGNAL_SELF_TERM);
}
#endif
 
#ifdef HAVE_CAPABILITY_H
#define DUMP_CAPABILITIES(_phase) \
{ \
        char *cap_str; \
        if (fr_cap_set_to_str(talloc_autofree_context(), &cap_str) < 0) { \
                PWARN("Failed retrieving %s capabilities", _phase); \
        } else { \
                INFO("%s capabilities: %s", _phase, cap_str); \
                talloc_free(cap_str); \
        } \
}
#else
#define DUMP_CAPABILITIES(_phase)
#endif
 
/** Entry point for the daemon
 *
 * @hidecallgraph
 */
int main(int argc, char *argv[])
{
        int                     status;
        int                     c;
        bool                    display_version = false;
        bool                    radmin = false;
        int                     from_child[2] = {-1, -1};
        fr_schedule_t           *sc = NULL;
        int                     ret = EXIT_SUCCESS;
 
        TALLOC_CTX              *global_ctx = NULL;
        main_config_t           *config = NULL;
        bool                    talloc_memory_report = false;
 
        bool                    confdir_set = false;
 
        size_t                  pool_size = 0;
        void                    *pool_page_start = NULL;
        size_t                  pool_page_len = 0;
        bool                    do_mprotect;
        int                     std_fd[3];
 
#ifndef NDEBUG
        fr_time_delta_t exit_after = fr_time_delta_wrap(0);
#endif
        /*
         *      Must be called first, so the handler is called last
         */
        fr_atexit_global_setup();
 
        /*
         *      Setup talloc callbacks so we get useful errors
         */
        (void) fr_talloc_fault_setup();
 
        /*
         *      Set some default values
         */
        program = strrchr(argv[0], FR_DIR_SEP);
        if (!program) {
                program = argv[0];
        } else {
                program++;
        }
 
        /*
         *      We probably don't want to free the talloc global_ctx context
         *      directly, so we'll allocate a new context beneath it, and
         *      free that before any leak reports.
         */
        {
                char *env;
 
                /*
                 *      If a FR_GLOBAL_POOL value is provided and
                 *      is of a valid size, we pre-allocate a global
                 *      memory pool, and mprotect() it once we're done
                 *      parsing the global config.
                 *
                 *      This lets us catch stray writes into global
                 *      memory.
                 */
                env = getenv("FR_GLOBAL_POOL");
                if (env) {
                        if (fr_size_from_str(&pool_size, &FR_SBUFF_IN_STR(env)) < 0) {
                                fr_perror("%s: Invalid pool size string \"%s\"", program, env);
                                EXIT_WITH_FAILURE;
                        }
 
                        /*
                         *      Pre-allocate a global memory pool for the static
                         *      config to exist in.  We mprotect() this later to
                         *      catch any stray writes.
                         */
                        global_ctx = talloc_page_aligned_pool(talloc_autofree_context(),
                                                              &pool_page_start, &pool_page_len, 0, pool_size);
                        do_mprotect = true;
                } else {
                        global_ctx = talloc_new(talloc_autofree_context());
                        do_mprotect = false;
                }
 
                if (!global_ctx) {
                        fprintf(stderr, "Failed allocating global context\n");
                        EXIT_WITH_FAILURE;
                }
        }
 
        /*
         *      Allocate the main config structure.
         *      It's allocated so we can hang talloced buffers off it.
         */
        config = main_config_alloc(global_ctx);
        if (!config) {
                fprintf(stderr, "Failed allocating main config");
                EXIT_WITH_FAILURE;
        }
 
        main_config_name_set_default(config, program, false);
 
        config->daemonize = true;
        config->spawn_workers = true;
 
        fr_debug_lvl = 0;
        fr_time_start();
 
        /*
         *      Don't put output anywhere until we get told a little
         *      more.
         */
        default_log.dst = L_DST_NULL;
        default_log.fd = -1;
        default_log.print_level = true;
        default_log.suppress_secrets = true;
 
        /*
         *  Set the panic action and enable other debugging facilities
         */
        if (fr_fault_setup(global_ctx, getenv("PANIC_ACTION"), argv[0], PANIC_ACTION_SIGNALS) < 0) {
                fr_perror("%s: Failed installing fault handlers... continuing", program);
        }
 
        /*  Process the options.  */
        while ((c = getopt(argc, argv, "Cd:D:e:fhl:Mmn:PrsS:tTvxX")) != -1) switch (c) {
                case 'C':
                        check_config = true;
                        config->spawn_workers = false;
                        config->daemonize = false;
                        break;
 
                case 'd':
                        main_config_confdir_set(config, optarg);
                        confdir_set = true;
                        break;
 
                case 'D':
                        main_config_dict_dir_set(config, optarg);
                        break;
 
                case 'e':
                        /*
                         *      For non-debug builds, accept '-e', but ignore it.
                         */
#ifndef NDEBUG
                        exit_after = fr_time_delta_from_sec(atoi(optarg));
#endif
                        break;
 
                case 'f':
                        config->daemonize = false;
                        break;
 
                case 'h':
                        usage(EXIT_SUCCESS);
                        break;
 
                case 'l':
                        if (strcmp(optarg, "stdout") == 0) goto do_stdout;
 
                        config->log_file = talloc_strdup(global_ctx, optarg);
                        default_log.file = talloc_strdup(global_ctx, optarg);
                        default_log.dst = L_DST_FILES;
                        default_log.fd = open(config->log_file, O_WRONLY | O_APPEND | O_CREAT, 0640);
                        if (default_log.fd < 0) {
                                fprintf(stderr, "%s: Failed to open log file %s: %s\n",
                                        program, config->log_file, fr_syserror(errno));
                                EXIT_WITH_FAILURE;
                        }
                        break;
 
                case 'm':
                        config->allow_multiple_procs = true;
                        break;
 
                case 'M':
                        config->talloc_memory_report = true;
                        break;
 
                case 'n':
                        main_config_name_set_default(config, optarg, true);
                        break;
 
                case 'P':       /* Force the PID to be written, even in -f mode */
                        config->write_pid = true;
                        break;
 
                case 'r':       /* internal radmin-style control interface */
                        config->spawn_workers = false;
                        config->daemonize = false;
                        radmin = true;
                        break;
 
                case 's':       /* Single process mode */
                        config->spawn_workers = false;
                        config->daemonize = false;
                        break;
 
                case 'S':       /* Migration support */
                        if (main_config_save_override(optarg) < 0) {
                                fprintf(stderr, "%s: Failed saving configuration option '%s' - %s\n",
                                        program, optarg, fr_strerror());
                                EXIT_WITH_FAILURE;
                        }
                        break;
 
                case 't':       /* no child threads */
                        config->spawn_workers = false;
                        break;
 
                case 'T':       /* enable timestamps */
                        default_log.timestamp = L_TIMESTAMP_ON;
                        break;
 
                case 'v':
                        display_version = true;
                        break;
 
                case 'X':
                        config->spawn_workers = false;
                        config->daemonize = false;
                        fr_debug_lvl += 2;
 
        do_stdout:
                        default_log.dst = L_DST_STDOUT;
                        default_log.fd = STDOUT_FILENO;
                        break;
 
                case 'x':
                        fr_debug_lvl++;
                        break;
 
                default:
                        usage(EXIT_FAILURE);
                        break;
        }
 
        if (fr_debug_lvl > 2) default_log.suppress_secrets = false;
 
        /*
         *      Allow the configuration directory to be set from an
         *      environment variable.  This allows tests to change the
         *      configuration directory without changing the scripts
         *      being executed.
         */
        if (!confdir_set) {
                char const *confdir = getenv("FREERADIUS_CONFIG_DIR");
 
                if (confdir) main_config_confdir_set(config, confdir);
        }
 
        /*
         *      We've now got enough information to check to see
         *      if another process is running with the same config.
         */
        config->debug_level = fr_debug_lvl;
 
        /*
         *  Mismatch between the binary and the libraries it depends on.
         */
        if (fr_check_lib_magic(RADIUSD_MAGIC_NUMBER) < 0) {
                EXIT_WITH_PERROR;
        }
 
        if (rad_check_lib_magic(RADIUSD_MAGIC_NUMBER) < 0) EXIT_WITH_FAILURE;
 
#ifdef WITH_TLS
        /*
         *  Mismatch between build time OpenSSL and linked SSL, better to die
         *  here than segfault later.
         */
        if (fr_openssl_version_consistent() < 0) EXIT_WITH_FAILURE;
 
        /*
         *  Initialising OpenSSL once, here, is safer than having individual modules do it.
         *  Must be called before display_version to ensure relevant engines are loaded.
         *
         *  fr_openssl_init() must be called before *ANY* OpenSSL functions are used, which is why
         *  it's called so early.
         */
        if (fr_openssl_init() < 0) EXIT_WITH_FAILURE;
#endif
 
        /*
         *  According to the talloc peeps, no two threads may modify any part of
         *  a ctx tree with a common root without synchronisation.
         *
         *  So we can't run with a null context and threads.
         */
        if (talloc_config_set(config) != 0) {
                EXIT_WITH_PERROR;
        }
 
        /*
         *  Better here, so it doesn't matter whether we get passed -xv or -vx.
         */
        if (display_version) {
                if (fr_debug_lvl == 0) fr_debug_lvl = 1;
                default_log.dst = L_DST_STDOUT;
                default_log.fd = STDOUT_FILENO;
 
                INFO("%s - %s", program, radiusd_version);
                dependency_version_print();
                EXIT_WITH_SUCCESS;
        }
 
        if (fr_debug_lvl) dependency_version_print();
 
#ifdef WITH_VERIFY_PTR
        WARN(" ");
        WARN("#######################################################################");
        WARN("# ");
        WARN("# The server was built with the 'WITH_VERIFY_PTR' flag set.  This is a");
        WARN("# developer-only build option that DRASTICALLY slows down the server.");
        WARN("# If you are using the server in a production environment, you will see");
        WARN("# significantly improved performance (3x-4x) by re-running 'configure'");
        WARN("# with the flag '--disable-developer', and then re-building and");
        WARN("# re-installing the server.");
        WARN("# ");
        WARN("#######################################################################");
        WARN(" ");
#endif
 
        /*
         *  Under linux CAP_SYS_PTRACE is usually only available before setuid/setguid,
         *  so we need to check whether we can attach before calling those functions
         *  (in main_config_init()).
         */
        fr_debug_state_store();
 
        /*
         *  Write the PID always if we're running as a daemon.
         */
        if (config->daemonize) config->write_pid = true;
 
        /*
         *      Initialize the DL infrastructure, which is used by the
         *      config file parser.  Note that we pass an empty path
         *      here, as we haven't yet read the configuration file.
         */
        modules_init(NULL);
 
        /*
         *      Initialise the top level dictionary hashes which hold
         *      the protocols.
         */
        if (!fr_dict_global_ctx_init(NULL, true, config->dict_dir)) {
                EXIT_WITH_PERROR;
        }
 
#ifdef WITH_TLS
        if (fr_tls_dict_init() < 0) {
                EXIT_WITH_PERROR;
        }
#endif
 
        /*
         *      Setup the global structures for module lists
         */
        if (modules_rlm_init() < 0) {
                EXIT_WITH_PERROR;
        }
 
        if (virtual_servers_init() < 0) {
                EXIT_WITH_PERROR;
        }
 
        /*
         *      Load dictionary attributes used
         *      for requests.
         */
        if (request_global_init() < 0) {
                EXIT_WITH_PERROR;
        }
 
        /*
         *      The radmin functions need to write somewhere.
         *
         *      The log functions redirect stdin and stdout to /dev/null, so that exec'd programs can't mangle
         *      them.  But radmin needs to be able to use them.
         */
#define RDUP(_x) \
do { \
        if ((std_fd[_x] = dup(_x)) < 0) EXIT_WITH_PERROR; \
        if (fr_cloexec(std_fd[_x]) < 0) EXIT_WITH_PERROR; \
} while (0)
 
        if (radmin) {
                RDUP(STDIN_FILENO);
                RDUP(STDOUT_FILENO);
                RDUP(STDERR_FILENO);
        }
 
        /*
         *  Read the configuration files, BEFORE doing anything else.
         */
        if (main_config_init(config) < 0) EXIT_WITH_FAILURE;
 
        /*
         *      Suppress secrets if asked, and if at a low debug level.
         */
        default_log.suppress_secrets = config->suppress_secrets && (fr_debug_lvl <= 2);
 
        /*
         *  Check we're the only process using this config.
         */
        if (!config->allow_multiple_procs && !check_config) {
                switch (main_config_exclusive_proc(config)) {
                case 0:         /* No other processes running */
                        break;
 
                case -1:        /* Permissions error - fail open */
                        PWARN("%s: Process concurrency checks disabled", program);
                        break;
 
                case 1:
                default:        /* All other errors */
                        EXIT_WITH_PERROR;
                }
        }
 
        /*
         *  Set panic_action from the main config if one wasn't specified in the
         *  environment.
         */
        if (config->panic_action && !getenv("PANIC_ACTION") &&
            (fr_fault_setup(global_ctx, config->panic_action, argv[0], PANIC_ACTION_SIGNALS) < 0)) {
                fr_perror("%s: Failed configuring panic action", program);
                EXIT_WITH_FAILURE;
        }
 
        /*
         *  This is very useful in figuring out why the panic_action didn't fire.
         */
        INFO("%s", fr_debug_state_to_msg(fr_debug_state));
 
        /*
         *      Track configuration versions.  This lets us know if the configuration changed.
         */
        if (fr_debug_lvl) {
                uint8_t digest[16];
 
                cf_md5_final(digest);
 
                digest[6] &= 0x0f; /* ver is 0b0100 at bits 48:51 */
                digest[6] |= 0x40;
                digest[8] &= ~0xc0; /* var is 0b10 at bits 64:65 */
                digest[8] |= 0x80;
 
                /*
                 *      UUIDv4 format: 4-2-2-2-6
                 */
                INFO("Configuration version: %02X%02X%02X%02X-%02X%02X-%02X%02X-%02X%02X-%02X%02X%02X%02X%02X%02X",
                     digest[0], digest[1], digest[2], digest[3], digest[4], digest[5], digest[6], digest[7],
                     digest[8], digest[9], digest[10], digest[11], digest[12], digest[13], digest[14], digest[15]);
        }
 
        /*
         *  Call this again now we've loaded the configuration. Yes I know...
         */
        if (talloc_config_set(config) != 0) {
                EXIT_WITH_PERROR;
        }
 
        /*
         *  Check for vulnerabilities in the version of libssl were linked against.
         */
#ifdef WITH_TLS
#  ifdef ENABLE_OPENSSL_VERSION_CHECK
        if (fr_openssl_version_check(config->allow_vulnerable_openssl) < 0) EXIT_WITH_FAILURE;
#  endif
 
        /*
         *  Toggle FIPS mode
         */
        if (config->openssl_fips_mode_is_set &&
            (fr_openssl_fips_mode(config->openssl_fips_mode) < 0)) EXIT_WITH_FAILURE;
#endif
 
        /*
         *  The systemd watchdog enablement must be checked before we
         *  daemonize, but the watchdog notifications can come from any
         *  process.
         */
#ifdef HAVE_SYSTEMD_WATCHDOG
        if (!check_config) main_loop_set_sd_watchdog_interval();
#else
        /*
         *      If the default systemd unit file is used, but the server wasn't
         *      built with support for systemd, the status returned by systemctl
         *      will stay permanently as "activating".
         *
         *      We detect this condition and warn about it here, using the
         *      presence of the NOTIFY_SOCKET environmental variable to determine
         *      whether we're running under systemd.
         */
        if (getenv("NOTIFY_SOCKET")) INFO("Built without support for systemd watchdog, but running under systemd");
#endif
 
        /*
         *      Don't allow radmin when checking the config.
         */
        if (check_config) radmin = false;
 
        if (fr_radmin_start(config, radmin, std_fd) < 0) EXIT_WITH_FAILURE;
 
        /*
         *  Disconnect from session
         */
        if (config->daemonize) {
                pid_t pid;
                int devnull;
 
                DUMP_CAPABILITIES("pre-fork");
 
                /*
                 *  Really weird things happen if we leave stdin open and call things like
                 *  system() later.
                 *
                 *  main_config_init() already calls fr_log_init_legacy(), which closes stdout/stderr.
                 */
                devnull = open("/dev/null", O_RDWR);
                if (devnull < 0) {
                        ERROR("Failed opening /dev/null: %s", fr_syserror(errno));
                        EXIT_WITH_FAILURE;
                }
                dup2(devnull, STDIN_FILENO);
 
                close(devnull);
 
                if (pipe(from_child) != 0) {
                        ERROR("Couldn't open pipe for child status: %s", fr_syserror(errno));
                        EXIT_WITH_FAILURE;
                }
 
                pid = fork();
                if (pid < 0) {
                        ERROR("Couldn't fork: %s", fr_syserror(errno));
                        EXIT_WITH_FAILURE;
                }
 
                /*
                 *  The parent exits, so the child can run in the background.
                 *
                 *  As the child can still encounter an error during initialisation
                 *  we do a blocking read on a pipe between it and the parent.
                 *
                 *  Just before entering the event loop the child will send a success
                 *  or failure message to the parent, via the pipe.
                 */
                if (pid > 0) {
                        uint8_t child_ret;
                        int stat_loc;
 
                        /* So the pipe is correctly widowed if the child exits */
                        close(from_child[1]);
 
                        /*
                         *  The child writes a 0x01 byte on success, and closes
                         *  the pipe on error.
                         */
                        if ((read(from_child[0], &child_ret, 1) <= 0)) child_ret = 0;
 
                        /* For cleanliness... */
                        close(from_child[0]);
 
                        /* Don't turn children into zombies */
                        if (child_ret == 0) {
                                waitpid(pid, &stat_loc, WNOHANG);
                                EXIT_WITH_FAILURE;
                        }
 
#ifdef HAVE_SYSTEMD
                        /*
                         *      Update the systemd MAINPID to be our child,
                         *      as the parent is about to exit.
                         */
                        sd_notifyf(0, "MAINPID=%lu", (unsigned long)pid);
#endif
 
                        goto cleanup;
                /*
                 *  The child needs to increment the semaphore as the parent
                 *  is going to exit, and it will decrement the semaphore.
                 */
                } else if (pid == 0) {
                        if (main_config_exclusive_proc_child(main_config) < 0) {
                                PWARN("%s: Failed incrementing exclusive proc semaphore in child", program);
                        }
                }
 
                /* so the pipe is correctly widowed if the parent exits?! */
                close(from_child[0]);
#ifdef HAVE_SETSID
                setsid();
#endif
 
                DUMP_CAPABILITIES("post-fork");
        } else {
                DUMP_CAPABILITIES("pre-suid-down");
        }
 
        /*
         *  Ensure that we're using the CORRECT pid after forking, NOT the one
         *  we started with.
         */
        radius_pid = getpid();
 
        /*
         *      Initialise the interpreter, registering operations.
         */
        if (unlang_global_init() < 0) EXIT_WITH_FAILURE;
 
        /*
         *  Initialize the global event loop which handles things like
         *  systemd.
         *
         *  This has to be done post-fork in case we're using kqueue, where the
         *  queue isn't inherited by the child process.
         *
         *  Done before `server_init` so that module instantiate callbacks can
         *  register fds / timers against `main_loop_event_list()` directly.
         *  `main_loop_init` has no dependencies on module or virtual server
         *  state, so this reordering is safe.
         */
        if (main_loop_init() < 0) {
                PERROR("Failed initialising main event loop");
                EXIT_WITH_FAILURE;
        }
 
        if (server_init(config->root_cs, config->confdir, fr_dict_unconst(fr_dict_internal())) < 0) EXIT_WITH_FAILURE;
 
        /*
         *  Everything seems to have loaded OK, exit gracefully.
         */
        if (check_config) {
                DEBUG("Configuration appears to be OK");
                goto cleanup;
        }
 
        /*
         *      Initialise the SNMP stats structures
         */
        if (fr_snmp_init() < 0) {
                PERROR("Failed initialising SNMP");
                EXIT_WITH_FAILURE;
        }
 
        /*
         *      Start the network / worker threads.
         */
        {
                fr_schedule_config_t *schedule;
 
                MEM(schedule = talloc_zero(global_ctx, fr_schedule_config_t));
                schedule->max_workers = config->max_workers;
                schedule->max_networks = config->max_networks;
                schedule->stats_interval = config->stats_interval;
 
                schedule->network.max_outstanding = config->worker.max_requests;
                schedule->worker = config->worker;
                schedule->cs = cf_section_find(config->root_cs, "thread", CF_IDENT_ANY);
 
                /*
                 *      Fix spurious messages
                 */
                fr_strerror_clear();
                sc = fr_schedule_create(NULL, !config->spawn_workers, main_loop_event_list(),
                                        &default_log, fr_debug_lvl,
                                        thread_instantiate, thread_detach, schedule);
                if (!sc) {
                        PERROR("Failed starting the scheduler");
                        EXIT_WITH_FAILURE;
                }
 
                /*
                 *      Tell the virtual servers to open their sockets.
                 */
                if (virtual_servers_open(sc) < 0) EXIT_WITH_FAILURE;
        }
 
        /*
         *      At this point, no one has any business *ever* going
         *      back to root uid.
         */
        rad_suid_down_permanent();
 
        /*
         *      Move the current working directory to a place where it
         *      can't hurt anything.
         */
        if (main_config->chdir_is_set) {
                if (chdir(main_config->chdir) < 0) {
                        ERROR("Failed changing working to %s: %s", main_config->chdir, fr_syserror(errno));
                        EXIT_WITH_FAILURE;
                }
        }
 
        DUMP_CAPABILITIES("post-suid-down");
 
        /*
         *      Dropping down may change the RLIMIT_CORE value, so
         *      reset it back to what to should be here.
         */
        fr_reset_dumpable();
 
        /*
         *  If we're debugging, then a CTRL-C will cause the server to die
         *  immediately.  Use SIGTERM to shut down the server cleanly in
         *  that case.
         */
        if (fr_set_signal(SIGINT, sig_fatal) < 0) {
        set_signal_error:
                PERROR("Failed installing signal handler");
                EXIT_WITH_FAILURE;
        }
 
#ifdef SIGQUIT
        if (fr_set_signal(SIGQUIT, sig_fatal) < 0) goto set_signal_error;
#endif
 
        /*
         *  Now that we've set everything up, we can install the signal
         *  handlers.  Before this, if we get any signal, we don't know
         *  what to do, so we might as well do the default, and die.
         */
#ifdef SIGPIPE
        if (signal(SIGPIPE, SIG_IGN) == SIG_ERR) {
                ERROR("Failed ignoring SIGPIPE: %s", fr_syserror(errno));
                goto cleanup;
        }
#endif
 
        if (fr_set_signal(SIGHUP, sig_hup) < 0) goto set_signal_error;
        if (fr_set_signal(SIGTERM, sig_fatal) < 0) goto set_signal_error;
 
        /*
         *  Write the PID after we've forked, so that we write the correct one.
         */
        if (config->write_pid) {
                FILE *fp;
 
                fp = fopen(config->pid_file, "w");
                if (fp != NULL) {
                        /*
                         *  @fixme What about following symlinks,
                         *  and having it over-write a normal file?
                         */
                        fprintf(fp, "%d\n", (int) radius_pid);
                        fclose(fp);
                } else {
                        ERROR("Failed creating PID file %s: %s", config->pid_file, fr_syserror(errno));
                        EXIT_WITH_FAILURE;
                }
        }
 
        trigger(NULL, NULL, NULL, "server.start", false, NULL, NULL);
 
        /*
         *  Inform the parent (who should still be waiting) that the rest of
         *  initialisation went OK, and that it should exit with a 0 status.
         *  If we don't get this far, then we just close the pipe on exit, and the
         *  parent gets a read failure.
         */
        if (config->daemonize) {
                if (write(from_child[1], "\001", 1) < 0) {
                        WARN("Failed informing parent of successful start: %s",
                             fr_syserror(errno));
                }
                close(from_child[1]);
        }
 
        /*
         *      Clear the libfreeradius error buffer.
         */
        fr_strerror_clear();
 
        /*
         *      Prevent anything from modifying the dictionaries
         *      they're now immutable.
         */
        fr_dict_global_ctx_read_only();
 
        /*
         *  Protect global memory - If something attempts
         *  to write to this memory we get a SIGBUS.
         */
        if (do_mprotect) {
                if (mprotect(pool_page_start, pool_page_len, PROT_READ) < 0) {
                        ERROR("Protecting global memory failed: %s", fr_syserror(errno));
                        EXIT_WITH_FAILURE;
                }
                DEBUG("Global memory protected");
        }
 
        fr_time_sync_event(main_loop_event_list()->tl, fr_time(), NULL);
#ifndef NDEBUG
        if (fr_time_delta_ispos(exit_after)) fr_exit_after(main_loop_event_list()->tl, fr_time_wrap(0), &exit_after);
#endif
        /*
         *  Process requests until HUP or exit.
         */
        INFO("Ready to process requests");      /* we were actually ready a while ago, but oh well */
        while ((status = main_loop_start()) == 0x80) {
                main_config_hup(config);
        }
 
        /*
         *  Ignore the TERM signal: we're about to die.
         */
        if (unlikely(signal(SIGTERM, SIG_IGN) == SIG_ERR)) {
                ERROR("Failed blocking SIGTERM, we may receive spurious signals: %s",
                      fr_syserror(errno));
        }
 
        /*
         *  Unprotect global memory
         */
        if (do_mprotect) {
                if (mprotect(pool_page_start, pool_page_len,
                             PROT_READ | PROT_WRITE) < 0) {
                        ERROR("Unprotecting global memory failed: %s", fr_syserror(errno));
                        EXIT_WITH_FAILURE;
                }
                DEBUG("Global memory unprotected");
        }
 
        if (status < 0) {
                PERROR("Exiting due to internal error");
                ret = EXIT_FAILURE;
        } else {
                INFO("Exiting normally");
                ret = EXIT_SUCCESS;
        }
 
        fr_radmin_stop();
 
        /*
         *   Fire signal and stop triggers after ignoring SIGTERM, so handlers are
         *   not killed with the rest of the process group, below.
         */
        if (status == 2) trigger(NULL, NULL, NULL, "server.signal.term", true, NULL, NULL);
        trigger(NULL, NULL, NULL, "server.stop", false, NULL, NULL);
 
        /*
         *  Stop the scheduler, this signals the network and worker threads
         *  to exit gracefully.  fr_schedule_destroy only returns once all
         *  threads have been joined.
         */
        if (unlikely(fr_schedule_destroy(&sc) < 0)) {
                EXIT_WITH_PERROR;
        }
 
        /*
         *  We're exiting, so we can delete the PID file.
         *  (If it doesn't exist, we can ignore the error returned by unlink)
         */
        if (config->daemonize) {
                DEBUG3("Unlinking PID file %s", config->pid_file);
                unlink(config->pid_file);
        }
 
        /*
         *  Free memory in an explicit and consistent order
         *
         *  We could let everything be freed by the global_ctx
         *  context, but in some cases there are odd interactions
         *  with destructors that may cause double frees and
         *  SEGVs.
         */
        if (!config->spawn_workers) {
                fr_event_list_t *el;
 
                el = main_loop_event_list();
                fr_event_loop_exit(el, 1);
        }
 
        main_loop_free();
 
        /*
         *  Send a TERM signal to all associated processes
         *  (including us, which gets ignored.)
         *
         *  This _shouldn't_ be needed, but may help with
         *  processes created by the exec code or triggers.
         *
         *  Only do this when we lead the process group, i.e. when
         *  we daemonized (setsid), or a supervisor such as systemd
         *  or a container runtime gave us our own group.  When run
         *  in the foreground from a shell the group belongs to the
         *  shell, and signalling it would take out the shell and
         *  its terminal along with our children.
         */
        if (config->spawn_workers && (getpgid(0) == radius_pid)) {
                INFO("All threads have exited, sending SIGTERM to remaining children");
 
                /*
                 *      If pid is negative, but not -1, sig
                 *      shall be sent to all processes
                 *      (excluding an unspecified set of system processes)
                 *      whose process group ID is equal to the absolute value
                 *      of pid, and for which the process has permission
                 *      to send a signal.
                 */
                kill(-getpgid(radius_pid), SIGTERM);
        }
 
        /*
         *      Remove the semaphore, allowing other processes
         *      to start.  We do this before the cleanup label
         *      as the parent process MUST NOT call this
         *      function as it exits, otherwise the semaphore
         *      is removed and there's no exclusivity.
         */
        main_config_exclusive_proc_done(main_config);
 
cleanup:
        /*
         *      If we're told to just exit without cleaning up memory,
         *      then do so.
         */
        if (config && config->talloc_skip_cleanup) {
                fr_atexit_global_disarm_all();
                exit(ret);
        }
 
        /*
         *      This may not have been done earlier if we're
         *      exiting due to a startup error.
         */
        (void) fr_schedule_destroy(&sc);
 
        /*
         *      Threads not managed by the schedule (e.g. librdkafka's
         *      bg threads) hold a `_Thread_local fr_log_pool` we can't
         *      clear from this thread.  `fr_atexit_thread_trigger_all`
         *      below frees the underlying chunks, leaving those slots
         *      dangling.  Flip the logger into pool-less mode first so
         *      any log line that races the trigger - or fires after it -
         *      goes through `talloc_new(NULL)` instead of dereferencing
         *      a freed pool.
         */
        fr_log_disable_pools();
 
        /*
         *      Ensure all thread local memory is cleaned up
         *      before we start cleaning up global resources.
         *      This is necessary for single threaded mode
         *      to ensure that thread local resources that
         *      depend on global resources are freed at the
         *      appropriate time.
         */
        fr_atexit_thread_trigger_all();
 
        server_free();
 
#ifdef WITH_TLS
        fr_openssl_free();              /* Cleanup any memory alloced by OpenSSL and placed into globals */
#endif
 
        if (config) talloc_memory_report = config->talloc_memory_report;        /* Grab this before we free the config */
 
        /*
         *      Virtual servers need to be freed before modules
         *      as state entries containing data with module-specific
         *      destructors may exist.
         */
        virtual_servers_free();
 
        /*
         *      Free modules, this needs to be done explicitly
         *      because some libraries used by modules use atexit
         *      handlers registered after ours, and they may deinit
         *      themselves before we free the modules and cause
         *      crashes on exit.
         */
        modules_rlm_free();
 
#ifdef WITH_TLS
        fr_tls_dict_free();
#endif
 
        /*
         *  And now nothing should be left anywhere except the
         *  parsed configuration items.
         */
        main_config_free(&config);
 
        /*
         *  Cleanup everything else
         */
        if (talloc_free(global_ctx) < 0) {
#ifndef NDEBUG
                fr_perror("program");
                ret = EXIT_FAILURE;
#endif
        }
 
        /*
         *  Anything not cleaned up by the above is allocated in
         *  the NULL top level context, and is likely leaked memory.
         */
        if (talloc_memory_report) fr_log_talloc_report(NULL);
 
        /*
         *  If we're running under LSAN, try and SUID back up so
         *  we don't inteferere with the onexit() handler.
         */
        if (!rad_suid_is_down_permanent() && (fr_get_lsan_state() == 1)) rad_suid_up();
        fr_strerror_clear();    /* clear error buffer */
 
        /*
         *      Ensure our atexit handlers run before any other
         *      atexit handlers registered by third party libraries.
         */
        fr_atexit_global_trigger_all();
 
        return ret;
}
 
/*
 *  Display the syntax for starting this program.
 */
static NEVER_RETURNS void usage(int status)
{
        FILE *output = status ? stderr : stdout;
 
        fprintf(output, "Usage: %s [options]\n", program);
        fprintf(output, "Options:\n");
        fprintf(output, "  -C            Check configuration and exit.\n");
        fprintf(output, "  -d <confdir>  Configuration file directory (defaults to " CONFDIR ").\n");
        fprintf(output, "  -D <dictdir>  Set main dictionary directory (defaults to " DICTDIR ").\n");
#ifndef NDEBUG
        fprintf(output, "  -e <seconds>  Exit after the specified number of seconds.  Useful for diagnosing \"crash-on-exit\" issues.\n");
#endif
        fprintf(output, "  -f            Run as a foreground process, not a daemon.\n");
        fprintf(output, "  -h            Print this help message.\n");
        fprintf(output, "  -l <log_file> Logging output will be written to this file.\n");
#ifndef NDEBUG
        fprintf(output, "  -L <size>     When running in memory debug mode, set a hard limit on talloced memory\n");
#endif
        fprintf(output, "  -n <name>     Read ${confdir}/name.conf instead of ${confdir}/%s.conf.\n", program);
        fprintf(output, "  -m            Allow multiple processes reading the same %s.conf to exist simultaneously.\n", program);
#ifndef NDEBUG
        fprintf(output, "  -M            Enable talloc memory debugging, and issue a memory report when the server terminates\n");
#endif
        fprintf(output, "  -P            Always write out PID, even with -f.\n");
        fprintf(output, "  -s            Do not spawn child processes to handle requests (same as -ft).\n");
 
        /*
         *      Place-holder in case we need it.  Should be removed before the release.
         */
//      fprintf(output, "  -S <flag>     Set migration flags to assist with upgrades from version 3.\n");
        fprintf(output, "  -t            Disable threads.\n");
        fprintf(output, "  -T            Prepend timestamps to  log messages.\n");
        fprintf(output, "  -v            Print server version information.\n");
        fprintf(output, "  -X            Turn on full debugging (similar to -tfxxl stdout).\n");
        fprintf(output, "  -x            Turn on additional debugging (-xx gives more debugging).\n");
        fr_exit(status);
}
 
 
/*
 *      We got a fatal signal.
 */
static void sig_fatal(int sig)
{
        static volatile sig_atomic_t last_sig;
 
        if (getpid() != radius_pid) _exit(sig);
 
        /*
         *      Suppress duplicate signals.
         *
         *      For some reason on macOS we get multiple signals
         *      for the same event (SIGINT).
         *
         *      ...this also fixes the problem of the user hammering
         *      Ctrl-C and causing ungraceful exits as we try and
         *      write out signals to a pipe that's already closed.
         */
        if (sig == last_sig) return;
        last_sig = sig;
 
        switch (sig) {
        case SIGTERM:
                main_loop_signal_raise(RADIUS_SIGNAL_SELF_TERM);
                break;
 
        case SIGINT:
#ifdef SIGQUIT
        case SIGQUIT:
#endif
                main_loop_signal_raise(RADIUS_SIGNAL_SELF_TERM);
                break;
 
        default:
                fr_exit(sig);
        }
}
 
#ifdef SIGHUP
/*
 *  We got the hangup signal.
 *  Re-read the configuration files.
 */
static void sig_hup(UNUSED int sig)
{
        reset_signal(SIGHUP, sig_hup);
 
        main_loop_signal_raise(RADIUS_SIGNAL_SELF_HUP);
}
#endif