/*
 * daemon/unbound.c - main program for unbound DNS resolver daemon.
 *
 * Copyright (c) 2007, NLnet Labs. All rights reserved.
 *
 * This software is open source.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * 
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 
 * Neither the name of the NLNET LABS nor the names of its contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

/**
 * \file
 *
 * Main program to start the DNS resolver daemon.
 */

#include "config.h"
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#endif
#include <sys/time.h>
#include "util/log.h"
#include "daemon/daemon.h"
#include "daemon/remote.h"
#include "util/config_file.h"
#include "util/storage/slabhash.h"
#include "services/listen_dnsport.h"
#include "services/cache/rrset.h"
#include "services/cache/infra.h"
#include "util/fptr_wlist.h"
#include "util/data/msgreply.h"
#include "util/module.h"
#include "util/net_help.h"
#include "util/ub_event.h"
#include <signal.h>
#include <fcntl.h>
#include <openssl/crypto.h>
#ifdef HAVE_PWD_H
#include <pwd.h>
#endif
#ifdef HAVE_GRP_H
#include <grp.h>
#endif
#include <openssl/ssl.h>

#ifndef S_SPLINT_S
/* splint chokes on this system header file */
#ifdef HAVE_SYS_RESOURCE_H
#include <sys/resource.h>
#endif
#endif /* S_SPLINT_S */
#ifdef HAVE_LOGIN_CAP_H
#include <login_cap.h>
#endif

#ifdef UB_ON_WINDOWS
#  include "winrc/win_svc.h"
#endif

#ifdef HAVE_NSS
/* nss3 */
#  include "nss.h"
#endif

#ifdef HAVE_TARGETCONDITIONALS_H
#include <TargetConditionals.h>
#endif

#if (defined(TARGET_OS_TV) && TARGET_OS_TV) || (defined(TARGET_OS_WATCH) && TARGET_OS_WATCH)
#undef HAVE_FORK
#endif

/** print build options. */
static void
print_build_options(void)
{
        const char** m;
        const char *evnm="event", *evsys="", *evmethod="";
        time_t t;
        struct timeval now;
        struct ub_event_base* base;
        printf("Version %s\n\n", PACKAGE_VERSION);
        printf("Configure line: %s\n", CONFCMDLINE);
        base = ub_default_event_base(0,&t,&now);
        ub_get_event_sys(base, &evnm, &evsys, &evmethod);
        printf("Linked libs: %s %s (it uses %s), %s\n",
                evnm, evsys, evmethod,
#ifdef HAVE_SSL
#  ifdef SSLEAY_VERSION
                SSLeay_version(SSLEAY_VERSION)
#  else
                OpenSSL_version(OPENSSL_VERSION)
#  endif
#elif defined(HAVE_NSS)
                NSS_GetVersion()
#elif defined(HAVE_NETTLE)
                "nettle"
#endif
                );
        printf("Linked modules:");
        for(m = module_list_avail(); *m; m++)
                printf(" %s", *m);
        printf("\n");
#ifdef USE_DNSCRYPT
        printf("DNSCrypt feature available\n");
#endif
#ifdef USE_TCP_FASTOPEN
        printf("TCP Fastopen feature available\n");
#endif
        ub_event_base_free(base);
        printf("\nBSD licensed, see LICENSE in source package for details.\n");
        printf("Report bugs to %s\n", PACKAGE_BUGREPORT);
}

/** print usage. */
static void
usage(void)
{
        printf("usage:  unbound [options]\n");
        printf("        start unbound daemon DNS resolver.\n");
        printf("-h      this help.\n");
        printf("-c file config file to read instead of %s\n", CONFIGFILE);
        printf("        file format is described in unbound.conf(5).\n");
        printf("-d      do not fork into the background.\n");
        printf("-p      do not create a pidfile.\n");
        printf("-v      verbose (more times to increase verbosity).\n");
        printf("-V      show version number and build options.\n");
#ifdef UB_ON_WINDOWS
        printf("-w opt  windows option: \n");
        printf("        install, remove - manage the services entry\n");
        printf("        service - used to start from services control panel\n");
#endif
        printf("\nVersion %s\n", PACKAGE_VERSION);
        printf("BSD licensed, see LICENSE in source package for details.\n");
        printf("Report bugs to %s\n", PACKAGE_BUGREPORT);
}

#ifndef unbound_testbound
int replay_var_compare(const void* ATTR_UNUSED(a), const void* ATTR_UNUSED(b))
{
        log_assert(0);
        return 0;
}
#endif

/** check file descriptor count */
static void
checkrlimits(struct config_file* cfg)
{
#ifndef S_SPLINT_S
#if defined(HAVE_GETRLIMIT) && !defined(unbound_testbound)
        /* list has number of ports to listen to, ifs number addresses */
        int list = ((cfg->do_udp?1:0) + (cfg->do_tcp?1 + 
                        (int)cfg->incoming_num_tcp:0));
        size_t listen_ifs = (size_t)(cfg->num_ifs==0?
                ((cfg->do_ip4 && !cfg->if_automatic?1:0) + 
                 (cfg->do_ip6?1:0)):cfg->num_ifs);
        size_t listen_num = list*listen_ifs;
        size_t outudpnum = (size_t)cfg->outgoing_num_ports;
        size_t outtcpnum = cfg->outgoing_num_tcp;
        size_t misc = 4; /* logfile, pidfile, stdout... */
        size_t perthread_noudp = listen_num + outtcpnum + 
                2/*cmdpipe*/ + 2/*libevent*/ + misc; 
        size_t perthread = perthread_noudp + outudpnum;

#if !defined(HAVE_PTHREAD) && !defined(HAVE_SOLARIS_THREADS)
        int numthread = 1; /* it forks */
#else
        int numthread = (cfg->num_threads?cfg->num_threads:1);
#endif
        size_t total = numthread * perthread + misc;
        size_t avail;
        struct rlimit rlim;
        size_t memsize_expect = cfg->msg_cache_size + cfg->rrset_cache_size
                + (cfg->do_tcp?cfg->stream_wait_size:0)
                + (cfg->ip_ratelimit?cfg->ip_ratelimit_size:0)
                + (cfg->ratelimit?cfg->ratelimit_size:0)
                + (cfg->dnscrypt?cfg->dnscrypt_shared_secret_cache_size + cfg->dnscrypt_nonce_cache_size:0)
                + cfg->infra_cache_numhosts * (sizeof(struct infra_key)+sizeof(struct infra_data));
        if(strstr(cfg->module_conf, "validator") && (cfg->trust_anchor_file_list || cfg->trust_anchor_list || cfg->auto_trust_anchor_file_list || cfg->trusted_keys_file_list)) {
                memsize_expect += cfg->key_cache_size + cfg->neg_cache_size;
        }
#ifdef HAVE_NGHTTP2_NGHTTP2_H
        if(cfg_has_https(cfg)) {
                memsize_expect += cfg->http_query_buffer_size + cfg->http_response_buffer_size;
        }
#endif

#ifdef RLIMIT_AS
        if(getrlimit(RLIMIT_AS, &rlim) == 0) {
                if(rlim.rlim_cur != (rlim_t)RLIM_INFINITY &&
                        rlim.rlim_cur < (rlim_t)memsize_expect) {
                        log_warn("the ulimit(max memory size) is smaller than the expected memory usage (added size of caches). %u < %u bytes", (unsigned)rlim.rlim_cur, (unsigned)memsize_expect);
                }
        }
#endif
        if(getrlimit(RLIMIT_DATA, &rlim) == 0) {
                if(rlim.rlim_cur != (rlim_t)RLIM_INFINITY &&
                        rlim.rlim_cur < (rlim_t)memsize_expect) {
                        log_warn("the ulimit(data seg size) is smaller than the expected memory usage (added size of caches). %u < %u bytes", (unsigned)rlim.rlim_cur, (unsigned)memsize_expect);
                }
        }

        if(total > 1024 && 
                strncmp(ub_event_get_version(), "mini-event", 10) == 0) {
                log_warn("too many file descriptors requested. The builtin"
                        "mini-event cannot handle more than 1024. Config "
                        "for less fds or compile with libevent");
                if(numthread*perthread_noudp+15 > 1024)
                        fatal_exit("too much tcp. not enough fds.");
                cfg->outgoing_num_ports = (int)((1024 
                        - numthread*perthread_noudp 
                        - 10 /* safety margin */) /numthread);
                log_warn("continuing with less udp ports: %u",
                        cfg->outgoing_num_ports);
                total = 1024;
        }
        if(perthread > 64 && 
                strncmp(ub_event_get_version(), "winsock-event", 13) == 0) {
                log_err("too many file descriptors requested. The winsock"
                        " event handler cannot handle more than 64 per "
                        " thread. Config for less fds");
                if(perthread_noudp+2 > 64)
                        fatal_exit("too much tcp. not enough fds.");
                cfg->outgoing_num_ports = (int)((64 
                        - perthread_noudp 
                        - 2/* safety margin */));
                log_warn("continuing with less udp ports: %u",
                        cfg->outgoing_num_ports);
                total = numthread*(perthread_noudp+
                        (size_t)cfg->outgoing_num_ports)+misc;
        }
        if(getrlimit(RLIMIT_NOFILE, &rlim) < 0) {
                log_warn("getrlimit: %s", strerror(errno));
                return;
        }
        if(rlim.rlim_cur == (rlim_t)RLIM_INFINITY)
                return;
        if((size_t)rlim.rlim_cur < total) {
                avail = (size_t)rlim.rlim_cur;
                rlim.rlim_cur = (rlim_t)(total + 10);
                rlim.rlim_max = (rlim_t)(total + 10);
#ifdef HAVE_SETRLIMIT
                if(setrlimit(RLIMIT_NOFILE, &rlim) < 0) {
                        log_warn("setrlimit: %s", strerror(errno));
#endif
                        log_warn("cannot increase max open fds from %u to %u",
                                (unsigned)avail, (unsigned)total+10);
                        /* check that calculation below does not underflow,
                         * with 15 as margin */
                        if(numthread*perthread_noudp+15 > avail)
                                fatal_exit("too much tcp. not enough fds.");
                        cfg->outgoing_num_ports = (int)((avail 
                                - numthread*perthread_noudp 
                                - 10 /* safety margin */) /numthread);
                        log_warn("continuing with less udp ports: %u",
                                cfg->outgoing_num_ports);
                        log_warn("increase ulimit or decrease threads, "
                                "ports in config to remove this warning");
                        return;
#ifdef HAVE_SETRLIMIT
                }
#endif
                verbose(VERB_ALGO, "increased limit(open files) from %u to %u",
                        (unsigned)avail, (unsigned)total+10);
        }
#else   
        (void)cfg;
#endif /* HAVE_GETRLIMIT */
#endif /* S_SPLINT_S */
}

/** set verbosity, check rlimits, cache settings */
static void
apply_settings(struct daemon* daemon, struct config_file* cfg,
        int cmdline_verbose, int debug_mode)
{
        /* apply if they have changed */
        verbosity = cmdline_verbose + cfg->verbosity;
        if (debug_mode > 1) {
                cfg->use_syslog = 0;
                free(cfg->logfile);
                cfg->logfile = NULL;
        }
        daemon_apply_cfg(daemon, cfg);
        checkrlimits(cfg);

        if (cfg->use_systemd && cfg->do_daemonize) {
                log_warn("use-systemd and do-daemonize should not be enabled at the same time");
        }

        log_ident_set_or_default(cfg->log_identity);
}

#ifdef HAVE_KILL
/** Read existing pid from pidfile. 
 * @param file: file name of pid file.
 * @return: the pid from the file or -1 if none.
 */
static pid_t
readpid (const char* file)
{
        int fd;
        pid_t pid;
        char pidbuf[32];
        char* t;
        ssize_t l;

        if ((fd = open(file, O_RDONLY)) == -1) {
                if(errno != ENOENT)
                        log_err("Could not read pidfile %s: %s",
                                file, strerror(errno));
                return -1;
        }

        if (((l = read(fd, pidbuf, sizeof(pidbuf)))) == -1) {
                if(errno != ENOENT)
                        log_err("Could not read pidfile %s: %s",
                                file, strerror(errno));
                close(fd);
                return -1;
        }

        close(fd);

        /* Empty pidfile means no pidfile... */
        if (l == 0) {
                return -1;
        }

        pidbuf[sizeof(pidbuf)-1] = 0;
        pid = (pid_t)strtol(pidbuf, &t, 10);
        
        if (*t && *t != '\n') {
                return -1;
        }
        return pid;
}

/** write pid to file. 
 * @param pidfile: file name of pid file.
 * @param pid: pid to write to file.
 */
static void
writepid (const char* pidfile, pid_t pid)
{
        int fd;
        char pidbuf[32];
        size_t count = 0;
        snprintf(pidbuf, sizeof(pidbuf), "%lu\n", (unsigned long)pid);

        if((fd = open(pidfile, O_WRONLY | O_CREAT | O_TRUNC
#ifdef O_NOFOLLOW
                | O_NOFOLLOW
#endif
                , 0644)) == -1) {
                log_err("cannot open pidfile %s: %s", 
                        pidfile, strerror(errno));
                return;
        }
        while(count < strlen(pidbuf)) {
                ssize_t r = write(fd, pidbuf+count, strlen(pidbuf)-count);
                if(r == -1) {
                        if(errno == EAGAIN || errno == EINTR)
                                continue;
                        log_err("cannot write to pidfile %s: %s",
                                pidfile, strerror(errno));
                        close(fd);
                        return;
                } else if(r == 0) {
                        log_err("cannot write any bytes to pidfile %s: "
                                "write returns 0 bytes written", pidfile);
                        close(fd);
                        return;
                }
                count += r;
        }
        close(fd);
}

/**
 * check old pid file.
 * @param pidfile: the file name of the pid file.
 * @param inchroot: if pidfile is inchroot and we can thus expect to
 *      be able to delete it.
 */
static void
checkoldpid(char* pidfile, int inchroot)
{
        pid_t old;
        if((old = readpid(pidfile)) != -1) {
                /* see if it is still alive */
                if(kill(old, 0) == 0 || errno == EPERM)
                        log_warn("unbound is already running as pid %u.", 
                                (unsigned)old);
                else    if(inchroot)
                        log_warn("did not exit gracefully last time (%u)", 
                                (unsigned)old);
        }
}
#endif /* HAVE_KILL */

/** detach from command line */
static void
detach(void)
{
#if defined(HAVE_DAEMON) && !defined(DEPRECATED_DAEMON)
        /* use POSIX daemon(3) function */
        if(daemon(1, 0) != 0)
                fatal_exit("daemon failed: %s", strerror(errno));
#else /* no HAVE_DAEMON */
#ifdef HAVE_FORK
        int fd;
        /* Take off... */
        switch (fork()) {
                case 0:
                        break;
                case -1:
                        fatal_exit("fork failed: %s", strerror(errno));
                default:
                        /* exit interactive session */
                        exit(0);
        }
        /* detach */
#ifdef HAVE_SETSID
        if(setsid() == -1)
                fatal_exit("setsid() failed: %s", strerror(errno));
#endif
        if ((fd = open("/dev/null", O_RDWR, 0)) != -1) {
                (void)dup2(fd, STDIN_FILENO);
                (void)dup2(fd, STDOUT_FILENO);
                (void)dup2(fd, STDERR_FILENO);
                if (fd > 2)
                        (void)close(fd);
        }
#endif /* HAVE_FORK */
#endif /* HAVE_DAEMON */
}

/** setup the remote and ticket keys */
static void
setup_sslctx_remote(struct daemon* daemon, struct config_file* cfg)
{
#ifdef HAVE_SSL
        if(!(daemon->rc = daemon_remote_create(cfg)))
                fatal_exit("could not set up remote-control");
#else /* HAVE_SSL */
        (void)daemon;(void)cfg;
#endif /* HAVE_SSL */
}

/** daemonize, drop user privileges and chroot if needed */
static void
perform_setup(struct daemon* daemon, struct config_file* cfg, int debug_mode,
        const char** cfgfile, int need_pidfile)
{
#ifdef HAVE_KILL
        int pidinchroot;
#endif
#ifdef HAVE_GETPWNAM
        struct passwd *pwd = NULL;
#endif

        if(!daemon_privileged(daemon))
                fatal_exit("could not do privileged setup");
#ifdef HAVE_GETPWNAM
        if(cfg->username && cfg->username[0]) {
                if((pwd = getpwnam(cfg->username)) == NULL)
                        fatal_exit("user '%s' does not exist.", cfg->username);
                /* endpwent below, in case we need pwd for setusercontext */
        }
#endif
#ifdef UB_ON_WINDOWS
        w_config_adjust_directory(cfg);
#endif

        /* read ssl keys while superuser and outside chroot */
        setup_sslctx_remote(daemon, cfg);
        daemon_setup_sslctxs(daemon, cfg);

        /* init syslog (as root) if needed, before daemonize, otherwise
         * a fork error could not be printed since daemonize closed stderr.*/
        if(cfg->use_syslog) {
                log_init(cfg->logfile, cfg->use_syslog, cfg->chrootdir);
        }
        /* if using a logfile, we cannot open it because the logfile would
         * be created with the wrong permissions, we cannot chown it because
         * we cannot chown system logfiles, so we do not open at all.
         * So, using a logfile, the user does not see errors unless -d is
         * given to unbound on the commandline. */

#ifdef HAVE_KILL
        /* true if pidfile is inside chrootdir, or nochroot */
        pidinchroot = need_pidfile && (!(cfg->chrootdir && cfg->chrootdir[0]) ||
                                (cfg->chrootdir && cfg->chrootdir[0] &&
                                strncmp(cfg->pidfile, cfg->chrootdir,
                                strlen(cfg->chrootdir))==0));

        /* check old pid file before forking */
        if(cfg->pidfile && cfg->pidfile[0] && need_pidfile) {
                /* calculate position of pidfile */
                if(cfg->pidfile[0] == '/')
                        daemon->pidfile = strdup(cfg->pidfile);
                else    daemon->pidfile = fname_after_chroot(cfg->pidfile, 
                                cfg, 1);
                if(!daemon->pidfile)
                        fatal_exit("pidfile alloc: out of memory");
                /* Check old pid if there is no username configured.
                 * With a username, the assumption is that the privilege
                 * drop makes a pidfile not removed when the server stopped
                 * last time. The server does not chown the pidfile for it,
                 * because that creates privilege escape problems, with the
                 * pidfile writable by unprivileged users, but used by
                 * privileged users. */
                if(!(cfg->username && cfg->username[0]))
                        checkoldpid(daemon->pidfile, pidinchroot);
        }
#endif

        /* daemonize because pid is needed by the writepid func */
        if(!debug_mode && cfg->do_daemonize) {
                detach();
        }

        /* write new pidfile (while still root, so can be outside chroot) */
#ifdef HAVE_KILL
        if(cfg->pidfile && cfg->pidfile[0] && need_pidfile) {
                writepid(daemon->pidfile, getpid());
        }
#else
        (void)daemon;
        (void)need_pidfile;
#endif /* HAVE_KILL */

        /* Set user context */
#ifdef HAVE_GETPWNAM
        if(cfg->username && cfg->username[0] && cfg_uid != (uid_t)-1) {
#ifdef HAVE_SETUSERCONTEXT
                /* setusercontext does initgroups, setuid, setgid, and
                 * also resource limits from login config, but we
                 * still call setresuid, setresgid to be sure to set all uid*/
                if(setusercontext(NULL, pwd, cfg_uid, (unsigned)
                        LOGIN_SETALL & ~LOGIN_SETUSER & ~LOGIN_SETGROUP) != 0)
                        log_warn("unable to setusercontext %s: %s",
                                cfg->username, strerror(errno));
#else
                (void)pwd;
#endif /* HAVE_SETUSERCONTEXT */
        }
#endif /* HAVE_GETPWNAM */

        /* box into the chroot */
#ifdef HAVE_CHROOT
        if(cfg->chrootdir && cfg->chrootdir[0]) {
                if(chdir(cfg->chrootdir)) {
                        fatal_exit("unable to chdir to chroot %s: %s",
                                cfg->chrootdir, strerror(errno));
                }
                verbose(VERB_QUERY, "chdir to %s", cfg->chrootdir);
                if(chroot(cfg->chrootdir))
                        fatal_exit("unable to chroot to %s: %s", 
                                cfg->chrootdir, strerror(errno));
                if(chdir("/"))
                        fatal_exit("unable to chdir to / in chroot %s: %s",
                                cfg->chrootdir, strerror(errno));
                verbose(VERB_QUERY, "chroot to %s", cfg->chrootdir);
                if(strncmp(*cfgfile, cfg->chrootdir, 
                        strlen(cfg->chrootdir)) == 0) 
                        (*cfgfile) += strlen(cfg->chrootdir);

                /* adjust stored pidfile for chroot */
                if(daemon->pidfile && daemon->pidfile[0] && 
                        strncmp(daemon->pidfile, cfg->chrootdir,
                        strlen(cfg->chrootdir))==0) {
                        char* old = daemon->pidfile;
                        daemon->pidfile = strdup(old+strlen(cfg->chrootdir));
                        free(old);
                        if(!daemon->pidfile)
                                log_err("out of memory in pidfile adjust");
                }
                daemon->chroot = strdup(cfg->chrootdir);
                if(!daemon->chroot)
                        log_err("out of memory in daemon chroot dir storage");
        }
#else
        (void)cfgfile;
#endif
        /* change to working directory inside chroot */
        if(cfg->directory && cfg->directory[0]) {
                char* dir = cfg->directory;
                if(cfg->chrootdir && cfg->chrootdir[0] &&
                        strncmp(dir, cfg->chrootdir, 
                        strlen(cfg->chrootdir)) == 0)
                        dir += strlen(cfg->chrootdir);
                if(dir[0]) {
                        if(chdir(dir)) {
                                fatal_exit("Could not chdir to %s: %s",
                                        dir, strerror(errno));
                        }
                        verbose(VERB_QUERY, "chdir to %s", dir);
                }
        }

        /* drop permissions after chroot, getpwnam, pidfile, syslog done*/
#ifdef HAVE_GETPWNAM
        if(cfg->username && cfg->username[0] && cfg_uid != (uid_t)-1) {
#  ifdef HAVE_INITGROUPS
                if(initgroups(cfg->username, cfg_gid) != 0)
                        log_warn("unable to initgroups %s: %s",
                                cfg->username, strerror(errno));
#  endif /* HAVE_INITGROUPS */
#  ifdef HAVE_ENDPWENT
                endpwent();
#  endif

#ifdef HAVE_SETRESGID
                if(setresgid(cfg_gid,cfg_gid,cfg_gid) != 0)
#elif defined(HAVE_SETREGID) && !defined(DARWIN_BROKEN_SETREUID)
                if(setregid(cfg_gid,cfg_gid) != 0)
#else /* use setgid */
                if(setgid(cfg_gid) != 0)
#endif /* HAVE_SETRESGID */
                        fatal_exit("unable to set group id of %s: %s", 
                                cfg->username, strerror(errno));
#ifdef HAVE_SETRESUID
                if(setresuid(cfg_uid,cfg_uid,cfg_uid) != 0)
#elif defined(HAVE_SETREUID) && !defined(DARWIN_BROKEN_SETREUID)
                if(setreuid(cfg_uid,cfg_uid) != 0)
#else /* use setuid */
                if(setuid(cfg_uid) != 0)
#endif /* HAVE_SETRESUID */
                        fatal_exit("unable to set user id of %s: %s", 
                                cfg->username, strerror(errno));
                verbose(VERB_QUERY, "drop user privileges, run as %s", 
                        cfg->username);
        }
#endif /* HAVE_GETPWNAM */
        /* file logging inited after chroot,chdir,setuid is done so that 
         * it would succeed on SIGHUP as well */
        if(!cfg->use_syslog)
                log_init(cfg->logfile, cfg->use_syslog, cfg->chrootdir);
        daemon->cfgfile = strdup(*cfgfile);
        if(!daemon->cfgfile)
                fatal_exit("out of memory in daemon cfgfile strdup");
}

/**
 * Run the daemon. 
 * @param cfgfile: the config file name.
 * @param cmdline_verbose: verbosity resulting from commandline -v.
 *    These increase verbosity as specified in the config file.
 * @param debug_mode: if set, do not daemonize.
 * @param need_pidfile: if false, no pidfile is checked or created.
 */
static void 
run_daemon(const char* cfgfile, int cmdline_verbose, int debug_mode, int need_pidfile)
{
        struct config_file* cfg = NULL;
        struct daemon* daemon = NULL;
        int done_setup = 0;

        if(!(daemon = daemon_init()))
                fatal_exit("alloc failure");
        while(!daemon->need_to_exit) {
                if(done_setup)
                        verbose(VERB_OPS, "Restart of %s.", PACKAGE_STRING);
                else    verbose(VERB_OPS, "Start of %s.", PACKAGE_STRING);

                /* config stuff */
                if(!(cfg = config_create()))
                        fatal_exit("Could not alloc config defaults");
                if(!config_read(cfg, cfgfile, daemon->chroot)) {
                        if(errno != ENOENT)
                                fatal_exit("Could not read config file: %s."
                                        " Maybe try unbound -dd, it stays on "
                                        "the commandline to see more errors, "
                                        "or unbound-checkconf", cfgfile);
                        log_warn("Continuing with default config settings");
                        config_auto_slab_values(cfg);
                }
                apply_settings(daemon, cfg, cmdline_verbose, debug_mode);
                if(!done_setup)
                        config_lookup_uid(cfg);
        
                /* prepare */
                if(!daemon_open_shared_ports(daemon))
                        fatal_exit("could not open ports");
                if(!done_setup) { 
                        perform_setup(daemon, cfg, debug_mode, &cfgfile, need_pidfile);
                        done_setup = 1; 
                } else {
                        /* reopen log after HUP to facilitate log rotation */
                        if(!cfg->use_syslog)
                                log_init(cfg->logfile, 0, cfg->chrootdir);
                }
                /* work */
                daemon_fork(daemon);

                /* clean up for restart */
                verbose(VERB_ALGO, "cleanup.");
                daemon_cleanup(daemon);
                config_delete(cfg);
        }
        verbose(VERB_ALGO, "Exit cleanup.");
        /* this unlink may not work if the pidfile is located outside
         * of the chroot/workdir or we no longer have permissions */
        if(daemon->pidfile) {
                int fd;
                /* truncate pidfile */
                fd = open(daemon->pidfile, O_WRONLY | O_TRUNC
#ifdef O_NOFOLLOW
                        | O_NOFOLLOW
#endif
                        , 0644);
                if(fd != -1)
                        close(fd);
                /* delete pidfile */
                unlink(daemon->pidfile);
        }
        daemon_delete(daemon);
}

/** getopt global, in case header files fail to declare it. */
extern int optind;
/** getopt global, in case header files fail to declare it. */
extern char* optarg;

/**
 * main program. Set options given commandline arguments.
 * @param argc: number of commandline arguments.
 * @param argv: array of commandline arguments.
 * @return: exit status of the program.
 */
int 
main(int argc, char* argv[])
{
        int c;
        const char* cfgfile = CONFIGFILE;
        const char* winopt = NULL;
        const char* log_ident_default;
        int cmdline_verbose = 0;
        int debug_mode = 0;
        int need_pidfile = 1;

#ifdef UB_ON_WINDOWS
        int cmdline_cfg = 0;
#endif

        checklock_start();
        log_init(NULL, 0, NULL);
        log_ident_default = strrchr(argv[0],'/')?strrchr(argv[0],'/')+1:argv[0];
        log_ident_set_default(log_ident_default);
        log_ident_set(log_ident_default);
        /* parse the options */
        while( (c=getopt(argc, argv, "c:dhpvw:V")) != -1) {
                switch(c) {
                case 'c':
                        cfgfile = optarg;
#ifdef UB_ON_WINDOWS
                        cmdline_cfg = 1;
#endif
                        break;
                case 'v':
                        cmdline_verbose++;
                        verbosity++;
                        break;
                case 'p':
                        need_pidfile = 0;
                        break;
                case 'd':
                        debug_mode++;
                        break;
                case 'w':
                        winopt = optarg;
                        break;
                case 'V':
                        print_build_options();
                        return 0;
                case '?':
                case 'h':
                default:
                        usage();
                        return 1;
                }
        }
        argc -= optind;
        /* argv += optind; not using further arguments */

        if(winopt) {
#ifdef UB_ON_WINDOWS
                wsvc_command_option(winopt, cfgfile, cmdline_verbose, 
                        cmdline_cfg);
#else
                fatal_exit("option not supported");
#endif
        }

        if(argc != 0) {
                usage();
                return 1;
        }

        run_daemon(cfgfile, cmdline_verbose, debug_mode, need_pidfile);
        log_init(NULL, 0, NULL); /* close logfile */
#ifndef unbound_testbound
        if(log_get_lock()) {
                lock_basic_destroy((lock_basic_type*)log_get_lock());
        }
#endif
        return 0;
}