/* * 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 #endif #include #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 #include #include #ifdef HAVE_PWD_H #include #endif #ifdef HAVE_GRP_H #include #endif #ifndef S_SPLINT_S /* splint chokes on this system header file */ #ifdef HAVE_SYS_RESOURCE_H #include #endif #endif /* S_SPLINT_S */ #ifdef HAVE_LOGIN_CAP_H #include #endif #ifdef USE_MINI_EVENT # ifdef USE_WINSOCK # include "util/winsock_event.h" # else # include "util/mini_event.h" # endif #else # include #endif #ifdef UB_ON_WINDOWS # include "winrc/win_svc.h" #endif #ifdef HAVE_NSS /* nss3 */ # include "nss.h" #endif #ifdef HAVE_SBRK /** global debug value to keep track of heap memory allocation */ void* unbound_start_brk = 0; #endif #if !defined(HAVE_EVENT_BASE_GET_METHOD) && (defined(HAVE_EV_LOOP) || defined(HAVE_EV_DEFAULT_LOOP)) static const char* ev_backend2str(int b) { switch(b) { case EVBACKEND_SELECT: return "select"; case EVBACKEND_POLL: return "poll"; case EVBACKEND_EPOLL: return "epoll"; case EVBACKEND_KQUEUE: return "kqueue"; case EVBACKEND_DEVPOLL: return "devpoll"; case EVBACKEND_PORT: return "evport"; } return "unknown"; } #endif /** get the event system in use */ static void get_event_sys(const char** n, const char** s, const char** m) { #ifdef USE_WINSOCK *n = "event"; *s = "winsock"; *m = "WSAWaitForMultipleEvents"; #elif defined(USE_MINI_EVENT) *n = "mini-event"; *s = "internal"; *m = "select"; #else struct event_base* b; *s = event_get_version(); # ifdef HAVE_EVENT_BASE_GET_METHOD *n = "libevent"; b = event_base_new(); *m = event_base_get_method(b); # elif defined(HAVE_EV_LOOP) || defined(HAVE_EV_DEFAULT_LOOP) *n = "libev"; b = (struct event_base*)ev_default_loop(EVFLAG_AUTO); *m = ev_backend2str(ev_backend((struct ev_loop*)b)); # else *n = "unknown"; *m = "not obtainable"; b = NULL; # endif # ifdef HAVE_EVENT_BASE_FREE event_base_free(b); # endif #endif } /** print usage. */ static void usage() { const char** m; const char *evnm="event", *evsys="", *evmethod=""; 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("-v verbose (more times to increase verbosity)\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("Version %s\n", PACKAGE_VERSION); get_event_sys(&evnm, &evsys, &evmethod); printf("linked libs: %s %s (it uses %s), %s\n", evnm, evsys, evmethod, #ifdef HAVE_SSL SSLeay_version(SSLEAY_VERSION) #elif defined(HAVE_NSS) NSS_GetVersion() #endif ); printf("linked modules:"); for(m = module_list_avail(); *m; m++) printf(" %s", *m); printf("\n"); 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 #ifdef HAVE_GETRLIMIT /* 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; if(total > 1024 && strncmp(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(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)); #else if(1) { #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; } log_warn("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) { /* apply if they have changed */ verbosity = cmdline_verbose + cfg->verbosity; daemon_apply_cfg(daemon, cfg); checkrlimits(cfg); } #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) { FILE* f; if ((f = fopen(pidfile, "w")) == NULL ) { log_err("cannot open pidfile %s: %s", pidfile, strerror(errno)); return; } if(fprintf(f, "%lu\n", (unsigned long)pid) < 0) { log_err("cannot write to pidfile %s: %s", pidfile, strerror(errno)); } fclose(f); } /** * 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 */ } /** daemonize, drop user priviliges and chroot if needed */ static void perform_setup(struct daemon* daemon, struct config_file* cfg, int debug_mode, const char** cfgfile) { #ifdef HAVE_GETPWNAM struct passwd *pwd = NULL; uid_t uid; gid_t gid; /* initialize, but not to 0 (root) */ memset(&uid, 112, sizeof(uid)); memset(&gid, 112, sizeof(gid)); log_assert(cfg); if(cfg->username && cfg->username[0]) { if((pwd = getpwnam(cfg->username)) == NULL) fatal_exit("user '%s' does not exist.", cfg->username); uid = pwd->pw_uid; gid = pwd->pw_gid; /* endpwent below, in case we need pwd for setusercontext */ } #endif /* 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. */ /* read ssl keys while superuser and outside chroot */ #ifdef HAVE_SSL if(!(daemon->rc = daemon_remote_create(cfg))) fatal_exit("could not set up remote-control"); if(cfg->ssl_service_key && cfg->ssl_service_key[0]) { if(!(daemon->listen_sslctx = listen_sslctx_create( cfg->ssl_service_key, cfg->ssl_service_pem, NULL))) fatal_exit("could not set up listen SSL_CTX"); } if(!(daemon->connect_sslctx = connect_sslctx_create(NULL, NULL, NULL))) fatal_exit("could not set up connect SSL_CTX"); #endif #ifdef HAVE_KILL /* check old pid file before forking */ if(cfg->pidfile && cfg->pidfile[0]) { /* 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"); checkoldpid(daemon->pidfile, /* true if pidfile is inside chrootdir, or nochroot */ !(cfg->chrootdir && cfg->chrootdir[0]) || (cfg->chrootdir && cfg->chrootdir[0] && strncmp(daemon->pidfile, cfg->chrootdir, strlen(cfg->chrootdir))==0)); } #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]) { writepid(daemon->pidfile, getpid()); if(!(cfg->chrootdir && cfg->chrootdir[0]) || (cfg->chrootdir && cfg->chrootdir[0] && strncmp(daemon->pidfile, cfg->chrootdir, strlen(cfg->chrootdir))==0)) { /* delete of pidfile could potentially work, * chown to get permissions */ if(cfg->username && cfg->username[0]) { if(chown(daemon->pidfile, uid, gid) == -1) { log_err("cannot chown %u.%u %s: %s", (unsigned)uid, (unsigned)gid, daemon->pidfile, strerror(errno)); } } } } #else (void)daemon; #endif /* Set user context */ #ifdef HAVE_GETPWNAM if(cfg->username && cfg->username[0]) { #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, uid, (unsigned) LOGIN_SETALL & ~LOGIN_SETUSER & ~LOGIN_SETGROUP) != 0) log_warn("unable to setusercontext %s: %s", cfg->username, strerror(errno)); #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]) { # ifdef HAVE_INITGROUPS if(initgroups(cfg->username, gid) != 0) log_warn("unable to initgroups %s: %s", cfg->username, strerror(errno)); # endif /* HAVE_INITGROUPS */ endpwent(); #ifdef HAVE_SETRESGID if(setresgid(gid,gid,gid) != 0) #elif defined(HAVE_SETREGID) && !defined(DARWIN_BROKEN_SETREUID) if(setregid(gid,gid) != 0) #else /* use setgid */ if(setgid(gid) != 0) #endif /* HAVE_SETRESGID */ fatal_exit("unable to set group id of %s: %s", cfg->username, strerror(errno)); #ifdef HAVE_SETRESUID if(setresuid(uid,uid,uid) != 0) #elif defined(HAVE_SETREUID) && !defined(DARWIN_BROKEN_SETREUID) if(setreuid(uid,uid) != 0) #else /* use setuid */ if(setuid(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); } /** * 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. */ static void run_daemon(const char* cfgfile, int cmdline_verbose, int debug_mode) { 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", cfgfile); log_warn("Continuing with default config settings"); } apply_settings(daemon, cfg, cmdline_verbose); /* prepare */ if(!daemon_open_shared_ports(daemon)) fatal_exit("could not open ports"); if(!done_setup) { perform_setup(daemon, cfg, debug_mode, &cfgfile); 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, 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; int cmdline_verbose = 0; int debug_mode = 0; #ifdef UB_ON_WINDOWS int cmdline_cfg = 0; #endif #ifdef HAVE_SBRK /* take debug snapshot of heap */ unbound_start_brk = sbrk(0); #endif log_init(NULL, 0, NULL); log_ident_set(strrchr(argv[0],'/')?strrchr(argv[0],'/')+1:argv[0]); /* parse the options */ while( (c=getopt(argc, argv, "c:dhvw:")) != -1) { switch(c) { case 'c': cfgfile = optarg; #ifdef UB_ON_WINDOWS cmdline_cfg = 1; #endif break; case 'v': cmdline_verbose ++; verbosity++; break; case 'd': debug_mode = 1; break; case 'w': winopt = optarg; break; case '?': case 'h': default: usage(); return 1; } } argc -= optind; argv += optind; 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); log_init(NULL, 0, NULL); /* close logfile */ return 0; }