unbound/daemon/unbound.c
Wouter Wijngaards 95f5b577d4 and include...
git-svn-id: file:///svn/unbound/trunk@1476 be551aaa-1e26-0410-a405-d3ace91eadb9
2009-02-12 09:02:12 +00:00

633 lines
18 KiB
C

/*
* 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 REGENTS 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"
#include "util/log.h"
#include "daemon/daemon.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/data/msgreply.h"
#include "util/module.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
#ifdef HAVE_SYS_RESOURCE_H
#include <sys/resource.h>
#endif
#ifdef HAVE_LOGIN_CAP_H
#include <login_cap.h>
#endif
#ifdef USE_MINI_EVENT
# ifdef USE_WINSOCK
# include "util/winsock_event.h"
# else
# include "util/mini_event.h"
# endif
#else
# include <event.h>
#endif
/** global debug value to keep track of heap memory allocation */
void* unbound_start_brk = 0;
/** print usage. */
static void usage()
{
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");
printf("Version %s\n", PACKAGE_VERSION);
printf("libevent %s, libldns %s, %s\n",
event_get_version(), ldns_version(),
SSLeay_version(SSLEAY_VERSION));
printf("BSD licensed, see LICENSE in source package for details.\n");
printf("Report bugs to %s\n", PACKAGE_BUGREPORT);
}
/** check file descriptor count */
static void
checkrlimits(struct config_file* cfg)
{
#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;
#endif
size_t total = numthread * perthread + misc;
size_t avail;
struct rlimit rlim;
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);
if(setrlimit(RLIMIT_NOFILE, &rlim) < 0) {
log_warn("setrlimit: %s", strerror(errno));
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);
}
if(total > 1024 &&
strncmp(event_get_version(), "mini-event", 10) == 0) {
log_err("too many file descriptors requested. The builtin"
"mini-event cannot handle more than 1024. Config "
"for less fds or compile with libevent");
fatal_exit("configuration needs too many file descriptors");
}
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 or compile with "
" libevent");
fatal_exit("configuration needs too many file descriptors");
}
#else
(void)cfg;
#endif /* HAVE_GETRLIMIT */
}
/** 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 */
daemon->cfg = cfg;
verbosity = cmdline_verbose + cfg->verbosity;
config_apply(cfg);
if(!daemon->env->msg_cache ||
cfg->msg_cache_size != slabhash_get_size(daemon->env->msg_cache) ||
cfg->msg_cache_slabs != daemon->env->msg_cache->size) {
slabhash_delete(daemon->env->msg_cache);
daemon->env->msg_cache = slabhash_create(cfg->msg_cache_slabs,
HASH_DEFAULT_STARTARRAY, cfg->msg_cache_size,
msgreply_sizefunc, query_info_compare,
query_entry_delete, reply_info_delete, NULL);
if(!daemon->env->msg_cache) {
fatal_exit("malloc failure updating config settings");
}
}
if((daemon->env->rrset_cache = rrset_cache_adjust(
daemon->env->rrset_cache, cfg, &daemon->superalloc)) == 0)
fatal_exit("malloc failure updating config settings");
if((daemon->env->infra_cache = infra_adjust(daemon->env->infra_cache,
cfg))==0)
fatal_exit("malloc failure updating config settings");
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)
{
#ifdef HAVE_DAEMON
/* use POSIX daemon(3) function */
if(daemon(1, 0) != 0)
fatal_exit("daemon failed: %s", strerror(errno));
#else /* no HAVE_DAEMON */
#ifdef HAVE_WORKING_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_WORKING_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. */
#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) {
fatal_exit("cannot chown %u.%u %s: %s",
(unsigned)uid, (unsigned)gid,
daemon->pidfile, strerror(errno));
}
}
}
}
#else
(void)daemon;
#endif
/* 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));
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_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, LOGIN_SETALL) != 0)
log_warn("unable to setusercontext %s: %s",
cfg->username, strerror(errno));
#else /* !HAVE_SETUSERCONTEXT */
# ifdef HAVE_INITGROUPS
if(initgroups(cfg->username, gid) != 0)
log_warn("unable to initgroups %s: %s",
cfg->username, strerror(errno));
# endif /* HAVE_INITGROUPS */
#endif /* HAVE_SETUSERCONTEXT */
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;
int cmdline_verbose = 0;
int debug_mode = 0;
#ifdef HAVE_SBRK
/* take debug snapshot of heap */
unbound_start_brk = sbrk(0);
#endif
log_init(NULL, 0, NULL);
/* parse the options */
while( (c=getopt(argc, argv, "c:dhv")) != -1) {
switch(c) {
case 'c':
cfgfile = optarg;
break;
case 'v':
cmdline_verbose ++;
verbosity++;
break;
case 'd':
debug_mode = 1;
break;
case '?':
case 'h':
default:
usage();
return 1;
}
}
argc -= optind;
argv += optind;
if(argc != 0) {
usage();
return 1;
}
run_daemon(cfgfile, cmdline_verbose, debug_mode);
log_init(NULL, 0, NULL); /* close logfile */
return 0;
}