int main (int argc, char **argv)
{
int i;
int cachesize = CACHESIZ;
int port = NAMESERVER_PORT;
unsigned int options;
int first_loop = 1;
#ifdef HAVE_FILE_SYSTEM
int logged_resolv = 0, logged_lease = 0;
char *resolv = RESOLVFILE;
char *runfile = RUNFILE;
time_t resolv_changed = 0;
char *lease_file = NULL;
off_t lease_file_size = (off_t)0;
ino_t lease_file_inode = (ino_t)0;
#endif
struct irec *iface;
int peerfd, peerfd6;
struct irec *interfaces = NULL;
char *mxname = NULL;
char *mxtarget = NULL;
char *domain_suffix = NULL;
char *username = CHUSER;
struct iname *if_names = NULL;
struct iname *if_addrs = NULL;
struct server *serv_addrs = NULL;
char *dnamebuff, *packet;
struct server *servers, *last_server;
sighup = 1; /* init cache the first time through */
sigusr1 = 0; /* but don't dump */
signal(SIGUSR1, sig_handler);
signal(SIGHUP, sig_handler);
/* These get allocated here to avoid overflowing the small stack
on embedded systems. dnamebuff is big enough to hold one
maximal sixed domain name and gets passed into all the processing
code. We manage to get away with one buffer. */
dnamebuff = safe_malloc(MAXDNAME);
/* Size: we check after adding each record, so there must be
memory for the largest packet, and the largest record */
packet = safe_malloc(PACKETSZ+MAXDNAME+RRFIXEDSZ);
#ifdef HAVE_FILE_SYSTEM
options = read_opts(argc, argv, dnamebuff, &resolv, &mxname, &mxtarget, &lease_file,
&username, &domain_suffix, &runfile, &if_names, &if_addrs,
&serv_addrs, &cachesize, &port) ;
#else
options = read_opts(argc, argv, dnamebuff, NULL, &mxname, &mxtarget, NULL,
&username, &domain_suffix, NULL, &if_names, &if_addrs,
&serv_addrs, &cachesize, &port) ;
#endif
/* peerfd is not bound to a low port
so that we can send queries out on it without them getting
blocked at firewalls */
if ((peerfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1 &&
errno != EAFNOSUPPORT &&
errno != EINVAL)
die("dnsmasq: cannot create socket: %s", NULL);
#ifdef HAVE_IPV6
if ((peerfd6 = socket(AF_INET6, SOCK_DGRAM, 0)) == -1 &&
errno != EAFNOSUPPORT &&
errno != EINVAL)
die("dnsmasq: cannot create IPv6 socket: %s", NULL);
#else
peerfd6 = -1;
#endif
if (peerfd == -1 && peerfd6 == -1)
die("dnsmasq: no kernel support for IPv4 _or_ IPv6.", NULL);
interfaces = find_all_interfaces(if_names, if_addrs, port);
/* open a socket bound to NS port on each local interface.
this is necessary to ensure that our replies originate from
the address they were sent to. See Stevens page 531 */
for (iface = interfaces; iface; iface = iface->next)
{
if ((iface->fd = socket(iface->addr.sa.sa_family, SOCK_DGRAM, 0)) == -1)
die("cannot create socket: %s", NULL);
if (bind(iface->fd, &iface->addr.sa, sa_len(&iface->addr)))
die("bind failed: %s", NULL);
}
forward_init(1);
cache_init(cachesize, options & OPT_LOG);
setbuf(stdout, NULL);
#ifdef HAVE_FILE_SYSTEM
if (!(options & OPT_DEBUG))
{
FILE *pidfile;
struct passwd *ent_pw;
/* The following code "daemonizes" the process.
See Stevens section 12.4 */
#ifdef HAVE_FORK
if (fork() != 0 )
exit(0);
setsid();
if (fork() != 0)
exit(0);
#endif
chdir("/");
umask(022); /* make pidfile 0644 */
/* write pidfile _after_ forking ! */
if (runfile && (pidfile = fopen(runfile, "w")))
{
fprintf(pidfile, "%d\n", (int) getpid());
fclose(pidfile);
}
umask(0);
for (i=0; i<64; i++)
{
if (i == peerfd || i == peerfd6)
continue;
for (iface = interfaces; iface; iface = iface->next)
if (iface->fd == i)
break;
if (!iface)
close(i);
}
/* Change uid and gid for security */
if (username && (ent_pw = getpwnam(username)))
{
gid_t dummy;
struct group *gp;
/* remove all supplimentary groups */
setgroups(0, &dummy);
/* change group to "dip" if it exists, for /etc/ppp/resolv.conf
otherwise get the group for "nobody" */
if ((gp = getgrnam("dip")) || (gp = getgrgid(ent_pw->pw_gid)))
setgid(gp->gr_gid);
/* finally drop root */
setuid(ent_pw->pw_uid);
}
}
#else
#endif
/* In debug mode, log to stderr too and cut the prefix crap. */
openlog("dnsmasq", options & OPT_DEBUG ? LOG_PERROR : LOG_PID, LOG_DAEMON);
if (cachesize)
syslog(LOG_INFO, "started, version %s cachesize %d", VERSION, cachesize);
else
syslog(LOG_INFO, "started, version %s cache disabled", VERSION);
if (mxname)
syslog(LOG_INFO, "serving MX record for mailhost %s target %s",
mxname, mxtarget);
if (getuid() == 0 || geteuid() == 0)
syslog(LOG_WARNING, "failed to drop root privs");
serv_addrs = servers = last_server = check_servers(serv_addrs, interfaces, peerfd, peerfd6);
while (1)
{
int ready, maxfd = peerfd > peerfd6 ? peerfd : peerfd6;
fd_set rset;
HEADER *header;
#ifdef HAVE_FILE_SYSTEM
struct stat statbuf;
#endif
if (first_loop)
/* do init stuff only first time round. */
{
first_loop = 0;
ready = 0;
}
else
{
FD_ZERO(&rset);
if (peerfd != -1)
FD_SET(peerfd, &rset);
if (peerfd6 != -1)
FD_SET(peerfd6, &rset);
for (iface = interfaces; iface; iface = iface->next)
{
FD_SET(iface->fd, &rset);
if (iface->fd > maxfd)
maxfd = iface->fd;
}
ready = select(maxfd+1, &rset, NULL, NULL, NULL);
if (ready == -1)
{
if (errno == EINTR)
ready = 0; /* do signal handlers */
else
continue;
}
}
#ifdef HAVE_FILE_SYSTEM
if (sighup)
{
signal(SIGHUP, SIG_IGN);
cache_reload(options & OPT_NO_HOSTS, dnamebuff);
if (resolv && (options & OPT_NO_POLL))
servers = last_server =
check_servers(reload_servers(resolv, dnamebuff, servers),
interfaces, peerfd, peerfd6);
sighup = 0;
signal(SIGHUP, sig_handler);
}
if (sigusr1)
{
signal(SIGUSR1, SIG_IGN);
dump_cache(options & (OPT_DEBUG | OPT_LOG), cachesize);
sigusr1 = 0;
signal(SIGUSR1, sig_handler);
}
if (resolv && !(options & OPT_NO_POLL))
{
if (stat(resolv, &statbuf) == -1)
{
if (!logged_resolv)
syslog(LOG_WARNING, "failed to access %s: %m", resolv);
logged_resolv = 1;
}
else
{
logged_resolv = 0;
if ((statbuf.st_mtime > resolv_changed) &&
(statbuf.st_mtime < time(NULL) || resolv_changed == 0))
{
resolv_changed = statbuf.st_mtime;
servers = last_server =
check_servers(reload_servers(resolv, dnamebuff, servers),
interfaces, peerfd, peerfd6);
}
}
}
#else
#endif
#ifdef HAVE_FILE_SYSTEM
if (lease_file)
{
if (stat(lease_file, &statbuf) == -1)
{
if (!logged_lease)
syslog(LOG_WARNING, "failed to access %s: %m", lease_file);
logged_lease = 1;
}
else
{
logged_lease = 0;
if ((lease_file_size == (off_t)0) ||
(statbuf.st_size > lease_file_size) ||
(statbuf.st_ino != lease_file_inode))
{
lease_file_size = statbuf.st_size;
lease_file_inode = statbuf.st_ino;
load_dhcp(lease_file, domain_suffix, time(NULL), dnamebuff);
}
}
}
#else
#endif
if (ready == 0)
continue; /* no sockets ready */
if (peerfd != -1 && FD_ISSET(peerfd, &rset))
last_server = reply_query(peerfd, packet, dnamebuff, last_server);
if (peerfd6 != -1 && FD_ISSET(peerfd6, &rset))
last_server = reply_query(peerfd6, packet, dnamebuff, last_server);
for (iface = interfaces; iface; iface = iface->next)
{
if (FD_ISSET(iface->fd, &rset))
{
/* request packet, deal with query */
union mysockaddr udpaddr;
socklen_t udplen = sizeof(udpaddr);
int m, n = recvfrom(iface->fd, packet, PACKETSZ, 0, &udpaddr.sa, &udplen);
udpaddr.sa.sa_family = iface->addr.sa.sa_family;
#ifdef HAVE_IPV6
if (udpaddr.sa.sa_family == AF_INET6)
udpaddr.in6.sin6_flowinfo = htonl(0);
#endif
header = (HEADER *)packet;
if (n >= (int)sizeof(HEADER) && !header->qr)
{
m = answer_request (header, ((char *) header) + PACKETSZ, (unsigned int)n,
mxname, mxtarget, options, dnamebuff);
if (m >= 1)
{
/* answered from cache, send reply */
sendto(iface->fd, (char *)header, m, 0,
&udpaddr.sa, sa_len(&udpaddr));
}
else
{
/* cannot answer from cache, send on to real nameserver */
last_server = forward_query(iface->fd, peerfd, peerfd6, &udpaddr, header, n,
options && OPT_ORDER, dnamebuff,
servers, last_server);
}
}
}
}
}
return 0;
}
static void
set_config_defaults (struct config *config)
{
long i;
char hostname[257];
int flags;
/* Default guest name is derived from the source hostname. If we
* assume that the p2v ISO gets its IP address and hostname from
* DHCP, then there is at better than average chance that
* gethostname will return the real hostname here. It's better than
* trying to fish around in the guest filesystem anyway.
*/
if (gethostname (hostname, sizeof hostname) == -1) {
perror ("gethostname");
/* Generate a simple random name. */
if (guestfs_int_random_string (hostname, 8) == -1) {
perror ("/dev/urandom");
exit (EXIT_FAILURE);
}
} else {
char *p;
/* If the hostname is an FQDN, truncate before the first dot. */
p = strchr (hostname, '.');
if (p && p > hostname)
*p = '\0';
}
config->guestname = strdup (hostname);
/* Defaults for #vcpus and memory are taken from the physical machine. */
i = sysconf (_SC_NPROCESSORS_ONLN);
if (i == -1) {
perror ("sysconf: _SC_NPROCESSORS_ONLN");
config->vcpus = 1;
}
else if (i == 0)
config->vcpus = 1;
else
config->vcpus = i;
i = sysconf (_SC_PHYS_PAGES);
if (i == -1) {
perror ("sysconf: _SC_PHYS_PAGES");
config->memory = 1024 * 1024 * 1024;
}
else
config->memory = i;
i = sysconf (_SC_PAGESIZE);
if (i == -1) {
perror ("sysconf: _SC_PAGESIZE");
config->memory *= 4096;
}
else
config->memory *= i;
/* Round up the default memory to a power of 2, since the kernel
* memory is not included in the total physical pages returned
* above.
* http://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2
*/
config->memory--;
config->memory |= config->memory >> 1;
config->memory |= config->memory >> 2;
config->memory |= config->memory >> 4;
config->memory |= config->memory >> 8;
config->memory |= config->memory >> 16;
config->memory |= config->memory >> 32;
config->memory++;
flags = cpuinfo_flags ();
if (flags >= 0)
config->flags = flags;
else
config->flags = 0;
find_all_disks ();
if (all_disks)
config->disks = guestfs_int_copy_string_list (all_disks);
if (all_removable)
config->removable = guestfs_int_copy_string_list (all_removable);
find_all_interfaces ();
if (all_interfaces)
config->interfaces = guestfs_int_copy_string_list (all_interfaces);
/* Default output drops the guest onto /var/tmp on the conversion
* server, a hopefully safe default.
*/
config->output = strdup ("local");
config->output_storage = strdup ("/var/tmp");
}