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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "sd-daemon.h"
#include "sd-event.h"
#include "bus-log-control-api.h"
#include "capability-util.h"
#include "daemon-util.h"
#include "main-func.h"
#include "mkdir-label.h"
#include "resolved-bus.h"
#include "resolved-conf.h"
#include "resolved-manager.h"
#include "resolved-resolv-conf.h"
#include "selinux-util.h"
#include "service-util.h"
#include "signal-util.h"
#include "user-util.h"
static int run(int argc, char *argv[]) {
_cleanup_(manager_freep) Manager *m = NULL;
_unused_ _cleanup_(notify_on_cleanup) const char *notify_stop = NULL;
int r;
log_setup();
r = service_parse_argv("systemd-resolved.service",
"Provide name resolution with caching using DNS, mDNS, LLMNR.",
BUS_IMPLEMENTATIONS(&manager_object,
&log_control_object),
argc, argv);
if (r <= 0)
return r;
umask(0022);
r = mac_selinux_init();
if (r < 0)
return r;
/* Drop privileges, but only if we have been started as root. If we are not running as root we assume most
* privileges are already dropped and we can't create our directory. */
if (getuid() == 0) {
const char *user = "systemd-resolve";
uid_t uid;
gid_t gid;
r = get_user_creds(&user, &uid, &gid, NULL, NULL, 0);
if (r < 0)
return log_error_errno(r, "Cannot resolve user name %s: %m", user);
/* As we're root, we can create the directory where resolv.conf will live */
r = mkdir_safe_label("/run/systemd/resolve", 0755, uid, gid, MKDIR_WARN_MODE);
if (r < 0)
return log_error_errno(r, "Could not create runtime directory: %m");
/* Drop privileges, but keep three caps. Note that we drop two of those too, later on (see below) */
r = drop_privileges(uid, gid,
(UINT64_C(1) << CAP_NET_RAW)| /* needed for SO_BINDTODEVICE */
(UINT64_C(1) << CAP_NET_BIND_SERVICE)| /* needed to bind on port 53 */
(UINT64_C(1) << CAP_SETPCAP) /* needed in order to drop the caps later */);
if (r < 0)
return log_error_errno(r, "Failed to drop privileges: %m");
}
assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGTERM, SIGINT, SIGUSR1, SIGUSR2, SIGRTMIN+1, -1) >= 0);
r = manager_new(&m);
if (r < 0)
return log_error_errno(r, "Could not create manager: %m");
r = manager_start(m);
if (r < 0)
return log_error_errno(r, "Failed to start manager: %m");
/* Write finish default resolv.conf to avoid a dangling symlink */
(void) manager_write_resolv_conf(m);
(void) manager_check_resolv_conf(m);
/* Let's drop the remaining caps now */
r = capability_bounding_set_drop((UINT64_C(1) << CAP_NET_RAW), true);
if (r < 0)
return log_error_errno(r, "Failed to drop remaining caps: %m");
notify_stop = notify_start(NOTIFY_READY, NOTIFY_STOPPING);
r = sd_event_loop(m->event);
if (r < 0)
return log_error_errno(r, "Event loop failed: %m");
return 0;
}
DEFINE_MAIN_FUNCTION(run);
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