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/* SPDX-License-Identifier: LGPL-2.1+ */
#include "sd-daemon.h"
#include "sd-event.h"
#include "capability-util.h"
#include "mkdir.h"
#include "resolved-conf.h"
#include "resolved-manager.h"
#include "resolved-resolv-conf.h"
#include "selinux-util.h"
#include "signal-util.h"
#include "user-util.h"
int main(int argc, char *argv[]) {
_cleanup_(manager_freep) Manager *m = NULL;
const char *user = "systemd-resolve";
uid_t uid;
gid_t gid;
int r;
log_set_target(LOG_TARGET_AUTO);
log_parse_environment();
log_open();
if (argc != 1) {
log_error("This program takes no arguments.");
r = -EINVAL;
goto finish;
}
umask(0022);
r = mac_selinux_init();
if (r < 0) {
log_error_errno(r, "SELinux setup failed: %m");
goto finish;
}
r = get_user_creds(&user, &uid, &gid, NULL, NULL);
if (r < 0) {
log_error_errno(r, "Cannot resolve user name %s: %m", user);
goto finish;
}
/* Always create the directory where resolv.conf will live */
r = mkdir_safe_label("/run/systemd/resolve", 0755, uid, gid, MKDIR_WARN_MODE);
if (r < 0) {
log_error_errno(r, "Could not create runtime directory: %m");
goto finish;
}
/* Drop privileges, but only if we have been started as root. If we are not running as root we assume all
* privileges are already dropped. */
if (getuid() == 0) {
/* Drop privileges, but keep three caps. Note that we drop 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)
goto finish;
}
assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGTERM, SIGINT, SIGUSR1, SIGUSR2, SIGRTMIN+1, -1) >= 0);
r = manager_new(&m);
if (r < 0) {
log_error_errno(r, "Could not create manager: %m");
goto finish;
}
r = manager_start(m);
if (r < 0) {
log_error_errno(r, "Failed to start manager: %m");
goto finish;
}
/* 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(0, true);
if (r < 0) {
log_error_errno(r, "Failed to drop remaining caps: %m");
goto finish;
}
sd_notify(false,
"READY=1\n"
"STATUS=Processing requests...");
r = sd_event_loop(m->event);
if (r < 0) {
log_error_errno(r, "Event loop failed: %m");
goto finish;
}
sd_event_get_exit_code(m->event, &r);
finish:
sd_notify(false,
"STOPPING=1\n"
"STATUS=Shutting down...");
return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}
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