chiark / gitweb /
timesyncd: add sockaddr_pretty wrapper
[elogind.git] / src / timesync / timesyncd.c
index 6dcd942ec12fc968b644f19dcc4b7fb73d25632d..78ef5f72a1910f22f563f54a459b3a4ad9935281 100644 (file)
@@ -52,7 +52,9 @@
 #include "sd-network.h"
 #include "event-util.h"
 #include "network-util.h"
+#include "clock-util.h"
 #include "capability.h"
+#include "mkdir.h"
 #include "timesyncd.h"
 
 #define TIME_T_MAX (time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
@@ -150,6 +152,56 @@ static double square(double d) {
         return d * d;
 }
 
+static int load_clock_timestamp(uid_t uid, gid_t gid) {
+        _cleanup_close_ int fd = -1;
+        usec_t min = TIME_EPOCH * USEC_PER_SEC;
+        usec_t ct;
+        int r;
+
+        /* Let's try to make sure that the clock is always
+         * monotonically increasing, by saving the clock whenever we
+         * have a new NTP time, or when we shut down, and restoring it
+         * when we start again. This is particularly helpful on
+         * systems lacking a battery backed RTC. We also will adjust
+         * the time to at least the build time of systemd. */
+
+        fd = open("/var/lib/systemd/clock", O_RDWR|O_CLOEXEC, 0644);
+        if (fd >= 0) {
+                struct stat st;
+                usec_t stamp;
+
+                /* check if the recorded time is later than the compiled-in one */
+                r = fstat(fd, &st);
+                if (r >= 0) {
+                        stamp = timespec_load(&st.st_mtim);
+                        if (stamp > min)
+                                min = stamp;
+                }
+
+                /* Try to fix the access mode, so that we can still
+                   touch the file after dropping priviliges */
+                fchmod(fd, 0644);
+                fchown(fd, uid, gid);
+
+        } else
+                /* create stamp file with the compiled-in date */
+                touch_file("/var/lib/systemd/clock", true, min, uid, gid, 0644);
+
+        ct = now(CLOCK_REALTIME);
+        if (ct < min) {
+                struct timespec ts;
+                char date[FORMAT_TIMESTAMP_MAX];
+
+                log_info("System clock time unset or jumped backwards, restoring from recorded timestamp: %s",
+                         format_timestamp(date, sizeof(date), min));
+
+                if (clock_settime(CLOCK_REALTIME, timespec_store(&ts, min)) < 0)
+                        log_error("Failed to restore system clock: %m");
+        }
+
+        return 0;
+}
+
 static int manager_timeout(sd_event_source *source, usec_t usec, void *userdata) {
         _cleanup_free_ char *pretty = NULL;
         Manager *m = userdata;
@@ -158,7 +210,7 @@ static int manager_timeout(sd_event_source *source, usec_t usec, void *userdata)
         assert(m->current_server_name);
         assert(m->current_server_address);
 
-        sockaddr_pretty(&m->current_server_address->sockaddr.sa, m->current_server_address->socklen, true, &pretty);
+        server_address_pretty(m->current_server_address, &pretty);
         log_info("Timed out waiting for reply from %s (%s).", strna(pretty), m->current_server_name->string);
 
         return manager_connect(m);
@@ -198,7 +250,7 @@ static int manager_send_request(Manager *m) {
         ntpmsg.trans_time.sec = htobe32(m->trans_time.tv_sec + OFFSET_1900_1970);
         ntpmsg.trans_time.frac = htobe32(m->trans_time.tv_nsec);
 
-        sockaddr_pretty(&m->current_server_address->sockaddr.sa, m->current_server_address->socklen, true, &pretty);
+        server_address_pretty(m->current_server_address, &pretty);
 
         len = sendto(m->server_socket, &ntpmsg, sizeof(ntpmsg), MSG_DONTWAIT, &m->current_server_address->sockaddr.sa, m->current_server_address->socklen);
         if (len == sizeof(ntpmsg)) {
@@ -376,15 +428,17 @@ static int manager_adjust_clock(Manager *m, double offset, int leap_sec) {
         if (r < 0)
                 return r;
 
+        touch("/var/lib/systemd/clock");
+
         m->drift_ppm = tmx.freq / 65536;
 
         log_debug("  status       : %04i %s\n"
-                  "  time now     : %li.%03lli\n"
+                  "  time now     : %li.%03llu\n"
                   "  constant     : %li\n"
                   "  offset       : %+.3f sec\n"
                   "  freq offset  : %+li (%i ppm)\n",
                   tmx.status, tmx.status & STA_UNSYNC ? "" : "sync",
-                  tmx.time.tv_sec, tmx.time.tv_usec / NSEC_PER_MSEC,
+                  tmx.time.tv_sec, (unsigned long long) (tmx.time.tv_usec / NSEC_PER_MSEC),
                   tmx.constant,
                   (double)tmx.offset / NSEC_PER_SEC,
                   tmx.freq, m->drift_ppm);
@@ -651,7 +705,7 @@ static int manager_receive_response(sd_event_source *source, int fd, uint32_t re
                   "  delay        : %+.3f sec\n"
                   "  packet count : %"PRIu64"\n"
                   "  jitter       : %.3f%s\n"
-                  "  poll interval: %llu\n",
+                  "  poll interval: " USEC_FMT "\n",
                   NTP_FIELD_LEAP(ntpmsg.field),
                   NTP_FIELD_VERSION(ntpmsg.field),
                   NTP_FIELD_MODE(ntpmsg.field),
@@ -668,12 +722,13 @@ static int manager_receive_response(sd_event_source *source, int fd, uint32_t re
                   m->poll_interval_usec / USEC_PER_SEC);
 
         if (!spike) {
+                m->sync = true;
                 r = manager_adjust_clock(m, offset, leap_sec);
                 if (r < 0)
                         log_error("Failed to call clock_adjtime(): %m");
         }
 
-        log_info("interval/delta/delay/jitter/drift %llus/%+.3fs/%.3fs/%.3fs/%+ippm%s",
+        log_info("interval/delta/delay/jitter/drift " USEC_FMT "s/%+.3fs/%.3fs/%.3fs/%+ippm%s",
                  m->poll_interval_usec / USEC_PER_SEC, offset, delay, m->samples_jitter, m->drift_ppm,
                  spike ? " (ignored)" : "");
 
@@ -727,7 +782,7 @@ static int manager_begin(Manager *m) {
 
         m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
 
-        sockaddr_pretty(&m->current_server_address->sockaddr.sa, m->current_server_address->socklen, true, &pretty);
+        server_address_pretty(m->current_server_address, &pretty);
         log_info("Using NTP server %s (%s).", strna(pretty), m->current_server_name->string);
         sd_notifyf(false, "STATUS=Using Time Server %s (%s).", strna(pretty), m->current_server_name->string);
 
@@ -779,7 +834,7 @@ static int manager_resolve_handler(sd_resolve_query *q, int ret, const struct ad
         m->resolve_query = sd_resolve_query_unref(m->resolve_query);
 
         if (ret != 0) {
-                log_info("Failed to resolve %s: %s", m->current_server_name->string, gai_strerror(ret));
+                log_debug("Failed to resolve %s: %s", m->current_server_name->string, gai_strerror(ret));
 
                 /* Try next host */
                 return manager_connect(m);
@@ -964,6 +1019,8 @@ static int manager_new(Manager **ret) {
         _cleanup_manager_free_ Manager *m = NULL;
         int r;
 
+        assert(ret);
+
         m = new0(Manager, 1);
         if (!m)
                 return -ENOMEM;
@@ -989,10 +1046,6 @@ static int manager_new(Manager **ret) {
         if (r < 0)
                 return r;
 
-        r = manager_clock_watch_setup(m);
-        if (r < 0)
-                return r;
-
         *ret = m;
         m = NULL;
 
@@ -1070,10 +1123,10 @@ static bool network_is_online(void) {
         int r;
 
         r = sd_network_get_operational_state(&state);
-        if (r >= 0 && (streq("routable", state) || streq("degraded", state)))
+        if (r >= 0 && STR_IN_SET(state, "routable", "degraded"))
                 return true;
-        else
-                return false;
+
+        return false;
 }
 
 static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents,
@@ -1091,10 +1144,10 @@ static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t re
         connected = (m->server_socket != -1);
 
         if (connected && !online) {
-                log_info("No network connectivity. Suspending.");
+                log_info("No network connectivity, watching for changes.");
                 manager_disconnect(m);
         } else if (!connected && online) {
-                log_info("Network connectivity detected. Resuming.");
+                log_info("Network configuration changed, trying to establish connection.");
                 if (m->current_server_address) {
                         r = manager_begin(m);
                         if (r < 0)
@@ -1141,82 +1194,11 @@ static int manager_network_monitor_listen(Manager *m) {
         return 0;
 }
 
-static int drop_privileges(void) {
-        static const cap_value_t bits[] = {
-                CAP_SYS_TIME,
-        };
-
-        _cleanup_cap_free_ cap_t d = NULL;
-        const char *name = "systemd-timesync";
-        uid_t uid;
-        gid_t gid;
-        int r;
-
-        /* Unfortunately we cannot leave privilege dropping to PID 1
-         * here, since we want to run as user but want to keep te
-         * CAP_SYS_TIME capability. Since file capabilities have been
-         * introduced this cannot be done across exec() anymore,
-         * unless our binary has the capability configured in the file
-         * system, which we want to avoid. */
-
-        r = get_user_creds(&name, &uid, &gid, NULL, NULL);
-        if (r < 0) {
-                log_error("Cannot resolve user name %s: %s", name, strerror(-r));
-                return r;
-        }
-
-        if (setresgid(gid, gid, gid) < 0) {
-                log_error("Failed change group ID: %m");
-                return -errno;
-        }
-
-        if (setgroups(0, NULL) < 0) {
-                log_error("Failed to drop auxiliary groups list: %m");
-                return -errno;
-        }
-
-        if (prctl(PR_SET_KEEPCAPS, 1) < 0) {
-                log_error("Failed to enable keep capabilities flag: %m");
-                return -errno;
-        }
-
-        r = setresuid(uid, uid, uid);
-        if (r < 0) {
-                log_error("Failed change user ID: %m");
-                return -errno;
-        }
-
-        if (prctl(PR_SET_KEEPCAPS, 0) < 0) {
-                log_error("Failed to disable keep capabilities flag: %m");
-                return -errno;
-        }
-
-        r = capability_bounding_set_drop(~(1ULL << CAP_SYS_TIME), true);
-        if (r < 0) {
-                log_error("Failed to drop capabilities: %s", strerror(-r));
-                return r;
-        }
-
-        d = cap_init();
-        if (!d)
-                return log_oom();
-
-        if (cap_set_flag(d, CAP_EFFECTIVE, ELEMENTSOF(bits), bits, CAP_SET) < 0 ||
-            cap_set_flag(d, CAP_PERMITTED, ELEMENTSOF(bits), bits, CAP_SET) < 0) {
-                log_error("Failed to enable capabilities bits: %m");
-                return -errno;
-        }
-
-        if (cap_set_proc(d) < 0) {
-                log_error("Failed to increase capabilities: %m");
-                return -errno;
-        }
-
-        return 0;
-}
-
 int main(int argc, char *argv[]) {
+        const char *user = "systemd-timesync";
         _cleanup_manager_free_ Manager *m = NULL;
+        uid_t uid;
+        gid_t gid;
         int r;
 
         if (argc > 1) {
@@ -1231,7 +1213,17 @@ int main(int argc, char *argv[]) {
 
         umask(0022);
 
-        r = drop_privileges();
+        r = get_user_creds(&user, &uid, &gid, NULL, NULL);
+        if (r < 0) {
+                log_error("Cannot resolve user name %s: %s", user, strerror(-r));
+                return r;
+        }
+
+        r = load_clock_timestamp(uid, gid);
+        if (r < 0)
+                goto out;
+
+        r = drop_privileges(uid, gid, (1ULL << CAP_SYS_TIME));
         if (r < 0)
                 goto out;
 
@@ -1269,6 +1261,10 @@ int main(int argc, char *argv[]) {
 
         sd_event_get_exit_code(m->event, &r);
 
+        /* if we got an authoritative time, store it in the file system */
+        if (m->sync)
+                touch("/var/lib/systemd/clock");
+
 out:
         sd_notify(false, "STATUS=Shutting down...");