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Systemd/src/timesync/timesyncd.c
Zbigniew Jędrzejewski-Szmek a2a5291b3f Reject invalid quoted strings 
String which ended in an unfinished quote were accepted, potentially
with bad memory accesses.

Reject anything which ends in a unfished quote, or contains
non-whitespace characters right after the closing quote.

_FOREACH_WORD now returns the invalid character in *state. But this return
value is not checked anywhere yet.

Also, make 'word' and 'state' variables const pointers, and rename 'w'
to 'word' in various places. Things are easier to read if the same name
is used consistently.

mbiebl_> am I correct that something like this doesn't work
mbiebl_> ExecStart=/usr/bin/encfs --extpass='/bin/systemd-ask-passwd "Unlock EncFS"'
mbiebl_> systemd seems to strip of the quotes
mbiebl_> systemctl status shows
mbiebl_> ExecStart=/usr/bin/encfs --extpass='/bin/systemd-ask-password Unlock EncFS  $RootDir $MountPoint
mbiebl_> which is pretty weird
2014-07-31 04:00:31 -04:00

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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2014 Kay Sievers, Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <time.h>
#include <math.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <sys/timerfd.h>
#include <sys/timex.h>
#include <sys/socket.h>
#include <resolv.h>
#include <sys/prctl.h>
#include <sys/types.h>
#include <grp.h>
#include "missing.h"
#include "util.h"
#include "sparse-endian.h"
#include "log.h"
#include "socket-util.h"
#include "list.h"
#include "ratelimit.h"
#include "strv.h"
#include "conf-parser.h"
#include "sd-event.h"
#include "sd-resolve.h"
#include "sd-daemon.h"
#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)
#ifndef ADJ_SETOFFSET
#define ADJ_SETOFFSET 0x0100 /* add 'time' to current time */
#endif
/* expected accuracy of time synchronization; used to adjust the poll interval */
#define NTP_ACCURACY_SEC 0.2
/*
* "A client MUST NOT under any conditions use a poll interval less
* than 15 seconds."
*/
#define NTP_POLL_INTERVAL_MIN_SEC 32
#define NTP_POLL_INTERVAL_MAX_SEC 2048
/*
* Maximum delta in seconds which the system clock is gradually adjusted
* (slew) to approach the network time. Deltas larger that this are set by
* letting the system time jump. The kernel's limit for adjtime is 0.5s.
*/
#define NTP_MAX_ADJUST 0.4
/* NTP protocol, packet header */
#define NTP_LEAP_PLUSSEC 1
#define NTP_LEAP_MINUSSEC 2
#define NTP_LEAP_NOTINSYNC 3
#define NTP_MODE_CLIENT 3
#define NTP_MODE_SERVER 4
#define NTP_FIELD_LEAP(f) (((f) >> 6) & 3)
#define NTP_FIELD_VERSION(f) (((f) >> 3) & 7)
#define NTP_FIELD_MODE(f) ((f) & 7)
#define NTP_FIELD(l, v, m) (((l) << 6) | ((v) << 3) | (m))
/*
* "NTP timestamps are represented as a 64-bit unsigned fixed-point number,
* in seconds relative to 0h on 1 January 1900."
*/
#define OFFSET_1900_1970 2208988800UL
#define RETRY_USEC (30*USEC_PER_SEC)
#define RATELIMIT_INTERVAL_USEC (10*USEC_PER_SEC)
#define RATELIMIT_BURST 10
#define TIMEOUT_USEC (10*USEC_PER_SEC)
struct ntp_ts {
be32_t sec;
be32_t frac;
} _packed_;
struct ntp_ts_short {
be16_t sec;
be16_t frac;
} _packed_;
struct ntp_msg {
uint8_t field;
uint8_t stratum;
int8_t poll;
int8_t precision;
struct ntp_ts_short root_delay;
struct ntp_ts_short root_dispersion;
char refid[4];
struct ntp_ts reference_time;
struct ntp_ts origin_time;
struct ntp_ts recv_time;
struct ntp_ts trans_time;
} _packed_;
static void manager_free(Manager *m);
DEFINE_TRIVIAL_CLEANUP_FUNC(Manager*, manager_free);
#define _cleanup_manager_free_ _cleanup_(manager_freep)
static int manager_arm_timer(Manager *m, usec_t next);
static int manager_clock_watch_setup(Manager *m);
static int manager_connect(Manager *m);
static void manager_disconnect(Manager *m);
static double ntp_ts_to_d(const struct ntp_ts *ts) {
return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX);
}
static double ts_to_d(const struct timespec *ts) {
return ts->tv_sec + (1.0e-9 * ts->tv_nsec);
}
static double tv_to_d(const struct timeval *tv) {
return tv->tv_sec + (1.0e-6 * tv->tv_usec);
}
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;
assert(m);
assert(m->current_server_name);
assert(m->current_server_address);
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);
}
static int manager_send_request(Manager *m) {
_cleanup_free_ char *pretty = NULL;
struct ntp_msg ntpmsg = {
/*
* "The client initializes the NTP message header, sends the request
* to the server, and strips the time of day from the Transmit
* Timestamp field of the reply. For this purpose, all the NTP
* header fields are set to 0, except the Mode, VN, and optional
* Transmit Timestamp fields."
*/
.field = NTP_FIELD(0, 4, NTP_MODE_CLIENT),
};
ssize_t len;
int r;
assert(m);
assert(m->current_server_name);
assert(m->current_server_address);
m->event_timeout = sd_event_source_unref(m->event_timeout);
/*
* Set transmit timestamp, remember it; the server will send that back
* as the origin timestamp and we have an indication that this is the
* matching answer to our request.
*
* The actual value does not matter, We do not care about the correct
* NTP UINT_MAX fraction; we just pass the plain nanosecond value.
*/
assert_se(clock_gettime(CLOCK_MONOTONIC, &m->trans_time_mon) >= 0);
assert_se(clock_gettime(CLOCK_REALTIME, &m->trans_time) >= 0);
ntpmsg.trans_time.sec = htobe32(m->trans_time.tv_sec + OFFSET_1900_1970);
ntpmsg.trans_time.frac = htobe32(m->trans_time.tv_nsec);
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)) {
m->pending = true;
log_debug("Sent NTP request to %s (%s).", strna(pretty), m->current_server_name->string);
} else {
log_debug("Sending NTP request to %s (%s) failed: %m", strna(pretty), m->current_server_name->string);
return manager_connect(m);
}
/* re-arm timer with increasing timeout, in case the packets never arrive back */
if (m->retry_interval > 0) {
if (m->retry_interval < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
m->retry_interval *= 2;
} else
m->retry_interval = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
r = manager_arm_timer(m, m->retry_interval);
if (r < 0) {
log_error("Failed to rearm timer: %s", strerror(-r));
return r;
}
r = sd_event_add_time(
m->event,
&m->event_timeout,
CLOCK_MONOTONIC,
now(CLOCK_MONOTONIC) + TIMEOUT_USEC, 0,
manager_timeout, m);
if (r < 0) {
log_error("Failed to arm timeout timer: %s", strerror(-r));
return r;
}
return 0;
}
static int manager_timer(sd_event_source *source, usec_t usec, void *userdata) {
Manager *m = userdata;
assert(m);
return manager_send_request(m);
}
static int manager_arm_timer(Manager *m, usec_t next) {
int r;
assert(m);
assert(m->event_receive);
if (next == 0) {
m->event_timer = sd_event_source_unref(m->event_timer);
return 0;
}
if (m->event_timer) {
r = sd_event_source_set_time(m->event_timer, now(CLOCK_MONOTONIC) + next);
if (r < 0)
return r;
return sd_event_source_set_enabled(m->event_timer, SD_EVENT_ONESHOT);
}
return sd_event_add_time(
m->event,
&m->event_timer,
CLOCK_MONOTONIC,
now(CLOCK_MONOTONIC) + next, 0,
manager_timer, m);
}
static int manager_clock_watch(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
Manager *m = userdata;
assert(m);
/* rearm timer */
manager_clock_watch_setup(m);
/* skip our own jumps */
if (m->jumped) {
m->jumped = false;
return 0;
}
/* resync */
log_info("System time changed. Resyncing.");
m->poll_resync = true;
return manager_send_request(m);
}
/* wake up when the system time changes underneath us */
static int manager_clock_watch_setup(Manager *m) {
struct itimerspec its = {
.it_value.tv_sec = TIME_T_MAX
};
int r;
assert(m);
m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
safe_close(m->clock_watch_fd);
m->clock_watch_fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK|TFD_CLOEXEC);
if (m->clock_watch_fd < 0) {
log_error("Failed to create timerfd: %m");
return -errno;
}
if (timerfd_settime(m->clock_watch_fd, TFD_TIMER_ABSTIME|TFD_TIMER_CANCEL_ON_SET, &its, NULL) < 0) {
log_error("Failed to set up timerfd: %m");
return -errno;
}
r = sd_event_add_io(m->event, &m->event_clock_watch, m->clock_watch_fd, EPOLLIN, manager_clock_watch, m);
if (r < 0) {
log_error("Failed to create clock watch event source: %s", strerror(-r));
return r;
}
return 0;
}
static int manager_adjust_clock(Manager *m, double offset, int leap_sec) {
struct timex tmx = {};
int r;
assert(m);
/*
* For small deltas, tell the kernel to gradually adjust the system
* clock to the NTP time, larger deltas are just directly set.
*/
if (fabs(offset) < NTP_MAX_ADJUST) {
tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_OFFSET | ADJ_TIMECONST | ADJ_MAXERROR | ADJ_ESTERROR;
tmx.status = STA_PLL;
tmx.offset = offset * NSEC_PER_SEC;
tmx.constant = log2i(m->poll_interval_usec / USEC_PER_SEC) - 4;
tmx.maxerror = 0;
tmx.esterror = 0;
log_debug(" adjust (slew): %+.3f sec\n", offset);
} else {
tmx.modes = ADJ_STATUS | ADJ_NANO | ADJ_SETOFFSET;
/* ADJ_NANO uses nanoseconds in the microseconds field */
tmx.time.tv_sec = (long)offset;
tmx.time.tv_usec = (offset - tmx.time.tv_sec) * NSEC_PER_SEC;
/* the kernel expects -0.3s as {-1, 7000.000.000} */
if (tmx.time.tv_usec < 0) {
tmx.time.tv_sec -= 1;
tmx.time.tv_usec += NSEC_PER_SEC;
}
m->jumped = true;
log_debug(" adjust (jump): %+.3f sec\n", offset);
}
/*
* An unset STA_UNSYNC will enable the kernel's 11-minute mode,
* which syncs the system time periodically to the RTC.
*
* In case the RTC runs in local time, never touch the RTC,
* we have no way to properly handle daylight saving changes and
* mobile devices moving between time zones.
*/
if (m->rtc_local_time)
tmx.status |= STA_UNSYNC;
switch (leap_sec) {
case 1:
tmx.status |= STA_INS;
break;
case -1:
tmx.status |= STA_DEL;
break;
}
r = clock_adjtime(CLOCK_REALTIME, &tmx);
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.%03llu\n"
" constant : %li\n"
" offset : %+.3f sec\n"
" freq offset : %+li (%i ppm)\n",
tmx.status, tmx.status & STA_UNSYNC ? "unsync" : "sync",
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);
return 0;
}
static bool manager_sample_spike_detection(Manager *m, double offset, double delay) {
unsigned int i, idx_cur, idx_new, idx_min;
double jitter;
double j;
assert(m);
m->packet_count++;
/* ignore initial sample */
if (m->packet_count == 1)
return false;
/* store the current data in our samples array */
idx_cur = m->samples_idx;
idx_new = (idx_cur + 1) % ELEMENTSOF(m->samples);
m->samples_idx = idx_new;
m->samples[idx_new].offset = offset;
m->samples[idx_new].delay = delay;
/* calculate new jitter value from the RMS differences relative to the lowest delay sample */
jitter = m->samples_jitter;
for (idx_min = idx_cur, i = 0; i < ELEMENTSOF(m->samples); i++)
if (m->samples[i].delay > 0 && m->samples[i].delay < m->samples[idx_min].delay)
idx_min = i;
j = 0;
for (i = 0; i < ELEMENTSOF(m->samples); i++)
j += square(m->samples[i].offset - m->samples[idx_min].offset);
m->samples_jitter = sqrt(j / (ELEMENTSOF(m->samples) - 1));
/* ignore samples when resyncing */
if (m->poll_resync)
return false;
/* always accept offset if we are farther off than the round-trip delay */
if (fabs(offset) > delay)
return false;
/* we need a few samples before looking at them */
if (m->packet_count < 4)
return false;
/* do not accept anything worse than the maximum possible error of the best sample */
if (fabs(offset) > m->samples[idx_min].delay)
return true;
/* compare the difference between the current offset to the previous offset and jitter */
return fabs(offset - m->samples[idx_cur].offset) > 3 * jitter;
}
static void manager_adjust_poll(Manager *m, double offset, bool spike) {
assert(m);
if (m->poll_resync) {
m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
m->poll_resync = false;
return;
}
/* set to minimal poll interval */
if (!spike && fabs(offset) > NTP_ACCURACY_SEC) {
m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
return;
}
/* increase polling interval */
if (fabs(offset) < NTP_ACCURACY_SEC * 0.25) {
if (m->poll_interval_usec < NTP_POLL_INTERVAL_MAX_SEC * USEC_PER_SEC)
m->poll_interval_usec *= 2;
return;
}
/* decrease polling interval */
if (spike || fabs(offset) > NTP_ACCURACY_SEC * 0.75) {
if (m->poll_interval_usec > NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC)
m->poll_interval_usec /= 2;
return;
}
}
static bool sockaddr_equal(union sockaddr_union *a, union sockaddr_union *b) {
assert(a);
assert(b);
if (a->sa.sa_family != b->sa.sa_family)
return false;
if (a->sa.sa_family == AF_INET)
return a->in.sin_addr.s_addr == b->in.sin_addr.s_addr;
if (a->sa.sa_family == AF_INET6)
return memcmp(&a->in6.sin6_addr, &b->in6.sin6_addr, sizeof(a->in6.sin6_addr)) == 0;
return false;
}
static int manager_receive_response(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
Manager *m = userdata;
struct ntp_msg ntpmsg;
struct iovec iov = {
.iov_base = &ntpmsg,
.iov_len = sizeof(ntpmsg),
};
union {
struct cmsghdr cmsghdr;
uint8_t buf[CMSG_SPACE(sizeof(struct timeval))];
} control;
union sockaddr_union server_addr;
struct msghdr msghdr = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = &control,
.msg_controllen = sizeof(control),
.msg_name = &server_addr,
.msg_namelen = sizeof(server_addr),
};
struct cmsghdr *cmsg;
struct timespec now_ts;
struct timeval *recv_time;
ssize_t len;
double origin, receive, trans, dest;
double delay, offset;
bool spike;
int leap_sec;
int r;
assert(source);
assert(m);
if (revents & (EPOLLHUP|EPOLLERR)) {
log_warning("Server connection returned error.");
return manager_connect(m);
}
len = recvmsg(fd, &msghdr, MSG_DONTWAIT);
if (len < 0) {
if (errno == EAGAIN)
return 0;
log_warning("Error receiving message. Disconnecting.");
return manager_connect(m);
}
if (iov.iov_len < sizeof(struct ntp_msg)) {
log_warning("Invalid response from server. Disconnecting.");
return manager_connect(m);
}
if (!m->current_server_name ||
!m->current_server_address ||
!sockaddr_equal(&server_addr, &m->current_server_address->sockaddr)) {
log_debug("Response from unknown server.");
return 0;
}
recv_time = NULL;
for (cmsg = CMSG_FIRSTHDR(&msghdr); cmsg; cmsg = CMSG_NXTHDR(&msghdr, cmsg)) {
if (cmsg->cmsg_level != SOL_SOCKET)
continue;
switch (cmsg->cmsg_type) {
case SCM_TIMESTAMP:
recv_time = (struct timeval *) CMSG_DATA(cmsg);
break;
}
}
if (!recv_time) {
log_error("Invalid packet timestamp.");
return -EINVAL;
}
if (!m->pending) {
log_debug("Unexpected reply. Ignoring.");
return 0;
}
/* check our "time cookie" (we just stored nanoseconds in the fraction field) */
if (be32toh(ntpmsg.origin_time.sec) != m->trans_time.tv_sec + OFFSET_1900_1970 ||
be32toh(ntpmsg.origin_time.frac) != m->trans_time.tv_nsec) {
log_debug("Invalid reply; not our transmit time. Ignoring.");
return 0;
}
m->event_timeout = sd_event_source_unref(m->event_timeout);
if (be32toh(ntpmsg.recv_time.sec) < TIME_EPOCH + OFFSET_1900_1970 ||
be32toh(ntpmsg.trans_time.sec) < TIME_EPOCH + OFFSET_1900_1970) {
log_debug("Invalid reply, returned times before epoch. Ignoring.");
return manager_connect(m);
}
if (NTP_FIELD_LEAP(ntpmsg.field) == NTP_LEAP_NOTINSYNC) {
log_debug("Server is not synchronized. Disconnecting.");
return manager_connect(m);
}
if (!IN_SET(NTP_FIELD_VERSION(ntpmsg.field), 3, 4)) {
log_debug("Response NTPv%d. Disconnecting.", NTP_FIELD_VERSION(ntpmsg.field));
return manager_connect(m);
}
if (NTP_FIELD_MODE(ntpmsg.field) != NTP_MODE_SERVER) {
log_debug("Unsupported mode %d. Disconnecting.", NTP_FIELD_MODE(ntpmsg.field));
return manager_connect(m);
}
/* valid packet */
m->pending = false;
m->retry_interval = 0;
/* announce leap seconds */
if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_PLUSSEC)
leap_sec = 1;
else if (NTP_FIELD_LEAP(ntpmsg.field) & NTP_LEAP_MINUSSEC)
leap_sec = -1;
else
leap_sec = 0;
/*
* "Timestamp Name ID When Generated
* ------------------------------------------------------------
* Originate Timestamp T1 time request sent by client
* Receive Timestamp T2 time request received by server
* Transmit Timestamp T3 time reply sent by server
* Destination Timestamp T4 time reply received by client
*
* The round-trip delay, d, and system clock offset, t, are defined as:
* d = (T4 - T1) - (T3 - T2) t = ((T2 - T1) + (T3 - T4)) / 2"
*/
assert_se(clock_gettime(CLOCK_MONOTONIC, &now_ts) >= 0);
origin = tv_to_d(recv_time) - (ts_to_d(&now_ts) - ts_to_d(&m->trans_time_mon)) + OFFSET_1900_1970;
receive = ntp_ts_to_d(&ntpmsg.recv_time);
trans = ntp_ts_to_d(&ntpmsg.trans_time);
dest = tv_to_d(recv_time) + OFFSET_1900_1970;
offset = ((receive - origin) + (trans - dest)) / 2;
delay = (dest - origin) - (trans - receive);
spike = manager_sample_spike_detection(m, offset, delay);
manager_adjust_poll(m, offset, spike);
log_debug("NTP response:\n"
" leap : %u\n"
" version : %u\n"
" mode : %u\n"
" stratum : %u\n"
" precision : %.6f sec (%d)\n"
" reference : %.4s\n"
" origin : %.3f\n"
" receive : %.3f\n"
" transmit : %.3f\n"
" dest : %.3f\n"
" offset : %+.3f sec\n"
" delay : %+.3f sec\n"
" packet count : %"PRIu64"\n"
" jitter : %.3f%s\n"
" poll interval: " USEC_FMT "\n",
NTP_FIELD_LEAP(ntpmsg.field),
NTP_FIELD_VERSION(ntpmsg.field),
NTP_FIELD_MODE(ntpmsg.field),
ntpmsg.stratum,
exp2(ntpmsg.precision), ntpmsg.precision,
ntpmsg.stratum == 1 ? ntpmsg.refid : "n/a",
origin - OFFSET_1900_1970,
receive - OFFSET_1900_1970,
trans - OFFSET_1900_1970,
dest - OFFSET_1900_1970,
offset, delay,
m->packet_count,
m->samples_jitter, spike ? " spike" : "",
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 " 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)" : "");
r = manager_arm_timer(m, m->poll_interval_usec);
if (r < 0) {
log_error("Failed to rearm timer: %s", strerror(-r));
return r;
}
return 0;
}
static int manager_listen_setup(Manager *m) {
union sockaddr_union addr = {};
static const int tos = IPTOS_LOWDELAY;
static const int on = 1;
int r;
assert(m);
assert(m->server_socket < 0);
assert(!m->event_receive);
assert(m->current_server_address);
addr.sa.sa_family = m->current_server_address->sockaddr.sa.sa_family;
m->server_socket = socket(addr.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
if (m->server_socket < 0)
return -errno;
r = bind(m->server_socket, &addr.sa, m->current_server_address->socklen);
if (r < 0)
return -errno;
r = setsockopt(m->server_socket, SOL_SOCKET, SO_TIMESTAMP, &on, sizeof(on));
if (r < 0)
return -errno;
setsockopt(m->server_socket, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
return sd_event_add_io(m->event, &m->event_receive, m->server_socket, EPOLLIN, manager_receive_response, m);
}
static int manager_begin(Manager *m) {
_cleanup_free_ char *pretty = NULL;
int r;
assert(m);
assert_return(m->current_server_name, -EHOSTUNREACH);
assert_return(m->current_server_address, -EHOSTUNREACH);
m->poll_interval_usec = NTP_POLL_INTERVAL_MIN_SEC * USEC_PER_SEC;
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);
r = manager_listen_setup(m);
if (r < 0) {
log_warning("Failed to setup connection socket: %s", strerror(-r));
return r;
}
r = manager_clock_watch_setup(m);
if (r < 0)
return r;
return manager_send_request(m);
}
static void server_name_flush_addresses(ServerName *n) {
ServerAddress *a;
assert(n);
while ((a = n->addresses)) {
LIST_REMOVE(addresses, n->addresses, a);
free(a);
}
}
static void manager_flush_names(Manager *m) {
ServerName *n;
assert(m);
while ((n = m->servers)) {
LIST_REMOVE(names, m->servers, n);
free(n->string);
server_name_flush_addresses(n);
free(n);
}
}
static int manager_resolve_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, void *userdata) {
Manager *m = userdata;
ServerAddress *a, *last = NULL;
assert(q);
assert(m);
assert(m->current_server_name);
m->resolve_query = sd_resolve_query_unref(m->resolve_query);
if (ret != 0) {
log_debug("Failed to resolve %s: %s", m->current_server_name->string, gai_strerror(ret));
/* Try next host */
return manager_connect(m);
}
server_name_flush_addresses(m->current_server_name);
for (; ai; ai = ai->ai_next) {
_cleanup_free_ char *pretty = NULL;
assert(ai->ai_addr);
assert(ai->ai_addrlen >= offsetof(struct sockaddr, sa_data));
assert(ai->ai_addrlen <= sizeof(union sockaddr_union));
if (!IN_SET(ai->ai_addr->sa_family, AF_INET, AF_INET6)) {
log_warning("Unsuitable address protocol for %s", m->current_server_name->string);
continue;
}
a = new0(ServerAddress, 1);
if (!a)
return log_oom();
memcpy(&a->sockaddr, ai->ai_addr, ai->ai_addrlen);
a->socklen = ai->ai_addrlen;
LIST_INSERT_AFTER(addresses, m->current_server_name->addresses, last, a);
last = a;
sockaddr_pretty(&a->sockaddr.sa, a->socklen, true, &pretty);
log_debug("Resolved address %s for %s.", pretty, m->current_server_name->string);
}
if (!m->current_server_name->addresses) {
log_error("Failed to find suitable address for host %s.", m->current_server_name->string);
/* Try next host */
return manager_connect(m);
}
m->current_server_address = m->current_server_name->addresses;
return manager_begin(m);
}
static int manager_retry(sd_event_source *source, usec_t usec, void *userdata) {
Manager *m = userdata;
assert(m);
return manager_connect(m);
}
static int manager_connect(Manager *m) {
struct addrinfo hints = {
.ai_flags = AI_NUMERICSERV|AI_ADDRCONFIG,
.ai_socktype = SOCK_DGRAM,
};
int r;
assert(m);
manager_disconnect(m);
m->event_retry = sd_event_source_unref(m->event_retry);
if (!ratelimit_test(&m->ratelimit)) {
log_debug("Slowing down attempts to contact servers.");
r = sd_event_add_time(m->event, &m->event_retry, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + RETRY_USEC, 0, manager_retry, m);
if (r < 0) {
log_error("Failed to create retry timer: %s", strerror(-r));
return r;
}
return 0;
}
/* If we already are operating on some address, switch to the
* next one. */
if (m->current_server_address && m->current_server_address->addresses_next)
m->current_server_address = m->current_server_address->addresses_next;
else {
/* Hmm, we are through all addresses, let's look for the next host instead */
m->current_server_address = NULL;
if (m->current_server_name && m->current_server_name->names_next)
m->current_server_name = m->current_server_name->names_next;
else {
if (!m->servers) {
m->current_server_name = NULL;
log_debug("No server found.");
return 0;
}
m->current_server_name = m->servers;
}
/* Tell the resolver to reread /etc/resolv.conf, in
* case it changed. */
res_init();
r = sd_resolve_getaddrinfo(m->resolve, &m->resolve_query, m->current_server_name->string, "123", &hints, manager_resolve_handler, m);
if (r < 0) {
log_error("Failed to create resolver: %s", strerror(-r));
return r;
}
return 1;
}
r = manager_begin(m);
if (r < 0)
return r;
return 1;
}
static int manager_add_server(Manager *m, const char *server) {
ServerName *n, *tail;
assert(m);
assert(server);
n = new0(ServerName, 1);
if (!n)
return -ENOMEM;
n->string = strdup(server);
if (!n->string) {
free(n);
return -ENOMEM;
}
LIST_FIND_TAIL(names, m->servers, tail);
LIST_INSERT_AFTER(names, m->servers, tail, n);
return 0;
}
static int manager_add_server_string(Manager *m, const char *string) {
const char *word, *state;
size_t l;
int r;
assert(m);
assert(string);
FOREACH_WORD_QUOTED(word, l, string, state) {
char t[l+1];
memcpy(t, word, l);
t[l] = 0;
r = manager_add_server(m, t);
if (r < 0)
log_error("Failed to add server %s to configuration, ignoring: %s", t, strerror(-r));
}
return 0;
}
static void manager_disconnect(Manager *m) {
assert(m);
m->resolve_query = sd_resolve_query_unref(m->resolve_query);
m->event_timer = sd_event_source_unref(m->event_timer);
m->event_receive = sd_event_source_unref(m->event_receive);
m->server_socket = safe_close(m->server_socket);
m->event_clock_watch = sd_event_source_unref(m->event_clock_watch);
m->clock_watch_fd = safe_close(m->clock_watch_fd);
m->event_timeout = sd_event_source_unref(m->event_timeout);
sd_notifyf(false, "STATUS=Idle.");
}
static int manager_new(Manager **ret) {
_cleanup_manager_free_ Manager *m = NULL;
int r;
assert(ret);
m = new0(Manager, 1);
if (!m)
return -ENOMEM;
m->server_socket = m->clock_watch_fd = -1;
RATELIMIT_INIT(m->ratelimit, RATELIMIT_INTERVAL_USEC, RATELIMIT_BURST);
r = sd_event_default(&m->event);
if (r < 0)
return r;
sd_event_set_watchdog(m->event, true);
sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
r = sd_resolve_default(&m->resolve);
if (r < 0)
return r;
r = sd_resolve_attach_event(m->resolve, m->event, 0);
if (r < 0)
return r;
*ret = m;
m = NULL;
return 0;
}
static void manager_free(Manager *m) {
if (!m)
return;
manager_disconnect(m);
manager_flush_names(m);
sd_event_source_unref(m->event_retry);
sd_event_source_unref(m->network_event_source);
sd_network_monitor_unref(m->network_monitor);
sd_resolve_unref(m->resolve);
sd_event_unref(m->event);
free(m);
}
int config_parse_servers(
const char *unit,
const char *filename,
unsigned line,
const char *section,
unsigned section_line,
const char *lvalue,
int ltype,
const char *rvalue,
void *data,
void *userdata) {
Manager *m = userdata;
assert(filename);
assert(lvalue);
assert(rvalue);
manager_flush_names(m);
manager_add_server_string(m, rvalue);
return 0;
}
static int manager_parse_config_file(Manager *m) {
return config_parse(NULL, "/etc/systemd/timesyncd.conf", NULL,
"Time\0",
config_item_perf_lookup, timesyncd_gperf_lookup,
false, false, true, m);
}
static bool network_is_online(void) {
_cleanup_free_ char *state = NULL;
int r;
r = sd_network_get_operational_state(&state);
if (r >= 0 && STR_IN_SET(state, "routable", "degraded"))
return true;
return false;
}
static int manager_network_event_handler(sd_event_source *s, int fd, uint32_t revents,
void *userdata) {
Manager *m = userdata;
bool connected, online;
int r;
assert(m);
/* check if the machine is online */
online = network_is_online();
/* check if the client is currently connected */
connected = (m->server_socket != -1);
if (connected && !online) {
log_info("No network connectivity, watching for changes.");
manager_disconnect(m);
} else if (!connected && online) {
log_info("Network configuration changed, trying to establish connection.");
if (m->current_server_address) {
r = manager_begin(m);
if (r < 0)
return r;
} else {
r = manager_connect(m);
if (r < 0)
return r;
}
}
sd_network_monitor_flush(m->network_monitor);
return 0;
}
static int manager_network_monitor_listen(Manager *m) {
_cleanup_event_source_unref_ sd_event_source *event_source = NULL;
_cleanup_network_monitor_unref_ sd_network_monitor *monitor = NULL;
int r, fd, events;
r = sd_network_monitor_new(&monitor, NULL);
if (r < 0)
return r;
fd = sd_network_monitor_get_fd(monitor);
if (fd < 0)
return fd;
events = sd_network_monitor_get_events(monitor);
if (events < 0)
return events;
r = sd_event_add_io(m->event, &event_source, fd, events,
&manager_network_event_handler, m);
if (r < 0)
return r;
m->network_monitor = monitor;
m->network_event_source = event_source;
monitor = NULL;
event_source = NULL;
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) {
log_error("This program does not take arguments.");
return EXIT_FAILURE;
}
log_set_target(LOG_TARGET_AUTO);
log_set_facility(LOG_CRON);
log_parse_environment();
log_open();
umask(0022);
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;
assert_se(sigprocmask_many(SIG_BLOCK, SIGTERM, SIGINT, -1) == 0);
r = manager_new(&m);
if (r < 0) {
log_error("Failed to allocate manager: %s", strerror(-r));
goto out;
}
if (clock_is_localtime() > 0) {
log_info("The system is configured to read the RTC time in the local time zone. "
"This mode can not be fully supported. All system time to RTC updates are disabled.");
m->rtc_local_time = true;
}
manager_add_server_string(m, NTP_SERVERS);
manager_parse_config_file(m);
r = manager_network_monitor_listen(m);
if (r < 0) {
log_error("Failed to listen to networkd events: %s", strerror(-r));
goto out;
}
log_debug("systemd-timesyncd running as pid %lu", (unsigned long) getpid());
sd_notify(false, "READY=1");
if (network_is_online()) {
r = manager_connect(m);
if (r < 0)
goto out;
}
r = sd_event_loop(m->event);
if (r < 0) {
log_error("Failed to run event loop: %s", strerror(-r));
goto out;
}
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...");
return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}
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