File: main.c

package info (click to toggle)
chrony 3.0-4+deb9u2
  • links: PTS, VCS
  • area: main
  • in suites: stretch
  • size: 2,496 kB
  • sloc: ansic: 23,531; sh: 2,022; yacc: 866; makefile: 195
file content (587 lines) | stat: -rw-r--r-- 14,686 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
/*
  chronyd/chronyc - Programs for keeping computer clocks accurate.

 **********************************************************************
 * Copyright (C) Richard P. Curnow  1997-2003
 * Copyright (C) John G. Hasler  2009
 * Copyright (C) Miroslav Lichvar  2012-2015
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 * 
 * This program 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
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 * 
 **********************************************************************

  =======================================================================

  The main program
  */

#include "config.h"

#include "sysincl.h"

#include "main.h"
#include "sched.h"
#include "local.h"
#include "sys.h"
#include "ntp_io.h"
#include "ntp_signd.h"
#include "ntp_sources.h"
#include "ntp_core.h"
#include "sources.h"
#include "sourcestats.h"
#include "reference.h"
#include "logging.h"
#include "conf.h"
#include "cmdmon.h"
#include "keys.h"
#include "manual.h"
#include "rtc.h"
#include "refclock.h"
#include "clientlog.h"
#include "nameserv.h"
#include "privops.h"
#include "smooth.h"
#include "tempcomp.h"
#include "util.h"

/* ================================================== */

/* Set when the initialisation chain has been completed.  Prevents finalisation
 * chain being run if a fatal error happened early. */

static int initialised = 0;

static int exit_status = 0;

static int reload = 0;

static REF_Mode ref_mode = REF_ModeNormal;

/* ================================================== */

static void
do_platform_checks(void)
{
  /* Require at least 32-bit integers, two's complement representation and
     the usual implementation of conversion of unsigned integers */
  assert(sizeof (int) >= 4);
  assert(-1 == ~0);
  assert((int32_t)4294967295U == (int32_t)-1);
}

/* ================================================== */

static void
delete_pidfile(void)
{
  const char *pidfile = CNF_GetPidFile();
  /* Don't care if this fails, there's not a lot we can do */
  unlink(pidfile);
}

/* ================================================== */

void
MAI_CleanupAndExit(void)
{
  if (!initialised) exit(exit_status);
  
  if (CNF_GetDumpOnExit()) {
    SRC_DumpSources();
  }

  /* Don't update clock when removing sources */
  REF_SetMode(REF_ModeIgnore);

  SMT_Finalise();
  TMC_Finalise();
  MNL_Finalise();
  CLG_Finalise();
  NSD_Finalise();
  NSR_Finalise();
  SST_Finalise();
  NCR_Finalise();
  NIO_Finalise();
  CAM_Finalise();
  KEY_Finalise();
  RCL_Finalise();
  SRC_Finalise();
  REF_Finalise();
  RTC_Finalise();
  SYS_Finalise();
  SCH_Finalise();
  LCL_Finalise();
  PRV_Finalise();

  delete_pidfile();
  
  CNF_Finalise();
  LOG_Finalise();

  HSH_Finalise();

  exit(exit_status);
}

/* ================================================== */

static void
signal_cleanup(int x)
{
  if (!initialised) exit(0);
  SCH_QuitProgram();
}

/* ================================================== */

static void
quit_timeout(void *arg)
{
  /* Return with non-zero status if the clock is not synchronised */
  exit_status = REF_GetOurStratum() >= NTP_MAX_STRATUM;
  SCH_QuitProgram();
}

/* ================================================== */

static void
ntp_source_resolving_end(void)
{
  NSR_SetSourceResolvingEndHandler(NULL);

  if (reload) {
    /* Note, we want reload to come well after the initialisation from
       the real time clock - this gives us a fighting chance that the
       system-clock scale for the reloaded samples still has a
       semblence of validity about it. */
    SRC_ReloadSources();
  }

  SRC_RemoveDumpFiles();
  RTC_StartMeasurements();
  RCL_StartRefclocks();
  NSR_StartSources();
  NSR_AutoStartSources();

  /* Special modes can end only when sources update their reachability.
     Give up immediatelly if there are no active sources. */
  if (ref_mode != REF_ModeNormal && !SRC_ActiveSources()) {
    REF_SetUnsynchronised();
  }
}

/* ================================================== */

static void
post_init_ntp_hook(void *anything)
{
  if (ref_mode == REF_ModeInitStepSlew) {
    /* Remove the initstepslew sources and set normal mode */
    NSR_RemoveAllSources();
    ref_mode = REF_ModeNormal;
    REF_SetMode(ref_mode);
  }

  /* Close the pipe to the foreground process so it can exit */
  LOG_CloseParentFd();

  CNF_AddSources();
  CNF_AddBroadcasts();

  NSR_SetSourceResolvingEndHandler(ntp_source_resolving_end);
  NSR_ResolveSources();
}

/* ================================================== */

static void
reference_mode_end(int result)
{
  switch (ref_mode) {
    case REF_ModeNormal:
    case REF_ModeUpdateOnce:
    case REF_ModePrintOnce:
      exit_status = !result;
      SCH_QuitProgram();
      break;
    case REF_ModeInitStepSlew:
      /* Switch to the normal mode, the delay is used to prevent polling
         interval shorter than the burst interval if some configured servers
         were used also for initstepslew */
      SCH_AddTimeoutByDelay(2.0, post_init_ntp_hook, NULL);
      break;
    default:
      assert(0);
  }
}

/* ================================================== */

static void
post_init_rtc_hook(void *anything)
{
  if (CNF_GetInitSources() > 0) {
    CNF_AddInitSources();
    NSR_StartSources();
    assert(REF_GetMode() != REF_ModeNormal);
    /* Wait for mode end notification */
  } else {
    (post_init_ntp_hook)(NULL);
  }
}

/* ================================================== */
/* Return 1 if the process exists on the system. */

static int
does_process_exist(int pid)
{
  int status;
  status = getsid(pid);
  if (status >= 0) {
    return 1;
  } else {
    return 0;
  }
}

/* ================================================== */

static int
maybe_another_chronyd_running(int *other_pid)
{
  const char *pidfile = CNF_GetPidFile();
  FILE *in;
  int pid, count;
  
  *other_pid = 0;

  in = fopen(pidfile, "r");
  if (!in) return 0;

  count = fscanf(in, "%d", &pid);
  fclose(in);
  
  if (count != 1) return 0;

  *other_pid = pid;
  return does_process_exist(pid);
  
}

/* ================================================== */

static void
write_lockfile(void)
{
  const char *pidfile = CNF_GetPidFile();
  FILE *out;

  out = fopen(pidfile, "w");
  if (!out) {
    LOG_FATAL(LOGF_Main, "could not open lockfile %s for writing", pidfile);
  } else {
    fprintf(out, "%d\n", (int)getpid());
    fclose(out);
  }
}

/* ================================================== */

static void
go_daemon(void)
{
  int pid, fd, pipefd[2];

  /* Create pipe which will the daemon use to notify the grandparent
     when it's initialised or send an error message */
  if (pipe(pipefd)) {
    LOG_FATAL(LOGF_Main, "Could not detach, pipe failed : %s", strerror(errno));
  }

  /* Does this preserve existing signal handlers? */
  pid = fork();

  if (pid < 0) {
    LOG_FATAL(LOGF_Main, "Could not detach, fork failed : %s", strerror(errno));
  } else if (pid > 0) {
    /* In the 'grandparent' */
    char message[1024];
    int r;

    close(pipefd[1]);
    r = read(pipefd[0], message, sizeof (message));
    if (r) {
      if (r > 0) {
        /* Print the error message from the child */
        message[sizeof (message) - 1] = '\0';
        fprintf(stderr, "%s\n", message);
      }
      exit(1);
    } else
      exit(0);
  } else {
    close(pipefd[0]);

    setsid();

    /* Do 2nd fork, as-per recommended practice for launching daemons. */
    pid = fork();

    if (pid < 0) {
      LOG_FATAL(LOGF_Main, "Could not detach, fork failed : %s", strerror(errno));
    } else if (pid > 0) {
      exit(0); /* In the 'parent' */
    } else {
      /* In the child we want to leave running as the daemon */

      /* Change current directory to / */
      if (chdir("/") < 0) {
        LOG_FATAL(LOGF_Main, "Could not chdir to / : %s", strerror(errno));
      }

      /* Don't keep stdin/out/err from before. But don't close
         the parent pipe yet. */
      for (fd=0; fd<1024; fd++) {
        if (fd != pipefd[1])
          close(fd);
      }

      LOG_SetParentFd(pipefd[1]);
    }
  }
}

/* ================================================== */

int main
(int argc, char **argv)
{
  const char *conf_file = DEFAULT_CONF_FILE;
  const char *progname = argv[0];
  char *user = NULL;
  struct passwd *pw;
  int debug = 0, nofork = 0, address_family = IPADDR_UNSPEC;
  int do_init_rtc = 0, restarted = 0, timeout = 0;
  int other_pid;
  int scfilter_level = 0, lock_memory = 0, sched_priority = 0;
  int system_log = 1;
  int config_args = 0;

  do_platform_checks();

  LOG_Initialise();

  /* Parse command line options */
  while (++argv, (--argc)>0) {

    if (!strcmp("-f", *argv)) {
      ++argv, --argc;
      conf_file = *argv;
    } else if (!strcmp("-P", *argv)) {
      ++argv, --argc;
      if (argc == 0 || sscanf(*argv, "%d", &sched_priority) != 1) {
        LOG_FATAL(LOGF_Main, "Bad scheduler priority");
      }
    } else if (!strcmp("-m", *argv)) {
      lock_memory = 1;
    } else if (!strcmp("-r", *argv)) {
      reload = 1;
    } else if (!strcmp("-R", *argv)) {
      restarted = 1;
    } else if (!strcmp("-u", *argv)) {
      ++argv, --argc;
      if (argc == 0) {
        LOG_FATAL(LOGF_Main, "Missing user name");
      } else {
        user = *argv;
      }
    } else if (!strcmp("-F", *argv)) {
      ++argv, --argc;
      if (argc == 0 || sscanf(*argv, "%d", &scfilter_level) != 1)
        LOG_FATAL(LOGF_Main, "Bad syscall filter level");
    } else if (!strcmp("-s", *argv)) {
      do_init_rtc = 1;
    } else if (!strcmp("-v", *argv) || !strcmp("--version",*argv)) {
      /* This write to the terminal is OK, it comes before we turn into a daemon */
      printf("chronyd (chrony) version %s (%s)\n", CHRONY_VERSION, CHRONYD_FEATURES);
      return 0;
    } else if (!strcmp("-n", *argv)) {
      nofork = 1;
    } else if (!strcmp("-d", *argv)) {
      debug++;
      nofork = 1;
      system_log = 0;
    } else if (!strcmp("-q", *argv)) {
      ref_mode = REF_ModeUpdateOnce;
      nofork = 1;
      system_log = 0;
    } else if (!strcmp("-Q", *argv)) {
      ref_mode = REF_ModePrintOnce;
      nofork = 1;
      system_log = 0;
    } else if (!strcmp("-t", *argv)) {
      ++argv, --argc;
      if (argc == 0 || sscanf(*argv, "%d", &timeout) != 1 || timeout <= 0)
        LOG_FATAL(LOGF_Main, "Bad timeout");
    } else if (!strcmp("-4", *argv)) {
      address_family = IPADDR_INET4;
    } else if (!strcmp("-6", *argv)) {
      address_family = IPADDR_INET6;
    } else if (!strcmp("-h", *argv) || !strcmp("--help", *argv)) {
      printf("Usage: %s [-4|-6] [-n|-d] [-q|-Q] [-r] [-R] [-s] [-t TIMEOUT] [-f FILE|COMMAND...]\n",
             progname);
      return 0;
    } else if (*argv[0] == '-') {
      LOG_FATAL(LOGF_Main, "Unrecognized command line option [%s]", *argv);
    } else {
      /* Process remaining arguments and configuration lines */
      config_args = argc;
      break;
    }
  }

  if (getuid() != 0) {
    /* This write to the terminal is OK, it comes before we turn into a daemon */
    fprintf(stderr,"Not superuser\n");
    return 1;
  }

  /* Turn into a daemon */
  if (!nofork) {
    go_daemon();
  }

  if (system_log) {
    LOG_OpenSystemLog();
  }
  
  LOG_SetDebugLevel(debug);
  
  LOG(LOGS_INFO, LOGF_Main, "chronyd version %s starting (%s)",
      CHRONY_VERSION, CHRONYD_FEATURES);

  DNS_SetAddressFamily(address_family);

  CNF_Initialise(restarted);

  /* Parse the config file or the remaining command line arguments */
  if (!config_args) {
    CNF_ReadFile(conf_file);
  } else {
    do {
      CNF_ParseLine(NULL, config_args - argc + 1, *argv);
    } while (++argv, --argc);
  }

  /* Check whether another chronyd may already be running.  Do this after
   * forking, so that message logging goes to the right place (i.e. syslog), in
   * case this chronyd is being run from a boot script. */
  if (maybe_another_chronyd_running(&other_pid)) {
    LOG_FATAL(LOGF_Main, "Another chronyd may already be running (pid=%d), check lockfile (%s)",
              other_pid, CNF_GetPidFile());
  }

  /* Write our lockfile to prevent other chronyds running.  This has *GOT* to
   * be done *AFTER* the daemon-creation fork() */
  write_lockfile();

  PRV_Initialise();
  LCL_Initialise();
  SCH_Initialise();
  SYS_Initialise();
  RTC_Initialise(do_init_rtc);
  SRC_Initialise();
  RCL_Initialise();
  KEY_Initialise();

  /* Open privileged ports before dropping root */
  CAM_Initialise(address_family);
  NIO_Initialise(address_family);
  NCR_Initialise();
  CNF_SetupAccessRestrictions();

  /* Command-line switch must have priority */
  if (!sched_priority) {
    sched_priority = CNF_GetSchedPriority();
  }
  if (sched_priority) {
    SYS_SetScheduler(sched_priority);
  }

  if (lock_memory || CNF_GetLockMemory()) {
    SYS_LockMemory();
  }

  if (!user) {
    user = CNF_GetUser();
  }

  if ((pw = getpwnam(user)) == NULL)
    LOG_FATAL(LOGF_Main, "Could not get %s uid/gid", user);

  /* Create all directories before dropping root */
  CNF_CreateDirs(pw->pw_uid, pw->pw_gid);

  /* Drop root privileges if the user has non-zero uid or gid */
  if (pw->pw_uid || pw->pw_gid)
    SYS_DropRoot(pw->pw_uid, pw->pw_gid);

  REF_Initialise();
  SST_Initialise();
  NSR_Initialise();
  NSD_Initialise();
  CLG_Initialise();
  MNL_Initialise();
  TMC_Initialise();
  SMT_Initialise();

  /* From now on, it is safe to do finalisation on exit */
  initialised = 1;

  UTI_SetQuitSignalsHandler(signal_cleanup);

  CAM_OpenUnixSocket();

  if (scfilter_level)
    SYS_EnableSystemCallFilter(scfilter_level);

  if (ref_mode == REF_ModeNormal && CNF_GetInitSources() > 0) {
    ref_mode = REF_ModeInitStepSlew;
  }

  REF_SetModeEndHandler(reference_mode_end);
  REF_SetMode(ref_mode);

  if (timeout)
    SCH_AddTimeoutByDelay(timeout, quit_timeout, NULL);

  if (do_init_rtc) {
    RTC_TimeInit(post_init_rtc_hook, NULL);
  } else {
    post_init_rtc_hook(NULL);
  }

  /* The program normally runs under control of the main loop in
     the scheduler. */
  SCH_MainLoop();

  LOG(LOGS_INFO, LOGF_Main, "chronyd exiting");

  MAI_CleanupAndExit();

  return 0;
}

/* ================================================== */