File: downtimed.c

package info (click to toggle)
downtimed 0.6-4
  • links: PTS, VCS
  • area: main
  • in suites: jessie, jessie-kfreebsd
  • size: 592 kB
  • ctags: 177
  • sloc: sh: 1,447; ansic: 893; xml: 45; makefile: 18
file content (910 lines) | stat: -rw-r--r-- 21,009 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
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
/*-
 * Copyright (c) 2009-2013 EPIPE Communications. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The views and conclusions contained in the software and documentation are
 * those of the authors and should not be interpreted as representing official
 * policies, either expressed or implied, of EPIPE Communications.
 *
 *
 * Software web site:
 *   http://dist.epipe.com/downtimed/
 *
 * Author contact information:
 *   opensource@epipe.com
 */

/* Include config.h in case we use autoconf. */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

/*
 * _GNU_SOURCE is required to enable in asprintf() and vasprintf()
 * in <stdio.h> on GNU/Linux.
 *
 * _BSD_SOURCE is required to enable BSD style signal(3) facility
 * on GNU/Linux.
 */

#if defined(__linux__) || defined(__GLIBC__) || defined(__GNU__)
/* GNU/Linux, GNU/kFreeBSD, and GNU/Hurd */
#define	_GNU_SOURCE
#define	_BSD_SOURCE
#endif

/*
 * Pull in facilitynames array if <syslog.h> has it.
 */

#ifdef HAVE_SYSLOG_FACILITYNAMES
#define	SYSLOG_NAMES
#endif

/* Standard includes that we need */

#include <sys/file.h>
#include <sys/stat.h>
#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#ifdef HAVE_SYS_SYSCTL_H
#include <sys/sysctl.h>
#endif
#include <sys/time.h>
#include <sys/types.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#ifdef HAVE_PATHS_H
#include <paths.h>
#endif
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <time.h>
#include <unistd.h>
#if defined(__SVR4) && defined(HAVE_UTMPX_H)
#include <utmpx.h>
#endif
#include <syslog.h>

#include "downtimedb.h"

/* Some global defines */

#define	PROGNAME "downtimed"

/* PACKAGE_VERSION is defined by autoconf, if used. */
#ifdef PACKAGE_VERSION
#define	PROGVERSION PACKAGE_VERSION
#else
#define	PROGVERSION "0.0undef"
#endif

/* We expect the following preprocessor macros to be defined */

/* from <paths.h> */

#ifndef _PATH_VARRUN
#define	_PATH_VARRUN	"/var/run/"
#endif

#ifndef _PATH_DEVNULL
#define	_PATH_DEVNULL	"/dev/null"
#endif

/* from <sys/stat.h> */

#ifndef DEFFILEMODE
#define	DEFFILEMODE 0666
#endif

/* Function prototypes */

int		main(int, char *[]);
static time_t	getboottime(void);
static void	updatedowntimedb(time_t, int, time_t);
static void	report(void);
static void	sighandler(int);
static void	touch(const char *, time_t);
static void	loginit(void);
static void	logdeinit(void);
static void	logwr(int, const char *, ...);
static void	version(void);
static void	usage(void);
static void	parseargs(int, char *[]);
static int	makepidfile(void);
static void	removepidfile(void);

#ifndef HAVE_DAEMON
static int	daemon(int, int);
#endif

/* Command line arguments with their defaults */

static char *	cf_log = "daemon";    /* syslog facility or filename with / */
static char *	cf_pidfile = _PATH_VARRUN PROGNAME ".pid";
static char *	cf_datadir = PATH_DOWNTIMEDBDIR;
static long	cf_sleep = 15;        /* update time stamp every 15 seconds */
#ifdef HAVE_FUTIMES
static int	cf_fsync = 1;  /* set to fsync() stamp files after touching */
#endif
static int	cf_downtimedb = 1;            /* if true, update downtimedb */
static char *	cf_downtimedbfile = PATH_DOWNTIMEDBFILE;
static char *	cf_timefmt = FMT_DATETIME;

/* Logging destination, determined from cf_log */

static int	cf_logfacility	=  0;
static int	cf_logfd	= -1;

/* Global variables */

static char *	ts_stamp	= NULL;
static char *	ts_shutdown	= NULL;
static char *	ts_boot		= NULL;
static time_t	boottime	= 0;
static time_t	starttime	= 0;

/* The following are set by the signal handler */

static volatile sig_atomic_t	exiting	  = 0;
static volatile sig_atomic_t	reopenlog = 0;

/*
 * downtimed: system downtime monitoring and reporting daemon.
 *
 * This daemon sits in the background, periodically updating a time stamp
 * on the disk. If the daemon is killed with a signal associated with a
 * normal system shutdown procedure, it will record the shutdown time on
 * the disk. When the daemon is restarted during the next boot process,
 * it will report how long the system was down and whether it was properly
 * shut down or crashed.
 */

int
main(int argc, char *argv[])
{
	struct stat sb;
	time_t uptime;

	/* record daemon startup time for later use */
	starttime = time((time_t *)NULL);

	/* parse command line arguments */
	parseargs(argc, argv);

	/* protect our files from tampering by other users */
	umask(S_IWGRP | S_IWOTH);

	/* initialize logging subsystem */
	loginit();

	/* find out system boot time */
	boottime = getboottime();

	/* check if datadir exists */
	if (stat(cf_datadir, &sb) < 0 || !S_ISDIR(sb.st_mode)) {
		logwr(LOG_CRIT, "data directory %s does not exist", cf_datadir);
		errx(EX_CANTCREAT, "data directory %s does not exist",
		    cf_datadir);
	}

	/* set time stamp file names */
	if (asprintf(&ts_stamp, "%s/downtimed.stamp", cf_datadir) < 0 ||
	    asprintf(&ts_shutdown, "%s/downtimed.shutdown", cf_datadir) < 0
	    || asprintf(&ts_boot, "%s/downtimed.boot", cf_datadir) < 0) {
		logwr(LOG_CRIT, "asprintf failed, out of memory?");
		errx(EX_OSERR, "asprintf failed, out of memory?");
	}

#ifndef __APPLE__  /* under Mac OS X, use launchd(8) */
	/* run as daemon (fork and detach from controlling tty) */
	if (daemon(0, 0) < 0) {
		logwr(LOG_CRIT, "starting daemon failed: %s", strerror(errno));
		err(EX_OSERR, "starting daemon failed");
	}
#endif

	/* create pid file */
	if (makepidfile() < 0) {
		/* the error has been logged already in makepidfile() */
		exit(EX_UNAVAILABLE);
	}

	/* check & log startup status */
	report();

	/* set up the signal handlers */
	signal(SIGHUP, sighandler);
	signal(SIGINT, sighandler);
	signal(SIGTERM, sighandler);

	/* touch system boot time */
	touch(ts_boot, boottime);

	/*
	 * main loop: run until we receive a signal or system dies,
         * touching the time stamp file regularly
	 */
	while (exiting == 0) {
		touch(ts_stamp, 0);
		sleep(cf_sleep);

		if (reopenlog) {
			reopenlog = 0;
			logdeinit();
			loginit();
		}
	}

	/*
	 * Record normal shutdown. If using syslog for logging, this
	 * might fail because syslogd may have exited already.
	 */
	uptime = time((time_t *)NULL) - boottime;
	logwr(LOG_NOTICE, "shutting down, uptime %s (%d seconds)",
	    timestr_int(uptime), uptime);

	touch(ts_stamp, 0);
	touch(ts_shutdown, 0);

	/* We could write the downtime database shutdown record here
	 * in case of graceful shutdown, but we have chosen to update
	 * it consistently only at the program start.
	 */

	logdeinit();
	removepidfile();

	exit(EX_OK);
}

/* Find out system boot time */

static time_t
getboottime()
{
#if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) \
    || defined(__DragonFly__) || defined(__APPLE__) \
    || defined(__FreeBSD_kernel__)
	/*
	 * BSDish systems have the boot time available through sysctl.
	 */
	int mib[2];
	struct timeval bt;
	size_t btsize;

	mib[0] = CTL_KERN;
	mib[1] = KERN_BOOTTIME;
	btsize = sizeof(bt);

	if (sysctl(mib, 2, &bt, &btsize, (void *)NULL, 0) != -1 &&
	    bt.tv_sec != 0)
		return (bt.tv_sec);

#elif defined(__linux__)
	/*
	 * Linux systems have the boot time available through /proc filesystem.
	 */
	char str[1024];
	FILE *fp;
	long unsigned bt = 0;

	if ((fp = fopen("/proc/stat", "r")) != NULL) {
		while (fgets(str, sizeof(str), fp) != NULL)
			if (strncmp(str, "btime ", 6) == 0)
				if (sscanf(str, "btime %lu", &bt) == 1 &&
				    bt != 0) {
					fclose(fp);
					return ((time_t)bt);
				}
		fclose(fp);
	}
#elif defined(__SVR4) && defined(HAVE_UTMPX_H)
	/*
	 * This should work on some SVR4 systems, such as Solaris
	 * and possibly HP-UX.
	 */
	struct utmpx ut, *utp;

	memset(&ut, 0, sizeof(ut));
	ut.ut_type = BOOT_TIME;
	if ((utp = getutxid(&ut)) != NULL) {
		time_t boottime;

		boottime = utp->ut_tv.tv_sec;
		endutxent();

		return (boottime);
	}
	endutxent();
#endif
	/*
	 * We fall through here if we do not have OS specific code
	 * implemented or if the OS specific code fails.
	 *
	 * The logic could be improved to stat() some files which are
	 * accessed or modified early at system startup (for example the
	 * system log, dmesg.boot, kernel, utmp, etc.) XXX
	 */

	logwr(LOG_ERR, "can not determine system boot time on this OS");

	return (starttime);	/* give up */
}

/* Update downtime database */

void
updatedowntimedb(time_t up, int crashed, time_t down)
{
	struct downtimedb dbent;
	int fd;

	if ((fd = open(cf_downtimedbfile, O_WRONLY | O_CREAT | O_APPEND,
	    DEFFILEMODE)) < 0) {
		logwr(LOG_ERR, "can not open %s: %s", cf_downtimedbfile,
		    strerror(errno));
		return;
	}

	/* ensure that padding bytes are zero */
	memset(&dbent, 0, sizeof(struct downtimedb));

	dbent.what = crashed ?
	    DOWNTIMEDB_WHAT_CRASH : DOWNTIMEDB_WHAT_SHUTDOWN;
	dbent.when = (uint64_t) down;

	if (downtimedb_write(fd, &dbent) < 0)
		logwr(LOG_ERR, "can not write to %s: %s", cf_downtimedbfile,
		    strerror(errno));

	/* not really needed, but ensure again that padding bytes are zero */
	memset(&dbent, 0, sizeof(struct downtimedb));

	dbent.what = DOWNTIMEDB_WHAT_UP;
	dbent.when = (uint64_t) up;

	if (downtimedb_write(fd, &dbent) < 0)
		logwr(LOG_ERR, "can not write to %s: %s", cf_downtimedbfile,
		    strerror(errno));

	close(fd);
}

/* Report the downtime and shutdown reason when starting up */

static void
report()
{
	struct stat sb_stamp, sb_shutdown, sb_oldboot;
	int have_stamp = 0, have_shutdown = 0, have_oldboot = 0;
	time_t olduptime, downtime;

	if (stat(ts_stamp, &sb_stamp) == 0)
		have_stamp = 1;

	if (stat(ts_shutdown, &sb_shutdown) == 0)
		have_shutdown = 1;

	if (stat(ts_boot, &sb_oldboot) == 0)
		have_oldboot = 1;

	if (!have_stamp && !have_shutdown && !have_oldboot) {
		logwr(LOG_NOTICE, "starting up first time, "
		    "no knowledge of downtime");
		return;
	}
	if (!have_stamp) {
		logwr(LOG_ERR, "no old run-time stamp (%s)", ts_stamp);
		return;
	}
	if (!have_oldboot) {
		logwr(LOG_ERR, "no old boot-time stamp (%s)", ts_boot);
		return;
	}
	if (have_stamp && have_shutdown &&
	    sb_shutdown.st_mtime < sb_stamp.st_mtime)
		have_shutdown = 0;

	olduptime =
	    (have_shutdown ? sb_shutdown.st_mtime : sb_stamp.st_mtime) -
	    sb_oldboot.st_mtime;

	downtime = boottime -
	    (have_shutdown ? sb_shutdown.st_mtime : sb_stamp.st_mtime);

	if (downtime < 0) {
		/*
		 * This happens if we quit and re-start the process (we
		 * normally only exit when system goes down.
		 */
		logwr(LOG_NOTICE, "restarted, system was not down");
		return;
	}

	logwr(LOG_NOTICE, "started %d seconds after boot",
	    starttime - boottime);

	if (cf_downtimedb)
		updatedowntimedb(boottime, !have_shutdown,
		    (have_shutdown ?
		    sb_shutdown.st_mtime : sb_stamp.st_mtime));

	if (have_shutdown) {
		logwr(LOG_NOTICE, "system shutdown at %s",
		    timestr_abs(sb_shutdown.st_mtime, cf_timefmt, 0));
	} else {
		logwr(LOG_NOTICE, "system crashed at %s",
		    timestr_abs(sb_stamp.st_mtime, cf_timefmt, 0));
	}

	logwr(LOG_NOTICE, "previous uptime was %s (%d seconds)",
	    timestr_int(olduptime), olduptime);

	logwr(LOG_NOTICE, "downtime was %s (%d seconds)",
	    timestr_int(downtime), downtime);
}

/* Handle signals */

static void
sighandler(int signum)
{

	if (signum == SIGINT || signum == SIGTERM)
		exiting = 1;

	if (signum == SIGHUP)
		reopenlog = 1;
}

/* Update time-stamp of file */

static void
touch(const char *fn, time_t t)
{
	struct stat sb;
	struct timeval tv[2];
	int fd;

	if (t != 0) {
		tv[0].tv_sec = t;
		tv[0].tv_usec = 0;
		tv[1].tv_sec = t;
		tv[1].tv_usec = 0;
	}

#ifdef HAVE_FUTIMES
	if (cf_fsync) {
		/* we need to open the file so that we can do fsync() to it */
		if ((fd = open(fn, O_WRONLY | O_CREAT | O_TRUNC,
		    DEFFILEMODE)) < 0) {
			logwr(LOG_ERR, "%s: %s", fn, strerror(errno));
			return;
		}
		if (futimes(fd, t == 0 ? (struct timeval *)NULL : tv) < 0) {
			logwr(LOG_ERR, "%s: %s", fn, strerror(errno));
		} else
			fsync(fd);

		if (close(fd) < 0)
			logwr(LOG_ERR, "%s: %s", fn, strerror(errno));
	} else {
#endif /* HAVE_FUTIMES */
		/* create the file in case it is missing */
		if (stat(fn, &sb) < 0) {
			if ((fd = open(fn, O_WRONLY | O_CREAT | O_TRUNC,
			    DEFFILEMODE)) < 0) {
				logwr(LOG_ERR, "%s: %s", fn, strerror(errno));
				return;
			}
			if (close(fd) < 0)
				logwr(LOG_ERR, "%s: %s", fn, strerror(errno));
		}
		if (utimes(fn, t == 0 ? (struct timeval *)NULL : tv) < 0)
			logwr(LOG_ERR, "%s: %s", fn, strerror(errno));
#ifdef HAVE_FUTIMES
	}
#endif /* HAVE_FUTIMES */
}

/* Compatibility for systems without facilitynames in <syslog.h> */

#ifndef HAVE_SYSLOG_FACILITYNAMES

static const struct {
	const char	*c_name;
	const int	c_val;
} facilitynames[] = {
#ifdef LOG_KERN
	{ "kern",	LOG_KERN	},
#endif
#ifdef LOG_USER
	{ "user",	LOG_USER	},
#endif
#ifdef LOG_MAIL
	{ "mail",	LOG_MAIL	},
#endif
#ifdef LOG_DAEMON
	{ "daemon",	LOG_DAEMON	},
#endif
#ifdef LOG_AUTH
	{ "auth",	LOG_AUTH	},
#endif
#ifdef LOG_SYSLOG
	{ "syslog",	LOG_SYSLOG	},
#endif
#ifdef LOG_LPR
	{ "lpr",	LOG_LPR		},
#endif
#ifdef LOG_NEWS
	{ "news",	LOG_NEWS	},
#endif
#ifdef LOG_AUDIT
	{ "audit",	LOG_AUDIT	},
#endif
#ifdef LOG_CRON
	{ "cron",	LOG_CRON	},
#endif
#ifdef LOG_LOCAL0
	{ "local0",	LOG_LOCAL0	},
#endif
#ifdef LOG_LOCAL1
	{ "local1",	LOG_LOCAL1	},
#endif
#ifdef LOG_LOCAL2
	{ "local2",	LOG_LOCAL2	},
#endif
#ifdef LOG_LOCAL3
	{ "local3",	LOG_LOCAL3	},
#endif
#ifdef LOG_LOCAL4
	{ "local4",	LOG_LOCAL4	},
#endif
#ifdef LOG_LOCAL5
	{ "local5",	LOG_LOCAL5	},
#endif
#ifdef LOG_LOCAL6
	{ "local6",	LOG_LOCAL6	},
#endif
#ifdef LOG_LOCAL7
	{ "local7",	LOG_LOCAL7	},
#endif
	{ NULL,		-1		}
};


#endif /* !defined(HAVE_SYSLOG_FACILITYNAMES) */

/* Determine log destination & initialize */

static void
loginit()
{
	int i;

	if (strchr(cf_log, '/') == NULL) {
		/* Logging to syslog if there is no slash in the name. */

		for(i = 0; facilitynames[i].c_name != NULL; i++)
			if (strcmp(facilitynames[i].c_name, cf_log) == 0)
			    cf_logfacility = facilitynames[i].c_val;

		if (cf_logfacility == 0)
			errx(EX_USAGE,
			    "-l argument is not syslog facility or file path");

		openlog(PROGNAME, LOG_PID, cf_logfacility);
	} else {
		/* We are logging to a file. */

		if ((cf_logfd = open(cf_log, O_WRONLY | O_APPEND | O_CREAT,
		    DEFFILEMODE)) < 0)
			err(EX_CANTCREAT, "%s", cf_log);
	}
}

/* De-initialize & close logging */

static void
logdeinit()
{

	if (cf_logfd < 0) {
		closelog();
	} else {
		close(cf_logfd);
		cf_logfd = -1;
	}
}

/* Log a message */

static void
logwr(int pri, const char *fmt, ...)
{
	char *str, *str2;

	va_list ap;

	va_start(ap, fmt);

	if (cf_logfd < 0) {
		vsyslog(pri, fmt, ap);
	} else {
		if (vasprintf(&str, fmt, ap) < 0)
			goto err;

		if (asprintf(&str2, "%s: %s\n",
		    timestr_abs(time((time_t *) NULL), cf_timefmt, 0), str)
		    < 0) {
			free(str);
			goto err;
		}

		/*
		 * Write a log entry to log file. We do not do any error
		 * checking because there is not much we can do if logging
		 * fails (most likely due to disk full situation) as we
		 * can not log the error. Even if logging fails, it still
		 * makes sense to keep running and updating timestamps.
		 */
		if (write(cf_logfd, str2, strlen(str2)) < 0)
			/* do nothing but keep compiler happy */
			;

		free(str2);
		free(str);
	}
err:
	va_end(ap);
}

/* Usage help & exit */

static void
usage()
{

	fputs("usage: " PROGNAME " [-DvS] [-d datadir] [-f timefmt] "
	    "[-l log] [-p pidfile] [-s sleep]\n", stderr);
	exit(EX_USAGE);
}

/* Output version information, default settings & exit */

static void
version()
{

	puts(PROGNAME " " PROGVERSION " - system downtime reporting daemon\n");

	puts("Copyright (c) 2009-2013 EPIPE Communications. "
	    "All rights reserved.");
	puts("This software is licensed under the terms and conditions of the "
	    "FreeBSD");
	puts("License which is also known as the Simplified BSD License. You "
	    "should have ");
	puts("received a copy of that license along with this software.\n");

	puts("Default settings:");
	printf("  log = %s\n", cf_log);
	printf("  pidfile = %s\n", cf_pidfile);
	printf("  datadir = %s\n", cf_datadir);
	printf("  downtimedbfile = %s\n", cf_downtimedbfile);
	printf("  sleep = %ld\n", cf_sleep);
#ifdef HAVE_FUTIMES
	printf("  fsync = %d\n", cf_fsync);
#endif

#ifdef PACKAGE_URL
	puts("\nSee the following web site for more information and updates:");
	puts("  " PACKAGE_URL "\n");
#endif
	exit(EX_OK);
}

/* Handle command line arguments */

static void
parseargs(int argc, char *argv[])
{
	int c;
	char *p;

	while ((c = getopt(argc, argv, "Dd:f:l:p:s:Svh?")) != -1) {
		switch (c) {
		case 'D':
			cf_downtimedb = 0;
			break;
		case 'd':
			cf_datadir = optarg;
			break;
		case 'f':
			cf_timefmt = optarg;
			break;
		case 'l':
			cf_log = optarg;
			break;
		case 'p':
			cf_pidfile = optarg;
			break;
		case 's':
			p = NULL;
			errno = 0;
			cf_sleep = strtol(optarg, &p, 10);
			if ((p != NULL && *p != '\0') || errno != 0)
				errx(EX_USAGE, "-s argument is not a number");
			break;
		case 'S':
#ifdef HAVE_FUTIMES
			cf_fsync = 0;
#endif
			break;
		case 'v':
			version();
			/* NOTREACHED */
			break;
		case 'h':
		case '?':
		default:
			usage();
			/* NOTREACHED */
			break;
		}
	}
	if (argc != optind)
		usage();
}

/*
 * Create a pid file, return -1 on error. This is loosely based on
 * FreeBSD flopen.c.
 */

static int
makepidfile()
{
	char str[100];
	struct stat sb, sb2;
	int fd;

retry:
	if ((fd = open(cf_pidfile, O_WRONLY | O_CREAT, DEFFILEMODE)) < 0) {
		logwr(LOG_ERR, "can not open pid file %s: %s",
		    cf_pidfile, strerror(errno));
		return (-1);
	}
#ifdef HAVE_FLOCK
	if (flock(fd, LOCK_EX | LOCK_NB) < 0) {
#else
	if (lockf(fd, F_TLOCK, 0) < 0) {
#endif
		if (errno == EWOULDBLOCK || errno == EAGAIN || errno == EACCES)
			logwr(LOG_ERR, "another process is running already");
		else
			logwr(LOG_ERR, "can not lock pid file %s: %s",
			    cf_pidfile, strerror(errno));
		close(fd);
		return (-1);
	}
	if (stat(cf_pidfile, &sb) < 0) {
		/* disappeared from under our feet */
		close(fd);
		goto retry;
	}
	if (fstat(fd, &sb2) < 0) {
		/* can not happen :) */
		logwr(LOG_ERR, "can not fstat pid file %s: %s",
		    cf_pidfile, strerror(errno));
		close(fd);
		return (-1);
	}
	if (sb.st_dev != sb2.st_dev || sb.st_ino != sb2.st_ino) {
		/* changed under our feet */
		close(fd);
		goto retry;
	}
	if (ftruncate(fd, 0) < 0) {
		/* should not happen */
		logwr(LOG_ERR, "can not ftruncate pid file %s: %s",
			cf_pidfile, strerror(errno));
		close(fd);
		return (-1);
	}
	snprintf(str, sizeof(str), "%ld\n", (long)getpid());
	if (write(fd, str, strlen(str)) != strlen(str)) {
		logwr(LOG_ERR, "can not write pid file %s: %s",
		    cf_pidfile, strerror(errno));
		close(fd);
		return (-1);
	}

	/*
	 * NOTE: we leave the file open (although we can not access the
	 * file descriptor any more) so that we can retain the lock as
	 * long as the process is alive.
	 */

	return (0);
}

/* Remove pid file */

static void
removepidfile()
{

	/*
	 * We are not releasing the lock. We still have an open
	 * file descriptor to the unlink()ed file, but that is sorted
	 * out when we exit shortly after calling this function.
	 */

	unlink(cf_pidfile);
}

/* Compatibility daemon(3) function for OSes which lack it */

#ifndef HAVE_DAEMON
static int
daemon(int nochdir, int noclose)
{
	int fd;

	switch (fork()) {
	case -1:
		return (-1);
	case 0:
		break;
	default:
		exit(0);
	}

	if (setsid() == -1)
		return (-1);

	if (!nochdir)
		chdir("/");

	if (!noclose && (fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
		dup2(fd, STDIN_FILENO);
		dup2(fd, STDOUT_FILENO);
		dup2(fd, STDERR_FILENO);
		if (fd > STDERR_FILENO)
			close(fd);
	}
	return (0);
}
#endif /* !HAVE_DAEMON */

/* eof */