aboutsummaryrefslogtreecommitdiffstats
path: root/cmd/zed/zed_event.c
blob: 940172bc38dfab3f6ba4ece47c5061a836a32d07 (plain)
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
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license from the top-level
 * OPENSOLARIS.LICENSE or <http://opensource.org/licenses/CDDL-1.0>.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each file
 * and include the License file from the top-level OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Developed at Lawrence Livermore National Laboratory (LLNL-CODE-403049).
 * Copyright (C) 2013-2014 Lawrence Livermore National Security, LLC.
 */

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <libzfs.h>			/* FIXME: Replace with libzfs_core. */
#include <paths.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/zfs_ioctl.h>
#include <time.h>
#include <unistd.h>
#include "zed.h"
#include "zed_conf.h"
#include "zed_exec.h"
#include "zed_file.h"
#include "zed_log.h"
#include "zed_strings.h"

/*
 * Open the libzfs interface.
 */
void
zed_event_init(struct zed_conf *zcp)
{
	if (!zcp)
		zed_log_die("Failed zed_event_init: %s", strerror(EINVAL));

	zcp->zfs_hdl = libzfs_init();
	if (!zcp->zfs_hdl)
		zed_log_die("Failed to initialize libzfs");

	zcp->zevent_fd = open(ZFS_DEV, O_RDWR);
	if (zcp->zevent_fd < 0)
		zed_log_die("Failed to open \"%s\": %s",
		    ZFS_DEV, strerror(errno));
}

/*
 * Close the libzfs interface.
 */
void
zed_event_fini(struct zed_conf *zcp)
{
	if (!zcp)
		zed_log_die("Failed zed_event_fini: %s", strerror(EINVAL));

	if (zcp->zevent_fd >= 0) {
		if (close(zcp->zevent_fd) < 0)
			zed_log_msg(LOG_WARNING, "Failed to close \"%s\": %s",
			    ZFS_DEV, strerror(errno));

		zcp->zevent_fd = -1;
	}
	if (zcp->zfs_hdl) {
		libzfs_fini(zcp->zfs_hdl);
		zcp->zfs_hdl = NULL;
	}
}

/*
 * Seek to the event specified by [saved_eid] and [saved_etime].
 * This protects against processing a given event more than once.
 * Return 0 upon a successful seek to the specified event, or -1 otherwise.
 *
 * A zevent is considered to be uniquely specified by its (eid,time) tuple.
 * The unsigned 64b eid is set to 1 when the kernel module is loaded, and
 * incremented by 1 for each new event.  Since the state file can persist
 * across a kernel module reload, the time must be checked to ensure a match.
 */
int
zed_event_seek(struct zed_conf *zcp, uint64_t saved_eid, int64_t saved_etime[])
{
	uint64_t eid;
	int found;
	nvlist_t *nvl;
	int n_dropped;
	int64_t *etime;
	uint_t nelem;
	int rv;

	if (!zcp) {
		errno = EINVAL;
		zed_log_msg(LOG_ERR, "Failed to seek zevent: %s",
		    strerror(errno));
		return (-1);
	}
	eid = 0;
	found = 0;
	while ((eid < saved_eid) && !found) {
		rv = zpool_events_next(zcp->zfs_hdl, &nvl, &n_dropped,
		    ZEVENT_NONBLOCK, zcp->zevent_fd);

		if ((rv != 0) || !nvl)
			break;

		if (n_dropped > 0) {
			zed_log_msg(LOG_WARNING, "Missed %d events", n_dropped);
			/*
			 * FIXME: Increase max size of event nvlist in
			 *   /sys/module/zfs/parameters/zfs_zevent_len_max ?
			 */
		}
		if (nvlist_lookup_uint64(nvl, "eid", &eid) != 0) {
			zed_log_msg(LOG_WARNING, "Failed to lookup zevent eid");
		} else if (nvlist_lookup_int64_array(nvl, "time",
		    &etime, &nelem) != 0) {
			zed_log_msg(LOG_WARNING,
			    "Failed to lookup zevent time (eid=%llu)", eid);
		} else if (nelem != 2) {
			zed_log_msg(LOG_WARNING,
			    "Failed to lookup zevent time (eid=%llu, nelem=%u)",
			    eid, nelem);
		} else if ((eid != saved_eid) ||
		    (etime[0] != saved_etime[0]) ||
		    (etime[1] != saved_etime[1])) {
			/* no-op */
		} else {
			found = 1;
		}
		free(nvl);
	}
	if (!found && (saved_eid > 0)) {
		if (zpool_events_seek(zcp->zfs_hdl, ZEVENT_SEEK_START,
		    zcp->zevent_fd) < 0)
			zed_log_msg(LOG_WARNING, "Failed to seek to eid=0");
		else
			eid = 0;
	}
	zed_log_msg(LOG_NOTICE, "Processing events since eid=%llu", eid);
	return (found ? 0 : -1);
}

static int
_zed_event_convert_int8_array(char *buf, int buflen, nvpair_t *nvp)
{
	int8_t *i8p;
	uint_t nelem;
	uint_t i;
	char *p;
	int n;

	assert(buf != NULL);

	(void) nvpair_value_int8_array(nvp, &i8p, &nelem);
	for (i = 0, p = buf; (i < nelem) && (buflen > 0); i++) {
		n = snprintf(p, buflen, "%d ", i8p[i]);
		if ((n < 0) || (n >= buflen)) {
			*buf = '\0';
			return (-1);
		}
		p += n;
		buflen -= n;
	}
	if (nelem > 0)
		*--p = '\0';

	return (p - buf);
}

static int
_zed_event_convert_uint8_array(char *buf, int buflen, nvpair_t *nvp)
{
	uint8_t *u8p;
	uint_t nelem;
	uint_t i;
	char *p;
	int n;

	assert(buf != NULL);

	(void) nvpair_value_uint8_array(nvp, &u8p, &nelem);
	for (i = 0, p = buf; (i < nelem) && (buflen > 0); i++) {
		n = snprintf(p, buflen, "%u ", u8p[i]);
		if ((n < 0) || (n >= buflen)) {
			*buf = '\0';
			return (-1);
		}
		p += n;
		buflen -= n;
	}
	if (nelem > 0)
		*--p = '\0';

	return (p - buf);
}

static int
_zed_event_convert_int16_array(char *buf, int buflen, nvpair_t *nvp)
{
	int16_t *i16p;
	uint_t nelem;
	uint_t i;
	char *p;
	int n;

	assert(buf != NULL);

	(void) nvpair_value_int16_array(nvp, &i16p, &nelem);
	for (i = 0, p = buf; (i < nelem) && (buflen > 0); i++) {
		n = snprintf(p, buflen, "%d ", i16p[i]);
		if ((n < 0) || (n >= buflen)) {
			*buf = '\0';
			return (-1);
		}
		p += n;
		buflen -= n;
	}
	if (nelem > 0)
		*--p = '\0';

	return (p - buf);
}

static int
_zed_event_convert_uint16_array(char *buf, int buflen, nvpair_t *nvp)
{
	uint16_t *u16p;
	uint_t nelem;
	uint_t i;
	char *p;
	int n;

	assert(buf != NULL);

	(void) nvpair_value_uint16_array(nvp, &u16p, &nelem);
	for (i = 0, p = buf; (i < nelem) && (buflen > 0); i++) {
		n = snprintf(p, buflen, "%u ", u16p[i]);
		if ((n < 0) || (n >= buflen)) {
			*buf = '\0';
			return (-1);
		}
		p += n;
		buflen -= n;
	}
	if (nelem > 0)
		*--p = '\0';

	return (p - buf);
}

static int
_zed_event_convert_int32_array(char *buf, int buflen, nvpair_t *nvp)
{
	int32_t *i32p;
	uint_t nelem;
	uint_t i;
	char *p;
	int n;

	assert(buf != NULL);

	(void) nvpair_value_int32_array(nvp, &i32p, &nelem);
	for (i = 0, p = buf; (i < nelem) && (buflen > 0); i++) {
		n = snprintf(p, buflen, "%d ", i32p[i]);
		if ((n < 0) || (n >= buflen)) {
			*buf = '\0';
			return (-1);
		}
		p += n;
		buflen -= n;
	}
	if (nelem > 0)
		*--p = '\0';

	return (p - buf);
}

static int
_zed_event_convert_uint32_array(char *buf, int buflen, nvpair_t *nvp)
{
	uint32_t *u32p;
	uint_t nelem;
	uint_t i;
	char *p;
	int n;

	assert(buf != NULL);

	(void) nvpair_value_uint32_array(nvp, &u32p, &nelem);
	for (i = 0, p = buf; (i < nelem) && (buflen > 0); i++) {
		n = snprintf(p, buflen, "%u ", u32p[i]);
		if ((n < 0) || (n >= buflen)) {
			*buf = '\0';
			return (-1);
		}
		p += n;
		buflen -= n;
	}
	if (nelem > 0)
		*--p = '\0';

	return (p - buf);
}

static int
_zed_event_convert_int64_array(char *buf, int buflen, nvpair_t *nvp)
{
	int64_t *i64p;
	uint_t nelem;
	uint_t i;
	char *p;
	int n;

	assert(buf != NULL);

	(void) nvpair_value_int64_array(nvp, &i64p, &nelem);
	for (i = 0, p = buf; (i < nelem) && (buflen > 0); i++) {
		n = snprintf(p, buflen, "%lld ", (u_longlong_t) i64p[i]);
		if ((n < 0) || (n >= buflen)) {
			*buf = '\0';
			return (-1);
		}
		p += n;
		buflen -= n;
	}
	if (nelem > 0)
		*--p = '\0';

	return (p - buf);
}

static int
_zed_event_convert_uint64_array(char *buf, int buflen, nvpair_t *nvp,
    const char *fmt)
{
	uint64_t *u64p;
	uint_t nelem;
	uint_t i;
	char *p;
	int n;

	assert(buf != NULL);

	(void) nvpair_value_uint64_array(nvp, &u64p, &nelem);
	for (i = 0, p = buf; (i < nelem) && (buflen > 0); i++) {
		n = snprintf(p, buflen, fmt, (u_longlong_t) u64p[i]);
		if ((n < 0) || (n >= buflen)) {
			*buf = '\0';
			return (-1);
		}
		p += n;
		buflen -= n;
	}
	if (nelem > 0)
		*--p = '\0';

	return (p - buf);
}

static int
_zed_event_convert_string_array(char *buf, int buflen, nvpair_t *nvp)
{
	char **strp;
	uint_t nelem;
	uint_t i;
	char *p;
	int n;

	assert(buf != NULL);

	(void) nvpair_value_string_array(nvp, &strp, &nelem);
	for (i = 0, p = buf; (i < nelem) && (buflen > 0); i++) {
		n = snprintf(p, buflen, "%s ", strp[i] ? strp[i] : "<NULL>");
		if ((n < 0) || (n >= buflen)) {
			*buf = '\0';
			return (-1);
		}
		p += n;
		buflen -= n;
	}
	if (nelem > 0)
		*--p = '\0';

	return (p - buf);
}

/*
 * Return non-zero if nvpair [name] should be formatted in hex; o/w, return 0.
 */
static int
_zed_event_value_is_hex(const char *name)
{
	const char *hex_suffix[] = {
		"_guid",
		"_guids",
		NULL
	};
	const char **pp;
	char *p;

	if (!name)
		return (0);

	for (pp = hex_suffix; *pp; pp++) {
		p = strstr(name, *pp);
		if (p && strlen(p) == strlen(*pp))
			return (1);
	}
	return (0);
}

/*
 * Convert the nvpair [nvp] to a string which is added to the environment
 * of the child process.
 * Return 0 on success, -1 on error.
 *
 * FIXME: Refactor with cmd/zpool/zpool_main.c:zpool_do_events_nvprint()?
 */
static void
_zed_event_add_nvpair(uint64_t eid, zed_strings_t *zsp, nvpair_t *nvp)
{
	const char *name;
	data_type_t type;
	char buf[4096];
	int buflen;
	int n;
	char *p;
	const char *q;
	const char *fmt;

	boolean_t b;
	double d;
	uint8_t i8;
	uint16_t i16;
	uint32_t i32;
	uint64_t i64;
	char *str;

	assert(zsp != NULL);
	assert(nvp != NULL);

	name = nvpair_name(nvp);
	type = nvpair_type(nvp);
	buflen = sizeof (buf);

	/* Copy NAME prefix for ZED zevent namespace. */
	n = strlcpy(buf, ZEVENT_VAR_PREFIX, sizeof (buf));
	if (n >= sizeof (buf)) {
		zed_log_msg(LOG_WARNING,
		    "Failed to convert nvpair \"%s\" for eid=%llu: %s",
		    name, eid, "Exceeded buffer size");
		return;
	}
	buflen -= n;
	p = buf + n;

	/* Convert NAME to alphanumeric uppercase. */
	for (q = name; *q && (buflen > 0); q++) {
		*p++ = isalnum(*q) ? toupper(*q) : '_';
		buflen--;
	}

	/* Separate NAME from VALUE. */
	if (buflen > 0) {
		*p++ = '=';
		buflen--;
	}
	*p = '\0';

	/* Convert VALUE. */
	switch (type) {
	case DATA_TYPE_BOOLEAN:
		n = snprintf(p, buflen, "%s", "1");
		break;
	case DATA_TYPE_BOOLEAN_VALUE:
		(void) nvpair_value_boolean_value(nvp, &b);
		n = snprintf(p, buflen, "%s", b ? "1" : "0");
		break;
	case DATA_TYPE_BYTE:
		(void) nvpair_value_byte(nvp, &i8);
		n = snprintf(p, buflen, "%d", i8);
		break;
	case DATA_TYPE_INT8:
		(void) nvpair_value_int8(nvp, (int8_t *) &i8);
		n = snprintf(p, buflen, "%d", i8);
		break;
	case DATA_TYPE_UINT8:
		(void) nvpair_value_uint8(nvp, &i8);
		n = snprintf(p, buflen, "%u", i8);
		break;
	case DATA_TYPE_INT16:
		(void) nvpair_value_int16(nvp, (int16_t *) &i16);
		n = snprintf(p, buflen, "%d", i16);
		break;
	case DATA_TYPE_UINT16:
		(void) nvpair_value_uint16(nvp, &i16);
		n = snprintf(p, buflen, "%u", i16);
		break;
	case DATA_TYPE_INT32:
		(void) nvpair_value_int32(nvp, (int32_t *) &i32);
		n = snprintf(p, buflen, "%d", i32);
		break;
	case DATA_TYPE_UINT32:
		(void) nvpair_value_uint32(nvp, &i32);
		n = snprintf(p, buflen, "%u", i32);
		break;
	case DATA_TYPE_INT64:
		(void) nvpair_value_int64(nvp, (int64_t *) &i64);
		n = snprintf(p, buflen, "%lld", (longlong_t) i64);
		break;
	case DATA_TYPE_UINT64:
		(void) nvpair_value_uint64(nvp, &i64);
		fmt = _zed_event_value_is_hex(name) ? "0x%.16llX" : "%llu";
		n = snprintf(p, buflen, fmt, (u_longlong_t) i64);
		break;
	case DATA_TYPE_DOUBLE:
		(void) nvpair_value_double(nvp, &d);
		n = snprintf(p, buflen, "%g", d);
		break;
	case DATA_TYPE_HRTIME:
		(void) nvpair_value_hrtime(nvp, (hrtime_t *) &i64);
		n = snprintf(p, buflen, "%llu", (u_longlong_t) i64);
		break;
	case DATA_TYPE_NVLIST:
		/* FIXME */
		n = snprintf(p, buflen, "%s", "_NOT_IMPLEMENTED_");
		break;
	case DATA_TYPE_STRING:
		(void) nvpair_value_string(nvp, &str);
		n = snprintf(p, buflen, "%s", (str ? str : "<NULL>"));
		break;
	case DATA_TYPE_BOOLEAN_ARRAY:
		/* FIXME */
		n = snprintf(p, buflen, "%s", "_NOT_IMPLEMENTED_");
		break;
	case DATA_TYPE_BYTE_ARRAY:
		/* FIXME */
		n = snprintf(p, buflen, "%s", "_NOT_IMPLEMENTED_");
		break;
	case DATA_TYPE_INT8_ARRAY:
		n = _zed_event_convert_int8_array(p, buflen, nvp);
		break;
	case DATA_TYPE_UINT8_ARRAY:
		n = _zed_event_convert_uint8_array(p, buflen, nvp);
		break;
	case DATA_TYPE_INT16_ARRAY:
		n = _zed_event_convert_int16_array(p, buflen, nvp);
		break;
	case DATA_TYPE_UINT16_ARRAY:
		n = _zed_event_convert_uint16_array(p, buflen, nvp);
		break;
	case DATA_TYPE_INT32_ARRAY:
		n = _zed_event_convert_int32_array(p, buflen, nvp);
		break;
	case DATA_TYPE_UINT32_ARRAY:
		n = _zed_event_convert_uint32_array(p, buflen, nvp);
		break;
	case DATA_TYPE_INT64_ARRAY:
		n = _zed_event_convert_int64_array(p, buflen, nvp);
		break;
	case DATA_TYPE_UINT64_ARRAY:
		fmt = _zed_event_value_is_hex(name) ? "0x%.16llX " : "%llu ";
		n = _zed_event_convert_uint64_array(p, buflen, nvp, fmt);
		break;
	case DATA_TYPE_STRING_ARRAY:
		n = _zed_event_convert_string_array(p, buflen, nvp);
		break;
	case DATA_TYPE_NVLIST_ARRAY:
		/* FIXME */
		n = snprintf(p, buflen, "%s", "_NOT_IMPLEMENTED_");
		break;
	default:
		zed_log_msg(LOG_WARNING,
		    "Failed to convert nvpair \"%s\" for eid=%llu: "
		    "Unrecognized type=%u", name, eid, (unsigned int) type);
		return;
	}
	if ((n < 0) || (n >= sizeof (buf))) {
		zed_log_msg(LOG_WARNING,
		    "Failed to convert nvpair \"%s\" for eid=%llu: %s",
		    name, eid, "Exceeded buffer size");
		return;
	}
	if (zed_strings_add(zsp, buf) < 0) {
		zed_log_msg(LOG_WARNING,
		    "Failed to convert nvpair \"%s\" for eid=%llu: %s",
		    name, eid, strerror(ENOMEM));
		return;
	}
}

/*
 * Add the environment variable specified by the format string [fmt].
 */
static void
_zed_event_add_var(uint64_t eid, zed_strings_t *zsp, const char *fmt, ...)
{
	char buf[4096];
	va_list vargs;
	int n;
	const char *p;
	size_t namelen;

	assert(zsp != NULL);
	assert(fmt != NULL);

	va_start(vargs, fmt);
	n = vsnprintf(buf, sizeof (buf), fmt, vargs);
	va_end(vargs);
	p = strchr(buf, '=');
	namelen = (p) ? p - buf : strlen(buf);

	if ((n < 0) || (n >= sizeof (buf))) {
		zed_log_msg(LOG_WARNING, "Failed to add %.*s for eid=%llu: %s",
		    namelen, buf, eid, "Exceeded buffer size");
	} else if (!p) {
		zed_log_msg(LOG_WARNING, "Failed to add %.*s for eid=%llu: %s",
		    namelen, buf, eid, "Missing assignment");
	} else if (zed_strings_add(zsp, buf) < 0) {
		zed_log_msg(LOG_WARNING, "Failed to add %.*s for eid=%llu: %s",
		    namelen, buf, eid, strerror(ENOMEM));
	}
}

/*
 * Restrict various environment variables to safe and sane values
 * when constructing the environment for the child process.
 *
 * Reference: Secure Programming Cookbook by Viega & Messier, Section 1.1.
 */
static void
_zed_event_add_env_restrict(uint64_t eid, zed_strings_t *zsp)
{
	const char *env_restrict[] = {
		"IFS= \t\n",
		"PATH=" _PATH_STDPATH,
		"ZDB=" SBINDIR "/zdb",
		"ZED=" SBINDIR "/zed",
		"ZFS=" SBINDIR "/zfs",
		"ZINJECT=" SBINDIR "/zinject",
		"ZPOOL=" SBINDIR "/zpool",
		"ZFS_ALIAS=" ZFS_META_ALIAS,
		"ZFS_VERSION=" ZFS_META_VERSION,
		"ZFS_RELEASE=" ZFS_META_RELEASE,
		NULL
	};
	const char **pp;

	assert(zsp != NULL);

	for (pp = env_restrict; *pp; pp++) {
		_zed_event_add_var(eid, zsp, "%s", *pp);
	}
}

/*
 * Preserve specified variables from the parent environment
 * when constructing the environment for the child process.
 *
 * Reference: Secure Programming Cookbook by Viega & Messier, Section 1.1.
 */
static void
_zed_event_add_env_preserve(uint64_t eid, zed_strings_t *zsp)
{
	const char *env_preserve[] = {
		"TZ",
		NULL
	};
	const char **pp;
	const char *p;

	assert(zsp != NULL);

	for (pp = env_preserve; *pp; pp++) {
		if ((p = getenv(*pp)))
			_zed_event_add_var(eid, zsp, "%s=%s", *pp, p);
	}
}

/*
 * Compute the "subclass" by removing the first 3 components of [class]
 * (which seem to always be either "ereport.fs.zfs" or "resource.fs.zfs").
 * Return a pointer inside the string [class], or NULL if insufficient
 * components exist.
 */
static const char *
_zed_event_get_subclass(const char *class)
{
	const char *p;
	int i;

	if (!class)
		return (NULL);

	p = class;
	for (i = 0; i < 3; i++) {
		p = strchr(p, '.');
		if (!p)
			break;
		p++;
	}
	return (p);
}

/*
 * Convert the zevent time from a 2-element array of 64b integers
 * into a more convenient form:
 * - TIME_SECS is the second component of the time.
 * - TIME_NSECS is the nanosecond component of the time.
 * - TIME_STRING is an almost-RFC3339-compliant string representation.
 */
static void
_zed_event_add_time_strings(uint64_t eid, zed_strings_t *zsp, int64_t etime[])
{
	struct tm *stp;
	char buf[32];

	assert(zsp != NULL);
	assert(etime != NULL);

	_zed_event_add_var(eid, zsp, "%s%s=%lld",
	    ZEVENT_VAR_PREFIX, "TIME_SECS", (long long int) etime[0]);
	_zed_event_add_var(eid, zsp, "%s%s=%lld",
	    ZEVENT_VAR_PREFIX, "TIME_NSECS", (long long int) etime[1]);

	if (!(stp = localtime((const time_t *) &etime[0]))) {
		zed_log_msg(LOG_WARNING, "Failed to add %s%s for eid=%llu: %s",
		    ZEVENT_VAR_PREFIX, "TIME_STRING", eid, "localtime error");
	} else if (!strftime(buf, sizeof (buf), "%Y-%m-%d %H:%M:%S%z", stp)) {
		zed_log_msg(LOG_WARNING, "Failed to add %s%s for eid=%llu: %s",
		    ZEVENT_VAR_PREFIX, "TIME_STRING", eid, "strftime error");
	} else {
		_zed_event_add_var(eid, zsp, "%s%s=%s",
		    ZEVENT_VAR_PREFIX, "TIME_STRING", buf);
	}
}

/*
 * Service the next zevent, blocking until one is available.
 */
void
zed_event_service(struct zed_conf *zcp)
{
	nvlist_t *nvl;
	nvpair_t *nvp;
	int n_dropped;
	zed_strings_t *zsp;
	uint64_t eid;
	int64_t *etime;
	uint_t nelem;
	char *class;
	const char *subclass;
	int rv;

	if (!zcp) {
		errno = EINVAL;
		zed_log_msg(LOG_ERR, "Failed to service zevent: %s",
		    strerror(errno));
		return;
	}
	rv = zpool_events_next(zcp->zfs_hdl, &nvl, &n_dropped, ZEVENT_NONE,
	    zcp->zevent_fd);

	if ((rv != 0) || !nvl)
		return;

	if (n_dropped > 0) {
		zed_log_msg(LOG_WARNING, "Missed %d events", n_dropped);
		/*
		 * FIXME: Increase max size of event nvlist in
		 * /sys/module/zfs/parameters/zfs_zevent_len_max ?
		 */
	}
	if (nvlist_lookup_uint64(nvl, "eid", &eid) != 0) {
		zed_log_msg(LOG_WARNING, "Failed to lookup zevent eid");
	} else if (nvlist_lookup_int64_array(
	    nvl, "time", &etime, &nelem) != 0) {
		zed_log_msg(LOG_WARNING,
		    "Failed to lookup zevent time (eid=%llu)", eid);
	} else if (nelem != 2) {
		zed_log_msg(LOG_WARNING,
		    "Failed to lookup zevent time (eid=%llu, nelem=%u)",
		    eid, nelem);
	} else if (nvlist_lookup_string(nvl, "class", &class) != 0) {
		zed_log_msg(LOG_WARNING,
		    "Failed to lookup zevent class (eid=%llu)", eid);
	} else {
		zsp = zed_strings_create();

		nvp = NULL;
		while ((nvp = nvlist_next_nvpair(nvl, nvp)))
			_zed_event_add_nvpair(eid, zsp, nvp);

		_zed_event_add_env_restrict(eid, zsp);
		_zed_event_add_env_preserve(eid, zsp);

		_zed_event_add_var(eid, zsp, "%s%s=%d",
		    ZED_VAR_PREFIX, "PID", (int) getpid());
		_zed_event_add_var(eid, zsp, "%s%s=%s",
		    ZED_VAR_PREFIX, "SCRIPT_DIR", zcp->script_dir);

		subclass = _zed_event_get_subclass(class);
		_zed_event_add_var(eid, zsp, "%s%s=%s",
		    ZEVENT_VAR_PREFIX, "SUBCLASS",
		    (subclass ? subclass : class));
		_zed_event_add_time_strings(eid, zsp, etime);

		zed_exec_process(eid, class, subclass,
		    zcp->script_dir, zcp->scripts, zsp, zcp->zevent_fd);

		zed_conf_write_state(zcp, eid, etime);

		zed_strings_destroy(zsp);
	}
	nvlist_free(nvl);
}