1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22/*
23 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 *
26 * Copyright (c) 2016, Intel Corporation.
27 */
28
29#include <assert.h>
30#include <stddef.h>
31#include <stdlib.h>
32#include <strings.h>
33#include <sys/list.h>
34#include <sys/time.h>
35
36#include "fmd_api.h"
37#include "fmd_serd.h"
38#include "../zed_log.h"
39
40
41#define	FMD_STR_BUCKETS		211
42
43
44#ifdef SERD_ENG_DEBUG
45#define	serd_log_msg(fmt, ...) \
46	zed_log_msg(LOG_INFO, fmt, __VA_ARGS__)
47#else
48#define	serd_log_msg(fmt, ...)
49#endif
50
51
52/*
53 * SERD Engine Backend
54 */
55
56/*
57 * Compute the delta between events in nanoseconds.  To account for very old
58 * events which are replayed, we must handle the case where time is negative.
59 * We convert the hrtime_t's to unsigned 64-bit integers and then handle the
60 * case where 'old' is greater than 'new' (i.e. high-res time has wrapped).
61 */
62static hrtime_t
63fmd_event_delta(hrtime_t t1, hrtime_t t2)
64{
65	uint64_t old = t1;
66	uint64_t new = t2;
67
68	return (new >= old ? new - old : (UINT64_MAX - old) + new + 1);
69}
70
71static fmd_serd_eng_t *
72fmd_serd_eng_alloc(const char *name, uint64_t n, hrtime_t t)
73{
74	fmd_serd_eng_t *sgp;
75
76	sgp = malloc(sizeof (fmd_serd_eng_t));
77	bzero(sgp, sizeof (fmd_serd_eng_t));
78
79	sgp->sg_name = strdup(name);
80	sgp->sg_flags = FMD_SERD_DIRTY;
81	sgp->sg_n = n;
82	sgp->sg_t = t;
83
84	list_create(&sgp->sg_list, sizeof (fmd_serd_elem_t),
85	    offsetof(fmd_serd_elem_t, se_list));
86
87	return (sgp);
88}
89
90static void
91fmd_serd_eng_free(fmd_serd_eng_t *sgp)
92{
93	fmd_serd_eng_reset(sgp);
94	free(sgp->sg_name);
95	list_destroy(&sgp->sg_list);
96	free(sgp);
97}
98
99/*
100 * sourced from fmd_string.c
101 */
102static ulong_t
103fmd_strhash(const char *key)
104{
105	ulong_t g, h = 0;
106	const char *p;
107
108	for (p = key; *p != '\0'; p++) {
109		h = (h << 4) + *p;
110
111		if ((g = (h & 0xf0000000)) != 0) {
112			h ^= (g >> 24);
113			h ^= g;
114		}
115	}
116
117	return (h);
118}
119
120void
121fmd_serd_hash_create(fmd_serd_hash_t *shp)
122{
123	shp->sh_hashlen = FMD_STR_BUCKETS;
124	shp->sh_hash = calloc(shp->sh_hashlen, sizeof (void *));
125	shp->sh_count = 0;
126}
127
128void
129fmd_serd_hash_destroy(fmd_serd_hash_t *shp)
130{
131	fmd_serd_eng_t *sgp, *ngp;
132	uint_t i;
133
134	for (i = 0; i < shp->sh_hashlen; i++) {
135		for (sgp = shp->sh_hash[i]; sgp != NULL; sgp = ngp) {
136			ngp = sgp->sg_next;
137			fmd_serd_eng_free(sgp);
138		}
139	}
140
141	free(shp->sh_hash);
142	bzero(shp, sizeof (fmd_serd_hash_t));
143}
144
145void
146fmd_serd_hash_apply(fmd_serd_hash_t *shp, fmd_serd_eng_f *func, void *arg)
147{
148	fmd_serd_eng_t *sgp;
149	uint_t i;
150
151	for (i = 0; i < shp->sh_hashlen; i++) {
152		for (sgp = shp->sh_hash[i]; sgp != NULL; sgp = sgp->sg_next)
153			func(sgp, arg);
154	}
155}
156
157fmd_serd_eng_t *
158fmd_serd_eng_insert(fmd_serd_hash_t *shp, const char *name,
159    uint_t n, hrtime_t t)
160{
161	uint_t h = fmd_strhash(name) % shp->sh_hashlen;
162	fmd_serd_eng_t *sgp = fmd_serd_eng_alloc(name, n, t);
163
164	serd_log_msg("  SERD Engine: inserting  %s N %d T %llu",
165	    name, (int)n, (long long unsigned)t);
166
167	sgp->sg_next = shp->sh_hash[h];
168	shp->sh_hash[h] = sgp;
169	shp->sh_count++;
170
171	return (sgp);
172}
173
174fmd_serd_eng_t *
175fmd_serd_eng_lookup(fmd_serd_hash_t *shp, const char *name)
176{
177	uint_t h = fmd_strhash(name) % shp->sh_hashlen;
178	fmd_serd_eng_t *sgp;
179
180	for (sgp = shp->sh_hash[h]; sgp != NULL; sgp = sgp->sg_next) {
181		if (strcmp(name, sgp->sg_name) == 0)
182			return (sgp);
183	}
184
185	return (NULL);
186}
187
188void
189fmd_serd_eng_delete(fmd_serd_hash_t *shp, const char *name)
190{
191	uint_t h = fmd_strhash(name) % shp->sh_hashlen;
192	fmd_serd_eng_t *sgp, **pp = &shp->sh_hash[h];
193
194	serd_log_msg("  SERD Engine: deleting %s", name);
195
196	for (sgp = *pp; sgp != NULL; sgp = sgp->sg_next) {
197		if (strcmp(sgp->sg_name, name) != 0)
198			pp = &sgp->sg_next;
199		else
200			break;
201	}
202
203	if (sgp != NULL) {
204		*pp = sgp->sg_next;
205		fmd_serd_eng_free(sgp);
206		assert(shp->sh_count != 0);
207		shp->sh_count--;
208	}
209}
210
211static void
212fmd_serd_eng_discard(fmd_serd_eng_t *sgp, fmd_serd_elem_t *sep)
213{
214	list_remove(&sgp->sg_list, sep);
215	sgp->sg_count--;
216
217	serd_log_msg("  SERD Engine: discarding %s, %d remaining",
218	    sgp->sg_name, (int)sgp->sg_count);
219
220	free(sep);
221}
222
223int
224fmd_serd_eng_record(fmd_serd_eng_t *sgp, hrtime_t hrt)
225{
226	fmd_serd_elem_t *sep, *oep;
227
228	/*
229	 * If the fired flag is already set, return false and discard the
230	 * event.  This means that the caller will only see the engine "fire"
231	 * once until fmd_serd_eng_reset() is called.  The fmd_serd_eng_fired()
232	 * function can also be used in combination with fmd_serd_eng_record().
233	 */
234	if (sgp->sg_flags & FMD_SERD_FIRED) {
235		serd_log_msg("  SERD Engine: record %s already fired!",
236		    sgp->sg_name);
237		return (FMD_B_FALSE);
238	}
239
240	while (sgp->sg_count >= sgp->sg_n)
241		fmd_serd_eng_discard(sgp, list_tail(&sgp->sg_list));
242
243	sep = malloc(sizeof (fmd_serd_elem_t));
244	sep->se_hrt = hrt;
245
246	list_insert_head(&sgp->sg_list, sep);
247	sgp->sg_count++;
248
249	serd_log_msg("  SERD Engine: recording %s of %d (%llu)",
250	    sgp->sg_name, (int)sgp->sg_count, (long long unsigned)hrt);
251
252	/*
253	 * Pick up the oldest element pointer for comparison to 'sep'.  We must
254	 * do this after adding 'sep' because 'oep' and 'sep' can be the same.
255	 */
256	oep = list_tail(&sgp->sg_list);
257
258	if (sgp->sg_count >= sgp->sg_n &&
259	    fmd_event_delta(oep->se_hrt, sep->se_hrt) <= sgp->sg_t) {
260		sgp->sg_flags |= FMD_SERD_FIRED | FMD_SERD_DIRTY;
261		serd_log_msg("  SERD Engine: fired %s", sgp->sg_name);
262		return (FMD_B_TRUE);
263	}
264
265	sgp->sg_flags |= FMD_SERD_DIRTY;
266	return (FMD_B_FALSE);
267}
268
269int
270fmd_serd_eng_fired(fmd_serd_eng_t *sgp)
271{
272	return (sgp->sg_flags & FMD_SERD_FIRED);
273}
274
275int
276fmd_serd_eng_empty(fmd_serd_eng_t *sgp)
277{
278	return (sgp->sg_count == 0);
279}
280
281void
282fmd_serd_eng_reset(fmd_serd_eng_t *sgp)
283{
284	serd_log_msg("  SERD Engine: resetting %s", sgp->sg_name);
285
286	while (sgp->sg_count != 0)
287		fmd_serd_eng_discard(sgp, list_head(&sgp->sg_list));
288
289	sgp->sg_flags &= ~FMD_SERD_FIRED;
290	sgp->sg_flags |= FMD_SERD_DIRTY;
291}
292
293void
294fmd_serd_eng_gc(fmd_serd_eng_t *sgp)
295{
296	fmd_serd_elem_t *sep, *nep;
297	hrtime_t hrt;
298
299	if (sgp->sg_count == 0 || (sgp->sg_flags & FMD_SERD_FIRED))
300		return; /* no garbage collection needed if empty or fired */
301
302	sep = list_head(&sgp->sg_list);
303	if (sep == NULL)
304		return;
305
306	hrt = sep->se_hrt - sgp->sg_t;
307
308	for (sep = list_head(&sgp->sg_list); sep != NULL; sep = nep) {
309		if (sep->se_hrt >= hrt)
310			break; /* sep and subsequent events are all within T */
311
312		nep = list_next(&sgp->sg_list, sep);
313		fmd_serd_eng_discard(sgp, sep);
314		sgp->sg_flags |= FMD_SERD_DIRTY;
315	}
316}
317