1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2003 Poul-Henning Kamp
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. The names of the authors may not be used to endorse or promote
16 *    products derived from this software without specific prior written
17 *    permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/types.h>
33#include <sys/ioctl.h>
34#include <sys/disk.h>
35#include <sys/devicestat.h>
36#include <sys/mman.h>
37#include <sys/time.h>
38#include <err.h>
39#include <errno.h>
40#include <fcntl.h>
41#include <paths.h>
42#include <stdlib.h>
43#include <string.h>
44#include <unistd.h>
45#include <libgeom.h>
46
47/************************************************************/
48static uint npages, spp;
49static int pagesize, statsfd = -1;
50static u_char *statp;
51
52void
53geom_stats_close(void)
54{
55	if (statsfd == -1)
56		return;
57	munmap(statp, npages * pagesize);
58	statp = NULL;
59	close (statsfd);
60	statsfd = -1;
61}
62
63void
64geom_stats_resync(void)
65{
66	void *p;
67	off_t mediasize;
68	int error;
69
70	if (statsfd == -1)
71		return;
72	error = ioctl(statsfd, DIOCGMEDIASIZE, &mediasize);
73	if (error)
74		err(1, "DIOCGMEDIASIZE(" _PATH_DEV DEVSTAT_DEVICE_NAME ")");
75
76	munmap(statp, npages * pagesize);
77	p = mmap(statp, mediasize, PROT_READ, MAP_SHARED, statsfd, 0);
78	if (p == MAP_FAILED)
79		err(1, "mmap(/dev/devstat):");
80	else {
81		statp = p;
82		npages = mediasize / pagesize;
83	}
84}
85
86int
87geom_stats_open(void)
88{
89	int error;
90	void *p;
91
92	if (statsfd != -1)
93		return (EBUSY);
94	statsfd = open(_PATH_DEV DEVSTAT_DEVICE_NAME, O_RDONLY);
95	if (statsfd < 0)
96		return (errno);
97	pagesize = getpagesize();
98	spp = pagesize / sizeof(struct devstat);
99	p = mmap(NULL, pagesize, PROT_READ, MAP_SHARED, statsfd, 0);
100	if (p == MAP_FAILED) {
101		error = errno;
102		close(statsfd);
103		statsfd = -1;
104		errno = error;
105		return (error);
106	}
107	statp = p;
108	npages = 1;
109	geom_stats_resync();
110	return (0);
111}
112
113struct snapshot {
114	u_char		*ptr;
115	uint		pages;
116	uint		pagesize;
117	uint		perpage;
118	struct timespec	time;
119	/* used by getnext: */
120	uint		u, v;
121};
122
123void *
124geom_stats_snapshot_get(void)
125{
126	struct snapshot *sp;
127
128	sp = malloc(sizeof *sp);
129	if (sp == NULL)
130		return (NULL);
131	memset(sp, 0, sizeof *sp);
132	sp->ptr = malloc(pagesize * npages);
133	if (sp->ptr == NULL) {
134		free(sp);
135		return (NULL);
136	}
137	explicit_bzero(sp->ptr, pagesize * npages); 	/* page in, cache */
138	clock_gettime(CLOCK_REALTIME, &sp->time);
139	memcpy(sp->ptr, statp, pagesize * npages);
140	sp->pages = npages;
141	sp->perpage = spp;
142	sp->pagesize = pagesize;
143	return (sp);
144}
145
146void
147geom_stats_snapshot_free(void *arg)
148{
149	struct snapshot *sp;
150
151	sp = arg;
152	free(sp->ptr);
153	free(sp);
154}
155
156void
157geom_stats_snapshot_timestamp(void *arg, struct timespec *tp)
158{
159	struct snapshot *sp;
160
161	sp = arg;
162	*tp = sp->time;
163}
164
165void
166geom_stats_snapshot_reset(void *arg)
167{
168	struct snapshot *sp;
169
170	sp = arg;
171	sp->u = sp->v = 0;
172}
173
174struct devstat *
175geom_stats_snapshot_next(void *arg)
176{
177	struct devstat *gsp;
178	struct snapshot *sp;
179
180	sp = arg;
181	gsp = (struct devstat *)
182	    (sp->ptr + sp->u * pagesize + sp->v * sizeof *gsp);
183	if (++sp->v >= sp->perpage) {
184		if (++sp->u >= sp->pages)
185			return (NULL);
186		else
187			sp->v = 0;
188	}
189	return (gsp);
190}
191