1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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 * $FreeBSD$
32 */
33
34#include <sys/types.h>
35#include <sys/ioctl.h>
36#include <sys/disk.h>
37#include <sys/devicestat.h>
38#include <sys/mman.h>
39#include <sys/time.h>
40#include <err.h>
41#include <errno.h>
42#include <fcntl.h>
43#include <paths.h>
44#include <stdlib.h>
45#include <string.h>
46#include <unistd.h>
47#include <libgeom.h>
48
49/************************************************************/
50static uint npages, spp;
51static int pagesize, statsfd = -1;
52static u_char *statp;
53
54void
55geom_stats_close(void)
56{
57	if (statsfd == -1)
58		return;
59	munmap(statp, npages * pagesize);
60	statp = NULL;
61	close (statsfd);
62	statsfd = -1;
63}
64
65void
66geom_stats_resync(void)
67{
68	void *p;
69	off_t mediasize;
70	int error;
71
72	if (statsfd == -1)
73		return;
74	error = ioctl(statsfd, DIOCGMEDIASIZE, &mediasize);
75	if (error)
76		err(1, "DIOCGMEDIASIZE(" _PATH_DEV DEVSTAT_DEVICE_NAME ")");
77
78	munmap(statp, npages * pagesize);
79	p = mmap(statp, mediasize, PROT_READ, MAP_SHARED, statsfd, 0);
80	if (p == MAP_FAILED)
81		err(1, "mmap(/dev/devstat):");
82	else {
83		statp = p;
84		npages = mediasize / pagesize;
85	}
86}
87
88int
89geom_stats_open(void)
90{
91	int error;
92	void *p;
93
94	if (statsfd != -1)
95		return (EBUSY);
96	statsfd = open(_PATH_DEV DEVSTAT_DEVICE_NAME, O_RDONLY);
97	if (statsfd < 0)
98		return (errno);
99	pagesize = getpagesize();
100	spp = pagesize / sizeof(struct devstat);
101	p = mmap(NULL, pagesize, PROT_READ, MAP_SHARED, statsfd, 0);
102	if (p == MAP_FAILED) {
103		error = errno;
104		close(statsfd);
105		statsfd = -1;
106		errno = error;
107		return (error);
108	}
109	statp = p;
110	npages = 1;
111	geom_stats_resync();
112	return (0);
113}
114
115struct snapshot {
116	u_char		*ptr;
117	uint		pages;
118	uint		pagesize;
119	uint		perpage;
120	struct timespec	time;
121	/* used by getnext: */
122	uint		u, v;
123};
124
125void *
126geom_stats_snapshot_get(void)
127{
128	struct snapshot *sp;
129
130	sp = malloc(sizeof *sp);
131	if (sp == NULL)
132		return (NULL);
133	memset(sp, 0, sizeof *sp);
134	sp->ptr = malloc(pagesize * npages);
135	if (sp->ptr == NULL) {
136		free(sp);
137		return (NULL);
138	}
139	explicit_bzero(sp->ptr, pagesize * npages); 	/* page in, cache */
140	clock_gettime(CLOCK_REALTIME, &sp->time);
141	memcpy(sp->ptr, statp, pagesize * npages);
142	sp->pages = npages;
143	sp->perpage = spp;
144	sp->pagesize = pagesize;
145	return (sp);
146}
147
148void
149geom_stats_snapshot_free(void *arg)
150{
151	struct snapshot *sp;
152
153	sp = arg;
154	free(sp->ptr);
155	free(sp);
156}
157
158void
159geom_stats_snapshot_timestamp(void *arg, struct timespec *tp)
160{
161	struct snapshot *sp;
162
163	sp = arg;
164	*tp = sp->time;
165}
166
167void
168geom_stats_snapshot_reset(void *arg)
169{
170	struct snapshot *sp;
171
172	sp = arg;
173	sp->u = sp->v = 0;
174}
175
176struct devstat *
177geom_stats_snapshot_next(void *arg)
178{
179	struct devstat *gsp;
180	struct snapshot *sp;
181
182	sp = arg;
183	gsp = (struct devstat *)
184	    (sp->ptr + sp->u * pagesize + sp->v * sizeof *gsp);
185	if (++sp->v >= sp->perpage) {
186		if (++sp->u >= sp->pages)
187			return (NULL);
188		else
189			sp->v = 0;
190	}
191	return (gsp);
192}
193