1 /*-
2 * SPDX-License-Identifier: BSD-3-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: stable/12/lib/libgeom/geom_stats.c 370203 2021-07-27 17:42:04Z asomers $
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 /************************************************************/
50 static uint npages, spp;
51 static int pagesize, statsfd = -1;
52 static u_char *statp;
53
54 void
geom_stats_close(void)55 geom_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
65 void
geom_stats_resync(void)66 geom_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
88 int
geom_stats_open(void)89 geom_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
115 struct 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
125 void *
geom_stats_snapshot_get(void)126 geom_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
148 void
geom_stats_snapshot_free(void * arg)149 geom_stats_snapshot_free(void *arg)
150 {
151 struct snapshot *sp;
152
153 sp = arg;
154 free(sp->ptr);
155 free(sp);
156 }
157
158 void
geom_stats_snapshot_timestamp(void * arg,struct timespec * tp)159 geom_stats_snapshot_timestamp(void *arg, struct timespec *tp)
160 {
161 struct snapshot *sp;
162
163 sp = arg;
164 *tp = sp->time;
165 }
166
167 void
geom_stats_snapshot_reset(void * arg)168 geom_stats_snapshot_reset(void *arg)
169 {
170 struct snapshot *sp;
171
172 sp = arg;
173 sp->u = sp->v = 0;
174 }
175
176 struct devstat *
geom_stats_snapshot_next(void * arg)177 geom_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