1 /*-
2 * Copyright (c) 2003 Poul-Henning Kamp
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The names of the authors may not be used to endorse or promote
14 * products derived from this software without specific prior written
15 * permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD: stable/10/lib/libgeom/geom_stats.c 319303 2017-05-31 08:40:46Z ngie $
30 */
31
32 #include <sys/types.h>
33 #include <sys/devicestat.h>
34 #include <sys/mman.h>
35 #include <sys/time.h>
36 #include <errno.h>
37 #include <fcntl.h>
38 #include <paths.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <unistd.h>
42 #include <libgeom.h>
43
44 /************************************************************/
45 static uint npages, spp;
46 static int pagesize, statsfd = -1;
47 static u_char *statp;
48
49 void
geom_stats_close(void)50 geom_stats_close(void)
51 {
52 if (statsfd == -1)
53 return;
54 munmap(statp, npages *pagesize);
55 statp = NULL;
56 close (statsfd);
57 statsfd = -1;
58 }
59
60 void
geom_stats_resync(void)61 geom_stats_resync(void)
62 {
63 void *p;
64
65 if (statsfd == -1)
66 return;
67 for (;;) {
68 p = mmap(statp, (npages + 1) * pagesize,
69 PROT_READ, MAP_SHARED, statsfd, 0);
70 if (p == MAP_FAILED)
71 break;
72 else
73 statp = p;
74 npages++;
75 }
76 }
77
78 int
geom_stats_open(void)79 geom_stats_open(void)
80 {
81 int error;
82 void *p;
83
84 if (statsfd != -1)
85 return (EBUSY);
86 statsfd = open(_PATH_DEV DEVSTAT_DEVICE_NAME, O_RDONLY);
87 if (statsfd < 0)
88 return (errno);
89 pagesize = getpagesize();
90 spp = pagesize / sizeof(struct devstat);
91 p = mmap(NULL, pagesize, PROT_READ, MAP_SHARED, statsfd, 0);
92 if (p == MAP_FAILED) {
93 error = errno;
94 close(statsfd);
95 statsfd = -1;
96 errno = error;
97 return (error);
98 }
99 statp = p;
100 npages = 1;
101 geom_stats_resync();
102 return (0);
103 }
104
105 struct snapshot {
106 u_char *ptr;
107 uint pages;
108 uint pagesize;
109 uint perpage;
110 struct timespec time;
111 /* used by getnext: */
112 uint u, v;
113 };
114
115 void *
geom_stats_snapshot_get(void)116 geom_stats_snapshot_get(void)
117 {
118 struct snapshot *sp;
119
120 sp = malloc(sizeof *sp);
121 if (sp == NULL)
122 return (NULL);
123 memset(sp, 0, sizeof *sp);
124 sp->ptr = malloc(pagesize * npages);
125 if (sp->ptr == NULL) {
126 free(sp);
127 return (NULL);
128 }
129 memset(sp->ptr, 0, pagesize * npages); /* page in, cache */
130 clock_gettime(CLOCK_REALTIME, &sp->time);
131 memset(sp->ptr, 0, pagesize * npages); /* page in, cache */
132 memcpy(sp->ptr, statp, pagesize * npages);
133 sp->pages = npages;
134 sp->perpage = spp;
135 sp->pagesize = pagesize;
136 return (sp);
137 }
138
139 void
geom_stats_snapshot_free(void * arg)140 geom_stats_snapshot_free(void *arg)
141 {
142 struct snapshot *sp;
143
144 sp = arg;
145 free(sp->ptr);
146 free(sp);
147 }
148
149 void
geom_stats_snapshot_timestamp(void * arg,struct timespec * tp)150 geom_stats_snapshot_timestamp(void *arg, struct timespec *tp)
151 {
152 struct snapshot *sp;
153
154 sp = arg;
155 *tp = sp->time;
156 }
157
158 void
geom_stats_snapshot_reset(void * arg)159 geom_stats_snapshot_reset(void *arg)
160 {
161 struct snapshot *sp;
162
163 sp = arg;
164 sp->u = sp->v = 0;
165 }
166
167 struct devstat *
geom_stats_snapshot_next(void * arg)168 geom_stats_snapshot_next(void *arg)
169 {
170 struct devstat *gsp;
171 struct snapshot *sp;
172
173 sp = arg;
174 gsp = (struct devstat *)
175 (sp->ptr + sp->u * pagesize + sp->v * sizeof *gsp);
176 if (++sp->v >= sp->perpage) {
177 if (++sp->u >= sp->pages)
178 return (NULL);
179 else
180 sp->v = 0;
181 }
182 return (gsp);
183 }
184