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 * $FreeBSD$ 30 */ 31 32 #include <paths.h> 33 #include <errno.h> 34 #include <fcntl.h> 35 #include <stdlib.h> 36 #include <string.h> 37 #include <unistd.h> 38 #include <libgeom.h> 39 40 #include <sys/mman.h> 41 #include <sys/time.h> 42 #include <sys/types.h> 43 #include <sys/devicestat.h> 44 45 46 /************************************************************/ 47 static uint npages, pagesize, spp; 48 static int statsfd = -1; 49 static u_char *statp; 50 51 void 52 geom_stats_close(void) 53 { 54 if (statsfd == -1) 55 return; 56 munmap(statp, npages *pagesize); 57 statp = NULL; 58 close (statsfd); 59 statsfd = -1; 60 } 61 62 void 63 geom_stats_resync(void) 64 { 65 void *p; 66 67 if (statsfd == -1) 68 return; 69 for (;;) { 70 p = mmap(statp, (npages + 1) * pagesize, 71 PROT_READ, MAP_SHARED, statsfd, 0); 72 if (p == MAP_FAILED) 73 break; 74 else 75 statp = p; 76 npages++; 77 } 78 } 79 80 int 81 geom_stats_open(void) 82 { 83 int error; 84 void *p; 85 86 if (statsfd != -1) 87 return (EBUSY); 88 statsfd = open(_PATH_DEV DEVSTAT_DEVICE_NAME, O_RDONLY); 89 if (statsfd < 0) 90 return (errno); 91 pagesize = getpagesize(); 92 spp = pagesize / sizeof(struct devstat); 93 p = mmap(NULL, pagesize, PROT_READ, MAP_SHARED, statsfd, 0); 94 if (p == MAP_FAILED) { 95 error = errno; 96 close(statsfd); 97 statsfd = -1; 98 errno = error; 99 return (error); 100 } 101 statp = p; 102 npages = 1; 103 geom_stats_resync(); 104 return (0); 105 } 106 107 struct snapshot { 108 u_char *ptr; 109 uint pages; 110 uint pagesize; 111 uint perpage; 112 struct timespec time; 113 /* used by getnext: */ 114 uint u, v; 115 }; 116 117 void * 118 geom_stats_snapshot_get(void) 119 { 120 struct snapshot *sp; 121 122 sp = malloc(sizeof *sp); 123 if (sp == NULL) 124 return (NULL); 125 memset(sp, 0, sizeof *sp); 126 sp->ptr = malloc(pagesize * npages); 127 if (sp->ptr == NULL) { 128 free(sp); 129 return (NULL); 130 } 131 memset(sp->ptr, 0, pagesize * npages); /* page in, cache */ 132 clock_gettime(CLOCK_REALTIME, &sp->time); 133 memset(sp->ptr, 0, pagesize * npages); /* page in, cache */ 134 memcpy(sp->ptr, statp, pagesize * npages); 135 sp->pages = npages; 136 sp->perpage = spp; 137 sp->pagesize = pagesize; 138 return (sp); 139 } 140 141 void 142 geom_stats_snapshot_free(void *arg) 143 { 144 struct snapshot *sp; 145 146 sp = arg; 147 free(sp->ptr); 148 free(sp); 149 } 150 151 void 152 geom_stats_snapshot_timestamp(void *arg, struct timespec *tp) 153 { 154 struct snapshot *sp; 155 156 sp = arg; 157 *tp = sp->time; 158 } 159 160 void 161 geom_stats_snapshot_reset(void *arg) 162 { 163 struct snapshot *sp; 164 165 sp = arg; 166 sp->u = sp->v = 0; 167 } 168 169 struct devstat * 170 geom_stats_snapshot_next(void *arg) 171 { 172 struct devstat *gsp; 173 struct snapshot *sp; 174 175 sp = arg; 176 gsp = (struct devstat *) 177 (sp->ptr + sp->u * pagesize + sp->v * sizeof *gsp); 178 if (++sp->v >= sp->perpage) { 179 if (++sp->u >= sp->pages) 180 return (NULL); 181 else 182 sp->v = 0; 183 } 184 return (gsp); 185 } 186