| 1 | /* $NetBSD: sysmon.c,v 1.28 2015/05/05 09:22:33 pgoyette Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 2000 Zembu Labs, Inc. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * Author: Jason R. Thorpe <thorpej@zembu.com> |
| 8 | * |
| 9 | * Redistribution and use in source and binary forms, with or without |
| 10 | * modification, are permitted provided that the following conditions |
| 11 | * are met: |
| 12 | * 1. Redistributions of source code must retain the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer. |
| 14 | * 2. Redistributions in binary form must reproduce the above copyright |
| 15 | * notice, this list of conditions and the following disclaimer in the |
| 16 | * documentation and/or other materials provided with the distribution. |
| 17 | * 3. All advertising materials mentioning features or use of this software |
| 18 | * must display the following acknowledgement: |
| 19 | * This product includes software developed by Zembu Labs, Inc. |
| 20 | * 4. Neither the name of Zembu Labs nor the names of its employees may |
| 21 | * be used to endorse or promote products derived from this software |
| 22 | * without specific prior written permission. |
| 23 | * |
| 24 | * THIS SOFTWARE IS PROVIDED BY ZEMBU LABS, INC. ``AS IS'' AND ANY EXPRESS |
| 25 | * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WAR- |
| 26 | * RANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DIS- |
| 27 | * CLAIMED. IN NO EVENT SHALL ZEMBU LABS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 28 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 29 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 30 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 31 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 32 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 33 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 34 | */ |
| 35 | |
| 36 | /* |
| 37 | * Clearing house for system monitoring hardware. We currently |
| 38 | * handle environmental sensors, watchdog timers, and power management. |
| 39 | */ |
| 40 | |
| 41 | #include <sys/cdefs.h> |
| 42 | __KERNEL_RCSID(0, "$NetBSD: sysmon.c,v 1.28 2015/05/05 09:22:33 pgoyette Exp $" ); |
| 43 | |
| 44 | #include <sys/param.h> |
| 45 | #include <sys/conf.h> |
| 46 | #include <sys/errno.h> |
| 47 | #include <sys/fcntl.h> |
| 48 | #include <sys/callout.h> |
| 49 | #include <sys/kernel.h> |
| 50 | #include <sys/systm.h> |
| 51 | #include <sys/proc.h> |
| 52 | #include <sys/module.h> |
| 53 | #include <sys/mutex.h> |
| 54 | #include <sys/device.h> |
| 55 | #include <sys/once.h> |
| 56 | |
| 57 | #include <dev/sysmon/sysmonvar.h> |
| 58 | |
| 59 | dev_type_open(sysmonopen); |
| 60 | dev_type_close(sysmonclose); |
| 61 | dev_type_ioctl(sysmonioctl); |
| 62 | dev_type_read(sysmonread); |
| 63 | dev_type_poll(sysmonpoll); |
| 64 | dev_type_kqfilter(sysmonkqfilter); |
| 65 | |
| 66 | const struct cdevsw sysmon_cdevsw = { |
| 67 | .d_open = sysmonopen, |
| 68 | .d_close = sysmonclose, |
| 69 | .d_read = sysmonread, |
| 70 | .d_write = nowrite, |
| 71 | .d_ioctl = sysmonioctl, |
| 72 | .d_stop = nostop, |
| 73 | .d_tty = notty, |
| 74 | .d_poll = sysmonpoll, |
| 75 | .d_mmap = nommap, |
| 76 | .d_kqfilter = sysmonkqfilter, |
| 77 | .d_discard = nodiscard, |
| 78 | .d_flag = D_OTHER | D_MPSAFE |
| 79 | }; |
| 80 | |
| 81 | static int sysmon_modcmd(modcmd_t, void *); |
| 82 | static int sm_init_once(void); |
| 83 | |
| 84 | /* |
| 85 | * Info about our minor "devices" |
| 86 | */ |
| 87 | static struct sysmon_opvec *sysmon_opvec_table[] = { NULL, NULL, NULL }; |
| 88 | static int sysmon_refcnt[] = { 0, 0, 0 }; |
| 89 | static const char *sysmon_mod[] = { "sysmon_envsys" , |
| 90 | "sysmon_wdog" , |
| 91 | "sysmon_power" }; |
| 92 | static kmutex_t sysmon_minor_mtx; |
| 93 | |
| 94 | #ifdef _MODULE |
| 95 | static bool sm_is_attached; |
| 96 | #endif |
| 97 | |
| 98 | ONCE_DECL(once_sm); |
| 99 | |
| 100 | /* |
| 101 | * sysmon_attach_minor |
| 102 | * |
| 103 | * Attach a minor device for wdog, power, or envsys. Manage a |
| 104 | * reference count so we can prevent the device from being |
| 105 | * detached if there are still users with the minor device opened. |
| 106 | * |
| 107 | * If the opvec argument is NULL, this is a request to detach the |
| 108 | * minor device - make sure the refcnt is zero! |
| 109 | */ |
| 110 | int |
| 111 | sysmon_attach_minor(int minor, struct sysmon_opvec *opvec) |
| 112 | { |
| 113 | int ret; |
| 114 | |
| 115 | mutex_enter(&sysmon_minor_mtx); |
| 116 | if (opvec) { |
| 117 | if (sysmon_opvec_table[minor] == NULL) { |
| 118 | sysmon_refcnt[minor] = 0; |
| 119 | sysmon_opvec_table[minor] = opvec; |
| 120 | ret = 0; |
| 121 | } else |
| 122 | ret = EEXIST; |
| 123 | } else { |
| 124 | if (sysmon_refcnt[minor] == 0) { |
| 125 | sysmon_opvec_table[minor] = NULL; |
| 126 | ret = 0; |
| 127 | } else |
| 128 | ret = EBUSY; |
| 129 | } |
| 130 | |
| 131 | mutex_exit(&sysmon_minor_mtx); |
| 132 | return ret; |
| 133 | } |
| 134 | |
| 135 | /* |
| 136 | * sysmonopen: |
| 137 | * |
| 138 | * Open the system monitor device. |
| 139 | */ |
| 140 | int |
| 141 | sysmonopen(dev_t dev, int flag, int mode, struct lwp *l) |
| 142 | { |
| 143 | int error; |
| 144 | |
| 145 | mutex_enter(&sysmon_minor_mtx); |
| 146 | |
| 147 | switch (minor(dev)) { |
| 148 | case SYSMON_MINOR_ENVSYS: |
| 149 | case SYSMON_MINOR_WDOG: |
| 150 | case SYSMON_MINOR_POWER: |
| 151 | if (sysmon_opvec_table[minor(dev)] == NULL) { |
| 152 | mutex_exit(&sysmon_minor_mtx); |
| 153 | error = module_autoload(sysmon_mod[minor(dev)], |
| 154 | MODULE_CLASS_MISC); |
| 155 | if (error) |
| 156 | return error; |
| 157 | mutex_enter(&sysmon_minor_mtx); |
| 158 | if (sysmon_opvec_table[minor(dev)] == NULL) { |
| 159 | error = ENODEV; |
| 160 | break; |
| 161 | } |
| 162 | } |
| 163 | error = (sysmon_opvec_table[minor(dev)]->so_open)(dev, flag, |
| 164 | mode, l); |
| 165 | if (error == 0) |
| 166 | sysmon_refcnt[minor(dev)]++; |
| 167 | break; |
| 168 | default: |
| 169 | error = ENODEV; |
| 170 | } |
| 171 | |
| 172 | mutex_exit(&sysmon_minor_mtx); |
| 173 | return error; |
| 174 | } |
| 175 | |
| 176 | /* |
| 177 | * sysmonclose: |
| 178 | * |
| 179 | * Close the system monitor device. |
| 180 | */ |
| 181 | int |
| 182 | sysmonclose(dev_t dev, int flag, int mode, struct lwp *l) |
| 183 | { |
| 184 | int error; |
| 185 | |
| 186 | switch (minor(dev)) { |
| 187 | case SYSMON_MINOR_ENVSYS: |
| 188 | case SYSMON_MINOR_WDOG: |
| 189 | case SYSMON_MINOR_POWER: |
| 190 | if (sysmon_opvec_table[minor(dev)] == NULL) |
| 191 | error = ENODEV; |
| 192 | else { |
| 193 | error = (sysmon_opvec_table[minor(dev)]->so_close)(dev, |
| 194 | flag, mode, l); |
| 195 | if (error == 0) { |
| 196 | sysmon_refcnt[minor(dev)]--; |
| 197 | KASSERT(sysmon_refcnt[minor(dev)] >= 0); |
| 198 | } |
| 199 | } |
| 200 | break; |
| 201 | default: |
| 202 | error = ENODEV; |
| 203 | } |
| 204 | |
| 205 | return (error); |
| 206 | } |
| 207 | |
| 208 | /* |
| 209 | * sysmonioctl: |
| 210 | * |
| 211 | * Perform a control request. |
| 212 | */ |
| 213 | int |
| 214 | sysmonioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l) |
| 215 | { |
| 216 | int error; |
| 217 | |
| 218 | switch (minor(dev)) { |
| 219 | case SYSMON_MINOR_ENVSYS: |
| 220 | case SYSMON_MINOR_WDOG: |
| 221 | case SYSMON_MINOR_POWER: |
| 222 | if (sysmon_opvec_table[minor(dev)] == NULL) |
| 223 | error = ENODEV; |
| 224 | else |
| 225 | error = (sysmon_opvec_table[minor(dev)]->so_ioctl)(dev, |
| 226 | cmd, data, flag, l); |
| 227 | break; |
| 228 | default: |
| 229 | error = ENODEV; |
| 230 | } |
| 231 | |
| 232 | return (error); |
| 233 | } |
| 234 | |
| 235 | /* |
| 236 | * sysmonread: |
| 237 | * |
| 238 | * Perform a read request. |
| 239 | */ |
| 240 | int |
| 241 | sysmonread(dev_t dev, struct uio *uio, int flags) |
| 242 | { |
| 243 | int error; |
| 244 | |
| 245 | switch (minor(dev)) { |
| 246 | case SYSMON_MINOR_POWER: |
| 247 | if (sysmon_opvec_table[minor(dev)] == NULL) |
| 248 | error = ENODEV; |
| 249 | else |
| 250 | error = (sysmon_opvec_table[minor(dev)]->so_read)(dev, |
| 251 | uio, flags); |
| 252 | break; |
| 253 | default: |
| 254 | error = ENODEV; |
| 255 | } |
| 256 | |
| 257 | return (error); |
| 258 | } |
| 259 | |
| 260 | /* |
| 261 | * sysmonpoll: |
| 262 | * |
| 263 | * Poll the system monitor device. |
| 264 | */ |
| 265 | int |
| 266 | sysmonpoll(dev_t dev, int events, struct lwp *l) |
| 267 | { |
| 268 | int rv; |
| 269 | |
| 270 | switch (minor(dev)) { |
| 271 | case SYSMON_MINOR_POWER: |
| 272 | if (sysmon_opvec_table[minor(dev)] == NULL) |
| 273 | rv = events; |
| 274 | else |
| 275 | rv = (sysmon_opvec_table[minor(dev)]->so_poll)(dev, |
| 276 | events, l); |
| 277 | break; |
| 278 | default: |
| 279 | rv = events; |
| 280 | } |
| 281 | |
| 282 | return (rv); |
| 283 | } |
| 284 | |
| 285 | /* |
| 286 | * sysmonkqfilter: |
| 287 | * |
| 288 | * Kqueue filter for the system monitor device. |
| 289 | */ |
| 290 | int |
| 291 | sysmonkqfilter(dev_t dev, struct knote *kn) |
| 292 | { |
| 293 | int error; |
| 294 | |
| 295 | switch (minor(dev)) { |
| 296 | case SYSMON_MINOR_POWER: |
| 297 | if (sysmon_opvec_table[minor(dev)] == NULL) |
| 298 | error = ENODEV; |
| 299 | else |
| 300 | error = (sysmon_opvec_table[minor(dev)]->so_filter)(dev, |
| 301 | kn); |
| 302 | break; |
| 303 | default: |
| 304 | error = 1; |
| 305 | } |
| 306 | |
| 307 | return (error); |
| 308 | } |
| 309 | |
| 310 | MODULE(MODULE_CLASS_DRIVER, sysmon, "" ); |
| 311 | |
| 312 | static int |
| 313 | sm_init_once(void) |
| 314 | { |
| 315 | |
| 316 | mutex_init(&sysmon_minor_mtx, MUTEX_DEFAULT, IPL_NONE); |
| 317 | |
| 318 | return 0; |
| 319 | } |
| 320 | |
| 321 | int |
| 322 | sysmon_init(void) |
| 323 | { |
| 324 | int error; |
| 325 | #ifdef _MODULE |
| 326 | devmajor_t bmajor, cmajor; |
| 327 | #endif |
| 328 | |
| 329 | error = RUN_ONCE(&once_sm, sm_init_once); |
| 330 | |
| 331 | #ifdef _MODULE |
| 332 | mutex_enter(&sysmon_minor_mtx); |
| 333 | if (!sm_is_attached) { |
| 334 | bmajor = cmajor = -1; |
| 335 | error = devsw_attach("sysmon" , NULL, &bmajor, |
| 336 | &sysmon_cdevsw, &cmajor); |
| 337 | sm_is_attached = (error != 0); |
| 338 | } |
| 339 | mutex_exit(&sysmon_minor_mtx); |
| 340 | #endif |
| 341 | |
| 342 | return error; |
| 343 | } |
| 344 | |
| 345 | int |
| 346 | sysmon_fini(void) |
| 347 | { |
| 348 | int error = 0; |
| 349 | |
| 350 | if ((sysmon_opvec_table[SYSMON_MINOR_ENVSYS] != NULL) || |
| 351 | (sysmon_opvec_table[SYSMON_MINOR_WDOG] != NULL) || |
| 352 | (sysmon_opvec_table[SYSMON_MINOR_POWER] != NULL)) |
| 353 | error = EBUSY; |
| 354 | |
| 355 | #ifdef _MODULE |
| 356 | if (error == 0) { |
| 357 | mutex_enter(&sysmon_minor_mtx); |
| 358 | sm_is_attached = false; |
| 359 | error = devsw_detach(NULL, &sysmon_cdevsw); |
| 360 | mutex_exit(&sysmon_minor_mtx); |
| 361 | } |
| 362 | #endif |
| 363 | |
| 364 | return error; |
| 365 | } |
| 366 | |
| 367 | static |
| 368 | int |
| 369 | sysmon_modcmd(modcmd_t cmd, void *arg) |
| 370 | { |
| 371 | int ret; |
| 372 | |
| 373 | switch (cmd) { |
| 374 | case MODULE_CMD_INIT: |
| 375 | ret = sysmon_init(); |
| 376 | break; |
| 377 | |
| 378 | case MODULE_CMD_FINI: |
| 379 | ret = sysmon_fini(); |
| 380 | break; |
| 381 | |
| 382 | case MODULE_CMD_STAT: |
| 383 | default: |
| 384 | ret = ENOTTY; |
| 385 | } |
| 386 | |
| 387 | return ret; |
| 388 | } |
| 389 | |