| 1 | /* $NetBSD: sysv_sem.c,v 1.95 2015/11/06 02:26:42 pgoyette Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 1999, 2007 The NetBSD Foundation, Inc. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to The NetBSD Foundation |
| 8 | * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, |
| 9 | * NASA Ames Research Center, and by Andrew Doran. |
| 10 | * |
| 11 | * Redistribution and use in source and binary forms, with or without |
| 12 | * modification, are permitted provided that the following conditions |
| 13 | * are met: |
| 14 | * 1. Redistributions of source code must retain the above copyright |
| 15 | * notice, this list of conditions and the following disclaimer. |
| 16 | * 2. Redistributions in binary form must reproduce the above copyright |
| 17 | * notice, this list of conditions and the following disclaimer in the |
| 18 | * documentation and/or other materials provided with the distribution. |
| 19 | * |
| 20 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
| 21 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| 22 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 23 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
| 24 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 25 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 26 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 27 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 28 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 29 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 30 | * POSSIBILITY OF SUCH DAMAGE. |
| 31 | */ |
| 32 | |
| 33 | /* |
| 34 | * Implementation of SVID semaphores |
| 35 | * |
| 36 | * Author: Daniel Boulet |
| 37 | * |
| 38 | * This software is provided ``AS IS'' without any warranties of any kind. |
| 39 | */ |
| 40 | |
| 41 | #include <sys/cdefs.h> |
| 42 | __KERNEL_RCSID(0, "$NetBSD: sysv_sem.c,v 1.95 2015/11/06 02:26:42 pgoyette Exp $" ); |
| 43 | |
| 44 | #ifdef _KERNEL_OPT |
| 45 | #include "opt_sysv.h" |
| 46 | #endif |
| 47 | |
| 48 | #include <sys/param.h> |
| 49 | #include <sys/kernel.h> |
| 50 | #include <sys/sem.h> |
| 51 | #include <sys/sysctl.h> |
| 52 | #include <sys/kmem.h> |
| 53 | #include <sys/mount.h> /* XXX for <sys/syscallargs.h> */ |
| 54 | #include <sys/syscallargs.h> |
| 55 | #include <sys/kauth.h> |
| 56 | #include <sys/once.h> |
| 57 | |
| 58 | /* |
| 59 | * Memory areas: |
| 60 | * 1st: Pool of semaphore identifiers |
| 61 | * 2nd: Semaphores |
| 62 | * 3rd: Conditional variables |
| 63 | * 4th: Undo structures |
| 64 | */ |
| 65 | struct semid_ds * sema __read_mostly; |
| 66 | static struct __sem * sem __read_mostly; |
| 67 | static kcondvar_t * semcv __read_mostly; |
| 68 | static int * semu __read_mostly; |
| 69 | |
| 70 | static kmutex_t semlock __cacheline_aligned; |
| 71 | static bool sem_realloc_state __read_mostly; |
| 72 | static kcondvar_t sem_realloc_cv; |
| 73 | |
| 74 | /* |
| 75 | * List of active undo structures, total number of semaphores, |
| 76 | * and total number of semop waiters. |
| 77 | */ |
| 78 | static struct sem_undo *semu_list __read_mostly; |
| 79 | static u_int semtot __cacheline_aligned; |
| 80 | static u_int sem_waiters __cacheline_aligned; |
| 81 | |
| 82 | /* Macro to find a particular sem_undo vector */ |
| 83 | #define SEMU(s, ix) ((struct sem_undo *)(((long)s) + ix * seminfo.semusz)) |
| 84 | |
| 85 | #ifdef SEM_DEBUG |
| 86 | #define SEM_PRINTF(a) printf a |
| 87 | #else |
| 88 | #define SEM_PRINTF(a) |
| 89 | #endif |
| 90 | |
| 91 | void *hook; /* cookie from exithook_establish() */ |
| 92 | |
| 93 | extern int kern_has_sysvsem; |
| 94 | |
| 95 | SYSCTL_SETUP_PROTO(sysctl_ipc_sem_setup); |
| 96 | |
| 97 | struct sem_undo *semu_alloc(struct proc *); |
| 98 | int semundo_adjust(struct proc *, struct sem_undo **, int, int, int); |
| 99 | void semundo_clear(int, int); |
| 100 | |
| 101 | static ONCE_DECL(exithook_control); |
| 102 | static int seminit_exithook(void); |
| 103 | |
| 104 | void |
| 105 | seminit(struct sysctllog **clog) |
| 106 | { |
| 107 | int i, sz; |
| 108 | vaddr_t v; |
| 109 | |
| 110 | mutex_init(&semlock, MUTEX_DEFAULT, IPL_NONE); |
| 111 | cv_init(&sem_realloc_cv, "semrealc" ); |
| 112 | sem_realloc_state = false; |
| 113 | semtot = 0; |
| 114 | sem_waiters = 0; |
| 115 | |
| 116 | /* Allocate the wired memory for our structures */ |
| 117 | sz = ALIGN(seminfo.semmni * sizeof(struct semid_ds)) + |
| 118 | ALIGN(seminfo.semmns * sizeof(struct __sem)) + |
| 119 | ALIGN(seminfo.semmni * sizeof(kcondvar_t)) + |
| 120 | ALIGN(seminfo.semmnu * seminfo.semusz); |
| 121 | sz = round_page(sz); |
| 122 | v = uvm_km_alloc(kernel_map, sz, 0, UVM_KMF_WIRED|UVM_KMF_ZERO); |
| 123 | if (v == 0) |
| 124 | panic("sysv_sem: cannot allocate memory" ); |
| 125 | sema = (void *)v; |
| 126 | sem = (void *)((uintptr_t)sema + |
| 127 | ALIGN(seminfo.semmni * sizeof(struct semid_ds))); |
| 128 | semcv = (void *)((uintptr_t)sem + |
| 129 | ALIGN(seminfo.semmns * sizeof(struct __sem))); |
| 130 | semu = (void *)((uintptr_t)semcv + |
| 131 | ALIGN(seminfo.semmni * sizeof(kcondvar_t))); |
| 132 | |
| 133 | for (i = 0; i < seminfo.semmni; i++) { |
| 134 | sema[i]._sem_base = 0; |
| 135 | sema[i].sem_perm.mode = 0; |
| 136 | cv_init(&semcv[i], "semwait" ); |
| 137 | } |
| 138 | for (i = 0; i < seminfo.semmnu; i++) { |
| 139 | struct sem_undo *suptr = SEMU(semu, i); |
| 140 | suptr->un_proc = NULL; |
| 141 | } |
| 142 | semu_list = NULL; |
| 143 | |
| 144 | kern_has_sysvsem = 1; |
| 145 | |
| 146 | #ifdef _MODULE |
| 147 | if (clog) |
| 148 | sysctl_ipc_sem_setup(clog); |
| 149 | #endif |
| 150 | } |
| 151 | |
| 152 | static int |
| 153 | seminit_exithook(void) |
| 154 | { |
| 155 | |
| 156 | hook = exithook_establish(semexit, NULL); |
| 157 | return 0; |
| 158 | } |
| 159 | |
| 160 | int |
| 161 | semfini(void) |
| 162 | { |
| 163 | int i, sz; |
| 164 | vaddr_t v = (vaddr_t)sema; |
| 165 | |
| 166 | /* Don't allow module unload if we're busy */ |
| 167 | mutex_enter(&semlock); |
| 168 | if (semtot) { |
| 169 | mutex_exit(&semlock); |
| 170 | return 1; |
| 171 | } |
| 172 | |
| 173 | /* Remove the exit hook */ |
| 174 | if (hook) |
| 175 | exithook_disestablish(hook); |
| 176 | |
| 177 | /* Destroy all our condvars */ |
| 178 | for (i = 0; i < seminfo.semmni; i++) { |
| 179 | cv_destroy(&semcv[i]); |
| 180 | } |
| 181 | |
| 182 | /* Free the wired memory that we allocated */ |
| 183 | sz = ALIGN(seminfo.semmni * sizeof(struct semid_ds)) + |
| 184 | ALIGN(seminfo.semmns * sizeof(struct __sem)) + |
| 185 | ALIGN(seminfo.semmni * sizeof(kcondvar_t)) + |
| 186 | ALIGN(seminfo.semmnu * seminfo.semusz); |
| 187 | sz = round_page(sz); |
| 188 | uvm_km_free(kernel_map, v, sz, UVM_KMF_WIRED); |
| 189 | |
| 190 | /* Destroy the last cv and mutex */ |
| 191 | cv_destroy(&sem_realloc_cv); |
| 192 | mutex_exit(&semlock); |
| 193 | mutex_destroy(&semlock); |
| 194 | |
| 195 | kern_has_sysvsem = 0; |
| 196 | |
| 197 | return 0; |
| 198 | } |
| 199 | |
| 200 | static int |
| 201 | semrealloc(int newsemmni, int newsemmns, int newsemmnu) |
| 202 | { |
| 203 | struct semid_ds *new_sema, *old_sema; |
| 204 | struct __sem *new_sem; |
| 205 | struct sem_undo *new_semu_list, *suptr, *nsuptr; |
| 206 | int *new_semu; |
| 207 | kcondvar_t *new_semcv; |
| 208 | vaddr_t v; |
| 209 | int i, j, lsemid, nmnus, sz; |
| 210 | |
| 211 | if (newsemmni < 1 || newsemmns < 1 || newsemmnu < 1) |
| 212 | return EINVAL; |
| 213 | |
| 214 | /* Allocate the wired memory for our structures */ |
| 215 | sz = ALIGN(newsemmni * sizeof(struct semid_ds)) + |
| 216 | ALIGN(newsemmns * sizeof(struct __sem)) + |
| 217 | ALIGN(newsemmni * sizeof(kcondvar_t)) + |
| 218 | ALIGN(newsemmnu * seminfo.semusz); |
| 219 | sz = round_page(sz); |
| 220 | v = uvm_km_alloc(kernel_map, sz, 0, UVM_KMF_WIRED|UVM_KMF_ZERO); |
| 221 | if (v == 0) |
| 222 | return ENOMEM; |
| 223 | |
| 224 | mutex_enter(&semlock); |
| 225 | if (sem_realloc_state) { |
| 226 | mutex_exit(&semlock); |
| 227 | uvm_km_free(kernel_map, v, sz, UVM_KMF_WIRED); |
| 228 | return EBUSY; |
| 229 | } |
| 230 | sem_realloc_state = true; |
| 231 | if (sem_waiters) { |
| 232 | /* |
| 233 | * Mark reallocation state, wake-up all waiters, |
| 234 | * and wait while they will all exit. |
| 235 | */ |
| 236 | for (i = 0; i < seminfo.semmni; i++) |
| 237 | cv_broadcast(&semcv[i]); |
| 238 | while (sem_waiters) |
| 239 | cv_wait(&sem_realloc_cv, &semlock); |
| 240 | } |
| 241 | old_sema = sema; |
| 242 | |
| 243 | /* Get the number of last slot */ |
| 244 | lsemid = 0; |
| 245 | for (i = 0; i < seminfo.semmni; i++) |
| 246 | if (sema[i].sem_perm.mode & SEM_ALLOC) |
| 247 | lsemid = i; |
| 248 | |
| 249 | /* Get the number of currently used undo structures */ |
| 250 | nmnus = 0; |
| 251 | for (i = 0; i < seminfo.semmnu; i++) { |
| 252 | suptr = SEMU(semu, i); |
| 253 | if (suptr->un_proc == NULL) |
| 254 | continue; |
| 255 | nmnus++; |
| 256 | } |
| 257 | |
| 258 | /* We cannot reallocate less memory than we use */ |
| 259 | if (lsemid >= newsemmni || semtot > newsemmns || nmnus > newsemmnu) { |
| 260 | mutex_exit(&semlock); |
| 261 | uvm_km_free(kernel_map, v, sz, UVM_KMF_WIRED); |
| 262 | return EBUSY; |
| 263 | } |
| 264 | |
| 265 | new_sema = (void *)v; |
| 266 | new_sem = (void *)((uintptr_t)new_sema + |
| 267 | ALIGN(newsemmni * sizeof(struct semid_ds))); |
| 268 | new_semcv = (void *)((uintptr_t)new_sem + |
| 269 | ALIGN(newsemmns * sizeof(struct __sem))); |
| 270 | new_semu = (void *)((uintptr_t)new_semcv + |
| 271 | ALIGN(newsemmni * sizeof(kcondvar_t))); |
| 272 | |
| 273 | /* Initialize all semaphore identifiers and condvars */ |
| 274 | for (i = 0; i < newsemmni; i++) { |
| 275 | new_sema[i]._sem_base = 0; |
| 276 | new_sema[i].sem_perm.mode = 0; |
| 277 | cv_init(&new_semcv[i], "semwait" ); |
| 278 | } |
| 279 | for (i = 0; i < newsemmnu; i++) { |
| 280 | nsuptr = SEMU(new_semu, i); |
| 281 | nsuptr->un_proc = NULL; |
| 282 | } |
| 283 | |
| 284 | /* |
| 285 | * Copy all identifiers, semaphores and list of the |
| 286 | * undo structures to the new memory allocation. |
| 287 | */ |
| 288 | j = 0; |
| 289 | for (i = 0; i <= lsemid; i++) { |
| 290 | if ((sema[i].sem_perm.mode & SEM_ALLOC) == 0) |
| 291 | continue; |
| 292 | memcpy(&new_sema[i], &sema[i], sizeof(struct semid_ds)); |
| 293 | new_sema[i]._sem_base = &new_sem[j]; |
| 294 | memcpy(new_sema[i]._sem_base, sema[i]._sem_base, |
| 295 | (sizeof(struct __sem) * sema[i].sem_nsems)); |
| 296 | j += sema[i].sem_nsems; |
| 297 | } |
| 298 | KASSERT(j == semtot); |
| 299 | |
| 300 | j = 0; |
| 301 | new_semu_list = NULL; |
| 302 | for (suptr = semu_list; suptr != NULL; suptr = suptr->un_next) { |
| 303 | KASSERT(j < newsemmnu); |
| 304 | nsuptr = SEMU(new_semu, j); |
| 305 | memcpy(nsuptr, suptr, SEMUSZ); |
| 306 | nsuptr->un_next = new_semu_list; |
| 307 | new_semu_list = nsuptr; |
| 308 | j++; |
| 309 | } |
| 310 | |
| 311 | for (i = 0; i < seminfo.semmni; i++) { |
| 312 | KASSERT(cv_has_waiters(&semcv[i]) == false); |
| 313 | cv_destroy(&semcv[i]); |
| 314 | } |
| 315 | |
| 316 | sz = ALIGN(seminfo.semmni * sizeof(struct semid_ds)) + |
| 317 | ALIGN(seminfo.semmns * sizeof(struct __sem)) + |
| 318 | ALIGN(seminfo.semmni * sizeof(kcondvar_t)) + |
| 319 | ALIGN(seminfo.semmnu * seminfo.semusz); |
| 320 | sz = round_page(sz); |
| 321 | |
| 322 | /* Set the pointers and update the new values */ |
| 323 | sema = new_sema; |
| 324 | sem = new_sem; |
| 325 | semcv = new_semcv; |
| 326 | semu = new_semu; |
| 327 | semu_list = new_semu_list; |
| 328 | |
| 329 | seminfo.semmni = newsemmni; |
| 330 | seminfo.semmns = newsemmns; |
| 331 | seminfo.semmnu = newsemmnu; |
| 332 | |
| 333 | /* Reallocation completed - notify all waiters, if any */ |
| 334 | sem_realloc_state = false; |
| 335 | cv_broadcast(&sem_realloc_cv); |
| 336 | mutex_exit(&semlock); |
| 337 | |
| 338 | uvm_km_free(kernel_map, (vaddr_t)old_sema, sz, UVM_KMF_WIRED); |
| 339 | return 0; |
| 340 | } |
| 341 | |
| 342 | /* |
| 343 | * Placebo. |
| 344 | */ |
| 345 | |
| 346 | int |
| 347 | sys_semconfig(struct lwp *l, const struct sys_semconfig_args *uap, register_t *retval) |
| 348 | { |
| 349 | |
| 350 | RUN_ONCE(&exithook_control, seminit_exithook); |
| 351 | |
| 352 | *retval = 0; |
| 353 | return 0; |
| 354 | } |
| 355 | |
| 356 | /* |
| 357 | * Allocate a new sem_undo structure for a process. |
| 358 | * => Returns NULL on failure. |
| 359 | */ |
| 360 | struct sem_undo * |
| 361 | semu_alloc(struct proc *p) |
| 362 | { |
| 363 | struct sem_undo *suptr, **supptr; |
| 364 | bool attempted = false; |
| 365 | int i; |
| 366 | |
| 367 | KASSERT(mutex_owned(&semlock)); |
| 368 | again: |
| 369 | /* Look for a free structure. */ |
| 370 | for (i = 0; i < seminfo.semmnu; i++) { |
| 371 | suptr = SEMU(semu, i); |
| 372 | if (suptr->un_proc == NULL) { |
| 373 | /* Found. Fill it in and return. */ |
| 374 | suptr->un_next = semu_list; |
| 375 | semu_list = suptr; |
| 376 | suptr->un_cnt = 0; |
| 377 | suptr->un_proc = p; |
| 378 | return suptr; |
| 379 | } |
| 380 | } |
| 381 | |
| 382 | /* Not found. Attempt to free some structures. */ |
| 383 | if (!attempted) { |
| 384 | bool freed = false; |
| 385 | |
| 386 | attempted = true; |
| 387 | supptr = &semu_list; |
| 388 | while ((suptr = *supptr) != NULL) { |
| 389 | if (suptr->un_cnt == 0) { |
| 390 | suptr->un_proc = NULL; |
| 391 | *supptr = suptr->un_next; |
| 392 | freed = true; |
| 393 | } else { |
| 394 | supptr = &suptr->un_next; |
| 395 | } |
| 396 | } |
| 397 | if (freed) { |
| 398 | goto again; |
| 399 | } |
| 400 | } |
| 401 | return NULL; |
| 402 | } |
| 403 | |
| 404 | /* |
| 405 | * Adjust a particular entry for a particular proc |
| 406 | */ |
| 407 | |
| 408 | int |
| 409 | semundo_adjust(struct proc *p, struct sem_undo **supptr, int semid, int semnum, |
| 410 | int adjval) |
| 411 | { |
| 412 | struct sem_undo *suptr; |
| 413 | struct sem_undo_entry *sunptr; |
| 414 | int i; |
| 415 | |
| 416 | KASSERT(mutex_owned(&semlock)); |
| 417 | |
| 418 | /* |
| 419 | * Look for and remember the sem_undo if the caller doesn't |
| 420 | * provide it |
| 421 | */ |
| 422 | |
| 423 | suptr = *supptr; |
| 424 | if (suptr == NULL) { |
| 425 | for (suptr = semu_list; suptr != NULL; suptr = suptr->un_next) |
| 426 | if (suptr->un_proc == p) |
| 427 | break; |
| 428 | |
| 429 | if (suptr == NULL) { |
| 430 | suptr = semu_alloc(p); |
| 431 | if (suptr == NULL) |
| 432 | return (ENOSPC); |
| 433 | } |
| 434 | *supptr = suptr; |
| 435 | } |
| 436 | |
| 437 | /* |
| 438 | * Look for the requested entry and adjust it (delete if |
| 439 | * adjval becomes 0). |
| 440 | */ |
| 441 | sunptr = &suptr->un_ent[0]; |
| 442 | for (i = 0; i < suptr->un_cnt; i++, sunptr++) { |
| 443 | if (sunptr->un_id != semid || sunptr->un_num != semnum) |
| 444 | continue; |
| 445 | sunptr->un_adjval += adjval; |
| 446 | if (sunptr->un_adjval == 0) { |
| 447 | suptr->un_cnt--; |
| 448 | if (i < suptr->un_cnt) |
| 449 | suptr->un_ent[i] = |
| 450 | suptr->un_ent[suptr->un_cnt]; |
| 451 | } |
| 452 | return (0); |
| 453 | } |
| 454 | |
| 455 | /* Didn't find the right entry - create it */ |
| 456 | if (suptr->un_cnt == SEMUME) |
| 457 | return (EINVAL); |
| 458 | |
| 459 | sunptr = &suptr->un_ent[suptr->un_cnt]; |
| 460 | suptr->un_cnt++; |
| 461 | sunptr->un_adjval = adjval; |
| 462 | sunptr->un_id = semid; |
| 463 | sunptr->un_num = semnum; |
| 464 | return (0); |
| 465 | } |
| 466 | |
| 467 | void |
| 468 | semundo_clear(int semid, int semnum) |
| 469 | { |
| 470 | struct sem_undo *suptr; |
| 471 | struct sem_undo_entry *sunptr, *sunend; |
| 472 | |
| 473 | KASSERT(mutex_owned(&semlock)); |
| 474 | |
| 475 | for (suptr = semu_list; suptr != NULL; suptr = suptr->un_next) |
| 476 | for (sunptr = &suptr->un_ent[0], |
| 477 | sunend = sunptr + suptr->un_cnt; sunptr < sunend;) { |
| 478 | if (sunptr->un_id == semid) { |
| 479 | if (semnum == -1 || sunptr->un_num == semnum) { |
| 480 | suptr->un_cnt--; |
| 481 | sunend--; |
| 482 | if (sunptr != sunend) |
| 483 | *sunptr = *sunend; |
| 484 | if (semnum != -1) |
| 485 | break; |
| 486 | else |
| 487 | continue; |
| 488 | } |
| 489 | } |
| 490 | sunptr++; |
| 491 | } |
| 492 | } |
| 493 | |
| 494 | int |
| 495 | sys_____semctl50(struct lwp *l, const struct sys_____semctl50_args *uap, |
| 496 | register_t *retval) |
| 497 | { |
| 498 | /* { |
| 499 | syscallarg(int) semid; |
| 500 | syscallarg(int) semnum; |
| 501 | syscallarg(int) cmd; |
| 502 | syscallarg(union __semun *) arg; |
| 503 | } */ |
| 504 | struct semid_ds sembuf; |
| 505 | int cmd, error; |
| 506 | void *pass_arg; |
| 507 | union __semun karg; |
| 508 | |
| 509 | RUN_ONCE(&exithook_control, seminit_exithook); |
| 510 | |
| 511 | cmd = SCARG(uap, cmd); |
| 512 | |
| 513 | pass_arg = get_semctl_arg(cmd, &sembuf, &karg); |
| 514 | |
| 515 | if (pass_arg) { |
| 516 | error = copyin(SCARG(uap, arg), &karg, sizeof(karg)); |
| 517 | if (error) |
| 518 | return error; |
| 519 | if (cmd == IPC_SET) { |
| 520 | error = copyin(karg.buf, &sembuf, sizeof(sembuf)); |
| 521 | if (error) |
| 522 | return (error); |
| 523 | } |
| 524 | } |
| 525 | |
| 526 | error = semctl1(l, SCARG(uap, semid), SCARG(uap, semnum), cmd, |
| 527 | pass_arg, retval); |
| 528 | |
| 529 | if (error == 0 && cmd == IPC_STAT) |
| 530 | error = copyout(&sembuf, karg.buf, sizeof(sembuf)); |
| 531 | |
| 532 | return (error); |
| 533 | } |
| 534 | |
| 535 | int |
| 536 | semctl1(struct lwp *l, int semid, int semnum, int cmd, void *v, |
| 537 | register_t *retval) |
| 538 | { |
| 539 | kauth_cred_t cred = l->l_cred; |
| 540 | union __semun *arg = v; |
| 541 | struct semid_ds *sembuf = v, *semaptr; |
| 542 | int i, error, ix; |
| 543 | |
| 544 | SEM_PRINTF(("call to semctl(%d, %d, %d, %p)\n" , |
| 545 | semid, semnum, cmd, v)); |
| 546 | |
| 547 | mutex_enter(&semlock); |
| 548 | |
| 549 | ix = IPCID_TO_IX(semid); |
| 550 | if (ix < 0 || ix >= seminfo.semmni) { |
| 551 | mutex_exit(&semlock); |
| 552 | return (EINVAL); |
| 553 | } |
| 554 | |
| 555 | semaptr = &sema[ix]; |
| 556 | if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0 || |
| 557 | semaptr->sem_perm._seq != IPCID_TO_SEQ(semid)) { |
| 558 | mutex_exit(&semlock); |
| 559 | return (EINVAL); |
| 560 | } |
| 561 | |
| 562 | switch (cmd) { |
| 563 | case IPC_RMID: |
| 564 | if ((error = ipcperm(cred, &semaptr->sem_perm, IPC_M)) != 0) |
| 565 | break; |
| 566 | semaptr->sem_perm.cuid = kauth_cred_geteuid(cred); |
| 567 | semaptr->sem_perm.uid = kauth_cred_geteuid(cred); |
| 568 | semtot -= semaptr->sem_nsems; |
| 569 | for (i = semaptr->_sem_base - sem; i < semtot; i++) |
| 570 | sem[i] = sem[i + semaptr->sem_nsems]; |
| 571 | for (i = 0; i < seminfo.semmni; i++) { |
| 572 | if ((sema[i].sem_perm.mode & SEM_ALLOC) && |
| 573 | sema[i]._sem_base > semaptr->_sem_base) |
| 574 | sema[i]._sem_base -= semaptr->sem_nsems; |
| 575 | } |
| 576 | semaptr->sem_perm.mode = 0; |
| 577 | semundo_clear(ix, -1); |
| 578 | cv_broadcast(&semcv[ix]); |
| 579 | break; |
| 580 | |
| 581 | case IPC_SET: |
| 582 | if ((error = ipcperm(cred, &semaptr->sem_perm, IPC_M))) |
| 583 | break; |
| 584 | KASSERT(sembuf != NULL); |
| 585 | semaptr->sem_perm.uid = sembuf->sem_perm.uid; |
| 586 | semaptr->sem_perm.gid = sembuf->sem_perm.gid; |
| 587 | semaptr->sem_perm.mode = (semaptr->sem_perm.mode & ~0777) | |
| 588 | (sembuf->sem_perm.mode & 0777); |
| 589 | semaptr->sem_ctime = time_second; |
| 590 | break; |
| 591 | |
| 592 | case IPC_STAT: |
| 593 | if ((error = ipcperm(cred, &semaptr->sem_perm, IPC_R))) |
| 594 | break; |
| 595 | KASSERT(sembuf != NULL); |
| 596 | memcpy(sembuf, semaptr, sizeof(struct semid_ds)); |
| 597 | sembuf->sem_perm.mode &= 0777; |
| 598 | break; |
| 599 | |
| 600 | case GETNCNT: |
| 601 | if ((error = ipcperm(cred, &semaptr->sem_perm, IPC_R))) |
| 602 | break; |
| 603 | if (semnum < 0 || semnum >= semaptr->sem_nsems) { |
| 604 | error = EINVAL; |
| 605 | break; |
| 606 | } |
| 607 | *retval = semaptr->_sem_base[semnum].semncnt; |
| 608 | break; |
| 609 | |
| 610 | case GETPID: |
| 611 | if ((error = ipcperm(cred, &semaptr->sem_perm, IPC_R))) |
| 612 | break; |
| 613 | if (semnum < 0 || semnum >= semaptr->sem_nsems) { |
| 614 | error = EINVAL; |
| 615 | break; |
| 616 | } |
| 617 | *retval = semaptr->_sem_base[semnum].sempid; |
| 618 | break; |
| 619 | |
| 620 | case GETVAL: |
| 621 | if ((error = ipcperm(cred, &semaptr->sem_perm, IPC_R))) |
| 622 | break; |
| 623 | if (semnum < 0 || semnum >= semaptr->sem_nsems) { |
| 624 | error = EINVAL; |
| 625 | break; |
| 626 | } |
| 627 | *retval = semaptr->_sem_base[semnum].semval; |
| 628 | break; |
| 629 | |
| 630 | case GETALL: |
| 631 | if ((error = ipcperm(cred, &semaptr->sem_perm, IPC_R))) |
| 632 | break; |
| 633 | KASSERT(arg != NULL); |
| 634 | for (i = 0; i < semaptr->sem_nsems; i++) { |
| 635 | error = copyout(&semaptr->_sem_base[i].semval, |
| 636 | &arg->array[i], sizeof(arg->array[i])); |
| 637 | if (error != 0) |
| 638 | break; |
| 639 | } |
| 640 | break; |
| 641 | |
| 642 | case GETZCNT: |
| 643 | if ((error = ipcperm(cred, &semaptr->sem_perm, IPC_R))) |
| 644 | break; |
| 645 | if (semnum < 0 || semnum >= semaptr->sem_nsems) { |
| 646 | error = EINVAL; |
| 647 | break; |
| 648 | } |
| 649 | *retval = semaptr->_sem_base[semnum].semzcnt; |
| 650 | break; |
| 651 | |
| 652 | case SETVAL: |
| 653 | if ((error = ipcperm(cred, &semaptr->sem_perm, IPC_W))) |
| 654 | break; |
| 655 | if (semnum < 0 || semnum >= semaptr->sem_nsems) { |
| 656 | error = EINVAL; |
| 657 | break; |
| 658 | } |
| 659 | KASSERT(arg != NULL); |
| 660 | if ((unsigned int)arg->val > seminfo.semvmx) { |
| 661 | error = ERANGE; |
| 662 | break; |
| 663 | } |
| 664 | semaptr->_sem_base[semnum].semval = arg->val; |
| 665 | semundo_clear(ix, semnum); |
| 666 | cv_broadcast(&semcv[ix]); |
| 667 | break; |
| 668 | |
| 669 | case SETALL: |
| 670 | if ((error = ipcperm(cred, &semaptr->sem_perm, IPC_W))) |
| 671 | break; |
| 672 | KASSERT(arg != NULL); |
| 673 | for (i = 0; i < semaptr->sem_nsems; i++) { |
| 674 | unsigned short semval; |
| 675 | error = copyin(&arg->array[i], &semval, |
| 676 | sizeof(arg->array[i])); |
| 677 | if (error != 0) |
| 678 | break; |
| 679 | if ((unsigned int)semval > seminfo.semvmx) { |
| 680 | error = ERANGE; |
| 681 | break; |
| 682 | } |
| 683 | semaptr->_sem_base[i].semval = semval; |
| 684 | } |
| 685 | semundo_clear(ix, -1); |
| 686 | cv_broadcast(&semcv[ix]); |
| 687 | break; |
| 688 | |
| 689 | default: |
| 690 | error = EINVAL; |
| 691 | break; |
| 692 | } |
| 693 | |
| 694 | mutex_exit(&semlock); |
| 695 | return (error); |
| 696 | } |
| 697 | |
| 698 | int |
| 699 | sys_semget(struct lwp *l, const struct sys_semget_args *uap, register_t *retval) |
| 700 | { |
| 701 | /* { |
| 702 | syscallarg(key_t) key; |
| 703 | syscallarg(int) nsems; |
| 704 | syscallarg(int) semflg; |
| 705 | } */ |
| 706 | int semid, error = 0; |
| 707 | int key = SCARG(uap, key); |
| 708 | int nsems = SCARG(uap, nsems); |
| 709 | int semflg = SCARG(uap, semflg); |
| 710 | kauth_cred_t cred = l->l_cred; |
| 711 | |
| 712 | RUN_ONCE(&exithook_control, seminit_exithook); |
| 713 | |
| 714 | SEM_PRINTF(("semget(0x%x, %d, 0%o)\n" , key, nsems, semflg)); |
| 715 | |
| 716 | mutex_enter(&semlock); |
| 717 | |
| 718 | if (key != IPC_PRIVATE) { |
| 719 | for (semid = 0; semid < seminfo.semmni; semid++) { |
| 720 | if ((sema[semid].sem_perm.mode & SEM_ALLOC) && |
| 721 | sema[semid].sem_perm._key == key) |
| 722 | break; |
| 723 | } |
| 724 | if (semid < seminfo.semmni) { |
| 725 | SEM_PRINTF(("found public key\n" )); |
| 726 | if ((error = ipcperm(cred, &sema[semid].sem_perm, |
| 727 | semflg & 0700))) |
| 728 | goto out; |
| 729 | if (nsems > 0 && sema[semid].sem_nsems < nsems) { |
| 730 | SEM_PRINTF(("too small\n" )); |
| 731 | error = EINVAL; |
| 732 | goto out; |
| 733 | } |
| 734 | if ((semflg & IPC_CREAT) && (semflg & IPC_EXCL)) { |
| 735 | SEM_PRINTF(("not exclusive\n" )); |
| 736 | error = EEXIST; |
| 737 | goto out; |
| 738 | } |
| 739 | goto found; |
| 740 | } |
| 741 | } |
| 742 | |
| 743 | SEM_PRINTF(("need to allocate the semid_ds\n" )); |
| 744 | if (key == IPC_PRIVATE || (semflg & IPC_CREAT)) { |
| 745 | if (nsems <= 0 || nsems > seminfo.semmsl) { |
| 746 | SEM_PRINTF(("nsems out of range (0<%d<=%d)\n" , nsems, |
| 747 | seminfo.semmsl)); |
| 748 | error = EINVAL; |
| 749 | goto out; |
| 750 | } |
| 751 | if (nsems > seminfo.semmns - semtot) { |
| 752 | SEM_PRINTF(("not enough semaphores left " |
| 753 | "(need %d, got %d)\n" , |
| 754 | nsems, seminfo.semmns - semtot)); |
| 755 | error = ENOSPC; |
| 756 | goto out; |
| 757 | } |
| 758 | for (semid = 0; semid < seminfo.semmni; semid++) { |
| 759 | if ((sema[semid].sem_perm.mode & SEM_ALLOC) == 0) |
| 760 | break; |
| 761 | } |
| 762 | if (semid == seminfo.semmni) { |
| 763 | SEM_PRINTF(("no more semid_ds's available\n" )); |
| 764 | error = ENOSPC; |
| 765 | goto out; |
| 766 | } |
| 767 | SEM_PRINTF(("semid %d is available\n" , semid)); |
| 768 | sema[semid].sem_perm._key = key; |
| 769 | sema[semid].sem_perm.cuid = kauth_cred_geteuid(cred); |
| 770 | sema[semid].sem_perm.uid = kauth_cred_geteuid(cred); |
| 771 | sema[semid].sem_perm.cgid = kauth_cred_getegid(cred); |
| 772 | sema[semid].sem_perm.gid = kauth_cred_getegid(cred); |
| 773 | sema[semid].sem_perm.mode = (semflg & 0777) | SEM_ALLOC; |
| 774 | sema[semid].sem_perm._seq = |
| 775 | (sema[semid].sem_perm._seq + 1) & 0x7fff; |
| 776 | sema[semid].sem_nsems = nsems; |
| 777 | sema[semid].sem_otime = 0; |
| 778 | sema[semid].sem_ctime = time_second; |
| 779 | sema[semid]._sem_base = &sem[semtot]; |
| 780 | semtot += nsems; |
| 781 | memset(sema[semid]._sem_base, 0, |
| 782 | sizeof(sema[semid]._sem_base[0]) * nsems); |
| 783 | SEM_PRINTF(("sembase = %p, next = %p\n" , sema[semid]._sem_base, |
| 784 | &sem[semtot])); |
| 785 | } else { |
| 786 | SEM_PRINTF(("didn't find it and wasn't asked to create it\n" )); |
| 787 | error = ENOENT; |
| 788 | goto out; |
| 789 | } |
| 790 | |
| 791 | found: |
| 792 | *retval = IXSEQ_TO_IPCID(semid, sema[semid].sem_perm); |
| 793 | out: |
| 794 | mutex_exit(&semlock); |
| 795 | return (error); |
| 796 | } |
| 797 | |
| 798 | #define SMALL_SOPS 8 |
| 799 | |
| 800 | int |
| 801 | sys_semop(struct lwp *l, const struct sys_semop_args *uap, register_t *retval) |
| 802 | { |
| 803 | /* { |
| 804 | syscallarg(int) semid; |
| 805 | syscallarg(struct sembuf *) sops; |
| 806 | syscallarg(size_t) nsops; |
| 807 | } */ |
| 808 | struct proc *p = l->l_proc; |
| 809 | int semid = SCARG(uap, semid), seq; |
| 810 | size_t nsops = SCARG(uap, nsops); |
| 811 | struct sembuf small_sops[SMALL_SOPS]; |
| 812 | struct sembuf *sops; |
| 813 | struct semid_ds *semaptr; |
| 814 | struct sembuf *sopptr = NULL; |
| 815 | struct __sem *semptr = NULL; |
| 816 | struct sem_undo *suptr = NULL; |
| 817 | kauth_cred_t cred = l->l_cred; |
| 818 | int i, error; |
| 819 | int do_wakeup, do_undos; |
| 820 | |
| 821 | RUN_ONCE(&exithook_control, seminit_exithook); |
| 822 | |
| 823 | SEM_PRINTF(("call to semop(%d, %p, %zd)\n" , semid, SCARG(uap,sops), nsops)); |
| 824 | |
| 825 | if (__predict_false((p->p_flag & PK_SYSVSEM) == 0)) { |
| 826 | mutex_enter(p->p_lock); |
| 827 | p->p_flag |= PK_SYSVSEM; |
| 828 | mutex_exit(p->p_lock); |
| 829 | } |
| 830 | |
| 831 | restart: |
| 832 | if (nsops <= SMALL_SOPS) { |
| 833 | sops = small_sops; |
| 834 | } else if (nsops <= seminfo.semopm) { |
| 835 | sops = kmem_alloc(nsops * sizeof(*sops), KM_SLEEP); |
| 836 | } else { |
| 837 | SEM_PRINTF(("too many sops (max=%d, nsops=%zd)\n" , |
| 838 | seminfo.semopm, nsops)); |
| 839 | return (E2BIG); |
| 840 | } |
| 841 | |
| 842 | error = copyin(SCARG(uap, sops), sops, nsops * sizeof(sops[0])); |
| 843 | if (error) { |
| 844 | SEM_PRINTF(("error = %d from copyin(%p, %p, %zd)\n" , error, |
| 845 | SCARG(uap, sops), &sops, nsops * sizeof(sops[0]))); |
| 846 | if (sops != small_sops) |
| 847 | kmem_free(sops, nsops * sizeof(*sops)); |
| 848 | return error; |
| 849 | } |
| 850 | |
| 851 | mutex_enter(&semlock); |
| 852 | /* In case of reallocation, we will wait for completion */ |
| 853 | while (__predict_false(sem_realloc_state)) |
| 854 | cv_wait(&sem_realloc_cv, &semlock); |
| 855 | |
| 856 | semid = IPCID_TO_IX(semid); /* Convert back to zero origin */ |
| 857 | if (semid < 0 || semid >= seminfo.semmni) { |
| 858 | error = EINVAL; |
| 859 | goto out; |
| 860 | } |
| 861 | |
| 862 | semaptr = &sema[semid]; |
| 863 | seq = IPCID_TO_SEQ(SCARG(uap, semid)); |
| 864 | if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0 || |
| 865 | semaptr->sem_perm._seq != seq) { |
| 866 | error = EINVAL; |
| 867 | goto out; |
| 868 | } |
| 869 | |
| 870 | if ((error = ipcperm(cred, &semaptr->sem_perm, IPC_W))) { |
| 871 | SEM_PRINTF(("error = %d from ipaccess\n" , error)); |
| 872 | goto out; |
| 873 | } |
| 874 | |
| 875 | for (i = 0; i < nsops; i++) |
| 876 | if (sops[i].sem_num >= semaptr->sem_nsems) { |
| 877 | error = EFBIG; |
| 878 | goto out; |
| 879 | } |
| 880 | |
| 881 | /* |
| 882 | * Loop trying to satisfy the vector of requests. |
| 883 | * If we reach a point where we must wait, any requests already |
| 884 | * performed are rolled back and we go to sleep until some other |
| 885 | * process wakes us up. At this point, we start all over again. |
| 886 | * |
| 887 | * This ensures that from the perspective of other tasks, a set |
| 888 | * of requests is atomic (never partially satisfied). |
| 889 | */ |
| 890 | do_undos = 0; |
| 891 | |
| 892 | for (;;) { |
| 893 | do_wakeup = 0; |
| 894 | |
| 895 | for (i = 0; i < nsops; i++) { |
| 896 | sopptr = &sops[i]; |
| 897 | semptr = &semaptr->_sem_base[sopptr->sem_num]; |
| 898 | |
| 899 | SEM_PRINTF(("semop: semaptr=%p, sem_base=%p, " |
| 900 | "semptr=%p, sem[%d]=%d : op=%d, flag=%s\n" , |
| 901 | semaptr, semaptr->_sem_base, semptr, |
| 902 | sopptr->sem_num, semptr->semval, sopptr->sem_op, |
| 903 | (sopptr->sem_flg & IPC_NOWAIT) ? |
| 904 | "nowait" : "wait" )); |
| 905 | |
| 906 | if (sopptr->sem_op < 0) { |
| 907 | if ((int)(semptr->semval + |
| 908 | sopptr->sem_op) < 0) { |
| 909 | SEM_PRINTF(("semop: " |
| 910 | "can't do it now\n" )); |
| 911 | break; |
| 912 | } else { |
| 913 | semptr->semval += sopptr->sem_op; |
| 914 | if (semptr->semval == 0 && |
| 915 | semptr->semzcnt > 0) |
| 916 | do_wakeup = 1; |
| 917 | } |
| 918 | if (sopptr->sem_flg & SEM_UNDO) |
| 919 | do_undos = 1; |
| 920 | } else if (sopptr->sem_op == 0) { |
| 921 | if (semptr->semval > 0) { |
| 922 | SEM_PRINTF(("semop: not zero now\n" )); |
| 923 | break; |
| 924 | } |
| 925 | } else { |
| 926 | if (semptr->semncnt > 0) |
| 927 | do_wakeup = 1; |
| 928 | semptr->semval += sopptr->sem_op; |
| 929 | if (sopptr->sem_flg & SEM_UNDO) |
| 930 | do_undos = 1; |
| 931 | } |
| 932 | } |
| 933 | |
| 934 | /* |
| 935 | * Did we get through the entire vector? |
| 936 | */ |
| 937 | if (i >= nsops) |
| 938 | goto done; |
| 939 | |
| 940 | /* |
| 941 | * No ... rollback anything that we've already done |
| 942 | */ |
| 943 | SEM_PRINTF(("semop: rollback 0 through %d\n" , i - 1)); |
| 944 | while (i-- > 0) |
| 945 | semaptr->_sem_base[sops[i].sem_num].semval -= |
| 946 | sops[i].sem_op; |
| 947 | |
| 948 | /* |
| 949 | * If the request that we couldn't satisfy has the |
| 950 | * NOWAIT flag set then return with EAGAIN. |
| 951 | */ |
| 952 | if (sopptr->sem_flg & IPC_NOWAIT) { |
| 953 | error = EAGAIN; |
| 954 | goto out; |
| 955 | } |
| 956 | |
| 957 | if (sopptr->sem_op == 0) |
| 958 | semptr->semzcnt++; |
| 959 | else |
| 960 | semptr->semncnt++; |
| 961 | |
| 962 | sem_waiters++; |
| 963 | SEM_PRINTF(("semop: good night!\n" )); |
| 964 | error = cv_wait_sig(&semcv[semid], &semlock); |
| 965 | SEM_PRINTF(("semop: good morning (error=%d)!\n" , error)); |
| 966 | sem_waiters--; |
| 967 | |
| 968 | /* Notify reallocator, if it is waiting */ |
| 969 | cv_broadcast(&sem_realloc_cv); |
| 970 | |
| 971 | /* |
| 972 | * Make sure that the semaphore still exists |
| 973 | */ |
| 974 | if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0 || |
| 975 | semaptr->sem_perm._seq != seq) { |
| 976 | error = EIDRM; |
| 977 | goto out; |
| 978 | } |
| 979 | |
| 980 | /* |
| 981 | * The semaphore is still alive. Readjust the count of |
| 982 | * waiting processes. |
| 983 | */ |
| 984 | semptr = &semaptr->_sem_base[sopptr->sem_num]; |
| 985 | if (sopptr->sem_op == 0) |
| 986 | semptr->semzcnt--; |
| 987 | else |
| 988 | semptr->semncnt--; |
| 989 | |
| 990 | /* In case of such state, restart the call */ |
| 991 | if (sem_realloc_state) { |
| 992 | mutex_exit(&semlock); |
| 993 | goto restart; |
| 994 | } |
| 995 | |
| 996 | /* Is it really morning, or was our sleep interrupted? */ |
| 997 | if (error != 0) { |
| 998 | error = EINTR; |
| 999 | goto out; |
| 1000 | } |
| 1001 | SEM_PRINTF(("semop: good morning!\n" )); |
| 1002 | } |
| 1003 | |
| 1004 | done: |
| 1005 | /* |
| 1006 | * Process any SEM_UNDO requests. |
| 1007 | */ |
| 1008 | if (do_undos) { |
| 1009 | for (i = 0; i < nsops; i++) { |
| 1010 | /* |
| 1011 | * We only need to deal with SEM_UNDO's for non-zero |
| 1012 | * op's. |
| 1013 | */ |
| 1014 | int adjval; |
| 1015 | |
| 1016 | if ((sops[i].sem_flg & SEM_UNDO) == 0) |
| 1017 | continue; |
| 1018 | adjval = sops[i].sem_op; |
| 1019 | if (adjval == 0) |
| 1020 | continue; |
| 1021 | error = semundo_adjust(p, &suptr, semid, |
| 1022 | sops[i].sem_num, -adjval); |
| 1023 | if (error == 0) |
| 1024 | continue; |
| 1025 | |
| 1026 | /* |
| 1027 | * Oh-Oh! We ran out of either sem_undo's or undo's. |
| 1028 | * Rollback the adjustments to this point and then |
| 1029 | * rollback the semaphore ups and down so we can return |
| 1030 | * with an error with all structures restored. We |
| 1031 | * rollback the undo's in the exact reverse order that |
| 1032 | * we applied them. This guarantees that we won't run |
| 1033 | * out of space as we roll things back out. |
| 1034 | */ |
| 1035 | while (i-- > 0) { |
| 1036 | if ((sops[i].sem_flg & SEM_UNDO) == 0) |
| 1037 | continue; |
| 1038 | adjval = sops[i].sem_op; |
| 1039 | if (adjval == 0) |
| 1040 | continue; |
| 1041 | if (semundo_adjust(p, &suptr, semid, |
| 1042 | sops[i].sem_num, adjval) != 0) |
| 1043 | panic("semop - can't undo undos" ); |
| 1044 | } |
| 1045 | |
| 1046 | for (i = 0; i < nsops; i++) |
| 1047 | semaptr->_sem_base[sops[i].sem_num].semval -= |
| 1048 | sops[i].sem_op; |
| 1049 | |
| 1050 | SEM_PRINTF(("error = %d from semundo_adjust\n" , error)); |
| 1051 | goto out; |
| 1052 | } /* loop through the sops */ |
| 1053 | } /* if (do_undos) */ |
| 1054 | |
| 1055 | /* We're definitely done - set the sempid's */ |
| 1056 | for (i = 0; i < nsops; i++) { |
| 1057 | sopptr = &sops[i]; |
| 1058 | semptr = &semaptr->_sem_base[sopptr->sem_num]; |
| 1059 | semptr->sempid = p->p_pid; |
| 1060 | } |
| 1061 | |
| 1062 | /* Update sem_otime */ |
| 1063 | semaptr->sem_otime = time_second; |
| 1064 | |
| 1065 | /* Do a wakeup if any semaphore was up'd. */ |
| 1066 | if (do_wakeup) { |
| 1067 | SEM_PRINTF(("semop: doing wakeup\n" )); |
| 1068 | cv_broadcast(&semcv[semid]); |
| 1069 | SEM_PRINTF(("semop: back from wakeup\n" )); |
| 1070 | } |
| 1071 | SEM_PRINTF(("semop: done\n" )); |
| 1072 | *retval = 0; |
| 1073 | |
| 1074 | out: |
| 1075 | mutex_exit(&semlock); |
| 1076 | if (sops != small_sops) |
| 1077 | kmem_free(sops, nsops * sizeof(*sops)); |
| 1078 | return error; |
| 1079 | } |
| 1080 | |
| 1081 | /* |
| 1082 | * Go through the undo structures for this process and apply the |
| 1083 | * adjustments to semaphores. |
| 1084 | */ |
| 1085 | /*ARGSUSED*/ |
| 1086 | void |
| 1087 | semexit(struct proc *p, void *v) |
| 1088 | { |
| 1089 | struct sem_undo *suptr; |
| 1090 | struct sem_undo **supptr; |
| 1091 | |
| 1092 | if ((p->p_flag & PK_SYSVSEM) == 0) |
| 1093 | return; |
| 1094 | |
| 1095 | mutex_enter(&semlock); |
| 1096 | |
| 1097 | /* |
| 1098 | * Go through the chain of undo vectors looking for one |
| 1099 | * associated with this process. |
| 1100 | */ |
| 1101 | |
| 1102 | for (supptr = &semu_list; (suptr = *supptr) != NULL; |
| 1103 | supptr = &suptr->un_next) { |
| 1104 | if (suptr->un_proc == p) |
| 1105 | break; |
| 1106 | } |
| 1107 | |
| 1108 | /* |
| 1109 | * If there is no undo vector, skip to the end. |
| 1110 | */ |
| 1111 | |
| 1112 | if (suptr == NULL) { |
| 1113 | mutex_exit(&semlock); |
| 1114 | return; |
| 1115 | } |
| 1116 | |
| 1117 | /* |
| 1118 | * We now have an undo vector for this process. |
| 1119 | */ |
| 1120 | |
| 1121 | SEM_PRINTF(("proc @%p has undo structure with %d entries\n" , p, |
| 1122 | suptr->un_cnt)); |
| 1123 | |
| 1124 | /* |
| 1125 | * If there are any active undo elements then process them. |
| 1126 | */ |
| 1127 | if (suptr->un_cnt > 0) { |
| 1128 | int ix; |
| 1129 | |
| 1130 | for (ix = 0; ix < suptr->un_cnt; ix++) { |
| 1131 | int semid = suptr->un_ent[ix].un_id; |
| 1132 | int semnum = suptr->un_ent[ix].un_num; |
| 1133 | int adjval = suptr->un_ent[ix].un_adjval; |
| 1134 | struct semid_ds *semaptr; |
| 1135 | |
| 1136 | semaptr = &sema[semid]; |
| 1137 | if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0) |
| 1138 | if (semnum >= semaptr->sem_nsems) |
| 1139 | panic("semexit - semnum out of range" ); |
| 1140 | |
| 1141 | SEM_PRINTF(("semexit: %p id=%d num=%d(adj=%d) ; " |
| 1142 | "sem=%d\n" , |
| 1143 | suptr->un_proc, suptr->un_ent[ix].un_id, |
| 1144 | suptr->un_ent[ix].un_num, |
| 1145 | suptr->un_ent[ix].un_adjval, |
| 1146 | semaptr->_sem_base[semnum].semval)); |
| 1147 | |
| 1148 | if (adjval < 0 && |
| 1149 | semaptr->_sem_base[semnum].semval < -adjval) |
| 1150 | semaptr->_sem_base[semnum].semval = 0; |
| 1151 | else |
| 1152 | semaptr->_sem_base[semnum].semval += adjval; |
| 1153 | |
| 1154 | cv_broadcast(&semcv[semid]); |
| 1155 | SEM_PRINTF(("semexit: back from wakeup\n" )); |
| 1156 | } |
| 1157 | } |
| 1158 | |
| 1159 | /* |
| 1160 | * Deallocate the undo vector. |
| 1161 | */ |
| 1162 | SEM_PRINTF(("removing vector\n" )); |
| 1163 | suptr->un_proc = NULL; |
| 1164 | *supptr = suptr->un_next; |
| 1165 | mutex_exit(&semlock); |
| 1166 | } |
| 1167 | |
| 1168 | /* |
| 1169 | * Sysctl initialization and nodes. |
| 1170 | */ |
| 1171 | |
| 1172 | static int |
| 1173 | sysctl_ipc_semmni(SYSCTLFN_ARGS) |
| 1174 | { |
| 1175 | int newsize, error; |
| 1176 | struct sysctlnode node; |
| 1177 | node = *rnode; |
| 1178 | node.sysctl_data = &newsize; |
| 1179 | |
| 1180 | newsize = seminfo.semmni; |
| 1181 | error = sysctl_lookup(SYSCTLFN_CALL(&node)); |
| 1182 | if (error || newp == NULL) |
| 1183 | return error; |
| 1184 | |
| 1185 | return semrealloc(newsize, seminfo.semmns, seminfo.semmnu); |
| 1186 | } |
| 1187 | |
| 1188 | static int |
| 1189 | sysctl_ipc_semmns(SYSCTLFN_ARGS) |
| 1190 | { |
| 1191 | int newsize, error; |
| 1192 | struct sysctlnode node; |
| 1193 | node = *rnode; |
| 1194 | node.sysctl_data = &newsize; |
| 1195 | |
| 1196 | newsize = seminfo.semmns; |
| 1197 | error = sysctl_lookup(SYSCTLFN_CALL(&node)); |
| 1198 | if (error || newp == NULL) |
| 1199 | return error; |
| 1200 | |
| 1201 | return semrealloc(seminfo.semmni, newsize, seminfo.semmnu); |
| 1202 | } |
| 1203 | |
| 1204 | static int |
| 1205 | sysctl_ipc_semmnu(SYSCTLFN_ARGS) |
| 1206 | { |
| 1207 | int newsize, error; |
| 1208 | struct sysctlnode node; |
| 1209 | node = *rnode; |
| 1210 | node.sysctl_data = &newsize; |
| 1211 | |
| 1212 | newsize = seminfo.semmnu; |
| 1213 | error = sysctl_lookup(SYSCTLFN_CALL(&node)); |
| 1214 | if (error || newp == NULL) |
| 1215 | return error; |
| 1216 | |
| 1217 | return semrealloc(seminfo.semmni, seminfo.semmns, newsize); |
| 1218 | } |
| 1219 | |
| 1220 | SYSCTL_SETUP(sysctl_ipc_sem_setup, "sysctl kern.ipc subtree setup" ) |
| 1221 | { |
| 1222 | const struct sysctlnode *node = NULL; |
| 1223 | |
| 1224 | sysctl_createv(clog, 0, NULL, &node, |
| 1225 | CTLFLAG_PERMANENT, |
| 1226 | CTLTYPE_NODE, "ipc" , |
| 1227 | SYSCTL_DESCR("SysV IPC options" ), |
| 1228 | NULL, 0, NULL, 0, |
| 1229 | CTL_KERN, KERN_SYSVIPC, CTL_EOL); |
| 1230 | |
| 1231 | if (node == NULL) |
| 1232 | return; |
| 1233 | |
| 1234 | sysctl_createv(clog, 0, &node, NULL, |
| 1235 | CTLFLAG_PERMANENT | CTLFLAG_READWRITE, |
| 1236 | CTLTYPE_INT, "semmni" , |
| 1237 | SYSCTL_DESCR("Max number of number of semaphore identifiers" ), |
| 1238 | sysctl_ipc_semmni, 0, &seminfo.semmni, 0, |
| 1239 | CTL_CREATE, CTL_EOL); |
| 1240 | sysctl_createv(clog, 0, &node, NULL, |
| 1241 | CTLFLAG_PERMANENT | CTLFLAG_READWRITE, |
| 1242 | CTLTYPE_INT, "semmns" , |
| 1243 | SYSCTL_DESCR("Max number of number of semaphores in system" ), |
| 1244 | sysctl_ipc_semmns, 0, &seminfo.semmns, 0, |
| 1245 | CTL_CREATE, CTL_EOL); |
| 1246 | sysctl_createv(clog, 0, &node, NULL, |
| 1247 | CTLFLAG_PERMANENT | CTLFLAG_READWRITE, |
| 1248 | CTLTYPE_INT, "semmnu" , |
| 1249 | SYSCTL_DESCR("Max number of undo structures in system" ), |
| 1250 | sysctl_ipc_semmnu, 0, &seminfo.semmnu, 0, |
| 1251 | CTL_CREATE, CTL_EOL); |
| 1252 | } |
| 1253 | |