1 /* 2 * Copyright (c) 1994 Adam Glass and Charles Hannum. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. All advertising materials mentioning features or use of this software 13 * must display the following acknowledgement: 14 * This product includes software developed by Adam Glass and Charles 15 * Hannum. 16 * 4. The names of the authors may not be used to endorse or promote products 17 * derived from this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #include "opt_sysvipc.h" 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/sysproto.h> 36 #include <sys/kernel.h> 37 #include <sys/sysctl.h> 38 #include <sys/shm.h> 39 #include <sys/proc.h> 40 #include <sys/malloc.h> 41 #include <sys/mman.h> 42 #include <sys/stat.h> 43 #include <sys/sysent.h> 44 #include <sys/jail.h> 45 46 #include <sys/mplock2.h> 47 48 #include <vm/vm.h> 49 #include <vm/vm_param.h> 50 #include <sys/lock.h> 51 #include <vm/pmap.h> 52 #include <vm/vm_object.h> 53 #include <vm/vm_map.h> 54 #include <vm/vm_page.h> 55 #include <vm/vm_pager.h> 56 57 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments"); 58 59 static int shmget_allocate_segment (struct proc *p, struct shmget_args *uap, int mode); 60 static int shmget_existing (struct proc *p, struct shmget_args *uap, int mode, int segnum); 61 62 #define SHMSEG_FREE 0x0200 63 #define SHMSEG_REMOVED 0x0400 64 #define SHMSEG_ALLOCATED 0x0800 65 #define SHMSEG_WANTED 0x1000 66 67 static int shm_last_free, shm_committed, shmalloced; 68 int shm_nused; 69 static struct shmid_ds *shmsegs; 70 71 struct shm_handle { 72 /* vm_offset_t kva; */ 73 vm_object_t shm_object; 74 }; 75 76 struct shmmap_state { 77 vm_offset_t va; 78 int shmid; 79 }; 80 81 static void shm_deallocate_segment (struct shmid_ds *); 82 static int shm_find_segment_by_key (key_t); 83 static struct shmid_ds *shm_find_segment_by_shmid (int); 84 static int shm_delete_mapping (struct vmspace *vm, struct shmmap_state *); 85 static void shmrealloc (void); 86 static void shminit (void *); 87 88 /* 89 * Tuneable values 90 */ 91 #ifndef SHMMIN 92 #define SHMMIN 1 93 #endif 94 #ifndef SHMMNI 95 #define SHMMNI 512 96 #endif 97 #ifndef SHMSEG 98 #define SHMSEG 1024 99 #endif 100 101 struct shminfo shminfo = { 102 0, 103 SHMMIN, 104 SHMMNI, 105 SHMSEG, 106 0 107 }; 108 109 static int shm_allow_removed; 110 static int shm_use_phys = 1; 111 112 TUNABLE_LONG("kern.ipc.shmmin", &shminfo.shmmin); 113 TUNABLE_LONG("kern.ipc.shmmni", &shminfo.shmmni); 114 TUNABLE_LONG("kern.ipc.shmseg", &shminfo.shmseg); 115 TUNABLE_LONG("kern.ipc.shmmaxpgs", &shminfo.shmall); 116 TUNABLE_INT("kern.ipc.shm_use_phys", &shm_use_phys); 117 118 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, 119 "Max shared memory segment size"); 120 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, 121 "Min shared memory segment size"); 122 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, 123 "Max number of shared memory identifiers"); 124 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0, 125 "Max shared memory segments per process"); 126 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, 127 "Max pages of shared memory"); 128 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0, 129 "Use phys pager allocation instead of swap pager allocation"); 130 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RW, 131 &shm_allow_removed, 0, 132 "Enable/Disable attachment to attached segments marked for removal"); 133 134 static int 135 shm_find_segment_by_key(key_t key) 136 { 137 int i; 138 139 for (i = 0; i < shmalloced; i++) { 140 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 141 shmsegs[i].shm_perm.key == key) 142 return i; 143 } 144 return -1; 145 } 146 147 static struct shmid_ds * 148 shm_find_segment_by_shmid(int shmid) 149 { 150 int segnum; 151 struct shmid_ds *shmseg; 152 153 segnum = IPCID_TO_IX(shmid); 154 if (segnum < 0 || segnum >= shmalloced) 155 return NULL; 156 shmseg = &shmsegs[segnum]; 157 if ((shmseg->shm_perm.mode & SHMSEG_ALLOCATED) == 0 || 158 (!shm_allow_removed && 159 (shmseg->shm_perm.mode & SHMSEG_REMOVED) != 0) || 160 shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid)) { 161 return NULL; 162 } 163 return shmseg; 164 } 165 166 static void 167 shm_deallocate_segment(struct shmid_ds *shmseg) 168 { 169 struct shm_handle *shm_handle; 170 size_t size; 171 172 shm_handle = shmseg->shm_internal; 173 vm_object_deallocate(shm_handle->shm_object); 174 kfree((caddr_t)shm_handle, M_SHM); 175 shmseg->shm_internal = NULL; 176 size = round_page(shmseg->shm_segsz); 177 shm_committed -= btoc(size); 178 shm_nused--; 179 shmseg->shm_perm.mode = SHMSEG_FREE; 180 } 181 182 static int 183 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s) 184 { 185 struct shmid_ds *shmseg; 186 int segnum, result; 187 size_t size; 188 189 segnum = IPCID_TO_IX(shmmap_s->shmid); 190 shmseg = &shmsegs[segnum]; 191 size = round_page(shmseg->shm_segsz); 192 result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size); 193 if (result != KERN_SUCCESS) 194 return EINVAL; 195 shmmap_s->shmid = -1; 196 shmseg->shm_dtime = time_second; 197 if ((--shmseg->shm_nattch <= 0) && 198 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 199 shm_deallocate_segment(shmseg); 200 shm_last_free = segnum; 201 } 202 return 0; 203 } 204 205 /* 206 * MPALMOSTSAFE 207 */ 208 int 209 sys_shmdt(struct shmdt_args *uap) 210 { 211 struct thread *td = curthread; 212 struct proc *p = td->td_proc; 213 struct shmmap_state *shmmap_s; 214 long i; 215 int error; 216 217 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 218 return (ENOSYS); 219 220 get_mplock(); 221 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 222 if (shmmap_s == NULL) { 223 error = EINVAL; 224 goto done; 225 } 226 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) { 227 if (shmmap_s->shmid != -1 && 228 shmmap_s->va == (vm_offset_t)uap->shmaddr) 229 break; 230 } 231 if (i == shminfo.shmseg) 232 error = EINVAL; 233 else 234 error = shm_delete_mapping(p->p_vmspace, shmmap_s); 235 done: 236 rel_mplock(); 237 return (error); 238 } 239 240 /* 241 * MPALMOSTSAFE 242 */ 243 int 244 sys_shmat(struct shmat_args *uap) 245 { 246 struct thread *td = curthread; 247 struct proc *p = td->td_proc; 248 int error, flags; 249 long i; 250 struct shmid_ds *shmseg; 251 struct shmmap_state *shmmap_s = NULL; 252 struct shm_handle *shm_handle; 253 vm_offset_t attach_va; 254 vm_prot_t prot; 255 vm_size_t size; 256 vm_size_t align; 257 int rv; 258 259 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 260 return (ENOSYS); 261 262 get_mplock(); 263 again: 264 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 265 if (shmmap_s == NULL) { 266 size = shminfo.shmseg * sizeof(struct shmmap_state); 267 shmmap_s = kmalloc(size, M_SHM, M_WAITOK); 268 for (i = 0; i < shminfo.shmseg; i++) 269 shmmap_s[i].shmid = -1; 270 if (p->p_vmspace->vm_shm != NULL) { 271 kfree(shmmap_s, M_SHM); 272 goto again; 273 } 274 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 275 } 276 shmseg = shm_find_segment_by_shmid(uap->shmid); 277 if (shmseg == NULL) { 278 error = EINVAL; 279 goto done; 280 } 281 error = ipcperm(p, &shmseg->shm_perm, 282 (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 283 if (error) 284 goto done; 285 for (i = 0; i < shminfo.shmseg; i++) { 286 if (shmmap_s->shmid == -1) 287 break; 288 shmmap_s++; 289 } 290 if (i >= shminfo.shmseg) { 291 error = EMFILE; 292 goto done; 293 } 294 size = round_page(shmseg->shm_segsz); 295 #ifdef VM_PROT_READ_IS_EXEC 296 prot = VM_PROT_READ | VM_PROT_EXECUTE; 297 #else 298 prot = VM_PROT_READ; 299 #endif 300 if ((uap->shmflg & SHM_RDONLY) == 0) 301 prot |= VM_PROT_WRITE; 302 flags = MAP_ANON | MAP_SHARED; 303 if (uap->shmaddr) { 304 flags |= MAP_FIXED; 305 if (uap->shmflg & SHM_RND) { 306 attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1); 307 } else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) { 308 attach_va = (vm_offset_t)uap->shmaddr; 309 } else { 310 error = EINVAL; 311 goto done; 312 } 313 } else { 314 /* 315 * This is just a hint to vm_map_find() about where to put it. 316 */ 317 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + 318 maxtsiz + maxdsiz); 319 } 320 321 /* 322 * Handle alignment. For large memory maps it is possible 323 * that the MMU can optimize the page table so align anything 324 * that is a multiple of SEG_SIZE to SEG_SIZE. 325 */ 326 if ((flags & MAP_FIXED) == 0 && (size & SEG_MASK) == 0) 327 align = SEG_SIZE; 328 else 329 align = PAGE_SIZE; 330 331 shm_handle = shmseg->shm_internal; 332 vm_object_hold(shm_handle->shm_object); 333 vm_object_chain_wait(shm_handle->shm_object, 0); 334 vm_object_reference_locked(shm_handle->shm_object); 335 rv = vm_map_find(&p->p_vmspace->vm_map, 336 shm_handle->shm_object, NULL, 337 0, &attach_va, size, 338 align, 339 ((flags & MAP_FIXED) ? 0 : 1), 340 VM_MAPTYPE_NORMAL, 341 prot, prot, 0); 342 vm_object_drop(shm_handle->shm_object); 343 if (rv != KERN_SUCCESS) { 344 vm_object_deallocate(shm_handle->shm_object); 345 error = ENOMEM; 346 goto done; 347 } 348 vm_map_inherit(&p->p_vmspace->vm_map, 349 attach_va, attach_va + size, VM_INHERIT_SHARE); 350 351 KKASSERT(shmmap_s->shmid == -1); 352 shmmap_s->va = attach_va; 353 shmmap_s->shmid = uap->shmid; 354 shmseg->shm_lpid = p->p_pid; 355 shmseg->shm_atime = time_second; 356 shmseg->shm_nattch++; 357 uap->sysmsg_resultp = (void *)attach_va; 358 error = 0; 359 done: 360 rel_mplock(); 361 return error; 362 } 363 364 /* 365 * MPALMOSTSAFE 366 */ 367 int 368 sys_shmctl(struct shmctl_args *uap) 369 { 370 struct thread *td = curthread; 371 struct proc *p = td->td_proc; 372 int error; 373 struct shmid_ds inbuf; 374 struct shmid_ds *shmseg; 375 376 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 377 return (ENOSYS); 378 379 get_mplock(); 380 shmseg = shm_find_segment_by_shmid(uap->shmid); 381 if (shmseg == NULL) { 382 error = EINVAL; 383 goto done; 384 } 385 386 switch (uap->cmd) { 387 case IPC_STAT: 388 error = ipcperm(p, &shmseg->shm_perm, IPC_R); 389 if (error == 0) 390 error = copyout(shmseg, uap->buf, sizeof(inbuf)); 391 break; 392 case IPC_SET: 393 error = ipcperm(p, &shmseg->shm_perm, IPC_M); 394 if (error == 0) 395 error = copyin(uap->buf, &inbuf, sizeof(inbuf)); 396 if (error == 0) { 397 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 398 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 399 shmseg->shm_perm.mode = 400 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 401 (inbuf.shm_perm.mode & ACCESSPERMS); 402 shmseg->shm_ctime = time_second; 403 } 404 break; 405 case IPC_RMID: 406 error = ipcperm(p, &shmseg->shm_perm, IPC_M); 407 if (error == 0) { 408 shmseg->shm_perm.key = IPC_PRIVATE; 409 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 410 if (shmseg->shm_nattch <= 0) { 411 shm_deallocate_segment(shmseg); 412 shm_last_free = IPCID_TO_IX(uap->shmid); 413 } 414 } 415 break; 416 #if 0 417 case SHM_LOCK: 418 case SHM_UNLOCK: 419 #endif 420 default: 421 error = EINVAL; 422 break; 423 } 424 done: 425 rel_mplock(); 426 return error; 427 } 428 429 static int 430 shmget_existing(struct proc *p, struct shmget_args *uap, int mode, int segnum) 431 { 432 struct shmid_ds *shmseg; 433 int error; 434 435 shmseg = &shmsegs[segnum]; 436 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 437 /* 438 * This segment is in the process of being allocated. Wait 439 * until it's done, and look the key up again (in case the 440 * allocation failed or it was freed). 441 */ 442 shmseg->shm_perm.mode |= SHMSEG_WANTED; 443 error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0); 444 if (error) 445 return error; 446 return EAGAIN; 447 } 448 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) 449 return EEXIST; 450 error = ipcperm(p, &shmseg->shm_perm, mode); 451 if (error) 452 return error; 453 if (uap->size && uap->size > shmseg->shm_segsz) 454 return EINVAL; 455 uap->sysmsg_result = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 456 return 0; 457 } 458 459 static int 460 shmget_allocate_segment(struct proc *p, struct shmget_args *uap, int mode) 461 { 462 int i, segnum, shmid; 463 size_t size; 464 struct ucred *cred = p->p_ucred; 465 struct shmid_ds *shmseg; 466 struct shm_handle *shm_handle; 467 468 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 469 return EINVAL; 470 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 471 return ENOSPC; 472 size = round_page(uap->size); 473 if (shm_committed + btoc(size) > shminfo.shmall) 474 return ENOMEM; 475 if (shm_last_free < 0) { 476 shmrealloc(); /* maybe expand the shmsegs[] array */ 477 for (i = 0; i < shmalloced; i++) { 478 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 479 break; 480 } 481 if (i == shmalloced) 482 return ENOSPC; 483 segnum = i; 484 } else { 485 segnum = shm_last_free; 486 shm_last_free = -1; 487 } 488 shmseg = &shmsegs[segnum]; 489 /* 490 * In case we sleep in malloc(), mark the segment present but deleted 491 * so that noone else tries to create the same key. 492 */ 493 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 494 shmseg->shm_perm.key = uap->key; 495 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 496 shm_handle = kmalloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 497 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 498 499 /* 500 * We make sure that we have allocated a pager before we need 501 * to. 502 */ 503 if (shm_use_phys) { 504 shm_handle->shm_object = 505 phys_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0); 506 } else { 507 shm_handle->shm_object = 508 swap_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0); 509 } 510 vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING); 511 vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT); 512 513 shmseg->shm_internal = shm_handle; 514 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 515 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 516 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 517 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 518 shmseg->shm_segsz = uap->size; 519 shmseg->shm_cpid = p->p_pid; 520 shmseg->shm_lpid = shmseg->shm_nattch = 0; 521 shmseg->shm_atime = shmseg->shm_dtime = 0; 522 shmseg->shm_ctime = time_second; 523 shm_committed += btoc(size); 524 shm_nused++; 525 526 /* 527 * If a physical mapping is desired and we have a ton of free pages 528 * we pre-allocate the pages here in order to avoid on-the-fly 529 * allocation later. This has a big effect on database warm-up 530 * times since DFly supports concurrent page faults coming from the 531 * same VM object for pages which already exist. 532 * 533 * This can hang the kernel for a while so only do it if shm_use_phys 534 * is set to 2 or higher. 535 */ 536 if (shm_use_phys > 1) { 537 vm_pindex_t pi, pmax; 538 vm_page_t m; 539 540 pmax = round_page(shmseg->shm_segsz) >> PAGE_SHIFT; 541 vm_object_hold(shm_handle->shm_object); 542 if (pmax > vmstats.v_free_count) 543 pmax = vmstats.v_free_count; 544 for (pi = 0; pi < pmax; ++pi) { 545 m = vm_page_grab(shm_handle->shm_object, pi, 546 VM_ALLOC_SYSTEM | VM_ALLOC_NULL_OK | 547 VM_ALLOC_ZERO); 548 if (m == NULL) 549 break; 550 vm_pager_get_page(shm_handle->shm_object, &m, 1); 551 vm_page_activate(m); 552 vm_page_wakeup(m); 553 lwkt_yield(); 554 } 555 vm_object_drop(shm_handle->shm_object); 556 } 557 558 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 559 /* 560 * Somebody else wanted this key while we were asleep. Wake 561 * them up now. 562 */ 563 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 564 wakeup((caddr_t)shmseg); 565 } 566 uap->sysmsg_result = shmid; 567 return 0; 568 } 569 570 /* 571 * MPALMOSTSAFE 572 */ 573 int 574 sys_shmget(struct shmget_args *uap) 575 { 576 struct thread *td = curthread; 577 struct proc *p = td->td_proc; 578 int segnum, mode, error; 579 580 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 581 return (ENOSYS); 582 583 mode = uap->shmflg & ACCESSPERMS; 584 get_mplock(); 585 586 if (uap->key != IPC_PRIVATE) { 587 again: 588 segnum = shm_find_segment_by_key(uap->key); 589 if (segnum >= 0) { 590 error = shmget_existing(p, uap, mode, segnum); 591 if (error == EAGAIN) 592 goto again; 593 goto done; 594 } 595 if ((uap->shmflg & IPC_CREAT) == 0) { 596 error = ENOENT; 597 goto done; 598 } 599 } 600 error = shmget_allocate_segment(p, uap, mode); 601 done: 602 rel_mplock(); 603 return (error); 604 } 605 606 void 607 shmfork(struct proc *p1, struct proc *p2) 608 { 609 struct shmmap_state *shmmap_s; 610 size_t size; 611 int i; 612 613 get_mplock(); 614 size = shminfo.shmseg * sizeof(struct shmmap_state); 615 shmmap_s = kmalloc(size, M_SHM, M_WAITOK); 616 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size); 617 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s; 618 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) { 619 if (shmmap_s->shmid != -1) 620 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 621 } 622 rel_mplock(); 623 } 624 625 void 626 shmexit(struct vmspace *vm) 627 { 628 struct shmmap_state *base, *shm; 629 int i; 630 631 if ((base = (struct shmmap_state *)vm->vm_shm) != NULL) { 632 vm->vm_shm = NULL; 633 get_mplock(); 634 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) { 635 if (shm->shmid != -1) 636 shm_delete_mapping(vm, shm); 637 } 638 kfree(base, M_SHM); 639 rel_mplock(); 640 } 641 } 642 643 static void 644 shmrealloc(void) 645 { 646 int i; 647 struct shmid_ds *newsegs; 648 649 if (shmalloced >= shminfo.shmmni) 650 return; 651 652 newsegs = kmalloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); 653 for (i = 0; i < shmalloced; i++) 654 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0])); 655 for (; i < shminfo.shmmni; i++) { 656 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 657 shmsegs[i].shm_perm.seq = 0; 658 } 659 kfree(shmsegs, M_SHM); 660 shmsegs = newsegs; 661 shmalloced = shminfo.shmmni; 662 } 663 664 static void 665 shminit(void *dummy) 666 { 667 int i; 668 669 /* 670 * If not overridden by a tunable set the maximum shm to 671 * 2/3 of main memory. 672 */ 673 if (shminfo.shmall == 0) 674 shminfo.shmall = (size_t)vmstats.v_page_count * 2 / 3; 675 676 shminfo.shmmax = shminfo.shmall * PAGE_SIZE; 677 shmalloced = shminfo.shmmni; 678 shmsegs = kmalloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); 679 for (i = 0; i < shmalloced; i++) { 680 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 681 shmsegs[i].shm_perm.seq = 0; 682 } 683 shm_last_free = 0; 684 shm_nused = 0; 685 shm_committed = 0; 686 } 687 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL); 688