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 <vm/vm.h> 47 #include <vm/vm_param.h> 48 #include <sys/lock.h> 49 #include <vm/pmap.h> 50 #include <vm/vm_object.h> 51 #include <vm/vm_map.h> 52 #include <vm/vm_page.h> 53 #include <vm/vm_pager.h> 54 55 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments"); 56 57 static int shmget_allocate_segment (struct proc *p, struct shmget_args *uap, int mode); 58 static int shmget_existing (struct proc *p, struct shmget_args *uap, int mode, int segnum); 59 60 #define SHMSEG_FREE 0x0200 61 #define SHMSEG_REMOVED 0x0400 62 #define SHMSEG_ALLOCATED 0x0800 63 #define SHMSEG_WANTED 0x1000 64 65 static int shm_last_free, shm_committed, shmalloced; 66 int shm_nused; 67 static struct shmid_ds *shmsegs; 68 static struct lwkt_token shm_token = LWKT_TOKEN_INITIALIZER(shm_token); 69 70 struct shm_handle { 71 /* vm_offset_t kva; */ 72 vm_object_t shm_object; 73 }; 74 75 struct shmmap_state { 76 vm_offset_t va; 77 int shmid; 78 }; 79 80 static void shm_deallocate_segment (struct shmid_ds *); 81 static int shm_find_segment_by_key (key_t); 82 static struct shmid_ds *shm_find_segment_by_shmid (int); 83 static int shm_delete_mapping (struct vmspace *vm, struct shmmap_state *); 84 static void shmrealloc (void); 85 static void shminit (void *); 86 87 /* 88 * Tuneable values 89 */ 90 #ifndef SHMMIN 91 #define SHMMIN 1 92 #endif 93 #ifndef SHMMNI 94 #define SHMMNI 512 95 #endif 96 #ifndef SHMSEG 97 #define SHMSEG 1024 98 #endif 99 100 struct shminfo shminfo = { 101 0, 102 SHMMIN, 103 SHMMNI, 104 SHMSEG, 105 0 106 }; 107 108 /* 109 * allow-removed Allow a shared memory segment to be attached by its shmid 110 * even after it has been deleted, as long as it was still 111 * being referenced by someone. This is a trick used by 112 * chrome and other applications to avoid leaving shm 113 * segments hanging around after the application is killed 114 * or seg-faults unexpectedly. 115 * 116 * use-phys Shared memory segments are to use physical memory by 117 * default, which allows the kernel to optimize (remove) 118 * pv_entry management structures for the related PTEs and 119 * prevents paging. This has distinctly different and 120 * usually desireable characteristics verses mmap()ing 121 * anonymous memory. 122 */ 123 static int shm_allow_removed = 1; 124 static int shm_use_phys = 1; 125 126 TUNABLE_LONG("kern.ipc.shmmin", &shminfo.shmmin); 127 TUNABLE_LONG("kern.ipc.shmmni", &shminfo.shmmni); 128 TUNABLE_LONG("kern.ipc.shmseg", &shminfo.shmseg); 129 TUNABLE_LONG("kern.ipc.shmmaxpgs", &shminfo.shmall); 130 TUNABLE_INT("kern.ipc.shm_use_phys", &shm_use_phys); 131 132 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, 133 "Max shared memory segment size"); 134 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, 135 "Min shared memory segment size"); 136 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, 137 "Max number of shared memory identifiers"); 138 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0, 139 "Max shared memory segments per process"); 140 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, 141 "Max pages of shared memory"); 142 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0, 143 "Use phys pager allocation instead of swap pager allocation"); 144 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RW, 145 &shm_allow_removed, 0, 146 "Enable/Disable attachment to attached segments marked for removal"); 147 148 static int 149 shm_find_segment_by_key(key_t key) 150 { 151 int i; 152 153 for (i = 0; i < shmalloced; i++) { 154 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 155 shmsegs[i].shm_perm.key == key) 156 return i; 157 } 158 return -1; 159 } 160 161 static struct shmid_ds * 162 shm_find_segment_by_shmid(int shmid) 163 { 164 int segnum; 165 struct shmid_ds *shmseg; 166 167 segnum = IPCID_TO_IX(shmid); 168 if (segnum < 0 || segnum >= shmalloced) 169 return NULL; 170 shmseg = &shmsegs[segnum]; 171 if ((shmseg->shm_perm.mode & SHMSEG_ALLOCATED) == 0 || 172 (!shm_allow_removed && 173 (shmseg->shm_perm.mode & SHMSEG_REMOVED) != 0) || 174 shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid)) { 175 return NULL; 176 } 177 return shmseg; 178 } 179 180 static void 181 shm_deallocate_segment(struct shmid_ds *shmseg) 182 { 183 struct shm_handle *shm_handle; 184 size_t size; 185 186 shm_handle = shmseg->shm_internal; 187 vm_object_deallocate(shm_handle->shm_object); 188 kfree((caddr_t)shm_handle, M_SHM); 189 shmseg->shm_internal = NULL; 190 size = round_page(shmseg->shm_segsz); 191 shm_committed -= btoc(size); 192 shm_nused--; 193 shmseg->shm_perm.mode = SHMSEG_FREE; 194 } 195 196 static int 197 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s) 198 { 199 struct shmid_ds *shmseg; 200 int segnum, result; 201 size_t size; 202 203 segnum = IPCID_TO_IX(shmmap_s->shmid); 204 shmseg = &shmsegs[segnum]; 205 size = round_page(shmseg->shm_segsz); 206 result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size); 207 if (result != KERN_SUCCESS) 208 return EINVAL; 209 shmmap_s->shmid = -1; 210 shmseg->shm_dtime = time_second; 211 if ((--shmseg->shm_nattch <= 0) && 212 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 213 shm_deallocate_segment(shmseg); 214 shm_last_free = segnum; 215 } 216 return 0; 217 } 218 219 /* 220 * MPALMOSTSAFE 221 */ 222 int 223 sys_shmdt(struct shmdt_args *uap) 224 { 225 struct thread *td = curthread; 226 struct proc *p = td->td_proc; 227 struct shmmap_state *shmmap_s; 228 long i; 229 int error; 230 231 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 232 return (ENOSYS); 233 234 lwkt_gettoken(&shm_token); 235 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 236 if (shmmap_s == NULL) { 237 error = EINVAL; 238 goto done; 239 } 240 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) { 241 if (shmmap_s->shmid != -1 && 242 shmmap_s->va == (vm_offset_t)uap->shmaddr) 243 break; 244 } 245 if (i == shminfo.shmseg) 246 error = EINVAL; 247 else 248 error = shm_delete_mapping(p->p_vmspace, shmmap_s); 249 done: 250 lwkt_reltoken(&shm_token); 251 252 return (error); 253 } 254 255 /* 256 * MPALMOSTSAFE 257 */ 258 int 259 sys_shmat(struct shmat_args *uap) 260 { 261 struct thread *td = curthread; 262 struct proc *p = td->td_proc; 263 int error, flags; 264 long i; 265 struct shmid_ds *shmseg; 266 struct shmmap_state *shmmap_s = NULL; 267 struct shm_handle *shm_handle; 268 vm_offset_t attach_va; 269 vm_prot_t prot; 270 vm_size_t size; 271 vm_size_t align; 272 int rv; 273 274 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 275 return (ENOSYS); 276 277 lwkt_gettoken(&shm_token); 278 again: 279 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 280 if (shmmap_s == NULL) { 281 size = shminfo.shmseg * sizeof(struct shmmap_state); 282 shmmap_s = kmalloc(size, M_SHM, M_WAITOK); 283 for (i = 0; i < shminfo.shmseg; i++) 284 shmmap_s[i].shmid = -1; 285 if (p->p_vmspace->vm_shm != NULL) { 286 kfree(shmmap_s, M_SHM); 287 goto again; 288 } 289 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 290 } 291 shmseg = shm_find_segment_by_shmid(uap->shmid); 292 if (shmseg == NULL) { 293 error = EINVAL; 294 goto done; 295 } 296 error = ipcperm(p, &shmseg->shm_perm, 297 (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 298 if (error) 299 goto done; 300 for (i = 0; i < shminfo.shmseg; i++) { 301 if (shmmap_s->shmid == -1) 302 break; 303 shmmap_s++; 304 } 305 if (i >= shminfo.shmseg) { 306 error = EMFILE; 307 goto done; 308 } 309 size = round_page(shmseg->shm_segsz); 310 #ifdef VM_PROT_READ_IS_EXEC 311 prot = VM_PROT_READ | VM_PROT_EXECUTE; 312 #else 313 prot = VM_PROT_READ; 314 #endif 315 if ((uap->shmflg & SHM_RDONLY) == 0) 316 prot |= VM_PROT_WRITE; 317 flags = MAP_ANON | MAP_SHARED; 318 if (uap->shmaddr) { 319 flags |= MAP_FIXED; 320 if (uap->shmflg & SHM_RND) { 321 attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1); 322 } else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) { 323 attach_va = (vm_offset_t)uap->shmaddr; 324 } else { 325 error = EINVAL; 326 goto done; 327 } 328 } else { 329 /* 330 * This is just a hint to vm_map_find() about where to put it. 331 */ 332 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + 333 maxtsiz + maxdsiz); 334 } 335 336 /* 337 * Handle alignment. For large memory maps it is possible 338 * that the MMU can optimize the page table so align anything 339 * that is a multiple of SEG_SIZE to SEG_SIZE. 340 */ 341 if ((flags & MAP_FIXED) == 0 && (size & SEG_MASK) == 0) 342 align = SEG_SIZE; 343 else 344 align = PAGE_SIZE; 345 346 shm_handle = shmseg->shm_internal; 347 vm_object_hold(shm_handle->shm_object); 348 vm_object_chain_wait(shm_handle->shm_object, 0); 349 vm_object_reference_locked(shm_handle->shm_object); 350 rv = vm_map_find(&p->p_vmspace->vm_map, 351 shm_handle->shm_object, NULL, 352 0, &attach_va, size, 353 align, 354 ((flags & MAP_FIXED) ? 0 : 1), 355 VM_MAPTYPE_NORMAL, VM_SUBSYS_SHMEM, 356 prot, prot, 0); 357 vm_object_drop(shm_handle->shm_object); 358 if (rv != KERN_SUCCESS) { 359 vm_object_deallocate(shm_handle->shm_object); 360 error = ENOMEM; 361 goto done; 362 } 363 vm_map_inherit(&p->p_vmspace->vm_map, 364 attach_va, attach_va + size, VM_INHERIT_SHARE); 365 366 KKASSERT(shmmap_s->shmid == -1); 367 shmmap_s->va = attach_va; 368 shmmap_s->shmid = uap->shmid; 369 shmseg->shm_lpid = p->p_pid; 370 shmseg->shm_atime = time_second; 371 shmseg->shm_nattch++; 372 uap->sysmsg_resultp = (void *)attach_va; 373 error = 0; 374 done: 375 lwkt_reltoken(&shm_token); 376 377 return error; 378 } 379 380 /* 381 * MPALMOSTSAFE 382 */ 383 int 384 sys_shmctl(struct shmctl_args *uap) 385 { 386 struct thread *td = curthread; 387 struct proc *p = td->td_proc; 388 int error; 389 struct shmid_ds inbuf; 390 struct shmid_ds *shmseg; 391 392 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 393 return (ENOSYS); 394 395 lwkt_gettoken(&shm_token); 396 shmseg = shm_find_segment_by_shmid(uap->shmid); 397 if (shmseg == NULL) { 398 error = EINVAL; 399 goto done; 400 } 401 402 switch (uap->cmd) { 403 case IPC_STAT: 404 error = ipcperm(p, &shmseg->shm_perm, IPC_R); 405 if (error == 0) 406 error = copyout(shmseg, uap->buf, sizeof(inbuf)); 407 break; 408 case IPC_SET: 409 error = ipcperm(p, &shmseg->shm_perm, IPC_M); 410 if (error == 0) 411 error = copyin(uap->buf, &inbuf, sizeof(inbuf)); 412 if (error == 0) { 413 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 414 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 415 shmseg->shm_perm.mode = 416 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 417 (inbuf.shm_perm.mode & ACCESSPERMS); 418 shmseg->shm_ctime = time_second; 419 } 420 break; 421 case IPC_RMID: 422 error = ipcperm(p, &shmseg->shm_perm, IPC_M); 423 if (error == 0) { 424 shmseg->shm_perm.key = IPC_PRIVATE; 425 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 426 if (shmseg->shm_nattch <= 0) { 427 shm_deallocate_segment(shmseg); 428 shm_last_free = IPCID_TO_IX(uap->shmid); 429 } 430 } 431 break; 432 #if 0 433 case SHM_LOCK: 434 case SHM_UNLOCK: 435 #endif 436 default: 437 error = EINVAL; 438 break; 439 } 440 done: 441 lwkt_reltoken(&shm_token); 442 443 return error; 444 } 445 446 static int 447 shmget_existing(struct proc *p, struct shmget_args *uap, int mode, int segnum) 448 { 449 struct shmid_ds *shmseg; 450 int error; 451 452 shmseg = &shmsegs[segnum]; 453 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 454 /* 455 * This segment is in the process of being allocated. Wait 456 * until it's done, and look the key up again (in case the 457 * allocation failed or it was freed). 458 */ 459 shmseg->shm_perm.mode |= SHMSEG_WANTED; 460 error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0); 461 if (error) 462 return error; 463 return EAGAIN; 464 } 465 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) 466 return EEXIST; 467 error = ipcperm(p, &shmseg->shm_perm, mode); 468 if (error) 469 return error; 470 if (uap->size && uap->size > shmseg->shm_segsz) 471 return EINVAL; 472 uap->sysmsg_result = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 473 return 0; 474 } 475 476 static int 477 shmget_allocate_segment(struct proc *p, struct shmget_args *uap, int mode) 478 { 479 int i, segnum, shmid; 480 size_t size; 481 struct ucred *cred = p->p_ucred; 482 struct shmid_ds *shmseg; 483 struct shm_handle *shm_handle; 484 485 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 486 return EINVAL; 487 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 488 return ENOSPC; 489 size = round_page(uap->size); 490 if (shm_committed + btoc(size) > shminfo.shmall) 491 return ENOMEM; 492 if (shm_last_free < 0) { 493 shmrealloc(); /* maybe expand the shmsegs[] array */ 494 for (i = 0; i < shmalloced; i++) { 495 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 496 break; 497 } 498 if (i == shmalloced) 499 return ENOSPC; 500 segnum = i; 501 } else { 502 segnum = shm_last_free; 503 shm_last_free = -1; 504 } 505 shmseg = &shmsegs[segnum]; 506 /* 507 * In case we sleep in malloc(), mark the segment present but deleted 508 * so that noone else tries to create the same key. 509 */ 510 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 511 shmseg->shm_perm.key = uap->key; 512 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 513 shm_handle = kmalloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 514 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 515 516 /* 517 * We make sure that we have allocated a pager before we need 518 * to. 519 */ 520 if (shm_use_phys) { 521 shm_handle->shm_object = 522 phys_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0); 523 } else { 524 shm_handle->shm_object = 525 swap_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0); 526 } 527 vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING); 528 vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT); 529 530 shmseg->shm_internal = shm_handle; 531 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 532 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 533 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 534 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 535 shmseg->shm_segsz = uap->size; 536 shmseg->shm_cpid = p->p_pid; 537 shmseg->shm_lpid = shmseg->shm_nattch = 0; 538 shmseg->shm_atime = shmseg->shm_dtime = 0; 539 shmseg->shm_ctime = time_second; 540 shm_committed += btoc(size); 541 shm_nused++; 542 543 /* 544 * If a physical mapping is desired and we have a ton of free pages 545 * we pre-allocate the pages here in order to avoid on-the-fly 546 * allocation later. This has a big effect on database warm-up 547 * times since DFly supports concurrent page faults coming from the 548 * same VM object for pages which already exist. 549 * 550 * This can hang the kernel for a while so only do it if shm_use_phys 551 * is set to 2 or higher. 552 */ 553 if (shm_use_phys > 1) { 554 vm_pindex_t pi, pmax; 555 vm_page_t m; 556 557 pmax = round_page(shmseg->shm_segsz) >> PAGE_SHIFT; 558 vm_object_hold(shm_handle->shm_object); 559 if (pmax > vmstats.v_free_count) 560 pmax = vmstats.v_free_count; 561 for (pi = 0; pi < pmax; ++pi) { 562 m = vm_page_grab(shm_handle->shm_object, pi, 563 VM_ALLOC_SYSTEM | VM_ALLOC_NULL_OK | 564 VM_ALLOC_ZERO); 565 if (m == NULL) 566 break; 567 vm_pager_get_page(shm_handle->shm_object, &m, 1); 568 vm_page_activate(m); 569 vm_page_wakeup(m); 570 lwkt_yield(); 571 } 572 vm_object_drop(shm_handle->shm_object); 573 } 574 575 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 576 /* 577 * Somebody else wanted this key while we were asleep. Wake 578 * them up now. 579 */ 580 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 581 wakeup((caddr_t)shmseg); 582 } 583 uap->sysmsg_result = shmid; 584 return 0; 585 } 586 587 /* 588 * MPALMOSTSAFE 589 */ 590 int 591 sys_shmget(struct shmget_args *uap) 592 { 593 struct thread *td = curthread; 594 struct proc *p = td->td_proc; 595 int segnum, mode, error; 596 597 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 598 return (ENOSYS); 599 600 mode = uap->shmflg & ACCESSPERMS; 601 602 lwkt_gettoken(&shm_token); 603 604 if (uap->key != IPC_PRIVATE) { 605 again: 606 segnum = shm_find_segment_by_key(uap->key); 607 if (segnum >= 0) { 608 error = shmget_existing(p, uap, mode, segnum); 609 if (error == EAGAIN) 610 goto again; 611 goto done; 612 } 613 if ((uap->shmflg & IPC_CREAT) == 0) { 614 error = ENOENT; 615 goto done; 616 } 617 } 618 error = shmget_allocate_segment(p, uap, mode); 619 done: 620 lwkt_reltoken(&shm_token); 621 622 return (error); 623 } 624 625 void 626 shmfork(struct proc *p1, struct proc *p2) 627 { 628 struct shmmap_state *shmmap_s; 629 size_t size; 630 int i; 631 632 lwkt_gettoken(&shm_token); 633 size = shminfo.shmseg * sizeof(struct shmmap_state); 634 shmmap_s = kmalloc(size, M_SHM, M_WAITOK); 635 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size); 636 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s; 637 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) { 638 if (shmmap_s->shmid != -1) 639 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 640 } 641 lwkt_reltoken(&shm_token); 642 } 643 644 void 645 shmexit(struct vmspace *vm) 646 { 647 struct shmmap_state *base, *shm; 648 int i; 649 650 if ((base = (struct shmmap_state *)vm->vm_shm) != NULL) { 651 vm->vm_shm = NULL; 652 lwkt_gettoken(&shm_token); 653 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) { 654 if (shm->shmid != -1) 655 shm_delete_mapping(vm, shm); 656 } 657 kfree(base, M_SHM); 658 lwkt_reltoken(&shm_token); 659 } 660 } 661 662 static void 663 shmrealloc(void) 664 { 665 int i; 666 struct shmid_ds *newsegs; 667 668 if (shmalloced >= shminfo.shmmni) 669 return; 670 671 newsegs = kmalloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); 672 for (i = 0; i < shmalloced; i++) 673 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0])); 674 for (; i < shminfo.shmmni; i++) { 675 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 676 shmsegs[i].shm_perm.seq = 0; 677 } 678 kfree(shmsegs, M_SHM); 679 shmsegs = newsegs; 680 shmalloced = shminfo.shmmni; 681 } 682 683 static void 684 shminit(void *dummy) 685 { 686 int i; 687 688 /* 689 * If not overridden by a tunable set the maximum shm to 690 * 2/3 of main memory. 691 */ 692 if (shminfo.shmall == 0) 693 shminfo.shmall = (size_t)vmstats.v_page_count * 2 / 3; 694 695 shminfo.shmmax = shminfo.shmall * PAGE_SIZE; 696 shmalloced = shminfo.shmmni; 697 shmsegs = kmalloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); 698 for (i = 0; i < shmalloced; i++) { 699 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 700 shmsegs[i].shm_perm.seq = 0; 701 } 702 shm_last_free = 0; 703 shm_nused = 0; 704 shm_committed = 0; 705 } 706 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL); 707