sysv_shm.c revision 1.43
1 /* $NetBSD: sysv_shm.c,v 1.43 1998/02/10 14:09:49 mrg Exp $ */ 2 3 /* 4 * Copyright (c) 1994 Adam Glass and Charles Hannum. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Adam Glass and Charles 17 * Hannum. 18 * 4. The names of the authors may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #include "opt_uvm.h" 34 35 #include <sys/types.h> 36 #include <sys/param.h> 37 #include <sys/kernel.h> 38 #include <sys/shm.h> 39 #include <sys/proc.h> 40 #include <sys/uio.h> 41 #include <sys/time.h> 42 #include <sys/malloc.h> 43 #include <sys/mman.h> 44 #include <sys/systm.h> 45 #include <sys/stat.h> 46 47 #include <sys/mount.h> 48 #include <sys/syscallargs.h> 49 50 #include <vm/vm.h> 51 #ifdef UVM 52 #include <uvm/uvm_extern.h> 53 #else 54 #include <vm/vm_map.h> 55 #include <vm/vm_kern.h> 56 #endif 57 58 struct shmid_ds *shm_find_segment_by_shmid __P((int)); 59 60 /* 61 * Provides the following externally accessible functions: 62 * 63 * shminit(void); initialization 64 * shmexit(struct vmspace *) cleanup 65 * shmfork(struct vmspace *, struct vmspace *) fork handling 66 * shmsys(arg1, arg2, arg3, arg4); shm{at,ctl,dt,get}(arg2, arg3, arg4) 67 * 68 * Structures: 69 * shmsegs (an array of 'struct shmid_ds') 70 * per proc array of 'struct shmmap_state' 71 */ 72 73 #define SHMSEG_FREE 0x0200 74 #define SHMSEG_REMOVED 0x0400 75 #define SHMSEG_ALLOCATED 0x0800 76 #define SHMSEG_WANTED 0x1000 77 78 int shm_last_free, shm_nused, shm_committed; 79 80 struct shm_handle { 81 #ifdef UVM 82 struct uvm_object *shm_object; 83 #else 84 vm_object_t shm_object; 85 #endif 86 }; 87 88 struct shmmap_state { 89 vm_offset_t va; 90 int shmid; 91 }; 92 93 static int shm_find_segment_by_key __P((key_t)); 94 static void shm_deallocate_segment __P((struct shmid_ds *)); 95 static int shm_delete_mapping __P((struct vmspace *, struct shmmap_state *)); 96 static int shmget_existing __P((struct proc *, struct sys_shmget_args *, 97 int, int, register_t *)); 98 static int shmget_allocate_segment __P((struct proc *, struct sys_shmget_args *, 99 int, register_t *)); 100 101 static int 102 shm_find_segment_by_key(key) 103 key_t key; 104 { 105 int i; 106 107 for (i = 0; i < shminfo.shmmni; i++) 108 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 109 shmsegs[i].shm_perm.key == key) 110 return i; 111 return -1; 112 } 113 114 struct shmid_ds * 115 shm_find_segment_by_shmid(shmid) 116 int shmid; 117 { 118 int segnum; 119 struct shmid_ds *shmseg; 120 121 segnum = IPCID_TO_IX(shmid); 122 if (segnum < 0 || segnum >= shminfo.shmmni) 123 return NULL; 124 shmseg = &shmsegs[segnum]; 125 if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED)) 126 != SHMSEG_ALLOCATED || 127 shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid)) 128 return NULL; 129 return shmseg; 130 } 131 132 static void 133 shm_deallocate_segment(shmseg) 134 struct shmid_ds *shmseg; 135 { 136 struct shm_handle *shm_handle; 137 size_t size; 138 139 shm_handle = shmseg->shm_internal; 140 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 141 #ifdef UVM 142 uao_detach(shm_handle->shm_object); 143 #else 144 vm_object_deallocate(shm_handle->shm_object); 145 #endif 146 free((caddr_t)shm_handle, M_SHM); 147 shmseg->shm_internal = NULL; 148 shm_committed -= btoc(size); 149 shmseg->shm_perm.mode = SHMSEG_FREE; 150 shm_nused--; 151 } 152 153 static int 154 shm_delete_mapping(vm, shmmap_s) 155 struct vmspace *vm; 156 struct shmmap_state *shmmap_s; 157 { 158 struct shmid_ds *shmseg; 159 int segnum, result; 160 size_t size; 161 162 segnum = IPCID_TO_IX(shmmap_s->shmid); 163 shmseg = &shmsegs[segnum]; 164 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 165 #ifdef UVM 166 result = uvm_deallocate(&vm->vm_map, 167 shmmap_s->va, shmmap_s->va + size); 168 #else 169 result = vm_map_remove(&vm->vm_map, 170 shmmap_s->va, shmmap_s->va + size); 171 #endif 172 if (result != KERN_SUCCESS) 173 return EINVAL; 174 shmmap_s->shmid = -1; 175 shmseg->shm_dtime = time.tv_sec; 176 if ((--shmseg->shm_nattch <= 0) && 177 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 178 shm_deallocate_segment(shmseg); 179 shm_last_free = segnum; 180 } 181 return 0; 182 } 183 184 int 185 sys_shmdt(p, v, retval) 186 struct proc *p; 187 void *v; 188 register_t *retval; 189 { 190 struct sys_shmdt_args /* { 191 syscallarg(void *) shmaddr; 192 } */ *uap = v; 193 struct shmmap_state *shmmap_s; 194 int i; 195 196 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 197 if (shmmap_s == NULL) 198 return EINVAL; 199 200 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 201 if (shmmap_s->shmid != -1 && 202 shmmap_s->va == (vm_offset_t)SCARG(uap, shmaddr)) 203 break; 204 if (i == shminfo.shmseg) 205 return EINVAL; 206 return shm_delete_mapping(p->p_vmspace, shmmap_s); 207 } 208 209 int 210 sys_shmat(p, v, retval) 211 struct proc *p; 212 void *v; 213 register_t *retval; 214 { 215 struct sys_shmat_args /* { 216 syscallarg(int) shmid; 217 syscallarg(void *) shmaddr; 218 syscallarg(int) shmflg; 219 } */ *uap = v; 220 int error, i, flags; 221 struct ucred *cred = p->p_ucred; 222 struct shmid_ds *shmseg; 223 struct shmmap_state *shmmap_s = NULL; 224 struct shm_handle *shm_handle; 225 vm_offset_t attach_va; 226 vm_prot_t prot; 227 vm_size_t size; 228 int rv; 229 230 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 231 if (shmmap_s == NULL) { 232 size = shminfo.shmseg * sizeof(struct shmmap_state); 233 shmmap_s = malloc(size, M_SHM, M_WAITOK); 234 for (i = 0; i < shminfo.shmseg; i++) 235 shmmap_s[i].shmid = -1; 236 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 237 } 238 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 239 if (shmseg == NULL) 240 return EINVAL; 241 error = ipcperm(cred, &shmseg->shm_perm, 242 (SCARG(uap, shmflg) & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 243 if (error) 244 return error; 245 for (i = 0; i < shminfo.shmseg; i++) { 246 if (shmmap_s->shmid == -1) 247 break; 248 shmmap_s++; 249 } 250 if (i >= shminfo.shmseg) 251 return EMFILE; 252 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 253 prot = VM_PROT_READ; 254 if ((SCARG(uap, shmflg) & SHM_RDONLY) == 0) 255 prot |= VM_PROT_WRITE; 256 flags = MAP_ANON | MAP_SHARED; 257 if (SCARG(uap, shmaddr)) { 258 flags |= MAP_FIXED; 259 if (SCARG(uap, shmflg) & SHM_RND) 260 attach_va = 261 (vm_offset_t)SCARG(uap, shmaddr) & ~(SHMLBA-1); 262 else if (((vm_offset_t)SCARG(uap, shmaddr) & (SHMLBA-1)) == 0) 263 attach_va = (vm_offset_t)SCARG(uap, shmaddr); 264 else 265 return EINVAL; 266 } else { 267 /* This is just a hint to vm_mmap() about where to put it. */ 268 attach_va = 269 round_page(p->p_vmspace->vm_taddr + MAXTSIZ + MAXDSIZ); 270 } 271 shm_handle = shmseg->shm_internal; 272 #ifdef UVM 273 uao_reference(shm_handle->shm_object); 274 rv = uvm_map(&p->p_vmspace->vm_map, &attach_va, size, 275 shm_handle->shm_object, 0, 276 UVM_MAPFLAG(prot, prot, UVM_INH_SHARE, 277 UVM_ADV_RANDOM, 0)); 278 if (rv != KERN_SUCCESS) { 279 return ENOMEM; 280 } 281 #else 282 vm_object_reference(shm_handle->shm_object); 283 rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object, 284 0, &attach_va, size, (flags & MAP_FIXED)?0:1); 285 if (rv != KERN_SUCCESS) { 286 return ENOMEM; 287 } 288 vm_map_protect(&p->p_vmspace->vm_map, attach_va, attach_va + size, 289 prot, 0); 290 vm_map_inherit(&p->p_vmspace->vm_map, 291 attach_va, attach_va + size, VM_INHERIT_SHARE); 292 #endif 293 294 shmmap_s->va = attach_va; 295 shmmap_s->shmid = SCARG(uap, shmid); 296 shmseg->shm_lpid = p->p_pid; 297 shmseg->shm_atime = time.tv_sec; 298 shmseg->shm_nattch++; 299 *retval = attach_va; 300 return 0; 301 } 302 303 int 304 sys_shmctl(p, v, retval) 305 struct proc *p; 306 void *v; 307 register_t *retval; 308 { 309 struct sys_shmctl_args /* { 310 syscallarg(int) shmid; 311 syscallarg(int) cmd; 312 syscallarg(struct shmid_ds *) buf; 313 } */ *uap = v; 314 int error; 315 struct ucred *cred = p->p_ucred; 316 struct shmid_ds inbuf; 317 struct shmid_ds *shmseg; 318 319 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 320 if (shmseg == NULL) 321 return EINVAL; 322 switch (SCARG(uap, cmd)) { 323 case IPC_STAT: 324 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) != 0) 325 return error; 326 error = copyout((caddr_t)shmseg, SCARG(uap, buf), 327 sizeof(inbuf)); 328 if (error) 329 return error; 330 break; 331 case IPC_SET: 332 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 333 return error; 334 error = copyin(SCARG(uap, buf), (caddr_t)&inbuf, 335 sizeof(inbuf)); 336 if (error) 337 return error; 338 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 339 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 340 shmseg->shm_perm.mode = 341 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 342 (inbuf.shm_perm.mode & ACCESSPERMS); 343 shmseg->shm_ctime = time.tv_sec; 344 break; 345 case IPC_RMID: 346 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 347 return error; 348 shmseg->shm_perm.key = IPC_PRIVATE; 349 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 350 if (shmseg->shm_nattch <= 0) { 351 shm_deallocate_segment(shmseg); 352 shm_last_free = IPCID_TO_IX(SCARG(uap, shmid)); 353 } 354 break; 355 case SHM_LOCK: 356 case SHM_UNLOCK: 357 default: 358 return EINVAL; 359 } 360 return 0; 361 } 362 363 static int 364 shmget_existing(p, uap, mode, segnum, retval) 365 struct proc *p; 366 struct sys_shmget_args /* { 367 syscallarg(key_t) key; 368 syscallarg(int) size; 369 syscallarg(int) shmflg; 370 } */ *uap; 371 int mode; 372 int segnum; 373 register_t *retval; 374 { 375 struct shmid_ds *shmseg; 376 struct ucred *cred = p->p_ucred; 377 int error; 378 379 shmseg = &shmsegs[segnum]; 380 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 381 /* 382 * This segment is in the process of being allocated. Wait 383 * until it's done, and look the key up again (in case the 384 * allocation failed or it was freed). 385 */ 386 shmseg->shm_perm.mode |= SHMSEG_WANTED; 387 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 388 if (error) 389 return error; 390 return EAGAIN; 391 } 392 if ((error = ipcperm(cred, &shmseg->shm_perm, mode)) != 0) 393 return error; 394 if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz) 395 return EINVAL; 396 if ((SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL)) == 397 (IPC_CREAT | IPC_EXCL)) 398 return EEXIST; 399 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 400 return 0; 401 } 402 403 static int 404 shmget_allocate_segment(p, uap, mode, retval) 405 struct proc *p; 406 struct sys_shmget_args /* { 407 syscallarg(key_t) key; 408 syscallarg(int) size; 409 syscallarg(int) shmflg; 410 } */ *uap; 411 int mode; 412 register_t *retval; 413 { 414 int i, segnum, shmid, size; 415 struct ucred *cred = p->p_ucred; 416 struct shmid_ds *shmseg; 417 struct shm_handle *shm_handle; 418 #ifndef UVM 419 vm_pager_t pager; 420 #endif 421 int error = 0; 422 423 if (SCARG(uap, size) < shminfo.shmmin || 424 SCARG(uap, size) > shminfo.shmmax) 425 return EINVAL; 426 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 427 return ENOSPC; 428 size = (SCARG(uap, size) + CLOFSET) & ~CLOFSET; 429 if (shm_committed + btoc(size) > shminfo.shmall) 430 return ENOMEM; 431 if (shm_last_free < 0) { 432 for (i = 0; i < shminfo.shmmni; i++) 433 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 434 break; 435 if (i == shminfo.shmmni) 436 panic("shmseg free count inconsistent"); 437 segnum = i; 438 } else { 439 segnum = shm_last_free; 440 shm_last_free = -1; 441 } 442 shmseg = &shmsegs[segnum]; 443 /* 444 * In case we sleep in malloc(), mark the segment present but deleted 445 * so that noone else tries to create the same key. 446 */ 447 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 448 shmseg->shm_perm.key = SCARG(uap, key); 449 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 450 shm_handle = (struct shm_handle *) 451 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 452 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 453 454 455 #ifdef UVM 456 shm_handle->shm_object = uao_create(size, 0); 457 #else 458 shm_handle->shm_object = vm_object_allocate(size); 459 if (shm_handle->shm_object == NULL) { 460 /* XXX cannot happen */ 461 error = ENOMEM; 462 goto out; 463 } 464 /* 465 * We make sure that we have allocated a pager before we need 466 * to. 467 */ 468 pager = vm_pager_allocate(PG_DFLT, 0, size, VM_PROT_DEFAULT, 0); 469 if (pager == NULL) { 470 error = ENOMEM; 471 goto out; 472 } 473 vm_object_setpager(shm_handle->shm_object, pager, 0, 0); 474 #endif 475 476 shmseg->shm_internal = shm_handle; 477 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 478 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 479 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 480 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 481 shmseg->shm_segsz = SCARG(uap, size); 482 shmseg->shm_cpid = p->p_pid; 483 shmseg->shm_lpid = shmseg->shm_nattch = 0; 484 shmseg->shm_atime = shmseg->shm_dtime = 0; 485 shmseg->shm_ctime = time.tv_sec; 486 shm_committed += btoc(size); 487 shm_nused++; 488 489 #ifndef UVM 490 out: 491 if (error) { 492 if (shm_handle->shm_object != NULL) 493 vm_object_deallocate(shm_handle->shm_object); 494 free(shm_handle, M_SHM); 495 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) 496 | SHMSEG_FREE; 497 } else 498 #endif 499 *retval = shmid; 500 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 501 /* 502 * Somebody else wanted this key while we were asleep. Wake 503 * them up now. 504 */ 505 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 506 wakeup((caddr_t)shmseg); 507 } 508 return error; 509 } 510 511 int 512 sys_shmget(p, v, retval) 513 struct proc *p; 514 void *v; 515 register_t *retval; 516 { 517 struct sys_shmget_args /* { 518 syscallarg(key_t) key; 519 syscallarg(int) size; 520 syscallarg(int) shmflg; 521 } */ *uap = v; 522 int segnum, mode, error; 523 524 mode = SCARG(uap, shmflg) & ACCESSPERMS; 525 if (SCARG(uap, key) != IPC_PRIVATE) { 526 again: 527 segnum = shm_find_segment_by_key(SCARG(uap, key)); 528 if (segnum >= 0) { 529 error = shmget_existing(p, uap, mode, segnum, retval); 530 if (error == EAGAIN) 531 goto again; 532 return error; 533 } 534 if ((SCARG(uap, shmflg) & IPC_CREAT) == 0) 535 return ENOENT; 536 } 537 return shmget_allocate_segment(p, uap, mode, retval); 538 } 539 540 void 541 shmfork(vm1, vm2) 542 struct vmspace *vm1, *vm2; 543 { 544 struct shmmap_state *shmmap_s; 545 size_t size; 546 int i; 547 548 if (vm1->vm_shm == NULL) { 549 vm2->vm_shm = NULL; 550 return; 551 } 552 553 size = shminfo.shmseg * sizeof(struct shmmap_state); 554 shmmap_s = malloc(size, M_SHM, M_WAITOK); 555 bcopy(vm1->vm_shm, shmmap_s, size); 556 vm2->vm_shm = (caddr_t)shmmap_s; 557 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 558 if (shmmap_s->shmid != -1) 559 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 560 } 561 562 void 563 shmexit(vm) 564 struct vmspace *vm; 565 { 566 struct shmmap_state *shmmap_s; 567 int i; 568 569 shmmap_s = (struct shmmap_state *)vm->vm_shm; 570 if (shmmap_s == NULL) 571 return; 572 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 573 if (shmmap_s->shmid != -1) 574 shm_delete_mapping(vm, shmmap_s); 575 free(vm->vm_shm, M_SHM); 576 vm->vm_shm = NULL; 577 } 578 579 void 580 shminit() 581 { 582 int i; 583 584 shminfo.shmmax *= NBPG; 585 586 for (i = 0; i < shminfo.shmmni; i++) { 587 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 588 shmsegs[i].shm_perm.seq = 0; 589 } 590 shm_last_free = 0; 591 shm_nused = 0; 592 shm_committed = 0; 593 } 594
Indexes created Tue Sep 23 22:09:46 GMT 2025