sysv_shm.c revision 1.50
1 /* $NetBSD: sysv_shm.c,v 1.50 1998/10/21 22:24:29 tron Exp $ */ 2 3 /* 4 * Copyright (c) 1994 Adam Glass and Charles M. 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 M. 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 #define SYSVSHM 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 vaddr_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, shmmap_s->va, size); 167 #else 168 result = vm_map_remove(&vm->vm_map, 169 shmmap_s->va, shmmap_s->va + size); 170 #endif 171 if (result != KERN_SUCCESS) 172 return EINVAL; 173 shmmap_s->shmid = -1; 174 shmseg->shm_dtime = time.tv_sec; 175 if ((--shmseg->shm_nattch <= 0) && 176 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 177 shm_deallocate_segment(shmseg); 178 shm_last_free = segnum; 179 } 180 return 0; 181 } 182 183 int 184 sys_shmdt(p, v, retval) 185 struct proc *p; 186 void *v; 187 register_t *retval; 188 { 189 struct sys_shmdt_args /* { 190 syscallarg(const void *) shmaddr; 191 } */ *uap = v; 192 struct shmmap_state *shmmap_s; 193 int i; 194 195 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 196 if (shmmap_s == NULL) 197 return EINVAL; 198 199 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 200 if (shmmap_s->shmid != -1 && 201 shmmap_s->va == (vaddr_t)SCARG(uap, shmaddr)) 202 break; 203 if (i == shminfo.shmseg) 204 return EINVAL; 205 return shm_delete_mapping(p->p_vmspace, shmmap_s); 206 } 207 208 int 209 sys_shmat(p, v, retval) 210 struct proc *p; 211 void *v; 212 register_t *retval; 213 { 214 struct sys_shmat_args /* { 215 syscallarg(int) shmid; 216 syscallarg(const void *) shmaddr; 217 syscallarg(int) shmflg; 218 } */ *uap = v; 219 int error, i, flags; 220 struct ucred *cred = p->p_ucred; 221 struct shmid_ds *shmseg; 222 struct shmmap_state *shmmap_s = NULL; 223 struct shm_handle *shm_handle; 224 vaddr_t attach_va; 225 vm_prot_t prot; 226 vsize_t size; 227 int rv; 228 229 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 230 if (shmmap_s == NULL) { 231 size = shminfo.shmseg * sizeof(struct shmmap_state); 232 shmmap_s = malloc(size, M_SHM, M_WAITOK); 233 for (i = 0; i < shminfo.shmseg; i++) 234 shmmap_s[i].shmid = -1; 235 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 236 } 237 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 238 if (shmseg == NULL) 239 return EINVAL; 240 error = ipcperm(cred, &shmseg->shm_perm, 241 (SCARG(uap, shmflg) & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 242 if (error) 243 return error; 244 for (i = 0; i < shminfo.shmseg; i++) { 245 if (shmmap_s->shmid == -1) 246 break; 247 shmmap_s++; 248 } 249 if (i >= shminfo.shmseg) 250 return EMFILE; 251 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 252 prot = VM_PROT_READ; 253 if ((SCARG(uap, shmflg) & SHM_RDONLY) == 0) 254 prot |= VM_PROT_WRITE; 255 flags = MAP_ANON | MAP_SHARED; 256 if (SCARG(uap, shmaddr)) { 257 flags |= MAP_FIXED; 258 if (SCARG(uap, shmflg) & SHM_RND) 259 attach_va = 260 (vaddr_t)SCARG(uap, shmaddr) & ~(SHMLBA-1); 261 else if (((vaddr_t)SCARG(uap, shmaddr) & (SHMLBA-1)) == 0) 262 attach_va = (vaddr_t)SCARG(uap, shmaddr); 263 else 264 return EINVAL; 265 } else { 266 /* This is just a hint to vm_mmap() about where to put it. */ 267 attach_va = 268 round_page(p->p_vmspace->vm_taddr + MAXTSIZ + MAXDSIZ); 269 } 270 shm_handle = shmseg->shm_internal; 271 #ifdef UVM 272 uao_reference(shm_handle->shm_object); 273 rv = uvm_map(&p->p_vmspace->vm_map, &attach_va, size, 274 shm_handle->shm_object, 0, 275 UVM_MAPFLAG(prot, prot, UVM_INH_SHARE, 276 UVM_ADV_RANDOM, 0)); 277 if (rv != KERN_SUCCESS) { 278 return ENOMEM; 279 } 280 #else 281 vm_object_reference(shm_handle->shm_object); 282 rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object, 283 0, &attach_va, size, (flags & MAP_FIXED)?0:1); 284 if (rv != KERN_SUCCESS) { 285 return ENOMEM; 286 } 287 vm_map_protect(&p->p_vmspace->vm_map, attach_va, attach_va + size, 288 prot, 0); 289 vm_map_inherit(&p->p_vmspace->vm_map, 290 attach_va, attach_va + size, VM_INHERIT_SHARE); 291 #endif 292 293 shmmap_s->va = attach_va; 294 shmmap_s->shmid = SCARG(uap, shmid); 295 shmseg->shm_lpid = p->p_pid; 296 shmseg->shm_atime = time.tv_sec; 297 shmseg->shm_nattch++; 298 *retval = attach_va; 299 return 0; 300 } 301 302 int 303 sys_shmctl(p, v, retval) 304 struct proc *p; 305 void *v; 306 register_t *retval; 307 { 308 struct sys_shmctl_args /* { 309 syscallarg(int) shmid; 310 syscallarg(int) cmd; 311 syscallarg(struct shmid_ds *) buf; 312 } */ *uap = v; 313 int error; 314 struct ucred *cred = p->p_ucred; 315 struct shmid_ds inbuf; 316 struct shmid_ds *shmseg; 317 318 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 319 if (shmseg == NULL) 320 return EINVAL; 321 switch (SCARG(uap, cmd)) { 322 case IPC_STAT: 323 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) != 0) 324 return error; 325 error = copyout((caddr_t)shmseg, SCARG(uap, buf), 326 sizeof(inbuf)); 327 if (error) 328 return error; 329 break; 330 case IPC_SET: 331 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 332 return error; 333 error = copyin(SCARG(uap, buf), (caddr_t)&inbuf, 334 sizeof(inbuf)); 335 if (error) 336 return error; 337 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 338 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 339 shmseg->shm_perm.mode = 340 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 341 (inbuf.shm_perm.mode & ACCESSPERMS); 342 shmseg->shm_ctime = time.tv_sec; 343 break; 344 case IPC_RMID: 345 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 346 return error; 347 shmseg->shm_perm.key = IPC_PRIVATE; 348 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 349 if (shmseg->shm_nattch <= 0) { 350 shm_deallocate_segment(shmseg); 351 shm_last_free = IPCID_TO_IX(SCARG(uap, shmid)); 352 } 353 break; 354 case SHM_LOCK: 355 case SHM_UNLOCK: 356 default: 357 return EINVAL; 358 } 359 return 0; 360 } 361 362 static int 363 shmget_existing(p, uap, mode, segnum, retval) 364 struct proc *p; 365 struct sys_shmget_args /* { 366 syscallarg(key_t) key; 367 syscallarg(size_t) size; 368 syscallarg(int) shmflg; 369 } */ *uap; 370 int mode; 371 int segnum; 372 register_t *retval; 373 { 374 struct shmid_ds *shmseg; 375 struct ucred *cred = p->p_ucred; 376 int error; 377 378 shmseg = &shmsegs[segnum]; 379 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 380 /* 381 * This segment is in the process of being allocated. Wait 382 * until it's done, and look the key up again (in case the 383 * allocation failed or it was freed). 384 */ 385 shmseg->shm_perm.mode |= SHMSEG_WANTED; 386 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 387 if (error) 388 return error; 389 return EAGAIN; 390 } 391 if ((error = ipcperm(cred, &shmseg->shm_perm, mode)) != 0) 392 return error; 393 if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz) 394 return EINVAL; 395 if ((SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL)) == 396 (IPC_CREAT | IPC_EXCL)) 397 return EEXIST; 398 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 399 return 0; 400 } 401 402 static int 403 shmget_allocate_segment(p, uap, mode, retval) 404 struct proc *p; 405 struct sys_shmget_args /* { 406 syscallarg(key_t) key; 407 syscallarg(size_t) size; 408 syscallarg(int) shmflg; 409 } */ *uap; 410 int mode; 411 register_t *retval; 412 { 413 int i, segnum, shmid, size; 414 struct ucred *cred = p->p_ucred; 415 struct shmid_ds *shmseg; 416 struct shm_handle *shm_handle; 417 #ifndef UVM 418 vm_pager_t pager; 419 #endif 420 int error = 0; 421 422 if (SCARG(uap, size) < shminfo.shmmin || 423 SCARG(uap, size) > shminfo.shmmax) 424 return EINVAL; 425 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 426 return ENOSPC; 427 size = (SCARG(uap, size) + CLOFSET) & ~CLOFSET; 428 if (shm_committed + btoc(size) > shminfo.shmall) 429 return ENOMEM; 430 if (shm_last_free < 0) { 431 for (i = 0; i < shminfo.shmmni; i++) 432 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 433 break; 434 if (i == shminfo.shmmni) 435 panic("shmseg free count inconsistent"); 436 segnum = i; 437 } else { 438 segnum = shm_last_free; 439 shm_last_free = -1; 440 } 441 shmseg = &shmsegs[segnum]; 442 /* 443 * In case we sleep in malloc(), mark the segment present but deleted 444 * so that noone else tries to create the same key. 445 */ 446 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 447 shmseg->shm_perm.key = SCARG(uap, key); 448 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 449 shm_handle = (struct shm_handle *) 450 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 451 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 452 453 454 #ifdef UVM 455 shm_handle->shm_object = uao_create(size, 0); 456 #else 457 shm_handle->shm_object = vm_object_allocate(size); 458 if (shm_handle->shm_object == NULL) { 459 /* XXX cannot happen */ 460 error = ENOMEM; 461 goto out; 462 } 463 /* 464 * We make sure that we have allocated a pager before we need 465 * to. 466 */ 467 pager = vm_pager_allocate(PG_DFLT, 0, size, VM_PROT_DEFAULT, 0); 468 if (pager == NULL) { 469 error = ENOMEM; 470 goto out; 471 } 472 vm_object_setpager(shm_handle->shm_object, pager, 0, 0); 473 #endif 474 475 shmseg->shm_internal = shm_handle; 476 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 477 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 478 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 479 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 480 shmseg->shm_segsz = SCARG(uap, size); 481 shmseg->shm_cpid = p->p_pid; 482 shmseg->shm_lpid = shmseg->shm_nattch = 0; 483 shmseg->shm_atime = shmseg->shm_dtime = 0; 484 shmseg->shm_ctime = time.tv_sec; 485 shm_committed += btoc(size); 486 shm_nused++; 487 488 #ifndef UVM 489 out: 490 if (error) { 491 if (shm_handle->shm_object != NULL) 492 vm_object_deallocate(shm_handle->shm_object); 493 free(shm_handle, M_SHM); 494 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) 495 | SHMSEG_FREE; 496 } else 497 #endif 498 *retval = shmid; 499 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 500 /* 501 * Somebody else wanted this key while we were asleep. Wake 502 * them up now. 503 */ 504 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 505 wakeup((caddr_t)shmseg); 506 } 507 return error; 508 } 509 510 int 511 sys_shmget(p, v, retval) 512 struct proc *p; 513 void *v; 514 register_t *retval; 515 { 516 struct sys_shmget_args /* { 517 syscallarg(key_t) key; 518 syscallarg(int) size; 519 syscallarg(int) shmflg; 520 } */ *uap = v; 521 int segnum, mode, error; 522 523 mode = SCARG(uap, shmflg) & ACCESSPERMS; 524 if (SCARG(uap, key) != IPC_PRIVATE) { 525 again: 526 segnum = shm_find_segment_by_key(SCARG(uap, key)); 527 if (segnum >= 0) { 528 error = shmget_existing(p, uap, mode, segnum, retval); 529 if (error == EAGAIN) 530 goto again; 531 return error; 532 } 533 if ((SCARG(uap, shmflg) & IPC_CREAT) == 0) 534 return ENOENT; 535 } 536 return shmget_allocate_segment(p, uap, mode, retval); 537 } 538 539 void 540 shmfork(vm1, vm2) 541 struct vmspace *vm1, *vm2; 542 { 543 struct shmmap_state *shmmap_s; 544 size_t size; 545 int i; 546 547 if (vm1->vm_shm == NULL) { 548 vm2->vm_shm = NULL; 549 return; 550 } 551 552 size = shminfo.shmseg * sizeof(struct shmmap_state); 553 shmmap_s = malloc(size, M_SHM, M_WAITOK); 554 memcpy(shmmap_s, vm1->vm_shm, size); 555 vm2->vm_shm = (caddr_t)shmmap_s; 556 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 557 if (shmmap_s->shmid != -1) 558 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 559 } 560 561 void 562 shmexit(vm) 563 struct vmspace *vm; 564 { 565 struct shmmap_state *shmmap_s; 566 int i; 567 568 shmmap_s = (struct shmmap_state *)vm->vm_shm; 569 if (shmmap_s == NULL) 570 return; 571 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 572 if (shmmap_s->shmid != -1) 573 shm_delete_mapping(vm, shmmap_s); 574 free(vm->vm_shm, M_SHM); 575 vm->vm_shm = NULL; 576 } 577 578 void 579 shminit() 580 { 581 int i; 582 583 shminfo.shmmax *= NBPG; 584 585 for (i = 0; i < shminfo.shmmni; i++) { 586 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 587 shmsegs[i].shm_perm.seq = 0; 588 } 589 shm_last_free = 0; 590 shm_nused = 0; 591 shm_committed = 0; 592 } 593
Indexes created Wed Sep 24 05:09:52 GMT 2025