sysv_shm.c revision 1.42
1 /* $NetBSD: sysv_shm.c,v 1.42 1998/02/05 07:59:59 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 <sys/types.h> 34 #include <sys/param.h> 35 #include <sys/kernel.h> 36 #include <sys/shm.h> 37 #include <sys/proc.h> 38 #include <sys/uio.h> 39 #include <sys/time.h> 40 #include <sys/malloc.h> 41 #include <sys/mman.h> 42 #include <sys/systm.h> 43 #include <sys/stat.h> 44 45 #include <sys/mount.h> 46 #include <sys/syscallargs.h> 47 48 #include <vm/vm.h> 49 #ifdef UVM 50 #include <uvm/uvm_extern.h> 51 #else 52 #include <vm/vm_map.h> 53 #include <vm/vm_kern.h> 54 #endif 55 56 struct shmid_ds *shm_find_segment_by_shmid __P((int)); 57 58 /* 59 * Provides the following externally accessible functions: 60 * 61 * shminit(void); initialization 62 * shmexit(struct vmspace *) cleanup 63 * shmfork(struct vmspace *, struct vmspace *) fork handling 64 * shmsys(arg1, arg2, arg3, arg4); shm{at,ctl,dt,get}(arg2, arg3, arg4) 65 * 66 * Structures: 67 * shmsegs (an array of 'struct shmid_ds') 68 * per proc array of 'struct shmmap_state' 69 */ 70 71 #define SHMSEG_FREE 0x0200 72 #define SHMSEG_REMOVED 0x0400 73 #define SHMSEG_ALLOCATED 0x0800 74 #define SHMSEG_WANTED 0x1000 75 76 int shm_last_free, shm_nused, shm_committed; 77 78 struct shm_handle { 79 #ifdef UVM 80 struct uvm_object *shm_object; 81 #else 82 vm_object_t shm_object; 83 #endif 84 }; 85 86 struct shmmap_state { 87 vm_offset_t va; 88 int shmid; 89 }; 90 91 static int shm_find_segment_by_key __P((key_t)); 92 static void shm_deallocate_segment __P((struct shmid_ds *)); 93 static int shm_delete_mapping __P((struct vmspace *, struct shmmap_state *)); 94 static int shmget_existing __P((struct proc *, struct sys_shmget_args *, 95 int, int, register_t *)); 96 static int shmget_allocate_segment __P((struct proc *, struct sys_shmget_args *, 97 int, register_t *)); 98 99 static int 100 shm_find_segment_by_key(key) 101 key_t key; 102 { 103 int i; 104 105 for (i = 0; i < shminfo.shmmni; i++) 106 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 107 shmsegs[i].shm_perm.key == key) 108 return i; 109 return -1; 110 } 111 112 struct shmid_ds * 113 shm_find_segment_by_shmid(shmid) 114 int shmid; 115 { 116 int segnum; 117 struct shmid_ds *shmseg; 118 119 segnum = IPCID_TO_IX(shmid); 120 if (segnum < 0 || segnum >= shminfo.shmmni) 121 return NULL; 122 shmseg = &shmsegs[segnum]; 123 if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED)) 124 != SHMSEG_ALLOCATED || 125 shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid)) 126 return NULL; 127 return shmseg; 128 } 129 130 static void 131 shm_deallocate_segment(shmseg) 132 struct shmid_ds *shmseg; 133 { 134 struct shm_handle *shm_handle; 135 size_t size; 136 137 shm_handle = shmseg->shm_internal; 138 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 139 #ifdef UVM 140 uao_detach(shm_handle->shm_object); 141 #else 142 vm_object_deallocate(shm_handle->shm_object); 143 #endif 144 free((caddr_t)shm_handle, M_SHM); 145 shmseg->shm_internal = NULL; 146 shm_committed -= btoc(size); 147 shmseg->shm_perm.mode = SHMSEG_FREE; 148 shm_nused--; 149 } 150 151 static int 152 shm_delete_mapping(vm, shmmap_s) 153 struct vmspace *vm; 154 struct shmmap_state *shmmap_s; 155 { 156 struct shmid_ds *shmseg; 157 int segnum, result; 158 size_t size; 159 160 segnum = IPCID_TO_IX(shmmap_s->shmid); 161 shmseg = &shmsegs[segnum]; 162 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 163 #ifdef UVM 164 result = uvm_deallocate(&vm->vm_map, 165 shmmap_s->va, shmmap_s->va + size); 166 #else 167 result = vm_map_remove(&vm->vm_map, 168 shmmap_s->va, shmmap_s->va + size); 169 #endif 170 if (result != KERN_SUCCESS) 171 return EINVAL; 172 shmmap_s->shmid = -1; 173 shmseg->shm_dtime = time.tv_sec; 174 if ((--shmseg->shm_nattch <= 0) && 175 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 176 shm_deallocate_segment(shmseg); 177 shm_last_free = segnum; 178 } 179 return 0; 180 } 181 182 int 183 sys_shmdt(p, v, retval) 184 struct proc *p; 185 void *v; 186 register_t *retval; 187 { 188 struct sys_shmdt_args /* { 189 syscallarg(void *) shmaddr; 190 } */ *uap = v; 191 struct shmmap_state *shmmap_s; 192 int i; 193 194 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 195 if (shmmap_s == NULL) 196 return EINVAL; 197 198 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 199 if (shmmap_s->shmid != -1 && 200 shmmap_s->va == (vm_offset_t)SCARG(uap, shmaddr)) 201 break; 202 if (i == shminfo.shmseg) 203 return EINVAL; 204 return shm_delete_mapping(p->p_vmspace, shmmap_s); 205 } 206 207 int 208 sys_shmat(p, v, retval) 209 struct proc *p; 210 void *v; 211 register_t *retval; 212 { 213 struct sys_shmat_args /* { 214 syscallarg(int) shmid; 215 syscallarg(void *) shmaddr; 216 syscallarg(int) shmflg; 217 } */ *uap = v; 218 int error, i, flags; 219 struct ucred *cred = p->p_ucred; 220 struct shmid_ds *shmseg; 221 struct shmmap_state *shmmap_s = NULL; 222 struct shm_handle *shm_handle; 223 vm_offset_t attach_va; 224 vm_prot_t prot; 225 vm_size_t size; 226 int rv; 227 228 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 229 if (shmmap_s == NULL) { 230 size = shminfo.shmseg * sizeof(struct shmmap_state); 231 shmmap_s = malloc(size, M_SHM, M_WAITOK); 232 for (i = 0; i < shminfo.shmseg; i++) 233 shmmap_s[i].shmid = -1; 234 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 235 } 236 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 237 if (shmseg == NULL) 238 return EINVAL; 239 error = ipcperm(cred, &shmseg->shm_perm, 240 (SCARG(uap, shmflg) & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 241 if (error) 242 return error; 243 for (i = 0; i < shminfo.shmseg; i++) { 244 if (shmmap_s->shmid == -1) 245 break; 246 shmmap_s++; 247 } 248 if (i >= shminfo.shmseg) 249 return EMFILE; 250 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 251 prot = VM_PROT_READ; 252 if ((SCARG(uap, shmflg) & SHM_RDONLY) == 0) 253 prot |= VM_PROT_WRITE; 254 flags = MAP_ANON | MAP_SHARED; 255 if (SCARG(uap, shmaddr)) { 256 flags |= MAP_FIXED; 257 if (SCARG(uap, shmflg) & SHM_RND) 258 attach_va = 259 (vm_offset_t)SCARG(uap, shmaddr) & ~(SHMLBA-1); 260 else if (((vm_offset_t)SCARG(uap, shmaddr) & (SHMLBA-1)) == 0) 261 attach_va = (vm_offset_t)SCARG(uap, shmaddr); 262 else 263 return EINVAL; 264 } else { 265 /* This is just a hint to vm_mmap() about where to put it. */ 266 attach_va = 267 round_page(p->p_vmspace->vm_taddr + MAXTSIZ + MAXDSIZ); 268 } 269 shm_handle = shmseg->shm_internal; 270 #ifdef UVM 271 uao_reference(shm_handle->shm_object); 272 rv = uvm_map(&p->p_vmspace->vm_map, &attach_va, size, 273 shm_handle->shm_object, 0, 274 UVM_MAPFLAG(prot, prot, UVM_INH_SHARE, 275 UVM_ADV_RANDOM, 0)); 276 if (rv != KERN_SUCCESS) { 277 return ENOMEM; 278 } 279 #else 280 vm_object_reference(shm_handle->shm_object); 281 rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object, 282 0, &attach_va, size, (flags & MAP_FIXED)?0:1); 283 if (rv != KERN_SUCCESS) { 284 return ENOMEM; 285 } 286 vm_map_protect(&p->p_vmspace->vm_map, attach_va, attach_va + size, 287 prot, 0); 288 vm_map_inherit(&p->p_vmspace->vm_map, 289 attach_va, attach_va + size, VM_INHERIT_SHARE); 290 #endif 291 292 shmmap_s->va = attach_va; 293 shmmap_s->shmid = SCARG(uap, shmid); 294 shmseg->shm_lpid = p->p_pid; 295 shmseg->shm_atime = time.tv_sec; 296 shmseg->shm_nattch++; 297 *retval = attach_va; 298 return 0; 299 } 300 301 int 302 sys_shmctl(p, v, retval) 303 struct proc *p; 304 void *v; 305 register_t *retval; 306 { 307 struct sys_shmctl_args /* { 308 syscallarg(int) shmid; 309 syscallarg(int) cmd; 310 syscallarg(struct shmid_ds *) buf; 311 } */ *uap = v; 312 int error; 313 struct ucred *cred = p->p_ucred; 314 struct shmid_ds inbuf; 315 struct shmid_ds *shmseg; 316 317 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 318 if (shmseg == NULL) 319 return EINVAL; 320 switch (SCARG(uap, cmd)) { 321 case IPC_STAT: 322 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) != 0) 323 return error; 324 error = copyout((caddr_t)shmseg, SCARG(uap, buf), 325 sizeof(inbuf)); 326 if (error) 327 return error; 328 break; 329 case IPC_SET: 330 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 331 return error; 332 error = copyin(SCARG(uap, buf), (caddr_t)&inbuf, 333 sizeof(inbuf)); 334 if (error) 335 return error; 336 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 337 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 338 shmseg->shm_perm.mode = 339 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 340 (inbuf.shm_perm.mode & ACCESSPERMS); 341 shmseg->shm_ctime = time.tv_sec; 342 break; 343 case IPC_RMID: 344 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 345 return error; 346 shmseg->shm_perm.key = IPC_PRIVATE; 347 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 348 if (shmseg->shm_nattch <= 0) { 349 shm_deallocate_segment(shmseg); 350 shm_last_free = IPCID_TO_IX(SCARG(uap, shmid)); 351 } 352 break; 353 case SHM_LOCK: 354 case SHM_UNLOCK: 355 default: 356 return EINVAL; 357 } 358 return 0; 359 } 360 361 static int 362 shmget_existing(p, uap, mode, segnum, retval) 363 struct proc *p; 364 struct sys_shmget_args /* { 365 syscallarg(key_t) key; 366 syscallarg(int) size; 367 syscallarg(int) shmflg; 368 } */ *uap; 369 int mode; 370 int segnum; 371 register_t *retval; 372 { 373 struct shmid_ds *shmseg; 374 struct ucred *cred = p->p_ucred; 375 int error; 376 377 shmseg = &shmsegs[segnum]; 378 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 379 /* 380 * This segment is in the process of being allocated. Wait 381 * until it's done, and look the key up again (in case the 382 * allocation failed or it was freed). 383 */ 384 shmseg->shm_perm.mode |= SHMSEG_WANTED; 385 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 386 if (error) 387 return error; 388 return EAGAIN; 389 } 390 if ((error = ipcperm(cred, &shmseg->shm_perm, mode)) != 0) 391 return error; 392 if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz) 393 return EINVAL; 394 if ((SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL)) == 395 (IPC_CREAT | IPC_EXCL)) 396 return EEXIST; 397 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 398 return 0; 399 } 400 401 static int 402 shmget_allocate_segment(p, uap, mode, retval) 403 struct proc *p; 404 struct sys_shmget_args /* { 405 syscallarg(key_t) key; 406 syscallarg(int) size; 407 syscallarg(int) shmflg; 408 } */ *uap; 409 int mode; 410 register_t *retval; 411 { 412 int i, segnum, shmid, size; 413 struct ucred *cred = p->p_ucred; 414 struct shmid_ds *shmseg; 415 struct shm_handle *shm_handle; 416 #ifndef UVM 417 vm_pager_t pager; 418 #endif 419 int error = 0; 420 421 if (SCARG(uap, size) < shminfo.shmmin || 422 SCARG(uap, size) > shminfo.shmmax) 423 return EINVAL; 424 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 425 return ENOSPC; 426 size = (SCARG(uap, size) + CLOFSET) & ~CLOFSET; 427 if (shm_committed + btoc(size) > shminfo.shmall) 428 return ENOMEM; 429 if (shm_last_free < 0) { 430 for (i = 0; i < shminfo.shmmni; i++) 431 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 432 break; 433 if (i == shminfo.shmmni) 434 panic("shmseg free count inconsistent"); 435 segnum = i; 436 } else { 437 segnum = shm_last_free; 438 shm_last_free = -1; 439 } 440 shmseg = &shmsegs[segnum]; 441 /* 442 * In case we sleep in malloc(), mark the segment present but deleted 443 * so that noone else tries to create the same key. 444 */ 445 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 446 shmseg->shm_perm.key = SCARG(uap, key); 447 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 448 shm_handle = (struct shm_handle *) 449 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 450 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 451 452 453 #ifdef UVM 454 shm_handle->shm_object = uao_create(size, 0); 455 #else 456 shm_handle->shm_object = vm_object_allocate(size); 457 if (shm_handle->shm_object == NULL) { 458 /* XXX cannot happen */ 459 error = ENOMEM; 460 goto out; 461 } 462 /* 463 * We make sure that we have allocated a pager before we need 464 * to. 465 */ 466 pager = vm_pager_allocate(PG_DFLT, 0, size, VM_PROT_DEFAULT, 0); 467 if (pager == NULL) { 468 error = ENOMEM; 469 goto out; 470 } 471 vm_object_setpager(shm_handle->shm_object, pager, 0, 0); 472 #endif 473 474 shmseg->shm_internal = shm_handle; 475 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 476 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 477 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 478 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 479 shmseg->shm_segsz = SCARG(uap, size); 480 shmseg->shm_cpid = p->p_pid; 481 shmseg->shm_lpid = shmseg->shm_nattch = 0; 482 shmseg->shm_atime = shmseg->shm_dtime = 0; 483 shmseg->shm_ctime = time.tv_sec; 484 shm_committed += btoc(size); 485 shm_nused++; 486 487 #ifndef UVM 488 out: 489 if (error) { 490 if (shm_handle->shm_object != NULL) 491 vm_object_deallocate(shm_handle->shm_object); 492 free(shm_handle, M_SHM); 493 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) 494 | SHMSEG_FREE; 495 } else 496 #endif 497 *retval = shmid; 498 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 499 /* 500 * Somebody else wanted this key while we were asleep. Wake 501 * them up now. 502 */ 503 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 504 wakeup((caddr_t)shmseg); 505 } 506 return error; 507 } 508 509 int 510 sys_shmget(p, v, retval) 511 struct proc *p; 512 void *v; 513 register_t *retval; 514 { 515 struct sys_shmget_args /* { 516 syscallarg(key_t) key; 517 syscallarg(int) size; 518 syscallarg(int) shmflg; 519 } */ *uap = v; 520 int segnum, mode, error; 521 522 mode = SCARG(uap, shmflg) & ACCESSPERMS; 523 if (SCARG(uap, key) != IPC_PRIVATE) { 524 again: 525 segnum = shm_find_segment_by_key(SCARG(uap, key)); 526 if (segnum >= 0) { 527 error = shmget_existing(p, uap, mode, segnum, retval); 528 if (error == EAGAIN) 529 goto again; 530 return error; 531 } 532 if ((SCARG(uap, shmflg) & IPC_CREAT) == 0) 533 return ENOENT; 534 } 535 return shmget_allocate_segment(p, uap, mode, retval); 536 } 537 538 void 539 shmfork(vm1, vm2) 540 struct vmspace *vm1, *vm2; 541 { 542 struct shmmap_state *shmmap_s; 543 size_t size; 544 int i; 545 546 if (vm1->vm_shm == NULL) { 547 vm2->vm_shm = NULL; 548 return; 549 } 550 551 size = shminfo.shmseg * sizeof(struct shmmap_state); 552 shmmap_s = malloc(size, M_SHM, M_WAITOK); 553 bcopy(vm1->vm_shm, shmmap_s, size); 554 vm2->vm_shm = (caddr_t)shmmap_s; 555 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 556 if (shmmap_s->shmid != -1) 557 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 558 } 559 560 void 561 shmexit(vm) 562 struct vmspace *vm; 563 { 564 struct shmmap_state *shmmap_s; 565 int i; 566 567 shmmap_s = (struct shmmap_state *)vm->vm_shm; 568 if (shmmap_s == NULL) 569 return; 570 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 571 if (shmmap_s->shmid != -1) 572 shm_delete_mapping(vm, shmmap_s); 573 free(vm->vm_shm, M_SHM); 574 vm->vm_shm = NULL; 575 } 576 577 void 578 shminit() 579 { 580 int i; 581 582 shminfo.shmmax *= NBPG; 583 584 for (i = 0; i < shminfo.shmmni; i++) { 585 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 586 shmsegs[i].shm_perm.seq = 0; 587 } 588 shm_last_free = 0; 589 shm_nused = 0; 590 shm_committed = 0; 591 } 592
Indexes created Thu Sep 25 16:09:42 GMT 2025