sysv_shm.c revision 1.64.4.2
1 /* $NetBSD: sysv_shm.c,v 1.64.4.2 2004/02/09 13:16:55 tron Exp $ */ 2 3 /*- 4 * Copyright (c) 1999 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /* 41 * Copyright (c) 1994 Adam Glass and Charles M. Hannum. All rights reserved. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. All advertising materials mentioning features or use of this software 52 * must display the following acknowledgement: 53 * This product includes software developed by Adam Glass and Charles M. 54 * Hannum. 55 * 4. The names of the authors may not be used to endorse or promote products 56 * derived from this software without specific prior written permission. 57 * 58 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR 59 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 60 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 61 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, 62 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 63 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 64 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 65 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 66 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 67 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 68 */ 69 70 #include <sys/cdefs.h> 71 __KERNEL_RCSID(0, "$NetBSD: sysv_shm.c,v 1.64.4.2 2004/02/09 13:16:55 tron Exp $"); 72 73 #define SYSVSHM 74 75 #include <sys/param.h> 76 #include <sys/kernel.h> 77 #include <sys/shm.h> 78 #include <sys/malloc.h> 79 #include <sys/mman.h> 80 #include <sys/stat.h> 81 #include <sys/sysctl.h> 82 #include <sys/mount.h> /* XXX for <sys/syscallargs.h> */ 83 #include <sys/syscallargs.h> 84 85 #include <uvm/uvm_extern.h> 86 #include <uvm/uvm_object.h> 87 88 struct shmid_ds *shm_find_segment_by_shmid __P((int, int)); 89 90 /* 91 * Provides the following externally accessible functions: 92 * 93 * shminit(void); initialization 94 * shmexit(struct vmspace *) cleanup 95 * shmfork(struct vmspace *, struct vmspace *) fork handling 96 * 97 * Structures: 98 * shmsegs (an array of 'struct shmid_ds') 99 * per proc array of 'struct shmmap_state' 100 */ 101 102 #define SHMSEG_FREE 0x0200 103 #define SHMSEG_REMOVED 0x0400 104 #define SHMSEG_ALLOCATED 0x0800 105 #define SHMSEG_WANTED 0x1000 106 107 int shm_last_free, shm_nused, shm_committed; 108 struct shmid_ds *shmsegs; 109 110 struct shm_handle { 111 struct uvm_object *shm_object; 112 }; 113 114 struct shmmap_state { 115 vaddr_t va; 116 int shmid; 117 }; 118 119 static int shm_find_segment_by_key __P((key_t)); 120 static void shm_deallocate_segment __P((struct shmid_ds *)); 121 static void shm_delete_mapping __P((struct vmspace *, struct shmmap_state *)); 122 static int shmget_existing __P((struct proc *, struct sys_shmget_args *, 123 int, int, register_t *)); 124 static int shmget_allocate_segment __P((struct proc *, struct sys_shmget_args *, 125 int, register_t *)); 126 127 static int 128 shm_find_segment_by_key(key) 129 key_t key; 130 { 131 int i; 132 133 for (i = 0; i < shminfo.shmmni; i++) 134 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 135 shmsegs[i].shm_perm._key == key) 136 return i; 137 return -1; 138 } 139 140 struct shmid_ds * 141 shm_find_segment_by_shmid(shmid, findremoved) 142 int shmid; 143 int findremoved; 144 { 145 int segnum; 146 struct shmid_ds *shmseg; 147 148 segnum = IPCID_TO_IX(shmid); 149 if (segnum < 0 || segnum >= shminfo.shmmni) 150 return NULL; 151 shmseg = &shmsegs[segnum]; 152 if ((shmseg->shm_perm.mode & SHMSEG_ALLOCATED) == 0) 153 return NULL; 154 if (!findremoved && ((shmseg->shm_perm.mode & SHMSEG_REMOVED) != 0)) 155 return NULL; 156 if (shmseg->shm_perm._seq != IPCID_TO_SEQ(shmid)) 157 return NULL; 158 return shmseg; 159 } 160 161 static void 162 shm_deallocate_segment(shmseg) 163 struct shmid_ds *shmseg; 164 { 165 struct shm_handle *shm_handle = shmseg->_shm_internal; 166 struct uvm_object *uobj = shm_handle->shm_object; 167 size_t size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 168 169 (*uobj->pgops->pgo_detach)(uobj); 170 free((caddr_t)shm_handle, M_SHM); 171 shmseg->_shm_internal = NULL; 172 shm_committed -= btoc(size); 173 shmseg->shm_perm.mode = SHMSEG_FREE; 174 shm_nused--; 175 } 176 177 static void 178 shm_delete_mapping(vm, shmmap_s) 179 struct vmspace *vm; 180 struct shmmap_state *shmmap_s; 181 { 182 struct shmid_ds *shmseg; 183 int segnum; 184 size_t size; 185 186 segnum = IPCID_TO_IX(shmmap_s->shmid); 187 shmseg = &shmsegs[segnum]; 188 size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 189 uvm_deallocate(&vm->vm_map, shmmap_s->va, size); 190 shmmap_s->shmid = -1; 191 shmseg->shm_dtime = time.tv_sec; 192 if ((--shmseg->shm_nattch <= 0) && 193 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 194 shm_deallocate_segment(shmseg); 195 shm_last_free = segnum; 196 } 197 } 198 199 int 200 sys_shmdt(p, v, retval) 201 struct proc *p; 202 void *v; 203 register_t *retval; 204 { 205 struct sys_shmdt_args /* { 206 syscallarg(const void *) shmaddr; 207 } */ *uap = v; 208 struct shmmap_state *shmmap_s; 209 int i; 210 211 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 212 if (shmmap_s == NULL) 213 return EINVAL; 214 215 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 216 if (shmmap_s->shmid != -1 && 217 shmmap_s->va == (vaddr_t)SCARG(uap, shmaddr)) 218 break; 219 if (i == shminfo.shmseg) 220 return EINVAL; 221 shm_delete_mapping(p->p_vmspace, shmmap_s); 222 return 0; 223 } 224 225 int 226 sys_shmat(p, v, retval) 227 struct proc *p; 228 void *v; 229 register_t *retval; 230 { 231 struct sys_shmat_args /* { 232 syscallarg(int) shmid; 233 syscallarg(const void *) shmaddr; 234 syscallarg(int) shmflg; 235 } */ *uap = v; 236 vaddr_t attach_va; 237 int error; 238 239 error = shmat1(p, SCARG(uap, shmid), SCARG(uap, shmaddr), 240 SCARG(uap, shmflg), &attach_va, 0); 241 if (error != 0) 242 return error; 243 retval[0] = attach_va; 244 return 0; 245 } 246 247 int 248 shmat1(p, shmid, shmaddr, shmflg, attachp, findremoved) 249 struct proc *p; 250 int shmid; 251 const void *shmaddr; 252 int shmflg; 253 vaddr_t *attachp; 254 int findremoved; 255 { 256 int error, i, flags; 257 struct ucred *cred = p->p_ucred; 258 struct shmid_ds *shmseg; 259 struct shmmap_state *shmmap_s = NULL; 260 struct uvm_object *uobj; 261 vaddr_t attach_va; 262 vm_prot_t prot; 263 vsize_t size; 264 265 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 266 if (shmmap_s == NULL) { 267 size = shminfo.shmseg * sizeof(struct shmmap_state); 268 shmmap_s = malloc(size, M_SHM, M_WAITOK); 269 for (i = 0; i < shminfo.shmseg; i++) 270 shmmap_s[i].shmid = -1; 271 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 272 } 273 shmseg = shm_find_segment_by_shmid(shmid, findremoved); 274 if (shmseg == NULL) 275 return EINVAL; 276 error = ipcperm(cred, &shmseg->shm_perm, 277 (shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 278 if (error) 279 return error; 280 for (i = 0; i < shminfo.shmseg; i++) { 281 if (shmmap_s->shmid == -1) 282 break; 283 shmmap_s++; 284 } 285 if (i >= shminfo.shmseg) 286 return EMFILE; 287 size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 288 prot = VM_PROT_READ; 289 if ((shmflg & SHM_RDONLY) == 0) 290 prot |= VM_PROT_WRITE; 291 flags = MAP_ANON | MAP_SHARED; 292 if (shmaddr) { 293 flags |= MAP_FIXED; 294 if (shmflg & SHM_RND) 295 attach_va = 296 (vaddr_t)shmaddr & ~(SHMLBA-1); 297 else if (((vaddr_t)shmaddr & (SHMLBA-1)) == 0) 298 attach_va = (vaddr_t)shmaddr; 299 else 300 return EINVAL; 301 } else { 302 /* This is just a hint to vm_mmap() about where to put it. */ 303 attach_va = 304 round_page((vaddr_t)p->p_vmspace->vm_taddr + 305 MAXTSIZ + MAXDSIZ); 306 } 307 uobj = ((struct shm_handle *)shmseg->_shm_internal)->shm_object; 308 (*uobj->pgops->pgo_reference)(uobj); 309 error = uvm_map(&p->p_vmspace->vm_map, &attach_va, size, 310 uobj, 0, 0, 311 UVM_MAPFLAG(prot, prot, UVM_INH_SHARE, UVM_ADV_RANDOM, 0)); 312 if (error) { 313 (*uobj->pgops->pgo_detach)(uobj); 314 return error; 315 } 316 shmmap_s->va = attach_va; 317 shmmap_s->shmid = shmid; 318 shmseg->shm_lpid = p->p_pid; 319 shmseg->shm_atime = time.tv_sec; 320 shmseg->shm_nattch++; 321 *attachp = attach_va; 322 return 0; 323 } 324 325 int 326 sys___shmctl13(p, v, retval) 327 struct proc *p; 328 void *v; 329 register_t *retval; 330 { 331 struct sys___shmctl13_args /* { 332 syscallarg(int) shmid; 333 syscallarg(int) cmd; 334 syscallarg(struct shmid_ds *) buf; 335 } */ *uap = v; 336 struct shmid_ds shmbuf; 337 int cmd, error; 338 339 cmd = SCARG(uap, cmd); 340 341 if (cmd == IPC_SET) { 342 error = copyin(SCARG(uap, buf), &shmbuf, sizeof(shmbuf)); 343 if (error) 344 return (error); 345 } 346 347 error = shmctl1(p, SCARG(uap, shmid), cmd, 348 (cmd == IPC_SET || cmd == IPC_STAT) ? &shmbuf : NULL); 349 350 if (error == 0 && cmd == IPC_STAT) 351 error = copyout(&shmbuf, SCARG(uap, buf), sizeof(shmbuf)); 352 353 return (error); 354 } 355 356 int 357 shmctl1(p, shmid, cmd, shmbuf) 358 struct proc *p; 359 int shmid; 360 int cmd; 361 struct shmid_ds *shmbuf; 362 { 363 struct ucred *cred = p->p_ucred; 364 struct shmid_ds *shmseg; 365 int error = 0; 366 367 shmseg = shm_find_segment_by_shmid(shmid, 0); 368 if (shmseg == NULL) 369 return EINVAL; 370 switch (cmd) { 371 case IPC_STAT: 372 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) != 0) 373 return error; 374 memcpy(shmbuf, shmseg, sizeof(struct shmid_ds)); 375 break; 376 case IPC_SET: 377 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 378 return error; 379 shmseg->shm_perm.uid = shmbuf->shm_perm.uid; 380 shmseg->shm_perm.gid = shmbuf->shm_perm.gid; 381 shmseg->shm_perm.mode = 382 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 383 (shmbuf->shm_perm.mode & ACCESSPERMS); 384 shmseg->shm_ctime = time.tv_sec; 385 break; 386 case IPC_RMID: 387 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 388 return error; 389 shmseg->shm_perm._key = IPC_PRIVATE; 390 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 391 if (shmseg->shm_nattch <= 0) { 392 shm_deallocate_segment(shmseg); 393 shm_last_free = IPCID_TO_IX(shmid); 394 } 395 break; 396 case SHM_LOCK: 397 case SHM_UNLOCK: 398 default: 399 return EINVAL; 400 } 401 return 0; 402 } 403 404 static int 405 shmget_existing(p, uap, mode, segnum, retval) 406 struct proc *p; 407 struct sys_shmget_args /* { 408 syscallarg(key_t) key; 409 syscallarg(size_t) size; 410 syscallarg(int) shmflg; 411 } */ *uap; 412 int mode; 413 int segnum; 414 register_t *retval; 415 { 416 struct shmid_ds *shmseg; 417 struct ucred *cred = p->p_ucred; 418 int error; 419 420 shmseg = &shmsegs[segnum]; 421 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 422 /* 423 * This segment is in the process of being allocated. Wait 424 * until it's done, and look the key up again (in case the 425 * allocation failed or it was freed). 426 */ 427 shmseg->shm_perm.mode |= SHMSEG_WANTED; 428 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 429 if (error) 430 return error; 431 return EAGAIN; 432 } 433 if ((error = ipcperm(cred, &shmseg->shm_perm, mode)) != 0) 434 return error; 435 if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz) 436 return EINVAL; 437 if ((SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL)) == 438 (IPC_CREAT | IPC_EXCL)) 439 return EEXIST; 440 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 441 return 0; 442 } 443 444 static int 445 shmget_allocate_segment(p, uap, mode, retval) 446 struct proc *p; 447 struct sys_shmget_args /* { 448 syscallarg(key_t) key; 449 syscallarg(size_t) size; 450 syscallarg(int) shmflg; 451 } */ *uap; 452 int mode; 453 register_t *retval; 454 { 455 int i, segnum, shmid, size; 456 struct ucred *cred = p->p_ucred; 457 struct shmid_ds *shmseg; 458 struct shm_handle *shm_handle; 459 int error = 0; 460 461 if (SCARG(uap, size) < shminfo.shmmin || 462 SCARG(uap, size) > shminfo.shmmax) 463 return EINVAL; 464 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 465 return ENOSPC; 466 size = (SCARG(uap, size) + PGOFSET) & ~PGOFSET; 467 if (shm_committed + btoc(size) > shminfo.shmall) 468 return ENOMEM; 469 if (shm_last_free < 0) { 470 for (i = 0; i < shminfo.shmmni; i++) 471 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 472 break; 473 if (i == shminfo.shmmni) 474 panic("shmseg free count inconsistent"); 475 segnum = i; 476 } else { 477 segnum = shm_last_free; 478 shm_last_free = -1; 479 } 480 shmseg = &shmsegs[segnum]; 481 /* 482 * In case we sleep in malloc(), mark the segment present but deleted 483 * so that noone else tries to create the same key. 484 */ 485 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 486 shmseg->shm_perm._key = SCARG(uap, key); 487 shmseg->shm_perm._seq = (shmseg->shm_perm._seq + 1) & 0x7fff; 488 shm_handle = (struct shm_handle *) 489 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 490 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 491 492 shm_handle->shm_object = uao_create(size, 0); 493 494 shmseg->_shm_internal = shm_handle; 495 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 496 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 497 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 498 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 499 shmseg->shm_segsz = SCARG(uap, size); 500 shmseg->shm_cpid = p->p_pid; 501 shmseg->shm_lpid = shmseg->shm_nattch = 0; 502 shmseg->shm_atime = shmseg->shm_dtime = 0; 503 shmseg->shm_ctime = time.tv_sec; 504 shm_committed += btoc(size); 505 shm_nused++; 506 507 *retval = shmid; 508 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 509 /* 510 * Somebody else wanted this key while we were asleep. Wake 511 * them up now. 512 */ 513 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 514 wakeup((caddr_t)shmseg); 515 } 516 return error; 517 } 518 519 int 520 sys_shmget(p, v, retval) 521 struct proc *p; 522 void *v; 523 register_t *retval; 524 { 525 struct sys_shmget_args /* { 526 syscallarg(key_t) key; 527 syscallarg(int) size; 528 syscallarg(int) shmflg; 529 } */ *uap = v; 530 int segnum, mode, error; 531 532 mode = SCARG(uap, shmflg) & ACCESSPERMS; 533 if (SCARG(uap, key) != IPC_PRIVATE) { 534 again: 535 segnum = shm_find_segment_by_key(SCARG(uap, key)); 536 if (segnum >= 0) { 537 error = shmget_existing(p, uap, mode, segnum, retval); 538 if (error == EAGAIN) 539 goto again; 540 return error; 541 } 542 if ((SCARG(uap, shmflg) & IPC_CREAT) == 0) 543 return ENOENT; 544 } 545 return shmget_allocate_segment(p, uap, mode, retval); 546 } 547 548 void 549 shmfork(vm1, vm2) 550 struct vmspace *vm1, *vm2; 551 { 552 struct shmmap_state *shmmap_s; 553 size_t size; 554 int i; 555 556 if (vm1->vm_shm == NULL) { 557 vm2->vm_shm = NULL; 558 return; 559 } 560 561 size = shminfo.shmseg * sizeof(struct shmmap_state); 562 shmmap_s = malloc(size, M_SHM, M_WAITOK); 563 memcpy(shmmap_s, vm1->vm_shm, size); 564 vm2->vm_shm = (caddr_t)shmmap_s; 565 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 566 if (shmmap_s->shmid != -1) 567 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 568 } 569 570 void 571 shmexit(vm) 572 struct vmspace *vm; 573 { 574 struct shmmap_state *shmmap_s; 575 int i; 576 577 shmmap_s = (struct shmmap_state *)vm->vm_shm; 578 if (shmmap_s == NULL) 579 return; 580 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 581 if (shmmap_s->shmid != -1) 582 shm_delete_mapping(vm, shmmap_s); 583 free(vm->vm_shm, M_SHM); 584 vm->vm_shm = NULL; 585 } 586 587 void 588 shminit() 589 { 590 int i; 591 592 shminfo.shmmax *= PAGE_SIZE; 593 594 for (i = 0; i < shminfo.shmmni; i++) { 595 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 596 shmsegs[i].shm_perm._seq = 0; 597 } 598 shm_last_free = 0; 599 shm_nused = 0; 600 shm_committed = 0; 601 } 602
Indexes created Tue Sep 30 20:09:53 GMT 2025