sysv_shm.c revision 1.85
1 /* $NetBSD: sysv_shm.c,v 1.85 2005/11/10 18:45:20 christos 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 1.85 2005/11/10 18:45:20 christos 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/sa.h> 84 #include <sys/syscallargs.h> 85 #include <sys/queue.h> 86 #include <sys/pool.h> 87 88 #include <uvm/uvm_extern.h> 89 #include <uvm/uvm_object.h> 90 91 struct shmid_ds *shm_find_segment_by_shmid(int); 92 93 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments"); 94 95 /* 96 * Provides the following externally accessible functions: 97 * 98 * shminit(void); initialization 99 * shmexit(struct vmspace *) cleanup 100 * shmfork(struct vmspace *, struct vmspace *) fork handling 101 * 102 * Structures: 103 * shmsegs (an array of 'struct shmid_ds') 104 * per proc array of 'struct shmmap_state' 105 */ 106 107 int shm_nused; 108 struct shmid_ds *shmsegs; 109 110 struct shmmap_entry { 111 SLIST_ENTRY(shmmap_entry) next; 112 vaddr_t va; 113 int shmid; 114 }; 115 116 static int shm_last_free, shm_committed; 117 118 static POOL_INIT(shmmap_entry_pool, sizeof(struct shmmap_entry), 0, 0, 0, 119 "shmmp", &pool_allocator_nointr); 120 121 struct shmmap_state { 122 unsigned int nitems; 123 unsigned int nrefs; 124 SLIST_HEAD(, shmmap_entry) entries; 125 }; 126 127 static int shm_find_segment_by_key(key_t); 128 static void shm_deallocate_segment(struct shmid_ds *); 129 static void shm_delete_mapping(struct vmspace *, struct shmmap_state *, 130 struct shmmap_entry *); 131 static int shmget_existing(struct proc *, struct sys_shmget_args *, 132 int, int, register_t *); 133 static int shmget_allocate_segment(struct proc *, struct sys_shmget_args *, 134 int, register_t *); 135 static struct shmmap_state *shmmap_getprivate(struct proc *); 136 static struct shmmap_entry *shm_find_mapping(struct shmmap_state *, vaddr_t); 137 138 static int 139 shm_find_segment_by_key(key) 140 key_t key; 141 { 142 int i; 143 144 for (i = 0; i < shminfo.shmmni; i++) 145 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 146 shmsegs[i].shm_perm._key == key) 147 return i; 148 return -1; 149 } 150 151 struct shmid_ds * 152 shm_find_segment_by_shmid(shmid) 153 int shmid; 154 { 155 int segnum; 156 struct shmid_ds *shmseg; 157 158 segnum = IPCID_TO_IX(shmid); 159 if (segnum < 0 || segnum >= shminfo.shmmni) 160 return NULL; 161 shmseg = &shmsegs[segnum]; 162 if ((shmseg->shm_perm.mode & SHMSEG_ALLOCATED) == 0) 163 return NULL; 164 if ((shmseg->shm_perm.mode & (SHMSEG_REMOVED|SHMSEG_RMLINGER)) == SHMSEG_REMOVED) 165 return NULL; 166 if (shmseg->shm_perm._seq != IPCID_TO_SEQ(shmid)) 167 return NULL; 168 return shmseg; 169 } 170 171 static void 172 shm_deallocate_segment(shmseg) 173 struct shmid_ds *shmseg; 174 { 175 struct uvm_object *uobj = shmseg->_shm_internal; 176 size_t size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 177 178 #ifdef SHMDEBUG 179 printf("shm freeing key 0x%lx seq 0x%x\n", 180 shmseg->shm_perm._key, shmseg->shm_perm._seq); 181 #endif 182 183 (*uobj->pgops->pgo_detach)(uobj); 184 shmseg->_shm_internal = NULL; 185 shm_committed -= btoc(size); 186 shmseg->shm_perm.mode = SHMSEG_FREE; 187 shm_nused--; 188 } 189 190 static void 191 shm_delete_mapping(vm, shmmap_s, shmmap_se) 192 struct vmspace *vm; 193 struct shmmap_state *shmmap_s; 194 struct shmmap_entry *shmmap_se; 195 { 196 struct shmid_ds *shmseg; 197 int segnum; 198 size_t size; 199 200 segnum = IPCID_TO_IX(shmmap_se->shmid); 201 #ifdef DEBUG 202 if (segnum < 0 || segnum >= shminfo.shmmni) 203 panic("shm_delete_mapping: vmspace %p state %p entry %p - " 204 "entry segment ID bad (%d)", 205 vm, shmmap_s, shmmap_se, segnum); 206 #endif 207 shmseg = &shmsegs[segnum]; 208 size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 209 uvm_deallocate(&vm->vm_map, shmmap_se->va, size); 210 SLIST_REMOVE(&shmmap_s->entries, shmmap_se, shmmap_entry, next); 211 shmmap_s->nitems--; 212 pool_put(&shmmap_entry_pool, shmmap_se); 213 shmseg->shm_dtime = time.tv_sec; 214 if ((--shmseg->shm_nattch <= 0) && 215 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 216 shm_deallocate_segment(shmseg); 217 shm_last_free = segnum; 218 } 219 } 220 221 /* 222 * Get a non-shared shm map for that vmspace. 223 * 3 cases: 224 * - no shm map present: create a fresh one 225 * - a shm map with refcount=1, just used by ourselves: fine 226 * - a shared shm map: copy to a fresh one and adjust refcounts 227 */ 228 static struct shmmap_state * 229 shmmap_getprivate(struct proc *p) 230 { 231 struct shmmap_state *oshmmap_s, *shmmap_s; 232 struct shmmap_entry *oshmmap_se, *shmmap_se; 233 234 oshmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 235 if (oshmmap_s && oshmmap_s->nrefs == 1) 236 return (oshmmap_s); 237 238 shmmap_s = malloc(sizeof(struct shmmap_state), M_SHM, M_WAITOK); 239 memset(shmmap_s, 0, sizeof(struct shmmap_state)); 240 shmmap_s->nrefs = 1; 241 SLIST_INIT(&shmmap_s->entries); 242 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 243 244 if (!oshmmap_s) 245 return (shmmap_s); 246 247 #ifdef SHMDEBUG 248 printf("shmmap_getprivate: vm %p split (%d entries), was used by %d\n", 249 p->p_vmspace, oshmmap_s->nitems, oshmmap_s->nrefs); 250 #endif 251 SLIST_FOREACH(oshmmap_se, &oshmmap_s->entries, next) { 252 shmmap_se = pool_get(&shmmap_entry_pool, PR_WAITOK); 253 shmmap_se->va = oshmmap_se->va; 254 shmmap_se->shmid = oshmmap_se->shmid; 255 SLIST_INSERT_HEAD(&shmmap_s->entries, shmmap_se, next); 256 } 257 shmmap_s->nitems = oshmmap_s->nitems; 258 oshmmap_s->nrefs--; 259 return (shmmap_s); 260 } 261 262 static struct shmmap_entry * 263 shm_find_mapping(map, va) 264 struct shmmap_state *map; 265 vaddr_t va; 266 { 267 struct shmmap_entry *shmmap_se; 268 269 SLIST_FOREACH(shmmap_se, &map->entries, next) { 270 if (shmmap_se->va == va) 271 return shmmap_se; 272 } 273 return 0; 274 } 275 276 int 277 sys_shmdt(l, v, retval) 278 struct lwp *l; 279 void *v; 280 register_t *retval; 281 { 282 struct sys_shmdt_args /* { 283 syscallarg(const void *) shmaddr; 284 } */ *uap = v; 285 struct proc *p = l->l_proc; 286 struct shmmap_state *shmmap_s, *shmmap_s1; 287 struct shmmap_entry *shmmap_se; 288 289 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 290 if (shmmap_s == NULL) 291 return EINVAL; 292 293 shmmap_se = shm_find_mapping(shmmap_s, (vaddr_t)SCARG(uap, shmaddr)); 294 if (!shmmap_se) 295 return EINVAL; 296 297 shmmap_s1 = shmmap_getprivate(p); 298 if (shmmap_s1 != shmmap_s) { 299 /* map has been copied, lookup entry in new map */ 300 shmmap_se = shm_find_mapping(shmmap_s1, 301 (vaddr_t)SCARG(uap, shmaddr)); 302 KASSERT(shmmap_se != NULL); 303 } 304 #ifdef SHMDEBUG 305 printf("shmdt: vm %p: remove %d @%lx\n", 306 p->p_vmspace, shmmap_se->shmid, shmmap_se->va); 307 #endif 308 shm_delete_mapping(p->p_vmspace, shmmap_s1, shmmap_se); 309 return 0; 310 } 311 312 int 313 sys_shmat(l, v, retval) 314 struct lwp *l; 315 void *v; 316 register_t *retval; 317 { 318 struct sys_shmat_args /* { 319 syscallarg(int) shmid; 320 syscallarg(const void *) shmaddr; 321 syscallarg(int) shmflg; 322 } */ *uap = v; 323 int error, flags; 324 struct proc *p = l->l_proc; 325 struct ucred *cred = p->p_ucred; 326 struct shmid_ds *shmseg; 327 struct shmmap_state *shmmap_s; 328 struct uvm_object *uobj; 329 vaddr_t attach_va; 330 vm_prot_t prot; 331 vsize_t size; 332 struct shmmap_entry *shmmap_se; 333 334 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 335 if (shmseg == NULL) 336 return EINVAL; 337 error = ipcperm(cred, &shmseg->shm_perm, 338 (SCARG(uap, shmflg) & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 339 if (error) 340 return error; 341 342 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 343 if (shmmap_s && shmmap_s->nitems >= shminfo.shmseg) 344 return EMFILE; 345 346 size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 347 prot = VM_PROT_READ; 348 if ((SCARG(uap, shmflg) & SHM_RDONLY) == 0) 349 prot |= VM_PROT_WRITE; 350 flags = MAP_ANON | MAP_SHARED; 351 if (SCARG(uap, shmaddr)) { 352 flags |= MAP_FIXED; 353 if (SCARG(uap, shmflg) & SHM_RND) 354 attach_va = 355 (vaddr_t)SCARG(uap, shmaddr) & ~(SHMLBA-1); 356 else if (((vaddr_t)SCARG(uap, shmaddr) & (SHMLBA-1)) == 0) 357 attach_va = (vaddr_t)SCARG(uap, shmaddr); 358 else 359 return EINVAL; 360 } else { 361 /* This is just a hint to uvm_mmap() about where to put it. */ 362 attach_va = p->p_emul->e_vm_default_addr(p, 363 (vaddr_t)p->p_vmspace->vm_daddr, size); 364 } 365 uobj = shmseg->_shm_internal; 366 (*uobj->pgops->pgo_reference)(uobj); 367 error = uvm_map(&p->p_vmspace->vm_map, &attach_va, size, 368 uobj, 0, 0, 369 UVM_MAPFLAG(prot, prot, UVM_INH_SHARE, UVM_ADV_RANDOM, 0)); 370 if (error) { 371 (*uobj->pgops->pgo_detach)(uobj); 372 return error; 373 } 374 shmmap_se = pool_get(&shmmap_entry_pool, PR_WAITOK); 375 shmmap_se->va = attach_va; 376 shmmap_se->shmid = SCARG(uap, shmid); 377 shmmap_s = shmmap_getprivate(p); 378 #ifdef SHMDEBUG 379 printf("shmat: vm %p: add %d @%lx\n", p->p_vmspace, shmmap_se->shmid, attach_va); 380 #endif 381 SLIST_INSERT_HEAD(&shmmap_s->entries, shmmap_se, next); 382 shmmap_s->nitems++; 383 shmseg->shm_lpid = p->p_pid; 384 shmseg->shm_atime = time.tv_sec; 385 shmseg->shm_nattch++; 386 387 retval[0] = attach_va; 388 return 0; 389 } 390 391 int 392 sys___shmctl13(l, v, retval) 393 struct lwp *l; 394 void *v; 395 register_t *retval; 396 { 397 struct sys___shmctl13_args /* { 398 syscallarg(int) shmid; 399 syscallarg(int) cmd; 400 syscallarg(struct shmid_ds *) buf; 401 } */ *uap = v; 402 struct proc *p = l->l_proc; 403 struct shmid_ds shmbuf; 404 int cmd, error; 405 406 cmd = SCARG(uap, cmd); 407 408 if (cmd == IPC_SET) { 409 error = copyin(SCARG(uap, buf), &shmbuf, sizeof(shmbuf)); 410 if (error) 411 return (error); 412 } 413 414 error = shmctl1(p, SCARG(uap, shmid), cmd, 415 (cmd == IPC_SET || cmd == IPC_STAT) ? &shmbuf : NULL); 416 417 if (error == 0 && cmd == IPC_STAT) 418 error = copyout(&shmbuf, SCARG(uap, buf), sizeof(shmbuf)); 419 420 return (error); 421 } 422 423 int 424 shmctl1(p, shmid, cmd, shmbuf) 425 struct proc *p; 426 int shmid; 427 int cmd; 428 struct shmid_ds *shmbuf; 429 { 430 struct ucred *cred = p->p_ucred; 431 struct shmid_ds *shmseg; 432 int error = 0; 433 434 shmseg = shm_find_segment_by_shmid(shmid); 435 if (shmseg == NULL) 436 return EINVAL; 437 switch (cmd) { 438 case IPC_STAT: 439 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) != 0) 440 return error; 441 memcpy(shmbuf, shmseg, sizeof(struct shmid_ds)); 442 break; 443 case IPC_SET: 444 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 445 return error; 446 shmseg->shm_perm.uid = shmbuf->shm_perm.uid; 447 shmseg->shm_perm.gid = shmbuf->shm_perm.gid; 448 shmseg->shm_perm.mode = 449 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 450 (shmbuf->shm_perm.mode & ACCESSPERMS); 451 shmseg->shm_ctime = time.tv_sec; 452 break; 453 case IPC_RMID: 454 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 455 return error; 456 shmseg->shm_perm._key = IPC_PRIVATE; 457 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 458 if (shmseg->shm_nattch <= 0) { 459 shm_deallocate_segment(shmseg); 460 shm_last_free = IPCID_TO_IX(shmid); 461 } 462 break; 463 case SHM_LOCK: 464 case SHM_UNLOCK: 465 default: 466 return EINVAL; 467 } 468 return 0; 469 } 470 471 static int 472 shmget_existing(p, uap, mode, segnum, retval) 473 struct proc *p; 474 struct sys_shmget_args /* { 475 syscallarg(key_t) key; 476 syscallarg(size_t) size; 477 syscallarg(int) shmflg; 478 } */ *uap; 479 int mode; 480 int segnum; 481 register_t *retval; 482 { 483 struct shmid_ds *shmseg; 484 struct ucred *cred = p->p_ucred; 485 int error; 486 487 shmseg = &shmsegs[segnum]; 488 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 489 /* 490 * This segment is in the process of being allocated. Wait 491 * until it's done, and look the key up again (in case the 492 * allocation failed or it was freed). 493 */ 494 shmseg->shm_perm.mode |= SHMSEG_WANTED; 495 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 496 if (error) 497 return error; 498 return EAGAIN; 499 } 500 if ((error = ipcperm(cred, &shmseg->shm_perm, mode)) != 0) 501 return error; 502 if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz) 503 return EINVAL; 504 if ((SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL)) == 505 (IPC_CREAT | IPC_EXCL)) 506 return EEXIST; 507 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 508 return 0; 509 } 510 511 static int 512 shmget_allocate_segment(p, uap, mode, retval) 513 struct proc *p; 514 struct sys_shmget_args /* { 515 syscallarg(key_t) key; 516 syscallarg(size_t) size; 517 syscallarg(int) shmflg; 518 } */ *uap; 519 int mode; 520 register_t *retval; 521 { 522 int i, segnum, shmid, size; 523 struct ucred *cred = p->p_ucred; 524 struct shmid_ds *shmseg; 525 int error = 0; 526 527 if (SCARG(uap, size) < shminfo.shmmin || 528 SCARG(uap, size) > shminfo.shmmax) 529 return EINVAL; 530 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 531 return ENOSPC; 532 size = (SCARG(uap, size) + PGOFSET) & ~PGOFSET; 533 if (shm_committed + btoc(size) > shminfo.shmall) 534 return ENOMEM; 535 if (shm_last_free < 0) { 536 for (i = 0; i < shminfo.shmmni; i++) 537 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 538 break; 539 if (i == shminfo.shmmni) 540 panic("shmseg free count inconsistent"); 541 segnum = i; 542 } else { 543 segnum = shm_last_free; 544 shm_last_free = -1; 545 } 546 shmseg = &shmsegs[segnum]; 547 /* 548 * In case we sleep in malloc(), mark the segment present but deleted 549 * so that noone else tries to create the same key. 550 */ 551 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 552 shmseg->shm_perm._key = SCARG(uap, key); 553 shmseg->shm_perm._seq = (shmseg->shm_perm._seq + 1) & 0x7fff; 554 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 555 556 shmseg->_shm_internal = uao_create(size, 0); 557 558 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 559 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 560 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 561 (mode & (ACCESSPERMS|SHMSEG_RMLINGER)) | SHMSEG_ALLOCATED; 562 shmseg->shm_segsz = SCARG(uap, size); 563 shmseg->shm_cpid = p->p_pid; 564 shmseg->shm_lpid = shmseg->shm_nattch = 0; 565 shmseg->shm_atime = shmseg->shm_dtime = 0; 566 shmseg->shm_ctime = time.tv_sec; 567 shm_committed += btoc(size); 568 shm_nused++; 569 570 *retval = shmid; 571 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 572 /* 573 * Somebody else wanted this key while we were asleep. Wake 574 * them up now. 575 */ 576 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 577 wakeup((caddr_t)shmseg); 578 } 579 return error; 580 } 581 582 int 583 sys_shmget(l, v, retval) 584 struct lwp *l; 585 void *v; 586 register_t *retval; 587 { 588 struct sys_shmget_args /* { 589 syscallarg(key_t) key; 590 syscallarg(int) size; 591 syscallarg(int) shmflg; 592 } */ *uap = v; 593 struct proc *p = l->l_proc; 594 int segnum, mode, error; 595 596 mode = SCARG(uap, shmflg) & ACCESSPERMS; 597 if (SCARG(uap, shmflg) & _SHM_RMLINGER) 598 mode |= SHMSEG_RMLINGER; 599 600 #ifdef SHMDEBUG 601 printf("shmget: key 0x%lx size 0x%x shmflg 0x%x mode 0x%x\n", 602 SCARG(uap, key), SCARG(uap, size), SCARG(uap, shmflg), mode); 603 #endif 604 605 if (SCARG(uap, key) != IPC_PRIVATE) { 606 again: 607 segnum = shm_find_segment_by_key(SCARG(uap, key)); 608 if (segnum >= 0) { 609 error = shmget_existing(p, uap, mode, segnum, retval); 610 if (error == EAGAIN) 611 goto again; 612 return error; 613 } 614 if ((SCARG(uap, shmflg) & IPC_CREAT) == 0) 615 return ENOENT; 616 } 617 return shmget_allocate_segment(p, uap, mode, retval); 618 } 619 620 void 621 shmfork(vm1, vm2) 622 struct vmspace *vm1, *vm2; 623 { 624 struct shmmap_state *shmmap_s; 625 struct shmmap_entry *shmmap_se; 626 627 vm2->vm_shm = vm1->vm_shm; 628 629 if (vm1->vm_shm == NULL) 630 return; 631 632 #ifdef SHMDEBUG 633 printf("shmfork %p->%p\n", vm1, vm2); 634 #endif 635 636 shmmap_s = (struct shmmap_state *)vm1->vm_shm; 637 638 SLIST_FOREACH(shmmap_se, &shmmap_s->entries, next) 639 shmsegs[IPCID_TO_IX(shmmap_se->shmid)].shm_nattch++; 640 shmmap_s->nrefs++; 641 } 642 643 void 644 shmexit(vm) 645 struct vmspace *vm; 646 { 647 struct shmmap_state *shmmap_s; 648 struct shmmap_entry *shmmap_se; 649 650 shmmap_s = (struct shmmap_state *)vm->vm_shm; 651 if (shmmap_s == NULL) 652 return; 653 654 vm->vm_shm = NULL; 655 656 if (--shmmap_s->nrefs > 0) { 657 #ifdef SHMDEBUG 658 printf("shmexit: vm %p drop ref (%d entries), now used by %d\n", 659 vm, shmmap_s->nitems, shmmap_s->nrefs); 660 #endif 661 SLIST_FOREACH(shmmap_se, &shmmap_s->entries, next) 662 shmsegs[IPCID_TO_IX(shmmap_se->shmid)].shm_nattch--; 663 return; 664 } 665 666 #ifdef SHMDEBUG 667 printf("shmexit: vm %p cleanup (%d entries)\n", vm, shmmap_s->nitems); 668 #endif 669 while (!SLIST_EMPTY(&shmmap_s->entries)) { 670 shmmap_se = SLIST_FIRST(&shmmap_s->entries); 671 shm_delete_mapping(vm, shmmap_s, shmmap_se); 672 } 673 KASSERT(shmmap_s->nitems == 0); 674 free(shmmap_s, M_SHM); 675 } 676 677 void 678 shminit() 679 { 680 int i, sz; 681 vaddr_t v; 682 683 /* Allocate pageable memory for our structures */ 684 sz = shminfo.shmmni * sizeof(struct shmid_ds); 685 v = uvm_km_alloc(kernel_map, round_page(sz), 0, UVM_KMF_WIRED); 686 if (v == 0) 687 panic("sysv_shm: cannot allocate memory"); 688 shmsegs = (void *)v; 689 690 shminfo.shmmax *= PAGE_SIZE; 691 692 for (i = 0; i < shminfo.shmmni; i++) { 693 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 694 shmsegs[i].shm_perm._seq = 0; 695 } 696 shm_last_free = 0; 697 shm_nused = 0; 698 shm_committed = 0; 699 } 700
Indexes created Wed Sep 24 05:09:52 GMT 2025