sysv_shm.c revision 1.84
1 /* $NetBSD: sysv_shm.c,v 1.84 2005/04/01 11:59:37 yamt 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 1.84 2005/04/01 11:59:37 yamt 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 #define SHMSEG_FREE 0x0200 108 #define SHMSEG_REMOVED 0x0400 109 #define SHMSEG_ALLOCATED 0x0800 110 #define SHMSEG_WANTED 0x1000 111 #define SHMSEG_RMLINGER 0x2000 112 113 static int shm_last_free, shm_nused, shm_committed; 114 struct shmid_ds *shmsegs; 115 116 struct shmmap_entry { 117 SLIST_ENTRY(shmmap_entry) next; 118 vaddr_t va; 119 int shmid; 120 }; 121 122 static POOL_INIT(shmmap_entry_pool, sizeof(struct shmmap_entry), 0, 0, 0, 123 "shmmp", &pool_allocator_nointr); 124 125 struct shmmap_state { 126 unsigned int nitems; 127 unsigned int nrefs; 128 SLIST_HEAD(, shmmap_entry) entries; 129 }; 130 131 static int shm_find_segment_by_key(key_t); 132 static void shm_deallocate_segment(struct shmid_ds *); 133 static void shm_delete_mapping(struct vmspace *, struct shmmap_state *, 134 struct shmmap_entry *); 135 static int shmget_existing(struct proc *, struct sys_shmget_args *, 136 int, int, register_t *); 137 static int shmget_allocate_segment(struct proc *, struct sys_shmget_args *, 138 int, register_t *); 139 static struct shmmap_state *shmmap_getprivate(struct proc *); 140 static struct shmmap_entry *shm_find_mapping(struct shmmap_state *, vaddr_t); 141 142 static int 143 shm_find_segment_by_key(key) 144 key_t key; 145 { 146 int i; 147 148 for (i = 0; i < shminfo.shmmni; i++) 149 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 150 shmsegs[i].shm_perm._key == key) 151 return i; 152 return -1; 153 } 154 155 struct shmid_ds * 156 shm_find_segment_by_shmid(shmid) 157 int shmid; 158 { 159 int segnum; 160 struct shmid_ds *shmseg; 161 162 segnum = IPCID_TO_IX(shmid); 163 if (segnum < 0 || segnum >= shminfo.shmmni) 164 return NULL; 165 shmseg = &shmsegs[segnum]; 166 if ((shmseg->shm_perm.mode & SHMSEG_ALLOCATED) == 0) 167 return NULL; 168 if ((shmseg->shm_perm.mode & (SHMSEG_REMOVED|SHMSEG_RMLINGER)) == SHMSEG_REMOVED) 169 return NULL; 170 if (shmseg->shm_perm._seq != IPCID_TO_SEQ(shmid)) 171 return NULL; 172 return shmseg; 173 } 174 175 static void 176 shm_deallocate_segment(shmseg) 177 struct shmid_ds *shmseg; 178 { 179 struct uvm_object *uobj = shmseg->_shm_internal; 180 size_t size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 181 182 (*uobj->pgops->pgo_detach)(uobj); 183 shmseg->_shm_internal = NULL; 184 shm_committed -= btoc(size); 185 shmseg->shm_perm.mode = SHMSEG_FREE; 186 shm_nused--; 187 } 188 189 static void 190 shm_delete_mapping(vm, shmmap_s, shmmap_se) 191 struct vmspace *vm; 192 struct shmmap_state *shmmap_s; 193 struct shmmap_entry *shmmap_se; 194 { 195 struct shmid_ds *shmseg; 196 int segnum; 197 size_t size; 198 199 segnum = IPCID_TO_IX(shmmap_se->shmid); 200 #ifdef DEBUG 201 if (segnum < 0 || segnum >= shminfo.shmmni) 202 panic("shm_delete_mapping: vmspace %p state %p entry %p - " 203 "entry segment ID bad (%d)", 204 vm, shmmap_s, shmmap_se, segnum); 205 #endif 206 shmseg = &shmsegs[segnum]; 207 size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 208 uvm_deallocate(&vm->vm_map, shmmap_se->va, size); 209 SLIST_REMOVE(&shmmap_s->entries, shmmap_se, shmmap_entry, next); 210 shmmap_s->nitems--; 211 pool_put(&shmmap_entry_pool, shmmap_se); 212 shmseg->shm_dtime = time.tv_sec; 213 if ((--shmseg->shm_nattch <= 0) && 214 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 215 shm_deallocate_segment(shmseg); 216 shm_last_free = segnum; 217 } 218 } 219 220 /* 221 * Get a non-shared shm map for that vmspace. 222 * 3 cases: 223 * - no shm map present: create a fresh one 224 * - a shm map with refcount=1, just used by ourselves: fine 225 * - a shared shm map: copy to a fresh one and adjust refcounts 226 */ 227 static struct shmmap_state * 228 shmmap_getprivate(struct proc *p) 229 { 230 struct shmmap_state *oshmmap_s, *shmmap_s; 231 struct shmmap_entry *oshmmap_se, *shmmap_se; 232 233 oshmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 234 if (oshmmap_s && oshmmap_s->nrefs == 1) 235 return (oshmmap_s); 236 237 shmmap_s = malloc(sizeof(struct shmmap_state), M_SHM, M_WAITOK); 238 memset(shmmap_s, 0, sizeof(struct shmmap_state)); 239 shmmap_s->nrefs = 1; 240 SLIST_INIT(&shmmap_s->entries); 241 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 242 243 if (!oshmmap_s) 244 return (shmmap_s); 245 246 #ifdef SHMDEBUG 247 printf("shmmap_getprivate: vm %p split (%d entries), was used by %d\n", 248 p->p_vmspace, oshmmap_s->nitems, oshmmap_s->nrefs); 249 #endif 250 SLIST_FOREACH(oshmmap_se, &oshmmap_s->entries, next) { 251 shmmap_se = pool_get(&shmmap_entry_pool, PR_WAITOK); 252 shmmap_se->va = oshmmap_se->va; 253 shmmap_se->shmid = oshmmap_se->shmid; 254 SLIST_INSERT_HEAD(&shmmap_s->entries, shmmap_se, next); 255 } 256 shmmap_s->nitems = oshmmap_s->nitems; 257 oshmmap_s->nrefs--; 258 return (shmmap_s); 259 } 260 261 static struct shmmap_entry * 262 shm_find_mapping(map, va) 263 struct shmmap_state *map; 264 vaddr_t va; 265 { 266 struct shmmap_entry *shmmap_se; 267 268 SLIST_FOREACH(shmmap_se, &map->entries, next) { 269 if (shmmap_se->va == va) 270 return shmmap_se; 271 } 272 return 0; 273 } 274 275 int 276 sys_shmdt(l, v, retval) 277 struct lwp *l; 278 void *v; 279 register_t *retval; 280 { 281 struct sys_shmdt_args /* { 282 syscallarg(const void *) shmaddr; 283 } */ *uap = v; 284 struct proc *p = l->l_proc; 285 struct shmmap_state *shmmap_s, *shmmap_s1; 286 struct shmmap_entry *shmmap_se; 287 288 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 289 if (shmmap_s == NULL) 290 return EINVAL; 291 292 shmmap_se = shm_find_mapping(shmmap_s, (vaddr_t)SCARG(uap, shmaddr)); 293 if (!shmmap_se) 294 return EINVAL; 295 296 shmmap_s1 = shmmap_getprivate(p); 297 if (shmmap_s1 != shmmap_s) { 298 /* map has been copied, lookup entry in new map */ 299 shmmap_se = shm_find_mapping(shmmap_s1, 300 (vaddr_t)SCARG(uap, shmaddr)); 301 KASSERT(shmmap_se != NULL); 302 } 303 #ifdef SHMDEBUG 304 printf("shmdt: vm %p: remove %d @%lx\n", 305 p->p_vmspace, shmmap_se->shmid, shmmap_se->va); 306 #endif 307 shm_delete_mapping(p->p_vmspace, shmmap_s1, shmmap_se); 308 return 0; 309 } 310 311 int 312 sys_shmat(l, v, retval) 313 struct lwp *l; 314 void *v; 315 register_t *retval; 316 { 317 struct sys_shmat_args /* { 318 syscallarg(int) shmid; 319 syscallarg(const void *) shmaddr; 320 syscallarg(int) shmflg; 321 } */ *uap = v; 322 int error, flags; 323 struct proc *p = l->l_proc; 324 struct ucred *cred = p->p_ucred; 325 struct shmid_ds *shmseg; 326 struct shmmap_state *shmmap_s; 327 struct uvm_object *uobj; 328 vaddr_t attach_va; 329 vm_prot_t prot; 330 vsize_t size; 331 struct shmmap_entry *shmmap_se; 332 333 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 334 if (shmseg == NULL) 335 return EINVAL; 336 error = ipcperm(cred, &shmseg->shm_perm, 337 (SCARG(uap, shmflg) & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 338 if (error) 339 return error; 340 341 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 342 if (shmmap_s && shmmap_s->nitems >= shminfo.shmseg) 343 return EMFILE; 344 345 size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 346 prot = VM_PROT_READ; 347 if ((SCARG(uap, shmflg) & SHM_RDONLY) == 0) 348 prot |= VM_PROT_WRITE; 349 flags = MAP_ANON | MAP_SHARED; 350 if (SCARG(uap, shmaddr)) { 351 flags |= MAP_FIXED; 352 if (SCARG(uap, shmflg) & SHM_RND) 353 attach_va = 354 (vaddr_t)SCARG(uap, shmaddr) & ~(SHMLBA-1); 355 else if (((vaddr_t)SCARG(uap, shmaddr) & (SHMLBA-1)) == 0) 356 attach_va = (vaddr_t)SCARG(uap, shmaddr); 357 else 358 return EINVAL; 359 } else { 360 /* This is just a hint to uvm_mmap() about where to put it. */ 361 attach_va = p->p_emul->e_vm_default_addr(p, 362 (vaddr_t)p->p_vmspace->vm_daddr, size); 363 } 364 uobj = shmseg->_shm_internal; 365 (*uobj->pgops->pgo_reference)(uobj); 366 error = uvm_map(&p->p_vmspace->vm_map, &attach_va, size, 367 uobj, 0, 0, 368 UVM_MAPFLAG(prot, prot, UVM_INH_SHARE, UVM_ADV_RANDOM, 0)); 369 if (error) { 370 (*uobj->pgops->pgo_detach)(uobj); 371 return error; 372 } 373 shmmap_se = pool_get(&shmmap_entry_pool, PR_WAITOK); 374 shmmap_se->va = attach_va; 375 shmmap_se->shmid = SCARG(uap, shmid); 376 shmmap_s = shmmap_getprivate(p); 377 #ifdef SHMDEBUG 378 printf("shmat: vm %p: add %d @%lx\n", p->p_vmspace, shmid, attach_va); 379 #endif 380 SLIST_INSERT_HEAD(&shmmap_s->entries, shmmap_se, next); 381 shmmap_s->nitems++; 382 shmseg->shm_lpid = p->p_pid; 383 shmseg->shm_atime = time.tv_sec; 384 shmseg->shm_nattch++; 385 386 retval[0] = attach_va; 387 return 0; 388 } 389 390 int 391 sys___shmctl13(l, v, retval) 392 struct lwp *l; 393 void *v; 394 register_t *retval; 395 { 396 struct sys___shmctl13_args /* { 397 syscallarg(int) shmid; 398 syscallarg(int) cmd; 399 syscallarg(struct shmid_ds *) buf; 400 } */ *uap = v; 401 struct proc *p = l->l_proc; 402 struct shmid_ds shmbuf; 403 int cmd, error; 404 405 cmd = SCARG(uap, cmd); 406 407 if (cmd == IPC_SET) { 408 error = copyin(SCARG(uap, buf), &shmbuf, sizeof(shmbuf)); 409 if (error) 410 return (error); 411 } 412 413 error = shmctl1(p, SCARG(uap, shmid), cmd, 414 (cmd == IPC_SET || cmd == IPC_STAT) ? &shmbuf : NULL); 415 416 if (error == 0 && cmd == IPC_STAT) 417 error = copyout(&shmbuf, SCARG(uap, buf), sizeof(shmbuf)); 418 419 return (error); 420 } 421 422 int 423 shmctl1(p, shmid, cmd, shmbuf) 424 struct proc *p; 425 int shmid; 426 int cmd; 427 struct shmid_ds *shmbuf; 428 { 429 struct ucred *cred = p->p_ucred; 430 struct shmid_ds *shmseg; 431 int error = 0; 432 433 shmseg = shm_find_segment_by_shmid(shmid); 434 if (shmseg == NULL) 435 return EINVAL; 436 switch (cmd) { 437 case IPC_STAT: 438 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) != 0) 439 return error; 440 memcpy(shmbuf, shmseg, sizeof(struct shmid_ds)); 441 break; 442 case IPC_SET: 443 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 444 return error; 445 shmseg->shm_perm.uid = shmbuf->shm_perm.uid; 446 shmseg->shm_perm.gid = shmbuf->shm_perm.gid; 447 shmseg->shm_perm.mode = 448 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 449 (shmbuf->shm_perm.mode & ACCESSPERMS); 450 shmseg->shm_ctime = time.tv_sec; 451 break; 452 case IPC_RMID: 453 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 454 return error; 455 shmseg->shm_perm._key = IPC_PRIVATE; 456 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 457 if (shmseg->shm_nattch <= 0) { 458 shm_deallocate_segment(shmseg); 459 shm_last_free = IPCID_TO_IX(shmid); 460 } 461 break; 462 case SHM_LOCK: 463 case SHM_UNLOCK: 464 default: 465 return EINVAL; 466 } 467 return 0; 468 } 469 470 static int 471 shmget_existing(p, uap, mode, segnum, retval) 472 struct proc *p; 473 struct sys_shmget_args /* { 474 syscallarg(key_t) key; 475 syscallarg(size_t) size; 476 syscallarg(int) shmflg; 477 } */ *uap; 478 int mode; 479 int segnum; 480 register_t *retval; 481 { 482 struct shmid_ds *shmseg; 483 struct ucred *cred = p->p_ucred; 484 int error; 485 486 shmseg = &shmsegs[segnum]; 487 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 488 /* 489 * This segment is in the process of being allocated. Wait 490 * until it's done, and look the key up again (in case the 491 * allocation failed or it was freed). 492 */ 493 shmseg->shm_perm.mode |= SHMSEG_WANTED; 494 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 495 if (error) 496 return error; 497 return EAGAIN; 498 } 499 if ((error = ipcperm(cred, &shmseg->shm_perm, mode)) != 0) 500 return error; 501 if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz) 502 return EINVAL; 503 if ((SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL)) == 504 (IPC_CREAT | IPC_EXCL)) 505 return EEXIST; 506 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 507 return 0; 508 } 509 510 static int 511 shmget_allocate_segment(p, uap, mode, retval) 512 struct proc *p; 513 struct sys_shmget_args /* { 514 syscallarg(key_t) key; 515 syscallarg(size_t) size; 516 syscallarg(int) shmflg; 517 } */ *uap; 518 int mode; 519 register_t *retval; 520 { 521 int i, segnum, shmid, size; 522 struct ucred *cred = p->p_ucred; 523 struct shmid_ds *shmseg; 524 int error = 0; 525 526 if (SCARG(uap, size) < shminfo.shmmin || 527 SCARG(uap, size) > shminfo.shmmax) 528 return EINVAL; 529 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 530 return ENOSPC; 531 size = (SCARG(uap, size) + PGOFSET) & ~PGOFSET; 532 if (shm_committed + btoc(size) > shminfo.shmall) 533 return ENOMEM; 534 if (shm_last_free < 0) { 535 for (i = 0; i < shminfo.shmmni; i++) 536 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 537 break; 538 if (i == shminfo.shmmni) 539 panic("shmseg free count inconsistent"); 540 segnum = i; 541 } else { 542 segnum = shm_last_free; 543 shm_last_free = -1; 544 } 545 shmseg = &shmsegs[segnum]; 546 /* 547 * In case we sleep in malloc(), mark the segment present but deleted 548 * so that noone else tries to create the same key. 549 */ 550 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 551 shmseg->shm_perm._key = SCARG(uap, key); 552 shmseg->shm_perm._seq = (shmseg->shm_perm._seq + 1) & 0x7fff; 553 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 554 555 shmseg->_shm_internal = uao_create(size, 0); 556 557 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 558 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 559 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 560 (mode & (ACCESSPERMS|SHMSEG_RMLINGER)) | SHMSEG_ALLOCATED; 561 shmseg->shm_segsz = SCARG(uap, size); 562 shmseg->shm_cpid = p->p_pid; 563 shmseg->shm_lpid = shmseg->shm_nattch = 0; 564 shmseg->shm_atime = shmseg->shm_dtime = 0; 565 shmseg->shm_ctime = time.tv_sec; 566 shm_committed += btoc(size); 567 shm_nused++; 568 569 *retval = shmid; 570 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 571 /* 572 * Somebody else wanted this key while we were asleep. Wake 573 * them up now. 574 */ 575 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 576 wakeup((caddr_t)shmseg); 577 } 578 return error; 579 } 580 581 int 582 sys_shmget(l, v, retval) 583 struct lwp *l; 584 void *v; 585 register_t *retval; 586 { 587 struct sys_shmget_args /* { 588 syscallarg(key_t) key; 589 syscallarg(int) size; 590 syscallarg(int) shmflg; 591 } */ *uap = v; 592 struct proc *p = l->l_proc; 593 int segnum, mode, error; 594 595 mode = SCARG(uap, shmflg) & ACCESSPERMS; 596 if (SCARG(uap, shmflg) & _SHM_RMLINGER) 597 mode |= SHMSEG_RMLINGER; 598 599 if (SCARG(uap, key) != IPC_PRIVATE) { 600 again: 601 segnum = shm_find_segment_by_key(SCARG(uap, key)); 602 if (segnum >= 0) { 603 error = shmget_existing(p, uap, mode, segnum, retval); 604 if (error == EAGAIN) 605 goto again; 606 return error; 607 } 608 if ((SCARG(uap, shmflg) & IPC_CREAT) == 0) 609 return ENOENT; 610 } 611 return shmget_allocate_segment(p, uap, mode, retval); 612 } 613 614 void 615 shmfork(vm1, vm2) 616 struct vmspace *vm1, *vm2; 617 { 618 struct shmmap_state *shmmap_s; 619 struct shmmap_entry *shmmap_se; 620 621 vm2->vm_shm = vm1->vm_shm; 622 623 if (vm1->vm_shm == NULL) 624 return; 625 626 #ifdef SHMDEBUG 627 printf("shmfork %p->%p\n", vm1, vm2); 628 #endif 629 630 shmmap_s = (struct shmmap_state *)vm1->vm_shm; 631 632 SLIST_FOREACH(shmmap_se, &shmmap_s->entries, next) 633 shmsegs[IPCID_TO_IX(shmmap_se->shmid)].shm_nattch++; 634 shmmap_s->nrefs++; 635 } 636 637 void 638 shmexit(vm) 639 struct vmspace *vm; 640 { 641 struct shmmap_state *shmmap_s; 642 struct shmmap_entry *shmmap_se; 643 644 shmmap_s = (struct shmmap_state *)vm->vm_shm; 645 if (shmmap_s == NULL) 646 return; 647 648 vm->vm_shm = NULL; 649 650 if (--shmmap_s->nrefs > 0) { 651 #ifdef SHMDEBUG 652 printf("shmexit: vm %p drop ref (%d entries), now used by %d\n", 653 vm, shmmap_s->nitems, shmmap_s->nrefs); 654 #endif 655 SLIST_FOREACH(shmmap_se, &shmmap_s->entries, next) 656 shmsegs[IPCID_TO_IX(shmmap_se->shmid)].shm_nattch--; 657 return; 658 } 659 660 #ifdef SHMDEBUG 661 printf("shmexit: vm %p cleanup (%d entries)\n", vm, shmmap_s->nitems); 662 #endif 663 while (!SLIST_EMPTY(&shmmap_s->entries)) { 664 shmmap_se = SLIST_FIRST(&shmmap_s->entries); 665 shm_delete_mapping(vm, shmmap_s, shmmap_se); 666 } 667 KASSERT(shmmap_s->nitems == 0); 668 free(shmmap_s, M_SHM); 669 } 670 671 void 672 shminit() 673 { 674 int i, sz; 675 vaddr_t v; 676 677 /* Allocate pageable memory for our structures */ 678 sz = shminfo.shmmni * sizeof(struct shmid_ds); 679 v = uvm_km_alloc(kernel_map, round_page(sz), 0, UVM_KMF_WIRED); 680 if (v == 0) 681 panic("sysv_shm: cannot allocate memory"); 682 shmsegs = (void *)v; 683 684 shminfo.shmmax *= PAGE_SIZE; 685 686 for (i = 0; i < shminfo.shmmni; i++) { 687 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 688 shmsegs[i].shm_perm._seq = 0; 689 } 690 shm_last_free = 0; 691 shm_nused = 0; 692 shm_committed = 0; 693 } 694
Indexes created Tue Sep 23 14:10:03 GMT 2025