sysv_shm.c revision 1.87
1 /* $NetBSD: sysv_shm.c,v 1.87 2006/05/14 21:15:11 elad 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 1.87 2006/05/14 21:15:11 elad 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 #include <sys/kauth.h> 88 89 #include <uvm/uvm_extern.h> 90 #include <uvm/uvm_object.h> 91 92 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments"); 93 94 /* 95 * Provides the following externally accessible functions: 96 * 97 * shminit(void); initialization 98 * shmexit(struct vmspace *) cleanup 99 * shmfork(struct vmspace *, struct vmspace *) fork handling 100 * 101 * Structures: 102 * shmsegs (an array of 'struct shmid_ds') 103 * per proc array of 'struct shmmap_state' 104 */ 105 106 int shm_nused; 107 struct shmid_ds *shmsegs; 108 109 struct shmmap_entry { 110 SLIST_ENTRY(shmmap_entry) next; 111 vaddr_t va; 112 int shmid; 113 }; 114 115 static int shm_last_free, shm_committed; 116 117 static POOL_INIT(shmmap_entry_pool, sizeof(struct shmmap_entry), 0, 0, 0, 118 "shmmp", &pool_allocator_nointr); 119 120 struct shmmap_state { 121 unsigned int nitems; 122 unsigned int nrefs; 123 SLIST_HEAD(, shmmap_entry) entries; 124 }; 125 126 static int shm_find_segment_by_key(key_t); 127 static void shm_deallocate_segment(struct shmid_ds *); 128 static void shm_delete_mapping(struct vmspace *, struct shmmap_state *, 129 struct shmmap_entry *); 130 static int shmget_existing(struct proc *, struct sys_shmget_args *, 131 int, int, register_t *); 132 static int shmget_allocate_segment(struct proc *, struct sys_shmget_args *, 133 int, register_t *); 134 static struct shmmap_state *shmmap_getprivate(struct proc *); 135 static struct shmmap_entry *shm_find_mapping(struct shmmap_state *, vaddr_t); 136 137 static int 138 shm_find_segment_by_key(key_t key) 139 { 140 int i; 141 142 for (i = 0; i < shminfo.shmmni; i++) 143 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 144 shmsegs[i].shm_perm._key == key) 145 return i; 146 return -1; 147 } 148 149 static struct shmid_ds * 150 shm_find_segment_by_shmid(int shmid) 151 { 152 int segnum; 153 struct shmid_ds *shmseg; 154 155 segnum = IPCID_TO_IX(shmid); 156 if (segnum < 0 || segnum >= shminfo.shmmni) 157 return NULL; 158 shmseg = &shmsegs[segnum]; 159 if ((shmseg->shm_perm.mode & SHMSEG_ALLOCATED) == 0) 160 return NULL; 161 if ((shmseg->shm_perm.mode & (SHMSEG_REMOVED|SHMSEG_RMLINGER)) == SHMSEG_REMOVED) 162 return NULL; 163 if (shmseg->shm_perm._seq != IPCID_TO_SEQ(shmid)) 164 return NULL; 165 return shmseg; 166 } 167 168 static void 169 shm_deallocate_segment(struct shmid_ds *shmseg) 170 { 171 struct uvm_object *uobj = shmseg->_shm_internal; 172 size_t size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 173 174 #ifdef SHMDEBUG 175 printf("shm freeing key 0x%lx seq 0x%x\n", 176 shmseg->shm_perm._key, shmseg->shm_perm._seq); 177 #endif 178 179 (*uobj->pgops->pgo_detach)(uobj); 180 shmseg->_shm_internal = NULL; 181 shm_committed -= btoc(size); 182 shmseg->shm_perm.mode = SHMSEG_FREE; 183 shm_nused--; 184 } 185 186 static void 187 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s, 188 struct shmmap_entry *shmmap_se) 189 { 190 struct shmid_ds *shmseg; 191 int segnum; 192 size_t size; 193 194 segnum = IPCID_TO_IX(shmmap_se->shmid); 195 #ifdef DEBUG 196 if (segnum < 0 || segnum >= shminfo.shmmni) 197 panic("shm_delete_mapping: vmspace %p state %p entry %p - " 198 "entry segment ID bad (%d)", 199 vm, shmmap_s, shmmap_se, segnum); 200 #endif 201 shmseg = &shmsegs[segnum]; 202 size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 203 uvm_deallocate(&vm->vm_map, shmmap_se->va, size); 204 SLIST_REMOVE(&shmmap_s->entries, shmmap_se, shmmap_entry, next); 205 shmmap_s->nitems--; 206 pool_put(&shmmap_entry_pool, shmmap_se); 207 shmseg->shm_dtime = time.tv_sec; 208 if ((--shmseg->shm_nattch <= 0) && 209 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 210 shm_deallocate_segment(shmseg); 211 shm_last_free = segnum; 212 } 213 } 214 215 /* 216 * Get a non-shared shm map for that vmspace. 217 * 3 cases: 218 * - no shm map present: create a fresh one 219 * - a shm map with refcount=1, just used by ourselves: fine 220 * - a shared shm map: copy to a fresh one and adjust refcounts 221 */ 222 static struct shmmap_state * 223 shmmap_getprivate(struct proc *p) 224 { 225 struct shmmap_state *oshmmap_s, *shmmap_s; 226 struct shmmap_entry *oshmmap_se, *shmmap_se; 227 228 oshmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 229 if (oshmmap_s && oshmmap_s->nrefs == 1) 230 return (oshmmap_s); 231 232 shmmap_s = malloc(sizeof(struct shmmap_state), M_SHM, M_WAITOK); 233 memset(shmmap_s, 0, sizeof(struct shmmap_state)); 234 shmmap_s->nrefs = 1; 235 SLIST_INIT(&shmmap_s->entries); 236 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 237 238 if (!oshmmap_s) 239 return (shmmap_s); 240 241 #ifdef SHMDEBUG 242 printf("shmmap_getprivate: vm %p split (%d entries), was used by %d\n", 243 p->p_vmspace, oshmmap_s->nitems, oshmmap_s->nrefs); 244 #endif 245 SLIST_FOREACH(oshmmap_se, &oshmmap_s->entries, next) { 246 shmmap_se = pool_get(&shmmap_entry_pool, PR_WAITOK); 247 shmmap_se->va = oshmmap_se->va; 248 shmmap_se->shmid = oshmmap_se->shmid; 249 SLIST_INSERT_HEAD(&shmmap_s->entries, shmmap_se, next); 250 } 251 shmmap_s->nitems = oshmmap_s->nitems; 252 oshmmap_s->nrefs--; 253 return (shmmap_s); 254 } 255 256 static struct shmmap_entry * 257 shm_find_mapping(struct shmmap_state *map, vaddr_t va) 258 { 259 struct shmmap_entry *shmmap_se; 260 261 SLIST_FOREACH(shmmap_se, &map->entries, next) { 262 if (shmmap_se->va == va) 263 return shmmap_se; 264 } 265 return 0; 266 } 267 268 int 269 sys_shmdt(struct lwp *l, void *v, register_t *retval) 270 { 271 struct sys_shmdt_args /* { 272 syscallarg(const void *) shmaddr; 273 } */ *uap = v; 274 struct proc *p = l->l_proc; 275 struct shmmap_state *shmmap_s, *shmmap_s1; 276 struct shmmap_entry *shmmap_se; 277 278 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 279 if (shmmap_s == NULL) 280 return EINVAL; 281 282 shmmap_se = shm_find_mapping(shmmap_s, (vaddr_t)SCARG(uap, shmaddr)); 283 if (!shmmap_se) 284 return EINVAL; 285 286 shmmap_s1 = shmmap_getprivate(p); 287 if (shmmap_s1 != shmmap_s) { 288 /* map has been copied, lookup entry in new map */ 289 shmmap_se = shm_find_mapping(shmmap_s1, 290 (vaddr_t)SCARG(uap, shmaddr)); 291 KASSERT(shmmap_se != NULL); 292 } 293 #ifdef SHMDEBUG 294 printf("shmdt: vm %p: remove %d @%lx\n", 295 p->p_vmspace, shmmap_se->shmid, shmmap_se->va); 296 #endif 297 shm_delete_mapping(p->p_vmspace, shmmap_s1, shmmap_se); 298 return 0; 299 } 300 301 int 302 sys_shmat(struct lwp *l, void *v, register_t *retval) 303 { 304 struct sys_shmat_args /* { 305 syscallarg(int) shmid; 306 syscallarg(const void *) shmaddr; 307 syscallarg(int) shmflg; 308 } */ *uap = v; 309 int error, flags; 310 struct proc *p = l->l_proc; 311 kauth_cred_t cred = p->p_cred; 312 struct shmid_ds *shmseg; 313 struct shmmap_state *shmmap_s; 314 struct uvm_object *uobj; 315 vaddr_t attach_va; 316 vm_prot_t prot; 317 vsize_t size; 318 struct shmmap_entry *shmmap_se; 319 320 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 321 if (shmseg == NULL) 322 return EINVAL; 323 error = ipcperm(cred, &shmseg->shm_perm, 324 (SCARG(uap, shmflg) & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 325 if (error) 326 return error; 327 328 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 329 if (shmmap_s && shmmap_s->nitems >= shminfo.shmseg) 330 return EMFILE; 331 332 size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 333 prot = VM_PROT_READ; 334 if ((SCARG(uap, shmflg) & SHM_RDONLY) == 0) 335 prot |= VM_PROT_WRITE; 336 flags = MAP_ANON | MAP_SHARED; 337 if (SCARG(uap, shmaddr)) { 338 flags |= MAP_FIXED; 339 if (SCARG(uap, shmflg) & SHM_RND) 340 attach_va = 341 (vaddr_t)SCARG(uap, shmaddr) & ~(SHMLBA-1); 342 else if (((vaddr_t)SCARG(uap, shmaddr) & (SHMLBA-1)) == 0) 343 attach_va = (vaddr_t)SCARG(uap, shmaddr); 344 else 345 return EINVAL; 346 } else { 347 /* This is just a hint to uvm_mmap() about where to put it. */ 348 attach_va = p->p_emul->e_vm_default_addr(p, 349 (vaddr_t)p->p_vmspace->vm_daddr, size); 350 } 351 uobj = shmseg->_shm_internal; 352 (*uobj->pgops->pgo_reference)(uobj); 353 error = uvm_map(&p->p_vmspace->vm_map, &attach_va, size, 354 uobj, 0, 0, 355 UVM_MAPFLAG(prot, prot, UVM_INH_SHARE, UVM_ADV_RANDOM, 0)); 356 if (error) { 357 (*uobj->pgops->pgo_detach)(uobj); 358 return error; 359 } 360 shmmap_se = pool_get(&shmmap_entry_pool, PR_WAITOK); 361 shmmap_se->va = attach_va; 362 shmmap_se->shmid = SCARG(uap, shmid); 363 shmmap_s = shmmap_getprivate(p); 364 #ifdef SHMDEBUG 365 printf("shmat: vm %p: add %d @%lx\n", p->p_vmspace, shmmap_se->shmid, attach_va); 366 #endif 367 SLIST_INSERT_HEAD(&shmmap_s->entries, shmmap_se, next); 368 shmmap_s->nitems++; 369 shmseg->shm_lpid = p->p_pid; 370 shmseg->shm_atime = time.tv_sec; 371 shmseg->shm_nattch++; 372 373 retval[0] = attach_va; 374 return 0; 375 } 376 377 int 378 sys___shmctl13(struct lwp *l, void *v, register_t *retval) 379 { 380 struct sys___shmctl13_args /* { 381 syscallarg(int) shmid; 382 syscallarg(int) cmd; 383 syscallarg(struct shmid_ds *) buf; 384 } */ *uap = v; 385 struct proc *p = l->l_proc; 386 struct shmid_ds shmbuf; 387 int cmd, error; 388 389 cmd = SCARG(uap, cmd); 390 391 if (cmd == IPC_SET) { 392 error = copyin(SCARG(uap, buf), &shmbuf, sizeof(shmbuf)); 393 if (error) 394 return (error); 395 } 396 397 error = shmctl1(p, SCARG(uap, shmid), cmd, 398 (cmd == IPC_SET || cmd == IPC_STAT) ? &shmbuf : NULL); 399 400 if (error == 0 && cmd == IPC_STAT) 401 error = copyout(&shmbuf, SCARG(uap, buf), sizeof(shmbuf)); 402 403 return (error); 404 } 405 406 int 407 shmctl1(struct proc *p, int shmid, int cmd, struct shmid_ds *shmbuf) 408 { 409 kauth_cred_t cred = p->p_cred; 410 struct shmid_ds *shmseg; 411 int error = 0; 412 413 shmseg = shm_find_segment_by_shmid(shmid); 414 if (shmseg == NULL) 415 return EINVAL; 416 switch (cmd) { 417 case IPC_STAT: 418 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) != 0) 419 return error; 420 memcpy(shmbuf, shmseg, sizeof(struct shmid_ds)); 421 break; 422 case IPC_SET: 423 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 424 return error; 425 shmseg->shm_perm.uid = shmbuf->shm_perm.uid; 426 shmseg->shm_perm.gid = shmbuf->shm_perm.gid; 427 shmseg->shm_perm.mode = 428 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 429 (shmbuf->shm_perm.mode & ACCESSPERMS); 430 shmseg->shm_ctime = time.tv_sec; 431 break; 432 case IPC_RMID: 433 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 434 return error; 435 shmseg->shm_perm._key = IPC_PRIVATE; 436 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 437 if (shmseg->shm_nattch <= 0) { 438 shm_deallocate_segment(shmseg); 439 shm_last_free = IPCID_TO_IX(shmid); 440 } 441 break; 442 case SHM_LOCK: 443 case SHM_UNLOCK: 444 default: 445 return EINVAL; 446 } 447 return 0; 448 } 449 450 static int 451 shmget_existing(struct proc *p, struct sys_shmget_args *uap, int mode, 452 int segnum, register_t *retval) 453 { 454 struct shmid_ds *shmseg; 455 kauth_cred_t cred = p->p_cred; 456 int error; 457 458 shmseg = &shmsegs[segnum]; 459 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 460 /* 461 * This segment is in the process of being allocated. Wait 462 * until it's done, and look the key up again (in case the 463 * allocation failed or it was freed). 464 */ 465 shmseg->shm_perm.mode |= SHMSEG_WANTED; 466 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 467 if (error) 468 return error; 469 return EAGAIN; 470 } 471 if ((error = ipcperm(cred, &shmseg->shm_perm, mode)) != 0) 472 return error; 473 if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz) 474 return EINVAL; 475 if ((SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL)) == 476 (IPC_CREAT | IPC_EXCL)) 477 return EEXIST; 478 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 479 return 0; 480 } 481 482 static int 483 shmget_allocate_segment(struct proc *p, struct sys_shmget_args *uap, int mode, 484 register_t *retval) 485 { 486 int i, segnum, shmid, size; 487 kauth_cred_t cred = p->p_cred; 488 struct shmid_ds *shmseg; 489 int error = 0; 490 491 if (SCARG(uap, size) < shminfo.shmmin || 492 SCARG(uap, size) > shminfo.shmmax) 493 return EINVAL; 494 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 495 return ENOSPC; 496 size = (SCARG(uap, size) + PGOFSET) & ~PGOFSET; 497 if (shm_committed + btoc(size) > shminfo.shmall) 498 return ENOMEM; 499 if (shm_last_free < 0) { 500 for (i = 0; i < shminfo.shmmni; i++) 501 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 502 break; 503 if (i == shminfo.shmmni) 504 panic("shmseg free count inconsistent"); 505 segnum = i; 506 } else { 507 segnum = shm_last_free; 508 shm_last_free = -1; 509 } 510 shmseg = &shmsegs[segnum]; 511 /* 512 * In case we sleep in malloc(), mark the segment present but deleted 513 * so that noone else tries to create the same key. 514 */ 515 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 516 shmseg->shm_perm._key = SCARG(uap, key); 517 shmseg->shm_perm._seq = (shmseg->shm_perm._seq + 1) & 0x7fff; 518 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 519 520 shmseg->_shm_internal = uao_create(size, 0); 521 522 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = kauth_cred_geteuid(cred); 523 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = kauth_cred_getegid(cred); 524 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 525 (mode & (ACCESSPERMS|SHMSEG_RMLINGER)) | SHMSEG_ALLOCATED; 526 shmseg->shm_segsz = SCARG(uap, size); 527 shmseg->shm_cpid = p->p_pid; 528 shmseg->shm_lpid = shmseg->shm_nattch = 0; 529 shmseg->shm_atime = shmseg->shm_dtime = 0; 530 shmseg->shm_ctime = time.tv_sec; 531 shm_committed += btoc(size); 532 shm_nused++; 533 534 *retval = shmid; 535 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 536 /* 537 * Somebody else wanted this key while we were asleep. Wake 538 * them up now. 539 */ 540 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 541 wakeup((caddr_t)shmseg); 542 } 543 return error; 544 } 545 546 int 547 sys_shmget(struct lwp *l, void *v, register_t *retval) 548 { 549 struct sys_shmget_args /* { 550 syscallarg(key_t) key; 551 syscallarg(int) size; 552 syscallarg(int) shmflg; 553 } */ *uap = v; 554 struct proc *p = l->l_proc; 555 int segnum, mode, error; 556 557 mode = SCARG(uap, shmflg) & ACCESSPERMS; 558 if (SCARG(uap, shmflg) & _SHM_RMLINGER) 559 mode |= SHMSEG_RMLINGER; 560 561 #ifdef SHMDEBUG 562 printf("shmget: key 0x%lx size 0x%x shmflg 0x%x mode 0x%x\n", 563 SCARG(uap, key), SCARG(uap, size), SCARG(uap, shmflg), mode); 564 #endif 565 566 if (SCARG(uap, key) != IPC_PRIVATE) { 567 again: 568 segnum = shm_find_segment_by_key(SCARG(uap, key)); 569 if (segnum >= 0) { 570 error = shmget_existing(p, uap, mode, segnum, retval); 571 if (error == EAGAIN) 572 goto again; 573 return error; 574 } 575 if ((SCARG(uap, shmflg) & IPC_CREAT) == 0) 576 return ENOENT; 577 } 578 return shmget_allocate_segment(p, uap, mode, retval); 579 } 580 581 void 582 shmfork(struct vmspace *vm1, struct vmspace *vm2) 583 { 584 struct shmmap_state *shmmap_s; 585 struct shmmap_entry *shmmap_se; 586 587 vm2->vm_shm = vm1->vm_shm; 588 589 if (vm1->vm_shm == NULL) 590 return; 591 592 #ifdef SHMDEBUG 593 printf("shmfork %p->%p\n", vm1, vm2); 594 #endif 595 596 shmmap_s = (struct shmmap_state *)vm1->vm_shm; 597 598 SLIST_FOREACH(shmmap_se, &shmmap_s->entries, next) 599 shmsegs[IPCID_TO_IX(shmmap_se->shmid)].shm_nattch++; 600 shmmap_s->nrefs++; 601 } 602 603 void 604 shmexit(struct vmspace *vm) 605 { 606 struct shmmap_state *shmmap_s; 607 struct shmmap_entry *shmmap_se; 608 609 shmmap_s = (struct shmmap_state *)vm->vm_shm; 610 if (shmmap_s == NULL) 611 return; 612 613 vm->vm_shm = NULL; 614 615 if (--shmmap_s->nrefs > 0) { 616 #ifdef SHMDEBUG 617 printf("shmexit: vm %p drop ref (%d entries), now used by %d\n", 618 vm, shmmap_s->nitems, shmmap_s->nrefs); 619 #endif 620 SLIST_FOREACH(shmmap_se, &shmmap_s->entries, next) 621 shmsegs[IPCID_TO_IX(shmmap_se->shmid)].shm_nattch--; 622 return; 623 } 624 625 #ifdef SHMDEBUG 626 printf("shmexit: vm %p cleanup (%d entries)\n", vm, shmmap_s->nitems); 627 #endif 628 while (!SLIST_EMPTY(&shmmap_s->entries)) { 629 shmmap_se = SLIST_FIRST(&shmmap_s->entries); 630 shm_delete_mapping(vm, shmmap_s, shmmap_se); 631 } 632 KASSERT(shmmap_s->nitems == 0); 633 free(shmmap_s, M_SHM); 634 } 635 636 void 637 shminit(void) 638 { 639 int i, sz; 640 vaddr_t v; 641 642 /* Allocate pageable memory for our structures */ 643 sz = shminfo.shmmni * sizeof(struct shmid_ds); 644 v = uvm_km_alloc(kernel_map, round_page(sz), 0, UVM_KMF_WIRED); 645 if (v == 0) 646 panic("sysv_shm: cannot allocate memory"); 647 shmsegs = (void *)v; 648 649 shminfo.shmmax *= PAGE_SIZE; 650 651 for (i = 0; i < shminfo.shmmni; i++) { 652 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 653 shmsegs[i].shm_perm._seq = 0; 654 } 655 shm_last_free = 0; 656 shm_nused = 0; 657 shm_committed = 0; 658 } 659
Indexes created Mon Sep 22 10:09:38 GMT 2025