sysv_shm.c revision 1.80
1/* $NetBSD: sysv_shm.c,v 1.80 2004/10/16 13:34:07 jdolecek 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 1.80 2004/10/16 13:34:07 jdolecek 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 91struct shmid_ds *shm_find_segment_by_shmid(int); 92 93static 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 113static int shm_last_free, shm_nused, shm_committed; 114struct shmid_ds *shmsegs; 115 116struct shmmap_entry { 117 SLIST_ENTRY(shmmap_entry) next; 118 vaddr_t va; 119 int shmid; 120}; 121 122static POOL_INIT(shmmap_entry_pool, sizeof(struct shmmap_entry), 0, 0, 0, 123 "shmmp", 0); 124 125struct shmmap_state { 126 unsigned int nitems; 127 unsigned int nrefs; 128 SLIST_HEAD(, shmmap_entry) entries; 129}; 130 131static int shm_find_segment_by_key(key_t); 132static void shm_deallocate_segment(struct shmid_ds *); 133static void shm_delete_mapping(struct vmspace *, struct shmmap_state *, 134 struct shmmap_entry *); 135static int shmget_existing(struct proc *, struct sys_shmget_args *, 136 int, int, register_t *); 137static int shmget_allocate_segment(struct proc *, struct sys_shmget_args *, 138 int, register_t *); 139static struct shmmap_state *shmmap_getprivate(struct proc *); 140static struct shmmap_entry *shm_find_mapping(struct shmmap_state *, vaddr_t); 141 142static int 143shm_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 155struct shmid_ds * 156shm_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 175static void 176shm_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 189static void 190shm_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 */ 227static struct shmmap_state * 228shmmap_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 261static struct shmmap_entry * 262shm_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 275int 276sys_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 311int 312sys_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 = VM_DEFAULT_ADDRESS(p->p_vmspace->vm_daddr, size); 362 } 363 uobj = shmseg->_shm_internal; 364 (*uobj->pgops->pgo_reference)(uobj); 365 error = uvm_map(&p->p_vmspace->vm_map, &attach_va, size, 366 uobj, 0, 0, 367 UVM_MAPFLAG(prot, prot, UVM_INH_SHARE, UVM_ADV_RANDOM, 0)); 368 if (error) { 369 (*uobj->pgops->pgo_detach)(uobj); 370 return error; 371 } 372 shmmap_se = pool_get(&shmmap_entry_pool, PR_WAITOK); 373 shmmap_se->va = attach_va; 374 shmmap_se->shmid = SCARG(uap, shmid); 375 shmmap_s = shmmap_getprivate(p); 376#ifdef SHMDEBUG 377 printf("shmat: vm %p: add %d @%lx\n", p->p_vmspace, shmid, attach_va); 378#endif 379 SLIST_INSERT_HEAD(&shmmap_s->entries, shmmap_se, next); 380 shmmap_s->nitems++; 381 shmseg->shm_lpid = p->p_pid; 382 shmseg->shm_atime = time.tv_sec; 383 shmseg->shm_nattch++; 384 385 retval[0] = attach_va; 386 return 0; 387} 388 389int 390sys___shmctl13(l, v, retval) 391 struct lwp *l; 392 void *v; 393 register_t *retval; 394{ 395 struct sys___shmctl13_args /* { 396 syscallarg(int) shmid; 397 syscallarg(int) cmd; 398 syscallarg(struct shmid_ds *) buf; 399 } */ *uap = v; 400 struct proc *p = l->l_proc; 401 struct shmid_ds shmbuf; 402 int cmd, error; 403 404 cmd = SCARG(uap, cmd); 405 406 if (cmd == IPC_SET) { 407 error = copyin(SCARG(uap, buf), &shmbuf, sizeof(shmbuf)); 408 if (error) 409 return (error); 410 } 411 412 error = shmctl1(p, SCARG(uap, shmid), cmd, 413 (cmd == IPC_SET || cmd == IPC_STAT) ? &shmbuf : NULL); 414 415 if (error == 0 && cmd == IPC_STAT) 416 error = copyout(&shmbuf, SCARG(uap, buf), sizeof(shmbuf)); 417 418 return (error); 419} 420 421int 422shmctl1(p, shmid, cmd, shmbuf) 423 struct proc *p; 424 int shmid; 425 int cmd; 426 struct shmid_ds *shmbuf; 427{ 428 struct ucred *cred = p->p_ucred; 429 struct shmid_ds *shmseg; 430 int error = 0; 431 432 shmseg = shm_find_segment_by_shmid(shmid); 433 if (shmseg == NULL) 434 return EINVAL; 435 switch (cmd) { 436 case IPC_STAT: 437 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) != 0) 438 return error; 439 memcpy(shmbuf, shmseg, sizeof(struct shmid_ds)); 440 break; 441 case IPC_SET: 442 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 443 return error; 444 shmseg->shm_perm.uid = shmbuf->shm_perm.uid; 445 shmseg->shm_perm.gid = shmbuf->shm_perm.gid; 446 shmseg->shm_perm.mode = 447 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 448 (shmbuf->shm_perm.mode & ACCESSPERMS); 449 shmseg->shm_ctime = time.tv_sec; 450 break; 451 case IPC_RMID: 452 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 453 return error; 454 shmseg->shm_perm._key = IPC_PRIVATE; 455 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 456 if (shmseg->shm_nattch <= 0) { 457 shm_deallocate_segment(shmseg); 458 shm_last_free = IPCID_TO_IX(shmid); 459 } 460 break; 461 case SHM_LOCK: 462 case SHM_UNLOCK: 463 default: 464 return EINVAL; 465 } 466 return 0; 467} 468 469static int 470shmget_existing(p, uap, mode, segnum, retval) 471 struct proc *p; 472 struct sys_shmget_args /* { 473 syscallarg(key_t) key; 474 syscallarg(size_t) size; 475 syscallarg(int) shmflg; 476 } */ *uap; 477 int mode; 478 int segnum; 479 register_t *retval; 480{ 481 struct shmid_ds *shmseg; 482 struct ucred *cred = p->p_ucred; 483 int error; 484 485 shmseg = &shmsegs[segnum]; 486 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 487 /* 488 * This segment is in the process of being allocated. Wait 489 * until it's done, and look the key up again (in case the 490 * allocation failed or it was freed). 491 */ 492 shmseg->shm_perm.mode |= SHMSEG_WANTED; 493 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 494 if (error) 495 return error; 496 return EAGAIN; 497 } 498 if ((error = ipcperm(cred, &shmseg->shm_perm, mode)) != 0) 499 return error; 500 if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz) 501 return EINVAL; 502 if ((SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL)) == 503 (IPC_CREAT | IPC_EXCL)) 504 return EEXIST; 505 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 506 return 0; 507} 508 509static int 510shmget_allocate_segment(p, uap, mode, retval) 511 struct proc *p; 512 struct sys_shmget_args /* { 513 syscallarg(key_t) key; 514 syscallarg(size_t) size; 515 syscallarg(int) shmflg; 516 } */ *uap; 517 int mode; 518 register_t *retval; 519{ 520 int i, segnum, shmid, size; 521 struct ucred *cred = p->p_ucred; 522 struct shmid_ds *shmseg; 523 int error = 0; 524 525 if (SCARG(uap, size) < shminfo.shmmin || 526 SCARG(uap, size) > shminfo.shmmax) 527 return EINVAL; 528 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 529 return ENOSPC; 530 size = (SCARG(uap, size) + PGOFSET) & ~PGOFSET; 531 if (shm_committed + btoc(size) > shminfo.shmall) 532 return ENOMEM; 533 if (shm_last_free < 0) { 534 for (i = 0; i < shminfo.shmmni; i++) 535 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 536 break; 537 if (i == shminfo.shmmni) 538 panic("shmseg free count inconsistent"); 539 segnum = i; 540 } else { 541 segnum = shm_last_free; 542 shm_last_free = -1; 543 } 544 shmseg = &shmsegs[segnum]; 545 /* 546 * In case we sleep in malloc(), mark the segment present but deleted 547 * so that noone else tries to create the same key. 548 */ 549 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 550 shmseg->shm_perm._key = SCARG(uap, key); 551 shmseg->shm_perm._seq = (shmseg->shm_perm._seq + 1) & 0x7fff; 552 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 553 554 shmseg->_shm_internal = uao_create(size, 0); 555 556 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 557 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 558 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 559 (mode & (ACCESSPERMS|SHMSEG_RMLINGER)) | SHMSEG_ALLOCATED; 560 shmseg->shm_segsz = SCARG(uap, size); 561 shmseg->shm_cpid = p->p_pid; 562 shmseg->shm_lpid = shmseg->shm_nattch = 0; 563 shmseg->shm_atime = shmseg->shm_dtime = 0; 564 shmseg->shm_ctime = time.tv_sec; 565 shm_committed += btoc(size); 566 shm_nused++; 567 568 *retval = shmid; 569 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 570 /* 571 * Somebody else wanted this key while we were asleep. Wake 572 * them up now. 573 */ 574 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 575 wakeup((caddr_t)shmseg); 576 } 577 return error; 578} 579 580int 581sys_shmget(l, v, retval) 582 struct lwp *l; 583 void *v; 584 register_t *retval; 585{ 586 struct sys_shmget_args /* { 587 syscallarg(key_t) key; 588 syscallarg(int) size; 589 syscallarg(int) shmflg; 590 } */ *uap = v; 591 struct proc *p = l->l_proc; 592 int segnum, mode, error; 593 594 mode = SCARG(uap, shmflg) & ACCESSPERMS; 595 if (SCARG(uap, shmflg) & _SHM_RMLINGER) 596 mode |= SHMSEG_RMLINGER; 597 598 if (SCARG(uap, key) != IPC_PRIVATE) { 599 again: 600 segnum = shm_find_segment_by_key(SCARG(uap, key)); 601 if (segnum >= 0) { 602 error = shmget_existing(p, uap, mode, segnum, retval); 603 if (error == EAGAIN) 604 goto again; 605 return error; 606 } 607 if ((SCARG(uap, shmflg) & IPC_CREAT) == 0) 608 return ENOENT; 609 } 610 return shmget_allocate_segment(p, uap, mode, retval); 611} 612 613void 614shmfork(vm1, vm2) 615 struct vmspace *vm1, *vm2; 616{ 617 struct shmmap_state *shmmap_s; 618 struct shmmap_entry *shmmap_se; 619 620 vm2->vm_shm = vm1->vm_shm; 621 622 if (vm1->vm_shm == NULL) 623 return; 624 625#ifdef SHMDEBUG 626 printf("shmfork %p->%p\n", vm1, vm2); 627#endif 628 629 shmmap_s = (struct shmmap_state *)vm1->vm_shm; 630 631 SLIST_FOREACH(shmmap_se, &shmmap_s->entries, next) 632 shmsegs[IPCID_TO_IX(shmmap_se->shmid)].shm_nattch++; 633 shmmap_s->nrefs++; 634} 635 636void 637shmexit(vm) 638 struct vmspace *vm; 639{ 640 struct shmmap_state *shmmap_s; 641 struct shmmap_entry *shmmap_se; 642 643 shmmap_s = (struct shmmap_state *)vm->vm_shm; 644 if (shmmap_s == NULL) 645 return; 646 647 vm->vm_shm = NULL; 648 649 if (--shmmap_s->nrefs > 0) { 650#ifdef SHMDEBUG 651 printf("shmexit: vm %p drop ref (%d entries), now used by %d\n", 652 vm, shmmap_s->nitems, shmmap_s->nrefs); 653#endif 654 SLIST_FOREACH(shmmap_se, &shmmap_s->entries, next) 655 shmsegs[IPCID_TO_IX(shmmap_se->shmid)].shm_nattch--; 656 return; 657 } 658 659#ifdef SHMDEBUG 660 printf("shmexit: vm %p cleanup (%d entries)\n", vm, shmmap_s->nitems); 661#endif 662 while (!SLIST_EMPTY(&shmmap_s->entries)) { 663 shmmap_se = SLIST_FIRST(&shmmap_s->entries); 664 shm_delete_mapping(vm, shmmap_s, shmmap_se); 665 } 666 KASSERT(shmmap_s->nitems == 0); 667 free(shmmap_s, M_SHM); 668} 669 670void 671shminit() 672{ 673 int i, sz; 674 vaddr_t v; 675 676 /* Allocate pageable memory for our structures */ 677 sz = shminfo.shmmni * sizeof(struct shmid_ds); 678 if ((v = uvm_km_alloc(kernel_map, round_page(sz))) == 0) 679 panic("sysv_shm: cannot allocate memory"); 680 shmsegs = (void *)v; 681 682 shminfo.shmmax *= PAGE_SIZE; 683 684 for (i = 0; i < shminfo.shmmni; i++) { 685 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 686 shmsegs[i].shm_perm._seq = 0; 687 } 688 shm_last_free = 0; 689 shm_nused = 0; 690 shm_committed = 0; 691} 692