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sys/kern/sysv_shm.c
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1 /* $NetBSD: sysv_shm.c,v 1.93 2006/11/28 20:35:16 ad 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 1.93 2006/11/28 20:35:16 ad Exp $"); 72 73 #define SYSVSHM 74 75 #include <sys/param.h> 76 #include <sys/kernel.h> 77 #include <sys/shm.h> 78 #include <sys/lock.h> 79 #include <sys/malloc.h> 80 #include <sys/mman.h> 81 #include <sys/stat.h> 82 #include <sys/sysctl.h> 83 #include <sys/mount.h> /* XXX for <sys/syscallargs.h> */ 84 #include <sys/sa.h> 85 #include <sys/syscallargs.h> 86 #include <sys/queue.h> 87 #include <sys/pool.h> 88 #include <sys/kauth.h> 89 90 #include <uvm/uvm_extern.h> 91 #include <uvm/uvm_object.h> 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 struct lock shm_lock; 117 static int shm_last_free, shm_committed, shm_use_phys; 118 119 static POOL_INIT(shmmap_entry_pool, sizeof(struct shmmap_entry), 0, 0, 0, 120 "shmmp", &pool_allocator_nointr); 121 122 struct shmmap_state { 123 unsigned int nitems; 124 unsigned int nrefs; 125 SLIST_HEAD(, shmmap_entry) entries; 126 }; 127 128 static int shm_find_segment_by_key(key_t); 129 static void shm_deallocate_segment(struct shmid_ds *); 130 static void shm_delete_mapping(struct vmspace *, struct shmmap_state *, 131 struct shmmap_entry *); 132 static int shmget_existing(struct lwp *, struct sys_shmget_args *, 133 int, int, register_t *); 134 static int shmget_allocate_segment(struct lwp *, struct sys_shmget_args *, 135 int, register_t *); 136 static struct shmmap_state *shmmap_getprivate(struct proc *); 137 static struct shmmap_entry *shm_find_mapping(struct shmmap_state *, vaddr_t); 138 static int shmrealloc(int); 139 140 static int 141 shm_find_segment_by_key(key_t key) 142 { 143 int i; 144 145 for (i = 0; i < shminfo.shmmni; i++) 146 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 147 shmsegs[i].shm_perm._key == key) 148 return i; 149 return -1; 150 } 151 152 static struct shmid_ds * 153 shm_find_segment_by_shmid(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(struct shmid_ds *shmseg) 173 { 174 struct uvm_object *uobj = shmseg->_shm_internal; 175 size_t size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 176 177 #ifdef SHMDEBUG 178 printf("shm freeing key 0x%lx seq 0x%x\n", 179 shmseg->shm_perm._key, shmseg->shm_perm._seq); 180 #endif 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(struct vmspace *vm, struct shmmap_state *shmmap_s, 191 struct shmmap_entry *shmmap_se) 192 { 193 struct shmid_ds *shmseg; 194 int segnum; 195 size_t size; 196 197 segnum = IPCID_TO_IX(shmmap_se->shmid); 198 #ifdef DEBUG 199 if (segnum < 0 || segnum >= shminfo.shmmni) 200 panic("shm_delete_mapping: vmspace %p state %p entry %p - " 201 "entry segment ID bad (%d)", 202 vm, shmmap_s, shmmap_se, segnum); 203 #endif 204 shmseg = &shmsegs[segnum]; 205 size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 206 uvm_deallocate(&vm->vm_map, shmmap_se->va, size); 207 SLIST_REMOVE(&shmmap_s->entries, shmmap_se, shmmap_entry, next); 208 shmmap_s->nitems--; 209 pool_put(&shmmap_entry_pool, shmmap_se); 210 shmseg->shm_dtime = time_second; 211 if ((--shmseg->shm_nattch <= 0) && 212 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 213 shm_deallocate_segment(shmseg); 214 shm_last_free = segnum; 215 } 216 } 217 218 /* 219 * Get a non-shared shm map for that vmspace. 220 * 3 cases: 221 * - no shm map present: create a fresh one 222 * - a shm map with refcount=1, just used by ourselves: fine 223 * - a shared shm map: copy to a fresh one and adjust refcounts 224 */ 225 static struct shmmap_state * 226 shmmap_getprivate(struct proc *p) 227 { 228 struct shmmap_state *oshmmap_s, *shmmap_s; 229 struct shmmap_entry *oshmmap_se, *shmmap_se; 230 231 oshmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 232 if (oshmmap_s && oshmmap_s->nrefs == 1) 233 return (oshmmap_s); 234 235 shmmap_s = malloc(sizeof(struct shmmap_state), M_SHM, M_WAITOK); 236 memset(shmmap_s, 0, sizeof(struct shmmap_state)); 237 shmmap_s->nrefs = 1; 238 SLIST_INIT(&shmmap_s->entries); 239 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 240 241 if (!oshmmap_s) 242 return (shmmap_s); 243 244 #ifdef SHMDEBUG 245 printf("shmmap_getprivate: vm %p split (%d entries), was used by %d\n", 246 p->p_vmspace, oshmmap_s->nitems, oshmmap_s->nrefs); 247 #endif 248 SLIST_FOREACH(oshmmap_se, &oshmmap_s->entries, next) { 249 shmmap_se = pool_get(&shmmap_entry_pool, PR_WAITOK); 250 shmmap_se->va = oshmmap_se->va; 251 shmmap_se->shmid = oshmmap_se->shmid; 252 SLIST_INSERT_HEAD(&shmmap_s->entries, shmmap_se, next); 253 } 254 shmmap_s->nitems = oshmmap_s->nitems; 255 oshmmap_s->nrefs--; 256 return (shmmap_s); 257 } 258 259 static struct shmmap_entry * 260 shm_find_mapping(struct shmmap_state *map, vaddr_t va) 261 { 262 struct shmmap_entry *shmmap_se; 263 264 SLIST_FOREACH(shmmap_se, &map->entries, next) { 265 if (shmmap_se->va == va) 266 return shmmap_se; 267 } 268 return 0; 269 } 270 271 int 272 sys_shmdt(struct lwp *l, void *v, register_t *retval) 273 { 274 struct sys_shmdt_args /* { 275 syscallarg(const void *) shmaddr; 276 } */ *uap = v; 277 struct proc *p = l->l_proc; 278 struct shmmap_state *shmmap_s, *shmmap_s1; 279 struct shmmap_entry *shmmap_se; 280 281 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 282 if (shmmap_s == NULL) 283 return EINVAL; 284 285 shmmap_se = shm_find_mapping(shmmap_s, (vaddr_t)SCARG(uap, shmaddr)); 286 if (!shmmap_se) 287 return EINVAL; 288 289 shmmap_s1 = shmmap_getprivate(p); 290 if (shmmap_s1 != shmmap_s) { 291 /* map has been copied, lookup entry in new map */ 292 shmmap_se = shm_find_mapping(shmmap_s1, 293 (vaddr_t)SCARG(uap, shmaddr)); 294 KASSERT(shmmap_se != NULL); 295 } 296 #ifdef SHMDEBUG 297 printf("shmdt: vm %p: remove %d @%lx\n", 298 p->p_vmspace, shmmap_se->shmid, shmmap_se->va); 299 #endif 300 shm_delete_mapping(p->p_vmspace, shmmap_s1, shmmap_se); 301 return 0; 302 } 303 304 int 305 sys_shmat(struct lwp *l, void *v, register_t *retval) 306 { 307 struct sys_shmat_args /* { 308 syscallarg(int) shmid; 309 syscallarg(const void *) shmaddr; 310 syscallarg(int) shmflg; 311 } */ *uap = v; 312 int error, flags; 313 struct proc *p = l->l_proc; 314 kauth_cred_t cred = l->l_cred; 315 struct shmid_ds *shmseg; 316 struct shmmap_state *shmmap_s; 317 struct uvm_object *uobj; 318 vaddr_t attach_va; 319 vm_prot_t prot; 320 vsize_t size; 321 struct shmmap_entry *shmmap_se; 322 323 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 324 if (shmseg == NULL) 325 return EINVAL; 326 error = ipcperm(cred, &shmseg->shm_perm, 327 (SCARG(uap, shmflg) & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 328 if (error) 329 return error; 330 331 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 332 if (shmmap_s && shmmap_s->nitems >= shminfo.shmseg) 333 return EMFILE; 334 335 size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 336 prot = VM_PROT_READ; 337 if ((SCARG(uap, shmflg) & SHM_RDONLY) == 0) 338 prot |= VM_PROT_WRITE; 339 flags = MAP_ANON | MAP_SHARED; 340 if (SCARG(uap, shmaddr)) { 341 flags |= MAP_FIXED; 342 if (SCARG(uap, shmflg) & SHM_RND) 343 attach_va = 344 (vaddr_t)SCARG(uap, shmaddr) & ~(SHMLBA-1); 345 else if (((vaddr_t)SCARG(uap, shmaddr) & (SHMLBA-1)) == 0) 346 attach_va = (vaddr_t)SCARG(uap, shmaddr); 347 else 348 return EINVAL; 349 } else { 350 /* This is just a hint to uvm_mmap() about where to put it. */ 351 attach_va = p->p_emul->e_vm_default_addr(p, 352 (vaddr_t)p->p_vmspace->vm_daddr, size); 353 } 354 uobj = shmseg->_shm_internal; 355 (*uobj->pgops->pgo_reference)(uobj); 356 error = uvm_map(&p->p_vmspace->vm_map, &attach_va, size, 357 uobj, 0, 0, 358 UVM_MAPFLAG(prot, prot, UVM_INH_SHARE, UVM_ADV_RANDOM, 0)); 359 if (error) 360 goto out; 361 /* Lock the memory */ 362 if (shm_use_phys || (shmseg->shm_perm.mode & SHMSEG_WIRED)) { 363 /* Wire the map */ 364 error = uvm_map_pageable(&p->p_vmspace->vm_map, attach_va, 365 attach_va + size, FALSE, 0); 366 if (error) { 367 if (error == EFAULT) 368 error = ENOMEM; 369 goto out; 370 } 371 } 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, shmmap_se->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_second; 384 shmseg->shm_nattch++; 385 386 retval[0] = attach_va; 387 return 0; 388 out: 389 (*uobj->pgops->pgo_detach)(uobj); 390 return error; 391 } 392 393 int 394 sys___shmctl13(struct lwp *l, void *v, 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 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(l, 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 } 420 421 int 422 shmctl1(struct lwp *l, int shmid, int cmd, struct shmid_ds *shmbuf) 423 { 424 kauth_cred_t cred = l->l_cred; 425 struct proc *p = l->l_proc; 426 struct shmid_ds *shmseg; 427 struct shmmap_entry *shmmap_se; 428 struct shmmap_state *shmmap_s; 429 int error = 0; 430 size_t size; 431 432 shmseg = shm_find_segment_by_shmid(shmid); 433 if (shmseg == NULL) 434 return EINVAL; 435 436 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_second; 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 if ((error = kauth_authorize_generic(cred, 465 KAUTH_GENERIC_ISSUSER, NULL)) != 0) 466 return error; 467 shmmap_s = shmmap_getprivate(p); 468 /* Find our shared memory address by shmid */ 469 SLIST_FOREACH(shmmap_se, &shmmap_s->entries, next) { 470 if (shmmap_se->shmid != shmid) 471 continue; 472 473 size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 474 475 if (cmd == SHM_LOCK && 476 !(shmseg->shm_perm.mode & SHMSEG_WIRED)) { 477 /* Wire the entire object */ 478 error = uobj_wirepages(shmseg->_shm_internal, 0, 479 round_page(shmseg->shm_segsz)); 480 if (error) 481 return EIO; 482 /* Wire the map */ 483 error = uvm_map_pageable(&p->p_vmspace->vm_map, 484 shmmap_se->va, shmmap_se->va + size, FALSE, 485 0); 486 if (error) { 487 uobj_unwirepages(shmseg->_shm_internal, 488 0, round_page(shmseg->shm_segsz)); 489 if (error == EFAULT) 490 error = ENOMEM; 491 return error; 492 } 493 /* Tag as wired */ 494 shmseg->shm_perm.mode |= SHMSEG_WIRED; 495 496 } else if (cmd == SHM_UNLOCK && 497 (shmseg->shm_perm.mode & SHMSEG_WIRED)) { 498 /* Unwire the object */ 499 uobj_unwirepages(shmseg->_shm_internal, 0, 500 round_page(shmseg->shm_segsz)); 501 error = uvm_map_pageable(&p->p_vmspace->vm_map, 502 shmmap_se->va, shmmap_se->va + size, TRUE, 503 0); 504 if (error) { 505 /* 506 * In fact, uvm_map_pageable could fail 507 * only if arguments are invalid, 508 * otherwise it should allways return 0. 509 */ 510 return EIO; 511 } 512 /* Tag as unwired */ 513 shmseg->shm_perm.mode &= ~SHMSEG_WIRED; 514 } 515 } 516 break; 517 default: 518 return EINVAL; 519 } 520 return 0; 521 } 522 523 static int 524 shmget_existing(struct lwp *l, struct sys_shmget_args *uap, int mode, 525 int segnum, register_t *retval) 526 { 527 struct shmid_ds *shmseg; 528 kauth_cred_t cred = l->l_cred; 529 int error; 530 531 shmseg = &shmsegs[segnum]; 532 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 533 /* 534 * This segment is in the process of being allocated. Wait 535 * until it's done, and look the key up again (in case the 536 * allocation failed or it was freed). 537 */ 538 shmseg->shm_perm.mode |= SHMSEG_WANTED; 539 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 540 if (error) 541 return error; 542 return EAGAIN; 543 } 544 if ((error = ipcperm(cred, &shmseg->shm_perm, mode)) != 0) 545 return error; 546 if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz) 547 return EINVAL; 548 if ((SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL)) == 549 (IPC_CREAT | IPC_EXCL)) 550 return EEXIST; 551 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 552 return 0; 553 } 554 555 static int 556 shmget_allocate_segment(struct lwp *l, struct sys_shmget_args *uap, int mode, 557 register_t *retval) 558 { 559 int i, segnum, shmid, size; 560 kauth_cred_t cred = l->l_cred; 561 struct shmid_ds *shmseg; 562 int error = 0; 563 564 if (SCARG(uap, size) < shminfo.shmmin || 565 SCARG(uap, size) > shminfo.shmmax) 566 return EINVAL; 567 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 568 return ENOSPC; 569 size = (SCARG(uap, size) + PGOFSET) & ~PGOFSET; 570 if (shm_committed + btoc(size) > shminfo.shmall) 571 return ENOMEM; 572 if (shm_last_free < 0) { 573 for (i = 0; i < shminfo.shmmni; i++) 574 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 575 break; 576 if (i == shminfo.shmmni) 577 panic("shmseg free count inconsistent"); 578 segnum = i; 579 } else { 580 segnum = shm_last_free; 581 shm_last_free = -1; 582 } 583 shmseg = &shmsegs[segnum]; 584 /* 585 * In case we sleep in malloc(), mark the segment present but deleted 586 * so that noone else tries to create the same key. 587 */ 588 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 589 shmseg->shm_perm._key = SCARG(uap, key); 590 shmseg->shm_perm._seq = (shmseg->shm_perm._seq + 1) & 0x7fff; 591 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 592 593 shmseg->_shm_internal = uao_create(size, 0); 594 595 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = kauth_cred_geteuid(cred); 596 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = kauth_cred_getegid(cred); 597 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 598 (mode & (ACCESSPERMS|SHMSEG_RMLINGER)) | SHMSEG_ALLOCATED; 599 shmseg->shm_segsz = SCARG(uap, size); 600 shmseg->shm_cpid = l->l_proc->p_pid; 601 shmseg->shm_lpid = shmseg->shm_nattch = 0; 602 shmseg->shm_atime = shmseg->shm_dtime = 0; 603 shmseg->shm_ctime = time_second; 604 shm_committed += btoc(size); 605 shm_nused++; 606 607 *retval = shmid; 608 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 609 /* 610 * Somebody else wanted this key while we were asleep. Wake 611 * them up now. 612 */ 613 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 614 wakeup((caddr_t)shmseg); 615 } 616 617 /* Lock the memory */ 618 if (shm_use_phys) { 619 /* Wire the entire object */ 620 error = uobj_wirepages(shmseg->_shm_internal, 0, 621 round_page(shmseg->shm_segsz)); 622 if (error) { 623 shm_deallocate_segment(shmseg); 624 } else { 625 /* Tag as wired */ 626 shmseg->shm_perm.mode |= SHMSEG_WIRED; 627 } 628 } 629 630 return error; 631 } 632 633 int 634 sys_shmget(struct lwp *l, void *v, register_t *retval) 635 { 636 struct sys_shmget_args /* { 637 syscallarg(key_t) key; 638 syscallarg(int) size; 639 syscallarg(int) shmflg; 640 } */ *uap = v; 641 int segnum, mode, error; 642 643 mode = SCARG(uap, shmflg) & ACCESSPERMS; 644 if (SCARG(uap, shmflg) & _SHM_RMLINGER) 645 mode |= SHMSEG_RMLINGER; 646 647 #ifdef SHMDEBUG 648 printf("shmget: key 0x%lx size 0x%x shmflg 0x%x mode 0x%x\n", 649 SCARG(uap, key), SCARG(uap, size), SCARG(uap, shmflg), mode); 650 #endif 651 652 if (SCARG(uap, key) != IPC_PRIVATE) { 653 again: 654 segnum = shm_find_segment_by_key(SCARG(uap, key)); 655 if (segnum >= 0) { 656 error = shmget_existing(l, uap, mode, segnum, retval); 657 if (error == EAGAIN) 658 goto again; 659 return error; 660 } 661 if ((SCARG(uap, shmflg) & IPC_CREAT) == 0) 662 return ENOENT; 663 } 664 return shmget_allocate_segment(l, uap, mode, retval); 665 } 666 667 void 668 shmfork(struct vmspace *vm1, struct vmspace *vm2) 669 { 670 struct shmmap_state *shmmap_s; 671 struct shmmap_entry *shmmap_se; 672 673 vm2->vm_shm = vm1->vm_shm; 674 675 if (vm1->vm_shm == NULL) 676 return; 677 678 #ifdef SHMDEBUG 679 printf("shmfork %p->%p\n", vm1, vm2); 680 #endif 681 682 shmmap_s = (struct shmmap_state *)vm1->vm_shm; 683 684 SLIST_FOREACH(shmmap_se, &shmmap_s->entries, next) 685 shmsegs[IPCID_TO_IX(shmmap_se->shmid)].shm_nattch++; 686 shmmap_s->nrefs++; 687 } 688 689 void 690 shmexit(struct vmspace *vm) 691 { 692 struct shmmap_state *shmmap_s; 693 struct shmmap_entry *shmmap_se; 694 695 shmmap_s = (struct shmmap_state *)vm->vm_shm; 696 if (shmmap_s == NULL) 697 return; 698 699 vm->vm_shm = NULL; 700 701 if (--shmmap_s->nrefs > 0) { 702 #ifdef SHMDEBUG 703 printf("shmexit: vm %p drop ref (%d entries), now used by %d\n", 704 vm, shmmap_s->nitems, shmmap_s->nrefs); 705 #endif 706 SLIST_FOREACH(shmmap_se, &shmmap_s->entries, next) 707 shmsegs[IPCID_TO_IX(shmmap_se->shmid)].shm_nattch--; 708 return; 709 } 710 711 #ifdef SHMDEBUG 712 printf("shmexit: vm %p cleanup (%d entries)\n", vm, shmmap_s->nitems); 713 #endif 714 while (!SLIST_EMPTY(&shmmap_s->entries)) { 715 shmmap_se = SLIST_FIRST(&shmmap_s->entries); 716 shm_delete_mapping(vm, shmmap_s, shmmap_se); 717 } 718 KASSERT(shmmap_s->nitems == 0); 719 free(shmmap_s, M_SHM); 720 } 721 722 static int 723 shmrealloc(int newshmni) 724 { 725 int i, sz; 726 vaddr_t v; 727 struct shmid_ds *newshmsegs; 728 729 /* XXX: Would be good to have a upper limit */ 730 if (newshmni < 1) 731 return EINVAL; 732 733 /* We can't reallocate lesser memory than we use */ 734 if (shm_nused > newshmni) 735 return EPERM; 736 737 /* Allocate new memory area */ 738 sz = newshmni * sizeof(struct shmid_ds); 739 v = uvm_km_alloc(kernel_map, round_page(sz), 0, UVM_KMF_WIRED); 740 if (v == 0) 741 return ENOMEM; 742 743 newshmsegs = (void *)v; 744 745 /* Copy all memory to the new area */ 746 for (i = 0; i < shm_nused; i++) 747 (void)memcpy(&newshmsegs[i], &shmsegs[i], 748 sizeof(newshmsegs[0])); 749 750 /* Mark as free all new segments, if there is any */ 751 for (; i < newshmni; i++) { 752 newshmsegs[i].shm_perm.mode = SHMSEG_FREE; 753 newshmsegs[i].shm_perm._seq = 0; 754 } 755 756 sz = shminfo.shmmni * sizeof(struct shmid_ds); 757 uvm_km_free(kernel_map, (vaddr_t)shmsegs, sz, UVM_KMF_WIRED); 758 shmsegs = newshmsegs; 759 760 return 0; 761 } 762 763 void 764 shminit(void) 765 { 766 int i, sz; 767 vaddr_t v; 768 769 lockinit(&shm_lock, PWAIT, "shmlk", 0, 0); 770 771 /* Allocate pageable memory for our structures */ 772 sz = shminfo.shmmni * sizeof(struct shmid_ds); 773 v = uvm_km_alloc(kernel_map, round_page(sz), 0, UVM_KMF_WIRED); 774 if (v == 0) 775 panic("sysv_shm: cannot allocate memory"); 776 shmsegs = (void *)v; 777 778 shminfo.shmmax *= PAGE_SIZE; 779 780 for (i = 0; i < shminfo.shmmni; i++) { 781 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 782 shmsegs[i].shm_perm._seq = 0; 783 } 784 shm_last_free = 0; 785 shm_nused = 0; 786 shm_committed = 0; 787 } 788 789 static int 790 sysctl_ipc_shmmni(SYSCTLFN_ARGS) 791 { 792 int newsize, error; 793 struct sysctlnode node; 794 node = *rnode; 795 node.sysctl_data = &newsize; 796 797 newsize = shminfo.shmmni; 798 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 799 if (error || newp == NULL) 800 return error; 801 802 lockmgr(&shm_lock, LK_EXCLUSIVE, NULL); 803 error = shmrealloc(newsize); 804 if (error == 0) 805 shminfo.shmmni = newsize; 806 lockmgr(&shm_lock, LK_RELEASE, NULL); 807 808 return error; 809 } 810 811 static int 812 sysctl_ipc_shmmaxpgs(SYSCTLFN_ARGS) 813 { 814 int newsize, error; 815 struct sysctlnode node; 816 node = *rnode; 817 node.sysctl_data = &newsize; 818 newsize = shminfo.shmall; 819 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 820 if (error || newp == NULL) 821 return error; 822 823 /* XXX: Would be good to have a upper limit */ 824 if (newsize < 1) 825 return EINVAL; 826 827 shminfo.shmall = newsize; 828 shminfo.shmmax = shminfo.shmall * PAGE_SIZE; 829 830 return 0; 831 } 832 833 SYSCTL_SETUP(sysctl_ipc_shm_setup, "sysctl kern.ipc subtree setup") 834 { 835 sysctl_createv(clog, 0, NULL, NULL, 836 CTLFLAG_PERMANENT, 837 CTLTYPE_NODE, "kern", NULL, 838 NULL, 0, NULL, 0, 839 CTL_KERN, CTL_EOL); 840 841 sysctl_createv(clog, 0, NULL, NULL, 842 CTLFLAG_PERMANENT, 843 CTLTYPE_NODE, "ipc", 844 SYSCTL_DESCR("SysV IPC options"), 845 NULL, 0, NULL, 0, 846 CTL_KERN, KERN_SYSVIPC, CTL_EOL); 847 848 sysctl_createv(clog, 0, NULL, NULL, 849 CTLFLAG_PERMANENT | CTLFLAG_READONLY, 850 CTLTYPE_INT, "shmmax", 851 SYSCTL_DESCR("Max shared memory segment size in bytes"), 852 NULL, 0, &shminfo.shmmax, 0, 853 CTL_KERN, KERN_SYSVIPC, KERN_SYSVIPC_SHMMAX, CTL_EOL); 854 855 sysctl_createv(clog, 0, NULL, NULL, 856 CTLFLAG_PERMANENT | CTLFLAG_READWRITE, 857 CTLTYPE_INT, "shmmni", 858 SYSCTL_DESCR("Max number of shared memory identifiers"), 859 sysctl_ipc_shmmni, 0, &shminfo.shmmni, 0, 860 CTL_KERN, KERN_SYSVIPC, KERN_SYSVIPC_SHMMNI, CTL_EOL); 861 862 sysctl_createv(clog, 0, NULL, NULL, 863 CTLFLAG_PERMANENT | CTLFLAG_READWRITE, 864 CTLTYPE_INT, "shmseg", 865 SYSCTL_DESCR("Max shared memory segments per process"), 866 NULL, 0, &shminfo.shmseg, 0, 867 CTL_KERN, KERN_SYSVIPC, KERN_SYSVIPC_SHMSEG, CTL_EOL); 868 869 sysctl_createv(clog, 0, NULL, NULL, 870 CTLFLAG_PERMANENT | CTLFLAG_READWRITE, 871 CTLTYPE_INT, "shmmaxpgs", 872 SYSCTL_DESCR("Max amount of shared memory in pages"), 873 sysctl_ipc_shmmaxpgs, 0, &shminfo.shmall, 0, 874 CTL_KERN, KERN_SYSVIPC, KERN_SYSVIPC_SHMMAXPGS, CTL_EOL); 875 876 sysctl_createv(clog, 0, NULL, NULL, 877 CTLFLAG_PERMANENT | CTLFLAG_READWRITE, 878 CTLTYPE_INT, "shm_use_phys", 879 SYSCTL_DESCR("Enable/disable locking of shared memory in " 880 "physical memory"), NULL, 0, &shm_use_phys, 0, 881 CTL_KERN, KERN_SYSVIPC, KERN_SYSVIPC_SHMUSEPHYS, CTL_EOL); 882 }
Cache object: 8ea7220355b3a3ce0403af5890ccee8c
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