1 /* $NetBSD: sysv_shm.c,v 1.23 1994/07/04 23:25:12 glass Exp $ */ 2 /*- 3 * Copyright (c) 1994 Adam Glass and Charles Hannum. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by Adam Glass and Charles 16 * Hannum. 17 * 4. The names of the authors may not be used to endorse or promote products 18 * derived from this software without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR 21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 23 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, 24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 /*- 32 * Copyright (c) 2003-2005 McAfee, Inc. 33 * All rights reserved. 34 * 35 * This software was developed for the FreeBSD Project in part by McAfee 36 * Research, the Security Research Division of McAfee, Inc under DARPA/SPAWAR 37 * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research 38 * program. 39 * 40 * Redistribution and use in source and binary forms, with or without 41 * modification, are permitted provided that the following conditions 42 * are met: 43 * 1. Redistributions of source code must retain the above copyright 44 * notice, this list of conditions and the following disclaimer. 45 * 2. Redistributions in binary form must reproduce the above copyright 46 * notice, this list of conditions and the following disclaimer in the 47 * documentation and/or other materials provided with the distribution. 48 * 49 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 52 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 59 * SUCH DAMAGE. 60 */ 61 62 #include <sys/cdefs.h> 63 __FBSDID("$FreeBSD$"); 64 65 #include "opt_compat.h" 66 #include "opt_sysvipc.h" 67 68 #include <sys/param.h> 69 #include <sys/systm.h> 70 #include <sys/kernel.h> 71 #include <sys/lock.h> 72 #include <sys/sysctl.h> 73 #include <sys/shm.h> 74 #include <sys/proc.h> 75 #include <sys/malloc.h> 76 #include <sys/mman.h> 77 #include <sys/module.h> 78 #include <sys/mutex.h> 79 #include <sys/resourcevar.h> 80 #include <sys/stat.h> 81 #include <sys/syscall.h> 82 #include <sys/syscallsubr.h> 83 #include <sys/sysent.h> 84 #include <sys/sysproto.h> 85 #include <sys/jail.h> 86 87 #include <security/mac/mac_framework.h> 88 89 #include <vm/vm.h> 90 #include <vm/vm_param.h> 91 #include <vm/pmap.h> 92 #include <vm/vm_object.h> 93 #include <vm/vm_map.h> 94 #include <vm/vm_page.h> 95 #include <vm/vm_pager.h> 96 97 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments"); 98 99 static int shmget_allocate_segment(struct thread *td, 100 struct shmget_args *uap, int mode); 101 static int shmget_existing(struct thread *td, struct shmget_args *uap, 102 int mode, int segnum); 103 104 #define SHMSEG_FREE 0x0200 105 #define SHMSEG_REMOVED 0x0400 106 #define SHMSEG_ALLOCATED 0x0800 107 #define SHMSEG_WANTED 0x1000 108 109 static int shm_last_free, shm_nused, shmalloced; 110 vm_size_t shm_committed; 111 static struct shmid_kernel *shmsegs; 112 113 struct shmmap_state { 114 vm_offset_t va; 115 int shmid; 116 }; 117 118 static void shm_deallocate_segment(struct shmid_kernel *); 119 static int shm_find_segment_by_key(key_t); 120 static struct shmid_kernel *shm_find_segment_by_shmid(int); 121 static struct shmid_kernel *shm_find_segment_by_shmidx(int); 122 static int shm_delete_mapping(struct vmspace *vm, struct shmmap_state *); 123 static void shmrealloc(void); 124 static void shminit(void); 125 static int sysvshm_modload(struct module *, int, void *); 126 static int shmunload(void); 127 static void shmexit_myhook(struct vmspace *vm); 128 static void shmfork_myhook(struct proc *p1, struct proc *p2); 129 static int sysctl_shmsegs(SYSCTL_HANDLER_ARGS); 130 131 /* 132 * Tuneable values. 133 */ 134 #ifndef SHMMAXPGS 135 #define SHMMAXPGS 8192 /* Note: sysv shared memory is swap backed. */ 136 #endif 137 #ifndef SHMMAX 138 #define SHMMAX (SHMMAXPGS*PAGE_SIZE) 139 #endif 140 #ifndef SHMMIN 141 #define SHMMIN 1 142 #endif 143 #ifndef SHMMNI 144 #define SHMMNI 192 145 #endif 146 #ifndef SHMSEG 147 #define SHMSEG 128 148 #endif 149 #ifndef SHMALL 150 #define SHMALL (SHMMAXPGS) 151 #endif 152 153 struct shminfo shminfo = { 154 SHMMAX, 155 SHMMIN, 156 SHMMNI, 157 SHMSEG, 158 SHMALL 159 }; 160 161 static int shm_use_phys; 162 static int shm_allow_removed; 163 164 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, 165 "Maximum shared memory segment size"); 166 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, 167 "Minimum shared memory segment size"); 168 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RDTUN, &shminfo.shmmni, 0, 169 "Number of shared memory identifiers"); 170 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RDTUN, &shminfo.shmseg, 0, 171 "Number of segments per process"); 172 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, 173 "Maximum number of pages available for shared memory"); 174 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, 175 &shm_use_phys, 0, "Enable/Disable locking of shared memory pages in core"); 176 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RW, 177 &shm_allow_removed, 0, 178 "Enable/Disable attachment to attached segments marked for removal"); 179 SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLFLAG_RD, 180 NULL, 0, sysctl_shmsegs, "", 181 "Current number of shared memory segments allocated"); 182 183 static int 184 shm_find_segment_by_key(key) 185 key_t key; 186 { 187 int i; 188 189 for (i = 0; i < shmalloced; i++) 190 if ((shmsegs[i].u.shm_perm.mode & SHMSEG_ALLOCATED) && 191 shmsegs[i].u.shm_perm.key == key) 192 return (i); 193 return (-1); 194 } 195 196 static struct shmid_kernel * 197 shm_find_segment_by_shmid(int shmid) 198 { 199 int segnum; 200 struct shmid_kernel *shmseg; 201 202 segnum = IPCID_TO_IX(shmid); 203 if (segnum < 0 || segnum >= shmalloced) 204 return (NULL); 205 shmseg = &shmsegs[segnum]; 206 if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 || 207 (!shm_allow_removed && 208 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0) || 209 shmseg->u.shm_perm.seq != IPCID_TO_SEQ(shmid)) 210 return (NULL); 211 return (shmseg); 212 } 213 214 static struct shmid_kernel * 215 shm_find_segment_by_shmidx(int segnum) 216 { 217 struct shmid_kernel *shmseg; 218 219 if (segnum < 0 || segnum >= shmalloced) 220 return (NULL); 221 shmseg = &shmsegs[segnum]; 222 if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 || 223 (!shm_allow_removed && 224 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0)) 225 return (NULL); 226 return (shmseg); 227 } 228 229 static void 230 shm_deallocate_segment(shmseg) 231 struct shmid_kernel *shmseg; 232 { 233 vm_size_t size; 234 235 GIANT_REQUIRED; 236 237 vm_object_deallocate(shmseg->u.shm_internal); 238 shmseg->u.shm_internal = NULL; 239 size = round_page(shmseg->shm_bsegsz); 240 shm_committed -= btoc(size); 241 shm_nused--; 242 shmseg->u.shm_perm.mode = SHMSEG_FREE; 243 #ifdef MAC 244 mac_sysvshm_cleanup(shmseg); 245 #endif 246 } 247 248 static int 249 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s) 250 { 251 struct shmid_kernel *shmseg; 252 int segnum, result; 253 vm_size_t size; 254 255 GIANT_REQUIRED; 256 257 segnum = IPCID_TO_IX(shmmap_s->shmid); 258 shmseg = &shmsegs[segnum]; 259 size = round_page(shmseg->shm_bsegsz); 260 result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size); 261 if (result != KERN_SUCCESS) 262 return (EINVAL); 263 shmmap_s->shmid = -1; 264 shmseg->u.shm_dtime = time_second; 265 if ((--shmseg->u.shm_nattch <= 0) && 266 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED)) { 267 shm_deallocate_segment(shmseg); 268 shm_last_free = segnum; 269 } 270 return (0); 271 } 272 273 #ifndef _SYS_SYSPROTO_H_ 274 struct shmdt_args { 275 const void *shmaddr; 276 }; 277 #endif 278 int 279 shmdt(td, uap) 280 struct thread *td; 281 struct shmdt_args *uap; 282 { 283 struct proc *p = td->td_proc; 284 struct shmmap_state *shmmap_s; 285 #ifdef MAC 286 struct shmid_kernel *shmsegptr; 287 #endif 288 int i; 289 int error = 0; 290 291 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) 292 return (ENOSYS); 293 mtx_lock(&Giant); 294 shmmap_s = p->p_vmspace->vm_shm; 295 if (shmmap_s == NULL) { 296 error = EINVAL; 297 goto done2; 298 } 299 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) { 300 if (shmmap_s->shmid != -1 && 301 shmmap_s->va == (vm_offset_t)uap->shmaddr) { 302 break; 303 } 304 } 305 if (i == shminfo.shmseg) { 306 error = EINVAL; 307 goto done2; 308 } 309 #ifdef MAC 310 shmsegptr = &shmsegs[IPCID_TO_IX(shmmap_s->shmid)]; 311 error = mac_sysvshm_check_shmdt(td->td_ucred, shmsegptr); 312 if (error != 0) 313 goto done2; 314 #endif 315 error = shm_delete_mapping(p->p_vmspace, shmmap_s); 316 done2: 317 mtx_unlock(&Giant); 318 return (error); 319 } 320 321 #ifndef _SYS_SYSPROTO_H_ 322 struct shmat_args { 323 int shmid; 324 const void *shmaddr; 325 int shmflg; 326 }; 327 #endif 328 int 329 kern_shmat(td, shmid, shmaddr, shmflg) 330 struct thread *td; 331 int shmid; 332 const void *shmaddr; 333 int shmflg; 334 { 335 struct proc *p = td->td_proc; 336 int i, flags; 337 struct shmid_kernel *shmseg; 338 struct shmmap_state *shmmap_s = NULL; 339 vm_offset_t attach_va; 340 vm_prot_t prot; 341 vm_size_t size; 342 int rv; 343 int error = 0; 344 345 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) 346 return (ENOSYS); 347 mtx_lock(&Giant); 348 shmmap_s = p->p_vmspace->vm_shm; 349 if (shmmap_s == NULL) { 350 shmmap_s = malloc(shminfo.shmseg * sizeof(struct shmmap_state), 351 M_SHM, M_WAITOK); 352 for (i = 0; i < shminfo.shmseg; i++) 353 shmmap_s[i].shmid = -1; 354 p->p_vmspace->vm_shm = shmmap_s; 355 } 356 shmseg = shm_find_segment_by_shmid(shmid); 357 if (shmseg == NULL) { 358 error = EINVAL; 359 goto done2; 360 } 361 error = ipcperm(td, &shmseg->u.shm_perm, 362 (shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 363 if (error) 364 goto done2; 365 #ifdef MAC 366 error = mac_sysvshm_check_shmat(td->td_ucred, shmseg, shmflg); 367 if (error != 0) 368 goto done2; 369 #endif 370 for (i = 0; i < shminfo.shmseg; i++) { 371 if (shmmap_s->shmid == -1) 372 break; 373 shmmap_s++; 374 } 375 if (i >= shminfo.shmseg) { 376 error = EMFILE; 377 goto done2; 378 } 379 size = round_page(shmseg->shm_bsegsz); 380 prot = VM_PROT_READ; 381 if ((shmflg & SHM_RDONLY) == 0) 382 prot |= VM_PROT_WRITE; 383 flags = MAP_ANON | MAP_SHARED; 384 if (shmaddr) { 385 flags |= MAP_FIXED; 386 if (shmflg & SHM_RND) { 387 attach_va = (vm_offset_t)shmaddr & ~(SHMLBA-1); 388 } else if (((vm_offset_t)shmaddr & (SHMLBA-1)) == 0) { 389 attach_va = (vm_offset_t)shmaddr; 390 } else { 391 error = EINVAL; 392 goto done2; 393 } 394 } else { 395 /* 396 * This is just a hint to vm_map_find() about where to 397 * put it. 398 */ 399 PROC_LOCK(p); 400 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_daddr + 401 lim_max(p, RLIMIT_DATA)); 402 PROC_UNLOCK(p); 403 } 404 405 vm_object_reference(shmseg->u.shm_internal); 406 rv = vm_map_find(&p->p_vmspace->vm_map, shmseg->u.shm_internal, 407 0, &attach_va, size, (flags & MAP_FIXED) ? VMFS_NO_SPACE : 408 VMFS_ANY_SPACE, prot, prot, 0); 409 if (rv != KERN_SUCCESS) { 410 vm_object_deallocate(shmseg->u.shm_internal); 411 error = ENOMEM; 412 goto done2; 413 } 414 vm_map_inherit(&p->p_vmspace->vm_map, 415 attach_va, attach_va + size, VM_INHERIT_SHARE); 416 417 shmmap_s->va = attach_va; 418 shmmap_s->shmid = shmid; 419 shmseg->u.shm_lpid = p->p_pid; 420 shmseg->u.shm_atime = time_second; 421 shmseg->u.shm_nattch++; 422 td->td_retval[0] = attach_va; 423 done2: 424 mtx_unlock(&Giant); 425 return (error); 426 } 427 428 int 429 shmat(td, uap) 430 struct thread *td; 431 struct shmat_args *uap; 432 { 433 return kern_shmat(td, uap->shmid, uap->shmaddr, uap->shmflg); 434 } 435 436 int 437 kern_shmctl(td, shmid, cmd, buf, bufsz) 438 struct thread *td; 439 int shmid; 440 int cmd; 441 void *buf; 442 size_t *bufsz; 443 { 444 int error = 0; 445 struct shmid_kernel *shmseg; 446 447 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) 448 return (ENOSYS); 449 450 mtx_lock(&Giant); 451 switch (cmd) { 452 /* 453 * It is possible that kern_shmctl is being called from the Linux ABI 454 * layer, in which case, we will need to implement IPC_INFO. It should 455 * be noted that other shmctl calls will be funneled through here for 456 * Linix binaries as well. 457 * 458 * NB: The Linux ABI layer will convert this data to structure(s) more 459 * consistent with the Linux ABI. 460 */ 461 case IPC_INFO: 462 memcpy(buf, &shminfo, sizeof(shminfo)); 463 if (bufsz) 464 *bufsz = sizeof(shminfo); 465 td->td_retval[0] = shmalloced; 466 goto done2; 467 case SHM_INFO: { 468 struct shm_info shm_info; 469 shm_info.used_ids = shm_nused; 470 shm_info.shm_rss = 0; /*XXX where to get from ? */ 471 shm_info.shm_tot = 0; /*XXX where to get from ? */ 472 shm_info.shm_swp = 0; /*XXX where to get from ? */ 473 shm_info.swap_attempts = 0; /*XXX where to get from ? */ 474 shm_info.swap_successes = 0; /*XXX where to get from ? */ 475 memcpy(buf, &shm_info, sizeof(shm_info)); 476 if (bufsz) 477 *bufsz = sizeof(shm_info); 478 td->td_retval[0] = shmalloced; 479 goto done2; 480 } 481 } 482 if (cmd == SHM_STAT) 483 shmseg = shm_find_segment_by_shmidx(shmid); 484 else 485 shmseg = shm_find_segment_by_shmid(shmid); 486 if (shmseg == NULL) { 487 error = EINVAL; 488 goto done2; 489 } 490 #ifdef MAC 491 error = mac_sysvshm_check_shmctl(td->td_ucred, shmseg, cmd); 492 if (error != 0) 493 goto done2; 494 #endif 495 switch (cmd) { 496 case SHM_STAT: 497 case IPC_STAT: 498 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R); 499 if (error) 500 goto done2; 501 memcpy(buf, &shmseg->u, sizeof(struct shmid_ds)); 502 if (bufsz) 503 *bufsz = sizeof(struct shmid_ds); 504 if (cmd == SHM_STAT) 505 td->td_retval[0] = IXSEQ_TO_IPCID(shmid, shmseg->u.shm_perm); 506 break; 507 case IPC_SET: { 508 struct shmid_ds *shmid; 509 510 shmid = (struct shmid_ds *)buf; 511 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M); 512 if (error) 513 goto done2; 514 shmseg->u.shm_perm.uid = shmid->shm_perm.uid; 515 shmseg->u.shm_perm.gid = shmid->shm_perm.gid; 516 shmseg->u.shm_perm.mode = 517 (shmseg->u.shm_perm.mode & ~ACCESSPERMS) | 518 (shmid->shm_perm.mode & ACCESSPERMS); 519 shmseg->u.shm_ctime = time_second; 520 break; 521 } 522 case IPC_RMID: 523 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M); 524 if (error) 525 goto done2; 526 shmseg->u.shm_perm.key = IPC_PRIVATE; 527 shmseg->u.shm_perm.mode |= SHMSEG_REMOVED; 528 if (shmseg->u.shm_nattch <= 0) { 529 shm_deallocate_segment(shmseg); 530 shm_last_free = IPCID_TO_IX(shmid); 531 } 532 break; 533 #if 0 534 case SHM_LOCK: 535 case SHM_UNLOCK: 536 #endif 537 default: 538 error = EINVAL; 539 break; 540 } 541 done2: 542 mtx_unlock(&Giant); 543 return (error); 544 } 545 546 #ifndef _SYS_SYSPROTO_H_ 547 struct shmctl_args { 548 int shmid; 549 int cmd; 550 struct shmid_ds *buf; 551 }; 552 #endif 553 int 554 shmctl(td, uap) 555 struct thread *td; 556 struct shmctl_args *uap; 557 { 558 int error = 0; 559 struct shmid_ds buf; 560 size_t bufsz; 561 562 /* 563 * The only reason IPC_INFO, SHM_INFO, SHM_STAT exists is to support 564 * Linux binaries. If we see the call come through the FreeBSD ABI, 565 * return an error back to the user since we do not to support this. 566 */ 567 if (uap->cmd == IPC_INFO || uap->cmd == SHM_INFO || 568 uap->cmd == SHM_STAT) 569 return (EINVAL); 570 571 /* IPC_SET needs to copyin the buffer before calling kern_shmctl */ 572 if (uap->cmd == IPC_SET) { 573 if ((error = copyin(uap->buf, &buf, sizeof(struct shmid_ds)))) 574 goto done; 575 } 576 577 error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz); 578 if (error) 579 goto done; 580 581 /* Cases in which we need to copyout */ 582 switch (uap->cmd) { 583 case IPC_STAT: 584 error = copyout(&buf, uap->buf, bufsz); 585 break; 586 } 587 588 done: 589 if (error) { 590 /* Invalidate the return value */ 591 td->td_retval[0] = -1; 592 } 593 return (error); 594 } 595 596 597 static int 598 shmget_existing(td, uap, mode, segnum) 599 struct thread *td; 600 struct shmget_args *uap; 601 int mode; 602 int segnum; 603 { 604 struct shmid_kernel *shmseg; 605 int error; 606 607 shmseg = &shmsegs[segnum]; 608 if (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) { 609 /* 610 * This segment is in the process of being allocated. Wait 611 * until it's done, and look the key up again (in case the 612 * allocation failed or it was freed). 613 */ 614 shmseg->u.shm_perm.mode |= SHMSEG_WANTED; 615 error = tsleep(shmseg, PLOCK | PCATCH, "shmget", 0); 616 if (error) 617 return (error); 618 return (EAGAIN); 619 } 620 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) 621 return (EEXIST); 622 #ifdef MAC 623 error = mac_sysvshm_check_shmget(td->td_ucred, shmseg, uap->shmflg); 624 if (error != 0) 625 return (error); 626 #endif 627 if (uap->size != 0 && uap->size > shmseg->shm_bsegsz) 628 return (EINVAL); 629 td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm); 630 return (0); 631 } 632 633 static int 634 shmget_allocate_segment(td, uap, mode) 635 struct thread *td; 636 struct shmget_args *uap; 637 int mode; 638 { 639 int i, segnum, shmid; 640 size_t size; 641 struct ucred *cred = td->td_ucred; 642 struct shmid_kernel *shmseg; 643 vm_object_t shm_object; 644 645 GIANT_REQUIRED; 646 647 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 648 return (EINVAL); 649 if (shm_nused >= shminfo.shmmni) /* Any shmids left? */ 650 return (ENOSPC); 651 size = round_page(uap->size); 652 if (shm_committed + btoc(size) > shminfo.shmall) 653 return (ENOMEM); 654 if (shm_last_free < 0) { 655 shmrealloc(); /* Maybe expand the shmsegs[] array. */ 656 for (i = 0; i < shmalloced; i++) 657 if (shmsegs[i].u.shm_perm.mode & SHMSEG_FREE) 658 break; 659 if (i == shmalloced) 660 return (ENOSPC); 661 segnum = i; 662 } else { 663 segnum = shm_last_free; 664 shm_last_free = -1; 665 } 666 shmseg = &shmsegs[segnum]; 667 /* 668 * In case we sleep in malloc(), mark the segment present but deleted 669 * so that noone else tries to create the same key. 670 */ 671 shmseg->u.shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 672 shmseg->u.shm_perm.key = uap->key; 673 shmseg->u.shm_perm.seq = (shmseg->u.shm_perm.seq + 1) & 0x7fff; 674 shmid = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm); 675 676 /* 677 * We make sure that we have allocated a pager before we need 678 * to. 679 */ 680 shm_object = vm_pager_allocate(shm_use_phys ? OBJT_PHYS : OBJT_SWAP, 681 0, size, VM_PROT_DEFAULT, 0, cred); 682 if (shm_object == NULL) 683 return (ENOMEM); 684 VM_OBJECT_LOCK(shm_object); 685 vm_object_clear_flag(shm_object, OBJ_ONEMAPPING); 686 vm_object_set_flag(shm_object, OBJ_NOSPLIT); 687 VM_OBJECT_UNLOCK(shm_object); 688 689 shmseg->u.shm_internal = shm_object; 690 shmseg->u.shm_perm.cuid = shmseg->u.shm_perm.uid = cred->cr_uid; 691 shmseg->u.shm_perm.cgid = shmseg->u.shm_perm.gid = cred->cr_gid; 692 shmseg->u.shm_perm.mode = (shmseg->u.shm_perm.mode & SHMSEG_WANTED) | 693 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 694 shmseg->u.shm_segsz = uap->size; 695 shmseg->shm_bsegsz = uap->size; 696 shmseg->u.shm_cpid = td->td_proc->p_pid; 697 shmseg->u.shm_lpid = shmseg->u.shm_nattch = 0; 698 shmseg->u.shm_atime = shmseg->u.shm_dtime = 0; 699 #ifdef MAC 700 mac_sysvshm_create(cred, shmseg); 701 #endif 702 shmseg->u.shm_ctime = time_second; 703 shm_committed += btoc(size); 704 shm_nused++; 705 if (shmseg->u.shm_perm.mode & SHMSEG_WANTED) { 706 /* 707 * Somebody else wanted this key while we were asleep. Wake 708 * them up now. 709 */ 710 shmseg->u.shm_perm.mode &= ~SHMSEG_WANTED; 711 wakeup(shmseg); 712 } 713 td->td_retval[0] = shmid; 714 return (0); 715 } 716 717 #ifndef _SYS_SYSPROTO_H_ 718 struct shmget_args { 719 key_t key; 720 size_t size; 721 int shmflg; 722 }; 723 #endif 724 int 725 shmget(td, uap) 726 struct thread *td; 727 struct shmget_args *uap; 728 { 729 int segnum, mode; 730 int error; 731 732 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) 733 return (ENOSYS); 734 mtx_lock(&Giant); 735 mode = uap->shmflg & ACCESSPERMS; 736 if (uap->key != IPC_PRIVATE) { 737 again: 738 segnum = shm_find_segment_by_key(uap->key); 739 if (segnum >= 0) { 740 error = shmget_existing(td, uap, mode, segnum); 741 if (error == EAGAIN) 742 goto again; 743 goto done2; 744 } 745 if ((uap->shmflg & IPC_CREAT) == 0) { 746 error = ENOENT; 747 goto done2; 748 } 749 } 750 error = shmget_allocate_segment(td, uap, mode); 751 done2: 752 mtx_unlock(&Giant); 753 return (error); 754 } 755 756 static void 757 shmfork_myhook(p1, p2) 758 struct proc *p1, *p2; 759 { 760 struct shmmap_state *shmmap_s; 761 size_t size; 762 int i; 763 764 mtx_lock(&Giant); 765 size = shminfo.shmseg * sizeof(struct shmmap_state); 766 shmmap_s = malloc(size, M_SHM, M_WAITOK); 767 bcopy(p1->p_vmspace->vm_shm, shmmap_s, size); 768 p2->p_vmspace->vm_shm = shmmap_s; 769 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 770 if (shmmap_s->shmid != -1) 771 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].u.shm_nattch++; 772 mtx_unlock(&Giant); 773 } 774 775 static void 776 shmexit_myhook(struct vmspace *vm) 777 { 778 struct shmmap_state *base, *shm; 779 int i; 780 781 if ((base = vm->vm_shm) != NULL) { 782 vm->vm_shm = NULL; 783 mtx_lock(&Giant); 784 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) { 785 if (shm->shmid != -1) 786 shm_delete_mapping(vm, shm); 787 } 788 mtx_unlock(&Giant); 789 free(base, M_SHM); 790 } 791 } 792 793 static void 794 shmrealloc(void) 795 { 796 int i; 797 struct shmid_kernel *newsegs; 798 799 if (shmalloced >= shminfo.shmmni) 800 return; 801 802 newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); 803 if (newsegs == NULL) 804 return; 805 for (i = 0; i < shmalloced; i++) 806 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0])); 807 for (; i < shminfo.shmmni; i++) { 808 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE; 809 shmsegs[i].u.shm_perm.seq = 0; 810 #ifdef MAC 811 mac_sysvshm_init(&shmsegs[i]); 812 #endif 813 } 814 free(shmsegs, M_SHM); 815 shmsegs = newsegs; 816 shmalloced = shminfo.shmmni; 817 } 818 819 static void 820 shminit() 821 { 822 int i; 823 824 TUNABLE_ULONG_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall); 825 for (i = PAGE_SIZE; i > 0; i--) { 826 shminfo.shmmax = shminfo.shmall * i; 827 if (shminfo.shmmax >= shminfo.shmall) 828 break; 829 } 830 TUNABLE_ULONG_FETCH("kern.ipc.shmmin", &shminfo.shmmin); 831 TUNABLE_ULONG_FETCH("kern.ipc.shmmni", &shminfo.shmmni); 832 TUNABLE_ULONG_FETCH("kern.ipc.shmseg", &shminfo.shmseg); 833 TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys); 834 835 shmalloced = shminfo.shmmni; 836 shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); 837 if (shmsegs == NULL) 838 panic("cannot allocate initial memory for sysvshm"); 839 for (i = 0; i < shmalloced; i++) { 840 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE; 841 shmsegs[i].u.shm_perm.seq = 0; 842 #ifdef MAC 843 mac_sysvshm_init(&shmsegs[i]); 844 #endif 845 } 846 shm_last_free = 0; 847 shm_nused = 0; 848 shm_committed = 0; 849 shmexit_hook = &shmexit_myhook; 850 shmfork_hook = &shmfork_myhook; 851 } 852 853 static int 854 shmunload() 855 { 856 #ifdef MAC 857 int i; 858 #endif 859 860 if (shm_nused > 0) 861 return (EBUSY); 862 863 #ifdef MAC 864 for (i = 0; i < shmalloced; i++) 865 mac_sysvshm_destroy(&shmsegs[i]); 866 #endif 867 free(shmsegs, M_SHM); 868 shmexit_hook = NULL; 869 shmfork_hook = NULL; 870 return (0); 871 } 872 873 static int 874 sysctl_shmsegs(SYSCTL_HANDLER_ARGS) 875 { 876 877 return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0]))); 878 } 879 880 #if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43)) 881 struct oshmid_ds { 882 struct ipc_perm_old shm_perm; /* operation perms */ 883 int shm_segsz; /* size of segment (bytes) */ 884 u_short shm_cpid; /* pid, creator */ 885 u_short shm_lpid; /* pid, last operation */ 886 short shm_nattch; /* no. of current attaches */ 887 time_t shm_atime; /* last attach time */ 888 time_t shm_dtime; /* last detach time */ 889 time_t shm_ctime; /* last change time */ 890 void *shm_handle; /* internal handle for shm segment */ 891 }; 892 893 struct oshmctl_args { 894 int shmid; 895 int cmd; 896 struct oshmid_ds *ubuf; 897 }; 898 899 static int 900 oshmctl(td, uap) 901 struct thread *td; 902 struct oshmctl_args *uap; 903 { 904 #ifdef COMPAT_43 905 int error = 0; 906 struct shmid_kernel *shmseg; 907 struct oshmid_ds outbuf; 908 909 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) 910 return (ENOSYS); 911 mtx_lock(&Giant); 912 shmseg = shm_find_segment_by_shmid(uap->shmid); 913 if (shmseg == NULL) { 914 error = EINVAL; 915 goto done2; 916 } 917 switch (uap->cmd) { 918 case IPC_STAT: 919 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R); 920 if (error) 921 goto done2; 922 #ifdef MAC 923 error = mac_sysvshm_check_shmctl(td->td_ucred, shmseg, uap->cmd); 924 if (error != 0) 925 goto done2; 926 #endif 927 ipcperm_new2old(&shmseg->u.shm_perm, &outbuf.shm_perm); 928 outbuf.shm_segsz = shmseg->u.shm_segsz; 929 outbuf.shm_cpid = shmseg->u.shm_cpid; 930 outbuf.shm_lpid = shmseg->u.shm_lpid; 931 outbuf.shm_nattch = shmseg->u.shm_nattch; 932 outbuf.shm_atime = shmseg->u.shm_atime; 933 outbuf.shm_dtime = shmseg->u.shm_dtime; 934 outbuf.shm_ctime = shmseg->u.shm_ctime; 935 outbuf.shm_handle = shmseg->object; 936 error = copyout(&outbuf, uap->ubuf, sizeof(outbuf)); 937 if (error) 938 goto done2; 939 break; 940 default: 941 error = freebsd7_shmctl(td, (struct shmctl_args *)uap); 942 break; 943 } 944 done2: 945 mtx_unlock(&Giant); 946 return (error); 947 #else 948 return (EINVAL); 949 #endif 950 } 951 952 /* XXX casting to (sy_call_t *) is bogus, as usual. */ 953 static sy_call_t *shmcalls[] = { 954 (sy_call_t *)shmat, (sy_call_t *)oshmctl, 955 (sy_call_t *)shmdt, (sy_call_t *)shmget, 956 (sy_call_t *)shmctl 957 }; 958 959 int 960 shmsys(td, uap) 961 struct thread *td; 962 /* XXX actually varargs. */ 963 struct shmsys_args /* { 964 int which; 965 int a2; 966 int a3; 967 int a4; 968 } */ *uap; 969 { 970 int error; 971 972 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) 973 return (ENOSYS); 974 if (uap->which < 0 || 975 uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0])) 976 return (EINVAL); 977 mtx_lock(&Giant); 978 error = (*shmcalls[uap->which])(td, &uap->a2); 979 mtx_unlock(&Giant); 980 return (error); 981 } 982 983 SYSCALL_MODULE_HELPER(shmsys); 984 #endif /* i386 && (COMPAT_FREEBSD4 || COMPAT_43) */ 985 986 static int 987 sysvshm_modload(struct module *module, int cmd, void *arg) 988 { 989 int error = 0; 990 991 switch (cmd) { 992 case MOD_LOAD: 993 shminit(); 994 break; 995 case MOD_UNLOAD: 996 error = shmunload(); 997 break; 998 case MOD_SHUTDOWN: 999 break; 1000 default: 1001 error = EINVAL; 1002 break; 1003 } 1004 return (error); 1005 } 1006 1007 static moduledata_t sysvshm_mod = { 1008 "sysvshm", 1009 &sysvshm_modload, 1010 NULL 1011 }; 1012 1013 SYSCALL_MODULE_HELPER(shmat); 1014 SYSCALL_MODULE_HELPER(shmctl); 1015 SYSCALL_MODULE_HELPER(shmdt); 1016 SYSCALL_MODULE_HELPER(shmget); 1017 1018 DECLARE_MODULE(sysvshm, sysvshm_mod, SI_SUB_SYSV_SHM, SI_ORDER_FIRST); 1019 MODULE_VERSION(sysvshm, 1); 1020