sysv_shm.c revision 189283
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: head/sys/kern/sysv_shm.c 189283 2009-03-02 18:53:30Z kib $"); 64 65#include "opt_compat.h" 66#include "opt_sysvipc.h" 67#include "opt_mac.h" 68 69#include <sys/param.h> 70#include <sys/systm.h> 71#include <sys/kernel.h> 72#include <sys/lock.h> 73#include <sys/sysctl.h> 74#include <sys/shm.h> 75#include <sys/proc.h> 76#include <sys/malloc.h> 77#include <sys/mman.h> 78#include <sys/module.h> 79#include <sys/mutex.h> 80#include <sys/resourcevar.h> 81#include <sys/stat.h> 82#include <sys/syscall.h> 83#include <sys/syscallsubr.h> 84#include <sys/sysent.h> 85#include <sys/sysproto.h> 86#include <sys/jail.h> 87 88#include <security/mac/mac_framework.h> 89 90#include <vm/vm.h> 91#include <vm/vm_param.h> 92#include <vm/pmap.h> 93#include <vm/vm_object.h> 94#include <vm/vm_map.h> 95#include <vm/vm_page.h> 96#include <vm/vm_pager.h> 97 98static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments"); 99 100#if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43)) 101struct oshmctl_args; 102static int oshmctl(struct thread *td, struct oshmctl_args *uap); 103#endif 104 105static int shmget_allocate_segment(struct thread *td, 106 struct shmget_args *uap, int mode); 107static int shmget_existing(struct thread *td, struct shmget_args *uap, 108 int mode, int segnum); 109 110#if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43)) 111/* XXX casting to (sy_call_t *) is bogus, as usual. */ 112static sy_call_t *shmcalls[] = { 113 (sy_call_t *)shmat, (sy_call_t *)oshmctl, 114 (sy_call_t *)shmdt, (sy_call_t *)shmget, 115 (sy_call_t *)shmctl 116}; 117#endif 118 119#define SHMSEG_FREE 0x0200 120#define SHMSEG_REMOVED 0x0400 121#define SHMSEG_ALLOCATED 0x0800 122#define SHMSEG_WANTED 0x1000 123 124static int shm_last_free, shm_nused, shmalloced; 125size_t shm_committed; 126static struct shmid_kernel *shmsegs; 127 128struct shmmap_state { 129 vm_offset_t va; 130 int shmid; 131}; 132 133static void shm_deallocate_segment(struct shmid_kernel *); 134static int shm_find_segment_by_key(key_t); 135static struct shmid_kernel *shm_find_segment_by_shmid(int); 136static struct shmid_kernel *shm_find_segment_by_shmidx(int); 137static int shm_delete_mapping(struct vmspace *vm, struct shmmap_state *); 138static void shmrealloc(void); 139static void shminit(void); 140static int sysvshm_modload(struct module *, int, void *); 141static int shmunload(void); 142static void shmexit_myhook(struct vmspace *vm); 143static void shmfork_myhook(struct proc *p1, struct proc *p2); 144static int sysctl_shmsegs(SYSCTL_HANDLER_ARGS); 145 146/* 147 * Tuneable values. 148 */ 149#ifndef SHMMAXPGS 150#define SHMMAXPGS 8192 /* Note: sysv shared memory is swap backed. */ 151#endif 152#ifndef SHMMAX 153#define SHMMAX (SHMMAXPGS*PAGE_SIZE) 154#endif 155#ifndef SHMMIN 156#define SHMMIN 1 157#endif 158#ifndef SHMMNI 159#define SHMMNI 192 160#endif 161#ifndef SHMSEG 162#define SHMSEG 128 163#endif 164#ifndef SHMALL 165#define SHMALL (SHMMAXPGS) 166#endif 167 168struct shminfo shminfo = { 169 SHMMAX, 170 SHMMIN, 171 SHMMNI, 172 SHMSEG, 173 SHMALL 174}; 175 176static int shm_use_phys; 177static int shm_allow_removed; 178 179SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, 180 "Maximum shared memory segment size"); 181SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, 182 "Minimum shared memory segment size"); 183SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RDTUN, &shminfo.shmmni, 0, 184 "Number of shared memory identifiers"); 185SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RDTUN, &shminfo.shmseg, 0, 186 "Number of segments per process"); 187SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, 188 "Maximum number of pages available for shared memory"); 189SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, 190 &shm_use_phys, 0, "Enable/Disable locking of shared memory pages in core"); 191SYSCTL_INT(_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RW, 192 &shm_allow_removed, 0, 193 "Enable/Disable attachment to attached segments marked for removal"); 194SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLFLAG_RD, 195 NULL, 0, sysctl_shmsegs, "", 196 "Current number of shared memory segments allocated"); 197 198static int 199shm_find_segment_by_key(key) 200 key_t key; 201{ 202 int i; 203 204 for (i = 0; i < shmalloced; i++) 205 if ((shmsegs[i].u.shm_perm.mode & SHMSEG_ALLOCATED) && 206 shmsegs[i].u.shm_perm.key == key) 207 return (i); 208 return (-1); 209} 210 211static struct shmid_kernel * 212shm_find_segment_by_shmid(int shmid) 213{ 214 int segnum; 215 struct shmid_kernel *shmseg; 216 217 segnum = IPCID_TO_IX(shmid); 218 if (segnum < 0 || segnum >= shmalloced) 219 return (NULL); 220 shmseg = &shmsegs[segnum]; 221 if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 || 222 (!shm_allow_removed && 223 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0) || 224 shmseg->u.shm_perm.seq != IPCID_TO_SEQ(shmid)) 225 return (NULL); 226 return (shmseg); 227} 228 229static struct shmid_kernel * 230shm_find_segment_by_shmidx(int segnum) 231{ 232 struct shmid_kernel *shmseg; 233 234 if (segnum < 0 || segnum >= shmalloced) 235 return (NULL); 236 shmseg = &shmsegs[segnum]; 237 if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 || 238 (!shm_allow_removed && 239 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0)) 240 return (NULL); 241 return (shmseg); 242} 243 244static void 245shm_deallocate_segment(shmseg) 246 struct shmid_kernel *shmseg; 247{ 248 size_t size; 249 250 GIANT_REQUIRED; 251 252 vm_object_deallocate(shmseg->u.shm_internal); 253 shmseg->u.shm_internal = NULL; 254 size = round_page(shmseg->shm_bsegsz); 255 shm_committed -= btoc(size); 256 shm_nused--; 257 shmseg->u.shm_perm.mode = SHMSEG_FREE; 258#ifdef MAC 259 mac_sysvshm_cleanup(shmseg); 260#endif 261} 262 263static int 264shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s) 265{ 266 struct shmid_kernel *shmseg; 267 int segnum, result; 268 size_t size; 269 270 GIANT_REQUIRED; 271 272 segnum = IPCID_TO_IX(shmmap_s->shmid); 273 shmseg = &shmsegs[segnum]; 274 size = round_page(shmseg->shm_bsegsz); 275 result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size); 276 if (result != KERN_SUCCESS) 277 return (EINVAL); 278 shmmap_s->shmid = -1; 279 shmseg->u.shm_dtime = time_second; 280 if ((--shmseg->u.shm_nattch <= 0) && 281 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED)) { 282 shm_deallocate_segment(shmseg); 283 shm_last_free = segnum; 284 } 285 return (0); 286} 287 288#ifndef _SYS_SYSPROTO_H_ 289struct shmdt_args { 290 const void *shmaddr; 291}; 292#endif 293int 294shmdt(td, uap) 295 struct thread *td; 296 struct shmdt_args *uap; 297{ 298 struct proc *p = td->td_proc; 299 struct shmmap_state *shmmap_s; 300#ifdef MAC 301 struct shmid_kernel *shmsegptr; 302#endif 303 int i; 304 int error = 0; 305 306 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 307 return (ENOSYS); 308 mtx_lock(&Giant); 309 shmmap_s = p->p_vmspace->vm_shm; 310 if (shmmap_s == NULL) { 311 error = EINVAL; 312 goto done2; 313 } 314 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) { 315 if (shmmap_s->shmid != -1 && 316 shmmap_s->va == (vm_offset_t)uap->shmaddr) { 317 break; 318 } 319 } 320 if (i == shminfo.shmseg) { 321 error = EINVAL; 322 goto done2; 323 } 324#ifdef MAC 325 shmsegptr = &shmsegs[IPCID_TO_IX(shmmap_s->shmid)]; 326 error = mac_sysvshm_check_shmdt(td->td_ucred, shmsegptr); 327 if (error != 0) 328 goto done2; 329#endif 330 error = shm_delete_mapping(p->p_vmspace, shmmap_s); 331done2: 332 mtx_unlock(&Giant); 333 return (error); 334} 335 336#ifndef _SYS_SYSPROTO_H_ 337struct shmat_args { 338 int shmid; 339 const void *shmaddr; 340 int shmflg; 341}; 342#endif 343int 344kern_shmat(td, shmid, shmaddr, shmflg) 345 struct thread *td; 346 int shmid; 347 const void *shmaddr; 348 int shmflg; 349{ 350 struct proc *p = td->td_proc; 351 int i, flags; 352 struct shmid_kernel *shmseg; 353 struct shmmap_state *shmmap_s = NULL; 354 vm_offset_t attach_va; 355 vm_prot_t prot; 356 vm_size_t size; 357 int rv; 358 int error = 0; 359 360 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 361 return (ENOSYS); 362 mtx_lock(&Giant); 363 shmmap_s = p->p_vmspace->vm_shm; 364 if (shmmap_s == NULL) { 365 size = shminfo.shmseg * sizeof(struct shmmap_state); 366 shmmap_s = malloc(size, M_SHM, M_WAITOK); 367 for (i = 0; i < shminfo.shmseg; i++) 368 shmmap_s[i].shmid = -1; 369 p->p_vmspace->vm_shm = shmmap_s; 370 } 371 shmseg = shm_find_segment_by_shmid(shmid); 372 if (shmseg == NULL) { 373 error = EINVAL; 374 goto done2; 375 } 376 error = ipcperm(td, &shmseg->u.shm_perm, 377 (shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 378 if (error) 379 goto done2; 380#ifdef MAC 381 error = mac_sysvshm_check_shmat(td->td_ucred, shmseg, shmflg); 382 if (error != 0) 383 goto done2; 384#endif 385 for (i = 0; i < shminfo.shmseg; i++) { 386 if (shmmap_s->shmid == -1) 387 break; 388 shmmap_s++; 389 } 390 if (i >= shminfo.shmseg) { 391 error = EMFILE; 392 goto done2; 393 } 394 size = round_page(shmseg->shm_bsegsz); 395#ifdef VM_PROT_READ_IS_EXEC 396 prot = VM_PROT_READ | VM_PROT_EXECUTE; 397#else 398 prot = VM_PROT_READ; 399#endif 400 if ((shmflg & SHM_RDONLY) == 0) 401 prot |= VM_PROT_WRITE; 402 flags = MAP_ANON | MAP_SHARED; 403 if (shmaddr) { 404 flags |= MAP_FIXED; 405 if (shmflg & SHM_RND) { 406 attach_va = (vm_offset_t)shmaddr & ~(SHMLBA-1); 407 } else if (((vm_offset_t)shmaddr & (SHMLBA-1)) == 0) { 408 attach_va = (vm_offset_t)shmaddr; 409 } else { 410 error = EINVAL; 411 goto done2; 412 } 413 } else { 414 /* 415 * This is just a hint to vm_map_find() about where to 416 * put it. 417 */ 418 PROC_LOCK(p); 419 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_daddr + 420 lim_max(p, RLIMIT_DATA)); 421 PROC_UNLOCK(p); 422 } 423 424 vm_object_reference(shmseg->u.shm_internal); 425 rv = vm_map_find(&p->p_vmspace->vm_map, shmseg->u.shm_internal, 426 0, &attach_va, size, (flags & MAP_FIXED) ? VMFS_NO_SPACE : 427 VMFS_ANY_SPACE, prot, prot, 0); 428 if (rv != KERN_SUCCESS) { 429 vm_object_deallocate(shmseg->u.shm_internal); 430 error = ENOMEM; 431 goto done2; 432 } 433 vm_map_inherit(&p->p_vmspace->vm_map, 434 attach_va, attach_va + size, VM_INHERIT_SHARE); 435 436 shmmap_s->va = attach_va; 437 shmmap_s->shmid = shmid; 438 shmseg->u.shm_lpid = p->p_pid; 439 shmseg->u.shm_atime = time_second; 440 shmseg->u.shm_nattch++; 441 td->td_retval[0] = attach_va; 442done2: 443 mtx_unlock(&Giant); 444 return (error); 445} 446 447int 448shmat(td, uap) 449 struct thread *td; 450 struct shmat_args *uap; 451{ 452 return kern_shmat(td, uap->shmid, uap->shmaddr, uap->shmflg); 453} 454 455#if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43)) 456struct oshmid_ds { 457 struct ipc_perm shm_perm; /* operation perms */ 458 int shm_segsz; /* size of segment (bytes) */ 459 u_short shm_cpid; /* pid, creator */ 460 u_short shm_lpid; /* pid, last operation */ 461 short shm_nattch; /* no. of current attaches */ 462 time_t shm_atime; /* last attach time */ 463 time_t shm_dtime; /* last detach time */ 464 time_t shm_ctime; /* last change time */ 465 void *shm_handle; /* internal handle for shm segment */ 466}; 467 468struct oshmctl_args { 469 int shmid; 470 int cmd; 471 struct oshmid_ds *ubuf; 472}; 473static int 474oshmctl(td, uap) 475 struct thread *td; 476 struct oshmctl_args *uap; 477{ 478#ifdef COMPAT_43 479 int error = 0; 480 struct shmid_kernel *shmseg; 481 struct oshmid_ds outbuf; 482 483 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 484 return (ENOSYS); 485 mtx_lock(&Giant); 486 shmseg = shm_find_segment_by_shmid(uap->shmid); 487 if (shmseg == NULL) { 488 error = EINVAL; 489 goto done2; 490 } 491 switch (uap->cmd) { 492 case IPC_STAT: 493 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R); 494 if (error) 495 goto done2; 496#ifdef MAC 497 error = mac_sysvshm_check_shmctl(td->td_ucred, shmseg, uap->cmd); 498 if (error != 0) 499 goto done2; 500#endif 501 outbuf.shm_perm = shmseg->u.shm_perm; 502 outbuf.shm_segsz = shmseg->u.shm_segsz; 503 outbuf.shm_cpid = shmseg->u.shm_cpid; 504 outbuf.shm_lpid = shmseg->u.shm_lpid; 505 outbuf.shm_nattch = shmseg->u.shm_nattch; 506 outbuf.shm_atime = shmseg->u.shm_atime; 507 outbuf.shm_dtime = shmseg->u.shm_dtime; 508 outbuf.shm_ctime = shmseg->u.shm_ctime; 509 outbuf.shm_handle = shmseg->u.shm_internal; 510 error = copyout(&outbuf, uap->ubuf, sizeof(outbuf)); 511 if (error) 512 goto done2; 513 break; 514 default: 515 error = shmctl(td, (struct shmctl_args *)uap); 516 break; 517 } 518done2: 519 mtx_unlock(&Giant); 520 return (error); 521#else 522 return (EINVAL); 523#endif 524} 525#endif 526 527#ifndef _SYS_SYSPROTO_H_ 528struct shmctl_args { 529 int shmid; 530 int cmd; 531 struct shmid_ds *buf; 532}; 533#endif 534int 535kern_shmctl(td, shmid, cmd, buf, bufsz) 536 struct thread *td; 537 int shmid; 538 int cmd; 539 void *buf; 540 size_t *bufsz; 541{ 542 int error = 0; 543 struct shmid_kernel *shmseg; 544 545 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 546 return (ENOSYS); 547 548 mtx_lock(&Giant); 549 switch (cmd) { 550 /* 551 * It is possible that kern_shmctl is being called from the Linux ABI 552 * layer, in which case, we will need to implement IPC_INFO. It should 553 * be noted that other shmctl calls will be funneled through here for 554 * Linix binaries as well. 555 * 556 * NB: The Linux ABI layer will convert this data to structure(s) more 557 * consistent with the Linux ABI. 558 */ 559 case IPC_INFO: 560 memcpy(buf, &shminfo, sizeof(shminfo)); 561 if (bufsz) 562 *bufsz = sizeof(shminfo); 563 td->td_retval[0] = shmalloced; 564 goto done2; 565 case SHM_INFO: { 566 struct shm_info shm_info; 567 shm_info.used_ids = shm_nused; 568 shm_info.shm_rss = 0; /*XXX where to get from ? */ 569 shm_info.shm_tot = 0; /*XXX where to get from ? */ 570 shm_info.shm_swp = 0; /*XXX where to get from ? */ 571 shm_info.swap_attempts = 0; /*XXX where to get from ? */ 572 shm_info.swap_successes = 0; /*XXX where to get from ? */ 573 memcpy(buf, &shm_info, sizeof(shm_info)); 574 if (bufsz) 575 *bufsz = sizeof(shm_info); 576 td->td_retval[0] = shmalloced; 577 goto done2; 578 } 579 } 580 if (cmd == SHM_STAT) 581 shmseg = shm_find_segment_by_shmidx(shmid); 582 else 583 shmseg = shm_find_segment_by_shmid(shmid); 584 if (shmseg == NULL) { 585 error = EINVAL; 586 goto done2; 587 } 588#ifdef MAC 589 error = mac_sysvshm_check_shmctl(td->td_ucred, shmseg, cmd); 590 if (error != 0) 591 goto done2; 592#endif 593 switch (cmd) { 594 case SHM_STAT: 595 case IPC_STAT: 596 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R); 597 if (error) 598 goto done2; 599 memcpy(buf, &shmseg->u, sizeof(struct shmid_ds)); 600 if (bufsz) 601 *bufsz = sizeof(struct shmid_ds); 602 if (cmd == SHM_STAT) 603 td->td_retval[0] = IXSEQ_TO_IPCID(shmid, shmseg->u.shm_perm); 604 break; 605 case IPC_SET: { 606 struct shmid_ds *shmid; 607 608 shmid = (struct shmid_ds *)buf; 609 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M); 610 if (error) 611 goto done2; 612 shmseg->u.shm_perm.uid = shmid->shm_perm.uid; 613 shmseg->u.shm_perm.gid = shmid->shm_perm.gid; 614 shmseg->u.shm_perm.mode = 615 (shmseg->u.shm_perm.mode & ~ACCESSPERMS) | 616 (shmid->shm_perm.mode & ACCESSPERMS); 617 shmseg->u.shm_ctime = time_second; 618 break; 619 } 620 case IPC_RMID: 621 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M); 622 if (error) 623 goto done2; 624 shmseg->u.shm_perm.key = IPC_PRIVATE; 625 shmseg->u.shm_perm.mode |= SHMSEG_REMOVED; 626 if (shmseg->u.shm_nattch <= 0) { 627 shm_deallocate_segment(shmseg); 628 shm_last_free = IPCID_TO_IX(shmid); 629 } 630 break; 631#if 0 632 case SHM_LOCK: 633 case SHM_UNLOCK: 634#endif 635 default: 636 error = EINVAL; 637 break; 638 } 639done2: 640 mtx_unlock(&Giant); 641 return (error); 642} 643 644int 645shmctl(td, uap) 646 struct thread *td; 647 struct shmctl_args *uap; 648{ 649 int error = 0; 650 struct shmid_ds buf; 651 size_t bufsz; 652 653 /* 654 * The only reason IPC_INFO, SHM_INFO, SHM_STAT exists is to support 655 * Linux binaries. If we see the call come through the FreeBSD ABI, 656 * return an error back to the user since we do not to support this. 657 */ 658 if (uap->cmd == IPC_INFO || uap->cmd == SHM_INFO || 659 uap->cmd == SHM_STAT) 660 return (EINVAL); 661 662 /* IPC_SET needs to copyin the buffer before calling kern_shmctl */ 663 if (uap->cmd == IPC_SET) { 664 if ((error = copyin(uap->buf, &buf, sizeof(struct shmid_ds)))) 665 goto done; 666 } 667 668 error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz); 669 if (error) 670 goto done; 671 672 /* Cases in which we need to copyout */ 673 switch (uap->cmd) { 674 case IPC_STAT: 675 error = copyout(&buf, uap->buf, bufsz); 676 break; 677 } 678 679done: 680 if (error) { 681 /* Invalidate the return value */ 682 td->td_retval[0] = -1; 683 } 684 return (error); 685} 686 687 688#ifndef _SYS_SYSPROTO_H_ 689struct shmget_args { 690 key_t key; 691 size_t size; 692 int shmflg; 693}; 694#endif 695static int 696shmget_existing(td, uap, mode, segnum) 697 struct thread *td; 698 struct shmget_args *uap; 699 int mode; 700 int segnum; 701{ 702 struct shmid_kernel *shmseg; 703 int error; 704 705 shmseg = &shmsegs[segnum]; 706 if (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) { 707 /* 708 * This segment is in the process of being allocated. Wait 709 * until it's done, and look the key up again (in case the 710 * allocation failed or it was freed). 711 */ 712 shmseg->u.shm_perm.mode |= SHMSEG_WANTED; 713 error = tsleep(shmseg, PLOCK | PCATCH, "shmget", 0); 714 if (error) 715 return (error); 716 return (EAGAIN); 717 } 718 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) 719 return (EEXIST); 720#ifdef MAC 721 error = mac_sysvshm_check_shmget(td->td_ucred, shmseg, uap->shmflg); 722 if (error != 0) 723 return (error); 724#endif 725 if (uap->size && uap->size > shmseg->shm_bsegsz) 726 return (EINVAL); 727 td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm); 728 return (0); 729} 730 731static int 732shmget_allocate_segment(td, uap, mode) 733 struct thread *td; 734 struct shmget_args *uap; 735 int mode; 736{ 737 int i, segnum, shmid; 738 size_t size; 739 struct ucred *cred = td->td_ucred; 740 struct shmid_kernel *shmseg; 741 vm_object_t shm_object; 742 743 GIANT_REQUIRED; 744 745 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 746 return (EINVAL); 747 if (shm_nused >= shminfo.shmmni) /* Any shmids left? */ 748 return (ENOSPC); 749 size = round_page(uap->size); 750 if (shm_committed + btoc(size) > shminfo.shmall) 751 return (ENOMEM); 752 if (shm_last_free < 0) { 753 shmrealloc(); /* Maybe expand the shmsegs[] array. */ 754 for (i = 0; i < shmalloced; i++) 755 if (shmsegs[i].u.shm_perm.mode & SHMSEG_FREE) 756 break; 757 if (i == shmalloced) 758 return (ENOSPC); 759 segnum = i; 760 } else { 761 segnum = shm_last_free; 762 shm_last_free = -1; 763 } 764 shmseg = &shmsegs[segnum]; 765 /* 766 * In case we sleep in malloc(), mark the segment present but deleted 767 * so that noone else tries to create the same key. 768 */ 769 shmseg->u.shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 770 shmseg->u.shm_perm.key = uap->key; 771 shmseg->u.shm_perm.seq = (shmseg->u.shm_perm.seq + 1) & 0x7fff; 772 shmid = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm); 773 774 /* 775 * We make sure that we have allocated a pager before we need 776 * to. 777 */ 778 if (shm_use_phys) { 779 shm_object = 780 vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0); 781 } else { 782 shm_object = 783 vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0); 784 } 785 VM_OBJECT_LOCK(shm_object); 786 vm_object_clear_flag(shm_object, OBJ_ONEMAPPING); 787 vm_object_set_flag(shm_object, OBJ_NOSPLIT); 788 VM_OBJECT_UNLOCK(shm_object); 789 790 shmseg->u.shm_internal = shm_object; 791 shmseg->u.shm_perm.cuid = shmseg->u.shm_perm.uid = cred->cr_uid; 792 shmseg->u.shm_perm.cgid = shmseg->u.shm_perm.gid = cred->cr_gid; 793 shmseg->u.shm_perm.mode = (shmseg->u.shm_perm.mode & SHMSEG_WANTED) | 794 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 795 shmseg->u.shm_segsz = uap->size; 796 shmseg->shm_bsegsz = uap->size; 797 shmseg->u.shm_cpid = td->td_proc->p_pid; 798 shmseg->u.shm_lpid = shmseg->u.shm_nattch = 0; 799 shmseg->u.shm_atime = shmseg->u.shm_dtime = 0; 800#ifdef MAC 801 mac_sysvshm_create(cred, shmseg); 802#endif 803 shmseg->u.shm_ctime = time_second; 804 shm_committed += btoc(size); 805 shm_nused++; 806 if (shmseg->u.shm_perm.mode & SHMSEG_WANTED) { 807 /* 808 * Somebody else wanted this key while we were asleep. Wake 809 * them up now. 810 */ 811 shmseg->u.shm_perm.mode &= ~SHMSEG_WANTED; 812 wakeup(shmseg); 813 } 814 td->td_retval[0] = shmid; 815 return (0); 816} 817 818int 819shmget(td, uap) 820 struct thread *td; 821 struct shmget_args *uap; 822{ 823 int segnum, mode; 824 int error; 825 826 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 827 return (ENOSYS); 828 mtx_lock(&Giant); 829 mode = uap->shmflg & ACCESSPERMS; 830 if (uap->key != IPC_PRIVATE) { 831 again: 832 segnum = shm_find_segment_by_key(uap->key); 833 if (segnum >= 0) { 834 error = shmget_existing(td, uap, mode, segnum); 835 if (error == EAGAIN) 836 goto again; 837 goto done2; 838 } 839 if ((uap->shmflg & IPC_CREAT) == 0) { 840 error = ENOENT; 841 goto done2; 842 } 843 } 844 error = shmget_allocate_segment(td, uap, mode); 845done2: 846 mtx_unlock(&Giant); 847 return (error); 848} 849 850int 851shmsys(td, uap) 852 struct thread *td; 853 /* XXX actually varargs. */ 854 struct shmsys_args /* { 855 int which; 856 int a2; 857 int a3; 858 int a4; 859 } */ *uap; 860{ 861#if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43)) 862 int error; 863 864 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 865 return (ENOSYS); 866 if (uap->which < 0 || 867 uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0])) 868 return (EINVAL); 869 mtx_lock(&Giant); 870 error = (*shmcalls[uap->which])(td, &uap->a2); 871 mtx_unlock(&Giant); 872 return (error); 873#else 874 return (nosys(td, NULL)); 875#endif 876} 877 878static void 879shmfork_myhook(p1, p2) 880 struct proc *p1, *p2; 881{ 882 struct shmmap_state *shmmap_s; 883 size_t size; 884 int i; 885 886 mtx_lock(&Giant); 887 size = shminfo.shmseg * sizeof(struct shmmap_state); 888 shmmap_s = malloc(size, M_SHM, M_WAITOK); 889 bcopy(p1->p_vmspace->vm_shm, shmmap_s, size); 890 p2->p_vmspace->vm_shm = shmmap_s; 891 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 892 if (shmmap_s->shmid != -1) 893 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].u.shm_nattch++; 894 mtx_unlock(&Giant); 895} 896 897static void 898shmexit_myhook(struct vmspace *vm) 899{ 900 struct shmmap_state *base, *shm; 901 int i; 902 903 if ((base = vm->vm_shm) != NULL) { 904 vm->vm_shm = NULL; 905 mtx_lock(&Giant); 906 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) { 907 if (shm->shmid != -1) 908 shm_delete_mapping(vm, shm); 909 } 910 mtx_unlock(&Giant); 911 free(base, M_SHM); 912 } 913} 914 915static void 916shmrealloc(void) 917{ 918 int i; 919 struct shmid_kernel *newsegs; 920 921 if (shmalloced >= shminfo.shmmni) 922 return; 923 924 newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); 925 if (newsegs == NULL) 926 return; 927 for (i = 0; i < shmalloced; i++) 928 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0])); 929 for (; i < shminfo.shmmni; i++) { 930 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE; 931 shmsegs[i].u.shm_perm.seq = 0; 932#ifdef MAC 933 mac_sysvshm_init(&shmsegs[i]); 934#endif 935 } 936 free(shmsegs, M_SHM); 937 shmsegs = newsegs; 938 shmalloced = shminfo.shmmni; 939} 940 941static void 942shminit() 943{ 944 int i; 945 946 TUNABLE_ULONG_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall); 947 for (i = PAGE_SIZE; i > 0; i--) { 948 shminfo.shmmax = shminfo.shmall * i; 949 if (shminfo.shmmax >= shminfo.shmall) 950 break; 951 } 952 TUNABLE_ULONG_FETCH("kern.ipc.shmmin", &shminfo.shmmin); 953 TUNABLE_ULONG_FETCH("kern.ipc.shmmni", &shminfo.shmmni); 954 TUNABLE_ULONG_FETCH("kern.ipc.shmseg", &shminfo.shmseg); 955 TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys); 956 957 shmalloced = shminfo.shmmni; 958 shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); 959 if (shmsegs == NULL) 960 panic("cannot allocate initial memory for sysvshm"); 961 for (i = 0; i < shmalloced; i++) { 962 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE; 963 shmsegs[i].u.shm_perm.seq = 0; 964#ifdef MAC 965 mac_sysvshm_init(&shmsegs[i]); 966#endif 967 } 968 shm_last_free = 0; 969 shm_nused = 0; 970 shm_committed = 0; 971 shmexit_hook = &shmexit_myhook; 972 shmfork_hook = &shmfork_myhook; 973} 974 975static int 976shmunload() 977{ 978#ifdef MAC 979 int i; 980#endif 981 982 if (shm_nused > 0) 983 return (EBUSY); 984 985#ifdef MAC 986 for (i = 0; i < shmalloced; i++) 987 mac_sysvshm_destroy(&shmsegs[i]); 988#endif 989 free(shmsegs, M_SHM); 990 shmexit_hook = NULL; 991 shmfork_hook = NULL; 992 return (0); 993} 994 995static int 996sysctl_shmsegs(SYSCTL_HANDLER_ARGS) 997{ 998 999 return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0]))); 1000} 1001 1002static int 1003sysvshm_modload(struct module *module, int cmd, void *arg) 1004{ 1005 int error = 0; 1006 1007 switch (cmd) { 1008 case MOD_LOAD: 1009 shminit(); 1010 break; 1011 case MOD_UNLOAD: 1012 error = shmunload(); 1013 break; 1014 case MOD_SHUTDOWN: 1015 break; 1016 default: 1017 error = EINVAL; 1018 break; 1019 } 1020 return (error); 1021} 1022 1023static moduledata_t sysvshm_mod = { 1024 "sysvshm", 1025 &sysvshm_modload, 1026 NULL 1027}; 1028 1029SYSCALL_MODULE_HELPER(shmsys); 1030SYSCALL_MODULE_HELPER(shmat); 1031SYSCALL_MODULE_HELPER(shmctl); 1032SYSCALL_MODULE_HELPER(shmdt); 1033SYSCALL_MODULE_HELPER(shmget); 1034 1035DECLARE_MODULE(sysvshm, sysvshm_mod, 1036 SI_SUB_SYSV_SHM, SI_ORDER_FIRST); 1037MODULE_VERSION(sysvshm, 1); 1038