sysv_shm.c revision 166835
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 166835 2007-02-19 22:56:10Z rwatson $"); 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, shm_committed, shmalloced; 125static struct shmid_kernel *shmsegs; 126 127struct shmmap_state { 128 vm_offset_t va; 129 int shmid; 130}; 131 132static void shm_deallocate_segment(struct shmid_kernel *); 133static int shm_find_segment_by_key(key_t); 134static struct shmid_kernel *shm_find_segment_by_shmid(int); 135static struct shmid_kernel *shm_find_segment_by_shmidx(int); 136static int shm_delete_mapping(struct vmspace *vm, struct shmmap_state *); 137static void shmrealloc(void); 138static void shminit(void); 139static int sysvshm_modload(struct module *, int, void *); 140static int shmunload(void); 141static void shmexit_myhook(struct vmspace *vm); 142static void shmfork_myhook(struct proc *p1, struct proc *p2); 143static int sysctl_shmsegs(SYSCTL_HANDLER_ARGS); 144 145/* 146 * Tuneable values. 147 */ 148#ifndef SHMMAXPGS 149#define SHMMAXPGS 8192 /* Note: sysv shared memory is swap backed. */ 150#endif 151#ifndef SHMMAX 152#define SHMMAX (SHMMAXPGS*PAGE_SIZE) 153#endif 154#ifndef SHMMIN 155#define SHMMIN 1 156#endif 157#ifndef SHMMNI 158#define SHMMNI 192 159#endif 160#ifndef SHMSEG 161#define SHMSEG 128 162#endif 163#ifndef SHMALL 164#define SHMALL (SHMMAXPGS) 165#endif 166 167struct shminfo shminfo = { 168 SHMMAX, 169 SHMMIN, 170 SHMMNI, 171 SHMSEG, 172 SHMALL 173}; 174 175static int shm_use_phys; 176static int shm_allow_removed; 177 178SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, 179 "Maximum shared memory segment size"); 180SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, 181 "Minimum shared memory segment size"); 182SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RDTUN, &shminfo.shmmni, 0, 183 "Number of shared memory identifiers"); 184SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RDTUN, &shminfo.shmseg, 0, 185 "Number of segments per process"); 186SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, 187 "Maximum number of pages available for shared memory"); 188SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, 189 &shm_use_phys, 0, "Enable/Disable locking of shared memory pages in core"); 190SYSCTL_INT(_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RW, 191 &shm_allow_removed, 0, 192 "Enable/Disable attachment to attached segments marked for removal"); 193SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLFLAG_RD, 194 NULL, 0, sysctl_shmsegs, "", 195 "Current number of shared memory segments allocated"); 196 197static int 198shm_find_segment_by_key(key) 199 key_t key; 200{ 201 int i; 202 203 for (i = 0; i < shmalloced; i++) 204 if ((shmsegs[i].u.shm_perm.mode & SHMSEG_ALLOCATED) && 205 shmsegs[i].u.shm_perm.key == key) 206 return (i); 207 return (-1); 208} 209 210static struct shmid_kernel * 211shm_find_segment_by_shmid(int shmid) 212{ 213 int segnum; 214 struct shmid_kernel *shmseg; 215 216 segnum = IPCID_TO_IX(shmid); 217 if (segnum < 0 || segnum >= shmalloced) 218 return (NULL); 219 shmseg = &shmsegs[segnum]; 220 if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 || 221 (!shm_allow_removed && 222 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0) || 223 shmseg->u.shm_perm.seq != IPCID_TO_SEQ(shmid)) 224 return (NULL); 225 return (shmseg); 226} 227 228static struct shmid_kernel * 229shm_find_segment_by_shmidx(int segnum) 230{ 231 struct shmid_kernel *shmseg; 232 233 if (segnum < 0 || segnum >= shmalloced) 234 return (NULL); 235 shmseg = &shmsegs[segnum]; 236 if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 || 237 (!shm_allow_removed && 238 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0)) 239 return (NULL); 240 return (shmseg); 241} 242 243static void 244shm_deallocate_segment(shmseg) 245 struct shmid_kernel *shmseg; 246{ 247 size_t size; 248 249 GIANT_REQUIRED; 250 251 vm_object_deallocate(shmseg->u.shm_internal); 252 shmseg->u.shm_internal = NULL; 253 size = round_page(shmseg->u.shm_segsz); 254 shm_committed -= btoc(size); 255 shm_nused--; 256 shmseg->u.shm_perm.mode = SHMSEG_FREE; 257#ifdef MAC 258 mac_cleanup_sysv_shm(shmseg); 259#endif 260} 261 262static int 263shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s) 264{ 265 struct shmid_kernel *shmseg; 266 int segnum, result; 267 size_t size; 268 269 GIANT_REQUIRED; 270 271 segnum = IPCID_TO_IX(shmmap_s->shmid); 272 shmseg = &shmsegs[segnum]; 273 size = round_page(shmseg->u.shm_segsz); 274 result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size); 275 if (result != KERN_SUCCESS) 276 return (EINVAL); 277 shmmap_s->shmid = -1; 278 shmseg->u.shm_dtime = time_second; 279 if ((--shmseg->u.shm_nattch <= 0) && 280 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED)) { 281 shm_deallocate_segment(shmseg); 282 shm_last_free = segnum; 283 } 284 return (0); 285} 286 287#ifndef _SYS_SYSPROTO_H_ 288struct shmdt_args { 289 const void *shmaddr; 290}; 291#endif 292 293/* 294 * MPSAFE 295 */ 296int 297shmdt(td, uap) 298 struct thread *td; 299 struct shmdt_args *uap; 300{ 301 struct proc *p = td->td_proc; 302 struct shmmap_state *shmmap_s; 303#ifdef MAC 304 struct shmid_kernel *shmsegptr; 305#endif 306 int i; 307 int error = 0; 308 309 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 310 return (ENOSYS); 311 mtx_lock(&Giant); 312 shmmap_s = p->p_vmspace->vm_shm; 313 if (shmmap_s == NULL) { 314 error = EINVAL; 315 goto done2; 316 } 317 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) { 318 if (shmmap_s->shmid != -1 && 319 shmmap_s->va == (vm_offset_t)uap->shmaddr) { 320 break; 321 } 322 } 323 if (i == shminfo.shmseg) { 324 error = EINVAL; 325 goto done2; 326 } 327#ifdef MAC 328 shmsegptr = &shmsegs[IPCID_TO_IX(shmmap_s->shmid)]; 329 error = mac_check_sysv_shmdt(td->td_ucred, shmsegptr); 330 if (error != 0) 331 goto done2; 332#endif 333 error = shm_delete_mapping(p->p_vmspace, shmmap_s); 334done2: 335 mtx_unlock(&Giant); 336 return (error); 337} 338 339#ifndef _SYS_SYSPROTO_H_ 340struct shmat_args { 341 int shmid; 342 const void *shmaddr; 343 int shmflg; 344}; 345#endif 346 347/* 348 * MPSAFE 349 */ 350int 351kern_shmat(td, shmid, shmaddr, shmflg) 352 struct thread *td; 353 int shmid; 354 const void *shmaddr; 355 int shmflg; 356{ 357 struct proc *p = td->td_proc; 358 int i, flags; 359 struct shmid_kernel *shmseg; 360 struct shmmap_state *shmmap_s = NULL; 361 vm_offset_t attach_va; 362 vm_prot_t prot; 363 vm_size_t size; 364 int rv; 365 int error = 0; 366 367 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 368 return (ENOSYS); 369 mtx_lock(&Giant); 370 shmmap_s = p->p_vmspace->vm_shm; 371 if (shmmap_s == NULL) { 372 size = shminfo.shmseg * sizeof(struct shmmap_state); 373 shmmap_s = malloc(size, M_SHM, M_WAITOK); 374 for (i = 0; i < shminfo.shmseg; i++) 375 shmmap_s[i].shmid = -1; 376 p->p_vmspace->vm_shm = shmmap_s; 377 } 378 shmseg = shm_find_segment_by_shmid(shmid); 379 if (shmseg == NULL) { 380 error = EINVAL; 381 goto done2; 382 } 383 error = ipcperm(td, &shmseg->u.shm_perm, 384 (shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 385 if (error) 386 goto done2; 387#ifdef MAC 388 error = mac_check_sysv_shmat(td->td_ucred, shmseg, shmflg); 389 if (error != 0) 390 goto done2; 391#endif 392 for (i = 0; i < shminfo.shmseg; i++) { 393 if (shmmap_s->shmid == -1) 394 break; 395 shmmap_s++; 396 } 397 if (i >= shminfo.shmseg) { 398 error = EMFILE; 399 goto done2; 400 } 401 size = round_page(shmseg->u.shm_segsz); 402#ifdef VM_PROT_READ_IS_EXEC 403 prot = VM_PROT_READ | VM_PROT_EXECUTE; 404#else 405 prot = VM_PROT_READ; 406#endif 407 if ((shmflg & SHM_RDONLY) == 0) 408 prot |= VM_PROT_WRITE; 409 flags = MAP_ANON | MAP_SHARED; 410 if (shmaddr) { 411 flags |= MAP_FIXED; 412 if (shmflg & SHM_RND) { 413 attach_va = (vm_offset_t)shmaddr & ~(SHMLBA-1); 414 } else if (((vm_offset_t)shmaddr & (SHMLBA-1)) == 0) { 415 attach_va = (vm_offset_t)shmaddr; 416 } else { 417 error = EINVAL; 418 goto done2; 419 } 420 } else { 421 /* 422 * This is just a hint to vm_map_find() about where to 423 * put it. 424 */ 425 PROC_LOCK(p); 426 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_daddr + 427 lim_max(p, RLIMIT_DATA)); 428 PROC_UNLOCK(p); 429 } 430 431 vm_object_reference(shmseg->u.shm_internal); 432 rv = vm_map_find(&p->p_vmspace->vm_map, shmseg->u.shm_internal, 433 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0); 434 if (rv != KERN_SUCCESS) { 435 vm_object_deallocate(shmseg->u.shm_internal); 436 error = ENOMEM; 437 goto done2; 438 } 439 vm_map_inherit(&p->p_vmspace->vm_map, 440 attach_va, attach_va + size, VM_INHERIT_SHARE); 441 442 shmmap_s->va = attach_va; 443 shmmap_s->shmid = shmid; 444 shmseg->u.shm_lpid = p->p_pid; 445 shmseg->u.shm_atime = time_second; 446 shmseg->u.shm_nattch++; 447 td->td_retval[0] = attach_va; 448done2: 449 mtx_unlock(&Giant); 450 return (error); 451} 452 453int 454shmat(td, uap) 455 struct thread *td; 456 struct shmat_args *uap; 457{ 458 return kern_shmat(td, uap->shmid, uap->shmaddr, uap->shmflg); 459} 460 461#if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43)) 462struct oshmid_ds { 463 struct ipc_perm shm_perm; /* operation perms */ 464 int shm_segsz; /* size of segment (bytes) */ 465 u_short shm_cpid; /* pid, creator */ 466 u_short shm_lpid; /* pid, last operation */ 467 short shm_nattch; /* no. of current attaches */ 468 time_t shm_atime; /* last attach time */ 469 time_t shm_dtime; /* last detach time */ 470 time_t shm_ctime; /* last change time */ 471 void *shm_handle; /* internal handle for shm segment */ 472}; 473 474struct oshmctl_args { 475 int shmid; 476 int cmd; 477 struct oshmid_ds *ubuf; 478}; 479 480/* 481 * MPSAFE 482 */ 483static int 484oshmctl(td, uap) 485 struct thread *td; 486 struct oshmctl_args *uap; 487{ 488#ifdef COMPAT_43 489 int error = 0; 490 struct shmid_kernel *shmseg; 491 struct oshmid_ds outbuf; 492 493 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 494 return (ENOSYS); 495 mtx_lock(&Giant); 496 shmseg = shm_find_segment_by_shmid(uap->shmid); 497 if (shmseg == NULL) { 498 error = EINVAL; 499 goto done2; 500 } 501 switch (uap->cmd) { 502 case IPC_STAT: 503 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R); 504 if (error) 505 goto done2; 506#ifdef MAC 507 error = mac_check_sysv_shmctl(td->td_ucred, shmseg, uap->cmd); 508 if (error != 0) 509 goto done2; 510#endif 511 outbuf.shm_perm = shmseg->u.shm_perm; 512 outbuf.shm_segsz = shmseg->u.shm_segsz; 513 outbuf.shm_cpid = shmseg->u.shm_cpid; 514 outbuf.shm_lpid = shmseg->u.shm_lpid; 515 outbuf.shm_nattch = shmseg->u.shm_nattch; 516 outbuf.shm_atime = shmseg->u.shm_atime; 517 outbuf.shm_dtime = shmseg->u.shm_dtime; 518 outbuf.shm_ctime = shmseg->u.shm_ctime; 519 outbuf.shm_handle = shmseg->u.shm_internal; 520 error = copyout(&outbuf, uap->ubuf, sizeof(outbuf)); 521 if (error) 522 goto done2; 523 break; 524 default: 525 error = shmctl(td, (struct shmctl_args *)uap); 526 break; 527 } 528done2: 529 mtx_unlock(&Giant); 530 return (error); 531#else 532 return (EINVAL); 533#endif 534} 535#endif 536 537#ifndef _SYS_SYSPROTO_H_ 538struct shmctl_args { 539 int shmid; 540 int cmd; 541 struct shmid_ds *buf; 542}; 543#endif 544 545/* 546 * MPSAFE 547 */ 548int 549kern_shmctl(td, shmid, cmd, buf, bufsz) 550 struct thread *td; 551 int shmid; 552 int cmd; 553 void *buf; 554 size_t *bufsz; 555{ 556 int error = 0; 557 struct shmid_kernel *shmseg; 558 559 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 560 return (ENOSYS); 561 562 mtx_lock(&Giant); 563 switch (cmd) { 564 case IPC_INFO: 565 memcpy(buf, &shminfo, sizeof(shminfo)); 566 if (bufsz) 567 *bufsz = sizeof(shminfo); 568 td->td_retval[0] = shmalloced; 569 goto done2; 570 case SHM_INFO: { 571 struct shm_info shm_info; 572 shm_info.used_ids = shm_nused; 573 shm_info.shm_rss = 0; /*XXX where to get from ? */ 574 shm_info.shm_tot = 0; /*XXX where to get from ? */ 575 shm_info.shm_swp = 0; /*XXX where to get from ? */ 576 shm_info.swap_attempts = 0; /*XXX where to get from ? */ 577 shm_info.swap_successes = 0; /*XXX where to get from ? */ 578 memcpy(buf, &shm_info, sizeof(shm_info)); 579 if (bufsz) 580 *bufsz = sizeof(shm_info); 581 td->td_retval[0] = shmalloced; 582 goto done2; 583 } 584 } 585 if (cmd == SHM_STAT) 586 shmseg = shm_find_segment_by_shmidx(shmid); 587 else 588 shmseg = shm_find_segment_by_shmid(shmid); 589 if (shmseg == NULL) { 590 error = EINVAL; 591 goto done2; 592 } 593#ifdef MAC 594 error = mac_check_sysv_shmctl(td->td_ucred, shmseg, cmd); 595 if (error != 0) 596 goto done2; 597#endif 598 switch (cmd) { 599 case SHM_STAT: 600 case IPC_STAT: 601 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R); 602 if (error) 603 goto done2; 604 memcpy(buf, &shmseg->u, sizeof(struct shmid_ds)); 605 if (bufsz) 606 *bufsz = sizeof(struct shmid_ds); 607 if (cmd == SHM_STAT) 608 td->td_retval[0] = IXSEQ_TO_IPCID(shmid, shmseg->u.shm_perm); 609 break; 610 case IPC_SET: { 611 struct shmid_ds *shmid; 612 613 shmid = (struct shmid_ds *)buf; 614 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M); 615 if (error) 616 goto done2; 617 shmseg->u.shm_perm.uid = shmid->shm_perm.uid; 618 shmseg->u.shm_perm.gid = shmid->shm_perm.gid; 619 shmseg->u.shm_perm.mode = 620 (shmseg->u.shm_perm.mode & ~ACCESSPERMS) | 621 (shmid->shm_perm.mode & ACCESSPERMS); 622 shmseg->u.shm_ctime = time_second; 623 break; 624 } 625 case IPC_RMID: 626 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M); 627 if (error) 628 goto done2; 629 shmseg->u.shm_perm.key = IPC_PRIVATE; 630 shmseg->u.shm_perm.mode |= SHMSEG_REMOVED; 631 if (shmseg->u.shm_nattch <= 0) { 632 shm_deallocate_segment(shmseg); 633 shm_last_free = IPCID_TO_IX(shmid); 634 } 635 break; 636#if 0 637 case SHM_LOCK: 638 case SHM_UNLOCK: 639#endif 640 default: 641 error = EINVAL; 642 break; 643 } 644done2: 645 mtx_unlock(&Giant); 646 return (error); 647} 648 649int 650shmctl(td, uap) 651 struct thread *td; 652 struct shmctl_args *uap; 653{ 654 int error = 0; 655 struct shmid_ds buf; 656 size_t bufsz; 657 658 /* IPC_SET needs to copyin the buffer before calling kern_shmctl */ 659 if (uap->cmd == IPC_SET) { 660 if ((error = copyin(uap->buf, &buf, sizeof(struct shmid_ds)))) 661 goto done; 662 } 663 664 error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz); 665 if (error) 666 goto done; 667 668 /* Cases in which we need to copyout */ 669 switch (uap->cmd) { 670 case IPC_INFO: 671 case SHM_INFO: 672 case SHM_STAT: 673 case IPC_STAT: 674 error = copyout(&buf, uap->buf, bufsz); 675 break; 676 } 677 678done: 679 if (error) { 680 /* Invalidate the return value */ 681 td->td_retval[0] = -1; 682 } 683 return (error); 684} 685 686 687#ifndef _SYS_SYSPROTO_H_ 688struct shmget_args { 689 key_t key; 690 size_t size; 691 int shmflg; 692}; 693#endif 694 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_check_sysv_shmget(td->td_ucred, shmseg, uap->shmflg); 722 if (error != 0) 723 return (error); 724#endif 725 if (uap->size && uap->size > shmseg->u.shm_segsz) 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, size; 738 struct ucred *cred = td->td_ucred; 739 struct shmid_kernel *shmseg; 740 vm_object_t shm_object; 741 742 GIANT_REQUIRED; 743 744 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 745 return (EINVAL); 746 if (shm_nused >= shminfo.shmmni) /* Any shmids left? */ 747 return (ENOSPC); 748 size = round_page(uap->size); 749 if (shm_committed + btoc(size) > shminfo.shmall) 750 return (ENOMEM); 751 if (shm_last_free < 0) { 752 shmrealloc(); /* Maybe expand the shmsegs[] array. */ 753 for (i = 0; i < shmalloced; i++) 754 if (shmsegs[i].u.shm_perm.mode & SHMSEG_FREE) 755 break; 756 if (i == shmalloced) 757 return (ENOSPC); 758 segnum = i; 759 } else { 760 segnum = shm_last_free; 761 shm_last_free = -1; 762 } 763 shmseg = &shmsegs[segnum]; 764 /* 765 * In case we sleep in malloc(), mark the segment present but deleted 766 * so that noone else tries to create the same key. 767 */ 768 shmseg->u.shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 769 shmseg->u.shm_perm.key = uap->key; 770 shmseg->u.shm_perm.seq = (shmseg->u.shm_perm.seq + 1) & 0x7fff; 771 shmid = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm); 772 773 /* 774 * We make sure that we have allocated a pager before we need 775 * to. 776 */ 777 if (shm_use_phys) { 778 shm_object = 779 vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0); 780 } else { 781 shm_object = 782 vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0); 783 } 784 VM_OBJECT_LOCK(shm_object); 785 vm_object_clear_flag(shm_object, OBJ_ONEMAPPING); 786 vm_object_set_flag(shm_object, OBJ_NOSPLIT); 787 VM_OBJECT_UNLOCK(shm_object); 788 789 shmseg->u.shm_internal = shm_object; 790 shmseg->u.shm_perm.cuid = shmseg->u.shm_perm.uid = cred->cr_uid; 791 shmseg->u.shm_perm.cgid = shmseg->u.shm_perm.gid = cred->cr_gid; 792 shmseg->u.shm_perm.mode = (shmseg->u.shm_perm.mode & SHMSEG_WANTED) | 793 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 794 shmseg->u.shm_segsz = uap->size; 795 shmseg->u.shm_cpid = td->td_proc->p_pid; 796 shmseg->u.shm_lpid = shmseg->u.shm_nattch = 0; 797 shmseg->u.shm_atime = shmseg->u.shm_dtime = 0; 798#ifdef MAC 799 mac_create_sysv_shm(cred, shmseg); 800#endif 801 shmseg->u.shm_ctime = time_second; 802 shm_committed += btoc(size); 803 shm_nused++; 804 if (shmseg->u.shm_perm.mode & SHMSEG_WANTED) { 805 /* 806 * Somebody else wanted this key while we were asleep. Wake 807 * them up now. 808 */ 809 shmseg->u.shm_perm.mode &= ~SHMSEG_WANTED; 810 wakeup(shmseg); 811 } 812 td->td_retval[0] = shmid; 813 return (0); 814} 815 816/* 817 * MPSAFE 818 */ 819int 820shmget(td, uap) 821 struct thread *td; 822 struct shmget_args *uap; 823{ 824 int segnum, mode; 825 int error; 826 827 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 828 return (ENOSYS); 829 mtx_lock(&Giant); 830 mode = uap->shmflg & ACCESSPERMS; 831 if (uap->key != IPC_PRIVATE) { 832 again: 833 segnum = shm_find_segment_by_key(uap->key); 834 if (segnum >= 0) { 835 error = shmget_existing(td, uap, mode, segnum); 836 if (error == EAGAIN) 837 goto again; 838 goto done2; 839 } 840 if ((uap->shmflg & IPC_CREAT) == 0) { 841 error = ENOENT; 842 goto done2; 843 } 844 } 845 error = shmget_allocate_segment(td, uap, mode); 846done2: 847 mtx_unlock(&Giant); 848 return (error); 849} 850 851/* 852 * MPSAFE 853 */ 854int 855shmsys(td, uap) 856 struct thread *td; 857 /* XXX actually varargs. */ 858 struct shmsys_args /* { 859 int which; 860 int a2; 861 int a3; 862 int a4; 863 } */ *uap; 864{ 865#if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43)) 866 int error; 867 868 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 869 return (ENOSYS); 870 if (uap->which < 0 || 871 uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0])) 872 return (EINVAL); 873 mtx_lock(&Giant); 874 error = (*shmcalls[uap->which])(td, &uap->a2); 875 mtx_unlock(&Giant); 876 return (error); 877#else 878 return (nosys(td, NULL)); 879#endif 880} 881 882static void 883shmfork_myhook(p1, p2) 884 struct proc *p1, *p2; 885{ 886 struct shmmap_state *shmmap_s; 887 size_t size; 888 int i; 889 890 mtx_lock(&Giant); 891 size = shminfo.shmseg * sizeof(struct shmmap_state); 892 shmmap_s = malloc(size, M_SHM, M_WAITOK); 893 bcopy(p1->p_vmspace->vm_shm, shmmap_s, size); 894 p2->p_vmspace->vm_shm = shmmap_s; 895 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 896 if (shmmap_s->shmid != -1) 897 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].u.shm_nattch++; 898 mtx_unlock(&Giant); 899} 900 901static void 902shmexit_myhook(struct vmspace *vm) 903{ 904 struct shmmap_state *base, *shm; 905 int i; 906 907 if ((base = vm->vm_shm) != NULL) { 908 vm->vm_shm = NULL; 909 mtx_lock(&Giant); 910 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) { 911 if (shm->shmid != -1) 912 shm_delete_mapping(vm, shm); 913 } 914 mtx_unlock(&Giant); 915 free(base, M_SHM); 916 } 917} 918 919static void 920shmrealloc(void) 921{ 922 int i; 923 struct shmid_kernel *newsegs; 924 925 if (shmalloced >= shminfo.shmmni) 926 return; 927 928 newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); 929 if (newsegs == NULL) 930 return; 931 for (i = 0; i < shmalloced; i++) 932 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0])); 933 for (; i < shminfo.shmmni; i++) { 934 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE; 935 shmsegs[i].u.shm_perm.seq = 0; 936#ifdef MAC 937 mac_init_sysv_shm(&shmsegs[i]); 938#endif 939 } 940 free(shmsegs, M_SHM); 941 shmsegs = newsegs; 942 shmalloced = shminfo.shmmni; 943} 944 945static void 946shminit() 947{ 948 int i; 949 950 TUNABLE_ULONG_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall); 951 for (i = PAGE_SIZE; i > 0; i--) { 952 shminfo.shmmax = shminfo.shmall * i; 953 if (shminfo.shmmax >= shminfo.shmall) 954 break; 955 } 956 TUNABLE_ULONG_FETCH("kern.ipc.shmmin", &shminfo.shmmin); 957 TUNABLE_ULONG_FETCH("kern.ipc.shmmni", &shminfo.shmmni); 958 TUNABLE_ULONG_FETCH("kern.ipc.shmseg", &shminfo.shmseg); 959 TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys); 960 961 shmalloced = shminfo.shmmni; 962 shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); 963 if (shmsegs == NULL) 964 panic("cannot allocate initial memory for sysvshm"); 965 for (i = 0; i < shmalloced; i++) { 966 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE; 967 shmsegs[i].u.shm_perm.seq = 0; 968#ifdef MAC 969 mac_init_sysv_shm(&shmsegs[i]); 970#endif 971 } 972 shm_last_free = 0; 973 shm_nused = 0; 974 shm_committed = 0; 975 shmexit_hook = &shmexit_myhook; 976 shmfork_hook = &shmfork_myhook; 977} 978 979static int 980shmunload() 981{ 982#ifdef MAC 983 int i; 984#endif 985 986 if (shm_nused > 0) 987 return (EBUSY); 988 989#ifdef MAC 990 for (i = 0; i < shmalloced; i++) 991 mac_destroy_sysv_shm(&shmsegs[i]); 992#endif 993 free(shmsegs, M_SHM); 994 shmexit_hook = NULL; 995 shmfork_hook = NULL; 996 return (0); 997} 998 999static int 1000sysctl_shmsegs(SYSCTL_HANDLER_ARGS) 1001{ 1002 1003 return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0]))); 1004} 1005 1006static int 1007sysvshm_modload(struct module *module, int cmd, void *arg) 1008{ 1009 int error = 0; 1010 1011 switch (cmd) { 1012 case MOD_LOAD: 1013 shminit(); 1014 break; 1015 case MOD_UNLOAD: 1016 error = shmunload(); 1017 break; 1018 case MOD_SHUTDOWN: 1019 break; 1020 default: 1021 error = EINVAL; 1022 break; 1023 } 1024 return (error); 1025} 1026 1027static moduledata_t sysvshm_mod = { 1028 "sysvshm", 1029 &sysvshm_modload, 1030 NULL 1031}; 1032 1033SYSCALL_MODULE_HELPER(shmsys); 1034SYSCALL_MODULE_HELPER(shmat); 1035SYSCALL_MODULE_HELPER(shmctl); 1036SYSCALL_MODULE_HELPER(shmdt); 1037SYSCALL_MODULE_HELPER(shmget); 1038 1039DECLARE_MODULE(sysvshm, sysvshm_mod, 1040 SI_SUB_SYSV_SHM, SI_ORDER_FIRST); 1041MODULE_VERSION(sysvshm, 1); 1042