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 #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 #include <sys/mac.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 #ifdef MAC_DEBUG 98 #define MPRINTF(a) printf a 99 #else 100 #define MPRINTF(a) 101 #endif 102 103 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments"); 104 105 #if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43)) 106 struct oshmctl_args; 107 static int oshmctl(struct thread *td, struct oshmctl_args *uap); 108 #endif 109 110 static int shmget_allocate_segment(struct thread *td, 111 struct shmget_args *uap, int mode); 112 static int shmget_existing(struct thread *td, struct shmget_args *uap, 113 int mode, int segnum); 114 115 #if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43)) 116 /* XXX casting to (sy_call_t *) is bogus, as usual. */ 117 static sy_call_t *shmcalls[] = { 118 (sy_call_t *)shmat, (sy_call_t *)oshmctl, 119 (sy_call_t *)shmdt, (sy_call_t *)shmget, 120 (sy_call_t *)shmctl 121 }; 122 #endif 123 124 #define SHMSEG_FREE 0x0200 125 #define SHMSEG_REMOVED 0x0400 126 #define SHMSEG_ALLOCATED 0x0800 127 #define SHMSEG_WANTED 0x1000 128 129 static int shm_last_free, shm_nused, shm_committed, shmalloced; 130 static struct shmid_kernel *shmsegs; 131 132 struct shmmap_state { 133 vm_offset_t va; 134 int shmid; 135 }; 136 137 static void shm_deallocate_segment(struct shmid_kernel *); 138 static int shm_find_segment_by_key(key_t); 139 static struct shmid_kernel *shm_find_segment_by_shmid(int); 140 static struct shmid_kernel *shm_find_segment_by_shmidx(int); 141 static int shm_delete_mapping(struct vmspace *vm, struct shmmap_state *); 142 static void shmrealloc(void); 143 static void shminit(void); 144 static int sysvshm_modload(struct module *, int, void *); 145 static int shmunload(void); 146 static void shmexit_myhook(struct vmspace *vm); 147 static void shmfork_myhook(struct proc *p1, struct proc *p2); 148 static int sysctl_shmsegs(SYSCTL_HANDLER_ARGS); 149 150 /* 151 * Tuneable values. 152 */ 153 #ifndef SHMMAXPGS 154 #define SHMMAXPGS 8192 /* Note: sysv shared memory is swap backed. */ 155 #endif 156 #ifndef SHMMAX 157 #define SHMMAX (SHMMAXPGS*PAGE_SIZE) 158 #endif 159 #ifndef SHMMIN 160 #define SHMMIN 1 161 #endif 162 #ifndef SHMMNI 163 #define SHMMNI 192 164 #endif 165 #ifndef SHMSEG 166 #define SHMSEG 128 167 #endif 168 #ifndef SHMALL 169 #define SHMALL (SHMMAXPGS) 170 #endif 171 172 struct shminfo shminfo = { 173 SHMMAX, 174 SHMMIN, 175 SHMMNI, 176 SHMSEG, 177 SHMALL 178 }; 179 180 static int shm_use_phys; 181 static int shm_allow_removed; 182 183 SYSCTL_DECL(_kern_ipc); 184 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, 185 "Maximum shared memory segment size"); 186 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, 187 "Minimum shared memory segment size"); 188 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RDTUN, &shminfo.shmmni, 0, 189 "Number of shared memory identifiers"); 190 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RDTUN, &shminfo.shmseg, 0, 191 "Number of segments per process"); 192 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, 193 "Maximum number of pages available for shared memory"); 194 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, 195 &shm_use_phys, 0, "Enable/Disable locking of shared memory pages in core"); 196 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RW, 197 &shm_allow_removed, 0, 198 "Enable/Disable attachment to attached segments marked for removal"); 199 SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLFLAG_RD, 200 NULL, 0, sysctl_shmsegs, "", 201 "Current number of shared memory segments allocated"); 202 203 static int 204 shm_find_segment_by_key(key) 205 key_t key; 206 { 207 int i; 208 209 for (i = 0; i < shmalloced; i++) 210 if ((shmsegs[i].u.shm_perm.mode & SHMSEG_ALLOCATED) && 211 shmsegs[i].u.shm_perm.key == key) 212 return (i); 213 return (-1); 214 } 215 216 static struct shmid_kernel * 217 shm_find_segment_by_shmid(int shmid) 218 { 219 int segnum; 220 struct shmid_kernel *shmseg; 221 222 segnum = IPCID_TO_IX(shmid); 223 if (segnum < 0 || segnum >= shmalloced) 224 return (NULL); 225 shmseg = &shmsegs[segnum]; 226 if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 || 227 (!shm_allow_removed && 228 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0) || 229 shmseg->u.shm_perm.seq != IPCID_TO_SEQ(shmid)) 230 return (NULL); 231 return (shmseg); 232 } 233 234 static struct shmid_kernel * 235 shm_find_segment_by_shmidx(int segnum) 236 { 237 struct shmid_kernel *shmseg; 238 239 if (segnum < 0 || segnum >= shmalloced) 240 return (NULL); 241 shmseg = &shmsegs[segnum]; 242 if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 || 243 (!shm_allow_removed && 244 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0)) 245 return (NULL); 246 return (shmseg); 247 } 248 249 static void 250 shm_deallocate_segment(shmseg) 251 struct shmid_kernel *shmseg; 252 { 253 size_t size; 254 255 GIANT_REQUIRED; 256 257 vm_object_deallocate(shmseg->u.shm_internal); 258 shmseg->u.shm_internal = NULL; 259 size = round_page(shmseg->u.shm_segsz); 260 shm_committed -= btoc(size); 261 shm_nused--; 262 shmseg->u.shm_perm.mode = SHMSEG_FREE; 263 #ifdef MAC 264 mac_cleanup_sysv_shm(shmseg); 265 #endif 266 } 267 268 static int 269 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s) 270 { 271 struct shmid_kernel *shmseg; 272 int segnum, result; 273 size_t size; 274 275 GIANT_REQUIRED; 276 277 segnum = IPCID_TO_IX(shmmap_s->shmid); 278 shmseg = &shmsegs[segnum]; 279 size = round_page(shmseg->u.shm_segsz); 280 result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size); 281 if (result != KERN_SUCCESS) 282 return (EINVAL); 283 shmmap_s->shmid = -1; 284 shmseg->u.shm_dtime = time_second; 285 if ((--shmseg->u.shm_nattch <= 0) && 286 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED)) { 287 shm_deallocate_segment(shmseg); 288 shm_last_free = segnum; 289 } 290 return (0); 291 } 292 293 #ifndef _SYS_SYSPROTO_H_ 294 struct shmdt_args { 295 const void *shmaddr; 296 }; 297 #endif 298 299 /* 300 * MPSAFE 301 */ 302 int 303 shmdt(td, uap) 304 struct thread *td; 305 struct shmdt_args *uap; 306 { 307 struct proc *p = td->td_proc; 308 struct shmmap_state *shmmap_s; 309 #ifdef MAC 310 struct shmid_kernel *shmsegptr; 311 #endif 312 int i; 313 int error = 0; 314 315 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 316 return (ENOSYS); 317 mtx_lock(&Giant); 318 shmmap_s = p->p_vmspace->vm_shm; 319 if (shmmap_s == NULL) { 320 error = EINVAL; 321 goto done2; 322 } 323 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) { 324 if (shmmap_s->shmid != -1 && 325 shmmap_s->va == (vm_offset_t)uap->shmaddr) { 326 break; 327 } 328 } 329 if (i == shminfo.shmseg) { 330 error = EINVAL; 331 goto done2; 332 } 333 #ifdef MAC 334 shmsegptr = &shmsegs[IPCID_TO_IX(shmmap_s->shmid)]; 335 error = mac_check_sysv_shmdt(td->td_ucred, shmsegptr); 336 if (error != 0) { 337 MPRINTF(("mac_check_sysv_shmdt returned %d\n", error)); 338 goto done2; 339 } 340 #endif 341 error = shm_delete_mapping(p->p_vmspace, shmmap_s); 342 done2: 343 mtx_unlock(&Giant); 344 return (error); 345 } 346 347 #ifndef _SYS_SYSPROTO_H_ 348 struct shmat_args { 349 int shmid; 350 const void *shmaddr; 351 int shmflg; 352 }; 353 #endif 354 355 /* 356 * MPSAFE 357 */ 358 int 359 kern_shmat(td, shmid, shmaddr, shmflg) 360 struct thread *td; 361 int shmid; 362 const void *shmaddr; 363 int shmflg; 364 { 365 struct proc *p = td->td_proc; 366 int i, flags; 367 struct shmid_kernel *shmseg; 368 struct shmmap_state *shmmap_s = NULL; 369 vm_offset_t attach_va; 370 vm_prot_t prot; 371 vm_size_t size; 372 int rv; 373 int error = 0; 374 375 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 376 return (ENOSYS); 377 mtx_lock(&Giant); 378 shmmap_s = p->p_vmspace->vm_shm; 379 if (shmmap_s == NULL) { 380 size = shminfo.shmseg * sizeof(struct shmmap_state); 381 shmmap_s = malloc(size, M_SHM, M_WAITOK); 382 for (i = 0; i < shminfo.shmseg; i++) 383 shmmap_s[i].shmid = -1; 384 p->p_vmspace->vm_shm = shmmap_s; 385 } 386 shmseg = shm_find_segment_by_shmid(shmid); 387 if (shmseg == NULL) { 388 error = EINVAL; 389 goto done2; 390 } 391 error = ipcperm(td, &shmseg->u.shm_perm, 392 (shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 393 if (error) 394 goto done2; 395 #ifdef MAC 396 error = mac_check_sysv_shmat(td->td_ucred, shmseg, shmflg); 397 if (error != 0) { 398 MPRINTF(("mac_check_sysv_shmat returned %d\n", error)); 399 goto done2; 400 } 401 #endif 402 for (i = 0; i < shminfo.shmseg; i++) { 403 if (shmmap_s->shmid == -1) 404 break; 405 shmmap_s++; 406 } 407 if (i >= shminfo.shmseg) { 408 error = EMFILE; 409 goto done2; 410 } 411 size = round_page(shmseg->u.shm_segsz); 412 #ifdef VM_PROT_READ_IS_EXEC 413 prot = VM_PROT_READ | VM_PROT_EXECUTE; 414 #else 415 prot = VM_PROT_READ; 416 #endif 417 if ((shmflg & SHM_RDONLY) == 0) 418 prot |= VM_PROT_WRITE; 419 flags = MAP_ANON | MAP_SHARED; 420 if (shmaddr) { 421 flags |= MAP_FIXED; 422 if (shmflg & SHM_RND) { 423 attach_va = (vm_offset_t)shmaddr & ~(SHMLBA-1); 424 } else if (((vm_offset_t)shmaddr & (SHMLBA-1)) == 0) { 425 attach_va = (vm_offset_t)shmaddr; 426 } else { 427 error = EINVAL; 428 goto done2; 429 } 430 } else { 431 /* 432 * This is just a hint to vm_map_find() about where to 433 * put it. 434 */ 435 PROC_LOCK(p); 436 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_daddr + 437 lim_max(p, RLIMIT_DATA)); 438 PROC_UNLOCK(p); 439 } 440 441 vm_object_reference(shmseg->u.shm_internal); 442 rv = vm_map_find(&p->p_vmspace->vm_map, shmseg->u.shm_internal, 443 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0); 444 if (rv != KERN_SUCCESS) { 445 vm_object_deallocate(shmseg->u.shm_internal); 446 error = ENOMEM; 447 goto done2; 448 } 449 vm_map_inherit(&p->p_vmspace->vm_map, 450 attach_va, attach_va + size, VM_INHERIT_SHARE); 451 452 shmmap_s->va = attach_va; 453 shmmap_s->shmid = shmid; 454 shmseg->u.shm_lpid = p->p_pid; 455 shmseg->u.shm_atime = time_second; 456 shmseg->u.shm_nattch++; 457 td->td_retval[0] = attach_va; 458 done2: 459 mtx_unlock(&Giant); 460 return (error); 461 } 462 463 int 464 shmat(td, uap) 465 struct thread *td; 466 struct shmat_args *uap; 467 { 468 return kern_shmat(td, uap->shmid, uap->shmaddr, uap->shmflg); 469 } 470 471 #if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43)) 472 struct oshmid_ds { 473 struct ipc_perm shm_perm; /* operation perms */ 474 int shm_segsz; /* size of segment (bytes) */ 475 u_short shm_cpid; /* pid, creator */ 476 u_short shm_lpid; /* pid, last operation */ 477 short shm_nattch; /* no. of current attaches */ 478 time_t shm_atime; /* last attach time */ 479 time_t shm_dtime; /* last detach time */ 480 time_t shm_ctime; /* last change time */ 481 void *shm_handle; /* internal handle for shm segment */ 482 }; 483 484 struct oshmctl_args { 485 int shmid; 486 int cmd; 487 struct oshmid_ds *ubuf; 488 }; 489 490 /* 491 * MPSAFE 492 */ 493 static int 494 oshmctl(td, uap) 495 struct thread *td; 496 struct oshmctl_args *uap; 497 { 498 #ifdef COMPAT_43 499 int error = 0; 500 struct shmid_kernel *shmseg; 501 struct oshmid_ds outbuf; 502 503 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 504 return (ENOSYS); 505 mtx_lock(&Giant); 506 shmseg = shm_find_segment_by_shmid(uap->shmid); 507 if (shmseg == NULL) { 508 error = EINVAL; 509 goto done2; 510 } 511 switch (uap->cmd) { 512 case IPC_STAT: 513 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R); 514 if (error) 515 goto done2; 516 #ifdef MAC 517 error = mac_check_sysv_shmctl(td->td_ucred, shmseg, uap->cmd); 518 if (error != 0) { 519 MPRINTF(("mac_check_sysv_shmctl returned %d\n", 520 error)); 521 goto done2; 522 } 523 #endif 524 outbuf.shm_perm = shmseg->u.shm_perm; 525 outbuf.shm_segsz = shmseg->u.shm_segsz; 526 outbuf.shm_cpid = shmseg->u.shm_cpid; 527 outbuf.shm_lpid = shmseg->u.shm_lpid; 528 outbuf.shm_nattch = shmseg->u.shm_nattch; 529 outbuf.shm_atime = shmseg->u.shm_atime; 530 outbuf.shm_dtime = shmseg->u.shm_dtime; 531 outbuf.shm_ctime = shmseg->u.shm_ctime; 532 outbuf.shm_handle = shmseg->u.shm_internal; 533 error = copyout(&outbuf, uap->ubuf, sizeof(outbuf)); 534 if (error) 535 goto done2; 536 break; 537 default: 538 error = shmctl(td, (struct shmctl_args *)uap); 539 break; 540 } 541 done2: 542 mtx_unlock(&Giant); 543 return (error); 544 #else 545 return (EINVAL); 546 #endif 547 } 548 #endif 549 550 #ifndef _SYS_SYSPROTO_H_ 551 struct shmctl_args { 552 int shmid; 553 int cmd; 554 struct shmid_ds *buf; 555 }; 556 #endif 557 558 /* 559 * MPSAFE 560 */ 561 int 562 kern_shmctl(td, shmid, cmd, buf, bufsz) 563 struct thread *td; 564 int shmid; 565 int cmd; 566 void *buf; 567 size_t *bufsz; 568 { 569 int error = 0; 570 struct shmid_kernel *shmseg; 571 572 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 573 return (ENOSYS); 574 575 mtx_lock(&Giant); 576 switch (cmd) { 577 case IPC_INFO: 578 memcpy(buf, &shminfo, sizeof(shminfo)); 579 if (bufsz) 580 *bufsz = sizeof(shminfo); 581 td->td_retval[0] = shmalloced; 582 goto done2; 583 case SHM_INFO: { 584 struct shm_info shm_info; 585 shm_info.used_ids = shm_nused; 586 shm_info.shm_rss = 0; /*XXX where to get from ? */ 587 shm_info.shm_tot = 0; /*XXX where to get from ? */ 588 shm_info.shm_swp = 0; /*XXX where to get from ? */ 589 shm_info.swap_attempts = 0; /*XXX where to get from ? */ 590 shm_info.swap_successes = 0; /*XXX where to get from ? */ 591 memcpy(buf, &shm_info, sizeof(shm_info)); 592 if (bufsz) 593 *bufsz = sizeof(shm_info); 594 td->td_retval[0] = shmalloced; 595 goto done2; 596 } 597 } 598 if (cmd == SHM_STAT) 599 shmseg = shm_find_segment_by_shmidx(shmid); 600 else 601 shmseg = shm_find_segment_by_shmid(shmid); 602 if (shmseg == NULL) { 603 error = EINVAL; 604 goto done2; 605 } 606 #ifdef MAC 607 error = mac_check_sysv_shmctl(td->td_ucred, shmseg, cmd); 608 if (error != 0) { 609 MPRINTF(("mac_check_sysv_shmctl returned %d\n", error)); 610 goto done2; 611 } 612 #endif 613 switch (cmd) { 614 case SHM_STAT: 615 case IPC_STAT: 616 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R); 617 if (error) 618 goto done2; 619 memcpy(buf, &shmseg->u, sizeof(struct shmid_ds)); 620 if (bufsz) 621 *bufsz = sizeof(struct shmid_ds); 622 if (cmd == SHM_STAT) 623 td->td_retval[0] = IXSEQ_TO_IPCID(shmid, shmseg->u.shm_perm); 624 break; 625 case IPC_SET: { 626 struct shmid_ds *shmid; 627 628 shmid = (struct shmid_ds *)buf; 629 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M); 630 if (error) 631 goto done2; 632 shmseg->u.shm_perm.uid = shmid->shm_perm.uid; 633 shmseg->u.shm_perm.gid = shmid->shm_perm.gid; 634 shmseg->u.shm_perm.mode = 635 (shmseg->u.shm_perm.mode & ~ACCESSPERMS) | 636 (shmid->shm_perm.mode & ACCESSPERMS); 637 shmseg->u.shm_ctime = time_second; 638 break; 639 } 640 case IPC_RMID: 641 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M); 642 if (error) 643 goto done2; 644 shmseg->u.shm_perm.key = IPC_PRIVATE; 645 shmseg->u.shm_perm.mode |= SHMSEG_REMOVED; 646 if (shmseg->u.shm_nattch <= 0) { 647 shm_deallocate_segment(shmseg); 648 shm_last_free = IPCID_TO_IX(shmid); 649 } 650 break; 651 #if 0 652 case SHM_LOCK: 653 case SHM_UNLOCK: 654 #endif 655 default: 656 error = EINVAL; 657 break; 658 } 659 done2: 660 mtx_unlock(&Giant); 661 return (error); 662 } 663 664 int 665 shmctl(td, uap) 666 struct thread *td; 667 struct shmctl_args *uap; 668 { 669 int error = 0; 670 struct shmid_ds buf; 671 size_t bufsz; 672 673 /* IPC_SET needs to copyin the buffer before calling kern_shmctl */ 674 if (uap->cmd == IPC_SET) { 675 if ((error = copyin(uap->buf, &buf, sizeof(struct shmid_ds)))) 676 goto done; 677 } 678 679 error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz); 680 if (error) 681 goto done; 682 683 /* Cases in which we need to copyout */ 684 switch (uap->cmd) { 685 case IPC_INFO: 686 case SHM_INFO: 687 case SHM_STAT: 688 case IPC_STAT: 689 error = copyout(&buf, uap->buf, bufsz); 690 break; 691 } 692 693 done: 694 if (error) { 695 /* Invalidate the return value */ 696 td->td_retval[0] = -1; 697 } 698 return (error); 699 } 700 701 702 #ifndef _SYS_SYSPROTO_H_ 703 struct shmget_args { 704 key_t key; 705 size_t size; 706 int shmflg; 707 }; 708 #endif 709 710 static int 711 shmget_existing(td, uap, mode, segnum) 712 struct thread *td; 713 struct shmget_args *uap; 714 int mode; 715 int segnum; 716 { 717 struct shmid_kernel *shmseg; 718 int error; 719 720 shmseg = &shmsegs[segnum]; 721 if (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) { 722 /* 723 * This segment is in the process of being allocated. Wait 724 * until it's done, and look the key up again (in case the 725 * allocation failed or it was freed). 726 */ 727 shmseg->u.shm_perm.mode |= SHMSEG_WANTED; 728 error = tsleep(shmseg, PLOCK | PCATCH, "shmget", 0); 729 if (error) 730 return (error); 731 return (EAGAIN); 732 } 733 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) 734 return (EEXIST); 735 #ifdef MAC 736 error = mac_check_sysv_shmget(td->td_ucred, shmseg, uap->shmflg); 737 if (error != 0) { 738 MPRINTF(("mac_check_sysv_shmget returned %d\n", error)); 739 return (error); 740 } 741 #endif 742 error = ipcperm(td, &shmseg->u.shm_perm, mode); 743 if (error) 744 return (error); 745 if (uap->size && uap->size > shmseg->u.shm_segsz) 746 return (EINVAL); 747 td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm); 748 return (0); 749 } 750 751 static int 752 shmget_allocate_segment(td, uap, mode) 753 struct thread *td; 754 struct shmget_args *uap; 755 int mode; 756 { 757 int i, segnum, shmid, size; 758 struct ucred *cred = td->td_ucred; 759 struct shmid_kernel *shmseg; 760 vm_object_t shm_object; 761 762 GIANT_REQUIRED; 763 764 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 765 return (EINVAL); 766 if (shm_nused >= shminfo.shmmni) /* Any shmids left? */ 767 return (ENOSPC); 768 size = round_page(uap->size); 769 if (shm_committed + btoc(size) > shminfo.shmall) 770 return (ENOMEM); 771 if (shm_last_free < 0) { 772 shmrealloc(); /* Maybe expand the shmsegs[] array. */ 773 for (i = 0; i < shmalloced; i++) 774 if (shmsegs[i].u.shm_perm.mode & SHMSEG_FREE) 775 break; 776 if (i == shmalloced) 777 return (ENOSPC); 778 segnum = i; 779 } else { 780 segnum = shm_last_free; 781 shm_last_free = -1; 782 } 783 shmseg = &shmsegs[segnum]; 784 /* 785 * In case we sleep in malloc(), mark the segment present but deleted 786 * so that noone else tries to create the same key. 787 */ 788 shmseg->u.shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 789 shmseg->u.shm_perm.key = uap->key; 790 shmseg->u.shm_perm.seq = (shmseg->u.shm_perm.seq + 1) & 0x7fff; 791 shmid = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm); 792 793 /* 794 * We make sure that we have allocated a pager before we need 795 * to. 796 */ 797 if (shm_use_phys) { 798 shm_object = 799 vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0); 800 } else { 801 shm_object = 802 vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0); 803 } 804 VM_OBJECT_LOCK(shm_object); 805 vm_object_clear_flag(shm_object, OBJ_ONEMAPPING); 806 vm_object_set_flag(shm_object, OBJ_NOSPLIT); 807 VM_OBJECT_UNLOCK(shm_object); 808 809 shmseg->u.shm_internal = shm_object; 810 shmseg->u.shm_perm.cuid = shmseg->u.shm_perm.uid = cred->cr_uid; 811 shmseg->u.shm_perm.cgid = shmseg->u.shm_perm.gid = cred->cr_gid; 812 shmseg->u.shm_perm.mode = (shmseg->u.shm_perm.mode & SHMSEG_WANTED) | 813 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 814 shmseg->u.shm_segsz = uap->size; 815 shmseg->u.shm_cpid = td->td_proc->p_pid; 816 shmseg->u.shm_lpid = shmseg->u.shm_nattch = 0; 817 shmseg->u.shm_atime = shmseg->u.shm_dtime = 0; 818 #ifdef MAC 819 mac_create_sysv_shm(cred, shmseg); 820 #endif 821 shmseg->u.shm_ctime = time_second; 822 shm_committed += btoc(size); 823 shm_nused++; 824 if (shmseg->u.shm_perm.mode & SHMSEG_WANTED) { 825 /* 826 * Somebody else wanted this key while we were asleep. Wake 827 * them up now. 828 */ 829 shmseg->u.shm_perm.mode &= ~SHMSEG_WANTED; 830 wakeup(shmseg); 831 } 832 td->td_retval[0] = shmid; 833 return (0); 834 } 835 836 /* 837 * MPSAFE 838 */ 839 int 840 shmget(td, uap) 841 struct thread *td; 842 struct shmget_args *uap; 843 { 844 int segnum, mode; 845 int error; 846 847 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 848 return (ENOSYS); 849 mtx_lock(&Giant); 850 mode = uap->shmflg & ACCESSPERMS; 851 if (uap->key != IPC_PRIVATE) { 852 again: 853 segnum = shm_find_segment_by_key(uap->key); 854 if (segnum >= 0) { 855 error = shmget_existing(td, uap, mode, segnum); 856 if (error == EAGAIN) 857 goto again; 858 goto done2; 859 } 860 if ((uap->shmflg & IPC_CREAT) == 0) { 861 error = ENOENT; 862 goto done2; 863 } 864 } 865 error = shmget_allocate_segment(td, uap, mode); 866 done2: 867 mtx_unlock(&Giant); 868 return (error); 869 } 870 871 /* 872 * MPSAFE 873 */ 874 int 875 shmsys(td, uap) 876 struct thread *td; 877 /* XXX actually varargs. */ 878 struct shmsys_args /* { 879 int which; 880 int a2; 881 int a3; 882 int a4; 883 } */ *uap; 884 { 885 #if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43)) 886 int error; 887 888 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 889 return (ENOSYS); 890 if (uap->which < 0 || 891 uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0])) 892 return (EINVAL); 893 mtx_lock(&Giant); 894 error = (*shmcalls[uap->which])(td, &uap->a2); 895 mtx_unlock(&Giant); 896 return (error); 897 #else 898 return (nosys(td, NULL)); 899 #endif 900 } 901 902 static void 903 shmfork_myhook(p1, p2) 904 struct proc *p1, *p2; 905 { 906 struct shmmap_state *shmmap_s; 907 size_t size; 908 int i; 909 910 mtx_lock(&Giant); 911 size = shminfo.shmseg * sizeof(struct shmmap_state); 912 shmmap_s = malloc(size, M_SHM, M_WAITOK); 913 bcopy(p1->p_vmspace->vm_shm, shmmap_s, size); 914 p2->p_vmspace->vm_shm = shmmap_s; 915 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 916 if (shmmap_s->shmid != -1) 917 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].u.shm_nattch++; 918 mtx_unlock(&Giant); 919 } 920 921 static void 922 shmexit_myhook(struct vmspace *vm) 923 { 924 struct shmmap_state *base, *shm; 925 int i; 926 927 if ((base = vm->vm_shm) != NULL) { 928 vm->vm_shm = NULL; 929 mtx_lock(&Giant); 930 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) { 931 if (shm->shmid != -1) 932 shm_delete_mapping(vm, shm); 933 } 934 mtx_unlock(&Giant); 935 free(base, M_SHM); 936 } 937 } 938 939 static void 940 shmrealloc(void) 941 { 942 int i; 943 struct shmid_kernel *newsegs; 944 945 if (shmalloced >= shminfo.shmmni) 946 return; 947 948 newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); 949 if (newsegs == NULL) 950 return; 951 for (i = 0; i < shmalloced; i++) 952 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0])); 953 for (; i < shminfo.shmmni; i++) { 954 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE; 955 shmsegs[i].u.shm_perm.seq = 0; 956 #ifdef MAC 957 mac_init_sysv_shm(&shmsegs[i]); 958 #endif 959 } 960 free(shmsegs, M_SHM); 961 shmsegs = newsegs; 962 shmalloced = shminfo.shmmni; 963 } 964 965 static void 966 shminit() 967 { 968 int i; 969 970 TUNABLE_ULONG_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall); 971 for (i = PAGE_SIZE; i > 0; i--) { 972 shminfo.shmmax = shminfo.shmall * i; 973 if (shminfo.shmmax >= shminfo.shmall) 974 break; 975 } 976 TUNABLE_ULONG_FETCH("kern.ipc.shmmin", &shminfo.shmmin); 977 TUNABLE_ULONG_FETCH("kern.ipc.shmmni", &shminfo.shmmni); 978 TUNABLE_ULONG_FETCH("kern.ipc.shmseg", &shminfo.shmseg); 979 TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys); 980 981 shmalloced = shminfo.shmmni; 982 shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); 983 if (shmsegs == NULL) 984 panic("cannot allocate initial memory for sysvshm"); 985 for (i = 0; i < shmalloced; i++) { 986 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE; 987 shmsegs[i].u.shm_perm.seq = 0; 988 #ifdef MAC 989 mac_init_sysv_shm(&shmsegs[i]); 990 #endif 991 } 992 shm_last_free = 0; 993 shm_nused = 0; 994 shm_committed = 0; 995 shmexit_hook = &shmexit_myhook; 996 shmfork_hook = &shmfork_myhook; 997 } 998 999 static int 1000 shmunload() 1001 { 1002 #ifdef MAC 1003 int i; 1004 #endif 1005 1006 if (shm_nused > 0) 1007 return (EBUSY); 1008 1009 #ifdef MAC 1010 for (i = 0; i < shmalloced; i++) 1011 mac_destroy_sysv_shm(&shmsegs[i]); 1012 #endif 1013 free(shmsegs, M_SHM); 1014 shmexit_hook = NULL; 1015 shmfork_hook = NULL; 1016 return (0); 1017 } 1018 1019 static int 1020 sysctl_shmsegs(SYSCTL_HANDLER_ARGS) 1021 { 1022 1023 return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0]))); 1024 } 1025 1026 static int 1027 sysvshm_modload(struct module *module, int cmd, void *arg) 1028 { 1029 int error = 0; 1030 1031 switch (cmd) { 1032 case MOD_LOAD: 1033 shminit(); 1034 break; 1035 case MOD_UNLOAD: 1036 error = shmunload(); 1037 break; 1038 case MOD_SHUTDOWN: 1039 break; 1040 default: 1041 error = EINVAL; 1042 break; 1043 } 1044 return (error); 1045 } 1046 1047 static moduledata_t sysvshm_mod = { 1048 "sysvshm", 1049 &sysvshm_modload, 1050 NULL 1051 }; 1052 1053 SYSCALL_MODULE_HELPER(shmsys); 1054 SYSCALL_MODULE_HELPER(shmat); 1055 SYSCALL_MODULE_HELPER(shmctl); 1056 SYSCALL_MODULE_HELPER(shmdt); 1057 SYSCALL_MODULE_HELPER(shmget); 1058 1059 DECLARE_MODULE(sysvshm, sysvshm_mod, 1060 SI_SUB_SYSV_SHM, SI_ORDER_FIRST); 1061 MODULE_VERSION(sysvshm, 1); 1062