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