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 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 98 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments"); 99 100 #if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43)) 101 struct oshmctl_args; 102 static int oshmctl(struct thread *td, struct oshmctl_args *uap); 103 #endif 104 105 static int shmget_allocate_segment(struct thread *td, 106 struct shmget_args *uap, int mode); 107 static 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. */ 112 static 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 123 124 static int shm_last_free, shm_nused, shm_committed, shmalloced; 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 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_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 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_ 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 (!jail_sysvipc_allowed && jailed(td->td_ucred)) 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 (!jail_sysvipc_allowed && jailed(td->td_ucred)) 360 return (ENOSYS); 361 mtx_lock(&Giant); 362 shmmap_s = p->p_vmspace->vm_shm; 363 if (shmmap_s == NULL) { 364 size = shminfo.shmseg * sizeof(struct shmmap_state); 365 shmmap_s = malloc(size, 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->u.shm_segsz); 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)?0:1, prot, prot, 0); 426 if (rv != KERN_SUCCESS) { 427 vm_object_deallocate(shmseg->u.shm_internal); 428 error = ENOMEM; 429 goto done2; 430 } 431 vm_map_inherit(&p->p_vmspace->vm_map, 432 attach_va, attach_va + size, VM_INHERIT_SHARE); 433 434 shmmap_s->va = attach_va; 435 shmmap_s->shmid = shmid; 436 shmseg->u.shm_lpid = p->p_pid; 437 shmseg->u.shm_atime = time_second; 438 shmseg->u.shm_nattch++; 439 td->td_retval[0] = attach_va; 440 done2: 441 mtx_unlock(&Giant); 442 return (error); 443 } 444 445 int 446 shmat(td, uap) 447 struct thread *td; 448 struct shmat_args *uap; 449 { 450 return kern_shmat(td, uap->shmid, uap->shmaddr, uap->shmflg); 451 } 452 453 #if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43)) 454 struct oshmid_ds { 455 struct ipc_perm shm_perm; /* operation perms */ 456 int shm_segsz; /* size of segment (bytes) */ 457 u_short shm_cpid; /* pid, creator */ 458 u_short shm_lpid; /* pid, last operation */ 459 short shm_nattch; /* no. of current attaches */ 460 time_t shm_atime; /* last attach time */ 461 time_t shm_dtime; /* last detach time */ 462 time_t shm_ctime; /* last change time */ 463 void *shm_handle; /* internal handle for shm segment */ 464 }; 465 466 struct oshmctl_args { 467 int shmid; 468 int cmd; 469 struct oshmid_ds *ubuf; 470 }; 471 static int 472 oshmctl(td, uap) 473 struct thread *td; 474 struct oshmctl_args *uap; 475 { 476 #ifdef COMPAT_43 477 int error = 0; 478 struct shmid_kernel *shmseg; 479 struct oshmid_ds outbuf; 480 481 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 482 return (ENOSYS); 483 mtx_lock(&Giant); 484 shmseg = shm_find_segment_by_shmid(uap->shmid); 485 if (shmseg == NULL) { 486 error = EINVAL; 487 goto done2; 488 } 489 switch (uap->cmd) { 490 case IPC_STAT: 491 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R); 492 if (error) 493 goto done2; 494 #ifdef MAC 495 error = mac_sysvshm_check_shmctl(td->td_ucred, shmseg, uap->cmd); 496 if (error != 0) 497 goto done2; 498 #endif 499 outbuf.shm_perm = shmseg->u.shm_perm; 500 outbuf.shm_segsz = shmseg->u.shm_segsz; 501 outbuf.shm_cpid = shmseg->u.shm_cpid; 502 outbuf.shm_lpid = shmseg->u.shm_lpid; 503 outbuf.shm_nattch = shmseg->u.shm_nattch; 504 outbuf.shm_atime = shmseg->u.shm_atime; 505 outbuf.shm_dtime = shmseg->u.shm_dtime; 506 outbuf.shm_ctime = shmseg->u.shm_ctime; 507 outbuf.shm_handle = shmseg->u.shm_internal; 508 error = copyout(&outbuf, uap->ubuf, sizeof(outbuf)); 509 if (error) 510 goto done2; 511 break; 512 default: 513 error = shmctl(td, (struct shmctl_args *)uap); 514 break; 515 } 516 done2: 517 mtx_unlock(&Giant); 518 return (error); 519 #else 520 return (EINVAL); 521 #endif 522 } 523 #endif 524 525 #ifndef _SYS_SYSPROTO_H_ 526 struct shmctl_args { 527 int shmid; 528 int cmd; 529 struct shmid_ds *buf; 530 }; 531 #endif 532 int 533 kern_shmctl(td, shmid, cmd, buf, bufsz) 534 struct thread *td; 535 int shmid; 536 int cmd; 537 void *buf; 538 size_t *bufsz; 539 { 540 int error = 0; 541 struct shmid_kernel *shmseg; 542 543 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 544 return (ENOSYS); 545 546 mtx_lock(&Giant); 547 switch (cmd) { 548 case IPC_INFO: 549 memcpy(buf, &shminfo, sizeof(shminfo)); 550 if (bufsz) 551 *bufsz = sizeof(shminfo); 552 td->td_retval[0] = shmalloced; 553 goto done2; 554 case SHM_INFO: { 555 struct shm_info shm_info; 556 shm_info.used_ids = shm_nused; 557 shm_info.shm_rss = 0; /*XXX where to get from ? */ 558 shm_info.shm_tot = 0; /*XXX where to get from ? */ 559 shm_info.shm_swp = 0; /*XXX where to get from ? */ 560 shm_info.swap_attempts = 0; /*XXX where to get from ? */ 561 shm_info.swap_successes = 0; /*XXX where to get from ? */ 562 memcpy(buf, &shm_info, sizeof(shm_info)); 563 if (bufsz) 564 *bufsz = sizeof(shm_info); 565 td->td_retval[0] = shmalloced; 566 goto done2; 567 } 568 } 569 if (cmd == SHM_STAT) 570 shmseg = shm_find_segment_by_shmidx(shmid); 571 else 572 shmseg = shm_find_segment_by_shmid(shmid); 573 if (shmseg == NULL) { 574 error = EINVAL; 575 goto done2; 576 } 577 #ifdef MAC 578 error = mac_sysvshm_check_shmctl(td->td_ucred, shmseg, cmd); 579 if (error != 0) 580 goto done2; 581 #endif 582 switch (cmd) { 583 case SHM_STAT: 584 case IPC_STAT: 585 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R); 586 if (error) 587 goto done2; 588 memcpy(buf, &shmseg->u, sizeof(struct shmid_ds)); 589 if (bufsz) 590 *bufsz = sizeof(struct shmid_ds); 591 if (cmd == SHM_STAT) 592 td->td_retval[0] = IXSEQ_TO_IPCID(shmid, shmseg->u.shm_perm); 593 break; 594 case IPC_SET: { 595 struct shmid_ds *shmid; 596 597 shmid = (struct shmid_ds *)buf; 598 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M); 599 if (error) 600 goto done2; 601 shmseg->u.shm_perm.uid = shmid->shm_perm.uid; 602 shmseg->u.shm_perm.gid = shmid->shm_perm.gid; 603 shmseg->u.shm_perm.mode = 604 (shmseg->u.shm_perm.mode & ~ACCESSPERMS) | 605 (shmid->shm_perm.mode & ACCESSPERMS); 606 shmseg->u.shm_ctime = time_second; 607 break; 608 } 609 case IPC_RMID: 610 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M); 611 if (error) 612 goto done2; 613 shmseg->u.shm_perm.key = IPC_PRIVATE; 614 shmseg->u.shm_perm.mode |= SHMSEG_REMOVED; 615 if (shmseg->u.shm_nattch <= 0) { 616 shm_deallocate_segment(shmseg); 617 shm_last_free = IPCID_TO_IX(shmid); 618 } 619 break; 620 #if 0 621 case SHM_LOCK: 622 case SHM_UNLOCK: 623 #endif 624 default: 625 error = EINVAL; 626 break; 627 } 628 done2: 629 mtx_unlock(&Giant); 630 return (error); 631 } 632 633 int 634 shmctl(td, uap) 635 struct thread *td; 636 struct shmctl_args *uap; 637 { 638 int error = 0; 639 struct shmid_ds buf; 640 size_t bufsz; 641 642 /* IPC_SET needs to copyin the buffer before calling kern_shmctl */ 643 if (uap->cmd == IPC_SET) { 644 if ((error = copyin(uap->buf, &buf, sizeof(struct shmid_ds)))) 645 goto done; 646 } 647 648 error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz); 649 if (error) 650 goto done; 651 652 /* Cases in which we need to copyout */ 653 switch (uap->cmd) { 654 case IPC_INFO: 655 case SHM_INFO: 656 case SHM_STAT: 657 case IPC_STAT: 658 error = copyout(&buf, uap->buf, bufsz); 659 break; 660 } 661 662 done: 663 if (error) { 664 /* Invalidate the return value */ 665 td->td_retval[0] = -1; 666 } 667 return (error); 668 } 669 670 671 #ifndef _SYS_SYSPROTO_H_ 672 struct shmget_args { 673 key_t key; 674 size_t size; 675 int shmflg; 676 }; 677 #endif 678 static int 679 shmget_existing(td, uap, mode, segnum) 680 struct thread *td; 681 struct shmget_args *uap; 682 int mode; 683 int segnum; 684 { 685 struct shmid_kernel *shmseg; 686 int error; 687 688 shmseg = &shmsegs[segnum]; 689 if (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) { 690 /* 691 * This segment is in the process of being allocated. Wait 692 * until it's done, and look the key up again (in case the 693 * allocation failed or it was freed). 694 */ 695 shmseg->u.shm_perm.mode |= SHMSEG_WANTED; 696 error = tsleep(shmseg, PLOCK | PCATCH, "shmget", 0); 697 if (error) 698 return (error); 699 return (EAGAIN); 700 } 701 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) 702 return (EEXIST); 703 #ifdef MAC 704 error = mac_sysvshm_check_shmget(td->td_ucred, shmseg, uap->shmflg); 705 if (error != 0) 706 return (error); 707 #endif 708 if (uap->size && uap->size > shmseg->u.shm_segsz) 709 return (EINVAL); 710 td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm); 711 return (0); 712 } 713 714 static int 715 shmget_allocate_segment(td, uap, mode) 716 struct thread *td; 717 struct shmget_args *uap; 718 int mode; 719 { 720 int i, segnum, shmid, size; 721 struct ucred *cred = td->td_ucred; 722 struct shmid_kernel *shmseg; 723 vm_object_t shm_object; 724 725 GIANT_REQUIRED; 726 727 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 728 return (EINVAL); 729 if (shm_nused >= shminfo.shmmni) /* Any shmids left? */ 730 return (ENOSPC); 731 size = round_page(uap->size); 732 if (shm_committed + btoc(size) > shminfo.shmall) 733 return (ENOMEM); 734 if (shm_last_free < 0) { 735 shmrealloc(); /* Maybe expand the shmsegs[] array. */ 736 for (i = 0; i < shmalloced; i++) 737 if (shmsegs[i].u.shm_perm.mode & SHMSEG_FREE) 738 break; 739 if (i == shmalloced) 740 return (ENOSPC); 741 segnum = i; 742 } else { 743 segnum = shm_last_free; 744 shm_last_free = -1; 745 } 746 shmseg = &shmsegs[segnum]; 747 /* 748 * In case we sleep in malloc(), mark the segment present but deleted 749 * so that noone else tries to create the same key. 750 */ 751 shmseg->u.shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 752 shmseg->u.shm_perm.key = uap->key; 753 shmseg->u.shm_perm.seq = (shmseg->u.shm_perm.seq + 1) & 0x7fff; 754 shmid = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm); 755 756 /* 757 * We make sure that we have allocated a pager before we need 758 * to. 759 */ 760 if (shm_use_phys) { 761 shm_object = 762 vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0); 763 } else { 764 shm_object = 765 vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0); 766 } 767 VM_OBJECT_LOCK(shm_object); 768 vm_object_clear_flag(shm_object, OBJ_ONEMAPPING); 769 vm_object_set_flag(shm_object, OBJ_NOSPLIT); 770 VM_OBJECT_UNLOCK(shm_object); 771 772 shmseg->u.shm_internal = shm_object; 773 shmseg->u.shm_perm.cuid = shmseg->u.shm_perm.uid = cred->cr_uid; 774 shmseg->u.shm_perm.cgid = shmseg->u.shm_perm.gid = cred->cr_gid; 775 shmseg->u.shm_perm.mode = (shmseg->u.shm_perm.mode & SHMSEG_WANTED) | 776 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 777 shmseg->u.shm_segsz = uap->size; 778 shmseg->u.shm_cpid = td->td_proc->p_pid; 779 shmseg->u.shm_lpid = shmseg->u.shm_nattch = 0; 780 shmseg->u.shm_atime = shmseg->u.shm_dtime = 0; 781 #ifdef MAC 782 mac_sysvshm_create(cred, shmseg); 783 #endif 784 shmseg->u.shm_ctime = time_second; 785 shm_committed += btoc(size); 786 shm_nused++; 787 if (shmseg->u.shm_perm.mode & SHMSEG_WANTED) { 788 /* 789 * Somebody else wanted this key while we were asleep. Wake 790 * them up now. 791 */ 792 shmseg->u.shm_perm.mode &= ~SHMSEG_WANTED; 793 wakeup(shmseg); 794 } 795 td->td_retval[0] = shmid; 796 return (0); 797 } 798 799 int 800 shmget(td, uap) 801 struct thread *td; 802 struct shmget_args *uap; 803 { 804 int segnum, mode; 805 int error; 806 807 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 808 return (ENOSYS); 809 mtx_lock(&Giant); 810 mode = uap->shmflg & ACCESSPERMS; 811 if (uap->key != IPC_PRIVATE) { 812 again: 813 segnum = shm_find_segment_by_key(uap->key); 814 if (segnum >= 0) { 815 error = shmget_existing(td, uap, mode, segnum); 816 if (error == EAGAIN) 817 goto again; 818 goto done2; 819 } 820 if ((uap->shmflg & IPC_CREAT) == 0) { 821 error = ENOENT; 822 goto done2; 823 } 824 } 825 error = shmget_allocate_segment(td, uap, mode); 826 done2: 827 mtx_unlock(&Giant); 828 return (error); 829 } 830 831 int 832 shmsys(td, uap) 833 struct thread *td; 834 /* XXX actually varargs. */ 835 struct shmsys_args /* { 836 int which; 837 int a2; 838 int a3; 839 int a4; 840 } */ *uap; 841 { 842 #if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43)) 843 int error; 844 845 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 846 return (ENOSYS); 847 if (uap->which < 0 || 848 uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0])) 849 return (EINVAL); 850 mtx_lock(&Giant); 851 error = (*shmcalls[uap->which])(td, &uap->a2); 852 mtx_unlock(&Giant); 853 return (error); 854 #else 855 return (nosys(td, NULL)); 856 #endif 857 } 858 859 static void 860 shmfork_myhook(p1, p2) 861 struct proc *p1, *p2; 862 { 863 struct shmmap_state *shmmap_s; 864 size_t size; 865 int i; 866 867 mtx_lock(&Giant); 868 size = shminfo.shmseg * sizeof(struct shmmap_state); 869 shmmap_s = malloc(size, M_SHM, M_WAITOK); 870 bcopy(p1->p_vmspace->vm_shm, shmmap_s, size); 871 p2->p_vmspace->vm_shm = shmmap_s; 872 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 873 if (shmmap_s->shmid != -1) 874 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].u.shm_nattch++; 875 mtx_unlock(&Giant); 876 } 877 878 static void 879 shmexit_myhook(struct vmspace *vm) 880 { 881 struct shmmap_state *base, *shm; 882 int i; 883 884 if ((base = vm->vm_shm) != NULL) { 885 vm->vm_shm = NULL; 886 mtx_lock(&Giant); 887 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) { 888 if (shm->shmid != -1) 889 shm_delete_mapping(vm, shm); 890 } 891 mtx_unlock(&Giant); 892 free(base, M_SHM); 893 } 894 } 895 896 static void 897 shmrealloc(void) 898 { 899 int i; 900 struct shmid_kernel *newsegs; 901 902 if (shmalloced >= shminfo.shmmni) 903 return; 904 905 newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); 906 if (newsegs == NULL) 907 return; 908 for (i = 0; i < shmalloced; i++) 909 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0])); 910 for (; i < shminfo.shmmni; i++) { 911 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE; 912 shmsegs[i].u.shm_perm.seq = 0; 913 #ifdef MAC 914 mac_sysvshm_init(&shmsegs[i]); 915 #endif 916 } 917 free(shmsegs, M_SHM); 918 shmsegs = newsegs; 919 shmalloced = shminfo.shmmni; 920 } 921 922 static void 923 shminit() 924 { 925 int i; 926 927 TUNABLE_ULONG_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall); 928 for (i = PAGE_SIZE; i > 0; i--) { 929 shminfo.shmmax = shminfo.shmall * i; 930 if (shminfo.shmmax >= shminfo.shmall) 931 break; 932 } 933 TUNABLE_ULONG_FETCH("kern.ipc.shmmin", &shminfo.shmmin); 934 TUNABLE_ULONG_FETCH("kern.ipc.shmmni", &shminfo.shmmni); 935 TUNABLE_ULONG_FETCH("kern.ipc.shmseg", &shminfo.shmseg); 936 TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys); 937 938 shmalloced = shminfo.shmmni; 939 shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); 940 if (shmsegs == NULL) 941 panic("cannot allocate initial memory for sysvshm"); 942 for (i = 0; i < shmalloced; i++) { 943 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE; 944 shmsegs[i].u.shm_perm.seq = 0; 945 #ifdef MAC 946 mac_sysvshm_init(&shmsegs[i]); 947 #endif 948 } 949 shm_last_free = 0; 950 shm_nused = 0; 951 shm_committed = 0; 952 shmexit_hook = &shmexit_myhook; 953 shmfork_hook = &shmfork_myhook; 954 } 955 956 static int 957 shmunload() 958 { 959 #ifdef MAC 960 int i; 961 #endif 962 963 if (shm_nused > 0) 964 return (EBUSY); 965 966 #ifdef MAC 967 for (i = 0; i < shmalloced; i++) 968 mac_sysvshm_destroy(&shmsegs[i]); 969 #endif 970 free(shmsegs, M_SHM); 971 shmexit_hook = NULL; 972 shmfork_hook = NULL; 973 return (0); 974 } 975 976 static int 977 sysctl_shmsegs(SYSCTL_HANDLER_ARGS) 978 { 979 980 return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0]))); 981 } 982 983 static int 984 sysvshm_modload(struct module *module, int cmd, void *arg) 985 { 986 int error = 0; 987 988 switch (cmd) { 989 case MOD_LOAD: 990 shminit(); 991 break; 992 case MOD_UNLOAD: 993 error = shmunload(); 994 break; 995 case MOD_SHUTDOWN: 996 break; 997 default: 998 error = EINVAL; 999 break; 1000 } 1001 return (error); 1002 } 1003 1004 static moduledata_t sysvshm_mod = { 1005 "sysvshm", 1006 &sysvshm_modload, 1007 NULL 1008 }; 1009 1010 SYSCALL_MODULE_HELPER(shmsys); 1011 SYSCALL_MODULE_HELPER(shmat); 1012 SYSCALL_MODULE_HELPER(shmctl); 1013 SYSCALL_MODULE_HELPER(shmdt); 1014 SYSCALL_MODULE_HELPER(shmget); 1015 1016 DECLARE_MODULE(sysvshm, sysvshm_mod, 1017 SI_SUB_SYSV_SHM, SI_ORDER_FIRST); 1018 MODULE_VERSION(sysvshm, 1); 1019