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 /* 549 * It is possible that kern_shmctl is being called from the Linux ABI 550 * layer, in which case, we will need to implement IPC_INFO. It should 551 * be noted that other shmctl calls will be funneled through here for 552 * Linix binaries as well. 553 * 554 * NB: The Linux ABI layer will convert this data to structure(s) more 555 * consistent with the Linux ABI. 556 */ 557 case IPC_INFO: 558 memcpy(buf, &shminfo, sizeof(shminfo)); 559 if (bufsz) 560 *bufsz = sizeof(shminfo); 561 td->td_retval[0] = shmalloced; 562 goto done2; 563 case SHM_INFO: { 564 struct shm_info shm_info; 565 shm_info.used_ids = shm_nused; 566 shm_info.shm_rss = 0; /*XXX where to get from ? */ 567 shm_info.shm_tot = 0; /*XXX where to get from ? */ 568 shm_info.shm_swp = 0; /*XXX where to get from ? */ 569 shm_info.swap_attempts = 0; /*XXX where to get from ? */ 570 shm_info.swap_successes = 0; /*XXX where to get from ? */ 571 memcpy(buf, &shm_info, sizeof(shm_info)); 572 if (bufsz) 573 *bufsz = sizeof(shm_info); 574 td->td_retval[0] = shmalloced; 575 goto done2; 576 } 577 } 578 if (cmd == SHM_STAT) 579 shmseg = shm_find_segment_by_shmidx(shmid); 580 else 581 shmseg = shm_find_segment_by_shmid(shmid); 582 if (shmseg == NULL) { 583 error = EINVAL; 584 goto done2; 585 } 586 #ifdef MAC 587 error = mac_sysvshm_check_shmctl(td->td_ucred, shmseg, cmd); 588 if (error != 0) 589 goto done2; 590 #endif 591 switch (cmd) { 592 case SHM_STAT: 593 case IPC_STAT: 594 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R); 595 if (error) 596 goto done2; 597 memcpy(buf, &shmseg->u, sizeof(struct shmid_ds)); 598 if (bufsz) 599 *bufsz = sizeof(struct shmid_ds); 600 if (cmd == SHM_STAT) 601 td->td_retval[0] = IXSEQ_TO_IPCID(shmid, shmseg->u.shm_perm); 602 break; 603 case IPC_SET: { 604 struct shmid_ds *shmid; 605 606 shmid = (struct shmid_ds *)buf; 607 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M); 608 if (error) 609 goto done2; 610 shmseg->u.shm_perm.uid = shmid->shm_perm.uid; 611 shmseg->u.shm_perm.gid = shmid->shm_perm.gid; 612 shmseg->u.shm_perm.mode = 613 (shmseg->u.shm_perm.mode & ~ACCESSPERMS) | 614 (shmid->shm_perm.mode & ACCESSPERMS); 615 shmseg->u.shm_ctime = time_second; 616 break; 617 } 618 case IPC_RMID: 619 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M); 620 if (error) 621 goto done2; 622 shmseg->u.shm_perm.key = IPC_PRIVATE; 623 shmseg->u.shm_perm.mode |= SHMSEG_REMOVED; 624 if (shmseg->u.shm_nattch <= 0) { 625 shm_deallocate_segment(shmseg); 626 shm_last_free = IPCID_TO_IX(shmid); 627 } 628 break; 629 #if 0 630 case SHM_LOCK: 631 case SHM_UNLOCK: 632 #endif 633 default: 634 error = EINVAL; 635 break; 636 } 637 done2: 638 mtx_unlock(&Giant); 639 return (error); 640 } 641 642 int 643 shmctl(td, uap) 644 struct thread *td; 645 struct shmctl_args *uap; 646 { 647 int error = 0; 648 struct shmid_ds buf; 649 size_t bufsz; 650 651 /* 652 * The only reason IPC_INFO, SHM_INFO, SHM_STAT exists is to support 653 * Linux binaries. If we see the call come through the FreeBSD ABI, 654 * return an error back to the user since we do not to support this. 655 */ 656 if (uap->cmd == IPC_INFO || uap->cmd == SHM_INFO || 657 uap->cmd == SHM_STAT) 658 return (EINVAL); 659 660 /* IPC_SET needs to copyin the buffer before calling kern_shmctl */ 661 if (uap->cmd == IPC_SET) { 662 if ((error = copyin(uap->buf, &buf, sizeof(struct shmid_ds)))) 663 goto done; 664 } 665 666 error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz); 667 if (error) 668 goto done; 669 670 /* Cases in which we need to copyout */ 671 switch (uap->cmd) { 672 case IPC_STAT: 673 error = copyout(&buf, uap->buf, bufsz); 674 break; 675 } 676 677 done: 678 if (error) { 679 /* Invalidate the return value */ 680 td->td_retval[0] = -1; 681 } 682 return (error); 683 } 684 685 686 #ifndef _SYS_SYSPROTO_H_ 687 struct shmget_args { 688 key_t key; 689 size_t size; 690 int shmflg; 691 }; 692 #endif 693 static int 694 shmget_existing(td, uap, mode, segnum) 695 struct thread *td; 696 struct shmget_args *uap; 697 int mode; 698 int segnum; 699 { 700 struct shmid_kernel *shmseg; 701 int error; 702 703 shmseg = &shmsegs[segnum]; 704 if (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) { 705 /* 706 * This segment is in the process of being allocated. Wait 707 * until it's done, and look the key up again (in case the 708 * allocation failed or it was freed). 709 */ 710 shmseg->u.shm_perm.mode |= SHMSEG_WANTED; 711 error = tsleep(shmseg, PLOCK | PCATCH, "shmget", 0); 712 if (error) 713 return (error); 714 return (EAGAIN); 715 } 716 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) 717 return (EEXIST); 718 #ifdef MAC 719 error = mac_sysvshm_check_shmget(td->td_ucred, shmseg, uap->shmflg); 720 if (error != 0) 721 return (error); 722 #endif 723 if (uap->size && uap->size > shmseg->u.shm_segsz) 724 return (EINVAL); 725 td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm); 726 return (0); 727 } 728 729 static int 730 shmget_allocate_segment(td, uap, mode) 731 struct thread *td; 732 struct shmget_args *uap; 733 int mode; 734 { 735 int i, segnum, shmid, size; 736 struct ucred *cred = td->td_ucred; 737 struct shmid_kernel *shmseg; 738 vm_object_t shm_object; 739 740 GIANT_REQUIRED; 741 742 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 743 return (EINVAL); 744 if (shm_nused >= shminfo.shmmni) /* Any shmids left? */ 745 return (ENOSPC); 746 size = round_page(uap->size); 747 if (shm_committed + btoc(size) > shminfo.shmall) 748 return (ENOMEM); 749 if (shm_last_free < 0) { 750 shmrealloc(); /* Maybe expand the shmsegs[] array. */ 751 for (i = 0; i < shmalloced; i++) 752 if (shmsegs[i].u.shm_perm.mode & SHMSEG_FREE) 753 break; 754 if (i == shmalloced) 755 return (ENOSPC); 756 segnum = i; 757 } else { 758 segnum = shm_last_free; 759 shm_last_free = -1; 760 } 761 shmseg = &shmsegs[segnum]; 762 /* 763 * In case we sleep in malloc(), mark the segment present but deleted 764 * so that noone else tries to create the same key. 765 */ 766 shmseg->u.shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 767 shmseg->u.shm_perm.key = uap->key; 768 shmseg->u.shm_perm.seq = (shmseg->u.shm_perm.seq + 1) & 0x7fff; 769 shmid = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm); 770 771 /* 772 * We make sure that we have allocated a pager before we need 773 * to. 774 */ 775 if (shm_use_phys) { 776 shm_object = 777 vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0); 778 } else { 779 shm_object = 780 vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0); 781 } 782 VM_OBJECT_LOCK(shm_object); 783 vm_object_clear_flag(shm_object, OBJ_ONEMAPPING); 784 vm_object_set_flag(shm_object, OBJ_NOSPLIT); 785 VM_OBJECT_UNLOCK(shm_object); 786 787 shmseg->u.shm_internal = shm_object; 788 shmseg->u.shm_perm.cuid = shmseg->u.shm_perm.uid = cred->cr_uid; 789 shmseg->u.shm_perm.cgid = shmseg->u.shm_perm.gid = cred->cr_gid; 790 shmseg->u.shm_perm.mode = (shmseg->u.shm_perm.mode & SHMSEG_WANTED) | 791 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 792 shmseg->u.shm_segsz = uap->size; 793 shmseg->u.shm_cpid = td->td_proc->p_pid; 794 shmseg->u.shm_lpid = shmseg->u.shm_nattch = 0; 795 shmseg->u.shm_atime = shmseg->u.shm_dtime = 0; 796 #ifdef MAC 797 mac_sysvshm_create(cred, shmseg); 798 #endif 799 shmseg->u.shm_ctime = time_second; 800 shm_committed += btoc(size); 801 shm_nused++; 802 if (shmseg->u.shm_perm.mode & SHMSEG_WANTED) { 803 /* 804 * Somebody else wanted this key while we were asleep. Wake 805 * them up now. 806 */ 807 shmseg->u.shm_perm.mode &= ~SHMSEG_WANTED; 808 wakeup(shmseg); 809 } 810 td->td_retval[0] = shmid; 811 return (0); 812 } 813 814 int 815 shmget(td, uap) 816 struct thread *td; 817 struct shmget_args *uap; 818 { 819 int segnum, mode; 820 int error; 821 822 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 823 return (ENOSYS); 824 mtx_lock(&Giant); 825 mode = uap->shmflg & ACCESSPERMS; 826 if (uap->key != IPC_PRIVATE) { 827 again: 828 segnum = shm_find_segment_by_key(uap->key); 829 if (segnum >= 0) { 830 error = shmget_existing(td, uap, mode, segnum); 831 if (error == EAGAIN) 832 goto again; 833 goto done2; 834 } 835 if ((uap->shmflg & IPC_CREAT) == 0) { 836 error = ENOENT; 837 goto done2; 838 } 839 } 840 error = shmget_allocate_segment(td, uap, mode); 841 done2: 842 mtx_unlock(&Giant); 843 return (error); 844 } 845 846 int 847 shmsys(td, uap) 848 struct thread *td; 849 /* XXX actually varargs. */ 850 struct shmsys_args /* { 851 int which; 852 int a2; 853 int a3; 854 int a4; 855 } */ *uap; 856 { 857 #if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43)) 858 int error; 859 860 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 861 return (ENOSYS); 862 if (uap->which < 0 || 863 uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0])) 864 return (EINVAL); 865 mtx_lock(&Giant); 866 error = (*shmcalls[uap->which])(td, &uap->a2); 867 mtx_unlock(&Giant); 868 return (error); 869 #else 870 return (nosys(td, NULL)); 871 #endif 872 } 873 874 static void 875 shmfork_myhook(p1, p2) 876 struct proc *p1, *p2; 877 { 878 struct shmmap_state *shmmap_s; 879 size_t size; 880 int i; 881 882 mtx_lock(&Giant); 883 size = shminfo.shmseg * sizeof(struct shmmap_state); 884 shmmap_s = malloc(size, M_SHM, M_WAITOK); 885 bcopy(p1->p_vmspace->vm_shm, shmmap_s, size); 886 p2->p_vmspace->vm_shm = shmmap_s; 887 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 888 if (shmmap_s->shmid != -1) 889 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].u.shm_nattch++; 890 mtx_unlock(&Giant); 891 } 892 893 static void 894 shmexit_myhook(struct vmspace *vm) 895 { 896 struct shmmap_state *base, *shm; 897 int i; 898 899 if ((base = vm->vm_shm) != NULL) { 900 vm->vm_shm = NULL; 901 mtx_lock(&Giant); 902 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) { 903 if (shm->shmid != -1) 904 shm_delete_mapping(vm, shm); 905 } 906 mtx_unlock(&Giant); 907 free(base, M_SHM); 908 } 909 } 910 911 static void 912 shmrealloc(void) 913 { 914 int i; 915 struct shmid_kernel *newsegs; 916 917 if (shmalloced >= shminfo.shmmni) 918 return; 919 920 newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); 921 if (newsegs == NULL) 922 return; 923 for (i = 0; i < shmalloced; i++) 924 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0])); 925 for (; i < shminfo.shmmni; i++) { 926 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE; 927 shmsegs[i].u.shm_perm.seq = 0; 928 #ifdef MAC 929 mac_sysvshm_init(&shmsegs[i]); 930 #endif 931 } 932 free(shmsegs, M_SHM); 933 shmsegs = newsegs; 934 shmalloced = shminfo.shmmni; 935 } 936 937 static void 938 shminit() 939 { 940 int i; 941 942 TUNABLE_ULONG_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall); 943 for (i = PAGE_SIZE; i > 0; i--) { 944 shminfo.shmmax = shminfo.shmall * i; 945 if (shminfo.shmmax >= shminfo.shmall) 946 break; 947 } 948 TUNABLE_ULONG_FETCH("kern.ipc.shmmin", &shminfo.shmmin); 949 TUNABLE_ULONG_FETCH("kern.ipc.shmmni", &shminfo.shmmni); 950 TUNABLE_ULONG_FETCH("kern.ipc.shmseg", &shminfo.shmseg); 951 TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys); 952 953 shmalloced = shminfo.shmmni; 954 shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); 955 if (shmsegs == NULL) 956 panic("cannot allocate initial memory for sysvshm"); 957 for (i = 0; i < shmalloced; i++) { 958 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE; 959 shmsegs[i].u.shm_perm.seq = 0; 960 #ifdef MAC 961 mac_sysvshm_init(&shmsegs[i]); 962 #endif 963 } 964 shm_last_free = 0; 965 shm_nused = 0; 966 shm_committed = 0; 967 shmexit_hook = &shmexit_myhook; 968 shmfork_hook = &shmfork_myhook; 969 } 970 971 static int 972 shmunload() 973 { 974 #ifdef MAC 975 int i; 976 #endif 977 978 if (shm_nused > 0) 979 return (EBUSY); 980 981 #ifdef MAC 982 for (i = 0; i < shmalloced; i++) 983 mac_sysvshm_destroy(&shmsegs[i]); 984 #endif 985 free(shmsegs, M_SHM); 986 shmexit_hook = NULL; 987 shmfork_hook = NULL; 988 return (0); 989 } 990 991 static int 992 sysctl_shmsegs(SYSCTL_HANDLER_ARGS) 993 { 994 995 return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0]))); 996 } 997 998 static int 999 sysvshm_modload(struct module *module, int cmd, void *arg) 1000 { 1001 int error = 0; 1002 1003 switch (cmd) { 1004 case MOD_LOAD: 1005 shminit(); 1006 break; 1007 case MOD_UNLOAD: 1008 error = shmunload(); 1009 break; 1010 case MOD_SHUTDOWN: 1011 break; 1012 default: 1013 error = EINVAL; 1014 break; 1015 } 1016 return (error); 1017 } 1018 1019 static moduledata_t sysvshm_mod = { 1020 "sysvshm", 1021 &sysvshm_modload, 1022 NULL 1023 }; 1024 1025 SYSCALL_MODULE_HELPER(shmsys); 1026 SYSCALL_MODULE_HELPER(shmat); 1027 SYSCALL_MODULE_HELPER(shmctl); 1028 SYSCALL_MODULE_HELPER(shmdt); 1029 SYSCALL_MODULE_HELPER(shmget); 1030 1031 DECLARE_MODULE(sysvshm, sysvshm_mod, 1032 SI_SUB_SYSV_SHM, SI_ORDER_FIRST); 1033 MODULE_VERSION(sysvshm, 1); 1034