sysv_shm.c revision 1.29
1 /* $NetBSD: sysv_shm.c,v 1.29 1995/06/05 12:57:07 pk Exp $ */ 2 3 /* 4 * Copyright (c) 1994 Adam Glass and Charles Hannum. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Adam Glass and Charles 17 * Hannum. 18 * 4. The names of the authors may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #include <sys/types.h> 34 #include <sys/param.h> 35 #include <sys/kernel.h> 36 #include <sys/shm.h> 37 #include <sys/proc.h> 38 #include <sys/uio.h> 39 #include <sys/time.h> 40 #include <sys/malloc.h> 41 #include <sys/mman.h> 42 #include <sys/systm.h> 43 #include <sys/stat.h> 44 45 #include <sys/mount.h> 46 #include <sys/syscallargs.h> 47 48 #include <vm/vm.h> 49 #include <vm/vm_map.h> 50 #include <vm/vm_map.h> 51 #include <vm/vm_kern.h> 52 53 /* 54 * Provides the following externally accessible functions: 55 * 56 * shminit(void); initialization 57 * shmexit(struct proc *) cleanup 58 * shmfork(struct proc *, struct proc *, int) fork handling 59 * shmsys(arg1, arg2, arg3, arg4); shm{at,ctl,dt,get}(arg2, arg3, arg4) 60 * 61 * Structures: 62 * shmsegs (an array of 'struct shmid_ds') 63 * per proc array of 'struct shmmap_state' 64 */ 65 66 #define SHMSEG_FREE 0x0200 67 #define SHMSEG_REMOVED 0x0400 68 #define SHMSEG_ALLOCATED 0x0800 69 #define SHMSEG_WANTED 0x1000 70 71 vm_map_t sysvshm_map; 72 int shm_last_free, shm_nused, shm_committed; 73 74 struct shm_handle { 75 vm_offset_t kva; 76 }; 77 78 struct shmmap_state { 79 vm_offset_t va; 80 int shmid; 81 }; 82 83 static void shm_deallocate_segment __P((struct shmid_ds *)); 84 static int shm_find_segment_by_key __P((key_t)); 85 struct shmid_ds *shm_find_segment_by_shmid __P((int)); 86 static int shm_delete_mapping __P((struct proc *, struct shmmap_state *)); 87 88 static int 89 shm_find_segment_by_key(key) 90 key_t key; 91 { 92 int i; 93 94 for (i = 0; i < shminfo.shmmni; i++) 95 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 96 shmsegs[i].shm_perm.key == key) 97 return i; 98 return -1; 99 } 100 101 struct shmid_ds * 102 shm_find_segment_by_shmid(shmid) 103 int shmid; 104 { 105 int segnum; 106 struct shmid_ds *shmseg; 107 108 segnum = IPCID_TO_IX(shmid); 109 if (segnum < 0 || segnum >= shminfo.shmmni) 110 return NULL; 111 shmseg = &shmsegs[segnum]; 112 if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED)) 113 != SHMSEG_ALLOCATED || 114 shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid)) 115 return NULL; 116 return shmseg; 117 } 118 119 static void 120 shm_deallocate_segment(shmseg) 121 struct shmid_ds *shmseg; 122 { 123 struct shm_handle *shm_handle; 124 size_t size; 125 126 shm_handle = shmseg->shm_internal; 127 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 128 vm_deallocate(sysvshm_map, shm_handle->kva, size); 129 free((caddr_t)shm_handle, M_SHM); 130 shmseg->shm_internal = NULL; 131 shm_committed -= btoc(size); 132 shmseg->shm_perm.mode = SHMSEG_FREE; 133 shm_nused--; 134 } 135 136 static int 137 shm_delete_mapping(p, shmmap_s) 138 struct proc *p; 139 struct shmmap_state *shmmap_s; 140 { 141 struct shmid_ds *shmseg; 142 int segnum, result; 143 size_t size; 144 145 segnum = IPCID_TO_IX(shmmap_s->shmid); 146 shmseg = &shmsegs[segnum]; 147 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 148 result = vm_deallocate(&p->p_vmspace->vm_map, shmmap_s->va, size); 149 if (result != KERN_SUCCESS) 150 return EINVAL; 151 shmmap_s->shmid = -1; 152 shmseg->shm_dtime = time.tv_sec; 153 if ((--shmseg->shm_nattch <= 0) && 154 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 155 shm_deallocate_segment(shmseg); 156 shm_last_free = segnum; 157 } 158 return 0; 159 } 160 161 int 162 shmdt(p, uap, retval) 163 struct proc *p; 164 struct shmdt_args /* { 165 syscallarg(void *) shmaddr; 166 } */ *uap; 167 register_t *retval; 168 { 169 struct shmmap_state *shmmap_s; 170 int i; 171 172 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 173 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 174 if (shmmap_s->shmid != -1 && 175 shmmap_s->va == (vm_offset_t)SCARG(uap, shmaddr)) 176 break; 177 if (i == shminfo.shmseg) 178 return EINVAL; 179 return shm_delete_mapping(p, shmmap_s); 180 } 181 182 int 183 shmat(p, uap, retval) 184 struct proc *p; 185 struct shmat_args /* { 186 syscallarg(int) shmid; 187 syscallarg(void *) shmaddr; 188 syscallarg(int) shmflag; 189 } */ *uap; 190 register_t *retval; 191 { 192 int error, i, flags; 193 struct ucred *cred = p->p_ucred; 194 struct shmid_ds *shmseg; 195 struct shmmap_state *shmmap_s = NULL; 196 vm_offset_t attach_va; 197 vm_prot_t prot; 198 vm_size_t size; 199 200 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 201 if (shmmap_s == NULL) { 202 size = shminfo.shmseg * sizeof(struct shmmap_state); 203 shmmap_s = malloc(size, M_SHM, M_WAITOK); 204 for (i = 0; i < shminfo.shmseg; i++) 205 shmmap_s[i].shmid = -1; 206 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 207 } 208 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 209 if (shmseg == NULL) 210 return EINVAL; 211 if (error = ipcperm(cred, &shmseg->shm_perm, 212 (SCARG(uap, shmflg) & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W)) 213 return error; 214 for (i = 0; i < shminfo.shmseg; i++) { 215 if (shmmap_s->shmid == -1) 216 break; 217 shmmap_s++; 218 } 219 if (i >= shminfo.shmseg) 220 return EMFILE; 221 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 222 prot = VM_PROT_READ; 223 if ((SCARG(uap, shmflg) & SHM_RDONLY) == 0) 224 prot |= VM_PROT_WRITE; 225 flags = MAP_ANON | MAP_SHARED; 226 if (SCARG(uap, shmaddr)) { 227 flags |= MAP_FIXED; 228 if (SCARG(uap, shmflg) & SHM_RND) 229 attach_va = 230 (vm_offset_t)SCARG(uap, shmaddr) & ~(SHMLBA-1); 231 else if (((vm_offset_t)SCARG(uap, shmaddr) & (SHMLBA-1)) == 0) 232 attach_va = (vm_offset_t)SCARG(uap, shmaddr); 233 else 234 return EINVAL; 235 } else { 236 /* This is just a hint to vm_mmap() about where to put it. */ 237 attach_va = round_page(p->p_vmspace->vm_daddr + MAXDSIZ); 238 } 239 error = vm_mmap(&p->p_vmspace->vm_map, &attach_va, size, prot, 240 VM_PROT_DEFAULT, flags, (caddr_t)(long)SCARG(uap, shmid), 0); 241 if (error) 242 return error; 243 shmmap_s->va = attach_va; 244 shmmap_s->shmid = SCARG(uap, shmid); 245 shmseg->shm_lpid = p->p_pid; 246 shmseg->shm_atime = time.tv_sec; 247 shmseg->shm_nattch++; 248 *retval = attach_va; 249 return 0; 250 } 251 252 int 253 shmctl(p, uap, retval) 254 struct proc *p; 255 struct shmctl_args /* { 256 syscallarg(int) shmid; 257 syscallarg(int) cmd; 258 syscallarg(struct shmid_ds *) buf; 259 } */ *uap; 260 register_t *retval; 261 { 262 int error, segnum; 263 struct ucred *cred = p->p_ucred; 264 struct shmid_ds inbuf; 265 struct shmid_ds *shmseg; 266 267 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 268 if (shmseg == NULL) 269 return EINVAL; 270 switch (SCARG(uap, cmd)) { 271 case IPC_STAT: 272 if (error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) 273 return error; 274 if (error = copyout((caddr_t)shmseg, SCARG(uap, buf), 275 sizeof(inbuf))) 276 return error; 277 break; 278 case IPC_SET: 279 if (error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) 280 return error; 281 if (error = copyin(SCARG(uap, buf), (caddr_t)&inbuf, 282 sizeof(inbuf))) 283 return error; 284 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 285 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 286 shmseg->shm_perm.mode = 287 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 288 (inbuf.shm_perm.mode & ACCESSPERMS); 289 shmseg->shm_ctime = time.tv_sec; 290 break; 291 case IPC_RMID: 292 if (error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) 293 return error; 294 shmseg->shm_perm.key = IPC_PRIVATE; 295 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 296 if (shmseg->shm_nattch <= 0) { 297 shm_deallocate_segment(shmseg); 298 shm_last_free = IPCID_TO_IX(SCARG(uap, shmid)); 299 } 300 break; 301 case SHM_LOCK: 302 case SHM_UNLOCK: 303 default: 304 return EINVAL; 305 } 306 return 0; 307 } 308 309 static int 310 shmget_existing(p, uap, mode, segnum, retval) 311 struct proc *p; 312 struct shmget_args /* { 313 syscallarg(key_t) key; 314 syscallarg(int) size; 315 syscallarg(int) shmflag; 316 } */ *uap; 317 int mode; 318 int segnum; 319 register_t *retval; 320 { 321 struct shmid_ds *shmseg; 322 struct ucred *cred = p->p_ucred; 323 int error; 324 325 shmseg = &shmsegs[segnum]; 326 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 327 /* 328 * This segment is in the process of being allocated. Wait 329 * until it's done, and look the key up again (in case the 330 * allocation failed or it was freed). 331 */ 332 shmseg->shm_perm.mode |= SHMSEG_WANTED; 333 if (error = 334 tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0)) 335 return error; 336 return EAGAIN; 337 } 338 if (error = ipcperm(cred, &shmseg->shm_perm, mode)) 339 return error; 340 if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz) 341 return EINVAL; 342 if (SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL) == 343 (IPC_CREAT | IPC_EXCL)) 344 return EEXIST; 345 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 346 return 0; 347 } 348 349 static int 350 shmget_allocate_segment(p, uap, mode, retval) 351 struct proc *p; 352 struct shmget_args /* { 353 syscallarg(key_t) key; 354 syscallarg(int) size; 355 syscallarg(int) shmflag; 356 } */ *uap; 357 int mode; 358 register_t *retval; 359 { 360 int i, segnum, result, shmid, size; 361 struct ucred *cred = p->p_ucred; 362 struct shmid_ds *shmseg; 363 struct shm_handle *shm_handle; 364 365 if (SCARG(uap, size) < shminfo.shmmin || 366 SCARG(uap, size) > shminfo.shmmax) 367 return EINVAL; 368 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 369 return ENOSPC; 370 size = (SCARG(uap, size) + CLOFSET) & ~CLOFSET; 371 if (shm_committed + btoc(size) > shminfo.shmall) 372 return ENOMEM; 373 if (shm_last_free < 0) { 374 for (i = 0; i < shminfo.shmmni; i++) 375 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 376 break; 377 if (i == shminfo.shmmni) 378 panic("shmseg free count inconsistent"); 379 segnum = i; 380 } else { 381 segnum = shm_last_free; 382 shm_last_free = -1; 383 } 384 shmseg = &shmsegs[segnum]; 385 /* 386 * In case we sleep in malloc(), mark the segment present but deleted 387 * so that noone else tries to create the same key. 388 */ 389 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 390 shmseg->shm_perm.key = SCARG(uap, key); 391 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 392 shm_handle = (struct shm_handle *) 393 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 394 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 395 result = vm_mmap(sysvshm_map, &shm_handle->kva, size, VM_PROT_ALL, 396 VM_PROT_DEFAULT, MAP_ANON, (caddr_t)(long)shmid, 0); 397 if (result != KERN_SUCCESS) { 398 shmseg->shm_perm.mode = SHMSEG_FREE; 399 shm_last_free = segnum; 400 free((caddr_t)shm_handle, M_SHM); 401 /* Just in case. */ 402 wakeup((caddr_t)shmseg); 403 return ENOMEM; 404 } 405 shmseg->shm_internal = shm_handle; 406 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 407 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 408 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 409 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 410 shmseg->shm_segsz = SCARG(uap, size); 411 shmseg->shm_cpid = p->p_pid; 412 shmseg->shm_lpid = shmseg->shm_nattch = 0; 413 shmseg->shm_atime = shmseg->shm_dtime = 0; 414 shmseg->shm_ctime = time.tv_sec; 415 shm_committed += btoc(size); 416 shm_nused++; 417 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 418 /* 419 * Somebody else wanted this key while we were asleep. Wake 420 * them up now. 421 */ 422 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 423 wakeup((caddr_t)shmseg); 424 } 425 *retval = shmid; 426 return 0; 427 } 428 429 int 430 shmget(p, uap, retval) 431 struct proc *p; 432 struct shmget_args /* { 433 syscallarg(key_t) key; 434 syscallarg(int) size; 435 syscallarg(int) shmflag; 436 } */ *uap; 437 register_t *retval; 438 { 439 int segnum, mode, error; 440 struct shmid_ds *shmseg; 441 442 mode = SCARG(uap, shmflg) & ACCESSPERMS; 443 if (SCARG(uap, key) != IPC_PRIVATE) { 444 again: 445 segnum = shm_find_segment_by_key(SCARG(uap, key)); 446 if (segnum >= 0) { 447 error = shmget_existing(p, uap, mode, segnum, retval); 448 if (error == EAGAIN) 449 goto again; 450 return error; 451 } 452 if ((SCARG(uap, shmflg) & IPC_CREAT) == 0) 453 return ENOENT; 454 } 455 return shmget_allocate_segment(p, uap, mode, retval); 456 } 457 458 void 459 shmfork(p1, p2, isvfork) 460 struct proc *p1, *p2; 461 int isvfork; 462 { 463 struct shmmap_state *shmmap_s; 464 size_t size; 465 int i; 466 467 size = shminfo.shmseg * sizeof(struct shmmap_state); 468 shmmap_s = malloc(size, M_SHM, M_WAITOK); 469 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size); 470 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s; 471 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 472 if (shmmap_s->shmid != -1) 473 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 474 } 475 476 void 477 shmexit(p) 478 struct proc *p; 479 { 480 struct shmmap_state *shmmap_s; 481 struct shmid_ds *shmseg; 482 int i; 483 484 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 485 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 486 if (shmmap_s->shmid != -1) 487 shm_delete_mapping(p, shmmap_s); 488 free((caddr_t)p->p_vmspace->vm_shm, M_SHM); 489 p->p_vmspace->vm_shm = NULL; 490 } 491 492 void 493 shminit() 494 { 495 int i; 496 vm_offset_t garbage1, garbage2; 497 498 shminfo.shmmax *= NBPG; 499 500 /* actually this *should* be pageable. SHM_{LOCK,UNLOCK} */ 501 sysvshm_map = kmem_suballoc(kernel_map, &garbage1, &garbage2, 502 shminfo.shmall * NBPG, TRUE); 503 for (i = 0; i < shminfo.shmmni; i++) { 504 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 505 shmsegs[i].shm_perm.seq = 0; 506 } 507 shm_last_free = 0; 508 shm_nused = 0; 509 shm_committed = 0; 510 } 511 512 #if defined(COMPAT_10) && !defined(alpha) || defined(COMPAT_SUNOS) 513 int 514 compat_10_shmsys(p, uap, retval) 515 struct proc *p; 516 struct compat_10_shmsys_args /* { 517 syscallarg(int) which; 518 syscallarg(int) a2; 519 syscallarg(int) a3; 520 syscallarg(int) a4; 521 } */ *uap; 522 register_t *retval; 523 { 524 struct shmat_args /* { 525 syscallarg(int) shmid; 526 syscallarg(void *) shmaddr; 527 syscallarg(int) shmflg; 528 } */ shmat_args; 529 struct shmctl_args /* { 530 syscallarg(int) shmid; 531 syscallarg(int) cmd; 532 syscallarg(struct shmid_ds *) buf; 533 } */ shmctl_args; 534 struct shmdt_args /* { 535 syscallarg(void *) shmaddr; 536 } */ shmdt_args; 537 struct shmget_args /* { 538 syscallarg(key_t) key; 539 syscallarg(int) size; 540 syscallarg(int) shmflg; 541 } */ shmget_args; 542 543 switch (SCARG(uap, which)) { 544 case 0: /* shmat() */ 545 SCARG(&shmat_args, shmid) = SCARG(uap, a2); 546 SCARG(&shmat_args, shmaddr) = (void *)SCARG(uap, a3); 547 SCARG(&shmat_args, shmflg) = SCARG(uap, a4); 548 return (shmat(p, &shmat_args, retval)); 549 550 case 1: /* shmctl() */ 551 SCARG(&shmctl_args, shmid) = SCARG(uap, a2); 552 SCARG(&shmctl_args, cmd) = SCARG(uap, a3); 553 SCARG(&shmctl_args, buf) = (struct shmid_ds *)SCARG(uap, a4); 554 return (shmctl(p, &shmctl_args, retval)); 555 556 case 2: /* shmdt() */ 557 SCARG(&shmat_args, shmaddr) = (void *)SCARG(uap, a2); 558 return (shmdt(p, &shmdt_args, retval)); 559 560 case 3: /* shmget() */ 561 SCARG(&shmget_args, key) = SCARG(uap, a2); 562 SCARG(&shmget_args, size) = SCARG(uap, a3); 563 SCARG(&shmget_args, shmflg) = SCARG(uap, a4); 564 return (shmget(p, &shmget_args, retval)); 565 566 default: 567 return (EINVAL); 568 } 569 } 570 #endif /* defined(COMPAT_10) && !defined(alpha) || defined(COMPAT_SUNOS) */ 571
Indexes created Tue Sep 30 20:09:53 GMT 2025