sysv_shm.c revision 1.26
1 /* $NetBSD: sysv_shm.c,v 1.26 1994/10/20 04:23:19 cgd 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 static 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 static 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 #if 0 302 case SHM_LOCK: 303 case SHM_UNLOCK: 304 #endif 305 default: 306 return EINVAL; 307 } 308 return 0; 309 } 310 311 static int 312 shmget_existing(p, uap, mode, segnum, retval) 313 struct proc *p; 314 struct shmget_args /* { 315 syscallarg(key_t) key; 316 syscallarg(int) size; 317 syscallarg(int) shmflag; 318 } */ *uap; 319 int mode; 320 int segnum; 321 register_t *retval; 322 { 323 struct shmid_ds *shmseg; 324 struct ucred *cred = p->p_ucred; 325 int error; 326 327 shmseg = &shmsegs[segnum]; 328 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 329 /* 330 * This segment is in the process of being allocated. Wait 331 * until it's done, and look the key up again (in case the 332 * allocation failed or it was freed). 333 */ 334 shmseg->shm_perm.mode |= SHMSEG_WANTED; 335 if (error = 336 tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0)) 337 return error; 338 return EAGAIN; 339 } 340 if (error = ipcperm(cred, &shmseg->shm_perm, mode)) 341 return error; 342 if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz) 343 return EINVAL; 344 if (SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL) == 345 (IPC_CREAT | IPC_EXCL)) 346 return EEXIST; 347 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 348 return 0; 349 } 350 351 static int 352 shmget_allocate_segment(p, uap, mode, retval) 353 struct proc *p; 354 struct shmget_args /* { 355 syscallarg(key_t) key; 356 syscallarg(int) size; 357 syscallarg(int) shmflag; 358 } */ *uap; 359 int mode; 360 register_t *retval; 361 { 362 int i, segnum, result, shmid, size; 363 struct ucred *cred = p->p_ucred; 364 struct shmid_ds *shmseg; 365 struct shm_handle *shm_handle; 366 367 if (SCARG(uap, size) < shminfo.shmmin || 368 SCARG(uap, size) > shminfo.shmmax) 369 return EINVAL; 370 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 371 return ENOSPC; 372 size = (SCARG(uap, size) + CLOFSET) & ~CLOFSET; 373 if (shm_committed + btoc(size) > shminfo.shmall) 374 return ENOMEM; 375 if (shm_last_free < 0) { 376 for (i = 0; i < shminfo.shmmni; i++) 377 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 378 break; 379 if (i == shminfo.shmmni) 380 panic("shmseg free count inconsistent"); 381 segnum = i; 382 } else { 383 segnum = shm_last_free; 384 shm_last_free = -1; 385 } 386 shmseg = &shmsegs[segnum]; 387 /* 388 * In case we sleep in malloc(), mark the segment present but deleted 389 * so that noone else tries to create the same key. 390 */ 391 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 392 shmseg->shm_perm.key = SCARG(uap, key); 393 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 394 shm_handle = (struct shm_handle *) 395 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 396 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 397 result = vm_mmap(sysvshm_map, &shm_handle->kva, size, VM_PROT_ALL, 398 VM_PROT_DEFAULT, MAP_ANON, (caddr_t)(long)shmid, 0); 399 if (result != KERN_SUCCESS) { 400 shmseg->shm_perm.mode = SHMSEG_FREE; 401 shm_last_free = segnum; 402 free((caddr_t)shm_handle, M_SHM); 403 /* Just in case. */ 404 wakeup((caddr_t)shmseg); 405 return ENOMEM; 406 } 407 shmseg->shm_internal = shm_handle; 408 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 409 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 410 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 411 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 412 shmseg->shm_segsz = SCARG(uap, size); 413 shmseg->shm_cpid = p->p_pid; 414 shmseg->shm_lpid = shmseg->shm_nattch = 0; 415 shmseg->shm_atime = shmseg->shm_dtime = 0; 416 shmseg->shm_ctime = time.tv_sec; 417 shm_committed += btoc(size); 418 shm_nused++; 419 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 420 /* 421 * Somebody else wanted this key while we were asleep. Wake 422 * them up now. 423 */ 424 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 425 wakeup((caddr_t)shmseg); 426 } 427 *retval = shmid; 428 return 0; 429 } 430 431 int 432 shmget(p, uap, retval) 433 struct proc *p; 434 struct shmget_args /* { 435 syscallarg(key_t) key; 436 syscallarg(int) size; 437 syscallarg(int) shmflag; 438 } */ *uap; 439 register_t *retval; 440 { 441 int segnum, mode, error; 442 struct shmid_ds *shmseg; 443 444 mode = SCARG(uap, shmflg) & ACCESSPERMS; 445 if (SCARG(uap, key) != IPC_PRIVATE) { 446 again: 447 segnum = shm_find_segment_by_key(SCARG(uap, key)); 448 if (segnum >= 0) { 449 error = shmget_existing(p, uap, mode, segnum, retval); 450 if (error == EAGAIN) 451 goto again; 452 return error; 453 } 454 if ((SCARG(uap, shmflg) & IPC_CREAT) == 0) 455 return ENOENT; 456 } 457 return shmget_allocate_segment(p, uap, mode, retval); 458 } 459 460 void 461 shmfork(p1, p2, isvfork) 462 struct proc *p1, *p2; 463 int isvfork; 464 { 465 struct shmmap_state *shmmap_s; 466 size_t size; 467 int i; 468 469 size = shminfo.shmseg * sizeof(struct shmmap_state); 470 shmmap_s = malloc(size, M_SHM, M_WAITOK); 471 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size); 472 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s; 473 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 474 if (shmmap_s->shmid != -1) 475 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 476 } 477 478 void 479 shmexit(p) 480 struct proc *p; 481 { 482 struct shmmap_state *shmmap_s; 483 struct shmid_ds *shmseg; 484 int i; 485 486 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 487 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 488 if (shmmap_s->shmid != -1) 489 shm_delete_mapping(p, shmmap_s); 490 free((caddr_t)p->p_vmspace->vm_shm, M_SHM); 491 p->p_vmspace->vm_shm = NULL; 492 } 493 494 void 495 shminit() 496 { 497 int i; 498 vm_offset_t garbage1, garbage2; 499 500 shminfo.shmmax *= NBPG; 501 502 /* actually this *should* be pageable. SHM_{LOCK,UNLOCK} */ 503 sysvshm_map = kmem_suballoc(kernel_map, &garbage1, &garbage2, 504 shminfo.shmall * NBPG, TRUE); 505 for (i = 0; i < shminfo.shmmni; i++) { 506 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 507 shmsegs[i].shm_perm.seq = 0; 508 } 509 shm_last_free = 0; 510 shm_nused = 0; 511 shm_committed = 0; 512 } 513 514 #if defined(COMPAT_10) && !defined(alpha) 515 int 516 compat_10_shmsys(p, uap, retval) 517 struct proc *p; 518 struct compat_10_shmsys_args /* { 519 syscallarg(int) which; 520 syscallarg(int) a2; 521 syscallarg(int) a3; 522 syscallarg(int) a4; 523 } */ *uap; 524 register_t *retval; 525 { 526 struct shmat_args /* { 527 syscallarg(int) shmid; 528 syscallarg(void *) shmaddr; 529 syscallarg(int) shmflg; 530 } */ shmat_args; 531 struct shmctl_args /* { 532 syscallarg(int) shmid; 533 syscallarg(int) cmd; 534 syscallarg(struct shmid_ds *) buf; 535 } */ shmctl_args; 536 struct shmdt_args /* { 537 syscallarg(void *) shmaddr; 538 } */ shmdt_args; 539 struct shmget_args /* { 540 syscallarg(key_t) key; 541 syscallarg(int) size; 542 syscallarg(int) shmflg; 543 } */ shmget_args; 544 545 switch (SCARG(uap, which)) { 546 case 0: /* shmat() */ 547 SCARG(&shmat_args, shmid) = SCARG(uap, a2); 548 SCARG(&shmat_args, shmaddr) = (void *)SCARG(uap, a3); 549 SCARG(&shmat_args, shmflg) = SCARG(uap, a4); 550 return (shmat(p, &shmat_args, retval)); 551 552 case 1: /* shmctl() */ 553 SCARG(&shmctl_args, shmid) = SCARG(uap, a2); 554 SCARG(&shmctl_args, cmd) = SCARG(uap, a3); 555 SCARG(&shmctl_args, buf) = (struct shmid_ds *)SCARG(uap, a4); 556 return (shmctl(p, &shmctl_args, retval)); 557 558 case 2: /* shmdt() */ 559 SCARG(&shmat_args, shmaddr) = (void *)SCARG(uap, a2); 560 return (shmdt(p, &shmdt_args, retval)); 561 562 case 3: /* shmget() */ 563 SCARG(&shmget_args, key) = SCARG(uap, a2); 564 SCARG(&shmget_args, size) = SCARG(uap, a3); 565 SCARG(&shmget_args, shmflg) = SCARG(uap, a4); 566 return (shmget(p, &shmget_args, retval)); 567 568 default: 569 return (EINVAL); 570 } 571 } 572 #endif /* defined(COMPAT_10) && !defined(alpha) */ 573
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