sysv_shm.c revision 1.34
1 /* $NetBSD: sysv_shm.c,v 1.34 1995/12/09 04:12:56 mycroft 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 *) 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 sys_shmdt(p, v, retval) 163 struct proc *p; 164 void *v; 165 register_t *retval; 166 { 167 struct sys_shmdt_args /* { 168 syscallarg(void *) shmaddr; 169 } */ *uap = v; 170 struct shmmap_state *shmmap_s; 171 int i; 172 173 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 174 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 175 if (shmmap_s->shmid != -1 && 176 shmmap_s->va == (vm_offset_t)SCARG(uap, shmaddr)) 177 break; 178 if (i == shminfo.shmseg) 179 return EINVAL; 180 return shm_delete_mapping(p, shmmap_s); 181 } 182 183 int 184 sys_shmat(p, v, retval) 185 struct proc *p; 186 void *v; 187 register_t *retval; 188 { 189 struct sys_shmat_args /* { 190 syscallarg(int) shmid; 191 syscallarg(void *) shmaddr; 192 syscallarg(int) shmflag; 193 } */ *uap = v; 194 int error, i, flags; 195 struct ucred *cred = p->p_ucred; 196 struct shmid_ds *shmseg; 197 struct shmmap_state *shmmap_s = NULL; 198 vm_offset_t attach_va; 199 vm_prot_t prot; 200 vm_size_t size; 201 202 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 203 if (shmmap_s == NULL) { 204 size = shminfo.shmseg * sizeof(struct shmmap_state); 205 shmmap_s = malloc(size, M_SHM, M_WAITOK); 206 for (i = 0; i < shminfo.shmseg; i++) 207 shmmap_s[i].shmid = -1; 208 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 209 } 210 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 211 if (shmseg == NULL) 212 return EINVAL; 213 if (error = ipcperm(cred, &shmseg->shm_perm, 214 (SCARG(uap, shmflg) & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W)) 215 return error; 216 for (i = 0; i < shminfo.shmseg; i++) { 217 if (shmmap_s->shmid == -1) 218 break; 219 shmmap_s++; 220 } 221 if (i >= shminfo.shmseg) 222 return EMFILE; 223 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 224 prot = VM_PROT_READ; 225 if ((SCARG(uap, shmflg) & SHM_RDONLY) == 0) 226 prot |= VM_PROT_WRITE; 227 flags = MAP_ANON | MAP_SHARED; 228 if (SCARG(uap, shmaddr)) { 229 flags |= MAP_FIXED; 230 if (SCARG(uap, shmflg) & SHM_RND) 231 attach_va = 232 (vm_offset_t)SCARG(uap, shmaddr) & ~(SHMLBA-1); 233 else if (((vm_offset_t)SCARG(uap, shmaddr) & (SHMLBA-1)) == 0) 234 attach_va = (vm_offset_t)SCARG(uap, shmaddr); 235 else 236 return EINVAL; 237 } else { 238 /* This is just a hint to vm_mmap() about where to put it. */ 239 attach_va = 240 round_page(p->p_vmspace->vm_taddr + MAXTSIZ + MAXDSIZ); 241 } 242 error = vm_mmap(&p->p_vmspace->vm_map, &attach_va, size, prot, 243 VM_PROT_DEFAULT, flags, (caddr_t)(long)SCARG(uap, shmid), 0); 244 if (error) 245 return error; 246 shmmap_s->va = attach_va; 247 shmmap_s->shmid = SCARG(uap, shmid); 248 shmseg->shm_lpid = p->p_pid; 249 shmseg->shm_atime = time.tv_sec; 250 shmseg->shm_nattch++; 251 *retval = attach_va; 252 return 0; 253 } 254 255 int 256 sys_shmctl(p, v, retval) 257 struct proc *p; 258 void *v; 259 register_t *retval; 260 { 261 struct sys_shmctl_args /* { 262 syscallarg(int) shmid; 263 syscallarg(int) cmd; 264 syscallarg(struct shmid_ds *) buf; 265 } */ *uap = v; 266 int error, segnum; 267 struct ucred *cred = p->p_ucred; 268 struct shmid_ds inbuf; 269 struct shmid_ds *shmseg; 270 271 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 272 if (shmseg == NULL) 273 return EINVAL; 274 switch (SCARG(uap, cmd)) { 275 case IPC_STAT: 276 if (error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) 277 return error; 278 if (error = copyout((caddr_t)shmseg, SCARG(uap, buf), 279 sizeof(inbuf))) 280 return error; 281 break; 282 case IPC_SET: 283 if (error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) 284 return error; 285 if (error = copyin(SCARG(uap, buf), (caddr_t)&inbuf, 286 sizeof(inbuf))) 287 return error; 288 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 289 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 290 shmseg->shm_perm.mode = 291 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 292 (inbuf.shm_perm.mode & ACCESSPERMS); 293 shmseg->shm_ctime = time.tv_sec; 294 break; 295 case IPC_RMID: 296 if (error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) 297 return error; 298 shmseg->shm_perm.key = IPC_PRIVATE; 299 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 300 if (shmseg->shm_nattch <= 0) { 301 shm_deallocate_segment(shmseg); 302 shm_last_free = IPCID_TO_IX(SCARG(uap, shmid)); 303 } 304 break; 305 case SHM_LOCK: 306 case SHM_UNLOCK: 307 default: 308 return EINVAL; 309 } 310 return 0; 311 } 312 313 static int 314 shmget_existing(p, uap, mode, segnum, retval) 315 struct proc *p; 316 struct sys_shmget_args /* { 317 syscallarg(key_t) key; 318 syscallarg(int) size; 319 syscallarg(int) shmflag; 320 } */ *uap; 321 int mode; 322 int segnum; 323 register_t *retval; 324 { 325 struct shmid_ds *shmseg; 326 struct ucred *cred = p->p_ucred; 327 int error; 328 329 shmseg = &shmsegs[segnum]; 330 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 331 /* 332 * This segment is in the process of being allocated. Wait 333 * until it's done, and look the key up again (in case the 334 * allocation failed or it was freed). 335 */ 336 shmseg->shm_perm.mode |= SHMSEG_WANTED; 337 if (error = 338 tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0)) 339 return error; 340 return EAGAIN; 341 } 342 if (error = ipcperm(cred, &shmseg->shm_perm, mode)) 343 return error; 344 if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz) 345 return EINVAL; 346 if (SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL) == 347 (IPC_CREAT | IPC_EXCL)) 348 return EEXIST; 349 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 350 return 0; 351 } 352 353 static int 354 shmget_allocate_segment(p, uap, mode, retval) 355 struct proc *p; 356 struct sys_shmget_args /* { 357 syscallarg(key_t) key; 358 syscallarg(int) size; 359 syscallarg(int) shmflag; 360 } */ *uap; 361 int mode; 362 register_t *retval; 363 { 364 int i, segnum, result, shmid, size; 365 struct ucred *cred = p->p_ucred; 366 struct shmid_ds *shmseg; 367 struct shm_handle *shm_handle; 368 369 if (SCARG(uap, size) < shminfo.shmmin || 370 SCARG(uap, size) > shminfo.shmmax) 371 return EINVAL; 372 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 373 return ENOSPC; 374 size = (SCARG(uap, size) + CLOFSET) & ~CLOFSET; 375 if (shm_committed + btoc(size) > shminfo.shmall) 376 return ENOMEM; 377 if (shm_last_free < 0) { 378 for (i = 0; i < shminfo.shmmni; i++) 379 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 380 break; 381 if (i == shminfo.shmmni) 382 panic("shmseg free count inconsistent"); 383 segnum = i; 384 } else { 385 segnum = shm_last_free; 386 shm_last_free = -1; 387 } 388 shmseg = &shmsegs[segnum]; 389 /* 390 * In case we sleep in malloc(), mark the segment present but deleted 391 * so that noone else tries to create the same key. 392 */ 393 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 394 shmseg->shm_perm.key = SCARG(uap, key); 395 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 396 shm_handle = (struct shm_handle *) 397 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 398 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 399 result = vm_mmap(sysvshm_map, &shm_handle->kva, size, VM_PROT_ALL, 400 VM_PROT_DEFAULT, MAP_ANON, (caddr_t)(long)shmid, 0); 401 if (result != KERN_SUCCESS) { 402 shmseg->shm_perm.mode = SHMSEG_FREE; 403 shm_last_free = segnum; 404 free((caddr_t)shm_handle, M_SHM); 405 /* Just in case. */ 406 wakeup((caddr_t)shmseg); 407 return ENOMEM; 408 } 409 shmseg->shm_internal = shm_handle; 410 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 411 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 412 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 413 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 414 shmseg->shm_segsz = SCARG(uap, size); 415 shmseg->shm_cpid = p->p_pid; 416 shmseg->shm_lpid = shmseg->shm_nattch = 0; 417 shmseg->shm_atime = shmseg->shm_dtime = 0; 418 shmseg->shm_ctime = time.tv_sec; 419 shm_committed += btoc(size); 420 shm_nused++; 421 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 422 /* 423 * Somebody else wanted this key while we were asleep. Wake 424 * them up now. 425 */ 426 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 427 wakeup((caddr_t)shmseg); 428 } 429 *retval = shmid; 430 return 0; 431 } 432 433 int 434 sys_shmget(p, v, retval) 435 struct proc *p; 436 void *v; 437 register_t *retval; 438 { 439 struct sys_shmget_args /* { 440 syscallarg(key_t) key; 441 syscallarg(int) size; 442 syscallarg(int) shmflag; 443 } */ *uap = v; 444 int segnum, mode, error; 445 struct shmid_ds *shmseg; 446 447 mode = SCARG(uap, shmflg) & ACCESSPERMS; 448 if (SCARG(uap, key) != IPC_PRIVATE) { 449 again: 450 segnum = shm_find_segment_by_key(SCARG(uap, key)); 451 if (segnum >= 0) { 452 error = shmget_existing(p, uap, mode, segnum, retval); 453 if (error == EAGAIN) 454 goto again; 455 return error; 456 } 457 if ((SCARG(uap, shmflg) & IPC_CREAT) == 0) 458 return ENOENT; 459 } 460 return shmget_allocate_segment(p, uap, mode, retval); 461 } 462 463 void 464 shmfork(p1, p2) 465 struct proc *p1, *p2; 466 { 467 struct shmmap_state *shmmap_s; 468 size_t size; 469 int i; 470 471 size = shminfo.shmseg * sizeof(struct shmmap_state); 472 shmmap_s = malloc(size, M_SHM, M_WAITOK); 473 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size); 474 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s; 475 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 476 if (shmmap_s->shmid != -1) 477 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 478 } 479 480 void 481 shmexit(p) 482 struct proc *p; 483 { 484 struct shmmap_state *shmmap_s; 485 struct shmid_ds *shmseg; 486 int i; 487 488 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 489 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 490 if (shmmap_s->shmid != -1) 491 shm_delete_mapping(p, shmmap_s); 492 free((caddr_t)p->p_vmspace->vm_shm, M_SHM); 493 p->p_vmspace->vm_shm = NULL; 494 } 495 496 void 497 shminit() 498 { 499 int i; 500 vm_offset_t garbage1, garbage2; 501 502 shminfo.shmmax *= NBPG; 503 504 /* actually this *should* be pageable. SHM_{LOCK,UNLOCK} */ 505 sysvshm_map = kmem_suballoc(kernel_map, &garbage1, &garbage2, 506 shminfo.shmall * NBPG, TRUE); 507 for (i = 0; i < shminfo.shmmni; i++) { 508 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 509 shmsegs[i].shm_perm.seq = 0; 510 } 511 shm_last_free = 0; 512 shm_nused = 0; 513 shm_committed = 0; 514 } 515
Indexes created Wed Sep 24 05:09:52 GMT 2025