sysv_msg.c revision 1.44.4.1
1 /* $NetBSD: sysv_msg.c,v 1.44.4.1 2006/09/11 18:47:17 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 1999 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /* 41 * Implementation of SVID messages 42 * 43 * Author: Daniel Boulet 44 * 45 * Copyright 1993 Daniel Boulet and RTMX Inc. 46 * 47 * This system call was implemented by Daniel Boulet under contract from RTMX. 48 * 49 * Redistribution and use in source forms, with and without modification, 50 * are permitted provided that this entire comment appears intact. 51 * 52 * Redistribution in binary form may occur without any restrictions. 53 * Obviously, it would be nice if you gave credit where credit is due 54 * but requiring it would be too onerous. 55 * 56 * This software is provided ``AS IS'' without any warranties of any kind. 57 */ 58 59 #include <sys/cdefs.h> 60 __KERNEL_RCSID(0, "$NetBSD: sysv_msg.c,v 1.44.4.1 2006/09/11 18:47:17 ad Exp $"); 61 62 #define SYSVMSG 63 64 #include <sys/param.h> 65 #include <sys/kernel.h> 66 #include <sys/msg.h> 67 #include <sys/sysctl.h> 68 #include <sys/mount.h> /* XXX for <sys/syscallargs.h> */ 69 #include <sys/sa.h> 70 #include <sys/syscallargs.h> 71 #include <sys/kauth.h> 72 #include <sys/mutex.h> 73 74 #define MSG_DEBUG 75 #undef MSG_DEBUG_OK 76 77 #ifdef MSG_DEBUG_OK 78 #define MSG_PRINTF(a) printf a 79 #else 80 #define MSG_PRINTF(a) 81 #endif 82 83 static int nfree_msgmaps; /* # of free map entries */ 84 static short free_msgmaps; /* head of linked list of free map entries */ 85 static struct __msg *free_msghdrs; /* list of free msg headers */ 86 static char *msgpool; /* MSGMAX byte long msg buffer pool */ 87 static struct msgmap *msgmaps; /* MSGSEG msgmap structures */ 88 static struct __msg *msghdrs; /* MSGTQL msg headers */ 89 struct msqid_ds *msqids; /* MSGMNI msqid_ds struct's */ 90 static kmutex_t msgmutex; 91 92 static void msg_freehdr(struct __msg *); 93 94 void 95 msginit(void) 96 { 97 int i, sz; 98 vaddr_t v; 99 100 /* 101 * msginfo.msgssz should be a power of two for efficiency reasons. 102 * It is also pretty silly if msginfo.msgssz is less than 8 103 * or greater than about 256 so ... 104 */ 105 106 i = 8; 107 while (i < 1024 && i != msginfo.msgssz) 108 i <<= 1; 109 if (i != msginfo.msgssz) { 110 MSG_PRINTF(("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz, 111 msginfo.msgssz)); 112 panic("msginfo.msgssz not a small power of 2"); 113 } 114 115 if (msginfo.msgseg > 32767) { 116 MSG_PRINTF(("msginfo.msgseg=%d\n", msginfo.msgseg)); 117 panic("msginfo.msgseg > 32767"); 118 } 119 120 /* Allocate pageable memory for our structures */ 121 sz = msginfo.msgmax 122 + msginfo.msgseg * sizeof(struct msgmap) 123 + msginfo.msgtql * sizeof(struct __msg) 124 + msginfo.msgmni * sizeof(struct msqid_ds); 125 v = uvm_km_alloc(kernel_map, round_page(sz), 0, 126 UVM_KMF_WIRED|UVM_KMF_ZERO); 127 if (v == 0) 128 panic("sysv_msg: cannot allocate memory"); 129 msgpool = (void *)v; 130 msgmaps = (void *) (msgpool + msginfo.msgmax); 131 msghdrs = (void *) (msgmaps + msginfo.msgseg); 132 msqids = (void *) (msghdrs + msginfo.msgtql); 133 134 for (i = 0; i < msginfo.msgseg; i++) { 135 if (i > 0) 136 msgmaps[i-1].next = i; 137 msgmaps[i].next = -1; /* implies entry is available */ 138 } 139 free_msgmaps = 0; 140 nfree_msgmaps = msginfo.msgseg; 141 142 if (msghdrs == NULL) 143 panic("msghdrs is NULL"); 144 145 for (i = 0; i < msginfo.msgtql; i++) { 146 msghdrs[i].msg_type = 0; 147 if (i > 0) 148 msghdrs[i-1].msg_next = &msghdrs[i]; 149 msghdrs[i].msg_next = NULL; 150 } 151 free_msghdrs = &msghdrs[0]; 152 153 if (msqids == NULL) 154 panic("msqids is NULL"); 155 156 for (i = 0; i < msginfo.msgmni; i++) { 157 msqids[i].msg_qbytes = 0; /* implies entry is available */ 158 msqids[i].msg_perm._seq = 0; /* reset to a known value */ 159 } 160 161 mutex_init(&msgmutex, MUTEX_DEFAULT, IPL_NONE); 162 } 163 164 static void 165 msg_freehdr(struct __msg *msghdr) 166 { 167 168 KASSERT(mutex_owned(&msgmutex)); 169 170 while (msghdr->msg_ts > 0) { 171 short next; 172 if (msghdr->msg_spot < 0 || msghdr->msg_spot >= msginfo.msgseg) 173 panic("msghdr->msg_spot out of range"); 174 next = msgmaps[msghdr->msg_spot].next; 175 msgmaps[msghdr->msg_spot].next = free_msgmaps; 176 free_msgmaps = msghdr->msg_spot; 177 nfree_msgmaps++; 178 msghdr->msg_spot = next; 179 if (msghdr->msg_ts >= msginfo.msgssz) 180 msghdr->msg_ts -= msginfo.msgssz; 181 else 182 msghdr->msg_ts = 0; 183 } 184 if (msghdr->msg_spot != -1) 185 panic("msghdr->msg_spot != -1"); 186 msghdr->msg_next = free_msghdrs; 187 free_msghdrs = msghdr; 188 } 189 190 int 191 sys___msgctl13(struct lwp *l, void *v, register_t *retval) 192 { 193 struct sys___msgctl13_args /* { 194 syscallarg(int) msqid; 195 syscallarg(int) cmd; 196 syscallarg(struct msqid_ds *) buf; 197 } */ *uap = v; 198 struct msqid_ds msqbuf; 199 int cmd, error; 200 201 cmd = SCARG(uap, cmd); 202 203 if (cmd == IPC_SET) { 204 error = copyin(SCARG(uap, buf), &msqbuf, sizeof(msqbuf)); 205 if (error) 206 return (error); 207 } 208 209 error = msgctl1(l, SCARG(uap, msqid), cmd, 210 (cmd == IPC_SET || cmd == IPC_STAT) ? &msqbuf : NULL); 211 212 if (error == 0 && cmd == IPC_STAT) 213 error = copyout(&msqbuf, SCARG(uap, buf), sizeof(msqbuf)); 214 215 return (error); 216 } 217 218 int 219 msgctl1(struct lwp *l, int msqid, int cmd, struct msqid_ds *msqbuf) 220 { 221 kauth_cred_t cred = l->l_cred; 222 struct msqid_ds *msqptr; 223 int error = 0, ix; 224 225 MSG_PRINTF(("call to msgctl1(%d, %d)\n", msqid, cmd)); 226 227 ix = IPCID_TO_IX(msqid); 228 229 mutex_enter(&msgmutex); 230 231 if (ix < 0 || ix >= msginfo.msgmni) { 232 MSG_PRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", ix, 233 msginfo.msgmni)); 234 error = EINVAL; 235 goto unlock; 236 } 237 238 msqptr = &msqids[ix]; 239 240 if (msqptr->msg_qbytes == 0) { 241 MSG_PRINTF(("no such msqid\n")); 242 error = EINVAL; 243 goto unlock; 244 } 245 if (msqptr->msg_perm._seq != IPCID_TO_SEQ(msqid)) { 246 MSG_PRINTF(("wrong sequence number\n")); 247 error = EINVAL; 248 goto unlock; 249 } 250 251 switch (cmd) { 252 case IPC_RMID: 253 { 254 struct __msg *msghdr; 255 if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_M)) != 0) 256 break; 257 /* Free the message headers */ 258 msghdr = msqptr->_msg_first; 259 while (msghdr != NULL) { 260 struct __msg *msghdr_tmp; 261 262 /* Free the segments of each message */ 263 msqptr->_msg_cbytes -= msghdr->msg_ts; 264 msqptr->msg_qnum--; 265 msghdr_tmp = msghdr; 266 msghdr = msghdr->msg_next; 267 msg_freehdr(msghdr_tmp); 268 } 269 270 if (msqptr->_msg_cbytes != 0) 271 panic("msg_cbytes is screwed up"); 272 if (msqptr->msg_qnum != 0) 273 panic("msg_qnum is screwed up"); 274 275 msqptr->msg_qbytes = 0; /* Mark it as free */ 276 277 wakeup(msqptr); 278 } 279 break; 280 281 case IPC_SET: 282 if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_M))) 283 return (error); 284 if (msqbuf->msg_qbytes > msqptr->msg_qbytes && 285 kauth_cred_geteuid(cred) != 0) 286 return (EPERM); 287 if (msqbuf->msg_qbytes > msginfo.msgmnb) { 288 MSG_PRINTF(("can't increase msg_qbytes beyond %d " 289 "(truncating)\n", msginfo.msgmnb)); 290 /* silently restrict qbytes to system limit */ 291 msqbuf->msg_qbytes = msginfo.msgmnb; 292 } 293 if (msqbuf->msg_qbytes == 0) { 294 MSG_PRINTF(("can't reduce msg_qbytes to 0\n")); 295 error = EINVAL; /* XXX non-standard errno! */ 296 break; 297 } 298 msqptr->msg_perm.uid = msqbuf->msg_perm.uid; 299 msqptr->msg_perm.gid = msqbuf->msg_perm.gid; 300 msqptr->msg_perm.mode = (msqptr->msg_perm.mode & ~0777) | 301 (msqbuf->msg_perm.mode & 0777); 302 msqptr->msg_qbytes = msqbuf->msg_qbytes; 303 msqptr->msg_ctime = time_second; 304 break; 305 306 case IPC_STAT: 307 if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_R))) { 308 MSG_PRINTF(("requester doesn't have read access\n")); 309 return (error); 310 } 311 memcpy(msqbuf, msqptr, sizeof(struct msqid_ds)); 312 break; 313 314 default: 315 MSG_PRINTF(("invalid command %d\n", cmd)); 316 error = EINVAL; 317 break; 318 } 319 320 unlock: 321 mutex_exit(&msgmutex); 322 return (error); 323 } 324 325 int 326 sys_msgget(struct lwp *l, void *v, register_t *retval) 327 { 328 struct sys_msgget_args /* { 329 syscallarg(key_t) key; 330 syscallarg(int) msgflg; 331 } */ *uap = v; 332 int msqid, error = 0; 333 int key = SCARG(uap, key); 334 int msgflg = SCARG(uap, msgflg); 335 kauth_cred_t cred = l->l_cred; 336 struct msqid_ds *msqptr = NULL; 337 338 mutex_enter(&msgmutex); 339 340 MSG_PRINTF(("msgget(0x%x, 0%o)\n", key, msgflg)); 341 342 if (key != IPC_PRIVATE) { 343 for (msqid = 0; msqid < msginfo.msgmni; msqid++) { 344 msqptr = &msqids[msqid]; 345 if (msqptr->msg_qbytes != 0 && 346 msqptr->msg_perm._key == key) 347 break; 348 } 349 if (msqid < msginfo.msgmni) { 350 MSG_PRINTF(("found public key\n")); 351 if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) { 352 MSG_PRINTF(("not exclusive\n")); 353 error = EEXIST; 354 goto unlock; 355 } 356 if ((error = ipcperm(cred, &msqptr->msg_perm, 357 msgflg & 0700 ))) { 358 MSG_PRINTF(("requester doesn't have 0%o access\n", 359 msgflg & 0700)); 360 goto unlock; 361 } 362 goto found; 363 } 364 } 365 366 MSG_PRINTF(("need to allocate the msqid_ds\n")); 367 if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) { 368 for (msqid = 0; msqid < msginfo.msgmni; msqid++) { 369 /* 370 * Look for an unallocated and unlocked msqid_ds. 371 * msqid_ds's can be locked by msgsnd or msgrcv while 372 * they are copying the message in/out. We can't 373 * re-use the entry until they release it. 374 */ 375 msqptr = &msqids[msqid]; 376 if (msqptr->msg_qbytes == 0 && 377 (msqptr->msg_perm.mode & MSG_LOCKED) == 0) 378 break; 379 } 380 if (msqid == msginfo.msgmni) { 381 MSG_PRINTF(("no more msqid_ds's available\n")); 382 error = ENOSPC; 383 goto unlock; 384 } 385 MSG_PRINTF(("msqid %d is available\n", msqid)); 386 msqptr->msg_perm._key = key; 387 msqptr->msg_perm.cuid = kauth_cred_geteuid(cred); 388 msqptr->msg_perm.uid = kauth_cred_geteuid(cred); 389 msqptr->msg_perm.cgid = kauth_cred_getegid(cred); 390 msqptr->msg_perm.gid = kauth_cred_getegid(cred); 391 msqptr->msg_perm.mode = (msgflg & 0777); 392 /* Make sure that the returned msqid is unique */ 393 msqptr->msg_perm._seq++; 394 msqptr->_msg_first = NULL; 395 msqptr->_msg_last = NULL; 396 msqptr->_msg_cbytes = 0; 397 msqptr->msg_qnum = 0; 398 msqptr->msg_qbytes = msginfo.msgmnb; 399 msqptr->msg_lspid = 0; 400 msqptr->msg_lrpid = 0; 401 msqptr->msg_stime = 0; 402 msqptr->msg_rtime = 0; 403 msqptr->msg_ctime = time_second; 404 } else { 405 MSG_PRINTF(("didn't find it and wasn't asked to create it\n")); 406 error = ENOENT; 407 goto unlock; 408 } 409 410 found: 411 /* Construct the unique msqid */ 412 *retval = IXSEQ_TO_IPCID(msqid, msqptr->msg_perm); 413 414 unlock: 415 mutex_exit(&msgmutex); 416 return (error); 417 } 418 419 int 420 sys_msgsnd(struct lwp *l, void *v, register_t *retval) 421 { 422 struct sys_msgsnd_args /* { 423 syscallarg(int) msqid; 424 syscallarg(const void *) msgp; 425 syscallarg(size_t) msgsz; 426 syscallarg(int) msgflg; 427 } */ *uap = v; 428 429 return msgsnd1(l, SCARG(uap, msqid), SCARG(uap, msgp), 430 SCARG(uap, msgsz), SCARG(uap, msgflg), sizeof(long), copyin); 431 } 432 433 int 434 msgsnd1(struct lwp *l, int msqidr, const char *user_msgp, size_t msgsz, 435 int msgflg, size_t typesz, copyin_t fetch_type) 436 { 437 int segs_needed, error = 0, msqid; 438 kauth_cred_t cred = l->l_cred; 439 struct msqid_ds *msqptr; 440 struct __msg *msghdr; 441 short next; 442 443 MSG_PRINTF(("call to msgsnd(%d, %p, %lld, %d)\n", msqid, user_msgp, 444 (long long)msgsz, msgflg)); 445 446 msqid = IPCID_TO_IX(msqidr); 447 448 mutex_enter(&msgmutex); 449 450 if (msqid < 0 || msqid >= msginfo.msgmni) { 451 MSG_PRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid, 452 msginfo.msgmni)); 453 error = EINVAL; 454 goto unlock; 455 } 456 457 msqptr = &msqids[msqid]; 458 if (msqptr->msg_qbytes == 0) { 459 MSG_PRINTF(("no such message queue id\n")); 460 error = EINVAL; 461 goto unlock; 462 } 463 if (msqptr->msg_perm._seq != IPCID_TO_SEQ(msqidr)) { 464 MSG_PRINTF(("wrong sequence number\n")); 465 error = EINVAL; 466 goto unlock; 467 } 468 469 if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_W))) { 470 MSG_PRINTF(("requester doesn't have write access\n")); 471 goto unlock; 472 } 473 474 segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz; 475 MSG_PRINTF(("msgsz=%lld, msgssz=%d, segs_needed=%d\n", 476 (long long)msgsz, msginfo.msgssz, segs_needed)); 477 for (;;) { 478 int need_more_resources = 0; 479 480 /* 481 * check msgsz [cannot be negative since it is unsigned] 482 * (inside this loop in case msg_qbytes changes while we sleep) 483 */ 484 485 if (msgsz > msqptr->msg_qbytes) { 486 MSG_PRINTF(("msgsz > msqptr->msg_qbytes\n")); 487 error = EINVAL; 488 goto unlock; 489 } 490 491 if (msqptr->msg_perm.mode & MSG_LOCKED) { 492 MSG_PRINTF(("msqid is locked\n")); 493 need_more_resources = 1; 494 } 495 if (msgsz + msqptr->_msg_cbytes > msqptr->msg_qbytes) { 496 MSG_PRINTF(("msgsz + msg_cbytes > msg_qbytes\n")); 497 need_more_resources = 1; 498 } 499 if (segs_needed > nfree_msgmaps) { 500 MSG_PRINTF(("segs_needed > nfree_msgmaps\n")); 501 need_more_resources = 1; 502 } 503 if (free_msghdrs == NULL) { 504 MSG_PRINTF(("no more msghdrs\n")); 505 need_more_resources = 1; 506 } 507 508 if (need_more_resources) { 509 int we_own_it; 510 511 if ((msgflg & IPC_NOWAIT) != 0) { 512 MSG_PRINTF(("need more resources but caller " 513 "doesn't want to wait\n")); 514 error = EAGAIN; 515 goto unlock; 516 } 517 518 if ((msqptr->msg_perm.mode & MSG_LOCKED) != 0) { 519 MSG_PRINTF(("we don't own the msqid_ds\n")); 520 we_own_it = 0; 521 } else { 522 /* Force later arrivals to wait for our 523 request */ 524 MSG_PRINTF(("we own the msqid_ds\n")); 525 msqptr->msg_perm.mode |= MSG_LOCKED; 526 we_own_it = 1; 527 } 528 MSG_PRINTF(("goodnight\n")); 529 error = mtsleep(msqptr, (PZERO - 4) | PCATCH, 530 "msgwait", 0, &msgmutex); 531 MSG_PRINTF(("good morning, error=%d\n", error)); 532 if (we_own_it) 533 msqptr->msg_perm.mode &= ~MSG_LOCKED; 534 if (error != 0) { 535 MSG_PRINTF(("msgsnd: interrupted system " 536 "call\n")); 537 error = EINTR; 538 goto unlock; 539 } 540 541 /* 542 * Make sure that the msq queue still exists 543 */ 544 545 if (msqptr->msg_qbytes == 0) { 546 MSG_PRINTF(("msqid deleted\n")); 547 error = EIDRM; 548 goto unlock; 549 } 550 } else { 551 MSG_PRINTF(("got all the resources that we need\n")); 552 break; 553 } 554 } 555 556 /* 557 * We have the resources that we need. 558 * Make sure! 559 */ 560 561 if (msqptr->msg_perm.mode & MSG_LOCKED) 562 panic("msg_perm.mode & MSG_LOCKED"); 563 if (segs_needed > nfree_msgmaps) 564 panic("segs_needed > nfree_msgmaps"); 565 if (msgsz + msqptr->_msg_cbytes > msqptr->msg_qbytes) 566 panic("msgsz + msg_cbytes > msg_qbytes"); 567 if (free_msghdrs == NULL) 568 panic("no more msghdrs"); 569 570 /* 571 * Re-lock the msqid_ds in case we page-fault when copying in the 572 * message 573 */ 574 575 if ((msqptr->msg_perm.mode & MSG_LOCKED) != 0) 576 panic("msqid_ds is already locked"); 577 msqptr->msg_perm.mode |= MSG_LOCKED; 578 579 /* 580 * Allocate a message header 581 */ 582 583 msghdr = free_msghdrs; 584 free_msghdrs = msghdr->msg_next; 585 msghdr->msg_spot = -1; 586 msghdr->msg_ts = msgsz; 587 588 /* 589 * Allocate space for the message 590 */ 591 592 while (segs_needed > 0) { 593 if (nfree_msgmaps <= 0) 594 panic("not enough msgmaps"); 595 if (free_msgmaps == -1) 596 panic("nil free_msgmaps"); 597 next = free_msgmaps; 598 if (next <= -1) 599 panic("next too low #1"); 600 if (next >= msginfo.msgseg) 601 panic("next out of range #1"); 602 MSG_PRINTF(("allocating segment %d to message\n", next)); 603 free_msgmaps = msgmaps[next].next; 604 nfree_msgmaps--; 605 msgmaps[next].next = msghdr->msg_spot; 606 msghdr->msg_spot = next; 607 segs_needed--; 608 } 609 610 /* 611 * Copy in the message type 612 */ 613 mutex_exit(&msgmutex); 614 error = (*fetch_type)(user_msgp, &msghdr->msg_type, typesz); 615 mutex_enter(&msgmutex); 616 if (error != 0) { 617 MSG_PRINTF(("error %d copying the message type\n", error)); 618 msg_freehdr(msghdr); 619 msqptr->msg_perm.mode &= ~MSG_LOCKED; 620 wakeup(msqptr); 621 goto unlock; 622 } 623 user_msgp += typesz; 624 625 /* 626 * Validate the message type 627 */ 628 629 if (msghdr->msg_type < 1) { 630 msg_freehdr(msghdr); 631 msqptr->msg_perm.mode &= ~MSG_LOCKED; 632 wakeup(msqptr); 633 MSG_PRINTF(("mtype (%ld) < 1\n", msghdr->msg_type)); 634 goto unlock; 635 } 636 637 /* 638 * Copy in the message body 639 */ 640 641 next = msghdr->msg_spot; 642 while (msgsz > 0) { 643 size_t tlen; 644 if (msgsz > msginfo.msgssz) 645 tlen = msginfo.msgssz; 646 else 647 tlen = msgsz; 648 if (next <= -1) 649 panic("next too low #2"); 650 if (next >= msginfo.msgseg) 651 panic("next out of range #2"); 652 mutex_exit(&msgmutex); 653 error = copyin(user_msgp, &msgpool[next * msginfo.msgssz], tlen); 654 mutex_enter(&msgmutex); 655 if (error != 0) { 656 MSG_PRINTF(("error %d copying in message segment\n", 657 error)); 658 msg_freehdr(msghdr); 659 msqptr->msg_perm.mode &= ~MSG_LOCKED; 660 wakeup(msqptr); 661 goto unlock; 662 } 663 msgsz -= tlen; 664 user_msgp += tlen; 665 next = msgmaps[next].next; 666 } 667 if (next != -1) 668 panic("didn't use all the msg segments"); 669 670 /* 671 * We've got the message. Unlock the msqid_ds. 672 */ 673 674 msqptr->msg_perm.mode &= ~MSG_LOCKED; 675 676 /* 677 * Make sure that the msqid_ds is still allocated. 678 */ 679 680 if (msqptr->msg_qbytes == 0) { 681 msg_freehdr(msghdr); 682 wakeup(msqptr); 683 error = EIDRM; 684 goto unlock; 685 } 686 687 /* 688 * Put the message into the queue 689 */ 690 691 if (msqptr->_msg_first == NULL) { 692 msqptr->_msg_first = msghdr; 693 msqptr->_msg_last = msghdr; 694 } else { 695 msqptr->_msg_last->msg_next = msghdr; 696 msqptr->_msg_last = msghdr; 697 } 698 msqptr->_msg_last->msg_next = NULL; 699 700 msqptr->_msg_cbytes += msghdr->msg_ts; 701 msqptr->msg_qnum++; 702 msqptr->msg_lspid = l->l_proc->p_pid; 703 msqptr->msg_stime = time_second; 704 705 wakeup(msqptr); 706 707 unlock: 708 mutex_exit(&msgmutex); 709 return error; 710 } 711 712 int 713 sys_msgrcv(struct lwp *l, void *v, register_t *retval) 714 { 715 struct sys_msgrcv_args /* { 716 syscallarg(int) msqid; 717 syscallarg(void *) msgp; 718 syscallarg(size_t) msgsz; 719 syscallarg(long) msgtyp; 720 syscallarg(int) msgflg; 721 } */ *uap = v; 722 723 return msgrcv1(l, SCARG(uap, msqid), SCARG(uap, msgp), 724 SCARG(uap, msgsz), SCARG(uap, msgtyp), SCARG(uap, msgflg), 725 sizeof(long), copyout, retval); 726 } 727 728 int 729 msgrcv1(struct lwp *l, int msqidr, char *user_msgp, size_t msgsz, long msgtyp, 730 int msgflg, size_t typesz, copyout_t put_type, register_t *retval) 731 { 732 size_t len; 733 kauth_cred_t cred = l->l_cred; 734 struct msqid_ds *msqptr; 735 struct __msg *msghdr; 736 int error = 0, msqid; 737 short next; 738 739 MSG_PRINTF(("call to msgrcv(%d, %p, %lld, %ld, %d)\n", msqid, 740 user_msgp, (long long)msgsz, msgtyp, msgflg)); 741 742 msqid = IPCID_TO_IX(msqidr); 743 744 mutex_enter(&msgmutex); 745 746 if (msqid < 0 || msqid >= msginfo.msgmni) { 747 MSG_PRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid, 748 msginfo.msgmni)); 749 error = EINVAL; 750 goto unlock; 751 } 752 753 msqptr = &msqids[msqid]; 754 if (msqptr->msg_qbytes == 0) { 755 MSG_PRINTF(("no such message queue id\n")); 756 error = EINVAL; 757 goto unlock; 758 } 759 if (msqptr->msg_perm._seq != IPCID_TO_SEQ(msqidr)) { 760 MSG_PRINTF(("wrong sequence number\n")); 761 error = EINVAL; 762 goto unlock; 763 } 764 765 if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_R))) { 766 MSG_PRINTF(("requester doesn't have read access\n")); 767 goto unlock; 768 } 769 770 #if 0 771 /* cannot happen, msgsz is unsigned */ 772 if (msgsz < 0) { 773 MSG_PRINTF(("msgsz < 0\n")); 774 error = EINVAL; 775 goto unlock; 776 } 777 #endif 778 779 msghdr = NULL; 780 while (msghdr == NULL) { 781 if (msgtyp == 0) { 782 msghdr = msqptr->_msg_first; 783 if (msghdr != NULL) { 784 if (msgsz < msghdr->msg_ts && 785 (msgflg & MSG_NOERROR) == 0) { 786 MSG_PRINTF(("first message on the " 787 "queue is too big " 788 "(want %lld, got %d)\n", 789 (long long)msgsz, msghdr->msg_ts)); 790 error = E2BIG; 791 goto unlock; 792 } 793 if (msqptr->_msg_first == msqptr->_msg_last) { 794 msqptr->_msg_first = NULL; 795 msqptr->_msg_last = NULL; 796 } else { 797 msqptr->_msg_first = msghdr->msg_next; 798 if (msqptr->_msg_first == NULL) 799 panic("msg_first/last screwed " 800 "up #1"); 801 } 802 } 803 } else { 804 struct __msg *previous; 805 struct __msg **prev; 806 807 for (previous = NULL, prev = &msqptr->_msg_first; 808 (msghdr = *prev) != NULL; 809 previous = msghdr, prev = &msghdr->msg_next) { 810 /* 811 * Is this message's type an exact match or is 812 * this message's type less than or equal to 813 * the absolute value of a negative msgtyp? 814 * Note that the second half of this test can 815 * NEVER be true if msgtyp is positive since 816 * msg_type is always positive! 817 */ 818 819 if (msgtyp == msghdr->msg_type || 820 msghdr->msg_type <= -msgtyp) { 821 MSG_PRINTF(("found message type %ld, " 822 "requested %ld\n", 823 msghdr->msg_type, msgtyp)); 824 if (msgsz < msghdr->msg_ts && 825 (msgflg & MSG_NOERROR) == 0) { 826 MSG_PRINTF(("requested message " 827 "on the queue is too big " 828 "(want %lld, got %d)\n", 829 (long long)msgsz, 830 msghdr->msg_ts)); 831 error = E2BIG; 832 goto unlock; 833 } 834 *prev = msghdr->msg_next; 835 if (msghdr == msqptr->_msg_last) { 836 if (previous == NULL) { 837 if (prev != 838 &msqptr->_msg_first) 839 panic("msg_first/last screwed up #2"); 840 msqptr->_msg_first = 841 NULL; 842 msqptr->_msg_last = 843 NULL; 844 } else { 845 if (prev == 846 &msqptr->_msg_first) 847 panic("msg_first/last screwed up #3"); 848 msqptr->_msg_last = 849 previous; 850 } 851 } 852 break; 853 } 854 } 855 } 856 857 /* 858 * We've either extracted the msghdr for the appropriate 859 * message or there isn't one. 860 * If there is one then bail out of this loop. 861 */ 862 863 if (msghdr != NULL) 864 break; 865 866 /* 867 * Hmph! No message found. Does the user want to wait? 868 */ 869 870 if ((msgflg & IPC_NOWAIT) != 0) { 871 MSG_PRINTF(("no appropriate message found (msgtyp=%ld)\n", 872 msgtyp)); 873 /* The SVID says to return ENOMSG. */ 874 #ifdef ENOMSG 875 error = ENOMSG; 876 #else 877 /* Unfortunately, BSD doesn't define that code yet! */ 878 error = EAGAIN; 879 #endif 880 goto unlock; 881 } 882 883 /* 884 * Wait for something to happen 885 */ 886 887 MSG_PRINTF(("msgrcv: goodnight\n")); 888 error = mtsleep(msqptr, (PZERO - 4) | PCATCH, "msgwait", 889 0, &msgmutex); 890 MSG_PRINTF(("msgrcv: good morning (error=%d)\n", error)); 891 892 if (error != 0) { 893 MSG_PRINTF(("msgsnd: interrupted system call\n")); 894 error = EINTR; 895 goto unlock; 896 } 897 898 /* 899 * Make sure that the msq queue still exists 900 */ 901 902 if (msqptr->msg_qbytes == 0 || 903 msqptr->msg_perm._seq != IPCID_TO_SEQ(msqidr)) { 904 MSG_PRINTF(("msqid deleted\n")); 905 error = EIDRM; 906 goto unlock; 907 } 908 } 909 910 /* 911 * Return the message to the user. 912 * 913 * First, do the bookkeeping (before we risk being interrupted). 914 */ 915 916 msqptr->_msg_cbytes -= msghdr->msg_ts; 917 msqptr->msg_qnum--; 918 msqptr->msg_lrpid = l->l_proc->p_pid; 919 msqptr->msg_rtime = time_second; 920 921 /* 922 * Make msgsz the actual amount that we'll be returning. 923 * Note that this effectively truncates the message if it is too long 924 * (since msgsz is never increased). 925 */ 926 927 MSG_PRINTF(("found a message, msgsz=%lld, msg_ts=%d\n", 928 (long long)msgsz, msghdr->msg_ts)); 929 if (msgsz > msghdr->msg_ts) 930 msgsz = msghdr->msg_ts; 931 932 /* 933 * Return the type to the user. 934 */ 935 mutex_exit(&msgmutex); 936 error = (*put_type)(&msghdr->msg_type, user_msgp, typesz); 937 mutex_enter(&msgmutex); 938 if (error != 0) { 939 MSG_PRINTF(("error (%d) copying out message type\n", error)); 940 msg_freehdr(msghdr); 941 wakeup(msqptr); 942 goto unlock; 943 } 944 user_msgp += typesz; 945 946 /* 947 * Return the segments to the user 948 */ 949 950 next = msghdr->msg_spot; 951 for (len = 0; len < msgsz; len += msginfo.msgssz) { 952 size_t tlen; 953 954 if (msgsz - len > msginfo.msgssz) 955 tlen = msginfo.msgssz; 956 else 957 tlen = msgsz - len; 958 if (next <= -1) 959 panic("next too low #3"); 960 if (next >= msginfo.msgseg) 961 panic("next out of range #3"); 962 mutex_exit(&msgmutex); 963 error = copyout(&msgpool[next * msginfo.msgssz], 964 user_msgp, tlen); 965 mutex_enter(&msgmutex); 966 if (error != 0) { 967 MSG_PRINTF(("error (%d) copying out message segment\n", 968 error)); 969 msg_freehdr(msghdr); 970 wakeup(msqptr); 971 goto unlock; 972 } 973 user_msgp += tlen; 974 next = msgmaps[next].next; 975 } 976 977 /* 978 * Done, return the actual number of bytes copied out. 979 */ 980 981 msg_freehdr(msghdr); 982 wakeup(msqptr); 983 *retval = msgsz; 984 985 unlock: 986 mutex_exit(&msgmutex); 987 return error; 988 } 989
Indexes created Wed Oct 01 13:09:50 GMT 2025