1 /* $FreeBSD: src/sys/kern/sysv_msg.c,v 1.23.2.5 2002/12/31 08:54:53 maxim Exp $ */ 2 3 /* 4 * Implementation of SVID messages 5 * 6 * Author: Daniel Boulet 7 * 8 * Copyright 1993 Daniel Boulet and RTMX Inc. 9 * 10 * This system call was implemented by Daniel Boulet under contract from RTMX. 11 * 12 * Redistribution and use in source forms, with and without modification, 13 * are permitted provided that this entire comment appears intact. 14 * 15 * Redistribution in binary form may occur without any restrictions. 16 * Obviously, it would be nice if you gave credit where credit is due 17 * but requiring it would be too onerous. 18 * 19 * This software is provided ``AS IS'' without any warranties of any kind. 20 */ 21 22 #include "opt_sysvipc.h" 23 24 #include <sys/param.h> 25 #include <sys/systm.h> 26 #include <sys/sysproto.h> 27 #include <sys/kernel.h> 28 #include <sys/proc.h> 29 #include <sys/priv.h> 30 #include <sys/msg.h> 31 #include <sys/sysent.h> 32 #include <sys/sysctl.h> 33 #include <sys/malloc.h> 34 #include <sys/jail.h> 35 36 #include <sys/mplock2.h> 37 38 static MALLOC_DEFINE(M_MSG, "msg", "SVID compatible message queues"); 39 40 static void msginit (void *); 41 42 #define MSG_DEBUG 43 #undef MSG_DEBUG_OK 44 45 static void msg_freehdr (struct msg *msghdr); 46 47 struct msg { 48 struct msg *msg_next; /* next msg in the chain */ 49 long msg_type; /* type of this message */ 50 /* >0 -> type of this message */ 51 /* 0 -> free header */ 52 u_short msg_ts; /* size of this message */ 53 short msg_spot; /* location of start of msg in buffer */ 54 }; 55 56 57 #ifndef MSGSSZ 58 #define MSGSSZ 8 /* Each segment must be 2^N long */ 59 #endif 60 #ifndef MSGSEG 61 #define MSGSEG 2048 /* must be less than 32767 */ 62 #endif 63 #define MSGMAX (MSGSSZ*MSGSEG) 64 #ifndef MSGMNB 65 #define MSGMNB 2048 /* max # of bytes in a queue */ 66 #endif 67 #ifndef MSGMNI 68 #define MSGMNI 40 69 #endif 70 #ifndef MSGTQL 71 #define MSGTQL 40 72 #endif 73 74 /* 75 * Based on the configuration parameters described in an SVR2 (yes, two) 76 * config(1m) man page. 77 * 78 * Each message is broken up and stored in segments that are msgssz bytes 79 * long. For efficiency reasons, this should be a power of two. Also, 80 * it doesn't make sense if it is less than 8 or greater than about 256. 81 * Consequently, msginit in kern/sysv_msg.c checks that msgssz is a power of 82 * two between 8 and 1024 inclusive (and panic's if it isn't). 83 */ 84 struct msginfo msginfo = { 85 MSGMAX, /* max chars in a message */ 86 MSGMNI, /* # of message queue identifiers */ 87 MSGMNB, /* max chars in a queue */ 88 MSGTQL, /* max messages in system */ 89 MSGSSZ, /* size of a message segment */ 90 /* (must be small power of 2 greater than 4) */ 91 MSGSEG /* number of message segments */ 92 }; 93 94 /* 95 * macros to convert between msqid_ds's and msqid's. 96 * (specific to this implementation) 97 */ 98 #define MSQID(ix,ds) ((ix) & 0xffff | (((ds).msg_perm.seq << 16) & 0xffff0000)) 99 #define MSQID_IX(id) ((id) & 0xffff) 100 #define MSQID_SEQ(id) (((id) >> 16) & 0xffff) 101 102 /* 103 * The rest of this file is specific to this particular implementation. 104 */ 105 106 struct msgmap { 107 short next; /* next segment in buffer */ 108 /* -1 -> available */ 109 /* 0..(MSGSEG-1) -> index of next segment */ 110 }; 111 112 #define MSG_LOCKED 01000 /* Is this msqid_ds locked? */ 113 114 static int nfree_msgmaps; /* # of free map entries */ 115 static short free_msgmaps; /* head of linked list of free map entries */ 116 static struct msg *free_msghdrs;/* list of free msg headers */ 117 static char *msgpool; /* MSGMAX byte long msg buffer pool */ 118 static struct msgmap *msgmaps; /* MSGSEG msgmap structures */ 119 static struct msg *msghdrs; /* MSGTQL msg headers */ 120 static struct msqid_ds *msqids; /* MSGMNI msqid_ds struct's */ 121 122 static void 123 msginit(void *dummy) 124 { 125 int i; 126 127 msginfo.msgmax = msginfo.msgseg * msginfo.msgssz; 128 msgpool = kmalloc(msginfo.msgmax, M_MSG, M_WAITOK); 129 msgmaps = kmalloc(sizeof(struct msgmap) * msginfo.msgseg, M_MSG, M_WAITOK); 130 msghdrs = kmalloc(sizeof(struct msg) * msginfo.msgtql, M_MSG, M_WAITOK); 131 msqids = kmalloc(sizeof(struct msqid_ds) * msginfo.msgmni, M_MSG, M_WAITOK); 132 133 /* 134 * msginfo.msgssz should be a power of two for efficiency reasons. 135 * It is also pretty silly if msginfo.msgssz is less than 8 136 * or greater than about 256 so ... 137 */ 138 139 i = 8; 140 while (i < 1024 && i != msginfo.msgssz) 141 i <<= 1; 142 if (i != msginfo.msgssz) { 143 kprintf("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz, 144 msginfo.msgssz); 145 panic("msginfo.msgssz not a small power of 2"); 146 } 147 148 if (msginfo.msgseg > 32767) { 149 kprintf("msginfo.msgseg=%d\n", msginfo.msgseg); 150 panic("msginfo.msgseg > 32767"); 151 } 152 153 for (i = 0; i < msginfo.msgseg; i++) { 154 if (i > 0) 155 msgmaps[i-1].next = i; 156 msgmaps[i].next = -1; /* implies entry is available */ 157 } 158 free_msgmaps = 0; 159 nfree_msgmaps = msginfo.msgseg; 160 161 for (i = 0; i < msginfo.msgtql; i++) { 162 msghdrs[i].msg_type = 0; 163 if (i > 0) 164 msghdrs[i-1].msg_next = &msghdrs[i]; 165 msghdrs[i].msg_next = NULL; 166 } 167 free_msghdrs = &msghdrs[0]; 168 169 for (i = 0; i < msginfo.msgmni; i++) { 170 msqids[i].msg_qbytes = 0; /* implies entry is available */ 171 msqids[i].msg_perm.seq = 0; /* reset to a known value */ 172 msqids[i].msg_perm.mode = 0; 173 } 174 } 175 SYSINIT(sysv_msg, SI_SUB_SYSV_MSG, SI_ORDER_FIRST, msginit, NULL); 176 177 static void 178 msg_freehdr(struct msg *msghdr) 179 { 180 while (msghdr->msg_ts > 0) { 181 short next; 182 if (msghdr->msg_spot < 0 || msghdr->msg_spot >= msginfo.msgseg) 183 panic("msghdr->msg_spot out of range"); 184 next = msgmaps[msghdr->msg_spot].next; 185 msgmaps[msghdr->msg_spot].next = free_msgmaps; 186 free_msgmaps = msghdr->msg_spot; 187 nfree_msgmaps++; 188 msghdr->msg_spot = next; 189 if (msghdr->msg_ts >= msginfo.msgssz) 190 msghdr->msg_ts -= msginfo.msgssz; 191 else 192 msghdr->msg_ts = 0; 193 } 194 if (msghdr->msg_spot != -1) 195 panic("msghdr->msg_spot != -1"); 196 msghdr->msg_next = free_msghdrs; 197 free_msghdrs = msghdr; 198 } 199 200 /* 201 * MPALMOSTSAFE 202 */ 203 int 204 sys_msgctl(struct msgctl_args *uap) 205 { 206 struct thread *td = curthread; 207 struct proc *p = td->td_proc; 208 int msqid = uap->msqid; 209 int cmd = uap->cmd; 210 struct msqid_ds *user_msqptr = uap->buf; 211 int rval, eval; 212 struct msqid_ds msqbuf; 213 struct msqid_ds *msqptr; 214 215 #ifdef MSG_DEBUG_OK 216 kprintf("call to msgctl(%d, %d, 0x%x)\n", msqid, cmd, user_msqptr); 217 #endif 218 219 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 220 return (ENOSYS); 221 222 get_mplock(); 223 msqid = IPCID_TO_IX(msqid); 224 225 if (msqid < 0 || msqid >= msginfo.msgmni) { 226 #ifdef MSG_DEBUG_OK 227 kprintf("msqid (%d) out of range (0<=msqid<%d)\n", msqid, 228 msginfo.msgmni); 229 #endif 230 eval = EINVAL; 231 goto done; 232 } 233 234 msqptr = &msqids[msqid]; 235 236 if (msqptr->msg_qbytes == 0) { 237 #ifdef MSG_DEBUG_OK 238 kprintf("no such msqid\n"); 239 #endif 240 eval = EINVAL; 241 goto done; 242 } 243 if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) { 244 #ifdef MSG_DEBUG_OK 245 kprintf("wrong sequence number\n"); 246 #endif 247 eval = EINVAL; 248 goto done; 249 } 250 251 rval = 0; 252 253 switch (cmd) { 254 case IPC_RMID: 255 { 256 struct msg *msghdr; 257 if ((eval = ipcperm(p, &msqptr->msg_perm, IPC_M)) != 0) 258 break; 259 /* Free the message headers */ 260 msghdr = msqptr->msg_first; 261 while (msghdr != NULL) { 262 struct msg *msghdr_tmp; 263 264 /* Free the segments of each message */ 265 msqptr->msg_cbytes -= msghdr->msg_ts; 266 msqptr->msg_qnum--; 267 msghdr_tmp = msghdr; 268 msghdr = msghdr->msg_next; 269 msg_freehdr(msghdr_tmp); 270 } 271 272 if (msqptr->msg_cbytes != 0) 273 panic("msg_cbytes is screwed up"); 274 if (msqptr->msg_qnum != 0) 275 panic("msg_qnum is screwed up"); 276 277 msqptr->msg_qbytes = 0; /* Mark it as free */ 278 279 wakeup((caddr_t)msqptr); 280 } 281 282 break; 283 284 case IPC_SET: 285 if ((eval = ipcperm(p, &msqptr->msg_perm, IPC_M)) != 0) 286 break; 287 if ((eval = copyin(user_msqptr, &msqbuf, sizeof(msqbuf))) != 0) 288 break; 289 if (msqbuf.msg_qbytes > msqptr->msg_qbytes) { 290 eval = priv_check(td, PRIV_ROOT); 291 if (eval) 292 break; 293 } 294 if (msqbuf.msg_qbytes > msginfo.msgmnb) { 295 #ifdef MSG_DEBUG_OK 296 kprintf("can't increase msg_qbytes beyond %d (truncating)\n", 297 msginfo.msgmnb); 298 #endif 299 msqbuf.msg_qbytes = msginfo.msgmnb; /* silently restrict qbytes to system limit */ 300 } 301 if (msqbuf.msg_qbytes == 0) { 302 #ifdef MSG_DEBUG_OK 303 kprintf("can't reduce msg_qbytes to 0\n"); 304 #endif 305 eval = EINVAL; /* non-standard errno! */ 306 break; 307 } 308 msqptr->msg_perm.uid = msqbuf.msg_perm.uid; /* change the owner */ 309 msqptr->msg_perm.gid = msqbuf.msg_perm.gid; /* change the owner */ 310 msqptr->msg_perm.mode = (msqptr->msg_perm.mode & ~0777) | 311 (msqbuf.msg_perm.mode & 0777); 312 msqptr->msg_qbytes = msqbuf.msg_qbytes; 313 msqptr->msg_ctime = time_second; 314 break; 315 316 case IPC_STAT: 317 if ((eval = ipcperm(p, &msqptr->msg_perm, IPC_R))) { 318 #ifdef MSG_DEBUG_OK 319 kprintf("requester doesn't have read access\n"); 320 #endif 321 eval = EINVAL; 322 break; 323 } 324 eval = copyout(msqptr, user_msqptr, sizeof(struct msqid_ds)); 325 break; 326 327 default: 328 #ifdef MSG_DEBUG_OK 329 kprintf("invalid command %d\n", cmd); 330 #endif 331 eval = EINVAL; 332 break; 333 } 334 done: 335 rel_mplock(); 336 if (eval == 0) 337 uap->sysmsg_result = rval; 338 return(eval); 339 } 340 341 /* 342 * MPALMOSTSAFE 343 */ 344 int 345 sys_msgget(struct msgget_args *uap) 346 { 347 struct thread *td = curthread; 348 int msqid, eval; 349 int key = uap->key; 350 int msgflg = uap->msgflg; 351 struct ucred *cred = td->td_ucred; 352 struct msqid_ds *msqptr = NULL; 353 354 #ifdef MSG_DEBUG_OK 355 kprintf("msgget(0x%x, 0%o)\n", key, msgflg); 356 #endif 357 if (!jail_sysvipc_allowed && cred->cr_prison != NULL) 358 return (ENOSYS); 359 360 eval = 0; 361 get_mplock(); 362 363 if (key != IPC_PRIVATE) { 364 for (msqid = 0; msqid < msginfo.msgmni; msqid++) { 365 msqptr = &msqids[msqid]; 366 if (msqptr->msg_qbytes != 0 && 367 msqptr->msg_perm.key == key) 368 break; 369 } 370 if (msqid < msginfo.msgmni) { 371 #ifdef MSG_DEBUG_OK 372 kprintf("found public key\n"); 373 #endif 374 if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) { 375 #ifdef MSG_DEBUG_OK 376 kprintf("not exclusive\n"); 377 #endif 378 eval = EEXIST; 379 goto done; 380 } 381 if ((eval = ipcperm(td->td_proc, &msqptr->msg_perm, msgflg & 0700 ))) { 382 #ifdef MSG_DEBUG_OK 383 kprintf("requester doesn't have 0%o access\n", 384 msgflg & 0700); 385 #endif 386 goto done; 387 } 388 goto done; 389 } 390 } 391 392 #ifdef MSG_DEBUG_OK 393 kprintf("need to allocate the msqid_ds\n"); 394 #endif 395 if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) { 396 for (msqid = 0; msqid < msginfo.msgmni; msqid++) { 397 /* 398 * Look for an unallocated and unlocked msqid_ds. 399 * msqid_ds's can be locked by msgsnd or msgrcv while 400 * they are copying the message in/out. We can't 401 * re-use the entry until they release it. 402 */ 403 msqptr = &msqids[msqid]; 404 if (msqptr->msg_qbytes == 0 && 405 (msqptr->msg_perm.mode & MSG_LOCKED) == 0) 406 break; 407 } 408 if (msqid == msginfo.msgmni) { 409 #ifdef MSG_DEBUG_OK 410 kprintf("no more msqid_ds's available\n"); 411 #endif 412 eval = ENOSPC; 413 goto done; 414 } 415 #ifdef MSG_DEBUG_OK 416 kprintf("msqid %d is available\n", msqid); 417 #endif 418 msqptr->msg_perm.key = key; 419 msqptr->msg_perm.cuid = cred->cr_uid; 420 msqptr->msg_perm.uid = cred->cr_uid; 421 msqptr->msg_perm.cgid = cred->cr_gid; 422 msqptr->msg_perm.gid = cred->cr_gid; 423 msqptr->msg_perm.mode = (msgflg & 0777); 424 /* Make sure that the returned msqid is unique */ 425 msqptr->msg_perm.seq = (msqptr->msg_perm.seq + 1) & 0x7fff; 426 msqptr->msg_first = NULL; 427 msqptr->msg_last = NULL; 428 msqptr->msg_cbytes = 0; 429 msqptr->msg_qnum = 0; 430 msqptr->msg_qbytes = msginfo.msgmnb; 431 msqptr->msg_lspid = 0; 432 msqptr->msg_lrpid = 0; 433 msqptr->msg_stime = 0; 434 msqptr->msg_rtime = 0; 435 msqptr->msg_ctime = time_second; 436 } else { 437 #ifdef MSG_DEBUG_OK 438 kprintf("didn't find it and wasn't asked to create it\n"); 439 #endif 440 eval = ENOENT; 441 } 442 443 done: 444 rel_mplock(); 445 /* Construct the unique msqid */ 446 if (eval == 0) 447 uap->sysmsg_result = IXSEQ_TO_IPCID(msqid, msqptr->msg_perm); 448 return(eval); 449 } 450 451 /* 452 * MPALMOSTSAFE 453 */ 454 int 455 sys_msgsnd(struct msgsnd_args *uap) 456 { 457 struct thread *td = curthread; 458 int msqid = uap->msqid; 459 const void *user_msgp = uap->msgp; 460 size_t msgsz = uap->msgsz; 461 int msgflg = uap->msgflg; 462 int segs_needed, eval; 463 struct msqid_ds *msqptr; 464 struct msg *msghdr; 465 short next; 466 467 #ifdef MSG_DEBUG_OK 468 kprintf("call to msgsnd(%d, 0x%x, %d, %d)\n", msqid, user_msgp, msgsz, 469 msgflg); 470 #endif 471 472 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 473 return (ENOSYS); 474 475 get_mplock(); 476 msqid = IPCID_TO_IX(msqid); 477 478 if (msqid < 0 || msqid >= msginfo.msgmni) { 479 #ifdef MSG_DEBUG_OK 480 kprintf("msqid (%d) out of range (0<=msqid<%d)\n", msqid, 481 msginfo.msgmni); 482 #endif 483 eval = EINVAL; 484 goto done; 485 } 486 487 msqptr = &msqids[msqid]; 488 if (msqptr->msg_qbytes == 0) { 489 #ifdef MSG_DEBUG_OK 490 kprintf("no such message queue id\n"); 491 #endif 492 eval = EINVAL; 493 goto done; 494 } 495 if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) { 496 #ifdef MSG_DEBUG_OK 497 kprintf("wrong sequence number\n"); 498 #endif 499 eval = EINVAL; 500 goto done; 501 } 502 503 if ((eval = ipcperm(td->td_proc, &msqptr->msg_perm, IPC_W))) { 504 #ifdef MSG_DEBUG_OK 505 kprintf("requester doesn't have write access\n"); 506 #endif 507 eval = EINVAL; 508 goto done; 509 } 510 511 segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz; 512 #ifdef MSG_DEBUG_OK 513 kprintf("msgsz=%d, msgssz=%d, segs_needed=%d\n", msgsz, msginfo.msgssz, 514 segs_needed); 515 #endif 516 for (;;) { 517 int need_more_resources = 0; 518 519 /* 520 * check msgsz 521 * (inside this loop in case msg_qbytes changes while we sleep) 522 */ 523 524 if (msgsz > msqptr->msg_qbytes) { 525 #ifdef MSG_DEBUG_OK 526 kprintf("msgsz > msqptr->msg_qbytes\n"); 527 #endif 528 eval = EINVAL; 529 goto done; 530 } 531 532 if (msqptr->msg_perm.mode & MSG_LOCKED) { 533 #ifdef MSG_DEBUG_OK 534 kprintf("msqid is locked\n"); 535 #endif 536 need_more_resources = 1; 537 } 538 if (msgsz + msqptr->msg_cbytes > msqptr->msg_qbytes) { 539 #ifdef MSG_DEBUG_OK 540 kprintf("msgsz + msg_cbytes > msg_qbytes\n"); 541 #endif 542 need_more_resources = 1; 543 } 544 if (segs_needed > nfree_msgmaps) { 545 #ifdef MSG_DEBUG_OK 546 kprintf("segs_needed > nfree_msgmaps\n"); 547 #endif 548 need_more_resources = 1; 549 } 550 if (free_msghdrs == NULL) { 551 #ifdef MSG_DEBUG_OK 552 kprintf("no more msghdrs\n"); 553 #endif 554 need_more_resources = 1; 555 } 556 557 if (need_more_resources) { 558 int we_own_it; 559 560 if ((msgflg & IPC_NOWAIT) != 0) { 561 #ifdef MSG_DEBUG_OK 562 kprintf("need more resources but caller doesn't want to wait\n"); 563 #endif 564 eval = EAGAIN; 565 goto done; 566 } 567 568 if ((msqptr->msg_perm.mode & MSG_LOCKED) != 0) { 569 #ifdef MSG_DEBUG_OK 570 kprintf("we don't own the msqid_ds\n"); 571 #endif 572 we_own_it = 0; 573 } else { 574 /* Force later arrivals to wait for our 575 request */ 576 #ifdef MSG_DEBUG_OK 577 kprintf("we own the msqid_ds\n"); 578 #endif 579 msqptr->msg_perm.mode |= MSG_LOCKED; 580 we_own_it = 1; 581 } 582 #ifdef MSG_DEBUG_OK 583 kprintf("goodnight\n"); 584 #endif 585 eval = tsleep((caddr_t)msqptr, PCATCH, "msgwait", 0); 586 #ifdef MSG_DEBUG_OK 587 kprintf("good morning, eval=%d\n", eval); 588 #endif 589 if (we_own_it) 590 msqptr->msg_perm.mode &= ~MSG_LOCKED; 591 if (eval != 0) { 592 #ifdef MSG_DEBUG_OK 593 kprintf("msgsnd: interrupted system call\n"); 594 #endif 595 eval = EINTR; 596 goto done; 597 } 598 599 /* 600 * Make sure that the msq queue still exists 601 */ 602 603 if (msqptr->msg_qbytes == 0) { 604 #ifdef MSG_DEBUG_OK 605 kprintf("msqid deleted\n"); 606 #endif 607 eval = EIDRM; 608 goto done; 609 } 610 611 } else { 612 #ifdef MSG_DEBUG_OK 613 kprintf("got all the resources that we need\n"); 614 #endif 615 break; 616 } 617 } 618 619 /* 620 * We have the resources that we need. 621 * Make sure! 622 */ 623 624 if (msqptr->msg_perm.mode & MSG_LOCKED) 625 panic("msg_perm.mode & MSG_LOCKED"); 626 if (segs_needed > nfree_msgmaps) 627 panic("segs_needed > nfree_msgmaps"); 628 if (msgsz + msqptr->msg_cbytes > msqptr->msg_qbytes) 629 panic("msgsz + msg_cbytes > msg_qbytes"); 630 if (free_msghdrs == NULL) 631 panic("no more msghdrs"); 632 633 /* 634 * Re-lock the msqid_ds in case we page-fault when copying in the 635 * message 636 */ 637 638 if ((msqptr->msg_perm.mode & MSG_LOCKED) != 0) 639 panic("msqid_ds is already locked"); 640 msqptr->msg_perm.mode |= MSG_LOCKED; 641 642 /* 643 * Allocate a message header 644 */ 645 646 msghdr = free_msghdrs; 647 free_msghdrs = msghdr->msg_next; 648 msghdr->msg_spot = -1; 649 msghdr->msg_ts = msgsz; 650 651 /* 652 * Allocate space for the message 653 */ 654 655 while (segs_needed > 0) { 656 if (nfree_msgmaps <= 0) 657 panic("not enough msgmaps"); 658 if (free_msgmaps == -1) 659 panic("nil free_msgmaps"); 660 next = free_msgmaps; 661 if (next <= -1) 662 panic("next too low #1"); 663 if (next >= msginfo.msgseg) 664 panic("next out of range #1"); 665 #ifdef MSG_DEBUG_OK 666 kprintf("allocating segment %d to message\n", next); 667 #endif 668 free_msgmaps = msgmaps[next].next; 669 nfree_msgmaps--; 670 msgmaps[next].next = msghdr->msg_spot; 671 msghdr->msg_spot = next; 672 segs_needed--; 673 } 674 675 /* 676 * Copy in the message type 677 */ 678 679 if ((eval = copyin(user_msgp, &msghdr->msg_type, 680 sizeof(msghdr->msg_type))) != 0) { 681 #ifdef MSG_DEBUG_OK 682 kprintf("error %d copying the message type\n", eval); 683 #endif 684 msg_freehdr(msghdr); 685 msqptr->msg_perm.mode &= ~MSG_LOCKED; 686 wakeup((caddr_t)msqptr); 687 goto done; 688 } 689 user_msgp = (const char *)user_msgp + sizeof(msghdr->msg_type); 690 691 /* 692 * Validate the message type 693 */ 694 695 if (msghdr->msg_type < 1) { 696 msg_freehdr(msghdr); 697 msqptr->msg_perm.mode &= ~MSG_LOCKED; 698 wakeup((caddr_t)msqptr); 699 #ifdef MSG_DEBUG_OK 700 kprintf("mtype (%d) < 1\n", msghdr->msg_type); 701 #endif 702 eval = EINVAL; 703 goto done; 704 } 705 706 /* 707 * Copy in the message body 708 */ 709 710 next = msghdr->msg_spot; 711 while (msgsz > 0) { 712 size_t tlen; 713 if (msgsz > msginfo.msgssz) 714 tlen = msginfo.msgssz; 715 else 716 tlen = msgsz; 717 if (next <= -1) 718 panic("next too low #2"); 719 if (next >= msginfo.msgseg) 720 panic("next out of range #2"); 721 if ((eval = copyin(user_msgp, &msgpool[next * msginfo.msgssz], 722 tlen)) != 0) { 723 #ifdef MSG_DEBUG_OK 724 kprintf("error %d copying in message segment\n", eval); 725 #endif 726 msg_freehdr(msghdr); 727 msqptr->msg_perm.mode &= ~MSG_LOCKED; 728 wakeup((caddr_t)msqptr); 729 goto done; 730 } 731 msgsz -= tlen; 732 user_msgp = (const char *)user_msgp + tlen; 733 next = msgmaps[next].next; 734 } 735 if (next != -1) 736 panic("didn't use all the msg segments"); 737 738 /* 739 * We've got the message. Unlock the msqid_ds. 740 */ 741 742 msqptr->msg_perm.mode &= ~MSG_LOCKED; 743 744 /* 745 * Make sure that the msqid_ds is still allocated. 746 */ 747 748 if (msqptr->msg_qbytes == 0) { 749 msg_freehdr(msghdr); 750 wakeup((caddr_t)msqptr); 751 eval = EIDRM; 752 goto done; 753 } 754 755 /* 756 * Put the message into the queue 757 */ 758 759 if (msqptr->msg_first == NULL) { 760 msqptr->msg_first = msghdr; 761 msqptr->msg_last = msghdr; 762 } else { 763 msqptr->msg_last->msg_next = msghdr; 764 msqptr->msg_last = msghdr; 765 } 766 msqptr->msg_last->msg_next = NULL; 767 768 msqptr->msg_cbytes += msghdr->msg_ts; 769 msqptr->msg_qnum++; 770 msqptr->msg_lspid = td->td_proc->p_pid; 771 msqptr->msg_stime = time_second; 772 773 wakeup((caddr_t)msqptr); 774 eval = 0; 775 done: 776 rel_mplock(); 777 if (eval == 0) 778 uap->sysmsg_result = 0; 779 return (eval); 780 } 781 782 /* 783 * MPALMOSTSAFE 784 */ 785 int 786 sys_msgrcv(struct msgrcv_args *uap) 787 { 788 struct thread *td = curthread; 789 int msqid = uap->msqid; 790 void *user_msgp = uap->msgp; 791 size_t msgsz = uap->msgsz; 792 long msgtyp = uap->msgtyp; 793 int msgflg = uap->msgflg; 794 size_t len; 795 struct msqid_ds *msqptr; 796 struct msg *msghdr; 797 int eval; 798 short next; 799 800 #ifdef MSG_DEBUG_OK 801 kprintf("call to msgrcv(%d, 0x%x, %d, %ld, %d)\n", msqid, user_msgp, 802 msgsz, msgtyp, msgflg); 803 #endif 804 805 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 806 return (ENOSYS); 807 808 get_mplock(); 809 msqid = IPCID_TO_IX(msqid); 810 811 if (msqid < 0 || msqid >= msginfo.msgmni) { 812 #ifdef MSG_DEBUG_OK 813 kprintf("msqid (%d) out of range (0<=msqid<%d)\n", msqid, 814 msginfo.msgmni); 815 #endif 816 eval = EINVAL; 817 goto done; 818 } 819 820 msqptr = &msqids[msqid]; 821 if (msqptr->msg_qbytes == 0) { 822 #ifdef MSG_DEBUG_OK 823 kprintf("no such message queue id\n"); 824 #endif 825 eval = EINVAL; 826 goto done; 827 } 828 if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) { 829 #ifdef MSG_DEBUG_OK 830 kprintf("wrong sequence number\n"); 831 #endif 832 eval = EINVAL; 833 goto done; 834 } 835 836 if ((eval = ipcperm(td->td_proc, &msqptr->msg_perm, IPC_R))) { 837 #ifdef MSG_DEBUG_OK 838 kprintf("requester doesn't have read access\n"); 839 #endif 840 goto done; 841 } 842 843 msghdr = NULL; 844 while (msghdr == NULL) { 845 if (msgtyp == 0) { 846 msghdr = msqptr->msg_first; 847 if (msghdr != NULL) { 848 if (msgsz < msghdr->msg_ts && 849 (msgflg & MSG_NOERROR) == 0) { 850 #ifdef MSG_DEBUG_OK 851 kprintf("first message on the queue is too big (want %d, got %d)\n", 852 msgsz, msghdr->msg_ts); 853 #endif 854 eval = E2BIG; 855 goto done; 856 } 857 if (msqptr->msg_first == msqptr->msg_last) { 858 msqptr->msg_first = NULL; 859 msqptr->msg_last = NULL; 860 } else { 861 msqptr->msg_first = msghdr->msg_next; 862 if (msqptr->msg_first == NULL) 863 panic("msg_first/last screwed up #1"); 864 } 865 } 866 } else { 867 struct msg *previous; 868 struct msg **prev; 869 870 previous = NULL; 871 prev = &(msqptr->msg_first); 872 while ((msghdr = *prev) != NULL) { 873 /* 874 * Is this message's type an exact match or is 875 * this message's type less than or equal to 876 * the absolute value of a negative msgtyp? 877 * Note that the second half of this test can 878 * NEVER be true if msgtyp is positive since 879 * msg_type is always positive! 880 */ 881 882 if (msgtyp == msghdr->msg_type || 883 msghdr->msg_type <= -msgtyp) { 884 #ifdef MSG_DEBUG_OK 885 kprintf("found message type %d, requested %d\n", 886 msghdr->msg_type, msgtyp); 887 #endif 888 if (msgsz < msghdr->msg_ts && 889 (msgflg & MSG_NOERROR) == 0) { 890 #ifdef MSG_DEBUG_OK 891 kprintf("requested message on the queue is too big (want %d, got %d)\n", 892 msgsz, msghdr->msg_ts); 893 #endif 894 eval = E2BIG; 895 goto done; 896 } 897 *prev = msghdr->msg_next; 898 if (msghdr == msqptr->msg_last) { 899 if (previous == NULL) { 900 if (prev != 901 &msqptr->msg_first) 902 panic("msg_first/last screwed up #2"); 903 msqptr->msg_first = 904 NULL; 905 msqptr->msg_last = 906 NULL; 907 } else { 908 if (prev == 909 &msqptr->msg_first) 910 panic("msg_first/last screwed up #3"); 911 msqptr->msg_last = 912 previous; 913 } 914 } 915 break; 916 } 917 previous = msghdr; 918 prev = &(msghdr->msg_next); 919 } 920 } 921 922 /* 923 * We've either extracted the msghdr for the appropriate 924 * message or there isn't one. 925 * If there is one then bail out of this loop. 926 */ 927 928 if (msghdr != NULL) 929 break; 930 931 /* 932 * Hmph! No message found. Does the user want to wait? 933 */ 934 935 if ((msgflg & IPC_NOWAIT) != 0) { 936 #ifdef MSG_DEBUG_OK 937 kprintf("no appropriate message found (msgtyp=%d)\n", 938 msgtyp); 939 #endif 940 /* The SVID says to return ENOMSG. */ 941 #ifdef ENOMSG 942 eval = ENOMSG; 943 #else 944 /* Unfortunately, BSD doesn't define that code yet! */ 945 eval = EAGAIN; 946 #endif 947 goto done; 948 } 949 950 /* 951 * Wait for something to happen 952 */ 953 954 #ifdef MSG_DEBUG_OK 955 kprintf("msgrcv: goodnight\n"); 956 #endif 957 eval = tsleep((caddr_t)msqptr, PCATCH, "msgwait", 0); 958 #ifdef MSG_DEBUG_OK 959 kprintf("msgrcv: good morning (eval=%d)\n", eval); 960 #endif 961 962 if (eval != 0) { 963 #ifdef MSG_DEBUG_OK 964 kprintf("msgsnd: interrupted system call\n"); 965 #endif 966 eval = EINTR; 967 goto done; 968 } 969 970 /* 971 * Make sure that the msq queue still exists 972 */ 973 974 if (msqptr->msg_qbytes == 0 || 975 msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) { 976 #ifdef MSG_DEBUG_OK 977 kprintf("msqid deleted\n"); 978 #endif 979 eval = EIDRM; 980 goto done; 981 } 982 } 983 984 /* 985 * Return the message to the user. 986 * 987 * First, do the bookkeeping (before we risk being interrupted). 988 */ 989 990 msqptr->msg_cbytes -= msghdr->msg_ts; 991 msqptr->msg_qnum--; 992 msqptr->msg_lrpid = td->td_proc->p_pid; 993 msqptr->msg_rtime = time_second; 994 995 /* 996 * Make msgsz the actual amount that we'll be returning. 997 * Note that this effectively truncates the message if it is too long 998 * (since msgsz is never increased). 999 */ 1000 1001 #ifdef MSG_DEBUG_OK 1002 kprintf("found a message, msgsz=%d, msg_ts=%d\n", msgsz, 1003 msghdr->msg_ts); 1004 #endif 1005 if (msgsz > msghdr->msg_ts) 1006 msgsz = msghdr->msg_ts; 1007 1008 /* 1009 * Return the type to the user. 1010 */ 1011 1012 eval = copyout((caddr_t)&(msghdr->msg_type), user_msgp, 1013 sizeof(msghdr->msg_type)); 1014 if (eval != 0) { 1015 #ifdef MSG_DEBUG_OK 1016 kprintf("error (%d) copying out message type\n", eval); 1017 #endif 1018 msg_freehdr(msghdr); 1019 wakeup((caddr_t)msqptr); 1020 goto done; 1021 } 1022 user_msgp = (char *)user_msgp + sizeof(msghdr->msg_type); 1023 1024 /* 1025 * Return the segments to the user 1026 */ 1027 1028 next = msghdr->msg_spot; 1029 for (len = 0; len < msgsz; len += msginfo.msgssz) { 1030 size_t tlen; 1031 1032 if (msgsz - len > msginfo.msgssz) 1033 tlen = msginfo.msgssz; 1034 else 1035 tlen = msgsz - len; 1036 if (next <= -1) 1037 panic("next too low #3"); 1038 if (next >= msginfo.msgseg) 1039 panic("next out of range #3"); 1040 eval = copyout((caddr_t)&msgpool[next * msginfo.msgssz], 1041 user_msgp, tlen); 1042 if (eval != 0) { 1043 #ifdef MSG_DEBUG_OK 1044 kprintf("error (%d) copying out message segment\n", 1045 eval); 1046 #endif 1047 msg_freehdr(msghdr); 1048 wakeup((caddr_t)msqptr); 1049 goto done; 1050 } 1051 user_msgp = (char *)user_msgp + tlen; 1052 next = msgmaps[next].next; 1053 } 1054 1055 /* 1056 * Done, return the actual number of bytes copied out. 1057 */ 1058 1059 msg_freehdr(msghdr); 1060 wakeup((caddr_t)msqptr); 1061 eval = 0; 1062 done: 1063 rel_mplock(); 1064 if (eval == 0) 1065 uap->sysmsg_result = msgsz; 1066 return(eval); 1067 } 1068 1069 static int 1070 sysctl_msqids(SYSCTL_HANDLER_ARGS) 1071 { 1072 1073 return (SYSCTL_OUT(req, msqids, 1074 sizeof(struct msqid_ds) * msginfo.msgmni)); 1075 } 1076 1077 TUNABLE_INT("kern.ipc.msgseg", &msginfo.msgseg); 1078 TUNABLE_INT("kern.ipc.msgssz", &msginfo.msgssz); 1079 TUNABLE_INT("kern.ipc.msgmni", &msginfo.msgmni); 1080 1081 SYSCTL_INT(_kern_ipc, OID_AUTO, msgmax, CTLFLAG_RD, &msginfo.msgmax, 0, 1082 "Max characters in message"); 1083 SYSCTL_INT(_kern_ipc, OID_AUTO, msgmni, CTLFLAG_RD, &msginfo.msgmni, 0, 1084 "Max message queue identifiers"); 1085 SYSCTL_INT(_kern_ipc, OID_AUTO, msgmnb, CTLFLAG_RD, &msginfo.msgmnb, 0, 1086 "Max characters in message queue"); 1087 SYSCTL_INT(_kern_ipc, OID_AUTO, msgtql, CTLFLAG_RD, &msginfo.msgtql, 0, 1088 "Max SVID messages in system"); 1089 SYSCTL_INT(_kern_ipc, OID_AUTO, msgssz, CTLFLAG_RD, &msginfo.msgssz, 0, 1090 "Power-of-two size of a message segment"); 1091 SYSCTL_INT(_kern_ipc, OID_AUTO, msgseg, CTLFLAG_RD, &msginfo.msgseg, 0, 1092 "Number of message segments"); 1093 SYSCTL_PROC(_kern_ipc, OID_AUTO, msqids, CTLFLAG_RD, 1094 NULL, 0, sysctl_msqids, "", "Message queue IDs"); 1095