1/*-
2 * Implementation of SVID messages
3 *
4 * Author: Daniel Boulet
5 *
6 * Copyright 1993 Daniel Boulet and RTMX Inc.
7 *
8 * This system call was implemented by Daniel Boulet under contract from RTMX.
9 *
10 * Redistribution and use in source forms, with and without modification,
11 * are permitted provided that this entire comment appears intact.
12 *
13 * Redistribution in binary form may occur without any restrictions.
14 * Obviously, it would be nice if you gave credit where credit is due
15 * but requiring it would be too onerous.
16 *
17 * This software is provided ``AS IS'' without any warranties of any kind.
18 */
19/*-
20 * Copyright (c) 2003-2005 McAfee, Inc.
21 * All rights reserved.
22 *
23 * This software was developed for the FreeBSD Project in part by McAfee
24 * Research, the Security Research Division of McAfee, Inc under DARPA/SPAWAR
25 * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research
26 * program.
27 *
28 * Redistribution and use in source and binary forms, with or without
29 * modification, are permitted provided that the following conditions
30 * are met:
31 * 1. Redistributions of source code must retain the above copyright
32 * notice, this list of conditions and the following disclaimer.
33 * 2. Redistributions in binary form must reproduce the above copyright
34 * notice, this list of conditions and the following disclaimer in the
35 * documentation and/or other materials provided with the distribution.
36 *
37 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
38 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
39 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
40 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
41 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
42 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
43 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
44 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
45 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
46 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
47 * SUCH DAMAGE.
48 */
49
50#include <sys/cdefs.h>
51__FBSDID("$FreeBSD: head/sys/kern/sysv_msg.c 193511 2009-06-05 14:55:22Z rwatson $");
52
53#include "opt_sysvipc.h"
54
55#include <sys/param.h>
56#include <sys/systm.h>
57#include <sys/sysproto.h>
58#include <sys/kernel.h>
59#include <sys/priv.h>
60#include <sys/proc.h>
61#include <sys/lock.h>
62#include <sys/mutex.h>
63#include <sys/module.h>
64#include <sys/msg.h>
65#include <sys/syscall.h>
66#include <sys/syscallsubr.h>
67#include <sys/sysent.h>
68#include <sys/sysctl.h>
69#include <sys/malloc.h>
70#include <sys/jail.h>
71
72#include <security/mac/mac_framework.h>
73
74static MALLOC_DEFINE(M_MSG, "msg", "SVID compatible message queues");
75
76static void msginit(void);
77static int msgunload(void);
78static int sysvmsg_modload(struct module *, int, void *);
79
80#ifdef MSG_DEBUG
81#define DPRINTF(a) printf a
82#else
83#define DPRINTF(a)
84#endif
85
86static void msg_freehdr(struct msg *msghdr);
87
88/* XXX casting to (sy_call_t *) is bogus, as usual. */
89static sy_call_t *msgcalls[] = {
90 (sy_call_t *)msgctl, (sy_call_t *)msgget,
91 (sy_call_t *)msgsnd, (sy_call_t *)msgrcv
92};
93
94#ifndef MSGSSZ
95#define MSGSSZ 8 /* Each segment must be 2^N long */
96#endif
97#ifndef MSGSEG
98#define MSGSEG 2048 /* must be less than 32767 */
99#endif
100#define MSGMAX (MSGSSZ*MSGSEG)
101#ifndef MSGMNB
102#define MSGMNB 2048 /* max # of bytes in a queue */
103#endif
104#ifndef MSGMNI
105#define MSGMNI 40
106#endif
107#ifndef MSGTQL
108#define MSGTQL 40
109#endif
110
111/*
112 * Based on the configuration parameters described in an SVR2 (yes, two)
113 * config(1m) man page.
114 *
115 * Each message is broken up and stored in segments that are msgssz bytes
116 * long. For efficiency reasons, this should be a power of two. Also,
117 * it doesn't make sense if it is less than 8 or greater than about 256.
118 * Consequently, msginit in kern/sysv_msg.c checks that msgssz is a power of
119 * two between 8 and 1024 inclusive (and panic's if it isn't).
120 */
121struct msginfo msginfo = {
122 MSGMAX, /* max chars in a message */
123 MSGMNI, /* # of message queue identifiers */
124 MSGMNB, /* max chars in a queue */
125 MSGTQL, /* max messages in system */
126 MSGSSZ, /* size of a message segment */
127 /* (must be small power of 2 greater than 4) */
128 MSGSEG /* number of message segments */
129};
130
131/*
132 * macros to convert between msqid_ds's and msqid's.
133 * (specific to this implementation)
134 */
135#define MSQID(ix,ds) ((ix) & 0xffff | (((ds).msg_perm.seq << 16) & 0xffff0000))
136#define MSQID_IX(id) ((id) & 0xffff)
137#define MSQID_SEQ(id) (((id) >> 16) & 0xffff)
138
139/*
140 * The rest of this file is specific to this particular implementation.
141 */
142
143struct msgmap {
144 short next; /* next segment in buffer */
145 /* -1 -> available */
146 /* 0..(MSGSEG-1) -> index of next segment */
147};
148
149#define MSG_LOCKED 01000 /* Is this msqid_ds locked? */
150
151static int nfree_msgmaps; /* # of free map entries */
152static short free_msgmaps; /* head of linked list of free map entries */
153static struct msg *free_msghdrs;/* list of free msg headers */
154static char *msgpool; /* MSGMAX byte long msg buffer pool */
155static struct msgmap *msgmaps; /* MSGSEG msgmap structures */
156static struct msg *msghdrs; /* MSGTQL msg headers */
157static struct msqid_kernel *msqids; /* MSGMNI msqid_kernel struct's */
158static struct mtx msq_mtx; /* global mutex for message queues. */
159
160static void
161msginit()
162{
163 register int i;
164
165 TUNABLE_INT_FETCH("kern.ipc.msgseg", &msginfo.msgseg);
166 TUNABLE_INT_FETCH("kern.ipc.msgssz", &msginfo.msgssz);
167 msginfo.msgmax = msginfo.msgseg * msginfo.msgssz;
168 TUNABLE_INT_FETCH("kern.ipc.msgmni", &msginfo.msgmni);
169 TUNABLE_INT_FETCH("kern.ipc.msgmnb", &msginfo.msgmnb);
170 TUNABLE_INT_FETCH("kern.ipc.msgtql", &msginfo.msgtql);
171
172 msgpool = malloc(msginfo.msgmax, M_MSG, M_WAITOK);
173 if (msgpool == NULL)
174 panic("msgpool is NULL");
175 msgmaps = malloc(sizeof(struct msgmap) * msginfo.msgseg, M_MSG, M_WAITOK);
176 if (msgmaps == NULL)
177 panic("msgmaps is NULL");
178 msghdrs = malloc(sizeof(struct msg) * msginfo.msgtql, M_MSG, M_WAITOK);
179 if (msghdrs == NULL)
180 panic("msghdrs is NULL");
181 msqids = malloc(sizeof(struct msqid_kernel) * msginfo.msgmni, M_MSG,
182 M_WAITOK);
183 if (msqids == NULL)
184 panic("msqids is NULL");
185
186 /*
187 * msginfo.msgssz should be a power of two for efficiency reasons.
188 * It is also pretty silly if msginfo.msgssz is less than 8
189 * or greater than about 256 so ...
190 */
191
192 i = 8;
193 while (i < 1024 && i != msginfo.msgssz)
194 i <<= 1;
195 if (i != msginfo.msgssz) {
196 DPRINTF(("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz,
197 msginfo.msgssz));
198 panic("msginfo.msgssz not a small power of 2");
199 }
200
201 if (msginfo.msgseg > 32767) {
202 DPRINTF(("msginfo.msgseg=%d\n", msginfo.msgseg));
203 panic("msginfo.msgseg > 32767");
204 }
205
206 if (msgmaps == NULL)
207 panic("msgmaps is NULL");
208
209 for (i = 0; i < msginfo.msgseg; i++) {
210 if (i > 0)
211 msgmaps[i-1].next = i;
212 msgmaps[i].next = -1; /* implies entry is available */
213 }
214 free_msgmaps = 0;
215 nfree_msgmaps = msginfo.msgseg;
216
217 if (msghdrs == NULL)
218 panic("msghdrs is NULL");
219
220 for (i = 0; i < msginfo.msgtql; i++) {
221 msghdrs[i].msg_type = 0;
222 if (i > 0)
223 msghdrs[i-1].msg_next = &msghdrs[i];
224 msghdrs[i].msg_next = NULL;
225#ifdef MAC
226 mac_sysvmsg_init(&msghdrs[i]);
227#endif
228 }
229 free_msghdrs = &msghdrs[0];
230
231 if (msqids == NULL)
232 panic("msqids is NULL");
233
234 for (i = 0; i < msginfo.msgmni; i++) {
235 msqids[i].u.msg_qbytes = 0; /* implies entry is available */
236 msqids[i].u.msg_perm.seq = 0; /* reset to a known value */
237 msqids[i].u.msg_perm.mode = 0;
238#ifdef MAC
239 mac_sysvmsq_init(&msqids[i]);
240#endif
241 }
242 mtx_init(&msq_mtx, "msq", NULL, MTX_DEF);
243}
244
245static int
246msgunload()
247{
248 struct msqid_kernel *msqkptr;
249 int msqid;
250#ifdef MAC
251 int i;
252#endif
253
254 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
255 /*
256 * Look for an unallocated and unlocked msqid_ds.
257 * msqid_ds's can be locked by msgsnd or msgrcv while
258 * they are copying the message in/out. We can't
259 * re-use the entry until they release it.
260 */
261 msqkptr = &msqids[msqid];
262 if (msqkptr->u.msg_qbytes != 0 ||
263 (msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0)
264 break;
265 }
266 if (msqid != msginfo.msgmni)
267 return (EBUSY);
268
269#ifdef MAC
270 for (i = 0; i < msginfo.msgtql; i++)
271 mac_sysvmsg_destroy(&msghdrs[i]);
272 for (msqid = 0; msqid < msginfo.msgmni; msqid++)
273 mac_sysvmsq_destroy(&msqids[msqid]);
274#endif
275 free(msgpool, M_MSG);
276 free(msgmaps, M_MSG);
277 free(msghdrs, M_MSG);
278 free(msqids, M_MSG);
279 mtx_destroy(&msq_mtx);
280 return (0);
281}
282
283
284static int
285sysvmsg_modload(struct module *module, int cmd, void *arg)
286{
287 int error = 0;
288
289 switch (cmd) {
290 case MOD_LOAD:
291 msginit();
292 break;
293 case MOD_UNLOAD:
294 error = msgunload();
295 break;
296 case MOD_SHUTDOWN:
297 break;
298 default:
299 error = EINVAL;
300 break;
301 }
302 return (error);
303}
304
305static moduledata_t sysvmsg_mod = {
306 "sysvmsg",
307 &sysvmsg_modload,
308 NULL
309};
310
311SYSCALL_MODULE_HELPER(msgsys);
312SYSCALL_MODULE_HELPER(msgctl);
313SYSCALL_MODULE_HELPER(msgget);
314SYSCALL_MODULE_HELPER(msgsnd);
315SYSCALL_MODULE_HELPER(msgrcv);
316
317DECLARE_MODULE(sysvmsg, sysvmsg_mod,
318 SI_SUB_SYSV_MSG, SI_ORDER_FIRST);
319MODULE_VERSION(sysvmsg, 1);
320
321/*
322 * Entry point for all MSG calls.
323 */
324int
325msgsys(td, uap)
326 struct thread *td;
327 /* XXX actually varargs. */
328 struct msgsys_args /* {
329 int which;
330 int a2;
331 int a3;
332 int a4;
333 int a5;
334 int a6;
335 } */ *uap;
336{
337 int error;
338
339 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
340 return (ENOSYS);
341 if (uap->which < 0 ||
342 uap->which >= sizeof(msgcalls)/sizeof(msgcalls[0]))
343 return (EINVAL);
344 error = (*msgcalls[uap->which])(td, &uap->a2);
345 return (error);
346}
347
348static void
349msg_freehdr(msghdr)
350 struct msg *msghdr;
351{
352 while (msghdr->msg_ts > 0) {
353 short next;
354 if (msghdr->msg_spot < 0 || msghdr->msg_spot >= msginfo.msgseg)
355 panic("msghdr->msg_spot out of range");
356 next = msgmaps[msghdr->msg_spot].next;
357 msgmaps[msghdr->msg_spot].next = free_msgmaps;
358 free_msgmaps = msghdr->msg_spot;
359 nfree_msgmaps++;
360 msghdr->msg_spot = next;
361 if (msghdr->msg_ts >= msginfo.msgssz)
362 msghdr->msg_ts -= msginfo.msgssz;
363 else
364 msghdr->msg_ts = 0;
365 }
366 if (msghdr->msg_spot != -1)
367 panic("msghdr->msg_spot != -1");
368 msghdr->msg_next = free_msghdrs;
369 free_msghdrs = msghdr;
370#ifdef MAC
371 mac_sysvmsg_cleanup(msghdr);
372#endif
373}
374
375#ifndef _SYS_SYSPROTO_H_
376struct msgctl_args {
377 int msqid;
378 int cmd;
379 struct msqid_ds *buf;
380};
381#endif
382int
383msgctl(td, uap)
384 struct thread *td;
385 register struct msgctl_args *uap;
386{
387 int msqid = uap->msqid;
388 int cmd = uap->cmd;
389 struct msqid_ds msqbuf;
390 int error;
391
392 DPRINTF(("call to msgctl(%d, %d, %p)\n", msqid, cmd, uap->buf));
393 if (cmd == IPC_SET &&
394 (error = copyin(uap->buf, &msqbuf, sizeof(msqbuf))) != 0)
395 return (error);
396 error = kern_msgctl(td, msqid, cmd, &msqbuf);
397 if (cmd == IPC_STAT && error == 0)
398 error = copyout(&msqbuf, uap->buf, sizeof(struct msqid_ds));
399 return (error);
400}
401
402int
403kern_msgctl(td, msqid, cmd, msqbuf)
404 struct thread *td;
405 int msqid;
406 int cmd;
407 struct msqid_ds *msqbuf;
408{
409 int rval, error, msqix;
410 register struct msqid_kernel *msqkptr;
411
412 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
413 return (ENOSYS);
414
415 msqix = IPCID_TO_IX(msqid);
416
417 if (msqix < 0 || msqix >= msginfo.msgmni) {
418 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
419 msginfo.msgmni));
420 return (EINVAL);
421 }
422
423 msqkptr = &msqids[msqix];
424
425 mtx_lock(&msq_mtx);
426 if (msqkptr->u.msg_qbytes == 0) {
427 DPRINTF(("no such msqid\n"));
428 error = EINVAL;
429 goto done2;
430 }
431 if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
432 DPRINTF(("wrong sequence number\n"));
433 error = EINVAL;
434 goto done2;
435 }
436#ifdef MAC
437 error = mac_sysvmsq_check_msqctl(td->td_ucred, msqkptr, cmd);
438 if (error != 0)
439 goto done2;
440#endif
441
442 error = 0;
443 rval = 0;
444
445 switch (cmd) {
446
447 case IPC_RMID:
448 {
449 struct msg *msghdr;
450 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M)))
451 goto done2;
452
453#ifdef MAC
454 /*
455 * Check that the thread has MAC access permissions to
456 * individual msghdrs. Note: We need to do this in a
457 * separate loop because the actual loop alters the
458 * msq/msghdr info as it progresses, and there is no going
459 * back if half the way through we discover that the
460 * thread cannot free a certain msghdr. The msq will get
461 * into an inconsistent state.
462 */
463 for (msghdr = msqkptr->u.msg_first; msghdr != NULL;
464 msghdr = msghdr->msg_next) {
465 error = mac_sysvmsq_check_msgrmid(td->td_ucred, msghdr);
466 if (error != 0)
467 goto done2;
468 }
469#endif
470
471 /* Free the message headers */
472 msghdr = msqkptr->u.msg_first;
473 while (msghdr != NULL) {
474 struct msg *msghdr_tmp;
475
476 /* Free the segments of each message */
477 msqkptr->u.msg_cbytes -= msghdr->msg_ts;
478 msqkptr->u.msg_qnum--;
479 msghdr_tmp = msghdr;
480 msghdr = msghdr->msg_next;
481 msg_freehdr(msghdr_tmp);
482 }
483
484 if (msqkptr->u.msg_cbytes != 0)
485 panic("msg_cbytes is screwed up");
486 if (msqkptr->u.msg_qnum != 0)
487 panic("msg_qnum is screwed up");
488
489 msqkptr->u.msg_qbytes = 0; /* Mark it as free */
490
491#ifdef MAC
492 mac_sysvmsq_cleanup(msqkptr);
493#endif
494
495 wakeup(msqkptr);
496 }
497
498 break;
499
500 case IPC_SET:
501 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M)))
502 goto done2;
503 if (msqbuf->msg_qbytes > msqkptr->u.msg_qbytes) {
504 error = priv_check(td, PRIV_IPC_MSGSIZE);
505 if (error)
506 goto done2;
507 }
508 if (msqbuf->msg_qbytes > msginfo.msgmnb) {
509 DPRINTF(("can't increase msg_qbytes beyond %d"
510 "(truncating)\n", msginfo.msgmnb));
511 msqbuf->msg_qbytes = msginfo.msgmnb; /* silently restrict qbytes to system limit */
512 }
513 if (msqbuf->msg_qbytes == 0) {
514 DPRINTF(("can't reduce msg_qbytes to 0\n"));
515 error = EINVAL; /* non-standard errno! */
516 goto done2;
517 }
518 msqkptr->u.msg_perm.uid = msqbuf->msg_perm.uid; /* change the owner */
519 msqkptr->u.msg_perm.gid = msqbuf->msg_perm.gid; /* change the owner */
520 msqkptr->u.msg_perm.mode = (msqkptr->u.msg_perm.mode & ~0777) |
521 (msqbuf->msg_perm.mode & 0777);
522 msqkptr->u.msg_qbytes = msqbuf->msg_qbytes;
523 msqkptr->u.msg_ctime = time_second;
524 break;
525
526 case IPC_STAT:
527 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) {
528 DPRINTF(("requester doesn't have read access\n"));
529 goto done2;
530 }
531 *msqbuf = msqkptr->u;
532 break;
533
534 default:
535 DPRINTF(("invalid command %d\n", cmd));
536 error = EINVAL;
537 goto done2;
538 }
539
540 if (error == 0)
541 td->td_retval[0] = rval;
542done2:
543 mtx_unlock(&msq_mtx);
544 return (error);
545}
546
547#ifndef _SYS_SYSPROTO_H_
548struct msgget_args {
549 key_t key;
550 int msgflg;
551};
552#endif
553int
554msgget(td, uap)
555 struct thread *td;
556 register struct msgget_args *uap;
557{
558 int msqid, error = 0;
559 int key = uap->key;
560 int msgflg = uap->msgflg;
561 struct ucred *cred = td->td_ucred;
562 register struct msqid_kernel *msqkptr = NULL;
563
564 DPRINTF(("msgget(0x%x, 0%o)\n", key, msgflg));
565
566 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
567 return (ENOSYS);
568
569 mtx_lock(&msq_mtx);
570 if (key != IPC_PRIVATE) {
571 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
572 msqkptr = &msqids[msqid];
573 if (msqkptr->u.msg_qbytes != 0 &&
574 msqkptr->u.msg_perm.key == key)
575 break;
576 }
577 if (msqid < msginfo.msgmni) {
578 DPRINTF(("found public key\n"));
579 if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) {
580 DPRINTF(("not exclusive\n"));
581 error = EEXIST;
582 goto done2;
583 }
584 if ((error = ipcperm(td, &msqkptr->u.msg_perm,
585 msgflg & 0700))) {
586 DPRINTF(("requester doesn't have 0%o access\n",
587 msgflg & 0700));
588 goto done2;
589 }
590#ifdef MAC
591 error = mac_sysvmsq_check_msqget(cred, msqkptr);
592 if (error != 0)
593 goto done2;
594#endif
595 goto found;
596 }
597 }
598
599 DPRINTF(("need to allocate the msqid_ds\n"));
600 if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) {
601 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
602 /*
603 * Look for an unallocated and unlocked msqid_ds.
604 * msqid_ds's can be locked by msgsnd or msgrcv while
605 * they are copying the message in/out. We can't
606 * re-use the entry until they release it.
607 */
608 msqkptr = &msqids[msqid];
609 if (msqkptr->u.msg_qbytes == 0 &&
610 (msqkptr->u.msg_perm.mode & MSG_LOCKED) == 0)
611 break;
612 }
613 if (msqid == msginfo.msgmni) {
614 DPRINTF(("no more msqid_ds's available\n"));
615 error = ENOSPC;
616 goto done2;
617 }
618 DPRINTF(("msqid %d is available\n", msqid));
619 msqkptr->u.msg_perm.key = key;
620 msqkptr->u.msg_perm.cuid = cred->cr_uid;
621 msqkptr->u.msg_perm.uid = cred->cr_uid;
622 msqkptr->u.msg_perm.cgid = cred->cr_gid;
623 msqkptr->u.msg_perm.gid = cred->cr_gid;
624 msqkptr->u.msg_perm.mode = (msgflg & 0777);
625 /* Make sure that the returned msqid is unique */
626 msqkptr->u.msg_perm.seq = (msqkptr->u.msg_perm.seq + 1) & 0x7fff;
627 msqkptr->u.msg_first = NULL;
628 msqkptr->u.msg_last = NULL;
629 msqkptr->u.msg_cbytes = 0;
630 msqkptr->u.msg_qnum = 0;
631 msqkptr->u.msg_qbytes = msginfo.msgmnb;
632 msqkptr->u.msg_lspid = 0;
633 msqkptr->u.msg_lrpid = 0;
634 msqkptr->u.msg_stime = 0;
635 msqkptr->u.msg_rtime = 0;
636 msqkptr->u.msg_ctime = time_second;
637#ifdef MAC
638 mac_sysvmsq_create(cred, msqkptr);
639#endif
640 } else {
641 DPRINTF(("didn't find it and wasn't asked to create it\n"));
642 error = ENOENT;
643 goto done2;
644 }
645
646found:
647 /* Construct the unique msqid */
648 td->td_retval[0] = IXSEQ_TO_IPCID(msqid, msqkptr->u.msg_perm);
649done2:
650 mtx_unlock(&msq_mtx);
651 return (error);
652}
653
654#ifndef _SYS_SYSPROTO_H_
655struct msgsnd_args {
656 int msqid;
657 const void *msgp;
658 size_t msgsz;
659 int msgflg;
660};
661#endif
662int
663kern_msgsnd(td, msqid, msgp, msgsz, msgflg, mtype)
664 struct thread *td;
665 int msqid;
666 const void *msgp; /* XXX msgp is actually mtext. */
667 size_t msgsz;
668 int msgflg;
669 long mtype;
670{
671 int msqix, segs_needed, error = 0;
672 register struct msqid_kernel *msqkptr;
673 register struct msg *msghdr;
674 short next;
675
676 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
677 return (ENOSYS);
678
679 mtx_lock(&msq_mtx);
680 msqix = IPCID_TO_IX(msqid);
681
682 if (msqix < 0 || msqix >= msginfo.msgmni) {
683 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
684 msginfo.msgmni));
685 error = EINVAL;
686 goto done2;
687 }
688
689 msqkptr = &msqids[msqix];
690 if (msqkptr->u.msg_qbytes == 0) {
691 DPRINTF(("no such message queue id\n"));
692 error = EINVAL;
693 goto done2;
694 }
695 if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
696 DPRINTF(("wrong sequence number\n"));
697 error = EINVAL;
698 goto done2;
699 }
700
701 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_W))) {
702 DPRINTF(("requester doesn't have write access\n"));
703 goto done2;
704 }
705
706#ifdef MAC
707 error = mac_sysvmsq_check_msqsnd(td->td_ucred, msqkptr);
708 if (error != 0)
709 goto done2;
710#endif
711
712 segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz;
713 DPRINTF(("msgsz=%zu, msgssz=%d, segs_needed=%d\n", msgsz,
714 msginfo.msgssz, segs_needed));
715 for (;;) {
716 int need_more_resources = 0;
717
718 /*
719 * check msgsz
720 * (inside this loop in case msg_qbytes changes while we sleep)
721 */
722
723 if (msgsz > msqkptr->u.msg_qbytes) {
724 DPRINTF(("msgsz > msqkptr->u.msg_qbytes\n"));
725 error = EINVAL;
726 goto done2;
727 }
728
729 if (msqkptr->u.msg_perm.mode & MSG_LOCKED) {
730 DPRINTF(("msqid is locked\n"));
731 need_more_resources = 1;
732 }
733 if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes) {
734 DPRINTF(("msgsz + msg_cbytes > msg_qbytes\n"));
735 need_more_resources = 1;
736 }
737 if (segs_needed > nfree_msgmaps) {
738 DPRINTF(("segs_needed > nfree_msgmaps\n"));
739 need_more_resources = 1;
740 }
741 if (free_msghdrs == NULL) {
742 DPRINTF(("no more msghdrs\n"));
743 need_more_resources = 1;
744 }
745
746 if (need_more_resources) {
747 int we_own_it;
748
749 if ((msgflg & IPC_NOWAIT) != 0) {
750 DPRINTF(("need more resources but caller "
751 "doesn't want to wait\n"));
752 error = EAGAIN;
753 goto done2;
754 }
755
756 if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0) {
757 DPRINTF(("we don't own the msqid_ds\n"));
758 we_own_it = 0;
759 } else {
760 /* Force later arrivals to wait for our
761 request */
762 DPRINTF(("we own the msqid_ds\n"));
763 msqkptr->u.msg_perm.mode |= MSG_LOCKED;
764 we_own_it = 1;
765 }
766 DPRINTF(("msgsnd: goodnight\n"));
767 error = msleep(msqkptr, &msq_mtx, (PZERO - 4) | PCATCH,
768 "msgsnd", hz);
769 DPRINTF(("msgsnd: good morning, error=%d\n", error));
770 if (we_own_it)
771 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
772 if (error == EWOULDBLOCK) {
773 DPRINTF(("msgsnd: timed out\n"));
774 continue;
775 }
776 if (error != 0) {
777 DPRINTF(("msgsnd: interrupted system call\n"));
778 error = EINTR;
779 goto done2;
780 }
781
782 /*
783 * Make sure that the msq queue still exists
784 */
785
786 if (msqkptr->u.msg_qbytes == 0) {
787 DPRINTF(("msqid deleted\n"));
788 error = EIDRM;
789 goto done2;
790 }
791
792 } else {
793 DPRINTF(("got all the resources that we need\n"));
794 break;
795 }
796 }
797
798 /*
799 * We have the resources that we need.
800 * Make sure!
801 */
802
803 if (msqkptr->u.msg_perm.mode & MSG_LOCKED)
804 panic("msg_perm.mode & MSG_LOCKED");
805 if (segs_needed > nfree_msgmaps)
806 panic("segs_needed > nfree_msgmaps");
807 if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes)
808 panic("msgsz + msg_cbytes > msg_qbytes");
809 if (free_msghdrs == NULL)
810 panic("no more msghdrs");
811
812 /*
813 * Re-lock the msqid_ds in case we page-fault when copying in the
814 * message
815 */
816
817 if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0)
818 panic("msqid_ds is already locked");
819 msqkptr->u.msg_perm.mode |= MSG_LOCKED;
820
821 /*
822 * Allocate a message header
823 */
824
825 msghdr = free_msghdrs;
826 free_msghdrs = msghdr->msg_next;
827 msghdr->msg_spot = -1;
828 msghdr->msg_ts = msgsz;
829 msghdr->msg_type = mtype;
830#ifdef MAC
831 /*
832 * XXXMAC: Should the mac_sysvmsq_check_msgmsq check follow here
833 * immediately? Or, should it be checked just before the msg is
834 * enqueued in the msgq (as it is done now)?
835 */
836 mac_sysvmsg_create(td->td_ucred, msqkptr, msghdr);
837#endif
838
839 /*
840 * Allocate space for the message
841 */
842
843 while (segs_needed > 0) {
844 if (nfree_msgmaps <= 0)
845 panic("not enough msgmaps");
846 if (free_msgmaps == -1)
847 panic("nil free_msgmaps");
848 next = free_msgmaps;
849 if (next <= -1)
850 panic("next too low #1");
851 if (next >= msginfo.msgseg)
852 panic("next out of range #1");
853 DPRINTF(("allocating segment %d to message\n", next));
854 free_msgmaps = msgmaps[next].next;
855 nfree_msgmaps--;
856 msgmaps[next].next = msghdr->msg_spot;
857 msghdr->msg_spot = next;
858 segs_needed--;
859 }
860
861 /*
862 * Validate the message type
863 */
864
865 if (msghdr->msg_type < 1) {
866 msg_freehdr(msghdr);
867 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
868 wakeup(msqkptr);
869 DPRINTF(("mtype (%ld) < 1\n", msghdr->msg_type));
870 error = EINVAL;
871 goto done2;
872 }
873
874 /*
875 * Copy in the message body
876 */
877
878 next = msghdr->msg_spot;
879 while (msgsz > 0) {
880 size_t tlen;
881 if (msgsz > msginfo.msgssz)
882 tlen = msginfo.msgssz;
883 else
884 tlen = msgsz;
885 if (next <= -1)
886 panic("next too low #2");
887 if (next >= msginfo.msgseg)
888 panic("next out of range #2");
889 mtx_unlock(&msq_mtx);
890 if ((error = copyin(msgp, &msgpool[next * msginfo.msgssz],
891 tlen)) != 0) {
892 mtx_lock(&msq_mtx);
893 DPRINTF(("error %d copying in message segment\n",
894 error));
895 msg_freehdr(msghdr);
896 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
897 wakeup(msqkptr);
898 goto done2;
899 }
900 mtx_lock(&msq_mtx);
901 msgsz -= tlen;
902 msgp = (const char *)msgp + tlen;
903 next = msgmaps[next].next;
904 }
905 if (next != -1)
906 panic("didn't use all the msg segments");
907
908 /*
909 * We've got the message. Unlock the msqid_ds.
910 */
911
912 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
913
914 /*
915 * Make sure that the msqid_ds is still allocated.
916 */
917
918 if (msqkptr->u.msg_qbytes == 0) {
919 msg_freehdr(msghdr);
920 wakeup(msqkptr);
921 error = EIDRM;
922 goto done2;
923 }
924
925#ifdef MAC
926 /*
927 * Note: Since the task/thread allocates the msghdr and usually
928 * primes it with its own MAC label, for a majority of policies, it
929 * won't be necessary to check whether the msghdr has access
930 * permissions to the msgq. The mac_sysvmsq_check_msqsnd check would
931 * suffice in that case. However, this hook may be required where
932 * individual policies derive a non-identical label for the msghdr
933 * from the current thread label and may want to check the msghdr
934 * enqueue permissions, along with read/write permissions to the
935 * msgq.
936 */
937 error = mac_sysvmsq_check_msgmsq(td->td_ucred, msghdr, msqkptr);
938 if (error != 0) {
939 msg_freehdr(msghdr);
940 wakeup(msqkptr);
941 goto done2;
942 }
943#endif
944
945 /*
946 * Put the message into the queue
947 */
948 if (msqkptr->u.msg_first == NULL) {
949 msqkptr->u.msg_first = msghdr;
950 msqkptr->u.msg_last = msghdr;
951 } else {
952 msqkptr->u.msg_last->msg_next = msghdr;
953 msqkptr->u.msg_last = msghdr;
954 }
955 msqkptr->u.msg_last->msg_next = NULL;
956
957 msqkptr->u.msg_cbytes += msghdr->msg_ts;
958 msqkptr->u.msg_qnum++;
959 msqkptr->u.msg_lspid = td->td_proc->p_pid;
960 msqkptr->u.msg_stime = time_second;
961
962 wakeup(msqkptr);
963 td->td_retval[0] = 0;
964done2:
965 mtx_unlock(&msq_mtx);
966 return (error);
967}
968
969int
970msgsnd(td, uap)
971 struct thread *td;
972 register struct msgsnd_args *uap;
973{
974 int error;
975 long mtype;
976
977 DPRINTF(("call to msgsnd(%d, %p, %zu, %d)\n", uap->msqid, uap->msgp,
978 uap->msgsz, uap->msgflg));
979
980 if ((error = copyin(uap->msgp, &mtype, sizeof(mtype))) != 0) {
981 DPRINTF(("error %d copying the message type\n", error));
982 return (error);
983 }
984 return (kern_msgsnd(td, uap->msqid,
985 (const char *)uap->msgp + sizeof(mtype),
986 uap->msgsz, uap->msgflg, mtype));
987}
988
989#ifndef _SYS_SYSPROTO_H_
990struct msgrcv_args {
991 int msqid;
992 void *msgp;
993 size_t msgsz;
994 long msgtyp;
995 int msgflg;
996};
997#endif
998int
999kern_msgrcv(td, msqid, msgp, msgsz, msgtyp, msgflg, mtype)
1000 struct thread *td;
1001 int msqid;
1002 void *msgp; /* XXX msgp is actually mtext. */
1003 size_t msgsz;
1004 long msgtyp;
1005 int msgflg;
1006 long *mtype;
1007{
1008 size_t len;
1009 register struct msqid_kernel *msqkptr;
1010 register struct msg *msghdr;
1011 int msqix, error = 0;
1012 short next;
1013
1014 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
1015 return (ENOSYS);
1016
1017 msqix = IPCID_TO_IX(msqid);
1018
1019 if (msqix < 0 || msqix >= msginfo.msgmni) {
1020 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
1021 msginfo.msgmni));
1022 return (EINVAL);
1023 }
1024
1025 msqkptr = &msqids[msqix];
1026 mtx_lock(&msq_mtx);
1027 if (msqkptr->u.msg_qbytes == 0) {
1028 DPRINTF(("no such message queue id\n"));
1029 error = EINVAL;
1030 goto done2;
1031 }
1032 if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
1033 DPRINTF(("wrong sequence number\n"));
1034 error = EINVAL;
1035 goto done2;
1036 }
1037
1038 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) {
1039 DPRINTF(("requester doesn't have read access\n"));
1040 goto done2;
1041 }
1042
1043#ifdef MAC
1044 error = mac_sysvmsq_check_msqrcv(td->td_ucred, msqkptr);
1045 if (error != 0)
1046 goto done2;
1047#endif
1048
1049 msghdr = NULL;
1050 while (msghdr == NULL) {
1051 if (msgtyp == 0) {
1052 msghdr = msqkptr->u.msg_first;
1053 if (msghdr != NULL) {
1054 if (msgsz < msghdr->msg_ts &&
1055 (msgflg & MSG_NOERROR) == 0) {
1056 DPRINTF(("first message on the queue "
1057 "is too big (want %zu, got %d)\n",
1058 msgsz, msghdr->msg_ts));
1059 error = E2BIG;
1060 goto done2;
1061 }
1062#ifdef MAC
1063 error = mac_sysvmsq_check_msgrcv(td->td_ucred,
1064 msghdr);
1065 if (error != 0)
1066 goto done2;
1067#endif
1068 if (msqkptr->u.msg_first == msqkptr->u.msg_last) {
1069 msqkptr->u.msg_first = NULL;
1070 msqkptr->u.msg_last = NULL;
1071 } else {
1072 msqkptr->u.msg_first = msghdr->msg_next;
1073 if (msqkptr->u.msg_first == NULL)
1074 panic("msg_first/last screwed up #1");
1075 }
1076 }
1077 } else {
1078 struct msg *previous;
1079 struct msg **prev;
1080
1081 previous = NULL;
1082 prev = &(msqkptr->u.msg_first);
1083 while ((msghdr = *prev) != NULL) {
1084 /*
1085 * Is this message's type an exact match or is
1086 * this message's type less than or equal to
1087 * the absolute value of a negative msgtyp?
1088 * Note that the second half of this test can
1089 * NEVER be true if msgtyp is positive since
1090 * msg_type is always positive!
1091 */
1092
1093 if (msgtyp == msghdr->msg_type ||
1094 msghdr->msg_type <= -msgtyp) {
1095 DPRINTF(("found message type %ld, "
1096 "requested %ld\n",
1097 msghdr->msg_type, msgtyp));
1098 if (msgsz < msghdr->msg_ts &&
1099 (msgflg & MSG_NOERROR) == 0) {
1100 DPRINTF(("requested message "
1101 "on the queue is too big "
1102 "(want %zu, got %hu)\n",
1103 msgsz, msghdr->msg_ts));
1104 error = E2BIG;
1105 goto done2;
1106 }
1107#ifdef MAC
1108 error = mac_sysvmsq_check_msgrcv(
1109 td->td_ucred, msghdr);
1110 if (error != 0)
1111 goto done2;
1112#endif
1113 *prev = msghdr->msg_next;
1114 if (msghdr == msqkptr->u.msg_last) {
1115 if (previous == NULL) {
1116 if (prev !=
1117 &msqkptr->u.msg_first)
1118 panic("msg_first/last screwed up #2");
1119 msqkptr->u.msg_first =
1120 NULL;
1121 msqkptr->u.msg_last =
1122 NULL;
1123 } else {
1124 if (prev ==
1125 &msqkptr->u.msg_first)
1126 panic("msg_first/last screwed up #3");
1127 msqkptr->u.msg_last =
1128 previous;
1129 }
1130 }
1131 break;
1132 }
1133 previous = msghdr;
1134 prev = &(msghdr->msg_next);
1135 }
1136 }
1137
1138 /*
1139 * We've either extracted the msghdr for the appropriate
1140 * message or there isn't one.
1141 * If there is one then bail out of this loop.
1142 */
1143
1144 if (msghdr != NULL)
1145 break;
1146
1147 /*
1148 * Hmph! No message found. Does the user want to wait?
1149 */
1150
1151 if ((msgflg & IPC_NOWAIT) != 0) {
1152 DPRINTF(("no appropriate message found (msgtyp=%ld)\n",
1153 msgtyp));
1154 /* The SVID says to return ENOMSG. */
1155 error = ENOMSG;
1156 goto done2;
1157 }
1158
1159 /*
1160 * Wait for something to happen
1161 */
1162
1163 DPRINTF(("msgrcv: goodnight\n"));
1164 error = msleep(msqkptr, &msq_mtx, (PZERO - 4) | PCATCH,
1165 "msgrcv", 0);
1166 DPRINTF(("msgrcv: good morning (error=%d)\n", error));
1167
1168 if (error != 0) {
1169 DPRINTF(("msgrcv: interrupted system call\n"));
1170 error = EINTR;
1171 goto done2;
1172 }
1173
1174 /*
1175 * Make sure that the msq queue still exists
1176 */
1177
1178 if (msqkptr->u.msg_qbytes == 0 ||
1179 msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
1180 DPRINTF(("msqid deleted\n"));
1181 error = EIDRM;
1182 goto done2;
1183 }
1184 }
1185
1186 /*
1187 * Return the message to the user.
1188 *
1189 * First, do the bookkeeping (before we risk being interrupted).
1190 */
1191
1192 msqkptr->u.msg_cbytes -= msghdr->msg_ts;
1193 msqkptr->u.msg_qnum--;
1194 msqkptr->u.msg_lrpid = td->td_proc->p_pid;
1195 msqkptr->u.msg_rtime = time_second;
1196
1197 /*
1198 * Make msgsz the actual amount that we'll be returning.
1199 * Note that this effectively truncates the message if it is too long
1200 * (since msgsz is never increased).
1201 */
1202
1203 DPRINTF(("found a message, msgsz=%zu, msg_ts=%hu\n", msgsz,
1204 msghdr->msg_ts));
1205 if (msgsz > msghdr->msg_ts)
1206 msgsz = msghdr->msg_ts;
1207 *mtype = msghdr->msg_type;
1208
1209 /*
1210 * Return the segments to the user
1211 */
1212
1213 next = msghdr->msg_spot;
1214 for (len = 0; len < msgsz; len += msginfo.msgssz) {
1215 size_t tlen;
1216
1217 if (msgsz - len > msginfo.msgssz)
1218 tlen = msginfo.msgssz;
1219 else
1220 tlen = msgsz - len;
1221 if (next <= -1)
1222 panic("next too low #3");
1223 if (next >= msginfo.msgseg)
1224 panic("next out of range #3");
1225 mtx_unlock(&msq_mtx);
1226 error = copyout(&msgpool[next * msginfo.msgssz], msgp, tlen);
1227 mtx_lock(&msq_mtx);
1228 if (error != 0) {
1229 DPRINTF(("error (%d) copying out message segment\n",
1230 error));
1231 msg_freehdr(msghdr);
1232 wakeup(msqkptr);
1233 goto done2;
1234 }
1235 msgp = (char *)msgp + tlen;
1236 next = msgmaps[next].next;
1237 }
1238
1239 /*
1240 * Done, return the actual number of bytes copied out.
1241 */
1242
1243 msg_freehdr(msghdr);
1244 wakeup(msqkptr);
1245 td->td_retval[0] = msgsz;
1246done2:
1247 mtx_unlock(&msq_mtx);
1248 return (error);
1249}
1250
1251int
1252msgrcv(td, uap)
1253 struct thread *td;
1254 register struct msgrcv_args *uap;
1255{
1256 int error;
1257 long mtype;
1258
1259 DPRINTF(("call to msgrcv(%d, %p, %zu, %ld, %d)\n", uap->msqid,
1260 uap->msgp, uap->msgsz, uap->msgtyp, uap->msgflg));
1261
1262 if ((error = kern_msgrcv(td, uap->msqid,
1263 (char *)uap->msgp + sizeof(mtype), uap->msgsz,
1264 uap->msgtyp, uap->msgflg, &mtype)) != 0)
1265 return (error);
1266 if ((error = copyout(&mtype, uap->msgp, sizeof(mtype))) != 0)
1267 DPRINTF(("error %d copying the message type\n", error));
1268 return (error);
1269}
1270
1271static int
1272sysctl_msqids(SYSCTL_HANDLER_ARGS)
1273{
1274
1275 return (SYSCTL_OUT(req, msqids,
1276 sizeof(struct msqid_kernel) * msginfo.msgmni));
1277}
1278
1279SYSCTL_INT(_kern_ipc, OID_AUTO, msgmax, CTLFLAG_RD, &msginfo.msgmax, 0,
1280 "Maximum message size");
1281SYSCTL_INT(_kern_ipc, OID_AUTO, msgmni, CTLFLAG_RDTUN, &msginfo.msgmni, 0,
1282 "Number of message queue identifiers");
1283SYSCTL_INT(_kern_ipc, OID_AUTO, msgmnb, CTLFLAG_RDTUN, &msginfo.msgmnb, 0,
1284 "Maximum number of bytes in a queue");
1285SYSCTL_INT(_kern_ipc, OID_AUTO, msgtql, CTLFLAG_RDTUN, &msginfo.msgtql, 0,
1286 "Maximum number of messages in the system");
1287SYSCTL_INT(_kern_ipc, OID_AUTO, msgssz, CTLFLAG_RDTUN, &msginfo.msgssz, 0,
1288 "Size of a message segment");
1289SYSCTL_INT(_kern_ipc, OID_AUTO, msgseg, CTLFLAG_RDTUN, &msginfo.msgseg, 0,
1290 "Number of message segments");
1291SYSCTL_PROC(_kern_ipc, OID_AUTO, msqids, CTLFLAG_RD,
1292 NULL, 0, sysctl_msqids, "", "Message queue IDs");
2 * Implementation of SVID messages
3 *
4 * Author: Daniel Boulet
5 *
6 * Copyright 1993 Daniel Boulet and RTMX Inc.
7 *
8 * This system call was implemented by Daniel Boulet under contract from RTMX.
9 *
10 * Redistribution and use in source forms, with and without modification,
11 * are permitted provided that this entire comment appears intact.
12 *
13 * Redistribution in binary form may occur without any restrictions.
14 * Obviously, it would be nice if you gave credit where credit is due
15 * but requiring it would be too onerous.
16 *
17 * This software is provided ``AS IS'' without any warranties of any kind.
18 */
19/*-
20 * Copyright (c) 2003-2005 McAfee, Inc.
21 * All rights reserved.
22 *
23 * This software was developed for the FreeBSD Project in part by McAfee
24 * Research, the Security Research Division of McAfee, Inc under DARPA/SPAWAR
25 * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research
26 * program.
27 *
28 * Redistribution and use in source and binary forms, with or without
29 * modification, are permitted provided that the following conditions
30 * are met:
31 * 1. Redistributions of source code must retain the above copyright
32 * notice, this list of conditions and the following disclaimer.
33 * 2. Redistributions in binary form must reproduce the above copyright
34 * notice, this list of conditions and the following disclaimer in the
35 * documentation and/or other materials provided with the distribution.
36 *
37 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
38 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
39 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
40 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
41 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
42 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
43 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
44 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
45 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
46 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
47 * SUCH DAMAGE.
48 */
49
50#include <sys/cdefs.h>
51__FBSDID("$FreeBSD: head/sys/kern/sysv_msg.c 193511 2009-06-05 14:55:22Z rwatson $");
52
53#include "opt_sysvipc.h"
54
55#include <sys/param.h>
56#include <sys/systm.h>
57#include <sys/sysproto.h>
58#include <sys/kernel.h>
59#include <sys/priv.h>
60#include <sys/proc.h>
61#include <sys/lock.h>
62#include <sys/mutex.h>
63#include <sys/module.h>
64#include <sys/msg.h>
65#include <sys/syscall.h>
66#include <sys/syscallsubr.h>
67#include <sys/sysent.h>
68#include <sys/sysctl.h>
69#include <sys/malloc.h>
70#include <sys/jail.h>
71
72#include <security/mac/mac_framework.h>
73
74static MALLOC_DEFINE(M_MSG, "msg", "SVID compatible message queues");
75
76static void msginit(void);
77static int msgunload(void);
78static int sysvmsg_modload(struct module *, int, void *);
79
80#ifdef MSG_DEBUG
81#define DPRINTF(a) printf a
82#else
83#define DPRINTF(a)
84#endif
85
86static void msg_freehdr(struct msg *msghdr);
87
88/* XXX casting to (sy_call_t *) is bogus, as usual. */
89static sy_call_t *msgcalls[] = {
90 (sy_call_t *)msgctl, (sy_call_t *)msgget,
91 (sy_call_t *)msgsnd, (sy_call_t *)msgrcv
92};
93
94#ifndef MSGSSZ
95#define MSGSSZ 8 /* Each segment must be 2^N long */
96#endif
97#ifndef MSGSEG
98#define MSGSEG 2048 /* must be less than 32767 */
99#endif
100#define MSGMAX (MSGSSZ*MSGSEG)
101#ifndef MSGMNB
102#define MSGMNB 2048 /* max # of bytes in a queue */
103#endif
104#ifndef MSGMNI
105#define MSGMNI 40
106#endif
107#ifndef MSGTQL
108#define MSGTQL 40
109#endif
110
111/*
112 * Based on the configuration parameters described in an SVR2 (yes, two)
113 * config(1m) man page.
114 *
115 * Each message is broken up and stored in segments that are msgssz bytes
116 * long. For efficiency reasons, this should be a power of two. Also,
117 * it doesn't make sense if it is less than 8 or greater than about 256.
118 * Consequently, msginit in kern/sysv_msg.c checks that msgssz is a power of
119 * two between 8 and 1024 inclusive (and panic's if it isn't).
120 */
121struct msginfo msginfo = {
122 MSGMAX, /* max chars in a message */
123 MSGMNI, /* # of message queue identifiers */
124 MSGMNB, /* max chars in a queue */
125 MSGTQL, /* max messages in system */
126 MSGSSZ, /* size of a message segment */
127 /* (must be small power of 2 greater than 4) */
128 MSGSEG /* number of message segments */
129};
130
131/*
132 * macros to convert between msqid_ds's and msqid's.
133 * (specific to this implementation)
134 */
135#define MSQID(ix,ds) ((ix) & 0xffff | (((ds).msg_perm.seq << 16) & 0xffff0000))
136#define MSQID_IX(id) ((id) & 0xffff)
137#define MSQID_SEQ(id) (((id) >> 16) & 0xffff)
138
139/*
140 * The rest of this file is specific to this particular implementation.
141 */
142
143struct msgmap {
144 short next; /* next segment in buffer */
145 /* -1 -> available */
146 /* 0..(MSGSEG-1) -> index of next segment */
147};
148
149#define MSG_LOCKED 01000 /* Is this msqid_ds locked? */
150
151static int nfree_msgmaps; /* # of free map entries */
152static short free_msgmaps; /* head of linked list of free map entries */
153static struct msg *free_msghdrs;/* list of free msg headers */
154static char *msgpool; /* MSGMAX byte long msg buffer pool */
155static struct msgmap *msgmaps; /* MSGSEG msgmap structures */
156static struct msg *msghdrs; /* MSGTQL msg headers */
157static struct msqid_kernel *msqids; /* MSGMNI msqid_kernel struct's */
158static struct mtx msq_mtx; /* global mutex for message queues. */
159
160static void
161msginit()
162{
163 register int i;
164
165 TUNABLE_INT_FETCH("kern.ipc.msgseg", &msginfo.msgseg);
166 TUNABLE_INT_FETCH("kern.ipc.msgssz", &msginfo.msgssz);
167 msginfo.msgmax = msginfo.msgseg * msginfo.msgssz;
168 TUNABLE_INT_FETCH("kern.ipc.msgmni", &msginfo.msgmni);
169 TUNABLE_INT_FETCH("kern.ipc.msgmnb", &msginfo.msgmnb);
170 TUNABLE_INT_FETCH("kern.ipc.msgtql", &msginfo.msgtql);
171
172 msgpool = malloc(msginfo.msgmax, M_MSG, M_WAITOK);
173 if (msgpool == NULL)
174 panic("msgpool is NULL");
175 msgmaps = malloc(sizeof(struct msgmap) * msginfo.msgseg, M_MSG, M_WAITOK);
176 if (msgmaps == NULL)
177 panic("msgmaps is NULL");
178 msghdrs = malloc(sizeof(struct msg) * msginfo.msgtql, M_MSG, M_WAITOK);
179 if (msghdrs == NULL)
180 panic("msghdrs is NULL");
181 msqids = malloc(sizeof(struct msqid_kernel) * msginfo.msgmni, M_MSG,
182 M_WAITOK);
183 if (msqids == NULL)
184 panic("msqids is NULL");
185
186 /*
187 * msginfo.msgssz should be a power of two for efficiency reasons.
188 * It is also pretty silly if msginfo.msgssz is less than 8
189 * or greater than about 256 so ...
190 */
191
192 i = 8;
193 while (i < 1024 && i != msginfo.msgssz)
194 i <<= 1;
195 if (i != msginfo.msgssz) {
196 DPRINTF(("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz,
197 msginfo.msgssz));
198 panic("msginfo.msgssz not a small power of 2");
199 }
200
201 if (msginfo.msgseg > 32767) {
202 DPRINTF(("msginfo.msgseg=%d\n", msginfo.msgseg));
203 panic("msginfo.msgseg > 32767");
204 }
205
206 if (msgmaps == NULL)
207 panic("msgmaps is NULL");
208
209 for (i = 0; i < msginfo.msgseg; i++) {
210 if (i > 0)
211 msgmaps[i-1].next = i;
212 msgmaps[i].next = -1; /* implies entry is available */
213 }
214 free_msgmaps = 0;
215 nfree_msgmaps = msginfo.msgseg;
216
217 if (msghdrs == NULL)
218 panic("msghdrs is NULL");
219
220 for (i = 0; i < msginfo.msgtql; i++) {
221 msghdrs[i].msg_type = 0;
222 if (i > 0)
223 msghdrs[i-1].msg_next = &msghdrs[i];
224 msghdrs[i].msg_next = NULL;
225#ifdef MAC
226 mac_sysvmsg_init(&msghdrs[i]);
227#endif
228 }
229 free_msghdrs = &msghdrs[0];
230
231 if (msqids == NULL)
232 panic("msqids is NULL");
233
234 for (i = 0; i < msginfo.msgmni; i++) {
235 msqids[i].u.msg_qbytes = 0; /* implies entry is available */
236 msqids[i].u.msg_perm.seq = 0; /* reset to a known value */
237 msqids[i].u.msg_perm.mode = 0;
238#ifdef MAC
239 mac_sysvmsq_init(&msqids[i]);
240#endif
241 }
242 mtx_init(&msq_mtx, "msq", NULL, MTX_DEF);
243}
244
245static int
246msgunload()
247{
248 struct msqid_kernel *msqkptr;
249 int msqid;
250#ifdef MAC
251 int i;
252#endif
253
254 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
255 /*
256 * Look for an unallocated and unlocked msqid_ds.
257 * msqid_ds's can be locked by msgsnd or msgrcv while
258 * they are copying the message in/out. We can't
259 * re-use the entry until they release it.
260 */
261 msqkptr = &msqids[msqid];
262 if (msqkptr->u.msg_qbytes != 0 ||
263 (msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0)
264 break;
265 }
266 if (msqid != msginfo.msgmni)
267 return (EBUSY);
268
269#ifdef MAC
270 for (i = 0; i < msginfo.msgtql; i++)
271 mac_sysvmsg_destroy(&msghdrs[i]);
272 for (msqid = 0; msqid < msginfo.msgmni; msqid++)
273 mac_sysvmsq_destroy(&msqids[msqid]);
274#endif
275 free(msgpool, M_MSG);
276 free(msgmaps, M_MSG);
277 free(msghdrs, M_MSG);
278 free(msqids, M_MSG);
279 mtx_destroy(&msq_mtx);
280 return (0);
281}
282
283
284static int
285sysvmsg_modload(struct module *module, int cmd, void *arg)
286{
287 int error = 0;
288
289 switch (cmd) {
290 case MOD_LOAD:
291 msginit();
292 break;
293 case MOD_UNLOAD:
294 error = msgunload();
295 break;
296 case MOD_SHUTDOWN:
297 break;
298 default:
299 error = EINVAL;
300 break;
301 }
302 return (error);
303}
304
305static moduledata_t sysvmsg_mod = {
306 "sysvmsg",
307 &sysvmsg_modload,
308 NULL
309};
310
311SYSCALL_MODULE_HELPER(msgsys);
312SYSCALL_MODULE_HELPER(msgctl);
313SYSCALL_MODULE_HELPER(msgget);
314SYSCALL_MODULE_HELPER(msgsnd);
315SYSCALL_MODULE_HELPER(msgrcv);
316
317DECLARE_MODULE(sysvmsg, sysvmsg_mod,
318 SI_SUB_SYSV_MSG, SI_ORDER_FIRST);
319MODULE_VERSION(sysvmsg, 1);
320
321/*
322 * Entry point for all MSG calls.
323 */
324int
325msgsys(td, uap)
326 struct thread *td;
327 /* XXX actually varargs. */
328 struct msgsys_args /* {
329 int which;
330 int a2;
331 int a3;
332 int a4;
333 int a5;
334 int a6;
335 } */ *uap;
336{
337 int error;
338
339 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
340 return (ENOSYS);
341 if (uap->which < 0 ||
342 uap->which >= sizeof(msgcalls)/sizeof(msgcalls[0]))
343 return (EINVAL);
344 error = (*msgcalls[uap->which])(td, &uap->a2);
345 return (error);
346}
347
348static void
349msg_freehdr(msghdr)
350 struct msg *msghdr;
351{
352 while (msghdr->msg_ts > 0) {
353 short next;
354 if (msghdr->msg_spot < 0 || msghdr->msg_spot >= msginfo.msgseg)
355 panic("msghdr->msg_spot out of range");
356 next = msgmaps[msghdr->msg_spot].next;
357 msgmaps[msghdr->msg_spot].next = free_msgmaps;
358 free_msgmaps = msghdr->msg_spot;
359 nfree_msgmaps++;
360 msghdr->msg_spot = next;
361 if (msghdr->msg_ts >= msginfo.msgssz)
362 msghdr->msg_ts -= msginfo.msgssz;
363 else
364 msghdr->msg_ts = 0;
365 }
366 if (msghdr->msg_spot != -1)
367 panic("msghdr->msg_spot != -1");
368 msghdr->msg_next = free_msghdrs;
369 free_msghdrs = msghdr;
370#ifdef MAC
371 mac_sysvmsg_cleanup(msghdr);
372#endif
373}
374
375#ifndef _SYS_SYSPROTO_H_
376struct msgctl_args {
377 int msqid;
378 int cmd;
379 struct msqid_ds *buf;
380};
381#endif
382int
383msgctl(td, uap)
384 struct thread *td;
385 register struct msgctl_args *uap;
386{
387 int msqid = uap->msqid;
388 int cmd = uap->cmd;
389 struct msqid_ds msqbuf;
390 int error;
391
392 DPRINTF(("call to msgctl(%d, %d, %p)\n", msqid, cmd, uap->buf));
393 if (cmd == IPC_SET &&
394 (error = copyin(uap->buf, &msqbuf, sizeof(msqbuf))) != 0)
395 return (error);
396 error = kern_msgctl(td, msqid, cmd, &msqbuf);
397 if (cmd == IPC_STAT && error == 0)
398 error = copyout(&msqbuf, uap->buf, sizeof(struct msqid_ds));
399 return (error);
400}
401
402int
403kern_msgctl(td, msqid, cmd, msqbuf)
404 struct thread *td;
405 int msqid;
406 int cmd;
407 struct msqid_ds *msqbuf;
408{
409 int rval, error, msqix;
410 register struct msqid_kernel *msqkptr;
411
412 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
413 return (ENOSYS);
414
415 msqix = IPCID_TO_IX(msqid);
416
417 if (msqix < 0 || msqix >= msginfo.msgmni) {
418 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
419 msginfo.msgmni));
420 return (EINVAL);
421 }
422
423 msqkptr = &msqids[msqix];
424
425 mtx_lock(&msq_mtx);
426 if (msqkptr->u.msg_qbytes == 0) {
427 DPRINTF(("no such msqid\n"));
428 error = EINVAL;
429 goto done2;
430 }
431 if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
432 DPRINTF(("wrong sequence number\n"));
433 error = EINVAL;
434 goto done2;
435 }
436#ifdef MAC
437 error = mac_sysvmsq_check_msqctl(td->td_ucred, msqkptr, cmd);
438 if (error != 0)
439 goto done2;
440#endif
441
442 error = 0;
443 rval = 0;
444
445 switch (cmd) {
446
447 case IPC_RMID:
448 {
449 struct msg *msghdr;
450 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M)))
451 goto done2;
452
453#ifdef MAC
454 /*
455 * Check that the thread has MAC access permissions to
456 * individual msghdrs. Note: We need to do this in a
457 * separate loop because the actual loop alters the
458 * msq/msghdr info as it progresses, and there is no going
459 * back if half the way through we discover that the
460 * thread cannot free a certain msghdr. The msq will get
461 * into an inconsistent state.
462 */
463 for (msghdr = msqkptr->u.msg_first; msghdr != NULL;
464 msghdr = msghdr->msg_next) {
465 error = mac_sysvmsq_check_msgrmid(td->td_ucred, msghdr);
466 if (error != 0)
467 goto done2;
468 }
469#endif
470
471 /* Free the message headers */
472 msghdr = msqkptr->u.msg_first;
473 while (msghdr != NULL) {
474 struct msg *msghdr_tmp;
475
476 /* Free the segments of each message */
477 msqkptr->u.msg_cbytes -= msghdr->msg_ts;
478 msqkptr->u.msg_qnum--;
479 msghdr_tmp = msghdr;
480 msghdr = msghdr->msg_next;
481 msg_freehdr(msghdr_tmp);
482 }
483
484 if (msqkptr->u.msg_cbytes != 0)
485 panic("msg_cbytes is screwed up");
486 if (msqkptr->u.msg_qnum != 0)
487 panic("msg_qnum is screwed up");
488
489 msqkptr->u.msg_qbytes = 0; /* Mark it as free */
490
491#ifdef MAC
492 mac_sysvmsq_cleanup(msqkptr);
493#endif
494
495 wakeup(msqkptr);
496 }
497
498 break;
499
500 case IPC_SET:
501 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M)))
502 goto done2;
503 if (msqbuf->msg_qbytes > msqkptr->u.msg_qbytes) {
504 error = priv_check(td, PRIV_IPC_MSGSIZE);
505 if (error)
506 goto done2;
507 }
508 if (msqbuf->msg_qbytes > msginfo.msgmnb) {
509 DPRINTF(("can't increase msg_qbytes beyond %d"
510 "(truncating)\n", msginfo.msgmnb));
511 msqbuf->msg_qbytes = msginfo.msgmnb; /* silently restrict qbytes to system limit */
512 }
513 if (msqbuf->msg_qbytes == 0) {
514 DPRINTF(("can't reduce msg_qbytes to 0\n"));
515 error = EINVAL; /* non-standard errno! */
516 goto done2;
517 }
518 msqkptr->u.msg_perm.uid = msqbuf->msg_perm.uid; /* change the owner */
519 msqkptr->u.msg_perm.gid = msqbuf->msg_perm.gid; /* change the owner */
520 msqkptr->u.msg_perm.mode = (msqkptr->u.msg_perm.mode & ~0777) |
521 (msqbuf->msg_perm.mode & 0777);
522 msqkptr->u.msg_qbytes = msqbuf->msg_qbytes;
523 msqkptr->u.msg_ctime = time_second;
524 break;
525
526 case IPC_STAT:
527 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) {
528 DPRINTF(("requester doesn't have read access\n"));
529 goto done2;
530 }
531 *msqbuf = msqkptr->u;
532 break;
533
534 default:
535 DPRINTF(("invalid command %d\n", cmd));
536 error = EINVAL;
537 goto done2;
538 }
539
540 if (error == 0)
541 td->td_retval[0] = rval;
542done2:
543 mtx_unlock(&msq_mtx);
544 return (error);
545}
546
547#ifndef _SYS_SYSPROTO_H_
548struct msgget_args {
549 key_t key;
550 int msgflg;
551};
552#endif
553int
554msgget(td, uap)
555 struct thread *td;
556 register struct msgget_args *uap;
557{
558 int msqid, error = 0;
559 int key = uap->key;
560 int msgflg = uap->msgflg;
561 struct ucred *cred = td->td_ucred;
562 register struct msqid_kernel *msqkptr = NULL;
563
564 DPRINTF(("msgget(0x%x, 0%o)\n", key, msgflg));
565
566 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
567 return (ENOSYS);
568
569 mtx_lock(&msq_mtx);
570 if (key != IPC_PRIVATE) {
571 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
572 msqkptr = &msqids[msqid];
573 if (msqkptr->u.msg_qbytes != 0 &&
574 msqkptr->u.msg_perm.key == key)
575 break;
576 }
577 if (msqid < msginfo.msgmni) {
578 DPRINTF(("found public key\n"));
579 if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) {
580 DPRINTF(("not exclusive\n"));
581 error = EEXIST;
582 goto done2;
583 }
584 if ((error = ipcperm(td, &msqkptr->u.msg_perm,
585 msgflg & 0700))) {
586 DPRINTF(("requester doesn't have 0%o access\n",
587 msgflg & 0700));
588 goto done2;
589 }
590#ifdef MAC
591 error = mac_sysvmsq_check_msqget(cred, msqkptr);
592 if (error != 0)
593 goto done2;
594#endif
595 goto found;
596 }
597 }
598
599 DPRINTF(("need to allocate the msqid_ds\n"));
600 if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) {
601 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
602 /*
603 * Look for an unallocated and unlocked msqid_ds.
604 * msqid_ds's can be locked by msgsnd or msgrcv while
605 * they are copying the message in/out. We can't
606 * re-use the entry until they release it.
607 */
608 msqkptr = &msqids[msqid];
609 if (msqkptr->u.msg_qbytes == 0 &&
610 (msqkptr->u.msg_perm.mode & MSG_LOCKED) == 0)
611 break;
612 }
613 if (msqid == msginfo.msgmni) {
614 DPRINTF(("no more msqid_ds's available\n"));
615 error = ENOSPC;
616 goto done2;
617 }
618 DPRINTF(("msqid %d is available\n", msqid));
619 msqkptr->u.msg_perm.key = key;
620 msqkptr->u.msg_perm.cuid = cred->cr_uid;
621 msqkptr->u.msg_perm.uid = cred->cr_uid;
622 msqkptr->u.msg_perm.cgid = cred->cr_gid;
623 msqkptr->u.msg_perm.gid = cred->cr_gid;
624 msqkptr->u.msg_perm.mode = (msgflg & 0777);
625 /* Make sure that the returned msqid is unique */
626 msqkptr->u.msg_perm.seq = (msqkptr->u.msg_perm.seq + 1) & 0x7fff;
627 msqkptr->u.msg_first = NULL;
628 msqkptr->u.msg_last = NULL;
629 msqkptr->u.msg_cbytes = 0;
630 msqkptr->u.msg_qnum = 0;
631 msqkptr->u.msg_qbytes = msginfo.msgmnb;
632 msqkptr->u.msg_lspid = 0;
633 msqkptr->u.msg_lrpid = 0;
634 msqkptr->u.msg_stime = 0;
635 msqkptr->u.msg_rtime = 0;
636 msqkptr->u.msg_ctime = time_second;
637#ifdef MAC
638 mac_sysvmsq_create(cred, msqkptr);
639#endif
640 } else {
641 DPRINTF(("didn't find it and wasn't asked to create it\n"));
642 error = ENOENT;
643 goto done2;
644 }
645
646found:
647 /* Construct the unique msqid */
648 td->td_retval[0] = IXSEQ_TO_IPCID(msqid, msqkptr->u.msg_perm);
649done2:
650 mtx_unlock(&msq_mtx);
651 return (error);
652}
653
654#ifndef _SYS_SYSPROTO_H_
655struct msgsnd_args {
656 int msqid;
657 const void *msgp;
658 size_t msgsz;
659 int msgflg;
660};
661#endif
662int
663kern_msgsnd(td, msqid, msgp, msgsz, msgflg, mtype)
664 struct thread *td;
665 int msqid;
666 const void *msgp; /* XXX msgp is actually mtext. */
667 size_t msgsz;
668 int msgflg;
669 long mtype;
670{
671 int msqix, segs_needed, error = 0;
672 register struct msqid_kernel *msqkptr;
673 register struct msg *msghdr;
674 short next;
675
676 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
677 return (ENOSYS);
678
679 mtx_lock(&msq_mtx);
680 msqix = IPCID_TO_IX(msqid);
681
682 if (msqix < 0 || msqix >= msginfo.msgmni) {
683 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
684 msginfo.msgmni));
685 error = EINVAL;
686 goto done2;
687 }
688
689 msqkptr = &msqids[msqix];
690 if (msqkptr->u.msg_qbytes == 0) {
691 DPRINTF(("no such message queue id\n"));
692 error = EINVAL;
693 goto done2;
694 }
695 if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
696 DPRINTF(("wrong sequence number\n"));
697 error = EINVAL;
698 goto done2;
699 }
700
701 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_W))) {
702 DPRINTF(("requester doesn't have write access\n"));
703 goto done2;
704 }
705
706#ifdef MAC
707 error = mac_sysvmsq_check_msqsnd(td->td_ucred, msqkptr);
708 if (error != 0)
709 goto done2;
710#endif
711
712 segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz;
713 DPRINTF(("msgsz=%zu, msgssz=%d, segs_needed=%d\n", msgsz,
714 msginfo.msgssz, segs_needed));
715 for (;;) {
716 int need_more_resources = 0;
717
718 /*
719 * check msgsz
720 * (inside this loop in case msg_qbytes changes while we sleep)
721 */
722
723 if (msgsz > msqkptr->u.msg_qbytes) {
724 DPRINTF(("msgsz > msqkptr->u.msg_qbytes\n"));
725 error = EINVAL;
726 goto done2;
727 }
728
729 if (msqkptr->u.msg_perm.mode & MSG_LOCKED) {
730 DPRINTF(("msqid is locked\n"));
731 need_more_resources = 1;
732 }
733 if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes) {
734 DPRINTF(("msgsz + msg_cbytes > msg_qbytes\n"));
735 need_more_resources = 1;
736 }
737 if (segs_needed > nfree_msgmaps) {
738 DPRINTF(("segs_needed > nfree_msgmaps\n"));
739 need_more_resources = 1;
740 }
741 if (free_msghdrs == NULL) {
742 DPRINTF(("no more msghdrs\n"));
743 need_more_resources = 1;
744 }
745
746 if (need_more_resources) {
747 int we_own_it;
748
749 if ((msgflg & IPC_NOWAIT) != 0) {
750 DPRINTF(("need more resources but caller "
751 "doesn't want to wait\n"));
752 error = EAGAIN;
753 goto done2;
754 }
755
756 if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0) {
757 DPRINTF(("we don't own the msqid_ds\n"));
758 we_own_it = 0;
759 } else {
760 /* Force later arrivals to wait for our
761 request */
762 DPRINTF(("we own the msqid_ds\n"));
763 msqkptr->u.msg_perm.mode |= MSG_LOCKED;
764 we_own_it = 1;
765 }
766 DPRINTF(("msgsnd: goodnight\n"));
767 error = msleep(msqkptr, &msq_mtx, (PZERO - 4) | PCATCH,
768 "msgsnd", hz);
769 DPRINTF(("msgsnd: good morning, error=%d\n", error));
770 if (we_own_it)
771 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
772 if (error == EWOULDBLOCK) {
773 DPRINTF(("msgsnd: timed out\n"));
774 continue;
775 }
776 if (error != 0) {
777 DPRINTF(("msgsnd: interrupted system call\n"));
778 error = EINTR;
779 goto done2;
780 }
781
782 /*
783 * Make sure that the msq queue still exists
784 */
785
786 if (msqkptr->u.msg_qbytes == 0) {
787 DPRINTF(("msqid deleted\n"));
788 error = EIDRM;
789 goto done2;
790 }
791
792 } else {
793 DPRINTF(("got all the resources that we need\n"));
794 break;
795 }
796 }
797
798 /*
799 * We have the resources that we need.
800 * Make sure!
801 */
802
803 if (msqkptr->u.msg_perm.mode & MSG_LOCKED)
804 panic("msg_perm.mode & MSG_LOCKED");
805 if (segs_needed > nfree_msgmaps)
806 panic("segs_needed > nfree_msgmaps");
807 if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes)
808 panic("msgsz + msg_cbytes > msg_qbytes");
809 if (free_msghdrs == NULL)
810 panic("no more msghdrs");
811
812 /*
813 * Re-lock the msqid_ds in case we page-fault when copying in the
814 * message
815 */
816
817 if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0)
818 panic("msqid_ds is already locked");
819 msqkptr->u.msg_perm.mode |= MSG_LOCKED;
820
821 /*
822 * Allocate a message header
823 */
824
825 msghdr = free_msghdrs;
826 free_msghdrs = msghdr->msg_next;
827 msghdr->msg_spot = -1;
828 msghdr->msg_ts = msgsz;
829 msghdr->msg_type = mtype;
830#ifdef MAC
831 /*
832 * XXXMAC: Should the mac_sysvmsq_check_msgmsq check follow here
833 * immediately? Or, should it be checked just before the msg is
834 * enqueued in the msgq (as it is done now)?
835 */
836 mac_sysvmsg_create(td->td_ucred, msqkptr, msghdr);
837#endif
838
839 /*
840 * Allocate space for the message
841 */
842
843 while (segs_needed > 0) {
844 if (nfree_msgmaps <= 0)
845 panic("not enough msgmaps");
846 if (free_msgmaps == -1)
847 panic("nil free_msgmaps");
848 next = free_msgmaps;
849 if (next <= -1)
850 panic("next too low #1");
851 if (next >= msginfo.msgseg)
852 panic("next out of range #1");
853 DPRINTF(("allocating segment %d to message\n", next));
854 free_msgmaps = msgmaps[next].next;
855 nfree_msgmaps--;
856 msgmaps[next].next = msghdr->msg_spot;
857 msghdr->msg_spot = next;
858 segs_needed--;
859 }
860
861 /*
862 * Validate the message type
863 */
864
865 if (msghdr->msg_type < 1) {
866 msg_freehdr(msghdr);
867 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
868 wakeup(msqkptr);
869 DPRINTF(("mtype (%ld) < 1\n", msghdr->msg_type));
870 error = EINVAL;
871 goto done2;
872 }
873
874 /*
875 * Copy in the message body
876 */
877
878 next = msghdr->msg_spot;
879 while (msgsz > 0) {
880 size_t tlen;
881 if (msgsz > msginfo.msgssz)
882 tlen = msginfo.msgssz;
883 else
884 tlen = msgsz;
885 if (next <= -1)
886 panic("next too low #2");
887 if (next >= msginfo.msgseg)
888 panic("next out of range #2");
889 mtx_unlock(&msq_mtx);
890 if ((error = copyin(msgp, &msgpool[next * msginfo.msgssz],
891 tlen)) != 0) {
892 mtx_lock(&msq_mtx);
893 DPRINTF(("error %d copying in message segment\n",
894 error));
895 msg_freehdr(msghdr);
896 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
897 wakeup(msqkptr);
898 goto done2;
899 }
900 mtx_lock(&msq_mtx);
901 msgsz -= tlen;
902 msgp = (const char *)msgp + tlen;
903 next = msgmaps[next].next;
904 }
905 if (next != -1)
906 panic("didn't use all the msg segments");
907
908 /*
909 * We've got the message. Unlock the msqid_ds.
910 */
911
912 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
913
914 /*
915 * Make sure that the msqid_ds is still allocated.
916 */
917
918 if (msqkptr->u.msg_qbytes == 0) {
919 msg_freehdr(msghdr);
920 wakeup(msqkptr);
921 error = EIDRM;
922 goto done2;
923 }
924
925#ifdef MAC
926 /*
927 * Note: Since the task/thread allocates the msghdr and usually
928 * primes it with its own MAC label, for a majority of policies, it
929 * won't be necessary to check whether the msghdr has access
930 * permissions to the msgq. The mac_sysvmsq_check_msqsnd check would
931 * suffice in that case. However, this hook may be required where
932 * individual policies derive a non-identical label for the msghdr
933 * from the current thread label and may want to check the msghdr
934 * enqueue permissions, along with read/write permissions to the
935 * msgq.
936 */
937 error = mac_sysvmsq_check_msgmsq(td->td_ucred, msghdr, msqkptr);
938 if (error != 0) {
939 msg_freehdr(msghdr);
940 wakeup(msqkptr);
941 goto done2;
942 }
943#endif
944
945 /*
946 * Put the message into the queue
947 */
948 if (msqkptr->u.msg_first == NULL) {
949 msqkptr->u.msg_first = msghdr;
950 msqkptr->u.msg_last = msghdr;
951 } else {
952 msqkptr->u.msg_last->msg_next = msghdr;
953 msqkptr->u.msg_last = msghdr;
954 }
955 msqkptr->u.msg_last->msg_next = NULL;
956
957 msqkptr->u.msg_cbytes += msghdr->msg_ts;
958 msqkptr->u.msg_qnum++;
959 msqkptr->u.msg_lspid = td->td_proc->p_pid;
960 msqkptr->u.msg_stime = time_second;
961
962 wakeup(msqkptr);
963 td->td_retval[0] = 0;
964done2:
965 mtx_unlock(&msq_mtx);
966 return (error);
967}
968
969int
970msgsnd(td, uap)
971 struct thread *td;
972 register struct msgsnd_args *uap;
973{
974 int error;
975 long mtype;
976
977 DPRINTF(("call to msgsnd(%d, %p, %zu, %d)\n", uap->msqid, uap->msgp,
978 uap->msgsz, uap->msgflg));
979
980 if ((error = copyin(uap->msgp, &mtype, sizeof(mtype))) != 0) {
981 DPRINTF(("error %d copying the message type\n", error));
982 return (error);
983 }
984 return (kern_msgsnd(td, uap->msqid,
985 (const char *)uap->msgp + sizeof(mtype),
986 uap->msgsz, uap->msgflg, mtype));
987}
988
989#ifndef _SYS_SYSPROTO_H_
990struct msgrcv_args {
991 int msqid;
992 void *msgp;
993 size_t msgsz;
994 long msgtyp;
995 int msgflg;
996};
997#endif
998int
999kern_msgrcv(td, msqid, msgp, msgsz, msgtyp, msgflg, mtype)
1000 struct thread *td;
1001 int msqid;
1002 void *msgp; /* XXX msgp is actually mtext. */
1003 size_t msgsz;
1004 long msgtyp;
1005 int msgflg;
1006 long *mtype;
1007{
1008 size_t len;
1009 register struct msqid_kernel *msqkptr;
1010 register struct msg *msghdr;
1011 int msqix, error = 0;
1012 short next;
1013
1014 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
1015 return (ENOSYS);
1016
1017 msqix = IPCID_TO_IX(msqid);
1018
1019 if (msqix < 0 || msqix >= msginfo.msgmni) {
1020 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
1021 msginfo.msgmni));
1022 return (EINVAL);
1023 }
1024
1025 msqkptr = &msqids[msqix];
1026 mtx_lock(&msq_mtx);
1027 if (msqkptr->u.msg_qbytes == 0) {
1028 DPRINTF(("no such message queue id\n"));
1029 error = EINVAL;
1030 goto done2;
1031 }
1032 if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
1033 DPRINTF(("wrong sequence number\n"));
1034 error = EINVAL;
1035 goto done2;
1036 }
1037
1038 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) {
1039 DPRINTF(("requester doesn't have read access\n"));
1040 goto done2;
1041 }
1042
1043#ifdef MAC
1044 error = mac_sysvmsq_check_msqrcv(td->td_ucred, msqkptr);
1045 if (error != 0)
1046 goto done2;
1047#endif
1048
1049 msghdr = NULL;
1050 while (msghdr == NULL) {
1051 if (msgtyp == 0) {
1052 msghdr = msqkptr->u.msg_first;
1053 if (msghdr != NULL) {
1054 if (msgsz < msghdr->msg_ts &&
1055 (msgflg & MSG_NOERROR) == 0) {
1056 DPRINTF(("first message on the queue "
1057 "is too big (want %zu, got %d)\n",
1058 msgsz, msghdr->msg_ts));
1059 error = E2BIG;
1060 goto done2;
1061 }
1062#ifdef MAC
1063 error = mac_sysvmsq_check_msgrcv(td->td_ucred,
1064 msghdr);
1065 if (error != 0)
1066 goto done2;
1067#endif
1068 if (msqkptr->u.msg_first == msqkptr->u.msg_last) {
1069 msqkptr->u.msg_first = NULL;
1070 msqkptr->u.msg_last = NULL;
1071 } else {
1072 msqkptr->u.msg_first = msghdr->msg_next;
1073 if (msqkptr->u.msg_first == NULL)
1074 panic("msg_first/last screwed up #1");
1075 }
1076 }
1077 } else {
1078 struct msg *previous;
1079 struct msg **prev;
1080
1081 previous = NULL;
1082 prev = &(msqkptr->u.msg_first);
1083 while ((msghdr = *prev) != NULL) {
1084 /*
1085 * Is this message's type an exact match or is
1086 * this message's type less than or equal to
1087 * the absolute value of a negative msgtyp?
1088 * Note that the second half of this test can
1089 * NEVER be true if msgtyp is positive since
1090 * msg_type is always positive!
1091 */
1092
1093 if (msgtyp == msghdr->msg_type ||
1094 msghdr->msg_type <= -msgtyp) {
1095 DPRINTF(("found message type %ld, "
1096 "requested %ld\n",
1097 msghdr->msg_type, msgtyp));
1098 if (msgsz < msghdr->msg_ts &&
1099 (msgflg & MSG_NOERROR) == 0) {
1100 DPRINTF(("requested message "
1101 "on the queue is too big "
1102 "(want %zu, got %hu)\n",
1103 msgsz, msghdr->msg_ts));
1104 error = E2BIG;
1105 goto done2;
1106 }
1107#ifdef MAC
1108 error = mac_sysvmsq_check_msgrcv(
1109 td->td_ucred, msghdr);
1110 if (error != 0)
1111 goto done2;
1112#endif
1113 *prev = msghdr->msg_next;
1114 if (msghdr == msqkptr->u.msg_last) {
1115 if (previous == NULL) {
1116 if (prev !=
1117 &msqkptr->u.msg_first)
1118 panic("msg_first/last screwed up #2");
1119 msqkptr->u.msg_first =
1120 NULL;
1121 msqkptr->u.msg_last =
1122 NULL;
1123 } else {
1124 if (prev ==
1125 &msqkptr->u.msg_first)
1126 panic("msg_first/last screwed up #3");
1127 msqkptr->u.msg_last =
1128 previous;
1129 }
1130 }
1131 break;
1132 }
1133 previous = msghdr;
1134 prev = &(msghdr->msg_next);
1135 }
1136 }
1137
1138 /*
1139 * We've either extracted the msghdr for the appropriate
1140 * message or there isn't one.
1141 * If there is one then bail out of this loop.
1142 */
1143
1144 if (msghdr != NULL)
1145 break;
1146
1147 /*
1148 * Hmph! No message found. Does the user want to wait?
1149 */
1150
1151 if ((msgflg & IPC_NOWAIT) != 0) {
1152 DPRINTF(("no appropriate message found (msgtyp=%ld)\n",
1153 msgtyp));
1154 /* The SVID says to return ENOMSG. */
1155 error = ENOMSG;
1156 goto done2;
1157 }
1158
1159 /*
1160 * Wait for something to happen
1161 */
1162
1163 DPRINTF(("msgrcv: goodnight\n"));
1164 error = msleep(msqkptr, &msq_mtx, (PZERO - 4) | PCATCH,
1165 "msgrcv", 0);
1166 DPRINTF(("msgrcv: good morning (error=%d)\n", error));
1167
1168 if (error != 0) {
1169 DPRINTF(("msgrcv: interrupted system call\n"));
1170 error = EINTR;
1171 goto done2;
1172 }
1173
1174 /*
1175 * Make sure that the msq queue still exists
1176 */
1177
1178 if (msqkptr->u.msg_qbytes == 0 ||
1179 msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
1180 DPRINTF(("msqid deleted\n"));
1181 error = EIDRM;
1182 goto done2;
1183 }
1184 }
1185
1186 /*
1187 * Return the message to the user.
1188 *
1189 * First, do the bookkeeping (before we risk being interrupted).
1190 */
1191
1192 msqkptr->u.msg_cbytes -= msghdr->msg_ts;
1193 msqkptr->u.msg_qnum--;
1194 msqkptr->u.msg_lrpid = td->td_proc->p_pid;
1195 msqkptr->u.msg_rtime = time_second;
1196
1197 /*
1198 * Make msgsz the actual amount that we'll be returning.
1199 * Note that this effectively truncates the message if it is too long
1200 * (since msgsz is never increased).
1201 */
1202
1203 DPRINTF(("found a message, msgsz=%zu, msg_ts=%hu\n", msgsz,
1204 msghdr->msg_ts));
1205 if (msgsz > msghdr->msg_ts)
1206 msgsz = msghdr->msg_ts;
1207 *mtype = msghdr->msg_type;
1208
1209 /*
1210 * Return the segments to the user
1211 */
1212
1213 next = msghdr->msg_spot;
1214 for (len = 0; len < msgsz; len += msginfo.msgssz) {
1215 size_t tlen;
1216
1217 if (msgsz - len > msginfo.msgssz)
1218 tlen = msginfo.msgssz;
1219 else
1220 tlen = msgsz - len;
1221 if (next <= -1)
1222 panic("next too low #3");
1223 if (next >= msginfo.msgseg)
1224 panic("next out of range #3");
1225 mtx_unlock(&msq_mtx);
1226 error = copyout(&msgpool[next * msginfo.msgssz], msgp, tlen);
1227 mtx_lock(&msq_mtx);
1228 if (error != 0) {
1229 DPRINTF(("error (%d) copying out message segment\n",
1230 error));
1231 msg_freehdr(msghdr);
1232 wakeup(msqkptr);
1233 goto done2;
1234 }
1235 msgp = (char *)msgp + tlen;
1236 next = msgmaps[next].next;
1237 }
1238
1239 /*
1240 * Done, return the actual number of bytes copied out.
1241 */
1242
1243 msg_freehdr(msghdr);
1244 wakeup(msqkptr);
1245 td->td_retval[0] = msgsz;
1246done2:
1247 mtx_unlock(&msq_mtx);
1248 return (error);
1249}
1250
1251int
1252msgrcv(td, uap)
1253 struct thread *td;
1254 register struct msgrcv_args *uap;
1255{
1256 int error;
1257 long mtype;
1258
1259 DPRINTF(("call to msgrcv(%d, %p, %zu, %ld, %d)\n", uap->msqid,
1260 uap->msgp, uap->msgsz, uap->msgtyp, uap->msgflg));
1261
1262 if ((error = kern_msgrcv(td, uap->msqid,
1263 (char *)uap->msgp + sizeof(mtype), uap->msgsz,
1264 uap->msgtyp, uap->msgflg, &mtype)) != 0)
1265 return (error);
1266 if ((error = copyout(&mtype, uap->msgp, sizeof(mtype))) != 0)
1267 DPRINTF(("error %d copying the message type\n", error));
1268 return (error);
1269}
1270
1271static int
1272sysctl_msqids(SYSCTL_HANDLER_ARGS)
1273{
1274
1275 return (SYSCTL_OUT(req, msqids,
1276 sizeof(struct msqid_kernel) * msginfo.msgmni));
1277}
1278
1279SYSCTL_INT(_kern_ipc, OID_AUTO, msgmax, CTLFLAG_RD, &msginfo.msgmax, 0,
1280 "Maximum message size");
1281SYSCTL_INT(_kern_ipc, OID_AUTO, msgmni, CTLFLAG_RDTUN, &msginfo.msgmni, 0,
1282 "Number of message queue identifiers");
1283SYSCTL_INT(_kern_ipc, OID_AUTO, msgmnb, CTLFLAG_RDTUN, &msginfo.msgmnb, 0,
1284 "Maximum number of bytes in a queue");
1285SYSCTL_INT(_kern_ipc, OID_AUTO, msgtql, CTLFLAG_RDTUN, &msginfo.msgtql, 0,
1286 "Maximum number of messages in the system");
1287SYSCTL_INT(_kern_ipc, OID_AUTO, msgssz, CTLFLAG_RDTUN, &msginfo.msgssz, 0,
1288 "Size of a message segment");
1289SYSCTL_INT(_kern_ipc, OID_AUTO, msgseg, CTLFLAG_RDTUN, &msginfo.msgseg, 0,
1290 "Number of message segments");
1291SYSCTL_PROC(_kern_ipc, OID_AUTO, msqids, CTLFLAG_RD,
1292 NULL, 0, sysctl_msqids, "", "Message queue IDs");