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 172930 2007-10-24 19:04:04Z rwatson $");
|
| 51__FBSDID("$FreeBSD: head/sys/kern/sysv_msg.c 192895 2009-05-27 14:11:23Z jamie $"); |
52
53#include "opt_sysvipc.h"
54#include "opt_mac.h"
55
56#include <sys/param.h>
57#include <sys/systm.h>
58#include <sys/sysproto.h>
59#include <sys/kernel.h>
60#include <sys/priv.h>
61#include <sys/proc.h>
62#include <sys/lock.h>
63#include <sys/mutex.h>
64#include <sys/module.h>
65#include <sys/msg.h>
66#include <sys/syscall.h>
67#include <sys/syscallsubr.h>
68#include <sys/sysent.h>
69#include <sys/sysctl.h>
70#include <sys/malloc.h>
71#include <sys/jail.h>
72
73#include <security/mac/mac_framework.h>
74
75static MALLOC_DEFINE(M_MSG, "msg", "SVID compatible message queues");
76
77static void msginit(void);
78static int msgunload(void);
79static int sysvmsg_modload(struct module *, int, void *);
80
81#ifdef MSG_DEBUG
82#define DPRINTF(a) printf a
83#else
84#define DPRINTF(a)
85#endif
86
87static void msg_freehdr(struct msg *msghdr);
88
89/* XXX casting to (sy_call_t *) is bogus, as usual. */
90static sy_call_t *msgcalls[] = {
91 (sy_call_t *)msgctl, (sy_call_t *)msgget,
92 (sy_call_t *)msgsnd, (sy_call_t *)msgrcv
93};
94
95#ifndef MSGSSZ
96#define MSGSSZ 8 /* Each segment must be 2^N long */
97#endif
98#ifndef MSGSEG
99#define MSGSEG 2048 /* must be less than 32767 */
100#endif
101#define MSGMAX (MSGSSZ*MSGSEG)
102#ifndef MSGMNB
103#define MSGMNB 2048 /* max # of bytes in a queue */
104#endif
105#ifndef MSGMNI
106#define MSGMNI 40
107#endif
108#ifndef MSGTQL
109#define MSGTQL 40
110#endif
111
112/*
113 * Based on the configuration parameters described in an SVR2 (yes, two)
114 * config(1m) man page.
115 *
116 * Each message is broken up and stored in segments that are msgssz bytes
117 * long. For efficiency reasons, this should be a power of two. Also,
118 * it doesn't make sense if it is less than 8 or greater than about 256.
119 * Consequently, msginit in kern/sysv_msg.c checks that msgssz is a power of
120 * two between 8 and 1024 inclusive (and panic's if it isn't).
121 */
122struct msginfo msginfo = {
123 MSGMAX, /* max chars in a message */
124 MSGMNI, /* # of message queue identifiers */
125 MSGMNB, /* max chars in a queue */
126 MSGTQL, /* max messages in system */
127 MSGSSZ, /* size of a message segment */
128 /* (must be small power of 2 greater than 4) */
129 MSGSEG /* number of message segments */
130};
131
132/*
133 * macros to convert between msqid_ds's and msqid's.
134 * (specific to this implementation)
135 */
136#define MSQID(ix,ds) ((ix) & 0xffff | (((ds).msg_perm.seq << 16) & 0xffff0000))
137#define MSQID_IX(id) ((id) & 0xffff)
138#define MSQID_SEQ(id) (((id) >> 16) & 0xffff)
139
140/*
141 * The rest of this file is specific to this particular implementation.
142 */
143
144struct msgmap {
145 short next; /* next segment in buffer */
146 /* -1 -> available */
147 /* 0..(MSGSEG-1) -> index of next segment */
148};
149
150#define MSG_LOCKED 01000 /* Is this msqid_ds locked? */
151
152static int nfree_msgmaps; /* # of free map entries */
153static short free_msgmaps; /* head of linked list of free map entries */
154static struct msg *free_msghdrs;/* list of free msg headers */
155static char *msgpool; /* MSGMAX byte long msg buffer pool */
156static struct msgmap *msgmaps; /* MSGSEG msgmap structures */
157static struct msg *msghdrs; /* MSGTQL msg headers */
158static struct msqid_kernel *msqids; /* MSGMNI msqid_kernel struct's */
159static struct mtx msq_mtx; /* global mutex for message queues. */
160
161static void
162msginit()
163{
164 register int i;
165
166 TUNABLE_INT_FETCH("kern.ipc.msgseg", &msginfo.msgseg);
167 TUNABLE_INT_FETCH("kern.ipc.msgssz", &msginfo.msgssz);
168 msginfo.msgmax = msginfo.msgseg * msginfo.msgssz;
169 TUNABLE_INT_FETCH("kern.ipc.msgmni", &msginfo.msgmni);
170 TUNABLE_INT_FETCH("kern.ipc.msgmnb", &msginfo.msgmnb);
171 TUNABLE_INT_FETCH("kern.ipc.msgtql", &msginfo.msgtql);
172
173 msgpool = malloc(msginfo.msgmax, M_MSG, M_WAITOK);
174 if (msgpool == NULL)
175 panic("msgpool is NULL");
176 msgmaps = malloc(sizeof(struct msgmap) * msginfo.msgseg, M_MSG, M_WAITOK);
177 if (msgmaps == NULL)
178 panic("msgmaps is NULL");
179 msghdrs = malloc(sizeof(struct msg) * msginfo.msgtql, M_MSG, M_WAITOK);
180 if (msghdrs == NULL)
181 panic("msghdrs is NULL");
182 msqids = malloc(sizeof(struct msqid_kernel) * msginfo.msgmni, M_MSG,
183 M_WAITOK);
184 if (msqids == NULL)
185 panic("msqids is NULL");
186
187 /*
188 * msginfo.msgssz should be a power of two for efficiency reasons.
189 * It is also pretty silly if msginfo.msgssz is less than 8
190 * or greater than about 256 so ...
191 */
192
193 i = 8;
194 while (i < 1024 && i != msginfo.msgssz)
195 i <<= 1;
196 if (i != msginfo.msgssz) {
197 DPRINTF(("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz,
198 msginfo.msgssz));
199 panic("msginfo.msgssz not a small power of 2");
200 }
201
202 if (msginfo.msgseg > 32767) {
203 DPRINTF(("msginfo.msgseg=%d\n", msginfo.msgseg));
204 panic("msginfo.msgseg > 32767");
205 }
206
207 if (msgmaps == NULL)
208 panic("msgmaps is NULL");
209
210 for (i = 0; i < msginfo.msgseg; i++) {
211 if (i > 0)
212 msgmaps[i-1].next = i;
213 msgmaps[i].next = -1; /* implies entry is available */
214 }
215 free_msgmaps = 0;
216 nfree_msgmaps = msginfo.msgseg;
217
218 if (msghdrs == NULL)
219 panic("msghdrs is NULL");
220
221 for (i = 0; i < msginfo.msgtql; i++) {
222 msghdrs[i].msg_type = 0;
223 if (i > 0)
224 msghdrs[i-1].msg_next = &msghdrs[i];
225 msghdrs[i].msg_next = NULL;
226#ifdef MAC
227 mac_sysvmsg_init(&msghdrs[i]);
228#endif
229 }
230 free_msghdrs = &msghdrs[0];
231
232 if (msqids == NULL)
233 panic("msqids is NULL");
234
235 for (i = 0; i < msginfo.msgmni; i++) {
236 msqids[i].u.msg_qbytes = 0; /* implies entry is available */
237 msqids[i].u.msg_perm.seq = 0; /* reset to a known value */
238 msqids[i].u.msg_perm.mode = 0;
239#ifdef MAC
240 mac_sysvmsq_init(&msqids[i]);
241#endif
242 }
243 mtx_init(&msq_mtx, "msq", NULL, MTX_DEF);
244}
245
246static int
247msgunload()
248{
249 struct msqid_kernel *msqkptr;
250 int msqid;
251#ifdef MAC
252 int i;
253#endif
254
255 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
256 /*
257 * Look for an unallocated and unlocked msqid_ds.
258 * msqid_ds's can be locked by msgsnd or msgrcv while
259 * they are copying the message in/out. We can't
260 * re-use the entry until they release it.
261 */
262 msqkptr = &msqids[msqid];
263 if (msqkptr->u.msg_qbytes != 0 ||
264 (msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0)
265 break;
266 }
267 if (msqid != msginfo.msgmni)
268 return (EBUSY);
269
270#ifdef MAC
271 for (i = 0; i < msginfo.msgtql; i++)
272 mac_sysvmsg_destroy(&msghdrs[i]);
273 for (msqid = 0; msqid < msginfo.msgmni; msqid++)
274 mac_sysvmsq_destroy(&msqids[msqid]);
275#endif
276 free(msgpool, M_MSG);
277 free(msgmaps, M_MSG);
278 free(msghdrs, M_MSG);
279 free(msqids, M_MSG);
280 mtx_destroy(&msq_mtx);
281 return (0);
282}
283
284
285static int
286sysvmsg_modload(struct module *module, int cmd, void *arg)
287{
288 int error = 0;
289
290 switch (cmd) {
291 case MOD_LOAD:
292 msginit();
293 break;
294 case MOD_UNLOAD:
295 error = msgunload();
296 break;
297 case MOD_SHUTDOWN:
298 break;
299 default:
300 error = EINVAL;
301 break;
302 }
303 return (error);
304}
305
306static moduledata_t sysvmsg_mod = {
307 "sysvmsg",
308 &sysvmsg_modload,
309 NULL
310};
311
312SYSCALL_MODULE_HELPER(msgsys);
313SYSCALL_MODULE_HELPER(msgctl);
314SYSCALL_MODULE_HELPER(msgget);
315SYSCALL_MODULE_HELPER(msgsnd);
316SYSCALL_MODULE_HELPER(msgrcv);
317
318DECLARE_MODULE(sysvmsg, sysvmsg_mod,
319 SI_SUB_SYSV_MSG, SI_ORDER_FIRST);
320MODULE_VERSION(sysvmsg, 1);
321
322/*
323 * Entry point for all MSG calls.
324 */
325int
326msgsys(td, uap)
327 struct thread *td;
328 /* XXX actually varargs. */
329 struct msgsys_args /* {
330 int which;
331 int a2;
332 int a3;
333 int a4;
334 int a5;
335 int a6;
336 } */ *uap;
337{
338 int error;
339
|
340 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
|
| 340 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) |
341 return (ENOSYS);
342 if (uap->which < 0 ||
343 uap->which >= sizeof(msgcalls)/sizeof(msgcalls[0]))
344 return (EINVAL);
345 error = (*msgcalls[uap->which])(td, &uap->a2);
346 return (error);
347}
348
349static void
350msg_freehdr(msghdr)
351 struct msg *msghdr;
352{
353 while (msghdr->msg_ts > 0) {
354 short next;
355 if (msghdr->msg_spot < 0 || msghdr->msg_spot >= msginfo.msgseg)
356 panic("msghdr->msg_spot out of range");
357 next = msgmaps[msghdr->msg_spot].next;
358 msgmaps[msghdr->msg_spot].next = free_msgmaps;
359 free_msgmaps = msghdr->msg_spot;
360 nfree_msgmaps++;
361 msghdr->msg_spot = next;
362 if (msghdr->msg_ts >= msginfo.msgssz)
363 msghdr->msg_ts -= msginfo.msgssz;
364 else
365 msghdr->msg_ts = 0;
366 }
367 if (msghdr->msg_spot != -1)
368 panic("msghdr->msg_spot != -1");
369 msghdr->msg_next = free_msghdrs;
370 free_msghdrs = msghdr;
371#ifdef MAC
372 mac_sysvmsg_cleanup(msghdr);
373#endif
374}
375
376#ifndef _SYS_SYSPROTO_H_
377struct msgctl_args {
378 int msqid;
379 int cmd;
380 struct msqid_ds *buf;
381};
382#endif
383int
384msgctl(td, uap)
385 struct thread *td;
386 register struct msgctl_args *uap;
387{
388 int msqid = uap->msqid;
389 int cmd = uap->cmd;
390 struct msqid_ds msqbuf;
391 int error;
392
393 DPRINTF(("call to msgctl(%d, %d, %p)\n", msqid, cmd, uap->buf));
394 if (cmd == IPC_SET &&
395 (error = copyin(uap->buf, &msqbuf, sizeof(msqbuf))) != 0)
396 return (error);
397 error = kern_msgctl(td, msqid, cmd, &msqbuf);
398 if (cmd == IPC_STAT && error == 0)
399 error = copyout(&msqbuf, uap->buf, sizeof(struct msqid_ds));
400 return (error);
401}
402
403int
404kern_msgctl(td, msqid, cmd, msqbuf)
405 struct thread *td;
406 int msqid;
407 int cmd;
408 struct msqid_ds *msqbuf;
409{
410 int rval, error, msqix;
411 register struct msqid_kernel *msqkptr;
412
|
413 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
|
| 413 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) |
414 return (ENOSYS);
415
416 msqix = IPCID_TO_IX(msqid);
417
418 if (msqix < 0 || msqix >= msginfo.msgmni) {
419 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
420 msginfo.msgmni));
421 return (EINVAL);
422 }
423
424 msqkptr = &msqids[msqix];
425
426 mtx_lock(&msq_mtx);
427 if (msqkptr->u.msg_qbytes == 0) {
428 DPRINTF(("no such msqid\n"));
429 error = EINVAL;
430 goto done2;
431 }
432 if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
433 DPRINTF(("wrong sequence number\n"));
434 error = EINVAL;
435 goto done2;
436 }
437#ifdef MAC
438 error = mac_sysvmsq_check_msqctl(td->td_ucred, msqkptr, cmd);
439 if (error != 0)
440 goto done2;
441#endif
442
443 error = 0;
444 rval = 0;
445
446 switch (cmd) {
447
448 case IPC_RMID:
449 {
450 struct msg *msghdr;
451 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M)))
452 goto done2;
453
454#ifdef MAC
455 /*
456 * Check that the thread has MAC access permissions to
457 * individual msghdrs. Note: We need to do this in a
458 * separate loop because the actual loop alters the
459 * msq/msghdr info as it progresses, and there is no going
460 * back if half the way through we discover that the
461 * thread cannot free a certain msghdr. The msq will get
462 * into an inconsistent state.
463 */
464 for (msghdr = msqkptr->u.msg_first; msghdr != NULL;
465 msghdr = msghdr->msg_next) {
466 error = mac_sysvmsq_check_msgrmid(td->td_ucred, msghdr);
467 if (error != 0)
468 goto done2;
469 }
470#endif
471
472 /* Free the message headers */
473 msghdr = msqkptr->u.msg_first;
474 while (msghdr != NULL) {
475 struct msg *msghdr_tmp;
476
477 /* Free the segments of each message */
478 msqkptr->u.msg_cbytes -= msghdr->msg_ts;
479 msqkptr->u.msg_qnum--;
480 msghdr_tmp = msghdr;
481 msghdr = msghdr->msg_next;
482 msg_freehdr(msghdr_tmp);
483 }
484
485 if (msqkptr->u.msg_cbytes != 0)
486 panic("msg_cbytes is screwed up");
487 if (msqkptr->u.msg_qnum != 0)
488 panic("msg_qnum is screwed up");
489
490 msqkptr->u.msg_qbytes = 0; /* Mark it as free */
491
492#ifdef MAC
493 mac_sysvmsq_cleanup(msqkptr);
494#endif
495
496 wakeup(msqkptr);
497 }
498
499 break;
500
501 case IPC_SET:
502 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M)))
503 goto done2;
504 if (msqbuf->msg_qbytes > msqkptr->u.msg_qbytes) {
505 error = priv_check(td, PRIV_IPC_MSGSIZE);
506 if (error)
507 goto done2;
508 }
509 if (msqbuf->msg_qbytes > msginfo.msgmnb) {
510 DPRINTF(("can't increase msg_qbytes beyond %d"
511 "(truncating)\n", msginfo.msgmnb));
512 msqbuf->msg_qbytes = msginfo.msgmnb; /* silently restrict qbytes to system limit */
513 }
514 if (msqbuf->msg_qbytes == 0) {
515 DPRINTF(("can't reduce msg_qbytes to 0\n"));
516 error = EINVAL; /* non-standard errno! */
517 goto done2;
518 }
519 msqkptr->u.msg_perm.uid = msqbuf->msg_perm.uid; /* change the owner */
520 msqkptr->u.msg_perm.gid = msqbuf->msg_perm.gid; /* change the owner */
521 msqkptr->u.msg_perm.mode = (msqkptr->u.msg_perm.mode & ~0777) |
522 (msqbuf->msg_perm.mode & 0777);
523 msqkptr->u.msg_qbytes = msqbuf->msg_qbytes;
524 msqkptr->u.msg_ctime = time_second;
525 break;
526
527 case IPC_STAT:
528 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) {
529 DPRINTF(("requester doesn't have read access\n"));
530 goto done2;
531 }
532 *msqbuf = msqkptr->u;
533 break;
534
535 default:
536 DPRINTF(("invalid command %d\n", cmd));
537 error = EINVAL;
538 goto done2;
539 }
540
541 if (error == 0)
542 td->td_retval[0] = rval;
543done2:
544 mtx_unlock(&msq_mtx);
545 return (error);
546}
547
548#ifndef _SYS_SYSPROTO_H_
549struct msgget_args {
550 key_t key;
551 int msgflg;
552};
553#endif
554int
555msgget(td, uap)
556 struct thread *td;
557 register struct msgget_args *uap;
558{
559 int msqid, error = 0;
560 int key = uap->key;
561 int msgflg = uap->msgflg;
562 struct ucred *cred = td->td_ucred;
563 register struct msqid_kernel *msqkptr = NULL;
564
565 DPRINTF(("msgget(0x%x, 0%o)\n", key, msgflg));
566
|
567 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
|
| 567 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) |
568 return (ENOSYS);
569
570 mtx_lock(&msq_mtx);
571 if (key != IPC_PRIVATE) {
572 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
573 msqkptr = &msqids[msqid];
574 if (msqkptr->u.msg_qbytes != 0 &&
575 msqkptr->u.msg_perm.key == key)
576 break;
577 }
578 if (msqid < msginfo.msgmni) {
579 DPRINTF(("found public key\n"));
580 if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) {
581 DPRINTF(("not exclusive\n"));
582 error = EEXIST;
583 goto done2;
584 }
585 if ((error = ipcperm(td, &msqkptr->u.msg_perm,
586 msgflg & 0700))) {
587 DPRINTF(("requester doesn't have 0%o access\n",
588 msgflg & 0700));
589 goto done2;
590 }
591#ifdef MAC
592 error = mac_sysvmsq_check_msqget(cred, msqkptr);
593 if (error != 0)
594 goto done2;
595#endif
596 goto found;
597 }
598 }
599
600 DPRINTF(("need to allocate the msqid_ds\n"));
601 if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) {
602 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
603 /*
604 * Look for an unallocated and unlocked msqid_ds.
605 * msqid_ds's can be locked by msgsnd or msgrcv while
606 * they are copying the message in/out. We can't
607 * re-use the entry until they release it.
608 */
609 msqkptr = &msqids[msqid];
610 if (msqkptr->u.msg_qbytes == 0 &&
611 (msqkptr->u.msg_perm.mode & MSG_LOCKED) == 0)
612 break;
613 }
614 if (msqid == msginfo.msgmni) {
615 DPRINTF(("no more msqid_ds's available\n"));
616 error = ENOSPC;
617 goto done2;
618 }
619 DPRINTF(("msqid %d is available\n", msqid));
620 msqkptr->u.msg_perm.key = key;
621 msqkptr->u.msg_perm.cuid = cred->cr_uid;
622 msqkptr->u.msg_perm.uid = cred->cr_uid;
623 msqkptr->u.msg_perm.cgid = cred->cr_gid;
624 msqkptr->u.msg_perm.gid = cred->cr_gid;
625 msqkptr->u.msg_perm.mode = (msgflg & 0777);
626 /* Make sure that the returned msqid is unique */
627 msqkptr->u.msg_perm.seq = (msqkptr->u.msg_perm.seq + 1) & 0x7fff;
628 msqkptr->u.msg_first = NULL;
629 msqkptr->u.msg_last = NULL;
630 msqkptr->u.msg_cbytes = 0;
631 msqkptr->u.msg_qnum = 0;
632 msqkptr->u.msg_qbytes = msginfo.msgmnb;
633 msqkptr->u.msg_lspid = 0;
634 msqkptr->u.msg_lrpid = 0;
635 msqkptr->u.msg_stime = 0;
636 msqkptr->u.msg_rtime = 0;
637 msqkptr->u.msg_ctime = time_second;
638#ifdef MAC
639 mac_sysvmsq_create(cred, msqkptr);
640#endif
641 } else {
642 DPRINTF(("didn't find it and wasn't asked to create it\n"));
643 error = ENOENT;
644 goto done2;
645 }
646
647found:
648 /* Construct the unique msqid */
649 td->td_retval[0] = IXSEQ_TO_IPCID(msqid, msqkptr->u.msg_perm);
650done2:
651 mtx_unlock(&msq_mtx);
652 return (error);
653}
654
655#ifndef _SYS_SYSPROTO_H_
656struct msgsnd_args {
657 int msqid;
658 const void *msgp;
659 size_t msgsz;
660 int msgflg;
661};
662#endif
663int
664kern_msgsnd(td, msqid, msgp, msgsz, msgflg, mtype)
665 struct thread *td;
666 int msqid;
667 const void *msgp; /* XXX msgp is actually mtext. */
668 size_t msgsz;
669 int msgflg;
670 long mtype;
671{
672 int msqix, segs_needed, error = 0;
673 register struct msqid_kernel *msqkptr;
674 register struct msg *msghdr;
675 short next;
676
|
677 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
|
| 677 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) |
678 return (ENOSYS);
679
680 mtx_lock(&msq_mtx);
681 msqix = IPCID_TO_IX(msqid);
682
683 if (msqix < 0 || msqix >= msginfo.msgmni) {
684 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
685 msginfo.msgmni));
686 error = EINVAL;
687 goto done2;
688 }
689
690 msqkptr = &msqids[msqix];
691 if (msqkptr->u.msg_qbytes == 0) {
692 DPRINTF(("no such message queue id\n"));
693 error = EINVAL;
694 goto done2;
695 }
696 if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
697 DPRINTF(("wrong sequence number\n"));
698 error = EINVAL;
699 goto done2;
700 }
701
702 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_W))) {
703 DPRINTF(("requester doesn't have write access\n"));
704 goto done2;
705 }
706
707#ifdef MAC
708 error = mac_sysvmsq_check_msqsnd(td->td_ucred, msqkptr);
709 if (error != 0)
710 goto done2;
711#endif
712
713 segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz;
714 DPRINTF(("msgsz=%zu, msgssz=%d, segs_needed=%d\n", msgsz,
715 msginfo.msgssz, segs_needed));
716 for (;;) {
717 int need_more_resources = 0;
718
719 /*
720 * check msgsz
721 * (inside this loop in case msg_qbytes changes while we sleep)
722 */
723
724 if (msgsz > msqkptr->u.msg_qbytes) {
725 DPRINTF(("msgsz > msqkptr->u.msg_qbytes\n"));
726 error = EINVAL;
727 goto done2;
728 }
729
730 if (msqkptr->u.msg_perm.mode & MSG_LOCKED) {
731 DPRINTF(("msqid is locked\n"));
732 need_more_resources = 1;
733 }
734 if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes) {
735 DPRINTF(("msgsz + msg_cbytes > msg_qbytes\n"));
736 need_more_resources = 1;
737 }
738 if (segs_needed > nfree_msgmaps) {
739 DPRINTF(("segs_needed > nfree_msgmaps\n"));
740 need_more_resources = 1;
741 }
742 if (free_msghdrs == NULL) {
743 DPRINTF(("no more msghdrs\n"));
744 need_more_resources = 1;
745 }
746
747 if (need_more_resources) {
748 int we_own_it;
749
750 if ((msgflg & IPC_NOWAIT) != 0) {
751 DPRINTF(("need more resources but caller "
752 "doesn't want to wait\n"));
753 error = EAGAIN;
754 goto done2;
755 }
756
757 if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0) {
758 DPRINTF(("we don't own the msqid_ds\n"));
759 we_own_it = 0;
760 } else {
761 /* Force later arrivals to wait for our
762 request */
763 DPRINTF(("we own the msqid_ds\n"));
764 msqkptr->u.msg_perm.mode |= MSG_LOCKED;
765 we_own_it = 1;
766 }
767 DPRINTF(("msgsnd: goodnight\n"));
768 error = msleep(msqkptr, &msq_mtx, (PZERO - 4) | PCATCH,
769 "msgsnd", hz);
770 DPRINTF(("msgsnd: good morning, error=%d\n", error));
771 if (we_own_it)
772 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
773 if (error == EWOULDBLOCK) {
774 DPRINTF(("msgsnd: timed out\n"));
775 continue;
776 }
777 if (error != 0) {
778 DPRINTF(("msgsnd: interrupted system call\n"));
779 error = EINTR;
780 goto done2;
781 }
782
783 /*
784 * Make sure that the msq queue still exists
785 */
786
787 if (msqkptr->u.msg_qbytes == 0) {
788 DPRINTF(("msqid deleted\n"));
789 error = EIDRM;
790 goto done2;
791 }
792
793 } else {
794 DPRINTF(("got all the resources that we need\n"));
795 break;
796 }
797 }
798
799 /*
800 * We have the resources that we need.
801 * Make sure!
802 */
803
804 if (msqkptr->u.msg_perm.mode & MSG_LOCKED)
805 panic("msg_perm.mode & MSG_LOCKED");
806 if (segs_needed > nfree_msgmaps)
807 panic("segs_needed > nfree_msgmaps");
808 if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes)
809 panic("msgsz + msg_cbytes > msg_qbytes");
810 if (free_msghdrs == NULL)
811 panic("no more msghdrs");
812
813 /*
814 * Re-lock the msqid_ds in case we page-fault when copying in the
815 * message
816 */
817
818 if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0)
819 panic("msqid_ds is already locked");
820 msqkptr->u.msg_perm.mode |= MSG_LOCKED;
821
822 /*
823 * Allocate a message header
824 */
825
826 msghdr = free_msghdrs;
827 free_msghdrs = msghdr->msg_next;
828 msghdr->msg_spot = -1;
829 msghdr->msg_ts = msgsz;
830 msghdr->msg_type = mtype;
831#ifdef MAC
832 /*
833 * XXXMAC: Should the mac_sysvmsq_check_msgmsq check follow here
834 * immediately? Or, should it be checked just before the msg is
835 * enqueued in the msgq (as it is done now)?
836 */
837 mac_sysvmsg_create(td->td_ucred, msqkptr, msghdr);
838#endif
839
840 /*
841 * Allocate space for the message
842 */
843
844 while (segs_needed > 0) {
845 if (nfree_msgmaps <= 0)
846 panic("not enough msgmaps");
847 if (free_msgmaps == -1)
848 panic("nil free_msgmaps");
849 next = free_msgmaps;
850 if (next <= -1)
851 panic("next too low #1");
852 if (next >= msginfo.msgseg)
853 panic("next out of range #1");
854 DPRINTF(("allocating segment %d to message\n", next));
855 free_msgmaps = msgmaps[next].next;
856 nfree_msgmaps--;
857 msgmaps[next].next = msghdr->msg_spot;
858 msghdr->msg_spot = next;
859 segs_needed--;
860 }
861
862 /*
863 * Validate the message type
864 */
865
866 if (msghdr->msg_type < 1) {
867 msg_freehdr(msghdr);
868 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
869 wakeup(msqkptr);
870 DPRINTF(("mtype (%ld) < 1\n", msghdr->msg_type));
871 error = EINVAL;
872 goto done2;
873 }
874
875 /*
876 * Copy in the message body
877 */
878
879 next = msghdr->msg_spot;
880 while (msgsz > 0) {
881 size_t tlen;
882 if (msgsz > msginfo.msgssz)
883 tlen = msginfo.msgssz;
884 else
885 tlen = msgsz;
886 if (next <= -1)
887 panic("next too low #2");
888 if (next >= msginfo.msgseg)
889 panic("next out of range #2");
890 mtx_unlock(&msq_mtx);
891 if ((error = copyin(msgp, &msgpool[next * msginfo.msgssz],
892 tlen)) != 0) {
893 mtx_lock(&msq_mtx);
894 DPRINTF(("error %d copying in message segment\n",
895 error));
896 msg_freehdr(msghdr);
897 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
898 wakeup(msqkptr);
899 goto done2;
900 }
901 mtx_lock(&msq_mtx);
902 msgsz -= tlen;
903 msgp = (const char *)msgp + tlen;
904 next = msgmaps[next].next;
905 }
906 if (next != -1)
907 panic("didn't use all the msg segments");
908
909 /*
910 * We've got the message. Unlock the msqid_ds.
911 */
912
913 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
914
915 /*
916 * Make sure that the msqid_ds is still allocated.
917 */
918
919 if (msqkptr->u.msg_qbytes == 0) {
920 msg_freehdr(msghdr);
921 wakeup(msqkptr);
922 error = EIDRM;
923 goto done2;
924 }
925
926#ifdef MAC
927 /*
928 * Note: Since the task/thread allocates the msghdr and usually
929 * primes it with its own MAC label, for a majority of policies, it
930 * won't be necessary to check whether the msghdr has access
931 * permissions to the msgq. The mac_sysvmsq_check_msqsnd check would
932 * suffice in that case. However, this hook may be required where
933 * individual policies derive a non-identical label for the msghdr
934 * from the current thread label and may want to check the msghdr
935 * enqueue permissions, along with read/write permissions to the
936 * msgq.
937 */
938 error = mac_sysvmsq_check_msgmsq(td->td_ucred, msghdr, msqkptr);
939 if (error != 0) {
940 msg_freehdr(msghdr);
941 wakeup(msqkptr);
942 goto done2;
943 }
944#endif
945
946 /*
947 * Put the message into the queue
948 */
949 if (msqkptr->u.msg_first == NULL) {
950 msqkptr->u.msg_first = msghdr;
951 msqkptr->u.msg_last = msghdr;
952 } else {
953 msqkptr->u.msg_last->msg_next = msghdr;
954 msqkptr->u.msg_last = msghdr;
955 }
956 msqkptr->u.msg_last->msg_next = NULL;
957
958 msqkptr->u.msg_cbytes += msghdr->msg_ts;
959 msqkptr->u.msg_qnum++;
960 msqkptr->u.msg_lspid = td->td_proc->p_pid;
961 msqkptr->u.msg_stime = time_second;
962
963 wakeup(msqkptr);
964 td->td_retval[0] = 0;
965done2:
966 mtx_unlock(&msq_mtx);
967 return (error);
968}
969
970int
971msgsnd(td, uap)
972 struct thread *td;
973 register struct msgsnd_args *uap;
974{
975 int error;
976 long mtype;
977
978 DPRINTF(("call to msgsnd(%d, %p, %zu, %d)\n", uap->msqid, uap->msgp,
979 uap->msgsz, uap->msgflg));
980
981 if ((error = copyin(uap->msgp, &mtype, sizeof(mtype))) != 0) {
982 DPRINTF(("error %d copying the message type\n", error));
983 return (error);
984 }
985 return (kern_msgsnd(td, uap->msqid,
986 (const char *)uap->msgp + sizeof(mtype),
987 uap->msgsz, uap->msgflg, mtype));
988}
989
990#ifndef _SYS_SYSPROTO_H_
991struct msgrcv_args {
992 int msqid;
993 void *msgp;
994 size_t msgsz;
995 long msgtyp;
996 int msgflg;
997};
998#endif
999int
1000kern_msgrcv(td, msqid, msgp, msgsz, msgtyp, msgflg, mtype)
1001 struct thread *td;
1002 int msqid;
1003 void *msgp; /* XXX msgp is actually mtext. */
1004 size_t msgsz;
1005 long msgtyp;
1006 int msgflg;
1007 long *mtype;
1008{
1009 size_t len;
1010 register struct msqid_kernel *msqkptr;
1011 register struct msg *msghdr;
1012 int msqix, error = 0;
1013 short next;
1014
|
1015 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
|
| 1015 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) |
1016 return (ENOSYS);
1017
1018 msqix = IPCID_TO_IX(msqid);
1019
1020 if (msqix < 0 || msqix >= msginfo.msgmni) {
1021 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
1022 msginfo.msgmni));
1023 return (EINVAL);
1024 }
1025
1026 msqkptr = &msqids[msqix];
1027 mtx_lock(&msq_mtx);
1028 if (msqkptr->u.msg_qbytes == 0) {
1029 DPRINTF(("no such message queue id\n"));
1030 error = EINVAL;
1031 goto done2;
1032 }
1033 if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
1034 DPRINTF(("wrong sequence number\n"));
1035 error = EINVAL;
1036 goto done2;
1037 }
1038
1039 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) {
1040 DPRINTF(("requester doesn't have read access\n"));
1041 goto done2;
1042 }
1043
1044#ifdef MAC
1045 error = mac_sysvmsq_check_msqrcv(td->td_ucred, msqkptr);
1046 if (error != 0)
1047 goto done2;
1048#endif
1049
1050 msghdr = NULL;
1051 while (msghdr == NULL) {
1052 if (msgtyp == 0) {
1053 msghdr = msqkptr->u.msg_first;
1054 if (msghdr != NULL) {
1055 if (msgsz < msghdr->msg_ts &&
1056 (msgflg & MSG_NOERROR) == 0) {
1057 DPRINTF(("first message on the queue "
1058 "is too big (want %zu, got %d)\n",
1059 msgsz, msghdr->msg_ts));
1060 error = E2BIG;
1061 goto done2;
1062 }
1063#ifdef MAC
1064 error = mac_sysvmsq_check_msgrcv(td->td_ucred,
1065 msghdr);
1066 if (error != 0)
1067 goto done2;
1068#endif
1069 if (msqkptr->u.msg_first == msqkptr->u.msg_last) {
1070 msqkptr->u.msg_first = NULL;
1071 msqkptr->u.msg_last = NULL;
1072 } else {
1073 msqkptr->u.msg_first = msghdr->msg_next;
1074 if (msqkptr->u.msg_first == NULL)
1075 panic("msg_first/last screwed up #1");
1076 }
1077 }
1078 } else {
1079 struct msg *previous;
1080 struct msg **prev;
1081
1082 previous = NULL;
1083 prev = &(msqkptr->u.msg_first);
1084 while ((msghdr = *prev) != NULL) {
1085 /*
1086 * Is this message's type an exact match or is
1087 * this message's type less than or equal to
1088 * the absolute value of a negative msgtyp?
1089 * Note that the second half of this test can
1090 * NEVER be true if msgtyp is positive since
1091 * msg_type is always positive!
1092 */
1093
1094 if (msgtyp == msghdr->msg_type ||
1095 msghdr->msg_type <= -msgtyp) {
1096 DPRINTF(("found message type %ld, "
1097 "requested %ld\n",
1098 msghdr->msg_type, msgtyp));
1099 if (msgsz < msghdr->msg_ts &&
1100 (msgflg & MSG_NOERROR) == 0) {
1101 DPRINTF(("requested message "
1102 "on the queue is too big "
1103 "(want %zu, got %hu)\n",
1104 msgsz, msghdr->msg_ts));
1105 error = E2BIG;
1106 goto done2;
1107 }
1108#ifdef MAC
1109 error = mac_sysvmsq_check_msgrcv(
1110 td->td_ucred, msghdr);
1111 if (error != 0)
1112 goto done2;
1113#endif
1114 *prev = msghdr->msg_next;
1115 if (msghdr == msqkptr->u.msg_last) {
1116 if (previous == NULL) {
1117 if (prev !=
1118 &msqkptr->u.msg_first)
1119 panic("msg_first/last screwed up #2");
1120 msqkptr->u.msg_first =
1121 NULL;
1122 msqkptr->u.msg_last =
1123 NULL;
1124 } else {
1125 if (prev ==
1126 &msqkptr->u.msg_first)
1127 panic("msg_first/last screwed up #3");
1128 msqkptr->u.msg_last =
1129 previous;
1130 }
1131 }
1132 break;
1133 }
1134 previous = msghdr;
1135 prev = &(msghdr->msg_next);
1136 }
1137 }
1138
1139 /*
1140 * We've either extracted the msghdr for the appropriate
1141 * message or there isn't one.
1142 * If there is one then bail out of this loop.
1143 */
1144
1145 if (msghdr != NULL)
1146 break;
1147
1148 /*
1149 * Hmph! No message found. Does the user want to wait?
1150 */
1151
1152 if ((msgflg & IPC_NOWAIT) != 0) {
1153 DPRINTF(("no appropriate message found (msgtyp=%ld)\n",
1154 msgtyp));
1155 /* The SVID says to return ENOMSG. */
1156 error = ENOMSG;
1157 goto done2;
1158 }
1159
1160 /*
1161 * Wait for something to happen
1162 */
1163
1164 DPRINTF(("msgrcv: goodnight\n"));
1165 error = msleep(msqkptr, &msq_mtx, (PZERO - 4) | PCATCH,
1166 "msgrcv", 0);
1167 DPRINTF(("msgrcv: good morning (error=%d)\n", error));
1168
1169 if (error != 0) {
1170 DPRINTF(("msgrcv: interrupted system call\n"));
1171 error = EINTR;
1172 goto done2;
1173 }
1174
1175 /*
1176 * Make sure that the msq queue still exists
1177 */
1178
1179 if (msqkptr->u.msg_qbytes == 0 ||
1180 msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
1181 DPRINTF(("msqid deleted\n"));
1182 error = EIDRM;
1183 goto done2;
1184 }
1185 }
1186
1187 /*
1188 * Return the message to the user.
1189 *
1190 * First, do the bookkeeping (before we risk being interrupted).
1191 */
1192
1193 msqkptr->u.msg_cbytes -= msghdr->msg_ts;
1194 msqkptr->u.msg_qnum--;
1195 msqkptr->u.msg_lrpid = td->td_proc->p_pid;
1196 msqkptr->u.msg_rtime = time_second;
1197
1198 /*
1199 * Make msgsz the actual amount that we'll be returning.
1200 * Note that this effectively truncates the message if it is too long
1201 * (since msgsz is never increased).
1202 */
1203
1204 DPRINTF(("found a message, msgsz=%zu, msg_ts=%hu\n", msgsz,
1205 msghdr->msg_ts));
1206 if (msgsz > msghdr->msg_ts)
1207 msgsz = msghdr->msg_ts;
1208 *mtype = msghdr->msg_type;
1209
1210 /*
1211 * Return the segments to the user
1212 */
1213
1214 next = msghdr->msg_spot;
1215 for (len = 0; len < msgsz; len += msginfo.msgssz) {
1216 size_t tlen;
1217
1218 if (msgsz - len > msginfo.msgssz)
1219 tlen = msginfo.msgssz;
1220 else
1221 tlen = msgsz - len;
1222 if (next <= -1)
1223 panic("next too low #3");
1224 if (next >= msginfo.msgseg)
1225 panic("next out of range #3");
1226 mtx_unlock(&msq_mtx);
1227 error = copyout(&msgpool[next * msginfo.msgssz], msgp, tlen);
1228 mtx_lock(&msq_mtx);
1229 if (error != 0) {
1230 DPRINTF(("error (%d) copying out message segment\n",
1231 error));
1232 msg_freehdr(msghdr);
1233 wakeup(msqkptr);
1234 goto done2;
1235 }
1236 msgp = (char *)msgp + tlen;
1237 next = msgmaps[next].next;
1238 }
1239
1240 /*
1241 * Done, return the actual number of bytes copied out.
1242 */
1243
1244 msg_freehdr(msghdr);
1245 wakeup(msqkptr);
1246 td->td_retval[0] = msgsz;
1247done2:
1248 mtx_unlock(&msq_mtx);
1249 return (error);
1250}
1251
1252int
1253msgrcv(td, uap)
1254 struct thread *td;
1255 register struct msgrcv_args *uap;
1256{
1257 int error;
1258 long mtype;
1259
1260 DPRINTF(("call to msgrcv(%d, %p, %zu, %ld, %d)\n", uap->msqid,
1261 uap->msgp, uap->msgsz, uap->msgtyp, uap->msgflg));
1262
1263 if ((error = kern_msgrcv(td, uap->msqid,
1264 (char *)uap->msgp + sizeof(mtype), uap->msgsz,
1265 uap->msgtyp, uap->msgflg, &mtype)) != 0)
1266 return (error);
1267 if ((error = copyout(&mtype, uap->msgp, sizeof(mtype))) != 0)
1268 DPRINTF(("error %d copying the message type\n", error));
1269 return (error);
1270}
1271
1272static int
1273sysctl_msqids(SYSCTL_HANDLER_ARGS)
1274{
1275
1276 return (SYSCTL_OUT(req, msqids,
1277 sizeof(struct msqid_kernel) * msginfo.msgmni));
1278}
1279
1280SYSCTL_INT(_kern_ipc, OID_AUTO, msgmax, CTLFLAG_RD, &msginfo.msgmax, 0,
1281 "Maximum message size");
1282SYSCTL_INT(_kern_ipc, OID_AUTO, msgmni, CTLFLAG_RDTUN, &msginfo.msgmni, 0,
1283 "Number of message queue identifiers");
1284SYSCTL_INT(_kern_ipc, OID_AUTO, msgmnb, CTLFLAG_RDTUN, &msginfo.msgmnb, 0,
1285 "Maximum number of bytes in a queue");
1286SYSCTL_INT(_kern_ipc, OID_AUTO, msgtql, CTLFLAG_RDTUN, &msginfo.msgtql, 0,
1287 "Maximum number of messages in the system");
1288SYSCTL_INT(_kern_ipc, OID_AUTO, msgssz, CTLFLAG_RDTUN, &msginfo.msgssz, 0,
1289 "Size of a message segment");
1290SYSCTL_INT(_kern_ipc, OID_AUTO, msgseg, CTLFLAG_RDTUN, &msginfo.msgseg, 0,
1291 "Number of message segments");
1292SYSCTL_PROC(_kern_ipc, OID_AUTO, msqids, CTLFLAG_RD,
1293 NULL, 0, sysctl_msqids, "", "Message queue IDs");
|