Deleted Added
sdiff udiff text old ( 11626 ) new ( 12819 )
full compact
sysv_msg.c (11626) sysv_msg.c (12819)
1/* $Id: sysv_msg.c,v 1.8 1995/09/09 18:10:06 davidg Exp $ */
1/* $Id: sysv_msg.c,v 1.9 1995/10/21 19:49:57 bde Exp $ */
2
3/*
4 * Implementation of SVID messages
5 *
6 * Author: Daniel Boulet
7 *
8 * Copyright 1993 Daniel Boulet and RTMX Inc.
9 *
10 * This system call was implemented by Daniel Boulet under contract from RTMX.
11 *
12 * Redistribution and use in source forms, with and without modification,
13 * are permitted provided that this entire comment appears intact.
14 *
15 * Redistribution in binary form may occur without any restrictions.
16 * Obviously, it would be nice if you gave credit where credit is due
17 * but requiring it would be too onerous.
18 *
19 * This software is provided ``AS IS'' without any warranties of any kind.
20 */
21
22#include <sys/param.h>
23#include <sys/systm.h>
24#include <sys/sysproto.h>
25#include <sys/kernel.h>
26#include <sys/proc.h>
27#include <sys/msg.h>
28#include <sys/sysent.h>
29
30static void msginit __P((void *));
31SYSINIT(sysv_msg, SI_SUB_SYSV_MSG, SI_ORDER_FIRST, msginit, NULL)
32
33#define MSG_DEBUG
34#undef MSG_DEBUG_OK
35
36struct msgctl_args;
37static int msgctl __P((struct proc *p, struct msgctl_args *uap, int *retval));
38struct msgget_args;
39static int msgget __P((struct proc *p, struct msgget_args *uap, int *retval));
40struct msgsnd_args;
41static int msgsnd __P((struct proc *p, struct msgsnd_args *uap, int *retval));
42struct msgrcv_args;
43static int msgrcv __P((struct proc *p, struct msgrcv_args *uap, int *retval));
44static void msg_freehdr __P((struct msg *msghdr));
45
46/* XXX casting to (sy_call_t *) is bogus, as usual. */
2
3/*
4 * Implementation of SVID messages
5 *
6 * Author: Daniel Boulet
7 *
8 * Copyright 1993 Daniel Boulet and RTMX Inc.
9 *
10 * This system call was implemented by Daniel Boulet under contract from RTMX.
11 *
12 * Redistribution and use in source forms, with and without modification,
13 * are permitted provided that this entire comment appears intact.
14 *
15 * Redistribution in binary form may occur without any restrictions.
16 * Obviously, it would be nice if you gave credit where credit is due
17 * but requiring it would be too onerous.
18 *
19 * This software is provided ``AS IS'' without any warranties of any kind.
20 */
21
22#include <sys/param.h>
23#include <sys/systm.h>
24#include <sys/sysproto.h>
25#include <sys/kernel.h>
26#include <sys/proc.h>
27#include <sys/msg.h>
28#include <sys/sysent.h>
29
30static void msginit __P((void *));
31SYSINIT(sysv_msg, SI_SUB_SYSV_MSG, SI_ORDER_FIRST, msginit, NULL)
32
33#define MSG_DEBUG
34#undef MSG_DEBUG_OK
35
36struct msgctl_args;
37static int msgctl __P((struct proc *p, struct msgctl_args *uap, int *retval));
38struct msgget_args;
39static int msgget __P((struct proc *p, struct msgget_args *uap, int *retval));
40struct msgsnd_args;
41static int msgsnd __P((struct proc *p, struct msgsnd_args *uap, int *retval));
42struct msgrcv_args;
43static int msgrcv __P((struct proc *p, struct msgrcv_args *uap, int *retval));
44static void msg_freehdr __P((struct msg *msghdr));
45
46/* XXX casting to (sy_call_t *) is bogus, as usual. */
47sy_call_t *msgcalls[] = {
47static sy_call_t *msgcalls[] = {
48 (sy_call_t *)msgctl, (sy_call_t *)msgget,
49 (sy_call_t *)msgsnd, (sy_call_t *)msgrcv
50};
51
48 (sy_call_t *)msgctl, (sy_call_t *)msgget,
49 (sy_call_t *)msgsnd, (sy_call_t *)msgrcv
50};
51
52int nfree_msgmaps; /* # of free map entries */
53short free_msgmaps; /* head of linked list of free map entries */
54struct msg *free_msghdrs; /* list of free msg headers */
52static int nfree_msgmaps; /* # of free map entries */
53static short free_msgmaps; /* head of linked list of free map entries */
54static struct msg *free_msghdrs; /* list of free msg headers */
55char *msgpool; /* MSGMAX byte long msg buffer pool */
56struct msgmap *msgmaps; /* MSGSEG msgmap structures */
57struct msg *msghdrs; /* MSGTQL msg headers */
58struct msqid_ds *msqids; /* MSGMNI msqid_ds struct's */
59
60void
61msginit(dummy)
62 void *dummy;
63{
64 register int i;
65
66 /*
67 * msginfo.msgssz should be a power of two for efficiency reasons.
68 * It is also pretty silly if msginfo.msgssz is less than 8
69 * or greater than about 256 so ...
70 */
71
72 i = 8;
73 while (i < 1024 && i != msginfo.msgssz)
74 i <<= 1;
75 if (i != msginfo.msgssz) {
76 printf("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz,
77 msginfo.msgssz);
78 panic("msginfo.msgssz not a small power of 2");
79 }
80
81 if (msginfo.msgseg > 32767) {
82 printf("msginfo.msgseg=%d\n", msginfo.msgseg);
83 panic("msginfo.msgseg > 32767");
84 }
85
86 if (msgmaps == NULL)
87 panic("msgmaps is NULL");
88
89 for (i = 0; i < msginfo.msgseg; i++) {
90 if (i > 0)
91 msgmaps[i-1].next = i;
92 msgmaps[i].next = -1; /* implies entry is available */
93 }
94 free_msgmaps = 0;
95 nfree_msgmaps = msginfo.msgseg;
96
97 if (msghdrs == NULL)
98 panic("msghdrs is NULL");
99
100 for (i = 0; i < msginfo.msgtql; i++) {
101 msghdrs[i].msg_type = 0;
102 if (i > 0)
103 msghdrs[i-1].msg_next = &msghdrs[i];
104 msghdrs[i].msg_next = NULL;
105 }
106 free_msghdrs = &msghdrs[0];
107
108 if (msqids == NULL)
109 panic("msqids is NULL");
110
111 for (i = 0; i < msginfo.msgmni; i++) {
112 msqids[i].msg_qbytes = 0; /* implies entry is available */
113 msqids[i].msg_perm.seq = 0; /* reset to a known value */
114 }
115}
116
117/*
118 * Entry point for all MSG calls
119 */
120int
121msgsys(p, uap, retval)
122 struct proc *p;
123 /* XXX actually varargs. */
124 struct msgsys_args /* {
125 u_int which;
126 int a2;
127 int a3;
128 int a4;
129 int a5;
130 int a6;
131 } */ *uap;
132 int *retval;
133{
134
135 if (uap->which >= sizeof(msgcalls)/sizeof(msgcalls[0]))
136 return (EINVAL);
137 return ((*msgcalls[uap->which])(p, &uap->a2, retval));
138}
139
140static void
141msg_freehdr(msghdr)
142 struct msg *msghdr;
143{
144 while (msghdr->msg_ts > 0) {
145 short next;
146 if (msghdr->msg_spot < 0 || msghdr->msg_spot >= msginfo.msgseg)
147 panic("msghdr->msg_spot out of range");
148 next = msgmaps[msghdr->msg_spot].next;
149 msgmaps[msghdr->msg_spot].next = free_msgmaps;
150 free_msgmaps = msghdr->msg_spot;
151 nfree_msgmaps++;
152 msghdr->msg_spot = next;
153 if (msghdr->msg_ts >= msginfo.msgssz)
154 msghdr->msg_ts -= msginfo.msgssz;
155 else
156 msghdr->msg_ts = 0;
157 }
158 if (msghdr->msg_spot != -1)
159 panic("msghdr->msg_spot != -1");
160 msghdr->msg_next = free_msghdrs;
161 free_msghdrs = msghdr;
162}
163
164struct msgctl_args {
165 int msqid;
166 int cmd;
167 struct msqid_ds *user_msqptr;
168};
169
170static int
171msgctl(p, uap, retval)
172 struct proc *p;
173 register struct msgctl_args *uap;
174 int *retval;
175{
176 int msqid = uap->msqid;
177 int cmd = uap->cmd;
178 struct msqid_ds *user_msqptr = uap->user_msqptr;
179 struct ucred *cred = p->p_ucred;
180 int rval, eval;
181 struct msqid_ds msqbuf;
182 register struct msqid_ds *msqptr;
183
184#ifdef MSG_DEBUG_OK
185 printf("call to msgctl(%d, %d, 0x%x)\n", msqid, cmd, user_msqptr);
186#endif
187
188 msqid = IPCID_TO_IX(msqid);
189
190 if (msqid < 0 || msqid >= msginfo.msgmni) {
191#ifdef MSG_DEBUG_OK
192 printf("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
193 msginfo.msgmni);
194#endif
195 return(EINVAL);
196 }
197
198 msqptr = &msqids[msqid];
199
200 if (msqptr->msg_qbytes == 0) {
201#ifdef MSG_DEBUG_OK
202 printf("no such msqid\n");
203#endif
204 return(EINVAL);
205 }
206 if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
207#ifdef MSG_DEBUG_OK
208 printf("wrong sequence number\n");
209#endif
210 return(EINVAL);
211 }
212
213 eval = 0;
214 rval = 0;
215
216 switch (cmd) {
217
218 case IPC_RMID:
219 {
220 struct msg *msghdr;
221 if ((eval = ipcperm(cred, &msqptr->msg_perm, IPC_M)))
222 return(eval);
223 /* Free the message headers */
224 msghdr = msqptr->msg_first;
225 while (msghdr != NULL) {
226 struct msg *msghdr_tmp;
227
228 /* Free the segments of each message */
229 msqptr->msg_cbytes -= msghdr->msg_ts;
230 msqptr->msg_qnum--;
231 msghdr_tmp = msghdr;
232 msghdr = msghdr->msg_next;
233 msg_freehdr(msghdr_tmp);
234 }
235
236 if (msqptr->msg_cbytes != 0)
237 panic("msg_cbytes is screwed up");
238 if (msqptr->msg_qnum != 0)
239 panic("msg_qnum is screwed up");
240
241 msqptr->msg_qbytes = 0; /* Mark it as free */
242
243 wakeup((caddr_t)msqptr);
244 }
245
246 break;
247
248 case IPC_SET:
249 if ((eval = ipcperm(cred, &msqptr->msg_perm, IPC_M)))
250 return(eval);
251 if ((eval = copyin(user_msqptr, &msqbuf, sizeof(msqbuf))) != 0)
252 return(eval);
253 if (msqbuf.msg_qbytes > msqptr->msg_qbytes && cred->cr_uid != 0)
254 return(EPERM);
255 if (msqbuf.msg_qbytes > msginfo.msgmnb) {
256#ifdef MSG_DEBUG_OK
257 printf("can't increase msg_qbytes beyond %d (truncating)\n",
258 msginfo.msgmnb);
259#endif
260 msqbuf.msg_qbytes = msginfo.msgmnb; /* silently restrict qbytes to system limit */
261 }
262 if (msqbuf.msg_qbytes == 0) {
263#ifdef MSG_DEBUG_OK
264 printf("can't reduce msg_qbytes to 0\n");
265#endif
266 return(EINVAL); /* non-standard errno! */
267 }
268 msqptr->msg_perm.uid = msqbuf.msg_perm.uid; /* change the owner */
269 msqptr->msg_perm.gid = msqbuf.msg_perm.gid; /* change the owner */
270 msqptr->msg_perm.mode = (msqptr->msg_perm.mode & ~0777) |
271 (msqbuf.msg_perm.mode & 0777);
272 msqptr->msg_qbytes = msqbuf.msg_qbytes;
273 msqptr->msg_ctime = time.tv_sec;
274 break;
275
276 case IPC_STAT:
277 if ((eval = ipcperm(cred, &msqptr->msg_perm, IPC_R))) {
278#ifdef MSG_DEBUG_OK
279 printf("requester doesn't have read access\n");
280#endif
281 return(eval);
282 }
283 eval = copyout((caddr_t)msqptr, user_msqptr,
284 sizeof(struct msqid_ds));
285 break;
286
287 default:
288#ifdef MSG_DEBUG_OK
289 printf("invalid command %d\n", cmd);
290#endif
291 return(EINVAL);
292 }
293
294 if (eval == 0)
295 *retval = rval;
296 return(eval);
297}
298
299struct msgget_args {
300 key_t key;
301 int msgflg;
302};
303
304static int
305msgget(p, uap, retval)
306 struct proc *p;
307 register struct msgget_args *uap;
308 int *retval;
309{
310 int msqid, eval;
311 int key = uap->key;
312 int msgflg = uap->msgflg;
313 struct ucred *cred = p->p_ucred;
314 register struct msqid_ds *msqptr = NULL;
315
316#ifdef MSG_DEBUG_OK
317 printf("msgget(0x%x, 0%o)\n", key, msgflg);
318#endif
319
320 if (key != IPC_PRIVATE) {
321 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
322 msqptr = &msqids[msqid];
323 if (msqptr->msg_qbytes != 0 &&
324 msqptr->msg_perm.key == key)
325 break;
326 }
327 if (msqid < msginfo.msgmni) {
328#ifdef MSG_DEBUG_OK
329 printf("found public key\n");
330#endif
331 if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) {
332#ifdef MSG_DEBUG_OK
333 printf("not exclusive\n");
334#endif
335 return(EEXIST);
336 }
337 if ((eval = ipcperm(cred, &msqptr->msg_perm, msgflg & 0700 ))) {
338#ifdef MSG_DEBUG_OK
339 printf("requester doesn't have 0%o access\n",
340 msgflg & 0700);
341#endif
342 return(eval);
343 }
344 goto found;
345 }
346 }
347
348#ifdef MSG_DEBUG_OK
349 printf("need to allocate the msqid_ds\n");
350#endif
351 if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) {
352 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
353 /*
354 * Look for an unallocated and unlocked msqid_ds.
355 * msqid_ds's can be locked by msgsnd or msgrcv while
356 * they are copying the message in/out. We can't
357 * re-use the entry until they release it.
358 */
359 msqptr = &msqids[msqid];
360 if (msqptr->msg_qbytes == 0 &&
361 (msqptr->msg_perm.mode & MSG_LOCKED) == 0)
362 break;
363 }
364 if (msqid == msginfo.msgmni) {
365#ifdef MSG_DEBUG_OK
366 printf("no more msqid_ds's available\n");
367#endif
368 return(ENOSPC);
369 }
370#ifdef MSG_DEBUG_OK
371 printf("msqid %d is available\n", msqid);
372#endif
373 msqptr->msg_perm.key = key;
374 msqptr->msg_perm.cuid = cred->cr_uid;
375 msqptr->msg_perm.uid = cred->cr_uid;
376 msqptr->msg_perm.cgid = cred->cr_gid;
377 msqptr->msg_perm.gid = cred->cr_gid;
378 msqptr->msg_perm.mode = (msgflg & 0777);
379 /* Make sure that the returned msqid is unique */
380 msqptr->msg_perm.seq++;
381 msqptr->msg_first = NULL;
382 msqptr->msg_last = NULL;
383 msqptr->msg_cbytes = 0;
384 msqptr->msg_qnum = 0;
385 msqptr->msg_qbytes = msginfo.msgmnb;
386 msqptr->msg_lspid = 0;
387 msqptr->msg_lrpid = 0;
388 msqptr->msg_stime = 0;
389 msqptr->msg_rtime = 0;
390 msqptr->msg_ctime = time.tv_sec;
391 } else {
392#ifdef MSG_DEBUG_OK
393 printf("didn't find it and wasn't asked to create it\n");
394#endif
395 return(ENOENT);
396 }
397
398found:
399 /* Construct the unique msqid */
400 *retval = IXSEQ_TO_IPCID(msqid, msqptr->msg_perm);
401 return(0);
402}
403
404struct msgsnd_args {
405 int msqid;
406 void *user_msgp;
407 size_t msgsz;
408 int msgflg;
409};
410
411static int
412msgsnd(p, uap, retval)
413 struct proc *p;
414 register struct msgsnd_args *uap;
415 int *retval;
416{
417 int msqid = uap->msqid;
418 void *user_msgp = uap->user_msgp;
419 size_t msgsz = uap->msgsz;
420 int msgflg = uap->msgflg;
421 int segs_needed, eval;
422 struct ucred *cred = p->p_ucred;
423 register struct msqid_ds *msqptr;
424 register struct msg *msghdr;
425 short next;
426
427#ifdef MSG_DEBUG_OK
428 printf("call to msgsnd(%d, 0x%x, %d, %d)\n", msqid, user_msgp, msgsz,
429 msgflg);
430#endif
431
432 msqid = IPCID_TO_IX(msqid);
433
434 if (msqid < 0 || msqid >= msginfo.msgmni) {
435#ifdef MSG_DEBUG_OK
436 printf("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
437 msginfo.msgmni);
438#endif
439 return(EINVAL);
440 }
441
442 msqptr = &msqids[msqid];
443 if (msqptr->msg_qbytes == 0) {
444#ifdef MSG_DEBUG_OK
445 printf("no such message queue id\n");
446#endif
447 return(EINVAL);
448 }
449 if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
450#ifdef MSG_DEBUG_OK
451 printf("wrong sequence number\n");
452#endif
453 return(EINVAL);
454 }
455
456 if ((eval = ipcperm(cred, &msqptr->msg_perm, IPC_W))) {
457#ifdef MSG_DEBUG_OK
458 printf("requester doesn't have write access\n");
459#endif
460 return(eval);
461 }
462
463 segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz;
464#ifdef MSG_DEBUG_OK
465 printf("msgsz=%d, msgssz=%d, segs_needed=%d\n", msgsz, msginfo.msgssz,
466 segs_needed);
467#endif
468 for (;;) {
469 int need_more_resources = 0;
470
471 /*
472 * check msgsz
473 * (inside this loop in case msg_qbytes changes while we sleep)
474 */
475
476 if (msgsz > msqptr->msg_qbytes) {
477#ifdef MSG_DEBUG_OK
478 printf("msgsz > msqptr->msg_qbytes\n");
479#endif
480 return(EINVAL);
481 }
482
483 if (msqptr->msg_perm.mode & MSG_LOCKED) {
484#ifdef MSG_DEBUG_OK
485 printf("msqid is locked\n");
486#endif
487 need_more_resources = 1;
488 }
489 if (msgsz + msqptr->msg_cbytes > msqptr->msg_qbytes) {
490#ifdef MSG_DEBUG_OK
491 printf("msgsz + msg_cbytes > msg_qbytes\n");
492#endif
493 need_more_resources = 1;
494 }
495 if (segs_needed > nfree_msgmaps) {
496#ifdef MSG_DEBUG_OK
497 printf("segs_needed > nfree_msgmaps\n");
498#endif
499 need_more_resources = 1;
500 }
501 if (free_msghdrs == NULL) {
502#ifdef MSG_DEBUG_OK
503 printf("no more msghdrs\n");
504#endif
505 need_more_resources = 1;
506 }
507
508 if (need_more_resources) {
509 int we_own_it;
510
511 if ((msgflg & IPC_NOWAIT) != 0) {
512#ifdef MSG_DEBUG_OK
513 printf("need more resources but caller doesn't want to wait\n");
514#endif
515 return(EAGAIN);
516 }
517
518 if ((msqptr->msg_perm.mode & MSG_LOCKED) != 0) {
519#ifdef MSG_DEBUG_OK
520 printf("we don't own the msqid_ds\n");
521#endif
522 we_own_it = 0;
523 } else {
524 /* Force later arrivals to wait for our
525 request */
526#ifdef MSG_DEBUG_OK
527 printf("we own the msqid_ds\n");
528#endif
529 msqptr->msg_perm.mode |= MSG_LOCKED;
530 we_own_it = 1;
531 }
532#ifdef MSG_DEBUG_OK
533 printf("goodnight\n");
534#endif
535 eval = tsleep((caddr_t)msqptr, (PZERO - 4) | PCATCH,
536 "msgwait", 0);
537#ifdef MSG_DEBUG_OK
538 printf("good morning, eval=%d\n", eval);
539#endif
540 if (we_own_it)
541 msqptr->msg_perm.mode &= ~MSG_LOCKED;
542 if (eval != 0) {
543#ifdef MSG_DEBUG_OK
544 printf("msgsnd: interrupted system call\n");
545#endif
546 return(EINTR);
547 }
548
549 /*
550 * Make sure that the msq queue still exists
551 */
552
553 if (msqptr->msg_qbytes == 0) {
554#ifdef MSG_DEBUG_OK
555 printf("msqid deleted\n");
556#endif
557 /* The SVID says to return EIDRM. */
558#ifdef EIDRM
559 return(EIDRM);
560#else
561 /* Unfortunately, BSD doesn't define that code
562 yet! */
563 return(EINVAL);
564#endif
565 }
566
567 } else {
568#ifdef MSG_DEBUG_OK
569 printf("got all the resources that we need\n");
570#endif
571 break;
572 }
573 }
574
575 /*
576 * We have the resources that we need.
577 * Make sure!
578 */
579
580 if (msqptr->msg_perm.mode & MSG_LOCKED)
581 panic("msg_perm.mode & MSG_LOCKED");
582 if (segs_needed > nfree_msgmaps)
583 panic("segs_needed > nfree_msgmaps");
584 if (msgsz + msqptr->msg_cbytes > msqptr->msg_qbytes)
585 panic("msgsz + msg_cbytes > msg_qbytes");
586 if (free_msghdrs == NULL)
587 panic("no more msghdrs");
588
589 /*
590 * Re-lock the msqid_ds in case we page-fault when copying in the
591 * message
592 */
593
594 if ((msqptr->msg_perm.mode & MSG_LOCKED) != 0)
595 panic("msqid_ds is already locked");
596 msqptr->msg_perm.mode |= MSG_LOCKED;
597
598 /*
599 * Allocate a message header
600 */
601
602 msghdr = free_msghdrs;
603 free_msghdrs = msghdr->msg_next;
604 msghdr->msg_spot = -1;
605 msghdr->msg_ts = msgsz;
606
607 /*
608 * Allocate space for the message
609 */
610
611 while (segs_needed > 0) {
612 if (nfree_msgmaps <= 0)
613 panic("not enough msgmaps");
614 if (free_msgmaps == -1)
615 panic("nil free_msgmaps");
616 next = free_msgmaps;
617 if (next <= -1)
618 panic("next too low #1");
619 if (next >= msginfo.msgseg)
620 panic("next out of range #1");
621#ifdef MSG_DEBUG_OK
622 printf("allocating segment %d to message\n", next);
623#endif
624 free_msgmaps = msgmaps[next].next;
625 nfree_msgmaps--;
626 msgmaps[next].next = msghdr->msg_spot;
627 msghdr->msg_spot = next;
628 segs_needed--;
629 }
630
631 /*
632 * Copy in the message type
633 */
634
635 if ((eval = copyin(user_msgp, &msghdr->msg_type,
636 sizeof(msghdr->msg_type))) != 0) {
637#ifdef MSG_DEBUG_OK
638 printf("error %d copying the message type\n", eval);
639#endif
640 msg_freehdr(msghdr);
641 msqptr->msg_perm.mode &= ~MSG_LOCKED;
642 wakeup((caddr_t)msqptr);
643 return(eval);
644 }
645 user_msgp += sizeof(msghdr->msg_type);
646
647 /*
648 * Validate the message type
649 */
650
651 if (msghdr->msg_type < 1) {
652 msg_freehdr(msghdr);
653 msqptr->msg_perm.mode &= ~MSG_LOCKED;
654 wakeup((caddr_t)msqptr);
655#ifdef MSG_DEBUG_OK
656 printf("mtype (%d) < 1\n", msghdr->msg_type);
657#endif
658 return(EINVAL);
659 }
660
661 /*
662 * Copy in the message body
663 */
664
665 next = msghdr->msg_spot;
666 while (msgsz > 0) {
667 size_t tlen;
668 if (msgsz > msginfo.msgssz)
669 tlen = msginfo.msgssz;
670 else
671 tlen = msgsz;
672 if (next <= -1)
673 panic("next too low #2");
674 if (next >= msginfo.msgseg)
675 panic("next out of range #2");
676 if ((eval = copyin(user_msgp, &msgpool[next * msginfo.msgssz],
677 tlen)) != 0) {
678#ifdef MSG_DEBUG_OK
679 printf("error %d copying in message segment\n", eval);
680#endif
681 msg_freehdr(msghdr);
682 msqptr->msg_perm.mode &= ~MSG_LOCKED;
683 wakeup((caddr_t)msqptr);
684 return(eval);
685 }
686 msgsz -= tlen;
687 user_msgp += tlen;
688 next = msgmaps[next].next;
689 }
690 if (next != -1)
691 panic("didn't use all the msg segments");
692
693 /*
694 * We've got the message. Unlock the msqid_ds.
695 */
696
697 msqptr->msg_perm.mode &= ~MSG_LOCKED;
698
699 /*
700 * Make sure that the msqid_ds is still allocated.
701 */
702
703 if (msqptr->msg_qbytes == 0) {
704 msg_freehdr(msghdr);
705 wakeup((caddr_t)msqptr);
706 /* The SVID says to return EIDRM. */
707#ifdef EIDRM
708 return(EIDRM);
709#else
710 /* Unfortunately, BSD doesn't define that code yet! */
711 return(EINVAL);
712#endif
713 }
714
715 /*
716 * Put the message into the queue
717 */
718
719 if (msqptr->msg_first == NULL) {
720 msqptr->msg_first = msghdr;
721 msqptr->msg_last = msghdr;
722 } else {
723 msqptr->msg_last->msg_next = msghdr;
724 msqptr->msg_last = msghdr;
725 }
726 msqptr->msg_last->msg_next = NULL;
727
728 msqptr->msg_cbytes += msghdr->msg_ts;
729 msqptr->msg_qnum++;
730 msqptr->msg_lspid = p->p_pid;
731 msqptr->msg_stime = time.tv_sec;
732
733 wakeup((caddr_t)msqptr);
734 *retval = 0;
735 return(0);
736}
737
738struct msgrcv_args {
739 int msqid;
740 void *msgp;
741 size_t msgsz;
742 long msgtyp;
743 int msgflg;
744};
745
746static int
747msgrcv(p, uap, retval)
748 struct proc *p;
749 register struct msgrcv_args *uap;
750 int *retval;
751{
752 int msqid = uap->msqid;
753 void *user_msgp = uap->msgp;
754 size_t msgsz = uap->msgsz;
755 long msgtyp = uap->msgtyp;
756 int msgflg = uap->msgflg;
757 size_t len;
758 struct ucred *cred = p->p_ucred;
759 register struct msqid_ds *msqptr;
760 register struct msg *msghdr;
761 int eval;
762 short next;
763
764#ifdef MSG_DEBUG_OK
765 printf("call to msgrcv(%d, 0x%x, %d, %ld, %d)\n", msqid, user_msgp,
766 msgsz, msgtyp, msgflg);
767#endif
768
769 msqid = IPCID_TO_IX(msqid);
770
771 if (msqid < 0 || msqid >= msginfo.msgmni) {
772#ifdef MSG_DEBUG_OK
773 printf("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
774 msginfo.msgmni);
775#endif
776 return(EINVAL);
777 }
778
779 msqptr = &msqids[msqid];
780 if (msqptr->msg_qbytes == 0) {
781#ifdef MSG_DEBUG_OK
782 printf("no such message queue id\n");
783#endif
784 return(EINVAL);
785 }
786 if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
787#ifdef MSG_DEBUG_OK
788 printf("wrong sequence number\n");
789#endif
790 return(EINVAL);
791 }
792
793 if ((eval = ipcperm(cred, &msqptr->msg_perm, IPC_R))) {
794#ifdef MSG_DEBUG_OK
795 printf("requester doesn't have read access\n");
796#endif
797 return(eval);
798 }
799
800 msghdr = NULL;
801 while (msghdr == NULL) {
802 if (msgtyp == 0) {
803 msghdr = msqptr->msg_first;
804 if (msghdr != NULL) {
805 if (msgsz < msghdr->msg_ts &&
806 (msgflg & MSG_NOERROR) == 0) {
807#ifdef MSG_DEBUG_OK
808 printf("first message on the queue is too big (want %d, got %d)\n",
809 msgsz, msghdr->msg_ts);
810#endif
811 return(E2BIG);
812 }
813 if (msqptr->msg_first == msqptr->msg_last) {
814 msqptr->msg_first = NULL;
815 msqptr->msg_last = NULL;
816 } else {
817 msqptr->msg_first = msghdr->msg_next;
818 if (msqptr->msg_first == NULL)
819 panic("msg_first/last screwed up #1");
820 }
821 }
822 } else {
823 struct msg *previous;
824 struct msg **prev;
825
826 previous = NULL;
827 prev = &(msqptr->msg_first);
828 while ((msghdr = *prev) != NULL) {
829 /*
830 * Is this message's type an exact match or is
831 * this message's type less than or equal to
832 * the absolute value of a negative msgtyp?
833 * Note that the second half of this test can
834 * NEVER be true if msgtyp is positive since
835 * msg_type is always positive!
836 */
837
838 if (msgtyp == msghdr->msg_type ||
839 msghdr->msg_type <= -msgtyp) {
840#ifdef MSG_DEBUG_OK
841 printf("found message type %d, requested %d\n",
842 msghdr->msg_type, msgtyp);
843#endif
844 if (msgsz < msghdr->msg_ts &&
845 (msgflg & MSG_NOERROR) == 0) {
846#ifdef MSG_DEBUG_OK
847 printf("requested message on the queue is too big (want %d, got %d)\n",
848 msgsz, msghdr->msg_ts);
849#endif
850 return(E2BIG);
851 }
852 *prev = msghdr->msg_next;
853 if (msghdr == msqptr->msg_last) {
854 if (previous == NULL) {
855 if (prev !=
856 &msqptr->msg_first)
857 panic("msg_first/last screwed up #2");
858 msqptr->msg_first =
859 NULL;
860 msqptr->msg_last =
861 NULL;
862 } else {
863 if (prev ==
864 &msqptr->msg_first)
865 panic("msg_first/last screwed up #3");
866 msqptr->msg_last =
867 previous;
868 }
869 }
870 break;
871 }
872 previous = msghdr;
873 prev = &(msghdr->msg_next);
874 }
875 }
876
877 /*
878 * We've either extracted the msghdr for the appropriate
879 * message or there isn't one.
880 * If there is one then bail out of this loop.
881 */
882
883 if (msghdr != NULL)
884 break;
885
886 /*
887 * Hmph! No message found. Does the user want to wait?
888 */
889
890 if ((msgflg & IPC_NOWAIT) != 0) {
891#ifdef MSG_DEBUG_OK
892 printf("no appropriate message found (msgtyp=%d)\n",
893 msgtyp);
894#endif
895 /* The SVID says to return ENOMSG. */
896#ifdef ENOMSG
897 return(ENOMSG);
898#else
899 /* Unfortunately, BSD doesn't define that code yet! */
900 return(EAGAIN);
901#endif
902 }
903
904 /*
905 * Wait for something to happen
906 */
907
908#ifdef MSG_DEBUG_OK
909 printf("msgrcv: goodnight\n");
910#endif
911 eval = tsleep((caddr_t)msqptr, (PZERO - 4) | PCATCH, "msgwait",
912 0);
913#ifdef MSG_DEBUG_OK
914 printf("msgrcv: good morning (eval=%d)\n", eval);
915#endif
916
917 if (eval != 0) {
918#ifdef MSG_DEBUG_OK
919 printf("msgsnd: interrupted system call\n");
920#endif
921 return(EINTR);
922 }
923
924 /*
925 * Make sure that the msq queue still exists
926 */
927
928 if (msqptr->msg_qbytes == 0 ||
929 msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
930#ifdef MSG_DEBUG_OK
931 printf("msqid deleted\n");
932#endif
933 /* The SVID says to return EIDRM. */
934#ifdef EIDRM
935 return(EIDRM);
936#else
937 /* Unfortunately, BSD doesn't define that code yet! */
938 return(EINVAL);
939#endif
940 }
941 }
942
943 /*
944 * Return the message to the user.
945 *
946 * First, do the bookkeeping (before we risk being interrupted).
947 */
948
949 msqptr->msg_cbytes -= msghdr->msg_ts;
950 msqptr->msg_qnum--;
951 msqptr->msg_lrpid = p->p_pid;
952 msqptr->msg_rtime = time.tv_sec;
953
954 /*
955 * Make msgsz the actual amount that we'll be returning.
956 * Note that this effectively truncates the message if it is too long
957 * (since msgsz is never increased).
958 */
959
960#ifdef MSG_DEBUG_OK
961 printf("found a message, msgsz=%d, msg_ts=%d\n", msgsz,
962 msghdr->msg_ts);
963#endif
964 if (msgsz > msghdr->msg_ts)
965 msgsz = msghdr->msg_ts;
966
967 /*
968 * Return the type to the user.
969 */
970
971 eval = copyout((caddr_t)&(msghdr->msg_type), user_msgp,
972 sizeof(msghdr->msg_type));
973 if (eval != 0) {
974#ifdef MSG_DEBUG_OK
975 printf("error (%d) copying out message type\n", eval);
976#endif
977 msg_freehdr(msghdr);
978 wakeup((caddr_t)msqptr);
979 return(eval);
980 }
981 user_msgp += sizeof(msghdr->msg_type);
982
983 /*
984 * Return the segments to the user
985 */
986
987 next = msghdr->msg_spot;
988 for (len = 0; len < msgsz; len += msginfo.msgssz) {
989 size_t tlen;
990
991 if (msgsz > msginfo.msgssz)
992 tlen = msginfo.msgssz;
993 else
994 tlen = msgsz;
995 if (next <= -1)
996 panic("next too low #3");
997 if (next >= msginfo.msgseg)
998 panic("next out of range #3");
999 eval = copyout((caddr_t)&msgpool[next * msginfo.msgssz],
1000 user_msgp, tlen);
1001 if (eval != 0) {
1002#ifdef MSG_DEBUG_OK
1003 printf("error (%d) copying out message segment\n",
1004 eval);
1005#endif
1006 msg_freehdr(msghdr);
1007 wakeup((caddr_t)msqptr);
1008 return(eval);
1009 }
1010 user_msgp += tlen;
1011 next = msgmaps[next].next;
1012 }
1013
1014 /*
1015 * Done, return the actual number of bytes copied out.
1016 */
1017
1018 msg_freehdr(msghdr);
1019 wakeup((caddr_t)msqptr);
1020 *retval = msgsz;
1021 return(0);
1022}
55char *msgpool; /* MSGMAX byte long msg buffer pool */
56struct msgmap *msgmaps; /* MSGSEG msgmap structures */
57struct msg *msghdrs; /* MSGTQL msg headers */
58struct msqid_ds *msqids; /* MSGMNI msqid_ds struct's */
59
60void
61msginit(dummy)
62 void *dummy;
63{
64 register int i;
65
66 /*
67 * msginfo.msgssz should be a power of two for efficiency reasons.
68 * It is also pretty silly if msginfo.msgssz is less than 8
69 * or greater than about 256 so ...
70 */
71
72 i = 8;
73 while (i < 1024 && i != msginfo.msgssz)
74 i <<= 1;
75 if (i != msginfo.msgssz) {
76 printf("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz,
77 msginfo.msgssz);
78 panic("msginfo.msgssz not a small power of 2");
79 }
80
81 if (msginfo.msgseg > 32767) {
82 printf("msginfo.msgseg=%d\n", msginfo.msgseg);
83 panic("msginfo.msgseg > 32767");
84 }
85
86 if (msgmaps == NULL)
87 panic("msgmaps is NULL");
88
89 for (i = 0; i < msginfo.msgseg; i++) {
90 if (i > 0)
91 msgmaps[i-1].next = i;
92 msgmaps[i].next = -1; /* implies entry is available */
93 }
94 free_msgmaps = 0;
95 nfree_msgmaps = msginfo.msgseg;
96
97 if (msghdrs == NULL)
98 panic("msghdrs is NULL");
99
100 for (i = 0; i < msginfo.msgtql; i++) {
101 msghdrs[i].msg_type = 0;
102 if (i > 0)
103 msghdrs[i-1].msg_next = &msghdrs[i];
104 msghdrs[i].msg_next = NULL;
105 }
106 free_msghdrs = &msghdrs[0];
107
108 if (msqids == NULL)
109 panic("msqids is NULL");
110
111 for (i = 0; i < msginfo.msgmni; i++) {
112 msqids[i].msg_qbytes = 0; /* implies entry is available */
113 msqids[i].msg_perm.seq = 0; /* reset to a known value */
114 }
115}
116
117/*
118 * Entry point for all MSG calls
119 */
120int
121msgsys(p, uap, retval)
122 struct proc *p;
123 /* XXX actually varargs. */
124 struct msgsys_args /* {
125 u_int which;
126 int a2;
127 int a3;
128 int a4;
129 int a5;
130 int a6;
131 } */ *uap;
132 int *retval;
133{
134
135 if (uap->which >= sizeof(msgcalls)/sizeof(msgcalls[0]))
136 return (EINVAL);
137 return ((*msgcalls[uap->which])(p, &uap->a2, retval));
138}
139
140static void
141msg_freehdr(msghdr)
142 struct msg *msghdr;
143{
144 while (msghdr->msg_ts > 0) {
145 short next;
146 if (msghdr->msg_spot < 0 || msghdr->msg_spot >= msginfo.msgseg)
147 panic("msghdr->msg_spot out of range");
148 next = msgmaps[msghdr->msg_spot].next;
149 msgmaps[msghdr->msg_spot].next = free_msgmaps;
150 free_msgmaps = msghdr->msg_spot;
151 nfree_msgmaps++;
152 msghdr->msg_spot = next;
153 if (msghdr->msg_ts >= msginfo.msgssz)
154 msghdr->msg_ts -= msginfo.msgssz;
155 else
156 msghdr->msg_ts = 0;
157 }
158 if (msghdr->msg_spot != -1)
159 panic("msghdr->msg_spot != -1");
160 msghdr->msg_next = free_msghdrs;
161 free_msghdrs = msghdr;
162}
163
164struct msgctl_args {
165 int msqid;
166 int cmd;
167 struct msqid_ds *user_msqptr;
168};
169
170static int
171msgctl(p, uap, retval)
172 struct proc *p;
173 register struct msgctl_args *uap;
174 int *retval;
175{
176 int msqid = uap->msqid;
177 int cmd = uap->cmd;
178 struct msqid_ds *user_msqptr = uap->user_msqptr;
179 struct ucred *cred = p->p_ucred;
180 int rval, eval;
181 struct msqid_ds msqbuf;
182 register struct msqid_ds *msqptr;
183
184#ifdef MSG_DEBUG_OK
185 printf("call to msgctl(%d, %d, 0x%x)\n", msqid, cmd, user_msqptr);
186#endif
187
188 msqid = IPCID_TO_IX(msqid);
189
190 if (msqid < 0 || msqid >= msginfo.msgmni) {
191#ifdef MSG_DEBUG_OK
192 printf("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
193 msginfo.msgmni);
194#endif
195 return(EINVAL);
196 }
197
198 msqptr = &msqids[msqid];
199
200 if (msqptr->msg_qbytes == 0) {
201#ifdef MSG_DEBUG_OK
202 printf("no such msqid\n");
203#endif
204 return(EINVAL);
205 }
206 if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
207#ifdef MSG_DEBUG_OK
208 printf("wrong sequence number\n");
209#endif
210 return(EINVAL);
211 }
212
213 eval = 0;
214 rval = 0;
215
216 switch (cmd) {
217
218 case IPC_RMID:
219 {
220 struct msg *msghdr;
221 if ((eval = ipcperm(cred, &msqptr->msg_perm, IPC_M)))
222 return(eval);
223 /* Free the message headers */
224 msghdr = msqptr->msg_first;
225 while (msghdr != NULL) {
226 struct msg *msghdr_tmp;
227
228 /* Free the segments of each message */
229 msqptr->msg_cbytes -= msghdr->msg_ts;
230 msqptr->msg_qnum--;
231 msghdr_tmp = msghdr;
232 msghdr = msghdr->msg_next;
233 msg_freehdr(msghdr_tmp);
234 }
235
236 if (msqptr->msg_cbytes != 0)
237 panic("msg_cbytes is screwed up");
238 if (msqptr->msg_qnum != 0)
239 panic("msg_qnum is screwed up");
240
241 msqptr->msg_qbytes = 0; /* Mark it as free */
242
243 wakeup((caddr_t)msqptr);
244 }
245
246 break;
247
248 case IPC_SET:
249 if ((eval = ipcperm(cred, &msqptr->msg_perm, IPC_M)))
250 return(eval);
251 if ((eval = copyin(user_msqptr, &msqbuf, sizeof(msqbuf))) != 0)
252 return(eval);
253 if (msqbuf.msg_qbytes > msqptr->msg_qbytes && cred->cr_uid != 0)
254 return(EPERM);
255 if (msqbuf.msg_qbytes > msginfo.msgmnb) {
256#ifdef MSG_DEBUG_OK
257 printf("can't increase msg_qbytes beyond %d (truncating)\n",
258 msginfo.msgmnb);
259#endif
260 msqbuf.msg_qbytes = msginfo.msgmnb; /* silently restrict qbytes to system limit */
261 }
262 if (msqbuf.msg_qbytes == 0) {
263#ifdef MSG_DEBUG_OK
264 printf("can't reduce msg_qbytes to 0\n");
265#endif
266 return(EINVAL); /* non-standard errno! */
267 }
268 msqptr->msg_perm.uid = msqbuf.msg_perm.uid; /* change the owner */
269 msqptr->msg_perm.gid = msqbuf.msg_perm.gid; /* change the owner */
270 msqptr->msg_perm.mode = (msqptr->msg_perm.mode & ~0777) |
271 (msqbuf.msg_perm.mode & 0777);
272 msqptr->msg_qbytes = msqbuf.msg_qbytes;
273 msqptr->msg_ctime = time.tv_sec;
274 break;
275
276 case IPC_STAT:
277 if ((eval = ipcperm(cred, &msqptr->msg_perm, IPC_R))) {
278#ifdef MSG_DEBUG_OK
279 printf("requester doesn't have read access\n");
280#endif
281 return(eval);
282 }
283 eval = copyout((caddr_t)msqptr, user_msqptr,
284 sizeof(struct msqid_ds));
285 break;
286
287 default:
288#ifdef MSG_DEBUG_OK
289 printf("invalid command %d\n", cmd);
290#endif
291 return(EINVAL);
292 }
293
294 if (eval == 0)
295 *retval = rval;
296 return(eval);
297}
298
299struct msgget_args {
300 key_t key;
301 int msgflg;
302};
303
304static int
305msgget(p, uap, retval)
306 struct proc *p;
307 register struct msgget_args *uap;
308 int *retval;
309{
310 int msqid, eval;
311 int key = uap->key;
312 int msgflg = uap->msgflg;
313 struct ucred *cred = p->p_ucred;
314 register struct msqid_ds *msqptr = NULL;
315
316#ifdef MSG_DEBUG_OK
317 printf("msgget(0x%x, 0%o)\n", key, msgflg);
318#endif
319
320 if (key != IPC_PRIVATE) {
321 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
322 msqptr = &msqids[msqid];
323 if (msqptr->msg_qbytes != 0 &&
324 msqptr->msg_perm.key == key)
325 break;
326 }
327 if (msqid < msginfo.msgmni) {
328#ifdef MSG_DEBUG_OK
329 printf("found public key\n");
330#endif
331 if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) {
332#ifdef MSG_DEBUG_OK
333 printf("not exclusive\n");
334#endif
335 return(EEXIST);
336 }
337 if ((eval = ipcperm(cred, &msqptr->msg_perm, msgflg & 0700 ))) {
338#ifdef MSG_DEBUG_OK
339 printf("requester doesn't have 0%o access\n",
340 msgflg & 0700);
341#endif
342 return(eval);
343 }
344 goto found;
345 }
346 }
347
348#ifdef MSG_DEBUG_OK
349 printf("need to allocate the msqid_ds\n");
350#endif
351 if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) {
352 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
353 /*
354 * Look for an unallocated and unlocked msqid_ds.
355 * msqid_ds's can be locked by msgsnd or msgrcv while
356 * they are copying the message in/out. We can't
357 * re-use the entry until they release it.
358 */
359 msqptr = &msqids[msqid];
360 if (msqptr->msg_qbytes == 0 &&
361 (msqptr->msg_perm.mode & MSG_LOCKED) == 0)
362 break;
363 }
364 if (msqid == msginfo.msgmni) {
365#ifdef MSG_DEBUG_OK
366 printf("no more msqid_ds's available\n");
367#endif
368 return(ENOSPC);
369 }
370#ifdef MSG_DEBUG_OK
371 printf("msqid %d is available\n", msqid);
372#endif
373 msqptr->msg_perm.key = key;
374 msqptr->msg_perm.cuid = cred->cr_uid;
375 msqptr->msg_perm.uid = cred->cr_uid;
376 msqptr->msg_perm.cgid = cred->cr_gid;
377 msqptr->msg_perm.gid = cred->cr_gid;
378 msqptr->msg_perm.mode = (msgflg & 0777);
379 /* Make sure that the returned msqid is unique */
380 msqptr->msg_perm.seq++;
381 msqptr->msg_first = NULL;
382 msqptr->msg_last = NULL;
383 msqptr->msg_cbytes = 0;
384 msqptr->msg_qnum = 0;
385 msqptr->msg_qbytes = msginfo.msgmnb;
386 msqptr->msg_lspid = 0;
387 msqptr->msg_lrpid = 0;
388 msqptr->msg_stime = 0;
389 msqptr->msg_rtime = 0;
390 msqptr->msg_ctime = time.tv_sec;
391 } else {
392#ifdef MSG_DEBUG_OK
393 printf("didn't find it and wasn't asked to create it\n");
394#endif
395 return(ENOENT);
396 }
397
398found:
399 /* Construct the unique msqid */
400 *retval = IXSEQ_TO_IPCID(msqid, msqptr->msg_perm);
401 return(0);
402}
403
404struct msgsnd_args {
405 int msqid;
406 void *user_msgp;
407 size_t msgsz;
408 int msgflg;
409};
410
411static int
412msgsnd(p, uap, retval)
413 struct proc *p;
414 register struct msgsnd_args *uap;
415 int *retval;
416{
417 int msqid = uap->msqid;
418 void *user_msgp = uap->user_msgp;
419 size_t msgsz = uap->msgsz;
420 int msgflg = uap->msgflg;
421 int segs_needed, eval;
422 struct ucred *cred = p->p_ucred;
423 register struct msqid_ds *msqptr;
424 register struct msg *msghdr;
425 short next;
426
427#ifdef MSG_DEBUG_OK
428 printf("call to msgsnd(%d, 0x%x, %d, %d)\n", msqid, user_msgp, msgsz,
429 msgflg);
430#endif
431
432 msqid = IPCID_TO_IX(msqid);
433
434 if (msqid < 0 || msqid >= msginfo.msgmni) {
435#ifdef MSG_DEBUG_OK
436 printf("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
437 msginfo.msgmni);
438#endif
439 return(EINVAL);
440 }
441
442 msqptr = &msqids[msqid];
443 if (msqptr->msg_qbytes == 0) {
444#ifdef MSG_DEBUG_OK
445 printf("no such message queue id\n");
446#endif
447 return(EINVAL);
448 }
449 if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
450#ifdef MSG_DEBUG_OK
451 printf("wrong sequence number\n");
452#endif
453 return(EINVAL);
454 }
455
456 if ((eval = ipcperm(cred, &msqptr->msg_perm, IPC_W))) {
457#ifdef MSG_DEBUG_OK
458 printf("requester doesn't have write access\n");
459#endif
460 return(eval);
461 }
462
463 segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz;
464#ifdef MSG_DEBUG_OK
465 printf("msgsz=%d, msgssz=%d, segs_needed=%d\n", msgsz, msginfo.msgssz,
466 segs_needed);
467#endif
468 for (;;) {
469 int need_more_resources = 0;
470
471 /*
472 * check msgsz
473 * (inside this loop in case msg_qbytes changes while we sleep)
474 */
475
476 if (msgsz > msqptr->msg_qbytes) {
477#ifdef MSG_DEBUG_OK
478 printf("msgsz > msqptr->msg_qbytes\n");
479#endif
480 return(EINVAL);
481 }
482
483 if (msqptr->msg_perm.mode & MSG_LOCKED) {
484#ifdef MSG_DEBUG_OK
485 printf("msqid is locked\n");
486#endif
487 need_more_resources = 1;
488 }
489 if (msgsz + msqptr->msg_cbytes > msqptr->msg_qbytes) {
490#ifdef MSG_DEBUG_OK
491 printf("msgsz + msg_cbytes > msg_qbytes\n");
492#endif
493 need_more_resources = 1;
494 }
495 if (segs_needed > nfree_msgmaps) {
496#ifdef MSG_DEBUG_OK
497 printf("segs_needed > nfree_msgmaps\n");
498#endif
499 need_more_resources = 1;
500 }
501 if (free_msghdrs == NULL) {
502#ifdef MSG_DEBUG_OK
503 printf("no more msghdrs\n");
504#endif
505 need_more_resources = 1;
506 }
507
508 if (need_more_resources) {
509 int we_own_it;
510
511 if ((msgflg & IPC_NOWAIT) != 0) {
512#ifdef MSG_DEBUG_OK
513 printf("need more resources but caller doesn't want to wait\n");
514#endif
515 return(EAGAIN);
516 }
517
518 if ((msqptr->msg_perm.mode & MSG_LOCKED) != 0) {
519#ifdef MSG_DEBUG_OK
520 printf("we don't own the msqid_ds\n");
521#endif
522 we_own_it = 0;
523 } else {
524 /* Force later arrivals to wait for our
525 request */
526#ifdef MSG_DEBUG_OK
527 printf("we own the msqid_ds\n");
528#endif
529 msqptr->msg_perm.mode |= MSG_LOCKED;
530 we_own_it = 1;
531 }
532#ifdef MSG_DEBUG_OK
533 printf("goodnight\n");
534#endif
535 eval = tsleep((caddr_t)msqptr, (PZERO - 4) | PCATCH,
536 "msgwait", 0);
537#ifdef MSG_DEBUG_OK
538 printf("good morning, eval=%d\n", eval);
539#endif
540 if (we_own_it)
541 msqptr->msg_perm.mode &= ~MSG_LOCKED;
542 if (eval != 0) {
543#ifdef MSG_DEBUG_OK
544 printf("msgsnd: interrupted system call\n");
545#endif
546 return(EINTR);
547 }
548
549 /*
550 * Make sure that the msq queue still exists
551 */
552
553 if (msqptr->msg_qbytes == 0) {
554#ifdef MSG_DEBUG_OK
555 printf("msqid deleted\n");
556#endif
557 /* The SVID says to return EIDRM. */
558#ifdef EIDRM
559 return(EIDRM);
560#else
561 /* Unfortunately, BSD doesn't define that code
562 yet! */
563 return(EINVAL);
564#endif
565 }
566
567 } else {
568#ifdef MSG_DEBUG_OK
569 printf("got all the resources that we need\n");
570#endif
571 break;
572 }
573 }
574
575 /*
576 * We have the resources that we need.
577 * Make sure!
578 */
579
580 if (msqptr->msg_perm.mode & MSG_LOCKED)
581 panic("msg_perm.mode & MSG_LOCKED");
582 if (segs_needed > nfree_msgmaps)
583 panic("segs_needed > nfree_msgmaps");
584 if (msgsz + msqptr->msg_cbytes > msqptr->msg_qbytes)
585 panic("msgsz + msg_cbytes > msg_qbytes");
586 if (free_msghdrs == NULL)
587 panic("no more msghdrs");
588
589 /*
590 * Re-lock the msqid_ds in case we page-fault when copying in the
591 * message
592 */
593
594 if ((msqptr->msg_perm.mode & MSG_LOCKED) != 0)
595 panic("msqid_ds is already locked");
596 msqptr->msg_perm.mode |= MSG_LOCKED;
597
598 /*
599 * Allocate a message header
600 */
601
602 msghdr = free_msghdrs;
603 free_msghdrs = msghdr->msg_next;
604 msghdr->msg_spot = -1;
605 msghdr->msg_ts = msgsz;
606
607 /*
608 * Allocate space for the message
609 */
610
611 while (segs_needed > 0) {
612 if (nfree_msgmaps <= 0)
613 panic("not enough msgmaps");
614 if (free_msgmaps == -1)
615 panic("nil free_msgmaps");
616 next = free_msgmaps;
617 if (next <= -1)
618 panic("next too low #1");
619 if (next >= msginfo.msgseg)
620 panic("next out of range #1");
621#ifdef MSG_DEBUG_OK
622 printf("allocating segment %d to message\n", next);
623#endif
624 free_msgmaps = msgmaps[next].next;
625 nfree_msgmaps--;
626 msgmaps[next].next = msghdr->msg_spot;
627 msghdr->msg_spot = next;
628 segs_needed--;
629 }
630
631 /*
632 * Copy in the message type
633 */
634
635 if ((eval = copyin(user_msgp, &msghdr->msg_type,
636 sizeof(msghdr->msg_type))) != 0) {
637#ifdef MSG_DEBUG_OK
638 printf("error %d copying the message type\n", eval);
639#endif
640 msg_freehdr(msghdr);
641 msqptr->msg_perm.mode &= ~MSG_LOCKED;
642 wakeup((caddr_t)msqptr);
643 return(eval);
644 }
645 user_msgp += sizeof(msghdr->msg_type);
646
647 /*
648 * Validate the message type
649 */
650
651 if (msghdr->msg_type < 1) {
652 msg_freehdr(msghdr);
653 msqptr->msg_perm.mode &= ~MSG_LOCKED;
654 wakeup((caddr_t)msqptr);
655#ifdef MSG_DEBUG_OK
656 printf("mtype (%d) < 1\n", msghdr->msg_type);
657#endif
658 return(EINVAL);
659 }
660
661 /*
662 * Copy in the message body
663 */
664
665 next = msghdr->msg_spot;
666 while (msgsz > 0) {
667 size_t tlen;
668 if (msgsz > msginfo.msgssz)
669 tlen = msginfo.msgssz;
670 else
671 tlen = msgsz;
672 if (next <= -1)
673 panic("next too low #2");
674 if (next >= msginfo.msgseg)
675 panic("next out of range #2");
676 if ((eval = copyin(user_msgp, &msgpool[next * msginfo.msgssz],
677 tlen)) != 0) {
678#ifdef MSG_DEBUG_OK
679 printf("error %d copying in message segment\n", eval);
680#endif
681 msg_freehdr(msghdr);
682 msqptr->msg_perm.mode &= ~MSG_LOCKED;
683 wakeup((caddr_t)msqptr);
684 return(eval);
685 }
686 msgsz -= tlen;
687 user_msgp += tlen;
688 next = msgmaps[next].next;
689 }
690 if (next != -1)
691 panic("didn't use all the msg segments");
692
693 /*
694 * We've got the message. Unlock the msqid_ds.
695 */
696
697 msqptr->msg_perm.mode &= ~MSG_LOCKED;
698
699 /*
700 * Make sure that the msqid_ds is still allocated.
701 */
702
703 if (msqptr->msg_qbytes == 0) {
704 msg_freehdr(msghdr);
705 wakeup((caddr_t)msqptr);
706 /* The SVID says to return EIDRM. */
707#ifdef EIDRM
708 return(EIDRM);
709#else
710 /* Unfortunately, BSD doesn't define that code yet! */
711 return(EINVAL);
712#endif
713 }
714
715 /*
716 * Put the message into the queue
717 */
718
719 if (msqptr->msg_first == NULL) {
720 msqptr->msg_first = msghdr;
721 msqptr->msg_last = msghdr;
722 } else {
723 msqptr->msg_last->msg_next = msghdr;
724 msqptr->msg_last = msghdr;
725 }
726 msqptr->msg_last->msg_next = NULL;
727
728 msqptr->msg_cbytes += msghdr->msg_ts;
729 msqptr->msg_qnum++;
730 msqptr->msg_lspid = p->p_pid;
731 msqptr->msg_stime = time.tv_sec;
732
733 wakeup((caddr_t)msqptr);
734 *retval = 0;
735 return(0);
736}
737
738struct msgrcv_args {
739 int msqid;
740 void *msgp;
741 size_t msgsz;
742 long msgtyp;
743 int msgflg;
744};
745
746static int
747msgrcv(p, uap, retval)
748 struct proc *p;
749 register struct msgrcv_args *uap;
750 int *retval;
751{
752 int msqid = uap->msqid;
753 void *user_msgp = uap->msgp;
754 size_t msgsz = uap->msgsz;
755 long msgtyp = uap->msgtyp;
756 int msgflg = uap->msgflg;
757 size_t len;
758 struct ucred *cred = p->p_ucred;
759 register struct msqid_ds *msqptr;
760 register struct msg *msghdr;
761 int eval;
762 short next;
763
764#ifdef MSG_DEBUG_OK
765 printf("call to msgrcv(%d, 0x%x, %d, %ld, %d)\n", msqid, user_msgp,
766 msgsz, msgtyp, msgflg);
767#endif
768
769 msqid = IPCID_TO_IX(msqid);
770
771 if (msqid < 0 || msqid >= msginfo.msgmni) {
772#ifdef MSG_DEBUG_OK
773 printf("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
774 msginfo.msgmni);
775#endif
776 return(EINVAL);
777 }
778
779 msqptr = &msqids[msqid];
780 if (msqptr->msg_qbytes == 0) {
781#ifdef MSG_DEBUG_OK
782 printf("no such message queue id\n");
783#endif
784 return(EINVAL);
785 }
786 if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
787#ifdef MSG_DEBUG_OK
788 printf("wrong sequence number\n");
789#endif
790 return(EINVAL);
791 }
792
793 if ((eval = ipcperm(cred, &msqptr->msg_perm, IPC_R))) {
794#ifdef MSG_DEBUG_OK
795 printf("requester doesn't have read access\n");
796#endif
797 return(eval);
798 }
799
800 msghdr = NULL;
801 while (msghdr == NULL) {
802 if (msgtyp == 0) {
803 msghdr = msqptr->msg_first;
804 if (msghdr != NULL) {
805 if (msgsz < msghdr->msg_ts &&
806 (msgflg & MSG_NOERROR) == 0) {
807#ifdef MSG_DEBUG_OK
808 printf("first message on the queue is too big (want %d, got %d)\n",
809 msgsz, msghdr->msg_ts);
810#endif
811 return(E2BIG);
812 }
813 if (msqptr->msg_first == msqptr->msg_last) {
814 msqptr->msg_first = NULL;
815 msqptr->msg_last = NULL;
816 } else {
817 msqptr->msg_first = msghdr->msg_next;
818 if (msqptr->msg_first == NULL)
819 panic("msg_first/last screwed up #1");
820 }
821 }
822 } else {
823 struct msg *previous;
824 struct msg **prev;
825
826 previous = NULL;
827 prev = &(msqptr->msg_first);
828 while ((msghdr = *prev) != NULL) {
829 /*
830 * Is this message's type an exact match or is
831 * this message's type less than or equal to
832 * the absolute value of a negative msgtyp?
833 * Note that the second half of this test can
834 * NEVER be true if msgtyp is positive since
835 * msg_type is always positive!
836 */
837
838 if (msgtyp == msghdr->msg_type ||
839 msghdr->msg_type <= -msgtyp) {
840#ifdef MSG_DEBUG_OK
841 printf("found message type %d, requested %d\n",
842 msghdr->msg_type, msgtyp);
843#endif
844 if (msgsz < msghdr->msg_ts &&
845 (msgflg & MSG_NOERROR) == 0) {
846#ifdef MSG_DEBUG_OK
847 printf("requested message on the queue is too big (want %d, got %d)\n",
848 msgsz, msghdr->msg_ts);
849#endif
850 return(E2BIG);
851 }
852 *prev = msghdr->msg_next;
853 if (msghdr == msqptr->msg_last) {
854 if (previous == NULL) {
855 if (prev !=
856 &msqptr->msg_first)
857 panic("msg_first/last screwed up #2");
858 msqptr->msg_first =
859 NULL;
860 msqptr->msg_last =
861 NULL;
862 } else {
863 if (prev ==
864 &msqptr->msg_first)
865 panic("msg_first/last screwed up #3");
866 msqptr->msg_last =
867 previous;
868 }
869 }
870 break;
871 }
872 previous = msghdr;
873 prev = &(msghdr->msg_next);
874 }
875 }
876
877 /*
878 * We've either extracted the msghdr for the appropriate
879 * message or there isn't one.
880 * If there is one then bail out of this loop.
881 */
882
883 if (msghdr != NULL)
884 break;
885
886 /*
887 * Hmph! No message found. Does the user want to wait?
888 */
889
890 if ((msgflg & IPC_NOWAIT) != 0) {
891#ifdef MSG_DEBUG_OK
892 printf("no appropriate message found (msgtyp=%d)\n",
893 msgtyp);
894#endif
895 /* The SVID says to return ENOMSG. */
896#ifdef ENOMSG
897 return(ENOMSG);
898#else
899 /* Unfortunately, BSD doesn't define that code yet! */
900 return(EAGAIN);
901#endif
902 }
903
904 /*
905 * Wait for something to happen
906 */
907
908#ifdef MSG_DEBUG_OK
909 printf("msgrcv: goodnight\n");
910#endif
911 eval = tsleep((caddr_t)msqptr, (PZERO - 4) | PCATCH, "msgwait",
912 0);
913#ifdef MSG_DEBUG_OK
914 printf("msgrcv: good morning (eval=%d)\n", eval);
915#endif
916
917 if (eval != 0) {
918#ifdef MSG_DEBUG_OK
919 printf("msgsnd: interrupted system call\n");
920#endif
921 return(EINTR);
922 }
923
924 /*
925 * Make sure that the msq queue still exists
926 */
927
928 if (msqptr->msg_qbytes == 0 ||
929 msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
930#ifdef MSG_DEBUG_OK
931 printf("msqid deleted\n");
932#endif
933 /* The SVID says to return EIDRM. */
934#ifdef EIDRM
935 return(EIDRM);
936#else
937 /* Unfortunately, BSD doesn't define that code yet! */
938 return(EINVAL);
939#endif
940 }
941 }
942
943 /*
944 * Return the message to the user.
945 *
946 * First, do the bookkeeping (before we risk being interrupted).
947 */
948
949 msqptr->msg_cbytes -= msghdr->msg_ts;
950 msqptr->msg_qnum--;
951 msqptr->msg_lrpid = p->p_pid;
952 msqptr->msg_rtime = time.tv_sec;
953
954 /*
955 * Make msgsz the actual amount that we'll be returning.
956 * Note that this effectively truncates the message if it is too long
957 * (since msgsz is never increased).
958 */
959
960#ifdef MSG_DEBUG_OK
961 printf("found a message, msgsz=%d, msg_ts=%d\n", msgsz,
962 msghdr->msg_ts);
963#endif
964 if (msgsz > msghdr->msg_ts)
965 msgsz = msghdr->msg_ts;
966
967 /*
968 * Return the type to the user.
969 */
970
971 eval = copyout((caddr_t)&(msghdr->msg_type), user_msgp,
972 sizeof(msghdr->msg_type));
973 if (eval != 0) {
974#ifdef MSG_DEBUG_OK
975 printf("error (%d) copying out message type\n", eval);
976#endif
977 msg_freehdr(msghdr);
978 wakeup((caddr_t)msqptr);
979 return(eval);
980 }
981 user_msgp += sizeof(msghdr->msg_type);
982
983 /*
984 * Return the segments to the user
985 */
986
987 next = msghdr->msg_spot;
988 for (len = 0; len < msgsz; len += msginfo.msgssz) {
989 size_t tlen;
990
991 if (msgsz > msginfo.msgssz)
992 tlen = msginfo.msgssz;
993 else
994 tlen = msgsz;
995 if (next <= -1)
996 panic("next too low #3");
997 if (next >= msginfo.msgseg)
998 panic("next out of range #3");
999 eval = copyout((caddr_t)&msgpool[next * msginfo.msgssz],
1000 user_msgp, tlen);
1001 if (eval != 0) {
1002#ifdef MSG_DEBUG_OK
1003 printf("error (%d) copying out message segment\n",
1004 eval);
1005#endif
1006 msg_freehdr(msghdr);
1007 wakeup((caddr_t)msqptr);
1008 return(eval);
1009 }
1010 user_msgp += tlen;
1011 next = msgmaps[next].next;
1012 }
1013
1014 /*
1015 * Done, return the actual number of bytes copied out.
1016 */
1017
1018 msg_freehdr(msghdr);
1019 wakeup((caddr_t)msqptr);
1020 *retval = msgsz;
1021 return(0);
1022}