Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
/*	$NetBSD: linux_ipc.c,v 1.56.4.1 2019/09/13 06:25:25 martin Exp $	*/

/*-
 * Copyright (c) 1995, 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Frank van der Linden and Eric Haszlakiewicz.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: linux_ipc.c,v 1.56.4.1 2019/09/13 06:25:25 martin Exp $");

#if defined(_KERNEL_OPT)
#include "opt_sysv.h"
#endif

#include <sys/param.h>
#include <sys/shm.h>
#include <sys/sem.h>
#include <sys/msg.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/vnode.h>

#include <sys/mount.h>
#include <sys/syscallargs.h>

#include <compat/linux/common/linux_types.h>
#include <compat/linux/common/linux_signal.h>
#include <compat/linux/common/linux_util.h>
#include <compat/linux/common/linux_ipc.h>
#include <compat/linux/common/linux_msg.h>
#include <compat/linux/common/linux_shm.h>
#include <compat/linux/common/linux_sem.h>

#include <compat/linux/linux_syscallargs.h>
#include <compat/linux/linux_syscall.h>

#include <compat/linux/common/linux_ipccall.h>
#include <compat/linux/common/linux_machdep.h>

/*
 * Note: Not all linux architechtures have explicit versions
 *	of the SYSV* syscalls.  On the ones that don't
 *	we pretend that they are defined anyway.  *_args and
 *	prototypes are defined in individual headers;
 *	syscalls.master lists those syscalls as NOARGS.
 *
 *	The functions in multiarch are the ones that just need
 *	the arguments shuffled around and then use the
 *	normal NetBSD syscall.
 *
 * Function in multiarch:
 *	linux_sys_ipc		: linux_ipccall.c
 *	linux_semop		: linux_ipccall.c
 *	linux_semget		: linux_ipccall.c
 *	linux_msgsnd		: linux_ipccall.c
 *	linux_msgrcv		: linux_ipccall.c
 *	linux_msgget		: linux_ipccall.c
 *	linux_shmdt		: linux_ipccall.c
 *	linux_shmget		: linux_ipccall.c
 */

#if defined (SYSVSEM) || defined(SYSVSHM) || defined(SYSVMSG)
/*
 * Convert between Linux and NetBSD ipc_perm structures. Only the
 * order of the fields is different.
 */
void
linux_to_bsd_ipc_perm(struct linux_ipc_perm *lpp, struct ipc_perm *bpp)
{

	bpp->_key = lpp->l_key;
	bpp->uid = lpp->l_uid;
	bpp->gid = lpp->l_gid;
	bpp->cuid = lpp->l_cuid;
	bpp->cgid = lpp->l_cgid;
	bpp->mode = lpp->l_mode;
	bpp->_seq = lpp->l_seq;
}

void
linux_to_bsd_ipc64_perm(struct linux_ipc64_perm *lpp, struct ipc_perm *bpp)
{
	bpp->_key = lpp->l_key;
	bpp->uid = lpp->l_uid;
	bpp->gid = lpp->l_gid;
	bpp->cuid = lpp->l_cuid;
	bpp->cgid = lpp->l_cgid;
	bpp->mode = lpp->l_mode;
	bpp->_seq = lpp->l_seq;
}

void
bsd_to_linux_ipc_perm(struct ipc_perm *bpp, struct linux_ipc_perm *lpp)
{

	memset(lpp, 0, sizeof *lpp);
	lpp->l_key = bpp->_key;
	lpp->l_uid = bpp->uid;
	lpp->l_gid = bpp->gid;
	lpp->l_cuid = bpp->cuid;
	lpp->l_cgid = bpp->cgid;
	lpp->l_mode = bpp->mode;
	lpp->l_seq = bpp->_seq;
}

void
bsd_to_linux_ipc64_perm(struct ipc_perm *bpp, struct linux_ipc64_perm *lpp)
{

	memset(lpp, 0, sizeof *lpp);
	lpp->l_key = bpp->_key;
	lpp->l_uid = bpp->uid;
	lpp->l_gid = bpp->gid;
	lpp->l_cuid = bpp->cuid;
	lpp->l_cgid = bpp->cgid;
	lpp->l_mode = bpp->mode;
	lpp->l_seq = bpp->_seq;
}

#endif

#ifdef SYSVSEM
/*
 * Semaphore operations. Most constants and structures are the same on
 * both systems. Only semctl() needs some extra work.
 */

/*
 * Convert between Linux and NetBSD semid_ds structures.
 */
void
bsd_to_linux_semid_ds(struct semid_ds *bs, struct linux_semid_ds *ls)
{

	memset(ls, 0, sizeof *ls);
	bsd_to_linux_ipc_perm(&bs->sem_perm, &ls->l_sem_perm);
	ls->l_sem_otime = bs->sem_otime;
	ls->l_sem_ctime = bs->sem_ctime;
	ls->l_sem_nsems = bs->sem_nsems;
}

void
bsd_to_linux_semid64_ds(struct semid_ds *bs, struct linux_semid64_ds *ls)
{

	memset(ls, 0, sizeof *ls);
	bsd_to_linux_ipc64_perm(&bs->sem_perm, &ls->l_sem_perm);
	ls->l_sem_otime = bs->sem_otime;
	ls->l_sem_ctime = bs->sem_ctime;
	ls->l_sem_nsems = bs->sem_nsems;
}

void
linux_to_bsd_semid_ds(struct linux_semid_ds *ls, struct semid_ds *bs)
{

	linux_to_bsd_ipc_perm(&ls->l_sem_perm, &bs->sem_perm);
	bs->sem_otime = ls->l_sem_otime;
	bs->sem_ctime = ls->l_sem_ctime;
	bs->sem_nsems = ls->l_sem_nsems;
}

void
linux_to_bsd_semid64_ds(struct linux_semid64_ds *ls, struct semid_ds *bs)
{

	linux_to_bsd_ipc64_perm(&ls->l_sem_perm, &bs->sem_perm);
	bs->sem_otime = ls->l_sem_otime;
	bs->sem_ctime = ls->l_sem_ctime;
	bs->sem_nsems = ls->l_sem_nsems;
}

/*
 * Most of this can be handled by directly passing the arguments on; we
 * just need to frob the `cmd' and convert the semid_ds and semun.
 */
int
linux_sys_semctl(struct lwp *l, const struct linux_sys_semctl_args *uap, register_t *retval)
{
	/* {
		syscallarg(int) semid;
		syscallarg(int) semnum;
		syscallarg(int) cmd;
		syscallarg(union linux_semun) arg;
	} */
	struct semid_ds sembuf;
	struct linux_semid_ds lsembuf;
	struct linux_semid64_ds lsembuf64;
	union __semun semun;
	int cmd, lcmd, error;
	void *pass_arg = NULL;

	lcmd = SCARG(uap, cmd);
#ifdef LINUX_IPC_FORCE64
	lcmd |= LINUX_IPC_64;
#endif

	switch (lcmd & ~LINUX_IPC_64) {
	case LINUX_IPC_SET:
		if (lcmd & LINUX_IPC_64) {
			error = copyin(SCARG(uap, arg).l_buf, &lsembuf64,
		    	    sizeof(lsembuf64));
			linux_to_bsd_semid64_ds(&lsembuf64, &sembuf);
		} else {
			error = copyin(SCARG(uap, arg).l_buf, &lsembuf,
		    	   sizeof(lsembuf));
			linux_to_bsd_semid_ds(&lsembuf, &sembuf);
		}
		if (error)
			return (error);
		pass_arg = &sembuf;
		cmd = IPC_SET;
		break;

	case LINUX_IPC_STAT:
		pass_arg = &sembuf;
		cmd = IPC_STAT;
		break;

	case LINUX_IPC_RMID:
		cmd = IPC_RMID;
		break;

	case LINUX_GETVAL:
		cmd = GETVAL;
		break;

	case LINUX_GETPID:
		cmd = GETPID;
		break;

	case LINUX_GETNCNT:
		cmd = GETNCNT;
		break;

	case LINUX_GETZCNT:
		cmd = GETZCNT;
		break;

	case LINUX_GETALL:
		pass_arg = &semun;
		semun.array = SCARG(uap, arg).l_array;
		cmd = GETALL;
		break;

	case LINUX_SETVAL:
		pass_arg = &semun;
		semun.val = SCARG(uap, arg).l_val;
		cmd = SETVAL;
		break;

	case LINUX_SETALL:
		pass_arg = &semun;
		semun.array = SCARG(uap, arg).l_array;
		cmd = SETALL;
		break;

	default:
		return (EINVAL);
	}

	error = semctl1(l, SCARG(uap, semid), SCARG(uap, semnum), cmd,
	    pass_arg, retval);
	if (error)
		return error;

	switch (lcmd) {
	case LINUX_IPC_STAT:
		bsd_to_linux_semid_ds(&sembuf, &lsembuf);
		error = copyout(&lsembuf, SCARG(uap, arg).l_buf,
		    sizeof(lsembuf));
		break;
	case LINUX_IPC_STAT | LINUX_IPC_64:
		bsd_to_linux_semid64_ds(&sembuf, &lsembuf64);
		error = copyout(&lsembuf64, SCARG(uap, arg).l_buf,
		    sizeof(lsembuf64));
		break;
	default:
		break;
	}

	return (error);
}
#endif /* SYSVSEM */

#ifdef SYSVMSG

void
linux_to_bsd_msqid_ds(struct linux_msqid_ds *lmp, struct msqid_ds *bmp)
{

	memset(bmp, 0, sizeof(*bmp));
	linux_to_bsd_ipc_perm(&lmp->l_msg_perm, &bmp->msg_perm);
	bmp->_msg_cbytes = lmp->l_msg_cbytes;
	bmp->msg_qnum = lmp->l_msg_qnum;
	bmp->msg_qbytes = lmp->l_msg_qbytes;
	bmp->msg_lspid = lmp->l_msg_lspid;
	bmp->msg_lrpid = lmp->l_msg_lrpid;
	bmp->msg_stime = lmp->l_msg_stime;
	bmp->msg_rtime = lmp->l_msg_rtime;
	bmp->msg_ctime = lmp->l_msg_ctime;
}

void
linux_to_bsd_msqid64_ds(struct linux_msqid64_ds *lmp, struct msqid_ds *bmp)
{

	memset(bmp, 0, sizeof(*bmp));
	linux_to_bsd_ipc64_perm(&lmp->l_msg_perm, &bmp->msg_perm);
	bmp->_msg_cbytes = lmp->l_msg_cbytes;
	bmp->msg_stime = lmp->l_msg_stime;
	bmp->msg_rtime = lmp->l_msg_rtime;
	bmp->msg_ctime = lmp->l_msg_ctime;
	bmp->msg_qnum = lmp->l_msg_qnum;
	bmp->msg_qbytes = lmp->l_msg_qbytes;
	bmp->msg_lspid = lmp->l_msg_lspid;
	bmp->msg_lrpid = lmp->l_msg_lrpid;
}

void
bsd_to_linux_msqid_ds(struct msqid_ds *bmp, struct linux_msqid_ds *lmp)
{

	memset(lmp, 0, sizeof(*lmp));
	bsd_to_linux_ipc_perm(&bmp->msg_perm, &lmp->l_msg_perm);
	lmp->l_msg_cbytes = bmp->_msg_cbytes;
	lmp->l_msg_qnum = bmp->msg_qnum;
	lmp->l_msg_qbytes = bmp->msg_qbytes;
	lmp->l_msg_lspid = bmp->msg_lspid;
	lmp->l_msg_lrpid = bmp->msg_lrpid;
	lmp->l_msg_stime = bmp->msg_stime;
	lmp->l_msg_rtime = bmp->msg_rtime;
	lmp->l_msg_ctime = bmp->msg_ctime;
}

void
bsd_to_linux_msqid64_ds(struct msqid_ds *bmp, struct linux_msqid64_ds *lmp)
{

	memset(lmp, 0, sizeof(*lmp));
	bsd_to_linux_ipc64_perm(&bmp->msg_perm, &lmp->l_msg_perm);
	lmp->l_msg_cbytes = bmp->_msg_cbytes;
	lmp->l_msg_stime = bmp->msg_stime;
	lmp->l_msg_rtime = bmp->msg_rtime;
	lmp->l_msg_ctime = bmp->msg_ctime;
	lmp->l_msg_cbytes = bmp->_msg_cbytes;
	lmp->l_msg_qnum = bmp->msg_qnum;
	lmp->l_msg_qbytes = bmp->msg_qbytes;
	lmp->l_msg_lspid = bmp->msg_lspid;
	lmp->l_msg_lrpid = bmp->msg_lrpid;
}

int
linux_sys_msgctl(struct lwp *l, const struct linux_sys_msgctl_args *uap, register_t *retval)
{
	/* {
		syscallarg(int) msqid;
		syscallarg(int) cmd;
		syscallarg(struct linux_msqid_ds *) buf;
	} */
	struct msqid_ds bm, *bmp = NULL;
	struct linux_msqid_ds lm;
	struct linux_msqid64_ds lm64;
	int cmd, lcmd, error;

	lcmd = SCARG(uap, cmd);
#ifdef LINUX_IPC_FORCE64
	lcmd |= LINUX_IPC_64;
#endif

	switch (lcmd & ~LINUX_IPC_64) {
	case LINUX_IPC_STAT:
		cmd = IPC_STAT;
		bmp = &bm;
		break;
	case LINUX_IPC_SET:
		if (lcmd & LINUX_IPC_64) {
			error = copyin(SCARG(uap, buf), &lm64, sizeof lm64);
			linux_to_bsd_msqid64_ds(&lm64, &bm);
		} else {
			error = copyin(SCARG(uap, buf), &lm, sizeof lm);
			linux_to_bsd_msqid_ds(&lm, &bm);
		}
		if (error)
			return error;
		cmd = IPC_SET;
		bmp = &bm;
		break;
	case LINUX_IPC_RMID:
		cmd = IPC_RMID;
		break;
	default:
		return EINVAL;
	}

	if ((error = msgctl1(l, SCARG(uap, msqid), cmd, bmp)))
		return error;

	switch (lcmd) {
	case LINUX_IPC_STAT:
		bsd_to_linux_msqid_ds(&bm, &lm);
		error = copyout(&lm, SCARG(uap, buf), sizeof lm);
		break;
	case LINUX_IPC_STAT|LINUX_IPC_64:
		bsd_to_linux_msqid64_ds(&bm, &lm64);
		error = copyout(&lm64, SCARG(uap, buf), sizeof lm64);
		break;
	default:
		break;
	}

	return error;
}
#endif /* SYSVMSG */

#ifdef SYSVSHM
/*
 * shmget(2). Just make sure the Linux-compatible shmat() semantics
 * is enabled for the segment, so that shmat() succeeds even when
 * the segment would be removed.
 */
int
linux_sys_shmget(struct lwp *l, const struct linux_sys_shmget_args *uap, register_t *retval)
{
	/* {
		syscallarg(key_t) key;
		syscallarg(size_t) size;
		syscallarg(int) shmflg;
	} */
	struct sys_shmget_args bsd_ua;

	SCARG(&bsd_ua, key) = SCARG(uap, key);
	SCARG(&bsd_ua, size) = SCARG(uap, size);
	SCARG(&bsd_ua, shmflg) = SCARG(uap, shmflg) | _SHM_RMLINGER;

	return sys_shmget(l, &bsd_ua, retval);
}

/*
 * shmat(2). Very straightforward, except that Linux passes a pointer
 * in which the return value is to be passed. This is subsequently
 * handled by libc, apparently.
 */
#ifndef __amd64__
int
linux_sys_shmat(struct lwp *l, const struct linux_sys_shmat_args *uap, register_t *retval)
{
	/* {
		syscallarg(int) shmid;
		syscallarg(void *) shmaddr;
		syscallarg(int) shmflg;
		syscallarg(u_long *) raddr;
	} */
	int error;

	if ((error = sys_shmat(l, (const void *)uap, retval)))
		return error;

	if ((error = copyout(&retval[0], SCARG(uap, raddr), sizeof retval[0])))
		return error;

	retval[0] = 0;
	return 0;
}
#endif /* __amd64__ */

/*
 * Convert between Linux and NetBSD shmid_ds structures.
 * The order of the fields is once again the difference, and
 * we also need a place to store the internal data pointer
 * in, which is unfortunately stored in this structure.
 *
 * We abuse a Linux internal field for that.
 */
void
linux_to_bsd_shmid_ds(struct linux_shmid_ds *lsp, struct shmid_ds *bsp)
{

	linux_to_bsd_ipc_perm(&lsp->l_shm_perm, &bsp->shm_perm);
	bsp->shm_segsz = lsp->l_shm_segsz;
	bsp->shm_lpid = lsp->l_shm_lpid;
	bsp->shm_cpid = lsp->l_shm_cpid;
	bsp->shm_nattch = lsp->l_shm_nattch;
	bsp->shm_atime = lsp->l_shm_atime;
	bsp->shm_dtime = lsp->l_shm_dtime;
	bsp->shm_ctime = lsp->l_shm_ctime;
}

void
linux_to_bsd_shmid64_ds(struct linux_shmid64_ds *lsp, struct shmid_ds *bsp)
{

	linux_to_bsd_ipc64_perm(&lsp->l_shm_perm, &bsp->shm_perm);
	bsp->shm_segsz = lsp->l_shm_segsz;
	bsp->shm_lpid = lsp->l_shm_lpid;
	bsp->shm_cpid = lsp->l_shm_cpid;
	bsp->shm_nattch = lsp->l_shm_nattch;
	bsp->shm_atime = lsp->l_shm_atime;
	bsp->shm_dtime = lsp->l_shm_dtime;
	bsp->shm_ctime = lsp->l_shm_ctime;
}

void
bsd_to_linux_shmid_ds(struct shmid_ds *bsp, struct linux_shmid_ds *lsp)
{

	memset(lsp, 0, sizeof *lsp);
	bsd_to_linux_ipc_perm(&bsp->shm_perm, &lsp->l_shm_perm);
	lsp->l_shm_segsz = bsp->shm_segsz;
	lsp->l_shm_lpid = bsp->shm_lpid;
	lsp->l_shm_cpid = bsp->shm_cpid;
	lsp->l_shm_nattch = bsp->shm_nattch;
	lsp->l_shm_atime = bsp->shm_atime;
	lsp->l_shm_dtime = bsp->shm_dtime;
	lsp->l_shm_ctime = bsp->shm_ctime;
}

void
bsd_to_linux_shmid64_ds(struct shmid_ds *bsp, struct linux_shmid64_ds *lsp)
{

	memset(lsp, 0, sizeof *lsp);
	bsd_to_linux_ipc64_perm(&bsp->shm_perm, &lsp->l_shm_perm);
	lsp->l_shm_segsz = bsp->shm_segsz;
	lsp->l_shm_lpid = bsp->shm_lpid;
	lsp->l_shm_cpid = bsp->shm_cpid;
	lsp->l_shm_nattch = bsp->shm_nattch;
	lsp->l_shm_atime = bsp->shm_atime;
	lsp->l_shm_dtime = bsp->shm_dtime;
	lsp->l_shm_ctime = bsp->shm_ctime;
}

/*
 * shmctl.
 *
 * The usual structure conversion and massaging is done.
 */
int
linux_sys_shmctl(struct lwp *l, const struct linux_sys_shmctl_args *uap, register_t *retval)
{
	/* {
		syscallarg(int) shmid;
		syscallarg(int) cmd;
		syscallarg(struct linux_shmid_ds *) buf;
	} */
	struct shmid_ds bs;
	struct ipc_perm perm;
	struct linux_shmid_ds ls;
	struct linux_shmid64_ds ls64;
	struct linux_shminfo64 lsi64;
	struct linux_shm_info lsi;
	int error, i, cmd, shmid;

	shmid = SCARG(uap, shmid);
	cmd = SCARG(uap, cmd);
#ifdef LINUX_IPC_FORCE64
	cmd |= LINUX_IPC_64;
#endif

	switch (cmd & ~LINUX_IPC_64) {
	case LINUX_SHM_STAT:
		error = shm_find_segment_perm_by_index(shmid, &perm);
		if (error)
			return error;
		shmid = IXSEQ_TO_IPCID(shmid, perm);
		retval[0] = shmid;
		/*FALLTHROUGH*/

	case LINUX_IPC_STAT:
		error = shmctl1(l, shmid, IPC_STAT, &bs);
		if (error != 0)
			return error;
		if (cmd & LINUX_IPC_64) {
			bsd_to_linux_shmid64_ds(&bs, &ls64);
			error = copyout(&ls64, SCARG(uap, buf), sizeof ls64);
		} else {
			bsd_to_linux_shmid_ds(&bs, &ls);
			error = copyout(&ls, SCARG(uap, buf), sizeof ls);
		}
		return error;

	case LINUX_IPC_SET:
		if (cmd & LINUX_IPC_64) {
			error = copyin(SCARG(uap, buf), &ls64, sizeof ls64);
			linux_to_bsd_shmid64_ds(&ls64, &bs);
		} else {
			error = copyin(SCARG(uap, buf), &ls, sizeof ls);
			linux_to_bsd_shmid_ds(&ls, &bs);
		}
		if (error != 0)
			return error;
		return shmctl1(l, shmid, IPC_SET, &bs);

	case LINUX_IPC_RMID:
		return shmctl1(l, shmid, IPC_RMID, NULL);

	case LINUX_SHM_LOCK:
		return shmctl1(l, shmid, SHM_LOCK, NULL);

	case LINUX_SHM_UNLOCK:
		return shmctl1(l, shmid, SHM_UNLOCK, NULL);

	case LINUX_IPC_INFO:
		memset(&lsi64, 0, sizeof lsi64);
		lsi64.l_shmmax = shminfo.shmmax;
		lsi64.l_shmmin = shminfo.shmmin;
		lsi64.l_shmmni = shminfo.shmmni;
		lsi64.l_shmseg = shminfo.shmseg;
		lsi64.l_shmall = shminfo.shmall;
		for (i = shminfo.shmmni - 1; i > 0; i--)
			if (shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED)
				break;
		retval[0] = i;
		return copyout(&lsi64, SCARG(uap, buf), sizeof lsi64);

	case LINUX_SHM_INFO:
		(void)memset(&lsi, 0, sizeof lsi);
		lsi.l_used_ids = shm_nused;
		for (i = 0; i < shminfo.shmmni; i++)
			if (shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED)
				lsi.l_shm_tot +=
				    round_page(shmsegs[i].shm_segsz) /
				    uvmexp.pagesize;
		lsi.l_shm_rss = 0;
		lsi.l_shm_swp = 0;
		lsi.l_swap_attempts = 0;
		lsi.l_swap_successes = 0;
		for (i = shminfo.shmmni - 1; i > 0; i--)
			if (shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED)
				break;
		retval[0] = i;
		return copyout(&lsi, SCARG(uap, buf), sizeof lsi);

	default:
#ifdef DEBUG
		printf("linux_sys_shmctl cmd %d\n", SCARG(uap, cmd));
#endif
		return EINVAL;
	}
}
#endif /* SYSVSHM */