xref: /netbsd-src/sys/kern/kern_ktrace.c (revision 404fbe5fb94ca1e054339640cabb2801ce52dd30)
1 /*	$NetBSD: kern_ktrace.c,v 1.148 2009/01/11 02:45:52 christos Exp $	*/
2 
3 /*-
4  * Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Andrew Doran.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 /*
33  * Copyright (c) 1989, 1993
34  *	The Regents of the University of California.  All rights reserved.
35  *
36  * Redistribution and use in source and binary forms, with or without
37  * modification, are permitted provided that the following conditions
38  * are met:
39  * 1. Redistributions of source code must retain the above copyright
40  *    notice, this list of conditions and the following disclaimer.
41  * 2. Redistributions in binary form must reproduce the above copyright
42  *    notice, this list of conditions and the following disclaimer in the
43  *    documentation and/or other materials provided with the distribution.
44  * 3. Neither the name of the University nor the names of its contributors
45  *    may be used to endorse or promote products derived from this software
46  *    without specific prior written permission.
47  *
48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58  * SUCH DAMAGE.
59  *
60  *	@(#)kern_ktrace.c	8.5 (Berkeley) 5/14/95
61  */
62 
63 #include <sys/cdefs.h>
64 __KERNEL_RCSID(0, "$NetBSD: kern_ktrace.c,v 1.148 2009/01/11 02:45:52 christos Exp $");
65 
66 #include <sys/param.h>
67 #include <sys/systm.h>
68 #include <sys/proc.h>
69 #include <sys/file.h>
70 #include <sys/namei.h>
71 #include <sys/vnode.h>
72 #include <sys/kernel.h>
73 #include <sys/kthread.h>
74 #include <sys/ktrace.h>
75 #include <sys/kmem.h>
76 #include <sys/syslog.h>
77 #include <sys/filedesc.h>
78 #include <sys/ioctl.h>
79 #include <sys/callout.h>
80 #include <sys/kauth.h>
81 
82 #include <sys/mount.h>
83 #include <sys/sa.h>
84 #include <sys/syscallargs.h>
85 
86 /*
87  * TODO:
88  *	- need better error reporting?
89  *	- userland utility to sort ktrace.out by timestamp.
90  *	- keep minimum information in ktrace_entry when rest of alloc failed.
91  *	- per trace control of configurable parameters.
92  */
93 
94 struct ktrace_entry {
95 	TAILQ_ENTRY(ktrace_entry) kte_list;
96 	struct	ktr_header kte_kth;
97 	void	*kte_buf;
98 	size_t	kte_bufsz;
99 #define	KTE_SPACE		32
100 	uint8_t kte_space[KTE_SPACE];
101 };
102 
103 struct ktr_desc {
104 	TAILQ_ENTRY(ktr_desc) ktd_list;
105 	int ktd_flags;
106 #define	KTDF_WAIT		0x0001
107 #define	KTDF_DONE		0x0002
108 #define	KTDF_BLOCKING		0x0004
109 #define	KTDF_INTERACTIVE	0x0008
110 	int ktd_error;
111 #define	KTDE_ENOMEM		0x0001
112 #define	KTDE_ENOSPC		0x0002
113 	int ktd_errcnt;
114 	int ktd_ref;			/* # of reference */
115 	int ktd_qcount;			/* # of entry in the queue */
116 
117 	/*
118 	 * Params to control behaviour.
119 	 */
120 	int ktd_delayqcnt;		/* # of entry allowed to delay */
121 	int ktd_wakedelay;		/* delay of wakeup in *tick* */
122 	int ktd_intrwakdl;		/* ditto, but when interactive */
123 
124 	file_t *ktd_fp;			/* trace output file */
125 	lwp_t *ktd_lwp;			/* our kernel thread */
126 	TAILQ_HEAD(, ktrace_entry) ktd_queue;
127 	callout_t ktd_wakch;		/* delayed wakeup */
128 	kcondvar_t ktd_sync_cv;
129 	kcondvar_t ktd_cv;
130 };
131 
132 static int	ktealloc(struct ktrace_entry **, void **, lwp_t *, int,
133 			 size_t);
134 static void	ktrwrite(struct ktr_desc *, struct ktrace_entry *);
135 static int	ktrace_common(lwp_t *, int, int, int, file_t *);
136 static int	ktrops(lwp_t *, struct proc *, int, int,
137 		    struct ktr_desc *);
138 static int	ktrsetchildren(lwp_t *, struct proc *, int, int,
139 		    struct ktr_desc *);
140 static int	ktrcanset(lwp_t *, struct proc *);
141 static int	ktrsamefile(file_t *, file_t *);
142 static void	ktr_kmem(lwp_t *, int, const void *, size_t);
143 static void	ktr_io(lwp_t *, int, enum uio_rw, struct iovec *, size_t);
144 
145 static struct ktr_desc *
146 		ktd_lookup(file_t *);
147 static void	ktdrel(struct ktr_desc *);
148 static void	ktdref(struct ktr_desc *);
149 static void	ktraddentry(lwp_t *, struct ktrace_entry *, int);
150 /* Flags for ktraddentry (3rd arg) */
151 #define	KTA_NOWAIT		0x0000
152 #define	KTA_WAITOK		0x0001
153 #define	KTA_LARGE		0x0002
154 static void	ktefree(struct ktrace_entry *);
155 static void	ktd_logerrl(struct ktr_desc *, int);
156 static void	ktrace_thread(void *);
157 static int	ktrderefall(struct ktr_desc *, int);
158 
159 /*
160  * Default vaules.
161  */
162 #define	KTD_MAXENTRY		1000	/* XXX: tune */
163 #define	KTD_TIMEOUT		5	/* XXX: tune */
164 #define	KTD_DELAYQCNT		100	/* XXX: tune */
165 #define	KTD_WAKEDELAY		5000	/* XXX: tune */
166 #define	KTD_INTRWAKDL		100	/* XXX: tune */
167 
168 /*
169  * Patchable variables.
170  */
171 int ktd_maxentry = KTD_MAXENTRY;	/* max # of entry in the queue */
172 int ktd_timeout = KTD_TIMEOUT;		/* timeout in seconds */
173 int ktd_delayqcnt = KTD_DELAYQCNT;	/* # of entry allowed to delay */
174 int ktd_wakedelay = KTD_WAKEDELAY;	/* delay of wakeup in *ms* */
175 int ktd_intrwakdl = KTD_INTRWAKDL;	/* ditto, but when interactive */
176 
177 kmutex_t ktrace_lock;
178 int ktrace_on;
179 static TAILQ_HEAD(, ktr_desc) ktdq = TAILQ_HEAD_INITIALIZER(ktdq);
180 static pool_cache_t kte_cache;
181 
182 static void
183 ktd_wakeup(struct ktr_desc *ktd)
184 {
185 
186 	callout_stop(&ktd->ktd_wakch);
187 	cv_signal(&ktd->ktd_cv);
188 }
189 
190 static void
191 ktd_callout(void *arg)
192 {
193 
194 	mutex_enter(&ktrace_lock);
195 	ktd_wakeup(arg);
196 	mutex_exit(&ktrace_lock);
197 }
198 
199 static void
200 ktd_logerrl(struct ktr_desc *ktd, int error)
201 {
202 
203 	ktd->ktd_error |= error;
204 	ktd->ktd_errcnt++;
205 }
206 
207 #if 0
208 static void
209 ktd_logerr(struct proc *p, int error)
210 {
211 	struct ktr_desc *ktd;
212 
213 	KASSERT(mutex_owned(&ktrace_lock));
214 
215 	ktd = p->p_tracep;
216 	if (ktd == NULL)
217 		return;
218 
219 	ktd_logerrl(ktd, error);
220 }
221 #endif
222 
223 static inline int
224 ktrenter(lwp_t *l)
225 {
226 
227 	if ((l->l_pflag & LP_KTRACTIVE) != 0)
228 		return 1;
229 	l->l_pflag |= LP_KTRACTIVE;
230 	return 0;
231 }
232 
233 static inline void
234 ktrexit(lwp_t *l)
235 {
236 
237 	l->l_pflag &= ~LP_KTRACTIVE;
238 }
239 
240 /*
241  * Initialise the ktrace system.
242  */
243 void
244 ktrinit(void)
245 {
246 
247 	mutex_init(&ktrace_lock, MUTEX_DEFAULT, IPL_NONE);
248 	kte_cache = pool_cache_init(sizeof(struct ktrace_entry), 0, 0, 0,
249 	    "ktrace", &pool_allocator_nointr, IPL_NONE, NULL, NULL, NULL);
250 }
251 
252 /*
253  * Release a reference.  Called with ktrace_lock held.
254  */
255 void
256 ktdrel(struct ktr_desc *ktd)
257 {
258 
259 	KASSERT(mutex_owned(&ktrace_lock));
260 
261 	KDASSERT(ktd->ktd_ref != 0);
262 	KASSERT(ktd->ktd_ref > 0);
263 	KASSERT(ktrace_on > 0);
264 	ktrace_on--;
265 	if (--ktd->ktd_ref <= 0) {
266 		ktd->ktd_flags |= KTDF_DONE;
267 		cv_signal(&ktd->ktd_cv);
268 	}
269 }
270 
271 void
272 ktdref(struct ktr_desc *ktd)
273 {
274 
275 	KASSERT(mutex_owned(&ktrace_lock));
276 
277 	ktd->ktd_ref++;
278 	ktrace_on++;
279 }
280 
281 struct ktr_desc *
282 ktd_lookup(file_t *fp)
283 {
284 	struct ktr_desc *ktd;
285 
286 	KASSERT(mutex_owned(&ktrace_lock));
287 
288 	for (ktd = TAILQ_FIRST(&ktdq); ktd != NULL;
289 	    ktd = TAILQ_NEXT(ktd, ktd_list)) {
290 		if (ktrsamefile(ktd->ktd_fp, fp)) {
291 			ktdref(ktd);
292 			break;
293 		}
294 	}
295 
296 	return (ktd);
297 }
298 
299 void
300 ktraddentry(lwp_t *l, struct ktrace_entry *kte, int flags)
301 {
302 	struct proc *p = l->l_proc;
303 	struct ktr_desc *ktd;
304 #ifdef DEBUG
305 	struct timeval t1, t2;
306 #endif
307 
308 	mutex_enter(&ktrace_lock);
309 
310 	if (p->p_traceflag & KTRFAC_TRC_EMUL) {
311 		/* Add emulation trace before first entry for this process */
312 		p->p_traceflag &= ~KTRFAC_TRC_EMUL;
313 		mutex_exit(&ktrace_lock);
314 		ktrexit(l);
315 		ktremul();
316 		(void)ktrenter(l);
317 		mutex_enter(&ktrace_lock);
318 	}
319 
320 	/* Tracing may have been cancelled. */
321 	ktd = p->p_tracep;
322 	if (ktd == NULL)
323 		goto freekte;
324 
325 	/*
326 	 * Bump reference count so that the object will remain while
327 	 * we are here.  Note that the trace is controlled by other
328 	 * process.
329 	 */
330 	ktdref(ktd);
331 
332 	if (ktd->ktd_flags & KTDF_DONE)
333 		goto relktd;
334 
335 	if (ktd->ktd_qcount > ktd_maxentry) {
336 		ktd_logerrl(ktd, KTDE_ENOSPC);
337 		goto relktd;
338 	}
339 	TAILQ_INSERT_TAIL(&ktd->ktd_queue, kte, kte_list);
340 	ktd->ktd_qcount++;
341 	if (ktd->ktd_flags & KTDF_BLOCKING)
342 		goto skip_sync;
343 
344 	if (flags & KTA_WAITOK &&
345 	    (/* flags & KTA_LARGE */0 || ktd->ktd_flags & KTDF_WAIT ||
346 	    ktd->ktd_qcount > ktd_maxentry >> 1))
347 		/*
348 		 * Sync with writer thread since we're requesting rather
349 		 * big one or many requests are pending.
350 		 */
351 		do {
352 			ktd->ktd_flags |= KTDF_WAIT;
353 			ktd_wakeup(ktd);
354 #ifdef DEBUG
355 			getmicrouptime(&t1);
356 #endif
357 			if (cv_timedwait(&ktd->ktd_sync_cv, &ktrace_lock,
358 			    ktd_timeout * hz) != 0) {
359 				ktd->ktd_flags |= KTDF_BLOCKING;
360 				/*
361 				 * Maybe the writer thread is blocking
362 				 * completely for some reason, but
363 				 * don't stop target process forever.
364 				 */
365 				log(LOG_NOTICE, "ktrace timeout\n");
366 				break;
367 			}
368 #ifdef DEBUG
369 			getmicrouptime(&t2);
370 			timersub(&t2, &t1, &t2);
371 			if (t2.tv_sec > 0)
372 				log(LOG_NOTICE,
373 				    "ktrace long wait: %lld.%06ld\n",
374 				    (long long)t2.tv_sec, (long)t2.tv_usec);
375 #endif
376 		} while (p->p_tracep == ktd &&
377 		    (ktd->ktd_flags & (KTDF_WAIT | KTDF_DONE)) == KTDF_WAIT);
378 	else {
379 		/* Schedule delayed wakeup */
380 		if (ktd->ktd_qcount > ktd->ktd_delayqcnt)
381 			ktd_wakeup(ktd);	/* Wakeup now */
382 		else if (!callout_pending(&ktd->ktd_wakch))
383 			callout_reset(&ktd->ktd_wakch,
384 			    ktd->ktd_flags & KTDF_INTERACTIVE ?
385 			    ktd->ktd_intrwakdl : ktd->ktd_wakedelay,
386 			    ktd_callout, ktd);
387 	}
388 
389 skip_sync:
390 	ktdrel(ktd);
391 	mutex_exit(&ktrace_lock);
392 	ktrexit(l);
393 	return;
394 
395 relktd:
396 	ktdrel(ktd);
397 
398 freekte:
399 	mutex_exit(&ktrace_lock);
400 	ktefree(kte);
401 	ktrexit(l);
402 }
403 
404 void
405 ktefree(struct ktrace_entry *kte)
406 {
407 
408 	if (kte->kte_buf != kte->kte_space)
409 		kmem_free(kte->kte_buf, kte->kte_bufsz);
410 	pool_cache_put(kte_cache, kte);
411 }
412 
413 /*
414  * "deep" compare of two files for the purposes of clearing a trace.
415  * Returns true if they're the same open file, or if they point at the
416  * same underlying vnode/socket.
417  */
418 
419 int
420 ktrsamefile(file_t *f1, file_t *f2)
421 {
422 
423 	return ((f1 == f2) ||
424 	    ((f1 != NULL) && (f2 != NULL) &&
425 		(f1->f_type == f2->f_type) &&
426 		(f1->f_data == f2->f_data)));
427 }
428 
429 void
430 ktrderef(struct proc *p)
431 {
432 	struct ktr_desc *ktd = p->p_tracep;
433 
434 	KASSERT(mutex_owned(&ktrace_lock));
435 
436 	p->p_traceflag = 0;
437 	if (ktd == NULL)
438 		return;
439 	p->p_tracep = NULL;
440 
441 	cv_broadcast(&ktd->ktd_sync_cv);
442 	ktdrel(ktd);
443 }
444 
445 void
446 ktradref(struct proc *p)
447 {
448 	struct ktr_desc *ktd = p->p_tracep;
449 
450 	KASSERT(mutex_owned(&ktrace_lock));
451 
452 	ktdref(ktd);
453 }
454 
455 int
456 ktrderefall(struct ktr_desc *ktd, int auth)
457 {
458 	lwp_t *curl = curlwp;
459 	struct proc *p;
460 	int error = 0;
461 
462 	mutex_enter(proc_lock);
463 	PROCLIST_FOREACH(p, &allproc) {
464 		if ((p->p_flag & PK_MARKER) != 0 || p->p_tracep != ktd)
465 			continue;
466 		mutex_enter(p->p_lock);
467 		mutex_enter(&ktrace_lock);
468 		if (p->p_tracep == ktd) {
469 			if (!auth || ktrcanset(curl, p))
470 				ktrderef(p);
471 			else
472 				error = EPERM;
473 		}
474 		mutex_exit(&ktrace_lock);
475 		mutex_exit(p->p_lock);
476 	}
477 	mutex_exit(proc_lock);
478 
479 	return error;
480 }
481 
482 int
483 ktealloc(struct ktrace_entry **ktep, void **bufp, lwp_t *l, int type,
484 	 size_t sz)
485 {
486 	struct proc *p = l->l_proc;
487 	struct ktrace_entry *kte;
488 	struct ktr_header *kth;
489 	struct timespec ts;
490 	void *buf;
491 
492 	if (ktrenter(l))
493 		return EAGAIN;
494 
495 	kte = pool_cache_get(kte_cache, PR_WAITOK);
496 	if (sz > sizeof(kte->kte_space)) {
497 		if ((buf = kmem_alloc(sz, KM_SLEEP)) == NULL) {
498 			pool_cache_put(kte_cache, kte);
499 			ktrexit(l);
500 			return ENOMEM;
501 		}
502 	} else
503 		buf = kte->kte_space;
504 
505 	kte->kte_bufsz = sz;
506 	kte->kte_buf = buf;
507 
508 	kth = &kte->kte_kth;
509 	(void)memset(kth, 0, sizeof(*kth));
510 	kth->ktr_len = sz;
511 	kth->ktr_type = type;
512 	kth->ktr_pid = p->p_pid;
513 	memcpy(kth->ktr_comm, p->p_comm, MAXCOMLEN);
514 	kth->ktr_version = KTRFAC_VERSION(p->p_traceflag);
515 
516         nanotime(&ts);
517         switch (KTRFAC_VERSION(p->p_traceflag)) {
518         case 0:
519                 /* This is the original format */
520                 kth->ktr_otv.tv_sec = ts.tv_sec;
521                 kth->ktr_otv.tv_usec = ts.tv_nsec / 1000;
522                 break;
523         case 1:
524 		kth->ktr_olid = l->l_lid;
525                 kth->ktr_ots.tv_sec = ts.tv_sec;
526                 kth->ktr_ots.tv_nsec = ts.tv_nsec;
527                 break;
528         case 2:
529 		kth->ktr_lid = l->l_lid;
530                 kth->ktr_ts.tv_sec = ts.tv_sec;
531                 kth->ktr_ts.tv_nsec = ts.tv_nsec;
532                 break;
533         default:
534                 break;
535         }
536 
537 	*ktep = kte;
538 	*bufp = buf;
539 
540 	return 0;
541 }
542 
543 void
544 ktr_syscall(register_t code, const register_t args[], int narg)
545 {
546 	lwp_t *l = curlwp;
547 	struct proc *p = l->l_proc;
548 	struct ktrace_entry *kte;
549 	struct ktr_syscall *ktp;
550 	register_t *argp;
551 	size_t len;
552 	u_int i;
553 
554 	if (!KTRPOINT(p, KTR_SYSCALL))
555 		return;
556 
557 	len = sizeof(struct ktr_syscall) + narg * sizeof argp[0];
558 
559 	if (ktealloc(&kte, (void *)&ktp, l, KTR_SYSCALL, len))
560 		return;
561 
562 	ktp->ktr_code = code;
563 	ktp->ktr_argsize = narg * sizeof argp[0];
564 	argp = (register_t *)(ktp + 1);
565 	for (i = 0; i < narg; i++)
566 		*argp++ = args[i];
567 
568 	ktraddentry(l, kte, KTA_WAITOK);
569 }
570 
571 void
572 ktr_sysret(register_t code, int error, register_t *retval)
573 {
574 	lwp_t *l = curlwp;
575 	struct ktrace_entry *kte;
576 	struct ktr_sysret *ktp;
577 
578 	if (!KTRPOINT(l->l_proc, KTR_SYSRET))
579 		return;
580 
581 	if (ktealloc(&kte, (void *)&ktp, l, KTR_SYSRET,
582 	    sizeof(struct ktr_sysret)))
583 		return;
584 
585 	ktp->ktr_code = code;
586 	ktp->ktr_eosys = 0;			/* XXX unused */
587 	ktp->ktr_error = error;
588 	ktp->ktr_retval = retval ? retval[0] : 0;
589 	ktp->ktr_retval_1 = retval ? retval[1] : 0;
590 
591 	ktraddentry(l, kte, KTA_WAITOK);
592 }
593 
594 void
595 ktr_namei(const char *path, size_t pathlen)
596 {
597 	lwp_t *l = curlwp;
598 
599 	if (!KTRPOINT(l->l_proc, KTR_NAMEI))
600 		return;
601 
602 	ktr_kmem(l, KTR_NAMEI, path, pathlen);
603 }
604 
605 void
606 ktr_namei2(const char *eroot, size_t erootlen,
607 	  const char *path, size_t pathlen)
608 {
609 	lwp_t *l = curlwp;
610 	struct ktrace_entry *kte;
611 	void *buf;
612 
613 	if (!KTRPOINT(l->l_proc, KTR_NAMEI))
614 		return;
615 
616 	if (ktealloc(&kte, &buf, l, KTR_NAMEI, erootlen + pathlen))
617 		return;
618 	memcpy(buf, eroot, erootlen);
619 	buf = (char *)buf + erootlen;
620 	memcpy(buf, path, pathlen);
621 	ktraddentry(l, kte, KTA_WAITOK);
622 }
623 
624 void
625 ktr_emul(void)
626 {
627 	lwp_t *l = curlwp;
628 	const char *emul = l->l_proc->p_emul->e_name;
629 
630 	if (!KTRPOINT(l->l_proc, KTR_EMUL))
631 		return;
632 
633 	ktr_kmem(l, KTR_EMUL, emul, strlen(emul));
634 }
635 
636 void
637 ktr_execarg(const void *bf, size_t len)
638 {
639 	lwp_t *l = curlwp;
640 
641 	if (!KTRPOINT(l->l_proc, KTR_EXEC_ARG))
642 		return;
643 
644 	ktr_kmem(l, KTR_EXEC_ARG, bf, len);
645 }
646 
647 void
648 ktr_execenv(const void *bf, size_t len)
649 {
650 	lwp_t *l = curlwp;
651 
652 	if (!KTRPOINT(l->l_proc, KTR_EXEC_ENV))
653 		return;
654 
655 	ktr_kmem(l, KTR_EXEC_ENV, bf, len);
656 }
657 
658 static void
659 ktr_kmem(lwp_t *l, int type, const void *bf, size_t len)
660 {
661 	struct ktrace_entry *kte;
662 	void *buf;
663 
664 	if (ktealloc(&kte, &buf, l, type, len))
665 		return;
666 	memcpy(buf, bf, len);
667 	ktraddentry(l, kte, KTA_WAITOK);
668 }
669 
670 static void
671 ktr_io(lwp_t *l, int fd, enum uio_rw rw, struct iovec *iov, size_t len)
672 {
673 	struct ktrace_entry *kte;
674 	struct ktr_genio *ktp;
675 	size_t resid = len, cnt, buflen;
676 	void *cp;
677 
678  next:
679 	buflen = min(PAGE_SIZE, resid + sizeof(struct ktr_genio));
680 
681 	if (ktealloc(&kte, (void *)&ktp, l, KTR_GENIO, buflen))
682 		return;
683 
684 	ktp->ktr_fd = fd;
685 	ktp->ktr_rw = rw;
686 
687 	cp = (void *)(ktp + 1);
688 	buflen -= sizeof(struct ktr_genio);
689 	kte->kte_kth.ktr_len = sizeof(struct ktr_genio);
690 
691 	while (buflen > 0) {
692 		cnt = min(iov->iov_len, buflen);
693 		if (copyin(iov->iov_base, cp, cnt) != 0)
694 			goto out;
695 		kte->kte_kth.ktr_len += cnt;
696 		buflen -= cnt;
697 		resid -= cnt;
698 		iov->iov_len -= cnt;
699 		if (iov->iov_len == 0)
700 			iov++;
701 		else
702 			iov->iov_base = (char *)iov->iov_base + cnt;
703 	}
704 
705 	/*
706 	 * Don't push so many entry at once.  It will cause kmem map
707 	 * shortage.
708 	 */
709 	ktraddentry(l, kte, KTA_WAITOK | KTA_LARGE);
710 	if (resid > 0) {
711 		if (curcpu()->ci_schedstate.spc_flags & SPCF_SHOULDYIELD) {
712 			(void)ktrenter(l);
713 			preempt();
714 			ktrexit(l);
715 		}
716 
717 		goto next;
718 	}
719 
720 	return;
721 
722 out:
723 	ktefree(kte);
724 	ktrexit(l);
725 }
726 
727 void
728 ktr_genio(int fd, enum uio_rw rw, const void *addr, size_t len, int error)
729 {
730 	lwp_t *l = curlwp;
731 	struct iovec iov;
732 
733 	if (!KTRPOINT(l->l_proc, KTR_GENIO) || error != 0)
734 		return;
735 	iov.iov_base = __UNCONST(addr);
736 	iov.iov_len = len;
737 	ktr_io(l, fd, rw, &iov, len);
738 }
739 
740 void
741 ktr_geniov(int fd, enum uio_rw rw, struct iovec *iov, size_t len, int error)
742 {
743 	lwp_t *l = curlwp;
744 
745 	if (!KTRPOINT(l->l_proc, KTR_GENIO) || error != 0)
746 		return;
747 	ktr_io(l, fd, rw, iov, len);
748 }
749 
750 void
751 ktr_mibio(int fd, enum uio_rw rw, const void *addr, size_t len, int error)
752 {
753 	lwp_t *l = curlwp;
754 	struct iovec iov;
755 
756 	if (!KTRPOINT(l->l_proc, KTR_MIB) || error != 0)
757 		return;
758 	iov.iov_base = __UNCONST(addr);
759 	iov.iov_len = len;
760 	ktr_io(l, fd, rw, &iov, len);
761 }
762 
763 void
764 ktr_psig(int sig, sig_t action, const sigset_t *mask,
765 	 const ksiginfo_t *ksi)
766 {
767 	struct ktrace_entry *kte;
768 	lwp_t *l = curlwp;
769 	struct {
770 		struct ktr_psig	kp;
771 		siginfo_t	si;
772 	} *kbuf;
773 
774 	if (!KTRPOINT(l->l_proc, KTR_PSIG))
775 		return;
776 
777 	if (ktealloc(&kte, (void *)&kbuf, l, KTR_PSIG, sizeof(*kbuf)))
778 		return;
779 
780 	kbuf->kp.signo = (char)sig;
781 	kbuf->kp.action = action;
782 	kbuf->kp.mask = *mask;
783 
784 	if (ksi) {
785 		kbuf->kp.code = KSI_TRAPCODE(ksi);
786 		(void)memset(&kbuf->si, 0, sizeof(kbuf->si));
787 		kbuf->si._info = ksi->ksi_info;
788 		kte->kte_kth.ktr_len = sizeof(*kbuf);
789 	} else {
790 		kbuf->kp.code = 0;
791 		kte->kte_kth.ktr_len = sizeof(struct ktr_psig);
792 	}
793 
794 	ktraddentry(l, kte, KTA_WAITOK);
795 }
796 
797 void
798 ktr_csw(int out, int user)
799 {
800 	lwp_t *l = curlwp;
801 	struct proc *p = l->l_proc;
802 	struct ktrace_entry *kte;
803 	struct ktr_csw *kc;
804 
805 	if (!KTRPOINT(p, KTR_CSW))
806 		return;
807 
808 	/*
809 	 * Don't record context switches resulting from blocking on
810 	 * locks; it's too easy to get duff results.
811 	 */
812 	if (l->l_syncobj == &mutex_syncobj || l->l_syncobj == &rw_syncobj)
813 		return;
814 
815 	/*
816 	 * We can't sleep if we're already going to sleep (if original
817 	 * condition is met during sleep, we hang up).
818 	 *
819 	 * XXX This is not ideal: it would be better to maintain a pool
820 	 * of ktes and actually push this to the kthread when context
821 	 * switch happens, however given the points where we are called
822 	 * from that is difficult to do.
823 	 */
824 	if (out) {
825 		struct timespec ts;
826 		if (ktrenter(l))
827 			return;
828 
829 		nanotime(&l->l_ktrcsw);
830 		l->l_pflag |= LP_KTRCSW;
831 		nanotime(&ts);
832 		if (user)
833 			l->l_pflag |= LP_KTRCSWUSER;
834 		else
835 			l->l_pflag &= ~LP_KTRCSWUSER;
836 
837 		ktrexit(l);
838 		return;
839 	}
840 
841 	/*
842 	 * On the way back in, we need to record twice: once for entry, and
843 	 * once for exit.
844 	 */
845 	if ((l->l_pflag & LP_KTRCSW) != 0) {
846 		struct timespec *ts;
847 		l->l_pflag &= ~LP_KTRCSW;
848 
849 		if (ktealloc(&kte, (void *)&kc, l, KTR_CSW, sizeof(*kc)))
850 			return;
851 
852 		kc->out = 1;
853 		kc->user = ((l->l_pflag & LP_KTRCSWUSER) != 0);
854 
855 		ts = &l->l_ktrcsw;
856 		switch (KTRFAC_VERSION(p->p_traceflag)) {
857 		case 0:
858 			kte->kte_kth.ktr_otv.tv_sec = ts->tv_sec;
859 			kte->kte_kth.ktr_otv.tv_usec = ts->tv_nsec / 1000;
860 			break;
861 		case 1:
862 			kte->kte_kth.ktr_ots.tv_sec = ts->tv_sec;
863 			kte->kte_kth.ktr_ots.tv_nsec = ts->tv_nsec;
864 			break;
865 		case 2:
866 			kte->kte_kth.ktr_ts.tv_sec = ts->tv_sec;
867 			kte->kte_kth.ktr_ts.tv_nsec = ts->tv_nsec;
868 			break;
869 		default:
870 			break;
871 		}
872 
873 		ktraddentry(l, kte, KTA_WAITOK);
874 	}
875 
876 	if (ktealloc(&kte, (void *)&kc, l, KTR_CSW, sizeof(*kc)))
877 		return;
878 
879 	kc->out = 0;
880 	kc->user = user;
881 
882 	ktraddentry(l, kte, KTA_WAITOK);
883 }
884 
885 bool
886 ktr_point(int fac_bit)
887 {
888 	return curlwp->l_proc->p_traceflag & fac_bit;
889 }
890 
891 int
892 ktruser(const char *id, void *addr, size_t len, int ustr)
893 {
894 	struct ktrace_entry *kte;
895 	struct ktr_user *ktp;
896 	lwp_t *l = curlwp;
897 	void *user_dta;
898 	int error;
899 
900 	if (!KTRPOINT(l->l_proc, KTR_USER))
901 		return 0;
902 
903 	if (len > KTR_USER_MAXLEN)
904 		return ENOSPC;
905 
906 	error = ktealloc(&kte, (void *)&ktp, l, KTR_USER, sizeof(*ktp) + len);
907 	if (error != 0)
908 		return error;
909 
910 	if (ustr) {
911 		if (copyinstr(id, ktp->ktr_id, KTR_USER_MAXIDLEN, NULL) != 0)
912 			ktp->ktr_id[0] = '\0';
913 	} else
914 		strncpy(ktp->ktr_id, id, KTR_USER_MAXIDLEN);
915 	ktp->ktr_id[KTR_USER_MAXIDLEN-1] = '\0';
916 
917 	user_dta = (void *)(ktp + 1);
918 	if ((error = copyin(addr, (void *)user_dta, len)) != 0)
919 		len = 0;
920 
921 	ktraddentry(l, kte, KTA_WAITOK);
922 	return error;
923 }
924 
925 void
926 ktr_kuser(const char *id, void *addr, size_t len)
927 {
928 	struct ktrace_entry *kte;
929 	struct ktr_user *ktp;
930 	lwp_t *l = curlwp;
931 	int error;
932 
933 	if (!KTRPOINT(l->l_proc, KTR_USER))
934 		return;
935 
936 	if (len > KTR_USER_MAXLEN)
937 		return;
938 
939 	error = ktealloc(&kte, (void *)&ktp, l, KTR_USER, sizeof(*ktp) + len);
940 	if (error != 0)
941 		return;
942 
943 	strlcpy(ktp->ktr_id, id, KTR_USER_MAXIDLEN);
944 
945 	memcpy(ktp + 1, addr, len);
946 
947 	ktraddentry(l, kte, KTA_WAITOK);
948 }
949 
950 void
951 ktr_mmsg(const void *msgh, size_t size)
952 {
953 	lwp_t *l = curlwp;
954 
955 	if (!KTRPOINT(l->l_proc, KTR_MMSG))
956 		return;
957 
958 	ktr_kmem(l, KTR_MMSG, msgh, size);
959 }
960 
961 void
962 ktr_mool(const void *kaddr, size_t size, const void *uaddr)
963 {
964 	struct ktrace_entry *kte;
965 	struct ktr_mool *kp;
966 	struct ktr_mool *bf;
967 	lwp_t *l = curlwp;
968 
969 	if (!KTRPOINT(l->l_proc, KTR_MOOL))
970 		return;
971 
972 	if (ktealloc(&kte, (void *)&kp, l, KTR_MOOL, size + sizeof(*kp)))
973 		return;
974 
975 	kp->uaddr = uaddr;
976 	kp->size = size;
977 	bf = kp + 1; /* Skip uaddr and size */
978 	(void)memcpy(bf, kaddr, size);
979 
980 	ktraddentry(l, kte, KTA_WAITOK);
981 }
982 
983 void
984 ktr_saupcall(struct lwp *l, int type, int nevent, int nint, void *sas,
985     void *ap, void *ksas)
986 {
987 	struct ktrace_entry *kte;
988 	struct ktr_saupcall *ktp;
989 	size_t len, sz;
990 	struct sa_t **sapp;
991 	int i;
992 
993 	if (!KTRPOINT(l->l_proc, KTR_SAUPCALL))
994 		return;
995 
996 	len = sizeof(struct ktr_saupcall);
997 	sz = len + sizeof(struct sa_t) * (nevent + nint + 1);
998 
999 	if (ktealloc(&kte, (void *)&ktp, l, KTR_SAUPCALL, sz))
1000 		return;
1001 
1002 	ktp->ktr_type = type;
1003 	ktp->ktr_nevent = nevent;
1004 	ktp->ktr_nint = nint;
1005 	ktp->ktr_sas = sas;
1006 	ktp->ktr_ap = ap;
1007 
1008 	/* Copy the sa_t's */
1009 	sapp = (struct sa_t **) ksas;
1010 
1011 	for (i = nevent + nint; i >= 0; i--) {
1012 		memcpy((char *)ktp + len, *sapp, sizeof(struct sa_t));
1013 		len += sizeof(struct sa_t);
1014 		sapp++;
1015 	}
1016 
1017 	kte->kte_kth.ktr_len = len;
1018 	ktraddentry(l, kte, KTA_WAITOK);
1019 }
1020 
1021 void
1022 ktr_mib(const int *name, u_int namelen)
1023 {
1024 	struct ktrace_entry *kte;
1025 	int *namep;
1026 	size_t size;
1027 	lwp_t *l = curlwp;
1028 
1029 	if (!KTRPOINT(l->l_proc, KTR_MIB))
1030 		return;
1031 
1032 	size = namelen * sizeof(*name);
1033 
1034 	if (ktealloc(&kte, (void *)&namep, l, KTR_MIB, size))
1035 		return;
1036 
1037 	(void)memcpy(namep, name, namelen * sizeof(*name));
1038 
1039 	ktraddentry(l, kte, KTA_WAITOK);
1040 }
1041 
1042 /* Interface and common routines */
1043 
1044 int
1045 ktrace_common(lwp_t *curl, int ops, int facs, int pid, file_t *fp)
1046 {
1047 	struct proc *curp;
1048 	struct proc *p;
1049 	struct pgrp *pg;
1050 	struct ktr_desc *ktd = NULL;
1051 	int ret = 0;
1052 	int error = 0;
1053 	int descend;
1054 
1055 	curp = curl->l_proc;
1056 	descend = ops & KTRFLAG_DESCEND;
1057 	facs = facs & ~((unsigned) KTRFAC_PERSISTENT);
1058 
1059 	(void)ktrenter(curl);
1060 
1061 	switch (KTROP(ops)) {
1062 
1063 	case KTROP_CLEARFILE:
1064 		/*
1065 		 * Clear all uses of the tracefile
1066 		 */
1067 		mutex_enter(&ktrace_lock);
1068 		ktd = ktd_lookup(fp);
1069 		mutex_exit(&ktrace_lock);
1070 		if (ktd == NULL)
1071 			goto done;
1072 		error = ktrderefall(ktd, 1);
1073 		goto done;
1074 
1075 	case KTROP_SET:
1076 		mutex_enter(&ktrace_lock);
1077 		ktd = ktd_lookup(fp);
1078 		mutex_exit(&ktrace_lock);
1079 		if (ktd == NULL) {
1080 			ktd = kmem_alloc(sizeof(*ktd), KM_SLEEP);
1081 			TAILQ_INIT(&ktd->ktd_queue);
1082 			callout_init(&ktd->ktd_wakch, CALLOUT_MPSAFE);
1083 			cv_init(&ktd->ktd_cv, "ktrwait");
1084 			cv_init(&ktd->ktd_sync_cv, "ktrsync");
1085 			ktd->ktd_flags = 0;
1086 			ktd->ktd_qcount = 0;
1087 			ktd->ktd_error = 0;
1088 			ktd->ktd_errcnt = 0;
1089 			ktd->ktd_delayqcnt = ktd_delayqcnt;
1090 			ktd->ktd_wakedelay = mstohz(ktd_wakedelay);
1091 			ktd->ktd_intrwakdl = mstohz(ktd_intrwakdl);
1092 			ktd->ktd_ref = 0;
1093 			ktd->ktd_fp = fp;
1094 			mutex_enter(&ktrace_lock);
1095 			ktdref(ktd);
1096 			mutex_exit(&ktrace_lock);
1097 
1098 			/*
1099 			 * XXX: not correct.  needs an way to detect
1100 			 * whether ktruss or ktrace.
1101 			 */
1102 			if (fp->f_type == DTYPE_PIPE)
1103 				ktd->ktd_flags |= KTDF_INTERACTIVE;
1104 
1105 			mutex_enter(&fp->f_lock);
1106 			fp->f_count++;
1107 			mutex_exit(&fp->f_lock);
1108 			error = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL,
1109 			    ktrace_thread, ktd, &ktd->ktd_lwp, "ktrace");
1110 			if (error != 0) {
1111 				kmem_free(ktd, sizeof(*ktd));
1112 				mutex_enter(&fp->f_lock);
1113 				fp->f_count--;
1114 				mutex_exit(&fp->f_lock);
1115 				goto done;
1116 			}
1117 
1118 			mutex_enter(&ktrace_lock);
1119 			if (ktd_lookup(fp) != NULL) {
1120 				ktdrel(ktd);
1121 				ktd = NULL;
1122 			} else
1123 				TAILQ_INSERT_TAIL(&ktdq, ktd, ktd_list);
1124 			if (ktd == NULL)
1125 				cv_wait(&lbolt, &ktrace_lock);
1126 			mutex_exit(&ktrace_lock);
1127 			if (ktd == NULL)
1128 				goto done;
1129 		}
1130 		break;
1131 
1132 	case KTROP_CLEAR:
1133 		break;
1134 	}
1135 
1136 	/*
1137 	 * need something to (un)trace (XXX - why is this here?)
1138 	 */
1139 	if (!facs) {
1140 		error = EINVAL;
1141 		goto done;
1142 	}
1143 
1144 	/*
1145 	 * do it
1146 	 */
1147 	mutex_enter(proc_lock);
1148 	if (pid < 0) {
1149 		/*
1150 		 * by process group
1151 		 */
1152 		pg = pg_find(-pid, PFIND_LOCKED);
1153 		if (pg == NULL)
1154 			error = ESRCH;
1155 		else {
1156 			LIST_FOREACH(p, &pg->pg_members, p_pglist) {
1157 				if (descend)
1158 					ret |= ktrsetchildren(curl, p, ops,
1159 					    facs, ktd);
1160 				else
1161 					ret |= ktrops(curl, p, ops, facs,
1162 					    ktd);
1163 			}
1164 		}
1165 
1166 	} else {
1167 		/*
1168 		 * by pid
1169 		 */
1170 		p = p_find(pid, PFIND_LOCKED);
1171 		if (p == NULL)
1172 			error = ESRCH;
1173 		else if (descend)
1174 			ret |= ktrsetchildren(curl, p, ops, facs, ktd);
1175 		else
1176 			ret |= ktrops(curl, p, ops, facs, ktd);
1177 	}
1178 	mutex_exit(proc_lock);
1179 	if (error == 0 && !ret)
1180 		error = EPERM;
1181 done:
1182 	if (ktd != NULL) {
1183 		mutex_enter(&ktrace_lock);
1184 		if (error != 0) {
1185 			/*
1186 			 * Wakeup the thread so that it can be die if we
1187 			 * can't trace any process.
1188 			 */
1189 			ktd_wakeup(ktd);
1190 		}
1191 		if (KTROP(ops) == KTROP_SET || KTROP(ops) == KTROP_CLEARFILE)
1192 			ktdrel(ktd);
1193 		mutex_exit(&ktrace_lock);
1194 	}
1195 	ktrexit(curl);
1196 	return (error);
1197 }
1198 
1199 /*
1200  * fktrace system call
1201  */
1202 /* ARGSUSED */
1203 int
1204 sys_fktrace(struct lwp *l, const struct sys_fktrace_args *uap, register_t *retval)
1205 {
1206 	/* {
1207 		syscallarg(int) fd;
1208 		syscallarg(int) ops;
1209 		syscallarg(int) facs;
1210 		syscallarg(int) pid;
1211 	} */
1212 	file_t *fp;
1213 	int error, fd;
1214 
1215 	fd = SCARG(uap, fd);
1216 	if ((fp = fd_getfile(fd)) == NULL)
1217 		return (EBADF);
1218 	if ((fp->f_flag & FWRITE) == 0)
1219 		error = EBADF;
1220 	else
1221 		error = ktrace_common(l, SCARG(uap, ops),
1222 		    SCARG(uap, facs), SCARG(uap, pid), fp);
1223 	fd_putfile(fd);
1224 	return error;
1225 }
1226 
1227 /*
1228  * ktrace system call
1229  */
1230 /* ARGSUSED */
1231 int
1232 sys_ktrace(struct lwp *l, const struct sys_ktrace_args *uap, register_t *retval)
1233 {
1234 	/* {
1235 		syscallarg(const char *) fname;
1236 		syscallarg(int) ops;
1237 		syscallarg(int) facs;
1238 		syscallarg(int) pid;
1239 	} */
1240 	struct vnode *vp = NULL;
1241 	file_t *fp = NULL;
1242 	struct nameidata nd;
1243 	int error = 0;
1244 	int fd;
1245 
1246 	if (ktrenter(l))
1247 		return EAGAIN;
1248 
1249 	if (KTROP(SCARG(uap, ops)) != KTROP_CLEAR) {
1250 		/*
1251 		 * an operation which requires a file argument.
1252 		 */
1253 		NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, fname));
1254 		if ((error = vn_open(&nd, FREAD|FWRITE, 0)) != 0) {
1255 			ktrexit(l);
1256 			return (error);
1257 		}
1258 		vp = nd.ni_vp;
1259 		VOP_UNLOCK(vp, 0);
1260 		if (vp->v_type != VREG) {
1261 			vn_close(vp, FREAD|FWRITE, l->l_cred);
1262 			ktrexit(l);
1263 			return (EACCES);
1264 		}
1265 		/*
1266 		 * This uses up a file descriptor slot in the
1267 		 * tracing process for the duration of this syscall.
1268 		 * This is not expected to be a problem.
1269 		 */
1270 		if ((error = fd_allocfile(&fp, &fd)) != 0) {
1271 			vn_close(vp, FWRITE, l->l_cred);
1272 			ktrexit(l);
1273 			return error;
1274 		}
1275 		fp->f_flag = FWRITE;
1276 		fp->f_type = DTYPE_VNODE;
1277 		fp->f_ops = &vnops;
1278 		fp->f_data = (void *)vp;
1279 		vp = NULL;
1280 	}
1281 	error = ktrace_common(l, SCARG(uap, ops), SCARG(uap, facs),
1282 	    SCARG(uap, pid), fp);
1283 	if (fp != NULL) {
1284 		if (error != 0) {
1285 			/* File unused. */
1286 			fd_abort(curproc, fp, fd);
1287 		} else {
1288 			/* File was used. */
1289 			fd_abort(curproc, NULL, fd);
1290 		}
1291 	}
1292 	return (error);
1293 }
1294 
1295 int
1296 ktrops(lwp_t *curl, struct proc *p, int ops, int facs,
1297     struct ktr_desc *ktd)
1298 {
1299 	int vers = ops & KTRFAC_VER_MASK;
1300 	int error = 0;
1301 
1302 	mutex_enter(p->p_lock);
1303 	mutex_enter(&ktrace_lock);
1304 
1305 	if (!ktrcanset(curl, p))
1306 		goto out;
1307 
1308 	switch (vers) {
1309 	case KTRFACv0:
1310 	case KTRFACv1:
1311 	case KTRFACv2:
1312 		break;
1313 	default:
1314 		error = EINVAL;
1315 		goto out;
1316 	}
1317 
1318 	if (KTROP(ops) == KTROP_SET) {
1319 		if (p->p_tracep != ktd) {
1320 			/*
1321 			 * if trace file already in use, relinquish
1322 			 */
1323 			ktrderef(p);
1324 			p->p_tracep = ktd;
1325 			ktradref(p);
1326 		}
1327 		p->p_traceflag |= facs;
1328 		if (kauth_authorize_process(curl->l_cred, KAUTH_PROCESS_KTRACE,
1329 		    p, KAUTH_ARG(KAUTH_REQ_PROCESS_KTRACE_PERSISTENT), NULL,
1330 		    NULL) == 0)
1331 			p->p_traceflag |= KTRFAC_PERSISTENT;
1332 	} else {
1333 		/* KTROP_CLEAR */
1334 		if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
1335 			/* no more tracing */
1336 			ktrderef(p);
1337 		}
1338 	}
1339 
1340 	if (p->p_traceflag)
1341 		p->p_traceflag |= vers;
1342 	/*
1343 	 * Emit an emulation record, every time there is a ktrace
1344 	 * change/attach request.
1345 	 */
1346 	if (KTRPOINT(p, KTR_EMUL))
1347 		p->p_traceflag |= KTRFAC_TRC_EMUL;
1348 
1349 	p->p_trace_enabled = trace_is_enabled(p);
1350 #ifdef __HAVE_SYSCALL_INTERN
1351 	(*p->p_emul->e_syscall_intern)(p);
1352 #endif
1353 
1354  out:
1355  	mutex_exit(&ktrace_lock);
1356  	mutex_exit(p->p_lock);
1357 
1358 	return (1);
1359 }
1360 
1361 int
1362 ktrsetchildren(lwp_t *curl, struct proc *top, int ops, int facs,
1363     struct ktr_desc *ktd)
1364 {
1365 	struct proc *p;
1366 	int ret = 0;
1367 
1368 	KASSERT(mutex_owned(proc_lock));
1369 
1370 	p = top;
1371 	for (;;) {
1372 		ret |= ktrops(curl, p, ops, facs, ktd);
1373 		/*
1374 		 * If this process has children, descend to them next,
1375 		 * otherwise do any siblings, and if done with this level,
1376 		 * follow back up the tree (but not past top).
1377 		 */
1378 		if (LIST_FIRST(&p->p_children) != NULL) {
1379 			p = LIST_FIRST(&p->p_children);
1380 			continue;
1381 		}
1382 		for (;;) {
1383 			if (p == top)
1384 				return (ret);
1385 			if (LIST_NEXT(p, p_sibling) != NULL) {
1386 				p = LIST_NEXT(p, p_sibling);
1387 				break;
1388 			}
1389 			p = p->p_pptr;
1390 		}
1391 	}
1392 	/*NOTREACHED*/
1393 }
1394 
1395 void
1396 ktrwrite(struct ktr_desc *ktd, struct ktrace_entry *kte)
1397 {
1398 	size_t hlen;
1399 	struct uio auio;
1400 	struct iovec aiov[64], *iov;
1401 	struct ktrace_entry *top = kte;
1402 	struct ktr_header *kth;
1403 	file_t *fp = ktd->ktd_fp;
1404 	int error;
1405 next:
1406 	auio.uio_iov = iov = &aiov[0];
1407 	auio.uio_offset = 0;
1408 	auio.uio_rw = UIO_WRITE;
1409 	auio.uio_resid = 0;
1410 	auio.uio_iovcnt = 0;
1411 	UIO_SETUP_SYSSPACE(&auio);
1412 	do {
1413 		struct timespec ts;
1414 		lwpid_t lid;
1415 		kth = &kte->kte_kth;
1416 
1417 		hlen = sizeof(struct ktr_header);
1418 		switch (kth->ktr_version) {
1419 		case 0:
1420 			ts = kth->ktr_time;
1421 
1422 			kth->ktr_otv.tv_sec = ts.tv_sec;
1423 			kth->ktr_otv.tv_usec = ts.tv_nsec / 1000;
1424 			kth->ktr_unused = NULL;
1425 			hlen -= sizeof(kth->_v) -
1426 			    MAX(sizeof(kth->_v._v0), sizeof(kth->_v._v1));
1427 			break;
1428 		case 1:
1429 			ts = kth->ktr_time;
1430 			lid = kth->ktr_lid;
1431 
1432 			kth->ktr_ots.tv_sec = ts.tv_sec;
1433 			kth->ktr_ots.tv_nsec = ts.tv_nsec;
1434 			kth->ktr_olid = lid;
1435 			hlen -= sizeof(kth->_v) -
1436 			    MAX(sizeof(kth->_v._v0), sizeof(kth->_v._v1));
1437 			break;
1438 		}
1439 		iov->iov_base = (void *)kth;
1440 		iov++->iov_len = hlen;
1441 		auio.uio_resid += hlen;
1442 		auio.uio_iovcnt++;
1443 		if (kth->ktr_len > 0) {
1444 			iov->iov_base = kte->kte_buf;
1445 			iov++->iov_len = kth->ktr_len;
1446 			auio.uio_resid += kth->ktr_len;
1447 			auio.uio_iovcnt++;
1448 		}
1449 	} while ((kte = TAILQ_NEXT(kte, kte_list)) != NULL &&
1450 	    auio.uio_iovcnt < sizeof(aiov) / sizeof(aiov[0]) - 1);
1451 
1452 again:
1453 	error = (*fp->f_ops->fo_write)(fp, &fp->f_offset, &auio,
1454 	    fp->f_cred, FOF_UPDATE_OFFSET);
1455 	switch (error) {
1456 
1457 	case 0:
1458 		if (auio.uio_resid > 0)
1459 			goto again;
1460 		if (kte != NULL)
1461 			goto next;
1462 		break;
1463 
1464 	case EWOULDBLOCK:
1465 		kpause("ktrzzz", false, 1, NULL);
1466 		goto again;
1467 
1468 	default:
1469 		/*
1470 		 * If error encountered, give up tracing on this
1471 		 * vnode.  Don't report EPIPE as this can easily
1472 		 * happen with fktrace()/ktruss.
1473 		 */
1474 #ifndef DEBUG
1475 		if (error != EPIPE)
1476 #endif
1477 			log(LOG_NOTICE,
1478 			    "ktrace write failed, errno %d, tracing stopped\n",
1479 			    error);
1480 		(void)ktrderefall(ktd, 0);
1481 	}
1482 
1483 	while ((kte = top) != NULL) {
1484 		top = TAILQ_NEXT(top, kte_list);
1485 		ktefree(kte);
1486 	}
1487 }
1488 
1489 void
1490 ktrace_thread(void *arg)
1491 {
1492 	struct ktr_desc *ktd = arg;
1493 	file_t *fp = ktd->ktd_fp;
1494 	struct ktrace_entry *kte;
1495 	int ktrerr, errcnt;
1496 
1497 	mutex_enter(&ktrace_lock);
1498 	for (;;) {
1499 		kte = TAILQ_FIRST(&ktd->ktd_queue);
1500 		if (kte == NULL) {
1501 			if (ktd->ktd_flags & KTDF_WAIT) {
1502 				ktd->ktd_flags &= ~(KTDF_WAIT | KTDF_BLOCKING);
1503 				cv_broadcast(&ktd->ktd_sync_cv);
1504 			}
1505 			if (ktd->ktd_ref == 0)
1506 				break;
1507 			cv_wait(&ktd->ktd_cv, &ktrace_lock);
1508 			continue;
1509 		}
1510 		TAILQ_INIT(&ktd->ktd_queue);
1511 		ktd->ktd_qcount = 0;
1512 		ktrerr = ktd->ktd_error;
1513 		errcnt = ktd->ktd_errcnt;
1514 		ktd->ktd_error = ktd->ktd_errcnt = 0;
1515 		mutex_exit(&ktrace_lock);
1516 
1517 		if (ktrerr) {
1518 			log(LOG_NOTICE,
1519 			    "ktrace failed, fp %p, error 0x%x, total %d\n",
1520 			    fp, ktrerr, errcnt);
1521 		}
1522 		ktrwrite(ktd, kte);
1523 		mutex_enter(&ktrace_lock);
1524 	}
1525 
1526 	TAILQ_REMOVE(&ktdq, ktd, ktd_list);
1527 	mutex_exit(&ktrace_lock);
1528 
1529 	/*
1530 	 * ktrace file descriptor can't be watched (are not visible to
1531 	 * userspace), so no kqueue stuff here
1532 	 * XXX: The above comment is wrong, because the fktrace file
1533 	 * descriptor is available in userland.
1534 	 */
1535 	closef(fp);
1536 
1537 	cv_destroy(&ktd->ktd_sync_cv);
1538 	cv_destroy(&ktd->ktd_cv);
1539 
1540 	callout_stop(&ktd->ktd_wakch);
1541 	callout_destroy(&ktd->ktd_wakch);
1542 	kmem_free(ktd, sizeof(*ktd));
1543 
1544 	kthread_exit(0);
1545 }
1546 
1547 /*
1548  * Return true if caller has permission to set the ktracing state
1549  * of target.  Essentially, the target can't possess any
1550  * more permissions than the caller.  KTRFAC_PERSISTENT signifies that
1551  * the tracing will persist on sugid processes during exec; it is only
1552  * settable by a process with appropriate credentials.
1553  *
1554  * TODO: check groups.  use caller effective gid.
1555  */
1556 int
1557 ktrcanset(lwp_t *calll, struct proc *targetp)
1558 {
1559 	KASSERT(mutex_owned(targetp->p_lock));
1560 	KASSERT(mutex_owned(&ktrace_lock));
1561 
1562 	if (kauth_authorize_process(calll->l_cred, KAUTH_PROCESS_KTRACE,
1563 	    targetp, NULL, NULL, NULL) == 0)
1564 		return (1);
1565 
1566 	return (0);
1567 }
1568 
1569 /*
1570  * Put user defined entry to ktrace records.
1571  */
1572 int
1573 sys_utrace(struct lwp *l, const struct sys_utrace_args *uap, register_t *retval)
1574 {
1575 	/* {
1576 		syscallarg(const char *) label;
1577 		syscallarg(void *) addr;
1578 		syscallarg(size_t) len;
1579 	} */
1580 
1581 	return ktruser(SCARG(uap, label), SCARG(uap, addr),
1582 	    SCARG(uap, len), 1);
1583 }
1584