1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1989, 1993
5 * The Regents of the University of California.
6 * Copyright (c) 2005 Robert N. M. Watson
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * @(#)kern_ktrace.c 8.2 (Berkeley) 9/23/93
34 */
35
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38
39 #include "opt_ktrace.h"
40
41 #include <sys/param.h>
42 #include <sys/capsicum.h>
43 #include <sys/systm.h>
44 #include <sys/fcntl.h>
45 #include <sys/kernel.h>
46 #include <sys/kthread.h>
47 #include <sys/lock.h>
48 #include <sys/mutex.h>
49 #include <sys/malloc.h>
50 #include <sys/mount.h>
51 #include <sys/namei.h>
52 #include <sys/priv.h>
53 #include <sys/proc.h>
54 #include <sys/resourcevar.h>
55 #include <sys/unistd.h>
56 #include <sys/vnode.h>
57 #include <sys/socket.h>
58 #include <sys/stat.h>
59 #include <sys/ktrace.h>
60 #include <sys/sx.h>
61 #include <sys/sysctl.h>
62 #include <sys/sysent.h>
63 #include <sys/syslog.h>
64 #include <sys/sysproto.h>
65
66 #include <security/mac/mac_framework.h>
67
68 /*
69 * The ktrace facility allows the tracing of certain key events in user space
70 * processes, such as system calls, signal delivery, context switches, and
71 * user generated events using utrace(2). It works by streaming event
72 * records and data to a vnode associated with the process using the
73 * ktrace(2) system call. In general, records can be written directly from
74 * the context that generates the event. One important exception to this is
75 * during a context switch, where sleeping is not permitted. To handle this
76 * case, trace events are generated using in-kernel ktr_request records, and
77 * then delivered to disk at a convenient moment -- either immediately, the
78 * next traceable event, at system call return, or at process exit.
79 *
80 * When dealing with multiple threads or processes writing to the same event
81 * log, ordering guarantees are weak: specifically, if an event has multiple
82 * records (i.e., system call enter and return), they may be interlaced with
83 * records from another event. Process and thread ID information is provided
84 * in the record, and user applications can de-interlace events if required.
85 */
86
87 static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE");
88
89 #ifdef KTRACE
90
91 FEATURE(ktrace, "Kernel support for system-call tracing");
92
93 #ifndef KTRACE_REQUEST_POOL
94 #define KTRACE_REQUEST_POOL 100
95 #endif
96
97 struct ktr_request {
98 struct ktr_header ktr_header;
99 void *ktr_buffer;
100 union {
101 struct ktr_proc_ctor ktr_proc_ctor;
102 struct ktr_cap_fail ktr_cap_fail;
103 struct ktr_syscall ktr_syscall;
104 struct ktr_sysret ktr_sysret;
105 struct ktr_genio ktr_genio;
106 struct ktr_psig ktr_psig;
107 struct ktr_csw ktr_csw;
108 struct ktr_fault ktr_fault;
109 struct ktr_faultend ktr_faultend;
110 struct ktr_struct_array ktr_struct_array;
111 } ktr_data;
112 STAILQ_ENTRY(ktr_request) ktr_list;
113 };
114
115 static int data_lengths[] = {
116 [KTR_SYSCALL] = offsetof(struct ktr_syscall, ktr_args),
117 [KTR_SYSRET] = sizeof(struct ktr_sysret),
118 [KTR_NAMEI] = 0,
119 [KTR_GENIO] = sizeof(struct ktr_genio),
120 [KTR_PSIG] = sizeof(struct ktr_psig),
121 [KTR_CSW] = sizeof(struct ktr_csw),
122 [KTR_USER] = 0,
123 [KTR_STRUCT] = 0,
124 [KTR_SYSCTL] = 0,
125 [KTR_PROCCTOR] = sizeof(struct ktr_proc_ctor),
126 [KTR_PROCDTOR] = 0,
127 [KTR_CAPFAIL] = sizeof(struct ktr_cap_fail),
128 [KTR_FAULT] = sizeof(struct ktr_fault),
129 [KTR_FAULTEND] = sizeof(struct ktr_faultend),
130 [KTR_STRUCT_ARRAY] = sizeof(struct ktr_struct_array),
131 };
132
133 static STAILQ_HEAD(, ktr_request) ktr_free;
134
135 static SYSCTL_NODE(_kern, OID_AUTO, ktrace, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
136 "KTRACE options");
137
138 static u_int ktr_requestpool = KTRACE_REQUEST_POOL;
139 TUNABLE_INT("kern.ktrace.request_pool", &ktr_requestpool);
140
141 u_int ktr_geniosize = PAGE_SIZE;
142 SYSCTL_UINT(_kern_ktrace, OID_AUTO, genio_size, CTLFLAG_RWTUN, &ktr_geniosize,
143 0, "Maximum size of genio event payload");
144
145 /*
146 * Allow to not to send signal to traced process, in which context the
147 * ktr record is written. The limit is applied from the process that
148 * set up ktrace, so killing the traced process is not completely fair.
149 */
150 int ktr_filesize_limit_signal = 0;
151 SYSCTL_INT(_kern_ktrace, OID_AUTO, filesize_limit_signal, CTLFLAG_RWTUN,
152 &ktr_filesize_limit_signal, 0,
153 "Send SIGXFSZ to the traced process when the log size limit is exceeded");
154
155 static int print_message = 1;
156 static struct mtx ktrace_mtx;
157 static struct sx ktrace_sx;
158
159 struct ktr_io_params {
160 struct vnode *vp;
161 struct ucred *cr;
162 off_t lim;
163 u_int refs;
164 };
165
166 static void ktrace_init(void *dummy);
167 static int sysctl_kern_ktrace_request_pool(SYSCTL_HANDLER_ARGS);
168 static u_int ktrace_resize_pool(u_int oldsize, u_int newsize);
169 static struct ktr_request *ktr_getrequest_entered(struct thread *td, int type);
170 static struct ktr_request *ktr_getrequest(int type);
171 static void ktr_submitrequest(struct thread *td, struct ktr_request *req);
172 static struct ktr_io_params *ktr_freeproc(struct proc *p);
173 static void ktr_freerequest(struct ktr_request *req);
174 static void ktr_freerequest_locked(struct ktr_request *req);
175 static void ktr_writerequest(struct thread *td, struct ktr_request *req);
176 static int ktrcanset(struct thread *,struct proc *);
177 static int ktrsetchildren(struct thread *, struct proc *, int, int,
178 struct ktr_io_params *);
179 static int ktrops(struct thread *, struct proc *, int, int,
180 struct ktr_io_params *);
181 static void ktrprocctor_entered(struct thread *, struct proc *);
182
183 /*
184 * ktrace itself generates events, such as context switches, which we do not
185 * wish to trace. Maintain a flag, TDP_INKTRACE, on each thread to determine
186 * whether or not it is in a region where tracing of events should be
187 * suppressed.
188 */
189 static void
190 ktrace_enter(struct thread *td)
191 {
192
193 KASSERT(!(td->td_pflags & TDP_INKTRACE), ("ktrace_enter: flag set"));
194 td->td_pflags |= TDP_INKTRACE;
195 }
196
197 static void
198 ktrace_exit(struct thread *td)
199 {
200
201 KASSERT(td->td_pflags & TDP_INKTRACE, ("ktrace_exit: flag not set"));
202 td->td_pflags &= ~TDP_INKTRACE;
203 }
204
205 static void
206 ktrace_assert(struct thread *td)
207 {
208
209 KASSERT(td->td_pflags & TDP_INKTRACE, ("ktrace_assert: flag not set"));
210 }
211
212 static void
213 ast_ktrace(struct thread *td, int tda __unused)
214 {
215 KTRUSERRET(td);
216 }
217
218 static void
219 ktrace_init(void *dummy)
220 {
221 struct ktr_request *req;
222 int i;
223
224 mtx_init(&ktrace_mtx, "ktrace", NULL, MTX_DEF | MTX_QUIET);
225 sx_init(&ktrace_sx, "ktrace_sx");
226 STAILQ_INIT(&ktr_free);
227 for (i = 0; i < ktr_requestpool; i++) {
228 req = malloc(sizeof(struct ktr_request), M_KTRACE, M_WAITOK |
229 M_ZERO);
230 STAILQ_INSERT_HEAD(&ktr_free, req, ktr_list);
231 }
232 ast_register(TDA_KTRACE, ASTR_ASTF_REQUIRED, 0, ast_ktrace);
233 }
234 SYSINIT(ktrace_init, SI_SUB_KTRACE, SI_ORDER_ANY, ktrace_init, NULL);
235
236 static int
237 sysctl_kern_ktrace_request_pool(SYSCTL_HANDLER_ARGS)
238 {
239 struct thread *td;
240 u_int newsize, oldsize, wantsize;
241 int error;
242
243 /* Handle easy read-only case first to avoid warnings from GCC. */
244 if (!req->newptr) {
245 oldsize = ktr_requestpool;
246 return (SYSCTL_OUT(req, &oldsize, sizeof(u_int)));
247 }
248
249 error = SYSCTL_IN(req, &wantsize, sizeof(u_int));
250 if (error)
251 return (error);
252 td = curthread;
253 ktrace_enter(td);
254 oldsize = ktr_requestpool;
255 newsize = ktrace_resize_pool(oldsize, wantsize);
256 ktrace_exit(td);
257 error = SYSCTL_OUT(req, &oldsize, sizeof(u_int));
258 if (error)
259 return (error);
260 if (wantsize > oldsize && newsize < wantsize)
261 return (ENOSPC);
262 return (0);
263 }
264 SYSCTL_PROC(_kern_ktrace, OID_AUTO, request_pool,
265 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, &ktr_requestpool, 0,
266 sysctl_kern_ktrace_request_pool, "IU",
267 "Pool buffer size for ktrace(1)");
268
269 static u_int
270 ktrace_resize_pool(u_int oldsize, u_int newsize)
271 {
272 STAILQ_HEAD(, ktr_request) ktr_new;
273 struct ktr_request *req;
274 int bound;
275
276 print_message = 1;
277 bound = newsize - oldsize;
278 if (bound == 0)
279 return (ktr_requestpool);
280 if (bound < 0) {
281 mtx_lock(&ktrace_mtx);
282 /* Shrink pool down to newsize if possible. */
283 while (bound++ < 0) {
284 req = STAILQ_FIRST(&ktr_free);
285 if (req == NULL)
286 break;
287 STAILQ_REMOVE_HEAD(&ktr_free, ktr_list);
288 ktr_requestpool--;
289 free(req, M_KTRACE);
290 }
291 } else {
292 /* Grow pool up to newsize. */
293 STAILQ_INIT(&ktr_new);
294 while (bound-- > 0) {
295 req = malloc(sizeof(struct ktr_request), M_KTRACE,
296 M_WAITOK | M_ZERO);
297 STAILQ_INSERT_HEAD(&ktr_new, req, ktr_list);
298 }
299 mtx_lock(&ktrace_mtx);
300 STAILQ_CONCAT(&ktr_free, &ktr_new);
301 ktr_requestpool += (newsize - oldsize);
302 }
303 mtx_unlock(&ktrace_mtx);
304 return (ktr_requestpool);
305 }
306
307 /* ktr_getrequest() assumes that ktr_comm[] is the same size as td_name[]. */
308 CTASSERT(sizeof(((struct ktr_header *)NULL)->ktr_comm) ==
309 (sizeof((struct thread *)NULL)->td_name));
310
311 static struct ktr_request *
312 ktr_getrequest_entered(struct thread *td, int type)
313 {
314 struct ktr_request *req;
315 struct proc *p = td->td_proc;
316 int pm;
317
318 mtx_lock(&ktrace_mtx);
319 if (!KTRCHECK(td, type)) {
320 mtx_unlock(&ktrace_mtx);
321 return (NULL);
322 }
323 req = STAILQ_FIRST(&ktr_free);
324 if (req != NULL) {
325 STAILQ_REMOVE_HEAD(&ktr_free, ktr_list);
326 req->ktr_header.ktr_type = type;
327 if (p->p_traceflag & KTRFAC_DROP) {
328 req->ktr_header.ktr_type |= KTR_DROP;
329 p->p_traceflag &= ~KTRFAC_DROP;
330 }
331 mtx_unlock(&ktrace_mtx);
332 nanotime(&req->ktr_header.ktr_time);
333 req->ktr_header.ktr_type |= KTR_VERSIONED;
334 req->ktr_header.ktr_pid = p->p_pid;
335 req->ktr_header.ktr_tid = td->td_tid;
336 req->ktr_header.ktr_cpu = PCPU_GET(cpuid);
337 req->ktr_header.ktr_version = KTR_VERSION1;
338 bcopy(td->td_name, req->ktr_header.ktr_comm,
339 sizeof(req->ktr_header.ktr_comm));
340 req->ktr_buffer = NULL;
341 req->ktr_header.ktr_len = 0;
342 } else {
343 p->p_traceflag |= KTRFAC_DROP;
344 pm = print_message;
345 print_message = 0;
346 mtx_unlock(&ktrace_mtx);
347 if (pm)
348 printf("Out of ktrace request objects.\n");
349 }
350 return (req);
351 }
352
353 static struct ktr_request *
354 ktr_getrequest(int type)
355 {
356 struct thread *td = curthread;
357 struct ktr_request *req;
358
359 ktrace_enter(td);
360 req = ktr_getrequest_entered(td, type);
361 if (req == NULL)
362 ktrace_exit(td);
363
364 return (req);
365 }
366
367 /*
368 * Some trace generation environments don't permit direct access to VFS,
369 * such as during a context switch where sleeping is not allowed. Under these
370 * circumstances, queue a request to the thread to be written asynchronously
371 * later.
372 */
373 static void
374 ktr_enqueuerequest(struct thread *td, struct ktr_request *req)
375 {
376
377 mtx_lock(&ktrace_mtx);
378 STAILQ_INSERT_TAIL(&td->td_proc->p_ktr, req, ktr_list);
379 mtx_unlock(&ktrace_mtx);
380 ast_sched(td, TDA_KTRACE);
381 }
382
383 /*
384 * Drain any pending ktrace records from the per-thread queue to disk. This
385 * is used both internally before committing other records, and also on
386 * system call return. We drain all the ones we can find at the time when
387 * drain is requested, but don't keep draining after that as those events
388 * may be approximately "after" the current event.
389 */
390 static void
391 ktr_drain(struct thread *td)
392 {
393 struct ktr_request *queued_req;
394 STAILQ_HEAD(, ktr_request) local_queue;
395
396 ktrace_assert(td);
397 sx_assert(&ktrace_sx, SX_XLOCKED);
398
399 STAILQ_INIT(&local_queue);
400
401 if (!STAILQ_EMPTY(&td->td_proc->p_ktr)) {
402 mtx_lock(&ktrace_mtx);
403 STAILQ_CONCAT(&local_queue, &td->td_proc->p_ktr);
404 mtx_unlock(&ktrace_mtx);
405
406 while ((queued_req = STAILQ_FIRST(&local_queue))) {
407 STAILQ_REMOVE_HEAD(&local_queue, ktr_list);
408 ktr_writerequest(td, queued_req);
409 ktr_freerequest(queued_req);
410 }
411 }
412 }
413
414 /*
415 * Submit a trace record for immediate commit to disk -- to be used only
416 * where entering VFS is OK. First drain any pending records that may have
417 * been cached in the thread.
418 */
419 static void
420 ktr_submitrequest(struct thread *td, struct ktr_request *req)
421 {
422
423 ktrace_assert(td);
424
425 sx_xlock(&ktrace_sx);
426 ktr_drain(td);
427 ktr_writerequest(td, req);
428 ktr_freerequest(req);
429 sx_xunlock(&ktrace_sx);
430 ktrace_exit(td);
431 }
432
433 static void
434 ktr_freerequest(struct ktr_request *req)
435 {
436
437 mtx_lock(&ktrace_mtx);
438 ktr_freerequest_locked(req);
439 mtx_unlock(&ktrace_mtx);
440 }
441
442 static void
443 ktr_freerequest_locked(struct ktr_request *req)
444 {
445
446 mtx_assert(&ktrace_mtx, MA_OWNED);
447 if (req->ktr_buffer != NULL)
448 free(req->ktr_buffer, M_KTRACE);
449 STAILQ_INSERT_HEAD(&ktr_free, req, ktr_list);
450 }
451
452 static void
453 ktr_io_params_ref(struct ktr_io_params *kiop)
454 {
455 mtx_assert(&ktrace_mtx, MA_OWNED);
456 kiop->refs++;
457 }
458
459 static struct ktr_io_params *
460 ktr_io_params_rele(struct ktr_io_params *kiop)
461 {
462 mtx_assert(&ktrace_mtx, MA_OWNED);
463 if (kiop == NULL)
464 return (NULL);
465 KASSERT(kiop->refs > 0, ("kiop ref == 0 %p", kiop));
466 return (--(kiop->refs) == 0 ? kiop : NULL);
467 }
468
469 void
470 ktr_io_params_free(struct ktr_io_params *kiop)
471 {
472 if (kiop == NULL)
473 return;
474
475 MPASS(kiop->refs == 0);
476 vn_close(kiop->vp, FWRITE, kiop->cr, curthread);
477 crfree(kiop->cr);
478 free(kiop, M_KTRACE);
479 }
480
481 static struct ktr_io_params *
482 ktr_io_params_alloc(struct thread *td, struct vnode *vp)
483 {
484 struct ktr_io_params *res;
485
486 res = malloc(sizeof(struct ktr_io_params), M_KTRACE, M_WAITOK);
487 res->vp = vp;
488 res->cr = crhold(td->td_ucred);
489 res->lim = lim_cur(td, RLIMIT_FSIZE);
490 res->refs = 1;
491 return (res);
492 }
493
494 /*
495 * Disable tracing for a process and release all associated resources.
496 * The caller is responsible for releasing a reference on the returned
497 * vnode and credentials.
498 */
499 static struct ktr_io_params *
500 ktr_freeproc(struct proc *p)
501 {
502 struct ktr_io_params *kiop;
503 struct ktr_request *req;
504
505 PROC_LOCK_ASSERT(p, MA_OWNED);
506 mtx_assert(&ktrace_mtx, MA_OWNED);
507 kiop = ktr_io_params_rele(p->p_ktrioparms);
508 p->p_ktrioparms = NULL;
509 p->p_traceflag = 0;
510 while ((req = STAILQ_FIRST(&p->p_ktr)) != NULL) {
511 STAILQ_REMOVE_HEAD(&p->p_ktr, ktr_list);
512 ktr_freerequest_locked(req);
513 }
514 return (kiop);
515 }
516
517 struct vnode *
518 ktr_get_tracevp(struct proc *p, bool ref)
519 {
520 struct vnode *vp;
521
522 PROC_LOCK_ASSERT(p, MA_OWNED);
523
524 if (p->p_ktrioparms != NULL) {
525 vp = p->p_ktrioparms->vp;
526 if (ref)
527 vrefact(vp);
528 } else {
529 vp = NULL;
530 }
531 return (vp);
532 }
533
534 void
535 ktrsyscall(int code, int narg, syscallarg_t args[])
536 {
537 struct ktr_request *req;
538 struct ktr_syscall *ktp;
539 size_t buflen;
540 char *buf = NULL;
541
542 if (__predict_false(curthread->td_pflags & TDP_INKTRACE))
543 return;
544
545 buflen = sizeof(register_t) * narg;
546 if (buflen > 0) {
547 buf = malloc(buflen, M_KTRACE, M_WAITOK);
548 bcopy(args, buf, buflen);
549 }
550 req = ktr_getrequest(KTR_SYSCALL);
551 if (req == NULL) {
552 if (buf != NULL)
553 free(buf, M_KTRACE);
554 return;
555 }
556 ktp = &req->ktr_data.ktr_syscall;
557 ktp->ktr_code = code;
558 ktp->ktr_narg = narg;
559 if (buflen > 0) {
560 req->ktr_header.ktr_len = buflen;
561 req->ktr_buffer = buf;
562 }
563 ktr_submitrequest(curthread, req);
564 }
565
566 void
567 ktrsysret(int code, int error, register_t retval)
568 {
569 struct ktr_request *req;
570 struct ktr_sysret *ktp;
571
572 if (__predict_false(curthread->td_pflags & TDP_INKTRACE))
573 return;
574
575 req = ktr_getrequest(KTR_SYSRET);
576 if (req == NULL)
577 return;
578 ktp = &req->ktr_data.ktr_sysret;
579 ktp->ktr_code = code;
580 ktp->ktr_error = error;
581 ktp->ktr_retval = ((error == 0) ? retval: 0); /* what about val2 ? */
582 ktr_submitrequest(curthread, req);
583 }
584
585 /*
586 * When a setuid process execs, disable tracing.
587 *
588 * XXX: We toss any pending asynchronous records.
589 */
590 struct ktr_io_params *
591 ktrprocexec(struct proc *p)
592 {
593 struct ktr_io_params *kiop;
594
595 PROC_LOCK_ASSERT(p, MA_OWNED);
596
597 kiop = p->p_ktrioparms;
598 if (kiop == NULL || priv_check_cred(kiop->cr, PRIV_DEBUG_DIFFCRED))
599 return (NULL);
600
601 mtx_lock(&ktrace_mtx);
602 kiop = ktr_freeproc(p);
603 mtx_unlock(&ktrace_mtx);
604 return (kiop);
605 }
606
607 /*
608 * When a process exits, drain per-process asynchronous trace records
609 * and disable tracing.
610 */
611 void
612 ktrprocexit(struct thread *td)
613 {
614 struct ktr_request *req;
615 struct proc *p;
616 struct ktr_io_params *kiop;
617
618 p = td->td_proc;
619 if (p->p_traceflag == 0)
620 return;
621
622 ktrace_enter(td);
623 req = ktr_getrequest_entered(td, KTR_PROCDTOR);
624 if (req != NULL)
625 ktr_enqueuerequest(td, req);
626 sx_xlock(&ktrace_sx);
627 ktr_drain(td);
628 sx_xunlock(&ktrace_sx);
629 PROC_LOCK(p);
630 mtx_lock(&ktrace_mtx);
631 kiop = ktr_freeproc(p);
632 mtx_unlock(&ktrace_mtx);
633 PROC_UNLOCK(p);
634 ktr_io_params_free(kiop);
635 ktrace_exit(td);
636 }
637
638 static void
639 ktrprocctor_entered(struct thread *td, struct proc *p)
640 {
641 struct ktr_proc_ctor *ktp;
642 struct ktr_request *req;
643 struct thread *td2;
644
645 ktrace_assert(td);
646 td2 = FIRST_THREAD_IN_PROC(p);
647 req = ktr_getrequest_entered(td2, KTR_PROCCTOR);
648 if (req == NULL)
649 return;
650 ktp = &req->ktr_data.ktr_proc_ctor;
651 ktp->sv_flags = p->p_sysent->sv_flags;
652 ktr_enqueuerequest(td2, req);
653 }
654
655 void
656 ktrprocctor(struct proc *p)
657 {
658 struct thread *td = curthread;
659
660 if ((p->p_traceflag & KTRFAC_MASK) == 0)
661 return;
662
663 ktrace_enter(td);
664 ktrprocctor_entered(td, p);
665 ktrace_exit(td);
666 }
667
668 /*
669 * When a process forks, enable tracing in the new process if needed.
670 */
671 void
672 ktrprocfork(struct proc *p1, struct proc *p2)
673 {
674
675 MPASS(p2->p_ktrioparms == NULL);
676 MPASS(p2->p_traceflag == 0);
677
678 if (p1->p_traceflag == 0)
679 return;
680
681 PROC_LOCK(p1);
682 mtx_lock(&ktrace_mtx);
683 if (p1->p_traceflag & KTRFAC_INHERIT) {
684 p2->p_traceflag = p1->p_traceflag;
685 if ((p2->p_ktrioparms = p1->p_ktrioparms) != NULL)
686 p1->p_ktrioparms->refs++;
687 }
688 mtx_unlock(&ktrace_mtx);
689 PROC_UNLOCK(p1);
690
691 ktrprocctor(p2);
692 }
693
694 /*
695 * When a thread returns, drain any asynchronous records generated by the
696 * system call.
697 */
698 void
699 ktruserret(struct thread *td)
700 {
701
702 ktrace_enter(td);
703 sx_xlock(&ktrace_sx);
704 ktr_drain(td);
705 sx_xunlock(&ktrace_sx);
706 ktrace_exit(td);
707 }
708
709 void
710 ktrnamei(const char *path)
711 {
712 struct ktr_request *req;
713 int namelen;
714 char *buf = NULL;
715
716 namelen = strlen(path);
717 if (namelen > 0) {
718 buf = malloc(namelen, M_KTRACE, M_WAITOK);
719 bcopy(path, buf, namelen);
720 }
721 req = ktr_getrequest(KTR_NAMEI);
722 if (req == NULL) {
723 if (buf != NULL)
724 free(buf, M_KTRACE);
725 return;
726 }
727 if (namelen > 0) {
728 req->ktr_header.ktr_len = namelen;
729 req->ktr_buffer = buf;
730 }
731 ktr_submitrequest(curthread, req);
732 }
733
734 void
735 ktrsysctl(int *name, u_int namelen)
736 {
737 struct ktr_request *req;
738 u_int mib[CTL_MAXNAME + 2];
739 char *mibname;
740 size_t mibnamelen;
741 int error;
742
743 /* Lookup name of mib. */
744 KASSERT(namelen <= CTL_MAXNAME, ("sysctl MIB too long"));
745 mib[0] = 0;
746 mib[1] = 1;
747 bcopy(name, mib + 2, namelen * sizeof(*name));
748 mibnamelen = 128;
749 mibname = malloc(mibnamelen, M_KTRACE, M_WAITOK);
750 error = kernel_sysctl(curthread, mib, namelen + 2, mibname, &mibnamelen,
751 NULL, 0, &mibnamelen, 0);
752 if (error) {
753 free(mibname, M_KTRACE);
754 return;
755 }
756 req = ktr_getrequest(KTR_SYSCTL);
757 if (req == NULL) {
758 free(mibname, M_KTRACE);
759 return;
760 }
761 req->ktr_header.ktr_len = mibnamelen;
762 req->ktr_buffer = mibname;
763 ktr_submitrequest(curthread, req);
764 }
765
766 void
767 ktrgenio(int fd, enum uio_rw rw, struct uio *uio, int error)
768 {
769 struct ktr_request *req;
770 struct ktr_genio *ktg;
771 int datalen;
772 char *buf;
773
774 if (error) {
775 free(uio, M_IOV);
776 return;
777 }
778 uio->uio_offset = 0;
779 uio->uio_rw = UIO_WRITE;
780 datalen = MIN(uio->uio_resid, ktr_geniosize);
781 buf = malloc(datalen, M_KTRACE, M_WAITOK);
782 error = uiomove(buf, datalen, uio);
783 free(uio, M_IOV);
784 if (error) {
785 free(buf, M_KTRACE);
786 return;
787 }
788 req = ktr_getrequest(KTR_GENIO);
789 if (req == NULL) {
790 free(buf, M_KTRACE);
791 return;
792 }
793 ktg = &req->ktr_data.ktr_genio;
794 ktg->ktr_fd = fd;
795 ktg->ktr_rw = rw;
796 req->ktr_header.ktr_len = datalen;
797 req->ktr_buffer = buf;
798 ktr_submitrequest(curthread, req);
799 }
800
801 void
802 ktrpsig(int sig, sig_t action, sigset_t *mask, int code)
803 {
804 struct thread *td = curthread;
805 struct ktr_request *req;
806 struct ktr_psig *kp;
807
808 req = ktr_getrequest(KTR_PSIG);
809 if (req == NULL)
810 return;
811 kp = &req->ktr_data.ktr_psig;
812 kp->signo = (char)sig;
813 kp->action = action;
814 kp->mask = *mask;
815 kp->code = code;
816 ktr_enqueuerequest(td, req);
817 ktrace_exit(td);
818 }
819
820 void
821 ktrcsw(int out, int user, const char *wmesg)
822 {
823 struct thread *td = curthread;
824 struct ktr_request *req;
825 struct ktr_csw *kc;
826
827 if (__predict_false(curthread->td_pflags & TDP_INKTRACE))
828 return;
829
830 req = ktr_getrequest(KTR_CSW);
831 if (req == NULL)
832 return;
833 kc = &req->ktr_data.ktr_csw;
834 kc->out = out;
835 kc->user = user;
836 if (wmesg != NULL)
837 strlcpy(kc->wmesg, wmesg, sizeof(kc->wmesg));
838 else
839 bzero(kc->wmesg, sizeof(kc->wmesg));
840 ktr_enqueuerequest(td, req);
841 ktrace_exit(td);
842 }
843
844 void
845 ktrstruct(const char *name, const void *data, size_t datalen)
846 {
847 struct ktr_request *req;
848 char *buf;
849 size_t buflen, namelen;
850
851 if (__predict_false(curthread->td_pflags & TDP_INKTRACE))
852 return;
853
854 if (data == NULL)
855 datalen = 0;
856 namelen = strlen(name) + 1;
857 buflen = namelen + datalen;
858 buf = malloc(buflen, M_KTRACE, M_WAITOK);
859 strcpy(buf, name);
860 bcopy(data, buf + namelen, datalen);
861 if ((req = ktr_getrequest(KTR_STRUCT)) == NULL) {
862 free(buf, M_KTRACE);
863 return;
864 }
865 req->ktr_buffer = buf;
866 req->ktr_header.ktr_len = buflen;
867 ktr_submitrequest(curthread, req);
868 }
869
870 void
871 ktrstruct_error(const char *name, const void *data, size_t datalen, int error)
872 {
873
874 if (error == 0)
875 ktrstruct(name, data, datalen);
876 }
877
878 void
879 ktrstructarray(const char *name, enum uio_seg seg, const void *data,
880 int num_items, size_t struct_size)
881 {
882 struct ktr_request *req;
883 struct ktr_struct_array *ksa;
884 char *buf;
885 size_t buflen, datalen, namelen;
886 int max_items;
887
888 if (__predict_false(curthread->td_pflags & TDP_INKTRACE))
889 return;
890 if (num_items < 0)
891 return;
892
893 /* Trim array length to genio size. */
894 max_items = ktr_geniosize / struct_size;
895 if (num_items > max_items) {
896 if (max_items == 0)
897 num_items = 1;
898 else
899 num_items = max_items;
900 }
901 datalen = num_items * struct_size;
902
903 if (data == NULL)
904 datalen = 0;
905
906 namelen = strlen(name) + 1;
907 buflen = namelen + datalen;
908 buf = malloc(buflen, M_KTRACE, M_WAITOK);
909 strcpy(buf, name);
910 if (seg == UIO_SYSSPACE)
911 bcopy(data, buf + namelen, datalen);
912 else {
913 if (copyin(data, buf + namelen, datalen) != 0) {
914 free(buf, M_KTRACE);
915 return;
916 }
917 }
918 if ((req = ktr_getrequest(KTR_STRUCT_ARRAY)) == NULL) {
919 free(buf, M_KTRACE);
920 return;
921 }
922 ksa = &req->ktr_data.ktr_struct_array;
923 ksa->struct_size = struct_size;
924 req->ktr_buffer = buf;
925 req->ktr_header.ktr_len = buflen;
926 ktr_submitrequest(curthread, req);
927 }
928
929 void
930 ktrcapfail(enum ktr_cap_fail_type type, const cap_rights_t *needed,
931 const cap_rights_t *held)
932 {
933 struct thread *td = curthread;
934 struct ktr_request *req;
935 struct ktr_cap_fail *kcf;
936
937 if (__predict_false(curthread->td_pflags & TDP_INKTRACE))
938 return;
939
940 req = ktr_getrequest(KTR_CAPFAIL);
941 if (req == NULL)
942 return;
943 kcf = &req->ktr_data.ktr_cap_fail;
944 kcf->cap_type = type;
945 if (needed != NULL)
946 kcf->cap_needed = *needed;
947 else
948 cap_rights_init(&kcf->cap_needed);
949 if (held != NULL)
950 kcf->cap_held = *held;
951 else
952 cap_rights_init(&kcf->cap_held);
953 ktr_enqueuerequest(td, req);
954 ktrace_exit(td);
955 }
956
957 void
958 ktrfault(vm_offset_t vaddr, int type)
959 {
960 struct thread *td = curthread;
961 struct ktr_request *req;
962 struct ktr_fault *kf;
963
964 if (__predict_false(curthread->td_pflags & TDP_INKTRACE))
965 return;
966
967 req = ktr_getrequest(KTR_FAULT);
968 if (req == NULL)
969 return;
970 kf = &req->ktr_data.ktr_fault;
971 kf->vaddr = vaddr;
972 kf->type = type;
973 ktr_enqueuerequest(td, req);
974 ktrace_exit(td);
975 }
976
977 void
978 ktrfaultend(int result)
979 {
980 struct thread *td = curthread;
981 struct ktr_request *req;
982 struct ktr_faultend *kf;
983
984 if (__predict_false(curthread->td_pflags & TDP_INKTRACE))
985 return;
986
987 req = ktr_getrequest(KTR_FAULTEND);
988 if (req == NULL)
989 return;
990 kf = &req->ktr_data.ktr_faultend;
991 kf->result = result;
992 ktr_enqueuerequest(td, req);
993 ktrace_exit(td);
994 }
995 #endif /* KTRACE */
996
997 /* Interface and common routines */
998
999 #ifndef _SYS_SYSPROTO_H_
1000 struct ktrace_args {
1001 char *fname;
1002 int ops;
1003 int facs;
1004 int pid;
1005 };
1006 #endif
1007 /* ARGSUSED */
1008 int
1009 sys_ktrace(struct thread *td, struct ktrace_args *uap)
1010 {
1011 #ifdef KTRACE
1012 struct vnode *vp = NULL;
1013 struct proc *p;
1014 struct pgrp *pg;
1015 int facs = uap->facs & ~KTRFAC_ROOT;
1016 int ops = KTROP(uap->ops);
1017 int descend = uap->ops & KTRFLAG_DESCEND;
1018 int ret = 0;
1019 int flags, error = 0;
1020 struct nameidata nd;
1021 struct ktr_io_params *kiop, *old_kiop;
1022
1023 /*
1024 * Need something to (un)trace.
1025 */
1026 if (ops != KTROP_CLEARFILE && facs == 0)
1027 return (EINVAL);
1028
1029 kiop = NULL;
1030 if (ops != KTROP_CLEAR) {
1031 /*
1032 * an operation which requires a file argument.
1033 */
1034 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->fname);
1035 flags = FREAD | FWRITE | O_NOFOLLOW;
1036 error = vn_open(&nd, &flags, 0, NULL);
1037 if (error)
1038 return (error);
1039 NDFREE_PNBUF(&nd);
1040 vp = nd.ni_vp;
1041 VOP_UNLOCK(vp);
1042 if (vp->v_type != VREG) {
1043 (void)vn_close(vp, FREAD|FWRITE, td->td_ucred, td);
1044 return (EACCES);
1045 }
1046 kiop = ktr_io_params_alloc(td, vp);
1047 }
1048
1049 /*
1050 * Clear all uses of the tracefile.
1051 */
1052 ktrace_enter(td);
1053 if (ops == KTROP_CLEARFILE) {
1054 restart:
1055 sx_slock(&allproc_lock);
1056 FOREACH_PROC_IN_SYSTEM(p) {
1057 old_kiop = NULL;
1058 PROC_LOCK(p);
1059 if (p->p_ktrioparms != NULL &&
1060 p->p_ktrioparms->vp == vp) {
1061 if (ktrcanset(td, p)) {
1062 mtx_lock(&ktrace_mtx);
1063 old_kiop = ktr_freeproc(p);
1064 mtx_unlock(&ktrace_mtx);
1065 } else
1066 error = EPERM;
1067 }
1068 PROC_UNLOCK(p);
1069 if (old_kiop != NULL) {
1070 sx_sunlock(&allproc_lock);
1071 ktr_io_params_free(old_kiop);
1072 goto restart;
1073 }
1074 }
1075 sx_sunlock(&allproc_lock);
1076 goto done;
1077 }
1078 /*
1079 * do it
1080 */
1081 sx_slock(&proctree_lock);
1082 if (uap->pid < 0) {
1083 /*
1084 * by process group
1085 */
1086 pg = pgfind(-uap->pid);
1087 if (pg == NULL) {
1088 sx_sunlock(&proctree_lock);
1089 error = ESRCH;
1090 goto done;
1091 }
1092
1093 /*
1094 * ktrops() may call vrele(). Lock pg_members
1095 * by the proctree_lock rather than pg_mtx.
1096 */
1097 PGRP_UNLOCK(pg);
1098 if (LIST_EMPTY(&pg->pg_members)) {
1099 sx_sunlock(&proctree_lock);
1100 error = ESRCH;
1101 goto done;
1102 }
1103 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
1104 PROC_LOCK(p);
1105 if (descend)
1106 ret |= ktrsetchildren(td, p, ops, facs, kiop);
1107 else
1108 ret |= ktrops(td, p, ops, facs, kiop);
1109 }
1110 } else {
1111 /*
1112 * by pid
1113 */
1114 p = pfind(uap->pid);
1115 if (p == NULL) {
1116 error = ESRCH;
1117 sx_sunlock(&proctree_lock);
1118 goto done;
1119 }
1120 if (descend)
1121 ret |= ktrsetchildren(td, p, ops, facs, kiop);
1122 else
1123 ret |= ktrops(td, p, ops, facs, kiop);
1124 }
1125 sx_sunlock(&proctree_lock);
1126 if (!ret)
1127 error = EPERM;
1128 done:
1129 if (kiop != NULL) {
1130 mtx_lock(&ktrace_mtx);
1131 kiop = ktr_io_params_rele(kiop);
1132 mtx_unlock(&ktrace_mtx);
1133 ktr_io_params_free(kiop);
1134 }
1135 ktrace_exit(td);
1136 return (error);
1137 #else /* !KTRACE */
1138 return (ENOSYS);
1139 #endif /* KTRACE */
1140 }
1141
1142 /* ARGSUSED */
1143 int
1144 sys_utrace(struct thread *td, struct utrace_args *uap)
1145 {
1146
1147 #ifdef KTRACE
1148 struct ktr_request *req;
1149 void *cp;
1150 int error;
1151
1152 if (!KTRPOINT(td, KTR_USER))
1153 return (0);
1154 if (uap->len > KTR_USER_MAXLEN)
1155 return (EINVAL);
1156 cp = malloc(uap->len, M_KTRACE, M_WAITOK);
1157 error = copyin(uap->addr, cp, uap->len);
1158 if (error) {
1159 free(cp, M_KTRACE);
1160 return (error);
1161 }
1162 req = ktr_getrequest(KTR_USER);
1163 if (req == NULL) {
1164 free(cp, M_KTRACE);
1165 return (ENOMEM);
1166 }
1167 req->ktr_buffer = cp;
1168 req->ktr_header.ktr_len = uap->len;
1169 ktr_submitrequest(td, req);
1170 return (0);
1171 #else /* !KTRACE */
1172 return (ENOSYS);
1173 #endif /* KTRACE */
1174 }
1175
1176 #ifdef KTRACE
1177 static int
1178 ktrops(struct thread *td, struct proc *p, int ops, int facs,
1179 struct ktr_io_params *new_kiop)
1180 {
1181 struct ktr_io_params *old_kiop;
1182
1183 PROC_LOCK_ASSERT(p, MA_OWNED);
1184 if (!ktrcanset(td, p)) {
1185 PROC_UNLOCK(p);
1186 return (0);
1187 }
1188 if ((ops == KTROP_SET && p->p_state == PRS_NEW) ||
1189 p_cansee(td, p) != 0) {
1190 /*
1191 * Disallow setting trace points if the process is being born.
1192 * This avoids races with trace point inheritance in
1193 * ktrprocfork().
1194 */
1195 PROC_UNLOCK(p);
1196 return (0);
1197 }
1198 if ((p->p_flag & P_WEXIT) != 0) {
1199 /*
1200 * There's nothing to do if the process is exiting, but avoid
1201 * signaling an error.
1202 */
1203 PROC_UNLOCK(p);
1204 return (1);
1205 }
1206 old_kiop = NULL;
1207 mtx_lock(&ktrace_mtx);
1208 if (ops == KTROP_SET) {
1209 if (p->p_ktrioparms != NULL &&
1210 p->p_ktrioparms->vp != new_kiop->vp) {
1211 /* if trace file already in use, relinquish below */
1212 old_kiop = ktr_io_params_rele(p->p_ktrioparms);
1213 p->p_ktrioparms = NULL;
1214 }
1215 if (p->p_ktrioparms == NULL) {
1216 p->p_ktrioparms = new_kiop;
1217 ktr_io_params_ref(new_kiop);
1218 }
1219 p->p_traceflag |= facs;
1220 if (priv_check(td, PRIV_KTRACE) == 0)
1221 p->p_traceflag |= KTRFAC_ROOT;
1222 } else {
1223 /* KTROP_CLEAR */
1224 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0)
1225 /* no more tracing */
1226 old_kiop = ktr_freeproc(p);
1227 }
1228 mtx_unlock(&ktrace_mtx);
1229 if ((p->p_traceflag & KTRFAC_MASK) != 0)
1230 ktrprocctor_entered(td, p);
1231 PROC_UNLOCK(p);
1232 ktr_io_params_free(old_kiop);
1233
1234 return (1);
1235 }
1236
1237 static int
1238 ktrsetchildren(struct thread *td, struct proc *top, int ops, int facs,
1239 struct ktr_io_params *new_kiop)
1240 {
1241 struct proc *p;
1242 int ret = 0;
1243
1244 p = top;
1245 PROC_LOCK_ASSERT(p, MA_OWNED);
1246 sx_assert(&proctree_lock, SX_LOCKED);
1247 for (;;) {
1248 ret |= ktrops(td, p, ops, facs, new_kiop);
1249 /*
1250 * If this process has children, descend to them next,
1251 * otherwise do any siblings, and if done with this level,
1252 * follow back up the tree (but not past top).
1253 */
1254 if (!LIST_EMPTY(&p->p_children))
1255 p = LIST_FIRST(&p->p_children);
1256 else for (;;) {
1257 if (p == top)
1258 return (ret);
1259 if (LIST_NEXT(p, p_sibling)) {
1260 p = LIST_NEXT(p, p_sibling);
1261 break;
1262 }
1263 p = p->p_pptr;
1264 }
1265 PROC_LOCK(p);
1266 }
1267 /*NOTREACHED*/
1268 }
1269
1270 static void
1271 ktr_writerequest(struct thread *td, struct ktr_request *req)
1272 {
1273 struct ktr_io_params *kiop, *kiop1;
1274 struct ktr_header *kth;
1275 struct vnode *vp;
1276 struct proc *p;
1277 struct ucred *cred;
1278 struct uio auio;
1279 struct iovec aiov[3];
1280 struct mount *mp;
1281 off_t lim;
1282 int datalen, buflen;
1283 int error;
1284
1285 p = td->td_proc;
1286
1287 /*
1288 * We reference the kiop for use in I/O in case ktrace is
1289 * disabled on the process as we write out the request.
1290 */
1291 mtx_lock(&ktrace_mtx);
1292 kiop = p->p_ktrioparms;
1293
1294 /*
1295 * If kiop is NULL, it has been cleared out from under this
1296 * request, so just drop it.
1297 */
1298 if (kiop == NULL) {
1299 mtx_unlock(&ktrace_mtx);
1300 return;
1301 }
1302
1303 ktr_io_params_ref(kiop);
1304 vp = kiop->vp;
1305 cred = kiop->cr;
1306 lim = kiop->lim;
1307
1308 KASSERT(cred != NULL, ("ktr_writerequest: cred == NULL"));
1309 mtx_unlock(&ktrace_mtx);
1310
1311 kth = &req->ktr_header;
1312 KASSERT(((u_short)kth->ktr_type & ~KTR_TYPE) < nitems(data_lengths),
1313 ("data_lengths array overflow"));
1314 datalen = data_lengths[(u_short)kth->ktr_type & ~KTR_TYPE];
1315 buflen = kth->ktr_len;
1316 auio.uio_iov = &aiov[0];
1317 auio.uio_offset = 0;
1318 auio.uio_segflg = UIO_SYSSPACE;
1319 auio.uio_rw = UIO_WRITE;
1320 aiov[0].iov_base = (caddr_t)kth;
1321 aiov[0].iov_len = sizeof(struct ktr_header);
1322 auio.uio_resid = sizeof(struct ktr_header);
1323 auio.uio_iovcnt = 1;
1324 auio.uio_td = td;
1325 if (datalen != 0) {
1326 aiov[1].iov_base = (caddr_t)&req->ktr_data;
1327 aiov[1].iov_len = datalen;
1328 auio.uio_resid += datalen;
1329 auio.uio_iovcnt++;
1330 kth->ktr_len += datalen;
1331 }
1332 if (buflen != 0) {
1333 KASSERT(req->ktr_buffer != NULL, ("ktrace: nothing to write"));
1334 aiov[auio.uio_iovcnt].iov_base = req->ktr_buffer;
1335 aiov[auio.uio_iovcnt].iov_len = buflen;
1336 auio.uio_resid += buflen;
1337 auio.uio_iovcnt++;
1338 }
1339
1340 vn_start_write(vp, &mp, V_WAIT);
1341 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1342 td->td_ktr_io_lim = lim;
1343 #ifdef MAC
1344 error = mac_vnode_check_write(cred, NOCRED, vp);
1345 if (error == 0)
1346 #endif
1347 error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, cred);
1348 VOP_UNLOCK(vp);
1349 vn_finished_write(mp);
1350 if (error == 0) {
1351 mtx_lock(&ktrace_mtx);
1352 kiop = ktr_io_params_rele(kiop);
1353 mtx_unlock(&ktrace_mtx);
1354 ktr_io_params_free(kiop);
1355 return;
1356 }
1357
1358 /*
1359 * If error encountered, give up tracing on this vnode on this
1360 * process. Other processes might still be suitable for
1361 * writes to this vnode.
1362 */
1363 log(LOG_NOTICE,
1364 "ktrace write failed, errno %d, tracing stopped for pid %d\n",
1365 error, p->p_pid);
1366
1367 kiop1 = NULL;
1368 PROC_LOCK(p);
1369 mtx_lock(&ktrace_mtx);
1370 if (p->p_ktrioparms != NULL && p->p_ktrioparms->vp == vp)
1371 kiop1 = ktr_freeproc(p);
1372 kiop = ktr_io_params_rele(kiop);
1373 mtx_unlock(&ktrace_mtx);
1374 PROC_UNLOCK(p);
1375 ktr_io_params_free(kiop1);
1376 ktr_io_params_free(kiop);
1377 }
1378
1379 /*
1380 * Return true if caller has permission to set the ktracing state
1381 * of target. Essentially, the target can't possess any
1382 * more permissions than the caller. KTRFAC_ROOT signifies that
1383 * root previously set the tracing status on the target process, and
1384 * so, only root may further change it.
1385 */
1386 static int
1387 ktrcanset(struct thread *td, struct proc *targetp)
1388 {
1389
1390 PROC_LOCK_ASSERT(targetp, MA_OWNED);
1391 if (targetp->p_traceflag & KTRFAC_ROOT &&
1392 priv_check(td, PRIV_KTRACE))
1393 return (0);
1394
1395 if (p_candebug(td, targetp) != 0)
1396 return (0);
1397
1398 return (1);
1399 }
1400
1401 #endif /* KTRACE */
Cache object: ddb303a459d209d98da0feae3479a123
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