1 /*-
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California.
4 * Copyright (c) 2005 Robert N. M. Watson
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 4. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 *
31 * @(#)kern_ktrace.c 8.2 (Berkeley) 9/23/93
32 */
33
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD: releng/11.1/sys/kern/kern_ktrace.c 315470 2017-03-18 03:49:50Z kib $");
36
37 #include "opt_ktrace.h"
38
39 #include <sys/param.h>
40 #include <sys/capsicum.h>
41 #include <sys/systm.h>
42 #include <sys/fcntl.h>
43 #include <sys/kernel.h>
44 #include <sys/kthread.h>
45 #include <sys/lock.h>
46 #include <sys/mutex.h>
47 #include <sys/malloc.h>
48 #include <sys/mount.h>
49 #include <sys/namei.h>
50 #include <sys/priv.h>
51 #include <sys/proc.h>
52 #include <sys/unistd.h>
53 #include <sys/vnode.h>
54 #include <sys/socket.h>
55 #include <sys/stat.h>
56 #include <sys/ktrace.h>
57 #include <sys/sx.h>
58 #include <sys/sysctl.h>
59 #include <sys/sysent.h>
60 #include <sys/syslog.h>
61 #include <sys/sysproto.h>
62
63 #include <security/mac/mac_framework.h>
64
65 /*
66 * The ktrace facility allows the tracing of certain key events in user space
67 * processes, such as system calls, signal delivery, context switches, and
68 * user generated events using utrace(2). It works by streaming event
69 * records and data to a vnode associated with the process using the
70 * ktrace(2) system call. In general, records can be written directly from
71 * the context that generates the event. One important exception to this is
72 * during a context switch, where sleeping is not permitted. To handle this
73 * case, trace events are generated using in-kernel ktr_request records, and
74 * then delivered to disk at a convenient moment -- either immediately, the
75 * next traceable event, at system call return, or at process exit.
76 *
77 * When dealing with multiple threads or processes writing to the same event
78 * log, ordering guarantees are weak: specifically, if an event has multiple
79 * records (i.e., system call enter and return), they may be interlaced with
80 * records from another event. Process and thread ID information is provided
81 * in the record, and user applications can de-interlace events if required.
82 */
83
84 static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE");
85
86 #ifdef KTRACE
87
88 FEATURE(ktrace, "Kernel support for system-call tracing");
89
90 #ifndef KTRACE_REQUEST_POOL
91 #define KTRACE_REQUEST_POOL 100
92 #endif
93
94 struct ktr_request {
95 struct ktr_header ktr_header;
96 void *ktr_buffer;
97 union {
98 struct ktr_proc_ctor ktr_proc_ctor;
99 struct ktr_cap_fail ktr_cap_fail;
100 struct ktr_syscall ktr_syscall;
101 struct ktr_sysret ktr_sysret;
102 struct ktr_genio ktr_genio;
103 struct ktr_psig ktr_psig;
104 struct ktr_csw ktr_csw;
105 struct ktr_fault ktr_fault;
106 struct ktr_faultend ktr_faultend;
107 } ktr_data;
108 STAILQ_ENTRY(ktr_request) ktr_list;
109 };
110
111 static int data_lengths[] = {
112 [KTR_SYSCALL] = offsetof(struct ktr_syscall, ktr_args),
113 [KTR_SYSRET] = sizeof(struct ktr_sysret),
114 [KTR_NAMEI] = 0,
115 [KTR_GENIO] = sizeof(struct ktr_genio),
116 [KTR_PSIG] = sizeof(struct ktr_psig),
117 [KTR_CSW] = sizeof(struct ktr_csw),
118 [KTR_USER] = 0,
119 [KTR_STRUCT] = 0,
120 [KTR_SYSCTL] = 0,
121 [KTR_PROCCTOR] = sizeof(struct ktr_proc_ctor),
122 [KTR_PROCDTOR] = 0,
123 [KTR_CAPFAIL] = sizeof(struct ktr_cap_fail),
124 [KTR_FAULT] = sizeof(struct ktr_fault),
125 [KTR_FAULTEND] = sizeof(struct ktr_faultend),
126 };
127
128 static STAILQ_HEAD(, ktr_request) ktr_free;
129
130 static SYSCTL_NODE(_kern, OID_AUTO, ktrace, CTLFLAG_RD, 0, "KTRACE options");
131
132 static u_int ktr_requestpool = KTRACE_REQUEST_POOL;
133 TUNABLE_INT("kern.ktrace.request_pool", &ktr_requestpool);
134
135 u_int ktr_geniosize = PAGE_SIZE;
136 SYSCTL_UINT(_kern_ktrace, OID_AUTO, genio_size, CTLFLAG_RWTUN, &ktr_geniosize,
137 0, "Maximum size of genio event payload");
138
139 static int print_message = 1;
140 static struct mtx ktrace_mtx;
141 static struct sx ktrace_sx;
142
143 static void ktrace_init(void *dummy);
144 static int sysctl_kern_ktrace_request_pool(SYSCTL_HANDLER_ARGS);
145 static u_int ktrace_resize_pool(u_int oldsize, u_int newsize);
146 static struct ktr_request *ktr_getrequest_entered(struct thread *td, int type);
147 static struct ktr_request *ktr_getrequest(int type);
148 static void ktr_submitrequest(struct thread *td, struct ktr_request *req);
149 static void ktr_freeproc(struct proc *p, struct ucred **uc,
150 struct vnode **vp);
151 static void ktr_freerequest(struct ktr_request *req);
152 static void ktr_freerequest_locked(struct ktr_request *req);
153 static void ktr_writerequest(struct thread *td, struct ktr_request *req);
154 static int ktrcanset(struct thread *,struct proc *);
155 static int ktrsetchildren(struct thread *,struct proc *,int,int,struct vnode *);
156 static int ktrops(struct thread *,struct proc *,int,int,struct vnode *);
157 static void ktrprocctor_entered(struct thread *, struct proc *);
158
159 /*
160 * ktrace itself generates events, such as context switches, which we do not
161 * wish to trace. Maintain a flag, TDP_INKTRACE, on each thread to determine
162 * whether or not it is in a region where tracing of events should be
163 * suppressed.
164 */
165 static void
166 ktrace_enter(struct thread *td)
167 {
168
169 KASSERT(!(td->td_pflags & TDP_INKTRACE), ("ktrace_enter: flag set"));
170 td->td_pflags |= TDP_INKTRACE;
171 }
172
173 static void
174 ktrace_exit(struct thread *td)
175 {
176
177 KASSERT(td->td_pflags & TDP_INKTRACE, ("ktrace_exit: flag not set"));
178 td->td_pflags &= ~TDP_INKTRACE;
179 }
180
181 static void
182 ktrace_assert(struct thread *td)
183 {
184
185 KASSERT(td->td_pflags & TDP_INKTRACE, ("ktrace_assert: flag not set"));
186 }
187
188 static void
189 ktrace_init(void *dummy)
190 {
191 struct ktr_request *req;
192 int i;
193
194 mtx_init(&ktrace_mtx, "ktrace", NULL, MTX_DEF | MTX_QUIET);
195 sx_init(&ktrace_sx, "ktrace_sx");
196 STAILQ_INIT(&ktr_free);
197 for (i = 0; i < ktr_requestpool; i++) {
198 req = malloc(sizeof(struct ktr_request), M_KTRACE, M_WAITOK);
199 STAILQ_INSERT_HEAD(&ktr_free, req, ktr_list);
200 }
201 }
202 SYSINIT(ktrace_init, SI_SUB_KTRACE, SI_ORDER_ANY, ktrace_init, NULL);
203
204 static int
205 sysctl_kern_ktrace_request_pool(SYSCTL_HANDLER_ARGS)
206 {
207 struct thread *td;
208 u_int newsize, oldsize, wantsize;
209 int error;
210
211 /* Handle easy read-only case first to avoid warnings from GCC. */
212 if (!req->newptr) {
213 oldsize = ktr_requestpool;
214 return (SYSCTL_OUT(req, &oldsize, sizeof(u_int)));
215 }
216
217 error = SYSCTL_IN(req, &wantsize, sizeof(u_int));
218 if (error)
219 return (error);
220 td = curthread;
221 ktrace_enter(td);
222 oldsize = ktr_requestpool;
223 newsize = ktrace_resize_pool(oldsize, wantsize);
224 ktrace_exit(td);
225 error = SYSCTL_OUT(req, &oldsize, sizeof(u_int));
226 if (error)
227 return (error);
228 if (wantsize > oldsize && newsize < wantsize)
229 return (ENOSPC);
230 return (0);
231 }
232 SYSCTL_PROC(_kern_ktrace, OID_AUTO, request_pool, CTLTYPE_UINT|CTLFLAG_RW,
233 &ktr_requestpool, 0, sysctl_kern_ktrace_request_pool, "IU",
234 "Pool buffer size for ktrace(1)");
235
236 static u_int
237 ktrace_resize_pool(u_int oldsize, u_int newsize)
238 {
239 STAILQ_HEAD(, ktr_request) ktr_new;
240 struct ktr_request *req;
241 int bound;
242
243 print_message = 1;
244 bound = newsize - oldsize;
245 if (bound == 0)
246 return (ktr_requestpool);
247 if (bound < 0) {
248 mtx_lock(&ktrace_mtx);
249 /* Shrink pool down to newsize if possible. */
250 while (bound++ < 0) {
251 req = STAILQ_FIRST(&ktr_free);
252 if (req == NULL)
253 break;
254 STAILQ_REMOVE_HEAD(&ktr_free, ktr_list);
255 ktr_requestpool--;
256 free(req, M_KTRACE);
257 }
258 } else {
259 /* Grow pool up to newsize. */
260 STAILQ_INIT(&ktr_new);
261 while (bound-- > 0) {
262 req = malloc(sizeof(struct ktr_request), M_KTRACE,
263 M_WAITOK);
264 STAILQ_INSERT_HEAD(&ktr_new, req, ktr_list);
265 }
266 mtx_lock(&ktrace_mtx);
267 STAILQ_CONCAT(&ktr_free, &ktr_new);
268 ktr_requestpool += (newsize - oldsize);
269 }
270 mtx_unlock(&ktrace_mtx);
271 return (ktr_requestpool);
272 }
273
274 /* ktr_getrequest() assumes that ktr_comm[] is the same size as td_name[]. */
275 CTASSERT(sizeof(((struct ktr_header *)NULL)->ktr_comm) ==
276 (sizeof((struct thread *)NULL)->td_name));
277
278 static struct ktr_request *
279 ktr_getrequest_entered(struct thread *td, int type)
280 {
281 struct ktr_request *req;
282 struct proc *p = td->td_proc;
283 int pm;
284
285 mtx_lock(&ktrace_mtx);
286 if (!KTRCHECK(td, type)) {
287 mtx_unlock(&ktrace_mtx);
288 return (NULL);
289 }
290 req = STAILQ_FIRST(&ktr_free);
291 if (req != NULL) {
292 STAILQ_REMOVE_HEAD(&ktr_free, ktr_list);
293 req->ktr_header.ktr_type = type;
294 if (p->p_traceflag & KTRFAC_DROP) {
295 req->ktr_header.ktr_type |= KTR_DROP;
296 p->p_traceflag &= ~KTRFAC_DROP;
297 }
298 mtx_unlock(&ktrace_mtx);
299 microtime(&req->ktr_header.ktr_time);
300 req->ktr_header.ktr_pid = p->p_pid;
301 req->ktr_header.ktr_tid = td->td_tid;
302 bcopy(td->td_name, req->ktr_header.ktr_comm,
303 sizeof(req->ktr_header.ktr_comm));
304 req->ktr_buffer = NULL;
305 req->ktr_header.ktr_len = 0;
306 } else {
307 p->p_traceflag |= KTRFAC_DROP;
308 pm = print_message;
309 print_message = 0;
310 mtx_unlock(&ktrace_mtx);
311 if (pm)
312 printf("Out of ktrace request objects.\n");
313 }
314 return (req);
315 }
316
317 static struct ktr_request *
318 ktr_getrequest(int type)
319 {
320 struct thread *td = curthread;
321 struct ktr_request *req;
322
323 ktrace_enter(td);
324 req = ktr_getrequest_entered(td, type);
325 if (req == NULL)
326 ktrace_exit(td);
327
328 return (req);
329 }
330
331 /*
332 * Some trace generation environments don't permit direct access to VFS,
333 * such as during a context switch where sleeping is not allowed. Under these
334 * circumstances, queue a request to the thread to be written asynchronously
335 * later.
336 */
337 static void
338 ktr_enqueuerequest(struct thread *td, struct ktr_request *req)
339 {
340
341 mtx_lock(&ktrace_mtx);
342 STAILQ_INSERT_TAIL(&td->td_proc->p_ktr, req, ktr_list);
343 mtx_unlock(&ktrace_mtx);
344 }
345
346 /*
347 * Drain any pending ktrace records from the per-thread queue to disk. This
348 * is used both internally before committing other records, and also on
349 * system call return. We drain all the ones we can find at the time when
350 * drain is requested, but don't keep draining after that as those events
351 * may be approximately "after" the current event.
352 */
353 static void
354 ktr_drain(struct thread *td)
355 {
356 struct ktr_request *queued_req;
357 STAILQ_HEAD(, ktr_request) local_queue;
358
359 ktrace_assert(td);
360 sx_assert(&ktrace_sx, SX_XLOCKED);
361
362 STAILQ_INIT(&local_queue);
363
364 if (!STAILQ_EMPTY(&td->td_proc->p_ktr)) {
365 mtx_lock(&ktrace_mtx);
366 STAILQ_CONCAT(&local_queue, &td->td_proc->p_ktr);
367 mtx_unlock(&ktrace_mtx);
368
369 while ((queued_req = STAILQ_FIRST(&local_queue))) {
370 STAILQ_REMOVE_HEAD(&local_queue, ktr_list);
371 ktr_writerequest(td, queued_req);
372 ktr_freerequest(queued_req);
373 }
374 }
375 }
376
377 /*
378 * Submit a trace record for immediate commit to disk -- to be used only
379 * where entering VFS is OK. First drain any pending records that may have
380 * been cached in the thread.
381 */
382 static void
383 ktr_submitrequest(struct thread *td, struct ktr_request *req)
384 {
385
386 ktrace_assert(td);
387
388 sx_xlock(&ktrace_sx);
389 ktr_drain(td);
390 ktr_writerequest(td, req);
391 ktr_freerequest(req);
392 sx_xunlock(&ktrace_sx);
393 ktrace_exit(td);
394 }
395
396 static void
397 ktr_freerequest(struct ktr_request *req)
398 {
399
400 mtx_lock(&ktrace_mtx);
401 ktr_freerequest_locked(req);
402 mtx_unlock(&ktrace_mtx);
403 }
404
405 static void
406 ktr_freerequest_locked(struct ktr_request *req)
407 {
408
409 mtx_assert(&ktrace_mtx, MA_OWNED);
410 if (req->ktr_buffer != NULL)
411 free(req->ktr_buffer, M_KTRACE);
412 STAILQ_INSERT_HEAD(&ktr_free, req, ktr_list);
413 }
414
415 /*
416 * Disable tracing for a process and release all associated resources.
417 * The caller is responsible for releasing a reference on the returned
418 * vnode and credentials.
419 */
420 static void
421 ktr_freeproc(struct proc *p, struct ucred **uc, struct vnode **vp)
422 {
423 struct ktr_request *req;
424
425 PROC_LOCK_ASSERT(p, MA_OWNED);
426 mtx_assert(&ktrace_mtx, MA_OWNED);
427 *uc = p->p_tracecred;
428 p->p_tracecred = NULL;
429 if (vp != NULL)
430 *vp = p->p_tracevp;
431 p->p_tracevp = NULL;
432 p->p_traceflag = 0;
433 while ((req = STAILQ_FIRST(&p->p_ktr)) != NULL) {
434 STAILQ_REMOVE_HEAD(&p->p_ktr, ktr_list);
435 ktr_freerequest_locked(req);
436 }
437 }
438
439 void
440 ktrsyscall(code, narg, args)
441 int code, narg;
442 register_t args[];
443 {
444 struct ktr_request *req;
445 struct ktr_syscall *ktp;
446 size_t buflen;
447 char *buf = NULL;
448
449 buflen = sizeof(register_t) * narg;
450 if (buflen > 0) {
451 buf = malloc(buflen, M_KTRACE, M_WAITOK);
452 bcopy(args, buf, buflen);
453 }
454 req = ktr_getrequest(KTR_SYSCALL);
455 if (req == NULL) {
456 if (buf != NULL)
457 free(buf, M_KTRACE);
458 return;
459 }
460 ktp = &req->ktr_data.ktr_syscall;
461 ktp->ktr_code = code;
462 ktp->ktr_narg = narg;
463 if (buflen > 0) {
464 req->ktr_header.ktr_len = buflen;
465 req->ktr_buffer = buf;
466 }
467 ktr_submitrequest(curthread, req);
468 }
469
470 void
471 ktrsysret(code, error, retval)
472 int code, error;
473 register_t retval;
474 {
475 struct ktr_request *req;
476 struct ktr_sysret *ktp;
477
478 req = ktr_getrequest(KTR_SYSRET);
479 if (req == NULL)
480 return;
481 ktp = &req->ktr_data.ktr_sysret;
482 ktp->ktr_code = code;
483 ktp->ktr_error = error;
484 ktp->ktr_retval = ((error == 0) ? retval: 0); /* what about val2 ? */
485 ktr_submitrequest(curthread, req);
486 }
487
488 /*
489 * When a setuid process execs, disable tracing.
490 *
491 * XXX: We toss any pending asynchronous records.
492 */
493 void
494 ktrprocexec(struct proc *p, struct ucred **uc, struct vnode **vp)
495 {
496
497 PROC_LOCK_ASSERT(p, MA_OWNED);
498 mtx_lock(&ktrace_mtx);
499 ktr_freeproc(p, uc, vp);
500 mtx_unlock(&ktrace_mtx);
501 }
502
503 /*
504 * When a process exits, drain per-process asynchronous trace records
505 * and disable tracing.
506 */
507 void
508 ktrprocexit(struct thread *td)
509 {
510 struct ktr_request *req;
511 struct proc *p;
512 struct ucred *cred;
513 struct vnode *vp;
514
515 p = td->td_proc;
516 if (p->p_traceflag == 0)
517 return;
518
519 ktrace_enter(td);
520 req = ktr_getrequest_entered(td, KTR_PROCDTOR);
521 if (req != NULL)
522 ktr_enqueuerequest(td, req);
523 sx_xlock(&ktrace_sx);
524 ktr_drain(td);
525 sx_xunlock(&ktrace_sx);
526 PROC_LOCK(p);
527 mtx_lock(&ktrace_mtx);
528 ktr_freeproc(p, &cred, &vp);
529 mtx_unlock(&ktrace_mtx);
530 PROC_UNLOCK(p);
531 if (vp != NULL)
532 vrele(vp);
533 if (cred != NULL)
534 crfree(cred);
535 ktrace_exit(td);
536 }
537
538 static void
539 ktrprocctor_entered(struct thread *td, struct proc *p)
540 {
541 struct ktr_proc_ctor *ktp;
542 struct ktr_request *req;
543 struct thread *td2;
544
545 ktrace_assert(td);
546 td2 = FIRST_THREAD_IN_PROC(p);
547 req = ktr_getrequest_entered(td2, KTR_PROCCTOR);
548 if (req == NULL)
549 return;
550 ktp = &req->ktr_data.ktr_proc_ctor;
551 ktp->sv_flags = p->p_sysent->sv_flags;
552 ktr_enqueuerequest(td2, req);
553 }
554
555 void
556 ktrprocctor(struct proc *p)
557 {
558 struct thread *td = curthread;
559
560 if ((p->p_traceflag & KTRFAC_MASK) == 0)
561 return;
562
563 ktrace_enter(td);
564 ktrprocctor_entered(td, p);
565 ktrace_exit(td);
566 }
567
568 /*
569 * When a process forks, enable tracing in the new process if needed.
570 */
571 void
572 ktrprocfork(struct proc *p1, struct proc *p2)
573 {
574
575 MPASS(p2->p_tracevp == NULL);
576 MPASS(p2->p_traceflag == 0);
577
578 if (p1->p_traceflag == 0)
579 return;
580
581 PROC_LOCK(p1);
582 mtx_lock(&ktrace_mtx);
583 if (p1->p_traceflag & KTRFAC_INHERIT) {
584 p2->p_traceflag = p1->p_traceflag;
585 if ((p2->p_tracevp = p1->p_tracevp) != NULL) {
586 VREF(p2->p_tracevp);
587 KASSERT(p1->p_tracecred != NULL,
588 ("ktrace vnode with no cred"));
589 p2->p_tracecred = crhold(p1->p_tracecred);
590 }
591 }
592 mtx_unlock(&ktrace_mtx);
593 PROC_UNLOCK(p1);
594
595 ktrprocctor(p2);
596 }
597
598 /*
599 * When a thread returns, drain any asynchronous records generated by the
600 * system call.
601 */
602 void
603 ktruserret(struct thread *td)
604 {
605
606 ktrace_enter(td);
607 sx_xlock(&ktrace_sx);
608 ktr_drain(td);
609 sx_xunlock(&ktrace_sx);
610 ktrace_exit(td);
611 }
612
613 void
614 ktrnamei(path)
615 char *path;
616 {
617 struct ktr_request *req;
618 int namelen;
619 char *buf = NULL;
620
621 namelen = strlen(path);
622 if (namelen > 0) {
623 buf = malloc(namelen, M_KTRACE, M_WAITOK);
624 bcopy(path, buf, namelen);
625 }
626 req = ktr_getrequest(KTR_NAMEI);
627 if (req == NULL) {
628 if (buf != NULL)
629 free(buf, M_KTRACE);
630 return;
631 }
632 if (namelen > 0) {
633 req->ktr_header.ktr_len = namelen;
634 req->ktr_buffer = buf;
635 }
636 ktr_submitrequest(curthread, req);
637 }
638
639 void
640 ktrsysctl(name, namelen)
641 int *name;
642 u_int namelen;
643 {
644 struct ktr_request *req;
645 u_int mib[CTL_MAXNAME + 2];
646 char *mibname;
647 size_t mibnamelen;
648 int error;
649
650 /* Lookup name of mib. */
651 KASSERT(namelen <= CTL_MAXNAME, ("sysctl MIB too long"));
652 mib[0] = 0;
653 mib[1] = 1;
654 bcopy(name, mib + 2, namelen * sizeof(*name));
655 mibnamelen = 128;
656 mibname = malloc(mibnamelen, M_KTRACE, M_WAITOK);
657 error = kernel_sysctl(curthread, mib, namelen + 2, mibname, &mibnamelen,
658 NULL, 0, &mibnamelen, 0);
659 if (error) {
660 free(mibname, M_KTRACE);
661 return;
662 }
663 req = ktr_getrequest(KTR_SYSCTL);
664 if (req == NULL) {
665 free(mibname, M_KTRACE);
666 return;
667 }
668 req->ktr_header.ktr_len = mibnamelen;
669 req->ktr_buffer = mibname;
670 ktr_submitrequest(curthread, req);
671 }
672
673 void
674 ktrgenio(fd, rw, uio, error)
675 int fd;
676 enum uio_rw rw;
677 struct uio *uio;
678 int error;
679 {
680 struct ktr_request *req;
681 struct ktr_genio *ktg;
682 int datalen;
683 char *buf;
684
685 if (error) {
686 free(uio, M_IOV);
687 return;
688 }
689 uio->uio_offset = 0;
690 uio->uio_rw = UIO_WRITE;
691 datalen = MIN(uio->uio_resid, ktr_geniosize);
692 buf = malloc(datalen, M_KTRACE, M_WAITOK);
693 error = uiomove(buf, datalen, uio);
694 free(uio, M_IOV);
695 if (error) {
696 free(buf, M_KTRACE);
697 return;
698 }
699 req = ktr_getrequest(KTR_GENIO);
700 if (req == NULL) {
701 free(buf, M_KTRACE);
702 return;
703 }
704 ktg = &req->ktr_data.ktr_genio;
705 ktg->ktr_fd = fd;
706 ktg->ktr_rw = rw;
707 req->ktr_header.ktr_len = datalen;
708 req->ktr_buffer = buf;
709 ktr_submitrequest(curthread, req);
710 }
711
712 void
713 ktrpsig(sig, action, mask, code)
714 int sig;
715 sig_t action;
716 sigset_t *mask;
717 int code;
718 {
719 struct thread *td = curthread;
720 struct ktr_request *req;
721 struct ktr_psig *kp;
722
723 req = ktr_getrequest(KTR_PSIG);
724 if (req == NULL)
725 return;
726 kp = &req->ktr_data.ktr_psig;
727 kp->signo = (char)sig;
728 kp->action = action;
729 kp->mask = *mask;
730 kp->code = code;
731 ktr_enqueuerequest(td, req);
732 ktrace_exit(td);
733 }
734
735 void
736 ktrcsw(out, user, wmesg)
737 int out, user;
738 const char *wmesg;
739 {
740 struct thread *td = curthread;
741 struct ktr_request *req;
742 struct ktr_csw *kc;
743
744 req = ktr_getrequest(KTR_CSW);
745 if (req == NULL)
746 return;
747 kc = &req->ktr_data.ktr_csw;
748 kc->out = out;
749 kc->user = user;
750 if (wmesg != NULL)
751 strlcpy(kc->wmesg, wmesg, sizeof(kc->wmesg));
752 else
753 bzero(kc->wmesg, sizeof(kc->wmesg));
754 ktr_enqueuerequest(td, req);
755 ktrace_exit(td);
756 }
757
758 void
759 ktrstruct(name, data, datalen)
760 const char *name;
761 void *data;
762 size_t datalen;
763 {
764 struct ktr_request *req;
765 char *buf;
766 size_t buflen, namelen;
767
768 if (data == NULL)
769 datalen = 0;
770 namelen = strlen(name) + 1;
771 buflen = namelen + datalen;
772 buf = malloc(buflen, M_KTRACE, M_WAITOK);
773 strcpy(buf, name);
774 bcopy(data, buf + namelen, datalen);
775 if ((req = ktr_getrequest(KTR_STRUCT)) == NULL) {
776 free(buf, M_KTRACE);
777 return;
778 }
779 req->ktr_buffer = buf;
780 req->ktr_header.ktr_len = buflen;
781 ktr_submitrequest(curthread, req);
782 }
783
784 void
785 ktrcapfail(type, needed, held)
786 enum ktr_cap_fail_type type;
787 const cap_rights_t *needed;
788 const cap_rights_t *held;
789 {
790 struct thread *td = curthread;
791 struct ktr_request *req;
792 struct ktr_cap_fail *kcf;
793
794 req = ktr_getrequest(KTR_CAPFAIL);
795 if (req == NULL)
796 return;
797 kcf = &req->ktr_data.ktr_cap_fail;
798 kcf->cap_type = type;
799 if (needed != NULL)
800 kcf->cap_needed = *needed;
801 else
802 cap_rights_init(&kcf->cap_needed);
803 if (held != NULL)
804 kcf->cap_held = *held;
805 else
806 cap_rights_init(&kcf->cap_held);
807 ktr_enqueuerequest(td, req);
808 ktrace_exit(td);
809 }
810
811 void
812 ktrfault(vaddr, type)
813 vm_offset_t vaddr;
814 int type;
815 {
816 struct thread *td = curthread;
817 struct ktr_request *req;
818 struct ktr_fault *kf;
819
820 req = ktr_getrequest(KTR_FAULT);
821 if (req == NULL)
822 return;
823 kf = &req->ktr_data.ktr_fault;
824 kf->vaddr = vaddr;
825 kf->type = type;
826 ktr_enqueuerequest(td, req);
827 ktrace_exit(td);
828 }
829
830 void
831 ktrfaultend(result)
832 int result;
833 {
834 struct thread *td = curthread;
835 struct ktr_request *req;
836 struct ktr_faultend *kf;
837
838 req = ktr_getrequest(KTR_FAULTEND);
839 if (req == NULL)
840 return;
841 kf = &req->ktr_data.ktr_faultend;
842 kf->result = result;
843 ktr_enqueuerequest(td, req);
844 ktrace_exit(td);
845 }
846 #endif /* KTRACE */
847
848 /* Interface and common routines */
849
850 #ifndef _SYS_SYSPROTO_H_
851 struct ktrace_args {
852 char *fname;
853 int ops;
854 int facs;
855 int pid;
856 };
857 #endif
858 /* ARGSUSED */
859 int
860 sys_ktrace(td, uap)
861 struct thread *td;
862 register struct ktrace_args *uap;
863 {
864 #ifdef KTRACE
865 register struct vnode *vp = NULL;
866 register struct proc *p;
867 struct pgrp *pg;
868 int facs = uap->facs & ~KTRFAC_ROOT;
869 int ops = KTROP(uap->ops);
870 int descend = uap->ops & KTRFLAG_DESCEND;
871 int nfound, ret = 0;
872 int flags, error = 0;
873 struct nameidata nd;
874 struct ucred *cred;
875
876 /*
877 * Need something to (un)trace.
878 */
879 if (ops != KTROP_CLEARFILE && facs == 0)
880 return (EINVAL);
881
882 ktrace_enter(td);
883 if (ops != KTROP_CLEAR) {
884 /*
885 * an operation which requires a file argument.
886 */
887 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->fname, td);
888 flags = FREAD | FWRITE | O_NOFOLLOW;
889 error = vn_open(&nd, &flags, 0, NULL);
890 if (error) {
891 ktrace_exit(td);
892 return (error);
893 }
894 NDFREE(&nd, NDF_ONLY_PNBUF);
895 vp = nd.ni_vp;
896 VOP_UNLOCK(vp, 0);
897 if (vp->v_type != VREG) {
898 (void) vn_close(vp, FREAD|FWRITE, td->td_ucred, td);
899 ktrace_exit(td);
900 return (EACCES);
901 }
902 }
903 /*
904 * Clear all uses of the tracefile.
905 */
906 if (ops == KTROP_CLEARFILE) {
907 int vrele_count;
908
909 vrele_count = 0;
910 sx_slock(&allproc_lock);
911 FOREACH_PROC_IN_SYSTEM(p) {
912 PROC_LOCK(p);
913 if (p->p_tracevp == vp) {
914 if (ktrcanset(td, p)) {
915 mtx_lock(&ktrace_mtx);
916 ktr_freeproc(p, &cred, NULL);
917 mtx_unlock(&ktrace_mtx);
918 vrele_count++;
919 crfree(cred);
920 } else
921 error = EPERM;
922 }
923 PROC_UNLOCK(p);
924 }
925 sx_sunlock(&allproc_lock);
926 if (vrele_count > 0) {
927 while (vrele_count-- > 0)
928 vrele(vp);
929 }
930 goto done;
931 }
932 /*
933 * do it
934 */
935 sx_slock(&proctree_lock);
936 if (uap->pid < 0) {
937 /*
938 * by process group
939 */
940 pg = pgfind(-uap->pid);
941 if (pg == NULL) {
942 sx_sunlock(&proctree_lock);
943 error = ESRCH;
944 goto done;
945 }
946 /*
947 * ktrops() may call vrele(). Lock pg_members
948 * by the proctree_lock rather than pg_mtx.
949 */
950 PGRP_UNLOCK(pg);
951 nfound = 0;
952 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
953 PROC_LOCK(p);
954 if (p->p_state == PRS_NEW ||
955 p_cansee(td, p) != 0) {
956 PROC_UNLOCK(p);
957 continue;
958 }
959 nfound++;
960 if (descend)
961 ret |= ktrsetchildren(td, p, ops, facs, vp);
962 else
963 ret |= ktrops(td, p, ops, facs, vp);
964 }
965 if (nfound == 0) {
966 sx_sunlock(&proctree_lock);
967 error = ESRCH;
968 goto done;
969 }
970 } else {
971 /*
972 * by pid
973 */
974 p = pfind(uap->pid);
975 if (p == NULL)
976 error = ESRCH;
977 else
978 error = p_cansee(td, p);
979 if (error) {
980 if (p != NULL)
981 PROC_UNLOCK(p);
982 sx_sunlock(&proctree_lock);
983 goto done;
984 }
985 if (descend)
986 ret |= ktrsetchildren(td, p, ops, facs, vp);
987 else
988 ret |= ktrops(td, p, ops, facs, vp);
989 }
990 sx_sunlock(&proctree_lock);
991 if (!ret)
992 error = EPERM;
993 done:
994 if (vp != NULL)
995 (void) vn_close(vp, FWRITE, td->td_ucred, td);
996 ktrace_exit(td);
997 return (error);
998 #else /* !KTRACE */
999 return (ENOSYS);
1000 #endif /* KTRACE */
1001 }
1002
1003 /* ARGSUSED */
1004 int
1005 sys_utrace(td, uap)
1006 struct thread *td;
1007 register struct utrace_args *uap;
1008 {
1009
1010 #ifdef KTRACE
1011 struct ktr_request *req;
1012 void *cp;
1013 int error;
1014
1015 if (!KTRPOINT(td, KTR_USER))
1016 return (0);
1017 if (uap->len > KTR_USER_MAXLEN)
1018 return (EINVAL);
1019 cp = malloc(uap->len, M_KTRACE, M_WAITOK);
1020 error = copyin(uap->addr, cp, uap->len);
1021 if (error) {
1022 free(cp, M_KTRACE);
1023 return (error);
1024 }
1025 req = ktr_getrequest(KTR_USER);
1026 if (req == NULL) {
1027 free(cp, M_KTRACE);
1028 return (ENOMEM);
1029 }
1030 req->ktr_buffer = cp;
1031 req->ktr_header.ktr_len = uap->len;
1032 ktr_submitrequest(td, req);
1033 return (0);
1034 #else /* !KTRACE */
1035 return (ENOSYS);
1036 #endif /* KTRACE */
1037 }
1038
1039 #ifdef KTRACE
1040 static int
1041 ktrops(td, p, ops, facs, vp)
1042 struct thread *td;
1043 struct proc *p;
1044 int ops, facs;
1045 struct vnode *vp;
1046 {
1047 struct vnode *tracevp = NULL;
1048 struct ucred *tracecred = NULL;
1049
1050 PROC_LOCK_ASSERT(p, MA_OWNED);
1051 if (!ktrcanset(td, p)) {
1052 PROC_UNLOCK(p);
1053 return (0);
1054 }
1055 if (p->p_flag & P_WEXIT) {
1056 /* If the process is exiting, just ignore it. */
1057 PROC_UNLOCK(p);
1058 return (1);
1059 }
1060 mtx_lock(&ktrace_mtx);
1061 if (ops == KTROP_SET) {
1062 if (p->p_tracevp != vp) {
1063 /*
1064 * if trace file already in use, relinquish below
1065 */
1066 tracevp = p->p_tracevp;
1067 VREF(vp);
1068 p->p_tracevp = vp;
1069 }
1070 if (p->p_tracecred != td->td_ucred) {
1071 tracecred = p->p_tracecred;
1072 p->p_tracecred = crhold(td->td_ucred);
1073 }
1074 p->p_traceflag |= facs;
1075 if (priv_check(td, PRIV_KTRACE) == 0)
1076 p->p_traceflag |= KTRFAC_ROOT;
1077 } else {
1078 /* KTROP_CLEAR */
1079 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0)
1080 /* no more tracing */
1081 ktr_freeproc(p, &tracecred, &tracevp);
1082 }
1083 mtx_unlock(&ktrace_mtx);
1084 if ((p->p_traceflag & KTRFAC_MASK) != 0)
1085 ktrprocctor_entered(td, p);
1086 PROC_UNLOCK(p);
1087 if (tracevp != NULL)
1088 vrele(tracevp);
1089 if (tracecred != NULL)
1090 crfree(tracecred);
1091
1092 return (1);
1093 }
1094
1095 static int
1096 ktrsetchildren(td, top, ops, facs, vp)
1097 struct thread *td;
1098 struct proc *top;
1099 int ops, facs;
1100 struct vnode *vp;
1101 {
1102 register struct proc *p;
1103 register int ret = 0;
1104
1105 p = top;
1106 PROC_LOCK_ASSERT(p, MA_OWNED);
1107 sx_assert(&proctree_lock, SX_LOCKED);
1108 for (;;) {
1109 ret |= ktrops(td, p, ops, facs, vp);
1110 /*
1111 * If this process has children, descend to them next,
1112 * otherwise do any siblings, and if done with this level,
1113 * follow back up the tree (but not past top).
1114 */
1115 if (!LIST_EMPTY(&p->p_children))
1116 p = LIST_FIRST(&p->p_children);
1117 else for (;;) {
1118 if (p == top)
1119 return (ret);
1120 if (LIST_NEXT(p, p_sibling)) {
1121 p = LIST_NEXT(p, p_sibling);
1122 break;
1123 }
1124 p = p->p_pptr;
1125 }
1126 PROC_LOCK(p);
1127 }
1128 /*NOTREACHED*/
1129 }
1130
1131 static void
1132 ktr_writerequest(struct thread *td, struct ktr_request *req)
1133 {
1134 struct ktr_header *kth;
1135 struct vnode *vp;
1136 struct proc *p;
1137 struct ucred *cred;
1138 struct uio auio;
1139 struct iovec aiov[3];
1140 struct mount *mp;
1141 int datalen, buflen, vrele_count;
1142 int error;
1143
1144 /*
1145 * We hold the vnode and credential for use in I/O in case ktrace is
1146 * disabled on the process as we write out the request.
1147 *
1148 * XXXRW: This is not ideal: we could end up performing a write after
1149 * the vnode has been closed.
1150 */
1151 mtx_lock(&ktrace_mtx);
1152 vp = td->td_proc->p_tracevp;
1153 cred = td->td_proc->p_tracecred;
1154
1155 /*
1156 * If vp is NULL, the vp has been cleared out from under this
1157 * request, so just drop it. Make sure the credential and vnode are
1158 * in sync: we should have both or neither.
1159 */
1160 if (vp == NULL) {
1161 KASSERT(cred == NULL, ("ktr_writerequest: cred != NULL"));
1162 mtx_unlock(&ktrace_mtx);
1163 return;
1164 }
1165 VREF(vp);
1166 KASSERT(cred != NULL, ("ktr_writerequest: cred == NULL"));
1167 crhold(cred);
1168 mtx_unlock(&ktrace_mtx);
1169
1170 kth = &req->ktr_header;
1171 KASSERT(((u_short)kth->ktr_type & ~KTR_DROP) < nitems(data_lengths),
1172 ("data_lengths array overflow"));
1173 datalen = data_lengths[(u_short)kth->ktr_type & ~KTR_DROP];
1174 buflen = kth->ktr_len;
1175 auio.uio_iov = &aiov[0];
1176 auio.uio_offset = 0;
1177 auio.uio_segflg = UIO_SYSSPACE;
1178 auio.uio_rw = UIO_WRITE;
1179 aiov[0].iov_base = (caddr_t)kth;
1180 aiov[0].iov_len = sizeof(struct ktr_header);
1181 auio.uio_resid = sizeof(struct ktr_header);
1182 auio.uio_iovcnt = 1;
1183 auio.uio_td = td;
1184 if (datalen != 0) {
1185 aiov[1].iov_base = (caddr_t)&req->ktr_data;
1186 aiov[1].iov_len = datalen;
1187 auio.uio_resid += datalen;
1188 auio.uio_iovcnt++;
1189 kth->ktr_len += datalen;
1190 }
1191 if (buflen != 0) {
1192 KASSERT(req->ktr_buffer != NULL, ("ktrace: nothing to write"));
1193 aiov[auio.uio_iovcnt].iov_base = req->ktr_buffer;
1194 aiov[auio.uio_iovcnt].iov_len = buflen;
1195 auio.uio_resid += buflen;
1196 auio.uio_iovcnt++;
1197 }
1198
1199 vn_start_write(vp, &mp, V_WAIT);
1200 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1201 #ifdef MAC
1202 error = mac_vnode_check_write(cred, NOCRED, vp);
1203 if (error == 0)
1204 #endif
1205 error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, cred);
1206 VOP_UNLOCK(vp, 0);
1207 vn_finished_write(mp);
1208 crfree(cred);
1209 if (!error) {
1210 vrele(vp);
1211 return;
1212 }
1213
1214 /*
1215 * If error encountered, give up tracing on this vnode. We defer
1216 * all the vrele()'s on the vnode until after we are finished walking
1217 * the various lists to avoid needlessly holding locks.
1218 * NB: at this point we still hold the vnode reference that must
1219 * not go away as we need the valid vnode to compare with. Thus let
1220 * vrele_count start at 1 and the reference will be freed
1221 * by the loop at the end after our last use of vp.
1222 */
1223 log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n",
1224 error);
1225 vrele_count = 1;
1226 /*
1227 * First, clear this vnode from being used by any processes in the
1228 * system.
1229 * XXX - If one process gets an EPERM writing to the vnode, should
1230 * we really do this? Other processes might have suitable
1231 * credentials for the operation.
1232 */
1233 cred = NULL;
1234 sx_slock(&allproc_lock);
1235 FOREACH_PROC_IN_SYSTEM(p) {
1236 PROC_LOCK(p);
1237 if (p->p_tracevp == vp) {
1238 mtx_lock(&ktrace_mtx);
1239 ktr_freeproc(p, &cred, NULL);
1240 mtx_unlock(&ktrace_mtx);
1241 vrele_count++;
1242 }
1243 PROC_UNLOCK(p);
1244 if (cred != NULL) {
1245 crfree(cred);
1246 cred = NULL;
1247 }
1248 }
1249 sx_sunlock(&allproc_lock);
1250
1251 while (vrele_count-- > 0)
1252 vrele(vp);
1253 }
1254
1255 /*
1256 * Return true if caller has permission to set the ktracing state
1257 * of target. Essentially, the target can't possess any
1258 * more permissions than the caller. KTRFAC_ROOT signifies that
1259 * root previously set the tracing status on the target process, and
1260 * so, only root may further change it.
1261 */
1262 static int
1263 ktrcanset(td, targetp)
1264 struct thread *td;
1265 struct proc *targetp;
1266 {
1267
1268 PROC_LOCK_ASSERT(targetp, MA_OWNED);
1269 if (targetp->p_traceflag & KTRFAC_ROOT &&
1270 priv_check(td, PRIV_KTRACE))
1271 return (0);
1272
1273 if (p_candebug(td, targetp) != 0)
1274 return (0);
1275
1276 return (1);
1277 }
1278
1279 #endif /* KTRACE */
Cache object: 61168bf5488a226e5196e6d74192d1da
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