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("$FreeBSD$");
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 TUNABLE_INT("kern.ktrace.genio_size", &ktr_geniosize);
137 SYSCTL_UINT(_kern_ktrace, OID_AUTO, genio_size, CTLFLAG_RW, &ktr_geniosize,
138 0, "Maximum size of genio event payload");
139
140 static int print_message = 1;
141 static struct mtx ktrace_mtx;
142 static struct sx ktrace_sx;
143
144 static void ktrace_init(void *dummy);
145 static int sysctl_kern_ktrace_request_pool(SYSCTL_HANDLER_ARGS);
146 static u_int ktrace_resize_pool(u_int oldsize, u_int newsize);
147 static struct ktr_request *ktr_getrequest_entered(struct thread *td, int type);
148 static struct ktr_request *ktr_getrequest(int type);
149 static void ktr_submitrequest(struct thread *td, struct ktr_request *req);
150 static void ktr_freeproc(struct proc *p, struct ucred **uc,
151 struct vnode **vp);
152 static void ktr_freerequest(struct ktr_request *req);
153 static void ktr_freerequest_locked(struct ktr_request *req);
154 static void ktr_writerequest(struct thread *td, struct ktr_request *req);
155 static int ktrcanset(struct thread *,struct proc *);
156 static int ktrsetchildren(struct thread *,struct proc *,int,int,struct vnode *);
157 static int ktrops(struct thread *,struct proc *,int,int,struct vnode *);
158 static void ktrprocctor_entered(struct thread *, struct proc *);
159
160 /*
161 * ktrace itself generates events, such as context switches, which we do not
162 * wish to trace. Maintain a flag, TDP_INKTRACE, on each thread to determine
163 * whether or not it is in a region where tracing of events should be
164 * suppressed.
165 */
166 static void
167 ktrace_enter(struct thread *td)
168 {
169
170 KASSERT(!(td->td_pflags & TDP_INKTRACE), ("ktrace_enter: flag set"));
171 td->td_pflags |= TDP_INKTRACE;
172 }
173
174 static void
175 ktrace_exit(struct thread *td)
176 {
177
178 KASSERT(td->td_pflags & TDP_INKTRACE, ("ktrace_exit: flag not set"));
179 td->td_pflags &= ~TDP_INKTRACE;
180 }
181
182 static void
183 ktrace_assert(struct thread *td)
184 {
185
186 KASSERT(td->td_pflags & TDP_INKTRACE, ("ktrace_assert: flag not set"));
187 }
188
189 static void
190 ktrace_init(void *dummy)
191 {
192 struct ktr_request *req;
193 int i;
194
195 mtx_init(&ktrace_mtx, "ktrace", NULL, MTX_DEF | MTX_QUIET);
196 sx_init(&ktrace_sx, "ktrace_sx");
197 STAILQ_INIT(&ktr_free);
198 for (i = 0; i < ktr_requestpool; i++) {
199 req = malloc(sizeof(struct ktr_request), M_KTRACE, M_WAITOK);
200 STAILQ_INSERT_HEAD(&ktr_free, req, ktr_list);
201 }
202 }
203 SYSINIT(ktrace_init, SI_SUB_KTRACE, SI_ORDER_ANY, ktrace_init, NULL);
204
205 static int
206 sysctl_kern_ktrace_request_pool(SYSCTL_HANDLER_ARGS)
207 {
208 struct thread *td;
209 u_int newsize, oldsize, wantsize;
210 int error;
211
212 /* Handle easy read-only case first to avoid warnings from GCC. */
213 if (!req->newptr) {
214 oldsize = ktr_requestpool;
215 return (SYSCTL_OUT(req, &oldsize, sizeof(u_int)));
216 }
217
218 error = SYSCTL_IN(req, &wantsize, sizeof(u_int));
219 if (error)
220 return (error);
221 td = curthread;
222 ktrace_enter(td);
223 oldsize = ktr_requestpool;
224 newsize = ktrace_resize_pool(oldsize, wantsize);
225 ktrace_exit(td);
226 error = SYSCTL_OUT(req, &oldsize, sizeof(u_int));
227 if (error)
228 return (error);
229 if (wantsize > oldsize && newsize < wantsize)
230 return (ENOSPC);
231 return (0);
232 }
233 SYSCTL_PROC(_kern_ktrace, OID_AUTO, request_pool, CTLTYPE_UINT|CTLFLAG_RW,
234 &ktr_requestpool, 0, sysctl_kern_ktrace_request_pool, "IU",
235 "Pool buffer size for ktrace(1)");
236
237 static u_int
238 ktrace_resize_pool(u_int oldsize, u_int newsize)
239 {
240 STAILQ_HEAD(, ktr_request) ktr_new;
241 struct ktr_request *req;
242 int bound;
243
244 print_message = 1;
245 bound = newsize - oldsize;
246 if (bound == 0)
247 return (ktr_requestpool);
248 if (bound < 0) {
249 mtx_lock(&ktrace_mtx);
250 /* Shrink pool down to newsize if possible. */
251 while (bound++ < 0) {
252 req = STAILQ_FIRST(&ktr_free);
253 if (req == NULL)
254 break;
255 STAILQ_REMOVE_HEAD(&ktr_free, ktr_list);
256 ktr_requestpool--;
257 free(req, M_KTRACE);
258 }
259 } else {
260 /* Grow pool up to newsize. */
261 STAILQ_INIT(&ktr_new);
262 while (bound-- > 0) {
263 req = malloc(sizeof(struct ktr_request), M_KTRACE,
264 M_WAITOK);
265 STAILQ_INSERT_HEAD(&ktr_new, req, ktr_list);
266 }
267 mtx_lock(&ktrace_mtx);
268 STAILQ_CONCAT(&ktr_free, &ktr_new);
269 ktr_requestpool += (newsize - oldsize);
270 }
271 mtx_unlock(&ktrace_mtx);
272 return (ktr_requestpool);
273 }
274
275 /* ktr_getrequest() assumes that ktr_comm[] is the same size as td_name[]. */
276 CTASSERT(sizeof(((struct ktr_header *)NULL)->ktr_comm) ==
277 (sizeof((struct thread *)NULL)->td_name));
278
279 static struct ktr_request *
280 ktr_getrequest_entered(struct thread *td, int type)
281 {
282 struct ktr_request *req;
283 struct proc *p = td->td_proc;
284 int pm;
285
286 mtx_lock(&ktrace_mtx);
287 if (!KTRCHECK(td, type)) {
288 mtx_unlock(&ktrace_mtx);
289 return (NULL);
290 }
291 req = STAILQ_FIRST(&ktr_free);
292 if (req != NULL) {
293 STAILQ_REMOVE_HEAD(&ktr_free, ktr_list);
294 req->ktr_header.ktr_type = type;
295 if (p->p_traceflag & KTRFAC_DROP) {
296 req->ktr_header.ktr_type |= KTR_DROP;
297 p->p_traceflag &= ~KTRFAC_DROP;
298 }
299 mtx_unlock(&ktrace_mtx);
300 microtime(&req->ktr_header.ktr_time);
301 req->ktr_header.ktr_pid = p->p_pid;
302 req->ktr_header.ktr_tid = td->td_tid;
303 bcopy(td->td_name, req->ktr_header.ktr_comm,
304 sizeof(req->ktr_header.ktr_comm));
305 req->ktr_buffer = NULL;
306 req->ktr_header.ktr_len = 0;
307 } else {
308 p->p_traceflag |= KTRFAC_DROP;
309 pm = print_message;
310 print_message = 0;
311 mtx_unlock(&ktrace_mtx);
312 if (pm)
313 printf("Out of ktrace request objects.\n");
314 }
315 return (req);
316 }
317
318 static struct ktr_request *
319 ktr_getrequest(int type)
320 {
321 struct thread *td = curthread;
322 struct ktr_request *req;
323
324 ktrace_enter(td);
325 req = ktr_getrequest_entered(td, type);
326 if (req == NULL)
327 ktrace_exit(td);
328
329 return (req);
330 }
331
332 /*
333 * Some trace generation environments don't permit direct access to VFS,
334 * such as during a context switch where sleeping is not allowed. Under these
335 * circumstances, queue a request to the thread to be written asynchronously
336 * later.
337 */
338 static void
339 ktr_enqueuerequest(struct thread *td, struct ktr_request *req)
340 {
341
342 mtx_lock(&ktrace_mtx);
343 STAILQ_INSERT_TAIL(&td->td_proc->p_ktr, req, ktr_list);
344 mtx_unlock(&ktrace_mtx);
345 }
346
347 /*
348 * Drain any pending ktrace records from the per-thread queue to disk. This
349 * is used both internally before committing other records, and also on
350 * system call return. We drain all the ones we can find at the time when
351 * drain is requested, but don't keep draining after that as those events
352 * may be approximately "after" the current event.
353 */
354 static void
355 ktr_drain(struct thread *td)
356 {
357 struct ktr_request *queued_req;
358 STAILQ_HEAD(, ktr_request) local_queue;
359
360 ktrace_assert(td);
361 sx_assert(&ktrace_sx, SX_XLOCKED);
362
363 STAILQ_INIT(&local_queue);
364
365 if (!STAILQ_EMPTY(&td->td_proc->p_ktr)) {
366 mtx_lock(&ktrace_mtx);
367 STAILQ_CONCAT(&local_queue, &td->td_proc->p_ktr);
368 mtx_unlock(&ktrace_mtx);
369
370 while ((queued_req = STAILQ_FIRST(&local_queue))) {
371 STAILQ_REMOVE_HEAD(&local_queue, ktr_list);
372 ktr_writerequest(td, queued_req);
373 ktr_freerequest(queued_req);
374 }
375 }
376 }
377
378 /*
379 * Submit a trace record for immediate commit to disk -- to be used only
380 * where entering VFS is OK. First drain any pending records that may have
381 * been cached in the thread.
382 */
383 static void
384 ktr_submitrequest(struct thread *td, struct ktr_request *req)
385 {
386
387 ktrace_assert(td);
388
389 sx_xlock(&ktrace_sx);
390 ktr_drain(td);
391 ktr_writerequest(td, req);
392 ktr_freerequest(req);
393 sx_xunlock(&ktrace_sx);
394 ktrace_exit(td);
395 }
396
397 static void
398 ktr_freerequest(struct ktr_request *req)
399 {
400
401 mtx_lock(&ktrace_mtx);
402 ktr_freerequest_locked(req);
403 mtx_unlock(&ktrace_mtx);
404 }
405
406 static void
407 ktr_freerequest_locked(struct ktr_request *req)
408 {
409
410 mtx_assert(&ktrace_mtx, MA_OWNED);
411 if (req->ktr_buffer != NULL)
412 free(req->ktr_buffer, M_KTRACE);
413 STAILQ_INSERT_HEAD(&ktr_free, req, ktr_list);
414 }
415
416 /*
417 * Disable tracing for a process and release all associated resources.
418 * The caller is responsible for releasing a reference on the returned
419 * vnode and credentials.
420 */
421 static void
422 ktr_freeproc(struct proc *p, struct ucred **uc, struct vnode **vp)
423 {
424 struct ktr_request *req;
425
426 PROC_LOCK_ASSERT(p, MA_OWNED);
427 mtx_assert(&ktrace_mtx, MA_OWNED);
428 *uc = p->p_tracecred;
429 p->p_tracecred = NULL;
430 if (vp != NULL)
431 *vp = p->p_tracevp;
432 p->p_tracevp = NULL;
433 p->p_traceflag = 0;
434 while ((req = STAILQ_FIRST(&p->p_ktr)) != NULL) {
435 STAILQ_REMOVE_HEAD(&p->p_ktr, ktr_list);
436 ktr_freerequest_locked(req);
437 }
438 }
439
440 void
441 ktrsyscall(code, narg, args)
442 int code, narg;
443 register_t args[];
444 {
445 struct ktr_request *req;
446 struct ktr_syscall *ktp;
447 size_t buflen;
448 char *buf = NULL;
449
450 buflen = sizeof(register_t) * narg;
451 if (buflen > 0) {
452 buf = malloc(buflen, M_KTRACE, M_WAITOK);
453 bcopy(args, buf, buflen);
454 }
455 req = ktr_getrequest(KTR_SYSCALL);
456 if (req == NULL) {
457 if (buf != NULL)
458 free(buf, M_KTRACE);
459 return;
460 }
461 ktp = &req->ktr_data.ktr_syscall;
462 ktp->ktr_code = code;
463 ktp->ktr_narg = narg;
464 if (buflen > 0) {
465 req->ktr_header.ktr_len = buflen;
466 req->ktr_buffer = buf;
467 }
468 ktr_submitrequest(curthread, req);
469 }
470
471 void
472 ktrsysret(code, error, retval)
473 int code, error;
474 register_t retval;
475 {
476 struct ktr_request *req;
477 struct ktr_sysret *ktp;
478
479 req = ktr_getrequest(KTR_SYSRET);
480 if (req == NULL)
481 return;
482 ktp = &req->ktr_data.ktr_sysret;
483 ktp->ktr_code = code;
484 ktp->ktr_error = error;
485 ktp->ktr_retval = ((error == 0) ? retval: 0); /* what about val2 ? */
486 ktr_submitrequest(curthread, req);
487 }
488
489 /*
490 * When a setuid process execs, disable tracing.
491 *
492 * XXX: We toss any pending asynchronous records.
493 */
494 void
495 ktrprocexec(struct proc *p, struct ucred **uc, struct vnode **vp)
496 {
497
498 PROC_LOCK_ASSERT(p, MA_OWNED);
499 mtx_lock(&ktrace_mtx);
500 ktr_freeproc(p, uc, vp);
501 mtx_unlock(&ktrace_mtx);
502 }
503
504 /*
505 * When a process exits, drain per-process asynchronous trace records
506 * and disable tracing.
507 */
508 void
509 ktrprocexit(struct thread *td)
510 {
511 struct ktr_request *req;
512 struct proc *p;
513 struct ucred *cred;
514 struct vnode *vp;
515
516 p = td->td_proc;
517 if (p->p_traceflag == 0)
518 return;
519
520 ktrace_enter(td);
521 req = ktr_getrequest_entered(td, KTR_PROCDTOR);
522 if (req != NULL)
523 ktr_enqueuerequest(td, req);
524 sx_xlock(&ktrace_sx);
525 ktr_drain(td);
526 sx_xunlock(&ktrace_sx);
527 PROC_LOCK(p);
528 mtx_lock(&ktrace_mtx);
529 ktr_freeproc(p, &cred, &vp);
530 mtx_unlock(&ktrace_mtx);
531 PROC_UNLOCK(p);
532 if (vp != NULL)
533 vrele(vp);
534 if (cred != NULL)
535 crfree(cred);
536 ktrace_exit(td);
537 }
538
539 static void
540 ktrprocctor_entered(struct thread *td, struct proc *p)
541 {
542 struct ktr_proc_ctor *ktp;
543 struct ktr_request *req;
544 struct thread *td2;
545
546 ktrace_assert(td);
547 td2 = FIRST_THREAD_IN_PROC(p);
548 req = ktr_getrequest_entered(td2, KTR_PROCCTOR);
549 if (req == NULL)
550 return;
551 ktp = &req->ktr_data.ktr_proc_ctor;
552 ktp->sv_flags = p->p_sysent->sv_flags;
553 ktr_enqueuerequest(td2, req);
554 }
555
556 void
557 ktrprocctor(struct proc *p)
558 {
559 struct thread *td = curthread;
560
561 if ((p->p_traceflag & KTRFAC_MASK) == 0)
562 return;
563
564 ktrace_enter(td);
565 ktrprocctor_entered(td, p);
566 ktrace_exit(td);
567 }
568
569 /*
570 * When a process forks, enable tracing in the new process if needed.
571 */
572 void
573 ktrprocfork(struct proc *p1, struct proc *p2)
574 {
575
576 PROC_LOCK(p1);
577 mtx_lock(&ktrace_mtx);
578 KASSERT(p2->p_tracevp == NULL, ("new process has a ktrace vnode"));
579 if (p1->p_traceflag & KTRFAC_INHERIT) {
580 p2->p_traceflag = p1->p_traceflag;
581 if ((p2->p_tracevp = p1->p_tracevp) != NULL) {
582 VREF(p2->p_tracevp);
583 KASSERT(p1->p_tracecred != NULL,
584 ("ktrace vnode with no cred"));
585 p2->p_tracecred = crhold(p1->p_tracecred);
586 }
587 }
588 mtx_unlock(&ktrace_mtx);
589 PROC_UNLOCK(p1);
590
591 ktrprocctor(p2);
592 }
593
594 /*
595 * When a thread returns, drain any asynchronous records generated by the
596 * system call.
597 */
598 void
599 ktruserret(struct thread *td)
600 {
601
602 ktrace_enter(td);
603 sx_xlock(&ktrace_sx);
604 ktr_drain(td);
605 sx_xunlock(&ktrace_sx);
606 ktrace_exit(td);
607 }
608
609 void
610 ktrnamei(path)
611 char *path;
612 {
613 struct ktr_request *req;
614 int namelen;
615 char *buf = NULL;
616
617 namelen = strlen(path);
618 if (namelen > 0) {
619 buf = malloc(namelen, M_KTRACE, M_WAITOK);
620 bcopy(path, buf, namelen);
621 }
622 req = ktr_getrequest(KTR_NAMEI);
623 if (req == NULL) {
624 if (buf != NULL)
625 free(buf, M_KTRACE);
626 return;
627 }
628 if (namelen > 0) {
629 req->ktr_header.ktr_len = namelen;
630 req->ktr_buffer = buf;
631 }
632 ktr_submitrequest(curthread, req);
633 }
634
635 void
636 ktrsysctl(name, namelen)
637 int *name;
638 u_int namelen;
639 {
640 struct ktr_request *req;
641 u_int mib[CTL_MAXNAME + 2];
642 char *mibname;
643 size_t mibnamelen;
644 int error;
645
646 /* Lookup name of mib. */
647 KASSERT(namelen <= CTL_MAXNAME, ("sysctl MIB too long"));
648 mib[0] = 0;
649 mib[1] = 1;
650 bcopy(name, mib + 2, namelen * sizeof(*name));
651 mibnamelen = 128;
652 mibname = malloc(mibnamelen, M_KTRACE, M_WAITOK);
653 error = kernel_sysctl(curthread, mib, namelen + 2, mibname, &mibnamelen,
654 NULL, 0, &mibnamelen, 0);
655 if (error) {
656 free(mibname, M_KTRACE);
657 return;
658 }
659 req = ktr_getrequest(KTR_SYSCTL);
660 if (req == NULL) {
661 free(mibname, M_KTRACE);
662 return;
663 }
664 req->ktr_header.ktr_len = mibnamelen;
665 req->ktr_buffer = mibname;
666 ktr_submitrequest(curthread, req);
667 }
668
669 void
670 ktrgenio(fd, rw, uio, error)
671 int fd;
672 enum uio_rw rw;
673 struct uio *uio;
674 int error;
675 {
676 struct ktr_request *req;
677 struct ktr_genio *ktg;
678 int datalen;
679 char *buf;
680
681 if (error) {
682 free(uio, M_IOV);
683 return;
684 }
685 uio->uio_offset = 0;
686 uio->uio_rw = UIO_WRITE;
687 datalen = MIN(uio->uio_resid, ktr_geniosize);
688 buf = malloc(datalen, M_KTRACE, M_WAITOK);
689 error = uiomove(buf, datalen, uio);
690 free(uio, M_IOV);
691 if (error) {
692 free(buf, M_KTRACE);
693 return;
694 }
695 req = ktr_getrequest(KTR_GENIO);
696 if (req == NULL) {
697 free(buf, M_KTRACE);
698 return;
699 }
700 ktg = &req->ktr_data.ktr_genio;
701 ktg->ktr_fd = fd;
702 ktg->ktr_rw = rw;
703 req->ktr_header.ktr_len = datalen;
704 req->ktr_buffer = buf;
705 ktr_submitrequest(curthread, req);
706 }
707
708 void
709 ktrpsig(sig, action, mask, code)
710 int sig;
711 sig_t action;
712 sigset_t *mask;
713 int code;
714 {
715 struct thread *td = curthread;
716 struct ktr_request *req;
717 struct ktr_psig *kp;
718
719 req = ktr_getrequest(KTR_PSIG);
720 if (req == NULL)
721 return;
722 kp = &req->ktr_data.ktr_psig;
723 kp->signo = (char)sig;
724 kp->action = action;
725 kp->mask = *mask;
726 kp->code = code;
727 ktr_enqueuerequest(td, req);
728 ktrace_exit(td);
729 }
730
731 void
732 ktrcsw(out, user, wmesg)
733 int out, user;
734 const char *wmesg;
735 {
736 struct thread *td = curthread;
737 struct ktr_request *req;
738 struct ktr_csw *kc;
739
740 req = ktr_getrequest(KTR_CSW);
741 if (req == NULL)
742 return;
743 kc = &req->ktr_data.ktr_csw;
744 kc->out = out;
745 kc->user = user;
746 if (wmesg != NULL)
747 strlcpy(kc->wmesg, wmesg, sizeof(kc->wmesg));
748 else
749 bzero(kc->wmesg, sizeof(kc->wmesg));
750 ktr_enqueuerequest(td, req);
751 ktrace_exit(td);
752 }
753
754 void
755 ktrstruct(name, data, datalen)
756 const char *name;
757 void *data;
758 size_t datalen;
759 {
760 struct ktr_request *req;
761 char *buf = NULL;
762 size_t buflen;
763
764 if (!data)
765 datalen = 0;
766 buflen = strlen(name) + 1 + datalen;
767 buf = malloc(buflen, M_KTRACE, M_WAITOK);
768 strcpy(buf, name);
769 bcopy(data, buf + strlen(name) + 1, datalen);
770 if ((req = ktr_getrequest(KTR_STRUCT)) == NULL) {
771 free(buf, M_KTRACE);
772 return;
773 }
774 req->ktr_buffer = buf;
775 req->ktr_header.ktr_len = buflen;
776 ktr_submitrequest(curthread, req);
777 }
778
779 void
780 ktrcapfail(type, needed, held)
781 enum ktr_cap_fail_type type;
782 const cap_rights_t *needed;
783 const cap_rights_t *held;
784 {
785 struct thread *td = curthread;
786 struct ktr_request *req;
787 struct ktr_cap_fail *kcf;
788
789 req = ktr_getrequest(KTR_CAPFAIL);
790 if (req == NULL)
791 return;
792 kcf = &req->ktr_data.ktr_cap_fail;
793 kcf->cap_type = type;
794 if (needed != NULL)
795 kcf->cap_needed = *needed;
796 else
797 cap_rights_init(&kcf->cap_needed);
798 if (held != NULL)
799 kcf->cap_held = *held;
800 else
801 cap_rights_init(&kcf->cap_held);
802 ktr_enqueuerequest(td, req);
803 ktrace_exit(td);
804 }
805
806 void
807 ktrfault(vaddr, type)
808 vm_offset_t vaddr;
809 int type;
810 {
811 struct thread *td = curthread;
812 struct ktr_request *req;
813 struct ktr_fault *kf;
814
815 req = ktr_getrequest(KTR_FAULT);
816 if (req == NULL)
817 return;
818 kf = &req->ktr_data.ktr_fault;
819 kf->vaddr = vaddr;
820 kf->type = type;
821 ktr_enqueuerequest(td, req);
822 ktrace_exit(td);
823 }
824
825 void
826 ktrfaultend(result)
827 int result;
828 {
829 struct thread *td = curthread;
830 struct ktr_request *req;
831 struct ktr_faultend *kf;
832
833 req = ktr_getrequest(KTR_FAULTEND);
834 if (req == NULL)
835 return;
836 kf = &req->ktr_data.ktr_faultend;
837 kf->result = result;
838 ktr_enqueuerequest(td, req);
839 ktrace_exit(td);
840 }
841 #endif /* KTRACE */
842
843 /* Interface and common routines */
844
845 #ifndef _SYS_SYSPROTO_H_
846 struct ktrace_args {
847 char *fname;
848 int ops;
849 int facs;
850 int pid;
851 };
852 #endif
853 /* ARGSUSED */
854 int
855 sys_ktrace(td, uap)
856 struct thread *td;
857 register struct ktrace_args *uap;
858 {
859 #ifdef KTRACE
860 register struct vnode *vp = NULL;
861 register struct proc *p;
862 struct pgrp *pg;
863 int facs = uap->facs & ~KTRFAC_ROOT;
864 int ops = KTROP(uap->ops);
865 int descend = uap->ops & KTRFLAG_DESCEND;
866 int nfound, ret = 0;
867 int flags, error = 0;
868 struct nameidata nd;
869 struct ucred *cred;
870
871 /*
872 * Need something to (un)trace.
873 */
874 if (ops != KTROP_CLEARFILE && facs == 0)
875 return (EINVAL);
876
877 ktrace_enter(td);
878 if (ops != KTROP_CLEAR) {
879 /*
880 * an operation which requires a file argument.
881 */
882 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->fname, td);
883 flags = FREAD | FWRITE | O_NOFOLLOW;
884 error = vn_open(&nd, &flags, 0, NULL);
885 if (error) {
886 ktrace_exit(td);
887 return (error);
888 }
889 NDFREE(&nd, NDF_ONLY_PNBUF);
890 vp = nd.ni_vp;
891 VOP_UNLOCK(vp, 0);
892 if (vp->v_type != VREG) {
893 (void) vn_close(vp, FREAD|FWRITE, td->td_ucred, td);
894 ktrace_exit(td);
895 return (EACCES);
896 }
897 }
898 /*
899 * Clear all uses of the tracefile.
900 */
901 if (ops == KTROP_CLEARFILE) {
902 int vrele_count;
903
904 vrele_count = 0;
905 sx_slock(&allproc_lock);
906 FOREACH_PROC_IN_SYSTEM(p) {
907 PROC_LOCK(p);
908 if (p->p_tracevp == vp) {
909 if (ktrcanset(td, p)) {
910 mtx_lock(&ktrace_mtx);
911 ktr_freeproc(p, &cred, NULL);
912 mtx_unlock(&ktrace_mtx);
913 vrele_count++;
914 crfree(cred);
915 } else
916 error = EPERM;
917 }
918 PROC_UNLOCK(p);
919 }
920 sx_sunlock(&allproc_lock);
921 if (vrele_count > 0) {
922 while (vrele_count-- > 0)
923 vrele(vp);
924 }
925 goto done;
926 }
927 /*
928 * do it
929 */
930 sx_slock(&proctree_lock);
931 if (uap->pid < 0) {
932 /*
933 * by process group
934 */
935 pg = pgfind(-uap->pid);
936 if (pg == NULL) {
937 sx_sunlock(&proctree_lock);
938 error = ESRCH;
939 goto done;
940 }
941 /*
942 * ktrops() may call vrele(). Lock pg_members
943 * by the proctree_lock rather than pg_mtx.
944 */
945 PGRP_UNLOCK(pg);
946 nfound = 0;
947 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
948 PROC_LOCK(p);
949 if (p->p_state == PRS_NEW ||
950 p_cansee(td, p) != 0) {
951 PROC_UNLOCK(p);
952 continue;
953 }
954 nfound++;
955 if (descend)
956 ret |= ktrsetchildren(td, p, ops, facs, vp);
957 else
958 ret |= ktrops(td, p, ops, facs, vp);
959 }
960 if (nfound == 0) {
961 sx_sunlock(&proctree_lock);
962 error = ESRCH;
963 goto done;
964 }
965 } else {
966 /*
967 * by pid
968 */
969 p = pfind(uap->pid);
970 if (p == NULL)
971 error = ESRCH;
972 else
973 error = p_cansee(td, p);
974 if (error) {
975 if (p != NULL)
976 PROC_UNLOCK(p);
977 sx_sunlock(&proctree_lock);
978 goto done;
979 }
980 if (descend)
981 ret |= ktrsetchildren(td, p, ops, facs, vp);
982 else
983 ret |= ktrops(td, p, ops, facs, vp);
984 }
985 sx_sunlock(&proctree_lock);
986 if (!ret)
987 error = EPERM;
988 done:
989 if (vp != NULL)
990 (void) vn_close(vp, FWRITE, td->td_ucred, td);
991 ktrace_exit(td);
992 return (error);
993 #else /* !KTRACE */
994 return (ENOSYS);
995 #endif /* KTRACE */
996 }
997
998 /* ARGSUSED */
999 int
1000 sys_utrace(td, uap)
1001 struct thread *td;
1002 register struct utrace_args *uap;
1003 {
1004
1005 #ifdef KTRACE
1006 struct ktr_request *req;
1007 void *cp;
1008 int error;
1009
1010 if (!KTRPOINT(td, KTR_USER))
1011 return (0);
1012 if (uap->len > KTR_USER_MAXLEN)
1013 return (EINVAL);
1014 cp = malloc(uap->len, M_KTRACE, M_WAITOK);
1015 error = copyin(uap->addr, cp, uap->len);
1016 if (error) {
1017 free(cp, M_KTRACE);
1018 return (error);
1019 }
1020 req = ktr_getrequest(KTR_USER);
1021 if (req == NULL) {
1022 free(cp, M_KTRACE);
1023 return (ENOMEM);
1024 }
1025 req->ktr_buffer = cp;
1026 req->ktr_header.ktr_len = uap->len;
1027 ktr_submitrequest(td, req);
1028 return (0);
1029 #else /* !KTRACE */
1030 return (ENOSYS);
1031 #endif /* KTRACE */
1032 }
1033
1034 #ifdef KTRACE
1035 static int
1036 ktrops(td, p, ops, facs, vp)
1037 struct thread *td;
1038 struct proc *p;
1039 int ops, facs;
1040 struct vnode *vp;
1041 {
1042 struct vnode *tracevp = NULL;
1043 struct ucred *tracecred = NULL;
1044
1045 PROC_LOCK_ASSERT(p, MA_OWNED);
1046 if (!ktrcanset(td, p)) {
1047 PROC_UNLOCK(p);
1048 return (0);
1049 }
1050 if (p->p_flag & P_WEXIT) {
1051 /* If the process is exiting, just ignore it. */
1052 PROC_UNLOCK(p);
1053 return (1);
1054 }
1055 mtx_lock(&ktrace_mtx);
1056 if (ops == KTROP_SET) {
1057 if (p->p_tracevp != vp) {
1058 /*
1059 * if trace file already in use, relinquish below
1060 */
1061 tracevp = p->p_tracevp;
1062 VREF(vp);
1063 p->p_tracevp = vp;
1064 }
1065 if (p->p_tracecred != td->td_ucred) {
1066 tracecred = p->p_tracecred;
1067 p->p_tracecred = crhold(td->td_ucred);
1068 }
1069 p->p_traceflag |= facs;
1070 if (priv_check(td, PRIV_KTRACE) == 0)
1071 p->p_traceflag |= KTRFAC_ROOT;
1072 } else {
1073 /* KTROP_CLEAR */
1074 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0)
1075 /* no more tracing */
1076 ktr_freeproc(p, &tracecred, &tracevp);
1077 }
1078 mtx_unlock(&ktrace_mtx);
1079 if ((p->p_traceflag & KTRFAC_MASK) != 0)
1080 ktrprocctor_entered(td, p);
1081 PROC_UNLOCK(p);
1082 if (tracevp != NULL)
1083 vrele(tracevp);
1084 if (tracecred != NULL)
1085 crfree(tracecred);
1086
1087 return (1);
1088 }
1089
1090 static int
1091 ktrsetchildren(td, top, ops, facs, vp)
1092 struct thread *td;
1093 struct proc *top;
1094 int ops, facs;
1095 struct vnode *vp;
1096 {
1097 register struct proc *p;
1098 register int ret = 0;
1099
1100 p = top;
1101 PROC_LOCK_ASSERT(p, MA_OWNED);
1102 sx_assert(&proctree_lock, SX_LOCKED);
1103 for (;;) {
1104 ret |= ktrops(td, p, ops, facs, vp);
1105 /*
1106 * If this process has children, descend to them next,
1107 * otherwise do any siblings, and if done with this level,
1108 * follow back up the tree (but not past top).
1109 */
1110 if (!LIST_EMPTY(&p->p_children))
1111 p = LIST_FIRST(&p->p_children);
1112 else for (;;) {
1113 if (p == top)
1114 return (ret);
1115 if (LIST_NEXT(p, p_sibling)) {
1116 p = LIST_NEXT(p, p_sibling);
1117 break;
1118 }
1119 p = p->p_pptr;
1120 }
1121 PROC_LOCK(p);
1122 }
1123 /*NOTREACHED*/
1124 }
1125
1126 static void
1127 ktr_writerequest(struct thread *td, struct ktr_request *req)
1128 {
1129 struct ktr_header *kth;
1130 struct vnode *vp;
1131 struct proc *p;
1132 struct ucred *cred;
1133 struct uio auio;
1134 struct iovec aiov[3];
1135 struct mount *mp;
1136 int datalen, buflen, vrele_count;
1137 int error;
1138
1139 /*
1140 * We hold the vnode and credential for use in I/O in case ktrace is
1141 * disabled on the process as we write out the request.
1142 *
1143 * XXXRW: This is not ideal: we could end up performing a write after
1144 * the vnode has been closed.
1145 */
1146 mtx_lock(&ktrace_mtx);
1147 vp = td->td_proc->p_tracevp;
1148 cred = td->td_proc->p_tracecred;
1149
1150 /*
1151 * If vp is NULL, the vp has been cleared out from under this
1152 * request, so just drop it. Make sure the credential and vnode are
1153 * in sync: we should have both or neither.
1154 */
1155 if (vp == NULL) {
1156 KASSERT(cred == NULL, ("ktr_writerequest: cred != NULL"));
1157 mtx_unlock(&ktrace_mtx);
1158 return;
1159 }
1160 VREF(vp);
1161 KASSERT(cred != NULL, ("ktr_writerequest: cred == NULL"));
1162 crhold(cred);
1163 mtx_unlock(&ktrace_mtx);
1164
1165 kth = &req->ktr_header;
1166 KASSERT(((u_short)kth->ktr_type & ~KTR_DROP) <
1167 sizeof(data_lengths) / sizeof(data_lengths[0]),
1168 ("data_lengths array overflow"));
1169 datalen = data_lengths[(u_short)kth->ktr_type & ~KTR_DROP];
1170 buflen = kth->ktr_len;
1171 auio.uio_iov = &aiov[0];
1172 auio.uio_offset = 0;
1173 auio.uio_segflg = UIO_SYSSPACE;
1174 auio.uio_rw = UIO_WRITE;
1175 aiov[0].iov_base = (caddr_t)kth;
1176 aiov[0].iov_len = sizeof(struct ktr_header);
1177 auio.uio_resid = sizeof(struct ktr_header);
1178 auio.uio_iovcnt = 1;
1179 auio.uio_td = td;
1180 if (datalen != 0) {
1181 aiov[1].iov_base = (caddr_t)&req->ktr_data;
1182 aiov[1].iov_len = datalen;
1183 auio.uio_resid += datalen;
1184 auio.uio_iovcnt++;
1185 kth->ktr_len += datalen;
1186 }
1187 if (buflen != 0) {
1188 KASSERT(req->ktr_buffer != NULL, ("ktrace: nothing to write"));
1189 aiov[auio.uio_iovcnt].iov_base = req->ktr_buffer;
1190 aiov[auio.uio_iovcnt].iov_len = buflen;
1191 auio.uio_resid += buflen;
1192 auio.uio_iovcnt++;
1193 }
1194
1195 vn_start_write(vp, &mp, V_WAIT);
1196 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1197 #ifdef MAC
1198 error = mac_vnode_check_write(cred, NOCRED, vp);
1199 if (error == 0)
1200 #endif
1201 error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, cred);
1202 VOP_UNLOCK(vp, 0);
1203 vn_finished_write(mp);
1204 crfree(cred);
1205 if (!error) {
1206 vrele(vp);
1207 return;
1208 }
1209
1210 /*
1211 * If error encountered, give up tracing on this vnode. We defer
1212 * all the vrele()'s on the vnode until after we are finished walking
1213 * the various lists to avoid needlessly holding locks.
1214 * NB: at this point we still hold the vnode reference that must
1215 * not go away as we need the valid vnode to compare with. Thus let
1216 * vrele_count start at 1 and the reference will be freed
1217 * by the loop at the end after our last use of vp.
1218 */
1219 log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n",
1220 error);
1221 vrele_count = 1;
1222 /*
1223 * First, clear this vnode from being used by any processes in the
1224 * system.
1225 * XXX - If one process gets an EPERM writing to the vnode, should
1226 * we really do this? Other processes might have suitable
1227 * credentials for the operation.
1228 */
1229 cred = NULL;
1230 sx_slock(&allproc_lock);
1231 FOREACH_PROC_IN_SYSTEM(p) {
1232 PROC_LOCK(p);
1233 if (p->p_tracevp == vp) {
1234 mtx_lock(&ktrace_mtx);
1235 ktr_freeproc(p, &cred, NULL);
1236 mtx_unlock(&ktrace_mtx);
1237 vrele_count++;
1238 }
1239 PROC_UNLOCK(p);
1240 if (cred != NULL) {
1241 crfree(cred);
1242 cred = NULL;
1243 }
1244 }
1245 sx_sunlock(&allproc_lock);
1246
1247 while (vrele_count-- > 0)
1248 vrele(vp);
1249 }
1250
1251 /*
1252 * Return true if caller has permission to set the ktracing state
1253 * of target. Essentially, the target can't possess any
1254 * more permissions than the caller. KTRFAC_ROOT signifies that
1255 * root previously set the tracing status on the target process, and
1256 * so, only root may further change it.
1257 */
1258 static int
1259 ktrcanset(td, targetp)
1260 struct thread *td;
1261 struct proc *targetp;
1262 {
1263
1264 PROC_LOCK_ASSERT(targetp, MA_OWNED);
1265 if (targetp->p_traceflag & KTRFAC_ROOT &&
1266 priv_check(td, PRIV_KTRACE))
1267 return (0);
1268
1269 if (p_candebug(td, targetp) != 0)
1270 return (0);
1271
1272 return (1);
1273 }
1274
1275 #endif /* KTRACE */
Cache object: 05f0a201318e80d24fbb8b8222d366d4
|