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[dragonfly.git] / sys / kern / kern_ktrace.c
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1/*
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. 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 * $FreeBSD: src/sys/kern/kern_ktrace.c,v 1.35.2.6 2002/07/05 22:36:38 darrenr Exp $
35 */
36
37#include "opt_ktrace.h"
38
39#include <sys/param.h>
40#include <sys/systm.h>
41#include <sys/sysproto.h>
42#include <sys/kernel.h>
43#include <sys/proc.h>
44#include <sys/fcntl.h>
45#include <sys/lock.h>
46#include <sys/namei.h>
47#include <sys/vnode.h>
48#include <sys/ktrace.h>
49#include <sys/malloc.h>
50#include <sys/syslog.h>
51#include <sys/sysent.h>
52
53#include <vm/vm_zone.h>
54static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE");
55
56#ifdef KTRACE
57static struct ktr_header *ktrgetheader __P((int type));
58static void ktrwrite __P((struct vnode *, struct ktr_header *, struct uio *));
59static int ktrcanset __P((struct proc *,struct proc *));
60static int ktrsetchildren __P((struct proc *,struct proc *,int,int,struct vnode *));
61static int ktrops __P((struct proc *,struct proc *,int,int,struct vnode *));
62
63
64static struct ktr_header *
65ktrgetheader(type)
66 int type;
67{
68 register struct ktr_header *kth;
69 struct proc *p = curproc; /* XXX */
70
71 MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header),
72 M_KTRACE, M_WAITOK);
73 kth->ktr_type = type;
74 microtime(&kth->ktr_time);
75 kth->ktr_pid = p->p_pid;
76 bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN + 1);
77 return (kth);
78}
79
80void
81ktrsyscall(vp, code, narg, args)
82 struct vnode *vp;
83 int code, narg;
84 register_t args[];
85{
86 struct ktr_header *kth;
87 struct ktr_syscall *ktp;
88 register int len = offsetof(struct ktr_syscall, ktr_args) +
89 (narg * sizeof(register_t));
90 struct proc *p = curproc; /* XXX */
91 register_t *argp;
92 int i;
93
94 p->p_traceflag |= KTRFAC_ACTIVE;
95 kth = ktrgetheader(KTR_SYSCALL);
96 MALLOC(ktp, struct ktr_syscall *, len, M_KTRACE, M_WAITOK);
97 ktp->ktr_code = code;
98 ktp->ktr_narg = narg;
99 argp = &ktp->ktr_args[0];
100 for (i = 0; i < narg; i++)
101 *argp++ = args[i];
102 kth->ktr_buf = (caddr_t)ktp;
103 kth->ktr_len = len;
104 ktrwrite(vp, kth, NULL);
105 FREE(ktp, M_KTRACE);
106 FREE(kth, M_KTRACE);
107 p->p_traceflag &= ~KTRFAC_ACTIVE;
108}
109
110void
111ktrsysret(vp, code, error, retval)
112 struct vnode *vp;
113 int code, error;
114 register_t retval;
115{
116 struct ktr_header *kth;
117 struct ktr_sysret ktp;
118 struct proc *p = curproc; /* XXX */
119
120 p->p_traceflag |= KTRFAC_ACTIVE;
121 kth = ktrgetheader(KTR_SYSRET);
122 ktp.ktr_code = code;
123 ktp.ktr_error = error;
124 ktp.ktr_retval = retval; /* what about val2 ? */
125
126 kth->ktr_buf = (caddr_t)&ktp;
127 kth->ktr_len = sizeof(struct ktr_sysret);
128
129 ktrwrite(vp, kth, NULL);
130 FREE(kth, M_KTRACE);
131 p->p_traceflag &= ~KTRFAC_ACTIVE;
132}
133
134void
135ktrnamei(vp, path)
136 struct vnode *vp;
137 char *path;
138{
139 struct ktr_header *kth;
140 struct proc *p = curproc; /* XXX */
141
142 /*
143 * don't let vp get ripped out from under us
144 */
145 if (vp)
146 VREF(vp);
147 p->p_traceflag |= KTRFAC_ACTIVE;
148 kth = ktrgetheader(KTR_NAMEI);
149 kth->ktr_len = strlen(path);
150 kth->ktr_buf = path;
151
152 ktrwrite(vp, kth, NULL);
153 if (vp)
154 vrele(vp);
155 FREE(kth, M_KTRACE);
156 p->p_traceflag &= ~KTRFAC_ACTIVE;
157}
158
159void
160ktrgenio(vp, fd, rw, uio, error)
161 struct vnode *vp;
162 int fd;
163 enum uio_rw rw;
164 struct uio *uio;
165 int error;
166{
167 struct ktr_header *kth;
168 struct ktr_genio ktg;
169 struct proc *p = curproc; /* XXX */
170
171 if (error)
172 return;
173 /*
174 * don't let p_tracep get ripped out from under us
175 */
176 if (vp)
177 VREF(vp);
178 p->p_traceflag |= KTRFAC_ACTIVE;
179 kth = ktrgetheader(KTR_GENIO);
180 ktg.ktr_fd = fd;
181 ktg.ktr_rw = rw;
182 kth->ktr_buf = (caddr_t)&ktg;
183 kth->ktr_len = sizeof(struct ktr_genio);
184 uio->uio_offset = 0;
185 uio->uio_rw = UIO_WRITE;
186
187 ktrwrite(vp, kth, uio);
188 if (vp)
189 vrele(vp);
190 FREE(kth, M_KTRACE);
191 p->p_traceflag &= ~KTRFAC_ACTIVE;
192}
193
194void
195ktrpsig(vp, sig, action, mask, code)
196 struct vnode *vp;
197 int sig;
198 sig_t action;
199 sigset_t *mask;
200 int code;
201{
202 struct ktr_header *kth;
203 struct ktr_psig kp;
204 struct proc *p = curproc; /* XXX */
205
206 /*
207 * don't let vp get ripped out from under us
208 */
209 if (vp)
210 VREF(vp);
211 p->p_traceflag |= KTRFAC_ACTIVE;
212 kth = ktrgetheader(KTR_PSIG);
213 kp.signo = (char)sig;
214 kp.action = action;
215 kp.mask = *mask;
216 kp.code = code;
217 kth->ktr_buf = (caddr_t)&kp;
218 kth->ktr_len = sizeof (struct ktr_psig);
219
220 ktrwrite(vp, kth, NULL);
221 if (vp)
222 vrele(vp);
223 FREE(kth, M_KTRACE);
224 p->p_traceflag &= ~KTRFAC_ACTIVE;
225}
226
227void
228ktrcsw(vp, out, user)
229 struct vnode *vp;
230 int out, user;
231{
232 struct ktr_header *kth;
233 struct ktr_csw kc;
234 struct proc *p = curproc; /* XXX */
235
236 /*
237 * don't let vp get ripped out from under us
238 */
239 if (vp)
240 VREF(vp);
241 p->p_traceflag |= KTRFAC_ACTIVE;
242 kth = ktrgetheader(KTR_CSW);
243 kc.out = out;
244 kc.user = user;
245 kth->ktr_buf = (caddr_t)&kc;
246 kth->ktr_len = sizeof (struct ktr_csw);
247
248 ktrwrite(vp, kth, NULL);
249 if (vp)
250 vrele(vp);
251 FREE(kth, M_KTRACE);
252 p->p_traceflag &= ~KTRFAC_ACTIVE;
253}
254#endif
255
256/* Interface and common routines */
257
258/*
259 * ktrace system call
260 */
261#ifndef _SYS_SYSPROTO_H_
262struct ktrace_args {
263 char *fname;
264 int ops;
265 int facs;
266 int pid;
267};
268#endif
269/* ARGSUSED */
270int
271ktrace(curp, uap)
272 struct proc *curp;
273 register struct ktrace_args *uap;
274{
275#ifdef KTRACE
276 register struct vnode *vp = NULL;
277 register struct proc *p;
278 struct pgrp *pg;
279 int facs = uap->facs & ~KTRFAC_ROOT;
280 int ops = KTROP(uap->ops);
281 int descend = uap->ops & KTRFLAG_DESCEND;
282 int ret = 0;
283 int error = 0;
284 struct nameidata nd;
285
286 curp->p_traceflag |= KTRFAC_ACTIVE;
287 if (ops != KTROP_CLEAR) {
288 /*
289 * an operation which requires a file argument.
290 */
291 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->fname, curp);
292 error = vn_open(&nd, FREAD|FWRITE|O_NOFOLLOW, 0);
293 if (error) {
294 curp->p_traceflag &= ~KTRFAC_ACTIVE;
295 return (error);
296 }
297 NDFREE(&nd, NDF_ONLY_PNBUF);
298 vp = nd.ni_vp;
299 VOP_UNLOCK(vp, 0, curp);
300 if (vp->v_type != VREG) {
301 (void) vn_close(vp, FREAD|FWRITE, curp->p_ucred, curp);
302 curp->p_traceflag &= ~KTRFAC_ACTIVE;
303 return (EACCES);
304 }
305 }
306 /*
307 * Clear all uses of the tracefile. XXX umm, what happens to the
308 * loop if vn_close() blocks?
309 */
310 if (ops == KTROP_CLEARFILE) {
311 LIST_FOREACH(p, &allproc, p_list) {
312 if (p->p_tracep == vp) {
313 if (ktrcanset(curp, p) && p->p_tracep == vp) {
314 p->p_tracep = NULL;
315 p->p_traceflag = 0;
316 (void) vn_close(vp, FREAD|FWRITE,
317 p->p_ucred, p);
318 } else {
319 error = EPERM;
320 }
321 }
322 }
323 goto done;
324 }
325 /*
326 * need something to (un)trace (XXX - why is this here?)
327 */
328 if (!facs) {
329 error = EINVAL;
330 goto done;
331 }
332 /*
333 * do it
334 */
335 if (uap->pid < 0) {
336 /*
337 * by process group
338 */
339 pg = pgfind(-uap->pid);
340 if (pg == NULL) {
341 error = ESRCH;
342 goto done;
343 }
344 LIST_FOREACH(p, &pg->pg_members, p_pglist)
345 if (descend)
346 ret |= ktrsetchildren(curp, p, ops, facs, vp);
347 else
348 ret |= ktrops(curp, p, ops, facs, vp);
349
350 } else {
351 /*
352 * by pid
353 */
354 p = pfind(uap->pid);
355 if (p == NULL) {
356 error = ESRCH;
357 goto done;
358 }
359 if (descend)
360 ret |= ktrsetchildren(curp, p, ops, facs, vp);
361 else
362 ret |= ktrops(curp, p, ops, facs, vp);
363 }
364 if (!ret)
365 error = EPERM;
366done:
367 if (vp != NULL)
368 (void) vn_close(vp, FWRITE, curp->p_ucred, curp);
369 curp->p_traceflag &= ~KTRFAC_ACTIVE;
370 return (error);
371#else
372 return ENOSYS;
373#endif
374}
375
376/*
377 * utrace system call
378 */
379/* ARGSUSED */
380int
381utrace(curp, uap)
382 struct proc *curp;
383 register struct utrace_args *uap;
384{
385#ifdef KTRACE
386 struct ktr_header *kth;
387 struct proc *p = curproc; /* XXX */
388 struct vnode *vp;
389 register caddr_t cp;
390
391 if (!KTRPOINT(p, KTR_USER))
392 return (0);
393 if (SCARG(uap, len) > KTR_USER_MAXLEN)
394 return (EINVAL);
395 p->p_traceflag |= KTRFAC_ACTIVE;
396 /*
397 * don't let p_tracep get ripped out from under us while we are
398 * writing.
399 */
400 if ((vp = p->p_tracep) != NULL)
401 VREF(vp);
402 kth = ktrgetheader(KTR_USER);
403 MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK);
404 if (!copyin(uap->addr, cp, uap->len)) {
405 kth->ktr_buf = cp;
406 kth->ktr_len = uap->len;
407 ktrwrite(vp, kth, NULL);
408 }
409 if (vp)
410 vrele(vp);
411 FREE(kth, M_KTRACE);
412 FREE(cp, M_KTRACE);
413 p->p_traceflag &= ~KTRFAC_ACTIVE;
414
415 return (0);
416#else
417 return (ENOSYS);
418#endif
419}
420
421#ifdef KTRACE
422static int
423ktrops(curp, p, ops, facs, vp)
424 struct proc *p, *curp;
425 int ops, facs;
426 struct vnode *vp;
427{
428
429 if (!ktrcanset(curp, p))
430 return (0);
431 if (ops == KTROP_SET) {
432 if (p->p_tracep != vp) {
433 struct vnode *vtmp;
434
435 /*
436 * if trace file already in use, relinquish
437 */
438 VREF(vp);
439 while ((vtmp = p->p_tracep) != NULL) {
440 p->p_tracep = NULL;
441 vrele(vtmp);
442 }
443 p->p_tracep = vp;
444 }
445 p->p_traceflag |= facs;
446 if (curp->p_ucred->cr_uid == 0)
447 p->p_traceflag |= KTRFAC_ROOT;
448 } else {
449 /* KTROP_CLEAR */
450 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
451 struct vnode *vtmp;
452
453 /* no more tracing */
454 p->p_traceflag = 0;
455 if ((vtmp = p->p_tracep) != NULL) {
456 p->p_tracep = NULL;
457 vrele(vtmp);
458 }
459 }
460 }
461
462 return (1);
463}
464
465static int
466ktrsetchildren(curp, top, ops, facs, vp)
467 struct proc *curp, *top;
468 int ops, facs;
469 struct vnode *vp;
470{
471 register struct proc *p;
472 register int ret = 0;
473
474 p = top;
475 for (;;) {
476 ret |= ktrops(curp, p, ops, facs, vp);
477 /*
478 * If this process has children, descend to them next,
479 * otherwise do any siblings, and if done with this level,
480 * follow back up the tree (but not past top).
481 */
482 if (!LIST_EMPTY(&p->p_children))
483 p = LIST_FIRST(&p->p_children);
484 else for (;;) {
485 if (p == top)
486 return (ret);
487 if (LIST_NEXT(p, p_sibling)) {
488 p = LIST_NEXT(p, p_sibling);
489 break;
490 }
491 p = p->p_pptr;
492 }
493 }
494 /*NOTREACHED*/
495}
496
497static void
498ktrwrite(vp, kth, uio)
499 struct vnode *vp;
500 register struct ktr_header *kth;
501 struct uio *uio;
502{
503 struct uio auio;
504 struct iovec aiov[2];
505 register struct proc *p = curproc; /* XXX */
506 int error;
507
508 if (vp == NULL)
509 return;
510 auio.uio_iov = &aiov[0];
511 auio.uio_offset = 0;
512 auio.uio_segflg = UIO_SYSSPACE;
513 auio.uio_rw = UIO_WRITE;
514 aiov[0].iov_base = (caddr_t)kth;
515 aiov[0].iov_len = sizeof(struct ktr_header);
516 auio.uio_resid = sizeof(struct ktr_header);
517 auio.uio_iovcnt = 1;
518 auio.uio_procp = curproc;
519 if (kth->ktr_len > 0) {
520 auio.uio_iovcnt++;
521 aiov[1].iov_base = kth->ktr_buf;
522 aiov[1].iov_len = kth->ktr_len;
523 auio.uio_resid += kth->ktr_len;
524 if (uio != NULL)
525 kth->ktr_len += uio->uio_resid;
526 }
527 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
528 (void)VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
529 error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, p->p_ucred);
530 if (error == 0 && uio != NULL) {
531 (void)VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
532 error = VOP_WRITE(vp, uio, IO_UNIT | IO_APPEND, p->p_ucred);
533 }
534 VOP_UNLOCK(vp, 0, p);
535 if (!error)
536 return;
537 /*
538 * If error encountered, give up tracing on this vnode. XXX what
539 * happens to the loop if vrele() blocks?
540 */
541 log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n",
542 error);
543 LIST_FOREACH(p, &allproc, p_list) {
544 if (p->p_tracep == vp) {
545 p->p_tracep = NULL;
546 p->p_traceflag = 0;
547 vrele(vp);
548 }
549 }
550}
551
552/*
553 * Return true if caller has permission to set the ktracing state
554 * of target. Essentially, the target can't possess any
555 * more permissions than the caller. KTRFAC_ROOT signifies that
556 * root previously set the tracing status on the target process, and
557 * so, only root may further change it.
558 *
559 * TODO: check groups. use caller effective gid.
560 */
561static int
562ktrcanset(callp, targetp)
563 struct proc *callp, *targetp;
564{
565 register struct pcred *caller = callp->p_cred;
566 register struct pcred *target = targetp->p_cred;
567
568 if (!PRISON_CHECK(callp, targetp))
569 return (0);
570 if ((caller->pc_ucred->cr_uid == target->p_ruid &&
571 target->p_ruid == target->p_svuid &&
572 caller->p_rgid == target->p_rgid && /* XXX */
573 target->p_rgid == target->p_svgid &&
574 (targetp->p_traceflag & KTRFAC_ROOT) == 0 &&
575 (targetp->p_flag & P_SUGID) == 0) ||
576 caller->pc_ucred->cr_uid == 0)
577 return (1);
578
579 return (0);
580}
581
582#endif /* KTRACE */