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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 * $DragonFly: src/sys/kern/kern_ktrace.c,v 1.7 2003/07/26 19:42:11 rob Exp $
38 #include "opt_ktrace.h"
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/sysproto.h>
43 #include <sys/kernel.h>
45 #include <sys/fcntl.h>
47 #include <sys/namei.h>
48 #include <sys/vnode.h>
49 #include <sys/ktrace.h>
50 #include <sys/malloc.h>
51 #include <sys/syslog.h>
52 #include <sys/sysent.h>
54 #include <vm/vm_zone.h>
55 static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE");
58 static struct ktr_header *ktrgetheader __P((int type));
59 static void ktrwrite __P((struct vnode *, struct ktr_header *, struct uio *));
60 static int ktrcanset __P((struct proc *,struct proc *));
61 static int ktrsetchildren __P((struct proc *,struct proc *,int,int,struct vnode *));
62 static int ktrops __P((struct proc *,struct proc *,int,int,struct vnode *));
65 static struct ktr_header *
69 struct ktr_header *kth;
70 struct proc *p = curproc; /* XXX */
72 MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header),
75 microtime(&kth->ktr_time);
76 kth->ktr_pid = p->p_pid;
77 bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN + 1);
82 ktrsyscall(vp, code, narg, args)
87 struct ktr_header *kth;
88 struct ktr_syscall *ktp;
89 int len = offsetof(struct ktr_syscall, ktr_args) +
90 (narg * sizeof(register_t));
91 struct proc *p = curproc; /* XXX */
95 p->p_traceflag |= KTRFAC_ACTIVE;
96 kth = ktrgetheader(KTR_SYSCALL);
97 MALLOC(ktp, struct ktr_syscall *, len, M_KTRACE, M_WAITOK);
100 argp = &ktp->ktr_args[0];
101 for (i = 0; i < narg; i++)
103 kth->ktr_buf = (caddr_t)ktp;
105 ktrwrite(vp, kth, NULL);
108 p->p_traceflag &= ~KTRFAC_ACTIVE;
112 ktrsysret(vp, code, error, retval)
117 struct ktr_header *kth;
118 struct ktr_sysret ktp;
119 struct proc *p = curproc; /* XXX */
121 p->p_traceflag |= KTRFAC_ACTIVE;
122 kth = ktrgetheader(KTR_SYSRET);
124 ktp.ktr_error = error;
125 ktp.ktr_retval = retval; /* what about val2 ? */
127 kth->ktr_buf = (caddr_t)&ktp;
128 kth->ktr_len = sizeof(struct ktr_sysret);
130 ktrwrite(vp, kth, NULL);
132 p->p_traceflag &= ~KTRFAC_ACTIVE;
140 struct ktr_header *kth;
141 struct proc *p = curproc; /* XXX */
144 * don't let vp get ripped out from under us
148 p->p_traceflag |= KTRFAC_ACTIVE;
149 kth = ktrgetheader(KTR_NAMEI);
150 kth->ktr_len = strlen(path);
153 ktrwrite(vp, kth, NULL);
157 p->p_traceflag &= ~KTRFAC_ACTIVE;
161 ktrgenio(vp, fd, rw, uio, error)
168 struct ktr_header *kth;
169 struct ktr_genio ktg;
170 struct proc *p = curproc; /* XXX */
175 * don't let p_tracep get ripped out from under us
179 p->p_traceflag |= KTRFAC_ACTIVE;
180 kth = ktrgetheader(KTR_GENIO);
183 kth->ktr_buf = (caddr_t)&ktg;
184 kth->ktr_len = sizeof(struct ktr_genio);
186 uio->uio_rw = UIO_WRITE;
188 ktrwrite(vp, kth, uio);
192 p->p_traceflag &= ~KTRFAC_ACTIVE;
196 ktrpsig(vp, sig, action, mask, code)
203 struct ktr_header *kth;
205 struct proc *p = curproc; /* XXX */
208 * don't let vp get ripped out from under us
212 p->p_traceflag |= KTRFAC_ACTIVE;
213 kth = ktrgetheader(KTR_PSIG);
214 kp.signo = (char)sig;
218 kth->ktr_buf = (caddr_t)&kp;
219 kth->ktr_len = sizeof (struct ktr_psig);
221 ktrwrite(vp, kth, NULL);
225 p->p_traceflag &= ~KTRFAC_ACTIVE;
229 ktrcsw(vp, out, user)
233 struct ktr_header *kth;
235 struct proc *p = curproc; /* XXX */
238 * don't let vp get ripped out from under us
242 p->p_traceflag |= KTRFAC_ACTIVE;
243 kth = ktrgetheader(KTR_CSW);
246 kth->ktr_buf = (caddr_t)&kc;
247 kth->ktr_len = sizeof (struct ktr_csw);
249 ktrwrite(vp, kth, NULL);
253 p->p_traceflag &= ~KTRFAC_ACTIVE;
257 /* Interface and common routines */
264 ktrace(struct ktrace_args *uap)
267 struct thread *td = curthread;
268 struct proc *curp = td->td_proc;
269 struct vnode *vp = NULL;
272 int facs = uap->facs & ~KTRFAC_ROOT;
273 int ops = KTROP(uap->ops);
274 int descend = uap->ops & KTRFLAG_DESCEND;
279 curp->p_traceflag |= KTRFAC_ACTIVE;
280 if (ops != KTROP_CLEAR) {
282 * an operation which requires a file argument.
284 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->fname, td);
285 error = vn_open(&nd, FREAD|FWRITE|O_NOFOLLOW, 0);
287 curp->p_traceflag &= ~KTRFAC_ACTIVE;
290 NDFREE(&nd, NDF_ONLY_PNBUF);
292 VOP_UNLOCK(vp, 0, td);
293 if (vp->v_type != VREG) {
294 (void) vn_close(vp, FREAD|FWRITE, td);
295 curp->p_traceflag &= ~KTRFAC_ACTIVE;
300 * Clear all uses of the tracefile. XXX umm, what happens to the
301 * loop if vn_close() blocks?
303 if (ops == KTROP_CLEARFILE) {
304 LIST_FOREACH(p, &allproc, p_list) {
305 if (p->p_tracep == vp) {
306 if (ktrcanset(curp, p) && p->p_tracep == vp) {
309 (void) vn_close(vp, FREAD|FWRITE, td);
318 * need something to (un)trace (XXX - why is this here?)
331 pg = pgfind(-uap->pid);
336 LIST_FOREACH(p, &pg->pg_members, p_pglist)
338 ret |= ktrsetchildren(curp, p, ops, facs, vp);
340 ret |= ktrops(curp, p, ops, facs, vp);
352 ret |= ktrsetchildren(curp, p, ops, facs, vp);
354 ret |= ktrops(curp, p, ops, facs, vp);
360 (void) vn_close(vp, FWRITE, td);
361 curp->p_traceflag &= ~KTRFAC_ACTIVE;
373 utrace(struct utrace_args *uap)
376 struct ktr_header *kth;
377 struct thread *td = curthread; /* XXX */
378 struct proc *p = td->td_proc;
382 if (!KTRPOINT(td, KTR_USER))
384 if (SCARG(uap, len) > KTR_USER_MAXLEN)
386 p->p_traceflag |= KTRFAC_ACTIVE;
388 * don't let p_tracep get ripped out from under us while we are
391 if ((vp = p->p_tracep) != NULL)
393 kth = ktrgetheader(KTR_USER);
394 MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK);
395 if (!copyin(uap->addr, cp, uap->len)) {
397 kth->ktr_len = uap->len;
398 ktrwrite(vp, kth, NULL);
404 p->p_traceflag &= ~KTRFAC_ACTIVE;
414 ktrops(curp, p, ops, facs, vp)
415 struct proc *p, *curp;
420 if (!ktrcanset(curp, p))
422 if (ops == KTROP_SET) {
423 if (p->p_tracep != vp) {
427 * if trace file already in use, relinquish
430 while ((vtmp = p->p_tracep) != NULL) {
436 p->p_traceflag |= facs;
437 if (curp->p_ucred->cr_uid == 0)
438 p->p_traceflag |= KTRFAC_ROOT;
441 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
444 /* no more tracing */
446 if ((vtmp = p->p_tracep) != NULL) {
457 ktrsetchildren(curp, top, ops, facs, vp)
458 struct proc *curp, *top;
467 ret |= ktrops(curp, p, ops, facs, vp);
469 * If this process has children, descend to them next,
470 * otherwise do any siblings, and if done with this level,
471 * follow back up the tree (but not past top).
473 if (!LIST_EMPTY(&p->p_children))
474 p = LIST_FIRST(&p->p_children);
478 if (LIST_NEXT(p, p_sibling)) {
479 p = LIST_NEXT(p, p_sibling);
489 ktrwrite(struct vnode *vp, struct ktr_header *kth, struct uio *uio)
492 struct iovec aiov[2];
493 struct thread *td = curthread;
494 struct proc *p = td->td_proc; /* XXX */
499 auio.uio_iov = &aiov[0];
501 auio.uio_segflg = UIO_SYSSPACE;
502 auio.uio_rw = UIO_WRITE;
503 aiov[0].iov_base = (caddr_t)kth;
504 aiov[0].iov_len = sizeof(struct ktr_header);
505 auio.uio_resid = sizeof(struct ktr_header);
507 auio.uio_td = curthread;
508 if (kth->ktr_len > 0) {
510 aiov[1].iov_base = kth->ktr_buf;
511 aiov[1].iov_len = kth->ktr_len;
512 auio.uio_resid += kth->ktr_len;
514 kth->ktr_len += uio->uio_resid;
516 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
517 (void)VOP_LEASE(vp, td, p->p_ucred, LEASE_WRITE);
518 error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, p->p_ucred);
519 if (error == 0 && uio != NULL) {
520 (void)VOP_LEASE(vp, td, p->p_ucred, LEASE_WRITE);
521 error = VOP_WRITE(vp, uio, IO_UNIT | IO_APPEND, p->p_ucred);
523 VOP_UNLOCK(vp, 0, td);
527 * If error encountered, give up tracing on this vnode. XXX what
528 * happens to the loop if vrele() blocks?
530 log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n",
532 LIST_FOREACH(p, &allproc, p_list) {
533 if (p->p_tracep == vp) {
542 * Return true if caller has permission to set the ktracing state
543 * of target. Essentially, the target can't possess any
544 * more permissions than the caller. KTRFAC_ROOT signifies that
545 * root previously set the tracing status on the target process, and
546 * so, only root may further change it.
548 * TODO: check groups. use caller effective gid.
551 ktrcanset(struct proc *callp, struct proc *targetp)
553 struct ucred *caller = callp->p_ucred;
554 struct ucred *target = targetp->p_ucred;
556 if (!PRISON_CHECK(caller, target))
558 if ((caller->cr_uid == target->cr_ruid &&
559 target->cr_ruid == target->cr_svuid &&
560 caller->cr_rgid == target->cr_rgid && /* XXX */
561 target->cr_rgid == target->cr_svgid &&
562 (targetp->p_traceflag & KTRFAC_ROOT) == 0 &&
563 (targetp->p_flag & P_SUGID) == 0) ||