2 * Copyright (c) 1989, 1993
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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 1.19 2005/07/28 18:10:23 dillon 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/nlookup.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 (int type);
59 static void ktrwrite (struct vnode *, struct ktr_header *, struct uio *);
60 static int ktrcanset (struct proc *,struct proc *);
61 static int ktrsetchildren (struct proc *,struct proc *,int,int,struct vnode *);
62 static int ktrops (struct proc *,struct proc *,int,int,struct vnode *);
65 static struct ktr_header *
66 ktrgetheader(int type)
68 struct ktr_header *kth;
69 struct proc *p = curproc; /* XXX */
71 MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header),
74 microtime(&kth->ktr_time);
75 kth->ktr_pid = p->p_pid;
76 bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN + 1);
81 ktrsyscall(struct vnode *vp, int code, int narg, register_t args[])
83 struct ktr_header *kth;
84 struct ktr_syscall *ktp;
85 int len = offsetof(struct ktr_syscall, ktr_args) +
86 (narg * sizeof(register_t));
87 struct proc *p = curproc; /* XXX */
91 p->p_traceflag |= KTRFAC_ACTIVE;
92 kth = ktrgetheader(KTR_SYSCALL);
93 MALLOC(ktp, struct ktr_syscall *, len, M_KTRACE, M_WAITOK);
96 argp = &ktp->ktr_args[0];
97 for (i = 0; i < narg; i++)
99 kth->ktr_buf = (caddr_t)ktp;
101 ktrwrite(vp, kth, NULL);
104 p->p_traceflag &= ~KTRFAC_ACTIVE;
108 ktrsysret(struct vnode *vp, int code, int error, register_t retval)
110 struct ktr_header *kth;
111 struct ktr_sysret ktp;
112 struct proc *p = curproc; /* XXX */
114 p->p_traceflag |= KTRFAC_ACTIVE;
115 kth = ktrgetheader(KTR_SYSRET);
117 ktp.ktr_error = error;
118 ktp.ktr_retval = retval; /* what about val2 ? */
120 kth->ktr_buf = (caddr_t)&ktp;
121 kth->ktr_len = sizeof(struct ktr_sysret);
123 ktrwrite(vp, kth, NULL);
125 p->p_traceflag &= ~KTRFAC_ACTIVE;
129 ktrnamei(struct vnode *vp, char *path)
131 struct ktr_header *kth;
132 struct proc *p = curproc; /* XXX */
135 * don't let vp get ripped out from under us
139 p->p_traceflag |= KTRFAC_ACTIVE;
140 kth = ktrgetheader(KTR_NAMEI);
141 kth->ktr_len = strlen(path);
144 ktrwrite(vp, kth, NULL);
148 p->p_traceflag &= ~KTRFAC_ACTIVE;
152 ktrgenio(struct vnode *vp, int fd, enum uio_rw rw, struct uio *uio, int error)
154 struct ktr_header *kth;
155 struct ktr_genio ktg;
156 struct proc *p = curproc; /* XXX */
161 * don't let p_tracep get ripped out from under us
165 p->p_traceflag |= KTRFAC_ACTIVE;
166 kth = ktrgetheader(KTR_GENIO);
169 kth->ktr_buf = (caddr_t)&ktg;
170 kth->ktr_len = sizeof(struct ktr_genio);
172 uio->uio_rw = UIO_WRITE;
174 ktrwrite(vp, kth, uio);
178 p->p_traceflag &= ~KTRFAC_ACTIVE;
182 ktrpsig(struct vnode *vp, int sig, sig_t action, sigset_t *mask, int code)
184 struct ktr_header *kth;
186 struct proc *p = curproc; /* XXX */
189 * don't let vp get ripped out from under us
193 p->p_traceflag |= KTRFAC_ACTIVE;
194 kth = ktrgetheader(KTR_PSIG);
195 kp.signo = (char)sig;
199 kth->ktr_buf = (caddr_t)&kp;
200 kth->ktr_len = sizeof (struct ktr_psig);
202 ktrwrite(vp, kth, NULL);
206 p->p_traceflag &= ~KTRFAC_ACTIVE;
210 ktrcsw(struct vnode *vp, int out, int user)
212 struct ktr_header *kth;
214 struct proc *p = curproc; /* XXX */
217 * don't let vp get ripped out from under us
221 p->p_traceflag |= KTRFAC_ACTIVE;
222 kth = ktrgetheader(KTR_CSW);
225 kth->ktr_buf = (caddr_t)&kc;
226 kth->ktr_len = sizeof (struct ktr_csw);
228 ktrwrite(vp, kth, NULL);
232 p->p_traceflag &= ~KTRFAC_ACTIVE;
236 /* Interface and common routines */
243 ktrace(struct ktrace_args *uap)
246 struct thread *td = curthread;
247 struct proc *curp = td->td_proc;
248 struct vnode *vp = NULL;
251 int facs = uap->facs & ~KTRFAC_ROOT;
252 int ops = KTROP(uap->ops);
253 int descend = uap->ops & KTRFLAG_DESCEND;
256 struct nlookupdata nd;
258 curp->p_traceflag |= KTRFAC_ACTIVE;
259 if (ops != KTROP_CLEAR) {
261 * an operation which requires a file argument.
263 error = nlookup_init(&nd, uap->fname,
264 UIO_USERSPACE, NLC_LOCKVP);
266 error = vn_open(&nd, NULL, FREAD|FWRITE|O_NOFOLLOW, 0);
267 if (error == 0 && nd.nl_open_vp->v_type != VREG)
270 curp->p_traceflag &= ~KTRFAC_ACTIVE;
275 nd.nl_open_vp = NULL;
277 VOP_UNLOCK(vp, 0, td);
280 * Clear all uses of the tracefile. XXX umm, what happens to the
281 * loop if vn_close() blocks?
283 if (ops == KTROP_CLEARFILE) {
284 FOREACH_PROC_IN_SYSTEM(p) {
285 if (p->p_tracep == vp) {
286 if (ktrcanset(curp, p) && p->p_tracep == vp) {
289 vn_close(vp, FREAD|FWRITE, td);
298 * need something to (un)trace (XXX - why is this here?)
311 pg = pgfind(-uap->pid);
316 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
318 ret |= ktrsetchildren(curp, p, ops, facs, vp);
320 ret |= ktrops(curp, p, ops, facs, vp);
332 ret |= ktrsetchildren(curp, p, ops, facs, vp);
334 ret |= ktrops(curp, p, ops, facs, vp);
340 vn_close(vp, FWRITE, td);
341 curp->p_traceflag &= ~KTRFAC_ACTIVE;
353 utrace(struct utrace_args *uap)
356 struct ktr_header *kth;
357 struct thread *td = curthread; /* XXX */
358 struct proc *p = td->td_proc;
362 if (!KTRPOINT(td, KTR_USER))
364 if (uap->len > KTR_USER_MAXLEN)
366 p->p_traceflag |= KTRFAC_ACTIVE;
368 * don't let p_tracep get ripped out from under us while we are
371 if ((vp = p->p_tracep) != NULL)
373 kth = ktrgetheader(KTR_USER);
374 MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK);
375 if (!copyin(uap->addr, cp, uap->len)) {
377 kth->ktr_len = uap->len;
378 ktrwrite(vp, kth, NULL);
384 p->p_traceflag &= ~KTRFAC_ACTIVE;
394 ktrops(struct proc *curp, struct proc *p, int ops, int facs, struct vnode *vp)
397 if (!ktrcanset(curp, p))
399 if (ops == KTROP_SET) {
400 if (p->p_tracep != vp) {
404 * if trace file already in use, relinquish
407 while ((vtmp = p->p_tracep) != NULL) {
413 p->p_traceflag |= facs;
414 if (curp->p_ucred->cr_uid == 0)
415 p->p_traceflag |= KTRFAC_ROOT;
418 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
421 /* no more tracing */
423 if ((vtmp = p->p_tracep) != NULL) {
434 ktrsetchildren(struct proc *curp, struct proc *top, int ops, int facs,
442 ret |= ktrops(curp, p, ops, facs, vp);
444 * If this process has children, descend to them next,
445 * otherwise do any siblings, and if done with this level,
446 * follow back up the tree (but not past top).
448 if (!LIST_EMPTY(&p->p_children))
449 p = LIST_FIRST(&p->p_children);
453 if (LIST_NEXT(p, p_sibling)) {
454 p = LIST_NEXT(p, p_sibling);
464 ktrwrite(struct vnode *vp, struct ktr_header *kth, struct uio *uio)
467 struct iovec aiov[2];
468 struct thread *td = curthread;
469 struct proc *p = td->td_proc; /* XXX */
473 * Since multiple processes may be trying to ktrace, we must vref
474 * the vnode to prevent it from being ripped out from under us in
475 * case another process gets a write error while ktracing and removes
476 * the reference from the proc.
481 auio.uio_iov = &aiov[0];
483 auio.uio_segflg = UIO_SYSSPACE;
484 auio.uio_rw = UIO_WRITE;
485 aiov[0].iov_base = (caddr_t)kth;
486 aiov[0].iov_len = sizeof(struct ktr_header);
487 auio.uio_resid = sizeof(struct ktr_header);
489 auio.uio_td = curthread;
490 if (kth->ktr_len > 0) {
492 aiov[1].iov_base = kth->ktr_buf;
493 aiov[1].iov_len = kth->ktr_len;
494 auio.uio_resid += kth->ktr_len;
496 kth->ktr_len += uio->uio_resid;
498 VOP_LEASE(vp, td, p->p_ucred, LEASE_WRITE);
499 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
500 error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, p->p_ucred);
501 if (error == 0 && uio != NULL) {
502 VOP_LEASE(vp, td, p->p_ucred, LEASE_WRITE);
503 error = VOP_WRITE(vp, uio, IO_UNIT | IO_APPEND, p->p_ucred);
505 VOP_UNLOCK(vp, 0, td);
510 * If error encountered, give up tracing on this vnode. XXX what
511 * happens to the loop if vrele() blocks?
513 log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n",
515 FOREACH_PROC_IN_SYSTEM(p) {
516 if (p->p_tracep == vp) {
525 * Return true if caller has permission to set the ktracing state
526 * of target. Essentially, the target can't possess any
527 * more permissions than the caller. KTRFAC_ROOT signifies that
528 * root previously set the tracing status on the target process, and
529 * so, only root may further change it.
531 * TODO: check groups. use caller effective gid.
534 ktrcanset(struct proc *callp, struct proc *targetp)
536 struct ucred *caller = callp->p_ucred;
537 struct ucred *target = targetp->p_ucred;
539 if (!PRISON_CHECK(caller, target))
541 if ((caller->cr_uid == target->cr_ruid &&
542 target->cr_ruid == target->cr_svuid &&
543 caller->cr_rgid == target->cr_rgid && /* XXX */
544 target->cr_rgid == target->cr_svgid &&
545 (targetp->p_traceflag & KTRFAC_ROOT) == 0 &&
546 (targetp->p_flag & P_SUGID) == 0) ||