2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * @(#)kern_ktrace.c 8.2 (Berkeley) 9/23/93
30 * $FreeBSD: src/sys/kern/kern_ktrace.c,v 1.35.2.6 2002/07/05 22:36:38 darrenr Exp $
33 #include "opt_ktrace.h"
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/sysproto.h>
38 #include <sys/kernel.h>
40 #include <sys/fcntl.h>
42 #include <sys/nlookup.h>
43 #include <sys/vnode.h>
44 #include <sys/ktrace.h>
45 #include <sys/malloc.h>
46 #include <sys/syslog.h>
47 #include <sys/sysent.h>
49 #include <vm/vm_zone.h>
51 #include <sys/mplock2.h>
53 static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE");
56 static void ktrgetheader (struct ktr_header *kth, int type);
57 static struct ktr_syscall *ktrgetsyscall(struct ktr_header *kth,
58 struct ktr_syscall *ktp_cache, int narg);
59 static void ktrputsyscall(struct ktr_syscall *ktp_cache,
60 struct ktr_syscall *ktp);
61 static void ktrwrite (struct lwp *, struct ktr_header *, struct uio *);
62 static int ktrcanset (struct thread *,struct proc *);
63 static int ktrsetchildren (struct thread *, struct proc *,
64 int, int, ktrace_node_t);
65 static int ktrops (struct thread *,struct proc *,int,int, ktrace_node_t);
72 ktrgetheader(struct ktr_header *kth, int type)
74 thread_t td = curthread;
75 struct proc *p = td->td_proc;
76 struct lwp *lp = td->td_lwp;
79 /* XXX threaded flag is a hack at the moment */
80 kth->ktr_flags = (p->p_nthreads > 1) ? KTRH_THREADED : 0;
81 kth->ktr_flags |= KTRH_CPUID_ENCODE(td->td_gd->gd_cpuid);
82 /*microtime(&kth->ktr_time); set in ktrwrite */
83 kth->ktr_pid = p->p_pid;
84 kth->ktr_tid = lp->lwp_tid;
85 bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN + 1);
90 ktrgetsyscall(struct ktr_header *kth, struct ktr_syscall *ktp_cache, int narg)
94 len = offsetof(struct ktr_syscall, ktr_args[narg]);
95 if (len > sizeof(*ktp_cache))
96 ktp_cache = kmalloc(len, M_KTRACE, M_WAITOK);
97 kth->ktr_buf = (caddr_t)ktp_cache;
98 kth->ktr_len = (int)len;
104 ktrputsyscall(struct ktr_syscall *ktp_cache, struct ktr_syscall *ktp)
106 if (ktp != ktp_cache)
107 kfree(ktp, M_KTRACE);
111 ktrsyscall(struct lwp *lp, int code, int narg, register_t args[])
113 struct ktr_header kth;
114 struct ktr_syscall ktp_cache;
115 struct ktr_syscall *ktp;
120 * Setting the active bit prevents a ktrace recursion from the
121 * ktracing op itself.
123 lp->lwp_traceflag |= KTRFAC_ACTIVE;
124 ktrgetheader(&kth, KTR_SYSCALL);
126 ktp = ktrgetsyscall(&kth, &ktp_cache, narg);
127 ktp->ktr_code = code;
128 ktp->ktr_narg = narg;
129 argp = &ktp->ktr_args[0];
130 for (i = 0; i < narg; i++)
132 ktrwrite(lp, &kth, NULL);
134 ktrputsyscall(&ktp_cache, ktp);
135 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
139 ktrsysret(struct lwp *lp, int code, int error, register_t retval)
141 struct ktr_header kth;
142 struct ktr_sysret ktp;
144 lp->lwp_traceflag |= KTRFAC_ACTIVE;
145 ktrgetheader(&kth, KTR_SYSRET);
148 ktp.ktr_error = error;
150 ktp.ktr_retval = retval; /* what about val2 ? */
154 kth.ktr_buf = (caddr_t)&ktp;
155 kth.ktr_len = (int)sizeof(struct ktr_sysret);
157 ktrwrite(lp, &kth, NULL);
158 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
162 ktrnamei(struct lwp *lp, char *path)
164 struct ktr_header kth;
166 lp->lwp_traceflag |= KTRFAC_ACTIVE;
167 ktrgetheader(&kth, KTR_NAMEI);
169 kth.ktr_len = (int)strlen(path);
172 ktrwrite(lp, &kth, NULL);
173 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
177 ktrgenio(struct lwp *lp, int fd, enum uio_rw rw, struct uio *uio, int error)
179 struct ktr_header kth;
180 struct ktr_genio ktg;
184 lp->lwp_traceflag |= KTRFAC_ACTIVE;
185 ktrgetheader(&kth, KTR_GENIO);
189 kth.ktr_buf = (caddr_t)&ktg;
190 kth.ktr_len = (int)sizeof(struct ktr_genio);
192 uio->uio_rw = UIO_WRITE;
194 ktrwrite(lp, &kth, uio);
195 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
199 ktrpsig(struct lwp *lp, int sig, sig_t action, sigset_t *mask, int code)
201 struct ktr_header kth;
204 lp->lwp_traceflag |= KTRFAC_ACTIVE;
205 ktrgetheader(&kth, KTR_PSIG);
207 kp.signo = (char)sig;
211 kth.ktr_buf = (caddr_t)&kp;
212 kth.ktr_len = (int)sizeof(struct ktr_psig);
214 ktrwrite(lp, &kth, NULL);
215 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
219 ktrcsw(struct lwp *lp, int out, int user)
221 struct ktr_header kth;
224 lp->lwp_traceflag |= KTRFAC_ACTIVE;
225 ktrgetheader(&kth, KTR_CSW);
229 kth.ktr_buf = (caddr_t)&kc;
230 kth.ktr_len = (int)sizeof(struct ktr_csw);
232 ktrwrite(lp, &kth, NULL);
233 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
237 /* Interface and common routines */
243 struct ktrace_clear_info {
244 ktrace_node_t tracenode;
249 static int ktrace_clear_callback(struct proc *p, void *data);
257 sys_ktrace(struct ktrace_args *uap)
260 struct ktrace_clear_info info;
261 struct thread *td = curthread;
262 struct proc *curp = td->td_proc;
265 int facs = uap->facs & ~KTRFAC_ROOT;
266 int ops = KTROP(uap->ops);
267 int descend = uap->ops & KTRFLAG_DESCEND;
270 struct nlookupdata nd;
271 ktrace_node_t tracenode = NULL;
274 curp->p_traceflag |= KTRFAC_ACTIVE;
275 if (ops != KTROP_CLEAR) {
277 * an operation which requires a file argument.
279 error = nlookup_init(&nd, uap->fname,
280 UIO_USERSPACE, NLC_LOCKVP);
282 error = vn_open(&nd, NULL, FREAD|FWRITE|O_NOFOLLOW, 0);
283 if (error == 0 && nd.nl_open_vp->v_type != VREG)
286 curp->p_traceflag &= ~KTRFAC_ACTIVE;
290 tracenode = kmalloc(sizeof(struct ktrace_node), M_KTRACE,
292 tracenode->kn_vp = nd.nl_open_vp;
293 tracenode->kn_refs = 1;
294 nd.nl_open_vp = NULL;
296 vn_unlock(tracenode->kn_vp);
299 * Clear all uses of the tracefile. Not the most efficient operation
302 if (ops == KTROP_CLEARFILE) {
303 info.tracenode = tracenode;
306 allproc_scan(ktrace_clear_callback, &info);
311 * need something to (un)trace (XXX - why is this here?)
322 * By process group. Process group is referenced, preventing
325 pg = pgfind(-uap->pid);
330 lwkt_gettoken(&pg->pg_token);
331 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
334 ret |= ktrsetchildren(td, p, ops, facs, tracenode);
336 ret |= ktrops(td, p, ops, facs, tracenode);
339 lwkt_reltoken(&pg->pg_token);
351 ret |= ktrsetchildren(td, p, ops, facs, tracenode);
353 ret |= ktrops(td, p, ops, facs, tracenode);
360 ktrdestroy(&tracenode);
361 curp->p_traceflag &= ~KTRFAC_ACTIVE;
372 * NOTE: NOT MPSAFE (yet)
375 ktrace_clear_callback(struct proc *p, void *data)
377 struct ktrace_clear_info *info = data;
379 if (p->p_tracenode) {
380 if (info->rootclear) {
381 if (p->p_tracenode == info->tracenode) {
382 ktrdestroy(&p->p_tracenode);
386 if (p->p_tracenode->kn_vp == info->tracenode->kn_vp) {
387 if (ktrcanset(curthread, p)) {
388 ktrdestroy(&p->p_tracenode);
407 sys_utrace(struct utrace_args *uap)
410 struct ktr_header kth;
411 struct thread *td = curthread; /* XXX */
415 if (!KTRPOINT(td, KTR_USER))
417 if (uap->len > KTR_USER_MAXLEN)
419 td->td_lwp->lwp_traceflag |= KTRFAC_ACTIVE;
420 ktrgetheader(&kth, KTR_USER);
421 if (uap->len <= sizeof(cp_cache))
424 cp = kmalloc(uap->len, M_KTRACE, M_WAITOK);
426 if (!copyin(uap->addr, cp, uap->len)) {
428 kth.ktr_len = uap->len;
429 ktrwrite(td->td_lwp, &kth, NULL);
433 td->td_lwp->lwp_traceflag &= ~KTRFAC_ACTIVE;
442 ktrdestroy(struct ktrace_node **tracenodep)
444 ktrace_node_t tracenode;
446 if ((tracenode = *tracenodep) != NULL) {
448 KKASSERT(tracenode->kn_refs > 0);
449 if (atomic_fetchadd_int(&tracenode->kn_refs, -1) == 1) {
450 vn_close(tracenode->kn_vp, FREAD|FWRITE, NULL);
451 tracenode->kn_vp = NULL;
452 kfree(tracenode, M_KTRACE);
458 * This allows a process to inherit a ref on a tracenode and is also used
459 * as a temporary ref to prevent a tracenode from being destroyed out from
460 * under an active operation.
463 ktrinherit(ktrace_node_t tracenode)
466 KKASSERT(tracenode->kn_refs > 0);
467 atomic_add_int(&tracenode->kn_refs, 1);
474 ktrops(struct thread *td, struct proc *p, int ops, int facs,
475 ktrace_node_t tracenode)
477 ktrace_node_t oldnode;
479 if (!ktrcanset(td, p))
481 if (ops == KTROP_SET) {
482 if ((oldnode = p->p_tracenode) != tracenode) {
483 p->p_tracenode = ktrinherit(tracenode);
484 ktrdestroy(&oldnode);
486 p->p_traceflag |= facs;
487 if (td->td_ucred->cr_uid == 0)
488 p->p_traceflag |= KTRFAC_ROOT;
491 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
492 /* no more tracing */
494 ktrdestroy(&p->p_tracenode);
502 ktrsetchildren(struct thread *td, struct proc *top, int ops, int facs,
503 ktrace_node_t tracenode)
511 lwkt_gettoken(&p->p_token);
514 ret |= ktrops(td, p, ops, facs, tracenode);
517 * If this process has children, descend to them next,
518 * otherwise do any siblings, and if done with this level,
519 * follow back up the tree (but not past top).
521 if ((np = LIST_FIRST(&p->p_children)) != NULL) {
527 if ((np = LIST_NEXT(p, p_sibling)) != NULL) {
533 * recurse up to parent, set p in our inner
534 * loop when doing this. np can be NULL if
535 * we race a reparenting to init (thus 'top'
536 * is skipped past and never encountered).
542 lwkt_reltoken(&p->p_token);
545 lwkt_gettoken(&p->p_token);
548 lwkt_reltoken(&p->p_token);
553 /* Already held, but we need the token too */
554 lwkt_gettoken(&p->p_token);
560 ktrwrite(struct lwp *lp, struct ktr_header *kth, struct uio *uio)
562 struct ktrace_clear_info info;
564 struct iovec aiov[2];
566 ktrace_node_t tracenode;
569 * We have to ref our tracenode to prevent it from being ripped out
570 * from under us while we are trying to use it. p_tracenode can
571 * go away at any time if another process gets a write error.
575 if (lp->lwp_proc->p_tracenode == NULL)
577 tracenode = ktrinherit(lp->lwp_proc->p_tracenode);
578 auio.uio_iov = &aiov[0];
580 auio.uio_segflg = UIO_SYSSPACE;
581 auio.uio_rw = UIO_WRITE;
582 aiov[0].iov_base = (caddr_t)kth;
583 aiov[0].iov_len = sizeof(struct ktr_header);
584 auio.uio_resid = sizeof(struct ktr_header);
586 auio.uio_td = curthread;
587 if (kth->ktr_len > 0) {
589 aiov[1].iov_base = kth->ktr_buf;
590 aiov[1].iov_len = kth->ktr_len;
591 auio.uio_resid += kth->ktr_len;
593 kth->ktr_len += uio->uio_resid;
597 * NOTE: Must set timestamp after obtaining lock to ensure no
598 * timestamp reversals in the output file.
600 vn_lock(tracenode->kn_vp, LK_EXCLUSIVE | LK_RETRY);
601 microtime(&kth->ktr_time);
602 error = VOP_WRITE(tracenode->kn_vp, &auio,
603 IO_UNIT | IO_APPEND, lp->lwp_thread->td_ucred);
604 if (error == 0 && uio != NULL) {
605 error = VOP_WRITE(tracenode->kn_vp, uio,
606 IO_UNIT | IO_APPEND, lp->lwp_thread->td_ucred);
608 vn_unlock(tracenode->kn_vp);
611 * If an error occured, give up tracing on all processes
612 * using this tracenode. This is not MP safe but is
616 "ktrace write failed, errno %d, tracing stopped\n", error);
617 info.tracenode = tracenode;
620 allproc_scan(ktrace_clear_callback, &info);
622 ktrdestroy(&tracenode);
626 * Return true if caller has permission to set the ktracing state
627 * of target. Essentially, the target can't possess any
628 * more permissions than the caller. KTRFAC_ROOT signifies that
629 * root previously set the tracing status on the target process, and
630 * so, only root may further change it.
632 * TODO: check groups. use caller effective gid.
635 ktrcanset(struct thread *calltd, struct proc *targetp)
637 struct ucred *caller = calltd->td_ucred;
638 struct ucred *target = targetp->p_ucred;
640 if (!PRISON_CHECK(caller, target))
642 if ((caller->cr_uid == target->cr_ruid &&
643 target->cr_ruid == target->cr_svuid &&
644 caller->cr_rgid == target->cr_rgid && /* XXX */
645 target->cr_rgid == target->cr_svgid &&
646 (targetp->p_traceflag & KTRFAC_ROOT) == 0 &&
647 (targetp->p_flags & P_SUGID) == 0) ||