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 1.30 2008/04/14 12:01:50 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 proc *, struct ktr_header *, struct uio *);
60 static int ktrcanset (struct proc *,struct proc *);
61 static int ktrsetchildren (struct proc *,struct proc *,int,int, ktrace_node_t);
62 static int ktrops (struct proc *,struct proc *,int,int, ktrace_node_t);
64 static struct ktr_header *
65 ktrgetheader(int type)
67 struct ktr_header *kth;
68 struct proc *p = curproc; /* XXX */
69 struct lwp *lp = curthread->td_lwp;
71 MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header),
74 /* XXX threaded flag is a hack at the moment */
75 kth->ktr_flags = (p->p_nthreads > 1) ? KTRH_THREADED : 0;
76 microtime(&kth->ktr_time);
77 kth->ktr_pid = p->p_pid;
78 kth->ktr_tid = lp->lwp_tid;
79 bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN + 1);
84 ktrsyscall(struct lwp *lp, int code, int narg, register_t args[])
86 struct ktr_header *kth;
87 struct ktr_syscall *ktp;
92 len = offsetof(struct ktr_syscall, ktr_args) +
93 (narg * sizeof(register_t));
96 * Setting the active bit prevents a ktrace recursion from the
99 lp->lwp_traceflag |= KTRFAC_ACTIVE;
100 kth = ktrgetheader(KTR_SYSCALL);
101 MALLOC(ktp, struct ktr_syscall *, len, M_KTRACE, M_WAITOK);
102 ktp->ktr_code = code;
103 ktp->ktr_narg = narg;
104 argp = &ktp->ktr_args[0];
105 for (i = 0; i < narg; i++)
107 kth->ktr_buf = (caddr_t)ktp;
109 ktrwrite(lp->lwp_proc, kth, NULL);
112 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
116 ktrsysret(struct lwp *lp, int code, int error, register_t retval)
118 struct ktr_header *kth;
119 struct ktr_sysret ktp;
121 lp->lwp_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(lp->lwp_proc, kth, NULL);
132 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
136 ktrnamei(struct lwp *lp, char *path)
138 struct ktr_header *kth;
140 lp->lwp_traceflag |= KTRFAC_ACTIVE;
141 kth = ktrgetheader(KTR_NAMEI);
142 kth->ktr_len = strlen(path);
145 ktrwrite(lp->lwp_proc, kth, NULL);
147 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
151 ktrgenio(struct lwp *lp, int fd, enum uio_rw rw, struct uio *uio, int error)
153 struct ktr_header *kth;
154 struct ktr_genio ktg;
158 lp->lwp_traceflag |= KTRFAC_ACTIVE;
159 kth = ktrgetheader(KTR_GENIO);
162 kth->ktr_buf = (caddr_t)&ktg;
163 kth->ktr_len = sizeof(struct ktr_genio);
165 uio->uio_rw = UIO_WRITE;
167 ktrwrite(lp->lwp_proc, kth, uio);
169 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
173 ktrpsig(struct lwp *lp, int sig, sig_t action, sigset_t *mask, int code)
175 struct ktr_header *kth;
178 lp->lwp_traceflag |= KTRFAC_ACTIVE;
179 kth = ktrgetheader(KTR_PSIG);
180 kp.signo = (char)sig;
184 kth->ktr_buf = (caddr_t)&kp;
185 kth->ktr_len = sizeof (struct ktr_psig);
187 ktrwrite(lp->lwp_proc, kth, NULL);
189 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
193 ktrcsw(struct lwp *lp, int out, int user)
195 struct ktr_header *kth;
198 lp->lwp_traceflag |= KTRFAC_ACTIVE;
199 kth = ktrgetheader(KTR_CSW);
202 kth->ktr_buf = (caddr_t)&kc;
203 kth->ktr_len = sizeof (struct ktr_csw);
205 ktrwrite(lp->lwp_proc, kth, NULL);
207 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
211 /* Interface and common routines */
217 struct ktrace_clear_info {
218 ktrace_node_t tracenode;
223 static int ktrace_clear_callback(struct proc *p, void *data);
228 sys_ktrace(struct ktrace_args *uap)
231 struct ktrace_clear_info info;
232 struct thread *td = curthread;
233 struct proc *curp = td->td_proc;
236 int facs = uap->facs & ~KTRFAC_ROOT;
237 int ops = KTROP(uap->ops);
238 int descend = uap->ops & KTRFLAG_DESCEND;
241 struct nlookupdata nd;
242 ktrace_node_t tracenode = NULL;
244 curp->p_traceflag |= KTRFAC_ACTIVE;
245 if (ops != KTROP_CLEAR) {
247 * an operation which requires a file argument.
249 error = nlookup_init(&nd, uap->fname,
250 UIO_USERSPACE, NLC_LOCKVP);
252 error = vn_open(&nd, NULL, FREAD|FWRITE|O_NOFOLLOW, 0);
253 if (error == 0 && nd.nl_open_vp->v_type != VREG)
256 curp->p_traceflag &= ~KTRFAC_ACTIVE;
260 MALLOC(tracenode, ktrace_node_t, sizeof (struct ktrace_node),
261 M_KTRACE, M_WAITOK | M_ZERO);
262 tracenode->kn_vp = nd.nl_open_vp;
263 tracenode->kn_refs = 1;
264 nd.nl_open_vp = NULL;
266 vn_unlock(tracenode->kn_vp);
269 * Clear all uses of the tracefile. Not the most efficient operation
272 if (ops == KTROP_CLEARFILE) {
273 info.tracenode = tracenode;
276 allproc_scan(ktrace_clear_callback, &info);
281 * need something to (un)trace (XXX - why is this here?)
294 pg = pgfind(-uap->pid);
299 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
301 ret |= ktrsetchildren(curp, p, ops, facs, tracenode);
303 ret |= ktrops(curp, p, ops, facs, tracenode);
315 ret |= ktrsetchildren(curp, p, ops, facs, tracenode);
317 ret |= ktrops(curp, p, ops, facs, tracenode);
323 ktrdestroy(&tracenode);
324 curp->p_traceflag &= ~KTRFAC_ACTIVE;
334 * NOTE: NOT MPSAFE (yet)
337 ktrace_clear_callback(struct proc *p, void *data)
339 struct ktrace_clear_info *info = data;
341 if (p->p_tracenode) {
342 if (info->rootclear) {
343 if (p->p_tracenode == info->tracenode) {
344 ktrdestroy(&p->p_tracenode);
348 if (p->p_tracenode->kn_vp == info->tracenode->kn_vp) {
349 if (ktrcanset(curproc, p)) {
350 ktrdestroy(&p->p_tracenode);
368 sys_utrace(struct utrace_args *uap)
371 struct ktr_header *kth;
372 struct thread *td = curthread; /* XXX */
373 struct proc *p = td->td_proc;
376 if (!KTRPOINT(td, KTR_USER))
378 if (uap->len > KTR_USER_MAXLEN)
380 td->td_lwp->lwp_traceflag |= KTRFAC_ACTIVE;
381 kth = ktrgetheader(KTR_USER);
382 MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK);
383 if (!copyin(uap->addr, cp, uap->len)) {
385 kth->ktr_len = uap->len;
386 ktrwrite(p, kth, NULL);
390 td->td_lwp->lwp_traceflag &= ~KTRFAC_ACTIVE;
399 ktrdestroy(struct ktrace_node **tracenodep)
401 ktrace_node_t tracenode;
403 if ((tracenode = *tracenodep) != NULL) {
405 KKASSERT(tracenode->kn_refs > 0);
406 /* XXX not MP safe yet */
407 --tracenode->kn_refs;
408 if (tracenode->kn_refs == 0) {
409 vn_close(tracenode->kn_vp, FREAD|FWRITE);
410 tracenode->kn_vp = NULL;
411 FREE(tracenode, M_KTRACE);
417 * This allows a process to inherit a ref on a tracenode and is also used
418 * as a temporary ref to prevent a tracenode from being destroyed out from
419 * under an active operation.
422 ktrinherit(ktrace_node_t tracenode)
425 KKASSERT(tracenode->kn_refs > 0);
426 ++tracenode->kn_refs;
433 ktrops(struct proc *curp, struct proc *p, int ops, int facs,
434 ktrace_node_t tracenode)
436 ktrace_node_t oldnode;
438 if (!ktrcanset(curp, p))
440 if (ops == KTROP_SET) {
441 if ((oldnode = p->p_tracenode) != tracenode) {
442 p->p_tracenode = ktrinherit(tracenode);
443 ktrdestroy(&oldnode);
445 p->p_traceflag |= facs;
446 if (curp->p_ucred->cr_uid == 0)
447 p->p_traceflag |= KTRFAC_ROOT;
450 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
451 /* no more tracing */
453 ktrdestroy(&p->p_tracenode);
461 ktrsetchildren(struct proc *curp, struct proc *top, int ops, int facs,
462 ktrace_node_t tracenode)
469 ret |= ktrops(curp, p, ops, facs, tracenode);
471 * If this process has children, descend to them next,
472 * otherwise do any siblings, and if done with this level,
473 * follow back up the tree (but not past top).
475 if (!LIST_EMPTY(&p->p_children))
476 p = LIST_FIRST(&p->p_children);
480 if (LIST_NEXT(p, p_sibling)) {
481 p = LIST_NEXT(p, p_sibling);
491 ktrwrite(struct proc *p, struct ktr_header *kth, struct uio *uio)
493 struct ktrace_clear_info info;
495 struct iovec aiov[2];
497 ktrace_node_t tracenode;
500 * We have to ref our tracenode to prevent it from being ripped out
501 * from under us while we are trying to use it. p_tracenode can
502 * go away at any time if another process gets a write error.
506 if (p->p_tracenode == NULL)
508 tracenode = ktrinherit(p->p_tracenode);
509 auio.uio_iov = &aiov[0];
511 auio.uio_segflg = UIO_SYSSPACE;
512 auio.uio_rw = UIO_WRITE;
513 aiov[0].iov_base = (caddr_t)kth;
514 aiov[0].iov_len = sizeof(struct ktr_header);
515 auio.uio_resid = sizeof(struct ktr_header);
517 auio.uio_td = curthread;
518 if (kth->ktr_len > 0) {
520 aiov[1].iov_base = kth->ktr_buf;
521 aiov[1].iov_len = kth->ktr_len;
522 auio.uio_resid += kth->ktr_len;
524 kth->ktr_len += uio->uio_resid;
526 vn_lock(tracenode->kn_vp, LK_EXCLUSIVE | LK_RETRY);
527 error = VOP_WRITE(tracenode->kn_vp, &auio,
528 IO_UNIT | IO_APPEND, p->p_ucred);
529 if (error == 0 && uio != NULL) {
530 error = VOP_WRITE(tracenode->kn_vp, uio,
531 IO_UNIT | IO_APPEND, p->p_ucred);
533 vn_unlock(tracenode->kn_vp);
536 * If an error occured, give up tracing on all processes
537 * using this tracenode. This is not MP safe but is
541 "ktrace write failed, errno %d, tracing stopped\n", error);
542 info.tracenode = tracenode;
545 allproc_scan(ktrace_clear_callback, &info);
547 ktrdestroy(&tracenode);
551 * Return true if caller has permission to set the ktracing state
552 * of target. Essentially, the target can't possess any
553 * more permissions than the caller. KTRFAC_ROOT signifies that
554 * root previously set the tracing status on the target process, and
555 * so, only root may further change it.
557 * TODO: check groups. use caller effective gid.
560 ktrcanset(struct proc *callp, struct proc *targetp)
562 struct ucred *caller = callp->p_ucred;
563 struct ucred *target = targetp->p_ucred;
565 if (!PRISON_CHECK(caller, target))
567 if ((caller->cr_uid == target->cr_ruid &&
568 target->cr_ruid == target->cr_svuid &&
569 caller->cr_rgid == target->cr_rgid && /* XXX */
570 target->cr_rgid == target->cr_svgid &&
571 (targetp->p_traceflag & KTRFAC_ROOT) == 0 &&
572 (targetp->p_flag & P_SUGID) == 0) ||