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>
56 #include <sys/mplock2.h>
58 static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE");
61 static struct ktr_header *ktrgetheader (int type);
62 static void ktrwrite (struct lwp *, struct ktr_header *, struct uio *);
63 static int ktrcanset (struct thread *,struct proc *);
64 static int ktrsetchildren (struct thread *,struct proc *,int,int, ktrace_node_t);
65 static int ktrops (struct thread *,struct proc *,int,int, ktrace_node_t);
70 static struct ktr_header *
71 ktrgetheader(int type)
73 struct ktr_header *kth;
74 struct proc *p = curproc; /* XXX */
75 struct lwp *lp = curthread->td_lwp;
77 MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header),
80 /* XXX threaded flag is a hack at the moment */
81 kth->ktr_flags = (p->p_nthreads > 1) ? KTRH_THREADED : 0;
82 microtime(&kth->ktr_time);
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 ktrsyscall(struct lwp *lp, int code, int narg, register_t args[])
92 struct ktr_header *kth;
93 struct ktr_syscall *ktp;
98 len = offsetof(struct ktr_syscall, ktr_args) +
99 (narg * sizeof(register_t));
102 * Setting the active bit prevents a ktrace recursion from the
103 * ktracing op itself.
105 lp->lwp_traceflag |= KTRFAC_ACTIVE;
106 kth = ktrgetheader(KTR_SYSCALL);
107 MALLOC(ktp, struct ktr_syscall *, len, M_KTRACE, M_WAITOK);
108 ktp->ktr_code = code;
109 ktp->ktr_narg = narg;
110 argp = &ktp->ktr_args[0];
111 for (i = 0; i < narg; i++)
113 kth->ktr_buf = (caddr_t)ktp;
115 ktrwrite(lp, kth, NULL);
118 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
122 ktrsysret(struct lwp *lp, int code, int error, register_t retval)
124 struct ktr_header *kth;
125 struct ktr_sysret ktp;
127 lp->lwp_traceflag |= KTRFAC_ACTIVE;
128 kth = ktrgetheader(KTR_SYSRET);
130 ktp.ktr_error = error;
131 ktp.ktr_retval = retval; /* what about val2 ? */
133 kth->ktr_buf = (caddr_t)&ktp;
134 kth->ktr_len = sizeof(struct ktr_sysret);
136 ktrwrite(lp, kth, NULL);
138 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
142 ktrnamei(struct lwp *lp, char *path)
144 struct ktr_header *kth;
146 lp->lwp_traceflag |= KTRFAC_ACTIVE;
147 kth = ktrgetheader(KTR_NAMEI);
148 kth->ktr_len = strlen(path);
151 ktrwrite(lp, kth, NULL);
153 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
157 ktrgenio(struct lwp *lp, int fd, enum uio_rw rw, struct uio *uio, int error)
159 struct ktr_header *kth;
160 struct ktr_genio ktg;
164 lp->lwp_traceflag |= KTRFAC_ACTIVE;
165 kth = ktrgetheader(KTR_GENIO);
168 kth->ktr_buf = (caddr_t)&ktg;
169 kth->ktr_len = sizeof(struct ktr_genio);
171 uio->uio_rw = UIO_WRITE;
173 ktrwrite(lp, kth, uio);
175 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
179 ktrpsig(struct lwp *lp, int sig, sig_t action, sigset_t *mask, int code)
181 struct ktr_header *kth;
184 lp->lwp_traceflag |= KTRFAC_ACTIVE;
185 kth = ktrgetheader(KTR_PSIG);
186 kp.signo = (char)sig;
190 kth->ktr_buf = (caddr_t)&kp;
191 kth->ktr_len = sizeof (struct ktr_psig);
193 ktrwrite(lp, kth, NULL);
195 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
199 ktrcsw(struct lwp *lp, int out, int user)
201 struct ktr_header *kth;
204 lp->lwp_traceflag |= KTRFAC_ACTIVE;
205 kth = ktrgetheader(KTR_CSW);
208 kth->ktr_buf = (caddr_t)&kc;
209 kth->ktr_len = sizeof (struct ktr_csw);
211 ktrwrite(lp, kth, NULL);
213 lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
217 /* Interface and common routines */
223 struct ktrace_clear_info {
224 ktrace_node_t tracenode;
229 static int ktrace_clear_callback(struct proc *p, void *data);
237 sys_ktrace(struct ktrace_args *uap)
240 struct ktrace_clear_info info;
241 struct thread *td = curthread;
242 struct proc *curp = td->td_proc;
245 int facs = uap->facs & ~KTRFAC_ROOT;
246 int ops = KTROP(uap->ops);
247 int descend = uap->ops & KTRFLAG_DESCEND;
250 struct nlookupdata nd;
251 ktrace_node_t tracenode = NULL;
254 curp->p_traceflag |= KTRFAC_ACTIVE;
255 if (ops != KTROP_CLEAR) {
257 * an operation which requires a file argument.
259 error = nlookup_init(&nd, uap->fname,
260 UIO_USERSPACE, NLC_LOCKVP);
262 error = vn_open(&nd, NULL, FREAD|FWRITE|O_NOFOLLOW, 0);
263 if (error == 0 && nd.nl_open_vp->v_type != VREG)
266 curp->p_traceflag &= ~KTRFAC_ACTIVE;
270 MALLOC(tracenode, ktrace_node_t, sizeof (struct ktrace_node),
271 M_KTRACE, M_WAITOK | M_ZERO);
272 tracenode->kn_vp = nd.nl_open_vp;
273 tracenode->kn_refs = 1;
274 nd.nl_open_vp = NULL;
276 vn_unlock(tracenode->kn_vp);
279 * Clear all uses of the tracefile. Not the most efficient operation
282 if (ops == KTROP_CLEARFILE) {
283 info.tracenode = tracenode;
286 allproc_scan(ktrace_clear_callback, &info);
291 * need something to (un)trace (XXX - why is this here?)
302 * By process group. Process group is referenced, preventing
305 pg = pgfind(-uap->pid);
310 lwkt_gettoken(&pg->pg_token);
311 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
314 ret |= ktrsetchildren(td, p, ops, facs, tracenode);
316 ret |= ktrops(td, p, ops, facs, tracenode);
319 lwkt_reltoken(&pg->pg_token);
331 ret |= ktrsetchildren(td, p, ops, facs, tracenode);
333 ret |= ktrops(td, p, ops, facs, tracenode);
340 ktrdestroy(&tracenode);
341 curp->p_traceflag &= ~KTRFAC_ACTIVE;
352 * NOTE: NOT MPSAFE (yet)
355 ktrace_clear_callback(struct proc *p, void *data)
357 struct ktrace_clear_info *info = data;
359 if (p->p_tracenode) {
360 if (info->rootclear) {
361 if (p->p_tracenode == info->tracenode) {
362 ktrdestroy(&p->p_tracenode);
366 if (p->p_tracenode->kn_vp == info->tracenode->kn_vp) {
367 if (ktrcanset(curthread, p)) {
368 ktrdestroy(&p->p_tracenode);
387 sys_utrace(struct utrace_args *uap)
390 struct ktr_header *kth;
391 struct thread *td = curthread; /* XXX */
394 if (!KTRPOINT(td, KTR_USER))
396 if (uap->len > KTR_USER_MAXLEN)
398 td->td_lwp->lwp_traceflag |= KTRFAC_ACTIVE;
399 kth = ktrgetheader(KTR_USER);
400 MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK);
401 if (!copyin(uap->addr, cp, uap->len)) {
403 kth->ktr_len = uap->len;
404 ktrwrite(td->td_lwp, kth, NULL);
408 td->td_lwp->lwp_traceflag &= ~KTRFAC_ACTIVE;
417 ktrdestroy(struct ktrace_node **tracenodep)
419 ktrace_node_t tracenode;
421 if ((tracenode = *tracenodep) != NULL) {
423 KKASSERT(tracenode->kn_refs > 0);
424 if (atomic_fetchadd_int(&tracenode->kn_refs, -1) == 1) {
425 vn_close(tracenode->kn_vp, FREAD|FWRITE);
426 tracenode->kn_vp = NULL;
427 FREE(tracenode, M_KTRACE);
433 * This allows a process to inherit a ref on a tracenode and is also used
434 * as a temporary ref to prevent a tracenode from being destroyed out from
435 * under an active operation.
438 ktrinherit(ktrace_node_t tracenode)
441 KKASSERT(tracenode->kn_refs > 0);
442 atomic_add_int(&tracenode->kn_refs, 1);
449 ktrops(struct thread *td, struct proc *p, int ops, int facs,
450 ktrace_node_t tracenode)
452 ktrace_node_t oldnode;
454 if (!ktrcanset(td, p))
456 if (ops == KTROP_SET) {
457 if ((oldnode = p->p_tracenode) != tracenode) {
458 p->p_tracenode = ktrinherit(tracenode);
459 ktrdestroy(&oldnode);
461 p->p_traceflag |= facs;
462 if (td->td_ucred->cr_uid == 0)
463 p->p_traceflag |= KTRFAC_ROOT;
466 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
467 /* no more tracing */
469 ktrdestroy(&p->p_tracenode);
477 ktrsetchildren(struct thread *td, struct proc *top, int ops, int facs,
478 ktrace_node_t tracenode)
489 while ((p = np) != NULL) {
490 lwkt_gettoken(&p->p_token);
491 ret |= ktrops(td, p, ops, facs, tracenode);
494 * If this process has children, descend to them next,
495 * otherwise do any siblings, and if done with this level,
496 * follow back up the tree (but not past top).
498 if (!LIST_EMPTY(&p->p_children)) {
499 np = LIST_FIRST(&p->p_children);
506 if (LIST_NEXT(p, p_sibling)) {
507 np = LIST_NEXT(p, p_sibling);
515 lwkt_reltoken(&p->p_token);
522 ktrwrite(struct lwp *lp, struct ktr_header *kth, struct uio *uio)
524 struct ktrace_clear_info info;
526 struct iovec aiov[2];
528 ktrace_node_t tracenode;
531 * We have to ref our tracenode to prevent it from being ripped out
532 * from under us while we are trying to use it. p_tracenode can
533 * go away at any time if another process gets a write error.
537 if (lp->lwp_proc->p_tracenode == NULL)
539 tracenode = ktrinherit(lp->lwp_proc->p_tracenode);
540 auio.uio_iov = &aiov[0];
542 auio.uio_segflg = UIO_SYSSPACE;
543 auio.uio_rw = UIO_WRITE;
544 aiov[0].iov_base = (caddr_t)kth;
545 aiov[0].iov_len = sizeof(struct ktr_header);
546 auio.uio_resid = sizeof(struct ktr_header);
548 auio.uio_td = curthread;
549 if (kth->ktr_len > 0) {
551 aiov[1].iov_base = kth->ktr_buf;
552 aiov[1].iov_len = kth->ktr_len;
553 auio.uio_resid += kth->ktr_len;
555 kth->ktr_len += uio->uio_resid;
557 vn_lock(tracenode->kn_vp, LK_EXCLUSIVE | LK_RETRY);
558 error = VOP_WRITE(tracenode->kn_vp, &auio,
559 IO_UNIT | IO_APPEND, lp->lwp_thread->td_ucred);
560 if (error == 0 && uio != NULL) {
561 error = VOP_WRITE(tracenode->kn_vp, uio,
562 IO_UNIT | IO_APPEND, lp->lwp_thread->td_ucred);
564 vn_unlock(tracenode->kn_vp);
567 * If an error occured, give up tracing on all processes
568 * using this tracenode. This is not MP safe but is
572 "ktrace write failed, errno %d, tracing stopped\n", error);
573 info.tracenode = tracenode;
576 allproc_scan(ktrace_clear_callback, &info);
578 ktrdestroy(&tracenode);
582 * Return true if caller has permission to set the ktracing state
583 * of target. Essentially, the target can't possess any
584 * more permissions than the caller. KTRFAC_ROOT signifies that
585 * root previously set the tracing status on the target process, and
586 * so, only root may further change it.
588 * TODO: check groups. use caller effective gid.
591 ktrcanset(struct thread *calltd, struct proc *targetp)
593 struct ucred *caller = calltd->td_ucred;
594 struct ucred *target = targetp->p_ucred;
596 if (!PRISON_CHECK(caller, target))
598 if ((caller->cr_uid == target->cr_ruid &&
599 target->cr_ruid == target->cr_svuid &&
600 caller->cr_rgid == target->cr_rgid && /* XXX */
601 target->cr_rgid == target->cr_svgid &&
602 (targetp->p_traceflag & KTRFAC_ROOT) == 0 &&
603 (targetp->p_flag & P_SUGID) == 0) ||