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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 1.28 2006/08/12 00:26:20 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 */
70 MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header),
73 microtime(&kth->ktr_time);
74 kth->ktr_pid = p->p_pid;
75 bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN + 1);
80 ktrsyscall(struct proc *p, int code, int narg, register_t args[])
82 struct ktr_header *kth;
83 struct ktr_syscall *ktp;
88 len = offsetof(struct ktr_syscall, ktr_args) +
89 (narg * sizeof(register_t));
92 * Setting the active bit prevents a ktrace recursion from the
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(p, kth, NULL);
108 p->p_traceflag &= ~KTRFAC_ACTIVE;
112 ktrsysret(struct proc *p, int code, int error, register_t retval)
114 struct ktr_header *kth;
115 struct ktr_sysret ktp;
117 p->p_traceflag |= KTRFAC_ACTIVE;
118 kth = ktrgetheader(KTR_SYSRET);
120 ktp.ktr_error = error;
121 ktp.ktr_retval = retval; /* what about val2 ? */
123 kth->ktr_buf = (caddr_t)&ktp;
124 kth->ktr_len = sizeof(struct ktr_sysret);
126 ktrwrite(p, kth, NULL);
128 p->p_traceflag &= ~KTRFAC_ACTIVE;
132 ktrnamei(struct proc *p, char *path)
134 struct ktr_header *kth;
136 p->p_traceflag |= KTRFAC_ACTIVE;
137 kth = ktrgetheader(KTR_NAMEI);
138 kth->ktr_len = strlen(path);
141 ktrwrite(p, kth, NULL);
143 p->p_traceflag &= ~KTRFAC_ACTIVE;
147 ktrgenio(struct proc *p, int fd, enum uio_rw rw, struct uio *uio, int error)
149 struct ktr_header *kth;
150 struct ktr_genio ktg;
154 p->p_traceflag |= KTRFAC_ACTIVE;
155 kth = ktrgetheader(KTR_GENIO);
158 kth->ktr_buf = (caddr_t)&ktg;
159 kth->ktr_len = sizeof(struct ktr_genio);
161 uio->uio_rw = UIO_WRITE;
163 ktrwrite(p, kth, uio);
165 p->p_traceflag &= ~KTRFAC_ACTIVE;
169 ktrpsig(struct proc *p, int sig, sig_t action, sigset_t *mask, int code)
171 struct ktr_header *kth;
174 p->p_traceflag |= KTRFAC_ACTIVE;
175 kth = ktrgetheader(KTR_PSIG);
176 kp.signo = (char)sig;
180 kth->ktr_buf = (caddr_t)&kp;
181 kth->ktr_len = sizeof (struct ktr_psig);
183 ktrwrite(p, kth, NULL);
185 p->p_traceflag &= ~KTRFAC_ACTIVE;
189 ktrcsw(struct proc *p, int out, int user)
191 struct ktr_header *kth;
194 p->p_traceflag |= KTRFAC_ACTIVE;
195 kth = ktrgetheader(KTR_CSW);
198 kth->ktr_buf = (caddr_t)&kc;
199 kth->ktr_len = sizeof (struct ktr_csw);
201 ktrwrite(p, kth, NULL);
203 p->p_traceflag &= ~KTRFAC_ACTIVE;
207 /* Interface and common routines */
213 struct ktrace_clear_info {
214 ktrace_node_t tracenode;
219 static int ktrace_clear_callback(struct proc *p, void *data);
224 sys_ktrace(struct ktrace_args *uap)
227 struct ktrace_clear_info info;
228 struct thread *td = curthread;
229 struct proc *curp = td->td_proc;
232 int facs = uap->facs & ~KTRFAC_ROOT;
233 int ops = KTROP(uap->ops);
234 int descend = uap->ops & KTRFLAG_DESCEND;
237 struct nlookupdata nd;
238 ktrace_node_t tracenode = NULL;
240 curp->p_traceflag |= KTRFAC_ACTIVE;
241 if (ops != KTROP_CLEAR) {
243 * an operation which requires a file argument.
245 error = nlookup_init(&nd, uap->fname,
246 UIO_USERSPACE, NLC_LOCKVP);
248 error = vn_open(&nd, NULL, FREAD|FWRITE|O_NOFOLLOW, 0);
249 if (error == 0 && nd.nl_open_vp->v_type != VREG)
252 curp->p_traceflag &= ~KTRFAC_ACTIVE;
256 MALLOC(tracenode, ktrace_node_t, sizeof (struct ktrace_node),
257 M_KTRACE, M_WAITOK | M_ZERO);
258 tracenode->kn_vp = nd.nl_open_vp;
259 tracenode->kn_refs = 1;
260 nd.nl_open_vp = NULL;
262 vn_unlock(tracenode->kn_vp);
265 * Clear all uses of the tracefile. Not the most efficient operation
268 if (ops == KTROP_CLEARFILE) {
269 info.tracenode = tracenode;
272 allproc_scan(ktrace_clear_callback, &info);
277 * need something to (un)trace (XXX - why is this here?)
290 pg = pgfind(-uap->pid);
295 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
297 ret |= ktrsetchildren(curp, p, ops, facs, tracenode);
299 ret |= ktrops(curp, p, ops, facs, tracenode);
311 ret |= ktrsetchildren(curp, p, ops, facs, tracenode);
313 ret |= ktrops(curp, p, ops, facs, tracenode);
319 ktrdestroy(&tracenode);
320 curp->p_traceflag &= ~KTRFAC_ACTIVE;
330 * NOTE: NOT MPSAFE (yet)
333 ktrace_clear_callback(struct proc *p, void *data)
335 struct ktrace_clear_info *info = data;
337 if (info->rootclear) {
338 if (p->p_tracenode == info->tracenode) {
339 ktrdestroy(&p->p_tracenode);
343 if (p->p_tracenode->kn_vp == info->tracenode->kn_vp) {
344 if (ktrcanset(curproc, p)) {
345 ktrdestroy(&p->p_tracenode);
362 sys_utrace(struct utrace_args *uap)
365 struct ktr_header *kth;
366 struct thread *td = curthread; /* XXX */
367 struct proc *p = td->td_proc;
370 if (!KTRPOINT(td, KTR_USER))
372 if (uap->len > KTR_USER_MAXLEN)
374 p->p_traceflag |= KTRFAC_ACTIVE;
375 kth = ktrgetheader(KTR_USER);
376 MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK);
377 if (!copyin(uap->addr, cp, uap->len)) {
379 kth->ktr_len = uap->len;
380 ktrwrite(p, kth, NULL);
384 p->p_traceflag &= ~KTRFAC_ACTIVE;
393 ktrdestroy(struct ktrace_node **tracenodep)
395 ktrace_node_t tracenode;
397 if ((tracenode = *tracenodep) != NULL) {
399 KKASSERT(tracenode->kn_refs > 0);
400 /* XXX not MP safe yet */
401 --tracenode->kn_refs;
402 if (tracenode->kn_refs == 0) {
403 vn_close(tracenode->kn_vp, FREAD|FWRITE);
404 tracenode->kn_vp = NULL;
405 FREE(tracenode, M_KTRACE);
411 * This allows a process to inherit a ref on a tracenode and is also used
412 * as a temporary ref to prevent a tracenode from being destroyed out from
413 * under an active operation.
416 ktrinherit(ktrace_node_t tracenode)
419 KKASSERT(tracenode->kn_refs > 0);
420 ++tracenode->kn_refs;
427 ktrops(struct proc *curp, struct proc *p, int ops, int facs,
428 ktrace_node_t tracenode)
430 ktrace_node_t oldnode;
432 if (!ktrcanset(curp, p))
434 if (ops == KTROP_SET) {
435 if ((oldnode = p->p_tracenode) != tracenode) {
436 p->p_tracenode = ktrinherit(tracenode);
437 ktrdestroy(&oldnode);
439 p->p_traceflag |= facs;
440 if (curp->p_ucred->cr_uid == 0)
441 p->p_traceflag |= KTRFAC_ROOT;
444 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
445 /* no more tracing */
447 ktrdestroy(&p->p_tracenode);
455 ktrsetchildren(struct proc *curp, struct proc *top, int ops, int facs,
456 ktrace_node_t tracenode)
463 ret |= ktrops(curp, p, ops, facs, tracenode);
465 * If this process has children, descend to them next,
466 * otherwise do any siblings, and if done with this level,
467 * follow back up the tree (but not past top).
469 if (!LIST_EMPTY(&p->p_children))
470 p = LIST_FIRST(&p->p_children);
474 if (LIST_NEXT(p, p_sibling)) {
475 p = LIST_NEXT(p, p_sibling);
485 ktrwrite(struct proc *p, struct ktr_header *kth, struct uio *uio)
487 struct ktrace_clear_info info;
489 struct iovec aiov[2];
491 ktrace_node_t tracenode;
494 * We have to ref our tracenode to prevent it from being ripped out
495 * from under us while we are trying to use it. p_tracenode can
496 * go away at any time if another process gets a write error.
500 if (p->p_tracenode == NULL)
502 tracenode = ktrinherit(p->p_tracenode);
503 auio.uio_iov = &aiov[0];
505 auio.uio_segflg = UIO_SYSSPACE;
506 auio.uio_rw = UIO_WRITE;
507 aiov[0].iov_base = (caddr_t)kth;
508 aiov[0].iov_len = sizeof(struct ktr_header);
509 auio.uio_resid = sizeof(struct ktr_header);
511 auio.uio_td = curthread;
512 if (kth->ktr_len > 0) {
514 aiov[1].iov_base = kth->ktr_buf;
515 aiov[1].iov_len = kth->ktr_len;
516 auio.uio_resid += kth->ktr_len;
518 kth->ktr_len += uio->uio_resid;
520 vn_lock(tracenode->kn_vp, LK_EXCLUSIVE | LK_RETRY);
521 error = VOP_WRITE(tracenode->kn_vp, &auio,
522 IO_UNIT | IO_APPEND, p->p_ucred);
523 if (error == 0 && uio != NULL) {
524 error = VOP_WRITE(tracenode->kn_vp, uio,
525 IO_UNIT | IO_APPEND, p->p_ucred);
527 vn_unlock(tracenode->kn_vp);
530 * If an error occured, give up tracing on all processes
531 * using this tracenode. This is not MP safe but is
535 "ktrace write failed, errno %d, tracing stopped\n", error);
536 info.tracenode = tracenode;
539 allproc_scan(ktrace_clear_callback, &info);
541 ktrdestroy(&tracenode);
545 * Return true if caller has permission to set the ktracing state
546 * of target. Essentially, the target can't possess any
547 * more permissions than the caller. KTRFAC_ROOT signifies that
548 * root previously set the tracing status on the target process, and
549 * so, only root may further change it.
551 * TODO: check groups. use caller effective gid.
554 ktrcanset(struct proc *callp, struct proc *targetp)
556 struct ucred *caller = callp->p_ucred;
557 struct ucred *target = targetp->p_ucred;
559 if (!PRISON_CHECK(caller, target))
561 if ((caller->cr_uid == target->cr_ruid &&
562 target->cr_ruid == target->cr_svuid &&
563 caller->cr_rgid == target->cr_rgid && /* XXX */
564 target->cr_rgid == target->cr_svgid &&
565 (targetp->p_traceflag & KTRFAC_ROOT) == 0 &&
566 (targetp->p_flag & P_SUGID) == 0) ||