[unix-history] / sys / kern / kern_ktrace.c

/*
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)kern_ktrace.c	7.15 (Berkeley) 6/21/91
 */

#ifdef KTRACE

#include "param.h"
#include "systm.h"
#include "proc.h"
#include "file.h"
#include "namei.h"
#include "vnode.h"
#include "ktrace.h"
#include "malloc.h"
#include "syslog.h"

struct ktr_header *
ktrgetheader(type)
{
	register struct ktr_header *kth;
	struct proc *p = curproc;	/* XXX */

	MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header), 
		M_TEMP, M_WAITOK);
	kth->ktr_type = type;
	microtime(&kth->ktr_time);
	kth->ktr_pid = p->p_pid;
	bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN);
	return (kth);
}

ktrsyscall(vp, code, narg, args)
	struct vnode *vp;
	int code, narg, args[];
{
	struct	ktr_header *kth = ktrgetheader(KTR_SYSCALL);
	struct	ktr_syscall *ktp;
	register len = sizeof(struct ktr_syscall) + (narg * sizeof(int));
	int 	*argp, i;

	MALLOC(ktp, struct ktr_syscall *, len, M_TEMP, M_WAITOK);
	ktp->ktr_code = code;
	ktp->ktr_narg = narg;
	argp = (int *)((char *)ktp + sizeof(struct ktr_syscall));
	for (i = 0; i < narg; i++)
		*argp++ = args[i];
	kth->ktr_buf = (caddr_t)ktp;
	kth->ktr_len = len;
	ktrwrite(vp, kth);
	FREE(ktp, M_TEMP);
	FREE(kth, M_TEMP);
}

ktrsysret(vp, code, error, retval)
	struct vnode *vp;
	int code, error, retval;
{
	struct ktr_header *kth = ktrgetheader(KTR_SYSRET);
	struct ktr_sysret ktp;

	ktp.ktr_code = code;
	ktp.ktr_error = error;
	ktp.ktr_retval = retval;		/* what about val2 ? */

	kth->ktr_buf = (caddr_t)&ktp;
	kth->ktr_len = sizeof(struct ktr_sysret);

	ktrwrite(vp, kth);
	FREE(kth, M_TEMP);
}

ktrnamei(vp, path)
	struct vnode *vp;
	char *path;
{
	struct ktr_header *kth = ktrgetheader(KTR_NAMEI);

	kth->ktr_len = strlen(path);
	kth->ktr_buf = path;

	ktrwrite(vp, kth);
	FREE(kth, M_TEMP);
}

ktrgenio(vp, fd, rw, iov, len, error)
	struct vnode *vp;
	int fd;
	enum uio_rw rw;
	register struct iovec *iov;
{
	struct ktr_header *kth = ktrgetheader(KTR_GENIO);
	register struct ktr_genio *ktp;
	register caddr_t cp;
	register int resid = len, cnt;
	
	if (error)
		return;
	MALLOC(ktp, struct ktr_genio *, sizeof(struct ktr_genio) + len,
		M_TEMP, M_WAITOK);
	ktp->ktr_fd = fd;
	ktp->ktr_rw = rw;
	cp = (caddr_t)((char *)ktp + sizeof (struct ktr_genio));
	while (resid > 0) {
		if ((cnt = iov->iov_len) > resid)
			cnt = resid;
		if (copyin(iov->iov_base, cp, (unsigned)cnt))
			goto done;
		cp += cnt;
		resid -= cnt;
		iov++;
	}
	kth->ktr_buf = (caddr_t)ktp;
	kth->ktr_len = sizeof (struct ktr_genio) + len;

	ktrwrite(vp, kth);
done:
	FREE(kth, M_TEMP);
	FREE(ktp, M_TEMP);
}

ktrpsig(vp, sig, action, mask, code)
	struct	vnode *vp;
	sig_t	action;
{
	struct ktr_header *kth = ktrgetheader(KTR_PSIG);
	struct ktr_psig	kp;

	kp.signo = (char)sig;
	kp.action = action;
	kp.mask = mask;
	kp.code = code;
	kth->ktr_buf = (caddr_t)&kp;
	kth->ktr_len = sizeof (struct ktr_psig);

	ktrwrite(vp, kth);
	FREE(kth, M_TEMP);
}

/* Interface and common routines */

/*
 * ktrace system call
 */

struct ktrace_args {
	char	*fname;
	int	ops;
	int	facs;
	int	pid;
};

/* ARGSUSED */
ktrace(curp, uap, retval)
	struct proc *curp;
	register struct ktrace_args *uap;
	int *retval;
{
	register struct vnode *vp = NULL;
	register struct proc *p;
	struct pgrp *pg;
	int facs = uap->facs & ~KTRFAC_ROOT;
	int ops = KTROP(uap->ops);
	int descend = uap->ops & KTRFLAG_DESCEND;
	int ret = 0;
	int error = 0;
	struct nameidata nd;

	if (ops != KTROP_CLEAR) {
		/*
		 * an operation which requires a file argument.
		 */
		nd.ni_segflg = UIO_USERSPACE;
		nd.ni_dirp = uap->fname;
		if (error = vn_open(&nd, curp, FREAD|FWRITE, 0))
			return (error);
		vp = nd.ni_vp;
		VOP_UNLOCK(vp);
		if (vp->v_type != VREG) {
			(void) vn_close(vp, FREAD|FWRITE, curp->p_ucred, curp);
			return (EACCES);
		}
	}
	/*
	 * Clear all uses of the tracefile
	 */
	if (ops == KTROP_CLEARFILE) {
		for (p = allproc; p != NULL; p = p->p_nxt) {
			if (p->p_tracep == vp) {
				if (ktrcanset(curp, p)) {
					p->p_tracep = NULL;
					p->p_traceflag = 0;
					(void) vn_close(vp, FREAD|FWRITE,
						p->p_ucred, p);
				} else
					error = EPERM;
			}
		}
		goto done;
	}
	/*
	 * need something to (un)trace (XXX - why is this here?)
	 */
	if (!facs) {
		error = EINVAL;
		goto done;
	}
	/* 
	 * do it
	 */
	if (uap->pid < 0) {
		/*
		 * by process group
		 */
		pg = pgfind(-uap->pid);
		if (pg == NULL) {
			error = ESRCH;
			goto done;
		}
		for (p = pg->pg_mem; p != NULL; p = p->p_pgrpnxt)
			if (descend)
				ret |= ktrsetchildren(curp, p, ops, facs, vp);
			else 
				ret |= ktrops(curp, p, ops, facs, vp);
					
	} else {
		/*
		 * by pid
		 */
		p = pfind(uap->pid);
		if (p == NULL) {
			error = ESRCH;
			goto done;
		}
		if (descend)
			ret |= ktrsetchildren(curp, p, ops, facs, vp);
		else
			ret |= ktrops(curp, p, ops, facs, vp);
	}
	if (!ret)
		error = EPERM;
done:
	if (vp != NULL)
		(void) vn_close(vp, FWRITE, curp->p_ucred, curp);
	return (error);
}

ktrops(curp, p, ops, facs, vp)
	struct proc *curp, *p;
	struct vnode *vp;
{

	if (!ktrcanset(curp, p))
		return (0);
	if (ops == KTROP_SET) {
		if (p->p_tracep != vp) { 
			/*
			 * if trace file already in use, relinquish
			 */
			if (p->p_tracep != NULL)
				vrele(p->p_tracep);
			VREF(vp);
			p->p_tracep = vp;
		}
		p->p_traceflag |= facs;
		if (curp->p_ucred->cr_uid == 0)
			p->p_traceflag |= KTRFAC_ROOT;
	} else {	
		/* KTROP_CLEAR */
		if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
			/* no more tracing */
			p->p_traceflag = 0;
			if (p->p_tracep != NULL) {
				vrele(p->p_tracep);
				p->p_tracep = NULL;
			}
		}
	}

	return (1);
}

ktrsetchildren(curp, top, ops, facs, vp)
	struct proc *curp, *top;
	struct vnode *vp;
{
	register struct proc *p;
	register int ret = 0;

	p = top;
	for (;;) {
		ret |= ktrops(curp, p, ops, facs, vp);
		/*
		 * If this process has children, descend to them next,
		 * otherwise do any siblings, and if done with this level,
		 * follow back up the tree (but not past top).
		 */
		if (p->p_cptr)
			p = p->p_cptr;
		else if (p == top)
			return (ret);
		else if (p->p_osptr)
			p = p->p_osptr;
		else for (;;) {
			p = p->p_pptr;
			if (p == top)
				return (ret);
			if (p->p_osptr) {
				p = p->p_osptr;
				break;
			}
		}
	}
	/*NOTREACHED*/
}

ktrwrite(vp, kth)
	struct vnode *vp;
	register struct ktr_header *kth;
{
	struct uio auio;
	struct iovec aiov[2];
	register struct proc *p = curproc;	/* XXX */
	int error;

	if (vp == NULL)
		return;
	auio.uio_iov = &aiov[0];
	auio.uio_offset = 0;
	auio.uio_segflg = UIO_SYSSPACE;
	auio.uio_rw = UIO_WRITE;
	aiov[0].iov_base = (caddr_t)kth;
	aiov[0].iov_len = sizeof(struct ktr_header);
	auio.uio_resid = sizeof(struct ktr_header);
	auio.uio_iovcnt = 1;
	auio.uio_procp = (struct proc *)0;
	if (kth->ktr_len > 0) {
		auio.uio_iovcnt++;
		aiov[1].iov_base = kth->ktr_buf;
		aiov[1].iov_len = kth->ktr_len;
		auio.uio_resid += kth->ktr_len;
	}
	VOP_LOCK(vp);
	error = VOP_WRITE(vp, &auio, IO_UNIT|IO_APPEND, p->p_ucred);
	VOP_UNLOCK(vp);
	if (!error)
		return;
	/*
	 * If error encountered, give up tracing on this vnode.
	 */
	log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n",
	    error);
	for (p = allproc; p != NULL; p = p->p_nxt) {
		if (p->p_tracep == vp) {
			p->p_tracep = NULL;
			p->p_traceflag = 0;
			vrele(vp);
		}
	}
}

/*
 * Return true if caller has permission to set the ktracing state
 * of target.  Essentially, the target can't possess any
 * more permissions than the caller.  KTRFAC_ROOT signifies that
 * root previously set the tracing status on the target process, and 
 * so, only root may further change it.
 *
 * TODO: check groups.  use caller effective gid.
 */
ktrcanset(callp, targetp)
	struct proc *callp, *targetp;
{
	register struct pcred *caller = callp->p_cred;
	register struct pcred *target = targetp->p_cred;

	if ((caller->pc_ucred->cr_uid == target->p_ruid &&
	     target->p_ruid == target->p_svuid &&
	     caller->p_rgid == target->p_rgid &&	/* XXX */
	     target->p_rgid == target->p_svgid &&
	     (targetp->p_traceflag & KTRFAC_ROOT) == 0) ||
	     caller->pc_ucred->cr_uid == 0)
		return (1);

	return (0);
}

#endif
Commit	Line	Data
15637ed4 RG	1	/*
	2	* Copyright (c) 1989 The Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	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. All advertising materials mentioning features or use of this software
	14	* must display the following acknowledgement:
	15	* This product includes software developed by the University of
	16	* California, Berkeley and its contributors.
	17	* 4. Neither the name of the University nor the names of its contributors
	18	* may be used to endorse or promote products derived from this software
	19	* without specific prior written permission.
	20	*
	21	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	22	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	23	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	24	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	25	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	26	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	27	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	28	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	29	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	30	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	31	* SUCH DAMAGE.
	32	*
	33	* @(#)kern_ktrace.c 7.15 (Berkeley) 6/21/91
	34	*/
	35
	36	#ifdef KTRACE
	37
	38	#include "param.h"
dd18dc33	39	#include "systm.h"
15637ed4 RG	40	#include "proc.h"
	41	#include "file.h"
	42	#include "namei.h"
	43	#include "vnode.h"
	44	#include "ktrace.h"
	45	#include "malloc.h"
	46	#include "syslog.h"
	47
	48	struct ktr_header *
	49	ktrgetheader(type)
	50	{
	51	register struct ktr_header *kth;
	52	struct proc p = curproc; / XXX */
	53
	54	MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header),
	55	M_TEMP, M_WAITOK);
	56	kth->ktr_type = type;
	57	microtime(&kth->ktr_time);
	58	kth->ktr_pid = p->p_pid;
	59	bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN);
	60	return (kth);
	61	}
	62
	63	ktrsyscall(vp, code, narg, args)
	64	struct vnode *vp;
	65	int code, narg, args[];
	66	{
	67	struct ktr_header *kth = ktrgetheader(KTR_SYSCALL);
	68	struct ktr_syscall *ktp;
	69	register len = sizeof(struct ktr_syscall) + (narg * sizeof(int));
	70	int *argp, i;
	71
	72	MALLOC(ktp, struct ktr_syscall *, len, M_TEMP, M_WAITOK);
	73	ktp->ktr_code = code;
	74	ktp->ktr_narg = narg;
	75	argp = (int )((char )ktp + sizeof(struct ktr_syscall));
	76	for (i = 0; i < narg; i++)
	77	*argp++ = args[i];
	78	kth->ktr_buf = (caddr_t)ktp;
	79	kth->ktr_len = len;
	80	ktrwrite(vp, kth);
	81	FREE(ktp, M_TEMP);
	82	FREE(kth, M_TEMP);
	83	}
	84
	85	ktrsysret(vp, code, error, retval)
	86	struct vnode *vp;
	87	int code, error, retval;
	88	{
	89	struct ktr_header *kth = ktrgetheader(KTR_SYSRET);
	90	struct ktr_sysret ktp;
	91
	92	ktp.ktr_code = code;
	93	ktp.ktr_error = error;
	94	ktp.ktr_retval = retval; /* what about val2 ? */
	95
	96	kth->ktr_buf = (caddr_t)&ktp;
	97	kth->ktr_len = sizeof(struct ktr_sysret);
	98
	99	ktrwrite(vp, kth);
	100	FREE(kth, M_TEMP);
	101	}
	102
	103	ktrnamei(vp, path)
104	struct vnode *vp;
105	char *path;
106	{
107	struct ktr_header *kth = ktrgetheader(KTR_NAMEI);
108
109	kth->ktr_len = strlen(path);
110	kth->ktr_buf = path;
111
112	ktrwrite(vp, kth);
113	FREE(kth, M_TEMP);
114	}
115
116	ktrgenio(vp, fd, rw, iov, len, error)
117	struct vnode *vp;
118	int fd;
119	enum uio_rw rw;
120	register struct iovec *iov;
121	{
122	struct ktr_header *kth = ktrgetheader(KTR_GENIO);
123	register struct ktr_genio *ktp;
124	register caddr_t cp;
125	register int resid = len, cnt;
126
127	if (error)
128	return;
129	MALLOC(ktp, struct ktr_genio *, sizeof(struct ktr_genio) + len,
130	M_TEMP, M_WAITOK);
131	ktp->ktr_fd = fd;
132	ktp->ktr_rw = rw;
133	cp = (caddr_t)((char *)ktp + sizeof (struct ktr_genio));
134	while (resid > 0) {
135	if ((cnt = iov->iov_len) > resid)
136	cnt = resid;
137	if (copyin(iov->iov_base, cp, (unsigned)cnt))
138	goto done;
139	cp += cnt;
140	resid -= cnt;
141	iov++;
142	}
143	kth->ktr_buf = (caddr_t)ktp;
144	kth->ktr_len = sizeof (struct ktr_genio) + len;
145
146	ktrwrite(vp, kth);
147	done:
148	FREE(kth, M_TEMP);
149	FREE(ktp, M_TEMP);
150	}
151
152	ktrpsig(vp, sig, action, mask, code)
153	struct vnode *vp;
154	sig_t action;
155	{
156	struct ktr_header *kth = ktrgetheader(KTR_PSIG);
157	struct ktr_psig kp;
158
159	kp.signo = (char)sig;
160	kp.action = action;
161	kp.mask = mask;
162	kp.code = code;
163	kth->ktr_buf = (caddr_t)&kp;
164	kth->ktr_len = sizeof (struct ktr_psig);
165
166	ktrwrite(vp, kth);
167	FREE(kth, M_TEMP);
168	}
169
170	/* Interface and common routines */
171
172	/*
173	* ktrace system call
174	*/
3c7eb27c DG	175
	176	struct ktrace_args {
	177	char *fname;
	178	int ops;
	179	int facs;
	180	int pid;
	181	};
	182
15637ed4 RG	183	/* ARGSUSED */
	184	ktrace(curp, uap, retval)
	185	struct proc *curp;
3c7eb27c	186	register struct ktrace_args *uap;
15637ed4 RG	187	int *retval;
	188	{
	189	register struct vnode *vp = NULL;
	190	register struct proc *p;
	191	struct pgrp *pg;
	192	int facs = uap->facs & ~KTRFAC_ROOT;
	193	int ops = KTROP(uap->ops);
	194	int descend = uap->ops & KTRFLAG_DESCEND;
	195	int ret = 0;
	196	int error = 0;
	197	struct nameidata nd;
	198
	199	if (ops != KTROP_CLEAR) {
	200	/*
	201	* an operation which requires a file argument.
	202	*/
	203	nd.ni_segflg = UIO_USERSPACE;
	204	nd.ni_dirp = uap->fname;
	205	if (error = vn_open(&nd, curp, FREAD\|FWRITE, 0))
	206	return (error);
	207	vp = nd.ni_vp;
	208	VOP_UNLOCK(vp);
	209	if (vp->v_type != VREG) {
	210	(void) vn_close(vp, FREAD\|FWRITE, curp->p_ucred, curp);
	211	return (EACCES);
	212	}
	213	}
	214	/*
	215	* Clear all uses of the tracefile
	216	*/
	217	if (ops == KTROP_CLEARFILE) {
	218	for (p = allproc; p != NULL; p = p->p_nxt) {
	219	if (p->p_tracep == vp) {
	220	if (ktrcanset(curp, p)) {
	221	p->p_tracep = NULL;
	222	p->p_traceflag = 0;
	223	(void) vn_close(vp, FREAD\|FWRITE,
	224	p->p_ucred, p);
	225	} else
	226	error = EPERM;
	227	}
	228	}
	229	goto done;
	230	}
	231	/*
	232	* need something to (un)trace (XXX - why is this here?)
	233	*/
	234	if (!facs) {
	235	error = EINVAL;
	236	goto done;
	237	}
	238	/*
	239	* do it
	240	*/
	241	if (uap->pid < 0) {
	242	/*
	243	* by process group
	244	*/
	245	pg = pgfind(-uap->pid);
	246	if (pg == NULL) {
	247	error = ESRCH;
	248	goto done;
	249	}
	250	for (p = pg->pg_mem; p != NULL; p = p->p_pgrpnxt)
251	if (descend)
252	ret \|= ktrsetchildren(curp, p, ops, facs, vp);
253	else
254	ret \|= ktrops(curp, p, ops, facs, vp);
255
256	} else {
257	/*
258	* by pid
259	*/
260	p = pfind(uap->pid);
261	if (p == NULL) {
262	error = ESRCH;
263	goto done;
264	}
265	if (descend)
266	ret \|= ktrsetchildren(curp, p, ops, facs, vp);
267	else
268	ret \|= ktrops(curp, p, ops, facs, vp);
269	}
270	if (!ret)
271	error = EPERM;
272	done:
273	if (vp != NULL)
274	(void) vn_close(vp, FWRITE, curp->p_ucred, curp);
275	return (error);
276	}
277
278	ktrops(curp, p, ops, facs, vp)
279	struct proc curp, p;
280	struct vnode *vp;
281	{
282
283	if (!ktrcanset(curp, p))
284	return (0);
285	if (ops == KTROP_SET) {
286	if (p->p_tracep != vp) {
287	/*
288	* if trace file already in use, relinquish
289	*/
290	if (p->p_tracep != NULL)
291	vrele(p->p_tracep);
292	VREF(vp);
293	p->p_tracep = vp;
294	}
295	p->p_traceflag \|= facs;
296	if (curp->p_ucred->cr_uid == 0)
297	p->p_traceflag \|= KTRFAC_ROOT;
298	} else {
299	/* KTROP_CLEAR */
300	if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
301	/* no more tracing */
302	p->p_traceflag = 0;
303	if (p->p_tracep != NULL) {
304	vrele(p->p_tracep);
305	p->p_tracep = NULL;
306	}
307	}
308	}
309
310	return (1);
311	}
312
313	ktrsetchildren(curp, top, ops, facs, vp)
314	struct proc curp, top;
315	struct vnode *vp;
316	{
317	register struct proc *p;
318	register int ret = 0;
319
320	p = top;
321	for (;;) {
322	ret \|= ktrops(curp, p, ops, facs, vp);
323	/*
324	* If this process has children, descend to them next,
325	* otherwise do any siblings, and if done with this level,
326	* follow back up the tree (but not past top).
327	*/
328	if (p->p_cptr)
329	p = p->p_cptr;
330	else if (p == top)
331	return (ret);
332	else if (p->p_osptr)
333	p = p->p_osptr;
334	else for (;;) {
335	p = p->p_pptr;
336	if (p == top)
337	return (ret);
338	if (p->p_osptr) {
339	p = p->p_osptr;
340	break;
341	}
342	}
343	}
344	/NOTREACHED/
345	}
346
347	ktrwrite(vp, kth)
348	struct vnode *vp;
349	register struct ktr_header *kth;
350	{
351	struct uio auio;
352	struct iovec aiov[2];
353	register struct proc p = curproc; / XXX */
354	int error;
355
356	if (vp == NULL)
357	return;
358	auio.uio_iov = &aiov[0];
359	auio.uio_offset = 0;
360	auio.uio_segflg = UIO_SYSSPACE;
361	auio.uio_rw = UIO_WRITE;
362	aiov[0].iov_base = (caddr_t)kth;
363	aiov[0].iov_len = sizeof(struct ktr_header);
364	auio.uio_resid = sizeof(struct ktr_header);
365	auio.uio_iovcnt = 1;
366	auio.uio_procp = (struct proc *)0;
367	if (kth->ktr_len > 0) {
368	auio.uio_iovcnt++;
369	aiov[1].iov_base = kth->ktr_buf;
370	aiov[1].iov_len = kth->ktr_len;
371	auio.uio_resid += kth->ktr_len;
372	}
373	VOP_LOCK(vp);
374	error = VOP_WRITE(vp, &auio, IO_UNIT\|IO_APPEND, p->p_ucred);
375	VOP_UNLOCK(vp);
376	if (!error)
377	return;
378	/*
379	* If error encountered, give up tracing on this vnode.
380	*/
381	log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n",
382	error);
383	for (p = allproc; p != NULL; p = p->p_nxt) {
384	if (p->p_tracep == vp) {
385	p->p_tracep = NULL;
386	p->p_traceflag = 0;
387	vrele(vp);
388	}
389	}
390	}
391
392	/*
393	* Return true if caller has permission to set the ktracing state
394	* of target. Essentially, the target can't possess any
395	* more permissions than the caller. KTRFAC_ROOT signifies that
396	* root previously set the tracing status on the target process, and
397	* so, only root may further change it.
398	*
399	* TODO: check groups. use caller effective gid.
400	*/
401	ktrcanset(callp, targetp)
402	struct proc callp, targetp;
403	{
404	register struct pcred *caller = callp->p_cred;
405	register struct pcred *target = targetp->p_cred;
406
407	if ((caller->pc_ucred->cr_uid == target->p_ruid &&
408	target->p_ruid == target->p_svuid &&
409	caller->p_rgid == target->p_rgid && /* XXX */
410	target->p_rgid == target->p_svgid &&
411	(targetp->p_traceflag & KTRFAC_ROOT) == 0) \|\|
412	caller->pc_ucred->cr_uid == 0)
413	return (1);
414
415	return (0);
416	}
417
418	#endif