[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.
 *
 *	from: @(#)kern_ktrace.c	7.15 (Berkeley) 6/21/91
 *	$Id$
 */

#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	*
600f7f07 RG	33	* from: @(#)kern_ktrace.c 7.15 (Berkeley) 6/21/91
600f7f07 RG	34	* $Id$
15637ed4 RG	35	*/
	36
	37	#ifdef KTRACE
	38
	39	#include "param.h"
dd18dc33	40	#include "systm.h"
15637ed4 RG	41	#include "proc.h"
	42	#include "file.h"
	43	#include "namei.h"
	44	#include "vnode.h"
	45	#include "ktrace.h"
	46	#include "malloc.h"
	47	#include "syslog.h"
	48
	49	struct ktr_header *
	50	ktrgetheader(type)
	51	{
	52	register struct ktr_header *kth;
	53	struct proc p = curproc; / XXX */
	54
	55	MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header),
	56	M_TEMP, M_WAITOK);
	57	kth->ktr_type = type;
	58	microtime(&kth->ktr_time);
	59	kth->ktr_pid = p->p_pid;
	60	bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN);
	61	return (kth);
	62	}
	63
	64	ktrsyscall(vp, code, narg, args)
	65	struct vnode *vp;
	66	int code, narg, args[];
	67	{
	68	struct ktr_header *kth = ktrgetheader(KTR_SYSCALL);
	69	struct ktr_syscall *ktp;
	70	register len = sizeof(struct ktr_syscall) + (narg * sizeof(int));
	71	int *argp, i;
	72
	73	MALLOC(ktp, struct ktr_syscall *, len, M_TEMP, M_WAITOK);
	74	ktp->ktr_code = code;
	75	ktp->ktr_narg = narg;
	76	argp = (int )((char )ktp + sizeof(struct ktr_syscall));
	77	for (i = 0; i < narg; i++)
	78	*argp++ = args[i];
	79	kth->ktr_buf = (caddr_t)ktp;
	80	kth->ktr_len = len;
	81	ktrwrite(vp, kth);
	82	FREE(ktp, M_TEMP);
	83	FREE(kth, M_TEMP);
	84	}
	85
	86	ktrsysret(vp, code, error, retval)
	87	struct vnode *vp;
	88	int code, error, retval;
	89	{
	90	struct ktr_header *kth = ktrgetheader(KTR_SYSRET);
	91	struct ktr_sysret ktp;
	92
	93	ktp.ktr_code = code;
	94	ktp.ktr_error = error;
	95	ktp.ktr_retval = retval; /* what about val2 ? */
	96
	97	kth->ktr_buf = (caddr_t)&ktp;
	98	kth->ktr_len = sizeof(struct ktr_sysret);
	99
	100	ktrwrite(vp, kth);
	101	FREE(kth, M_TEMP);
	102	}
	103
	104	ktrnamei(vp, path)
105	struct vnode *vp;
106	char *path;
107	{
108	struct ktr_header *kth = ktrgetheader(KTR_NAMEI);
109
110	kth->ktr_len = strlen(path);
111	kth->ktr_buf = path;
112
113	ktrwrite(vp, kth);
114	FREE(kth, M_TEMP);
115	}
116
117	ktrgenio(vp, fd, rw, iov, len, error)
118	struct vnode *vp;
119	int fd;
120	enum uio_rw rw;
121	register struct iovec *iov;
122	{
123	struct ktr_header *kth = ktrgetheader(KTR_GENIO);
124	register struct ktr_genio *ktp;
125	register caddr_t cp;
126	register int resid = len, cnt;
127
128	if (error)
129	return;
130	MALLOC(ktp, struct ktr_genio *, sizeof(struct ktr_genio) + len,
131	M_TEMP, M_WAITOK);
132	ktp->ktr_fd = fd;
133	ktp->ktr_rw = rw;
134	cp = (caddr_t)((char *)ktp + sizeof (struct ktr_genio));
135	while (resid > 0) {
136	if ((cnt = iov->iov_len) > resid)
137	cnt = resid;
138	if (copyin(iov->iov_base, cp, (unsigned)cnt))
139	goto done;
140	cp += cnt;
141	resid -= cnt;
142	iov++;
143	}
144	kth->ktr_buf = (caddr_t)ktp;
145	kth->ktr_len = sizeof (struct ktr_genio) + len;
146
147	ktrwrite(vp, kth);
148	done:
149	FREE(kth, M_TEMP);
150	FREE(ktp, M_TEMP);
151	}
152
153	ktrpsig(vp, sig, action, mask, code)
154	struct vnode *vp;
155	sig_t action;
156	{
157	struct ktr_header *kth = ktrgetheader(KTR_PSIG);
158	struct ktr_psig kp;
159
160	kp.signo = (char)sig;
161	kp.action = action;
162	kp.mask = mask;
163	kp.code = code;
164	kth->ktr_buf = (caddr_t)&kp;
165	kth->ktr_len = sizeof (struct ktr_psig);
166
167	ktrwrite(vp, kth);
168	FREE(kth, M_TEMP);
169	}
170
171	/* Interface and common routines */
172
173	/*
174	* ktrace system call
175	*/
3c7eb27c DG	176
	177	struct ktrace_args {
	178	char *fname;
	179	int ops;
	180	int facs;
	181	int pid;
	182	};
	183
15637ed4 RG	184	/* ARGSUSED */
	185	ktrace(curp, uap, retval)
	186	struct proc *curp;
3c7eb27c	187	register struct ktrace_args *uap;
15637ed4 RG	188	int *retval;
	189	{
	190	register struct vnode *vp = NULL;
	191	register struct proc *p;
	192	struct pgrp *pg;
	193	int facs = uap->facs & ~KTRFAC_ROOT;
	194	int ops = KTROP(uap->ops);
	195	int descend = uap->ops & KTRFLAG_DESCEND;
	196	int ret = 0;
	197	int error = 0;
	198	struct nameidata nd;
	199
	200	if (ops != KTROP_CLEAR) {
	201	/*
	202	* an operation which requires a file argument.
	203	*/
	204	nd.ni_segflg = UIO_USERSPACE;
	205	nd.ni_dirp = uap->fname;
	206	if (error = vn_open(&nd, curp, FREAD\|FWRITE, 0))
	207	return (error);
	208	vp = nd.ni_vp;
	209	VOP_UNLOCK(vp);
	210	if (vp->v_type != VREG) {
	211	(void) vn_close(vp, FREAD\|FWRITE, curp->p_ucred, curp);
	212	return (EACCES);
	213	}
	214	}
	215	/*
	216	* Clear all uses of the tracefile
	217	*/
	218	if (ops == KTROP_CLEARFILE) {
	219	for (p = allproc; p != NULL; p = p->p_nxt) {
	220	if (p->p_tracep == vp) {
	221	if (ktrcanset(curp, p)) {
	222	p->p_tracep = NULL;
	223	p->p_traceflag = 0;
	224	(void) vn_close(vp, FREAD\|FWRITE,
	225	p->p_ucred, p);
	226	} else
	227	error = EPERM;
	228	}
	229	}
	230	goto done;
	231	}
	232	/*
	233	* need something to (un)trace (XXX - why is this here?)
	234	*/
	235	if (!facs) {
	236	error = EINVAL;
	237	goto done;
	238	}
	239	/*
	240	* do it
	241	*/
	242	if (uap->pid < 0) {
	243	/*
	244	* by process group
	245	*/
	246	pg = pgfind(-uap->pid);
	247	if (pg == NULL) {
	248	error = ESRCH;
	249	goto done;
	250	}
	251	for (p = pg->pg_mem; p != NULL; p = p->p_pgrpnxt)
252	if (descend)
253	ret \|= ktrsetchildren(curp, p, ops, facs, vp);
254	else
255	ret \|= ktrops(curp, p, ops, facs, vp);
256
257	} else {
258	/*
259	* by pid
260	*/
261	p = pfind(uap->pid);
262	if (p == NULL) {
263	error = ESRCH;
264	goto done;
265	}
266	if (descend)
267	ret \|= ktrsetchildren(curp, p, ops, facs, vp);
268	else
269	ret \|= ktrops(curp, p, ops, facs, vp);
270	}
271	if (!ret)
272	error = EPERM;
273	done:
274	if (vp != NULL)
275	(void) vn_close(vp, FWRITE, curp->p_ucred, curp);
276	return (error);
277	}
278
279	ktrops(curp, p, ops, facs, vp)
280	struct proc curp, p;
281	struct vnode *vp;
282	{
283
284	if (!ktrcanset(curp, p))
285	return (0);
286	if (ops == KTROP_SET) {
287	if (p->p_tracep != vp) {
288	/*
289	* if trace file already in use, relinquish
290	*/
291	if (p->p_tracep != NULL)
292	vrele(p->p_tracep);
293	VREF(vp);
294	p->p_tracep = vp;
295	}
296	p->p_traceflag \|= facs;
297	if (curp->p_ucred->cr_uid == 0)
298	p->p_traceflag \|= KTRFAC_ROOT;
299	} else {
300	/* KTROP_CLEAR */
301	if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
302	/* no more tracing */
303	p->p_traceflag = 0;
304	if (p->p_tracep != NULL) {
305	vrele(p->p_tracep);
306	p->p_tracep = NULL;
307	}
308	}
309	}
310
311	return (1);
312	}
313
314	ktrsetchildren(curp, top, ops, facs, vp)
315	struct proc curp, top;
316	struct vnode *vp;
317	{
318	register struct proc *p;
319	register int ret = 0;
320
321	p = top;
322	for (;;) {
323	ret \|= ktrops(curp, p, ops, facs, vp);
324	/*
325	* If this process has children, descend to them next,
326	* otherwise do any siblings, and if done with this level,
327	* follow back up the tree (but not past top).
328	*/
329	if (p->p_cptr)
330	p = p->p_cptr;
331	else if (p == top)
332	return (ret);
333	else if (p->p_osptr)
334	p = p->p_osptr;
335	else for (;;) {
336	p = p->p_pptr;
337	if (p == top)
338	return (ret);
339	if (p->p_osptr) {
340	p = p->p_osptr;
341	break;
342	}
343	}
344	}
345	/NOTREACHED/
346	}
347
348	ktrwrite(vp, kth)
349	struct vnode *vp;
350	register struct ktr_header *kth;
351	{
352	struct uio auio;
353	struct iovec aiov[2];
354	register struct proc p = curproc; / XXX */
355	int error;
356
357	if (vp == NULL)
358	return;
359	auio.uio_iov = &aiov[0];
360	auio.uio_offset = 0;
361	auio.uio_segflg = UIO_SYSSPACE;
362	auio.uio_rw = UIO_WRITE;
363	aiov[0].iov_base = (caddr_t)kth;
364	aiov[0].iov_len = sizeof(struct ktr_header);
365	auio.uio_resid = sizeof(struct ktr_header);
366	auio.uio_iovcnt = 1;
367	auio.uio_procp = (struct proc *)0;
368	if (kth->ktr_len > 0) {
369	auio.uio_iovcnt++;
370	aiov[1].iov_base = kth->ktr_buf;
371	aiov[1].iov_len = kth->ktr_len;
372	auio.uio_resid += kth->ktr_len;
373	}
374	VOP_LOCK(vp);
375	error = VOP_WRITE(vp, &auio, IO_UNIT\|IO_APPEND, p->p_ucred);
376	VOP_UNLOCK(vp);
377	if (!error)
378	return;
379	/*
380	* If error encountered, give up tracing on this vnode.
381	*/
382	log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n",
383	error);
384	for (p = allproc; p != NULL; p = p->p_nxt) {
385	if (p->p_tracep == vp) {
386	p->p_tracep = NULL;
387	p->p_traceflag = 0;
388	vrele(vp);
389	}
390	}
391	}
392
393	/*
394	* Return true if caller has permission to set the ktracing state
395	* of target. Essentially, the target can't possess any
396	* more permissions than the caller. KTRFAC_ROOT signifies that
397	* root previously set the tracing status on the target process, and
398	* so, only root may further change it.
399	*
400	* TODO: check groups. use caller effective gid.
401	*/
402	ktrcanset(callp, targetp)
403	struct proc callp, targetp;
404	{
405	register struct pcred *caller = callp->p_cred;
406	register struct pcred *target = targetp->p_cred;
407
408	if ((caller->pc_ucred->cr_uid == target->p_ruid &&
409	target->p_ruid == target->p_svuid &&
410	caller->p_rgid == target->p_rgid && /* XXX */
411	target->p_rgid == target->p_svgid &&
412	(targetp->p_traceflag & KTRFAC_ROOT) == 0) \|\|
413	caller->pc_ucred->cr_uid == 0)
414	return (1);
415
416	return (0);
417	}
418
419	#endif