freebsd-skq/sys/kern/kern_ktrace.c
jhb 418e247b74 - Change the first argument of ktrcanset(), ktrsetchildren(), and ktrops()
to a thread pointer so that ktrcanset() can use td_ucred.
- Add some proc locking to partially protect p_tracep and p_traceflag.
2002-04-13 22:54:18 +00:00

632 lines
14 KiB
C

/*
* Copyright (c) 1989, 1993
* 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 8.2 (Berkeley) 9/23/93
* $FreeBSD$
*/
#include "opt_ktrace.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sysproto.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/fcntl.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/ktrace.h>
#include <sys/malloc.h>
#include <sys/sx.h>
#include <sys/syslog.h>
#include <sys/jail.h>
static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE");
#ifdef KTRACE
static struct ktr_header *ktrgetheader(int type);
static void ktrwrite(struct vnode *, struct ktr_header *, struct uio *);
static int ktrcanset(struct thread *, struct proc *);
static int ktrsetchildren(struct thread *, struct proc *, int, int, struct vnode *);
static int ktrops(struct thread *, struct proc *, int, int, struct vnode *);
static struct ktr_header *
ktrgetheader(type)
int type;
{
register struct ktr_header *kth;
struct proc *p = curproc; /* XXX */
MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header),
M_KTRACE, M_WAITOK);
kth->ktr_type = type;
microtime(&kth->ktr_time);
kth->ktr_pid = p->p_pid;
bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN + 1);
return (kth);
}
/*
* MPSAFE
*/
void
ktrsyscall(vp, code, narg, args)
struct vnode *vp;
int code, narg;
register_t args[];
{
struct ktr_header *kth;
struct ktr_syscall *ktp;
register int len = offsetof(struct ktr_syscall, ktr_args) +
(narg * sizeof(register_t));
struct proc *p = curproc; /* XXX */
register_t *argp;
int i;
mtx_lock(&Giant);
p->p_traceflag |= KTRFAC_ACTIVE;
kth = ktrgetheader(KTR_SYSCALL);
MALLOC(ktp, struct ktr_syscall *, len, M_KTRACE, M_WAITOK);
ktp->ktr_code = code;
ktp->ktr_narg = narg;
argp = &ktp->ktr_args[0];
for (i = 0; i < narg; i++)
*argp++ = args[i];
kth->ktr_buffer = (caddr_t)ktp;
kth->ktr_len = len;
ktrwrite(vp, kth, NULL);
FREE(ktp, M_KTRACE);
FREE(kth, M_KTRACE);
p->p_traceflag &= ~KTRFAC_ACTIVE;
mtx_unlock(&Giant);
}
/*
* MPSAFE
*/
void
ktrsysret(vp, code, error, retval)
struct vnode *vp;
int code, error;
register_t retval;
{
struct ktr_header *kth;
struct ktr_sysret ktp;
struct proc *p = curproc; /* XXX */
mtx_lock(&Giant);
p->p_traceflag |= KTRFAC_ACTIVE;
kth = ktrgetheader(KTR_SYSRET);
ktp.ktr_code = code;
ktp.ktr_error = error;
ktp.ktr_retval = retval; /* what about val2 ? */
kth->ktr_buffer = (caddr_t)&ktp;
kth->ktr_len = sizeof(struct ktr_sysret);
ktrwrite(vp, kth, NULL);
FREE(kth, M_KTRACE);
p->p_traceflag &= ~KTRFAC_ACTIVE;
mtx_unlock(&Giant);
}
void
ktrnamei(vp, path)
struct vnode *vp;
char *path;
{
struct ktr_header *kth;
struct proc *p = curproc; /* XXX */
/*
* don't let p_tracep get ripped out from under us
*/
if (vp)
VREF(vp);
p->p_traceflag |= KTRFAC_ACTIVE;
kth = ktrgetheader(KTR_NAMEI);
kth->ktr_len = strlen(path);
kth->ktr_buffer = path;
ktrwrite(vp, kth, NULL);
if (vp)
vrele(vp);
FREE(kth, M_KTRACE);
p->p_traceflag &= ~KTRFAC_ACTIVE;
}
void
ktrgenio(vp, fd, rw, uio, error)
struct vnode *vp;
int fd;
enum uio_rw rw;
struct uio *uio;
int error;
{
struct ktr_header *kth;
struct ktr_genio ktg;
struct proc *p = curproc; /* XXX */
if (error)
return;
mtx_lock(&Giant);
/*
* don't let p_tracep get ripped out from under us
*/
if (vp)
VREF(vp);
p->p_traceflag |= KTRFAC_ACTIVE;
kth = ktrgetheader(KTR_GENIO);
ktg.ktr_fd = fd;
ktg.ktr_rw = rw;
kth->ktr_buffer = (caddr_t)&ktg;
kth->ktr_len = sizeof(struct ktr_genio);
uio->uio_offset = 0;
uio->uio_rw = UIO_WRITE;
ktrwrite(vp, kth, uio);
if (vp)
vrele(vp);
FREE(kth, M_KTRACE);
p->p_traceflag &= ~KTRFAC_ACTIVE;
mtx_unlock(&Giant);
}
void
ktrpsig(vp, sig, action, mask, code)
struct vnode *vp;
int sig;
sig_t action;
sigset_t *mask;
int code;
{
struct ktr_header *kth;
struct ktr_psig kp;
struct proc *p = curproc; /* XXX */
/*
* don't let vp get ripped out from under us
*/
if (vp)
VREF(vp);
p->p_traceflag |= KTRFAC_ACTIVE;
kth = ktrgetheader(KTR_PSIG);
kp.signo = (char)sig;
kp.action = action;
kp.mask = *mask;
kp.code = code;
kth->ktr_buffer = (caddr_t)&kp;
kth->ktr_len = sizeof (struct ktr_psig);
ktrwrite(vp, kth, NULL);
if (vp)
vrele(vp);
FREE(kth, M_KTRACE);
p->p_traceflag &= ~KTRFAC_ACTIVE;
}
void
ktrcsw(vp, out, user)
struct vnode *vp;
int out, user;
{
struct ktr_header *kth;
struct ktr_csw kc;
struct proc *p = curproc; /* XXX */
/*
* don't let vp get ripped out from under us
*/
if (vp)
VREF(vp);
p->p_traceflag |= KTRFAC_ACTIVE;
kth = ktrgetheader(KTR_CSW);
kc.out = out;
kc.user = user;
kth->ktr_buffer = (caddr_t)&kc;
kth->ktr_len = sizeof (struct ktr_csw);
ktrwrite(vp, kth, NULL);
if (vp)
vrele(vp);
FREE(kth, M_KTRACE);
p->p_traceflag &= ~KTRFAC_ACTIVE;
}
#endif
/* Interface and common routines */
/*
* ktrace system call
*/
#ifndef _SYS_SYSPROTO_H_
struct ktrace_args {
char *fname;
int ops;
int facs;
int pid;
};
#endif
/* ARGSUSED */
int
ktrace(td, uap)
struct thread *td;
register struct ktrace_args *uap;
{
#ifdef KTRACE
struct proc *curp = td->td_proc;
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 flags, error = 0;
struct nameidata nd;
curp->p_traceflag |= KTRFAC_ACTIVE;
if (ops != KTROP_CLEAR) {
/*
* an operation which requires a file argument.
*/
NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->fname, td);
flags = FREAD | FWRITE | O_NOFOLLOW;
error = vn_open(&nd, &flags, 0);
if (error) {
curp->p_traceflag &= ~KTRFAC_ACTIVE;
return (error);
}
NDFREE(&nd, NDF_ONLY_PNBUF);
vp = nd.ni_vp;
VOP_UNLOCK(vp, 0, td);
if (vp->v_type != VREG) {
(void) vn_close(vp, FREAD|FWRITE, td->td_ucred, td);
curp->p_traceflag &= ~KTRFAC_ACTIVE;
return (EACCES);
}
}
/*
* Clear all uses of the tracefile.
*/
if (ops == KTROP_CLEARFILE) {
sx_slock(&allproc_lock);
LIST_FOREACH(p, &allproc, p_list) {
PROC_LOCK(p);
if (p->p_tracep == vp) {
if (ktrcanset(td, p) && p->p_tracep == vp) {
p->p_tracep = NULL;
p->p_traceflag = 0;
PROC_UNLOCK(p);
(void) vn_close(vp, FREAD|FWRITE,
td->td_ucred, td);
} else {
PROC_UNLOCK(p);
error = EPERM;
}
} else
PROC_UNLOCK(p);
}
sx_sunlock(&allproc_lock);
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
*/
PGRPSESS_SLOCK();
pg = pgfind(-uap->pid);
if (pg == NULL) {
PGRPSESS_SUNLOCK();
error = ESRCH;
goto done;
}
/*
* ktrops() may call vrele(). Lock pg_members
* by the pgrpsess_lock rather than pg_mtx.
*/
PGRP_UNLOCK(pg);
LIST_FOREACH(p, &pg->pg_members, p_pglist)
if (descend)
ret |= ktrsetchildren(td, p, ops, facs, vp);
else
ret |= ktrops(td, p, ops, facs, vp);
PGRPSESS_SUNLOCK();
} else {
/*
* by pid
*/
p = pfind(uap->pid);
if (p == NULL) {
error = ESRCH;
goto done;
}
PROC_UNLOCK(p);
/* XXX: UNLOCK above has a race */
if (descend)
ret |= ktrsetchildren(td, p, ops, facs, vp);
else
ret |= ktrops(td, p, ops, facs, vp);
}
if (!ret)
error = EPERM;
done:
if (vp != NULL)
(void) vn_close(vp, FWRITE, td->td_ucred, td);
curp->p_traceflag &= ~KTRFAC_ACTIVE;
return (error);
#else
return ENOSYS;
#endif
}
/*
* utrace system call
*/
/* ARGSUSED */
int
utrace(td, uap)
struct thread *td;
register struct utrace_args *uap;
{
#ifdef KTRACE
struct ktr_header *kth;
struct proc *p = curproc; /* XXX */
struct vnode *vp;
register caddr_t cp;
if (!KTRPOINT(p, KTR_USER))
return (0);
if (uap->len > KTR_USER_MAXLEN)
return (EINVAL);
p->p_traceflag |= KTRFAC_ACTIVE;
if ((vp = p->p_tracep) != NULL)
VREF(vp);
kth = ktrgetheader(KTR_USER);
MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK);
if (!copyin(uap->addr, cp, uap->len)) {
kth->ktr_buffer = cp;
kth->ktr_len = uap->len;
ktrwrite(vp, kth, NULL);
}
if (vp)
vrele(vp);
FREE(kth, M_KTRACE);
FREE(cp, M_KTRACE);
p->p_traceflag &= ~KTRFAC_ACTIVE;
return (0);
#else
return (ENOSYS);
#endif
}
#ifdef KTRACE
static int
ktrops(td, p, ops, facs, vp)
struct thread *td;
struct proc *p;
int ops, facs;
struct vnode *vp;
{
struct vnode *vtmp = NULL, *newvp = NULL;
PROC_LOCK(p);
if (!ktrcanset(td, p)) {
PROC_UNLOCK(p);
return (0);
}
if (ops == KTROP_SET) {
if (p->p_tracep != vp) {
struct vnode *vtmp;
/*
* if trace file already in use, relinquish below
*/
newvp = vp;
vtmp = p->p_tracep;
p->p_tracep = NULL;
}
p->p_traceflag |= facs;
if (td->td_ucred->cr_uid == 0)
p->p_traceflag |= KTRFAC_ROOT;
} else {
/* KTROP_CLEAR */
if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
struct vnode *vtmp;
/* no more tracing */
p->p_traceflag = 0;
vtmp = p->p_tracep;
p->p_tracep = NULL;
}
}
PROC_UNLOCK(p);
/* Release old trace file if requested. */
if (vtmp != NULL)
vrele(vtmp);
/* Setup new trace file if requested. */
/*
* XXX: Doing this before the PROC_UNLOCK above would result in
* fewer lock operations but would break old behavior where the
* above vrele() would not be traced when changing trace files.
*/
if (newvp != NULL) {
VREF(newvp);
PROC_LOCK(p);
p->p_tracep = newvp;
PROC_UNLOCK(p);
}
return (1);
}
static int
ktrsetchildren(td, top, ops, facs, vp)
struct thread *td;
struct proc *top;
int ops, facs;
struct vnode *vp;
{
register struct proc *p;
register int ret = 0;
p = top;
sx_slock(&proctree_lock);
for (;;) {
ret |= ktrops(td, 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 (!LIST_EMPTY(&p->p_children))
p = LIST_FIRST(&p->p_children);
else for (;;) {
if (p == top) {
sx_sunlock(&proctree_lock);
return (ret);
}
if (LIST_NEXT(p, p_sibling)) {
p = LIST_NEXT(p, p_sibling);
break;
}
p = p->p_pptr;
}
}
/*NOTREACHED*/
}
static void
ktrwrite(vp, kth, uio)
struct vnode *vp;
register struct ktr_header *kth;
struct uio *uio;
{
struct uio auio;
struct iovec aiov[2];
struct thread *td = curthread; /* XXX */
struct proc *p = td->td_proc; /* XXX */
struct mount *mp;
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_td = curthread;
if (kth->ktr_len > 0) {
auio.uio_iovcnt++;
aiov[1].iov_base = kth->ktr_buffer;
aiov[1].iov_len = kth->ktr_len;
auio.uio_resid += kth->ktr_len;
if (uio != NULL)
kth->ktr_len += uio->uio_resid;
}
vn_start_write(vp, &mp, V_WAIT);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
(void)VOP_LEASE(vp, td, td->td_ucred, LEASE_WRITE);
error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, td->td_ucred);
if (error == 0 && uio != NULL) {
(void)VOP_LEASE(vp, td, td->td_ucred, LEASE_WRITE);
error = VOP_WRITE(vp, uio, IO_UNIT | IO_APPEND, td->td_ucred);
}
VOP_UNLOCK(vp, 0, td);
vn_finished_write(mp);
if (!error)
return;
/*
* If error encountered, give up tracing on this vnode. XXX what
* happens to the loop if vrele() blocks?
*/
log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n",
error);
sx_slock(&allproc_lock);
LIST_FOREACH(p, &allproc, p_list) {
if (p->p_tracep == vp) {
p->p_tracep = NULL;
p->p_traceflag = 0;
vrele(vp);
}
}
sx_sunlock(&allproc_lock);
}
/*
* 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.
*/
static int
ktrcanset(td, targetp)
struct thread *td;
struct proc *targetp;
{
PROC_LOCK_ASSERT(targetp, MA_OWNED);
if (targetp->p_traceflag & KTRFAC_ROOT &&
suser_cred(td->td_ucred, PRISON_ROOT))
return (0);
if (p_candebug(td->td_proc, targetp) != 0)
return (0);
return (1);
}
#endif /* KTRACE */