freebsd-dev/sys/kern/kern_ktrace.c
Matthew Dillon 356861db03 Remove the MPSAFE keyword from the parser for syscalls.master.
Instead introduce the [M] prefix to existing keywords.  e.g.
MSTD is the MP SAFE version of STD.  This is prepatory for a
massive Giant lock pushdown.  The old MPSAFE keyword made
syscalls.master too messy.

Begin comments MP-Safe procedures with the comment:
/*
 * MPSAFE
 */
This comments means that the procedure may be called without
Giant held (The procedure itself may still need to obtain
Giant temporarily to do its thing).

sv_prepsyscall() is now MP SAFE and assumed to be MP SAFE
sv_transtrap() is now MP SAFE and assumed to be MP SAFE

ktrsyscall() and ktrsysret() are now MP SAFE (Giant Pushdown)
trapsignal() is now MP SAFE (Giant Pushdown)

Places which used to do the if (mtx_owned(&Giant)) mtx_unlock(&Giant)
test in syscall[2]() in */*/trap.c now do not.  Instead they
explicitly unlock Giant if they previously obtained it, and then
assert that it is no longer held to catch broken system calls.

Rebuild syscall tables.
2001-08-30 18:50:57 +00:00

551 lines
12 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 __P((int type));
static void ktrwrite __P((struct vnode *, struct ktr_header *, struct uio *));
static int ktrcanset __P((struct proc *,struct proc *));
static int ktrsetchildren __P((struct proc *,struct proc *,int,int,struct vnode *));
static int ktrops __P((struct proc *,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 */
p->p_traceflag |= KTRFAC_ACTIVE;
kth = ktrgetheader(KTR_NAMEI);
kth->ktr_len = strlen(path);
kth->ktr_buffer = path;
ktrwrite(vp, kth, NULL);
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;
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);
FREE(kth, M_KTRACE);
p->p_traceflag &= ~KTRFAC_ACTIVE;
}
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 */
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);
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 */
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);
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(curp, uap)
struct proc *curp;
register struct ktrace_args *uap;
{
#ifdef KTRACE
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, curp);
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, curp);
if (vp->v_type != VREG) {
(void) vn_close(vp, FREAD|FWRITE, curp->p_ucred, curp);
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) {
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;
}
}
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
*/
pg = pgfind(-uap->pid);
if (pg == NULL) {
error = ESRCH;
goto done;
}
LIST_FOREACH(p, &pg->pg_members, p_pglist)
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;
}
PROC_UNLOCK(p);
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);
curp->p_traceflag &= ~KTRFAC_ACTIVE;
return (error);
#else
return ENOSYS;
#endif
}
/*
* utrace system call
*/
/* ARGSUSED */
int
utrace(curp, uap)
struct proc *curp;
register struct utrace_args *uap;
{
#ifdef KTRACE
struct ktr_header *kth;
struct proc *p = curproc; /* XXX */
register caddr_t cp;
if (!KTRPOINT(p, KTR_USER))
return (0);
if (uap->len > KTR_USER_MAXLEN)
return (EINVAL);
p->p_traceflag |= KTRFAC_ACTIVE;
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(p->p_tracep, kth, NULL);
}
FREE(kth, M_KTRACE);
FREE(cp, M_KTRACE);
p->p_traceflag &= ~KTRFAC_ACTIVE;
return (0);
#else
return (ENOSYS);
#endif
}
#ifdef KTRACE
static int
ktrops(curp, p, ops, facs, vp)
struct proc *p, *curp;
int ops, facs;
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);
}
static int
ktrsetchildren(curp, top, ops, facs, vp)
struct proc *curp, *top;
int ops, facs;
struct vnode *vp;
{
register struct proc *p;
register int ret = 0;
p = top;
sx_slock(&proctree_lock);
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 (!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 proc *p = curproc; /* 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_procp = curproc;
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, p);
(void)VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, p->p_ucred);
if (error == 0 && uio != NULL) {
(void)VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
error = VOP_WRITE(vp, uio, IO_UNIT | IO_APPEND, p->p_ucred);
}
VOP_UNLOCK(vp, 0, p);
vn_finished_write(mp);
if (!error)
return;
/*
* If error encountered, give up tracing on this vnode.
*/
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(callp, targetp)
struct proc *callp, *targetp;
{
if (targetp->p_traceflag & KTRFAC_ROOT &&
suser_xxx(NULL, callp, PRISON_ROOT))
return (0);
if (p_candebug(callp, targetp) != 0)
return (0);
return (1);
}
#endif /* KTRACE */