NetBSD/sys/kern/kern_ktrace.c

680 lines
15 KiB
C

/* $NetBSD: kern_ktrace.c,v 1.39 2000/04/19 19:14:17 thorpej Exp $ */
/*
* 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 8.5 (Berkeley) 5/14/95
*/
#include "opt_ktrace.h"
#ifdef KTRACE
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/ktrace.h>
#include <sys/malloc.h>
#include <sys/syslog.h>
#include <sys/filedesc.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
void ktrinitheader __P((struct ktr_header *, struct proc *, int));
int ktrops __P((struct proc *, struct proc *, int, int, void *));
int ktrsetchildren __P((struct proc *, struct proc *, int, int, void *));
int ktrwrite __P((struct proc *, void *, struct ktr_header *));
int ktrcanset __P((struct proc *, struct proc *));
void
ktrderef(p)
struct proc *p;
{
if (p->p_tracep == NULL)
return;
if (p->p_traceflag & KTRFAC_FD) {
struct file *fp = p->p_tracep;
FILE_USE(fp);
closef(fp, NULL);
} else {
struct vnode *vp = p->p_tracep;
vrele(vp);
}
p->p_tracep = NULL;
p->p_traceflag = 0;
}
void
ktradref(p)
struct proc *p;
{
if (p->p_traceflag & KTRFAC_FD) {
struct file *fp = p->p_tracep;
fp->f_count++;
} else {
struct vnode *vp = p->p_tracep;
VREF(vp);
}
}
void
ktrinitheader(kth, p, type)
struct ktr_header *kth;
struct proc *p;
int type;
{
memset(kth, 0, sizeof(*kth));
kth->ktr_type = type;
microtime(&kth->ktr_time);
kth->ktr_pid = p->p_pid;
memcpy(kth->ktr_comm, p->p_comm, MAXCOMLEN);
}
void
ktrsyscall(v, code, argsize, args)
void *v;
register_t code;
size_t argsize;
register_t args[];
{
struct ktr_header kth;
struct ktr_syscall *ktp;
struct proc *p = curproc; /* XXX */
register_t *argp;
size_t len = sizeof(struct ktr_syscall) + argsize;
int i;
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_SYSCALL);
ktp = malloc(len, M_TEMP, M_WAITOK);
ktp->ktr_code = code;
ktp->ktr_argsize = argsize;
argp = (register_t *)((char *)ktp + sizeof(struct ktr_syscall));
for (i = 0; i < (argsize / sizeof(*argp)); i++)
*argp++ = args[i];
kth.ktr_buf = (caddr_t)ktp;
kth.ktr_len = len;
(void) ktrwrite(p, v, &kth);
free(ktp, M_TEMP);
p->p_traceflag &= ~KTRFAC_ACTIVE;
}
void
ktrsysret(v, code, error, retval)
void *v;
register_t code;
int error;
register_t retval;
{
struct ktr_header kth;
struct ktr_sysret ktp;
struct proc *p = curproc; /* XXX */
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_SYSRET);
ktp.ktr_code = code;
ktp.ktr_eosys = 0; /* XXX unused */
ktp.ktr_error = error;
ktp.ktr_retval = retval; /* what about val2 ? */
kth.ktr_buf = (caddr_t)&ktp;
kth.ktr_len = sizeof(struct ktr_sysret);
(void) ktrwrite(p, v, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
}
void
ktrnamei(v, path)
void *v;
char *path;
{
struct ktr_header kth;
struct proc *p = curproc; /* XXX */
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_NAMEI);
kth.ktr_len = strlen(path);
kth.ktr_buf = path;
(void) ktrwrite(p, v, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
}
void
ktremul(v, p, emul)
void *v;
struct proc *p;
char *emul;
{
struct ktr_header kth;
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_EMUL);
kth.ktr_len = strlen(emul);
kth.ktr_buf = emul;
(void) ktrwrite(p, v, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
}
void
ktrgenio(v, fd, rw, iov, len, error)
void *v;
int fd;
enum uio_rw rw;
struct iovec *iov;
int len, error;
{
struct ktr_header kth;
struct ktr_genio *ktp;
caddr_t cp;
int resid = len, cnt;
struct proc *p = curproc; /* XXX */
int buflen;
if (error)
return;
p->p_traceflag |= KTRFAC_ACTIVE;
buflen = min(PAGE_SIZE, len + sizeof(struct ktr_genio));
ktrinitheader(&kth, p, KTR_GENIO);
ktp = malloc(buflen, M_TEMP, M_WAITOK);
ktp->ktr_fd = fd;
ktp->ktr_rw = rw;
kth.ktr_buf = (caddr_t)ktp;
cp = (caddr_t)((char *)ktp + sizeof(struct ktr_genio));
buflen -= sizeof(struct ktr_genio);
while (resid > 0) {
if (p->p_schedflags & PSCHED_SHOULDYIELD)
preempt(NULL);
cnt = min(iov->iov_len, buflen);
if (cnt > resid)
cnt = resid;
if (copyin(iov->iov_base, cp, cnt))
break;
kth.ktr_len = cnt + sizeof(struct ktr_genio);
if (ktrwrite(p, v, &kth) != 0)
break;
iov->iov_base = (caddr_t)iov->iov_base + cnt;
iov->iov_len -= cnt;
if (iov->iov_len == 0)
iov++;
resid -= cnt;
}
free(ktp, M_TEMP);
p->p_traceflag &= ~KTRFAC_ACTIVE;
}
void
ktrpsig(v, sig, action, mask, code)
void *v;
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;
ktrinitheader(&kth, p, KTR_PSIG);
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);
(void) ktrwrite(p, v, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
}
void
ktrcsw(v, out, user)
void *v;
int out, user;
{
struct ktr_header kth;
struct ktr_csw kc;
struct proc *p = curproc; /* XXX */
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_CSW);
kc.out = out;
kc.user = user;
kth.ktr_buf = (caddr_t)&kc;
kth.ktr_len = sizeof(struct ktr_csw);
(void) ktrwrite(p, v, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
}
/* Interface and common routines */
/*
* ktrace system call
*/
/* ARGSUSED */
int
sys_fktrace(curp, v, retval)
struct proc *curp;
void *v;
register_t *retval;
{
struct sys_fktrace_args /* {
syscallarg(int) fd;
syscallarg(int) ops;
syscallarg(int) facs;
syscallarg(int) pid;
} */ *uap = v;
struct file *fp = NULL;
struct proc *p;
struct filedesc *fdp = curp->p_fd;
struct pgrp *pg;
int facs;
int ops;
int descend;
int ret = 0;
int error = 0;
if (((u_int)SCARG(uap, fd)) >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[SCARG(uap, fd)]) == NULL ||
(fp->f_flag & FWRITE) == 0)
return (EBADF);
ops = KTROP(SCARG(uap, ops)) | KTRFLAG_FD;
descend = SCARG(uap, ops) & KTRFLAG_DESCEND;
facs = SCARG(uap, facs) & ~((unsigned) KTRFAC_ROOT);
curp->p_traceflag |= KTRFAC_ACTIVE;
/*
* Clear all uses of the tracefile
*/
if (KTROP(ops) == KTROP_CLEARFILE) {
proclist_lock_read();
for (p = LIST_FIRST(&allproc); p != NULL;
p = LIST_NEXT(p, p_list)) {
if (p->p_tracep == fp) {
if (ktrcanset(curp, p))
ktrderef(p);
else
error = EPERM;
}
}
proclist_unlock_read();
goto done;
}
/*
* need something to (un)trace (XXX - why is this here?)
*/
if (!facs) {
error = EINVAL;
goto done;
}
/*
* do it
*/
if (SCARG(uap, pid) < 0) {
/*
* by process group
*/
pg = pgfind(-SCARG(uap, pid));
if (pg == NULL) {
error = ESRCH;
goto done;
}
for (p = LIST_FIRST(&pg->pg_members); p != NULL;
p = LIST_NEXT(p, p_pglist)) {
if (descend)
ret |= ktrsetchildren(curp, p, ops, facs, fp);
else
ret |= ktrops(curp, p, ops, facs, fp);
}
} else {
/*
* by pid
*/
p = pfind(SCARG(uap, pid));
if (p == NULL) {
error = ESRCH;
goto done;
}
if (descend)
ret |= ktrsetchildren(curp, p, ops, facs, fp);
else
ret |= ktrops(curp, p, ops, facs, fp);
}
if (!ret)
error = EPERM;
done:
curp->p_traceflag &= ~KTRFAC_ACTIVE;
return (error);
}
/*
* ktrace system call
*/
/* ARGSUSED */
int
sys_ktrace(curp, v, retval)
struct proc *curp;
void *v;
register_t *retval;
{
struct sys_ktrace_args /* {
syscallarg(const char *) fname;
syscallarg(int) ops;
syscallarg(int) facs;
syscallarg(int) pid;
} */ *uap = v;
struct vnode *vp = NULL;
struct proc *p;
struct pgrp *pg;
int facs = SCARG(uap, facs) & ~((unsigned) KTRFAC_ROOT);
int ops = KTROP(SCARG(uap, ops));
int descend = SCARG(uap, ops) & KTRFLAG_DESCEND;
int ret = 0;
int error = 0;
struct nameidata nd;
curp->p_traceflag |= KTRFAC_ACTIVE;
if (ops != KTROP_CLEAR) {
/*
* an operation which requires a file argument.
*/
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, fname),
curp);
if ((error = vn_open(&nd, FREAD|FWRITE, 0)) != 0) {
curp->p_traceflag &= ~KTRFAC_ACTIVE;
return (error);
}
vp = nd.ni_vp;
VOP_UNLOCK(vp, 0);
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 (KTROP(ops) == KTROP_CLEARFILE) {
proclist_lock_read();
for (p = LIST_FIRST(&allproc); p != NULL;
p = LIST_NEXT(p, p_list)) {
if (p->p_tracep == vp &&
!ktrops(curp, p, KTROP_CLEAR, ~0, vp))
error = EPERM;
}
proclist_unlock_read();
goto done;
}
/*
* need something to (un)trace (XXX - why is this here?)
*/
if (!facs) {
error = EINVAL;
goto done;
}
/*
* do it
*/
if (SCARG(uap, pid) < 0) {
/*
* by process group
*/
pg = pgfind(-SCARG(uap, pid));
if (pg == NULL) {
error = ESRCH;
goto done;
}
for (p = LIST_FIRST(&pg->pg_members); p != NULL;
p = LIST_NEXT(p, p_pglist)) {
if (descend)
ret |= ktrsetchildren(curp, p, ops, facs, vp);
else
ret |= ktrops(curp, p, ops, facs, vp);
}
} else {
/*
* by pid
*/
p = pfind(SCARG(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);
curp->p_traceflag &= ~KTRFAC_ACTIVE;
return (error);
}
int
ktrops(curp, p, ops, facs, v)
struct proc *p, *curp;
int ops, facs;
void *v;
{
if (!ktrcanset(curp, p))
return (0);
if (KTROP(ops) == KTROP_SET) {
if (p->p_tracep != v) {
/*
* if trace file already in use, relinquish
*/
ktrderef(p);
if (ops & KTRFLAG_FD)
p->p_traceflag = KTRFAC_FD;
p->p_tracep = v;
ktradref(p);
}
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 */
ktrderef(p);
}
}
/*
* Emit an emulation record, every time there is a ktrace
* change/attach request.
*/
if (KTRPOINT(p, KTR_EMUL))
ktremul(p->p_tracep, p, p->p_emul->e_name);
return (1);
}
int
ktrsetchildren(curp, top, ops, facs, v)
struct proc *curp, *top;
int ops, facs;
void *v;
{
struct proc *p;
int ret = 0;
p = top;
for (;;) {
ret |= ktrops(curp, p, ops, facs, v);
/*
* 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_FIRST(&p->p_children) != NULL)
p = LIST_FIRST(&p->p_children);
else for (;;) {
if (p == top)
return (ret);
if (LIST_NEXT(p, p_sibling) != NULL) {
p = LIST_NEXT(p, p_sibling);
break;
}
p = p->p_pptr;
}
}
/*NOTREACHED*/
}
int
ktrwrite(p, v, kth)
struct proc *p;
void *v;
struct ktr_header *kth;
{
struct uio auio;
struct iovec aiov[2];
int error;
if (v == NULL)
return (0);
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;
}
if (p->p_traceflag & KTRFAC_FD) {
struct file *fp = v;
FILE_USE(fp);
error = (*fp->f_ops->fo_write)(fp, &fp->f_offset, &auio,
fp->f_cred, FOF_UPDATE_OFFSET);
FILE_UNUSE(fp, NULL);
}
else {
struct vnode *vp = v;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
error = VOP_WRITE(vp, &auio, IO_UNIT|IO_APPEND, p->p_ucred);
VOP_UNLOCK(vp, 0);
}
if (error == 0)
return (0);
/*
* If error encountered, give up tracing on this vnode. Don't report
* EPIPE as this can easily happen with fktrace()/ktruss.
*/
if (error != EPIPE)
log(LOG_NOTICE,
"ktrace write failed, errno %d, tracing stopped\n",
error);
proclist_lock_read();
for (p = LIST_FIRST(&allproc); p != NULL; p = LIST_NEXT(p, p_list)) {
if (p->p_tracep == v)
ktrderef(p);
}
proclist_unlock_read();
return (error);
}
/*
* 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.
*/
int
ktrcanset(callp, targetp)
struct proc *callp, *targetp;
{
struct pcred *caller = callp->p_cred;
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