NetBSD/sys/kern/kern_ktrace.c

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/* $NetBSD: kern_ktrace.c,v 1.46 2000/05/31 05:02:32 thorpej Exp $ */
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/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
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*
* 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.
*
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* @(#)kern_ktrace.c 8.5 (Berkeley) 5/14/95
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*/
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#include "opt_ktrace.h"
#ifdef KTRACE
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#include <sys/param.h>
#include <sys/systm.h>
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#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/ioctl.h>
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#include <sys/mount.h>
#include <sys/syscallargs.h>
int ktrace_common __P((struct proc *, int, int, int, struct file *));
void ktrinitheader __P((struct ktr_header *, struct proc *, int));
int ktrops __P((struct proc *, struct proc *, int, int, struct file *));
int ktrsetchildren __P((struct proc *, struct proc *, int, int,
struct file *));
int ktrwrite __P((struct proc *, struct ktr_header *));
int ktrcanset __P((struct proc *, struct proc *));
int ktrsamefile __P((struct file *, struct file *));
/*
* "deep" compare of two files for the purposes of clearing a trace.
* Returns true if they're the same open file, or if they point at the
* same underlying vnode/socket.
*/
int
ktrsamefile (f1, f2)
struct file *f1, *f2;
{
return ((f1 == f2) ||
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((f1 != NULL) && (f2 != NULL) &&
(f1->f_type == f2->f_type) &&
(f1->f_data == f2->f_data)));
}
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void
ktrderef(p)
struct proc *p;
{
struct file *fp = p->p_tracep;
p->p_traceflag = 0;
if (fp == NULL)
return;
FILE_USE(fp);
closef(fp, NULL);
p->p_tracep = NULL;
}
void
ktradref(p)
struct proc *p;
{
struct file *fp = p->p_tracep;
fp->f_count++;
}
void
ktrinitheader(kth, p, type)
struct ktr_header *kth;
struct proc *p;
int type;
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{
memset(kth, 0, sizeof(*kth));
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kth->ktr_type = type;
microtime(&kth->ktr_time);
kth->ktr_pid = p->p_pid;
memcpy(kth->ktr_comm, p->p_comm, MAXCOMLEN);
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}
void
ktrsyscall(p, code, argsize, args)
struct proc *p;
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register_t code;
size_t argsize;
register_t args[];
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{
struct ktr_header kth;
struct ktr_syscall *ktp;
register_t *argp;
size_t len = sizeof(struct ktr_syscall) + argsize;
int i;
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p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_SYSCALL);
ktp = malloc(len, M_TEMP, M_WAITOK);
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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++)
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*argp++ = args[i];
kth.ktr_buf = (caddr_t)ktp;
kth.ktr_len = len;
(void) ktrwrite(p, &kth);
free(ktp, M_TEMP);
p->p_traceflag &= ~KTRFAC_ACTIVE;
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}
void
ktrsysret(p, code, error, retval)
struct proc *p;
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register_t code;
int error;
register_t retval;
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{
struct ktr_header kth;
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struct ktr_sysret ktp;
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_SYSRET);
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ktp.ktr_code = code;
ktp.ktr_eosys = 0; /* XXX unused */
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ktp.ktr_error = error;
ktp.ktr_retval = retval; /* what about val2 ? */
kth.ktr_buf = (caddr_t)&ktp;
kth.ktr_len = sizeof(struct ktr_sysret);
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(void) ktrwrite(p, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
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}
void
ktrnamei(p, path)
struct proc *p;
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char *path;
{
struct ktr_header kth;
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p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_NAMEI);
kth.ktr_len = strlen(path);
kth.ktr_buf = path;
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(void) ktrwrite(p, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
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}
void
ktremul(p)
struct proc *p;
{
struct ktr_header kth;
char *emul = p->p_emul->e_name;
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_EMUL);
kth.ktr_len = strlen(emul);
kth.ktr_buf = emul;
(void) ktrwrite(p, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
}
void
ktrgenio(p, fd, rw, iov, len, error)
struct proc *p;
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int fd;
enum uio_rw rw;
struct iovec *iov;
int len, error;
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{
struct ktr_header kth;
struct ktr_genio *ktp;
caddr_t cp;
int resid = len, cnt;
int buflen;
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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);
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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);
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while (resid > 0) {
KDASSERT(p->p_cpu != NULL);
KDASSERT(p->p_cpu == curcpu());
if (p->p_cpu->ci_schedstate.spc_flags & SPCF_SHOULDYIELD)
preempt(NULL);
cnt = min(iov->iov_len, buflen);
if (cnt > resid)
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cnt = resid;
if (copyin(iov->iov_base, cp, cnt))
break;
kth.ktr_len = cnt + sizeof(struct ktr_genio);
if (__predict_false(ktrwrite(p, &kth) != 0))
break;
iov->iov_base = (caddr_t)iov->iov_base + cnt;
iov->iov_len -= cnt;
if (iov->iov_len == 0)
iov++;
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resid -= cnt;
}
free(ktp, M_TEMP);
p->p_traceflag &= ~KTRFAC_ACTIVE;
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}
void
ktrpsig(p, sig, action, mask, code)
struct proc *p;
int sig;
sig_t action;
sigset_t *mask;
int code;
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{
struct ktr_header kth;
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struct ktr_psig kp;
p->p_traceflag |= KTRFAC_ACTIVE;
ktrinitheader(&kth, p, KTR_PSIG);
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kp.signo = (char)sig;
kp.action = action;
kp.mask = *mask;
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kp.code = code;
kth.ktr_buf = (caddr_t)&kp;
kth.ktr_len = sizeof(struct ktr_psig);
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(void) ktrwrite(p, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
}
void
ktrcsw(p, out, user)
struct proc *p;
int out, user;
{
struct ktr_header kth;
struct ktr_csw kc;
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, &kth);
p->p_traceflag &= ~KTRFAC_ACTIVE;
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}
/* Interface and common routines */
int
ktrace_common (curp, ops, facs, pid, fp)
struct proc *curp;
int ops, facs, pid;
struct file *fp;
{
int ret = 0;
int error = 0;
int one = 1;
int descend;
struct proc *p;
struct pgrp *pg;
curp->p_traceflag |= KTRFAC_ACTIVE;
descend = ops & KTRFLAG_DESCEND;
facs = facs & ~((unsigned) KTRFAC_ROOT);
/*
* 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 (ktrsamefile(p->p_tracep, fp)) {
if (ktrcanset(curp, p))
ktrderef(p);
else
error = EPERM;
}
}
proclist_unlock_read();
goto done;
}
/*
* Mark fp non-blocking, to avoid problems from possible deadlocks.
*/
if (fp != NULL) {
fp->f_flag |= FNONBLOCK;
(*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&one, curp);
}
/*
* need something to (un)trace (XXX - why is this here?)
*/
if (!facs) {
error = EINVAL;
goto done;
}
/*
* do it
*/
if (pid < 0) {
/*
* by process group
*/
pg = pgfind(-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(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_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 filedesc *fdp = curp->p_fd;
if (((u_int)SCARG(uap, fd)) >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[SCARG(uap, fd)]) == NULL ||
(fp->f_flag & FWRITE) == 0)
return (EBADF);
return ktrace_common(curp, SCARG(uap, ops),
SCARG(uap, facs), SCARG(uap, pid), fp);
}
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/*
* ktrace system call
*/
/* ARGSUSED */
int
sys_ktrace(curp, v, retval)
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struct proc *curp;
void *v;
register_t *retval;
{
struct sys_ktrace_args /* {
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syscallarg(const char *) fname;
syscallarg(int) ops;
syscallarg(int) facs;
syscallarg(int) pid;
} */ *uap = v;
struct vnode *vp = NULL;
struct file *fp = NULL;
int fd;
int ops = SCARG(uap, ops);
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int error = 0;
struct nameidata nd;
ops = KTROP(ops) | (ops & KTRFLAG_DESCEND);
curp->p_traceflag |= KTRFAC_ACTIVE;
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if (ops != KTROP_CLEAR) {
/*
* an operation which requires a file argument.
*/
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, fname),
curp);
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if ((error = vn_open(&nd, FREAD|FWRITE, 0)) != 0) {
curp->p_traceflag &= ~KTRFAC_ACTIVE;
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return (error);
}
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vp = nd.ni_vp;
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VOP_UNLOCK(vp, 0);
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if (vp->v_type != VREG) {
(void) vn_close(vp, FREAD|FWRITE, curp->p_ucred, curp);
curp->p_traceflag &= ~KTRFAC_ACTIVE;
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return (EACCES);
}
/*
* XXX This uses up a file descriptor slot in the
* tracing process for the duration of this syscall.
* This is not expected to be a problem. If
* falloc(NULL, ...) DTRT we could skip that part, but
* that would require changing its interface to allow
* the caller to pass in a ucred..
*
* This will FILE_USE the fp it returns, if any.
* Keep it in use until we return.
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*/
if ((error = falloc(curp, &fp, &fd)) != 0)
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goto done;
fp->f_flag = FWRITE|FAPPEND;
fp->f_type = DTYPE_VNODE;
fp->f_ops = &vnops;
fp->f_data = (caddr_t)vp;
vp = NULL;
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}
error = ktrace_common(curp, SCARG(uap, ops), SCARG(uap, facs),
SCARG(uap, pid), fp);
done:
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if (vp != NULL)
(void) vn_close(vp, FWRITE, curp->p_ucred, curp);
if (fp != NULL) {
FILE_UNUSE(fp, curp); /* release file */
fdrelease(curp, fd); /* release fd table slot */
}
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return (error);
}
int
ktrops(curp, p, ops, facs, fp)
struct proc *p, *curp;
int ops, facs;
struct file *fp;
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{
if (!ktrcanset(curp, p))
return (0);
if (KTROP(ops) == KTROP_SET) {
if (p->p_tracep != fp) {
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/*
* if trace file already in use, relinquish
*/
ktrderef(p);
p->p_tracep = fp;
ktradref(p);
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}
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);
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}
}
/*
* Emit an emulation record, every time there is a ktrace
* change/attach request.
*/
if (KTRPOINT(p, KTR_EMUL))
ktremul(p);
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return (1);
}
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int
ktrsetchildren(curp, top, ops, facs, fp)
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struct proc *curp, *top;
int ops, facs;
struct file *fp;
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{
struct proc *p;
int ret = 0;
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p = top;
for (;;) {
ret |= ktrops(curp, p, ops, facs, fp);
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/*
* 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);
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else for (;;) {
if (p == top)
return (ret);
if (LIST_NEXT(p, p_sibling) != NULL) {
p = LIST_NEXT(p, p_sibling);
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break;
}
p = p->p_pptr;
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}
}
/*NOTREACHED*/
}
int
ktrwrite(p, kth)
struct proc *p;
struct ktr_header *kth;
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{
struct uio auio;
struct iovec aiov[2];
int error, tries;
struct file *fp = p->p_tracep;
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if (fp == NULL)
return 0;
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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;
}
FILE_USE(fp);
tries = 0;
do {
error = (*fp->f_ops->fo_write)(fp, &fp->f_offset, &auio,
fp->f_cred, FOF_UPDATE_OFFSET);
tries++;
if (error == EWOULDBLOCK)
yield();
} while ((error == EWOULDBLOCK) && (tries < 3));
FILE_UNUSE(fp, NULL);
if (__predict_true(error == 0))
return (0);
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/*
* If error encountered, give up tracing on this vnode. Don't report
* EPIPE as this can easily happen with fktrace()/ktruss.
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*/
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 (ktrsamefile(p->p_tracep, fp))
ktrderef(p);
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}
proclist_unlock_read();
return (error);
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}
/*
* 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.
*/
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int
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ktrcanset(callp, targetp)
struct proc *callp, *targetp;
{
struct pcred *caller = callp->p_cred;
struct pcred *target = targetp->p_cred;
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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