718cf2ccb9
Mainly focus on files that use BSD 2-Clause license, however the tool I was using misidentified many licenses so this was mostly a manual - error prone - task. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts.
515 lines
12 KiB
C
515 lines
12 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2011, David E. O'Brien.
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* Copyright (c) 2009-2011, Juniper Networks, Inc.
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* Copyright (c) 2015-2016, EMC Corp.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY JUNIPER NETWORKS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL JUNIPER NETWORKS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_compat.h"
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#include <sys/param.h>
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#include <sys/file.h>
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#include <sys/systm.h>
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#include <sys/buf.h>
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#include <sys/capsicum.h>
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#include <sys/condvar.h>
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#include <sys/conf.h>
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#include <sys/fcntl.h>
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#include <sys/ioccom.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/module.h>
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#include <sys/poll.h>
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#include <sys/proc.h>
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#include <sys/sx.h>
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#include <sys/syscall.h>
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#include <sys/sysent.h>
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#include <sys/sysproto.h>
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#include <sys/uio.h>
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#include "filemon.h"
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#if defined(COMPAT_FREEBSD32)
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#include <compat/freebsd32/freebsd32_syscall.h>
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#include <compat/freebsd32/freebsd32_proto.h>
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#include <compat/freebsd32/freebsd32_util.h>
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#endif
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static d_close_t filemon_close;
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static d_ioctl_t filemon_ioctl;
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static d_open_t filemon_open;
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static struct cdevsw filemon_cdevsw = {
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.d_version = D_VERSION,
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.d_close = filemon_close,
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.d_ioctl = filemon_ioctl,
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.d_open = filemon_open,
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.d_name = "filemon",
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};
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MALLOC_DECLARE(M_FILEMON);
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MALLOC_DEFINE(M_FILEMON, "filemon", "File access monitor");
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/*
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* The filemon->lock protects several things currently:
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* - fname1/fname2/msgbufr are pre-allocated and used per syscall
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* for logging and copyins rather than stack variables.
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* - Serializing the filemon's log output.
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* - Preventing inheritance or removal of the filemon into proc.p_filemon.
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*/
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struct filemon {
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struct sx lock; /* Lock for this filemon. */
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struct file *fp; /* Output file pointer. */
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struct ucred *cred; /* Credential of tracer. */
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char fname1[MAXPATHLEN]; /* Temporary filename buffer. */
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char fname2[MAXPATHLEN]; /* Temporary filename buffer. */
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char msgbufr[1024]; /* Output message buffer. */
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int error; /* Log write error, returned on close(2). */
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u_int refcnt; /* Pointer reference count. */
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u_int proccnt; /* Process count. */
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};
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static struct cdev *filemon_dev;
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static void filemon_output(struct filemon *filemon, char *msg, size_t len);
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static __inline struct filemon *
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filemon_acquire(struct filemon *filemon)
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{
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if (filemon != NULL)
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refcount_acquire(&filemon->refcnt);
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return (filemon);
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}
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/*
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* Release a reference and free on the last one.
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*/
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static void
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filemon_release(struct filemon *filemon)
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{
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if (refcount_release(&filemon->refcnt) == 0)
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return;
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/*
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* There are valid cases of releasing while locked, such as in
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* filemon_untrack_processes, but none which are done where there
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* is not at least 1 reference remaining.
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*/
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sx_assert(&filemon->lock, SA_UNLOCKED);
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if (filemon->cred != NULL)
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crfree(filemon->cred);
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sx_destroy(&filemon->lock);
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free(filemon, M_FILEMON);
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}
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/*
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* Acquire the proc's p_filemon reference and lock the filemon.
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* The proc's p_filemon may not match this filemon on return.
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*/
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static struct filemon *
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filemon_proc_get(struct proc *p)
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{
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struct filemon *filemon;
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if (p->p_filemon == NULL)
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return (NULL);
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PROC_LOCK(p);
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filemon = filemon_acquire(p->p_filemon);
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PROC_UNLOCK(p);
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if (filemon == NULL)
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return (NULL);
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/*
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* The p->p_filemon may have changed by now. That case is handled
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* by the exit and fork hooks and filemon_attach_proc specially.
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*/
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sx_xlock(&filemon->lock);
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return (filemon);
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}
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/* Remove and release the filemon on the given process. */
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static void
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filemon_proc_drop(struct proc *p)
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{
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struct filemon *filemon;
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KASSERT(p->p_filemon != NULL, ("%s: proc %p NULL p_filemon",
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__func__, p));
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sx_assert(&p->p_filemon->lock, SA_XLOCKED);
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PROC_LOCK(p);
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filemon = p->p_filemon;
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p->p_filemon = NULL;
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--filemon->proccnt;
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PROC_UNLOCK(p);
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/*
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* This should not be the last reference yet. filemon_release()
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* cannot be called with filemon locked, which the caller expects
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* will stay locked.
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*/
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KASSERT(filemon->refcnt > 1, ("%s: proc %p dropping filemon %p "
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"with last reference", __func__, p, filemon));
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filemon_release(filemon);
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}
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/* Unlock and release the filemon. */
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static __inline void
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filemon_drop(struct filemon *filemon)
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{
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sx_xunlock(&filemon->lock);
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filemon_release(filemon);
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}
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#include "filemon_wrapper.c"
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static void
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filemon_write_header(struct filemon *filemon)
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{
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int len;
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struct timeval now;
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getmicrotime(&now);
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len = snprintf(filemon->msgbufr, sizeof(filemon->msgbufr),
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"# filemon version %d\n# Target pid %d\n# Start %ju.%06ju\nV %d\n",
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FILEMON_VERSION, curproc->p_pid, (uintmax_t)now.tv_sec,
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(uintmax_t)now.tv_usec, FILEMON_VERSION);
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filemon_output(filemon, filemon->msgbufr, len);
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}
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/*
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* Invalidate the passed filemon in all processes.
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*/
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static void
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filemon_untrack_processes(struct filemon *filemon)
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{
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struct proc *p;
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sx_assert(&filemon->lock, SA_XLOCKED);
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/* Avoid allproc loop if there is no need. */
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if (filemon->proccnt == 0)
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return;
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/*
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* Processes in this list won't go away while here since
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* filemon_event_process_exit() will lock on filemon->lock
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* which we hold.
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*/
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sx_slock(&allproc_lock);
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FOREACH_PROC_IN_SYSTEM(p) {
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/*
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* No PROC_LOCK is needed to compare here since it is
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* guaranteed to not change since we have its filemon
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* locked. Everything that changes this p_filemon will
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* be locked on it.
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*/
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if (p->p_filemon == filemon)
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filemon_proc_drop(p);
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}
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sx_sunlock(&allproc_lock);
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/*
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* It's possible some references were acquired but will be
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* dropped shortly as they are restricted from being
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* inherited. There is at least the reference in cdevpriv remaining.
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*/
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KASSERT(filemon->refcnt > 0, ("%s: filemon %p should have "
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"references still.", __func__, filemon));
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KASSERT(filemon->proccnt == 0, ("%s: filemon %p should not have "
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"attached procs still.", __func__, filemon));
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}
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/*
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* Close out the log.
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*/
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static void
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filemon_close_log(struct filemon *filemon)
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{
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struct file *fp;
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struct timeval now;
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size_t len;
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sx_assert(&filemon->lock, SA_XLOCKED);
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if (filemon->fp == NULL)
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return;
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getmicrotime(&now);
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len = snprintf(filemon->msgbufr,
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sizeof(filemon->msgbufr),
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"# Stop %ju.%06ju\n# Bye bye\n",
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(uintmax_t)now.tv_sec, (uintmax_t)now.tv_usec);
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filemon_output(filemon, filemon->msgbufr, len);
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fp = filemon->fp;
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filemon->fp = NULL;
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sx_xunlock(&filemon->lock);
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fdrop(fp, curthread);
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sx_xlock(&filemon->lock);
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}
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/*
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* The devfs file is being closed. Untrace all processes. It is possible
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* filemon_close/close(2) was not called.
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*/
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static void
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filemon_dtr(void *data)
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{
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struct filemon *filemon = data;
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if (filemon == NULL)
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return;
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sx_xlock(&filemon->lock);
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/*
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* Detach the filemon. It cannot be inherited after this.
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*/
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filemon_untrack_processes(filemon);
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filemon_close_log(filemon);
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filemon_drop(filemon);
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}
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/* Attach the filemon to the process. */
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static int
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filemon_attach_proc(struct filemon *filemon, struct proc *p)
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{
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struct filemon *filemon2;
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sx_assert(&filemon->lock, SA_XLOCKED);
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PROC_LOCK_ASSERT(p, MA_OWNED);
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KASSERT((p->p_flag & P_WEXIT) == 0,
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("%s: filemon %p attaching to exiting process %p",
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__func__, filemon, p));
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KASSERT((p->p_flag & P_INEXEC) == 0,
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("%s: filemon %p attaching to execing process %p",
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__func__, filemon, p));
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if (p->p_filemon == filemon)
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return (0);
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/*
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* Don't allow truncating other process traces. It is
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* not really intended to trace procs other than curproc
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* anyhow.
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*/
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if (p->p_filemon != NULL && p != curproc)
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return (EBUSY);
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/*
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* Historic behavior of filemon has been to let a child initiate
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* tracing on itself and cease existing tracing. Bmake
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* .META + .MAKE relies on this. It is only relevant for attaching to
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* curproc.
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*/
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while (p->p_filemon != NULL) {
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PROC_UNLOCK(p);
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sx_xunlock(&filemon->lock);
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while ((filemon2 = filemon_proc_get(p)) != NULL) {
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/* It may have changed. */
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if (p->p_filemon == filemon2)
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filemon_proc_drop(p);
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filemon_drop(filemon2);
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}
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sx_xlock(&filemon->lock);
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PROC_LOCK(p);
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/*
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* It may have been attached to, though unlikely.
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* Try again if needed.
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*/
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}
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KASSERT(p->p_filemon == NULL,
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("%s: proc %p didn't detach filemon %p", __func__, p,
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p->p_filemon));
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p->p_filemon = filemon_acquire(filemon);
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++filemon->proccnt;
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return (0);
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}
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static int
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filemon_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flag __unused,
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struct thread *td)
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{
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int error = 0;
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struct filemon *filemon;
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struct proc *p;
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cap_rights_t rights;
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if ((error = devfs_get_cdevpriv((void **) &filemon)) != 0)
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return (error);
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sx_xlock(&filemon->lock);
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switch (cmd) {
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/* Set the output file descriptor. */
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case FILEMON_SET_FD:
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if (filemon->fp != NULL) {
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error = EEXIST;
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break;
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}
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error = fget_write(td, *(int *)data,
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cap_rights_init(&rights, CAP_PWRITE),
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&filemon->fp);
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if (error == 0)
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/* Write the file header. */
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filemon_write_header(filemon);
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break;
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/* Set the monitored process ID. */
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case FILEMON_SET_PID:
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/* Invalidate any existing processes already set. */
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filemon_untrack_processes(filemon);
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error = pget(*((pid_t *)data),
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PGET_CANDEBUG | PGET_NOTWEXIT | PGET_NOTINEXEC, &p);
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if (error == 0) {
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KASSERT(p->p_filemon != filemon,
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("%s: proc %p didn't untrack filemon %p",
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__func__, p, filemon));
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error = filemon_attach_proc(filemon, p);
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PROC_UNLOCK(p);
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}
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break;
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default:
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error = EINVAL;
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break;
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}
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sx_xunlock(&filemon->lock);
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return (error);
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}
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static int
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filemon_open(struct cdev *dev, int oflags __unused, int devtype __unused,
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struct thread *td)
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{
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int error;
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struct filemon *filemon;
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filemon = malloc(sizeof(*filemon), M_FILEMON,
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M_WAITOK | M_ZERO);
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sx_init(&filemon->lock, "filemon");
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refcount_init(&filemon->refcnt, 1);
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filemon->cred = crhold(td->td_ucred);
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error = devfs_set_cdevpriv(filemon, filemon_dtr);
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if (error != 0)
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filemon_release(filemon);
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return (error);
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}
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/* Called on close of last devfs file handle, before filemon_dtr(). */
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static int
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filemon_close(struct cdev *dev __unused, int flag __unused, int fmt __unused,
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struct thread *td __unused)
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{
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struct filemon *filemon;
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int error;
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if ((error = devfs_get_cdevpriv((void **) &filemon)) != 0)
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return (error);
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sx_xlock(&filemon->lock);
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filemon_close_log(filemon);
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error = filemon->error;
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sx_xunlock(&filemon->lock);
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/*
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* Processes are still being traced but won't log anything
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* now. After this call returns filemon_dtr() is called which
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* will detach processes.
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*/
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return (error);
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}
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static void
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filemon_load(void *dummy __unused)
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{
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/* Install the syscall wrappers. */
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filemon_wrapper_install();
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filemon_dev = make_dev(&filemon_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666,
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"filemon");
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}
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static int
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filemon_unload(void)
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{
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destroy_dev(filemon_dev);
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filemon_wrapper_deinstall();
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return (0);
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}
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static int
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filemon_modevent(module_t mod __unused, int type, void *data)
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{
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int error = 0;
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switch (type) {
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case MOD_LOAD:
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filemon_load(data);
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break;
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case MOD_UNLOAD:
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error = filemon_unload();
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break;
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case MOD_QUIESCE:
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/*
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* The wrapper implementation is unsafe for reliable unload.
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* Require forcing an unload.
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*/
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error = EBUSY;
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break;
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case MOD_SHUTDOWN:
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break;
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default:
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error = EOPNOTSUPP;
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break;
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}
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return (error);
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}
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DEV_MODULE(filemon, filemon_modevent, NULL);
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MODULE_VERSION(filemon, 1);
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