0ec5ac100c
- remove return statements from void function [1] - include missing header - use O_CLOEXEC instead of separate fcntl() calls PR: docs/179459 [1] MFC after: 1 week
175 lines
4.3 KiB
Groff
175 lines
4.3 KiB
Groff
.\" Copyright (c) 2012
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.\" David E. O'Brien <obrien@FreeBSD.org>. 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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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgment:
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.\" This product includes software developed by David E. O'Brien and
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.\" contributors.
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.\" 4. Neither the name of the author nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 MERCHANT ABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR 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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.\" $FreeBSD$
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.\"
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.Dd June 14, 2013
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.Dt FILEMON 4
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.Os
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.Sh NAME
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.Nm filemon
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.Nd the filemon device
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.Sh SYNOPSIS
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.In dev/filemon/filemon.h
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.Sh DESCRIPTION
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The
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.Nm
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device allows a process to collect file operations data of its children.
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The device
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.Pa /dev/filemon
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responds to two
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.Xr ioctl 2
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calls.
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.Pp
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System calls are denoted using the following single letters:
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.Pp
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.Bl -tag -width indent -compact
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.It Ql C
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.Xr chdir 2
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.It Ql D
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.Xr unlink 2
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.It Ql E
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.Xr exec 2
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.It Ql F
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.Xr fork 2 ,
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.Xr vfork 2
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.It Ql L
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.Xr link 2 ,
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.Xr linkat 2 ,
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.Xr symlink 2 ,
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.Xr symlinkat 2
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.It Ql M
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.Xr rename 2
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.It Ql R
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.Xr open 2
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for read
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.It Ql S
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.Xr stat 2
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.It Ql W
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.Xr open 2
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for write
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.It Ql X
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.Xr _exit 2
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.El
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.Pp
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Note that
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.Ql R
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following
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.Ql W
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records can represent a single
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.Xr open 2
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for R/W,
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or two separate
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.Xr open 2
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calls, one for
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.Ql R
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and one for
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.Ql W .
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Note that only successful system calls are captured.
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.Sh IOCTLS
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User mode programs communicate with the
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.Nm
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driver through a number of ioctls which are described below.
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Each takes a single argument.
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.Bl -tag -width ".Dv FILEMON_SET_PID"
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.It Dv FILEMON_SET_FD
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Write the internal tracing buffer to the supplied open file descriptor.
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.It Dv FILEMON_SET_PID
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Child process ID to trace.
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.El
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.Sh RETURN VALUES
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.\" .Rv -std ioctl
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The
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.Fn ioctl
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function returns the value 0 if successful;
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otherwise the value \-1 is returned and the global variable
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.Va errno
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is set to indicate the error.
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.Sh FILES
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.Bl -tag -width ".Pa /dev/filemon"
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.It Pa /dev/filemon
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.El
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.Sh EXAMPLES
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.Bd -literal
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/wait.h>
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#include <sys/ioctl.h>
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#include <dev/filemon/filemon.h>
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#include <fcntl.h>
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#include <err.h>
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#include <unistd.h>
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static void
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open_filemon(void)
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{
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pid_t child;
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int fm_fd, fm_log;
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if ((fm_fd = open("/dev/filemon", O_RDWR | O_CLOEXEC)) == -1)
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err(1, "open(\e"/dev/filemon\e", O_RDWR)");
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if ((fm_log = open("filemon.out",
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O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC, DEFFILEMODE)) == -1)
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err(1, "open(filemon.out)");
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if (ioctl(fm_fd, FILEMON_SET_FD, &fm_log) == -1)
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err(1, "Cannot set filemon log file descriptor");
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if ((child = fork()) == 0) {
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child = getpid();
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if (ioctl(fm_fd, FILEMON_SET_PID, &child) == -1)
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err(1, "Cannot set filemon PID");
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/* Do something here. */
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} else {
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wait(&child);
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close(fm_fd);
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}
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}
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.Ed
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.Pp
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Creates a file named
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.Pa filemon.out
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and configures the
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.Nm
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device to write the
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.Nm
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buffer contents to it.
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.Sh SEE ALSO
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.Xr dtrace 1 ,
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.Xr ktrace 1 ,
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.Xr truss 1 ,
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.Xr ioctl 2
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.Sh HISTORY
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A
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.Nm
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device appeared in
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.Fx 9.1 .
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