1.\" Copyright (c) 2012 2.\" David E. O'Brien <obrien@FreeBSD.org>. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgment: 14.\" This product includes software developed by David E. O'Brien and 15.\" contributors. 16.\" 4. Neither the name of the author nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANT ABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" $FreeBSD$ 33.\" 34.Dd May 30, 2012 35.Dt FILEMON 4 36.Os 37.Sh NAME 38.Nm filemon 39.Nd the filemon device 40.Sh SYNOPSIS 41.In dev/filemon/filemon.h 42.Sh DESCRIPTION 43The 44.Nm 45device allows a process to collect file operations data of its children. 46The device 47.Pa /dev/filemon 48responds to two 49.Xr ioctl 2 50calls. 51.Pp 52System calls are denoted using the following single letters: 53.Pp 54.Bl -tag -width indent -compact 55.It Ql C 56.Xr chdir 2 57.It Ql D 58.Xr unlink 2 59.It Ql E 60.Xr exec 2 61.It Ql F 62.Xr fork 2 , 63.Xr vfork 2 64.It Ql L 65.Xr link 2 , 66.Xr linkat 2 , 67.Xr symlink 2 , 68.Xr symlinkat 2 69.It Ql M 70.Xr rename 2 71.It Ql R 72.Xr open 2 73for read 74.It Ql S 75.Xr stat 2 76.It Ql W 77.Xr open 2 78for write 79.It Ql X 80.Xr _exit 2 81.El 82.Pp 83Note that 84.Ql R 85following 86.Ql W 87records can represent a single 88.Xr open 2 89for R/W, 90or two separate 91.Xr open 2 92calls, one for 93.Ql R 94and one for 95.Ql W . 96Note that only successful system calls are captured. 97.Sh IOCTLS 98User mode programs communicate with the 99.Nm 100driver through a number of ioctls which are described below. 101Each takes a single argument. 102.Bl -tag -width ".Dv FILEMON_SET_PID" 103.It Dv FILEMON_SET_FD 104Write the internal tracing buffer to the supplied open file descriptor. 105.It Dv FILEMON_SET_PID 106Child process ID to trace. 107.El 108.Sh RETURN VALUES 109.\" .Rv -std ioctl 110The 111.Fn ioctl 112function returns the value 0 if successful; 113otherwise the value \-1 is returned and the global variable 114.Va errno 115is set to indicate the error. 116.Sh FILES 117.Bl -tag -width ".Pa /dev/filemon" 118.It Pa /dev/filemon 119.El 120.Sh EXAMPLES 121.Bd -literal 122#include <sys/types.h> 123#include <sys/stat.h> 124#include <sys/wait.h> 125#include <sys/ioctl.h> 126#include <dev/filemon/filemon.h> 127#include <fcntl.h> 128#include <err.h> 129 130static void 131open_filemon(void) 132{ 133 pid_t child; 134 int fm_fd, fm_log; 135 136 if ((fm_fd = open("/dev/filemon", O_RDWR)) == -1) 137 err(1, "open(\e"/dev/filemon\e", O_RDWR)"); 138 if ((fm_log = open("filemon.out", 139 O_CREAT | O_WRONLY | O_TRUNC, DEFFILEMODE)) == -1) 140 err(1, "open(filemon.out)"); 141 142 if (ioctl(fm_fd, FILEMON_SET_FD, &fm_log) == -1) 143 err(1, "Cannot set filemon log file descriptor"); 144 /* Set up these two fd's to close on exec. */ 145 (void)fcntl(fm_fd, F_SETFD, FD_CLOEXEC); 146 (void)fcntl(fm_log, F_SETFD, FD_CLOEXEC); 147 148 if ((child = fork()) == 0) { 149 child = getpid(); 150 if (ioctl(fm_fd, FILEMON_SET_PID, &child) == -1) 151 err(1, "Cannot set filemon PID"); 152 /* Do something here. */ 153 return 0; 154 } else { 155 wait(&child); 156 close(fm_fd); 157 } 158 return 0; 159} 160.Ed 161.Pp 162Creates a file named 163.Pa filemon.out 164and configures the 165.Nm 166device to write the 167.Nm 168buffer contents to it. 169.Sh SEE ALSO 170.Xr dtrace 1 , 171.Xr ktrace 1 , 172.Xr truss 1 , 173.Xr ioctl 2 174.Sh HISTORY 175A 176.Nm 177device appeared in 178.Fx 9.1 . 179