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 acknowledgement: 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 MERCHANTABILITY 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 seperate 91.Xr open 2 92calls, one for 93.Ql R 94and one for 95.Ql W . 96.Sh IOCTLS 97User mode programs communicate with the 98.Nm 99driver through a number of ioctls which are described below. 100Each takes a single argument. 101.Bl -tag -width ".Dv FILEMON_SET_PID" 102.It Dv FILEMON_SET_FD 103Write the internal tracing buffer to the supplied open file descriptor. 104.It Dv FILEMON_SET_PID 105Child process ID to trace. 106.El 107.Sh RETURN VALUES 108.\" .Rv -std ioctl 109The 110.Fn ioctl 111function returns the value 0 if successful; 112otherwise the value \-1 is returned and the global variable 113.Va errno 114is set to indicate the error. 115.Sh FILES 116.Bl -tag -width ".Pa /dev/filemon" 117.It Pa /dev/filemon 118.El 119.Sh EXAMPLES 120.Bd -literal 121#include <sys/types.h> 122#include <sys/stat.h> 123#include <sys/wait.h> 124#include <sys/ioctl.h> 125#include <dev/filemon/filemon.h> 126#include <fcntl.h> 127#include <err.h> 128 129static void 130open_filemon(void) 131{ 132 pid_t child; 133 int fm_fd, fm_log; 134 135 if ((fm_fd = open("/dev/filemon", O_RDWR)) == -1) 136 err(1, "open(\e"/dev/filemon\e", O_RDWR)"); 137 if ((fm_log = open("filemon.out", 138 O_CREAT | O_WRONLY | O_TRUNC, DEFFILEMODE)) == -1) 139 err(1, "open(filemon.out)"); 140 141 if (ioctl(fm_fd, FILEMON_SET_FD, &fm_log) == -1) 142 err(1, "Cannot set filemon log file descriptor"); 143 /* Set up these two fd's to close on exec. */ 144 (void)fcntl(fm_fd, F_SETFD, FD_CLOEXEC); 145 (void)fcntl(fm_log, F_SETFD, FD_CLOEXEC); 146 147 if ((child = fork()) == 0) { 148 child = getpid(); 149 if (ioctl(fm_fd, FILEMON_SET_PID, &child) == -1) 150 err(1, "Cannot set filemon PID"); 151 /* Do something here. */ 152 return 0; 153 } else { 154 wait(&child); 155 close(fm_fd); 156 } 157 return 0; 158} 159.Ed 160.Pp 161Creates a file named 162.Pa filemon.out 163and configures the 164.Nm 165device to write the 166.Nm 167buffer contents to it. 168.Sh SEE ALSO 169.Xr dtrace 1 , 170.Xr ktrace 1 , 171.Xr truss 1 172.Sh HISTORY 173A 174.Nm 175device appeared in 176.Fx 9.1 . 177