SYNOPSIS

In dev/filemon/filemon.h

DESCRIPTION

The device allows a process to collect file operations data of its children. The device /dev/filemon responds to two ioctl(2) calls.

System calls are denoted using the following single letters:

`C'

chdir(2)

`D'

unlink(2)

`E'

exec(2)

`F'

fork(2), vfork(2)

`L'

link(2), linkat(2), symlink(2), symlinkat(2)

`M'

rename(2)

`R'

open(2) for read

`S'

stat(2)

`W'

open(2) for write

`X'

_exit2

Note that `R' following `W' records can represent a single open(2) for R/W, or two separate open(2) calls, one for `R' and one for `W' Note that only successful system calls are captured.

IOCTLS

User mode programs communicate with the driver through a number of ioctls which are described below. Each takes a single argument.

FILEMON_SET_FD

Write the internal tracing buffer to the supplied open file descriptor.

FILEMON_SET_PID

Child process ID to trace.

RETURN VALUES

The Fn ioctl function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

FILES

/dev/filemon

EXAMPLES

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/ioctl.h>
#include <dev/filemon/filemon.h>
#include <fcntl.h>
#include <err.h>
#include <unistd.h>
static void
open_filemon(void)
{
        pid_t child;
        int fm_fd, fm_log;
        if ((fm_fd = open("/dev/filemon", O_RDWR | O_CLOEXEC)) == -1)
                err(1, "open(\"/dev/filemon\", O_RDWR)");
        if ((fm_log = open("filemon.out",
            O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC, DEFFILEMODE)) == -1)
                err(1, "open(filemon.out)");
        if (ioctl(fm_fd, FILEMON_SET_FD, &fm_log) == -1)
                err(1, "Cannot set filemon log file descriptor");
        if ((child = fork()) == 0) {
                child = getpid();
                if (ioctl(fm_fd, FILEMON_SET_PID, &child) == -1)
                        err(1, "Cannot set filemon PID");
                /* Do something here. */
        } else {
                wait(&child);
                close(fm_fd);
        }
}

Creates a file named filemon.out and configures the device to write the buffer contents to it.

HISTORY

A device appeared in Fx 9.1 .