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FILEMON(4) BSD Kernel Interfaces Manual FILEMON(4) NAME filemon -- the filemon device SYNOPSIS #include <dev/filemon/filemon.h> DESCRIPTION The filemon 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' _exit(2) Note that `R' following `W' records can represent a single open(2) for R/W, or two seperate open(2) calls, one for `R' and one for `W'. IOCTLS User mode programs communicate with the filemon 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 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> static void open_filemon(void) { pid_t child; int fm_fd, fm_log; if ((fm_fd = open("/dev/filemon", O_RDWR)) == -1) err(1, "open(\"/dev/filemon\", O_RDWR)"); if ((fm_log = open("filemon.out", O_CREAT | O_WRONLY | O_TRUNC, 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"); /* Set up these two fd's to close on exec. */ (void)fcntl(fm_fd, F_SETFD, FD_CLOEXEC); (void)fcntl(fm_log, F_SETFD, FD_CLOEXEC); if ((child = fork()) == 0) { child = getpid(); if (ioctl(fm_fd, FILEMON_SET_PID, &child) == -1) err(1, "Cannot set filemon PID"); /* Do something here. */ return 0; } else { wait(&child); close(fm_fd); } return 0; } Creates a file named filemon.out and configures the filemon device to write the filemon buffer contents to it. SEE ALSO dtrace(1), ktrace(1), truss(1) HISTORY A filemon device appeared in FreeBSD 9.1. BSD May 30, 2012 BSD
NAME | SYNOPSIS | DESCRIPTION | IOCTLS | RETURN VALUES | FILES | EXAMPLES | SEE ALSO | HISTORY
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