Watch what files any Linux process accesses

whatfiles

Whatfiles is a Linux utility that logs what files other programs read/write/create/delete on your system. It traces any new processes and threads that are created as well.

Rationale:

I've long been frustrated at the lack of a simple utility to see which files a process touches from main() to exit. Whether you don't trust a software vendor or are concerned about malware, it's important to be able to know what a program or installer does to your system. lsof only observes a moment in time and strace is large and somewhat complicated.

Sample output:

mode:  read, file: /home/theron/.gimp-2.8/tool-options/gimp-clone-tool, syscall: openat(), PID: 8566, process: gimp
mode:  read, file: /home/theron/.gimp-2.8/tool-options/gimp-heal-tool, syscall: openat(), PID: 8566, process: gimp
mode:  read, file: /home/theron/.gimp-2.8/tool-options/gimp-perspective-clone-tool, syscall: openat(), PID: 8566, process: gimp
mode:  read, file: /home/theron/.gimp-2.8/tool-options/gimp-convolve-tool, syscall: openat(), PID: 8566, process: gimp
mode:  read, file: /home/theron/.gimp-2.8/tool-options/gimp-smudge-tool, syscall: openat(), PID: 8566, process: gimp
mode:  read, file: /home/theron/.gimp-2.8/tool-options/gimp-dodge-burn-tool, syscall: openat(), PID: 8566, process: gimp
mode:  read, file: /home/theron/.gimp-2.8/tool-options/gimp-desaturate-tool, syscall: openat(), PID: 8566, process: gimp
mode:  read, file: /home/theron/.gimp-2.8/plug-ins, syscall: openat(), PID: 8566, process: gimp
mode:  read, file: /usr/lib/gimp/2.0/plug-ins, syscall: openat(), PID: 8566, process: gimp
mode:  read, file: /home/theron/.gimp-2.8/pluginrc, syscall: openat(), PID: 8566, process: gimp
mode:  read, file: /usr/share/locale/en_US/LC_MESSAGES/gimp20-std-plug-ins.mo, syscall: openat(), PID: 8566, process: gimp
mode:  read, file: /usr/lib/gimp/2.0/plug-ins/script-fu, syscall: openat(), PID: 8566, process: gimp
mode:  read, file: /etc/ld.so.cache, syscall: openat(), PID: 8574, process: /usr/lib/gimp/2.0/plug-ins/script-fu
mode:  read, file: /etc/ld.so.cache, syscall: openat(), PID: 8574, process: /usr/lib/gimp/2.0/plug-ins/script-fu
mode:  read, file: /usr/lib/libgimpui-2.0.so.0, syscall: openat(), PID: 8574, process: /usr/lib/gimp/2.0/plug-ins/script-fu
mode:  read, file: /usr/lib/libgimpwidgets-2.0.so.0, syscall: openat(), PID: 8574, process: /usr/lib/gimp/2.0/plug-ins/script-fu
mode:  read, file: /usr/lib/libgimpwidgets-2.0.so.0, syscall: openat(), PID: 8574, process: /usr/lib/gimp/2.0/plug-ins/script-fu
mode:  read, file: /usr/lib/libgimp-2.0.so.0, syscall: openat(), PID: 8574, process: /usr/lib/gimp/2.0/plug-ins/script-fu
mode:  read, file: /usr/lib/libgimpcolor-2.0.so.0, syscall: openat(), PID: 8574, process: /usr/lib/gimp/2.0/plug-ins/script-fu

Use:

• basic use, launches ls and writes output to a log file in the current directory:

  $ whatfiles ls -lah ~/Documents

• specify output file location with -o :

  $ whatfiles -o MyLogFile cd ..

• include debug output, print to stdout rather than log file:

  $ whatfiles -d -s apt install zoom

• attach to currently running process (requires root privileges):

  $ sudo whatfiles -p 1234

Compilation (requires gcc and make ):

$ cd whatfiles
$ make
$ sudo make install

Questions that could be asked at some point:

• Isn't this just a reimplementation of strace -fe trace=creat,open,openat,unlink,unlinkat ./program ?

  Yes. Though it aims to be simpler and more user friendly.

• Are there Mac and Windows versions?

  No. Tracing syscalls on Mac requires task_for_pid() , which requires code signing, which I can't get to work, and anyway I have no interest in paying Apple $100/year to write free software. Process Monitor for Windows is pretty great.

Known issues:

• Seems to run slowly and occasionally freeze when used to launch Firefox and Chromium. (Attaching to both with -p [PID] once they're running works fine.)

Thank you for your interest, and please also check out Cloaker , Nestur , and Flying Carpet !