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Comment by westurner

3 months ago

On MacOS:

  sudo dtrace -n 'vfs::*:entry { printf("%-16s %-6d %s", execname, pid, probefunc); }'

  sudo dtrace -n 'vfs:lookup:entry { printf("%-16s %-6d %s", execname, pid, copyinstr(arg1)); }'

TIL Dtrace is included in recent builds of Windows 11 and Server 2025: https://learn.microsoft.com/en-us/windows-hardware/drivers/d... ;

  # Must be run as Administrator
  dtrace -n "syscall::NtCreateFile:entry, syscall::NtReadFile:entry, syscall::NtWriteFile:entry { printf(\"%s (%d) - %s\", execname, pid, probefunc); }"

It's possible to trace file system calls in Windows with procmon.exe by saving a .pmc config file and then loading it from the CLI:

  procmon.exe
  # uncheck everything except "Show File System Activity"
  # Filter > Drop Filtered Events
  # File > Export Configuration...

  # Must be run as Administrator
  procmon.exe /AcceptEula /Quiet /Minimized /LoadConfig C:\Tools\fs-only.pmc /BackingFile C:\Logs\FileSystemTrace.pml

It's also possible to trace lower level file system calls in Windows with logman.exe but it's necessary to parse the traces that it generates.

Then with just bpftrace on Linux:

  sudo bpftrace -e 'tracepoint:syscalls:sys_enter_openat { printf("%-6d %-16s %s\n", pid, comm, str(args.filename)); }'

  sudo bpftrace -e 'kprobe:vfs_read, kprobe:vfs_write, kprobe:vfs_open { printf("%-16s %-6d %s\n", comm, pid, probefunc); }'

... According to 2.5pro on the cli strs

strace, dtrace, and bpftrace could have a --diff-fs-syscall-files option.

great insights, i'll read up on it and see if it can be useful, thx