WSFileMonitor systemtap script

dazdaz · 05-21-2011, 01:31 PM

I am trying to get this example systemtap script running, but does'nt compile.
I've made modifications etc but can't figure out what's wrong with the syntax.

I know that systemtap is functioning as I can run a few other scripts, such as

Code:

stap -e 'probe kernel.function("sys_open") {log("hello world") exit()}'

My kernel is 2.6.38-8-generic #42-Ubuntu SMP and I have the debuginfo kernel installed.

This is where I found the script :
http://sources.redhat.com/systemtap/wiki/WSFileMonitor

I have made this modification as recommended :

Code:

Eugene: Using kernel 2.6.21-1.3194.fc7, I have to change the code slightly:

  dev_nr = $file->f_path->dentry->d_inode->i_sb->s_dev
  inode_nr = $file->f_path->dentry->d_inode->i_ino

Here are the errors when I run the script.

Code:

# stap wsfile.stp
parse error: command line argument index 1 out of range [1-0]
        at: junk '$1' at wsfile.stp:9:18
     source:   if (dev_nr == ($1 << 20 | $2) # major/minor device
                              ^
parse error: command line argument index 2 out of range [1-0]
        at: junk '$2' at wsfile.stp:9:29
     source:   if (dev_nr == ($1 << 20 | $2) # major/minor device
                                         ^
parse error: command line argument index 3 out of range [1-0]
        at: unknown token '$3' at wsfile.stp:10:22
     source:       && inode_nr == $3)
                                  ^
parse error: expected 'probe', 'global', 'function', or '%{'
        saw: operator ')' at wsfile.stp:10:24
     source:       && inode_nr == $3)
                                    ^
4 parse error(s).
Pass 1: parse failed.  Try again with another '--vp 1' option.

Here is the script :

Code:

#! /usr/bin/env stap

probe kernel.function ("vfs_write"),
      kernel.function ("vfs_read")
{
  dev_nr = $file->f_path->d_inode->i_sb->s_dev
  inode_nr = $file->f_path->d_inode->i_ino

  if (dev_nr == ($1 << 20 | $2) # major/minor device
      && inode_nr == $3)
    printf ("%s(%d) %s 0x%x/%u\n",
      execname(), pid(), probefunc(), dev_nr, inode_nr)
}

Nominal Animal · 05-22-2011, 05:45 PM

Quote:

Originally Posted by dazdaz

Code:

if (dev_nr == ($1 << 20 | $2) # major/minor device
      && inode_nr == $3)

What are $1, $2, and $3 supposed to be? Are you sure you don't mean @1, @2, and @3, respectively?

I recommend you take a look at the sizeof.stp systemtap example.

dazdaz · 05-23-2011, 02:22 PM

systemtap complains when I change the $ to an @. I know it should be run like this, but for me it does'nt seem to work.

Code:

script.stp arg1 arg2 arg3.