3.1.1 Example: Changing the Mode of the DTrace Helper Device

The following example shows how you would enable the tracing of user-space applications by users other than the root user.

# chmod 666 /dev/dtrace/helper

Alternatively, if the acl package is installed on your system, you would use an ACL rule to limit access to a specific user, for example:

# setfacl -m u:guest:rw /dev/dtrace/helper
Note

For DTrace to reference the probe points, you must change the mode on the device before the user begins running the program.

You can also create a udev rules file such as /etc/udev/rules.d/10-dtrace.rules to change the permissions on the device file each time the system boots.

The following example shows how you would change the mode of the device file by adding the following line to the udev rules file:

kernel=="dtrace/helper", MODE="0666"

The following example shows how you would change the ACL settings for the device file by adding a line similar to the following to the udev rules file:

kernel=="dtrace/helper", RUN="/usr/bin/setfacl -m u:guest:rw /dev/dtrace/helper"

To apply the udev rule without needing to restart the system, you would run the start_udev command.