< Previous | Contents | Next >
6.3.2.5. Tracing Installation Scripts
In this approach, the commands that the installation scripts perform are recorded. There are two techniques that one can use:
The LD_PRELOAD environment variable can be set to point to a library to be preloaded before installation. During installation, this library tracks the packages that are being installed by attaching itself to various executables such as cp, install, mv and tracking the system calls that modify the filesystem. For this approach to work, all the executables need to be dynamically linked without the suid or sgid bit. Preloading the library may cause some unwanted side-effects during installation. Therefore, it is advised that one performs some tests to ensure that the package manager does not break anything and logs all the appropriate files.
The second technique is to use strace, which logs all system calls made during the execution of the installation scripts.