A Formally Proved, Complete Algorithm for Path Resolution with Symbolic Links

Ran Chen (1) , Martin Clochard (2, 3) , Claude Marché (2)

1 Institute of Software Chinese Academy of Sciences [Beijing]
2 TOCCATA - Formally Verified Programs, Certified Tools and Numerical Computations
3 LRI - Laboratoire de Recherche en Informatique

In the context of file systems like those of Unix, path resolution is the operation that given a character string denoting an access path, determines the target object (a file, a directory, etc.) designated by this path. This operation is not trivial because of the presence of symbolic links. Indeed, the presence of such links may induce infinite loops in the resolution process. We consider a path resolution algorithm that always terminates, detecting if it enters an infinite loop and reports a resolution failure in such a case. We propose a formal specification of path resolution and we formally prove that our algorithm terminates on any input, and is correct and complete with respect to our formal specification.

Domaines: Logique en informatique [cs.LO]

Ran Chen, Martin Clochard, Claude Marché. A Formally Proved, Complete Algorithm for Path Resolution with Symbolic Links. Journal of Formalized Reasoning, 2017, 10 (1). ⟨hal-01652148⟩