On Wed, Jun 15, 2011 at 5:12 PM, Daniel J Walsh <dwalsh@xxxxxxxxxx> wrote: > On 06/15/2011 11:03 AM, Miloslav Trma? wrote: >> - At policy build time, precompute a DFA for all of the regexps, and >> store it in a file. This file could be mmap()ed into any user of the >> policy, requiring no malloc(), and allowing the kernel to free the >> memory when it is no longer used; this should also make loading of the >> file_contexts configuration faster. >> Mirek > > I was wondering if this was possible. Looking at the output of (semanage fcontext -l), it seems that all entries could be handled by a DFA. Of course this might mean changing the documented semantics of the regexp (in particular to forbid backreferences). The practical question is whether the DFA will be small enough, I can't really see much reason for a large state explosion - most of the regexps are very simple. > Any example of how to do it? Not really... the idea was prompted by a mention of re2c, but I suppose you don't want to involve a C compiler in the policy build process. Still, that's something to start from. (And of course, a student of automata theory should be able to build this from scratch. Perhaps a bachelor thesis?) Mirek -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel
