1. 04 Nov, 2015 1 commit
  2. 03 Nov, 2015 1 commit
    • David Johnson's avatar
      Refactor libcap to allow both user lib and kernel module builds. · ab9ac0a0
      David Johnson authored
      Mostly, I kept the existing source skeletons in cap.c and
      cptr_cache.c (they've just moved to src/common), but all the
      user/kernel include differences are nicely factored out.  You
      might think my organization is a bit schizophrenic (a flattened
      include/ dir, and a hierarchical src/ dir), but I do that because
      I don't particularly care for libraries that install headers in
      $PREFIX/include/libfoo/{subdir1,subdir2,...}.  The idea with the
      src/ dir is that common cap/cptr logic goes in src/common, and
      any "platform" specialization (user lib vs kernel mod) goes in
      src/user or src/kernel .  The libcap.h and libcap_internal.h
      headers define some common types, macros, and functions, and expect
      the platform headers and source files to specialize them.
      
      I added a very basic notion of capability object types and tied it
      to revocation and deletion in the same way the original library did.
      
      For userspace, since I didn't have atomic ops, I just did basically
      what the kernel does, a cache-aware spinlock thing, but used pthread
      spinlocks (what does that even mean) in hopes they could do something
      smart internally.  Silly me, glib actually has atomic ops.  Anyway, I
      had to do that to restore atomic bit ops to userspace.
      
      Obviously, I got rid of all the LCD-specific stuff.
      
      Most of the build happens via automake, but you'll notice the
      src/kernel/Makefile.in .  That's not a checkin mistake; the kernel
      build makefiles don't play nicely with autofoo.  That Makefile just
      calls into the kernel module build process in the normal way.  Of
      course, we have to do some autofoo to arrange the sources and the
      Makefile to be in the same dir... stinky.  See src/kernel/Makefile.in .
      
      For now, we haven't committed the generated .in files; use
      autogen.sh as described in INSTALL.  That will probably change
      down the road.
      
      I mostly left the examples unchanged, although I added some locking
      to the multithread example and abstracted out its thread operations
      so you're not locked into 20k threads; it scales.  I also tried to
      make the grant/revoke operations wait until the slots had been
      constructed.  This extra locking and care has the effect of
      reducing the paralellism, I suppose, but not enough to detract from
      the test, I think.  We'll see.
      ab9ac0a0